Bibliography: leaves 87-96. This thesis investigates non-proteinaceous low molecular weight flavonoid and alkaloid compounds in Scurulla oortiana (Korth.) Danser grown on Camellia sinens. Three flavonols are identified in S. oortiana (Korth.) Danser growing on different hosts. The identification and characterisation of these flavonoids are carried out using various chromatographic and spectrometric procedures. Two purine alkaloids are isolated from and identified in S. oortiana (Korth.) Danser parasitizing tea plant, C. Sinensis. The antifungal activity of the phenolic compounds isolated from mistletoe parasitizing tea plant is examined.

M. Tech. Chemistry. / Investigates the methods of preparing verbascoside-rich plant extracts, identifying viable sources of the compound and evaluating its stability under various conditions. Leaf extracts of Lippia javanica and Lantana camara (Verbenaceae) were partially purified using column chromatography and high speed centrifugal countercurrent chromatography.

Inhibition of Fusarium oxysporum f. sp. cubense race 4 by Burkholderia cepacia was evident when grown on various media (TSA, PDA, PSA, YM, KMB, PPM, NYGA, LA) with different carbon sources and under various pH and temperature conditions. In addition, B. cepacia was able to inhibit several fungal pathogens in vitro. Antagonism of B. cepacia against F. oxysporum f. sp. cubense occured at high levels of Fe³+, which may suggest that antagonism by B. cepacia did not involve siderophore production. Thin layer chromatogram (TLC) examination showed that B. cepacia produced several substances, one of which had similar R[f] value to that described for pyrrolnitrin. Cell-free supernatant of a 4-day culture of 6. cepacia was applied to an Amberlite XAD-2 column and inhibitory activity co-eluted with the 95% methanol (pH 9.5) fraction. The concentrated activated fractions showed inhibitory activity against F. oxysporum f. sp. cubense. A GC-MS chromatogram indicated numerous components in the antifungal extracts. The only compound identified in the Wiley 138 library, was 1,2- Benzenedicarboxylic acid, bis (2-Ethylhexyl) ester. Observations by light microscopy indicated that B. cepacia inhibited spore germination in F. oxysporum f. sp. cubense race 4 and retarded the mycelial growth. The interaction between the endophytic bacterium, B. cepacia and F. oxysporum f. sp. cubense race 4 was investigated with aid of scanning and transmission electron microscopy. This demonstrated that the bacterium was able to colonize the surface of hypha and macrospore of F. oxysporum f. sp. cubense. Mycelial deformation, terminal and/or intercalary swelling were evident. At later stages, hyphae of F. oxysporum f.sp. cubense, colonized by B. cepacia, were found to have collapsed. Further studies in vivo confirmed that B. cepacia colonized the hypha of F. oxysporum f. sp. cubense which had invaded banana roots. TEM observation showed that in the banana plant B. cepacia was closely associated with the healthy banana roots and a matrix was frequently found to be present between the bacterium and the plant surface. In addition, B. cepacia exists mainly in the intercellular space of the banana roots. UV irradiation treatment of B. cepacia resulted in a mutant that had lost inhibitory activity against F. oxysporum f. sp. cubense on TSA agar. Transposon mutagenesis of B. cepacia was performed by Tn5 insertion. Six mutants which had lost or had reduced inhibitory activity against F. oxysporum f. sp. cubense were generated. These mutants showed no inhibitory zones on TSA medium in the presence of the fungus. It was observed that one mutants. cepacia :: Tn5-188 appeared to lose the ability to colonize the fungal hypha, whilst a different mutant B. cepacia ::Tn5 - 217 was still able to colonize the fungal hyphae. TLC analyses showed that there was a decrease in antibiotic production in mutants B. cepacia :: Tn5 - 217 and B. cepacia - UV - 34, compared with the wild type. GC- MS analyses showed that there was no evidence of the peaks at 14.62 minutes, 20.0 minutes and 20.46 minutes in both chromatograms of mutants B. cepacia :: Tn5 -217 and 8. cepacia -UV - 34, compared with the wild type B. cepacia. No PCR products were detected using primers that were developed from sequences within the biosynthetic loci for Phi of P.fluorescens Q2-87(GenBank accession no. U41818) and PCA of P. fluorescens 2-79 (GeneBank no. L48616). Colony hybridization suggested that genomic DNA from B. cepacia could contain both Phi- and PCA probes. It was found that hybridization of genomic DNA digested with Cla-I of B. cepaca with Phl2a probe only occurred at low stringency. A hybridization signal was detected from a Cla-l fragment of approximately 2800bp. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

Thesis (M.Sc.). / Written for the Dept. of Biochemistry. Title from title page of PDF (viewed 2008/07/30). Includes bibliographical references.

Thesis (PhD) -- University of Western Sydney, 2007. / A thesis submitted to the University of Western Sydney, College of Health and Science, School of Natural Sciences, as a requirement for the degree of Doctor of Philosophy. Includes bibliography.

Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 129-156). Also available in electronic format on the Internet.

Thesis (D.P.H.)--University of Alabama at Birmingham, 2010. / Title from PDF title page (viewed on July 1, 2010). Includes bibliographical references.

The fungal infections are becoming an important cause of morbidity and mortality in immunocompromised patients. Here we have studied the activity of new antifungal agents as ravuconazole, albaconazole, micafungin as well as fluconazole tpathogenic yeasts as Candida albicans, Candida dubliniensis, Candida tropicalis, Candida lusitaniae, Candida glabrata and Candida krusei. We have also included clinical and environmental isolates of Cryptococcus neoformans. The susceptibilities tests indicated that the majority of the strains were sensible to the antifungal agents studied but Candida albicans (6.6%) and C.tropicalis (3.3%) were classified as resistant to fluconazole. These results show the importance of monitoring of the susceptibility in yeast like fungi from clinical source and emphasize that new and constant susceptibility studies deserve be applied to Candida and Cryptococcus neoformans to reduce the mortality among immunocompromised patients. / As infecções fúngicas têm-se tornado uma importante causa de morbidade e mortalidade em pacientes, principalmente os imunocomprometidos. Na tentativa de se transpor esta realidade, têm-se buscado estabelecer e avaliar novas drogas antifúngicas eficazes e com melhor tolerabilidade e segurança. O presente estudo foi objetivado a verificar a atividade dos triazólicos fluconazol, ravuconazol e albaconazol e da micafungina, frente a um banco de fungos leveduriformes incluindo as espécies C.albicans, C. dubliniensis, C. tropicalis, C. lusitaniae, C. glabrata e C. krusei, todas de origem clínica e Cryptococcus neoformans de origens clínica e ambiental. De modo geral, as espécies de Candida spp. e Cryptococcus foram sensíveis aos antifúngicos testados, com exceção da Candida albicans e Candida tropicalis frente ao fluconazol, onde 6,6% e 3,3%, respectivamente dos isolados, foram resistentes a este azólico. Estes resultados demonstram a necessidade de uma constante vigilância da suscetibilidade dos fungos e maiores pesquisas em relação às drogas antifúngicas, pois, desta forma, estaremos contribuindo para a menor morbidade e maior sobrevida dos pacientes.

Orientador: Carlos Eduardo Vergani / Resumo: Nos últimos anos, os microcristais de prata têm se tornado foco de estudos. Uma das propriedades evidenciadas destes materiais é a sua atividade antimicrobiana contra diferentes microrganismos, devido a presença da prata na sua composição. Neste estudo, investigou-se a atividade antifúngica de microcristais de alfa vanadato de prata (α-AgVO3) contra Candida albicans (ATCC 90028) e sua citotoxicidade sobre células do tipo queratinócitos orais normais espontaneamente imortalizados (NOK-si). Os microcristias de α-AgVO3 foram sintetizados pelo método da co-precipitação sob três diferentes temperaturas (10, 20 e 30ºC) e caracterizados através de difração de raios-x, microscopia eletrônica de varredura por emissão de campo e espectroscopia Raman. A atividade antifúngica foi avaliada a partir da microdiluição seriada dos microcristais (de acordo com o Clinical & Laboratorial Standards Institute - CLSI), onde foram determinadas as concentrações inibitória (CIM) e fungicida mínimas (CFM). Imagens de microscopia de fluorescência com os microcristais nas concentrações inibitória e fungicida mínimas foram obtidas a fim de confirmar os achados microbiológicos. A viabilidade celular de células NOK-si foi avaliada através do ensaio Alamar Blue, e imagens de microscopia eletrônica de varredura (MEV) de todos os grupos avaliados foram realizadas. Nos ensaios celulares foram utilizadas apenas quatro concentrações dos microcristais (CIM, CFM, CIM diluída 10 vezes e concentrada 10 vezes). Os r... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

No description available.