FIG. 3.

Growth of S. typhimurium 14028s derivatives in vitro. The growth rate was determined by measuring the optical density at 600 nm (OD₆₀₀) as a function of time. Wild-type (□), mutS (◊), recD (○), or mutS recD (▵) strains were either grown in rich medium and subcultured into rich medium (A), grown in minimal medium and subcultured into minimal medium (B), or grown in rich medium and subcultured into minimal medium (C). All assays were performed in 96-well microtiter dishes with a BioTek Instruments EL_x808 Automated Microdish Reader. Strains were routinely grown in 200-μl volumes and incubated at 37°C with shaking. Growth was monitored over 36 h by measuring the OD₆₀₀ at 15-min intervals. The values shown represent the mean optical densities from cultures grown in triplicate. The standard error was <5% of the mean for all time points measured.