Azakami Hiroyuki, Teramura Izumi, Matsunaga Tetsuro, Akimichi Hiromi, Noiri Yuichiro, Ebisu Shigeyuki, Kato Akio
Department of Biological Chemistry, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan.
J Biosci Bioeng. 2006 Aug;102(2):110-7. doi: 10.1263/jbb.102.110.
Quorum sensing (QS) is a process by which bacteria communicate using secreted chemical signaling molecules called autoinducers (AIs). By this process, many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density. In this study, the periodontal pathogen Eikenella corrodens was observed to secrete type 2 signaling molecules. An ortholog of luxS, the gene required for AI-2 synthesis in Vibrio harveyi, was isolated from the E. corrodens genome. A V. harveyi bioassay showed luxS functionality in E. corrodens and the ability of luxS to complement the luxS-negative phenotype of Escherichia coli DH5alpha. AI activity was detected in the supernatant, and the maximum expression of AI-2 was observed during the late exponential phase. To determine the potential role of luxS in the colonization processes, an E. corrodens luxS mutant was constructed and tested for its capacity to form an in vitro biofilm on a polystyrene surface. The biofilm forming efficiency of the luxS mutant was approximately 1.3-fold greater than that of the wild type. These data suggest that a LuxS-dependent signal plays a role in the biofilm formation by E. corrodens.
群体感应（QS）是细菌利用称为自诱导物（AIs）的分泌化学信号分子进行通讯的过程。通过这个过程，许多细菌物种会根据种群密度的变化来调节多种生理功能的表达。在本研究中，观察到牙周病原体腐蚀艾肯菌分泌2型信号分子。从腐蚀艾肯菌基因组中分离出哈维氏弧菌中AI-2合成所需基因luxS的直系同源基因。哈维氏弧菌生物测定表明luxS在腐蚀艾肯菌中具有功能，并且luxS能够补充大肠杆菌DH5α的luxS阴性表型。在上清液中检测到AI活性，并且在指数后期观察到AI-2的最大表达。为了确定luxS在定殖过程中的潜在作用，构建了腐蚀艾肯菌luxS突变体，并测试其在聚苯乙烯表面形成体外生物膜的能力。luxS突变体的生物膜形成效率比野生型高约1.3倍。这些数据表明，依赖LuxS的信号在腐蚀艾肯菌的生物膜形成中起作用。
