Évolution de la végétation du marais de Lavours (Ain, France) à quarante-cinq ans d'intervalle (1967-2012)

Evolution of the Lavours marsh vegetation with a forty-five years interval (1967-2012). - Vegetation maps of the Lavours marsh realized 45 years apart are compared. The main changes in vegetal landscape and land use include : (i) transformation into crop fields of large surfaces of wet meadows, (ii) the spontaneous or chosen development of forest and (iii) the development of an open eutrophic vegetation, due to the water table lowering and the subsequent nutrient enrichment of habitats on silt substrate. In this context, the Réserve naturelle nationale du Marais de Lavours plays a major role for open habitats conservation on peat soils, which have almost disappeared in the rest of the marsh. The situation of open habitats on silt substrate is more moderate because half of them are outside of the nature reserve, dispached in small unmanaged islands.Les cartes de végétation du marais de Lavours établies à 45 ans d'intervalle sont comparées. L'évolution du paysage végétal et de l'utilisation du sol comprend : (i) la mise en culture de grandes surfaces de prairies hygrophiles, (ii) le retour spontané ou choisi de la forêt et (iii) le développement d'une végétation ouverte eutrophe, dû à l'abaissement de la nappe phréatique et à l'eutrophisation des habitats sur limons. Dans ce contexte, la Réserve naturelle nationale du Marais de Lavours joue un rôle majeur pour la préservation des milieux ouverts sur tourbe qui ont disparu du reste du marais. La situation des milieux ouverts sur limons est plus mitigée car la moitié des surfaces restantes est située en dehors de la réserve, en îlots relictuels non gérés.Mikolajczak Alexis, Darinot Fabrice. Évolution de la végétation du marais de Lavours (Ain, France) à quarante-cinq ans d'intervalle (1967-2012). In: Bulletin mensuel de la Société linnéenne de Lyon, hors-série numéro 3, 2014. Bilan de 30 ans d'études scientifiques dans le marais de Lavours (1984-2014) pp. 42-53

Suppression of Host p53 Is Critical for Plasmodium Liver-Stage Infection

Plasmodium parasites infect the liver and replicate inside hepatocytes before they invade erythrocytes and trigger clinical malaria. Analysis of host signaling pathways affected by liver-stage infection could provide critical insights into host–pathogen interactions and reveal targets for intervention. Using protein lysate microarrays, we found that Plasmodium yoelii rodent malaria parasites perturb hepatocyte regulatory pathways involved in cell survival, proliferation, and autophagy. Notably, the prodeath protein p53 was substantially decreased in infected hepatocytes, suggesting that it could be targeted by the parasite to foster survival. Indeed, mice that express increased levels of p53 showed reduced liver-stage parasite burden, whereas p53 knockout mice suffered increased liver-stage burden. Furthermore, boosting p53 levels with the use of the small molecule Nutlin-3 dramatically reduced liver-stage burden in vitro and in vivo. We conclude that perturbation of the hepatocyte p53 pathway critically impacts parasite survival. Thus, host pathways might constitute potential targets for host-based antimalarial prophylaxis

Vegetation ecology meets ecosystem science: Permanent grasslands as a functional biogeography case study

International audienceThe effect of biodiversity on ecosystem functioning has been widely acknowledged, and the importance of the functional roles of species, as well as their diversity, in the control of ecosystem processes has been emphasised recently. However, bridging biodiversity and ecosystem science to address issues at a biogeographic scale is still in its infancy. Bridging this gap is the primary goal of the emerging field of functional biogeography. While the rise of Big Data has catalysed functional biogeography studies in recent years, comprehensive evidence remains scarce. Here, we present the rationale and the first results of a country-wide initiative focused on the C-3 permanent grasslands. We aimed to collate, integrate and process large databases of vegetation releves, plant traits and environmental layers to provide a country-wide assessment of ecosystem properties and services which can be used to improve regional models of climate and land use changes. We outline the theoretical background, data availability, and ecoinformatics challenges associated with the approach and its feasibility. We provide a case study of upscaling of leaf drymatter content averaged at ecosystemlevel and country-wide predictions of forage digestibility. Our framework sets milestones for further hypothesis testing in functional biogeography and earth system modelling. (C) 2015 Elsevier B.V. All rights reserved