Localization and chemical forms of cadmium in plant samples by combining analytical electron microscopy and X-ray spectromicroscopy

International audienceCadmium (Cd) is a metal of high toxicity for plants. Resolving its distribution and speciation in plants is essential for understanding the mechanisms involved in Cd tolerance, trafficking and accumulation. The model plant Arabidopsis thaliana was exposed to cadmium under controlled conditions. Elemental distributions in the roots and in the leaves were determined using scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX), and synchrotron-based micro X-ray fluorescence (μ-XRF), which offers a better sensitivity. The chemical form(s) of cadmium was investigated using Cd LIII-edge (3538 eV) micro X-ray absorption near edge structure (μ-XANES) spectroscopy. Plant μ-XANES spectra were fitted by linear combination of Cd reference spectra. Biological sample preparation and conditioning is a critical point because of possible artifacts. In this work we compared freeze-dried samples analyzed at ambient temperature and frozen hydrated samples analyzed at −170 °C. Our results suggest that in the roots Cd is localized in vascular bundles, and coordinated to S ligands. In the leaves, trichomes (epidermal hairs) represent the main compartment of Cd accumulation. In these specialized cells, μ-XANES results show that the majority of Cd is bound to O/N ligands likely provided by the cell wall, and a minor fraction could be bound to S-containing ligands. No significant difference in Cd speciation was observed between freeze-dried and frozen hydrated samples. This work illustrates the interest and the sensitivity of Cd LIII-edge XANES spectroscopy, which is applied here for the first time to plant samples. Combining μ-XRF and Cd LIII-edge μ-XANES spectroscopy offers promising tools to study Cd storage and trafficking mechanisms in plants and other biological samples

Caractérisation du protéome vascuolaire de la plante modèle Arabidopsis thaliana et étude de son rôle dans la détoxication du cadmium

Afin de mieux comprendre les mécanismes du trafic cellulaire, les processus de transport des substrats vacuolaires à travers le tonoplaste, le stockage des métabolites et leur dégradation, une analyse globale et exhaustive du protéome vacuolaire d'Arabidopsis thaliana a été réalisée. La connaissance de la localisation subcellulaire des protéines permet de mieux comprendre la fonction des organelles et la compartimentation du métabolisme des plantes. Mais la description précise du protéome d'un organite nécessite d'identifier clairement les véritables protéines résidantes du compartiment étudié. Une tâche si précise est complexe puisqu'elle nécessite la mise en place d'une préparation d'organites purs et homogènes. Pour y parvenir, un protocole de purification de vacuoles à partir de protoplastes isolés de cellules en culture sur un gradient de densité de Ficoll a été amélioré. La combinaison de plusieurs approches de protéomique a permis d'identifier les protéines présentes dans les fractions vacuolaires soluble et membranaire de façon quantitative et fonctionnelle. Les différentes approches ont ainsi mis en évidence des associations et mécanismes moléculaires complexes qui régissent les différentes activités vacuolaires. Cette protéothèque de référence constitue une base pour étudier la dynamique du protéome vacuolaire en réponse à plusieurs stress incluant les métaux lourds. Plusieurs méthodes sans a priori et ciblée ont été proposé afin d'étudier l'impact du cadmium sur la vacuole, ce compartiment cellulaire clé de la détoxication.To better understand the mechanisms governing cellular traffic, transport process of substrates across the tonoplast, storage of various metabolites and their ultimate degradation, a comprehensive and thorough analysis of Arabidopsis thaliana vacuolar proteome was performed. Protein subcellular localization knowledge is an important step toward assigning functions of organelles and plant metabolism compartmentation. But confident description of proteome organelle content requires clear identification of the true resident proteins of the studied compartment. This task involves pitfalls and requires that either organelle preparations are free of contaminants or that techniques are used to discriminate between genuine organelle residents and contaminating proteins. To achieve this, vacuoles purification protocol from protoplasts on a Ficoll density gradient has been improved. The combination of several proteomic approaches attempt to present soluble and membrane vacuolar proteins in a quantitative and functional manner. Different approaches have thus shown associations and complex molecular mechanisms that govern the various vacuolar activities. The constitute proteins library provides references to study the vacuolar proteome dynamics in response to different stresses including heavy metals. Many methods without a priori or targeted were proposed to study the impact of cadmium on the vacuole, the key cell compartment of detoxification. Proteomics provides powerful tools for characterizing the protein contents of vacuoles during cadmium stress.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Neoisoptera repeatedly colonised Madagascar after the Middle Miocene climatic optimum

Madagascar is home to many endemic plant and animal species owing to its ancient isolation from other landmasses. This unique fauna includes several lineages of termites, a group of insects known for their key role in organic matter decomposition in many terrestrial ecosystems. How and when termites colonised Madagascar remains unknown. In this study, we used 601 mitochondrial genomes, 93 of which were generated from Malagasy samples, to infer the global historical biogeography of Neoisoptera, a lineage containing more than 80% of described termite species. Our results indicate that Neoisoptera colonised Madagascar between 7 and 10 times independently during the Miocene, between 8.4 and 16.6 Ma (95% HPD: 6.1–19.9 Ma). This timing matches that of the colonization of Australia by Neoisoptera. Furthermore, the taxonomic composition of the Neoisopteran fauna of Madagascar and Australia are strikingly similar, with Madagascar harbouring an additional two lineages absent from Australia. Therefore, akin to Australia, Neoisoptera colonised Madagascar during the global expansion of grasslands, possibly helped by the ecological opportunities arising from the spread of this new biome.journal articl

Ribosomal RNA 2′O-methylation as a novel layer of inter-tumour heterogeneity in breast cancer

International audienceRecent epitranscriptomics studies unravelled that ribosomal RNA (rRNA) 2′O-methylation is an additional layer of gene expression regulation highlighting the ribosome as a novel actor of translation control. However, this major finding lies on evidences coming mainly, if not exclusively, from cellular models. Using the innovative next-generation RiboMeth-seq technology, we established the first rRNA 2′O-methylation landscape in 195 primary human breast tumours. We uncovered the existence of compulsory/stable sites, which show limited inter-patient variability in their 2′O-methylation level, which map on functionally important sites of the human ribosome structure and which are surrounded by variable sites found from the second nucleotide layers. Our data demonstrate that some positions within the rRNA molecules can tolerate absence of 2′O-methylation in tumoral and healthy tissues. We also reveal that rRNA 2′O-methylation exhibits intra- and inter-patient variability in breast tumours. Its level is indeed differentially associated with breast cancer subtype and tumour grade. Altogether, our rRNA 2′O-methylation profiling of a large-scale human sample collection provides the first compelling evidence that ribosome variability occurs in humans and suggests that rRNA 2′O-methylation might represent a relevant element of tumour biology useful in clinic. This novel variability at molecular level offers an additional layer to capture the cancer heterogeneity and associates with specific features of tumour biology thus offering a novel targetable molecular signature in cancer

Disease Progression in MRL/lpr Lupus-Prone Mice Is Reduced by NCS 613, a Specific Cyclic Nucleotide Phosphodiesterase Type 4 (PDE4) Inhibitor

Systemic lupus erythematosus is a polymorphic and multigenic inflammatory autoimmune disease. Cyclic AMP (cAMP) modulates inflammation and the inhibition of cyclic nucleotide phosphodiesterase type 4 (PDE4), which specifically hydrolyzes cAMP, inhibits TNFα secretion. This study was aimed at investigating the evolution of PDE activity and expression levels during the course of the disease in MRL/lpr lupus-prone mice, and to evaluate in these mice the biological and clinical effects of treatments with pentoxifylline, denbufylline and NCS 613 PDE inhibitors. This study reveals that compared to CBA/J control mice, kidney PDE4 activity of MRL/lpr mice increases with the disease progression. Furthermore, it showed that the most potent and selective PDE4 inhibitor NCS 613 is also the most effective molecule in decreasing proteinuria and increasing survival rate of MRL/lpr mice. NCS 613 is a potent inhibitor, which is more selective for the PDE4C subtype (IC50 = 1.4 nM) than the other subtypes (PDE4A, IC50 = 44 nM; PDE4B, IC50 = 48 nM; and PDE4D, IC50 = 14 nM). Interestingly, its affinity for the High Affinity Rolipram Binding Site is relatively low (Ki = 148 nM) in comparison to rolipram (Ki = 3 nM). Finally, as also observed using MRL/lpr peripheral blood lymphocytes (PBLs), NCS 613 inhibits basal and LPS-induced TNFα secretion from PBLs of lupus patients, suggesting a therapeutic potential of NCS 613 in systemic lupus. This study reveals that PDE4 represent a potential therapeutic target in lupus disease

Identification of six new susceptibility loci for invasive epithelial ovarian cancer.

Genome-wide association studies (GWAS) have identified 12 epithelial ovarian cancer (EOC) susceptibility alleles. The pattern of association at these loci is consistent in BRCA1 and BRCA2 mutation carriers who are at high risk of EOC. After imputation to 1000 Genomes Project data, we assessed associations of 11 million genetic variants with EOC risk from 15,437 cases unselected for family history and 30,845 controls and from 15,252 BRCA1 mutation carriers and 8,211 BRCA2 mutation carriers (3,096 with ovarian cancer), and we combined the results in a meta-analysis. This new study design yielded increased statistical power, leading to the discovery of six new EOC susceptibility loci. Variants at 1p36 (nearest gene, WNT4), 4q26 (SYNPO2), 9q34.2 (ABO) and 17q11.2 (ATAD5) were associated with EOC risk, and at 1p34.3 (RSPO1) and 6p22.1 (GPX6) variants were specifically associated with the serous EOC subtype, all with P < 5 × 10(-8). Incorporating these variants into risk assessment tools will improve clinical risk predictions for BRCA1 and BRCA2 mutation carriers.COGS project is funded through a European Commission's Seventh Framework Programme grant (agreement number 223175 ] HEALTH ]F2 ]2009 ]223175). The CIMBA data management and data analysis were supported by Cancer Research.UK grants 12292/A11174 and C1287/A10118. The Ovarian Cancer Association Consortium is supported by a grant from the Ovarian Cancer Research Fund thanks to donations by the family and friends of Kathryn Sladek Smith (PPD/RPCI.07). The scientific development and funding for this project were in part supported by the US National Cancer Institute GAME ]ON Post ]GWAS Initiative (U19 ]CA148112). This study made use of data generated by the Wellcome Trust Case Control consortium. Funding for the project was provided by the Wellcome Trust under award 076113. The results published here are in part based upon data generated by The Cancer Genome Atlas Pilot Project established by the National Cancer Institute and National Human Genome Research Institute (dbGap accession number phs000178.v8.p7). The cBio portal is developed and maintained by the Computational Biology Center at Memorial Sloan ] Kettering Cancer Center. SH is supported by an NHMRC Program Grant to GCT. Details of the funding of individual investigators and studies are provided in the Supplementary Note. This study made use of data generated by the Wellcome Trust Case Control consortium, funding for which was provided by the Wellcome Trust under award 076113. The results published here are, in part, based upon data generated by The Cancer Genome Atlas Pilot Project established by the National Cancerhttp://dx.doi.org/10.1038/ng.3185This is the Author Accepted Manuscript of 'Identification of six new susceptibility loci for invasive epithelial ovarian cancer' which was published in Nature Genetics 47, 164–171 (2015) © Nature Publishing Group - content may only be used for academic research

Clinique de la famille

La clinique de la famille est éclairée par les apports de la psychologie clinique, de la psychiatrie, de la psychanalyse, de l’éthologie, de l’anthropologie, de l’approche écosystémique. La sexualité, la parentalité, la fraternité sont l’enjeu de conflits, internes et externes, qui surgissent des interférences entre la différenciation et l’affirmation personnelles et les pressions familiales et sociales. La diversification des thérapies familiales contemporaines permet d’ajuster les réponses cliniques à apporter aux demandes personnelles, familiales et sociales liées à la multiplicité des symptômes et des formes de souffrance rencontrés à tous les âges de l’existence