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1. Epitaxial van der Waals heterostructures of Cr 2 Te 3 on two-dimensional materials

Author: Guillet, Quentin, Vojáček, Libor, Dosenovic, Djordje, Ibrahim, Fatima, Boukari, Hervé, Li, Jing, Choueikani, Fadi, Ohresser, Philippe, Ouerghi, Abdelkarim, Mesple, Florie, Renard, Vincent, Jacquot, Jean-François, Jalabert, Denis, Okuno, Hanako, Chshiev, Mairbek, Vergnaud, Céline, Bonell, Frédéric, Marty, Alain, Jamet, Matthieu, SPINtronique et TEchnologie des Composants (SPINTEC), 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), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Néel (NEEL), 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)-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), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Microbiologie Environnementale et Moléculaire (MEM), 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)), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)
Subjects: [PHYS]Physics [physics], [SPI]Engineering Sciences [physics]
Abstract: International audience; Abstract The recent discovery of superconductivity in paramagnetic UTe 2 turns spotlight on a serious candidate for spin-triplet state. To draw a complete picture of the superconducting state in UTe 2 precise knowledge of the electronic properties of the 5 f states of Uranium is missing. We report on x-ray absorption and magnetic circular dichroism experiments performed at the U M 4,5 edges at 2.7 K. At ambient pressure the 5 f electron count is found to be in-between 2.6 and 2.8. Partial delocalization of the 5 f electrons is further confirmed by the reduced value of the U orbital to spin magnetic moment ratio. The 5 f count is reduced by as large as 7 percent at the transition to a magnetically ordered state at P c ≈ 1.5 GPa. At pressures above 4 GPa, the 5 f count increases back towards U 3+ in the tetragonal phase. The observed “valence instabilities” and their interplay with magnetism seem to be important ingredients to understand the electronic structure in UTe 2 in different phases.
Published: 2023
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2. Epitaxial van der Waals heterostructures of Cr2Te3 on 2D materials

Author: Guillet, Quentin, Vojacek, Libor, Dosenovic, Djordje, Ibrahim, Fatima, Boukari, Herve, Li, Jing, Choueikani, Fadi, Ohresser, Philippe, Ouerghi, Abdelkarim, Mesple, Florie, Renard, Vincent, Jacquot, Jean-Francois, Jalabert, Denis, Okuno, Hanako, Chshiev, Mairbek, Vergnaud, Celine, Bonell, Frederic, Marty, Alain, Jamet, Matthieu, SPINtronique et TEchnologie des Composants (SPINTEC), 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), Microbiologie Environnementale et Moléculaire (MEM), 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), Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Néel (NEEL), 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)-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), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-20-CE24-0015,ELMAX,Contrôle électrique de l'aimantation dans les hétérostructures van der Waals épitaxiées(2020), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), ANR-21-ESRE-0025,2D-MAG,Two-dimensional magnetic materials(2021), European Project: 800945,NUMERICS, and European Project: 881603,H2020,H2020-SGA-FET-GRAPHENE-2019, GrapheneCore3(2020)
Subjects: [PHYS]Physics [physics], Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences
Abstract: Achieving large-scale growth of two-dimensional (2D) ferromagnetic materials with high Curie temperature (TC) and perpendicular magnetic anisotropy (PMA) is highly desirable for the development of ultra-compact magnetic sensors and magnetic memories. In this context, van der Waals (vdW) Cr2Te3 appears as a promising candidate. Bulk Cr2Te3 exhibits strong PMA and a TC of 180 K. Moreover, both PMA and TC might be adjusted in ultrathin films by engineering composition, strain, or applying an electric field. In this work, we demonstrate the molecular beam epitaxy (MBE) growth of vdW heterostructures of five-monolayer quasi-freestanding Cr2Te3 on three classes of 2D materials: graphene (semimetal), WSe2 (semiconductor) and Bi2Te3 (topological insulator). By combining structural and chemical analysis down to the atomic level with ab initio calculations, we confirm the single crystalline character of Cr2Te3 films on the 2D materials with sharp vdW interfaces. They all exhibit PMA and TC close to the bulk Cr2Te3 value of 180 K. Ab initio calculations confirm this PMA and show how its strength depends on strain. Finally, Hall measurements reveal a strong anomalous Hall effect, which changes sign at a given temperature. We theoretically explain this effect by a sign change of the Berry phase close to the Fermi level. This transition temperature depends on the 2D material in proximity, notably as a consequence of charge transfer. MBE-grown Cr2Te3/2D material bilayers constitute model systems for the further development of spintronic devices combining PMA, large spin-orbit coupling and sharp vdW interface., Comment: 18 pages, 13 figures and Supplemental Material
Published: 2023
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3. Stimulation par le rayonnement lumineux de la production de pigments bactériens pour la conception d’OLEDs

Author: Lajoie, Barbora, Andriantsiferana, Caroline, Loubière, Karine, El Garah, Fatima, Bouajila, Jaloul, Zissis, Georges, BUSO, DAVID, Blanchard, Laurence, de Groot, Arjan, Alaoui-Sossé, Badr, Attia, Rym, Laboratoire de Génie Chimique (LGC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Toulouse Biotechnology Institute (TBI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Service Central d'Analyse (SCA), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Lumière et Matière (LAPLACE-LM), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Microbiologie Environnementale et Moléculaire (MEM), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes (UGA), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Pathologies et épithéliums : prévention, innovation, traitements, évaluation (UR 4267) (PEPITE), Université de Franche-Comté (UFC), Institut National des Sciences Appliquées et de Technologie [Tunis] (INSAT), CNRS AAP 'Adaptation' Projet SUNRAY, and CNRS
Subjects: [SDV.BIO]Life Sciences [q-bio]/Biotechnology, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology
Abstract: International audience
Published: 2023

4. Crystal-Chemical and Biological Controls of Elemental Incorporation into Magnetite Nanocrystals

Author: Matthieu Amor, J. Frederick W. Mosselmans, Ernesto Scoppola, Chenghao Li, Damien Faivre, Daniel M. Chevrier, 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), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), DIAMOND Light source, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Microbiologie Environnementale et Moléculaire (MEM), 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)), Fondation pour la Recherche Médicale (ARF201909009123), and European Union Marie-Skłodowska Curie Action International Fellowship (MSCA-IF Project 797431: BioNanoMagnets)
Subjects: Biomineralization, Crystal Field Theory, [SDV]Life Sciences [q-bio], Lattice strain theory, General Engineering, General Physics and Astronomy, General Materials Science, Magnetotactic Bacteria, Magnetite Nanoparticles, Trace Element Partitioning
Abstract: International audience; Magnetite nanoparticles possess numerous fundamental, biomedical, and industrial applications, many of which depend on tuning the magnetic properties. This is often achieved by the incorporation of trace and minor elements into the magnetite lattice. Such incorporation was shown to depend strongly on the magnetite formation pathway (i.e., abiotic vs biological), but the mechanisms controlling element partitioning between magnetite and its surrounding precipitation solution remain to be elucidated. Here, we used a combination of theoretical modeling (lattice and crystal field theories) and experimental evidence (high-resolution inductively coupled plasma–mass spectrometry and X-ray absorption spectroscopy) to demonstrate that element incorporation into abiotic magnetite nanoparticles is controlled principally by cation size and valence. Elements from the first series of transition metals (Cr to Zn) constituted exceptions to this finding, as their incorporation appeared to be also controlled by the energy levels of their unfilled 3d orbitals, in line with crystal field mechanisms. We finally show that element incorporation into biological magnetite nanoparticles produced by magnetotactic bacteria (MTB) cannot be explained by crystal–chemical parameters alone, which points to the biological control exerted by the bacteria over the element transfer between the MTB growth medium and the intracellular environment. This screening effect generates biological magnetite with a purer chemical composition in comparison to the abiotic materials formed in a solution of similar composition. Our work establishes a theoretical framework for understanding the crystal–chemical and biological controls of trace and minor cation incorporation into magnetite, thereby providing predictive methods to tailor the composition of magnetite nanoparticles for improved control over magnetic properties.
Published: 2023
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5. Interplay of surface interaction and magnetic torque in single-cell motion of magnetotactic bacteria in microfluidic confinement

Author: Elisa Cerdá-Doñate, Mohammad A Charsooghi, Agnese Codutti, Hubert M Taïeb, Tom Robinson, Damien Faivre, Stefan Klumpp, Department of Biomaterials, Max‐Planck‐Institute of Colloids and Interfaces, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), and Georg-August-University = Georg-August-Universität Göttingen
Subjects: Magnetics, Magnetic Fields, Torque, General Immunology and Microbiology, General Neuroscience, [SDV]Life Sciences [q-bio], Gram-Negative Bacteria, Microfluidics, General Medicine, Magnetospirillum, General Biochemistry, Genetics and Molecular Biology
Abstract: International audience; Swimming microorganisms often experience complex environments in their natural habitat. The same is true for microswimmers in envisioned biomedical applications. The simple aqueous conditions typically studied in the lab differ strongly from those found in these environments and often exclude the effects of small volume confinement or the influence that external fields have on their motion. In this work, we investigate magnetically steerable microswimmers, specifically magnetotactic bacteria, in strong spatial confinement and under the influence of an external magnetic field. We trap single cells in micrometer-sized microfluidic chambers and track and analyze their motion, which shows a variety of different trajectories, depending on the chamber size and the strength of the magnetic field. Combining these experimental observations with simulations using a variant of an active Brownian particle model, we explain the variety of trajectories by the interplay between the wall interactions and the magnetic torque. We also analyze the pronounced cell-to-cell heterogeneity, which makes single-cell tracking essential for an understanding of the motility patterns. In this way, our work establishes a basis for the analysis and prediction of microswimmer motility in more complex environments.
Published: 2022
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6. Iron‐biomineralizing organelle in magnetotactic bacteria: function, synthesis and preservation in ancient rock samples

Author: François P. Mathon, Christopher T. Lefèvre, Vincent Busigny, Caroline L. Monteil, Matthieu Amor, 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), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Geophysical Sciences [Chicago], University of Chicago, Microbiologie Environnementale et Moléculaire (MEM), 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)), ANR-18-CE31-0003,SIGMAG,SIGNATURE DES MAGNETITES PRODUITES PAR LES BACTERIES MAGNETOTACTIQUES : PERSPECTIVES CHIMIQUES ET ISOTOPIQUES(2018), ANR-19-CE01-0005,PHOSTORE,Piégeage du phosphore : contribution des bactéries magnétotactiques dans les zones de transition oxique-anoxique(2019), 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), Institut de Physique du Globe de Paris (IPGP), and Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
Subjects: Greigite, Mineralization (geology), Magnetotactic bacteria, Iron, Microorganism, Geochemistry, Sulfides, Biology, Microbiology, 03 medical and health sciences, chemistry.chemical_compound, Organelle, Magnetite Nanoparticles, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, Magnetite, 0303 health sciences, Bacteria, 030306 microbiology, Magnetic Phenomena, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, chemistry, Sedimentary rock, Magnetosomes, Function (biology)
Abstract: Magnetotactic bacteria (MTB) are ubiquitous aquatic microorganisms that incorporate iron from their environment to synthesize intracellular nanoparticles of magnetite (Fe3 O4 ) or greigite (Fe3 S4 ) in a genetically controlled manner. Magnetite and greigite magnetic phases allow MTB to swim towards redox transition zones where they thrive. MTB may represent some of the oldest microorganisms capable of synthesizing minerals on Earth and have been proposed to significantly impact the iron biogeochemical cycle by immobilizing soluble iron into crystals that subsequently fossilize in sedimentary rocks. In the present article, we describe the distribution of MTB in the environment and discuss the possible function of the magnetite and greigite nanoparticles. We then provide an overview of the chemical mechanisms leading to iron mineralization in MTB. Finally, we update the methods used for the detection of MTB crystals in sedimentary rocks and present their occurrences in the geological record.
Published: 2020
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7. Thiol Reductases in Deinococcus Bacteria and Roles in Stress Tolerance

Author: Arjan De Groot, Pascal REY, Nicolas Rouhier, Laurence Blanchard, Microbiologie Environnementale et Moléculaire (MEM), 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), Interactions Arbres-Microorganismes (IAM), Université de Lorraine (UL)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Protéines de Protection des Végétaux (PPV), and ANR-19-CE12-0010,NOVOREP,Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress(2019)
Subjects: bacillithiol, Physiology, Clinical Biochemistry, thiol, peroxidase, Cell Biology, thioredoxin, Biochemistry, protein redox status, reductase, bacteria, oxidative stress, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Deinococcus, Molecular Biology, cysteine
Abstract: International audience; Deinococcus species possess remarkable tolerance to extreme environmental conditions that generate oxidative damage to macromolecules. Among enzymes fulfilling key functions in metabolism regulation and stress responses, thiol reductases (TRs) harbour catalytic cysteines modulating the redox status of Cys and Met in partner proteins. We present here a detailed description of Deinococcus TRs regarding gene occurrence, sequence features, and physiological functions that remain poorly characterised in this genus. Two NADPH-dependent thiol-based systems are present in Deinococcus. One involves thioredoxins, disulfide reductases providing electrons to protein partners involved notably in peroxide scavenging or in preserving protein redox status. The other is based on bacillithiol, a low-molecular-weight redox molecule, and bacilliredoxin, which together protect Cys residues against overoxidation. Deinococcus species possess various types of thiol peroxidases whose electron supply depends either on NADPH via thioredoxins or on NADH via lipoylated proteins. Recent data gained on deletion mutants confirmed the importance of TRs in Deinococcus tolerance to oxidative treatments, but additional investigations are needed to delineate the redox network in which they operate, and their precise physiological roles. The large palette of Deinococcus TR representatives very likely constitutes an asset for the maintenance of redox homeostasis in harsh stress conditions.
Published: 2022
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8. Root responses to aluminium and iron stresses require the SIZ1 SUMO ligase to modulate the STOP1 transcription factor

Author: Laurent Nussaume, Marien Have, Nathalie Duong, Pascale David, Thierry Desnos, Nathalie Leonhardt, Caroline Mercier, Steffen Abel, Brice Roux, Laurence Blanchard, Laura Cuyas, Léa Le Poder, Sylvain Pluchon, Christin Naumann, 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), Plant Environmental Physiology and Stress Signaling (PEPSS), 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)), Microbiologie Environnementale et Moléculaire (MEM), Leibniz Institute of Plant Biochemistry (IPB), Laboratoire de Nutrition Végétale, Agroinnovation International − TIMAC AGRO, Saint-Malo, France, ANR-18-CE20-0023,BioPhyt,Mode d'action de phytostimulants biosourcés sur une voie de signalisation multi-stress(2018), 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), Signalisation de l'Adaptation des Végétaux à l'Environnement (SAVE), and Biologie végétale et microbiologie environnementale - UMR7265 (BVME)
Subjects: 0106 biological sciences, [SDV]Life Sciences [q-bio], Arabidopsis, SUMO protein, Plant Science, Plant Roots, 01 natural sciences, SIZ1, law.invention, Ligases, 03 medical and health sciences, iron, ALMT1, Gene Expression Regulation, Plant, Stress, Physiological, law, Genetics, [SDV.BV]Life Sciences [q-bio]/Vegetal Biology, Transcription factor, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, phosphate, chemistry.chemical_classification, 0303 health sciences, DNA ligase, STOP1, biology, Arabidopsis Proteins, aluminium, Sumoylation, Cell Biology, biology.organism_classification, root, Hedgehog signaling pathway, Forward genetics, Ubiquitin ligase, Cell biology, chemistry, SUMO, Mutation, biology.protein, Suppressor, Aluminum, Signal Transduction, Transcription Factors, 010606 plant biology & botany
Abstract: International audience; STOP1, an Arabidopsis transcription factor favouring root growth tolerance against Al toxicity, acts in the response to iron under low Pi (Pi). Previous studies have shown that Al and Fe regulate the stability and accumulation of STOP1 in roots, and that the STOP1 protein is sumoylated by an unknown E3 ligase. Here, using a forward genetics suppressor screen, we identified the E3 SUMO (small ubiquitin-like modifier) ligase SIZ1 as a modulator of STOP1 signalling. Mutations in SIZ1 increase the expression of ALMT1 (a direct target of STOP1) and root growth responses to Al and Fe stress in a STOP1-dependent manner. Moreover, loss-of-function mutations in SIZ1 enhance the abundance of STOP1 in the root tip. However, no sumoylated STOP1 protein was detected by Western blot analysis in our sumoylation assay in Escherichia coli, suggesting the presence of a more sophisticated mechanism. We conclude that the sumo ligase SIZ1 negatively regulates STOP1 signalling, at least in part by modulating STOP1 protein in the root tip. Our results will allow a better understanding of this signalling pathway.
Published: 2021
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9. Shaping Magnetite with Poly-l-arginine and pH: From Small Single Crystals to Large Mesocrystals

Author: Elena Macías-Sánchez, Lucas Kuhrts, Nadezda V. Tarakina, Ann M. Hirt, Damien Faivre, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Department of Biomaterials [Potsdam], Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Microbiologie Environnementale et Moléculaire (MEM), 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), ERA-Chemistry Framework (Project Number FA 835/12-1), 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: Materials science, Letter, Magnetotactic bacteria, [SDV]Life Sciences [q-bio], 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Nanomaterials, Colloid, chemistry.chemical_compound, chemistry, Chemical engineering, Transmission electron microscopy, General Materials Science, Particle size, Physical and Theoretical Chemistry, 0210 nano-technology, Mesocrystal, ComputingMilieux_MISCELLANEOUS, Superparamagnetism, Magnetite
Abstract: Control over particle size, size distribution, and colloidal stability are central aims in producing functional nanomaterials. Recently, biomimetic approaches have been successfully used to enhance control over properties in the synthesis of those materials. Magnetotactic bacteria produce protein-stabilized magnetite away from its thermodynamic equilibrium structure. Mimicking the bacteria’s proteins using poly-l-arginine we show that by simply increasing the pH, the dimensions of magnetite increase and a single- to mesocrystal transformation is induced. Using synchrotron X-ray diffraction and transmission electron microscopy, we show that magnetite nanoparticles with narrow size distributions and average diameters of 10 ± 2 nm for pH 9, 20 ± 2 nm for pH 10, and up to 40 ± 4 nm for pH 11 can be synthesized. We thus selectively produce superparamagnetic and stable single-domain particles merely by controlling the pH. Remarkably, while an increase in pH brings about a thermodynamically driven decrease in size for magnetite without additives, this dependency on pH is inverted when poly-l-arginine is present., The Journal of Physical Chemistry Letters, 10 (18), ISSN:1948-7185
Published: 2019
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10. Swimming with magnets: From biological organisms to synthetic devices

Author: Damien Faivre, Mathieu Bennet, Christopher T. Lefèvre, Stefan Klumpp, Department of Nonlinear Dynamics [Göttingen], Max Planck Institute for Dynamics and Self-Organization (MPIDS), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Department of Theory and Bio-Systems [Potsdam], Max Planck Institute of Colloids and Interfaces, Microbiologie Environnementale et Moléculaire (MEM), 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), Department of Biomaterials [Potsdam], Our own work underlying this review was supported by the Max Planck Society, the European Research Council (grant MB2 N°256915 to DF), Deutsche Forschungsgemeinschaft (grants no. FA 835/7-1 and 7-2 and KL 818/2-1 and 2-2 within the Priority Programm 1726 on microswimmers, to DF and SK, respectively) and by the French National Research Agency (grant ANR-16-TERC-0025-01 to CTL and grant ANR-14-CE35-0018-01 to DF and CTL)., ANR-14-CE35-0018,GroMa,Greigite or magnetite: Environmental and genetic determinants controlling biomineralization in magnetotactic bacteria(2014), European Project: 256915,EC:FP7:ERC,ERC-2010-StG_20091028,MB2(2011), 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: [PHYS]Physics [physics], Physics, Collective behavior, Magnetotactic bacteria, Biological organism, Field (physics), 010308 nuclear & particles physics, Magnetism, General Physics and Astronomy, Propulsion, 01 natural sciences, Magnet, 0103 physical sciences, Magnetic nanoparticles, Biochemical engineering, 010306 general physics
Abstract: International audience; The movement of microorganisms is not only an essential aspect of life, it also serves as a fruitful model for the development of synthetic microswimmers or microrobots with potential applications in environmental and medical fields. Here, we review the field of the magnetic microswimmers, which as indicated by the adjective, represents a dedicated branch of the general microswimmers where magnetism plays a role either for the orientation or for the locomotion of the swimmers. These swimmers, on the one hand, provide model system for studying the interplay of external physical forces with biological processes and are, on the other hand, attractive for various applications due to the possibility of remote steering by magnetic fields.The review is structured in such a way that we first present the physical background associated with the microswimmers in general, with their locomotion at low Reynolds numbers and their orientation by magnetic fields and by other mechanisms. We then review illustrative examples of magnetic swimmers, starting with the biological ones, the magnetotactic bacteria, which are bacteria forming intracellular magnetic nanoparticles to orient in magnetic field. We continue with the hybrid and synthetic microswimmers, where magnetism again plays a role for the orientation / directionality, but can also provide propulsion mechanisms. We finally emphasize the control of multiple swimmers/devices along independent trajectories as well as their interactions and collective behavior. We will look forward to the continuous development of the field and hope that this review will stimulate further research in this vibrant research area.
Published: 2019
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11. Bacteriophage‐Templated Assembly of Magnetic Nanoparticles and Their Actuation Potential

Author: Christophe Tarabout, Katja M. Arndt, Mathieu Bennet, Marc Widdrat, Frank Mickoleit, Dirk Schüler, Agata Olszewska-Widdrat, Damien Faivre, Victoria Reichel, Leibniz Institute for Agricultural Engineering and Bioeconomy, Department of Biomaterials [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, University of Bayreuth, University of Potsdam = Universität Potsdam, Biologie 1, Mikrobiologie, Ludwig-Maximilians-Universität München (LMU), 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), University of Potsdam, 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: Materials science, biology, Renewable Energy, Sustainability and the Environment, viruses, [SDV]Life Sciences [q-bio], Magnetosome, Energy Engineering and Power Technology, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, biology.organism_classification, equipment and supplies, 01 natural sciences, 0104 chemical sciences, Biomaterials, Bacteriophage, chemistry.chemical_compound, chemistry, Materials Chemistry, Magnetic nanoparticles, 0210 nano-technology, human activities, Magnetite
Abstract: International audience; Magnetic chains are of fundamental and technological interest. However, 1D assemblies of magnetic nanoparticles are only metastable such that their controlled organization requires the use of templates. Bacteriophages are human-inoffensive viruses with a filamentous morphology that have been shown to exhibit great potential in materials research. Here, we thus utilized the M13 phage as a model for the formation of actuated magnetite nanoparticle superstructures. First, we built a sperm-like ensemble by covalently attaching magnetic nanoparticles to the head of the phage. Second, chain-like assemblies are obtained based on the electrostatic interactions between positively-charged magnetite nanoparticles attached to the negatively-charged phage surface. The nanoparticles-phages assembly is steered by external magnetic fields. We anticipate such materials can find applications in nanotechnology or nanomedicine.
Published: 2021
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12. Mechanism and dynamics of fatty acid photodecarboxylase

Author: Sébastien Boutet, Catherine Berthomieu, Laura Antonucci, A. Gorel, Manuel Joffre, Marco Cammarata, A. Benachir, Sergio Carbajo, Solène L. Y. Moulin, Martin Weik, Michel Sliwa, Stephane Cuine, Yonghua Li-Beisson, Nicolas Coquelle, Didier Nurizzo, P. Samire, Jacques-Philippe Colletier, Alexey Aleksandrov, Robert L. Shoeman, Guillaume Gotthard, Antoine Royant, Marten H. Vos, Bo Zhuang, M. Hilpert, Adeline Bonvalet, Ilme Schlichting, Xavier Solinas, Martin Byrdin, Pascal Arnoux, Gilles Peltier, Pierre Legrand, F. Beisson, Klaus Brettel, R. Hienerwadel, Thomas R. M. Barends, R.B. Doak, Lutz Foucar, T. Domratcheva, Damien Sorigué, Marco Kloos, Stéphanie Blangy, Giorgio Schirò, Kyprianos Hadjidemetriou, Bertrand Légeret, Thomas J. Lane, Marie Luise Grünbein, Pavel Müller, Elisabeth Hartmann, Environnement, Bioénergie, Microalgues et Plantes (EBMP), 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), 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), European Synchroton Radiation Facility [Grenoble] (ESRF), Laboratoire d'Optique et Biosciences (LOB), École polytechnique (X)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), 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), SLAC National Accelerator Laboratory (SLAC), Stanford University, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Medizinische Forschung, Max-Planck-Gesellschaft, Luminy Génétique et Biophysique des Plantes (LGBP), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Interactions Protéine Métal (IPM), Department of Chemistry, Lomonosov Moscow State University, Lomonosov Moscow State University (MSU), Microbiologie Environnementale et Moléculaire (MEM), STepLADDER (724362), European Research Council, 724362, European Research Council, SNAPsHOTs, Agence Nationale de la Recherche, Photoalkane, Agence Nationale de la Recherche, SignalBioNRJ, Agence Nationale de la Recherche, BioXFEL, Agence Nationale de la Recherche, Ministère de l’Education Nationale, de l’Enseignement Supérieur et de la Recherche, ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), ANR-18-CE11-0021,SNAPsHOTs,Dynamique structurale de l'acide gras photodécarboxylase(2018), ANR-18-CE43-0008,PHOTOALKANE,Production biosourcée d'hydrocarbures basée sur une nouvelle photoenzyme(2018), ANR-15-CE32-0004,BioXFEL,Caractérisation d'états intermédiaires de protéines fluorescentes en utilisant des lasers à électrons libres X et les spectroscopies UV-visible et infrarouge ultra-rapides(2015), European Project: 724362,STePLADDER - H2020-EU.1.1., Bioénergie et Microalgues (EBM), 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), ILL, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Vos, Marten, Infrastructure Française pour la Biologie Structurale Intégrée - - FRISBI2010 - ANR-10-INBS-0005 - INBS - VALID, APPEL À PROJETS GÉNÉRIQUE 2018 - Dynamique structurale de l'acide gras photodécarboxylase - - SNAPsHOTs2018 - ANR-18-CE11-0021 - AAPG2018 - VALID, APPEL À PROJETS GÉNÉRIQUE 2018 - Production biosourcée d'hydrocarbures basée sur une nouvelle photoenzyme - - PHOTOALKANE2018 - ANR-18-CE43-0008 - AAPG2018 - VALID, Caractérisation d'états intermédiaires de protéines fluorescentes en utilisant des lasers à électrons libres X et les spectroscopies UV-visible et infrarouge ultra-rapides - - BioXFEL2015 - ANR-15-CE32-0004 - AAPG2015 - VALID, and Solving The Pathway of LADDERane biosynthesis - STePLADDER - H2020-EU.1.1. - 724362 - INCOMING
Subjects: Models, Molecular, Light, Carboxy-Lyases, Protein Conformation, Decarboxylation, Chlorella, Reaction intermediate, Flavin group, Crystallography, X-Ray, 010402 general chemistry, Photochemistry, 01 natural sciences, [PHYS] Physics [physics], Electron Transport, 03 medical and health sciences, Catalytic Domain, Alkanes, [SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Amino Acids, Alkyl, 030304 developmental biology, chemistry.chemical_classification, [PHYS]Physics [physics], Photons, 0303 health sciences, Multidisciplinary, Algal Proteins, Fatty Acids, Temperature, Fatty acid, Substrate (chemistry), Hydrogen Bonding, Carbon Dioxide, Chromophore, Electron transport chain, 0104 chemical sciences, Bicarbonates, Amino Acid Substitution, chemistry, 13. Climate action, Biocatalysis, Flavin-Adenine Dinucleotide, Mutant Proteins, Oxidation-Reduction
Abstract: Light makes light work of fatty acids Photosynthetic organisms are notable for their ability to capture light energy and use it to power biosynthesis. Some algae have gone a step beyond photosynthesis and can use light to initiate enzymatic photodecarboxylation of fatty acids, producing long-chain hydrocarbons. To understand this transformation, Sorigué et al. brought to bear an array of structural, computational, and spectroscopic techniques and fully characterized the catalytic cycle of the enzyme. These experiments are consistent with a mechanism starting with electron transfer from the fatty acid to a photoexcited oxidized flavin cofactor. Decarboxylation yields an alkyl radical, which is then reduced by back electron transfer and protonation rather than hydrogen atom transfer. The wealth of experimental data explains how algae harness light energy to produce alka(e)nes and provides an appealing model system for understanding enzyme-catalyzed photochemistry more generally. Science , this issue p. eabd5687
Published: 2021
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13. Coexistence of SOS-Dependent and SOS-Independent Regulation of DNA Repair Genes in Radiation-Resistant

Author: Arjan de Groot, Laurence Blanchard, Microbiologie Environnementale et Moléculaire (MEM), 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), ANR-19-CE12-0010,NOVOREP,Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress(2019), 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: 0301 basic medicine, SOS response, translesion polymerase, SOS-independent, metallopeptidase IrrE, DNA Repair, DNA repair, DNA damage, DNA polymerase, QH301-705.5, DnaE2, [SDV]Life Sciences [q-bio], 030106 microbiology, repressor DdrO, Review, Deinococcus, Radiation Tolerance, 03 medical and health sciences, SOS mutagenesis, A Deinococcus, Biology (General), SOS Response, Genetics, radiation resistance, biology, Mutagenesis, Deinococcus radiodurans, General Medicine, Gene Expression Regulation, Bacterial, biology.organism_classification, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Cell biology, 030104 developmental biology, biology.protein, bacteria, Repressor lexA
Abstract: Deinococcus bacteria are extremely resistant to radiation and able to repair a shattered genome in an essentially error-free manner after exposure to high doses of radiation or prolonged desiccation. An efficient, SOS-independent response mechanism to induce various DNA repair genes such as recA is essential for radiation resistance. This pathway, called radiation/desiccation response, is controlled by metallopeptidase IrrE and repressor DdrO that are highly conserved in Deinococcus. Among various Deinococcus species, Deinococcus radiodurans has been studied most extensively. Its genome encodes classical DNA repair proteins for error-free repair but no error-prone translesion DNA polymerases, which may suggest that absence of mutagenic lesion bypass is crucial for error-free repair of massive DNA damage. However, many other radiation-resistant Deinococcus species do possess translesion polymerases, and radiation-induced mutagenesis has been demonstrated. At least dozens of Deinococcus species contain a mutagenesis cassette, and some even two cassettes, encoding error-prone translesion polymerase DnaE2 and two other proteins, ImuY and ImuB-C, that are probable accessory factors required for DnaE2 activity. Expression of this mutagenesis cassette is under control of the SOS regulators RecA and LexA. In this paper, we review both the RecA/LexA-controlled mutagenesis and the IrrE/DdrO-controlled radiation/desiccation response in Deinococcus.
Published: 2021
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14. Stokesian dynamics simulations of a magnetotactic bacterium

Author: Sarah Mohammadinejad, Stefan Klumpp, Damien Faivre, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Georg-August-University = Georg-August-Universität Göttingen, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), University of Göttingen - Georg-August-Universität Göttingen, 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), and Georg-August-University [Göttingen]
Subjects: Field (physics), Magnetotactic bacteria, Stokesian dynamics, [SDV]Life Sciences [q-bio], Biophysics, 02 engineering and technology, Flagellum, Models, Biological, Computer Science::Digital Libraries, Quantitative Biology::Cell Behavior, 03 medical and health sciences, Torque, General Materials Science, 14. Life underwater, Elasticity (economics), 030304 developmental biology, Physics, 0303 health sciences, Physics::Biological Physics, Bacteria, Magnetic moment, Chemotaxis, Surfaces and Interfaces, General Chemistry, Mechanics, 021001 nanoscience & nanotechnology, Magnetic field, Magnetic Fields, 0210 nano-technology, Regular Article - Living Systems, Biotechnology
Abstract: Abstract The swimming of bacteria provides insight into propulsion and steering under the conditions of low-Reynolds number hydrodynamics. Here we address the magnetically steered swimming of magnetotactic bacteria. We use Stokesian dynamics simulations to study the swimming of single-flagellated magnetotactic bacteria (MTB) in an external magnetic field. Our model MTB consists of a spherical cell body equipped with a magnetic dipole moment and a helical flagellum rotated by a rotary motor. The elasticity of the flagellum as well as magnetic and hydrodynamic interactions is taken into account in this model. We characterized how the swimming velocity is dependent on parameters of the model. We then studied the U-turn motion after a field reversal and found two regimes for weak and strong fields and, correspondingly, two characteristic time scales. In the two regimes, the U-turn time is dominated by the turning of the cell body and its magnetic moment or the turning of the flagellum, respectively. In the regime for weak fields, where turning is dominated by the magnetic relaxation, the U-turn time is approximately in agreement with a theoretical model based on torque balance. In the strong-field regime, strong deformations of the flagellum are observed. We further simulated the swimming of a bacterium with a magnetic moment that is inclined relative to the flagellar axis. This scenario leads to intriguing double helical trajectories that we characterize as functions of the magnetic moment inclination and the magnetic field. For small inclination angles ($$\lesssim {20^{\circ }}$$ ≲ 20 ∘ ) and typical field strengths, the inclination of the magnetic moment has only a minor effect on the swimming of MTB in an external magnetic field. Large inclination angles result in a strong reduction in the velocity in direction of the magnetic field, consistent with recent observations that bacteria with large inclination angles use a different propulsion mechanism. Graphic abstract
Published: 2021
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15. Redox signaling through zinc activates the radiation response in Deinococcus bacteria

Author: Romaric, Magerand, Pascal, Rey, Laurence, Blanchard, Arjan, de Groot, Microbiologie Environnementale et Moléculaire (MEM), 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), Protéines de Protection des Végétaux (PPV), ANR-19-CE12-0010,NOVOREP,Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress(2019), 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: DNA Replication, Science, [SDV]Life Sciences [q-bio], Models, Biological, Radiation Tolerance, Article, Radiation, Ionizing, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, ComputingMilieux_MISCELLANEOUS, Bacteria, Environmental microbiology, DNA damage and repair, Gene Expression Regulation, Bacterial, Proteases, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Gene regulation, Oxidative Stress, Zinc, Mutagenesis, Metals, Prokaryote, Metalloproteases, Medicine, Deinococcus, [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM], Structural biology, Oxidation-Reduction, Microbial genetics, DNA Damage, Signal Transduction
Abstract: International audience; Deinococcus bacteria are extremely resistant to radiation and other DNA damage-and oxidative stress-generating conditions. An efficient SOS-independent response mechanism inducing expression of several DNA repair genes is essential for this resistance, and is controlled by metalloprotease IrrE that cleaves and inactivates transcriptional repressor DdrO. Here, we identify the molecular signaling mechanism that triggers DdrO cleavage. We show that reactive oxygen species (ROS) stimulate the zinc-dependent metalloprotease activity of IrrE in Deinococcus. Sudden exposure of Deinococcus to zinc excess also rapidly induces DdrO cleavage, but is not accompanied by ROS production and DNA damage. Further, oxidative treatment leads to an increase of intracellular free zinc, indicating that IrrE activity is very likely stimulated directly by elevated levels of available zinc ions. We conclude that radiation and oxidative stress induce changes in redox homeostasis that result in IrrE activation by zinc in Deinococcus. We propose that a part of the zinc pool coordinated with cysteine thiolates is released due to their oxidation. Predicted regulation systems involving IrrE-and DdrO-like proteins are present in many bacteria, including pathogens, suggesting that such a redox signaling pathway including zinc as a second messenger is widespread and participates in various stress responses.
Published: 2021
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16. Identification and elimination of genomic regions irrelevant for magnetosome biosynthesis by large-scale deletion in Magnetospirillum gryphiswaldense

Author: Zwiener, Theresa, Mickoleit, Frank, Dziuba, Marina, Rückert, Christian, Busche, Tobias, Kalinowski, Jörn, Faivre, Damien, Uebe, René, Schüler, Dirk, Universität Bayreuth, Russian Academy of Sciences [Moscow] (RAS), Universität Bielefeld = Bielefeld University, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), European Project: 0955098(2010), 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: Genome reduction, [SDV]Life Sciences [q-bio], lcsh:QR1-502, Genomics, lcsh:Microbiology, Genes, Bacterial, Multigene Family, Mutation, Operon, Magnetosomes, Magnetospirillum, Magnetospirillum gryphiswaldense, Genome, Bacterial, Research Article
Abstract: Background Magnetosome formation in the alphaproteobacterium Magnetospirillum gryphiswaldense is controlled by more than 30 known mam and mms genes clustered within a large genomic region, the ‘magnetosome island’ (MAI), which also harbors numerous mobile genetic elements, repeats, and genetic junk. Because of the inherent genetic instability of the MAI caused by neighboring gene content, the elimination of these regions and their substitution by a compact, minimal magnetosome expression cassette would be important for future analysis and engineering. In addition, the role of the MAI boundaries and adjacent regions are still unclear, and recent studies indicated that further auxiliary determinants for magnetosome biosynthesis are encoded outside the MAI. However, techniques for large-scale genome editing of magnetic bacteria are still limited, and the full complement of genes controlling magnetosome formation has remained uncertain. Results Here we demonstrate that an allelic replacement method based on homologous recombination can be applied for large-scale genome editing in M. gryphiswaldense. By analysis of 24 deletion mutants covering about 167 kb of non-redundant genome content, we identified genes and regions inside and outside the MAI irrelevant for magnetosome biosynthesis. A contiguous stretch of ~ 100 kb, including the scattered mam and mms6 operons, could be functionally substituted by a compact and contiguous ~ 38 kb cassette comprising all essential biosynthetic gene clusters, but devoid of interspersing irrelevant or problematic gene content. Conclusions Our results further delineate the genetic complement for magnetosome biosynthesis and will be useful for future large-scale genome editing and genetic engineering of magnetosome biosynthesis. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02124-2.
Published: 2021
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17. Discovery and characterization of UipA, a uranium- and iron-binding PepSY protein involved in uranium tolerance by soil bacteria

Author: David Lemaire, Virginie Chapon, Laurie Piette, Jean Armengaud, Pierre Legrand, Abbas Mohamad Ali, Philippe Ortet, Mohamed Barakat, Béatrice Alpha-Bazin, Laureline Février, Catherine Berthomieu, Nicolas Bremond, Christophe Den Auwer, Nicolas Gallois, Magali Floriani, Nicolas Theodorakopoulos, Pascal Arnoux, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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), Interactions Protéine Métal (IPM), 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)), Service de Pharmacologie et Immunoanalyse (SPI), Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay-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 Paris-Saclay-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), Laboratoire d'Ecologie Microbienne de la Rhizosphère et d'Environnements Extrêmes (LEMIRE), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire de recherche sur les transferts de radionucléides dans les écosystèmes terrestres (LR2T), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire d'écotoxicologie des radionucléides (PRP-ENV/SERIS/LECO), Institut de Chimie de Nice (ICN), 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 de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Microbiologie Environnementale et Moléculaire (MEM), 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), Laboratoire de recherche sur les transferts des radionucléides dans les écosystèmes terrestres (IRSN/PSE-ENV/SRTE/LR2T), Service de recherche sur les transferts et les effets des radionucléides sur les écosystèmes (IRSN/PSE-ENV/SRTE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Laboratoire d'écotoxicologie des radionucléides (IRSN/PRP-ENV/SERIS/LECO), Service de Recherche et d'Expertise sur les Risques environnementaux (IRSN/PRP-ENV/SERIS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)
Subjects: inorganic chemicals, Iron, chemistry.chemical_element, Biology, Proteomics, Microbiology, complex mixtures, Article, Metal, 03 medical and health sciences, chemistry.chemical_compound, Soil, proteomics, environmental bacteria, Iron-Binding Proteins, metal-binding protein, crystallography, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, 0303 health sciences, Bacteria, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], 030306 microbiology, technology, industry, and agriculture, Correction, Uranium, Phosphate, biology.organism_classification, Uranyl, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Transmembrane protein, chemistry, Membrane protein, Biochemistry, visual_art, visual_art.visual_art_medium, uranium tolerance
Abstract: International audience; Uranium is a naturally occurring radionuclide. Its redistribution, primarily due to human activities, can have adverse effects on human and non-human biota, which poses environmental concerns. The molecular mechanisms of uranium tolerance and the cellular response induced by uranium exposure in bacteria are not yet fully understood. Here, we carried out a comparative analysis of four actinobacterial strains isolated from metal and radionuclide-rich soils that display contrasted uranium tolerance phenotypes. Comparative proteogenomics showed that uranyl exposure affects 39–47% of the total proteins, with an impact on phosphate and iron metabolisms and membrane proteins. This approach highlighted a protein of unknown function, named UipA, that is specific to the uranium-tolerant strains and that had the highest positive fold-change upon uranium exposure. UipA is a single-pass transmembrane protein and its large C-terminal soluble domain displayed a specific, nanomolar binding affinity for UO$_2^{2+}$ and Fe$^{3+}$. ATR-FTIR and XAS-spectroscopy showed that mono and bidentate carboxylate groups of the protein coordinated both metals. The crystal structure of UipA, solved in its apo state and bound to uranium, revealed a tandem of PepSY domains in a swapped dimer, with a negatively charged face where uranium is bound through a set of conserved residues. This work reveals the importance of UipA and its PepSY domains in metal binding and radionuclide tolerance.
Published: 2021
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18. Atypical Bacilliredoxin AbxC Plays a Role in Responding to Oxidative Stress in Radiation-Resistant Bacterium Deinococcus radiodurans

Author: Min-Kyu Kim, Sangryeol Ryu, Jong-Hyun Jung, Laurence Blanchard, Sangyong Lim, Arjan de Groot, Yong Sun Bahn, Soyoung Jeong, Korea Atomic Energy Research Institute [Daejeon, south Korea] (KAERI), Seoul National University [Seoul] (SNU), Microbiologie Environnementale et Moléculaire (MEM), 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), Yonsei University, University of Science and Technology [Daejeon] (UST), 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: 0301 basic medicine, Physiology, [SDV]Life Sciences [q-bio], 030106 microbiology, Clinical Biochemistry, Mutant, RM1-950, Biochemistry, 03 medical and health sciences, chemistry.chemical_compound, Deinococcus radiodurans, DR_1832, oxidative stress, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Molecular Biology, Amino acid synthesis, chemistry.chemical_classification, Reactive oxygen species, biology, bacillithiol, Cell Biology, biology.organism_classification, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, bacilliredoxin, 030104 developmental biology, Enzyme, chemistry, Bacillithiol, biology.protein, Therapeutics. Pharmacology, Nicotinamide adenine dinucleotide phosphate, Peroxidase
Abstract: Deinococcus radiodurans is a robust bacterium with extraordinary resistance to ionizing radiation and reactive oxygen species (ROS). D. radiodurans produces an antioxidant thiol compound called bacillithiol (BSH), but BSH-related enzymes have not been investigated. The D. radiodurans mutant lacking bshA (dr_1555), the first gene of the BSH biosynthetic pathway, was devoid of BSH and sensitive to hydrogen peroxide (H2O2) compared to the wild-type D. radiodurans strain. Three bacilliredoxin (Brx) proteins, BrxA, B, and C, have been identified in BSH-producing bacteria, such as Bacillus. D. radiodurans possesses DR_1832, a putative homolog of BrxC. However, because DR_1832 contains a novel signature motif (TCHKT) and a C-terminal region similar to the colicin-like immunity domain, we named it AbxC (atypical BrxC). The deletion of abxC also sensitized cells to H2O2. AbxC exhibited peroxidase activity in vitro, which was linked to nicotinamide adenine dinucleotide phosphate (NADPH) oxidation via the BSH disulfide reductase DR_2623 (DrBdr). AbxC proteins were present mainly as dimers after exposure to H2O2 in vitro, and the oxidized dimers were resolved to monomers by the reaction coupled with BSH as an electron donor, in which DrBdr transported reducing equivalents from NADPH to AbxC through BSH recycling. We identified 25 D. radiodurans proteins that potentially interact with AbxC using AbxC-affinity chromatography. Most of them are associated with cellular metabolisms, such as glycolysis and amino acid biosynthesis, and stress response. Interestingly, AbxC could bind to the proposed peroxide-sensing transcription regulator, DrOxyR. These results suggest that AbxC may be involved in the H2O2 signaling mechanism mediated by DrOxyR.
Published: 2021
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19. Mycotoxines majeures et émergentes dans les filières cidre et vin : observatoire, lutte biologique au champ et devenir au cours des procédés

Author: Coarer, Morvan, Puel, Olivier, Lorber, Sophie, Guichard, H., Lemaguet, Jean, Corroyer, Nathalie, Camponovo, A., Boiry, Séverine, Sabaty, M., Maguet, Le, Caboulet, Denis, Solanet, D., Institut Français de la Vigne et du Vin (IFV), Biosynthèse & Toxicité des Mycotoxines (ToxAlim-BioToMyc), ToxAlim (ToxAlim), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Ecole Nationale Vétérinaire de Toulouse (ENVT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Ecole d'Ingénieurs de Purpan (INP - PURPAN), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Insitut Français des Productions Cidricoles (IFPC), Comité Interprofessionnel du Vin de Champagne (CIVC), Chambre Régionale d'Agriculture de Normandie, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), and Casdar
Subjects: [SDV.SA]Life Sciences [q-bio]/Agricultural sciences, deoxypatulinic acid, marquage, [SDV]Life Sciences [q-bio], Ochratoxin A, antagonist, patuline, acide désoxypatulinique Ochratoxin A, antagoniste, acide désoxypatulinique, Ochratoxine A, [SDE]Environmental Sciences, patulin, ascladiol, labeling
Abstract: Ce volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche technologique" de 2015. Il a été réalisé sous l’égide du GIS Relance Agronomique. Ce volume regroupe les textes issus du programme Casdar "Innovation et Partenariat" et "Recherche technologique" de 2015. Il a été réalisé sous l’égide du GIS Relance Agronomique.; 3500 samples of fungal flora were studied for their diversity and their potential to antagonizemycotoxinogenic flora. 45 were characterized with respect to their ability to inhibit in vitro the growth ofPenicillium expansum and Aspergillus carbonarius as well as the production of patulin and ochratoxin A.The most promising strains were tested as antagonists in organic and conventional vineyards andorchards as well as in production with varying degrees of success. Following this program, the ciderindustry has a patulin labeling method with 13C. The cytotoxicity tests carried out on ascladiol anddeoxypatulinic acid showed their absence of toxicity. Finally, the two sectors have screening methods toquickly set up additional experiments in the event of natural contamination linked to changes in climateand practices.; 3500 échantillons de flores fongiques ont été étudiés d’après leur diversité et leur potentiel antagonistevis-à-vis des flores mycotoxinogènes. 45 ont été caractérisées vis à vis leur capacité à inhiber in vitro lacroissance de Penicillium expansum et d’Aspergillus carbonarius ainsi que la production de patuline etd’ochratoxine A. Les souches les plus prometteuses ont été testées comme antagonistes au vignoble etau verger bio et conventionnel ainsi qu’en élaboration avec différents degrés de réussite. La filière cidredispose, à la suite de ce programme, d’une méthode de marquage de la patuline au 13C. Les tests decytotoxicité menés sur l’ascladiol et l’acide desoxypatulinique ont montré leur absence de toxicité. Enfin,les deux filières disposent de méthodes de criblage pour mettre rapidement en œuvre desexpérimentations complémentaires en cas de contamination naturelle liée aux évolutions du climat etdes pratiques.
Published: 2021
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20. Magnetospirillum gryphiswaldense

Author: Christopher T. Lefèvre, Caroline L. Monteil, Dirk Schüler, Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), 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), ANR-18-CE31-0003,SIGMAG,SIGNATURE DES MAGNETITES PRODUITES PAR LES BACTERIES MAGNETOTACTIQUES : PERSPECTIVES CHIMIQUES ET ISOTOPIQUES(2018), and ANR-19-CE01-0005,PHOSTORE,Piégeage du phosphore : contribution des bactéries magnétotactiques dans les zones de transition oxique-anoxique(2019)
Subjects: Microbiology (medical), 0303 health sciences, magnetite, 030306 microbiology, Iron, [SDV]Life Sciences [q-bio], Biology, magnetotaxis, biomineralization, Microbiology, Ferrosoferric Oxide, 03 medical and health sciences, Infectious Diseases, Bacterial Proteins, Virology, [SDE]Environmental Sciences, Magnetospirillum gryphiswaldense, Magnetosomes, Magnetospirillum, magnetosome, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology
Abstract: International audience
Published: 2020
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21. Magnetite-Arginine Nanoparticles as a Multifunctional Biomedical Tool

Author: Alexander Kraupner, Klaas Bente, Iwona Cicha, Victoria Reichel, Tobias Heil, Damien Faivre, Silvio Dutz, Jasmin Matuszak, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Matière et Systèmes Complexes (MSC), Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Technische Universität Ilmenau (TU ), Microbiologie Environnementale et Moléculaire (MEM), 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)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Heating power, iron oxide, theranostics, Materials science, Arginine, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, General Chemical Engineering, Iron oxide, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Article, lcsh:Chemistry, chemistry.chemical_compound, Magnetic particle imaging, General Materials Science, ddc:610, Magnetite, nanoparticle, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, hyperthermia, 3. Good health, 0104 chemical sciences, Membrane, [SDV.SP.PG]Life Sciences [q-bio]/Pharmaceutical sciences/Galenic pharmacology, chemistry, lcsh:QD1-999, 0210 nano-technology, Iron oxide nanoparticles, MRI
Abstract: Iron oxide nanoparticles are a promising platform for biomedical applications, both in terms of diagnostics and therapeutics. In addition, arginine-rich polypeptides are known to penetrate across cell membranes. Here, we thus introduce a system based on magnetite nanoparticles and the polypeptide poly-l-arginine (polyR-Fe3O4). We show that the hybrid nanoparticles exhibit a low cytotoxicity that is comparable to Resovist&reg, a commercially available drug. PolyR-Fe3O4 particles perform very well in diagnostic applications, such as magnetic particle imaging (1.7 and 1.35 higher signal respectively for the 3rd and 11th harmonic when compared to Resovist&reg, ), or as contrast agents for magnetic resonance imaging (R2/R1 ratio of 17 as compared to 11 at 0.94 T for Resovist&reg, ). Moreover, these novel particles can also be used for therapeutic purposes such as hyperthermia, achieving a specific heating power ratio of 208 W/g as compared to 83 W/g for Feridex&reg, another commercially available product. Therefore, we envision such materials to play a role in the future theranostic applications, where the arginine ability to deliver cargo into the cell can be coupled to the magnetite imaging properties and cancer fighting activity.
Published: 2020
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22. Synthesis of Two Epimers of Pseudopaline

Author: Cullia, Gregorio, Fanelli, Roberto, Voulhoux, Romé, Arnoux, Pascal, Cavelier, Florine, Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), Association Vaincre la Mucoviscidose (VLM) RFI20160501495, Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), 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: Natural products, [CHIM.ORGA]Chemical Sciences/Organic chemistry, [SDV]Life Sciences [q-bio], Amino acids, Pseudopaline, Total synthesis, Opines, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Opines are a known group of compounds characterized by an elevated polarity. Recently, two new members of this class, staphylopine and pseudopaline, have been identified inStaphylococcus aureusandPseudomonas aeruginosa, respectively. These molecules are metal chelators that contribute to the growth of bacteria in particularly metal-poor environment. Different evidences suggest that these molecules might have an important role in the development of pulmonary infections in humans. Considering the impact ofP. aeruginosainfections in cystic fibrosis patients (prevalence up to 70 %), pseudopaline has risen interest as potential source of new therapeutic intervention. We present herein a straightforward synthetic approach for the synthesis of the two epimers of pseudopaline. Starting from a chiral building block, we attribute the absolute configuration to the two obtained diasteroisomers.
Published: 2020
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23. Repeated horizontal gene transfers triggered parallel evolution of magnetotaxis in two evolutionary divergent lineages of magnetotactic bacteria

Author: Christopher T. Lefèvre, Caroline L. Monteil, Béatrice Alonso, Denis S. Grouzdev, Zoé Rouy, Stéphane Cruveiller, David Pignol, Nicolas Ginet, Guy Perrière, 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), Centre National de la Recherche Scientifique (CNRS), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Microbiologie Environnementale et Moléculaire (MEM), 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)), ANR-18-CE31-0003,SIGMAG,SIGNATURE DES MAGNETITES PRODUITES PAR LES BACTERIES MAGNETOTACTIQUES : PERSPECTIVES CHIMIQUES ET ISOTOPIQUES(2018), 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: Gene Transfer, Horizontal, Magnetotactic bacteria, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, Microbiology, Article, 03 medical and health sciences, Phylogenetics, Gram-Negative Bacteria, Magnetotaxis, Magnetospirillum, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, Alphaproteobacteria, 030304 developmental biology, 0303 health sciences, Experimental evolution, Bacteria, biology, 030306 microbiology, Clonal interference, [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE], biology.organism_classification, Evolutionary biology, Parallel evolution, Adaptation
Abstract: Under the same selection pressures, two genetically divergent populations may evolve in parallel toward the same adaptive solutions. Here, we hypothesized that magnetotaxis (i.e., magnetically guided chemotaxis) represents a key adaptation to micro-oxic habitats in aquatic sediments and that its parallel evolution homogenized the phenotypes of two evolutionary divergent clusters of freshwater spirilla. All magnetotactic bacteria affiliated to the Magnetospirillum genus (Alphaproteobacteria class) biomineralize the same magnetic particle chains and share highly similar physiological and ultrastructural features. We looked for the processes that could have contributed at shaping such an evolutionary pattern by reconciling species and gene trees using newly sequenced genomes of Magnetospirillum related bacteria. We showed that repeated horizontal gene transfers and homologous recombination of entire operons contributed to the parallel evolution of magnetotaxis. We propose that such processes could represent a more parsimonious and rapid solution for adaptation compared with independent and repeated de novo mutations, especially in the case of traits as complex as magnetotaxis involving tens of interacting proteins. Besides strengthening the idea about the importance of such a function in micro-oxic habitats, these results reinforce previous observations in experimental evolution suggesting that gene flow could alleviate clonal interference and speed up adaptation under some circumstances.
Published: 2020
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24. High-speed motility originates from cooperatively pushing and pulling flagella bundles in bilophotrichous bacteria

Author: Christopher T. Lefèvre, Sarah Mohammadinejad, Agnese Codutti, Felix Bachmann, Klaas Bente, Damien Faivre, Mohammad A. Charsooghi, Stefan Klumpp, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Institute for Advanced Studies in Basic Sciences [Zanjan] (IASBS), Georg-August-University = Georg-August-Universität Göttingen, Microbiologie Environnementale et Moléculaire (MEM), 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), ANR-16-TERC-0025,BIOMAGNET,Exploration de la biodiversité des bactéries magnétotactiques(2016), Bente, Klaas [0000-0002-2520-4697], Mohammadinejad, Sarah [0000-0002-3758-5693], Charsooghi, Mohammad Avalin [0000-0002-7772-8513], Klumpp, Stefan [0000-0003-0584-2146], Faivre, Damien [0000-0001-6191-3389], Apollo - University of Cambridge Repository, Georg-August-University [Göttingen], 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: 0301 basic medicine, Rotation, Magnetotactic bacteria, QH301-705.5, Science, Movement, [SDV]Life Sciences [q-bio], 030106 microbiology, Path tracking, Motility, Flagellum, Physics of Living Systems, Models, Biological, General Biochemistry, Genetics and Molecular Biology, Magnetococcus marinus, 03 medical and health sciences, Magnetotactic cocci, Biology (General), 030304 developmental biology, Alphaproteobacteria, Physics, 0303 health sciences, General Immunology and Microbiology, biology, 030306 microbiology, General Neuroscience, magnetotactic bacteria, microswimmer, General Medicine, biology.organism_classification, dark-field microscopy, 030104 developmental biology, Flagella, Bundle, path tracking, Hydrodynamics, Biophysics, Medicine, Other, Bacteria, Research Article
Abstract: Funder: Max-Planck-Gesellschaft; FundRef: http://dx.doi.org/10.13039/501100004189, Funder: IMPRS on Multiscale Biosystems, Funder: French National Research Agency; FundRef: http://dx.doi.org/10.13039/501100001665; Grant(s): ANR Tremplin-ERC: ANR-16-TERC-0025-01, Bacteria propel and change direction by rotating long, helical filaments, called flagella. The number of flagella, their arrangement on the cell body and their sense of rotation hypothetically determine the locomotion characteristics of a species. The movement of the most rapid microorganisms has in particular remained unexplored because of additional experimental limitations. We show that magnetotactic cocci with two flagella bundles on one pole swim faster than 500 µm·s-1 along a double helical path, making them one of the fastest natural microswimmers. We additionally reveal that the cells reorient in less than 5 ms, an order of magnitude faster than reported so far for any other bacteria. Using hydrodynamic modeling, we demonstrate that a mode where a pushing and a pulling bundle cooperate is the only possibility to enable both helical tracks and fast reorientations. The advantage of sheathed flagella bundles is the high rigidity, making high swimming speeds possible.
Published: 2020
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25. Transformation Cycle of Magnetosomes in Human Stem Cells: From Degradation to Biosynthesis of Magnetic Nanoparticles Anew

Author: Christine Péchoux, Claire Wilhelm, Sandra Prévéral, Christopher T. Lefèvre, Aurore Van de Walle, David Pignol, Nicolas Menguy, Aida Serrano, Alberto Curcio, Ana Espinosa, Matière et Systèmes Complexes (MSC), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), CSIC, Inst Ciencia Mat Madrid, Cantoblanco, E-28049 Madrid, Spain, 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), Unité de recherche génomique et physiologie de la lactation (GPL), Institut National de la Recherche Agronomique (INRA), Génétique Animale et Biologie Intégrative (GABI), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Paris-Saclay, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Microbiologie Environnementale et Moléculaire (MEM), 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)), Comunidad de Madrid 2018-T1/1ND-100S, European Project: 648779,H2020,ERC-2014-CoG,MaTissE(2015), Matière et Systèmes Complexes (MSC (UMR_7057)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), 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), Université Paris-Saclay-AgroParisTech-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)
Subjects: magnetite, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, Magnetotactic bacteria, Surface Properties, Magnetism, Magnetosome, General Physics and Astronomy, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, magnetosomes, biodegradation, ferrihydrite, chemistry.chemical_compound, Ferrihydrite, Humans, General Materials Science, Particle Size, Magnetite Nanoparticles, Lipid bilayer, Cells, Cultured, Magnetite, Chemistry, General Engineering, Mesenchymal Stem Cells, 021001 nanoscience & nanotechnology, equipment and supplies, 0104 chemical sciences, Biophysics, Magnetic nanoparticles, nanoparticles, biosynthesis, 0210 nano-technology
Abstract: International audience; The nanoparticles produced by magnetotactic bacteria, called magnetosomes, are made of a magnetite core with high levels of crystallinity surrounded by a lipid bilayer. This organized structure has been developed during the course of evolution of these organisms to adapt to their specific habitat and is assumed to resist degradation and to be able to withstand the demanding biological environment. Herein, we investigated magnetosomes' structural fate upon internalization in human stem cells using magnetic and photothermal measurements, electron microscopy, and X-ray absorption spectroscopy. All measurements first converge to the demonstration that intracellular magnetosomes can experience an important biodegradation, with up to 70% of their initial content degraded, which is associated with the progressive storage of the released iron in the ferritin protein. It correlates with an extensive magnetite to ferrihydrite phase transition. The ionic species delivered by this degradation could then be used by the cells to biosynthesize magnetic nanoparticles anew. In this case, cell magnetism first decreased with magnetosomes being dissolved, but then cells remagnetized entirely, evidencing the neo-synthesis of biogenic magnetic nanoparticles. Bacteria-made biogenic magnetosomes can thus be totally remodeled by human stem cells, into human cells-made magnetic nanoparticles.
Published: 2020
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26. Complete Genome Sequence of Strain BW-2, a Magnetotactic Gammaproteobacterium in the Family Ectothiorhodospiraceae , Isolated from a Brackish Spring in Death Valley, California

Author: Dennis A. Bazylinski, Christopher T. Lefèvre, Viviana Morillo-Lopez, Fernanda Abreu, Caroline L. Monteil, Corey Geurink, Denis Trubitsyn, University of Nevada [Las Vegas] (WGU Nevada), Microbiologie Environnementale et Moléculaire (MEM), 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), Universidade Federal do Rio de Janeiro (UFRJ), Longwood University [Farmville], U.S. NSF grant EAR-1423939., 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: Genetics, Whole genome sequencing, 0303 health sciences, Class Gammaproteobacteria, Strain (chemistry), Magnetotactic bacteria, 030306 microbiology, [SDV]Life Sciences [q-bio], Genome Sequences, Magnetosome, Biology, 03 medical and health sciences, Immunology and Microbiology (miscellaneous), Magnetotaxis, Molecular Biology, 030304 developmental biology, Biomineralization, FAMILY ECTOTHIORHODOSPIRACEAE
Abstract: We report the complete 4.1-Mb genome sequence of strain BW-2, a magnetotactic, sulfur-oxidizing rod, belonging to the family Ectothiorhodospiraceae of the class Gammaproteobacteria, that biomineralizes membrane-bounded magnetite nanocrystals in its magnetosomes. This genome sequence, in comparison with those of other magnetotactic bacteria, is essential for understanding the origin and evolution of magnetotaxis and magnetosome biomineralization.
Published: 2020
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27. From conservation to structure, studies of magnetosome associated cation diffusion facilitators (CDF) proteins in Proteobacteria

Author: Caroline L. Monteil, Nitzan Kutnowski, N. Zeytuni, Raz Zarivach, Noa Keren-Khadmy, Guy Perrière, Ben-Gurion University of the Negev (BGU), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Biomineralization, Deltaproteobacteria, Models, Molecular, Protein Conformation, Physical Chemistry, Conserved sequence, Materials, Conserved Sequence, Phylogeny, Data Management, Genetics, 0303 health sciences, Minerals, Multidisciplinary, Crystallography, biology, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Physics, 030302 biochemistry & molecular biology, Monomers, Phylogenetic Analysis, Condensed Matter Physics, Mineralogy, Phylogenetics, Actinobacteria, Chemistry, Physical Sciences, Crystal Structure, Medicine, Proteobacteria, Dimerization, Cation diffusion facilitator, Research Article, Computer and Information Sciences, Magnetotactic bacteria, Science, Magnetosome, Materials Science, Sequence alignment, Magnetite, 03 medical and health sciences, Bacterial Proteins, Cations, Solid State Physics, Evolutionary Systematics, Amino Acid Sequence, Dimers, 030304 developmental biology, Alphaproteobacteria, Taxonomy, Evolutionary Biology, Ion Transport, Bacteria, Organisms, Biology and Life Sciences, biology.organism_classification, Polymer Chemistry, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Chemical Properties, Oligomers, Earth Sciences, Magnetosomes, Carrier Proteins, Sequence Alignment, Mycobacterium Tuberculosis
Abstract: International audience; Magnetotactic bacteria (MTB) are prokaryotes that sense the geomagnetic field lines to geo-locate and navigate in aquatic sediments. They are polyphyletically distributed in several bacterial divisions but are mainly represented in the Proteobacteria. In this phylum, magne-totactic Deltaproteobacteria represent the most ancestral class of MTB. Like all MTB, they synthesize membrane-enclosed magnetic nanoparticles, called magnetosomes, for magnetic sensing. Magnetosome biogenesis is a complex process involving a specific set of genes that are conserved across MTB. Two of the most conserved genes are mamB and mamM, that encode for the magnetosome-associated proteins and are homologous to the cation diffusion facilitator (CDF) protein family. In magnetotactic Alphaproteobacteria MTB species, MamB and MamM proteins have been well characterized and play a central role in iron-transport required for biomineralization. However, their structural conservation and their role in more ancestral groups of MTB like the Deltaproteobacteria have not been established. Here we studied magnetite cluster MamB and MamM cytosolic C-terminal domain (CTD) structures from a phylogenetically distant magnetotactic Deltaproteobacteria species represented by BW-1 strain, which has the unique ability to biomineralize magnetite and greigite. We characterized them in solution, analyzed their crystal structures and compared them to those characterized in Alphaproteobacteria MTB species. We showed that despite the high phylogenetic distance, MamB BW-1 and MamM BW-1 CTDs share high structural similarity with known CDF-CTDs and will probably share a common function with the Alphapro-teobacteria MamB and MamM.
Published: 2020
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28. Self-Confined Nucleation of Iron Oxide Nanoparticles in a Nanostructured Amorphous Precursor

Author: Raj Kumar Ramamoorthy, Mathieu Bennet, Damien Faivre, Marie-Alexandra Neouze, Alexy P. Freitas, David Carriere, Jens Baumgartner, Department of Biomaterials [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), DFG-ANR FA 835/10-1, ANR-14-CE08-0003,DIAMONS,Phases denses intermédiaires liquides et amorphes comme modèle alternatif pour la synthèse de nanoparticules d'oxydes(2014), ANR-10-LABX-0035,Nano-Saclay,Paris-Saclay multidisciplinary Nano-Lab(2010), European Project: 256915,EC:FP7:ERC,ERC-2010-StG_20091028,MB2(2011), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Nanostructure, Materials science, Mechanical Engineering, Nucleation, Nanoparticle, Bioengineering, Crystal growth, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, law.invention, Amorphous solid, Crystal, law, Chemical physics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Classical nucleation theory, Crystallization, 0210 nano-technology
Abstract: International audience; Crystallization from solution is commonly described by classical nucleation theory, although this ignores that crystals often form via disordered nanostructures. As an alternative, the classical theory remains widely used in a “multi-step” variant, where the intermediate nanostructures merely introduce additional thermodynamic parameters. But this variant still requires validation by experiments addressing indeed proper time and spatial scales (ms, nm). Here, we used in situ X-ray scattering to determine the mechanism of magnetite crystallization and in particular how nucleation propagates at the nanometer scale within amorphous precursors. We find that the self-confinement by an amorphous precursor slows down crystal growth by two orders of magnitude once the crystal size reaches the amorphous particle size (c.a. 3 nm). Thus, not only the thermodynamic properties of transient amorphous nanostructures, but also their spatial distribution determine crystal nucleation.
Published: 2020
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29. Conservation and diversity of radiation and oxidative stress resistance mechanisms inDeinococcusspecies

Author: Sangyong Lim, Jong-Hyun Jung, Arjan de Groot, Laurence Blanchard, Korea Atomic Energy Research Institute, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), 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: DNA damage, DNA repair, [SDV]Life Sciences [q-bio], Review Article, Biology, Microbiology, 03 medical and health sciences, chemistry.chemical_compound, Species Specificity, Stress, Physiological, DNA Repair Protein, Deinococcus, regulatory proteins, Gene, ComputingMilieux_MISCELLANEOUS, biodiversity, 030304 developmental biology, Genetics, 0303 health sciences, 030306 microbiology, oxidative damage protection, Deinococcus radiodurans, stress response, biology.organism_classification, metal homeostatis, Oxidative Stress, Infectious Diseases, Regulon, chemistry, bacteria, DNA
Abstract: Deinococcus bacteria are famous for their extreme resistance to ionising radiation and other DNA damage- and oxidative stress-generating agents. More than a hundred genes have been reported to contribute to resistance to radiation, desiccation and/or oxidative stress in Deinococcus radiodurans. These encode proteins involved in DNA repair, oxidative stress defence, regulation and proteins of yet unknown function or with an extracytoplasmic location. Here, we analysed the conservation of radiation resistance-associated proteins in other radiation-resistant Deinococcus species. Strikingly, homologues of dozens of these proteins are absent in one or more Deinococcus species. For example, only a few Deinococcus-specific proteins and radiation resistance-associated regulatory proteins are present in each Deinococcus, notably the metallopeptidase/repressor pair IrrE/DdrO that controls the radiation/desiccation response regulon. Inversely, some Deinococcus species possess proteins that D. radiodurans lacks, including DNA repair proteins consisting of novel domain combinations, translesion polymerases, additional metalloregulators, redox-sensitive regulator SoxR and manganese-containing catalase. Moreover, the comparisons improved the characterisation of several proteins regarding important conserved residues, cellular location and possible protein–protein interactions. This comprehensive analysis indicates not only conservation but also large diversity in the molecular mechanisms involved in radiation resistance even within the Deinococcus genus., The authors reviewed the mechanisms and factors involved in the extreme radiation and oxidative stress resistance in Deinococcus radiodurans in comparison with 10 other resistant Deinococcus species, and highlighted not only conserved pathways but also a large diversity of the repair, protection and regulation toolbox among the different deinococci.
Published: 2018
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30. Magnetotactic bacteria as a new model for P sequestration in the ferruginous Lake Pavin

Author: Fériel Skouri-Panet, François Guyot, N. Trcera, Didier Jézéquel, Christopher T. Lefèvre, Caroline L. Monteil, Karim Benzerara, Nicolas Menguy, Elodie Duprat, Eric Viollier, Mélanie Poinsot, Jennyfer Miot, Céline Férard, S. Rivas-Lamelo, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Biologie végétale et microbiologie environnementale - UMR7265 (BVME), 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), Microbiologie Environnementale et Moléculaire (MEM), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), ANR-14-CE33-0003,SRB,Sulfato-Réduction Bactérienne: mécanismes de biominéralisation et préservation de biosignatures d'un métabolisme phare de l'histoire de la Terre(2014), European Project: 307110,EC:FP7:ERC,ERC-2012-StG_20111012,CALCYAN(2013), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-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), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: food.ingredient, 010504 meteorology & atmospheric sciences, Magnetotactic bacteria, Microorganism, Context (language use), Beggiatoa, 01 natural sciences, Geochemical cycle, 03 medical and health sciences, food, Water column, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Geochemistry and Petrology, Environmental Chemistry, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 030304 developmental biology, 0105 earth and related environmental sciences, 0303 health sciences, biology, Ecology, Chemistry, Geology, biology.organism_classification, 6. Clean water, Enhanced biological phosphorus removal, Environmental chemistry, Thiomargarita
Abstract: International audience; The role of microorganisms in the geochemical cycle of P has received great interest in the context of enhanced biological phosphorus removal and phosphorite formation. Here, we combine scanning and transmission electron microscopies, confocal laser scanning microscopy and synchrotron-based x-ray microfluorescence to analyse the distribution of P at the oxic-anoxic interface in the water column of the ferruginous Lake Pavin. We show that magnetotactic bacteria of the Magnetococca-ceae family strongly accumulate polyphosphates and appear as P hotspots in the particulate fraction at this depth. This high accumulation may be characteristic of this family and may also relate to the chemical conditions prevailing in the lake. As a result, these magneto-tactic cocci can be considered as new models playing a potentially important role in the P geochemical cycle, similar to sulphide oxidising bacteria such as Thiomargarita and Beggiatoa but thriving in a ferruginous, poorly sulphidic environment.
Published: 2017
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31. Ice nucleation active bacteria in precipitation are genetically diverse and nucleate ice by employing different mechanisms

Author: Caroline L. Monteil, Kevin Failor, D G Schmale rd, Boris A. Vinatzer, Department of Plant Pathology, Physiology, and Weed Science [Blacksburg] (PPPWS), Virginia Tech [Blacksburg], Station de Pathologie Végétale (AVI-PATHO), Institut National de la Recherche Agronomique (INRA), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-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)-Aix Marseille Université (AMU)-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), National Science Foundation under grant DEB-1241068, Virginia Agricultural Experiment Station, Hatch Program of the National Institute of Food and Agriculture, US Department of Agriculture, Unité de Pathologie Végétale (PV), 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)), 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: 0301 basic medicine, concentration, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Air Microbiology, Nucleation, 01 natural sciences, Microbiology, 03 medical and health sciences, Freezing, ice nucleating bacteria, Phylogeny, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Lysinibacillus, Bacteria, précipitation, biology, Precipitation (chemistry), Ice, Xanthomonadaceae, Genetic Variation, Water, biology.organism_classification, rôle vecteur, Enterobacteriaceae, genêtic variation, 030104 developmental biology, 13. Climate action, diversité génétique, Environmental chemistry, Ice nucleus, Original Article, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, bactérie glacogène, human activities, Pseudomonadaceae
Abstract: A growing body of circumstantial evidence suggests that ice nucleation active (Ice(+)) bacteria contribute to the initiation of precipitation by heterologous freezing of super-cooled water in clouds. However, little is known about the concentration of Ice(+) bacteria in precipitation, their genetic and phenotypic diversity, and their relationship to air mass trajectories and precipitation chemistry. In this study, 23 precipitation events were collected over 15 months in Virginia, USA. Air mass trajectories and water chemistry were determined and 33 134 isolates were screened for ice nucleation activity (INA) at -8 °C. Of 1144 isolates that tested positive during initial screening, 593 had confirmed INA at -8 °C in repeated tests. Concentrations of Ice(+) strains in precipitation were found to range from 0 to 13 219 colony forming units per liter, with a mean of 384±147. Most Ice(+) bacteria were identified as members of known and unknown Ice(+) species in the Pseudomonadaceae, Enterobacteriaceae and Xanthomonadaceae families, which nucleate ice employing the well-characterized membrane-bound INA protein. Two Ice(+) strains, however, were identified as Lysinibacillus, a Gram-positive genus not previously known to include Ice(+) bacteria. INA of the Lysinibacillus strains is due to a nanometer-sized molecule that is heat resistant, lysozyme and proteinase resistant, and secreted. Ice(+) bacteria and the INA mechanisms they employ are thus more diverse than expected. We discuss to what extent the concentration of culturable Ice(+) bacteria in precipitation and the identification of a new heat-resistant biological INA mechanism support a role for Ice(+) bacteria in the initiation of precipitation.
Published: 2017
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32. Chemotaxis in external fields: Simulations for active magnetic biological matter

Author: Damien Faivre, Agnese Codutti, Klaas Bente, Stefan Klumpp, Department of Biomaterials [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Department of Theory and Bio-Systems [Potsdam], Microbiologie Environnementale et Moléculaire (MEM), 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), Department of Nonlinear Dynamics [Göttingen], Max Planck Institute for Dynamics and Self-Organization (MPIDS), 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: 0301 basic medicine, Physiology, [SDV]Life Sciences [q-bio], Velocity, Quantitative Biology::Cell Behavior, 0302 clinical medicine, Fluid dynamics, Medicine and Health Sciences, Biology (General), Brownian motion, Physics, Physics::Biological Physics, Ecology, Magnetic moment, Chemotaxis, Simulation and Modeling, Magnetism, Classical Mechanics, Mechanics, Condensed Matter Physics, Magnetic field, Cell Motility, Chemistry, Computational Theory and Mathematics, Modeling and Simulation, Physical Sciences, Research Article, Chemical Elements, Magnetic fields, Oxygen, Swimming, Motion, Torque, Simulation and modeling, Magnetotactic bacteria, QH301-705.5, Movement, Bacterial Physiological Phenomena, Research and Analysis Methods, Models, Biological, Quantitative Biology::Subcellular Processes, 03 medical and health sciences, Cellular and Molecular Neuroscience, Magnetics, ddc:570, Genetics, Escherichia coli, Computer Simulation, Magnetospirillum, Molecular Biology, Ecology, Evolution, Behavior and Systematics, Biological Locomotion, Computational Biology, Biology and Life Sciences, Institut für Physik und Astronomie, Cell Biology, equipment and supplies, 030104 developmental biology, Magnetic Fields, Magnet, human activities, 030217 neurology & neurosurgery
Abstract: The movement of microswimmers is often described by active Brownian particle models. Here we introduce a variant of these models with several internal states of the swimmer to describe stochastic strategies for directional swimming such as run and tumble or run and reverse that are used by microorganisms for chemotaxis. The model includes a mechanism to generate a directional bias for chemotaxis and interactions with external fields (e.g., gravity, magnetic field, fluid flow) that impose forces or torques on the swimmer. We show how this modified model can be applied to various scenarios: First, the run and tumble motion of E. coli is used to establish a paradigm for chemotaxis and investigate how it is affected by external forces. Then, we study magneto-aerotaxis in magnetotactic bacteria, which is biased not only by an oxygen gradient towards a preferred concentration, but also by magnetic fields, which exert a torque on an intracellular chain of magnets. We study the competition of magnetic alignment with active reorientation and show that the magnetic orientation can improve chemotaxis and thereby provide an advantage to the bacteria, even at rather large inclination angles of the magnetic field relative to the oxygen gradient, a case reminiscent of what is expected for the bacteria at or close to the equator. The highest gain in chemotactic velocity is obtained for run and tumble with a magnetic field parallel to the gradient, but in general a mechanism for reverse motion is necessary to swim against the magnetic field and a run and reverse strategy is more advantageous in the presence of a magnetic torque. This finding is consistent with observations that the dominant mode of directional changes in magnetotactic bacteria is reversal rather than tumbles. Moreover, it provides guidance for the design of future magnetic biohybrid swimmers., Author summary In this paper, we propose a modified Active Brownian particle model to describe bacterial swimming behavior under the influence of external forces and torques, in particular of a magnetic torque. This type of interaction is particularly important for magnetic biohybrids (i.e. motile bacteria coupled to a synthetic magnetic component) and for magnetotactic bacteria (i.e. bacteria with a natural intracellular magnetic chain), which perform chemotaxis to swim along chemical gradients, but are also directed by an external magnetic field. The model allows us to investigate the benefits and disadvantages of such coupling between two different directionality mechanisms. In particular we show that the magnetic torque can speed chemotaxis up in some conditions, while it can hinder it in other cases. In addition to an understanding of the swimming strategies of naturally magnetotactic organisms, the results may guide the design of future biomedical devices.
Published: 2019
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33. Biologically encoded magnonics

Author: Zingsem, Benjamin, Feggeler, Thomas, Terwey, Alexandra, Ghaisari, Sara, Spoddig, Detlef, Faivre, Damien, Meckenstock, Ralf, Farle, Michael, Winklhofer, Michael, Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen [Essen], Ernst Ruska Center for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Ludwig-Maximilians-Universität München (LMU), European Project: 320832,EC:FP7:ERC,ERC-2012-ADG_20120216,IMAGINE(2013), European Project: 256915,EC:FP7:ERC,ERC-2010-StG_20091028,MB2(2011), Universität Duisburg-Essen = University of Duisburg-Essen [Essen], Ernst Ruska-Zentrum für Mikroskopie und Spektroskopie mit Elektronen (ER-C), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Biomineralization, Genotype, Science, [SDV]Life Sciences [q-bio], Article, Quantitative Biology::Cell Behavior, Applied microbiology, Magnetics, Condensed Matter::Materials Science, Computer Simulation, Magnetospirillum, Particle Size, lcsh:Science, Condensed Matter::Other, Physics, Magnetic devices, Physik (inkl. Astronomie), Life sciences, biology, Mutation, Anisotropy, Nanoparticles, Quantum Theory, lcsh:Q, Spin Labels, Condensed Matter::Strongly Correlated Electrons, Magnetosomes, Crystallization
Abstract: Spin wave logic circuits using quantum oscillations of spins (magnons) as carriers of information have been proposed for next generation computing with reduced energy demands and the benefit of easy parallelization. Current realizations of magnonic devices have micrometer sized patterns. Here we demonstrate the feasibility of biogenic nanoparticle chains as the first step to truly nanoscale magnonics at room temperature. Our measurements on magnetosome chains (ca 12 magnetite crystals with 35 nm particle size each), combined with micromagnetic simulations, show that the topology of the magnon bands, namely anisotropy, band deformation, and band gaps are determined by local arrangement and orientation of particles, which in turn depends on the genotype of the bacteria. Our biomagnonic approach offers the exciting prospect of genetically engineering magnonic quantum states in nanoconfined geometries. By connecting mutants of magnetotactic bacteria with different arrangements of magnetite crystals, novel architectures for magnonic computing may be (self-) assembled., The capability to engineer magnon states in confined geometries is vital to future nano-magnonics. Here the authors demonstrate that the topology of the magnon bands is determined by the local arrangement and orientation of nanoparticles and can be controlled by the genotype of magnetotactic bacteria.
Published: 2019
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34. Magnetoreception in Microorganisms

Author: Caroline L. Monteil, Christopher T. Lefèvre, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), ANR-16-TERC-0025,BIOMAGNET,Exploration de la biodiversité des bactéries magnétotactiques(2016), ANR-18-CE31-0003,SIGMAG,SIGNATURE DES MAGNETITES PRODUITES PAR LES BACTERIES MAGNETOTACTIQUES : PERSPECTIVES CHIMIQUES ET ISOTOPIQUES(2018), 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: Microbiology (medical), Magnetotactic bacteria, Microorganism, [SDV]Life Sciences [q-bio], Magnetosome, Biology, Microbiology, magnetosomes, Astrobiology, Magnetics, 03 medical and health sciences, Virology, grazing, grazing 22, 030304 developmental biology, protists, 0303 health sciences, 030306 microbiology, Magnetic Phenomena, Eukaryota, Magnetoreception, magnetotactic bacteria, equipment and supplies, biology.organism_classification, biomineralization, 21 protists, symbiosis, Infectious Diseases, Prokaryotic Cells, magnetoreception, human activities, Bacteria, holobionts, Biomineralization
Abstract: International audience; Magnetoreception is the sense whereby organisms geolocate and navigate in response to the Earth's magnetic field lines. For decades, magnetotactic bacteria have been the only known magnetoreceptive microorganisms. The magnetotactic behaviour of these aquatic prokaryotes is due to the biomineralization of magnetic crystals. While an old report alleged the existence of microbial algae with similar behaviour, recent discoveries have demonstrated the existence of unicellular eukaryotes able to sense the geomagnetic field, and have revealed different mechanisms and strategies involved in such a sensing. Some ciliates can be magnetically guided after predation of magnetotactic bacteria, while some flagellates acquired this sense through symbiosis with magnetic bacteria. A report has even suggested that some magnetotactic protists could biomineralize magnetic crystals.
Published: 2019
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35. Crystal structure of the transcriptional repressor DdrO: insight into the metalloprotease/repressor-controlled radiation response in Deinococcus

Author: Philippe Roche, Fabrice Confalonieri, Pascale Servant, Romaric Magerand, David Lemaire, David Pignol, François Parcy, Pascal Arnoux, Géraldine Brandelet, Raquel Martin-Arevalillo, Laurence Blanchard, Jade Doloy, Nicolas Eugénie, Arjan de Groot, Marina I. Siponen, Renaud Dumas, Microbiologie Environnementale et Moléculaire (MEM), 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), Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Radiorésistance des bactéries et des archées (RBA), Département Biologie des Génomes (DBG), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Régulateurs du développement de la fleur (Flo_RE), 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)-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), Interactions Protéine Métal (IPM), Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC), ANR-19-CE12-0010,NOVOREP,Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), ANR-19-CE12-0010,NOVOREP,Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress(2019), 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), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université Paris-Saclay, Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Cancérologie de Marseille (CRCM), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Aix Marseille Université (AMU), MARAVAL, Alexandra, and Réparation des dommages ou mort cellulaire chez les bactéries exposées aux stress - - NOVOREP2019 - ANR-19-CE12-0010 - AAPG2019 - VALID
Subjects: Models, Molecular, DNA damage, [SDV]Life Sciences [q-bio], Repressor, [SDV.CAN]Life Sciences [q-bio]/Cancer, Cleavage (embryo), Crystallography, X-Ray, DNA-binding protein, Protein Structure, Secondary, 03 medical and health sciences, Protein structure, Structural Biology, Stress, Physiological, [SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology, Genetics, Deinococcus, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Amino Acid Sequence, Peptide sequence, 030304 developmental biology, 0303 health sciences, [SDV.MHEP] Life Sciences [q-bio]/Human health and pathology, biology, 030306 microbiology, Gene Expression Regulation, Bacterial, biology.organism_classification, Protein Structure, Tertiary, [SDV] Life Sciences [q-bio], Repressor Proteins, Biophysics, Metalloproteases, Alpha helix, [SDV.MHEP]Life Sciences [q-bio]/Human health and pathology, DNA Damage, Transcription Factors
Abstract: Exposure to harmful conditions such as radiation and desiccation induce oxidative stress and DNA damage. In radiation-resistant Deinococcus bacteria, the radiation/desiccation response is controlled by two proteins: the XRE family transcriptional repressor DdrO and the COG2856 metalloprotease IrrE. The latter cleaves and inactivates DdrO. Here, we report the biochemical characterization and crystal structure of DdrO, which is the first structure of a XRE protein targeted by a COG2856 protein. DdrO is composed of two domains that fold independently and are separated by a flexible linker. The N-terminal domain corresponds to the DNA-binding domain. The C-terminal domain, containing three alpha helices arranged in a novel fold, is required for DdrO dimerization. Cleavage by IrrE occurs in the loop between the last two helices of DdrO and abolishes dimerization and DNA binding. The cleavage site is hidden in the DdrO dimer structure, indicating that IrrE cleaves DdrO monomers or that the interaction with IrrE induces a structural change rendering accessible the cleavage site. Predicted COG2856/XRE regulatory protein pairs are found in many bacteria, and available data suggest two different molecular mechanisms for stress-induced gene expression: COG2856 protein-mediated cleavage or inhibition of oligomerization without cleavage of the XRE repressor.
Published: 2019
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36. Decoding biomineralization: Interaction of a Mad10-derived peptide with magnetite thin films

Author: Nika Spiridis, Carmen Valverde-Tercedor, Stefan Klumpp, Anna Pohl, K. Freindl, Florian Berger, Damien Faivre, Christopher T. Lefèvre, Nicolas Menguy, Ruby May A. Sullan, Kerstin Blank, Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Rockefeller University [New York], Polish Academy of Sciences (PAN), Microbiologie Environnementale et Moléculaire (MEM), 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), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Nonlinear Dynamics [Göttingen], Max Planck Institute for Dynamics and Self-Organization (MPIDS), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, 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: Deltaproteobacteria, magnetite, Magnetotactic bacteria, [SDV]Life Sciences [q-bio], Bioengineering, Nanotechnology, Peptide, 02 engineering and technology, single-molecule force spectroscopy, Biofouling, chemistry.chemical_compound, Bacterial Proteins, General Materials Science, Amino Acid Sequence, Thin film, Magnetite, chemistry.chemical_classification, Chemistry, Mechanical Engineering, organics−inorganics interaction, magnetotactic bacteria, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, biomineralization, Ferrosoferric Oxide, Magnetosomes, 0210 nano-technology, Peptides, human activities, magnetite-binding peptide, Biomineralization
Abstract: International audience; Protein−surface interactions play a pivotal role in processes as diverse as biomineralization, biofouling, and the cellular response to medical implants. In biomineralization processes, biomacromolecules control mineral deposition and architecture via complex and often unknown mechanisms. For studying these mechanisms, the formation of magnetite nanoparticles in magnetotactic bacteria has become an excellent model system. Most interestingly, nanoparticle morphologies have been discovered that defy crystallographic rules (e.g., in the species $Desulfamplus\ magnetovallimortis$ strain BW-1). In certain conditions, this strain mineralizes bullet-shaped magnetite nanoparticles, which exhibit defined (111) crystal faces and are elongated along the [100] direction. We hypothesize that surface-specific protein interactions break the nanoparticle symmetry, inhibiting the growth of certain crystal faces and thereby favoring the growth of others. Screening the genome of BW-1, we identified Mad10 (Magnetosome-associated deep-branching) as a potential magnetite-binding protein. Using atomic force microscope (AFM)-based single-molecule force spectroscopy, we show that a Mad10-derived peptide, which represents the most conserved region of Mad10, binds strongly to (100)-and (111)-oriented single-crystalline magnetite thin films. The peptide− magnetite interaction is thus material-but not crystal-face-specific. It is characterized by broad rupture force distributions that do not depend on the retraction speed of the AFM cantilever. To account for these experimental findings, we introduce a three-state model that incorporates fast rebinding. The model suggests that the peptide−surface interaction is strong in the absence of load, which is a direct result of this fast rebinding process. Overall, our study sheds light on the kinetic nature of peptide−surface interactions and introduces a new magnetite-binding peptide with potential use as a functional coating for magnetite nanoparticles in biotechnological and biomedical applications.
Published: 2019
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37. Ectosymbiotic bacteria at the origin of magnetoreception in a marine protist

Author: David Vallenet, Eric Viollier, Damien Faivre, Nathalie Leonhardt, Stéphanie Fouteau, Géraldine Adryanczyk, Corinne Cruaud, Christopher T. Lefèvre, Nicolas Menguy, Purificación López-García, David Pignol, Richard J. Weld, Karim Benzerara, Valérie Barbe, Caroline L. Monteil, Magali Floriani, Microbiologie Environnementale et Moléculaire (MEM), 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), Génomique métabolique (UMR 8030), Genoscope - Centre national de séquençage [Evry] (GENOSCOPE), Université Paris-Saclay-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 Paris-Saclay-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 d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'écotoxicologie des radionucléides (IRSN/PSE-ENV/SRTE/LECO), Service de recherche sur les transferts et les effets des radionucléides sur les écosystèmes (IRSN/PSE-ENV/SRTE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Plant Environmental Physiology and Stress Signaling (PEPSS), Department of Biomaterials [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Ecologie Systématique et Evolution (ESE), Université Paris-Sud - Paris 11 (UP11)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Lincoln University, New Zealand, Dumont d’Urville Science and Technology Programme (grant no. DDU-LVL1501), New Zealand Ministry for Business, Innovation and Employment (grant no. LVLX1703), ANR-16-TERC-0025,BIOMAGNET,Exploration de la biodiversité des bactéries magnétotactiques(2016), ANR-14-CE35-0018,GroMa,Greigite or magnetite: Environmental and genetic determinants controlling biomineralization in magnetotactic bacteria(2014), 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), 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 d'Évry-Val-d'Essonne (UEVE), PSE-ENV/SRTE/LECO, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Signalisation de l'Adaptation des Végétaux à l'Environnement (SAVE), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-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)-Aix Marseille Université (AMU)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Laboratoire de Radioécologie et d'Ecotoxicologie (DEI/SECRE/LRE)
Subjects: Microbiology (medical), [SDV]Life Sciences [q-bio], Immunology, Magnetosome, Biology, medicine.disease_cause, Deltaproteobacteria, Applied Microbiology and Biotechnology, Microbiology, 03 medical and health sciences, Symbiosis, Genetics, medicine, Euglenozoa, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, Mutualism (biology), 0303 health sciences, 030306 microbiology, Protist, Magnetoreception, Cell Biology, biology.organism_classification, Anoxic waters, Evolutionary biology
Abstract: Mutualistic symbioses are often a source of evolutionary innovation and drivers of biological diversification1. Widely distributed in the microbial world, particularly in anoxic settings2,3, they often rely on metabolic exchanges and syntrophy2,4. Here, we report a mutualistic symbiosis observed in marine anoxic sediments between excavate protists (Symbiontida, Euglenozoa)5 and ectosymbiotic Deltaproteobacteria biomineralizing ferrimagnetic nanoparticles. Light and electron microscopy observations as well as genomic data support a multi-layered mutualism based on collective magnetotactic motility with division of labour and interspecies hydrogen-transfer-based syntrophy6. The guided motility of the consortia along the geomagnetic field is allowed by the magnetic moment of the non-motile ectosymbiotic bacteria combined with the protist motor activity, which is a unique example of eukaryotic magnetoreception7 acquired by symbiosis. The nearly complete deltaproteobacterial genome assembled from a single consortium contains a full magnetosome gene set8, but shows signs of reduction, with the probable loss of flagellar genes. Based on the metabolic gene content, the ectosymbiotic bacteria are anaerobic sulfate-reducing chemolithoautotrophs that likely reduce sulfate with hydrogen produced by hydrogenosome-like organelles6 underlying the plasma membrane of the protist. In addition to being necessary hydrogen sinks, ectosymbionts may provide organics to the protist by diffusion and predation, as shown by magnetosome-containing digestive vacuoles. Phylogenetic analyses of 16S and 18S ribosomal RNA genes from magnetotactic consortia in marine sediments across the Northern and Southern hemispheres indicate a host–ectosymbiont specificity and co-evolution. This suggests a historical acquisition of magnetoreception by a euglenozoan ancestor from Deltaproteobacteria followed by subsequent diversification. It also supports the cosmopolitan nature of this type of symbiosis in marine anoxic sediments. Here, the authors identify a mutualistic symbiosis between a non-motile, magnetic deltaproteobacterium and a protist, resulting in eukaryotic magnetoreception in marine anoxic sediments.
Published: 2019
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38. Magnetic Nanoparticles in Human Cervical Skin

Author: Kari Murros, Joonas Wasiljeff, Elena Macías-Sánchez, Damien Faivre, Lauri Soinne, Jussi Valtonen, Marjatta Pohja, Pekka Saari, Lauri J. Pesonen, Johanna M. Salminen, Neurologian yksikkö, HUS Neurocenter, Department of Geosciences and Geography, Long Terrestrial Archives, Clinicum, University Management, Plastiikkakirurgian yksikkö, HUS Musculoskeletal and Plastic Surgery, Staff Services, Department of Physics, Pediatric Neurology [Helsinki], Pediatric Research Center [Helsinki], Faculty of Medecine [Helsinki], University of Helsinki-University of Helsinki-Faculty of Medecine [Helsinki], University of Helsinki-University of Helsinki, Department of Geosciences and Geography [Helsinki], Falculty of Science [Helsinki], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Department of Neurology, Helsinki University Central Hospital, Helsinki University Central Hospital, University of Helsinki, Department of Physics [Helsinki], Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Faculty of Medecine [Helsinki], Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0301 basic medicine, 1171 Geosciences, skin, kin, magnetite, ALPHA-SYNUCLEIN, [SDV]Life Sciences [q-bio], Parkinson's disease, Maghemite, Nanoparticle, engineering.material, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, Nuclear magnetic resonance, PARKINSONS-DISEASE, superparamagnetic, PARTICLES, Magnetic anomaly, Magnetite, Original Research, lcsh:R5-920, SPECTROSCOPY, biology, Chemistry, IRON, General Medicine, SIZES, 3126 Surgery, anesthesiology, intensive care, radiology, FERRIHYDRITE, human tissue, Ferritin, REDUCTION, 030104 developmental biology, engineering, biology.protein, Magnetic nanoparticles, Medicine, gut, nanoparticles, lcsh:Medicine (General), FERRITIN, 030217 neurology & neurosurgery, Iron oxide nanoparticles, BEHAVIOR, Superparamagnetism
Abstract: International audience; Magnetic iron oxide nanoparticles, magnetite/maghemite, have been identified in human tissues, including the brain, meninges, heart, liver, and spleen. As these nanoparticles may play a role in the pathogenesis of neurodegenerative diseases, a pilot study explored the occurrence of these particles in the cervical (neck) skin of 10 patients with Parkinson's disease and 10 healthy controls. Magnetometry and transmission electron microscopy analyses revealed magnetite/maghemite nanoparticles in the skin samples of every study participant. Regarding magnetite/maghemite concentrations of the single-domain particles, no significant between-group difference was emerged. In low-temperature magnetic measurement, a magnetic anomaly at ∼50 K was evident mainly in the dermal samples of the Parkinson group. This anomaly was larger than the effect related to the magnetic ordering of molecular oxygen. The temperature range of the anomaly, and the size-range of magnetite/maghemite, both refute the idea of magnetic ordering of any iron phase other than magnetite. We propose that the explanation for the finding is interaction between clusters of superparamagnetic and single-domain-sized nanoparticles. The source and significance of these particles remains speculative.
Published: 2019
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39. Tribute in memory of Jacques Breton (1942–2018)

Author: Eliane Nabedryk, André Verméglio, Paul Mathis, Section de Bioénergétique Département de Biologie Cellulaire et Moléculaire, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0106 biological sciences, [SDV]Life Sciences [q-bio], Photosynthetic Reaction Center Complex Proteins, Biophysics, Tribute, Plant Science, 01 natural sciences, Biochemistry, History, 21st Century, Atomic energy commission, Visual arts, 03 medical and health sciences, Professional life, Sociology, Photosynthesis, 030304 developmental biology, 0303 health sciences, Bacteria, Cell Biology, General Medicine, Pigments, Biological, History, 20th Century, Plants, Energy Transfer, Photosynthetic bacteria, 010606 plant biology & botany
Abstract: International audience; Jacques Breton spent his 39 years of professional life at Saclay, a center of the French Atomic Energy Commission. He studied photosynthesis with various advanced biophysical tools, often developed by himself and his numerous coworkers, obtaining a large number of new information on the structure and the functioning of antenna and of reaction centers of plants and bacteria: excitation migration in the antenna, orientation of molecules, rate of primary reactions, binding of pigments and electron transfer cofactors. Although it is much too short to illustrate his impressive work, we hope that this contribution will help maintaining the souvenir of Jacques Breton as an active and enthusiastic person, full of qualities, devoted to research and to his family as well. We include personal comments from N. E. Geacintov, A. Dobek, W. Leibl, M. Vos and W. W. Parson.
Published: 2019
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40. Magnetosomes: biogenic iron nanoparticles produced by environmental bacteria

Author: Sandra Prévéral, Anissa Dieudonné, David Pignol, Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0303 health sciences, Magnetotactic bacteria, biology, Bacteria, 030306 microbiology, Chemistry, Iron, [SDV]Life Sciences [q-bio], Magnetosome, Nanotechnology, General Medicine, biology.organism_classification, Applied Microbiology and Biotechnology, Cancer treatment, 03 medical and health sciences, Environmental Microbiology, Nanoparticles, Magnetosomes, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, Biotechnology, Biomineralization
Abstract: The scientific community's interest in magnetotactic bacteria has increased substantially in recent decades. These prokaryotes have the particularity of synthesizing nanomagnets, called magnetosomes. The majority of research is based on several scientific questions. Where do magnetotactic bacteria live, what are their characteristics, and why are they magnetic? What are the molecular phenomena of magnetosome biomineralization and what are the physical characteristics of magnetosomes? In addition to scientific curiosity to better understand these stunning organisms, there are biotechnological opportunities to consider. Magnetotactic bacteria, as well as magnetosomes, are used in medical applications, for example cancer treatment, or in environmental ones, for example bioremediation. In this mini-review, we investigated all the aspects mentioned above and summarized the currently available knowledge.
Published: 2019
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41. Tuning the redox properties of a [4Fe-4S] center to modulate the activity of Mo-bisPGD periplasmic nitrate reductase

Author: Bruno Guigliarelli, David Pignol, Kamal Zeamari, Guillaume Gerbaud, Florence Chaspoul, Pascal Arnoux, Bénédicte Burlat, Monique Sabaty, Sandrine Grosse, Vincent Fourmond, Frédéric Biaso, Bioénergétique et Ingénierie des Protéines (BIP ), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), 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), and ANR-16-CE29-0010,MOLYERE,Comprendre et Contrôler la Réactivité du Cofacteur à Molybdène dans les Enzymes et les Protéines Maquettes(2016)
Subjects: Iron-Sulfur Proteins, 0301 basic medicine, Stereochemistry, [SDV]Life Sciences [q-bio], Mutation, Missense, Biophysics, Rhodobacter sphaeroides, 010402 general chemistry, Nitrate reductase, Nitrate Reductase, 01 natural sciences, Biochemistry, Redox, Electron Transport, 03 medical and health sciences, Electron transfer, Catalytic Domain, Redox titration, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS, biology, Chemistry, Active site, Cell Biology, Periplasmic space, biology.organism_classification, Electron transport chain, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, 030104 developmental biology, Amino Acid Substitution, biology.protein, Periplasmic Proteins, Oxidation-Reduction
Abstract: Molybdoenzymes are ubiquitous in living organisms and catalyze, for most of them, oxidation-reduction reactions using a large range of substrates. Periplasmic nitrate reductase (NapAB) from Rhodobacter sphaeroides catalyzes the 2-electron reduction of nitrate into nitrite. Its active site is a Mo bis-(pyranopterin guanine dinucleotide), or Mo-bisPGD, found in most prokaryotic molybdoenzymes. A [4Fe-4S] cluster and two c-type hemes form an intramolecular electron transfer chain that deliver electrons to the active site. Lysine 56 is a highly conserved amino acid which connects, through hydrogen-bonds, the [4Fe-4S] center to one of the pyranopterin ligands of the Mo-cofactor. This residue was proposed to be involved in the intramolecular electron transfer, either defining an electron transfer pathway between the two redox cofactors, and/or modulating their redox properties. In this work, we investigated the role of this lysine by combining site-directed mutagenesis, activity assays, redox titrations, EPR and HYSCORE spectroscopies. Removal of a positively-charged residue at position 56 strongly decreased the redox potential of the [4Fe-4S] cluster at pH 8 by 230 mV to 400 mV in the K56H and K56M mutants, respectively, thus affecting the kinetics of electron transfer from the hemes to the [4Fe-4S] center up to 5 orders of magnitude. This effect was partly reversed at acidic pH in the K56H mutant likely due to protonation of the imidazole ring of the histidine. Overall, our study demonstrates the critical role of a charged residue from the second coordination sphere in tuning the reduction potential of the [4Fe-4S] cluster in RsNapAB and related molybdoenzymes.
Published: 2019
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42. Control by Metals of Staphylopine Dehydrogenase Activity during Metallophore Biosynthesis

Author: Christine Hajjar, Roberto Fanelli, Clémentine Laffont, Catherine Brutesco, Gregorio Cullia, Mathilde Tribout, Didier Nurizzo, Elise Borezée-Durant, Romé Voulhoux, David Pignol, Jérôme Lavergne, Florine Cavelier, Pascal Arnoux, Microbiologie Environnementale et Moléculaire (MEM), 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), Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), MICrobiologie de l'ALImentation au Service de la Santé (MICALIS), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Association Vaincre la Mucoviscidose VLM, financement RFI20160501495, ANR-14-CE09-0007,ANIBAL,Un nouveau metallophore dérivé de la nicotianamine chez des bactéries pathogènes(2014), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-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), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-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)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Direction de Recherche Fondamentale (CEA) (DRF (CEA))
Subjects: Models, Molecular, 0303 health sciences, Staphylococcus aureus, pseudomonas-aeruginosa, 030306 microbiology, [SDV]Life Sciences [q-bio], Imidazoles, Molecular Conformation, crystal-structure, General Chemistry, nutritional immunity, Biochemistry, Catalysis, 03 medical and health sciences, Colloid and Surface Chemistry, iron, Metals, Heavy, transport, escherichia-coli, ions, Oxidoreductases, roles, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology
Abstract: International audience; Enzymatic regulations are central processes for the adaptation to changing environments. In the particular case of metallophore-dependent metal uptake, there is a need to quickly adjust the production of these metallophores to the metal level outside the cell, to avoid metal shortage or overload, as well as waste of metallophores. In Staphylococcus aureus, CntM catalyzes the last biosynthetic step in the production of staphylopine, a broad-spectrum metallophore, through the reductive condensation of a pathway intermediate (xNA) with pyruvate. Here, we describe the chemical synthesis of this intermediate, which was instrumental in the structural and functional characterization of CntM and confirmed its opine synthase properties. The three-dimensional structure of CntM was obtained in an "open" form, in the apo state or as a complex with substrate or product. The xNA substrate appears mainly stabilized by its imidazole ring through a pi-pi interaction with the side chain of Tyr240. Intriguingly, we found that metals exerted various and sometime antagonistic effects on the reaction catalyzed by CntM: zinc and copper are moderate activators at low concentration and then total inhibitors at higher concentration, whereas manganese is only an activator and cobalt and nickel are only inhibitors. We propose a model in which the relative affinity of a metal toward xNA and an inhibitory binding site on the enzyme controls activation, inhibition, or both as a function of metal concentration. This metal-dependent regulation of a metallophore-producing enzyme might also take place in vivo, which could contribute to the adjustment of metallophore production to the internal metal level.
Published: 2019
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43. Reducing Conditions Favor Magnetosome Production in Magnetospirillum magneticum AMB-1

Author: Gabriele Schiro, Victoria Reichel, Damien Faivre, Agata Olszewska-Widdrat, Department of Biomaterials [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Microbiologie Environnementale et Moléculaire (MEM), 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), 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: Microbiology (medical), Greigite, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, magnetite, Magnetotactic bacteria, Microorganism, Magnetosome, lcsh:QR1-502, Microbiology, lcsh:Microbiology, redox potential, 03 medical and health sciences, chemistry.chemical_compound, iron, Organelle, 030304 developmental biology, Magnetite, 0303 health sciences, biology, 030306 microbiology, magnetotactic bacteria, biology.organism_classification, biomineralization, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, chemistry, Biophysics, Bacteria, Biomineralization
Abstract: Magnetotactic bacteria (MTB) are a heterogeneous group of Gram-negative prokaryotes, which all produce special magnetic organelles called magnetosomes. The magnetosome consists of a magnetic nanoparticle, either magnetite (Fe3O4) or greigite (Fe3S4), embedded in a membrane, which renders the systems colloidaly stable, a desirable property for biotechnological applications. Although these bacteria are able to regulate the formation of magnetosomes through a biologically-controlled mechanism, the environment in general and the physico-chemical conditions surrounding the cells in particular also influence biomineralization. This work thus aims at understanding how such external conditions, in particular the extracellular oxidation reduction potential, influence magnetite formation in the strain Magnetospirillum magneticum AMB-1. Controlled cultivation of the microorganisms was performed at different redox potential in a bioreactor and the formation of magnetosomes was assessed by microscopic and spectroscopic techniques. Our results show that the formation of magnetosomes is inhibited at the highest potential tested (0 mV), whereas biomineralization is facilitated under reduced conditions (-500 mV). This result improves the understanding of the biomineralization process in MTB and provides useful information in sight of a large scale production of magnetosomes for different applications. © 2019 Olszewska-Widdrat, Schiro, Reichel and Faivre.
Published: 2019
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44. Variability in the redox status of plant 2-Cys peroxiredoxins in relation to species and light cycle

Author: Delphine Cerveau, Pascal Rey, Patricia Henri, Laurence Blanchard, Protéines de Protection des Végétaux (PPV), 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), Microbiologie Environnementale et Moléculaire (MEM), 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, Physiology, Dimer, [SDV]Life Sciences [q-bio], Photoperiod, redox status, Arabidopsis, plant, Plant Science, Photosynthesis, 01 natural sciences, 03 medical and health sciences, chemistry.chemical_compound, Species Specificity, content, Cysteine, Plastid, plastid, 030304 developmental biology, Plant Proteins, Solanum tuberosum, chemistry.chemical_classification, 0303 health sciences, biology, thiol, peroxiredoxin, Hordeum, Peroxiredoxins, biology.organism_classification, Enzyme, chemistry, Biochemistry, Protein quaternary structure, Peroxiredoxin, signaling, Oxidation-Reduction, 010606 plant biology & botany
Abstract: Plant 2-Cys peroxiredoxins (2-CysPRXs) are abundant plastidial thiol-peroxidases involved in key signaling processes such as photosynthesis deactivation at night. Their functions rely on the redox status of their two cysteines and on the enzyme quaternary structure, knowledge of which remains poor in plant cells. Using ex vivo and biochemical approaches, we thoroughly characterized the 2-CysPRX dimer/monomer distribution, hyperoxidation level, and thiol content in Arabidopsis, barley, and potato in relation to the light cycle. Our data reveal that the enzyme hyperoxidization level and its distribution as a dimer and monomer vary through the light cycle in a species-dependent manner. A differential susceptibility to hyperoxidation was observed for the two Arabidopsis 2-CysPRX isoforms and among the proteins of the three species, and was associated to sequence variation in hyperoxidation resistance motifs. Alkylation experiments indicate that only a minor fraction of the 2-CysPRX pool carries one free thiol in the three species, and that this content does not change during the light period. We conclude that most plastidial 2-CysPRX forms are oxidized and propose that there is a species-dependent variability in their functions since dimer and hyperoxidized forms fulfill distinct roles regarding direct oxidation of partners and signal transmission.
Published: 2019
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45. Magnetic Nanoparticle Chains in Gelatin Ferrogels: Bioinspiration from Magnetotactic Bacteria

Author: Karin Vogel, Bernd Büchner, Daniel Wolf, Axel Lubk, Micha Gratz, Elena V. Sturm, Helmut Cölfen, Sebastian Sturm, Damien Faivre, Maria Siglreitmeier, Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, University of Konstanz, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Saarland University [Saarbrücken], Microbiologie Environnementale et Moléculaire (MEM), 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), Department of Colloid Chemistry [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, 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: Materials science, electron holography, magnetite, Magnetotactic bacteria, [SDV]Life Sciences [q-bio], electron tomography, FOS: Physical sciences, Nanoparticle, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Electron holography, Biomaterials, gelatin, Magnetization, chemistry.chemical_compound, Ferrimagnetism, Electrochemistry, ComputingMilieux_MISCELLANEOUS, Magnetite, Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Magnetic anisotropy, Chemical engineering, Electron tomography, chemistry, bioinspiration, ddc:540, 0210 nano-technology
Abstract: Inspired by chains of ferrimagnetic nanocrystals (NCs) in magnetotactic bacteria (MTB), the synthesis and detailed characterization of ferrimagnetic magnetite NC chain-like assemblies is reported. An easy green synthesis route in a thermoreversible gelatin hydrogel matrix is used. The structure of these magnetite chains prepared with and without gelatin is characterized by means of transmission electron microscopy, including electron tomography (ET). These structures indeed bear resemblance to the magnetite assemblies found in MTB, known for their mechanical flexibility and outstanding magnetic properties and known to crystallographically align their magnetite NCs along the strongest magnetization easy axis. Using electron holography (EH) and angular dependent magnetic measurements, the magnetic interaction between the NCs and the generation of a magnetically anisotropic material can be shown. The electro- and magnetostatic modeling demonstrates that in order to precisely determine the magnetization (by means of EH) inside chain-like NCs assemblies, their exact shape, arrangement and stray-fields have to be considered (ideally obtained using ET). �� 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Published: 2019
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46. Bioinspired multifunctional layered magnetic hybrid materials

Author: DebusChristian, FaivreDamien, HerreraSteven, CölfenHelmut, ZahnDirk, WuBaohu, KisailusDavid, DuchsteinPatrick, PipichVitaliy, BenkeDominik, SchwahnDietmar, KollmannTina, SiglreitmeierMaria, University of Konstanz, Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ), Department of Computer Science [Erlangen], Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), University of California [Riverside] (UC Riverside), University of California (UC), University of Bayreuth, Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Microbiologie Environnementale et Moléculaire (MEM), 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), Max Planck Institute for Chemical Physics of Solids (CPfS), Max-Planck-Gesellschaft, Department of Colloid Chemistry [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, University of California [Riverside] (UCR), University of California, 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: Engineering, business.industry, 0206 medical engineering, General Engineering, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, bioinspired, composite materials, hybrid materials, 021001 nanoscience & nanotechnology, 020601 biomedical engineering, Biomaterials, ddc:540, 0210 nano-technology, Hybrid material, business, Limited resources, ComputingMilieux_MISCELLANEOUS
Abstract: Nature has taken millennia to come up with unique solutions for providing materials with properties tailored toward versatile demands, making use of the very limited resources available in natural environments. Today, these biomaterials can be used as inspiration by combining and ‘remixing’ the concepts that nature displays to create new bioinspired materials. Here, the authors present materials combining the structural and functional elements of multiple biominerals: the inorganic–organic lamellar structure responsible for the high fracture toughness of nacre; highly mineralized composites, which give different mollusk teeth their very high hardness and strength; and the particle orientation and magnetic anisotropy of magnetosomes, giving magnetotactic bacteria a sensitive means to navigate along geomagnetic field lines. The authors show how the mechanical properties of a composite material can be improved with the addition of each of these elements. Small-angle neutron scattering studies and molecular simulation give additional insights into the mineralization from the very first attached ions to the finished composite.
Published: 2019
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47. Reduction of Protein Bound Methionine Sulfoxide by a Periplasmic Dimethyl Sulfoxide Reductase

Author: Lionel Tarrago, Mila Kojadinovic-Sirinelli, David Lemaire, Monique Sabaty, Marina I. Siponen, Sandrine Grosse, David Pignol, Mathilde Tribout, Pascal Arnoux, Laetitia Faure, Biodiversité et Biotechnologie Fongiques (BBF), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Microbiologie Environnementale et Moléculaire (MEM), 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), Interactions Protéine Métal (IPM), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT), ANR-16-CE11-0012,METOXIC,Enzyme de réparation des protéines oxydées: un nouveau système de contrôle qualité dans le périplasme(2016), ANR-16-CE29-0010,MOLYERE,Comprendre et Contrôler la Réactivité du Cofacteur à Molybdène dans les Enzymes et les Protéines Maquettes(2016), 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), Institut National des Sciences Appliquées (INSA), Tarrago, Lionel, Enzyme de réparation des protéines oxydées: un nouveau système de contrôle qualité dans le périplasme - - METOXIC2016 - ANR-16-CE11-0012 - AAPG2016 - VALID, Comprendre et Contrôler la Réactivité du Cofacteur à Molybdène dans les Enzymes et les Protéines Maquettes - - MOLYERE2016 - ANR-16-CE29-0010 - AAPG2016 - VALID, and Institut National des Sciences Appliquées (INSA)-Université Fédérale Toulouse Midi-Pyrénées
Subjects: Physiology, [SDV]Life Sciences [q-bio], Clinical Biochemistry, Rhodobacter sphaeroides, Protein oxidation, Biochemistry, Article, methionine sulfoxide, 03 medical and health sciences, chemistry.chemical_compound, enzyme kinetics, [SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology, oxidative stress, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, protein oxidation, protein quality control, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], [SDV.BBM.BC] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, Molecular Biology, 030304 developmental biology, dimethyl sulfoxide reductase, 0303 health sciences, DMSO reductase, Methionine, 030306 microbiology, Chemistry, Methionine sulfoxide, Dimethyl sulfoxide, lcsh:RM1-950, Sulfoxide, Cell Biology, Periplasmic space, [SDV] Life Sciences [q-bio], [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, lcsh:Therapeutics. Pharmacology, Methionine sulfoxide reductase
Abstract: In proteins, methionine (Met) can be oxidized into Met sulfoxide (MetO). The ubiquitous methionine sulfoxide reductases (Msr) A and B are thiol-oxidoreductases reducing MetO. Reversible Met oxidation has a wide range of consequences, from protection against oxidative stress to fine-tuned regulation of protein functions. Bacteria distinguish themselves by the production of molybdenum-containing enzymes reducing MetO, such as the periplasmic MsrP which protects proteins during acute oxidative stress. The versatile dimethyl sulfoxide (DMSO) reductases were shown to reduce the free amino acid MetO, but their ability to reduce MetO within proteins was never evaluated. Here, using model oxidized proteins and peptides, enzymatic and mass spectrometry approaches, we showed that the Rhodobacter sphaeroides periplasmic DorA-type DMSO reductase reduces protein bound MetO as efficiently as the free amino acid L-MetO and with catalytic values in the range of those described for the canonical Msrs. The identification of this fourth type of enzyme able to reduce MetO in proteins, conserved across proteobacteria and actinobacteria, suggests that organisms employ enzymatic systems yet undiscovered to regulate protein oxidation states.
Published: 2020
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48. $Rhodobacter\ sphaeroides$ methionine sulfoxide reductase P reduces $R$ ‑ and $S$ ‑diastereomers of methionine sulfoxide from a broad‑spectrum of protein substrates

Author: Sandrine Grosse, Guylaine Miotello, Pascal Arnoux, David Lemaire, Lionel Tarrago, Marina I. Siponen, Jean Armengaud, David Pignol, Béatrice Alonso, Monique Sabaty, 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), Interactions Protéine Métal (IPM), Laboratoire Innovations technologiques pour la Détection et le Diagnostic (LI2D), Service de Pharmacologie et Immunoanalyse (SPI), Médicaments et Technologies pour la Santé (MTS), Université Paris-Saclay-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 Paris-Saclay-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)-Médicaments et Technologies pour la Santé (MTS), 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), Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA) [ANR 16-CE11-0012], ANR-16-CE11-0012,METOXIC,Enzyme de réparation des protéines oxydées: un nouveau système de contrôle qualité dans le périplasme(2016), 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: 0301 basic medicine, proteomics 15, [SDV]Life Sciences [q-bio], Protein oxidation, Biochemistry, 03 medical and health sciences, chemistry.chemical_compound, Rhodobacter sphaeroides, protein oxidation, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Molecular Biology, periplasm, Methionine, biology, Methionine sulfoxide, microbiology, Enzyme kinetics, molybdoenzyme, Cell Biology, Periplasmic space, biology.organism_classification, oxidative 14 stress, 030104 developmental biology, chemistry, methionine sulfoxide reductase, Methionine sulfoxide reductase, Photosynthetic bacteria, MSRA
Abstract: International audience; Methionine (Met) is prone to oxidation and can be converted to Met sulfoxide (MetO), which exists as $R$- and $S$-diastereomers. MetO can be reduced back to Met by the ubiquitous methionine sulfoxide reductase (Msr) enzymes. Canonical MsrA and MsrB were shown to be absolutely stereospecific for the reduction of S ‑ and R‑ diastereomer, respectively. Recently, a new enzymatic system, MsrQ/MsrP which is conserved in all gram‑negative bacteria, was identified as a key actor in the reduction of oxidized periplasmic proteins. The haem‑binding membrane protein MsrQ transmits reducing power from the electron transport chains to the molybdoenzyme MsrP, which acts as a protein‑MetO reductase. The MsrQ/MsrP function was well established genetically, but the identity and biochemical properties of MsrP substrates remain unknown. In this work, using the purified MsrP enzyme from the photosynthetic bacteria $Rhodobacter\ sphaeroides$ as a model, we show that it can reduce a broad spectrum of protein substrates. The most efficiently reduced MetO are found in clusters of amino acid sequences devoid of threonine and proline on the C‑terminal side. Moreover, $R.\ sphaeroides$ MsrP lacks stereospecificity as it can reduce both R‑ and S‑ diastereomers of MetO, similarly to its $Escherichia\ coli$ homolog, and preferentially acts on unfolded oxidized proteins. Overall, these results provide important insights into the function of a bacterial envelop protecting system, which should help understand how bacteria cope in harmful environments.
Published: 2018
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49. Native-state imaging of calcifying and noncalcifying microalgae reveals similarities in their calcium storage organelles

Author: Assaf Gal, Keren Kahil, Andrea Sorrentino, Damien Faivre, André Scheffel, Eva Pereiro, Max Planck Institute of Molecular Plant Physiology (MPI-MP), Max-Planck-Gesellschaft, ALBA Synchrotron light source [Barcelone], Weizmann Institute of Science [Rehovot, Israël], Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 0301 basic medicine, Coccolithophore, Oceans and Seas, [SDV]Life Sciences [q-bio], chemistry.chemical_element, Calcium, Calcium in biology, Calcium Carbonate, Coccolith, 03 medical and health sciences, Calcification, Physiologic, Polyphosphates, cryo–X-ray tomography, Microalgae, Homeostasis, coccolithophore, Pleurochrysis carterae, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, Calcium signaling, Organelles, Minerals, Multidisciplinary, biology, intracellular calcium store, Haptophyta, Phosphorus, Biological Sciences, biomineralization, biology.organism_classification, Acidocalcisome, Chemistry, 030104 developmental biology, chemistry, Physical Sciences, acidocalcisome, Biophysics, Acids, Environmental Sciences, Chlamydomonas reinhardtii, Biomineralization
Abstract: Significance Coccolithophores are abundant unicellular marine algae that produce calcified scales via a controlled intracellular process. Understanding the cellular controls over the calcification process is a pressing need to predict the influence of changing oceanic conditions on these major contributors to global marine calcification and carbon fluxes. Using several microalgae, and a combination of state-of-the-art cryoelectron and cryo soft X-ray microscopy, we demonstrate that the recently discovered calcium stores of coccolithophores are similar to the common calcium storage organelles of noncalcifying organisms. These results relate questions of environmental and evolutionary significance to a large body of physiological and molecular genetic findings of better-characterized organisms, and therefore provide fresh entry points for understanding calcification in coccolithophores., Calcium storage organelles are common to all eukaryotic organisms and play a pivotal role in calcium signaling and cellular calcium homeostasis. In most organelles, the intraorganellar calcium concentrations rarely exceed micromolar levels. Acidic organelles called acidocalcisomes, which concentrate calcium into dense phases together with polyphosphates, are an exception. These organelles have been identified in diverse organisms, but, to date, only in cells that do not form calcium biominerals. Recently, a compartment storing molar levels of calcium together with phosphorous was discovered in an intracellularly calcifying alga, the coccolithophore Emiliania huxleyi, raising a possible connection between calcium storage organelles and calcite biomineralization. Here we used cryoimaging and cryospectroscopy techniques to investigate the anatomy and chemical composition of calcium storage organelles in their native state and at nanometer-scale resolution. We show that the dense calcium phase inside the calcium storage compartment of the calcifying coccolithophore Pleurochrysis carterae and the calcium phase stored in acidocalcisomes of the noncalcifying alga Chlamydomonas reinhardtii have common features. Our observations suggest that this strategy for concentrating calcium is a widespread trait and has been adapted for coccolith formation. The link we describe between acidocalcisomal calcium storage and calcium storage in coccolithophores implies that our physiological and molecular genetic understanding of acidocalcisomes could have relevance to the calcium pathway underlying coccolithophore calcification, offering a fresh entry point for mechanistic investigations on the adaptability of this process to changing oceanic conditions.
Published: 2018
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50. Bead-Based Hydrodynamic Simulations of Rigid Magnetic Micropropellers

Author: Agnese Codutti, Felix Bachmann, Damien Faivre, Stefan Klumpp, Department of Biomaterials [Potsdam], Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), 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), Microbiologie Environnementale et Moléculaire (MEM), 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)), Department of Nonlinear Dynamics [Göttingen], Max Planck Institute for Dynamics and Self-Organization (MPIDS), Deutsche Forschungsgemeinschaft within the Priority Program 1726 on microswimmers : FA 835/7-2 et KL 818/2-2IMPRS on Multiscale Biosystems, Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: randomly shaped, magnetics, Field (physics), lcsh:Mechanical engineering and machinery, Coordinate system, 02 engineering and technology, Propulsion, 01 natural sciences, lcsh:QA75.5-76.95, Quantitative Biology::Cell Behavior, [SPI.AUTO]Engineering Sciences [physics]/Automatic, Artificial Intelligence, Orientation (geometry), 0103 physical sciences, micropropeller, lcsh:TJ1-1570, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Original Research, Robotics and AI, Physics, Physics::Biological Physics, bead approximation, Propeller, Mechanics, simulation, 021001 nanoscience & nanotechnology, Computer Science Applications, Magnetic field, SPHERES, lcsh:Electronic computers. Computer science, 0210 nano-technology, Energy source
Abstract: The field of synthetic microswimmers, micro-robots moving in aqueous environments, has evolved significantly in the last years. Micro-robots actuated and steered by external magnetic fields are of particular interest because of the biocompatibility of this energy source and the possibility of remote control, features suited for biomedical applications. While initial work has mostly focused on helical shapes, the design space under consideration has widened considerably with recent works, opening up new possibilities for optimization of propellers to meet specific requirements. Understanding the relation between shape on the one hand and targeted actuation and steerability on the other hand requires an understanding of their propulsion behavior. Here we propose hydrodynamic simulations for the characterization of rigid micropropellers of any shape, actuated by rotating external magnetic fields. We approximate the shape of micropropellers by an ensemble of rigidly connected spheres, for which the mobility matrices can be calculated via the method of reflections. We characterize the influence of model parameters such as bead size, distance between beads and magnetic properties on the swimming behavior of helical propellers to identify optimal simulation parameters. We then apply the simulation to randomly shaped propeller, specifically to a recently characterized propeller shape and study their frequency- dependent swimming behaviors. The simulations show that the orientation of the magnetic moment with respect to the propeller’s internal coordinate system has a strong impact on the propulsion behavior and has to be known with a precision of ≤ 5 ◦ to predict the propeller’s velocity-frequency curve. This result emphasizes the importance of the magnetic properties of the micropropellers for the design of desired functionalities for potential biomedical applications, and in particular the importance of their orientation within the propeller’s structure.
Published: 2018
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