A turbid plaque-forming mutant of phage P1 that cannot lysogenize Escherichia coli

Abstract

The isolation and characterization of a new P1 mutant, called P1 lyg, is described. P1 lyg phage form turbid plaques, but are defective in ability to lysogenize Escherichia coli. The lyg − allele cannot be rescued from a P1 cryptic lysogen, and data from three point crosses show that lyg maps near vir and c4. A lyg mutant does not prevent a lyg + phage in the same cell from lysogenizing, but a lyg mutant cannot exist alone as a stable prophage even after mixed infection with lyg +.