FIG. 3.

Distribution of germination times of spores of B. cereus during germination of heat-activated (A and B) and unactivated (C) spores with various l-alanine (A) or inosine (B and C) concentrations. B. cereus spores were germinated with or without heat activation (70°C) at pH 8.8, and the percentages of individual spores germinating at 25°C (A) or 34°C (B and C) in various 10-min periods were determined as described in Materials and Methods using method B. The symbols used (and the percentage of spores that had germinated in 90 min and total number of spores analyzed) are as follows: panel A, ○, 5 mM l-alanine (99% of 887 spores), •, 2 mM l-alanine (89% of 1,002 spores), ▵, 1 mM l-alanine (60% of 606 spores), and ▴, 0.3 mM l-alanine (28% of 489 spores); panel B, ○, 5 mM inosine (100% of 536 spores), •, 0.3 mM inosine (99% of 464 spores), ▵, 30 μM inosine (87% of 394 spores), ▴, 20 μM inosine (71% of 398 spores), and □, 0.085 μM inosine (25% of 363 spores); and panel C, ○, 1 mM inosine (99% of 450 spores), •, 0.3 mM inosine (98% of 441 spores), ▵, 0.1 mM inosine (85% of 347 spores), ▴, 50 μM inosine (60% of 468 spores), and □, 30 μM inosine (21% of 614 spores). In the absence of l-alanine or inosine, there was ≤1% germination of these spores in 90 min. Note that (i) the values given on the vertical axis are the percentages of spores that germinated in a particular 10-min period in the experiment and (ii) the latter values have been normalized to the total number of spores that germinated in the complete experimental period of the experiment.