Gene expression anlayses of saliva-derived in vitro biofilms during carbohydrate fermentation and pH stress

Dental caries, one of the most globally widespread infectious diseases is intimately linked to pH dynamics. In supragingival plaque, after the addition of a carbohydrate source, bacteria rapidly decrease the pH which then subsequently recovers. In this project we studied gene transcription in naturally diverse saliva-derived in vitro grown biofilms as they were amended with sugar (corresponding to a dietary intake of carbohydrates). We applied an in vitro biofilm model system that was previously determined to be functionally and taxonomically robust and representative of health-associated dental plaque. The major goal was to characterize critical gene expression mechanisms supporting the understudied pH-recovery stage associated with health. This study provides a solid baseline for defining healthy and disease-like states and highlights the power of moving beyond single and dual species applications to capture key players and their orchestrated metabolic activities within a human oral microbiome model.