Kohli, R., Gupta, P.K. and Dube, A. Helium-Neon Laser Preirradiation Induces Protection against UVC Radiation in Wild-Type E. coli Strain K12AB1157.
We have observed that preirradiation with a helium-neon laser (632.8 nm) induces protection against UVC radiation in wild-type E. coli strain K12AB1157. The magnitude of protection was found to depend on the helium-neon laser irradiance, exposure time, and period of incubation between helium-neon laser exposure and subsequent UVC irradiation. The optimum values for dose, irradiance and interval between the two exposures were found to be 7 kJ/m2, 100 W/m2 and 1 h, respectively. The possible involvement of singlet oxygen in the helium-neon laser-induced protection is also discussed.