FIG 1.

Germination of B. subtilis 2-, 47-, and 98-day spores with various germinants. Spores were harvested from sporulation plates incubated for 2, 47, or 98 days, highly purified as described in Materials and Methods, and germinated with either l-valine (A), dodecylamine (B), or Ca-DPA (C). Spore germination was monitored by measuring either Ca-DPA release by fluorometry (A and B) or generation of dark spores in phase-contrast microscopy (C), with 100 spores examined at all time points for each spore preparation. The symbols used are as follows: ○, 2-day spores; ●, 47-day spores; and ▵, 98-day spores. This experiment was carried out twice, with essentially identical results.