| vibrio cholerae hemagglutinin/protease inactivates ctxphi. | pathogenic strains of vibrio cholerae are lysogens of the filamentous phage ctxphi, which carries the genes for cholera toxin (ctxab). we found that the titers of infective ctxphi in culture supernatants of el tor ctxphi lysogens increased rapidly during exponential growth but dropped to undetectable levels late in stationary-phase growth. when ctxphi transducing particles were mixed with stationary-phase culture supernatants of el tor strains, ctxphi infectivity was destroyed. our data indicate ... | 1998 | 9712742 |
| mobilization of the vibrio pathogenicity island between vibrio cholerae isolates mediated by cp-t1 generalized transduction. | pathogenicity islands are large chromosomal regions encoding virulence genes that were acquired by horizontal gene transfer and are found in a wide range of pathogenic bacteria. in toxigenic vibrio cholerae isolates the receptor for the cholera toxin encoding filamentous phage ctxphi, the toxin-coregulated pilus, is part of the vibrio pathogenicity island (vpi). in this paper, we show that the vpi can be transferred between o1 serogroup strains, the predominant cause of epidemic cholera, via a g ... | 2002 | 12351223 |
| comparative genomic analyses of the vibrio pathogenicity island and cholera toxin prophage regions in nonepidemic serogroup strains of vibrio cholerae. | two major virulence factors are associated with epidemic strains (o1 and o139 serogroups) of vibrio cholerae: cholera toxin encoded by the ctxab genes and toxin-coregulated pilus encoded by the tcpa gene. the ctx genes reside in the genome of a filamentous phage (ctxphi), and the tcpa gene resides in a vibrio pathogenicity island (vpi) which has also been proposed to be a filamentous phage designated vpiphi. in order to determine the prevalence of horizontal transfer of vpi and ctxphi among none ... | 2003 | 12620865 |
| phage regulatory circuits and virulence gene expression. | in many pathogenic bacteria, genes that encode virulence factors are located in the genomes of prophages. clearly bacteriophages are important vectors for disseminating virulence genes, but, in addition, do phage regulatory circuits contribute to expression of these genes? phages of the lambda family that have genes encoding shiga toxin are found in certain pathogenic escherichia coli (known as shiga toxin producing e. coli) and the filamentous phage ctxphi, that carries genes encoding cholera t ... | 2005 | 15979389 |
| new wrinkles and folds in site-specific recombination. | the new work of reveals a new site-specific recombination strategy to establish lysogeny, in which a double-stranded recombination substrate is assembled from the folded single-stranded dna genome of the filamentous vibrio cholerae phage ctxphi. this strategy allows the phage to use the host's recombinases while at the same time preventing inappropriate excision of the prophage. | 2005 | 16109368 |
| binding efficiencies of carbohydrate ligands with different genotypes of cholera toxin b: molecular modeling, dynamics and docking simulation studies. | vibrio cholerae produces cholera toxin (ct) that consists of two subunits, a and b, and is encoded by a filamentous phage ctxf. the a subunit carries enzymatic activity that ribosylates adp, whereas the b subunit binds to monosialoganglioside (gm1) receptor in epithelial cells. molecular analysis of toxigenic v. cholerae strains indicated the presence of multiple ctxb genotypes. in this study, we employed a comparative modeling approach to define the structural features of all known variants of ... | 2011 | 21409571 |