Evaluation of the fluorometric protein phosphatase inhibition assay in the determination of okadaic acid in mussels

Mountfort, Douglas O.; Kennedy, Glenn; Garthwaite, Ian; Quilliam, Michael A.; Truman, Penelope; Hannah, Donald J.

doi:10.1016/s0041-0101(98)00222-0

Cited by 49 publications

(16 citation statements)

References 10 publications

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“…Suzuki and Mitsuya (2001) reported for the same two species DTX1 ester percentages of 17 and 34% in two samples and in two samples of scallop DTX1 ester percentages of 90-100%. Mountfort et al (1999) reported for New Zealand blue mussels (M. edulis) that esters did not surpass half of the total OA equivalents found, and in samples of green mussels (Perna canaliculus), the content of esters was 80-90% of total OA equivalents. MacKenzie et al (2002) reported for greenshell mussels (Perna canaliculus) 79-100% of the total OA as esters.…”

Section: Introductionmentioning

confidence: 92%

Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

Jørgensen¹,

Scanlon²,

Jensen³

2005

Food Additives and Contaminants

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Until recently, little focus was given to the presence of diarrhetic shellfish poisoning (DSP) toxin esters in seafood products. However, during the last few years, the occurrence of a high percentage of esters of the total amount of DSP toxins present in some seafood products has been observed. Samples of Danish surf clams (Spisola spp.) and blue mussels (Mytilus edulis) from 1999-2004 were analysed by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) for the presence of DSP toxin esters. The samples contained only okadaic acid and esters of okadaic acid. The level of total okadaic acid equivalents ranged from 224 to 2516 microg kg-1 in surf clams. The percentage of okadaic acid esters of the total okadaic acid equivalents ranged from 83 to 98%, mean 95%. The level of total okadaic acid equivalents ranged from 43 to 1631 microg kg-1 in blue mussels. The percentage of okadaic acid esters of the total okadaic acid equivalents ranged from 21 to 86%, mean 59%. The probability of a high percentage of okadaic acid esters seems to increase with higher amounts of total okadaic acid equivalents in the bivalves. The large prevalence of DSP toxin esters are of particular importance because of the increased use of chemical methods instead of mouse bioassay for the detection of DSP toxicity.

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Section: Introductionmentioning

confidence: 92%

Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

Jørgensen¹,

Scanlon²,

Jensen³

2005

Food Additives and Contaminants

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“…Several PP inhibition assays (PPIA), using different phosphatase sources and colorimetric or fluorimetric substrates, have been developed [316,317,318,319,320,321]. Recently, a colorimetric PPIA, OkaTest, has been interlaboratory-validated for quantification of the OA toxin group in molluscs [322], and it could be also applied for Dinophysis cell samples.…”

Section: Assessment Of Sample Collection Procedures and Available mentioning

confidence: 99%

Dinophysis Toxins: Causative Organisms, Distribution and Fate in Shellfish

et al. 2014

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Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<103 cells·L−1). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

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“…There are numerous descriptions of the application of protein phosphatase inhibition assays for determination of OA and its derivatives [7,8,9,10,11,12,13]. However, the inhibition pattern of OA, DTX1 and DTX2 is different and is supposed to correspond to their toxicity.…”

Section: Resultsmentioning

confidence: 99%

“…Different laboratories have developed in-house PPIA with good qualifications, using colorimetric or fluorimetric substrates to monitor enzyme inhibition. [7,8,9,10,11,12]. A collaborative study was also performed with a fluorimetric assay [13].…”

Section: Introductionmentioning

confidence: 99%

Single Laboratory Validation of A Ready-to-Use Phosphatase Inhibition Assay for Detection of Okadaic Acid Toxins

Smienk¹,

Calvo²,

Razquín³

et al. 2012

Toxins

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A phosphatase inhibition assay for detection of okadaic acid (OA) toxins in shellfish, OkaTest, was single laboratory validated according to international recognized guidelines (AOAC, EURACHEM). Special emphasis was placed on the ruggedness of the method and stability of the components. All reagents were stable for more than 6 months and the method was highly robust under normal laboratory conditions. The limit of detection and quantification were 44 and 56 µg/kg, respectively; both below the European legal limit of 160 µg/kg. The repeatability was evaluated with 2 naturally contaminated samples. The relative standard deviation (RSD) calculated was 1.4% at a level of 276 µg/kg and 3.9% at 124 µg/kg. Intermediate precision was estimated by testing 10 different samples (mussel and scallop) on three different days and ranged between 2.4 and 9.5%. The IC50 values of the phosphatase used in this assay were determined for OA (1.2 nM), DTX-1 (1.6 nM) and DTX-2 (1.2 nM). The accuracy of the method was estimated by recovery testing for OA (mussel, 78–101%; king scallop, 98–114%), DTX-1 (king scallop, 79–102%) and DTX-2 (king scallop, 93%). Finally, the method was qualitatively compared to the mouse bioassay and LC-MS/MS.

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Evaluation of the fluorometric protein phosphatase inhibition assay in the determination of okadaic acid in mussels

Cited by 49 publications

References 10 publications

Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

Diarrhetic shellfish poisoning toxin esters in Danish blue mussels and surf clams

Dinophysis Toxins: Causative Organisms, Distribution and Fate in Shellfish

Single Laboratory Validation of A Ready-to-Use Phosphatase Inhibition Assay for Detection of Okadaic Acid Toxins

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