yessotoxin and azaspiracid

Microalgae, particularly those from the lineage Dinoflagellata, are very well-known for their ability to produce phycotoxins that may accumulate in the marine food chain and eventually cause poisoning in humans. This includes toxins accumulating in shellfish, such as saxitoxin, okadaic acid, yessotoxins, azaspiracids, brevetoxins, and pinnatoxins. Other toxins, such as ciguatoxins and maitotoxins, accumulate in fish, where, as is the case for the latter compounds, they can be metabolized to even more toxic metabolites. On the other hand, much less is known about the chemical nature of compounds that are toxic to fish, the so-called ichthyotoxins. Despite numerous reports of algal blooms causing massive fish kills worldwide, only a few types of compounds, such as the karlotoxins, have been proven to be true ichthyotoxins. This review will highlight marine microalgae as the source of some of the most complex natural compounds known to mankind, with chemical structures that show no resemblance to what has been characterized from plants, fungi, or bacteria. In addition, it will summarize algal species known to be related to fish-killing blooms, but from which ichthyotoxins are yet to be characterized.

Topics: Animals; Ciguatoxins; Dinoflagellida; Food Contamination; Humans; Marine Toxins; Molecular Structure; Mollusk Venoms; Oxocins; Spiro Compounds

Dinoflagellates are not only important marine primary producers and grazers, but also the major causative agents of harmful algal blooms. It has been reported that many dinoflagellate species can produce various natural toxins. These toxins can be extremely toxic and many of them are effective at far lower dosages than conventional chemical agents. Consumption of seafood contaminated by algal toxins results in various seafood poisoning syndromes: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), diarrheic shellfish poisoning (DSP), ciguatera fish poisoning (CFP) and azaspiracid shellfish poisoning (ASP). Most of these poisonings are caused by neurotoxins which present themselves with highly specific effects on the nervous system of animals, including humans, by interfering with nerve impulse transmission. Neurotoxins are a varied group of compounds, both chemically and pharmacologically. They vary in both chemical structure and mechanism of action, and produce very distinct biological effects, which provides a potential application of these toxins in pharmacology and toxicology. This review summarizes the origin, structure and clinical symptoms of PSP, NSP, CFP, AZP, yessotoxin and palytoxin produced by marine dinoflagellates, as well as their molecular mechanisms of action on voltage-gated ion channels.

Topics: Acrylamides; Animals; Ciguatera Poisoning; Cnidarian Venoms; Dinoflagellida; Humans; Ion Channel Gating; Ion Channels; Marine Toxins; Mollusk Venoms; Neurotoxicity Syndromes; Neurotoxins; Oxocins; Paralysis; Shellfish Poisoning; Spiro Compounds

Low extraction efficiency (60-81%) of okadaic acid (OA) and dinophysistoxin 1 (DTX1) was obtained for 4 out of 5 shellfish species from Washington State (WA), USA, during application of a standard extraction method for determination of lipophilic marine biotoxins by LC-MS/MS as recommended by the European Union Reference Laboratory for Marine Biotoxins (EURLMB). OA and total OA including esters, DTX1, DTX2, and total DTX including esters, azaspiracid 1, 2, and 3 (AZA1, AZA2, and AZA3), pectenotoxin 2 (PTX2), and yessotoxin (YTX) were the toxins examined. Matrix-matched standards prepared from the same control samples used for spike-and-recovery tests were employed to evaluate toxin extraction efficiency and sample clean-up procedures. We adjusted the EURLMB extraction method by either using an acidified methanol extraction or pre-cooking shellfish homogenates at 70 °C for 20 min before EURLMB extraction. Extraction efficiency was improved markedly for OA and DTX1 with both modified methods and for YTX with the pre-cooking step included. However, recoveries were lower for YTX using the acidified methanol extraction and for PTX2 in non-mussel samples with the pre-cooking step. A hexane wash was applied to clean water-diluted non-hydrolyzed samples and a hexane wash was combined with solid-phase extraction for cleaning hydrolyzed samples. Improved sample clean-up, combined with LC-MS/MS adjustments, enabled quantification of U.S. Food and Drug Administration-regulated toxins in five shellfish species from WA with acceptable accuracy using non-matrix matched calibration standards.

Topics: Alkalies; Animals; Chromatography, Liquid; Furans; Lipids; Macrolides; Marine Toxins; Methanol; Mollusk Venoms; Okadaic Acid; Oxocins; Shellfish; Spiro Compounds; Tandem Mass Spectrometry; Washington

A freeze-dried mussel tissue-certified reference material (CRM-FDMT1) was prepared containing the marine algal toxin classes azaspiracids, okadaic acid and dinophysistoxins, yessotoxins, pectenotoxins, cyclic imines, and domoic acid. Thus far, only a limited number of analogues in CRM-FDMT1 have been assigned certified values; however, the complete toxin profile is significantly more complex. Liquid chromatography-high-resolution mass spectrometry was used to profile CRM-FDMT1. Full-scan data was searched against a list of previously reported toxin analogues, and characteristic product ions extracted from all-ion-fragmentation data were used to guide the extent of toxin profiling. A series of targeted and untargeted acquisition MS/MS experiments were then used to collect spectra for analogues. A number of toxins previously reported in the literature but not readily available as standards were tentatively identified including dihydroxy and carboxyhydroxyyessotoxin, azaspiracids-33 and -39, sulfonated pectenotoxin analogues, spirolide variants, and fatty acid acyl esters of okadaic acid and pectenotoxins. Previously unreported toxins were also observed including compounds from the pectenotoxin, azaspiracid, yessotoxin, and spirolide classes. More than one hundred toxin analogues present in CRM-FDMT1 are summarized along with a demonstration of the major acyl ester conjugates of several toxins. Retention index values were assigned for all confirmed or tentatively identified analogues to help with qualitative identification of the broad range of lipophilic toxins present in the material.

Topics: Animals; Bivalvia; Chromatography, High Pressure Liquid; Freeze Drying; Kainic Acid; Marine Toxins; Mollusk Venoms; Okadaic Acid; Oxocins; Reference Standards; Spiro Compounds; Tandem Mass Spectrometry

The first survey of the phycotoxin profile in mussels (Mytilus galloprovincialis) from the coastal waters of Bosnia and Herzegovina (The Bay of Neum, Middle Adriatic Sea) in correlation to the Makarska City Bay (Croatia, Middle Adriatic Sea) was conducted in 2017. Throughout the monitoring period, occasions of gymnodimine (GYM) and azaspiracid (AZA2) shellfish toxicity were recorded in concentrations that do not endanger human health. The occurrence of yessotoxins (YTXs), the most common toxins found in the Adriatic Sea, was correlated to the presence of the Gonyaulax species, a potential source of YTX. The DSP group of toxins is represented by the ester-OA. Phytoplankton analysis confirmed the presence of dinoflagellates from the Prorocentrum genus, a species associated with DSP toxicity. Occurrence frequency and variability of toxin composition were investigated in conjunction to physico-chemical parameters in the surrounding sea water. In the central Adriatic Sea, the infestation period ranges in general from June to August. However, the depuration phase extended beyond September in the Bay of Neum, increasing the length of the decontamination period.

Topics: Animals; Croatia; Dinoflagellida; Heterocyclic Compounds, 3-Ring; Humans; Hydrocarbons, Cyclic; Imines; Marine Toxins; Mollusk Venoms; Mytilus; Oxocins; Phytoplankton; Seafood; Shellfish; Shellfish Poisoning; Spiro Compounds

Lipophilic marine toxins in shellfish pose significant threats to the health of seafood consumers. To assess the contamination status of shellfish by lipophilic marine toxins in the Bohai Sea, nine species of shellfish periodically collected from five representative aquaculture zones throughout a year were analyzed with a method of liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lipophilic marine toxins, including okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), yessotoxin (YTX), homo-yessotoxin (homo-YTX), azaspiracids (AZA2 and AZA3), gymnodimine (GYM), and 13-desmethyl spirolide C (13-DesMe-C), were detected in more than 95 percent of the shellfish samples. Toxins PTX2, YTX, 13-DesMe-C and GYM were predominant components detected in shellfish samples. Scallops, clams and mussels accumulated much higher level of lipophilic marine toxins compared to oysters. Toxin content in shellfish samples collected from different sampling locations showed site-specific seasonal variation patterns. High level of toxins was found during the stages from December to February and June to July in Hangu, while from March to April and August to September in Laishan. Some toxic algae, including Dinophysis acuminata, D. fortii, Prorocentrum lima, Gonyaulax spinifera and Lingulodinium polyedrum, were identified as potential origins of lipophilic marine toxins in the Bohai Sea. The results will offer a sound basis for monitoring marine toxins and protecting the health of seafood consumers.

Topics: Animals; Bivalvia; China; Chromatography, Liquid; Dinoflagellida; Furans; Heterocyclic Compounds, 3-Ring; Hydrocarbons, Cyclic; Imines; Macrolides; Marine Toxins; Mollusk Venoms; Okadaic Acid; Ostreidae; Oxocins; Pyrans; Seafood; Shellfish; Spiro Compounds; Tandem Mass Spectrometry; Water Pollutants, Chemical

Cefas has been responsible for the delivery of official control biotoxin testing of bivalve molluscs from Great Britain for just over a decade. Liquid chromatography tandem mass spectrometric (LC-MS/MS) methodology has been used for the quantitation of lipophilic toxins (LTs) since 2011. The temporal and spatial distribution of okadaic acid group toxins and profiles in bivalves between 2011 and 2016 have been recently reported. Here we present data on the two other groups of regulated lipophilic toxins, azaspiracids (AZAs) and yessotoxins (YTXs), over the same period. The latter group has also been investigated for a potential link with Protoceratium reticulatum and Lingulodinium polyedra, both previously recognised as YTXs producing phytoplankton. On average, AZAs were quantified in 3.2% of all tested samples but notable inter-annual variation in abundance was observed. The majority of all AZA contaminated samples were found between July 2011 and August 2013 in Scotland, while only two, three-month long, AZA events were observed in 2015 and 2016 in the south-west of England. Maximum concentrations were generally reached in late summer or early autumn. Reasons for AZAs persistence during the 2011/2012 and 2012/2013 winters are discussed. Only one toxin profile was identified, represented by both AZA1 and AZA2 toxins at an approximate ratio of 2 : 1, suggesting a single microalgal species was the source of AZAs in British bivalves. Although AZA1 was always the most dominant toxin, its proportion varied between mussels, Pacific oysters and surf clams. The YTXs were the least represented group among regulated LTs. YTXs were found almost exclusively on the south-west coast of Scotland, with the exception of 2013, when the majority of contaminated samples originated from the Shetland Islands. The highest levels were recorded in the summer months and followed a spike in Protoceratium reticulatum cell densities. YTX was the most dominant toxin in shellfish, further strengthening the link to P. reticulatum as the YTX source. Neither homo-YTX, nor 45-OH homo-YTX were detected throughout the monitored period. 45-OH YTX, thought to be a shellfish metabolite associated with YTX elimination, contributed on average 26% in mussels. Although the correlation between 45-OH YTX abundance and the speed of YTX depuration could not be confirmed, we noted the half-life of YTX was more than two-times longer in queen scallops, which contained 100% YTX, than in mussels. No other b

Topics: Animals; Bivalvia; Chromatography, Liquid; England; Marine Toxins; Mollusk Venoms; Oxocins; Scotland; Spiro Compounds; Tandem Mass Spectrometry; United Kingdom

Some dinoflagellates can produce lipophilic marine toxins, which pose potent threats to seafood consumers. In the Bohai Sea, an important semi-closed inland sea with intensive mariculture industry in China, there is little knowledge concerning lipophilic marine toxins and their potential threats. In this study, net-concentrated phytoplankton samples were periodically collected from 5 typical mariculture zones around the Bohai Sea, including Laishan (LS), Laizhou (LZ), Hangu (HG), Qinhuangdao (QHD) and Huludao (HLD) in 2013 and 2014, and a method using high performance liquid chromatography (HPLC) coupled with a Q-Trap mass spectrometer was applied to analyze seven representative lipophilic marine toxins, including okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), yessotoxin (YTX), azaspiracid-1 (AZA1), gymnodimine (GYM), and 13-desmethyl spirolide C (desMeC). The method had high sensitivity and repeatability, and exhibited satisfactory recoveries for most of the lipophilic marine toxins (92.1-108%) except for AZA1 (65.8-68.9%). Nearly all the lipophilic marine toxins could be detected in phytoplankton samples from the Bohai Sea. OA, DTX1 and PTX2 were predominant components and present in most of the phytoplankton samples. The maximum content of lipophilic marine toxin in phytoplankton samples concentrated from seawater (OA 464 pg L

Topics: Animals; China; Chromatography, High Pressure Liquid; Dinoflagellida; Furans; Heterocyclic Compounds, 3-Ring; Hydrocarbons, Cyclic; Hydrophobic and Hydrophilic Interactions; Imines; Macrolides; Marine Toxins; Mollusk Venoms; Okadaic Acid; Oxocins; Phytoplankton; Pyrans; Seafood; Spiro Compounds; Tandem Mass Spectrometry

Accurate quantitative analysis of lipophilic toxins by liquid chromatography/mass spectrometry (LC/MS) requires calibration solution reference materials (RMs) for individual toxin analogs. Untargeted analysis is aimed at identifying a vast number of compounds and thus validation of fully quantitative untargeted methods is not feasible. However, a semi-quantitative approach allowing for profiling is still required and will be strengthened by knowledge of the relative molar response (RMR) of analogs in LC/MS with electrospray ionization (ESI).. RMR factors were evaluated for toxins from the okadaic acid (OA/DTXs), yessotoxin (YTX), pectenotoxin (PTX), azaspiracid (AZA) and cyclic imine (CI) toxin groups, in both solvent standards and environmental sample extracts. Since compound ionization and fragmentation influences the MS response of toxins, RMRs were assessed under different chromatographic conditions (gradient, isocratic) and MS acquisition modes (SIM, SRM, All-ion, target MS/MS) on low- and high-resolution mass spectrometers.. In general, RMRs were not significantly impacted by chromatographic conditions (isocratic vs gradient), with the exception of DTX1. MS acquisition modes had a more significant impact, with PnTX-G and SPX differing notably. For a given toxin group, response factors were generally in the range of 0.5 to 2. The cyclic imines were an exception.. Differences in RMRs between toxins of a same chemical base structure were not significant enough to indicate major issues for non-targeted semi-quantitative analysis, where there is limited or no availability of standards for many compounds, and where high degrees of accuracy are not required. Differences in RMRs should be considered when developing methods that use a standard of a single analogue to quantitate other toxins from the same group.

Topics: Chromatography, Liquid; Harmful Algal Bloom; Marine Toxins; Mollusk Venoms; Okadaic Acid; Oxocins; Reference Standards; Spectrometry, Mass, Electrospray Ionization; Spiro Compounds

Yessotoxins (YTX) and azaspiracids (AZAs) are marine toxins produced by phytoplanktonic dinoflagellates that get accumulated in filter feeding shellfish and finally reach human consumers through the food web. Both toxin classes are worldwide distributed, and food safety authorities have regulated their content in shellfish in many countries. Recently, YTXs and AZAs have been described as compounds with subacute cardiotoxic potential in rats owed to alterations of the cardiovascular function and ultrastructural heart damage. These molecules are also well known in vitro inducers of cell death. The aim of this study was to explore the presence of cardiomyocyte death after repeated subacute exposure of rats to AZA-1 and YTX for 15 days. Because autophagy and apoptosis are often found in dying cardiomyocytes, several autophagic and apoptotic markers were determined by western blot in heart tissues of these rats. The results showed that hearts from YTX-treated rats presented increased levels of the autophagic markers microtubule-associated protein light chain 3-II (LC3-II) and beclin-1, nevertheless AZA-1-treated hearts evidenced increased levels of the apoptosis markers cleaved caspase-3 and -8, cleaved PARP and Fas ligand. Therefore, while YTX-induced damage to the heart triggers autophagic processes, apoptosis activation occurs in the case of AZA-1. For the first time, activation of cell death signals in cardiomyocytes is demonstrated for these toxins with in vivo experiments, which may be related to alterations of the cardiovascular function.

Topics: Animals; Apoptosis; Autophagy; Biomarkers; Blotting, Western; Female; Marine Toxins; Mollusk Venoms; Myocytes, Cardiac; Oxocins; Rats; Rats, Sprague-Dawley; Spiro Compounds; Time Factors; Toxicity Tests, Subacute

A freeze-dried mussel tissue (Mytilus edulis) reference material (CRM-FDMT1) was produced containing multiple groups of shellfish toxins. Homogeneity and stability testing showed the material to be fit for purpose. The next phase of work was to assign certified values and uncertainties to 10 analytes from six different toxin groups. Efforts involved optimizing extraction procedures for the various toxin groups and performing measurements using liquid chromatography-based analytical methods. A key aspect of the work was compensating for matrix effects associated with liquid chromatography-mass spectrometry through standard addition, dilution, or matrix-matched calibration. Certified mass fraction values are reported as mg/kg of CRM-FDMT1 powder as bottled for azaspiracid-1, -2, and -3 (4.10 ± 0.40; 1.13± 0.10; 0.96 ± 0.10, respectively), okadaic acid, dinophysistoxin-1 and -2 (1.59 ± 0.18; 0.68 ± 0.07; 3.57± 0.33, respectively), yessotoxin (2.49 ± 0.28), pectenotoxin-2 (0.66 ± 0.06), 13-desmethylspirolide-C (2.70 ± 0.26), and domoic acid (126 ± 10). Combined uncertainties for the certified values include contributions from homogeneity, stability, and characterization experiments. The commutability of CRM-FDMT1 was assessed by examining the extractability and matrix effects for the freeze-dried material in comparison with its equivalent wet tissue homogenate. CRM-FDMT1 is the first shellfish matrix CRM with certified values for yessotoxins, pectenotoxins or spirolides, and is the first CRM certified for multiple toxin groups. CRM-FDMT1 is a valuable tool for quality assurance of phycotoxin monitoring programs and for analytical method development and validation. Graphical Abstract CRM-FDMT1 is a multi-toxin mussel tissue certified reference material (CRM) to aid in development and validation of analytical methods for measuring the levels of algal toxins in seafood.

Topics: Animals; Chromatography, Liquid; Freeze Drying; Furans; Kainic Acid; Macrolides; Marine Toxins; Mass Spectrometry; Mollusk Venoms; Mytilus edulis; Okadaic Acid; Oxocins; Pyrans; Reference Standards; Seafood; Spiro Compounds

Phycotoxins are monitored in seafood because they can cause food poisonings in humans. Phycotoxins do not only occur singly but also as mixtures in shellfish. The aim of this study was to evaluate the in vitro toxic interactions of binary combinations of three lipophilic phycotoxins commonly found in Europe (okadaic acid (OA), yessotoxin (YTX) and azaspiracid-1 (AZA-1)) using the neutral red uptake assay on two human intestinal cell models, Caco-2 and the human intestinal epithelial crypt-like cells (HIEC). Based on the cytotoxicity of individual toxins, we studied the interactions between toxins in binary mixtures using the combination index-isobologram equation, a method widely used in pharmacology to study drug interactions. This method quantitatively classifies interactions between toxins in mixtures as synergistic, additive or antagonistic. AZA-1/OA, and YTX/OA mixtures showed increasing antagonism with increasing toxin concentrations. In contrast, the AZA-1/YTX mixture showed increasing synergism with increasing concentrations, especially for mixtures with high YTX concentrations. These results highlight the hazard potency of AZA-1/YTX mixtures with regard to seafood intoxication.

Topics: Caco-2 Cells; Cell Line; Cell Survival; Drug Interactions; Food Contamination; Humans; Marine Toxins; Mollusk Venoms; Neutral Red; Okadaic Acid; Oxocins; Seafood; Spiro Compounds

Azaspiracids (AZAs) are lipophilic biotoxins produced by marine algae that can contaminate shellfish and cause human illness. The European Union (EU) regulates the level of AZAs in shellfish destined for the commercial market, with liquid chromatography-mass spectrometry (LC-MS) being used as the official reference method for regulatory analysis. Certified reference materials (CRMs) are essential tools for the development, validation, and quality control of LC-MS methods. This paper describes the work that went into the planning, preparation, characterization, and certification of CRM-AZA-Mus, a tissue matrix CRM, which was prepared as a wet homogenate from mussels (Mytilus edulis) naturally contaminated with AZAs. The homogeneity and stability of CRM-AZA-Mus were evaluated, and the CRM was found to be fit for purpose. Extraction and LC-MS/MS methods were developed to accurately certify the concentrations of AZA1 (1.16 mg/kg), AZA2 (0.27 mg/kg), and AZA3 (0.21 mg/kg) in the CRM. Quantitation methods based on standard addition and matrix-matched calibration were used to compensate for the matrix effects in LC-MS/MS. Other toxins present in this CRM at lower levels were also measured with information values reported for okadaic acid, dinophysistoxin-2, yessotoxin, and several spirolides.

Topics: Animals; Calibration; Chromatography, Liquid; Marine Toxins; Mollusk Venoms; Mytilus edulis; Okadaic Acid; Oxocins; Pyrans; Reference Standards; Spiro Compounds; Tandem Mass Spectrometry

A new method for the analysis of lipophilic marine biotoxins (okadaic acid, dinophysistoxins, azaspiracids, pectenotoxins, yessotoxins, spirolids) in fresh and canned bivalves has been developed. A QuEChERS methodology is applied; i.e. the analytes are extracted with acetonitrile and clean-up of the extracts is performed by dispersive solid phase extraction with C18. The extracts are analyzed by ultra-high performance liquid chromatography coupled to a hybrid quadrupole-Orbitrap mass spectrometer, operating in tandem mass spectrometry mode, with resolution set at 70,000 (m/z 200, FWHM). Separation of the analytes, which takes about 10min, is carried out in gradient elution mode with a BEH C18 column and mobile phases based on 6.7mM ammonia aqueous solution and acetonitrile mixtures. For each analyte the molecular ion and 1 or 2 product ions are acquired, with a mass accuracy better than 5ppm. The quantification is performed using surrogate matrix matched standards, with eprinomectin as internal standard. The high-throughput method, which has been successfully validated, fulfills the requirements of European Union legislation, and has been implemented as a routine method in a public health laboratory.

Topics: Acetonitriles; Ammonia; Animals; Bivalvia; Chromatography, High Pressure Liquid; Food Analysis; Marine Toxins; Mollusk Venoms; Okadaic Acid; Oxocins; Solid Phase Extraction; Spiro Compounds; Tandem Mass Spectrometry

The presence of phytoplankton responsible for the production of lipophilic marine biotoxins is well recognised throughout parts of South America. To date, the quantitation of lipophilic toxins in Argentinean shellfish has been limited to select and highly focussed geographical studies. This work reports the analysis for lipophilic marine biotoxins in shellfish harvested across five regions of Argentina between 1992 and 2012. LC-MS/MS analysis was used for the quantitation of all regulated lipophilic toxins. High concentrations of okadaic acid group toxins were quantified, with a clear dominance of the parent okadaic acid and more than 90% of the toxin present as esters. Results showed DSP toxins in shellfish from the Buenos Aires Province during 2006 and 2007, earlier than previously described. There was also strong evidence linking the presence of okadaic acid to human intoxications. Other lipophilic toxins detected were yessotoxin, pectenotoxin-2 and 13-desMeC spirolide. With evidence published recently for the presence of azaspiracid producers, this work reports the detection of low concentrations of azaspiracid-2 in shellfish. As such the data provides the first published evidence for yessotoxins and azaspiracids in Argentinean shellfish and further evidence for the continuing presence of lipophilic marine toxins in Argentinean waters.

Topics: Animals; Argentina; Chromatography, Liquid; Food Contamination; Furans; Humans; Macrolides; Marine Toxins; Mollusk Venoms; Okadaic Acid; Oxocins; Phytoplankton; Pyrans; Shellfish; Shellfish Poisoning; Spiro Compounds; Tandem Mass Spectrometry

Different clinical types of algae-related poisoning have attracted scientific and commercial attention: paralytic shellfish poisoning (PSP), diarrhetic shellfish poisoning (DSP), and amnesic shellfish poisoning (ASP). Bioassays are common methods for the determination of marine biotoxins. However, biological tests are not completely satisfactory, mainly due to the low sensitivity and the absence of specialized variations. In this context LC-MS methods replaced HPLC methods with optical detectors, allowing both effective seafood control and monitoring of phytoplankton in terms of the different groups of marine biotoxins. This chapter describes state-of-the-art LC-MS/MS methods for the detection and quantitation of different classes of phycotoxins in shellfish matrices. These classes include the highly hydrophilic paralytic shellfish poisoning (PSP) toxins. Hydrophilic interaction liquid chromatography (HILIC) has been shown to be useful in the separation of PSP toxins and is described in detail within this chapter. Another important class of phycotoxins is diarrhetic shellfish poisoning (DSP) toxins. This group traditionally comprises okadaic acid and dinophysistoxins (DTXs), pectenotoxins (PTXs), and yessotoxins (YTXs). The most recently described shellfish poisoning syndrome, azaspiracid shellfish poisoning (AZP) is caused by azaspiracids, which in turn are diarrhetic, but usually are treated separately as AZP. The last group of regulated shellfish toxins is the amnesic shellfish poisoning (ASP) toxin domoic acid, produced by species of the genus Pseudo-nitzschia.

Topics: Chromatography, Liquid; Kainic Acid; Macrolides; Marine Toxins; Mollusk Venoms; Okadaic Acid; Oxocins; Pyrans; Shellfish; Spiro Compounds; Tandem Mass Spectrometry

This study describes the development of Response Surface Pathway (RSP) design, assesses its performance and effectiveness in estimating LD50, and compares RSP with Up and Down Procedures (UDPs) and Random Walk (RW) design.. A basic 4-level RSP design was used on 36 male ICR mice given intraperitoneal doses of Yessotoxin. Simulations were performed to optimise the design. A k-adjustment factor was introduced to ensure coverage of the dose window and calculate the dose steps. Instead of using equal numbers of mice on all levels, the number of mice was increased at each design level. Additionally, the binomial outcome variable was changed to multinomial. The performance of the RSP designs and a comparison of UDPs and RW were assessed by simulations. The optimised 4-level RSP design was used on 24 female NMRI mice given Azaspiracid-1 intraperitoneally.. The in vivo experiment with basic 4-level RSP design estimated the LD50 of Yessotoxin to be 463 μg/kgBW (95% CI: 383-535). By inclusion of the k-adjustment factor with equal or increasing numbers of mice on increasing dose levels, the estimate changed to 481 μg/kgBW (95% CI: 362-566) and 447 μg/kgBW (95% CI: 378-504 μg/kgBW), respectively. The optimised 4-level RSP estimated the LD50 to be 473 μg/kgBW (95% CI: 442-517). A similar increase in power was demonstrated using the optimised RSP design on real Azaspiracid-1 data. The simulations showed that the inclusion of the k-adjustment factor, reduction in sample size by increasing the number of mice on higher design levels and incorporation of a multinomial outcome gave estimates of the LD50 that were as good as those with the basic RSP design. Furthermore, optimised RSP design performed on just three levels reduced the number of animals from 36 to 15 without loss of information, when compared with the 4-level designs. Simulated comparison of the RSP design with UDPs and RW design demonstrated the superiority of RSP.. Optimised RSP design reduces the number of animals needed. The design converges rapidly on the area of interest and is at least as efficient as both the UDPs and RW design.

Topics: Animal Use Alternatives; Animals; Computer Simulation; Female; Lethal Dose 50; Male; Marine Toxins; Mice; Mice, Inbred ICR; Models, Biological; Mollusk Venoms; Oxocins; Research Design; Spiro Compounds; Toxicity Tests

A liquid chromatography quadrupole linear ion trap mass spectrometry method with fast polarity switching and a scheduled multiple reaction monitoring algorithm mode was developed for multiclass screening and identification of lipophilic marine biotoxins in bivalve molluscs. A major advantage of the method is that it can detect members of all six groups of lipophilic marine biotoxins [okadaic acid (OA), yessotoxins (YTX), azaspiracids (AZA), pectenotoxins (PTX), cyclic imines (CI), and brevetoxins (PbTx)], thereby allowing quantification and high confidence identification from a single liquid chromatography tandem mass spectrometry (LC-MS/MS) injection. An enhanced product ion (EPI) library was constructed after triggered collection of data via information-dependent acquisition (IDA) of EPI spectra from standard samples. A separation method for identifying 17 target toxins in a single analysis within 12min was developed and tested. Different solid phase extraction sorbents, the matrix effect (for oyster, scallop, and mussel samples), and stability of the standards also were evaluated. Matrix-matched calibration was used for quantification of the toxins. The limits of detection were 0.12-13.6μg/kg, and the limits of quantification were 0.39-45.4μg/kg. The method was used to analyze 120 shellfish samples collected from farming areas along the coast of China, and 7% of the samples were found to be contaminated with toxins. The library search identified PbTx-3, YTX, OA, PTX2, AZA1, AZA2, and desmethylspirolide C (SPX1). Overall, the method exhibited excellent sensitivity and reproducibility, and it will have broad applications in the monitoring of lipophilic marine biotoxins.

Topics: Animals; Bivalvia; Chromatography, High Pressure Liquid; Food Analysis; Gas Chromatography-Mass Spectrometry; Humans; Hydrophobic and Hydrophilic Interactions; Imines; Limit of Detection; Macrolides; Marine Toxins; Mollusk Venoms; Okadaic Acid; Ostreidae; Oxocins; Pectinidae; Pyrans; Reference Standards; Reproducibility of Results; Shellfish; Solid Phase Extraction; Spiro Compounds; Tandem Mass Spectrometry

Graphene is a novel carbonic material with great potentials for the use as sorbent due to its ultrahigh surface area. Herein, we report the use of graphene as sorbent in solid-phase extraction (SPE) using pipette tip as cartridge namely GPT-SPE, together with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), for the analysis of lipophilic marine toxins (LMTs), including yessotoxins (YTX), okadaic acid (OA), dinophysistoxin-1 (DTX1), gymnodimine (GYM), spirolides-1 (SPX1), pectenotoxin-2 (PTX2) and azaspiracid-1 (AZA1) in shellfish. The GPT-SPE procedure was optimized and the performance of graphene was fully validated. Results with high-sensitivity and good reproducibility was obtained and compared with that of other sorbents like C18 silica, multi-walled carbon nanotubes (MWCNTs), commercial Oasis HLB, and Strata-X for the extraction of LMTs, which showed superiority and advantages of graphene, such as good recoveries, stability and compatibility with various solvents. In order to exhibit the potentials of graphene as an excellent sorbent material, 67 mussel samples from six coastal cities of China were analyzed. OA was found to be the dominant contaminant, while YTX was also detected with low level.

Topics: Adsorption; Animals; Bivalvia; Chromatography, High Pressure Liquid; Furans; Graphite; Heterocyclic Compounds, 3-Ring; Hydrocarbons, Cyclic; Imines; Macrolides; Marine Toxins; Mollusk Venoms; Muscles; Okadaic Acid; Oxocins; Pyrans; Reproducibility of Results; Sensitivity and Specificity; Shellfish; Solid Phase Extraction; Spiro Compounds; Tandem Mass Spectrometry

Although there has been much progress with regard to marine toxins from dinoflagellates, much remains to be done. Because these compounds are a seafood consumer risk, the demands cover from legislative to scientific aspects. Legislation is required for all new toxins that appear in the coasts. On the other hand, it is important to understand the toxicity of the different analogues, in terms of both the relative toxicity to reference compounds and the mechanism of toxicity itself, both acute and long-term. For this, a uniform approach to do toxic studies is necessary, especially acute toxicity. The need for pure standards in sufficient supply and the understanding of the mode of action of some of the compounds (such as yessotoxin or azaspiracids) will help the development of another important field, the use of marine toxins as drug leads, and the chemistry around them.

Topics: Administration, Oral; Animals; Food Safety; Marine Toxins; Mice; Mollusk Venoms; Oxocins; Risk Assessment; Spiro Compounds; Stomach

For many years, the presence of yessotoxins (YTXs) in shellfish has contributed to the outcome of the traditional mouse bioassay and has on many occasions caused closure of shellfisheries. Since YTXs do not appear to cause diarrhoea in man and exert low oral toxicity in animal experiments, it has been suggested that they should be removed from regulation. Before doing so, it is important to determine whether the oral toxicity of YTXs is enhanced when present together with shellfish toxins known to cause damage to the gastrointestinal tract. Consequently, mice were given high doses of YTX, at 1 or 5 mg/kg body weight, either alone or together with azaspiracid-1 (AZA1) at 200 μg/kg. The latter has been shown to induce damage to the small intestine at this level. The combined exposure caused no clinical effects, and no pathological changes were observed in internal organs. These results correspond well with the very low levels of YTX detected in internal organs by means of LC-MS/MS and ELISA after dosing. Indeed, the very low absorption of YTX when given alone remained largely unchanged when YTX was administered in combination with AZA1. Thus, the oral toxicity of YTX is not enhanced in the presence of sub-lethal levels of AZA1.

Topics: Administration, Oral; Animals; Chromatography, Liquid; Drug Combinations; Enzyme-Linked Immunosorbent Assay; Female; Marine Toxins; Mice; Mice, Mutant Strains; Mollusk Venoms; Oxocins; Spiro Compounds; Tandem Mass Spectrometry

Chinese shellfish samples were harvested from different locations along the Chinese coast. These shellfish were analyzed by liquid chromatography in combination with mass spectrometry to detect the following toxins: okadaic acid (OA), dinophysistoxins (DTXs), petenotoxins (PTXs), azaspiracids (AZAs), yessotoxins (YTXs), spirlides (SPXs) and gymnodimines (GYM). The results revealed the lipophilic toxin profiles varied with shellfish sampling locations. In addition to OA, GYM and YTX derivatives, PTX-2 and its derivatives were found for the first time in the following Chinese shellfish: Crassostrea gigas, Mactra chinensis and Mytilus galloprovincialis. The presence of GYM, YTXs, OA and PTXs in Chinese shellfish collected from regions where no previous record of DSP-neutral toxic compounds was reported. Serious efforts should therefore be made to conduct a phycotoxin monitoring program to detect the presence of lipophilic toxins in biological materials of marine origin, which may ensure that Chinese seafood products do not present a health risk. With respect to suspected carcinogenicity, further research on the distribution and concentrations of toxic compounds are needed, in order to carry out long-term risk assessments, particularly sub-acute and chronic toxicity tests associated with of lower doses.

Topics: Chromatography, High Pressure Liquid; Furans; Heterocyclic Compounds, 3-Ring; Hydrocarbons, Cyclic; Imines; Macrolides; Marine Toxins; Mass Spectrometry; Mollusk Venoms; Okadaic Acid; Oxocins; Pyrans; Shellfish; Spiro Compounds

Combining mass spectrometric tools, a total of 47 in vitro metabolites of okadaic acid (OA), dinophysistoxins 1 and 2 (DTX1 and DTX2), yessotoxin (YTX), azaspiracid1 (AZA1), and pectenotoxin 2 (PTX2) could be detected and confirmed after an incubation with rat liver S9-mix. In a first step, liquid chromatography (LC) combined with tandem mass spectrometry (MS/MS) was used as a screening tool for the identification of in vitro metabolites of lipophilic marine biotoxins. Metabolic phase I and phase II reactions were screened for metabolites by calculating and subsequently monitoring theoretical MS transitions. In a second step, metabolites were confirmed by determination of accurate masses using high resolution MS provided by Orbitrap technology. Subsequently, product ion spectra, precursor ion spectra, and MS3 spectra were recorded for structure elucidation of metabolites. While all investigated toxins were found to form various oxygenated metabolites during the oxidative phase I metabolism, those metabolites varied in the number of added oxygen atoms and in the number of individual isomers. No hints were obtained concerning the formation of glutathione adducts, and a conjugation with glucuronic acid was detected for AZA1 only.

Topics: Animals; Furans; Hydrophobic and Hydrophilic Interactions; Liver; Macrolides; Male; Marine Toxins; Metabolic Detoxication, Phase I; Metabolic Detoxication, Phase II; Mollusk Venoms; Oxocins; Pyrans; Rats; Shellfish Poisoning; Spiro Compounds; Tandem Mass Spectrometry

The French Phytoplankton and Phycotoxins monitoring network (REPHY) recently found positive or dubious negative shellfish samples using lipophilic toxins mouse bioassay. These samples were analyzed by liquid chromatography (LC) in combination with mass spectrometry (MS) to detect the following toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs), yessotoxins (YTXs), spirolides (SPXs) and gymnodimines (GYMs). Over the 2006-2007 period, chemical analyses revealed various lipophilic toxin profiles according to shellfish sampling locations. In addition to OA and/or PTX-2 and their derivatives, several other compounds were found for the first time in France: (1) during the summer of 2006, AZA-1 and AZA-2 in Queen scallops (Aequipecten opercularis) from Northern Brittany; (2) during the summer of 2007, YTX and its major metabolites (45-hydroxy-YTX, homo-YTX, carboxy-YTX) in shellfish from the Mediterranean coast. Regarding YTX-group, the toxin profiles evolution in mussels during summer showed that: (i) the carboxy-YTX depuration rate was much slower than the YTX and 45-hydroxy-YTX ones; (ii) the homo-YTX concentration, which was initially very weak, increased significantly during the last depuration phase, which seems to reveal a YTX-group high metabolisation level in mussels. This paper reports for the first time on AZA and YTX-groups detection in French shellfish.

Topics: Animals; Chromatography, Liquid; Environmental Monitoring; Food Contamination; Marine Toxins; Mass Spectrometry; Mollusk Venoms; Oxocins; Shellfish; Spiro Compounds

Azaspiracids cause severe damages in the epithelium of several organs. In this study we have investigated the effects of azaspiracid-1 (AZA-1) on two epithelial cell lines. Nanomolar concentrations of AZA-1 reduced MCF-7 cell proliferation and impaired cell-cell adhesion. AZA-1 altered the cellular pool of the adhesion molecule E-cadherin by inducing a dose- and time-dependent accumulation of an E-cadherin fragment (E-cadherin-related antigen [ECRA(100)]), with a concentration inducing the half-maximal effect (EC(50)) of 0.47nM. The immunological characterization of ECRA(100) revealed that it consists of an E-cadherin molecule lacking the intracellular domain, and these data showed that the effect induced by AZA-1 in MCF-7 cells is undistinguishable from that induced by yessotoxin (YTX) in the same experimental system. A comparison of toxin effects in MCF-7 and Caco 2 cells confirmed that the effects induced by AZA-1 and YTX are undistinguishable in these cells. Treatment of fibroblasts with AZA-1 did not affect the cellular pool of N-cadherin showing that the toxin effect is cadherin-specific. A comparison of the effects induced by AZA-1, YTX, and okadaic acid on F-actin and E-cadherin in MCF-7 and Caco 2 cells showed that 1nM AZA-1 did not cause significant changes in F-actin and that accumulation of ECRA(100) did not correlate with decreased levels of F-actin under our experimental conditions. Matching our results with those available in literature, we notice that, when molecular effects induced by AZA-1 and YTX have been studied in the same in vitro systems, experimental data show that they are undistinguishable in terms of sensitive cellular parameters, effective doses, and kinetics of responses in several cell lines. The possibility that azaspiracids and YTXs might share their molecular mechanism(s) of action in defined biological settings should be considered.

Topics: Actins; Animals; Cadherins; Cell Adhesion; Cell Line, Tumor; Cell Proliferation; Cytoskeleton; Dose-Response Relationship, Drug; Epithelial Cells; Ethers, Cyclic; Fibroblasts; Humans; Marine Toxins; Mice; Mollusk Venoms; Mytilus edulis; Oxocins; Spiro Compounds; Time Factors

The effect of gamma-irradiation on concentrations of hydrophilic and lipophilic phycotoxins has been investigated by use of HPLC-UV and LC-MS. Pure toxins in organic solvents and toxins in mussel (Mytilus edulis) tissues were irradiated at three different doses. In solution all toxin concentrations were reduced to some extent. Most severe decreases were observed for domoic acid and yessotoxin, for which the smallest dose of irradiation led to almost complete destruction. For pectenotoxin-2 the decrease in concentration was less severe but still continuous with increasing dose. Azaspiracid-1 and okadaic acid were the least affected in solution. In shellfish tissue the decrease in toxin concentrations was much reduced compared with the effect in solution. After irradiation at the highest dose reductions in concentrations were between ca. 5 and 20% for the lipophilic toxins and there was no statistical difference between control and irradiated samples for azaspiracids in tissue. Irradiation of shellfish tissues contaminated with domoic acid led to a more continuous decrease in the amount of the toxin with increasing dose. The effect of irradiation on the viability of microbial activity in shellfish tissues was assessed by using total viable counting techniques. Microbial activity depended on the type of shellfish and on the pretreatment of the shellfish tissues (with or without heat treatment). As far as we are aware this is the first investigation of the effectiveness of irradiation as a technique for stabilising tissue reference materials for determination of phycotoxins. Our results suggest that this technique is not effective for materials containing domoic acid. It does, however, merit further investigation as a stabilisation procedure for preparation of shellfish tissue materials for some lipophilic toxins, in particular azaspiracids. Chemical structures of the toxins investigated in the study.

Topics: Animals; Calibration; Chemistry Techniques, Analytical; Chromatography, High Pressure Liquid; Chromatography, Liquid; Ethers, Cyclic; Gamma Rays; Kainic Acid; Macrolides; Marine Toxins; Mass Spectrometry; Mollusk Venoms; Okadaic Acid; Oxocins; Pyrans; Reference Values; Shellfish; Spectrophotometry, Ultraviolet; Spiro Compounds