Abstract
An R' plasmid, R'PA1, carrying a 3- to 4-min segment of the Pseudomonas aeruginosa chromosome has been derived from the incP-1 plasmid R68.45. The chromosomal segment includes the markers argA, argB, argH, and lys-12. The plasmid retains all the properties of R68.45, including chromosome mobilization ability and wide bacterial host range. R'PA1 reverts to R68.45 in rec+ strains of P. aeruginosa, but it can be maintained in a recA strain.