Studies on Bacterial Spore Resistance and Regulation of Activation.

Highlights of work on spores of Bacillus subtilis in the past performance period have included demonstration that 1 the zymogen of the spore protease GPR autoactivates, and that autoactivation is stimulated by low pH, dipicolinic acid and dehydration 2 most of the propeptide of GPR is not needed for zymogen stability or autoprocessing 3 the decrease in forespore pH in B. subtilis sporulation is responsible for 3-phosphoglycerate accumulation 4 alpha beta-type small, acid-soluble proteins in spores protect DNA against killing by freeze-drying, dry heat and several organic hydroperoxides, by preventing DNA damage 5 DNA repair during spore germination is an important component of resistance of spores to agents that kill spores through DNA damage and 6 spore resistance to peroxides is not due to the presence of protective enzymes such as catalases or alkylhydroperoxide reductases in spores.