Metabolic requirements for microcycle sporogenesis of Bacillus megaterium.

Spores of Bacillus megaterium QM B1551 germinated, elongated, and resporulated (microcycle sporogenesis) in simple chemically defined media which permitted no cell division. The second-stage spores thus produced were heat-stable and required heat activation for germination. The original amount of spore deoxyribonucleic acid tripled before completion of the cycle. Acetate and a small amount of a tricarboxylic acid cycle intermediate were the minimal organic metabolic requirements for microcycle sporogenesis. During this cycle, germinated cells oxidized acetate only after a delay, whether or not glucose was initially present. Spores that were germinated in the absence of a carbon source first oxidized an endogenous substrate, and then developed the ability to oxidize acetate.