31 research outputs found

    Using web and mobile phone technologies to collect food market prices in Africa. Approaching real-time data and use of crowdsourcing, 2013 - 2016

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    Large agricultural commodity price swings observed in recent years have made the importance of accessible, timely, accurate and frequently updated price data more obvious. This study investigates the potential of innovative web and mobile phone technologies and alternative data collection methods such as crowdsourcing in order to collect food price data in Africa. The report summarises these experiences through the lessons learned and provides a detailed overview and assessment of different aspects of the collected data that can be of help for the success of future food price collection exercises.JRC.D.4-Economics of Agricultur

    Apoplastic recognition of multiple candidate effectors from the wheat pathogen Zymoseptoria tritici in the nonhost plant Nicotiana benthamiana

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    The fungus Zymoseptoria tritici is a strictly apoplastic, host-specific pathogen of wheat leaves and causal agent of septoria tritici blotch (STB) disease. All other plants are considered nonhosts, but the mechanism of nonhost resistance (NHR) to Z. tritici has not been addressed previously. We sought to develop Nicotiana benthamiana as a system to study NHR against Z. tritici. Fluorescence microscopy and quantitative reverse transcription polymerase chain reactions were used to establish the interaction between Z. tritici and N. benthamiana. Agrobacteriummediated transient expression was used to screen putative Z. tritici effector genes for recognition in N. benthamiana, and virus-induced gene silencing (VIGS) was employed to determine the role of two receptor-like kinases (RLKs), NbBAK1 and NbSOBIR1, in Z. tritici effector recognition. Numerous Z. tritici putative effectors (14 of 63 tested) induced cell death or chlorosis in N. benthamiana. For most, phenotypes were light-dependent and required effector secretion to the leaf apoplastic space. Moreover, effector-induced host cell death was dependent on NbBAK1 and NbSOBIR1. Our results indicate widespread recognition of apoplastic effectors from a wheat-infecting fungal pathogen in a taxonomically distant nonhost plant species presumably by cell surface immune receptors. This suggests that apoplastic recognition of multiple nonadapted pathogen effectors may contribute to NHR

    Numerical modeling of hydrodynamic circulation in Ichkeul Lake-Tunisia

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    The Ichkeul Lake ecosystem, Northern of Tunisia, has been registered as a biosphere reserve in 1977 (MAB-UNESCO Convention), a UNESCO World Heritage site in 1979, and a RAMSAR site in 1980. Damming and global warming drought drastically diminished the fresh water supply to this lake. This leads to water level and salinity fluctuation throughout the year. Consequently, the water clarity of this shallow wind-stressed lake was altered and if this siltation continues to increase, will seriously affects the hydromorphology and ecology of this wetland. Therefore, to study the hydrodynamic water circulation in the lake and the transport of the Total Suspend Matter (TSM), hydrodynamic and transport models were calibrated and applied to this environment. Numerical model predictions based on water level, temperature and salinity sensitivity to the bed roughness show that the Delft 3D-Flow model reproduced well the measured data with RMSE < 0.027 for water level

    Sample Management: Recommendation for best practices and harmonization from the Global Bioanalysis Consortium Harmonization Team

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    The regulations do not contain much guidance on sample management; however this is a very important aspect in regulatory work. A balanced team was formed to discuss the aspects involved and to put forward recommendations. Sampling conditions should be described in the protocol and in the laboratory manual. Items to be described include volume, anticoagulant, protection from light, labelling. The correct procedures for storing the samples at the clinical site and for shipment of the samples are also very important, along with the accompanying information. The chain of custody for the samples must be maintained throughout the complete lifespan of each sample. Therefore storage location and conditions must also be clearly defined at the analytical lab, pre and post analysis. A transparent way to do this is via a LIMS. The storage temperature of the samples must be traceable and controlled, via freezer monitoring. The team suggests to move away from using temperatures to define the storage condition, but rather move to a standard convention of room temperature, refrigerator, freezer and ultra-freeze

    Solution structure of Pi4, a short four-disulfide-bridged scorpion toxin specific of potassium channels

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    Pi4 is a short toxin found at very low abundance in the venom of Pandinus imperator scorpions. It is a potent blocker of K+ channels. Like the other members of the α-KTX6 subfamily to which it belongs, it is cross-linked by four disulfide bonds. The synthetic analog (sPi4) and the natural toxin (nPi4) have been obtained by solid-phase synthesis or from scorpion venom, respectively. Analysis of two-dimensional 1H NMR spectra of nPi4 and sPi4 indicates that both peptides have the same structure. Moreover, electrophysiological recordings of the blocking of Shaker B K+ channels by sPi4 (KD = 8.5 nM) indicate that sPi4 has the same blocking activity of nPi4 (KD = 8.0 nM), previously described. The disulfide bonds have been independently determined by NMR and structure calculations, and by Edman-degradation/mass-spectrometry identification of peptides obtained by proteolysis of nPi4. Both approaches indicate that the pairing of the half-cystines is 6C–27C, 12C–32C, 16C–34C, and 22C–37C. The structure of the toxin has been determined by using 705 constraints derived from NMR data on sPi4. The structure, which is well defined, shows the characteristic α/β scaffold of scorpion toxins. It is compared to the structure of the other α-KTX6 subfamily members and, in particular, to the structure of maurotoxin, which shows a different pattern of disulfide bridges despite its high degree of sequence identity (76%) with Pi4. The structure of Pi4 and the high amounts of synthetic peptide available, will enable the detailed analysis of the interaction of Pi4 with K+ channels

    Transposition of a Fungal Miniature Inverted-Repeat Transposable Element Through the Action of a Tc1-Like Transposase

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    The mimp1 element previously identified in the ascomycete fungus Fusarium oxysporum has hallmarks of miniature inverted-repeat transposable elements (MITEs): short size, terminal inverted repeats (TIRs), structural homogeneity, and a stable secondary structure. Since mimp1 has no coding capacity, its mobilization requires a transposase-encoding element. On the basis of the similarity of TIRs and target-site preference with the autonomous Tc1-like element impala, together with a correlated distribution of both elements among the Fusarium genus, we investigated the ability of mimp1 to jump upon expression of the impala transposase provided in trans. Under these conditions, we present evidence that mimp1 transposes by a cut-and-paste mechanism into TA dinucleotides, which are duplicated upon insertion. Our results also show that mimp1 reinserts very frequently in genic regions for at least one-third of the cases. We also show that the mimp1/impala double-component system is fully functional in the heterologous species F. graminearum, allowing the development of a highly efficient tool for gene tagging in filamentous fungi
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