Influence of L-malate and mleR on the growth of S. mutans. Cell were inoculated in acidified BMG (pH 6.0) medium under anaerobic conditions. A: Growth (OD600) of wildtype (black) and ΔmleR mutant (grey) in the absence (open symbols) or presence (filled symbols) of L-malate. B: pH and malate concentration of the supernatant of wildtype and ΔmleR mutant cultures grown in the presence of malate. Closed circle, pH of wildtype; Closed square, pH of the ΔmleR mutant; Open circle, malate concentration of wildtype; Open square, malate concentration of the ΔmleR mutant.