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Published on: June 28, 2018
[Phenotypic analysis of luxS gene deletion mutants and its application in virulence regulation research in group B
Qian Ouyang1, Wen-li Ma, Cui-hua Liu
1Institute of Genetic Engineering, Southern Medical University, Guangzhou 510515, China.
Objective:
To explore the mechanism of virulence regulation in group B streptococcus (BGS) by studying LuxS-related AI-2 quorum-sensing pathway in GBS.
Methods:
luxS gene deletion mutants of GBS (Delta lusX) were characterized by reverse transcription (RT)-PCR, colony immunoblot analysis, growth curve measurement, and cAMP determination. Functional analysis of luxS in the deletion mutants was conducted by bioluminescence assay.
Results:
Genetic analysis results showed that the luxS deletion in the mutant 515-Delta lusX caused upregulation of scpB gene expression. Phenotypic analysis revealed that, in comparison with the wild strain, 515-Delta lusX mutant grew slowly in DCM media but quickly in THY media. An approximately two-fold decrement in bioluminescence was detected in the luxS deletion mutants as compared with the wild strain.
Conclusion:
This study confirms the importance of LuxS molecule in the AI-2 quorum-sensing pathway in GBS and provides new insights into the virulence regulation mechanism of GBS.
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