962 research outputs found

    The Second Transmembrane Domain of P2X7 Contributes to Dilated Pore Formation

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    Activation of the purinergic receptor P2X7 leads to the cellular permeability of low molecular weight cations. To determine which domains of P2X7 are necessary for this permeability, we exchanged either the C-terminus or portions of the second transmembrane domain (TM2) with those in P2X1 or P2X4. Replacement of the C-terminus of P2X7 with either P2X1 or P2X4 prevented surface expression of the chimeric receptor. Similarly, chimeric P2X7 containing TM2 from P2X1 or P2X4 had reduced surface expression and no permeability to cationic dyes. Exchanging the N-terminal 10 residues or C-terminal 14 residues of the P2X7 TM2 with the corresponding region of P2X1 TM2 partially restored surface expression and limited pore permeability. To further probe TM2 structure, we replaced single residues in P2X7 TM2 with those in P2X1 or P2X4. We identified multiple substitutions that drastically changed pore permeability without altering surface expression. Three substitutions (Q332P, Y336T, and Y343L) individually reduced pore formation as indicated by decreased dye uptake and also reduced membrane blebbing in response to ATP exposure. Three others substitutions, V335T, S342G, and S342A each enhanced dye uptake, membrane blebbing and cell death. Our results demonstrate a critical role for the TM2 domain of P2X7 in receptor function, and provide a structural basis for differences between purinergic receptors. © 2013 Sun et al

    Physical Stress, Not Biotic Interactions, Preclude an Invasive Grass from Establishing in Forb-Dominated Salt Marshes

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    Biological invasions have become the focus of considerable concern and ecological research, yet the relative importance of abiotic and biotic factors in controlling the invasibility of habitats to exotic species is not well understood. Spartina species are highly invasive plants in coastal wetlands; however, studies on the factors that control the success or failure of Spartina invasions across multiple habitat types are rare and inconclusive.We examined the roles of physical stress and plant interactions in mediating the establishment of the smooth cordgrass, Spartina alterniflora, in a variety of coastal habitats in northern China. Field transplant experiments showed that cordgrass can invade mudflats and low estuarine marshes with low salinity and frequent flooding, but cannot survive in salt marshes and high estuarine marshes with hypersaline soils and infrequent flooding. The dominant native plant Suaeda salsa had neither competitive nor facilitative effects on cordgrass. A common garden experiment revealed that cordgrass performed significantly better when flooded every other day than when flooded weekly. These results suggest that physical stress rather than plant interactions limits cordgrass invasions in northern China.We conclude that Spartina invasions are likely to be constrained to tidal flats and low estuarine marshes in the Yellow River Delta. Due to harsh physical conditions, salt marshes and high estuarine marshes are unlikely to be invaded. These findings have implications for understanding Spartina invasions in northern China and on other coasts with similar biotic and abiotic environments

    Ribosomal oxygenases are structurally conserved from prokaryotes to humans

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    2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases

    Сельскохозяйственная кооперация Урала за 1926-27 хозяйственный год и за I квартал 1927-28 г.: материалы к III собранию уполномоченных Уралселькустсоюза

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    0|7|Общие условия и итоги работы с.-х. кооперации за отчетный период [c. 7]0|11|Направление и темп кооперирования [c. 11]0|13|Союзное строительство [c. 13]0|13|Социальный состав пайщиков и его регулирование [c. 13]0|16|Итоги перевыборной кампании [c. 16]0|17|Аппарат системы [c. 17]0|18|Направление и характер организационной работы системы [c. 18]0|19|Культработа [c. 19]0|20|Массовая работа [c. 20]0|20|Колхозное строительство [c. 20]0|22|Кредитная работа [c. 22]0|26|Торгово-посредническая деятельность [c. 26]0|30|Финансы [c. 30]0|33|Производственная деятельность [c. 33]0|34|Агрикультурная работа [c. 34]0|35|Кустарно-промысловая кооперация в системе сел.-хоз. кооперации [c. 35]0|38|Состояние и работа системы в I кв. 1927-28 г. [c. 38]0|39|Рост колхозного движения [c. 39]0|40|Товарооборот с.-х. кооперации [c. 40]0|41|Финансовое состояние системы [c. 41]0|41|Итоги и перспективы [c. 41]0|45|Таблицы [c. 45]1|45|Сельско-хозяйственная кооперация в 1926-28 году [c. 45]2|45|Организационное состояние [c. 45]3|46|Сеть кооперативов в районах деятельности союзов сельско-хоз. и куст. пром. кооперации Уралобласти по видам [c. 46]3|47|Число всех кооперативов и членов в них в районах деятельности отдельных союзов сел.-хоз. и куст.-пром. кооперации и процент кооперированности хозяйств по округам [c. 47]3|49|Социально-имущественный состав членов-пайщиков сел.-хоз. кредитных товариществ на 1 октября 1927 года [c. 49]3|50|Состав правлений и ревкомиссий низовой сети сельско-хозяйственной кооперации до и после перевыборов 1927-28 г. [c. 50]2|51|Финансовое состояние [c. 51]3|52|Сводные балансы по отдельным видам сельско-хозяйственных кооперативов на 1-Х-1926 г. и 1-Х-1927 г. [c. 52]3|53|Сводные балансы сельско-хозяйственных кредитных товариществ на 1 октября 1927 года по союзам [c. 53]3|54|Балансы (нетто) союзов сел.-хоз. куст.-пром. кооперации на 1 октября 26 г. и на 1 октября 27 г. [c. 54]3|56|Балансы Уралселькустсоюза на 1-Х-1926 г. и 1-Х-1927 года [c. 56]3|57|Использование фондов кооперирования бедноты в 1926-27 г. и создание таковых из прибылей 1926-27 г. по низовой сети [c. 57]2|59|Хозяйственная работа и ее результаты [c. 59]3|61|Оброт по продаже товаров отдельных звеньев сельско-хозяйственной кооперации по сортиментным группам за 1926-27 год [c. 61]3|62|Распределение торговых оборотов сель.-хоз, кредитных товариществ по контрагентам в 1926-27 г. [c. 62]3|63|Общеторговые расходы сел.-хоз. кредитных товариществ за 1926-27 год [c. 63]3|64|Доходы сельско-хозяйственных кредитных товариществ за 1926-1927 год [c. 64]3|65|Агрономические предприятия низовой сети сель.-хоз кооперации на 1-Х 1927 год [c. 65]3|66|Промышленные предприятия низовой сети сельско-хозяйственной кооперации на 1-Х-1927 г. [c. 66]3|67|Товарооборот союзов сельско-хозяйственной и кустарно-промысловой кооперации за 1926-27 год [c. 67]3|68|Покупка и продажа товаров по снабжению союзами с.-х. куст. промысл. кооперации с разбивкой на контрагентов в 1926-27 г. [c. 68]3|69|Покупка и продажа товаров по сбыту союзами сел.-хоз. куст. пром. кооперации с разбивкой на контрагентов в 1926-27 году [c. 69]3|70|Доходы и обще-торговые расходы союзов сел.-хоз. и куст.-пром. кооперации в 1926-1927 году [c. 70]3|71|Наложение на себестоимость товаров в 1927-28 году [c. 71]2|72|Сельско-хозяйственная кооперация в I квартале 1927-28 года [c. 72]3|73|Сеть кооперативов в районе деятельности окружных и районных союзов, входящих в систему областного союза сел.-хоз. кооперации на 1-Х-27 г. и 1-I-1928 г. [c. 73]3|74|Число всех кооперативов и членов в них по отдельным союзам и процент кооперированости хозяйств по округам [c. 74]3|75|Сводные балансы с.-хоз. кредитных товариществ на 1 октября 27 г. и 1 января 1928 г. [c. 75]3|76|Сводные балансы (нетто) 1-ти окружных и районных союзов сел.-хоз. кооперации на 1-Х-27 и 1-I -28 г. [c. 76]3|78|Балансы (нетто) Уралселькустсоюза на 1/I-27 г., 1/I-28 г. и 1-IV-28 г. [c. 78]3|80|Оборот по продаже товаров союзов сельско-хозяйственной кооперации за I кварта 1927-28 года [c. 80]3|81|Обще-торговые расходы союзов сел.-хоз. кооперации в I квартале 1927-28 года [c. 81]3|82|Товарооборот и обще-торговые расходы союзов сел.-хоз. кооперации [c. 82]2|83|Текущие кампании [c. 83]3|84|Паевая кампания [c. 84]3|85|Перевыборная кампания 1927-28 г. [c. 85]3|85|Общие перевыборные собрания членов пайщиков сел.-хоз. кооперации в 1927-1928 году [c. 85]3|86|Перевыборные собрания уполномоченных сельско-хозяйственных к-вово в 1917-28 году [c. 86]0|87|Пояснения к таблицам [c. 87]0|90|Оглавление [c. 90

    Socio-cognitive determinants of consumers’ support for the fair trade movement

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    Despite the reasonable explanatory power of existing models of consumers’ ethical decision making, a large part of the process remains unexplained. This article draws on previous research and proposes an integrated model that includes measures of the theory of planned behavior, personal norms, self-identity, neutralization, past experience, and attitudinal ambivalence. We postulate and test a variety of direct and moderating effects in the context of a large survey with a representative sample of the U.K. population. Overall, the resulting model represents an empirically robust and holistic attempt to identify the most important determinants of consumers’ support for the fair-trade movement. Implications and avenues for further research are discussed

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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