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K Mihara

Publications and source records attributed to K Mihara.

At least 217 records · Page 12Linked to original sources
PubMed1983

Induction at high frequency of a unique phenotypic class of Bacillus subtilis mutants by methylxanthines.

Caffeine and theophylline are mutagenic at high concentration in the B. subtilis multigene sporulation test for mutagens; caffeine is a stronger mutagen than theophylline in this test. An unusually high fraction of the mutant colonies appear to be phenotypically identical, as judged by colonial morphology and microscopic appearance of the vegetative cells. These mutants do not bring about the pH increase normally associated with sporulation of B. subtilis; such behavior is frequently associated with lack of a functional tricarboxylic acid (TCA) cycle, essential for normal sporulation of this species. Similar mutants have not been noted in the course of screening a variety of well-known mutagens, including acriflavine. Caffeine is maximally effective in inducing these mutants about 10 min after germination commences. Adenosine greatly reduces the ability of caffeine to induce these mutants.

Acriflavine↗
PubMed1982

[CT of thymoma].

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Adult↗
PubMed1982

Rat liver L-glutamate dehydrogenase, malate dehydrogenase, D-beta-hydroxybutyrate dehydrogenase, and sulfite oxidase are each synthesized as larger precursors by cytoplasmic free polysomes.

Four cytoplasmically synthesized rat liver mitochondrial enzymes, located either as soluble enzymes in the mitochondrial matrix (L-glutamate dehydrogenase and malate dehydrogenase or in the intermembrane space (sulfite oxidase) or as an integral membrane protein located on the matrix face of the inner mitochondrial membrane (D-beta-hydroxybutyrate dehydrogenase), were all shown to be synthesized as precursors larger than their mature counterparts by 1000-6000 daltons. These larger forms were detected in vitro, in a cell-free protein synthesizing system programmed with either total rat liver RNA or with RNA isolated from free polysomes or with free polysomes, and in vivo, in the two cases that were investigated (L-glutamate dehydrogenase and D-beta-hydroxybutyrate dehydrogenase), by pulse labeling of Buffalo rat liver cells in culture. The intracellular site of synthesis of all four mitochondrial enzymes was shown to be primarily on free polysomes and not on membrane-bound polysomes.

Animals↗
PubMed1982

In vitro synthesis and integration into mitochondria of porin, a major protein of the outer mitochondrial membrane of Saccharomyces cerevisiae.

We have isolated an outer mitochondrial membrane (OMM) fraction from baker's yeast. Saccharomyces cerevisiae, that possesses porin activity and contains a major polypeptide of 29,000 daltons. By analogy to similar data for an OMM fraction from rat liver and mung bean [Zalman, L. S., Nikaido, N. & Kagawa, Y. (1980) J. Biol. Chem. 255, 1771-1774], the 29,000-dalton polypeptide of the isolated yeast OMM fraction has been tentatively identified as porin. Evidence to substantiate this identification was provided by the finding that both the porin activity and the 29,000-dalton polypeptide were entirely resistant when the OMM fraction was exposed to trypsin digestion, with the 29,000-dalton polypeptide being virtually the only polypeptide in the OMM fraction to be unaffected by trypsin digestion. There was no protection when trypsin digestion was carried out in the presence of detergent. Using monospecific antibodies, we have shown that yeast porin is apparently not synthesized as a larger precursor in a cell-free translation system. In vitro-synthesized porin could not be integrated into dog pancreas microsomal vesicles or into an isolated OMM fraction from yeast, either co- or posttranslationally. In vitro-synthesized porin, however, could be integrated posttranslationally into whole isolated mitochondria. This membrane specificity suggests that integration does not proceed by unassisted partitioning. The integration of porin into whole mitochondria occurred with fidelity by the criterion of its resistance to trypsin. Moreover, integration was not inhibited in the presence of the protonophore carbonyl cyanide m-chlorophenyl-hydrazone whereas translocation into the mitochondrial matrix of the in vitro-synthesized gamma subunit of F1-ATPase was inhibited.

Cell-Free System↗
PubMed1982

Angioma in the paraspinal muscles complicated by spinal epidural hematoma. Case report.

This case of angioma in the paraspinal muscles with extension into the epidural tissue was complicated by epidural hematoma in the thoracolumbar region. The hemorrhage was caused by rupture of the part of the angioma lying in the epidural tissue. A spinal bruit was of great value in diagnosing the angioma. Percutaneous embolization of the feeding arteries of the angioma reduced bleeding during surgery and contributed to successful surgical treatment.

Epidural Space↗
PubMed1980

Urinary oligosaccharides of mannosidosis.

Nine oligosaccharide fractions were purified from the urine of mannosidosis patients by Bio-Gel P-4 column chromatography, paper chromatography, and paper electrophoresis. Studies using exoglycosidase digestion, methylation analysis, periodate oxidation, and acetolysis revealed that most of the fractions were mixtures of two or three isomeric oligosaccharides. The structures of a total of 16 oligosaccharides were elucidated to be as follows: (formula: see text).

Adolescent↗