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Biomedical subjects

S Miyake

Publications and source records attributed to S Miyake.

At least 397 records · Page 22Linked to original sources
PubMed1975

[Morphological differentiation in vitro of human continuous and functional neuroblastoma cell line, NB-I under treatment of (But)2cAMP (author's transl)].

Human neuroblastoma cell line (NB-I), obtained from metastatic neck lymph node of 2.3 y-o, boy, is established and maintained in vitro for more than 3 years in our department. The cells have been proliferated in 10% calf serum in EAGLE's medium, in closed stational culture system. The cell line has characteristic activities of rather rapid growth (Tg = 40 or 50h, 1974) catecholamine metabolism and chromosomal abnormality, bearing two marker chromosomes. NB-I cells are uncloned because of co-adhesiveness but biochemically identified as adrenergic line. Morphologically, they are round or tear-drop like in shape with delicate short protoplasmic processes. NB-I cells exhibit remarkable morphological differentiation and maturation under treatment of (But)2cAMP (final concentration, 1mM/ml). A longer time (1-2 weeks) for differentiation, however, is needed in comparison with that of mouse neuroblastoma cell lines. The NB-I cells exhibit hypertrophy of cytoplasma and nuclei in size, elongation of cytoplasmic processes, as well as the tendency of flattness and multipolarity of cells. Electronmicroscopically, the cells that showed scant organella but plentiful polysomes in the specimen, obtained during autopsy, reveal an increase of cell organellae after implantation in vitro: Golgi apparatus, neurotubules and neural dense bodies appeared in cytoplasma. These organellae characteristic of sympathetic neuron are much more increased under treatment of (But)2cAMP in 3 weeks. Core-vesicle like dense bodies are extremely rich in periphery of perikaryon and elongated processes (100 - 150 mu in diameter). Microtubules are also increased, running in bundles in processes. The NB-I cells are considered to differentiate and approach to matured neurons in vitro.

Bucladesine↗
PubMed1972

Phenotype of a temperature-sensitive, respiration-deficient (cyt) mutant of yeast.

A temperature-sensitive respiration-deficient mutant of yeast lacks hemoproteins and accumulates coproporphyrin III when cultivated at elevated temperatures. Cells grown at 20 C respired normally and contained cytochromes a, b, and c. Cells grown at 35 C showed respiration-deficient mutant characters; they did not respire, lacked cytochromes, and accumulated coproporphyrin III. Addition of protoporphyrin IX or protohemin IX to the culture medium restored the respiratory activity of this mutant during growth at 35 C. The activities of various enzymes, including succinate-2,6-dichlorophenol indophenol (DCPIP), reduced nicotinamide adenine dinucleotide (NADH(2))-DCPIP, succinate-cytochrome c, and NADH(2)-cytochrome c oxidoreductase, and cytochrome oxidase, and the cytochrome c content of cells cultured in various conditions were determined. Changes in the number and structure of mitochondria were associated with changes in respiratory activity.

Cell-Free System↗
PubMed1968

Coproporphyrinogenase in a respiration-deficient mutant of yeast lacking all cytochromes and accumulating coproporphyrin.

In an earlier report, a respiration-deficient mutant of yeast which lacks all cytochromes and hemoproteins and accumulates coproporphyrin was described. This respiration-deficient mutant was temperature-sensitive and resulted from the single chromosomal gene(cyt). In this study, the activity of coproporphyrinogenase, catalyzing the conversion of coproporphyrinogen to protoporphyrinogen, was assayed in the cyt mutant and wild strains. Coproporphyrinogenase activity was 10 times higher in the cyt mutant than in the wild strains. Cells of the cyt mutant grown at 20 C had less activity than those grown at 35 C. The Michaelis constants, pH optima, and temperature activations of the enzymes of the cyt mutant and the wild strains were similar. The significance of the higher activity of this enzyme in the cyt mutant, in which this enzymatic step is apparently blocked in vivo, is discussed.

Carboxy-Lyases↗