Ultraviolet Inactivation of the Ability of E. Coli to Support the Growth of Phage T7: An Action Spectrum

Abstract—The action spectrum for inactivation of the capacity of stationary‐phase Escherichia coli B to support the growth of T7 bacteriophage was measured, using radiation 240–405 nm in wavelength. The action spectrum has a minimum at 254 nm, a maximum at 267 nm, and a shoulder between 313 and 334 nm, followed by a decrease at longer wavelengths, indicating that nucleic acid is probably not the target for capacity inactivation. Deoxycytidine, cytidine, thiamine, and some proteins have absorption spectra similar to the far‐ultraviolet (240–300 nm) portion of this action spectrum.