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| Registros recuperados: 28 | |
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| Vauchel, Peggy; Kaas, Raymond; Arhaliass, Abdellah; Baron, Regis; Legrand, Julien. |
| Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The main step in the extraction protocol used in the alginate industry is that of alkaline extraction. A batch process is used for this step, which is time-, water-, and reactant-consuming. The possibility of extracting by reactive extrusion was investigated. The reactive extrusion process appeared to be more efficient than the batch process for the alkaline extraction of alginates from Laminaria digitata in several key ways: Time demand is reduced from about an hour to only few minutes, water and reactant requirements are divided by more than a factor 2, extraction yield is 15% higher (relative enhancement), and the rheological... |
| Tipo: Text |
Palavras-chave: Intrinsic viscosity; Reactive extrusion; Laminaria digitata; Alkaline extraction; Alginate. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6255.pdf |
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| Robert, Rene; Chretiennot-dinet, Marie-josèphe; Kaas, Raymond; Martin-jezequel, Véronique; Moal, Jeanne; Le Coz, Jean-rene; Nicolas, Jean-louis; Bernard, Eudes; Connan, Jean-paul; Le Dean, Loic; Le Gourrierec, Gaetane; Leroy, Bertrand; Quere, Claudie. |
| in mollusc hatcheries. Consequently, we assessed themost commonly used species to establish their growth and size profiles, their cytomorphological, biochemical, biomolecular identification as well as their cytometer signs, and also their ability to grow under extreme conditions of temperature and salinity. This work aimed at matching the conformity of the strains used in Argenton (dispatched to most of the French commercial hatcheries) to those of a referenced culture collection. A previous screening preceded this study, because of the 45 species and/or clones held originally, Argenton kept no more than 15 species. As most of the latter are also represented in referenced collection, our strains are therefore correctly identified. On the other hand, the... |
| Tipo: Text |
Palavras-chave: Ecological limits; Biomolecular profile; Flow cytometry; Biochemical composition; Cytomorphology; Phytoplankton; Mollusc; Hatchery; Ecotolérance; Profil biomoléculaire; Cytométrie en flux; Composition biochimique; Cytomorphologie; Phytoplancton; Mollusques; Ecloserie. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/rapport-1546.pdf |
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| Baudelet, Paul-hubert; Gagez, Anne-laure; Berard, Jean-baptiste; Juin, Camille; Bridiau, Nicolas; Kaas, Raymond; Thiery, Valerie; Cadoret, Jean-paul; Picot, Laurent. |
| The glaucophyte Cyanophora paradoxa (Cp) was chemically investigated to identify pigments efficiently inhibiting malignant melanoma, mammary carcinoma and lung adenocarcinoma cells growth. Cp water and ethanol extracts significantly inhibited the growth of the three cancer cell lines in vitro, at 100 mu g.mL(-1). Flash chromatography of the Cp ethanol extract, devoid of c-phycocyanin and allophycocyanin, enabled the collection of eight fractions, four of which strongly inhibited cancer cells growth at 100 mu g.mL(-1). Particularly, two fractions inhibited more than 90% of the melanoma cells growth, one inducing apoptosis in the three cancer cells lines. The detailed analysis of Cp pigment composition resulted in the discrimination of 17 molecules, ten of... |
| Tipo: Text |
Palavras-chave: Pigments; Microalgae; Cyanophora paradoxa; Melanoma; Cancer; Apoptosis; Zeaxanthin; Cryptoxanthin. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00177/28818/27289.pdf |
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| Pasquet, Virginie; Morisset, Perrine; Ihammouine, Said; Chepied, Amandine; Aumailley, Lucie; Berard, Jean-baptiste; Serive, Benoit; Kaas, Raymond; Lanneluc, Isabelle; Thiery, Valerie; Lafferriere, Mathieu; Piot, Jean-marie; Patrice, Thierry; Cadoret, Jean-paul; Picot, Laurent. |
| Dunaliella tertiolecta (DT) was chemically investigated to isolate molecules inhibiting cancer cell proliferation and inducing apoptosis in vitro. The potency to inhibit cell growth was used for the bio-guided fractionation and isolation of active compounds using chromatographic techniques. The DT dichloromethane extract exhibited a strong anti-proliferative activity on MCF-7 and LNCaP cells, and was further fractionated and sub-fractionated by RP-HPLC. High resolution mass spectrometry and spectrophotometric analysis unequivocally identified violaxanthin as the most antiproliferative molecule present in DT DCM extract. Violaxanthin purified from DT induced MCF-7 dose- dependent growth inhibition in continuous and discontinuous treatments, at... |
| Tipo: Text |
Palavras-chave: Pigments; Microalgae; Dunaliella; Violaxanthin; Carotenoid; Cancer; Apoptosis. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00040/15142/12575.pdf |
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| Nef, Charlotte; Henry, Céline; Nicolau, Elodie; Bérard, Jean-baptiste; Hervé, Fabienne; Caruana, Amandine; Kaas, Raymond; Mairet, Francis; Garnier, Matthieu. |
| Cobalamin (vitamin B12) is a cobalt-containing enzymatic cofactor involved in methionine synthesis. Provided only by select bacteria and archaea in marine systems, this vitamin is known to limit primary production in different oceanic areas. Understanding the consequences of cobalamin limitation on phytoplankton physiology is of great interest, notably for cobalamin-dependent haptophytes that significantly contribute to oceanic carbon fixation and sulfur cycle through dimethyl sulfonio propionate (DMSP) synthesis. Here, the effect of cobalamin limitation was compared to nitrogen limitation on the model haptophyte Tisochrysis lutea grown in chemostats, combining comparative proteomics with the analysis of major macromolecules and specific osmolytes. Our... |
| Tipo: Text |
Palavras-chave: Cobalamin; Vitamin B-12; Haptophyte microalgae; Tisochrysis lutea; DMSP; Chemostat; Comparative proteomics; Metabolism. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00654/76575/77711.pdf |
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| Serive, Benoit; Nicolau, Elodie; Berard, Jean-baptiste; Kaas, Raymond; Pasquet, Virginie; Picot, Laurent; Cadoret, Jean-paul. |
| Phytoplankton, with an estimated 30 000 to 1 000 000 species clustered in 12 phyla, presents a high taxonomic and ecophysiological diversity, reflected by the complex distribution of pigments among the different algal classes. High performance liquid chromatography is the gold standard method for qualitative and quantitative analysis of phytoplankton pigments in seawater and culture samples, but only a few pigments can be used as robust chemotaxonomic markers. A major challenge is thus to identify new ones, characteristic of a strain, species, class or taxon that cannot be currently identified on the basis of its pigment signature. Using an optimized extraction process coupled to a HPLC de-replication strategy, we examined the pigment composition of 37... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00373/48416/48627.pdf |
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| Bougaran, Gael; Le Dean, Loic; Lukomska, Ewa; Picquet, Marie-lise; Kaas, Raymond; Muller-feuga, Arnaud. |
| La prymnésiophycée Isochrysis galbana affinis Tahiti (T -iso) est une micro algue marine classiquement utilisée comme nourriture de larves de mollusques et de proies vivantes de poissons d'aquaculture dans la plupart des écloseries produisant des juvéniles de ces espèces. Aujourd'hui, de nombreuses écloseries de mollusques et de poissons l'utilisent en association avec d'autres espèces telles que Pavlova lutheri, Chaetoceros calcitrans et Skeletonema costatum. Isolée à Tahiti par JL Martin en 1975 (comm. pers.), cette algue s'est rapidement imposée dans la nutrition larvaire des crevettes et des mollusques en raison de sa croissance rapide en conditions tropicales et de ses qualités nutritionnelles, en relation avec sa forte teneur en acides gras... |
| Tipo: Text |
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| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00304/41508/40716.pdf |
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| Maheswari, Uma; Jabbari, Kamel; Petit, Jean-louis; Porcel, Betina M.; Allen, Andrew E.; Cadoret, Jean-paul; De Martino, Alessandra; Heijde, Marc; Kaas, Raymond; La Roche, Julie; Lopez, P.; Martin-jezequel, Veronique; Meichenin, Agnes; Mock, Thomas; Parker, Micaela Schnitzler; Vardi, Assaf; Armbrust, E. Virginia; Weissenbach, Jean; Katinka, Michael; Bowler, Chris. |
| Background: Diatoms represent the predominant group of eukaryotic phytoplankton in the oceans and are responsible for around 20% of global photosynthesis. Two whole genome sequences are now available. Notwithstanding, our knowledge of diatom biology remains limited because only around half of their genes can be ascribed a function based onhomology-based methods. High throughput tools are needed, therefore, to associate functions with diatom-specific genes. Results: We have performed a systematic analysis of 130,000 ESTs derived from Phaeodactylum tricornutum cells grown in 16 different conditions. These include different sources of nitrogen, different concentrations of carbon dioxide, silicate and iron, and abiotic stresses such as low temperature and low... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00017/12810/9758.pdf |
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| Antoine, Loic; Lemoine, Maud; Boulben, Sylviane; Kaas, Raymond; Laurans, Martial; Viard, Frédérique; Potin, Philippe. |
| La synthèse de l’expertise collégiale menée par l’Ifremer et la station biologique de Roscoff permet de préconiser le maintien des cultures de Undaria pinnatifida dans les zones déjà mises en culture à condition de se cantonner aux pratiques culturales des exploitants installés depuis longtemps, avec un suivi et sans expérimenter de nouvelles pratiques pour lesquelles il n’y a pas de recul. Là où des essais ont eu lieu en 2010 et 2011 (Projet Chaco), il serait nécessaire de faire rapidement un état des lieux de la présence ou l'absence d'Undaria pinnatifida en milieu naturel afin de mesurer l'impact de ces essais. En l’état actuel des connaissances il n’y a pas de données scientifiques qui permettent de garantir le respect de l’article 24 du R(CE) N°... |
| Tipo: Text |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00086/19740/17380.pdf |
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| Bougaran, Gael; Rouxel, Catherine; Dubois, Nolwenn; Kaas, Raymond; Grouas, Sophie; Lukomska, Ewa; Le Coz, Jean-rene; Cadoret, Jean-paul. |
| Microalgae offer a high potential for energetic lipid storage as well as high growth rates. They are therefore considered promising candidates for biofuel production, with the selection of high lipid-producing strains a major objective in projects on the development of this technology. We developed a mutation-selection method aimed at increasing microalgae neutral lipid productivity. A two step method, based on UVc irradiation followed by flow cytometry selection, was applied to a set of strains that had an initial high lipid content and improvement was assessed by means of Nile-red fluorescence measurements. The method was first tested on Isochrysis affinis galbana (T-Iso). (...) |
| Tipo: Text |
Palavras-chave: Strain selection; Isochrysis; Neutral lipid; Ultra violet; Flux cytometry; Biofuel. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00085/19643/17418.pdf |
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| Nef, Charlotte; Jung, Sebastien; Mairet, Francis; Kaas, Raymond; Grizeau, Dominique; Garnier, Matthieu. |
| Vitamin B-12 (cobalamin) can control phytoplankton development and community composition, with around half of microalgal species requiring this vitamin for growth. B-12 dependency is determined by the absence of cobalamin-independent methionine synthase and is unrelated across lineages. Despite their important role in carbon and sulphur biogeochemistry, little is known about haptophytes utilization of vitamin B-12 and their ability to cope with its limitation. Here we report the first evaluation of B-12 auxotrophy among this lineage based on molecular data of 19 species from 9 families. We assume that all species encode only a B-12-dependent methionine synthase, suggesting ubiquitous B-12 auxotrophy in this phylum. We further address the effect of... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00504/61523/65398.pdf |
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| Baron, Regis; Socol, Marius; Arhaliass, A.; Bruzac, Sandrine; Le Roux, Karine; Del Pino, J. Rodriguez; Berge, Jean-pascal; Kaas, Raymond. |
| We describe a one-step bio-refinery process for shrimp composites by-products. Its originality lies in a simple rapid (6 h) biotechnological cuticle fragmentation process that recovers all major compounds (chitins, peptides and minerals in particular calcium). The process consists of a controlled exogenous enzymatic proteolysis in a food-grade acidic medium allowing chitin purification (solid phase), and recovery of peptides and minerals (liquid phase). At a pH of between 3.5 and 4, protease activity is effective, and peptides are preserved. Solid phase demineralization kinetics were followed for phosphoric, hydrochloric, acetic, formic and citric acids with pKa ranging from 2.1 to 4.76. Formic acid met the initial aim of (i) 99 % of demineralization yield... |
| Tipo: Text |
Palavras-chave: Bio-refinery; Acidic enzymatic proteolysis; Shrimp cuticles; Demineralization kinetics and modeling. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00281/39244/37809.pdf |
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| Kaas, Raymond. |
| Les 300 km du littoral breton touchés par les hydrocarbures de l'Amoco Cadiz sont parmi les plus productifs quant à l'exploitation des algues. L'ISTPM a suivi l'évolution des peuplements de Laminaria digitata et de Chondrus crispus, algues les plus utilisées par les industries locale et fait état des perturbations physiologiques engendrées par la pollution par les hydrocarbures. |
| Tipo: Text |
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| Ano: 1980 |
URL: https://archimer.ifremer.fr/doc/00593/70502/68653.pdf |
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| Kaas, Raymond. |
| Introduction. The amount of hydrocarbons dumped into the sea is currently estimated at 6 to 16 million tons per year. This pollution comes from various sources: Chronic discharges associated with human activity such as oil tanker deballasting or discharges from coastal petroleum processing facilities; natural chronic discharges; accidental discharges like leaks coming from drilling well heads or oil tanker accidents. Natural spills happen, in general, in a relatively unobtrusive way and their effects are quickly diminished by significant dilution and rapid degradation of the various components. Oil spills, however, are characterised by a massive and occasional supply of hydrocarbons. The "Amoco Cadiz" shipwreck fits in with this last case and has seemed... |
| Tipo: Text |
Palavras-chave: Seaweeds; Pollution Effects; Marine Pollution; Oil Spill. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/publication-1950.pdf |
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| Registros recuperados: 28 | |
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