281 research outputs found

    A carboxyl-terminal interaction of lamin B1 is dependent on the CAAX endoprotease Rce1 and carboxymethylation

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    The mammalian nuclear lamina protein lamin B1 is posttranslationally modified by farnesylation, endoproteolysis, and carboxymethylation at a carboxyl-terminal CAAX motif. In this work, we demonstrate that the CAAX endoprotease Rce1 is required for lamin B1 endoproteolysis, demonstrate an independent pool of proteolyzed but nonmethylated lamin B1, as well as fully processed lamin B1, in interphase nuclei, and show a role for methylation in the organization of lamin B1 into domains of the nuclear lamina. Deficiency in the endoproteolysis or methylation of lamin B1 results in loss of integrity and deformity of the nuclear lamina. These data show that the organization of the nuclear envelope and lamina is dependent on a mechanism involving the methylation of lamin B1, and they identify a potential mechanism of laminopathy involving a B-type lamin

    Temporal dynamics of aquatic communities and implications for pond conservation

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    Conservation through the protection of particular habitats is predicated on the assumption that the conservation value of those habitats is stable. We test this assumption for ponds by investigating temporal variation in macroinvertebrate and macrophyte communities over a 10-year period in northwest England. We surveyed 51 ponds in northern England in 1995/6 and again in 2006, identifying all macrophytes (167 species) and all macroinvertebrates (221 species, excluding Diptera) to species. The alpha-diversity, beta-diversity and conservation value of these ponds were compared between surveys. We find that invertebrate species richness increased from an average of 29. 5 species to 39. 8 species between surveys. Invertebrate gamma-diversity also increased between the two surveys from 181 species to 201 species. However, this increase in diversity was accompanied by a decrease in beta-diversity. Plant alpha-, beta and gamma-diversity remained approximately constant between the two periods. However, increased proportions of grass species and a complete loss of charophytes suggests that the communities are undergoing succession. Conservation value was not correlated between sampling periods in either plants or invertebrates. This was confirmed by comparing ponds that had been disturbed with those that had no history of disturbance to demonstrate that levels of correlation between surveys were approximately equal in each group of ponds. This study has three important conservation implications: (i) a pond with high diversity or high conservation value may not remain that way and so it is unwise to base pond conservation measures upon protecting currently-speciose habitats; (ii) maximising pond gamma-diversity requires a combination of late and early succession ponds, especially for invertebrates; and (iii) invertebrate and plant communities in ponds may require different management strategies if succession occurs at varying rates in the two groups

    Building professional discourse in emerging markets: Language, context and the challenge of sensemaking

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    Using ethnographic evidence from the former Soviet republics, this article examines a relatively new and mainly unobserved in the International Business (IB) literature phenomenon of communication disengagement that manifests itself in many emerging markets. We link it to the deficiencies of the local professional business discourse rooted in language limitations reflecting lack of experience with the market economy. This hampers cognitive coherence between foreign and local business entities, adding to the liability of foreignness as certain instances of professional experience fail to find adequate linguistic expression, and complicates cross-cultural adjustments causing multi-national companies (MNCs) financial losses. We contribute to the IB literature by examining cross-border semantic sensemaking through a retrospectively constructed observational study. We argue that a relative inadequacy of the national professional idiom is likely to remain a feature of business environment in post-communist economies for some time and therefore should be factored into business strategies of MNCs. Consequently, we recommend including discursive hazards in the risk evaluation of international projects

    Crisis and change in industrial relations in Central and Eastern Europe

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    This article introduces the special issue on industrial relations in Central and Eastern Europe since the financial and economic crisis. Already dependent economically on funding from the west, and lacking the robust industrial relations institutions traditional in much of Western Europe, countries in the region were particularly vulnerable. However, there are important cross-national differences, and the strategies of key actors have significantly affected the outcomes

    Effects of place attachment on home return travel: a spatial perspective

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    Recent studies on place-mobility relationships suggest an increasing possibility that people can have multiple place attachments at varied spatial scales. Yet our understanding of how place attachment in different spatial scales affects mobility remains limited. This study investigates home return visits by Chinese diaspora tourists from North America who have made multiple trips to China. A total of 27 in-depth interviews with repeat home return travellers was conducted. Four different types of return movements were identified: local; dispersed; local & dispersed; and second-migration locale focused. A relationship was found between the participants’ sense of place, place identity and home return travel. The findings suggest that home return travel is more complex than previously thought. More focused sense of place and strong personal connection to ancestral homes may lead to more localized return, while a more generic sense of place (i.e. to ‘China’) and collective personal identity would result in a more dispersed travel pattern. Family migration history and strong attachment to family’s first migration destination also leads to focused return to the place. The study highlights the fact that place and place attachment are deeply personal and can evolve over time and space

    Temperate zone plant natural products – a novel resource for activity against tropical parasitic diseases

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    The use of plant-derived natural products for the treatment of tropical parasitic diseases often has ethnopharmacological origins. As such, plants grown in temperate regions remain largely untested for novel anti-parasitic activities. We describe here a screen of the PhytoQuest Phytopure library, a novel source comprising over 600 purified compounds from temperate zone plants, against in vitro culture systems for Plasmodium falciparum, Leishmania mexicana, Trypanosoma evansi and T. brucei. Initial screen revealed 6, 65, 15 and 18 compounds, respectively, that decreased each parasite’s growth by at least 50% at 1-2µM concentration. These initial hits were validated in concentration-response assays against the parasite and the human HepG2 cell line, identifying hits with EC50 10. Two sesquiterpene glycosides were identified against P. falciparum, four sterols against L. mexicana, and five compounds of various scaffolds against T. brucei and T. evansi. An L. mexicana resistant line was generated for the sterol 700022, which was found to have cross-resistance to the anti-leishmanial drug miltefosine as well as to the other leishmanicidal sterols. This study highlights the potential of a temperate plant secondary metabolites as a novel source of natural products against tropical parasitic diseases

    Trophoblast organoids as a model for maternal-fetal interactions during human placentation.

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    The placenta is the extraembryonic organ that supports the fetus during intrauterine life. Although placental dysfunction results in major disorders of pregnancy with immediate and lifelong consequences for the mother and child, our knowledge of the human placenta is limited owing to a lack of functional experimental models1. After implantation, the trophectoderm of the blastocyst rapidly proliferates and generates the trophoblast, the unique cell type of the placenta. In vivo, proliferative villous cytotrophoblast cells differentiate into two main sub-populations: syncytiotrophoblast, the multinucleated epithelium of the villi responsible for nutrient exchange and hormone production, and extravillous trophoblast cells, which anchor the placenta to the maternal decidua and transform the maternal spiral arteries2. Here we describe the generation of long-term, genetically stable organoid cultures of trophoblast that can differentiate into both syncytiotrophoblast and extravillous trophoblast. We used human leukocyte antigen (HLA) typing to confirm that the organoids were derived from the fetus, and verified their identities against four trophoblast-specific criteria3. The cultures organize into villous-like structures, and we detected the secretion of placental-specific peptides and hormones, including human chorionic gonadotropin (hCG), growth differentiation factor 15 (GDF15) and pregnancy-specific glycoprotein (PSG) by mass spectrometry. The organoids also differentiate into HLA-G+ extravillous trophoblast cells, which vigorously invade in three-dimensional cultures. Analysis of the methylome reveals that the organoids closely resemble normal first trimester placentas. This organoid model will be transformative for studying human placental development and for investigating trophoblast interactions with the local and systemic maternal environment.Centre for Trophoblast Reearch Royal Society Dorothy Hodgkin Fellowship Marie Curie Intra-European Fellowshi
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