Increased cotransformation of distant markers and altered patterns of DNA-cell interactions following the exposure of transforming DNA to two carcinogenic and mutagenic alkylating agents, diethyl and dimethyl sulfate

Abstract

Transforming DNA exposed to either diethyl sulfate (diES) or dimethyl sulfate (diMS) is inactivated. The rate of inactivation depends on the marker tested and on the chemical used: diMS is more active than diES. Cotransformation of linked markers is similarly depressed. In contrast, there is a transient increase in the cotransformation of distant, unlinked markers. These observations indicate that some of the intermolecular complexes of transforming DNA created in the test tube by the treatment with diES and diMS are biologically active. Radioactively labeled DNA treated with diES or diMS changes its patterns of interaction with cellular surfaces that are characteristic of untreated DNA. A possibility is considered that such alterations in DNA-protein interactions as well as the ability of these alkylating agents to transpose fragments of chromosomal material may play an important role in the processes of mutagenesis and, especially, carcinogenesis.

Practical and theoretical aspects of the DCB assay for carcinogenic and other genotoxic agents

“…The techniques used were published earlier 1982). Bacillus subtilis auxotroph strain SB238, which requires tryptophan, tyrosine, and leucine for 392/KUBINSKI AND KUBINSKI growth, was exposed to DNA obtained from a prototrophic strain 764.…”

“…DNA was extracted from donor prototrophic bacteria as described elsewhere (Kubinski, et al, 1966;Kubinski and Kubinski, 1982) and used for transformation either untreated or after being treated with one of the carcinogenic chemicals. In most experiments summarized in the RESULTS section, the chemical was subsequently removed by either dialysis, alcohol precipitation, filtration through gels (Sephadex G25) or sucrose density gradient centrifugation.…”