943 resultados para Formation of the theoretical conceptions
Resumo:
We have conducted a sensitive 3mm observation toward the shocked region, Lynds 1157 B1, which is an interaction spot between a molecular outflow and its ambient gas. We have successfully detected the CH3CHO, HCOOCH3, and HCOOH lines, as well as the CH2DOH line. The abundances of these molecules relative to CH3OH are found to be lower than those in the low-mass star-forming core, IRAS 16293-2422. Since these molecules are thought to evaporate from grain mantles, the observational results mean that complex molecules are less abundant in grain mantles residing in the ambient cloud surrounding a prestellar/protostellar core. Instead, efficient formation of the complex organic species and deuterated species should take place in a prestellar/protostellar core. The present result verifies the importance of an unbiased line survey of this source.
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In the present study of Dugesia tigrina the development of the nervous system is followed and compared during regeneration after fission and after decapitation. Immunocytochemistry was used, with antisera raised against the biogenic amine, 5-hydroxytryptamine (5-HT) and the two neuropeptides, neuropeptide F (NPF), and FMRF amide. The results indicate that two processes are involved in the formation of the new cerebral ganglion. First, new processes sprouting from the original main longitudinal nerve cords bend transversely, indicating the position of the developing horseshoe-shaped anterior cerebral commissure. Then new nerve cells in front of the commissure differentiate from neoblasts and their growth cones fasciculate with the fibres from the old main longitudinal nerve cords. In the cerebral ganglion, 5-HT-IR cells appear before NPF-IR cells, in contrast to the pharynx where NPF-IR cells differentiate before the 5-HT-IR cells. In the peripheral nervous system, NPF-IR fibres and cells appear at a very early stage and dominate the whole regeneration process. A role for the PNS in early pattern formation is suggested.
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The O7-specific lipopolysaccharide (LPS) in strains of Escherichia coli consists of a repeating unit made of galactose, mannose, rhamnose, 4-acetamido-2,6-dideoxyglucose, and N-acetylglucosamine. We have recently cloned and characterized genetically the O7-specific LPS biosynthesis region (rfbEcO7) of the E. coli O7:K1 strain VW187 (C. L. Marolda, J. Welsh, L. Dafoe, and M. A. Valvano, J. Bacteriol. 172:3590-3599, 1990). In this study, we localized the gnd gene encoding gluconate-6-phosphate dehydrogenase at one end of the rfbEcO7 gene cluster and sequenced that end of the cluster. Three open reading frames (ORF) encoding polypeptides of 275, 464, and 453 amino acids were identified upstream of gndEcO7, all transcribed toward the gnd gene. ORF275 had 45% similarity at the protein level with ORF16.5, which occupies a similar position in the Salmonella enterica LT2 rfb region, and presumably encodes a nucleotide sugar transferase. The polypeptides encoded by ORFs 464 and 453 were expressed under the control of the ptac promoter and visualized in Coomassie blue-stained sodium dodecyl sulfate-polyacrylamide gels and by maxicell analysis. ORF464 expressed GDP-mannose pyrophosphorylase and ORF453 encoded a phosphomannomutase, the enzymes for the biosynthesis pathway of GDP-mannose, one of the nucleotide sugar precursors for the formation of the O7 repeating unit. They were designated rfbMEcO7 and rfbKEcO7, respectively. The RfbMEcO7 polypeptide was homologous to the corresponding protein in S. enterica LT2, XanB of Xanthomonas campestris, and AlgA of Pseudomonas aeruginosa, all GDP-mannose pyrophosphorylases. RfbKEcO7 was very similar to CpsG of S. enterica LT2, an enzyme presumably involved in the biosynthesis of the capsular polysaccharide colanic acid, but quite different from the corresponding RfbK protein of S. enterica LT2.
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Research Question: A20 is an LPS-inducible, cytoplasmic zinc finger protein, that inhibits TLR-activated NF-?B signalling by deubiquitinating TRAF6. A20 action is facilitated by complex formation with RNF11, Itch and TAX1BP1. This study investigates if the expression of A20 is altered in the chronically inflamed Cystic Fibrosis (CF) airway epithelium.
Methods: Nasal epithelial cells from CF patients (F508del homozygous), non-CF controls and immortalised epithelial cells (16HBE14o- and CFBE41o-) were stimulated with LPS. Cytoplasmic expression of A20 and expression of NF-?B subunits was analysed. Formation of the A20 ubiquitin editing complex was also investigated.
Results: In CFBE41o-, peak LPS-induced A20 expression was delayed compared with 16HBE14o- and fell significantly below basal levels 12-24 h after LPS stimulation. This was confirmed in primary CF airway cells. Additionally, a significant inverse relationship between A20 and p65 expression was observed. Inhibitor studies showed that A20 does not undergo proteasomal degradation in CFBE41o-. A20 interacted with TAX1BP1, RNF11 and TRAF6 in 16HBE14o- cells, but these interactions were not observed in CFBE41o-.
Conclusion: he expression of A20 is significantly altered in CF and important interactions with complex members and target proteins are lost, which may contribute to the state of chronic NF-?B-driven inflammation.
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Trichinella spiralis is an intracellular nematode parasite of mammalian skeletal muscle. Infection of the muscle cell leads to the formation of a host-parasite complex that results in profound alterations to the host cell and a re-alignment of muscle-specific gene expression. The role of parasite excretory-secretory (ES) proteins in mediating these effects is currently unknown, largely due to the difficulty in identifying and assigning function to individual proteins. In this study, a global proteomics approach was used to analyse the ES proteins from T. spiralis muscle larvae. Following 2-DE of ES proteins,MALDI-TOF-MS and LC-MS/MS were used to identify the peptide spots. Specific Trichinella EST databases were assembled and used to analyse the data. Despite the current absence of a Trichinella genome-sequencing project, 43 out of 52 protein spots analysed were identified and included the major secreted glycoproteins. Other novel proteins were identified from matches with sequences in the T. spiralis database. Our results demonstrate the value of proteomics as a tool for the identification of Trichinella ES proteins and in the study of the molecular mechanism underpinning the formation of the host-parasite complex during Trichinella infections.
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Cell and tissue patterning in plant embryo development is well documented. Moreover, it has recently been shown that successful embryogenesis is reliant on programmed cell death (PCD). The cytoskeleton governs cell morphogenesis. However, surprisingly little is known about the role of the cytoskeleton in plant embryogenesis and associated PCD. We have used the gymnosperm, Picea abies , somatic embryogenesis model system to address this question. Formation of the apical-basal embryonic pattern in P. abies proceeds through the establishment of three major cell types: the meristematic cells of the embryonal mass on one pole and the terminally differentiated suspensor cells on the other, separated by the embryonal tube cells. The organisation of microtubules and F-actin changes successively from the embryonal mass towards the distal end of the embryo suspensor. The microtubule arrays appear normal in the embryonal mass cells, but the microtubule network is partially disorganised in the embryonal tube cells and the microtubules disrupted in the suspensor cells. In the same embryos, the microtubule-associated protein, MAP-65, is bound only to organised microtubules. In contrast, in a developmentally arrested cell line, which is incapable of normal embryonic pattern formation, MAP-65 does not bind the cortical microtubules and we suggest that this is a criterion for proembryogenic masses (PEMs) to passage into early embryogeny. In embryos, the organisation of F-actin gradually changes from a fine network in the embryonal mass cells to thick cables in the suspensor cells in which the microtubule network is completely degraded. F-actin de-polymerisation drugs abolish normal embryonic pattern formation and associated PCD in the suspensor, strongly suggesting that the actin network is vital in this PCD pathway.
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Background:
Healthcare in Qatar is undergoing a period of major reform, driven by a strong economy and vision for a world-class healthcare system. One area identified as a potential contributor to developing a world-class healthcare system is interprofessional education (IPE), with the goal of facilitating healthcare workers to work together collaboratively. Several key steps have been taken towards developing IPE in Qatar, such as the formation of the Qatar Interprofessional Health Council (QIHC), the development of an IPE program for undergraduate healthcare students, the development of a set of shared core competencies, the receipt of substantial buy-in from leaders across the healthcare system, and recent approval of funding to develop a post-licensure healthcare IPE program. In order to improve IPE in Qatar, it is important to better understand the facilitators and barriers to interprofessional collaboration in Qatar. This study seeks to do so by qualitatively exploring facilitators and barriers to interprofessional collaboration for healthcare professional in Qatar from the perspective of health care professionals. By better understanding how health care workers give meaning to interprofessional education and collaboration, this research can assist in improving interprofessional activities in healthcare in Qatar.
Objectives
The purpose of this paper-presentation is to report on finding from a qualitative study that explored different facilitators and barriers of interprofessional practice in Qatar.
Method:
Ten healthcare professionals who work in Qatar were interviewed using semi-structured, open-ended interviews. Interview questions were organized by phenomenological (e.g. exploring the lived-experiences of healthcare workers) and ethnographic interviewing techniques (e.g. focusing on what people do). The questions explored the barriers, facilitators, and what is working well in terms of interprofessional practice for health care professional in Qatar.
Findings and Implications:
Different factors associated with interprofessional collaborations will be discussed. In doing so, this research adds to the literature on IPE by shedding light on interprofessional collaboration and education in the Middle East. Furthermore, this study identifies barriers for health care workers to work collaboratively in health care settings in Qatar. Addressing such barriers, and building off of what is working well, will facilitate Qatar in reaching one of the Vision 2030 goals of improving Qatar’s health and wellness.
Resumo:
Background:
Healthcare in Qatar is undergoing a period of major reform, driven by a strong economy and vision for a world-class healthcare system. One area identified as a potential contributor to developing a world-class healthcare system is interprofessional education (IPE), with the goal of facilitating healthcare workers to work together collaboratively. Several key steps have been taken towards developing IPE in Qatar, such as the formation of the Qatar Interprofessional Health Council (QIHC), the development of an IPE program for undergraduate healthcare students, the development of a set of shared core competencies, the receipt of substantial buy-in from leaders across the healthcare system, and recent approval of funding to develop a post-licensure healthcare IPE program. In order to improve IPE in Qatar, it is important to better understand the facilitators and barriers to interprofessional collaboration in Qatar. This study seeks to do so by qualitatively exploring facilitators and barriers to interprofessional collaboration for healthcare professional in Qatar from the perspective of health care professionals. By better understanding how health care workers give meaning to interprofessional education and collaboration, this research can assist in improving interprofessional activities in healthcare in Qatar.
Objectives
The purpose of this paper-presentation is to report on finding from a qualitative study that explored different facilitators and barriers of interprofessional practice in Qatar.
Method:
Ten healthcare professionals who work in Qatar were interviewed using semi-structured, open-ended interviews. Interview questions were organized by phenomenological (e.g. exploring the lived-experiences of healthcare workers) and ethnographic interviewing techniques (e.g. focusing on what people do). The questions explored the barriers, facilitators, and what is working well in terms of interprofessional practice for health care professional in Qatar.
Findings and Implications:
Different factors associated with interprofessional collaborations will be discussed. In doing so, this research adds to the literature on IPE by shedding light on interprofessional collaboration and education in the Middle East. Furthermore, this study identifies barriers for health care workers to work collaboratively in health care settings in Qatar. Addressing such barriers, and building off of what is working well, will facilitate Qatar in reaching one of the Vision 2030 goals of improving Qatar’s health and wellness.
Resumo:
Patterns of glycosylation are important in cancer, but the molecular mechanisms that drive changes are often poorly understood. The androgen receptor drives prostate cancer (PCa) development and progression to lethal metastatic castration-resistant disease. Here we used RNA-Seq coupled with bioinformatic analyses of androgen-receptor (AR) binding sites and clinical PCa expression array data to identify ST6GalNAc1 as a direct and rapidly activated target gene of the AR in PCa cells. ST6GalNAc1 encodes a sialytransferase that catalyses formation of the cancer-associated sialyl-Tn antigen (sTn), which we find is also induced by androgen exposure. Androgens induce expression of a novel splice variant of the ST6GalNAc1 protein in PCa cells. This splice variant encodes a shorter protein isoform that is still fully functional as a sialyltransferase and able to induce expression of the sTn-antigen. Surprisingly, given its high expression in tumours, stable expression of ST6GalNAc1 in PCa cells reduced formation of stable tumours in mice, reduced cell adhesion and induced a switch towards a more mesenchymal-like cell phenotype in vitro. ST6GalNAc1 has a dynamic expression pattern in clinical datasets, beingsignificantly up-regulated in primary prostate carcinoma but relatively down-regulated in established metastatic tissue. ST6GalNAc1 is frequently upregulated concurrently with another important glycosylation enzyme GCNT1 previously associated with prostate cancer progression and implicated in Sialyl Lewis X antigen synthesis. Together our data establishes an androgen-dependent mechanism for sTn antigen expression in PCa, and are consistent with a general role for the androgen receptor in driving important coordinate changes to the glycoproteome during PCa progression.
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INTRODUCTION AND GOALS: Genus Bursaphelenchus includes several pests of the world importance for the rural economy, the most dangerous are the Bursaphelenchus xylophilus (the pinewood nematode caused decline of the pine trees in south Asia and in one spot area in Europe, Portugal, Peninsula de Setubal) and the Bursaphelenchus cocophilus, causing the decline of coco-palm plantations in Carribean and Latin American regions. The peculiarity of the host-parasite association of the genus that the nematode life cycle includes three trophic components: plant (mostly a tree), insect vector and a fungus. Goals of the presentation is to list all species of the world fauna and all efficient diagnostic characters, then create the identification tool and analyze the similarity of species and possible ways and causes of the host-parasite evolution of the group. RESULTS: Complete list of species with synonymy and a catalogue of all efficient diagnostic characters with their states, selected from papers of the most experienced taxonomists of the genus, are given for the genus Bursaphelenchus. List of known records of Bursaphelenchus species with names of natural vectors and plants and their families is given (for world pests the most important groups of trees and insects are listed). The tabular, traditional and computer-aided keys are presented. Dendrograms of species relationships (UPGMA, standard distance: mean character difference) based on all efficient taxonomic characters and separately on the spicule characters only, are given. Discussion whether the species groups are natural or purely diagnostic ones is based on the relationships dendrograms and the vector and associated plant ranges of Bursaphelenchus species; the xylophilus species group (B. xylophilus, B. abruptus, B. baujardi, B. conicaudatus, B. eroshenkii, B. fraudulentus, B. kolymensis, B. luxuriosae; B. mucronatus), the hunti group (B. hunti, B. seani, B. kevini and B. fungivorus) are probably the natural ones. CONCLUSIONS: The parasitic nematode association includes three trophic components: plant, insect vector and fungus. The initial insect-plant complex Scolytidae-Pinaceae is changeable and only in rare occasions the change of the preferred vector to Cerambycidae (the xylophilus group), Hymenoptera (the hunti group) led to formation of the natural species-groups. From the analysis it is clear that although the vector range is changeable it is comparatively more important for the evolution of the genus Bursaphelenchus than associations with plants at the family level. Data on the fungi species (3rd component in natural Bursaphelenchus associations) are insufficient for the detailed comparative analysis.
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This research is a study of modern developments of the institutions of the Nizārī Ismaili imamate during the time of the present Ismaili Imam, Shāh Karīm al-Ḥusaynī, Aga Khan IV, as the 49th hereditary living Imam of Shiʿi Nizārī Ismaili Muslims, particularly addressing the formation of the Aga Khan Development Network (AKDN) and the functions of the Community institutions. Using the case study of the Aga Khan Development Network and the Nizārī Ismaili imamate, this research demonstrates that the three ideal types of authority as proposed by Weber, namely the traditional, charismatic and legal-bureaucratic types, are not sufficient to explain the dynamics of authority among Muslims. This is partly due to Weber’s belief in the uniqueness of Western civilisation, which is a product of his thesis on Protestant Ethics and partly because his ideal typical system does not work in the case of the Muslim societies. The Ismaili imamate with its multifarious institutions in contemporary times is the most suitable counter-example by which to powerfully demonstrate that Weberian models of authority fail to explain this phenomenon and it would indeed appear as a paradoxical institution if viewed with Weberian theses. The Ismaili imamate in contemporary times represents a paradigm shift and a transmutation not only as regards the Weberian models but also when viewed from inside the tradition of Shiʿi Muslim history. This evolutionary leap forward, which has been crystallised over the course of the past half a century, in the Ismaili imamate suggests the development of a new form of authority which is unprecedented. There are clearly various elements in this form of authority which could be discerned as rooted in tradition and history; however the distinctive elements of this new form of authority give it a defining and exciting dimension. There are several qualities which are peculiar to the contemporary condition of the Ismaili imamate and its style of leadership which are distinctive. Most importantly, while some central features, like succession by way of designation (naṣṣ) has not changed, there is one overarching quality which can best capture all these elements and that is the transmutation of the Ismaili imamate from the person of the Imam into the office of imamate and thus we are now facing the institutionalisation of the imamate and the office being the embodiment of the authority of the Imam. I have described this new development as a metamorphosis of the authority because it gives an entirely new form and content to the previously familiar concept of authority in the Shiʿi Ismaili Muslim tradition.
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This thesis analyses how dominant policy approaches to peacebuilding have moved away from a single and universalised understanding of peace to be achieved through a top-down strategy of democratisation and economic liberalisation, prevalent at the beginning of 1990s. Instead, throughout the 2000s, peacebuilders have increasingly adopted a commitment to cultivating a bottom-up and hybrid peace building process that is context-sensitive and intended to be more respectful of the needs and values of post-war societies. The projects of statebuilding in Kosovo and, to a lesser extent, in Bosnia are examined to illustrate the shift. By capturing this shift, I seek to argue that contemporary practitioners of peace are sharing the sensibility of the theoretical critics of liberalism. These critics have long contended that post-war societies cannot be governed from ‘above’ and have advocated the adoption of a bottom-up approach to peacebuilding. Now, both peace practitioners and their critics share the tendency to embrace difference in peacebuilding operations, but this shift has failed to address meaningfully the problems and concerns of post-conflict societies. The conclusion of this research is that, drawing on the assumption that these societies are not capable of undertaking sovereign acts because of their problematic inter-subjective frames, the discourses of peacebuilding (in policy-making and academic critique) have increasingly legitimised an open-ended role of interference by external agencies, which now operate from ‘below’. Peacebuilding has turned into a long-term process, in which international and local actors engage relationally in the search for ever-more emancipatory hybrid outcomes, but in which self-government and self-determination are constantly deferred. Processes of emphasising difference have thus denied the political autonomy of post-war societies and have continuously questioned the political and human equality of these populations in a hierarchically divided world.
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Endospores, or spores for simplicity, are a highly resistant cell type produced by some bacterial species under adverse conditions. Two main protective layers contribute to the resilience of spores: the cortex, composed of peptidoglycan, and the outermost proteinaceous coat. In Bacillus subtilis, the coat comprises up to 80 different proteins, organized into four sublayers: the basement layer, the inner coat, the outer coat and the crust. These proteins are synthesized at different times during sporulation and deposited at the spore surface in multiple coordinated waves. Central to coat formation is a group of morphogenetic proteins that guide the assembly of the coat components. Targeting of the coat proteins to the surface of the developing spore is mainly controlled by the SpoIVA morphogenetic ATPase. In a second stage, the coat proteins fully encircle the spore, a process termed encasement that requires the morphogenetic protein SpoVID. Assembly of the inner coat requires SafA, whereas formation of the outer coat and the crust requires CotE. SafA interacts directly with the N terminus of SpoVID. (...)
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Na,K-ATPase is the main active transport system that maintains the large gradients of Na(+) and K(+) across the plasma membrane of animal cells. The crystal structure of a K(+)-occluding conformation of this protein has been recently published, but the movements of its different domains allowing for the cation pumping mechanism are not yet known. The structure of many more conformations is known for the related calcium ATPase SERCA, but the reliability of homology modeling is poor for several domains with low sequence identity, in particular the extracellular loops. To better define the structure of the large fourth extracellular loop between the seventh and eighth transmembrane segments of the alpha subunit, we have studied the formation of a disulfide bond between pairs of cysteine residues introduced by site-directed mutagenesis in the second and the fourth extracellular loop. We found a specific pair of cysteine positions (Y308C and D884C) for which extracellular treatment with an oxidizing agent inhibited the Na,K pump function, which could be rapidly restored by a reducing agent. The formation of the disulfide bond occurred preferentially under the E2-P conformation of Na,K-ATPase, in the absence of extracellular cations. Using recently published crystal structure and a distance constraint reproducing the existence of disulfide bond, we performed an extensive conformational space search using simulated annealing and showed that the Tyr(308) and Asp(884) residues can be in close proximity, and simultaneously, the SYGQ motif of the fourth extracellular loop, known to interact with the extracellular domain of the beta subunit, can be exposed to the exterior of the protein and can easily interact with the beta subunit.
Resumo:
The Pater metavolcanic suite (PVS) was extruded as part O'f the basal Pater Formation of the Huronian Supergroup ca. 2.4 Ga. They Ars classified as wi thin-plate tholeiites associated with an immature ri-fting episode, and are inter layered with associated vol cani clastic and metasedimentary units. Post-solidif ication alteration caused redistribution o-f the alkalies, Sr, Rb, Ba, Cu, and SiO^. Ce, Y, Zr, CFezOs (as total Fe), Al^Os, TiOa, and, PaOa are considered to have remained essentially immobile in least altered samples. Petrogenetic modelling indicates the PVS was derived from the partial melting of two geochemical ly similar sources in the sub-continental lithosphere. Fractionation was characterized by an oli vine-plagioclase assemblage and a sub-volcanic plagioclase-clinopyroxene assemblage. A comparative study indicates that enrichment of the postulated Huronian source cannot be reconciled by Archean contamination. Enrichment is thought to have been caused by hydrous veined metasomatic heterogeneities in the sub-continental lithosphere, generated by an Archean subduct ion event before 2.68 Ga.