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Biomedical subjects

K Isono

Publications and source records attributed to K Isono.

At least 505 records · Page 28Linked to original sources
PubMed1979

Genes coding for ribosomal proteins S15, L21, and L27 map near argG in Escherichia coli.

Mutants with alterations in the structural genes for ribosomal proteins S15, L21, and L27 were used in mapping the genes coding for these proteins. Results from P1kc-mediated transductions indicate that the genes for L21 (rplU) and L27 (rpmA) form a gene cluster and are located between argG and gltB at 68.1 min, whereas the gene for S15 (rpsO) is situated close to, but on the opposite side or, argG. The gene order in this region is concluded to be gltB-(rplU, rpmA)-argG-rpsO-mtr.

Arginine↗
PubMed1978

Genes encoding ribosomal proteins S16 and L19 form a gene cluster at 56.4 min in Escherichia coli.

A mutant of Escherichia coli which was isolated for temperature-sensitive growth was found to harbour a structural alterations in protein S16 (Isolo et al., 1978). The mutation was localized by matings with various Hfr strains and by Plkc-mediated transduction. The results showed that it mapped very close to the gene coding for L19 protein which has been placed at 56.4 min (Kitakawa and Isono, 1977), indicating that it most likely forms a new ribosomal protein-gene cluster.

Chromosome Mapping↗
PubMed1978

Mutations affecting the structural genes and the genes coding for modifying enzymes for ribosomal proteins in Escherichia coli.

Temperature-sensitive mutants of an Escherichia coli K-12 strain PA3092 have been isolated following mutagenesis with nitrosoguanidine, and their ribosomal proteins analyzed by two-dimensional gel electrophoresis. This method was found to be very efficient in obtaining mutants with various structural alterations in ribosomal proteins. Thus a total of some 160 mutants with alterations in 41 different ribosomal proteins have so far been isolated. By characterizing these mutants, we could isolate not only those mutants with alterations in the structural genes for various ribosomal proteins, but also those with impairments in the modification of proteins S5, S18 and L12. Furthermore, a mutant has been obtained which apparently lacks the protein S20 (L26) with a concomitant reduction to a great extent of the polypeptide synthetic activity of the small subunit. The usefulness of these mutants in establishing the genetic architecture of the genes coding for the ribosomal proteins and their modifiers is discussed.

Electrophoresis↗
PubMed1978

Origin of nitrogen in the biosynthesis of carbamoylpolyoxamic acid.

The biosynthetic origin of the carbamoylpolyoxamic sidechain of the polyoxin nucleoside peptide antibiotics was studied using 15N labeled alpha-amino-S-hydroxyvaleric acid as precursor. Gas chromatography mass spectrometry of polyoxamic acid isolated from culture filtrates of Streptomyces cacaoi var. asoensis showed incorporation of the nitrogen atom of alpha-amino-S-hydroxyvaleric acid into carbamoylpolyoxamic acid with an isotopic dilution factor of 23, thus establishing the intermediacy of alpha-amino-S-hydroxyvaleric acid and determination of the full biosynthetic pathway.

Amino Acids↗
PubMed1978

Cluster of ribosomal protein genes in Escherichia coli containing genes for proteins S6, S18, and L9.

A mutant of Escherichia coli K-12 isolated for temperature-sensitive growth was found to harbor an alteration in robosomal protein L9. Because the chromosomal location of the structural gene for this protein (rplI) was not known, we mapped the mutation by using various Hfr strains. The fine mapping of this gene by Plkc phage-mediated transductions has revealed that it forms a gene cluster at 94 min on the E. coli genetic map together with the genes coding for two other ribosomal proteins, S6 (rpsF) and S18 (rpsR). Furthermore, the region of the E. coli genetic map containing this cluster was found to be shorter than previously estimated by approximately 2 min.

Bacterial Proteins↗
PubMed1977

A new ribosomal protein locus in Escherichia coli: the gene for protein S6 maps at 97 min.

A mutant of E. coli selected for temperature-sensitive growth on rich medium harbored an altered ribosomal protein S6 (Isono et al., 1976). This mutant was found to possess at least two mutations, one being responsible for the temperature-sensitivity and the other for the S6 alteration. Crosses with various Hfr strains as well as transductions with P 1kc revealed that the former mutation mapped at 98 min and the latter at 97 min. Furthermore, rec A derivatives of this mutant heteromerodiploid for this region possessed both the wild type and themutant forms of S6. Thus it was established that the gene at 97 min was indeed the structural gene for protein S6 (rpsF) and not a gene modifying it.

Bacterial Proteins↗
PubMed1977

Further temperature-sensitive mutants of Escherichia coli with altered ribosomal proteins.

Various alterations in ribosomal proteins were detected in forty-one mutants of E. coli isolated as temperature-sensitive mutants. Out of these, six are new classes of mutants harboring mutations in proteins S3, L5, L7 (L12), L29, L30 and L33. One of them apparently lacks protein L7 of the large subunit. These mutants together with those reported previously (Isono et al., 1976) total one hundred and one ribosomal mutants in thirty different proteins.

Electrophoresis, Agar Gel↗
PubMed1977

Congenital fibromyxoma: report of case.

We have reported the clinical behavior and histochemical patterns of a congenital fibromyxoma in the soft tissues. The tumor was excised without difficulty; one year postoperatively, no recurrence was seen by clinical and radiographic examinations. There were no findings to suggest that the myxoma is a true neoplasm derived from the so-called myxoblast.

Fibroma↗