FIGURE 3.

Polymicrobial cariogenic biofilm viability is influenced by carbohydrate source. (A) Polymicrobial caries biofilm model containing standardized L. casei, V. dispar, F. nucleatum, A. naeslundii and S. mutans isolates derived from either caries and caries-free patients grown at was grown in artificial saliva (AS) + galactose or sucrose at 37°C in 5% CO₂ for 5 days, with spent supernatants being replaced with fresh AS every 24 h. Metabolic activity (AlamarBlue) was quantified spectrophotometrically at 490 nm. Significant increase in growth compared to the 24 h culture (^∗∗p < 0.01, ^∗∗∗p < 0.001,^††p < 0.01). The total viable percentage composition of each bacterium in AS + 1% sucrose from (B) caries free and (C) caries derived S. mutans was quantified using species-specific qPCR (^∗∗∗p < 0.001). Significant difference between the contribution of Lactobacillus at 24 h and other time-points indicated (^∗∗∗p < 0.001). Significant difference between the contribution of S. mutans at 24 h and the time-points indicated (^†††p < 0.001). (D) A heatmap and clustering was created for the differential expression of genes (log₂). These distinct patterns of gene expression show the related expression profiles of srtA, gtfB, and ftf, and overall upregulation of all genes at 120 h.