Project description:Bacteria in nature are widely exposed to differential fluid shears which are often a trigger for phenotypic switches. The latter mediates transcriptional and translation remodeling of cellular metabolism impacting among others virulence, antimicrobial resistance and stress resistance. In this study, we evaluated the role of fluid shear on phenotypic switch in an acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus M0904 strain under both in vitro and in vivo conditions. The results showed that V. parahaemolyticus M0904 grown at lower shaking speed (110 min-1 constant agitation, M0904/110), causing low fluid shear, develop cellular aggregates or floccules. These cells increased levan production (as verified by concanavalin binding) and developed differentially stained colonies on Congo Red agar plates and resistance to antibiotics. In addition, the phenotypic switch causes a major shift in the protein secretome. At 120 min-1 (M0904/120), PirA/B toxins are mainly produced, while at 110 min-1 PirA/B toxin production is stopped and an alkaline phosphatase PhoX becomes the dominant protein in the protein secretome. These observations are matched with a very strong reduction in virulence of M0904/110 towards two crustacean larvae, namely Artemia and Macrobrachium. Taken together, our study provides substantial evidence for the existence of two phenotypic forms in AHPND Vibrio parahaemolyticus strains displaying differential phenotypes that could be of interest in understanding the epidemiology of AHPND under aquaculture conditions. It might provide the basis for AHPND control by steering phenotypes.
Project description:Vibrio parahaemolyticus is a Gram-negative bacterium commonly found in marine and estuarine environments. Acute hepatopancreatic necrosis disease (AHPND) caused by this bacterium is an ongoing problem among shrimp farming industries. V. parahaemolyticus proteins PirA and PirB have been determined to be major virulence factors that induce AHPND. In this study, Pacific white shrimp (Litopenaeus vannamei) were challenged with recombinant PirA and PirB by a reverse gavage method and then at 30 m, 1, 2, 4, and 6 h time points, the hepatopancreas of five individual shrimp were removed and placed into RNA later. We conducted RNA sequencing of the hepatopancreas samples from a no PirA/B control (n = 5) and PirA/B-treated shrimp at the different time intervals (n=5). We evaluated the different gene expression patterns between the time groups to the control with a focus on identifying differences in innate immune function.
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.
2020-06-18 | GSE107696 | GEO
Project description:Transcriptome of Vibrio parahaemolyticus strain AHPND
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: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.
