Physical training and hypertension have opposite effects on endothelial brain-derived neurotrophic factor expression

Aims Changes in circulating brain-derived neurotrophic factor (BDNF) levels were reported in patients with or at risk for cardiovascular diseases associated with endothelial dysfunction, suggesting a link between BDNF and endothelial functionality. However, little is known on cardiovascular BDNF. Our aim was to investigate levels/localization, function, and relevance of cardiovascular BDNF. Methods and results BDNF levels (western blotting) and localization (immunostaining) were assessed in the heart and aorta from rats with impaired (spontaneously hypertensive rats [SHR]), normal (Wistar Kyoto rats [WKY]), and improved (SHR and WKY subjected to physical training) endothelial function. BDNF levels were also measured in cultured endothelial cells (CECs) subjected to low and high shear stress. The cardiovascular effects of BDNF were investigated in isolated aortic rings and hearts. The results showed high BDNF levels in the heart and aorta, the expression being prominent in endothelial cells as compared with other cell types. Exogenous BDNF vasodilated aortic rings but changed neither coronary flow nor cardiac contractility. Hypertension was associated with decreased expression of BDNF in the endothelium, whereas physical training led to endothelial BDNF up-regulation not only in WKY but also in SHR. Exposure of CECs to high shear stress stimulated BDNF production and secretion. Conclusion Cardiovascular BDNF is mainly localized within endothelial cells in which its expression is dependent on endothelial function. These results open new perspectives on the role of endothelial BDNF in cardiovascular healt

Evaluation of genetic isolation within an island flora reveals unusually widespread local adaptation and supports sympatric speciation

It is now recognized that speciation can proceed even when divergent natural selection is opposed by gene flow. Understanding the extent to which environmental gradients and geographical distance can limit gene flow within species can shed light on the relative roles of selection and dispersal limitation during the early stages of population divergence and speciation. On the remote Lord Howe Island (Australia), ecological speciation with gene flow is thought to have taken place in several plant genera. The aim of this study was to establish the contributions of isolation by environment (IBE) and isolation by community (IBC) to the genetic structure of 19 plant species, from a number of distantly related families, which have been subjected to similar environmental pressures over comparable time scales. We applied an individual-based, multivariate, model averaging approach to quantify IBE and IBC, while controlling for isolation by distance (IBD). Our analyses demonstrated that all species experienced some degree of ecologically driven isolation, whereas only 12 of 19 species were subjected to IBD. The prevalence of IBE within these plant species indicates that divergent selection in plants frequently produces local adaptation and supports hypotheses that ecological divergence can drive speciation in sympatry

An optimized protocol for microarray validation by quantitative PCR using amplified amino allyl labeled RNA

<p>Abstract</p> <p>Background</p> <p>Validation of microarrays data by quantitative real-time PCR (qPCR) is often limited by the low amount of available RNA. This raised the possibility to perform validation experiments on the amplified amino allyl labeled RNA (AA-aRNA) leftover from microarrays. To test this possibility, we used an ongoing study of our laboratory aiming at identifying new biomarkers of graft rejection by the transcriptomic analysis of blood cells from brain-dead organ donors.</p> <p>Results</p> <p>qPCR for ACTB performed on AA-aRNA from 15 donors provided Cq values 8 cycles higher than when original RNA was used (P < 0.001), suggesting a strong inhibition of qPCR performed on AA-aRNA. When expression levels of 5 other genes were measured in AA-aRNA generated from a universal reference RNA, qPCR sensitivity and efficiency were decreased. This prevented the quantification of one low-abundant gene, which was readily quantified in un-amplified and un-labeled RNA. To overcome this limitation, we modified the reverse transcription (RT) protocol that generates cDNA from AA-aRNA as follows: addition of a denaturation step and 2-min incubation at room temperature to improve random primers annealing, a transcription initiation step to improve RT, and a final treatment with RNase H to degrade remaining RNA. Tested on universal reference AA-aRNA, these modifications provided a gain of 3.4 Cq (average from 5 genes, P < 0.001) and an increase of qPCR efficiency (from -1.96 to -2.88; P = 0.02). They also allowed for the detection of a low-abundant gene that was previously undetectable. Tested on AA-aRNA from 15 brain-dead organ donors, RT optimization provided a gain of 2.7 cycles (average from 7 genes, P = 0.004). Finally, qPCR results significantly correlated with microarrays.</p> <p>Conclusion</p> <p>We present here an optimized RT protocol for validation of microarrays by qPCR from AA-aRNA. This is particularly valuable in experiments where limited amount of RNA is available.</p

3D Imaging on heterogeneous surfaces on laterite drill core materials

The SOLSA project aims to construct an analytical expert system for on-line-on-mine-real-time mineralogical and geochemical analyses on sonic drilled cores. A profilometer is indispensable to obtain reliable and quantitative data from RGB and hyperspectral cameras, and to get 3D definition of close-to-surface objects such as rheology (grain shape, grain size, fractures and vein systems), material hardness and porosities. Optical properties of minerals can be analyzed by focusing on the reflectance. Preliminary analyses were performed with the commercial scan control profilometer MI-CRO-EPSILON equipped with a blue 405 nm laser on a conveyor belt (depth resolution: 10 μm; surface resolution: 30x30 μm2 (maximum resolution; 1m drill core/4 min). Drill core parts and rocks with 4 different surface roughness states: (1) sonic drilled, (2) diamond saw-cut, polished at (3) 6 mm and (4) 0.25 μm were measured (see also abstract Duée et al. this volume). The ΜICRO- EPSILON scanning does not detect such small differences of surface roughness states. Profilometer data can also be used to access rough mineralogical identification of some mineral groups like Fe-Mg silicates, quartz and feldspars). Drill core parts from a siliceous mineralized breccia and laterite with high and deep porosity and fractures were analyzed. The determination of holes’ convexity and fractures) is limited by the surface/depth ratio. Depending on end-user’s needs, parameters such as fracture densities and mineral content should be combined, and depth and surface resolutions should be optimized, to speed up “on-line-on-mine-real- time” mineral and chemical analyses in order to reach the target of about 80 m/day of drilled core

Efficient long-term open-access data archiving in mining industries

Efficient data collection, analysis and preservation are needed to accomplish adequate business decision making. Long-lasting and sustainable business operations, such as mining, add extra requirements to this process: data must be reliably preserved over periods that are longer than that of a typical software life-cycle. These concerns are of special importance for the combined on-line-on-mine-real-time expert system SOLSA (http://www.solsa-mining.eu/) that will produce data not only for immediate industrial utilization, but also for the possible scientific reuse. We thus applied the experience of scientific data publishing to provide efficient, reliable, long term archival data storage. Crystallography, a field covering one of the methods used in the SOLSA expert system, has long traditions of archiving and disseminating crystallographic data. To that end, the Crystallographic Interchange Framework (CIF, [1]) was developed and is maintained by the International Union of Crystallography (IUCr). This framework provides rich means for describing crystal structures and crystallographic experiments in an unambiguous, human- and machine- readable way, in a standard that is independent of the underlying data storage technology. The Crystallography Open Database (COD, [2]) has been successfully using the CIF framework to maintain its open-access crystallographic data collection for over a decade [3,4]. Since the CIF framework is extensible it is possible to use it for other branches of knowledge. The SOLSA system will generate data using different methods of material identification: XRF, XRD, Raman, IR and DRIFT spectroscopy. For XRD, the CIF is usable out-of-the-box, since we can rely on extensive data definition dictionaries (ontologies) developed by the IUCr and the crystallographic community. For spectroscopic techniques such dictionaries, to our best knowledge, do not exist; thus, the SOLSA team is developing CIF dictionaries for spectroscopic techniques to be used in the SOLSA expert system. All dictionaries will be published under liberal license and communities are encourage to join the development, reuse and extend the dictionaries where necessary. These dictionaries will enable access to open data generated by SOLSA by all interested parties. The use of the common CIF framework will ensure smooth data exchange among SOLSA partners and seamless data publication from the SOLSA project

Modélisation et estimation de la dispersion efficace du pollen de colza à longue distance, dans un paysage agricole et dans un champ

DANS CETTE ETUDE, DES MODELES STATISTIQUES DE DISPERSION DE POLLEN DE COLZA ONT ETE CONSTRUITS POUR ESTIMER LA POLLINISATION A LONGUE DISTANCE.CETTE ESTIMATION S'EST FAITE EN AJUSTANT DES FONCTIONS DE DISPERSION INDIVIDUELLE QUI DECRIVENT LA PROBABILITE QU'UN GRAIN DE POLLEN FECONDE UNE PLANTE A UNE DISTANCE DONNEE, A PARTIR DE DONNEES RECOLTEES DANS UN BASSIN DE PRODUCTION ( LOIR-ET-CHER, 100KM CONTENANT 170 CHAMPS). DES PLANTES MALE-STERILES ONT ETE PLACEES DANS CE BASSIN POUR ECHANTILLONNER DES GRAINS DE POLLEN DONT LES GENOTYPES ONT ETE ULTERIEUREMENT DETERMINES GRACE A DES MARQUEURS MICROSATELLITES. L'AJUSTEMENT DES FONCTIONS A ETE REALISE EN MAXIMISANT LA VRAISEMBLANCE DES DONNEES GENETIQUES SOUS L'HYPOTHESE D'UN MODELE DE D'APPARIEMENT.LES RESULTAT DE CETTE ETUDE ONT MONTRE QUE (1) LES NUAGES POLLINIQUES ECHANTILLONNES PRESENTENT UNE FORTE DIVERSITE ET UNE FORTE DIFFERENCIATION, (2) CES NUAGES PROVIENNENT DES CHAMPS PROCHES MAIS EGALEMENT DISTANTS (PLUSIEURS CENTAINES DE METRES) DES SITES D'ECHANTILLONNAGE ET (3) LA MOITIE DE CES NUAGES PROVIENT DE SOURCES DE POLLEN DONT LA POSITION ET LA NATURE N'ONT PAS PU ETRE DETERMINEES PRECISEMENT.LA MEILLEURE FONCTION DE DISPERSION INDIVIDUELLE (GEOMETRIQUE) AJUSTEE AUX DONNEES DE CETTE ETUDE PREDIT UNE FORTE PROPORTION DE POLLINISATION A LONGUE DISTANCE, PLUS FORTE QUE LES FONCTIONS EXPONENTIELLES COURAMMENT UTILISEES ET PLUS FORTE QUE LES FONCTIONS DE DISPERSION PRECEDEMMENT AJUSTEES A L'ECHELLE D'UN CHAMP. LA FONCTION AJUSTEE ICI A ENSUITE ETE (PARTIELLEMENT) VALIDEE EN PREDISANT LES TAUX DE POLLINISATION CROISEE OBSERVES DANS DOUZE DISPOSITIFS CANADIENS COMPRENANT DES CHAMPS DE PLUSIEURS DIZAINES D'HECTARES.THIS STUDY AIMED AT BUILDING SPATIALLY EXPLICIT MODELS OF OILSEED RAPE POLLEN DISPERSAL TO ESTIMATE DISPERSAL KERNELS AND CONCLUDE ON THE PROPORTION OF LONG-DISTANCE POLLINATION.THESE DISPERSAL KERNELS, THAT DESCRIBE THE PROBABILITY OF A POLLEN GRAIN TO FERTILIZE A PLANT AT A GIVEN DISTANCE, WERE ESTIMATED USING DATA COLLECTED IN A FRENCH PRODUCTION AREA (SELOMMES, LOIR-ET-CHER) OF 100 KM AND CONTAINING 170 OILSEED RAPE FIELDS. FIRST MALE-STERILE PLANTS WERE SCATTERED IN THE STUDY AREA TO COLLECT POLLEN GRAINS. THEN THE GENOTYPES OF THESE POLLEN GRAINS WERE RETRIEVED USING MICROSATELLITE MARKERS. DISPERSAL KERNELS WERE ESTIMATED BY MAXIMISING THE LIKELIHOOD OF THE GENETIC DATA UNDER A MATING MODEL ADAPTED TO CULTIVATED SPECIES.RESULTS OF THIS STUDY SHOWED THAT (1) SAMPLED POLLEN CLOUDS WERE DIVERSE AND DIFFERENTIATED, (2) THESE POLLEN CLOUDS ORIGINATED FROM CLOSE AND DISTANT FIELDS (SEVERAL HUNDRED METERS) AND (3) HALF OF THE POLLEN CLOUDS ORIGINATED FROM POLLEN SOURCES WHOSE POSITION AND COMPOSITION COULD NOT BE PRECISELY DETERMINED.THE BEST-FITTED DISPERSAL KERNEL IN THIS STUDY (GEOMETRIC) PREDICTS MUCH MORE LONG-DISTANCE POLLINATION THAN THE EXPONENTIAL FUNCTIONS THAT ARE COMMONLY USED AND THAN DISPERSAL KERNELS THAT WERE PREVIOUSLY FITTED WITHIN A FIELD. THE BEST-FITTED KERNEL HERE WAS THEN (PARTIALLY) VALIDATED BY USING IT TO PREDICT CROSS-POLLINATION RATES OBSERVED IN TWELVE CANADIAN SITES CONSISTING OF COMMERCIAL FIELDS OF SEVERAL HUNDRED HECTARES.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Assortative mating can help adaptation of flowering time to a changing climate: insights from a polygenic model

Several empirical studies report fast evolutionary changes in flowering time in response to contemporary climate change. Flowering time is a polygenic trait under assortative mating, since flowering time of mates must overlap. Here we test whether assortative mating, compared to random mating, can help better track a changing climate. For each mating pattern, our individual-based model simulates a population evolving in a climate characterized by stabilizing selection around an optimal flowering time, which can change directionally and/or fluctuate. We also derive new analytical predictions from a quantitative genetics model for the expected genetic variance at equilibrium, and its components, the lag of the population to the optimum, and the population mean fitness. We compare these predictions between assortative and random mating, and to our simulation results. Assortative mating, compared to random mating, has antagonistic effects on genetic variance: it generates positive associations among similar allelic effects, which inflates the genetic variance, but it decreases genetic polymorphism, which depresses the genetic variance. In a stationary environment with substantial stabilizing selection, assortative mating affects little the genetic variance compared to random mating. In a changing climate, assortative mating however increases genetic variance compared to random mating, which diminishes the lag of the population to the optimum, and in most scenarios translates into a fitness advantage relative to random mating. The magnitude of this fitness advantage depends on the extent to which genetic variance limits adaptation, being larger for faster environmental changes and weaker stabilizing selection.Please contact the corresponding author for the notebook (.nb) simulating the evolution of populations under assortative and random mating

Vulnérabilité du territoire national aux risques littoraux

«Vulnerability of the French national territory to coastal risks » is a study led by CETMEF in close collaboration with two French public engineering agencies (CETE Méditerranée and CETE de l''Ouest). The main objectives were to summarize coastal hazards vulnerability knowledge and to map and estimate the expanse of the current French areas vulnerable to coastal hazards. This assessment is necessary to estimate climate change impacts. The first part of the study, run in 2008-2009, was about metropolitan France and the second part, run in 2010-2011, is about French overseas territory. Firstly the main regional-scaled studies were summarized to give general trends. Secondly different risk indicators, based on the analysis of public national databases (national statement of natural disaster, extreme sea level and elements at risk as constructions, infrastructures or protected areas...), were determined, mapped and combined to quantify vulnerability. Towns vulnerability to coastal risks is mapped. This map confirms the territories already known as vulnerable (north of France, Somme bay, Pays de Loire, Charente-Maritime islands and Languedoc-Roussillon) and allows to compare them. Most of the vulnerable territories are located in Metropolitan France.«Vulnérabilité du territoire national aux risques littoraux » est une étude menée par le CETMEF en collaboration avec les CETE Méditerranée et CETE de l''Ouest. Les principaux objectifs étaient de faire une synthèse des connaissances sur la vulnérabilité aux risques côtiers et d''établir une représentation cartographique des secteurs vulnérables en France. Cette évaluation est nécessaire pour estimer les impacts du changement climatique. La première partie de l''étude, menée entre 2008 et 2009, s''est concentrée sur la métropole et la seconde partie, menée entre 2010 et 2011, a concerné l''Outre-Mer. Les principales études régionales et départementales ont fait l''objet d''une synthèse bibliographique. La détermination de différents indicateurs, basés sur l''analyse de bases de données disponibles au niveau national (arrêtés de déclaration de l''état de catastrophe naturelle, niveaux marins extrêmes, BD Topo ® IGN et enjeux, dont bâti, infrastructures de transport, établissements Seveso et réseau Natura 2000), a permis de quantifier la vulnérabilité et de réaliser de nombreuses cartes de synthèse. La cartographie de la vulnérabilité de chaque commune française aux risques littoraux permet d''identifier certains secteurs très vulnérables, confirmant ce qui était déjà constaté au niveau national, et de pouvoir les comparer. Ressortent ainsi par exemple le littoral de la façade Nord, la Baie de Somme, les Pays de la Loire, les îles de Charente-Maritime et le Languedoc-Roussillon. Il apparaît que la majorité des secteurs très vulnérables sont situés en métropole.Perherin Céline, Roche Amélie, Trmal Celine, Roux Isabelle, Pons Frédéric, Boura Céline, Devaux Emmanuel, Désiré Guy. Vulnérabilité du territoire national aux risques littoraux. In: Evénements extrêmes fluviaux et maritimes. Leurs variabilités spatiales et chronologiques dans l'ouest de l’Europe. 34èmes journées de l’hydraulique Paris, 1 et 2 février 2012. 2012