180 research outputs found

    Bilan de la recherche agricole et agroalimentaire au Sénégal

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    Neutrons describe ectoine effects on water H-bonding and hydration around a soluble protein and a cell membrane

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    Understanding adaptation to extreme environments remains a challenge of high biotechnological potential for fundamental molecular biology. The cytosol of many microorganisms, isolated from saline environments, reversibly accumulates molar concentrations of the osmolyte ectoine to counterbalance fluctuating external salt concentrations. Although they have been studied extensively by thermodynamic and spectroscopic methods, direct experimental structural data have, so far, been lacking on ectoine-water-protein interactions. In this paper, in vivo deuterium labeling, small angle neutron scattering, neutron membrane diffraction and inelastic scattering are combined with neutron liquids diffraction to characterize the extreme ectoine-containing solvent and its effects on purple membrane of H. salinarum and E. coli maltose binding protein. The data reveal that ectoine is excluded from the hydration layer at the membrane surface and does not affect membrane molecular dynamics, and prove a previous hypothesis that ectoine is excluded from a monolayer of dense hydration water around the soluble protein. Neutron liquids diffraction to atomic resolution shows how ectoine enhances the remarkable properties of H-bonds in water-properties that are essential for the proper organization, stabilization and dynamics of biological structures

    Analysis of pfhrp2 genetic diversity in Senegal and implications for use of rapid diagnostic tests

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    Background: The Senegalese National Malaria Control Programme has recommended use of rapid diagnostic tests (RDTs) that target the histidine-rich protein 2 (HRP2), specific to Plasmodium falciparum, to diagnose malaria cases. The target antigen has been shown to be polymorphic, which may explain the variability in HRP2-based RDT results reported in field studies. The genetic diversity of the pfhrp2 gene has not been investigated in depth in many African countries. The goal of this study is to determine the extent of polymorphism in pfhrp2 among Senegal, Mali and Uganda parasite populations, and discuss the implications of these findings on the utility of RDTs that are based on HRP2 detection. Methods: Sequencing data from the pfhrp2 locus were used to analyze the genetic diversity of this gene among three populations, with different transmission dynamics and malaria parasite ecologies. Nucleotide diversity (π) and non-synonymous nucleotide diversity (πNS) were studied in the pfhrp2 gene from isolates obtained in Senegal. Amino acid repeat length polymorphisms in the PfHRP2 antigen were characterized and parameters of genetic diversity, such as frequency and correlation between repeats in these populations, were assessed. Results: The diversity survey of the pfhrp2 gene identified 29 SNPs as well as insertion and deletion polymorphisms within a 918 bp region. The Senegal pfhrp2 exhibited a substantial level of diversity [π = 0.00559 and πNS = 0.014111 (πS = 0.0291627)], similar to several polymorphic genes, such as msp1, involved in immune responses, and the gene encoding the SURFIN polymorphic antigen, which are surface exposed parasite proteins. Extensive repeat length polymorphisms in PfHRP2, as well as similar patterns in the number, organization and the type of predicted amino acid repeats were observed among the three populations, characterized by an occurrence of Type 2, Type 4 and Type 7 repeats. Conclusions: These results warrant deeper monitoring of the RDT target antigen diversity and emphasize that development of other essential genes as a target for diagnostic tools is critical

    Exchange of Best Practices Within the European Union:Surgery Standardization of Abdominal Organ Retrieval

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    AbstractConsidering the growing organ demand worldwide, it is crucial to optimize organ retrieval and training of surgeons to reduce the risk of injury during the procedure and increase the quality of organs to be transplanted. In the Netherlands, a national complete trajectory from training of surgeons in procurement surgery to the quality assessment of the procured organs was implemented in 2010. This mandatory trajectory comprises training and certification modules: E-learning, training on the job, and a practical session. Thanks to the ACCORD (Achieving Comprehensive Coordination in Organ Donation) Joint Action coordinated by Spain and co-funded under the European Commission Health Programme, 3 twinning activities (led by France) were set to exchange best practices between countries. The Dutch trajectory is being adapted and implemented in Hungary as one of these twinning activities. The E-learning platform was modified, tested by a panel of Hungarian and UK surgeons, and was awarded in July 2013 by the European Accreditation Council for Continuing Medical Education of the European Union of Medical Specialists. As a pilot phase for future national training, 6 Hungarian surgeons from Semmelweis University are being trained; E-learning platform was fulfilled, and practical sessions, training-on-the-job activities, and evaluations of technical skills are ongoing. The first national practical session was recently organized in Budapest, and the new series of nationwide selected candidates completed the E-learning platform before the practical. There is great potential for sharing best practices and for direct transfer of expertise at the European level, and especially to export this standardized training in organ retrieval to other European countries and even broader. The final goal was to not only provide a national training to all countries lacking such a program but also to improve the quality and safety criteria of organs to be transplanted

    Composition and Distribution of Mosquito Vectors in a Peri-Urban Community Surrounding an Institution of Learning in Lafia Metropolis, Nasarawa State, Central Nigeria

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    Vector surveillance is very key in solving mosquito-borne health problems in Nigeria. To this end, the composition and distribution of mosquito vectors in a peri-urban community surrounding an institution of learning in Lafia metropolis, Nasarawa State, Central Nigeria was carried out between December 2016 and June 2017. The Prokopack Aspirator was used to collect indoor resting mosquitoes between 6:00 a.m. and 9:00 a.m. from 30 randomly selected houses. Mosquitoes collected were knocked down and transferred into a well labelled petri-dish and taken to the laboratory for processing. A total of 664 mosquitoes were collected which spread across Culex quinquefasciatus 572 (86.14%), Anopheles gambiae 88 (13.25%) and Aedes aegypti 4 (0.60%). The abundance of mosquitoes in relation to seasons, species, sex, abdominal conditions as well as transmission indices across seasons significantly varied (P 0.05). The inhabitants of the area should ensure that all drainages flow through so as to reduce mosquito breeding grounds. Also, members of the community should always protect themselves by sleeping under insecticide treated bed nets

    Resilience from the ground up: how are local resilience perceptions and global frameworks aligned?

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    Numerous resilience measurement frameworks for climate programmes have emerged over the past decade to operationalise the concept and aggregate results within and between programmes. Proxies of resilience, including subjective measures using perception data, have been proposed to measure resilience, but there is limited evidence on their validity and use for policy and practice. This article draws on research on the Decentralising Climate Funds project of the Building Resilience and Adaptation to Climate Extremes and Disasters programme, which supports communities in Mali and Senegal to improve climate resilience through locally controlled adaptation funds. It explores attributes of resilience from this bottom‐up perspective to assess its predictors and alignment with food security, as a proxy of well‐being. We find different patterns when comparing resilience and the well‐being proxy, illustrating that the interplay between the two is still unclear. Results also point to the importance of contextualising resilience, raising implications for aggregating results

    West Africa International Centers of Excellence for Malaria Research: Drug Resistance Patterns to Artemether-Lumefantrine in Senegal, Mali, and The Gambia.

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    In 2006, artemether-lumefantrine (AL) became the first-line treatment of uncomplicated malaria in Senegal, Mali, and the Gambia. To monitor its efficacy, between August 2011 and November 2014, children with uncomplicated Plasmodium falciparum malaria were treated with AL and followed up for 42 days. A total of 463 subjects were enrolled in three sites (246 in Senegal, 97 in Mali, and 120 in Gambia). No early treatment failure was observed and malaria infection cleared in all patients by day 3. Polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) was 100% in Mali, and the Gambia, and 98.8% in Senegal. However, without PCR adjustment, ACPR was 89.4% overall; 91.5% in Mali, 98.8% in Senegal, and 64.3% in the Gambia (the lower value in the Gambia attributed to poor compliance of the full antimalarial course). However, pfmdr1 mutations were prevalent in Senegal and a decrease in parasite sensitivity to artesunate and lumefantrine (as measured by ex vivo drug assay) was observed at all sites. Recrudescent parasites did not show Kelch 13 (K13) mutations and AL remains highly efficacious in these west African sites

    Allelic diversity of MSP1 and MSP2 repeat loci correlate with levels of malaria endemicity in Senegal and Nigerian populations.

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    BACKGROUND: Characterizing the genetic diversity of malaria parasite populations in different endemic settings (from low to high) could be helpful in determining the effectiveness of malaria interventions. This study compared Plasmodium falciparum parasite population diversity from two sites with low (pre-elimination) and high transmission in Senegal and Nigeria, respectively. METHODS: Parasite genomic DNA was extracted from 187 dried blood spot collected from confirmed uncomplicated P. falciparum malaria infected patients in Senegal (94) and Nigeria (93). Allelic polymorphism at merozoite surface protein 1 (msp1) and merozoite surface protein- 2 (msp2) genes were assessed by nested PCR. RESULTS: The most frequent msp1 and msp2 allelic families are the K1 and IC3D7 allelotypes in both Senegal and Nigeria. Multiplicity of infection (MOI) of greater that 1 and thus complex infections was common in both study sites in Senegal (Thies:1.51/2.53; Kedougou:2.2/2.0 for msp1/2) than in Nigeria (Gbagada: 1.39/1.96; Oredo: 1.35/1.75]). The heterozygosity of msp1 gene was higher in P. falciparum isolates from Senegal (Thies: 0.62; Kedougou: 0.53) than isolates from Nigeria (Gbagada: 0.55; Oredo: 0.50). In Senegal, K1 alleles was associated with heavy than with moderate parasite density. Meanwhile, equal proportions of K1 were observed in both heavy and moderate infection types in Nigeria. The IC3D7 subtype allele of the msp2 family was the most frequent in heavily parasitaemic individuals from both countries than in the moderately infected participants. CONCLUSION: The unexpectedly low genetic diversity of infections high endemic Nigerian setting compared to the low endemic settings in Senegal is suggestive of possible epidemic outbreak in Nigeria
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