The Ultraviolet Sensitivity of Frozen Phage

Abstract
Phage P22 of Salmonella typhimurium is much more sensitive to 2537-A UV light when irradiated in frozen (-80[degree]C) aqueous suspension than when irradiated at room temperature in the liquid phase. The absence of a striking hypersensitivity of frozen phage to 2894-A light suggests that the effect is on phage DNA rather than on phage protein. Hypersensitivity to germicidal light is not found with phage irradiated in frozen glycerol. It is suggested that the crystalline state of water is a requisite for the effect of germicidal light on frozen phage.