Isologous Interference with Ultraviolet and X-ray Irradiated Bacteriophage T2.

Levy, Stuart B. (Institut du Radium, Paris, France). Isologous interference with ultraviolet and X-ray irradiated bacteriophage T(2). J. Bacteriol. 87:1330-1338. 1964.-Qualitative and quantitative analysis of the interference capacity of an irradiated T(2) bacteriophage was made with ultraviolet and X-ray irradiation. Two different effects were found to explain the total interference picture in the ultraviolet-irradiated system: exclusion and depression. Exclusion is the absolute inhibition of infectious phage growth in the bacterial host. Depression is the diminution of burst size in instances where the infectious phage has not been excluded. Both effects were seen when the infectious phage was added after the addition of ultraviolet-irradiated phage. Doses between 1,600 and 2,200 ergs/mm(2) (survivals, ca. 10(-7)) showed the greatest exclusion effect (70%). Exclusion was lost between 6,500 and 7,500 ergs/mm(2). The depression effect was highest (90%) at lower doses (survivals, ca. 10(-6)), falling off as the dose range went above 1,600 ergs/mm(2) or survivals of 10(-7). Depression was lost at 3,000 ergs/mm(2). X-ray irradiation (both direct and indirect) to survivals less than 10(-2) showed no interference capacity in the phage irradiated. Indirect X-ray irradiation to survivals between 5 and 10% showed 50% exclusion, but no depression.