FIG. 1.
Effect of d-Ala depletion on growth and lysis of L. lactis PH3960. (A) Growth and lysis, as measured by following the OD600, of L. lactis strains NZ3900 (control) and PH3960 (Δalr) in the presence and absence of d-Ala. The strains were grown in GM17 supplemented with 2 mM d-Ala until an OD600 of 0.6 was reached. Subsequently, the cultures were split: one half was grown in GM17 with 2 mM d-Ala while the other half was grown without d-Ala. (B) Growth and lysis of PH3960 (Δalr) after d-Ala depletion and in the presence of 0.5 M sucrose or 0.5 M NaCl. Similar results were obtained in independent experiments.