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7 results on '"MESH: Phosphorus"'

1. Root developmental adaptation to phosphate starvation: better safe than sorry

Author

Laurent Nussaume, Benjamin Péret, Thierry Desnos, Mathilde Clément, Centre for Plant Integrative Biology [Nothingham] (CPIB), University of Nottingham, UK (UON), Biologie cellulaire et moléculaire des plantes et des bactéries (BCMPB), Université de la Méditerranée - Aix-Marseille 2-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Plant Environmental Physiology and Stress Signaling (PEPSS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de la Méditerranée - Aix-Marseille 2, Signalisation de l'Adaptation des Végétaux à l'Environnement (SAVE), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Arabidopsis, MESH: Plant Roots, chemistry.chemical_element, MESH: Arabidopsis Proteins, Plant Science, MESH: Fertilizers, Root hair, Plant Roots, 01 natural sciences, Phosphates, Phosphorus metabolism, 03 medical and health sciences, chemistry.chemical_compound, Gene Expression Regulation, Plant, Botany, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Arabidopsis thaliana, MESH: Arabidopsis, Phosphorus deficiency, MESH: Gene Expression Regulation, Plant, Fertilizers, MESH: Phosphorus, Lateral root formation, 030304 developmental biology, 2. Zero hunger, 0303 health sciences, biology, Arabidopsis Proteins, Phosphorus, 15. Life on land, Phosphate, biology.organism_classification, Adaptation, Physiological, MESH: Adaptation, Physiological, chemistry, Agronomy, MESH: Phosphates, 010606 plant biology & botany
Abstract

International audience; Phosphorus is a crucial component of major organic molecules such as nucleic acids, ATP and membrane phospholipids. It is present in soils in the form of inorganic phosphate (Pi), which has low availability and poor mobility. To cope with Pi limitations, plants have evolved complex adaptive responses that include morphological and physiological modifications. This review describes how the model plant Arabidopsis thaliana adapts its root system architecture to phosphate deficiency through inhibition of primary root growth, increase in lateral root formation and growth and production of root hairs, which all promote topsoil foraging. A better understanding of plant adaptation to low phosphate will open the way to increased phosphorus use efficiency by crops. Such an improvement is needed in order to adjust how we manage limited phosphorus stocks and to reduce the disastrous environmental effects of phosphate fertilizers overuse.

Published
2011

2. X-ray spectroscopy and X-ray diffraction at wavelengths near theK-absorption edge of phosphorus

Author

Corinne Mas, Gérard Brandolin, J. Vicat, Richard Kahn, Heinrich Stuhrmann, Hugues Nury, Valérie Biou, Eva Pebay-Peyroula, Jean Marie Bois, Lionel Nauton, Peter Bösecke, Laboratoire d'enzymologie et biochimie structurales (LEBS), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mathématiques de Reims (LMR), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Biochimie et biophysique des systèmes intégrés (BBSI), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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), Université Joseph Fourier - Grenoble 1 (UJF)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-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
Halobacterium, Diffraction, Nuclear and High Energy Physics, Absorption spectroscopy, Protein Conformation, Carbon-Oxygen Lyases, Neutron diffraction, Molecular Conformation, Analytical chemistry, MESH: Equipment Failure Analysis, 01 natural sciences, MESH: Carbon-Oxygen Lyases, Crystal, 03 medical and health sciences, MESH: Protein Conformation, Purple Membrane, X-Ray Diffraction, 0103 physical sciences, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], MESH: Phosphorus, Instrumentation, 030304 developmental biology, 010302 applied physics, MESH: Molecular Conformation, 0303 health sciences, X-ray spectroscopy, Radiation, Chemistry, MESH: X-Ray Diffraction, Spectrometry, X-Ray Emission, MESH: Spectrometry, X-Ray Emission, Phosphorus, Equipment Design, MESH: Purple Membrane, Equipment Failure Analysis, Wavelength, Crystallography, Absorption edge, X-ray crystallography, MESH: Halobacterium, MESH: Mitochondrial ADP, ATP Translocases, Mitochondrial ADP, ATP Translocases, MESH: Equipment Design
Abstract

International audience; Phosphorus is an abundant element in living organisms. It is traceable by its X-ray absorption spectrum which shows a strong white line at its K-edge, comparable with that observed for the L(III) edges of rare earth ions. With purple membrane, the variation of the imaginary part of the anomalous dispersion of phosphorus is found to be close to 20 anomalous electron units. Anomalous diffraction experiments at wavelengths near the K-absorption edge of phosphorus confirm this result. The spatial distribution of lipids derived from anomalous diffraction agrees with earlier results from neutron diffraction. Test experiments on single crystals of the carrier protein using 5.76 A photons gave a first low-resolution diffraction pattern. Various techniques of crystal mounting were attempted. In addition, fluorescence measurements on a solution of threonine synthase appear to hint at a change of the phosphate environment of the cofactor upon activator binding.

Published
2005

3. Determination of and Coupling Constants in 13C-Labeled Nucleic Acids Using Constant-Time HMQC

Author

Serge Bouaziz, Abdelali Kettani, Weidong Hu, Eugene Skripkin, Unité de Pharmacologie Chimique et Génétique (UPCG - UMR_S 640/UMR 8151), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris Descartes - Paris 5 (UPD5)-Institut des sciences du Médicament -Toxicologie - Chimie - Environnement (IFR71), Institut National de la Santé et de la Recherche Médicale (INSERM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Institut de Chimie du CNRS (INC), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut des sciences du Médicament -Toxicologie - Chimie - Environnement (IFR71), Institut de Recherche pour le Développement (IRD)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Bouaziz, Serge

Subjects
Coupling constant, 0303 health sciences, Nuclear and High Energy Physics, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], [SDV.BBM.BS] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], MESH: Magnetic Resonance Spectroscopy, Chemistry, MESH: DNA, Biophysics, Analytical chemistry, MESH: Carbon Isotopes, Torsion (mechanics), 010402 general chemistry, Condensed Matter Physics, Intensity ratio, 01 natural sciences, Biochemistry, 0104 chemical sciences, 03 medical and health sciences, Nucleic acid, MESH: Protons, MESH: Phosphorus, 030304 developmental biology
Abstract

International audience; A novel 1H-13C correlated two-dimensional experiment, CT-HMQC-J, for the measurement of three-bond proton-phosphorus coupling constants in 13C-labeled DNA is described. The experiment is based on the intensity difference of 1H-13C cross peaks in the presence and absence of the proton-phosphorus coupling interaction during the constant-time period in HMQC experiment. The 3J(H, P) coupling constants can be easily extracted from the intensity ratios of the two experiments. The method has been applied to a uniformly 13C, 15N-labeled d(GGAGGAT) 7-mer DNA sample. The proton-phosphorus coupling constants determined from CT-HMQC-J, together with the other three-bond coupling constants, are used to determine beta and epsilon torsion angles. The introduction of beta and epsilon restraints has improved the convergence as well as the quality of d(GGAGGAT) structure.

Published
1999

4. Biomedical applications of the ESRF synchrotron-based microspectroscopy platform

Author

Jean Susini, Marine Cotte, Sylvain Bohic, Barbara Fayard, Markus Kuehbacher, Gema Martínez-Criado, Rémi Tucoulou, Peter Cloetens, Murielle Salomé, INSERM U836, équipe 6, Rayonnement synchrotron et recherche médicale, European Synchrotron Radiation Facility (ESRF)-Grenoble Institut des Neurosciences (GIN), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Santé et de la Recherche Médicale (INSERM), European Synchrotron Radiation Facility (ESRF), Centre de recherche et de restauration des musées de France (C2RMF), Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture et de la Communication (MCC), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Department of Molecular Trace Element Research in the Life Sciences, Hahn-Meitner-Institut, National Health and Medical Research Council of Australia, Schizophrenia Research Institute, National Institute of Alcohol Abuse and Alcoholism (NIH (NIAAA) R24AA012725), Neuroscience Research Australia, University of New South Wales, National Health, Medical Research Council of Australia, Ministère de la Culture et de la Communication (MCC)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), and Serduc, Raphael

Subjects
Chemical imaging, Male, BALB 3T3 Cells, 02 engineering and technology, 01 natural sciences, PC12 Cells, law.invention, MESH: Hepatocytes, Mice, MESH: Melanins, Structural Biology, law, Microscopy, Spectroscopy, Fourier Transform Infrared, MESH: Dopaminergic Neurons, MESH: Animals, Metal ions, MESH: Phosphorus, MESH: Spermatozoa, MESH: BALB 3T3 Cells, Phosphorus, 021001 nanoscience & nanotechnology, Spermatozoa, Synchrotron, On cells, X ray microprobe, Metals, Microspectrophotometry, X-ray spectroscopy, MESH: Synchrotrons, Nanomedicine, [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], France, MESH: Microspectrophotometry, 0210 nano-technology, X-ray microprobe, Materials science, MESH: Rats, Biomedical Technology, MESH: Manganese, Nanotechnology, MESH: Spectroscopy, Fourier Transform Infrared, MESH: X-Rays, Animals, Humans, MESH: PC12 Cells, [SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], MESH: Mice, Melanins, Manganese, MESH: Metals, MESH: Humans, Dopaminergic Neurons, X-Rays, 010401 analytical chemistry, MESH: Male, 0104 chemical sciences, Rats, MESH: France, Chemical sensitivity, MESH: Potassium, Hepatocytes, Potassium, Cell, MESH: Biomedical Technology, Synchrotrons
Abstract

International audience; Very little is known about the sub-cellular distribution of metal ions in cells. Some metals such as zinc, copper and iron are essential and play an important role in the cell metabolism. Dysfunctions in this delicate housekeeping may be at the origin of major diseases. There is also a prevalent use of metals in a wide range of diagnostic agents and drugs for the diagnosis or treatment of a variety of disorders. This is becoming more and more of a concern in the field of nanomedicine with the increasing development and use of nanoparticles, which are suspected of causing adverse effects on cells and organ tissues. Synchrotron-based X-ray and Fourier-transformed infrared microspectroscopies are developing into well-suited sub-micrometer analytical tools for addressing new problems when studying the role of metals in biology. As a complementary tool to optical and electron microscopes, developments and studies have demonstrated the unique capabilities of multi-keV microscopy: namely, an ultra-low detection limit, large penetration depth, chemical sensitivity and three-dimensional imaging capabilities. More recently, the capabilities have been extended towards sub-100nm lateral resolutions, thus enabling sub-cellular chemical imaging. Possibilities offered by these techniques in the biomedical field are described through examples of applications performed at the ESRF synchrotron-based microspectroscopy platform (ID21 and ID22 beamlines).

Published
2012

5. Two differentially regulated phosphate transporters from the symbiotic fungus Hebeloma cylindrosporum and phosphorus acquisition by ectomycorrhizal Pinus pinaster

Author

Ingrid M. van Aarle, Claire Corratgé, Laurie Amenc, Rémi Alary, Hervé Sentenac, Elie Girgis El Kassis, Marie-Violaine Tatry, Sabine Zimmermann, Claude Plassard, Raphaël Lambilliotte, Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA), Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Développement et amélioration des plantes (UMR DAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Biogéochimie du Sol et de la Rhizosphère, Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2), Université de Montpellier (UM)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)

Subjects
0106 biological sciences, MESH: Sequence Analysis, DNA, MESH: Plant Roots, Plant Science, Plant Roots, 01 natural sciences, chemistry.chemical_compound, Gene Expression Regulation, Fungal, Mycorrhizae, Hebeloma, Phosphate Transport Proteins, MESH: Pinus, Cloning, Molecular, DNA, Fungal, MESH: Phosphorus, Expressed Sequence Tags, 2. Zero hunger, 0303 health sciences, Expressed sequence tag, Fungal protein, MESH: Symbiosis, biology, Phosphorus, Basidiomycota, MESH: Phosphate Transport Proteins, MESH: Fungal Proteins, heterologous characterization, MESH: Gene Expression Regulation, Fungal, DNA, Complementary, Hypha, Molecular Sequence Data, MESH: Hebeloma, MESH: Expressed Sequence Tags, soil P availability, Fungal Proteins, 03 medical and health sciences, Symbiosis, Botany, expression, MESH: Gene Library, Genetics, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, MESH: Cloning, Molecular, Gene Library, 030304 developmental biology, phosphate uptake, MESH: Molecular Sequence Data, ACL, fungi, Sequence Analysis, DNA, Cell Biology, ectomycorrhizal symbiosis, MESH: DNA, Complementary, Pinus, biology.organism_classification, Phosphate, Yeast, MESH: DNA, Fungal, chemistry, MESH: Mycorrhizae, phosphate transporter, 010606 plant biology & botany
Abstract

e-mail plassard@supagro.inra.fr; UMR DAP équipe DGB; International audience; Ectomycorrhizal symbiosis markedly improves plant phosphate uptake, but the molecular mechanisms underlying this benefit are still poorly understood. We identified two ESTs in a cDNA library prepared from the ectomycorrhizal basidiomycete Hebeloma cylindrosporum with significant similarities to phosphate transporters from the endomycorrhizal fungus Glomus versiforme and from non-mycorrhizal fungi. The full-length cDNAs corresponding to these two ESTs complemented a yeast phosphate transport mutant (Deltapho84). Measurements of (33)P-phosphate influx into yeast expressing either cDNA demonstrated that the encoded proteins, named HcPT1 and HcPT2, were able to mediate Pi:H(+) symport with different affinities for Pi (K(m) values of 55 and 4 mum, respectively). Real-time RT-PCR showed that Pi starvation increased the levels of HcPT1 transcripts in H. cylindrosporum hyphae grown in pure culture. Transcript levels of HcPT2 were less dependent on Pi availability. The two transporters were expressed in H. cylindrosporum associated with its natural host plant, Pinus pinaster, grown under low or high P conditions. The presence of ectomycorrhizae increased net Pi uptake rates into intact Pinus pinaster roots at low or high soil P levels. The expression patterns of HcPT1 and HcPT2 indicate that the two fungal phosphate transporters may be involved in uptake of phosphate from the soil solution under the two soil P availability conditions used.

Published
2009

6. Design of phosphorylated dendritic architectures to promote human monocyte activation

Author

Patrice Marchand, Ludovic Martinet, Fatima-Ezzahra L'Faqihi-Olive, Anne-Marie Caminade, Jean-Pierre Majoral, Olivier Rolland, Alexandrine Maraval, Jean-Jacques Fournié, Rémy Poupot, Laurent Griffe, Mary Poupot, Cédric-Olivier Turrin, Centre de Physiopathologie de Toulouse-Purpan (INSERM U563 - CNRS UMR1037), CHU Toulouse [Toulouse]-Institut Claudius Regaud-Hôpital Purpan [Toulouse], CHU Toulouse [Toulouse]-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre de lutte contre le cancer (CLCC)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Universitaire de Toulouse (CHU Toulouse)-Institut Claudius Regaud-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre de lutte contre le cancer (CLCC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Poupot, Mary, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV.MHEP.HEM] Life Sciences [q-bio]/Human health and pathology/Hematology, Adult, Dendrimers, MESH: Protein Transport, media_common.quotation_subject, Population, Cell Culture Techniques, MESH: NF-kappa B, Biology, 010402 general chemistry, MESH: Monocytes, 01 natural sciences, Biochemistry, Monocytes, Phosphorus metabolism, MESH: Fluorescein-5-isothiocyanate, Immune system, Phagocytosis, Dendrimer, Genetics, medicine, Humans, Phosphorylation, education, Internalization, MESH: Phagocytosis, MESH: Phosphorus, Molecular Biology, media_common, education.field_of_study, MESH: Cell Culture Techniques, Innate immune system, MESH: Humans, MESH: Phosphorylation, 010405 organic chemistry, MESH: Dendrimers, Monocyte, NF-kappa B, Phosphorus, MESH: Adult, [SDV.MHEP.HEM]Life Sciences [q-bio]/Human health and pathology/Hematology, 0104 chemical sciences, Cell biology, Protein Transport, Förster resonance energy transfer, medicine.anatomical_structure, Fluorescein-5-isothiocyanate, Biotechnology
Abstract

International audience; As first defensive line, monocytes are a pivotal cell population of innate immunity. Monocyte activation can be relevant to a range of immune conditions and responses. Here we present new insights into the activation of monocytes by a series of phosphonic acid-terminated, phosphorus-containing dendrimers. Various dendritic or subdendritic structures were synthesized and tested, revealing the basic structural requirements for monocyte activation. We showed that multivalent character and phosphonic acid capping of dendrimers are crucial for monocyte targeting and activation. Confocal videomicroscopy showed that a fluorescein-tagged dendrimer binds to isolated monocytes and gets internalized within a few seconds. We also found that dendrimers follow the phagolysosomial route during internalization by monocytes. Finally, we performed fluorescence resonance energy transfer (FRET) experiments between a specifically designed fluorescent dendrimer and phycoerythrin-coupled antibodies. We showed that the typical innate Toll-like receptor (TLR)-2 is clearly involved, but not alone, in the sensing of dendrimers by monocytes. In conclusion, phosphorus-containing dendrimers appear as precisely tunable nanobiotools able to target and activate human innate immunity and thus prove to be good candidates to develop new drugs for immunotherapies.

Published
2006

7. STEM and EDXS characterisation of physico-chemical reactions at the periphery of sol-gel derived Zn-substituted hydroxyapatites during interactions with biological fluids

Author

Patrice Laquerriere, Alexia Grandjean-Laquerriere, Dominique Laurent-Maquin, Emmanuelle Chassot, Jean-Marie Nedelec, Anne S. Grimault, Edouard Jallot, Laboratoire des Matériaux Inorganiques (LMI), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Clermont Université-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Interfaces biomatériaux/tissus hôtes, Université de Reims Champagne-Ardenne (URCA)-IFR53-Institut National de la Santé et de la Recherche Médicale (INSERM), and Laurent-Maquin, Dominique

Subjects
Chemical Phenomena, 02 engineering and technology, 01 natural sciences, Chemical reaction, MESH: Zinc, MESH: Body Fluids, Colloid and Surface Chemistry, Scanning transmission electron microscopy, Hydroxyapatites, MESH: Phosphorus, MESH: Hydroxyapatites, Magnesium, Chemistry, Physical, zinc, hydroxyapatite, MESH: Spectrometry, X-Ray Emission, Phosphorus, Surfaces and Interfaces, General Medicine, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Body Fluids, visual_art, MESH: Calcium, visual_art.visual_art_medium, [SDV.IB]Life Sciences [q-bio]/Bioengineering, 0210 nano-technology, Biotechnology, Biocompatibility, MESH: Microscopy, Electron, Scanning, chemistry.chemical_element, Mineralogy, electron probe microanalysis, Zinc, Sol–gel, 010402 general chemistry, Article, Metal, sol-gel, MESH: Chemistry, Physical, Physical and Theoretical Chemistry, Sol-gel, [SDV.IB] Life Sciences [q-bio]/Bioengineering, Spectrometry, X-Ray Emission, 0104 chemical sciences, chemistry, bioactivity, MESH: Spectrometr, Microscopy, Electron, Scanning, Calcium, Nuclear chemistry
Abstract

With its good properties of biocompatibility and bioactivity hydroxyapatite (HA) is highly used as bone substitutes and as coatings on metallic prostheses. In order to improve the bioactive properties of HA, we have elaborated Zn2+ doped hydroxyapatite. Zn2+ ions substitute for Ca2+ cations in the HA structure and four Zn concentrations (Zn/Zn + Ca) were prepared at 0.5, 1, 2 and 5 at.%. To study physico-chemical reactions at the materials periphery, we immersed the bioceramics into biological fluids for intervals from 1 day to 20 days. The surface changes were studied at the nanometer scale by scanning transmission electron microscopy associated with energy dispersive X-ray spectroscopy. After 20 days of immersion, we observed the formation of a calcium–phosphate layer at the periphery of the HA doped with 5% zinc. This layer contains magnesium and its thickness was around 200 nm. Formation of this Ca–P–Mg layer represents the bioactive properties of 5% Zn-substituted hydroxyapatite. This biologically active layer improves the properties of HA and will permit a chemical bond between the ceramic and bone.

Published
2005

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