221 research outputs found

    Phosphatidylinositol-(4,5)-bisphosphate regulates sorting signal recognition by the clathrin-associated adaptor complex AP2

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    The alpha,beta2,mu2,sigma2 heterotetrameric AP2 complex is recruited exclusively to the phosphatidylinositol-4,5-bisphosphate (PtdIns4,5P(2))-rich plasma membrane where, amongst other roles, it selects motif-containing cargo proteins for incorporation into clathrin-coated vesicles. Unphosphorylated and mu2Thr156-monophosphorylated AP2 mutated in their alphaPtdIns4,5P(2), mu2PtdIns4,5P(2), and mu2Yxxvarphi binding sites were produced, and their interactions with membranes of different phospholipid and cargo composition were measured by surface plasmon resonance. We demonstrate that recognition of Yxxvarphi and acidic dileucine motifs is dependent on corecognition with PtdIns4,5P(2), explaining the selective recruitment of AP2 to the plasma membrane. The interaction of AP2 with PtdIns4,5P(2)/Yxxvarphi-containing membranes is two step: initial recruitment via the alphaPtdIns4,5P(2) site and then stabilization through the binding of mu2Yxxvarphi and mu2PtdIns4,5P(2) sites to their ligands. The second step is facilitated by a conformational change favored by mu2Thr156 phosphorylation. The binding of AP2 to acidic-dileucine motifs occurs at a different site from Yxxvarphi binding and is not enhanced by mu2Thr156 phosphorylation

    Nutritional Skewing of Conceptus Sex in Sheep: Effects of a Maternal Diet Enriched in Rumen-Protected Polyunsaturated Fatty acids (PUFA)

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    doi:10.1186/1477-7827-6-21Evolutionary theory suggests that in polygynous mammalian species females in better body condition should produce more sons than daughters. Few controlled studies have however tested this hypothesis and controversy exists as to whether body condition score or maternal diet is in fact the determining factor of offspring sex. Here, we examined whether maternal diet, specifically increased n-6 polyunsaturated fatty acid(PUFA) intake, of ewes with a constant body condition score around the time of conception influenced sex ratio.The research was supported by USDA/CSREES/NRI Grant 2001-35203- 10693 (to RMR) and a Life Sciences Molecular Biology Fellowship, University of Missouri (partial salary support for MPG)

    Downwearing rates on shore platforms of different calcareous lithotypes

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    Vertical lowering (downwearing) of shore platform surfaces is a very important mechanism in their morphological evolution albeit much remains incompletely understood. The efficacy of mechanical and chemical weathering acting on a given substrate, together with erosional processes, influences downwearing rates. In order to determine the relationship between lithotypes and downwearing rates, data collected from a Transverse Micro-erosion Meter were obtained for shore platforms of three different calcareous lithotypes (biocalcarenite, calcarenite and carbonated siltstone) along the central Algarve coast (Southern Portugal). Downwearing rates ranged between 0.096 mm year−1 and 1.676 mm year−1 in biocalcarenite and weakly cemented calcarenite, respectively. In addition, physical properties of the rocks comprising the platforms were measured, including uniaxial compressive strength (as determined by the Point Load Test), porosity, and calcium carbonate content. The results show that downwearing depends primarily on the intrinsic properties of the substrate. Porosity, in particular, acts in two ways: (i) it tends to weaken the substrate; and, (ii) it controls the downward extent of the water percolation and therefore the depth of the weathering mantle subject to erosion by waves and currents.Portuguese Foundation for Science and Technology (FCT) through Research Projects PTDC/CTEGEX/70448/2006 (BISHOP) and PTDC/CTE-GIX/111230/2009 (EROS)

    An evaluation of an online STI service across London: reviewing uptake, utility and outcomes over a 4-year period

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    OBJECTIVES: Since 2018, Sexual Health London (SHL) has provided remote sexually transmitted infection (STI) testing services to London residents over 16 years of age. SHL was an asymptomatic screening service. In 2020, SHL widened access to non-urgent symptomatic testing. We undertook a 4-year evaluation on the uptake of SHL’s online testing pathway and outcomes, including the association of positive chlamydia and gonorrhoea nucleic acid amplification test (NAAT) outcomes with user demographics and user utility. METHODS: This is a retrospective data analysis of routine SHL clinical data from 8 January 2018 to 31 March 2022 of all STI test kit orders, focusing on HIV, chlamydia and gonorrhoea outcomes. Descriptive analysis on uptake of each stage of SHL’s clinical care pathway is provided, including HIV testing outcomes. Binary logistic regression was used to examine the association between SHL user-completed online consultation information, SHL uptake and chlamydia and gonorrhoea NAAT results (negative or positive). RESULTS: During the evaluation period, there were 1 476 187 orders made by 670 293 unique users. The return rate for chlamydia and gonorrhoea NAATs was 79.5% and 67.6% for HIV blood samples. The positivity rate from sufficient samples was 4.5% for chlamydia, 1.6% for gonorrhoea and 0.3% reactivity for HIV. There were increased odds of a positive chlamydia and gonorrhoea NAAT result in non-cisgender women, those with a high number of STI orders, non-UK born and those who collected an STI test kit from a clinic-based service. CONCLUSIONS: To date, this is the largest number of orders in an evaluation of online postal sexual health infection testing in the UK, and highest return rate of samples, suggesting acceptability of SHL for STI testing. Positivity rates for chlamydia and gonorrhoea NAAT tests are lower than national figures, which may reflect asymptomatic screening prior to 2020 and testing of non-urgent symptoms since 2020

    A Proposed Rule-Discovery Scheme for Regionalisation of Rainfall-Runoff Characteristics in New South Wales, Australia

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    A project which sets out to explore alternative methods of regionalisation for prediction ofstreamflow in ungauged catchments is described. A commonly applied regionalisation methodology estimatesmodel parameters for the ungauged basin from multiple linear regressions between parameters and catchmentattributes, calibrated on gauged catchments. Its effectiveness is limited by the availability of sufficientlysimilar, well gauged and modelled catchments. In this paper a different approach is adopted, employing a datamining methodology to seek a useful set of rules in the catchment attribute space with parameter values asconsequent. The outline of a hypothesis testing algorithm is given, along with a suggestion for a newdiscretisation method. The techniques are both based on the information theoretic concepts of cross entropyand mutual information

    Markers of low level arsenic exposure for evaluating human cancer risks in a US population

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155831/1/Karagas_et_al_2001_Markers_of_low_level.pd

    Data Mining as a Tool for Environmental Scientists

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    Over recent years a huge library of data mining algorithms has been developed to tackle a variety of problems in fields such as medical imaging and network traffic analysis. Many of these techniques are far more flexible than more classical modelling approaches and could be usefully applied to data-rich environmental problems. Certain techniques such as Artificial Neural Networks, Clustering, Case-Based Reasoning and more recently Bayesian Decision Networks have found application in environmental modelling while other methods, for example classification and association rule extraction, have not yet been taken up on any wide scale. We propose that these and other data mining techniques could be usefully applied to difficult problems in the field. This paper introduces several data mining concepts and briefly discusses their application to environmental modelling, where data may be sparse, incomplete, or heterogenous

    Engineering protein processing of the mammary gland to produce abundant hemophilia B therapy in milk

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    Both the low animal cell density of bioreactors and their ability to post-translationally process recombinant factor IX (rFIX) limit hemophilia B therapy to transgenic pigs to make rFIX in milk at about 3,000-fold higher output than provided by industrial bioreactors. However, this resulted in incomplete γ-carboxylation and propeptide cleavage where both processes are transmembrane mediated. We then bioengineered the co-expression of truncated, soluble human furin (rFurin) with pro-rFIX at a favorable enzyme to substrate ratio. This resulted in the complete conversion of pro-rFIX to rFIX while yielding a normal lactation. Importantly, these high levels of propeptide processing by soluble rFurin did not preempt γ-carboxylation in the ER and therefore was compartmentalized to the Trans-Golgi Network (TGN) and also to milk. The Golgi specific engineering demonstrated here segues the ER targeted enhancement of γ-carboxylation needed to biomanufacture coagulation proteins like rFIX using transgenic livestock

    Locomotion and muscle mass measures in a murine model of collagen-induced arthritis

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    Background: Rheumatoid arthritis (RA) is characterized by chronic poly-arthritis, synovial hyperplasia, erosive synovitis, progressive cartilage and bone destruction accompanied by a loss of body cell mass. This loss of cell mass, known as rheumatoid cachexia, predominates in the skeletal muscle and can in part be explained by a decreased physical activity. The murine collagen induced arthritis (CIA) model has been proven to be a useful model in RA research since it shares many immunological and pathological features with human RA. The present study explored the interactions between arthritis development, locomotion and muscle mass in the CIA model. Methods: CIA was induced in male DBA/1 mice. Locomotion was registered at different time points by a camera and evaluated by a computerized tracing system. Arthritis severity was detected by the traditionally used semi-quantitative clinical scores. The muscle mass of the hind-legs was detected at the end of the study by weighing. A methotrexate (MTX) intervention group was included to study the applicability of the locomotion and muscle mass for testing effectiveness of interventions in more detail. Results: There is a strong correlation between clinical arthritis and locomotion. The correlations between muscle mass and locomotion or clinical arthritis were less pronounced. MTX intervention resulted in an improvement of disease severity accompanied by an increase in locomotion and muscle mass. Conclusion: The present data demonstrate that registration of locomotion followed by a computerized evaluation of the movements is a simple non invasive quantitative method to define disease severity and evaluate effectiveness of therapeutic agents in the CIA model.

    Engineering protein processing of the mammary gland to produce abundant hemophilia B therapy in milk

    Get PDF
    Both the low animal cell density of bioreactors and their ability to post-translationally process recombinant factor IX (rFIX) limit hemophilia B therapy to transgenic pigs to make rFIX in milk at about 3,000-fold higher output than provided by industrial bioreactors. However, this resulted in incomplete γ-carboxylation and propeptide cleavage where both processes are transmembrane mediated. We then bioengineered the co-expression of truncated, soluble human furin (rFurin) with pro-rFIX at a favorable enzyme to substrate ratio. This resulted in the complete conversion of pro-rFIX to rFIX while yielding a normal lactation. Importantly, these high levels of propeptide processing by soluble rFurin did not preempt γ-carboxylation in the ER and therefore was compartmentalized to the Trans-Golgi Network (TGN) and also to milk. The Golgi specific engineering demonstrated here segues the ER targeted enhancement of γ-carboxylation needed to biomanufacture coagulation proteins like rFIX using transgenic livestock
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