[Complementation and function of methyl-metabolic pathway in Streptococcus mutans luxS null strain].

ABSTRACT

PURPOSE: To complement the activated methyl cycle (AMC) pathway at an AI-2 defect background in Streptococcus mutans (S. mutans) luxS null strain. METHODS: A sahH gene was amplified from Pseudomonas aeruginosa and introduced into the S. mutans luxS null strain to complement the methyl-metabolic disruption at an AI-2 defect background. Western blot, reverse-transcription PCR and AI-2 bioassay were performed to confirm the heterogenous expression of SahH in S. mutans luxS null strain. The data was statistically analyzed by SAS8.0 software package. RESULTS: LuxS and SahH were detected to express in Escherichia coli BL21 as well as their mRNA were confirmed to be successfully transcribed in S. mutans luxS null strain. AI-2 production was found in wide type S. mutans and its luxS-introduced luxS null strain but not found in the luxS null strain and its sahH and empty plasmid-introduced strains. CONCLUSIONS: A new S. mutans derivative with the AMC pathway complements while the AI-2 defect is constructed.