This Article Full Text (PDF) Other Versions of this Article: JB.00583-07v1 189/23/8484    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sikora, A. E. Articles by Sandkvist, M. Search for Related Content PubMed PubMed Citation Articles by Sikora, A. E. Articles by Sandkvist, M.

 Previous Article  |  Next Article 

J. Bacteriol. doi:10.1128/JB.00583-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Compromised outer membrane integrity in Vibrio cholerae type II secretion mutants

Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI

^* To whom correspondence should be addressed. Email: mariasan{at}umich.edu.

	Abstract

The type II secretion (T2S) system of Vibrio cholerae is a multiprotein complex that spans the cell envelope and secretes proteins important for pathogenesis as well as survival in different environments. Here we report that, in addition to loss of extracellular secretion, removal or inhibition of expression of the T2S genes, epsC-N, results in growth defects and a broad range of alterations in the outer membrane that interfere with its barrier function. Specifically, the sensitivity to membrane perturbing agents such as bile salts and the antimicrobial peptide polymyxin B is increased and periplasmic constituents leak out into the culture medium. As a consequence, the o'^E stress response is induced. Furthermore, due to the defects caused by inactivation of the T2S system the eps deletion mutant of V. cholerae strain N16961 is incapable of surviving the passage through the infant mouse gastro-intestinal tract. The growth defect and leaky outer membrane phenotypes are suppressed when the culture medium is supplemented with 5% glucose or sucrose, although the eps mutants remain sensitive to membrane damaging agents. This suggests that the sugars do not restore the integrity of the outer membrane in the eps mutant strains per se, but may provide osmoprotective functions.