tag:theconversation.com,2011:/fr/topics/nature-biotechnology-12886/articlesNature Biotechnology – The Conversation2016-11-13T07:00:33Ztag:theconversation.com,2011:article/682442016-11-13T07:00:33Z2016-11-13T07:00:33ZHow biotechnology could offer hope for snakebite victims<figure><img src="https://images.theconversation.com/files/144546/original/image-20161104-25329-m9kg8g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The black mamba is one of the most notorious venomous snakes in the world.</span> <span class="attribution"><a class="source" href="https://c2.staticflickr.com/6/5556/14707823092_fc246dc441_b.jpg">Flickr</a></span></figcaption></figure><p>Snakebite is a major public health burden for low-income countries in tropical parts of the world. There are around <a href="http://www.snakebiteinitiative.org/?page_id=577">5 million bites and 150,000 deaths</a> every year. And about <a href="https://www.msf.org.za/about-us/publications/briefing-documents/snakebite-how-public-health-emergency-slithered-under-radar">400,000 victims become permanently disabled</a> annually.</p>
<p>In Africa, the most notorious of snake species is the black mamba (<em>Dendroaspis polylepis</em>). It is feared for its <a href="http://www.sciencedirect.com/science/article/pii/S1874391915000561">potent rapid-acting venom</a> and its characteristic feature of typically striking more than once. The problem is that it always injects venom in its bite. So a bite from this species has an almost 100% fatality rate if left untreated. Other venomous African snake species that pose a danger to humans include other mambas, cobras, puff adders, boomslangs, and a range of vipers.</p>
<p>Treatment against snakebite venom is currently limited to antiserum derived from animals. There have been incremental innovations in the manufacture of antivenoms. But most are still produced using <a href="http://www.who.int/bloodproducts/snake_antivenoms/snakeantivenomguideline.pdf">methods developed 120 years ago</a>. Current antivenom production involves immunising animals, like horses or sheep, with venom milked from snakes and then isolating antibodies from the serum. The process is expensive and labour intensive.</p>
<p>A combination of these factors and a difficult market environment has some led commercial producers <a href="http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0001670">to withdraw</a>. As a result, current stocks of functional antivenom will <a href="http://www.nature.com/news/vipers-mambas-and-taipans-the-escalating-health-crisis-over-snakebites-1.20495">soon expire</a>. The situation is so bad that experts and NGOs active in the field refer to the lack of antivenom – particularly in sub-Saharan Africa – as <a href="http://www.nature.com/news/africa-braced-for-snakebite-crisis-1.18357">a neglected health crisis</a>.</p>
<p>But there is hope on the horizon. Innovations in biotechnology being used to produce pharmaceuticals for other treatments could also be applied to producing antivenoms. These would be made in laboratory conditions rather than extracted from animals.</p>
<p>We have been exploring various avenues to produce antivenoms based on mixtures of antibodies, rather than having them derive from animals. This is a scientifically and commercially sound opportunity that promises to bring the shortage of snakebite antivenoms in sub-Saharan Africa to an end, not immediately but certainly in the medium to longer term.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=613&fit=crop&dpr=1 600w, https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=613&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=613&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=771&fit=crop&dpr=1 754w, https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=771&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/144548/original/image-20161104-25322-wxr379.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=771&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Schematic representation of serum-based antivenom production.</span>
<span class="attribution"><span class="source">Andreas Hougaard Laustsen</span></span>
</figcaption>
</figure>
<h2>What biotechnology can deliver</h2>
<p>Innovations in biotechnology can make antivenoms more cost-effective and easier to produce. They can also be made more effective against snakebites. Alternative avenues, already established within biotechnology, could be pursued to create novel ones. These have the potential to improve treatment against snakebite and lower cost of production. Lower manufacturing costs would make it profitable for pharmaceutical companies to bring low cost antivenoms to the market. It could even provide a financial incentive for antivenom manufacturers to distribute antivenoms to rural parts of the tropics.</p>
<p>One established method that could be adapted is the use of DNA immunisation techniques. This would do away with laborious venom extractions. This technique would involve immunising horses <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0030184">with toxin-encoding DNA</a>, inducing immunisation (similar to the effect that venom itself provides). This technique has been investigated in various animal models and may enable venom-independent antivenom manufacture <a href="https://www.researchgate.net/publication/268810231_Developing_Snake_Antivenom_Sera_by_Genetic_Immunization_A_Review">in the future</a>. </p>
<p>But we are following a different avenue. We are pursuing the replacement of the active components (antibodies) in the animal-derived antivenom with <a href="https://www.researchgate.net/publication/308249085_Recombinant_Antivenoms">recombinant human versions</a> – antivenoms produced by cell cultivation in biotechnological production systems. This method, producing pharmaceutical products through cell cultivation <a href="http://www.diabetesforecast.org/2013/jul/making-insulin.html">in fermentation tanks</a>, has been developed and perfected over the last 30 years. It’s been used to produce a range of pharmaceutical products like blood factors and human hormones such as insulin. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=502&fit=crop&dpr=1 600w, https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=502&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=502&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=631&fit=crop&dpr=1 754w, https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=631&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/144549/original/image-20161104-25362-kwu41t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=631&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Schematic representation of two strategies for the manufacture of oligoclonal antibody mixtures by cell cultivation.</span>
<span class="attribution"><span class="source">Andreas Hougaard Laustsen</span></span>
</figcaption>
</figure>
<p>Future recombinant antivenoms could be based on mixtures of human antibodies. These antivenoms would be more compatible with the human immune system, limiting the incidence of adverse reactions. The concept has seen success in <a href="http://www.nature.com/nature/journal/vnfv/ncurrent/full/nature13777.html?utm_content=bufferb2c23&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer#affil-auth">ZMapp, a medication used to fight Ebola</a> and therapies involving oncology based <a href="http://www.symphogen.com/pipeline">antibody mixtures</a>.</p>
<h2>Costing</h2>
<p>A recombinant antivenom would also be more effective. This is because current antivenoms contain a large fraction of therapeutically irrelevant antibodies. These are generated by animals’ immune systems to fight a range of bacteria and viruses. A recombinant antivenom, based on a mixture of human antibodies, would be designed in a way that the antibodies would be specifically selected to target the most relevant toxins in snake venom. Therapeutically irrelevant antibodies not targeting snake toxins would be absent. </p>
<p>But, wouldn’t this be exorbitantly <a href="http://www.nature.com/news/vipers-mambas-and-taipans-the-escalating-health-crisis-over-snakebites-1.20495">expensive?</a> Not at all. Our estimates show that recombinant antivenoms would be a <a href="http://www.nature.com/nature/journal/v538/n7623/full/538041e.html">cost-effective solution</a> to the snakebite crisis. They could be used to treat an average snakebite case in Africa for $30-$150 per treatment compared with the current cost of well <a href="http://www.reuters.com/article/us-uk-snake-venom-idUSKBN0MT2F320150402">over $500</a>. </p>
<p>Recombinant antivenoms are still under development. They are unlikely to be on the market for about a decade. More focus and resources are needed to accelerate the discovery and testing of toxin-targeting antibodies of human origin. We hope our efforts will help catalyse this process and shorten the time in which more effective – and less expensive – antivenoms reach clinics.</p><img src="https://counter.theconversation.com/content/68244/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andreas Hougaard Laustsen receives funding from the Novo Nordisk Foundation (NNF16OC0019248).</span></em></p><p class="fine-print"><em><span>Mikael Engmark receives funding from The Novo Nordisk Foundation (NNF13OC0005613)</span></em></p>One way to tackle the snakebite antivenom crisis may be through biotechnological innovation to make antivenoms more cost-effective, easier to produce, and more efficacious against snakebites.Andreas Hougaard Laustsen, Postdoctoral Fellow at the Department of Biotechnology and Biomedicine, Technical University of DenmarkMikael Engmark, PhD Student Department of Bio and Health Informatics, Technical University of DenmarkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/604682016-06-23T14:47:29Z2016-06-23T14:47:29ZHow science can genetically strengthen endangered plants and agriculture<figure><img src="https://images.theconversation.com/files/127707/original/image-20160622-7175-1w2bhnq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Somatic embryogenesis is only used in selected agroforestry industries like sugarcane.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>As the human population swells – and in the face of a changing and unpredictable climate – the demand for natural resources increases. This leads to distressing rates of deforestation to prepare land for agriculture, medicinal and forestry products. Related to this is an alarming reduction in species worldwide.</p>
<p>This can only be ameliorated through urgent, intensive and sustainable agroforestry and conservation initiatives. This involves the conservation of natural forests as well as renewable plantation efforts. But to date only a scattering of such projects are in place worldwide. </p>
<p>Conservation and renewable plantation efforts are trailing behind the rate of resource exploitation and species disappearance. The problem is worsened by the vast number of endangered plant species. Once disturbed from their natural habitat, they can’t easily be reintroduced. This is because many of them do not readily produce seeds, or their seeds cannot be stored to ensure longevity of the species. The result is a decreasing gene pool. </p>
<p>This poses further risks, as vulnerable species become marginalised. They are only suitable to shrinking ranges and more susceptible to disease. To intensify conservation while enhancing agroforestry, smarter plant breeding practices are required.</p>
<p>Traditional breeding has allowed for the identification, selection and propagation of plants with a superior genetic makeup, or genotype, from a given plant population. But traditional methods often fail to isolate the required superior characteristics of a species. They can also take more than five or six breeding cycles before a valuable trait is established and maintained in a plant population. The process can take decades for perennial plants, like trees. </p>
<p>Plant biotechnology is increasingly being used to complement traditional screening and <a href="https://agricultureandfoodsecurity.biomedcentral.com/articles/10.1186/2048-7010-1-7">breeding practices</a>. Plants can be grown in test tubes under controlled laboratory conditions. Advances in biochemistry and genetics have also ushered in an understanding of the factors that influence plant growth. </p>
<p>Together these developments have created the opportunity to precisely identify and mass propagate superior plant varieties within a fraction of the time of traditional methods. On top of this, if required, the precise altering of the genetic makeup of plants is now also possible. This enables plant genomes to be radically enhanced so that superior genotypes can be created, maintained and propagated. </p>
<h2>Preserving valuable genes</h2>
<p>Maintaining superior genetics for valuable traits is fundamental in agroforestry. But to maintain superior genetics, seed production is rarely an option. In producing a seed, the sexual cross between genetically different male and female parent plants results in the dilution of valuable genes. This often leads to offspring with unpredictable genetics. </p>
<p>For the agroforestry industry to succeed, genotypes with predictably fast growth rates, high yields, and disease and drought resistance are needed. This will ensure land-use efficiency is maximised, which in turn will decrease ecological disturbance and protect indigenous plant species and sensitive natural forests. </p>
<p>One method that holds promise for preserving valuable genes is somatic embryogenesis. This is the ability to produce viable embryos from virtually any plant organ, while avoiding sexual crossing. Such embryos, when encased in alginate gel, constitute a synthetic seed. They retain all the valuable properties of the cloned parent plant. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/127715/original/image-20160622-7175-1ufxsyv.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">Somatic embryogenesis is the ability to produce viable embryos from virtually any plant organ, while avoiding sexual crossing.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Creating synthetic seeds</h2>
<p>Somatic embryos may form naturally in certain plants, but can potentially be induced in any plant species and from any plant organ outside its normal biological context. This is done by altering the balance of plant hormones – the language signal in plants that controls all developmental processes. </p>
<p>Our <a href="https://www.researchgate.net/publication/294106816_Using_synergistic_exogenous_phytohormones_to_enhance_somatic_embryogenesis_from_leaf_explants_of_a_Eucalyptus_grandis_clone">research</a> investigated the potential of inducing somatic embryos from leaves of the commercially important Eucalyptus tree. These are an important source of global timber products. Intensive efforts are under way to screen and select preferred genotypes to support environmental sustainability. </p>
<p>Somatic embryos mimic seeds without the lengthy breeding cycle. The germinated products are essentially clones of the parent plant from which the embryos were induced. So somatic embryogenesis allows for superior genotypes to be preserved. It also allows for the propagation of plant species that were previously excluded from standard propagation practices like traditional plant breeding or plant tissue culture. </p>
<p>There are other benefits too. The easily transported embryos constitute known genetics and growth properties. They could also potentially be cryopreserved, that is frozen to ultra-low temperatures indefinitely in liquid nitrogen. Importantly, because of the conditions under which they are induced, they are disease-free.</p>
<p>Despite its many uses somatic embryogenesis is only being used in selected agroforestry industries like sugarcane, certain conifer and forestry plantations and in a <a href="http://www.academia.edu/1615682/Somatic_embryogenesis_for_crop_improvement">few ornamental plants</a>. But its potential as a medium for genetic enhancement cannot be ignored, especially given recent advances in gene editing.</p>
<h2>Gene editing</h2>
<p>With the drive to sequence whole genomes of commercially important, rare or valuable plant species, scientists are presented with an opportunity to identify, understand the functions of and edit specific gene sequences to enhance plant properties. </p>
<p>To date, one hurdle to the success of the process has been the choice of organ when genetically editing plants. </p>
<p>This is why somatic embryos could be very useful for gene editing. As embryos they contain both root and shoot meristems – the precursors to a complete plant. If genes are edited at this embryonic stage, then as the embryo divides to form the complete plant all cells of the entire plant will carry the edited genome. </p>
<p>The advent of highly accurate gene editing methods has provided scientists with the opportunity to improve forestry, agricultural and threatened plant species. This can be done in a precise, targeted and reproducible manner. One such example is the <a href="https://www.neb.com/tools-and-resources/feature-articles/crispr-cas9-and-targeted-genome-editing-a-new-era-in-molecular-biology">Crispr/Cas9 system</a>. This is a highly specific gene editing method that can be used to precisely replace whole gene sequences.</p>
<p>The potential exists to genetically insert tolerance to pests, disease, drought, floods and other pressures of a changing climate. Such precise gene editing will greatly benefit from readily available, disease-free embryos. In the near future, gene editing of synthetic seeds will allow extensive improvement of agricultural and forestry crops.</p>
<h2>Planning for the future</h2>
<p>The only historical limitation of somatic embryogenesis lay in the possibility of unplanned mutations arising from the embryo induction process. But advanced molecular screening techniques have mitigated this. </p>
<p>In time, we should expect to see greater use of enhanced, tolerant plant genotypes through specific gene editing of somatic embryos and synthetic seeds. What remains to be done is fervent research into the underlying mechanisms of somatic embryogenesis, their efficient conversion into synthetic seeds and successful cryopreservation. This should be done using a greater number of plant species for more efficient, productive, tolerant and sustainable agroforestry plantations, and in conservation programmes.</p><img src="https://counter.theconversation.com/content/60468/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Muhammad Nakhooda receives funding from National Research Foundation and Cape Peninsula University of Technology Research Fund. </span></em></p>Smarter plant breeding practices are crucial in a world where climate change, deforestation and species reduction are an increasing problem.Muhammad Nakhooda, Senior Lecturer in Biotechnology, Cape Peninsula University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/329152014-10-14T13:19:42Z2014-10-14T13:19:42ZDesigner viruses could be the new antibiotics<figure><img src="https://images.theconversation.com/files/61666/original/xnkvp9kk-1413275940.jpg?ixlib=rb-1.1.0&rect=0%2C52%2C600%2C406&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bacteria under attack by a flock of bacteriophages.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Phage.jpg">Graham Beards/Wikimedia Commons</a></span></figcaption></figure><p>Bacterial infections remain a major threat to human and animal health. Worse still, the catalogue of useful antibiotics is shrinking as pathogens build up resistance to these drugs. There are few promising new drugs in <a href="https://theconversation.com/new-antibiotics-whats-in-the-pipeline-10724">the pipeline</a>, but they may not prove to be enough. Multi-resistant organisms – also called “superbugs” – are on the rise and many predict a <a href="https://theconversation.com/a-peek-at-a-world-with-useless-antibiotics-and-superbugs-10984">gloomy future</a> if nothing is done to fight back.</p>
<p>The answer, some believe, may lie in using engineered bacteriophages – a <a href="https://theconversation.com/bacteria-eating-viruses-return-this-time-to-fight-superbugs-19301">type of viruses that infects bacteria</a>. Two recent studies, both published in the journal Nature Biotechnology, show a promising alternative to small-molecule drugs that are the mainstay of antibiotics today. </p>
<h2>From basic to synthetic biology</h2>
<p>Every living organism has evolved simple mechanisms to protect itself from harmful pathogens. This innate immune system can be a passive barrier, blocking anything above a certain size, or an active response that recognises foreign molecules – such as proteins and DNA – then kills them.</p>
<p>In bacteria, an important component of the immune system is composed of a family of proteins, which is tased specifically with breaking down foreign DNA. Each bug produces a set of these proteins that chew the genetic material of viruses and other micro-organism into pieces while leaving its own genome intact.</p>
<p>In vertebrates, a more advanced mechanism – called the adaptive immune system – creates a molecular memory of previous attacks and prepares the organism for the next wave of infection. This is the principle on which vaccines are built. Upon introduction of harmless pathogen fragments, the adaptive immunity will train specialist killer cells that later allow a faster and more specific response upon contact with the virulent agent.</p>
<h2>Crisp news</h2>
<p>Until recently, people thought bacteria were too simple to possess any sort of adaptive immunity. But in 2007 a <a href="http://www.sciencemag.org/content/315/5819/1709.abstract">group of scientists</a> from the dairy industry showed that bacteria commonly used for the production of cheese and yogurts could be “vaccinated” by exposure to a virus. Two years earlier, others had noticed similarities between repetitive sections in bacterial genomes and the DNA of viruses. These repetitive sequences – called CRISPR for “clustered regularly interspaced short palindromic repeats” – had been known for 20 years but no one could ever explain their function.</p>
<p>With both these observations it quickly became clear that bacteria were introducing viral DNA fragments into their own genome to protect themselves from later attacks. But it took another five years to get the whole picture. </p>
<p>In 2012, a <a href="http://www.sciencemag.org/content/337/6096/816.abstract">German team</a> identified all the pieces and showed how exactly bacteria transcribe viral DNA into a short RNA – usually the messenger molecule – which guides the DNA-cutting protein called Cas9 and tells it where to chop off viral DNA.</p>
<p>This could have been just one more interesting scientific observation, but in an era of synthetic biology, natural functions can quickly become designers tools. Within two years, many laboratories demonstrated that, by tailoring the short RNA guide, any gene could be cut out from a chromosome using the CRISPR-Cas9 system. </p>
<p>Since that breakthrough, hundreds of scientists have used it to manipulate the genome of bacteria, yeast, worms, crops, fruit flies, zebrafish, mice, rats, or even human cells. Although there are limitations, a procedure that used to take months using previous technologies – such as breeding or genome editing – can now be done in a few weeks.</p>
<h2>Bacterial immunity, rewired</h2>
<p>Now two teams of scientists, one led by <a href="http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.3011.html">Timothy Lu</a> of the Massachusetts Institute of Technology and the other by <a href="http://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.3043.html">Luciano Marriffini</a> of Rockefeller University, each used the CRISPR-Cas9 system to generate their own version of a prototype technology that turns a bacteria’s defence mechanism into a self-destructing weapon. The main idea behind their work was to use genetic engineering to rewire the bacteria’s immunity to produce “boomerang” antibiotic targets only bugs carrying specific genes.</p>
<p>To do this, their teams built an artificial CRISPR-Cas9 system – that could cut out specific genes – by assembling pieces in the lab before reintroducing it back into bacteria using viruses. Once injected into the bug, the guide RNA recruits the Cas9 protein to target genes that endow the bug antibiotic resistance or other harmful properties by embedding viral DNA. After those genes are removed, the superbug either dies or turns into an harmless one. </p>
<p>Although the method still needs improving to become useful for treatment, its ability to specifically kill pathogens has significant potential because it can limit their spread to other bacteria.</p>
<p>Fighting antibiotic resistance would not be the only application for these engineered viruses. Current small-molecule antibiotics also end up killing other healthy bacteria in our body. The new method would the harmless bugs intact, and thus minimise side-effects of antibiotics use.</p>
<p>In the past few years, the role of friendly <a href="https://theconversation.com/uk/topics/gut-bacteria">microbes living in the human gut</a> has become clearer. Imbalance in the diversity of species and their relative abundance may influence the development of certain conditions – including depression, diabetes and obesity. In this context, engineered viruses that would restore or shape the microbiota (or flora) could greatly improve health.</p><img src="https://counter.theconversation.com/content/32915/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luc Henry 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>Bacterial infections remain a major threat to human and animal health. Worse still, the catalogue of useful antibiotics is shrinking as pathogens build up resistance to these drugs. There are few promising…Luc Henry, Postdoctoral Fellow, EPFL – École Polytechnique Fédérale de Lausanne – Swiss Federal Institute of Technology in LausanneLicensed as Creative Commons – attribution, no derivatives.