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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

Characterizing the Biological Functions of Five Shikimate Dehydrogenase Homologs Enzymes in Pseudomonas putida KT2440

Penney, Kathrine 26 November 2012 (has links)
The shikimate pathway links carbohydrate metabolism to biosynthesis of the aromatic amino acids in plants, fungi, bacteria and apicomplexan parasites. The pathway has seven enzymatic steps which convert erythrose-4-phosphate and phosphoenolpyruvate to chorismate, the precursor of tyrosine, tryptophan and phenylalanine. Due to the absence of the pathway in mammalian species, the enzymes are attractive targets for herbicides and antimicrobials. Shikimate dehydrogenase (SDH) catalyses the fourth step, the NADP-dependent reversible reduction of 3-dehydroshikimate to shikimate. Five SDH homologs – AroE, Ael1, YdiB, RifI and SdhL – have been identified through kinetic analysis and phylogenetic studies in the bacterium Pseudomonas putida. SDH homolog gene knockouts (KO) were used to characterize their functions. The AroE KO and Ael1 KO were successfully constructed via gene SOEing of the SDH homolog with a gentamycin antibiotic cassette and homologous recombination via electroporation into WT P. putida KT2440. Preliminary characterization tested KO growth, auxotroph recovery and fluorescent activity.
2

Characterizing the Biological Functions of Five Shikimate Dehydrogenase Homologs Enzymes in Pseudomonas putida KT2440

Penney, Kathrine 26 November 2012 (has links)
The shikimate pathway links carbohydrate metabolism to biosynthesis of the aromatic amino acids in plants, fungi, bacteria and apicomplexan parasites. The pathway has seven enzymatic steps which convert erythrose-4-phosphate and phosphoenolpyruvate to chorismate, the precursor of tyrosine, tryptophan and phenylalanine. Due to the absence of the pathway in mammalian species, the enzymes are attractive targets for herbicides and antimicrobials. Shikimate dehydrogenase (SDH) catalyses the fourth step, the NADP-dependent reversible reduction of 3-dehydroshikimate to shikimate. Five SDH homologs – AroE, Ael1, YdiB, RifI and SdhL – have been identified through kinetic analysis and phylogenetic studies in the bacterium Pseudomonas putida. SDH homolog gene knockouts (KO) were used to characterize their functions. The AroE KO and Ael1 KO were successfully constructed via gene SOEing of the SDH homolog with a gentamycin antibiotic cassette and homologous recombination via electroporation into WT P. putida KT2440. Preliminary characterization tested KO growth, auxotroph recovery and fluorescent activity.
3

Papel de citocinas e da leptina na imunopatologia da fase aguda na infecção experimental pelo trypanosoma cruzi em camundongos nocautes para IL-4 e IFN-γ / The role of cytokines and leptin in immunopathology of acute phase in experimental infection of Trypanosoma cruzi in knockout mice for IL-4 and IFN-γ

Almeida, Vera Lucia Lima de 07 April 2017 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2017-09-26T18:09:59Z No. of bitstreams: 2 Dissertação - Vera Lúcia Lima de Almeida - 2017.pdf: 4171276 bytes, checksum: 87f3a46f53c09bbba2b757e69ce2c7d8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Rejected by Luciana Ferreira (lucgeral@gmail.com), reason: A citação apresenta problemas : Almeida, V. L. L. Papel de citocinas e da leptina na imunopatologia da fase aguda na infecção experimental pelo trypanosoma cruzi em camundongos nocautes para IL-4 e IFN-γ. 2017. 66 f. Dissertação (Mestrado em Medicina Tropical e Saúde Publica) - Universidade Federal de Goiás,Goiânia,2017. CORRETO: ALMEIDA, V. L. L. Papel de citocinas e da leptina na imunopatologia da fase aguda na infecção experimental pelo trypanosoma cruzi em camundongos nocautes para IL-4 e IFN-γ. 2017. 66 f. Dissertação (Mestrado em Medicina Tropical e Saúde Publica) - Universidade Federal de Goiás, Goiânia, 2017. on 2017-09-27T11:28:48Z (GMT) / Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2017-09-27T17:46:52Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação - Vera Lúcia Lima de Almeida - 2017.pdf: 4171276 bytes, checksum: 87f3a46f53c09bbba2b757e69ce2c7d8 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-02T13:43:34Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação - Vera Lúcia Lima de Almeida - 2017.pdf: 4171276 bytes, checksum: 87f3a46f53c09bbba2b757e69ce2c7d8 (MD5) / Made available in DSpace on 2017-10-02T13:43:34Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação - Vera Lúcia Lima de Almeida - 2017.pdf: 4171276 bytes, checksum: 87f3a46f53c09bbba2b757e69ce2c7d8 (MD5) Previous issue date: 2017-04-07 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Chagas disease is a parasitic disease caused by the Protozoan Trypanosoma cruzi. Approximately 30% of infected individuals develop cardiac manifestations. Among the factors involved in this evolution highlights the role of inflammation. Evidence points to an important relationship of adipokines with the cellular immune response and inflammation. The present study is objective is to evaluate the role of cytokines and leptin on immunopathology of acute phase of experimental infection by T. cruzi. For this we used C57Bl/6 WT mice, C57Bl/6 WT KO IFN-γ, Balb-c WT and Balb-c KO IL-4 100 infected with of Colombian strain forms of T. cruzi and non-infected controls was analyzed in the hearts the presence of T. cruzi, fibrosis, inflammatory infiltrate, production of cytokines in situ and serum levels of leptin, TNF-α and IL-10. Noted greater tissue parasitism in C57Bl/6 animals KO IFN-γ, but no difference in the intensity of the inflammatory infiltrate and percentage of fibrosis. Regarding cytokines C57Bl/6 mice IFN-γ KO infected showed increased TNF-α in situ, as well as the Balbc KO IL-4. Despite greater expression in situ, systemically animals Balb-c KO IL-4 have shown to be good producers of TNF-α and IL-10 as well as the C57Bl/6 KO IFNγ. However, these last have shown to be good producers of serum leptin, as well as the Balb-c. Thus, our results indicate that in the absence of IFN-γ mice infected can' not control the tissue parasitism. However, feature increased in situ of TNF-α and serum leptin as a compensatory mechanism of the Th1 response deficiency. / A doença de Chagas é uma doença parasitária causada pelo protozoário Trypanosoma cruzi. Aproximadamente 30% dos indivíduos infectados desenvolvem a manifestação cardíaca. Dentre os fatores envolvidos nesta evolução destaca-se o papel da inflamação. Evidências apontam uma importante relação das adipocitocinas com a resposta imune celular e inflamação. O presente estudo objetivou avaliar o papel de citocinas e da leptina na imunopatologia da fase aguda da infecção experimental pelo T. cruzi. Para isso foram utilizados camundongos C57Bl/6 WT, C57Bl/6 KO IFN-γ, Balb-c WT e Balb-c KO IL-4 infectados com 100 formas tripomastigotas de cepa Colombiana de T. cruzi e controles não infectados. Foi analisado nos corações a presença ninhos de T. cruzi, infiltrado inflamatório, fibrose, produção de citocinas in situ e níveis séricos de leptina, TNF-α e IL-10. Foi observado maior parasitismo tissular nos animais C57Bl/6 KO IFN-γ, mas sem diferença na intensidade do infiltrado inflamatório e percentual de fibrose. Em relação as citocinas os camundongos C57Bl/6 KO IFN-γ infectados apresentaram aumento de TNF-α in situ, assim como os Balb-c KO IL-4. Apesar de maior expressão in situ, sistemicamente os animais Balb-c KO IL-4 não mostram ser bons produtores de TNF-α e IL-10 assim como os C57Bl/6 KO IFN-γ, entretanto esses últimos mostraram ser bons produtores de leptina sérica, assim como os Balb-c. Dessa forma, nossos resultados apontam que na ausência de IFN-γ os camundongos infectados não conseguem controlar o parasitismo tissular. Entretanto apresentam aumento in situ de TNF-α e leptina sérica como mecanismo compensatório da deficiência de resposta Th1, representado pela ausência de IFN-γ.
4

Investigations of lipid metabolism in Yarrowia lipolytica

Blocher-Smith, Ethan Charles 31 July 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / An investigation of the lipid metabolism pathway in the yeast Yarrowia lipolytica was conducted. Yarrowia is an oleaginous ascomycete that is capable of growing on many different substrates, which derives its name from its high efficiency of growth on lipids. Once the exogenous lipids are converted into free fatty acids and internalized by the yeast, the primary mode of degradation is through β-oxidation mediated by the peroxisomal oxidases, or POX genes. These enzymes catalyze the formation of a trans double bond, producing the trans-2-enoyl product. Our study looked at the comparison of the Y. lipolytica prototrophic strain against a knockout of the Pox2 gene on the uptake, incorporation, and degradation of relevant fatty acids. To construct this gene knockout, a novel gene deletion method using a combination of Cre recombinase and the AHAS* gene was synthesized, developed, and tested successfully. This knockout system allows for serial deletion of genes with the use of only one resistance marker, with excision of the marker after selection.

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