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  • development of certified reference materials for Diarrhetic Shellfish Poisoning toxins part 2 Shellfish matrix materials
    Journal of AOAC International, 2016
    Co-Authors: Pearse Mccarron, Kelley Reeves, Sabrina D Giddings, Daniel G Beach, Michael A Quilliam
    Abstract:

    Okadaic acid (OA) and its analogs, dinophysistoxins-1 (DTX1) and -2 (DTX2) are lipophilic biotoxins produced by marine algae that can accumulate in Shellfish and cause the human illness known as Diarrhetic Shellfish Poisoning (DSP). Regulatory testing of Shellfish is required to protect consumers and the seafood industry. Certified reference materials (CRMs) are essential for the development, validation, and quality control of analytical methods, and thus play an important role in toxin monitoring. This paper summarizes work on research and development of Shellfish tissue reference materials for OA and DTXs. Preliminary work established the appropriate conditions for production of Shellfish tissue CRMs for OA and DTXs. Source materials, including naturally incurred Shellfish tissue and cultured algae, were screened for their DSP toxins. This preliminary work informed planning and production of a wet mussel (Mytilus edulis) tissue homogenate matrix CRM. The homogeneity and stability of the CRM were evaluated and found to be fit-for-purpose. Extraction and LC-tandem MS methods were developed to accurately certify the concentrations of OA, DTX1, and DTX2 using a combination of standard addition and matrix-matched calibration to compensate for matrix effects in electrospray ionization. The concentration of domoic acid was also certified. Uncertainties were assigned following standards and guidelines from the International Organization for Standardization. The presence of other toxins in the CRM was also assessed and information values are reported for OA and DTX acyl esters.

  • lc ms ms analysis of Diarrhetic Shellfish Poisoning dsp toxins okadaic acid and dinophysistoxin analogues and other lipophilic toxins
    Analytical Sciences, 2011
    Co-Authors: Toshiyuki Suzuki, Michael A Quilliam
    Abstract:

    Diarrhetic Shellfish Poisoning (DSP) is a severe gastrointestinal illness caused by consumption of Shellfish contaminated with DSP toxins that are originally produced by toxic dinoflagellates. Based on their structures, DSP toxins were initially classified into three groups, okadaic acid (OA)/dinophysistoxin (DTX) analogues, pectenotoxins (PTXs), and yessotoxins (YTXs). Because PTXs and YTXs have been subsequently shown to have no Diarrhetic activities, PTXs and YTXs have recently been eliminated from the definition of DSP toxins. Mouse bioassay (MBA), which is the official testing method of DSP in Japan and many countries, also detects PTXs and YTXs, and thus alternative testing methods detecting only OA/DTX analogues are required in DSP monitoring. Electrospray ionization (ESI) liquid chromatography-mass spectrometry (LC-MS) is a very powerful tool for the detection, identification and quantification of DSP and other lipophilic toxins. In the present review, application of ESI LC-MS techniques to the analysis of each toxin group is described.

  • lc ms ms analysis of Diarrhetic Shellfish Poisoning dsp toxins okadaic acid and dinophysistoxin analogues and other lipophilic toxins
    Analytical Sciences, 2011
    Co-Authors: Toshiyuki Suzuki, Michael A Quilliam
    Abstract:

    Diarrhetic Shellfish Poisoning (DSP) is a severe gastrointestinal illness caused by consumption of Shellfish contaminated with DSP toxins that are originally produced by toxic dinoflagellates. Based on their structures, DSP toxins were initially classified into three groups, okadaic acid (OA)/dinophysistoxin (DTX) analogues, pectenotoxins (PTXs), and yessotoxins (YTXs). Because PTXs and YTXs have been subsequently shown to have no Diarrhetic activities, PTXs and YTXs have recently been eliminated from the definition of DSP toxins. Mouse bioassay (MBA), which is the official testing method of DSP in Japan and many countries, also detects PTXs and YTXs, and thus alternative testing methods detecting only OA/DTX analogues are required in DSP monitoring. Electrospray ionization (ESI) liquid chromatography-mass spectrometry (LC-MS) is a very powerful tool for the detection, identification and quantification of DSP and other lipophilic toxins. In the present review, application of ESI LC-MS techniques to the analysis of each toxin group is described.

  • oxidative metabolism by thalassiosira weissflogii bacillariophyceae of a diol ester of okadaic acid the Diarrhetic Shellfish Poisoning
    Journal of Phycology, 2001
    Co-Authors: A. J. Windust, Michael A Quilliam, Jeffrey L C Wright, J. L. Mclachlan
    Abstract:

    Previous investigations into the comparative toxicity of the Diarrhetic Shellfish Poisoning (DSP) toxins to Thalassiosira weissflogii (Grun.) Fryxell et Hasle found that this diatom oxidatively metabolized okadaic acid diol-ester (OA diol-ester) to a more watersoluble product. This oxidative transformation of OA diol-ester by the diatom is significant for two reasons. First, it is known that dinophysistoxin-4 (DTX4), the primary DSP toxin produced by the dinoflagellate Exuviaella lima (Ehr.) Butschli, will be hydrolyzed to the diol-ester following cell rupture (e.g. ingestion by a predator). Second, it implies that the ester, an uncharged, lipophilic intermediate, can easily enter cells and therefore may play an important role in the uptake and transfer of DSP toxins through the food web. It has been suggested that the water soluble DTX-4 may also be the form in which DSP toxins are excreted from the producing cell. Therefore, the stability of DTX-4 was examined when incubated either in fresh seawater medium into which washed cells of E. lima were introduced or in seawater medium conditioned by E. lima cells. Rapid hydrolysis of DTX-4 to the diol-ester took place in both cases. Thus, regardless of the route by which DTX-4 is liberated from the cell, either by cell disruption or excretion, the diol-ester will be the dominant form of the toxin to challenge associated organisms. To examine the metabolism of OA diol-ester by T. weissflogii in more detail, serial cultures of the diatom were challenged with OA diol-ester at a concentration of 2.0 m g·mL 2 1 . The metabolism and fate of the diol-ester in both cellular and medium fractions were monitored over 3 days using liquid chromatography with either ultraviolet (LC-UV) or mass spectrometric (LC-MS) detection. During the course of the experiment, all of the diol-ester was metabolized. LC-MS analysis revealed the presence of multiple oxidative products of OA diol-ester in the medium fraction, including a carboxylic acid derivative. The major metabolites were isolated in sufficient quantity to permit structural elucidation by NMR and MS. All the metabolites identified resulted from oxidation of the diol-ester side chain with the primary sites of attack at the terminal, subterminal, and unsaturated carbons. OA was found in both cellular and medium fractions, and its production was directly correlated with the metabolism of the diol-ester. The relative partitioning of both OA diol-ester and its oxidation products between cells and medium supports the contention that OA diol-ester can readily enter cells, be metabolized, and then excreted in more watersoluble forms.

  • uptake and fate of Diarrhetic Shellfish Poisoning toxins from the dinoflagellate prorocentrum lima in the bay scallop argopecten irradians
    Marine Ecology Progress Series, 2001
    Co-Authors: A G Bauder, Allan Cembella, Monica V Bricelj, Michael A Quilliam
    Abstract:

    Bivalve molluscs can acquire Diarrhetic Shellfish Poisoning (DSP) toxins via ingestion of toxigenic dinoflagellates. The dynamics and fate of DSP toxins were investigated in the bay scallop Argopecten irradians exposed to cells of the epibenthic dinoflagellate Prorocentrum lima, a known producer of DSP toxins, in controlled laboratory microcosms. Toxin parameters determined were uptake and detoxification rates, and anatomical compartmentalization. Toxins in tissue and algal extracts were analyzed by liquid chromatography-mass spectrometry (LC-MS). No mortalities occurred and feeding inhibition was not observed for juvenile and adult bay scallops during the 2 wk exposure to P. lima cells. Clearance rates were similar for scallops exposed to equivalent biovolume cell concentrations of toxigenic P. lima and the non-toxic diatom Thalassiosira weissflogii; however, absorption efficiency of organic matter was significantly lower with a diet of P. lima than T. weissflogii. Although DSP toxin concentrations in viscera of bay scallop exceeded commonly accepted regulatory levels (0.2 μg g -1 whole tissue) within 24 h of exposure to P. lima, after 2 wk of exposure total DSP toxin retained in scallop tissues was <1 % of the total toxin ingested over the same period. Most of the total toxin body burden was in the viscera (76%); however, in adult scallops a significant portion was associated with gonadal tissue (12%). Toxin levels were relatively low in gill, mantle and adductor tissue (<12% of total toxin body burden). During the depuration period, rapid release of DSP toxins from scallops indicated that toxins were poorly bound to all tissues, with the exception of the viscera. Detoxification of viscera consisted of a rapid loss of weakly bound toxin components within the initial 3 d of depuration, followed by a much slower release of the remaining toxin at a rate of 8.4 % d -1 .

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  • kinetics of Diarrhetic Shellfish Poisoning toxins okadaic acid dinophysistoxin 1 pectenotoxin 6 and yessotoxin in scallops patinopecten yessoensis
    Fisheries Science, 2005
    Co-Authors: Toshiyuki Suzuki, Tomoji Igarashi, Kazuhiko Ichimi, Masatoshi Watai, Megumi Suzuki, Eri Ogiso, Takeshi Yasumoto
    Abstract:

    Four toxins, okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-6 (PTX6), and yessotoxin (YTX), all associated with Diarrhetic Shellfish Poisoning (DSP), were administered via syringe to Scallops Patinopecten yessoensis and their distribution in the hepatopancreas, adductor muscle, and combined other tissues (mantle, gill, gonad) was analyzed by liquid chromatography-mass spectrometry. Toxins exclusively remained in the hepatopancreas irrespective of the injection site, adductor muscle or hepatopancreas. When injected into hepatopancreas, OA, DTX1, and YTX were metabolized to 7-O-palmitoylOA, 7-O-palmitoylDTX1 and 45-hydroxyyessotoxin (45OH-YTX), respectively. Such metabolic changes were insignificant when toxins were injected into the adductor muscle. The residual ratio for each toxin in the hepatopancreas was less than 20%. Mortalities of scallops treated with PTX6 were lower than those treated with other toxins.

  • chemistry etiology and food chain dynamics of marine toxins
    Proceedings of the Japan Academy. Series B Physical and biological sciences, 2005
    Co-Authors: Takeshi Yasumoto
    Abstract:

    Highly complex chemical structures of marine natural toxins involved in seafood Poisoning were determined using small samples. The biogenetic process by which the toxins accumulate in fish and Shellfish was explained by the food chain. The primary sources of the toxins were identified as dinoflagellates, bacteria, and blue-green algae. The topics related to ciguatera, puffer fish, Diarrhetic Shellfish Poisoning, neurotoxic Shellfish Poisoning, azaspiracid Poisoning, red tides, and Gracilaria red alga Poisoning are described. (Communicated by Saburo TAMURA, M.J.A.)

  • quantitative determination of marine toxins associated with Diarrhetic Shellfish Poisoning by liquid chromatography coupled with mass spectrometry
    Journal of Chromatography A, 2001
    Co-Authors: Hirofumi Goto, Tomoji Igarashi, Masatoshi Watai, Megumi Yamamoto, Manami Yasuda, Reiji Sekiguchi, Kenji Tanno, Takeshi Yasumoto
    Abstract:

    Quantitative determination by liquid chromatography (LC) coupled with mass spectrometry (MS) was achieved for the following 10 toxins found in association with Diarrhetic Shellfish Poisoning: okadaic acid (OA), dinophysistoxin-1 (DTX1), 7-O-palmitoylokadaic acid (palOA), 7-O-palmitoyldinophysistoxin-1 (palDTX1), pectenotoxin-1 (PTX1), pectenotoxin-2 (PTX2), pectenotoxin-2 seco acid (PTX2SA), pectenotoxin-6 (PTX6), yessotoxin (YTX), and 45-hydroxyyessotoxin (YTXOH). Toxins in 2 g of the adductor muscle or the digestive glands of scallops, Patinopecten yessoensis, were extracted with 18 ml of methanol–water (9:1, v/v), freed of polar contaminants by partition between chloroform and water, and treated by solid-phase extraction on a silica cartridge column. Samples containing YTXOH were purified separately on a buffered reversed-phase column. Chromatographic separation was achieved by the following combinations of columns and mobile phases: a Symmetry C18 column with acetonitrile–0.05% acetic acid (7:3, v/v) for OA, DTX1, PTX6 and PTX2SA; a Develosil ODS column with the same mobile phase for PTX1 and PTX2; a Capcellpak column with methanol–2.5% acetic acid (98:2, v/v) for palOA and palDTX1; and an Inertsil ODS column with methanol–0.2 M ammonium acetate (8:2, v/v) for YTX and YTXOH. Carboxylic acid toxins were selectively monitored on [M−H]− ions, sulfated toxins on [M−Na]− ions, and neutral toxins on [M+NH4]+ ions. Average recoveries of the toxins spiked to tissue homogenates ranged from 70 to 134%. Detection limits in the muscle ranged from 5 to 40 ng/g and those in the digestive glands from 10 to 80 ng/g.

  • liquid chromatography electrospray ionization mass spectrometry of the Diarrhetic Shellfish Poisoning toxins okadaic acid dinophysistoxin 1 and pectenotoxin 6 in bivalves
    Journal of Chromatography A, 2000
    Co-Authors: Toshiyuki Suzuki, Takeshi Yasumoto
    Abstract:

    Determination of Diarrhetic Shellfish-Poisoning (DSP) toxins, okadaic acid (OA), dinophysistoxin-1 (DTX1) and pectenotoxin-6 (PTX6) was carried out by liquid chromatography (LC) followed by on-line atmospheric pressure electrospray ionization-mass spectrometric (ESI-MS) detection with a heated capillary interface. Mass spectra of authentic OA, DTXI and PTX6 standards exhibited abundant [M-H] at m/z 803, 817 and 887, respectively. Linearity of peak area obtained by selected-ion monitoring (SIM) for [M-H]- of each toxin was confirmed over a wide range of concentrations from 10 pg to 30 ng. LC-ESI-MS analysis of OA, DTX1 and PTX6 in scallops and mussels, collected at the same site (Mutsu Bay, Japan), was carried out. Scallops and mussels collected at the same site showed different toxin profiles. Although PTX6 was detected from scallops, it was not detected from mussels.

  • identification and characterization of pectenotoxin ptx 4 and ptx7 as spiroketal stereoisomers of two previously reported pectenotoxins
    Journal of Organic Chemistry, 1998
    Co-Authors: Kazuo Sasaki, Jeffrey L C Wright, Takeshi Yasumoto
    Abstract:

    Pectenotoxins (PTXs) isolated from the scallop Patinopecten yessoensis were shown to be involved in an episode of Diarrhetic Shellfish Poisoning (DSP). A total of eight analogues (PTX1−PTX7 and PTX10) have been isolated to date, and the structures of four of these analogues (PTX1, PTX2, PTX3, and PTX6) have already been elucidated. Here, we report the characterization of PTX4 and PTX7 as 7-epi-PTX1 and 7-epi-PTX6, respectively, on the basis of NMR data and an acid-catalyzed chemical interconversion. The structures of two new artifacts, PTX8 and PTX9, produced following this treatment are also reported.

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  • sulfated diesters of okadaic acid and dtx 1 self protective precursors of Diarrhetic Shellfish Poisoning dsp toxins
    Harmful Algae, 2017
    Co-Authors: Patricia Leblanc, Pearse Mccarron, Jeffrey L C Wright, Ian W Burton, John A Walter, Jeremy E Melanson, Wendy K Strangman
    Abstract:

    Many toxic secondary metabolites used for defense are also toxic to the producing organism. One important way to circumvent toxicity is to store the toxin as an inactive precursor. Several sulfated diesters of the Diarrhetic Shellfish Poisoning (DSP) toxin okadaic acid have been reported from cultures of various dinoflagellate species belonging to the genus Prorocentrum. It has been proposed that these sulfated diesters are a means of toxin storage within the dinoflagellate cell, and that a putative enzyme mediated two-step hydrolysis of sulfated diesters such as DTX-4 and DTX-5 initially leads to the formation of diol esters and ultimately to the release of free okadaic acid. However, only one diol ester and no sulfated diesters of DTX-1, a closely related DSP toxin, have been isolated leading some to speculate that this toxin is not stored as a sulfated diester and is processed by some other means. DSP components in organic extracts of two large scale Prorocentrum lima laboratory cultures have been investigated. In addition to the usual suite of okadaic acid esters, as well as the free acids okadaic acid and DTX-1, a group of corresponding diol- and sulfated diesters of both okadaic acid and DTX-1 have now been isolated and structurally characterized, confirming that both okadaic acid and DTX-1 are initially formed in the dinoflagellate cell as the non-toxic sulfated diesters.

  • oxidative metabolism by thalassiosira weissflogii bacillariophyceae of a diol ester of okadaic acid the Diarrhetic Shellfish Poisoning
    Journal of Phycology, 2001
    Co-Authors: A. J. Windust, Michael A Quilliam, Jeffrey L C Wright, J. L. Mclachlan
    Abstract:

    Previous investigations into the comparative toxicity of the Diarrhetic Shellfish Poisoning (DSP) toxins to Thalassiosira weissflogii (Grun.) Fryxell et Hasle found that this diatom oxidatively metabolized okadaic acid diol-ester (OA diol-ester) to a more watersoluble product. This oxidative transformation of OA diol-ester by the diatom is significant for two reasons. First, it is known that dinophysistoxin-4 (DTX4), the primary DSP toxin produced by the dinoflagellate Exuviaella lima (Ehr.) Butschli, will be hydrolyzed to the diol-ester following cell rupture (e.g. ingestion by a predator). Second, it implies that the ester, an uncharged, lipophilic intermediate, can easily enter cells and therefore may play an important role in the uptake and transfer of DSP toxins through the food web. It has been suggested that the water soluble DTX-4 may also be the form in which DSP toxins are excreted from the producing cell. Therefore, the stability of DTX-4 was examined when incubated either in fresh seawater medium into which washed cells of E. lima were introduced or in seawater medium conditioned by E. lima cells. Rapid hydrolysis of DTX-4 to the diol-ester took place in both cases. Thus, regardless of the route by which DTX-4 is liberated from the cell, either by cell disruption or excretion, the diol-ester will be the dominant form of the toxin to challenge associated organisms. To examine the metabolism of OA diol-ester by T. weissflogii in more detail, serial cultures of the diatom were challenged with OA diol-ester at a concentration of 2.0 m g·mL 2 1 . The metabolism and fate of the diol-ester in both cellular and medium fractions were monitored over 3 days using liquid chromatography with either ultraviolet (LC-UV) or mass spectrometric (LC-MS) detection. During the course of the experiment, all of the diol-ester was metabolized. LC-MS analysis revealed the presence of multiple oxidative products of OA diol-ester in the medium fraction, including a carboxylic acid derivative. The major metabolites were isolated in sufficient quantity to permit structural elucidation by NMR and MS. All the metabolites identified resulted from oxidation of the diol-ester side chain with the primary sites of attack at the terminal, subterminal, and unsaturated carbons. OA was found in both cellular and medium fractions, and its production was directly correlated with the metabolism of the diol-ester. The relative partitioning of both OA diol-ester and its oxidation products between cells and medium supports the contention that OA diol-ester can readily enter cells, be metabolized, and then excreted in more watersoluble forms.

  • identification and characterization of pectenotoxin ptx 4 and ptx7 as spiroketal stereoisomers of two previously reported pectenotoxins
    Journal of Organic Chemistry, 1998
    Co-Authors: Kazuo Sasaki, Jeffrey L C Wright, Takeshi Yasumoto
    Abstract:

    Pectenotoxins (PTXs) isolated from the scallop Patinopecten yessoensis were shown to be involved in an episode of Diarrhetic Shellfish Poisoning (DSP). A total of eight analogues (PTX1−PTX7 and PTX10) have been isolated to date, and the structures of four of these analogues (PTX1, PTX2, PTX3, and PTX6) have already been elucidated. Here, we report the characterization of PTX4 and PTX7 as 7-epi-PTX1 and 7-epi-PTX6, respectively, on the basis of NMR data and an acid-catalyzed chemical interconversion. The structures of two new artifacts, PTX8 and PTX9, produced following this treatment are also reported.

  • detection of new 7 o acyl derivatives of Diarrhetic Shellfish Poisoning toxins by liquid chromatography mass spectrometry
    Toxicon, 1992
    Co-Authors: J C Marr, Michael A Quilliam, Stephen Pleasance, Jeffrey L C Wright
    Abstract:

    A novel method for the detection of acylated Diarrhetic Shellfish Poisoning toxins is reported. Direct determination of these compounds is possible using high performance liquid chromatography coupled with ion-spray mass spectrometry. An extract, purified from the digestive glands of toxic mussels (Mytilus edulis) contaminated with okadaic acid, dinophysistoxin-1, and a recently reported analog, dinophysistoxin-2, was also shown to contain small amounts of dinophysistoxin-3, a mixture of 7-O-acyl ester derivatives of dinophysistoxin-1. In addition, acyl ester derivatives of okadaic acid and dinophysistoxin-2 were also detected by direct LC-MS analysis and confirmed by analysis of their hydrolysis products. This is the first report of the detection of other naturally occurring 7-O-acyl esters similar to dinophysistoxin-3.