4,199 research outputs found

    Cell-type specific analysis of translating RNAs in developing flowers reveals new levels of control

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    Determining both the expression levels of mRNA and the regulation of its translation is important in understanding specialized cell functions. In this study, we describe both the expression profiles of cells within spatiotemporal domains of the Arabidopsis thaliana flower and the post-transcriptional regulation of these mRNAs, at nucleotide resolution. We express a tagged ribosomal protein under the promoters of three master regulators of flower development. By precipitating tagged polysomes, we isolated cell type specific mRNAs that are probably translating, and quantified those mRNAs through deep sequencing. Cell type comparisons identified known cell-specific transcripts and uncovered many new ones, from which we inferred cell type-specific hormone responses, promoter motifs and coexpressed cognate binding factor candidates, and splicing isoforms. By comparing translating mRNAs with steady-state overall transcripts, we found evidence for widespread post-transcriptional regulation at both the intron splicing and translational stages. Sequence analyses identified structural features associated with each step. Finally, we identified a new class of noncoding RNAs associated with polysomes. Findings from our profiling lead to new hypotheses in the understanding of flower development

    \u3ci\u3ePerfect 10 v. Visa\u3c/i\u3e: The Future of Contributory Copyright Infringement

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    End-of-life care in the United States: policy issues and model programs of integrated care

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    BACKGROUND: End-of-life care financing and delivery in the United States is fragmented and uncoordinated, with little integration of acute and long-term care services. OBJECTIVE: To assess policy issues involving end-of-life care, especially involving the hospice benefit, and to analyse model programs of integrated care for people who are dying. METHODS: The study conducted structured interviews with stakeholders and experts in end-of-life care and with administrators of model programs in the United States, which were nominated by the experts. RESULTS: The two major public insurance programs—Medicare and Medicaid—finance the vast majority of end-of-life care. Both programs offer a hospice benefit, which has several shortcomings, including requiring physicians to make a prognosis of a six month life expectancy and insisting that patients give up curative treatment—two steps which are difficult for doctors and patients to make—and payment levels that may be too low. In addition, quality of care initiatives for nursing homes and hospice sometimes conflict. Four innovative health systems have overcome these barriers to provide palliative services to beneficiaries in their last year of life. Three of these health systems are managed care plans which receive capitated payments. These providers integrate health, long-term and palliative care using an interdisciplinary team approach to management of services. The fourth provider is a hospice that provides palliative services to beneficiaries of all ages, including those who have not elected hospice care. CONCLUSIONS: End-of-life care is deficient in the United States. Public payers could use their market power to improve care through a number of strategies

    Enduring Legacy? Charles Tilly and Durable Inequality

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    This article assesses Charles Tilly’s Durable Inequality and traces its influence. In writing Durable Inequality, Tilly sought to shift the research agenda of stratification scholars. But the book’s initial impact was disappointing. In recent years, however, its influence has grown, suggesting a more enduring legacy

    Thermodynamics of Heat Shock Response

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    Production of heat shock proteins are induced when a living cell is exposed to a rise in temperature. The heat shock response of protein DnaK synthesis in E.coli for temperature shifts from temperature T to T plus 7 degrees, respectively to T minus 7 degrees is measured as function of the initial temperature T. We observe a reversed heat shock at low T. The magnitude of the shock increases when one increase the distance to the temperature T023oT_0 \approx 23^o, thereby mimicking the non monotous stability of proteins at low temperature. Further we found that the variation of the heat shock with T quantitatively follows the thermodynamic stability of proteins with temperature. This suggest that stability related to hot as well as cold unfolding of proteins is directly implemented in the biological control of protein folding. We demonstrate that such an implementation is possible in a minimalistic chemical network.Comment: To be published in Physical Review Letter

    Hypo-osmotic cell swelling activates the p38 MAP kinase signalling cascade

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    Hypo-osmotic swelling of human Intestine 407 cells leads to a significant increase of intracellular MAPKAP-kinase 2 activity and Hsp27 phosphorylation. Pre-treatment of the cells with the p38 MAP kinase inhibitor SB-203580 blocks this activation, indicating that the hypotonicity-induced activation of MAPKAP kinase 2 is, similarly to that described for hyperosmotic treatment, the result of an activated p38 MAP kinase cascade. The activation of MAPKAP kinase 2 proceeds with kinetics similar to that of one of the first physiological responses of hypo-osmotic treatment, the opening of compensatory Cl- channels. However, inhibition of the p38 MAP kinase cascade does not block the osmo-sensitive anion efflux and, vice versa, activation of p38 MAP kinase by cytokines and anisomycin does not increase the efflux. These results indicate that the p38 MAP kinase cascade is not directly involved in Cl- channel activation but instead may play a role in subsequent cellular repair processes

    Understanding governmental activism

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    This article seeks to understand an understudied phenomenon: governmental players joining forces with non-governmental players in contentious actions against policies they want to prevent or redress. This behaviour, which we call ‘governmental activism’, problematizes important assumptions in the social movement literature on state–SMO dichotomies and on seeing ‘the state’ as a homogeneous and unified actor that solely provides the context for SMO activities. Governmental activism also problematizes assumptions on cooperation and ‘new’ modes of coordination in the governance literature. To understand governmental activism, we build on the strategic interaction perspective from social movement studies and on third-phase institutionalism from political science. In our analysis, we show the particulars of governmental activism. Our arguments are illustrated by empirical material on a case of municipal amalgamation in the Netherlands
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