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2. Perylene-derivative singlet exciton fission in water solution.

Author

Magne, Chloe, Streckaite, Simona, Boto, Roberto A., Domínguez-Ojeda, Eduardo, Gromova, Marina, Echeverri, Andrea, Brigiano, Flavio Siro, Ha-Thi, Minh-Huong, Fanckevičius, Marius, Jašinskas, Vidmantas, Quaranta, Annamaria, Pascal, Andrew A., Koepf, Matthieu, Casanova, David, Pino, Thomas, Robert, Bruno, Contreras-García, Julia, Finkelstein-Shapiro, Daniel, Gulbinas, Vidmantas, and Llansola-Portoles, Manuel J.

Published
2024
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4. Gadgets and new educational technologies: Real assistance or an obstacle?

Author

Molochkova Svetlana Alekseevna, Gromova Marina Valentinovna, Bartenev Valery Alekseevich, Borodkin Aleksander Viktorovich, and Salnikov Aleksander Mikhailovich

Subjects
distance learning, survey, higher education, technology implementation, Social Sciences
Abstract

The rapid spread of modern computer and communication technologies resulted in some global problems in society, including the adoption and rejection of such technologies in education. The COVID pandemic forced a widespread use of modern-style communications between tutors and students but unsolved problems still exist and will exist in the post-COVID era. The main goal of the paper is to find the potential borders of using modern technologies for students learning economics and business management in Russia. The authors conducted the survey in March of 2021 in the Yaroslavl Region, Russia. The main finding of the paper is the necessity of limiting the use of computer technology. The main reason for such limits is a possible decrease in students’ health and the quality of education. All the results gained by the authors are applicable in the practice of organization of educational processes for students involved in economics and business management. Probably, the results may be inapplicable for students of other fields such as medicine, art, engineers, etc.

Published
2021
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8. Correction: Perylene-derivative singlet exciton fission in water solution.

Author

Magne, Chloe, Streckaite, Simona, Boto, Roberto A., Domínguez-Ojeda, Eduardo, Gromova, Marina, Echeverri, Andrea, Brigiano, Flavio Siro, Ha-Thi, Minh-Huong, Franckevičius, Marius, Jašinskas, Vidmantas, Quaranta, Annamaria, Pascal, Andrew A., Koepf, Matthieu, Casanova, David, Pino, Thomas, Robert, Bruno, Contreras-García, Julia, Finkelstein-Shapiro, Daniel, Gulbinas, Vidmantas, and Llansola-Portoles, Manuel J.

Published
2025
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12. Stepwise Biogenesis of Subpopulations of Lipid Droplets in Nitrogen Starved Phaeodactylum tricornutum Cells

Author

Jaussaud, Antoine, Lupette, Josselin, Salvaing, Juliette, Jouhet, Juliette, Bastien, Olivier, Gromova, Marina, Maréchal, Eric, LIPID, Physiologie cellulaire et végétale (LPCV), Centre National de la Recherche Scientifique (CNRS)-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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Michigan State University [East Lansing], Michigan State University System, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), DRF Impulsion program from CEA (RMN-Biocar), ANR-11-BTBR-0008,OCEANOMICS,Biotechnologies et bioressources pour la valorisation des écosystèmes marins planctoniques(2011), ANR-15-IDEX-0002,UGA,IDEX UGA(2015), ANR-10-LABX-0004,CeMEB,Mediterranean Center for Environment and Biodiversity(2010), ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Energy-Michigan State University Plant Research Laboratory, Michigan State University System-Michigan State University System, Magnetic Resonance (RM), Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), ANR-11-BTBR-0008/11-BTBR-0008,OCEANOMICS,Biotechnologies et bioressources pour la valorisation des écosystèmes marins planctoniques(2011), ANR-15-IDEX-02,UGA,IDEX UGA(2016), ANR–10–LABEX–04 ,GRAL,Labex, and ANR-17-EURE-0003,University Grenoble Alpes graduate school

Subjects
lipids, Phaeodactylum, lipid droplet, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Plant Science, [SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC], [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, Triacylglycerol, Original Research, diatoms
Abstract

International audience; Diatoms are unicellular heterokonts, living in oceans and freshwaters, exposed to frequent environmental variations. They have a sophisticated membrane compartmentalization and are bounded by a siliceous cell-wall. Formation of lipid droplets (LDs), filled with triacylglycerol (TAG), is a common response to stress. The proteome of mature-LDs from Phaeodactylum tricornutum highlighted the lack of proteins involved in early-LD formation, TAG biosynthesis or LD-to-LD connections. These features suggest that cytosolic LDs might reach a size limit. We analyzed the dynamics of LD formation in P. tricornutum (Pt1 8.6; CCAP 1055/1) during 7 days of nitrogen starvation, by monitoring TAG by mass spectrometry-based lipidomics, and LD radius using epifluorescence microscopy and pulse field gradient nuclear magnetic resonance. We confirmed that mature LDs reach a maximal size. Based on pulse field gradient nuclear magnetic resonance, we did not detect any LD-LD fusion. Three LD subpopulations were produced, each with a different maximal size, larger-sized LDs (radius 0.675 ± 0.125 µm) being generated first. Mathematical modeling showed how smaller LDs are produced once larger LDs have reached their maximum radius. In a mutant line having larger cells, the maximal size of the first LD subpopulation was higher (0.941 ± 0.169 µm), while the principle of stepwise formation of distinct LD populations was maintained. Results suggest that LD size is determined by available cytosolic space and sensing of an optimal size reached in the previous LD subpopulation. Future perspectives include the unraveling of LD-size control mechanisms upon nitrogen shortage. This study also provides novel prospects for the optimization of oleaginous microalgae for biotechnological applications.

Published
2020
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13. Comparative analysis of rotor system models with auto-balancers of ball, roller and pendulum type

Author

Filimonikhin, Gennadiy, Strautmanis, Guntis, Gorbenko, Alexander, Mezitis, Mareks, Filimonikhina, Irina, Gromova, Marina, Filimonikhin, Gennadiy, Strautmanis, Guntis, Gorbenko, Alexander, Mezitis, Mareks, Filimonikhina, Irina, and Gromova, Marina

Abstract

In the paper, differential equations of motion are derived for a plane model of rotor on anisotropic viscoelastic supports, which is balanced by a ball (roller) or pendulum auto-balancer. The forces of gravity and viscous resistance to the motion of compensating cargoes are taken into account. Cases of an unbalanced rotor motion from engine torque with a variable and constant angular velocity are considered. Using a comparative analysis of the motion equations structure it is established cases in which it is possible to build a unified theory of the specified auto-balancer types and apply the results obtained for one auto-balancer type to other types.

Published
2020

14. Применение правил перспективы в изобразительном искусстве. Анализ картин художников

Author

Gromova Marina Sergeevna and Semenova Nina Konstantinovna

Subjects
произведение изобразительного искусства, линейная перспектива, анализ картины
Abstract

статья посвящена анализу произведений изобразительного искусства с точки зрения применения правил линейной перспективы. Выявлены основные приемы, которые используют художники для создания желаемого эффекта от восприятия картины.

Published
2018

16. Study of the area of attraction of the auto-balancing mode in a ball-type automatic balancing device with a horizontal axis of rotation

Author

Strautmanis, Guntis, Mezitis, Mareks, Strautmane, Valentina, Gorbenko, Alexander, Shchukins, Igors, Gromova, Marina, Strautmanis, Guntis, Mezitis, Mareks, Strautmane, Valentina, Gorbenko, Alexander, Shchukins, Igors, and Gromova, Marina

Abstract

It is known that automatic balancing devices are capable of reducing vibrations in rotary systems in a superresonance velocity zone. However, the effectiveness of automatic balancing devices is related to the necessity of accelerating compensating masses. To ensure the acceleration of compensating masses from standstill to the operating speed of the rotor, they need to be provided some initial velocity. The value of this velocity is influenced by the parameters of the elastic suspension of the rotor, the geometrical parameters of the automatic balancer, the coefficient of rolling friction between the housing and the compensating mass, etc. The work is devoted to the study of a horizontal rotor model with an automatic balancer with one compensating mass, in particular the issue on the influence of the coefficient of viscous friction on the value of the area of attraction of the auto-balancing mode.

Published
2019

17. Применение правил перспективы в изобразительном искусстве. Анализ картин художников

Author

Громова Марина Сергеевна, Институт искусств и художественного образования ФГБОУ ВО «Владимирский государственный университет им. А.Г. и Н.Г. Столетовых», Gromova Marina Sergeevna, Institute of arts and art educationFSBEI of HE "Vladimir State University named after A.G. and V.G. Stoletovy", Семенова Нина Константиновна, Semenova Nina Konstantinovna, Громова Марина Сергеевна, Институт искусств и художественного образования ФГБОУ ВО «Владимирский государственный университет им. А.Г. и Н.Г. Столетовых», Gromova Marina Sergeevna, Institute of arts and art educationFSBEI of HE "Vladimir State University named after A.G. and V.G. Stoletovy", Семенова Нина Константиновна, and Semenova Nina Konstantinovna

Abstract

Статья посвящена анализу произведений изобразительного искусства с точки зрения применения правил линейной перспективы. Выявлены основные приемы, которые используют художники для создания желаемого эффекта от восприятия картины.

Published
2018

19. Biological decontamination of radionuclides in industrial and environmental water using a new highly radioresistant microalga

Author

Rivasseau, Corinne, Saint Cyr, Diane de Gouvion, Atteia, Ariane, Gromova, Marina, Fahri, Emmanuel, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Bioénergétique et Ingénierie des Protéines (BIP ), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Direction des Sciences de la Matière, Institut LAUE LANGEVIN, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
environmental water, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Depollution, [SDV]Life Sciences [q-bio], nuclear industry, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, decontamination, radionuclide, microalga, biotechnology
Abstract

International audience; Nuclear energy technologies generate radioactive and chemically toxic compounds including mainly carbon-14 and radioactive metals. Treatment processes rely on physico-chemical methods, which, though efficient and robust, do not completely remove carbon-14 and are not adapted to large environmental volumes. Alternative technologies are needed to reduce radioactive releases in aqueous effluents or to clean-up accidentally contaminated water. Biological remediation technologies may constitute an interesting alternative. We recently isolated a new microalga from a nuclear facility, Coccomyxa actinabiotis, which withstands huge ionizing radiation doses, up to 20,000 Gy. This microalga very efficiently and rapidly accumulates most of the metallic radionuclides contained in nuclear effluents including 238U, 137Cs, 110mAg, 60Co, 54Mn and 65Zn with decontamination rates above 90%. It decontaminates more than 85% of carbon-14 in a few hours. This alga is an excellent candidate for new biotechnology methods. The process feasibility was demonstrated at real-scale for in situ decontamination and pilote-scale for remote water treatment. These algae-based methods could be used inside nuclear facilities, where they would complement or replace conventional methods and reduce the volume of radioactive waste, at the exit point from nuclear facilities to reduce radioactive emissions into the environment, or for the decontamination of accidentally polluted water.

Published
2015

20. KOMPETENTNOSTNY APPROACH IN THE ASSESSMENT OF RESULTS OF ACTIVITY OF TEACHERS OF ADDITIONAL EDUCATION OF CHILDREN

Author

Gromova Marina Valentinovna

Subjects
lcsh:Social Sciences, lcsh:H
Abstract

Aim. Justification of need of application of a kompetentnostny approach in an assessment of results of activity of teachers of additional education of children was the main objective of carried-out research. Method and methodology of carrying out work. Sociological poll of heads of educational institutions of additional education of children in the Yaroslavl region in the form of questioning was carried out; the content analysis of scientific literature on this perspective is carried out. Results. As a result of research the materials confirming need of improvement of developed system of an assessment of results of activity of teachers of additional education of children on the basis of models of competences are received Scope of results. Results of research can be applied in the human resource management sphere in educational institutions of additional education of children.

Published
2012

21. «Эффективный контракт» как фактор развития образовательных организаций дополнительного образования детей

Author

Громова Марина Валентиновна, Ярославский филиал АОЧУ ВО «Московский финансово-юридический университет МФЮА», Gromova Marina Valentinovna, Громова Марина Валентиновна, Ярославский филиал АОЧУ ВО «Московский финансово-юридический университет МФЮА», and Gromova Marina Valentinovna

Abstract

в статье рассматривается роль и значение «эффективного контракта» как социально-правовой предпосылки развития образовательных организаций дополнительного образования детей. Перечисляются мероприятия по повышению эффективности и качеству услуг в сфере дополнительного образования детей. Сделаны выводы о повышении престижности и привлекательности профессии педагога дополнительного образования детей, а также качества предоставляемых услуг в результате реализация эффективного контракта для системы дополнительного образования детей.

Published
2015

23. Spectroscopic investigation of ionizing-radiation tolerance of a Chlorophyceae green micro-alga

Author

Farhi, Emmanuel, Rivasseau, Corinne, Gromova, Marina, Compagnon, Estelle, Marzloff, Vincent, Ollivier, Jacques, Boisson, Anne-Marie, Bligny, Richard, Natali, Francesca, Russo, Daniela, Couté, Alain, Institut Laue-Langevin (ILL), ILL, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), ESPCI ParisTech, Laboratoire de Cryptogamie, Museum National d'Histoire Naturelle, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL), Ecosystèmes et Interactions Toxiques, Muséum national d'Histoire naturelle (MNHN)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-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)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
ionizing irradiation, organic acid, Algae, microalgae, metabolite, nuclear magnetic resistance, water cooling system, NMR, radioresistance, Chlorophyceae, carbohydrate, [SDV.TOX]Life Sciences [q-bio]/Toxicology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, nuclear reactor, metabolism, amino acid, mass spectrometry
Abstract

International audience; Micro-organisms living in extreme environments are captivating in the peculiar survival processes they have developed. Deinococcus radiodurans is probably the most famous radio-resistant bacteria. Similarly, a specific ecosystem has grown in a research reactor storage pool, and has selected organisms which may sustain radiative stress. An original green micro-alga which was never studied for its high tolerance to radiations has been isolated. It is the only autotrophic eukaryote that develops in this pool, although contamination possibilities coming from outside are not unusual. Studying what could explain this irradiation tolerance is consequently very interesting. An integrative study of the effects of irradiation on the micro-algae physiology, metabolism, internal dynamics, and genomics was initiated. In the work presented here, micro-algae were stressed with irradiation doses up to 20 kGy (2 Mrad), and studied by means of nuclear magnetic resonance, looking for modifications in the metabolism, and on the IN13 neutron backscattering instrument at the ILL, looking for both dynamics and structural macromolecular changes in the cells.

Published
2008

24. Growth Mechanism and Surface State of CuInS2 Nanocrystals Synthesized with Dodecanethiol.

Author

Gromova, Marina, Lefrançois, Aurélie, Vaure, Louis, Agnese, Fabio, Aldakov, Dmitry, Maurice, Axel, Djurado, David, Lebrun, Colette, de Geyer, Arnaud, Schülli, Tobias U., Pouget, Stéphanie, and Reiss, Peter

Subjects
*NANOCRYSTALS, *TERNARY alloys, *CHALCOGENIDES, *OPTOELECTRONICS, *X-ray diffraction
Abstract

Ternary metal chalcogenide nanocrystals (NCs) offer exciting opportunities as novel materials to be explored on the nanoscale showing optoelectronic properties tunable with size and composition. CuInS2 (CIS) NCs are the most widely studied representatives of this family as they can be easily prepared with good size control and in high yield by reacting the metal precursors (copper iodide and indium acetate) in dodecanethiol (DDT). Despite the widespread use of this synthesis method, both the reaction mechanism and the surface state of the obtained NCs remain elusive. Here, we perform in situ X-ray diffraction using synchrotron radiation to monitor the pre- and postnucleation stages of the formation of CIS NCs. SAXS measurements show that the reaction intermediate formed at 100 °C presents a periodic lamellar structure with a characteristic spacing of 34.9 Å. WAXS measurements performed after nucleation of the CIS NCs at 230 °C demonstrate that their growth kinetics depend on the degree of precursor conversion achieved in the initial stage at 100 °C. NC formation requires the cleavage of S-C bonds. We reveal by means of combined 1D and 2D proton and carbon NMR analyses that the generated dodecyl radicals lead to the formation of a new thioether species R-S-R. The latter is part of a ligand double layer, which consists of dynamically bound dodecanethiolate ligands as well as of head-to-tail bound R-S-R molecules. This ligand double layer and a high ligand density (3.6 DDT molecules per nm²) are at the origin of the apparent difficulty to functionalize the surface of CIS NCs obtained with the DDT method. [ABSTRACT FROM AUTHOR]

Published
2017
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25. Enhanced Charge Separation in Ternary P3HT/PCBM/CuInS2 Nanocrystals Hybrid Solar Cells

Author

Lefrançois, Aurélie, primary, Luszczynska, Beata, additional, Pepin-Donat, Brigitte, additional, Lombard, Christian, additional, Bouthinon, Benjamin, additional, Verilhac, Jean-Marie, additional, Gromova, Marina, additional, Faure-Vincent, Jérôme, additional, Pouget, Stéphanie, additional, Chandezon, Frédéric, additional, Sadki, Saïd, additional, and Reiss, Peter, additional

Published
2015
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26. In Plants, 3-O-Methylglucose Is Phosphorylated by Hexokinase But Not Perceived as a Sugar1

Author

Cortès, Sandra, Gromova, Marina, Evrard, Adeline, Roby, Claude, Heyraud, Alain, Rolin, Dominique B., Raymond, Philippe, and Brouquisse, Renaud M.

Subjects
Carbon Isotopes, Magnetic Resonance Spectroscopy, Cell Respiration, Arabidopsis, Glucose-6-Phosphate, Phosphorus Isotopes, Plant Development, Plants, Plant Roots, Zea mays, Carbon, Kinetics, Solanum lycopersicum, Hexokinase, Endopeptidases, 3-O-Methylglucose, Carbohydrate Metabolism, Phosphorylation, Research Article, Peptide Hydrolases, Plant Proteins, Signal Transduction
Abstract

In plants, sugars are the main respiratory substrates and important signaling molecules in the regulation of carbon metabolism. Sugar signaling studies suggested that sugar sensing involves several key components, among them hexokinase (HXK). Although the sensing mechanism of HXK is unknown, several experiments support the hypothesis that hexose phosphorylation is a determining factor. Glucose (Glc) analogs transported into cells but not phosphorylated are frequently used to test this hypothesis, among them 3-O-methyl-Glc (3-OMG). The aim of the present work was to investigate the effects and fate of 3-OMG in heterotrophic plant cells. Measurements of respiration rates, protein and metabolite contents, and protease activities and amounts showed that 3-OMG is not a respiratory substrate and does not contribute to biosynthesis. Proteolysis and lipolysis are induced in 3-OMG-fed maize (Zea mays L. cv DEA) roots in the same way as in sugar-starved organs. However, contrary to the generally accepted idea, phosphorous and carbon nuclear magnetic resonance experiments and enzymatic assays prove that 3-OMG is phosphorylated to 3-OMG-6-phosphate, which accumulates in the cells. Insofar as plant HXK is involved in sugar sensing, these findings are discussed on the basis of the kinetic properties because the catalytic efficiency of HXK isolated from maize root tips is five orders of magnitude lower for 3-OMG than for Glc and Man.

Published
2003

34. Toward Arabidopsis thaliana hydrophilic metabolome: assessment of extraction methods and quantitative 1H NMR.

Author

Gromova, Marina and Roby, Claude

Subjects
*ARABIDOPSIS thaliana, *CELL culture, *PERCHLORIC acid, *NUCLEAR magnetic resonance spectroscopy, *FREEZE-drying
Abstract

Our goal was to establish the hydrophilic metabolome of heterotrophic Arabidopsis thaliana cells grown in suspension, a cellular model of plant sink tissues. Water-soluble metabolites were extracted using four protocols: perchloric acid, boiling ethanol, methanol and methanol/chloroform (M/Chl). They were detected and quantified using 1H nuclear magnetic resonance (NMR) spectroscopy at 400 MHz. Extraction yields and reproducibility of the extraction methods were investigated. The effects of cell harvest protocol, cell grinding and lyophilization and storage conditions on the measured metabolic profiles were also studied. These quantitative studies demonstrated for the first time that the four extraction protocols commonly used do lead to quite similar molecular compositions as analyzed by 1H NMR. The M/Chl method proved effective and reliable to prepare series of physiologically significant extracts from plant cells for 1H NMR analysis. Reproducibility of the detected metabolome was assessed over long periods of time by analyzing a large number of separate extracts prepared from independent cultures. Larger variations in the NMR metabolite profiles could be correlated to changes in physiological parameters of the culture medium. Quantitative resolved 1H NMR of cell extracts proved to be robust and reliable for routine metabolite profiling of plant cell cultures. [ABSTRACT FROM AUTHOR]

Published
2010
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35. Dynamic NMR study of rotational isomerism in the carbanion of <TOGGLE>p</TOGGLE>-trifluoromethanesulfonylbenzyltriflone in aprotic solvents

Author

Gromova, Marina, Béguin, Claude G., Goumont, Régis, Faucher, Nicolas, Tordeux, Marc, and Terrier, François

Abstract

Rotational isomerism in the conjugate carbanion of p-trifluoromethanesulfonylbenzyltriflone was studied by dynamic NMR spectroscopy (1H, 13C). Treatment of the experimental spectra affords the activation parameters of the processes. The activation enthalpies (~48 kJ mol−1) for the rotational barrier around the CAr—Cα carbon– carbon bond are indicative of a relatively weak π-order of this bond and are nearly identical in the three dipolar aprotic solvents studied, namely acetonitrile, dimethyl sulfoxide and acetone. Changes in the rates of the conformation exchange around the CAr—Cα bond are mainly a reflection of the solvent dependence of the entropy change (from almost 0 in acetonitrile, to −8 in DMSO and −13 J K−1 mol−1 in acetone). These data are discussed in relation to information on the electronic density distribution, as obtained from an analysis of the 13C chemical shift of the anion of the benzyltriflone. Copyright © 2000 John Wiley & Sons, Ltd.

Published
2000

36. Quantitative 2D EXSY and Dynamic <SUP>19</SUP>F-NMR Studies of the Dynamic Behaviour of the Bidentate Chelate Complex Ga(fox)<INF>3</INF> (fox = 5-fluoro-8-hydroxyquinoline)

Author

Gromova, Marina, Jarjayes, Olivier, Hamman, Sylvain, Nardin, Robert, Béguin, Claude, and Willem, Rudolph

Abstract

The rates of intramolecular rearrangement of the meridional isomer of the metal tris-chelate complex [Ga(fox)3, fox = 5-fluoro-8-hydroxyquinoline] in DMF solution were measured using 1D NMR line shape analysis and 2D EXSY spectra. The rates of exchange kab, kbc and kac between the three non-equivalent ligands a, b and c were determined. The values of the activation parameters were obtained. ΔH‡ was 70.6 kJ mol–1 for all the rate constants. ΔS‡ was different in each of the three cases: ΔS‡ab, ΔS‡bc and ΔS‡ac were 27.7, 28.5 and 34.6 J K–1 mol–1 respectively. The interpretation of these data was related to the discrimination of different twist processes (Bailar and Rây–Dutt) for intramolecular rearrangement of the tris-chelate complex.

Published
2000
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37. Direct effect of heavy ions and electrons on 2′-deoxyguanosine in the solid state

Author

Gromova, Marina, Nardin, Robert, and Cadet, Jean

Abstract

Attempts have been made in this work to gain insights into the mechanisms of the formation of degradation products arising from the exposure of 2′-deoxyguanosine (dGuo) in the solid state to O7+ heavy ions of 10.6 MeV u–1 (LET 4;≈ 4;500 keV µm–1). The main decomposition products of dGuo have been isolated by reversed-phase high performance liquid chromatography and characterized by extensive spectroscopic (1H and 13C NMR, mass spectrometry, UV) measurements. Reaction mechanisms, involving the transient formation of sugar and purine radical, are proposed to explain the generation of the heavy ion-mediated degradation products. Another major objective of the present work is the comparison of heavy ion-induced modifications of 2′-deoxyguanosine with those produced by lower LET radiation. For this purpose, the samples of 2′-deoxyguanosine were exposed in the solid state to electrons of 2 MeV (LET 4;≈ 4;0.18 keV µm–1). It may be inferred from the results of the qualitative and semi-quantitative comparison that the modifications of the sugar moiety are more efficiently induced by heavy ions than by electrons.

Published
1998
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38. Enhanced Charge Separation in Ternary P3HT/PCBM/CuInS2 Nanocrystals Hybrid Solar Cells.

Author

Lombard, Christian, Faure-Vincent, Jérôme, Chandezon, Frédéric, Pouget, Stéphanie, Sadki, Saïd, Bouthinon, Benjamin, Lefrançois, Aurélie, Pepin-Donat, Brigitte, Verilhac, Jean-Marie, Reiss, Peter, Luszczynska, Beata, and Gromova, Marina

Subjects
ELECTRONIC excitation, NANOCRYSTALS, POLYTHIOPHENES, FULLERENE derivatives, COPPER compounds, HYBRID solar cells
Abstract

Geminate recombination of bound polaron pairs at the donor/acceptor interface is one of the major loss mechanisms in organic bulk heterojunction solar cells. One way to overcome Coulomb attraction between opposite charge carriers and to achieve their full dissociation is the introduction of high dielectric permittivity materials such as nanoparticles of narrow band gap semiconductors. We selected CuInS2 nanocrystals of 7.4 nm size, which present intermediate energy levels with respect to poly(3-hexylthiophene) (P3HT) and Phenyl-C61-butyric acid methyl ester (PCBM). Efficient charge transfer from P3HT to nanocrystals takes place as evidenced by light-induced electron spin resonance. Charge transfer between nanocrystals and PCBM only occurs after replacing bulky dodecanethiol (DDT) surface ligands with shorter 1,2-ethylhexanethiol (EHT) ligands. Solar cells containing in the active layer a ternary blend of P3HT:PCBM:CuInS2-EHT nanocrystals in 1:1:0.5 mass ratio show strongly improved short circuit current density and a higher fill factor with respect to the P3HT:PCBM reference device. Complementary measurements of the absorption properties, external quantum efficiency and charge carrier mobility indicate that enhanced charge separation in the ternary blend is at the origin of the observed behavior. The same trend is observed for blends using the glassy polymer poly(triarylamine) (PTAA). [ABSTRACT FROM AUTHOR]

Published
2015
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39. Resistance to irradiation of micro-algae growing in the storage pools of a nuclear reactor investigated by NMR and neutron spectroscopies

Author

Rivasseau, Corinne, Farhi, Emmanuel, Gromova, Marina, Ollivier, Jacques, and Bligny, Richard

Abstract

A green Chlorophycean micro-alga surviving high irradiation doses has been discovered in the storage pools of a nuclear reactor. Investigating the mechanisms sustaining its properties is of peculiar interest. Metabolic impact of irradiation on the micro-alga as well as structural macromolecular impact were investigated using nuclear magnetic resonance and neutron backscattering spectroscopy. Carbohydrate, amino acid and organic acid content studied as a function of the irradiation dose revealed an intense protein repair activity. Resilience was extracted according to irradiation dose and compared to that of other extremophile species.

Published
2010
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40. Correction: Perylene-derivative singlet exciton fission in water solution.

Author

Magne C, Streckaite S, Boto RA, Domínguez-Ojeda E, Gromova M, Echeverri A, Brigiano FS, Ha-Thi MH, Franckevičius M, Jašinskas V, Quaranta A, Pascal AA, Koepf M, Casanova D, Pino T, Robert B, Contreras-García J, Finkelstein-Shapiro D, Gulbinas V, and Llansola-Portoles MJ

Abstract

[This corrects the article DOI: 10.1039/D4SC04732J.]., (This journal is © The Royal Society of Chemistry.)

Published
2024
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41. Stepwise Biogenesis of Subpopulations of Lipid Droplets in Nitrogen Starved Phaeodactylum tricornutum Cells.

Author

Jaussaud A, Lupette J, Salvaing J, Jouhet J, Bastien O, Gromova M, and Maréchal E

Abstract

Diatoms are unicellular heterokonts, living in oceans and freshwaters, exposed to frequent environmental variations. They have a sophisticated membrane compartmentalization and are bounded by a siliceous cell-wall. Formation of lipid droplets (LDs), filled with triacylglycerol (TAG), is a common response to stress. The proteome of mature-LDs from Phaeodactylum tricornutum highlighted the lack of proteins involved in early-LD formation, TAG biosynthesis or LD-to-LD connections. These features suggest that cytosolic LDs might reach a size limit. We analyzed the dynamics of LD formation in P. tricornutum (Pt1 8.6; CCAP 1055/1) during 7 days of nitrogen starvation, by monitoring TAG by mass spectrometry-based lipidomics, and LD radius using epifluorescence microscopy and pulse field gradient nuclear magnetic resonance. We confirmed that mature LDs reach a maximal size. Based on pulse field gradient nuclear magnetic resonance, we did not detect any LD-LD fusion. Three LD subpopulations were produced, each with a different maximal size, larger-sized LDs (radius 0.675 ± 0.125 µm) being generated first. Mathematical modeling showed how smaller LDs are produced once larger LDs have reached their maximum radius. In a mutant line having larger cells, the maximal size of the first LD subpopulation was higher (0.941 ± 0.169 µm), while the principle of stepwise formation of distinct LD populations was maintained. Results suggest that LD size is determined by available cytosolic space and sensing of an optimal size reached in the previous LD subpopulation. Future perspectives include the unraveling of LD-size control mechanisms upon nitrogen shortage. This study also provides novel prospects for the optimization of oleaginous microalgae for biotechnological applications., (Copyright © 2020 Jaussaud, Lupette, Salvaing, Jouhet, Bastien, Gromova and Maréchal.)

Published
2020
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