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Accueil > Plateformes > Plateformes IMAGERIE-GIF : Cytométrie, Microscopie Electronique & Microscopie Photonique > Publications & Communications

Publications & Communications

Publications

Cytométrie

2019


  • E. Bordet, M. Frétaud, E. Crisci, E. Bouguyon, S. Rault, J. Pezant, A. Pleau, P. Renson, E. Giuffra, T. Larcher, M. Bourge, O. Bourry, O. Boulesteix, C. Langevin, I. Schwartz-Cornil, et N. Bertho, « Macrophage-B Cell Interactions in the Inverted Porcine Lymph Node and Their Response to Porcine Reproductive and Respiratory Syndrome Virus », Frontiers in Immunology, vol. 10, p. 953, 2019.

    Résumé : Swine lymph nodes (LN) present an inverted structure compared to mouse and human, with the afferent lymph diffusing from the center to the periphery. This structure, also observed in close and distant species such as dolphins, hippopotamus, rhinoceros, and elephants, is poorly described, nor are the LN macrophage populations and their relationship with B cell follicles. B cell maturation occurs mainly in LN B cell follicles with the help of LN macrophage populations endowed with different antigen delivery capacities. We identified three macrophage populations that we localized in the inverted LN spatial organization. This allowed us to ascribe porcine LN MΦ to their murine counterparts: subcapsular sinus MΦ, medullary cord MΦ and medullary sinus MΦ. We identified the different intra and extrafollicular stages of LN B cells maturation and explored the interaction of MΦ, drained antigen and follicular B cells. The porcine reproductive and respiratory syndrome virus (PRRSV) is a major porcine pathogen that infects tissue macrophages (MΦ). PRRSV is persistent in the secondary lymphoid tissues and induces a delay in neutralizing antibodies appearance. We observed PRRSV interaction with two LN MΦ populations, of which one interacts closely with centroblasts. We observed BCL6 up-regulation in centroblast upon PRRSV infection, leading to new hypothesis on PRRSV inhibition of B cell maturation. This seminal study of porcine LN will permit fruitful comparison with murine and human LN for a better understanding of normal and inverted LN development and functioning.
    Mots-clés : antibodies, antigen, B cell, BCL6, CYTO, PF, PRRSV.


  • V. Paalme, A. Rump, K. Mädo, M. Teras, B. Truumees, H. Aitai, K. Ratas, M. Bourge, C. - S. Chiang, A. Ghalali, T. Tordjmann, J. Teras, P. Boudinot, J. M. Kanellopoulos, et S. Rüütel Boudinot, « Human Peripheral Blood Eosinophils Express High Levels of the Purinergic Receptor P2X4 », Frontiers in Immunology, vol. 10, p. 2074, 2019.

    Résumé : Extracellular nucleotides are important mediators of cell activation and trigger multiple responses via membrane receptors known as purinergic receptors (P2). P2X receptors are ligand-gated ion channels, activated by extracellular ATP. P2X4 is one of the most sensitive purinergic receptors, that is typically expressed by neurons, microglia, and some epithelial and endothelial cells. P2X4 mediates neuropathic pain via brain-derived neurotrophic factor and is also involved in inflammation in response to high ATP release. It is therefore involved in multiple inflammatory pathologies as well as neurodegenerative diseases. We have produced monoclonal antibodies (mAb) directed against this important human P2X4 receptor. Focusing on two mAbs, we showed that they also recognize mouse and rat P2X4. We demonstrated that these mAbs can be used in flow cytometry, immunoprecipitation, and immunohistochemistry, but not in Western blot assays, indicating that they target conformational epitopes. We also characterized the expression of P2X4 receptor on mouse and human peripheral blood lymphocytes (PBL). We showed that P2X4 is expressed at the surface of several leukocyte cell types, with the highest expression level on eosinophils, making them potentially sensitive to adenosine triphosphate (ATP). P2X4 is expressed by leucocytes, in human and mouse, with a significant gender difference, males having higher surface expression levels than females. Our findings reveal that PBL express significant levels of P2X4 receptor, and suggest an important role of this receptor in leukocyte activation by ATP, particularly in P2X4high expressing eosinophils.
    Mots-clés : B3S, CYTO, Eosinophils, MIP, Monoclonal antibody, P2X4 purinergic receptor, PBL marker, PF.
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2018



  • T. Avin-Wittenberg, F. Baluška, P. V. Bozhkov, P. H. Elander, A. R. Fernie, G. Galili, A. Hassan, D. Hofius, E. Isono, R. Le Bars, C. Masclaux-Daubresse, E. A. Minina, H. Peled-Zehavi, N. S. Coll, L. M. Sandalio, B. Satiat-Jeunemaitre, A. Sirko, P. S. Testillano, et H. Batoko, « Autophagy-related approaches for improving nutrient use efficiency and crop yield protection », Journal of Experimental Botany, vol. 69, nᵒ 6, p. 1335-1353, mars 2018.

    Mots-clés : BIOCELL, CYTO, DYNBSJ, PF, PHOT.

  • T. Avin-Wittenberg, F. Baluška, P. V. Bozhkov, P. H. Elander, A. R. Fernie, G. Galili, A. Hassan, D. Hofius, E. Isono, R. Le Bars, C. Masclaux-Daubresse, E. A. Minina, H. Peled-Zehavi, N. S. Coll, L. M. Sandalio, B. Satiat-Jeunemaitre, A. Sirko, P. S. Testillano, et H. Batoko, « Corrigendum: Autophagy-related approaches for improving nutrient use efficiency and crop yield protection », Journal of Experimental Botany, vol. 69, nᵒ 12, p. 3173, mai 2018.

    Mots-clés : BIOCELL, CYTO, DYNBSJ, PF, PHOT.

  • E. Bordet, F. Blanc, M. Tiret, E. Crisci, E. Bouguyon, P. Renson, P. Maisonnasse, M. Bourge, J. - J. Leplat, E. Giuffra, L. Jouneau, I. Schwartz-Cornil, O. Bourry, et N. Bertho, « Porcine Reproductive and Respiratory Syndrome Virus Type 1.3 Lena Triggers Conventional Dendritic Cells 1 Activation and T Helper 1 Immune Response Without Infecting Dendritic Cells », Frontiers in Immunology, vol. 9, p. 2299, oct. 2018.

    Résumé : Porcine Reproductive and Respiratory Syndrome virus (PRRSV) is an arterivirus responsible for highly contagious infection and huge economic losses in pig industry. Two species, PRRSV-1 and PRRSV-2 are distinguished, PRRSV-1 being more prevalent in Europe. PRRSV-1 can further be divided in subtypes. PRRSV-1.3 such as Lena are more pathogenic than PRRSV-1.1 such as Lelystad or Flanders13. PRRSV-1.3 viruses trigger a higher Th1 response than PRRSV-1.1, although the role of the cellular immune response in PRRSV clearance remains ill defined. The pathogenicity as well as the T cell response inductions may be differentially impacted according to the capacity of the virus strain to infect and/or activate DCs. However, the interactions of PRRSV with in vivo-differentiated-DC subtypes such as conventional DC1 (cDC1), cDC2, and monocyte-derived DCs (moDC) have not been thoroughly investigated. Here, DC subpopulations from Lena in vivo infected pigs were analyzed for viral genome detection. This experiment demonstrates that cDC1, cDC2, and moDC are not infected in vivo by Lena. Analysis of DC cytokines production revealed that cDC1 are clearly activated in vivo by Lena. In vitro comparison of 3 Europeans strains revealed no infection of the cDC1 and cDC2 and no or little infection of moDC with Lena, whereas the two PRRSV1.1 strains infect none of the 3 DC subtypes. In vitro investigation of T helper polarization and cytokines production demonstrate that Lena induces a higher Th1 polarization and IFN gamma secretion than FL13 and LV. Altogether, this work suggests an activation of cDC1 by Lena associated with a Th1 immune response polarization.
    Mots-clés : blood, cDc1, cellular response, CYTO, dendritic cells, differentiation, dust mite allergen, europe, Lena, lung, macrophages, monocytes, PF, pigs, prrsv, prrsv strain, sialoadhesin, swine, Th1 response.

  • L. Brottier, C. Chaintreuil, P. Simion, C. Scornavacca, R. Rivallan, P. Mournet, L. Moulin, G. P. Lewis, J. Fardoux, S. C. Brown, M. Gomez-Pacheco, M. Bourges, C. Hervouet, M. Gueye, R. Duponnois, H. Ramanankierana, H. Randriambanona, H. Vandrot, M. Zabaleta, M. DasGupta, A. D'Hont, E. Giraud, et J. - F. Arrighi, « A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses », BMC plant biology, vol. 18, nᵒ 1, p. 333, déc. 2018.

    Résumé : BACKGROUND: Among semi-aquatic species of the legume genus Aeschynomene, some have the property of being nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the synthesis of Nod factors. Knowledge of the specificities underlying this Nod-independent symbiosis has been gained from the model legume Aeschynomene evenia but our understanding remains limited due to the lack of comparative genetics with related taxa using a Nod factor-dependent process. To fill this gap, we combined different approaches to perform a thorough comparative analysis in the genus Aeschynomene. RESULTS: This study significantly broadened previous taxon sampling, including in allied genera, in order to construct a comprehensive phylogeny. In the phylogenetic tree, five main lineages were delineated, including a novel lineage, the Nod-independent clade and another one containing a polytomy that comprised several Aeschynomene groups and all the allied genera. This phylogeny was matched with data on chromosome number, genome size and low-copy nuclear gene sequences to reveal the diploid species and a polytomy containing mostly polyploid taxa. For these taxa, a single allopolyploid origin was inferred and the putative parental lineages were identified. Finally, nodulation tests with different Bradyrhizobium strains revealed new nodulation behaviours and the diploid species outside of the Nod-independent clade were compared for their experimental tractability and genetic diversity. CONCLUSIONS: The extended knowledge of the genetics and biology of the different lineages sheds new light of the evolutionary history of the genus Aeschynomene and they provide a solid framework to exploit efficiently the diversity encountered in Aeschynomene legumes. Notably, our backbone tree contains all the species that are diploid and it clarifies the genetic relationships between the Nod-independent clade and the Nod-dependent lineages. This study enabled the identification of A. americana and A. patula as the most suitable species to undertake a comparative genetic study of the Nod-independent and Nod-dependent symbioses.
    Mots-clés : Aeschynomene, ancient, CHERDIR, CYTO, diversity, evenia, evolutionary dynamics, fixing stem nodules, Genetics, Legumes, leguminosae, model, Nodulation, PF, Phylogenetics, Polyploidy, Symbiosis.


  • C. Chaintreuil, X. Perrier, G. Martin, J. Fardoux, G. P. Lewis, L. Brottier, R. Rivallan, M. Gomez-Pacheco, M. Bourges, L. Lamy, B. Thibaud, H. Ramanankierana, H. Randriambanona, H. Vandrot, P. Mournet, E. Giraud, et J. - F. Arrighi, « Naturally occurring variations in the nod-independent model legume Aeschynomene evenia and relatives: a resource for nodulation genetics », BMC Plant Biology, vol. 18, nᵒ 1, 2018.


  • S. Malli, C. Bories, M. Bourge, P. M. Loiseau, et K. Bouchemal, « Surface-dependent endocytosis of poly(isobutylcyanoacrylate) nanoparticles by Trichomonas vaginalis », International Journal of Pharmaceutics, vol. 548, nᵒ 1, p. 276-287, sept. 2018.

    Résumé : Previous data from our research group showed that chitosan-coated poly(isobutylcyanoacrylate) nanoparticles (NPs) (denoted PIBCA/Chito20) exhibited intrinsic anti-Trichomonas vaginalis activity, while PIBCA/pluronic (R) F68 without chitosan (PIBCA/F68) were inactive. However, the mechanism of anti-T. vaginalis activity of chitosan-coated PIBCA NPs is still unknown. Our hypothesis is that chitosan-coated NPs are internalized by the parasite, contrarily to PIBCA/F68. In this investigation, the impact of NP surface on their internalization by the protozoan was studied using flow cytometry and parasite morphological changes after different incubation times with PIBCA/Chito20 NPs were monitored by electron microscopy. Flow-cytometry revealed that PIBCA/Chito20 NPs were uptaken by T. vaginalis as early as 10-min-incubation. Drastic cell morphological transformations were observed from scanning electron microscopy and transmission electron microscopy after incubation with PIBCA/Chito20 NPs. Numerous pits were seen on cell membrane since 10 min. Gradual increase in contact time increased NP endocytosis and induced proportional damages to T. vaginalis membrane. Then, investigation of whether PIBCA/Chito20 NPs can improve MTZ anti-T. vaginalis activity was studied using checkerboard experiment. Calculation of fractional inhibitory concentration index (FICI = 3.53) showed an additive effect between NPs and MTZ.
    Mots-clés : Chitosan, CYTO, Metronidazole, PF, Poly(isobutylcyanoacrylate), Trichomonas vaginalis.

  • J. Marion, R. Le Bars, L. Besse, H. Batoko, et B. Satiat-Jeunemaitre, « Multiscale and Multimodal Approaches to Study Autophagy in Model Plants », Cells, vol. 7, nᵒ 1, janv. 2018.

    Résumé : Autophagy is a catabolic process used by eukaryotic cells to maintain or restore cellular and organismal homeostasis. A better understanding of autophagy in plant biology could lead to an improvement of the recycling processes of plant cells and thus contribute, for example, towards reducing the negative ecological consequences of nitrogen-based fertilizers in agriculture. It may also help to optimize plant adaptation to adverse biotic and abiotic conditions through appropriate plant breeding or genetic engineering to incorporate useful traits in relation to this catabolic pathway. In this review, we describe useful protocols for studying autophagy in the plant cell, taking into account some specificities of the plant model.
    Mots-clés : Arabidopsis, autophagosome, Autophagy, autophagy assays, BIOCELL, CYTO, DYNBSJ, methods, PHOT, plant cells, Tobacco.

  • J. Pirrello, C. Deluche, N. Frangne, F. Gévaudant, E. Maza, A. Djari, M. Bourge, J. - P. Renaudin, S. Brown, C. Bowler, M. Zouine, C. Chevalier, et N. Gonzalez, « Transcriptome profiling of sorted endoreduplicated nuclei from tomato fruits: how the global shift in expression ascribed to DNA ploidy influences RNA-Seq data normalization and interpretation », The Plant Journal: For Cell and Molecular Biology, vol. 93, nᵒ 2, p. 387-398, 2018.

    Résumé : As part of normal development most eukaryotic organisms, ranging from insects and mammals to plants, display variations in nuclear ploidy levels resulting from somatic endopolyploidy. Endoreduplication is the major source of endopolyploidy in higher plants. Endoreduplication is a remarkable characteristic of the fleshy pericarp tissue of developing tomato fruits, where it establishes a highly integrated cellular system that acts as a morphogenetic factor supporting cell growth. However, the functional significance of endoreduplication is not fully understood. Although endoreduplication is thought to increase metabolic activity due to a global increase in transcription, the issue of gene-specific ploidy-regulated transcription remains open. To investigate the influence of endoreduplication on transcription in tomato fruit, we tested the feasibility of a RNA sequencing (RNA-Seq) approach using total nuclear RNA extracted from purified populations of flow cytometry-sorted nuclei based on their DNA content. Here we show that cell-based approaches to the study of RNA-Seq profiles need to take into account the putative global shift in expression between samples for correct analysis and interpretation of the data. From ploidy-specific expression profiles we found that the activity of cells inside the pericarp is related both to the ploidy level and their tissue location.
    Mots-clés : Cell Nucleus, CYTO, data interpretation, DNA, Plant, Endoreduplication, Fruit, Gene Expression Profiling, Lycopersicon esculentum, PF, Ploidies, RNA, Plant, RNA-Seq profiling, Sequence Analysis, RNA, Solanum lycopersicum.

  • X. Raffoux, M. Bourge, F. Dumas, O. C. Martin, et M. Falque, « High-throughput measurement of recombination rates and genetic interference in Saccharomyces cerevisiae », Yeast (Chichester, England), vol. 35, nᵒ 6, p. 431-442, 2018.

    Résumé : Allelic recombination owing to meiotic crossovers is a major driver of genome evolution, as well as a key player for the selection of high-performing genotypes in economically important species. Therefore, we developed a high-throughput and low-cost method to measure recombination rates and crossover patterning (including interference) in large populations of the budding yeast Saccharomyces cerevisiae. Recombination and interference were analysed by flow cytometry, which allows time-consuming steps such as tetrad microdissection or spore growth to be avoided. Moreover, our method can also be used to compare recombination in wild-type vs. mutant individuals or in different environmental conditions, even if the changes in recombination rates are small. Furthermore, meiotic mutants often present recombination and/or pairing defects affecting spore viability but our method does not involve growth steps and thus avoids filtering out non-viable spores.
    Mots-clés : crossing-over, CYTO, flow cytometry, fluorescent tag, meiosis, PF, yeast.

  • X. Raffoux, M. Bourge, F. Dumas, O. C. Martin, et M. Falque, « Role of Cis, Trans, and Inbreeding Effects on Meiotic Recombination in Saccharomyces cerevisiae », Genetics, vol. 210, nᵒ 4, p. 1213-1226, déc. 2018.

    Résumé : Meiotic recombination is a major driver of genome evolution by creating new genetic combinations. To probe the factors driving variability of meiotic recombination, we used a high-throughput method to measure recombination rates in hybrids between SK1 and a total of 26 Saccharomyces cerevisiae strains from different geographic origins and habitats. Fourteen intervals were monitored for each strain, covering chromosomes VI and XI entirely, and part of chromosome I. We found an average number of crossovers per chromosome ranging between 1.0 and 9.5 across strains ("domesticated" or not), which is higher than the average between 0.5 and 1.5 found in most organisms. In the different intervals analyzed, recombination showed up to ninefold variation across strains but global recombination landscapes along chromosomes varied less. We also built an incomplete diallel experiment to measure recombination rates in one region of chromosome XI in 10 different crosses involving five parental strains. Our overall results indicate that recombination rate is increasingly positively correlated with sequence similarity between homologs (i) in DNA double-strand-break-rich regions within intervals, (ii) in entire intervals, and (iii) at the whole genome scale. Therefore, these correlations cannot be explained by cis effects only. We also estimated that cis and trans effects explained 38 and 17%, respectively, of the variance of recombination rate. In addition, by using a quantitative genetics analysis, we identified an inbreeding effect that reduces recombination rate in homozygous genotypes, while other interaction effects (specific combining ability) or additive effects (general combining ability) are found to be weak. Finally, we measured significant crossover interference in some strains, and interference intensity was positively correlated with crossover number.
    Mots-clés : crossover interference, crossovers, CYTO, diversity, dna recombination, double-strand breaks, evolution, heterozygosity, interference, landscape, maize, meiosis, mismatch repair, PF, resolution, yeast.

  • S. Srisuwan, D. Sihachakr, J. Martín, J. Vallès, A. Ressayre, S. C. Brown, et S. Siljak-Yakovlev, « Change in nuclear DNA content and pollen size with polyploidisation in the sweet potato (Ipomoea batatas, Convolvulaceae) complex », Plant Biology (Stuttgart, Germany), nov. 2018.

    Résumé : Genome size evolution, and its relationships with pollen grain size, has been investigated in the sweet potato (Ipomoea batatas), an economically important crop, and closely related diploid and tetraploid species, assessing the nuclear DNA content of 22 accessions from five Ipomoea species, 10 sweet potato varieties and two outgroup taxa. Nuclear DNA amounts were determined by flow cytometry. Pollen grains have been studied at scanning and transmission electron microscopy. 2C DNA content of hexaploid I. batatas ranged over 3.12-3.29 pg, mean monoploid genome size being 0.539 pg (527 Mbp) much as for the related diploid accessions. In tetraploid species I. trifida and I. tabascana, 2C DNA content was respectively 2.07 and 2.03 pg. In the diploid species closely related to sweet potato e.g. I. ×leucantha, I. tiliacea, I. trifida, I. triloba, 2C DNA content was 1.01-1.12 pg. However, two diploid outgroup species, I. setosa and I. purpurea, were clearly different from the other diploid species with 2C of 1.47-1.49 pg; they also have larger chromosomes. The I. batatas genome presents 60.0% of AT bases. DNA content and ploidy level were positively correlated within this complex. In I. batatas and the more closely related species I. trifida, genome size and ploidy levels were correlated with pollen size. Our results allow us proposing alternative or complementary hypotheses to the one currently proposed for the formation of hexaploid Ipomoea batatas. This article is protected by copyright. All rights reserved.
    Mots-clés : Convolvulaceae, CYTO, genome size, Ipomoea batatas, PF, pollen size, polyploidy, propidium iodide flow cytometry, sweet potato.

2017


  • S. C. Brown, M. Bourge, N. Maunoury, M. Wong, M. W. Bianchi, S. Lepers-Andrzejewski, P. Besse, S. Siljak-Yakovlev, M. Dron, et B. Satiat-Jeunemaître, « DNA remodelling by Strict Partial Endoreplication in orchids, an original process in the plant kingdom », Genome Biology and Evolution, avr. 2017.

    Résumé : DNA remodelling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analysed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodelling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication. Such process is developmentally regulated in each wild species studied. Cytometry data analyses allowed us to propose a model where nuclear states 2C, 4E, 8E, etc. form a series comprising a fixed proportion, the euploid genome 2C, plus 2 to 32 additional copies of a complementary part of the genome. The fixed proportion ranged from 89% of the genome in Vanilla mexicana down to 19% in V. pompona, the lowest value for all 148 orchids reported. Insterspecific hybridisation did not suppress this phenomenon. Interestingly, this process was not observed in mass-produced epiphytes. Nucleolar volumes grow with the number of endocopies present, coherent with high transcription activity in endoreplicated nuclei. Our analyses suggest species-specific chromatin rearrangement. Towards understanding endoreplication, V. planifolia constitutes a tractable system for isolating the genomic sequences that confer an advantage via endoreplication from those that apparently suffice at diploid level.
    Mots-clés : BIOCELL, CYTO, cytogenetics, cytometry, DYNBSJ, endoreplication, genome imbalance, Genome Size, IMAGIF, MINION, PF, PHOT, Vanilla.


  • E. Dambroise, M. Simion, T. Bourquard, S. Bouffard, B. Rizzi, Y. Jaszczyszyn, M. Bourge, P. Affaticati, A. Heuzé, J. Jouralet, J. Edouard, S. Brown, C. Thermes, A. Poupon, E. Reiter, F. Sohm, F. Bourrat, et J. - S. Joly, « Postembryonic Fish Brain Proliferation Zones Exhibit Neuroepithelial-Type Gene Expression Profile: Features of Neuroepithelial Cells in Fish », STEM CELLS, 2017.

    Mots-clés : BMgif, CYTO, IMAGIF, NGS, PF, PHOT.


  • J. - A. Pedroza-García, C. Mazubert, I. del Olmo, M. Bourge, S. Domenichini, R. Bounon, Z. Tariq, E. Delannoy, M. Piñeiro, J. A. Jarillo, C. Bergounioux, M. Benhamed, et C. Raynaud, « Function of the Plant DNA Polymerase Epsilon in Replicative Stress Sensing, a Genetic Analysis », Plant Physiology, vol. 173, nᵒ 3, p. 1735-1749, 2017.

2016



  • M. Benincasa, Q. Barrière, G. Runti, O. Pierre, M. Bourge, M. Scocchi, et P. Mergaert, « Single Cell Flow Cytometry Assay for Peptide Uptake by Bacteria », BIO-PROTOCOL, vol. 6, nᵒ 23, 2016.

    Mots-clés : CYTO, IMAGIF, MICROBIO, PBI, PF.

  • C. Chaintreuil, D. Gully, C. Hervouet, P. Tittabutr, H. Randriambanona, S. C. Brown, G. P. Lewis, M. Bourge, F. Cartieaux, M. Boursot, H. Ramanankierana, A. D'Hont, N. Teaumroong, E. Giraud, et J. - F. Arrighi, « The evolutionary dynamics of ancient and recent polyploidy in the African semiaquatic species of the legume genus Aeschynomene », The New Phytologist, vol. 211, nᵒ 3, p. 1077-1091, août 2016.

    Résumé : The legume genus Aeschynomene is notable in the ability of certain semiaquatic species to develop nitrogen-fixing stem nodules. These species are distributed in two clades. In the first clade, all the species are characterized by the use of a unique Nod-independent symbiotic process. In the second clade, the species use a Nod-dependent symbiotic process and some of them display a profuse stem nodulation as exemplified in the African Aeschynomene afraspera. To facilitate the molecular analysis of the symbiotic characteristics of such legumes, we took an integrated molecular and cytogenetic approach to track occurrences of polyploidy events and to analyze their impact on the evolution of the African species of Aeschynomene. Our results revealed two rounds of polyploidy: a paleopolyploid event predating the African group and two neopolyploid speciations, along with significant chromosomal variations. Hence, we found that A. afraspera (8x) has inherited the contrasted genomic properties and the stem-nodulation habit of its parental lineages (4x). This study reveals a comprehensive picture of African Aeschynomene diversification. It notably evidences a history that is distinct from the diploid Nod-independent clade, providing clues for the identification of the specific determinants of the Nod-dependent and Nod-independent symbiotic processes, and for comparative analysis of stem nodulation.
    Mots-clés : Aeschynomene, CYTO, dysploidy, genome downsizing, IMAGIF, PF, PHOT, Polyploidy, stem nodulation, Symbiosis.


  • P. Maisonnasse, E. Bouguyon, G. Piton, A. Ezquerra, C. Urien, C. Deloizy, M. Bourge, J. - J. Leplat, G. Simon, C. Chevalier, S. Vincent-Naulleau, E. Crisci, M. Montoya, I. Schwartz-Cornil, et N. Bertho, « The respiratory DC/macrophage network at steady-state and upon influenza infection in the swine biomedical model », Mucosal Immunology, vol. 9, nᵒ 4, p. 835-849, 2016.



  • J. A. Pedroza-Garcia, S. Domenichini, C. Mazubert, M. Bourge, C. White, E. Hudik, R. Bounon, Z. Tariq, E. Delannoy, I. del Olmo, M. Piñeiro, J. A. Jarillo, C. Bergounioux, M. Benhamed, et C. Raynaud, « Role of the Polymerase ϵ sub-unit DPB2 in DNA replication, cell cycle regulation and DNA damage response in Arabidopsis », Nucleic Acids Research, p. gkw449, mai 2016.

2015



  • C. Bourbousse, I. Mestiri, G. Zabulon, M. Bourge, F. Formiggini, M. A. Koini, S. C. Brown, P. Fransz, C. Bowler, et F. Barneche, « Light signaling controls nuclear architecture reorganization during seedling establishment », Proceedings of the National Academy of Sciences, vol. 112, nᵒ 21, p. E2836-E2844, mai 2015.

    Mots-clés : CYTO, IMAGIF, PF, PHOT.


  • M. Bourge, C. Fort, M. - N. Soler, B. Satiat-Jeunemaître, et S. C. Brown, « A pulse-chase strategy combining click-EdU and photoconvertible fluorescent reporter: tracking Golgi protein dynamics during the cell cycle », New Phytologist, vol. 205, nᵒ 2, p. 938-950, 2015.

    Mots-clés : 5-ethynyl-2′-deoxyuridine (EdU), Arabidopsis, cell cycle, Cell Proliferation, Click Chemistry, Copper, CYTO, Deoxyuridine, Fluorescence, Fluorescent Dyes, fluorescent proteins, G1 subcompartments, Golgi Apparatus, Golgi synthesis, Green Fluorescent Proteins, IMAGIF, Kaede pulse-chase, Luminescent Proteins, Molecular Imaging, PF, PHOT, Plant Proteins, Plants, Genetically Modified, Protoplasts, Tobacco, tobacco (Nicotiana tabacum) BY2 cells.

  • I. Guefrachi, O. Pierre, T. Timchenko, B. Alunni, Q. Barrière, P. Czernic, J. - A. Villaécija-Aguilar, C. Verly, M. Bourge, J. Fardoux, M. Mars, E. Kondorosi, E. Giraud, et P. Mergaert, « Bradyrhizobium BclA Is a Peptide Transporter Required for Bacterial Differentiation in Symbiosis with Aeschynomene Legumes », Molecular plant-microbe interactions: MPMI, vol. 28, nᵒ 11, p. 1155-1166, nov. 2015.

    Résumé : Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen-fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called nodule-specific cysteine-rich (NCR) peptides in the symbiotic nodule cells which house the bacteroids. NCR peptides are related to antimicrobial peptides of innate immunity. They induce the endosymbionts into a differentiated, enlarged, and polyploid state. The bacterial symbionts, on their side, evolved functions for the response to the NCR peptides. Here, we identified the bclA gene of Bradyrhizobium sp. strains ORS278 and ORS285, which is required for the formation of differentiated and functional bacteroids in the nodules of the NCR peptide-producing Aeschynomene legumes. The BclA ABC transporter promotes the import of NCR peptides and provides protection against the antimicrobial activity of these peptides. Moreover, BclA can complement the role of the related BacA transporter of Sinorhizobium meliloti, which has a similar symbiotic function in the interaction with Medicago legumes.
    Mots-clés : Bacterial Proteins, Bradyrhizobium, CYTO, Fabaceae, Flow Cytometry, Genetic Complementation Test, Host-Pathogen Interactions, IMAGIF, Medicago, Membrane Transport Proteins, MICROBIO, Microscopy, Confocal, Molecular Sequence Data, Mutation, PBI, Peptides, PF, Phylogeny, Polyploidy, Root Nodules, Plant, Sinorhizobium meliloti, Symbiosis.

  • A. Hajrudinović, S. Siljak-Yakovlev, S. C. Brown, F. Pustahija, M. Bourge, D. Ballian, et F. Bogunić, « When sexual meets apomict: genome size, ploidy level and reproductive mode variation of Sorbus aria s.l. and S. austriaca (Rosaceae) in Bosnia and Herzegovina », Annals of Botany, vol. 116, nᵒ 2, p. 301-312, août 2015.

    Résumé : BACKGROUND AND AIMS: Allopolyploidy and intraspecific heteroploid crosses are associated, in certain groups, with changes in the mating system. The genus Sorbus represents an appropriate model to study the relationships between ploidy and reproductive mode variations. Diploid S. aria and tetraploid apomictic S. austriaca were screened for ploidy and mating system variations within pure and sympatric populations in order to gain insights into their putative causalities. METHODS: Flow cytometry was used to assess genome size and ploidy level among 380 S. aria s.l. and S. austriaca individuals from Bosnia and Herzegovina, with 303 single-seed flow cytometric seed screenings being performed to identify their mating system. Pollen viability and seed set were also determined. KEY RESULTS: Flow cytometry confirmed the presence of di-, tri- and tetraploid cytotype mixtures in mixed-ploidy populations of S. aria and S. austriaca. No ploidy variation was detected in single-species populations. Diploid S. aria mother plants always produced sexually originated seeds, whereas tetraploid S. austriaca as well as triploid S. aria were obligate apomicts. Tetraploid S. aria preserved sexuality in a low portion of plants. A tendency towards a balanced 2m : 1p parental genome contribution to the endosperm was shared by diploids and tetraploids, regardless of their sexual or asexual origin. In contrast, most triploids apparently tolerated endosperm imbalance. CONCLUSIONS: Coexistence of apomictic tetraploids and sexual diploids drives the production of novel polyploid cytotypes with predominantly apomictic reproductive modes. The data suggest that processes governing cytotype diversity and mating system variation in Sorbus from Bosnia and Herzegovina are probably parallel to those in other diversity hotspots of this genus. The results represent a solid contribution to knowledge of the reproduction of Sorbus and will inform future investigations of the molecular and genetic mechanisms involved in triggering and regulating cytotype diversity and alteration of reproductive modes.
    Mots-clés : Apomixis, Bosnia and Herzegovina, Cell Nucleus, CYTO, cytotypes, DNA, Plant, Endosperm, Flow Cytometry, Genome Size, Geography, IMAGIF, PF, PHOT, Ploidies, Pollen, Polyploidy, reproduction, reproduction mode, Rosaceae., Seeds, sexuality, Sorbus, Sorbus aria, Sorbus austriaca.


  • T. Jégu, S. Domenichini, T. Blein, F. Ariel, A. Christ, S. - K. Kim, M. Crespi, S. Boutet-Mercey, G. Mouille, M. Bourge, H. Hirt, C. Bergounioux, C. Raynaud, et M. Benhamed, « A SWI/SNF Chromatin Remodelling Protein Controls Cytokinin Production through the Regulation of Chromatin Architecture », PLOS ONE, vol. 10, nᵒ 10, p. e0138276, oct. 2015.

    Mots-clés : Alkyl and Aryl Transferases, Arabidopsis, Arabidopsis Proteins, Carrier Proteins, cell cycle, Chromatin, Chromatin Assembly and Disassembly, Chromosomal Proteins, Non-Histone, CYTO, Cytokinins, DNA, Plant, Epigenesis, Genetic, Genetic Loci, Histones, IMAGIF, Meristem, PF.


  • T. - P. Vu Manh, J. Elhmouzi-Younes, C. Urien, S. Ruscanu, L. Jouneau, M. Bourge, M. Moroldo, G. Foucras, H. Salmon, H. Marty, P. Quéré, N. Bertho, P. Boudinot, M. Dalod, et I. Schwartz-Cornil, « Defining Mononuclear Phagocyte Subset Homology Across Several Distant Warm-Blooded Vertebrates Through Comparative Transcriptomics », Frontiers in Immunology, vol. 6, juin 2015.

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Microscopie Electronique

2018


  • M. Blondeau, M. Sachse, C. Boulogne, C. Gillet, J. - M. Guigner, F. Skouri-Panet, M. Poinsot, C. Ferard, J. Miot, et K. Benzerara, « Amorphous Calcium Carbonate Granules Form Within an Intracellular Compartment in Calcifying Cyanobacteria », Frontiers in Microbiology, vol. 9, p. 1768, 2018.

    Résumé : The recent discovery of cyanobacteria forming intracellular amorphous calcium carbonate (ACC) has challenged the former paradigm suggesting that cyanobacteria-mediated carbonatogenesis was exclusively extracellular. Yet, the mechanisms of intracellular biomineralization in cyanobacteria and in particular whether this takes place within an intracellular microcompartment, remain poorly understood. Here, we analyzed six cyanobacterial strains forming intracellular ACC by transmission electron microscopy. We tested two different approaches to preserve as well as possible the intracellular ACC inclusions: (i) freeze-substitution followed by epoxy embedding and room-temperature ultramicrotomy and (ii) high-pressure freezing followed by cryo-ultramicrotomy, usually referred to as cryo-electron microscopy of vitreous sections (CEMOVIS). We observed that the first method preserved ACC well in 500-nm-thick sections but not in 70-nm-thick sections. However, cell ultrastructures were difficult to clearly observe in the 500-nm-thick sections. In contrast, CEMOVIS provided a high preservation quality of bacterial ultrastructures, including the intracellular ACC inclusions in 50-nm-thick sections. ACC inclusions displayed different textures, suggesting varying brittleness, possibly resulting from different hydration levels. Moreover, an electron dense envelope of ∼2.5 nm was systematically observed around ACC granules in all studied cyanobacterial strains. This envelope may be composed of a protein shell or a lipid monolayer, but not a lipid bilayer as usually observed in other bacteria forming intracellular minerals. Overall, this study evidenced that ACC inclusions formed and were stabilized within a previously unidentified bacterial microcompartment in some species of cyanobacteria.
    Mots-clés : amorphous calcium carbonate, bacterial microcompartment, biomineralization, ca, calcification, carboxysome, CEMOVIS, MET, PF.

2017



  • J. Marion, R. Le Bars, B. Satiat-Jeunemaitre, et C. Boulogne, « Optimizing CLEM protocols for plants cells: GMA embedding and cryosections as alternatives for preservation of GFP fluorescence in Arabidopsis roots », Journal of Structural Biology, 2017.

    Mots-clés : Arabidopsis, BIOCELL, Correlative microscopy, DYNBSJ, GFP, GMA resin, IMAGIF, MET, PF, PHOT, Tokuyasu, Transmission electron microscopy.

  • Y. Wu, V. Pons, A. Goudet, L. Panigai, A. Fischer, J. - A. Herweg, S. Kali, R. A. Davey, J. Laporte, C. Bouclier, R. Yousfi, C. Aubenque, G. Merer, E. Gobbo, R. Lopez, C. Gillet, S. Cojean, M. R. Popoff, P. Clayette, R. Le Grand, C. Boulogne, N. Tordo, E. Lemichez, P. M. Loiseau, T. Rudel, D. Sauvaire, J. - C. Cintrat, D. Gillet, et J. Barbier, « ABMA, a small molecule that inhibits intracellular toxins and pathogens by interfering with late endosomal compartments », Scientific Reports, vol. 7, nᵒ 1, p. 15567, nov. 2017.

    Résumé : Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identified the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efficiently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.
    Mots-clés : MET, PF.
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Microscopie Photonique

2019


  • R. Le Bars, M. W. Bianchi, et C. Lefebvre, « Three-Dimensional Surface Rendering of ESCRT Proteins Microscopy Data Using UCSF Chimera Software », Methods in Molecular Biology (Clifton, N.J.), vol. 1998, p. 149-161, 2019.

    Résumé : Visualization of subcellular localization of ESCRT proteins and their interactions with different cellular compartments are critical to understand their function. This approach requires the generation of an important amount of 3D fluorescence microscopy data that is not always easy to visualize and apprehend.We describe a step-by-step protocol for 3D surface rendering of confocal microscopy acquisitions using the free software UCSF-Chimera, generating snapshots and animations to facilitate analysis and presentation of subcellular localization data.
    Mots-clés : 3D animation, 3D fluorescence confocal microscopy, BIOCELL, ESCRT, MINION, OTOFAG, PF, PHOT, Surface rendering, UCSF Chimera.

2018



  • T. Avin-Wittenberg, F. Baluška, P. V. Bozhkov, P. H. Elander, A. R. Fernie, G. Galili, A. Hassan, D. Hofius, E. Isono, R. Le Bars, C. Masclaux-Daubresse, E. A. Minina, H. Peled-Zehavi, N. S. Coll, L. M. Sandalio, B. Satiat-Jeunemaitre, A. Sirko, P. S. Testillano, et H. Batoko, « Autophagy-related approaches for improving nutrient use efficiency and crop yield protection », Journal of Experimental Botany, vol. 69, nᵒ 6, p. 1335-1353, mars 2018.

    Mots-clés : BIOCELL, CYTO, DYNBSJ, PF, PHOT.

  • T. Avin-Wittenberg, F. Baluška, P. V. Bozhkov, P. H. Elander, A. R. Fernie, G. Galili, A. Hassan, D. Hofius, E. Isono, R. Le Bars, C. Masclaux-Daubresse, E. A. Minina, H. Peled-Zehavi, N. S. Coll, L. M. Sandalio, B. Satiat-Jeunemaitre, A. Sirko, P. S. Testillano, et H. Batoko, « Corrigendum: Autophagy-related approaches for improving nutrient use efficiency and crop yield protection », Journal of Experimental Botany, vol. 69, nᵒ 12, p. 3173, mai 2018.

    Mots-clés : BIOCELL, CYTO, DYNBSJ, PF, PHOT.

  • J. Marion, R. Le Bars, L. Besse, H. Batoko, et B. Satiat-Jeunemaitre, « Multiscale and Multimodal Approaches to Study Autophagy in Model Plants », Cells, vol. 7, nᵒ 1, janv. 2018.

    Résumé : Autophagy is a catabolic process used by eukaryotic cells to maintain or restore cellular and organismal homeostasis. A better understanding of autophagy in plant biology could lead to an improvement of the recycling processes of plant cells and thus contribute, for example, towards reducing the negative ecological consequences of nitrogen-based fertilizers in agriculture. It may also help to optimize plant adaptation to adverse biotic and abiotic conditions through appropriate plant breeding or genetic engineering to incorporate useful traits in relation to this catabolic pathway. In this review, we describe useful protocols for studying autophagy in the plant cell, taking into account some specificities of the plant model.
    Mots-clés : Arabidopsis, autophagosome, Autophagy, autophagy assays, BIOCELL, CYTO, DYNBSJ, methods, PHOT, plant cells, Tobacco.

2017


  • L. Becker, S. Bellow, V. Carré, G. Latouche, A. Poutaraud, D. Merdinoglu, S. C. Brown, Z. G. Cerovic, et P. Chaimbault, « Correlative Analysis of Fluorescent Phytoalexins by Mass Spectrometry Imaging and Fluorescence Microscopy in Grapevine Leaves », Analytical Chemistry, juin 2017.

    Résumé : Plant response to their environment stresses is a complex mechanism involving secondary metabolites. Stilbene phytoalexins, namely resveratrol, pterostilbene, piceids and viniferins play a key role in grapevine (Vitis vinifera) leaf defense. Despite their well-established qualities, conventional analyses such as HPLC-DAD or LC-MS lose valuable information on metabolite localization during the extraction process. To overcome this issue, a correlative analysis combining mass spectroscopy imaging (MSI) and fluorescence imaging was developed to localize in situ stilbenes on the same stressed grapevine leaves. High-resolution images of the stilbene fluorescence provided by macroscopy were supplemented by specific distributions and structural information concerning resveratrol, pterostilbene, and piceids obtained by MSI. The two imaging techniques led to consistent and complementary data on the stilbene spatial distribution for the two stresses addressed: UV-C irradiation and infection by Plasmopara viticola. Results emphasize that grapevine leaves react differently depending on the stress. A rather uniform synthesis of stilbenes is induced after UV-C irradiation, whereas a more localized synthesis of stilbenes in stomata guard cells and cell walls is induced by P. viticola infection. Finally, this combined imaging approach could be extended to map phytoalexins of various plant tissues with resolution approaching the cellular level.
    Mots-clés : IMAGIF, PF, PHOT.

  • S. C. Brown, M. Bourge, N. Maunoury, M. Wong, M. W. Bianchi, S. Lepers-Andrzejewski, P. Besse, S. Siljak-Yakovlev, M. Dron, et B. Satiat-Jeunemaître, « DNA remodelling by Strict Partial Endoreplication in orchids, an original process in the plant kingdom », Genome Biology and Evolution, avr. 2017.

    Résumé : DNA remodelling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analysed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodelling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication. Such process is developmentally regulated in each wild species studied. Cytometry data analyses allowed us to propose a model where nuclear states 2C, 4E, 8E, etc. form a series comprising a fixed proportion, the euploid genome 2C, plus 2 to 32 additional copies of a complementary part of the genome. The fixed proportion ranged from 89% of the genome in Vanilla mexicana down to 19% in V. pompona, the lowest value for all 148 orchids reported. Insterspecific hybridisation did not suppress this phenomenon. Interestingly, this process was not observed in mass-produced epiphytes. Nucleolar volumes grow with the number of endocopies present, coherent with high transcription activity in endoreplicated nuclei. Our analyses suggest species-specific chromatin rearrangement. Towards understanding endoreplication, V. planifolia constitutes a tractable system for isolating the genomic sequences that confer an advantage via endoreplication from those that apparently suffice at diploid level.
    Mots-clés : BIOCELL, CYTO, cytogenetics, cytometry, DYNBSJ, endoreplication, genome imbalance, Genome Size, IMAGIF, MINION, PF, PHOT, Vanilla.


  • E. Dambroise, M. Simion, T. Bourquard, S. Bouffard, B. Rizzi, Y. Jaszczyszyn, M. Bourge, P. Affaticati, A. Heuzé, J. Jouralet, J. Edouard, S. Brown, C. Thermes, A. Poupon, E. Reiter, F. Sohm, F. Bourrat, et J. - S. Joly, « Postembryonic Fish Brain Proliferation Zones Exhibit Neuroepithelial-Type Gene Expression Profile: Features of Neuroepithelial Cells in Fish », STEM CELLS, 2017.

    Mots-clés : BMgif, CYTO, IMAGIF, NGS, PF, PHOT.


  • J. Marion, R. Le Bars, B. Satiat-Jeunemaitre, et C. Boulogne, « Optimizing CLEM protocols for plants cells: GMA embedding and cryosections as alternatives for preservation of GFP fluorescence in Arabidopsis roots », Journal of Structural Biology, 2017.

    Mots-clés : Arabidopsis, BIOCELL, Correlative microscopy, DYNBSJ, GFP, GMA resin, IMAGIF, MET, PF, PHOT, Tokuyasu, Transmission electron microscopy.

  • J. Nikolic, R. Le Bars, Z. Lama, N. Scrima, C. Lagaudrière-Gesbert, Y. Gaudin, et D. Blondel, « Negri bodies are viral factories with properties of liquid organelles », Nature Communications, vol. 8, nᵒ 1, p. 58, juill. 2017.

    Résumé : Replication of Mononegavirales occurs in viral factories which form inclusions in the host-cell cytoplasm. For rabies virus, those inclusions are called Negri bodies (NBs). We report that NBs have characteristics similar to those of liquid organelles: they are spherical, they fuse to form larger structures, and they disappear upon hypotonic shock. Their liquid phase is confirmed by FRAP experiments. Live-cell imaging indicates that viral nucleocapsids are ejected from NBs and transported along microtubules to form either new virions or secondary viral factories. Coexpression of rabies virus N and P proteins results in cytoplasmic inclusions recapitulating NBs properties. This minimal system reveals that an intrinsically disordered domain and the dimerization domain of P are essential for Negri bodies-like structures formation. We suggest that formation of liquid viral factories by phase separation is common among Mononegavirales and allows specific recruitment and concentration of viral proteins but also the escape to cellular antiviral response.Negative strand RNA viruses, such as rabies virus, induce formation of cytoplasmic inclusions for genome replication. Here, Nikolic et al. show that these so-called Negri bodies (NBs) have characteristics of liquid organelles and they identify the minimal protein domains required for NB formation.
    Mots-clés : IMAGIF, PF, PHOT, RHABDO, VIRO.


  • P. Pétriacq, L. de Bont, L. Genestout, J. Hao, C. Laureau, I. Florez-Sarasa, T. Rzigui, G. Queval, F. Gilard, C. Mauve, F. Guérard, M. Lamothe-Sibold, J. Marion, C. Fresneau, S. Brown, A. Danon, A. Krieger-Liszkay, R. Berthomé, M. Ribas-Carbo, G. Tcherkez, G. Cornic, B. Pineau, B. Gakière, et R. De Paepe, « Photoperiod Affects the Phenotype of Mitochondrial Complex I Mutants », Plant Physiology, vol. 173, nᵒ 1, p. 434-455, 2017.

    Mots-clés : B3S, BIOCELL, DYNBSJ, IMAGIF, MROP, PF, PHOT.


  • Z. M. Song, L. Bouchab, E. Hudik, R. Le Bars, O. Nüsse, et S. Dupré-Crochet, « Phosphoinositol 3-phosphate acts as a timer for reactive oxygen species production in the phagosome », Journal of Leukocyte Biology, p. jlb.1A0716-305R, janv. 2017.

2016


  • C. Chaintreuil, D. Gully, C. Hervouet, P. Tittabutr, H. Randriambanona, S. C. Brown, G. P. Lewis, M. Bourge, F. Cartieaux, M. Boursot, H. Ramanankierana, A. D'Hont, N. Teaumroong, E. Giraud, et J. - F. Arrighi, « The evolutionary dynamics of ancient and recent polyploidy in the African semiaquatic species of the legume genus Aeschynomene », The New Phytologist, vol. 211, nᵒ 3, p. 1077-1091, août 2016.

    Résumé : The legume genus Aeschynomene is notable in the ability of certain semiaquatic species to develop nitrogen-fixing stem nodules. These species are distributed in two clades. In the first clade, all the species are characterized by the use of a unique Nod-independent symbiotic process. In the second clade, the species use a Nod-dependent symbiotic process and some of them display a profuse stem nodulation as exemplified in the African Aeschynomene afraspera. To facilitate the molecular analysis of the symbiotic characteristics of such legumes, we took an integrated molecular and cytogenetic approach to track occurrences of polyploidy events and to analyze their impact on the evolution of the African species of Aeschynomene. Our results revealed two rounds of polyploidy: a paleopolyploid event predating the African group and two neopolyploid speciations, along with significant chromosomal variations. Hence, we found that A. afraspera (8x) has inherited the contrasted genomic properties and the stem-nodulation habit of its parental lineages (4x). This study reveals a comprehensive picture of African Aeschynomene diversification. It notably evidences a history that is distinct from the diploid Nod-independent clade, providing clues for the identification of the specific determinants of the Nod-dependent and Nod-independent symbiotic processes, and for comparative analysis of stem nodulation.
    Mots-clés : Aeschynomene, CYTO, dysploidy, genome downsizing, IMAGIF, PF, PHOT, Polyploidy, stem nodulation, Symbiosis.


  • E. Galli, M. Poidevin, R. Le Bars, J. - M. Desfontaines, L. Muresan, E. Paly, Y. Yamaichi, et F. - X. Barre, « Cell division licensing in the multi-chromosomal Vibrio cholerae bacterium », Nature Microbiology, vol. 1, nᵒ 9, p. 16094, juin 2016.

2015



  • C. Bourbousse, I. Mestiri, G. Zabulon, M. Bourge, F. Formiggini, M. A. Koini, S. C. Brown, P. Fransz, C. Bowler, et F. Barneche, « Light signaling controls nuclear architecture reorganization during seedling establishment », Proceedings of the National Academy of Sciences, vol. 112, nᵒ 21, p. E2836-E2844, mai 2015.

    Mots-clés : CYTO, IMAGIF, PF, PHOT.


  • M. Bourge, C. Fort, M. - N. Soler, B. Satiat-Jeunemaître, et S. C. Brown, « A pulse-chase strategy combining click-EdU and photoconvertible fluorescent reporter: tracking Golgi protein dynamics during the cell cycle », New Phytologist, vol. 205, nᵒ 2, p. 938-950, 2015.

    Mots-clés : 5-ethynyl-2′-deoxyuridine (EdU), Arabidopsis, cell cycle, Cell Proliferation, Click Chemistry, Copper, CYTO, Deoxyuridine, Fluorescence, Fluorescent Dyes, fluorescent proteins, G1 subcompartments, Golgi Apparatus, Golgi synthesis, Green Fluorescent Proteins, IMAGIF, Kaede pulse-chase, Luminescent Proteins, Molecular Imaging, PF, PHOT, Plant Proteins, Plants, Genetically Modified, Protoplasts, Tobacco, tobacco (Nicotiana tabacum) BY2 cells.

  • A. Hajrudinović, S. Siljak-Yakovlev, S. C. Brown, F. Pustahija, M. Bourge, D. Ballian, et F. Bogunić, « When sexual meets apomict: genome size, ploidy level and reproductive mode variation of Sorbus aria s.l. and S. austriaca (Rosaceae) in Bosnia and Herzegovina », Annals of Botany, vol. 116, nᵒ 2, p. 301-312, août 2015.

    Résumé : BACKGROUND AND AIMS: Allopolyploidy and intraspecific heteroploid crosses are associated, in certain groups, with changes in the mating system. The genus Sorbus represents an appropriate model to study the relationships between ploidy and reproductive mode variations. Diploid S. aria and tetraploid apomictic S. austriaca were screened for ploidy and mating system variations within pure and sympatric populations in order to gain insights into their putative causalities. METHODS: Flow cytometry was used to assess genome size and ploidy level among 380 S. aria s.l. and S. austriaca individuals from Bosnia and Herzegovina, with 303 single-seed flow cytometric seed screenings being performed to identify their mating system. Pollen viability and seed set were also determined. KEY RESULTS: Flow cytometry confirmed the presence of di-, tri- and tetraploid cytotype mixtures in mixed-ploidy populations of S. aria and S. austriaca. No ploidy variation was detected in single-species populations. Diploid S. aria mother plants always produced sexually originated seeds, whereas tetraploid S. austriaca as well as triploid S. aria were obligate apomicts. Tetraploid S. aria preserved sexuality in a low portion of plants. A tendency towards a balanced 2m : 1p parental genome contribution to the endosperm was shared by diploids and tetraploids, regardless of their sexual or asexual origin. In contrast, most triploids apparently tolerated endosperm imbalance. CONCLUSIONS: Coexistence of apomictic tetraploids and sexual diploids drives the production of novel polyploid cytotypes with predominantly apomictic reproductive modes. The data suggest that processes governing cytotype diversity and mating system variation in Sorbus from Bosnia and Herzegovina are probably parallel to those in other diversity hotspots of this genus. The results represent a solid contribution to knowledge of the reproduction of Sorbus and will inform future investigations of the molecular and genetic mechanisms involved in triggering and regulating cytotype diversity and alteration of reproductive modes.
    Mots-clés : Apomixis, Bosnia and Herzegovina, Cell Nucleus, CYTO, cytotypes, DNA, Plant, Endosperm, Flow Cytometry, Genome Size, Geography, IMAGIF, PF, PHOT, Ploidies, Pollen, Polyploidy, reproduction, reproduction mode, Rosaceae., Seeds, sexuality, Sorbus, Sorbus aria, Sorbus austriaca.
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Cytométrie en flux

2019
E. Bordet, M. Frétaud, E. Crisci, E. Bouguyon, S. Rault, J. Pezant, A. Pleau, P. Renson, E. Giuffra, T. Larcher, M. Bourge, O. Bourry, O. Boulesteix, (...)

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Microscopie Electronique

2018
M. Blondeau, M. Sachse, C. Boulogne, C. Gillet, J. - M. Guigner, F. Skouri-Panet, M. Poinsot, C. Ferard, J. Miot, et K. Benzerara, « Amorphous Calcium (...)

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Microscopie photonique

2019
R. Le Bars, M. W. Bianchi, et C. Lefebvre, « Three-Dimensional Surface Rendering of ESCRT Proteins Microscopy Data Using UCSF Chimera Software », Methods in (...)

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Posters

Posters
Correlative microscopy to explore endomembrane system in plant cells. C. Gillet, R. Le Borgne, J. Marion, C. Boulogne, R. Lebars, B. Satiat-Jeunemaitre. 3D Electron Microscopy : From (...)

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