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SUMMARY:Plenary Lecture 1: Understanding bacterial communication and coope
 ration: combinatorial quorum-sensing - Brown\, S (University of Edinburgh)
DTSTART:20141027T133000Z
DTEND:20141027T143000Z
UID:TALK55691@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Quorum sensing (QS) is a cellcell communication system that co
 ntrols gene expression in many bacterial species\, mediated by diffusible 
 signal molecules. Although the intracellular regulatory mechanisms of QS a
 re often well-understood\, the functional roles of QS remain controversial
 . In particular\, the use of multiple signals by many bacterial species po
 ses a serious challenge to current functional theories. Here\, we address 
 this challenge by showing that bacteria can use multiple QS signals to inf
 er both their social (density) and physical (mass-transfer) environment. A
 nalytical and evolutionary simulation models show that the detection of\, 
 and response to\, complex social/physical contrasts requires multiple sign
 als with distinct half-lives and combinatorial (nonadditive) responses to 
 signal concentrations. We test these predictions using the opportunistic p
 athogen Pseudomonas aeruginosa and demonstrate significant differences in 
 signal decay between its two primary si gnal molecules\, as well as divers
 e combinatorial responses to dual-signal inputs. QS is associated with the
  control of secreted factors\, and we show that secretome genes are prefer
 entially controlled by synergistic AND-gate responses to multiple signal i
 nputs\, ensuring the effective expression of secreted factors in high-dens
 ity and low mass-transfer environments. Our results show that combinatoria
 l communication is not restricted solely to primates and is computationall
 y achievable in single-celled organisms. \n
LOCATION:Seminar Room 1\, Newton Institute
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