161 research outputs found

    Type I procollagen processing in the developing chick

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    An Experience Sampling Study of Expressing Affect, Daily Affective Well-Being, Relationship Quality and Perceived Performance

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    Few studies have directly examined the processes through which workers use job resources, such as job control and social support, to regulate affect. We focused on affective expression, which is a specific form of affect regulation. We investigated the extent to which workers used both job control and social support to express affect. Thirty-nine call centre workers provided data up to four times a day over five consecutive working days (number of observations = 272). Executing job control to allow workers to express affect was related to using social support to express affect. Workers' understanding of their personal goals mediated relationships between using social support to express affect and four outcomes (negative affect, positive affect, perceived performance, and quality of workplace relationships). Perceived empathy mediated relationships between using social support to express affect and three outcomes (negative affect, positive affect, and quality of workplace relationships). The findings indicated that (1) one job resource can be used to facilitate using another job resource for affect regulation and (2) different job resources may play different roles in conferring benefits from affective expression

    IDH1: Linking Metabolism and Epigenetics

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    Mutations in genes encoding enzymes of the tricarboxylic acid cycle often contribute to cancer development and progression by disrupting cell metabolism and altering the epigenetic landscape. This is exemplified by the isoforms of isocitrate dehydrogenase (IDH1/2), which metabolize isocitrate to α-Ketoglutarate (α-KG). Gain of function mutations in IDH1 or IDH2 result in reduced levels of α-KG as a result of increased formation of D-2-Hydroxyglutarate (2-HG). α-KG is an essential co-factor for certain histone and DNA demethylases, while 2-HG is a competitive inhibitor. These IDH1/2 mutations are thought to result in hypermethylated histones and DNA which in turn alters gene expression and drives cancer progression. While this model seems to be generally accepted in the field, the exact molecular mechanisms still remain elusive. How much of this model has been rigorously demonstrated and what is just being assumed? Are the effects genome-wide or focused on specific loci? This Perspective aims at elucidating the key questions that remain to be addressed, the experimental techniques that could be used to gain further insight into the molecular mechanisms involved and the additional consequences of these mutations beyond DNA and protein methylation

    Spt4 facilitates the movement of RNA polymerase II through the +2 nucleosomal barrier

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    We thank Frank Holstege for providing the S.cerevisiae Anchor Away strains, Lidia Vasilieva for Rpb9 FLAG-tagged S.pombe strain, Sabrina Liberatori and Shabaz Mohammed for proteomics, and Micron Oxford for imaging support.Peer reviewe

    The Effect of Dietary Supplementation of Green Tea Catechins on Cardiovascular Disease Risk Markers in Humans:A Systematic Review of Clinical Trials

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    Green tea catechins (GTCs) are secondary plant metabolites that have been associated with health benefits in human trials. As such, they have the potential to reduce cardiovascular disease (CVD) risk; however, results are not consistent. This systematic review of the published data assessed the putative effect of GTCs supplementation on anthropometric, blood pressure, and biochemical measures associated with CVD risk. It was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines exploring four major electronic databases (MEDLINE, Cochrane Library, Web of Science, and Scopus). Studies were included if they were published in peer-reviewed journals in English from 1990 until October 2015, and were human double-blind randomized and placebo-controlled trials (RCTs). From 122,428 articles initially identified, after two levels of screening, seven studies met the inclusion criteria. The review revealed consistent and significant (<i>p</i> ≤ 0.05) reductions in body mass index (BMI), blood pressure and plasma lipids; however, this effect would have been less if between-group effects had been considered. The current evidence base also has considerable methodological limitations due to suboptimal statistical methods used in data analyses. Future research efforts must aim to rectify this paucity of evidence with well-designed and well-reported prospective studies

    The Effect of L-Theanine Incorporated in a Functional Food Product (Mango Sorbet) on Physiological Responses in Healthy Males: A Pilot Randomised Controlled Trial

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    Consumption of L-Theanine (L-THE) has been associated with a sensation of relaxation, as well as a reduction of stress. However, these physiological responses have yet to be elucidated in humans where L-THE is compared alongside food or as a functional ingredient within the food matrix. The aim of this study was to determine the physiological responses of a single intake of a potential functional food product (mango sorbet) containing L-THE (ms-L-THE; 200 mgw/w) in comparison to a flavour and colour-matched placebo (ms). Eighteen healthy male participants were recruited in this randomised, double-blind, placebo-controlled trial. The participants were required to consume ms-L-THE or placebo and their blood pressure (BP) (systolic and diastolic), heart rate (HR), and heart rate variability (HRV) were monitored continuously over 90 minutes. Eleven males (age 27.7 ± 10.8 years) completed the study. Changes in area under the curve for systolic and diastolic blood pressure and HRV over the 90 minute observation period indicated no differences between the three conditions (all p > 0.05) or within individual groups (all p > 0.05). The values for heart rate were also not different in the placebo group (p = 0.996) and treatment group (p = 0.066), while there was a difference seen at the baseline (p = 0.003). Based on the findings of this study, L-THE incorporated in a food matrix (mango sorbet) demonstrated no reduction in BP or HR and showed no significant parasympathetic interaction as determined by HRV high-frequency band and low-frequency/high-frequency ratio. Further studies should be focussed towards the comparison of pure L-THE and incorporation within the food matrix to warrant recommendations of L-THE alongside food consumption

    Repressive and non-repressive chromatin at native telomeres in Saccharomyces cerevisiae

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    <p>Abstract</p> <p>Background</p> <p>In <it>Saccharomyces cerevisiae </it>genes that are located close to a telomere can become transcriptionally repressed by an epigenetic process known as telomere position effect. There is large variation in the level of the telomere position effect among telomeres, with many native ends exhibiting little repression.</p> <p>Results</p> <p>Chromatin analysis, using microccocal nuclease and indirect end labelling, reveals distinct patterns for ends with different silencing states. Differences were observed in the promoter accessibility of a subtelomeric reporter gene and a characteristic array of phased nucleosomes was observed on the centromere proximal side of core X at a repressive end. The silent information regulator proteins 2 - 4, the yKu heterodimer and the subtelomeric core X element are all required for the maintenance of the chromatin structure of repressive ends. However, gene deletions of particular histone modification proteins can eliminate the silencing without the disruption of this chromatin structure.</p> <p>Conclusion</p> <p>Our data identifies chromatin features that correlate with the silencing state and indicate that an array of phased nucleosomes is not sufficient for full repression.</p

    A role for Snf2-related nucleosome-spacing enzymes in genome-wide nucleosome organization

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    The positioning of nucleosomes within the coding regions of eukaryotic genes is aligned with respect to transcriptional start sites. This organization is likely to influence many genetic processes, requiring access to the underlying DNA. Here, we show that the combined action of Isw1 and Chd1 nucleosome-spacing enzymes is required to maintain this organization. In the absence of these enzymes, regular positioning of the majority of nucleosomes is lost. Exceptions include the region upstream of the promoter, the +1 nucleosome, and a subset of locations distributed throughout coding regions where other factors are likely to be involved. These observations indicate that adenosine triphosphate-dependent remodeling enzymes are responsible for directing the positioning of the majority of nucleosomes within the Saccharomyces cerevisiae genome

    Analysis of C. elegans intestinal gene expression and polyadenylation by fluorescence-activated nuclei sorting and 3′-end-seq

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    Despite the many advantages of Caenorhabditis elegans, biochemical approaches to study tissue-specific gene expression in post-embryonic stages are challenging. Here, we report a novel experimental approach for efficient determination of tissue-specific transcriptomes involving the rapid release and purification of nuclei from major tissues of post-embryonic animals by fluorescence-activated nuclei sorting (FANS), followed by deep sequencing of linearly amplified 3′-end regions of transcripts (3′-end-seq). We employed these approaches to compile the transcriptome of the developed C. elegans intestine and used this to analyse tissue-specific cleavage and polyadenylation. In agreement with intestinal-specific gene expression, highly expressed genes have enriched GATA-elements in their promoter regions and their functional properties are associated with processes that are characteristic for the intestine. We systematically mapped pre-mRNA cleavage and polyadenylation sites, or polyA sites, including more than 3000 sites that have previously not been identified. The detailed analysis of the 3′-ends of the nuclear mRNA revealed widespread alternative polyA site use (APA) in intestinally expressed genes. Importantly, we found that intestinal polyA sites that undergo APA tend to have U-rich and/or A-rich upstream auxiliary elements that may contribute to the regulation of 3′-end formation in the intestin
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