|
|
||||||||

Department of Molecular Biology, Umeå University, S-901 87 Umeå, Sweden
Correspondence
Debra Milton
Debra.Milton{at}molbiol.umu.se
Vibrio anguillarum, a fish pathogen, produces a 38 kDa major outer-membrane porin, which may be involved in environmental adaptation. The gene encoding the 38 kDa porin was cloned and deleted. The deduced protein sequence was 75 % identical to that of the major outer-membrane protein (OMP), OmpU, from Vibrio cholerae. LacZ expression from an ompU : : lacZ transcriptional gene fusion was increased 1·5-fold in the presence of bile salts and was decreased 50- to 100-fold in a toxR mutant compared to that in the wild-type, showing that ompU expression is positively regulated by ToxR and induced by bile salts. Similar to a toxR mutant, an ompU mutant showed a slight decrease in motility, an increased sensitivity to bile salts and a thicker biofilm with better surface area coverage compared to that of the wild-type. When ompU was expressed under a ToxR-independent promoter in the toxR mutant, the phenotypes for bile resistance and biofilm formation, but not motility were complemented to that of the wild-type. In rainbow trout, the ompU mutant showed wild-type virulence via immersion into infected seawater and intraperitoneal injection. The ompU mutant produced two colony morphologies: opaque, which did not grow at 0·2 % bile, and translucent, which grew at 2 % bile. The translucent ompU mutant strain produced a second major OMP that was induced by bile. All ompU mutants showed variations in the amount and length of smooth LPS. In V. anguillarum, OmpU is not required for virulence, possibly due to a second OMP also critical for resistance to bile; however, outside of the fish host, OmpU limits the progression of biofilm formation.
The GenBank accession number for the sequence reported in this paper is AY157299.
Present address: The Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario, Canada N6A 4V2.
This article has been cited by other articles:
![]() |
Z. Yang, Q. Liu, Q. Wang, and Y. Zhang Novel Bacterial Surface Display Systems Based on Outer Membrane Anchoring Elements from the Marine Bacterium Vibrio anguillarum Appl. Envir. Microbiol., July 15, 2008; 74(14): 4359 - 4365. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Stelzer, S. Egan, M. R. Larsen, D. H. Bartlett, and S. Kjelleberg Unravelling the role of the ToxR-like transcriptional regulator WmpR in the marine antifouling bacterium Pseudoalteromonas tunicata. Microbiology, May 1, 2006; 152(Pt 5): 1385 - 1394. [Abstract] [Full Text] [PDF] |
||||
![]() |
D.-K. Park, K.-E. Lee, C.-H. Baek, I. H. Kim, J.-H. Kwon, W. K. Lee, K.-H. Lee, B.-S. Kim, S.-H. Choi, and K.-S. Kim Cyclo(Phe-Pro) Modulates the Expression of ompU in Vibrio spp. J. Bacteriol., March 15, 2006; 188(6): 2214 - 2221. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. R. Mey, S. A. Craig, and S. M. Payne Characterization of Vibrio cholerae RyhB: the RyhB Regulon and Role of ryhB in Biofilm Formation Infect. Immun., September 1, 2005; 73(9): 5706 - 5719. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. J. Welch and J. H. Crosa Novel Role of the Lipopolysaccharide O1 Side Chain in Ferric Siderophore Transport and Virulence of Vibrio anguillarum Infect. Immun., September 1, 2005; 73(9): 5864 - 5872. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |