title: Feasibility of gymnodimine and 13-desmethyl C spirolide detection by fluorescence polarization using a receptor-based assay in shellfish matrixes.
abstract: The detection of toxins in shellfish through reliable methods is essential for human health preservation and prevention of economic losses in the aquaculture industry. Although no human intoxication has been unequivocally linked to gymnodimines or spirolides, these phycotoxins are highly toxic by intraperitoneal injection causing false positives in lipophilic toxin detection by the mouse bioassay. Based on the detection of molecular interactions by fluorescence polarization an inhibition assay was developed using fluorescent alpha-bungarotoxin and nicotinic acetylcholine receptor-enriched membranes of Torpedo marmorata to detect gymnodimine and 13-desmethyl C spirolide. Both toxins, classified into the cyclic imine group, inhibit the interaction of alpha-bungarotoxin with Torpedo nicotinic acetylcholine receptors in the nM range. In this study we analyze the matrix effect of four shellfish species on the fluorescence polarization assay. Mussels, clams, cockles and scallops were extracted with acetone and sequentially partitioned with n-hexane and chloroform. The interference of these shellfish extracts with the alpha-bungarotoxin fluorescence or its binding to the nicotinic acetylcholine receptor was lower than 11%. The average recovery rates of gymnodimine and 13-desmethyl C spirolide using these solvents were 90.6+/-7.8% and 89.6+/-3.2%, respectively with variations among species. The quantification range of this fluorescence polarization assay for gymnodimine and 13-desmethyl C spirolide in all tested species was 80-2000 microg kg(-1) and 85-700 microg kg(-1) of shellfish meat, respectively. This assay format can be used to detect gymnodimine and 13-desmethyl C spirolide in shellfish as a screening assay.
authors: Departamento de Farmacología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario, 27002 Lugo, Spain.
authors: Eva S
authors: ES
authors: Fonfría
authors: Natalia
authors: N
authors: Vilariño
authors: Begoña
authors: B
authors: Espiña
authors: M Carmen
authors: MC
authors: Louzao
authors: Mercedes
authors: M
authors: Alvarez
authors: Jordi
authors: J
authors: Molgó
authors: Rómulo
authors: R
authors: Aráoz
authors: Luis M
authors: LM
authors: Botana
mesh_terms: D000818:Animals; D019411:Clinical Laboratory Techniques; D005454:Fluorescence Polarization / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D006575:Heterocyclic Compounds, 3-Ring / Q000032:analysis*; D006844:Hydrocarbons, Cyclic / Q000032:analysis*; D007097:Imines / Q000032:analysis*; D008387:Marine Toxins / Q000032:analysis; D008974:Mollusca; D012758:Shellfish / Q000032:analysis*; D013141:Spiro Compounds / Q000032:analysis*; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: C517170:13-desmethylspirolide C; D006575:Heterocyclic Compounds, 3-Ring; D006844:Hydrocarbons, Cyclic; D007097:Imines; D008387:Marine Toxins; D013141:Spiro Compounds; C407350:gymnodimine