NATURE OF RIBOSOMES OF SPORES OF BACILLUS CEREUS T AND BACILLUS MEGATERIUM

The characteristics of ribosomes from spores of Bacillus cereus T. and Bacillus megaterium were compared and found to be similar when isolated under identical conditions. Ribosomes isolated by mechanical disruption from dormant spores sediment as 70 S, 50 S, and 30 S particles; have low activity in the amino acid-incorporating system and bind aminoacyl-tRNA poorly. In contrast, polysomes and active ribosomes could be isolated from germinated spores of B. megaterium or spores which had been activated by treatment with mercaptoethanol and urea and lysed with lysozyme. In this procedure, germination of the spores precedes lysis. After germination and before lysis, new RNA is synthesized and polysomes appear. The impaired activity of ribosomes isolated from dormant spores could not be attributed to ribonuclease activity. © 1969.