Quelle serait une bonne définition du musée au XXIe siècle ?

Cet article est extrait du dossier « Vers une nouvelle définition du musée ? » dirigé par Ewa Maczek, directrice par intérim de l'Ocim. La définition du musée proposée depuis 2007 par l'Icom fait référence dans la sphère muséale mondiale. Si la volonté de faire évoluer cette définition fait sens, la proposition du Comité pour la Définition du musée, perspectives et potentiels (MDPP) de l'Icom a surpris bon nombre de professionnels et d'institutions, et tout particulièrement en France. La lettre de l'Ocim leur a ouvert ses pages pour qu’ils partagent leurs réactions

A note on topological properties of volumes constructed from surfaces

Converting surfaces into a volume has a long interest in several communities, e.g. the computational mechanics community. This process involves having specific surfaces which can be converted into a solid, i.e., a volume. This paper presents in a clear and brief manner the topological properties conserved during surface to volume transformation. We state the limits of this approach if a specific volume structure is required. Volume structures can be a coarse volume organization or meshes. For that purpose, surface manifolds are mathematically turned into a volume manifold. Topological tools are presented to understand which properties are transmitted to the volume and which ones are unset. Developments are submitted both for continuous and discrete manifolds using CW-complexes

Le Palais de la découverte 2024 : réflexions sur un projet

Le Palais de la découverte, lieu emblématique et historique de la culture scientifique et technique fera bientôt l’objet d’une rénovation attendue. Bruno Maquart, président d’Universcience, revient sur le contexte, les étapes et les axes forts du projet

Expression of Glycosaminoglycans and Small Proteoglycans in Wounds: Modulation by the Tripeptide–Copper Complex Glycyl-L-Histidyl-L-Lysine-Cu2+

Glycyl-histidyl-lysine-Cu2+ is a tripeptide–copper complex previously shown to be an activator of wound healing. We have investigated the effects of glycyl-histidyl-lysine-Cu2+ on the synthesis of glycosaminoglycans and small proteoglycans in a model of rat experimental wounds and in rat dermal fibroblast cultures. Repeated injections of glycyl-histidyl-lysine-Cu2+ (2 mg per injection) stimulated the wound tissue production, as appreciated by dry weight and total protein measurements. This stimulation was accompanied by an increased production of type I collagen and glycosaminoglycans (assessed, respectively, by hydroxyproline and uronic acid contents of the chamber). Electrophoretic analysis of wound tissue glycosaminoglycans showed an accumulation of chondroitin sulfate and dermatan sulfate in control wound chambers, whereas the proportion of hyaluronic acid decreased with time. The accumulation of chondroitin sulfate and dermatan sulfate was enhanced by glycyl-histidyl-lysine-Cu2+ treatment. The expression of two small proteoglycans of the dermis, decorin and biglycan, was analyzed by northern blot. The biglycan mRNA steady-state level in the chamber was maximal at day 12, whereas the decorin mRNA increased progressively until the end of the experiment (day 22). Glycyl-histidyl-lysine-Cu2+ treatment increased the mRNA level of decorin and decreased those of biglycan. In dermal fibroblast cultures, the stimulation of decorin expression by glycyl-histidyl-lysine-Cu2+ was also found. In contrast, biglycan expression was not modified. These results show that the expression of different proteoglycans in wound tissue are regulated in a different manner during wound healing. The glycyl-histidyl-lysine-Cu2+ complex is able to modulate the expression of the extracellular matrix macromolecules differently during the wound repair process

Human collagen Krox up-regulates type I collagen expression in normal and scleroderma fibroblasts through interaction with Sp1 and Sp3 transcription factors.

Despite several investigations, the transcriptional mechanisms that regulate the expression of both type I collagen genes (COL1A1 and COL1A2) in either physiological or pathological situations, such as scleroderma, are not completely known. We have investigated the role of hc-Krox transcription factor on type I collagen expression by human dermal fibroblasts. hc-Krox exerted a stimulating effect on type I collagen protein synthesis and enhanced the corresponding mRNA steady-state levels of COL1A1 and COL1A2 in foreskin fibroblasts (FF), adult normal fibroblasts (ANF), and scleroderma fibroblasts (SF). Forced hc-Krox expression was found to up-regulate COL1A1 transcription through a -112/-61-bp sequence in FF, ANF, and SF. Knockdown of hc-Krox by short interfering RNA and decoy strategies confirmed the transactivating effect of hc-Krox and decreased substantially COL1A1 transcription levels in all fibro-blast types. The -112/-61-bp sequence bound specifically hc-Krox but also Sp1 and CBF. Attempts to elucidate the potential interactions between hc-Krox, Sp1, and Sp3 revealed that all of them co-immunoprecipitate from FF cellular extracts when a c-Krox antibody was used and bind to the COL1A1 promoter in chromatin immunoprecipitation assays. Moreover, hc-Krox DNA binding activity to its COL1A1-responsive element is increased in SF, cells producing higher amounts of type I collagen compared with ANF and FF. These data suggest that the regulation of COL1A1 gene transcription in human dermal fibroblasts involves a complex machinery that implicates at least three transcription proteins, hc-Krox, Sp1, and Sp3, which could act in concert to up-regulate COL1A1 transcriptional activity and provide evidence for a pro-fibrotic role of hc-Krox

MLVA-16 typing of 295 marine mammal Brucella isolates from different animal and geographic origins identifies 7 major groups within Brucella ceti and Brucella pinnipedialis

<p>Abstract</p> <p>Background</p> <p>Since 1994, <it>Brucella </it>strains have been isolated from a wide range of marine mammals. They are currently recognized as two new <it>Brucella </it>species, <it>B. pinnipedialis </it>for the pinniped isolates and <it>B. ceti </it>for the cetacean isolates in agreement with host preference and specific phenotypic and molecular markers. In order to investigate the genetic relationships within the marine mammal <it>Brucella </it>isolates and with reference to terrestrial mammal <it>Brucella </it>isolates, we applied in this study the Multiple Loci VNTR (Variable Number of Tandem Repeats) Analysis (MLVA) approach. A previously published assay comprising 16 loci (MLVA-16) that has been shown to be highly relevant and efficient for typing and clustering <it>Brucella </it>strains from animal and human origin was used.</p> <p>Results</p> <p>294 marine mammal <it>Brucella </it>strains collected in European waters from 173 animals and a human isolate from New Zealand presumably from marine origin were investigated by MLVA-16. Marine mammal <it>Brucella </it>isolates were shown to be different from the recognized terrestrial mammal <it>Brucella </it>species and biovars and corresponded to 3 major related groups, one specific of the <it>B. ceti </it>strains, one of the <it>B. pinnipedialis </it>strains and the last composed of the human isolate. In the <it>B. ceti </it>group, 3 subclusters were identified, distinguishing a cluster of dolphin, minke whale and porpoise isolates and two clusters mostly composed of dolphin isolates. These results were in accordance with published analyses using other phenotypic or molecular approaches, or different panels of VNTR loci. The <it>B. pinnipedialis </it>group could be similarly subdivided in 3 subclusters, one composed exclusively of isolates from hooded seals (<it>Cystophora cristata</it>) and the two others comprising other seal species isolates.</p> <p>Conclusion</p> <p>The clustering analysis of a large collection of marine mammal <it>Brucella </it>isolates from European waters significantly strengthens the current view of the population structure of these two species, and their relative position with respect to the rest of the <it>Brucella </it>genus. MLVA-16 is confirmed as being a rapid, highly discriminatory and reproducible method to classify <it>Brucella </it>strains including the marine mammal isolates. The <it>Brucella2009 </it>MLVA-16 genotyping database available at <url>http://mlva.u-psud.fr/</url> is providing a detailed coverage of all 9 currently recognized <it>Brucella </it>species.</p