The Replication of Bacteriophage K DNA in Staphylococcus aureus

Summary Three intracellular forms of K phage DNA were identified by sucrose gradient centrifugation and electron microscopy: (i) a form with sedimentation characteristics similar to mature phage DNA; (ii) a fast-sedimenting form (FSF) and (iii) a rapidly sedimenting complex (RSC). The FSF sedimented in a position intermediate between mature DNA and the RSC and comprised one genome length of phage DNA in association with a small mass of non-DNA material. Each RSC was associated with a discrete mass of non-DNA material about three times the size of that in the FSF and formed a large tangled structure containing up to 30 or more phage equivalents of DNA. The RSC was identified as the major replicative form.