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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.
1

The Functional Roles of the Human Immunodeficiency Virus Type-1 Matrix Protein during Viral Life Cycle: A Dissertation

Dupont, Stefan A. 02 August 2000 (has links)
The human immunodeficiency virus type-1 matrix (HIV-1 MA) is best described as a multi-functional, structural protein. However, the multitude of functional activities ascribed to this viral component is not nearly as interesting as are its seemingly paradoxical and opposing roles during the viral life cycle. At the time of virus infection, HIV-1 MA remains associated with the reverse transcription complex, in which viral nucleic acids are synthesized, and facilitates its translocation to the host cell nucleus (Bukrinsky, Sharova et al. 1992; Bukrinsky, Sharova et al. 1993). This activity of MA has been proposed to form the basis for the infection of non-dividing cells (Bukrinsky, Haggerty et al. 1993). An interaction between the C-terminally phosphorylated form of MA and HIV-1 integrase, an integral component of the complex, was initially proposed to mediate this association (Gallay, Swingler et al. 1995; Gallay, Swingler et al. 1995). However, conditions which promote dissociation of integrase from the reverse transcription complex do not reduce MA association (Miller, Farnet et al. 1997). The possibility of a direct interaction between MA and the viral genome is discussed in Chapter III. The nucleophilic nature of HIV-1 MA is paradoxical with its reported activity in targeting the viral precursor proteins to the cytoplasmic membrane (Krausslich and Welker 1996), during the particle production phase of the viral life cycle. Furthermore, MA when expressed in the absence of other viral proteins exhibits a cytoplasmic localization (Fouchier, Meyer et al. 1997); a result which does not support a nuclear translocation role for this protein. The work presented here resolves this seemingly controversial issue. We demonstrate that MA exhibits a strong nuclear export activity. This newly discovered activity is designed to effectively counteract the protein's innate nucleophilic nature, thus maintaining a cytoplasmic localization. The nuclear export function of MA is sensitive to changes within the conformation of the protein as C- and N-terminal deletions, as well as point mutations in the protein, abolish the activity. Furthermore, the export activity is mediated by the Crm1 NES receptor (Fornerod, Ohno et al. 1997; Fukuda, Asano et al. 1997; Ossareh-Nazari, Bachelerie et al. 1997) despite the lack of a leucine-rich export signal within the matrix coding region. Therefore, the interaction between matrix protein and Crm1 is most likely to be mediated by another, perhaps cellular, protein. Any changes in matrix structure may lead to the disruption of this protein-protein interaction. We discuss a model implicating a phosphorylation event in the inactivation of this nuclear export signal. An even more fascinating issue regards the role of this nuclear export activity, during the viral life cycle, and is detailed in Chapter II. In short, mutations in MA which impair its nuclear export activity result in nuclear accumulation of the precursor Gag polyprotein (Pr55) and the nucleocapsid-associated viral genomic RNA. As a result, non-infectious virions deficient in genomic viral RNA are produced. Therefore, drugs designed to block this export activity can undermine the carefully orchestrated course of events during HIV replication and can shut down the growth of the virus.
2

How far away are the CEECs from the EU economic standards? A data envelopment analysis of the economic performance of the CEECs.

Breuss, Fritz, Luptácik, Mikulás, Mahlberg, Bernhard January 2000 (has links) (PDF)
In October 1999 the European Commission published the second progress report on the state of convergence of the Central- and Eastern European candidate countries (CEECs). The report encompasses an assessment, which is based on the three Copenhagen criteria. From an economic point of view, a country must have a functioning market economy and be able to withstand the competition on the European single market. In this paper we present a synthetic performance measure which helps to assess the economic preparedness of the ten Central and Eastern European Countries (CEECs) to become members of the European Union (EU). With the aid of the Data Envelopment Analysis (DEA) we construct a best practice frontier, which is supported by the best performing EU-countries and which serves as a benchmark for the candidate countries. The preparedness of any CEEC is measured as the relative distance to this frontier. The results confirm that the macroeconomic performance of most of the CEECs lies far behind the EU standards, in foreign trade some of the CEECs already perform better than some EU countries. Interestingly, we find out that some CEECs are already better prepared for the EMU than many EU member states. (authors' abstract) / Series: EI Working Papers / Europainstitut
3

The involvement of Hippo Pathway in the physiology and pathophysiology of ovulation in cows

Corrêa Dos Santos, Esdras 04 1900 (has links)
L'ovulation est le processus de rupture du follicule ovarien qui conduit à la libération d'un ovocyte dans l'oviducte pour la fécondation. Le processus ovulatoire est initié par un pic de LH qui conduit à l'activation du récepteur EGF (EGFR) dans les cellules de la granulosa (CG) qui stimule par conséquent l'expression de plusieurs gènes pré-ovulatoires essentiels. Environ 15% de l'infertilité chez les vaches est due à la présence de kystes ovariens qui se développent normalement à partir de follicules pré-ovulatoires qui n'ovulent pas. Chez les femmes et les rongeurs, alors que l'activité physiologique des effecteurs de signalisation Hippo semble essentielle pour la signalisation de l'EGF dans les CG, leur dérégulation peut jouer un rôle important dans les troubles kystiques anovulatoires. À notre connaissance, aucune étude n'a rapporté les rôles physiologiques ou physiopathologiques des effecteurs de la voie Hippo liés à l'ovulation ou à la formation de kystes ovariens chez les bovins. Les principaux objectifs de la présente thèse étaient donc (1) d'élucider l'importance de l'activité physiologique des effecteurs de signalisation Hippo dans la cascade pré-ovulatoire et dans l'ovulation chez les ruminants, et (2) de déterminer si la dérégulation de YAP dans le CG bovin est impliquée dans la pathogenèse de la maladie kystique des ovaires (MKO). Les résultats sont séparés en 2 articles. Dans le premier article, nous avons d'abord utilisé un système de culture de CG préovulatoire bien défini pour montrer que la signalisation YAP est essentielle pour l'expression de l'EGFR et des gènes cibles en aval EREG, EGR1 et TNFAIP6. Plus important encore, en utilisant un système d'injection folliculaire guidée par ultrasons, nous avons également montré que l'inhibiteur classique de la signalisation Hippo, la vertéporfine, inhibe l'ovulation induite par la GnRH in vivo chez les bovins. Dans le deuxième article, nous avons utilisé un modèle bovin de MKO spontanée pour montrer que l'abondance de l'ARNm et des protéines de YAP est significativement plus élevée dans les cellules de la granulosa et de la thèque (CT) isolées des follicules kystiques (structures folliculaires d'au moins 20 mm de diamètre) par rapport aux types de cellules respectifs isolés à partir de grands follicules non kystiques (≥12 mm). De plus, le schéma de phosphorylation de YAP et l'abondance accrue d'ARNm codant pour les gènes cibles YAP-TEAD classiques suggèrent que l'activité transcriptionnelle de YAP est augmentée dans les CG des kystes folliculaires par rapport aux grands follicules non kystiques. Ensemble, ces résultats montrent pour la première fois que la voie Hippo est essentielle à la cascade ovulatoire chez les bovins et que sa dérégulation peut jouer un rôle clé dans la pathogenèse de la maladie kystique des ovaires chez cette espèce. / Ovulation is the process of rupture of the ovarian follicle, which leads to the release of an oocyte into the oviduct for fertilization. The ovulatory process is initiated by a surge of LH that leads to the activation of the EGF receptor (EGFR) in granulosa cells (GC) which consequently stimulates the expression of several essential ovulatory genes. About 15% of infertility in cows is due to the presence of ovarian cysts that generally develop from pre-ovulatory follicles that fail to ovulate. In women and rodents, in addition to the essential physiological activity of Hippo signalling effectors for the EGF signalling in GC, their deregulation also plays an important role in anovulatory cystic disorders. To the best of our knowledge, no studies report physiological or pathophysiological roles of Hippo pathway effectors related to ovulation or ovarian cyst formation in cattle. The main objectives of the present thesis were, therefore, (1) to elucidate the importance of the physiological activity of Hippo signaling effectors in the pre-ovulatory cascade and in ovulation in ruminants and (2) to determine whether dysregulation of YAP in bovine GC is implicated in the pathogenesis of the cystic ovarian disease (COD). The results are separated into 2 articles. In the first article, we employed a well-defined preovulatory GC culture system to show that YAP signaling is essential for expressing EGFR and the downstream target genes EREG, EGR1 and TNFAIP6. Most importantly, using an ultrasound-guided follicular injection system, we have also shown that the classic Hippo signaling inhibitor verteporfin inhibits GnRH-induced ovulation in vivo in cattle. In the second article, we employed a bovine model of spontaneous COD to show that YAP mRNA and protein abundance are significantly higher in granulosa and theca (TC) cells isolated from cystic follicles (follicular structures of at least 20 mm in diameter) compared to the respective cell types isolated from large non-cystic follicles (≥12 mm). Moreover, the phosphorylation pattern of YAP and the increased abundance of mRNA encoding classical YAP-TEAD target genes suggest that the transcriptional activity of YAP is increased in GC of follicular cysts compared to large non-cystic follicles. Together, these results show for the first time that the Hippo pathway is critical to the ovulatory cascade in cattle and its dysregulation may play a key role in the pathogenesis of cystic ovarian disease in this species.
4

The finance-dominated accumulation regime, income distribution and the present crisis

Stockhammer, Engelbert January 2009 (has links) (PDF)
The paper discusses the interactions of changes in income distribution and the accumulation dynamics in the post-Fordist accumulation regime in OECD countries, which is characterized by deregulated financial markets. The neoliberal mode of regulation came with a decisive shift in power relations at the expense of labor, which is clearly reflected in the fall of wage shares across OECD economies. The notion of a "finance-dominated" accumulation regime is proposed to highlight that financial developments crucially shape the pattern and the pace of accumulation. Financial globalization has relaxed balance of payment constraints and thereby allowed the build up of big international imbalances. The combination of real wage moderation and financial liberalization has led to different strategies (or at least outcomes) in different countries. While some countries (like the USA) exhibit a credit-fuelled consumption-driven growth model that comes with large current account deficits, others (like Germany and Japan) show an export-driven growth model with modest consumption growth and large current account surpluses. Overall the finance-dominated accumulation regime is characterized by a mediocre growth performance and by a high degree of fragility. (author´s abstract) / Series: Department of Economics Working Paper Series

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