Many selective enrichment methods for the isolation of Yersinia enterocolitica from foods have been described. However, no single isolation procedure has been described for the recovery and identification of various plasmid-bearing serotypes. A single improved procedure for selective enrichment, isolation, identification, and maintenance of plasmid-bearing virulent serotypes of Y. enterocolitic...

Shigella species and enteroinvasive strains of Escherichia coli cause disease by invasion of the colonic epithelium, and this invasive phenotype is mediated by genes carried on 180- to 240-kb plasmids. In addition, at least eight loci on the Shigella chromosome are necessary for full expression of virulence. The products of these genes can be classified as (i) virulence determinants that direct...

The bitopic membrane protein VirB10 of the Agrobacterium VirB/VirD4 type IV secretion system (T4SS) undergoes a structural transition in response to sensing of ATP binding or hydrolysis by the channel ATPases VirD4 and VirB11. This transition, detectable as a change in protease susceptibility, is required for DNA substrate passage through the translocation channel. Here, we present evidence tha...

Several regulators within the AraC family control the expression of genes known or thought to be required for virulence of bacterial pathogens. One of these, Rns, activates transcription from an unprecedented variety of binding-site locations. Although nearly all prokaryotic activators bind within a small region upstream and adjacent to the promoter that they regulate, Rns does not bind within ...

Yersinia enterocolitica is a foodborne pathogen that causes illness in humans and animals. The biotype 4/O:3 has been commonly associated with yersiniosis and is characterized by the presence of chromosomal and extra-chromosomal virulence genes. Molecular typing methods have been successfully used to characterize Y. enterocolitica genetic heterogeneity and to study the epidemiology of the bacte...

The temperature-dependent regulation of Shigella virulence genes is believed to be accomplished at the transcriptional stage by the regulators VirF and InvE. Several lines of evidence herein described indicate that post-transcriptional regulation of InvE expression plays a key role in the temperature-dependent regulation of virulence gene expression: (i) a considerable amount of invE mRNA conti...

Yersinia enterocolitica comprises six biotypes 1A, 1B, 2, 3, 4, and 5. The virulence of the strains belonging to biotypes 1B and 2-5 depends on the presence of both chromosomal and plasmid-borne genes. Strains belonging to biotype 1A do not carry the virulence plasmid pYV. However, they carry other virulence genes, such as ystB and hreP. The aim of this study was to investigate the distribution...