Search

Your search keyword '"MESH: Light"' showing total 16 results
Start Over Descriptor "MESH: Light" Publication Year Range Last 10 years
16 results on '"MESH: Light"'

1. Extra kinetic dimensions for label discrimination

Author

Raja Chouket, Agnès Pellissier-Tanon, Aliénor Lahlou, Ruikang Zhang, Diana Kim, Marie-Aude Plamont, Mingshu Zhang, Xi Zhang, Pingyong Xu, Nicolas Desprat, Dominique Bourgeois, Agathe Espagne, Annie Lemarchand, Thomas Le Saux, Ludovic Jullien, Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sony Computer Science Laboratory Paris (SONY CSL-Paris), Sony France SA, Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, ABCD : Biophysique des Biomolécules, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de biologie de l'ENS Paris (IBENS), Département de Biologie - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie structurale (IBS - UMR 5075), 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)-Université Grenoble Alpes (UGA), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-10-INBS-0004,France-BioImaging,Développment d'une infrastructure française distribuée coordonnée(2010), ANR-11-EQPX-0029,MORPHOSCOPE 2,Imagerie et reconstruction multiéchelles de la morphogenèse. (Plateforme d'innovation technologique et méthodologique pour l'imagerie in vivo et la reconstruction des dynamiques multiéchelles de la morphogenèse)(2011), ANR-10-IDEX-0001,PSL,Paris Sciences et Lettres(2010), ANR-10-LABX-0031,IPGG_LABEX,Pierre-Gilles de Gennes Institute for microfluidics(2010), ANR-17-CE11-0047,Cryo-PALM,Microscopie super-résolution par localisation de molécules uniques à température cryogénique.(2017), ANR-19-CE11-0005,HIGHLIGHT,Imagerie sensible à la phase de nombreux marqueurs réversiblement photocommutables en lumière modulée(2019), ANR-19-CE29-0003,dISCern,Le croisement intersystème dans les protéines fluorescentes: un nouveau mécanisme pour la microscopie de fluorescence confocale à contraste dynamique(2019), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
MESH: Optical Imaging, Multidisciplinary, Light, MESH: Kinetics, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Optical Imaging, General Physics and Astronomy, MESH: Microscopy, Fluorescence, General Chemistry, MESH: Fluorescent Dyes, General Biochemistry, Genetics and Molecular Biology, MESH: Light, Kinetics, Microscopy, Fluorescence, [CHIM]Chemical Sciences, Fluorescent Dyes
Abstract

Due to its sensitivity and versatility, fluorescence is widely used to detect specifically labeled biomolecules. However, fluorescence is currently limited by label discrimination, which suffers from the broad full width of the absorption/emission bands and the narrow lifetime distribution of the bright fluorophores. We overcome this limitation by introducing extra kinetic dimensions through illuminations of reversibly photoswitchable fluorophores (RSFs) at different light intensities. In this expanded space, each RSF is characterized by a chromatic aberration-free kinetic fingerprint of photochemical reactivity, which can be recovered with limited hardware, excellent photon budget, and minimal data processing. This fingerprint was used to identify and discriminate up to 20 among 22 spectrally similar reversibly photoswitchable fluorescent proteins (RSFPs) in less than 1s. This strategy opens promising perspectives for expanding the multiplexing capabilities of fluorescence imaging.

Published
2022

2. Time-resolved serial femtosecond crystallography on fatty-acid photodecarboxylase: lessons learned

Author

Hadjidemetriou, K., Coquelle, N., Barends, T., De, E., Zitter, Schlichting, I., Colletiera, J., Weik, M., Institut de biologie structurale (IBS - UMR 5075), 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)-Université Grenoble Alpes (UGA), Max Planck Institute for Medical Research [Heidelberg], and Max-Planck-Gesellschaft

Subjects
photoenzymes, serial femtosecond crystallography, Crystallography, Light, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Lasers, Spectrum Analysis, structure-factor extrapolation, MESH: Crystallography, Fatty Acids, MESH: Spectrum Analysis, Crystallography, X-Ray, MESH: Crystallography, X-Ray, MESH: Light, MESH: Fatty Acids, Structural Biology, fatty-acid photodecarboxylase, time-resolved crystallography, MESH: Lasers
Abstract

Upon absorption of a blue-light photon, fatty-acid photodecarboxylase catalyzes the decarboxylation of free fatty acids to form hydrocarbons (for example alkanes or alkenes). The major components of the catalytic mechanism have recently been elucidated by combining static and time-resolved serial femtosecond crystallography (TR-SFX), time-resolved vibrational and electronic spectroscopies, quantum-chemical calculations and site-directed mutagenesis [Sorigué et al. (2021), Science, 372, eabd5687]. The TR-SFX experiments, which were carried out at four different picosecond to microsecond pump–probe delays, yielded input for the calculation of Fourier difference maps that demonstrated light-induced decarboxylation. Here, some of the difficulties encountered during the experiment as well as during data processing are highlighted, in particular regarding space-group assignment, a pump-laser power titration is described and data analysis is extended by structure-factor extrapolation of the TR-SFX data. Structure refinement against extrapolated structure factors reveals a reorientation of the generated hydrocarbon and the formation of a photoproduct close to Cys432 and Arg451. Identification of its chemical nature, CO2 or bicarbonate, was not possible because of the limited data quality, which was assigned to specificities of the crystalline system. Further TR-SFX experiments on a different crystal form are required to identify the photoproducts and their movements during the catalytic cycle.

Published
2022

3. mEos4b photoconversion efficiency depends on laser illumination conditions used in PALM

Author

Jip Wulffele, Daniel Thédié, Oleksandr Glushonkov, Dominique Bourgeois, Institut de biologie structurale (IBS - UMR 5075), 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)-Université Grenoble Alpes (UGA), M4D, ANR-17-CE11-0047,Cryo-PALM,Microscopie super-résolution par localisation de molécules uniques à température cryogénique.(2017), ANR-20-CE11-0013,STABLE-FP,Nouvelle génération de protéines fluorescentes ultrastables pour la microscopie quantitative super-résolution(2020), and ANR-16-CE11-0016,DIVinHD,Imagerie super-résolue de la division bactérienne(2016)

Subjects
Microscopy, MESH: Microscopy, Light, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Lasers, Green Fluorescent Proteins, MESH: Lighting, MESH: Light, Luminescent Proteins, MESH: Green Fluorescent Proteins, MESH: Lasers, General Materials Science, MESH: Luminescent Proteins, Physical and Theoretical Chemistry, Lighting
Abstract

Green-to-red photoconvertible fluorescent proteins (PCFPs) are widely employed as markers in photoactivated localization microscopy (PALM). However, their highly complex photophysical behavior complicates their usage. The fact that only a limited fraction of a PCFP ensemble can form the photoconverted state upon near-UV light illumination, termed photoconversion efficiency (PCE), lowers the achievable spatial resolution in PALM and creates undercounting errors in quantitative counting applications. Here, we show that the PCE of mEos4b is not a fixed property of this PCFP, but strongly depends on illumination conditions. Attempts to reduce long-lived blinking in red mEos4b by application of 488 nm light leads to a reduction of the PCE. Furthermore, the PCE of mEos4b strongly depends on the applied 405-nm power density. A refined photophysical model of mEos4b accounts for the observed effects, involving nonlinear green-state photobleaching upon violet light illumination favored by photon absorption by a putative radical dark state.TOC GRAPHICS

Published
2022

4. Metal accumulation, biochemical and behavioral responses on the Mediterranean clams Ruditapes decussatus exposed to two photocatalyst nanocomposites (TiO2 NPs and AuTiO2NPs)

Author

Olivier Joubert, David Sheehan, Wiem Saidani, Hamouda Beyrem, Mouhamed Dellali, Amine Mezni, Badreddine Sellami, Abdelhafidh Khazri, Institut Jean Lamour (IJL), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Gill, [SDV]Life Sciences [q-bio], Health, Toxicology and Mutagenesis, MESH: Bivalvia, 010501 environmental sciences, medicine.disease_cause, 01 natural sciences, chemistry.chemical_compound, Ruditapes decussatus, MESH: Behavior, Animal, Biomonitoring, MESH: Animals, 0303 health sciences, MESH: Metal Nanoparticles, biology, Chemistry, Malondialdehyde, MESH: Water Pollutants, Chemical, MESH: Titanium, Catalase, Environmental chemistry, Toxicity, MESH: Gold, MESH: Hydrogen Peroxide, animal structures, AuTiO(2)NPs, MESH: Malondialdehyde, Aquatic Science, Superoxide dismutase, 03 medical and health sciences, MESH: Catalase, medicine, 14. Life underwater, TiO(2) NPs, MESH: Neurotoxins, 030304 developmental biology, 0105 earth and related environmental sciences, MESH: Antioxidants, MESH: Nanocomposites, MESH: Acetylcholinesterase, MESH: Catalysis, MESH: Light, Bioavailability, Oxidative stress, 13. Climate action, MESH: Nitric Oxide, MESH: Biomarkers, biology.protein, MESH: Gastrointestinal Tract, MESH: Gills, Biomarkers
Abstract

International audience; Nanoparticle decoration with noble metal represents a promising alternative to improve their photocatalytic and photovoltaic properties. However, toxicity can be influenced by such modification, as the bioavailability of these substances may be influenced. To understand how decoration influences the NP impacts in marine ecosystems, we exposed suspension-feeding clams, Ruditapes decussatus, to two photocatalyst nanocomposites, TiO2 NPs and AuTiO2 NPs, over 2 concentrations, 50 μg L-1and 100 μg L-1, in a laboratory experiment. Accumulation of Au and Ti in gills and digestive gland was noted in clams after exposure to TiO2 NPs and AuTiO2 NPs using inductively coupled plasma optic emission spectroscopy (ICP-OES). TiO2 and AuTiO2 NPs alter the behavior of the clams Ruditapes decussatus by reducing filtration and respiration rates. Furthermore, the highest concentration of TiO2NPs induces an overproduction of H2O2 in gills and digestive gland and NO production only in gills. Superoxide dismutase (SOD), Catalase (CAT), Glutathione-S-transferase (GST) and acetylcholinesterase (AChE) activities were induced in gills and digestives gland in concentration and nanocomposite type dependent manner. Decorated form presented higher Malondialdehyde (MDA) levels in gills and digestive gland than the undecorated form, suggesting different mechanisms of action that may be mediated through oxidative stress. In conclusion, the considered parameters could represent reliable biomarkers for the assessment of NP toxicity on R. decussatus as biological biomonitoring model. In addition, based on the obtained results, nanoparticle decoration influences the toxicity of metal nanoparticles in marine organism.

Published
2019

5. Morphological bases of phytoplankton energy management and physiological responses unveiled by 3D subcellular imaging

Author

Guy Schoehn, Clarisse Uwizeye, Gilles Curien, Rachel Templin, Samuel C. Zeeman, Yannick Schwab, Davide Dal Bo, Denis Falconet, Fabien Chevalier, Serena Flori, Christine Moriscot, Florence Courtois, Claire Seydoux, Jean-Baptiste Keck, Benoit Gallet, Johan Decelle, Nicole L. Schieber, Pierre-Henri Jouneau, Giovanni Finazzi, Guillaume Allorent, 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), Photosymbiose, 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), Light Photosynthesis & Metabolism (Photosynthesis), Institut de biologie structurale (IBS - UMR 5075), Calcul des Variations, Géométrie, Image (CVGI), Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Cell Biology and Cell Biophysics Unit, European Molecular Biology Laboratory, European Molecular Biology Laboratory [Grenoble] (EMBL), Department of Biology [ETH Zürich] (D-BIOL), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Défi X-Life grant from CNRS, CEA DRFimpulsion FIB-Bioprogram, Auvergne-Rhône-Alpes Region, Fondation Recherche Medicale (FRM), FEDER and the GIS-Infrastructures en Biologie Santé et Agronomie (IBiSA), ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010), ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017), ANR-17-CE05-0029,MoMix,Modélisation de la Mixotrophie chez l'algue extrêmophile Galdieria sulphuraria(2017), ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), ANR-15-IDEX-0002,UGA,IDEX UGA(2015), European Project: 833184, ChloroMito, and European Project: 654248,H2020,H2020-INFRADEV-1-2014-1,CORBEL(2015)

Subjects
0106 biological sciences, 0301 basic medicine, Cell biology, Light, Bioenergetics, MESH: Mitochondria, Acclimatization, Science, General Physics and Astronomy, MESH: Acclimatization, MESH: Imaging, Three-Dimensional, Cellular imaging, Photosynthesis, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Pyrenoid, MESH: Microalgae, 03 medical and health sciences, Imaging, Three-Dimensional, Phytoplankton, Microalgae, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Plastids, Plastid, Cellular microbiology, Trophic level, Biomass (ecology), Multidisciplinary, biology, Ecology, MESH: Energy Metabolism, fungi, MESH: Plastids, General Chemistry, biology.organism_classification, MESH: Light, Mitochondria, 030104 developmental biology, Diatom, MESH: Subcellular Fractions, Energy Metabolism, Subcellular Fractions, MESH: Phytoplankton, 010606 plant biology & botany
Abstract

Eukaryotic phytoplankton have a small global biomass but play major roles in primary production and climate. Despite improved understanding of phytoplankton diversity and evolution, we largely ignore the cellular bases of their environmental plasticity. By comparative 3D morphometric analysis across seven distant phytoplankton taxa, we observe constant volume occupancy by the main organelles and preserved volumetric ratios between plastids and mitochondria. We hypothesise that phytoplankton subcellular topology is modulated by energy-management constraints. Consistent with this, shifting the diatom Phaeodactylum from low to high light enhances photosynthesis and respiration, increases cell-volume occupancy by mitochondria and the plastid CO2-fixing pyrenoid, and boosts plastid-mitochondria contacts. Changes in organelle architectures and interactions also accompany Nannochloropsis acclimation to different trophic lifestyles, along with respiratory and photosynthetic responses. By revealing evolutionarily-conserved topologies of energy-managing organelles, and their role in phytoplankton acclimation, this work deciphers phytoplankton responses at subcellular scales., Nature Communications, 12 (1), ISSN:2041-1723

Published
2021

6. Exposure to Artificial Light at Night and the Consequences for Flora, Fauna, and Ecosystems

Author

Dina Attia, David Hicks, Christophe Martinsons, Francine Behar-Cohen, Françoise Viénot, Jack Falcón, Claude Gronfier, Alicia Torriglia, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), Centre de Recherche des Cordeliers (CRC (UMR_S_1138 / U1138)), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Université Paris Cité (UPCité), Direction de l'Evaluation des Risques (DER), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Centre de Recherche sur la Conservation (CRC ), Muséum national d'Histoire naturelle (MNHN)-Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center (CRNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre Scientifique et Technique du Bâtiment (CSTB), Institut des Neurosciences Cellulaires et Intégratives (INCI), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Université de Paris (UP), Centre de recherche en neurosciences de Lyon (CRNL), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), HAL-SU, Gestionnaire, and Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, photoreception, [SDV]Life Sciences [q-bio], Fauna, Foraging, Circadian clock, Light pollution, Review, Biology, 010603 evolutionary biology, 01 natural sciences, Natural (archaeology), lcsh:RC321-571, 03 medical and health sciences, Artificial-light, artificial-light-at-night, Ecosystem, [SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, anthropogenic impact, 0303 health sciences, Artificial light, Ecology, General Neuroscience, light-emitting-diodes, MESH: Light, Visual pigments, 13. Climate action, [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], ecosystems, biological clocks, Neuroscience
Abstract

International audience; The present review draws together wide-ranging studies performed over the last decades that catalogue the effects of artificial-light-at-night (ALAN) upon living species and their environment. We provide an overview of the tremendous variety of light-detection strategies which have evolved in living organisms - unicellular, plants and animals, covering chloroplasts (plants), and the plethora of ocular and extra-ocular organs (animals). We describe the visual pigments which permit photo-detection, paying attention to their spectral characteristics, which extend from the ultraviolet into infrared. We discuss how organisms use light information in a way crucial for their development, growth and survival: phototropism, phototaxis, photoperiodism, and synchronization of circadian clocks. These aspects are treated in depth, as their perturbation underlies much of the disruptive effects of ALAN. The review goes into detail on circadian networks in living organisms, since these fundamental features are of critical importance in regulating the interface between environment and body. Especially, hormonal synthesis and secretion are often under circadian and circannual control, hence perturbation of the clock will lead to hormonal imbalance. The review addresses how the ubiquitous introduction of light-emitting diode technology may exacerbate, or in some cases reduce, the generalized ever-increasing light pollution. Numerous examples are given of how widespread exposure to ALAN is perturbing many aspects of plant and animal behaviour and survival: foraging, orientation, migration, seasonal reproduction, colonization and more. We examine the potential problems at the level of individual species and populations and extend the debate to the consequences for ecosystems. We stress, through a few examples, the synergistic harmful effects resulting from the impacts of ALAN combined with other anthropogenic pressures, which often impact the neuroendocrine loops in vertebrates. The article concludes by debating how these anthropogenic changes could be mitigated by more reasonable use of available technology – for example by restricting illumination to more essential areas and hours, directing lighting to avoid wasteful radiation and selecting spectral emissions, to reduce impact on circadian clocks. We end by discussing how society should take into account the potentially major consequences that ALAN has on the natural world and the repercussions for ongoing human health and welfare.

Published
2020

7. Quelle est l'évidence montrant que la lumière nocture peux affecter la santé humaine?

Author

FrançoiseViénot, Arnaud Metlaine, Jack Falcón, Samuel Carré, Dina Attia, Christophe Martinsons, Francine Behar-Cohen, Leena Tähkämö, Alicia Torriglia, Olivier Enouf, Claude Gronfier, David Hicks, Institut des Neurosciences Cellulaires et Intégratives (INCI), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Direction de l'Evaluation des Risques (DER), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Sorbonne Université (SU), Centre de Recherche des Cordeliers (CRC (UMR_S_1138 / U1138)), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Centre Scientifique et Technique du Bâtiment (CSTB), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Muséum national d'Histoire naturelle (MNHN), Université Claude Bernard Lyon 1 - Faculté des sciences et technologies (UCBL FST), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Université Paris Descartes - Paris 5 (UPD5), and Aalto University

Subjects
MESH: Circadian Clocks, Light, Physiology, 020209 energy, MEDLINE, 02 engineering and technology, Affect (psychology), Light at night, 03 medical and health sciences, Cellular and Molecular Neuroscience, Human health, 0302 clinical medicine, Circadian Cellular Clock, Circadian Clocks, 0202 electrical engineering, electronic engineering, information engineering, Humans, Medicine, Lighting, Melatonin, business.industry, Sensory Systems, MESH: Light, Circadian Rhythm, Melatonin metabolism, Ophthalmology, Circadian activity, [SDE]Environmental Sciences, 030221 ophthalmology & optometry, business, Sleep
Abstract

This study was supported by the Agence Nationale de Sécurité Sanitaire de l’Alimentation, de l’Environnement et du Travail.; International audience; no abstract

Published
2020

8. Quelle est l'évidence montrant que la lumière nocture peux affecter la santé humaine?

Author

Hicks, David, Attia, Dina, Behar-Cohen, Francine, Carré, Samuel, Enouf, Olivier, Falcon, Jack, Gronfier, Claude, Martinsons, Christophe, Metlaine, Arnaud, Tahkamo, Leena, Torriglia, Alicia, Vienot, Françoise, Torriglia, Alicia, Institut des Neurosciences Cellulaires et Intégratives (INCI), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Direction de l'Evaluation des Risques (DER), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Sorbonne Université (SU), Centre de Recherche des Cordeliers (CRC (UMR_S_1138 / U1138)), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Centre Scientifique et Technique du Bâtiment (CSTB), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Muséum national d'Histoire naturelle (MNHN), Université Claude Bernard Lyon 1 - Faculté des sciences et technologies (UCBL FST), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Université Paris Descartes - Paris 5 (UPD5), Aalto University, French Agency for Food, Environmental and Occupational Health & Safety [Maisons-Alfort, France], École pratique des hautes études (EPHE)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), and Aalto University [Espoo, Finland]

Subjects
[SDE] Environmental Sciences, MESH: Circadian Clocks, Circadian Cellular Clock, Light, Physiology, Circadian activity, [SDE]Environmental Sciences, Sleep, ComputingMilieux_MISCELLANEOUS, MESH: Light, Melatonin
Abstract

This study was supported by the Agence Nationale de Sécurité Sanitaire de l’Alimentation, de l’Environnement et du Travail.; International audience; no abstract

Published
2020

9. Opto nongenetics inhibition of neuronal firing

Author

Nicola Kuczewski, Gwenaelle Laverne, Karima Ait Ouares, Marco Canepari, Corinne Beurrier, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Centre National de la Recherche Scientifique (CNRS), Institut de Neurobiologie de la Méditerranée [Aix-Marseille Université] (INMED - INSERM U1249), Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU), Poulain, Sébastien, Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center (CRNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), and Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
Male, Opsin, Cerebellum, Light, hippocampus, [SDV]Life Sciences [q-bio], [SDV.NEU.NB]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology, striatum, MESH: Neurons, Action Potentials, Hippocampus, Striatum, Hippocampal formation, light stimulation, MESH: Optogenetics, 0302 clinical medicine, MESH: Animals, ComputingMilieux_MISCELLANEOUS, MESH: Action Potentials, Neurons, 0303 health sciences, Chemistry, General Neuroscience, Brain, MESH: Neural Inhibition, [SDV] Life Sciences [q-bio], medicine.anatomical_structure, olfactory bulb, [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], MESH: Olfactory Bulb, mice, cerebellum, MESH: CA1 Region, Hippocampal, Optogenetics, Medium spiny neuron, MESH: Brain, 03 medical and health sciences, MESH: Mice, Inbred C57BL, medicine, Animals, optogenetics, CA1 Region, Hippocampal, 030304 developmental biology, [SDV.NEU.NB] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology, Neural Inhibition, brain slices, MESH: Cerebellum, MESH: Light, MESH: Male, Olfactory bulb, Mice, Inbred C57BL, Neostriatum, MESH: Neostriatum, nervous system, Neuroscience, 030217 neurology & neurosurgery
Abstract

International audience; Optogenetics is based on the selective expression of exogenous opsins by neurons allowing experimental control of their electrical activity using visible light. The interpretation of the results of optogenetic experiments is based on the assumption that light stimulation selectively acts on those neurons expressing the exogenous opsins without perturbing the activity of naive ones. Here, we report that light stimulation, of wavelengths and power in the range of those normally used in optogenetic experiments, consistently reduces the firing activity of naive Mitral Cells (MCs) and Tufted Neurons in the olfactory bulb as well as in Medium Spiny Neurons (MSNs) in the striatum. No such effect was observed for cerebellar Purkinje and hippocampal CA1 neurons. The effects on MC firing appear to be mainly due to a light-induced increase in tissue temperature, between 0.1 and 0.4°C, associated with the generation of a hyperpolarizing current and a modification of action potential (AP) shape. Therefore, light in the visible range can affect neuronal physiology in a cell-specific manner. Beside the implications for optogenetic studies, our results pave the way to investigating the use of visible light for therapeutic purposes in pathologies associated with neuronal hyperexcitability.

Published
2018

10. Sensitive bioluminescence imaging of fungal dissemination to the brain in mouse models of cryptococcosis

Author

Matthias Brock, Liesbeth Vanherp, Amy Hillen, Guilhem Janbon, Katrien Lagrou, Alexandra Ristani, Jennifer Poelmans, Uwe Himmelreich, Greetje Vande Velde, Biomedical MRI [Leuven], Department of Imaging and Pathology [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven)-Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), core facility Molecular Small Animal Imaging Center (Leuven) (MoSAIC), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Université Catholique de Louvain = Catholic University of Louvain (UCL), Laboratory of Clinical Bacteriology and Mycology [Leuven], Department of Microbiology, Immunology and Transplantation [Leuven], Biologie des ARN des Pathogènes fongiques - RNA Biology of Fungal Pathogens, Institut Pasteur [Paris], School of Life Sciences, University of Nottingham, UK (UON), This work was funded by the European Commission ERA-NET project ‘CryptoView’ (third call of the FP7 program Infect-ERA), the Research Foundation-Flanders (FWO, Fonds Wetenschappelijk Onderzoek, 1506114N) and KU Leuven [PF 10/017 (IMIR), CREA/14/015]. L.V. is a PhD fellow strategic basic research at the FWO (151313). J.P. received a PhD grant for strategic basic research from the Agency for Innovation by Science and Technology (IWT, 141230). G.V.V. received a postdoctoral fellowship from the FWO (12N7615N)., The authors thank Kristof Govaerts for his assistance with the MRI quantification, Dr Lore Pollaris for guidance with the endotracheal model and all partners involved in the ERA-NET project ‘CryptoView’ for the fruitful discussions., European Project: 321529,EC:FP7:HEALTH,FP7-ERANET-2012-RTD,INFECT-ERA(2013), and Institut Pasteur [Paris] (IP)

Subjects
0301 basic medicine, Fungal infection, MESH: Trachea / diagnostic imaging, Pathology, Light, MESH: Trachea / pathology, Cryptococcus, Medicine (miscellaneous), lcsh:Medicine, Disease, MESH: X-Ray Microtomography, MESH: Cryptococcosis / diagnostic imaging, Imaging, MESH: Magnetic Resonance Imaging, 0302 clinical medicine, Immunology and Microbiology (miscellaneous), Non-invasive imaging, MESH: Brain / microbiology, MESH: Trachea / microbiology, MESH: Animals, MESH: Administration, Intranasal, Pathogen, [SDV.MP.MYC]Life Sciences [q-bio]/Microbiology and Parasitology/Mycology, Blood-brain barrier, Mice, Inbred BALB C, medicine.diagnostic_test, biology, Brain, Cryptococcosis, Magnetic Resonance Imaging, 3. Good health, Trachea, medicine.anatomical_structure, Disease Progression, Female, MESH: Disease Progression, Bioluminescence, lcsh:RB1-214, medicine.medical_specialty, Neuroscience (miscellaneous), MESH: Mice, Inbred BALB C, Blood–brain barrier, General Biochemistry, Genetics and Molecular Biology, Mouse model, 03 medical and health sciences, medicine, lcsh:Pathology, Bioluminescence imaging, Animals, Resource Article, MESH: Brain / diagnostic imaging, Administration, Intranasal, Cryptococcus neoformans, lcsh:R, Magnetic resonance imaging, X-Ray Microtomography, biology.organism_classification, medicine.disease, MESH: Light, MESH: Luminescent Measurements, Disease Models, Animal, 030104 developmental biology, Luminescent Measurements, MESH: Brain / pathology, MESH: Cryptococcosis / pathology, Pulmonary disease, MESH: Disease Models, Animal, MESH: Female, 030217 neurology & neurosurgery, MESH: Cryptococcosis / microbiology
Abstract

Cryptococcus neoformans is a leading cause of fungal brain infection, but the mechanism of dissemination and dynamics of cerebral infection following pulmonary disease are poorly understood. To address these questions, non-invasive techniques that can study the dynamic processes of disease development and progression in living animal models or patients are required. As such, bioluminescence imaging (BLI) has emerged as a powerful tool to evaluate the spatial and temporal distribution of infection in living animals. We aimed to study the time profile of the dissemination of cryptococcosis from the lung to the brain in murine models by engineering the first bioluminescent C. neoformans KN99α strain, expressing a sequence-optimized red-shifted luciferase. The high pathogen specificity and sensitivity of BLI was complemented by the three-dimensional anatomical information from micro-computed tomography (μCT) of the lung and magnetic resonance imaging (MRI) of the brain. These non-invasive imaging techniques provided longitudinal readouts on the spatial and temporal distribution of infection following intravenous, intranasal or endotracheal routes of inoculation. Furthermore, the imaging results correlated strongly with the fungal load in the respective organs. By obtaining dynamic and quantitative information about the extent and timing of brain infections for individual animals, we found that dissemination to the brain after primary infection of the lung is likely a late-stage event with a timeframe that is variable between animals. This novel tool in Cryptococcus research can aid the identification of host and pathogen factors involved in this process, and supports development of novel preventive or therapeutic approaches., Summary: A novel combination of bioluminescence and anatomical imaging non-invasively identified the timeframe and extent of Cryptococcus neoformans dissemination to the brain in animal models of systemic and pulmonary fungal infection.

Published
2019

11. Regulation of Orange Carotenoid Protein Activity in Cyanobacterial Photoprotection

Author

Céline Bourcier de Carbon, Diana Kirilovsky, Léa Comolet, Adjélé Wilson, Adrien Thurotte, Fugui Xiao, Rocío López-Igual, Institut de Biologie Intégrative de la Cellule ( I2BC ), Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Sud - Paris 11 ( UP11 ), Laboratory of Biophysics, Wageningen University and Research Centre [Wageningen] ( WUR ), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Wageningen University and Research [Wageningen] (WUR)

Subjects
Models, Molecular, 0106 biological sciences, Cyanobacteria, MESH : Escherichia coli, Light, Physiology, [SDV]Life Sciences [q-bio], MESH : Synechocystis, MESH : Models, Biological, Plant Science, Orange (colour), MESH: Synechocystis, 01 natural sciences, polycyclic compounds, Phycobilisomes, MESH : Bacterial Proteins, MESH : Light, MESH: Bacterial Proteins, Carotenoid, chemistry.chemical_classification, 0303 health sciences, MESH: Escherichia coli, Synechocystis, food and beverages, MESH : Protein Binding, Articles, Fluorescence, Biofysica, Biochemistry, MESH : Mutation, MESH: Models, Molecular, Protein Binding, MESH : Fluorescence, MESH: Mutation, MESH : Models, Molecular, Biophysics, macromolecular substances, Biology, Models, Biological, 03 medical and health sciences, Bacterial Proteins, Escherichia coli, Genetics, Life Science, MESH: Protein Binding, MESH: Phycobilisomes, 030304 developmental biology, [ SDV ] Life Sciences [q-bio], Orange carotenoid protein, organic chemicals, MESH: Fluorescence, MESH: Models, Biological, biology.organism_classification, MESH: Light, MESH : Phycobilisomes, chemistry, Photoprotection, Mutation, bacteria, Phycobilisome, Excess energy, 010606 plant biology & botany
Abstract

International audience; Plants, algae, and cyanobacteria have developed mechanisms to decrease the energy arriving at reaction centers to protect themselves from high irradiance. In cyanobacteria, the photoactive Orange Carotenoid Protein (OCP) and the Fluorescence Recovery Protein are essential elements in this mechanism. Absorption of strong blue-green light by the OCP induces carotenoid and protein conformational changes converting the orange (inactive) OCP into a red (active) OCP. Only the red orange carotenoid protein (OCP(r)) is able to bind to phycobilisomes, the cyanobacterial antenna, and to quench excess energy. In this work, we have constructed and characterized several OCP mutants and focused on the role of the OCP N-terminal arm in photoactivation and excitation energy dissipation. The N-terminal arm largely stabilizes the closed orange OCP structure by interacting with its C-terminal domain. This avoids photoactivation at low irradiance. In addition, it slows the OCP detachment from phycobilisomes by hindering fluorescence recovery protein interaction with bound OCP(r). This maintains thermal dissipation of excess energy for a longer time. Pro-22, at the beginning of the N-terminal arm, has a key role in the correct positioning of the arm in OCP(r), enabling strong OCP binding to phycobilisomes, but is not essential for photoactivation. Our results also show that the opening of the OCP during photoactivation is caused by the movement of the C-terminal domain with respect to the N-terminal domain and the N-terminal arm.

Published
2015

12. Toxoplasma gondii: Biochemical and biophysical characterization of recombinant soluble dense granule proteins GRA2 and GRA6

Author

Guy Schoehn, Jean Gagnon, Laetitia Travier, Grégory Effantin, Corinne Mercier, Graciane Petre, Amina Bittame, Winfried Weissenhorn, Pauline Ruffiot, Marie-France Cesbron-Delauw, Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble] (LAPM), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Institut de biologie structurale (IBS - UMR 5075 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-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)-Centre National de la Recherche Scientifique (CNRS), Thomas, Frank, Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Protein Folding, Circular dichroism, Light, [SDV.BBM.BS] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], MESH: Protein Folding, Population, Protozoan Proteins, Biophysics, MESH: Protein Structure, Secondary, Antigens, Protozoan, Biology, Biochemistry, Protein Structure, Secondary, MESH: Circular Dichroism, law.invention, MESH: Recombinant Proteins, Microscopy, Electron, Transmission, law, parasitic diseases, Scattering, Radiation, MESH: Scattering, Radiation, education, MESH: Protozoan Proteins, Molecular Biology, Protein secondary structure, education.field_of_study, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Circular Dichroism, Intracellular parasite, Toxoplasma gondii, Cell Biology, biology.organism_classification, Recombinant Proteins, MESH: Light, Cell biology, MESH: Solubility, Solubility, MESH: Microscopy, Electron, Transmission, Recombinant DNA, Dense granule, Biogenesis, MESH: Antigens, Protozoan
Abstract

International audience; The most prominent structural feature of the parasitophorous vacuole (PV) in which the intracellular parasite Toxoplasma gondii proliferates is a membranous nanotubular network (MNN), which interconnects the parasites and the PV membrane. The MNN function remains unclear. The GRA2 and GRA6 proteins secreted from the parasite dense granules into the PV have been implicated in the MNN biogenesis. Amphipathic alpha-helices (AAHs) predicted in GRA2 and an alpha-helical hydrophobic domain predicted in GRA6 have been proposed to be responsible for their membrane association, thereby potentially molding the MMN in its structure. Here we report an analysis of the recombinant proteins (expressed in detergent-free conditions) by circular dichroism, which showed that full length GRA2 displays an alpha-helical secondary structure while recombinant GRA6 and GRA2 truncated of its AAHs are mainly random coiled. Dynamic light scattering and transmission electron microscopy showed that recombinant GRA6 and truncated GRA2 constitute a homogenous population of small particles (6-8 nm in diameter) while recombinant GRA2 corresponds to 2 populations of particles (∼8-15 nm and up to 40 nm in diameter, respectively). The unusual properties of GRA2 due to its AAHs are discussed.

Published
2015

13. Secretory Vesicle Clustering in Fungal Filamentous Cells Does Not Require Directional Growth

Author

Agnese Seminara, Charles Puerner, Martine Bassilana, Robert A. Arkowitz, Patrícia M. Silva, Institut de Biologie Valrose (IBV), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Nice (INPHYNI), Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), ANR-15-IDEX-0001,UCA JEDI,Idex UCA JEDI (2016), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), ANR-15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015), Arkowitz, Robert, Idex UCA JEDI - - UCA JEDI2015 - ANR-15-IDEX-0001 - IDEX - VALID, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), and COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)

Subjects
0301 basic medicine, Light, MESH: Secretory Vesicles, [SDV]Life Sciences [q-bio], GTPase, CDC42, MESH: Optogenetics, 0302 clinical medicine, Models, Candida albicans, morphology, Cell polarity, polarity, Cdc42, cdc42 GTP-Binding Protein, lcsh:QH301-705.5, [SDV.BDD]Life Sciences [q-bio]/Development Biology, [SDV.MP.MYC]Life Sciences [q-bio]/Microbiology and Parasitology/Mycology, Budding, MESH: Guanosine Triphosphate, Chemistry, Secretory Vesicle, Endocytosis, Cell biology, Actin Cytoskeleton, MESH: Endocytosis, MESH: Fungal Proteins, Guanosine Triphosphate, Protein subunit, Exocyst, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, membrane traffic, fungi, optogenetics, Cell Membrane, Fungal Proteins, Models, Biological, Optogenetics, Secretory Vesicles, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, [SDV.BDD] Life Sciences [q-bio]/Development Biology, [SDV.BC] Life Sciences [q-bio]/Cellular Biology, MESH: cdc42 GTP-Binding Protein, Polarity (international relations), MESH: Candida albicans, MESH: Models, Biological, Biological, [SDV.MP.MYC] Life Sciences [q-bio]/Microbiology and Parasitology/Mycology, MESH: Light, 030104 developmental biology, lcsh:Biology (General), MESH: Actin Cytoskeleton, 030217 neurology & neurosurgery, MESH: Cell Membrane
Abstract

Summary: During symmetry breaking, the highly conserved Rho GTPase Cdc42 becomes stabilized at a defined site via an amplification process. However, little is known about how a new polarity site is established in an already asymmetric cell—a critical process in a changing environment. The human fungal pathogen Candida albicans switches from budding to filamentous growth in response to external cues, a transition controlled by Cdc42. Here, we have used optogenetic manipulation of cell polarity to reset growth in asymmetric filamentous C. albicans cells. We show that increasing the level of active Cdc42 on the plasma membrane results in disruption of the exocyst subunit Sec3 localization and a striking de novo clustering of secretory vesicles. This new cluster of secretory vesicles is highly dynamic, moving by hops and jumps, until a new growth site is established. Our results reveal that secretory vesicle clustering can occur in the absence of directional growth. : Silva et al. use light-dependent plasma membrane recruitment of active Cdc42 to reset polarity in asymmetric filamentous fungal cells. This transient increase in plasma membrane active Cdc42 disrupted membrane traffic and resulted in the formation of a striking de novo secretory vesicle cluster, in the absence of directional growth. Keywords: polarity, optogenetics, Cdc42, membrane traffic, morphology, fungi

Published
2019

14. A simple layer-stacking technique to generate biomolecular and mechanical gradients in photocrosslinkable hydrogels

Author

Yuting Niu, Somayeh Zanganeh, Héloïse Mary, Jeremy J. Mao, Shu-Kai Hu, Ali Khademhosseini, Goro Choi, Hyojin Ko, Samad Ahadian, Yunzhi Yang, Kasinan Suthiwanich, Kirsten Fetah, Center for Minimally Invasive Therapeutics [Los Angeles] (C-MIT), University of California [Los Angeles] (UCLA), University of California-University of California, Henry Samueli School of Engineering and Applied Sciences [Los Angeles], Tokyo Institute of Technology [Tokyo] (TITECH), Pôle Odontologie [CHU Reims], Centre Hospitalier Universitaire de Reims (CHU Reims), Plateforme technologique Biomatériaux et Microfluidique - Biomaterials and Microfluidics technologic Platform, Institut Pasteur [Paris], National Taiwan University [Taiwan] (NTU), Stanford University, Center for Craniofacial Regeneration [New York], Columbia University [New York], University of California (UC)-University of California (UC), and Institut Pasteur [Paris] (IP)

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, Light, Polymers, Swine, 02 engineering and technology, Biochemistry, Gelatin, Mice, chemistry.chemical_compound, Tissue engineering, Fluorescence microscope, MESH: Animals, MESH: Swine, [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment, Hydrogels, Serum Albumin, Bovine, General Medicine, 021001 nanoscience & nanotechnology, MESH: Methacrylates, MESH: Polymers, Cross-Linking Reagents, Self-healing hydrogels, Methacrylates, 0210 nano-technology, Layer (electronics), Biotechnology, MESH: Hydrogels, Materials science, food.ingredient, Ultraviolet Rays, MESH: Cross-Linking Reagents, 0206 medical engineering, Biomedical Engineering, Stacking, Bioengineering, macromolecular substances, complex mixtures, Article, Biomaterials, food, MESH: Mechanical Phenomena, Animals, Humans, MESH: Mice, Mechanical Phenomena, MESH: Humans, Layer by layer, technology, industry, and agriculture, 020601 biomedical engineering, MESH: Light, Chemical engineering, chemistry, NIH 3T3 Cells, MESH: Ultraviolet Rays, Ethylene glycol, MESH: Serum Albumin, Bovine, MESH: NIH 3T3 Cells
Abstract

International audience; Physicochemical and biological gradients are desirable features for hydrogels to enhance their relevance to biological environments for three-dimensional (3D) cell culture. Therefore, simple and efficient techniques to generate chemical, physical and biological gradients within hydrogels are highly desirable. This work demonstrates a technique to generate biomolecular and mechanical gradients in photocrosslinkable hydrogels by stacking and crosslinking prehydrogel solution in a layer by layer manner. Partial crosslinking of the hydrogel allows mixing of prehydrogel solution with the previous hydrogel layer, which makes a smooth gradient profile, rather than discrete layers. This technique enables the generation of concentration gradients of bovine serum albumin in both gelatin methacryloyl (GelMA) and poly(ethylene glycol) diacrylate hydrogels, as well as mechanical gradients across a hydrogel containing varying gel concentrations. Fluorescence microscopy, mechanical testing, and scanning electron microscopy show that the gradient profiles can be controlled by changing both the volume and concentration of each layer as well as intensity of UV exposure. GelMA hydrogel gradients with different Young's moduli were successfully used to culture human fibroblasts. The fibroblasts migrated along the gradient axis and showed different morphologies. In general, the proposed technique provides a rapid and simple approach to design and fabricate 3D hydrogel gradients for in vitro biological studies and potentially for in vivo tissue engineering applications.

Published
2019

15. A blue-light photoreceptor mediates the feedback regulation of photosynthesis

Author

Leonardo Magneschi, Shinichiro Maruyama, Jun Minagawa, Maria Mittag, Andre Greiner, Peter Hegemann, Tilman Kottke, Serena Flori, Loic Cusant, Dimitris Petroutsos, Ryutaro Tokutsu, Giovanni Finazzi, Physiologie cellulaire et végétale (LPCV), 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), 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), Division of Environmental Photobiology, National Institute for Basic Biology [Okazaki], Tohoku University [Sendai], Humboldt State University (HSU), Institute for Plant Biochemistry and Biotechnology, Westfälische Wilhelms-Universität Münster (WWU), Physical and Biophysical Chemistry, Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität Jena, Marie Curie Initial Training Network Accliphot (FP7-PEOPLE-2012-ITN), CNRS Défi (ENRS 2013), CEA Bioénergies program, HFSP (HFSP0052), NIBB Cooperative Research Program for the Okazaki Large Spectrograph, JSPS KAKENHI (JP15H05599, JP26251033 and JP16H06553), NEDO (P07015), MEXT (through the Network of Centres of Carbon Dioxide Resource Studies in Plants, German Research Foundation, DFG, grants FOR1261, ANR-12-BIME-0005,DiaDomOil,Domestication des diatomées pour la production de biocarburants(2012), ANR-10- LABX-49-01,Labex GRAL,Labex GRAL, 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), Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], ANR-10-LABX-0049,GRAL,Grenoble Alliance for Integrated Structural Cell Biology(2010), and 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)

Subjects
0106 biological sciences, 0301 basic medicine, MESH: Chlamydomonas reinhardtii, Phototropins, Light Signal Transduction, Phototropin, MESH: Light-Harvesting Protein Complexes, Light, Algae, Cell Survival, MESH: Feedback, Physiological, Acclimatization, Light-Harvesting Protein Complexes, Color, Phot, MESH: Acclimatization, Biology, Photochemistry, 01 natural sciences, 03 medical and health sciences, Cryptochrome, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Photosynthesis, MESH: Protein Kinases, MESH: Photosynthesis, MESH: Color, Feedback, Physiological, Multidisciplinary, Photoreceptor, MESH: Phototropins, Phytochrome, Photoprotection, Non-photochemical quenching, MESH: Photosystem II Protein Complex, Photosystem II Protein Complex, MESH: Light Signal Transduction, MESH: Light, Light intensity, 030104 developmental biology, MESH: Cell Survival, Light acclimation, Biophysics, Energy source, Protein Kinases, Chlamydomonas reinhardtii, 010606 plant biology & botany
Abstract

International audience; In plants and algae, light serves both as the energy source for photosynthesis and a biological signal that triggers cellular responses via specific sensory photoreceptors. Red light is perceived by bilin-containing phytochromes and blue light by the flavin-containing cryptochromes and/or phototropins (PHOTs), the latter containing two photosensory light, oxygen, or voltage (LOV) domains. Photoperception spans several orders of light intensity, ranging from far below the threshold for photosynthesis to values beyond the capacity of photosynthetic CO2 assimilation. Excess light may cause oxidative damage and cell death, processes prevented by enhanced thermal dissipation via high-energy quenching (qE), a key photoprotective response. Here we show the existence of a molecular link between photoreception, photosynthesis, and photoprotection in the green alga Chlamydomonas reinhardtii. We show that PHOT controls qE by inducing the expression of the qE effector protein LHCSR3 (light-harvesting complex stress-related protein 3) in high light intensities. This control requires blue-light perception by LOV domains on PHOT, LHCSR3 induction through PHOT kinase, and light dissipation in photosystem II via LHCSR3. Mutants deficient in the PHOT gene display severely reduced fitness under excessive light conditions, indicating that the sensing, utilization, and dissipation of light is a concerted process that plays a vital role in microalgal acclimation to environments of variable light intensities.

Published
2016

16. Targeting Channelrhodopsin-2 to ON-bipolar Cells With Vitreally Administered AAV Restores ON and OFF Visual Responses in Blind Mice

Author

Serge Picaud, José-Alain Sahel, Antoine Chaffiol, Jens Duebel, Deniz Dalkara, Ernst Bamberg, Emilie Mace, Romain Caplette, Abhishek Sengupta, Olivier Marre, Melissa Desrosiers, Peggy Barbe, Marre, Olivier, Institut de la Vision, Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Biophysik - Max Planck Institute of Biophysics (MPIBP), Max-Planck-Gesellschaft, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts (CHNO), and Fondation Ophtalmologique Adolphe de Rothschild [Paris]

Subjects
Retinal Ganglion Cells, Retinal degeneration, Light, genetic structures, [SDV]Life Sciences [q-bio], Gene Expression, Channelrhodopsin, MESH: Dependovirus, Blindness, Photoreceptor cell, Mice, chemistry.chemical_compound, MESH: Blindness, MESH: Retinal Bipolar Cells, MESH: Genetic Vectors, Drug Discovery, MESH: Behavior, Animal, MESH: Animals, Promoter Regions, Genetic, Behavior, Animal, Retinal Degeneration, Gene Transfer Techniques, Anatomy, Dependovirus, [SDV] Life Sciences [q-bio], medicine.anatomical_structure, Intravitreal Injections, Visual Perception, Molecular Medicine, MESH: Genetic Engineering, Original Article, Female, Genetic Engineering, Retinal Dystrophies, MESH: Channelrhodopsins, Retinal Bipolar Cells, MESH: Gene Expression, MESH: Retinal Degeneration, MESH: Mice, Transgenic, Genetic Vectors, Mice, Transgenic, MESH: Gene Transfer Techniques, Optogenetics, Gene delivery, Biology, MESH: Intravitreal Injections, Channelrhodopsins, MESH: Mice, Inbred C57BL, MESH: Promoter Regions, Genetic, Genetics, medicine, Animals, Molecular Biology, MESH: Mice, Pharmacology, MESH: Genetic Therapy, Retina, MESH: Visual Perception, MESH: Vitreous Body, Retinal, MESH: Retinal Ganglion Cells, Genetic Therapy, medicine.disease, eye diseases, MESH: Light, Mice, Inbred C57BL, Vitreous Body, chemistry, sense organs, Neuroscience, MESH: Female
Abstract

International audience; Most inherited retinal dystrophies display progressive photoreceptor cell degeneration leading to severe visual impairment. Optogenetic reactivation of retinal neurons mediated by adeno-associated virus (AAV) gene therapy has the potential to restore vision regardless of patient-specific mutations. The challenge for clinical translatability is to restore a vision as close to natural vision as possible, while using a surgically safe delivery route for the fragile degenerated retina. To preserve the visual processing of the inner retina, we targeted ON bipolar cells, which are still present at late stages of disease. For safe gene delivery, we used a recently engineered AAV variant that can transduce the bipolar cells after injection into the eye's easily accessible vitreous humor. We show that AAV encoding channelrhodopsin under the ON bipolar cell-specific promoter mediates long-term gene delivery restricted to ON-bipolar cells after intravitreal administration. Channelrhodopsin expression in ON bipolar cells leads to restoration of ON and OFF responses at the retinal and cortical levels. Moreover, light-induced locomotory behavior is restored in treated blind mice. Our results support the clinical relevance of a minimally invasive AAV-mediated optogenetic therapy for visual restoration.

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results