Isolation of the rec mutants in Staphylococcus aureus

A histidine auxotroph ( his −) of Staphylococcus aureus MS3937 and mutants sensitive to ultraviolet (UV) irradiation were obtained. The UV-sensitive mutants were found also to be sensitive to N -methyl- N ′-nitro- N -nitrosoguanidine and mitomycin C, and their sensitivity was accounted for by a defect in deoxyribonucleic acid repair. Transduction of either chromosomal or plasmid markers to UV-sensitive mutants showed that these staphylococcus mutants are of the recA (reckless) type mutants as reported in Escherichia coli and Salmonella typhimurium; therefore the UV-sensitive mutants ( uvr −) were renamed recombination-deficient mutants ( rec −). The biochemical and genetic properties of these mutants are described, and their usefulness for studies of staphylococcal plasmids is discussed.