44 research outputs found

    Characterization of ovine hepatic gene expression profiles in response to Escherichia coli lipopolysaccharide using a bovine cDNA microarray

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    BACKGROUND: During systemic gram-negative bacterial infections, lipopolysaccharide (LPS) ligation to the hepatic Toll-like receptor-4 complex induces the production of hepatic acute phase proteins that are involved in the host response to infection and limit the associated inflammatory process. Identifying the genes that regulate this hepatic response to LPS in ruminants may provide insight into the pathogenesis of bacterial diseases and eventually facilitate breeding of more disease resistant animals. The objective of this research was to profile the expression of ovine hepatic genes in response to Escherichia coli LPS challenge (0, 200, 400 ng/kg) using a bovine cDNA microarray and quantitative real-time PCR (qRT-PCR). RESULTS: Twelve yearling ewes were challenged iv with E. coli LPS (0, 200, 400 ng/kg) and liver biopsies were collected 4–5 hours post-challenge to assess hepatic gene expression profiles by bovine cDNA microarray and qRT-PCR analyses. The expression of CD14, C3, IL12R, NRAMP1, SOD and IGFBP3 genes was down regulated, whereas the expression of ACTHR, IFNαR, CD1, MCP-1 and GH was increased during LPS challenge. With the exception of C3, qRT-PCR analysis of 7 of these genes confirmed the microarray results and demonstrated that GAPDH is not a suitable housekeeping gene in LPS challenged sheep. CONCLUSION: We have identified several potentially important genes by bovine cDNA microarray and qRT-PCR analyses that are differentially expressed during the ovine hepatic response to systemic LPS challenge. Their potential role in regulating the inflammatory response to LPS warrants further investigation

    Alkali metal storage mechanism in organic semiconductor of perylene-3,4,9,10-tetracarboxylicdianhydride

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    Organic semiconductor-based electrode materials are promising candidates for energy storage devices due to their high capacity, excellent flexibility, low cost and resource sustainability. The alkali metal storage mechanisms on various active functional groups of the organic materials, however, are still not clear at the molecular scale. It is essential to conduct systematic mechanism studies for the alkali storage behaviors in organic electrode materials. Here, the chemical and electronic structure evolutions upon the deposition of lithium (Li) and sodium (Na) on a model organic semiconductor electrode material of perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA), have been investigated by in-situ x-ray photoemission spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), near edge x-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory (DFT) calculations. It reveals that Li/Na can react with the carbonyl oxygen and increase the electron density within the PTCDA perylene. Moreover, the band-bending like features are observed on PTCDA film upon Li/Na interaction. Our experimental results and theoretical calculations indicate that reactions on carbonyl groups and charge redistribution are crucial for the Li/Na storage process, which shed light on comprehensive insights for the Li/Na storage behaviors on organic semiconductor-based electrode materials.Ministry of Education (MOE)Authors acknowledge the financial support from Singapore MOE grant R143-000-A29-112 and Academic Research Fund Tier 1 (RG104/ 18), as well as the computing resources from National Supercomputing Centre Singapore
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