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

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.