A shift from oral to blood pH is a stimulus for adaptive gene expression of Streptococcus gordonii CH1 and induces protection against oxidative stress and enhanced bacterial growth by expression of msrA.

ABSTRACT: Viridans group streptococci (VS) from the oral cavity entering the bloodstream may initiate infective endocarditis (IE). We aimed to identify genes expressed in response to a pH increase from slightly acidic (pH 6.2) to neutral (pH 7.3) as encountered by VS entering the bloodstream from the oral cavity. Using a recently developed promoter-screening vector, we isolated five promoter fragments from the genomic DNA of Streptococcus gordonii CH1 responding to this stimulus. No common regulatory sequences were identified in these promoter fragments that could account for the coordinate expression of the corresponding genes. One of the isolated fragments contained the promoter region and 5' end of a gene highly homologous to the methionine sulfoxide reductase gene (msrA) of various bacterial and

SUBMITTER: Vriesema AJ 

PROVIDER: S-EPMC97249 | biostudies-literature | 2000 Mar

REPOSITORIES: biostudies-literature