Figure 3.
Growth and survival kinetics from S. aureus 132 Δdat Δalr1 Δalr2. Cells grown in overnight cultures in TSB supplemented with D-alanine were pelleted, washed, and resuspended in fresh medium in the presence or absence of 5 mM D-alanine. A. Growth was monitored by measuring the turbidity (OD at 600 nm) at different times. B. Culture viability (Log10 CFU per milliliter) on TSA containing 5 mM D-alanine after growth with or without D-alanine. S. aureus 132 Δdat Δalr1 Δalr2 shows normal growth in TSB supplemented with 5 mM D-alanine, but it is not able to grow without the exogenous supply of this compound. In contrast, the isogenic parental strain grows as per normal in TSB either with or without D-alanine. Squares and circles represent the wild type strain and the triple mutant, respectively in the presence (closed symbols) or the absence (open symbols) of D-alanine.