[Heterogeneity of a Pseudomonas bacteriophage population]

Twenty-five isolates of virulent bacteriophages for Pseudomonas belonging to the morphological group C (Bradley, 1967) were obtained from different natural habitats. The phages of each isolate were found to differ from one another in at least one of the following characteristics: the sensitivity to an osmotic shock, to heating at 60 degrees C and to UV; the ability to cause lysis of 86 Pseudomonas strains; the reaction of neutralisation with antisera. At the same time, the phages were related by the existence of common antigens. These properties are responsible for the genetic stability of the bacteriophages in their complicated relationship with their host, Pseudomonas bacteria.