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As enzimas desempenham papéis essenciais no metabolismo celular. A ausência ou inativação delas podem trazer sérios prejuízos para o desempenho fisiológico de um organismo. Algumas enzimas são comuns a todos os organismos, outras, por sua vez, podem estar ausentes em determinados grupos biológicos, o que pode representar um excelente ponto de partida para estudos bioquímicos que objetivam o desenvolvimento de fármacos mais efetivos. Nesse sentido, é destacado neste trabalho um grupo de enzimas conhecidas como Old Yellow Enzyme (OYE), que são comumente encontradas em bactérias, leveduras, plantas, protozoários, mas estão ausentes em mamíferos. Conhecer a relação estrutura-função dessas proteínas pode trazer alternativas para tratamentos de doenças nas quais o agente etiológico depende da funcionalidade de uma OYE. Dessa forma, doenças negligenciadas, como as leishmanioses e doença de Chagas tornam-se um alvo interessante para o estudo dessas proteínas. Já foi demonstrado o papel que a OYE de Trypanosoma cruzi (TcOYE) desempenha no metabolismo das prostaglandinas, contudo, os dados sobre o comportamento dessas enzimas frente a vários compostos descritos como substratos e a descrição do papel fisiológico dessas proteínas não é completamente compreendido. Além disso, não há informações estruturais e funcionais sobre a OYE de Leishmania braziliensis (LbOYE) na literatura. Assim, um dos principais objetivos desse trabalho de doutorado foi determinar parâmetros estruturais e funcionais das proteínas LbOYE e TcOYE e analisá-los de forma comparativa. Os resultados apresentados sugerem que a LbOYE foi obtida em sua forma enovelada e que a mesma apresenta uma forma sutilmente mais alongada que sua ortóloga TcOYE. Adicionalmente, os resultados também mostram que a proteína LbOYE apresenta menor estabilidade estrutural e maior flexibilidade comparada à TcOYE. Os ensaios de prospecção de ligantes apresentados nesse trabalho mostraram que as enzimas foram obtidas em sua forma funcional e que o composto menadiona foi o que apresentou menor afinidade de interação dentre os compostos avaliados. Além disso, testes de atividade enzimática em baixa pressão de oxigênio com a proteína TcOYE se mostraram efetivos para determinação de moduladores da atividade funcional da proteína. Este trabalho é pioneiro na caracterização estrutural e funcional da LbOYE. / Enzymes play key roles in cellular metabolism. The absence or inactivation of them can cause serious damage to the physiological performance of an organism. Some enzymes are common to all organisms; others, in turn, may be absent in certain biological groups, which may represent an excellent starting point for biochemical studies aiming at the development of more effective drugs. In this sense, it is highlighted in this work a group of enzymes known as Old Yellow Enzyme (OYE), which are commonly found in bacteria, yeasts, plants, protozoa, but are absent in mammals. Knowing the structure-function relationship of these proteins may provide alternatives for treatments of diseases in which the etiological agent depends on the functionality of an OYE. Thus, neglected diseases such as leishmaniasis and Chagas\' disease become an interesting target for the study of these proteins. However, the role that Trypanosoma cruzi OYE (TcOYE) plays in the metabolism of prostaglandins has been demonstrated, however, data on the behavior of these enzymes against various compounds described as substrates and description of the physiological role of these proteins is not fully understood. In addition, there is no structural and functional information on the OEE of Leishmania braziliensis (LbOYE) in the literature. Thus, one of the main objectives of this doctoral project was to determine structural and functional parameters of LbOYE and TcOYE proteins and to analyze them in a comparative way. The presented results suggest that the LbOYE was obtained in its endovelada form and that it presents a subtly more elongated form than its ortholog TcOYE. In addition, the results also show that the LbOYE protein presents lower structural stability and greater flexibility compared to TcOYE. The ligand prospecting trials presented in this study showed that the enzymes were obtained in their functional form and that the menadione compound had the lowest interaction affinity among the evaluated compounds. In addition, low oxygen pressure enzymatic activity tests with the TcOYE protein proved to be effective for the determination of modulators of the functional activity of the protein. This work is a pioneer in the structural and functional characterization of LbOYE.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 16, 2010). Includes bibliographical references. Also issued in print.

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We developed a mixed model to determine whether biotic (alewife, spottail shiner, round goby, yellow perch > age 1 and yellow perch < age 1 abundances) or abiotic (water temperature, water clarity) factors influenced growth rates in the Indiana waters of Lake Michigan during August from 1984 to 2007. This study suggests that young-of-the-year (YOY) yellow perch growth rates in southern Lake Michigan are influenced by temperature, spottail shiner abundance, and round goby abundance. We also collected age-0 yellow perch to identify details of early life history including timing of migration to pelagic waters, timing of return to nearshore waters, and spatial distribution following return to nearshore waters. This study suggests that yellow perch larvae hatch and are in the nearshore waters from June 1 to June 24, return date for demersal YOY yellow perch ranges from July 8 to August 16, with a mean return date of July 25, and spatial distribution of demersal age-0 yellow perch is relatively homogenous in Indiana nearshore waters. / Department of Biology

Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1997. / Bibliography: leaves 118-132.

Thesis (Ph. D.)--University of Sydney, 2002. / Title from title screen (viewed Apr. 24, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Degree awarded 2002; thesis submitted 2001. Includes bibliography. Also available in print form.

Thesis (M.A.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 76-85). Also available via Humboldt Digital Scholar.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 127-136).

Thesis (Ph. D.)--University of Sydney, 2001. / Title from PDF title page (viewed on Aug. 10, 2005). Appendix 2 lacking in electronic version. Includes bibliographical references.