The Arabidopsis TUMOR PRONE5 (TUP5) gene encodes an acetylornithine aminotransferase required for arginine biosynthesis and root meristem maintenance in blue light.

Arginine is an essential amino acid necessary for protein synthesis and is also a nitrogen storage compound. The genes encoding the enzymes of arginine biosynthesis in plants are not well characterized and have mainly been predicted from homologies to bacterial and fungal genes. We report the cloning and characterization of the TUMOR PRONE5 (TUP5) gene of Arabidopsis (Arabidopsis thaliana) encoding an acetylornithine aminotransferase (ACOAT), catalyzing the fourth step of arginine biosynthesis. The free arginine content was strongly reduced in the chemically induced recessive mutant tup5-1, root growth was restored by supplementation with arginine and its metabolic precursors, and a yeast (Saccharomyces cerevisiae) ACOAT mutant was complemented by TUP5. Two null alleles of TUP5 caused a reduced viability of gametes and embryo lethality, possibly caused by insufficient Arg supply from maternal tissue. TUP5 expression is positively regulated by light, and a TUP5-green fluorescent protein was localized in chloroplasts. tup5-1 has a unique light-dependent short root phenotype. Roots of light-grown tup5-1 seedlings switch from indeterminate growth to determinate growth with arresting cell production and an exhausted root apical meristem. The inhibitory activity was specific for blue light, and the inhibiting light was perceived by the root. Thus, tup5-1 reveals a novel role of amino acids and blue light in regulating root meristem function

Diagnostic accuracy of ultrasonography, MRI and MR arthrography in the characterisation of rotator cuff disorders: A systematic review and meta-analysis

Background Different diagnostic imaging modalities, such as ultrasonography (US), MRI, MR arthrography (MRA) are commonly used for the characterisation of rotator cuff (RC) disorders. Since the most recent systematic reviews on medical imaging, multiple diagnostic studies have been published, most using more advanced technological characteristics. The first objective was to perform a meta-analysis on the diagnostic accuracy of medical imaging for characterisation of RC disorders. Since US is used at the point of care in environments such as sports medicine, a secondary analysis assessed accuracy by radiologists and nonradiologists. Methods A systematic search in three databases was conducted. Two raters performed data extraction and evaluation of risk of bias independently, and agreement was achieved by consensus. Hierarchical summary receiver-operating characteristic package was used to calculate pooled estimates of included diagnostic studies. Results Diagnostic accuracy of US, MRI and MRA in the characterisation of full-thickness RC tears was high with overall estimates of sensitivity and specificity over 0.90. As for partial RC tears and tendinopathy, overall estimates of specificity were also high (\u3e0.90), while sensitivity was lower (0.67â 0.83). Diagnostic accuracy of US was similar whether a trained radiologist, sonographer or orthopaedist performed it. Conclusions Our results show the diagnostic accuracy of US, MRI and MRA in the characterisation of fullthickness RC tears. Since full thickness tear constitutes a key consideration for surgical repair, this is an important characteristic when selecting an imaging modality for RC disorder. When considering accuracy, cost, and safety, US is the best option

Funktionelle Charakterisierung des TUP5-Gens von Arabidopsis thaliana

Arginine is one of 20 standard amino acids necessary for the formation of peptides and proteins. It is also used as a nitrogen storage compound in seeds. Furthermore, arginine is the precursor of polyamines and nitric oxide which play an important role in many developmental processes and the response to various environmental stresses. Plant amino acid pathways have for a long time been mainly deduced from studies in bacteria and fungi. In this work the first conclusive study on an arginine biosynthetic Arabidopsis mutant is described. The EMS mutant tup5-1 (tumor prone 5-1) was found in a screen for Arabidopsis mutants of which hypocotyl and root explants were cultivated on medium containing low auxin and cytokinin concentrations. The phytohormone concentrations were under the threshold of callus induction in the wild type, while the tumor prone mutants produced calli (Riefler, 2001). Furthermore, tup5-1 also has a unique blue light-dependent short root phenotype: The root meristem is lost under blue light irradiation, resulting in root growth stop in the mutant (Frémont, 2004). In the following work, it was shown that the inhibiting light is perceived by the root. The cells constituting this short, growth arrested root have a strongly reduced metabolic activity, but are still viable. The gene encoding TUP5 was identified as an acetylornithine aminotransferase (ACOAT), catalysing the fourth step of arginine biosynthesis. The tup5-1 mutation is located in the third exon of At1g80600 causing an amino acid substitution (G424R). The amino acid targeted by this substitution is conserved in the homologous genes of bacteria, fungi and plants. Consistently, the free arginine content was reduced in tup5-1 compared to the wild type and root growth was restored in the mutant by exogenous supplementation of arginine. As an additional functional proof, a yeast mutant lacking ACOAT which was auxotrophic for arginine could restore its arginine autotrophy after transformation with the Arabidopsis TUP5 cDNA. Microarray data and real-time PCR showed that TUP5 is expressed in rosette leaves, stems, flowers, siliques and roots. Furthermore, TUP5 expression is positively regulated by light. A TUP5-GFP fusion showed that TUP5 is most likely localised in chloroplasts. A knockout of TUP5 is lethal, as was shown for T-DNA insertion alleles. This confirms the crucial role of TUP5 as a single copy gene. The loss of root meristem in tup5-1 might be directly caused by the lack of arginine or by accumulation of other metabolites in toxic amounts, as the amino acid metabolism is more generally deregulated in tup5-1. The mechanisms linking the short root phenotype to arginine deficiency and blue light signalling still have to be elucidated. The mutant tup5-1 provides a link between primary metabolism, plant development and blue light signalling.Arginin ist eine von 20 proteinogenen Aminosäuren, die für die Bildung von Peptiden und Proteinen benötigt werden. Zusätzlich wird Arginin zur Stickstoffspeicherung in Samen eingelagert und ist außerdem eine Vorstufe von Polyaminen und Stickoxid, die eine wichtige Rolle in Entwicklungsprozessen und bei der Streßantwort auf Umwelteinflüsse spielen. Die Synthesewege von Aminosäuren in Pflanzen wurden lange Zeit vorwiegend von bekannten Stoffwechselwegen aus Bakterien und Pilzen abgeleitet. In der vorliegenden Arbeit wird die erste umfassende Charakterisierung einer Argininbiosynthese- Mutante in Arabidopsis beschrieben. Die EMS-Mutante tup5-1 (tumor prone 5-1) wurde in einem genetischen Hormonsensitivitätsscreen gefunden. Wurzel- und Hypokotylexplantate dieser Mutante bildeten in vitro vermehrt Kalli auf Medium mit geringen Auxin- und Cytokininkonzentrationen (Riefler, 2001). tup5-1 zeigte außerdem eine bisher nicht beschriebene blaulichtabhängige Ausdifferenzierung des Wurzelmeristems, die zum Stop des Wurzelwachstums führte (Frémont, 2004). In der vorliegenden Arbeit wurde die Mutante weiter charakterisiert und die Funktion des betroffenen Gens untersucht. Es konnte gezeigt werden, daß das inhibierende Licht in der Wurzel perzipiert wird, und daß die Wurzelzellen des ausdifferenzierten Wurzelmeristems in ihrer Stoffwechselaktivität stark eingeschränkt sind. Das Gen, das für TUP5 kodiert, wurde als Acetylornithin-Aminotransferase (ACOAT) identifiziert. Das Enzym katalysiert den vierten Schritt der Arginin-Biosynthese. Die tup5-1 Mutation ist im dritten Exon von At1g80600 lokalisiert und bewirkt eine Aminosäuresubstitution (G424R). Die von dieser Substitution betroffene Aminosäure ist in homologen ACOATs von Bakterien, Pilzen und Pflanzen konserviert. Die aufgrund von Sequenzvergleichen postulierte Funktion von TUP5 in der Argininbiosynthese konnte auf verschiedene Weise bestätigt werden: Zum einen war der Arginingehalt in tup5-1 im Vergleich zu Wildtyp wegen der Störung in der Argininbiosynthese stark reduziert, zum anderen konnte das Wurzelwachstum in der Mutante durch exogene Gabe von Arginin wiederhergestellt werden. Als zusätzlicher funktioneller Nachweis konnte eine Hefe-Mutante, die aufgrund des fehlenden homologen ACOAT-Gens argininauxotroph war, durch Transformation mit der Arabidopsis TUP5 cDNA komplementiert werden. Microarray-Daten und qRT-PCR-Experimente zeigten, daß TUP5 in Rosettenblättern, Sproß, Blüten, Schoten und Wurzeln exprimiert und durch Licht positiv reguliert wird. Durch Untersuchung eines TUP5-GFP- Fusionsproteins in transformierten Protoplasten konnte gezeigt werden, daß TUP5 mit größter Wahrscheinlichkeit in Chloroplasten lokalisiert ist. Die Untersuchung von T-DNA-Insertionslinien ergab, daß sich ein kompletter Verlust der TUP5 Funktion letal auswirkt. Dies bestätigt die überlebenswichtige Rolle von TUP5, von dem nur eine einzige Kopie im Arabidopsis-Genom vorliegt. Zusammenfassend kann gesagt werden, daß die Mutante tup5-1 eine bisher unbekannte Verbindung zwischen Primärmetabolismus, Pflanzenentwicklung und Blaulicht-Perzeption in Arabidopsis aufzeigt

Proceedings of the 28th European Symposium on the reliability of electron devices, failure physics and analysis

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Proceedings of the 32nd European Symposium on the Reliability of Electron Devices, Failure Physics and Analysis

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Harcèlement moral au travail et justice organisationnelle : quels effets sur l'engagement au travail, l'intention de quitter et la détresse psychologique ?

La présente étude, dans la continuité de deux modèles (Desrumaux, 2011 ; Poilpot-Rocaboy, 2011) a pour but d’évaluer les effets du harcèlement moral au travail (HMT) et de la justice organisationnelle (JO) sur la santé psychologique.Un questionnaire a été rempli par des salariés (N = 424) de deux régions françaises, le Nord-Pas-Calais et les Pays de la Loire. Les analyses de régression montrent que le HMT explique une forte intention de quitter l’entreprise et une détresse psychologique élevée. Les justices distributive, procédurale, interpersonnelle et informationnelle ont un impact significatif sur l’engagement dans l’organisation et expliquent l’émergence du HMT

Effects of Heat Treatment and Pectin Addition on β -Lactoglobulin Allergenicity

International audienceThe specific effects of heat treatment and/or addition of low/high-methylated pectin (LMP/HMP) on the allergenicity of β-lactoglobulin (β-Lg) and its hydrolysis products were investigated through a two-step in vitro digestion approach. β-Lg was first hydrolyzed by pepsin and then by a trypsin/chymotrypsin (T/C) mixture done in a dialysis bag with a molecular weight cutoff of 1000. The protein digestion was followed by SDS-PAGE electrophoresis performed on each digestion product, and their in vitro allergenicity was analyzed by immunoblotting. Such procedure was applied on β-Lg samples mixed with the two kinds of pectin before or after heating (80 °C, 25 min) to determine the respective impact of heat treatment and pectin addition. Heat denaturation improved significantly the susceptibility of β-Lg against the pepsin and the T/C. This effect, which was coupled to a reduction in immunoreactivity of the digested β-Lg, appeared to be distinctively modulated by LMP and HMP. Through nonspecific interaction with the β-Lg, pectin could reduce the accessibility of cleavage sites and/or epitope sequences. This mechanism of action is discussed in relation to the intra- and intermolecular interactions between β-Lg and pectin initiated under the experimental conditions

Proceedings of the 30th European Symposium on the reliability of electron devices, failure physics and analysis

International audienceThis special issue of Microelectronics and Reliability is devoted to the publication of the papers presented during the 30th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, ESREF 2019, in Toulouse (France) from September 23th to September 26th, 2019.This international symposium continues to focus on recent developments and future directions in quality and reliability management of materials, devices and circuits for micro-, nano-, and optoelectronics. It provides a European forum for developing all aspects of reliability management and innovative analysis techniques for present and future electronic applications.For this 30th edition, in addition to the core topics of the conference, we involved the major actors of aeronautics, space and embedded systems industry to provide specific topics such as radiation hardening, very long-term reliability, high/low temperature challenges, obsolescence and counterfeit issues, wide bandgap power devices for the more electric aircraft and other embedded system applications. A special session for space and aeronautic systems is proposed

The viral restriction factor tetherin/BST2 tethers cytokinetic midbody remnants to the cell surface

International audienceThe midbody at the center of the intercellular bridge connecting dividing cells recruits the machinery essential for the final steps of cytokinesis.1-5 Successive abscission on both sides of the midbody generates a free midbody remnant (MBR) that can be inherited and accumulated in many cancer, immortalized, and stem cells, both in culture and in vivo.6-12 Strikingly, this organelle was recently shown to contain information that induces cancer cell proliferation, influences cell polarity, and promotes dorso-ventral axis specification upon interaction with recipient cells.13-16 Yet the mechanisms by which the MBR is captured by either a daughter cell or a distant cell are poorly described.10,14 Here, we report that BST2/tetherin, a well-established restriction factor that blocks the release of numerous enveloped viruses from the surface of infected cells,17-20 plays an analogous role in retaining midbody remnants. We found that BST2 is enriched at the midbody during cytokinesis and localizes at the surface of MBRs in a variety of cells. Knocking out BST2 induces the detachment of MBRs from the cell surface, their accumulation in the extracellular medium, and their transfer to distant cells. Mechanistically, the localization of BST2 at the MBR membrane is both necessary and sufficient for the interaction between MBRs and the cell surface. We thus propose that BST2 tethers post-cytokinetic midbody remnants to the cell surface. This finding reveals new parallels between cytokinesis and viral biology21-26 that unexpectedly extend beyond the ESCRT-dependent abscission step