Germinated spores of Bacillus megaterium were mutagenized with ethyl methanesulphonate and spread on test agar with caseinate. Colonies with altered proteolytic zones or morphology were isolated and tested in liquid media. The mutants can be divided into four groups: A) those producing more proteinase in both growth and sporulation media, B) those producing the same amount of the enzyme in growth medium but higher amount in sporulation medium, C) those producing less proteinase in the growth medium and more in the sporulation one, D) those producing less or no enzyme. Clones of the first three groups were phenotypically asporogenic. All mutants producing more enzyme during growth retained their sensitivity to repression by amino acids. Isolation of mutants of types B) and C) supports the idea of differences in the control of proteinase synthesis during growth and during sporulation.

• MeSH
• Bacillus megaterium enzymology   genetics   growth & development   MeSH
• Endopeptidases biosynthesis   MeSH
• Culture Media MeSH
• Mutation * MeSH
• Neprilysin MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Endopeptidases MeSH
• Culture Media MeSH
• Neprilysin MeSH

Abnormal proteins synthesized in the presence of ethionine were degraded more rapidly than the normal ones in cell-free extracts of ethanol-grown yeast. The denatured proteins, however, were degraded in preference to their native counterparts which were either normal or abnormal.

• MeSH
• Cell-Free System MeSH
• Protein Denaturation MeSH
• Ethionine metabolism   MeSH
• Fungal Proteins metabolism   MeSH
• Kinetics MeSH
• Saccharomyces cerevisiae metabolism   MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH
• Names of Substances
• Ethionine MeSH
• Fungal Proteins MeSH

During cultivation of Bacillus megaterium at 42 degrees C the amount of the exocellular protease produced by growing cells sharply decreases as compared with temperatures of 28 and 35 degrees C. Within the above range the growth rate and incorporation of amino acids increase with increasing temperature. The culture adapted to 42 degrees C does not produce more proteinase at this temperature than the non-adapted culture. The high temperature does not induce accumulation of the enzyme in the cells. Total protein excretion was slightly lower at 42 degrees C than at 28 and 35 degrees C.

• MeSH
• Bacillus megaterium enzymology   MeSH
• Bacterial Proteins metabolism   MeSH
• Endopeptidases biosynthesis   MeSH
• Hot Temperature MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Endopeptidases MeSH

Synthesis of exocellular metalloprotease and cellular and exocellular proteins in the sporogenic strain Bacillus megaterium J-27 and asporogenic strain KM 1 was investigated. Both organisms excrete the enzyme into the medium during growth and during the stationary phase. In the asporogenic strain the excretion decreases at the end of the exponential phase. In the sporogenic strain it continues during the transition to the stationary phase at the original rate and proteolytic activity in the medium increases two to three times during 2 h after the end of the exponential phase. Both organisms synthesize relatively more exocellular proteins during the exponential phase than during the stationary phase. The proportion of exocellular protein synthesized during the exponential phase does not exceed 3 % of total proteins, during the stationary phase this proportion usually decreases to less than 1 %.

• MeSH
• Bacillus megaterium growth & development   metabolism   MeSH
• Bacterial Proteins biosynthesis   MeSH
• Species Specificity MeSH
• Endopeptidases biosynthesis   MeSH
• Metalloendopeptidases MeSH
• Spores, Bacterial MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Endopeptidases MeSH
• Metalloendopeptidases MeSH

• MeSH
• Bacillus megaterium growth & development   metabolism   MeSH
• Bacterial Proteins metabolism   MeSH
• Kinetics MeSH
• Culture Media MeSH
• Mutation MeSH
• Peptide Hydrolases metabolism   MeSH
• Spores, Bacterial MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Culture Media MeSH
• Peptide Hydrolases MeSH

The rate of protein turnover in asporogenic Bacillus megaterium decreases continuously during incubation in a sporulation medium. The capability of equilibration of external amino acids with amino acids in the metabolic pool of non-growing cells was retained for at least 5 h. Leucine, while repressing the synthesis of the exocellular protease, does not significantly influence the course of protein degradation in vivo. Transfer of non-growing cells after 4 h to a fresh sporulation medium does not influence the rate of protein degradation. The gradual decrease of the rate of protein turnover in non-growing cells of the asporogenic variant is thus not an artifact caused by a decreased uptake of amino acids by cells or by conditions under which the protein turnover is determined.

• MeSH
• Amino Acids metabolism   MeSH
• Bacillus megaterium growth & development   metabolism   MeSH
• Bacterial Proteins metabolism   MeSH
• Kinetics MeSH
• Culture Media MeSH
• Leucine metabolism   MeSH
• Spores, Bacterial MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amino Acids MeSH
• Bacterial Proteins MeSH
• Culture Media MeSH
• Leucine MeSH

Functional half-life of the exocellular protease mRNA was determined in in exponentially growing and stationary cells of the asporogenic strain of Bacillus megaterium KM and in the sporogenic strain of B. megaterium 27 during sporulation. No reserve of the protease mRNA could be detected in the cells and the half-lives were determined to be 6--7 min in the exponential and stationary cells of B. megaterium KM and 7.5--8.5 min in B. megaterium 27. The mean half-life of mRNA for cell proteins was determined to be 3.5--4.5 min. Thus, as compared with the mean half-life of mRNA for cell proteins that of mRNA for the exocellular protease is slightly longer.

• MeSH
• Bacillus megaterium metabolism   physiology   MeSH
• Bacterial Proteins biosynthesis   MeSH
• RNA, Bacterial biosynthesis   metabolism   MeSH
• Dactinomycin pharmacology   MeSH
• Transcription, Genetic drug effects   MeSH
• RNA, Messenger metabolism   MeSH
• Half-Life MeSH
• Peptide Hydrolases biosynthesis   MeSH
• Spores, Bacterial MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• RNA, Bacterial MeSH
• Dactinomycin MeSH
• RNA, Messenger MeSH
• Peptide Hydrolases MeSH