195 research outputs found

    Hydrophobic coating of solid materials by plasma-polymerized thin film using tetrafluoroethylene

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    Glass slides were coated with plasma-polymerized tetrafluoroethylene films of different thickness using the glow discharge technique in a tube-shaped chamber, and the plasma conditions, film growth rates, light permeability of the polymer films, and particle bond strength in the polymer films were studied. Ashed sections of mouse organs and ashed bacillus spores were also coated to give them hydrophobic treatment without damaging their shapes or appearance. The hydrophobic coating of the specimens was successful, and the fine ash patterns were strongly fixed onto the glass slides, making permanent preparations

    Serial selection for invasiveness increases expression of miR-143/miR-145 in glioblastoma cell lines

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    <p>Abstract</p> <p>Background</p> <p>Glioblastoma multiforme (GBM) is the most common primary central nervous system malignancy and its unique invasiveness renders it difficult to treat. This invasive phenotype, like other cellular processes, may be controlled in part by microRNAs - a class of small non-coding RNAs that act by altering the expression of targeted messenger RNAs. In this report, we demonstrate a straightforward method for creating invasive subpopulations of glioblastoma cells (IM3 cells). To understand the correlation between the expression of miRNAs and the invasion, we fully profiled 1263 miRNAs on six different cell lines and two miRNAs, miR-143 and miR-145, were selected for validation of their biological properties contributing to invasion. Further, we investigated an ensemble effect of both miR-143 and miR-145 in promoting invasion.</p> <p>Methods</p> <p>By repeated serial invasion through Matrigel<sup>®</sup>-coated membranes, we isolated highly invasive subpopulations of glioma cell lines. Phenotypic characterization of these cells included <it>in vitro </it>assays for proliferation, attachment, and invasion. Micro-RNA expression was compared using miRCURY arrays (Exiqon). In situ hybridization allowed visualization of the regional expression of miR-143 and miR-145 in tumor samples, and antisense probes were used investigate <it>in vitro </it>phenotypic changes seen with knockdown in their expression.</p> <p>Results</p> <p>The phenotype we created in these selected cells proved stable over multiple passages, and their microRNA expression profiles were measurably different. We found that two specific microRNAs expressed from the same genetic locus, miR-143 and miR-145, were over-expressed in our invasive subpopulations. Further, we also found that combinatorial treatment of these cells with both antisense-miRNAs (antimiR-143 and -145) will abrogated their invasion without decreasing cell attachment or proliferation.</p> <p>Conclusions</p> <p>To best of our knowledge, these data demonstrate for the first time that miR-143 and miR-145 regulate the invasion of glioblastoma and that miR-143 and -145 could be potential therapeutic target for anti-invasion therapies of glioblastoma patients.</p

    Pin1 Modulates the Type 1 Immune Response

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    BACKGROUND/ABSTRACT: Immune responses initiated by T cell receptor (TCR) and costimulatory molecule mediated signaling culminate in maximal cytokine mRNA production and stability. The transcriptional responses to co-stimulatory T cell signalling involve calcineurin and NF-AT, which can be antagonized by interference with the cis-trans peptidyl-prolyl isomerases (PPIase), cyclophilin A and FKBP. Signalling molecules downstream of CD28 which are essential for the stabilization of cytokine mRNAs are largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: We now show that Pin1, a third member of the PPIase family mediates the post-transcriptional regulation of Th1 cytokines by activated T cells. Blockade of Pin1 by pharmacologic or genetic means greatly attenuated IFN-γ, IL-2 and CXCL-10 mRNA stability, accumulation and protein expression after cell activation. In vivo, Pin1 blockade prevented both the acute and chronic rejection of MHC mismatched, orthotopic rat lung transplants by reducing the expression of IFN-γ and CXCL-10. Combined transcriptional and post-transcriptional blockade with cyclosporine A and the Pin1 inhibitor, juglone, was synergistic. CONCLUSIONS/SIGNIFICANCE: These data suggest Pin1 inhibitors should be explored for use as immunosuppressants and employed with available calcineurin inhibitors to reduce toxicity and enhance effectiveness

    Hepatic wound repair

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    BACKGROUND: Human chronic liver diseases (CLDs) with different aetiologies rely on chronic activation of wound healing that represents the driving force for fibrogenesis progression (throughout defined patterns of fibrosis) to the end stage of cirrhosis and liver failure. ISSUES: Fibrogenesis progression has a major worldwide clinical impact due to the high number of patients affected by CLDs, increasing mortality rate, incidence of hepatocellular carcinoma and shortage of organ donors for liver transplantation. BASIC SCIENCE ADVANCES: Liver fibrogenesis is sustained by a heterogeneous population of profibrogenic hepatic myofibroblasts (MFs), the majority being positive for alpha smooth muscle actin (alphaSMA), that may originate from hepatic stellate cells and portal fibroblasts following a process of activation or from bone marrow-derived cells recruited to damaged liver and, in a method still disputed, by a process of epithelial to mesenchymal transition (EMT) involving cholangiocytes and hepatocytes. Recent experimental and clinical data have identified, at tissue, cellular and molecular level major profibrogenic mechanisms: (a) chronic activation of the wound-healing reaction, (b) oxidative stress and related reactive intermediates, and (c) derangement of epithelial-mesenchymal interactions. CLINICAL CARE RELEVANCE: Liver fibrosis may regress following specific therapeutic interventions able to downstage or, at least, stabilise fibrosis. In cirrhotic patients, this would lead to a reduction of portal hypertension and of the consequent clinical complications and to an overall improvement of liver function, thus extending the complication-free patient survival time and reducing the need for liver transplantation. CONCLUSION: Emerging mechanisms and concepts related to liver fibrogenesis may significantly contribute to clinical management of patients affected by CLDs

    Do Termites Avoid Carcasses? Behavioral Responses Depend on the Nature of the Carcasses

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    BACKGROUND: Undertaking behavior is a significant adaptation to social life in enclosed nests. Workers are known to remove dead colony members from the nest. Such behavior prevents the spread of pathogens that may be detrimental to a colony. To date, little is known about the ethological aspects of how termites deal with carcasses. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, we tested the responses to carcasses of four species from different subterranean termite taxa: Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) (lower termites) and Microcerotermes crassus Snyder and Globitermes sulphureus Haviland (higher termites). We also used different types of carcasses (freshly killed, 1-, 3-, and 7-day-old, and oven-killed carcasses) and mutilated nestmates to investigate whether the termites exhibited any behavioral responses that were specific to carcasses in certain conditions. Some behavioral responses were performed specifically on certain types of carcasses or mutilated termites. C. formosanus and R. speratus exhibited the following behaviors: (1) the frequency and time spent in antennating, grooming, and carcass removal of freshly killed, 1-day-old, and oven-killed carcasses were high, but these behaviors decreased as the carcasses aged; (2) the termites repeatedly crawled under the aging carcass piles; and (3) only newly dead termites were consumed as a food source. In contrast, M. crassus and G. sulphureus workers performed relatively few behavioral acts. Our results cast a new light on the previous notion that termites are necrophobic in nature. CONCLUSION: We conclude that the behavioral response towards carcasses depends largely on the nature of the carcasses and termite species, and the response is more complex than was previously thought. Such behavioral responses likely are associated with the threat posed to the colony by the carcasses and the feeding habits and nesting ecology of a given species

    Taking a more nuanced look at behavior change for demand reduction in the illegal wildlife trade

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    The illegal wildlife trade threatens the future of many species, and undermines economies and livelihoods. Conservationists have largely responded with supply‐side interventions, such as antipoaching patrols, but these often fail to stem the tide of wildlife trafficking. There is now increasing interest in demand‐side interventions, which seek to lower poaching pressure on sought‐after species by reducing consumer's desire for, and purchase of, specific wildlife products. Individual behavior change approaches, from environmental education to social marketing, have been widely advocated by academics, practitioners, and policy makers. However, this is an emerging field and we lack the breadth of evidence needed to understand and predict the potential outcomes of demand reduction interventions. To help us gain broader insights, we examine the literature from public health and international development on the effectiveness of behavior change interventions, and critique the current conceptualization of strategies for reducing consumer demand in the illegal wildlife trade. We show that behavior change is difficult to achieve and interventions may have unintended and undesirable consequences because of unaddressed systemic, cultural and environmental drivers, and limited resourcing. We conclude that some sections of the conservation community are advocating a shift from one reductionist approach based on limiting supply, to another based on limiting demand, and argue that conservationists should learn from the public health and international development projects that have integrated systems thinking. By accounting for the multiple interactions and synergies between different factors in the wildlife trade, we can develop more strategic approaches to protecting endangered species

    Leptin as a critical regulator of hepatocellular carcinoma development through modulation of human telomerase reverse transcriptase

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    <p>Abstract</p> <p>Background</p> <p>Numerous epidemiological studies have documented that obesity is associated with hepatocellular carcinoma (HCC). The aim of this study was to investigate the biological actions regulated by leptin, the obesity biomarker molecule, and its receptors in HCC and the correlation between leptin and human telomerase reverse transcriptase (hTERT), a known mediator of cellular immortalization.</p> <p>Methods</p> <p>We investigated the relationship between leptin, leptin receptors and hTERT mRNA expression in HCC and healthy liver tissue samples. In HepG2 cells, chromatin immunoprecipitation assay was used to study signal transducer and activator of transcription-3 (STAT3) and myc/mad/max transcription factors downstream of leptin which could be responsible for hTERT regulation. Flow cytometry was used for evaluation of cell cycle modifications and MMP1, 9 and 13 expression after treatment of HepG2 cells with leptin. Blocking of leptin's expression was achieved using siRNA against leptin and transfection with liposomes.</p> <p>Results</p> <p>We showed, for the first time, that leptin's expression is highly correlated with hTERT expression levels in HCC liver tissues. We also demonstrated in HepG2 cells that leptin-induced up-regulation of hTERT and TA was mediated through binding of STAT3 and Myc/Max/Mad network proteins on <it>hTERT </it>promoter. We also found that leptin could affect hepatocellular carcinoma progression and invasion through its interaction with cytokines and matrix mettaloproteinases (MMPs) in the tumorigenic microenvironment. Furthermore, we showed that histone modification contributes to leptin's gene regulation in HCC.</p> <p>Conclusions</p> <p>We propose that leptin is a key regulator of the malignant properties of hepatocellular carcinoma cells through modulation of hTERT, a critical player of oncogenesis.</p

    Molecular Phylogeny and Evolution of Parabasalia with Improved Taxon Sampling and New Protein Markers of Actin and Elongation Factor-1α

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    BACKGROUND: Inferring the evolutionary history of phylogenetically isolated, deep-branching groups of taxa-in particular determining the root-is often extraordinarily difficult because their close relatives are unavailable as suitable outgroups. One of these taxonomic groups is the phylum Parabasalia, which comprises morphologically diverse species of flagellated protists of ecological, medical, and evolutionary significance. Indeed, previous molecular phylogenetic analyses of members of this phylum have yielded conflicting and possibly erroneous inferences. Furthermore, many species of Parabasalia are symbionts in the gut of termites and cockroaches or parasites and therefore formidably difficult to cultivate, rendering available data insufficient. Increasing the numbers of examined taxa and informative characters (e.g., genes) is likely to produce more reliable inferences. PRINCIPAL FINDINGS: Actin and elongation factor-1α genes were identified newly from 22 species of termite-gut symbionts through careful manipulations and seven cultured species, which covered major lineages of Parabasalia. Their protein sequences were concatenated and analyzed with sequences of previously and newly identified glyceraldehyde-3-phosphate dehydrogenase and the small-subunit rRNA gene. This concatenated dataset provided more robust phylogenetic relationships among major groups of Parabasalia and a more plausible new root position than those previously reported. CONCLUSIONS/SIGNIFICANCE: We conclude that increasing the number of sampled taxa as well as the addition of new sequences greatly improves the accuracy and robustness of the phylogenetic inference. A morphologically simple cell is likely the ancient form in Parabasalia as opposed to a cell with elaborate flagellar and cytoskeletal structures, which was defined as most basal in previous inferences. Nevertheless, the evolution of Parabasalia is complex owing to several independent multiplication and simplification events in these structures. Therefore, systematics based solely on morphology does not reflect the evolutionary history of parabasalids
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