Novel Colicin F-Y of Yersinia frederiksenii Inhibits Pathogenic Yersinia Strains via YiuR-Mediated Reception, TonB Import, and Cell Membrane Pore Formation

A novel colicin type, designated colicin F-Y, was found to be encoded and produced by the strain Yersinia frederiksenii Y27601. Colicin F-Y was active against both pathogenic and nonpathogenic strains of the genus Yersinia. Plasmid YF27601 (5,574 bp) of Y. frederiksenii Y27601 was completely sequenced. The colicin F-Y activity gene (cfyA) and the colicin F-Y immunity gene (cfyI) were identified. The deduced amino acid sequence of colicin F-Y was very similar in its C-terminal pore-forming domain to colicin Ib (69% identity in the last 178 amino acid residues), indicating pore forming as its lethal mode of action. Transposon mutagenesis of the colicin F-Y-susceptible strain Yersinia kristensenii Y276 revealed the yiuR gene (ykris001_4440), which encodes the YiuR outer membrane protein with unknown function, as the colicin F-Y receptor molecule. Introduction of the yiuR gene into the colicin F-Y-resistant strain Y. kristensenii Y104 restored its susceptibility to colicin F-Y. In contrast, the colicin F-Y-resistant strain Escherichia coli TOP10F' acquired susceptibility to colicin F-Y only when both the yiuR and tonB genes from Y. kristensenii Y276 were introduced. Similarities between colicins F-Y and Ib, similarities between the Cir and YiuR receptors, and the detected partial cross-immunity of colicin F-Y and colicin Ib producers suggest a common evolutionary origin of the colicin F-Y-YiuR and colicin Ib-Cir systems

Shotgun sequencing of Yersinia enterocolitica strain W22703 (biotype 2, serotype O:9): genomic evidence for oscillation between invertebrates and mammals

<p>Abstract</p> <p>Background</p> <p><it>Yersinia enterocolitica </it>strains responsible for mild gastroenteritis in humans are very diverse with respect to their metabolic and virulence properties. Strain W22703 (biotype 2, serotype O:9) was recently identified to possess nematocidal and insecticidal activity. To better understand the relationship between pathogenicity towards insects and humans, we compared the W22703 genome with that of the highly pathogenic strain 8081 (biotype1B; serotype O:8), the only <it>Y. enterocolitica </it>strain sequenced so far.</p> <p>Results</p> <p>We used whole-genome shotgun data to assemble, annotate and analyse the sequence of strain W22703. Numerous factors assumed to contribute to enteric survival and pathogenesis, among them osmoregulated periplasmic glucan, hydrogenases, cobalamin-dependent pathways, iron uptake systems and the <it>Yersinia </it>genome island 1 (YGI-1) involved in tight adherence were identified to be common to the 8081 and W22703 genomes. However, sets of ~550 genes revealed to be specific for each of them in comparison to the other strain. The plasticity zone (PZ) of 142 kb in the W22703 genome carries an ancient flagellar cluster Flg-2 of ~40 kb, but it lacks the pathogenicity island YAPI_Ye, the secretion system <it>ysa </it>and <it>yts1</it>, and other virulence determinants of the 8081 PZ. Its composition underlines the prominent variability of this genome region and demonstrates its contribution to the higher pathogenicity of biotype 1B strains with respect to W22703. A novel type three secretion system of mosaic structure was found in the genome of W22703 that is absent in the sequenced strains of the human pathogenic <it>Yersinia </it>species, but conserved in the genomes of the apathogenic species. We identified several regions of differences in W22703 that mainly code for transporters, regulators, metabolic pathways, and defence factors.</p> <p>Conclusion</p> <p>The W22703 sequence analysis revealed a genome composition distinct from other pathogenic <it>Yersinia enterocolitica </it>strains, thus contributing novel data to the <it>Y. enterocolitica </it>pan-genome. This study also sheds further light on the strategies of this pathogen to cope with its environments.</p