Ultraviolet Action Spectrum of T1 Bacteriophage

Abstract

The relative effectiveness of u.-v. light in causing inactivation of Tl bacteriophage was studied. If the number of bacteriophage particles initially present is no, and after receiving an intensity I for a time t, a number n survive, then it was believed the relation n = e-alt would hold where a is a constant for any one no wave length and e is the base of the system of natural logarithms. This relation requires the random absorption of photons and applies only if the bacteriophage layer is uniform, the u.-v. light is uniform and there is no absorption by broth. Results indicated that if allowance was made for departure from these conditions, the realtion was obeyed. The procedure was to measure a for a series of wave lengths of light given by a quartz mercury arc and the resulting plot of a versus wave length is the action spectrum. It was found that the spectral dependence was similar in spite of change of arcs, renewal of the mirror surface, and change of the amt. of dried broth in which the bacteriophage was irradiated.