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Carbon Orientation in the Diatom Phaeodactylum tricornutum: The Effects of Carbon Limitation and Photon Flux Density ArchiMer
Heydarizadeh, Parisa; Veidi, Brigitte; Huang, Bing; Lukomska, Ewa; Wielgosz-collin, Gaetane; Couzinet-mossion, Aurélie; Bougaran, Gael; Marchand, Justine; Schoefs, Benoit.
Diatoms adapt to changing environmental conditions in very efficient ways. Among the mechanisms that can be activated, the reorientation of carbon metabolism is crucial because it allows the storage of energy into energy-dense molecules, typically lipids. Beside their roles in physiology, lipids are commercially interesting compounds. Therefore studies dealing with this topic are relevant for both basic and applied science. Although the molecular mechanisms involved in the reorientation of carbon metabolism as a response to a deficiency in nutrients such as nitrogen or phosphorus has been partially elucidated, the impacts of carbon availability on the implementation of the reorientation mechanisms remain unclear. Indeed, it has not been determined if the...
Tipo: Text Palavras-chave: Diatom; Carbon deficiency; Carbon metabolism; Stress; Light intensity; Regulation; Biotechnology; Phosphoenolpyruvate.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00489/60058/63338.pdf
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Contribution aux essais d'addition des cryoprotecteurs dans la pulpe de poisson ArchiMer
Lukomska, Ewa.
Le sujet de ce travail est l'étude des combinaisons de cryoprotecteurs dans la pulpe à partir des arêtes centrales de cabillaud. Dans une seconde partie le comportement d'une combinaison de cryoprotecteurs en présence de' certains pourcentages de reins sera plus particulièrement étudié.
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Ano: 1985 URL: http://archimer.ifremer.fr/doc/00119/22986/20818.pdf
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Culture en continu de Isochrysis galbana affinis Tahiti ArchiMer
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...
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Ano: 2001 URL: http://archimer.ifremer.fr/doc/00304/41508/40716.pdf
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Effects of blue light on the biochemical composition and photosynthetic activity of Isochrysis sp. (T-iso) ArchiMer
Marchetti, Julie; Bougaran, Gael; Jauffrais, Thierry; Lefebvre, Sebastien; Rouxel, Catherine; Saint-jean, Bruno; Lukomska, Ewa; Robert, Rene; Cadoret, Jean-paul.
In aquaculture, particularly in bivalve hatcheries, the biochemical composition of algal diets has a strong influence on larval and post-larval development. Biochemical composition is known to be related to culture conditions, among which light represents a major source of variation. The effects of blue light on biochemical composition and photosynthetic rate of Isochrysis sp. (T-iso) CCAP 927/14 were assessed in chemostat at a single irradiance (300 μmol photons m−2 s−1) and compared with white light. Two different dilution (renewal) rates were also tested: 0.7 and 0.2 d−1. Relative carbohydrate content was lower under blue light than under white light at both dilution rates, whereas chlorophyll a and photosynthesis activity were higher. In contrast,...
Tipo: Text Palavras-chave: Isochrysis; Blue light; Photosynthesis; Proximate composition; Chemostat.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00085/19599/17237.pdf
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Effects of nitrogen limitation on Dunaliella sp.–Alteromonas sp. interactions: from mutualistic to competitive relationships. ArchiMer
Le Chevanton, Myriam; Garnier, Matthieu; Lukomska, Ewa; Schreiber, Nathalie; Cadoret, Jean-paul; Saint-jean, Bruno; Bougaran, Gael.
Interactions between photosynthetic and non-photosynthetic microorganisms play an essential role in natural aquatic environments and the contribution of bacteria and microalgae to the nitrogen cycle can lead to both competitive and mutualistic relationships. Nitrogen is considered to be, with phosphorus and iron, one of the main limiting nutrients for primary production in the oceans and its availability experiences large temporal and geographical variations. For these reasons, it is important to understand how competitive and mutualistic interactions between photosynthetic and heterotrophic microorganisms are impacted by nitrogen limitation. In a previous study performed in batch cultures, the addition of a selected bacterial strain of Alteromonas sp....
Tipo: Text Palavras-chave: Interactions; Nitrogen limitation; Microalgae; Bacteria; Chemostat; Dissolved organic matter (DOM); Dunaliella.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00344/45529/45087.pdf
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Enhancement of neutral lipid productivity in the microalga Isochrysis affinis Galbana (T-Iso) by a mutation-selection procedure ArchiMer
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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High-affinity nitrate/nitrite transporter genes (Nrt2) in Tisochrysis lutea: identification and expression analyses reveal some interesting specificities of Haptophyta microalgae ArchiMer
Charrier, Aurelie Georgette; Berard, Jean-baptiste; Bougaran, Gael; Carrier, Gregory; Lukomska, Ewa; Schreiber, Nathalie; Fournier, Flora; Charrier, Aurelie; Rouxel, Catherine; Garnier, Matthieu; Cadoret, Jean-paul; Saint-jean, Bruno.
Microalgae have a diversity of industrial applications such as feed, food ingredients, depuration processes and energy. However, microalgal production costs could be substantially improved by controlling nutrient intake. Accordingly, a better understanding of microalgal nitrogen metabolism is essential. Using in silico analysis from transcriptomic data concerning the microalgae Tisochrysis lutea, four genes encoding putative high-affinity nitrate/nitrite transporters (TlNrt2) were identified. Unlike most of the land plants and microalgae, cloning of genomic sequences and their alignment with complementary DNA (cDNA) sequences did not reveal the presence of introns in all TlNrt2 genes. The deduced TlNRT2 protein sequences showed similarities to NRT2...
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Ano: 2015 URL: https://archimer.ifremer.fr/doc/00253/36467/35044.pdf
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Nitrogen and phosphorus limitations induce carbon partitioning and membrane lipid remodelling in the marine diatom Phaeodactylum tricornutum ArchiMer
Huang, Bing; Marchand, Justine; Blanckaert, Vincent; Lukomska, Ewa; Ulmann, Lionel; Wielgosz-collin, Gaëtane; Rabesaotra, Vony; Moreau, Brigitte; Bougaran, Gael; Mimouni, Virginie; Morant-manceau, Annick.
Nitrogen (N) and phosphorus (P) limitations induce triacylglycerol (TAG) accumulation and membrane lipid remodelling in the marine diatom Phaeodactylum tricornutum. However, a clear understanding of the metabolic reorientation is still lacking. Carbon partitioning is of great interest because this microalga produces various highly valuable molecules such as lipids and polyunsaturated fatty acids. This study compared growth, photosynthetic activity, biochemical and transcriptional responses of P. tricornutum throughout batch culture under N or P limitation. The integrated results show that the photosynthetic intensity was greatly reduced under N or P limitation. Under N limitation, the degradation and re-use of cellular N-containing compounds contributed to...
Tipo: Text Palavras-chave: Betaine lipid; Lipid remodelling; Microalga; Nitrogen; Phosphorus; Polyunsaturated fatty acid.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00491/60249/63861.pdf
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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 ArchiMer
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.
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Ano: 2007 URL: http://archimer.ifremer.fr/doc/00304/41518/40726.pdf
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Optimisation de l'enrichissement nutritif pour la culture d' Isochrysis galbana affinis Tahiti ArchiMer
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...
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Ano: 2001 URL: http://archimer.ifremer.fr/doc/00304/41519/40727.pdf
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Optimizing conditions for the continuous culture of Isochrysis affinis galbana relevant to commercial hatcheries ArchiMer
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
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Response of CO2-starved diatom Phaeodactylum tricornutum to light intensity transition ArchiMer
Heydarizadeh, Parisa; Boureba, Wafaa; Zahedi, Morteza; Huang, Bing; Moreau, Brigitte; Lukomska, Ewa; Couzinet-mossion, Aurelie; Wielgosz-collin, Gaetane; Martin-jezequel, Veronique; Bougaran, Gael; Marchand, Justine; Schoefs, Benoit.
In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 mu mol m(-2) s(-1) photon flux density to an increase (1000 mmol m(-2) s(-1)) or decrease (30 mmol m(-2)s(-1)) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins...
Tipo: Text Palavras-chave: Phaeodactylum tricornutum; Carbon metabolism; Light regulation; Photosynthesis; Chlorophyll fluorescence; Pyruvate hub.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00395/50620/52341.pdf
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Screening and selection of growth-promoting bacteria for Dunaliella cultures ArchiMer
Le Chevanton, Myriam; Garnier, Matthieu; Bougaran, Gael; Schreiber, Nathalie; Lukomska, Ewa; Berard, Jean-baptiste; Fouilland, E.; Bernard, Olivier; Cadoret, Jean-paul.
Previous studies have demonstrated that bacteria influence microalgal metabolism, suggesting that the selection and characterization of growth-promoting bacteria should offer a new strategy for improving industrial algal cultivation. In the present study, 48 cultivable bacteria were isolated from marine microalgae species and identified using 16S rRNA phylogenetic analysis. The recovered bacteria were found to be members of the α- and γ-Proteobacteria, Cytophaga–Flavobacterium–Bacteroides (CFB) and gram-positive monophyletic clusters. To address the effect of these bacteria on the growth of Dunaliella sp. individually, an experimental high-throughput tool was developed to simultaneously compare replicated associations. A two-step approach was used to...
Tipo: Text Palavras-chave: Microalgae; Dunaliella; Bacteria; Interaction; Bacterial diversity.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00142/25334/24768.pdf
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Transient initial phase in continuous culture of Isochrysis galbana affinis Tahiti ArchiMer
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
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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: https://archimer.ifremer.fr/doc/00356/46702/46904.pdf
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