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: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: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:Comparative transcriptional mRNA profiles were generated of bacterial pathogen Vibrio parahaemolyticus under conditions that induce activity of virulence factor type III secretion system 1 (T3SS1). Induction conditions included growth of the bacteria in Dulbecco's Modified Eagle Medium (DMEM), overexpression of transcriptional activator exsA and contact with HeLa cells in Hank's Balanced Salt Solution (HBSS), while non-inducing conditions included growth in Luria-Bertani medium supplemented with 2.5% (w/v) NaCl (LB-S) and overexpression of transcriptional anti-activator exsD. Transcriptome profiles of induction conditions were cross-compared against background non-inducing conditions and time points during HeLa cell infection (2 hr, 3 hr, 4 hr, 6 hr, 8 hr) were compared against pre-infection (0 hr) to identify genes important in T3SS1 activity and pathogenesis. Duplicate mRNA transcriptome profiles of V. parahaemolyticus grown in T3SS1 inducing (DMEM, exsA expression) and non-inducing (LB-S, exsD expression) conditions as well as during HeLa cell infection (0 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr) were generated by deep sequencing using an Illumina MiSeq
Project description:To investigate low-temperature tolerance of the bacterium, three in-frame gene deletion mutants of VpacspA and VpacspD were constructed using homologous recombination method. When compared to the wild type strain, the growth of ΔVpacspA mutant was strongly repressed at 10 0C, whereas the deletion of VpacspD gene greatly activated the bacterium growth at the low temperature. Transcriptome data revealed that 12.4% of the expressed genes in V. parahaemolyticus CHN25 was significantly changed in ΔVpacspA mutant grown at 10 0C, including those involved in amino acid degradation, ATP-binding cassette (ABC) transporters, secretion systems, sulfur and glycerophospholipid metabolisms, whereas the low temperature elicited 10.0% of the genes from ΔVpacspD mutant, such as phosphotransferase system, nitrogen and amino acid metabolisms. Moreover, the major changed metabolic pathways in dual-gene deletion mutant (ΔVpacspAD) differed radically from those in single-gene mutants. Comparison of transcriptome profiles further revealed a number of differentially expressed genes shared among the three mutants, as well as regulators specifically, coordinately and or antagonistically regulating in the adaptation of V. parahaemolyticus CHN25 to the low-temperature growth. mRNA profiles of mid-log phase WT(G), ΔVpacspA, ΔVpacspD and ΔVpacspAD at 10 °C were generated by deep sequencing using Illumina HiSeq 2500
Project description:The lysine acetylation of proteins is a major post-translational modification that plays an important regulatory role in almost every aspect of cells, both eukaryotes and prokaryotes. Vibrio parahaemolyticus, a model marine bacterium, is a worldwide cause of bacterial seafood-borne illness. Here, we conducted the first lysine acetylome in the bacterium through combination of highly sensitive immune-affinity purification and high-resolution LC-MS/MS. Overall, we identified 1413 lysine acetylation sites in 656 proteins, which account for 13.6% of the total proteins in the cells and is the highest ratio of acetyl proteins that has so far been identified in bacteria. The bioinformatics analysis of the acetylome showed that the acetylated proteins are involved in a wide range of cellular functions and exhibit diverse subcellular localizations. More specifically, proteins related to protein biosynthesis and carbon metabolism are the preferential targets of lysine acetylation. Moreover, two types of acetylation motifs, a lysine or arginine at the +4/+5 position and a tyrosine, histidine, or phenylalanine at the +1/+2 position, were revealed from the analysis of the acetylome. Additionally, the protein interaction network analysis demonstrates that a wide range of interactions are modulated by protein acetylation. This study provides a significant beginning for the in-depth exploration of the physiological role of lysine acetylation in V. parahaemolyticus.
Project description:AMPylation is a post-translational modification utilized by human and bacterial cells to modulate the activity and function of specific proteins. Major AMPylators such as human FICD and bacterial VopS have been studied extensively for their substrate and target scope in vitro. Recently, an AMP pronucleotide probe also facilitated the in situ analysis of AMPylation in living cells. Based on this technology we here introduce a novel UMP pronucleotide probe and utilize it in the profiling of uninfected and Vibrio parahaemolyticus infected human cells. Mass spectrometric analysis of labeled protein targets reveals an unexpected promiscuity of human nucleotide transferases with an almost identical target set of AMP- and UMPylated proteins. Vice versa, studies in cells infected by V. parahaemolyticus and its effector VopS revealed solely AMPylation of host enzymes highlighting a so far unknown specificity of this transferase for ATP. Taken together, pronucleotide probes provide an unprecedented insight into the in situ activity profile of crucial nucleotide transferases which can largely differ compared to their in vitro activity.
Project description:Here we probe the global response to calcium in the marine bacterium and pathogen Vibrio parahaemolyticus by using transcriptome, reporter and phenotypic analyses. Swarming gene expression and motility were enhanced by calcium. Calcium also stimulated expression and function of one of the organismM-bM-^@M-^Ys two type three secretion systems (T3SS1 but not the T3SS2). Although low calcium is an inducing signal for the T3SS of many organisms, calcium stimulation of T3SS has not been reported before. EGTA was also a stimulus for T3SS1 expression and activity; however this appeared to be the consequence of iron rather than calcium chelation. LafK, a key regulator of swarming genes, was found necessary for calcium induction of T3SS1 gene transcription and cytotoxicity. Regulation of swarming and T3SS1 were additionally linked by a negative feedback loop propagated by ExsA. Overexpression of exsA was used to probe the extent of the T3SS1 regulon and verify its coincident induction by calcium and EGTA. The calcium transcriptome analysis revealed a calcium-repressed LysR-type transcriptional regulator; CalR was shown to repress swarming and T3SS1 gene expression. Thus in V. parahaemolyticus, calcium influences gene expression and behavior and seems a signal pertinent for surface colonization and virulence. The gene expression profiles of Vibrio parahaemolyticus cells grown on rich medium or medium supplemented with CaCl2 or EGTA were compared using Affymetrix custom microarrays.
Project description:Vibrio parahaemolyticus is a Gram-negative marine bacterium. Strain RIMD 2210633, the wild type strain of the organism, causes acute gastroenteritis in humans. Human intestinal factor bile often affects the global gene regulation in some species of enteropathogenic bacteria. To determine the genes in V. parahaemolyticus that respond to bile, we investigated the differences in the transcriptomes of the wild type strain and the vtrA-null strain grown in Luria-Bertani medium cultivated with or without 0.04% crude bile. The vtrA gene encodes the previously identified T3SS2 regulator. Our goal is to demonstrate bile regulon controlled by VtrA in V. parahaemolyticus.
Project description:Vibrio parahaemolyticus is a Gram-negative marine bacterium. A limited population of the organisms causes acute gastroenteritis in humans. Almost all of the clinical V. parahaemolyticus isolates exhibit a beta-type hemolysis on Wagatsuma agar, known as the Kanagawa phenomenon (KP). KP is induced by the thermostable direct hemolysin (TDH) produced by the organism, and has been considered a crucial marker to distinguish pathogenic strains from non-pathogenic ones. Since 1996, so-called âpandemic clonesâ, the majority of which belong to serotype O3:K6, have caused worldwide outbreaks of gastroenteritis. In this study, we used a DNA microarray constructed based on the genome sequence of a pandemic V. parahaemolyticus strain RIMD2210633 to examin the genomic composition of 22 strains of V. parahaemolyticus, including both pathogenic (pandemic as well as non-pandemic) and non-pathogenic strains. Over 85% of the RIMD2210633 genes were conserved in all the strains tested. Many of variably present genes formed gene clusters on the genome of RIMD2210633 and were probably acquired through lateral gene transfer. At least 70 genes over 10 loci were specifically present in the pandemic strains when compared with any of the non-pandemic strains, suggesting that the difference between pandemic and non-pandemic strains is not due to a simple genetic event. Only the genes in the 80-kb pathogenicity island (Vp-PAI) on chromosome II, including two tdh genes and a set of genes for the Type III secretion system, were detected only in the KP-positive pathogenic strains. These results strongly suggest that acquisition of this Vp-PAI was crucial for the emergence of V. parahaemolyticus strains that are pathogenic for humans. Keywords: comparative genomic hybridization, CGH Total 66 test samples were analyzed. Genomic DNA from each test strain and a reference strain (RIMD2210633) were labeled with Cy3 and Cy5, respectively, and were cohybridized on a single array. Labeling and hybridization were performed three times independently.