FIG. 2.

Spontaneous germination of ger3 spoVF spores prepared with different DPA concentrations. Spores of strain FB108 (ger3 spoVF) prepared with different DPA levels as described in the legend to Fig. 1 were incubated at an OD₆₀₀ of 1 at 37°C in 10 mM KPO₄ buffer (pH 7.5). At various times 1-ml samples were taken and stained with the dye Syto 16, and the degree of spore germination was determined by flow cytometry as described in Materials and Methods. Spores were prepared with different DPA concentrations as follows: ○, no DPA; •, 3 μg/ml DPA; ▵, 6 μg/ml DPA, ▴, 50 μg/ml DPA; and □, 300 μg/ml DPA. ▪, germination of spores of strain FB72 (ger3) analyzed similarly.