Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 83-87). Also available via the Internet.

No description available.

Made available in DSpace on 2014-06-12T18:07:20Z (GMT). No. of bitstreams: 2 arquivo6437_1.pdf: 333606 bytes, checksum: e93c5a225d5876158ca1324ee0a7204e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2002 / Investigações feitas com organismos que apresentam o fenótipo de resistência a compostos tóxicos são importantes nas áreas biotecnológica, clínica e agrícola. Neste trabalho, foi observada a correlação entre os níveis de resistência de células de levedura ao fungicida agrícola Benomyl􀂣 e a presença de determinados genes envolvidos com o processo. Uma linhagem selvagem da K. marxianus e várias linhagens industriais de S. cerevisiae foram testadas para a variação inter e intraespecífica desta resistência. A metodologia usada abordou os genes TUB2 e ICT1. O gene TUB2 codifica a proteína 􀁅-tubulina que está relacionada com a formação do citoesqueleto. Variações alélicas desta proteína estão relacionadas com a sensibilidade ao fungicida Benomyl®. O gene ICT1 é componente do sistema MDR (Multidrug Resistence) de leveduras. Sua função é desconhecida, embora sua inativação parece promover sensibilidade as drogas. As análises da cinética do crescimento celular das linhagens testadas na presença de Benomyl®, juntamente com o perfil de amplificação gênica destes dois genes, sugerem um complexo mecanismo de defesa celular

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 89-100). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 89-100). Also available on the Internet.

No description available.

The synthesis of poly (butyl vinyl ether) and poly (butyl vinyl ether 2-chloroethyl vinyl ether) random copolymers was accomplished through the use of the aluminum hydrogen sulfate catalyst (AHS). In this system, AHS acts as a heterogeneous catalyst in the cationic polymerization of vinyl alkyl ethers. Highly isotactic polymers (greater than 70%) have been prepared and characterized by IH and 13C NMR. DSC characterization of poly(butyl vinyl ether) also reveals that these polymers are semicrystalline. Gel permeation chromatography characterization and intrinsic viscosity data of poly(butyl vinyl ether), and poly{butyl vinyl ether-2-chloroethyl vinyl ether) homopolymers and copolymers indicate fairly narrow polydispersities, and very high molecular weights. A study of this copolymerization by lH NMR revealed that the 2-chloroethyl ether monomer was being incorporated along the chain with the greater percentage of the 2-chloroethyl vinyl ether monomer near the chain ends. Reactions on the pendent chlorine group are currently under investigation in our laboratories. It is anticipated that a range of pendent functional groups can be obtained. / Master of Science

Parkinson's disease (PD) is a slow-progressive neurodegenerative disorder affecting 5-6 million people around the globe. The disease is manifested by the rapid deterioration of dopaminergic cells in the substantia nigra portion of the brain; however, the pathological mechanism of selective dopaminergic neuronal death is unknown. A reduction in levels of 3,4-dihydroxyphenylacetaldehyde (DOPAL) is biologically critical as this aldehyde has been shown to be toxic to dopaminergic cells and is a highly reactive electrophile. Investigating neuronal protein targets is essential in determining the cause of toxicity. An essential protein-GAPDH (e.g., glyceraldehyde-3-phosphate dehydrogenase) is an abundantly expressed enzyme known for its glycolytic activity, and recent research has implicated its role in oxidative stress-mediated neuronal death. This work positively shows GAPDH as a target for DOPAL modification, and, for the first time, DOPAL is identified as a potent inhibitor for GAPDH enzymatic activity. LC-MS and other chemical probes (ie. thiol and amine modifiers) show that DOPAL modifies specific –Lys, -Arg, and –Cys residues in the cofactor binding-domain of GAPDH. The enzyme inhibition is also time and DOPAL dose-dependent. DOPAL has a unique structure, containing two reactive functional groups: an aldehyde and catechol ring. In-house syntheses of DOPAL analogues, containing the catechol group and lacking the aldehyde, and vice versa have been tested on GAPDH and do not inhibit or modify GAPDH. Therefore, both the catechol and aldehyde groups of DOPAL are specific to binding with GAPDH and are necessary to achieve modification and enzyme inhibition. In addition to finding a novel enzyme inhibited and modified by DOPAL, this work has also confirmed linking DOPAL levels to a fungicide associated with PD risk. This benzimidazole fungicide, benomyl was shown to inhibit ALDH2 in the SH-SY5Y neuroblastoma cell line via an increase in DOPAL and a decrease in DOPAC. The ratios of DOPAL and DOPAC, the product of ALDH, were measured by HPLC-ECD, and found that benomyl does inhibit ALDH2 in this dopaminergic cell model. The cytotoxicity of benomyl, DA, DOPAL and the combination of DA or DOPAL with benomyl was assessed by MTT assay. Surprisingly, the only toxic combination was the combination of DA or DOPAL with benomyl. In fact, this toxicity appears to be synergistic, as none of the single treatments are significantly toxic to the cells. This synergistic effect also affects GAPDH aggregation. The cell morphology is also drastically different in the presence of the combined treatments, compared to individual treatment of DA, DOPAL or benomyl; cells start to ebb and show apoptotic-like features at just 2h. A second class of pesticides, named chlorpyrifos and chlorpyrifos-oxon were tested for toxicity in PC6-3These compounds were toxic to these cells due to DOPAL accumulation reaching high levels in the 100 µM range. Exposure to environmental toxins such as pesticides and fungicides has long been linked to PD risk, but only recently to DOPAL levels. This work provides a novel mechanism by which fungicide exposure may stimulate PD pathogenesis.

Orientador: Luiz Antônio Graciolli / Banca: Luzia Doretto Paccola Meirelles / Banca: Marli de Fátima Stradioto Papa / Abstract: The occurrence of contaminants fungus and competitors are common during the shiitake cultivation in logs. In Brazil, few are the works that identify and they analyze the effects of these microorganisms in the shiitake production. However, it is known that the incidence of these fungus in great proportions can take to the unproductiveness the logs. Therefore, the present work had as objective to test the effect of the moisturized whitewash and of the fungicide benomyl in the control of contaminant fungus and his answer in the shiitake production in logs. For so much, it was tested in vitro previously the effect of the benomyl in different concentrations (0.5; 1.0; 2.0; 4.0; 8.0 and 16.0 mg/mL) in the mycelial growth of five shiitake lineages (JAB-L; JAB-K; LE-96/17; LE-95/01 and, LE-96/22), in way to select the most tolerant lineage to the concentrations of proposed benomyl, comparing with the growth of the same ones without the presence of this fungicide (control). A completely randomized design in a factorial scheme 5X7, tends in the total 35 treatments, each one with three repetitions, corresponding to a plate of Petri. It was observed that only shiitake lineage did not suffer any effect of the benomyl in the proposed concentrations was the LE-96/17, being the chosen to be used in the experiment in logs, when the largest benomyl concentration was submitted (16.0 mg/mL). The other study was conducted in logs in an interely randomized design, with three treatments: control; whitewash (8 kg of whitewash / 60 liters of water) applied in the production logs soon after the inoculation and after each induction shock; and benomyl (16.0 mg/mL) applied biweekly starting from the inoculation of the logs. Each treatment contained 60 repetitions, being the experimental unit corresponding to a log. The used logs were of Eucalyptus urophylla, which were... (Complete abstract, click electronic address below). / Resumo: A ocorrência de fungos contaminantes e competidores é comum durante o cultivo de shiitake em toros. No Brasil, poucos são os trabalhos que identificam e analisam os efeitos destes microrganismos na produção de shiitake. No entanto, sabe-se que a incidência destes fungos em grandes proporções pode levar à improdutividade dos toros. Portanto, o presente trabalho teve como objetivo testar o efeito da cal hidratada e do fungicida benomyl no controle de fungos contaminantes e sua resposta na produção de shiitake em toros. Para tanto, testou-se anteriormente in vitro o efeito do benomyl nas concentrações 0,5; 1,0; 2,0; 4,0; 8,0 e 16,0 mg/mL no crescimento micelial das linhagens de shiitake JAB-L; JAB-K; LE-96/17; LE-95/01 e LE-96/22, de modo a selecionar a linhagem mais tolerante as concentrações de benomyl propostas, comparando com o crescimento das mesmas sem a presença deste fungicida (testemunha). O delineamento deste experimento foi inteiramente casualizado em fatorial 5X7, tendo no total trinta e cinco tratamentos, cada qual com três repetições, sendo cada repetição correspondente a uma placa de Petri. Observou-se que a única linhagem de shiitake a não sofrer qualquer efeito do benomyl nas concentrações propostas foi a LE-96/17, sendo a escolhida para ser utilizada no experimento em toros, a qual foi submetida a maior concentração de benomyl (16,0 mg/mL). O delineamento do experimento em toros foi inteiramente casualizado, com três tratamentos: testemunha; cal (8 kg de cal/ 60 litros de água) aplicados nos toros de produção logo após a inoculação e após cada choque de indução; e benomyl (16,0 mg/mL) aplicados quinzenalmente a partir da inoculação dos toros. Cada tratamento conteve 60 repetições, sendo a unidade experimental correspondente a um toro. Os toros utilizados foram de Eucalyptus urophylla, os quais foram inoculados... (Resumo completo, clicar acesso eletrônico abaixo). / Mestre

Made available in DSpace on 2014-06-11T19:29:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-05-15Bitstream added on 2014-06-13T21:00:07Z : No. of bitstreams: 1 andrade_mcn_me_ilha.pdf: 261991 bytes, checksum: 006fec132b03beb5f46f5030a336fa9b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A ocorrência de fungos contaminantes e competidores é comum durante o cultivo de shiitake em toros. No Brasil, poucos são os trabalhos que identificam e analisam os efeitos destes microrganismos na produção de shiitake. No entanto, sabe-se que a incidência destes fungos em grandes proporções pode levar à improdutividade dos toros. Portanto, o presente trabalho teve como objetivo testar o efeito da cal hidratada e do fungicida benomyl no controle de fungos contaminantes e sua resposta na produção de shiitake em toros. Para tanto, testou-se anteriormente in vitro o efeito do benomyl nas concentrações 0,5; 1,0; 2,0; 4,0; 8,0 e 16,0 mg/mL no crescimento micelial das linhagens de shiitake JAB-L; JAB-K; LE-96/17; LE-95/01 e LE-96/22, de modo a selecionar a linhagem mais tolerante as concentrações de benomyl propostas, comparando com o crescimento das mesmas sem a presença deste fungicida (testemunha). O delineamento deste experimento foi inteiramente casualizado em fatorial 5X7, tendo no total trinta e cinco tratamentos, cada qual com três repetições, sendo cada repetição correspondente a uma placa de Petri. Observou-se que a única linhagem de shiitake a não sofrer qualquer efeito do benomyl nas concentrações propostas foi a LE-96/17, sendo a escolhida para ser utilizada no experimento em toros, a qual foi submetida a maior concentração de benomyl (16,0 mg/mL). O delineamento do experimento em toros foi inteiramente casualizado, com três tratamentos: testemunha; cal (8 kg de cal/ 60 litros de água) aplicados nos toros de produção logo após a inoculação e após cada choque de indução; e benomyl (16,0 mg/mL) aplicados quinzenalmente a partir da inoculação dos toros. Cada tratamento conteve 60 repetições, sendo a unidade experimental correspondente a um toro. Os toros utilizados foram de Eucalyptus urophylla, os quais foram inoculados... .