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1.
Chemosphere ; 261: 128063, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113659

RESUMO

Paralytic shellfish toxins (PSTs) are a group of natural toxic substances often found in marine bivalves. Accumulation, anatomical distribution, biotransformation and depuration of PSTs in different tissues of bivalves, however, are still not very well understood. In this study, we investigated biokinetics and biotransformation of PSTs in six different tissues, namely gill, mantle, gonad, adductor muscle, kidney, and digestive gland, in Yesso scallops Patinopecten yessoensis exposed to a toxic strain of dinoflagellate Alexandrium pacificum. High daily accumulation rate (DAR) was recorded at the beginning stage of the experiment. Most of the PSTs in toxic algae ingested by scallops were retained and the toxicity level of PSTs in scallops exceeded the regulatory limit within 5 days. At the late stage of the experiment, however, DAR decreased obviously due to the removal of PSTs. Fitting results of the biokinetics model indicated that the amount of PSTs transferred from digestive gland to mantle, adductor muscle, gonad, kidney, and gill in a decreasing order, and adductor muscle, kidney, and gonad had higher removal rate than gill and mantle. Toxin profile in digestive gland was dominated by N-sulfocarbamoyl toxins 1/2 (C1/2), closely resembled that of the toxic algae. In contrast, toxin components in kidney were dominated by high-potency neosaxitoxin (NEO) and saxitoxin (STX), suggesting that the kidney be a major organ for transformation of PSTs.


Assuntos
Dinoflagelados/metabolismo , Pectinidae/efeitos dos fármacos , Pectinidae/metabolismo , Saxitoxina/análogos & derivados , Poluentes Químicos da Água/metabolismo , Animais , Bioacumulação , Biotransformação , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Saxitoxina/metabolismo , Saxitoxina/toxicidade , Toxicocinética , Poluentes Químicos da Água/toxicidade
2.
Mar Pollut Bull ; 157: 111333, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32658697

RESUMO

Paralytic shellfish toxins (PSTs) cause risks to human health through food chains. Understanding the change of PSTs in seawater is critical for predicting the safety of seafood. Most reported methods for the detection of PSTs in microalgae or shellfish are not applicable in seawater because of extremely low concentration and matrix interferences. High resolution mass spectrometry (HRMS), quadrupole exactive orbitrap detects molecular ions accurately, and molecularly imprinted solid-phase extraction (MISPE) is recognized effective to reduce the matrix interference. GTXs 2&3 are two of common marine toxins in PSTs. In this study, a sensitive method consisting MISPE and liquid chromatography LC-HRMS was developed for the detection of GTXs 2&3 with a limit of detection (LOD) of 47.4 ng/L in seawater. With this method, samples obtained from the estuaries of the Shuangtaizi and Daliao Rivers were analyzed, and the results indicated the concentrations were lower than LOD in the area under investigation.


Assuntos
Impressão Molecular , Polímeros , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Humanos , Espectrometria de Massas , Saxitoxina/análogos & derivados , Água do Mar , Extração em Fase Sólida
3.
Artigo em Inglês | MEDLINE | ID: mdl-32026312

RESUMO

Individuals of Mytilus platensis were exposed to Alexandrium catenella to evaluate the accumulation and metabolization of paralytic shellfish toxins (PST) over a period of 25 days. Mussels were collected from the intertidal zone of Cerro Avanzado, Argentine Patagonia. After 16 days, the toxins in the tissues of mussels were detected by the methods of mouse bioassay and high performance liquid chromatography with fluorometric detection (HPLC-FDL). The accumulation kinetics of PST toxins in M. platensis fed with A. catenella fitted to a linear function, in which the accumulation rate was 31.2 µg STX eq kg-1 day-1. After 16 days, the PST toxin level in tissues of mussels reached 1178 µg STX eq kg-1 exceeding the safety limit for human consumption (800 µg STX eq kg-1 tissue), whereas the highest PST toxin level was reached at the end of the experimentation (1613 µg STX eq kg-1) at 25 days. Differences in the toxin profile of the dinoflagellates and the tissues of the mussels confirmed biotransformation of PST in the mussel digestive system. The toxin profile of M. platensis was dominated by the gonyautoxins GTX1 and GTX4, while the toxin profile of A. catenella was dominated by the N-sulfocarbamoyl toxin C2. To our knowledge, this is the first experimentation on a laboratory scale of PST toxins accumulation in M. platensis with a native strain of A. catenella of Argentine Patagonia.


Assuntos
Dinoflagelados/fisiologia , Toxinas Marinhas , Mytilus/fisiologia , Animais , Argentina , Bioensaio , Saxitoxina/análogos & derivados , Alimentos Marinhos
4.
J Endocrinol ; 244(3): 523-533, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31958316

RESUMO

A high sympathetic tone is observed in the development and maintenance of the polycystic ovary (PCO) phenotype in rats. Neosaxitoxin (NeoSTX) specifically blocks neuronal voltage-dependent Na+ channels, and we studied the capacity of NeoSTX administered into the ovary to block sympathetic nerves and PCO phenotype that is induced by estradiol valerate (EV). The toxin was administered with a minipump inserted into the bursal cavity using two protocols: (1) the same day as EV administration and (2) 30 days after EV to block the final step of cyst development and maintenance of the condition. We studied the estrous cycling activity, follicular morphology, steroid plasma levels, and norepinephrine concentration. NeoSTX administered together with EV decreased NA intraovarian levels that were induced by EV, increased the number of corpora lutea, decreased the number of follicular cyst found after EV administration, and decreased the previously increased testosterone plasma levels induced by the PCO phenotype. Estrous cycling activity also recovered. NeoSTX applied after 30 days of EV administration showed near recovery of ovary function, suggesting that there is a specific window in which follicular development could be protected from cystic development. In addition, plasma testosterone levels decreased while those of progesterone increased. Our data strongly suggest that chronic inhibition of sympathetic nerves by a locally applied long-lasting toxin is a new tool to manage the polycystic phenotype in the rat and could be applied to other mammals depending on sympathetic nerve activity.


Assuntos
Ovário/inervação , Síndrome do Ovário Policístico/prevenção & controle , Saxitoxina/análogos & derivados , Sistema Nervoso Simpático/efeitos dos fármacos , Animais , Dinoflagelados/química , Estradiol/sangue , Ciclo Estral , Estro/metabolismo , Feminino , Humanos , Norepinefrina/sangue , Ovário/efeitos dos fármacos , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/fisiopatologia , Progesterona/sangue , Ratos , Ratos Sprague-Dawley , Saxitoxina/administração & dosagem , Sistema Nervoso Simpático/fisiopatologia
5.
Chemosphere ; 238: 124661, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472350

RESUMO

Toxicities of the marine algae Alexandrium minutum and its excreted gonyautoxins (GTXs) to the marine crustacean Artemia salina were investigated. Mortality was observed for neither larvae nor adult A. salina exposed to A. minutum at a density of 5000 cells/mL or 0.5 µM GTX2/3. After exposure, the full transcriptome of adult A. salina was assembled and functionally annotated. A total of 599,286 transcripts were obtained, which were clustered into 515,196 unigenes. Results of the transcriptional effect level index revealed that direct exposure to the toxic algae A. minutum caused greater alterations in the transcriptome than did exposure to the extracellular product GTX2/3. Mechanisms of effects were different between exposure of A. salina to A. minutum cells or GTX2/3. Exposure to A. minutum modulated formation of the ribonucleoprotein complex and metabolism of amino acids and lipids in A. salina. Exposure to GTX2/3 exposure inhibited expression of genes related to metabolism of chitin, which might result in disruption of molting process or disturbed sheath morphogenesis. Overall, effects on transcription observed in this study represent the first report based on application of next generation sequencing techniques to investigate the transcriptomic response of A. salina exposed to an environmentally realistic level of A. minutum or GTX2/3.


Assuntos
Artemia/genética , Saxitoxina/análogos & derivados , Transcriptoma/efeitos dos fármacos , Animais , Artemia/fisiologia , Quitina/genética , Quitina/metabolismo , Dinoflagelados/citologia , Dinoflagelados/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Saxitoxina/farmacologia , Saxitoxina/toxicidade
6.
Mar Drugs ; 17(12)2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31766477

RESUMO

Paralytic shellfish toxins (PSTs) are the major neurotoxic contaminants of edible bivalves in Japan. Tetrodotoxin (TTX) was recently detected in bivalve shellfish around the world, drawing widespread attention. In Japan, high levels of TTX were reported in the digestive gland of the scallop, Patinopecten yessoensis, in 1993; however, no new data have emerged since then. In this study, we simultaneously analyzed PSTs and TTX in scallops cultured in a bay of east Japan using hydrophilic interaction chromatography (HILIC)-MS/MS. These scallops were temporally collected from April to December 2017. The highest concentration of PSTs (182 µmol/kg, total congeners) in the hepatopancreas was detected in samples collected on May 23, lined to the cell density of the dinoflagellate, Alexandrium tamarense, in seawater around the scallops, whereas the highest concentration of TTX (421 nmol/kg) was detected in samples collected on August 22. Contrary to the previous report, temporal variation of the PSTs and TTX concentrations did not coincide. The highest concentration of TTX in the entire edible tissues was 7.3 µg/kg (23 nmol/kg) in samples obtained on August 22, which was lower than the European Food Safety Authority (EFSA)-proposed threshold, 44 µg TTX equivalents/kg shellfish meat. In addition, 12ß-deoxygonyautoxin 3 was firstly identified in scallops.


Assuntos
Dinoflagelados/química , Pectinidae/química , Saxitoxina/análogos & derivados , Alimentos Marinhos/análise , Tetrodotoxina/análise , Animais , Aquicultura , Baías , Cromatografia Líquida de Alta Pressão , Japão , Saxitoxina/análise , Saxitoxina/toxicidade , Estações do Ano , Água do Mar/microbiologia , Intoxicação por Frutos do Mar/etiologia , Intoxicação por Frutos do Mar/prevenção & controle , Espectrometria de Massas em Tandem , Tetrodotoxina/toxicidade , Fatores de Tempo
7.
Toxicon ; 167: 76-81, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31170406

RESUMO

To understand phycotoxin contamination in shellfish in the sub-Arctic and Arctic areas, scanning for the presence of 13 hydrophilic and lipophilic toxin components each was by liquid chromatography tandem quadrupole mass spectrometry analysis in shellfish samples collected from the Northern Bering Sea and the Chukchi Sea in 2014. The results showed that shellfish collected in both areas werecontaminated to different extents. Saxitoxin (STX), decarbamoylsaxitoxin (dcSTX) and decarbamoylneosaxitoxin (dcNEO) were the most frequently detected hydrophilic components, with maximum concentrations of 90.1 µg/kg, 112.25 µg/kg and 23.09 µg/kg, respectively. Although gonyautoxins (GTXs) were only detected in 3 samples, they were the main contributors to overall toxicity of high-latitude samples, especially GTX1. For lipophilic toxins, spirolide-1 (SPX1) and yessotoxin (YTX) were present in all samples at low levels (< 7 µg/kg and < 50 µg/kg, respectively). Only 5 samples showed evidence of okadaic acid (OA) and dinophysistoxin-2 (DTX-2) at low concentrations, ranging from 0.42 µg/kg to 7.23 µg/kg and 3.03 µg/kg to 30.59 µg/kg, respectively. Notably, a high level of pectenotoxin-1 (PTX-1) at 467.40 µg/kg was found in the shellfish collected at the northernmost station, exceeding the safety regulation standard by nearly 3 times. For both lipophilic and hydrophilic toxins, contamination in shellfish in the sub-Arctic and the Arctic area may be much more widespread and severe than was previously thought. This study highlighted the need to monitor toxins in a wider variety of shellfish, especially economic or commercial species, and across a wider range of sub-Arctic and Arctic waters, as well as the potential sources of these toxins.


Assuntos
Contaminação de Alimentos/análise , Saxitoxina/análise , Frutos do Mar , Regiões Árticas , Cromatografia Líquida , Saxitoxina/análogos & derivados , Saxitoxina/química , Espectrometria de Massas em Tandem
8.
Toxicon ; 164: 26-30, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30951754

RESUMO

OBJETIVE: To evaluate Neosaxitoxin (NeoSTX) as a local anesthetic drug, for pain control during and after piglet castration. STUDY DESIGN: Prospective, randomized and double-blind study. ANIMALS: 24 commercial hybrids, males, 23-day-old piglets. METHODS: The piglets were randomized into two groups: a Lidocaine group and a NeoSTX group. One minute before castration, they were injected intra-scrotally with a single dose of Lidocaine (20 mg, in 1 mL) and NeoSTX (0.1 µg, in 1 mL), respectively. RESULTS: NeoSTX does not generate vasoconstriction or scrotal contraction, unlike Lidocaine, where a decrease in temperature and scrotal size is observed within 5 min after the procedure. After 24 h, wound inflammation, as measured by scrotal size, was lower in the NeoSTX group. No significant difference could be shown between the vocalizations and facial expressions of pain of both groups during the castration procedure. CONCLUSIONS: A single dose of NeoSTX is safe and effective for pain management during and after piglet castration. NeoSTX treated piglets were less affected by castration than those in the Lidocaine group, thus reducing piglet stress and enhancing the quality of piglet convalescence.


Assuntos
Anestésicos Locais/administração & dosagem , Dor/tratamento farmacológico , Saxitoxina/análogos & derivados , Sus scrofa/fisiologia , Animais , Inflamação/tratamento farmacológico , Lidocaína/administração & dosagem , Masculino , Orquiectomia/veterinária , Estudos Prospectivos , Distribuição Aleatória , Saxitoxina/administração & dosagem , Escroto/efeitos dos fármacos , Temperatura Cutânea/efeitos dos fármacos
9.
Mar Drugs ; 18(1)2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31888062

RESUMO

Voltage-gated sodium channels (NaVs) are membrane proteins that are involved in the generation and propagation of action potentials in neurons. Recently, the structure of a complex made of a tetrodotoxin-sensitive (TTX-s) NaV subtype with saxitoxin (STX), a shellfish toxin, was determined. STX potently inhibits TTX-s NaV, and is used as a biological tool to investigate the function of NaVs. More than 50 analogs of STX have been isolated from nature. Among them, zetekitoxin AB (ZTX) has a distinctive chemical structure, and is the most potent inhibitor of NaVs, including tetrodotoxin-resistant (TTX-r) NaV. Despite intensive synthetic studies, total synthesis of ZTX has not yet been achieved. Here, we review recent efforts directed toward the total synthesis of ZTX, including syntheses of 11-saxitoxinethanoic acid (SEA), which is considered a useful synthetic model for ZTX, since it contains a key carbon-carbon bond at the C11 position.


Assuntos
Saxitoxina/análogos & derivados , Bloqueadores do Canal de Sódio Disparado por Voltagem/síntese química , Animais , Saxitoxina/síntese química , Saxitoxina/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/química
10.
Toxins (Basel) ; 10(11)2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30373104

RESUMO

Paralytic shellfish poisoning (PSP) is a severe food-borne illness, caused by the ingestion of seafood containing paralytic shellfish toxins (PST), which are naturally produced by marine dinoflagellates and accumulate in shellfish during algae blooms. Novel PST, designated as hydroxybenzoate analogues (also known as GC toxins), was relatively recently discovered in Gymnodinium catenatum strains worldwide. However, to date, there have been no studies examining their accumulation in shellfish. In this study, mussels (Mytilus galloprovincialis) were exposed to G. catenatum for five days and then exposed to a non-toxic diet for 24 h, to investigate the toxin's accumulation/elimination dynamics. As determined by UHPLC-HILIC-MS/MS, the hydroxybenzoate analogues, GC1 to GC6, comprised 41% of the algae toxin profile and only 9% in mussels. Elimination of GC toxins after 24 h was not evident. This study highlights that a relevant fraction of PST in mussels are not routinely analysed in monitoring programs and that there is a need to better understand the toxicological potential of the hydroxybenzoate analogues, in order to properly address the risk of G. catenatum blooms.


Assuntos
Dinoflagelados , Hidroxibenzoatos/análise , Mytilus/metabolismo , Saxitoxina/análogos & derivados , Saxitoxina/análise , Animais , Cromatografia Líquida de Alta Pressão , Hidroxibenzoatos/metabolismo , Saxitoxina/metabolismo , Intoxicação por Frutos do Mar , Espectrometria de Massas em Tandem
11.
ACS Chem Biol ; 13(11): 3107-3114, 2018 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-30296060

RESUMO

The neurotoxin saxitoxin and related paralytic shellfish toxins are produced by multiple species of cyanobacteria and dinoflagellates. This study investigates the two saxitoxin-producing strains of Scytonema crispum, CAWBG524 and CAWBG72, isolated in New Zealand. Each strain was previously reported to have a distinct paralytic shellfish toxin profile, a rare observation between strains within the same species. Sequencing of the saxitoxin biosynthetic clusters ( sxt) from S. crispum CAWBG524 and S. crispum CAWBG72 revealed the largest sxt gene clusters described to date. The distinct toxin profiles of each strain were correlated to genetic differences in sxt tailoring enzymes, specifically the open-reading frame disruption of the N-21 sulfotransferase sxtN, adenylylsulfate kinase sxtO, and the C-11 dioxygenase sxtDIOX within S. crispum CAWBG524 via genetic insertions. Heterologous overexpression of SxtN allowed for the proposal of saxitoxin and 3'-phosphoadenosine 5'-phosphosulfate as substrate and cofactor, respectively, using florescence binding assays. Further, catalytic activity of SxtN was confirmed by the in vitro conversion of saxitoxin to the N-21 sulfonated analog gonyautoxin 5, making this the first known report to biochemically confirm the function of a sxt tailoring enzyme. Further, SxtN could not convert neosaxitoxin to its N-21 sulfonated analog gonyautoxin 6, indicating paralytic shellfish toxin biosynthesis most likely occurs along a predefined route. In this study, we identified key steps toward the biosynthetic conversation of saxitoxin to other paralytic shellfish toxins.


Assuntos
Família Multigênica , Neurotoxinas/classificação , Neurotoxinas/genética , Saxitoxina/classificação , Saxitoxina/genética , Cianobactérias/genética , Dioxigenases/genética , Genes Bacterianos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Neurotoxinas/química , Fosfoadenosina Fosfossulfato/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Filogenia , Ligação Proteica , Saxitoxina/análogos & derivados , Saxitoxina/síntese química , Saxitoxina/química , Sulfotransferases/química , Sulfotransferases/genética , Sulfotransferases/metabolismo , Transposases/genética
12.
Toxins (Basel) ; 10(9)2018 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-30200645

RESUMO

Paralytic shellfish toxins (PSTs) are potent alkaloids of microalgal and cyanobacterial origin, with worldwide distribution. Over the last 20 years, the number of poisoning incidents has declined as a result of the implementation of legislation and monitoring programs based on bivalves. In the summer of 2012 and 2013, we collected a total of 98 samples from 23 different species belonging to benthic and subtidal organisms, such as echinoderms, crustaceans, bivalves, and gastropods. The sampling locations were Madeira, São Miguel Island (Azores archipelago), and the northwestern coast of Morocco. The samples were analyzed using post-column oxidation liquid chromatography with a fluorescence detection method. Our main goal was to detect new vectors for these biotoxins. After reporting a total of 59 positive results for PSTs with 14 new vectors identified, we verified that some of the amounts exceeded the limit value established in the EU. These results suggest that routine monitoring of saxitoxin and its analogs should be extended to more potential vectors other than bivalves, including other edible organisms, for a better protection of public health.


Assuntos
Invertebrados , Saxitoxina/análogos & derivados , Saxitoxina/análise , Poluentes da Água/análise , Animais , Oceano Atlântico , Monitoramento Ambiental , Peixes , Intoxicação por Frutos do Mar
13.
J Neurosci Methods ; 308: 197-204, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30107206

RESUMO

BACKGROUND: Neosaxitoxin (NeoSTX) and related paralytics shellfish toxins has been successfully used as local anesthetic and muscle relaxants to treat a variety of ailments. The primary mechanism of action of these toxins occurs by blocking voltage-gated sodium channels with compounds such as TTX, lidocaine, or derivatives. However, most of these non-classical sodium channel blockers act with a reduced time effect as well as ensuing neurotoxicity. NEW METHOD: In this report, we show that the use of local NeoSTX injections inactivates the hippocampal neuronal activity reversibly with a by long-term dynamics, without neuronal damage. RESULTS: A single 10 ng/µl injection of NeoSTX in the dorsal CA1 region abolished for up to 48 h memory capacities and neuronal activity measured by the neuronal marker c-fos. After 72 h of toxin injection, the animals fully recover their memory capacities and hippocampal neuronal activity. The histological inspection of NeoSTX injected brain regions revealed no damage to the tissue or reactive gliosis, similar to vehicle injection. Acute electrophysiological recording in vivo shows, also, minimal spreading of the NeoSTX in the cerebral tissue. COMPARISON WITH EXISTING METHODS: Intracerebral NeoSTX injection showed longer effects than other voltage sodium channel blocker, with minimal spreading and no neuronal damage. CONCLUSION: NeoSTX is a new useful tool that reversibly inactivates different brains region for a long time, with minimal diffusion and without neuronal damage. Moreover, NeoSTX can be used as a valuable sodium channel blocker for many studies in vivo and with potential therapeutic uses.


Assuntos
Região CA1 Hipocampal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Saxitoxina/análogos & derivados , Bloqueadores dos Canais de Sódio/administração & dosagem , Memória Espacial/efeitos dos fármacos , Amnésia/induzido quimicamente , Animais , Região CA1 Hipocampal/fisiologia , Masculino , Neurônios/fisiologia , Ratos Sprague-Dawley , Reconhecimento Psicológico/efeitos dos fármacos , Saxitoxina/administração & dosagem
14.
J Anal Toxicol ; 42(7): e61-e64, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29800291

RESUMO

A case of an elderly female with suspected paralytic shellfish poisoning (PSP) is presented. The patient shared a meal of recreationally-harvested shellfish with her family and soon began to experience nausea and weakness. She was taken to the local emergency department and then transported to a larger hospital in Anchorage where she was admitted to the intensive care unit with respiratory depression and shock. Her condition improved, and she was discharged from the hospital 6 days later. No others who shared the meal reported symptoms of PSP. A clam remaining from the meal was collected and analyzed for paralytic shellfish toxins (PST) by the Alaska Department of Environmental Conservation Environmental Health Laboratory; the clam tested positive for saxitoxin (STX; 277 µg/100 g), neosaxitoxin (NEO; 309 µg/100 g), multiple gonyautoxins (GTX; 576-2490 µg/100 g), decarbamoyl congeners (7.52-11.3 µg/100 g) and C-toxins (10.8-221 µg/100 g) using high-pressure liquid chromatography with post-column oxidation (AOAC Method 2011.02). Urine from the patient was submitted to Centers for Disease Control for analysis of selected PSTs and creatinine. STX (64.0 µg/g-creatinine), NEO (60.0 µg/g-creatinine) and GTX1-4 (492-4780 µg/g-creatinine) were identified in the urine using online solid phase extraction with HPLC and tandem mass spectrometry. This was the first time GTX were identified in urine of a PSP case from Alaska, highlighting the need to include all STX congeners in testing to protect the public's health through a better understand of PST toxicity, monitoring and prevention of exposures.


Assuntos
Bivalves/química , Análise de Alimentos/métodos , Saxitoxina/análogos & derivados , Intoxicação por Frutos do Mar/urina , Animais , Cromatografia Líquida de Alta Pressão , Feminino , Humanos , Saxitoxina/urina , Intoxicação por Frutos do Mar/diagnóstico , Extração em Fase Sólida , Espectrometria de Massas em Tandem , Urinálise
15.
Food Res Int ; 108: 274-279, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29735058

RESUMO

Paralytic shellfish poisoning is caused by saxitoxin and its analogues. The paralytic shellfish toxins (PSTs) are produced by marine dinoflagellates and can be accumulated in filter feeding shellfish, such as mussel, clam, oyster and ark shell. The worldwide regulatory limits for PSTs in shellfish are set at 80 µg STX eq./100 g meat and this is widely accepted as providing adequate public health protection. In this study, we have determined five individual PSTs (STX, GTX1, GTX2, GTX3 and GTX4) in shellfish using LC-MS/MS and assessed the human acute and chronic exposures to PSTs through shellfish consumption. Food consumption data was obtained from the Korea National Health and Nutrition Examination Survey (KNHANES 2010-2015). The acute exposure using a large portion size of 88 g/day (95th percentile for consumers only) with maximum toxin level of 198.7 µg/kg was 0.30 µg/kg bw. Even though we estimated the acute exposure with a conservative manner, it was below the ARfDs (0.5 or 0.7 µg STX eq./kg bw) proposed by the international organizations, representing 43-60% of the ARfDs. The chronic exposures using mean consumption data for whole population with mean concentration of PSTs were ranged from 0.002 to 0.026 µg STX eq./kg bw/day. For consumers only, the chronic exposures were in the range of 0.012-0.128 µg STX eq./kg bw/day.


Assuntos
Toxinas Bacterianas/análise , Exposição Dietética , Análise de Alimentos/métodos , Saxitoxina/análise , Alimentos Marinhos/análise , Intoxicação por Frutos do Mar/etiologia , Frutos do Mar/análise , Adolescente , Adulto , Idoso , Toxinas Bacterianas/efeitos adversos , Criança , Pré-Escolar , Cromatografia Líquida , Exposição Dietética/efeitos adversos , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , República da Coreia , Medição de Risco , Fatores de Risco , Saxitoxina/efeitos adversos , Saxitoxina/análogos & derivados , Alimentos Marinhos/efeitos adversos , Frutos do Mar/efeitos adversos , Intoxicação por Frutos do Mar/diagnóstico , Espectrometria de Massas em Tandem , Fatores de Tempo , Adulto Jovem
16.
Toxicon ; 148: 132-142, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29705145

RESUMO

Aphanizomenon gracile is one of the most widespread Paralytic Shellfish Toxin (PST) producing cyanobacteria in freshwater bodies in the Northern Hemisphere. It has been shown to produce various PST congeners, including saxitoxin (STX), neosaxitoxin (NEO), decarbamoylsaxitoxin (dcSTX) and gonyautoxin 5 (GTX5) in Europe, North America and Asia. Three cyanobacteria strains were isolated in Lake Iznik in northwestern Turkey. Morphological characterization of these strains suggested all three strains conformed to classical taxonomic identification of A. gracile with some differences such as clumping of filaments, partially hyaline cells in some filaments and longer than usual vegetative cells. Sequences of 16S rRNA gene of these strains were placed within an A. gracile cluster including the majority of PST producing strains, confirming the identification of these strains as A. gracile. These new strains possessed saxitoxin biosynthesis genes sxtA, sxtG and their sequences clustered with those of other A. gracile. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis demonstrated the presence of NEO, STX, dcSTX and decarbamoylneosaxitoxin (dcNEO) in all strains. This is the first report of a PST producer in any water body in Turkey and first observation of dcNEO in an A. gracile culture.


Assuntos
Aphanizomenon/genética , Saxitoxina/análogos & derivados , Saxitoxina/genética , Aphanizomenon/química , Aphanizomenon/classificação , Genes Bacterianos , Lagos/microbiologia , Filogenia , RNA Ribossômico 16S/genética , Saxitoxina/biossíntese , Análise de Sequência de DNA , Turquia
17.
Toxicon ; 148: 155-164, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29705148

RESUMO

A receptor binding assay (RBA) for the determination of paralytic shellfish poisoning toxicity is formally validated through collaborative study and approved for regulatory monitoring use in the US for mussels and clams. However, to date, the method has not been tested on bivalve molluscs originating from European waters and no validation studies have been conducted for oysters, a shellfish species of great importance globally. This study firstly reports the work conducted to assess the performance of the assay in comparison with a regulatory chemical detection method for a range of shellfish species originating from Great Britain. Data obtained showed a complete absence of false negative RBA results, with a tendency to over-estimate PSP toxicity for some shellfish species in comparison with liquid chromatography with fluorescence detection. Secondly, the performance of the RBA was assessed for oysters, with the analysis of a dilution series of oyster matrix certified reference materials. Method trueness, sensitivity and precision were found to compare well with results reported previously for other species. In addition, the RBA analysis of untreated and demetallated oyster extracts, provided good evidence that the RBA is not suppressed in the presence of high concentrations of zinc as reported previously for the mouse bioassay. Consequently, there is strong evidence from this study, that the RBA would be suitable for determination of PSP toxicity in bivalve molluscs from GB, with acceptable method performance in oysters. Further validation studies would be required for other shellfish species of interest before the method can be considered suitable for implementation in Europe.


Assuntos
Bioensaio , Bivalves/química , Toxinas Marinhas/análise , Animais , Ostreidae/química , Ratos , Reprodutibilidade dos Testes , Saxitoxina/análogos & derivados , Saxitoxina/análise , Frutos do Mar/análise , Intoxicação por Frutos do Mar , Reino Unido , Zinco/química
18.
Talanta ; 181: 380-384, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29426529

RESUMO

Potentiometric chemical sensors for the detection of paralytic shellfish toxins have been developed. Four toxins typically encountered in Portuguese waters, namely saxitoxin, decarbamoyl saxitoxin, gonyautoxin GTX5 and C1&C2, were selected for the study. A series of miniaturized sensors with solid inner contact and plasticized polyvinylchloride membranes containing ionophores, nine compositions in total, were prepared and their characteristics evaluated. Sensors displayed cross-sensitivity to four studied toxins, i.e. response to several toxins together with low selectivity. High selectivity towards paralytic shellfish toxins was observed in the presence of inorganic cations with selectivity coefficients ranging from 0.04 to 0.001 for Na+ and K+ and 3.6*10-4 to 3.4*10-5 for Ca2+. Detection limits were in the range from 0.25 to 0.9 µmolL-1 for saxitoxin and decarbamoyl saxitoxin, and from 0.08 to 1.8 µmolL-1 for GTX5 and C1&C2, which allows toxin detection at the concentration levels corresponding to the legal limits. Characteristics of the developed sensors allow their use in the electronic tongue multisensor system for simultaneous quantification of paralytic shellfish toxins.


Assuntos
Técnicas Biossensoriais/métodos , Potenciometria/métodos , Saxitoxina/análogos & derivados , Saxitoxina/análise , Animais , Portugal , Reprodutibilidade dos Testes , Saxitoxina/química , Frutos do Mar/análise
19.
J Food Prot ; 81(2): 240-245, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29356586

RESUMO

Paralytic shellfish toxin (PST) producing microalgal blooms have a significant economic impact on the Southern Rock Lobster ( Jasus edwardsii) fishery in Tasmania, Australia. The regulatory level of 0.8 mg of saxitoxin (STX) eq/kg in place for bivalve shellfish fisheries is applied to lobster hepatopancreas during blooms of toxic algae, resulting in harvest closures and ongoing risk management implications for the fishery. This cooking study was undertaken to inform a human health risk assessment, in conjunction with studies on the uptake and elimination of PST in J. edwardsii. Live lobsters in tanks were contaminated through consumption of PST-containing mussels harvested during an Alexandrium tamarense Group 1 bloom event. This resulted in a mean lobster hepatopancreas level of 2.83 ± 0.84 mg of STX·2HCl eq/kg. Other edible tissues contained negligible concentrations of toxin. PST concentrations in all tissues did not significantly change after boiling or steaming, although the amount of hepatopancreas available for consumption did decrease significantly with both cooking methods, because the tissue became more dispersed, resulting in an overall reduction in the toxin exposure per hepatopancreas consumed. The toxin profile was dominated by STX; gonyautoxin 2, 3; N-sulfocarbamoyl-gonyautoxin 2, 3 (C1,2); and gonyautoxin 5. No significant changes to the toxin profile were observed after either of the cooking methods. Pâté, bisque, and soufflé prepared from the hepatopancreas of toxic lobsters contained negligible levels of PST in each serving; on average, a serving of pâté contained 0.01 mg of STX·2HCl eq, whereas a serving of bisque or soufflé contained <0.01 mg of STX·2HCl eq. The findings of this study will inform a risk assessment of PST in J. edwardsii to determine risk management options for this fishery in Australia.


Assuntos
Bivalves/parasitologia , Culinária , Palinuridae/química , Saxitoxina/análogos & derivados , Alimentos Marinhos , Animais , Austrália , Bivalves/química , Dinoflagelados , Saxitoxina/análise
20.
J AOAC Int ; 101(2): 480-489, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28797318

RESUMO

Detection of paralytic shellfish toxins (PSTs) in bivalve shellfish by analytical methods is complicated and costly, requiring specific expertise and equipment. Following extensive blooms of Alexandrium tamarense Group 1 in Tasmania, Australia, an investigation was made into commercially available screening test kits suitable for use with the toxin profiles found in affected bivalves. The qualitative Neogen rapid test kit, with a modified protocol to convert gonyautoxins GTX1&4 and GTX2&3 into neosaxitoxin and saxitoxin (STX), respectively, with higher cross-reactivities, was the best fit-for-purpose. This validation study of the test kit and the modified protocol was undertaken following AOAC INTERNATIONAL guidelines for the validation of qualitative binary chemistry methods. The validation used four different PST profiles representing natural profiles found in Australia and in Europe: two in a mussel matrix and two in an oyster matrix. The test kit was shown to have appropriate selectivity of the toxin analogs commonly found in bivalve shellfish. The matrix and probability of detection (POD) study showed that the rapid test kit used with the modified protocol was able to consistently detect PST at the bivalve regulatory level of 0.8 mg STX⋅2HCl eq/kg, with a POD estimated via the binomial logistic regression of 1.0 at 0.8 mg STX⋅2HCl eq/kg in all tested profiles in both matrixes. The POD at 0.4 mg STX⋅2HCl eq/kg was 0.75 and 0.46 for the two toxin profiles in an oyster matrix and 0.96 and 1.0 for the two toxin profiles in a mussel matrix. No significant differences in the PODs of the PSTs at the regulatory level were found between production lots of the test kits. The results suggest the method is suitable to undergo a collaborative validation study.


Assuntos
Toxinas Marinhas/análise , Saxitoxina/análogos & derivados , Animais , Cromatografia Líquida , Crassostrea/química , Dinoflagelados , Imunoensaio/métodos , Toxinas Marinhas/isolamento & purificação , Mytilus/química , Saxitoxina/análise , Saxitoxina/isolamento & purificação , Espectrometria de Massas em Tandem
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