Difference between revisions of "Team:IIT Madras"

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{{IIT_Madras}}
 
{{IIT_Madras}}
 
<html>
 
<html>
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<h2> Welcome to the wiki page of IIT Madras for iGEM 2015! </h2>
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<p>As you can see it's not ready yet. But don't worry it will be! A short project description is available under Project -> Description.</p>
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<h2>The Problem</h2>
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<h2>Our Solution</h2>
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<p>Most pathogenic microbes secrete quorum sensing (QS) molecules like AHL, AI-2 when present in high
 +
cell density. QS molecules are sensed by receptor proteins on the cell surface of pathogens. These
 +
signaling molecules help them in regulating their communal activities.</p>
 +
 
 +
<p>In the lab, we will be using E.Coli DH5alpha strain as pathogenic model. DH5alpha does not secrete
 +
quorum sensing molecules natively. Therefore, we will genetically modify E. coli DH5alpha strain to
 +
release Auto-Inducer-2, a signaling molecule.[Ref. 4] We do this so as to create a recombinant that
 +
mimics many pathogenic bacterium that secrete quorum sensing molecules.</p>
 +
 
 +
<p>We will be using Lactococcus lactis MG1363 strain as a receiver. It has a simple circuit to detect high and
 +
low cell density of pathogens and release the appropriate molecules. L. lactis activates the expression
 +
of Alyteserin (antu-microbial peptide) at high cell density and NAly (neutralizing anit-microbila peptide)
 +
at low cell density. The precise mechanism with the genes involved is explained below.</p>
 +
 
 +
<p>At low cell density, luxP,luxQ,luxU receptor proteins act as kinases that results in the phosphorylation
 +
of luxO (luxO-P) that activates qrr1-5 sRNAs with the help of sigma54 RNAP subunit factor, qrr RNAs degrade
 +
the mRNA of LuxR which has been found to activate and repress a number of gene when expressed in the cell.[Ref. 3] </p>
 +
 
 +
<p>While at high cell density, the same receptor proteins (LuxP,Q,U) acts as phosphatases which removes
 +
the phosphate from LuxO-P and this results into the higher expression of LuxR gene.[Ref. 3]</p>
 +
 
 +
<p>Through this project, we aim to investigate a few questions and hypothesis:</p>
 +
<ol>
 +
<li> Is bacterial resistance a big cause of concern when using antimicrobial peptides?</li>
 +
<li> Are oscillations in cell population observed when our system is used? Are the oscillations damped?</li>
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<li> How effective is the activity of NAly in neutralising the effects of Alyteserin?</li>
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</ol>
 +
 
  
 
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<h4>Inspiration</h4>
 
<h4>Inspiration</h4>
 
<p> You can also view other team wikis for inspiration! Here are some examples:</p>
 
<p> You can also view other team wikis for inspiration! Here are some examples:</p>
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<li> <a href="https://2014.igem.org/Team:SCU-China"> 2014 SCU-China </a></li>
 
<li> <a href="https://2014.igem.org/Team:SCU-China"> 2014 SCU-China </a></li>
 
</ul>
 
</ul>
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<h4> Uploading pictures and files </h4>
 
<h4> Uploading pictures and files </h4>
 
<p> You can upload your pictures and files to the iGEM 2015 server. Remember to keep all your pictures and files within your team's namespace or at least include your team's name in the file name. <br />
 
<p> You can upload your pictures and files to the iGEM 2015 server. Remember to keep all your pictures and files within your team's namespace or at least include your team's name in the file name. <br />

Revision as of 06:44, 15 July 2015

The Problem

Our Solution

Most pathogenic microbes secrete quorum sensing (QS) molecules like AHL, AI-2 when present in high cell density. QS molecules are sensed by receptor proteins on the cell surface of pathogens. These signaling molecules help them in regulating their communal activities.

In the lab, we will be using E.Coli DH5alpha strain as pathogenic model. DH5alpha does not secrete quorum sensing molecules natively. Therefore, we will genetically modify E. coli DH5alpha strain to release Auto-Inducer-2, a signaling molecule.[Ref. 4] We do this so as to create a recombinant that mimics many pathogenic bacterium that secrete quorum sensing molecules.

We will be using Lactococcus lactis MG1363 strain as a receiver. It has a simple circuit to detect high and low cell density of pathogens and release the appropriate molecules. L. lactis activates the expression of Alyteserin (antu-microbial peptide) at high cell density and NAly (neutralizing anit-microbila peptide) at low cell density. The precise mechanism with the genes involved is explained below.

At low cell density, luxP,luxQ,luxU receptor proteins act as kinases that results in the phosphorylation of luxO (luxO-P) that activates qrr1-5 sRNAs with the help of sigma54 RNAP subunit factor, qrr RNAs degrade the mRNA of LuxR which has been found to activate and repress a number of gene when expressed in the cell.[Ref. 3]

While at high cell density, the same receptor proteins (LuxP,Q,U) acts as phosphatases which removes the phosphate from LuxO-P and this results into the higher expression of LuxR gene.[Ref. 3]

Through this project, we aim to investigate a few questions and hypothesis:

  1. Is bacterial resistance a big cause of concern when using antimicrobial peptides?
  2. Are oscillations in cell population observed when our system is used? Are the oscillations damped?
  3. How effective is the activity of NAly in neutralising the effects of Alyteserin?