Mutagenicity synergy between paraoxon and mammalian or plant-activated aromatic amines

Elizabeth D. Wagner, Karen Repetny, Jane S. Tan, Tomáš Gichner, Michael Jacob Plewa

Research output: Contribution to journalArticlepeer-review


Paraoxon (diethyl-p-nitrophenylphosphate) is the toxic, but non-mutagenic metabolite of the organophosphorus ester (OF) insecticide parathion. Although this agent has been used as a deacetylase inhibitor in many studies, we discovered a mutagenic synergy with paraoxon and plant-activated m-phenylenediamine or with direct-acting 2-acetoxyacetylaminofluorene in Salmonella typhimurium cells [Gichner T. et al. (1996): Environ Mol Mutagen 27; 59-66]. In the present study, mammalian-activated m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, benzidine, 2,3-diaminophenazine or 2-aminofluorene, as well as plant-activated benzidine or 2-aminofluorene expressed an elevated mutagenic potency when assayed with S. typhimurium strain YG1024 in the presence of paraoxon. Under non-toxic conditions, paraoxon amplified the S. typhimurium mutant yield induced by these aromatic amines between 1.9-fold and 8.4-fold. Spectrophotometric analysis demonstrated that the rate of degradation of 2-acetoxyacetyldminofluorene was not significantly different in phosphate buffer with or without paraoxon or with S. typhimurium cytosol with or without paraoxon. Also paraoxon-mediated mutagenic synergy does not appear to be due to a direct reaction with aromatic amines. Mutagenic synergy between aromatic amines and OP oxon products may be a cause of concern because people are chronically exposed to environmental and dietary aromatic amines, and a significant segment of the U.S. population tested positive for OP insecticide residues.

Original languageEnglish (US)
Pages (from-to)312-320
Number of pages9
JournalEnvironmental and Molecular Mutagenesis
Issue number3
StatePublished - Jan 1 1997


  • Arylamines
  • Dielhyl p-nitrophenylphosphate
  • Plant activation
  • Promutagens
  • TX1MX

ASJC Scopus subject areas

  • Epidemiology
  • Genetics(clinical)
  • Health, Toxicology and Mutagenesis

Fingerprint Dive into the research topics of 'Mutagenicity synergy between paraoxon and mammalian or plant-activated aromatic amines'. Together they form a unique fingerprint.

Cite this