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Venom atypical extracellular vesicles as interspecies vehicles of virulence factors involved in host specificity: the case of a Drosophila Parasitoid Wasp
No full textEndoparasitoid wasps, which lay eggs inside the bodies of other insects, use various strategies to protect their offspring from the host immune response. The hymenopteran species of the genus Leptopilina, parasites of Drosophila, rely on the injection of a venom which contains proteins and peculiar vesicles (hereafter venosomes). We show here that the injection of purified L. boulardi venosomes is sufficient to impair the function of the Drosophila melanogaster lamellocytes, a hemocyte type specialized in the defense against wasp eggs, and thus the parasitic success of the wasp. These venosomes seem to have a unique extracellular biogenesis in the wasp venom apparatus where they acquire specific secreted proteins/virulence factors and act as a transport system to deliver these compounds into host lamellocytes. The level of venosomes entry into lamellocytes of different Drosophila species was correlated with the rate of parasitism success of the wasp, suggesting that this venosome-cell interaction may represent a new evolutionary level of host-parasitoid specificity
A facile technique to extract the cross-sectional structure of brittle porous chars from Intumescent coatings
No full textIntumescent coatings are part of passive fire protection systems. In case of fire, they expand under thermal stimuli and reduce heat transfer rates. Their expansion mechanisms are more or less recognized, but the fire testing data shall be interpreted as function of coating morphology. Expansion ratios are examined together with the inner structures of specimens submitted to fire. Bare cutting techniques damage the highly porous and fibrous specimens because they become very crumbly due to charring. So far, absorption contrasted X-ray computed microtomography (CT) was used as a non-destructive technique. Nevertheless, access to X-ray platforms can be relatively expensive and scarce for regular use. Also, it has some drawbacks for carbon rich specimens strongly adhering on steel substrates because it leads sometimes to noisy images and lost data due to resolution limits on specimens reaching ten of centimeters. Therefore, we propose an inexpensive and more accessible experimental approach to observe those specimens with minimized structural damage under visible lighting. To that end, charred specimens were casted into pigmented epoxy resin. After surface treatments, color contrasted cross-sections could be observed under optical digital microscopy thanks to high level of interconnectivity of pores. Subsequent image treatments confirmed that the structural integrity was kept when compared to previous CT data. The proposed method is practical, cheaper and more accessible for the quantitative assessment of inner structure of charred brittle specimens
Mechanisms of adiponectin action in fertility: an overview from gametogenesis to gestation in humans and animal models in normal and pathological conditions
No full textAdiponectin is the most abundant plasma adipokine. It mainly derives from white adipose tissue and plays a key role in the control of energy metabolism thanks to its insulin-sensitising, anti-inflammatory, and antiatherogenic properties. In vitro and in vivo evidence shows that adiponectin could also be one of the hormones controlling the interaction between energy balance and fertility in several species, including humans. Indeed, its two receptors-AdipoR1 and AdipoR2-are expressed in hypothalamic⁻pituitary⁻gonadal axis and their activation regulates Kiss, GnRH and gonadotropin expression and/or secretion. In male gonads, adiponectin modulates several functions of both somatic and germ cells, such as steroidogenesis, proliferation, apoptosis, and oxidative stress. In females, it controls steroidogenesis of ovarian granulosa and theca cells, oocyte maturation, and embryo development. Adiponectin receptors were also found in placental and endometrial cells, suggesting that this adipokine might play a crucial role in embryo implantation, trophoblast invasion and foetal growth. The aim of this review is to characterise adiponectin expression and its mechanism of action in male and female reproductive tract. Further, since features of metabolic syndrome are associated with some reproductive diseases, such as polycystic ovary syndrome, gestational diabetes mellitus, preeclampsia, endometriosis, foetal growth restriction and ovarian and endometrial cancers, evidence regarding the emerging role of adiponectin in these disorders is also discussed
Salinity effects on sugar homeostasis and vascular anatomy in the stem of the Arabidopsis thaliana inflorescence
No full textThe regulation of sugar metabolism and partitioning plays an essential role for a plant’s acclimation to its environment, with specific responses in autotrophic and heterotrophic organs. In this work, we analyzed the effects of high salinity on sugar partitioning and vascular anatomy within the floral stem. Stem sucrose and fructose content increased, while starch reduced, in contrast to the response observed in rosette leaves of the same plants. In the stem, the effects were associated with changes in the expression of SWEET and TMT2 genes encoding sugar transporters, SUSY1 encoding a sucrose synthase and several FRK encoding fructokinases. By contrast, the expression of SUC2, SWEET11 and SWEET12, encoding sugar transporters for phloem loading, remained unchanged in the stem. Both the anatomy of vascular tissues and the composition of xylem secondary cell walls were altered, suggesting that high salinity triggered major readjustments of sugar partitioning in this heterotrophic organ. There were changes in the composition of xylem cell walls, associated with the collapse and deformation of xylem vessels. The data are discussed regarding sugar partitioning and homeostasis of sugars in the vascular tissues of the stem
Simulation of the floral transition of the tiller apex to improve the accuracy of grassland phenology modelling
No full textThe heterogeneity in link weights may decrease the robustness of real-world complex weighted networks
No full textHere we report a comprehensive analysis of the robustness of seven high-quality real-world complex weighted networks to errors and attacks toward nodes and links. We use measures of the network damage conceived for a binary (e.g. largest connected cluster LCC, and binary efficiency Effbin) or a weighted network structure (e.g. the efficiency Eff, and the total flow TF). We find that removing a very small fraction of nodes and links with respectively higher strength and weight triggers an abrupt collapse of the weighted functioning measures while measures that evaluate the binary-topological connectedness are almost unaffected. These findings unveil a problematic response-state where the attack toward a small fraction of nodes-links returns the real-world complex networks in a connected but inefficient state. Our findings unveil how the robustness may be overestimated when focusing on the connectedness of the components only. Last, to understand how the networks robustness is affected by link weights heterogeneity, we randomly assign link weights over the topological structure of the real-world networks and we find that highly heterogeneous networks show a faster efficiency decrease under nodes-links removal: i.e. the robustness of the real-world complex networks against nodes-links removal is negatively correlated with link weights heterogeneity
Le Pin d'Alep: évolution, acclimatation et adaptation au changement climatique
No full textL'URFM a participé au colloque BÂTIR DEMAIN AVEC LE PIN D’ALEP: La nouvelle richesse de nos forêts ! qui a eu lieu le vendredi 12 juillet à l'Hotel de Région PACA à Marseille. Cette journée évènement était destiné à l’attention des professionnels et partenaires de la filière forêt-bois, organisée par l’association France Forêt Provence-Alpes-Côte d’Azur avec l’interprofession FIBOIS Sud. Bruno Fady a fait une communication sur les capacités d'adaptation du pin d'Alep au changement climatique et de sa place dans le sud de la France pour la filière bois au 21eme siècle
Explorer les liens entre agriculture, migration et sécurité alimentaire : une enquête auprès de ménages agricoles diversifiés et multilocalisés du nord-ouest du Nicaragua
No full textCet article présente une enquête menée dans le nord-ouest du Nicaragua, qui vise à comprendre comment les flux d’argent et d’aliments générés par les activités diversifiées et multilocalisées des familles agricoles interviennent dans l’accès aux aliments et dans la perception de la sécurité alimentaire. Dans la région d’étude, l’agriculture familiale est caractérisée par des conditions agro-écologiques difficiles et repose sur la production vivrière et l’élevage bovin. En réponse au manque de revenus, les ménages ont depuis longtemps diversifié leurs activités hors exploitation, localement ou en migration. Cette diversification et cette multilocalisation leur permettent d’obtenir des revenus et des aliments, indispensables à la sécurité alimentaire dans les régions d’origine. Ces flux d’argent et d’aliments se fondent sur des rapports sociaux entre les membres des ménages et au-delà (famille élargie, voisinage, acteurs institutionnels). Pour capter ces flux, le questionnaire d’enquête, composé de trois sections, s’organise autour d’une clef d’identification unique : l’individu. En captant les activités individuelles et les flux de ressources dirigés vers la cuisine familiale, l’enquête propose des possibilités d’analyse de la sécurité alimentaire basées sur la déconstruction des unités classiques d’analyse (résidence, ménage, exploitation). Des communautés de production et de circulation sont alors établies pour pouvoir étudier les stratégies d’approvisionnement de la communauté de consommation, point de départ de l’étude de la sécurité alimentaire. Le questionnaire a été appliqué à 350 ménages dans une région d’étude au nord-ouest du Nicaragua. La collecte s’est faite par questionnaire papier et en entretien face-à-face entre avril et juin 2016. Des entretiens individuels complémentaires ont été conduits entre février et mai 2016. Les données ont été saisies entre juillet et octobre 2016, avant d’être contrôlées, nettoyées et préparées pour les analyses entre juin et octobre 2017 sur le logiciel SPSS. Les métadonnées ont été produites sur NESSTAR.This paper presents a survey conducted in northwestern Nicaragua, which aims at understanding how the flows of money and food generated by the diversified and multi-situated activities of farm households intervene in food access and perception of food security. In the study area, family agriculture develops in difficult agro-ecological conditions, and aims at producing staple food production and cattle ranching. In response to the lack of income, farm households have diversified their agricultural production with off-farm activities, locally and in migration. This diversification and multilocation allow them to generate income and food, essential for food security in regions at the origin. Social relationships between household members and beyond (extended family, neighborhood, and institutional actors) structure the flows of money and food. To capture these flows, the survey questionnaire, composed of three sections, is organized around a unique identification key: the individual. By capturing individual activities and resource flows directed towards the family kitchen, the survey offers possibilities for analyzing food security based on the deconstruction of conventional analysis units (residence, household, operation). Production and circulation communities are then established to study the supply strategies of the consumption community, which is the starting point for the analysis of food security. The questionnaire was applied to 350 households in a study area located in the North-west of Nicaragua. Data were gathered by paper questionnaire and face-to-face interview between April and June 2016. Additional individual interviews were conducted between February and May 2016. The data were entered between July and October 2016, before being checked, cleaned and prepared for analysis between June and October 2017 on the SPSS software. The metadata was produced on NESSTAR
Sophie Nicklaus, lauréate du Danone International Prize for Alimentation, pour ses travaux sur le comportement alimentaire des enfants. https://intranet.inra.fr/alimh/Vie-scientifique/Faits-marquants/FM2018
No full textSophie Nicklaus, directrice de recherche Inra au Centre des sciences du goût et de l’alimentation (CSGA) à Dijon est la toute première lauréate du Danone International Prize for Alimentation (DIPA) décerné le 11 juin 2018 à Boston. Elle est récompensée pour ses travaux novateurs sur les comportements alimentaires sains susceptibles de nous amener à repenser la manière dont nous alimentons nos enfants