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Search Results: 1 - 10 of 9204 matches for " Marie-Laure Parmentier "
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A Huntingtin Peptide Inhibits PolyQ-Huntingtin Associated Defects
Yoan Arribat, Nathalie Bonneaud, Yasmina Talmat-Amar, Sophie Layalle, Marie-Laure Parmentier, Florence Maschat
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068775
Abstract: Background Huntington’s disease (HD) is caused by the abnormal expansion of the polyglutamine tract in the human Huntingtin protein (polyQ-hHtt). Although this mutation behaves dominantly, huntingtin loss of function also contributes to HD pathogenesis. Indeed, wild-type Huntingtin plays a protective role with respect to polyQ-hHtt induced defects. Methodology/Principal Findings The question that we addressed here is what part of the wild-type Huntingtin is responsible for these protective properties. We first screened peptides from the Huntingtin protein in HeLa cells and identified a 23 aa peptide (P42) that inhibits polyQ-hHtt aggregation. P42 is part of the endogenous Huntingtin protein and lies within a region rich in proteolytic sites that plays a critical role in the pathogenesis process. Using a Drosophila model of HD, we tested the protective properties of this peptide on aggregation, as well as on different polyQ-hHtt induced neuronal phenotypes: eye degeneration (an indicator of cell death), impairment of vesicular axonal trafficking, and physiological behaviors such as larval locomotion and adult survival. Together, our results demonstrate high protective properties for P42 in vivo, in whole animals. These data also demonstrate a specific role of P42 on Huntington’s disease model, since it has no effect on other models of polyQ-induced diseases, such as spinocerebellar ataxias. Conclusions/Significance Altogether our data show that P42, a 23 aa-long hHtt peptide, plays a protective role with respect to polyQ-hHtt aggregation as well as cellular and behavioral dysfunctions induced by polyQ-hHtt in vivo. Our study also confirms the correlation between polyQ-hHtt aggregation and neuronal defects. Finally, these results strongly suggest a therapeutic potential for P42, specific of Huntington’s disease.
Plant Insecticide L-Canavanine Repels Drosophila via the Insect Orphan GPCR DmX
Christian Mitri,Laurent Soustelle,Bérénice Framery,Jo?l Bockaert,Marie-Laure Parmentier,Yves Grau
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.1000147
Abstract: For all animals, the taste sense is crucial to detect and avoid ingesting toxic molecules. Many toxins are synthesized by plants as a defense mechanism against insect predation. One example of such a natural toxic molecule is l-canavanine, a nonprotein amino acid found in the seeds of many legumes. Whether and how insects are informed that some plants contain l-canavanine remains to be elucidated. In insects, the taste sense relies on gustatory receptors forming the gustatory receptor (Gr) family. Gr proteins display highly divergent sequences, suggesting that they could cover the entire range of tastants. However, one cannot exclude the possibility of evolutionarily independent taste receptors. Here, we show that l-canavanine is not only toxic, but is also a repellent for Drosophila. Using a pharmacogenetic approach, we find that flies sense food containing this poison by the DmX receptor. DmXR is an insect orphan G-protein–coupled receptor that has partially diverged in its ligand binding pocket from the metabotropic glutamate receptor family. Blockade of DmXR function with an antagonist lowers the repulsive effect of l-canavanine. In addition, disruption of the DmXR encoding gene, called mangetout (mtt), suppresses the l-canavanine repellent effect. To avoid the ingestion of l-canavanine, DmXR expression is required in bitter-sensitive gustatory receptor neurons, where it triggers the premature retraction of the proboscis, thus leading to the end of food searching. These findings show that the DmX receptor, which does not belong to the Gr family, fulfills a gustatory function necessary to avoid eating a natural toxin.
Rapid functional diversification in the structurally conserved ELAV family of neuronal RNA binding proteins
Marie-Laure Samson
BMC Genomics , 2008, DOI: 10.1186/1471-2164-9-392
Abstract: We analyzed 23 orthologs/paralogs of elav, and found evidence of gain/loss of gene copy number. For one set of genes, including elav itself, the coding sequences are free of introns and their products most resemble ELAV. The remaining genes show remarkable conservation of their exon organization, and their products most resemble FNE and RBP9, proteins encoded by the two elav paralogs of Drosophila. Remarkably, three of the conserved exon junctions are both close to structural elements, involved respectively in protein-RNA interactions and in the regulation of sub-cellular localization, and in the vicinity of diverse sequence variations.The data indicate that the essential elav gene of Drosophila is newly emerged, restricted to dipterans and of retrotransposed origin. We propose that the conserved exon junctions constitute potential sites for sequence/function modifications, and that RRM binding proteins, whose function relies upon plastic RNA-protein interactions, may have played an important role in brain evolution.The elav (embryonic lethal abnormal visual system) gene of D. melanogaster was the the first identified member of a family of neuronal RNA binding proteins that is conserved in metazoans [1,2]. The proteins in this family contain three RNA Recognition Motifs (RRM), with a hinge region separating the second and third RRMs and an optional non-conserved N-terminal region. The hinge includes signals essential for nuclear export and subcellular localization [3].RRM are common protein domains found in all life kingdoms. In humans, there are 497 genes encoding RRM containing proteins, which represent 2% of the human gene products. Proteins containing one or several of these domains are capable of interacting in a sequence specific manner with single stranded RNA molecules and of directing the assembly of multiprotein complexes [4,5]. In spite of the remarkable sequence conservation of the RRM domains, RRM-containing proteins perform numerous functions, interven
"Thinking global, acting local": Antonym coordinations in a multidimensional construction grammar "Penser global, agir local" : Les coordinations antithétiques dans une grammaire de construction multi-dimensionnelle
Marie-Laure Guénot
Traitement Automatique des Langues , 2009,
Abstract: The aim of this paper is to present a description of antonym constructions, which is integrated in a formal grammar of spontanous french in order to allow its use for NLP. The characteristic of these constructions is to be simultaneously constrained at many different levels (lexicon, syntax, semantics and pragmatics). We rst present a description of the phenomenon, then we illustrate it by the example of an analysis, and nally we show its formalization and its integration in the grammar we develop.
La géographie légendaire d’un camp royal éthiopien du XVe siècle. Histoire d’une construction mémorielle The legendary geography of a 15th century Ethiopian “royal camp”: The history of the construction of a memory
Marie-Laure Derat
Afriques : Débats, Méthodes et Terrains d'Histoire , 2011, DOI: 10.4000/afriques.764
Abstract: Dire l’espace dans la région de Mes āla Māryām (Manz, éthiopie), c’est décrire, à partir de vestiges au sol et de points remarquables du paysage, un camp royal qui se serait implanté dans la région au milieu du xve siècle. Cette géographie légendaire est une concrétion de la mémoire à partir de différentes strates historiques. Le propos de cet article est de comprendre comment espace et mémoire se sont articulés pour fabriquer ce camp royal légendaire, en se fondant notamment sur l’analyse des généalogies recueillies sur place. Celles-ci témoignent de deux moments forts dans l’histoire du Manz : l’installation d’un roi chrétien dans la région, fondateur de l’église de Mes āla Māryām, au milieu du xve siècle, et la reconquête de la région à la fin du xviie siècle par un certain Gērā après le jihad mené par l’imam d’un sultanat voisin, suivi des migrations de populations qui s’en sont suivies et qui ont transformé le paysage religieux et politique de la région pendant un peu plus d’un siècle. Describing space in Mes āla Māryām (Manz, Ethiopia) entails relating remains on the ground and features of the landscape to an old royal camp, which was said to have been set up there in the mid-15th century. This legendary geography has settled out of several historical layers of memory. An analysis of genealogies collected in the field helps us understand how space and memory were brought together to create this legendary royal camp. These genealogies present two important periods in local history: first of all, the settlement of a Christian king in the area, who founded the Mes āla Māryām church in the mid-15th century, and secondly the reconquest of the area in the late 17th century by Gērā after a neighboring sultanate’s imam had waged a jihad with, as consequence, human migrations that reshaped the religious and political landscape for more than a century.
Introduction au dossier Les chemins de l’identité en Afrique du XVe au XXe siècle
Marie-Laure Derat
Afriques : Débats, Méthodes et Terrains d'Histoire , 2010, DOI: 10.4000/afriques.85
Abstract: Ce dossier est le fruit d’une rencontre entre chercheurs allemands du Seminar für Orientkunde de l’université de Mayence et de chercheurs fran ais du Centre d’études des mondes africains et de l’université Paris 1, réunis par un programme d’échange européen. Autour du thème Identités composées, dynamiques linguistiques et religieuses en Afrique , trois journées de discussions se sont tenues à Paris du 24 au 26 novembre 2003. Le propos de cette rencontre était d’exposer des études de ca...
Les tombeaux des rois Zāgwē, Yemre anna Krestos et Lālibalā (XIIe-XVIe siècle), et leurs évolutions symboliques Tombs of the Zāgwē kings, Yemre anna Krestos and Lālibalā (12th-16th century), and their evolving symbolic importance
Marie-Laure Derat
Afriques : Débats, Méthodes et Terrains d'Histoire , 2012, DOI: 10.4000/afriques.1030
Abstract: Les tombeaux de deux saints-rois de la dynastie éthiopienne des Zāgwē, Yemre anna Krestos et Lālibalā, sont réputés être situés dans les églises qu’ils auraient fondées. Mais cette information n’appara t pas dans les premiers textes consacrés aux rois-saints. Cet article tente de reprendre la chronologie des textes et de leur production, et d’identifier les moments où surgissent de nouveaux symboles destinés à authentifier les sépultures des saints-rois ou à modifier la perception de celles-ci en fonction des époques. Il s’agit de s’intéresser aux processus qui ont permis de situer ces tombes et de les considérer comme les tombes de saints, et non plus de rois. Les sépultures de Yemre anna Krestos et Lālibalā sont devenues le but de pèlerinages au cours desquels l’intercession de ces rois devenus saints est sollicitée. The tombs of two kings of the Zagwe dynasty, Yemrehanna Krestos and Lālibalā, are said to be located in churches that they founded. However this information does not figure in the first texts written about these Ethiopian saint-kings. The chronology of these texts and their production are presented; and the eras identified when new symbols emerged for authenticating the sepultures of saint-kings or modifying the perception of them. What processes led to identifying the location of these tombs and considering them to be the graves of saints, and no longer of kings? The tombs of these two kings have become places where pilgrims request these saints to intercede on their behalf.
La circoncision et l’excision en éthiopie du XVe au XVIIIe siècle : lectures d’un rituel
Marie-Laure Derat
Afriques : Débats, Méthodes et Terrains d'Histoire , 2010, DOI: 10.4000/afriques.415
Abstract: à partir de l’extrait du Ma āfa Berhān écrit sous la supervision du roi Zar’a Yā‘eqob (1434-1468) qui décrit la manière dont l’excision des jeunes filles doit être effectuée conformément à la loi de l’Ancien Testament, cet article analyse la manière dont l’excision et la circoncision étaient liées à l’église éthiopienne au xve siècle. Mais, au xviie siècle, les jésuites ont essayé de convertir le royaume éthiopien au catholicisme : ils ont considéré la circoncision comme une pratique juive et l’excision comme une coutume pa enne. Pour répondre à cette condamnation, les éthiopiens ont tenté de se justifier en gardant le lien entre la circoncision et l’excision et en les considérant comme des coutumes plut t que des rites chrétiens. Cet exemple montre comment un rite a pu être considéré de différentes manières selon les enjeux du moment. From an extract of the Ma āfa Berhān written under the supervision of King Zar’a Yā‘eqob (1434-1468) which describes how female circumcision of the girls should be done according to the law of the Old Testament, this article analyses how the excision and the circumcision were related in the Ethiopian Church in the Fifteenth Century. But in the Seventeenth Century, when the Jesuits tried to convert the Ethiopian Kingdom to catholicism, they looked at the circumcision as Jewish practice and the excision as a pagan custom. To answer to this condemnation, the Ethiopians tried to justify themselves by keeping the link between circumcision and excision and considering them as customs and not Christian rites. This example shows how a rite could be read in different ways according to the stakes of the present.
Le Chien de fa ence
Marie-Laure Schultze
Voix Plurielles , 2011,
Abstract: Marie-Laure Schultze est enseignante-chercheure depuis une vingtaine d'années. Elle a travaillé en Angleterre, au Canada et surtout en France, où elle est actuellement en poste à Aix-Marseille Université. Elle y a ouvert avec une collègue des ateliers (exceptionnellement rares dans les universités fran aises) de traduction créatrice et d’écriture plurilingue ; ces ateliers sont destinés à leurs étudiants apprenant l’anglais et consolidant le fran ais. En parallèle, et dans les interstices laissés par sa recherche sur la place de l’écriture créatrice dans l’apprentissage des langues et sa famille (un compagnon et trois enfants constituent le noyau de la drupe), elle écrit et publie bon an mal an cahin caha ses textes (de la fiction courte, du théatre, deux romans en chantier, des histoires pour enfants...) sur son blog http://carnetdetextes.wordpress.com/
La Lutte, Monoglose 29
Marie-Laure Schultze
Voix Plurielles , 2011,
Abstract: Marie-Laure Schultze est enseignante-chercheure depuis une vingtaine d'années. Elle a travaillé en Angleterre, au Canada et surtout en France, où elle est actuellement en poste à Aix-Marseille Université. Elle y a ouvert avec une collègue des ateliers (exceptionnellement rares dans les universités fran aises) de traduction créatrice et d’écriture plurilingue ; ces ateliers sont destinés à leurs étudiants apprenant l’anglais et consolidant le fran ais. En parallèle, et dans les interstices laissés par sa recherche sur la place de l’écriture créatrice dans l’apprentissage des langues et sa famille (un compagnon et trois enfants constituent le noyau de la drupe), elle écrit et publie bon an mal an cahin caha ses textes (de la fiction courte, du théatre, deux romans en chantier, des histoires pour enfants...) sur son blog http://carnetdetextes.wordpress.com/
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