CHARACTERIZATION OF 2 SALMONELLA-NEWPORT BACTERIOPHAGES

S. newport phages 16-19 and 7-11 have very long heads and are members of 2 rare and so far little-known phage groups. Both produce various morphological aberrations. Preparations of phage 7-11 contain numerous polyheads and about 0.4% short heads belonging to 9 size classes. In addition, 1 giant phage particle was observed. The head of phage 7-11 seems to be an icosahedron which became elongated by adding successive rows of subunits. Phages 16-19 and 7-11 have buoyant densities in CsCl of 1.43 and 1.48 g/ml and particle weights of 103 and 204 .times. 106, respectively. Both viruses contain double-stranded DNA, internal proteins and sugars. Phage 16-19 contains 46.5% DNA of 35 .times. 106 MW, and glucose. Phage 7-11 contains 47.5% DNA of 108 .times. 106 MW and mannose. Base compositions of phage and S. newport DNA were determined from buoyant densities, melting point and acid hydrolysis. Phage 16-19 contains 5.4% 5-methylcytosine.