Function of the pyruvate oxidase-lactate oxidase cascade in interspecies competition between Streptococcus oligofermentans and Streptococcus mutans.

ABSTRACT: Complex interspecies interactions occur constantly between oral commensals and the opportunistic pathogen Streptococcus mutans in dental plaque. Previously, we showed that oral commensal Streptococcus oligofermentans possesses multiple enzymes for H(2)O(2) production, especially lactate oxidase (Lox), allowing it to out-compete S. mutans. In this study, through extensive biochemical and genetic studies, we identified a pyruvate oxidase (pox) gene in S. oligofermentans. A pox deletion mutant completely lost Pox activity, while ectopically expressed pox restored activity. Pox was determined to produce most of the H(2)O(2) in the earlier growth phase and log phase, while Lox mainly contributed to H(2)O(2) production in stationary phase. Both pox and lox were expressed throughout the growth ph

SUBMITTER: Liu L 

PROVIDER: S-EPMC3302633 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature