Thesis (Ph.D.)--University of Tasmania, 1994. / Thesis (Ph.D.)--University of Tasmania, 1994. Includes bibliographical references (leaves 434-474). Includes bibliographical references (leaves 434-474).

Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 187-194).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 157-167.

Thesis--Massachusetts Institute of Technology/Woods Hole Oceanographic Institution. / "WHOI-80-21." Vita. Includes bibliographical references (p. 187-206).

Orientador: Lin Chau Ming / Banca: Alexandra Christine Helena F. Sawaya / Banca: Marcos Roberto Furlan / Resumo: A espécie Mikania laevigata Sch. Bip. ex Baker, popularmente conhecida como guaco, pertence à família Asteraceae, é originária da região sul do Brasil e está entre as plantas medicinais adotadas pelo Sistema Único de Saúde do Brasil. M. laevigata é uma opção agrícola promissora no cultivo das medicinais, estando acessível ao pequeno produtor, tendo em vista a crescente demanda do mercado consumidor brasileiro por fitoterápicos. Uma vez que as plantas medicinais são classificadas como produtos naturais, a lei permite que sejam cultivadas e comercializadas desde que se atinja o padrão de qualidade necessário. O presente trabalho foi instalado e conduzido na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas - UNESP, Campus de Botucatu, Estado de São Paulo. O objetivo desta pesquisa foi avaliar a produtividade de biomassa e teor de cumarina do guaco colhido em diferentes idades da planta. Foi observada maior produtividade para as variáveis avaliadas aos onze meses de idade do guaco, obtendo 0,96 t ha-1 de matéria seca de folha sendo que não houve diferença estatística quanto ao teor de cumarina aos 7, 9, e 11 meses de idade de Mikania laevigata. Nas condições em que foi realizada a pesquisa, o maior rendimento de biomassa x teor de cumarina foi obtido aos 11 meses de idade do guaco, o qual possibilitou o melhor resultado para o rendimento extrativo de cumarina em folhas secas. / Abstract: The species Mikania laevigata Sch. Bip. ex Baker, popularly known as guaco, belongs to the Asteraceae family and it is native to southern Brazil it is among the medicinal plants adopted by the Unified Health System in Brazil (SUS). M. laevigata is a promising option in agricultural cultivation of medicinal plants and is accessible to small farmers, in view of the growing demand of the Brazilian market for herbal medicines. Since medicinal plants are classified as natural products, the law allows them to be grown and marketed it they achieve the required quality standards. This work was conducted at the Lageado Experimental Farm, Faculty of Agricultural Sciences - UNESP, Botucatu, State of São Paulo. The objective of this research was to evaluate the productivity of biomass and coumarin content of guaco harvested at different ages of the plant. It was observed higher productivity for the variables evaluated at eleven months of guaco, obtaining 0.96 t ha-1 of dry leaf and there was no statistical difference in the coumarin content at 7, 9, and 11 months of age Mikania laevigata. The conditions under which the survey was conducted, the higher biomass yield x coumarin content of guaco was obtained at 11 months of age, which enabled the best result for the extraction yield of coumarin in dry leaves / Mestre

M.Sc. (Chemistry) / The extraction of the atropine and scopolamine alkaloids from both Datura ferox and Datura stramonium was carried out in this study to investigate potential of these plants as a source of these alkaloids. Tropane alkaloids such as atropine occur naturally in many members of several plant families, especially the Solanaceae, Erythroxylaceae, Proteaceae and Convolvulaceae families. Hyoscyamine or its racemic mixture atropine is used as an antidote to organophosphate insecticides, or as a nerve agent to dilate the pupil for retina examinations. Scopolamine or hyoscine is used to treat motion sickness, among other uses. Tropane alkaloids are often difficult to synthesise, and their extraction from commercial sources is therefore of some commercial interest. A systematic study was carried by comparing different extraction methods for the efficiencies of tropane alkaloid (TA) extraction at ambient pressure. The two plants selected are already widely spread as weeds in many regions in South Africa and are therefore well adapted to the local conditions. Among the extraction methods, TA’s were extracted in their acidic form using dilute aqueous acids with 5% sulfuric acid giving the highest yield of both atropine and scopolamine. Alternatively, the TA’s were extracted in their basic form from the plant material using basified organic solvents. The overall yields obtained were not significantly different from those obtained by using dilute aqueous acids, with D. ferox giving approximately 0.24 % and 0.0028 % scopolamine and atropine, respectively. D. stramonium on the other hand gave approximately 0.037 % and 0.002% atropine and scopolamine, respectively. Different plant parts were also tested in order to determine if there was an advantage in extracting the tropane alkaloids at a particular time in the growth, but concluded that the best option was to extract the seeds for various reasons such as the presence of relatively less chlorophyll...

Magister Scientiae - MSc / Since Helichrysum is known by the indigenous people of Africa for therapeutic properties, such as against colds, flu and wounds, the aim of this study was to focus on the patulum species found predominantly in the Western Cape region of South Africa and by means of isolation and identification of the plant constituents, be able to relate the therapeutic activity on the basis of literature precedents, to the compounds extracted. / South Africa

M.Sc. (Botany) / Please refer to full text to view abstract

No description available.

Cellulose and hemicellulose account for a large portion of the world‘s plant biomass. In nature, these polysaccharides are intertwined forming complex materials that require multiple enzymes to degrade them. Multi-enzyme complexes (MECs) consist of a number of enzymes working in close proximity and synergistically to degrade complex substrates with higher efficiency than individual enzymes. The cellulosome is a cellulolytic MEC produced by anaerobic bacteria that has been studied extensively since its discovery in 1983. The aim of this study was to purify a cellulolytic and/or hemicellulolytic MEC from an aerobic bacterium of the Bacillus genus. Several bacterial isolates were identified using morphological characteristics and 16S rDNA sequencing, and screened for their ability to degrade cellulose and xylan using a MEC. The isolate that produced a high molecular weight protein fraction with the greatest ability to degrade Avicel®, carboxymethyl cellulose (CMC) and birchwood xylan was identified as Bacillus subtilis SJ01. An optimised growth medium, consisting of vitamins, trace elements, birchwood xylan (as the carbon source), and yeast and ammonium sulphate (as the nitrogen sources), increased the production of CMCase and xylanase enzymes from this bacterium. The removal of a competing bacterial strain from the culture and the inhibition of proteases also increased enzyme activities. A growth curve of B. subtilis SJ01 indicated that xylanase production was highest in early stationary growth phase and thus 84 hours was chosen as the best cell harvesting time. To purify the MECs produced by B. subtilis SJ01 size-exclusion chromatography on a Sephacryl S-400 column was used. It was concluded that (for the purposes of this study) the best method of concentrating the culture supernatant prior to loading onto Sephacryl S-400 was the use of ultrafiltration with a 50 kDa cut-off membrane. Two MECs, named C1 and C2 of 371 and 267 kDa, respectively, were purified from the culture supernatant of B. subtilis SJ01. Electrophoretic analysis revealed that these MECs consisted of 16 and 18 subunits, respectively, 4 of which degraded birchwood xylan and 5 of which degraded oat spelt xylan. The MECs degraded xylan substrates (C1: 0.24 U/mg, C2: 0.14 U/mg birchwood xylan) with higher efficiency than cellulose substrates (C1: 0.002 U/mg, C2: 0.01 U/mg CMC), and could therefore be considered xylanosomes. Interestingly, the MECs did not bind to insoluble birchwood xylan or Avicel® and did not contain glycosylated proteins, which are common features of cellulosomes. This study is, therefore, important in revealing the presence of MECs that differ from the cellulosome and that may have particular application in industries requiring high xylanase activity, such as the paper and pulp industry. The abundant genetic information available on B. subtilis means that this organism could also be used for genetic engineering of cellulolytic/hemicellulolytic MECs.