Scientific Colloquium
January 23, 2004


The research in my laboratory focuses on the molecular mechanisms that bacteria use for intercellular communication.  The bacterial communication phenomenon that we study is called quorum sensing.  Quorum sensing is the control of gene expression in response to cell density.   Quorum sensing bacteria produce, release and detect hormone-like molecules called autoinducers that accumulate in the environment as the bacterial cell density increases.  When a threshold stimulatory concentration of autoinducer is detected, a signal transduction cascade is initiated and results in an alteration in gene expression.  It has recently been shown that hundreds of species of bacteria produce and detect autoinducers to regulate gene expression in response to changing cell density.  Quorum sensing controls many diverse bacterial functions.  These processes include; virulence factor production, conjugative DNA transfer, symbiosis, and antibiotic production.  Presumably, quorum sensing enables bacteria to coordinate their behavior, to act like multi-cellular organisms, and to acquire the benefits of cooperative activity.