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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
401

Interaction plante-microorganismes : Implication de la rhizobactérie Phyllobacterium brassicacearum dans les réponses d’Arabidopsis thaliana au stress hydrique / Plant-microbes interactions : Implication of Phyllobacterium brassicacearum in Arabidopsis responses to water deficit

Bresson, Justine 16 December 2013 (has links)
Les bactéries promotrices de la croissance des plantes (PGPR) peuvent améliorer la performance et la tolérance des plantes lors de stress environnementaux. Arabidopsis thaliana est un modèle de choix pour étudier les mécanismes impliqués dans les interactions plante-bactéries. Nous avons analysé de multiples traits associés à la dynamique de croissance, au développement et la physiologie des végétaux afin d'évaluer les effets de l'inoculation par Phyllobacterium brassicacearum STM196, une PGPR isolée de la rhizosphère du colza, sur les réponses d'A. thaliana à des stress hydriques de différentes intensités. Grâce à des outils performants de phénotypage, nous avons développé une nouvelle approche d'analyse à haut-débit pour examiner l'implication de STM196 dans les stratégies de résistance des plantes au stress hydrique. Nos résultats montrent pour la première fois que les PGPR peuvent interférer dans les stratégies d'échappement des plantes grâce à des modifications de la croissance et du temps de floraison. De plus, STM196 induit une meilleure résistance au déficit hydrique modéré et une meilleure tolérance à la déshydratation sous une contrainte hydrique sévère. L'inoculation par STM196 peut ainsi représenter une valeur ajoutée aux stratégies de résistance intrinsèques aux plantes, ce qui est illustrée par sa remarquable capacité à promouvoir la survie et la production de biomasse végétale dans des environnements contrastés. Nos résultats soulignent l'importance des interactions plantes-bactéries dans les réponses des plantes à la sécheresse et offrent de nouvelles voies de recherches pour l'amélioration de la résistance à la sécheresse dans les cultures. / Plant growth promoting rhizobacteria (PGPR) can enhance plant performance and plant tolerance to environmental stresses. Arabidopsis thaliana is a useful organism to study the mechanisms involved in plant-PGPR interactions. We analyzed multiple plant traits related to growth dynamics, development and physiology in order to assess the effects of Phyllobacterium brassicacearum STM196 strain, isolated from the rhizosphere of oilseed rape, on Arabidopsis responses to well-defined soil water availability. Using powerful tools for phenotyping, we developed a new high-throughput analysis to examine the implication of STM196 on plant strategies to cope with water stress. Our results show for the first time that PGPR can interfere in escape strategies of plants through modifications in plant growth and flowering time. Moreover, STM196 induced a better resistance to moderate water deficit and a better tolerance to dehydration under a severe stress. Inoculation by STM196 can represent an added value to plant resistance strategies, as illustrated by its remarkable ability to promote plant survival and biomass production under contrasted environments. Our results highlight the importance of plant-bacteria interactions in plant responses to drought and provide a new avenue of investigations to improve drought resistance in crops.
402

Avaliação de parâmetros do metabolismo de carbono e nitrogênio e de respostas ao estresse na associação de trigo com a bactéria Herbaspirillum seropedicae / Evaluation of carbon and nitrogen metabolism parameters and responses to stress in wheat association with bacteria Herbaspirillum seropedicae

Ortolan, Sarah Romani 28 July 2015 (has links)
Made available in DSpace on 2017-07-10T17:37:10Z (GMT). No. of bitstreams: 1 Sarah_Romano_Ortolan.pdf: 975526 bytes, checksum: d72ab61fc7bdc88b6ddbab0eb3a86e42 (MD5) Previous issue date: 2015-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Wheat is considered the main cereal diet of the world population, but in recent years has achieved some gain in productivity of this culture despite having increased the use of nitrogen fertilizer. The use of plant growth promoting bacteria such as Herbaspirillum seropedicae SmR1 among others has been studied to obtain development of plants with less use of nitrogen fertilizers. However there is little information relating the effects of this interaction in plant development and grain yield. Objective of this study was to evaluate the carbon and nitrogen metabolism by certain enzymes, metabolites and indices related to the response to infectious stress on the wheat cultivars CD 104 and CD 120 in association with Herbaspirillum seropedicae bacteria. Two experiments were conducted. The experimental design was completely randomized with four replications in a 4x2. The first factor relates to the conditions inoculation with bacteria and/or nitrogen source in coverage are: control without inoculation with bacteria or added nitrogen fertilizer (C); application of nitrogen fertilizer (50 kg.ha-1) 30 days after sowing (N); inoculation with 106 cells of the bacterium H. seropedicae/seed at planting (Hs) and inoculation with bacteria combined with the application of nitrogen fertilizer (Hs + N) and the second factor refers to the phenological stages (tillering and booting). The results indicated that inoculation with H. seropedicae in wheat seeds of cv.s CD 104 and CD 120 in the two growth stages answered in relation to the indices related to stress with the involvement of enzymes of carbon and nitrogen metabolism. However prominent effect was not noticed to promote plant growth of wheat in late development, nor a deleterious effect of the bacterium for inoculation cv. CD 104 under the experimental conditions. For cv. CD 120 the differential effects indicate lower levels of stress and some level of association to positive effect on productivity when combined inoculation of bacteria to nitrogen fertilization. It was concluded that as well as pathogenic and stressors, H. seropedicae able to beneficially associate with wheat also provides similar interference pattern of carbon and nitrogen metabolism and stress levels / O trigo é considerado o principal cereal da dieta da população mundial, entretanto nos últimos anos tem se obtido pouco ganho de produtividade desta cultura apesar de se ter aumentado o uso de fertilizante nitrogenado. O uso de bactérias promotoras do crescimento vegetal, como Herbaspirillum seropedicae SmR1 entre outras, tem sido estudado para se obter desenvolvimento de plantas com menor uso de fertilizantes nitrogenados. Entretanto existem poucas informações que relacionam os efeitos desta interação no desenvolvimento da planta e de produtividade de grãos. Objetivo deste trabalho foi avaliar o metabolismo de carbono e nitrogênio através de algumas enzimas, metabólitos e índices relacionados à resposta ao estresse infeccioso em trigo das cultivares CD 104 e CD 120 em associação com a bactéria Herbaspirillum seropedicae em dois estádios fenológicos. Foram realizados dois experimentos. O delineamento experimental utilizado foi o inteiramente ao acaso, com 4 repetições, em esquema fatorial 4x2. O primeiro fator refere-se às condições de inoculação com bactéria e/ou fertilização nitrogenada em cobertura, sendo: controle, sem inoculação com bactéria ou adição de fertilizante nitrogenado (C); aplicação de fertilizante nitrogenado (50 kg.ha-1) após 30 dias da semeadura (N); inoculação de 106 células da bactéria H. seropedicae/semente na semeadura (Hs) e inoculação com a bactéria combinada com a aplicação de fertilizante nitrogenado (Hs + N) e o segundo fator refere-se aos estádios fenológicos (perfilhamento e emborrachamento). Os resultados indicaram que a inoculação com H. seropedicae em sementes de trigo das cv.s CD 104 e CD 120 nos dois estádios fenológicos responderam em relação aos índices relacionados ao estresse com envolvimento das enzimas do metabolismo de carbono e nitrogênio. Entretanto não foi percebido efeito proeminente de promoção do crescimento vegetal no final do desenvolvimento do trigo, tampouco efeito deletério da inoculação de bactéria para a cv. CD 104, nas condições experimentais. Para a cv. CD 120 os efeitos diferenciais indicam menor nível de estresse e algum nível de associação para efeito positivo na produtividade quando combinada a inoculação da bactéria com a fertilização nitrogenada. Foi possível concluir que assim como para agentes patogênicos e estressantes, a H. seropedicae, capaz de associar beneficamente com trigo também apresenta padrão semelhante de interferência do metabolismo de carbono e nitrogênio e índices de estresse
403

Identification and characterization of type III effector proteins in plant-associated bacteria

Thomas, William J. 04 May 2012 (has links)
Symbioses between microbes and multicellular eukaryotes are found in all biomes, and encompass a spectrum of symbiotic lifestyles that includes parasitism and disease, commensalism, and mutually beneficial interdependent host-microbe relationships. Regardless of outcome, these symbiotic lifestyles are governed by a complex molecular "courtship" between microbe and potential host. This courtship is the primary determinant of the host range of a given microsymbiont. Host immunity poses a formidable barrier to the establishment of host-microbe relationships, and the majority of microbial suitors will be thwarted by it. Only by successfully "wooing" the host cell's immune defenses with the appropriate molecular signals can a microsymbiont successfully colonize its host. A strategy common to microsymbionts across the spectrum of symbiotic lifestyles and host organisms is the delivery of microbial-encoded effector proteins into the cytoplasm of host cells to manipulate the host cell's molecular machinery for the purposes of subverting host immunity. Bacteria, in particular, have adapted a number of secretion systems for this purpose. The most well-characterized of these is the type III secretion system (T3SS), a molecular apparatus that specializes in injecting type III effector (T3Es) proteins directly into host cells. The work in this thesis focuses on T3Es of plant-associated bacteria, with particular emphasis on mutualistic bacteria. We present evidence that collections of T3Es from Sinorhizobium fredii and Bradyrhizobium japonicum are, in stark contrast to those of phytopathogenic bacteria, in a co-evolutionary equilibrium with their hosts. This equilibrium is characterized by highly conserved T3E collections consisting of many "core" T3Es with little variation in nucleotide sequence. The T3Es of Mesorhizobium loti MAFF303099 suggest a completely different picture of the evolution of T3Es. MAFF303099 recently acquired its T3SS locus, and the work in this thesis provides an evolutionary snapshot of a mutualist that is innovating a T3E collection primarily through horizontal gene transfer. Collectively, this work represents the first comprehensive catalog of T3Es of rhizobia and, in the case of Sinorhizobium and Bradyrhizobium, the first evidence of purifying selection for T3Es. / Graduation date: 2012
404

Catalizadores de Rh-soportado y su aplicación en la hidrogenación de crotonaldehído

Krstic, Vesna 19 July 2005 (has links)
Este trabajo ha sido realizado en el contexto de los proyectos de MAT 2002-03808 y MAT 2002-02158, financiados por la Dirección General de Investigación del Ministerio de Ciencia y Tecnología (MCyT). Se han sintetizado y caracterizado catalizadores Rh-soportado (sólo o promovido con Sn) utilizando diferentes tipos de soportes. Como soportes de catalizadores se utilizaron tanto materiales microporosos, silicatos laminares (bentonitas) de distinta procedencia y bentonitas modificadas mediante la introducción de pilares (PILC's) o transformadas en productos zeolíticos; como materiales mesoporosos, MCM-41, con una o dos fuentes de Silicio. Los mencionados catalizadores han sido aplicados en la hidrogenación de crotonaldehído, en fase gaseosa y condiciones suaves, de alto interés tanto académico como industrial en química fina, farmacéutica y alimentaria. Se han analizado y discutido la actividad/selectividad en relación con las diferentes características de los soportes y las distintas condiciones de trabajo como: temperatura de reducción del Rh, temperaturas de reacción, y presencia de estaño como promotor. Se han caracterizado los soportes y catalizadores mediante diferentes técnicas instrumentales UV-Vis, espectroscopia IR, ATG/DTG, DRX, isotermas de adsorción-desorción de N2, quimisorción de O2/H2, quimisorción de NH3, adsorción-desorción de piridina mediante espectroscopia IR-TF, XPS y se utilizó la Cromatografia de gases para la hidrogenación de crotonaldehído. Los resultados obtenidos ponen de manifiesto que tanto las arcillas de partida como las modificadas (con pilares o bien transformada en zeolitas) y materiales MCM-41, han resultado soportes idóneos para la formación de catalizadores heterogéneos de Rh y de Rh promovido con Sn, habiéndose generado, por tanto, nuevos materiales de alto valor añadido para el caso de las arcillas modificadas y nuevos retos de aplicación para los nuevos nanomateriales MCM-41. Así mismo se constata que la adición de Sn como promotor, modifica la conversión a todas las temperaturas de reacción, obteniéndose para todos los catalizadores, mayor selectividad hacia alcohol crotílico que en ausencia de Sn. En resumen, a lo largo de este trabajo se han logrado preparar catalizadores metal soportados utilizando unos nuevos soportes de catalizadores que muestran, generalmente, alta selectividad hacia alcohol crotílico en la hidrogenación de crotonaldehído, en condiciones suaves y a presión atmosférica, condiciones usuales de trabajo en la industria de química fina, farmacéutica y alimentaria, donde time mayor repercusión la aplicación de la reacción estudiada. / This work has been performed within the projects MAT 2002-03808 and MAT 2002-02158, financed by the DGESIC (Dirección General de Enseñanza Superior e Investigación y Ciencia) and CICYT (Comisión de Investigación Científica y Técnica), respectively.An Rh-supported catalyst (alone or promoted with Sn) has been synthesized and characterized using different types of supports. Aluminum silicate (clay) of different origins and clay modified by introduction of pillars (PILC's) or transformed into zeolytic products were used as microporous materials. MCM-41 (with one or two Silicon sources) was used as mesoporous materials. The catalyst has been applied in the hydrogenation of cortonaldehyde in gaseous phase and mild conditions. These have high academic and industrial interest. Activity and selectivity of catalysts have been analyzed at different conditions of work like: temperature of reduction of the Rh, temperatures of reaction and tin presence as promoter.These supports (micro and mesoporous materials) and catalysts have been characterized using different technical instruments: UV-Vis, spectroscopy IR, ATG/DTG, XRD, isotherms of adsorption-desorption of N2, chemisorptions of O2/H2, chemisorptions of NH3, adsorption-desorption of pyridine by DRIFTS, XPS and hydrogenation of crotonaldehyde by Gas Chromatography. The results obtained show that the natural clay material, as modified (with incorporation of pillars or transformed into zeolites), and materials MCM-41, have been good supports to the formation of heterogeneous catalysts of Rh and Rh promoted with Sn, having generated new materials of high value in the case of modified clays and raises new challenges of application for nanomaterials MCM-41. Also observed is that the addition of Sn as promoter was modifying the conversion at all temperatures of reaction, obtaining for all the catalysts greater selectivity to crotyl alcohol than without tin (Sn).In summary, throughout this work, we have been able to prepare and obtain metal supported catalysts using new supports of catalysts that show great selectivity towards crotyl alcohol in the hydrogenation of crotonaldehyde in mild conditions and atmospheric pressure. This is a very important reaction in the production of many pharmaceutical, agrochemical and fragrance compounds, having great repurcussion on the application of the studied reaction and attracting much interest in fundamental research in catalysis.
405

"Outside I´m smiling, but inside I´m crying." : En kunskapsöversikt av faktorer som påverkar de asylsökande barnen

Larsson, Ulrika, Eriksson, Margaretha January 2012 (has links)
Studiens syfte var att klargöra och redovisa för de främjande och försämrande faktorer som är betydelsefulla för asylsökande barns psykosociala välmående. Enligt vår förförståelse som vi erhållit genom arbetslivserfarenhet och utbildning lever de asylsökande barnen under svåra omständigheter och vi ansåg det viktigt att undersöka de påverkande faktorerna. Den metod som användes var en kunskapsöversikt som tolkades hermeneutiskt. Kunskapsöversikten baserades på 10 primärstudier och resultaten visade på följande främjande faktorer; skola, föräldrar/familj, adekvat information gällande beslutsprocessen, en väl fungerande barnpsykiatrisk vård, sociala nätverk och fritidsaktiviteter. De försämrande faktorerna var; bristfällig information och lång väntan under asylprocessen, föräldrars ohälsa, okunskap hos professionella om barnens lagstadgade rättigheter samt osäkra boendevillkor. Studiens resultat analyserades utifrån teorin Känsla av sammanhang. Resultatet ligger i linje med tidigare forskning. / "Outside I´m smiling, but inside I´m crying" - A litterary review of factors affecting the asylum seeking children´s psychosocial health. The study´s purpose was to examine the promoting and detoriating factors that are of importance for the psychosocial well-being of children seeking asylum. According to our prior understanding which we have acquired through working experience and education the asylum seeking children lives under difficult circumstances. We therefor considered it important to investigate the factors that are influencing the children. The method used was a review of the litterature which was interpreted hermeneutically. The review was based on 10 primary studies and results showed promoting factors as; school, parents/family, adequate information regarding the decision-making, a well-functioning child mental health service, social networks and leisure activities. The deteriorative factors were; lack of information and delays during the asylum process, parents´illness, ignorance among professionals about children´s legal rights and unsafe housing conditions. Our results were analysed based on the theory Sense of coherence. The results are in line with previous research.
406

Multiple prediction from incomplete data with the focused curvelet transform

Herrmann, Felix J., Wang, Deli, Hennenfent, Gilles January 2007 (has links)
Incomplete data represents a major challenge for a successful prediction and subsequent removal of multiples. In this paper, a new method will be represented that tackles this challenge in a two-step approach. During the first step, the recenly developed curvelet-based recovery by sparsity-promoting inversion (CRSI) is applied to the data, followed by a prediction of the primaries. During the second high-resolution step, the estimated primaries are used to improve the frequency content of the recovered data by combining the focal transform, defined in terms of the estimated primaries, with the curvelet transform. This focused curvelet transform leads to an improved recovery, which can subsequently be used as input for a second stage of multiple prediction and primary-multiple separation.
407

Evaluating the efficacy of exogenous composite microbial enzymes in maize-soybean based broiler chicken feeds.

Ngxumeshe, Ayanda Mavis. January 2006 (has links)
This research reported here was carried out to examine alternatives to antibiotic growth promoters as a result of their being banned in the animal feed industry. Four experiments were conducted to evaluate the efficacy of non-medicated feed additives as replacements for antibiotic growth promoters in broiler feeds. The additives used were enzymes (a new thermo-tolerant powder enzyme called TXAP, phytase, lipase and a new phytase enzyme derived from E. coli called phyzyme XP), organic acid (Acid Pak), prebiotic (Bio-Mos®) and probiotic (All-Lac XCL). Mashed maize-soya based feeds were used in all the experiments, which were conducted in litter-floor pens. The first experiment was a dose-response trial. Broilers in eight replicate pens of 50 males and 50 females were fed unsupplemented feeds and five additional feeds containing increasing levels of TXAP, from 0.5 to 2.5 g/kg to 42 d. The second experiment used enzyme TXAP with two different enzymes (phytase and lipase), individually or in combination. Six replicate pens of 50 males and 50 females were fed either unsupplemented feeds or one of six additional feeds treated with TXAP, lipase, phytase , a combination of TXAP and lipase, a combination of TXAP and phytase or a combination of all the three enzymes . This trial continued for 42 d. In the third experiment three types of TXAP (Lot 1, 2 and 3) were used, with fixed levels of xylanase and amylase but varying levels of protease activities (4000, 2000 and 1000 U/kg for Lot 1, 2 and 3, respectively) in combination with phyzyme XP for 35 d. The fourth experiment used mannan-oligosaccharide (Bio-Mos®), organic acid (Acid pak 2x), probiotic (All Lac XCL 5x), individually or in combination and an antibiotic growth promoter (Zinc bacitracin) for 42 d. The chickens in this experiment were challenged with Clostridium perfringens (CP) at 21, 22 and 23 d to determine the efficacy of these additives for replacing antibiotics in hindering the effects of CP on the villus surface area. The dose-response trial did not show any significant improvement in broiler performance with any level of inclusion of enzyme TXAP. The results from this study showed some beneficial effects with the use of enzyme TXAP when fed alone and at a young age. Its use when combined with other enzymes and at later stages of growth needs further investigation. Feed additives in experiment 4 prevented the negative effects of CP as the treated chickens did not have lesions on their villus surfaces. The conditions under which these trials were conducted appeared to be such that little benefit was derived from the use of any of the feed additives used. It is possible that under less-hygienic conditions such as those in commercial operations greater benefits from these additives may be realised. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
408

Identification de modifications post-traductionnelles de Staufen1 et étude de leur fonction régulatrice

Boulay, Karine 08 1900 (has links)
La régulation post-transcriptionnelle joue un rôle de premier plan dans le contrôle fin de l’expression génique en permettant une modulation de la synthèse de protéines dans le temps et l’espace, en fonction des besoins de la cellule. Ainsi, des protéines reconnaissant des éléments d’ARN présents sur des transcrits peuvent influencer toutes les étapes de leur existence, soit leur épissage, leur export nucléaire, leur localisation subcellulaire, leur traduction et leur dégradation. Staufen1 (Stau1) est un membre de la famille des protéines liant l’ARN double-brin qui contribue à la régulation post-transcriptionnelle par son implication dans des mécanismes qui vont promouvoir l’épissage alternatif, le transport, la dé-répression de la traduction et l’induction de la dégradation d’ARN messagers (ARNm) spécifiques. L’identité des cibles potentielles de Stau1 est maintenant connue puisqu’une étude à l’échelle du génome a montré que la protéine s’associe à près de 7% du transcriptome des cellules HEK293T. Ces ARNm se classent dans un large éventail de catégories fonctionnelles, mais il est tout de même intéressant de noter qu’une grande proportion d’entre eux code pour des protéines reliées au métabolisme cellulaire et à la régulation de processus cellulaires. En considérant toutes ces informations, nous avons émis l’hypothèse que les différentes activités de Stau1 puissent être modulées afin de contrôler adéquatement l’expression des transcrits liés par la protéine. Dans la mesure où certains ARNm faisant partie des complexes définis par la présence de Stau1 codent pour des régulateurs clés de la prolifération cellulaire, nous avons voulu examiner si l’expression de la protéine varie au cours du cycle de division cellulaire. Nous avons montré que l’abondance de Stau1 est maximale en début de mitose et qu’elle diminue ensuite lorsque les cellules complètent la division cellulaire. Nous avons ensuite découvert que cette baisse d’expression de Stau1 en sortie de mitose dépend du complexe promoteur d’anaphase/cyclosome (APC/C). En soutien à l’idée que Stau1 soit une cible de cette ubiquitine ligase de type E3, nous avons de plus démontré que Stau1 est ubiquitiné et dégradé par le protéasome. Ce contrôle des niveaux de Stau1 semble important puisque la surexpression de la protéine retarde la sortie de mitose et entraîne une diminution importante de la prolifération cellulaire. Par ailleurs, nous avons supposé que les différentes fonctions de Stau1 puissent également être sujettes à une régulation. Compte tenu que les activités de nombreuses protéines liant l’ARN peuvent être contrôlées par des modifications post-traductionnelles telles que la phosphorylation, nous avons voulu tester la possibilité que Stau1 soit phosphorylé. L’immunopurification de Stau1 et son analyse par spectrométrie de masse nous a permis d’identifier trois phosphosites dans la protéine. L’évaluation du rôle de ces événements de phosphorylation à l’aide de mutants phoshomimétiques ou non-phoshorylables a révélé que la modification de Stau1 pourrait compromettre son association à la protéine UPF1. Comme cette interaction est nécessaire pour déstabiliser les transcrits liés par Stau1, nos résultats suggèrent fortement que la fonction de Stau1 dans la dégradation d’ARNm est régulée négativement par sa phosphorylation. Toutes ces données mettent en lumière l’importance des modifications post-traductionnelles telles que l’ubiquitination et la phosphorylation dans la modulation de l’expression et des fonctions de Stau 1. Somme toute, il est vraisemblable que ces mécanismes de contrôle puissent avoir un impact significatif sur le destin des ARNm liés par Stau1, particulièrement dans un contexte de progression dans le cycle cellulaire. / Post-transcriptional regulation plays a major role in the fine tuning of gene expression by allowing a modulation of protein synthesis in space and time, according to cellular requirements. For instance, proteins recognizing RNA elements on transcripts can influence all the steps of their existence, such as their splicing, nuclear export, subcellular localization, translation and degradation. Staufen1 (Stau1) is a member of the double-stranded RNA-binding protein family that contributes to the post-transcriptional regulation of gene expression by its involvement in mechanisms that promote alternative splicing, transport, de-repression of translation and decay of specific messenger RNAs (mRNAs). The identity of potential Stau1 targets is now known as genome-wide analyses have shown that the protein is associated with about 7% of the HEK293T cell transcriptome. Although these mRNAs are classified in a broad range of functional categories, a large proportion of them code for proteins related to cellular metabolism and regulation of cellular processes. Considering all this information, we hypothesized that the different activities of Stau1 may be modulated in order to control appropriately the expression of Stau1-bound mRNAs. Since some of the mRNAs that are part of Stau1-containing complexes encode key regulators of cell proliferation, we wanted to examine whether Stau1 expression fluctuates during the cell division cycle. We showed that Stau1 abundance peaks at the onset of mitosis and then decreases as cells complete division. We then found that Stau1 down-regulation in mitosis exit is mediated by the anaphase promoting complex/cyclosome (APC/C). To support the idea that Stau1 is a target of this E3-ubiquitin ligase, we further demonstrated that Stau1 is ubiquitinated and degraded by the proteasome. The importance of controlling Stau1 levels during the cell cycle is underscored by the observation that its overexpression delays mitotic exit and impairs cell proliferation. Furthermore, we speculated that Stau1 different functions may also be regulated. In the view that the activities of numerous RNA-binding proteins can be controlled by post-translational modifications such as phosphorylation, we tested the possibility that Stau1 is phosphorylated. Mass spectrometry analysis of immunopurified Stau1 allowed the identification of three phosphosites in this protein. Assessment of the role of these phosphorylation events using phosphomimetic or non-phosphorylatable mutants revealed that Stau1 phosphorylation may compromise its association with Upf1. Because this interaction is necessary to elicit the destabilisation of Stau1-bound RNAs, our results strongly suggest that Stau1 function in mRNA decay is negatively regulated by its phosphorylation. Collectively, these data highlight the importance of post-translational modifications such as ubiquitination and phosphorylation in the modulation of Stau1 expression and functions. Overall, the mechanisms that control Stau1 are likely to have a significant impact on the fate of Stau1-bound mRNAs, especially in the context of cell cycle progression.
409

Lösningsfokuserat arbetssätt : En kvalitativ studie om hur chefer i offentlig sektor använder lösningsfokuserat arbetssätt

Holmgren, Hanna January 2018 (has links)
Studien ämnade att undersöka området för lösningsfokuserat arbetssätt. Lösningsfokuserat arbetssätt handlar om att skifta fokus från problem till att istället fokusera på lösningar. Tidigare har arbetssättet främst initierats i klientsamtal men idag är det även förekommande inom ledarskap. Lösningsfokuserat ledarskap handlar om att hjälpa medarbetaren hitta vägar framåt med fokus på målet som medarbetaren har. Studiens syfte var att undersöka hur chefer inom den offentliga sektorn använder lösningsfokuserat arbetssätt och hur cheferna upplever att det fungerar i organisationen och i relationen med medarbetarna. En kvalitativ forskningsansats valdes som metod med semistrukturerade intervjuer som datainsamlingsmetod. Vid analys av det insamlade materialet genomfördes en manifest innehållsanalys. Studiens resultat visar att chefernas intresse för lösningsfokuserat arbetssätt väcktes för att det fokuserade på lösningar istället för problem. Detta kan koppla samman med ett salutogent perspektiv, där det handlar om att fokusera på vad som gör människor friska istället för på vad som gör människor sjuka. Cheferna upplevde också att de arbetar med lösningsfokus som en pågående process och hade bland annat uppnått resultat i form av delaktighet, kreativitet och medskapande hos medarbetarna. Detta kan kopplas till socialkonstruktion, vilket är utgångspunkten för lösningsfokuserat arbetssätt. Då handlar det om att verkligheten skapas i dialogen mellan människor. Cheferna upplevde också att effektiviteten hade ökat inom organisationen och att det hade resulterat i ett öppnare klimat på arbetsplatsen. Detta i sin tur kan kopplas samman med hälsofrämjande arbetsplatser då det är viktigt att det finns utvecklingsmöjligheter och möjlighet till välmående. / The intention with this study was to gain broader understanding for solution-focused brief therapy. Solution-focused brief therapy is a method that is shifting focus from problems to focus on solutions instead. Previously, the work method has been initiated in client talks, but today it is also used in leadership. Solution-focused leadership is about helping employees to find ways forward with a focus on the goal that they have. It is about asking solution-focused questions. The aim of the study was to investigate how public sector managers use solution-focused brief therapy methods and how they experience that the method works in the organization and in the relationship with the co-workers. A qualitative research method was chosen with semi-structured interviews as the data collection method. When analyzing the collected material a manifest content analysis was conducted. The results of the study show that the managers’ interest for solution-focused approaches was created because it focused on solutions instead of problems. This can be linked to a salutogenic perspective, which focuses on what makes people healthy instead of what makes people sick. The managers also experience that working with solution-focus is an ongoing process and, among other things, achieved results in terms of participation, creativity and employee co-creation. This can be linked to social construction where solution-focused work methods have it origins from. In social construction it is about creating reality in the dialogue between people. The managers also felt that the efficiency had increased within the organization and that it had resulted in a more open climate at the workplace. This in turn can be linked to health-promoting workplaces as it is important that there are development opportunities and opportunities for well-being.
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The Swedish Connection : Exploring the Social Network of Violent and Violence-Promoting Islamist Extremism in Sweden and its Connections to the Global Jihad

Gustafsson, Linus January 2012 (has links)
This study examines who is part of the Swedish network of violent and violence-promoting Islamist extremism and whether the social network is a case of „new social movement‟. Through a social network analysis of violent and violence-promoting Islamist extremists in Sweden the results shows that there is a loose Swedish network with global nodes. The social network in Sweden is analyzed through the framework of New Social Movement theory and the connections between the global jihad and the Swedish network are examined. The result is that the network cannot be seen as a case of „new social movement‟. However, several individuals of the network can be seen as part of the global jihad and therefore a case of „new social movement‟. More academic research is needed on violent and violence-promoting Islamist extremism in Sweden, especially on why and how these actors are radicalized. In addition, more research is needed on how to prevent and counter violent and violence-promoting Islamist extremism.

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