title: Putative type VI secretion systems of Vibrio parahaemolyticus contribute to adhesion to cultured cell monolayers.
abstract: Analysis of the genome sequence of Vibrio parahaemolyticus reveals two IcmF family genes in putative type VI secretion system (vpT6SS) clusters in chromosomes 1 (icmF1) and 2 (icmF2). The icmF1 gene is present in majority of clinical isolates (87.5 %), but has a low fraction (25.0 %) in environmental isolates. However, icmF2 is contained in all strains of both clinical and environmental sources. Deletion of either icmF1 or hcp1 significantly reduced bacterial adhesion to Caco-2 cells or HeLa monolayers. However, the ΔicmF2 and Δhcp2 mutants showed decreased adhesion only to HeLa monolayers. Western blot analysis showed that Hcp2 was present both in the supernatant and pellet samples in the wild-type strain, but only in the pellet of the ΔicmF2 mutant, indicating that Hcp2 is a translocon of T6SS2. Although vpT6SS1 might be functional in cellular adhesion, the putative translocon Hcp1 was not detectable. Quantitative PCR revealed 10-fold and 17-fold less transcripts of hcp1 and icmF1 mRNA than those of hcp2 and icmF2 accordingly. Thus, we postulate that the putative vpT6SS systems contribute to adhesion of V. parahaemolyticus to host cells.
authors.affiliation: Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Institute of Preventive Veterinary Medicine, Zhejiang University, 388 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yu
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Peipei
authors.initials: P
authors.lastname: Zhang
authors.forename: Beibei
authors.initials: B
authors.lastname: Wu
authors.forename: Binglin
authors.initials: B
authors.lastname: Zhu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Weihuan
authors.initials: W
authors.lastname: Fang
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018938:Caco-2 Cells; D002478:Cells, Cultured; D015964:Gene Expression Regulation, Bacterial; D006367:HeLa Cells; D006801:Humans; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors