FP5 Factor, an Undescribed Sex Factor of Pseudomonas aeruginosa

Abstract

A Pseudomonas aeruginosa, strain Ps5-70 which was mercury-resistant, was found to have a sex factor. This sex factor, designated as FP5 factor, mediated chromosome transfer by conjugation. Crosses between Ps5-70, FP5⁺ and PAO, FP2⁺ strain of Holloway were fertile, and Ps5-70 acted as the donor. Some of the recombinants between FP5⁺ and FP5^- strains displayed maleness, and those recombinants usually acquired mercury resistance. So, transferability of FP5 factor itself and a very close association between the two determinants of FP5, one for fertility and the other for mercury resistance, were proved similar to the FP2 factor. Female sublines of Ps5-70 which behaved as recipients in intrastrain crosses were obtainable from cultures multiplied in the presence of acriflavin. Those females still retained mercury resistance. An R factor originated in P. aeruginosa interfered with the recombinant formation mediated by FP5 factor when the two episomcs coexisted within a single cell.