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PRODID:-//Memento EPFL//
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SUMMARY:Why are chemotaxis receptors clustered but other receptors aren’
 t?
DTSTART:20150323T161500
DTEND:20150323T171500
DTSTAMP:20260428T152742Z
UID:39cc659c627cf5505daac35a39dcdf2196b9559b68963d35843b5349
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Ned Wingreen\, Princeton University\nThe chemotaxis netw
 ork of bacteria such as E. coli is remarkable for its sensitivity to minut
 e relative changes in chemical concentrations in the environment. Much of 
 this acute sensitivity can be traced to the collective behavior of teams o
 f chemoreceptors on the cell surface. Coupled with a system for adaptation
 \, the advantage for chemotaxis is gain – i.e.\, small relative changes 
 in chemical concentrations are transduced into large relative changes in s
 ignaling activity. However\, something is troubling about this simple expl
 anation: in addition to providing gain\, the coupling of receptors into te
 ams also increases noise\, and the net result is a decrease in the signal-
 to-noise ratio of the network. Why then are chemoreceptors observed to for
 m cooperative teams? I will present a novel hypothesis that the run-and-tu
 mble chemotactic strategy of bacteria leads to a “noise threshold”\, b
 elow which noise does not significantly decrease chemotactic velocity\, bu
 t above which noise dramatically decreases this velocity. I will also disc
 uss other systems in E. coli that call for a biophysical analysis.
LOCATION:Auditoire CE 1 http://plan.epfl.ch/?zoom=20&recenter_y=5864182.50
 561&recenter_x=731299.44535&layerNodes=fonds\,batiments\,labels\,informati
 on\,parkings_publics\,arrets_metro\,transports_publics&floor=1&q=ce1
STATUS:CONFIRMED
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