Abstract
Summary
1. Cysteine, glutathione, cyanide, and thiocyanate greatly increase the viscosity of alkaline solutions of nucleoprotein (thymus chromosomes), while urea, uracil, thiourea, thiouracil, cystine, and BAL do not do so. Ascorbic acid increases the viscosity only after prolonged incubation. Hydrogen peroxide is without effect on the viscosity. 2. If cysteine is added to the alkaline nucleoprotein solution before X-radiation, the expected reduction in viscosity is largely prevented. If the cysteine is added after X-radiation, it is much less effective in this respect. 3. The suggestion is made that these phenomena may be relevant to the question of the mechanism of cysteine and some other agents in increasing resistance of organisms to X-ray lethality.
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