Difference between revisions of "Team:Imperial College/Composite Part"

 
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<center><specialh3 style="font-size:40px;">Composite Parts</specialh3></center>
 
<center><specialh3 style="font-size:40px;">Composite Parts</specialh3></center>
<p><br><br><br>In this section we aim to present all the composite parts that we have built and used thorough our project. In addition we  introduce our best composite part: the pBAD-Gp2 construct, which provides a novel non-lethal way of inhibiting the growth of bacteria.</p>
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<div class="col-lg-12  text-justify"><p class="indent"><br><br><br>In this section, we aim to present all the composite parts that we have built and used thorough our project. In addition we  introduce our best composite part: the pBAD-Gp2 construct, which provides a novel non-lethal way of inhibiting the growth of bacteria.</p></div>
 
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<specialh3> Best Composite Part - pBAD-Gp2 </specialh3>
 
<specialh3> Best Composite Part - pBAD-Gp2 </specialh3>
  
<p><br>This year our best composite part is the pBAD-Gp2 construct. It provides a new way to repress growth in bacteria without killing the host cell. We have demonstrated that the cell is able to recover its initial growth rate once Gp2 is not expressed and can recover back to a normal growth rate. We are excited to provide this new growth regulator for the synthetic biology community and for the future iGEM teams.
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<div class="col-lg-12  text-justify"><p class="indent"><br>This year our best composite part is the pBAD-Gp2 construct, a new tool for repressing growth in bacteria without killing the host cell. We have demonstrated that the population is able to recover its initial growth rate once Gp2 is no longer expressed. We are excited to provide this new growth regulator for the synthetic biology community and for future iGEM teams.<br><br><br></div>
 
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<specialh4>Key Advantages</specialh4>
 
  
<p>→The protein is very small, and can inhibit growth within a half-hour timeframe. <br>
 
→The repression is robust and reversible.<br>
 
→The system does not require any toxins or supplements in the media.<br>
 
→Usage of the gene avoids the problem of antimicrobial resistance. <br><br>
 
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<img src="https://static.igem.org/mediawiki/2016/1/19/T--Imperial_College--composite_part.png" />
 
<p><b>Figure 1:</b> Schematic of the pBAD-Gp2 construct </p>
 
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<p><br><br>For our best composite part, we have selected the pBAD-Gp2 part. It was created by cloning a synthesised sequence block that contained Gp2, an RBS and the biobrick prefix and suffix, into an pBAD construct created by the 2014 Imperial iGEM team. <br><br><br>
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<br><br><specialh4>How does the pBAD-Gp2 construct work?</specialh4>
  
The construct effectively and rapidly downregulates the growth of E. coli in response to arabinose, and does so in a reversible manner. We believe it is a good alternative to existing growth control methods, especially for controlling co-culture, for several reasons<br><br>
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<div class="col-lg-12  text-justify"><p class="indent"><br>In the presence of arabinose (the promoter was active from 100 μM L-arabinose), the araC transcriptional regulator activates the pBAD promoter, resulting in the production of Gp2, a protein from T7 phage. Gp2 binds reversibly to the bacterial RNA polymerase, preventing protein production, and preventing the cell from dividing (Bae, B. et al, 2013). <br><br></div>
  
→Controlling cells in this way doesn’t require the usage of supplemented or minimal media, as in the case of antibiotics and auxotrophy.<br>
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→The gene is already naturally in the environment within the E.coli virus T7 phage, so there aren’t major biocontainment issues or the problems associated with antimicrobial resistance.<br>
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→It is specific to E. coli, and so, while possibly toxic to other prokaryotic bacteria, will not have any effect on eukaryotes. <br>
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→Gp2 is particularly good for regulating population size in co-cultures, as it only affects the size of one population.<br><br>  
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<img src="https://static.igem.org/mediawiki/2016/4/4c/T--Imperial_College--Gp2.png" height="400"/>
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            <img src="https://static.igem.org/mediawiki/2016/3/37/T--Imperial_College--GP2.png" height="250"/>
<p><b>Figure 2:</b> Growth inhibition of Top10 cells by induction of Gp2 by arabinose <br><br> </p>
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<p style="text-justify"><b>Figure 1. The pBAD-Gp2 construct.<br><br></p>
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<div class="col-lg-12  text-justify"><p class="indent"><br><br>The part was created by cloning a synthesised sequence block that contained Gp2, an RBS and the biobrick prefix and suffix, into an pBAD construct created by the 2014 Imperial iGEM team. <br><br><br>
<img src="https://static.igem.org/mediawiki/2016/d/de/T--Imperial_College--Gp2_repression_%281%29.png" height="400" />
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<p><b>Figure 3:</b> Recovery of growth by Top10 cells after induced araBAD operon is switched off by glucose-mediated catabolite repression.</p>
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The construct effectively downregulates the growth of E. coli in response to arabinose, and does so in a reversible manner. We believe it is a good alternative to existing growth control methods, especially for controlling co-culture, for several reasons. You can read more about our characterisation data on our results page. <br><br></div>
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<br><br><specialh4>Key advantages</specialh4><br>
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<li>Controlling cells in this way doesn’t require the usage of supplemented or minimal media, as in the case of antibiotics and auxotrophy.<br></li>
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<li>The system can easily be induced by L-arabinose, and switched off by D-glucose, both of which are non-toxic.<br></li>
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<li>Gp2 is particularly good for regulating population size in co-cultures, as it only affects the size of one population.<br><br></li>
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<specialh3>Reference</specialh3>
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<p>
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Bae, B., Davis, E., Brown, D., Campbell, E.A., Wigneshweraraj, S. and Darst, S.A., 2013. Phage T7 Gp2 inhibition of Escherichia coli RNA polymerase involves misappropriation of σ70 domain 1.1. Proceedings of the National Academy of Sciences, 110(49), pp.19772-19777.</p>
 
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<section id="Parts">
 
<section id="Parts">

Latest revision as of 03:31, 20 October 2016








Composite Parts




In this section, we aim to present all the composite parts that we have built and used thorough our project. In addition we introduce our best composite part: the pBAD-Gp2 construct, which provides a novel non-lethal way of inhibiting the growth of bacteria.

Best Composite Part - pBAD-Gp2


This year our best composite part is the pBAD-Gp2 construct, a new tool for repressing growth in bacteria without killing the host cell. We have demonstrated that the population is able to recover its initial growth rate once Gp2 is no longer expressed. We are excited to provide this new growth regulator for the synthetic biology community and for future iGEM teams.




How does the pBAD-Gp2 construct work?


In the presence of arabinose (the promoter was active from 100 μM L-arabinose), the araC transcriptional regulator activates the pBAD promoter, resulting in the production of Gp2, a protein from T7 phage. Gp2 binds reversibly to the bacterial RNA polymerase, preventing protein production, and preventing the cell from dividing (Bae, B. et al, 2013).

Figure 1. The pBAD-Gp2 construct.



The part was created by cloning a synthesised sequence block that contained Gp2, an RBS and the biobrick prefix and suffix, into an pBAD construct created by the 2014 Imperial iGEM team.


The construct effectively downregulates the growth of E. coli in response to arabinose, and does so in a reversible manner. We believe it is a good alternative to existing growth control methods, especially for controlling co-culture, for several reasons. You can read more about our characterisation data on our results page.



Key advantages
  1. Controlling cells in this way doesn’t require the usage of supplemented or minimal media, as in the case of antibiotics and auxotrophy.
  2. The system can easily be induced by L-arabinose, and switched off by D-glucose, both of which are non-toxic.
  3. Gp2 is particularly good for regulating population size in co-cultures, as it only affects the size of one population.

Reference

Bae, B., Davis, E., Brown, D., Campbell, E.A., Wigneshweraraj, S. and Darst, S.A., 2013. Phage T7 Gp2 inhibition of Escherichia coli RNA polymerase involves misappropriation of σ70 domain 1.1. Proceedings of the National Academy of Sciences, 110(49), pp.19772-19777.

BioBrick Registry Parts Table <groupparts>iGEM2016 Imperial_College</groupparts>