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SUMMARY:Signal processing in bacterial chemotaxis - Victor Sourjik
DTSTART:20060303T141500Z
DTEND:20060303T151500Z
UID:TALK4688@talks.cam.ac.uk
CONTACT:Duncan Simpson
DESCRIPTION:Signal amplification and robustness against perturbations are 
 common to most biological networks. We studied these features in chemotaxi
 s on Escherichia coli\, the most thoroughly studied model system for signa
 l transduction. Despite its apparent simplicity\, the chemotaxis pathway s
 hows extremely high sensitivity\, wide dynamic range and surprising robust
 ness. To better understand these features\, we use several fluorescence mi
 croscopy techniques\, including fluorescence resonance energy transfer (FR
 ET)\, to quantitatively characterize signal processing by the pathway in v
 ivo. We showed that chemotactic stimuli are amplified and integrated by th
 e chemoreceptor clusters\, which work as large allosteric complexes. We al
 so observed strong cell-to-cell variation in the levels of chemotaxis prot
 eins\, and investigated the effects of such variation on signal transducti
 on. Combining theoretical and experimental analysis\, we demonstrated that
  the pathway is robust to the observed gene expression noise and determine
 d the network design features responsible for this robustness.\n
LOCATION:IRC in Superconductivity Seminar Room\, Cavendish Laboratory
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