EVIDENCE OF LYSOGENY IN DERIVATIVES OF ESCHERICHIA COLI.

Frampton, E. W. (The University of Texas M. D. Anderson Hospital and Tumor Institute, Houston), and B. R. Brinkley. Evidence of lysogeny in derivatives of Escherichia coli. J. Bacteriol. 90:446-452. 1965.-Exposure of cultures of several thymine-requiring derivatives of Escherichia coli strain 15 to radiation [X rays or ultraviolet (UV)] resulted in an increased synthesis of ribonucleic acid (RNA) as measured by the incorporation of radioactive uridine. In addition to radiation, mitomycin C (5 or 25 mug/ml) or growth in the absence of thymine also stimulated RNA synthesis in cultures in which the bulk of RNA synthesis was terminated by a shift-down in growth conditions. RNA purified from X-irradiated bacteria was resolved on columns of methylated serum albumin and yielded an elution profile which appeared similar to RNA synthesized by phage-infected bacteria. Electron microscopic examination of cultures induced to lyse by exposure to UV radiation, or by growth in the presence of 5-bromouracil before exposure to radiation (X rays or UV), showed the presence of mostly incomplete phage particles.