7,786 research outputs found

    Genomic dynamics of transposable elements in the western clawed frog (Silurana tropicalis)

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    Transposable elements (TEs) are repetitive DNA sequences that can make new copies of themselves that are inserted elsewhere in a host genome. The abundance and distributions of TEs vary considerably among phylogenetically diverse hosts. With the aim of exploring the basis of this variation, we evaluated correlations between several genomic variables and the presence of TEs and non-TE repeats in the complete genome sequence of the Western clawed frog (Silurana tropicalis). This analysis reveals patterns of TE insertion consistent with gene disruption but not with the insertional preference model. Analysis of non-TE repeats recovered unique features of their genome-wide distribution when compared with TE repeats, including no strong correlation with exons and a particularly strong negative correlation with GC content. We also collected polymorphism data from 25 TE insertion sites in 19 wild-caught S. tropicalis individuals. DNA transposon insertions were fixed at eight of nine sites and at a high frequency at one of nine, whereas insertions of long terminal repeat (LTR) and non-LTR retrotransposons were fixed at only 4 of 16 sites and at low frequency at 12 of 16. A maximum likelihood model failed to attribute these differences in insertion frequencies to variation in selection pressure on different classes of TE, opening the possibility that other phenomena such as variation in rates of replication or duration of residence in the genome could play a role. Taken together, these results identify factors that sculpt heterogeneity in TE distribution in S. tropicalis and illustrate that genomic dynamics differ markedly among TE classes and between TE and non-TE repeats.published_or_final_versio

    The rationale for quadrivalent influenza vaccines

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    Two antigenically distinct lineages of influenza B viruses have circulated globally since 1985. However, licensed trivalent seasonal influenza vaccines contain antigens from only a single influenza B virus and thus provide limited immunity against circulating influenza B strains of the lineage not present in the vaccine. In recent years, predictions about which B lineage will predominate in an upcoming influenza season have been no better than chance alone, correct in only 5 of the 10 seasons from 2001 to 2011. Consequently, seasonal influenza vaccines could be improved by inclusion of influenza B strains of both lineages. The resulting quadrivalent influenza vaccines would allow influenza vaccination campaigns to respond more effectively to current global influenza epidemiology. Manufacturing capacity for seasonal influenza vaccines has increased sufficiently to supply quadrivalent influenza vaccines, and methods to identify the influenza B strains to include in such vaccines are in place. Multiple manufacturers have initiated clinical studies of quadrivalent influenza vaccines. Data from those studies, taken together with epidemiologic data regarding the burden of disease caused by influenza B infections, will determine the safety, effectiveness, and benefit of utilizing quadrivalent vaccines for the prevention of seasonal influenza disease

    Association between two CHRNA3 variants and susceptibility of lung cancer: a meta-analysis

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    An Ultrafast and Stable High-Entropy Metallic Glass Electrode for Alkaline Hydrogen Evolution Reaction

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    A new type of high-entropy alloy with a composition of Pt25Pd25Ni25P25(at.%) and an amorphous structure, referred to as a high-entropy metallic glass (HEMG), was developed by a scalable metallurgical technique for efficient hydrogen evolution reaction (HER). The achieved overpotential was as low as 19.8 mV at a current density of 10 mA cm-2while maintaining an ultrareliable performance for 60 h in 1.0 M KOH solution, exhibiting 5- and 10-times higher performance than those of traditional Pt60Ni15P25and Pd40Ni40P20metallic glasses, respectively, and also surpassing the benchmark performance of commercial Pt/C nanoparticles and pure Pt sheet. Experimental and theoretical results revealed that the enhanced HER activity was ascribed to a synergistic function of multiprincipal components that optimized the electronic structure to accelerate the rate-determining steps in HER. Moreover, the unique long-range disordered structure provided a high density of unsaturated atomic coordination that was able to improve the amount of electrochemically active sites. This bulk HEMG strategy paves the way for the development of flexible freestanding electrodes for water splitting applications

    Investigation on why the practice of rural residence land exchange is different under development driven condition and disaster induced condition

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    Different mechanisms of cis-9,trans-11- and trans-10,cis-12- conjugated linoleic acid affecting lipid metabolism in 3T3-L1 cells

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    Conjugated linoleic acid (CLA) has been shown to reduce body fat mass in various experimental animals. It is valuable to identify its influence on enzymes involved in energy expenditure, apoptosis, fatty acid oxidation and lipolysis. We investigated isomer-specific effects of high dose, long treatment of CLA (75.4 Īœmol/L, 8 days) on protein and gene expression of these enzymes in cultured 3T3-L1 cells. Proteomics identified significant up- or down-regulation of 52 proteins by either CLA isomer. Protein and gene expression of uncoupling protein (UCP) 1, UCP3, perilipin and peroxisome proliferator-activated receptor (PPAR) Ī± increased whereas UCP2 reduced for both CLA isomers. And eight-day treatment of trans-10,. cis-12 CLA, but not cis-9,. trans-11 CLA, significantly up-regulated protein and mRNA levels of PKA (P<05), CPT-1 and TNF-Ī± (P<01). Compared to protein expression, both isomers did not significantly influence the mRNA expression of HSL, ATGL, ACO and leptin. In conclusion, high-dose, long treatment of cis-9,. trans-11 CLA did not promote apoptosis, fatty acid oxidation and lipolysis in adipocytes, but may induce an increase in energy expenditure. trans-10,. cis-12 CLA exhibited greater influence on lipid metabolism, stimulated adipocyte energy expenditure, apoptosis and fatty acid oxidation, but its effect on lipolysis was not obvious. Ā© 2010 Elsevier Inc.postprin
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