Morten Sandvik

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We have developed a simple and effective method for isolating pectenotoxin-2 (PTX-2) from Dinophysis cells collected from a natural bloom. A two-step extraction procedure followed by two column chromatography steps produced PTX-2 in high purity suitable for use as an analytical standard and for toxicological studies. Incubation of purified PTX-2 with the(More)
Kinetic studies showed that [Asp(3), Dhb(7)]MC-RR reacted with mercaptoethanol hundreds of times more slowly than MC-RR and a range of other [Mdha(7)]-containing microcystin congeners. The difference in reaction rate was sufficiently large that derivatization of microcystin-containing samples with mercaptoethanol, followed by LC-MS analysis, clearly(More)
Marine biotoxins from microalgae can accumulate in shellfish and lead to poisoning of human consumers as well as fish, marine mammals and sea birds. Toxicological assessment of the toxins and development of analytical methods require large amounts of high-purity toxins and their metabolites. Although these toxins can be obtained in limited amounts from(More)
Bivalve molluscs accumulate toxins of the okadaic acid (OA) and pectenotoxin (PTX) groups, which are frequently found in Dinophysis spp. Transformation of the OA-group toxins into fatty acid ester derivatives (often designated "DTX3") is common in many bivalve species but the degree to which these toxins are transformed vary between species, and is also(More)
Okadaic acid analogues are well known as protein phosphatase inhibitors and occur naturally in marine shellfish feeding on dinoflagellates of the genus Dinophysis, leading to diarrhetic shellfish poisoning of shellfish consumers. Knowledge of the correct structures for these toxins is important in understanding their toxicology, biochemistry, and(More)
Responses in flounder (Platichthys flesus) towards benzo [a]pyrene (BaP), 2,3,3',4,4',5-hexachlorobiphenyl (PCB-156), and cadmium (Cd) were investigated in time-course and dose-response studies of selected biomarkers. Measurements of biliary fluorescent BaP metabolites and hepatic concentrations of PCB-156 and cadmium showed that the injected toxicants were(More)
Two novel pectenotoxins (PTXs) were detected by LC-MS in solid phase extracts of net hauls taken at Flødevigen, Norway, in June 2002 that were dominated by Dinophysis acuminata and Dinophysis norvegica. The new compounds were isolated as minor components from a large collection of a Dinophysis acuta-dominated bloom obtained from Skjer, Sognefjorden, Norway,(More)
1. Atrazine (3 daily i.p. doses of 0.20 mg/kg or 10 ppb in the water for 14 days) did not change the xenobiotic metabolizing enzyme activities (XME) towards the substrates aldrin epoxidase (AE), NADPH-cytochrome c reductase (NCCR), 7-ethoxyresorufin O-deethylase (EROD), 1-chloro-2,4-dinitro-benzene (CDNB) and 1,2-dichloro-4-nitrobenzene (DCNB) in trout(More)
The objective of this study was to investigate the response of acetylcholinesterase (AChE) activities in Clarias gariepinus in response to Organophosphates (Ops) and carbamate exposure. The AChE activities were determined in plasma, and eye and brain homogenates of unexposed and exposed fish using Ellman's method and 5,5'-dithiobis-2-nitrobenzoic acid(More)
Passive sampling disks were developed based on the method of MacKenzie, L, Beuzenberg, V., Holland, P., McNabb, P., Selwood, A. [2004. Solid phase adsorption toxin tracking (SPATT): a new monitoring tool that simulates the biotoxin contamination of filter feeding bivalves. Toxicon 44, 901-918] and protocols were formulated for recovering toxins from the(More)