The ability of irradiated bacteriophage T2 to initiate the synthesis of deoxycytidylate hydroxymethylase in Escherichia coli

Abstract

Studies have been performed on the ability of bacteriophage T2r + irradiated either with ultraviolet light (UV) or with 1 Mev electrons to initiate the synthesis of deoxycytidylate hydroxymethylase in Escherichia coli. Following infection with irradiated phage, the enzyme activity appears at a decreased rate, but without any significant delay. Hydroxymethylase activity for an unirradiated control stops increasing at 15–20 minutes after infection; instead, synthesis following infection with irradiated phage appears to continue for a longer time. The enzyme-synthesizing ability sensitivities, compared to phage survival, differ markedly with UV and electrons. Nineteen and three phage-lethal hits, respectively, are required to reduce the hydroxymethylase activity to 37% that of the unirradiated control, using UV and electrons. The rate of hydroxymethylase synthesis is the same for infection with three or thirty phage particles per cell.