Assessment of genotoxicity of disinfection by-products (DBPs) in drinking water generated from different disinfection processesWe calibrated and compared genotoxicity assays using transgenic mammalian cells and traditional bacterial assays to better assess the genotoxic risks associated with drinking water disinfection by-products (DBPs) and DBP mixtures. Our data derived from S. typhimurium provide a link to the literature while mammalian cell data provide an endpoint more relevant to the human condition. The U.S. EPA DBP occurrence data base is being used to direct the selection of agents for genotoxicity testing and to define the impact upon current water disinfection practice.
Isolation of novel antimutagens and anticarcinogens from agricultural products and by-products; analysis of the repression of growth rates of human tumor cell lines by agronomic processing waste fractionsWe are isolating and chemically characterizing antimutagens and human tumor cell growth repressing agents from commercial processing wastes or by-products of corn and soybean. We developed mammalian cell methods to measure the repression of aromatic amine-induced DNA damage by very small amounts of complex mixtures, fractions or individual chemicals isolated from agricultural by-products. We integrate our analytical biological assays with separation and analytical chemistry conducted at the USDA laboratory at Peoria, IL. This research may lead to the isolation of novel chemoprotectants from agronomic commercial processing products and by-products.
Genotoxic synergy between organophosphorus ester insecticides and environmental and dietary aromatic aminesGenotoxic synergy is the interaction of two or more agents that causes an increase in DNA damage greater than the sum of their individual genotoxic effects. We discovered that organophosphorus ester insecticides and several environmental and dietary carcinogenic aromatic amines interact synergistically to generate an enhanced mutagenic response in Salmonella typhimurium and enhanced DNA damage in human lymphocytes. This enhanced genotoxic phenomenon associated with agents that are global environmental contaminants raises concerns about their impact upon the public health, especially for farmers, agricultural workers and residents of rural areas.
Isolation and characterization of plant-activated arylaminesWe published the first conclusive evidence that plants could metabolically convert non-mutagenic chemicals into mutagens that could induce genetic damage in consuming organisms. The plant activation of aromatic amines employs plant peroxidases and results in the generation of high molecular weight products (>100 kDa) that can inflict DNA damage in microbial and mammalian cells. The plant kingdom may be a reservoir for environmental contaminants which may be recycled into the biosphere. If even a small amount of plant-mediated contaminant recycling occurs then the environmental burden of chemical pollutants may be vastly underestimated.