[The role of plasmids in the cell cycle of Escherichia coli]

The effect of R- and Hly-plasmid differing in phenotype, molecular size, conjugativity, stability and incompatibility properties on the cell cycle and nucleic acids content per cell has been studied in Escherichia coli. According to these properties the plasmids were divided into 3 categories. The possibilities of the autonomous plasmid replicon interactions with the host chromosome are discussed.