The Effects of Some Chemicals on the Infectivity of Cucumber Isolate of Hop Stunt Viroid (Cucumber Pale Fruit Viroid)

Abstract

The effects of the addition of bentonite, tannic acid, sodium oxalate, yeast-RNA, RNase, acridine orange, methylene blue, and toluidine blue on the infectivity of cucumber isolate of hop stunt viroid (HSV-C) were assayed by means of the infectivity index. The infectivity of HSV-C was increased by bentonite, but was not by sodium oxalate and yeast-RNA. The infectivity of HSV-C was increased slightly by tannic acid at a concentration of 0.1mg/ml, and decreased by tannic acid or yeast-RNA at a concentration of 1.0mg/ml. HSV-C was completely inactivated by pancreatic RNase, and the inactivation was appreciably counteracted by the addition of bentonite to the mixture of HSV-C and RNase. HSV-C was inactivated by the addition of acridine orange, methylene blue, or toluidine blue O to HSV-C under the irradiation of visible light, while the infectivity of HSV-C was slightly reduced when incubated in a dark room. The inactivating effect of methylene blue was higher than that of the other dyes. The inactivation of HSV-C by dyes was obviously counteracted with the addition of bentonite to the mixture of HSV-C and dye.