A bacteriophage of Rhodopseudomonas blastica

Abstract

A bacteriophage, 4BHG1, was isolated from a small eutrophic pond from which its host, Rhodopseudomonas blastica, was originally obtained. It is a lytic bacteriophage specific for R. blastica which also causes non-specific lysis of Rhodobacter sphaeroides 8253. 4BHGl has an icosahedral head of 62 nm diameter and a short 39 nm tail. Caesium chloride density gradient centrifugation of infected cell lysates gave a single bacteriophage band a t a density of 1.385 g ~m -~, but also occasionally a second band was observed at a lower density. No differences were apparent between bacteriophage taken from either of the two bands. 4BHG1 contained double-stranded DNA with a size of 48 kb and a G +C content of 50.6 mol%. The bacteriophage adsorbed to both photosynthetically and chemoheterotrophically grown R. blastica a t an identical rate of 1-39 x studies of the bacteriophage under these physiological regimes showed no differences in the latent and rise periods and only slight changes in the burst size. Adsorption of this bacteriophage is cell-surface specific and attachment only occurs to the 'older' pole of the budding reproductive cell.ml-1 mi+. One-step growth curves and kinetic