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Biomedical subjects

Y Ogiso

Publications and source records attributed to Y Ogiso.

65 records · Page 4Linked to original sources
PubMed1986

Expression of c-mos proto-oncogene in undifferentiated teratocarcinoma cells.

Proto-oncogene c-mos, the cellular homologue of the transforming gene of Moloney murine sarcoma virus, has been characterized by the lack of expression in a variety of differentiated tissues, possibly because of the existence of an inhibitory upstream sequence. We detected mos-related transcripts in undifferentiated embryonal carcinoma cells of pluripotential cell line 311. The sizes of three major transcripts detected were estimated to be 1.8, 4.6 and 6.1-kilobases (kb) by northern analysis. Furthermore, these transcriptions were suppressed when the cell differentiation was induced by retinoic acid. Taken together, the results suggest that mos product plays a role in early stages of development.

Animals↗
PubMed1983

Mode of cell surface marker changes during retinoic acid-induced differentiation in pluripotent embryonal carcinoma cells.

Pluripotent teratocarcinoma cell line, 311, was cultured in the presence of retinoic acid (RA) and studied for the processes of early marker changes associated with cell differentiation. The cell populations that have lost peanut agglutinin (PNA), Lotus tetragonolobus agglutinin (LTA) or wheat germ agglutinin (WGA) receptor increased in proportion to the period since the start of RA treatment. The kinetics of the appearance of these receptor-negative cell populations suggests that the differentiating cells lose lectin receptors in the order of PNA, LTA and WGA. However, the changes in F9 antigen(s) and LTA receptor occurred at an equal frequency in PNA+ and PNA- cells, indicating that, although the loss of lectin receptors takes place in a distinct order, the change in each receptor itself proceeds independently of the state of other lectin receptors.

Animals↗
PubMed1983

Induction of teratocarcinoma cell differentiation. Effect of the inhibitors of DNA synthesis.

Induction of teratocarcinoma cell (F9) differentiation was studied by using inhibitors of DNA synthesis and several agents known to be differentiation inducers. Inhibition of DNA synthesis induced changes in cell surface marker F9 and stimulated the production of plasminogen activator (PA) in a manner that is dependent upon de novo synthesis of RNA and protein. The results thus indicate close association between inhibition of DNA synthesis and induction of cell differentiation. This approach will be useful in investigating the mechanism of teratocarcinoma cell differentiation.

Animals↗
PubMed1982

Effects of beta-mercaptoethanol-containing medium and feeder cells on the differentiation of embryonal carcinoma cells.

Pluripotent, feeder-dependent teratocarcinoma cell lines were cultured without a feeder layer in a medium containing 10(-4) M beta-mercaptoethanol (beta-medium) and compared for the development of early markers with cells cultured with a feeder layer. The cells cultured in beta-medium lost the PNA (peanut agglutinin) receptor typically at low density. This change was accompanied with enhanced secretion of plasminogen activator and the loss of sensitivity to anti-F9 serum, indicating the stem cell differentiation. In contrast, the cells cultured on a feeder layer did not show any marker changes, thus indicating the lack of differentiation. These results indicate that while the presence of feeder cells inhibits cell differentiation, cultivation in beta-medium permits the differentiation of pluripotent teratocarcinoma cells.

Animals↗
PubMed1977

Effect of zinc ion on the hemolytic activity of thermostable direct hemolysin from Vibrio parahaemolyticus, streptolysin O, and Triton X-100.

The effect of Zn2+ on hemolysis induced by the thermostable direct hemolysin from Vibrio parahaemolyticus (vibriolysin) streptolysin O, and Triton X-100 was studied. We found that in certain buffers, such as tris(hydroxymethyl)-aminomethane-hydrochloride, boric acid-borax, and N-hydroxyethyl piperazine-N'-2-ethanesulfonic acid-sodium hydroxide, hemoglobins released from erythrocytes were easily precipitated by addition of Zn2+, thus resulting in a false inhibition of hemolysin by Zn2+ when hemolysis was assayed by measuring absorbance at 540 nm of released hemoglobins. Under experimental conditions in which hemoglobin was not precipitated, hemolysis induced by streptolysin O was inhibited by Zn2+, whereas that induced by vibriolysin and Triton X-100 was not. Thus, we concluded that the mode of inhibitory action of Zn2+ on hemolysis was not due to a reversible alteration in the state of the lipid bilayer of erythrocytes membranes as proposed by Avigad and Bernheimer (Infect. Immun. 13:1378-1381, 1976).

Buffers↗
PubMed1976

Aminoacyl transfer RNA formation. Binding of cations to transfer RNA and its role in aminoacyl transfer RNA formation.

The role of cations (polyamines and Mg2+) in isoleucyl-tRNA formation catalyzed by purified isolecuyl-tRNA synthetase [EC 6.1.1.5] from Escherichia coli was studied. It was found that spermine, spermidine, and Mg2+ bind to tRNA and that when bound to these cations, tRNA acts as substrate of aminoacylation without requiring further cations. These findings suggest that the primary function of cations in aminoacyl-tRNA formation is to bind to tRNA to stabilize its structure, not to bind to the enzyme to activate it.

Binding Sites↗
PubMed1976

Aminoacyl transfer RNA formation. VII. Lack of correlation between aminoacylation and PPi-ATP exchange catalyzed by isoleucyl-tRNA synthetase of Escherichia coli in the presence of various divalent cations.

Isoleucyl-tRNA formation and isoleucine-dependent PPi-ATP exchange catalyzed by purified isoleucyl-tRNA synthetase [EC 6.1.1.5] of Escherichia coli were studied in the presence of various amounts of either Mg2+, Ca2+, Fe2+, Ni2+, or Cu2+. In the presence of Mg2+, isoleucine-dependent PPi-ATP exchange was observed in parallel with isoleucyl-tRNA formation, while in the presence of Ca2+, isoleucyl-tRNA formation was observed without isoleucine-dependent PPi-ATP exchange. Moreover, isoleucine-dependent PPi-ATP exchange was much more in the presence of Fe2+ than in the presence of Mg2+, while little isoleucyl-tRNA was formed in the presence of Fe2+. In the presence of Ni2+ or Cu2+, neither reaction was observed. These data, indicating that formation of an isoleucyl-AMP-enzyme complex is not a necessary step in isoleucyl-tRNA formation, support the existence of a concerted mechanism of isoleucyl-tRNA formation in E. coli.

Adenosine Triphosphate↗