FIG. 4.

Spore germination and outgrowth without prior heat activation and doubling times of different strains. (A) Wild-type (•) and nfo exoA (▪) dormant spores were germinated without a prior heat shock, and spore germination and outgrowth were measured by monitoring the OD₆₀₀ of the cultures as described in Materials and Methods. The results are representative, and the experiment was performed at least two times with different lots of spores, all of which produced similar results. (B) Overnight cultures of various strains were inoculated into 25 ml of LB medium, the cultures were shaken at 37°C, and the OD₆₀₀ of the cultures were monitored. The doubling times are the averages ± standard deviations for values obtained from two different cultures. WT, wild type.