title: Joint effects of dimethoate and heavy metals on metabolic responses in a grasshopper (Chorthippus brunneus) from a heavy metals pollution gradient.
abstract: We studied how an exposure to an additional stressing factor-dimethoate, might affect detoxifying ability of grasshoppers collected at 5 meadow sites located along a heavy metal pollution gradient. Activities of esterases and enzymes linked with glutathione (GSH) metabolism were assayed 24 h after topical treatment with 0.32 microg dimethoate per insect. Inhibition of acetylcholinesterase (AChE) reaches nearly 50% of the value stated in untreated insects, without significant site-dependent differences. The pesticide also caused a significant decrease in activities of glutathione peroxidase (GPx) followed by a decrease in GSH levels in grasshoppers from all assayed groups, demonstrating high sensitivity of glutathione-dependent metabolism to the additional stressing factor. In the case of glutathione reductase (GR) and carboxylesterases (CarE) the fall of activity was shown especially in insects from less polluted meadows and the reference site. Glutathione reductase (GR) activity in individuals treated with dimethoate did not decrease only in insects from the most contaminated site I. This might suggest the trade-off mechanisms adapting grasshoppers to life in seriously polluted environments.
authors.affiliation: Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, PL 40-007 Katowice, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Augustyniak
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Babczyńska
authors.forename: Paweł
authors.initials: P
authors.lastname: Migula
authors.forename: Grazyna
authors.initials: G
authors.lastname: Wilczek
authors.forename: Piotr
authors.initials: P
authors.lastname: Łaszczyca
authors.forename: Alina
authors.initials: A
authors.lastname: Kafel
authors.forename: Michał
authors.initials: M
authors.lastname: Augustyniak
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D004117:Dimethoate / Q000633:toxicity*; D005978:Glutathione / Q000032:analysis; D005979:Glutathione Peroxidase / Q000378:metabolism; D006110:Grasshoppers / Q000187:drug effects* / Q000378:metabolism*; D008670:Metals / Q000032:analysis / Q000633:toxicity*; D018515:Plant Leaves / Q000737:chemistry; D006109:Poaceae / Q000737:chemistry; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D008670:Metals; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D000110:Acetylcholinesterase; D005978:Glutathione; D004117:Dimethoate