Restriction-deficient Mutants of Staphylococcus aureus

Abstract

A series of restriction-deficient mutants was isolated from non-lysogenic strains of S. aureus belonging to phage groups I and II. Some mutants were sensitive to all phages tested. With 1 possible exception all mutants were unaffected in their modification systems. The breakdown of phage DNA, restricted in the parental strains, was reduced in both mutants tested. The restriction in propagating strain 3A could be transduced to its restriction-deficient mutant. The transduction efficiency increased after UV irradiation of the transducing phage, suggesting that the gene for restriction is present on the bacterial chromosome.