Team:Toulouse/ethics

From 2014.igem.org

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<p class="texte">SubtiTree will live in sap tree, that is why we use one endophyte Bacillus subtilis strain. In order to contain our bacteria in this area during a short period of time, we modified some of its survival characteristics.   
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<p class="texte">SubtiTree will live in sap tree, thus we use one endophyte <I>Bacillus subtilis</I> strain. In order to contain our bacteria in this area during a short period of time, we modified some of its survival characteristics.   
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First, the control of synthetic bacterium location concerned us,that is why we border it inside the plane tree. Sap tree is known to contain a certain quantity of proline which could allow bacterial growth whereas the soil is composed by only trace of this amino acids. Thus we decide to delete the proline production pathway to make an auxotrophic bacterium for this amino acid.  
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First of all, the control of synthetic bacterium location concerned us,that is why we border it inside the plane tree. Sap tree is known to contain a certain quantity of proline which could allow bacterial growth whereas the soil is composed by only trace of this amino acid. Thus, we decided to delete the proline production pathway to make an auxotrophic bacterium for this amino acid.  
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<p class="texte">Secondly, SubtiTree is an annual bacterium to avoid any kind of mutations. It is known that endophyte bacteria must sporulate to survive to winter. Thus, we chose a B.subtilis strain without late genes of sporulation. So SubtiTree is a non-sporulation bacterium, which means that in stress conditions (cold temperature, food lack …) or outside the sap, the bacterium will not resist and die.</p>
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<p class="texte">Secondly, SubtiTree is conceived as an annual bacterium to avoid any kind of mutations. It is known that endophyte bacteria must sporulate to survive to winter. Thus, we chose a <I>B.subtilis</I> strain without late genes of sporulation. So SubtiTree is a non-sporing bacterium, which means that under stress conditions (cold temperature, food lack …) or outside the sap, the bacterium will not resist and die.</p>
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<p class="texte">These two characteristics of SubtiTree show that it’s an annual bacterium, which can only grow in sap tree. Combined they prevent any long term colonization of an ecological niche by SubtiTree against wild bacteria. These prevent any long term effect.</p>
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<p class="texte">These two characteristics of SubtiTree show that it is an annual bacterium, which can only grow in sap tree. By combinind them, they prevent any long term colonization of an ecological niche by SubtiTree against wild type bacteria. These prevent a long term effect.</p>
<p class="texte"><I><CENTER>Gene transfer</I></CENTER></p>
<p class="texte"><I><CENTER>Gene transfer</I></CENTER></p>
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<p class="texte"> We try to respond to bacterial spread problem, at the same time we wonder about horizontal gene transfer. The transmission of some genes from our synthetic bacterium to wild bacteria could be block with two modifications.   
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<p class="texte"> While we were trying to respond to bacterial spreading problem, at the same time we wondered about horizontal gene transfer. The transmission of genes from our synthetic bacterium to wild type bacteria could be blocked with two modifications.   
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First, as used in genetic engineering, plasmids are a tremendous way to transfer some genic information. In this way, it’s not the best way to restrict the collecting transgenic DNA. That is why we insert our genes in the bacterium chromosome.  
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First, as used in genetic engineering, plasmids are a tremendous way to transfer some genic information. In this way, it is not the best way to restrict the collecting transgenic DNA. That is why we inserted our genes in the bacterium chromosome.  
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<p class="texte">Secondly, some bacteria are able to accept chromosomal DNA, like Bacillus subtilis. Thus, the previous strategy is enough not efficient to prevent transfer. We could include the toxin/anti-toxin system. The toxin gene is near to our synthetic gene, contrary to the anti-toxin gene. So if there is a transfer of our synthetic gene, the toxin gene will be included in the transfer. Receiver bacteria will die by the production of the toxic protein. </p>
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<p class="texte">Secondly, some bacteria are able to accept chromosomal DNA, like <I>Bacillus subtilis</I>. Thus, the previous strategy is not efficient enough to prevent transfer. We could include the toxin/anti-toxin system. The toxin gene is near our synthetic gene, contrary to the anti-toxin gene. So if there is a transfer of our synthetic gene, the toxin gene will be included in the transfer. Receiver bacteria will die by the production of the toxic protein. </p>
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<p class="texte">Our synthetic genes are not the only problem in the design of SubtiTree. One of the side effects of our cloning method is the persistence of antibiotic resistance genes. This is incompatible with the introduction of SubtiTree in the environment. It is possible to delete this resistance in chromosome. To conclude, the spreading limitation as shown before makes the use of SubtiTree acceptable in the wild.  
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<p class="texte">Our synthetic genes are not the only problem in the design of SubtiTree. One of the side effects of our cloning method is the persistence of antibiotic resistance genes. This is incompatible with the introduction of SubtiTree in the environment. It is possible to delete this resistance in chromosome. To conclude, the spreading limitation shown previously makes the use of SubtiTree acceptable in the environment.  
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<p class="texte"><I><CENTER>Political and public adhesion</I></CENTER></p>
<p class="texte"><I><CENTER>Political and public adhesion</I></CENTER></p>
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<p class="texte">Thanks to the bolts we used in SubtiTree construction, its application interest civil services. Indeed some city halls and regional council support our local engagement. Beyond that, our project interests the highest level of the “Canal du Midi” administration: the national navigation authority and the ministry of agriculture fund this project. They are still interest in to continue this work after the iGEM competition context. </p>
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<p class="texte">Thanks to the bolts we used in SubtiTree construction, its application interest civil services. Indeed some city halls and regional councils supported our local engagement. Beyond that, our project interests the highest level of the “Canal du Midi” administration: the national navigation authority and the Ministry of agriculture funded this project. They are still interested in continuing this work after the iGEM competition. </p>
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<p class="texte">This project also received the attention of the public through several article in newspaper, television, radio and internet. First we have just a local coverage, but day after day there is some national media which come to us. This coverage media allows us to have contact with regular people and thanks to that they participate in the development of this project. This interaction with the public allows us to develop the safety matter of our project. The support they give to us is the result of the scientific popularization of our project.  </p>
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<p class="texte">This project also received the attention of the public through several articles in newspapers, television, radio and internet. First we had just a local coverage, but days after days there were some national media coming to us. This coverage media allowed us to have contact with regular people and thanks to that they participated in the development of this project. This interaction with the public allowed us to develop the safety matter of our project. The support they gave us is the result of the scientific popularization of our project.  </p>
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<p class="texte">We wonder about the feasibility of tree’s treatment. As we used endophytic bacteria, we can count on the natural growth of SubtiTree inside the sap. So we can inject few bacteria to be sure to have enough bacteria to protect the tree. Some researchers already inject bacillus subtilis strain in plants and observe an increase of bacteria concentration to a maximum of 105 bacteria/mL.  </p>
<p class="texte">We wonder about the feasibility of tree’s treatment. As we used endophytic bacteria, we can count on the natural growth of SubtiTree inside the sap. So we can inject few bacteria to be sure to have enough bacteria to protect the tree. Some researchers already inject bacillus subtilis strain in plants and observe an increase of bacteria concentration to a maximum of 105 bacteria/mL.  </p>
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<p class="texte">As we inject a poor quantity of bacteria, the injection remains cheaper than the injection of several litter of fungicide. Plus this injection prevents the cutting of trees, which is very expensive. Cutting one tree cost around 3 K€. The administration in charge of the protection of the “Canal du Midi” already plans to spend 220 million euros to cut and replant all trees along the Canal. Besides the important cost of cutting tree, it will destroy one of the symbols of south-west France. </p>
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<p class="texte">As we inject a poor quantity of bacteria, the injection remains cheaper than the injection of several litter of fungicide. Plus this injection prevents the cutting of trees, which is very expensive. Cutting one tree cost around 3 K€. The administration in charge of the protection of the “Canal du Midi” already plans to spend 220 million euros to cut and replant all trees along the Canal. Besides the important cost of cutting tree, it will destroy one of the symbols of south-west of France. </p>
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<p class="texte">We know that SubtiTree could be improve in many ways, but in the iGEM’s circumstances we could not have the time to go deeper. First, we can improve the fixation module. Using chitin as fixation anchor is simple but not enough specific to fix just one fungus type. That’s why we first think to fix SubtiTree to one protein included in the Ceratocystis platani’s membrane: CP. </p>
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<p class="texte">We know that SubtiTree could be improve in many ways, but in the iGEM’s circumstances we could not have the time to go deeper. First, we can improve the fixation module. Using chitin as fixation anchor is simple but not enough specific to fix just one fungus type. That’s why we first think to fix SubtiTree to one protein included in the <I>Ceratocystis platani</I>’s membrane: CP. </p>

Revision as of 12:07, 12 October 2014