[Mutations of the genetic region Fin of the F-like plasmid pAP18-1].

With help of nitrosoguanidine 60 mutants of F-like plasmids pAP18-1 drd::Tn 5 and pAP18-1::Tn 9 were induced which determined resistance of E. coli cells of specific phage MS2. Mutational changes in fin-locus of those plasmids were accompanied by phenotypic reversion Fin(-)-Fin+.