FIG. 6.

Lyticase sensitivities of cells of wild type (A and C) and Δspi1 (B and D) strains that were grown in the absence of 2,4-D and then incubated in growth medium unsupplemented (A and B) or supplemented with 0.3 mM 2,4-D (C and D) and harvested during the growth represented by the growth curves shown in Fig. 3, specifically, at time zero, after 2.5 h of incubation, and at the exponential phase when culture OD₆₀₀ reached 1 (Exp). The different cell populations were washed with water and resuspended in 0.1 M sodium phosphate buffer, pH 7.5. After addition of 10 μg of lyticase (Sigma) per ml, the decrease in the OD₆₀₀ of the cell suspension was measured periodically. Data are the means ± standard deviations of at least three independent experiments.