Nature 227, 606 - 607 (08 August 1970); doi:10.1038/227606a0

Segregation of Transferable R Factors into Escherichia coli Minicells

STUART B. LEVY & PAULA NORMAN^*

Laboratory of Biochemical Pharmacology, National Institue of Arthritis and Metabolic Diseases, National Institutets of Health, Bethesda, Maryland 20014.
^*Present address: Kalamazoo College, Kalamazoo, Michigan 49203.

IT is difficult to isolate the DNA of Escherichia coli episomes because its physical and biological properties are similar to those of the bacterial chromosome. We have solved this problem by isolating the R factor in minicells, tiny DNA-less cells resulting from abnormal cell division of an E. coli mutant¹. Minicells have been used as recipients for DNA transfer from normal cells², but in general, except with F factor alone, the transferred DNA remains as a non-replicating single strand².

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