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Updated: Dec 23, 2025

Microtiter Dish Biofilm Formation Assay
Published on: January 30, 2011
Biofilm Formation by Streptococcus mutans is Enhanced by Indole via the Quorum Sensing Pathway
Tomohiro Inaba1, Nozomu Obana2, Hiroshi Habe1
1Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).
Abstract:
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.
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