Project description:We report the full transcriptome (RNA-Seq) of Vibrio fischeri ES114 in rich medium, seawater, and after venting from the Hawaiian bobtail squid Euprymna scolopes. We also report the effects of ribodepletion on low-biomass samples, down to input amount of 1ng total RNA.
2016-04-26 | GSE80607 | GEO
Project description:Microbial diversity in Mauritius seawater
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:Seawater exposure to the gram negative marine bacterium Vibrio diazotrophicus induces a robust cellular response in sea urchin larvae that includes the migration of pigment cells to the gut epithelium, changes in cell behavior and altered gut morphology (Ho et al., 2016; PMID 27192936). To investigate the transcriptional underpinnings of this response, whole transcriptome sequencing was performed on mRNA isolated from larval samples collected at 0, 6, 12 and 24 hr of exposure to V. diazotrophicus. The morphological simplicity of the sea urchin larva provides a systems-level model for identifying biologically relevant transcriptional state changes in response to dysbiosis in the gut lumen.
Project description:Maintaining marine salinities in inland aquaculture systems can be cost-prohibitive. As such, there has been an emphasis on the identification of marine species that can be reared at low salinities. The Florida pompano (Trachinotus carolinus) is a popular sportfish that can survive in salinities as low as 5 ppt and has been identified as a potential target species for commercial production. Vibrio spp., bacterial pathogens ubiquitous in aquaculture systems, are capable of quickly decimating aquaculture populations. However, there is limited data available on the effects of salinity influences on Vibrio susceptibility in juvenile Florida pompano. This study investigated the influence of lowered salinity on the immune response of juvenile Florida pompano exposed to Vibrio across a 14-day period through assessment of transcriptomic changes, fatty acid biosynthesis, and identification of internal and external signs of vibriosis. During the experimental period, there were no differences in osmoregulatory or immune related gene expression, no obvious signs of vibriosis, and no changes in fatty acid biosynthesis in fish exposed to 8, 12, 20, or 28 ppt seawater. These results suggest juvenile Florida pompano are resilient to salinity changes and exhibit baseline molecular machinery capable of responding to pathogenic challenges across a range of salinities, making them strong candidates for rearing in inland aquaculture.
Project description:The bioluminescent bacterium Vibrio fischeri forms a mutually beneficial symbiosis with the Hawaiian bobtail squid, Euprymna scolopes, in which the bacteria, housed inside a specialized light organ, produce light used by the squid in its nocturnal activities. Upon hatching, E. scolopes juveniles acquire V. fischeri from the seawater through a complex process that requires, among other factors, chemotaxis by the bacteria along a gradient of N-acetylated sugars into the crypts of the light organ, the niche in which the bacteria reside. Once inside the light organ, V. fischeri transitions into a symbiotic, sessile state in which the quorum-signaling regulator LitR induces luminescence. In this work we show that expression of litR and luminescence are repressed by a homolog of the V. cholerae virulence factor TcpP, which we have named HbtR. Further, we demonstrate that LitR represses genes involved in motility and chemotaxis into the light organ and activates genes required for exopolysaccharide production. Importance: TcpP homologs are widespread throughout the Vibrio genus; however, the only protein in this family described thus far is a V. cholerae virulence regulator. Here we show that HbtR, the TcpP homolog in V. fischeri, has both a biological role and regulatory pathway completely unlike that in V. cholerae. Through its repression of the quorum-signaling regulator LitR, HbtR affects the expression of genes important for colonization of the E. scolopes light organ. While LitR becomes activated within the crypts, and upregulates luminescence and exopolysaccharide genes and downregulates chemotaxis and motility genes, it appears that HbtR, upon expulsion of V. fischeri cells into seawater, reverses this process to aid the switch from a symbiotic to a planktonic state. The possible importance of HbtR to the survival of V. fischeri outside of its animal host may have broader implications for the ways in which bacteria transition between often vastly different environmental niches.