Interspecies interactions among oral microorganisms in the pathogenic biofilms causing dental caries have not yet been elucidated in detail. We herein demonstrated that indole and its derivatives induced biofilm formation by Streptococcus mutans. Indole is an intercellular signaling molecule that is produced by oral bacteria other than S. mutans. The amounts of biofilm and extracellular DNA were significantly increased by the addition of indole and 4-hydroxyindole (4-HI). An examination with quorum sensing mutants showed that the induction of biofilm formation by indole and 4-HI required a quorum sensing system. These results suggest that this intercellular signaling molecule plays a role in pathogenic biofilm formation.

中文翻译：

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吲哚通过群体感应通路增强变形链球菌的生物膜形成

导致龋齿的致病生物膜中口腔微生物之间的种间相互作用尚未详细阐明。我们在此证明吲哚及其衍生物诱导变形链球菌生物膜形成。吲哚是一种细胞间信号分子，由变形链球菌以外的口腔细菌产生。通过添加吲哚和 4-羟基吲哚 (4-HI)，生物膜和细胞外 DNA 的数量显着增加。对群体感应突变体的检查表明，吲哚和 4-HI 诱导生物膜形成需要群体感应系统。这些结果表明这种细胞间信号分子在致病生物膜形成中起作用。