[Content of DNA in cells of Escherichia coli carrying standard R-plasmids]

DNA content was studied in Escherichia coli K12 cells carrying conjugative R plasmids. Cultures at the exponential growth phase were used for the fractionation of nucleic acids. The content of total and chromosomal DNA was found to be much lower in the presence of R plasmids than in the strain carrying no plasmids. The content of RNA also decreased in the cells of E. coli in the presence of R plasmids.