Project description:Acyl-homoserine lactone (acyl-HSL) quorum sensing was first discovered in Vibrio fischeri where it serves as a key control element of the seven-gene luminescence (lux) operon. Since this initial discovery, other bacteria have been shown to control hundreds of genes by acyl-HSL quorum sensing. Until recently, it has been difficult to examine the global nature of quorum sensing in V. fischeri. However, the complete genome sequence of V. fischeri is now available and this has enabled us to use transcriptomics to identify quorum-sensing regulated genes and to study the quorum-controlled regulon of this bacterium. In this study, we used DNA microarray technology to identify over two-dozen V. fischeri genes regulated by the quorum sensing signal N-3-oxohexanoyl-L-homoserine lactone (3OC6-HSL). Keywords: Comparison of transcriptome profiles
Project description:The marine bacterium Vibrio fischeri requires flagellar motility to undergo symbiotic initiation with its host, the Hawaiian bobtail squid Euprymna scolopes. We sought to identify the genes activated by the sigma54-dependent flagellar master regulator, FlrA, in V. fischeri, thereby determining the flagellar regulon in this model symbiont.
Project description:The marine bacterium Vibrio fischeri requires flagellar motility to undergo symbiotic initiation with its host, the Hawaiian bobtail squid Euprymna scolopes. We sought to identify the genes activated by the sigma54-dependent flagellar master regulator, FlrA, in V. fischeri, thereby determining the flagellar regulon in this model symbiont. We performed microarray analysis on wild-type Vibrio fischeri ES114 and a flrA deletion mutant, DM159, grown to mid-log phase in seawater tryptone, a condition in which cells are highly motile (two biological replicates per condition).
Project description:The bioluminescent bacterium Vibrio fischeri initiates a specific, persistent symbiosis in the light organ of the squid Euprymna scolopes. During the early stages of colonization, V. fischeri is exposed to host-derived nitric oxide (NO). While NO can be both an antimicrobial component of innate immunity and a common signaling molecule of eukaryotes, its roles in beneficial host-microbe associations remain undescribed. V. fischeri encodes HnoX, a member of a family of bacterial NO-binding proteins of unknown function. We hypothesized that HnoX acts as a NO sensor that is involved in regulating symbiosis-related genes during initiation of symbiosis. With an aim to discover the genes whose regulations respond to NO signal, and in an HnoX-mediated fashion in particular, we carried out a whole-genome expression study on the wild-type and an insertional mutant of hnoX.