Consulta: creatorFacets:"Amzil, Zouher"
Registros recuperados: 83
Data/hora: 06/06/2024 13:22:12

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

Unsuspected intraspecific variability in the toxin production, growth and morphology of the dinoflagellate Alexandrium pacificum R.W. Litaker (Group IV) blooming in a South Western Mediterranean marine ecosystem, Annaba Bay (Algeria)
Provedor de dados: 5
Autores: Hadjadji, Imen; Laabir, Mohamed; Frihi, Hocine; Collos, Yves; Shao, Zhao Jun; Berrebi, Patrick; Abadie, Eric; Amzil, Zouher; Chomérat, Nicolas; Rolland, Jean-luc; Rieuvilleneuve, Fabien; Masseret, Estelle.
Physiological plasticity gives HABs species the ability to respond to variations in the surrounding environment. The aim of this study was to examine morphological and physiological variability in Alexandrium pacificum R.W. Litaker (Group IV) (former Alexandrium catenella) blooming in Annaba bay, Algeria. Monoclonal cultures of up to 30 strains of this neurotoxic dinoflagellate were established by the germination of single resting cysts from the surface sediment of this southern Mediterranean marine ecosystem. Ribotyping confirmed formally for the first time that A. pacificum is developing in Eastern Algerian waters. Toxin analyses of A. pacificum strains revealed substantial intraspecific variability in both the profile and toxin amount. However, the...
Tipo: Text
Palavras-chave: Alexandrium pacificum; Mediterranean; Toxin profile; Growth; Intraspecific variability.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00624/73620/73598.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

A Feedback Mechanism to Control Apoptosis Occurs in the Digestive Gland of the Oyster Crassostrea gigas Exposed to the Paralytic Shellfish Toxins Producer Alexandrium catenella
Provedor de dados: 5
Autores: Rolland, Jean-luc; Medhioub, Walid; Vergnes, Agnes; Abi-khalil, Celina; Savar, Veronique; Abadie, Eric; Masseret, Estelle; Amzil, Zouher; Laabir, Mohamed.
To better understand the effect of Paralytic Shellfish Toxins (PSTs) accumulation in the digestive gland of the Pacific oyster, Crassostrea gigas, we experimentally exposed individual oysters for 48 h to a PSTs producer, the dinoflagellate Alexandrium catenella. In comparison to the effect of the non-toxic Alexandrium tamarense, on the eight apoptotic related genes tested, Bax and BI.1 were significantly upregulated in oysters exposed 48 h to A. catenella. Among the five detoxification related genes tested, the expression of cytochrome P450 (CYP1A) was shown to be correlated with toxin concentration in the digestive gland of oysters exposed to the toxic dinoflagellate. Beside this, we observed a significant increase in ROS production, a decrease in...
Tipo: Text
Palavras-chave: Shellfish; Toxin; Biomarker; Expression; Phytoplankton.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00225/33606/32003.pdf

First Evidence of Palytoxin and 42-Hydroxy-palytoxin in the Marine Cyanobacterium Trichodesmium
Provedor de dados: 5
Autores: Kerbrat, Anne Sophie; Amzil, Zouher; Pawlowiez, Ralph; Golubic, Stjepko; Sibat, Manoella; Darius, Helene Taiana; Chinain, Mireille; Laurent, Dominique.
Marine pelagic diazotrophic cyanobacteria of the genus Trichodesmium (Oscillatoriales) are widespread throughout the tropics and subtropics, and are particularly common in the waters of New Caledonia. Blooms of Trichodesmium are suspected to be a potential source of toxins in the ciguatera food chain and were previously reported to contain several types of paralyzing toxins. The toxicity of water-soluble extracts of Trichodesmium spp. were analyzed by mouse bioassay and Neuroblastoma assay and their toxic compounds characterized using liquid chromatography coupled with tandem mass spectrometry techniques. Here, we report the first identification of palytoxin and one of its derivatives, 42-hydroxy-palytoxin, in field samples of Trichodesmium collected in...
Tipo: Text
Palavras-chave: Cyanobacteria; Trichodesmium; Palytoxin; 42-hydroxy-palytoxin; Clupeotoxism.
Ano: 2011
URL: https://archimer.ifremer.fr/doc/00040/15143/12576.pdf

Acclimation of the marine diatom Pseudo‐nitzschia australis to different salinity conditions: effects on growth, photosynthetic activity and domoic acid content
Provedor de dados: 5
Autores: Ayache, Nour; Hervé, Fabienne; Lundholm, Nina; Amzil, Zouher; Caruana, Amandine.
oxic Pseudo‐nitzschia australis strains isolated from French coastal waters were studied to investigate their capacity to adapt to different salinities. Their acclimation to different salinity conditions (10, 20, 30, 35 and 40) was studied on growth, photosynthetic capacity, cell biovolume and domoic acid (DA) content. The strains showed ability to acclimate to a salinity range from 20 to 40, with optimal growth rates between salinities 30 and 40. The highest cell biovolume was observed at the lowest salinity 20 and was associated with the lowest growth rate. Salinity did not affect the photosynthetic activity; Fv/Fm values and the pigment contents remained high with no significant difference among salinities. An enhanced production of zeaxanthin was,...
Tipo: Text
Palavras-chave: Acclimation; Climate change; Domoic acid; Pseudo-nitzschia australis; Physiology; Salinity.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00585/69684/67552.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

Bioactive extracellular compounds produced by the dinoflagellate Alexandrium minutum are highly detrimental for oysters
Provedor de dados: 5
Autores: Castrec, Justine; Soudant, P.; Payton, L.; Tran, D.; Miner, Philippe; Lambert, C.; Le Goic, N.; Huvet, Arnaud; Quillien, Virgile; Boullot, F.; Amzil, Zouher; Hegaret, Helene; Fabioux, C.
Blooms of the dinoflagellate Alexandrium spp., known as producers of paralytic shellfish toxins (PSTs), are regularly detected on the French coastline. PSTs accumulate into harvested shellfish species, such as the Pacific oyster Crassostrea gigas, and can cause strong disorders to consumers at high doses. The impacts of Alexandrium minutum on C. gigas have often been attributed to its production of PSTs without testing separately the effects of the bioactive extracellular compounds (BECs) with allelopathic, hemolytic, cytotoxic or ichthyotoxic properties, which can also be produced by these algae. The BECs, still uncharacterized, are excreted within the environment thereby impacting not only phytoplankton, zooplankton but also marine invertebrates and...
Tipo: Text
Palavras-chave: Harmful algal bloom (HAB); Crassostrea gigas; Paralytic shellfish toxins (PST); Bioactive extracellular compounds (BEC); Histology; Behavior.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00435/54637/56042.pdf

Report on the first detection of pectenotoxin-2, spirolide-A and their derivatives in French shellfish
Provedor de dados: 5
Autores: Amzil, Zouher; Sibat, Manoella; Royer, Florence; Masson, Nadine; Abadie, Eric.
In the context of the French Phytoplankton and Phycotoxins Monitoring Network (REPHY) programme, shellfish samples were harvested from different locations where harmful algae blooms were known to have occurred. For all shellfish samples found positive by the mouse bioassay for diarrhetic shellfish poisoning (DSP) toxins, liquid chromatography (LC) coupled with mass spectrometry (MS) was used to search for the following lipophilic toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs), yessotoxins (YTXs), spirolides (SPXs) and gymnodimines (GYMs). In order to investigate the presence of acyl-OAs and/or acyl-DTX-1,-2 (DTX-3), alkaline hydrolysis was performed on all samples, and LC/ MS analyses were carried out on the...
Tipo: Text
Palavras-chave: LC/MS analysis; Pectenotoxins; Spirolides; DSP toxins.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-6206.pdf

Toxines amnésiantes en France - Analyse par CLHP de l'acide domoïque et ses isomères - Bilan 1999 de la surveillance des toxines amnésiantes lié aux efflorescences à Pseudo-nitzschia toxiques
Provedor de dados: 5
Autores: Amzil, Zouher; Motteau, Lydie.
Dans le cadre du réseau de surveillance français en matière de toxines amnésiantes, l'acide domoïque a été détecté pour la première fois dans des échantillons de coquillages. En effet, le dosage de lacide domoïque (AD) par Chromatographie Liquide Haute Performance couplée à un détecteur Ultra Violet (CLHP/UV), méthode officielle, dans la partie comestible des bivalves est effectué dès que le seuil de 105 cellules par litre de diatomée du genre Pseudo-nitzchia spp. est dépassé. Les analyses réalisées pendant l'année 1999 ont révélé la présence de l'acide domoïque dans des bivalves prélevés en différents points des côtes françaises. Toutefois, la quantité maximale de toxine trouvée ne dépassait pas 3,2 µg d'AD par g de chair totale de coquillages, ce qui est...
Tipo: Text
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00104/21574/19154.pdf

Toxicité inexpliquée des moules de la baie de Lazaret (Toulon) entre novembre 1993 et mai 1994
Provedor de dados: 5
Autores: Amzil, Zouher; Marcaillou-le Baut, Claire; Bohec, Madeleine.
Depuis janvier 1993, des épisodes de forte toxicité des coquillages ont été observés lors des contrôles de routine en différents points des côtes françaises. Les souris ayant reçu des extraits de coquillages, par voie intrapéritonéale, présentaient des symptômes de type neurologique et mouraient au bout de 5 à 15 minutes. Cette toxicité n'a pu être attribuée à l'existence de phycotoxines connues. Les études préliminaires réalisées sur les glandes digestives de moules toxiques, récoltées lors d'un de ces épisodes (rade de Toulon), nous ont permis d'acquérir les données suivantes : le principe actif possède une forte polarité, il est thermostable, et il est stable dans le temps et en milieu acide. L'intoxication par voie orale chez la souris a permis de...
Tipo: Text
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00075/18596/16149.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

Influence of Environmental Factors on the Paralytic Shellfish Toxin Content and Profile of Alexandrium catenella (Dinophyceae) Isolated from the Mediterranean Sea
Provedor de dados: 5
Autores: Laabir, Mohamed; Collos, Yves; Masseret, Estelle; Grzebyk, Daniel; Abadie, Eric; Savar, Veronique; Sibat, Manoella; Amzil, Zouher.
Laboratory experiments were designed to study the toxin content and profile of the Alexandrium catenella strain ACT03 (isolated from Thau Lagoon, French Mediterranean) in response to abiotic environmental factors under nutrient-replete conditions. This dinoflagellate can produce various paralytic shellfish toxins with concentrations ranging from 2.9 to 50.3 fmol/cell. The toxin profile was characterized by carbamate toxins (GTX3, GTX4 and GTX5) and N-sulfocarbamoyl toxins (C1, C2, C3 and C4). C2 dominated at 12-18 degrees C, but only for salinities ranging from 10 to 25 psu, whereas GTX5 became dominant at temperatures ranging from 21 to 30 degrees C at almost all salinities. There was no significant variation in the cellular toxin amount from 18 degrees C...
Tipo: Text
Palavras-chave: Alexandrium catenella; PSP toxins; Temperature; Salinity; Light.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00148/25969/24056.pdf

Enhancement of domoic acid neurotoxicity on Diptera larvae bioassay by marine fungal metabolites
Provedor de dados: 5
Autores: Ruiz, Nicolas; Petit, Karina; Vansteelandt, Marieke; Kerzaon, Isabelle; Baudet, Joseph; Amzil, Zouher; Biard, Jean-francois; Grovel, Olivier; Pouchus, Yves Francois.
Peptaibols are small linear fungal peptides which are produced in the marine environment. They exhibit neurotoxicity by forming pores in neuronal membranes. This work describes their combine effect with domoic acid, a neurotoxic phycotoxin, on Diptera larvae. The Acute toxicity bioassay on this biological model was tested with a panel of different toxins (microbial, algal or fungal). It allowed the discrimination of neurotoxins and non-neurotoxic toxins, and an evaluation of the toxicity level (MED and ED50) which were correlated with published LD50 in mice for neurotoxins tested. The highest activities on this test were found for Na+ channel blockers tetrodotoxin (ED50 = 0.026 mg/kg) and saxitoxin (ED50 = 0.18 mg/kg). Domoic acid was less active with an...
Tipo: Text
Palavras-chave: Domoic acid; Peptaibol; Synergism; Neurotoxicity; Marine-derived fungal metabolite; Diptera larvae bioassay.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00002/11279/7886.pdf

Chemically mediated interactions between Microcystis and Planktothrix: Impact on their physiology and metabolic profiles
Provedor de dados: 5
Autores: Briand, Enora; Reubrech, Sébastien; Mondeguer, Florence; Sibat, Manoella; Hess, Philipp; Amzil, Zouher; Bormans, Myriam.
Freshwater cyanobacteria are well known for their ability to produce a wide variety of bioactive compounds, some of which have been described as allelochemicals. There is growing evidence that these secondary metabolites play an important role in shaping community composition through biotic interactions; however, for the most part, their biological role and mode of regulation of the production are poorly understood. In temperate eutrophic freshwaters, Microcystis and Planktothrix often co-occur, with Planktothrix being an early colonizer and Microcystis appearing subsequently. We tested if the production of a range of peptides by co-existing species could be regulated through interspecific interactions. Using a combined approach of co-cultures and analyses...
Tipo: Text
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00374/48515/48794.pdf

High resolution mass spectrometry for quantitative analysis and untargeted screening of algal toxins in mussels and passive samplers
Provedor de dados: 5
Autores: Zendong, Suzie Zita; Mccarron, Pearse; Herrenknecht, Christine; Sibat, Manoella; Amzil, Zouher; Cole, Richard B.; Hess, Philipp.
Measurement of marine algal toxins has traditionally focussed on shellfish monitoring while, over the last decade, passive sampling has been introduced as a complementary tool for exploratory studies. Since 2011, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been adopted as the EU reference method (No.15/2011) for detection and quantitation of lipophilic toxins. Traditional LC-MS approaches have been based on low-resolution mass spectrometry (LRMS), however, advances in instrument platforms have led to a heightened interest in the use of high-resolution mass spectrometry (HRMS) for toxin detection. This work describes the use of HRMS in combination with passive sampling as a progressive approach to marine algal toxin surveys. Experiments...
Tipo: Text
Palavras-chave: Monitoring; Marine toxins; Passive sampling; SPATT; Matrix effects.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00277/38848/37388.pdf

Contribution of marine invertebrates to Ciguatera poisoning : the case study of French Polynesia
Provedor de dados: 5
Autores: Darius, Ht; Viallon, J; Gatti, Cm; Chinain, M; Roué, M; Sibat, Manoella; Amzil, Zouher; Hess, Philipp; Vandersea, Mw; Litaker, Rw; Tester, Pa.
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00450/56181/57729.pdf

Toxicological Investigations on the Sea Urchin Tripneustes gratilla (Toxopneustidae, Echinoid) from Anaho Bay (Nuku Hiva, French Polynesia): Evidence for the Presence of Pacific Ciguatoxins
Provedor de dados: 5
Autores: Darius, Helene Taiana; Roue, Melanie; Sibat, Manoella; Viallon, Jerome; Gatti, Clemence Mahana Iti; Vandersea, Mark W.; Tester, Patricia A.; Litaker, R. Wayne; Amzil, Zouher; Hess, Philipp; Chinain, Mireille.
The sea urchin Tripneustes gratilla (Toxopneustidae, Echinoids) is a source of protein for many islanders in the Indo-West Pacific. It was previously reported to occasionally cause ciguatera-like poisoning; however, the exact nature of the causative agent was not confirmed. In April and July 2015, ciguatera poisonings were reported following the consumption of T. gratilla in Anaho Bay (Nuku Hiva Island, Marquesas archipelago, French Polynesia). Patient symptomatology was recorded and sea urchin samples were collected from Anaho Bay in July 2015 and November 2016. Toxicity analysis using the neuroblastoma cell–based assay (CBA-N2a) detected the presence of ciguatoxins (CTXs) in T. gratilla samples. Gambierdiscus species were predominant in the benthic...
Tipo: Text
Palavras-chave: Ciguatera poisoning; Ciguatoxins; Tripneustes gratilla; Sea urchin; Echinoidea; Gambierdiscus polynesiensis; Windowscreens; Artificial substrates; QPCR assays; CBA-N2a; LC-MS/MS.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00436/54716/56153.pdf

Three decades of data on phytoplankton and phycotoxins on the French coast: Lessons from REPHY and REPHYTOX
Provedor de dados: 5
Autores: Belin, Catherine; Soudant, Dominique; Amzil, Zouher.
In France, REPHY (Observation and Surveillance Network for Phytoplankton and Hydrology in coastal waters) and REPHYTOX (Monitoring Network for Phycotoxins in marine organisms) have been contributing to long-term time series on ocean health for more than 30 years. The aim of this paper is to describe these networks and to highlight their key results. Over the last 20 years, phytoplankton flora analysis on French coasts from the Channel to Mediterranean has shown that the five “emblematic” taxa are Chaetoceros, Skeletonema, Cryptophyceae, Leptocylindrus and Pseudo-nitzschia. The latter, together with the taxa of interest Dinophysis + Phalacroma, Alexandrium, and Karenia, have been consistently recorded along the entire French coastline. However, when taking...
Tipo: Text
Palavras-chave: Monitoring network; Phytoplankton time-series; Dominant species; DST-Diarrheic; Shellfish Toxins; PST-Paralytic Shellfish Toxins; AST-Amnesic Shellfish Toxins.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00617/72948/72699.pdf

REPHY (Réseau de Surveillance du Phytoplancton et des Phycotoxines). Méthodes de détection des phycotoxines diarrhéïques (DSP) et paralysantes (PSP). Méthodes biologiques sur souris
Provedor de dados: 5
Autores: Belin, Catherine; Marcaillou-le Baut, Claire; Amzil, Zouher; Ledoux, Martial.
This document describes and harmonizes detection methods of diarrheic (DSP) and paralytic (PSP) phycotoxins, for the laboratories of the Direction of Coastal Environment of IFREMER, which work in the framework of the French Phytoplankton and Phycotoxins Monitoring Network. These toxins, produced by a few phytoplankton species which regularly occur in sea water, accumulate in shellfish, which become toxic. Analysis is performed on an extract of digestive gland (DSP), or of total flesh (PSP), of shellfish. The described methods are meuse-tests, which are, at the present time, the only methods available to be used in the framework of a monitoring network. The method for diarrheic toxins is not standardized, with a threshold adapted for monitoring purposes. At...
Tipo: Text
Palavras-chave: Phycotoxines; Méthode de détection des toxines; Test-souris; Toxines diarrhéïques; DSP; Toxines paralysantes; PSP; Surveillance; Phycotoxins; Toxin detection method; Mouse-test; Diarrheic toxins; DSP; Paralytic toxins; PSP; Monitoring.
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00429/54106/55438.pdf

Viability, growth and toxicity of Alexandrium catenella and Alexandrium minutum (Dinophyceae) following ingestion and gut passage in the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Laabir, Mohamed; Amzil, Zouher; Lassus, Patrick; Masseret, Estelle; Tapilatu, Yosmina; De Vargas, Romain; Grzebyk, Daniel.
Adult oysters Crassostrea gigas were experimentally fed with Alexandrium catenella and Alexandrium minutum which are responsible for recurrent toxic blooms in French coastal waters. C. gigas produced faeces and pseudofaeces containing intact and viable temporary pellicular cysts of these two Paralytic toxin producing species. When incubated in favourable conditions, these pellicular cysts were able to germinate at high rates (between 74 and 94%) and the resulting vegetative cells divided with growth rates close to the non-ingested cells (control). The toxin profile of the vegetative cells originated from the germinated temporary cysts was analyzed by liquid chromatography/ fluorescence detection. Total toxin content of newly germinated cells was lower than...
Tipo: Text
Palavras-chave: Paralytic shellfish poisoning; Oysters; Cysts; Alexandrium minutum; Alexandrium catenella.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2622.pdf

Effets de l'algue toxique Alexandrium catenella sur le système de défense de l'huître creuse Crassostrea gigas
Provedor de dados: 5
Autores: Medhioub, Walid; Duchiron, Marie; Masseret, Estelle; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-luc.
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00172/28332/26618.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

Paralytic shellfish poison outbreaks in the Penze estuary: Environmental factors affecting toxin uptake in the oyster, Crassostrea gigas
Provedor de dados: 5
Autores: Lassus, Patrick; Baron, Regis; Garen, Pierre; Truquet, Philippe; Masselin, Pierre; Bardouil, Michele; Leguay, Didier; Amzil, Zouher.
Several experiments using a self-regulated system were conducted to define the factors likely to influence the uptake of paralytic shellfish poison (PSP) by oysters in the Penze estuary (France, Brittany). Each 4-day experiment was carried out in a recirculated sea water system using 15 Pacific oysters (Crassostrea gigas) separated from each other and supplied with unfiltered natural seawater containing alternatively toxic (Alexandrium minutum) or non-toxic (Skeletonema costatum) algal diets. The food supply and exposure times to toxic diets were determined according to field studies of the Upstream and downstream movement of patches containing A. minutum. The experimental parameters corresponded roughly to the hydrological conditions generally observed in...
Tipo: Text
Palavras-chave: Experimental contamination; Oyster toxicity; Dinophyceae; Toxin; PSP.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-400.pdf

Exposure to the Paralytic Shellfish Toxin Producer Alexandrium catenella Increases the Susceptibility of the Oyster Crassostrea gigas to Pathogenic Vibrios
Provedor de dados: 5
Autores: Abi-khalil, Celina; Lopez-joven, Carmen; Abadie, Eric; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-luc.
The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium...
Tipo: Text
Palavras-chave: Harmful algae; Environment; Interaction; Pathogens; Defense; Paralytic shellfish toxin.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00309/42016/41308.pdf

Exposure to the Neurotoxic Dinoflagellate, Alexandrium catenella, Induces Apoptosis of the Hemocytes of the Oyster, Crassostrea gigas
Provedor de dados: 5
Autores: Medhioub, Walid; Ramondenc, Simon; Vanhove, Audrey; Vergnes, Agnes; Masseret, Estelle; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-luc.
This study assessed the apoptotic process occurring in the hemocytes of the Pacific oyster, Crassostrea gigas, exposed to Alexandrium catenella, a paralytic shellfish toxins (PSTs) producer. Oysters were experimentally exposed during 48 h to the toxic algae. PSTs accumulation, the expression of 12 key apoptotic-related genes, as well as the variation of the number of hemocytes in apoptosis was measured at time intervals during the experiment. Results show a significant increase of the number of hemocytes in apoptosis after 29 h of exposure. Two pro-apoptotic genes (Bax and Bax-like) implicated in the mitochondrial pathway were significantly upregulated at 21 h followed by the overexpression of two caspase executor genes (caspase-3 and caspase-7) at 29 h,...
Tipo: Text
Palavras-chave: Shellfish; Toxins; Apoptosis; Gene expression.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00176/28744/27213.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

Paralytic Shellfish Poisoning on French Mediterranean coast in the autumn of 1998:Alexandrium tamarense as a causative agent
Provedor de dados: 5
Autores: Masselin, Pierre; Amzil, Zouher; Carreras, Antoni; Chiantella, Claude; Le Bec, Claude; Nezan, Elisabeth; Truquet, Philippe.
Tipo: Text
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00017/12871/9821.pdf

Lipophilic Toxin Profile in Mytilus galloprovincialis from the North Atlantic Coast of Morocco: LC-MS/MS and Mouse Bioassay Analyses
Provedor de dados: 5
Autores: Ben Haddouch, Asia; Amanhi, Rachid; Amzil, Zouher; Taleb, Hamib; Rovillon, Georges-augustin; Adly, Farida; Loutfi, Mohammed.
Forthe Moroccan Phycotoxins Monitoring that is part of theSafety of theCoastal Monitoring Network(RSSL),shellfish sampleswereharvestedfromdifferentlocations at NorthAtlantic of Morocco whereharmful algaeblooms were known to have occurred. Forallshellfishsamples found positive by themouse bioassay fordiarrheicshellfishpoisoning(DSP)toxins,liquid chromatography coupled to tandem massspectrometry(LC-MS-MS) in order to search thefollowinglipophilictoxins: okadaic acid (OA), dinophysistoxins(DTXs), pectenotoxins(PTXs), azaspiracids(AZAs), yessotoxins(YTXs), spirolides(SPXs) and gymnodimines (GYMs).Theresultsrevealeddifferentlipophilictoxinprofiles as a function of theshellfish sampling location. It has beennoticed that allthesamples contained OA and its...
Tipo: Text
Palavras-chave: Diarrheictoxins; Lipophilic toxins; LC-MS/MS; Mouse test; Shellfish.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00372/48342/48495.pdf

From the sxtA4 Gene to Saxitoxin Production: What Controls the Variability Among Alexandrium minutum and Alexandrium pacificum Strains?
Provedor de dados: 5
Autores: Geffroy, Solene; Lechat, Marc-marie; Le Gac, Mickael; Rovillon, Georges-augustin; Marie, Dominique; Bigeard, Estelle; Malo, Florent; Amzil, Zouher; Guillou, Laure; Caruana, Amandine.
Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of shellfish that accumulate paralytic shellfish toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis is encoded in the nuclear genome via a gene cluster (sxt). Toxin production is supposedly associated with the presence of a 4th domain in the sxtA gene (sxtA4), one of the core genes of the PST gene cluster. It is postulated that gene expression in dinoflagellates is partially constitutive, with both transcriptional and post-transcriptional processes potentially co-occurring. Therefore, gene structure and expression mode are two important features to explore in order to fully understand toxin production processes...
Tipo: Text
Palavras-chave: Alexandrium; Saxitoxins; SxtA4; Copy number variation; SxtA; Expression; Isoform.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00682/79402/81944.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

Détection de l'acide okadaïque dans les moules toxiques : comparaisons de bioéssais
Provedor de dados: 5
Autores: Marcaillou-le Baut, Claire; Masselin, Pierre; Bohec, Madeleine; Truquet, Philippe; Amzil, Zouher; Pouchus, Francois; Le Boterff, Jean; Verbist, Jean-françois; Vernoux, Jean-paul; Marais, Chantal; Simon, Jean-françois; Nizard, Gabrielle; Mercier, Géraldine; Choumiloff, Roxelan; Baron, Bruno.
Cette étude est le résultat d'un travail de trois équipes: elle porte sur la comparaison du test souris avec différents bioessais déjà pratiqués en routine dans les laboratoires participants. Ces bioessais sont : - un test sur micro crustacé dont la méthodologie est normalisée et qui est très utilisé en écotoxicologie aquatique ; - un test de cytotoxicité à court terme qui a été mis au point pour cette étude.
Tipo: Text
Ano: 1992
URL: http://archimer.ifremer.fr/doc/00139/25035/23144.pdf

Cytodétection des phycotoxines diarrhéiques - Une alternative au test de toxicité aiguë sur souris pour la surveillance de la salubrité des coquillages
Provedor de dados: 5
Autores: Amzil, Zouher.
The cytodetection test of diarrheic phycotoxin KB-cells (DRAME test) was developed to ultimately provide a substitute for the acute toxicity mouse-test currently used by IFREMER's phytoplankton monitoring network (REPHY). The cyctodetection test relies on the cell morphological changes induced by the phosphorylation of cytoskeleton proteins resulting from the inhibition of cell protein-phosphatases by okadaic-type toxins. The method is specific, sensitive and fast with results given on the same day. In addition, the method has been shown to produce a good correlation with the acute toxicity mouse-test as weil as with HPLC analyses of diarrheic phycotoxins. The cytodetection test was awarded the only Special Prize of the Jury at the 6th AMAL THEE Awards...
Tipo: Text
Palavras-chave: Acide okadaïque; Inhibition des protéines phosphatases; Cytodétection; Cellules KB; Okadaic acid; Inhibition of protein-phosphatase; Cytodeteciton KB-cells.
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00156/26730/24811.pdf

Preliminary metabolomic approach on cyanobacterial co-cultures: Chemically mediated interactions between Microcystis and Planktothrix
Provedor de dados: 5
Autores: Mondeguer, Florence; Sibat, Manoella; Reubrecht, Sébastien; Amzil, Zouher; Bormans, Myriam; Hess, Philipp; Briand, Enora.
Cyanobacterial proliferation is one of the most harmful hazards, in both freshwater and marine ecosystems. Cyanobacteria are well known for their ability to produce a wide variety of bioactive compounds, some of which have been described as allelochemicals. There is growing evidence that these secondary metabolites play an important role in shaping community composition through biotic interactions; however, for the most part, their biological role and mode of regulation of the production are poorly understood. In temperate eutrophic freshwaters, Microcystis and Planktothrix often co-occur, with Planktothrix being an early colonizer and Microcystis appearing subsequently. By integrating LC-MS/MS molecular networking and an innovative experimental design, we...
Tipo: Text
Palavras-chave: Cyanobacteria; Cyanotoxins; Plankton interactions; Co_culture; LC_HRMS; Molecular Network; Metabolomics.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00405/51666/52215.pdf

Modelling of paralytic shellfish toxin biotransformations in the course of Crassostrea gigas detoxification kinetics
Provedor de dados: 5
Autores: Gueguen, Marielle; Baron, Regis; Bardouil, Michele; Truquet, Philippe; Haberkorn, Hansy; Lassus, Patrick; Barille, Laurent; Amzil, Zouher.
The aim of this study was to evaluate the importance of biotransformation of paralytic shellfish toxins during the detoxification process in contaminated oysters. Mathematical models based upon the detoxification patterns of digestive gland and other tissues were developed. It was demonstrated that biotransformations do not seem to play an important role in digestive gland or other tissue detoxification kinetics with our data set. Moreover, different toxin transfers from digestive gland toward other tissues were investigated. No significant transfer was highlighted in our data set. These first conclusions were drawn after comparing the results obtained from 13 biotransformations and identifiable transfer scenarios. Finally, to determine a more robust...
Tipo: Text
Palavras-chave: Detoxification kinetics modelling; Biotransformation of saxitoxin analogues; Oyster.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00049/16047/14309.pdf

Chemically mediated interactions between   Microcystis   and   Planktothrix   : impact on their growth, morphology and metabolic profiles
Provedor de dados: 5
Autores: Briand, Enora; Reubrecht, Sébastien; Mondeguer, Florence; Sibat, Manoella; Hess, Philipp; Amzil, Zouher; Bormans, Myriam.
Freshwater cyanobacteria are known for their ability to produce bioactive compounds, some of which have been described as allelochemicals. Using a combined approach of co‐cultures and analyses of metabolic profiles, we investigated chemically mediated interactions between two cyanobacterial strains, Microcystis aeruginosa PCC7806 and Planktothrix agardhii PCC7805. More precisely, we evaluated changes in growth, morphology and metabolite production and release by both interacting species. Co‐culture of Microcystis with Planktothrix resulted in a reduction of the growth of Planktothrix together with a decrease of its trichome size and alterations in the morphology of its cells. The production of intracellular compounds by Planktothrix showed a slight...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00470/58152/60632.pdf

Contamination en dinophysistoxines des moules de Bretagne sud Mise en évidence des dérivés acyls-esters de l'acide okadaïque (DTX-3) Etude comparative : analyses chimiques, tests biologiques et concentrations cellulaires de Dinophysis
Provedor de dados: 5
Autores: Amzil, Zouher; Mathias, Amaury.
Ifremer monitoring network for phytoplankton and phycotoxins (REPHY) is in charge of shellfish safety control and carries out shellfish toxicity test on mice as soon as Dinophysis cells (okadaic acid "OA" producer) are observed in sea water. However, this test can neither identify or quantify the diarrhetic toxins OA and its analogues (DTX-1, DTX-3). Only a chemical analysis is able to detect them. At first, the shellfish extraction procedure used for mouse-tests was optimised in order to adjust it for OA/DTX-1 chemical analysis. Due to the Iack of standard, DTX-3 quantification is clone indirectly after a hydrolysis stage releasing OA. Chemical analysis of shellfish samples collected in 2001 from three locations of "Long-line Mussel Farming" of southern...
Tipo: Text
Palavras-chave: Acide okadaïque (AO); 7-0-acyl-AO (DTX-3); Moule; Dinophysis; Analyse chimique.; Okadaic acid (OA); 7-0-acyl-OA (DTX-3); Musset; Dinophysis; Chemical analysis.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00132/24282/22280.pdf

Molecular Characterization of Voltage-Gated Sodium Channels and Their Relations with Paralytic Shellfish Toxin Bioaccumulation in the Pacific Oyster Crassostrea gigas
Provedor de dados: 5
Autores: Boullot, Floriane; Castrec, Justine; Bidault, Adeline; Dantas, Natanael; Payton, Laura; Perrigault, Mickael; Tran, Damien; Amzil, Zouher; Boudry, Pierre; Soudant, Philippe; Hegaret, Helene; Fabioux, Caroline.
Paralytic shellfish toxins (PST) bind to voltage-gated sodium channels (Nav) and block conduction of action potential in excitable cells. This study aimed to (i) characterize Nav sequences in Crassostrea gigas and (ii) investigate a putative relation between Nav and PST-bioaccumulation in oysters. The phylogenetic analysis highlighted two types of Nav in C. gigas: a Nav1 (CgNav1) and a Nav2 (CgNav2) with sequence properties of sodium-selective and sodium/calcium-selective channels, respectively. Three alternative splice transcripts of CgNav1 named A, B and C, were characterized. The expression of CgNav1, analyzed by in situ hybridization, is specific to nervous cells and to structures corresponding to neuromuscular junctions. Real-time PCR analyses showed...
Tipo: Text
Palavras-chave: Crassostrea gigas; Sodium channel; Alternative splicing; Alexandrium minutum; Paralytic shellfish toxins.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00368/47877/47892.pdf

Tissue Distribution and Elimination of Ciguatoxins in Tridacna maxima (Tridacnidae, Bivalvia) Fed Gambierdiscus polynesiensis
Provedor de dados: 5
Autores: Roue, Melanie; Darius, Helene Taiana; Ung, Andre; Viallon, Jerome; Sibat, Manoella; Hess, Philipp; Amzil, Zouher; Chinain, Mireille.
Ciguatera is a foodborne disease caused by the consumption of seafood contaminated with ciguatoxins (CTXs). Ciguatera-like poisoning events involving giant clams (Tridacna maxima) are reported occasionally from Pacific islands communities. The present study aimed at providing insights into CTXs tissue distribution and detoxification rate in giant clams exposed to toxic cells of Gambierdiscus polynesiensis, in the framework of seafood safety assessment. In a first experiment, three groups of tissue (viscera, flesh and mantle) were dissected from exposed individuals, and analyzed for their toxicity using the neuroblastoma cell-based assay (CBA-N2a) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses. The viscera, flesh, and mantle were...
Tipo: Text
Palavras-chave: Giant clams; Ex situ exposure to toxic algae; Ciguatoxins; Gambierdiscus polynesiensis; Anatomical distribution; Toxin elimination; CBA-N2a; LC-MS/MS.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00440/55123/56579.pdf

Bilan des résultats du dispositif de vigilance pour les phycotoxines lipophiles - Année 2015
Provedor de dados: 5
Autores: Neaud-masson, Nadine; Amzil, Zouher.
L’Ifremer est chargé d’apporter à l’État et aux autres personnes morales de droit public son concours pour l’exercice de leurs responsabilités notamment pour le contrôle de la qualité des produits de la mer et du milieu marin. La mise en œuvre d’un Réseau d'Observation et de Surveillance du Phytoplancton et des Phycotoxines (REPHY) depuis sa création en 1984, répond à cette mission et le concours apporté à l’Administration Centrale se concrétise en un soutien aux autorités publiques dont la Direction Générale de l’Alimentation (DGAL) du Ministère de l’Agriculture, de l’Agroalimentaire et de la Forêt (MAAF), pour ce qui concerne l’application de la réglementation relative au suivi de la salubrité des zones de production de coquillages. Un changement majeur...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00341/45243/44678.pdf

Tectus niloticus (Tegulidae, Gastropod) as a Novel Vector of Ciguatera Poisoning: Detection of Pacific Ciguatoxins in Toxic Samples from Nuku Hiva Island (French Polynesia)
Provedor de dados: 5
Autores: Darius, Helene Taiana; Roue, Melanie; Sibat, Manoella; Viallon, Jerome; Gatti, Clemence Mahana Iti; Vandersea, Mark W.; Tester, Patricia A.; Litaker, R. Wayne; Amzil, Zouher; Hess, Philipp; Chinain, Mireille.
Ciguatera fish poisoning (CFP) is a foodborne disease caused by the consumption of seafood (fish and marine invertebrates) contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the genus Gambierdiscus. The report of a CFP-like mass-poisoning outbreak following the consumption of Tectus niloticus (Tegulidae, Gastropod) from Anaho Bay on Nuku Hiva Island (Marquesas archipelago, French Polynesia) prompted field investigations to assess the presence of CTXs in T. niloticus. Samples were collected from Anaho Bay, 1, 6 and 28 months after this poisoning outbreak, as well as in Taiohae and Taipivai bays. Toxicity analysis using the neuroblastoma cell-based assay (CBA-N2a) detected the presence of CTXs only in Anaho Bay T. niloticus samples. This is...
Tipo: Text
Palavras-chave: Ciguatera poisoning; Ciguatoxins; Tectus niloticus; Gastropods; Gambierdiscus polynesiensis; QPCR assays; CBA-N2a; LC-MS; MS.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00426/53798/54719.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

Effects of copper and butyltin compounds on the growth, photosynthetic activity and toxin production of two HAB dinoflagellates : the planktonic Alexandrium catenella and the benthic Ostreopsis cf. ovata
Provedor de dados: 5
Autores: Couet, Douglas; Pringault, Olivier; Bancon-montigny, Chrystelle; Briant, Nicolas; Poulichet, Francoise Elbaz; Delpoux, Sophie; Yahia, Ons Kefi-daly; Hela, Bengharbia; Charaf, M'Rabet; Herve, Fabienne; Rovillon, Georges-augustin; Amzil, Zouher; Laabir, Mohamed.
Controlled laboratory experiments were conducted to test the effects of copper (Cu2+) and butyltins (BuT) on the growth, photosynthetic activity and toxin content of two HABs (Harmful Algal Blooms) dinoflagellates, the planktonic Alexandrium catenella and the benthic Ostreopsis cf. ovata. Microalgae were exposed to increasing concentrations of Cu2+ (10−4 to 31 nM) or BuT (0.084 to 84 nM) for seven days. When considering the growth, EC50 values were 0.16 (±0.09) nM and 0.03 (±0.02) nM of Cu2+ for A. catenella and O. cf. ovata, respectively. Regarding BuT, EC50 was 14.2 (±6) nM for O. cf. ovata, while A. catenella growth inhibition appeared at BuT concentrations ≥27 nM. Photosynthetic activity of the studied dinoflagellates decreased with increasing Cu and...
Tipo: Text
Palavras-chave: Alexandrium catenella; Ostreopsis cf. ovata; Cu; Butyltin; Photosynthesis; Toxins.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00418/52970/53896.pdf

Etude sur la prolifération de la micro algue Alexandrium minutum en rade de Brest. Projet Daoulex. Rapport d’avancement n° 1 : Novembre 2013
Provedor de dados: 5
Autores: Chapelle, Annie; Le Bec, Claude; Le Gac, Mickael; Labry, Claire; Amzil, Zouher; Guillou, Laure; Dreanno, Catherine; Pineau-guillou, Lucia.
Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été monté avec la Région dans le cadre du développement du port de Brest. De juillet à août 2013, l’Ifremer a organisé un échantillonnage serré dans l’estuaire de Daoulas, zone la plus touchée en 2012. De ce suivi et des mesures réalisées au laboratoire à ce jour, ainsi que des résultats du réseau Rephy et Velyger, il ressort que : * Alexandrium minutum s’est développé à nouveau en rade de Brest en 2013 mais à des teneurs inférieures à 2012. * l’épisode de bloom et de toxicité supérieur aux seuils légaux s’est déroulé plus tard qu’en 2012, du 1er juillet jusqu’à 5 août. * les efflorescences et la toxicité ont touché...
Tipo: Text
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00191/30230/28644.pdf

Projet de recherche sur l'identification de nouveaux composés toxiques dans les coquillages
Provedor de dados: 5
Autores: Amzil, Zouher.
ln November 1992, an event affecting Shellfish health received extensive media coverage: an unknown toxin had been detected in oysters from the bay of MarennesOleron (France). This phenomenon remains unexplained to this day. Since then, a growing number of observations obtained in the context of the REPHY phytoplankton monitoring network, have reported a mouse-active substance found in Shellfish and belonging to none of the known phycotoxin classes. These observations have been reported in France as weil as abroad (Canada, Norway, Ireland, New Zealand ... ). Mice treated intraperitoneally with the DSP screening test- exhibit neurological symptoms with disorders of the central nervous system leading to early death (within 5 to 10 minutes). Several hundred...
Tipo: Text
Palavras-chave: Toxicité atypique; Test-souris; Neurotoxicité; Identification de principe(s) actif(s); Atypical toxicity; Mouse-test; Neurotoxicity; Identification of active principle( s).
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00156/26732/24813.pdf

New insights on the species-specific allelopathic interactions between macrophytes and marine HAB dinoflagellates
Provedor de dados: 5
Autores: Ben Gharbia, Hela; Yahia, Ons Kefi-daly; Cecchi, Philippe; Masseret, Estelle; Amzil, Zouher; Herve, Fabienne; Rovillon, Georges-augustin; Nouri, Habiba; M'Rabet, Charaf; Couet, Douglas; Triki, Habiba Zmerli; Laabir, Mohamed.
Macrophytes are known to release allelochemicals that have the ability to inhibit the proliferation of their competitors. Here, we investigated the effects of the fresh leaves of two magnoliophytes (Zostera noltei and Cymodocea nodosa) and thalli of the macroalgae Ulva rigida on three HAB-forming benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima, and Coolia monotis). The effects of C. nodosa and U. rigida were also tested against the neurotoxic planktonic dinoflagellate Alexandrium pacificum Litaker sp. nov (former Alexandrium catenella). Co-culture experiments were conducted under controlled laboratory conditions and potential allelopathic effects of the macrophytes on the growth, photosynthesis and toxin production of the targeted...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00411/52200/52917.pdf

Ostreopsis lenticularis Y. Fukuyo (Dinophyceae, Gonyaulacales) from French Polynesia (South Pacific Ocean): A revisit of its morphology, molecular phylogeny and toxicity
Provedor de dados: 5
Autores: Chomérat, Nicolas; Bilien, Gwenael; Derrien, Amelie; Henry, Kévin; Ung, André; Viallon, Jérôme; Darius, Hélène Taiana; Mahana Iti Gatti, Clémence; Roué, Mélanie; Hervé, Fabienne; Réveillon, Damien; Amzil, Zouher; Chinain, Mireille.
To date, the genus Ostreopsis comprises eleven described species, of which seven are toxigenic and produce various compounds presenting a major threat to human and environmental health. The taxonomy of several of these species however remains controversial, as it was based mostly on morphological descriptions leading, in some cases, to ambiguous interpretations and even possible misidentifications. The species Ostreopsis lenticularis was first described by Y. Fukuyo from French Polynesia using light microscopy observations, but without genetic information associated. The present study aims at revisiting the morphology, molecular phylogeny and toxicity of O. lenticularis based on the analysis of 47 strains isolated from 4 distinct locales of French...
Tipo: Text
Palavras-chave: ITS-5.8S rDNA; LSU rDNA; Microscopy; Ostreopsis lenticularis; Taxonomy; Toxins.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00486/59747/62887.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

Bassins insubmersibles et contamination par les micro-algues toxiques (BICMAT)
Provedor de dados: 5
Autores: Derrien, Amelie; Terre Terrillon, Aouregan; Duval, Audrey; Lebrun, Luc; Doner, Anne; Rovillon, Georges-augustin; Amzil, Zouher; Le Bec, Claude.
En cas de fermeture de zone de production pour cause de présence d'une espèce de micro algues toxique, une mesure prévoit pour les professionnels de la conchyliculture l'interdiction générale d'utilisation de l'eau de mer déjà pompée dans un bassin insubmersible. C'est dans ce contexte que la DGAL a sollicité l'appui du LER BO pour la mise en place d'une étude dans des conditions professionnelles. Cette étude vise à déterminer d'il existe un risque de contamination lors de l'immersion de coquillages non contaminés dans un bassun insubmersible rempli en eau de mer pompée dans une zone fermée pour cause de présence de micro-algues toxiques. Entre fin juin et début juillet, la présence de Dinophysis sp a entraîné la fermeture de la baie de Concarneau. Des...
Tipo: Text
Palavras-chave: Dinophysis; Toxines lipophiles; Acide okadaïque; Yessotoxines; Bassin insubmersible; Huîtres; Moules.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00486/59736/62831.pdf

Direct evidence for toxin production by   Pseudo-nitzschia plurisecta   (Bacillariophyceae) and extension of its distribution area
Provedor de dados: 5
Autores: Caruana, Amandine; Ayache, Nour; Raimbault, Virginie; Rétho, Michael; Hervé, Fabienne; Bilien, Gwenael; Amzil, Zouher; Chomérat, Nicolas.
We confirm an amnesic shellfish poisoning risk associated with domoic acid production by the species Pseudo-nitzschia plurisecta and determine the toxin profile, which includes three domoic acid isomers. Although the species was reported once in European waters, along the Spanish Atlantic coast, here we describe and characterize P. plurisecta collected during the first occurrence in French Atlantic waters. Three strains (IFR-PPL-15.1, 15.2 and 15.3) were isolated from French coastal water samples in June 2015. These strains were identified and characterized by microscopic observation, molecular (ITS region sequencing and phylogenetic analysis) and metabolite (toxins and pigments) analyses. The cell shape is lanceolate and the valve contains a central...
Tipo: Text
Palavras-chave: Coastal monitoring; Domoic acid; Pigment composition; Pseudo-nitzschia plurisecta; Taxonomic identification; Toxic diatoms.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00505/61687/66033.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

Cyanobactéries dans le Lac d’Hossegor en 2013
Provedor de dados: 5
Autores: Rumebe, Myriam; Auby, Isabelle; Chomerat, Nicolas; Amzil, Zouher; Costa, Magali; Arrue, François.
Cette note concerne une efflorescence de cyanobactéries du genre Planktothrix dans le Lac marin d'Hossegor, en janvier 2013. La provenance de ces microalgues a été identifiée et leur innocuité démontrée grâce aux résultats d'analyses des phycotoxines.
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00167/27834/26040.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

Influence of sudden salinity variation on the physiology and domoic acid production by two strains of   Pseudo-nitzschia australis
Provedor de dados: 5
Autores: Ayache, Nour; Hervé, Fabienne; Martin-jézéquel, Veronique; Amzil, Zouher; Caruana, Amandine.
Several coastal countries including France have experienced serious and increasing problems related to Pseudo‐nitzschia toxic blooms. These toxic blooms occur in estuarine and coastal waters potentially subject to fluctuations in salinity. In this study, we document for the first time the viability, growth, photosynthetic efficiency and toxin production of two strains of Pseudo‐nitzschia australis grown under conditions with sudden salinity changes. Following salinity variation, the two strains survived over a restricted salinity range of 30 to 35, with favorable physiological responses, as the growth, effective quantum yield and toxin content were high compared to the other conditions. In addition, high cellular quotas of domoic acid (DA) were observed at...
Tipo: Text
Palavras-chave: Amnesic shellfish poisoning; Domoic acid; Harmful algae; Pseudo-nitzschia australis; Salinity stress.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00462/57385/59465.pdf

Phycotoxin monitoring in France : risk-based strategy and main results (2006-2008)
Provedor de dados: 5
Autores: Belin, Catherine; Amzil, Zouher.
Toxin monitoring is carried out along the coasts of France by a national network, REPHY, which is the National Monitoring Network for Phytoplankton and Phycotoxins. Sampling strategy differs according to the type of zone coastal or offshore and to the family of toxins. For PSP and ASP toxins, monitoring is based on the detection of toxic phytoplankton species. For lipophilic toxins, a systematic analysis of toxins is performed in risk areas during high risk periods. Experimental monitoring for palytoxins has also been conducted along the Mediterranean coast since 2007. The total number of toxin analyses is in the order of 2500 to 3000 per year. The detailed results for each family of toxins showed that the most frequent toxic events for the period from...
Tipo: Text
Palavras-chave: Monitoring; Phytoplankton; Toxin; Sampling; Shellfish; French coasts.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00077/18821/16398.pdf

Salt Shock Responses of Microcystis Revealed through Physiological, Transcript, and Metabolomic Analyses
Provedor de dados: 5
Autores: Georges Des Aulnois, Maxime; Réveillon, Damien; Robert, Elise; Caruana, Amandine; Briand, Enora; Guljamow, Arthur; Dittmann, Elke; Amzil, Zouher; Bormans, Myriam.
The transfer of Microcystis aeruginosa from freshwater to estuaries has been described worldwide and salinity is reported as the main factor controlling the expansion of M. aeruginosa to coastal environments. Analyzing the expression levels of targeted genes and employing both targeted and non-targeted metabolomic approaches, this study investigated the e ect of a sudden salt increase on the physiological and metabolic responses of two toxic M. aeruginosa strains separately isolated from fresh and brackish waters, respectively, PCC 7820 and 7806. Supported by di erences in gene expressions and metabolic profiles, salt tolerance was found to be strain specific. An increase in salinity decreased the growth of M. aeruginosa with a lesser impact on the...
Tipo: Text
Palavras-chave: Microcystis aeruginosa; Microcystin; Salt stress; Metabolomic; Transcript.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00615/72689/71692.pdf

COMSAUMOL (maintien de la COMmercialisation par la SAUvegarde et la détoxication des MOLlusques). Etude 2008-2010. Rapport final
Provedor de dados: 5
Autores: Haure, Joel; Hussenot, Jerome; Buzin, Florence; Dupuy, Beatrice; Palvadeau, Hubert; Penisson, Christian; Papin, Mathias; Nourry, Max; Lassus, Patrick; Marcaillou-le Baut, Claire; Mondeguer, Florence; Royer, F.; Amzil, Zouher; Belin, Catherine; Cardinal, Mireille; Le Grel, L.; Le Bihan, V.; Jaouen, P.; Massé, A.; Castaing, Jean-baptiste; Sabiri, Ne.; Pontié, M.
La contamination des denrées d’origine marine par des toxines algales (phycotoxines) a pris depuis quelques années une importance considérable. Ce phénomène est largement lié à l’augmentation du nombre de zones géographiques touchées ainsi qu’à la diversification des espèces toxinogènes et à l’identification de nouveaux composés toxiques. Les données épidémiologiques sont cependant encore peu nombreuses car elles sont liées à la mise en place de contrôles systématiques récents. L’Union Européenne a établi un Laboratoire Communautaire de référence pour les phycotoxines, situé à Vigo (Espagne) qui coordonne les activités des laboratoires Nationaux de références correspondants (en France c’est le LNR Phycotoxines de l’AFSSA qui assure cette mission). C’est...
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00092/20277/17922.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

Toxin content of Ostreopsis cf. ovata depends on bloom phases, depth and macroalgal substrate in the NW Mediterranean Sea
Provedor de dados: 5
Autores: Gémin, Marin-pierre; Réveillon, Damien; Hervé, Fabienne; Pavaux, Anne-sophie; Tharaud, Maxime; Séchet, Veronique; Bertrand, Samuel; Lemée, Rodolphe; Amzil, Zouher.
Over the last fifteen years, blooms of the genus Ostreopsis have been reported more frequently and at higher abundances in the Mediterranean area. Ostreopsis cf. ovata is known to produce ovatoxins (OVTXs), structural analogues of palytoxin, which is one of the most potent non-polymeric toxins. However, the production of OVTXs is poorly characterized in situ. The present study focuses on toxin content and profile according to the bloom phase during summer 2017 in Villefranche-sur-Mer, France (NW Mediterranean Sea), depth (from 0.5 to 5 m) and three different macroalgal substrates of this epiphytic dinoflagellate (Padina pavonica, Dictyota spp. and Halopteris scoparia). Ovatoxin quantification of all samples was performed by liquid chromatography coupled to...
Tipo: Text
Palavras-chave: Dinoflagellate; Benthic HABs; Ostreopsis cf. ovata; Ovatoxins; Mediterranean Sea.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00614/72566/74835.pdf

Exposure to toxic Alexandrium minutum activates the detoxifying and antioxidant systems in gills of the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Fabioux, Caroline; Sulistiyani, Yeni; Haberkorn, Hansy; Hegaret, Helene; Amzil, Zouher; Soudant, Philippe.
Harmful algal blooms of Alexandrium spp. dinoflagellates regularly occur in French coastal waters contaminating shellfish. Studies have demonstrated that toxic Alexandrium spp. disrupt behavioural and physiological processes in marine filter-feeders, but molecular modifications triggered by phycotoxins are less well understood. This study analyzed the mRNA levels of 7 genes encoding antioxidant/detoxifying enzymes in gills of Pacific oysters (Crassostrea gigas) exposed to a cultured, toxic strain of A. minutum, a producer of paralytic shellfish toxins (PST) or fed Tisochrysis lutea (T. lutea, formerly Isochrysis sp., clone Tahitian (T. iso)), a non-toxic control diet, in four repeated experiments. Transcript levels of sigma-class glutathione S-transferase...
Tipo: Text
Palavras-chave: Crassostrea gigas; Alexandrium minutum; Paralytic shellfish toxins; Antioxidant enzymes; Detoxification enzymes; MRNA.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00275/38601/38623.pdf

Paralytic Toxins Accumulation and Tissue Expression of alpha-Amylase and Lipase Genes in the Pacific Oyster Crassostrea gigas Fed with the Neurotoxic Dinoflagellate Alexandrium catenella
Provedor de dados: 5
Autores: Rolland, Jean-luc; Pelletier, Kevin; Masseret, Estelle; Rieuvilleneuve, Fabien; Savar, Veronique; Santini, Adrien; Amzil, Zouher.
The pacific oyster Crassostrea gigas was experimentally exposed to the neurotoxic Alexandrium catenella and a non-producer of PSTs, Alexandrium tamarense (control algae), at concentrations corresponding to those observed during the blooming period. At fixed time intervals, from 0 to 48 h, we determined the clearance rate, the total filtered cells, the composition of the fecal ribbons, the profile of the PSP toxins and the variation of the expression of two a-amylase and triacylglecerol lipase precursor (TLP) genes through semi-quantitative RT-PCR. The results showed a significant decrease of the clearance rate of C. gigas fed with both Alexandrium species. However, from 29 to 48 h, the clearance rate and cell filtration activity increased only in oysters...
Tipo: Text
Palavras-chave: Crassostrea gigas; Alexandrium catenella; PSP toxins; Digestion; Gene expression.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00130/24170/22172.pdf

COSELMAR. Compréhension des socio-écosystèmes littoraux et marins pour la prévention et la gestion des risques. Bilan scientifique 2013-2017
Provedor de dados: 5
Autores: Pardo, Sophie; Hess, Philipp; Simon, Elodie; Barille, Laurent; Geslin, Emmanuelle; Cognie, Bruno; Martin-jezequel, Véronique; Sechet, Véronique; Herrenknecht, Christine; Baron, Regis; Bourseau, Patrick; Amzil, Zouher; Masse, Anthony; Vandanjon, Laurent; Dumay, Justine; Lebeau, Thierry; Turpin, Vincent; Mondeguer, Florence; Petitgas, Pierre; Trouillet, Brice; Mercier, Denis; Guillotreau, Patrice; Guineberteau, Thierry; Mahevas, Stephanie; Schoefs, Franck; Sophie Pardo; Philipp Hess; Pauline Borgniet; Laurent Barillé; Emmanuelle Geslin; Bruno Cognie; Véronique Martin-Jezequel; Véronique Sechet; Christine Herrenknecht; Régis Baron; Patrick Bourseau; Zouher Amzil; Anthony Massé; Laurent Vandanjon; Justine Dumay; Thierry Lebeau; Vincent Turpin; Florence Mondeguer; Pierre Petitgas; Brice Trouillet.
COSELMAR, a 4-year project financed by the Région des Pays de la Loire at 2.1 M€, officially started on the 7th January 2013. The project is coordinated by Philipp Hess (IFREMER) and Sophie Pardo (Université de Nantes-LEMNA) and falls under the Federation for Research Institut Universitaire Mer et Littoral (IUML, FR CNRS 3473)*. COSELMAR has also been approved by the Scientific Council of the MSH Ange Guépin. COSELMAR is a research project uniting 5 research units of IFREMER and 11 laboratories of the Université de Nantes, along with academic partners, and national and international industries. The aim is to achieve a better understanding of the marine and coastal ecosystems and the associated resources. The project will also provide insights into risk...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00406/51793/52550.pdf

Modelling paralytic shellfish toxins (PST) accumulation in Crassostrea gigas by using Dynamic Energy Budgets (DEB)
Provedor de dados: 5
Autores: Pousse, Emilien; Flye-sainte-marie, Jonathan; Alunno-bruscia, Marianne; Hegaret, Helene; Rannou, Eric; Pecquerie, Laure; Marques, Goncalo M.; Thomas, Yoann; Castrec, Justine; Fabioux, Caroline; Long, Marc; Lassudrie, Malwenn; Hermabessiere, Ludovic; Amzil, Zouher; Soudant, Philippe; Jean, Fred.
As other filter-feeders, Crassostrea gigas can concentrate paralytic shellfish toxins (PST) by consuming dinoflagellate phytoplankton species like Alexandrium minutum. Intake of PST in oyster tissues mainly results from feeding processes, i.e. clearance rate, pre-ingestive sorting and ingestion that are directly influenced by environmental conditions (trophic sources, temperature). This study aimed to develop a mechanistic model coupling the kinetics of PST accumulation and bioenergetics in C. gigas based on Dynamic Energy Budget (DEB) theory. For the first time, the Synthesizing Units (SU) concept was applied to formalize the feeding preference of oysters between non-toxic and toxic microalgae. Toxin intake and accumulation were both dependent on the...
Tipo: Text
Palavras-chave: Alexandrium minutum; Paralytic shellfish toxins (PST); Dynamic Energy Budget (DEB); Modelling; Pacific oyster.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00455/56662/58407.pdf

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

Surveillance des toxines lipophiles dans les coquillages. Ananlyse statistique et comparaison des résultats obtenus par deux méthodes d'analyse : les bio-essais sur souris et les analyses chimiques par CL-SM/SM
Provedor de dados: 5
Autores: Belin, Catherine; Soudant, Dominique; Amzil, Zouher.
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00014/12568/9438.pdf

Toxicity and Growth Assessments of Three Thermophilic Benthic Dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) Developing in the Southern Mediterranean Basin
Provedor de dados: 5
Autores: Ben-gharbia, Hela; Yahia, Ons Kefi-daly; Amzil, Zouher; Chomerat, Nicolas; Abadie, Eric; Masseret, Estelle; Sibat, Manoella; Triki, Habiba Zmerli; Nouri, Habiba; Laabir, Mohamed.
armful benthic dinoflagellates, usually developing in tropical areas, are expanding to temperate ecosystems facing water warming. Reports on harmful benthic species are particularly scarce in the Southern Mediterranean Sea. For the first time, three thermophilic benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) were isolated from Bizerte Bay (Tunisia, Mediterranean) and monoclonal cultures established. The ribotyping confirmed the morphological identification of the three species. Maximum growth rates were 0.59 ± 0.08 d−1 for O. cf. ovata, 0.35 ± 0.01 d−1 for C. monotis and 0.33 ± 0.04 d−1 for P. lima. Toxin analyses revealed the presence of ovatoxin-a and ovatoxin-b in O. cf. ovata cells. Okadaic acid and...
Tipo: Text
Palavras-chave: Ostreopsis cf. ovata; Prorocentrum lima; Coolia monotis; Southern Mediterranean Sea; Growth; Toxicity.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00355/46585/46393.pdf

Detoxification enhancement in the gymnodimine-contaminated grooved carpet shell, Ruditapes decussatus (Linne)
Provedor de dados: 5
Autores: Medhioub, Walid; Gueguen, Marielle; Lassus, Patrick; Bardouil, Michele; Truquet, Philippe; Sibat, Manoella; Nejib, Medhioub; Philippe, Soudant; Mejdeddine, Kraiem; Amzil, Zouher.
In the Gulf of Gabes (Tunisia, Eastern Mediterranean sea), the grooved carpet shell Ruditapes decussatus has been seen to contain persistent levels of gymnodimine (GYM) for several years. The present experimental work represents the first attempt to assess detoxification kinetics of fast-acting toxins (FAT) in marine molluscs fed specific diets of non-toxic algae (Isochrysis galbana). To find an optimal detoxification method, two experiments were performed in which clams were first fed the toxic dinoflagellate Karenia selliformis to artificially contaminate them with GYM, thus simulating the effect of natural toxic episodes. As a second step, the same clams were fed a non-toxic algae, I. galbana. to speed up the detoxification process. Changes in toxin...
Tipo: Text
Palavras-chave: Ruditapes decussates; Grooved carpet shell; Karenia selliformis; Gymnodimine; Toxicity; Detoxification.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/2010/publication-7488.pdf

Influence of environmental parameters on Karenia selliformis toxin content in culture
Provedor de dados: 5
Autores: Medhioub, Amel; Medhioub, Walid; Amzil, Zouher; Sibat, Manoella; Bardouil, Michele; Ben Neila, Idriss; Mezghani, Salah; Hamza, Asma; Lassus, Patrick.
Karenia selliformis strain GM94GAB was isolated in 1994 from the north of Sfax, Gabes gulf, Tunisia. This species, which produces gymnodimine (GYM) a cyclic imine, has since been responsible for chronic contamination of Tunisian clams. A study was made by culturing the microalgae oil enriched Gaillard f/2 medium. The influence of growing conditions oil toxin content was studied, examining the effects of (i) different culture Volumes (0.25 to 40 litre flasks), (ii) two temperature ranges (17-15 degrees C et 20-21 degrees C) and (iii) two salinities (36 and 44). Chemical analyses were made by mass spectrometry coupled with liquid chromatography (LC-MS/MS). Results showed that (i) the highest growth rate (0.34 +/- 0.14 div d(-1)) was obtained at 20 degrees C...
Tipo: Text
Palavras-chave: Mouse bioassay; Gymnodimine; Toxicity; Growth; Karenia selliformis.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-7383.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

First report on azaspiracid and yessotoxin groups detection in French shellfish
Provedor de dados: 5
Autores: Amzil, Zouher; Sibat, Manoella; Royer, Florence; Savar, Veronique.
The French Phytoplankton and Phycotoxins monitoring network (REPHY) recently found positive or dubious negative shellfish samples using lipophilic toxins mouse bioassay. These samples were analyzed by liquid chromatography (LC) in combination with mass spectrometry (MS) to detect the following toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs), yessotoxins (YTXs), spirolides (SPXs) and gymnodimines (GYMs). Over the 2006-2007 period, chemical analyses revealed various lipophilic toxin profiles according to shellfish sampling locations. In addition to OA and/or PTX-2 and their derivatives, several other compounds were found for the first time in France: (1) during the summer of 2006, AZA-1 and AZA-2 in Queen...
Tipo: Text
Palavras-chave: LC MS/MS analyses; Shellfish; Yessotoxin group; Azaspiracid group; Lipophilic toxins.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4560.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

Detoxification of Pacific oyster Crassostrea gigas fed on diets of Skeletonema costatum with and without silt, following PSP contamination by Alexandrium minutum
Provedor de dados: 5
Autores: Gueguen, Marielle; Bardouil, Michele; Baron, Regis; Lassus, Patrick; Truquet, Philippe; Massardier, Julie; Amzil, Zouher.
Contamination of shellfish by paralytic shellfish poisoning ( PSP) toxins poses an economic threat to shellfish farmers. As contaminated shellfish cannot be harvested for long periods of time, it would be very useful to develop processes to optimise and shorten their detoxification. In this study, Pacific oysters Crassostrea gigas were first experimentally contaminated over a period of 13 days with a continuous flow of toxic Alexandrium minutum cultures at concentrations ranging from 150 to 200 cell ml(-1) ( toxin content after 13 days of contamination 438 mu g STX equiv. 100 g(-1) wet weight). Then, two different detoxification treatments were tested and showed detoxification rates greater than those observed in coastal environments. The first treatment...
Tipo: Text
Palavras-chave: Alexandrium minutum; Crassostrea gigas; Detoxification; Inorganic matter; Organic matter; PSP; Paralytic shellfish poisoning.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-3896.pdf

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

First report on amnesic and diarrhetic toxins detection in French scallops during 2004-05 monitoring surveys
Provedor de dados: 5
Autores: Amzil, Zouher; Royer, Florence; Sibat, Manoella; Fiant, Liliane; Gelin, Muriel; Le Gal, Dominique; Francoise, Sylvaine.
In the context of the French phytoplankton and phycotoxins monitoring network (REPHY), shellfish scallops were harvested systematically during the authorised fishing season for the purpose of investigating paralytic toxins (PSP-mouse test), amnesic toxins (ASPchemical analysis), and lipophilic toxins (DSP-mouse test). For all shellfish samples that tested positive in the DSP mouse bioassay used for lipophilic toxins detection, liquid chromatography coupled with mass spectrometry (LC-MS/MS) was used to search for the following lipophilic toxins: okadaic acid, dinophysistoxins, pectenotoxins, azaspiracids, yessotoxins, spirolides, and gymnodimine. In order to investigate the presence of okadaic acid esters (DTX3), alkaline hydrolysis was performed on all...
Tipo: Text
Palavras-chave: Scallops; Domoic acid; Okadaic acid and derivatives; Dinophysis.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00015/12577/9447.pdf

Étude sur la prolifération de la micro algue Alexandrium minutum en rade de Brest
Provedor de dados: 5
Autores: Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes.
Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf

Evidence of the bioaccumulation of ciguatoxins in giant clams (Tridacna maxima) exposed to Gambierdiscus spp. cells
Provedor de dados: 5
Autores: Roue, Melanie; Darius, Helene Taiana; Picot, Sandy; Ung, Andre; Viallon, Jerome; Gaertner-mazouni, Nabila; Sibat, Manoella; Amzil, Zouher; Chinain, Mireille.
Ciguatera Fish Poisoning (CFP) is a foodborne disease classically related to the consumption of tropical coral reef fishes contaminated with ciguatoxins (CTXs), neurotoxins produced by dinoflagellates of the Gambierdiscus genus. Severe atypical ciguatera-like incidents involving giant clams, a marine resource highly consumed in the South Pacific, are also frequently reported in many Pacific Islands Countries and Territories. The present study was designed to assess the ability of giant clams to accumulate CTXs in their tissues and highlight the potential health risks associated with their consumption. Since giant clams are likely to be exposed to both free-swimming Gambierdiscus cells and dissolved CTXs in natural environment, ex situ contamination...
Tipo: Text
Palavras-chave: Giant clams; Ex situ contamination; Ciguatoxins; Gambierdiscus polynesiensis; LC-MS/MS; Neuroblastoma cell-based assay.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00343/45415/45123.pdf

Physiological and Metabolic Responses of Freshwater and Brackish-Water Strains of   Microcystis aeruginosa   Acclimated to a Salinity Gradient: Insight into Salt Tolerance
Provedor de dados: 5
Autores: Georges Des Aulnois, Maxime; Roux, Pauline; Caruana, Amandine; Réveillon, Damien; Briand, Enora; Hervé, Fabienne; Savar, Veronique; Bormans, Myriam; Amzil, Zouher; Atomi, Haruyuki.
Proliferation of microcystin (MC)-producing Microcystis aeruginosa in brackish waters has been described in several locations and represents a new concern for public and environmental health. While the impact of a sudden salinity increase on M. aeruginosa physiology has been studied, less is known about the mechanisms involved in salt tolerance after acclimation. This study aims to compare the physiological responses of two strains of M. aeruginosa (PCC 7820 and PCC 7806), which were isolated from contrasted environments, to increasing salinities. After acclimation, growth and MC production rates were determined and metabolomic analyses were conducted. For both strains, salinity decreased the biovolume, growth, and MC production rates and induced the...
Tipo: Text
Palavras-chave: Acclimation; Metabolomic; Microcystis; Salinity; Sucrose; Trehalose; Ecophysiology.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00588/70031/68012.pdf