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R Masuma

Publications and source records attributed to R Masuma.

At least 55 records · Page 3Linked to original sources
PubMed1994

Arohynapenes A and B, new anticoccidial agents produced by Penicillium sp. Taxonomy, fermentation, and structure elucidation.

Penicillium sp. FO-2295, a water isolate, was found to produce a series of new anticoccidial compounds. Two active compounds, designated arohynapenes A and B, were isolated from the fermentation broth of the producing strain by solvent extration and preparative HPLC. Arohynapene A was deduced to be (2E,4E)-5-(5-hydroxy-2,6,8-trimethyl-5,6,7,8-tetrahydronaphtale ne)-2,4- pentadienoic acid, and arohynapene B was (2E,4E)-5-(2-hydroxymethyl-6,8-dimethyl-5,6,7,8-tetrahydronapht alene)-2,4- pentadienoic acid. Arohynapenes inhibited the growth of Eimeria tenella in an in vitro assay using BHK-21 cells as a host. No schizont in the cells was observed at concentrations ranging above 35.0 microM and 7.0 microM for arohynapenes A and B, respectively.

Coccidiostats↗
PubMed1993

Hynapenes A, B and C, new anticoccidial agents produced by Penicillium sp. I. Production, isolation and physico-chemical and biological properties.

Penicillium sp. FO-1611, a soil isolate, was found to produce a series of new anticoccidial compounds. Three active compounds, designated hynapenes A, B and C, were isolated from the fermentation broth of the producing strain by solvent extraction, silica gel column chromatography, gel filtration on Sephadex LH-20 and preparative HPLC. Hynapenes inhibited the growth of Eimeria tenella in an in vitro assay using BHK-21 cells as a host. No schizont in the cells was observed at concentrations ranging above 123 microM, 34.7 microM and 34.7 microM for hynapenes A, B and C, respectively.

Chemical Phenomena↗
PubMed1993

Xanthoquinodins, new anticoccidial agents produced by Humicola sp. Production, isolation and physico-chemical and biological properties.

Humicola sp. FO-888, a soil isolate, was found to produce a series of new anticoccidial compounds. Five active compounds, designated xanthoquinodins A1, A2, A3, B1 and B2 were isolated from the fermentation broth of the producing strain by solvent extraction and HPLC. Xanthoquinodins inhibited the growth of Eimeria tenella in an in vitro assay system using BHK-21 cells as a host. No schizont in the cells was observed at concentrations of 0.02-0.2 micrograms/ml for xanthoquinodins A1, A3, B1 and B2 and at 0.02 micrograms/ml for xanthoquinodin A2.

Animals↗
PubMed1992

Glisoprenins, new inhibitors of acyl-CoA: cholesterol acyltransferase produced by Gliocladium sp. FO-1513. I. Production, isolation and physico-chemical and biological properties.

Gliocladium sp. FO-1513 was found to produce novel inhibitors of acyl-CoA: cholesterol acyltransferase (ACAT). Two active compounds, designated glisoprenins A and B, were isolated from the culture broth of the producing strain by a conventional method. The IC50 values of glisoprenins A and B for ACAT activity were 46 and 61 microM in an enzyme assay using rat liver microsomes, and 1.2 and 0.57 microM in a J774 macrophage assay, respectively.

Animals↗
PubMed1992

New cyclodepsipeptides, enniatins D, E and F produced by Fusarium sp. FO-1305.

New cyclodepsipeptides named enniatins D, E and F were isolated from the culture broth of Fusarium sp. FO-1305 as inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). The respective structures of enniatins D, E and F were determined to be cyclo[D-alpha-hydroxyisovaleryl(D-Hiv)-L-N-methylleucinyl(L- Me-Leu)-D-Hiv-L-N-methylvalinyl(L-Me-Val)-D-Hiv-L-Me-Val], a mixture of cyclo-[D-Hiv-L-Me-Leu-D-Hiv-L-N-methylisoleucinyl(L-Me-Ile)-D-Hiv- L-Me-Val] and cyclo(D-Hiv-L-Me-Ile-D-Hiv-L-Me-Leu-D-Hiv-L-Me-Val), and cyclo(D-Hiv-L-Me-Leu-D-Hiv-L-Me-Ile-D-Hiv-L-Me-Ile) by spectral analyses and chemical degradation. The IC50 values of enniatins D, E and F for ACAT activity in an enzyme assay using rat liver microsomes were calculated to be 87, 57 and 40 microM, respectively.

Animals↗
PubMed1991

Purpactins, new inhibitors of acyl-CoA:cholesterol acyltransferase produced by Penicillium purpurogenum. I. Production, isolation and physico-chemical and biological properties.

Penicillium purpurogenum FO-608, a soil isolate, was found to produce a series of new inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). Three active compounds, designated purpactins, A, B and C, were isolated from the fermentation broth of the producing strain by solvent extraction, silica gel column chromatography and HPLC. Purpactins inhibit ACAT activity in an enzyme assay system using rat liver microsomes with IC50 values of 121 approximately 126 microM. Purpactin A also inhibited cholesterol ester formation in J 774 macrophages, indicating the inhibition of ACAT activity in the living cells by purpactin A.

Animals↗
PubMed1990

Site of regulation of nanaomycin biosynthesis by inorganic phosphate.

The site of regulation of nanaomycin biosynthesis by inorganic phosphate was studied with washed cells previously grown in a chemically defined medium containing a high- or low-phosphate concentration. The former mycelia produced only about one-tenth the amount of nanaomycin A from acetate as did the latter mycelia. On the other hand, the bioconversions of nanaomycin D to A and nanaomycin A to E were only slightly affected. It is suggested that the site of regulation of nanaomycin biosynthesis by inorganic phosphate lies within steps between acetate and nanaomycin D.

Anti-Bacterial Agents↗
PubMed1987

Jietacins A and B, new nematocidal antibiotics from a Streptomyces sp. Taxonomy, isolation, and physico-chemical and biological properties.

Jietacins A and B, new azoxy antibiotics, were isolated from the culture broth of a streptomycete. The antibiotics have the molecular formulae of C18H34N2O2 and C19H36N2O2, respectively. Both possess an azoxy group. They have potent activity against the pine wood nematode, Bursaphelenchus lignicolus, and are weakly active against some fungi.

Animals↗
PubMed1986

Ahpatinins, new acid protease inhibitors containing 4-amino-3-hydroxy-5-phenylpentanoic acid.

A soil isolate, Streptomyces sp. WK-142, was found to produce new acid protease inhibitors, ahpatinins A, B, D, E, F and G active against pepsin and renin. Ahpatinin C was found to be identical with pepstatin A. The structure determinations were based on mass spectral data. Four of the compounds contain the unusual amino acid, 4-amino-3-hydroxy-5-phenylpentanoic acid as a building component.

Amino Acids↗
PubMed1986

Clostomicins, new antibiotics produced by Micromonospora echinospora subsp. armeniaca subsp. nov. I. Production, isolation, and physico-chemical and biological properties.

A soil isolate named as Micromonospora echinospora subsp. armeniaca subsp. nov. KMR-593 was found to produce at least five related antibiotics, clostomicins, active against Gram-positive bacteria including anaerobes. From the physico-chemical properties, one of these components was identified with lipiarmycin and others were found to be new antibiotics. Each component includes two chlorine atoms and the molecular weights of A and B2, C, and D are 1,058, 1,042 and 1,056, respectively. The structural differences were characterized by NMR analyses.

Aminoglycosides↗
PubMed1986

Production of nanaomycin and other antibiotics by phosphate-depressed fermentation using phosphate-trapping agents.

Nanaomycin production by Streptomyces rosa subsp. notoensis in complex media was inhibited by exogenously supplied inorganic phosphate. The inhibition was reversed by phosphate-trapping agents such as allophane and aluminum oxide. Under such condition nanaomycin production increased to the control level, and the phosphate content dropped down to the unsupplemented level. When allophane was added to conventional complex media containing nutrient-derived inorganic phosphate, the production of nanaomycin and several other antibiotics, which are subject to phosphate regulation, was enhanced several fold with the simultaneous reduction of free phosphate. The term "phosphate-depressed fermentation" is proposed for this technique.

Anti-Bacterial Agents↗
PubMed1986

Mechanism of nitrogen regulation of protylonolide biosynthesis in Streptomyces fradiae.

A resting cell system was used to study the sites of inhibition by NH4+ of protylonolide biosynthesis by a blocked mutant, strain 261, of Streptomyces fradiae. With 14C-labeled succinate or valine as an exogenous substrate, labeled protylonolide formation by high-NH4+ grown mycelia of strain 261 was lower than by low-NH4+ grown mycelia. When 14C-labeled palmitate or acetate + labeled propionate + butyrate were used as the substrates, protylonolide production by mycelia grown under the two NH4+ conditions was nearly at the same rates. It is suggested that the metabolism of succinate and valine to lower fatty acid precursors is subject to NH4+ regulation, whereas condensation of acid precursors and related steps leading to protylonolide are insensitive to NH4+ concentration.

Carbon Radioisotopes↗
PubMed1984

Control of ammonium ion level for efficient nanaomycin production.

The addition of a small amount of NH4+ to a complex medium increased nanaomycin production by Streptomyces rosa subsp. notoensis OS-3966. The best NH4+ donor for nanaomycin production was NH4+-saturated natural zeolite, with which the maximum titer of nanaomycin E was 760 micrograms/ml, about four fold higher than the control titer. In contrast, lowering NH4+ levels by adding NH4+-trapping agents such as untreated natural zeolite reduced antibiotic production.

Aluminum Silicates↗
PubMed1984

Effect of ammonium ion, inorganic phosphate and amino acids on the biosynthesis of protylonolide, a precursor of tylosin aglycone.

The production of tylosin by Streptomyces fradiae KA-427 in a defined medium was inhibited by ammonium ions and by inorganic phosphate. The production of protylonolide, an early lactonic intermediate of tylosin biosynthesis with the same carbon skeleton as tylosin aglycone, by a mutant of strain KA-427 was also reduced by these two kinds of ions. In contrast, the bioconversion of protylonolide to tylosin by another mutant was less susceptible to ammonium ions but was sensitive to inorganic phosphate. The addition of protylonolide to a culture of S. fradiae KA-427 increased the tylosin yield, suggesting that aglycone synthesis is limiting under the conditions used. When L-valine, L-leucine, L-isoleucine, L-threonine, or the corresponding 2-keto acid was added to the culture medium, the protylonolide titer increased. The addition of [14C]valine gave rise to [14C]protylonolide. 13C NMR spectroscopic analysis revealed that iso-butyrate, which is a valine metabolite, was incorporated into protylonolide at the carbons known to originate from propionate and n-butyrate. Taking account of these findings, the regulation of tylosin biosynthesis in S. fradiae by ammonium ion is discussed in relation to amino acid metabolism.

Amino Acids↗