MICROSOME DISTRIBUTION DURING GERMINATION OF BACTERIAL SPORES

Abstract

The extractable microsome fraction of germinating spores of Bacillus subtilis was characterized by ultracentrifugal methods. Vegetative forms of B. subtilis contain 4 classes of extractable microsomes characterized by sedimentation constants of 33, 50, 68, and 99 S; spore extracts contain only 50 and 68 S particles in detectable amounts. During germination there are initial rapid increases in the amounts of 33 and 50 S particles, but a lag before increase in the amount of 70 or 100 S particles. The major portion of the ribonucleic acid of the spore and early germinating form probably does not exist as microsomal material, extractable or not. This result is in contrast to the finding for vegetative forms that the bulk of cellular ribonucleic acid can be extracted as microsomes.