Parallel declines in species and genetic diversity driven by anthropogenic disturbance: a multispecies approach in a French Atlantic dune system.

Numerous studies assess the correlation between genetic and species diversities, but the processes underlying the observed patterns have only received limited attention. For instance, varying levels of habitat disturbance across a region may locally reduce both diversities due to extinctions, and increased genetic drift during population bottlenecks and founder events. We investigated the regional distribution of genetic and species diversities of a coastal sand dune plant community along 240 kilometers of coastline with the aim to test for a correlation between the two diversity levels. We further quantify and tease apart the respective contributions of natural and anthropogenic disturbance factors to the observed patterns. We detected significant positive correlation between both variables. We further revealed a negative impact of urbanization: Sites with a high amount of recreational infrastructure within 10 km coastline had significantly lowered genetic and species diversities. On the other hand, a measure of natural habitat disturbance had no effect. This study shows that parallel variation of genetic and species diversities across a region can be traced back to human landscape alteration, provides arguments for a more resolute dune protection, and may help to design priority conservation areas

Ultra-porous titanium oxide scaffold with high compressive strength

Highly porous and well interconnected titanium dioxide (TiO2) scaffolds with compressive strength above 2.5 MPa were fabricated without compromising the desired pore architectural characteristics, such as high porosity, appropriate pore size, surface-to-volume ratio, and interconnectivity. Processing parameters and pore architectural characteristics were investigated in order to identify the key processing steps and morphological properties that contributed to the enhanced strength of the scaffolds. Cleaning of the TiO2 raw powder removed phosphates but introduced sodium into the powder, which was suggested to decrease the slurry stability. Strong correlation was found between compressive strength and both replication times and solid content in the ceramic slurry. Increase in the solid content resulted in more favourable sponge loading, which was achieved due to the more suitable rheological properties of the ceramic slurry. Repeated replication process induced only negligible changes in the pore architectural parameters indicating a reduced flaw size in the scaffold struts. The fabricated TiO2 scaffolds show great promise as load-bearing bone scaffolds for applications where moderate mechanical support is required

Household and community socioeconomic and environmental determinants of child nutritional status in Cameroon

BACKGROUND: Undernutrition is a leading cause of child mortality in developing countries, especially in sub-Saharan Africa. We examine the household and community level socioeconomic and environmental factors associated with child nutritional status in Cameroon, and changes in the effects of these factors during the 1990s economic crisis. We further consider age-specific effects of household economic status on child nutrition. METHODS: Child nutritional status was measured by weight-for-age (WAZ) and height-for-age (HAZ) z-scores. Data were from Demographic and Health Surveys conducted in 1991 and 1998. We used analysis of variance to assess the bivariate association between the explanatory factors and nutritional status. Multivariate, multilevel analyses were undertaken to estimate the net effects of both household and community factors. RESULTS: Average WAZ and HAZ declined respectively from -0.70 standard deviations (SD), i.e. 0.70 SD below the reference median, to -0.83 SD (p = 0.006) and from -1.03 SD to -1.14 SD (p = 0.026) between 1991 and 1998. These declines occurred mostly among boys, children over 12 months of age, and those of low socioeconomic status. Maternal education and maternal health seeking behavior were associated with better child nutrition. Household economic status had an overall positive effect that increased during the crisis, but it had little effect in children under 6 months of age. Improved household (water, sanitation and cooking fuel) and community environment had positive effects. Children living in the driest regions of the country were consistently worst off, and those in the largest cities were best off. CONCLUSION: Both household and community factors have significant impact on child health in Cameroon. Understanding these relationships can facilitate design of age- and community-specific intervention programs

Characterization of Granulations of Calcium and Apatite in Serum as Pleomorphic Mineralo-Protein Complexes and as Precursors of Putative Nanobacteria

Calcium and apatite granulations are demonstrated here to form in both human and fetal bovine serum in response to the simple addition of either calcium or phosphate, or a combination of both. These granulations are shown to represent precipitating complexes of protein and hydroxyapatite (HAP) that display marked pleomorphism, appearing as round, laminated particles, spindles, and films. These same complexes can be found in normal untreated serum, albeit at much lower amounts, and appear to result from the progressive binding of serum proteins with apatite until reaching saturation, upon which the mineralo-protein complexes precipitate. Chemically and morphologically, these complexes are virtually identical to the so-called nanobacteria (NB) implicated in numerous diseases and considered unusual for their small size, pleomorphism, and the presence of HAP. Like NB, serum granulations can seed particles upon transfer to serum-free medium, and their main protein constituents include albumin, complement components 3 and 4A, fetuin-A, and apolipoproteins A1 and B100, as well as other calcium and apatite binding proteins found in the serum. However, these serum mineralo-protein complexes are formed from the direct chemical binding of inorganic and organic phases, bypassing the need for any biological processes, including the long cultivation in cell culture conditions deemed necessary for the demonstration of NB. Thus, these serum granulations may result from physiologically inherent processes that become amplified with calcium phosphate loading or when subjected to culturing in medium. They may be viewed as simple mineralo-protein complexes formed from the deployment of calcification-inhibitory pathways used by the body to cope with excess calcium phosphate so as to prevent unwarranted calcification. Rather than representing novel pathophysiological mechanisms or exotic lifeforms, these results indicate that the entities described earlier as NB most likely originate from calcium and apatite binding factors in the serum, presumably calcification inhibitors, that upon saturation, form seeds for HAP deposition and growth. These calcium granulations are similar to those found in organisms throughout nature and may represent the products of more general calcium regulation pathways involved in the control of calcium storage, retrieval, tissue deposition, and disposal

In Vivo Ectopic Implantation Model to Assess Human Mesenchymal Progenitor Cell Potential

Clinical interest on human mesenchymal progenitor cells (hMPC) relies on their potential applicability in cell-based therapies. An in vitro characterization is usually performed in order to define MPC potency. However, in vitro predictions not always correlate with in vivo results and thus there is no consensus in how to really assess cell potency. Our goal was to provide an in vivo testing method to define cell behavior before therapeutic usage, especially for bone tissue engineering applications. In this context, we wondered whether bone marrow stromal cells (hBMSC) would proceed in an osteogenic microenvironment. Based on previous approaches, we developed a fibrin/ceramic/BMP-2/hBMSCs compound. We implanted the compound during only 2 weeks in NOD-SCID mice, either orthotopically to assess its osteoinductive property or subcutaneously to analyze its adequacy as a cell potency testing method. Using fluorescent cell labeling and immunohistochemistry techniques, we could ascertain cell differentiation to bone, bone marrow, cartilage, adipocyte and fibrous tissue. We observed differences in cell potential among different batches of hBMSCs, which did not strictly correlate with in vitro analyses. Our data indicate that the method we have developed is reliable, rapid and reproducible to define cell potency, and may be useful for testing cells destined to bone tissue engineering purposes. Additionally, results obtained with hMPCs from other sources indicate that our method is suitable for testing any potentially implantable mesenchymal cell. Finally, we propose that this model could successfully be employed for bone marrow niche and bone tumor studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12015-013-9464-1) contains supplementary material, which is available to authorized users

Régionalisation du bassin bolivien Amazonien : les hydro-écorégions de la zone des Andes

[Notes_IRSTEA]Numéro spécial "Memorias del congreso Boliviano de Limonologia y recursos acuaticos [Departement_IRSTEA]GMA [TR1_IRSTEA]12 - MILEAU / HYDRECOInternational audienceA global view of the hydrosystems is necessary to define development policies in relation to water problems, but the influence of regional geographic heterogeneity on river ecosystems functioning is still poorly known. We propose here a regionalization of the Andean part of the Bolivian Amazonian drainage basin focusing on running waters systems. The top-down scientific approach is based on the hierarchical control concepts of hydrosystems which recognise as primary control factors the geophysical structure of the basin (geology and geomorphology), and the climate. These factors determine at the reach scale river hydrology, morpho-dynamics and hydro-chemical, characteristics, and the hydrosystem ecological functioning. With this conceptual background, we defined " hydro-ecoregions " (HER), using various maps and satellite data processed with a GIS (geology, geomorphology, digital elevation model, climate, natural vegetation and forested areas, NOAA-NDVI). The HER map is presented, with some examples of the natural features in different regions. HER make up an a priori regional frame, with the hypothesis that in each region rivers will present different physical and biological characteristics.Pou orienter les politiques de développement en fonction des problèmes de l'eau, il est nécessaire d'avoir une vision globale des systèmes aquatiques. Mais l'influence des conditions géographiques régionales sur le fonctionnement écologique des cours d'eau est encore mal connue. Nous proposons une régionalisation dédiée aux cours d'eau de la partie andine du bassin amazonien bolivien. La démarche scientifique se fonde sur les concepts de contrôle hiérarchique des hydrosystèmes, qui reconnaissent comme déterminants primaires la structure physique des bassins (géologie et géomorphologie), et le climat. Ces facteurs déterminent à l'échelle locale l'hydrologie, la morpho-dynamique et la chimie des tronçons, et donc leur fonctionnement écologique. Sur ces bases ont été définies des hydro-écorégions (HER) en utilisant grace à un SIG des cartes et images satellitaires existantes (géologie, géomorphologie, modèle numérique de terrain, climat, végétation naturelle et forêts, indice NDVI). La carte des HER est présentée avec des exemples de variations de leurs caractéristiques naturelles. Les HER constituent une régionalisation a priori, avec l'hypothèse que dans chaque région les cours d'eau présenteront des caractéristiques physiques et biologiques différentes

TD peptide as an adjunct of reperfusion therapy provides long-term cardioprotective effects in a mouse model of ischemia-reperfusion

International audienceIntroduction: During myocardial infarction (MI), reperfusion therapy leads to side effects called ischemia-reperfusion (IR) injury for which no treatment exists. While most studies have targeted the intrinsic apoptotic pathway to prevent IR injury with no successful clinical translation, we have developed a cardioprotective tool, the anti-apoptotic Tat-DAXXp (TD) peptide, targeting the FAS-dependent extrinsic pathway and recently evidenced as a potent therapeutic molecule.Objective: The aim of the present study was to evaluate TD long term cardioprotective effects in a mouse model of reperfused infarction.Methods: TD peptide was evaluated in a mouse model of myocardial infarction (40 minutes ischemia) followed by reperfusion and 6 month-follow up. TD peptide (1 mg/kg) was administered in mice subjected to MI (TD; n=21), 5 min prior to reperfusion. Cardiac injury in the study cohort was assessed by the quantification of cardiac Troponin I levels at 24h post-MI and each month of the period. Preclinical evaluation was performed by the mean of echocardiographic follow-up using both conventional and strain parameters. An histological analysis was performed at the end of the protocol for the quantification of fibrosis extend.Results Plasma cTnI concentration evaluated 24 h post-MI was 70%-decreased in TD (n=16) versus Ctrl (n=20) mice (p***). Strain echocardiography highlighted a 24%-increase (p****) in the ejection fraction mean value in TD-treated (n=12) versus Ctrl mice (n=17) during the 6 month-period. Improved cardiac performance was associated to a 54%-decrease (p**) in left ventricular fibrosis at 6 months in TD (n=16) versus Ctrl (n=20).Conclusion:Targeting the extrinsic pathway with the TD peptide at the onset of reperfusion provided long term cardioprotection in a mouse model of myocardial reperfused infarction by improving post-MI cardiac performance and preventing cardiac remodeling