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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

Estudos sobre a filogenia, taxonomia e evolução de caracteres reprodutivos em Moraceae Gaudich / Studies on phylogeny, taxonomy and evolution of reproductive characters in Moraceae Gaudch

Ribeiro, Jose Eduardo Lahoz da Silva 18 December 2007 (has links)
Orientador: George John Shepherd / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T11:39:18Z (GMT). No. of bitstreams: 1 Ribeiro_JoseEduardoLahozdaSilva_D.pdf: 15364889 bytes, checksum: aff367f6d443eb922d7c26df60d67b5c (MD5) Previous issue date: 2007 / Resumo: A família Moraceae é extremamente bem representada em número de indivíduos e espécies em florestas neotropicais de baixa altitude. Entretanto, a maior parte das informações disponíveis sobre o grupo, até o presente, refere-se apenas as espécies de Ficus. São raros os trabalhos sobre a evolução dos caracteres presentes nas diferentes inflorescências que ocorrem na família, que, em alguns casos, estão entre as mais complexas dentro das Angiospermae, e as informações sobre o relacionamento filogenético infrafamiliar, assim como as delimitações de suas tribos, precisam ser enriquecidas com mais dados para serem melhor compreendidas. Neste contexto, foi desenvolvido o presente trabalho, que teve como objetivos o estudo da filogenia de Moraceae, especialmente, as neotropicais, a partir de dados moleculares do segmento trnL-F do cloroplasto e de 50 caracteres morfológicos; o levantamento e análise da evolução de caracteres relacionados às inflorescências do grupo, e a caracterização morfológica das tribos da família. Além da árvore filogenética gerada a partir das análises realizadas para desenvolvimento do presente trabalho, cladogramas disponíveis na literatura, gerados a partir de informações moleculares de outros segmentos gênicos, também foram utilizados para avaliação da delimitação das tribos de Moraceae e estudo da evolução dos caracteres analisados. Os resultados das análises realizadas permitiram a proposição de uma nova tribo, Maclureae; uma nova delimitação para as tribos Dorstenieae e Moreae, correntemente aceitas; a elaboração de uma chave de identificação; a caracterização morfológica de todas as tribos apresentadas, e inferências sobre a evolução de alguns caracteres reprodutivos. Além disso, o sistema reprodutivo das 278 espécies neotropicais foi inferido a partir da observação em campo de 40 espécies, entre essas 28 espécies arbóreas, indicando que monoicia é o sistema reprodutivos mais comum no grupo, seguido de dioicia e androdioicia. As inflorescências de Antiarideae (Castilleae) bem como estruturas associadas a elas receberam novas interpretações após estudos morfológicos / Abstract: The Moraceae family is extremely well represented in individual and species number, in lowland neotropical forests. However, the most expressive part of the available information about this group, up to now, refers to Ficus species. There are few studies focusing on character evolution of the different types of inflorescences in this family, which are, in some cases, among the most complexes in the Angiospermae; and information on within-family phylogenetic relationship, as well as its tribes¿s delimitation, must be enhanced with more data, in order to be better understood. The present work was developed bearing in mind this context and aiming i) the study of the Moraceae phylogeny, especially the neotropical species, using molecular data from the chloroplast trnL-F region and from 50 morphological data; ii) the cataloging and evolutionary analysis of characters related to inflorescences of this group, and iii) the morphological characterization of the tribes. In addition to the phylogenetic tree generated from analysis carried out for the development of the present work; cladograms available in the literature, based on information of different DNA segments, were also used to evaluate the delimitation of Moraceae tribes and to study the evolution of the analyzed characters. The results of the performed analysis allowed the proposition of a new tribe, Maclureae; a new delimitation of Dorstenieae and Moreae, currently accepted; the elaboration of an identification key; the morphological characterization of all depicted tribes, and inferences about the evolution of some reproductive characters. Additionally, the reproductive system of the 278 neotropical species was inferred from field observation of 40 species, 28 of which were tree species, indicating that monoecy is the most common reproductive system in the group, followed by dioecy and androdioecy. After morphological studies, Antirideae (Castilleae) inflorescences, as well as related structures, have received new interpretation / Doutorado / Doutor em Biologia Vegetal
2

Bacterial Biofilm Inhibition and Antifungal Activity of Neotropical Plants

Ta, Chieu Anh Kim January 2015 (has links)
This thesis examined the antimicrobial activity of select neotropical plants from Costa Rica and traditional Q’eqchi Maya medicines from Belize. In particular the potential for interference with bacterial quorum sensing (QS) and biofilm formation as well as fungal growth were assessed. Of one hundred and twenty six extracts collected from Costa Rica, one third showed significant QS inhibition while 13 species displayed more biofilm inhibitory activities than the positive control allicin. The active species belonged to the Lepidobotryaceae, Melastomataceae, Meliaceae, Sapindaceae, and Simaroubaceae. Twelve Marcgraviaceae species were tested for the same biological activities; of these, three showed similar QS inhibition to that of the positive control Delisea pulchra (Greville) Montagne and five with at least 30% biofilm inhibition. Only one species inhibited fungal growth – Marcgravia nervosa Triana & Planch. Bioassay-guided isolation of this plant resulted in the identification of the active principle as a naphthoquinone, with a minimum inhibitory concentration (MIC) ranging from 85 to 100 μM against Saccharomyces cerevisiae. Similarly, sixty one Q’eqchi’ Maya medicinal plant species were evaluated for their antimicrobial activities. Of these, four species showed more QS inhibition than D. pulchra, seven with comparable biofilm inhibitory activities that of allicin, and two with similarly antifungal activity to berberine. Two spirostanol saponins were isolated from Cestrum schlechtendahlii G.Don, an active antifungal plant. The major saponin showed growth inhibition against Saccharomyces cerevisiae and Fusarium graminearum, with MICs of 16.5 μM and 132 μM, respectively. Further analyses of this compound using chemical genomics suggested that its antifungal mechanism of action is pleiotropic, affecting multiple targets. Taken together, these findings showed that neotropical plants and traditional Q’eqchi’ Maya medicines contain phytochemicals that interfere with bacterial biofilm formation and quorum sensing as well as fungal growth.

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