Post-Irradiation sensitization to γ-rays in the blue-green alga, Anacystis nidulans by a rifamycin derivative (DMB) which is active on RNA-directed DNA polymerase

Summary The radiosensitizing effect of a rifamycin derivate — dimethylbenzyldesmethylrifampicin (DMB) was compared with that of actinomycin D in unicellular blue-green alga, Anacystis nidulans . These agents are active when added after irradiation and potentiate γ-ray-induced killing in cells. Pre-irradiation treatment of cells with DMB or actinomycin D is ineffective. DMB, which is strong inhibitor of RNA-directed DNA polymerase, greatly decreased the survival of irradiated A. nidulans cells compared to actinomycin D. This phenomenon of post-irradiation sensitization by DMB is probably a result of inhibition of reverse transcription process in the blue-green algae.