The Mechanisms and Effects of Plant Activation of Chemicals in Environment.
Final rept. 30 Sep 91-29 Jan 95,
ILLINOIS UNIV AT URBANA
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Plant activation is the process by which a promutagen is metabolically transformed into a mutagen by a plant system. Plants can activate promutagens into stable mutagens and these genotoxic agents may be hazardous to the environment and to the public health. This research established that a series of environmental arylamines that included rn-phenylenediamine, 2,4-diaminotoluene, benzidine, 4-aminobiphenyl, 2-aminofluorene and 2-naphthylamine could be activated by cultured plant cells into agents that were directly mutagenic in Salmonella typhimurium tester strains. The mechanism of the plant-activation of these arylamines was dependent upon plant peroxidases and did not involve cytodirome PA5O mediated monooxygenation. The plant-activated products were assocneed with a high moleclar weight fraction 100 kDa isolated by ultrafiltration membrane size exclusion. These products were stable some having no reduction in their mutagenic potency after 1 yr. The plant-activated arylarnine products were subsates for Sahnonelta and human NAT2 Offl-aoetyltransferases. These products also induoed unique mutant spectra at both the hisD3O52 and hisG46 target alleles in S. typhimunum. Preliminary results indicate that we have isolated the plant-activated mPDA DNA adducts from treated S. typhimurium cells. Finally, plant- or mammalian-activated arylamines demonstrated a synergic genotoxic response in the presence of the non-mutagenic organophosphorus ester insecticide product, paraoxon. These data suggest that plant-activated arykmines and OP-oxon products may amplify the genotoxic burden of arylamines in the environment.