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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

Genetical studies of the cultivated mushroom Lentinus edodes.

January 1990 (has links)
by Chan Ngar Lei Annie. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 90-102. / ACKNOWLEDGEMENTS --- p.i / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / LIST OF FIGURES --- p.vii / LIST OF TABLES --- p.ix / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 2. --- LITERATURE REVIEW --- p.5 / Chapter 2.1 --- Economic and Biotechnological Significance of Lentinus edodes --- p.5 / Chapter 2.1.1 --- General Review --- p.5 / Chapter 2.1.2 --- Nutritional and Medicinal Values --- p.7 / Chapter 2.1.3 --- Lignocellulose Degradation and Utilization --- p.9 / Chapter 2.2 --- Biological Background --- p.11 / Chapter 2.2.1 --- Life Cycle --- p.11 / Chapter 2.2.2 --- Patterns of Sexuality --- p.12 / Chapter 2.3 --- Genetic Improvement of Lentinus edodes --- p.16 / Chapter 2.3.1 --- Introduction --- p.16 / Chapter 2.3.2 --- Mutagenic Agents --- p.17 / Chapter 2.3.3 --- Genetic Markers and Strain Improvement --- p.20 / Chapter 3. --- MATERIALS AND METHODS --- p.24 / Chapter 3.1 --- Biological Materials --- p.24 / Chapter 3.2 --- Media --- p.25 / Chapter 3.2.1 --- Complete Medium (CM) --- p.25 / Chapter 3.2.2 --- Complete Medium with Yeast Extract (CM with Y.E.) --- p.25 / Chapter 3.2.3 --- Complete Fruiting Medium (CF) --- p.25 / Chapter 3.2.4 --- Complete Migration Medium (CMM) --- p.25 / Chapter 3.2.5 --- Minimal Medium (MM) --- p.25 / Chapter 3.2.6 --- Carboxymethyl Cellulose - Leatham Medium (CMC - Leatham) --- p.26 / Chapter 3.2.7 --- Potato Dextrose Agar (PDA) --- p.26 / Chapter 3.3 --- Anti-metabolites for Screening of Resistant Mutants --- p.27 / Chapter 3.4 --- Characterization of Monokaryons --- p.28 / Chapter 3.4.1 --- Isolation of Monosporous Mycelia --- p.28 / Chapter 3.4.2 --- Assessment of Mycelial Growth --- p.28 / Chapter 3.4.3 --- Determination of Mating Type of Monosporous Mycelia --- p.28 / Chapter 3.5 --- Mutagenesis and Isolation of Mutants --- p.29 / Chapter 3.5.1 --- Effects of Homogenization on Growth --- p.29 / Chapter 3.5.2 --- Determination of the Ultraviolet Irradiation Killing Curve --- p.29 / Chapter 3.5.3 --- Isolation of High Temperature Tolerant Strains --- p.30 / Chapter 3.5.4 --- Isolation of Auxotrophic Mutants --- p.30 / Chapter 3.5.5 --- Isolation of Anti-metabolite Resistant Mutants --- p.33 / Chapter 3.6 --- Characterization of Anti-metabolite Resistant Mutants --- p.33 / Chapter 3.6.1 --- "Measurements of Growth Rate, Anti-metabolites Resistance and Osmotic Sensitivity" --- p.33 / Chapter 3.6.2 --- Determination of Dominance Relationships --- p.34 / Chapter 3.6.3 --- Detection of Extracellular Enzymes --- p.34 / Chapter 4. --- RESULTS --- p.36 / Chapter 4.1 --- Radial Growth Rate of Monosporous Cultures --- p.36 / Chapter 4.2 --- Mating Reactions in Lentinus edodes --- p.36 / Chapter 4.3 --- Effects of Homogenization on Growth of L. edodes --- p.46 / Chapter 4.4 --- Determination of Ultraviolet (UV) Killing Curve --- p.46 / Chapter 4.5 --- Selection of High Temperature Tolerant Strains --- p.50 / Chapter 4.6 --- Auxotrophic Mutants Isolation and Identification --- p.50 / Chapter 4.7 --- Selection of Anti-metabolite Resistant Mutants --- p.52 / Chapter 4.8 --- Characterization of Cycloheximide Resistant Mutants V --- p.63 / Chapter 4.8.1 --- "Growth Rate, Anti-metabolite Resistance and Osmotic Sensitivity of Cycloheximide Resistant Mutants" --- p.63 / Chapter 4.8.2 --- Dominance Tests for Cycloheximide Resistant Strains --- p.66 / Chapter 4.8.3 --- Detection of Extracellular Enzymes --- p.73 / Chapter 5. --- DISCUSSION --- p.78 / Chapter 5.1 --- Mating Reactions in Lentinus edodes --- p.78 / Chapter 5.2 --- Isolation of Auxotrophic and Anti-metabolites Resistant Mutants --- p.81 / Chapter 5.3 --- Characterization of Cycloheximide Resistant Mutants of Lentinus edodes --- p.84 / CONCLUSION --- p.88 / REFERENCES --- p.90
2

Biology and management of a mushroom-infesting sciarid fly (Diptera: Sciaridae) in relation to room-to-room dispersal

Mehelis, Christopher N. 30 August 1995 (has links)
The purpose of this research is two fold. First to improve pest management of the sciarid fly (Diptera: Sciaridae) by better defining its relation to mushroom production. Secondly, to explore some of the factors and aspects of the biology of the fly which may increase room to room dispersal rates of adults. The effects of different generations of production room Lycoriella mali Fitch infestations and seasons on yield were explored. In models regressing densities of different generations to mushroom yield, significant negative slopes (p=.05) existed in all models. However, flies did not account for as much yield variance as hypothesized (16.43%). Yield is greatest during the winter months when insect pressure is lowest and decreases in summer months when more insects are present. Diflubenzuron (Dimilin 25 WP, Uniroyal Co.) was tested for its effects on fly emergence and oviposition. Diflubenzuron was effective in suppressing fly emergence and remained effective when treated compost was exposed to phase II peak heating. In production room experiments all fly generations had significantly fewer flies in rooms treated with diflubenzuron at fill. L. mali showed a slight preference to oviposition in diflubenzuron treated compost, indicating a possible attractant effect. A criterion table was developed to estimate the age of L. mali. Both younger and larger L. mali carried more ovarioles. The number of ovarioles that L. mali carry dropped significantly after 48 h; this is likely the time the fly becomes parous. The effects of ambient temperature and distance between production rooms on dispersal were explored. The greatest number of dispersing flies were caught during the summer months. As the daily median temperature increased, the number of dispersing flies increased exponentially. Production room blocks on the perimeter of the farm generally had fewer dispersing flies than centrally located production room blocks indicating that it was unlikely that a reservoir population existed outside the farm. Measurements of wing area and age of L. mali captured while dispersing and not dispersing were compared. Dispersing flies had significantly smaller wings than non-dispersers (p=.000). Wing area for dispersing flies decreased along a density gradient, while wing area for non-dispersers did not. The mean age of dispersing flies was not significantly different (p=.082) from non-dispersers, and neither changed along a density gradient. / Graduation date: 1996
3

Inhibition of anomalous retinal pigment epithelial cell activities, anin vitro study for the effects of 5-fluorouracil and Agaricus bisporuslectin

Cheung, Yiu-him., 張耀謙. January 2012 (has links)
  Proliferative vitreoretinopathy (PVR) remains the major cause of failure of retinal detachment surgery. Retinal pigment epithelial (RPE) cells have been suggested to play a major role in the pathogenesis of PVR. Numerous studies have employed pharmacological means to modulate cellular activities in attempts to inhibit the process. Recent attempts using adjunctive therapy during PVR surgery that consisted of 5-fluorouracil (5-FU) and low molecular weight heparin showed some promise in preventing PVR but the concern is that prolonged 5-FU treatment may have a toxic effect. On the other hand, lectin from the edible mushroom Agaricus bisporus (ABL) was found to inhibit growth of RPE cells in a potent manner without apparent cytotoxicity. This lectin could be a candidate to modulate anomalous proliferation of RPE cells while the mechanism for the observed inhibition is unknown.   In our study, we investigated whether RPE cells treated with 5-FU or ABL would attenuate cellular proliferation, cell migration, cell adhesion and cell-mediated contraction rates. Further, we investigated if complementary inhibition for the above cellular activities could be obtained when RPE cells were treated with ABL after the short treatment using 5-FU. We also explored the possible mechanisms through which ABL inhibited RPE cell proliferation.   ARPE-19 and primary human RPE cells were treated with 5-FU or vehicle for 10 minutes. Cells were then maintained in culture medium supplemented with or without ABL. The rate of cellular proliferation was measured by a tetrazolium salt assay. Effects on cell adhesion were investigated through loading RPE cells onto the strips coated with collagen I or fibronectin. Cell migration was investigated using a scratch wound model. The effect on cell-mediated contraction was assessed using a free floating collagen I matrix. Cytotoxicity of 5-FU and ABL was determined by the live/dead assay.   To elucidate the mechanism through which ABL inhibited RPE cell proliferation, we investigated cell cycle distribution patterns using flow cytometry. Phosphorylation statuses of Erk, Jnk, p38, Akt as well as p53 and Cyclin D expression level were investigated by Western blotting.   Both 5-FU and ABL inhibited RPE cell proliferation. Only ABL promoted cell adhesion towards collagen I in hRPE3 cells. ABL was found to attenuate the rate of cell migration. Cell-mediated collagen gel contraction was attenuated by 5-FU only. Complementary inhibition in cellular proliferation and cell-mediated collagen gel contraction was observed when both 5-FU and ABL were applied. No significant cell death was observed after treatment with 5-FU, ABL or both.   ABL was found to reduce the amount of cells present at S phase. Akt and Erk were found to be hypo-phosphorylated and hyper-phosphorylated respectively after ABL treatment. The expression levels of phosphorylated-Jnk, phosphorylated-p38, p53, and Cyclin D1 were not altered when compared with the control.   These results showed that 5-FU and ABL complement with each other on inhibiting the wound healing activities of RPE cells in vitro without apparent cytotoxicity. They suggested a possible new treatment modality for PVR. ABL hypo-phosphorylated Akt and this observation is in line with the fact that ABL could attenuate cell proliferation. / published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy
4

Arylhydrazine carcinogenesis and the synthesis of C8-arylpurine oligonucleotides a study of DNA adduct affects on DNA conformation and stability /

Daft, Jonathan R., January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xi, 323 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 191-211).
5

Fungal and substrate-associated factors affecting lignocellulolytic mushroom cultivation on wood sources available in South African [i.e. Africa]

Da Serra, Maria Fatima January 1997 (has links)
Vast- quantities of lignocellulosic materials, representing potential substrates for the cultivation of speciality mushrooms, are produced annually in South Africa. A number of these materials are derived as waste products of the timber and agricultural industries, e.g. Maranti (Shorea spp.) and Port Jackson Willow (Acacia longifolia) respectively. The screening of various wood-degrading fungi, which are cultivated worldwide for their production of speciality mushrooms, indicated that under the environmental conditions considered, certain species were adapted to cultivation on these lignocellulosic wastes (Pleurotus species) whereas others were not (Lentinus edodes and Flammulina velutipes). Furthermore, intra- and interspecies specific differences in the growth and production potential of the various lignocellulolytic fungi investigated on synthetic and natural medium were discovered. Biochemical and genetical investigations of these strains indicated differences between and within species which were often significant. Species varied qualitatively and quantitatively in the lignocellulolytic enzymes produced, which was loosely correlated with productivity on the different media investigated. Genetical studies, using RAPD fingerprinting, indicated that the Pleurotus genus is highly variable which supports the observed differences in growth, yield and enzymatic activity between different strains and species.

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