FIG 3.

Five-day growth-dependent acidification survival assay. S. epidermidis 1457, 1457 ΔarcA1, 1457 ΔarcA2, 1457 ΔADI, 1457 ΔADI/pNF232, and 1457 ΔADI/pNF233 were grown aerobically in TSB supplemented with 35 mM glucose and 5 mM arginine and sampled daily for determinations of cell density (A), extracellular pH (B), acetic acid (C), and ammonia concentration (D). Plasmids pNF232 and pNF233 contain the native (arcA1B1D1R1) and acquired (arcA2D2R2B2C2) ADI operons, respectively. Error bars represent standard deviations of the means for the results of three independent experiments.