Consulta: creatorFacets:"Sechet, Veronique"
Registros recuperados: 37
Data/hora: 07/06/2024 01:20:57

Effect of environmental and nutritional factors on growth and azaspiracid production of the dinoflagellate Azadinium spinosum
Provedor de dados: 5
Autores: 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

Pre-purification by membrane filtration of paralytic shellfish toxins from Alexandrium minutum dinoflagellate
Provedor de dados: 5
Autores: 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

Cytotoxicity, Fractionation and Dereplication of Extracts of the Dinoflagellate Vulcanodinium rugosum, a Producer of Pinnatoxin G
Provedor de dados: 5
Autores: 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

Extended evaluation of polymeric and lipophilic sorbents for passive sampling of marine toxins
Provedor de dados: 5
Autores: 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

Modélisation de la contamination des bivalves par les toxines d'Alexandrium spp. Rapport final
Provedor de dados: 5
Autores: 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
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00156/26711/24786.pdf

Dissolved azaspiracids are absorbed and metabolized by blue mussels (Mytilus edulis)
Provedor de dados: 5
Autores: 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

Growth and toxin production of Azadinium spinosum in batch and continuous culture
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00152/26348/24431.pdf

Immersed hollow fibres microfiltration (MF) for removing undesirable micro-algae and protecting semi-closed aquaculture basins
Provedor de dados: 5
Autores: 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

Effect of Dilution Rate on Azadinium spinosum and Azaspiracid (AZA) Production in Pilot Scale Photobioreactors for the Harvest of AZA1 and -2
Provedor de dados: 5
Autores: 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

COLNACOQ. Composés lipophiles naturels dans l’environnement des coquillages. Rapport final
Provedor de dados: 5
Autores: 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

Performances of dead-end ultrafiltration of seawater: from the filtration and backwash efficiencies to the membrane fouling mechanisms
Provedor de dados: 5
Autores: Masse, Anthony; Arab, Oumnia; Sechet, Veronique; Jaouen, Pascal; Pontie, Maxime; Sabiri, Nour-eddine; Plantier, Severine.
The present work investigates the fouling mechanisms of PVDF hollow fibre membrane (0.03 μm) during the dead end ultrafiltration at a fixed permeate flux (outside to inside configuration) of complex synthetic seawater composed by humic acids, alginic acids, inorganic particles and numerous salts at high concentrations. Short term ultrafiltration experiments at 100 L.h-1.m-2 show that the optimal specific filtered volume seems to be equal to 50 L.m-2. A residual fouling resistance equal to 2.1010 m-1 is added after each cycle of filtration during 8h of ultrafiltration at 100 L.h-1.m-2 and 50 L.m-2. Most of the fouling is reversible (80%). Organics are barely (15% of humic acids) retained by the membrane. Backwash efficiency drops during operation which...
Tipo: Text
Palavras-chave: Seawater; Ultrafiltration; Fouling membrane; Alginic acids; Humic acids.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00286/39716/38172.pdf

Production and Isolation of Azaspiracid-1 and -2 from Azadinium spinosum Culture in Pilot Scale Photobioreactors
Provedor de dados: 5
Autores: 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

Gut passage times in two bivalve molluscs fed toxic microalgae: Alexandrium minutum, A-catenella and Pseudo-nitzschia calliantha
Provedor de dados: 5
Autores: 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

Impact of granular filtration on ultrafiltration membrane performance as pre-treatment to seawater desalination in presence of algal blooms
Provedor de dados: 5
Autores: Sabiri, Nour-eddine; Sechet, Veronique; Jaouen, Pascal; Pontie, Maxime; Masse, Anthony; Plantier, Severine.
To mitigate fouling of the ultrafiltration (UF) membrane and improve permeate quality, we coupled granular filters (GF) with UF membrane as a pre-treatment for reconstituted seawater in the presence of algal bloom. Mono and bilayer granular filtrations were led at a mean velocity of 10 m h(-1) over a 7-hour period. Both GF gave the same algal cell retention rate (similar to 63%) after 7 hours of filtration. Turbidity reduction rate was 50% for the monolayer filter and 75% for the bilayer filter. Resulting organic matter removal rate was 10% for the monolayer filter and 35% for the bilayer filter. Dissolved organic carbon removal was low (20%) with the bilayer filter and non-existent with the monolayer filter. GF-coupled UF reduced humic acids in the...
Tipo: Text
Palavras-chave: Algal bloom; Fouling; Granular filtration; Pre-treatment; Seawater; Ultrafiltration.
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00442/55315/56845.pdf

Systematic detection of BMAA (β-N-methylamino-L-alanine) and DAB (2,4-diaminobutyric acid) in mollusks collected in shellfish production areas along the French coasts
Provedor de dados: 5
Autores: 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

Dinophag. Programme de recherche sur Dinophysis dans les eaux littorales des Pays de la Loire
Provedor de dados: 5
Autores: Souchu, Philippe; Oger-jeanneret, Helene; Lassus, Patrick; Sechet, Veronique; Le Magueresse, Alain; Le Bihan, Veronique.
Ce document résume les conclusions du programme de recherche Dinophag réalisé par l’Ifremer avec l’aide de la Région Pays de la Loire de janvier 2011 à décembre 2012. Il est destiné à tous ceux qui se sont interrogés sur la place que tient la microalgue toxique Dinophysis dans l’économie littorale de notre Région. Les lecteurs y découvriront aussi que Dinophysis n’est pas vraiment une microalgue comme les autres et qu’il reste encore pour les chercheurs de nombreuses interrogations sur le déterminisme de son développement et de sa toxicité.
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00172/28368/26660.pdf

β-N-methylamino-l-alanine (BMAA) and isomers: Distribution in different food web compartments of Thau lagoon, French Mediterranean Sea
Provedor de dados: 5
Autores: 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

Effect of Nitrate, Ammonium and Urea on Growth and Pinnatoxin G Production of Vulcanodinium rugosum
Provedor de dados: 5
Autores: 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

Effect of Azadinium spinosum on the feeding behaviour and azaspiracid accumulation of Mytilus edulis
Provedor de dados: 5
Autores: 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

Influence of temperature, irradiance and pH on the physiology of Teleaulax amphioxeia
Provedor de dados: 5
Autores: Gaillard, Sylvain; Charrier, Aurelie; Carpentier, Liliane; Malo, Florent; Bougaran, Gael; Hegaret, Helene; Hess, Philipp; Sechet, Veronique.
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00617/72958/71990.pdf

Recherche d'acide okadaïque (et de ses dérivés) chez les bactéries associées aux dinoflagellés responsables d'intoxication diarrhéique, sur les côtes françaises
Provedor de dados: 5
Autores: 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
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00104/21575/19155.pdf

Pinnatoxines en lien avec l’espèce Vulcanodinium rugosum (II)
Provedor de dados: 5
Autores: 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
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00285/39635/38126.pdf

Ovatoxin-a and Palytoxin Accumulation in Seafood in Relation to Ostreopsis cf. ovata Blooms on the French Mediterranean Coast
Provedor de dados: 5
Autores: 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

Complex Toxin Profile of French Mediterranean Ostreopsis cf. ovata Strains, Seafood Accumulation and Ovatoxins Prepurification
Provedor de dados: 5
Autores: 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 &amp; ovatoxins; Culture; Seafood contamination; LC-MS/MS; Hemolysis assay; Mediterranean Sea.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00199/31025/29428.pdf

Pinnatoxines en lien avec l’espèce Vulcanodinium rugosum
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00094/20518/18190.pdf

Quantitative analysis of azaspiracids in Azadinium spinosum cultures
Provedor de dados: 5
Autores: 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

Pinnatoxin G is responsible for atypical toxicity in mussels (Mytilus galloprovincialis) and clams (Venerupis decussata) from Ingril, a French Mediterranean lagoon
Provedor de dados: 5
Autores: 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

Azaspiracid accumulation, detoxification and biotransformation in blue mussels (Mytilus edulis) experimentally fed Azadinium spinosum
Provedor de dados: 5
Autores: 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

Recherche de micro-organismes toxinogènes associés aux dinoflagellés responsables d'intoxication diarrhéique sur les côtes françaises
Provedor de dados: 5
Autores: 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
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00104/21510/19091.pdf

Alexandrium ostenfeldii growth and spirolide production in batch culture and photobioreactor
Provedor de dados: 5
Autores: 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

Toxicity screening of 13 Gambierdiscus strains using neuro-2a and erythrocyte lysis bioassays
Provedor de dados: 5
Autores: 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

Effects of Organic and Inorganic Nitrogen on the Growth and Production of Domoic Acid by Pseudo-nitzschia multiseries and P. australis (Bacillariophyceae) in Culture
Provedor de dados: 5
Autores: 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

Beta-N-Methylamino-L-Alanine: LC-MS/MS Optimization, Screening of Cyanobacterial Strains and Occurrence in Shellfish from Thau, a French Mediterranean Lagoon
Provedor de dados: 5
Autores: 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

Characterization of ovatoxin-h, a new ovatoxin analog, and evaluation of chromatographic columns for ovatoxin analysis and purification
Provedor de dados: 5
Autores: 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

Modelling the accumulation of PSP toxins in Thau Lagoon oysters (Crassostrea gigas) from trials using mixed cultures of Alexandrium catenella and Thalassiosira weissflogii
Provedor de dados: 5
Autores: 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

Spirolide uptake and detoxification by Crassostrea gigas exposed to the toxic dinoflagellate Alexandrium ostenfeldii
Provedor de dados: 5
Autores: Medhioub, Walid; Lassus, Patrick; Truquet, Philippe; Bardouil, Michele; Amzil, Zouher; Sechet, Veronique; Sibat, Manoella; Soudant, Philippe.
Oysters (Crassostrea gigas) were exposed 4 days to cultures of the toxic dinoflagellate Alexandrium ostenfeldii (strain CCMP1773) that produces spirolides belonging to fast acting toxins (FAT) and let depurate for 7 days. During depuration, oysters were either fed the non-toxic algae Isochrysis galbana Tahitian clone (T. Iso) or starved. The objectives of this experiment were to evaluate (i) spirolide uptake and depuration by oysters (ii) spirolide effects on oysters and (iii) oyster recovery according to food supply during depuration. A. ostenfeldii cells were filtered and ingested by oysters while faeces contained numerous intact cells of the toxic diet. This suggested that ingested cells were not totally digested by oysters. Contents of spirolides (SPX)...
Tipo: Text
Palavras-chave: Spirolides; Alexandrium ostenfeldii; Contamination; Depuration; Crassostrea gigas; Inflammatory responses.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00098/20953/18740.pdf

Metabolomic Analysis of Marine Microalgae Using High Resolution Mass Spectrometry for Taxonomic Comparisons and Screening of Marine Biotoxins
Provedor de dados: 5
Autores: 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
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00179/29037/27473.pdf