Interaction of bacteriophage O2 with strains of the genus Oerskovia.

Bacteriophage O2 multiplies normally on Oerskovia turbata IMET 47 153. It has a burst size of about 100 p.f.u. per infected cell and a latent period of 100 min at 30 degrees C. On Oerskovia xanthineolytica IMET 47 383 clear spots were formed after addition of high phage concentrations onto agar top layers. By phase contrast observation, and measurement of the optical density of infected cultures, it was found that the clearing effect on strain IMET 47 383 was due to lysis-from-without. Phage O2 adsorbs and injects its DNA into cells of strain IMET 47 383 but phage multiplication does not occur, and the phage DNA becomes degraded. Inhibition of phage DNA injection by the combined action of xanthotoxin -- u.v. irradiation abolished the clearing activity of phage lysates. Therefore, both adsorption and DNA injection seem to be prerequisites for the release of a lytic activity out of the phage particle, which is responsible for the clearing effect on strain IMET 47 383.