Project description:Vibrio campbellii BAA-1116 was used as a Harveyi clade model organism to determine the impact of indole signaling on virulence. Gene expression analysis of V. campbellii grown in LB35 broth with or without 100 μM indole revealed that indole decreased: (1) V. campbellii virulence in shrimp and prawn challenge assays, (2) exopolysaccharide production, and (3) swimming motility. The results also indicated that indole inhibits quorum sensing-regulated bioluminescence and blocks the three-channel quorum sensing system by interfering with quorum sensing signal transduction.
Project description:Objectives: determination of transcription start sites in Vibrio harveyi genome and discovery of new transcripts Methods: we performed differential seqencing of total RNA isolated from o.n. control Vibrio harveyi cultures. Sample treatment with Terminator EXonuclease (TEX) allowed differenciation of primary and secondary transcripts, helping in the definition of transcription start sites (TSS) Results: by data-mining RNA-seq data and performing some Northern Blot experiments we were able to detect new putative small-RNAs, along with these results, a more deep analisys of our RNA-seq data will give futher insight into genetic organization of Vibrio harveyi genome to help in its investigation
Project description:Vibrio harveyi is a major bacterial pathogen that can cause fatal vibriosis in Chinese tongue sole (Cynoglossus semilaevis). To comprehend the molecular mechanisms of C. semilaevis host response against V. harveyi infection, we performed transcriptome (RNA-seq) analysis of C. semilaevis from resistant family and susceptible family.
Project description:In this research, we used RNA-sequencing technology to detect genome-wide differentially expressed genes in spleen and gill of Vibrio harveyi -infected Takifugu rubripes.This high-throughput sequencing could help us to understand new mechanisms of action of V. harveyi induced aquaculture fish disease.
Project description:Quorum sensing controls hundreds of genes in vibrios required for cell density-specific behaviors, including bioluminescence, biofilm formation, competence, secretion, and motility. The central regulator in the quorum sensing pathway in vibrios is LuxR/HapR, which directly regulates >100 genes in the 625-gene regulon of Vibrio harveyi. Among these directly regulated genes are 15 transcription factors, which we predicted would comprise the second tier in the hierarchy of the quorum sensing regulon. To better study the mechanism of regulation of the quorum sensing network, we mapped all transcriptional start sites in V. harveyi using dRNA-seq. From these data, we determined the relative position of LuxR binding sites in the promoters of genes directly regulated by LuxR. We confirmed that LuxR directly binds to the promoters of the genes encoding transcription factors and quantified the extent of LuxR activation or repression of transcript levels. Finally, we determined the individual regulons for a subset of transcription factors that have not been previously studied. For regulators such as LysR- or AsnC/Lrp-type transcription factors, the regulons contained >100 genes that contained both unique and overlapping genes with the LuxR regulon. These data support a model in which LuxR directly regulates other transcription factors, which act to further alter the second tier of the gene expression cascade producing cell density behaviors in V. harveyi.
Project description:Vibrio species represent one of the most diverse genera of marine bacteria known for their ubiquitous presence in natural aquatic systems. Several members of this genus including Vibrio harveyi are receiving increasing attention lately because they are becoming a source of health problems, especially for some marine organisms widely used in sea food industry. To learn about adaptation changes triggered by V. harveyi during its long-term persistence at elevated temperatures, we studied adaptation of this marine bacterium in sea water microcosms at 30 oC that closely mimicks the upper limits of sea surface temperatures recorded around the globe.
