Altered phage P1 attachment to strains of Escherichia coli carrying the plasmid ColV,I-K94.

Phages P1vir and P1cmclrf100 failed to form plaques on or multiply in Escherichia coli strains carrying the ColV,I-K94 plasmid; with P1cmclr100, the effect occurred both with phage from the lytic cycle and with that induced from a lysogen. The effect was on attachment, these P1 phages attaching poorly to ColV,I-K94+ strains. This receptor defect appeared to result mainly from the presence of ColV-encoded transfer and colicin components in the cells carrying ColV,I-K94 and it was specific to this plasmid. Phage Mu (which uses an attachment mechanism similar to that of phage P1) in the G(+) form attached to both Col- and ColV,I-K94+ strains but the G(-) form attached to neither type.