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| Registros recuperados: 68 | |
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| Remize, Marine; Planchon, Frederic; Loh, Ai Ning; Le Grand, Fabienne; Bideau, Antoine; Le Goic, Nelly; Fleury, Elodie; Miner, Philippe; Corvaisier, Rudolph; Volety, Aswani; Soudant, Philippe. |
| The present study sought to characterize the synthesis pathways producing the essential polyunsaturated fatty acid (PUFA) 20:5n-3 (EPA). For this, the incorporation of 13C was experimentally monitored into 10 fatty acids (FA) during the growth of the diatom Chaetoceros muelleri for 24 h. Chaetoceros muelleri preferentially and quickly incorporated 13C into C18 PUFAs such as 18:2n-6 and 18:3n-6 as well as 16:0 and 16:1n-7, which were thus highly 13C-enriched. During the experiment, 20:5n-3 and 16:3n-4 were among the least-enriched fatty acids. The calculation of the enrichment percentage ratio of a fatty acid B over its suspected precursor A allowed us to suggest that the diatom produced 20:5n-3 (EPA) by a combination between the n-3 (via 18:4n-3) and n-6... |
| Tipo: Text |
Palavras-chave: Synthesis pathway; Diatom; 20:5n-3 (EPA); Chaetoceros muelleri; Acyl-editing mechanism; Compound-specific isotope analysis. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00630/74257/73887.pdf |
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| Tallec, Kevin; Blard, Océane; González-fernández, Carmen; Brotons, Guillaume; Berchel, Mathieu; Soudant, Philippe; Huvet, Arnaud; Paul-pont, Ika. |
| Plastic debris are classified as a function of their size and recently a new class was proposed, the nanoplastics. Nano-sized plastics have a much greater surface area to volume ratio than larger particles, which increases their reactivity in aquatic environment, making them potentially more toxic. Only little information is available about their behavior whereas it crucially influences their toxicity. Here, we used dynamic light scattering (DLS) to explore the influence of environmental factors (fresh- and saltwater, dissolved organic matter) on the behavior (surface charge and aggregation state) of three different nano-polystyrene beads (50 nm), with (i) no surface functionalization (plain), (ii) a carboxylic or (iii) an amine functionalization. Overall,... |
| Tipo: Text |
Palavras-chave: Nanoplastic; Dynamic light scattering; Behavior; Aggregation; Salinity; Organic matter. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59652/62684.pdf |
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| Marchetti, Julie; Da Costa, Fiz; Bougaran, Gael; Quere, Claudie; Soudant, Philippe; Robert, Rene. |
| The lipid class and the fatty acid compositions of microalgae highly influence bivalve larval and post-larval development. Light is an essential environmental factor for microalgal culture, and quantity and quality of light may induce changes in the biochemical composition of the algae. The objective of this study was to investigate the effect of light spectrum (blue vs. white light) on lipid class and fatty acid compositions of Tisochrysis lutea cultured in a chemostat. Two different dilution rates (D) were assayed for each light spectrum: 0.2 and 0.7 day−1. Triacylglycerol (TAG), sterol, and hydrocarbon (HC) content increased sharply at low D. The proportion of alkenones was significantly reduced under blue light. Polyunsaturated fatty acids (PUFA), and... |
| Tipo: Text |
Palavras-chave: Tisochrysis lutea; Blue light; Dilution rate; Lipid classes; Fatty acids; Chemostat. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00412/52299/53355.pdf |
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| Castrec, Justine; Hegaret, Helene; Alunno-bruscia, Marianne; Picard, Mailys; Soudant, Philippe; Petton, Bruno; Boulais, Myrina; Suquet, Marc; Queau, Isabelle; Ratiskol, Dominique; Foulon, Valentin; Le Goic, Nelly; Fabioux, Caroline. |
| Harmful algal blooms are a threat to aquatic organisms and coastal ecosystems. Among harmful species, the widespread distributed genus Alexandrium is of global importance. This genus is well-known for the synthesis of paralytic shellfish toxins which are toxic for humans through the consumption of contaminated shellfish. While the effects of Alexandrium species upon the physiology of bivalves are now well documented, consequences on reproduction remain poorly studied. In France, Alexandrium minutum blooms have been recurrent for the last decades, generally appearing during the reproduction season of most bivalves including the oyster Crassostrea gigas. These blooms could not only affect gametogenesis but also spawning, larval development or juvenile... |
| Tipo: Text |
Palavras-chave: Harmful algal bloom (HAB); Paralytic shellfish toxin (PST); Crassostrea gigas; Gametes; Larvae. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00469/58099/60512.pdf |
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| Seguineau, Catherine; Racotta, Ilie; Palacios, Elena; Delaporte, Maryse; Moal, Jeanne; Soudant, Philippe. |
| In a previous study, dietary supplementation with arachidonic acid (ARA) to oysters Crassostrea gigas increased haemocyte numbers, phagocytosis, and production of reactive oxygen species level (ROS) by haemocytes (Delaporte et al., 2006). To assess if the observed stimulation of these cellular responses resulted from changes of ARA-related prostaglandin (PG) production, we analysed prostaglandin E2 metabolite (PGEM) content on the same oysters fed three levels of ARA. Dietary supply of polyunsaturated fatty acids (PUFA) could also induce an oxidative stress that could similarly increase cellular responses; therefore, two indicators of oxidative stress were analysed: peroxidation level and antioxidant defence status. Together the observed positive... |
| Tipo: Text |
Palavras-chave: Prostaglandins; N-6 unsaturated fatty acids; Lipid peroxidation; Antioxidants; ROS production. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00040/15103/12785.pdf |
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| Stachowski-haberkorn, Sabine; Guesdon, Stephane; Bechemin, Christian; Chiffoleau, Jean-francois; Brach-papa, Christophe; Soudant, Philippe; Beker, Beatriz; Jadas-hécart, Alain. |
| TOPHYPAC is a field study that was conducted in the Charente river estuary (Marennes-Oléron bay). The main goal was to assess the possible impact of chemical contamination with copper and pesticides on phytoplankton communities. Physical, chemical (nutrients, metals and pesticides) and biological (phytoplankton community) parameters were monitored in the field during three years, from 2011 to 2014. In 2012 and 2013, field sampling was coupled with experimental exposure of phytoplankton communities to copper and to an herbicide cocktail, after transportation to the lab: the effects were assessed using photosynthesis endpoint and cellular densities. TOPHYPAC allowed to set the framework of Charente estuary contamination with pesticides: herbicides glyphosate... |
| Tipo: Text |
Palavras-chave: Continuum eau douce/eau côtière; Pesticides; Métaux; Communautés phytoplanctoniques; Efficacité de photosynthèse; PICT; Tolérance; Cytométrie en flux; Toxicité chronique; Freshwater/coastal water continuum; Pesticides; Metals; Phytoplankton communities; Photosynthesis efficiency; PICT; Tolerance; Flow cytometry; Chronic toxicity. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00300/41115/40289.pdf |
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| Hegaret, Hélène; Wikfors, Gary H.; Soudant, Philippe; Lambert, Christian; Shumway, Sandra E.; Berard, Jean-baptiste; Lassus, Patrick. |
| The possible effect of Alexandrium spp. containing paralytic shellfish poisoning (PSP) toxins on the hemocytes of oysters was tested experimentally. In one trial, eastern oysters, Crassostrea virginica Gmelin, were exposed to bloom concentrations of the sympatric dinoflagellate, Alexandrium fundyense Balech, alone and in a mixture with a non-toxic diatom, Thalassiosira weissflogii (Grun) Fryxell et Hasle. Subsequently, another experiment exposed Pacific oysters, Crassostrea gigas Thunberg, to a mixed suspension of the sympatric, toxic species Alexandrium catenella (Whedon et Kofoid) Balech, with T. weissflogii. Measurements of numbers of oyster hemocytes, percentages of different cell types, and functions (phagocytosis, reactive oxygen species (ROS)... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3328.pdf |
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| Labreuche, Yannick; Le Roux, Frederique; Henry, Joel; Zatylny, Celine; Huvet, Arnaud; Lambert, Christophe; Soudant, Philippe; Mazel, Didier; Nicolas, Jean-louis. |
| Extracellular products (ECPs) of the pathogenic Vibrio aestuarianus 01/32 were previously reported to display lethality in Crassostrea gigas oysters and to cause morphological changes and immunosuppression in oyster hemocytes. To identify the source of this toxicity, biochemical and genetic approaches were developed. ECP protease activity and lethality were shown to be significantly reduced following incubation with metal chelators, suggesting the involvement of a zinc metalloprotease. An open reading frame of 1836 bp encoding a 611-aa metalloprotease (designated yam) was identified. The deduced protein sequence showed high homology to other Vibrio metalloproteases reported to be involved in pathogenicity. To further confirm the role of this enzyme in ECP... |
| Tipo: Text |
Palavras-chave: Vibrio aestuarianus; Metalloprotease; Crassostrea gigas; Oyster; Hemocytes; Extracellular products. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00015/12649/9588.pdf |
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| Registros recuperados: 68 | |
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