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1
Hong, Haizheng. "Toxicological studies of paralytic shellfish toxins in mammalian systems /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202003%20HONG.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 101-111). Also available in electronic version. Access restricted to campus users.
2
Hold, Georgina Louise. "The role of bacteria in paralytic shellfish poisoning." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301622.
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Li, Pilong. "Radiobiosynthesis of paralytic shellfish toxins in the dinoflagellate alexandrium tamarense /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202002%20LI.
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4
Ho, Yam Tat. "The roles of bacteria in the production of paralytic shellfish toxins in two dinoflagellate cultures /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202003%20HO.
Full textAbstract:
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 118-130). Also available in electronic version. Access restricted to campus users.
5
Stranghetti, Bruno Garcia. "Monitoração toxinológica do pescado comercializado nos municípios de São Sebastião e Caraguatatuba, SP." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-06112007-180200/.
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As toxinas do envenenamento paralisante por moluscos (Paralytic Shellfish Poisoning PSP) são compostos naturais bioativos conhecidos devido ao consumo acidental de frutos do mar contaminados. Estas moléculas, das quais a mais potente é a saxitoxina (STX), são uma classe de alcalóides neurotóxicos que possuem diferentes análogos e diferentes toxicidades, e são produzidas por algumas cianobactérias e algumas espécies de dinoflagelados do gênero Alexandrium, Gymnodinium e Pyrodinium. As toxinas paralisantes são neurotoxinas solúveis em água que agem sobre células nervosas e musculares através do bloqueio dos canais de sódio dependentes de voltagem, desta maneira, impedindo a condução do sinal no neurônio o que leva a uma paralisia muscular. Em casos graves, pode ocorrer morte por insuficiência respiratória. O envenenamento diarréico por moluscos (Diarrhetic Shelfish Poisoning DSP) é caracterizado por problemas gastrointestinais com sintomas como diarréia, náusea, vômito, dor de cabeça, calafrios e dores abdominais. DSP é conseqüência do consumo de mariscos contaminados que ingeriram dinoflagelados do gênero Dynophysis e Prorocentrun através de sua alimentação por filtração da água. Contaminação de frutos do mar por toxinas PSP ou DSP coloca-se como sério problema para a indústria pesqueira e para a saúde pública. Neste estudo, estabeleceu-se um programa de monitoração para mexilhões (Perna perna) e para peixes (Sardinella brasiliensis, Anchoviella lepidentostole e Brevoortia aurea) coletados em peixarias e entrepostos de pesca no municípios de Caraguatatuba e São Sebastião, São Paulo. Os extratos para PSP foram preparados de duas maneiras: de acordo com a AOAC (Association of Official Analytical Chemists), através do aquecimento por 5 min de uma mistura de 100 g de tecidos homogeneizados com ácido acético 0,1 N; ou a partir da concentração de extratos etanólicos de músculo + pele dos peixes. Os bioensaios com camundongos para PSP consistem na injeção intraperitonial de 1 mL do extrato ácido em cada um dos três camundongos (~ 20 g). O animal é observado quanto aos sintomas clássicos de PSP e o tempo de morte é anotado e então a toxicidade é determinada (em mouse units, MU) pela tabela de Sommer. Para as toxinas causadoras de DSP, os extratos foram preparados pela extração com acetona do homogeneizado das glândulas digestivas, e a determinação da presença destas toxinas é feita através da injeção intraperitonial em camundongos. Nos bioensaios com os extratos preparados segundo o método da AOAC, não houve casos positivos. Para o bioensaio realizado com extratos etanólicos obtiveram-se resultados positivos para 77,8% dos extratos testados. A média de MU de todas as amostras, neste caso, foi de 0,147 MU/g. Nos bioensaios para DSP, três amostras resultaram em sinais que evidenciam a presença destas toxinas, pois os camundongos injetados apresentaram quadro diarréico. Os extratos etanólicos, com positividade para as toxinas de PSP, foram fracionados usando-se colunas Sep-Pak C18. A primeira eluição, com ácido acético 0,1 M, foi analisada usando-se o método de préderivatização e cromatografia líquida de alta eficiência com detecção de fluorescência. As analises em CLAE indicaram a presença de compostos semelhantes às toxinas paralisantes de PSP, confirmando os bioensaios. Portanto, pela primeira vez no Brasil demonstrou-se que as espécies S. brasiliensis, A. lepidentostole e B. aurea são portadoras de toxinas paralisantes, semelhantes às PSP, em pequenas concentrações e que um programa de monitoração é necessário em nosso país para verificação da presença dessas toxinas em organismos que são usados como alimento pela população.The Paralytic Shellfish Poisoning (PSP) toxins are well-known natural bioactive compounds due to their accidental consumption in contaminated seafood. These molecules, of which the most potent representative is saxitoxin (STX), are a class of neurotoxic alkaloids, having different isoforms and varied toxicities, that are produced by some cyanobacteria and some species of dinoflagellates from the genus Alexandrium, Gymnodinium and Pyrodinium. PSP toxins are water-soluble neurotoxins that act on nerve and muscle cells by blocking sodium channels voltage-dependent, thus preventing the conductance of neuron signal leading to muscular paralysis. In severe cases, death may result due to respiratory failure. Diarrhetic Shellfish Poisoning (DSP) is a gastrointestinal illness with symptoms such as diarrhea, nausea, vomiting, headache, chills and moderate to severe abdominal pain. DSP is usually a consequence of consuming contaminated shellfish that have ingested dinoflagellates of the genera Dinophysis and Prorocentrun through their filter feeding activities. Contamination of seafood by PSP and DSP toxins has posed serious problems to the fisheries industry as well to public health. In this study, was stabilized a monitoring program to shellfish (Perna perna) and finfish (Sardinella brasiliensis, Anchoviella lepidentostole and Brevoortia aurea) collected in fish markets in Caraguatatuba and São Sebastião cities, São Paulo state. The extracts for PSP were prepared by two ways: according to AOAC (Association of Official Analytical Chemists), through the heating for 5 min of blend of 100 g of well mixed sample with 0.1 N HCl; or through of the concentration of ethanolic extracts from finfishs muscle + skin. The PSP mouse bioassay for PSP toxins involves intraperitonial injection (i.p.) of 1 mL of the acid extract into each of three mice (~ 20 g). The mice were observed for classical PSP symptoms and the time to mouse death was recorded and the toxicity was determinate (in mouse units, MU) from the Sommers table. To DSP toxins, the extracts was prepared trough the extraction of digestive glands with acetone, and i.p injection in mice was used to determine the presence of theses toxins. In the mouse bioassay for the extracts prepared by AOAC method no positive results was obtained. For the mouse bioassay with ehtanolic extracts was obtained positive results to 77.8 % of the tested extracts. The media of MU of all samples, in this case, was 0,147 MU/g. To the mouse bioassay for the DSP toxins, three samples gives evidence of presence of the diarrhetic toxins, because the mice showed signal like diarrhea. The ethanolic extracts, that was positive to the PSP toxins, was fractionated by a Sep-Pak C18 cartridge. The first elution, with 0.1 M acetic acid, was analyzed by using prechromatographic oxidation and liquid chromatography with fluorescence detection. The HPLC analysis indicated the presence of the PSP toxins, confirming the bioassays. Therefore, in the first time in Brazil was demonstrated that the species S. brasiliensis, A. lepidentostole and B. aurea are carriers of toxins like PSP in little concentrations and that a monitoring program is necessary in our country to verify the presence of these toxins in organisms that are used as food by the population.
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Harper, Terry L. "Improved methods of detection for the difficult to identify marine toxin, Okadaic acid /." Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/harpert/terryharper.pdf.
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Contreras, Garces Andrea Maud. "Physiological Effects and Biotransformation of Paralytic Shellfish Toxins in New Zealand Marine Bivalves." Thesis, University of Canterbury. School of Biological Sciences, 2010. http://hdl.handle.net/10092/5181.
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Although there are no authenticated records of human illness due to PSP in New Zealand, nationwide phytoplankton and shellfish toxicity monitoring programmes have revealed that the incidence of PSP contamination and the occurrence of the toxic Alexandrium species are more common than previously realised (Mackenzie et al., 2004). A full understanding of the mechanism of uptake, accumulation and toxin dynamics of bivalves feeding on toxic algae is fundamental for improving future regulations in the shellfish toxicity monitoring program across the country. This thesis examines the effects of toxic dinoflagellates and PSP toxins on the physiology and behaviour of bivalve molluscs. This focus arose because these aspects have not been widely studied before in New Zealand.
The basic hypothesis tested was that bivalve molluscs differ in their ability to metabolise PSP toxins produced by Alexandrium tamarense and are able to transform toxins and may have special mechanisms to avoid toxin uptake. To test this hypothesis, different physiological/behavioural experiments and quantification of PSP toxins in bivalves tissues were carried out on mussels (Perna canaliculus), clams (Paphies donacina and Dosinia anus), scallops (Pecten novaezelandiae) and oysters (Ostrea chilensis) from the South Island of New Zealand.
Measurements of clearance rate were used to test the sensitivity of the bivalves to PSP toxins. Other studies that involved intoxication and detoxification periods were carried out on three species of bivalves (P. canaliculus, P. donacina, P. novaezelandiae), using physiological responses (clearance and excretion rate) and analysis of PSP toxins in the tissues over these periods. Complementary experiments that investigated other responses in bivalves fed with the toxic cells were also carried out. These included byssus production, and the presence of toxic cells in the faeces of mussels, the siphon activity and burrowing depth in clams and the oxygen consumption in scallops.
The most resistant species to PSP toxins were the mussel, Perna canaliculus and the clam, Dosinia anus. Both species fed actively on toxic dinoflagellates and accumulated toxins. The intoxication and detoxication rate of the mussel was faster than the other species of bivalve studied (P. donacina and P. novaezelandiae) which confirm mussels as a good sentinel species for early warning of toxic algal blooms.
The clearance rate of the clam, Paphies donacina decreased when fed on Alexandrium species but the effect of the PSP toxins on this physiological response was not confirmed. Over the detoxification period of 8 days, this clam did not detoxify which suggests that its ability to retain high level of toxins for an extensive period may be critical for public health management.
The scallop, Pecten novaezelandiae was clearly the most sensitive species to the PSP toxins and the clearance rate was significantly lower in the presence of the toxic dinoflagellate A. tamarense. Although the clearance rate was low, the scallops still fed on the toxic dinoflagellate and accumulated PSP toxins in the tissues. The scallops detoxified slowly which would affect the market for this bivalve in the presence of a toxic algal bloom. This bivalve would retain PSP toxins for longer period of time than other species such as mussels.
The oyster, Ostrea chilensis, had erratic clearance rate and did not respond clearly to any of the variables tested over the time. Oysters accumulated more toxins than the sensitive species, but they had been exposed to two more days of feeding with A. tamarense; therefore this species may actually have a similar intoxication responses to P. novaezalandiae and P. donacina.
The results from this thesis suggest further directions for the aquaculture sector and ongoing research in this field, which in future will lead to a better selection of suitable species for culture as well as species for monitoring of PSP toxins. In the future, research that integrates field and controlled laboratory studies will expand to other species of interest and a more complete record will in time be available in order to manage more efficiently the negative effects that harmful algal blooms may have in New Zealand.
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Burgess, Vanessa Anne, and n/a. "Toxicology Investigations With The Pectenotoxin-2 Seco Acids." Griffith University. School of Public Health, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030905.090222.
Full textAbstract:
Pectenotoxins (PTXs) are a group of large cyclic polyether compounds associated with diarrhetic shellfish poisoning (DSP) as they are often found in combination with other DSPs such as okadaic acid (OA) and dinophysis toxins (DTXs) in shellfish. Although classified and regulated with the DSPs, there is debate over whether these toxins should be classified with DSP toxins. To date, ten different analogues of PTXs have been identified from shellfish and algae, and of these, the pectenotoxin-2 seco acids (PTX2-SAs) are of particular interest as they have previously been implicated in a shellfish poisoning incident in Australia, but relatively little was known of their toxicology. One such incident occurred in December 1997, when approximately 200 people were reported with severe diarrhoetic shellfish poisoning in Northern New South Wales (NSW). Analysis of the shellfish associated with this incident revealed relatively high PTX2-SA concentrations (approx. 300 micrograms/kg shellfish meat), with only trace amounts of pectenotoxin-2 (PTX2) and OA. Following this incident, PTX2-SAs were considered a health threat and guidelines were implemented in the absence of toxicological data, which has caused a great economic burden to shellfish industries around the globe, in particular to Australia, New Zealand and Ireland. Such regulation created in the absence of scientific data demonstrated the need to determine the toxicology of PTX2-SAs in commercial shellfish. Thus a comprehensive study on the toxicology and possible health implications of the PTX2-SAs in Australian shellfish was conducted. PTX2-SAs were isolated in different batches from shellfish (pipis, oysters and mussels) and from algal bloom samples of Dinophysis caudata. Toxin extraction was conducted with several purification stages and chemical analysis was performed with high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). The chemical stability of the PTX2-SAs was investigated to ensure consistency of doses between toxicology experiments. Acute dosing studies with mice were then performed and included toxicopathology investigations with light microscopy and electron microscopy, in addition to toxin distribution studies and investigation of in vivo lipid peroxidation. In vitro studies with HepG2 cells included cytotoxicity assays, cell cycle investigations using flow cytometry and gene expression profiling of cells exposed to PTX2-SAs employing cDNA microarray technology. Acute pathology studies demonstrated that the PTX2-SAs do not cause the characteristic symptoms or lesions associated with DSP toxins. No diarrhoea was observed at any dose level in mice and no deaths occurred up to the maximum dosing level of 1.6mg/kg PTX2-SA. Only one batch of PTX2-SA extract produced toxic lesions characteristic of a DSP toxin (batch 1-pilot study) but after follow up studies, it was determined that this first batch of shellfish most likely contained an additional unidentified shellfish toxin or contaminant that co-extracted with PTX2-SAs during toxin isolation and purification procedures. This finding highlighted the importance of supporting the inclusion of the mice bioassay in procedures for shellfish toxin testing to enable detection of new toxins, and also highlighted the importance of toxin purification for toxicology studies. A significant rise in malondialdehyde excretion was observed within 24 hours of dosing mice, indicating that the PTX2-SAs may cause damage by lipid peroxidation in vivo. In vitro studies showed HepG2 cells to have cell cycle and gene expression changes within 24 hours of a dose of 800ng/mL PTX2-SAs. Cell cycle arrest was observed at the G2/M checkpoint and gene expression changes included alterations in genes involved in cell cycle control, lipid metabolism and transport, lipid genesis and trace metal transport. Many genes involved in DNA repair processes were moderated at the 24 hour point, but as no apoptosis was observed up to 72 hours post dosing it is a promising indication that any DNA damage that may have been caused by the administration of PTX2-SAs was not lethal, and was able to be repaired. In light of the information provided by toxicology investigations in this PhD, with particular reference to evidence of in vivo lipid peroxidation by raised levels of MDA in mouse urine, and changes in cell cycle distribution and gene expression in a cultured human cell line, it is concluded that there is potential for these toxins to induce biological changes in mammalian cells in vivo and in vitro, and hence potential for PTX2-SAs to cause health effects in humans. During the course of this three-year study, developments in techniques for shellfish toxin identification within our laboratories have revealed that the shellfish responsible for the 1997 NSW poisoning incident contained significant concentrations of okadaic acid acyl esters that were not detected at the time of the NSW incident. Although reportedly less toxic than okadaic acid itself, the OA ester concentrations present may have been sufficient to cause the observed symptoms. It is also theorized that these esters could be hydrolyzed in the human gastro-intestinal tract to release okadaic acid. In the light of this new evidence and with no pathology lesions or symptoms of diarrhoea being observed in PTX2-SA dosing studies with mice, we now believe these OA acyl esters to be the causative agent in the 1997 NSW DSP incident and not the PTX2-SAs. Nothing is currently known of the chronic toxicology of PTX2-SAs and thus their potential implications to public health in the long term cannot determined. The toxicology investigations in this thesis were acute studies, and it has not been established if the observed changes could be repaired or returned within normal limits without the manifestation of illness or disease occurring. Utilizing the acute toxicology information in this thesis, a health risk assessment for consumption of PTX2-SA contaminated shellfish was performed. This risk assessment, employing numerous safety factors essential for an incomplete data set, produced guideline values that are lower than the current recommend concentrations. To date, there has been no solid evidence that PTX2-SAs cause illness in humans all documented incidents involving the PTX2-SAs have also included other DSP contaminants that are known to cause human illness. Pathology has not unequivocally been demonstrated in animal studies and thus, in consideration of the epidemiological evidence, PTX2-SAs cannot be considered as high a risk to public health as was previously thought. For the reasons discussed above, and weighing up risk-benefit considerations of the economic burden the current guideline values are causing to shellfish industries around the globe, it is recommended that levels of PTX2-SAs be monitored in recognition of the precautionary principle, but no longer regulated as tightly with other DSPs until such a time that toxicological or epidemiological evidence can prove that the PTX2-SAs are a DSP and are a more considerable threat to human health than has been indicated by toxicology studies in this thesis. This study has produced a substantial amount of acute toxicology data and has provided a good basis for future chronic toxicology investigations with the PTX2-SAs for regulatory purposes.
9
Burgess, Vanessa Anne. "Toxicology Investigations With The Pectenotoxin-2 Seco Acids." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/365382.
Full textAbstract:
Pectenotoxins (PTXs) are a group of large cyclic polyether compounds associated with diarrhetic shellfish poisoning (DSP) as they are often found in combination with other DSPs such as okadaic acid (OA) and dinophysis toxins (DTXs) in shellfish. Although classified and regulated with the DSPs, there is debate over whether these toxins should be classified with DSP toxins. To date, ten different analogues of PTXs have been identified from shellfish and algae, and of these, the pectenotoxin-2 seco acids (PTX2-SAs) are of particular interest as they have previously been implicated in a shellfish poisoning incident in Australia, but relatively little was known of their toxicology. One such incident occurred in December 1997, when approximately 200 people were reported with severe diarrhoetic shellfish poisoning in Northern New South Wales (NSW). Analysis of the shellfish associated with this incident revealed relatively high PTX2-SA concentrations (approx. 300 micrograms/kg shellfish meat), with only trace amounts of pectenotoxin-2 (PTX2) and OA. Following this incident, PTX2-SAs were considered a health threat and guidelines were implemented in the absence of toxicological data, which has caused a great economic burden to shellfish industries around the globe, in particular to Australia, New Zealand and Ireland. Such regulation created in the absence of scientific data demonstrated the need to determine the toxicology of PTX2-SAs in commercial shellfish. Thus a comprehensive study on the toxicology and possible health implications of the PTX2-SAs in Australian shellfish was conducted. PTX2-SAs were isolated in different batches from shellfish (pipis, oysters and mussels) and from algal bloom samples of Dinophysis caudata. Toxin extraction was conducted with several purification stages and chemical analysis was performed with high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). The chemical stability of the PTX2-SAs was investigated to ensure consistency of doses between toxicology experiments. Acute dosing studies with mice were then performed and included toxicopathology investigations with light microscopy and electron microscopy, in addition to toxin distribution studies and investigation of in vivo lipid peroxidation. In vitro studies with HepG2 cells included cytotoxicity assays, cell cycle investigations using flow cytometry and gene expression profiling of cells exposed to PTX2-SAs employing cDNA microarray technology. Acute pathology studies demonstrated that the PTX2-SAs do not cause the characteristic symptoms or lesions associated with DSP toxins. No diarrhoea was observed at any dose level in mice and no deaths occurred up to the maximum dosing level of 1.6mg/kg PTX2-SA. Only one batch of PTX2-SA extract produced toxic lesions characteristic of a DSP toxin (batch 1-pilot study) but after follow up studies, it was determined that this first batch of shellfish most likely contained an additional unidentified shellfish toxin or contaminant that co-extracted with PTX2-SAs during toxin isolation and purification procedures. This finding highlighted the importance of supporting the inclusion of the mice bioassay in procedures for shellfish toxin testing to enable detection of new toxins, and also highlighted the importance of toxin purification for toxicology studies. A significant rise in malondialdehyde excretion was observed within 24 hours of dosing mice, indicating that the PTX2-SAs may cause damage by lipid peroxidation in vivo. In vitro studies showed HepG2 cells to have cell cycle and gene expression changes within 24 hours of a dose of 800ng/mL PTX2-SAs. Cell cycle arrest was observed at the G2/M checkpoint and gene expression changes included alterations in genes involved in cell cycle control, lipid metabolism and transport, lipid genesis and trace metal transport. Many genes involved in DNA repair processes were moderated at the 24 hour point, but as no apoptosis was observed up to 72 hours post dosing it is a promising indication that any DNA damage that may have been caused by the administration of PTX2-SAs was not lethal, and was able to be repaired. In light of the information provided by toxicology investigations in this PhD, with particular reference to evidence of in vivo lipid peroxidation by raised levels of MDA in mouse urine, and changes in cell cycle distribution and gene expression in a cultured human cell line, it is concluded that there is potential for these toxins to induce biological changes in mammalian cells in vivo and in vitro, and hence potential for PTX2-SAs to cause health effects in humans. During the course of this three-year study, developments in techniques for shellfish toxin identification within our laboratories have revealed that the shellfish responsible for the 1997 NSW poisoning incident contained significant concentrations of okadaic acid acyl esters that were not detected at the time of the NSW incident. Although reportedly less toxic than okadaic acid itself, the OA ester concentrations present may have been sufficient to cause the observed symptoms. It is also theorized that these esters could be hydrolyzed in the human gastro-intestinal tract to release okadaic acid. In the light of this new evidence and with no pathology lesions or symptoms of diarrhoea being observed in PTX2-SA dosing studies with mice, we now believe these OA acyl esters to be the causative agent in the 1997 NSW DSP incident and not the PTX2-SAs. Nothing is currently known of the chronic toxicology of PTX2-SAs and thus their potential implications to public health in the long term cannot determined. The toxicology investigations in this thesis were acute studies, and it has not been established if the observed changes could be repaired or returned within normal limits without the manifestation of illness or disease occurring. Utilizing the acute toxicology information in this thesis, a health risk assessment for consumption of PTX2-SA contaminated shellfish was performed. This risk assessment, employing numerous safety factors essential for an incomplete data set, produced guideline values that are lower than the current recommend concentrations. To date, there has been no solid evidence that PTX2-SAs cause illness in humans – all documented incidents involving the PTX2-SAs have also included other DSP contaminants that are known to cause human illness. Pathology has not unequivocally been demonstrated in animal studies and thus, in consideration of the epidemiological evidence, PTX2-SAs cannot be considered as high a risk to public health as was previously thought. For the reasons discussed above, and weighing up risk-benefit considerations of the economic burden the current guideline values are causing to shellfish industries around the globe, it is recommended that levels of PTX2-SAs be monitored in recognition of the precautionary principle, but no longer regulated as tightly with other DSPs until such a time that toxicological or epidemiological evidence can prove that the PTX2-SAs are a DSP and are a more considerable threat to human health than has been indicated by toxicology studies in this thesis. This study has produced a substantial amount of acute toxicology data and has provided a good basis for future chronic toxicology investigations with the PTX2-SAs for regulatory purposes.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
Faculty of Health Sciences
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Barber, Kathleen Gladys. "Response of the shore crabs Hemigrapsus oregonesis and Hemigrapsus nudus to paralytic shellfish toxins." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27797.
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The following research deals with the response of the small shore crabs, Hemigrapsus oreqonesis and Hemigrapsus nudus to paralytic shellfish toxins (PST). These shore crabs were shown to develop a remarkable seasonal resistance to administered saxitoxin (STX). No similar change in sensitivity was found after administration of tetrodotoxin (TTX), another marine neurotoxin with similar actions to the PST. Resistance to STX in the small shore crabs was linked to the presence of PST in the viscera, and this in turn was related to the presence of toxic dinoflagellate blooms in the area. Furthermore, this research provides, for the first time, evidence of a protein component (MW 145,000 daltons) which appears to be associated with acquired resistance to PST in the shore crab. In addition, this protein component was shown to appear in sensitive crab extracts after the administration of low doses of saxitoxin and tetrodotoxin in vivo.Land and Food Systems, Faculty of
Graduate
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Bauder, Andrew G. "Dynamics of diarrhetic shellfish toxins from the dinoflagellate Prorocentrum lima in the bay scallop Argopecten irradians." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq24799.pdf.
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Wong, Barbara Carleton University Dissertation Chemistry. "Novel approaches to the oxidation of paralytic shellfish poisoning toxins for analysis by high-performance liquid chromatography." Ottawa, 1996.
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Percy, Linda Ann. "An investigation of the phytoplankton of the Fal Estuary, UK and the relationship between the occurrence of potentially toxic species and associated algal toxins in shellfish." Thesis, University of Westminster, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434277.
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Boullot, Floriane. "Implication des canaux sodium voltage-dépendant dans la réponse aux toxines chez Crassostrea gigas : le cas des phycotoxines paralysantes." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0014/document.
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Lors des efflorescences de micro-algues productrices de toxines paralysantes (PST), les bivalves filtreurs peuvent bioaccumuler une grande quantité de toxines et devenir à leur tour toxiques, notamment pour l’homme. La quantité de toxines PST accumulée d’un individu à l’autre s’avère être très variable au sein même d’une population de bivalves. Ainsi, dans nos conditions expérimentales, la quantité de PST accumulées par des huîtres creuses, Crassostrea gigas, d’un même lot, exposées au dinoflagellé toxique Alexandrium minutum, variait d’un facteur 450. L’origine de cette variabilité est inconnue jusqu’alors mais l’une des hypothèses pour l’expliquer serait l’existence de plusieurs formes de canaux sodium voltage-dépendant (NaV), cible des PST, qui confèreraient aux bivalves des sensibilités différentes aux PST. L’objectif principal de cette thèse était de comprendre s’il existe une sensibilité individuelle aux PST différente entre les huîtres et si cette variabilité pouvait être due à des formes différentes de NaV.Une première partie a permis de caractériser le NaV chez C. gigas par une approche de biologie moléculaire. Deux gènes NaV ont été mis en évidence chez C. gigas : CgNaV1, codant un canal sodium et CgNaV2 codant un canal potentiellement sélectif du sodium et du calcium. L’épissage alternatif de CgNaV1 produits trois variants (A, B et C) avec des profils d’expression différents : au niveau des jonctions neuromusculaires pour CgNaV1A, dans les cellules nerveuses pour CgNaV1B et dans les deux pour CgNaV1C. L'acide aminé Q, observé dans le site de liaison aux PST (domaine II) de la séquence CgNaV1 pour les 3 variants et chez tous les individus des 4 populations étudiées, pourrait conférer aux huîtres une certaine résistance aux PST. Ainsi, les variants issus du génotypage/épissage de CgNaV1 ne seraient donc pas le point déterminant du niveau de bioaccumulation des huîtres.Une deuxième partie a permis d’étudier la sensibilité aux PST des nerfs de l’huître creuse C.gigas en relation avec l’accumulation de PST par une approche d’électrophysiologie. La sensibilité à la STX des nerfs cérébroviscéraux d'huîtres a été évaluée en étudiant leur potentiel d'action (CNAP).Il a été montré que les nerfs de C. gigas possédaient une sensibilité à la STX de l’ordre du micromolaire, ce qui leur confère une sensibilité intermédiaire parmi les bivalves. Cette sensibilité des nerfs peut varier selon la période à laquelle les huîtres ont été prélevées et potentiellement selon leur condition physiologique. Une pré-exposition des huîtres à A. minutum semble augmenter la résistance des nerfs à la STX. Cependant, aucune corrélation significative n'a été observée entre la sensibilité nerveuse à la STX et la charge en PST dans la glande digestive des huîtres.Il apparait donc que la variabilité de l’accumulation des PST par les huîtres résulterait plutôt d’une plasticité physiologique, en terme de filtration, d’ingestion et d’assimilation, que d’une sensibilité différentielle des NaVDuring bloom of microalgae producing paralytic shellfish toxins (PST), filtering bivalves can bio-accumulate a large quantity of toxins and become toxic for human consumption. The amount of accumulated PST can greatly vary from one individual to another within a bivalve population. Indeed, under our experimental conditions, the amount of accumulated PST by Pacific oysters, Crassostrea gigas, exposed to the toxic dinoflagellate Alexandrium minutum, varied by a factor of 450. To explain such variability we hypothesized the existence of several forms of voltage-gated sodium channel (NaV), target of the PST, resulting in different sensitivities to PST. The main objective of this thesis was to understand whether there are relationships between nerve sensitivity to PST, the different forms of NaV and the amount of accumulated PST.The NaV was first characterized in C. gigas by a molecular biology approach. Two NaV genes were reported in C. gigas: CgNaV1, encoding a sodium channel and CgNaV2 encoding a channel potentially selective for sodium and calcium. Alternative splicing of CgNaV1 produced three variants (A, B and C) with different expression profiles: at the neuromuscular junctions for CgNaV1A, in the nerve cells for CgNaV1B and in both for CgNaV1C. The amino acid Q observed in the binding site of PST (domain II), of the sequence CgNaV1 for the 3 variants and in all individuals from the 4 studied populations possibly provide some PST resistance to oysters. Thus, the variants resulting from the genotyping/splicing of CgNaV1 would not therefore be the determining factor of the level of bioaccumulation in oysters.A second part allowed studying the nerve sensitivity to PST of C. gigas oyster in relation to the accumulation of PST by an electrophysiology approach. The sensitivity to saxitoxin (STX, a PST) of the cerebro-visceral nerves from oysters was assessed by studying their action potential (CNAP). C.gigas nerves have been shown to have sensitivity to STX of the micromolar range, which gives them intermediate sensitivity among bivalves. This nerve sensitivity may vary depending on the period at which the oysters were collected and potentially according to their physiological condition. A preexposure of oysters to A. minutum appears to increase nerve resistance to STX. However, there was no significant correlation between STX nerve sensitivity and PST content in the oyster digestive gland.Overall, it appears that the variability of the PST accumulation by oysters would result rather from a physiological plasticity, in terms of filtration, ingestion and assimilation, than from a differential sensitivity of the NaV
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Adu-Ampratwum, Daniel Dr. "Synthesis of the ABCD- and EFGHI-Domains of Azaspiracid-3." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461310628.
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Castrec, Justine. "Impacts des efflorescences du dinoflagellé toxique Alexandrium minutum sur la reproduction et le développement de l'huître Crassostrea gigas." Thesis, Brest, 2018. http://www.theses.fr/2018BRES0080.
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Les dernières décennies ont été marquées par l’intensification et l’expansion des efflorescences de micro-algues toxiques (HAB). Connues pour perturber les écosystèmes côtiers et pour leur toxicité sur les organismes marins, les HAB sont suspectées d’être à l’origine de défauts de recrutement de bivalves. Cette thèse avait pour objectif d’étudier les conséquences des efflorescences du dinoflagellé toxique Alexandrium minutum, producteur de toxines paralysantes (PST) et des composés bioactifs extracellulaires (BEC), sur la reproduction, le développement et le recrutement de l’huître Crassostrea gigas, une espèce à l’importance économique majeure. Les gamètes libres et les jeunes stades de développement se révèlent être les plus sensibles, en particulier aux BEC produits par A. minutum qui inhibent la fécondation et l’embryogenèse. A. minutum modifie le comportement des larves véligères, provoque une diminution de leur filtration, de leur croissance et du taux de fixation. Une exposition des adultes, pendant la gamétogenèse, affecte le développement des descendants, traduisant des altérations du contenu gamétique et/ou un transfert vertical des PST. Les modalités d’action des PST et des BEC devront être précisées. Nos expérimentations, réalisées à des concentrations de micro-algues rencontrées dans l’environnement, suggèrent que des efflorescences récurrentes d’A. minutum lors des périodes de reproduction et de développement larvaire pourraient, sur le long terme, affecter la structure des populations naturelles et cultivées de C. gigasRecent decades have witnessed the intensification and spread of harmful algal blooms (HAB). HAB are known to disrupt coastal ecosystems and to be toxic for marine organisms. These phenomena are also suspected to be responsible for recruitment failures of bivalves. The aim of this PhD was to study the consequences of blooms of toxic dinoflagellate Alexandrium minutum on the reproduction, development and recruitment of the oyster Crassostrea gigas, a species of major economic importance. A. minutum is known to produce paralytic shellfish toxins (PST) and bioactive extracellular compounds (BEC). Gametes and early life stages were the most sensitive, particularly to the bioactive extracellular compounds (BEC) produced by A. minutum, which inhibited fertilization and embryogenesis. A. minutum modified the behaviour of veliger larvae, decreased their filtration, growth and settlement. Exposure of adult oysters during gametogenesis affected the development of offspring, reflecting alterations in gamete content and/or vertical transfer of PST. Mode of action of PST and BEC are to further investigate. These oyster exposures, conducted at environmentally relevant concentrations of microalgae, suggest that recurrent blooms of A. minutum during oyster spawning and larval development could have long-term consequences on the structure of wild and cultured populations of C. gigas
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Allen, Sara E. "Florida Red Tides: Public Perceptions of Risk." [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002267.
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Selander, Erik. "Chemical ecology of paralytic shellfish toxin producing dinoflagellates /." Göteborg : Fiskebäckskil : Dept. of Marine Ecology, Göteborg University, Kristineberg ; Kristineberg Marine Research Station, 2007. http://www.loc.gov/catdir/toc/fy0804/2007440828.html.
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Semones, Molly C. "Regulation and Testing for Marine Biotoxins." Ohio University Honors Tutorial College / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1283867789.
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John, E. H. "Growth dynamics and physiology of paralytic shellfish toxin producing dinoflagellates." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637432.
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Studies on the growth dynamics and physiology of the paralytic shellfish toxin producing dinoflagellates Alexandrium fundyense, A. minutum and Gymnodinium catenatum were conduced under a number of different nutrient regimes, light, temperature and salinity levels. G. catenatum was very slow to respond to N-refeeding, with relatively low internal amino acid concentrations, a low glutamine:glutamate ratio, and a stable toxin content, showing little variation with N- and P-limitation or with decreased salinity. In contrast Alexandrium sp. respond to N-refeeding with an increased internal amino acid pool, an increased glutamine: glutamate ratio, especially with ammonium as a N-source, and an increased toxin content. P-limitation in A. fundyense leads to a significant increase in the toxin content but only when cells are also N-limited. Sub-optimal temperature and light levels lead to decreased growth rates: low temperature results in larger cells and an increased toxin content in A. fundyense, whilst the effect of low light on A. minutum cells varies with the N-source available. The N-uptake kinetics of G. catenatum revealed that the maximum uptake rates (Vmas) and half-saturation constants (Ks) for transport were higher for ammonium when compared with nitrate. In A. funyense values of Ks were similar at 1 μM for both nitrate and ammonium whilst Vmax for the latter was up to 5-times greater. A. fundyense was shown to be able to utilize organic-N in the form of dissolved free amino acids. Maximum uptake rates of 0.85 pmol cell-1 h-1 occurred during exponential growth and differed from the uptake capabilities of other phytoplankton in that uptake was not enhanced by N- or C-stress. A preliminary model is presented and is capable of simulating the relationship between N-refeeding and P-limitation and cellular toxin content in Alexandrium sp.
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Chiu, Ellen, and 招雅莉. "Proteomic and physiological studies of paralytic shellfish toxin producing dinoflagellates: Alexandriumtamarense and Gymnodinium catenatum." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38827761.
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Chiu, Ellen. "Proteomic and physiological studies of paralytic shellfish toxin producing dinoflagellates Alexandrium tamarense and Gymnodinium catenatum /." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38827761.
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Pate, Susan Elizabeth. "Impacts of the toxic dinoflagellate Alexadrium monilatum on three ecologically important shellfish species." NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-03062006-182116/.
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Little is known about interactions between shellfish and Alexandrium monilatum (Howell) Balech, a toxigenic dinoflagellate that forms blooms mostly in the Gulf of Mexico. Toxic A. monilatum produces endotoxins with hemolytic and neurotoxic properties, and has been linked to major fish and invertebrate kills. The responses of three ecologically important shellfish species to A. monilatum (toxic strain AMO3) were experimentally assessed. In the first set of experiments, grazing studies were conducted with adult and juvenile eastern oysters (Crassostrea virginica Gmelin), northern quahogs (Mercenaria mercenaria Linnaeus), and green mussels (Perna viridis Linnaeus), which inhabit areas where A. monilatum blooms occur. Clearance rates of each shellfish species were depressed when exposed to toxic A. monilatum (bloom density of ~550 cells ml-1) alone or with nontoxic Instant Algae® Pavlova, in comparison to clearance rates of control animals fed benign cryptophyte algae. There was also a reduction in the clearance rate of adult and juvenile C. virginica and P. viridis, as well as juvenile M. mercenaria exposed to A. monilatum, in comparison to control animals that were exposed to a nontoxic strain of a dinoflagellate of similar size, Alexandrium tamarense (clone CCMP115). Exposure to toxic A. monilatum significantly decreased shellfish valve gape in adult P. viridis and C. virginica. Intact A. monilatum cells were found within shellfish feces, but A. monilatum cells did not divide following passage through the gut. In the second set of experiments, survival of larval M. mercenaria and C. virginica was tested when the larvae were exposed to A. monilatum as intact cells, cells held in dialysis tubing, or sonicated cells. Survival of larvae was significantly less when exposed to sonicated A. monilatum, in comparison to survival of control larvae that were tested with nontoxic A. tamarense. Overall, these data indicate that A. monilatum blooms can adversely affect survival of some shellfish species by reducing clearance rate and valve gape, affecting food intake, and inducing larval mortality.
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Windust, Anthony James. "The physiological ecology of diarrhetic shellfish poisoning (DSP) toxin production by the dinoflagellate Exuviaella lima (Ehr.) Bütschli." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ36593.pdf.
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蕭嘉裕 and Ka Yu Gavin Siu. "An investigation of a toxic red tide dinoflagellate alexandrium catenella: physiology, occurrence andtoxicity." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31235293.
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Fartouna-Bellakhal, Mouna. "Distribution spatiale des kystes de résistance des Dinoflagellés au niveau du sédiment superficiel de la lagune de Bizerte : cas de l’espèce invasive Alexandrium pacificum R.W. Litaker, 2014." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2081/document.
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Les rejets des eaux de ballast dans le port de Bizerte et les fermes conchylicoles installées au niveau de la lagune de Bizerte peuvent constituer des sources potentielles ayant un impact sur l’introduction des espèces de Dinoflagellés nuisibles, en particulier celles qui sont potentiellement toxiques telles que A. pacificum, A.pseudogonyaulax, A.minutum, A. affine et Polysphaeridium zoharyi, sans pour autant négliger le rôle des courants dans la distribution des kystes. L’étude du trafic maritime sur les 7 années précédant notre prospection a révélé que 14 % de la flotte qui accoste au port de Bizerte est en provenance de la voie maritime d’origine Pacifique. Afin d’identifier les espèces de Dinoflagellés produisant des kystes à l’origine des efflorescences potentiellement toxiques, un échantillonnage à grande échelle spatiale au niveau des sédiments superficiels a été effectué pour relever les densités des kystes en fonction des caractéristiques sédimentaires à savoir la teneur en eau, la matière organique, la granulométrie, l’abondance des formes végétatives ainsi que les facteurs environnementaux. Cette étude a permis l’identification de 48 morphotypes de kystes de Dinoflagellés, principalement dominés par Brigantidinium simplex, Votadinum spinosum, Alexandrium pacificum, Alexandrium pseudogonyaulax, et Lingulodinum machaerophorum. La densité des kystes a varié de 1276 à 20126 kystes g-1 sédiment sec. Des différences significatives portant sur la distribution des kystes ont été enregistrées, ce qui nous a permis de faire la distinction de deux zones dans la lagune de Bizerte. Un intérêt particulier a été porté au complexe Alexandrium tamarense dont fait partie l’espèce A. pacificum connue pour être à l’origine des efflorescences nuisibles (HABs). En outre, l’examen morphologique et le ribotypage des formes végétatives d’A. pacificum en provenance de cultures microalgales obtenues à partir de l’extraction, l’isolement des kystes de résistance en provenance du sédiment, et leur germination ont été réalisés pour l’obtention d’une culture cellulaire monospécifique ABZ1 qui se caractérise par un taux de croissance de µ= 0.33j-1 et un temps de génération T=2.1j. Le profil toxinique obtenu à partir d’un extrait de culture ABZ1, en phase exponentielle a révélé la présence de N-sulfocarbamoyl toxine C1 (9.82 pg toxin cell_1), la GTX6 (3.26 pg toxine cell_1) et la carbamoyl toxine Neo-STX (0.38 pg toxin cell_1), représentant 2,8% du total des toxines de cette souche. Une corrélation entre l’abondance des kystes d’Alexandrium pacificum et le pourcentage en eau ainsi que la matière organique a été relevée. Par ailleurs, la fraction sédimentaire <63µm s’est avérée potentiellement favorable à l’initiation des efflorescences du dinoflagellé Alexandrium pacificum au niveau de la lagune de Bizerte. Une différence significative dans le schéma de la distribution des kystes a été illustrée, mettant en évidence un zonage de la lagune avec une abondance plus importante au niveau des zones conchylicolesThe ballast water discharges in Bizerte harbor and shellfish aquaculture farms in Bizerte lagoon can be potentials sources with an interest in the introduction of harmful species, especially those that are potentially toxic like A. pacificum, A. pseudogonyaulax, A.minutum, A.affine and Polysphaeridium zoharyi, without neglecting the role of currents in the distribution of cysts. The study of the vessel traffics for 7 years before our prospection in Bizerte harbour have showing that the percentage of vessels coming from the Pacific road is around 14%. In order to identify species of Dinoflagellates producing resting cysts incriminated on potentially toxic blooms, a high spatial resolution sampling of the surface sediment for the identification and counting of resistance cysts was carried out to estimate the cyst density based on sedimentary characteristics, water content, organic matter, granulometry, abundance of vegetative forms and environmental factors. This study allowed the identification of 48 morphotypes of dinoflagellate cysts, mainly dominated by Brigantidinium simplex, Votadinum spinosum, Alexandrium pacificum, Alexandrium pseudogonyaulax and Lingulodinum machaerophorum. The density of cysts ranged from 1276 to 20126 cysts g-1 dry sediment. Significant differences between cyst distributions were recorded, which enabled us to distinguish two areas in the Bizerte lagoon. Particular attention was given to the complex Alexandrium tamarense (HABs). In addition, morphological examination and ribotyping of vegetative cells obtained from microalgal cultures following extraction process, isolation of resistance cysts from sediment, and their germination led to the production of monospecific culture: ABZ1 characterized by a μ (growth rate) = 0.33 day-1 and a generation time T = 2.1 day. These reviews have confirmed the newly identified genus and species in the Mediterranean sea and mentioned specifically in the lagoon of Bizerte: Alexandrium pacificum. The toxin profile obtained from an extract of ABZ1 culture in exponential phase revealed the presence of N-sulfocarbamoyl toxin C1 (9.82 pg toxin Cell-1), the GTX6 (3.26 pg toxin Cell-1), carbamoyl and the Neo-STX toxin (0.38 pg cell toxin-1), representing 2.8% of total toxins of this strain.A correlation between the abundance of cysts of Alexandrium pacificum and water percentage well as organic matter was found. Moreover, sediment fraction <63μm proved potentially favorable to initiate Alexandrium pacificum blooms in Bizerte lagoon. A significant difference in the cyst distribution diagram was shown, highlighting a zoning of the lagoon with a greater abundance in shellfish farm areas
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Chang, Jia-Wei, and 張家維. "Isolation and characterization of paralytic shellfish toxins from Alexandrium minutum Halim of Taiwan and the routine monitoring of paralytic shellfish toxins." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/19602378076867221273.
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碩士國立臺灣大學
漁業學系
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This is the first research ever attempting to isolate two components of paralytic shellfish toxins from Alexandrium minutum Halim in Taiwan. The two toxins were obtained by means of two different yet successive preparative chromatography on the water soluble extract that taken from a mass culture of Alexandrium minutum Halim AM-1. The sample was first seperated by a gel filtration chromatography, then the toxin fraction obtained was then puried by an linear gradient elution with 0-0.025N acetic acid and a subsequent 0.027-0.03N acetic acid elution on the toxin fraction. Gonyautoxin-1 and Gonyautoxin-4 were thus purified and confirmed by 1H-NMR spectroscopic analysis. There exist two other minor toxins which have been confirmed yet not purified in A. minutum are Gonyautoxin-3 and Gonyautoxin-2. Solution of pure Gonyautoxin-1 and Gonyautoxin-4 were found loosing their nature gradually within 12 days even in pH=3.3 acetic acid solution and a temperature below -20℃. Pure form of toxins was also found to degrade or to convert to its epimer in a solution of higher pH or higher temperature. A drying procedure such as lyophilization may cause degradation and interconversion. The second portion of this research is the routine monitoring result of paralytic shellfish toxins in the culturing shellfishes along the south western coast of Taiwan during the year of 1993- 1995. Among the three man-raised shellfishes, clam, oyster and purple clam, only purple clam was found to be toxic occasionally. It was also found that almost all the toxic purple clams were from Pintung area. The toxic purple clams were found to contain Gonyautoxin-1, Gonyautoxin-2, Gonyautoxin-3, and Gonyautoxin-4 which were the same composition of toxins found in A. minutum collceted in the same area. Sometimes, the toxicity of purple clam may exceeded the quarantine allowance of U.S. or Japan by
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Lage, Sandra 1987. "Transfer and accumulation of paralytic and amnesic shellfish toxins in secondary consumers of the marine trophic chain." Master's thesis, 2010. http://hdl.handle.net/10451/2057.
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Tese de mestrado, Ecologia Marinha, 2010, Universidade de Lisboa, Faculdade de CiênciasResumo alargado em português disponível no documento
Paralytic and amnesic shellfish toxins can enter in the marine trophic chain by filterfeeding and benthic organisms. Then due to trophic interrelationships the toxins are transferred to theirs predators. In the last instance, top predators (marine mammals and sea birds) can be intoxicated after fed on primary and secondary consumers. The wild horse mackerel (Trachurus trachurus) was collected in NW and S Portuguese coast between September of 2009 and March of 2010. The results show for the first time that horse mackerel can accumulate high concentrations of PSTs in theirs gastrointestinal tract. Which increased the requirement of evaluated the dynamics of accumulation and elimination of PSTs in secondary consumer fish. Thus aquaculture fishes, white sea breams, were fed with toxin-contaminated cockles. After 5 days of toxin exposure, the fishes were fed with non toxic cockles during 10 days. In this feeding experiment, an increasing of toxin concentration over the exposure period was noticed in the fish gastrointestinal tract. B1 and dcSTX were the only toxins continuously detected during the exposure/elimination period, which reveal a slower elimination than the others PSTs. These two PSTs were also the main toxins in the mackerel toxin profile, which may suggest a specific PSTs elimination by fish species. Although AST were not detected in any mackerel specimen, in octopus (Octopus vulgaris) specimens captured in the same fishing area, domoic acid (DA) was detected in the digestive glands. This accumulation of DA in the octopus was previously identified. However this is the first time that DA was detected during periods of absence of ASP events. Plus DA was predominantly found in the cytosol which increased the evidence of a retention mechanism. Since DA as a hydrophilic compound should be easily release. This thesis supplies relevant data to the growing knowledge on the dynamics of accumulation and elimination of PSTs and AST in secondary consumers and on the toxin transfer in the marine food web.
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Chebib, Hanadie A. "The accumulation, biotransformation and elimination of paralytic shellfish toxins in Mytilus edulis as a function of prior seasonal exposure to natural blooms of Alexandrium excavatum." Thesis, 1992. http://spectrum.library.concordia.ca/4416/1/MM84714.pdf.
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In a transplant experiment, two geographically distinct populations of Mytilus edulis with different histories of contamination by Paralytic Shellfish Poisoning (PSP) toxins were exposed to natural blooms of the toxic dinoflagellate Alexandrium excavatum. Transplanted mussels were suspended in cages from the quai at the site of the experiment. Mussel and Alexandrium cells samples were collected periodically and their PSP toxin concentration and composition analysed by High Performance Liquid Chromatography (HPLC). The mussels encountered two successive blooms of A. excavatum differing in duration, maximum cell concentration and toxicity per cell. The shorter first bloom displayed cell concentrations an order of magnitude greater than the second bloom, but the toxicity of the cells increased by a factor of four during the latter. The two populations displayed different PSP toxin accumulation and elimination patterns during and after the first but not the subsequent bloom. During the first bloom, the maximum toxin concentration of chronically exposed mussels was twice that of the pristine mussels, but in terms of toxicity, the difference was less pronounced. Putative toxin transformation was examined in the two populations, based on comparisons of toxin profiles in Alexandrium cells and in mussel digestive glands and by comparison of temporal changes in toxin epimeric ratios in the two mussel populations. Prior exposure to toxic Alexandrium blooms appeared to have an effect on transformation of PSP toxins. During the first bloom, the toxin patterns of pristine mussels resembled those of the Alexandrium cells, but following a first exposure, the two mussel groups had comparable toxin patterns. Mussels which had not been pre-exposed to PSP toxins, seemed to accumulate less toxin on a total molar basis in the presence of high Alexandrium cell concentrations, but they contained a higher proportion of highly toxic derivatives, and detoxified more rapidly than previously exposed mussels
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Almeida, João Carlos Cristóvão Martins de. "Síndrome parética em gaivotas (Laridae): Qual é a etiologia?" Master's thesis, 2021. http://hdl.handle.net/10400.26/38922.
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A síndrome parética, de etiologia desconhecida, é uma das principais causas de admissão nos centros de recuperação de fauna selvagem em Portugal e afeta principalmente aves marinhas, como as gaivotas.
Entre outros, a intoxicação por biotoxinas marinhas paralisantes (PSP- Paralytic Shelfish Poisoning), nomeadamente a saxitoxina (STX), tem sido equacionada como um dos principais diagnósticos diferenciais, por desenvolver um quadro clínico compatível com esta síndrome.
O presente estudo teve como objetivo determinar a exposição de duas espécies de gaivotas à STX e correlacionar com a severidade da síndrome apresentada por estas espécies. Para esta finalidade, determinou-se as concentrações de saxitoxina, através de um ensaio imunoenzimático (ELISA), em amostras de fígado (n=23) das espécies de gaivota Larus fuscus (n = 17) e Larus michahellis (n = 6) admitidas ao Centro de Reabilitação de Animais Marinhos – CRAM / Ecomare entre agosto de 2019 e abril de 2021. Estes animais apresentavam um quadro clínico compatível com a síndrome parética.
Das 23 amostras analisadas, 3 apresentaram concentrações de STX entre 11,1ng/mL e 17,2 ng/mL, com uma frequência de 16% nos animais com suspeita de intoxicação por biotoxinas. Nas restantes amostras os valores de concentração de saxitoxina encontravam-se abaixo do LOQ.
Atendendo à problemática das biotoxinas na saúde humana e animal e tendo em conta os resultados preliminares obtidos neste estudo, reforça a importância da realização de estudos de biomonitorização da STX utilizando as gaivotas como biomonitores (animais no topo da cadeia alimentar e com uma ampla distribuição geográfica). A continuidade da realização destes estudos também se verifica importante para melhorar o conhecimento sobre a etiologia da síndrome parética que afeta estes animais.The paretic syndrome, of unknown etiology, is one of the main causes of admission to wildlife rescue centres in Portugal and it mainly affects seabirds such as seagulls. Among others, intoxication by paralytic marine biotoxins (PSP - Paralytic Shelfish Poisoning), namely saxitoxin (STX), has been considered as one of the main differential diagnoses, as it develops a clinical picture compatible with this syndrome. The present study aimed to determine the exposure of two species of gulls to STX and to correlate with the severity of the syndrome presented by these species. For this purpose, saxitoxin concentrations were determined by an enzyme immunoassay (ELISA) in liver samples (n = 23) of the species Larus fuscus (n = 17) and Larus michahellis (n = 6) that were admitted to the Centro de Reabilitação de Animais Marinhos - CRAM / Ecomare, between August 2019 and April 2021. Of the 23 samples analyzed, 3 presented saxitoxin values between 11.1 and 17.2 ng/mL, with a frequency of 16% of the animals with suspected saxitoxin poisoning. In the remaining samples, the saxitoxin concentration values were below the LOQ. Based on these preliminary results, and given the problem of biotoxins in human and animal health, it reinforces the importance of conducting STX biomonitoring studies using seagulls as biomonitors (animals at the top of the food chain and with a wide geographic distribution). The continuity of these studies is also important to improve knowledge about the etiology of the paretic syndrome that affects these animals.
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Jaime, Elke [Verfasser]. "Analytik und Vorkommen von Paralytic shellfish poisoning (PSP)-Toxinen in marinen Organismen / von Elke Jaime." 2003. http://d-nb.info/968060919/34.
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Rühl, Alexander [Verfasser]. "Entwicklung und Anwendung von flüssigchromatographischen Analyseverfahren zum Nachweis von Diarrhetic Shellfish Poisoning (DSP)-Toxinen / von Alexander Rühl." 2004. http://d-nb.info/971963800/34.
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黃振平. "Comparison of the Toxin Accumulation and Detoxification in Two Hiatula Species Exposed to Paralytic Shellfish Poison-containing Alexandrium Minutum Halim." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/98090819560150784505.
Full textAbstract:
碩士國立臺灣大學
漁業科學研究所
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Purple clam is a kind of shellfish of high economic importance in Taiwan. Since the paralytic shellfish poisoning (PSP) incidents due to the ingestion of contaminated purple clam occured in 1986 and 1991, the consumption and aquaculture industry of purple clam has been declining. According to the long term survey of toxic shellfish monitoring, it was noted that most of the toxic cases were related to one of the purple clam species, Hiatula rostrata, but none to H. diphos, another popular species cultured. In this research we used a high performance liquid chromatography for PSP toxin analysis in Alexandrium minutum, known as the toxin producing organism responsible for the PSP in Taiwan, and purple clams. Accumulation and detoxification of toxins in these two hiatula species were compared after continously feeding with toxic A. minutum for 24 days and nontoxic Isochrysis and Pavlova for another 24 days. Toxin metabolism and translocation in the purple clams were also studied and compared between two species. The result showed that both Hiatula species accumulated the toxins according to the amount of filtered A. minutum cells. Although H. diphos showed a higher rate in toxicity increase than H. rostrata, both species showed a similar level of highest toxicity in the experiment period. Most of the ingested algal toxins remained in the digestive glad of the clam. Some of the toxins were translocation to muscle tissue after several days. It was found that were the same feeding behavior H. diphos showed toxicity in muscle the earlier than H. rostrata. There was a consitency on dates when the digestive gland and muscle showed their highest toxicity. However H. rostrata showed it's highest toxicity in muscle one sampling period after the date that the digestive gland had its highest toxicity. Generally, GTX-Ⅰand GTX-Ⅱwer more stable that the after two, GTX-Ⅲ and GTX-Ⅳ in the clam tissue due to the result that GTX-Ⅲ and GTX-Ⅳ remained almost the same concentration in the tissue during feeding period. From the monitoring survey of toxic purple clam cultured in different areas along the south western coast of Taiwan it was noticed that the toxic clams were all from Tungkang of Pingtung. They had toxicities exceeding the safety level in several occasions. During the study period there seems no significant seasonal variation of the occurrence of toxic clam due to the widely ditsribution of the toxic specimens in almost every months of the year. There was a coincidence to show the toxic clams were H.rostrata and cultured mainly in Tungkang area and nontoxic ones were H. diphos, cultured elsewhere. Since our result showed no significant difference in toxin accumulation removal between these two Hiatula species, we speculated the geographic distribution of toxic clams was due the different environment and different culture behavior that brought the blooming of toxic algae and contaminated the clams.
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Helbig, Tina [Verfasser]. "Analytik und Vorkommen lebensmittelrechtlich relevanter mariner Biotoxine unter besonderer Berücksichtigung von Paralytic Shellfish Poisoning (PSP)-Toxinen und Tetrodotoxinen (TTXs) / von Tina Helbig." 2010. http://d-nb.info/1008204323/34.
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Smith, Christa Belle. "Nitrogen nutrition of Alexandrium tamarense : using δ¹⁵N to track nitrogen source used for growth." Thesis, 2009. http://hdl.handle.net/2152/ETD-UT-2009-05-82.
Full textAbstract:
Alexandrium tamarense is a harmful algal species that can produce saxitoxins, a suite of powerful neurotoxins that bioaccumulate up the food chain and can have severe economic and health impacts. With harmful algal blooms increasing temporally and spatially, it is important for us to understand the relationship between harmful algal blooms and nutrients, particularly nitrogen from anthropogenic sources. To this end, the stable nitrogen isotopic composition (δ¹⁵N) of medium nitrate, algal cells and toxin in both nitrogen-replete and nitrogen-limited batch cultures of A. tamarense were measured in order to assess the potential for using the δ¹⁵N of the toxin as a tracer of the nitrogen source used for growth.
A. tamarense cells grown under nitrate-replete conditions were depleted by 1.5‰ relative to the growth medium, and saxitoxin was depleted by 1.5‰ relative to the whole cells. Under nitrate-limiting conditions, the isotopic difference between cells and saxitoxin changed as nitrate in the growth medium was depleted, indicating uncoupling of toxin synthesis and cell growth rates under changing external nutrient conditions. Determination of the absolute magnitude of the isotopic differences between the medium nitrate and either the cells or the saxitoxin was confounded by 1) using two different nitrate sources – one nitrate source was used to grow the inoculum and a different nitrate source was used for the experimental medium - with different ‰ values and 2) the presence of an unidentified, isotopically-light, nitrogen blank in the low-nitrate medium samples.
I conclude that STX nitrogen isotope values have the potential to be used as nitrogen source indicators. However, overall fractionation between whole cells and STX is unknown due to the uncoupling between cell growth and STX synthesis observed during my nitrogen-limited experiment. Based on previous research on cell growth and toxin production dynamics under different nutrient regimes, it is also reasonable to assume that the observed results here may differ if a different nitrogen source was utilized by the cells for STX production. Further research could include isotope analysis of cultures grown on different nitrogen sources, such as ammonium and urea; isotopic analysis of additional compounds, such as amino acids; or use of additional stable isotopes, such as C or O.text