title: Quorum sensing regulation in Aeromonas hydrophila.
abstract: We present detailed results on the C4-HSL-mediated quorum sensing (QS) regulatory system of the opportunistic Gram-negative bacterium Aeromonas hydrophila. This bacterium contains a particularly simple QS system that allows for a detailed modeling of kinetics. In a model system (i.e., the Escherichia coli monitor strain MH205), the C4-HSL production of A. hydrophila is interrupted by fusion of gfp(ASV). In the present in vitro study, we measure the response of the QS regulatory ahyRI locus in the monitor strain to predetermined concentrations of C4-HSL signal molecules. A minimal kinetic model describes the data well. It can be solved analytically, providing substantial insight into the QS mechanism: at high concentrations of signal molecules, a slow decay of the activated regulator sets the timescale for the QS regulation loop. Slow saturation ensures that, in an A. hydrophila cell, the QS system is activated only by signal molecules produced by other A. hydrophila cells. Separate information on the ahyR and ahyI loci can be extracted, thus allowing the probe to be used in identifying the target when testing QS inhibitors.
authors.affiliation: Elektro, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Garde
authors.forename: Thomas
authors.initials: T
authors.lastname: Bjarnsholt
authors.forename: Michael
authors.initials: M
authors.lastname: Givskov
authors.forename: Tim Holm
authors.initials: TH
authors.lastname: Jakobsen
authors.forename: Morten
authors.initials: M
authors.lastname: Hentzer
authors.forename: Anetta
authors.initials: A
authors.lastname: Claussen
authors.forename: Kim
authors.initials: K
authors.lastname: Sneppen
authors.forename: Jesper
authors.initials: J
authors.lastname: Ferkinghoff-Borg
authors.forename: Thomas
authors.initials: T
authors.lastname: Sams
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000502:physiology; D016980:Aeromonas hydrophila / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology; D005798:Genes, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C108088:AhyRI protein, Aeromonas; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C092312:N-butyrylhomoserine lactone; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D015107:4-Butyrolactone