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CodY-mediated regulation of Streptococcus pyogenesexoproteins » Isaúde
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BMC microbiology [electronic resource]
2012-06-22 03:34:59

CodY-mediated regulation of Streptococcus pyogenesexoproteins

Descrição: Background:The production of Streptococcus pyogenes exoproteins, many of which contribute tovirulence, is regulated in response to nutrient availability. CodY is a transcriptional regulatorthat controls gene expression in response to amino acid availability. The purpose of this studywas to identify differences in the expression of streptococcal exoproteins associated withdeletion of the codY gene.Results:We compared the secreted proteins produced by wild-type S. pyogenes to a codY mutant thepost-exponential phase of growth. We used both one and two-dimensional gel electrophoresisto separate exoproteins. Proteins that were significantly different in abundance upon repeatedanalysis were identified with tandem mass spectrometry. The production of the secretedcysteine protease SpeB, a secreted chromosomally encoded nuclease (SdaB), and a putativeadhesion factor (Spy49_0549) were more abundant in supernatant fluids obtained from thecodY mutant. In addition, hyaluronidase (HylA), CAMP factor (Cfa), a prophage encodednuclease (Spd-3), and an uncharacterized extracellular protein (Spy49_0015) were lessabundant in supernatant fluids obtained from the codY mutant strain. Enzymatic assaysshowed greater DNase activity in culture supernatants isolated in the post-exponential phaseof growth from the codY mutant strain compared to the wild-type strain. Becauseextracellular nucleases and proteases can influence biofilm formation, we also measured theability of the strains to form biofilms during growth with both rich medium (Todd Hewittyeast extract; THY) and chemically defined media (CDM). No difference was observed with rich media but with CDM the biofilms formed by the codY mutant strain had less biomasscompared to the wild-type strain.Conclusions:Overall, the results indicate that CodY alters the abundance of a select group of S. pyogenesexoproteins, including DNases, a protease, and hylauronidase, which together may alleviatestarvation by promoting dissemination of the pathogen to nutrient rich environments and byhydrolysis of host macromolecules.

Identificador: doi:10.1186/1471-2180-12-114
Volume: 0
Página: 1 a

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