FIG 7.

Exogenous pyruvate improves persistence of S. sanguinis. S. mutans UA159 and S. sanguinis strain SK36 (MMZ1896) and its isogenic manL mutant were each (n = 3) cultured overnight in BHI medium supplemented with or without 5 mM pyruvate. The next day, cultures were diluted and plated for viable CFU counts (A) or for assessment of growth characteristics (B, C) by diluting into TY-Glc medium with or without 5 mM pyruvate. Panel B shows the effects of pyruvate in overnight cultures of UA159 and SK36 by diluting them into TY-Glc without pyruvate, and panel C shows the effects of pyruvate added to fresh TY-Glc by diluting from overnight cultures prepared without pyruvate. Each of the columns and the growth curves represents the average of three biological replicates. Asterisks denote the statistical significance (P < 0.05) obtained using Student’s t test.