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| {{:Team:Imperial_College_London/Templates/Header}} | | {{:Team:Imperial_College_London/Templates/Header}} |
| + | {{:Team:Imperial_College_London/style1}} |
| + | |
| <html> | | <html> |
- | <head> | + | <body> |
- | <script type="text/javascript"> | + | <h1>Overview</h1> |
- | $(document).ready(function(){
| + | |
- | var title = new Array();
| + | |
- | title[0] = "Desertification";
| + | |
- | title[1] = "Sub-saharan Africa";
| + | |
- | title[2] = "North American Plains";
| + | |
- | title[3] = "China and Central Asia";
| + | |
- | title[4] = "Indian Himalayas";
| + | |
- | var text = new Array();
| + | |
- | text[0] = "Mouse over the map to read about the impact of desertification in different areas.";
| + | |
- | text[1] = "Africa is the region most affected by desertification. Two thirds of the continent is covered by dryland which is used extensively for agricultural production. Over-cultivation has led to large scale degradation, exacerbated by frequent drought, leading to extreme food scarcity for some 650 million people who are dependent on the affected land. If the degradation trend continues, it is estimated that two thirds of Africa’s arable may be lost by 2025 (FAO 2009). In an effort to combat desertification, 11 countries along the southern border of the Sahara are involved in the Great Green Wall project. With the help of international aid, the objective is to cover 8,000 km of dryland with vegetation as a protective barrier from erosive forces. However the operation is extremely time consuming and will take a long time before it is established.";
| + | |
- | text[2] = "Historically, North America has experienced one of the most extreme effects of desertification during the 1930’s. The famous dust bowls of the Great Plains were brought on by over-cultivation of land and severe drought, causing degraded soil to be swept up by strong winds. Today about three quarters of North America’s drylands are affected by desertification. Counter-measures include synthetic materials to protect dryland, trenches to collect water, and windbreak structures. The use of beneficial soil microbes to improve growth of cacti has also been explored in an effort to re-vegetate deserts.";
| + | |
- | text[3] = "China is one of the largest dryland areas in the world, nearly a quarter of which is at risk of desertification. The problem has been fed by large-scale industrialisation with the over-use of land and water resources, as well as prolonged drought. Since 1978 the Great Green Wall project has been underway in the Kubuqi desert to protect cities from wind erosion carrying dust. The trees (Xinjiang poplars and willow species) are planted as saplings protected with wooden frames so they can take root before being blown away. These plants form fibrous roots that help hold down the sand. Although this project has slowed the desertification process in China, it remains an imminent problem.";
| + | |
- | text[4] = "Communities living in the Himalayas are heavily dependent on the forest as a resource for fuel wood and for their livestock. Increasing deforestation is leading to soil erosion and interference with water courses which is likely to have a major affect on inhabitants of the Ganges Plain who rely on the forest to slow flash floods. Small scale charities such as the Berkely Reafforestation Trust are working with local organisations to re-establish indigenous tree populations. So far they have funded the locally initiated reforestation of about 1600 hectares of degraded land and provided training programs to promote sustainability.";
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- | $("#maptitle").empty();
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- | $("#maptext").empty();
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- | $("#maptitle").append(title[3]);
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- | $("#maptext").append(text[3]);
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- | $("#maptitle").empty();
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- | $("#maptitle").append(title[0]);
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| + | |
- | </script> | + | |
| | | |
- | <style type="text/css"> | + | <p>Our team has decided to go down a novel route in tackling the human practices issues surrounding not only our project but also iGEM in general. Instead of sticking to the established routes of either proposing complete containment or relying on "kill switches" to prevent spread of GM bacteria, we have decided to engineer a containment switch that will not kill our AuxIn bacteria but all other microorganisms that take up the auxin-producing plasmid. In addition, we have consulted many experts and will conduct experiments that demonstrate the safety our device. The true scope of many iGEM projects can only be fulfilled if release is possible and we will be attempting to take a first step towards making this possible for our project.</p> |
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- | left:20px;
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- | z-index:0;}
| + | |
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| + | |
- | width:600px;
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- | height:460px;
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- | position:relative;
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- | top:0px;
| + | |
- | z-index:1;}
| + | |
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| + | |
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- | top:20px;
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- | font-weight:bold;
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- | background-color:#633e29;
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- | z-index:0;}
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| + | <p>Historically, iGEM teams have tried to control GM release via two mechanisms: complete containment and "suicide" mechanisms in which the bacteria kill themselves in the absence or presence of specific stimuli. However, when considering the eventual use of many projects – be it bioremediation (e.g. Peking 2010’s project), crop-enhancing projects (e.g. Bristol’s 2010 project) or other applications – full use of synthetic biology organisms will only be achieved by release and full containment is often not a realistic option. In addition, kill switches may be effective to an extent but they are easily selected against by evolution as they present a strong selective disadvantage. Stress defence mechanisms such as the SOS response in E coli add to this effect. In addition, transgenes can be transferred to other bacteria in the environment using naturally occurring mechanisms such as conjugation of plasmids. Finally, while it may be argued that engineered lab strains will quickly be outcompeted, bacteria with GM markers have been shown to become established in field trials (published in several papers, summary can be found on the <a href="http://ec.europa.eu/research/quality-of-life/gmo/02-plantgrowth/02-03-project.html">EU website</a>). In some cases, endurance of the bacteria in specific environments may even be desirable. |
- | width:100px;
| + | <a href="https://2011.igem.org/Team:Imperial_College_London/Protocols_General"><img src="https://static.igem.org/mediawiki/2011/5/58/ICL_ProtocolIconDark.png" width="32px" /></a> |
- | height:40px;
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- | position:absolute;
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| + | |
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| + | |
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- | | + | |
- | </style>
| + | |
- | </head> | + | |
- | | + | |
- | <body>
| + | |
- | <h1>What is Desertification</h1>
| + | |
- | <p>Desertification is the degradation of drylands which include arid, semi-arid and sub-humid areas. Drylands make up roughly 40 percent of the Earth’s land and are home to some two billion people, most of which live in developing countries. Dryland soil sustains a fragile ecosystem adapted to infrequent precipitation and dramatic temperature changes. Over-exploitation of dryland for cultivation and feedstock purposes renders the soil unproductive, forcing migration of communities in search of fertile land, leaving the unproductive land bare and vulnerable to erosive forces. A lack of food supply in many developing countries forces constant cultivation of land for short-term gain as well as deforestation to provide arable land.</p>
| + | |
| | | |
- | <h1>Case Studies</h1>
| |
- | <div id="mapmain">
| |
- | <img id="mappic" src="https://static.igem.org/mediawiki/2011/6/6f/ICL_DesertificationMap.jpg
| |
- | " />
| |
- | <div id="box1">
| |
- | </div>
| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
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| |
| | | |
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| + | <p>In light of these issues, we have decided to engineer Gene Guard, a containment switch that will lead to the lysis of natural soil bacteria that take up plasmid DNA from our engineered bacteria. We have consulted experts and the literature about the implications of our project and used this information to design an effective containment switch. However, we also tried to address all possible problems and complications arising from the impossibility of absolute control. Accordingly, we used the information we gathered to influence our release strategy and design.</p> |
- | </div>
| + | |
- | <div id="dot_box4">
| + | |
- | </div>
| + | |
- | <div id="empty4">
| + | |
- | </div>
| + | |
| | | |
- | <div id="mapbox">
| + | <p>However, we also acknowledge that this containment switch is never going to be completely effective. Accordingly, we have consulted ecologists and other experts on auxin, plants and soil to ensure that our device is as safe as possible and we can justify release. We researched other organisms such as soil microbes and earthworms that may be affected by the AuxIn bacteria and, with the help of the experts we consulted, devised experiments to test the safety and impact of many aspects of our project. </p> |
- | <div id="maptitle">Desertification
| + | |
- | </div>
| + | |
- | <div id="maptext">Mouse over the map to read about the impact of desertification in different areas.
| + | |
- | </div>
| + | |
- | </div>
| + | |
- | </div>
| + | |
| | | |
| </body> | | </body> |
| </html> | | </html> |
Our team has decided to go down a novel route in tackling the human practices issues surrounding not only our project but also iGEM in general. Instead of sticking to the established routes of either proposing complete containment or relying on "kill switches" to prevent spread of GM bacteria, we have decided to engineer a containment switch that will not kill our AuxIn bacteria but all other microorganisms that take up the auxin-producing plasmid. In addition, we have consulted many experts and will conduct experiments that demonstrate the safety our device. The true scope of many iGEM projects can only be fulfilled if release is possible and we will be attempting to take a first step towards making this possible for our project.
Historically, iGEM teams have tried to control GM release via two mechanisms: complete containment and "suicide" mechanisms in which the bacteria kill themselves in the absence or presence of specific stimuli. However, when considering the eventual use of many projects – be it bioremediation (e.g. Peking 2010’s project), crop-enhancing projects (e.g. Bristol’s 2010 project) or other applications – full use of synthetic biology organisms will only be achieved by release and full containment is often not a realistic option. In addition, kill switches may be effective to an extent but they are easily selected against by evolution as they present a strong selective disadvantage. Stress defence mechanisms such as the SOS response in E coli add to this effect. In addition, transgenes can be transferred to other bacteria in the environment using naturally occurring mechanisms such as conjugation of plasmids. Finally, while it may be argued that engineered lab strains will quickly be outcompeted, bacteria with GM markers have been shown to become established in field trials (published in several papers, summary can be found on the EU website). In some cases, endurance of the bacteria in specific environments may even be desirable.
In light of these issues, we have decided to engineer Gene Guard, a containment switch that will lead to the lysis of natural soil bacteria that take up plasmid DNA from our engineered bacteria. We have consulted experts and the literature about the implications of our project and used this information to design an effective containment switch. However, we also tried to address all possible problems and complications arising from the impossibility of absolute control. Accordingly, we used the information we gathered to influence our release strategy and design.
However, we also acknowledge that this containment switch is never going to be completely effective. Accordingly, we have consulted ecologists and other experts on auxin, plants and soil to ensure that our device is as safe as possible and we can justify release. We researched other organisms such as soil microbes and earthworms that may be affected by the AuxIn bacteria and, with the help of the experts we consulted, devised experiments to test the safety and impact of many aspects of our project.