Properties of "diplophage": a lipid-containing bacteriophage

Abstract

The purification and properties of Dp-1, a bacteriophage isolated from Diplococcus [Streptococcus] pneumoniae were described. The phage was sensitive to the organic solvents deoxycholate and Sarkosyl, and its infectivity was reduced by treatment with phospholipase C. EM indicated the presence of a double-layered coat around the phage particles. Purified phage preparations contained lipid amounting to about 8.5% of the dry weight of the phage, and TLC resolved the lipids into 4 components. The phage had a buoyant density in CsCl of 1.47 g/cm3, and a sedimentation constant in 0.1 M NaCl of 313S. Analysis in acrylamide gel electrophoresis indicated the presence of 3 major proteins. Dp-1 DNA shows a density of 1.681 g/cm3. Neutralizing antisera against the phage have a low potency (K < 120/min).