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Registros recuperados: 7
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A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum ArchiMer
Long, Marc; Tallec, Kevin; Soudant, Philippe; Lambert, Christophe; Le Grand, Fabienne; Sarthou, Geraldine; Jolley, Dianne; Hegaret, Helene.
Harmful microalgal blooms are a threat to aquatic organisms, ecosystems and human health. Toxic dinoflagellates of the genus Alexandrium are known to produce paralytic shellfish toxins and to release bioactive extracellular compounds (BECs) with potent cytotoxic, hemolytic, ichtyotoxic and allelopathic activity. Negative allelochemical interactions refer to the chemicals that are released by the genus Alexandrium and that induce adverse effects on the physiology of co-occurring protists and predators. Releasing BECs gives the donor a competitive advantage that may help to form dense toxic blooms of phytoplankton. However BECs released by Alexandrium minutum are uncharacterized and it is impossible to quantify them using classical chemical methods....
Tipo: Text Palavras-chave: Harmful algal bloom; Alexandrium; Allelopathy; Cytotoxicity; PAM fluorometry; Bioassay.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00453/56424/58116.pdf
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Allelochemicals from Alexandrium minutum induce rapid inhibition of metabolism and modify the membranes from Chaetoceros muelleri ArchiMer
Long, Marc; Tallec, Kevin; Soudant, Philippe; Le Grand, Fabienne; Donval, Anne; Lambert, Christophe; Sarthou, Geraldine; Jolley, Dianne F.; Hegaret, Helene.
Allelochemical interactions are likely to be a contributing factor explaining the success of large blooms of the harmful marine dinoflagellate Alexandrium, however, the physiological mechanisms of allelochemical interactions remain poorly described. Here we investigated the sub-lethal effects (on an hourly scale) of a filtrate containing allelochemicals from Alexandrium minutum on the physiology of the common diatom Chaetoceros muelleri. The filtrate induced deleterious effects to the diatom physiology within only 30 min of exposure. Esterase activity and photosynthesis were drastically inhibited, with up to 34% of the population being metabolically inactive and up to 30% reduction in photosystem II quantum yield when exposed to the filtrate. In addition,...
Tipo: Text Palavras-chave: Allelopathy; Alexandrium; Metabolism; Photoinhibition; Lipids; Pigments.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00460/57133/59748.pdf
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Effects of growth phase and nitrogen limitation on biochemical composition of two strains of Tisochrysis lutea ArchiMer
Da Costa, Fiz; Le Grand, Fabienne; Quere, Claudie; Bougaran, Gael; Cadoret, Jean-paul; Robert, Rene; Soudant, Philippe.
Standard and mutant Tisochrysis lutea strains were grown in batch culture for 10 days under nitrogen (N)-replete and N-reduced conditions to determine the effects of N supply in culture medium and growth phase on microalgal physiology and biochemistry. These two T. lutea strains were compared in terms of growth, morphology, associated free-living bacterial community, viability, intracellular lipid content (as measured by Bodipy staining), chlorophyll autofluorescence, and biochemical composition, with a focus on lipid class and fatty acid compositions. The standard strain (T) reached higher cell counts regardless of N supply in culture medium. In both T. lutea strains, microalgal final cell density was significantly lower in N-reduced medium. Carbohydrates...
Tipo: Text Palavras-chave: Tisochrysis lutea; Nitrogen limitation; Growth phase; Flow cytometry; Fatty acids; Lipid classes.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00399/51074/51936.pdf
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New insights into the seasonal feeding ecology of Pecten maximus using pigments, fatty acids and sterols analyses ArchiMer
Lavaud, Romain; Artigaud, Sebastien; Le Grand, Fabienne; Donval, Anne; Soudant, Philippe; Flye-sainte-marie, Jonathan; Strohmeier, Tore; Strand, Oivind; Leynaert, Aude; Beker, Beatriz; Chatterjee, Arnab; Jean, Fred.
We combined the use of pigments, fatty acids and sterols as biomarkers of the seasonal variation in food sources of the great scallop Pecten maximus. From March to October 2011, on a biweekly to twice-weekly basis, scallops and seawater from the water column and the water-sediment interface were collected in the Bay of Brest (Brittany, France). Pigment compositions in the seawater and in the stomach and rectum content of the scallops were analyzed by HPLC. Fatty acids and sterols from digestive gland (DG) tissue were analyzed by gas chromatography. Potential relationships between the temporal proportion of each marker in the environment and in the digestive tract were tested using multivariate analysis. Proportions of diatoms and Dinophyceae biomarkers...
Tipo: Text Palavras-chave: Trophic ecology; Food sources; Pigments; Fatty acids; Trophic marker; Phytoplankton; Pecten maximus.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00431/54244/55772.pdf
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Seasonal habitat and length influence on the trophic niche of co-occurring tropical tunas in the eastern Atlantic Ocean ArchiMer
Sardenne, Fany; Diaha, N'Guessan Constance; Amande, Monin Justin; Zudaire, Iker; Couturier, Lydie; Metral, Luisa; Le Grand, Fabienne; Bodin, Nathalie.
In the Gulf of Guinea, bigeye Thunnus obesus (BET) and yellowfin tuna Thunnus albacares (YFT) are important for commercial fisheries and play a prominent ecological role as top predators. Using fatty acid profiles and carbon and nitrogen stable isotopes we examined their niche partitioning in this understudied region. Niche overlap was high (>70%), similar to percentages in other ocean basins. BET occupied a higher trophic position than YFT and fed on deeper prey (high δ15N values and high proportions of mono-unsaturated fatty acids). The trophic position of YFT decreased slightly in the last 15 years (δ15N values decrease ~0.5 ‰) suggesting a change in epipelagic communities, as observed in the eastern Pacific Ocean. Ontogenic changes were limited to...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00436/54796/56254.pdf
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Trophic ecology influence on metal bioaccumulation in marine fish: Inference from stable isotope and fatty acid analyses ArchiMer
Le Croizier, Gael; Schaal, Gauthier; Gallon, Regis; Fall, Massal; Le Grand, Fabienne; Munaron, Jean-marie; Rouget, Marie-laure; Machu, Eric; Le Loc'H, Francois; Lae, Raymond; De Morais, Luis Tito.
The link between trophic ecology and metal accumulation in marine fish species was investigated through a multi-tracers approach combining fatty acid (FA) and stable isotope (SI) analyses on fish from two contrasted sites on the coast of Senegal, one subjected to anthropogenic metal effluents and another one less impacted. The concentrations of thirteen trace metal elements (As, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sn, U, and Zn) were measured in fish liver. Individuals from each site were classified into three distinct groups according to their liver FA and muscle SI compositions. Trace element concentrations were tested between groups revealing that bioaccumulation of several metals was clearly dependent on the trophic guild of fish. Furthermore,...
Tipo: Text Palavras-chave: Trace elements; Biochemical tracers; Diet; Contamination; Senegal; Tropical fish.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00348/45908/45707.pdf
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Use of a lipid rich strain reveals mechanisms of nitrogen limitation and carbon partitioning in the haptophyte Tisochrysis lutea ArchiMer
Garnier, Matthieu; Bougaran, Gael; Pavlovic, Marija; Berard, Jean-baptiste; Carrier, Gregory; Charrier, Aurelie; Le Grand, Fabienne; Lukomska, Ewa; Rouxel, Catherine; Schreiber, Nathalie; Cadoret, Jean-paul; Rogniaux, Helene; Saint-jean, Bruno.
Haptophytes are a diverse monophyletic group with a worldwide distribution, known to be significantly involved in global climate regulation in their role as a carbon sink. Because nitrogen is a major limiting macronutrient for phytoplankton in oceans and for cultures of microalgae, understanding the involvement of nitrogen availability in haptophyte carbon partitioning is of global and biotechnological importance. Here, we made an ecophysiological study coupled with comprehensive large scale proteomic analysis to examine differences of behavior in reaction to nitrogen availability changes between a wild type strain of Tisochrysis lutea (WTc1) and a mutant strain (2Xc1) known to accumulate more storage lipids. Strains were grown in chemostats and studied...
Tipo: Text Palavras-chave: Algae; Isochrysis; Lipids; Nitrogen; Reverse genomic: proteomic.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00356/46702/46904.pdf
Registros recuperados: 7
Primeira ... 1 ... Última
 

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