Analysis of DNA adducts from herbicide interactions

AGRO 36

Todd C. Andrade1, Donald W. Boerth, dboerth@umassd.edu1, Erwin Eder2, and Paul Wanek2. (1) Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA 02747, (2) Institute of Toxicology, University of Würzburg, Versbacher Strasse 9, D-8700 Würzburg, NA, Germany
Adduct formations between DNA bases and various xenobiotic molecules have been established as a main source of mutation in biological organisms. The presence of these nucleotide adducts within plants have been previously studied in our laboratory with the use of in vivo experiments along with 32P postlabeling studies. Evidence was found for both direct adducts with the pesticide, as well as indirect adducts formed with products of lipid peroxidation. Many of these xenobiotic compounds, including numerous pesticides, are electrophilic and can react directly at various nucleophilic sites in the nucleic acid bases. The focus of this study was to investigate the susceptibility and reactivity of a set of herbicides towards various nucleotides. Herbicides considered in this study include triclopyr, dichlobenil, 2,4-D, dicamba, and sethoxydim. Another focal point of this research was to isolate possible adduct formations via HPLC methods and to identify the structure of such in vitro adduct products through mass spectroscopy. Information on the molecular structure of these adducts can assist the understanding of the probable reaction mechanisms and recognize various sites of reactivity within the nucleotides. This research confirms the formation of adducts between the DNA bases and several of the herbicides investigated.