Criteria for categorizing early biochemical events occurring during sporulation of Bacillus subtilis.

Two criteria are suggested for assessing the relevance of biochemical events occurring early in sporulation. The first is thymidine starvation, a condition known to inhibit sporulation. This also inhibits the production of metalloprotease, serine protease, and ribonuclease; alpha-amylase production, however, is unaffected. The second is the effect of a regulator mutation which increases the production of the proteases. In the mutant, ribonuclease is produced in correspondingly large quantities whereas alpha-amylase production is unaffected. We conclude that, whereas the serine protease is part of the main sequence of events leading to formation of the spore, the metalloprotease is a side effect, i.e., connected with the main sequence but not part of it. Ribonuclease could, on present evidence, be either in the main sequence or a side effect associated with it. Amylase, however, seems to be separately regulated and neither directly nor indirectly connected with the sporulation sequence.