Inactivation of bacteriophages T7 and phiX174 by radiomimetics.

Inactivation of phages T7 and phiX174 induced by the radiomimetics N-nitroso-N-methylurea (NMU) and N-acetylethylenimine (AEI) has been studied. In semilogarithmic scale the kinetic curves of phage inactivation were steplike in character. This was connected with the occurrence of several processes in the system. A possible kinetic model has been proposed for the process of NMU-induced phage inactivation. The model is applicable to initial phage inactivation only. From the model a kinetic curve parameter, rho can be determined which characterizes the radiomimetic effect on different phages and determines the changes in the repair system after caffeine treatment. NMU exerted a post-inactivation effect on the phage T7. Also the NMU-induced phage T7 post-inactivation kinetic curves were of steplike character. They can be described as a sum of two exponential processes of different rate constant. The rate constant for the first stage of the post-inactivation process was close to the depurinization rate constant found in the literature.