Biomedical subjects

G Valu

Publications and source records attributed to G Valu.

4 recordsLinked to original sources

PubMed1979

Streptomycin sensitivity of ribosomes isolated from a streptomycin-producing Streptomyces griseus.

The streptomycin sensitivity of ribosomes derived from a streptomycin-producing Streptomyces griseus was examined in a polyuridylic acid directed 14C-phenylalanine incorporating system. In order to get reproducible results it is essential to use cell-free extracts which do not inactivate streptomycin. This condition can be fulfilled by the combination of washed ribosomes of the streptomycin-producing strain and the 110 000 g supernatant of the streptomycin-nonproducing variant of S. griseus, because the streptomycin-phosphorylating activity can be washed out from ribosomes of younger streptomycin-producing cultures, and the streptomycin-nonproducing S. griseus does not have any streptomycin-inactivating capacity. In this amino acid polymerizing system the ribosomes of the streptomycin-producing strain were as sensitive to streptomycin as the ribosomes of the nonproducing variant or of Escherichia coli.

Phenylalanine↗

PubMed1978

High molecular weight ribosomal ribonucleic acid from vegetative hyphae and spores of Streptomyces griseus.

High molecular weight ribosomal ribonucleic acids (rRNAs) were isolated from young vegetative cells and spores of a streptomycin non-producing Streptomyces griseus, and their electrophoretic mobility was compared to each other and to that of rRNAs of Escherichia coli K-12. The electrophoretic mobility of 23 and 16S rRNAs from vegetative cells and spores of S. griseus was identical, but the 23S rRNAs of streptomyces ribosomes migrated more slowly on polyacrylamide gel than those of E. coli ribosomes. Intact, electrophoretically homogenous rRNAs could be isolated from S. griseus (No. 45-H) only in the presence of diethyl 1 pyrocarbonate (DEP), and intact rRNAs could be obtained from spores only if DEP had been added before breaking the spores. Otherwise instead of two distinct bands, three were obtained on polyacrylamide gel.

Electrophoresis, Polyacrylamide Gel↗

PubMed1976

Proteolytic activity of subcellular fractions from Streptomyces griseus no. 45-H.

Subcellular fractions were prepared from Streptomyces griseus No. 45-H at different stages of life cycle, and their proteolytic activity was examined. The highest proteolytic activity was found in the 24- and 72- h-old vegetative hyphae, the lowest in the resting spores. Spores contained about 9--30% of the proteolytic activity of vegetative cells. At the age of 16 h about 80%, at 26 h 70%, at 72 h 40%, and in spores about 60% of the proteolytic activity was particulate. The greatest part of the proteolytic activity could be inhibited by EDTA, lower levels of serine and sulfhydryl protease activities were detected in the cell-free extracts of vegetative cells.

4-Chloromercuribenzenesulfonate↗

PubMed1975

Ribosomal proteins from vegetative hyphae and from spores of Streptomyces griseus.

Ribosomes from vegetative cells and spores of Streptomyces griseus have been used to prepare ribosomal proteins for polyacrylamide gel electrophoresis. Differences in the gel electrophoretic profile of proteins from vegetative cells and spore ribosomes can be detected. Spore ribosomes were stable during the isolation process, but in the case of vegetative cell ribosomes it was necessary to use protease inhibitor to obtain reproducible results. Suspensions of washed ribosomes of vegetative hyphae have higher proteolytic activity than ribosomes from spores.

Ribosomal Proteins↗