Project description:Vibrio alginolyticus is a Gram-negative marine bacterium. A limited population of the organisms causes acute gastroenteritis in humans. In this study, Vibrio alginolyticus wild type strain EPGS is compared with the mutants of Ser-Thr kinase PpkA and phosphatase PppA, after cultured for 7h, in Luria-Bertani containing medium 3 % NaCl at 30 C. Our goal is to determine the ppkA and pppA regulon.
Project description:Vibrio alginolyticus is a Gram-negative marine bacterium. A limited population of the organisms causes acute gastroenteritis in humans. In this study, Vibrio alginolyticus wild type strain EPGS is compared with the mutants of Ser-Thr kinase PpkA and phosphatase PppA, after cultured for 7h, in Luria-Bertani containing medium 3 % NaCl at 30 C. Our goal is to determine the ppkA and pppA regulon. Three wild type and five mutant Vibrio alginolyticus samples were compared.
Project description:In recent years, due to the influence of climate change and rising sea temperature, the incidence of Vibrio alginolyticus infections is increasing, and becoming the second most common Vibrio species reported in human illness. Therefore, better understanding of the pathogenic mechanism of V. alginolyticus infection is urgently needed. Vvrr1 (Vibrio virulence regulatory RNA 1) is a new found ncRNA predicted to be closely related to the adhesion ability of V. alginolyticus through the previous RNA-seq. In this study, the target genes of Vvrr1 were fully screened and verified by constructing Vvrr1 over-expressed strains and proteome sequencing technology.
Project description:Vibrio cholerae is highly motile by the action of a single polar flagellum. The loss of motility reduces the infectivity of V. cholerae, demonstrating that motility is an important virulence factor. FlrC is the sigma-54-dependent positive regulator of flagellar genes. Recently, the genes VC2206 (flgP) and VC2207 (flgO) were identified as being regulated by FlrC by microarray analysis of an flrC mutant. FlgP is reported to be an outer membrane lipoprotein required for motility that functions as a colonization factor. The study reported here focuses on the characterization of flgO, the first gene in the flgOP operon. We show FlgO/P are important for motility, as these mutants have reduced motility phenotypes. The flgO/P mutant populations display fewer motile cells as well as reduced numbers of flagellated cells. The flagella produced by the flgO/P mutant strains are shorter in length than the WT flagella, which can be restored by inhibiting rotation of the flagellum. FlgO is an outer membrane protein that localizes throughout the membrane and not at the flagellar pole. Although FlgO/P do not specifically localize to the flagellum, they are required for flagellar stability. Due to the nature of these motility defects, we established that the flagellum is not sufficient for adherence, rather, motility is the essential factor required for attachment and thus colonization by V. cholerae O1 of the classical biotype. This study reveals a novel mechanism for which the OMPs FlgO and FlgP function in motility to mediate flagellar stability and influence attachment and colonization. Vibrio cholerae O395 vs. rpoN mutant
Project description:Vibrio cholerae is highly motile by the action of a single polar flagellum. The loss of motility reduces the infectivity of V. cholerae, demonstrating that motility is an important virulence factor. FlrC is the sigma-54-dependent positive regulator of flagellar genes. Recently, the genes VC2206 (flgP) and VC2207 (flgO) were identified as being regulated by FlrC by microarray analysis of an flrC mutant. FlgP is reported to be an outer membrane lipoprotein required for motility that functions as a colonization factor. The study reported here focuses on the characterization of flgO, the first gene in the flgOP operon. We show FlgO/P are important for motility, as these mutants have reduced motility phenotypes. The flgO/P mutant populations display fewer motile cells as well as reduced numbers of flagellated cells. The flagella produced by the flgO/P mutant strains are shorter in length than the WT flagella, which can be restored by inhibiting rotation of the flagellum. FlgO is an outer membrane protein that localizes throughout the membrane and not at the flagellar pole. Although FlgO/P do not specifically localize to the flagellum, they are required for flagellar stability. Due to the nature of these motility defects, we established that the flagellum is not sufficient for adherence, rather, motility is the essential factor required for attachment and thus colonization by V. cholerae O1 of the classical biotype. This study reveals a novel mechanism for which the OMPs FlgO and FlgP function in motility to mediate flagellar stability and influence attachment and colonization.
Project description:RNA-seq analysis demonstrated that VqsA (18672) controls ~275 genes' expression in V. alginolyticus. Collectively, our data established that VqsA plays essential roles in QS regulation and may facilitate the illumination of the mechanisms bacterial cells sense environmental signals and integrate them into coordinated QS responses.
Project description:Vibrio vulnificus (V. vulnificus) is an opportunistic human pathogen known for causing various illnesses such as gastroenteritis, skin and muscle necrosis, septic shock, and sepsis. This halophilic estuarine bacterium's growth and infection process involves adaptation to both the natural briny environments and the host. OmpR, a response regulator in the EnvZ/OmpR two-component regulatory system (TCS), is crucial for environmental adaptation and pathogenicity. This study focused on investigating the impact of OmpR in V. vulnificus by creating an ompR knockout strain (ΔompR). The ΔompR strain exhibited reduced tolerance to alkaline stress, shorter flagella, and decreased virulence in epithelial cell and mouse models compared to the wild-type (WT) V. vulnificus. RNAseq analysis revealed the downregulation of genes involved in metabolism, flagellum-dependent motility, and transcription factors in the ΔompR strain. OmpR was found to repress the expression of aphB in alkaline conditions, impacting the acid resistance system CadBA, while also positively regulating the transcription of various flagellar genes. These findings suggest that OmpR acts as a global regulator, orchestrating the expression of multiple genes in response to different environments and during host invasion.