433 research outputs found

    Inositol 1,3,4,5,6-pentakisphosphate 2-kinase is a distant IPK member with a singular inositide binding site for axial 2-OH recognition

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    Inositol phosphates (InsPs) are signaling molecules with multiple roles in cells. In particular Graphic (InsP6) is involved in mRNA export and editing or chromatin remodeling among other events. InsP6 accumulates as mixed salts (phytate) in storage tissues of plants and plays a key role in their physiology. Human diets that are exclusively grain-based provide an excess of InsP6 that, through chelation of metal ions, may have a detrimental effect on human health. Ins(1,3,4,5,6)P5 2-kinase (InsP5 2-kinase or Ipk1) catalyses the synthesis of InsP6 from InsP5 and ATP, and is the only enzyme that transfers a phosphate group to the axial 2-OH of the myo-inositide. We present the first structure for an InsP5 2-kinase in complex with both substrates and products. This enzyme presents a singular structural region for inositide binding that encompasses almost half of the protein. The key residues in substrate binding are identified, with Asp368 being responsible for recognition of the axial 2-OH. This study sheds light on the unique molecular mechanism for the synthesis of the precursor of inositol pyrophosphates

    Footsteps across time : the evolution, use and relevance of battlefield visits to the British Armed Forces

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    This study examines the educational use made by military forces around the world, but primarily those of the United Kingdom, of visits to past battlefields. Investigation suggests this practice commenced formally in Prussia and may be nearing its 200th anniversary; certainly the British Army’s Staff College at Camberley has been visiting battlefields for educational purposes since at least 1885. To date, no extended academic study of this practice has been undertaken, and no specific use of the Staff College Battlefield Tour Archive has been made in this context. An examination is made of educational theory, by which the effectiveness and value of battlefield visiting can be measured. This study creates a typology of battlefield visiting, and thus acknowledges a much older civilian tradition of making pilgrimages to past scenes of conflict (initially to pray for the souls of the dead), which later evolved into civilian battlefield tourism to destinations such as Waterloo and Gettysburg. The work examines the nature of British battlefield visiting, using the Staff College Battlefield Tour Archive, in four phases: before the First World War; during the inter-war period; during the post-Second World War and Cold War periods, and at the time of writing. Throughout the study, parallels are drawn with military battlefield visits undertaken by the American and German armed forces. The conclusion is made that battlefield visiting is a unique and valuable tool in military education that is not well managed, and that no recognition is given to its value in terms of classic education theory.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    A Plug-and-Play Approach for the De Novo Generation of Dually Functionalized Bispecifics

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    Diseases are multifactorial, with redundancies and synergies between various pathways. However, most of the antibody-based therapeutics on the market interact with only one target, thus limiting their efficacy. The targeting of multiple epitopes could improve the therapeutic index of treatment and counteract mechanisms of resistance. To this effect, a new class of therapeutics has emerged: bispecific antibodies. Bispecific formation using chemical methods is rare and low-yielding and/or requires a large excess of one of the two proteins to avoid homodimerization and heterogeneity. In order for chemically prepared bispecifics to deliver their full potential, high-yielding, modular, and reliable cross-linking technologies are required. Herein, we describe a novel approach not only for the rapid and high-yielding chemical generation of bispecific antibodies from native antibody fragments, but also for the site-specific dual functionalization of the resulting bioconjugates. Based on orthogonal clickable functional groups, this strategy enables the assembly of functionalized bispecifics with controlled loading in a modular and convergent manner

    Sulphur and carbon cycling in the subduction zone mélange

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    Subduction zones impose an important control on the geochemical cycling between the surficial and internal reservoirs of the Earth. Sulphur and carbon are transferred into Earth’s mantle by subduction of pelagic sediments and altered oceanic lithosphere. Release of oxidizing sulphate- and carbonate-bearing fluids modifies the redox state of the mantle and the chemical budget of subduction zones. Yet, the mechanisms of sulphur and carbon cycling within subduction zones are still unclear, in part because data are typically derived from arc volcanoes where fluid compositions are modified during transport through the mantle wedge. We determined the bulk rock elemental, and sulphur and carbon isotope compositions of exhumed ultramafic and metabasic rocks from Syros, Greece. Comparison of isotopic data with major and trace element compositions indicates seawater alteration and chemical exchange with sediment-derived fluids within the subduction zone channel. We show that small bodies of detached slab material are subject to metasomatic processes during exhumation, in contrast to large sequences of obducted ophiolitic sections that retain their seafloor alteration signatures. In particular, fluids circulating along the plate interface can cause sulphur mobilization during several stages of exhumation within high-pressure rocks. This takes place more pervasively in serpentinites compared to mafic rocks

    TGFβ upregulates PAR-1 expression and signalling responses in A549 lung adenocarcinoma cells

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    The major high-affinity thrombin receptor, proteinase activated receptor-1 (PAR-1) is expressed at low levels by the normal epithelium but is upregulated in many types of cancer, including lung cancer. The thrombin-PAR-1 signalling axis contributes to the activation of latent TGFβ in response to tissue injury via an avβ6 integrin-mediated mechanism. TGFβ is a pleiotropic cytokine that acts as a tumour suppressor in normal and dysplastic cells but switches into a tumour promoter in advanced tumours. In this study we demonstrate that TGFβ is a positive regulator of PAR-1 expression in A549 lung adenocarcinoma cells, which in turn increases the sensitivity of these cells to thrombin signalling. We further demonstrate that this effect is Smad3-, ERK1/2-and Sp1-dependent. We also show that TGFβ-mediated PAR-1 upregulation is accompanied by increased expression of integrin av and β6 subunits. Finally, TGFβ pre-stimulation promotes increased migratory potential of A549 to thrombin. These data have important implications for our understanding of the interplay between coagulation and TGFβ signalling responses in lung cancer

    Targeting cancer cells with folic acid-iminoboronate fluorescent conjugates.

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    Herein we present the synthesis of fluorescent 2-acetylbenzeneboronic acids that undergo B-N promoted conjugation with lysozyme and N-(2-aminoethyl) folic acid (EDA-FA), generating conjugates that are selectively recognized and internalized by cancer cells that over-express folic acid receptors

    Measuring the complexity of general practice consultations:development and validation of a complexity measure

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    Background: The complexity of general practice consultations may be increasing and varies in different settings. A measure of complexity is required to test these hypotheses. Aim: To develop a valid measure of general practice consultation complexity applicable to routine medical records. Design and setting: Delphi study to select potential indicators of complexity followed by a cross-sectional study in English general practices to develop and validate a complexity measure. Method: The online Delphi study over two rounds identified potential indicators of consultation complexity. The cross-sectional study used an age–sex stratified random sample of patients and general practice face-to-face consultations from 2013/2014 in the Clinical Practice Research Datalink. The authors explored independent relationships between each indicator and consultation duration using mixed-effects regression models, and revalidated findings using data from 2017/2018. The proportion of complex consultations in different age–sex groups was assessed. Results: A total of 32 GPs participated in the Delphi study. The Delphi panel endorsed 34 of 45 possible complexity indicators after two rounds. After excluding factors because of low prevalence or confounding, 17 indicators were retained in the cross-sectional study. The study used data from 173 130 patients and 725 616 face-to-face GP consultations. On defining complexity as the presence of any of these 17 factors, 308 370 consultations (42.5%) were found to be complex. Mean duration of complex consultations was 10.49 minutes, compared to 9.64 minutes for non-complex consultations. The proportion of complex consultations was similar in males and females but increased with age. Conclusion: The present consultation complexity measure has face and construct validity. It may be useful for research, management and policy, and for informing decisions about the range of resources needed in different practices

    Highly homogeneous antibody modification through optimisation of the synthesis and conjugation of functionalised dibromopyridazinediones

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    Due to their exquisite cysteine-selectivity, excellent stability, and ability to functionally rebridge disulfide bonds, dibromopyridazinediones are emerging as an exciting new class of bioconjugation reagents, particularly in the field of antibody conjugation. Despite this, relatively little work has been performed on the optimisation of their synthesis and subsequent reaction with immunoglobulins. Herein we present a novel synthetic route towards functionalised dibromopyridazinediones, proceeding via an isolatable dibromopyridazinedione-NHS ester. Reaction of this activated intermediate with a variety of amines produces functional dibromopyridazinediones in good to excellent yields. The disulfide rebridging capacity of these reagents was optimised on the clinically relevant IgG1 trastuzumab, resulting in a general method which allows for the generation of site-selectively modified native trastuzumab with over 90% homogeneity (no disulfide scrambling) without the need for protein engineering or enzymatic conjugation

    Analytical Pluralism in Qualitative Research: A Meta-Study

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    Recent interest in analytical pluralism – the application of more than one qualitative analytical method to a single data set – has demonstrated its potential to produce multiple, complex and varied understandings of phenomena. However tensions remain regarding the commensurability of findings produced from diverse theoretical frameworks, the practical application of multiple methods of analysis and the capacity of pluralism to contribute to knowledge in psychology. This study addresses these issues, through a critical interpretation of existing qualitative studies that utilised analytical pluralism. Using a meta-study design, we examined the use of theory, application of methods and production of findings in studies that had adopted qualitative analytical pluralism. Following comprehensive database searches, 10 articles were included in the analysis. Epistemological and ontological considerations, the influence of decisions made in the practical application of pluralism and approaches to interpreting findings produced from multiple analyses are discussed, and implications for future research are considered
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