Consulta: creatorFacets:"Kaas, Raymond"
Registros recuperados: 28
Data/hora: 02/06/2024 10:53:00

Digital expression profiling of novel diatom transcripts provides insight into their biological functions
Provedor de dados: 5
Autores: 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
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00017/12810/9758.pdf

Community analysis of pigment patterns from 37 microalgae strains reveals new carotenoids and porphyrins characteristic of distinct strains and taxonomic groups
Provedor de dados: 5
Autores: 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
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00373/48416/48627.pdf

Optimisation de l'enrichissement nutritif pour la culture d' Isochrysis galbana affinis Tahiti
Provedor de dados: 5
Autores: Bougaran, Gael; Le Dean, Loic; Loizel, Céline; Lukomska, Ewa; Picquet, Marie-lise; Kaas, Raymond; Muller-feuga, Arnaud.
La prymnésiophycée Isochrysis galbana affinis Tahiti (T -iso) est 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. La solution d'enrichissement de Conway (SEC), élaborée en 1966 par Walne, est largement utilisée pour la production de T -iso en batch. Cependant, les apports nutritifs de cette solution d'enrichissement ne sont pas spécifiquement optimisés pour la culture de cette algue, participant à engendrer des coûts de production élevés (Valenzuala-Espinoza et al., 1999 ; Fabregas et al., 1986) et des effluents inépuisés. Dans les 15 dernières années, plusieurs auteurs sont parvenus à réduire le coût de solutions...
Tipo: Text
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00304/41519/40727.pdf

Possibilité de culture de l'algue alimentaire Undaria Pinnatifida sur les côtes de France - L'ensemencement
Provedor de dados: 5
Autores: Perez, Rene; Kaas, Raymond.
En 1971, un ostréiculteur de l'étang de Thau découvrait dans son parc à huîtres une algue qui lui paraissait étrange pour le lieu : il s' agissait en effet de l'espèce Undaria pinnatifida (MARVEY) SURINGAR (fig. 1), originaire du Japon, sans doute introduite involontairement sous forme de plantules ou de spores en même temps que le naissain d'huîtres importé d'Extrême-Orient.
Tipo: Text
Ano: 1980
URL: http://archimer.ifremer.fr/doc/00046/15738/13140.pdf

Elements for optimizing a one-step enzymatic bio-refinery process of shrimp cuticles: Focus on enzymatic proteolysis screening
Provedor de dados: 5
Autores: Baron, Regis; Socol, Marius; Kaas, Raymond; Arhaliass, A.; Rodriguez Del Pino, J.; Le Roux, Karine; Donnay-moreno, Claire; Berge, Jean-pascal.
This article complements an earlier work published in 2015 Baron et al. (2015) that showed the interest of a shrimp shells bio-refining process. We compare here the effect of eleven commercial proteases at pH 3.5 or 4.0 on a residual amount of shrimp shells proteins after 6 hours at 50 °C. The two pH are obtained when respectively 40 and 25 mmol of formic acid are added to 5 g of mild dried shell. Deproteinisation yield above 95% are obtained. Residual amino acids profile in the solid phase was identical for the eleven proteases except for pepsin which was similar to the raw material profile. A significant relative increase in the proportion of Glycine is observed for the ten other cases. Likewise, shapes of size exclusion chromatograms of the dissolved...
Tipo: Text
Palavras-chave: Bio-refinery; Shrimp cuticles; Acidic enzymatic proteolysis.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00388/49957/50530.pdf

Optimisation de la production en écloserie de mollusques : Mise au point d'un pilote industriel de production phytoplanctonique en continu et des techniques associées pour leur intégration en écloserie commerciale
Provedor de dados: 5
Autores: Angeri, S.; Bougaran, Gael; Connan, Jean-paul; Jouin, Jean-claude; Kaas, Raymond; Le Dean, Loic; Legrand, J.; Loubiere, K.; Lukomska, Ewa; Olivo, Erell; Picquet, Marie-lise; Pruvost, J.; Robert, Rene.
Les travaux présentés dans le cadre de ce rapport d'activité rendent compte des avancées réalisées sur le plan (1) biologique, avec d'une part une étude sur le comportement du genre Chaetoceros en culture continue et, d'autre part, les résultats d'expérimentations sur les performances d'élevages larvaires réalisés sur la base de cultures de microalgues en continu, et (2) technologique, avec la continuité des actions de développement du photobioréacteur destiné aux écloseries commerciales ainsi que des périphériques indispensables à son intégration dans le secteur aquacole.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00304/41518/40726.pdf

How haptophytes microalgae mitigate vitamin B-12 limitation
Provedor de dados: 5
Autores: 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
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00504/61523/65398.pdf

Technique de culture pour les cotes bretonnes de l'algue alimentaire Undaria pinnatifida.  Tableau de marché - étude économique
Provedor de dados: 5
Autores: Perez, René; Kaas, Raymond; Barbaroux, Olivier; Arbault, Suzanne; Le Bayon, Nicolas; Moigne, J.
Introduction Starting in 1986, the ANVAR contributed well appreciated financial support in order to set up an original seeding technique characterized by artificial seeding production in a laboratory. This advantageous new way of seeding, i.e. independency from nature, yield increase and true competitiveness compared to traditional methods, nevertheless requires strict adherence to a procedure progressively elaborated during numerous trials in laboratory as well as at sea. The program ended in July 1989 after testing the cultivation protocol on a 2 hectare exploitation scale, in order to better detect what could be improved to greatly increase productivity, facilitate the work of the harvester and to better adapt the operating mode to environmental...
Tipo: Text
Palavras-chave: Economic survey; Brittany; Farming technique; Seaweed; Undaria pinnatifida; Etude économique; Bretagne; Technique de culture; Algue; Undaria pinnatifida.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/1990/rapport-1659.pdf

Study on the microalgal pigments extraction process: Performance of microwave assisted extraction
Provedor de dados: 5
Autores: Pasquet, Virginie; Cherouvrier, Jean-rene; Farhat, Firas; Thiery, Valerie; Piot, Jean-marie; Berard, Jean-baptiste; Kaas, Raymond; Serive, Benoit; Patrice, Thierry; Cadoret, Jean-paul; Picot, Laurent.
The performance of microwaves irradiation (MAE and VMAE) to extract pigments from two marine microalgae was compared to conventional processes (cold and hot soaking and ultrasound-assisted extraction). Pigments were quantified by RP-HPLC and extraction performance was assessed regarding rapidity, reproducibility and extraction yields. Scanning electron microscopy was used at all extraction steps to assess the impact of the process on microalgal cell integrity. Freeze-drying and pigments extraction preserved microalgae cell integrity (except sonication) and evoked agglutination in superposed cells layers. All processes performed on Dunaliella tertiolecta (chlorophyte) lead to rapid pigments extraction, and equivalent pigments extraction yields, the absence...
Tipo: Text
Palavras-chave: Pigments; Microalgae; Microwave; Extraction; Chlorophyll; Fucoxanthin; Carotene; MAE; VMAE.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00029/14059/11533.pdf

Culture en continu de Isochrysis galbana affinis Tahiti
Provedor de dados: 5
Autores: 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
Ano: 2001
URL: http://archimer.ifremer.fr/doc/00304/41508/40716.pdf

Emergence d'une filière de culture de macro-algues en Bretagne et problème relatif à une espèce non indigène, le wakame (Undaria pinnatifida)
Provedor de dados: 5
Autores: 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
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00086/19740/17380.pdf

Dynamical modelling of a reactive extrusion process: Focus on residence time distribution in a fully intermeshing co-rotating twin-screw extruder and application to an alginate extraction process
Provedor de dados: 5
Autores: Baron, Regis; Vauchel, Peggy; Kaas, Raymond; Arhaliass, Abdellah; Legrand, Jack.
The context of this study is the modelling of reactive extrusion process based on an alginate extraction protocol. Residence Time Distribution (RTD) is one important part to predict the kinetics of reactive compounds. A simple model is proposed to predict RTD in fully intermeshing co-rotating twin-screw extruders without reaction. This model, which can be easily extended to reactive case in a future work, is based on the extension of an axial dispersion model, including control parameters (screw speed and flow rate) and geometrical parameters (screw profile and die design). Simulations were performed for various operating and geometrical conditions so as to illustrate possibilities offered by the proposed model. Validation was conducted for two different...
Tipo: Text
Palavras-chave: Alginate; Extraction; Extrusion; Mathematical modelling; Residence time distribution; Simulation; Laminaria digitata.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00005/11592/8985.pdf

Antiproliferative Activity of Cyanophora paradoxa Pigments in Melanoma, Breast and Lung Cancer Cells
Provedor de dados: 5
Autores: 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

La culture des algues marines dans le monde
Provedor de dados: 5
Autores: Perez, René; Kaas, Raymond; Campello, Francois; Arbault, Suzanne; Barbaroux, Olivier.
Shouldn't Earth, the human planet, be called the algae planet? First appearing 3.5 billion years ago, algae have always been objective allies of life and humans. Brought about by algae, oxygen and the ozone layer allowed plant and animal life to develop in oceans and on continents. They offer spawning grounds and feeding grounds for marine fauna....
Tipo: Text
Ano: 1992
URL: http://archimer.ifremer.fr/doc/1992/rapport-4402.pdf

Antiproliferative Activity of Violaxanthin Isolated from Bioguided Fractionation of Dunaliella tertiolecta Extracts
Provedor de dados: 5
Autores: 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

Transient initial phase in continuous culture of Isochrysis galbana affinis Tahiti
Provedor de dados: 5
Autores: Bougaran, Gael; Le Dean, Loic; Lukomska, Ewa; Kaas, Raymond; Baron, Regis.
Starting microalgae continuous culture generally includes a preliminary batch culture to obtain sufficient cell density. It is possible to apply continuous regime from the beginning of the culture (IC mode) rather than to begin by an initial batch (IB mode). It is our purpose to check that both initial modes lead to identical steady-state cell characteristics. The microalga Isochrysis galbana affinis Tahiti was used for this comparative study. With an initial cell density of 5 x 10(5) cell ml(-1) and a dilution rate of about 1.0 d(-1), both IB and IC modes led to identical cell density once steady-state is reached between 6 and 8 d after inoculation in the two cases. Cell concentration of chlorophyll a and pheopigment a were found to be similar for IB and...
Tipo: Text
Palavras-chave: Isochrysis; Cell quota; Photosynthesis; Steady state; Continuous culture.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/publication-597.pdf

Cobalamin Scarcity Modifies Carbon Allocation and Impairs DMSP Production Through Methionine Metabolism in the Haptophyte Microalgae Tisochrysis lutea
Provedor de dados: 5
Autores: 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

Les consequences de l'echouement de l'Amoco Cadiz" sur les peuplements algaux exploitables
Provedor de dados: 5
Autores: 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

Optimizing conditions for the continuous culture of Isochrysis affinis galbana relevant to commercial hatcheries
Provedor de dados: 5
Autores: Marchetti, Julie; Bougaran, Gael; Le Dean, Loic; Megrier, Cyril; Lukomska, Ewa; Kaas, Raymond; Olivo, Erell; Baron, Regis; Robert, Rene; Cadoret, Jean-paul.
Optimal culture conditions were investigated for the continuous culture of Isochrysis affinis galbana (T-Iso) by assessing the effects of irradiance, temperature, pH and nitrogen and phosphorus requirements. Assessment of the growth rate-irradiance relationship in a turbidostat experiment highlighted that an optimum irradiance efficiency for growth (E-mu) occurred at irradiance much lower than the saturating level. Furthermore, our modeling approach for productivity pointed out that an optimal set of irradiance and dilution rate could be achieved in order to maximize irradiance efficiency. Optimal conditions for growth were assessed for temperature, pH and irradiance by means of a factorial design experiment. The resulting model predicted that optimal...
Tipo: Text
Palavras-chave: Isochrysis affinis galbana; Irradiance efficiency; Factor interaction; Nutrient limitation; Microalgae cultures.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00076/18736/16465.pdf

Kinetic study of solid phase demineralization by weak acids in one-step enzymatic bio-refinery of shrimp cuticles
Provedor de dados: 5
Autores: 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

Kinetics modeling of alginate alkaline extraction from Laminaria digitata
Provedor de dados: 5
Autores: Vauchel, Peggy; Le Roux, Karine; Kaas, Raymond; Arhaliass, Abdellah; Baron, Regis; Legrand, Jack.
Alginates being depolymerized during their alkaline extraction, reducing extraction time could help producing higher rheological quality alginates. The purpose of the present work is to study fresh Laminaria digitata destructuration during alkaline extraction and its link to extraction kinetics. Both alginate extraction yield and mean diameter of algae particles were followed for different values of agitation level and initial size of algae pieces. Results highlighted the existence of a link between extraction yield and algal destructuration. Those elements and the specificity of L. digitata structure have been taken into account to propose a kinetics model based on a fluid-particle reaction with decreasing size particles. The model parameters have been...
Tipo: Text
Palavras-chave: Model; Laminaria digitata; Alkaline extraction kinetics; Alginate.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6315.pdf

L'échouement de l'Amoco Cadiz : conséquences sur les peuplements algaux des côtes bretonnes
Provedor de dados: 5
Autores: 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
Ano: 1980
URL: https://archimer.ifremer.fr/doc/00593/70502/68653.pdf

Essai de cryoconservation des gamétophytes de l'algue alimentaire Undaria pinnatifida (Laminariale)
Provedor de dados: 5
Autores: Arbault, Suzanne; Renard, Philippe; Pérez, Rene; Kaas, Raymond.
Low temperature tolerance was determined for gametophytes of food alga Undaria pinnatifida according to various cryopreservation methods. Survival durations after storage in a medium containing 28% glycerol at −80 °C or in a 5-10% glycerol solution at −196 °C were only 9 and 4 days respectively. On the other hand, cooling at 5 °C/min. and storage at −15 °C for 15 minutes, without cryoprotective medium, did not reduce viability but this was highly decreased by storage for 15 minutes at −30 or −196 °C, with or without DMSO. The morphological cooling injuries were depigmentation and/or a contraction of the cells.
Tipo: Text
Palavras-chave: Algue; Cryoconservation; Gamétophyte; Undaria pinnatifida; Alga; Cryopreservation; Gametophyte; Undaria pinnatifida.
Ano: 1990
URL: http://archimer.ifremer.fr/doc/00189/30071/28559.pdf

A New Process for Extracting Alginates from Laminaria digitata: Reactive Extrusion
Provedor de dados: 5
Autores: 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

Amélioration des productions phytoplanctoniques en écloserie de mollusques : caractérisation des microalgues fourrage
Provedor de dados: 5
Autores: 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

Decrease in dynamic viscosity and average molecular weight of alginate from Laminaria digitata during alkaline extraction
Provedor de dados: 5
Autores: Vauchel, Peggy; Arhaliass, Abdellah; Legrand, Jack; Kaas, Raymond; Baron, Regis.
Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1-4 h in duration were determined, indicating depolymerization of alginates: average molecular weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological...
Tipo: Text
Palavras-chave: Laminaria digitata; Intrinsic viscosity; Depolymerization; Average molecular weight; Alkaline extraction; Alginate.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4060.pdf

Microwave-assisted extraction of phycobiliproteins from Porphyridium purpureum
Provedor de dados: 5
Autores: Juin, Camille; Cherouvrier, Jean-rene; Thiery, Valerie; Gagez, Anne-laure; Berard, Jean-baptiste; Joguet, Nicolas; Kaas, Raymond; Cadoret, Jean-paul; Picot, Laurent.
In the present study, microwave-assisted extraction was first employed to extract the phycobiliproteins of Porphyridium purpureum (Pp). Freeze-dried Pp cells were subjected to microwave-assisted extraction (MAE) to extract phycoerythin (PE), phycocyanin (PC), and allophycocyanin (APC). MAE combined reproducibility and high extraction yields and allowed a 180- to 1,080-fold reduction of the extraction time compared to a conventional soaking process. The maximal PE extraction yield was obtained after 10-s MAE at 40 A degrees C, and PE was thermally damaged at temperatures higher than 40 A degrees C. In contrast, a flash irradiation for 10 s at 100 A degrees C was the best process to efficiently extract PC and APC, as it combined a high temperature necessary...
Tipo: Text
Palavras-chave: Allophycocyanin; MAE; Microalgae; Microwave; Phycobiliprotein; Phycocyanin; Phycoerythrin; Porphyridium; Thylakoid.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00253/36439/35169.pdf

Enhancement of neutral lipid productivity in the microalga Isochrysis affinis Galbana (T-Iso) by a mutation-selection procedure
Provedor de dados: 5
Autores: 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