σB Inhibits Poly-N-Acetylglucosamine Exopolysaccharide Synthesis and Biofilm Formation in Staphylococcus aureus
Staphylococcus aureus clinical strains are able to produce at least two distinct types of biofilm matrixes: biofilm matrixes made of the polysaccharide intercellular adhesin (PIA) or poly-N-acetylglucosamine (PNAG), whose synthesis is mediated by the icaADBC locus, and biofilm matrixes built of proteins (polysaccharide independent). σB is a conserved alternative sigma factor that regulates the expression of more than 100 genes in response to changes in environmental conditions. While numerous studies agree that σB is required for polysaccharide-independent biofilms, controversy persists over the role of σB in the regulation of PIA/PNAG-dependent biofilm development. Here, we show that genetically unrelated S. aureus σB-deficient strains produced stronger biofilms under both static and flow conditions and accumulated higher levels of PIA/PNAG exopolysaccharide than their corresponding wild-type strains. The increased accumulation of PIA/PNAG in the σB mutants correlated with a greater accumulation of the IcaC protein showed that it was not due to adjustments in icaADBC operon transcription and/or icaADBC mRNA stability. Overall, our results reveal that in the presence of active σB, the turnover of Ica proteins is accelerated, reducing the synthesis of PIA/PNAG exopolysaccharide and consequently the PIA/PNAG-dependent biofilm formation capacity.
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | artículo biblioteca |
| Language: | English |
| Published: |
American Society for Microbiology
2019-05-08
|
| Subjects: | Biofilms, PNAG, SigB, Staphylococcus aureus, Ica operon, |
| Online Access: | http://hdl.handle.net/10261/191825 http://dx.doi.org/10.13039/501100000780 http://dx.doi.org/10.13039/501100003329 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|