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Biomedical subjects

S Osawa

Publications and source records attributed to S Osawa.

At least 199 records · Page 11Linked to original sources
PubMed1978

Mapping by interspecies transformation experiments of several ribosomal protein genes near the replication origin of Bacillus subtilis chromosome.

Bacillus subtilis 168 was transformed with DNAs from B. amyloliquefaciens K or B. licheniformis IAM 11054. These two species show a considerable difference in ribosomal proteins from B. subtilis. Analyses of the transformants indicated that the genes for 16 proteins, S3, S5, S8, S12, S17, S19, BL1, BL5, BL6, BL8, BL14, BL16, BL17, BL22, BL23 and BL25 are located in the cysA-str-spc region on B. subtilis chromosome. The genes for 10 proteins, S4, S6, S13, S16, S20, BL15, BL18, BL20, BL24 and BL28 could not be found in this region in the present experiments.

Bacillus↗
PubMed1978

Evolution of ribosomal proteins in Enterobacteriaceae.

The evolution of ribosomal proteins of about 70 bacterial strains belonging to the family Enterobacteriaceae has been studied by use of previously reported data (S. Osawa, T. Itoh, and E. Otaka, J. Bacteriol. 107:168-178, 1971) and those obtained in this paper. The proximity of the bacteria was quantified by co-chromatographing the differentially labeled ribosomal proteins from two strains on a column of carboxymethyl cellulose in various combinations. The were then classified into 12 groups (=species?) according to their ribosomal protein compositions and were placed in a phylogenic tree.

Bacterial Proteins↗
PubMed1977

The rates of evolution in some ribosomal components.

The rate of nucleotide substitution (k(nuc)) of 5s RNA was estimated to be (1.8 +/- 0.5) x 10(-10) per site per year by comparing the nucleotide sequences of human and Xenopus 5s RNA and using the geological time elapsed since the separation of mammals and amphibians. Similarly, k(nuc) of 5.8s rRNA was calculated to be 0.93 10(-1u) per site per year from the sequences of rat hepatoma cells and Saccbaromyces cerevisiae. For the comparison of these data with the amino acid substitution rate of known proteins, the k(nuc) values of 5s rRNA and 5.8s rRNA were converted to the rate of amino acid substitution (k(aa')). The k(aa') values in pauling units were 0.4 and 2 0.3, respectively. The average k(aa) of ribosomal proteins was also estimated to be 0.2 0.3 pauling from the N-terminal amino acid sequences of seventeen 30s ribosomal proteins of Bacillus stearothermopbilus and Eschericbia coli. Thus, the evolutionary rates of these ribosomal components studied here are similar to each other; they considerably slower than that of the known cellular proteins. Most, if not all, of the replacements in ribosomal proteins occurred between amino acids of a chemically similar nature.

Animals↗
PubMed1975

Correlation of 30S ribosomal proteins of Escherichia coli fractionated on carboxymethyl-cellulose column chromatography to the standard nomenclature.

The nomenclature proposed by Otaka et al. (1968) for the 30S ribosomal protein components of Escherichia coli as separated by carboxymethyl(CM)-cellulose column chromatography was adopted in several papers in which the genetic loci for many 30S ribosomal proteins on the E. coli chromosome were determined. In order to compare these data with those obtained in other laboratories, the 30S ribosomal proteins fractionated by CM-cellulose chromatography were correlated with thestandard nomenclature proposed by Wittmann et al. (1971).

Bacterial Proteins↗
PubMed1975

Ribosomal proteins from streptomycin-resistant and dependent mutants, and revertants from streptomycin-dependence to independence in Bacillus subtilis.

Streptomycin-resistant and dependent mutants were isolated from Bacillus subtilis ATCC 6633. Ribosomal proteins were analysed from six such mutants with chromatography on carboxymethyl cellulose or phosphocellulose columns. An altered specific 30s ribosomal protein, 30B, could be detected in all of these mutants. Streptomycin-independent revertants were isolated from a streptomycin-dependent strain. Some of them had an altered 30s ribosomal protein, 30A, and some others had an altered 30C protein. It was shown that from the data of partial N-terminal amino acid sequences together with amino acid compositions and mobilities on two-dimensional gel electrophoresis of these proteins that 30A, 30B, and 30C proteins were homologous with S5, S12 and S4 of E. coli 30s ribosomal proteins, respectively.

Amino Acid Sequence↗
PubMed1975

Effects of some antibiotics on the stringent control of RNA synthesis in Escherichia coli.

Effects of neomycin, spectinomycin, tetracycline and chloramphenicol on the stringent control RNA synthesis and on ppGpp synthesis in the rel+-cells of Escherichia coli having a temperature-sensitive valyl-tRNA synthetase were examined. Without antibiotics, ppGpp began to accumulate and both RNA and protein syntheses were inhibited by transferring the exponentially growing cells from 30 degrees C (permissive temp.) to 40 degrees C (non-permissive temp.). Tetracycline or chloramphenicol, when added after the temperature shift, caused a resumption of RNA synthesis and decay of the accumulated ppGpp, while neomycin or spectinomycin had little effect both on RNA synthesis and the level of ppGpp. When the cells were treated with these antibiotics at permissive temperature, the shift of the temperature to 40 degrees C caused neither inhibition of RNA synthesis nor an accumulation of ppGpp. When neomycin or spectinomycin was added at the beginning of the temperature shift, RNA synthesis continued with an accumulation of ppGpp. Tetracycline or chloramphenicol had no such effect under the same conditions; RNA synthesis continued without an accumulation of ppGpp.

Anti-Bacterial Agents↗