Biochemical studies on the lethal effects of solar and artificial ultraviolet radiation on Staphylococcus aureus.

The effects of UV-B radiation generated in the laboratory and as a component of sunlight on the viability and particular biochemical activities of the bacterium Staphylococcus aureus have been examined. UV-B radiation progressively inhibits protein synthesis (assayed as 3H-alanine incorporation) and kills cells. Cell respiration, and RNA and DNA synthesis (3H-uridine and 3H-thymidine incorporation) were not greatly affected by UV-B irradiation. The OH. and 1O2-free radical scavengers protected cells against killing and inhibition of protein synthesis by UV-B, suggesting that such radicals mediate the effects of UV-B on this organism. A similar protective effect using a ferric ion chelator suggests an important role for metallic ions in UV-B lethality.