Different restriction profiles of kappa prophage in Serratia marcescens K and HY.

Temperate phage kappa originated from the defectively lysogenic Serratia marcescens strain K, from where it was liberated after uv irradiation with low efficiency. The phage is usually indicated on strain HY that can be easily lysogenized by it and rather efficiently uv-induced. Comparing the Eco RI restriction profiles of the kappa prophage in HY revealed a DNA rearrangement, by which the precursor structure in K is converted into the non-defective form. Apparently the fragment containing the pac sequence is concerned since a phage DNA probe prepared from the assumed initiation fragments of the first particles of the packaging series gave two signals instead of one with genomic K DNA. Since several independent new kappa isolates showed the same Eco RI restriction pattern as the original phage of ELLMAUER and KAPLAN (1959), the generation of kappa is a reproducible event.