FIG. 2.

(A, B) Effect of heat activation on commitment and DPA release during spore germination. Commitment (•, ▾) and DPA release (○, ▿) curves of spores of B. subtilis PS533 (wild-type) germinating in 2 mM l-alanine (A) and B. cereus germinating with 40 mM NH₄Cl plus 1 mM l-alanine (B) with (•, ○) or without (▾, ▿) prior heat activation were determined after d-alanine addition to germination incubations at various times as described in Materials and Methods. The maximum number of RFU that each germination assay reached upon germination for 2 h in panel A and for 30 min in panel B was set at 100%, but the actual germination percentages of spore samples at the end of germination incubations were 95 and 68% in panels A and B, respectively.