860 research outputs found

    Structure, metamorphism and geochronology of the High Pieria Mountains, N. Greece

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    Delineation of RAID1, the RACK1 interaction domain located within the unique N-terminal region of the cAMP-specific phosphodiesterase, PDE4D5

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    Background The cyclic AMP specific phosphodiesterase, PDE4D5 interacts with the β-propeller protein RACK1 to form a signaling scaffold complex in cells. Two-hybrid analysis of truncation and mutant constructs of the unique N-terminal region of the cAMP-specific phosphodiesterase, PDE4D5 were used to define a domain conferring interaction with the signaling scaffold protein, RACK1. Results Truncation and mutagenesis approaches showed that the RACK1-interacting domain on PDE4D5 comprised a cluster of residues provided by Asn-22/Pro-23/Trp-24/Asn-26 together with a series of hydrophobic amino acids, namely Leu-29, Val-30, Leu-33, Leu-37 and Leu-38 in a 'Leu-Xaa-Xaa-Xaa-Leu' repeat. This was done by 2-hybrid analyses and then confirmed in biochemical pull down analyses using GST-RACK1 and mutant PDE4D5 forms expressed in COS cells. Mutation of Arg-34, to alanine, in PDE4D5 attenuated its interaction with RACK1 both in 2-hybrid screens and in pull down analyses. A 38-mer peptide, whose sequence reflected residues 12 through 49 of PDE4D5, bound to RACK1 with similar affinity to native PDE4D5 itself (Ka circa 6 nM). Conclusions The RACK1 Interaction Domain on PDE4D5, that we here call RAID1, is proposed to form an amphipathic helical structure that we suggest may interact with the C-terminal β-propeller blades of RACK1 in a manner akin to the interaction of the helical G-γ signal transducing protein with the β-propeller protein, G-β

    In Vivo Metal Substitutions in Metal Sequestering Subcellular Compartments: X-Ray Mapping in Cryosections

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    Qualitative digital X-ray mapping techniques were employed to determine the distributions of essential and non-essential elements in three invertebrate models : (1) Pb, Zn, Cd, Cu, Fe in thin cryosections of the hepatopancreas of the terrestrial isopod, Oniscus asellus; (2) Pb, Zn, Cd, Ca in thin cryosections of the chloragogenous tissue of the earthworm, Lumbricus rubellus; and (3) As in air-dried smears and thin cryosections of chloragogen in L. rubellus. Four general conclusions were drawn from the results of these studies: (a) non-essential elements can accumulate, distribute and be compartmentalized because they, or the organo-complexes that they form, act as mimics of essential elements with which they share to a greater or lesser extent certain chemical affinities; (b) thermodynamic considerations notwithstanding, the influence of biological factors on the sequestration and fates of certain elements (e.g., arsenic) is profound through modifications of redox states and organo-compound formation; (c) X-ray mapping, combined with anhydrous preparative procedures, yields unbiased information concerning the relative spatial distributions of several elements in structurally heterogeneous sampling fields , although the morphological characterization of (occasionally unsuspected) subcellular compartments may be constrained by the intrinsic quality of the preparation; and (d) X-ray microanalysis yields codistribution data, when integrated with biochemical information from other sources, which give strong pointers to the identity of binding ligands and of the valence state of sequestered cations

    Locked out? Navigating the geographies of precarity on Britain's waterways

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    AbstractMotivations for living on the UK's waterways range from lifestyle to financial, but increasing numbers have been pushed aboard in response to current, and longstanding, cost‐of‐living and housing crises. However, while more affordable than living on land, our qualitative investigation reveals a diversity of practices and experiences of marginalisation on the waterways, drawing out the impacts of temporal and spatial fluidity to inform our understanding of precarity in a mobile world. The waterways are a contested and politicised space with diverse actors seeking to delineate legitimate practices and users. Liveaboard boaters practice residential subjectivities in what others designate as leisure spaces. Resistance to such powerful claims to the waterways is not necessarily chosen or active and yet has become implicit to boaters' everyday practices. The mobility and liminality offered by boat living, experienced by some as a chosen freedom and others as a restrictive imposition, presents opportunities for resistance to powerful interests but also social marginalisation and stigmatisation. Through a focus on moorings, we highlight the legal and spatial grey areas regularly inhabited by all boaters. In seemingly secure marinas, we expose a hidden world of housing precarity with residential boaters' living in the shadows of these leisure‐designed spaces, resulting in no stability, security or statutory rights. For boaters out on the waterways, precarity continued, albeit with different manifestations. Powerful local actors mobilise narratives that disembed boaters from the waterways through the absence and poor maintenance of essential facilities alongside the loss of legal, safe mooring sites. Precarity emerges as not something restricted to ‘vulnerable groups’ but an ever present ontological condition. As such it is critical to understand how individuals and communities are responding to their implicit vulnerability, and the opportunities and challenges that mobility offers to the development and practice of this agency.</jats:p

    Healthcare access for refugees in Greece: Challenges and opportunities

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    The arrival of more than one million refugees and migrants in Europe in 2015, most of whom transited through Greece, has placed significant strains on local health systems and demonstrated the need for preparedness to meet the immediate and longer-term health needs of arrivals in EU countries. Population movements will continue to occur and the need for cost effective, appropriate provision of both primary and secondary health services to meet these needs is key. The Global Compact on Migration was ratified in 2018 and forms an overarching, international agreement to address safe, orderly and regular migration which benefits refugees and migrants as well as host communities; however, it did not give due emphasis to health. In this manuscript, we explore the evolution of the health response for refugees in Greece over the last three years, the challenges faced at different times of the response and the efforts to integrate refugees into Greece’s health system

    Group A streptococcal vaccine delivery by immunization with a self-adjuvanting M protein-based lipid core peptide construct

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    Background & objectives: To develop a broad strain coverage GAS vaccine, several strategies have been investigated which included multi-epitope approaches as well as targeting the M protein conserved C-region. These approaches, however, have relied on the use of adjuvants that are toxic for human application. The development of safe and effective adjuvants for human use is a key issue in the development of effective vaccines. In this study, we investigated the lipid polylysine core peptide (LCP) system as a self-adjuvanting GAS vaccine delivery approach. Methods: An LCP-GAS construct was synthesised incorporating multiple copies of a protective peptide epitope (J8) from the conserved carboxy terminal C-repeat region of the M protein. B10.BR mice were immunized parenterally with the LCP-J8 construct, with or without conventional adjuvant, prior to the assessment of immunogenicity and the induction of serum opsonic antibodies. Results: Our data demonstrated immunogenicity of LCP-J8 when coadministered in complete Freund's adjuvant (CFA), or administered in the absence of conventional adjuvant. In both cases, immunization led to the induction of high-titre J8 peptide-specific serum IgG antibody responses, and the induction of heterologous opsonic antibodies that did not cross-react with human heart tissue proteins. Interpretation & conclusion: These data indicated the potential of a novel self-adjuvanting LCP vaccine delivery system incorporating a synthetic GAS M protein C-region peptide immunogen in the induction of broadly protective immune responses, and pointed to the potential application of this system in human vaccine development against infectious diseases

    Shifts in soil microbial community structure, nitrogen cycling and the concomitant declining N availability in ageing primary boreal forest ecosystems

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    AbstractPlant growth in boreal forests is commonly limited by a low supply of nitrogen, a condition that may be aggravated by high tree below-ground allocation of carbon to ectomycorrhizal (ECM) fungi and associated microorganisms. These in turn immobilise N and reduce its availability to plants as boreal ecosystems develop. Here, we studied a boreal forest ecosystem chronosequence created by new land rising out of the sea due to iso-static rebound along the coast of northern Sweden. We used height over the ocean to estimate ecosystem age and examined its relationship to soil microbial community structure and the gross turnover of N. The youngest soils develop with meadows by the coast, followed by a zone of N2-fixing alder trees, and primary boreal conifer forest on ground up to 560 years old. The young soils in meadows contained little organic matter and microbial biomass per unit area. Nitrogen was turned over at low rates when expressed per area (m−2), but specific rates (per gram soil carbon (C)) were the highest found along the transect. In the zone with alder, the amounts of soil C and microbial biomass were much higher (bacterial biomass had doubled and fungal biomass quadrupled). Rates of gross N mineralisation (expressed on an area basis) were highest, but the retention of added labelled NH4+ was lowest in this soil as compared to other ages. The alder zone also had the largest extractable pools of inorganic N in soil and highest N % in plant foliage. In the older conifer forest ecosystems the amounts of soil C and N, as well as biomass of both bacteria and fungi increased. Data on organic matter 14C suggested that the largest input of recently fixed plant C occurred in the younger coniferous forest ecosystems. With increasing ecosystem age, the ratio of microbial C to total soil C was constant, whereas the ratio of microbial N to total soil N increased and gross N mineralization declined. Simultaneously, plant foliar N % decreased and the natural abundance of 15N in the soil increased. More specifically, the difference in δ15N between plant foliage and soil increased, which is related to relatively greater retention of 15N relative to 14N by ECM fungi as N is taken up from the soil and some N is transferred to the plant host. In the conifer forest, where these changes were greatest, we found increased fungal biomass in the F- and H-horizons of the mor-layer, in which ECM fungi are known to dominate (the uppermost horizon with litter and moss is dominated by saprotrophic fungi). Hence, we propose that the decreasing availability of N to the plants and the subsequent decline in plant production in ageing boreal forests is linked to high tree belowground C allocation to ECM fungi, a strong microbial sink for available soil N

    Bulk mineralogical characterisation of oilfield reservoir rocks and sandstones using DRIFTS and partial least squares analysis

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    The feasibility of applying Partial Least Squares (PLS) to the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) spectra of mineral mixtures, quarry sandstones and oilfield reservoir rocks has been investigated and shown considerable potential for accurate and precise mineralogical analysis. Rapid spectrum acquisition and data processing together with small sample size requirements are key advantages of the PLS–DRIFTS method. A PLS model was created from the DRIFTS spectra of mixtures of seven mineral standards chosen to represent the most frequently encountered minerals in sandstone-type rocks; quartz, dolomite, montmorillonite, illite, kaolinite, chlorite and albite. The PLS–DRIFTS model was able to quantify the mineral components of independent mixtures with an absolute error of 1 wt.% for all the minerals (concentration range 0–30 wt.%) with the exception of quartz which exhibited an absolute error of 3 wt.% (concentration range 50–90 wt.%). The results provided by applying this PLS–DRIFTS model to several sandstone-type quarry rocks and a suite of oilfield reservoir rocks were considerably better than anticipated even though the model did not describe all the mineral components present in the samples nor the entire variance of constituent mineral components (e.g. crystallinity). The model was not able to differentiate between montmorillonite and illite probably due to the similarity of the DRIFTS spectra of these minerals, but it was able to quantify the combined (montmorillonite + illite) concentrations to within 1 wt.%. The model over-predicted the concentration of albite in the quarry rocks due to the presence of K-feldspar, which has a similar DRIFTS spectrum and was not included in the model. However, the model accurately predicted the total (albite and K-feldspar) concentration to within 4 wt.%. A separate PLS–DRIFTS model constructed using the DRIFTS spectra of the oilfield reservoir rocks showed that the carbonate components, calcite and dolomite could be differentiated and quantified to within 5.0 and 3.6 wt.%, respectively. This feasibility study confirmed the strong potential of combining DRIFTS with a multivariate statistical approach such as PLS and it is clear that more sophisticated models, that incorporates and describes a higher percentage of the variance in unknowns, would further improve the predictions

    Determinants of tenancy sustainment following homelessness: A Systematic Review

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    Background: Tenancy sustainment—the maintenance of a tenancy to avoid a premature end of tenure—is fundamental to homelessness prevention. Understanding what enables a successful tenancy is essential to inform interventions to support people leave homelessness. Objective: To conduct a systematic review to identify determinants associated with tenancy sustainment following homelessness. Search methods: A detailed search of 12 electronic databases, as well as grey literature sources, was conducted in 2015 and updated in 2016. The study protocol is registered with PROSPERO (CRD42015019361). Selection criteria: All study designs with a population of homeless or formerly homeless individuals, in which tenancy sustainment was the primary outcome were included. Abstract and full text review was carried out independently by two reviewers. The methodological quality of articles was assessed using QualSyst, a validated quality appraisal tool. Data collection and analysis: A data extraction form was developed for the review and was completed by two reviewers to ensure accuracy. The heterogeneity of included studies indicated that a narrative overview of the results was most appropriate. Main results: Forty three articles reporting 38 studies were included. The determinants were categorized at four levels: individual, interpersonal, community and structural. Participation in specific programs, for example Housing First, receiving social support and being older were identified as the possible determinants of tenancy sustainment. Author’s conclusions: This systematic review is the first, to our knowledge, to focus solely on tenancy sustainment as a primary outcome. A range of determinants associated with tenancy sustainment was identified but it was difficult to draw strong conclusions due to the heterogeneity of the studies. Despite being a fundamental concept in homelessness research, tenancy sustainment is poorly defined and conceptualised. A deeper understanding of tenancy sustainment will inform the development and evaluation of interventions that support people to leave homelessness and maintain tenancies. Public health implications: Housing stability is central to preventing homelessness and addressing the numerous public health concerns that can co-occur with homelessness. Our review highlights that a standardized approach to measuring housing stability and more high quality intervention studies are essential in future research

    The Lore of Low Methane Livestock:Co-Producing Technology and Animals for Reduced Climate Change Impact

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    Methane emissions from sheep and cattle production have gained increasing profile in the context of climate change. Policy and scientific research communities have suggested a number of technological approaches to mitigate these emissions. This paper uses the concept of co-production as an analytical framework to understand farmers’ evaluation of a 'good animal’. It examines how technology and sheep and beef cattle are co-produced in the context of concerns about the climate change impact of methane. Drawing on 42 semi-structured interviews, this paper demonstrates that methane emissions are viewed as a natural and integral part of sheep and beef cattle by farmers, rather than as a pollutant. Sheep and beef cattle farmers in the UK are found to be an extremely heterogeneous group that need to be understood in their specific social, environmental and consumer contexts. Some are more amenable to appropriating methane reducing measures than others, but largely because animals are already co-constructed from the natural and the technical for reasons of increased production efficiency
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