Isolation and Characterization of Bacteriophages Active against Stalked Bacteria

Abstract

The isolation and properties of 23 phages lytic for stalked bacteria of the genera Caulobacter and Asticcacaulis are described. They fall into seven groups on the basis of host range and serological properties. Phages of groups I-VI attack only Caulobacter species; those of group VII, only Asticcacaulis. Groups I-III comprise DNA viruses with long flexible tails and of unusually large size, the heads having dimensions of 50 x 170 m[mu]. Groups IV-VI comprise RNA viruses of simple structure, 21-23 m[mu] in diameter. The specific Asticcacaulis phages (group VII) are tailed DNA viruses, similar in form and size to coliphage lambda. The implications of this study for the taxonomy of the caulobacters are discussed.