391 research outputs found

    PKR is not obligatory for high-fat diet-induced obesity and its associated metabolic and inflammatory complications

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    Protein kinase R (PKR) has previously been suggested to mediate many of the deleterious consequences of a high-fat diet (HFD). However, previous studies have observed substantial phenotypic variability when examining the metabolic consequences of PKR deletion. Accordingly, herein, we have re-examined the role of PKR in the development of obesity and its associated metabolic complications in vivo as well as its putative lipid-sensing role in vitro. Here we show that the deletion of PKR does not affect HFD-induced obesity, hepatic steatosis or glucose metabolism, and only modestly affects adipose tissue inflammation. Treatment with the saturated fatty acid palmitate in vitro induced comparable levels of inflammation in WT and PKR KO macrophages, demonstrating that PKR is not necessary for the sensing of pro-inflammatory lipids. These results challenge the proposed role for PKR in obesity, its associated metabolic complications and its role in lipid-induced inflammation

    Over-expressing the soluble gp130-Fc does not ameliorate methionine and choline deficient diet-induced non alcoholic steatohepatitis in mice

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    Non-alcoholic steatohepatitis (NASH) is a liver disease with the potential to lead to cirrhosis and hepatocellular carcinoma. Interleukin-6 (IL-6) has been implicated in the pathogenesis of NASH, with the so-called IL-6 ‘trans-signaling’ cascade being responsible for the pro-inflammatory actions of this cytokine. We aimed to block IL-6 ‘trans-signaling’, using a transgenic mouse that overexpresses human soluble glycoprotein130 (sgp130Fc Tg mice) fed a commonly used dietary model of inducing NASH (methionine and choline deficient-diet; MCD diet) and hypothesized that markers of NASH would be ameliorated in such mice. Sgp130Fc Tg and littermate control mice were fed a MCD or control diet for 4 weeks. The MCD diet induced many hallmarks of NASH including hepatomegaly, steatosis, and liver inflammation. However, in contrast with other mouse models and, indeed, human NASH, the MCD diet model did not increase the mRNA or protein expression of IL-6. Not surprisingly, therefore, markers of MCD diet-induced NASH were unaffected by sgp130Fc transgenic expression. While the MCD diet model induces many pathophysiological markers of NASH, it does not induce increased IL-6 expression in the liver, a key hallmark of human NASH. We, therefore, caution the use of the MCD diet as a viable mouse model of NASH

    Dynamical origins of heat capacity changes in enzyme-catalysed reactions

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    Heat capacity changes affect the temperature dependence of enzyme catalysis, with implications for thermoadaptation, however their physical basis is unknown. Here the authors show that heat capacity changes are calculable by simulation, revealing distinct dynamical contributions from regions remote from the active site

    Ernst Freund as Precursor of the Rational Study of Corporate Law

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    Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe

    Towards an Economy of Higher Education

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    This paper draws a distinction between ways thinking and acting, and hence of policy and practice in higher education, in terms of different kinds of economy: economies of exchange and economies of excess. Crucial features of economies of exchange are outlined and their presence in prevailing conceptions of teaching and learning is illustrated. These are contrasted with other possible forms of practice, which in turn bring to light the nature of an economy of excess. In more philosophical terms, and to expand on the picture, economies of excess are elaborated with reference, first, to the understanding of alterity in the work of Emmanuel Levinas and, second, to the idea of Dionysian intensity that is to be found in Nietzsche. In the light of critical comment on some current directions in policy and practice, the implications of these ways of thinking for the administrator, the teacher and the student in higher education are explored

    Statistical epistasis between candidate gene alleles for complex tuber traits in an association mapping population of tetraploid potato

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    Association mapping using DNA-based markers is a novel tool in plant genetics for the analysis of complex traits. Potato tuber yield, starch content, starch yield and chip color are complex traits of agronomic relevance, for which carbohydrate metabolism plays an important role. At the functional level, the genes and biochemical pathways involved in carbohydrate metabolism are among the best studied in plants. Quantitative traits such as tuber starch and sugar content are therefore models for association genetics in potato based on candidate genes. In an association mapping experiment conducted with a population of 243 tetraploid potato varieties and breeding clones, we previously identified associations between individual candidate gene alleles and tuber starch content, starch yield and chip quality. In the present paper, we tested 190 DNA markers at 36 loci scored in the same association mapping population for pairwise statistical epistatic interactions. Fifty marker pairs were associated mainly with tuber starch content and/or starch yield, at a cut-off value of q ≤ 0.20 for the experiment-wide false discovery rate (FDR). Thirteen marker pairs had an FDR of q ≤ 0.10. Alleles at loci encoding ribulose-bisphosphate carboxylase/oxygenase activase (Rca), sucrose phosphate synthase (Sps) and vacuolar invertase (Pain1) were most frequently involved in statistical epistatic interactions. The largest effect on tuber starch content and starch yield was observed for the paired alleles Pain1-8c and Rca-1a, explaining 9 and 10% of the total variance, respectively. The combination of these two alleles increased the means of tuber starch content and starch yield. Biological models to explain the observed statistical epistatic interactions are discussed

    Extent and structure of linkage disequilibrium in canola quality winter rapeseed (Brassica napus L.)

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    Linkage disequilibrium was investigated in canola quality winter rapeseed to analyze (1) the prospects for whole-genome association analyses and (2) the impact of the recent breeding history of rapeseed on linkage disequilibrium. A total of 845 mapped AFLP markers with allele frequencies ≥0.1 were used for the analysis of linkage disequilibrium in a population of 85 canola quality winter rapeseed genotypes. A low overall level of linkage disequilibrium was found with a mean r2 of only 0.027 over all 356,590 possible marker pairs. At a significance threshold of P = 2.8 × 10−7, which was derived by a Bonferroni correction from a global α-level of 0.1, only 0.78% of the marker pairs were in significant linkage disequilibrium. Among physically linked marker pairs, the level of linkage disequilibrium was about five times higher with more than 10% of marker pairs in significant linkage disequilibrium. Linkage disequilibrium decayed rapidly with distance between linked markers with high levels of linkage disequilibrium extending only for about 2 cM. Owing to the rapid decay of linkage disequilibrium with distance association analyses in canola quality rapeseed will have a significantly higher resolution than QTL analyses in segregating populations by interval mapping, but much larger number of markers will be necessary to cover the whole genome. A major impact of the recent breeding history of rapeseed on linkage disequilibrium could not be observed

    Russia’s Legal Transitions: Marxist Theory, Neoclassical Economics and the Rule of Law

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    We review the role of economic theory in shaping the process of legal change in Russia during the two transitions it experienced during the course of the twentieth century: the transition to a socialist economy organised along the lines of state ownership of the means of production in the 1920s, and the transition to a market economy which occurred after the fall of the Soviet Union in the 1990s. Despite differences in methodology and in policy implications, Marxist theory, dominant in the 1920s, and neoclassical economics, dominant in the 1990s, offered a similarly reductive account of law as subservient to wider economic forces. In both cases, the subordinate place accorded to law undermined the transition process. Although path dependence and history are frequently invoked to explain the limited development of the rule of law in Russia during the 1990s, policy choices driven by a deterministic conception of law and economics also played a role.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s40803-015-0012-
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