Fig. 2

Measurement of extracellular pyruvate during growth of S. mutans wild-type, ΔlrgAB, and ΔlytS strains in low-glucose media. The strains, including wild type UA159 (a), ΔlrgAB (b), and ΔlytS (c) strains, were grown in a chemically defined medium (FMC) supplemented by 11 mM glucose. For time course measurements of extracellular pyruvate and growth, samples were taken at 1 or 2 h intervals (see Materials and Methods for details). The concentration of pyruvate was determined using an EnzyChrom™ pyruvate assay kit, and growth was measured by the optical density at 600 nm (OD₆₀₀). Bars indicates the average concentration of extracellular pyruvate; solid line with circles indicates the corresponding growth curve. The results are average of two independent experiments. Error bars = standard deviation