T2 Phage Sensitization by Linear and Angular Furocoumarins

Abstract

Abstract T2 bacteriophage sensitization has been studied using two furocoumarins capable of linking co­valently to DNA to the same extent but producing different damages, psoralen and 4,5′-dimethylangelicin. Psoralen is a well-known linear furocoumarin capable of inducing in DNA both mono-adducts and cross-links; 4,5′-dimethylangelicin is a new angular compound known as a pure mo­nofunctional reagent. In the sensitization of T2 mature virions both drugs proved very active, yielding survival curves practically superimposable; on the contrary, in the experiments with the T2 veg­etative form, i. e. its DNA inside the host, 4,5′-dimethylangelicin resulted much less effective, resembling the picture observed in the inactivation of the host bacteria. This result did not appear related to an enhancement of DNA repair by a Weigle effect. The different killing activity of 4,5′-dimethylangelicin can be explained supposing that this drug is capable of inducing cross-links in T2 DNA inside the virus core, in which it exists in a very folded form, but not in the same DNA after injection into the host bacteria.