tag:theconversation.com,2011:/ca/topics/fungi-2464/articlesFungi – The Conversation2024-03-27T16:02:40Ztag:theconversation.com,2011:article/2257002024-03-27T16:02:40Z2024-03-27T16:02:40ZHazardous mould contaminates many food staples – what you should know about mycotoxins<p><em>Mycotoxins are substances produced by mould that poison food. They are <a href="https://academic.oup.com/carcin/article/31/1/71/2392129">harmful</a> to humans and animals when consumed. According to the Food and Agricultural Organisation (FAO), about 25% of the world’s agricultural harvests are <a href="https://pureadmin.qub.ac.uk/ws/files/185127566/Worldwide_contamination_of_food_crops_with_mycotoxins_Validity_of_the_widely_cited_FAO_estimate_of_25.pdf">contaminated</a> by mycotoxins. Though reliable data is lacking, mycotoxin contamination is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108760/">widespread in Africa</a>. It often takes the form of aflatoxin in cereal crops and has led to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6354945/#:%7E:text=They%20have%20the%20ability%20to,of%20humans%20annually%20(15).">health issues</a> such as chronic gastritis, diarrhoea, kidney problems and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3699030/">liver cancer</a>. Biologist Oluwadara Pelumi Omotayo <a href="https://www.sciencedirect.com/science/article/pii/S2214750018307315">studied</a> how mycotoxins contaminate ginger in South Africa. We asked her to explain what they are and how to avoid the danger.</em></p>
<hr>
<h2>What are mycotoxins?</h2>
<p>Mycotoxins are hazardous substances produced by certain microorganisms called toxigenic fungi (<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108760/">moulds</a>). </p>
<p>One mould species may produce more than one type of mycotoxin, and a single mycotoxin may be produced by several mould species. Mycotoxins are ubiquitous. They can be found indoors and outdoors, thriving in warm and highly humid areas. They are usually toxic to living things. </p>
<p>Contamination can lead to variety of illnesses, and even death. They can cause <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108760/">cancer</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780323870313000305">hepatic diseases</a>, deterioration of the <a href="https://journals.sagepub.com/doi/abs/10.1191/0960327103ht328oa">kidneys</a>, <a href="https://journals.sagepub.com/doi/abs/10.1191/0960327103ht328oa">nephropathy</a>, and <a href="https://core.ac.uk/download/481757543.pdf">alimentary toxic aleukia</a>, a potentially fatal illness marked by nausea, vomiting, diarrhoea and skin inflammation. They can also impair an animal’s immune system, decrease milk production, cause stunted growth and weight loss, and induce gastroenteritis. </p>
<p>Mycotoxins have been reported to be responsible for numerous human deaths. For example, in 2004, Kenya <a href="https://www.devex.com/news/kenyans-love-maize-but-aflatoxins-are-making-it-dangerous-96279">recorded</a> an outbreak of aflatoxin poisoning which led to the death of about 125 people.</p>
<p>Mycotoxins drastically suppress the immune system. And a single mycotoxin, even in minute quantities, can result in acute poisoning in humans and animals.</p>
<p>Over 300 types of mycotoxins have been identified so far, including the notable aflatoxin and other types like ochratoxin and fumonisin, which often contaminate grains like maize. </p>
<h2>How do humans come in contact with mycotoxin?</h2>
<p>People can be exposed to mycotoxins through eating contaminated food and through contact and absorption through the skin. Exposure can also happen through inhalation of polluted air, as they can be present in airborne particles such as fungal spores.</p>
<p>Human exposure to mycotoxins can come from plant-based food and from the carry-over of mycotoxins and their metabolites in animal products such as meats.</p>
<p>Food items that can be tainted include spices, grains (such as maize, rice and sorghum), nuts, fruits (dry or fresh), coffee beans, cocoa seeds, vegetables and rhizomes like ginger.</p>
<h2>Why should we be concerned about mycotoxins?</h2>
<p>Mycotoxin contamination is widespread, especially in African countries. The toxins exist even in medicinal plants and herbs. This was confirmed by our <a href="https://www.sciencedirect.com/science/article/pii/S2214750018307315">study</a>, which investigated the presence of mycotoxin in ginger. </p>
<p>Ginger has been used since antiquity for the treatment of various ailments such as colds, migraines and gastrointestinal tract disorders. However, like other spices and herbs, it has been reported to contain mycotoxins. Ginger has been found to contain aflatoxin and ochratoxin A (which is known to be teratogenic: capable of causing developmental abnormalities in unborn foetuses). </p>
<p>From our study, aflatoxins B1, B2, G1 and G2 and ochratoxin A were found in ginger collected from the North-West province of South Africa in summer and winter. Though at varying concentrations, the highest concentration was observed in summer. This indicates that there’s no period when crops and plants, including ginger, would necessarily be completely free from mycotoxins.</p>
<h2>How do farmers and consumers know that a crop has been contaminated?</h2>
<p>Mycotoxins are not visible to the naked eye. The invasion of crops and foods by moulds is an indication that they are potentially contaminated with mycotoxins. </p>
<p>Farmers and consumers should inspect food crops for evidence of moulds, and discard crops and food that have mould growth. </p>
<h2>What can be done to prevent mycotoxin contamination?</h2>
<p>To minimise the risk of mycotoxin exposure and contamination, we recommend action before and after harvest and storage.</p>
<ul>
<li><p>Prevent mycotoxin/fungi invasion while the crops are still in the field. This can be achieved by cultivating and harvesting at the appropriate time. Adopt techniques that reduce stress in plants, such as ensuring they get enough water and are well spaced. They also need adequate sunlight and should be cultivated on suitable soil. It is also important to avoid using agricultural residues as compost as they can produce toxigenic fungi and mycotoxins when decaying.</p></li>
<li><p>After harvest, reduce fungal contamination and mycotoxin production in foods during storage, handling, processing and transport. Facilities should be monitored and kept at temperatures that discourage mould growth. Crops with moulds should be sorted and removed before storage. Storage facilities must be aerated and dry. Reducing moisture content in crops before storage is important to prevent mould.</p></li>
<li><p>Avoid damage to grains before storing as damaged grain is more susceptible to mould growth and mycotoxin contamination.</p></li>
<li><p>Don’t store food too long before consumption. It is important to follow recommended guidelines for safely storing <a href="https://www.foodsafety.gov/food-safety-charts/cold-food-storage-charts">cooked and raw food</a> in the <a href="https://www.foodsafety.gov/food-safety-charts/food-safety-during-power-outage">refrigerator</a>, <a href="https://www.agric.wa.gov.au/fruit/storage-fresh-fruit-and-vegetables?nopaging=1">fruits and vegetables</a>, <a href="https://wholegrainscouncil.org/recipes/cooking-whole-grains/storing-whole-grains">grains</a>, <a href="https://wildlyorganic.com/blogs/recipes/how-long-do-nuts-last-tips-for-storing-nuts-and-seeds">nuts and seeds</a>, and spices such as <a href="https://eatbydate.com/other/spice-menu/how-long-does-ginger-last-shelf-life/">ginger</a>. </p></li>
<li><p>Inspect and discard foods contaminated by moulds. </p></li>
<li><p>Ensure contaminated foods are not sold to consumers.</p></li>
<li><p>Improve awareness about mycotoxin contamination.</p></li>
</ul><img src="https://counter.theconversation.com/content/225700/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Oluwadara Pelumi Omotayo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Mycotoxins contamination causes health issues. Paying attention to storage of agricultural produce can save many lives.Oluwadara Pelumi Omotayo, Postdoctoral Research Fellow, North-West UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221082024-03-22T12:34:47Z2024-03-22T12:34:47ZClimate change is shifting the zones where plants grow – here’s what that could mean for your garden<figure><img src="https://images.theconversation.com/files/583569/original/file-20240321-20-wkg9tp.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4019%2C2474&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change complicates plant choices and care. Early flowering and late freezes can kill flowers like these magnolia blossoms.</span> <span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>With the <a href="https://www.pbs.org/newshour/science/the-vernal-equinox-marks-the-first-day-of-spring-what-does-that-mean">arrival of spring</a> in North America, many people are gravitating to the gardening and landscaping section of home improvement stores, where displays are overstocked with eye-catching seed packs and benches are filled with potted annuals and perennials. </p>
<p>But some plants that once thrived in your yard may not flourish there now. To understand why, look to the U.S. Department of Agriculture’s recent update of its <a href="https://planthardiness.ars.usda.gov/">plant hardiness zone map</a>, which has long helped gardeners and growers figure out which plants are most likely to thrive in a given location. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A U.S. map divided into colored geographic zones with a numbered key." src="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 2023 USDA plant hardiness zone map shows the areas where plants can be expected to grow, based on extreme winter temperatures. Darker shades (purple to blue) denote colder zones, phasing southward into temperate (green) and warm zones (yellow and orange).</span>
<span class="attribution"><a class="source" href="https://planthardiness.ars.usda.gov/">USDA</a></span>
</figcaption>
</figure>
<p>Comparing the 2023 map to the previous version from 2012 clearly shows that as climate change warms the Earth, plant hardiness zones are shifting northward. On average, the coldest days of winter in our current climate, based on temperature records from 1991 through 2020, are 5 degrees Fahrenheit (2.8 Celsius) warmer than they were between 1976 and 2005. </p>
<p>In some areas, including the central Appalachians, northern New England and north central Idaho, winter temperatures have warmed by 1.5 hardiness zones – 15 degrees F (8.3 C) – over the same 30-year window. This warming changes the zones in which plants, whether annual or perennial, will ultimately succeed in a climate on the move.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="U.S. map showing large areas colored tan, denoting a 5-degree increase in average winter minimum temperatures." src="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map shows how plant hardiness zones have shifted northward from the 2012 to the 2023 USDA maps. A half-zone change corresponds to a tan area. Areas in white indicate zones that experienced minimal change.</span>
<span class="attribution"><a class="source" href="https://site.extension.uga.edu/climate/2023/11/new-usda-plant-hardiness-zone-map-shows-most-of-southeast-has-gotten-one-half-zone-warmer/">Prism Climate Group, Oregon State University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>As a <a href="https://scholar.google.com/citations?user=frEPl6IAAAAJ&hl=en">plant pathologist</a>, I have devoted my career to understanding and addressing plant health issues. Many stresses not only shorten the lives of plants, but also affect their growth and productivity. </p>
<p>I am also a gardener who has seen firsthand how warming temperatures, pests and disease affect my annual harvest. By understanding climate change impacts on plant communities, you can help your garden reach its full potential in a warming world.</p>
<h2>Hotter summers, warmer winters</h2>
<p>There’s no question that the temperature trend is upward. From 2014 through 2023, the world experienced the <a href="https://www.noaa.gov/news/world-just-sweltered-through-its-hottest-august-on-record">10 hottest summers ever recorded</a> in 174 years of climate data. Just a few months of sweltering, unrelenting heat can significantly affect plant health, especially <a href="https://extension.psu.edu/cool-season-vs-warm-season-vegetables">cool-season garden crops</a> like broccoli, carrots, radishes and kale. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Radishes sprouting in a garden bed." src="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radishes are cool-season garden crops that cannot withstand the hottest days of summer.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Winters are also warming, and this matters for plants. The USDA defines plant hardiness zones based on the coldest average annual temperature in winter at a given location. Each zone represents a 10-degree F range, with zones numbered from 1 (coldest) to 13 (warmest). Zones are divided into 5-degree F half zones, which are lettered “a” (northern) or “b” (southern). </p>
<p>For example, the coldest hardiness zone in the lower 48 states on <a href="https://planthardiness.ars.usda.gov/">the new map</a>, 3a, covers small pockets in the northernmost parts of Minnesota and has winter extreme temperatures of -40 F to -35 F. The warmest zone, 11b, is in Key West, Florida, where the coldest annual lows range from 45 F to 50 F. </p>
<p>On the <a href="https://planthardiness.ars.usda.gov/system/files/US_Map_2012.jpg">2012 map</a>, northern Minnesota had a much more extensive and continuous zone 3a. North Dakota also had areas designated in this same zone, but those regions now have shifted completely into Canada. Zone 10b once covered the southern tip of mainland Florida, including Miami and Fort Lauderdale, but has now been pushed northward by a rapidly encroaching zone 11a. </p>
<p>Many people buy seeds or seedlings without thinking about hardiness zones, planting dates or disease risks. But when plants have to contend with temperature shifts, heat stress and disease, they will eventually struggle to survive in areas where they once thrived. </p>
<p>Successful gardening is still possible, though. Here are some things to consider before you plant:</p>
<h2>Annuals versus perennials</h2>
<p>Hardiness zones matter far less for <a href="https://www.britannica.com/science/annual">annual plants</a>, which germinate, flower and die in a single growing season, than for <a href="https://www.britannica.com/science/perennial">perennial plants</a> that last for several years. Annuals typically avoid the lethal winter temperatures that define plant hardiness zones. </p>
<p>In fact, most annual seed packs don’t even list the plants’ hardiness zones. Instead, they provide sowing date guidelines by geographic region. It’s still important to follow those dates, which help ensure that frost-tender crops are not planted too early and that cool-season crops are not harvested too late in the year.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Orange flowers blooming with other plants and grasses." src="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">California poppies are typically grown as annuals in cool areas, but can survive for several years in hardiness zones 8-10.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/FWtHc">The Marmot/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>User-friendly perennials have broad hardiness zones</h2>
<p>Many perennials can grow across wide temperature ranges. For example, hardy fig and hardy kiwifruit grow well in zones 4-8, an area that includes most of the Northeast, Midwest and Plains states. Raspberries are hardy in zones 3-9, and blackberries are hardy in zones 5-9. This eliminates a lot of guesswork for most gardeners, since a majority of U.S. states are dominated by two or more of these zones. </p>
<p>Nevertheless, it’s important to pay attention to plant tags to avoid selecting a variety or cultivar with a restricted hardiness zone over another with greater flexibility. Also, pay attention to instructions about proper sun exposure and planting dates after the last frost in your area. </p>
<h2>Fruit trees are sensitive to temperature fluctuations</h2>
<p>Fruit trees have two parts, the rootstock and the scion wood, that are <a href="https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource003733_Rep5323.pdf">grafted together to form a single tree</a>. Rootstocks, which consist mainly of a root system, determine the tree’s size, timing of flowering and tolerance of soil-dwelling pests and pathogens. Scion wood, which supports the flowers and fruit, determines the fruit variety. </p>
<p>Most commercially available fruit trees can tolerate a wide range of hardiness zones. However, stone fruits like peaches, plums and cherries are more sensitive to temperature fluctuations within those zones – particularly abrupt swings in winter temperatures that create unpredictable freeze-thaw events. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Packages for hardy fig and kiwi seedlings." src="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Following planting instructions carefully can maximize plants’ chances of success.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These seesaw weather episodes affect all types of fruit trees, but stone fruits appear to be more susceptible, possibly because they flower earlier in spring, have fewer hardy rootstock options, or have bark characteristics that make them more vulnerable to winter injury. </p>
<p>Perennial plants’ hardiness increases through the seasons in a process called <a href="https://extension.umd.edu/resource/hardening-vegetable-seedlings-home-garden/">hardening off</a>, which conditions them for harsher temperatures, moisture loss in sun and wind, and full sun exposure. But a too-sudden autumn temperature drop can cause plants to die back in winter, an event known as <a href="https://extension.psu.edu/winterkill-of-turfgrasses">winter kill</a>. Similarly, a sudden spring temperature spike can lead to premature flowering and subsequent frost kill.</p>
<h2>Pests are moving north too</h2>
<p>Plants aren’t the only organisms constrained by temperature. With milder winters, southern insect pests and plant pathogens are expanding their ranges northward. </p>
<p>One example is <a href="https://www.britannica.com/science/blight">Southern blight</a>, a stem and root rot disease that affects 500 plant species and is caused by a fungus, <em>Agroathelia rolfsii</em>. It’s often thought of as affecting hot Southern gardens, but has become more commonplace recently in the Northeast U.S. on tomatoes, <a href="https://theconversation.com/how-to-keep-your-jack-o-lantern-from-turning-into-moldy-maggoty-mush-before-halloween-190526">pumpkins and squash</a>, and other crops, including <a href="https://extension.psu.edu/apple-disease-southern-blight">apples in Pennsylvania</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A stem dotted with small round growths." src="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Southern blight (small round fungal structures) at the base of a tomato plant.</span>
<span class="attribution"><a class="source" href="https://ag.purdue.edu/department/arge/swpap/southern-blight-tomato.html">Purdue University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Other plant pathogens may take advantage of milder winter temperatures, which leads to prolonged saturation of soils instead of freezing. Both plants and microbes are less active when soil is frozen, but in wet soil, microbes have an opportunity to colonize dormant perennial plant roots, leading to more disease.</p>
<p>It can be challenging to accept that climate change is stressing some of your garden favorites, but there are thousands of varieties of plants to suit both your interests and your hardiness zone. Growing plants is an opportunity to <a href="https://theconversation.com/take-a-break-from-your-screen-and-look-at-plants-botanizing-is-a-great-way-to-engage-with-life-around-you-210616">admire their flexibility</a> and the features that enable many of them to thrive in a world of change.</p><img src="https://counter.theconversation.com/content/222108/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from the US Department of Agriculture.</span></em></p>The US Department of Agriculture has updated its plant hardiness zone map, which shows where various plants will grow across the country. Gardeners should take note.Matt Kasson, Associate Professor of Mycology and Plant Pathology, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202802024-03-01T00:15:33Z2024-03-01T00:15:33ZWhy and how often do I need to wash makeup brushes and sponges?<figure><img src="https://images.theconversation.com/files/576120/original/file-20240216-24-9aako6.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C4928%2C3268&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/@anniespratt?utm_content=creditCopyText&utm_medium=referral&utm_source=unsplash">Annie Spratt</a> on <a href="https://unsplash.com/photos/selective-focus-photography-of-woman-applying-blush-on-on-her-face-xOEmZX6YSu8">Annie Spratt/Unsplash</a></span></figcaption></figure><p>From the bristles of brushes to the porous surfaces of sponges, your makeup kit can harbour a host of bacteria and fungi.</p>
<p>These potentially hazardous contaminants can originate not only from the cosmetics themselves, but also from the very surface of our skin. </p>
<p>So, how can we keep things hygienic and avoid microbial growth on makeup brushes and sponges? Here’s what you need to know.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-micellar-water-and-how-does-it-work-219492">What is micellar water and how does it work?</a>
</strong>
</em>
</p>
<hr>
<h2>How do germs and fungi get in my brushes and sponges?</h2>
<p>Germs and fungi can make their way into your makeup kit in lots of ways. </p>
<p>Ever flushed a toilet with the lid open with your makeup brushes nearby? There’s a good chance <a href="https://theconversation.com/mobile-phones-are-covered-in-germs-disinfecting-them-daily-could-help-stop-diseases-spreading-135318">faecal particles</a> have landed on them. </p>
<p>Perhaps a family member or housemate has used your eyeshadow brush when you weren’t looking, and transferred some microbes across in the process. </p>
<p>Bacteria that trigger a pimple outbreak can be easily transferred from the surface of your skin to a makeup brush or sponge. </p>
<p>And tiny little mites called Demodex mites, which have been linked to certain rashes and acne, live on your skin, as well, and so may end up in your sponge or brushes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A young Asian man applies makeup at a cluttered vanity." src="https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=316&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=316&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=316&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=397&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=397&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579069/original/file-20240229-16-csz1bk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=397&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Germs and fungi can make their way into your makeup in lots of ways.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/gay-queer-man-nonbinary-beauty-blogger-2361479535">Chay_Tee/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/invisible-skin-mites-called-demodex-almost-certainly-live-on-your-face-but-what-about-your-mascara-195451">Invisible skin mites called Demodex almost certainly live on your face – but what about your mascara?</a>
</strong>
</em>
</p>
<hr>
<p>Bacterial contamination of <a href="https://pubmed.ncbi.nlm.nih.gov/38020232/">lip cosmetics</a>, in particular, can pose a risk of skin and eye infections (so keep that in mind if you use lip brushes). Lipsticks are frequently contaminated with bacteria such as <em>Staphylococcus aureus</em>, <em>E. coli</em>, and <em>Streptococcus pneumoniae</em>.</p>
<p>Low-quality cosmetics are more likely to have higher and more diverse microbial growth compared to <a href="https://www.sciencedirect.com/science/article/pii/S1319562X23002978?pes=vor">high-quality cosmetics</a>.</p>
<p>Brushes exposed to sensitive areas like the eyes, mouth and nose are particularly susceptible to being potential sources of infection. </p>
<p>The range of conditions caused by these microorganisms includes:</p>
<ul>
<li><p>abscesses</p></li>
<li><p>skin and soft tissue infections</p></li>
<li><p>skin lesions</p></li>
<li><p>rashes</p></li>
<li><p>and dermatitis.</p></li>
</ul>
<p>In severe cases, infections can lead to invasion of the bloodstream or deep tissues. </p>
<p>Commercially available cosmetics contain varying amounts and types of preservatives aimed at inhibiting the growth of fungi and bacteria.</p>
<p>But when you apply makeup, different cosmetics with unique formulations of preservatives can become mixed. When a preservative meant for one product mixes with others, it might not work as well because they have different water amounts or pH levels.</p>
<p>So preservatives are not foolproof. We also need to observe good hygiene practices when it comes to brushes and other cosmetics applicators. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman washes a makeup brush in a sink." src="https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576113/original/file-20240216-16-qqim5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">You don’t need to use micellar water to clean your brushes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-washing-makeup-brush-under-water-2020030193">Pixel-Shot/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Keeping brushes clean</h2>
<p>Start with the basics: never <a href="https://www.semanticscholar.org/paper/Isolation-of-Pathogenic-Microbes-from-Beauty-Salons-Hassan-Hamad/0199635290628fe326fcd04a2b8a2422884a8240">share makeup brushes or sponges</a>. Everyone carries different microbes on their skin, so sharing brushes and sponges means you are also sharing germs and fungi.</p>
<p>If you need to share makeup, use something disposable to apply it, or make sure any shared brushes are washed and sterilised before the next person uses it.</p>
<p>Clean makeup brushes by washing with hot soapy water and rinsing thoroughly.</p>
<p>How often? Stick to a cleaning routine you can repeat with consistency (as opposed to a deep clean that is done annually). <a href="https://www.aad.org/public/everyday-care/skin-care-secrets/routine/clean-your-makeup-brushes#:%7E:text=To%20protect%20your%20skin%20and,every%207%20to%2010%20days.">Once a week</a> might be a good goal for some, while others may need to wash more regularly if they are heavy users of makeup. </p>
<p>Definitely wash straight away if someone else has used your brushes or sponges. And if you’ve had an eye infection such as conjunctivitis, ensure you clean applicators thoroughly after the infection has resolved. </p>
<p>You can use bactericidal soap, 70% ethanol or chlorhexidine solutions to wash. Just make sure you wash very thoroughly with hot water after, as some of these things can irritate your skin. (While some people online say alcohol can degrade brushes and sponges, opinion seems to be mixed; in general, most disinfectants are unlikely to cause significant corrosion.)</p>
<p>For some brushes, heating or steaming them and letting them dry may also be an effective sterilisation method once they are washed with detergent. Microwaving sponges isn’t a good idea because while the heat generated by a domestic microwave would kill microbes, it would need temperatures approaching 100°C for a decent period of time (at least several minutes). The heat could melt some parts of the sponge and hot materials could be a scalding hazard.</p>
<p>Once clean, ensure brushes and sponges are stored in a dry place away from water sources (and not near an open toilet).</p>
<p>If you’re having makeup applied professionally, brushes and applicators should be sterilised or changed from person to person. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bunch of makeup brushes are set out to dry on a towel." src="https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576114/original/file-20240216-30-c04ns7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dry brushes thoroughly after washing.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/after-cleaning-makeup-brushes-finish-will-653637367">prachyaloyfar/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Should I wash them with micellar water?</h2>
<p>No. </p>
<p>Not only is this expensive, it’s unnecessary. The same benefits can be achieved with cheaper detergents or alcohol (just rinse brushes carefully afterwards).</p>
<p>Disinfection methods such as using bactericidal soap, 70% ethanol, or chlorhexidine are all very good at reducing the amount of microbes on your brushes and sponges.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-micellar-water-and-how-does-it-work-219492">What is micellar water and how does it work?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/220280/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rosalie Hocking is currently the recipient of an Australian government Future Fellowship.
</span></em></p><p class="fine-print"><em><span>Enzo Palombo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Yes, you need to wash them but no, you don’t need to use micellar water to do it.Enzo Palombo, Professor of Microbiology, Swinburne University of TechnologyRosalie Hocking, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2226102024-02-14T23:50:02Z2024-02-14T23:50:02ZAustralia’s shot-hole borer beetle invasion has begun, but we don’t need to chop down every tree under attack<figure><img src="https://images.theconversation.com/files/574604/original/file-20240209-18-7stpt1.jpg?ixlib=rb-1.1.0&rect=46%2C0%2C6183%2C4147&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shotgunlike-lesions-on-tree-bark-trunk-1754480912">jgeyser, Shutterstock</a></span></figcaption></figure><p>A <a href="https://www.agric.wa.gov.au/borer">new pest attacking Perth’s trees</a> threatens to <a href="https://www.outbreak.gov.au/current-outbreaks/polyphagous-shot-hole-borer">spread across Australia</a>, damaging crops and native forests as well as our urban forest. To control its spread, the Western Australian government is <a href="https://www.watoday.com.au/national/western-australia/absolutely-devastating-a-tiny-exotic-beetle-will-see-180-of-hyde-park-s-trees-cut-down-20240130-p5f16n.html">chopping down hundreds of established trees</a>. But these losses may be in vain. </p>
<p>Originally from southeast Asia, the polyphagous (meaning “many-eating”) shot-hole borer has <a href="https://doi.org/10.1079/cabicompendium.18360453">invaded several countries</a>. It attacks <a href="https://www.agric.wa.gov.au/sites/gateway/files/PSHB-WA-Host-List.pdf">more than 400 tree species</a>, including <a href="https://www.agric.wa.gov.au/sites/gateway/files/PSHB-Global-Host-List.pdf">crops</a> such as apple, avocado, macadamia and mango. <a href="https://doi.org/10.3389/ffgc.2021.654702">Trees grown for timber</a>, such as ash, elms and oaks are not safe either. And with every new country it invades, it threatens an increasingly large number of native trees.</p>
<p>Australia plans to <a href="https://www.watoday.com.au/national/western-australia/absolutely-devastating-a-tiny-exotic-beetle-will-see-180-of-hyde-park-s-trees-cut-down-20240130-p5f16n.html">eradicate this pest using one method: felling established trees</a>. But the borer has been eradicated only once – in <a href="https://doi.org/10.1007/s10530-022-02929-w">isolated tropical glasshouses in frosty Europe</a> – demonstrating the difficulty of eradication from larger agricultural and natural ecosystems.</p>
<p>To achieve this worthy but difficult goal, everyone will need to work together. We need a wide range of experts to fully evaluate all available control methods, and consider the most appropriate time frame for eradication. Understanding the impacts of both the pest and its management will ensure we get the best possible outcomes in both the short and long term.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1744269134043464069"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/trees-in-south-africa-are-under-attack-why-its-proving-hard-to-manage-130804">Trees in South Africa are under attack. Why it's proving hard to manage</a>
</strong>
</em>
</p>
<hr>
<h2>The nature of the beast(s)</h2>
<p>The borer probably arrived in Australia as a stowaway with <a href="https://www.abc.net.au/news/2024-01-30/shot-hole-borer-attacks-hyde-park-trees/103406280">untreated wood</a> and remained undetected until August 2021, when a <a href="https://www.wa.gov.au/government/announcements/fremantle-residents-asked-look-exotic-insect-borer">concerned resident of East Fremantle</a> noticed unusual holes in her backyard maple trees. Now <a href="https://www.abc.net.au/news/2024-01-30/shot-hole-borer-attacks-hyde-park-trees/103406280">more than 80 suburbs</a> in 25 councils are affected. Fortunately, the pest has not yet been detected outside the Perth metropolitan area.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of Perth and the Polyphagous shot-hole borer quarantine area" src="https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=848&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=848&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=848&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1066&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1066&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575134/original/file-20240212-24-1b1k45.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1066&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The pest borer quarantine area covers 25 local government areas in Perth.</span>
<span class="attribution"><a class="source" href="https://www.agric.wa.gov.au/borer">Department of Primary Industries and Regional Development</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The borer attacks so many tree species because it has an accomplice, in the <a href="https://doi.org/10.1016/j.fgb.2013.04.004">form of a fungus</a>. The two live in a mutually dependent “symbiotic” relationship. </p>
<p>The borer creates a Swiss cheese-like matrix of tunnels through the wood. The fungus feeds on the wood lining the tunnels as it grows, and the borer eats the fungus. </p>
<p>The tunnels weaken the structure of the wood, but tree death occurs when the fungus invades and blocks the <a href="https://doi.org/10.1038/s41598-023-48809-8">flow of water and sap between roots and leaves</a>.</p>
<p>The borer’s small size likely limits its natural rate of spread, however we <a href="https://doi.org/10.1111/afe.12321">don’t know how far it can fly</a>. There is a risk of human-assisted spread over long distances as the borer can survive in <a href="https://doi.org/10.1093/ee/nvaa103">small pieces of wood for weeks</a>. To make matters worse, a single female borer can <a href="https://doi.org/10.1111/afe.12155">produce offspring without a mate</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Six development stages of the shot hole borer, arranged in a circle to show the life cycle, on a white background" src="https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=560&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=560&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=560&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=704&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=704&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574813/original/file-20240211-22-c36zto.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=704&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The life cycle of the polyphagous shot-hole borer, also known as the Asian ambrosia beetle (<em>Euwallacea fornicatus</em>)</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/development-stages-asian-ambrosia-beetle-euwallacea-513402742">Protasov AN, Shutterstock</a></span>
</figcaption>
</figure>
<h2>Responding to the threat in Australia</h2>
<p>The threat to Australia can be estimated from the experience in other invaded locations. As in Perth, the invasion usually begins in cities, then spreads into the surrounding countryside, attacking horticulture and forests, including <a href="https://doi.org/10.1007/s12600-012-0223-7">avocado production in Israel</a> and <a href="https://doi.org/10.1094/PDIS-03-12-0276-PDN">California</a> and <a href="https://doi.org/10.1007/s13314-023-00524-z">stone fruit in South Africa</a>. This overseas experience has informed models of <a href="https://doi.org/10.1111/afe.12566">potential impacts for WA</a>.</p>
<p>But local effects are hard to predict. Figs and eucalypts not susceptible in <a href="https://doi.org/10.3389/ffgc.2021.654702">California and Israel</a>, yet <a href="https://www.agric.wa.gov.au/sites/gateway/files/PSHB-WA-Host-List.pdf">figs are preferred and some eucalypts are susceptible in WA</a>.</p>
<p>The <a href="https://www.outbreak.gov.au/current-outbreaks/polyphagous-shot-hole-borer">national biosecurity response led by WA</a> has allocated A$41 million to eradicate the borer. This funding was based on an assessment of what it should cost. But there is only a short window of opportunity to effectively deploy these resources to achieve eradication.</p>
<p>The response includes trapping and surveillance to determine the spread of the pest. More than <a href="https://www.wa.gov.au/government/media-statements/Cook-Labor-Government/Vital-biosecurity-response-to-stop-invasive-beetle-pest-20240130">1.5 million trees on more than 50,000 properties</a> have been inspected and some 3,000 traps laid. </p>
<p>These traps catch flying beetles, which fly just once in their lives, so there’s a low catch probability. This makes it hard to detect false negatives, when no beetles are trapped but there are beetles in the area. This can be improved with alternative <a href="https://doi.org/10.7717/peerj.3656">trap designs</a> and <a href="https://doi.org/10.1371/journal.pone.0179416">chemical lures</a>.</p>
<p>When infested trees are found in WA, the response is “<a href="https://www.agric.wa.gov.au/borer">removing infested trees to save healthy trees</a>”. This could mean hundreds of trees at popular public locations such as <a href="https://www.wa.gov.au/government/media-statements/Cook-Labor-Government/Vital-biosecurity-response-to-stop-invasive-beetle-pest-20240130">Perth Zoo, Lake Claremont, Kings Park and Hyde Park</a> will be felled and chipped.</p>
<p>Continuing with the one control method, felling trees, will leave us with fewer trees, particularly if the eradication campaign runs for many years. Reduction of the <a href="https://theconversation.com/does-higher-density-city-development-leave-urban-forests-out-on-a-limb-57106">urban tree canopy</a> <a href="https://theconversation.com/fewer-trees-leave-the-outer-suburbs-out-in-the-heat-33299">could be profound</a>, and <a href="https://www.abc.net.au/news/2023-02-18/perth-tree-canopy-conference/101980438">Perth already has the sparsest urban tree canopy in the nation</a>. </p>
<p>The flow-on consequences could mean even <a href="https://theconversation.com/trees-are-a-citys-air-conditioners-so-why-are-we-pulling-them-out-21890">higher urban temperatures</a> and poorer <a href="https://doi.org/10.3389/fevo.2021.603757">human</a> <a href="https://doi.org/10.1016/j.amepre.2012.09.066">health</a>. </p>
<p>Urban trees are also valued for their beauty, shade and habitat for animals. All these benefits can be assigned a <a href="https://doi.org/10.1016/j.ufug.2017.11.017">significant monetary value, which would be even higher</a> if intrinsic or cultural value could be included.</p>
<h2>Waging war on the shot-hole borer</h2>
<p>Although felling and chipping entire trees is necessary, there are <a href="https://ipm.ucanr.edu/PMG/PESTNOTES/pn74179.html">other effective control methods</a>. Alternatives may include removing and chipping <a href="https://doi.org/10.1007/s12600-017-0598-6">infested branches only</a>, which may be more <a href="http://doi.org/10.3389/finsc.2023.1279547">cost-effective than felling entire trees</a>, to <a href="https://doi.org/10.1016/j.cropro.2020.105136">injecting at-risk but uninfested trees</a>, and <a href="https://doi.org/10.1094/PDIS-10-17-1569-RE">slowing</a> <a href="https://doi.org/10.1093/jee/toy423">infestations in trees</a> or spraying <a href="https://doi.org/10.3390/biom13040656">repellents onto uninfested trees</a>. In California, traps were developed into an <a href="https://www.californiaavocadogrowers.com/sites/default/files/Trapping-Optimization-and-Development-of-attract-and-kill-strategy-for-the-Polyphagous-Shot-Hole-Borer-in-avocado.pdf">attract-and-kill strategy</a> to tackle the borer in avocado orchards.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Polyphagous shot-hole borer trap set by the OC Parks Department and the University of California, in Irvine Regional Park. The large, multi-tiered black trap with a white collection vessel at the bottom is hanging from a metal pole." src="https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=898&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=898&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=898&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1129&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1129&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574807/original/file-20240211-29-aulz4s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1129&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The best trap for the borer, developed in California, is not being used in Perth.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/orange-california-24-feb-2017-polyphagous-1938882280">Steve Cukrov, Shutterstock</a></span>
</figcaption>
</figure>
<p>While a rapid response is crucial for eradication, we need to keep improving on this, using the most effective methods available. Relevant solutions from around the world suggest <a href="https://doi.org/10.1007/s10340-024-01744-7">broader community engagement</a>, beyond Perth, would be beneficial.</p>
<p>It is unclear what has been learned so far from efforts in WA. Is it still <a href="https://doi.org/10.1007/s10530-013-0529-5">feasible to eradicate the pest completely</a>? We need more experts to evaluate and advise on the response as it continues.</p>
<p>Making the right response choices will be crucial. Just consider other threatening invaders such as the <a href="https://www.outbreak.gov.au/current-outbreaks/red-imported-fire-ant">red imported</a> <a href="https://theconversation.com/how-to-know-if-were-winning-the-war-on-australias-fire-ant-invasion-and-what-to-do-if-we-arent-121367">fire ant</a>, the honey bee <a href="https://www.outbreak.gov.au/current-outbreaks/varroa-mite">varroa</a> <a href="https://theconversation.com/australia-has-officially-given-up-on-eradicating-the-varroa-mite-now-what-214002">mite</a>, and <a href="https://www.dcceew.gov.au/environment/invasive-species/diseases-fungi-and-parasites/myrtle-rust">myrtle</a> <a href="https://theconversation.com/myrtle-rust-is-devastating-australian-forests-a-new-high-tech-spray-holds-out-hope-for-native-trees-219411">rust</a>.</p>
<p>As the borer has only been detected in Perth, the window of opportunity is open now. Let’s make sure we have the best plan of attack so we can achieve eradication. </p>
<p>Australians pride themselves on working together to get things done. If we can bring everyone together to rapidly tackle this insect invasion, the whole nation will benefit.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/citizen-scientists-collect-more-nature-data-than-ever-showing-us-where-common-and-threatened-species-live-212372">Citizen scientists collect more nature data than ever, showing us where common and threatened species live</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/222610/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s a horror story unfolding in the west that could sweep across the country. Beware the shot-hole borer, an exotic pest that threatens our tree crops, plantations, urban forests and wild places.Theo Evans, Associate Professor, The University of Western AustraliaBruce Webber, Principal Research Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2219942024-02-07T00:57:14Z2024-02-07T00:57:14ZIf plants can pick fungi to help fight pests and diseases, it opens a door to greener farming and ecosystem recovery<figure><img src="https://images.theconversation.com/files/572983/original/file-20240202-23-znbxmi.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5176%2C3445&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/yellow-and-black-caterpillar-on-green-leaf-wZnNIcbnVfA">ArjunMJ/Unsplash</a></span></figcaption></figure><p>Just beneath your feet, an ancient and silent alliance endures. This alliance between plants and arbuscular mycorrhizal (AM) fungi is one of the oldest biological partnerships on Earth. </p>
<p>Going back almost <a href="https://www.pnas.org/doi/abs/10.1073/pnas.91.25.11841">half-a-billion years</a>, this relationship paved the way for plants to make it onto land. These early plants, simple and without the complex root systems of plants today, forged an alliance with fungi. This alliance has been instrumental to the evolution of plant life and has helped <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.14976">shape our ecosystems</a>.</p>
<p>These fungi grow into roots where the plants supply them with the carbon (as sugar and fat) they need to survive. The fungi extend thin root-like threads called mycelia into the soil to make <a href="https://www.youtube.com/watch?v=PoV7zgbkiuo">expansive networks that can access nutrients</a> beyond the reach of plant roots. </p>
<p>But these hidden microbes do more than just help plants get nutrients. Plants are constantly dealing with insect pests and diseases, and have done for a long time. To deal with this, they <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-ecolsys-102221-045254">evolved sophisticated defences</a>. AM fungi can <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.17781">dramatically enhance these defences</a>. </p>
<p>So could plants be picking their fungal allies based on their ability to enhance defences against pests and diseases? We recently explored this question and <a href="https://doi.org/10.1093/ismejo/wrae007">proposed hypotheses</a> around how this could happen. The answer could have huge implications for making agriculture more sustainable.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572938/original/file-20240201-102989-zuwwq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artist impression of a Devonian landscape.</span>
<span class="attribution"><span class="source">Eduard Riou (1838-1900) from The World Before the Deluge 1872, United States</span></span>
</figcaption>
</figure>
<h2>Harnessing the ancient alliance</h2>
<p>Considering the benefits AM fungi can provide plants, it’s no surprise there has been a lot of interest in using them in environmental management. Studies show AM fungi can have huge benefits for ecosystem restoration by supporting the <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12843">establishment of native plant communities</a>. Their <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.15119">importance to ecosystem function</a> makes it clear mycorrhizal fungi should be <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1002/ppp3.10092">included in conservation efforts</a>.</p>
<p>In agricultural systems, fungi can increase crop growth, nutrient uptake and <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.15570">yields</a>. These benefits have been a major focus for researchers <a href="https://doi.org/10.1007/s00572-004-0307-4">since the 1950s</a>. </p>
<p>While there is ample evidence of the benefits AM fungi can provide for crops, <a href="https://doi.org/10.1038/s41564-023-01520-w">results in the field are inconsistent</a>. There can be a <a href="https://doi.org/10.1111/ele.13353">mismatch</a> between the nutritional needs of the crops and the ability of the fungi that are present or introduced to the soil to meet those needs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=552&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=552&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572932/original/file-20240201-29-hzjgww.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=552&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Contrast image of mycelia of arbuscular mycorrhizal fungi.</span>
<span class="attribution"><span class="source">Image: Loreto Oyarte Galves</span></span>
</figcaption>
</figure>
<h2>Do plants pick their fungal partners for defence?</h2>
<p>Within the roots of a single plant, numerous fungal species can co-exist, forming complex communities. The species that make up these communities may each offer different capabilities – some are better at defence, while others are better at nutrient uptake. The benefit a plant gets from its fungal partners is, in part, <a href="https://nph.onlinelibrary.wiley.com/doi/10.1002/ppp3.10128">determined by which species are present</a> within its roots.</p>
<p>We can apply AM fungi to the soil but this doesn’t mean these fungi will actually partner up with the plant.</p>
<p>So <a href="https://www.cell.com/trends/plant-science/fulltext/S1360-1385(03)00012-8">what determines which fungi gain entry to the roots</a>? Do plants have a say in this? And, if so, how do they choose? These questions have long been on the minds of ecologists and biologists.</p>
<p>At the core of this relationship is a complex exchange system. Plants provide the fungi with carbon they need, and the fungi provide benefits to the plants. </p>
<p>Research has shown a plant will <a href="https://doi.org/10.1126/science.1208473">play favourites</a> (at least in some cases) with the fungi. They will partner up and <a href="https://www.science.org/doi/full/10.1126/science.1208473">give more carbon to the fungi that provide the most nutrients</a>. </p>
<p>Yet there are <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.15308">significant challenges</a> to exploiting these nutritional benefits in agriculture, where large inputs of nutrients are added to the soil. This can limit our ability to use the fungi in this way by removing plant reliance on the fungi for nutrients.</p>
<p>But can we exploit this partnership for plant defences? Globally, insect pests consume <a href="https://www.science.org/doi/full/10.1126/science.aat3466">up to 20% of the major grain crops</a> alone.</p>
<p>Given that we know plants can play favourites, could they select their fungi to boost defence? We have developed <a href="https://doi.org/10.1093/ismejo/wrae007">hypotheses</a> to try to better understand this question, to set the stage for future research.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572929/original/file-20240201-23-hv463l.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Potential defence-based selection of mycorrhizal fungi by plants.</span>
<span class="attribution"><span class="source">Author provided</span></span>
</figcaption>
</figure>
<h2>A complex question with big implications</h2>
<p>There are many complications. When a plant is under attack by pests, <a href="https://www.nature.com/articles/s41467-024-45026-3">this compromises its ability to supply carbon</a> to its fungal allies, as its carbon resources are strained. It is still not known how these changes affect the plant’s “choice” of fungal partners. </p>
<p>We need a better understanding of how such choices happen and how herbivores can interfere with the ability of plants to reward those fungi providing the most benefit.</p>
<p>However, if plants can pick out the fungi that help them fight off pests and diseases, it could change the way we think about nature’s partnerships. It has big implications for farming, conservation and restoring damaged environments. </p>
<figure class="align-center ">
<img alt="A field of lettuce against the evening sky" src="https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=321&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=321&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572947/original/file-20240201-25-i6sxrd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=321&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pests present huge problems for many crops, such as lettuce.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthy-vegetable-field-under-beautiful-sky-2399299853">hitesh 8482/Shutterstock</a></span>
</figcaption>
</figure>
<p>Knowing how plants select fungal allies would pave the way for better-defended crops, reducing the need to apply synthetic pesticides. It would open up exciting possibilities for helping ecosystems recover and thrive. </p>
<p>The possibility that plants can identify and select fungi based on the benefits they derive opens up exciting new frontiers in ecological research. As we explore these underground interactions, we inch closer to harnessing the potential of one of the Earth’s oldest symbioses. It is a reminder of the complex relationships that maintain life on the planet, connections that are as important today as they were 500 million years ago when the first plants reached for the sun above and the fungi below.</p><img src="https://counter.theconversation.com/content/221994/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Frew receives funding from the Australian Research Council and the British Ecological Society.</span></em></p><p class="fine-print"><em><span>Carlos Aguilar-Trigueros receives funding from the Research Council of Finland and the Humboldt Foundation (Germany). </span></em></p><p class="fine-print"><em><span>Jeff Powell receives funding from the Australian Research Council, the NSW Department of Planning and Environment and the Future Food Systems Limited Cooperative Research Centre. </span></em></p><p class="fine-print"><em><span>Stephanie Watts-Fawkes receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Natascha Weinberger does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Despite its 500-million-year history, the plant-fungi alliance holds mysteries that, once unravelled, could revolutionise agriculture and ecosystem management.Adam Frew, Lecturer and ARC DECRA Fellow, Hawkesbury Institute for the Environment, Western Sydney UniversityCarlos Aguilar-Trigueros, Research Fellow, Department of Biological and Environmental Science, University of JyväskyläJeff Powell, Professor and ARC Future Fellow, Hawkesbury Institute for the Environment, Western Sydney UniversityNatascha Weinberger, Postdoctoral Research Fellow, Hawkesbury Institute for the Environment, Western Sydney UniversityStephanie Watts-Fawkes, Research Fellow, Waite Research Institute, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225682024-02-05T13:29:42Z2024-02-05T13:29:42ZAmid growing legalization, cannabis in culture and politics is the focus of this anthropology course<figure><img src="https://images.theconversation.com/files/572920/original/file-20240201-19-efs8pb.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C3456%2C2214&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Laws that govern cannabis use are changing across the nation.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/marijuana-legalization-high-quality-stock-photo-royalty-free-image/1143280562?phrase=cannabis">Darren415 via Getty Images</a></span></figcaption></figure><figure class="align-right ">
<img alt="Text saying: Uncommon Courses, from The Conversation" src="https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em><a href="https://theconversation.com/topics/uncommon-courses-130908">Uncommon Courses</a> is an occasional series from The Conversation U.S. highlighting unconventional approaches to teaching.</em> </p>
<h2>Title of course:</h2>
<p>Anthropology of Cannabis</p>
<h2>What prompted the idea for the course?</h2>
<p>Whenever I taught my medical anthropology course, I noticed that students were most curious about the section of the course that deals with the uses of plants, fungi and other species for a range of medical purposes. Those purposes included healing, psychological well-being, ritual and spiritual awakening, to name a few.</p>
<p>Once Connecticut, the state where I work, legalized recreational cannabis, I decided it was timely to take the plant section from the original course and expand it to a 14-week course of its own. It was also an opportunity to introduce students to the discipline of anthropology through a topic I knew many of them found interesting. I decided to focus on cannabis instead of the entire panoply of plants and other species, since it was the one plant being legalized in the state at that time.</p>
<h2>What does the course explore?</h2>
<p>Throughout the course, we focus on the different cultural and political significance of cannabis in other geographical contexts. We look at the representation of <a href="https://www.northernstandard.com/a-brief-history-of-cannabis-in-art/">cannabis in art</a>, <a href="https://electricliterature.com/7-lesser-known-stoner-novels-with-suggested-weed-pairings/">literature and pop culture</a>, as well as what the <a href="https://www.nccih.nih.gov/health/cannabis-marijuana-and-cannabinoids-what-you-need-to-know#:%7E:text=The%20cannabis%20plant%20contains%20about,on%20a%20person's%20mental%20state">science of cannabis</a> tells us about its <a href="https://doi.org/10.31887/DCNS.2020.22.3/mcrocq">impact on health and well-being</a>.</p>
<p>We also look at the way stigma and racism impact cannabis users and producers in the United States and elsewhere.</p>
<p>We end the course with students writing letters to themselves in which they imagine how the legal and social landscape for cannabis will be in five years, in the U.S. as well as globally. I plan to send them these letters in 2028.</p>
<h2>Why is this course relevant now?</h2>
<p>While cannabis has long been a part of human existence, the legal and political landscape of cannabis production is rapidly changing. Even if they are not cannabis consumers, students will at least become more aware about the role that cannabis plays in today’s society.</p>
<p>Students may want to know how they can participate in the business side of cannabis. Or they may be interested in doing research on the uses and abuses of the plant.</p>
<p>The course also offers students a way to think about the stigma and discrimination faced by cannabis users and how different cultural systems define and treat behaviors that are deemed deviant. </p>
<h2>What’s a critical lesson from the course?</h2>
<p>My main objective is to have students develop an informed understanding of cannabis as a plant and as a cultural fact. I want them to approach the study of cannabis with an open mind and to walk away with a greater understanding of how harmful stigma can be to individuals in any society. I would hope everyone leaves informed and less inclined to stereotype others. </p>
<h2>What materials does the course feature?</h2>
<p>We read passages from <a href="https://facultyprofile.fairfield.edu/?uname=dcrawford">anthropologist David Crawford</a>’s “<a href="https://rowman.com/ISBN/9781498598187/Dealing-with-Privilege-Cannabis-Cocaine-and-the-Economic-Foundations-of-Suburban-Drug-Culture">Dealing with Privilege: Cannabis, Cocaine, and the Economic Foundations of Surburban Drug Culture</a>,” which challenges the stereotypes that many white people and politicians hold about drug dealing and also explores how drugs became raced and classed entities.</p>
<p>We also read “<a href="https://doi.org/10.1089/can.2022.0251">Understanding and Rebalancing: A Rapid Scoping Review of Cannabis Research Among Indigenous People</a>,” which gives students an opportunity to learn more about Indigenous peoples and cultures alongside learning more about the cannabis plant itself.</p>
<p>And we watch “<a href="https://www.imdb.com/title/tt0028346/">Reefer Madness</a>,” a 1936 film meant to be a cautionary tale about the presumed dangers of marijuana use.</p>
<h2>What will the course prepare students to do?</h2>
<p>Students leave the class better informed about cannabis as a plant and with a better appreciation for the complexity of “drugs” in society. I believe the class also helps students to become more informed citizens, since the laws that govern the use and research on cannabis and other related plants are as much a <a href="https://doi.org/10.1177/0091450919827605">political issue as they are social</a>.</p><img src="https://counter.theconversation.com/content/222568/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hillary Jeanne Haldane does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Students are invited to imagine how the social, political and legal landscape for cannabis will look in the future.Hillary Jeanne Haldane, Professor of Anthropology, Quinnipiac UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2186902024-01-10T13:28:35Z2024-01-10T13:28:35ZCannabis products may harbor fungal toxins harmful to human health, but regulations are uneven or nonexistent<figure><img src="https://images.theconversation.com/files/566948/original/file-20231220-27-jnbdub.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2175%2C1377&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The potential health benefits of cannabis are appreciable only when its products are safe to consume.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/close-up-view-of-the-cannabis-plant-on-black-royalty-free-image/1674390206">Krit of Studio OMG/Moment via Getty Images</a></span></figcaption></figure><p>Hemp and cannabis <a href="https://doi.org/10.3389/fpls.2019.01120">host many fungi</a> inside and outside the plant, most of which are harmless to most people. However, certain types of fungi such as <em>Aspergillus</em> and <em>Fusarium</em> pose <a href="https://doi.org/10.3389/fmicb.2023.1278189">potential health concerns</a>, particularly for the immunocompromised, both through direct infection and consumption of the toxins they produce.</p>
<p>There are currently <a href="https://doi.org/10.1289%2FEHP11206">no state or national testing mandates</a> for <em>Fusasrium</em> toxins in cannabis, and regulations vary greatly for <em>Aspergillus</em> toxins. To better understand the effects of these fungi and their toxins on human health and disease, <a href="https://faculty.utk.edu/Kimberly.Gwinn/about">I assembled</a> a research team of plant pathologists and toxicologists to conduct a <a href="https://doi.org/10.3389/fmicb.2023.1278189">review of the scientific literature</a> on fungal contaminants in cannabis. </p>
<p>We found that the toxins these fungi produce can make it through the manufacturing process and remain present in many cannabis products.</p>
<h2>Fungal toxins in hemp and cannabis</h2>
<p>The <a href="https://www.usda.gov/farmbill">2018 U.S. Farm Bill</a> defined hemp as any part of the plant <em>Cannabis sativa</em> with levels of <a href="https://theconversation.com/cbd-marijuana-and-hemp-what-is-the-difference-among-these-cannabis-products-and-which-are-legal-154256">THC at or below 0.3%</a>. THC is the primary component of <em>Cannabis sativa</em> that has psychoactive effects. Parts with higher levels of THC are considered marijuana. </p>
<p>Medical use of cannabis has been <a href="https://www.ncsl.org/civil-and-criminal-justice/cannabis-overview">approved in most U.S. states and many countries</a>. To provide the maximum <a href="https://theconversation.com/cannabis-derived-products-like-delta-8-thc-and-delta-10-thc-have-flooded-the-us-market-two-immunologists-explain-the-medicinal-benefits-and-potential-risks-204171">potential health benefits</a> associated with cannabis consumption, such as pain relief, plants need to be free of fungal toxins that can cause harm. However, scientists have found fungal toxin levels in <a href="https://bpb-us-e1.wpmucdn.com/blogs.cornell.edu/dist/a/7491/files/2019/08/2019-Hemp-Diseases-Field-Day-Handout8.9.19.pdf">hemp flowers</a> and <a href="https://doi.org/10.3390/toxins12020114">certain cannabis products</a> that exceed acceptable regulatory levels for other food crops.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of the conidial head of Aspergillus, reminiscent of a fleshy daisy" src="https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566938/original/file-20231220-23-l56u28.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The conidial head, or fungal spore, of <em>Aspergillus</em>.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/9fuc1N">Nadeem Zafar/Dr. Yale Rosen Atlas of Pulmonary Pathology via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="https://www.cdc.gov/fungal/diseases/aspergillosis/index.html">Aspergillosis</a>, a lung infection caused by the fungus <em>Aspergillus</em>, is the most potentially harmful fungal infection associated with cannabis consumption. However, our research team determined that <em>Fusarium</em> toxins in cannabis <a href="https://doi.org/10.3389/fmicb.2023.1278189">potentially pose a greater risk</a> to human and animal health than <em>Aspergillus</em>. Researchers have isolated <a href="https://doi.org/10.3389/fagro.2021.796062">16 species of <em>Fusarium</em></a> in cannabis flowers. Many produce toxins that <a href="https://doi.org/10.3389/fmicb.2023.1278189">negatively affect humans and animals</a>, including by causing nausea, vomiting, diarrhea, cancer, reproductive disruption and kidney impairment. </p>
<p>These toxins can also <a href="https://doi.org/10.3390/ijms222212269">worsen disease</a> among those with immune disorders. A 2016 survey of 225 organ transplant professionals found that <a href="https://doi.org/10.1111/ctr.13456">43% reported cases</a> of fungal infections associated with marijuana use among their patients who may be immunocompromised. </p>
<h2>Addressing fungal toxins in cannabis</h2>
<p>The extent of fungal toxins in cannabis and hemp products is still unknown because these toxins are rarely regulated. </p>
<p>Testing for <em>Aspergillus</em> in cannabis <a href="https://doi.org/10.1289/EHP11206">varies by state</a>, and acceptable toxin levels range from zero tolerance to no action. Many states <a href="https://doi.org/10.1093%2Fjaoacint%2Fqsac114">rely on methods</a> that don’t distinguish between fungi that are or aren’t harmful and do not regulate individual pathogens.</p>
<p>Although <em>Fusarium</em> toxins are not regulated in hemp or cannabis, they are <a href="https://www.fda.gov/food/natural-toxins-food/mycotoxins">monitored in major food crops</a> such as corn and wheat because of the <a href="https://theconversation.com/pancakes-wont-turn-you-into-a-zombie-as-in-hbos-the-last-of-us-but-fungi-in-flour-have-been-making-people-sick-for-a-long-time-200428">severe symptoms</a> they can cause in people and animals.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person in protective wear examining hemp plants." src="https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566940/original/file-20231220-23-watzvo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fungal toxin regulation in cannabis is inconsistent across states.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/planting-cannabis-scientist-checking-hemp-plants-royalty-free-image/1298557699">Visoot Uthairam/Moment via Getty Images</a></span>
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<p>Controlling fungi in crops is essential for both plant and human health. Because hemp cultivation was until recently restricted by law, and no state or federal research funds were available, disease management strategies <a href="https://doi.org/10.3389/fmicb.2023.1278189">remain ill-defined</a>. </p>
<p>Although using resistant cultivars for plant production is a safe, economical and environmentally friendly method to control plant diseases, how cannabis develops resistance against pathogens <a href="https://doi.org/10.3390/plants12152764">remains poorly understood</a>. </p>
<p>In states where cannabis cultivation is legal, producers must rely on agricultural products approved for hemp. However, few are registered for use on hemp. Although radiation kills fungi and prevents infection in people, this technique is <a href="https://doi.org/10.3389/fmicb.2023.1278189">not universally applied</a> and there are currently no methods for <a href="https://doi.org/10.3389/fmicb.2023.1278189">removing mycotoxins from cannabis or hemp</a>.</p>
<p>Before producers, consumers and health practitioners can be assured that cannabis products are safe, filling these knowledge gaps is necessary. Additional research on cannabis pathogens and fungal toxins are also needed, as well as better and more consistent methods to regulate medicinal cannabis.</p><img src="https://counter.theconversation.com/content/218690/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kimberly D. Gwinn does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Hemp flowers and certain cannabis products contain fungal toxins, including Aspergillus and Fusarium, that can exceed acceptable regulatory levels.Kimberly D. Gwinn, Professor of Entomology and Plant Pathology, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2195442023-12-12T15:59:00Z2023-12-12T15:59:00ZThrush: zinc may prevent yeast infections – new research<figure><img src="https://images.theconversation.com/files/565180/original/file-20231212-15-6dcsbr.jpg?ixlib=rb-1.1.0&rect=32%2C10%2C7156%2C4031&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The majority of yeast infections are caused by _Candida albicans_.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/candida-fungi-albicans-c-auris-other-1810949326">Kateryna Kon/ Shutterstock</a></span></figcaption></figure><p>Around half a billion women experience a vaginal yeast infection (thrush) every year – with around 140 million women suffering from multiple infections <a href="https://gaffi.org/wp-content/uploads/Denning-Recurrent-VVC-global-burden-Lancet-Infect-Dis-2018.pdf">throughout their lifetime</a>. </p>
<p>While treatments do exist for thrush, for many women these aren’t effective (or they only have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10455317/">short-term effects</a>). But new research has discovered that zinc could be used to <a href="https://www.science.org/doi/10.1126/scitranslmed.adi3363">treat vaginal yeast infections</a> by limiting how the fungus grows in the vagina.</p>
<p>The majority of vaginal yeast infections are caused by the fungus <a href="https://pubmed.ncbi.nlm.nih.gov/26690853/"><em>Candida albicans</em></a>. For most of us, this fungus exists as a normal part of our microbiome and is harmless. But when the microbiome is disturbed (for example, as a result of <a href="https://pubmed.ncbi.nlm.nih.gov/35568028/">antibiotic use</a>), this can change how <em>C. albicans</em> grows – making it more likely to cause an infection.</p>
<p>This fungus has also evolved strategies to help it acquire the nutrients it needs to grow, even in the harsh environments of mammalian tissues. In the human vagina, for example, the fungus finds itself in an environment that’s acidic, with lots of competition from local bacteria for nutrients. </p>
<p>One <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2017.02238/full">key nutrient</a> this fungus needs to grow and multiply is the metal zinc. When <em>C. albicans</em> cannot find zinc in its immediate surroundings, it instead makes a protein called Pra1 that helps it find the metal in nearby cells and the vaginal mucus. This was one of the key findings of this latest study.</p>
<p>The researchers also found that in women who had a vaginal yeast infection caused by <em>C. albicans</em>, the levels of inflammation in the vagina were higher than in women who did not have thrush. This meant their immune system was activated against the fungi.</p>
<p>These inflammation levels also positively correlated with the amount of Pra1 produced. This is important, because inflammation causes many of the <a href="https://www.cdc.gov/fungal/diseases/candidiasis/genital/index.html">symptoms of thrush</a> – including itching, a burning feeling and swelling. </p>
<p>Since Pra1, rather than <em>C. albicans</em> itself, appeared to be causing many of the symptoms of thrush, the researchers then wondered whether adding zinc back into the vagina would stop the fungus making Pra1 and thus reduce inflammation. </p>
<p>They gave a commercially available vaginal gel that contains zinc (currently used for vaginal dryness) to six women who had experienced multiple yeast infections. The women self-applied the gel every night for two weeks, followed by twice a week thereafter for up to three months.</p>
<figure class="align-center ">
<img alt="A woman suffering with an uncomfortable yeast infection." src="https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565183/original/file-20231212-30-neishp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Pra1 protein appeared to be causing many of the uncomfortable thrush symptoms.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vaginal-urinary-incontinence-pain-asian-young-2167998705">Kmpzzz/ Shutterstock</a></span>
</figcaption>
</figure>
<p>The results showed that the zinc-containing gel stopped the symptoms of thrush in five of the six women. While this still needs to be tested in a bigger group, the results are promising – and may provide a new way to treat vaginal yeast infections, particularly for recurrent sufferers.</p>
<p>Exactly how the zinc gel works to stop yeast infections needs to be figured out. But it’s likely because providing the fungus with enough zinc stops it producing Pra1. This in turn reduces inflammation – and symptoms.</p>
<p>So instead of getting rid of the fungus, the gel may be helping the fungus to grow alongside the other microbes that make up the vaginal microbiome in a more balanced, harmonious way. </p>
<h2>Heavy metals</h2>
<p>Many fungi that cause infections in humans make proteins to help them grow when nutrients, such as zinc or copper, are in short supply. Pra1 is one example. </p>
<p>Another is the fungus <em>Cryptococcus neoformans</em>, which causes meningitis in people with Aids. This fungus makes a protein called Ctr4, which helps it grow even when copper levels are limited. Our <a href="https://www.nature.com/articles/s41467-023-43061-0">recent work</a> also showed that <em>C. neoformans</em> will hide inside the brain’s immune cells in order to find copper, helping to promote infection. </p>
<p>But when we deleted Ctr4 from the fungus’s genes, this limited how much the fungus was able to grow – helping to <a href="https://www.nature.com/articles/ncomms6550">prevent brain infection</a>.</p>
<p>Zinc and copper are not only important for how fungi grow – they’re also important <a href="https://pubmed.ncbi.nlm.nih.gov/37905492/">metals that help our immune system</a>. Zinc can fuel the killer functions of neutrophils, a type of immune cell that detects and destroys bacteria and fungi.</p>
<p>Copper helps maintain the number of immune cells in your blood. It’s also found within <a href="https://pubs.acs.org/doi/10.1021/acs.chemrev.0c00921">anti-microbial peptides</a> – small proteins in your saliva and gut that protect against invading microbes.</p>
<p>Because our immune cells use metals to function, they can be rich sources of these nutrients. Some microbes, such as <em>C. neoformans</em>, may target immune cells to acquire these nutrients, as can bacteria that live inside our immune cells – including <em>Mycobacteria</em>,which causes <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4521620/">tuberculosis</a>. Immune cells will sometimes attempt to limit a microbe’s access to these nutrients to prevent infection, a process known as “<a href="https://www.nature.com/articles/s41579-022-00745-6">nutritional immunity</a>”.</p>
<p>Given the way metals can influence the outcome of infections and immune responses, it’s no wonder there’s growing interest in this aspect of immunology research.</p>
<p>Better understanding how metals can be used to prevent and treat thrush could have a significant benefit for all who suffer from it. Vaginal thrush is one of the most common fungal infections worldwide. It is associated with a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6409199/">high economic cost</a>, due to the amount of drugs needed to treat recurrent infections and loss of productivity due to time off work. Moreover, recurrent thrush causes a <a href="https://link.springer.com/article/10.1186/s12955-016-0470-2">poor quality of life</a> for patients.</p>
<p>Antifungal drug resistance is also a growing problem. The development of drug resistance in the <em>C. albicans</em> fungus can be one reason that <a href="https://pubmed.ncbi.nlm.nih.gov/36866967/">standard treatments don’t work</a> for some women.</p>
<p>Harnessing what we’ve learned from recent studies that have examined how fungi use and acquire nutrients to cause infection can help us identify new strategies to treat not only thrush, but other fungal infections which are a growing problem <a href="https://www.who.int/publications/i/item/9789240060241">around the world</a>.</p><img src="https://counter.theconversation.com/content/219544/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca A. Drummond receives funding from the Medical Research Council. </span></em></p>One study found a zinc-containing gel stopped symptoms of thrush in the majority of women.Rebecca A. Drummond, Associate Professor, Immunology and Immunotherapy, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2184072023-12-05T12:39:03Z2023-12-05T12:39:03ZChristmas tree syndrome: why the festive evergreen can make your nose run – and what you can do about it<figure><img src="https://images.theconversation.com/files/563330/original/file-20231204-29-cia24o.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5760%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">These health issues are trigged by the allergens that normally reside in live Christmas trees.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/ruined-christmas-holidays-young-handsome-man-2221562955">voronaman/ Shutterstock</a></span></figcaption></figure><p>Decorating the Christmas tree is a beloved tradition for many of us during the festive season. While some people prefer using and reusing an artificial tree as an environmentally friendly way to enjoy the holiday spirit, others hunt instead for the perfect real tree to adorn with ornaments and cluster presents around.</p>
<p>But some people who decide to get a real tree may find that after it has been decorated they begin to experience cold-like symptoms. While many may simply chalk these symptoms up to having caught a cold – or even COVID – the culprit may actually be a little-known condition called <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">Christmas tree syndrome</a>. </p>
<p>Christmas tree syndrome encompasses a spectrum of health issues triggered by exposure to the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">allergens residing on live Christmas trees</a>. For those who are sensitive to allergens, prolonged exposure to live Christmas trees can lead to <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780128045435000075">respiratory</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930903/">skin health issues</a>.</p>
<p>The <a href="https://www.thermofisher.com/allergy/gb/en/living-with-allergies/understanding-allergies/is-christmas-tree-allergy-making-you-sick.html">main symptoms</a> of Christmas tree syndrome include a stuffy or runny nose, sneezing, irritated eyes, coughing, wheezing and itchy throat. Asthma symptoms may also worsen. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0105-1873.2005.00495.x">Skin-related symptoms</a> may include redness, swelling, and itching.</p>
<p>This phenomenon happens thanks to the ecology of live trees, which carry microscopic entities – including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">pollen and fungi</a>. Pollen, a notorious outdoor allergen, may hitch a ride into our homes, while fungi find a cosy haven in cold, damp Christmas tree farms and garden centres.</p>
<p>Live Christmas trees can also carry mould. Notably, a single Christmas tree can host more than <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext">50 species of mould</a>, creating a habitat for these tiny yet potentially troublesome organisms. Many of the mould varieties found on trees are those <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext">most likely to trigger allergies</a>, including <em>Aspergillus</em>, <em>Penicillium</em>, and <em>Cladosporium</em>.</p>
<p>Researchers have also <a href="https://www.annallergy.org/article/S1081-1206(11)00160-8/fulltext#back-bib3">closely measured mould counts</a> in rooms containing live Christmas trees. During the first three days the tree is indoors, mould spore counts measure about 800 spores per cubic meter of air. On the fourth day, however, spore counts begin rising – eventually reaching 5,000 spores per cubic meter within two weeks.</p>
<p>Mould grows best in <a href="https://health.uconn.edu/occupational-environmental/wp-content/uploads/sites/25/2015/12/mold_guide.pdf">warm, wet and humid conditions</a>. So when the tree is brought indoors, the warmer climate <a href="https://medcraveonline.com/MOJI/MOJI-02-00045.pdf">significantly increases</a> mould production. </p>
<p>Pine pollen is not a major issue for allergy-sufferers when it comes to Christmas trees. But Christmas trees can come into contact with <a href="https://www.sciencedirect.com/science/article/abs/pii/S0021870730901050">other known allergens</a> while they’re growing, which can then be carried into the house. For example, grass pollen can stick to the sap in a Christmas tree during the spring. Then, when the tree is harvested and brought indoors, the sap dries out, and the trapped pollen particles are released into the air.</p>
<h2>Managing symptoms</h2>
<p>Certain people are at higher risk of experiencing Christmas tree syndrome. People with asthma or chronic obstructive pulmonary syndrome (COPD) may be more sensitive to allergens – and these allergens may also exacerbate symptoms such as coughing and wheezing.</p>
<p>People who suffer from allergies are also at greater risk – with research showing <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1930673/">7% of allergy-sufferers</a> experienced a spike in symptoms when they had a Christmas tree in their home. People with skin issues (such as contact dermatitis and itching) may also find that their symptoms worsen around fresh Christmas trees.</p>
<p>Timely recognition of symptoms is crucial to mitigate the impact of Christmas tree syndrome. So if you do suffer from allergies, here’s what you can do:</p>
<ol>
<li><p><strong>Select your tree carefully:</strong> Opt for varieties with lower allergenic potential. Fir trees, such as Douglas and Fraser, are known for producing fewer allergens compared to <a href="https://www.cabdirect.org/cabdirect/abstract/19700607118">spruce or pine</a>. </p></li>
<li><p><strong>Inspect your tree:</strong> Conduct a <a href="https://www.annallergy.org/article/S1081-1206(10)60670-9/fulltext">meticulous inspection for signs of fungi</a> before bringing the tree indoors. Focus on areas where moisture may accumulate, as damp conditions foster mould growth. The most common mould found on Christmas trees is <em>Aspergillus</em>, which will look black on the surface and usually white-ish or yellow underneath.</p></li>
<li><p><strong>Proper maintenence:</strong> <a href="https://www.entandallergyspecialists.com/uncategorized/can-christmas-trees-cause-allergy-symptoms/">Regularly water live trees</a> to prevent dehydration, as this can lead to mould growth. A well-hydrated tree is also less likely to harbour fungus. And since warm, moist environments increase mould growth, try to keep your house ventilated while it’s up. You might even consider using a dehumidifier to decrease moisture levels in your home.</p></li>
<li><p><strong>Minimise direct contact:</strong> Try to avoid too much direct contact when decorating the tree. Wearing gloves might be one may of reducing the risk of skin-related reactions.</p></li>
<li><p><strong>Go artificial:</strong> Consider artificial trees as a <a href="https://jamanetwork.com/journals/jama/article-abstract/662569">practical alternative</a>. These eliminate the risk of allergens and can be reused – reducing their environmental impact. </p></li>
</ol>
<p>Christmas tree syndrome can be a nuisance. But by considering the science and taking precautions, you can ensure an enjoyable and allergen-free festive season.</p><img src="https://counter.theconversation.com/content/218407/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>People who usually suffer from allergies are most at risk.Samuel J. White, Senior Lecturer in Genetic Immunology, Nottingham Trent UniversityPhilippe B. Wilson, Professor of One Health, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2134602023-11-23T19:02:31Z2023-11-23T19:02:31ZDrug resistance may make common infections like thrush untreatable<p><em>Antimicrobial resistance is <a href="https://www.who.int/news-room/fact-sheets/detail/antimicrobial-resistance">one of the biggest global threats</a> to health, food security and development. This month, The Conversation’s experts <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">explore how we got here and the potential solutions</a>.</em></p>
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<p>We’ve all heard about antibiotic resistance. This happens when bacteria develop strategies to avoid being destroyed by an antibiotic. </p>
<p>The consequences of antibiotic resistance mean an antibiotic previously used to cure bacterial infections no longer works effectively because the bacteria have become resistant to the drug. This means it’s getting harder to cure the infections some bacteria cause.</p>
<p>But unfortunately, it’s only one part of the problem. The same phenomenon is also happening with other causes of infections in humans: fungi, viruses and parasites.</p>
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Read more:
<a href="https://theconversation.com/the-rise-and-fall-of-antibiotics-what-would-a-post-antibiotic-world-look-like-213450">The rise and fall of antibiotics. What would a post-antibiotic world look like?</a>
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<p>“Antimicrobial resistance” means the drugs used to treat diseases caused by microbes (bugs that cause infection) no longer work. This occurs with antibacterial agents used against bacteria, antifungal agents used against fungi, anti-parasitic agents used against parasites and antiviral agents used against viruses.</p>
<p>This means a wide range of previously controllable infections are becoming difficult to treat – and may become untreatable. </p>
<h2>Fighting fungi</h2>
<p>Fungi are responsible for a range of infections in humans. Tinea, ringworm and vulvovaginal candidiasis (thrush) are some of the more familiar and common superficial fungal infections. </p>
<p>There are also life-threatening fungal infections such as aspergillosis, cryptococcosis and invasive fungal bloodstream infections including those caused by <em>Candida albicans</em> and <em>Candida auris</em>. </p>
<p>Fungal resistance to antifungal agents is a problem for several reasons. </p>
<p>First, the range of antifungal agents available to treat fungal infections is limited, especially compared to the range of antibiotics available to treat bacterial infections. There are only four broad families of antifungal agents, with a small number of drugs in each category. Antifungal resistance further restricts already limited options.</p>
<p>Life-threatening fungal infections happen less frequently than life-threatening bacterial infections. But they’re rising in frequency, especially among people whose immune systems are compromised, including by <a href="https://7news.com.au/news/qld/first-heart-transplant-patient-to-die-from-fungal-infection-at-brisbanes-prince-charles-hospital-identified-as-mango-hill-gp-muhammad-hussain-c-12551559">organ transplants</a> and chemotherapy or immunotherapy for cancer. The threat of getting a drug-resistant fungal infection makes all of these health interventions riskier.</p>
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Read more:
<a href="https://theconversation.com/how-do-candida-auris-and-other-fungi-develop-drug-resistance-a-microbiologist-explains-203495">How do _Candida auris_ and other fungi develop drug resistance? A microbiologist explains</a>
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<p>The greatest <a href="https://www.frontiersin.org/articles/10.3389/fimmu.2017.00735/full">burden of serious fungal disease</a> occurs in places with limited health-care resources available for diagnosing and treating the infections. Even if infections are diagnosed and antifungal treatment is available, antifungal resistance reduces the treatment options that will work.</p>
<p>But even in Australia, common fungal infections are impacted by resistance to antifungal agents. Vulvovaginal candidiasis, known as thrush and caused by <em>Candida</em> species and some closely related fungi, is usually reliably treated by a topical antifungal cream, sometimes supplemented with an oral tablet. However, instances of <a href="https://www.theage.com.au/national/victoria/they-can-t-sit-properly-doctors-treat-growing-number-of-women-with-chronic-thrush-20230913-p5e499.html">drug-resistant thrush</a> are increasing, and new treatments are needed.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1584939012753862657"}"></div></p>
<h2>Targeting viruses</h2>
<p>Even <a href="https://theconversation.com/why-are-there-so-many-drugs-to-kill-bacteria-but-so-few-to-tackle-viruses-137480">fewer antivirals</a> are available than antibacterial and antifungal agents. </p>
<p>Most antimicrobial treatments work by exploiting differences between the microbe causing the infection and the host (us) experiencing the infection. Since viruses use our cells to replicate and cause their infection, it’s difficult to find antiviral treatments that selectively target the virus without damaging us. </p>
<p>With so few antiviral drugs available, any resistance that develops to one of them significantly reduces the treatment options available. </p>
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Read more:
<a href="https://theconversation.com/why-are-there-so-many-drugs-to-kill-bacteria-but-so-few-to-tackle-viruses-137480">Why are there so many drugs to kill bacteria, but so few to tackle viruses?</a>
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<p>Take COVID, for example. Two antiviral medicines are in widespread use to treat this viral infection: Paxlovid (containing nirmatrelvir and ritonavir) and Lagevrio (molnupiravir). So far, SARS-CoV-2, the virus that causes COVID, has not developed significant resistance to either of these <a href="https://www.cidrap.umn.edu/covid-19/low-levels-resistance-paxlovid-seen-sars-cov-2-isolates">treatments</a>. </p>
<p>But if SARS-CoV-2 develops resistance to either one of them, it halves the treatment options. Subsequently relying on one would likely lead to its increased use, which may heighten the risk that resistance to the second agent will develop, leaving us with no antiviral agents to treat COVID. </p>
<p>The threat of antimicrobial resistance makes our ability to treat serious COVID infections rather precarious.</p>
<h2>Stopping parasites</h2>
<p>Another group of microbes that cause infections in humans are single-celled microbes such as <em>Plasmodium</em>, <em>Giardia</em>, <em>Leishmania</em>, and <em>Trypanosoma</em>. These microbes are sometimes referred to as parasites, and they are becoming increasingly resistant to the very limited range of anti-parasitic agents used to treat the infections they cause. </p>
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Read more:
<a href="https://theconversation.com/antibiotic-resistance-microbiologists-turn-to-new-technologies-in-the-hunt-for-solutions-podcast-217615">Antibiotic resistance: microbiologists turn to new technologies in the hunt for solutions – podcast</a>
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<p>Several <em>Plasmodium</em> species cause malaria and anti-parasitic drugs have been the cornerstone of malaria treatment for decades. But their usefulness has been significantly reduced by the <a href="https://www.mmv.org/our-work/mmvs-pipeline-antimalarial-drugs/antimalarial-drug-resistance">development of resistance</a>. </p>
<p><em>Giardia</em> parasites cause an infection called giardiasis. This can resolve on its own, but it can also cause severe gastrointestinal symptoms such as diarrhea, nausea, and bloating. These microbes have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6207226/">developed resistance</a> to the main treatments and patients infected with drug-resistant parasites can have protracted, unpleasant infections. </p>
<figure class="align-center ">
<img alt="3D illustration of Giardia lamblia protozoan" src="https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559783/original/file-20231115-19-5oxysw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Giardia</em> parasites (illustrated here) cause giardiasis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/giardia-lamblia-protozoan-causative-agent-giardiasis-1038065005">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Resistance is a natural consequence</h2>
<p>Treating infections influences microbes’ evolutionary processes. Exposure to drugs that stop or kill them pushes microbes to either evolve or die. The exposure to antimicrobial agents provokes the evolutionary process, selecting for microbes that are resistant and can survive the exposure. </p>
<p>The pressure to evolve, provoked by the antimicrobial treatment, is called “selection pressure”. While most microbes will die, a few will evolve in time to overcome the antimicrobial drugs used against them. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-bacteria-actually-become-resistant-to-antibiotics-213451">How do bacteria actually become resistant to antibiotics?</a>
</strong>
</em>
</p>
<hr>
<p>The evolutionary process that leads to the emergence of resistance is inevitable. But some things can be done to minimise this and the problems it brings. </p>
<p>Limiting the use of antimicrobial agents is one approach. This means reserving antimicrobial agents for when their use is known to be necessary, rather than using them “just in case”.</p>
<p>Antimicrobial agents are precious resources, holding at bay many infectious diseases that would otherwise sicken and kill millions. It is imperative we do all we can to preserve the effectiveness of those that remain, and give ourselves more options by working to discover and develop new ones.</p>
<hr>
<p><em>Read the other articles in The Conversation’s series on the dangers of antibiotic resistance <a href="https://theconversation.com/au/topics/the-dangers-of-antibiotic-resistance-146983">here</a>.</em></p><img src="https://counter.theconversation.com/content/213460/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christine Carson receives funding from state and federal funding agencies, and the CUREator program, a national biotechnology incubator delivered by Brandon BioCatalyst. She has a commercial interest in companies developing diagnostic tests and preventing viral infections.</span></em></p>We’ve all heard of antibiotic resistance. The same thing is happening with other causes of infections in humans: fungi, viruses and parasites. This is making thrush and other infections hard to treat.Christine Carson, Senior Research Fellow, School of Medicine, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2041642023-09-10T13:04:13Z2023-09-10T13:04:13ZThe nose knows: How microbiomes and the smells they produce help shape behaviour in bugs, birds, beasts and humans<figure><img src="https://images.theconversation.com/files/547261/original/file-20230908-27-yeuep5.jpg?ixlib=rb-1.1.0&rect=612%2C68%2C4958%2C3759&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The microbiome functions as an 'invisible organ' but it often makes its presence known by emitting sounds and smells.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/the-nose-knows-how-microbiomes-and-the-smells-they-produce-help-shape-behaviour-in-bugs-birds-beasts-and-humans" width="100%" height="400"></iframe>
<p>Microbes are an integral part of most, if not all multi-cellular organisms. In fact, these organisms are the way they are because of the tiny partners they house within and on them. These microbes constitute the microbiome: an “invisible organ” weighing approximately <a href="https://doi.org/10.1007/978-981-10-7684-8">2.5 to three kilograms</a> in an adult human and much more in larger animals.</p>
<p>This unique body part was made visible with the advent of modern molecular imaging technologies. In my book <em><a href="https://www.routledge.com/Microbiomes-and-Their-Functions-Why-Organisms-Need-Microbes/Appanna/p/book/9780367749897">Microbiomes and their Functions</a></em>, I explore how it works in partnership with other visible organs and engages in a variety of physiological functions essential for the development and survival of the hosts. </p>
<p>Microbiomes have been part of all these organisms from the beginning, and have evolved in tandem with them, just as their visible organs have.</p>
<p>The digestive tract, with all its components, is a good example of how organs can be shaped by their microbial inhabitants. The digestive tract has markedly disparate features in a carnivore, an omnivore or a herbivore. Herbivores have the longest digestive tracts and <a href="https://opentextbc.ca/biology/chapter/15-1-digestive-systems/">carnivores have the shortest</a>.</p>
<h2>The microbiome</h2>
<p>The bulk of microbiome is found in the <a href="https://doi.org/10.1007/978-981-10-7684-8_2">digestive tract</a>, where it helps extract nutrients from our diet. The diverse microbes constituting the microbiome not only contribute to optimal digestion, but also help prime our immune system, and produce hormones and neurotransmitters (or their precursors) that have profound influence on our behaviours.</p>
<p>The information-laden molecules generated by the microbiome play a crucial role in the body’s <a href="https://doi.org/10.3389/fimmu.2020.00700">non-verbal communication</a>. These <a href="https://doi.org/10.1038/s41467-020-18871-1">microbiome-derived signals</a> can elicit a range of responses including hunger, satiety (feeling full), mood changes and social behaviour.</p>
<figure class="align-right ">
<img alt="Human silhouette showing the gut-brain connection" src="https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=796&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=796&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=796&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1000&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1000&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547017/original/file-20230907-29-lkr7n3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1000&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The information network between the gut microbiome and the brain is aided by the vagus nerve that connects these two organs.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The information network between the gut microbiome and the brain is aided by the vagus nerve that <a href="https://routledge.pub/Microbiomes-and-Their-Functions">connects these two organs</a>.</p>
<p>Microbes like Lactobacillus and Bifidobacterium residing in the gut secrete neurotransmitters known to influence human behaviour <a href="https://doi.org/10.3390/cimb44040096">such as GABA</a> (gamma-aminobutyric acid), acetylcholine, norepinephrine, oxytocin and indole metabolites. Indole derivatives are obtained when gut microbes metabolize the essential amino-acid, tryptophan.</p>
<p>For instance, the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4449495">neurotransmitter dopamine</a> is considered a “feel good” hormone and is often associated with positive emotions. However, low levels of this molecule may contribute to anxiety. On the other hand, indoles are linked to satiety, resulting in a tendency to eat less, and are associated with weight loss.</p>
<h2>Smelly signals</h2>
<p>Despite its invisible nature, the microbiome often makes its presence known by emitting sounds and smells. The latter can be powerful signals that can influence behaviour.</p>
<p>These smelly signals can, at a distance or at a close range, prompt happiness, enthusiasm, anxiety, attraction, fear or <a href="https://doi.org/10.1007/978-981-10-7684-8">aggression</a>. The microbially-concocted odours are a very important tool in the communication arsenal that most organisms — including humans — rely on to send or receive non-verbal messages.</p>
<p>The human skin is home to a diverse range of microorganisms known to contribute to different odours. Bacteria like Staphylococcus and Corynebacterium lodge in the warm and moist underarm region of the skin where the apocrine glands, a source of chemicals, abound. The resident bacteria use these chemical nutrients to shape <a href="https://asm.org/Articles/2021/December/Microbial-Origins-of-Body-Odor">body odour</a>.</p>
<p>These apocrine glands generally produce odourless compounds. It is microbes that fashion those compounds into smell signatures characteristic of an individual. These odoriferous signals can serve to attract or repel people and modify social behaviours. For instance, the presence of select bacteria is known to process non-smelly steroids into compounds with a characteristic urine odour, not conducive to making friends. </p>
<h2>Chemical signals in animals, birds, plants, fungi</h2>
<p>In other mammals, odoriferous compounds like trimethylamine or pentanoic acid entice mates, while in animals endowed with a scent pouch, they lure prey, defend or mark territories. Some of the <a href="https://doi.org/10.3389/fevo.2017.00143">pungent chemicals</a> are notoriously reputed to keep <a href="https://www.washingtonpost.com/lifestyle/kidspost/whats-that-smell-for-some-animals-their-stink-helps-keep-them-alive/2018/08/13/9058fc62-9678-11e8-810c-5fa705927d54_story.html">predators at bay</a>. </p>
<p>Birds have a special gland that hosts a diverse microbial population, which generates scent-releasing chemicals. These easily transmittable signals are aimed at repelling predators, attracting mates, recognizing kin, promoting parental care and <a href="https://www.nytimes.com/2019/11/10/science/birds-smell-bacteria.html">identifying proprietary nests</a>.</p>
<figure class="align-center ">
<img alt="A man's hand holding a small shovel with a truffle on it, patting his truffle-hunting dog with his other hand" src="https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547027/original/file-20230907-19-ya50zw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Truffles — the highly sought-after edible fungus — recruit select microbes to generate aromatic alcohols that lure small mammals to dig them up, which promotes the dispersal of the truffle’s spores.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>These smelly marks are also key to maintaining the social order of numerous insects. <a href="https://doi.org/10.1186/s40168-018-0588-z">These scents</a> can not only help camouflage the hosts, but can also convert loners to crowd-lovers. For instance, it is a scent that cajoles the solitary <a href="https://doi.org/10.3390/insects11100655">locust</a> into a gregarious lifestyle during the feeding season and triggers an insatiable appetite for vegetation.</p>
<p>Some fungi are known to enlist the fragrance of vapour-like chemicals to assemble their microbiome, which in turn helps the host perform a variety of essential physiological functions.</p>
<p>Truffles — the highly sought-after edible fungus — are renowned for their distinctive smell, but they may be dependent on the microbiome to produce this sweet fragrance. In fact, <a href="https://doi.org/10.1128/aem.01098-15">truffles recruit select microbes</a> to generate aromatic alcohols that lure small mammals to dig them up, which promotes the dispersal of the truffle’s spores.</p>
<p>Plants and algae are also dependent on microbe-derived odour prompts to assist them to survive, and even die and be scavenged. Plants depend on these smell signatures to communicate dangers lurking in their environment and even to fend off insects, birds or <a href="https://doi.org/10.3389/fmicb.2021.772420">other predators</a>.</p>
<p>When some algae bloom beyond control due to environmental conditions, they plot their own demise with the <a href="https://doi.org/10.1201/9781003166481">assistance of microbes</a>. Some of these microbes not only help the algae die, but are also responsible for producing distinctive odours that are detected and decoded as food by birds and fish. The result is a clean-up of the dead algae by feasting birds and fish.</p>
<p>The microbiome and its signature smells are crucial for most organisms, whether human, insect or plant. The silent signals sent by the microbiome are essential communications that influence behaviour, and have evolved to help the host survive and thrive.</p><img src="https://counter.theconversation.com/content/204164/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vasu Appanna receives / has received funding from NATO, NSERC, NOHFC and FEDNOR</span></em></p>The microbiome and its signature smells are crucial for most organisms, whether human, insect or plant. The silent signals sent by the microbiome are essential communications that influence behaviour.Vasu Appanna, Professor, Biochemistry, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2078362023-07-13T11:46:33Z2023-07-13T11:46:33ZFungal infections in the brain aren’t just the stuff of movies – Africa grapples with a deadly epidemic<figure><img src="https://images.theconversation.com/files/532417/original/file-20230616-19-tunqcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The fungus Aspergillus fumigatus. This fungus can cause a number of disorders in people with compromised immune function or other lung diseases.</span> <span class="attribution"><span class="source">Kateryna Kon/Science Photo Library/GettyImages</span></span></figcaption></figure><p>In the 2023 American post-apocalyptic drama television series <a href="https://www.hbo.com/the-last-of-us">The Last of Us</a>, humans are plunged towards extinction as a fungal infection of the brain zombie-fies most of the species. This may seem far-fetched but fungi can, and do, infect human brains.</p>
<p>Fungi are present everywhere in our environment: in the air, in the soil, in decaying plant material, on our skin, and even in the gut as part of our natural flora.</p>
<p>Microscopic, disease-causing fungi can invade various parts of the body, leading to a range of symptoms and health problems. In fact, fungal infections contribute to <a href="https://doi.org/10.3390%2Fjof7050367">about 1.5 million deaths</a> every year. </p>
<p>I am a neurobiologist who has been studying fungal infections of the brain for 10 years. I was part of a team that recently <a href="https://doi.org/10.1111/pim.12953">published a review</a> discussing the emergence, and re-emergence, of fungal infections in Africa, especially in sub-Saharan Africa. We conclude that Africa is suffering from a silent, but costly, epidemic of fungal infections. We found that the emergence of deadly fungal infections in the region is primarily driven by a high burden of HIV infections, lack of access to quality healthcare, and unavailability of effective antifungal drugs.</p>
<h2>What are fungal infections?</h2>
<p>For the greater part of the history of humankind, fungal infections were never a threat to human health. This is mainly because most fungi cannot survive the warm human body temperature of 37°C. However, climate change and other environmental pressures <a href="https://doi.org/10.1016/j.joclim.2022.100156">have led</a> to the emergence of species of fungi that are capable of surviving at human body temperatures. </p>
<p>Even then, our immune systems are quite capable of fighting against fungal infections. For instance, our bodies can create localised acidic environments, limit micronutrient availability and release antimicrobial agents. </p>
<p>However, when the immune system is weakened, fungi are able to evade the body’s defences and avoid detection. They can generate bioactive agents which help them evade or adjust to the host immune response. Some adapt to survive in hostile, low-nutrient and low-oxygen environments. </p>
<p>Immunocompromised people are at risk of developing serious or life-threatening fungal diseases. Africa accounts for <a href="https://www.unaids.org/sites/default/files/media_asset/UNAIDS_FactSheet_en.pdf">67%</a> of the global burden of HIV, and opportunistic fungal diseases <a href="https://doi.org/10.1111/pim.12953">are on the rise</a>.</p>
<h2>Some examples</h2>
<p>One example of opportunistic fungal diseases is <a href="https://www.ncbi.nlm.nih.gov/books/NBK525986/">cryptococcal meningitis</a>, which emerged with the HIV pandemic in the late 1980s. Today, sub-Saharan Africa contributes about <a href="https://doi.org/10.1016/s1473-3099(17)30243-8">73%</a> of all global cases and deaths resulting from the disease. Cryptococcal meningitis is caused by the fungus <em>Cryptococcus neoformans</em>, which is found in soil and bird droppings. Infection by the fungus occurs when someone inhales fungal spores. It first leads to the development of a lung infection and later a fatal brain infection. Cryptococcal meningitis is a leading cause of adult meningitis in sub-Saharan Africa and it’s associated with <a href="https://doi.org/10.1016/S1473-3099(22)00499-6">almost 20%</a> of all AIDS-related deaths. </p>
<p>Effective treatments for cryptococcal meningitis are unaffordable and inaccessible for most affected people. Costs <a href="https://doi.org/10.1093/cid/ciy971">range between</a> US$1,400 and US$2,500 per patient for a full two-week antifungal treatment course. </p>
<p>The development of cheaper drugs has been hindered by a limited understanding of how the fungus causes such extreme damage in the brain. </p>
<p>Another example of an HIV-related opportunistic fungal disease is pneumocystis jirovecii pneumonia. It’s caused by a ubiquitous, airborne fungus <em>Pneumocystis jirovecii</em>, which is passed on from person to person. Pneumocystis hardly causes trouble in people with healthy immune systems, but they act as reservoirs and pass the infection to those with poor immune systems, who may develop serious symptoms including fever, a dry cough and trouble with breathing. Pneumocystis jirovecii pneumonia occurs in <a href="https://doi.org/10.1186/s12879-016-1809-3">15%-20%</a> of HIV patients who present with respiratory problems. </p>
<p>The diagnosis of pneumocystis jiroveci pneumonia is expensive and requires a well-equipped laboratory. In Africa’s poor urban and rural healthcare facilities this will be a challenge. The fungus, <em>P. jirovecii</em>, is also extremely difficult to culture, which limits diagnosis and research. </p>
<h2>Growing burden</h2>
<p>In our review, <a href="https://doi.org/10.1111/pim.12953">we found</a> various factors driving the emergence and reemergence of fungal threats. They include climate change, the spread of immunosuppressive diseases, medical advances such as organ transplants (the immune system is suppressed to minimise rejection), the use of immunosuppressants to manage inflammatory diseases, and the use of antibiotics. </p>
<p>While these factors are not unique to Africa, the burden of fungal diseases and the number of people who succumb to them is much greater. </p>
<p>The COVID pandemic seems to have made the global fungal burden worse. For instance, <a href="https://doi.org/10.1016/j.gr.2021.12.016">recent studies</a> have <a href="https://doi.org/10.4103%2Fijd.ijd_17_22">shown</a> that people who were infected with COVID and have recovered are vulnerable to infection with a fungus called mucormycosis, also known as the black fungus. COVID-induced lung damage, high blood sugar, and the steroids often used to treat it are all predisposing factors to black fungus infection. With a reduced capacity to clear fungal spores and a reduced immune response, thanks to the steroids, the fungus can gain entry and infect the sinuses and facial bones, eventually moving to the brain. </p>
<h2>But don’t we have antifungal drugs?</h2>
<p>Most of the population affected by fungal infections live in rural or poor urban settlements. </p>
<p>With poorly funded and overburdened healthcare systems, many African countries are not well prepared to deal with fungal infections. Additionally, some of the WHO-recommended antifungal drugs – such as flucytosine – are <a href="https://gaffi.org/antifungal-drug-maps/">unavailable</a> in most African countries. Ineffective and even rather toxic drugs are sometimes used instead. </p>
<p>The emergence of drug-resistant fungal strains is also a growing threat. Of great concern is the rise in multi-drug resistant Candida species, <a href="https://doi.org/10.1007/s11908-019-0702-9">azole-resistant Aspergillus</a> species and clinically resistant <a href="https://doi.org/10.1007/978-1-60327-595-8_20">Cryptococcus</a>. </p>
<h2>Management strategies</h2>
<p>Fungal threats are adding pressure to overburdened health systems with a limited arsenal of treatment options. </p>
<p>Healthcare professionals, scientific researchers, policymakers and governments must address the gaps in the diagnosis and management of fungal infections. This will help to improve capacity to deal with them.</p><img src="https://counter.theconversation.com/content/207836/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rachael Dangarembizi is a scientific researcher in the field of neuroscience and medical mycology and her research is funded by several funding bodies including the Gabriel Foundation and the UK Medical Research Council. </span></em></p>Africa is suffering from a silent, but costly, epidemic of fungal infections.Rachael Dangarembizi, Neuroinfections Researcher, Neuroscience Institute, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2091422023-07-12T20:03:50Z2023-07-12T20:03:50ZFungi could be the next frontier in fire safety<figure><img src="https://images.theconversation.com/files/536957/original/file-20230712-21-of56i6.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C5422%2C3571&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Australia is no stranger to fire-related disasters. The country <a href="https://www.sciencedirect.com/science/article/pii/S221133552200167X">experiences more than</a> 17,000 residential fires each year.</p>
<p>Each winter brings an increase in potential fire hazards due to the use of heaters and candles. Couple this with our already fire-prone vegetation, and a generally hot and dry climate, and you can see why there’s an urgent need to develop effective and sustainable fireproofing methods.</p>
<p>This is what inspired our research team to <a href="https://www.nature.com/articles/s41598-022-19458-0?fbclid=IwAR3wYYY-fml-OasZVHARLKbi4wjJKCXwNDZ9kaT7n-o7o3yL6Xy61fiQU9Y">create fireproofing materials</a> made from edible fungi. These materials can withstand flames to protect the integrity of a building’s structure (and any occupants).</p>
<p>Our work presents an exciting opportunity for an industry that has spent too long using materials that are harmful to human health and the environment.</p>
<h2>Fireproofing through the decades</h2>
<p>In the 1970s, construction companies in Australia widely used chemicals categorised as “<a href="https://www.niehs.nih.gov/health/topics/agents/flame_retardants/">halogenated flame retardants</a>” to fireproof buildings, furnishings and electronics.</p>
<p>These flame retardants, which <a href="https://ntp.niehs.nih.gov/whatwestudy/assessments/cancer/ongoing/hfr#:%7E:text=Halogenated%20flame%20retardants%20encompass%20a,%2C%20structural%2C%20and%20chemical%20properties">largely consist</a> of bromide or chlorine-containing chemicals, are effective in interrupting combustion. But many have been associated with <a href="https://pubmed.ncbi.nlm.nih.gov/21268442/">adverse health effects</a> including immunotoxicity, reproductive toxicity, cancer and impaired neurological function. </p>
<p>Phosphorus and nitrogen-based flame retardants are preferred over their halogenated counterparts and are still used for fireproofing today, including in Australia. However, these too pose some risk to human health and to nature (through toxicity and accumulation in the environment).</p>
<h2>Exploring a better alternative</h2>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0141391023001714?dgcid=coauthor">Our team has</a> produced a material made entirely out of mycelium, which shows great promise for fireproofing. </p>
<p>Mycelium is the root-like structure of fungi. It’s made up of many thin, branched filaments. The cell walls of these filaments are largely composed of a natural polymer called chitin (which you can also find in <a href="https://theconversation.com/5-ways-fungi-could-change-the-world-from-cleaning-water-to-breaking-down-plastics-157320">crab shells and insect exoskeletons</a>). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536955/original/file-20230712-17-pcvo4b.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mycleium is the vegetative root-like structure of fungi. It’s usually hidden from view underground.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Our mycelium-based material is lightweight, eco-friendly, biodegradable and has a relatively long ignition time.</p>
<p>When exposed to intense fire or heat, the material can transform to char – a black high-carbon residue that remains when all the water and volatile compounds have burned off. This is similar to the charcoal that remains when wood is burned. This char protects any underlying flammable material by slowing down heat transfer and preventing further combustion. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=222&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=222&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=222&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=279&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=279&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535988/original/file-20230706-25-vu83ie.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=279&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Our mycelium material can be used as a thin, wallpaper-like fireproofing layer.</span>
</figcaption>
</figure>
<p>Unlike current fireproofing materials, our material releases only harmless natural products when exposed to fire, such as water and carbon dioxide.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/scientists-create-new-building-material-out-of-fungus-rice-and-glass-98153">Scientists create new building material out of fungus, rice and glass</a>
</strong>
</em>
</p>
<hr>
<h2>A versatile material</h2>
<p>Our material is flexible and can be manipulated to varying thinness, including down to a <a href="https://www.sciencedirect.com/science/article/pii/S0141391023001076">1mm thin wallpaper</a>. This makes it more useful than the bulky fungal <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/fam.2637">bricks</a> our group previously created. </p>
<p>It could be used as thin wallpaper-like sheets, or consolidated into thicker and stronger core materials that resemble timber or cladding.</p>
<p>We showcase two possible applications for the building and construction industry (although there would be other uses in industries such as automotive and aerospace engineering):</p>
<ol>
<li><p>fungal-only sheets as laminates, where the thickness can be customised, which would be ideal for use as insulation panels</p></li>
<li><p>fungal layers attached to the surface of flammable structures, in the same way wallpaper is applied to walls, to enhance fire protection.</p></li>
</ol>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535990/original/file-20230706-26-g3zktn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=573&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The material could be used as a consolidated laminate with a thickness of about 4.5mm.</span>
</figcaption>
</figure>
<h2>The next steps</h2>
<p>Although mycelium-based materials are currently used globally for construction, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8934219/">packaging and insulation</a>, none are so far commercially available. Moreover, none have been used or approved for fireproofing.</p>
<p>We’ve been approached by the mushroom industry to develop our material and its feasibility for commercialisation. Collaboration will be crucial to creating a closed-loop industry where agricultural waste can be up-cycled into sustainable biomaterials that meet fire safety needs. </p>
<p>There’s a long way to go before our product can be bought off-the-shelf, and we’ll need to address various large-scale manufacturing challenges in the process.</p>
<p>Nonetheless, we hope our work can eventually contribute to a future where building fires are significantly reduced, and where our homes are safer and more sustainable spaces to live in.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/5-ways-fungi-could-change-the-world-from-cleaning-water-to-breaking-down-plastics-157320">5 ways fungi could change the world, from cleaning water to breaking down plastics</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/209142/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Everson Kandare receives funding from the Australian Research Council, Sustainability Victoria, Tyre Stewardship Australia, and Coorperative Research Centres.</span></em></p><p class="fine-print"><em><span>Nattanan Chulikavit receives funding from Australian Research Council. </span></em></p><p class="fine-print"><em><span>Tien Huynh does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>For decades, construction companies have used fireproofing chemicals associated with risks to human health and the environment. We need safer alternatives.Tien Huynh, Associate Professor, School of Sciences, RMIT UniversityEverson Kandare, Associate Professor, School of Engineering, RMIT UniversityNattanan Chulikavit, PhD student, School of Engineering, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2077372023-06-26T20:05:49Z2023-06-26T20:05:49ZWhat do the different colours of mould mean in my house?<figure><img src="https://images.theconversation.com/files/533888/original/file-20230626-29-3zt1z7.jpg?ixlib=rb-1.1.0&rect=23%2C62%2C4656%2C3205&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/jDRd_WHGFAI">Sandy Millar/Unsplash</a></span></figcaption></figure><p>You may be interested (or possibly horrified) to discover you ingest and inhale thousands of tiny life forms on a daily basis.</p>
<p>The air and surfaces around you are home to multitudes of <a href="https://www.sciencedirect.com/science/article/abs/pii/B978012394805200004X">bacteria, fungi, viruses</a>, mites, algae and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0043135400004206">protozoa</a>. Your skin isn’t much better, with a complex ecosystem of organisms called commensals which aren’t necessarily good or bad, but will shift in their composition depending on <a href="https://www.nature.com/articles/nature11053">where you live</a>, <a href="https://www.mdpi.com/2079-9284/6/1/2">the products you use</a> and <a href="https://elifesciences.org/articles/458">the pets you have</a>. </p>
<p>Most of these creatures are generally undetectable due to their microscopic size and low concentrations. But when they find a niche they can exploit, you might notice them by their smell, or the appearance of unwanted staining and colour changes. A lot of this fungal growth is what we call mould.</p>
<p>We’ve all been disappointed in ourselves at one time or another, lifting a neglected orange out of the fruit bowl to discover the bottom half is covered in a velvety blue-green growth.</p>
<p>But what do the myriad colours that appear on our stuff tell us about the world we try not to think about?</p>
<h2>Black</h2>
<p>Often black staining is quite a disturbing occurrence. The concept of toxic black mould is one many people have become aware of due to <a href="https://theconversation.com/fungi-after-the-floods-how-to-get-rid-of-mould-to-protect-your-health-111341">flood impacts</a>.</p>
<p>A quick online search will likely terrify you, but not all black discolouration is due to the same organisms, and almost none of it will outright cause you harm.</p>
<p><em>Stachybotrys</em> is the one known as toxic black mould. It often turns up on <a href="https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.99107s3505">building materials that have been wet for a long time</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A severely mouldy wall covered in grey and black blotches" src="https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=384&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=384&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=384&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=483&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=483&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533907/original/file-20230626-67275-zxd3ah.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=483&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Toxic black mould can develop in the home due to a flood or chronic damp conditions.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/water-damage-causing-mold-growth-on-547425403">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-does-household-mould-affect-your-health-48341">Health Check: how does household mould affect your health?</a>
</strong>
</em>
</p>
<hr>
<p>When the grout in your shower turns black though, that’s a different fungus called <em><a href="https://www.ajol.info/index.php/ajb/article/view/130453">Aureobasidium</a></em>. It’s slimy, sticky and somewhere between a filamentous mould, which grows threadlike roots through whatever it’s eating, and a yeast, which prefer a free-floating, single-celled style of life. </p>
<p>Bleaching will often kill <em>Aureobasidium</em>, but the dark pigmentation will likely hang around – harmlessly, but stubbornly.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up of white grout between grey tiles with black spots on it" src="https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533894/original/file-20230626-19-68wsem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The mould colonising the grout in your shower is unlikely to be toxic. In fact, you can kill it with bleach, but the harmless pigment may linger behind.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/black-green-mold-growing-on-shower-1999288574">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Blue</h2>
<p>That blue orange I mentioned before, you can thank <em>Penicillium</em> for that. The organism that <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168160512000852">gives us blue cheese</a> and the antibiotic penicillin is also responsible for producing a dense growth of mould that almost looks like smoke when disturbed, spreading millions of spores onto the rest of your fruit bowl.</p>
<p><em>Penicillium</em> is a big group with <a href="https://www.sciencedirect.com/science/article/pii/S0166061620300129">hundreds of species</a>, ranging from recognised pathogens to species yet to be named. However, the ones that turn up in our homes are generally the same “weed” species that simply cause food spoilage or grow in soil. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a bright orange with a fuzzy blue mould spot on it" src="https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533895/original/file-20230626-107392-7jinnz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mould growing in your fruit bowl is related to the one that gave us penicillin. The dusty appearance are spores waiting to be disturbed and spread all over your other fruit.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/moldy-orange-fruit-close-rotten-concept-2131666769">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Yellow and orange</h2>
<p>We often think of fungi as organisms that thrive in the dark, but that’s not always true. In fact, some need exposure to light – and ultraviolet (UV) light in particular – to complete their life cycle.</p>
<p>Many plant pathogens use UV light exposure as a trigger to produce their spores, and then protect their DNA by <a href="https://link.springer.com/article/10.1134/S0003683814020094">hiding it behind melanin-containing shells</a>.</p>
<p><em>Stemphylium</em> and <em>Epicoccum</em> turn up in our homes from time to time, often hitching a ride on natural fibres such as jute, hemp and hessian. They produce a spectrum of staining that can often turn damp items yellow, brown or orange. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A piece of wood laminate with yellow patches on it" src="https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533948/original/file-20230626-15121-eh3869.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Yellow moulds can leave a stain behind even once the spores are gone.</span>
<span class="attribution"><span class="source">Michael Taylor</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Green</h2>
<p>We’re all fairly familiar with the green spots that turn up on mouldy bread, cake and other food items. Often we try to convince ourselves if we just cut off the bad bit, we can still salvage lunch.</p>
<p>Sadly that’s not the case, as the roots of the fungi – collectively called mycelium – spread through the food, digesting and collecting sufficient nutrients to pop out a series of tiny fruiting bodies which produce the coloured spores you see.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-is-it-safe-to-cut-mould-off-food-21382">Health Check: is it safe to cut mould off food?</a>
</strong>
</em>
</p>
<hr>
<p>The green tuft is often from a group of fungi called <em>Aspergillus</em>. Under the microscope they look rather like the puffy top of a dandelion gone to seed.</p>
<p>Like <em>Penicillium</em>, <em>Aspergillus</em> is another big fungal group with lots of species that turn up virtually in every environment. Some are <a href="https://academic.oup.com/mmy/article/43/Supplement_1/S87/1748298">heat tolerant</a>, some <a href="https://www.tandfonline.com/doi/full/10.1080/21553769.2015.1033653">love acid</a> and some will happily produce spores that <a href="https://www.sciencedirect.com/science/article/abs/pii/S1749461311000406">stay airborne for days to months at a time</a>.</p>
<p>In the green gang is also a fungus called <em>Trichoderma</em>, which is Latin for “hairy skin”. <em>Trichoderma</em> produces masses of forest-green, spherical spores which tend to grow on wet cardboard or dirty carpet. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A pile of green grains on a small round tray" src="https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533897/original/file-20230626-160496-7cuh4q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Trichoderma is present in all soils, and will grow fast if the conditions are right.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/trichoderma-biocontrol-agent-plant-disease-control-670125520">Shutterstock</a></span>
</figcaption>
</figure>
<h2>Pink, purple and red</h2>
<p>There are plenty to speak of in this category. And there is also a common bacterium that makes the list.</p>
<p><em>Neurospora</em>, also known as the red bread mould, is one of the most studied fungi in scientific literature. It’s another common, non-hazardous one that has been used as <a href="https://bsapubs.onlinelibrary.wiley.com/doi/full/10.3732/ajb.1400377">a model organism</a> to observe fungal genetics, evolution and growth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A block of orange mouldy substance sitting on a banana leaf" src="https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533913/original/file-20230626-24-eh3869.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Red oncom, a traditional staple food in West Java, Indonesia, is made with <em>Neurospora</em>.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fresh-raw-red-oncom-vegetarian-food-396059380">Shutterstock</a></span>
</figcaption>
</figure>
<p><em>Fusarium</em> is less common indoors, being <a href="https://www.sciencedirect.com/science/article/pii/S0261219416302794">an important crop pathogen</a>, but will sometimes turn spoiled rice purple. It also occasionally turns up on wet cement sheet, causing splotchy violet patches. <em>Fusarium</em> makes large, sticky, moon-shaped spores that have evolved to spread by rain splashes and hang onto plants. However, it is fairly bad at getting airborne and so doesn’t tend to spread very far from where it’s growing. </p>
<p>Finally in this category, that pink scum that turns up around bathroom taps or in the shower? It’s actually a bacterium called <em>Serratia</em>. It will happily chew up the soap scum residue left over in bathrooms, and has been shown to <a href="https://journals.asm.org/doi/full/10.1128/AEM.02632-10">survive in liquid soaps and handwash</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of white tile grout covered in a pink translucent film" src="https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533900/original/file-20230626-98733-ggql6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some of the pink stuff in your bathroom isn’t even mould – it’s bacteria.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/red-bacteria-serratia-marcescens-growing-on-1694681443">Shutterstock</a></span>
</figcaption>
</figure>
<h2>White</h2>
<p>When fungi were first being classified and were eventually given their own phylogenetic kingdom, there were lots of wonderful and not strictly categorical ways we tried to split them up. One of these was hyaline and non-hyaline, essentially referring to transparent and coloured, respectively.</p>
<p>One of the interesting non-pigmented moulds you may well catch sight of is a thing called <em>Isaria farinosa</em> (“farinosa” being Latin for “floury”). This fungus is a parasite of some moths and cicadas and is visible as brilliant white, <a href="https://www.tandfonline.com/doi/abs/10.1080/09583150802471812">tree-shaped growths on their unfortunate hosts</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dead bug on a green forest floor with white and yellow growths sticking out of it" src="https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533911/original/file-20230626-72187-xubf6k.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A example of <em>Isaria farinosa</em> growing out of its host.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Isaria_farinosa_%28Holmsk.%29_Fr_448940.jpg">Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>So when you notice the world around you changing colour, you can marvel with your newfound knowledge at the microscopic wonders that live complex lives alongside yours. Then maybe clean it up, and give the fruit bowl a wash. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hidden-housemates-meet-the-moulds-growing-in-your-home-54743">Hidden housemates: meet the moulds growing in your home</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/207737/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Taylor consults for WSP Australia in the area of occupational hygiene, indoor environmental quality and hazardous materials. He has previously received grant funding from SafeWork SA to study fungi in indoor environments. </span></em></p>Usually, mould spores are invisible – but give them a niche to exploit and you’ll get all kinds of colours on the things in your home.Michael Taylor, Adjunct academic, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2081562023-06-23T13:39:47Z2023-06-23T13:39:47ZDirty tea towels are breeding grounds for harmful bacteria – here’s how to clean them properly<figure><img src="https://images.theconversation.com/files/533147/original/file-20230621-15-81vklh.jpg?ixlib=rb-1.1.0&rect=123%2C0%2C6227%2C4218&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Yep, when you've finished, both of those need to go in the wash.</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/close-up-of-women-in-pattern-dresses-drying-cutlery-with-tea-towels-6956744/">pexels/karolina grabowska</a></span></figcaption></figure><p><a href="https://link.springer.com/article/10.1023/A:1016378226861">Kitchens</a> can harbour all sorts of germs and bacteria. These can arrive via humans, pets, uncooked food or even plants, meaning that a high proportion of <a href="https://academic.oup.com/jambio/article-abstract/119/2/582/6717307?redirectedFrom=fulltext">foodborne infections</a> are acquired directly within the home. </p>
<p>An important cleaning aid in most kitchens is the tea towel, also known as a dishcloth. Usually made of cotton or linen, they are used to dry wet hands and kitchen implements as well as wiping down surfaces – so play an important role in kitchen hygiene. </p>
<p>But, because hands and uncooked fresh produce are often rich in a diverse variety of germs, tea towels are prone to picking up the bacteria they come into contact with. </p>
<p>Indeed, in a <a href="https://www.semanticscholar.org/paper/Achieving-hygiene-in-the-domestic-kitchen%3A-the-of-Cogan-Slader/ffc798f7219afc6f986d6f18c62e6e496e7e0161">study</a> that used tea towels to wipe down chopping boards that had been used to prepare raw chicken with salmonella (which can cause diarrhoea, fever and stomach cramps), 90% of the cloths became contaminated with salmonella, too.</p>
<p><a href="https://www.tandfonline.com/doi/abs/10.1080/09603129509356839?src=recsys">Several studies</a> have looked at the germs tea towels typically carry in domestic kitchens. One study sampled 100 used tea towels and found a marked presence of <a href="https://www.tandfonline.com/doi/abs/10.1080/09603120050127202?src=recsys">staphylococcus aureus</a> <em>Staphylococcus aureus</em>, which is often found on the skin but is also a pathogen that can cause a variety of issues such as abscesses, joint infections and even pneumonia.</p>
<figure class="align- centre ">
<img alt="Tea towels hanging to dry on the oven door." src="https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533151/original/file-20230621-15-620nos.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dirty tea towels are a breeding ground for bacteria and foodborne illnesses.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-teatowels-on-rack-2293555605"> Joe Kuis/Shutterstock</a></span>
</figcaption>
</figure>
<p>Tea towels are good at picking up germs which is important as another <a href="https://www.tandfonline.com/doi/abs/10.1080/09603129509356839?src=recsys">study of 46 kitchens</a> found a wide range of harmful bacterial species living on kitchen surfaces, which are often cleaned by tea towels. </p>
<p>Surfaces were found to have <em>Enterobacter</em> (which can cause respiratory tract infections, skin infections, urinary tract infections and heart, bone and eye infections), <em>Klebsiella</em> (which has been linked to serious infections of the lungs, bladder, brain and blood), and <em>E. coli</em> (which can cause upset stomachs and urinary tract infections). </p>
<p>Several kitchens also had <em>Pseudomonas aeruginosa</em>, which can cause lung infections. <em>Bacillus subtilis</em>, which can lead to eye infections and abscesses, was also found in more than half of the kitchens sampled. And all of the samples from the kitchens were found to have <em>Staphylococcus</em> and <em>Micrococcus</em>. In people with weak immune systems, <em>Micrococcus</em> has been linked to lung infections, such as pneumonia and septic arthritis along with eye and heart infections.</p>
<p>The levels and types of germs found on these tea towels were influenced by how they were used, how often they were washed and how long they were dried for. <a href="https://www.sciencedirect.com/science/article/pii/S0956713522003887?via%3Dihub">Rinsing tea towels in hot water</a> at 60°C was found to reduce levels of bacteria later spread by contaminated cloths, which is important as infection likelihood is often related to how many bacteria you ingest.</p>
<h2>Clean your cloths</h2>
<p>These studies suggest there is an infection risk from tea towels and that most kitchen cloths may be contaminated with high levels of bacteria. It’s easy, then, for these germs to transfer on to food preparation surfaces, potentially causing serious food poisoning. </p>
<p>The infection risk of using tea towels is well-recognised by the medical profession. Indeed, in UK hospitals, fabric <a href="https://www.leicspart.nhs.uk/wp-content/uploads/2021/02/Food-Hygiene-for-Ward-and-Therapy-kitchens-Infection-Prevention-Policy-exp-Feb-24.pdf">tea towels are not allowed</a>. Instead, patient crockery, cutlery and food preparation work surfaces are cleaned and dried with disposable paper towels. </p>
<p>One of the reasons tea towels act as such good microbial reservoirs is that they are often damp as they are used to absorb moisture and mop up spills. <a href="https://www.sciencedirect.com/science/article/pii/S0956713522003887?via%3Dihub">Water enables germs to grow</a>. And so a moist tea towel left in a warm kitchen provides an ideal environment for bacteria to multiply. This is particularly the case if food traces are present, too. </p>
<p>So what’s the best way to sanitise your used tea towel? Tea towels that are hung up in the air tend to dry faster than cloths stored and squeezed into balls, which can affect levels of bacteria in the towels. </p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0956713522003887?via%3Dihub">Laboratory experiments</a> that involved covering tea towels in salmonella, found that the bacteria multiplied in all types of cloths that were crumpled. But levels of bacteria were reduced by 1,000 times if the tea towels were hung to dry for 24 hours at room temperature. </p>
<h2>Reduce the germs</h2>
<p>To avoid tea towels spreading germs around the kitchen, it’s recommended that the cloths are washed regularly and when they get wet, are allowed to dry completely before being used again. Using <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">disposable cloths</a> or paper towels for heavily contaminated areas, such as those involving raw meat, could also help to stop the spread of bacteria. </p>
<p>In terms of tea towel hygiene, you should clean and thoroughly dry your kitchen towel <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">at least once a day</a> or after each use. The UK government recommends that tea towels should be sanitised by washing them in a washing machine with laundry detergent on a hot wash cycle of 90°C. </p>
<figure class="align-center ">
<img alt="Tea towels drying on a clothesline." src="https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533152/original/file-20230621-18-piu85o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Daily washing of tea towels is crucial for kitchen hygiene.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/colourful-towels-tea-hung-outside-dry-1655802655"> Tony Skerl/Shutterstock</a></span>
</figcaption>
</figure>
<p>Laundry detergents contain hard water softeners, surfactants (which increase the wetting effect of water by reducing its surface tension), detergents, bleaches and digestive enzymes. Food stains on tea towels will probably be a mixture of proteins, fats and carbohydrates, which the enzymes degrade. </p>
<p>And the detergent helps to dissolve the stains, which are released into the washing water. Since proteins and fats are also involved in the attachment of bacteria to surfaces, laundry detergents will help to detach and so reduce bacteria levels in tea towels. </p>
<p>If you <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">wash tea towels</a> by hand, ensure any obvious food and dirt are removed by rinsing in hot water with detergent before disinfection. After washing, you can sanitise any microbes remaining using boiling water or a disinfectant such as bleach, diluted as per the manufacturer’s instructions. </p>
<p>Ironing tea towels on a hot setting will also effectively sanitise as the temperature is <a href="https://www.food.gov.uk/sites/default/files/media/document/cloths.pdf">above 90°C</a>.
You should also store your laundered tea towels in a dry, clean area, away from any uncooked food and grubby hands.</p><img src="https://counter.theconversation.com/content/208156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Primrose Freestone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A microbiologist on the deadly germs lurking in your kitchen and why you need to wash tea towels and dishcloths more often.Primrose Freestone, Senior Lecturer in Clinical Microbiology, University of LeicesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2043822023-06-15T14:00:29Z2023-06-15T14:00:29ZSouth Africa is famous for its biodiversity: a new network will store and manage its plant and animal samples<figure><img src="https://images.theconversation.com/files/522563/original/file-20230424-18-p8d0et.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Biobank samples can be used to support research in a range of disciplines.</span> <span class="attribution"><span class="source">luchschenF/Shutterstock</span></span></figcaption></figure><p><em>South Africa has created a network of facilities to store hundreds of thousands of samples of biological material from plants, animals, bacteria and fungi. The samples are currently held in biobanks in the country. The aim is twofold: to ensure researchers have access to all available samples, and to establish common policies, procedures and standards for biodiversity biobanks. This is important if the country is to keep pace with advances in research.</em> </p>
<p><em>The South African National Biodiversity Institute’s Professor Michelle Hamer, who heads the Biodiversity Biobanks South Africa project, spoke to The Conversation Africa.</em></p>
<h2>What is a biodiversity biobank and what’s stored in it?</h2>
<p>The definition can differ according to context. For the <a href="https://bbsa.org.za/">Biodiversity Biobanks South Africa</a> project it’s defined as a repository of biological material that’s not usually of human origin. </p>
<p>That can include reproductive tissues like seeds, eggs and sperm; other tissues (blood, hair, muscle); DNA and other extracts; and environmental samples such as water or soil that contain biological communities. The materials are often cryopreserved (stored at ultra-low temperatures). Some are stored at low or room temperature.</p>
<p>The materials that now fall under the auspices of Biodiversity Biobanks South Africa represent biological communities, species, strains, varieties and breeds present in South Africa. That includes crops and livestock. The samples can be used to support research in a range of disciplines. They could also help in developing new or improved products and practices in several fields: agriculture, human health and wellness, environmental management and conservation biology.</p>
<h2>What led to the project being launched?</h2>
<p>It’s one of the projects under a <a href="https://www.dst.gov.za/images/Attachments/Department_of_Science_and_Technology_SARIR_2016.pdf">research roadmap</a> initiated by the national Department of Science and Innovation in 2017. The programme aims to develop infrastructure that’s accessible to all researchers. </p>
<p>This infrastructure and the research conducted through biobanks can help to address a number of national challenges like climate change and food security. For instance, work done through the <a href="https://www.arc.agric.za/arc-vopi/Pages/Plant%20Breeding/Genebank%20Collections.aspx">genebanks at the country’s Agricultural Research Council</a> has resulted in new maize cultivars. Some are <a href="https://allianceforscience.org/blog/2016/08/water-efficient-maize-for-africa-by-the-agricultural-research-council-of-south-africa/">drought resistant</a>; others are resistant to the <a href="https://theconversation.com/armyworms-are-wreaking-havoc-in-southern-africa-why-its-a-big-deal-72822">fall armyworm</a>. This helps smallholder farmers to increase production and ensure household food security.</p>
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Read more:
<a href="https://theconversation.com/how-biobanks-can-help-improve-the-integrity-of-scientific-research-100035">How biobanks can help improve the integrity of scientific research</a>
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<p>South Africa is well placed to host biodiversity biobanks because it’s one of 17 <a href="https://www.kids-world-travel-guide.com/megadiverse-countries.html">megadiverse countries</a> (others include Brazil, Mexico, the Democratic Republic of the Congo and Madagascar). Collectively these 17 countries hold more than two thirds of the world’s biodiversity. </p>
<p>They not only have an exceptionally high number of plant, animal and fungi species (<a href="https://www.sanbi.org/biodiversity/science-into-policy-action/biodiversity-information-management/south-african-animal-species-information/">more than 100,000</a> in South Africa), but also a high number or proportion of endemic species – these are only found in the country. </p>
<h2>Why is creating one network so important?</h2>
<p>South Africa has an estimated half a million items in various biobanks. Most of this material has been collected or established over the last 20 to 30 years.</p>
<p>The problem is that the biobanks holding these samples have traditionally operated largely in isolation. There is not an established culture of using biobanks among biodiversity researchers. A researcher will get funding, go into the field and collect material, analyse it and then keep it in a freezer in their laboratory until, too often, it’s thrown out to free up space.</p>
<p>When another researcher is working on the same species, they have to get funding to do this all over again. This could be addressed if samples were deposited in a biobank at the end of a study and made accessible to other researchers. </p>
<p>One of the reasons for this fragmentation is that some researchers don’t trust the system and fear that if they deposit samples in a biobank they will not be able to access these if they need them later, or they are concerned about the quality of samples that may be supplied by biobanks. </p>
<p>There are no currently no common policies, procedures and standards related to biodiversity biobanks in South Africa, which means that the quality of materials cannot always be assured. While there are international guidelines and standards for biobanks in general, implementation is a common challenge globally. </p>
<p>South Africa also has no established training programme for biobank technicians or curators or managers. </p>
<p>The only way to address these challenges is through working as a cohesive network with a common purpose and shared objectives. The Biodiversity Biobanks South Africa is that network. Creating it solves four problems:</p>
<ul>
<li><p>ensures samples aren’t stored in isolation and are accessible </p></li>
<li><p>ensures samples are stored, and not thrown away </p></li>
<li><p>addresses the issue of trust by promoting credible practices in biobanking </p></li>
<li><p>creates a collaborative platform for growing the biobanks so that they hold materials that represent the country’s biodiversity. </p></li>
</ul>
<p>There are currently <a href="https://bbsa.org.za/participation-in-the-bbsa/">seven participating institutions and almost 20 different biobanks</a>. </p>
<h2>What are the benefits?</h2>
<p>If South African scientists are to compete in all areas of research and development, they need access to a range of high quality and well documented biobanked materials.</p>
<p>Take genome sequencing technologies. Genome sequencing involves fragmenting an organism’s DNA, studying the composition or sequence of those pieces, then reconstructing it all into the original sequence.</p>
<p>These technologies are being used for an enormous – and ever increasing – range of research and biotechnology applications. That includes understanding the origins and diversification of life on earth, unravelling the functioning of complex ecosystem networks, understanding genetic change and its significance, identifying the genetic basis for adaptive traits that are useful for crop, livestock, fish and wildlife breeding programmes, and much more. </p>
<p>Having access to quality samples representing South Africa’s biodiversity saves time and resources needed to collect biological samples. The samples could even serve as a “bank” of genetic diversity that may be lost in future through climate change, loss of habitats or over-exploitation of natural resources.</p><img src="https://counter.theconversation.com/content/204382/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Hamer works for the South African National Biodiversity Institute and is an Honorary Associate Professor at the University of KwaZulu-Natal. She receives funding for the Biodiversity Biobanks South Africa from the Department of Science & Innovation. </span></em></p>The research conducted through biobanks can help to address challenges like climate change and food security.Michelle Hamer, Director, Collections Management, South African National Biodiversity InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2066742023-06-05T20:03:27Z2023-06-05T20:03:27ZHidden carbon: Fungi and their ‘necromass’ absorb one-third of the carbon emitted by burning fossil fuels every year<figure><img src="https://images.theconversation.com/files/529991/original/file-20230605-28427-m0nvgp.jpg?ixlib=rb-1.1.0&rect=4%2C7%2C1592%2C1190&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mycorrhizal fungi growing with a plant root </span> <span class="attribution"><span class="source">Dr Yoshihiro Kobae</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Beneath our feet, remarkable networks of fungal filaments stretch out in all directions. These mycorrhizal fungi live in partnership with plants, offering nutrients, water and protection from pests in exchange for carbon-rich sugars.</p>
<p>Now, <a href="https://doi.org/10.1016/j.cub.2023.02.027">new research</a> shows this single group of fungi may quietly be playing a <a href="https://www.nature.com/articles/s41467-019-13019-2">bigger role in storing carbon</a> than we thought. </p>
<p>How much bigger? These microscopic filaments take up the equivalent of more than a third (36%) of the world’s annual carbon emissions from fossil fuels – every year.</p>
<p>As we search for ways to slow or stop the climate crisis, we often look to familiar solutions: cutting fossil fuel use, switching to renewables and restoring forests. This research shows we need to look down too, into our soils. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529280/original/file-20230531-27-17lt2b.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This shows how mycorrhizal fungi (fine white filaments) connect to plant root systems (yellow) and out into the soil.</span>
<span class="attribution"><span class="source">Scivit/Wikipedia</span></span>
</figcaption>
</figure>
<h2>This fungi-plant partnership is 400 million years old</h2>
<p>Mycorrhizal fungi are hard to spot, but their effects are startling. They thread networks of microscopic filaments through the soil and into the roots of almost every plant on earth. </p>
<p>But this is no hostile takeover. They’ve been partnering with plants for <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1046/j.1469-8137.2002.00397.x">more than 400 million years</a>. The length of these complex relationships has given them a <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.13288">vital role</a> in our ecosystems. </p>
<p>Sometimes fungi take more than they give. But often, these are relationships of <a href="https://www.science.org/doi/full/10.1126/science.1208473">mutual benefit</a>. Through their network, the fungi transport essential nutrients and water to plants, and can even boost their <a href="https://doi.org/10.1111/nph.17781">resistance to pests and disease</a>. </p>
<p>In return, plants pump sugars and fat made by photosynthesis in their leaves down through their roots to the fungi. These compounds are rich in carbon, taken from the atmosphere.</p>
<h2>How do these fungi fit into the carbon cycle?</h2>
<p>On land, the natural carbon cycle involves a delicate balance. Plants take CO₂ from the atmosphere through photosynthesis, while other organisms emit it back into the atmosphere. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=844&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=844&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529486/original/file-20230601-22265-hn60tq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=844&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Carbon is captured by plants through photosynthesis, some of this carbon then goes into the networks of mycorrhizal fungi. These fungi also will release some of this carbon as CO₂ and as compounds into the soil.</span>
<span class="attribution"><span class="source">Adam Frew/Author provided using BioRender</span></span>
</figcaption>
</figure>
<p>Now we know the carbon transfer from plants to mycorrhizal fungi isn’t a side note – it’s a substantial part of this equation. </p>
<p>By analysing almost 200 datasets, the researchers estimate the world’s plants are transferring a staggering 3.58 billion tonnes of carbon per year to this underground network. That’s the same as 13.12 billion tonnes of CO₂ – more than a third of the world’s 36.3 billion tonnes of CO₂ emitted yearly by <a href="https://www.iea.org/reports/global-energy-review-co2-emissions-in-2021-2">burning fossil fuels</a>.</p>
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Read more:
<a href="https://theconversation.com/do-trees-really-stay-in-touch-via-a-wood-wide-web-heres-what-the-evidence-says-199806">Do trees really stay in touch via a 'wood-wide web'? Here's what the evidence says</a>
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<p>To be clear, fungal carbon doesn’t present a climate solution by itself. It’s a missing piece in the carbon cycle puzzle. </p>
<p>We still have big gaps in data from particular ecosystems and geographic regions. For instance, this study didn’t have any data of this kind from Australia or Southeast Asia – because it doesn’t yet exist.</p>
<figure class="align-center ">
<img alt="Microscope image of plant roots that have been stained to show the mycorrhizal fungal inside the root of a plant." src="https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=241&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=241&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=241&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=303&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=303&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529276/original/file-20230531-25-4m3nnt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=303&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">This image shows mycorrhizal fungi (blue) growing inside plant roots, where they obtain carbon and provide plants with access to resources such as nutrients.</span>
<span class="attribution"><span class="source">Adam Frew</span></span>
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<h2>What does this mean for the climate?</h2>
<p>We already know mycorrhizal fungi help soils retain carbon by releasing <a href="https://doi.org/10.1111/j.1574-6941.2007.00337.x">specific chemical compounds</a>. These compounds contain carbon and nitrogen. Once in the soil, these compounds can be used by other soil microorganisms, such as bacteria. When this happens it helps to form a highly stable soil carbon store that is more resistant to breakdown, and this store can accumulate <a href="https://doi.org/10.1111/nph.18914">more than four times faster</a> in the presence of mycorrhizal fungi.</p>
<p>When these fungi die, they leave behind “necromass” – a complex scaffold of dead organic material which can be stored in soil, and often inside clumps of soil particles. The carbon inside these clumps can stay in the soil for <a href="https://doi.org/10.2136/sssaj1994.03615995005800040023x">close to a decade</a> without being released back to the atmosphere.</p>
<p>In fact, other studies suggest this fungal necromass might <a href="https://doi.org/10.1016/j.soilbio.2021.108422">contribute more</a> to the carbon content of soil than living fungi.</p>
<p>But these fungi also naturally cause carbon to escape back <a href="https://doi.org/10.1146/annurev-ecolsys-110617-062331">to the atmosphere</a> by decomposing organic matter or changing water and nutrient availability, which influences how other organisms decompose. Mycorrhizal fungi also release some carbon back into the atmosphere, though the rate this happens <a href="https://doi.org/10.1016/j.soilbio.2021.108454">depends on many factors</a>. </p>
<p>What does this mean for climate change? While atmospheric CO₂ concentrations keep rising, it doesn’t necessarily mean fungi are storing more of it. Recent research in an <a href="https://doi.org/10.1038/s41586-020-2128-9">Australian woodland</a> found higher atmospheric CO₂ did see more carbon sent below the ground. But this carbon wasn’t stored for long periods. </p>
<p>To date, mycorrhizal fungi have been poorly represented in global carbon cycle models. They aren’t often considered when assessing which species are <a href="https://doi.org/10.1002/ppp3.10146">at risk of extinction</a> or <a href="https://doi.org/10.1111/rec.13866">promoting successful restorations</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529473/original/file-20230531-22265-5nd0xx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">We need more research to better understand the role of mycorrhizal fungi in the carbon cycle across different ecosystems, including in agriculture.</span>
<span class="attribution"><span class="source">Dylan de Jonge/Unsplash</span></span>
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<h2>Protecting our fungal networks</h2>
<p>When we cut down forests or clear land, we not only disrupt life above the ground, but <a href="https://doi.org/10.1111/gcb.12565">underground as well</a>. We need to safeguard these hidden fungal networks which give our plants resilience – and play a key role in the carbon cycle. </p>
<p>As we better understand how these fungi work and what we’re doing to them, we can also develop farming methods which better preserve them and their carbon. </p>
<p>As <a href="https://www.spun.earth/">global</a> and <a href="https://www.digupdirt.net/">Australian initiatives</a> continue to map the diversity of mycorrhizal fungi, scientists are working to understand what <a href="https://doi.org/10.1111/1365-2435.14349">shapes these communities</a> and <a href="https://doi.org/10.1111/nph.15119">their roles</a>. </p>
<p>We’ve long overlooked these vital lifeforms. But as we learn more about how fungi and plants cooperate and store carbon, it’s well past time for that to change. </p>
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Read more:
<a href="https://theconversation.com/the-secret-life-of-fungi-how-they-use-ingenious-strategies-to-forage-underground-156610">The secret life of fungi: how they use ingenious strategies to forage underground</a>
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<img src="https://counter.theconversation.com/content/206674/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Frew receives funding from the Australian Research Council, the British Ecological Society, and the Ecological Society of Australia.</span></em></p><p class="fine-print"><em><span>Jeff Powell receives funding from the Australian Research Council and NSW State Government. </span></em></p><p class="fine-print"><em><span>Carlos Aguilar-Trigueros and Natascha Weinberger do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research about underground fungal filaments suggests these networks store a vast amount of carbon. All the more reason to preserve them.Adam Frew, Lecturer and ARC DECRA Fellow, Western Sydney UniversityCarlos Aguilar-Trigueros, Postdoctoral fellow, Western Sydney UniversityJeff Powell, Professor and ARC Future Fellow, Western Sydney UniversityNatascha Weinberger, Postdoctoral Research Fellow, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2062202023-05-30T13:56:08Z2023-05-30T13:56:08ZFour dangers lurking in your garden – and how to protect yourself<figure><img src="https://images.theconversation.com/files/529077/original/file-20230530-29-d5un5v.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5487%2C3638&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The soil you use for your roses may contain something sinister.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-gardener-transplanting-red-roses-flowers-1675428565">Mariia Boiko/ Shutterstock</a></span></figcaption></figure><p>Many people see gardening as a relaxing pastime – an easygoing way to spend hours outdoors when the weather’s nice. But as a consultant in emergency medicine, I deal with all manner of medical emergencies and injuries arising from what may appear to be a harmless hobby.</p>
<p>Over the years, I have seen hand wounds from cutting implements and foot wounds from lawn mowers and garden forks. In recent weeks, I have seen falls from ladders, head wounds from falls on concrete – and, sadly, confirmed the death of a person in their later years whose enthusiastic shovelling proved too much. </p>
<p>Even in times past, the garden could be quite the health hazard. One of the <a href="https://www.ox.ac.uk/news/science-blog/penicillin-oxford-story">first patients</a> to be treated with penicillin was a police officer who had apparently contracted sepsis after a scratch from a rose thorn. In those days, the most minor of wounds could have the deadliest of consequences – and it turns out this can still happen, with a UK woman recently dying from sepsis after <a href="https://www.telegraph.co.uk/news/2016/10/03/solicitor-dies-from-sepsis-five-days-after-injuring-her-hand-gar/">scratching her hand while gardening</a>. </p>
<p>But these aren’t the only dangers lurking in your garden. Here are just a few things to look out for before you next head out to tend your plants:</p>
<h2>1. Tetanus</h2>
<p>Tetanus is a particularly nasty disease. The muscles go into spasm due to the effects of the toxin from the bacteria, <em>Clostridium tetani</em>. The <a href="https://www.ncbi.nlm.nih.gov/books/NBK459217/#:%7E:text=The%20clinical%20features%20of%20tetanus,that%20may%20cause%20respiratory%20distress">suffering</a> is almost indescribable, causing painful muscle spasms and a locked jaw. </p>
<p>Many associate tetanus with objects such as rusty nails. But this surprisingly common organism is also <a href="https://www.cdc.gov/tetanus/about/causes-transmission.html#:%7E:text=Tetanus%20is%20an%20infection%20caused,spread%20from%20person%20to%20person.">found in the soil</a>, particularly if manured, because <em>clostidia</em> are found in the gut. Roses like soil with manure, so this could turn these beloved flowers deadly if you get cut by contaminated thorns or if the soil gets into a cut. </p>
<p>Luckily, I have yet to see any cases in the emergency room because the UK immunises against tetanus. And I never want to see a case, because of how nasty it is. The case fatality rate can exceed 50% in people who aren’t immunised. This is why it’s important to check that your tetanus jab is up to date.</p>
<h2>2. Bacteria and fungi</h2>
<p>Lurking in a humble bag of compost is an ingredient many of us wouldn’t expect: <em>Legionella</em>.</p>
<p>This bacteria can cause an infection called <a href="https://www.gov.uk/government/collections/legionnaires-disease-guidance-data-and-analysis">Legionnaires’ disease</a> which is particularly harmful for the elderly and people with a compromised immune system. It can lead to a nasty and often fatal pneumonia when inhaled. Warm, stagnant water involved in the composting process may account for its presence. </p>
<p>It isn’t only pre-packaged compost that’s hazardous. Your own compost heap is also be filled with various bacteria and fungi, which, if properly maintained, should cause you no trouble. But often the mould <em><a href="https://www.nature.com/articles/s41564-022-01091-2?utm_medium=affiliate&utm_source=commission_junction&utm_campaign=CONR_PF018_ECOM_GL_PHSS_ALWYS_DEEPLINK&utm_content=textlink&utm_term=PID100060515&CJEVENT=2b6b1daafeca11ed826d8a170a18b8fb#change-history">Aspergillus</a></em> can grow when it’s hot outside. This can give rise to some <a href="https://thorax.bmj.com/content/70/3/270">nasty lung lesions</a> and may even become more widespread in the body – especially in the elderly and immunosuppressed and can be fatal.</p>
<p>Mould spores can also <a href="https://pubmed.ncbi.nlm.nih.gov/7719883/">trigger allergies</a> in some people, a condition known as extrinsic allergic alveolitis or “<a href="https://www.ncbi.nlm.nih.gov/books/NBK557580/">farmer’s lung</a>”. This condition was classically due to exposure to mouldy hay, but compost heaps can also do the same because of the presence of organisms such as <em>Aspergillus</em> and the bacteria <em>Actinomycetes</em>.</p>
<h2>3. Leptospirosis</h2>
<p><em>Leptospira</em> is a bacterium that may be found in water contaminated with rat urine. With rats often building habitats near humans, it might be best to take care near the pond or rainwater barrels when gardening. </p>
<figure class="align-center ">
<img alt="A rat in a garden looking at a wooden fence." src="https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=470&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=470&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529078/original/file-20230530-23-iaic5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=470&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Beware if you have rats in your garden.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rat-garden-1842737110">battybattrick/ Shutterstock</a></span>
</figcaption>
</figure>
<p><em>Leptospira</em> can cause leptospirosis, a <a href="https://www.cdc.gov/leptospirosis/symptoms/index.html">rather unpleasant infection</a> that causes headaches, fevers, chills, vomiting, jaundice and then later, liver failure, kidney failure and meninigitis. </p>
<h2>4. Power tools</h2>
<p>While power tools can make our work easier in the garden, they can also make it much easier to injure ourselves, too. Hedge trimmers may be a great way to tame trees and bushes, but they can also amputate digits and <a href="https://www.dailymail.co.uk/news/article-9441081/Tragedy-man-dies-injuring-hedge-trimmer-Sydneys-leafy-northern-suburbs.html">inflict wounds</a> very efficiently. Be sure to wait until the hedge trimmer is fully turned off before clearing any branches you’ve removed. </p>
<p>Hedge trimmers and lawn mowers can also easily cut through electric cables, which can lead to electrocution. Power tools can also be <a href="https://www.standard.co.uk/hp/front/wife-killed-in-chainsaw-accident-7081566.html">disastrous</a> if you fall while up a ladder and if you have <a href="https://news.stv.tv/east-central/death-of-man-electrocuted-by-hedge-trimmer-could-have-been-prevented">power lines crossing your garden</a>, then please avoid them.</p>
<h2>Stay safe</h2>
<p>While these hidden dangers are certainly a risk, luckily there are many simple things you can do to avoid harm from them, including: </p>
<ol>
<li><p>Cleaning and covering wounds while gardening.</p></li>
<li><p>Make sure your <a href="https://www.rose.org/single-post/2018/04/27/tetanus-some-things-you-should-know">immunisations</a> are up to date (especially for tetanus). </p></li>
<li><p>Keeping <a href="https://www.rhs.org.uk/advice/health-and-wellbeing/minimising-health-risks-in-the-garden">compost bags</a> away from your face when you open them.</p></li>
<li><p>Deter rats by not putting cooked food on <a href="https://www.growveg.com/guides/how-to-keep-rats-out-of-your-compost/#:%7E:text=Rats%20don't%20like%20disturbance,and%20fats%20to%20the%20bin.">compost heaps</a>, <a href="https://www.ciphe.org.uk/public/plumbing-health-hazards/gardens/">covering water butts</a> and setting up traps if you have an infestation.</p></li>
<li><p>Set up ladders firmly on even ground away from power lines.</p></li>
<li><p>Enjoy having wildlife but <a href="https://www.theguardian.com/environment/2014/aug/07/man-bitten-three-times-adder">leave it alone</a> (snakes can be just as much a danger as rats).</p></li>
</ol>
<p>And one last piece of advice from me. Every year the burns unit at my hospital sees a number of people who have tried to speed up the process of lighting their barbecue or bonfire by <a href="https://www.mirror.co.uk/news/us-news/dad-suffers-horrific-burns-after-21844521">using petrol</a>. Not all survive. So if you are planning to cook the fruits of your labours on a barbecue in your garden, make sure you don’t use inflammable liquids to get the flame started, and have a fire extinguisher on hand just in case.</p>
<p>Gardening is a rewarding hobby that has many health benefits. Just be sure to take sensible precautions.</p><img src="https://counter.theconversation.com/content/206220/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen Hughes does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Gardening is often seen as a relaxing, harmless pasttime – but that isn’t always the case.Stephen Hughes, Senior Lecturer in Medicine, Anglia Ruskin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2033712023-05-11T12:27:42Z2023-05-11T12:27:42ZBrain-altering fungi could lead the next frontier in mental health care<figure><img src="https://images.theconversation.com/files/525125/original/file-20230509-17-pzcku9.jpg?ixlib=rb-1.1.0&rect=26%2C0%2C5964%2C3520&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fungal metabolites, such as psilocybin, may have therapeutic potential.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cultivation-recreational-psilocybin-mushrooms-world-medical-1779792026">Kyrylo Vasyliev/ Shutterstock</a></span></figcaption></figure><p>If you were one of the millions of people who watched HBO’s TV series <a href="https://theconversation.com/the-last-of-us-a-show-that-surprised-and-challenged-audiences-even-those-who-had-played-the-game-201814">The Last of Us</a>, you probably have a heightened awareness of the threat that fungi can have to our health.</p>
<p>The series is set in a post-apocalyptic world where parasitic fungi take control of the human brain, turning people into killer zombies. The scariest part of this premise is that it’s not entirely implausible. Parasitic or “zombie” fungi that alter <a href="https://www.theatlantic.com/science/archive/2017/11/how-the-zombie-fungus-takes-over-ants-bodies-to-control-their-minds/545864/">the mind and behaviour of their hosts</a> do exist. </p>
<p>Fortunately, real-life zombie fungi (known as <em>Cordyceps</em>) only infect insects. The fungus hijacks their bodies for the sole purpose of spreading its seed-like fungal spores. When spores are ingested by insects, they germinate and grow, secreting molecules that travel to the host’s brain and interfere with its function.</p>
<p>The fungus compels the insect to forego its aversion to heights and climb upwards. Upon reaching a position optimal for fungal survival, the fungus induces the “death grip” and then devours its host from the inside-out, sprouting spore-containing mushrooms from the insect carcass.</p>
<h2>Fungi that alter our minds</h2>
<p>In the case of humans, some fungi which produce small molecules, or <a href="https://pubmed.ncbi.nlm.nih.gov/27809954/">metabolites</a>, that alter our minds – and recent research shows these have therapeutic potential. The most widely known is the hallucinogen psilocybin – the active ingredient in magic mushrooms. LSD, or lysergic acid diethylamide, is another psychedelic with fungal origins. </p>
<p>Humans have known about the hallucinogenic properties of fungi for centuries. <a href="https://www.sciencedirect.com/science/article/pii/S2173580814001527">The Aztecs</a> even gave magic mushrooms to people who were dying to promote a peaceful transition to the afterlife. </p>
<p>But recently, there’s been an <a href="https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2772630">explosion of interest</a> in fungal metabolites, specifically because of their <a href="https://www.nejm.org/doi/full/10.1056/nejmoa2032994">neurological benefits</a> and potential in treating mental health conditions. And it’s no wonder, given the mechanisms fungal metabolites use to interact with our nervous system.</p>
<p>Think of our brain like a map. When we’re young, we explore all corners of this map, sending out connections in every direction to make sense of our environment. Before long, we figure out basic truths – such as how to secure food, or where we live – and the neurological paths that make up these connections strengthen. </p>
<p>Over time, a network emerges that reflects our unique experiences. Regions we re-visit often will develop established paths, whereas under-used connections will fade away.</p>
<p>Conditions such as addiction, chronic depression and post-traumatic stress disorder (PTSD) are characterised by processes such as <a href="https://pubmed.ncbi.nlm.nih.gov/25264228/">repetitive negative thinking</a> or <a href="https://pubmed.ncbi.nlm.nih.gov/27911470/">rumination</a>, where patients focus on negative thoughts in a counterproductive way. Unfortunately, these <a href="https://pubmed.ncbi.nlm.nih.gov/25264228/">strengthen brain connections</a> that perpetuate the unfavourable mental state.</p>
<p>But it’s believed that fungal metabolites give our brain the freedom to explore less-visited territories again. Psychedelic “trips” are thought to allow people to <a href="https://www.amazon.co.uk/Psychedelic-Experience-Tibetan-Penguin-Classics/dp/0141189630/ref=sr_1_1?crid=31L001ENA3N3M&keywords=the+psychedelic+experience+timothy+leary&qid=1683542508&sprefix=the+psychedelic+%2Caps%2C90&sr=8-1">experience a world without the boundaries of reality</a> – and more recent research suggests this is a manifestation of novel brain exploration.</p>
<p>For example, psilocybin stimulates a receptor in the brain called 5-HT2a. This receptor usually binds to serotonin, a chemical in our body which controls communication between specific nerve cells. But when psilocybin binds to the 5-HT2a receptor, it <a href="https://www.nature.com/articles/s41467-022-33578-1">makes it easier for our brain</a> to change and generate new connections (including causing hallucinations at high doses). We call this an increase in <a href="https://pubmed.ncbi.nlm.nih.gov/34566723/">neuroplasticity</a>. </p>
<p>Although the effects of a single large dose of psychedelics are transitory, evidence shows administering two smaller doses of psilocybin three weeks apart leads to a sustained <a href="https://www.nature.com/articles/s41591-022-01744-z">increase in connectivity</a> between different functional regions of the brain. Such changes in neuroplasticity have the potential to <a href="https://www.nature.com/articles/s41591-022-01744-z">disrupt the rigid thought patterns</a> that underlie certain mental health conditions.</p>
<figure class="align-center ">
<img alt="A young man speaks with his therapist." src="https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525129/original/file-20230509-22-rqqpu9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Combining psychedelics with traditional therapy methods could make therapy more beneficial.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/stressed-black-man-explaining-his-problems-1793034835">Prostock-studio/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Furthermore, by increasing neuroplasticity, it is believed that psychedelics allow people to <a href="https://www.amazon.co.uk/How-Change-Your-Mind-Psychedelics/dp/0141985135/ref=asc_df_0141985135/?tag=googshopuk-21&linkCode=df0&hvadid=347799774948&hvpos=&hvnetw=g&hvrand=1060708585039904868&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045208&hvtargid=pla-547776848553&psc=1&th=1&psc=1">view life situations from a new perspective</a>. Combining psychedelics with more traditional talking therapy could make it possible to explore – and more fully understand – the initial trigger for negative thought patterns. This could potentially prevent the same negative cycle reestablishing after treatment. Indeed, research showed that combining therapy with psilocybin had a <a href="https://journals.sagepub.com/doi/10.1177/02698811211073759">prolonged anti-depressive effect</a> in adults with major depressive disorder.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/35225143/">Additional studies</a> demonstrate the positive effect of fungal metabolites in treating a <a href="https://pubmed.ncbi.nlm.nih.gov/35225143/">range of conditions</a> – including anxiety, depression and alcohol addiction. These studies also point out that psilocybin can affect the symptoms after only one or two doses – whereas anti-depressants may take many months to work.</p>
<h2>No miracle cure</h2>
<p>That said, psychedelics should not be considered a miracle cure as there is still a lot we don’t know. Furthermore, most studies on psychedelics are still preliminary as they use a limited number of participants. As such, <a href="https://www.health.harvard.edu/blog/the-popularity-of-microdosing-of-psychedelics-what-does-the-science-say-202209192819">experts are divided</a> on the efficacy of psychedelic treatment. Furthermore, psychedelics are powerful and unpredictable – and the safety and long-term effects of such treatment is unknown.</p>
<p>But given the current <a href="https://www.bma.org.uk/advice-and-support/nhs-delivery-and-workforce/pressures/mental-health-pressures-data-analysis">mental health crisis</a>, any intervention that offers a new approach to tackling these conditions – especially those that are treatment-resistant – needs to be carefully considered and rigorously researched. </p>
<p>Excitingly, many countries <a href="https://compasspathways.com/compass-pathways-receives-fda-breakthrough-therapy-designation-for-psilocybin-therapy-for-treatment-resistant-depression/">recognise the benefits</a> of psychedlics for mental health treatment. The Australian government even <a href="https://www.tga.gov.au/news/media-releases/change-classification-psilocybin-and-mdma-enable-prescribing-authorised-psychiatrists">legalised prescription psilocybin</a> for medicinal use in 2022. Although the UK doesn’t yet permit the prescription of psychedelics, <a href="https://www.imperial.ac.uk/psychedelic-research-centre/">multiple research centres</a> are undertaking trials to establish the <a href="https://www.kcl.ac.uk/research/psychoactive-trials-group">mental health benefits</a> of fungal metabolites. </p>
<p>While there’s still much we don’t know about fungal metabolites – including whether other molecules exist that have a similar effect on neurological function – it’s clear they have great potential in mental health treatment. Perhaps it’s time for us to relinquish certain negative connotations we have of illicit fungal drugs, and become comfortable thinking of brain-altering psychedelics as medicine.</p><img src="https://counter.theconversation.com/content/203371/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edel Hyland does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Psilocybin, the active ingredient in magic mushrooms, is one example of a fungus which can alter the human mind.Edel Hyland, Senior Lecturer in Biochemistry & Fungal Biology, Queen's University BelfastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2034952023-05-03T12:10:09Z2023-05-03T12:10:09ZHow do ‘Candida auris’ and other fungi develop drug resistance? A microbiologist explains<figure><img src="https://images.theconversation.com/files/523473/original/file-20230428-18-9slhum.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2073%2C1368&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Candidiasis is a severe fungal infection that can spread easily in medical facilities.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/8ysD2e">Atlas of Pulmonary Pathology/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>One of the scariest things you can be told when at a doctor’s office is “You have an antimicrobial-resistant infection.” That means the bacteria or fungus making you sick can’t be easily killed with common antibiotics or antifungals, making treatment more challenging. You might have to take a combination of drugs for weeks to overcome the infection, which could result in more severe side effects.</p>
<p>Unfortunately, this diagnosis is <a href="https://www.who.int/publications/i/item/9789240062702">becoming more common around the world</a>.</p>
<p>The yeast <em><a href="https://doi.org/10.1128/jcm.01588-17">Candida auris</a></em> has recently emerged as a potentially dangerous fungal infection for hospital patients and nursing home residents. First <a href="https://doi.org/10.3947%2Fic.2022.0008">discovered in the late 2000s</a>, <em>Candida auris</em> has very quickly become a <a href="https://doi.org/10.3390/microorganisms9040807">major health challenge</a> due to its ease of spread and ability to resist common antifungal drugs.</p>
<p>How did this fungus become so strong, and what can researchers and physicians do to combat it? </p>
<p><a href="https://scholar.google.com/citations?user=U69z9VsAAAAJ&hl=en&oi=ao">I am a microbiologist</a> researching new ways to kill fungi. <em>Candida auris</em> and other fungi use three common cellular tricks to overcome treatments. Luckily, exciting new research hints at ways we can still fight this fungus.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VOn5Udfx7eQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Drug-resistant <em>Candida auris</em> infections are on the rise in the U.S. and around the world.</span></figcaption>
</figure>
<h2>Targeting the sensitive parts of fungal cells</h2>
<p>Fungal cells contain a structure called a <a href="https://doi.org/10.1128/microbiolspec.funk-0035-2016">cell wall</a> that helps maintain their shape and protects them from the environment. Fungal cell walls are constructed in part from several different types of polysaccharides, which are long strings of sugar molecules linked together. </p>
<p>Two polysaccharides found in almost all fungal cell walls are <a href="https://doi.org/10.1016/j.mib.2010.05.002">chitin</a> and <a href="https://doi.org/10.1016/j.tcsw.2019.100022">beta-glucan</a>. The fungal cell wall is an attractive target for drugs because human cells do not have a cell wall, so drugs that block chitin and beta-glucan production will have fewer side effects. </p>
<p>Some of the most common drugs used to treat fungal infections are called <a href="https://doi.org/10.4103%2F0253-7613.62396">echinocandins</a>. These drugs stop fungal cells from making beta-glucan, which significantly weakens their cell wall. This means the fungal cell can’t maintain its shape well. While the fungus is struggling to grow or is breaking apart, your immune system has a much better chance of fighting off the infection. </p>
<h2>How fungi become drug resistant</h2>
<p>Unfortunately, some strains of <em>Candida auris</em> are resistant to echinocandin treatment. But how does the fungus actually do it? For decades, scientists have been studying how fungi overcome drugs designed to weaken or kill them. In the case of echinocandins, <em>Candida auris</em> commonly uses three tricks to beat these treatments: <a href="https://doi.org/10.1128/AAC.00238-18">hide</a>, <a href="https://doi.org/10.1101%2Fcshperspect.a019752">build</a> and <a href="https://doi.org/10.3389/fmicb.2019.02573">change</a>. </p>
<p>The first trick is to hide in a complex mixture of sugars, proteins, DNA and cells <a href="https://doi.org/10.1128/msphere.00458-19">called a biofilm</a>. Made with irregular 3D structures, biofilms have lots of places for cells to hide. Drugs aren’t good at penetrating biofilms, so they can’t access and kill cells deep inside. Biofilms are especially problematic when they <a href="https://doi.org/10.3390/antibiotics4010001">grow on</a> <a href="https://doi.org/10.2147/ijn.s353071">medical equipment</a> like ventilators or catheters. Once free of a biofilm, cells that have gained the ability to resist the drugs a patient was taking become more dangerous.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of two types of Candida attaching to each other" src="https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523471/original/file-20230428-26-n4nxfs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This image shows <em>Candida albicans</em> (red) producing branching filaments that allow it to attach to <em>Candida glabrata</em> (green), forming biofilms. Both of these species can cause infections in people.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/HE7JbY">Edgerton Lab, State University of New York at Buffalo/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>The second trick fungi use to evade treatment is to build cell walls differently. Fungal cells treated with echinocandins can’t make beta-glucan. So instead, they start to <a href="https://doi.org/10.3109/13693786.2011.577104">make more chitin</a>, another important polysaccharide in the fungal cell wall. Echinocandins are unable to stop chitin production, so the fungus is still able to build a strong cell wall and avoid being killed. While there are some drugs that can <a href="https://doi.org/10.3390/jof6040261">stop chitin production</a>, none are currently approved for use in people. </p>
<p>The third trick fungi rely on is to <a href="https://doi.org/10.3389/fmicb.2019.02788">change the shape of the</a> <a href="https://doi.org/10.1093/cid/civ791">beta-glucan production enzyme</a> so echinocandins cannot block it. These mutations allow beta-glucan production to continue even in the presence of the drug. It is not surprising that <em>Candida</em> uses this trick to resist antifungal drugs since it is <a href="https://doi.org/10.1111%2Fnyas.12831">very effective</a> at keeping the cells alive. </p>
<h2>New tactics to fight fungi</h2>
<p>What can be done to treat echinocandin-resistant fungal infections? Thankfully, scientists and physicians are researching new ways to kill <em>Candida auris</em> and similar fungi. </p>
<p>The first approach is to find new drugs. For example, there are two drugs in development, <a href="https://doi.org/10.3390/antibiotics9050227">rezafungin</a> and <a href="https://doi.org/10.4155%2Ffmc-2018-0465">ibrexafungerp</a>, that appear to be able to stop beta-glucan production even in fungi resistant to echinocandins. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of budding yeast cells" src="https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523474/original/file-20230428-14-z7579n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This microscopy image shows budding yeast cells.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/budding-yeast-cell-in-gram-stain-royalty-free-image/1464904014">toeytoey2530/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>A complementary approach my research group is exploring is whether a class of enzymes called <a href="https://doi.org/10.1007/s11274-016-2068-6">glycoside hydrolases</a> might also be able to combat drug-resistant fungi. Some of these enzymes actively destroy the fungal cell wall, breaking apart both beta-glucan and chitin at the same time, which could potentially help prevent fungi from surviving on medical equipment or on hospital surfaces.</p>
<p>My lab’s work on discovering enzymes that strongly degrade fungal cell walls is part of a new strategy to combat antifungal resistance that uses a combination of approaches to kill fungi. But the end goal of this research is the same: having a physician tell you, “You’ve got a fungal infection, but we have a good treatment for it now.”</p><img src="https://counter.theconversation.com/content/203495/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeffrey Gardner receives funding from the National Science Foundation (NSF) and the National Institutes of Health (NIH).</span></em></p>Multidrug-resistant fungal infections are an emerging global health threat. Figuring out how fungi evade treatments offers new avenues to counter resistance.Jeffrey Gardner, Associate Professor of Biological Sciences, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2007912023-04-10T12:04:23Z2023-04-10T12:04:23ZHow do trees die?<figure><img src="https://images.theconversation.com/files/517217/original/file-20230323-26-hsn4ob.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6001%2C4232&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Eventually weather, pests and disease will take their toll, but the story doesn't end there. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/dried-dead-tree-with-moss-trees-in-forest-royalty-free-image/1392619431">Emanuel David / 500px via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>How and why do trees die? – Anish K., age 11, Boston, Massachusetts</strong></p>
</blockquote>
<hr>
<p>Trees can die suddenly or quite slowly. </p>
<p>Fire, flood or wind can cause a quick death by severely damaging a tree’s ability to <a href="https://www.treehugger.com/process-of-using-water-by-trees-1343505">transport water and nutrients</a> up and down its trunk. </p>
<p>Sometimes a <a href="https://www.youtube.com/watch?v=vR30qlK0-Cw">serious insect attack</a> or disease can kill a tree. This kind of death usually takes from a few months to a couple of years. Again, a tree loses its ability to move water and nutrients, but does so in stages, more slowly. </p>
<p>A tree can also die of what you might call old age.</p>
<p>I am a <a href="https://scholar.google.com/citations?hl=en&user=g2KEhV4AAAAJ">scientist who studies trees</a> and the web of living things that surround them. The death of a tree is not exactly what it seems, because it directly leads to new life.</p>
<h2>Different trees, different life spans</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of an enormous old living tree." src="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An ancient bristlecone pine (<em>Pinus longaeva</em>) in Patriarch Grove in California’s White Mountains.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nturland/5817568646/in/photostream/">Nicholas Turland/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Trees can live an <a href="https://www.scientificamerican.com/article/trees-have-the-potential-to-live-indefinitely">incredibly long time</a>, <a href="https://onetreeplanted.org/blogs/stories/oldest-tallest-biggest-trees">depending on what kind they are</a>. Some <a href="https://www.nps.gov/grba/planyourvisit/identifying-bristlecone-pines.htm">bristlecone pines</a>, for instance, are among the oldest known trees and are more than 4,000 years old. Others, like lodgepoles or poplars, will have much shorter life spans, from 20 to 200 years. The biggest trees in your neighborhood or town are probably somewhere in that range. </p>
<p>You’ve probably noticed that different living things have different life spans – a hamster is generally not going to live as long as a cat, which isn’t going to live as long as a person. Trees are no different. Their life spans are determined by their DNA, which you can think of as the <a href="https://kids.britannica.com/kids/article/DNA/390730">operating system embedded in their genes</a>. Trees that are programmed to grow very quickly will be less strong – and shorter lived – <a href="https://extension.psu.edu/why-do-some-trees-live-longer-than-others">than ones that grow very slowly</a>. </p>
<p>But even a tough old tree will eventually die. The years and years of damage done by insects and microscopic critters, combined with abuse from the weather, will slowly end its life. The death process may start with a single branch but will eventually spread to the entire tree. It may take a while for an observer to realize a tree has finally died. </p>
<p>You might think of death as a passive process. But, in the case of trees, it’s surprisingly active. </p>
<h2>The underground network</h2>
<p>Roots do more than anchor a tree to the ground. They are the place where microscopic fungi attach and <a href="https://www.nytimes.com/interactive/2020/12/02/magazine/tree-communication-mycorrhiza.html">act like a second root system for a tree</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of thin spiderweb-looking filaments attached to roots." src="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some fungi look like fragile spiderwebs, but these tiny tubes act like superhighways underground.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Mycorhizes-01.jpg">André-Ph. D. Picard</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Fungi form long, superfine threads called hyphae. Fungal hyphae can <a href="https://www.scientificamerican.com/article/do-trees-support-each-other-through-a-network-of-fungi">reach much farther than a tree’s roots can</a>. They gather nutrients from the soil that a tree needs. In exchange, the tree repays fungi with <a href="https://www.youtube.com/watch?v=D1Ymc311XS8">sugars it makes out of sunlight</a> in a process known as <a href="https://www.britannica.com/science/photosynthesis">photosynthesis</a>. </p>
<p>You might have heard that fungi can also pass nutrients from one tree to another. This is a topic that scientists are still working out. Some trees are likely connected to other trees by a complex underground network of fungi, sometimes called the “<a href="https://www.newyorker.com/tech/annals-of-technology/the-secrets-of-the-wood-wide-web">wood wide web</a>.”</p>
<p>How the wood wide web functions in a forest is still not well understood, but scientists do know that the fungi forming these networks are important for keeping trees healthy.</p>
<h2>Afterlife of a tree</h2>
<p>Before it topples over, a dead tree can stand for many years, providing a safe home for bees, squirrels, owls and <a href="https://www.nwf.org/Garden-for-Wildlife/Cover/Trees-and-Snags">many more animals</a>. Once it falls and becomes a log, it can host other living things, like badgers, moles and reptiles. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A mossy trunk from a dead tree lies in the forest." src="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">One day the remains of this tree will be completely gone.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/october-2021-lower-saxony-uslar-a-mossy-trunk-from-a-dead-news-photo/1236121962">Swen Pförtner/picture alliance via Getty Images</a></span>
</figcaption>
</figure>
<p>Logs also host a different kind of fungi and bacteria, called decomposers. These <a href="https://vinsweb.org/the-fallen-log/">tiny organisms help break down big dead trees</a> to the point where you would never know they had existed. Depending on the conditions, this process can take from a <a href="https://vinsweb.org/the-fallen-log/">few years to a century or more</a>. As wood breaks down, its nutrients return to the soil and become available for other living things, including nearby trees and fungal networks.</p>
<p>A tree leaves a legacy. While alive, it provides shade, home for many animals and a lifeline to fungi and other trees. When it dies, it continues to play an important role. It gives a boost to new trees ready to take its place, shelter to a different set of animals and, eventually, nourishment for the next generation of living things.</p>
<p>It’s almost as if a tree never truly dies but just passes its life on to others.</p>
<hr>
<p><em>Editor’s note: This story has been updated to emphasize that much remains unknown about the relationship between trees and fungi.</em></p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/200791/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Camille Stevens-Rumann does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Even in death, a tree helps others live.Camille Stevens-Rumann, Assistant Professor of Forest & Rangeland Stewardship, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2024932023-03-29T12:01:41Z2023-03-29T12:01:41ZCandida auris: what you need to know about the deadly fungus spreading through US hospitals<p>A fungal superbug called <em>Candida auris</em> is spreading rapidly through hospitals and nursing homes in the US. The first case was identified in 2016. Since then, it has spread to <a href="https://www.cdc.gov/fungal/candida-auris/tracking-c-auris.html">half the country’s 50 states</a>. And, according to a <a href="https://www.acpjournals.org/doi/10.7326/M22-3469">new report</a>, infections tripled between 2019 and 2021. This is hugely concerning because <em>Candida auris</em> is resistant to many drugs, making this fungal infection one of the hardest to treat.</p>
<p><em>Candida auris</em> is a yeast-type fungus that is the first to have multiple international health alerts associated with it. It has been found in <a href="https://www.cdc.gov/fungal/candida-auris/candida-auris-qanda.html#:%7E:text=C.%20auris%20infections%20have%20been,countries%2C%20including%20the%20United%20States.">over 30 countries</a>, including the UK, since it was first identified in Japan in 2009.</p>
<p>It is related to other types of yeast that can cause infections, like <em>Candida albicans</em> which causes thrush. However, <em>Candida auris</em> is very different to these other fungi and in some ways, highly unusual.</p>
<p>First, it can grow, or “<a href="https://pubmed.ncbi.nlm.nih.gov/33385336/">colonise</a>”, human skin. Unlike many other Candida species that like to grow in our guts as part of the microbiome, <em>Candida auris</em> does not grow in this environment and <a href="https://pubmed.ncbi.nlm.nih.gov/33385336/">seems to prefer the skin</a>. This means that people who are colonised with <em>Candida auris</em> can shed lots of yeast from their skin, and this <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008563">contaminates bed clothes and surfaces</a> with the fungus. This can lead to outbreaks.</p>
<p>It is unusual for a fungal infection to spread from person to person, but that seems to be how <em>Candida auris</em> infections spread. Outbreaks can happen with this fungus, especially in intensive care units (ICU) and nursing homes where people are at a higher risk for getting fungal infections generally. </p>
<p>The fungus can live on surfaces for <a href="https://www.cdc.gov/fungal/candida-auris/c-auris-drug-resistant.html">several weeks</a>, and getting rid of it can be difficult. <a href="https://www.gov.uk/government/publications/candida-auris-infection-control-in-community-care-settings">Enhanced cleaning and hand washing</a> is needed to try and limit the spread of the fungus and exposure to patients who get ill from it. </p>
<p>Most people who are colonised with <em>Candida auris</em> will not get ill from it, or even know it is there. It <a href="https://www.gov.uk/government/publications/candida-auris-a-guide-for-patients-and-visitors">causes infections</a> when it gets into surgical wounds or the blood from an intravenous line. Once it gets into the body, it can infect organs and the blood causing a very serious and potentially fatal disease. </p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9344200/">mortality rate</a> for people infected (as opposed to colonised) with the fungus is between 30 and 60%. But a precise mortality rate can be hard to pin down as people who are infected are often critically ill with other conditions.</p>
<p>Diagnosing an infection can be difficult as there can be a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211321/#S0004title">wide range of symptoms</a> including fever, chills, headaches and nausea. It is for this reason that we need to keep a close eye on <em>Candida auris</em> as it can easily be confused with other conditions. </p>
<p>In the last few years, new tests to help identify this fungus accurately have been developed.</p>
<figure class="align-center ">
<img alt="A healthcare professional putting an IV line in the back of a patient's hand." src="https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517943/original/file-20230328-480-mklbx5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Candida auris can get into the body via an infected IV line.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cropped-image-female-nurse-attaching-iv-224584333">Tyler Olson/Shutterstock</a></span>
</figcaption>
</figure>
<p>The first <em>Candida auris</em> infection was reported in the UK in 2013. However, there may have been other cases before this – there is evidence that some early cases were <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008563">misidentified</a> as unrelated yeasts.</p>
<p>The UK has so far managed to stop any major outbreaks, and most cases have been <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008563">limited in their spread</a>. </p>
<p>Most patients who have become ill from <em>Candida auris</em> in the UK had recently travelled to parts of the world where the fungus is <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008563">more common or has been circulating for longer</a>. </p>
<h2>Spurred by COVID</h2>
<p>Rising numbers of <em>Candida auris</em> infections are thought to be partially linked to the COVID pandemic. People who become very ill from COVID may need mechanical ventilation and long stays in the ICU, which are both <a href="https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008563">risk factors</a> for <em>Candida auris</em> colonisation and infection. </p>
<p>It will take some time to figure out exactly how the pandemic has affected rates and numbers of fungal infections around the world, but these are important questions to answer to help predict how <em>Candida auris</em> cases might fluctuate in the future.</p>
<p>As for most life-threatening fungal infections, treatment is difficult and limited. We have only a handful of antifungal drugs to fight these infections, so when a species is resistant to one or more of these drugs, the options for treatment are extremely limited. Some <em>Candida auris</em> infections are resistant to <a href="https://www.cdc.gov/fungal/candida-auris/c-auris-drug-resistant.html#:%7E:text=It%20can%20spread%20in%20hospitals,on%20surfaces%20for%20several%20weeks.">all three types of antifungal drug</a>. </p>
<p>Healthcare professionals must remain vigilant to this drug-resistant fungus. Without close monitoring and enhanced awareness of this infection, we could see more outbreaks and serious disease associated with <em>Candida auris</em> in the future.</p><img src="https://counter.theconversation.com/content/202493/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca A. Drummond receives funding from the Medical Research Council. </span></em></p>A drug-resistant fungus is a threat to human health.Rebecca A. Drummond, Associate Professor, Immunology and Immunotherapy, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1982782023-03-15T16:56:38Z2023-03-15T16:56:38ZClimate crisis threatens truffle production but could put UK species back on the menu<p><a href="https://ww3.rics.org/uk/en/journals/land-journal/truffle-production-uk-investment.html">Truffles</a>, the prized fungi coveted worldwide by chefs and food connoisseurs, have long been held in high regard. </p>
<p>Often associated with Mediterranean Europe, especially France, Italy and Spain, these tasty fungi grow underground and are unearthed with the help of scent-detection dogs.</p>
<p>But unbeknown to many is the fact that the UK once had a thriving industry focused on a native truffle species (<em>Tuber aestivum</em>), with the English truffle first <a href="https://doi.org/10.1098/rstl.1693.0047">recorded</a> in 1693. </p>
<p>From this point on there are many accounts of the UK’s thriving truffle industry, including <a href="https://en.wikisource.org/wiki/Mrs._Beeton%27s_Book_of_Household_Management">writings</a> by celebrated chef <a href="https://www.englishtruffles.co.uk/truffles-about/history-of-english-truffles/">Mrs Beeton</a> in 1861. However, changing socioeconomic conditions and a loss of habitat eventually led to a collapse of the industry, and truffle harvesting in the UK went to ground. </p>
<p>Some hunters were still able to find truffles. This was mainly for personal use, but some were still sold to local restaurants or pubs by lucky hunters – though only on a very small scale. Official markets had disappeared.</p>
<p>This slump wasn’t unique to the UK. A similar story played out in France, although the French had enough crops to keep the industry alive. The decline was eventually stemmed in France in the 1970s thanks to a new technique, whereby truffles were cultivated by inoculating the roots of oak and hazel trees with truffle spores. </p>
<p>News of this success spread to the UK, where truffle-inoculated trees from the Mediterranean began to be imported. But applying methods that worked in the Mediterranean to the UK’s temperate climate failed to produce any truffles.</p>
<p>This changed when my colleagues and I pioneered a new approach that took into account the UK climate. Rather than replicating Mediterranean methods, we instead focused on seeds and spores adapted to local conditions. This led to the harvest of England’s first cultivated truffle, in Leicestershire in <a href="https://plantationsystems.com/the-first-ever-cultivated-british-truffle-making-history/">2015</a>. </p>
<p>This was swiftly followed by Wales’ first cultivated truffle in <a href="https://www.itv.com/news/wales/2016-07-25/first-ever-cultivated-truffle-harvested-in-wales">2016</a> and Scotland in <a href="https://www.stir.ac.uk/news/2017/12/summer-black-truffles-cultivated-in-scotland-for-first-time/">2017</a>. And just across the water, the Republic of Ireland joined the group of Celtic truffle producers when two orchards <a href="https://www.stir.ac.uk/news/2017/12/summer-black-truffles-cultivated-in-scotland-for-first-time/">began production</a> in 2022. </p>
<p>This revival of the British and Irish truffle industries is particularly encouraging given my <a href="https://doi.org/10.1016/j.scitotenv.2018.11.252">recent research</a> shows that global production is at risk due to the climate crisis. But my work also suggests that UK truffles may be set to prosper in these conditions.</p>
<h2>Truffles at risk?</h2>
<p>Myself and a colleague have used historical data to anticipate the impact of climate change on truffle production. Our data suggests there will likely be a huge decline in Mediterranean harvests by 2071. </p>
<p>We are now starting to see evidence of this, with poor harvests linked to drier conditions. But what we hadn’t anticipated was the impact closer to home – with 2022 the worst UK truffle season in memory.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Y1oHSn-z-ic?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Although we are not yet sure exactly why this is the case, <a href="https://www.imperial.ac.uk/news/240391/droughts-northern-hemisphere-made-20-times/#:%7E:text=High%20temperatures%20that%20caused%20widespread,worst%20fire%20season%20ever%20recorded.">summer drought and heat</a> can be detrimental to truffle harvests. And we saw this in the south and east of England, with high temperatures, little rainfall and reduced truffle production. </p>
<p>But in the north and west of England, where rainfall is typically higher and temperatures are cooler, the impact on truffle production was very different – with truffles harvested in record quantities.</p>
<p>Not many wild truffles exist in the north and west of England, as the soil isn’t as suitable. Truffles like calcareous bedrock, such as chalk or limestone, which results in alkaline soil. So the truffle orchards in these areas have had to make the soil more alkaline by applying agricultural lime. </p>
<h2>Climate changing</h2>
<p>Perhaps then 2022 presents a good example of what we can expect, in terms of truffles in the UK as climate change advances. </p>
<p>Wild production will struggle but orchards in the south and east of England could use irrigation to sustain harvests. Meanwhile, orchards in the centre, north and west of England may be far more resilient. However, offsetting the expected decline in Mediterranean production will be almost impossible. </p>
<p>But while climate most certainly impacts the growth and development of truffles, it may also be important in terms of <a href="https://www.nbcnews.com/id/wbna40090841">reproduction</a>. Indeed, truffle fungi require two different truffle “mating types”, akin to males and females in humans, to come into contact to produce the actual fruiting bodies, much like pollination in fruit crops. </p>
<p>Although we are not totally sure how this happens, more and more <a href="https://doi.org/10.1016/j.fooweb.2022.e00260">evidence</a> indicates that invertebrates – such as the humble woodlouse – may help by eating small amounts of truffle and then moving spores (and the different mating types) which are then deposited in their faecal matter. </p>
<figure class="align-center ">
<img alt="Truffles being grated onto pasta in an expensive restaurant." src="https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513974/original/file-20230307-16-4x3z0m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How it’s done.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pasta-truffles-typical-autumn-dish-menu-1216733182"> David Tadevosian/Shutterstock</a></span>
</figcaption>
</figure>
<p>Crucially, in warmer and dryer conditions these invertebrates reduce feeding and movement, which results in fewer spores and mating types being moved around.
So this is yet another way truffle production is negatively impacted by hotter and dryer conditions. </p>
<p>But climate change has also led to some unexpected benefits, too. In 2017, <a href="https://www.finefoodspecialist.co.uk/perigord-black-truffle-tuber-melanosporum-fresh">Périgord truffles</a> (<em>Tuber melanosporum</em>) which are native to southern Europe and some of the most expensive truffles in the world, were grown for the first <a href="https://www.cam.ac.uk/research/news/perigord-black-truffle-cultivated-in-the-uk-for-the-first-time">time in Wales</a>. </p>
<p>This was possible due to the change in climate that has already occurred since the onset of the industrial revolution. Temperatures have increased just enough to allow this species to fruit. </p>
<p>Advancing climate change is a huge global problem, but in terms of truffles in the UK, it can be viewed as both a threat and an opportunity. Either way, Mrs Beeton would likely be happy to see the local truffle industry finally unearthed, once more.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Paul W Thomas works for Mycorrhizal Systems Ltd and is Honorary Professor at the University of Stirling. </span></em></p>Truffles are one of the world’s most expensive foods and climate crisis is changing the way they grow.Paul W Thomas, Honorary Professor Department of Biological and Environmental Sciences, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2004282023-03-07T13:43:36Z2023-03-07T13:43:36ZPancakes won’t turn you into a zombie as in HBO’s ‘The Last of Us,’ but fungi in flour have been making people sick for a long time<figure><img src="https://images.theconversation.com/files/513212/original/file-20230302-18-uldpy1.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1198%2C628&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A human fungal zombie from the TV show 'The Last of Us.'</span> <span class="attribution"><a class="source" href="https://imgix.bustle.com/uploads/image/2023/1/20/2c922756-5f33-430d-801b-995eec7dc0d1-the-last-of-us.jpg?w=1200&h=630&fit=crop&crop=faces&fm=jpg">Liane Hentscher/HBO</a></span></figcaption></figure><p>In the HBO series “<a href="https://www.hbo.com/the-last-of-us">The Last of Us</a>,” named after the popular video game of the same name, the flour supplies of the world are contaminated with a fungus called <em>Cordyceps</em>. When people eat pancakes or other foods made with that flour, the fungi grow inside their bodies and turn them into zombies. </p>
<p>As a <a href="https://scholar.google.com/citations?user=5iZjEckAAAAJ&hl=en&oi=ao">food scientist</a>, I study the effect of processing on the quality and safety of fruits and vegetables, including the flour used to make pancakes. While no one is going to turn into a zombie from eating pancakes in real life, flour is often contaminated with fungi that can produce mycotoxins that make people sick. Proper processing and cooking, however, can generally keep you safe. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/uLtkt8BonwM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">‘The Last of Us’ is premised on a pandemic that brings the world to an apocalyptic collapse.</span></figcaption>
</figure>
<h2>How common is fungi in flour?</h2>
<p>People have been eating bread made from wheat for <a href="https://www.bbc.com/news/science-environment-44846874">approximately 14,000 years</a> and cultivating wheat for <a href="https://sustainablefoodtrust.org/news-views/a-brief-history-of-wheat/">at least 10,000 years</a>. In 1882, “<a href="https://doi.org/10.7717%2Fpeerj.12346">drunken bread disease</a>” was first documented in Russia, where people reported dizziness, headache, trembling hands, confusion and vomiting after eating bread. Long before that, Chinese peasants were reporting that eating pinkish wheat – a key sign of infection with a mold called <em>Fusarium</em> – caused them to feel ill. Clearly, fungi have been making people sick for a long time.</p>
<p>Wheat, corn, rice and even fruits and vegetables can be infected with fungi as they grow in the field. In “The Last of Us,” an epidemiologist theorizes that climate change is causing the fungus to mutate so it can infect humans. The unfortunate reality is that fungi have become more of a problem in recent years as <a href="https://doi.org/10.3389/fcimb.2018.00060">warmer temperatures</a> encourage their growth. </p>
<p><a href="https://doi.org/10.1111/jfs.12422">A 2017 study</a> found that over 90% of wheat and corn flour samples in Washington, D.C., contained live fungi, with <em>Aspergillus</em> and <em>Fusarium</em> the predominant types of mold in wheat flour. <em>Fusarium</em> grows on wheat in the field and can cause a common agricultural plant disease called <a href="https://ahdb.org.uk/knowledge-library/fusarium-and-microdochium-in-cereals">fusarium head blight</a>, or scab. </p>
<p>Farmers use <a href="https://open.alberta.ca/publications/fusarium-head-blight-of-barley-and-wheat">multiple techniques</a> to reduce this devastating plant disease, including implementing crop rotation, using resistant varieties and fungicides and minimizing irrigation during flowering. After harvesting, they sort the grains to remove contaminated wheat before grinding them into flour. While sorting removes most of the contaminated wheat, small amounts of fungi can still make it into the flour.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Pink wheat stalks infected with fusarium head blight" src="https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513399/original/file-20230303-29-cz1zd4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Wheat infected with fusarium head blight have a characteristic pink hue.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/fusarium-ear-blight-fusarium-head-blight-fhb-or-royalty-free-image/1358429685">Tomasz Klejdysz/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>Killing microorganisms in flour</h2>
<p>The good news is that most fungi and other microorganisms <a href="https://www.ars.usda.gov/ARSUserFiles/60701000/FoodSafetyPublications/p328.pdf">die at 160-170 degrees Fahrenheit</a> (71-77 degrees Celsius). Pancakes are typically cooked to an internal temperature of <a href="https://www.lafujimama.com/oven-baked-pancake/">190-200 F</a> (88-93 C). Other cakes and breads are cooked to internal temperatures <a href="https://blog.thermoworks.com/bread/baked-good-doneness-temps/">anywhere from 180 to 210 degrees Fahrenheit</a> (82-99 C). So, unlike in “The Last of Us,” as long as you bake or fry your dough, you’ll have killed the fungi.</p>
<p>The problem comes when people eat the flour without cooking it first, such as by consuming raw cookie dough or “licking the bowl clean.” Both raw egg and raw flour can contain microorganisms that make people sick. The microorganisms that public health officials are most worried about are <a href="https://www.cdc.gov/foodsafety/communication/ecoli-and-food-safety.html"><em>E. coli</em></a> and <a href="https://www.cdc.gov/foodsafety/communication/salmonella-food.html"><em>Salmonella</em></a>, dangerous pathogens that can cause severe illness. </p>
<p>Most people don’t realize that the flour they buy at the store is raw flour that still contains live microorganisms. Flour is rarely commercially treated to be safe to eat raw because consumers almost always cook flour-based foods. While consumers can also attempt to heat-treat raw flour at home, <a href="https://ag.purdue.edu/stories/home-kitchen-heat-treated-flour-doesnt-protect-against-foodborne-illnesses-purdue-food-scientist-says/">this isn’t recommended</a> because the flour may not be spread thinly enough to kill all of the microorganisms.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of _Aspergillus_" src="https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513408/original/file-20230303-20-m292l6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"><em>Aspergillus</em> is one of the predominant molds found in wheat flour.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/aspergillus-under-the-light-microscopic-view-for-royalty-free-image/1332594729">tonaquatic/iStock via Getty Images Plus</a></span>
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<p>Some fungi and microorganisms can create spores, which are like seeds that help them survive adverse conditions. These spores can survive cooking, drying and freezing. There are even <a href="https://www.smithsonianmag.com/smart-news/bread-was-made-using-4500-year-old-egyptian-yeast-180972842/">4,500-year-old yeast spores</a> that have been reawakened and made into bread. These fungal spores rarely cause serious illness in people, except in those with <a href="https://doi.org/10.1101%2Fcshperspect.a019273">weakened immune systems</a>.</p>
<p><a href="https://doi.org/10.3390%2Fmicroorganisms5030037">Chemicals can be added to food</a> to stop fungal growth. These additives include sorbates, benzoates and propionates. However, you almost never see these additives in flour or pancake mix because fungi can’t grow in a dry powder. The fungi either grew on the wheat in the field or on the bread after it is baked. For that reason, you may see these additives in bread but not in a powdered mix.</p>
<h2>Mycotoxins</h2>
<p>The biggest risk from fungi is not that it will grow inside our bodies, but that it will grow on wheat or other foods and produce <a href="https://doi.org/10.5487%2FTR.2019.35.1.001">chemicals called mycotoxins</a> that can cause severe health problems. When wheat is harvested and ground into flour, mycotoxins can get mixed in. </p>
<p>Unfortunately, while normal cooking can kill the microorganisms, it <a href="https://doi.org/10.5487%2FTR.2019.35.1.001">doesn’t destroy the mycotoxins</a>. Eating mycotoxins can cause problems ranging from hallucinations to vomiting and diarrhea to cancer or death. Some of the <a href="https://doi.org/10.1111/jfs.12422">common mycotoxins</a> found in grain include aflatoxins, deoxynivalenol, ochratoxin A and fumonisin B.</p>
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<a href="https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Moldy pastry on a plate" src="https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513410/original/file-20230303-22-5r5j15.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">It might be best to leave that moldy bread alone.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/moldy-inedible-spoiled-food-pasty-with-mold-in-a-royalty-free-image/1167797155">Yulia Naumenko/Moment via Getty Images</a></span>
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<p>The oldest known case of mycotoxin poisoning is recorded as a <a href="https://doi.org/10.1021/acs.jafc.6b04494">disease called ergotism</a>. Ergotism was mentioned in the Old Testament and has been reported in Western Europe since A.D. 800. It has even been suggested that the <a href="https://www.vox.com/2015/10/29/9620542/salem-witch-trials-ergotism">Salem witch trials</a> were caused by an outbreak of ergotism that led its victims to hallucinate, though many have disputed this idea. Wheat is <a href="https://doi.org/10.1007/s11356-021-12671-w">less likely</a> than other grains to have dangerous mycotoxins, which is why some have proposed that declining mortality in 18th-century Europe, <a href="https://doi.org/10.1017/s0025727300034116">especially in England</a>, was due to the switch from a rye-based diet to a wheat-based diet.</p>
<p>Ultimately, you don’t need to worry about eating those pancakes. Farmers use many techniques to minimize fungal growth and remove moldy grain, and the government keeps a close eye on mycotoxin levels during crop production and storage. Just make sure you cook your bakery products before eating, and don’t eat anything that has started to mold.</p><img src="https://counter.theconversation.com/content/200428/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sheryl Barringer does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Raw flour at the store still contains live microorganisms. And while cooking can kill the fungi, it doesn’t destroy any illness-causing mycotoxins that might be present.Sheryl Barringer, Professor of Food Science and Technology, The Ohio State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2002712023-02-26T23:55:22Z2023-02-26T23:55:22ZThis freaky slime mould from HBO’s The Last of Us isn’t a fungus at all – but it is a brainless predator<figure><img src="https://images.theconversation.com/files/512123/original/file-20230224-16-zaem1b.jpg?ixlib=rb-1.1.0&rect=0%2C38%2C2823%2C2074&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Slime mould navigating a food grid.</span> <span class="attribution"><span class="source">Chris R. Reid/Macquarie University</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In HBO’s post-apocalyptic drama The Last of Us, human civilisation has fallen in the face of a fungal takeover triggered by climate change.</p>
<p>The show’s opening credits and creature designs are inspired by the slime mould <em>Physarum polycephalum</em>. But while the show’s “infected” (i.e. zombies) are meant to be victims of a fungal pandemic, slime moulds are not actually fungi at all.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/8SWhBsbxmpk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Opening credits for The Last of Us. HBO Max/YouTube.</span></figcaption>
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<p>They are in fact much more ancient, and less closely related to fungi than even we are. Since scientists first tried to classify slime moulds, they have been wrongly grouped with plants, animals, and in particular, fungi. </p>
<p>This is because they typically occur in the same ecosystems as fungi, and because they produce structures to help spread their spores, much like their fungal cousins do. </p>
<p>Molecular methods for grouping lifeforms by comparing their DNA have helped us better understand slime moulds’ distinct heritage. Yet their exact place on the tree of life is still unclear. </p>
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Read more:
<a href="https://theconversation.com/before-the-last-of-us-i-was-part-of-an-international-team-to-chart-the-threat-of-killer-fungi-this-is-what-we-found-199593">Before The Last of Us, I was part of an international team to chart the threat of killer fungi. This is what we found</a>
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<h2>A fierce predator</h2>
<p>Despite bearing a superficial similarity to fungi, there are many aspects of the slime mould’s biology that are strikingly unique. This yellow blob of goo may not look like much, but it is in fact a fierce predator of bacteria, yeasts and other microorganisms, including fungi. </p>
<p>Though they can grow quite large – up to several square metres across – each slime mould is a single cell, containing millions of nuclei and all the other complex machinery that lies inside cells like ours.</p>
<p>The slime mould’s “body” is a network of veins and tubes that can move at the rapid pace of up to five centimetres per hour to locate and capture their prey.</p>
<p>Inside the slime mould, a rich soup of cell components and food particles flows back and forth within the network. This flow transmits nutrients, chemical signals and information between different regions of the slime mould.</p>
<p>These rippling, sprawling movements are likely what makes slime mould so appealingly creepy to horror artists and filmmakers.</p>
<figure class="align-center ">
<img alt="A prosthetic humanoid corpse against a brick wall, with orange bracket fungi growing from the skin and network-like yellow material spreading out from the body onto the wall." src="https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/511608/original/file-20230222-18-uj248q.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=605&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">In this behind the scenes shot, one of ‘the infected’ from HBO’s The Last of Us is plastered to the wall by what looks like giant slime moulds.</span>
<span class="attribution"><a class="source" href="https://www.instagram.com/p/CnfLqb9KGYL/">@barriegower/Instagram</a></span>
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Read more:
<a href="https://theconversation.com/the-last-of-us-fungal-infections-really-can-kill-and-theyre-getting-more-dangerous-198184">The Last of Us: fungal infections really can kill – and they’re getting more dangerous</a>
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<h2>Zombie intelligence</h2>
<p>Slime mould physiology and anatomy is as alien as it is fascinating. But it’s their behaviour that separates them from their peers, and perhaps mirrors our own a little too closely for comfort. </p>
<p>Far from being simple cells moving blindly through the leaf litter, slime moulds can gather a huge amount of information from their environment, and use it to make smart decisions about where to move and look for food, much like the infected in The Last of Us, which operate as one large organism in search of prey. </p>
<p>So far, the slime mould has been shown to sense and move toward or away from <a href="https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-108-1-17">carbohydrates</a>, proteins, <a href="https://www.sciencedirect.com/science/article/pii/0014482778904615">amino acids</a>, <a href="https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-102-1-145">free nucleotides</a>, <a href="https://www.tandfonline.com/doi/full/10.4161/cib.28543">volatile organic chemicals</a>, <a href="https://www.sciencedirect.com/science/article/pii/0301462280870232">salts</a>, pH, light, humidity and <a href="https://europepmc.org/article/med/943401">temperature</a>, even sensing the direction of <a href="https://www.sciencedirect.com/science/article/pii/0309165187900142">gravity</a> and <a href="https://ieeexplore.ieee.org/abstract/document/6505318">magnetic fields</a>.</p>
<p>When a slime mould finds several food sources at the same time, it tries to cover each food with as much of itself as it can (to absorb it), without splitting into disconnected individuals. The most efficient way to do this is to have a single tube connecting the two foods along the shortest path between them. </p>
<p>Slime moulds have evolved over millions of years to become master network engineers. They are expert <a href="https://www.nature.com/articles/35035159">maze-solvers</a>, and researchers have begun to build computer algorithms for the design of <a href="https://www.science.org/doi/full/10.1126/science.1177894">human train and telecommunication networks based on slime mould approaches</a>. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/HkM7FjmJ5dM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The yellow blob of goo is a single network (and single cell) of Physarum polycephalum exploring the surface of an agar plate in search of food. The footage is sped up significantly (around 20x). Chris R. Reid/New Jersey Institute of Technology.</span></figcaption>
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Read more:
<a href="https://theconversation.com/the-brainless-slime-mould-that-remembers-where-its-been-10015">The brainless slime mould that remembers where it's been</a>
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<h2>No brain? No problem</h2>
<p>Slime moulds’ problem-solving abilities are all the more fascinating because the creature doesn’t have a brain or even a single neuron. Nevertheless, they show signs of memorisation and even learning – two things which traditionally were thought possible only in animals with brains.</p>
<p>As they move, slime moulds leave behind a trail of slime similar to mucous. This slime trail serves as an <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1215037109">externalised memory</a> of areas it has explored in the past, which is very useful for solving mazes.</p>
<p>They can distinguish between their own trails, their neighbours’, and those of <a href="https://academic.oup.com/beheco/article/24/4/812/220539">other slime mould species</a>. They also use food signals left behind in the trails to <a href="https://royalsocietypublishing.org/doi/full/10.1098/rstb.2019.0470">judge their own chances of finding food in an area</a>.</p>
<p><a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2016.0446">Researchers have also found</a> slime moulds can learn to ignore a substance they normally find repellent (such as quinine or caffeine) after prolonged exposure. Researchers call this basic form of learning “habituation”.</p>
<p>Amazingly, when a habituated slime mould fuses together with an untrained slime mould (oh yeah, they can do that), <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2016.2382">the learned behaviour is observed in the new combined individual</a>.</p>
<p>All this raises the (somewhat creepy) question: what other kinds of knowledge do slimy creatures pass between each other as they crawl beneath the forest floor?</p>
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Read more:
<a href="https://theconversation.com/natures-traffic-engineers-have-come-up-with-many-simple-but-effective-solutions-94818">Nature's traffic engineers have come up with many simple but effective solutions</a>
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<img src="https://counter.theconversation.com/content/200271/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris R. Reid receives funding from the Australian Research Council.</span></em></p>Slime moulds feature throughout HBO’s The Last of Us. While they aren’t a true fungus, they do have a lot in common with zombies.Chris R. Reid, ARC Future Fellow, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.