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PubMed1993

Analysis of paralytic shellfish poisoning toxins by automated pre-column oxidation and microcolumn liquid chromatography with fluorescence detection.

Periodate oxidation of the toxins responsible for paralytic shellfish poisoning (PSP) yields fluorescent purines suitable for trace analysis by reversed-phase LC. Mobile phases containing perfluorinated acids, such as heptafluorobutyric acid, as ion-pair agents were found to provide high capacity factors for the oxidized products. Gradient elution on a microbore column with large volume injections and fluorescence detection permitted the detection of femtomole quantities of PSP toxins. A fully automated pre-column oxidation procedure was developed for an LC autosampler system in order to improve precision and allow unattended analyses. The complete method was applied successfully to various samples, including shellfish and toxic phytoplankton.

Autoanalysis↗

PubMed1989

Paralytic shellfish poisoning in northwest Spain: the toxicity of the dinoflagellate Gymnodinium catenatum.

The highly productive mussel fishery in the Rias Bajas region of northwest Spain has experienced several outbreaks of paralytic shellfish poisoning (PSP) beginning in 1976. In this study, similarities in the HPLC analyses of extracts from toxic shellfish, plankton tows and cultured dinoflagellates from the Rias Vigo and Pontevedra clearly indicate that Gymnodinium catenatum Graham is the organism responsible for recent PSP episodes. The toxin profile of the dinoflagellate contains an unusually high proportion of the low potency sulfocarbamoyl toxins (ca. 90-95 mole %), although a major portion of the overall toxicity is due to the more potent saxitoxin that is present at 5-10% of the total. Toxin profiles of shellfish showed approximately the same composition as that of the dinoflagellate, although the shellfish contained several carbamate toxins (GTX I, GTX II, GTX IV and NEO) that were not detected in G. catenatum culture extracts. The shellfish also contained decarbamoyl toxins (dc-GTX II and dc-GTX-III) at approximately 2% of the total profile. Since these were not detected in the dinoflagellate, their presence reflects either chemical or enzymatic conversion within the shellfish.

Animals↗

PubMed1998

Improved method for preparation and use of 9-anthryldiazomethane for derivatization of hydroxycarboxylic acids. Application to diarrhetic shellfish poisoning toxins.

Application of a method for the "in situ" generation of 9-anthryldiazomethane (ADAM) to the derivatization of the carboxyl function in diarrhetic shellfish poisoning (DSP) toxins revealed the formation of artifact products. Using liquid chromatography-mass spectrometry, it was determined that these artifacts were due to base-catalyzed reactions between the solvent, ethyl acetate, and the hydroxyl groups of the analyte to produce O-acetylated ADAM derivatives. Using a new formulation, with tetrahydrofuran as solvent, it was possible to eliminate these artifact reactions. Various reaction parameters have also been re-optimized to ensure quantitative derivatizations. An assessment method was developed that was useful not only for optimizing reaction parameters, but also for evaluating the reagent potency before use on important samples. Finally, application of the method to the determination of DSP toxins in plankton and mussel tissue was demonstrated.

Anthracenes↗

PubMed2004

Analysis of paralytic shellfish poisoning toxin congeners by a sodium channel receptor binding assay.

This study was carried out to characterize the detection and quantitation of several paralytic shellfish poisoning (PSP) toxin congeners using a receptor binding assay (RBA). This involved competitive binding of the toxin congeners against tritium-labeled STX for receptor sites on rat brain sodium channels. Competitive binding curves were described by a four-parameter logistic equation. Half-saturation values (EC(50)) ranged from 4.38 nM for STX to 142 nM for GTX5. Receptor binding affinity was in the order STX>GTX1/4>neoSTX>GTX2/3>dcSTX>GTX5, and this was similar to the order of mouse toxicity of these congeners. Predicted toxin concentrations from observed STXeq values and EC(50) ratios relative to STX were within 20% or better of the actual concentrations used in the assay. In contrast predicted toxin concentrations using mouse toxicity ratios relative to STX did not provide a good match to actual concentrations, except for GTX1/4. This study has shown that the rat brain sodium channel RBA will provide a reliable integration of total toxicity of various PSP toxin congeners present in a sample.

Animals↗

PubMed2006

[Lipophilic toxin profiles associated with diarrhetic shellfish poisoning in scallops, Patinopecten yessoensis, collected in Hokkaido and comparison of the quantitative results between LC/MS and mouse bioassay].

Lipophilic toxins associated with diarrhetic shellfish poisoning (DSP) in scallops, Patinopecten yessoensis, collected in Hokkaido, Japan were quantified by liquid chromatography-mass spectrometry (LC/MS). Pectenotoxin-6 (PTX6) and yessotoxin (YTX) were the dominant toxins in the scallops, although the percentages of these toxins were different depending on the production area or the sampling period. The quantitative results obtained for the scallops in LC/MS and in mouse bioassay (MBA) were compared. Fifty of the 55 samples found to be exceeding the local quarantine level (0.025 MU/g whole meat) in Hokkaido by LC/MS were quantified by MBA as being below the quarantine level. It is suggested that this discrepancy is due to poor detection of YTX by MBA. These results indicate that LC/MS is a better method than MBA in terms of sensitivity and accuracy to quantify known lipophilic toxins, including YTX.

Animals↗

PubMed1991

Analysis of paralytic shellfish poisons by capillary electrophoresis.

A capillary electrophoresis (CE) method with UV detection is described for the separation and determination of underivatized toxins associated with paralytic shellfish poisoning (PSP). Confirmation of the electrophoretic peaks was facilitated by mass spectrometric (MS) detection using an ionspray CE-MS interface and by high-performance liquid chromatography with fluorescence detection. The determination of PSP toxins, such as saxitoxin and neosaxitoxin, in toxic dinoflagellates and scallops is demonstrated and comparisons are made with existing techniques.

Animals↗

PubMed2000

Development and validation of a high-performance liquid chromatographic method using fluorimetric detection for the determination of the diarrhetic shellfish poisoning toxin okadaic acid without chlorinated solvents.

A modification of the high-performance liquid chromatographic method with fluorimetric detection method for the determination of diarrhetic shellfish poisoning toxins was developed to completely avoid the use of dangerous chlorinated solvents. The method was validated for the toxin okadaic acid (OA) over a period of 6 months where 12 calibrations were performed and 72 samples were analyzed. Analysis of toxic and non-toxic mussels, clams and scallops demonstrated its selectivity. Linearity was observed in the tested range of interest for monitoring purposes of edible shellfish, from the limit of detection (0.3 microg OA/g hepatopancreas) to 13 microg OA/g hepatopancreas. Intra-assay precision of the method was 7% RSD at the quantification limit (0.97 microg OA/g hepatopancreas at S/N=10). Accuracy was tested in triplicate recovery experiments from OA-spiked shellfish where recovery ranged from 92 to 106% in the concentration range of 0.8 to 3.6 microg OA/g hepatopancreas. Useful information on critical factors affecting calibration and reproducibility is also reported. Good correlation (R=0.87) was observed between the results of the method and those of the method of Lee, after the analysis of 45 samples of mussels from the galician rias.

Calibration↗

PubMed2005

Paralytic shellfish poison (PSP) profiles and toxification of short-necked clams fed with the toxic dinoflagellate Alexandrium tamarense.

As a part of our studies on paralytic shellfish poison (PSP) accumulation kinetics in bivalves, short-necked clam Tapes japonia was experimentally contaminated with PSP by being fed with the toxic dinoflagellate Alexandrium tamarense for 2, 4, 6, 8 and 10 days, and the processes of PSP accumulation and bioconversion were investigated: the toxicity level was determined by mouse bioassay and toxin components were identified by high-performance liquid chromatography (HPLC). The strain of A. tamarense used in this study possessed a specific toxicity of 186.7 +/- 81 (mean +/- S.D., n = 5) x 10(-6) MU/cell. Total toxin concentration of this strain was 140.4 +/- 61 (mean S.D., n = 5) fmol/cell. The toxicity level of short-necked clams increased almost in parallel with the abundance of A. tamarense, reaching 1.8, 3.2, 3.8, 3.5 and 4.6 MU/g meat for 2, 4, 6, 8 and 10 days of feeding, respectively. The accumulation rates of PSP toxins, which are the ratio of the total amount of toxins accumulated in the bivalves to the estimated intake in each feeding experiment, were 7.5, 8.1, 5.7, 4.2 and 4.4% for 2, 4, 6, 8 and 10 days, respectively. At the end of each exposure period, many undigested algal cells were found in pseudofeces under microscopic observation. There was a remarkable difference in the relative proportions of the predominant toxin components between A. tamarense and short-necked clams. The most notable difference was the change in the relative amounts of C2 (carbamoyl-N-sulfo-11beta-hydroxysaxitoxin sulfate), GTX1 and GTX 4 during the first two days. In the toxic bivalves, the amount of C2, which is dominant in A. tamarense, decreased to below half a percent after being ingested. Subsequently, the amount of GTX1 in the shellfish meat reached 50.1 mol%, while that of GTX4 decreased to about half of that in A. tamarense. As for the configuration of 11-hydroxysulfate, PSP components in A. tamarense exist almost exclusively as beta-epimers (GTX3, GTX4, C2 and C4), accounting for 72.8 mol% of the total. This contrasts with the case of the short-necked clams, where the beta-epimers represented 25.8, 33.8, 30.8, 36.8 and 28.5 mol% of the total after 2, 4, 6, 8 and 10 days, respectively. PSP components seemed to be converted rapidly at an early stage of the feeding of A. tamarense.

Animals↗

PubMed2003

Implication of brevetoxin B1 and PbTx-3 in neurotoxic shellfish poisoning in New Zealand by isolation and quantitative determination with liquid chromatography-tandem mass spectrometry.

Brevetoxin B1 (BTX-B1) was isolated from Austrovenus stutchburyi following the 1992-1993 outbreak of neurotoxic shellfish poisoning (NSP) in New Zealand. We report here the first isolation of PbTx-3 from the same shellfish and the development of a procedure for quantitative determination of PbTx-3 and BTX-B1. PbTx-3 was isolated by chromatography on columns of SiO2, ODS, and LH-20, followed by reverse-phase HPLCs. In mass spectrometry (MS) with an electrospray ionization (ESI) interface operating in the positive or negative ion mode, the abundant protonated ion [M+H]+ of PbTx-3 (m/z 897) and the de-sodiated ion [M-Na]- of BTX-B1 (m/z 1016) were generated, respectively. These served as precursor ions for collision-induced dissociation, and the product ions of m/z 725 from PbTx-3 and m/z 80 from BTX-B1 were identified, allowing unambiguous confirmation of these toxins by selected reaction monitoring liquid chromatography-tandem mass spectrometry (SRM LC-MS/MS) analysis. The determination limits were 0.4 and 2 ng/g for BTX-B1 and PbTx-3 at a signal-to-noise ratio of five, respectively. This LC-MS/MS method was successfully applied to determine BTX-B1 and PbTx-3 in the NSP-associated toxic shellfish. BTX-B1 was found in both A. stutchburyi and Perna canaliculus, but not in Crassostrea gigas, while PbTx-3 was found in all three.

Animals↗

PubMed1995

Bioaccumulation of paralytic shellfish poisoning (PSP) toxins from the cyanobacterium Anabaena circinalis by the freshwater mussel Alathyria condola.

The Australian freshwater mussel Alathyria condola accumulated high levels of paralytic shellfish poisoning (PSP) toxins when fed the neurotoxic cyanobacterium Anabaena circinalis, shown recently to contain high concentrations of C-toxins and gonyautoxins. Significant accumulation (>80 mu g/100 g of mussel flesh) was detected following 2-3 exposure to water containing 2 x 105 cells/ml A. circinalis. Only trace accumulation of PSP toxins was demonstrated over long-term (5 week) exposure at low concentration (c. 104 cells/ml). The relative abundance of C-toxins, gonyautoxins and saxitoxins in mussels generally matched the toxin profiles of the dietary A. circinalis, although there were differences in the GTX2/3 and C1/2 ratios with time, and an increase in abundance of decarbamoylgonyautoxins. Analysis of mussel tissues after 7 days, exposure to A. circinalis revealed that 96% of the toxins were accumulated in the viscera. As in marine waters, the bioaccumulation of PSP toxins in freshwater mussels may pose a health risk to humans and animals, especially in areas where seasonally decreasing water levels expose mussel beds to surface scums of toxic cyanobacteria.

Anabaena↗

PubMed1994

Diarrhetic shellfish poison in mussels: comparison of methods of detection and determination of the effectiveness of depuration.

The lack of specificity of the Yasumoto mouse bioassay for Diarrhetic Shellfish Poisoning (DSP) toxin and the possibility of obtaining false positive results, prompted a search for a suitable method to confirm doubtful results. The mouse bioassay, an enzyme-linked immunoassay (ELISA) and a tissue culture bioassay were compared; in addition the efficiency of depuration of toxic mussels in ozonized water was evaluated. DSP assay using tissue cultures was found suitable for confirming results obtained using the mouse bioassay, particularly where interpretation was difficult. The ELISA kit gave satisfactory results, but it responded only to okadaic acid and dinophysistoxin 1. Depuration reduced toxicity in some cases after 3 days of treatment.

Animals↗

PubMed1997

Comparative toxicity of the diarrhetic shellfish poisons, okadaic acid, okadaic acid diol-ester and dinophysistoxin-4, to the diatom Thalassiosira weissflogii.

Quantitative structure-activity relationships were determined for the diarrhetic shellfish poisoning (DSP) toxins, okadaic acid (OA), OA diol-ester and dinophysistoxin-4 (DTX-4), using a sensitive bioassay procedure with the diatom Thalassiosira weissflogii. OA diol-ester was found to be nearly as toxic as OA. This result contradicted the accepted idea that only the free acid toxins, such as DTX-1 and OA, are potent phosphatase inhibitors. Postassay analyses using liquid chromatography-mass spectrometry (LC-MS) of cultures incubated with OA diol-ester showed that the ester had partially decomposed to OA, which explained some but not all of the observed toxicity. The formation of OA during the bioassay raised the possibility that cells exposed to inactive DSP toxin esters could metabolically activate them. This was examined in an additional experiment which showed that the hydrolysis of both DTX-4 and OA diol-ester was spontaneous and apparently not mediated by the presence of T. weissflogii cells. However, cells of T. weissflogii challenged with OA diol-ester rapidly metabolized most of the toxin to a more water-soluble product. From interpretation of mass spectral data obtained using ion-spray LC-MS, the metabolite was identified as an oxygenated diol-ester of OA, implying that it was the product of a monooxygenase-detoxification pathway. It is postulated that OA diol-ester, as a lipid-soluble, uncharged molecule with a propensity to hydrolyse to OA, may facilitate the transfer of OA across cell walls and membranes.

Animals↗

PubMedDate not supplied

Paralytic shellfish poison reference materials: an intercomparison of methods for the determination of saxitoxin.

Within the framework of the European Commission's Measurements and Testing Programme (BCR) a project has been undertaken to develop shellfish reference materials for Paralytic Shellfish Poisons (PSP). In a preliminary phase of the project, an intercomparison study of methods was undertaken. In this exercise 18 laboratories were asked to analyse solutions of saxitoxin and PSP-containing shellfish extracts with a method of their choice. The study revealed that: all the methods considered (four HPLC methods, one ELISA method) were in principle adequate for the quantification of saxitoxin in solution in the absence of interfering substances (Coefficient of variation (CV) 33% at a concentration of 0.5 microgram/ml); three of the HPLC methods used were able to quantify saxitoxin in PSP-positive mussel extract, the fourth method gave significant overestimation; the CV of all HPLC results was 53% at a mean saxitoxin mass fraction of 2.06 mg/kg mussel meat, the recoveries varied from 59-173%; and the ELISA method grossly overestimated the saxitoxin content in mussel extract, probably due to cross reactions of the antibodies with other PSP. The feasibility of preparing a homogeneous batch of ampouled mussel extracts (CV 3.5% at a saxitoxin concentration of approximately 1.5 mg/kg shellfish), sufficiently stable for at least 4 months storage both at 4 degrees C and approximately 20 degrees C, was demonstrated. The performance of the different methods for the analysis of PSP other than saxitoxin has not yet been evaluated, due to the current lack of PSP standards. Some of the problems observed in the intercomparison study were partly due to the nature of the chromatographic columns used, the composition of the HPLC mobile phase (pH, ion strength), non-optimal conditions for derivatization and matrix interference. Following the outcome of this study, a three year multistage project involving 15-20 European laboratories has been initiated, aimed at improving the accuracy and comparability of PSP measurements as well as preparing reference materials for PSP.

Animals↗

PubMedDate not supplied

The effect of commercial processing on the paralytic shellfish poison (PSP) content of naturally-contaminated Acanthocardia tuberculatum L.

A study was undertaken to determine if any reduction in contamination of Acanthocardia tuberculatum L. (Mediterranean cockle) by paralytic shellfish poisons (PSP) could be enhanced by operations carried out during the industrial canning process, allowing contaminated raw material to be commercially marketed in safe conditions for edible purposes. A general decrease in PSP levels was consistently observed when comparing raw materials and their corresponding final products, these dropping to acceptable levels. PSP levels were determined by mouse bioassay and a fluorometric method, and saxitoxin was determined by HPLC. The detoxifying effects averaged over 71.7% and 81.8% (mouse bioassay), 70.6% and 90.9% (fluorometric method), 77.9% and 83.5% (HPLC), for boiling and sterilizing operations respectively. The highest level detected in raw material was 800 micrograms/100 g by mouse bioassay.

Animals↗

PubMed1989

Serological cross-reactions between crab saxitoxin-induced protein and paralytic shellfish poison-contaminated shellfish.

A polyclonal antiserum generated against crab saxitoxin-induced protein was tested against paralytic shellfish poison (PSP)-contaminated crabs and shellfish. Antibody-reactive proteins in PSP-contaminated bivalve mollusc extracts were localized using SDS-PAGE and immunoblotting. PSP-contaminated clams and oysters possessed a higher degree of immunoreactivity to the saxitoxin-induced protein found in PSP-resistant crabs than their respective non-contaminated controls.

Animals↗

PubMed2000

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis.

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four post-column derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49 mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34 mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX-5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.

Animals↗

PubMed1992

Presence of paralytic shellfish poisoning toxins and soluble proteins in toxic butter clams (Saxidomus giganteus).

Butter clams obtained from a variety of locations along the northern British Columbia coast were assayed for the presence of individual paralytic shellfish poisoning toxins (PSPT) by HPLC and total PSPT toxicity using the mouse bioassay. Specific organs, namely the siphon, adductor muscle, foot and mantle were examined for soluble antigens that crossreacted with crab Saxitoxin-Induced Protein (SIP) using immunochemical (Western blotting) techniques. Butter clams containing high concentrations of PSPT also had several proteins that crossreacted with crab anti-SIP serum. In particular, soluble proteins with distinctly different molecular weights were found in the siphon and foot, respectively, in toxic shellfish. These proteins were absent in nontoxic butter clams. The concept of using PSPT-induced proteins in the butter clam as a screen for identifying toxic shellfish is introduced.

Animals↗

PubMed2001

Quantitative determination of marine toxins associated with diarrhetic shellfish poisoning by liquid chromatography coupled with mass spectrometry.

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 (pa1DTX1), 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.

Chromatography, Liquid↗