8 research outputs found

    Crystallization and preliminary X-ray study of Vibrio cholerae uridine phosphorylase in complex with 6-methyluracil

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    Uridine phosphorylase catalyzes the phosphorolysis of ribonucleosides, with the nitrogenous base and ribose 1-phosphate as products. Additionally, it catalyzes the reverse reaction of the synthesis of ribonucleosides from ribose 1-phosphate and a nitrogenous base. However, the enzyme does not catalyze the synthesis of nucleosides when the substrate is a nitrogenous base substituted at the 6-­position, such as 6-methyluracil (6-MU). In order to explain this fact, it is essential to investigate the three-dimensional structure of the complex of 6-MU with uridine phosphorylase. 6-MU is a pharmaceutical agent that improves tissue nutrition and enhances cell regeneration by normalization of nucleotide exchange in humans. 6-MU is used for the treatment of diseases of the gastrointestinal tract, including infectious diseases. Here, procedures to obtain the uridine phosphorylase from the pathogenic bacterium Vibrio cholerae (VchUPh), purification of this enzyme, crystallization of the complex of VchUPh with 6-MU, and X-ray data collection and preliminary X-ray analysis of the VchUPh-6-MU complex at atomic resolution are reported

    Indicator Bats Program: A System for the Global Acoustic Monitoring of Bats

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    Bats are an important component of mammalian biodiversity and fill such a wide array of ecological niches that they may offer an important multisensory bioindicator role in assessing ecosystem health. There is a need to monitor population trends of bats for their own sake because many populations face numerous environmental threats related to climate change, habitat loss, fragmentation, hunting, and emerging diseases. To be able to establish bat ultrasonic biodiversity trends as a reliable indicator, it is important to standardize monitoring protocols, data management, and analyses. This chapter discusses the main issues to be considered in developing a bat ultrasonic indicator. It focuses on the results from indicator bats program (iBats), a system for the global acoustic monitoring of bats, in Eastern Europe. Finally, the chapter reviews the strengths and weaknesses of the Program and considers the opportunities and threats that it may face in the future

    Expression, purification, crystallization and preliminary X-ray structure analysis of Vibrio cholerae uridine phosphorylase in complex with thymidine

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    A high-resolution structure of the complex of Vibrio cholerae uridine phosphorylase (VchUPh) with its physiological ligand thymidine is important in order to determine the mechanism of the substrate specificity of the enzyme and for the rational design of pharmacological modulators. Here, the expression and purification of VchUPh and the crystallization of its complex with thymidine are reported. Conditions for crystallization were determined with an automated Cartesian Dispensing System using The Classics, MbClass and MbClass II Suites crystallization kits. Crystals of the VchUPh–thymidine complex (of dimensions ∼200–350 µm) were grown by the sitting-drop vapour-diffusion method in ∼7 d at 291 K. The crystallization solution consisted of 1.5 µl VchUPh (15 mg ml(−1)), 1 µl 0.1 M thymidine and 1.5 µl reservoir solution [15%(w/v) PEG 4000, 0.2 M MgCl(2).6H(2)O in 0.1 M Tris–HCl pH 8.5]. The crystals diffracted to 2.12 Å resolution and belonged to space group P2(1) (No. 4), with unit-cell parameters a = 91.80, b = 95.91, c = 91.89 Å, β = 119.96°. The Matthews coefficient was calculated as 2.18 Å(3) Da(−1); the corresponding solvent content was 43.74%

    The European Grassland Butterfly Indicator: 1990–2011

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    This report presents the European Grassland Butterfly Indicator, based on national Butterfly Monitoring Schemes (BMS) in 19 countries across Europe, most of them in the European Union. The indicator shows that since 1990 till 2011 butterfly populations have declined by almost 50 %, indicating a dramatic loss of grassland biodiversity. This also means the situation has not improved since the first version of the indicator published in 2005. Of the 17 species, 8 have declined in Europe, 2 have remained stable and 1 increased. For six species the trend is uncertain. The main driver behind the decline of grassland butterflies is the change in rural land use: agricultural intensification where the land is relatively flat and easy to cultivate, and abandonment in mountains and wet areas, mainly in eastern and southern Europe. Agricultural intensification leads to uniform, almost sterile grasslands for biodiversity. Grassland butterflies thus mainly survive in traditionally farmed low‑input systems (High Nature Value (HNV) Farmland) as well as nature reserves, and on marginal land such as road verges and amenity areas

    The European Butterfly Indicator for Grassland species: 1990-2015

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    This report presents the sixth version of the European Grassland Butterfly Indicator, one of the EU biodiversity indicators of the European Environment Agency.The indicator is based on more than 9200 transects in national Butterfly Monitoring Schemes covering 22 countries across Europe, most of them active in the European Union. In 2015, counts were made in more than 4500 transects.Butterflies represent the largest animal group (insects), highly included in food webs, having a high impact on ecosystem services and stability. This report does not represent only the patrimonial conservation of some species, but indicates the changes in biodiversity on grasslands and discusses underlying causes.Fluctuations in numbers between years are typical features of butterfly populations. The assessment of change istherefore made on an analysis of the underlying trend.Indicators were produced on EU, European (EU plus Norway and Switzerland) and pan-European level (including Ukraine, Russia and Armenia).The underlying analysis of the indicator shows that since 1990, grassland butterfly abundance has declined by 30%.The rate of loss has slowed in the last 5-10 years. Part of this slowing down might be caused by climate warming, as this favours cold-blooded animals like butterflies, thus masking the effects of intensification. In parts of Western Europe butterfly numbers outside nature reserves have come to an absolute minimum, meaning it is unlikely for the indicator to further drop.The priority now is to halt further losses and support recovery. This can only come about with greater protection and more sustainable management of semi-natural grassland
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