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| Registros recuperados: 37 | |
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| Jauffrais, Thierry; Sechet, Veronique; Herrenknecht, Christine; Truquet, Philippe; Savar, Veronique; Tillmann, Urban; Hess, Philipp. |
| Azadinium spinosum, a small dinoflagellate isolated from the North Sea, is a producer of azaspiracids (AZAs), a group of biotoxins associated with human illness following ingestion of contaminated shellfish. Using batch and continuous cultures of A. spinosum, the present study investigated the effects of different environmental and nutritional factors (salinity, temperature, photon flux density, aeration, culture media, nitrogen sources, phosphate source, and N/P ratios) on growth, maximum cell concentration, and AZA cell quota. Azadinium spinosum grew in a wide range of conditions; from 10 ̊C to 26 ̊C and salinities from 30 to 40, under irradiances ranging from 50 μmol m−2 s−1 to 250 μmol m−2 s−1, with or without aeration. Growth and maximum cell... |
| Tipo: Text |
Palavras-chave: AZA; Chemostat; Dinophyceae; Nutrients; N/P ratio; Photobioreactor. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00149/26054/24411.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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| Geiger, Marie; Desanglois, Gwenaelle; Hogeveen, Kevin; Fessard, Valerie; Lepretre, Thomas; Mondeguer, Florence; Guitton, Yann; Herve, Fabienne; Sechet, Veronique; Grovel, Olivier; Pouchus, Yves-francois; Hess, Philipp. |
| Pinnatoxin G (PnTX-G) is a marine toxin belonging to the class of cyclic imines and produced by the dinoflagellate Vulcanodinium rugosum. In spite of its strong toxicity to mice, leading to the classification of pinnatoxins into the class of “fast-acting toxins”, its hazard for human health has never been demonstrated. In this study, crude extracts of V. rugosum exhibited significant cytotoxicity against Neuro2A and KB cells. IC50 values of 0.38 µg mL−1 and 0.19 µg mL−1 were estimated on Neuro2A cells after only 24 h of incubation and on KB cells after 72 h of incubation, respectively. In the case of Caco-2 cells 48 h after exposure, the crude extract of V. rugosum induced cell cycle arrest accompanied by a dramatic increase in double strand DNA breaks,... |
| Tipo: Text |
Palavras-chave: Dereplication; Cyclic imine; HRMS; Bioactivity; Pinnatoxins. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00156/26723/24802.pdf |
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| Zendong, Zita; Herrenknecht, Christine; Abadie, Eric; Brissard, Charline; Tixier, Celine; Mondeguer, Florence; Sechet, Veronique; Amzil, Zouher; Hess, Philipp. |
| Marine biotoxins are algal metabolites that can accumulate in fish or shellfish and render these foodstuffs unfit for human consumption. These toxins, released into seawater during algal occurrences, can be monitored through passive sampling. Acetone, methanol and isopropanol were evaluated for their efficiency in extracting toxins from algal biomass. Isopropanol was chosen for further experiments thanks to a slightly higher recovery and no artifact formation. Comparison of Oasis HLB, Strata-X, BondElut C18 and HP-20 sorbent materials in SPE-mode led to the choice of Oasis HLB, HP-20 and Strata-X. These three sorbents were separately exposed as passive samplers for 24 h to seawater spiked with algal extracts containing known amounts of okadaic acid (OA),... |
| Tipo: Text |
Palavras-chave: Passive sampling; Oasis HLB; Strata-X; LOPE; PDMS; SPATT. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00186/29756/28187.pdf |
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| Lassus, Patrick; Amzil, Zouher; Bardouil, Michele; Baron, Regis; Bohec, Madeleine; Bougrier, Serge; Garen, Pierre; Laabir, Mohamed; Leguay, Didier; Masselin, Pierre; Truquet, Philippe; Sechet, Veronique; Bablon, Clotilde; Berard, Jean-baptiste; Carre, Camille; Cheignon, Valerie; Lecamp, Sylvain; Mabit, Marie. |
| L'objectif général de l'étude est de simuler les épisodes de contamination de certains bivalves (huîtres et moules) par les toxines d'Alexandrium minutum et A. calenella à partir d'un module expérimental adapté, et en vue de construire un modèle de contamination applicable à ces espèces. Ce modèle sera ensuite susceptible d'être couplé aux modèles biologiques locaux (estuaire de Penzé et étang de Thau) de déterminisme des blooms, ainsi qu'aux modèles hydrodynamiques développés par différentes équipes (Ifremer, Université de Montpellier). La première année (2001-2002) était consacrée à la simulation des contaminations en estuaire de Penzé (Alexandrium minulum) et au développement de cultures en masse d'A. calenella de Thau en bioréacteurs. |
| Tipo: Text |
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| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00156/26711/24786.pdf |
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| Jauffrais, Thierry; Kilcoyne, Jane; Herrenknecht, Christine; Truquet, Philippe; Sechet, Veronique; Miles, Christopher O.; Hess, Philipp. |
| The relationship between azaspiracid shellfish poisoning and a small dinoflagellate, Azadinium spinosum, has been shown recently. The organism produces AZA1 and -2, while AZA3 and other analogues are metabolic products formed in shellfish. We evaluated whether mussels were capable of accumulating dissolved AZA1 and -2, and compared the toxin profiles of these mussels at 24 h with profiles of those exposed to live or lysed A. spinosum. We also assessed the possibility of preparative production of AZA metabolites by exposing mussels to semi-purified AZA1. We exposed mussels to similar concentration of AZAs: dissolved AZA1+2 (crude extract) at 7.5 and 0.75 µg L-1, dissolved AZA1+2 (7.5 µg L-1) in combination with Isochrysis affinis galbana, and lysed and live... |
| Tipo: Text |
Palavras-chave: Dissolved marine biotoxins; AZA; Tissue distribution; Bivalve molluscs; LC-MS/MS; Azaspiracid. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00136/24757/22867.pdf |
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| Jauffrais, Thierry; Sechet, Veronique; Herrenknecht, Christine; Tillmann, Urban; Krock, Bernd; Amzil, Zouher; Hess, Philipp. |
| Azaspiracids are lipophilic marine biotoxins causing gastrointestinal symptoms similar to DSP toxins. Since 1995, azaspiracids have been encountered in Europe, Africa and more recently in North and South America and Japan. The biological primary producer remained undiscovered during many years and has now been identified as Azadinium spinosum. The organism was grown using K modified medium, at 18°C with a PFD of 200 μmol.m-2.s-1 and a photoperiod of 16L/8D. Batch cultures were carried out using 75mL and 10L flasks, while continuous cultures were produced in 100L chemostats. Cells were recovered using centrifugation or filtration. Different extraction solvents and procedures as well as evaporation modes were evaluated for yield. Quantitation was carried out... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00152/26348/24431.pdf |
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| Castaing, Jean-baptiste; Masse, A.; Sechet, Veronique; Sabiri, N. -e.; Pontie, M.; Haure, Joel; Jaouen, P.. |
| In this study, an original use of immersed microfiltration membranes (mean pore size equal to 0.2 mu m) is investigated for the total removal of toxic dinoflagellates from seawater. Using a membrane autopsy and fouling model approach and the use of fouling indexes (called Pore Blocking Index, Pore Constriction Index and Cake Filtration Index), three dinoflagellate suspensions (Heterocapsa triquetra, Alexandrium minutum and Prorocentrum lima) have been microfiltered in order to study the influence of micro-algal species and its concentrations (1,000 and 30,000 cells/mL) on filtration yield and membrane fouling mechanisms. Results showed that all micro-algae have been retained after 180 min of microfiltration. At 30,000 cells/mL, permeate fluxes declined... |
| Tipo: Text |
Palavras-chave: Red tide; Dinoflagellate; Microfiltration; Membrane fouling mechanisms; Semi-closed aquaculture basins. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15246/14016.pdf |
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| Jauffrais, Thierry; Sechet, Veronique; Truquet, Philippe; Amzil, Zouher; Herrenknecht, Christine; Hess, Philipp. |
| Azadinium spinosum, a small dinoflagellate has recently been discovered and identified as the primary producer of azaspiracid-1 (AZA) and -2. Since AZA poisoning has been reported following consumption of contaminated shellfish it is important to have these toxins available for toxicological studies, and a sustainable production of AZAs as calibrants in monitoring programs without having to rely on natural events. In order to address this concern, continuous pilot scale cultures were carried out to evaluate the feasibility of AZA production from A. spinosum. Algae were cultured using two 100 L chemostats in series (R1 and R2), with agitation and pH control. Four different dilution rates were tested (0.15, 0.2, 0.25 and 0.3 day−1) to evaluate chemostat... |
| Tipo: Text |
Palavras-chave: Solid phase adsorption; Chemostat; Photobioreactor; Microalgae; LC-MS/MS; Tangential flow filtration. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00152/26349/24437.pdf |
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| Hess, Philipp; Geiger, Marie; Brochard, Solène; Lepretre, Thomas; Fessard, Valerie; Antignac, Jean-philippe; Dupont, Jacques; Sechet, Veronique; Vanel, Faustine; Mondeguer, Florence; Herve, Fabienne; Leborgne, Sabrina; Deslanglois, Gwenaëlle; Marshall, Lindsey; Rounds, Lucy; Guitton, Yann; Amzil, Zouher; Grovel, Olivier; Ruiz, Nicolas; Pouchus, Francois. |
| Cette étude s’est inscrite dans un contexte d’évaluation de la salubrité des mollusques bivalves destinés à la consommation humaine. Ces organismes peuvent en effet accumuler des toxines, en particulier de microalgues, en concentrations importantes, pouvant induire des intoxications chez les personnes les consommant. Afin d’assurer la protection des consommateurs, les toxines réglementées sont recherchées dans les coquillages par techniques physico-chimiques. En parallèle, les toxines émergentes, potentiellement produites par d’autres organismes que les micro-algues telles que les micromycètes, peuvent être detectées par l’utilisation du test de toxicité aigüe sur souris. Cependant, ce bio-essai présente de très nombreux inconvénients, notamment éthiques... |
| Tipo: Text |
Palavras-chave: Cytotoxicité; Toxicité sur larves de diptères; Activité antibactérienne; Bactéries marines; Toxines lipophiles; Micro-algues; Dinoflagellés; Micromycètes; Penicillium; Acide okadaïque; Azaspiracide; Pinnatoxine G; Vulcanodinium rugosum; Prorocentrum lima; Azadinium spinosum; Beauveria brongniartii. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00253/36470/35015.pdf |
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| Jauffrais, Thierry; Kilcoyne, Jane; Sechet, Veronique; Herrenknecht, Christine; Truquet, Philippe; Herve, Fabienne; Berard, Jean-baptiste; Nulty, Ciara; Taylor, Sarah; Tillmann, Urban; Miles, Christopher O.; Hess, Philipp. |
| Azaspiracid (AZA) poisoning has been reported following consumption of contaminated shellfish, and is of human health concern. Hence, it is important to have sustainable amounts of the causative toxins available for toxicological studies and for instrument calibration in monitoring programs, without having to rely on natural toxin events. Continuous pilot scale culturing was carried out to evaluate the feasibility of AZA production using Azadinium spinosum cultures. Algae were harvested using tangential flow filtration or continuous centrifugation. AZAs were extracted using solid phase extraction (SPE) procedures, and subsequently purified. When coupling two stirred photobioreactors in series, cell concentrations reached 190,000 and 210,000 cell·mL−1 at... |
| Tipo: Text |
Palavras-chave: Solid phase extraction; Photobioreactor; Chemostat; Dinoflagellate; Micro-algae; LC-MS/MS; Tangential flow filtration; Azaspiracid; HP-20. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19875/17526.pdf |
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| Gueguen, Marielle; Lassus, Patrick; Laabir, Mohamed; Bardouil, Michele; Baron, Regis; Sechet, Veronique; Truquet, Philippe; Amzil, Zouher; Barille, Laurent. |
| The occurrence of new phytoplankton species in a coastal area may be explained by the import of shellfish containing whole live algal cells in their digestive tracts. Indeed, shellfish containing toxic algal cells can induce both primary contaminations in safe areas ( initially free from toxic microalgae), and secondary contaminations of other shellfish growing in the same area via the faeces of the imported animals. To mitigate this problem, shellfish need to be placed in a separate holding tank and their intestinal content purged. For a deeper understanding of the risks associated with transferring contaminated shellfish, oysters ( Crassostrea gigas) and mussels ( Mytilus edulis) were purposely fed either Alexandrium minutum or A. catenella (... |
| Tipo: Text |
Palavras-chave: Risk assessment; Toxic phytoplankton; Uptake; Gut passage; Mytilus edulis; Crassostrea gigas. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3897.pdf |
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| Reveillon, Damien; Sechet, Veronique; Hess, Philipp; Amzil, Zouher. |
| The neurotoxin β-N-methylamino-L-alanine (BMAA) is naturally present in some microalgal species in the marine environment. The accumulation of BMAA has widely been observed in filter-feeding bivalves that are known to consume primary producers constituting the base of complex aquatic food webs. This study was performed to assess the occurrence of BMAA and isomers in mollusks collected from nine representative shellfish production areas located on the three French coasts (Channel, Atlantic and Mediterranean sites). The use of a highly selective and sensitive HILIC-MS/MS method, with D5DAB as internal standard, revealed the systematic detection of BMAA and DAB, in concentrations ranging from 0.20 to 6.7 μg g-1 dry weight of digestive gland tissues of... |
| Tipo: Text |
Palavras-chave: BMAA; Chaetoceros; Thalassiosira; Phaeodactylum; Bivalves; Seafood. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00297/40780/39784.pdf |
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| Reveillon, Damien; Abadie, Eric; Sechet, Veronique; Masseret, Estelle; Hess, Philipp; Amzil, Zouher. |
| The neurotoxin BMAA (β-N-methylamino-l-alanine) and its isomer DAB (2,4-diaminobutyric acid) have been detected in seafood worldwide, including in Thau lagoon (French Mediterranean Sea). A cluster of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease associated with BMAA, has also been observed in this region. Mussels, periphyton (i.e. biofilms attached to mussels) and plankton were sampled between July 2013 and October 2014, and analyzed using HILIC-MS/MS. BMAA, DAB and AEG (N-(2-aminoethyl)glycine) were found in almost all the samples of the lagoon. BMAA and DAB were present at 0.58 and 0.83, 2.6 and 3.3, 4.0 and 7.2 μg g−1 dry weight in plankton collected with nets, periphyton and mussels, respectively. Synechococcus sp., Ostreococcus... |
| Tipo: Text |
Palavras-chave: BMAA; Diatoms; Chaetoceros sp.; Seston; Mytilus galloprovincialis; HILIC-MS/MS. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00275/38607/37192.pdf |
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| Abadie, Eric; Kaci, Lamia; Berteaux, Tom; Hess, Philipp; Sechet, Veronique; Masseret, Estelle; Rolland, Jean-luc; Laabir, Mohamed. |
| ulcanodinium rugosum, a recently described dinoflagellate species producing a potent neurotoxin (pinnatoxin G), has been identified in French Mediterranean lagoons and was responsible for recurrent episodes of shellfish toxicity detected by mouse bioassay. Until now, the biology and physiology of V. rugosum have not been fully investigated. We studied the growth characteristics and toxicity of a V. rugosum strain (IFR-VRU-01), isolated in the Ingril lagoon in June 2009 (North-Western French Mediterranean Sea). It was cultivated in Enriched Natural Sea Water (ENSW) with organic (urea) and inorganic (ammonium and nitrate) nitrogen, at a temperature of 25 °C and irradiance of 100 μmol/m2·s−1. Results showed that ammonium was assimilated by cells more rapidly... |
| Tipo: Text |
Palavras-chave: Vulcanodinium rugosum; Pinnatoxin G; Ingril lagoon; Growth; Nitrogen source. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00276/38748/37290.pdf |
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| Jauffrais, Thierry; Contreras, Andrea; Herrenknecht, Christine; Truquet, Philippe; Sechet, Veronique; Tillmann, Urban; Hess, Philipp. |
| Azadinium spinosum, a small toxic dinoflagellate, was recently isolated and identified as a primary producer of azaspiracid toxins (AZAs). Previous experiments related to AZA accumulation in blue mussels upon direct feeding with A. spinosum revealed increased mussel mortality and had negative effects on the thickness of the digestive gland tubules. Therefore we conducted follow up experiments in order to study effects of A. spinosum on mussel feeding behaviour. Individual assessment of mussel feeding time activity (FTA), clearance rate (CR), filtration rate (TFR), absorption rate (AR), faeces and pseudofaeces production were carried out on mussel fed either toxic (A. spinosum) or non-toxic (Isochrisis aff. galbana (T-Iso)) diets. Furthermore, AZA... |
| Tipo: Text |
Palavras-chave: Bivalve molluscs; Mussel; Ecophysiology; AZA biotransformation; AZA accumulation; Trophic transfer; Dinoflagellate; Azaspiracid. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00090/20174/17832.pdf |
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| Registros recuperados: 37 | |
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