Properties of Thermoactinomyces vulgaris phage Ta1 and its extracted DNA.

The virulent phage Ta1 was obtained in good yields from infected cultures of Thermoactinomyces vulgaris 1227. The purified phage was found to sediment with a single band, the sedimentation constant being (519 +/- 14)S, and to exhibit a typical nucleoprotein behaviour in UV-spectrophotometric and CD experiments. The Ta1 phage consists of a hexagonal head about 0.056 micrometers in diameter and a very short tail. It is morphologically similar to the temperate Salmonella phage P22. The nucleic acid extracted from the phage was found to be a double-stranded linear DNA with a G+C content of 42 mole-% as deduced both from its melting temperature and buoyant density in CsCl. Analytical sedimentation revealed a high degree of molecular homogeneity of Ta1 Dna. the sedimentation constant of this DNA amounts to (35.9 +/- 0.3)S, corresponding to a DNA molecular weight of about 29 millions daltons. The biological activity of Ta1 DNA was indicated by its ability to infect the mycelium of the components T. vulgaris strain 1227 and to give rise to mature phages.