Use of an Hfr Strain of E. coli for Prescreening of Antitumor antibiotics

Abstract

An Hfr strain if Escherichia coli integratively suppressed by plasmid F showed high susceptibility to agents interacting with DNA at high temperature. Antitumor antibiotics, such as bleomycin, mitomycin C, netropsin, and streptonigrin, which interact with DNA, and intercalating dyes, such as acriflavine, 9-aminoacridine and ethidium bromide, were active in assays of preferential activity against the growth of the Hfr strain at 42°C. In the culture fluid of an actinomycete, dnacins, a new type of antibiotic interacting with DNA, were detected by this assay.