tag:theconversation.com,2011:/ca/topics/biofilms-56174/articlesBiofilms – The Conversation2023-12-19T18:13:36Ztag:theconversation.com,2011:article/2146882023-12-19T18:13:36Z2023-12-19T18:13:36ZShipwrecks teem with underwater life, from microbes to sharks<figure><img src="https://images.theconversation.com/files/555600/original/file-20231024-25-xo8h4f.jpg?ixlib=rb-1.1.0&rect=30%2C15%2C5061%2C3534&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A school of grunts on a sunken World War II German submarine in the Atlantic Ocean off North Carolina.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/diver-and-schooling-tomtates-on-wwii-u-352-german-royalty-free-image/153943111">Karen Doody/Stocktrek Images via Getty Images</a></span></figcaption></figure><p>Humans have sailed the world’s oceans for thousands of years, but they haven’t all reached port. Researchers estimate that there are <a href="https://unesdoc.unesco.org/ark:/48223/pf0000152883">some three million shipwrecks</a> worldwide, resting in shallow rivers and bays, coastal waters and the deep ocean. Many sank during catastrophes – some during storms or after running aground, others in battle or collisions with other vessels.</p>
<p>Shipwrecks like <a href="https://www.britannica.com/topic/Titanic">the RMS Titanic</a>, <a href="https://www.britannica.com/topic/Lusitania-British-ship">RMS Lusitania</a> and <a href="https://www.britannica.com/technology/monitor-ship-type#ref51448">USS Monitor</a> conjure tales of human courage and sacrifice, sunken treasure and unsolved mysteries. But there’s another angle to their stories that doesn’t feature humans. </p>
<p>I have <a href="https://scholar.google.com/citations?user=wZ-kv2AAAAAJ&hl=en">studied the biology of shipwrecks</a> in the United States and internationally for 14 years. From this work, I have learned that shipwrecks are not only cultural icons but can also be biological treasures that create habitat for diverse communities of underwater life. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FTYyzAxt3JI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The USS Monitor, which sank off Cape Hatteras, North Carolina, in a storm on Dec. 31, 1862, is now a center for sea life.</span></figcaption>
</figure>
<p>Recently, I led an international team of biologists and archaeologists in disentangling the mysteries of how this transformation happens. Drawing on scientific advances from our team and international colleagues, our <a href="https://academic.oup.com/bioscience/article-lookup/doi/10.1093/biosci/biad084">new study</a> describes how wrecked vessels can have second lives as seabed habitats.</p>
<h2>A new home for underwater life</h2>
<p>Ships are typically made of metal or wood. When a vessel sinks, it adds foreign, artificial structure to the seafloor. </p>
<p>For example, the World War II tanker <a href="https://monitor.noaa.gov/shipwrecks/clark.html">E.M. Clark</a> sank on a relatively flat, sandy seabed in 1942 when it was torpedoed by a German submarine. To this day, the intact metal wreck looms over the North Carolina seafloor like an underwater skyscraper, creating an island oasis in the sand. </p>
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<figcaption><span class="caption">In this video narrated by NOAA research scientist Avery Paxton, sand tiger sharks hover above the wreck of the E.M. Clark off North Carolina, with vermilion snapper schooling nearby. Jacks and an invasive lionfish also appear.</span></figcaption>
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<p>The creatures that reside on and around sunken ships are so diverse and abundant that scientists often colloquially call these sites “<a href="https://3d-shipwreck-data-viewer-noaa.hub.arcgis.com/">living shipwrecks</a>.” Marine life ranging from microscopic critters to some of the largest animals in the sea use shipwrecks as homes. Brilliantly colored corals and sponges blanket the wrecks’ surfaces. Silvery schools of baitfish dart and shimmer around the structures, chased by sleek, fast-moving predators. Sharks sometimes cruise around wrecks, likely resting or looking for prey. </p>
<h2>The origin of a second life</h2>
<p>A ship’s transformation from an in-service vessel into a thriving metropolis for marine life can seem like a fairy tale. It has a once-upon-a-time origin story – the wrecking event – and a sequence of life arriving on the sunken structure and beginning to blossom.</p>
<p>Tiny microbes invisible to the naked human eye initially settle on the wreck’s surface, forming a carpet of cells, called a <a href="https://www.britannica.com/science/biofilm">biofilm</a>. This coating helps to <a href="https://doi.org/10.3389/fmars.2019.00048">make the wreck structure suitable</a> for larval animals like sponges and corals to settle and grow there.</p>
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<a href="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Shellfish, deepwater coral and anemones cling to the surface of a sunken wreck." src="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555611/original/file-20231024-23-oqeoj2.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>
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<span class="caption">Diverse sea creatures living on the 19th-century, wooden-hulled Ewing Bank wreck, which lies 2,000 feet (610 meters) deep in the Gulf of Mexico.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/19microbial-stowaways/background/archaeology/media/img2-hires.jpg">NOAA</a></span>
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<p>Larger animals like fish sometimes appear within minutes after a ship sinks. <a href="https://coastalscience.noaa.gov/news/artificial-reefs-may-help-tropical-fish-expand-geographic-range-video/">Small fish</a> hide in the structure’s cracks and crevices, while <a href="https://doi.org/10.1016/j.fooweb.2020.e00147">large sharks</a> glide around it. <a href="https://doi.org/10.1016/j.marenvres.2020.104916">Sea turtles</a> and marine mammals such as <a href="https://doi.org/10.1371/journal.pone.0130581">fur seals</a> have also been spotted on wrecks.</p>
<h2>Hot spots for biodiversity</h2>
<p>Shipwrecks host quantities and varieties of marine life that can make them hot spots for biodiversity. The microbes that transform the wreck structure into habitat also enrich the surrounding sand. Evidence from deep Gulf of Mexico wrecks shows that a <a href="https://doi.org/10.1038/s41396-021-00978-y">halo of increased microbial diversity</a> radiates outward anywhere from 650 to 1,000 feet (200-300 meters) from the wreck. In the Atlantic Ocean, <a href="https://doi.org/10.1111/faf.12548">thousands of grouper</a>, a type of reef fish highly valued by fishers, congregate around and inside shipwrecks.</p>
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<a href="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Fish hover above a wrecked ship's surface." src="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555613/original/file-20231024-29-aaqe3w.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">Groupers and a conger eel, bottom center, on the wreck of the German submarine U-576 off the coast of North Carolina.</span>
<span class="attribution"><a class="source" href="https://oceanexplorer.noaa.gov/explorations/16battlefield/logs/sept7/sept7.html">NOAA</a></span>
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<p>Shipwrecks can also serve as stepping stones across the ocean floor that animals use as temporary homes while moving from one location to another. This has been documented in areas of the world with dense concentrations of shipwrecks, such as off North Carolina, where storms and war have sunk hundreds of ships.</p>
<p>In this part of the ocean, popularly known as the “<a href="https://www.ncpedia.org/graveyard-atlantic">Graveyard of the Atlantic</a>,” reef fish likely <a href="https://doi.org/10.1038/s42003-019-0398-2">use the islandlike shipwrecks as corridors</a> when moving north or south away from the equator to find favorable water temperatures as climate change <a href="https://theconversation.com/ocean-heat-is-at-record-levels-with-major-consequences-174760">warms the oceans</a>. Scientists have also observed <a href="https://doi.org/10.1002/ecy.2687">sand tiger sharks</a> traveling from one wreck to another, possibly using the shipwrecks like rest stops during migration.</p>
<p>In the deep sea, life growing on shipwrecks can even generate energy. Tube worms that grow on organic shipwreck materials such as paper, cotton and wood host symbiotic bacteria that produce chemical energy. Such tube worm colonies have been documented in the Gulf of Mexico on the steel <a href="https://www.boem.gov/sites/default/files/boem-newsroom/Library/Ocean-Science/Ocean-Science-Jul-Aug-Sep-2014.pdf">luxury yacht Anona</a>. </p>
<h2>Biological mysteries abound</h2>
<p>Despite their biological value, shipwrecks can also threaten underwater life by altering or destroying natural habitats, causing pollution and spreading invasive species.</p>
<p>When a ship sinks, it can damage existing seafloor habitats. In a well-documented case in the Line Islands of the central Pacific, an <a href="https://doi.org/10.1038/ismej.2011.114">iron shipwreck</a> sank on a healthy coral reef. The iron infusion substantially decreased coral cover, and the reef was overcome by algae.</p>
<p>Ships may carry pollutants as fuel or cargo. As shipwrecks deteriorate in seawater, there is a risk that these pollutants may be released. The <a href="https://doi.org/10.1016/j.marpolbul.2021.112087">level of risk</a> depends on how much of the pollutant the ship was carrying and how intact the wreck is. One recent investigation revealed that effects from shipwreck pollutants can be detected in microbes up to <a href="https://doi.org/10.3389/fmars.2022.1017136">80 years after the wreck</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/JTq4b9c3Z00?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Ships and planes wrecked in wartime can leak toxic materials for decades after they come to rest in the ocean.</span></figcaption>
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<p>Shipwrecks may also inadvertently assist the spread of invasive plants and animals that wreak biological havoc. Wrecks are new structures that invasive species can settle on, grow and use as a hub to expand to other habitats. <a href="https://doi.org/10.1016/j.marpolbul.2020.111394">Invasive cup coral</a> has spread on World War II shipwrecks off Brazil. In Palmyra Atoll in the Pacific, a type of anemone called a corallimorph <a href="https://doi.org/10.1371/journal.pone.0002989">rapidly invaded</a> a shipwreck and now <a href="https://doi.org/10.1007/s10530-018-1696-1">threatens healthy coral reefs</a>.</p>
<h2>The future of shipwreck exploration</h2>
<p>Shipwrecks create millions of study sites that scientists can use to ask questions about marine life and habitats. One of the greatest challenges is that many wrecks are undiscovered or in remote locations. Advances in technology can help researchers see into the most inaccessible areas of the ocean, not only to find shipwrecks but to better understand their biology. </p>
<p>Maximizing discovery will require biologists, archaeologists and engineers to work together to explore these special habitats. Ultimately, the more we learn, the more effectively we can conserve these historical and biological gems.</p><img src="https://counter.theconversation.com/content/214688/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Avery Paxton is affiliated with NOAA National Centers for Coastal Ocean Science. </span></em></p>When ships sink, they add artificial structures to the seafloor that can quickly become diverse, ecologically important underwater communities.Avery Paxton, Research Marine Biologist, National Oceanic and Atmospheric AdministrationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2113562023-10-15T23:27:42Z2023-10-15T23:27:42ZSlime after slime: why those biofilms you slip on in rivers are vitally important<figure><img src="https://images.theconversation.com/files/543180/original/file-20230817-5739-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>You might have noticed it after sliding on a rock in a Melbourne creek. Or it could have been wading through a Northern Territory waterhole. It’s slime, and our rivers are full of it. That’s a good thing. </p>
<p>Wherever there are hard surfaces like snags and rocks in our rivers, you’ll find slime. Or, as ecologists call it, <a href="https://en.wikipedia.org/wiki/Biofilm">biofilm</a>. Biofilms consist of communities of microorganisms that include algae, cyanobacteria, bacteria, fungi and protozoa. Together, they’re fixed in a matrix of natural polymers made by bacteria and other tiny creatures. It’s this matrix which gives the slippery, slimy texture we encounter when swimming in rivers. </p>
<p>Biofilms play an important role in our freshwater ecosystems. They underpin healthy rivers by forming the base of freshwater <a href="https://flow-mer.org.au/basin-theme-food-webs-water-quality/">food webs</a>. </p>
<p>Our <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.4680">new research</a> explores how these common but unsung communities change over time. We found that biofilms are most nutritious when new – less than six weeks old. After that, their food value declines. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="biofilm and algae from river" src="https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543184/original/file-20230817-28-xdh60x.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">This is what a 73-day-old biofilm looks like after being pulled from a lowland river.</span>
<span class="attribution"><span class="source">Author provided</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why are biofilms important?</h2>
<p>Without slime, rivers would lack a fundamental source of food for animals. That sounds like a big statement, but <a href="https://onlinelibrary.wiley.com/doi/full/10.1046/j.1442-8903.2001.00069.x">it’s true</a>. </p>
<p>Algae take energy from the sun and convert it into new biomass through <a href="https://education.nationalgeographic.org/resource/photosynthesis/">photosynthesis</a>. Bacteria and fungi break down organic debris, from dead leaves to dead fish, and recycle the nutrients. Tiny invertebrate grazers such as <a href="https://en.wikipedia.org/wiki/Zooplankton">zooplankton</a> and <a href="https://www.mdfrc.org.au/bugguide/">macroinvertebrates</a> feed on biofilms. In turn, they become food for larger predators such as fish, platypus and turtles. </p>
<p>Not all biofilms offer the same quality of food. And different communities of biofilm grow under different physical conditions.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/life-on-earth-was-nothing-but-slime-for-a-boring-billion-years-23358">Life on Earth was nothing but slime for a 'boring billion' years
</a>
</strong>
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<p>When the water level goes up in a river, rocks and dead trees at the surface are submerged and biofilms colonise this new habitat. It happens very quickly. Bacteria arrive first, followed by algae in the next few weeks. </p>
<p>Biofilms undergo natural changes in community composition over time, influenced by physical disturbance (such as scouring when water flow is high, or sedimentation from low flows) or chemical changes, such as additional nutrients from runoff. </p>
<p>These disturbances often lead to periods of collapse and recolonisation by new organisms. Biofilms are thought to become a poorer source of food for animals as they get older. That’s because older biofilm communities become dominated by <a href="https://en.wikipedia.org/wiki/Cyanobacteria">cyanobacteria</a> and <a href="https://en.wikipedia.org/wiki/Spirogyra">filamentous algae</a>, which aren’t as nutritious as a food for animals.</p>
<h2>So what makes good slime?</h2>
<p>For the discerning invertebrate, the best biofilm is one containing lots of algae – especially <a href="https://en.wikipedia.org/wiki/Diatom">diatoms</a> and green algae. These are rich sources of <a href="https://onlinelibrary.wiley.com/doi/10.1111/brv.13017">omega 3 fatty acids</a>, molecules essential for animal growth and reproduction. (That’s why the food supplement industry likes to sell us products rich in omega 3s). </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="mayfly nymphs" src="https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=843&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=843&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550505/original/file-20230927-23-nmf7ax.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=843&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mayfly nymphs, such as this <em>Offadens</em> spp. (Baetidae) scrape algae and fine detritus from submerged rocks, wood and macrophytes in rivers.</span>
<span class="attribution"><span class="source">Chris Davey</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Having high quality food is one thing. But the food also needs to be easy to get. In the study of food webs, we often use a theory called <a href="https://encyclopedia2.thefreedictionary.com/ecological+energetics">ecological energetics</a>. Put simply, this suggests the success of an animal population is limited by how hard it is for individuals to obtain sufficient <a href="https://onlinelibrary.wiley.com/doi/10.1111/fwb.13895">food for growth</a> and reproduction. </p>
<p>You might have long-chain omega 3 fatty acids present, but buried under a pile of less edible microorganisms and detritus. The effort may simply not be worth the reward. </p>
<p>To date, we have a poor understanding of when biofilms hit their peak food value for animals. That’s what we set out to find. </p>
<h2>What did we find?</h2>
<p>Many of our rivers are regulated by dams and weirs. That means we can alter water levels to cover rocks and snags with water and trigger growth of new biofilms. </p>
<p>If we know how long it takes for biofilms to reach optimum quality, we can manage water levels to improve food value and benefit both biofilm grazers and the fish that eat them. </p>
<p>In our study, we sank wooden redgum blocks 20 centimetres under the surface of three rivers. Then we sampled the biofilm for 73 days, taking DNA to assess how the proportions of algae, cyanobacteria and fungi varied over time. </p>
<p>We developed a novel approach to assess food value, accounting for both quality of fatty acid profiles and their availability in space.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543181/original/file-20230817-29-v86h6h.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">
<figcaption>
<span class="caption">Redgum blocks give biofilm communities something to grow on.</span>
</figcaption>
</figure>
<p>What did we find? Food value for animals peaked between 24 and 43 days after the blocks were submerged.</p>
<p>After 43 days, the food value of biofilms declined. Filamentous algae and cyanobacteria numbers increased as the biofilms aged, while green algae and diatoms abundance decreased. The amount of slimy-feeling natural polymers also increased over time, making our once-delicious biofilms even less nutritious.</p>
<p>So what does this mean? Water agencies are increasingly using environmental flows to support freshwater fish and animal populations. A widely used application for environmental water is to raise water levels in rivers and weirs to inundate new hard surfaces to grow new biofilms.</p>
<p>Now we know that after six weeks the food value of biofilms for animals declines – and that can help managers find the best ways of using environmental water to produce a biofilm bonanza for invertebrates and everything that eats them.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/unlocking-the-secrets-of-bacterial-biofilms-to-use-against-them-59148">Unlocking the secrets of bacterial biofilms – to use against them</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/211356/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul McInerney receives funding from the Murray Darling Basin Authority and the Commonwealth Environmental Water Office. </span></em></p>Slime gets a bad name in popular culture, but it’s food for invertebrates who become food for many other creatures.Paul McInerney, Senior Research Scientist, CSIROLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2046562023-05-26T12:27:10Z2023-05-26T12:27:10ZDrilling down on treatment-resistant fungi with molecular machines<figure><img src="https://images.theconversation.com/files/523869/original/file-20230502-26-xj4lbv.jpg?ixlib=rb-1.1.0&rect=19%2C12%2C2098%2C1387&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Newly developed molecular drills may be able to fight treatment-resistant fungal infections like *Candida auris*.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/candida-auris-fungi-emerging-multidrug-resistant-royalty-free-image/1028379354?phrase=Candida%20auris%20fungi%2C%20emerging%20multidrug%20resistant%20fungus">Dr_Microbe/iStock via Getty Images</a></span></figcaption></figure><p>Fungi are present on the skin of around 70% of the population, without causing harm or benefit. Some fungal infections, like athlete’s foot, are minor. Others, like <em>Candida albicans</em>, can be deadly – especially for individuals with <a href="https://doi.org/10.1038/s41577-022-00826-w">weakened immune systems</a>. </p>
<p><a href="https://doi.org/10.1086/322685">Fungal infections are on the rise</a> because of an aging population and an increased prevalence of chronic diseases. At the same time, fungi are becoming <a href="https://doi.org/10.1038/s41579-022-00720-1">more resistant to treatment</a>. As a result, fungal infections could soon become a serious public health threat.</p>
<p>In 2022, the World Health Organization released its first-ever “<a href="https://www.who.int/publications/i/item/9789240060241">Fungal Priority Pathogen List</a>,” calling for improved surveillance, public health interventions and the development of new antifungal drugs. </p>
<p>We are an <a href="https://www.jmtour.com/">interdisciplinary team</a> of <a href="https://scholar.google.com/citations?user=7g-Vv80AAAAJ&hl=en&oi=sra">chemists</a> and <a href="https://scholar.google.com/citations?user=adrn7L0AAAAJ&hl=en">biologists</a> charting a new path to tackle drug-resistant infections. We are using tiny nanoscale drills that combat harmful pathogens at the molecular level. As the traditional antimicrobial research pipeline struggles, our approach has the potential to rejuvenate the fight against these stubborn infections.</p>
<h2>Molecular machines as alternative antifungals</h2>
<p>While doctors urgently need new antifungal drugs, <a href="https://doi.org/10.1101/cshperspect.a019703">developing them is challenging</a>. First, it is difficult to develop drugs that selectively kill fungi without harming human cells because of their <a href="https://doi.org/10.2174/1389557516666160118112103">many similarities</a>.</p>
<p>Second, fungi can <a href="https://www.cdc.gov/fungal/antifungal-resistance.html">rapidly develop resistance to multiple antifungal drugs at once</a> when medications are misused or overused. As such, developing antifungal drugs is much less rewarding for drug companies than developing medications for chronic conditions like diabetes and hypertension that require long-term use.</p>
<p>One solution to this problem could lie in a <a href="https://www.nobelprize.org/prizes/chemistry/2016/summary/">Nobel Prize-winning technology</a>: molecular machines.</p>
<p>Molecular machines are synthetic compounds that rapidly rotate their components at about 3 million times per second when exposed to light. Doctors can use a light-tipped probe to activate these molecular machines to treat internal infections, or a lamp for skin infections. The light starts the machines spinning, and that rotational motion pushes them to drill through and puncture the cell’s membranes and organelles, which results in cell death. </p>
<p>Our group first used <a href="https://doi.org/10.1038/nature23657">this technology to kill cancer cells</a> in 2017. To target the right cells, molecular machines can be linked to specific peptides that bind only to the desired cells, allowing, for instance, the <a href="https://doi.org/10.1038/nature23657">targeting of specific cancer types</a>. Since then, we have used these molecules to <a href="https://doi.org/10.1126/sciadv.abm2055">kill bacteria</a>, <a href="https://doi.org/10.1021/acsami.9b22595">destroy tissue</a> and <a href="https://doi.org/10.1101/2022.11.04.515191">stimulate muscle contraction</a>. These properties make molecular machines an <a href="https://doi.org/10.1002/advs.202205781">enticing candidate technology</a> to address the growing fungal threat.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing the structure of a molecular machine as gray lines connected in the shape of several hexagons" src="https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=581&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=581&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=581&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=730&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=730&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526327/original/file-20230515-14468-odbqrr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=730&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 3D structure of a molecular machine. The molecular machine consists of rotor (top) and stator (bottom) portions connected by a central axle. Following light activation, molecular machines rotate rapidly, drilling into fungal cells.</span>
<span class="attribution"><span class="source">Tour Lab, Rice University</span></span>
</figcaption>
</figure>
<h2>Testing antifungal molecular machines</h2>
<p>Researchers first tested the ability of light-activated molecular machines to kill fungi in <em><a href="https://www.ncbi.nlm.nih.gov/books/NBK560624/">Candida albicans</a></em>. This yeastlike fungus can cause <a href="https://doi.org/10.1155/2013/204237">life-threatening infections</a> in immunocompromised people. Compared with conventional drugs, molecular machines killed <em>C. albicans</em> much faster.</p>
<p>Subsequent studies found that molecular machines could also kill other fungi, including molds like <em><a href="https://www.ncbi.nlm.nih.gov/books/NBK482464/">Aspergillus fumigatus</a></em> and species of dermatophytes, the types of fungi that cause skin, scalp and nail infections. Molecular machines even eliminated <a href="https://doi.org/10.3389/fmed.2018.00028">fungal biofilms</a>, which are slimy, antimicrobial-resistant communities of microorganisms that stick together on surfaces and commonly cause medical device-associated infections. </p>
<p>Unlike <a href="https://www.ncbi.nlm.nih.gov/books/NBK538168/">conventional antifungals</a>, which target the fungal cell membrane or cell wall, molecular machines localize to the fungal mitochondria. Often referred to as the “<a href="https://www.ncbi.nlm.nih.gov/books/NBK9896/">powerhouses of the cell</a>,” mitochondria produce energy to power other cellular activities. When activated with visible light, molecular machines destroy the fungal mitochondria. Once the fungal cell’s mitochondria stop working, the cell loses its energy supply and dies. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two black-and-white electron microscopy images of a fungal cell. The left image shows a large, round, healthy cell, while the cell on the right is shrunken following treatment with light-activated molecular machines." src="https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524506/original/file-20230504-19-347m02.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Candida albicans</em> before and after being exposed to light-activated molecular machines. Molecular machines puncture <em>C. albicans</em>‘ cell wall and intracellular organelles, eventually killing the fungal cell.</span>
<span class="attribution"><span class="source">Matthew Meyer/Rice University.</span></span>
</figcaption>
</figure>
<p>At the same time, molecular machines also <a href="https://doi.org/10.4155/fmc-2016-0050">disrupt the tiny pumps</a> that remove antifungal agents from the cell, thus preventing the cell from fighting back. Because these molecular machines act by a mechanical instead of a chemical mechanism, fungi are unlikely to develop defenses against this treatment.</p>
<p>In lab experiments, combining light-activated molecular machines with conventional antifungal drugs also reduced the amount of fungi in <em>C. albicans</em>-infected worms and in pig nails infected with <em>Trichophyton rubrum</em>, the most common cause of <a href="https://www.ncbi.nlm.nih.gov/books/NBK8301/">athlete’s foot</a>.</p>
<h2>New frontiers for fighting fungal infections</h2>
<p>These results suggest that combining molecular machines with conventional antifungals can improve existing therapies and provide new options for treating resistant fungal strains. This strategy could also help reduce the side effects of traditional antifungals, such as gastrointestinal upset and skin reactions. </p>
<p>Fungal infection rates will likely continue to rise. As such, the need for new treatments will only become more urgent. Climate change is already causing <a href="https://doi.org/10.1371/journal.ppat.1009503">new human pathogenic fungi</a> to emerge and spread, including <a href="https://www.ncbi.nlm.nih.gov/books/NBK563297/"><em>Candida auris</em></a>. <em>C. auris</em> is often resistant to treatment and spread rapidly in health care facilities <a href="https://doi.org/10.1111/myc.13471">during the COVID-19 pandemic</a>. <a href="https://www.cdc.gov/media/releases/2023/p0320-cauris.html">According to the Centers for Disease Control and Prevention</a>, strained health care systems, overuse of immunosuppressants and misuse of antibiotics have all been implicated in <a href="https://theconversation.com/how-do-candida-auris-and-other-fungi-develop-drug-resistance-a-microbiologist-explains-203495">outbreaks of <em>C. auris</em></a>.</p>
<p>In the future, researchers could use <a href="https://doi.org/10.1038/s41586-023-05905-z">artificial intelligence</a> to create better antifungal molecular machines. By using AI to predict how different molecular machines will interact with fungi and human cells, we can develop safer and more effective antifungal molecules that specifically kill fungi without harming healthy cells.</p>
<p>Antifungal molecular machines are still in the early stages of development and are not yet available for routine clinical use. However, continuing research gives hope that these machines could one day provide better treatments for fungal infections and other infectious diseases.</p><img src="https://counter.theconversation.com/content/204656/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ana L. Santos receives funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 843116.</span></em></p><p class="fine-print"><em><span>Jacob Beckham receives funding from the National Science Foundation Graduate Research Fellowship Program. </span></em></p><p class="fine-print"><em><span>James M. Tour receives funding from the Discovery Institute and the Robert A. Welch Foundation (C-2017-20190330). Rice University owns intellectual property on the use of electromagnetic (light) activation of molecular machines for the killing of cells. This intellectual property has been licensed to a company in which James M. Tour is a stockholder, although he is not an officer or director of that company.</span></em></p>Fungal infections can be among the hardest to treat, and since the pandemic began they’ve become only more common. To prevent future antifungal resistance, scientists have developed tiny molecular drills.Ana L. Santos, Postdoctoral Fellow in Microbiology, Rice UniversityJacob Beckham, Graduate Student in Chemistry, Rice UniversityJames Tour, Professor of Chemistry, Rice UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1818242022-04-26T18:39:43Z2022-04-26T18:39:43ZDisease-causing parasites can hitch a ride on plastics and potentially spread through the sea, new research suggests<figure><img src="https://images.theconversation.com/files/459606/original/file-20220425-25-tfbr1v.png?ixlib=rb-1.1.0&rect=0%2C0%2C2310%2C1296&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The sticky biofilms that form on microplastics can harbor disease-causing pathogens and help them spread.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/sea-water-contaminated-by-micro-plastic-royalty-free-image/1036767280">Tunatura/iStock via Getty Images Plus</a></span></figcaption></figure><p>Typically when people hear about plastic pollution, they might envision seabirds with bellies full of trash or sea turtles with plastic straws in their noses. However, plastic pollution poses another threat that’s invisible to the eye and has important consequences for both human and animal health.</p>
<p><a href="https://doi.org/10.1016/j.marenvres.2016.05.012">Microplastics</a>, tiny plastic particles present in many cosmetics, can form when larger materials, such as clothing or fishing nets, break down in water. Microplastics are now widespread in the ocean and have been found in fish and shellfish, including <a href="https://doi.org/10.1016/j.envpol.2014.06.010">those that</a> <a href="https://doi.org/10.1016/j.marpolbul.2018.05.047">people eat</a>.</p>
<p>As <a href="https://scholar.google.com/citations?user=v15DbVcAAAAJ&hl=en">researchers</a> <a href="https://shapirolab.vetmed.ucdavis.edu/people/emma-zhang">studying</a> how waterborne pathogens spread, we wanted to better understand what happens when microplastics and disease-causing pathogens end up in the same body of water. In our recent study published in the journal <a href="https://doi.org/10.1038/s41598-022-10485-5">Scientific Reports</a>, we found that pathogens from land can hitch a ride to the beach on microscopic pieces of plastic, providing a new way for germs to concentrate along coastlines and travel to the deep sea.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial shot of boat floating through plastic pollution on water" src="https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459605/original/file-20220425-2721-yy4mz1.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">Microplastic pollution has negative consequences for human, animal and environmental health.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/plastic-pollution-in-the-ocean-man-cleaning-plastic-royalty-free-image/1301941387">Yunaidi Joepoet/Moment via Getty Images</a></span>
</figcaption>
</figure>
<h2>Investigating how plastics and pathogens interact</h2>
<p>We focused on three parasites that are <a href="https://www.who.int/publications/i/item/9789241563826">common contaminants</a> in marine water and seafoods: the single-celled protozoans <em>Toxoplasma gondii</em> (<em>Toxo</em>), <em>Cryptosporidium</em> (<em>Crypto</em>) and <em>Giardia</em>. These parasites end up in waterways when feces from infected animals, and sometimes people, contaminate the environment.</p>
<p><a href="https://doi.org/10.1146/annurev.publhealth.18.1.135"><em>Crypto</em> and <em>Giardia</em></a> cause gastrointestinal disease that can be deadly in young children and immunocompromised individuals. <a href="https://doi.org/10.1128/cmr.05013-11"><em>Toxo</em></a> can cause lifelong infections in people, and can prove fatal for those with weak immune systems. Infection in <a href="https://www.waterpathogens.org/book/toxoplasma-gondii">pregnant women</a> can also cause miscarriage or blindness and neurological disease in the baby. <em>Toxo</em> also infects a wide range of marine wildlife and kills endangered species, including <a href="https://doi.org/10.7589/0090-3558-39.3.495">southern</a> <a href="https://doi.org/10.1017/s0031182015001377">sea otters</a>, <a href="https://doi.org/10.1016/j.vetpar.2012.11.001">Hector’s dolphins</a> and <a href="https://doi.org/10.3354/dao03047">Hawaiian monk seals</a>.</p>
<p>To test whether these parasites can stick onto plastic surfaces, we first placed microplastic beads and fibers in beakers of seawater in our lab for two weeks. This step was important to induce the formation of a <a href="https://www.livescience.com/57295-biofilms.html">biofilm</a> – a sticky layer of bacteria and gellike substances that coats plastics when they enter fresh or marine waters. Researchers also call this sticky layer an <a href="https://doi.org/10.1126/sciadv.abd1211">eco-corona</a>. We then added the parasites to the test bottles and counted how many became stuck on the microplastics or remained freely floating in the seawater over a seven-day period.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pHLP5CZMnL4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Biofilms are vast communities of microbes that can form on almost any surface, including your teeth.</span></figcaption>
</figure>
<p>We found that significant numbers of parasites were clinging to the microplastic, and these numbers were increasing over time. So many parasites were binding to the sticky biofilms that, gram for gram, plastic had two to three times more parasites than did seawater.</p>
<p>Surprisingly, we found that microfibers (commonly from clothes and fishing nets) harbored a greater number of parasites than did microbeads (commonly found in cosmetics). This result is important, because microfibers are the most common type of microplastic found in <a href="https://doi.org/10.1016/j.marpolbul.2013.12.035">marine waters</a>, on <a href="https://doi.org/10.1016/j.scitotenv.2017.09.100">coastal beaches</a> and even in <a href="https://doi.org/10.1016/j.marpolbul.2018.12.039">seafood</a>.</p>
<h2>Plastics could change ocean disease transmission</h2>
<p>Unlike <a href="https://doi.org/10.1016/j.marenvres.2016.07.004">other pathogens</a> that are commonly found in seawater, the pathogens we focused on are derived from terrestrial animal and human hosts. Their presence in marine environments is entirely due to <a href="https://doi.org/10.1016/j.pt.2004.08.008">fecal waste</a> <a href="https://dx.doi.org/10.1016%2Fj.fawpar.2019.e00049">contamination</a> that ends up in the sea. Our study shows that microplastics could also serve as transport systems for these parasites.</p>
<p>These pathogens <a href="https://doi.org/10.1016/j.pt.2004.08.008">cannot replicate in the sea</a>. Hitching a ride on plastics into marine environments, however, could fundamentally alter how these pathogens move around in marine waters. We believe that microplastics that float along the surface could potentially <a href="https://www.nationalgeographic.com/science/article/microplastics-in-virtually-every-crevice-on-earth">travel long distances</a>, spreading pathogens far from their original sources on land and bringing them to regions they would not otherwise be able to reach.</p>
<p>On the other hand, plastics that sink will concentrate pathogens on the sea bottom, where filter-feeding animals like clams, mussels, oysters, abalone and other shellfish live. A sticky biofilm layer can camouflage synthetic plastics in seawater, and animals that typically eat dead organic material may <a href="https://doi.org/10.1126/sciadv.abd1211">unintentionally ingest them</a>. Future experiments will test whether live oysters placed in tanks with and without plastics end up ingesting more pathogens.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram illustrating how pathogens can associate with biofilms on microplastics and spread through the sea." src="https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=344&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=344&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=344&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=432&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=432&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459555/original/file-20220425-14-c1bmzs.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=432&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 biofilms that form on microplastics can help pathogens spread through the sea.</span>
<span class="attribution"><span class="source">Emma Zhang</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>A One Health problem</h2>
<p><a href="https://www.cdc.gov/onehealth/basics/index.html">One Health</a> is an approach to research, policy and veterinary and human medicine that emphasizes the close connection of animal, human and environmental health. While it may seem that plastic pollution affects only animals in the ocean, it can ultimately have consequences on human health.</p>
<p>Our project was conducted by a multidisciplinary team of experts, ranging from microplastics researchers and parasitologists to shellfish biologists and epidemiologists. This study highlights the importance of collaboration across human, animal and environmental disciplines to address a challenging problem affecting our shared marine environment.</p>
<p>Our hope is that better understanding how microplastics can move disease-causing pathogens in new ways will encourage others to think twice before reaching for that plastic straw or polyester T-shirt.</p>
<p>[<em>Get fascinating health and science news in your inbox.</em> <a href="https://memberservices.theconversation.com/newsletters/?nl=science&source=inline-science-fascinating">Sign up for The Conversation’s weekly science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/181824/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Shapiro receives funding from the Ocean Protection Council and California Sea Grant program
(Grant #19-0592).</span></em></p><p class="fine-print"><em><span>Emma Zhang received student funding from STAR (Students Training in Advanced Research) Program at UC Davis School fo Veterinary Medicine.</span></em></p>Normally land-bound pathogens that cause deadly diseases for both humans and animals can cling to microplastics and end up in your seafood.Karen Shapiro, Associate Professor of Pathology, Microbiology and Immunology, University of California, DavisEmma Zhang, Veterinary researcher, University of California, DavisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/980632018-07-11T11:15:22Z2018-07-11T11:15:22ZTriclosan, often maligned, may have a good side — treating cystic fibrosis infections<figure><img src="https://images.theconversation.com/files/226366/original/file-20180705-122274-zwsz42.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Antibiotic-resistant bacteria inside a biofilm.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/antibiotic-resistant-bacteria-inside-biofilm-3d-733165693?src=S-PIB9t8jY1oDGnWwDSB3w-1-0">Kateryna Kon/Shutterstock.com</a></span></figcaption></figure><p>Maybe you’ve had the experience of wading in a stream and struggling to keep your balance on the slick rocks, or forgetting to brush your teeth in the morning and feeling a slimy coating in your mouth. These are examples of <a href="http://www.biofilm.montana.edu/biofilm-basics/index.html">bacterial biofilms</a> that are found anywhere a surface is exposed to bacteria in a moist environment.</p>
<p>Besides leading to falls in streams or creating unhealthy teeth, <a href="https://theconversation.com/unlocking-the-secrets-of-bacterial-biofilms-to-use-against-them-59148">biofilms</a> can cause large problems when they infect people. Biofilms, multicellular communities of bacteria that can grow on a surface encased in their own self-produced matrix of slime, <a href="https://www.sciencedirect.com/science/article/pii/B9780128002629000019?via%3Dihub">can block immune cells</a> from engulfing and killing the bacteria or prevent antibodies from binding to their surface. </p>
<p>On top of this, bacteria in a biofilm <a href="http://www.jbc.org/content/291/24/12565.long">resist being killed</a> by antibiotics due to the sticky nature of the matrix and activation of inherent resistant mechanisms, such as slow-growing cells or the ability to pump antibiotics out of the cell. </p>
<p>Biofilms are one of the primary growth modes of bacteria, but all antibiotics currently used clinically were developed against <a href="http://www.mdpi.com/1420-3049/20/4/5286/htm">free-swimming planktonic bacteria</a>. This is why they do not work well against biofilms. </p>
<p><a href="https://msu.edu/%7Ewatersc3/">My laboratory</a> studies how and why bacteria make biofilms, and we develop new therapeutics to target them. Because <a href="https://www.nature.com/articles/s41579-018-0019-y">antibiotic resistance</a> is the most problematic aspect of biofilms during infections, we set out to identify novel molecules that could enhance antibiotic activity against these communities. </p>
<p>We discovered that an antimicrobial that has recently obtained a bad reputation for overuse in many household products could be the secret sauce to kill biofilms.</p>
<h2>The hunt for antibiotic superchargers</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=472&fit=crop&dpr=1 600w, https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=472&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=472&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=593&fit=crop&dpr=1 754w, https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=593&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/226772/original/file-20180709-122277-1xmz7kg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=593&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dr. Alessandra Agostinho Hunt measures biofilm formation of <em>Psuedomonas aerugionsa</em> by pipetting in the purple dye crystal violet to stain the microbial structure.</span>
<span class="attribution"><span class="source">Derrick Turner/Michigan State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>To find such compounds, we developed an <a href="https://www.medicinenet.com/script/main/art.asp?articlekey=8412">assay</a> to grow plates of 384 tiny <a href="http://aac.asm.org/content/62/6/e00146-18.long">biofilms</a> of the bacterium <a href="https://www.tandfonline.com/doi/abs/10.1517/14728220903454988?journalCode=iett20"><em>Pseudomonas aeruginosa</em></a>. We did this to screen for molecules that enhance killing by the antibiotic <a href="https://www.rxlist.com/consumer_tobramycin_nebcin/drugs-condition.htm">tobramycin</a>. We chose this bacterium and this antibiotic as our test subjects because they are commonly associated with <a href="https://www.cff.org/Life-With-CF/Daily-Life/Germs-and-Staying-Healthy/What-Are-Germs/Pseudomonas/">cystic fibrosis lung infections</a> and treatment.</p>
<p>People with cystic fibrosis (CF) are at particular risk from <a href="https://www.ncbi.nlm.nih.gov/pubmed/19374653">biofilm-based infections</a>. These infections often become chronic in the lungs of cystic fibrosis patients and are often never cleared, even with aggressive antibiotic therapy.</p>
<p>After we screened 6,080 small molecules in the presence of tobramycin, we found multiple compounds that showed the antibiotic enhancement activity we were searching for. Of particular interest was the antimicrobial <a href="https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm205999.htm">triclosan</a> because it has been widely used in household products like toothpaste, soaps and hand sanitizers for decades, indicating that it had potential to be safely used in CF patients. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/jat.1660">Triclosan</a> has also garnered a <a href="https://theconversation.com/why-you-should-dispense-with-antibacterial-soaps-65297">bad reputation</a> due to its overuse, and states like Minnesota have banned it from these products. The <a href="https://theconversation.com/why-you-should-dispense-with-antibacterial-soaps-65297">Food and Drug Administration banned</a> its use from hand soaps in September 2016. This ruling was not based on safety concerns, but rather because the companies that made these products did not demonstrate higher microbial killing when triclosan was added, compared to the base products alone.</p>
<p>Another fact that piqued our interest is that <em>P. aeruginosa</em> is resistant to triclosan. Indeed, treatment with either tobramycin or triclosan alone had very little activity against <em>P. aeruginosa</em> biofilms, but we found that the combination was 100 times more active, killing over 99 percent of the bacteria.</p>
<p>We further studied this combination and found that it worked against <em>P. aeruginosa</em> and other bacterial species that had been isolated from the lungs of CF patients. The combination also significantly enhanced the speed of killing so that at two hours of treatment, virtually all of the biofilm is eradicated. </p>
<p>Our efforts are now focused on pre-clinical development of the <a href="https://www.tobipodhaler.com/index.jsp?usertrack.filter_applied=true&NovaId=2935377102246013691">tobramycin-triclosan combination</a>. For CF, we envision patients will inhale these antimicrobials as a combination therapy, but it could also be used for other applications such as diabetic non-healing wounds. </p>
<p>Although questions about the safety of triclosan have emerged in the mainstream media, there are actually dozens of studies, including in humans, <a href="https://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_166.pdf">concluding that it is well tolerated</a>, summarized in this extensive EU report from 2009. My laboratory completely agrees that triclosan has been significantly overused, and it should be reserved to combat life-threatening infections.</p>
<p>The next steps for development are to initiate safety, efficacy and pharmacological studies. And thus far, our own studies indicate that <a href="http://aac.asm.org/content/early/2018/04/10/AAC.00146-18.full.pdf+html">triclosan is well tolerated</a> when directly administered to the lungs. We hope that in the near future we will have enough data to initiate clinical trials with the FDA to test the activity of this combination in people afflicted with biofilm-based infections.</p>
<p>We think our approach of enhancing biofilm activity with the addition of novel compounds will increase the usefulness of currently used antibiotics. Learning about how these compounds work will also shed light on how bacterial biofilms resist antibiotic therapy.</p><img src="https://counter.theconversation.com/content/98063/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Waters receives funding from the NIH, NSF, Michigan State University, and Hunt for a Cure Foundation to support this research.</span></em></p>Triclosan, an ingredient in soap and many household cleansers, has gained a bad reputation. A recent study looking for a way to boost an antibiotic, however, found that tricloscan did a great job.Chris Waters, Associate Professor of Microbiology, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/591482016-06-01T01:00:21Z2016-06-01T01:00:21ZUnlocking the secrets of bacterial biofilms – to use against them<figure><img src="https://images.theconversation.com/files/124356/original/image-20160527-894-iuv5a8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's bacterial biofilms that give the Grand Prismatic Spring its colorful hues.</span> <span class="attribution"><span class="source">Karin Sauer</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Standing on a walkway at Yellowstone National Park, I admired the hues of orange, blue and yellow in the sand of the Grand Prismatic Spring. A small sign nearby read “bacterial mats.” Visitors to Yellowstone may have noticed similar signs all over the park, but they’re often overlooked on the way to waterfalls, geysers, hot springs and more.</p>
<p>But these colorful structures at my feet were the reason I had come. Well, I needed a vacation – and what better place then Yellowstone? – but professional curiosity had a lot to do with the destination. I’m a microbiologist, and I had come to see the bacterial mats.</p>
<p>More commonly known as biofilms, these communities of tightly packed bacteria grow in close association with surfaces such as sand and soil. The term “biofilms” suggests a thin, two-dimensional substance, but these communities feature microscopic-scale tower-like structures crisscrossed with water channels, all of which is encased in a protective, self-produced slimy layer. The bacteria within communicate and demonstrate cooperative behavior reminiscent of primitive organs.</p>
<p>As visually stunning as I find these biofilms in nature, these bacterial communities can be detrimental to human health. Scientists like me are investigating how these bacterial biofilms form and behave so we can figure out new ways to manage and control them.</p>
<h2>Biofilms are all around us</h2>
<p>While made up of bacteria that are invisible to the naked eye, biofilms themselves can be much bigger, ranging from less than an inch to several hundred feet in size. Yellowstone is home to the most extensive and most colorful biofilms I’ve ever seen, but these bacterial communities are not unique to the park. Biofilms are found anywhere in nature, visible as <a href="http://genomealberta.ca/blogs/curiosity-about-stromatolites-and-biofilm.aspx">stromatolites</a>, pond scum and the slimy, slippery layer coating rocks and pebbles in streams.</p>
<p>And biofilms are not limited to the environment, either, since bacteria will stick to almost any surface in aqueous conditions and encase themselves with a slime matrix. Indeed, biofilms pose <a href="http://dx.doi.org/10.1080/87559129209540953">numerous problems to human-made materials</a> such as ship hulls, cooling towers, sewage treatment plants, oil refineries, food processing and beverage plants, and household plumbing. You’ve likely seen them yourself while cleaning or doing repairs in your kitchen or bathroom, as a thick and slimy buildup in your drains and pipes. Biofilms can be a real nuisance, <a href="http://www.slideshare.net/mfornalik/intro-to-biofilms-3522031">causing biofouling and corrosion</a>.</p>
<p>The <a href="http://dx.doi.org/10.1126/science.284.5418.1318">ubiquity of biofilms</a> in our surroundings is supported by findings that the majority of bacteria, up to 90 percent, prefer <a href="http://www.ncbi.nlm.nih.gov/pubmed/340020">living in surface-associated biofilm communities</a> rather than as free-floating, individual bacteria (what we call planktonic bacteria).</p>
<p>So why do bacteria <a href="http://dx.doi.org/10.1128/JB.00003-12">tend to form communities</a>? For one thing, there’s strength in numbers. By banding together within their slimy protection, biofilm bacteria can remain in favorable locations or hosts, better withstand nutrient deprivation, stress, dessication and predation. At the same time, they benefit from increased cooperation and exchange of genetic material.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/124520/original/image-20160530-7692-10riis.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">Scanning electron micrograph of part of a central venous catheter, removed from a patient, that was colonized by a biofilm of rod-shaped bacteria associated with fibrinlike material on the catheter’s surface.</span>
<span class="attribution"><a class="source" href="http://phil.cdc.gov/">Janice Haney Carr</a></span>
</figcaption>
</figure>
<h2>Biofilms can harm human health</h2>
<p>Biofilms have been linked to contamination of <a href="http://dx.doi.org/10.1089/10445490260099700">contact lenses leading to corneal ulcers</a>. They’re associated with <a href="http://dx.doi.org/10.1177/0022034510368644">dental plaque that leads to caries and periodontitis</a>. <a href="http://dx.doi.org/10.1126/science.284.5418.1318">They can infect</a> <a href="http://dx.doi.org/10.1007/978-3-319-09782-4">surgical sites</a>, the urinary tract, chronic and burn wounds and the lungs of cystic fibrosis patients. And they love to <a href="http://dx.doi.org/10.1016/B978-0-323-22805-3.00005-0">colonize medical devices</a> such as catheters, prosthetic joints and heart valves.</p>
<p>According to the National Institutes of Health, more than 65 percent of <a href="http://dx.doi.org/10.1111/2049-632X.12151">chronic inflammatory and infectious diseases</a> are due to biofilms. According to research, biofilm-related infections claim as many lives as heart attack or cancer. And they are costly, with treatment of biofilm-related infections <a href="http://dx.doi.org/10.1002/bit.21838">ranging into the billions</a> annually worldwide.</p>
<p>Why are we not better equipped to treat such bacterial infections? Research by my laboratory and others has demonstrated that when bacteria attach to a surface and grow as biofilms, they undergo a change, as evidenced by the genes they express and the proteins they produce. One of the consequences of this change is that biofilm bacteria become less susceptible to biocides, disinfectants and antibiotics. </p>
<p>Scientists think there are several reasons for this decrease in susceptibility. First, the slimy layer encasing biofilms can make it hard for disinfectants or antimicrobials to even physically reach the bacteria. Also, bacteria living in biofilms experience high stress levels while growing rather slowly, which can render most antibiotics ineffective since they only work on actively growing cells. My favorite theory is that living in a biofilm changes bacteria and their behavior; something about their mix of active genes and proteins just makes them more resilient. Whatever the contributing factors, bacteria growing in a biofilm can be <a href="http://dx.doi.org/10.1128/JB.00765-12">up to 1,000-fold more resistant to antibiotics</a> than the same bacteria grown planktonically.</p>
<p>This profound tolerance to antimicrobial agents – a hallmark of biofilms – is at the root of many persistent infections and renders biofilms extremely difficult to control in medical settings. <a href="http://www.ncbi.nlm.nih.gov/books/NBK84450/">Conventional therapies have proven inadequate</a> in the treatment of many if not most chronic biofilm infections, mainly because they have been geared toward bacteria growing planktonically and not as biofilms.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=264&fit=crop&dpr=1 600w, https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=264&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=264&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=332&fit=crop&dpr=1 754w, https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=332&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/124591/original/image-20160531-1943-1tkghh6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=332&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 formation of surface-associated biofilm communities (A) can be prevented or significantly reduced (B) by interfering with key factors required for their development. Bacterial cells are stained green.</span>
<span class="attribution"><span class="source">Karin Sauer</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>New lines of attack against biofilms</h2>
<p>Research suggests a promising new avenue for biofilm control: the manipulation of the biofilm lifestyle. Yes, for bacteria, being in a biofilm is a lifestyle choice.</p>
<p>The biofilm way of life is initiated when a few planktonic bacteria adhere to a surface. Once attached, these bacteria will divide and grow into more complex, three-dimensional structures – the biofilm. If resources become exhausted or the biofilm become too overcrowded, bacteria can escape it, as a means of survival and dissemination.</p>
<p>It’s the two extremes of their lifestyle, the beginning and the end, attachment and escape, that have become major foci of research endeavors looking for ways to defeat biofilms.</p>
<p>When it comes to controlling attachment, much research has focused on the <a href="http://dx.doi.org/10.1111/j.1574-695X.2011.00858.x">development of new surface materials</a> aimed at preventing the formation of biofilms on medical devices in the first place. The idea is to render devices’ surfaces nonsticky, repelling or otherwise toxic for those first pioneering bacteria. If they can’t latch on and get a toehold, no biofilm can eventually form. Surface coatings containing colloidal silver, antibiotics or micro-brushes can render medical devices inhospitable.</p>
<p>Likewise, the hunt is on for new chemical compounds that prevent attachment or induce escape strategies. Researchers are <a href="http://dx.doi.org/10.1128/JB.01214-08">starting to have some success</a>.</p>
<p><a href="http://bingweb.binghamton.edu/%7Eksauer/">My own research</a>, along with that of colleagues at Binghamton University and around the world, has led me down another path. I’ve been trying to understand how bacteria actually make these amazing biofilm structures. What proteins, polymers and factors do they need to coordinate their lifestyle? What have we learned that would let us manipulate this biofilm lifestyle?</p>
<p>It’s unlikely there will be only one effective treatment strategy to defeat biofilms. For one thing, many varieties of bacteria form biofilms, and they all use somewhat different strategies to enable this lifestyle. For instance, while bacteria may coordinate the formation of biofilms via chemical signals, the molecules used by bacteria such as <em>E. coli</em> or <em>S. aureus</em> to do so differ quite dramatically. Likewise with the species-specific sets of proteins required to coordinate the formation of each kind of biofilm. So as we target individual characteristics, some of our tactics work better on one group than another. </p>
<p>But biofilm bacteria also share some common features that we can take advantage of, including their need for communication and coordination. Building a biofilm, escaping from the biofilm or even living in a biofilm requires some sort of coordination among the millions of bacteria that make it up. They can do so by communicating with each other, using a chemical language or proteins. Jamming the bacterial language (although there are many) or interfering with their key factors required for coordination has proven to be a successful strategy to block or modify biofilm formation, at least in laboratory settings and some clinical pilot studies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/124590/original/image-20160531-1943-iim40a.png?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">Biofilms before (A) and after (B) exposure to ‘Escape from the biofilm!’ chemical signal. Note the biofilms in (B) are hollow, appearing like empty shells. Bacterial cells are stained in green.</span>
<span class="attribution"><span class="source">Karin Sauer</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Likewise, repurposing the bacterial language has shown promise. For instance, when we co-opt the bacterial language to signal “<a href="http://dx.doi.org/10.1128/JB.01214-08">escape from the biofilm!</a>” we can trick biofilm bacteria into giving up their protective lifestyle and converting to planktonic cells again. The added benefit is the planktonic cells are more susceptible to antibiotics.</p>
<p>Controlling biofilms in the future will likely require a combination of strategies, addressing both attachment and escape, with and without the use of antibiotics and communication blockers, and likely in a manner more or less tailored toward the different bacterial lifestyles.</p><img src="https://counter.theconversation.com/content/59148/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>My research is currently supported by grants from the National Institute of Health and F. Hoffmann-La Roche Ltd.
</span></em></p>The vast majority of the bacteria that surround us are not free-floating but prefer to band together in cooperative communities called biofilms. How do biofilms form and cooperate?Karin Sauer, Professor of Biological Sciences, Binghamton University, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.