LuxS-Based Signaling Affects Streptococcus mutans Biofilm Formation
LuxS-Based Signaling Affects Streptococcus mutans Biofilm Formation
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DOI：
10.1128/aem.71.5.2372-2380.2005
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发表时间：
2005-05
影响因子：
4.4
通讯作者：
A. Yoshida;T. Ansai;T. Takehara;H. Kuramitsu
中科院分区：
文献类型：
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作者：
A. Yoshida;T. Ansai;T. Takehara;H. Kuramitsu
变形链球菌是人类龋病的主要病原菌，其重要毒力特征之一是能在牙齿表面形成生物膜(牙菌斑)。我们通过构建GS-5 LuxS-空突变体，研究了自身诱导物-2(AI-2)在变形链球菌生物膜形成中的作用。与野生型相比，该突变株在0.5%蔗糖定义的培养基中形成的生物膜明显减弱。扫描电子显微镜还显示，与亲本菌株相比，LuxS突变体的生物膜在蔗糖介质中形成了更大的团块。因此，对葡萄糖转移酶基因的表达进行了检测，并在对数生长期中期上调了突变株的gtfb和gtfc基因，而不是gtfD基因。此外，我们开发了一种新的两室系统来监测口腔链球菌和牙周病细菌产生AI-2。Gordonii、S.sobrinus和S.anginosus菌株补充了LuxS突变体的生物膜缺陷，而口腔链球菌、唾液链霉菌和血链球菌没有补充。牙龈卟啉单胞菌381和伴放线放线杆菌Y4也补充了LuxS突变体形成的生物膜，但没有得到牙龈卟啉单胞菌LUX S突变体的补充。这些结果表明，依赖蔗糖的生物膜形成所需的葡萄糖基转移酶基因的调控受AI-2的调控。此外，这些结果进一步证实了先前的建议，即通过AI-2进行的群体感应可能在口腔生物膜的形成中发挥重要作用。
ABSTRACT Streptococcus mutans is implicated as a major etiological agent in human dental caries, and one of the important virulence properties of this organism is its ability to form biofilms (dental plaque) on tooth surfaces. We examined the role of autoinducer-2 (AI-2) on S. mutans biofilm formation by constructing a GS-5 luxS-null mutant. Biofilm formation by the luxS mutant in 0.5% sucrose defined medium was found to be markedly attenuated compared to the wild type. Scanning electron microscopy also revealed that biofilms of the luxS mutant formed larger clumps in sucrose medium compared to the parental strain. Therefore, the expression of glucosyltransferase genes was examined and the gtfB and gtfC genes, but not the gtfD gene, in the luxS mutant were upregulated in the mid-log growth phase. Furthermore, we developed a novel two-compartment system to monitor AI-2 production by oral streptococci and periodontopathic bacteria. The biofilm defect of the luxS mutant was complemented by strains of S. gordonii, S. sobrinus, and S. anginosus; however, it was not complemented by S. oralis, S. salivarius, or S. sanguinis. Biofilm formation by the luxS mutant was also complemented by Porphyromonas gingivalis 381 and Actinobacillus actinomycetemcomitans Y4 but not by a P. gingivalis luxS mutant. These results suggest that the regulation of the glucosyltransferase genes required for sucrose-dependent biofilm formation is regulated by AI-2. Furthermore, these results provide further confirmation of previous proposals that quorum sensing via AI-2 may play a significant role in oral biofilm formation.