Search PubMed⌕ Search

Biomedical subjects

H Fujiki

Publications and source records attributed to H Fujiki.

At least 289 records · Page 16Linked to original sources
PubMed1979

Phosphoethanolamine as a growth factor of a mammary carcinoma cell line of rat.

We have identified phosphoethanolamine as the pituitary-derived growth-promoting material that specifically stimulates the rat mammary carcinoma cell line 64-24. We have been studying the growth characteristics of the 64-24 cell line, which was isolated from a highly hormone-dependent tumor and which retains in culture many characteristics of the original tumor. Previously, crude bovine pituitary extract was shown to contain a significant amount of growth-stimulating activity for these cells, and a growth factor from this extract was purified to homogeneity. This report describes the identification of the growth factor as phosphoethanolamine. Further, the biological activity of phosphoethanolamine was found to be virtually identical to that of the purified growth factor. A possible role of phosphoethanolamine in the growth of mammary tumor cells as well as of normal mammary epithelial cells and other tissues is discussed.

Animals↗
PubMed1979

Induction of erythroid differentiation of murine erythroleukemia cells by nicotinamide and related compounds.

Nicotinamide and its analogues were evaluated for their activity as inducers of differentiation of murine erythroleukemia cells in culture. N'-Methylnicotinamide was the most effective of the compounds tested; at its optimal concentration it was more effective than dimethyl sulfoxide. With 8-10 mM N'-methylnicotinamide, almost all the cells contained hemoglobin (benzidine-reactive) after a 60-hr culture. Commitment to differentiate, assayed by transfer of the cells to semisolid medium without inducers, occurred much earlier and was more extensive with N'-methylnicotinamide than that with dimethyl sulfoxide or nicotinamide. Increase in globin mRNA was greater in the cells cultured with N'-methylnicotinamide than in cells cultured with dimethyl sulfoxide or nicotinamide. The relationship between the inducing activities of nicotinamide analogues and their effect on poly(ADP-ribose) polymerase in vitro was studied. All the compounds studied that had strong inhibitory effects on poly(ADP-ribose) polymerase in vitro induced differentiation of erythroleukemia cells in culture. This property is not a prerequisite of inducers; N'-methylnicotinamide did not inhibit the enzyme in vitro.

Animals↗
PubMed1978

The effect of norharman on the metabolism of benzo[alpha]pyrene by rat-liver microsomes in vitro in relation to its enhancement of the mutagenicity of benzo[alpha]pyrene.

The effect of norharman on the metabolism of benzo[alpha]pyrene by rat-liver microsomes was studied. Separation of the metabolites into hydrophilic and hydrophobic fractions showed that norharman inhibited the conversion of hydrophobic metabolites to hydrophilic ones. Analysis of the hydrophobic metabolites by high-pressure liquid chromatography showed that norharman also inhibited the disappearance of benzo[alpha]pyrene itself. However, large amounts of hydrophobic metabolites, such as phenol, quinones and diols, were formed in the presence of norharman, and formation of the strong mutagen 7,8-dihydroxybenzo[alpha]pyrene was increased 10-fold by norharman. The increase in formation of this compound may be one of the chief reasons why norharman enhances the mutagenicity of benzo[alpha]pyrene on Salmonella typhimurium.

Alkaloids↗
PubMed1978

Breaking action of reductones related to ascorbic acid on nucleic acids.

The action of two types of ascorbate-related reductones on nucleic acids was investigated by comparison with that of ascorbic acid (AsA). Amino reductone (ScA) and thiol reductone (MHC) caused strandscissions in nucleic acids. This was confirmed by the fact that reductones lowered the viscosity of DNA solution and shifted the peaks of DNA and RNA to the low molecular side in centrifugal profile. Cu2+ strengthened their action as in the case of enediol reductones. The braking activity of thiol reductone is relatively wesk compared with those of amino and enediol reductones. The preferential degradation of spurinic acid was caused with amino and thiol reductones, suggesting that pyrimidine clusters in nucleic acids were susceptible to breakage.

4-Hydroxycoumarins↗
PubMed1977

Comparative studies of lactate dehydrogenases in lactic acid bacteria. Amino-acid composition of an active-site region and chemical properties of the L-lactate dehydrogenase of Lactobacillus casei, Lactobacillus curvatus, Lactobacillus plantarum, and Lactobacillus acidophilus.

The molecular weight, the amino acid composition and the N-terminal and C-terminal amino acids of two allosteric (Lactobacillus casei, L. curvatus) and two non-allosteric (L. plantarum, L. acidophilus) L-lactate dehydrogenases, purified to homogeneity by affinity chromatography, were determined. The amino acid composition of the only tryptic peptide unequivocally common to the fingerprints of the 4 enzymes is virtually identical with that of the arginine peptide, called Arg6 of the the substratebinding site of the L-lactate dehydrogenase dehydrogenase of several animals. However, the 'essential' cysteine residue 165 is replaced by threonine, as it is in the L-lactate dehydrogenase of lobster. In addition, the 4 bacterial peptides differ by one or two changes in single amino acid residues from each other as well as from those of animals. The data indicate that not only the animal L-lactate dehydrogenases, but also the allosteric and lactate dehydrogenases from bacterial sources may have evolved from a common gene.

Amino Acids↗
PubMed1975

In vivo and in vitro phosphorylation of DNA-dependent RNA polymerase of Escherichia coli by bacteriophage-T7-induced protein kinase.

After infection with bacteriophage T7 the beta' and to a lesser extent the beta subunits of E. coli DNA-dependent RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) are phosphorylated by a phage-gene-encoded protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37). The phosphorylation occurs on threonine residues and appears site-specific. It is probably the molecular basis of the early transcriptional control.

Coliphages↗