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| Registros recuperados: 28 | |
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| Gueguen, Marielle; Bardouil, Michele; Baron, Regis; Lassus, Patrick; Truquet, Philippe; Massardier, Julie; Amzil, Zouher. |
| Contamination of shellfish by paralytic shellfish poisoning ( PSP) toxins poses an economic threat to shellfish farmers. As contaminated shellfish cannot be harvested for long periods of time, it would be very useful to develop processes to optimise and shorten their detoxification. In this study, Pacific oysters Crassostrea gigas were first experimentally contaminated over a period of 13 days with a continuous flow of toxic Alexandrium minutum cultures at concentrations ranging from 150 to 200 cell ml(-1) ( toxin content after 13 days of contamination 438 mu g STX equiv. 100 g(-1) wet weight). Then, two different detoxification treatments were tested and showed detoxification rates greater than those observed in coastal environments. The first treatment... |
| Tipo: Text |
Palavras-chave: Alexandrium minutum; Crassostrea gigas; Detoxification; Inorganic matter; Organic matter; PSP; Paralytic shellfish poisoning. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3896.pdf |
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| Haberkorn, Hansy; Lambert, Christophe; Le Goic, Nelly; Moal, Jeanne; Suquet, Marc; Gueguen, Marielle; Sunila, Inke; Soudant, Philippe. |
| This study assessed the effects of an artificial bloom of the toxin-producing dinoflagellate, Alexandrium minutum, upon nutrition related processes and reproductive output of the Pacific oyster, Crassostrea gigas. Oysters were exposed to A. minutum, Paralytic Shellfish Toxins (PST) producer and compared to a control batch of oysters fed Isochrysis galbana clone Tahitian (T.Iso). The experiment was performed in June 2008, when oysters were found ripe. Several physiological variables of oysters, such as PSTs accumulation, digestive gland and histological observations as well as spermatozoa quality, were measured at the end of the exposure. Results indicate that the digestive gland was greatly impacted upon A. minutum exposure. Monoacylglycerol and... |
| Tipo: Text |
Palavras-chave: Harmful algae; Alexandrium minutum; Oyster; Nutrition-related processes; Reproductive output. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00008/11927/8653.pdf |
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| Maestrini, Serge; Bechemin, Christian; Grzebyk, Daniel; Hummert, Christian. |
| Alexandrium minutum (strain AM89BM) has been grown in semi-continuous culture (0.2 vol. d super(-1)) in N-limiting (NO sub(3) super(-): PO sub(4) super(3-)=1.6 and 3.16), in P-limiting (N: P=160 and 80), and in N and P balanced (N: P=16) media. The toxin content in cells changed greatly according to the N: P ratio. Cells grown in N: P balanced condition showed an average total paralytic shellfish poisoning (PSP) content of 1.24 fmol cell super(-1). In N-limiting conditions, cells contained ca. 3 times less toxin with mean values of 0.41-0.45 fmol cell super(-1). In contrast, cells grown in P-limiting conditions contained on average 3.5 and 7 times more toxins than in the balanced N: P condition: 4.31 fmol cell super(-1) in the N: P=160 medium and 8.01 fmol... |
| Tipo: Text |
Palavras-chave: Alexandrium minutum; Phosphorus limitation; Toxin content; PSP. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00173/28422/26753.pdf |
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| Sousa, Celia; Compere, Chantal; Dreanno, Catherine; Crassous, Marie-pierre; Gas, Fabienne; Baus, Beatrice; Perrot, Hubert. |
| In this paper, a simple detection of a toxic algae, Alexandrium minutum, was developed using highly sensitive quartz crystal microbalance. In terms of performance, compared with other conventional analytical tools, the main interest of our immunosensor is based on a fast and direct detection of these living cells. This system requires the use of one monoclonal antibody directed against the surface antigen of A. minutum. We demonstrate that the whole living and motile algae are caught and detected. The high specificity of the biosensor is also demonstrated by testing several other dinoflagellate species. The frequency shift is correlated to the A. minutum cells concentration. This simple system is potentially promising for environmental monitoring purposes. |
| Tipo: Text |
Palavras-chave: Alexandrium minutum; Quartz microbalance; Microalgae; Immunosensor. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00194/30492/28897.pdf |
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| Boullot, Floriane; Castrec, Justine; Bidault, Adeline; Dantas, Natanael; Payton, Laura; Perrigault, Mickael; Tran, Damien; Amzil, Zouher; Boudry, Pierre; Soudant, Philippe; Hegaret, Helene; Fabioux, Caroline. |
| Paralytic shellfish toxins (PST) bind to voltage-gated sodium channels (Nav) and block conduction of action potential in excitable cells. This study aimed to (i) characterize Nav sequences in Crassostrea gigas and (ii) investigate a putative relation between Nav and PST-bioaccumulation in oysters. The phylogenetic analysis highlighted two types of Nav in C. gigas: a Nav1 (CgNav1) and a Nav2 (CgNav2) with sequence properties of sodium-selective and sodium/calcium-selective channels, respectively. Three alternative splice transcripts of CgNav1 named A, B and C, were characterized. The expression of CgNav1, analyzed by in situ hybridization, is specific to nervous cells and to structures corresponding to neuromuscular junctions. Real-time PCR analyses showed... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Sodium channel; Alternative splicing; Alexandrium minutum; Paralytic shellfish toxins. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00368/47877/47892.pdf |
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| Hermabessiere, Ludovic; Fabioux, C.; Lassudrie, Malwenn; Boullot, F.; Long, Marc; Lambert, Christophe; Le Goic, N.; Gouriou, Jeremie; Le Gac, Mickael; Chapelle, Annie; Soudant, P.; Hegaret, Helene. |
| This study investigated the effect of gametogenesis pattern and sex on levels of paralytic shellfish toxins (PST) accumulated by triploid oysters Crassostrea gigas exposed to a natural bloom of the toxic dinoflagellate Alexandrium minutum in the Bay of Brest (Western Brittany, France), over the summer 2014. Toxin accumulation in oysters was proposed to be influenced by the proportion of energy allocated to reproduction versus other metabolisms, as proposed by Haberkorn et al. (2010). Thus, we hypothesized that triploid oysters with different gametogenesis patterns (α or β, producing respectively numerous gametes or rare gametes) could result in differences in toxin accumulation. Toxin level could also be different according to the gender of the oysters. To... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Alexandrium minutum; Harmful algal bloom (HAB); Paralytic shellfish toxin (PST); Gametogenesis pattern; Triploid. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00307/41801/41010.pdf |
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| Fabioux, Caroline; Sulistiyani, Yeni; Haberkorn, Hansy; Hegaret, Helene; Amzil, Zouher; Soudant, Philippe. |
| Harmful algal blooms of Alexandrium spp. dinoflagellates regularly occur in French coastal waters contaminating shellfish. Studies have demonstrated that toxic Alexandrium spp. disrupt behavioural and physiological processes in marine filter-feeders, but molecular modifications triggered by phycotoxins are less well understood. This study analyzed the mRNA levels of 7 genes encoding antioxidant/detoxifying enzymes in gills of Pacific oysters (Crassostrea gigas) exposed to a cultured, toxic strain of A. minutum, a producer of paralytic shellfish toxins (PST) or fed Tisochrysis lutea (T. lutea, formerly Isochrysis sp., clone Tahitian (T. iso)), a non-toxic control diet, in four repeated experiments. Transcript levels of sigma-class glutathione S-transferase... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Alexandrium minutum; Paralytic shellfish toxins; Antioxidant enzymes; Detoxification enzymes; MRNA. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00275/38601/38623.pdf |
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| Pousse, Emilien; Flye-sainte-marie, Jonathan; Alunno-bruscia, Marianne; Hegaret, Helene; Rannou, Eric; Pecquerie, Laure; Marques, Goncalo M.; Thomas, Yoann; Castrec, Justine; Fabioux, Caroline; Long, Marc; Lassudrie, Malwenn; Hermabessiere, Ludovic; Amzil, Zouher; Soudant, Philippe; Jean, Fred. |
| As other filter-feeders, Crassostrea gigas can concentrate paralytic shellfish toxins (PST) by consuming dinoflagellate phytoplankton species like Alexandrium minutum. Intake of PST in oyster tissues mainly results from feeding processes, i.e. clearance rate, pre-ingestive sorting and ingestion that are directly influenced by environmental conditions (trophic sources, temperature). This study aimed to develop a mechanistic model coupling the kinetics of PST accumulation and bioenergetics in C. gigas based on Dynamic Energy Budget (DEB) theory. For the first time, the Synthesizing Units (SU) concept was applied to formalize the feeding preference of oysters between non-toxic and toxic microalgae. Toxin intake and accumulation were both dependent on the... |
| Tipo: Text |
Palavras-chave: Alexandrium minutum; Paralytic shellfish toxins (PST); Dynamic Energy Budget (DEB); Modelling; Pacific oyster. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00455/56662/58407.pdf |
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| Le Gland, Guillaume. |
| Since 2010, planktonic algae Alexandrium minutum, cause of the PSP (Paralytic Shellfish Poisoning) syndrome, has been proliferating in early summer in the bay of Daoulas, within the roadstead of Brest. During this internship, a model has been designed in order to derive these blooms from physical parameters (temperature, irradiance, nutrient supply, dilution rate …). In the model, A.minutum competes with 50 other plankton species with randomly attributed optimal temperature and nutrient uptake abilities. It turns out to reproduce well the bloom of 2012, with a correct date of maximum concentration and a relevant order of magnitude. It reproduces the order of magnitude of 2013 concentrations, but the bloom then is too spread in time around the maximum.... |
| Tipo: Text |
Palavras-chave: Alexandrium minutum; Phytoplancton; Efflorescence (bloom); Nutriments; Lumière; Température; Dilution; Absorption (uptake); Quota cellulaire; Croissance; Compétition; Modèle; Rade de Brest. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00209/32004/30442.pdf |
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| Lazerges, M; Perrot, H; Antoine, Elisabeth; Defontaine, Audrey; Compere, Chantal. |
| We report the immobilization on a gold surface of a 20-base DNA probe labeled with disulfide group and on the selective hybridization with the complementary 20-base DNA strand. The oligonucleotide probe is the complementary strand of a partial sequence of the gene encoding for a large ribosomal RNA sub-unit which is a coding sequence of Alexandrium minutum DNA, a microalgae that produces neurotoxins responsible for paralytic shellfish poisoning on European and Asian coasts. The kinetics of DNA probe immobilization and hybridization were monitored in situ by using a 27 MHz quartz crystal microbalance under controlled hydrodynamic conditions. The frequency of the setup is stable to within a few hertz, corresponding to the nanogram, scale, for 3 h and makes... |
| Tipo: Text |
Palavras-chave: DNA; Alexandrium minutum; Microbalance. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1354.pdf |
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| Andrieux-loyer, Francoise; Philippon, Xavier; Bally, Gabriel; Kerouel, Roger; Youenou, Agnes; Le Grand, Jacqueline. |
| The macrotidal estuary of Penze (Brittany, Western part of the Channel, France) has been subjected to recurrent annual toxic blooms of Alexandrium minutum since 1988. This study aims to specify the phosphorus dynamics and bioavailability in sediments in order to improve our understanding of Alexandrium occurrences. Sediment-P pools and diffusive phosphate fluxes were studied under similar hydrodynamic conditions, in the intermediate estuary in May, June and July 2003 and along the salinity gradient from August 2004 to June 2005. The results highlight a decrease in bioavailable phosphorus (iron and organic bound) from the inner part of the estuary seaward. The ratio of iron-bound phosphorus to iron-oxyhydroxides is lower in the inner and intermediate... |
| Tipo: Text |
Palavras-chave: Sequential extraction; Sediment phosphorus; Pore water; Phosphate fluxes; Estuary; Alexandrium minutum. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4306.pdf |
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| Labry, Claire; Erard-le Denn, Evelyne; Chapelle, Annie; Fauchot, Juliette; Youenou, Agnes; Crassous, Marie-pierre; Le Grand, Jacqueline; Lorgeoux, Benedicte. |
| The understanding of the dominance of one species with respect to others is a pertinent challenge in HAB growth dynamics studies and the nutrient supply mode is one of the factors potentially involved. The competition for phosphorus (P) between a toxic species, Alexandrium minutum, and a non-toxic species, Heterocapsa triquetra, was studied (1) along a gradient of P depletion, (2) testing different P depletion degrees before a single PO4 supply and (3) experimenting different PO4 supply frequencies. In conditions Of PO4 depletion, H. triquetra stopped growing after two days both in monospecific and mixed batch cultures whereas A. minutum grew progressively from day 2 until the end of the experiment. This time-lag growth of A. minutum is associated to its... |
| Tipo: Text |
Palavras-chave: Semi continuous culture; Batch culture; Ecophysiology; Pulse; Phosphorus storage; Dinoflagellates; Heterocapsa triquetra; Alexandrium minutum. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4067.pdf |
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| Lassus, Patrick; Bardouil, Michele; Masselin, Pierre; Naviner, Magali; Truquet, Philippe. |
| A sea water recirculating flume was especially designed in the framework of this study. It improves physiological and ecophysiological evaluation of a 25 oysters (c. gigas) set fed on PSP toxic A. minutum cultures and then detoxified with commonly used aquaculture species (I. galbana, T. suecica, S. costatum, T. weissflogii). Chlorophyll a levels are kept steady in each case and adjusted in order to reach the same food value in each tank (0,5 mg/l TPM). When exposed to the mildly toxic species A. minutum (0,5 pg.eq.STX.cel-1) oysters depict a reduced clearance rate, food uptake and shell-valves activity (compared to non-toxic algal diets). The same physiological parameters do not show any significant differences when oysters are exposed to the control al... |
| Tipo: Text |
Palavras-chave: Épuration; Crassostrea gigas; Alexandrium minutum; PSP; Écophysiologie; Depuration; C. gigas; A. minutum; PSP; Ecophysiology. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00139/25021/23126.pdf |
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| Balti, Rafik; Brodu, Nicolas; Zhang, Jiaxuan; Amzil, Zouher; Drouin, Delphine; Sechet, Veronique; Masse, Anthony. |
| The Paralytic shellfish neurotoxins (PST) are of increasing interest for biomedical applications. The chemical synthesis is often complex and expensive that’s why the purification by membrane filtration of PST from Alexandrium minutum dinoflagellate was investigated. Disrupted micro-alga cells by ultrasonic treatment were diafiltred to let pass toxins through an ultrafiltration membrane. Then, the mean permeate was concentrated and diafiltrated by nanofiltration. Mean permeate fluxes equal to 187, 135 and 135 L.h–1.m-2 were obtained during the first diafiltration, the concentration step and the final diafiltration respectively. Up to 57 % (mol/mol) and 78 % (mol/mol) of organic matters and salts were removed respectively. Divalent ions were sparsely... |
| Tipo: Text |
Palavras-chave: Paralytic shellfish poisoning; Nanofiltration; Membrane; Alexandrium minutum; Purification. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00451/56286/57865.pdf |
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| Remize, Marine; Planchon, Frederic; Loh, Ai Ning; Le Grand, Fabienne; Lambert, Christophe; Bideau, Antoine; Bidault, Adeline; Corvaisier, Rudolph; Volety, Aswani; Soudant, Philippe. |
| The synthetic pathways responsible for the production of the polyunsaturated fatty acids 22:6n-3 and 20:5n-3 were studied in the Dinophyte Alexandrium minutum. The purpose of this work was to follow the progressive incorporation of an isotopic label (13CO2) into 11 fatty acids to better understand the fatty acid synthesis pathways in A. minutum. The Dinophyte growth was monitored for 54 h using high-frequency sampling. A. minutum presented a growth in two phases. A lag phase was observed during the first 30 h of development and had been associated with the probable temporary encystment of Dinophyte cells. An exponential growth phase was then observed after t30. A. minutum rapidly incorporated 13C into 22:6n-3, which ended up being the most 13C-enriched... |
| Tipo: Text |
Palavras-chave: PUFA synthesis; 22:6n-3; DHA; PKS pathway; Dinophyte; Alexandrium minutum; Encystment. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76562/77688.pdf |
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| Registros recuperados: 28 | |
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