174 research outputs found

    A SARS-CoV-2 spike binding DNA aptamer that inhibits pseudovirus infection by an RBD-independent mechanism

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    The receptor binding domain (RBD) of the spike glycoprotein of the coronavirus SARS‐CoV‐2 (CoV2‐S) binds to the human angiotensin converting enzyme 2 (ACE2) representing the initial contact point for leveraging the infection cascade. We used an automated selection process and identified an aptamer that specifically interacts with CoV2‐S. The aptamer does not bind to the RBD of CoV2‐S and does not block the interaction of CoV2‐S with ACE2. Notwithstanding, infection studies revealed potent and specific inhibition of pseudoviral infection by the aptamer. The present study opens up new vistas in developing SARS‐CoV2 infection inhibitors, independent of blocking the ACE2 interaction of the virus and harnesses aptamers as potential drug candidates and tools to disentangle hitherto inaccessible infection modalities, which is of particular interest in light of the increasing number of escape mutants that are currently being reported

    Spoilt for Choice: Explaining the location choice of Turkish Transnationals

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    The investments of Turkish entrepreneurs to other countries increased in the 1990s. This paper explores Turkish FDI abroad focusing on the factors influencing the FDI decision and location choice, using micro data collected from investor firms. A micro level data set for the Turkish FDI abroad is constructed using the information gathered through questionnaires conducted at some selected firms, which have engaged in FDI abroad. The data is explored using statistical and econometric techniques by grouping the countries based on their geographical location. Among the factors that determine the location choice of investors access to consumers and suppliers, market penetration; the presence of Turkish firms and Turkish population, and similarity to Turkey; trade opportunities and preferential trade agreements; together with labour costs and availability of skilled workers affect the location choice of Turkish transnationals. Key words: outward foreign direct investment, location choice, Turke

    What causes the regional disparity of FDI in Russia? a spatial analysis

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    We analyse the determinants of the regional disparity of FDI inflows to Russia. The spatial distribution of FDI is attributed to regional and/or trans-regional factors. Region specific characteristics such as wage, education level, transportation as well as gross regional product, which accounts for market size, in host and alternative regions are considered to analyze the spatial interaction between regions employing spatial econometrics. We find that shocks to FDI levels in proximate regions have no effect on FDI inflows to hosts. However, FDI in a region depends on spatial market size and endowment of natural resources in alternative host regions

    Spoilt for Choice: Explaining the location choice of Turkish Transnationals

    Get PDF
    The investments of Turkish entrepreneurs to other countries increased in the 1990s. This paper explores Turkish FDI abroad focusing on the factors influencing the FDI decision and location choice, using micro data collected from investor firms. A micro level data set for the Turkish FDI abroad is constructed using the information gathered through questionnaires conducted at some selected firms, which have engaged in FDI abroad. The data is explored using statistical and econometric techniques by grouping the countries based on their geographical location. Among the factors that determine the location choice of investors access to consumers and suppliers, market penetration; the presence of Turkish firms and Turkish population, and similarity to Turkey; trade opportunities and preferential trade agreements; together with labour costs and availability of skilled workers affect the location choice of Turkish transnationals. Key words: outward foreign direct investment, location choice, Turke

    The haematopoietic GTPase RhoH modulates IL3 signalling through regulation of STAT activity and IL3 receptor expression

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    <p>Abstract</p> <p>Background</p> <p>RhoH is a constitutively active member of the family of Rho GTPases. Its expression is restricted to the haematopoietic lineage, where it serves as a positive regulator for T cell selection and mast cell function and as a negative regulator for growth-related functions in other lineages. Here, we examined the activation of signal transducer and activator of transcription (STAT) proteins in response to stimulation with interleukin 3 (IL3).</p> <p>Results</p> <p>Using the murine IL3-dependent cell line BaF3 we investigated the influence of RhoH protein expression levels on IL3-mediated cellular responses. RhoH overexpressing cells showed lower sensitivity to IL3 and decreased STAT5 activation. SiRNA-mediated repression of <it>RhoH </it>gene expression led to an increase in proliferation and STAT5 activity which correlated with an increased number of IL3 receptor α chain molecules, also known as CD123, expressed at the cell surface. Interestingly, these findings could be reproduced using human THP-1 cells as a model system for acute myeloid leukaemia, where low RhoH levels are known to be an unfavourable prognostic marker. Overexpression of RhoH on the other hand caused an induction of STAT1 activity and western blot analysis revealed that activated STAT1 is phosphorylated on Tyr701. STAT1 is known to induce apoptosis or cell cycle arrest and we detected an upregulation of cyclin-dependent kinase inhibitors (CDKI) <it>p21<sup>Cip1 </sup></it>and <it>p27<sup>Kip1 </sup></it>in RhoH overexpressing BaF3 cells.</p> <p>Conclusions</p> <p>We propose that RhoH functions as a negative regulator for IL3-induced signals through modulation of the JAK-STAT pathway. High levels of RhoH allow the IL3-dependent activation of STAT1 causing decreased proliferation through upregulation of <it>p21<sup>Cip1 </sup></it>and <it>p27<sup>Kip1</sup></it>. Low RhoH levels on the other hand led to an upregulation of IL3-dependent cell growth, STAT5 activity and an increase of CD123 surface expression, linking RhoH to a CD123/STAT5 phenotype that has been described in AML patients.</p

    Electricity Futures Prices

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    This paper provides insight in the time-varying relation between electricity futures prices and fundamentals in the form of prices of contracts for fossil fuels. As supply curves are not constant and different producers have different marginal costs of production, we argue that the relation between electricity futures prices and futures prices of underlying fundamentals such as natural gas, coal and emission rights are not constant and vary over time. We test this view by applying a model that linearly relates electricity futures prices to the marginal costs of production and calculate the log-likelihood of different time-varying and constant specifications of the coefficients. To do so, we formulate the model in state-space form and apply the Kalman Filter to observe the dynamics of the coefficients. We analyse historical prices of futures contracts with different delivery periods (calendar year and seasons, peak and off-peak) from Germany and the U.K. The results indicate that analysts should choose a time-varying specification to relate the futures price of power to prices of underlying fundamentals

    Impact of human CA8 on thermal antinociception in relation to morphine equivalence in mice

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    Recently, we showed that murine dorsal root ganglion (DRG) Car8 expression is a cis-regulated eQTL that determines analgesic responses. In this report, we show that transduction through sciatic nerve injection of DRG with human wild-type carbonic anhydrase-8 using adeno-associated virus viral particles (AAV8-V5-CA8WT) produces analgesia in naive male C57BL/6J mice and antihyperalgesia after carrageenan treatment. A peak mean increase of about 4 s in thermal hindpaw withdrawal latency equaled increases in thermal withdrawal latency produced by 10 mg/kg intraperitoneal morphine in these mice. Allometric conversion of this intraperitoneal morphine dose in mice equals an oral morphine dose of about 146 mg in a 60-kg adult. Our work quantifies for the first time analgesia and antihyperalgesia in an inflammatory pain model after DRG transduction by CA8 gene therapy

    Prominent microglial inclusions in transgenic mouse models of α-synucleinopathy that are distinct from neuronal lesions.

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    Alpha-synucleinopathies are a group of progressive neurodegenerative disorders, characterized by intracellular deposits of aggregated α-synuclein (αS). The clinical heterogeneity of these diseases is thought to be attributed to conformers (or strains) of αS but the contribution of inclusions in various cell types is unclear. The aim of the present work was to study αS conformers among different transgenic (TG) mouse models of α-synucleinopathies. To this end, four different TG mouse models were studied (Prnp-h[A53T]αS; Thy1-h[A53T]αS; Thy1-h[A30P]αS; Thy1-mαS) that overexpress human or murine αS and differed in their age-of-symptom onset and subsequent disease progression. Postmortem analysis of end-stage brains revealed robust neuronal αS pathology as evidenced by accumulation of αS serine 129 (p-αS) phosphorylation in the brainstem of all four TG mouse lines. Overall appearance of the pathology was similar and only modest differences were observed among additionally affected brain regions. To study αS conformers in these mice, we used pentameric formyl thiophene acetic acid (pFTAA), a fluorescent dye with amyloid conformation-dependent spectral properties. Unexpectedly, besides the neuronal αS pathology, we also found abundant pFTAA-positive inclusions in microglia of all four TG mouse lines. These microglial inclusions were also positive for Thioflavin S and showed immunoreactivity with antibodies recognizing the N-terminus of αS, but were largely p-αS-negative. In all four lines, spectral pFTAA analysis revealed conformational differences between microglia and neuronal inclusions but not among the different mouse models. Concomitant with neuronal lesions, microglial inclusions were already present at presymptomatic stages and could also be induced by seeded αS aggregation. Although nature and significance of microglial inclusions for human α-synucleinopathies remain to be clarified, the previously overlooked abundance of microglial inclusions in TG mouse models of α-synucleinopathy bears importance for mechanistic and preclinical-translational studies
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