Studies on pesticides and related toxicants are designed to evaluate conditions for their safe and effective use, to develop better pesticides with improved selectivity, and to generate fundamental knowledge of general importance for the agricultural, medical and environmental sciences. Insecticide chemistry investigations emphasize synthesis and degradation of neurotoxicants including pyrethroids, isobutylamides and nitromethylene heterocycles and involve the identification and preparation of photoproducts and metabolites and the mechanisms of photodecomposition and photostabilization. Research on the toxicology of neuroactive insecticides considers the aforementioned neurotoxicants plus the polychlorocycloalkanes and trioxabicyclooctanes as to their labile sites and metabolic pathways, bioactivation and detoxification, interactions with antidotes and synergistic toxicants, and mode of action at neurophysiological and receptor levels. The goals in studies on organophosphorus acetylcholinesterase inhibitors are to resolve the chiral toxicants, examine the bioactivity of the individual enantiomers, recognize unusual bioactivation processes, identify the activation and detoxification reactions, and consider possible antidotes. Bicyclophosphorus esters, bicycloorthocarboxylates, polychlorocycloalkanes, and other cyclic or cage convulsants are used to investigate structure-activity relationships in their toxicity to mammals and insects and their potency in disrupting the gamma-aminobutyric acid-A receptor/chloride ionophore complex. Research on novel target sites considers: the binding site for the insecticide ryanodine relative to excitation-contraction coupling and the calcium-regulated calcium channel of the junctional region of the sarcoplasmic reticulum of mammalian muscle; compounds interfering with synthesis of chitin in insects; and herbicides and herbicide antidotes that alter amino acid biosynthesis in plants. Studies on hazardous pesticides focus on toxicants with halogen-, nitrogen-, sulfur- and oxygen-containing toxophoric groups. The goal is to provide a chemical explanation for their mutagenic, carcinogenic and hepatotoxic properties.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Program Projects (P01)
Project #
5P01ES000049-28
Application #
3095769
Study Section
Environmental Health Sciences Review Committee (EHS)
Project Start
1977-12-01
Project End
1992-11-30
Budget Start
1991-12-01
Budget End
1992-11-30
Support Year
28
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of California Berkeley
Department
Type
Schools of Earth Sciences/Natur
DUNS #
094878337
City
Berkeley
State
CA
Country
United States
Zip Code
94704
Casida, John E; Quistad, Gary B (2004) Organophosphate toxicology: safety aspects of nonacetylcholinesterase secondary targets. Chem Res Toxicol 17:983-98
Sparks, S E; Quistad, G B; Li, W et al. (2000) Chloropicrin dechlorination in relation to toxic action. J Biochem Mol Toxicol 14:26-32
Tomizawa, M; Casida, J E (1999) Minor structural changes in nicotinoid insecticides confer differential subtype selectivity for mammalian nicotinic acetylcholine receptors. Br J Pharmacol 127:115-22
Fang, N; Casida, J E (1999) New bioactive flavonoids and stilbenes in cube resin insecticide. J Nat Prod 62:205-10
Sparks, S E; Quistad, G B; Casida, J E (1999) Organophosphorus pesticide-induced butyrylcholinesterase inhibition and potentiation of succinylcholine toxicity in mice. J Biochem Mol Toxicol 13:113-8
Fang, N; Casida, J E (1999) Cube resin insecticide: identification and biological activity of 29 rotenoid constituents. J Agric Food Chem 47:2130-6
Latli, B; D'Amour, K; Casida, J E (1999) Novel and potent 6-chloro-3-pyridinyl ligands for the alpha4beta2 neuronal nicotinic acetylcholine receptor. J Med Chem 42:2227-34
Schneider, M; Quistad, G B; Casida, J E (1999) Glutathione activation of chloropicrin in the Salmonella mutagenicity test. Mutat Res 439:233-8
Staub, R E; Quistad, G B; Casida, J E (1999) S-methyl N-butylthiocarbamate sulfoxide: selective carbamoylating agent for mouse mitochondrial aldehyde dehydrogenase. Biochem Pharmacol 58:1467-73
Schuler, F; Yano, T; Di Bernardo, S et al. (1999) NADH-quinone oxidoreductase: PSST subunit couples electron transfer from iron-sulfur cluster N2 to quinone. Proc Natl Acad Sci U S A 96:4149-53

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