Abstract |
Genes encoding cell-surface proteins regulated by SigB are stably expressed in Staphylococcus aureus small-colony variants (SCVs) isolated from cystic fibrosis (CF) patients. Our hypothesis is that CF-isolated SCVs are locked into a colonization state by sustaining the expression of adhesins such as fibronectin- binding proteins (FnBPs) throughout growth. Force spectroscopy was used to study the fibronectin-FnBPs interaction among strains varying for their SigB activity. The fibronectin-FnBPs interaction was described by a strength of 1000+/-400 pN (pulling rate of 2 microm s(-1)), an energetic barrier width of 0.6+/-0.1 A and an off-rate below 2 x 10(-4) s(-1). A CF-isolated SCV highly expressed fnbA throughout growth and showed a sustained capacity to bind fibronectin, whereas a prototypic strain showed a reduced frequency of fibronectin-binding during the stationary growth phase when its fnbA gene was down-regulated. Reduced expression of fnbA was observed in sigB mutants, which was associated with an overall decrease adhesion to fibronectin. These results suggest that the fibronectin-FnBPs interaction plays a role in the formation of a mechanically resistant adhesion of S. aureus to host tissues and supports the hypothesis that CF-isolated SCVs are locked into a colonization state as a result of a sustained SigB activity.
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Authors | Gabriel Mitchell, Charles-Antoine Lamontagne, Eric Brouillette, Gilles Grondin, Brian G Talbot, Michel Grandbois, François Malouin |
Journal | Molecular microbiology
(Mol Microbiol)
Vol. 70
Issue 6
Pg. 1540-55
(Dec 2008)
ISSN: 1365-2958 [Electronic] England |
PMID | 19007412
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Adhesins, Bacterial
- Bacterial Proteins
- Fibronectins
- SigB protein, Bacteria
- Sigma Factor
- fibronectin-binding proteins, bacterial
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Topics |
- Adhesins, Bacterial
(metabolism)
- Bacterial Adhesion
- Bacterial Proteins
(metabolism)
- Cystic Fibrosis
(metabolism, microbiology)
- Fibronectins
(metabolism)
- Host-Pathogen Interactions
- Humans
- Sigma Factor
(metabolism)
- Staphylococcus aureus
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