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Biomedical subjects

H Imanaka

Publications and source records attributed to H Imanaka.

At least 127 records · Page 7Linked to original sources
PubMed1982

Studies on a new immunoactive peptide, FK-156. II. Fermentation, extraction and chemical and biological characterization.

An interesting immunoactive peptide, FK-156, has been isolated from the fermentation broth of Streptomyces olivaceogriseus sp. nov. and Streptomyces violaceus. The compound was purified by column chromatography with activated carbon, ion exchange Sephadex and cellulose powder. FK-156, obtained as white powder, exhibits a wide variety of immunostimulatory activity in vivo and in vitro with experimental animals. Pretreatment of mice or rats with this peptide protected the animals against lethal infection with Escherichia coli and resulted in prolongation of life span of tumor bearing animals.

Adjuvants, Immunologic↗
PubMed1982

Studies on new vasodilators, WS-1228 A and B. I. Discovery, taxonomy, isolation and characterization.

New vasodilators, designated WS-1228 A and B have been discovered in the culture filtrate of a strain of Streptomyces aureofaciens. The active compounds were purified by column chromatography with Diaion HP-20 and silica gel, and finally separated from each other by high performance liquid chromatography. They were obtained as pale yellow crystals and their molecular formulae were both C11H17N3O.

Animals↗
PubMed1981

A short-term in vitro assay for promoter substances using human lymphoblastoid cells latently infected with Epstein-Barr virus.

We designed a short-term in vitro assay for detecting tumor promoters, utilizing the activation of Epstein-Barr virus (EBV) expression in EBV genome-carrying human lymphoblastoid cells. This system is composed of EBV-non-producer Raji cells as the indicator, n-butyrate as the EBV-inducer, and the test substance. After addition of the latter 2 components to the culture medium, the cells are cultivated for 48 h at 37 degrees C and the ratio of EBV early antigen (EA)-expressing cells was assessed using immunofluorescence. This assay system allows for a rapid detection of the activity of the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and its related compounds and also of the Euphorbiaceae plant extracts containing such active principles. Among several microbial products tested, teleocidin, an indole-alkaloid produced by a Streptomyces species, was also detected and had an activity level comparable to that of TPA. Other promoters, such as anthralin, phenol, Tween 60 and 80 and the carcinogenic ("initiator") substances including benzopyrene, did not react with the system. The test is simple to perform, reproducible and should be applicable for mass-screening of promoter substances in the environment.

Carcinogens↗
PubMed1980

Streptomyces auranticolor Sp. Nov., a new anticoccidial antibiotics producer.

A new species of Streptomyces is described and designated Streptomyces auranticolor (FERM-P No. 5365) which produces new anticoccidial antibiotics, designated as WS-5995 A and WS-5995 B. The organism is characterized by gray spore mass color, spiral spore chain with smooth spores, non-chromogenic reaction, soluble pigment, and carbon utilization characteristics. It differs from previously described streptomycetes on the basis of carbon utilization, and pigment production.

Coccidiostats↗
PubMed1980

New anticoccidial antibiotics, WS-5995 A and B. I. Isolation and characterization.

WS-5995 A, B and C are produced by a new strain of Streptomyces designated Streptomyces auranticolor. These antibiotics were purified by solvent extraction followed by chromatography on silica gel and then crystallized. WS-5995 A (C19H12O6, m.p., 289 approximately 291 degrees C) and WS-5995 B (C19H14O6, sublimation at 300 degrees C) protect chickens from infection with Eimeria tenella, a species of coccidia, which produces morbidity or mortality in chickens. WS-5995 C (C19H14O 7, m.p. 288 approximately 290 degrees C), a biologically inactive component, was found to be converted to WS-5995 A on treatment with trifluoroacetic anhydride.

Animals↗
PubMed1980

FR-900130, a novel amino acid antibiotic. I. Discovery, taxonomy, isolation, and properties.

A new antibiotic, designated FR-900130, has been discovered in the culture filtrate of Streptomyces. The producing organism has been identified as Streptomyces catenulae. The antibiotic was purified by adsorption onto Duolite C-20, passage through Amberlite IRC-50, final purification and desalting on Sephadex G-25. It shows antimicrobial activity against Gram-positive bacteria and synergy with D-cycloserine. The antibiotic is very labile in alkaline solution above pH 8.0 and decomposed during lyophilization or solvent precipitation. It was converted to an acetyl derivative and the biological properties of the derivative were examined.

Acetylation↗
PubMed1980

Studies on new phosphonic acid antibiotics. I. FR-900098, isolation and characterization.

A strain of Streptomyces, isolated from a soil sample and identified as Streptomyces rubellomurinus sp. nov., has been found to produce FR-900098, an interesting new antibiotic containing phosphorus in its molecule. The antibiotic, obtained as colorless crystals, was shown to inhibit a wide variety of Gram-negative bacteria including Pseudomonas, Proteus, and Escherichia coli. Its antibacterial action involves interference with bacterial cell wall synthesis as evidenced by the fact that it causes spheroplast formation by susceptible cells.

Anti-Bacterial Agents↗
PubMed1980

Studies on new phosphonic acid antibiotics. III. Isolation and characterization of FR-31564, FR-32863 and FR-33289.

Three phosphonic acid antibiotics were found to be produced in the fermentation broths of Streptomyces. FR-31564 and FR-32863 were produced by Streptomyces lavendulae. FR-33289 was produced by a strain of Streptomyces, identified as Streptomyces rubellomurinus subsp. indigoferus. They are distinct from, but resemble FR-900098 which was reported in our preceding paper, in their chemical and biological characteristics.

Anti-Bacterial Agents↗
PubMed1980

FR-900148, a new antibiotic. I. Taxonomy, fermentation, isolation and characterization.

A strain of Streptomyces, isolated from a soil sample and identified as Streptomyces xanthocidicus, has been found to produce FR-900148, a new antibiotic containing chlorine in its molecule. The antibiotic inhibits both Gram-positive and negative bacteria. However, it is not effective against wild type of Pseudomonas aerguinosa. Its antibacterial action is considered to result from cell wall synthesis inhibition since it causes spheroplast formation from susceptible cells.

Anti-Bacterial Agents↗
PubMed1980

FR-900137, a new antibiotic. I. Taxonomy and fermentation of the organism, and isolation and characterization of the antibiotic.

A strain of Streptomyces, isolated from a soild sample and identified as Streptomyces unzenensis sp. nov. has been found to produce FR-900137, an interesting new antibiotic, containing phosphorus in its molecule. The antibiotic, obtained as white powder, was shown to inhibit a wide variety of Gram-positive and Gram-negative bacteria except Pseudomonas aeruginosa.

Animals↗
PubMed1980

Biosynthesis of bicyclomycin. I. Appearance of aerial mycelia negative strains (am-).

The degeneration of bicyclomycin-producing strains of Streptomyces sapporonensis resulted in sharply depressed bicyclomycin formation in a large scale fermentation. Degenerated strains, whose productivities were only 1/30 to 1/100 of normal strains, could not form aerial mycelia on glucose-BENNETT's agar; they were aerial mycelia negative strains (am-). Repeated transfers of culture, treatment of mycelia with acriflavin, mechanical agitation shock on mycelia or higher growth conditions stimulated the degeneration of producing strains, suggesting the involvement of extrachromosomal elements or plasmids in biosynthesis of bicyclomycin. Shake flask fermentation inoculated with a mixture of a normal high-producing strain and a degenerated low-producing strain resulted in sharply depressed bicyclomycin formation in proportion to the increase of low-producing strain added. It appears that the low-producing strain outgrew the high-producing strain.

Acriflavine↗