FIG. 5.

Germination of individual B. subtilis spores as a function of the concentrations of l-valine (A) or AGFK (B). Heat-activated (75°C) B. subtilis spores were germinated at 34°C in HEPES buffer for l-valine germination, and the percentages of spores that germinated in various 10-min periods were determined as described in Materials and Methods using method B. For AGFK germination, the concentration of only A, G, and F were varied, and the concentration shown is that of each of these individual components, while the KPO₄ buffer concentration was constant at 12.5 mM. The symbols used (and the percentage of spores that had germinated in 90 min and the total number of spores analyzed) are as follows: panel A, ○, 10 mM l-valine (99% of 413 spores), •, 1 mM l-valine (95% of 395 spores), ▵, 0.65 mM l-valine (88% of 519 spores), ▴, 0.3 mM l-valine (60% of 485 spores), and □, 0.2 mM l-valine (16% of 561 spores); panel B, ○, 1.4 mM AGFK (98% of 480 spores), •, 0.45 mM AGFK (80% of 490 spores), ▵, 0.15 mM AGFK (53% of 564 spores), and ▴, 0.1 mM AGFK (28% of 492 spores). In the absence of AGFK or l-valine, there was ≤1% germination of these spores in 120 min. Note that (i) the values given on the vertical axis are the percentage 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.