Regulation of Penicillinase Synthesis: a Mutation in Staphylococcus aureus Unlinked to the Penicillinase Plasmid That Reduces Penicillinase Inducibility

摘要

A mutant of Staphylococcus aureus strain 655 was isolated that is restricted in penicillinase induction. Wild-type plasmids that bear penicillinase determinants could not be fully induced in this mutant, 655par-1; hence, the responsible mutation is not located on the plasmid. Mutant plasmid PI₂₅₈penI443, which produces penicillinase constitutively in wild-type cells, was fully constitutive for penicillinase production when it was harbored by mutant 655par-1. Therefore, the bacterial mutation does not interfere directly with the transcription of the penZ gene or translation of the penicillinase messenger ribonucleic acid. Mutant plasmid PII₁₄₇penI220 was fully inducible in the mutant bacterium, even though the wild-type plasmid PII₁₄₇ was only partially inducible in the par-1 mutant. Thus, in the presence of inducer, complementation appears to occur between the product of the par-1 gene and the product of the penI220 gene. These results suggest that the par-1 gene codes for a penicillinase antire-pressor.