| Title |
Functional Definition of LuxS, an Autoinducer-2 (AI-2) Synthase and Its Role in Full Virulence of Streptococcus suis Serotype 2 |
| Author |
Min Cao1,2, Youjun Feng2,3, Changjun Wang2, Feng Zheng1,2, Ming Li1, Hui Liao2, Yinghua Mao2, Xiuzhen Pan2, Jing Wang2, Dan Hu2, Fuquan Hu1*, and Jiaqi Tang1,2,4* |
| Address |
1Department of Microbiology, Third Military Medical University, Chongqing, P. R. China, 2Department of Epidemiology, Research Institute for Medicine of Nanjing Command, Nanjing, P. R. China, 3Clinical Microbiology & Clinical Immunology, Third Military Medical University, Chongqing, P. R. China, 4Department of laboratory Sciences, Nanjing General Hospital of Nanjing Military Command, Nanjing, P. R. China |
| Bibliography |
Journal of Microbiology, 49(6),1000-1011, 2011,
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| DOI |
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| Key Words |
Streptococcus suis, Quorum sensing, Autoinducor 2 (AI-2), LuxS |
| Abstract |
Quorum sensing is a widespread chemical communication in response to fluctuation of bacterial population density, and has been implicated into bacterial biofilm formation and regulation of expression of virulence factors. The luxS gene product, S-ribosylhomocysteinase, catalizes the last committed step in biosynthetic pathway of autoinducer 2 (AI-2), a signaling molecule for inter-species quorum sensing. We found a luxS homologue in 05ZYH33, an epidemic strain of Streptococcus suis serotype 2 (SS2) in China. A luxS null mutant (ΔluxS) of 05ZYH33 strain was obtained using an approach of homologous recombination. LuxS was determined to be required for AI-2 production in 05ZYH33 strain of S. suis 2. Inactivation of luxS gene led to a wide range of phenotypic changes including thinner capsular walls, increased tolerance to H2O2, reduced adherence capacity to epithelial cells, etc. In particular, loss of LuxS impaired dramatically its full virulence of SS2 in experimental model of piglets, and functional complementation restored it nearly to the level of parent strain. Genome-wide transcriptome analyses suggested that some known virulence factors such as CPS are down-regulated in the ΔluxS mutant, which might in part explain virulence attenuation by luxS deletion. Similarly, 29 of 71 genes with different expression level were proposed to be targets candidate regulated by LuxS/AI-2-dependent quorum sensing. |
