title: Use of engineered enzymes to identify organophosphate and pyrethroid-related toxicity in toxicity identification evaluations.
abstract: Engineered variants of a carboxylesterase from Lucilia cuprina (E3) and a phosphotriesterase from Agrobacterium radiobacter (OpdA) with enhanced hydrolytic activities against pyrethroid and organophosphate pesticides were evaluated as a toxicity identification evaluation (TIE) manipulation. Reduction in toxicity in the presence of the enzyme provides an indication that the toxicant is the enzyme's target substrate. Carboxy/esterase E3 variants were evaluated to determine if the enzymes could mitigate toxicity of pyrethroids to the amphipod, Hyalella azteca. Enzymes were able to achieve 12-70-fold reduction in toxicity for bifenthrin, cyfluthrin, and cypermethrin in water. Only a 2-fold reduction in toxicity was observed with pyrethroid-contaminated sediment though the phosphotriesterase OpdA achieved at least a 35-fold reduction in toxicity from the organophosphate chlorpyrifos in sediment. Tests with urban runoff samples and agriculture-affected sediments demonstrated that the enzymes could be useful in TIEs to identify pesticide-related toxicity. The approach promises to be a useful TIE tool for organophosphate and pyrethroid pesticides, particularly in a water matrix, and potentially could be used for identification of toxicity attributable to other pesticides.
authors.affiliation: Department of Integrative Biology, University of California, 3060 Valley Life Sciences Bldg., Berkeley, California 94720-3140, USA. dweston@berkeley.edu
authors.forename: Donald P
authors.initials: DP
authors.lastname: Weston
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Jackson
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D004798:Enzymes / Q000138:chemical synthesis / Q000235:genetics / Q000378:metabolism; D007306:Insecticides / Q000633:toxicity*; D010755:Organophosphates / Q000633:toxicity*; D015202:Protein Engineering; D011722:Pyrethrins / Q000633:toxicity*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D004798:Enzymes; D007306:Insecticides; D010755:Organophosphates; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; D012710:Serum Albumin, Bovine