Team:WHU-China/Project/Death

From 2012.igem.org

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<h2> Outline</h2>
<h2> Outline</h2>
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<p>
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We plan to place endonuclease and YhjH gene downstream the xylR induce to make bacteria die and lose their adhesion when exposed to xylose.
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We plan to place endonuclease and YhjH gene downstream the xylR repressed promoter to make bacteria die and lose their adhesion when exposed to xylose.
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<h2> Description </h2>
<h2> Description </h2>
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<img src="https://static.igem.org/mediawiki/2012/archive/0/02/20120914181638%21Death.jpg" width="410.67" height="264" hspace="2" vspace="1" border="2"  
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<img src="https://static.igem.org/mediawiki/2012/c/c3/Death.png" width="410.67" height="264" hspace="2" vspace="1" border="2"  
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In order to terminate the overreaction of fatty acid metabolism and cellulose synthesis, we design an elaborate device to  
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In order to terminate the overreaction of fatty acid metabolism and cellulose synthesis, we design an elaborate device. Firstly, we determined to use endonuclease YhjH responsible for c-di-GMP degradation to counteract the impact of AdrA and BglII(BBa_K112106), a protein that can kill the microbe without inducing cell lysis. Since AdrA but not YhjH contains this restriction site, our E.coslim will lose their adhesion more easily. To control the expression of endonuclease and YhjH, a regulator is
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avoid it. Firstly, we determine to use endonuclease([http://partsregistry.org/Part:BBa_K112106 BBa_K112106]), a molecular
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necessary. We selected xylose as the inducer because this monomer hardly exists in nature, so the GMOs will not be killed under natural condition. Also, it is healthy and hard to be absorbed by human beings so the concentration of xylose in the gut can keep high for a long time. We are planning to device another synthetic promoter repressed by XylR from <i>B.subtilis</i>. We hope that eating xylose will
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which can kill the microbe without inducing cell lysis. To control the expression of endonuclease, a regulator is
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subsequently derepress the expression of endonuclease and YhjH, ending up with the loss of adhesion and the death of our E.coslim.
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necessary. We select xylose as a controller because it is more healthy and hard to be absorbed by human. We find an ideal
 
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promoter BBa_K625002, which can be activated by the transcriptional regulator XylR. We hope that eating xylose will
 
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subsequently induce the expression of endonuclease, ending up with the death of our E.coslim.
 
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In addition, we use a pair of genes to strengthen the accuracy of controlling, namely YhjH. YhjH gene will counteract the
 
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impact of AdrA. YhjH protein can convert c-di-GMP in to GMP. Thus cells will lose their adhesion and become vulnerable to
 
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endonuclease.
 
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<h2> Forestalling HGT </h2>
<h2> Forestalling HGT </h2>
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is highly necessary.
is highly necessary.
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To prevent horizontal gene transfer, we designed a two plasmids system. In one plasmid, xlyR repressor encoding gene from  
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To prevent horizontal gene transfer, we designed a two-plasmids system. In one plasmid, xlyR repressor encoding gene from  
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Bacillus subtilis will be cloned. On the other plasmid, metabolic gene will be coupled with xylR repressed death system. In  
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<i>Bacillus subtilis</i> will be assembled with constitutively expressed promoter. On the other plasmid, metabolic gene will be coupled with xylR repressed death system. In  
our GMOs, since death system is suppressed by xylR in low xylose concentration, the bacteria will not die. However, when  
our GMOs, since death system is suppressed by xylR in low xylose concentration, the bacteria will not die. However, when  
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the HGT of those high efficient metabolic genes happened, the death system will not be suppressed, and the recipient will  
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the HGT of those high efficient metabolic genes happens, the death system will not be suppressed, and the recipient will  
be killed.
be killed.
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Latest revision as of 19:44, 26 September 2012

Death Device

Outline

We plan to place endonuclease and YhjH gene downstream the xylR repressed promoter to make bacteria die and lose their adhesion when exposed to xylose.

Description

In order to terminate the overreaction of fatty acid metabolism and cellulose synthesis, we design an elaborate device. Firstly, we determined to use endonuclease YhjH responsible for c-di-GMP degradation to counteract the impact of AdrA and BglII(BBa_K112106), a protein that can kill the microbe without inducing cell lysis. Since AdrA but not YhjH contains this restriction site, our E.coslim will lose their adhesion more easily. To control the expression of endonuclease and YhjH, a regulator is necessary. We selected xylose as the inducer because this monomer hardly exists in nature, so the GMOs will not be killed under natural condition. Also, it is healthy and hard to be absorbed by human beings so the concentration of xylose in the gut can keep high for a long time. We are planning to device another synthetic promoter repressed by XylR from B.subtilis. We hope that eating xylose will subsequently derepress the expression of endonuclease and YhjH, ending up with the loss of adhesion and the death of our E.coslim.



Forestalling HGT

In human gut, there are billions of microbes. Horizontal gene transfer of those high efficient metabolic genes between GMOs and normal intestine residents may get out of control and cause disastrous effects. Therefore, a mechanism to prevent HGT is highly necessary. To prevent horizontal gene transfer, we designed a two-plasmids system. In one plasmid, xlyR repressor encoding gene from Bacillus subtilis will be assembled with constitutively expressed promoter. On the other plasmid, metabolic gene will be coupled with xylR repressed death system. In our GMOs, since death system is suppressed by xylR in low xylose concentration, the bacteria will not die. However, when the HGT of those high efficient metabolic genes happens, the death system will not be suppressed, and the recipient will be killed.