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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

Studies on the 5' non-coding region of the genome of poliovirus

Sullivan, Michael A. January 1992 (has links)
The last decade has seen widespread application of recombinant DNA technology to the study of picornaviruses. Comparative sequence analysis has revealed that the most highly conserved region amongst many members of this family of viruses is the 5' non-coding region. Using recombinant type 3 polioviruses it has been shown that a single point mutation located in this region dramatically reduces neurovirulence and inhibits the intracellular life-cycle of the virus. Mutation at this nucleotide contributes to the observed reversion to neurovirulence of the Sabin attenuated poliovirus type 3 vaccine strain currently used in vaccination programmes throughout the world. Knowledge concerning the function of the 5' non-coding region remains scant, and as a result, the mechanism whereby a single point mutation within this region results in alteration of the expressed phenotype of the virus remains unknown. Clearly, an understanding of the molecular mechanism(s) involved requires greater knowledge of the function of the 5' non-coding region. This thesis describes the design and construction of vectors that allow analysis of the role of the 5' non-coding region in the control of viral translation, replication, and encapsidation of viral RNA. In the plasmid pRSV-5'polio-CATm2 (N+), the 5' non-coding region of poliovirus was fused to the coding region of the bacterial chloramphenicol acetyltransferase reporter gene. The presence of the 5' non-coding region resulted in the inhibition of CAT expression when this plasmid was introduced into eukaryotic cells in culture. Deletion analysis of the 5' non-coding region in this vector identified two regions that were responsible for the marked inhibition of expression of the reporter gene. It would appear from the results of these experiments that the poliovirus/CAT chimaeric message is translatsed as a normal eukaryotic mRNA and is subject to the rules of the "scanning model". This observation suggests that the 5' non-coding region of poliovirus on its own does not possess features which enable a message containing it to be translated efficiently. It is concluded that a second factor, present in infected cells, is required for the efficient translation of poliovirus. A second plasmid was designed and constructed to investigate the role of the 5' non-coding region in replication and encapsidation of viral RNA. Preliminary data suggest that the product of this vector does undergo replication while its ability to be encapsidated has still to be tested.
2

The identification of aptamers against serum biomarkers of human tuberculosis

Martin, Darius Riziki January 2018 (has links)
>Magister Scientiae - MSc / Tuberculosis (TB) is a global health problem and rated as the second leading cause of death after HIV/AIDS. Transmission of TB from one person to the next is very rapid in crowded communities. Therefore, it is crucial to identify people who are infected as quickly as possible not only to provide treatment but also to prevent the spread of the disease. Current TB diagnostic tests such as the culture and sputum smear tests are time-consuming, while rapid tests make use of antibodies that are costly and have low sensitivity and stability. Great improvement has been observed when aptamers are used in place of antibodies in rapid diagnostic tests such as lateral flow devices (LFDs). Therefore, the current study aims to synthesize and identify aptamers against serum biomarkers for development of rapid TB diagnostic tests such as a lateral flow assay. Several TB serum biomarkers have been identified and can be used for the diagnosis of TB. TB biomarkers expressed in serum samples were identified through in silico approach. The biomarkers were expressed in bacterial systems using recombinant DNA technology. The recombinant proteins were purified by affinity chromatography and further used as targets for the selection of aptamers using Systemic Evolution of Ligands by EXponential enrichment (SELEX). Aptamers for the selected biomarkers were synthesized based on magnetic-bead based SELEX and characterized by electrophoretic mobility shift assay (EMSA), Surface Plasmon resonance (SPR) and MicroScale Thermophoresis (MST). Six putative TB serum biomarker proteins were selected from literature, namely, Insulin-like Growth Factor Binding Protein 6 (IGFBP6), Interferon-stimulated Gene 15 (ISG15), Calcium Binding Protein (S100A9), Retinol Binding Protein 4 (RBP4), Granzyme A (GrA), and Transgelin-2 (TAGLN2). The biomarkers were recombinantly expressed and purified after which they were used as targets in SELEX for aptamers synthesis. Aptamers were analysed by in silico method and the ones with highly conserved motifs were selected. The selected aptamers were synthesized and later characterized. The aptamers that show high affinity and specificity for the biomarkers will be used for the fabrication of a rapid lateral flow device for TB screening. Such a test would allow for a short diagnostic turnaround time, and hence expedite treatment.
3

Gene technology at stake : Swedish governmental commissions on the border of science and politics

Eklöf, Jenny January 2007 (has links)
<p>This thesis examines the Swedish political response to the challenges posed by gene technology, seen through the prism of governmental commissions. It discerns and analyses continuities and changes in the Swedish political conception of gene technology, over the course of two decades, 1980–2000. This is done by thematically following ideas of “risks” and “ethics” as they are represented in the inner workings and reception of three governmental commissions. The Gene-Ethics Commission (1981–1984), the Gene Technology Commission (1990–1992) and the Biotechnology Commission (1997–2000) form the empirical focal points of this analysis. The first two provided preparatory policy proposals that preceded the implementation of the Swedish gene technology laws of 1991 and 1994. The last one aimed at presenting a comprehensive Swedish biotechnology policy for the new millennium.</p><p> The study takes into account the role of governmental commissions as arenas where science and politics intersect in Swedish political life, and illuminates how this type of “boundary organisation”, placed on the border of science and politics, impinges on the understanding of the gene technology issue. The commissions have looked into the limits, dangers, possibilities and future applications of gene technology. They have been appointed to deal with the problematic task of distinguishing between what is routine and untested practices, realistic prediction and “science fiction”, what are unique problems and what are problems substantially similar to older ones, what constitutes a responsible approach as opposed to misconduct and what it means to let things “get out of hand” in contrast to being “in control”. Throughout a period of twenty years, media reports have continued to frame the challenges posed by gene technology as a task of balancing risks and benefits, walking the fine line between “frankenfoods” and “miracle drugs”. </p><p>One salient problem for the commissions to solve was that science and industry seemed to promote a technology the public opposed and resisted, at least in parts. For both politics and science to gain, or regain, public trust it needed to demonstrate that risks – be it environmental, ethical or health related ones – were under control. Under the surface, it was much more complicated than “science helping politics” to make informed and rational decisions on how to formulate a regulatory policy. Could experts be trusted to participate in policy-making in a neutral way and was it not important, in accordance with democratic norms, to involve the public? </p>
4

Construção e análise funcional de vetores lentivirais de interesse biotecnológico / Construction and functional analysis of lentiviral vectors for biotechnological purposes

Vedoveli, Naiara Cristina Pulzi Saito 16 May 2016 (has links)
Vetores lentivirais são ferramentas fundamentais para modificação celular. Sua utilização ganhou destaque devido à capacidade desses em integrar ao genoma de células que estão ou não em divisão. Grande parte dos vetores desenvolvidos são derivados do genoma do Vírus da Imunodeficiência Humana (HIV-1), portanto, modificações foram necessárias a fim de evitar a formação de Partículas Competentes em Replicação (RCLs) e garantir uma utilização segura. Com as modificações, foram produzidos os vetores lentivirais de terceira geração utilizados atualmente. Esses vetores podem ser usados para expressão constitutiva de genes, produção de proteínas recombinantes, produção de animais transgênicos e terapia gênica. Com isso, torna-se necessário o desenvolvimento de vetores lentivirais para aplicação em pesquisa básica e ensaios clínicos. Dessa forma, o presente estudo teve por objetivo a construção de vetores de expressão lentivirais aplicáveis à: 1- expressão constitutiva de genes de interesse e 2-vetores com promotores específicos para expressão de proteínas em megacariócitos. Esse trabalho descreve a construção desses vetores, sua importância e discute suas possíveis aplicações. As sequências selecionadas para produção dos vetores foram: os genes Runx1C e VkorC1 e os promotores proPF4 e proITGA2b. Todas as sequências encontram-se clonadas em vetor de clonagem e estoques de bactérias com esses vetores congeladas em glicerol foram confeccionados. Para a confecção dos vetores lentivirais, o gene Runx1C foi subclonado no vetor lentiviral base p1054-CIGWS sob controle do promotor forte CMV, enquanto o promotor proITGA2b foi subclonado no vetor base p1054-FVIII, em substituição ao promotor CMV, de forma a controlar a expressão de FVIII. Os dois vetores produzidos apresentam ainda o gene para proteína verde GFP precedida do sítio de ligação do ribossomo IRES, com expressão controlada pelo mesmo promotor interno do vetor. O trabalho possibilitou, portanto, a produção de dois vetores lentivirais bi-cistrônicos: p1054-Runx1C e pL-proITGA2b-FVIII. A construção p1054-Runx1C ainda não foi sequenciada, mas foi confirmada por restrição enzimática e apresenta potencial para aplicação em estudos de diferenciação hematopoética. Já a construção pL-proITGA2b-FVIII foi sequenciada, porém sem confirmação da região de ligação do proITGA2b ao vetor. Reações de PCR e de restrição enzimática confirmaram a ligação e sequenciamento mostrou 67% de similaridade entre a região sequenciada e o promotor ITGA2b depositado no banco de dados. Análise funcional foi realizada através da transfecção desse vetor em células HEK-293T. As células transfectadas apresentaram expressão positiva para GFP e secreção de FVIII no sobrenadante celular, evidenciando que o promotor proITGA2b clonado no vetor encontra-se ativo. Esse vetor apresenta potencial para aplicação em terapia gênica para hemofilias, pois apresenta expressão do fator de coagulação direcionado a megacariócitos e plaquetas, células que estão diretamente relacionadas ao processo de coagulação, representando grandes veículos para secreção desses fatores. Ainda, os dois vetores lentivirais gerados apresentam segurança e eficiência elevadas, pois são vetores de terceira geração auto-inativantes (SIN) e apresentam elementos regulatórios que melhoram o transporte e integração do DNA ao genoma hospedeiro. / Lentiviral vectors are fundamental tools for cell modification that gained prominence due to their ability to integrate the genome of non-dividing cells. Most of developed lentiviral vectors are derived from the genome of Human Immunodeficiency Virus (HIV-1), so modifications were necessary in order to avoid the formation of Competent Replication Particles (RCLs) and ensure safer operations. The modifications led to development of third generation lentiviral vectors currently used. These vectors can be used for constitutive gene expression, production of recombinant protein, production of transgenic animals and gene therapy. It\'s evident the need to develop lentiviral vectors for application in basic research and clinical trials. Thus this study aimed to construct lentiviral expression vectors applicable to: 1- constitutive expression of genes of interest and 2-vectors with specific promoters for expression of proteins in megakaryocytes and platelets. This paper describes the construction of these vectors, their importance and discuss their possible applications. Sequences were selected for production of the vectors: genes Runx1C and VkorC1 and proPF4 and proITGA2b promoters. All four sequences are cloned into cloning vectors and stocks of bacteria with these vectors frozen in glycerol were prepared. Lentiviral vectors were engineered from subcloning the sequence Runx1C into the basic lentiviral vector p1054- CIGWS under control of the strong CMV promoter, and from subcloning proITGA2b promoter into p1054-FVIII basic vector, replacing the CMV promoter in order to control the expression of FVIII. Both vectors exhibit the green fluorescence protein GFP gene preceded by a ribosome binding site IRES under control of vector\'s internal promoter. Therefore, this work resulted in the production of two bi-cistronic lentiviral vectors: p1054-Runx1C and pLproITGA2b-FVIII. The p1054-Runx1C construction has not yet been sequenced, but it was confirmed by digestion and has potential for use in hematopoietic differentiation studies. Though, pL-proITGA2b-FVIII construct was sequenced, but the technique didn\'t allow to confirm the binding region between proITGA2b and the vector. Although PCR reaction and digestion confirmed the construction. Sequence analysis showed 67% similarity between the sequenced region and ITGA2b promoter deposited in the database. Functional analysis was performed by transfection of this vector in HEK-293T cells. The transfected cells showed positive expression of GFP and FVIII secretion in cell supernatant, indicating that the proITGA2b promoter cloned into the vector is active. This vector has potential usage in gene therapy for hemophilia, since it can be used to express coagulation factors in megakaryocytes and platelets and these cells are directly related to the clotting process, representing great vehicles for secretion of these factors. Even more, the two lentiviral vectors generated have higher safety and efficiency, as they are self-inactivating (SIN) third-generation vectors and have regulatory elements that enhance transport and integration of DNA into the host genome.
5

Construção e análise funcional de vetores lentivirais de interesse biotecnológico / Construction and functional analysis of lentiviral vectors for biotechnological purposes

Naiara Cristina Pulzi Saito Vedoveli 16 May 2016 (has links)
Vetores lentivirais são ferramentas fundamentais para modificação celular. Sua utilização ganhou destaque devido à capacidade desses em integrar ao genoma de células que estão ou não em divisão. Grande parte dos vetores desenvolvidos são derivados do genoma do Vírus da Imunodeficiência Humana (HIV-1), portanto, modificações foram necessárias a fim de evitar a formação de Partículas Competentes em Replicação (RCLs) e garantir uma utilização segura. Com as modificações, foram produzidos os vetores lentivirais de terceira geração utilizados atualmente. Esses vetores podem ser usados para expressão constitutiva de genes, produção de proteínas recombinantes, produção de animais transgênicos e terapia gênica. Com isso, torna-se necessário o desenvolvimento de vetores lentivirais para aplicação em pesquisa básica e ensaios clínicos. Dessa forma, o presente estudo teve por objetivo a construção de vetores de expressão lentivirais aplicáveis à: 1- expressão constitutiva de genes de interesse e 2-vetores com promotores específicos para expressão de proteínas em megacariócitos. Esse trabalho descreve a construção desses vetores, sua importância e discute suas possíveis aplicações. As sequências selecionadas para produção dos vetores foram: os genes Runx1C e VkorC1 e os promotores proPF4 e proITGA2b. Todas as sequências encontram-se clonadas em vetor de clonagem e estoques de bactérias com esses vetores congeladas em glicerol foram confeccionados. Para a confecção dos vetores lentivirais, o gene Runx1C foi subclonado no vetor lentiviral base p1054-CIGWS sob controle do promotor forte CMV, enquanto o promotor proITGA2b foi subclonado no vetor base p1054-FVIII, em substituição ao promotor CMV, de forma a controlar a expressão de FVIII. Os dois vetores produzidos apresentam ainda o gene para proteína verde GFP precedida do sítio de ligação do ribossomo IRES, com expressão controlada pelo mesmo promotor interno do vetor. O trabalho possibilitou, portanto, a produção de dois vetores lentivirais bi-cistrônicos: p1054-Runx1C e pL-proITGA2b-FVIII. A construção p1054-Runx1C ainda não foi sequenciada, mas foi confirmada por restrição enzimática e apresenta potencial para aplicação em estudos de diferenciação hematopoética. Já a construção pL-proITGA2b-FVIII foi sequenciada, porém sem confirmação da região de ligação do proITGA2b ao vetor. Reações de PCR e de restrição enzimática confirmaram a ligação e sequenciamento mostrou 67% de similaridade entre a região sequenciada e o promotor ITGA2b depositado no banco de dados. Análise funcional foi realizada através da transfecção desse vetor em células HEK-293T. As células transfectadas apresentaram expressão positiva para GFP e secreção de FVIII no sobrenadante celular, evidenciando que o promotor proITGA2b clonado no vetor encontra-se ativo. Esse vetor apresenta potencial para aplicação em terapia gênica para hemofilias, pois apresenta expressão do fator de coagulação direcionado a megacariócitos e plaquetas, células que estão diretamente relacionadas ao processo de coagulação, representando grandes veículos para secreção desses fatores. Ainda, os dois vetores lentivirais gerados apresentam segurança e eficiência elevadas, pois são vetores de terceira geração auto-inativantes (SIN) e apresentam elementos regulatórios que melhoram o transporte e integração do DNA ao genoma hospedeiro. / Lentiviral vectors are fundamental tools for cell modification that gained prominence due to their ability to integrate the genome of non-dividing cells. Most of developed lentiviral vectors are derived from the genome of Human Immunodeficiency Virus (HIV-1), so modifications were necessary in order to avoid the formation of Competent Replication Particles (RCLs) and ensure safer operations. The modifications led to development of third generation lentiviral vectors currently used. These vectors can be used for constitutive gene expression, production of recombinant protein, production of transgenic animals and gene therapy. It\'s evident the need to develop lentiviral vectors for application in basic research and clinical trials. Thus this study aimed to construct lentiviral expression vectors applicable to: 1- constitutive expression of genes of interest and 2-vectors with specific promoters for expression of proteins in megakaryocytes and platelets. This paper describes the construction of these vectors, their importance and discuss their possible applications. Sequences were selected for production of the vectors: genes Runx1C and VkorC1 and proPF4 and proITGA2b promoters. All four sequences are cloned into cloning vectors and stocks of bacteria with these vectors frozen in glycerol were prepared. Lentiviral vectors were engineered from subcloning the sequence Runx1C into the basic lentiviral vector p1054- CIGWS under control of the strong CMV promoter, and from subcloning proITGA2b promoter into p1054-FVIII basic vector, replacing the CMV promoter in order to control the expression of FVIII. Both vectors exhibit the green fluorescence protein GFP gene preceded by a ribosome binding site IRES under control of vector\'s internal promoter. Therefore, this work resulted in the production of two bi-cistronic lentiviral vectors: p1054-Runx1C and pLproITGA2b-FVIII. The p1054-Runx1C construction has not yet been sequenced, but it was confirmed by digestion and has potential for use in hematopoietic differentiation studies. Though, pL-proITGA2b-FVIII construct was sequenced, but the technique didn\'t allow to confirm the binding region between proITGA2b and the vector. Although PCR reaction and digestion confirmed the construction. Sequence analysis showed 67% similarity between the sequenced region and ITGA2b promoter deposited in the database. Functional analysis was performed by transfection of this vector in HEK-293T cells. The transfected cells showed positive expression of GFP and FVIII secretion in cell supernatant, indicating that the proITGA2b promoter cloned into the vector is active. This vector has potential usage in gene therapy for hemophilia, since it can be used to express coagulation factors in megakaryocytes and platelets and these cells are directly related to the clotting process, representing great vehicles for secretion of these factors. Even more, the two lentiviral vectors generated have higher safety and efficiency, as they are self-inactivating (SIN) third-generation vectors and have regulatory elements that enhance transport and integration of DNA into the host genome.
6

Gene technology at stake : Swedish governmental commissions on the border of science and politics

Eklöf, Jenny January 2007 (has links)
This thesis examines the Swedish political response to the challenges posed by gene technology, seen through the prism of governmental commissions. It discerns and analyses continuities and changes in the Swedish political conception of gene technology, over the course of two decades, 1980–2000. This is done by thematically following ideas of “risks” and “ethics” as they are represented in the inner workings and reception of three governmental commissions. The Gene-Ethics Commission (1981–1984), the Gene Technology Commission (1990–1992) and the Biotechnology Commission (1997–2000) form the empirical focal points of this analysis. The first two provided preparatory policy proposals that preceded the implementation of the Swedish gene technology laws of 1991 and 1994. The last one aimed at presenting a comprehensive Swedish biotechnology policy for the new millennium. The study takes into account the role of governmental commissions as arenas where science and politics intersect in Swedish political life, and illuminates how this type of “boundary organisation”, placed on the border of science and politics, impinges on the understanding of the gene technology issue. The commissions have looked into the limits, dangers, possibilities and future applications of gene technology. They have been appointed to deal with the problematic task of distinguishing between what is routine and untested practices, realistic prediction and “science fiction”, what are unique problems and what are problems substantially similar to older ones, what constitutes a responsible approach as opposed to misconduct and what it means to let things “get out of hand” in contrast to being “in control”. Throughout a period of twenty years, media reports have continued to frame the challenges posed by gene technology as a task of balancing risks and benefits, walking the fine line between “frankenfoods” and “miracle drugs”. One salient problem for the commissions to solve was that science and industry seemed to promote a technology the public opposed and resisted, at least in parts. For both politics and science to gain, or regain, public trust it needed to demonstrate that risks – be it environmental, ethical or health related ones – were under control. Under the surface, it was much more complicated than “science helping politics” to make informed and rational decisions on how to formulate a regulatory policy. Could experts be trusted to participate in policy-making in a neutral way and was it not important, in accordance with democratic norms, to involve the public?

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