Bacteriophages of Rhodopseudomonas spheroides : Isolation and Characterization of a Rhodopseudomonas spheroides Bacteriophage

Abstract

A DNA-containing bacteriophage, designated RS1, infecting Rhodopseudomonas spheroides 2.4.1, has been isolated from sewage. The buoyant density of RS1 in CsCl equilibrium centrifugation is 1.50 g/cm 3 , and the buoyant density of RS1 DNA is 1.706. The phage possesses a polyhedral head, approximately 65 nm in diameter, and a tail 60 nm long. When grown on aerobic cells, RS1 has a latent period of 120 min and an average burst size of 20. When grown on anaerobic cells, RS1 has a latent period of 150 min, and a burst size similar to that observed during aerobic infection. The adsorption rate constant of RS1 to aerobic cells is 1.2 × 10 −9 ml/min, and 0.58 × 10 −9 ml/min to anaerobic cells. Adsorption of RS1 to R. spheroides requires the presence of divalent cations.