Project description:Investigation of whole genome gene expression level changes in a Vibrio cholerae O395N1 delta-nqrA-F mutant, compared to the wild-type strain. Total RNA recovered from wild-type cultures of VIbrio cholerae O395N1 and its nqrA-F mutant strain. Each chip measures the expression level of 3,835 genes from Vibrio cholerae O1 biovar eltor str. N16961 with twenty average probes/gene, with five-fold technical redundancy.
Project description:These experiments were performed to show serogroup conversion in Vibrio cholerae from O1 to O139 in a mixed communities / biofilms. For this purpose, V. cholerae O1 El Tor A1552 and VCO139-Kan strain (a MO10 derivative; O139 serogroup) were grown on crab shell fragments to induce natural competence for transformation. Transformants were selected on LB+Kan+Rif plates. O139 positive transformants have undergone a full exchange of the O1 region by the O139 region. This implies an exchange of an at least 32 kb spanning O1 genomic region by more than 42 kb of the O139 region. The transformation experiment was done at least five independent times; data from four experiments are shown; per experiment one to three clones were analysed by CGH with two experimental replicates each. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. Keywords: all_pairs, array CGH
Project description:These experiments were performed to show serogroup conversion in Vibrio cholerae from O1 to O139 in a mixed communities / biofilms. For this purpose, V. cholerae O1 El Tor A1552 and VCO139-Kan strain (a MO10 derivative; O139 serogroup) were grown on crab shell fragments to induce natural competence for transformation. Transformants were selected on LB+Kan+Rif plates. O139 positive transformants have undergone a full exchange of the O1 region by the O139 region. This implies an exchange of an at least 32 kb spanning O1 genomic region by more than 42 kb of the O139 region. The transformation experiment was done at least five independent times; data from four experiments are shown; per experiment one to three clones were analysed by CGH with two experimental replicates each.
Project description:These experiments were performed to show a serogroup conversion in Vibrio cholerae from O1 to O139. For this purpose, V. cholerae O1 WT = A1552 was grown on crab shell fragments to induce natural competence for transformation. Purified DNA (2 ug each) from strain VC73-orf6/7-Kan-A was added after 24h and the cells grown further for 24h. The VC73-orf6/7-Kan-A strain is a ATCC25873 derivative (both O37 serogroup) which harbors a Kanamycin cassette in the O37 region (as part of the operon between orf6 and orf7 w/o own promotor) for better selection. Transformants were selected on LB+Kan plates. Three clones were selected from each experiment and analyzed by microarray hybridization (BioPrime. Array CGH Genomic Labeling from Invitrogen). Two microarray replicates were done per clone. Comparison of A1552 versus VC73-orf6/7-Kan-A is shown as control. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. Keywords: genotyping_design
Project description:These experiments were performed to show a serogroup conversion in Vibrio cholerae from O1 to O139. For this purpose, V. cholerae O1 WT = A1552 was grown on crab shell fragments to induce natural competence for transformation. Purified DNA (2 ug each) from strain VC73-orf6/7-Kan-A was added after 24h and the cells grown further for 24h. The VC73-orf6/7-Kan-A strain is a ATCC25873 derivative (both O37 serogroup) which harbors a Kanamycin cassette in the O37 region (as part of the operon between orf6 and orf7 w/o own promotor) for better selection. Transformants were selected on LB+Kan plates. Three clones were selected from each experiment and analyzed by microarray hybridization (BioPrime. Array CGH Genomic Labeling from Invitrogen). Two microarray replicates were done per clone. Comparison of A1552 versus VC73-orf6/7-Kan-A is shown as control.
Project description:These experiment were performed to show a serogroup conversion in Vibrio cholerae from O1 to O139. For this purpose, V. cholerae O1 WT = A1552 was grown on crab shell fragments to induce natural competence for transformation. Purified DNA (2 ug each) from strain VCO139-Kan was added after 24h and the cells grwon further for 24h. The VCO139-Kan strain is a MO10 derivative (both O139 serogroup) which harbors a Kanamycin cassette in the O139 region (as part of the operon between wbfA and wbfB w/o own promotor) for better selection. Transformants were selected on LB+Kan plates. Two groups of transformants were gained: Group I had a full exchange of the O1 region by the O139 region (clones serogroup-converted: SGC#1-3); the crossovers for the homologous recombination event had occurred within or upstream of the gmhD gene and in most instances within or downstream of the homolog gene of VC0271. This implies an exchange of an at least 33 kb spanning O1 genomic region by more than 42 kb of the O139 region. Group II had only half of the O139 region transfered and therefore half of the O1 region kept (clones HSGC#4-6). We analyzed their genotype and found that all of them had undergone a homologous recombination event with one crossover in or upstream of the gmhD gene and the second one inside the VC0254 and IS1358 gene. The transformation experiment was done three independent times (I - III). Three clones from group I and group II were selected from each experiment and analyzed by microarray hybridization (BioPrime. Array CGH Genomic Labeling from Invitrogen). Two microarray replicates were done per clone.
Project description:DNA pulldown assays were performed as previously described 43. Briefly, the biotin-labeled DNA fragment containing the promoter region of chsR was amplified from Vibrio cholerae O1 El Tor strain E12382 genomic DNA. The biotinylated bait DNA was bound to streptavidin-coated Dynabeads (catalog no. 11205D; Invitrogen), followed by incubation with crude extracts obtained from Vibrio cholerae O1 El Tor WT cells. After washing extensively with the nonspecific competitor poly (dI-dC) at a low salt concentration, bound proteins were released by elution buffer containing 500 mM NaCl. The eluted proteins were separated by SDS‒PAGE and stained with Coomassie brilliant blue. Proteins were excised from the gel and analyzed by matrix-assisted laser desorption ionization–time-of-flight tandem mass spectrometry (MALDI-TOF MS/MS) analysis after tryptic digestion. Sequence and peptide fingerprint data were analyzed using the NCBI database.
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:These experiments were performed to show a serogroup conversion of Vibrio cholerae from O1 to O139. For this purpose, V. cholerae O1 El Tor (A1552) was grown on crab shell fragments to induce natural competence for transformation. Purified DNA (4 ug each) from strain MO10, an O139 serogroup strain, was added after 24h and the cells were further grown for 24h. After detachment from the crab shell fragments, bacteria were poured into soft-agar and overlaid onto LB plates. Mukerjees El Tor phage V (a gift of Dr. M.S. Islam) was dropped onto the surface of the bacteria containing soft-agar. The plaques formed by killing non-transformed A1552 cells possessed resistant clones which were picked and further selected for opaque morphotype and agglutination by O139-specific antiserum. Four clones were selected from each independent experiment and analyzed by microarray hybridization (BioPrime. Array CGH Genomic Labeling from Invitrogen). Two microarray replicates were done per clone. Strain Names: AIIIpO139#1 / AIIIpO139#3 / AIIIpO139#4 / AIIIpO139#5 are four clones analyzed after the second experiment; AIVpO139#2 / AIVpO139#4 / AIVpO139#5 / AIVpO139#8 are four clones analyzed after the fourth independent experiment. Two MA replicates for each clone were done.
Project description:Vibrio cholerae is a Gram negative, motile, facultative anaerobic bacterium, and the causative agent of cholera, a severe diarrhoeal disease, which untreated can rapidly lead to dehydration, hypotensive shock, and death. Cholera is a significant human disease that is estimated to affect 3-5 million people each year. The mechanism by which V. cholerae regulates virulence gene expression in vivo is unknown, but a number of studies have suggested that low molecular weight signally molecules may be important in modulating gene expression. cFP is a low molecular weight cyclic dipeptide produced by multiple Vibrio species. Evidence previously generated in our laboratory showed that cFP inhibited the production of the virulence factors cholera toxin (CT) and the toxin coregulated pilus (TCP) in O1 El Tor V. cholerae strain N16961 during growth under virulence gene inducing conditions. cFP inhibition of CT and TCP production correlated with reduced transcription of several regulators that belong to the ToxR regulon. To identify additional cFP-responsive genes we performed microarray experiments with the O1 El Tor V. cholerae strain N16961. In these experiments N16961 was grown under virulence gene inducing conditions in the presence and absence of cFP before RNA was extracted and hybridized to microarrays. The results showed that cFP positively affected the expression of the LysR-family regulatory protein LeuO. This finding suggests the possibility that LeuO may be mediating cFP-dependent regulation of gene expression in response to environmental cFP. V. cholerae N16961 was grown under AKI growth condition in the presence or absence of 1 mM cFP for 2.5 or 3 hours when total RNA was extracted, differentially labelled and hybridized to microarrays. Four independent experiments were performed.