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Biomedical subjects

H Imanaka

Publications and source records attributed to H Imanaka.

135 records · Page 8Linked to original sources
PubMed1980

Biosynthesis of bicyclomycin. II. Biosynthetic conditions and incorporation of radioactive precursors into bicyclomycin by washed mycelium.

The biosynthesis of bicyclomycin by Streptomyces sapporonensis was studied using suspensions of washed mycelium. Nicotinamide and Fe2+ were found to be essential cofactors in the biosynthesis. Production of bicyclomycin was enhanced most effectively in the presence of equal moles of L-leucine and L-isoleucine, which in experiments with radioactively labeled compounds were found to be incorporated into bicyclomycin at equivalent rates. These facts strongly suggest that bicyclomycin biosynthesis involves coupling of equal moles of these two amino acids.

Amino Acids↗
PubMed1980

Studies on new phosphonic acid antibiotics. II. Taxonomic studies on producing organisms of the phosphonic acid and related compounds.

A new species of Streptomyces which produces a new cell wall-inhibitory antibiotic, FR-900098 containing phosphonic acid in its molecule, is named and described. The species name proposed, Streptomyces rubellomurinus, refers to the aerial mass color. Streptomyces rubellomurinus subsp. indigoferus also produces FR-900098 and the related compound FR-33289. FR-900098 related compounds, FR-32863 and FR-31564 are produced by Streptomyces lavendulae.

Anti-Bacterial Agents↗
PubMed1976

Mechanism of action of bicyclomycin.

Microscopic examination of cultures of Escherichia coli exposed to bicyclomycin revelaed elongated or spheroplast-like cells. At the lethal level, bicyclomycin was shown to inhibit the synthesis of RNA and protein in the growing cells of E. coli 15 THU, whereas DNA and lipid synthesis were not significantly affected. However, the antibiotic did not block RNA and protein synthesis in vitro. Bicyclomycin was observed to inhibit the synthesis of envelope proteins more markedly than that of cytoplasmic proteins. The synthesis of two major envelope proteins was more sensetive to bicyclomycin than that of the other envelope proteins. One (peak I), which was inhibited to the greatest extent, seemed to be identical with a bound form of lipoprotein, and the other (peak V) with a free form of lipoprotein. Bicyclomycin exhibited inhibitory effects on the exclusive biosynthesis of the lipoprotein in histidine-starved cells of E. coli 15 THU. The biosynthesis of the bound form of lipoprotein was more profoundly inhibited by bicyclomycin than that of the free form. These results indicate that the primary action of bicyclomycin may be due to the interference with the biosynthesis of lipoprotein, and its assembly to peptidoglycan.

Anti-Bacterial Agents↗
PubMed1976

Enterocin, a new antibiotic taxonomy, isolation and characterization.

Enterocin is a new antibiotic isolated from cultures of two strains of Streptomyces, which were given the names Streptomyces candidus var. enterostaticus WS-8096 and variant M-127 of Streptomyces viridochromogenes. Its elementary analysis and mass spectroscopic measurement suggest the molecular formula is C22H20010. The ultraviolet absorption gave two maximal peaks at 250 nm and 283 nm in methanol. Enterocin has static activities against gram-positive and gram-negative bacteria and no activity against fungi and yeast.

Animals↗
PubMed1967

Synchronous growth and sporulation of Bacillus megaterium.

Filtration of late log-phase cultures of Bacillus megaterium ATCC 19213 grown on defined sucrose salts medium (SS) or SS plus glutamate medium (SSG) through nine layers of Whatman no. 40 filter paper in a fritted-glass disc Büchner funnel resulted in filtrates containing cells which showed synchronous growth and proceeded to sporulation. SS cells completed one synchronous division after filtration; sporulation ensued after the cessation of growth. SSG cells completed two synchronous divisions and sporulation occurred during the second division. A high degree of synchrony of vegetative growth of SSG cells was evident by the stepwise pattern of growth, by the doubling of cell numbers at each division, the high division index, and by the rapid formation of sporulation cell types and homogeneity of cell types in the filtered cultures when compared with asynchronous cultures. Because the described system gives both good growth and sporulation synchrony, the method should be useful in delineating early events in sporulation and their regulation.

Bacillus megaterium↗