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Vibrio campbellii DS40M4 is a tractable model strain that diverges from the canonical quorum-sensing regulatory circuit in vibrios

ABSTRACT: Vibrio campbellii BB120 (ATCC BAA-1116, previously designated as Vibrio harveyi) is a fundamental model strain for studying population density-based cell-to-cell communication, known as quorum sensing, among gram-negative bacteria. In V. campbellii BB120, sensing of autoinducers at high cell densities activates the expression of the master transcriptional regulator, LuxR, which controls the expression of genes involved in group behaviors. Unlike BB120, the Vibrio campbellii environmental isolate DS40M4 was recently shown to be capable of natural transformation, a process by which bacteria take up exogenous DNA and incorporate it into their genome via homologous recombination. Here, we compare other phenotypes between DS40M4 and BB120. We find that DS40M4 has a faster growth rate and stronger type VI secretion-mediated cell killing, whereas BB120 forms more robust biofilms and is bioluminescent. We exploited the power of natural transformation to rapidly generate >30 mutant strains to explore the function of DS40M4-encoded homologs of the BB120 quorum-sensing system. Our results show that DS40M4 has a similar quorum-sensing circuit to BB120 but with three distinct differences: 1) DS40M4 lacks the canonical HAI-1 autoinducer LuxM synthase but has an active LuxN receptor, 2) the quorum regulatory small RNAs (Qrrs) are not solely regulated by autoinducer signaling through the response regulator LuxO, and 3) the DS40M4 LuxR regulon is <100 genes, which is relatively small compared to the >400 genes regulated in BB120. This work illustrates that DS40M4 is a tractable and relevant model strain for studying quorum-sensing phenotypes in Vibrio campbellii.

ORGANISM(S): Vibrio campbellii

PROVIDER: GSE147616 | GEO | 2021/06/28

REPOSITORIES: GEO

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Indole signaling and (micro)algal auxins decrease the virulence of Vibrio campbellii, a major pathogen of aquatic organisms

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2013-05-31 | E-GEOD-46223 | biostudies-arrayexpress

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Project description:The selective advantage of bioluminescence in bacterial cells that do not form symbiotic relationships with aquatic animals is still not known. Some evidence suggests that bioluminescence plays a role in DNA repair by a photoreactivation process (Czyz 2000) and that non-bioluminescent strains are less virulent than their bioluminescent isogenic counterparts (Ruwandeepika 2010). All hypotheses to date suggest bioluminescence associated or mediated changes in gene expression, yet the evidence for this does not exist. In this study, we generated an in-frame luxAB deletion mutant (the two contiguous genes that encode for bacterial luciferase) and compared its mid-log phase gene expression profile with that of the wild type spontaneous streptomycin resistant (STR) V. campbellii BAA-1116 parental strain from which it was derived. Both mid-log phase transcriptomes were elucidated using custom designed whole genome microarrays (520694F, Affymetrix) to determine the effect luciferase has on V. campbellii gene expression. The virulence phenotypes of both strains were also subsequently tested in Artemia franciscana challenge experiments. Three biological replicates of the wild type (STR) and luxAB deletion mutant of V. campbellii BAA-1116 were grown to mid-log phase (15 h, 200 rpm, 30M-BM-0C, in 25 mL autoinducer bioassay medium) and total RNA was extracted from 1.0E+9 cells. Messenger RNA was isolated from the total RNA extracts treated with DNase, labeled with biotin, fragmented and hybridized to V. campbellii BAA-1116 whole genome microarrays (520694F, Affymetrix).

2012-08-31 | E-GEOD-34741 | biostudies-arrayexpress

van Kessel KM810 v JV55

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2013-02-20 | E-GEOD-44196 | biostudies-arrayexpress

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