4,168 research outputs found

    A Candida-based view of fungal sex and pathogenesis

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    Comparisons of the genomes of multiple Candida species reveals several shared traits associated with pathogenesis, but striking differences in sexual reproduction

    Divalent Metal Binding Properties of the Methionyl Aminopeptidase from \u3cem\u3eEscherichia coli\u3c/em\u3e

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    The metal-binding properties of the methionyl aminopeptidase from Escherichia coli (MetAP) were investigated. Measurements of catalytic activity as a function of added Co(II) and Fe(II) revealed that maximal enzymatic activity is observed after the addition of only 1 equiv of divalent metal ion. Based on these studies, metal binding constants for the first metal binding event were found to be 0.3 ± 0.2 μM and 0.2 ± 0.2 μM for Co(II)- and Fe(II)-substituted MetAP, respectively. Binding of excess metal ions (\u3e50 equiv) resulted in the loss of ∼50% of the catalytic activity. Electronic absorption spectral titration of a 1 mM sample of MetAP with Co(II) provided a binding constant of 2.5 ± 0.5 mM for the second metal binding site. Furthermore, the electronic absorption spectra of Co(II)-loaded MetAP indicated that both metal ions reside in a pentacoordinate geometry. Consistent with the absorption data, electron paramagnetic resonance (EPR) spectra of [CoCo(MetAP)] also indicated that the Co(II) geometries are not highly constrained, suggesting that each Co(II) ion in MetAP resides in a pentacoordinate geometry. EPR studies on [CoCo(MetAP)] also revealed that at pH 7.5 there is no significant spin-coupling between the two Co(II) ions, though a small proportion (∼5%) of the sample exhibited detectable spin−spin interactions at pH values \u3e 9.6. EPR studies on [Fe(III)_(MetAP)] and [Fe(III)Fe(III)(MetAP)] also suggested no spin-coupling between the two metal ions. 1H nuclear magnetic resonance (NMR) spectra of [Co(II)_(MetAP)] in both H2O and D2O buffer indicated that the first metal binding site contains the only active-site histidine residue, His171. Mechanistic implications of the observed binding properties of divalent metal ions to the MetAP from E. coli are discussed

    Fractional boundary value problems: Analysis and numerical methods

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    This is the author's PDF of an article published in Fractional calculus and applied analysis 2011. The original publication is available at www.springerlink.comThis journal article discusses nonlinear boundary value problems.Fundacao para a Ciencia e Tecnologi

    The phenotype of circulating follicular-helper T cells in patients with rheumatoid arthritis defines CD200 as a potential therapeutic target

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    Rheumatoid arthritis (RA) is a systemic autoimmune disease primarily affecting synovial joints in which the development of autoantibodies represents a failure of normal tolerance mechanisms, suggesting a role for follicular helper T cells (TFH) in the genesis of autoimmunity. To determine whether quantitative or qualitative abnormalities in the circulating TFH cell population exist, we analysed by flow cytometry the number and profile of these cells in 35 patients with RA and 15 matched controls. Results were correlated with patient characteristics, including the presence of autoantibodies, disease activity, and treatment with biologic agents. Circulating TFH cells from patients with RA show significantly increased expression of the immunoglobulin superfamily receptor CD200, with highest levels seen in seropositive patients (P=0.0045) and patients treated with anti-TNFα agents (P=0.0008). This occurs in the absence of any change in TFH numbers or overt bias towards Th1, Th2, or Th17 phenotypes. CD200 levels did not correlate with DAS28 scores (P=0.887). Although the number of circulating TFH cells is not altered in the blood of patients with RA, the TFH cells have a distinct phenotype. These differences associate TFH cells with the pathogenesis of RA and support the relevance of the CD200/CD200R signalling pathway as a potential therapeutic target

    Environmental impacts and production effects of subsurface drainage at an intensive apple orchard near Donnybrook, WA

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    This report documents results of research carried out within the Donnybrook area, Western Australia, to determine appropriate management for shallow groundwater system responsible for waterlogging of horticultural crops. On one irrigated and previously waterlogged orchard block an assessment is made of the role that subsurface water control had on fruit production and soil water conditions. The report focuses on environmental aspects

    Goomig Farmlands development Baseline water quality in the lower Keep River

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    In 2008 the Ord Irrigation Expansion Project was approved by the Western Australian Government to develop irrigated agriculture on the Weaber Plain. By mid-2014 construction of almost all of the water supply, drainage, access, monitoring and other infrastructure for the 7400ha Goomig Farmlands development had substantially been completed. An important concern is the effect the Goomig Farmlands development may have on the water quality of the downstream lower Keep River aquatic environment, particularly as it relates to threatened species that inhabit or may inhabit the area. Possible increases in salinity, nutrients, suspended sediment, heavy metals and farm chemicals delivered in run-off are therefore of primary interest

    Surface Water Characteristics of the Weaber Plain and lower Keep River Catchments: data review and preliminary results

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    In 2008, the Ord Irrigation Expansion Project was approved by the Western Australian Government to develop irrigated agriculture on the Weaber Plain. An important concern is the effect the Weaber Plain agricultural development may have on the water quality of the downstream Border Creek and Keep River This report assembles and reviews all available physico-chemical water quality data for the lower Keep River and Border Creek systems and presents data from the initial year of a targeted baseline monitoring program (June 2010 – June 2013)

    Observations of localised effects of the Busselton compensating basins on surface water, groundwater and soil salinity

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    Between 2001 and 2009 the Water Corporation constructed three flood-compensating basins on farmland in the Vasse and Sabina river catchments, upstream of in the city of Busselton. The basins are designed to reduce the risk of flooding in urban areas of Busselton by temporarily storing and then regulating runoff during flood events. This report fulfils the reporting requirements of a contract between the Water Corporation and the Department of Agriculture and Food. Data relating to the local groundwater and surface-water dynamics, salinity, nutrients and pH, plus changes to shallow and deep-soil salinity (from repeat ground-based electromagnetic induction [EM] surveying), was reviewed and analysed

    A whole blood monokine-based reporter assay provides a sensitive and robust measurement of the antigen-specific T cell response

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    <p>Abstract</p> <p>Background</p> <p>The ability to measure T-cell responses to antigens is proving critical in the field of vaccine development and for understanding immunity to pathogens, allergens and self-antigens. Although a variety of technologies exist for this purpose IFNγ-ELISpot assays are widely used because of their sensitivity and simplicity. However, ELISpot assays cannot be performed on whole blood, and require relatively large volumes of blood to yield sufficient numbers of peripheral blood mononuclear cells. To address these deficiencies, we describe an assay that measures antigen-specific T cell responses through changes in monokine gene transcription. The biological amplification of the IFNγ signal generated by this assay provides sensitivity comparable to ELISpot, but with the advantage that responses can be quantified using small volumes of whole blood.</p> <p>Methods</p> <p>Whole blood or peripheral blood mononuclear cells (PBMCs) from healthy controls and immunosuppressed recipients of solid organ transplants were incubated with peptide pools covering viral and control antigens or mitogen for 20 hours. Total RNA was extracted and reverse transcribed before amplification in a TaqMan qPCR reaction using primers and probes specific for MIG (CXCL9), IP-10 (CXCL10) and HPRT. The induction of MIG and IP-10 in response to stimuli was analysed and the results were compared with those obtained by ELISpot.</p> <p>Results</p> <p>Antigen-specific T cell responses can be measured through the induction of MIG or IP-10 gene expression in PBMCs or whole blood with results comparable to those achieved in ELISpot assays. The biological amplification generated by IFNγ-R signaling allows responses to be detected in as little as 25 μL of whole blood and enables the assay to retain sensitivity despite storage of samples for up to 48 hours prior to processing.</p> <p>Conclusions</p> <p>A monokine-based reporter assay provides a sensitive measure of antigen-specific T cell activation. Assays can be performed on small volumes of whole blood and remain accurate despite delays in processing. This assay may be a useful tool for studying T cell responses, particularly when samples are limited in quantity or when storage or transportation is required before processing.</p
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