Breakdown of Ribosomal RNA Caused by Ionizing or Ultra-violet Irradiation of Several Bacterial Strains

Summary

Post-irradiation breakdown of RNA was studied in five strains of Escherichia coli. The breakdown was not dependent on the dose-rate; oxygen enhanced the effect by a factor of 3·4. In all strains of E. coli, regardless of the dose of x-radiation, the breakdown proceeded after a lag of 30 min; the rate of the breakdown was dose-dependent and the same for all the strains examined at doses up to 19 krads. Radio-resistant strains were able to degrade more RNA than radiosensitive ones if higher doses were applied. Micrococcus lysodeikticus revealed a post-irradiation breakdown of RNA similar to that in E. coli, whereas M. radiodurans showed a marked stability of its RNA in spite of doses ten times higher being used. Ultra-violet light was able to cause a similar breakdown of RNA in E. coli.