luxS Mutant Regulation: Quorum Sensing Impairment or Methylation Disorder?

Sensors

Qian Wang¹  Zhiyan He¹  Yuejian Hu¹  Yuntao Jiang¹  Rui Ma¹  Zisheng Tang¹  Jingping Liang¹  Zheng Liu¹ 

[1] Department of Endodontics, Ninth People's Hospital, Shanghai Key Laboratory of Stomatology, School of Medicine, Shanghai Jiao Tong University, No. 639 Zhizaoju Road, Shanghai 200011, China; E-Mails:

关键词: quorum sensing;    AI-2;    luxS;    sahH;   

DOI  :  10.3390/s120506176

来源: mdpi

【 摘 要 】

AI-2–mediated quorum sensing has been identified in various bacteria, including both Gram-negative and Gram-positive species, and numerous phenotypes have been reported to be regulated by this mechanism, using the luxS-mutant strain. But the AI-2 production process confused this regulatory function; some considered this regulation as the result of a metabolic change, which refers to an important metabolic cycle named activated methyl cycle (AMC), caused by luxS-mutant simultaneously with the defect of AI-2. Herein we hypothesized that the quorum sensing system—not the metabolic aspect—is responsible for such a regulatory function. In this study, we constructed plasmids infused with sahH and induced protein expression in the luxS-mutant strain to make the quorum-sensing system and metabolic system independent. The biofilm-related genes were investigated by real-time polymerase chain reaction (PCR), and the results demonstrated that the quorum-sensing completed strain restored the gene expression of the defective strain, but the metabolically completed one did not. This evidence supported our hypothesis that the autoinducer-2-mediated, quorum-sensing system, not the AMC, was responsible for luxS mutant regulation.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland