Effects of post-irradiation incubation on the fibroin synthetic activity of silkgland ribosomes.

Isolated silkgland ribosomes were irradiated with X-rays, and their activities to synthesize fibroin in vitro were examined. A marked decrease in their activities was observed when ribosomes were incubated at 37•Ž following X-irradiation. Per cent decrease in the ribosomal activity leveled off at 37•Ž after 30 minutes incubation . The extent of decrease was dependent on X-ray dose. Treatment of ribosomes with pancreatic ribonuclease showed a decrease in the ribosomal activity. These results suggest that a type of radiation damages on irradiated riboso mes is likely to be revealed during the post-irradiation incubation period through a possible interaction with ribonuclease either activated or released by X-irradiations.