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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.
41

Stabila föräldrar för barnets bästa : Hur statliga riktlinjer för IVF-utredningar konstruerar goda föräldrar och påverkar tillgången till föräldraskap för personer med psykiska funktionsnedsättningar

Bergman, Emma January 2023 (has links)
This thesis investigates the access to IVF-treatment for people with psychiatric disabilities who intend to carry the child themselves. It explores how the Swedish welfare state resonates around people with psychiatric disabilities wanting to become parents, and how their reproductive rights might differ from others seeking the same treatment. Therefore, different official reports from the Swedish government and documents from the National Board of Health and Welfare that deals with the legal framework and state-sanctioned guidelines for medical professionals regarding IVF has been examined in a qualitive discourse analysis. Two interviews with two medical professionals working with IVF has also been conducted. The focus has been on the psychosocial interviews every treatment-seeking individual has to go through to determine if they are fit as parents. The main body of theory consists of work surrounding feminist disability studies, crip theory, discourse analysis, repronormativity and critical studies of the welfare state. This thesis set out to investigate how the demand from the government to put the best interest of the child first when deciding over who gets access to IVF are used to resonate around if people with psychiatric disabilities can be seen as fit parents. It also seeks to understand what these state-sanctioned guidelines and the way medical professionals interacts with them can say about the reproductive politics of the Swedish welfare state regarding people with psychiatric disabilities. The general conclusion is that the welfare state has implemented tools for reproductive control over the group that has been studied (particularly women and trans people) since at least the 1930’s, and while there has been significant change, the gatekeeping practises surrounding IVF can be seen as another tool for reproductive control. It is evident that people with psychiatric disabilities have to prove themselves in order to be seen as fit parents, and it is assumed that there is a risk trying to combine their psychiatric disabilities with the best interest of the child. While there is no legal framework denying this group access to IVF outright, this thesis shows that they face challenges to gain that access that people without psychiatric disabilities does not.
42

"HILFE ZUR ARBEIT" nach dem Bundessozialhilfegesetz - eine wirkliche Chance oder wirklich nur eine Chance ? / Eine Datenanalyse der drei sächsischen Großstädte Dresden, Leipzig und Chemnitz im Hinblick auf die praktische Umsetzung und ihre Wirksamkeit und daraus ableitbare Schlussfolgerungen

Ebersbach, Romy 22 May 2004 (has links) (PDF)
Die Dissertation beschäftigt sich mit dem Thema "Hilfe zur Arbeit" nach dem BSHG. Grundsätzlich zielen alle mit Hilfe zur Arbeit im Zusammenhang stehenden Paragraphen des BSHG auf (Re-)Integration der Hilfeempfänger in den ersten Arbeitsmarkt und die Aktivierung der Selbsthilfekräfte. Unter Berücksichtigung der Zumutbarkeitskriterien geht die Bundesregierung von knapp einer Million benötigter Arbeitsplätzen aus, um alle in Frage kommenden Empfänger von laufender Hilfe zum Lebensunterhalt in den Arbeitsmarkt zu integrieren. Die Schaffung und Akquise dieser Arbeitsplätze sind Aufgaben der Kommunen. Die vorliegende Studie spiegelt wieder, wie die Städte Dresden, Leipzig und Chemnitz die Paragraphen 18 bis 20 und 25 des BSHG bis zum Jahr 2000 in ihre Praxis umsetzten und welche Schlüsse sich daraus für das Gelingen einer beschäftigungsorientierten kommunalen Sozialpolitik unter lokalen Bedingungen ableiten lassen. Im von mir untersuchten Zeitraum führten alle drei Städte Maßnahmen der "Hilfe zur Arbeit" durch. Jede der Kommunen entwickelte eigene Konzepte zur Umsetzung der gesetzlichen Vorgaben. Zusammenfassend stelle ich fest, dass die Chancen auf einen Arbeitsplatz im Bereich des ersten Arbeitsmarktes, neben der direkten Einstellung mit Hilfe von Lohnkostenzuschüssen, im Anschluss an Maßnahmen mit Arbeitsvertrag am größten sind. Voraussetzung ist allerdings, dass der Hilfeempfänger ein Jahr sozialversicherungspflichtig beschäftigt war. Ich komme also mit Hilfe meiner Studie zu dem Ergebnis, dass "Hilfe zur Arbeit" nach dem BSHG für die Sozialhilfeempfänger lediglich eine äußerst geringe Chance darstellt, einen Arbeitsplatz auf dem ersten Arbeitsmarkt zu bekommen. Keinesfalls handelt es sich hierbei um eine wirkliche Chance und gleich recht nicht um ein Instrument, welches in der Lage ist Massenarbeitslosigkeit zu bekämpfen. Die Mehrzahl der Hilfeempfänger findet auf diesem Weg keine Arbeit auf dem ersten Arbeitsmarkt.
43

Exorcising Intersex and Cripping Compulsory Dyadism

Orr, Celeste E. 08 May 2018 (has links)
Using hauntology as a linchpin, this dissertation explores the undertheorized connection between intersex and disability. Building on important feminist research in the fields of intersex, queer, disability, crip, and hauntology studies, I ask, how do we understand and reconcile the contested meanings, responses to, and effects of intersex? Intersex is “a perpetually shifting phantasm” (Holmes 2002: 175), yet intersex is typically represented and treated as innate disorder, disability, or disease by medical professionals. That said, many intersex people appear to distance from disability. By engaging intersex studies with feminist disability and crip theories, however, I demonstrate that an intersex politic and intersex studies must be rooted in a disability politic and disability studies. Through a feminist disability and crip lens, I conduct a textual and critical discourse analysis of three case studies of interphobic violence or, what I term, “compulsory dyadism,” meaning the instituted cultural mandate that people cannot have intersex traits or house the “spectre of intersex” (Sparrow 2013: 29); such a spectre must be exorcised. The three case studies include nonconsensual medical interventions, sport sex testing, and employing reproductive technologies to select against intersex variations. My analyses of these case studies produce three important observations. First, intersex is presently and effectively being integrated into conventional notions of disability; second, ableist logics underpin interphobic violence; and third, compulsory dyadism is intertwined with, or is an iteration of, compulsory able-bodiedness. In recognizing this interconnection, theorizing intersex and disability together is not merely beneficial, doing so is necessary. Ultimately, my dissertation interrogates and extends questions of the ever-shifting categorization of body-minds, culturally mandated ways of being, and (the haunting effects of) pathologization. I apply pressure to the academic field of intersex studies as well as intersex activist and advocate communities to center disability in discussions concerning intersex human rights and interphobia.
44

Kompaktní město - aneb co nového se může ještě dít v Brně mezi nádražími / Compact City - or what new is able to yet be done in Brno among railway stations

Hill, Petr January 2010 (has links)
Diploma project seeks for new visions in urban solutions of area south of Brno main railway station. This place could become an interesting space for new spacial creativity in connection with the project of new railway station. The work looks for alternatives to officially presented projects with orderly and straight street layouts to create pleasing and livable public space, which would become not only the tour from station to the city, but the city itself. Six meters of height difference is used to separate road and pedestrian traffic and offers an undisturbed walking movement through the elevated pedestrian streets, which are not so deep as they would be when on the ground level, so their width could be downsized to a pleasant minumum, whereas all necesary functions (like parking and supplies areas) také place below it. Geometrical concept of two shifted hexagonal grids delivers a practical large blocks on the ground level for parking and divides the area into separate projects. The walking streets` grid fractionates big portions into more subtle building block layout so comfortable for pedestrian movement. Project also deals with development phases of area to protect it from nonreversible tenous development at the beginning. The structure works as a lively city in the very beginning of the development.
45

"HILFE ZUR ARBEIT" nach dem Bundessozialhilfegesetz - eine wirkliche Chance oder wirklich nur eine Chance ?: Eine Datenanalyse der drei sächsischen Großstädte Dresden, Leipzig und Chemnitz im Hinblick auf die praktische Umsetzung und ihre Wirksamkeit und daraus ableitbare Schlussfolgerungen

Ebersbach, Romy 28 May 2004 (has links)
Die Dissertation beschäftigt sich mit dem Thema "Hilfe zur Arbeit" nach dem BSHG. Grundsätzlich zielen alle mit Hilfe zur Arbeit im Zusammenhang stehenden Paragraphen des BSHG auf (Re-)Integration der Hilfeempfänger in den ersten Arbeitsmarkt und die Aktivierung der Selbsthilfekräfte. Unter Berücksichtigung der Zumutbarkeitskriterien geht die Bundesregierung von knapp einer Million benötigter Arbeitsplätzen aus, um alle in Frage kommenden Empfänger von laufender Hilfe zum Lebensunterhalt in den Arbeitsmarkt zu integrieren. Die Schaffung und Akquise dieser Arbeitsplätze sind Aufgaben der Kommunen. Die vorliegende Studie spiegelt wieder, wie die Städte Dresden, Leipzig und Chemnitz die Paragraphen 18 bis 20 und 25 des BSHG bis zum Jahr 2000 in ihre Praxis umsetzten und welche Schlüsse sich daraus für das Gelingen einer beschäftigungsorientierten kommunalen Sozialpolitik unter lokalen Bedingungen ableiten lassen. Im von mir untersuchten Zeitraum führten alle drei Städte Maßnahmen der "Hilfe zur Arbeit" durch. Jede der Kommunen entwickelte eigene Konzepte zur Umsetzung der gesetzlichen Vorgaben. Zusammenfassend stelle ich fest, dass die Chancen auf einen Arbeitsplatz im Bereich des ersten Arbeitsmarktes, neben der direkten Einstellung mit Hilfe von Lohnkostenzuschüssen, im Anschluss an Maßnahmen mit Arbeitsvertrag am größten sind. Voraussetzung ist allerdings, dass der Hilfeempfänger ein Jahr sozialversicherungspflichtig beschäftigt war. Ich komme also mit Hilfe meiner Studie zu dem Ergebnis, dass "Hilfe zur Arbeit" nach dem BSHG für die Sozialhilfeempfänger lediglich eine äußerst geringe Chance darstellt, einen Arbeitsplatz auf dem ersten Arbeitsmarkt zu bekommen. Keinesfalls handelt es sich hierbei um eine wirkliche Chance und gleich recht nicht um ein Instrument, welches in der Lage ist Massenarbeitslosigkeit zu bekämpfen. Die Mehrzahl der Hilfeempfänger findet auf diesem Weg keine Arbeit auf dem ersten Arbeitsmarkt.
46

Human Pose and Action Recognition using Negative Space Analysis

Janse Van Vuuren, Michaella 12 1900 (has links)
This thesis proposes a novel approach to extracting pose information from image sequences. Current state of the art techniques focus exclusively on the image space occupied by the body for pose and action recognition. The method proposed here, however, focuses on the negative spaces: the areas surrounding the individual. This has resulted in the colour-coded negative space approach, an image preprocessing step that circumvents the need for complicated model fitting or template matching methods. The approach can be described as follows: negative spaces surrounding the human silhouette are extracted using horizontal and vertical scanning processes. These negative space areas are more numerous, and undergo more radical changes in shape than the single area occupied by the figure of the person performing an action. The colour-coded negative space representation is formed using the four binary images produced by the scanning processes. Features are then extracted from the colour-coded images. These are based on the percentage of area occupied by distinct coloured regions as well as the bounding box proportions. Pose clusters are identified using feedback from an independent action set. Subsequent images are classified using a simple Euclidean distance measure. An image sequence is thus temporally segmented into its corresponding pose representations. Action recognition simply becomes the detection of a temporally ordered sequence of poses that characterises the action. The method is purely vision-based, utilising monocular images with no need for body markers or special clothing. Two datasets were constructed using several actors performing different poses and actions. Some of these actions included actors waving their arms, sitting down or kicking a leg. These actions were recorded against a monochrome background to simplify the segmentation of the actors from the background. The actions were then recorded on DV cam and digitised into a data base. The silhouette images from these actions were isolated and placed in a frame or bounding box. The next step was to highlight the negative spaces using a directional scanning method. This scanning method colour-codes the negative spaces of each action. What became immediately apparent is that very distinctive colour patterns formed for different actions. To emphasise the action, different colours were allocated to negative spaces surrounding the image. For example, the space between the legs of an actor standing in a T - pose with legs apart would be allocated yellow, while the space below the arms were allocated different shades of green. The space surrounding the head would be different shades of purple. During an action when the actor moves one leg up in a kicking fashion, the yellow colour would increase. Inversely, when the actor closes his legs and puts them together, the yellow colour filling the negative space would decrease substantially. What also became apparent is that these coloured negative spaces are interdependent and that they influence each other during the course of an action. For example, when an actor lifts one of his legs, increasing the yellow-coded negative space, the green space between that leg and the arm decreases. This interrelationship between colours hold true for all poses and actions as presented in this thesis. In terms of pose recognition, it is significant that these colour coded negative spaces and the way the change during an action or a movement are substantial and instantly recognisable. Compare for example, looking at someone lifting an arm as opposed to seeing a vast negative space changing shape. In a controlled research environment, several actors were instructed to perform a number of different actions. After colour coding the negative spaces, it became apparent that every action can be recognised by a unique colour coded pattern. The challenge is to ascribe a numerical presentation, a mathematical quotation, to extract the essence of what is so visually apparent. The essence of pose recognition and it's measurability lies in the relationship between the colours in these negative spaces and how they impact on each other during a pose or an action. The simplest way of measuring this relationship is by calculating the percentage of each colour present during an action. These calculated percentages become the basis of pose and action recognition. By plotting these percentages on a graph confirms that the essence of these different actions and poses can in fact been captured and recognised. Despite variations in these traces caused by time differences, personal appearance and mannerisms, what emerged is a clear recognisable pattern that can be married to an action or different parts of an action. 7 Actors might lift their left leg, some slightly higher than others, some slower than others and these variations in terms of colour percentages would be recorded as a trace, but there would be very specific stages during the action where the traces would correspond, making the action recognisable.In conclusion, using negative space as a tool in human pose and tracking recognition presents an exiting research avenue because it is influenced less by variations such as difference in personal appearance and changes in the angle of observation. This approach is also simplistic and does not rely on complicated models and templates
47

Zabezpečovací systém pro rodinný dům / Security system for family house

Sohr, Martin January 2012 (has links)
Family house, security system, wireless communication, IQRF, RSA, central control unit, SPI, I2C, glass break sensors, motion sensors, magnetic contact sensors, graphic displey, LCD displey, microcontroler, SIM900, 24FJ256GB106, EA DOGM106, eDIPTFT43-A.
48

An Introductory Course in the Reading of Simple Graphic and Statistical Material for Use in Junior High Schools

McKenzie, Annie 01 January 1930 (has links) (PDF)
In the stories of olden times and in those of our own American Indians, we learned of the picture writing of primitive peoples. It became an early method of recording people's thoughts. This was a very useful method at a time when the race was young. This in turn was the beginning of our alphabet, later the beginning of shaping letters into words, and then word into sentences and paragraphs. As our world has grown older, new idea have come into use and we are no longer content to live as our grandparents lived. We travel by fast express trains, high powered auto- mobiles, airplanes, or zeppelins. The radio gives us the news before our papers containing it are on the street. are not able to talk with people on the other side of the world. Business men find this a very valuable means of doing business when time means money. The motion pictures bring us the story of the book we have not had time to read and the characters from its pages talk to us from the screen. In short, we must have quicker ways of doing things.
49

O envolvimento da proteína adaptadora 1 (AP-1) no mecanismo de regulação negativa do receptor CD4 por Nef de HIV-1 / The involvement of Adaptor Protein 1 (AP-1) on the Mechanism of CD4 Down-regulation by Nef from HIV-1

Tavares, Lucas Alves 05 August 2016 (has links)
O Vírus da Imunodeficiência Humana (HIV) é o agente etiológico da Síndrome da Imunodeficiência Adquirida (AIDS). A AIDS é uma doença de distribuição mundial, e estima-se que existam atualmente pelo menos 36,9 milhões de pessoas infectadas com o vírus. Durante o seu ciclo replicativo, o HIV promove diversas alterações na fisiologia da célula hospedeira a fim de promover sua sobrevivência e potencializar a replicação. A rápida progressão da infecção pelo HIV-1 em humanos e em modelos animais está intimamente ligada à função da proteína acessória Nef. Dentre as diversas ações de Nef está a regulação negativa de proteínas importantes na resposta imunológica, como o receptor CD4. Sabe-se que esta ação resulta da indução da degradação de CD4 em lisossomos, mas os mecanismos moleculares envolvidos ainda são totalmente elucidados. Nef forma um complexo tripartite com a cauda citosólica de CD4 e a proteína adaptadora 2 (AP-2), em vesículas revestidas por clatrina nascentes, induzindo a internalização e degradação lisossomal de CD4. Pesquisas anteriores demonstraram que o direcionamento de CD4 aos lisossomos por Nef envolve a entrada do receptor na via dos corpos multivesiculares (MVBs), por um mecanismo atípico, pois, embora não necessite da ubiquitinação de carga, depende da ação de proteínas que compõem os ESCRTs (Endosomal Sorting Complexes Required for Transport) e da ação de Alix, uma proteína acessória da maquinaria ESCRT. Já foi reportado que Nef interage com subunidades dos complexos AP-1, AP-2, AP-3 e Nef não parece interagir com subunidades de AP-4 e AP-5. Entretanto, o papel da interação de Nef com AP-1 e AP-3 na regulação negativa de CD4 ainda não está totalmente elucidado. Ademais, AP-1, AP-2 e AP-3 são potencialmente heterogêneos devido à existência de isoformas múltiplas das subunidades codificadas por diferentes genes. Todavia, existem poucos estudos para demonstrar se as diferentes combinações de isoformas dos APs são formadas e se possuem propriedades funcionais distintas. O presente trabalho procurou identificar e caracterizar fatores celulares envolvidos na regulação do tráfego intracelular de proteínas no processo de regulação negativa de CD4 induzido por Nef. Mais especificamente, este estudo buscou caracterizar a participação do complexo AP-1 na modulação negativa de CD4 por Nef de HIV-1, através do estudo funcional das duas isoformas de ?-adaptina, subunidades de AP-1. Utilizando a técnica de Pull-down demonstramos que Nef é capaz de interagir com ?2. Além disso, nossos dados de Imunoblot indicaram que a proteína ?2-adaptina, e não ?1-adaptina, é necessária no processo de degradação lisossomal de CD4 por Nef e que esta participação é conservada para degradação de CD4 por Nef de diferentes cepas virais. Ademais, por citometria de fluxo, o silenciamento de ?2, e não de ?1, compromete a diminuição dos níveis de CD4 por Nef da membrana plasmática. A análise por imunofluorêsncia indireta também revelou que a diminuição dos níveis de ?2 impede a redistribuição de CD4 por Nef para regiões perinucleares, acarretando no acúmulo de CD4, retirados por Nef da membrana plasmática, em endossomos primários. A depleção de ?1A, outra subunidade de AP-1, acarretou na diminuição dos níveis celulares de ?2 e ?1, bem como, no comprometimento da eficiente degradação de CD4 por Nef. Além disso, foi possível observar que, ao perturbar a maquinaria ESCRT via super-expressão de HRS (uma subunidade do complexo ESCRT-0), ocorreu um acumulo de ?2 em endossomos dilatados contendo HRS-GFP, nos quais também detectou-se CD4 que foi internalizado por Nef. Em conjunto, os resultados indicam que ?2-adaptina é uma importante molécula para o direcionamento de CD4 por Nef para a via ESCRT/MVB, mostrando ser uma proteína relevante no sistema endo-lisossomal. Ademais, os resultados indicaram que as isoformas ?-adaptinas não só possuem funções distintas, mas também parecem compor complexos AP-1 com diferentes funções celulares, já que apenas a variante AP-1 contendo ?2, mas não ?1, participa da regulação negativa de CD4 por Nef. Estes estudos contribuem para o melhor entendimento dos mecanismos moleculares envolvidos na atividade de Nef, que poderão também ajudar na melhor compreensão da patogênese do HIV e da síndrome relacionada. Em adição, este trabalho contribui para o entendimento de processos fundamentais da regulação do tráfego de proteínas transmembrana no sistema endo-lisossomal. / The Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). AIDS is a disease which has a global distribution, and it is estimated that there are currently at least 36.9 million people infected with the virus. During the replication cycle, HIV promotes several changes in the physiology of the host cell to promote their survival and enhance replication. The fast progression of HIV-1 in humans and animal models is closely linked to the function of an accessory protein Nef. Among several actions of Nef, one is the most important is the down-regulation of proteins from the immune response, such as the CD4 receptor. It is known that this action causes CD4 degradation in lysosome, but the molecular mechanisms are still incompletely understood. Nef forms a tripartite complex with the cytosolic tail of the CD4 and adapter protein 2 (AP-2) in clathrin-coated vesicles, inducing CD4 internalization and lysosome degradation. Previous research has demonstrated that CD4 target to lysosomes by Nef involves targeting of this receptor to multivesicular bodies (MVBs) pathway by an atypical mechanism because, although not need charging ubiquitination, depends on the proteins from ESCRTs (Endosomal Sorting Complexes Required for Transport) machinery and the action of Alix, an accessory protein ESCRT machinery. It has been reported that Nef interacts with subunits of AP- 1, AP-2, AP-3 complexes and Nef does not appear to interact with AP-4 and AP-5 subunits. However, the role of Nef interaction with AP-1 or AP-3 in CD4 down-regulation is poorly understood. Furthermore, AP-1, AP-2 and AP-3 are potentially heterogeneous due to the existence of multiple subunits isoforms encoded by different genes. However, there are few studies to demonstrate if the different combinations of APs isoforms are form and if they have distinct functional properties. This study aim to identify and characterize cellular factors involved on CD4 down-modulation induced by Nef from HIV-1. More specifically, this study aimed to characterize the involvement of AP-1 complex in the down-regulation of CD4 by Nef HIV-1 through the functional study of the two isoforms of ?-adaptins, AP-1 subunits. By pull-down technique, we showed that Nef is able to interact with ?2. In addition, our data from immunoblots indicated that ?2- adaptin, not ?1-adaptin, is required in Nef-mediated targeting of CD4 to lysosomes and the ?2 participation in this process is conserved by Nef from different viral strains. Furthermore, by flow cytometry assay, ?2 depletion, but not ?1 depletion, compromises the reduction of surface CD4 levels induced by Nef. Immunofluorescence microscopy analysis also revealed that ?2 depletion impairs the redistribution of CD4 by Nef to juxtanuclear region, resulting in CD4 accumulation in primary endosomes. Knockdown of ?1A, another subunit of AP-1, resulted in decreased cellular levels of ?1 and ?2 and, compromising the efficient CD4 degradation by Nef. Moreover, upon artificially stabilizing ESCRT-I in early endosomes, via overexpression of HRS, internalized CD4 accumulates in enlarged HRS-GFP positive endosomes, where co-localize with ?2. Together, the results indicate that ?2-adaptin is a molecule that is essential for CD4 targeting by Nef to ESCRT/MVB pathway, being an important protein in the endo-lysosomal system. Furthermore, the results indicate that ?-adaptins isoforms not only have different functions, but also seem to compose AP-1 complex with distinct cell functions, and only the AP-1 variant comprising ?2, but not ?1, acts in the CD4 down-regulation induced by Nef. These studies contribute to a better understanding on the molecular mechanisms involved in Nef activities, which may also help to improve the understanding of the HIV pathogenesis and the related syndrome. In addition, this work contributes with the understanding of primordial process regulation on intracellular trafficking of transmembrane proteins.
50

O envolvimento da proteína adaptadora 1 (AP-1) no mecanismo de regulação negativa do receptor CD4 por Nef de HIV-1 / The involvement of Adaptor Protein 1 (AP-1) on the Mechanism of CD4 Down-regulation by Nef from HIV-1

Lucas Alves Tavares 05 August 2016 (has links)
O Vírus da Imunodeficiência Humana (HIV) é o agente etiológico da Síndrome da Imunodeficiência Adquirida (AIDS). A AIDS é uma doença de distribuição mundial, e estima-se que existam atualmente pelo menos 36,9 milhões de pessoas infectadas com o vírus. Durante o seu ciclo replicativo, o HIV promove diversas alterações na fisiologia da célula hospedeira a fim de promover sua sobrevivência e potencializar a replicação. A rápida progressão da infecção pelo HIV-1 em humanos e em modelos animais está intimamente ligada à função da proteína acessória Nef. Dentre as diversas ações de Nef está a regulação negativa de proteínas importantes na resposta imunológica, como o receptor CD4. Sabe-se que esta ação resulta da indução da degradação de CD4 em lisossomos, mas os mecanismos moleculares envolvidos ainda são totalmente elucidados. Nef forma um complexo tripartite com a cauda citosólica de CD4 e a proteína adaptadora 2 (AP-2), em vesículas revestidas por clatrina nascentes, induzindo a internalização e degradação lisossomal de CD4. Pesquisas anteriores demonstraram que o direcionamento de CD4 aos lisossomos por Nef envolve a entrada do receptor na via dos corpos multivesiculares (MVBs), por um mecanismo atípico, pois, embora não necessite da ubiquitinação de carga, depende da ação de proteínas que compõem os ESCRTs (Endosomal Sorting Complexes Required for Transport) e da ação de Alix, uma proteína acessória da maquinaria ESCRT. Já foi reportado que Nef interage com subunidades dos complexos AP-1, AP-2, AP-3 e Nef não parece interagir com subunidades de AP-4 e AP-5. Entretanto, o papel da interação de Nef com AP-1 e AP-3 na regulação negativa de CD4 ainda não está totalmente elucidado. Ademais, AP-1, AP-2 e AP-3 são potencialmente heterogêneos devido à existência de isoformas múltiplas das subunidades codificadas por diferentes genes. Todavia, existem poucos estudos para demonstrar se as diferentes combinações de isoformas dos APs são formadas e se possuem propriedades funcionais distintas. O presente trabalho procurou identificar e caracterizar fatores celulares envolvidos na regulação do tráfego intracelular de proteínas no processo de regulação negativa de CD4 induzido por Nef. Mais especificamente, este estudo buscou caracterizar a participação do complexo AP-1 na modulação negativa de CD4 por Nef de HIV-1, através do estudo funcional das duas isoformas de ?-adaptina, subunidades de AP-1. Utilizando a técnica de Pull-down demonstramos que Nef é capaz de interagir com ?2. Além disso, nossos dados de Imunoblot indicaram que a proteína ?2-adaptina, e não ?1-adaptina, é necessária no processo de degradação lisossomal de CD4 por Nef e que esta participação é conservada para degradação de CD4 por Nef de diferentes cepas virais. Ademais, por citometria de fluxo, o silenciamento de ?2, e não de ?1, compromete a diminuição dos níveis de CD4 por Nef da membrana plasmática. A análise por imunofluorêsncia indireta também revelou que a diminuição dos níveis de ?2 impede a redistribuição de CD4 por Nef para regiões perinucleares, acarretando no acúmulo de CD4, retirados por Nef da membrana plasmática, em endossomos primários. A depleção de ?1A, outra subunidade de AP-1, acarretou na diminuição dos níveis celulares de ?2 e ?1, bem como, no comprometimento da eficiente degradação de CD4 por Nef. Além disso, foi possível observar que, ao perturbar a maquinaria ESCRT via super-expressão de HRS (uma subunidade do complexo ESCRT-0), ocorreu um acumulo de ?2 em endossomos dilatados contendo HRS-GFP, nos quais também detectou-se CD4 que foi internalizado por Nef. Em conjunto, os resultados indicam que ?2-adaptina é uma importante molécula para o direcionamento de CD4 por Nef para a via ESCRT/MVB, mostrando ser uma proteína relevante no sistema endo-lisossomal. Ademais, os resultados indicaram que as isoformas ?-adaptinas não só possuem funções distintas, mas também parecem compor complexos AP-1 com diferentes funções celulares, já que apenas a variante AP-1 contendo ?2, mas não ?1, participa da regulação negativa de CD4 por Nef. Estes estudos contribuem para o melhor entendimento dos mecanismos moleculares envolvidos na atividade de Nef, que poderão também ajudar na melhor compreensão da patogênese do HIV e da síndrome relacionada. Em adição, este trabalho contribui para o entendimento de processos fundamentais da regulação do tráfego de proteínas transmembrana no sistema endo-lisossomal. / The Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). AIDS is a disease which has a global distribution, and it is estimated that there are currently at least 36.9 million people infected with the virus. During the replication cycle, HIV promotes several changes in the physiology of the host cell to promote their survival and enhance replication. The fast progression of HIV-1 in humans and animal models is closely linked to the function of an accessory protein Nef. Among several actions of Nef, one is the most important is the down-regulation of proteins from the immune response, such as the CD4 receptor. It is known that this action causes CD4 degradation in lysosome, but the molecular mechanisms are still incompletely understood. Nef forms a tripartite complex with the cytosolic tail of the CD4 and adapter protein 2 (AP-2) in clathrin-coated vesicles, inducing CD4 internalization and lysosome degradation. Previous research has demonstrated that CD4 target to lysosomes by Nef involves targeting of this receptor to multivesicular bodies (MVBs) pathway by an atypical mechanism because, although not need charging ubiquitination, depends on the proteins from ESCRTs (Endosomal Sorting Complexes Required for Transport) machinery and the action of Alix, an accessory protein ESCRT machinery. It has been reported that Nef interacts with subunits of AP- 1, AP-2, AP-3 complexes and Nef does not appear to interact with AP-4 and AP-5 subunits. However, the role of Nef interaction with AP-1 or AP-3 in CD4 down-regulation is poorly understood. Furthermore, AP-1, AP-2 and AP-3 are potentially heterogeneous due to the existence of multiple subunits isoforms encoded by different genes. However, there are few studies to demonstrate if the different combinations of APs isoforms are form and if they have distinct functional properties. This study aim to identify and characterize cellular factors involved on CD4 down-modulation induced by Nef from HIV-1. More specifically, this study aimed to characterize the involvement of AP-1 complex in the down-regulation of CD4 by Nef HIV-1 through the functional study of the two isoforms of ?-adaptins, AP-1 subunits. By pull-down technique, we showed that Nef is able to interact with ?2. In addition, our data from immunoblots indicated that ?2- adaptin, not ?1-adaptin, is required in Nef-mediated targeting of CD4 to lysosomes and the ?2 participation in this process is conserved by Nef from different viral strains. Furthermore, by flow cytometry assay, ?2 depletion, but not ?1 depletion, compromises the reduction of surface CD4 levels induced by Nef. Immunofluorescence microscopy analysis also revealed that ?2 depletion impairs the redistribution of CD4 by Nef to juxtanuclear region, resulting in CD4 accumulation in primary endosomes. Knockdown of ?1A, another subunit of AP-1, resulted in decreased cellular levels of ?1 and ?2 and, compromising the efficient CD4 degradation by Nef. Moreover, upon artificially stabilizing ESCRT-I in early endosomes, via overexpression of HRS, internalized CD4 accumulates in enlarged HRS-GFP positive endosomes, where co-localize with ?2. Together, the results indicate that ?2-adaptin is a molecule that is essential for CD4 targeting by Nef to ESCRT/MVB pathway, being an important protein in the endo-lysosomal system. Furthermore, the results indicate that ?-adaptins isoforms not only have different functions, but also seem to compose AP-1 complex with distinct cell functions, and only the AP-1 variant comprising ?2, but not ?1, acts in the CD4 down-regulation induced by Nef. These studies contribute to a better understanding on the molecular mechanisms involved in Nef activities, which may also help to improve the understanding of the HIV pathogenesis and the related syndrome. In addition, this work contributes with the understanding of primordial process regulation on intracellular trafficking of transmembrane proteins.

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