[The modern system for selection of cryptic plasmids based on replicon pMBI].

Cytotoxicity of hybrid plasmide pGalI was associated with the genome site measuring for 1.1.mD and flanked by the recognizing sites of Eco RI restrictase. The cytotoxic effect of pGalI might be limited not only by plasmide pMB9 but also by other plasmides constructed on the base of pMBI replicone. Limitation of the cytotoxicity occurred due to a decrease in amount of the pGalI copies. Capacity of the plasmides studied to limit the pGalI cytotoxicity enabled to clone them as cryptic plasmides under conditions of both simultaneous with pGalI transformation of E. coli and the subsequent selection of clones with the Gal+ phenotype.