Properties of RP4, an R Factor Which Originated in Pseudomonas aeruginosa S8

Abstract

RP4, an R factor derived from Pseudomonas aeruginosa S8 and specifying resistance to carbenicillin, neomycin, kanamycin, and tetracycline, could be isolated as an extrachromosomal satellite of covalently closed circular DNA (CCC-DNA) of molecular weight about 62 million and of buoyant density 1.719 g/cm 3 (60% guanine plus cytosine). When RP4 was compared by hybridization with RP1, an R factor originating in another strain of P. aeruginosa , it was shown that RP4 contains most, if not all, of the base sequences of RP1, and also additional sequences not found in RP1.