This review summarizes the main results obtained in the fields of general and molecular microbiology and microbial genetics at the Institute of Microbiology of the Academy of Sciences of the Czech Republic (AS CR) [formerly Czechoslovak Academy of Sciences (CAS)] over more than 50 years. Contribution of the founder of the Institute, academician Ivan Málek, to the introduction of these topics into the scientific program of the Institute of Microbiology and to further development of these studies is also included.

• MeSH
• Academies and Institutes history   MeSH
• History, 20th Century MeSH
• Genetics, Microbial history   MeSH
• Molecular Biology history   MeSH
• Check Tag
• History, 20th Century MeSH
• Publication type
• Journal Article MeSH
• Historical Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Geographicals
• Czech Republic MeSH

Intracellular proteolytic activities of B. megaterium KM occur soluble in the cytoplasm and periplasm and insoluble in the membrane. Two proteolytic enzymes were found in the cytoplasmic fraction by gel filtration on Sephadex G 150 and by polyacrylamide gel electrophoresis. The first enzyme called CI was stable, had a relative molecular mass of Mr = 105,000 (M = 105 kg/mol) and was inhibited by EDTA and PMSF, whereas the second, designated CII, was labile and had a relative molecular mass of Mr = 46,000 (M = 46 kg/mol). Because of its lability it could not be characterized in detail. In the "periplasm" only a single proteolytic enzyme P (Mr = 28,000; M = 28 kg/mol) inhibited by EDTA could be demonstrated. The extracellular enzyme exhibited similar properties. The membrane proteolytic activity was sensitive to PMSF and EDTA. The membrane enzymes have not yet been solubilized. In cells of the mutant KM 12 that does not produce the extracellular proteinase, only one type of proteinase, in all its properties identical with the cytoplasmic proteinase CI, could be demonstrated.

• MeSH
• Bacillus megaterium enzymology   genetics   MeSH
• Electrophoresis, Polyacrylamide Gel MeSH
• Endopeptidases analysis   MeSH
• Chromatography, Gel MeSH
• Mutation MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Endopeptidases MeSH

A proteolytic activity hydrolyzing denatured proteins of Bacillus megaterium labelled with 35S or 14C amino acids was detected in cells of the asporogenic strain of Bacillus megaterium. The substrate is hydrolyzed by the enzyme or enzymes at optimum pH around 7, their activity being almost completely inhibited by EDTA and o-phenanthroline. PMSF, the inhibitor of serine proteases, is slightly inhibitory. Gel filtration on a Sephadex column separated the protease activity to two or three fractions. The protease activity in cells with the repressed synthesis of protease corresponds to 5-20 mug of substrate degraded per hour by 1 mg of protein at 37 degrees C. It increases five to ten-fold during the derepression. When the intracellular protease activity increases the extracellular enzyme begins to be excreted into the medium. The intracellular protease activity rapidly decreases after the addition of chloramphenicol or of a mixture of amino acids to the derepressed culture. Half or even more of the protease activity is released from the cells during their conversion to protoplasts by means of lysozyme. This "periplasmic" activity remains mostly in the supernatant also after mesosomes have been centrifuged down from the periplasm. A portion of the activity bound in protoplasts sediments together with membrane fraction after their lysis.

• MeSH
• Amino Acids MeSH
• Bacillus megaterium enzymology   MeSH
• Bacterial Proteins metabolism   MeSH
• Chloramphenicol pharmacology   MeSH
• Edetic Acid pharmacology   MeSH
• Enzyme Repression MeSH
• Ethanol pharmacology   MeSH
• Phenanthrolines pharmacology   MeSH
• Phenylmethylsulfonyl Fluoride pharmacology   MeSH
• Kinetics MeSH
• Hydrogen-Ion Concentration MeSH
• Molecular Weight MeSH
• Peptide Hydrolases analysis   biosynthesis   metabolism   MeSH
• Protoplasts MeSH
• Serine MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amino Acids MeSH
• Bacterial Proteins MeSH
• Chloramphenicol MeSH
• Edetic Acid MeSH
• Ethanol MeSH
• Phenanthrolines MeSH
• Phenylmethylsulfonyl Fluoride MeSH
• Peptide Hydrolases MeSH
• Serine MeSH