Project description:Vibrio parahaemolyticus an emerging pathogen that is a causative agent of foodborne gastroenteritis when raw or undercooked seafood is consumed. Previous microarray data using a Vibrio parahaemolyticus RIMD2210633 chip has shown the master quorum-sensing regulator OpaR controls virulence, type III and type VI secretion systems, and flagellar and capsule production genes. In a parallel study, RNA-Seq was used to comparatively study the transcriptome changes of wild type Vibrio parahaemolyticus BB22 and a ΔopaR strain directly. Differences in mRNA expression were analyzed using next generation Illumina sequencing and bioinformatics techniques to align and count reads. A comparison with the previous microarray data showed good correlation between the shared genes. The RNA-Seq offered an insight into control of genes specific to the Vibrio parahaemolyticus BB22 strain as well as a new look at the sRNAs that are expressed. Eleven transcriptional regulators with greater than 4 fold regulation in the previous microarray study and 2 fold regulation in the RNA-Seq analysis, were chosen to validate the data using qRT-PCR and further characterized with electrophoretic mobility shift assays (EMSAs) to determine if they are direct targets of OpaR. The transcription factors chosen play key roles in virulence, surface motility, cell to cell interactions, and cell surface characteristics. One small RNA was identified in the RNA-Seq data to be quorum-sensing controlled and unidentified by other programs. The RNA-Seq data has aided in understanding and elucidating the hierarchy of quorum-sensing control of OpaR in Vibrio parahaemolyticus. The wild type Vibrio parahaemolyticus BB22 strain LM5312 and an opaR deletion strain LM5674 were analyzed for mRNA expression using RNA-Seq.
Project description:Vibrio parahaemolyticus an emerging pathogen that is a causative agent of foodborne gastroenteritis when raw or undercooked seafood is consumed. Previous microarray data using a Vibrio parahaemolyticus RIMD2210633 chip has shown the master quorum-sensing regulator OpaR controls virulence, type III and type VI secretion systems, and flagellar and capsule production genes. In a parallel study, RNA-Seq was used to comparatively study the transcriptome changes of wild type Vibrio parahaemolyticus BB22 and a ΔopaR strain directly. Differences in mRNA expression were analyzed using next generation Illumina sequencing and bioinformatics techniques to align and count reads. A comparison with the previous microarray data showed good correlation between the shared genes. The RNA-Seq offered an insight into control of genes specific to the Vibrio parahaemolyticus BB22 strain as well as a new look at the sRNAs that are expressed. Eleven transcriptional regulators with greater than 4 fold regulation in the previous microarray study and 2 fold regulation in the RNA-Seq analysis, were chosen to validate the data using qRT-PCR and further characterized with electrophoretic mobility shift assays (EMSAs) to determine if they are direct targets of OpaR. The transcription factors chosen play key roles in virulence, surface motility, cell to cell interactions, and cell surface characteristics. One small RNA was identified in the RNA-Seq data to be quorum-sensing controlled and unidentified by other programs. The RNA-Seq data has aided in understanding and elucidating the hierarchy of quorum-sensing control of OpaR in Vibrio parahaemolyticus.
Project description:The quorum regulatory cascade is poorly characterized in Vibrio parahaemolyticus, in part because swarming and pathogenicity - the hallmark traits of the organism - are repressed by this scheme of gene control. As a consequence, many isolates appear silenced for quorum sensing via phase variation. In these studies, we examine a swarm proficient, virulent strain and find an altered function allele of the central quorum regulator luxO. We use this allele, which produces a constitutively active LuxO, to probe the upstream elements of the pathway and demonstrate their functionality for the first time. We find that the state of luxO affects expression of three small regulatory RNAS (Qrrs) and the activity of a translational fusion in opaR, the central output regulator. We use microarray profiling to determine the OpaR regulon, which was found to encompass ~5.2% of the genome. The quorum sensing proficient strain seems adapted for a sessile, community lifestyle; it is competent to uptake DNA, produces much capsular polysaccharide, has a high level of c-di-GMP, and strongly expresses one type six secretion system. Expressing the entire surface sensing regulon and numerous methyl accepting chemotaxis proteins, the quorum-disrupted cell type seems prepared for a mobile lifestyle. It is also cytotoxic to host cells in co-culture and expresses distinct type six as well as type three secretion systems. Thus, the scope and nature of the genes in the OpaR regulon provide many clues to the distinguishing traits of this Vibrio species as well as to the quite divergent survival strategies of the quorum ON/OFF phase variants The gene expression profiles of different strains of Vibrio parahaemolyticus cells grown on rich medium and compared using Affymetrix custom microarrays.
Project description:The quorum regulatory cascade is poorly characterized in Vibrio parahaemolyticus, in part because swarming and pathogenicity - the hallmark traits of the organism - are repressed by this scheme of gene control. As a consequence, many isolates appear silenced for quorum sensing via phase variation. In these studies, we examine a swarm proficient, virulent strain and find an altered function allele of the central quorum regulator luxO. We use this allele, which produces a constitutively active LuxO, to probe the upstream elements of the pathway and demonstrate their functionality for the first time. We find that the state of luxO affects expression of three small regulatory RNAS (Qrrs) and the activity of a translational fusion in opaR, the central output regulator. We use microarray profiling to determine the OpaR regulon, which was found to encompass ~5.2% of the genome. The quorum sensing proficient strain seems adapted for a sessile, community lifestyle; it is competent to uptake DNA, produces much capsular polysaccharide, has a high level of c-di-GMP, and strongly expresses one type six secretion system. Expressing the entire surface sensing regulon and numerous methyl accepting chemotaxis proteins, the quorum-disrupted cell type seems prepared for a mobile lifestyle. It is also cytotoxic to host cells in co-culture and expresses distinct type six as well as type three secretion systems. Thus, the scope and nature of the genes in the OpaR regulon provide many clues to the distinguishing traits of this Vibrio species as well as to the quite divergent survival strategies of the quorum ON/OFF phase variants
Project description:Vibrio parahaemolyticus is the leading bacterial cause for seafood-related gastroenteritis worldwide. As an intestinal pathogen, V. parahaemolyticus competes with other commensal bacteria for the same pool of nutrients. The major source of nutrition for intestinal bacteria is intestinal mucus. We wanted to determine the expression profile of wild-type V. parahaemolyticus in mouse intestinal mucus and then perform a differential expression analysis in a ∆luxO deletion mutant, in which the high cell density quorum sensing regulator OpaR is constitutively expressed and low cell density regulator AphA is repressed.
Project description:Comparative proteomics to identify proteins found in the media of Vibrio parahaemolyticus RIMD 2210633 bacteria with an active T6SS2 compared to bacteria with inactive T6SS2. Bacteria with an active T6SS2 are Vibrio parahaemolyticus RIMD 2210633 inwhich hcp1 was deleted to inactivate T6SS1. T6SS2 inactive bacteria are the former strain with an additional deletion in hcp2. Both strains express TfoX from an arabinose-inducible plasmid to induce T6SS2 activity.
Project description:Compare the secreted proteins of a wild-type Vibrio parahaemolyticus strain with those of a mutant in hcp2, rendering the T6SS2 inactive
Project description:In order to gain a better understanding of the impact of Vibrio parahaemolyticus infection on genetic regulation of Litopenaeus vannamei,we performed a transcriptome analysis in the hepatopancreas of Litopenaeus vannamei challenged with Vibrio parahaemolyticus, using the Illumina HiSeq 2500 platform.
Project description:In order to gain a better understanding of the impact of Vibrio parahaemolyticus infection on genetic regulation of Litopenaeus vannamei,we performed a miRNA-seq analysis in the hepatopancreas of Litopenaeus vannamei challenged with Vibrio parahaemolyticus, using the Illumina HiSeq 2500 platform.