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| Registros recuperados: 37 | |
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| Sechet, Veronique; Quilliam, Michael; Lassus, Patrick. |
| L'hypothèse de la toxinogénèse bactérienne autonome dans le cadre des efflorescences marines toxiques de type DSP a été examinée. 18 souches bactériennes isolées à partir de culture de Prorocentrum lima et 12 souches obtenues à partir de prélèvements dans le milieu marin de Dinophysis sacculus (Baie de Vilaine) et de D. acuminata (Concarneau) ont été cultivées en milieu liquide, milieu de Shiba, pauvre en phosphore inorganique. La nouvelle espèce de bactérie présumée toxique, Roseobacter algicola, isolée préalablement à partir de P. lima, au laboratoire "Phycotoxines et Nuisances", a également été testée. Après extraction méthanolique et prépurification sur cartouches de silice, les résidus ont été estérifiés par le 9-antryldiazométhane afin d'être dosés... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00104/21575/19155.pdf |
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| Mondeguer, Florence; Abadie, Eric; Herve, Fabienne; Bardouil, Michele; Sechet, Veronique; Raimbault, Virginie; Berteaux, Tom; Zendong, Suzie Zita; Palvadeau, Hubert; Amzil, Zouher; Hess, Philipp; Fessard, Valérie; Huguet, Antoine; Sosa, Silvio; Tubaro, Aurelia; Aráoz, Rómulo; Molgó, Jordi. |
| Pour tenter d’apporter des réponses aux questions soulevées par une précédente étude commanditée pour approfondir les connaissances sur Vulcanodinium rugosum, l’organisme producteur de la Pinnatoxine G (PnTX G) (Hess et al., 2012), les objectifs de cette nouvelle étude sont les suivants : - Elargissement de la zone initiale de prélèvement d’Ingril à toute la lagune méditerranéenne et mise à profit de l’augmentation du nombre d’échantillons pour vérifier l’impact de l’effet matrice dans l’analyse LC-SM/MS. - Mise en culture en masse de Vulcanodinium rugosum et - Conduite d’une expérience de contamination in vivo sur des moules pour vérifier l’accumulation de la PnTX-G et comprendre les mécanismes de la métabolisation des PnTXs et de ses composés associés..... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00285/39635/38126.pdf |
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| Amzil, Zouher; Sibat, Manoella; Chomerat, Nicolas; Grossel, Hubert; Marco-miralles, Francoise; Lemee, Rodolphe; Nezan, Elisabeth; Sechet, Veronique. |
| Dinoflagellates of the genus Ostreopsis are known to cause (often fatal) food poisoning in tropical coastal areas following the accumulation of palytoxin (PLTX) and/or its analogues (PLTX group) in crabs, sea urchins or fish. Ostreopsis spp. occurrence is presently increasing in the northern to north western Mediterranean Sea (Italy, Spain, Greece and France), probably in response to climate change. In France, Ostreopsis. cf. ovata has been associated with toxic events during summer 2006, at Morgiret, off the coast of Marseille, and a specific monitoring has been designed and implemented since 2007. Results from 2008 and 2009 showed that there is a real danger of human poisoning, as these demonstrated bioaccumulation of the PLTX group (PLTX and ovatoxin-a)... |
| Tipo: Text |
Palavras-chave: Ostreopsis cf. ovata; Palytoxin; Ovatoxin-a; LC-MS/MS; Seafood. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00071/18230/15799.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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| Hess, Philipp; Herve, Fabienne; Abadie, Eric; Sechet, Veronique; Molgo, Jordi; Amzil, Zouher; Fessard, Valerie. |
| Suite à la découverte de la Pinnatoxine G comme agent responsable des toxicités atypiques à Ingril fin 2010, une étude a été commanditée afin d’approfondir les connaissances sur l’organisme producteur de cette toxine, Vulcanodinium rugosum, les toxines associées et leur toxicité. L’organisme, étant considéré « cryptique » dû à sa faible présence dans le milieu, a été suivi de manière plus proche à Ingril. Il est apparu dans la colonne d’eau en juillet et août 2012, et quelques échantillons ont pu être prélevés pour la mise en culture de souches supplémentaires. Une corrélation directe entre la croissance de l’organisme et la température est soupçonnée mais n’a pas encore pu être corroborée sur la période d’étude, faute d’un nombre suffisant... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00094/20518/18190.pdf |
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| Jauffrais, Thierry; Herrenknecht, Christine; Sechet, Veronique; Sibat, Manoella; Tillmann, Urban; Krock, Bernd; Kilcoyne, Jane; Miles, Christopher O.; Mccarron, Pearse; Amzil, Zouher; Hess, Philipp. |
| Azaspiracids (AZAs) are secondary metabolites of Azadinium spinosum, that have been shown to cause diarrhetic shellfish poisoning when accumulated in bivalve molluscs. We describe here an analytical procedure for the determination of AZAs in cultures of A. spinosum with a focus on the potential formation of AZA methyl-esters as artefacts in the extraction and sample pre-treatment. A. spinosum cells were collected from bioreactor cultures, using centrifugation or filtration. Different extraction procedures were evaluated for formation of methyl-ester artefacts, yield, and matrix effects. Filtration of cultures using glass-fibre filters led to increased formation of methyl-esters. Hence centrifugation is recommended for recovery of cells. The type of... |
| Tipo: Text |
Palavras-chave: Extraction procedure; Extraction artefact; Matrix effects; LC-MS/MS; Azaspiracid methyl ester; Dinoflagellate; Liquid chromatography-mass spectrometry. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00077/18812/16463.pdf |
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| Hess, Philipp; Abadie, Eric; Herve, Fabienne; Berteaux, Tom; Sechet, Veronique; Araoz, Romulo; Molgo, Jordi; Zakarian, Armen; Sibat, Manoella; Rundberget, Thomas; Miles, Christopher O.; Amzil, Zouher. |
| Following a review of official control data on shellfish in France, Ingril Lagoon had been identified as a site where positive mouse bioassays for lipophilic toxins had been repeatedly observed. These unexplained mouse bioassays, also called atypical toxicity, coincided with an absence of regulated toxins and rapid death times in mice observed in the assay. The present study describes pinnatoxin G as the main compound responsible for the toxicity observed using the mouse bioassay for lipophilic toxins. Using a well-characterised standard for pinnatoxin G, LC-MS/MS analysis of mussel samples collected from 2009 to 2012 revealed regular occurrences of pinnatoxin G at levels sufficient to account for the toxicity in the mouse bioassays. Baseline levels of... |
| Tipo: Text |
Palavras-chave: Cyclic imines; Shellfish toxin; Accumulation; Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS); Unexplained mouse toxicity. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00158/26960/25255.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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| Sechet, Veronique. |
| Ce document fait l'état des connaissances sur l'influence des bactéries au niveau de la dynamique des efflorescences marines à caractère toxique. Il prend également en compte les donnés récentes sur la production bactérienne autonome des "phycotoxines" et sur l'application de nouvelles technologies, immunologiques et génétiques. L'handicap majeur en toxicologie bactérienne est le manque d'information sur la composition spécifique des assemblages procaryotiques naturels dans les milieux aquatiques. Seul un infime pourcentage (moins de 1 %) des bactéries du milieu marin peut être isolé sur milieux gélosés. Des technologies nouvelles sont donc nécessaires pour 1°) mettre en évidence une éventuelle production bactérienne autonome des toxines, durant les... |
| Tipo: Text |
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| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00104/21510/19091.pdf |
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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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| Pisapia, Francesco; Holland, William C.; Hardison, D. Ransom; Litaker, R. Wayne; Fraga, Santiago; Nishimura, Tomohiro; Adachi, Masao; Lam Nguyen-ngoc,; Sechet, Veronique; Amzil, Zouher; Herrenknecht, Christine; Hess, Philipp. |
| Species in the epi-benthic dinoflagellate genus Gambierdiscus produce ciguatoxins (CTXs) and maitotoxins (MTXs), which are among the most potent marine toxins known. Consumption of fish contaminated with sufficient quantities of CTXs causes Ciguatera Fish Poisoning (CFP), the largest cause of non-bacterial food poisoning worldwide. Maitotoxins, which can be found in the digestive system of fish, could also contribute to CFP if such tissues are consumed. Recently, an increasing number of Gambierdiscus species have been identified; yet, little is known about the variation in toxicity among Gambierdiscus strains or species. This study is the first assessment of relative CTX- and MTX-toxicity of Gambierdiscus species from areas as widespread as the... |
| Tipo: Text |
Palavras-chave: Ciguatera fish poisoning; Gambierdiscus; Ciguatoxins; Maitotoxins; Neuro-2a assay; Erythrocyte lysis assay. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00374/48552/49411.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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| 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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| Lassus, Patrick; Amzil, Zouher; Baron, Regis; Sechet, Veronique; Barille, Laurent; Abadie, Eric; Bardouil, Michele; Sibat, Manoella; Truquet, Philippe; Berard, Jean-baptiste; Gueguen, Marielle. |
| In October and November 2003 a bloom of the toxic dinoflagellate Alexandrium catenella was observed in the North-east zone of Thau lagoon (French Mediterranean coast). Sea water samples were collected every hours to evaluate time-related variations of phytoplankton concentrations and to compare the relative ratio of A. catenella versus other phytoplankton species during the outbreak. From these observations, trials using recirculated sea water systems were performed to: i) evaluate the physiological effects on oyster of increasing proportions of A. catenella within a mixed microalgal diet where the non-toxic diatom Thalassiosira weissflogii was present at concentration: 1500 cells ml(-1), ii) compare the effect of two temperatures (12 degrees C and 18... |
| Tipo: Text |
Palavras-chave: Mediterranean Sea; Alexandrium catenella; Toxin content; Model; Crassostrea gigas; Paralytic shellfish poisoning. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2624.pdf |
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| Hess, Philipp; Mondeguer, Florence; Glauner, Thomas; Wust, Bernard; Sibat, Manoella; Zendong, Suzie Zita; Herrenknecht, Christine; Sechet, Veronique. |
| Out of the circa 5000 microalgae known, around 100 marine species of unicellular algae have been shown to produce several hundred biotoxins worldwide. Such biotoxins may be harmful to man through consumption of fish and shellfish exposed to such algae or through direct contact. Many official methods aimed at the detection of such toxins had traditionally been based on biological assays, due to the lack of reference compounds. Recently, legislation for shellfish safety in Europe introduced targeted MS screening for lipophilic toxins. Due to globalization of trade and climate change, there is a need to develop methods for untargeted screening to fully protect consumer safety, e.g. LC-HRMS. For this purpose we studied the metabolomes of marine microalgae... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00179/29037/27473.pdf |
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| Registros recuperados: 37 | |
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