[Plasmid preservation in Escherichia coli cells in batch and continuous cultivation]

The growth kinetics of plasmid and nonplasmid strains of 2 isogenic E. coli K12 culture lines has been studied in experiments on batch and continuous cultivation. Under the optimum conditions the growth rate of R+- and R- cells is the same; under the conditions of limited glucose supply the plasmid strains grown slower, as their energy is partly spent on maintaining plasmids in the cell.