Search

Your search keyword '"Talec, A."' showing total 386 results
Start Over Author "Talec, A."
386 results on '"Talec, A."'

2. Hydrocortisone plus fludrocortisone for community acquired pneumonia-related septic shock: a subgroup analysis of the APROCCHSS phase 3 randomised trial

Author

Djillali, ANNANE, Christian, BRUN-BUISSON, Benoit, MISSET, Jean, CHASTRE, François, BRIVET, Julien, BOHE, Carole, SCHWEBEL, Shidasp, SIAMI, Michel, SLAMA, Olivier, LEROY, Gilles, CAPELLIER, Michel, WOLFF, Mohamed, ALI BEN ALI, François, ANTONINI, Jean-François, LORIFERNE, Franck, PETITPAS, Claire, CHARPENTIER, Jean-Michel, CONSTANTIN, Gilles, D'HONNEUR, Bertrand, SOUWEINE, Xavier, FORCEVILLE, Bruno, MEGARBANE, Francois, BAUDIN, Gwenhaël, COLIN, Karim, ASEHNOUNE, Jean-Pierre, QUENOT, Bruno, FRANCOIS, Thierry, BOULAIN, Emmanuelle, MERCIER, Jean, REIGNIER, Roland, AMATHIEU, Fabrice, COOK, Alain, CARIOU, Loic, CHIMOT, Fouad, Fadel, Andrea, Polito, Bernard, Clair, Virginie, Maxime, David, Luis, Tarek, Sharshar, David, Orlikowski, Keyvan, RAZAZI, Nicolas, DE PROST, Guillaume, CARTEAUX, Maité, GARROUSTE ORGEAS, François, Philippart, Alain, Combes, Ania, Nieszkowska, Frederic, Jacobs, Dominique, Prat, Patrick, Lafforgue, Claire, ARA SOMOHANO, Clémence, MINET, Maxime, LUGOSI, Julien, Maizel, Jean Christophe, Navellou, Bruno, Mourvillier, Lila, Bouadma, Jean François, Timsit, Claude Denis, Martin, Julien, Textoris, Sandrine, Wiramus, Clément, BRUN, Benoît, RAGONNET, Ali, Ait-Hssain, Samia, Touati, Jean, Kuba, Vincent, Willems, Pierre, Lahillaire, Mohammed, Lassi, Marion, ANTONA, Alia, MEGHENEM, Marine, DEMESMAY, Eric, Boulet, Olivier, LOUTREL, Romain, DUMONT, Antoine, ROQUILLY, Pierre-Joachim, MAHE, Dominique, DEMEURE dit LATTE, Philippe, CHAMPIN, Jean François, ARNOULD, Raphaël, CINOTTI, Ronan, Le FLOCH, Marc, Clavel, Philippe, Vignon, Nicolas, Pichon, Emmanuelle, BEGOT, Anne-Laure, FEDOU, Catherine, CHAPELLAS, Antoine, GALY, Dalila, Benzekri Lefevre, Armelle, Mathonnet, Anne, Bretagnol, Isabelle, Runge, François, BARBIER, Grégoire, MULLER, Denis, GAROT, Pierre François, DEQUIN, Dominique, PERROTIN, Annick, LEGRAS, Julie, MANKIKIAN, Patrice, TALEC, Stephan, EHRMANN, Aurélie, JORET, Claire, LHOMMET, Emmanuelle, ROUVE, Laetitia, BODET-CONTENTIN, Youenn, JOUAN, Charlotte, SALMONGANDONNIERE, Laurent, MARTIN-LEFEVRE, Matthieu, HENRY-LAGARRIGUE, Aihem, YEHIA, Jean-Baptiste, LASCARROU, Christine, LEBERT, Jean-Claude, LACHERADE, Eric, LEVESQUE, Yen-Lan, NGUYEN, Fabrice, DAVIAUD, Adrien, BOUGLE, Jean Paul, MIRA, Jean Daniel, CHICHE, Frederic, PENE, Tristan, MORICHAU-BEAUCHANT, Guillaume, GERI, Pierre Henri, DESSALLES, Yannick, MONSEAU, Mélanie, SAINT-LEGER, Sandrine, BEDON-CARTE, Laetitia, Bodet-Contentin, Walid, Darwiche, Stephan, Ehrmann, Denis, Garot, Antoine, Guillon, Youenn, Jouan, Annick, Legras, Julie, Mankikian, Emmanuelle, Mercier, Marlene, Morisseau, Yonatan, Perez, Emmanuelle, Rouve, Charlotte, Salmon-Gandonniere, Julie, Helms, Hassene, Rahmani, Alexandra, Monnier, Hamid, Merdji, Raphael, Clere-Jehl, Laure, Stiel, Antoine, Studer, Pascal, Andreu, Jean-Baptiste, Roudaut, Marie, Labruyere, Marine, Jacquier, Francois, Barbier, Dalila, Benzekri, Thierry, Boulain, Sophie, Jacquier, Gregoire, Muller, Mai-Anh, Nai, Sophie, Tollec, Damien, Roux, Jonathan, Messika, Constance, Vuillard, Louis-Marie, Dumont, Laura, Federici, Noemie, Zucman, Marc, Amouretti, Djillali, Annane, Pierre, Moine, Paris, Meng, Rania, Bounab, Muriel-Sarah, Fartoukh, Michel, Djibre, Alexandre, Elabbadi, Marie-Ange, Azais, Konstantinos, Bachoumas, Arthur, Bailly, Remi, Bernardon, Gauthier, Blonz, Luc, Desmedt, Brian, Emonet, Maud, Fiancette, Matthieu, Henry, Jean-Claude, Lacherade, Jean-Baptiste, Lascarrou, Christine, Lebert, Julien, Lorber, Laurent Martin-, Lefevre, Caroline, Pouplet, Isabelle, Vinatier, Aihem, Yehia, Sarah, Benghanem, Julien, Charpentier, Clara, Vigneron, Anne-Laure, Fedou, Claire, Mancia, Emmanuelle, Begot, Thomas, Daix, Antoine, Galy, Celine, Gonzalez, Marine, Goudelin, Bruno, Evrard, Arnaud, Desachy, Julien, Vaidie, Guillaume, Gilbert, Cedric, Darreau, Benoit, Derrien, Marjorie, Saint-Martin, Patrice, Tirot, Mickael, Landais, Nicolas, Chudeau, Jean Christophe, Callahan, Dominique, Vivier, Charlene, Le Moal, Pierre-Yves, Olivier, Remy, Marnai, Francis, Schneider, Nicolas, Sedillot, Xavier, Tchenio, Adrien, Robine, Yves, Poncelin, Remi, Bruyere, Heming, Nicholas, Renault, Alain, Kuperminc, Emmanuelle, Brun-Buisson, Christian, Megarbane, Bruno, Quenot, Jean-Pierre, Siami, Shidasp, Cariou, Alain, Forceville, Xavier, Schwebel, Carole, Leone, Marc, Timsit, Jean-Francois, Misset, Benoît, Benali, Mohamed Ali, Colin, Gwenhael, Souweine, Bertrand, Asehnoune, Karim, Mercier, Emmanuelle, Chimot, Loïc, Charpentier, Claire, François, Bruno, Boulain, Thierry, Petitpas, Frank, Constantin, Jean Michel, Dhonneur, Gilles, Baudin, François, Combes, Alain, Bohé, Julien, Loriferne, Jean-François, Cook, Fabrice, Slama, Michel, Leroy, Olivier, Capellier, Gilles, Dargent, Auguste, Hissem, Tarik, Bounab, Rania, Maxime, Virginie, Moine, Pierre, Bellissant, Eric, and Annane, Djillali

Published
2024
Full Text
View/download PDF

3. Relying on pulse oximetry to avoid hypoxaemia and hyperoxia: A multicentre prospective cohort study in patients with circulatory failure

Author

Baudin, Olivier, Calvat, Sylvie, Cracco, Christophe, Desachy, Arnault, Lafon, Charles, Boitrou, Emmanuelle, Follin, Arnaud, Mentec, Hervé, Pajot, Olivier, Plantefève, Gaëtan, Thirion, Marina, Bruyère, Rémi, Quenot, Jean-Pierre, Bachoumas, Konstantinos, Fiancette, Maud, Lacherade, Jean Claude, Lebert, Christine, Martin-Lefèvre, Laurent, Reignier, Jean, Vinatier, Isabelle, Yehia, Aihem, Begot, Emmanuelle, Bellier, Remy, Clavel, Marc, François, Bruno, Galy, Antoine, Pichon, Nicolas, Bardou, Patrick, Bellec, Frédéric, Bonnivard, Michel, Marco, Anne, Roustan, Jérôme, Vimeux, Sylvie, Bretagnol, Anne, Mathonnet, Armelle, Bercault, Nicolas, Kamel, Toufik, Muller, Grégoire, Réminiac, François, Runge, Isabelle, Skarzynski, Marie, Chatellier, Delphine, Coudroy, Rémi, Frat, Jean-Pierre, Goudet, Véronique, Robert, René, Veinstein, Anne, Botoc, Vlad, Chevalier, Stéphanie, Collet, François, Gouello, Jean-Paul, Badin, Julie, Guillon, Antoine, Legras, Annick, Masseret, Elodie, Mercier, Emmanuelle, Talec, Patrice, Boulain, Thierry, Nay, Mai-Anh, Dequin, Pierre-François, Lascarrou, Jean-Baptiste, Vignon, Philippe, and Ehrmann, Stephan

Published
2023
Full Text
View/download PDF

9. Hydrocortisone plus fludrocortisone for community acquired pneumonia-related septic shock: a subgroup analysis of the APROCCHSS phase 3 randomised trial

Author

Heming, Nicholas, primary, Renault, Alain, additional, Kuperminc, Emmanuelle, additional, Brun-Buisson, Christian, additional, Megarbane, Bruno, additional, Quenot, Jean-Pierre, additional, Siami, Shidasp, additional, Cariou, Alain, additional, Forceville, Xavier, additional, Schwebel, Carole, additional, Leone, Marc, additional, Timsit, Jean-Francois, additional, Misset, Benoît, additional, Benali, Mohamed Ali, additional, Colin, Gwenhael, additional, Souweine, Bertrand, additional, Asehnoune, Karim, additional, Mercier, Emmanuelle, additional, Chimot, Loïc, additional, Charpentier, Claire, additional, François, Bruno, additional, Boulain, Thierry, additional, Petitpas, Frank, additional, Constantin, Jean Michel, additional, Dhonneur, Gilles, additional, Baudin, François, additional, Combes, Alain, additional, Bohé, Julien, additional, Loriferne, Jean-François, additional, Cook, Fabrice, additional, Slama, Michel, additional, Leroy, Olivier, additional, Capellier, Gilles, additional, Dargent, Auguste, additional, Hissem, Tarik, additional, Bounab, Rania, additional, Maxime, Virginie, additional, Moine, Pierre, additional, Bellissant, Eric, additional, Annane, Djillali, additional, Djillali, ANNANE, additional, Christian, BRUN-BUISSON, additional, Benoit, MISSET, additional, Jean, CHASTRE, additional, François, BRIVET, additional, Julien, BOHE, additional, Carole, SCHWEBEL, additional, Shidasp, SIAMI, additional, Michel, SLAMA, additional, Olivier, LEROY, additional, Gilles, CAPELLIER, additional, Michel, WOLFF, additional, Mohamed, ALI BEN ALI, additional, François, ANTONINI, additional, Jean-François, LORIFERNE, additional, Franck, PETITPAS, additional, Claire, CHARPENTIER, additional, Jean-Michel, CONSTANTIN, additional, Gilles, D'HONNEUR, additional, Bertrand, SOUWEINE, additional, Xavier, FORCEVILLE, additional, Bruno, MEGARBANE, additional, Francois, BAUDIN, additional, Gwenhaël, COLIN, additional, Karim, ASEHNOUNE, additional, Jean-Pierre, QUENOT, additional, Bruno, FRANCOIS, additional, Thierry, BOULAIN, additional, Emmanuelle, MERCIER, additional, Jean, REIGNIER, additional, Roland, AMATHIEU, additional, Fabrice, COOK, additional, Alain, CARIOU, additional, Loic, CHIMOT, additional, Fouad, Fadel, additional, Andrea, Polito, additional, Bernard, Clair, additional, Virginie, Maxime, additional, David, Luis, additional, Tarek, Sharshar, additional, David, Orlikowski, additional, Keyvan, RAZAZI, additional, Nicolas, DE PROST, additional, Guillaume, CARTEAUX, additional, Maité, GARROUSTE ORGEAS, additional, François, Philippart, additional, Alain, Combes, additional, Ania, Nieszkowska, additional, Frederic, Jacobs, additional, Dominique, Prat, additional, Patrick, Lafforgue, additional, Claire, ARA SOMOHANO, additional, Clémence, MINET, additional, Maxime, LUGOSI, additional, Julien, Maizel, additional, Jean Christophe, Navellou, additional, Bruno, Mourvillier, additional, Lila, Bouadma, additional, Jean François, Timsit, additional, Claude Denis, Martin, additional, Julien, Textoris, additional, Sandrine, Wiramus, additional, Clément, BRUN, additional, Benoît, RAGONNET, additional, Ali, Ait-Hssain, additional, Samia, Touati, additional, Jean, Kuba, additional, Vincent, Willems, additional, Pierre, Lahillaire, additional, Mohammed, Lassi, additional, Marion, ANTONA, additional, Alia, MEGHENEM, additional, Marine, DEMESMAY, additional, Eric, Boulet, additional, Olivier, LOUTREL, additional, Romain, DUMONT, additional, Antoine, ROQUILLY, additional, Pierre-Joachim, MAHE, additional, Dominique, DEMEURE dit LATTE, additional, Philippe, CHAMPIN, additional, Jean François, ARNOULD, additional, Raphaël, CINOTTI, additional, Ronan, Le FLOCH, additional, Marc, Clavel, additional, Philippe, Vignon, additional, Nicolas, Pichon, additional, Emmanuelle, BEGOT, additional, Anne-Laure, FEDOU, additional, Catherine, CHAPELLAS, additional, Antoine, GALY, additional, Dalila, Benzekri Lefevre, additional, Armelle, Mathonnet, additional, Anne, Bretagnol, additional, Isabelle, Runge, additional, François, BARBIER, additional, Grégoire, MULLER, additional, Denis, GAROT, additional, Pierre François, DEQUIN, additional, Dominique, PERROTIN, additional, Annick, LEGRAS, additional, Julie, MANKIKIAN, additional, Patrice, TALEC, additional, Stephan, EHRMANN, additional, Aurélie, JORET, additional, Claire, LHOMMET, additional, Emmanuelle, ROUVE, additional, Laetitia, BODET-CONTENTIN, additional, Youenn, JOUAN, additional, Charlotte, SALMONGANDONNIERE, additional, Laurent, MARTIN-LEFEVRE, additional, Matthieu, HENRY-LAGARRIGUE, additional, Aihem, YEHIA, additional, Jean-Baptiste, LASCARROU, additional, Christine, LEBERT, additional, Jean-Claude, LACHERADE, additional, Eric, LEVESQUE, additional, Yen-Lan, NGUYEN, additional, Fabrice, DAVIAUD, additional, Adrien, BOUGLE, additional, Jean Paul, MIRA, additional, Jean Daniel, CHICHE, additional, Frederic, PENE, additional, Tristan, MORICHAU-BEAUCHANT, additional, Guillaume, GERI, additional, Pierre Henri, DESSALLES, additional, Yannick, MONSEAU, additional, Mélanie, SAINT-LEGER, additional, Sandrine, BEDON-CARTE, additional, Laetitia, Bodet-Contentin, additional, Walid, Darwiche, additional, Stephan, Ehrmann, additional, Denis, Garot, additional, Antoine, Guillon, additional, Youenn, Jouan, additional, Annick, Legras, additional, Julie, Mankikian, additional, Emmanuelle, Mercier, additional, Marlene, Morisseau, additional, Yonatan, Perez, additional, Emmanuelle, Rouve, additional, Charlotte, Salmon-Gandonniere, additional, Julie, Helms, additional, Hassene, Rahmani, additional, Alexandra, Monnier, additional, Hamid, Merdji, additional, Raphael, Clere-Jehl, additional, Laure, Stiel, additional, Antoine, Studer, additional, Pascal, Andreu, additional, Jean-Baptiste, Roudaut, additional, Marie, Labruyere, additional, Marine, Jacquier, additional, Francois, Barbier, additional, Dalila, Benzekri, additional, Thierry, Boulain, additional, Sophie, Jacquier, additional, Gregoire, Muller, additional, Mai-Anh, Nai, additional, Sophie, Tollec, additional, Damien, Roux, additional, Jonathan, Messika, additional, Constance, Vuillard, additional, Louis-Marie, Dumont, additional, Laura, Federici, additional, Noemie, Zucman, additional, Marc, Amouretti, additional, Djillali, Annane, additional, Pierre, Moine, additional, Paris, Meng, additional, Rania, Bounab, additional, Muriel-Sarah, Fartoukh, additional, Michel, Djibre, additional, Alexandre, Elabbadi, additional, Marie-Ange, Azais, additional, Konstantinos, Bachoumas, additional, Arthur, Bailly, additional, Remi, Bernardon, additional, Gauthier, Blonz, additional, Luc, Desmedt, additional, Brian, Emonet, additional, Maud, Fiancette, additional, Matthieu, Henry, additional, Jean-Claude, Lacherade, additional, Jean-Baptiste, Lascarrou, additional, Christine, Lebert, additional, Julien, Lorber, additional, Laurent Martin-, Lefevre, additional, Caroline, Pouplet, additional, Isabelle, Vinatier, additional, Aihem, Yehia, additional, Sarah, Benghanem, additional, Julien, Charpentier, additional, Clara, Vigneron, additional, Anne-Laure, Fedou, additional, Claire, Mancia, additional, Emmanuelle, Begot, additional, Thomas, Daix, additional, Antoine, Galy, additional, Celine, Gonzalez, additional, Marine, Goudelin, additional, Bruno, Evrard, additional, Arnaud, Desachy, additional, Julien, Vaidie, additional, Guillaume, Gilbert, additional, Cedric, Darreau, additional, Benoit, Derrien, additional, Marjorie, Saint-Martin, additional, Patrice, Tirot, additional, Mickael, Landais, additional, Nicolas, Chudeau, additional, Jean Christophe, Callahan, additional, Dominique, Vivier, additional, Charlene, Le Moal, additional, Pierre-Yves, Olivier, additional, Remy, Marnai, additional, Francis, Schneider, additional, Nicolas, Sedillot, additional, Xavier, Tchenio, additional, Adrien, Robine, additional, Yves, Poncelin, additional, and Remi, Bruyere, additional

Published
2024
Full Text
View/download PDF

10. Organic Phosphorus Scavenging Supports Efficient Growth of Diazotrophic Cyanobacteria Under Phosphate Depletion

Author

Sophie Rabouille, Lauralie Tournier, Solange Duhamel, Pascal Claquin, Olivier Crispi, Amélie Talec, Angela Landolfi, and Andreas Oschlies

Subjects
Crocosphaera watsonii, marine, oligotrophic, dissolved organic phosphorus, phosphonates, nitrogen fixation, Microbiology, QR1-502
Abstract

Considering the reported significant diazotrophic activities in open-ocean regions where primary production is strongly limited by phosphate, we explored the ability of diazotrophs to use other sources of phosphorus to alleviate the phosphate depletion. We tested the actual efficiency of the open-ocean, N2-fixer Crocosphaera watsonii to grow on organic phosphorus as the sole P source, and observed how the P source affects the cellular C, N, and P composition. We obtained equivalent growth efficiencies on AMP and DL-α-glycerophosphate as compared with identical cultures grown on phosphate, and survival of the population on phytic acid. Our results show that Crocosphaera cannot use all phosphomonoesters with the same efficiency, but it can grow without phosphate, provided that usable DOP and sufficient light energy are available. Also, results point out that organic phosphorus uptake is not proportional to alkaline phosphatase activity, demonstrating that the latter is not a suitable proxy to estimate DOP-based growth yields of organisms, whether in culture experiments or in the natural environment. The growth parameters obtained, as a function of the P source, will be critical to improve and calibrate mathematical models of diazotrophic growth and the distribution of nitrogen fixation in the global ocean.

Published
2022
Full Text
View/download PDF

13. High proportion of post-migration HIV acquisition in migrant men who have sex with men receiving HIV care in the Paris region, and associations with social disadvantage and sexual behaviours: results of the ANRS-MIE GANYMEDE study, France, 2021 to 2022.

Author

Palich, Romain, Arias-Rodríguez, Andrés, Duracinsky, Martin, Le Talec, Jean-Yves, Torrente, Olivia Rousset, Lascoux-Combe, Caroline, Lacombe, Karine, Ghosn, Jade, Viard, Jean-Paul, Pialoux, Gilles, Ohayon, Michel, Duvivier, Claudine, Velter, Annie, Mechlia, Mohamed Ben, Beniguel, Lydie, Grabar, Sophie, Melchior, Maria, Assoumou, Lambert, and Supervie, Virginie

Published
2024
Full Text
View/download PDF

14. Independence of a Marine Unicellular Diazotroph to the Presence of NO3−

Author

Sophie Rabouille, Benjamin Randall, Amélie Talec, Patrick Raimbault, Thierry Blasco, Amel Latifi, and Andreas Oschlies

Subjects
nitrogen fixation, marine cyanobacteria, nitrate uptake, Crocosphaera, Biology (General), QH301-705.5
Abstract

Marine nitrogen (N2) fixation was historically considered to be absent or reduced in nitrate (NO3−) rich environments. This is commonly attributed to the lower energetic cost of NO3− uptake compared to diazotrophy in oxic environments. This paradigm often contributes to making inferences about diazotroph distribution and activity in the ocean, and is also often used in biogeochemical ocean models. To assess the general validity of this paradigm beyond the traditionally used model organism Trichodesmium spp., we grew cultures of the unicellular cyanobacterium Crocosphaera watsonii WH8501 long term in medium containing replete concentrations of NO3−. NO3− uptake was measured in comparison to N2 fixation to assess the cultures’ nitrogen source preferences. We further measured culture growth rate, cell stoichiometry, and carbon fixation rate to determine if the presence of NO3− had any effect on cell metabolism. We found that uptake of NO3− by this strain of Crocosphaera was minimal in comparison to other N sources (~2–4% of total uptake). Furthermore, availability of NO3− did not statistically alter N2 fixation rate nor any aspect of cell physiology or metabolism measured (cellular growth rate, cell stoichiometry, cell size, nitrogen fixation rate, nitrogenase activity) in comparison to a NO3− free control culture. These results demonstrate the capability of a marine diazotroph to fix nitrogen and grow independently of NO3−. This lack of sensitivity of diazotrophy to NO3− suggests that assumptions often made about, and model formulations of, N2 fixation should be reconsidered.

Published
2021
Full Text
View/download PDF

20. Recueil des cartes de sensibilité et opérationnelles de l’Atlas POLMAR-Terre à La Réunion – mise à jour 2023

Author

Grondin, Evans, Duval, Magali, Talec, Pascal, Bouilly, Rémi, Grondin, Evans, Duval, Magali, Talec, Pascal, and Bouilly, Rémi

Abstract

Dans le cadre de la convention DEAL/IFREMER et pour le projet Atlas POLMAR-Terre, des mises à jour ponctuelles des couches géographiques dans l’outils SEXTANT sont nécessaires afin d’actualiser l’Atlas intéractif sur le site Polmar. Ces mises à jour nécessitent donc de modifier les produits de cartes de sensibilité et opérationnelles. Cette mise à jour fait suite à celle de 2016.

Published
2023
Full Text
View/download PDF

24. How do microalgae perceive light in a high-rate pond? Towards more realistic Lagrangian experiments

Author

David Demory, Charlotte Combe, Philipp Hartmann, Amélie Talec, Eric Pruvost, Raouf Hamouda, Fabien Souillé, Pierre-Olivier Lamare, Marie-Odile Bristeau, Jacques Sainte-Marie, Sophie Rabouille, Francis Mairet, Antoine Sciandra, and Olivier Bernard

Subjects
photosynthesis, hydrodynamics, modelling, photoacclimation, dunaliella salina, non-photochemical quenching, Science
Abstract

Hydrodynamics in a high-rate production reactor for microalgae cultivation affects the light history perceived by cells. The interplay between cell movement and medium turbidity leads to a complex light pattern, whose forcing effects on photosynthesis and photoacclimation dynamics are non-trivial. Hydrodynamics of high density algal ponds mixed by a paddle wheel has been studied recently, although the focus has never been on describing its impact on photosynthetic growth efficiency. In this multidisciplinary downscaling study, we first reconstructed single cell trajectories in an open raceway using an original hydrodynamical model offering a powerful discretization of the Navier–Stokes equations tailored to systems with free surfaces. The trajectory of a particular cell was selected and the associated high-frequency light pattern was computed. This light pattern was then experimentally reproduced in an Arduino-driven computer controlled cultivation system with a low density Dunaliella salina culture. The effect on growth and pigment content was recorded for various frequencies of the light pattern, by setting different paddle wheel velocities. Results show that the frequency of this realistic signal plays a decisive role in the dynamics of photosynthesis, thus revealing an unexpected photosynthetic response compared to that recorded under the on/off signals usually used in the literature. Indeed, the light received by a single cell contains signals from low to high frequencies that nonlinearly interact with the photosynthesis process and differentially stimulate the various time scales associated with photoacclimation and energy dissipation. This study highlights the need for experiments with more realistic light stimuli to better understand microalgal growth at high cell densities. An experimental protocol is also proposed, with simple, yet more realistic, step functions for light fluctuations.

Published
2018
Full Text
View/download PDF

28. Les jurys de thèse ont-ils un sexe ? Enquête sur le dispositif « Refusons le 0 % » à l’Université Toulouse III

Author

Chloé Delacroix, Catherine Armengaud, and Jean-Yves Le Talec

Subjects
genre, université, jurys de thèse, égalité femmes-hommes
Abstract

Cette recherche porte sur la composition sexuée des jurys de thèse. En 2016, l’université Toulouse III-Paul Sabatier a mis en place le dispositif « Refusons le 0 % », afin que tous les jurys de thèse locaux soient mixtes (c’est-à-dire qu’ils soient composés d’au moins une personne de chaque sexe). Cette recherche analyse l’effet de cette mesure, en comparant la composition sexuée des jurys de thèse en 2015 et 2016, tout en recueillant les représentations exprimées par une partie des universitaires concerné·e·s. Les résultats de cette enquête ont permis de quantifier les inégalités sexuées dans les jurys de thèse et d’analyser les effets des rapports sociaux de sexe à l’œuvre dans ces jurys. Ils montrent que le dispositif « Refusons le 0 % » s’avère efficace lorsque qu’il est assorti de sanctions en cas de non respect, mais ils indiquent également que s’instaure une forme de « résistance masculine au changement », dans la mesure où l’effectif des jurys tend à augmenter et, qu’en conséquence, le nombre d’hommes ne diminue pas. Les commentaires recueillis auprès des enseignant·e·s-chercheur·e·s soulignent enfin que le sujet de l’égalité femmes-hommes à l’université demeure polémique.

Published
2022

29. Dynamical Darwinian selection of a more productive strain of Tisochrysis lutea

Author

H. Bonnefond, Y. Lie, T. Lacour, B. Saint-Jean, G. Carrier, E. Pruvost, A. Talec, O. Bernard, A. Sciandra, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Biological control of artificial ecosystems (BIOCORE), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'océanographie de Villefranche (LOV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and ANR-12-BIME-0004,Facteur 4,AMELIORATION NON OGM DES PERFORMANCES DE MICROALGUES(2012)

Subjects
Pigments, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, Biomass productivity, ALE, Microalgae, Adaptation, Adaptive laboratory evolution, Agronomy and Crop Science, Selection, ComputingMilieux_MISCELLANEOUS
Abstract

Species domestication and improvement were decisive in increasing agricultural production yields. The microalgae industry must now realize the same accomplishment to boost its development instead of only using wild strains. Although genetically engineering microalgae is a promising path to explore, the artificial modification of the microalgae genome can have adverse side-effects on biomass productivity. Here, we propose a Darwinian method to select and improve microalgal strains, exploiting the competitive exclusion principle in a dynamical environment to drive evolution. Choosing an appropriate selection pressure allows a new adapted population having enhanced properties to emerge. In a natural growing environment, light intensity is consistently changing due to meteorological events, differing microalgae concentration and other exogenous factors. Consequently, the pigmentary profile regulation and the associated genetic mechanism is highly modulable in most microalgae. On top of this, high light intensities are known to elicit strong cellular stresses. For these reasons, a dynamical light regime with high light intensities was deemed a potentially efficient selection factor for the emergence of a new strain adapted to higher irradiance levels. Following 160 days of selection under variable light intensity the biomass productivity of Tisochrysis lutea increased by 77%. Genetic analyses further confirmed the selection protocol's success, with the apparition of 2716 new alleles. To our knowledge, this is the first selection approach allowing a significant biomass productivity increase resulting from an enhanced capacity of microalgae pigment photoadaptation.

Published
2022
Full Text
View/download PDF

31. Continuous selection pressure to improve temperature acclimation of Tisochrysis lutea.

Author

Hubert Bonnefond, Ghjuvan Grimaud, Judith Rumin, Gaël Bougaran, Amélie Talec, Manon Gachelin, Marc Boutoute, Eric Pruvost, Olivier Bernard, and Antoine Sciandra

Subjects
Medicine, Science
Abstract

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 temperature was kept constant along the experiment. This protocol resulted in a thermal niche increase by 3°C (+16.5%), with an enhancement by 9% of the maximal growth rate. The selection process also affected T. lutea physiology, with a feature generally observed for 'cold-temperature' type of adaptation. The amount of total and neutral lipids was significantly increased, and eventually productivity was increased by 34%. This seven month selection experiment, carried out in a highly dynamic environment, challenges some of the hypotheses classically advanced to explain the temperature response of microalgae.

Published
2017
Full Text
View/download PDF

32. Relying on pulse oximetry to avoid hypoxaemia and hyperoxia: A multicentre prospective cohort study in patients with circulatory failure

Author

Boulain, Thierry, primary, Nay, Mai-Anh, additional, Dequin, Pierre-François, additional, Lascarrou, Jean-Baptiste, additional, Vignon, Philippe, additional, Kamel, Toufik, additional, Muller, Grégoire, additional, Ehrmann, Stephan, additional, Baudin, Olivier, additional, Calvat, Sylvie, additional, Cracco, Christophe, additional, Desachy, Arnault, additional, Lafon, Charles, additional, Boitrou, Emmanuelle, additional, Follin, Arnaud, additional, Mentec, Hervé, additional, Pajot, Olivier, additional, Plantefève, Gaëtan, additional, Thirion, Marina, additional, Bruyère, Rémi, additional, Quenot, Jean-Pierre, additional, Bachoumas, Konstantinos, additional, Fiancette, Maud, additional, Lacherade, Jean Claude, additional, Lebert, Christine, additional, Martin-Lefèvre, Laurent, additional, Reignier, Jean, additional, Vinatier, Isabelle, additional, Yehia, Aihem, additional, Begot, Emmanuelle, additional, Bellier, Remy, additional, Clavel, Marc, additional, François, Bruno, additional, Galy, Antoine, additional, Pichon, Nicolas, additional, Bardou, Patrick, additional, Bellec, Frédéric, additional, Bonnivard, Michel, additional, Marco, Anne, additional, Roustan, Jérôme, additional, Vimeux, Sylvie, additional, Bretagnol, Anne, additional, Mathonnet, Armelle, additional, Bercault, Nicolas, additional, Réminiac, François, additional, Runge, Isabelle, additional, Skarzynski, Marie, additional, Chatellier, Delphine, additional, Coudroy, Rémi, additional, Frat, Jean-Pierre, additional, Goudet, Véronique, additional, Robert, René, additional, Veinstein, Anne, additional, Botoc, Vlad, additional, Chevalier, Stéphanie, additional, Collet, François, additional, Gouello, Jean-Paul, additional, Badin, Julie, additional, Guillon, Antoine, additional, Legras, Annick, additional, Masseret, Elodie, additional, Mercier, Emmanuelle, additional, and Talec, Patrice, additional

Published
2022
Full Text
View/download PDF

33. Des Men’s Studies aux Masculinity Studies : du patriarcat à la pluralité des masculinités

Author

Jean-Yves Le Talec

Subjects
feminism, men, masculinity, male, gender relations, Sociology (General), HM401-1281
Abstract

Because the androcentric bias of social sciences, which they pointed out in the early seventies, the academic feminists strongly suggested to study men as a gender category, and not as the standard case in social research. Therefore, according to the materialistic theory, men’s practices should always be analysed within the framework of hierarchical gender relations and the context of the patriarcal system. Later on, Raewyn Connell and other english-speaking scholars put forward the concept of masculinity in order to comprehend the pattern of power between different groups of men, with reference to gender relations as well, and to the configuration of hegemonic masculinity which is supposed to ensure male domination over women. Depite some differences, both approaches have many in common, and help to understand either remarkable or common maculinities in the current globalised social world, either opposed or in favour of feminism and social change.

Published
2016

34. Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta)

Author

A. Talec, A. Sciandra, M. L. Pedrotti, O. Bernard, L. Beaufort, and M. N. Müller

Subjects
Ecology, QH540-549.5, Life, QH501-531, Geology, QE1-996.5
Abstract

Coccolithophores, a key phytoplankton group, are one of the most studied organisms regarding their physiological response to ocean acidification/carbonation. The biogenic production of calcareous coccoliths has made coccolithophores a promising group for paleoceanographic research aiming to reconstruct past environmental conditions. Recently, geochemical and morphological analyses of fossil coccoliths have gained increased interest in regard to changes in seawater carbonate chemistry. The cosmopolitan coccolithophore Emiliania huxleyi (Lohm.) Hay and Mohler was cultured over a range of pCO2 levels in controlled laboratory experiments under nutrient replete and nitrogen limited conditions. Measurements of photosynthesis and calcification revealed, as previously published, an increase in particulate organic carbon production and a moderate decrease in calcification from ambient to elevated pCO2. The enhancement in particulate organic carbon production was accompanied by an increase in cell diameter. Changes in coccolith volume were best correlated with the coccosphere/cell diameter and no significant correlation was found between the coccolith volume and the particulate inorganic carbon production. The conducted experiments revealed that the coccolith volume of E. huxleyi is variable with aquatic CO2 concentration but its sensitivity is rather small in comparison with its sensitivity to nitrogen limitation. Comparing coccolith morphological and geometrical parameters like volume, mass and size to physiological parameters under controlled laboratory conditions is an important step to understand variations in fossil coccolith geometry.

Published
2012
Full Text
View/download PDF

37. Relying on pulse oximetry to avoid hypoxaemia and hyperoxia: A multicentre prospective cohort study in patients with circulatory failure

Author

Thierry Boulain, Mai-Anh Nay, Pierre-François Dequin, Jean-Baptiste Lascarrou, Philippe Vignon, Toufik Kamel, Grégoire Muller, Stephan Ehrmann, Olivier Baudin, Sylvie Calvat, Christophe Cracco, Arnault Desachy, Charles Lafon, Emmanuelle Boitrou, Arnaud Follin, Hervé Mentec, Olivier Pajot, Gaëtan Plantefève, Marina Thirion, Rémi Bruyère, Jean-Pierre Quenot, Konstantinos Bachoumas, Maud Fiancette, Jean Claude Lacherade, Christine Lebert, Laurent Martin-Lefèvre, Jean Reignier, Isabelle Vinatier, Aihem Yehia, Emmanuelle Begot, Remy Bellier, Marc Clavel, Bruno François, Antoine Galy, Nicolas Pichon, Patrick Bardou, Frédéric Bellec, Michel Bonnivard, Anne Marco, Jérôme Roustan, Sylvie Vimeux, Anne Bretagnol, Armelle Mathonnet, Nicolas Bercault, François Réminiac, Isabelle Runge, Marie Skarzynski, Delphine Chatellier, Rémi Coudroy, Jean-Pierre Frat, Véronique Goudet, René Robert, Anne Veinstein, Vlad Botoc, Stéphanie Chevalier, François Collet, Jean-Paul Gouello, Julie Badin, Antoine Guillon, Annick Legras, Elodie Masseret, Emmanuelle Mercier, and Patrice Talec

Subjects
Emergency Nursing, Critical Care Nursing
Abstract

The purpose of this study was to assess the predictive performance of pulse oximetry (SpOSpOFive hundred seventy-one patients (mean [standard deviation] Simplified Acute Physiology Score II: 58.7 [20.1]; mechanically ventilated 75.6%) with 2643 available SaO

Published
2022

38. La Liste rouge des espèces menacées en France - Poissons récifaux de La Réunion

Author

Moncorps, Sébastien, Poncet, Laurent, Touroult, Julien, Gigot, Guillaume, Kirchner, Florian, Dumestre, Marielle, Soubeyran, Yohann, Wickel, Julien, Chabanet, Pascale, Durville, Patrick, Roos, David, Rungassamy, Tevamie, Rodicq, Juliette, Fricke, Ronald, Talec, Pascal, Union Internationale pour la Conservation de la Nature (UICN), Patrimoine naturel (PatriNat), Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Office français de la biodiversité (OFB), Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Staatliches Museum für Naturkunde Stuttgart (SMNS), Ministère de l'environnement, Ministère de l'Environnement, and Comité français de l'UICN, OFB & MNHN

Subjects
[SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Published
2022

39. Adaptative laboratory evolution for enhanced EPS production in biofilm forming microalgae

Author

Pham, Aurélie, Sciandra, Antoine, Bernard, Olivier, Guihéneuf, Freddy, Bonnefond, Hubert, Talec, Amélie, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biological control of artificial ecosystems (BIOCORE), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'océanographie de Villefranche (LOV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Inalve, and Sciandra, Antoine

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, ComputingMilieux_MISCELLANEOUS, [SDV.BIO] Life Sciences [q-bio]/Biotechnology
Abstract

International audience

Published
2021

41. Independence of a Marine Unicellular Diazotroph to the Presence of NO3−

Author

Amélie Talec, Sophie Rabouille, Amel Latifi, Andreas Oschlies, Thierry Blasco, Benjamin Randall, Patrick Raimbault, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB)

Subjects
0106 biological sciences, Microbiology (medical), inorganic chemicals, Biogeochemical cycle, QH301-705.5, 01 natural sciences, Microbiology, Article, 03 medical and health sciences, chemistry.chemical_compound, Nitrate, Virology, Botany, Crocosphaera, 14. Life underwater, Biology (General), nitrate uptake, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 030304 developmental biology, 0303 health sciences, biology, Chemistry, 010604 marine biology & hydrobiology, organic chemicals, Carbon fixation, Nitrogenase, marine cyanobacteria, food and beverages, Crocosphaera watsonii, biology.organism_classification, Trichodesmium, nitrogen fixation, [SDE]Environmental Sciences, Nitrogen fixation, Diazotroph
Abstract

Marine nitrogen (N2) fixation was historically considered to be absent or reduced in nitrate (NO3−) rich environments. This is commonly attributed to the lower energetic cost of NO3− uptake compared to diazotrophy in oxic environments. This paradigm often contributes to making inferences about diazotroph distribution and activity in the ocean, and is also often used in biogeochemical ocean models. To assess the general validity of this paradigm beyond the traditionally used model organism Trichodesmium spp., we grew cultures of the unicellular cyanobacterium Crocosphaera watsonii WH8501 long term in medium containing replete concentrations of NO3−. NO3− uptake was measured in comparison to N2 fixation to assess the cultures’ nitrogen source preferences. We further measured culture growth rate, cell stoichiometry, and carbon fixation rate to determine if the presence of NO3− had any effect on cell metabolism. We found that uptake of NO3− by this strain of Crocosphaera was minimal in comparison to other N sources (~2–4% of total uptake). Furthermore, availability of NO3− did not statistically alter N2 fixation rate nor any aspect of cell physiology or metabolism measured (cellular growth rate, cell stoichiometry, cell size, nitrogen fixation rate, nitrogenase activity) in comparison to a NO3− free control culture. These results demonstrate the capability of a marine diazotroph to fix nitrogen and grow independently of NO3−. This lack of sensitivity of diazotrophy to NO3− suggests that assumptions often made about, and model formulations of, N2 fixation should be reconsidered.

Published
2021
Full Text
View/download PDF

42. Les Ours et la Lady

Author

Jean-Yves Le Talec

Subjects
Effeminacy, media_common.quotation_subject, Masculinity, Ethnography, Coming out, General Social Sciences, Art, Humanities, Male Homosexuality, Hegemonic masculinity, media_common, Virility
Abstract

EnglishThe bear phenomenon, which goes back to the coming up of the modern American gay culture during the sixties and the seventies, has been expanding in Europe since the turn of the 21st century, appealing mostly mature, white, middle-class, urban men. This ethnographic study aims to describe an annual bear meeting, The Bears Week, organized in Sitges (Spain) and mainly attended by gay men living in Europe. It attempts as well to highlight the gender dynamics at work during this festive and sexual gathering. Along the week, thousands of men spread across the city, and crowd in several hot spots: some specific beaches during the day, and the gay area of Sitges at night, where they have been observed. As diverse and inclusive as it can be, and whatever it may precisely mean on an individual basis, the “bear identity” proceeds from a performance of hegemonic masculinity combined with an exhibition of male homosexuality. It involves manifesting virility and cool maleness, coming out as a gay regular guy, and touching bodies around in order to express camaraderie and togetherness. Beyond that, many bears also happen to perform effeminacy, or at least to demonstrate a kind of familiarity and complicity with genderfuck and camp culture. The Bears Week do not strictly stand for a community meeting, nor for an identity event, but produces during a week an ongoing party, a sexual gathering, and sets a gender scene for gay masculinity. francaisLe phenomene bear s’est developpe aux Etats-Unis, avec l’emergence de la culture gaie contemporaine au cours des annees 1960 et 1970. Il s’est repandu en Europe au debut des annees 2000, en attirant surtout des hommes murs, blancs, de classe moyenne et urbains. Cette recherche ethnographique vise a decrire la Bears Week, un rassemblement annuel organise a Sitges (Espagne) et frequente principalement par des hommes gais europeens. Elle s’attache egalement a analyser la dynamique du genre a l’œuvre pendant ce regroupement festif et sexuel. Pendant une semaine, des milliers d’hommes convergent en ville et se concentrent particulierement dans des lieux specifiques : quelques plages durant le jour, le quartier gai de Sitges durant la nuit, ou ils ont ete observes. Aussi diverse et inclusive qu’elle puisse etre, et quel que soit le sens precis que lui donne chaque individu, « l’identite bear » procede a la fois d’une performance de la masculinite hegemonique et d’une sexualite rendue visible, qui se traduisent par une presentation de soi masculine et une attitude virile, la mise en evidence d’une homosexualite « ordinaire » et la manifestation publique d’une camaraderie et d’une proximite avec ses pairs par le contact physique. En outre, ces hommes peuvent aussi performer l’effeminement, ou du moins manifester une forme de proximite et de complicite avec le « melange des genres » et la culture camp. Sans etre vraiment un rassemblement communautaire ni une mobilisation identitaire, la Bears Week se presente comme une semaine de fete, de rencontres sexuelles, et pose le decor d’un theâtre du genre et de la masculinite gaie.

Published
2019
Full Text
View/download PDF

46. Enhancing PUFA-rich polar lipids in Tisochrysis lutea using adaptive laboratory evolution (ALE) with oscillating thermal stress

Author

Olivier Bernard, Manon Gachelin, Gregory Carrier, Freddy Guihéneuf, M. Boutoute, Antoine Sciandra, Eric Pruvost, Amélie Talec, Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Atlantique (IFREMER Atlantique), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Inalve, Biological control of artificial ecosystems (BIOCORE), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'océanographie de Villefranche (LOV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, Microorganism, Population, Applied Microbiology and Biotechnology, 03 medical and health sciences, Microalgae, Membrane fluidity, medicine, Tisochrysis lutea, Adaptive laboratory evolution (ALE), Growth rate, Food science, education, 030304 developmental biology, chemistry.chemical_classification, 0303 health sciences, education.field_of_study, medicine.diagnostic_test, 030306 microbiology, Fatty Acids, Temperature, Haptophyta, food and beverages, Fatty acid, General Medicine, Lipids, Polar lipids, DHA, chemistry, Fatty Acids, Unsaturated, lipids (amino acids, peptides, and proteins), Laboratories, Lipid profile, Biotechnology, Polyunsaturated fatty acid
Abstract

Adaptive laboratory evolution is a powerful tool for microorganism improvement likely to produce enhanced microalgae better tailored to their industrial uses. In this work, 12 wild-type strains of Tisochrysis lutea were co-cultivated under increasing thermal stress for 6 months. Indeed, temperature was oscillating daily between a high and a low temperature, with increasing amplitude along the experiment. The goal was to enhance the polyunsaturated fatty acid content of the polar lipids. Samples were taken throughout the evolution experiment and cultivated in standardized conditions to analyze the evolution of the lipid profile. Genomic analysis of the final population shows that two strains survived. The lipid content doubled, impacting all lipid classes. The fatty acid analyses show a decrease in SFAs correlated with an increase in monounsaturated fatty acids (MUFAs), while changes in polyunsaturated fatty acid (PUFAs) vary between both photobioreactors. Hence, the proportion of C18-MUFAs (18:1 n-9) and most C18-PUFAs (18:2 n-6, 18:3 n-3, and 18:4 n-3) increased, suggesting their potential role in adjusting membrane fluidity to temperature shifts. Of particular interest, DHA in polar lipids tripled in the final population while the growth rate was not affected. KEY POINTS: • Adaptive laboratory evolution on a mix of 12 T. lutea strains led to survival of 2 • Thermal stress impacted cell size, total lipid cell content, and all lipid classes • DHA cell content partitioned to polar lipids tripled throughout the experiment.

Published
2021
Full Text
View/download PDF

47. Independence of a Marine Unicellular Diazotroph to the Presence of NO3−

Author

Rabouille, Sophie, Randall, Benjamin, Talec, Amélie, Raimbault, Patrick, Blasco, Thierry, Latifi, Amel, Oschlies, Andreas, Rabouille, Sophie, Randall, Benjamin, Talec, Amélie, Raimbault, Patrick, Blasco, Thierry, Latifi, Amel, and Oschlies, Andreas

Abstract

Marine nitrogen (N2 ) fixation was historically considered to be absent or reduced in nitrate (NO3− ) rich environments. This is commonly attributed to the lower energetic cost of NO3− uptake compared to diazotrophy in oxic environments. This paradigm often contributes to making inferences about diazotroph distribution and activity in the ocean, and is also often used in biogeochemical ocean models. To assess the general validity of this paradigm beyond the traditionally used model organism Trichodesmium spp., we grew cultures of the unicellular cyanobacterium Crocosphaera watsonii WH8501 long term in medium containing replete concentrations of NO3− . NO3− uptake was measured in comparison to N2 fixation to assess the cultures’ nitrogen source preferences. We further measured culture growth rate, cell stoichiometry, and carbon fixation rate to determine if the presence of NO3 − had any effect on cell metabolism. We found that uptake of NO3− by this strain of Crocosphaera was minimal in comparison to other N sources (~2–4% of total uptake). Furthermore, availability of NO3 − did not statistically alter N2 fixation rate nor any aspect of cell physiology or metabolism measured (cellular growth rate, cell stoichiometry, cell size, nitrogen fixation rate, nitrogenase activity) in comparison to a NO3− free control culture. These results demonstrate the capability of a marine diazotroph to fix nitrogen and grow independently of NO3− . This lack of sensitivity of diazotrophy to NO3− suggests that assumptions often made about, and model formulations of, N2 fixation should be reconsidered.

Published
2021
Full Text
View/download PDF

48. Amours Transi(t)s

Author

Jean-Yves Le Talec and Laurent Gaissad

Subjects
Sociology (General), HM401-1281
Published
2012

Catalog

Books, media, physical & digital resources
See catalog results