Induction of the synthesis of phage and colicin in a culture medium irradiated by UV‐rays

Abstract

It is possible to increase considerably the spontaneous production of the bacteriophage in many lysogenic cultures by induction; this induction has so far been successfully obtained by many physical and chemical factors. Of the physical agents the most used is UV-radiation a t a wave-length of about 2537 A, absorbedselectively by DNA, andionising radiation: X-rays a t a wave-length of 0.9 A and gamma-rays a t an average energy of photons 600 keV and further, alpha particlesand deuterons. Similar effect wasalso obtained bythermo-shocks (CAVALLO 1953).Of the chemical substances used as inducing agents the best known are hydrogen peroxide and some other organic peroxides (terbutylperoxide and butadiendioxide), furthermore epoxides, ethyleneimines, 1-azaserine, mustard gas, and especially nitrogen mustard: So far unique is the account of induction by ribonuclease (E'IETRZYKOWSKA 1960). Sulfhydril compounds (reduced glutathione, thiomalic acid, thioglycolic acid) bring about induction