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Yu Yun Lung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 101-114). / Abstracts in English and Chinese. / Acknowledgments / Abstract / Table of Contents / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1 / Chapter 1.1 --- General Structure of Lectins --- p.1 / Chapter 1.1.1 --- Metal Binding Sites --- p.2 / Chapter 1.1.2. --- Hydrophobic Sites --- p.3 / Chapter 1.1.3. --- Glycosylation Sites --- p.3 / Chapter 1.2 --- Carbohydrate Specificities of Lectins --- p.4 / Chapter 1.3 --- Plant Lectins --- p.4 / Chapter 1.3.1 --- Localization of lectins in plants --- p.4 / Chapter 1.3.1.1 --- Localization in seeds --- p.4 / Chapter 1.3.1.2 --- Localization in vegetative parts --- p.5 / Chapter 1.3.1.3 --- Biosynthesis of plant lectins --- p.6 / Chapter 1.3.2 --- Functions of plant lectins in plants --- p.7 / Chapter 1.3.2.1 --- In cell growth --- p.7 / Chapter 1.3.2.2 --- In storage --- p.8 / Chapter 1.3.2.3 --- In plant defence --- p.8 / Chapter 1.3.2.4 --- In nitrogen cycle --- p.10 / Chapter 1.3.3 --- Biological activities of plant lectins in other organisms --- p.13 / Chapter 1.3.3.1 --- Immunomodulatory activity --- p.13 / Chapter 1.3.3.2 --- Antitumor and antiproliferative activities --- p.14 / Chapter 1.3.3.3 --- Mitogenic activity --- p.14 / Chapter 1.3.3.4 --- Antiviral activity --- p.14 / Chapter 1.3.4 --- Relationship between lectins and ribosome inactivating proteins: family of ricin-related proteins --- p.16 / Chapter 1.3.5 --- Applications of plant lectins --- p.18 / Chapter 1.3.5.1 --- In scientific research --- p.18 / Chapter 1.3.5.2 --- In medical research --- p.19 / Chapter 1.4 --- Animal Lectins --- p.20 / Chapter 1.4.1 --- Some properties of animal lectins --- p.20 / Chapter 1.4.2 --- Functions of animal lectins --- p.22 / Chapter 1.4.2.1 --- In protein metabolism --- p.22 / Chapter 1.4.2.2 --- As a mediator of binding and phagocytosis of microorganisms --- p.22 / Chapter 1.4.2.3 --- Control of differentiation and organ formation --- p.23 / Chapter 1.4.2.4 --- Lectins and migration of lymphocytes --- p.23 / Chapter 1.4.2.5 --- Lectins and metastasis --- p.24 / Chapter 1.5 --- Mushroom lectins --- p.25 / Chapter 1.6 --- Regulation of lectins --- p.29 / Chapter 1.7 --- Isolation and purification of lectins --- p.31 / Chapter 1.8 --- Objectives of the present study --- p.33 / Chapter CHAPTER 2 --- "SCREENING FOR HEMAGGLUTINATING ACTIVITY IN EXTRACTS OF SEEDS, FRUITS, VEGETABLES AND CHINESE MEDICINAL HERBS" --- p.35 / Chapter 2.1 --- Introduction --- p.35 / Chapter 2.2 --- Materials and methods --- p.36 / Chapter 2.3 --- Results --- p.38 / Chapter 2.4 --- Discussion --- p.38 / Chapter CHAPTER 3 --- ISOLATION OF LECTIN FROM RHIZOMES OF SMILAX GLABRA (FAMILY LILIACEAE) --- p.43 / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.1.1 --- Introduction about Smilax glabra and its chemical constituents --- p.43 / Chapter 3.1.2 --- Introduction about monocot lectins including Liliaceae lectins --- p.45 / Chapter 3.2 --- Materials and methods --- p.50 / Chapter 3.2.1 --- Isolation of lectins from Smilax glabra rhizomes --- p.50 / Chapter 3.2.2 --- Assay for hemagglutinating activity --- p.55 / Chapter 3.2.3 --- Test of inhibition of lectin-induced hemagglutination by various carbohydrates --- p.55 / Chapter 3.2.4 --- "Effects of acid, alkali, temperature and cations on hemagglutinationg activity of lectin" --- p.56 / Chapter 3.2.5 --- Determination of protein concentration --- p.56 / Chapter 3.2.6 --- Molecular mass determination by SDS-PAGE --- p.56 / Chapter 3.2.7 --- Molecular mass determination by gel filtration --- p.56 / Chapter 3.2.8 --- Amino acid sequence analysis --- p.57 / Chapter 3.3 --- Results --- p.57 / Chapter CHAPTER 4 --- ISOLATION OF LECTIN FROM SEEDS OF THE CHINESE CHESTNUT CASTANEA MOLLISIMA (FAMILY FAGACEAE) --- p.74 / Chapter 4.1 --- Introduction to Castanea mollisima and its chemical constituents --- p.74 / Chapter 4.2 --- Materials and Methods --- p.78 / Chapter 4.2.1 --- Isolation of lectin from Chinese chestnuts --- p.78 / Chapter 4.2.2 --- Assay for hemagglutinating activity --- p.83 / Chapter 4.2.3 --- Test of inhibition of lectin-induced hemagglutination by various carbohydrates --- p.83 / Chapter 4.2.4 --- "Effects of acid, alkali, temperature and cations on hemagglutinationg activity of lectin" --- p.83 / Chapter 4.2.5 --- Determination of protein concentration --- p.83 / Chapter 4.2.6 --- Molecular mass determination by SDS-PAGE --- p.83 / Chapter 4.2.7 --- Molecular mass determination by gel filtration --- p.83 / Chapter 4.2.8 --- Amino acid sequence analysis --- p.83 / Chapter 4.3 --- Results --- p.84 / Chapter 4.4 --- Discussion --- p.96 / Chapter CHAPTER 5 --- GENERAL DISCUSSION AND CONCLUSION --- p.98 / REFERENCES: --- p.101

In anticipation of widespread planting of putatively blight-resistant hybrid chestnuts (Castanea spp.), it is critical to understand the silvics and competitive ability of the species. This dissertation examines preliminary growth and survival of several species and genetic crosses of chestnut grown as 1-0 high-quality nursery seedlings and planted in two study sites: Southeastern Kentucky (Daniel Boone National Forest; chapter 2), and Northeastern Connecticut (Yale-Myers Forest; chapter 4). The effects of three silvicultural treatments on the Daniel Boone National Forest (DBNF), and four silvicultural treatments on the Yale-Myers Forest (YM) were evaluated. Furthermore, the effect of initial seedling size on seedling performance was tested. In both studies, seedlings grew largest in height and root collar diameter in silvicultural treatments with the most available light. High mortality at the DBNF planting was caused by Phytophthora cinnamomi, ink disease, and high mortality at the YM planting was caused by repeated deer, Odocoileus virginianus, browsing and competition from hay-scented fern, Dennstaedtia punctilobula. Additionally, seedlings at the DBNF study were repeatedly defoliated by Craesus castaneae, chestnut sawfly, during the first growing season (chapter 3). Seedlings with larger root collar diameters at planting demonstrated greater survival and growth in the DBNF study while seedlings larger in height and RCD added less growth and were more likely to die in the YM study, likely due to the high deer population and dense understory competition. These results indicate that silvicultural treatments that create high-light environments are ideal for chestnut, however the species can establish successfully under a variety of light conditions, from low light [10% photosynthetically active radiation (PAR)] to high light (65% PAR). Ink disease will present a formidable obstacle to chestnut reintroduction efforts in the south, while northern efforts will be challenged by deer browsing due to overpopulated deer herds.

American chestnut was once a crucial component of North American forests, but it was functionally eliminated by the introduction of the chestnut blight fungus. Chestnut is recently experiencing resurgence, but the introduced Asian chestnut gall wasp, a specialist herbivore, threatens chestnut recovery. I characterized this invasion and the interactions developing with host associates as the gall wasp spread in North America. Gall wasp dispersal is attributable to host plant distribution, effects of prevailing winds during adult insect emergence, and to topography. This knowledge may be useful to more accurately predict locations of future gall wasp infestations. Gall wasp invasiveness is also affected by its ability to modulate reproduction and reallocate nutritive resources for body maintenance and egg quality. The gall wasp can form galls of different shape and structure based on population levels and parasitism pressure, in order to optimize fitness. Simple, uni-lobed galls are formed when population pressure is low, and complex, multi-lobed galls are formed when gall wasp populations are high. A fungal plant pathogen, identified as Colletotrichum sp., infects galls and acts as an opportunistic entomopathogen, causing gall wasp mortality while sparing the parasitoid. A non-native torymid parasitic wasp has been deployed for biological control. Using a Y-olfactometer I demonstrated that a combination of olfactory and visual cues from chestnut galls and chestnut foliage is required for parasitoid adults to locate hosts. In addition, I evaluated interactions between the gall wasp and stem cankers on chestnut. Using potted Chinese chestnut seedlings with or without gall wasp or a native Nectria cankering pathogen, I found that the gall wasp has a negative impact on plant fitness, and a positive impact on fungal fitness. My work helps elucidate ecological mechanisms underlying the success of the exotic Asian chestnut gall wasp in North America, and adds to our knowledge base characterizing evolving ecological interactions between native and introduced species.

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Genetically modified (GM) cotton expressing Cry1Ac proteins was released in South Africa in 1997 for control of the bollworm complex on this crop. No reports of the failure of Bollgard® cotton to control these pests have yet been made. Throughout the world there are concerns about the development of resistance of target pests to Bt cotton due to the use of only one Bt gene. The aim of this study was to determine if Helicoverpa armigera (Lepidoptera: Noctuidae) and Diparopsis castanea (Lepidoptera: Noctuidae) developed resistance to Bt cotton in South Africa. To determine if H. armigera developed resistance, laboratory experiments were conducted to determine the levels of larval survival and development time when feeding on Bt and non–Bt cotton. Bollworm populations were collected on maize and cotton at different sites in South Africa and reared on Bt and non–Bt cotton under laboratory conditions. Results showed that some populations survived on Bt cotton and that a significant proportion of the individuals successfully completed their life cycles on Bt cotton. Surveys were also conducted amongst cotton farmers to determine the levels of compliance to the refuge strategy that has to be implemented by farmers as an insect resistance management (IRM) strategy to delay resistance development. The levels of compliance to refugia requirements were low and farmers generally only started planting refugia several years after they planted Bt cotton for the first time. The development of resistance of H. armigera to Bt cotton in South Africa can possibly be ascribed to non–compliance to the prescribed refuge requirements. No conclusions can be made on resistance of D. castanea to Bt cotton but the relatively long time to mortality of larvae could indicate development of tolerance to Cry1Ac proteins. The new generation Bollgard II® cotton, expressing both Cry1Ac and Cry2Ab2 proteins, has been released in South Africa during the 2010/11 growing season and field observations showed effective control of the bollworm complex at several sites in the country. Monitoring of refuge compliance levels as well as resistance development in the bollworm complex to Bollgard II® cotton is necessary to ensure the future success of GM cotton. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

Genetically modified (GM) cotton expressing Cry1Ac proteins was released in South Africa in 1997 for control of the bollworm complex on this crop. No reports of the failure of Bollgard® cotton to control these pests have yet been made. Throughout the world there are concerns about the development of resistance of target pests to Bt cotton due to the use of only one Bt gene. The aim of this study was to determine if Helicoverpa armigera (Lepidoptera: Noctuidae) and Diparopsis castanea (Lepidoptera: Noctuidae) developed resistance to Bt cotton in South Africa. To determine if H. armigera developed resistance, laboratory experiments were conducted to determine the levels of larval survival and development time when feeding on Bt and non–Bt cotton. Bollworm populations were collected on maize and cotton at different sites in South Africa and reared on Bt and non–Bt cotton under laboratory conditions. Results showed that some populations survived on Bt cotton and that a significant proportion of the individuals successfully completed their life cycles on Bt cotton. Surveys were also conducted amongst cotton farmers to determine the levels of compliance to the refuge strategy that has to be implemented by farmers as an insect resistance management (IRM) strategy to delay resistance development. The levels of compliance to refugia requirements were low and farmers generally only started planting refugia several years after they planted Bt cotton for the first time. The development of resistance of H. armigera to Bt cotton in South Africa can possibly be ascribed to non–compliance to the prescribed refuge requirements. No conclusions can be made on resistance of D. castanea to Bt cotton but the relatively long time to mortality of larvae could indicate development of tolerance to Cry1Ac proteins. The new generation Bollgard II® cotton, expressing both Cry1Ac and Cry2Ab2 proteins, has been released in South Africa during the 2010/11 growing season and field observations showed effective control of the bollworm complex at several sites in the country. Monitoring of refuge compliance levels as well as resistance development in the bollworm complex to Bollgard II® cotton is necessary to ensure the future success of GM cotton. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2012.

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