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| Registros recuperados: 37 | |
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| Medhioub, Walid; Sechet, Veronique; Truquet, Philippe; Bardouil, Michele; Amzil, Zouher; Lassus, Patrick; Soudant, Philippe. |
| Growth and spirolide production of the toxic dinoflagellate Alexandrium ostenfeldii (Danish strain CCMP1773) were studied in batch culture and a photobioreactor (continuous cultures). First, batch cultures were grown in 450 mL flasks without aeration and under varying conditions of temperature (16 and 22 degrees C) and culture medium (L1, f/2 and L1 with addition of soil extract). Second, cultures were grown at 16 degrees C in 8 L aerated flat-bottomed vessels using L1 with soil extract as culture medium. Finally, continuous cultures in a photobioreactor were conducted at 18 degrees C in L1 with soil extract; pH was maintained at 8.5 and continuous stirring was applied. This study showed that A. ostenfeldii growth was significantly affected by temperature.... |
| Tipo: Text |
Palavras-chave: Alexandrium ostenfeldii; Batch; Growth; Photobioreactor; Spirolide production. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00049/16050/15784.pdf |
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| Jauffrais, Thierry; Marcaillou-le Baut, Claire; Herrenknecht, Christine; Truquet, Philippe; Sechet, Veronique; Nicolau, Elodie; Tillmann, Urban; Hess, Philipp. |
| Azadinium spinosum (Elbrächter and Tillmann), a small marine dinoflagellate, has been recently described as a de novo producer of azaspiracid-1 and -2 (AZA1 and -2) diarrhoeic toxins. A culture of A. spinosum was established in our laboratory and optimised for pilot-scale production of this organism, to evaluate and understand AZA1 and -2 accumulation and biotransformation in blue mussels (Mytilus edulis) fed with A. spinosum. Adult mussels were continuously exposed to A. spinosum over 1 week in 160 L cylindrical conical tanks. Three different diets were tested for contamination: 5000, 10 000 cells mL−1 of A. spinosum and a mixture of 5000 cells mL−1 of A. spinosum with 5000 cells mL−1 of Isochrysis aff. galbana (T-Iso, CCAP 927/14). During the subsequent... |
| Tipo: Text |
Palavras-chave: Azaspiracid; Azadinium spinosum; Marine biotoxins; AZA; Tissue distribution; Histology; Bivalve molluscs; Liquid chromatography coupled to tandem mass spectrometry. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00088/19877/17566.pdf |
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| Reveillon, Damien; Abadie, Eric; Sechet, Veronique; Brient, Luc; Savar, Veronique; Bardouil, Michele; Hess, Philipp; Amzil, Zouher. |
| beta-N-methylamino-L-alanine (BMAA) is a neurotoxic non-protein amino acid suggested to be involved in neurodegenerative diseases. It was reported to be produced by cyanobacteria, but also found in edible aquatic organisms, thus raising concern of a widespread human exposure. However, the chemical analysis of BMAA and its isomers are controversial, mainly due to the lack of selectivity of the analytical methods. Using factorial design, we have optimized the chromatographic separation of underivatized analogues by a hydrophilic interaction chromatography coupled to tandem mass spectrometry (HILIC-MS/MS) method. A combination of an effective solid phase extraction (SPE) clean-up, appropriate chromatographic resolution and the use of specific mass spectral... |
| Tipo: Text |
Palavras-chave: Cyanotoxins; BMAA; DAB; AEG; HILIC-MS/MS; Cyanobacteria; Bivalve mollusks; French Mediterranean. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00245/35579/34112.pdf |
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| Brissard, Charline; Herve, Fabienne; Sibat, Manoella; Sechet, Veronique; Hess, Philipp; Amzil, Zouher; Herrenknecht, Christine. |
| The presence of Ostreopsis cf. ovata on the Mediterranean coast represents a serious concern to human health due to production of toxins–putative palytoxin and ovatoxins (ovatoxin-a, -b, -c, -d, -e, -f and -g). However, purified ovatoxins are not widely available and their toxicities are still unknown. In the present study, we report on HR LC-MS/MS analysis of a French Ostreopsis cf. ovata strain (IFR-OST-0.3 V) collected at Villefranche-sur-Mer (France) during a bloom in 2011. Investigation of this strain of Ostreopsis cf. ovata cultivated in our laboratory by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS) confirmed the production of ovatoxins -a to–e and revealed the presence of a new ovatoxin... |
| Tipo: Text |
Palavras-chave: Ostreopsis cf. ovata; Palytoxin; Ovatoxins; U-HPLC/HR-MSn; Chromatographic separation. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00252/36302/34831.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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| Brissard, Charline; Herrenknecht, Christine; Sechet, Veronique; Herve, Fabienne; Pisapia, Francesco; Harcouet, Jocelyn; Lemee, Rodolphe; Chomerat, Nicolas; Hess, Philipp; Amzil, Zouher. |
| Ostreopsis cf. ovata produces palytoxin analogues including ovatoxins (OVTXs) and a putative palytoxin (p-PLTX), which can accumulate in marine organisms and may possibly lead to food intoxication. However, purified ovatoxins are not widely available and their toxicities are still unknown. The aim of this study was to improve understanding of the ecophysiology of Ostreopsis cf. ovata and its toxin production as well as to optimize the purification process for ovatoxin. During Ostreopsis blooms in 2011 and 2012 in Villefranche-sur-Mer (France, NW Mediterranean Sea), microalgae epiphytic cells and marine organisms were collected and analyzed both by LC-MS/MS and hemolysis assay. Results obtained with these two methods were comparable, suggesting ovatoxins... |
| Tipo: Text |
Palavras-chave: Ostreopsis cf. ovata; Palytoxin & ovatoxins; Culture; Seafood contamination; LC-MS/MS; Hemolysis assay; Mediterranean Sea. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00199/31025/29428.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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| 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; 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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| 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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| 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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| 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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| Martin-jezequel, Veronique; Calu, Guillaume; Candela, Leo; Amzil, Zouher; Jauffrais, Thierry; Sechet, Veronique; Weigel, Pierre. |
| Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA) production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine). Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen... |
| Tipo: Text |
Palavras-chave: Pseudo-nitzschia; Toxic diatoms; Nitrogen; Amino acids; Domoic acid. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00308/41912/41188.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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| 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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| 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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| 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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| Registros recuperados: 37 | |
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