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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

Phylogeny of Phlegmariurus (Lycopodiaceae) focusing on Brazilian endemic species / Filogenia de Phlegmariurus (Lycopodiaceae) com ênfase em espécies endêmicas do Brasil

Gissi, Danilo Soares 20 March 2017 (has links)
Phlegmariurus is the most abundant genus of Lycopodiaceae in Brazil with 40 species, 24 of which are endemic, occurring mainly in the Atlantic Rainforest and Rocky Fields (“Campos Rupestres”) in the Espinhaço range. Some phylogeny works with the group had already been carried out, but not including a representative sample of the Brazilian species. Thus, we performed a molecular phylogeny of Phlegmariurus species endemic in Brazil using three molecular markers of cpDNA. Phlegmariurus showed to be monophyletic, including two clades, one Neotropical and another Paleotropical. All the Brazilian species sampled appeared in the Neotropical clade. The endemic species appeared in several clades alongside Andean species. Epiphytism and the microphylls differentiation were optimized at the obtained clade and they appeared several times in the evolutionary history of the group / Phlegmariurus é o gênero mais abundante de Lycopodiaceae no Brasil com 40 espécies, sendo 24 destas endêmicas, ocorrendo principalmente na Mata Atlântica e Campos Rupestres da Cadeia do Espinhaço. Alguns trabalhos de filogenia com o grupo já haviam sido realizados, contudo sem incluir uma amostragem representativa das espécies brasileiras. Dessa forma, realizamos a filogenia molecular das espécies de Phlegmariurus endêmicas do Brasil utilizando três marcadores moleculares de cpDNA. Phlegmariurus se mostrou monofilético, incluindo dois clados, um Neotropical e outro Paleotropical. Todas as espécies brasileiras amostradas apareceram no clado neotropical. As espécies endêmicas apareceram em vários clados em meio as espécies andinas. O epifitismo e a diferenciação dos microfilos foram otimizados nos clados obtidos e indicaram que essas características surgiram várias vezes na história evolutiva do grupo
2

Phylogeny of Phlegmariurus (Lycopodiaceae) focusing on Brazilian endemic species / Filogenia de Phlegmariurus (Lycopodiaceae) com ênfase em espécies endêmicas do Brasil

Danilo Soares Gissi 20 March 2017 (has links)
Phlegmariurus is the most abundant genus of Lycopodiaceae in Brazil with 40 species, 24 of which are endemic, occurring mainly in the Atlantic Rainforest and Rocky Fields (“Campos Rupestres”) in the Espinhaço range. Some phylogeny works with the group had already been carried out, but not including a representative sample of the Brazilian species. Thus, we performed a molecular phylogeny of Phlegmariurus species endemic in Brazil using three molecular markers of cpDNA. Phlegmariurus showed to be monophyletic, including two clades, one Neotropical and another Paleotropical. All the Brazilian species sampled appeared in the Neotropical clade. The endemic species appeared in several clades alongside Andean species. Epiphytism and the microphylls differentiation were optimized at the obtained clade and they appeared several times in the evolutionary history of the group / Phlegmariurus é o gênero mais abundante de Lycopodiaceae no Brasil com 40 espécies, sendo 24 destas endêmicas, ocorrendo principalmente na Mata Atlântica e Campos Rupestres da Cadeia do Espinhaço. Alguns trabalhos de filogenia com o grupo já haviam sido realizados, contudo sem incluir uma amostragem representativa das espécies brasileiras. Dessa forma, realizamos a filogenia molecular das espécies de Phlegmariurus endêmicas do Brasil utilizando três marcadores moleculares de cpDNA. Phlegmariurus se mostrou monofilético, incluindo dois clados, um Neotropical e outro Paleotropical. Todas as espécies brasileiras amostradas apareceram no clado neotropical. As espécies endêmicas apareceram em vários clados em meio as espécies andinas. O epifitismo e a diferenciação dos microfilos foram otimizados nos clados obtidos e indicaram que essas características surgiram várias vezes na história evolutiva do grupo
3

A convergent synthesis of the skeleton of huperzine A and analogues

Foricher, Yann January 2000 (has links)
No description available.
4

Australasian Huperzia as potential sources of Huperzine alkaloids

Lim, Wei-Han January 2010 (has links)
The Lycopodiaceae is an ancient and cosmopolitan family of fern allies that include an estimated 35 Huperzia species occurring throughout the South-East Asian and Australian region. Thirteen species naturally occur in Australia and are found mainly in the tropical rainforests of far north Queensland. Over the past decade, there has been renewed interest in Huperzia and their respective Huperzine alkaloid concentrations following the discovery of Huperzine A (HupA) and Huperzine B (HupB) alkaloids in H. serrata (Thunb. ex Murray) Trevis. Both alkaloids are of pharmaceutical interest since they are highly selective and potent reversible inhibitors of acetylcholine esterase. Huperzine alkaloid concentrations of Australasian Huperzia have not been well documented, and no prior studies have been undertaken to investigate the amenability of Australasian Huperzia to alternative propagation techniques such as axenic culture. / This research presents an extensive screen of 16 Australasian Huperzia species to investigate their Huperzine alkaloid concentrations. HupA (0.032 to 1.012 mg g-1 DW) was detected in ten out of the sixteen Huperzia species examined, while HupB (0.008 to 0.339 mg g-1 DW) was detected in eight. From this extensive study, H. elmeri (Herter) Holub was observed as the species with the greatest potential to yield high Huperzine-containing individuals. In addition, the screen established that Australasian Huperzia generally contain higher HupA levels than H. serrata, the main source of commercial HupA, which on average only contains 0.082 mg g-1 DW HupA. The fractionation and spectrometric analysis of alkaloids as part of the screen led to the discovery of three Huperzine alkaloids co-occurring within the same plant: HupA, HupB and Huperzine C, isolated from an individual of an Australian H. carinata (Desv. Ex Poir.) Trevis. / The potential of establishing axenic cultures of Australasian Huperzia was also investigated in this research. Actively growing axenic cultures of H. carinata, H. squarrosa (C.Forster) Trevisan, H. phlegmaria (L.) Rothm. and H. phlegmarioidies (Gaudich.) Rothm., together with callus and cell suspension cultures of H. carinata and H. phlegmaria, were successfully established. The results suggest that culturing in total darkness is essential to allow for optimal callus and cell suspension growth. In addition, this study also investigated the possibilities of germinating various Huperzia spores, by both symbiotic and asymbiotic means. Germination of H. squarrosa spores was achieved by both symbiotic and asymbiotic means, and was only observed in cultures which were kept in the dark, implying that there is a form of photo-inhibition mechanism preventing spores from germinating when they are exposed to light. Beneficial effects of various types of spore treatments prior to sowing, in terms of increased spore germination was also observed. / In conclusion, the results presented suggest that Australasian Huperzia are indeed a potentially valuable resource for Huperzine alkaloids. The investigations into the conditions required for the successful introduction and maintenance of Australasian Huperzia in axenic culture has also further extended our understanding of these plants, and their amenability towards axenic culture conditions as a means of alternative propagation.
5

Stanovištní nároky a prediktivní modelování výskytu druhu Huperzia selago / Habitat requirements and predictive distribution modelling of Huperzia selago

Trachtová, Pavla January 2014 (has links)
Studies of the occurrence of montane and boreomontane species in ravines of the sandstone landscape are scarce and the occurrence of these species are explained by the presence of temperature inversion. The question is, which factors limit the occurrence ofthese species in ravines with temperature inversion. The aim of this diploma thesis is to reveal factors that influence the occurrence of Huperzia selago in inverse ravines of sandstone landscape. This work uses a habitat variables recorded directly for populations of H. selago and variables derived from a digital elevation model. These derived variables are also used for creation of two predictive models of geographic distribution of H. selago in the National Park Bohemian Switzerland. When we summarize the most informative variables of predictive models and habitat conditions significantly different from control sites, we get the typical habitat of H. selago. Such sites will likely be found on the rock at the bottom of the valley. Factors that influence the suitability of habitat are: moisture, vegetation type, slope, and distance to the bottom of the valley.

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