title: A protein phosphatase 2A inhibition assay for a fast and sensitive assessment of okadaic acid contamination in mussels.
abstract: The specific inhibitory activity exerted by okadaic acid on protein phosphatase 2A was used to assess the presence of okadaic acid in mussels, using a commercially available protein phosphatase 2A preparation. Under the conditions used, okadaic acid inhibits the enzymatic activity dose-dependently, with an IC50 = 0.26 ng/ml (0.32 nM). The assay is accurate and reproducible. Okadaic acid was detected in concentrations as low as 0.063 ng/ml in aqueous solutions and 2 ng/g in mussel digestive glands. Thirty naturally contaminated mussel samples were submitted to the protein phosphatase 2A inhibition assay as well as to an ELISA assay and to a MTT cytotoxicity assay, with similar results. The proposed assay is sensitive, rapid and does not require expensive equipment. These characteristics make it a good candidate for employment in the routine assessment of okadaic acid shellfish contamination.
authors.affiliation: Dipartimento di Scienze Biomediche, Università di Trieste, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Tubaro
authors.forename: C
authors.initials: C
authors.lastname: Florio
authors.forename: E
authors.initials: E
authors.lastname: Luxich
authors.forename: S
authors.initials: S
authors.lastname: Sosa
authors.forename: R
authors.initials: R
authors.lastname: Della Loggia
authors.forename: T
authors.initials: T
authors.lastname: Yasumoto
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000378:metabolism*; D002273:Carcinogens / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D004396:Coloring Agents / Q000737:chemistry; D004064:Digestive System / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000633:toxicity*; D004797:Enzyme-Linked Immunosorbent Assay; D005506:Food Contamination; D007928:Lethal Dose 50; D019319:Okadaic Acid / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D054648:Protein Phosphatase 2; D015203:Reproducibility of Results; D012758:Shellfish; D013778:Tetrazolium Salts / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
chemical_list: D002273:Carcinogens; D004396:Coloring Agents; D004791:Enzyme Inhibitors; D013778:Tetrazolium Salts; D013844:Thiazoles; D014874:Water Pollutants, Chemical; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; C022616:thiazolyl blue