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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 lethal and non-lethal effects of ivermectin on cattle dung on the fly Neomyia cornicina

Gover, Jane Charlotte January 1995 (has links)
No description available.
2

Synthetic studies towards the avermectins and milbemycins

Willis, P. A. January 1988 (has links)
No description available.
3

Approaches to the synthesis of chrysothame and the avermectin southern hemisphere

Steel, K. I. M. January 1986 (has links)
No description available.
4

Synthesis and spectroscopic analysis of 4'-amino and 4'-sulfonamide chalcone derivatives and ultrastructural effects of 4'-sulfonamide boronic acid chalcone on Eimeria papillata sporozoites in vitro /

Matak, Andrija. January 2008 (has links)
Thesis (M.S.) - - Andrews University, College of Arts and Sciences, 2008. / Bibliography: leaves 159-168.
5

Iranian medicinal plants and antiparasitic compounds : from ethnobotany to contemporary scientific evidence /

Sairafianpour, Majid. January 2002 (has links)
Ph.d.
6

Synthetic and biological studies of antiparasitic natural product derivatives

Finokaliotou, Sophia January 2009 (has links)
Trypanosomiasis and Leishmaniasis are tropical diseases caused by the parasites Trypanosoma and Leishmania, that cause severe medical and economical problems for millions of people in the developing world. Trypanosomiasis can be divided into African and American trypanosomiasis, which are caused by Trypanosoma brucei and Trypanosoma cruzi respectively. There are more than 20 different species of Leishmania worldwide that cause Leishmaniasis, but the most severe infection, visceral leishmaniasis, is caused by Leishmania donovani. Both diseases are transmitted by blood sucking insects like the tsetse fly and the sand fly. The majority of existing drugs for trypanosomiasis and leishmaniasis are either too toxic or have low efficacy, and in some cases parasites have also developed resistance. There is therefore a pressing need to develop new chemotherapeutic agents, and in this context, the enzyme trypanothione reductase (TryR) has emerged as an attractive validated target for drug design. The natural product cadabicine, extracted from the plant Cadaba farinosa, is a diphenyl ether-containing macrocyclic spermidine alkaloid which has been identified as a potential inhibitor of TryR by virtual screening. In order to investigate the potential of cadabicine as a TryR inhibitor, an efficient synthetic route to the natural product was delivered. This work was focused on the preparation and combination of three key synthetic units, namely an orthogonally protected spermidine derivative and two functionalised cinnamic acid units. This approach lead to the formation of the macrocycle by an intramolecular nucleophilic aromatic substitution followed by a convenient conversion to the natural product. In the same manner cyclic and noncyclic analogues of cadabicine were prepared, in order to examine the structure-activity relationship of these alkaloids to TryR.
7

AÃÃo tripanocida de um mastoparano de Polybia paulista e seu possÃvel mecanismo de aÃÃo / Trypanocidal action: A mastoparan isolated from Polybia paulista and its possible mechanism action

Juliana Freire Chagas Vinhote 18 June 2015 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / A doenÃa de Chagas, considerada uma doenÃa negligenciada, à uma infecÃÃo parasitÃria causada pelo Trypanosoma cruzi e endÃmica em diversos paÃses. No Brasil, apenas o Benzonidazol à usado para o tratamento da doenÃa. Nesse contexto, o potencial terapÃutico das toxinas vem cada vez mais conquistando espaÃo e despertando grandes interesses da comunidade cientÃfica. Os venenos de invertebrados tÃm apresentado grande interesse como fonte de substÃncias bioativas. Os mastoparanos, a classe mais amplamente descrita de peptÃdeos isolados a partir da peÃonha de vespas, ja evidenciaram diferentes atividades biolÃgicas. Assim, os peptÃdeos isolados tÃm despertado interesse cientÃfico como fonte de modelos moleculares para o possÃvel desenvolvimento de novas terapias farmacolÃgicas. Este estudo investigou o efeito do peptideo mastoparano (MP) isolado do veneno da vespa Polybia paulista sobre cepa Y de Trypanosoma cruzi e seu possÃvel mecanismo de aÃÃo. Formas epimastigotas de T. cruzi foram cultivadas, tratadas com diferentes concentraÃÃes de MP e incubadas durante 24, 48 e 72 horas. Formas tripomastigotas de T. cruzi obtidas atravÃs de infecÃÃo de cÃlulas LLCMK2 foram subcultivadas, tratadas com diferentes concentraÃÃes de MP e incubadas durante 24 horas. Para investigar a participaÃÃo das espÃcies reativas de oxigÃnio (ERO) no efeito citotÃxico do mastoparano sobre formas epimastigotas de T.cruzi, placas foram incubadas com a CI50 de 24h de MP e a anÃlise da emissÃo de fluorescÃncia foi realizada em citometria de fluxo apÃs adiÃÃo de DCF. O efeito de mastoparano sobre o potencial de membrana mitocontrial das formas epimastigotas foi realizado pelo ensaio com rodamina 123. A citotoxicidade foi avaliada sobre celulas Raw 264.7 e a viabilidade dos macrÃfagos foi determinada utilizando o ensaio com MTT. No estudo de Docking molecular, obteve-se inicialmente a estrutura tridimensional do mastoparano a partir da sequÃncia primÃria em programa especÃfico. ApÃs anÃlise dos sÃtios de ligaÃÃo entre peptÃdeo e enzima TcGAPDH, a estrutura cristalogrÃfica do complexo TcGAPDH-chalepina foi utilizada para comparaÃÃo. O mastoparano inibiu o crescimento das formas epimastigotas de T. cruzi, apresentando uma CI50 de 102 Âg/mL, 53,95 Âg/mL e 58,51 Âg/mL para 24, 48 e 72 horas de incubaÃÃo respectivamente. Na anÃlise da produÃÃo de espÃcies reativas houve um aumento significativo na intensidade relativa de fluorescÃncia, quando comparado ao grupo controle. O peptideo alterou o potencial da membrana mitocondrial do parasita. Para as formas tripomastigotas a CI50 foi 8,83 Âg/mL apÃs 24h de incubaÃÃo. A citotoxidade do mastoparano avaliada em macrÃfagos nÃo induziu morte celular significativa nas diferentes concentraÃÃes estudadas. No estudo de docking, foi evidenciado o acoplamento do mastoparano na TcGAPDH, demonstrando os diferentes sÃtios de ligaÃÃo dos resÃduos de aminoÃcidos do centro ativo da enzima e comparando a semelhanÃa na posiÃÃo ocupada pela molÃcula chalepina na TcGAPDH. Conclui-se que o mastoparano apresentou atividade tripanocida envolvendo a participaÃÃo do estresse oxidativo e alteraÃÃo do potencial de membrana sem apresentar citotÃxica em cÃlulas de macrÃfagos e parece inibir a TcGAPDH de T. cruzi. Portanto, o mastoparano se destaca como importante molÃcula bioativa contra os parasitas.
8

Tricyclic purine analogues as antiparasitic and antiviral agents

Hagos, Asmerom M., January 2003 (has links) (PDF)
Thesis (Ph. D.)--School of Chemistry and Biochemistry, Georgia Institute of Technology, 2004. Directed by Katherine L. Seley. / Includes bibliographical references (leaves 113-126).
9

Target elucidation of novel trypanosomatid inhibitors

Fraser, Andrew Logan January 2018 (has links)
In 2010 the Florence group completed the total synthesis of the natural product chamuvarinin which, in collaboration with the Smith group, was found to be a potent inhibitor of the pathogenic parasite T. brucei. Several simplified analogues were found to maintain this inhibitory activity alongside activity against the related species T. cruzi and L. major. The mechanism of action and structural features of these compounds responsible for the observed biological activity remained elusive despite a large synthetic effort by the Florence group. With the aim of identifying protein targets in trypanosomatids to understand the mechanism of action, several photo-affinity labeling analogs have been successfully synthesised and utilised to identify a primary protein target. This protein target was fully validated and molecule docking to this protein was evaluated in-silico. This computational data was used to evaluate the mode of action and aided in the design of simplified compounds which were found to maintain the previously observed anti-parasitic activity but with decreased toxicity to mammalian cells alongside decreased synthetic complexity. The total synthesis of the natural product ascr#18 is also described alongside the synthesis of photo-affinity labeling analogs. This natural product is implicated in the modulation of pathogen resistance in plants and has potential application in crop production.
10

Síntese, comprovação estrutural e atividade antitumoral e antiparasitária de novos derivados benzodioxolicos / Síntese , caracterização estrutural e avaliação da atividade antitumoral e antiparasitária de novos derivados benzodioxolicos

SILVA, Willams Leal 04 August 2016 (has links)
Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-04-25T13:06:43Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE CATALOGADA 19.pdf: 3608512 bytes, checksum: 1c5363a2c904d02f78a6ed3352207710 (MD5) / Made available in DSpace on 2017-04-25T13:06:43Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE CATALOGADA 19.pdf: 3608512 bytes, checksum: 1c5363a2c904d02f78a6ed3352207710 (MD5) Previous issue date: 2016-08-04 / FACEPE / O câncer destaca-se como um importante problema de saúde pública, além de configurar uma das principais causas de morte no mundo. Considerando que em 2012 houve cerca de 8,2 milhões de mortes. Este trabalho teve como objetivo a obtenção de novos derivados benzo1,3-dioxol (NW), por estratégia de hibridação molecular a fim de reunir características estruturais em uma única estrutura com propriedades farmacológicas mista, dual ou dupla. A síntese consiste na reação em duas rotas paralelas partindo dos aldeídos benzo[d][1,3]dioxol4-carbaldeído e benzo[d][1,3]dioxol-5-carbaldeído, seguida de reações de condensação com tiossemicarbazidas para obtenção de tiossemicarbazonas que podem ser conduzidas a uma ciclização com ácido monocloroácetico formando o anel 4-tiazolidina. Todos os compostos tiveram suas estruturas comprovadas por RMN1H, RMN 13C, COSY, IV e pirólise acoplado a espectrometria de massas. Os compostos benzodioxois (NW) obtidos foram testados a fim de avaliar a atividade antiproliferativa in vitro utilizando-se o ensaio da sulforrodamina B (SBR) para avaliação do crescimento celular frente várias linhagens tumorais. Para o teste antitumoral realizado os resultados obtidos mostram um derivado promissor NW-03 com GI50 estabelecidas entre 2,9 a 14,4 μM, quando comparado ao controle positivo utilizado. Diante dos resultados obtidos os derivados foram classificados como ativos e mostraram um perfil citostático. Além disso, os resultados obtidos corroboram para uma associação de núcleos viáveis por meio da hibridação molecular entre o benzo-1,3-benzodioxol e tiossemicarbazona levando a resultados promissores. Posteriormente os compostos foram submetidos a ensaios de citoxicidade e avaliação antiparasitária onde foi possível eleger os compostos promissores NW-03, NW-06 e NW-11 com baixa toxicidade para esplenócitos e atividade antiparasitária. Em relação à atividade tripanocida, o composto NW-13 (1-naftil) exibiu elevados níveis de atividade contra epimastigota e tripomastigota (IC50 = 1,48 e 3,89 µM, respectivamente). Com o estudo de docking foi possível estabelecer correlação do encaixe de compostos NW-02 E NW-09 com o alvo cruzaína através de interações. O composto NW-03 foi avaliado como possível inibidor de tirosinase através de experimento de titulação por técnica de espectroscopia de ressonância magnética nuclear e espectrofotometria. / The cancer stands out as a major public health problem, and configure one of the leading causes of death worldwide. Whereas in 2012 there were about 8.2 million deaths. This study aimed to obtain new derivatives benzo-1,3-dioxole (NW), by molecular hybridization strategy to gather structural features in a single structure with mixed pharmacological properties, dual or double. The synthesis consists of two parallel routes reaction starting from the aldehydes benzo [d] [1,3] dioxol-4-carbaldehyde and benzo [d] [1,3] dioxol-5-carbaldehyde, followed by condensation reactions to tiossemicarbazidas obtaining thiosemicarbazone that can be conducted with a cyclized with monochloroacetic acid to form the 4-thiazolidine ring. All compounds had their structures evidenced by 1 H NMR, 13C NMR, COSY, IV and coupled pyrolysis mass spectrometry. Benzodioxoles The compounds (NW) have been tested in order to assess the antiproliferative activity in vitro using the sulforhodamine B assay (SBR) for evaluation of cell growth across various tumor cell lines. For antitumor test performed the results obtained show a promising derived NW-03 GI50 established between 2.9 to 14.4 uM when compared to the positive control used. Results obtained derivatives were classified as active and showed a cytostatic profile. Moreover, the results support an association of viable nuclei by means of molecular hybridization between the benzo-1,3-benzodioxole thiosemicarbazone leading to promising results. Later the compounds were subjected to cytotoxicity testing and antiparasitic assessment where it was possible to elect the promising compounds NW-03, NW 06 and NW-11 with low toxicity to splenocytes and antiparasitic activity. Regarding trypanocidal activity, NW-13 compound (1-naphthyl) exhibited high levels of activity against epimastigote and trypomastigote (IC50 = 1.48 and 3.89 uM, respectively). With the docking study was possible to establish compounds fitting correlation NW-02 and NW-09 with the target cruzain through interactions. NW-03 The compound was evaluated as a possible inhibitor of tyrosinase by titration experiment for technical nuclear magnetic resonance spectroscopy, and spectrophotometry.

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