[The genetic regulation of the conjugative properties of plasmid complex pAP18 in E. coli cells]

Natural plasmid complex pAP18 discovered in E. coli cells consists of F-like plasmid pAP18-1 (Tc, ColV) and N-like plasmid pAP18-2 (Sm) which differ in their genetic transfer. Plasmid pAP18-1 is able to inhibit transfer of plasmid pAP18-2 but not vice versa. These systems are active both in cells of serologically typed and untypable E. coli strains.