title: Organophosphate-resistant forms of acetylcholinesterases in two scallops--the Antarctic Adamussium colbecki and the Mediterranean Pecten jacobaeus.
abstract: We describe the acetylcholinesterase polymorphisms of two bivalve molluscs, Adamussium colbecki and Pecten jacobaeus. The research was aimed to point out differences in the expression of pesticide-resistant acetylcholinesterase forms in organisms living in different ecosystems such as the Ross Sea (Antarctica) and the Mediterranean Sea. In A. colbecki, distinct acetylcholinesterase molecular forms were purified and characterized from spontaneously soluble, low-salt-soluble and low-salt-Triton extracts from adductor muscle and gills. They consist of two non-amphiphilic acetylcholinesterases (G(2), G(4)) and an amphiphilic-phosphatidylinositol-membrane-anchored form (G(2)); a further amphiphilic-low-salt-soluble G(2) acetylcholinesterase was found only in adductor muscle. In the corresponding tissues of P. jacobaeus, we found a non-amphiphilic G(4) and an amphiphilic G(2) acetylcholinesterase; amphiphilic-low-salt-soluble acetylcholinesterases (G(2)) are completely lacking. Such results are related with differences in cell membrane lipid compositions. In both scallops, all non-amphiphilic AChEs are resistant to used pesticides. Differently, the adductor muscle amphiphilic forms are resistant to carbamate eserine and organophosphate diisopropylfluorophosphate, but sensitive to organophoshate azamethiphos. In the gills of P. jacobaeus, amphiphilic G(2) forms are sensitive to all three pesticides, while the corresponding forms of A. colbecki are sensitive to eserine and diisopropylfluorophosphate, but resistant to azamethiphos. Results indicate that organophosphate and/or carbamate resistant AChE forms are present in species living in far different and far away environments. The possibility that these AChE forms could have ensued from a common origin and have been spread globally by migration is discussed.
authors.affiliation: Department of Experimental Medicine, Division of Cellular and Molecular Biology, University of Perugia, Via del Giochetto, I-06122 Perugia, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Romani
authors.forename: Ilaria
authors.initials: I
authors.lastname: Corsi
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonacci
authors.forename: Silvano
authors.initials: S
authors.lastname: Focardi
authors.forename: G Evelina
authors.initials: GE
authors.lastname: De Medio
authors.forename: Alessandra
authors.initials: A
authors.lastname: De Santis
authors.forename: Francesca
authors.initials: F
authors.lastname: Incarnato
authors.forename: Elvio
authors.initials: E
authors.lastname: Giovannini
authors.forename: Gabriella
authors.initials: G
authors.lastname: Rosi
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002499:Centrifugation, Density Gradient; D004351:Drug Resistance; D008522:Mediterranean Sea; D010755:Organophosphates / Q000494:pharmacology*; D049910:Pecten / Q000187:drug effects* / Q000201:enzymology*; D049897:Pectinidae / Q000187:drug effects* / Q000201:enzymology*; D010575:Pesticides / Q000494:pharmacology*; D013045:Species Specificity
chemical_list: D010755:Organophosphates; D010575:Pesticides; D000110:Acetylcholinesterase