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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

Isolation, characterization, evaluation and mechanistic study of the antiproliferation fractions from shiitake (Lentinula edodes) exudates towards HL60 (acute promyelocytic leukemia) cell line. / CUHK electronic theses & dissertations collection

January 2008 (has links)
In this study, a novel compound was isolated and purified from the solid culture medium (potato dextrose agar) of shiitake 1358 strain through series of methods, such as ethanol precipitation, macroporous resin column separation, semi-preparative high performance liquid chromatography separation and preparative thin-layer chromatography separation. Analyzing spectra from fourier transform infra-red spectroscopy, gas chromatography-mass spectrometry, 1-dimension and 2-dimension nuclear magnetic resonance, the chemical structure of the novel compound was determined and named as 4-amino-5,6-dihydrobenzo[d]oxonine-2,7(1H,4H)-dione. It could inhibit the proliferation of HL-60 leukemia cells significantly and with an IC50 of 1.56 mug/ml (7.123 mumol/L) in the 72-hour treatment. From the results, it is suggested that this compound could activate the G2 phase checkpoint control of the cell cycle to arrest the cell cycle in G2 phase. In addition, it could suppress the replicative DNA synthesis to inhibit the proliferation of HL-60 leukemia cells. The more important is that this compound can induce the apoptosis of HL-60 leukemia cells significantly through intrinsic and extrinsic apoptotic pathways. The compound could induce intrinsic and extrinsic apoptosis through the regulation of the apoptosis-related proteins, such as Fas ligand, Bax, Bcl-2, Caspase 8, Caspase 9, and Caspase 3. For intrinsic pathway, the compound might upregulate Bax, downregulated Bcl-2, activated the Caspase 9, subsequently activated Capase 3, and ultimately led to cell death. For extrinsic pathway, the compound upregulated the Fas ligand, cleaved and activated Procaspase 8 to active Caspase 8, further cleaved and activated Procaspase 3 to active Caspase 3 to commit the cells to apoptosis. / Leukemia is a malignant cancer that involves the bone marrow and blood circulation systems. Leukemia results in the uncontrolled growth of abnormal (leukemic) white blood cells and may also invade other organs, including the liver, spleen, lymph nodes, testes, and brain. In 2007, about 44,240 new cases of leukemia were diagnosed and 21,790 patients died from all types of leukemias in USA. / Shiitake was first cultivated in China more than 800 years ago. It is the second most commonly cultivated edible mushrooms in the world nowadays. For a long time, shiitake has been valued for its unique taste and flavor and as a medicinal invigorant. According to ancient Chinese medicinal theory, consumption of shiitake was in favor of long life and good health. In China and Japan, shiitake has been used as both a food and a medicinal herb for thousands of years. It is the source of several well-studied preparations with proven pharmacological properties, especially the polysaccharide lentinan. Currently, most researches concentrate on the anticancer activities of the extracts from the fruiting body of shiitake, especially polysaccharides. Report about the anti-cancer effects of other components from the shiitake mushroom is scarce. The objectives of this investigations were: (1) to study the anticancer activities of brownish substances obtained during the solid medium culture of shiitake on specific cancer cell unes, especially HL60 cancer cell line; (2) to isolate and characterize the active compound(s) in the brown mushroom exudates; and (3) to propose the possible mechanism of actions, especially the function of the bcl-2 family genes and proteins. / by Guo, Yuming. / Adviser: Chung Hale Yin. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3314. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 188-199). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
2

Expressed sequence tags and functional characterization of fruiting genes during fruit body development of edible mushroom Lentinula edodes.

January 2000 (has links)
by Ng Tak Pan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 151-168). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Abbreviations --- p.v / Table of Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xiii / Chapter Chapter One --- Literature Review / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Nutraceutical and Medicinal Properties of L. edodes --- p.4 / Chapter 1.2.1 --- Nutritional value --- p.4 / Chapter 1.2.2 --- Hypocholesterolaemic Effect --- p.5 / Chapter 1.2.3 --- Anti-tumor Effect --- p.5 / Chapter 1.2.4 --- Anti-viral Effect --- p.6 / Chapter 1.2.5 --- Immunopotentiating Effect --- p.6 / Chapter 1.3 --- Life cycle of L. edodes --- p.7 / Chapter 1.4 --- Environmental factors affecting mycelial growth and fruit body --- p.11 / Chapter 1.4.1 --- Nutrient requirement --- p.11 / Chapter 1.4.2 --- Physical and chemical factors --- p.12 / Chapter 1.5 --- Molecular studies on mushroom development --- p.15 / Chapter 1.5.1 --- Mating-type genes --- p.15 / Chapter 1.5.2 --- Hydrophobins --- p.19 / Chapter 1.5.3 --- Fruiting regulatory genes --- p.23 / Chapter 1.5.4 --- Molecular studies on fruit body development of I. edodes --- p.24 / Chapter 1.5.4.1 --- Identification of L. edodes genes --- p.24 / Chapter 1.5.4.2 --- Functional characterization of L. edodes genes --- p.27 / Chapter 1.5.4.3 --- Transformation in L. edodes --- p.28 / Chapter Chapter Two --- Expressed Sequence Tags (ESTs) of L. edodes / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- Materials and Methods --- p.33 / Chapter 2.2.1 --- Generation of expressed sequence tag --- p.33 / Chapter 2.2.1.1 --- Mushroom cultivation and RNA extraction --- p.33 / Chapter 2.2.1.2 --- Construction of primordium cDNA library --- p.34 / Chapter 2.2.1.3 --- Mass excision of pBK-CMV plasmid --- p.34 / Chapter 2.2.1.4 --- Random screening of mass excised cDNA clone --- p.38 / Chapter 2.2.1.5 --- Isolation of recombinant plasmid --- p.38 / Chapter 2.2.1.6 --- Generation of 3´ة end partially sequence --- p.39 / Chapter 2.2.1.7 --- Sequence analysis --- p.40 / Chapter 2.2.2 --- Reverse dot-blot Hybridization --- p.40 / Chapter 2.2.2.1 --- PCR amplification of cDNA clone --- p.40 / Chapter 2.2.2.2 --- Membrane preparation --- p.40 / Chapter 2.2.2.3 --- cDNA probe preparation --- p.41 / Chapter 2.2.2.4 --- Hybridization --- p.42 / Chapter 2.2.2.5 --- Stringent washing and autoradiography --- p.43 / Chapter 2.3 --- Results --- p.44 / Chapter 2.3.1 --- Construction of primordium cDNA library --- p.44 / Chapter 2.3.2 --- Screening of recombinant clone --- p.44 / Chapter 2.3.3 --- Isolation and reconfirmation of recombinant plasmid --- p.46 / Chapter 2.3.4 --- Generation of EST --- p.47 / Chapter 2.3.5 --- EST identity --- p.47 / Chapter 2.3.6 --- Reverse dot-blot hybridization --- p.56 / Chapter 2.3.7 --- Analysis of hybridization signal --- p.60 / Chapter 2.4 --- Discussion --- p.71 / Chapter Chapter Three --- Sequence Analysis and Transcriptional Profiling of Genes Encoding GTP-binding Proteins / Chapter 3.1 --- Introduction --- p.78 / Chapter 3.2 --- Materials and Methods --- p.82 / Chapter 3.2.1 --- Sequence manipulation --- p.82 / Chapter 3.2.2 --- Northern blot hybridization --- p.82 / Chapter 3.2.2.1 --- RNA fragmentation by formaldehyde gel electrophoresis --- p.82 / Chapter 3.2.2.2 --- RNA fixation by capillary method --- p.83 / Chapter 3.2.2.3 --- Probe preparation --- p.84 / Chapter 3.2.2.4 --- Hybridization --- p.85 / Chapter 3.2.2.5 --- Stringent washing and autoradiography --- p.85 / Chapter 3.2.3 --- Real-Time SYBR Green RT-PCR --- p.85 / Chapter 3.2.3.1 --- Primer design --- p.85 / Chapter 3.2.3.2 --- RT-PCR reaction --- p.86 / Chapter 3.3 --- Results --- p.88 / Chapter 3.3.1 --- Sequence manipulation --- p.88 / Chapter 3.3.2 --- Transcriptional analysis --- p.103 / Chapter 3.4 --- Discussion --- p.108 / Chapter 3.4.1 --- Heterotrimeric G proteins --- p.108 / Chapter 3.4.2 --- Ras-related protein Rab7 --- p.112 / Chapter 3.4.3 --- Developmentally regulated GTP-binding protein --- p.113 / Chapter Chapter Four --- Yeast Complementation and Over-expression tests of Le.Gβ1 and Le.Gγ1 / Chapter 4.1 --- Introduction --- p.115 / Chapter 4.2 --- Materials and Methods --- p.120 / Chapter 4.2.1 --- "Yeast strains, media and yeast vectors" --- p.120 / Chapter 4.2.2 --- Primer design --- p.121 / Chapter 4.2.3 --- RT-PCR Amplification of Le.Gβ1 and Le.Gγ1 --- p.121 / Chapter 4.2.4 --- Purification of PCR products --- p.122 / Chapter 4.2.5 --- Enzymatic digestion and purification --- p.122 / Chapter 4.2.6 --- Ligation and E. coli transformation --- p.122 / Chapter 4.2.7 --- PCR screening of E. coli transformants --- p.124 / Chapter 4.2.8 --- Plasmids extraction --- p.124 / Chapter 4.2.9 --- Yeast transformation --- p.124 / Chapter 4.2.10 --- Mating test --- p.125 / Chapter 4.3 --- Results --- p.129 / Chapter 4.3.1 --- Cloning of Le.Gβ1 and Le.Gγ1 --- p.129 / Chapter 4.3.2 --- Yeast transformation --- p.129 / Chapter 4.3.3 --- Mating test --- p.130 / Chapter 4.4 --- Discussion --- p.141 / Chapter Chapter Five --- General Discussion --- p.144 / References --- p.151

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