Bacterial Quorum SensingAPPLIED AND ENVIRONMENTAL MICROBIOLOGY, Jan. 2008, p. 437-445Many species of bacteria use quorum sensing tocoordinate their gene expression according to thelocal density of their population
Bacterial Quorum Sensing Many species of bacteria use quorum sensing to coordinate their gene expression according to the local density of their population. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Jan. 2008, p. 437–445
Quorum sensing was first observed in Vibrio fischeri, abioluminiscent bacterium that lives as a mutualisticsymbiont in the photophore (or light-producing organ)of the Hawaiian bobtail squid.When V. fischericells are free-living (or planktonic), theautoinducer is at low concentration and thus cells donotluminesce.However, when they are highly concentrated in thephotophore (about 1011 cells/ml) transcription ofluciferase is induced, leading to bioluminescence
Quorum sensing was first observed in Vibrio fischeri, a bioluminiscent bacterium that lives as a mutualistic symbiont in the photophore (or light-producing organ) of the Hawaiian bobtail squid. When V. fischeri cells are free-living (or planktonic), the autoinducer is at low concentration and thus cells do not luminesce. However, when they are highly concentrated in the photophore (about 1011 cells/ml) transcription of luciferase is induced, leading to bioluminescence
acylhomoserinelactone(acyl-HSLsynthase)synthesize3-oxohexanoylDL-homoserine lactonesLuxI(3OC6HSL)LuxRTo stabilizethetranscriptionfactor
LuxI 3-oxohexanoyl-DL-homoserine lactones (3OC6HSL) acylhomoserine lactone (acyl-HSL synthase) LuxR synthesize To stabilize the transcription factor
Results and DiscussionThe modeling suggests:(i) A threshold response results from positive feedback on a single, noncooperatively boundregulatory element (either a LuxR or Luxlhomolog)
Results and Discussion The modeling suggests: (i) A threshold response results from positive feed back on a single, noncooperatively bound regulatory element (either a LuxR or LuxI homolog)
Bistability results from either positive feedback1on two noncooperatively bound regulatoryelementsorpositivefeedbackononeormorecooperativelyboundregulatoryelements
(ii) Bistability results from either positive feedback on two noncooperatively bound regulatory elements or positive feedback on one or more cooperatively bound regulatory elements