Objets de peu

RésuméÀ partir d’une approche ethnographique, ce texte analyse la manière dont le marché à réderies, ou vide-grenier, propose un mode communautaire de recyclage des objets de peu. À l’extrême de leur fonctionnalité, de leur valeur d’usage, s’entrevoit en eux la possibilité du rachat de l’histoire comme conservation de ce qui ne doit pas disparaître. Ce rachat repose sur l’accomplissement d’un travail de mémoire par lequel l’histoire se voit triée, jugée et construite. La dette envers l’histoire, par l’intermédiaire de l’objet, peut s’entendre comme devoir de mémoire.AbstractThis text analyzes, from an ethnographic standpoint, the way in which «réderies» markets – local jumble sales – offer a collective means of recycling objects of little value. Having almost exhausted their practicality and become useless, they offer the possibility of historical redemption through the preservation of what must be safeguarded. Acquiring these objects implies a process of remembrance whereby history is sorted out, judged and written. Our debt towards history, embodied by these objects, can be construed as a necessary act of remembrance

Nanoscale glucan polymer network causes pathogen resistance.

Successful defence of plants against colonisation by fungal pathogens depends on the ability to prevent initial penetration of the plant cell wall. Here we report that the pathogen-induced (1,3)-β-glucan cell wall polymer callose, which is deposited at sites of attempted penetration, directly interacts with the most prominent cell wall polymer, the (1,4)-β-glucan cellulose, to form a three-dimensional network at sites of attempted fungal penetration. Localisation microscopy, a super-resolution microscopy technique based on the precise localisation of single fluorescent molecules, facilitated discrimination between single polymer fibrils in this network. Overexpression of the pathogen-induced callose synthase PMR4 in the model plant Arabidopsis thaliana not only enlarged focal callose deposition and polymer network formation but also resulted in the exposition of a callose layer on the surface of the pre-existing cellulosic cell wall facing the invading pathogen. The importance of this previously unknown polymeric defence network is to prevent cell wall hydrolysis and penetration by the fungus. We anticipate our study to promote nanoscale analysis of plant-microbe interactions with a special focus on polymer rearrangements in and at the cell wall. Moreover, the general applicability of localisation microscopy in visualising polymers beyond plant research will help elucidate their biological function in complex networks

Callose-mediated resistance to pathogenic intruders in plant defense-related papillae

Plants are exposed to a wide range of potential pathogens, which derive from diverse phyla. Therefore, plants have developed successful defense mechanisms during co-evolution with different pathogens. Besides many specialized defense mechanisms, the plant cell wall represents a first line of defense. It is actively reinforced through the deposition of cell wall appositions, so-called papillae, at sites of interaction with intruding microbial pathogens. The papilla is a complex structure that is formed between the plasma membrane and the inside of the plant cell wall. Even though the specific biochemical composition of papillae can vary between different plant species, some classes of compounds are commonly found which include phenolics, reactive oxygen species, cell wall proteins, and cell wall polymers. Among these polymers, the (1,3)-β-glucan callose is one of the most abundant and ubiquitous components. Whereas the function of most compounds could be directly linked with cell wall reinforcement or an anti-microbial effect, the role of callose has remained unclear. An evaluation of recent studies revealed that the timing of the different papilla-forming transport processes is a key factor for successful plant defense

Le culte de saint Yves à Paris

Saint Yves, décédé en 1303, reçut les honneurs de la canonisation en 1347. Dès l’année suivante, les Bretons qui se trouvaient à Paris conçurent l’idée d’y former une confrérie et d’y bâtir une église en son honneur. Ils entretinrent de leur projet Foulques évêque de Paris, et le prélat approuva cette fondation par des lettres datées du mois d’août 1348. L’emplacement de l’édifice fut choisi dans le quartier des Écoles où le souvenir du Bienheureux était encore vivant, il ouvrait sur la rue S..

Martor. Revue d'Anthropologie du Musée du Paysan Roumain, 1996, I : L'étranger autochtone

Debary Octave. Martor. Revue d'Anthropologie du Musée du Paysan Roumain, 1996, I : L'étranger autochtone. In: L'Homme, 1998, tome 38 n°145. De l'esclavage. pp. 282-284