Project description:The genome of Vibrio cholerae encodes two higBA toxin-antitoxin (TA) modules that are activated by amino-acid starvation. Here, the TA complex of the second module, higBA2, as well as the C-terminal domain of the corresponding HigA2 antitoxin, have been purified and crystallized. The HigBA2 complex crystallized in two crystal forms. Crystals of form I belonged to space group P2(1)2(1)2, with unit-cell parameters a = 129.0, b = 119.8, c = 33.4?Å, and diffracted to 3.0?Å resolution. The asymmetric unit is likely to contain a single complex consisting of two toxin monomers and one antitoxin dimer. The second crystal form crystallized in space group P3(2)21, with unit-cell parameters a = 134.5, c = 55.4?Å. These crystals diffracted to 2.2?Å resolution and probably contain a complex with a different stoichiometry. Crystals of the C-terminal domain of HigA2 belonged to space group C2, with unit-cell parameters a = 115.4, b = 61.2, c = 73.8?Å, ? = 106.7°, and diffracted to 1.8?Å resolution.
Project description:Secretion of cholera toxin and other virulence factors from Vibrio cholerae is mediated by the type II secretion (T2S) apparatus, a multiprotein complex composed of both inner and outer membrane proteins. To better understand the mechanism by which the T2S complex coordinates translocation of its substrates, we are examining the protein-protein interactions of its components, encoded by the extracellular protein secretion (eps) genes. In this study, we took a cell biological approach, observing the dynamics of fluorescently tagged EpsC and EpsM proteins in vivo. We report that the level and context of fluorescent protein fusion expression can have a bold effect on subcellular location and that chromosomal, intraoperon expression conditions are optimal for determining the intracellular locations of fusion proteins. Fluorescently tagged, chromosomally expressed EpsC and EpsM form discrete foci along the lengths of the cells, different from the polar localization for green fluorescent protein (GFP)-EpsM previously described, as the fusions are balanced with all their interacting partner proteins within the T2S complex. Additionally, we observed that fluorescent foci in both chromosomal GFP-EpsC- and GFP-EpsM-expressing strains disperse upon deletion of epsD, suggesting that EpsD is critical to the localization of EpsC and EpsM and perhaps their assembly into the T2S complex.
Project description:This study is an analysis of changes in gene expression during stringent response in Vibrio cholerae. V. cholerae cells in mid-log were treated with serine hydroxamate and gene expression was compared to untreated cells. Keywords: Stress response, stringent response
Project description:Environmental isolates of Vibrio cholerae from California coastal water compared to reference strain N16961. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. Keywords: genotyping_design; array CGH
Project description:Question Addressed: Does gene expression in V. cholerae change when samples are frozen at -80 degrees? An in vitro grown culture of O1 Inaba ICDDR,B (strain DSM-V999 described in Nature. 2002 Jun 6;417(6889):642-5) that had been grown to exponential phase (OD600 + 0.2) was placed in a 15 ml conical and then placed in a -80 degree freezer. A portion of the starting culture was harvested prior to freezing to serve as the control/reference for downstream hybridizations. RNA was recovered from the non-frozen sample as well as by prepping material directly from frozen samples. Labeling reactions were performed in quadruplicate for each sample. A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments.
Project description:Question Addressed: What is the level of expression of genes in Vibrio cholerae recovered from various conditions. These conditions include samples recovered directly from patients (O139 from stool samples from ICDDR,B and N16961 from stool samples from a vaccine trial held in Cincinnati) as well as standard logarithmic and stationary phase grown bacteria. Labeling reactions were performed in duplicate for each stool derived and in quadruplicate for each in vitro grown strain. A common reference was used for each slide, it was composed of RNA from the exponentially growing 92A1552 V. cholerae strain
Project description:We resolved the relationships between 2 pandemic clones of Vibrio cholerae. Using 26 housekeeping genes, we showed that the US Gulf clone, the Australian clone, and 3 El Tor strains isolated before the seventh pandemic were related to the seventh pandemic clone. The sixth pandemic clone was well separated from them.