Team:Chiba/Project

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==What our system requires==
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*Communication module
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==How Our System Works==
==How Our System Works==

Revision as of 11:00, 24 October 2008

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Contents

Introduction

"Team : Chiba - E.coli time manager"
Chiba-logo.gif

  We control the timing of gene expression by using multiple signaling devices.To this end,we utilize molecules associated with Quorum sensing, a phenomenon that allows bacteria to communicate with each other.Our project uses two classes of bacteria: senders and receivers. Senders produce signaling molecules, and Receivers are activated only after a particular concentration of this molecule is reached.Although different quorum sensing species have slightly different signaling molecules, these molecules are not completely specific to their hosts and cross-species reactivity is observed (M.K Winson et al.FEMS Microbiology Letters,1998). Communication using non-endogenous molecules is less sensitive, and requires a higher signal concentration to take effect.This results in slower activation of receivers.


Motivation

Project Design

Controlling the time of a cell-to-cell signaling action

Our project uses two classes of bacteria: senders and receivers.Senders produce signaling molecules, and receivers are activated only after a particular concentration of this molecule is reached.The communication using non-endogenous molecules is less sensitive,and it requires higher signal concentration to take effect.This results in slower activation of receivers.

  • Quorum-Sensing Cross-talk

   AHLs produced by different bacteria differ only in the length of the acyl-chain moiety and substitution at position C-3.(BBa_F2620:Specificity)

  • LuxR/Plux mutants show
  1. a greater response to 3OC6HSL (C. H. Collins.et al.Mol.Microbiol.2005.)
  2. a increase in sensitivity to 3OC12HSL (B. Koch.et al.Microbiology (2005)).


About Quorum Sensing

  Quorum sensing is a cell-to-cell signaling action of bacteria. They detect the cell density of the same species and coordinate the expression behavior of their cells. Species of Gram-Negative signaling transfer molecules (so-called autoinducer) is a series of acyl homoserine lactone (AHL). The signals are synthesized from S-adenosylmethionine(SAM) by a synthase protein and once they have reached a threshold concentration,they bound to a transcriptional regulatory protein to induce expression of target genes.

More about Quorum Sensing

  

What our system requires

  • Communication module
  • Quick output

How Our System Works

Experiments

Quorum-Sensing Cross-talk

Method

  1. Transform Senders into E.coli strains(JW1908/XL10GOLD) and Receiver into E.coli strain(JW1908).
  2. Inoculated them independently in liquid media. Incubated at 37℃ 12h.
  3. Washed Senders and receiver.
  4. Mix them.
  5. Incubated at 37℃ or 30℃.
  6. Measured intensity of green fluorescence at regular time intervals.

Result

LuxR mutation

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