Spontaneous (A) and Triton X-100 (TX)-induced (B) autolysis of S. tigurinus strains AZ_3aT (C), 1366 (D), 2425 (E), and 2426 (F). The mean values of three independent experiments performed in triplicate are shown. The error bars are standard deviations. The statistical analyses shown in panels A and B were performed between the parental strain 1366 and the SCVs 2425 (asterisks above curve) and 2426 (asterisks below curve), respectively. *, P < 0.05; **, P < 0.01.