MONOCHROMATIC ULTRAVIOLET ACTION SPECTRA AND QUANTUM YIELDS FOR INACTIVATION OF T1 AND T2 ESCHERICHIA COLI BACTERIOPHAGES

Abstract

Action spectra for inactivation of Tl and T2 coliphages were detd. for 9 wavelengths between 2220 and 3022 A. With both phages the action spectrum is of the nucleic acid type with a max. of efficiency at 2650 A, a min. at 2380 A, and with increasing efficiency at the still shorter wavelengths. The quantum yields for inactivation for both phages were nearly constant over the range of wavelengths studied and were found to be about 6 x 10-4 and 3 x 10-4 for T1 and T2 respectively. Thus, whereas Tl requires about 2.5 to 3.0 times as much incident energy as T2 for a given level of inactivation, on the basis of absorbed energy, Tl appears to be the more sensitive to u.-v. Certain difficulties involved in the accurate detn. of quantal efficiencies are pointed out and the significance of quantum yields is briefly discussed.