22 results on '"Villanova, Valeria"'
Search Results
2. Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Fortunato, Antonio Emidio, Singh, Dipali, Dal Bo, Davide, Conte, Melissa, Obata, Toshihiro, Jouhet, Juliette, Fernie, Alisdair R., Marechal, Eric, Falciatore, Angela, Pagliardini, Julien, Le Monnier, Adeline, Poolman, Mark, Curien, Gilles, Petroutsos, Dimitris, and Finazzi, Giovanni
- Published
- 2017
3. A systems-wide understanding of photosynthetic acclimation in algae and higher plants
- Author
-
Moejes, Fiona Wanjiku, Matuszyńska, Anna, Adhikari, Kailash, Bassi, Roberto, Cariti, Federica, Cogne, Guillaume, Dikaios, Ioannis, Falciatore, Angela, Finazzi, Giovanni, Flori, Serena, Goldschmidt-Clermont, Michel, Magni, Stefano, Maguire, Julie, Le Monnier, Adeline, Müller, Kathrin, Poolman, Mark, Singh, Dipali, Spelberg, Stephanie, Stella, Giulio Rocco, Succurro, Antonella, Taddei, Lucilla, Urbain, Brieuc, Villanova, Valeria, Zabke, Claudia, and Ebenhöh, Oliver
- Published
- 2017
4. Two-phase microalgae cultivation for RAS water remediation and high-value biomass production
- Author
-
Villanova, Valeria, primary, Roques, Jonathan Armand Charles, additional, Forghani, Bita, additional, Shaikh, Kashif Mohd, additional, Undeland, Ingrid, additional, and Spetea, Cornelia, additional
- Published
- 2023
- Full Text
- View/download PDF
5. Mixotrophy in a Local Strain of Nannochloropsis granulata for Renewable High-Value Biomass Production on the West Coast of Sweden
- Author
-
Villanova, Valeria, primary, Galasso, Christian, additional, Vitale, Giovanni Andrea, additional, Della Sala, Gerardo, additional, Engelbrektsson, Johan, additional, Strömberg, Niklas, additional, Shaikh, Kashif Mohd, additional, Andersson, Mats X., additional, Palma Esposito, Fortunato, additional, Ekendahl, Susanne, additional, De Pascale, Donatella, additional, and Spetea, Cornelia, additional
- Published
- 2022
- Full Text
- View/download PDF
6. Energetic coupling between plastids and mitochondria drives C[O.sub.2] assimilation in diatoms
- Author
-
Bailleul, Benjamin, Berne, Nicolas, Murik, Omer, Petroutsos, Dimitris, Prihoda, Judit, Tanaka, Atsuko, Villanova, Valeria, Bligny, Richard, Flori, Serena, Falconet, Denis, Krieger-Liszkay, Anja, Santabarbara, Stefano, Rappaport, Fabrice, Joliot, Pierre, Tirichine, Leila, Falkowski, Paul G., Cardol, Pierre, Bowler, Chris, and Finazzi, Giovanni
- Subjects
Diatoms -- Research ,Mitochondria -- Physiological aspects ,Photosynthesis -- Research ,Phytochemistry -- Research ,Botanical research ,Plastids -- Physiological aspects ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate [...]
- Published
- 2015
7. Boosting Biomass Quantity and Quality by Improved Mixotrophic Culture of the Diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, primary, Singh, Dipali, additional, Pagliardini, Julien, additional, Fell, David, additional, Le Monnier, Adeline, additional, Finazzi, Giovanni, additional, and Poolman, Mark, additional
- Published
- 2021
- Full Text
- View/download PDF
8. Combined effect of nutrient and flashing light frequency for a biochemical composition shift in Nannochloropsis gaditana grown in a quasi‐isoactinic reactor
- Author
-
Lima, Serena, primary, Villanova, Valeria, additional, Grisafi, Franco, additional, Brucato, Alberto, additional, and Scargiali, Francesca, additional
- Published
- 2020
- Full Text
- View/download PDF
9. Supplementary Fig. 1 Quantitative analysis of P. tricornutum glycerolipids from Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Fortunato, Antonio Emidio, Dipali Singh, Bo, Davide Dal, Conte, Melissa, Obata, Toshihiro, Jouhet, Juliette, Fernie, Alisdair R., Marechal, Eric, Falciatore, Angela, Pagliardini, Julien, Monnier, Adeline Le, Poolman, Mark, Curien, Gilles, Petroutsos, Dimitris, and Finazzi, Giovanni
- Abstract
TAG profile in a total lipid extract from cells grown in replete conditions (A) and deplete conditions (B) in both mixotrophic and phototrophic mode. Glycerolipids are expressed in nmol / mg of dry cells. Each result is the average of two biological replicates ± SD. PHOT: light in N-replete condition; PHOTO-N: light in N-deplete condi-tion; MIX: light+glycerol in N-replete condition; MIX-N: light+glycerol in N-deplete condition.
- Published
- 2017
- Full Text
- View/download PDF
10. Supplementary Fig. 3 Quantification of intracellular pyruvate by a fluorescence-based method from Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Fortunato, Antonio Emidio, Dipali Singh, Bo, Davide Dal, Conte, Melissa, Obata, Toshihiro, Jouhet, Juliette, Fernie, Alisdair R., Marechal, Eric, Falciatore, Angela, Pagliardini, Julien, Monnier, Adeline Le, Poolman, Mark, Curien, Gilles, Petroutsos, Dimitris, and Finazzi, Giovanni
- Abstract
A. Pyruvate standard curve. B. Quantification of intracellular pyruvate in cells grown in phototrophy (PHOT) and mixotrophy (MIX).
- Published
- 2017
- Full Text
- View/download PDF
11. Supplementary Fig. 2 Membrane lipid composition in P. tricornutum from Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Fortunato, Antonio Emidio, Dipali Singh, Bo, Davide Dal, Conte, Melissa, Obata, Toshihiro, Jouhet, Juliette, Fernie, Alisdair R., Marechal, Eric, Falciatore, Angela, Pagliardini, Julien, Monnier, Adeline Le, Poolman, Mark, Curien, Gilles, Petroutsos, Dimitris, and Finazzi, Giovanni
- Abstract
Lipid analysis of cells grow in N-replete conditions and N-deplete conditions in both mixotrophic and phototrophic mode. Each result is the average of two biological replicates ± SD. SQDG, sulfoquinovosyldiacylglycerol; DGDG, digalactosyldiacylglycerol; MGDG, monogalactosyldiacylglycerol; PC, phosphatidylcholine; PHOT: light in N-replete condition; PHOTO-N: light in N-deplete condition; MIX: light+glycerol in N-replete condition; MIX-N: light+glycerol in N-deplete condition.
- Published
- 2017
- Full Text
- View/download PDF
12. Supplementary Fig. 4 A Respiration and photosynthesis in P. tricornutum cells from Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Fortunato, Antonio Emidio, Dipali Singh, Bo, Davide Dal, Conte, Melissa, Obata, Toshihiro, Jouhet, Juliette, Fernie, Alisdair R., Marechal, Eric, Falciatore, Angela, Pagliardini, Julien, Monnier, Adeline Le, Poolman, Mark, Curien, Gilles, Petroutsos, Dimitris, and Finazzi, Giovanni
- Abstract
Direct assessment of oxygen consumption by a polarographic approach in both phototrophy (black bar) and mix-otrophy (red bar). B. Fluorescent based-assay to monitoring the changes in respiration using the Redox Dye A in presence of the selected compounds (see methods).
- Published
- 2017
- Full Text
- View/download PDF
13. Supplementary Fig. 5 Screening of mixotrophic efficiency by biolog and redox dye assay in P. tricornutum from Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Fortunato, Antonio Emidio, Dipali Singh, Bo, Davide Dal, Conte, Melissa, Obata, Toshihiro, Jouhet, Juliette, Fernie, Alisdair R., Marechal, Eric, Falciatore, Angela, Pagliardini, Julien, Monnier, Adeline Le, Poolman, Mark, Curien, Gilles, Petroutsos, Dimitris, and Finazzi, Giovanni
- Abstract
A. OD750 nm changes (relative to phototrophic growth) of P. tricornutum cells grown for 6 days in BiologTM plates P1 and PM2A that contains 190 carbon compounds (see methods). Each data point represents a different com-pound. B. Growth profile of P. tricornutum on few selected compounds (at 20 mM) and a phototrophic control in 100 mL flasks. C. Areas under the growth curves of Supplementary Fig. 5B normalized to the area of the curve of phototrophic growth.
- Published
- 2017
- Full Text
- View/download PDF
14. A systems-wide understanding of photosynthetic acclimation in algae and higher plants
- Author
-
Wanjiku Moejes, Fiona, Matuszyńska, Anna, Adhikari, Kailash, Bassi, Roberto, Cariti, Federica, Cogne, Guillaume, Dikaios, Joannis, Falciatore, Angela, Finazzi, Giovanni, Flori, Serena, Goldschmidt-Clermont, Michel, Magni, Stefano, Maguire, Julie, Le Monnier, Adeline, Müller, Kathrin, Poolman, Mark, Singh, Dipali, Spelberg, Stephanie, Stella, Giulio Rocco, Succurro, Antonella, Taddei, Lucilla, Urbain, Brieuc, Villanova, Valeria, Zabke, Claudia, Ebenhöh, Oliver, Wanjiku Moejes, Fiona, Matuszyńska, Anna, Adhikari, Kailash, Bassi, Roberto, Cariti, Federica, Cogne, Guillaume, Dikaios, Joannis, Falciatore, Angela, Finazzi, Giovanni, Flori, Serena, Goldschmidt-Clermont, Michel, Magni, Stefano, Maguire, Julie, Le Monnier, Adeline, Müller, Kathrin, Poolman, Mark, Singh, Dipali, Spelberg, Stephanie, Stella, Giulio Rocco, Succurro, Antonella, Taddei, Lucilla, Urbain, Brieuc, Villanova, Valeria, Zabke, Claudia, and Ebenhöh, Oliver
- Abstract
The ability of phototrophs to colonise different environments relies on robust protection against oxidative stress, a critical requirement for the successful evolutionary transition from water to land. Photosynthetic organisms have developed numerous strategies to adapt their photosynthetic apparatus to changing light conditions in order to optimise their photosynthetic yield, which is crucial for life on Earth to exist. Photosynthetic acclimation is an excellent example of the complexity of biological systems, where highly diverse processes, ranging from electron excitation over protein protonation to enzymatic processes coupling ion gradients with biosynthetic activity, interact on drastically different timescales from picoseconds to hours. Efficient functioning of the photosynthetic apparatus and its protection is paramount for efficient downstream processes, including metabolism and growth. Modern experimental techniques can be successfully integrated with theoretical and mathematical models to promote our understanding of underlying mechanisms and principles. This review aims to provide a retrospective analysis of multidisciplinary photosynthetic acclimation research carried out by members of the Marie Curie Initial Training Project, AccliPhot, placing the results in a wider context. The review also highlights the applicability of photosynthetic organisms for industry, particularly with regards to the cultivation of microalgae. It intends to demonstrate how theoretical concepts can successfully complement experimental studies broadening our knowledge of common principles in acclimation processes in photosynthetic organisms, as well as in the field of applied microalgal biotechnology.
- Published
- 2017
- Full Text
- View/download PDF
15. A systems-wide understanding of photosynthetic acclimation in algae and higher plants
- Author
-
Matuszy?ska, Anna, Moejes, Fiona Wanjiku, Adhikari, Kailash, Bassi, Roberto, Cariti, Federica, Cogne, Guillaume, Dikaios, Ioannis, Falciatore, Angela, Finazzi, Giovanni, Flori, Serena, Goldschmidt-Clermont, Michel, Magni, Stefano, Maguire, Julie, Le Monnier, Adeline, Müller, Kathrin, Poolman, Mark, Singh, Dipali, Spelberg, Stephanie, Stella, Giulio Rocco, Succurro, Antonello, Taddei, Lucilla, Urbain, Brieuc, Villanova, Valeria, Zabke, Claudia, Ebenhöh, Oliver, Matuszy?ska, Anna, Moejes, Fiona Wanjiku, Adhikari, Kailash, Bassi, Roberto, Cariti, Federica, Cogne, Guillaume, Dikaios, Ioannis, Falciatore, Angela, Finazzi, Giovanni, Flori, Serena, Goldschmidt-Clermont, Michel, Magni, Stefano, Maguire, Julie, Le Monnier, Adeline, Müller, Kathrin, Poolman, Mark, Singh, Dipali, Spelberg, Stephanie, Stella, Giulio Rocco, Succurro, Antonello, Taddei, Lucilla, Urbain, Brieuc, Villanova, Valeria, Zabke, Claudia, and Ebenhöh, Oliver
- Abstract
The ability of phototrophs to colonise different environments relied on the robust protection against oxidative stress in phototrophs, a critical requirement for the successful evolutionary transition from water to land. Photosynthetic organisms have developed numerous strategies to adapt their photosynthetic apparatus to changing light conditions in order to optimise their photosynthetic yield, crucial for life to exist on Earth. Photosynthetic acclimation is an excellent example of the complexity of biological systems, in which highly diverse processes, ranging from electron excitation over protein protonation to enzymatic processes coupling ion gradients with biosynthetic activity interact on drastically different timescales, ranging from picoseconds to hours. An efficient functioning of the photosynthetic apparatus and its protection is paramount for efficient downstream processes including metabolism and growth. Modern experimental techniques can be successfully integrated with theoretical and mathematical models to promote our understanding of underlying mechanisms and principles. This Review aims to provide a retrospective analysis of multidisciplinary photosynthetic acclimation research carried out by members of the Marie Curie Initial Training Project “AccliPhot”, placing the results in a wider context. The Review also highlights the applicability of photosynthetic organisms for industry, particularly with regards to the cultivation of microalgae. It aims to demonstrate how theoretical concepts can successfully complement experimental studies broadening our knowledge of common principles in acclimation processes in photosynthetic organisms, as well as in the field of applied microalgal biotechnology.
- Published
- 2017
16. Identification du mécanisme de la mixotrophie chez Phaeodactylum tricornutum
- Author
-
Villanova, Valeria, Physiologie cellulaire et végétale (LPCV), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes, Giovanni Finazzi, Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), STAR, ABES, and Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG)
- Subjects
Glycerol ,Diatoms ,Diatomées ,Mixotrophie ,Photobioreactor ,[SDV.BC]Life Sciences [q-bio]/Cellular Biology ,[SDV.BC] Life Sciences [q-bio]/Cellular Biology ,Mixotrophy ,Photobioréacteur - Abstract
Diatoms are photosynthetic organisms with a strong influence on the global biogeochemistry. Moreover, they are extremely interesting as potential feedstocks for the production of high-value molecules and biofuel. They are endosymbiotic organisms originated by the fusion of a heterotrophic ancestor with one or more photosynthetic microalgae. This has led to an extremely flexible cell metabolism. Like other microalgae, diatoms are able to grow in the presence of both light and of a reduced carbon source. The simultaneous use of photosynthesis and respiration can increase biomass productivity and reduce the energy cost of the industrial exploitation of diatoms.In this project, the mechanism and the consequences of mixotrophic metabolism have been studied in the model diatom Phaeodactylum tricornutum. In the first part, I have studied the molecular mechanism governing the interactions between chloroplast and mitochondrion. We have demonstrated that the NADPH generated in the plastid is exported to the mitochondrion to generate additional ATP, which, once back to the plastid, is used for carbon fixation. Overall, this work shows that the interaction between these two organelles increases carbon fixation and growth in diatoms. We hence suggest that the simultaneous use of carbon and light energy sources (i.e. mixotrophy) should enhance biomass productivity in diatoms. This hypothesis has been tested in the second part of my thesis, where I focused on the consequences of mixotrophy on metabolism. By combining metabolomic, transcriptomic, lipidomic and physiology approaches, I have contributed to elucidate the main pathways targeted by mixotrophy (central carbon, lipid and storage carbon metabolism). In the last part of this work, I have worked on improving the culture conditions and medium composition to boost microalgal productivity by mixotrophy. These conditions have been scaled-up in lab scale photobioreactors, revealing the industrial exploitation potential of Phaeodactylum., Les diatomées jouent un rôle primordial dans l'écologie de la planète, car elles sont responsables du 20-40% de la productivite mondial d’oxygène. Elles figurent parmi les organismes à fort potentiel biotechnologique pour des applications biocarburant. Les diatomées sont des organismes symbiotiques issus de la fusion d'un ancêtre hétérotrophe avec une ou plusieurs micro-algues photosynthétiques. Grace à cette histoire évolutive complexe, les diatomées ont un métabolisme très flexible. Comme la plus part des microalgues elles peuvent utiliser la photosynthèse pour leur croissance, mais aussi la mixotrophie, i.e. la capacité de croître en présence de lumière et d’une source de carbone réduit. L'utilisation simultanée de la photosynthèse et de la respiration peut augmenter la productivité de la biomasse des microalgues et réduire ainsi le coût de leur exploitation industrielle. Dans cette thèse j’ai étudié le mécanisme et les conséquences du métabolisme mixotrophique chez la diatomée modèle Phaeodactylum tricornutum. J’ai contribué à étudier le mécanisme moléculaire à la base des interactions énérgétiques entre chloroplaste et mitochondrie. Dans ce travail, nous avons démontré que le NADPH généré dans le chloroplaste est exporté vers la mitochondrie pour générer de l’ATP requis pour la fixation du CO2 dans le chloroplaste. Cette interaction entre les deux organites cellulaires augmente la croissance de diatomées, et suggère que l'utilisation simultanée d’une source de carbone et de l'énergie lumineuse (mixotrophie) devrait augmenter la productivité de la biomasse chez les diatomées. Cette hypothèse a été testée dans la deuxième partie de ma thèse, où j’ai etudié les conséquences de la mixotrophie sur le métabolisme de Phaeodactylum. Grace à une approche métabolomique, transcriptomique, lipidomiques et de physiologie j’ai contribué à éclaircir les principales voies métaboliques (métabolisme centrale, métabolisme des lipides, métabolisme des polymères de réserve) concerné la mixotrophie. Dans la dernière partie de ce travail j’ai optimisé les conditions de culture et la composition du milieu afin d’améliorer la productivité en croissance mixotrophe chez Phaeodactylum. Ce résultat a été validé dans des photobioréacteurs à l'échelle labo pour tester le potentiel de l'exploitation industrielle de cet organisme.
- Published
- 2016
17. Pollutants Removal from Municipal Sewage by Means of Microalgae.
- Author
-
Lima, Serena, Villanova, Valeria, Richiusa, Monica, Grisafi, Franco, Scargiali, Francesca, and Brucato, Alberto
- Subjects
POLLUTANTS ,SEWAGE purification ,MICROALGAE ,CHEMICAL energy ,CHEMICAL oxygen demand - Abstract
Microalgae are microorganisms able to photosynthesize, namely transforming inorganic substrates and sun light into organic compounds and chemical energy. The industry of microalgae has expanded in the last decades and several applications are now developed, making their biomass interesting under an economic perspective. Nannochlopsis gaditana is one of the most interesting species already employed in industry because of its high content in lipids that could be employed as source for biodiesel synthesis but also in other fields such as cosmetic and pharmaceutic. One of the most promising application is the exploitation of microalgal grow for bioremediating wastewaters polluted with inorganic nutrients such as nitrates and phosphates that microalgae are able to employ as nutrients. Bio-treatment of wastewaters by using microalgae has the advantage to reclassify the water and preserve it from wasting while producing a valuable biomass. In this work, a microalgal strain, Nannochloropsis gaditana, was employed for testing its performance in the bioremediation of municipal sewages. The wastewater was taken from a municipal plant, after the primary treatment, and the algae processing was aimed at replacing the secondary treatment. Algal growth in its growth medium and in the sewage was compared and algal biomass was characterized. Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), total nitrogen and total phosphorous levels of the sewage before and after algae treatment were also determined in order to evaluate the efficiency of this microalgal strain on wastewater bioremediation. Our results showed that N. gaditana grows better in wastewater than in the control growth medium and it is able to efficiently remove nutrients from the sewage. However, COD and BOD values did not decrease after algal treatment. These results suggest that the use of selected bacteria and/or yeast strains (together with microalgae) could improve the efficiency of wastewater treatments decreasing BOD and COD values. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
18. The Water to Water Cycles in Microalgae
- Author
-
Curien, Gilles, primary, Flori, Serena, additional, Villanova, Valeria, additional, Magneschi, Leonardo, additional, Giustini, Cécile, additional, Forti, Giorgio, additional, Matringe, Michel, additional, Petroutsos, Dimitris, additional, Kuntz, Marcel, additional, and Finazzi, Giovanni, additional
- Published
- 2016
- Full Text
- View/download PDF
19. Membrane Glycerolipid Remodeling Triggered by Nitrogen and Phosphorus Starvation inPhaeodactylum tricornutum
- Author
-
Abida, Heni, primary, Dolch, Lina-Juana, additional, Meï, Coline, additional, Villanova, Valeria, additional, Conte, Melissa, additional, Block, Maryse A., additional, Finazzi, Giovanni, additional, Bastien, Olivier, additional, Tirichine, Leïla, additional, Bowler, Chris, additional, Rébeillé, Fabrice, additional, Petroutsos, Dimitris, additional, Jouhet, Juliette, additional, and Maréchal, Eric, additional
- Published
- 2014
- Full Text
- View/download PDF
20. Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms.
- Author
-
Bailleul, Benjamin, Berne, Nicolas, Murik, Omer, Petroutsos, Dimitris, Prihoda, Judit, Tanaka, Atsuko, Villanova, Valeria, Bligny, Richard, Flori, Serena, Falconet, Denis, Krieger-Liszkay, Anja, Santabarbara, Stefano, Rappaport, Fabrice, Joliot, Pierre, Tirichine, Leila, Falkowski, Paul G., Cardol, Pierre, Bowler, Chris, and Finazzi, Giovanni
- Subjects
PLASTIDS ,MITOCHONDRIA ,DIATOMS ,CARBON dioxide ,ABSORPTION ,LITHOSPHERE ,CARBON fixation ,ADENOSINE triphosphatase - Abstract
Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies principally on a range of plastid-localized ATP generating processes. Here we show that diatoms regulate ATP/NADPH through extensive energetic exchanges between plastids and mitochondria. This interaction comprises the re-routing of reducing power generated in the plastid towards mitochondria and the import of mitochondrial ATP into the plastid, and is mandatory for optimized carbon fixation and growth. We propose that the process may have contributed to the ecological success of diatoms in the ocean. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
21. Membrane Glycerolipid Remodeling Triggered by Nitrogen and Phosphorus Starvation in Phaeodactylum tricornutum.
- Author
-
Abida, Heni, Dolch, Lina-Juana, Meï, Coline, Villanova, Valeria, Conte, Melissa, Block, Maryse A., Finazzi, Giovanni, Bastien, Olivier, Tirichine, Leïla, Bowler, Chris, Rébeillé, Fabrice, Petroutsos, Dimitris, Jouhet, Juliette, and Maréchal, Eric
- Subjects
DIATOMS ,PHYTOPLANKTON ,NITROGEN ,PHOSPHORUS ,PHOSPHOLIPIDS - Abstract
Diatoms constitute a major phylum of phytoplankton biodiversity in ocean water and freshwater ecosystems. They are known to respond to some chemical variations of the environment by the accumulation of triacylglycerol, but the relative changes occurring in membrane glycerolipids have not yet been studied. Our goal was first to define a reference for the glycerolipidome of the marine model diatom Phaeodactylum tricornutum, a necessary prerequisite to characterize and dissect the lipid metabolic routes that are orchestrated and regulated to build up each subcellular membrane compartment. By combining multiple analytical techniques, we determined the glycerolipid profile of P. tricornutum grown with various levels of nitrogen or phosphorus supplies. In different P. tricornutum accessions collected worldwide, a deprivation of either nutrient triggered an accumulation of triacylglycerol, but with different time scales and magnitudes. We investigated in depth the effect of nutrient starvation on the Pt1 strain (Culture Collection of Algae and Protozoa no. 1055/3). Nitrogen deprivation was the more severe stress, triggering thylakoid senescence and growth arrest. By contrast, phosphorus deprivation induced a stepwise adaptive response. The time scale of the glycerolipidome changes and the comparison with large-scale transcriptome studies were consistent with an exhaustion of unknown primary phosphorus-storage molecules (possibly polyphosphate) and a transcriptional control of some genes coding for specific lipid synthesis enzymes. We propose that phospholipids are secondary phosphorus-storage molecules broken down upon phosphorus deprivation, while nonphosphorus lipids are synthesized consistently with a phosphatidylglycerol-to-sulfolipid and a phosphatidycholine-to-betaine lipid replacement followed by a late accumulation of triacylglycerol. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
22. Investigating mixotrophic metabolism in the model diatom Phaeodactylum tricornutum .
- Author
-
Villanova V, Fortunato AE, Singh D, Bo DD, Conte M, Obata T, Jouhet J, Fernie AR, Marechal E, Falciatore A, Pagliardini J, Le Monnier A, Poolman M, Curien G, Petroutsos D, and Finazzi G
- Subjects
- Biomass, Glycerol metabolism, Carbon metabolism, Diatoms growth & development, Diatoms metabolism, Light
- Abstract
Diatoms are prominent marine microalgae, interesting not only from an ecological point of view, but also for their possible use in biotechnology applications. They can be cultivated in phototrophic conditions, using sunlight as the sole energy source. Some diatoms, however, can also grow in a mixotrophic mode, wherein both light and external reduced carbon contribute to biomass accumulation. In this study, we investigated the consequences of mixotrophy on the growth and metabolism of the pennate diatom Phaeodactylum tricornutum , using glycerol as the source of reduced carbon. Transcriptomics, metabolomics, metabolic modelling and physiological data combine to indicate that glycerol affects the central-carbon, carbon-storage and lipid metabolism of the diatom. In particular, provision of glycerol mimics typical responses of nitrogen limitation on lipid metabolism at the level of triacylglycerol accumulation and fatty acid composition. The presence of glycerol, despite provoking features reminiscent of nutrient limitation, neither diminishes photosynthetic activity nor cell growth, revealing essential aspects of the metabolic flexibility of these microalgae and suggesting possible biotechnological applications of mixotrophy.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'., (© 2017 The Author(s).)
- Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.