Abstract
Using the Ouchterlony gel diffusion technique, precipitation zones appearing in agar plates having circular reservoirs filled with ultraviolet-irradiated barley stripe mosaic virus (BSMV) and its homologous antiserum were examined.
With the virus exposed to ultraviolet radiation for 1 hour, no change was recognized in the antigenicity either in flocculation test or in gel diffusion test. Two hours of exposure caused a little decrease, and 3 hours of exposure caused more decrease in the antigenicity. After 6 hours of irradiation, a slight reaction was observed in flocculation test, but no visible precipitation zone could be detected in the gel diffusion test.
The antigenicity was lost after 7 hours of irradiation. The position of the precipitation zones appeared nearer to the midpoint between the antigen and antiserum reservoirs when BSMV was exposed to radiation for 2 to 5 hours. When the dose of irradiation was increased up to 5 hours, the position of the precipitation zones shifted further away from the antigen reservoir, and the curvature of the precipitation zones became smaller than in the case of untreated virus suspensions.
It was after 2 hours of irradiation that the clearest zones were usually observed, although 3 hours of treatment also resulted in clear zones. Virus preparations irradiated for 6 hours showed no visible zone, despite positive reaction in flocculation test.
It was supposed that the formation of precipitation zones were strongly enhanced by the ultraviolet irradiation of the virus, because the virus particles were cut into fragments by irradiation so that their diffusion in the agar gel became faster than in the untreated virus.
