Argos, du palais à l'agora

It is possible to read in vestiges of Argos the stages of its political and urbanistic history from the Mycenaean palace to the classical Agora. The examination of the different archaeological evidence helps us to understand the transfer of the power places and their symbolic value. We gain new insights into the formation of the city by observing the topograaphical relationship between the Armour Tomb and the "theatron" and its position between the high and the low.Du palais mycénien à l'agora classique, il est possible de lire dans les vestiges de la ville d'Argos les étapes de son histoire politique et urbaine. Les différents témoignages archéologiques sont mis en perspective et permettent de comprendre le déplacement des lieux de pouvoir ainsi que leur valeur symbolique. La tombe de l'armure mise en relation avec le "theatron" et replacée dans son contexte topographique, entre le haut et le bas, donne un nouvel éclairage sur la formation de la cité.Viret-Bernal Francine. Argos, du palais à l'agora. In: Dialogues d'histoire ancienne, vol. 18, n°1, 1992. pp. 61-88

The effectiveness of stilbenes in resistant Vitaceae: ultrastructural and biochemical events during Plasmopara viticola infection process

Leaves of different Vitis vinifera L. cultivars, susceptible or resistant to downy mildew, Chasselas, Solaris, IRAC 2091 (cvs. Gamaret x Bronner) and Muscadinia rotundifolia were inoculated with Plasmopara viticola. Samples were then examined by scanning and transmission electron microscopy, by light microscopy and for their ability to synthesise stilbenes. These phytoalexins were strictly analysed at infection sites. In the susceptible Chasselas, P. viticola colonises, at 72 h post-infection (hpi), all of the spongy mesophyll with functional haustoria and produces mainly the non toxic piceide. No necrotic zone was observed on Chasselas leaves. The ultrastructural response to downy mildew infection is different in each of the other three resistant grape cultivars. In Solaris, where leaf necrosis are rapidly induced, the infection is restricted to the upper part of the loose spongy mesophyll, and associated with a rapid cell wall disruption and the dispersion of cytoplasmic content along with the production of viniferins. In IRAC 2091, leaf necrosis are quite similar to those observed on Solaris but the infected plant cell, as well as the haustoria, show high electron dense cellular particles without any recognisable organelles, probably related to the effect of the toxic compound pterostilbene, which is synthesised in this grape cultivar. In M. rotundifolia leaf necrosis are much more scarce and smaller than in other cultivars, but pathogen and plant cells are both strongly affected, with concomitant expulsion of cytoplasmic materials through the stomata after P. viticola penetration. In this cultivar, the concentration of all identified stilbenes exceeds 1 × 103 μmol mg−1 FW. The critical role of stilbenes in the resistance of Vitis spp. is discussed.The authors thank Dr. Roger Pezet for critically reading the manuscript, Mr. Eric Remolif for production of grapevine cuttings and Ms. Sevan Kuyumcuyan for helpful technical assistance. We gratefully acknowledge the Juana de Vega Foundation (Spain) for its financial support.Fundación Juana de VegaPeer reviewe

Développement d’un programme de patients simulés : partage de quinze ans d’expérience à l’Université de Lausanne

Contexte : Il y a plus de 15 ans, l’École de médecine de la Faculté de biologie et de médecine de l’Université de Lausanne (Suisse) s’est dotée d’un programme de patients simulés. Celui-ci a pour mission de contribuer à la formation et à l’évaluation des étudiants en médecine et à la formation continue des professionnels de la santé de plusieurs institutions. Objectifs : Cette publication décrit les ressources qui ont été nécessaires au développement du programme, les rôles pédagogiques des patients simulés et les processus de recrutement, formation et encadrement mis en place. Conclusion : Les standards de bonnes pratiques ont guidé l’évolution du programme, pour en faire un acteur reconnu de la formation dans le domaine de la santé

Physiological and histological approaches to study berry shrivel in grapes

Aims: The current work aims to study berry shrivel in grapes (a grape-ripening disorder) in relation to vine water status and climatic conditions using physiological and histological approaches. Methods and results: Measurements of rachis hydraulic conductance on grapevine clusters (Vitis vinifera L.) and observations of the vascular tissues (xylem and phloem) using transmission electron microscopy were conducted on rachises from healthy clusters and clusters having berry shrivel (BS) symptoms during the season. BS intensity was largely dependent on the vine water status: BS was greater in vines without water stress than in vines with moderate to high water stress around veraison time. Preliminary results showed that rachis hydraulic conductance declined sharply after veraison but remained slightly higher in healthy clusters in comparison with clusters presenting BS symptoms. An important degradation of the primary phloem was observed in the rachises of BS clusters, with the appearance of hard, non-functional liber (secondary phloem) and a disorganization of the cell content in the phloem tissue. An alteration of the primary xylem was also observed in the middle of the rachis and in the secondary rachis ramifications. Conclusion: These results suggest that the decrease in sugar and water accumulation in BS berries would primarily be associated with a decline in rachis phloem functionality. Significance and impact of the study: The management of the vine water status plays a key role in berry shrivel development

T cell activation by antigens on human melanoma cells--co-stimulation by B7-1 is neither sufficient nor necessary to stimulate IL-2 secretion by melanoma-specific T cell clones in vitro

International audienceB7-1 expression, Induced by transfectlon in poorly Immunogenic murine tumours, was shown to elicit a T cell-mediated rejection of these tumours and further active immunity against the nontransfected tumour. We therefore asked to what level similarly induced expression of B7 on human melanoma cells would affect the antigen-dependent responses of tumour-speclflc T cell clones In vitro. Data presented show that B7-1 expression by melanoma lines: (I) significantly Induced, or improved, an IL-2-dependent prollferatlve response of such clones to the antigen; (II) Increased the amount of IL-2 produced by two clones In response to the parental non-transfected tumour cells; and (ill) increased the TNF responses of all the CD4 + clones. However, despite these clear co-stimulatory effects on antigen-Induced responses of all T cell clones, which demonstrated an effective interaction of the B7-1 transfected molecule with one or the other of Its counter-receptors expressed on T cell clones, B7 co-stimulation did not correct the defect of IL-2 secretion exhibited by many of these clones in response to In vitro antigen presentation by melanoma cells. We further show that defective IL-2 secretion in response to melanoma antigens was not due to a T cell clone refractoriness induced by the culture, since one of these clones could be Induced to secrete IL-2 by an antigen-expressing melanoma line, upon increased lymphocyte function associated antlgen-3 expression Induced by gene transfectlon. Together these data suggest that defective IL-2 secretion by many tumour-infiltrating lymphocytes clones in response to antigen presentation by melanoma cells In vitro is not exclusively due to the inability of these cells to provide an appropriate co-stimulation through the B7-1 molecule

Protease inhibitors decrease the resistance of Vitaceae to Plasmopara viticola

Plasmopara viticola must successfully infect susceptible grapevine cultivars to complete its biological cycle. In resistant grapevine varieties, P. viticola is blocked by the activation of defense mechanisms; these defense mechanisms produce hypersensitive reactions, which are related to programmed cell death. In animals, programmed cell death is dependent on caspase activities. In plants, different caspase-like proteases assume the same functions. To examine the roles of caspase-like proteases in P. viticola-grapevine interactions, three varieties of grapevine with different levels of P. viticola resistance were chosen. These grapevine varieties were treated with either PMSF, a serine protease inhibitor, or E-64, a cysteine protease inhibitor. The development of the pathogen was followed microscopically, and the plant defense reactions were estimated through stilbene quantification. Both protease inhibitor treatments increased the infection rate in the resistant and immune varieties, diminished the production of toxic stilbenes and changed the level of the plants' susceptibility to the pathogen. In particular, after either protease treatment, the cultivar that was originally immune became resistant (hyphae and haustoria were observed), the resistant cultivar reached the level of a susceptible cultivar (sporulation was observed) and the susceptible cultivar became more sensitive (P. viticola colonized the entirety of the leaf mesophyll). © 2012 Elsevier Masson SAS.We gratefully acknowledge the Juana de Vega Foundation (Spain) for its financial support.Peer Reviewe

Susceptibility to downy mildew in grape clusters: New microscopical and biochemical insights

Grape clusters of different Vitis genotypes, including Vitis vinifera cvs Chasselas and Merlot, and two interspecific grape varieties, Solaris (cvs. Merzling* x (Saperavi severneyi x Muscat ottonel)) and 2091 (cvs. Gamaret x Bronner), are susceptible or resistant to downy mildew. These cultivars were inoculated with Plasmopara viticola at three developmental stages (BBCH stages 53, 69 and 75). Samples were examined by scanning electron microscopy and the synthesis of stilbenes was measured. Microscopical examinations of pedicels, rachis and calyptras showed important differences in stomatal structures within seasonal development. At BBCH 53, successful infections were observed on all tested cultivars and functional stomata were present, while no infections were observed after this stage. At BBCH 69 and 75, cracks were observed around the stomata and guard cells were unstructured or completely collapsed, leading to closed-like stomata. At BBCH 53, significant stilbene accumulation was quantified in 2091 and Solaris; pterostilbene and ο-viniferin were produced in large amounts. In the susceptible varieties, only piceid and resveratrol were induced. At the other two stages, the concentration of all measured stilbenes was undetectable. The critical roles of seasonal development and stilbenes in the resistance of grape clusters towards downy mildew are discussed. © 2011 Elsevier Masson SAS.We gratefully acknowledge the Juana de Vega Foundation (Spain) for its financial support.Peer Reviewe