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91.
Joan Vergés Gifra 《Ethnic and racial studies》2013,36(2):204-221
AbstractWhat kind of arguments can be used to justify a coercive language policy favouring the language of a cultural minority over the majority language of a state? To answer this question we will focus mainly on the language policy of the Catalan government and, to a lesser extent, on the language policies of the Basque Country and Quebec. Our aim is to develop a typology of arguments and try to show that each argument resorts to a different reason for coercion and has both virtues and flaws. 相似文献
92.
The classic myelin basic protein (MBP) splice isoforms range in nominal molecular mass from 14 to 21.5 kDa, and arise from the gene in the oligodendrocyte lineage (Golli) in maturing oligodendrocytes. The 18.5‐kDa isoform that predominates in adult myelin adheres the cytosolic surfaces of oligodendrocyte membranes together, and forms a two‐dimensional molecular sieve restricting protein diffusion into compact myelin. However, this protein has additional roles including cytoskeletal assembly and membrane extension, binding to SH3‐domains, participation in Fyn‐mediated signaling pathways, sequestration of phosphoinositides, and maintenance of calcium homeostasis. Of the diverse post‐translational modifications of this isoform, phosphorylation is the most dynamic, and modulates 18.5‐kDa MBP's protein‐membrane and protein‐protein interactions, indicative of a rich repertoire of functions. In developing and mature myelin, phosphorylation can result in microdomain or even nuclear targeting of the protein, supporting the conclusion that 18.5‐kDa MBP has significant roles beyond membrane adhesion. The full‐length, early‐developmental 21.5‐kDa splice isoform is predominantly karyophilic due to a non‐traditional P‐Y nuclear localization signal, with effects such as promotion of oligodendrocyte proliferation. We discuss in vitro and recent in vivo evidence for multifunctionality of these classic basic proteins of myelin, and argue for a systematic evaluation of the temporal and spatial distributions of these protein isoforms, and their modified variants, during oligodendrocyte differentiation. 相似文献
93.
HIV entry into the CNS is an early event after peripheral infection, resulting in neurologic dysfunction in a significant number of individuals despite successful anti‐retroviral therapy. The mechanisms by which HIV mediates CNS dysfunction are not well understood. Our group recently demonstrated that HIV infection of astrocytes results in survival of HIV infected cells and apoptosis of surrounding uninfected astrocytes by the transmission of toxic intracellular signals through gap junctions. In the current report, we characterize the intracellular signaling responsible for this bystander apoptosis. Here, we demonstrate that HIV infection of astrocytes results in release of cytochrome C from the mitochondria into the cytoplasm, and dysregulation of inositol trisphosphate/intracellular calcium that leads to toxicity to neighboring uninfected astrocytes. Blocking these dysregulated pathways results in protection from bystander apoptosis. These secondary messengers that are toxic in uninfected cells are not toxic in HIV infected cells, suggesting that HIV protects these cells from apoptosis. Thus, our data provide novel mechanisms of HIV mediated toxicity and generation of HIV reservoirs. Our findings provide new potential therapeutic targets to reduce the CNS damage resulting from HIV infection and to eradicate the generation of viral reservoirs.
94.
Joan W. Nowicke 《Grana》2013,52(1-3):51-77
Pollen of 190 species from 16 families has been examined by light and scanning electron microscopy. Three basic pollen types were found: 3-colpate, pantoporate, and pantocolpate, all with a spinulose and tubuliferous/punctate ektexine. The palynological data emphasize the close relationship of the betalain families, and support their association with the anthocyanin families. Caryophyllaceae and Molluginaceae. Pollen morphology reinforces the placement of the Cactaceae and Didiereaceae in the order, and would support the inclusion of Dysphania in the Chenopodiaceae. The pollen grains of the Achatocarpaceae, Bataceae, Gyrostemonaceae and Theligonaceae, none of which had the spinulose and tubuliferous/punctate ektexine, had no counterparts in the remaining taxa examined. Thus, the evidence from palynology does not support their inclusion in the Centrospermae and indicates that their placement should be re-examined. 相似文献
95.
Raymond van der Ham Gijs Grob Wilbert Hetterscheid Wim Star Bertie Joan van Heuven 《Grana》2013,52(4):252-265
A strict consensus tree based on chloroplast and nuclear sequences (rbcL, matK, trnL, FLint2) from 46 Amorphophallus species, two Pseudodracontium species and six outgroups is used to develop a hypothesis for the evolution of ornamentation and ectexine ultrastructure in the pollen of Amorphophallus. There are four main clades: an exclusively African, largely psilate clade (‘African clade’), an Asian, largely psilate clade (‘Asian psilate clade’) and an Asian, largely striate clade consisting of a mainly continental SE Asian clade (‘continental SE Asian striate clade’) and one centred in Malesia (‘Malesian striate clade’). Ultrastructure provides a valuable contribution towards understanding pollen ornamentation in Amorphophallus. Pollen with a thin psilate ectexine without dark granules might be plesiomorphic in Amorphophallus. Then the diverse striate type would be derived. Within both striate clades, reversals to the psilate type occur. Striate pollen with psilate caps, which is nested in the continental SE Asian striate clade, is a synapomorphy of Pseudodracontium. The fossulate type is also diverse, and its distribution in the tree indicates a polyphyletic origin. Areolate, echinate and verrucate ornamentation, occur in single species in the tree, but are found also in species not included in the molecular analysis. All three are heterogeneous and probably polyphyletic too. Reticulate, scabrate and striate/scabrate ornamentation are autapomorphies, of which the reticulate type and the striate/scabrate type may derive from psilate and striate ornamentation, respectively. Of the four main clades, the Asian psilate and African clade seem to be basal, while both striate clades might have evolved from the Asian psilate clade via a species like A. rhizomatosus. Dark granules evolved more than once, which might explain their diverse size, shape and distribution. 相似文献
96.
Anna M. Romaní Stefano Amalfitano Joan Artigas Stefano Fazi Sergi Sabater Xisca Timoner Irene Ylla Annamaria Zoppini 《Hydrobiologia》2013,719(1):43-58
River and stream biofilms in mediterranean fluvial ecosystems face both extreme seasonality as well as arrhythmic fluctuations. The hydrological extremes (droughts and floods) impose direct changes in water availability but also in the quantity and quality of organic matter and nutrients that sustain the microbial growth. This review analyzes how these ecological pulses might determine unique properties of biofilms developing in mediterranean streams. The paper brings together data from heterotrophic and autotrophic community structure, and extracellular enzyme activities in biofilms in mediterranean streams. Mediterranean stream biofilms show higher use of peptides during the favorable period for epilithic algae development (spring), and preferential use of cellulose and hemicellulose in autumn as a response to allochthonous input. The drying process causes the reduction in bacterial production and chlorophyll biomass, but the rapid recovery of both autotrophs and heterotrophs with rewetting indicates their adaptability to fluctuations. Bacteria surviving the drought are mainly associated with sediment and leaf litter which serve as “humid refuges”. Some algae and cyanobacteria show resistant strategies to cope with the drought stress. The resistance to these fluctuations is strongly linked to the streambed characteristics (e.g., sediment grain size, organic matter accumulation, nutrient content). 相似文献
97.
Yuxin Mao Yuxin Mao Leslie Mathewson Yuxin Mao Leslie Mathewson Joan Gesmonde 《Molecular membrane biology》2013,30(2):115-127
Residues Tyr-110 through Gly-115 of serotonin transporter were replaced, one at a time, with cysteine. Of these mutants, only G113C retained full activity for transport, Q111C and N112C retained partial activity, but Y110C, G114C and G115C were inactive. Poor surface expression was at least partly responsible for the lack of transport by G114C and G115C. In membrane preparations, Y110C through G113C all bound a high affinity cocaine analog similarly to the wild type. Treatment with methanethiosulfonate reagents increased the transport activity of Q111C and N112C to essentially wild-type levels but had no measurable effect on the other mutants. The decreased activity of Q111C and N112C resulted from an increase in the KM for serotonin that was not accompanied by a decrease in serotonin binding affinity. Superfusion experiments indicated a defect in 5-HT exchange. Modification of the inserted cysteine residues reversed the increase in KM and the poor exchange, also with no effect on serotonin affinity. The results suggest that Gln-111 and Asn-112 are not required for substrate binding but participate in subsequent steps in the transport cycle. 相似文献
98.
99.
Ann Lindstrand Joan Kalyango Tobias Alfvén Jessica Darenberg Daniel Kadobera Freddie Bwanga Stefan Peterson Birgitta Henriques-Normark Karin K?llander 《PloS one》2016,11(11)
BackgroundPneumonia is the major cause of death in children globally, with more than 900,000 deaths annually in children under five years of age. Streptococcus pneumoniae causes most deaths, most often in the form of community acquired pneumonia. Pneumococcal conjugate vaccines (PCVs) are currently being implemented in many low-income countries. PCVs decrease vaccine-type pneumococcal carriage, a prerequisite for invasive pneumococcal disease, and thereby affects pneumococcal disease and transmission. In Uganda, PCV was launched in 2014, but baseline data is lacking for pneumococcal serotypes in carriage.ObjectivesTo study pneumococcal nasopharyngeal carriage and serotype distribution in children under 5 years of age prior to PCV introduction in UgandaMethodsThree cross-sectional pneumococcal carriage surveys were conducted in 2008, 2009 and 2011, comprising respectively 150, 587 and 1024 randomly selected children aged less than five years from the Iganga/Mayuge Health and Demographic Surveillance Site. The caretakers were interviewed about illness history of the child and 1723 nasopharyngeal specimens were collected. From these, 927 isolates of S. pneumoniae were serotyped.ResultsOverall, the carriage rate of S. pneumoniae was 56% (957/1723). Pneumococcal carriage was associated with illness on the day of the interview (OR = 1.50, p = 0.04). The most common pneumococcal serotypes were in descending order 19F (16%), 23F (9%), 6A (8%), 29 (7%) and 6B (7%). One percent of the strains were non-typeable. The potential serotype coverage rate for PCV10 was 42% and 54% for PCV13.ConclusionAbout half of circulating pneumococcal serotypes in carriage in the Ugandan under-five population studied was covered by available PCVs. 相似文献
100.
Verónica García-Alonso Esther Titos Jose Alcaraz-Quiles Bibiana Rius Aritz Lopategi Cristina López-Vicario Per-Johan Jakobsson Salvadora Delgado Juanjo Lozano Joan Clària 《PloS one》2016,11(4)
Obesity induces white adipose tissue (WAT) dysfunction characterized by unremitting inflammation and fibrosis, impaired adaptive thermogenesis and increased lipolysis. Prostaglandins (PGs) are powerful lipid mediators that influence the homeostasis of several organs and tissues. The aim of the current study was to explore the regulatory actions of PGs in human omental WAT collected from obese patients undergoing laparoscopic bariatric surgery. In addition to adipocyte hypertrophy, obese WAT showed remarkable inflammation and total and pericellular fibrosis. In this tissue, a unique molecular signature characterized by altered expression of genes involved in inflammation, fibrosis and WAT browning was identified by microarray analysis. Targeted LC-MS/MS lipidomic analysis identified increased PGE2 levels in obese fat in the context of a remarkable COX-2 induction and in the absence of changes in the expression of terminal prostaglandin E synthases (i.e. mPGES-1, mPGES-2 and cPGES). IPA analysis established PGE2 as a common top regulator of the fibrogenic/inflammatory process present in this tissue. Exogenous addition of PGE2 significantly reduced the expression of fibrogenic genes in human WAT explants and significantly down-regulated Col1α1, Col1α2 and αSMA in differentiated 3T3 adipocytes exposed to TGF-β. In addition, PGE2 inhibited the expression of inflammatory genes (i.e. IL-6 and MCP-1) in WAT explants as well as in adipocytes challenged with LPS. PGE2 anti-inflammatory actions were confirmed by microarray analysis of human pre-adipocytes incubated with this prostanoid. Moreover, PGE2 induced expression of brown markers (UCP1 and PRDM16) in WAT and adipocytes, but not in pre-adipocytes, suggesting that PGE2 might induce the trans-differentiation of adipocytes towards beige/brite cells. Finally, PGE2 inhibited isoproterenol-induced adipocyte lipolysis. Taken together, these findings identify PGE2 as a regulator of the complex network of interactions driving uncontrolled inflammation and fibrosis and impaired adaptive thermogenesis and lipolysis in human obese visceral WAT. 相似文献