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Biomedical subjects

R Oiwa

Publications and source records attributed to R Oiwa.

36 records · Page 2Linked to original sources
PubMed1979

Avermectins, new family of potent anthelmintic agents: producing organism and fermentation.

The avermectins are a complex of chemically related agents which exhibit extraordinarily potent anthelmintic activity. They are produced by a novel species of actinomycete, NRRL 8165, which we have named Streptomyces avermitilis. The morphological and cultural characteristics which differentiate the producing organism from other species are described. The avermectins have been identified as a series of macrocyclic lactone derivatives which, in contrast to the macrolide or polyene antibiotics, lack significant antibacterial or antifungal activity. The avermectin complex is fully active against the gastrointestinal nematode Nematospiroides dubius when fed to infected mice for 6 days at 0.0002% of the diet. Fermentation development, including medium modification and strain selection, resulted in increasing the broth yields from 9 to 500 mug/ml.

Anthelmintics↗
PubMed1979

Studies on bacterial cell wall inhibitors. VI. Screening method for the specific inhibitors of peptidoglycan synthesis.

A screening method was established for selecting new specific inhibitors of bacterial cell wall peptidoglycan synthesis. In the primary test, culture broths of soil isolates were selected based on relative microbial activity. A culture, to be retained, must be active against Bacillus subtilis and lack activities against Acholeplasma laidawii. In the secondary test, inhibitors of bacterial cell wall synthesis were identified by their ability to prevent the incorporation of meso-[3H]diaminopimelic acid but not to prevent the incorporation of L-[4C]leucine into the acid-insoluble macromolecular fraction of growing cells of Bacillus sp. ATCC 21206 (Dpm-). As the tertiary test, inhibitors with molecular weights under 1,000 were selected by passage through a Diaflo UM-2 membrane. By this screening procedure, six known antibiotics and one new one were picked out from ten thousand soil isolates.

Acholeplasma laidlawii↗
PubMed1979

Studies on bacterial cell wall inhibitors. VII. Azureomycins A and B, new antibiotics produced by Pseudonocardia azurea nov. sp. Taxonomy of the producing organism, isolation, characterization and biological properties.

Two new basic water-soluble antibiotics, azureomycins A and B, were isolated from the culture broth of an actinomycete, strain AM-3696, designated as Pseudonocardia azurea nov. sp. The antibiotics exhibit moderate antimicrobial activities against Gram-positive bacteria including penicillin-resistant Staphylococcus, Mycobacterium and Clostridium. They inhibit the synthesis of bacterial cell wall peptidoglycan.

Actinomycetales↗
PubMed1979

Studies on bacterial cell wall inhibitors. VIII. Mode of action of a new antibiotic, azureomycin B, in Bacillus cereus T.

Azureomycin B, a new antibiotic which contains sugar, amino acid and phenol moieties and inhibits Gram-positive bacteria, was found to be a specific inhibitor of peptidoglycan synthesis in bacteria. The antibiotic lysed growing cells of Bacillus cereus T at a concentration of 10 micrograms/ml but did not affect resting cells. Microscopical observation revealed swelling and lysis of the bacterial rods when treated with azureomycin B. The incorporation of [3H]diaminopimelic acid or [14C]glucosamine into acid-insoluble fraction of growing cells of Bacillus cereus T was strongly inhibited in the presence of azureomycin B, but that of [14C]leucine, [3H]thymidine or [3H]uridine were not, at least until 5 minutes after the beginning of the incubation. The antibiotic caused accumulation of a nucleotide precursor in the cells which was identified as UDP-MurNAc-L-Ala-D-Glu-meso-Dpm-D-Ala-D-Ala. Thus the site of action was suggested to lie between this nucleotide and peptidoglycan in the pathway of peptidoglycan synthesis.

Anti-Bacterial Agents↗
PubMed1979

The site of inhibition of cell wall synthesis by 3-amino-3-deoxy-D-glucose in Staphylococcus aureus.

The inhibition of growth and cell wall synthesis by 3-amino-3-deoxy-D-glucose (3-AG), which is known to be one of the constituents of the kanamycin molecule and a metabolite of Bacillus sp., was almost completely overcome by glucosamine and N-acetylglucosamine in Staphylococcus aureus but scarcely affected by D-glucose and D-fructose. The antibiotic did not inhibit the incorporation of [14C]glucosamine and [3H]N-acetylglucosamine into the acid-insoluble fraction, but rather enhanced the incorporation of [14C]glucosamine. On the other hand, it inhibited the incorporation of D-[14C]fructose into the cell wall fraction but hardly affected the incorporation of D-[14C]fructose into the acid-insoluble fraction in the presence of pencillin G. Based on these results, it is suggested that the site of primary action of 3-AG is the formation of glucosamine-6-phosphate from D-fructose-6-phosphate, which is catalyzed by glucosamine synthetase [EC 2.6.1.16].

Acetylglucosamine↗
PubMed1978

Aurantinin, a new antibiotic of bacterial origin.

A new polyene class antibiotic, aurantinin (KM-214), was isolated from the fermentation broth of Bacillus aurantinus MASUMA and OMURA sp. nov. The substance is a conjugated triene with a molecular weight of 618 and molecular formula C35H54O9, and melts at 139 approximately 140 degrees C. The antibiotic is active in vitro against Gram-positive bacteria, but not against yeast and fungi.

Animals↗
PubMed1978

Production of deoxyfrenolicin and a new antibiotic, frenolicin B by Streptomyces roseofulvus strain AM-3867.

Two antibiotics of frenolicin group, antibiotic AM-3867 I and II were isolated from the fermentation broth of Streptomyces roseofulvus strain No. AM-3867, a soil isolate. The former was a new antibiotic designated as frenolicin B and its structure containing gamma-lactone was determined, while the latter was identified as deoxyfrenolicin having been chemically prepared from frenolicin.

Anti-Bacterial Agents↗
PubMed1977

Studies on bacterial cell wall inhibitors. III. 3-amino-3-deoxy-D-glucose, an inhibitor of bacterial cell wall synthesis.

It was shown that 3-amino-3-deoxy-D-glucose, one of the constituents of the kanamycin molecule and a metabolite of Bacillus sp., inhibits the bacterial synthesis of cell wall. The antibiotic (100 microgram/ml) significantly inhibits the growth of Staphylococcus aureus FDA 209P as well as the incorporation of DL-[14C]alanine into the acid-insoluble macromolecular fraction of its growing cells in the presence of chloramphenicol (100 microgram/ml). In contrast, the antibiotic does not affect the incorporation of [3H]thymidine, [3H]uridine and L-[14C]leucine. The other constituents of kanamycin, 6-amino-6-deoxy-D-glucose and deoxystreptamine do not inhibit the synthesis of bacterial cell wall peptidoglycan.

Alanine↗
PubMed1977

New antitumor antibiotics, OS-4742 A1, A2, B1 and B2 produced by a strain of Streptomyces.

New antibiotics, OS-4742 A1, A2, B1 and B2, were isolated from the culture broth of the strain OS-4742, which was designated as Streptomyces matensis subsp. vineus. These compounds have anthracycline chromophores and sugar moieties, but do not contain nitrogen. They possess antimicrobial activities against Gram-positive bacteria and antitumor activities against S-180 solid tumor on mice.

Animals↗
PubMed1976

A new antibiotic,, asukamycin, produced by Streptomyces.

Asukamycin, a new antibiotic, has been isolated from the culture broth of a streptomycete designated as Streptomyces nodosus subsp. asukaensis. The antibiotic inhibits the growth of Gram-positive bacteria including Nocardia asteroides. The empirical formula of antibiotic asukamycin has been proposed as C29H22N2O9 (M.W. 542). An acute toxicity of the antibiotic in mice is LD50 48.5 mg/kg by intraperitoneal injection and it has no effect on mice when it was administered by 450 mg/kg per os.

Animals↗
PubMed1975

Nanaomycins, new antibiotics produced by a strain of Streptomyces. I. Taxonomy, isolation, characterization and biological properties.

Nanomycins are new antibiotics produced by the strain OS-3966 which was designated Streptomyces rosa var. notoensis. Nanomycins A and B were isolated from the culture filtrate by extraction with organic solvent and silica gel chromatography. The physical and chemical properties suggest that nanaomycins A and B are quinone-related compounds having the molecular formulae, C16H14O6 and C16H16O7, respectively. Nanaomycins A and B inhibit mainly mycoplasmas, fungi and Gram-positive bacteria. The acute toxicities (LD50, ip) of nanaomycins A and B in mice are 28.2 and 169 mg/kg, respectively.

Animals↗