This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Brown, R. N.
Right arrow Articles by Gulig, P. A.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Brown, R. N.
Right arrow Articles by Gulig, P. A.

 Previous Article  |  Next Article 

Infection and Immunity, September 2009, p. 3768-3781, Vol. 77, No. 9
0019-9567/09/$08.00+0     doi:10.1128/IAI.00205-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Roles of RseB, {sigma}E, and DegP in Virulence and Phase Variation of Colony Morphotype of Vibrio vulnificus{triangledown} ,{dagger}

Roslyn N. Brown{ddagger} and Paul A. Gulig*

Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, P.O. Box 100266, Gainesville, Florida 32610-0266

Received 23 February 2009/ Returned for modification 1 June 2009/ Accepted 18 June 2009

Vibrio vulnificus is an estuarine bacterium capable of causing serious and often fatal wound infections and primary septicemia. We used alkaline phosphatase insertion mutagenesis to identify genes necessary for the virulence of this pathogen. One mutant had an in-frame fusion of 'phoA to the gene encoding RseB, a periplasmic negative regulator of the alternative sigma factor {sigma}E. {sigma}E controls an extensive regulon involved in responding to cell envelope stresses. Colonies of the rseB mutant were less opaque than wild-type colonies and underwent phase variation between translucent and opaque morphologies. rseB mutants were attenuated for virulence in subcutaneously inoculated iron-dextran-treated mice. To obtain insight into the role of rseB and the extracytoplasmic stress response in V. vulnificus, mutants with defined mutations in rseB and two important members of the extracytoplasmic stress regulon, rpoE and degP, were constructed for analysis of virulence, colony morphology, and stress-associated phenotypes. Deletion of rseB caused reversible phase variation in the colony morphotype that was associated with extracellular polysaccharides. Translucent and transparent morphotype strains were attenuated for virulence. rpoE and degP deletion mutants were sensitive to membrane-perturbing agents and heat but were not significantly attenuated for V. vulnificus virulence in mice. These results reveal complex relationships between regulation of the extracytoplasmic stress response, exopolysaccharides, and the virulence of V. vulnificus.

* Corresponding author. Mailing address: Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, P.O. Box 100266, Gainesville, FL 32610-0266. Phone: (352) 392-0050. Fax: (352) 273-8905. E-mail: gulig{at}ufl.edu

{triangledown} Published ahead of print on 29 June 2009.

{dagger} Supplemental material for this article may be found at http://iai.asm.org/.

Editor: V. J. DiRita

{ddagger} Present address: Biological Separations and Mass Spectrometry, Pacific Northwest National Laboratory, Richland, WA 99352.

Infection and Immunity, September 2009, p. 3768-3781, Vol. 77, No. 9
0019-9567/09/$08.00+0     doi:10.1128/IAI.00205-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»