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A Kuninaka

Publications and source records attributed to A Kuninaka.

25 records · Page 2Linked to original sources
PubMed1979

Effect of nucleosides on interferon production and development of antiviral state induced by poly I.poly C.

Effect of nucleosides both on induction of antiviral state in chick embryo cells (CEC) or rabbit kidney cells (RK13) and on interferon production in RK13 or mouse fibroblast cells (L cells) by polyriboinosinic-polyribocytidylic acid (poly I.poly C) was studied. Addition of inosine or a fifty-fifty mixture of inosine and uridine at a final concentration of 0.1 mM to 10 mM to a growth medium enhanced development of antiviral state in CEC. The nucleoside effect was also observed in RK13 at 0.1 mM but not at a concentration higher than 1 mM. Interferon production in RK13 by superinduction (sequential treatment with metabolic inhibitors after exposure to poly I.poly C) was enhanced 1.5- to 4.0-fold by addition of the nucleoside mixture to the growth medium. When RK13 was pretreated with 10 units per ml of interferon and then superinduced by inhibitors, the enhancing effect of nucleosides on interferon production was not observed. Interferon production in L cells was potentiated a little by addition of 1 mM of the nucleoside mixture to the growth medium. The effect of nucleoside was not observed when the nucleosides were added after exposure to poly I.poly C. The nucleoside effect may be applicable for production of high titered interferon.

Animals↗
PubMed1979

In vitro antiherpesviral activity of 5-alkyl derivatives of 1-beta-D-arabinofuranosyluracil.

Several 5-alkyl derivatives of 1-beta-d-arabinofuranosyluracil (araU) were tested for antiherpesviral activity and inhibitory action on cell growth in human embryonic lung fibroblasts. 1-beta-d-Arabinofuranosylcytosine, 9-beta-d-arabinofuranosyladenine, and 5-iododeoxyuridine (IUdR) were included as reference materials. Among the 5-alkyl derivatives of araU, arabinosylthymine was the most active, followed by 5-ethyl- and 5-propyl-araU. 5-Ethyl-araU was as active as IUdR and more active than 9-beta-d-arabinofuranosyladenine against herpes simplex virus (HSV) type 1 and did not inhibit cell growth at a concentration as high as 1,000 mug/ml. 5-Butyl- and 5-methoxymethyl-araU, as well as araU, exhibited relatively low activity. The araU derivatives tested were as active against HSV WT-34, an isolate from a patient with keratitis, as against HSV type 1. Against an IUdR-resistant isolate, HSV WT-20, arabinosylthymine was less inhibitory than IUdR. Deoxyribonucleic acid synthesis in HSV type 1-infected cells was markedly inhibited by arabinosylthymine, IUdR, and 5-ethyl-araU, whereas cellular deoxyribonucleic acid synthesis in uninfected cells was significantly inhibited by IUdR but not by arabinosylthymine or 5-ethyl-araU.

Arabinofuranosyluracil↗
PubMed1976

Relationship between the molecular size of poly I-poly C and its biological activity.

Seven polyinosinic-polycytidylic acid (poly I-poly C) preparations, ranging from 4.2 S to 21.2 S, prepared from various sizes of polyinosinate and polycytidylate, were examined for toxicity and interferon-inducing activity in mice. The increase in size of poly I-poly C was accompanied by increases both in the maximal amount of interferon produced and in the length of persistence of a high level of interferon in plasma. Toxicity of poly I-poly C was proportional to the molecular size within the range of 8 S to 16 S. The amount of interferon induced by 1/5 LD50 of poly I-poly C depended on the size of the inducer, being increasingly lower with progressively smaller sizes. Next, activities of poly I-poly C in culture cells were examined. The resistance-inducing activity of poly I-poly C in primary chick embryo cells (CEC) increased with the size of the inducer (4.2 S to 11.6 S), whereas the activity in L cells was not so markedly dependent upon its molecular size as in CEC. In the presence of calf serum during induction of resistance the activity was lowered. The activities of preparations with small molecular sizes were affected by calf serum more markedly than those of large molecular sizes. The interferon-inducing activity in RK13 was not appreciably influenced by the size of poly I-poly C, especially in the presence of DEAE-dextran, while the activity in L cells was markedly dependent upon the size of the inducer. These results suggest that the influence of the molecular size of poly I-poly C upon the resistance-inducing and interferon-inducing activities varies among different kinds of cells, and alters in the presence of serum or DEAE-dextran.

Animals↗
PubMed1969

The relationship of DNA replication to the control of protein synthesis in protoplasts of T4-infected Escherichia coli B.

The relationship of DNA replication to the control of early enzyme synthesis and the formation of late proteins was studied in protoplasts of E. coli B cells infected with an amber mutant, T4am130. In this phage-host system the bacterial DNA is not completely degraded, and the onset and the extent of phage DNA synthesis could be regulated by use of 5-fluorodeoxyuridine and thymidine. It was found that DNA replication is necessary for the transcription of "late" regions of the phage genome and, thus, for the synthesis of late proteins. In addition, the sustained synthesis of late RNA and the tail-fiber protein was shown to require the continued replication of DNA. Furthermore, the mechanism regulating the cessation of early enzyme synthesis appeared to become operative shortly after the onset of DNA replication and required a limited amount of DNA synthesis for its full expression.

Carbon Isotopes↗