Exaltation of the development of poliovirus by semicarbazide

Grossberg, Sidney E. (Institut Pasteur, Paris, France), Marguerite Lwoff, and André Lwoff. Exaltation of the development of poliovirus by semicarbazide. J. Bacteriol. 92:1473-1477. 1966.-Semicarbazide (NH(2)-NH-CO-NH(2)) remarkably increases the development of poliovirus. In single-cycle experiments, semicarbazide (SCZ) acted to (i) diminish the length of the latent period, (ii) increase the rate of production of virions, and (iii) increase the final yield of virus. These effects were demonstrable in KB cells, a human malignant cell line, and other primate cells. The dose range over which the compound exerts its effect was relatively large, i.e., from 0.3 to 20 mm, whereas higher concentrations inhibited viral growth. SCZ achieved its exalting effect only when it was added during the first 3 hr of viral development; later addition had no effect. Withdrawal of SCZ at intervals during the viral cycle confirmed that its action occurred within 3 hr after infection. The possible mode of action of SCZ is discussed. SCZ appeared to act, at least in part, by increasing the rate of synthesis of the viral ribonucleic acid.