Near-UV Irradiation Induces Shock Proteins in Anacystis nidulans R-2; Possible Role of Active Oxygen

Anacystis nidulans R-2 cells were irradiated with near-UV light(295–390 nm) at an intensity that resulted in 30–40%survival. The near-UV light induced the preferential synthesisof sixteen proteins, which were designated UV-shock proteins.Several UV-shock proteins were also induced by heat shock (42?C)and six were synthesized by treatment with methyl viologen.The water-soluble fraction prepared from the cells generatedsuperoxide anion radicals upon irradiation with near-UV light,suggesting the production of active species of oxygen in cellsas a result of exposure to near-UV light. (Received February 18, 1991; Accepted May 24, 1991)