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Biomedical subjects

M Kuroda

Publications and source records attributed to M Kuroda.

At least 523 records · Page 29Linked to original sources
PubMed1977

Time-dependent, irreversible inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase by the antibiotic citrinin.

The inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase by citrinin, an antibiotic, has been studied. The inhibition was the mixed type with respect to 3-hydroxy-3-methylglutaryl-CoA and non-competitive with respect to NADPH. When the enzyme was preincubated with citrinin prior to enzyme assay, however, it caused a time-dependent, irreversible inhibition, possibly by binding to a site distinct from the active center on the enzyme protein.

Alcohol Oxidoreductases↗
PubMed1977

Inhibition of sterol synthesis by citrinin in a cell-free system from rat liver and yeast.

Citrinin, a fungal metabolite known as an antibiotic, strongly inhibited the labeled acetate incorporation into nonsaponifiable lipids by a cell-free system from rat liver but not the labeled mevalonate incorporation. Of the enzymes involved in cholesterol synthesis, two enzymes, acetoacetyl-CoA thiolase (EC 2.3.1.9) and 3-hydroxy-3-methylglutaryl-CoA reductase (EC 1.1.1.34), were specifically inhibited by the antibiotic. The concentration required for 50% inhibition was 0.2 mM for the former enzyme and 0.5 mM for the latter. Essentially the same results were obtained with a cell-free system from yeast although higher concentrations of the antibiotic were required for inhibition.

Acetyl-CoA C-Acetyltransferase↗
PubMed1977

Control of tryptophan synthetase amplified by varying the numbers of composite plasmids in Escherichia coli cells.

Using pSC101, RSF1010, RSF2124 and RP4 plasmids as vectors and bacteriophage lambdatrpD-A60-3 DNA as a source of the Escherichia coli whole tryptophan operon, composite plasmids of pSC101-trp, RSF1010-trp, RSF2124-trp and RP4-trp were constructed in vitro with EcoRI restriction endonuclease and DNA ligase. Each composite plasmid could be maintained stably in E. coli cells. The copy number of pSC101-trp, RSF1010-trp, RSF2124-trp and RP4-trp were 4.2, 11.2, 11.9 and 1.6 per chromosome respectively. The tryptophan synthetase activities in cells containing pSC101-trp, RSF1010-trp, RSF2124-trp aand RP4-trp plasmid were found to be 2.1, 6.0, 5.0 and 2.5 times compared with the level in chromosomal trp+ cells when they were grown in a minimal medium. By partial derepression with indolylacrylic acid, the enzyme levels were elevated to 10.1, 16.3, 15.3, 12.3 times, respectively, that of the control cells. The tryptophan synthetase activities did not increase in proportion to the copy number of the plasmids, but were strongly affected by the repression system of host cells.

DNA Replication↗
PubMed1977

beta-actinin, a regulatory protein of muscle. Purification, characterization and function.

beta-Actinin, a minor regulatory protein of muscle, was purified from skeletal muscles of rabbit and chicken by DEAE-Sephadex chromatography. beta-Actinin consisted of two subunits, beta I and betaII, with chain weights of 37,000 and 34,000 daltons, respectively. The amino acid compositions were similar, though not identical. It appears that each of the two subunits is associated in solution. beta-Actinin had the following effects on actin: (1) inhibition of reassociation of F-actin fragments; (2) inhibition of network formation of F-actin; (3) inhibition of growth of F-actin fragments; (4) retardation of depolymerization of F-actin and (5) acceleration of polymerization of G-actin. All these actions of beta-actinin can be explained in terms of action as an "ending factor". Experimental evidence favored the view that beta-actinin is bound to one end of the F-actin filament, namely to the end opposite to the direction of polymerization. Fluorescence-labeled anti-beta-actinin stained the middle portion of the A band of myofibrils. Based on the finding that the stain was unchanged on removal of myosin, it is suggested that beta-actinin is located at the free ends of the I filaments of myofibrils. Thus is seems likely that beta-actinin functions as an ending factor for actin filaments.

Actinin↗
PubMed1977

Isolation and characterization of four plasmids from Bacillus subtilis.

Nineteen Bacillus subtilis isolates obtained from type culture collections were examined for the presence of covalently closed circular duplex deoxyribonucleic acid molecules by the technique of cesium chloride-ethidium bromide density gradient centrifugation. Four of the 19 strains tested carried covalently closed circular molecules. Two of these strains (IFO3022, IFO3215) harbored a similar plasmid with a molecular weight of 5.4 X 10(6). The other two strains (IAM1232, IAM1261) carried 4.9 C 10(6)-and 5.3 X 10(6)-dalton plasmids, respectively. These plasmid-harboring strains did not show phenotypic traits such as antibiotic resistance orbacteriocin production. The plasmid deoxyribonucleic acids were digested by three restriction endonucleases, EcoRI, HindIII, and BamNI, and were classified into three different types from their electrophoretic patterns in agarose gels.

Anti-Bacterial Agents↗
PubMed1977

Clinical evaluation of pivmecillinam in intractable urinary-tract infections with complications. A comparative study with amoxicillin by a randomized double-blind technique.

A comparative study was made by the double-blind technique in order to make clear the usefulness of pivmecillinam in the treatment of intractable complicated urinary-tract infections using amoxicillin as a reference drug. Pivmecillinam was given in dosage of 400 mg (potency) per day which was one-fifth the dose of amoxicillin 2,000 mg (potency) per day. In global judgement, pivmecillinam was found superior to amoxicillin. It showed a "significant" superiority over amoxicillin for the treatment of, among others, the urinary-tract infections after prostatectomy, which are intractable diseases. When evaluated by symptoms, pivmecillinam improved bacteriuria "significantly" better than amoxicillin. When seen by causative organisms, the pivmecillinam treatment was "significantly" superior to the amoxicillin treatment against E. coli infections. Pivmecillinam was active against amoxicillin-resistant E. coli. Incidence of adverse reactions was less frequent with pivmecillinam than with amoxicillin. These results indicate that pivmecillinam is a drug of high usefulness for the treatment of intractable complicated urinary-tract infections when evaluated using amoxicillin as a reference drug.

Adult↗