JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
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
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sullivan, J. T.
Right arrow Articles by Ramakrishnan, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sullivan, J. T.
Right arrow Articles by Ramakrishnan, G.
Journal of Bacteriology, June 2006, p. 3785-3795, Vol. 188, No. 11
0021-9193/06/$08.00+0     doi:10.1128/JB.00027-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Characterization of the Siderophore of Francisella tularensis and Role of fslA in Siderophore Production{dagger}

Jonathan Tabb Sullivan,1 Erin Field Jeffery,2 John D. Shannon,3 and Girija Ramakrishnan1*

Departments of Internal Medicine,1 Chemistry,2 Microbiology, University of Virginia, Charlottesville, Virginia 229083

Received 9 January 2006/ Accepted 19 March 2006

We determined that LVS and Schu S4 strains of the human pathogen Francisella tularensis express a siderophore when grown under iron-limiting conditions. We purified this siderophore by conventional column chromatography and high-pressure liquid chromatography and used mass spectrometric analysis to demonstrate that it is structurally similar to the polycarboxylate siderophore rhizoferrin. The siderophore promoted the growth of LVS and Schu S4 strains in iron-limiting media. We identified a potential siderophore biosynthetic gene cluster encoded by fslABCD in the F. tularensis genome. The first gene in the cluster, fslA, encodes a member of the superfamily of nonribosomal peptide synthetase-independent siderophore synthetases (NIS synthetases) characterized by the aerobactin synthetases IucA and IucC. We determined that fslA is transcribed as part of an operon with downstream gene fslB and that the expression of the locus is induced by iron starvation. A targeted in-frame nonpolar deletion of fslA in LVS resulted in the loss of siderophore expression and in a reduced ability of F. tularensis to grow under conditions of iron limitation. Siderophore activity and the ability to grow under iron limitation could be regained by introducing the fslA+ gene on a complementing plasmid. Our results suggest that the fslA-dependent siderophore is important for survival of F. tularensis in an iron-deficient environment.

* Corresponding author. Mailing address: P.O. Box 801367, University of Virginia Health System, MR4 Bldg., Rm. 2126, Charlottesville, VA 22908-5621. Phone: (434) 982-0003. Fax: (434) 924-0075. E-mail: gr6q{at}virginia.edu.

{dagger} This paper is dedicated to the memory of the late Robert J. Kadner, who was a source of advice and encouragement through the progress of this investigation.

Journal of Bacteriology, June 2006, p. 3785-3795, Vol. 188, No. 11
0021-9193/06/$08.00+0     doi:10.1128/JB.00027-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 2006 by the American Society for Microbiology. All rights reserved.