Figure 2.

Change of PlrgA activity during growth of S. mutans UA159 wild type and ΔlrgAB mutant strains in FMC2 medium, supplemented by different concentrations of extracellular pyruvate. For measurement of PlrgA activation, the PlrgA-gfp reporter strain in the wild type (top panel) and ΔlrgAB (bottom panel) backgrounds was grown in FMC2 medium, supplemented by 0 (a and e), 1 (b and f), 10 (c and g) and 40 mM (d and h) of pyruvate (pyr). Relative gfp expression (green circle) and cell growth (white diamond) were monitored during growth on a plate reader (see Materials and Methods for details). The results are representative of three independent experiments.