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| Registros recuperados: 38 | |
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| 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 |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00304/41518/40726.pdf |
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| Bonnefond, Hubert; Grimaud, Ghjuvan; Rumin, Judith; Bougaran, Gael; Talec, Amelie; Gachelin, Manon; Boutoute, Marc; Pruvost, Eric; Bernard, Olivier; Sciandra, Antoine. |
| Temperature plays a key role in outdoor industrial cultivation of microalgae. Improving the thermal tolerance of microalgae to both daily and seasonal temperature fluctuations can thus contribute to increase their annual productivity. A long term selection experiment was carried out to increase the thermal niche (temperature range for which the growth is possible) of a neutral lipid overproducing strain of Tisochrysis lutea. The experimental protocol consisted to submit cells to daily variations of temperature for 7 months. The stress intensity, defined as the amplitude of daily temperature variations, was progressively increased along successive selection cycles. Only the amplitude of the temperature variations were increased, the daily average... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00404/51506/52107.pdf |
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| Bougaran, Gael. |
| Interactions between nitrogen (N) and phosphorus (P) on the growth of phytoplankton are not fully elucidated. Here, we propose the hypothesis that, since phosphorus plays a central role in energy, it can control the active transport of NO3. Our model for N-P co-limitation provides an asymmetric structure which reflects the respective roles of both nutrients and the differences in the control of absorption. The model succeeds in describing the different trends observed for N and P cell content in data sets taken from the literature. We further conducted experiments in batch and chemostat under different N: P ratios. Our results highlighted that P-limited cells were characterized by a low content of ATP and a low net absorption of NO3. When PO4 was... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00293/40397/38912.pdf |
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| Bougaran, Gael; Bernard, Olivier; Sciandra, Antoine. |
| It is well documented that the combination of low nitrogen and phosphorus resources can lead to situations where colimitation of phytoplankton growth arises, yet the underlying mechanisms are not fully understood. Here, we propose a Droop-based model built on the idea that colimitation by nitrogen and phosphorus arises from the uptake of nitrogen. Indeed, since N-porters are active systems, they require energy that could be related to the phosphorus status of the cell. Therefore, we assumed that N uptake is enhanced by the P quota. Our model also accounts for the biological observations that uptake of a nutrient can be down-regulated by its own internal quota, and succeeds in describing the strong contrast for the non-limiting quotas under N-limited and... |
| Tipo: Text |
Palavras-chave: Colimitation; Phytoplankton; Mathematical model; Quota. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00011/12216/9060.pdf |
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| 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 |
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| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00304/41519/40727.pdf |
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| 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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| 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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| 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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| Bougaran, Gael; Saint-jean, Bruno. |
| Pour nos sociétés modernes, en quête de nouveaux procédés et de molécules actives innovantes, les microalgues représentent un formidable potentiel. Leurs nombreuses espèces et leur biodiversité constituent un réservoir de métabolites et de propriétés biochimiques quasi-inexploré, pour le développement de nouvelles applications biotechnologiques. |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00252/36321/34885.pdf |
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| Carrier, Gregory; Baroukh, Caroline; Rouxel, Catherine; Duboscq-bidot, Laetitia; Schreiber, Nathalie; Bougaran, Gael. |
| Tisochrysis lutea is a microalga species currently used in aquaculture as a feed for shellfish, oysters and shrimps. It also has many other potential industrial applications, such as the production of neutral lipids for biofuels or the production of ω-3 fatty acids for nutraceuticals (human food complements). To efficiently exploit the potential of this microalga, however, higher lipid productivities are needed. To this end, improvement programs need to be developed and optimized. The diversity of strains available in microalgae has not yet been exploited in such improvement programs. In this study, the intra-strain diversity was observed and exploited to increase neutral lipid productivity. New clonal strains with higher neutral lipid productivity were... |
| Tipo: Text |
Palavras-chave: Microalgae; Genome; Improvement program; Lipids; Tisochrysis lutea. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00411/52204/52927.pdf |
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| Carrier, Gregory; Garnier, Matthieu; Le Cunff, Loic; Bougaran, Gael; Probert, Ian; De Vargas, Colomban; Corre, E; Cadoret, Jean-paul; Saint-jean, Bruno. |
| The applied exploitation of microalgae cultures has to date almost exclusively involved the use of wild type strains, deposited over decades in dedicated culture collections. Concomitantly, the concept of improving algae with selection programs for particular specific purposes is slowly emerging. Studying since a decade an economically and ecologically important haptophyte Tisochrysis lutea (Tiso), we took advantage of the availability of wild type (Tiso-Wt) and selected (Tiso-S2M2) strains to conduct a molecular variations study. This endeavour presented substantial challenges: the genome assembly was not yet available, the life cycle unknown and genetic diversity of Tiso-Wt poorly documented. This study brings the first molecular data in order to set up... |
| Tipo: Text |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00175/28662/27089.pdf |
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| 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... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00253/36467/35044.pdf |
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| Cointet, Eva; Wielgosz-collin, Gaëtane; Bougaran, Gael; Rabesaotra, Vony; Gonçalves, Olivier; Méléder, Vona. |
| Microalgal biotechnology has gained considerable importance in recent decades. Applications range from simple biomass production for food and animal feed to valuable products for fuel, pharmaceuticals, health, biomolecules and materials relevant to nanotechnology. There are few reports of the exploration of wider microalgae biodiversity in the literature on high value microalgal compounds, however, because it is believed that there is little to be gained in terms of biomass productivity by examining new strains. Still, without diversity, innovation in biotechnology applications is currently limited. Using microalgal diversity is a very promising way to match species and processes for a specific biotechnological application. In this context, three benthic... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00591/70269/68328.pdf |
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| Da Costa, F.; Petton, Bruno; Mingant, Christian; Bougaran, Gael; Rouxel, Catherine; Quere, Claudie; Wikfors, G. H.; Soudant, P.; Robert, Rene. |
| Effects of a remarkably high overall lipid Tisochrysis lutea strain (T+) upon gross biochemical composition, fatty acid (FA), sterol and lipid class composition of Crassostrea gigas larvae were evaluated and compared with a normal strain of Tisochrysis lutea (T) and the diatom Chaetoceros neogracile (Cg). In a first experiment, the influence of different single diets (T, T+ and Cg) and a bispecific diet (TCg) was studied, whereas, effects of monospecific diets (T and T+) and bispecific diets (TCg and T+Cg) were evaluated in a second experiment. The strain T+ was very rich in triglycerides (TAG: 93–95% of total neutral lipids), saturated FA (45%), monounsaturated FA (31–33%) and total fatty acids (4.0–4.7 pg cell−1). Larval oyster survival and growth rate... |
| Tipo: Text |
Palavras-chave: Larvae; Lipids; Oyster; Tisochrysis lutea. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00251/36258/36063.pdf |
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| 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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| Gaillard, Sylvain; Charrier, Aurelie; Malo, Florent; Carpentier, Liliane; Bougaran, Gael; Hégaret, Helene; Réveillon, Damien; Hess, Philipp; Séchet, Veronique. |
| The cryptophyte Teleaulax amphioxeia is a source of plastids for the ciliate Mesodinium rubrum and both organisms are members of the trophic chain of several species of Dinophysis. It is important to better understand the ecology of organisms at the first trophic levels before assessing the impact of principal factors of global change on Dinophysis spp. Therefore, combined effects of temperature, irradiance and pH on growth rate, photosynthetic activity and pigment content of a temperate strain of T. amphioxeia were studied using a full factorial design (central composite design 23*) in 17 individually controlled bioreactors. The derived model predicted an optimal growth rate of T. amphioxeia at a light intensity of 400 µmol photons · m‐2 · s‐1, more... |
| Tipo: Text |
Palavras-chave: Dinophysis; Ecophysiology; Full factorial design; Global change; Mesodinium rubrum; Teleaulax amphioxeia. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72155/70910.pdf |
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| 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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| Garnier, Matthieu; Carrier, Gregory; Rogniaux, Helene; Nicolau, Elodie; Bougaran, Gael; Saint-jean, Bruno; Cadoret, Jean-paul. |
| Microalgae are photosynthetic microorganisms that have an extraordinary diversity which biotechnological potential is just beginning to be explored. Microalgae in biotechnology are presently the focus of an unprecedented surge in interest and investment worldwide. Understanding microalgal lipid accumulation under nitrogen starvation is of major interest for feedstocks, food and biofuel production. Although studies have been performed in model species, to this day it is critical to understand through particular mechanisms of biotechnological species. Tisochrysis lutea is traditionally used for aquaculture feed and presents advantages for lipid production. The wild type strain and a lipid over-accumulating selected mutant were used to perform the first... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00176/28735/27203.pdf |
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| Garnier, Matthieu; Carrier, Gregory; Rogniaux, Helene; Nicolau, Elodie; Bougaran, Gael; Saint-jean, Bruno; Cadoret, Jean-paul. |
| Understanding microalgal lipid accumulation under nitrogen starvation is of major interest for biomass feedstock, food and biofuel production. Using a domesticated oleaginous algae Tisochrysis lutea, we performed the first comparative proteomic analysis on the wild type strain and a selected lipid over-accumulating mutant. 2-DE analysis was made on these strains cultured in two metabolic conditions, with and without nitrogen deprivation, which revealed significant differences in proteomes according to both strain and nitrogen availability. Mass spectrometry allowed us to identify 37 proteins that were differentially expressed between the two strains, and 17 proteins regulated by nitrogen starvation concomitantly with lipid accumulation. The proteins... |
| Tipo: Text |
Palavras-chave: Microalgae; Biotechnology; Lipid; Nitrogen; Proteomic; Selection. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00179/29012/27470.pdf |
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| Registros recuperados: 38 | |
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