Occurrence of paralytic shellfish poison (PSP)-producing dinoflagellate Alexandrium tamarense in Hiroshima Bay, Hiroshima Prefecture, Japan, during 1993-2004 and its PSP profiles

To assess levels of shellfish intoxication by the paralytic shellfish poison (PSP)-producing dinoflagellate Alexandrium tamarense, potential health risks to human shellfish consumers and the possible need for regulatory intervention, yearly variations of maximum cell density of this species were examined from 1993 to 2004 in Kure Bay and Kaita Bay, which are located within Hiroshima Bay, Hiroshima Prefecture, Japan. The seawater temperature was determined concomitantly. In Kure Bay, maximum concentrations of 1,400 and 1,300 cells/mL at 0 and 5 m depths were observed on 21 and 24 April 1997. In Kaita Bay, remarkably high concentrations above 1,000 cells/mL of A. tamarense were observed in two out of three years investigated. These facts suggest that the environment in both bays is favorable for the propagation of A. tamarense. The temperature range at which the natural population of A. tamarense blooms was generally from 12 to 16 degrees C. Four strains (ATKR-94, -95, -97 and -01) from Kure Bay and one strain (ATKT-97) from Kaita Bay were established. The strain ATKR-94, cultured in modified SW-2 medium at 15 degrees C for 15 days, showed a specific toxicity of 33.8 x 10(-6) MU/cell. The toxins in all five strains exist almost exclusively as beta-epimers (C2 (PX2 or GTX8), GTX3, dcGTX3 and GTX4), which accounted for 54.9 to 73.0 mol% of the total. The corresponding a-epimers (C1 (PX1 or epi-GTX8), GTX2, dcGTX2 and GTX1) accounted for 6.0 to 28.9 mol%. The toxin profiles of ATKR-97 and ATKT-97 were characterized by unusually high proportions of low-potency sulfocarbamoyl toxin, which comprised 62.4 and 68.2 mol%, respectively, of total toxins. In the toxic bivalves, the low-toxicity sulfocarbamoyl components, major components of A. tamarense, were present in amounts of only a few percent, suggesting that in vivo conversion of PSP occurs after ingestion. A comparison of the toxin profiles of the causative dinoflagellate and contaminated bivalves showed that PSP components exist in the bivalves in the form of alpha-epimers, presumably owing to accumulation or storage of the toxins.     

Matrix effect on paralytic shellfish toxins quantification and toxicity estimation in mussels exposed to Gymnodinium catenatum

Paralytic shellfish toxins were quantified in whole tissues of the mussel Mytilus galloprovincialis exposed to blooms of the dinoflagellate Gymnodinium catenatum in Portuguese coastal waters. A validated liquid chromatography method with fluorescence detection, involving pre-chromatographic oxidation was used to quantify carbamoyl, N-sulfocarbamoyl and decarbamoyl toxins. In order to test for any matrix effect in the quantification of those toxins, concentrations obtained from solvent and matrix matched calibration curves were compared. A suppression of the fluorescence signal was observed in mussel extract or fraction in comparison to solvent for the compounds dcGTX2 + 3, GTX2 + 3 and GTX1 + 4, while an enhancement was found for C1 + 2, dcSTX, STX, B1, dcNEO and NEO. These results showed that a matrix effect varies among compounds. The difference of concentrations between solvent and matrix matched calibration curves for C1 + 2 (median = 421 ng g?1) exceeded largely the values for the other quantified compounds (0.09-58 ng g?1). Those differences were converted into toxicity differences, using Oshima toxicity equivalence factors. The compounds C1 + 2 and dcNEO were the major contributors to the differences of total toxicity in the mussel samples. The differences of total toxicity were calculated in ten mussel samples collected during a 10-week blooming period in Portuguese coastal lagoon. Values varied between 53 and 218 μg STX equivalents kg?1. The positive differences mean that the estimated toxicity using solvent calibration curves exceed the values taking into account the matrix. For the toxicity interval 200-800 μg STX equivalents kg?1 an increase was found between 44 and 28%.     

Accumulation of paralytic shellfish poison (PSP) and biotransformation of its components in oysters, Crassostrea gigas, fed with the toxic dinoflagellate Alexandrium tamarense

As a part of our studies on the mechanism of uptake of paralytic shellfish poison (PSP) and the kinetics of its accumulation in bivalves, oysters Crassostrea gigas were experimentally contaminated with PSP by being fed with the toxic dinoflagellate Alexandrium tamarense for 2, 4, 6, 8 and 10 days. Temporal variations in the PSP contents and their profiles in oysters during the feeding experiment were monitored by high-performance liquid chromatography (HPLC) and the toxin profile of the oysters was compared with that of A. tamarense. Toxins excreted from the infested oysters into the seawater for 2 and 10 days were recovered and analyzed by HPLC. PSP toxicity rapidly appeared in the tissues of oysters and their toxicity levels reached 0.6 (0.3), 2.2 (1.1), 1.0 (0.5), 3.4 (1.6) and 1.1 (0.5) MU/g (nmol/g) shucked meat at 2, 4, 6, 8 and 10 days, respectively. The accumulation rates of toxin, calculated from the total amount (nmol) of toxins expressed by the total cell number fed during the exposure period and the toxicity of the oysters, were 14.1, 18.7, 5.1, 14.9 and 3.2% for 2, 4, 6, 8 and 10 days. During feeding experiments, the toxin profile of oysters changed substantially, showing marked differences from the proportions found in the toxigenic dinoflagellate used as food. The toxin components in this strain existed almost exclusively as beta-epimers, which accounted for 66.3 mol% of the total. This contrasts with the case of the oysters, where the beta-epimers represented 24.8, 29.8, 25.1, 27.3 and 25.2 mol% of the total at 2, 4, 6, 8 and 10 days, respectively. The amount of gonyautoxin-1 (GTX1) accumulated in oysters increased linearly and slowly for 8 days and the maximum content of GTX1 reached 51.3 mol%. The composition of GTX group compounds recovered from the seawater in which the oysters had been reared was a little different from that within the oyster tissues.     

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.     

Matrix effect on paralytic shellfish toxins quantification and toxicity estimation in mussels exposed to Gymnodinium catenatum

Paralytic shellfish toxins were quantified in whole tissues of the mussel Mytilus galloprovincialis exposed to blooms of the dinoflagellate Gymnodinium catenatum in Portuguese coastal waters. A validated liquid chromatography method with fluorescence detection, involving pre-chromatographic oxidation was used to quantify carbamoyl, N-sulfocarbamoyl and decarbamoyl toxins. In order to test for any matrix effect in the quantification of those toxins, concentrations obtained from solvent and matrix matched calibration curves were compared. A suppression of the fluorescence signal was observed in mussel extract or fraction in comparison to solvent for the compounds dcGTX2?+?3, GTX2?+?3 and GTX1?+?4, while an enhancement was found for C1?+?2, dcSTX, STX, B1, dcNEO and NEO. These results showed that a matrix effect varies among compounds. The difference of concentrations between solvent and matrix matched calibration curves for C1?+?2 (median?=?421?ng?g^?1) exceeded largely the values for the other quantified compounds (0.09–58?ng?g^?1). Those differences were converted into toxicity differences, using Oshima toxicity equivalence factors. The compounds C1?+?2 and dcNEO were the major contributors to the differences of total toxicity in the mussel samples. The differences of total toxicity were calculated in ten mussel samples collected during a 10-week blooming period in Portuguese coastal lagoon. Values varied between 53 and 218?µg STX equivalents kg^?1. The positive differences mean that the estimated toxicity using solvent calibration curves exceed the values taking into account the matrix. For the toxicity interval 200–800?µg STX equivalents kg^?1 an increase was found between 44 and 28%.     

石房蛤毒素免疫亲和柱制备及柱效测试研究

目的阐明石房蛤毒素(saxitoxin, STX)免疫亲和柱对11种麻痹性贝类毒素的亲和作用。方法通过纯化的STX单克隆抗体与琼脂糖凝胶(sepharose 4B)制备STX免疫亲和柱,采用11种麻痹性贝类毒素(paralytic shellfish poisoning,PSP)标液进行过柱实验,优化上柱条件,采用液相色谱-质谱串联法进行毒素检测。结果STX免疫亲和柱对新石房蛤毒素(neosaxitoxin,neo-STX)、脱氨甲酰基新石房蛤毒素(decarbamoylneosaxitoxin dihydrochloride,dcneo-STX)、膝沟藻毒素1(gonyautoxin-1,GTX1)、膝沟藻毒素4(gonyautoxin-4, GTX4)基本没有亲和力作用;而对7种PSP的亲和力强弱顺序为:STXN-磺酰氨甲酰基类毒素5(gonyautoxin-5, GTX5)脱氨甲酰基石房蛤毒素(decarbamoylsaxitoxin dihydrochloride, dcSTX)膝沟藻毒素3(gonyautoxin-3,GTX3)脱氨甲酰基膝沟藻毒素3(decarbamoylgonyautoxin-3,dcGTX3)脱氨甲酰基膝沟藻毒素2(decarbamoylgonyautoxin-2, dcGTX2)膝沟藻毒素2(gonyautoxin-2, GTX2),其中对STX、GTX5、dcSTX、GTX3的回收率为61.2%～99.0%。结论该STX免疫亲和柱对STX、GTX5、dcSTX、GTX3有较好的吸附效果,能够满足样品检测前处理的要求,为水产品中麻痹性贝类毒素的提取方法研究提供了新技术的参考依据。     

Thermal Degradation of Partially Purified Paralytic Shellfish Poison Toxins at Different Times, Temperatures, and pH

ABSTRACT: Mixtures of purified and partially purified paralytic shellfish poisoning (PSP) toxins including C1/2 and B1 toxins, gonyautoxins 1-4 (GTX), neosaxitoxin (NEO), and saxitoxin (STX) were heated at different temperatures (90 to 130 °C), heating times (10 to 120 min), and pH (3 to 7) and analyzed by HPLC. C toxins declined rapidly at low pH, and GTX 1/4 toxins decreased at high temperatures and at high pH. GTX 2/3 increased initially at low pH and then declined with subsequent heating, whereas STX increased consistently at pH 3 to 4. The integrated total specific toxicity declined at high pH (6 to 7). The kinetics of thermal destruction were 1^st order, and the efficacy of thermal destruction was highly dependent on pH, with rapid thermal destruction of carbamate compounds at higher pH. D values of carbamate toxins decreased with increasing temperature at high pH. Heating at low pH resulted in conversion of least toxic compounds to highly toxic compounds.     

VARIED ASSAYS FOR PSP TOXINS IN HEAT SHOCKED PHILIPPINE GREEN MUSSELS (PERNA VIRIDIS)

Toxin assays namely: the mouse bioassay, the receptor binding assay (RBA) and, the immuno-chromatography assay using MIST Alert™ rapid test kit were used to determine the concentrations of Paralytic Shellfish Poisoning (PSP) toxins from untreated and heat shocked Philippine green mussels, Perna viridis contaminated with Pyrodinium bahamense var. compressum. Toxin levels ranging from 4–15 μg STXeq/100 g sample were quantified in the mussel samples analyzed using RBA. Higher levels of PSP toxins at about 30 μg STX eq/100 g sample were recorded using mouse bioassay, which was attributed to interfering factors that could induce mouse death resulting in false positive reactions. The MIST Alert™ test kit showed positive reaction in the samples evaluated based on the reported average profile of PSP toxin analogues at about 40 μg STX eq/100 g sample. The test heat treatments did not elicit definitive change in the PSP toxin profiles of heat shocked mussels relative to the untreated samples.     

Application of HPLC for the Determination of PSP Toxins in Shellfish

A high performance liquid chromatographic (HPLC) procedure for determination of the toxins associated with paralytic shellfish poisoning (PSP) is compared to the standard AOAC mouse bioassay method on 100 shellfish samples representing a variety of species. For those samples with toxin content below the detection limit of the bioassay (35 μg saxitoxin (STX)/100g) HPLC analysis indicated a similar low level with a range of <10 to 56 μg STX/100g (n = 60). A correlation coefficient of 0.92 was determined for the 40 samples exhibiting toxicity in the bioassay (i.e., >35 μg STX/100g). Among the advantages of the HPLC method over the bioassay are significantly better sensitivity, greater sample through-put, and ability to determine the levels of each individual PSP toxin.     

Toxins in toxic Taiwanese crabs

Abstract

A total of 459 specimens covering 51 species in 9 families was collected from October 1992 to May 1996 in Taiwan. All specimens were assayed for the presence of tetrodotoxin (TTX) and paralytic shellfish poison (PSP). The specimens of five xanthid crabs Zosimus aeneus, Lophozozymus pictor, Ategatopsis germaini, Atergatis floridus, and De‐mania reynaudi were found to contain potent toxins. Among them, A. germaini showed the highest toxicity. The toxin profile of each toxic crab species was as follows: 82% TTX and 18% PSP in Z. aeneus, 89% TTX and 11% PSP in L. pictor, 3% TTX and 97% PSP inA germaini, 85% TTX and 15% in A. floridus, and 88% TTX and 12% PSP in D. reynaudi. PSP was mainly composed of gonyautoxins (GTXs) 1–4 in Z. aeneus, L. pictor, and A. floridus, but GTX 3 and hydroxysaxitoxin in A. germaini, and neosaxitoxin in D. reynaudi. The PSP‐producing dinoflagellate plankton Alexandrium minutum and TTX‐producing bacteria including Vibrio alginolyticus and Vibrio parahaemolyticus were isolated and considered as the sources of the toxins.     

Development and application of an enzyme immunoassay based on a monoclonal antibody against gonyautoxin components of paralytic shellfish poisoning toxins

With a gonyautoxin 2/3 (GTX2/3)-specific monoclonal antibody (designated GT-13A) and a saxitoxin-horseradish peroxidase conjugate (STX-HRP), a direct competitive enzyme immunoassay (GTX-EIA) was established and its sensitivity to various toxin components was investigated. The concentrations resulting in 50% inhibition of the binding of STX-HRP to the solid-phase GT-13A antibody for GTX2/3, decarbamoyl-GTX2/3 (dc-GTX2/3), N-sulfocarbamoyl-GTX2/3 (C1/2), GTX1/4, STX, and neosaxitoxin (neoSTX) in GTX-EIA were found to be 0.28, 0.41, 0.52, 3.46, 4.06, and 89.37 ng/ml, respectively. When the minimum detection limit was assumed to be at a toxin concentration causing 30% inhibition of the binding of STX-HRP to the solid-phase GT-13A antibody, the detection limits for GTX2/3, dc-GTX2/3, C1/2, GTX1/4, STX, and neoSTX were found to be 0.15, 0.18, 0.19, 1.09, 1.50, and 22.93 ng/ml, respectively. These results indicate that all of the GTX components examined and STX are detectable at concentrations lower than the regulatory limit of 80 microg/100 g of shellfish tissue, even when a minimum dilution factor of 100 is applied to tissue extracts with the extraction procedure of the Association of Official Analytical Chemists. Therefore, GTX-EIA is thought to be a useful qualitative screening method for GTX components and STX in the mass monitoring of toxin-contaminated shellfish.     

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 postcolumn 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 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 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.     

2018—2020年河北省市售贝类中麻痹性贝类毒素污染状况调查分析

目的了解2018—2020年河北省市售贝类中麻痹性贝类毒素(paralytic shellfish poison,PSP)污染状况。方法 2018年8月—2020年5月间,对河北省市售的7种双壳贝类,共508份进行检测分析。样品经0.5%乙酸水提取,石墨化碳黑固相萃取柱净化,采用高效液相色谱-串联质谱法进行检测。结果 508份样品,PSP阳性样品24份,检出率为4.7%, 15份样品超过世界卫生组织规定安全限量,超标率为3.0%。检出贝类为贻贝、毛蚶、杂色蛤、扇贝, PSP含量范围分别为217.0~13001.8μg石房蛤毒素当量(saxitoxin equivalent, STXeq/kg)、217.0~4893.2μg STXeq/kg、217.0~503.6μg STXeq/kg、217.0~11024.5μg STXeq/kg;超标贝类为贻贝、毛蚶、扇贝。贝类中检出的PSP类型有GTX1、GTX4、GTX2、GTX3、neoSTX、STX。结论河北省市售贝类麻痹性贝类毒素暴露风险整体较低,秦皇岛地区贻贝等贝类产品在4、5月份较易受到PSP污染,应持续关注,加强早期监测预警。     

Receptor binding assay for the detection of paralytic shellfish poisoning toxins: comparison to the mouse bioassay and applicability under regulatory use

The receptor-binding assay (RBA) method for the detection of paralytic shellfish poisoning (PSP) toxins was evaluated for its overall performance in comparison with the mouse bioassay (MBA). An initial study to evaluate the effects of filtering shellfish extracts prior to running the RBA indicated no significant difference between filtered and unfiltered extracts on the determined saxitoxin (STX) concentrations. Next, we tested the RBA assay on 295 naturally contaminated mussel tissue samples, ranging in concentrations from 320 µg STX equiv. kg^?1 to 13,000 µg STX equiv. kg^?1 by MBA. An overall trend was observed with the RBA giving higher results (256 µg STX equiv. kg^?1 on average) than the MBA; however, at low concentrations (< 500 µg STX equiv. kg^?1) the RBA results were marginally lower. A third study was conducted using spiked mussel tissue analysed by three independent laboratories, two of which performed the RBA and one the MBA. This multi-laboratory study again showed the RBA to give higher results than the MBA; however, it also revealed that STX determination was accurate by the RBA, unlike the MBA. To optimise the assay for efficient usage under regulatory practice, three suggestions have been made: the use of an initial screening plate to separate those samples that exceed the alert level; use of rapid PSP test kits in the field and in the laboratory for screening negative samples and for early detection of toxicity; and use of an alternate commercially available porcine membrane in place of the laboratory-prepared rat membrane homogenate. The large number of samples analysed and the diversity of the tests conducted in this study further support the RBA as an affordable rapid method for STX detection that is also free of the routine sacrifice of live animals.     

Accumulation and elimination profiles of paralytic shellfish poison in the short-necked clam Tapes japonica fed with the toxic dinoflagellate Gymnodinium catenatum

The paralytic shellfish poison (PSP)-producing dinoflagellate Gymnodinium catenatum (Gc) was fed to the short-necked clam Tapes japonica, and the accumulation, transformation and elimination profiles of PSP were investigated by means of high-performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD). The short-necked clams ingested most of the Gc cells (4 x 10(6) cells) supplied as a bolus at the beginning of the experiment, and accumulated a maximal amount of toxin (181 nmol/10 clams) after 12 hr. The rate of toxin accumulation at that time was 16%, which rapidly decreased thereafter. During the rearing period, a variation in toxin composition, derived presumably from the transformation of toxin analogues in the clams, was observed, including a reversal of the ratio of C2 to C1, and the appearance of carbamate (gonyautoxin (GTX) 2, 3) and decarbamoyl (dc) derivatives (decarbamoylsaxitoxin (dcSTX) and dcGTX2, 3), which were undetectable in Gc cells. The total amount of toxin contained in clams and residue (remaining Gc cells and/or excrement in the rearing tank) gradually declined, and only about 1% of the supplied toxin was detected at the end of the experiment.     

Effects of exogenous polyamines on growth,toxicity, and toxin profile of dinoflagellate Alexandrium minutum

The effect of exogenous polyamines (cadaverine, putrescine, norspermidine, spermidine, and spermine) on the growth, toxicity, and toxin profile of the dinoflagellate Alexandrium minutum T1 was examined. It was found that cadaverine at concentrations of 0.1-2.0 mumol/L enhanced the growth of A. minutum T1. Putrescine and norspermidine at a low level (0.1 mumol/L) also promoted the algal growth. Spermidine depressed the algal growth. However, the cell toxicity levels of A. minutum T1 cultured with or without cadaverine, putrescine, norspermidine, and spermidine were almost the same. The toxic components of A. minutum T1 were GTXs 1-4 only, and GTXs 1 and 4 were predominant (74.6 +/- 7.1%) in all cultures. On the other hand, spermine did not effect the growth of A. minutum T1, though it decreased the cell toxicity and the ratio of GTX 2 + GTX 3 (15.0 +/- 6.6%).     

Analysis of paralytic shellfish toxins and their metabolites in shellfish from the North Yellow Sea of China

Samples of toxic scallop (Patinopecten yessoensis) and clam (Saxidomus purpuratus) collected on the northern coast of China from 2008 to 2009 were analysed. High-performance liquid chromatography with post-column oxidation and fluorescence detection was used to determine the profile of the main paralytic shellfish poisoning (PSP) toxins in these samples and their total toxicity. Hydrophilic interaction liquid ion chromatography with mass spectrometric detection confirmed the toxin profile and detected several metabolites in the shellfish. Results show that C1/2 toxins were the most dominant toxins in the scallop and clam samples. However, GTX1/4 and GTX2/3 were also present. M1 was the predominant metabolite in all the samples, but M3 and M5 were also identified, along with three previously unreported presumed metabolites, M6, M8 and M10. The results indicate that the biotransformation of toxins was species specific. It was concluded that the reductive enzyme in clams is more active than in scallops and that an enzyme in scallops is more apt to catalyse hydrolysis of both the sulfonate moiety at the N-sulfocabamoyl of C toxins and the 11-hydroxysulfate of C and GTX toxins to produce metabolites. This is the first report of new metabolites of PSP toxins in scallops and clams collected in China.     

Effect of PSP toxins in white leg shrimp Litopenaeus vannamei Boone, 1931

ABSTRACT:  Cultured shrimp are often exposed to different toxic products during rearing practices that may affect survival and quality of the product. An evaluation of the effects of paralytic shellfish toxins (PSP) from species of Gymnodinium catenatum in white leg shrimp ( Litopenaeus vannamei ) has been carried out in this study. Death was observed at doses > 5.0 MU (equivalent to 1.1 μg/g of STX), while lower doses provoked paralysis of pereiopods, disequilibrium, and abdominal spasms in the animals. Target organs such as the heart and brain were severely damaged, with cohesion loss and cell density reduction evidenced by histological analysis. Hence, pond productivity and quality of the harvested organisms may be affected by PSP toxins. This is the 1st report on the effect of PSP toxins from G. catenatum in white eg shrimp.     

Occurrence of tetrodotoxin and paralytic shellfish poisons in a gastropod implicated in food poisoning in southern Taiwan

The toxicity of the gastropod Nassarius papillosus implicated in a food paralytic poisoning incident in Liuchiu Island, Taiwan, in October 2005 is reported. The symptoms of a victim (67 years old) were featured by general paresthesia, paralysis of phalanges and extremities, paralysis, coma, and aphasia. The remaining specimens of shell were assayed for toxicity. The range of specimen toxicity was found to be 63-474 mouse units (MU) per specimen for N. papillosus by a tetrodotoxin (TTX) bioassay. The mean (SD) toxicity of the digestive gland and other portions were 296 ± 120 and 382 ± 156 MU in N. papillosus. The toxin was partially purified from the acidic methanol extract of the gastropod by using a C18 solid-phase extraction column. The eluate was then filtered through a 3000 MW cut-off ultrafree microcentrifuge filter. It was shown that the toxin purified from gastropods analysed by high-performance liquid chromatography and liquid chromatography/mass spectrometry contained TTX 42-60 µg g^-1 (about 90%), whereas along with minor paralytic shellfish poisons (PSP) it was 3-6 µg g^-1 (about 10%).     

Analysis of paralytic shellfish toxins and their metabolites in shellfish from the North Yellow Sea of China

Samples of toxic scallop (Patinopecten yessoensis) and clam (Saxidomus purpuratus) collected on the northern coast of China from 2008 to 2009 were analysed. High-performance liquid chromatography with post-column oxidation and fluorescence detection was used to determine the profile of the main paralytic shellfish poisoning (PSP) toxins in these samples and their total toxicity. Hydrophilic interaction liquid ion chromatography with mass spectrometric detection confirmed the toxin profile and detected several metabolites in the shellfish. Results show that C1/2 toxins were the most dominant toxins in the scallop and clam samples. However, GTX1/4 and GTX2/3 were also present. M1 was the predominant metabolite in all the samples, but M3 and M5 were also identified, along with three previously unreported presumed metabolites, M6, M8 and M10. The results indicate that the biotransformation of toxins was species specific. It was concluded that the reductive enzyme in clams is more active than in scallops and that an enzyme in scallops is more apt to catalyse hydrolysis of both the sulfonate moiety at the N-sulfocabamoyl of C toxins and the 11-hydroxysulfate of C and GTX toxins to produce metabolites. This is the first report of new metabolites of PSP toxins in scallops and clams collected in China.