Graduation date: 1992

UDP-glucose, the precursor for cellulose biosynthesis, can be produced via the catalysis of sucrose by sucrose synthase (SuSy) or through the phosphorylation of glucose-I-phosphate by UDP-glucose pyrophosphorylase (UGPase). As such, these genes, together with sucrose phosphate synthase (SPS) which recycles fructose (an inhibitor of SuSy), are interesting targets for altering carbon allocation in plants. In an attempt to alter cell wall biosynthesis in plants, targeted overexpression of SuSy, UGPase and SPS independently and in a pyramiding strategy was assessed in tobacco. All lines displayed enhanced growth and biomass production, and in the case of double and triple transgenics, there was an additive effect. Despite the increased growth rates, there was no consistent change in soluble carbohydrate pools. Furthermore, only the triple transgenics had constant changes in structural carbohydrates: with increased hemicellulose content and slight increases in cellulose. Collectively, these results support the role of SPS, SuSy and UGPase in maintaining sink strength, but suggest that the reallocation of carbon to cellulose production in tobacco may not be possible by overexpressing these genes. In contrast, transgenic poplar overexpressing UGPase produced significantly more cellulose than wild-type trees. However, this was accompanied by a severe reduction in growth and the production of a salicylic acid glucoside (SAG) in significant quantities. The UDP-glucose generated by UGPase overexpression appeared to participate in both the synthesis of cellulose and SAG, suggesting that cellulose biosynthesis may be limited by the cellulose synthase complex. Poplar transformed with SuSy and with SuSy x UGPase also had increased cellulose production. The trees were phenotypically normal, with only minor reductions in height growth in some lines. It appears that UDP-glucose may be channelled directly to the cellulose synthase complex by SuSy. The increased cellulose content was associated with an increase in cell wall crystallinity, but there was no change in microfibril angle, confirming the re-allocation to cellulose synthesis was not the result of tension wood formation, again supporting the hypothesis that the cellulose synthase complex is the limiting factor. Clearly, it is possible to alter cellulose deposition in trees by augmenting sucrose metabolism to produce UDP-glucose, the precursor to cellulose biosynthesis.

Using data from OECD countries, one can investigate the effect of cultural diversity on anti-smoking policies. We use panel data models to test the impact of culture on the effectiveness of anti-smoking policies. It is assumed that two forces are effecting tobacco consumption in a society. These forces can be smoke preventive and smoke encouraging factors. Each of these forces consists of smaller subsets. Preventive policies and the time effects are the main parts of the smoke preventive forces. Culture and its effect on personal capital and social capital can be a part of smoke encouraging or smoke preventive forces. Using different proxies for culture and fixed effect models, this study allows one to investigate the differences in effectiveness of public policies in different OECD countries. The results from empirical investigation indicate that effectiveness of public policies depends on culture, therefore varies across countries. This is important for policymakers who need to avoid imposing uniform policies across a region with cultural diversity without accounting for cultural differences.

Local tobacco industry has developed for a hundred years since Taiwan under Japanese governed, it was once the main fiscal income source of the state. Coming after the facts of the formation of the global tobacco market, the affiliation to the World Trade Organization of Taiwan and the change of Taiwan Tobacco and Wine Monopoly Bureau to Taiwan Tobacco and Liquor Corporation, the statement of globalists which claims that the role of state declined becomes overwhelming. But according to this research, the tobacco industry in Taiwan actually has been nurtured by the state. From farmers growing tobacco leaf to consumers using the tobacco product, the state has the related norms and institutions to rule. Especially the period of Japanese government and the early retrocession of Taiwan, governments sought to pursue the fiscal income. For the reason of fiscal income, they controlled the whole tobacco industry from growing, harvest, marketing and consumption of tobacco. After the Sino-US agreement on tobacco and alcohol, the social anti-tobacco consciousness was awakened. The state also recognized the importance of the health of people. On the one hand, the state has to look after the rights of people who don't smoke, on the other, to consolidate the righteousness and the legitimacy of governing. In other words, the role of state doesn't decline for the part of tobacco industry in Taiwan, on the contrary, the state intervenes because of different goals. This thesis applies the theory of state-centered as the main research approach, to investigate the development of the tobacco industry in Taiwan, and compares the different focal points of interventions of the state. Otherwise, this thesis also emphasizes the interaction of the state, the domestic society and the international system, the interaction of the foregoing actos will shape the goals of the state.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 296-319).

Thesis (M. Nurs.)--University of Hong Kong, 2002. / Title from title frame. Includes bibliographical references (leaves 107-117).

No description available.

No description available.

The physical structure of the chloroplast DNA of Nicotiana tabacum has been characterized. This chloroplast DNA like other chloroplast DNAs, can be isolated as covalently closed circular molecules on CsCl-ethidium bromide gradients. Electron microscopy was used to measure the contour lengths of nicked circular chloroplast DNA molecules. N. tabacum chloroplast DNA is 28.8 times the size of phi X174. This measurement agrees reasonably well with the 96 megadalton molecular weight obtained by restriction enzyme analysis. Digestion with Sal I restriction enzyme produces 10 fragments each of which are unique in molecular weight and range in size from 1.8 to 17.0 megadaltons. A map of these sites relative to the location of the 18 Sma I fragments has been constructed. A technique utilizing the separation of double digests in two dimensions is the primary source of mapping data. This technique has also assigned the location of most of the Xba I sites. Restriction mapping and hybridization experiments have revealed that not all of this 45 um circle is unique DNA. Approximately 15 megadaltons is present in two copies. These duplicated segments contain the genes for ribosomal RNAs and are arranged in an inverted orientation to each other. The mapping of 16S and 23S rRNA was accomplished by utilizing this restriction map and the Southern hybridization technique. The results described indicate that there may be a non-coding interruption (an intron) in the 23S gene. Further investigation is needed to confirm this conclusion. Hybridization of 125-iodine labeled 16S and 23S rRNA to various restriction enzyme digests has allowed mapping of all of the Kpn I, Xba I, Bam HI and Eco RI fragments which contain DNA sequences complimentary to these rRNAs. These data, combined with the Sal I, Sma I, Xba I restriction map, produces a total of 70 sites whose locations on chloroplast DNA have been determined. The coding capacity of the N. tabacum chloroplast DNA genome has been estimated with the utilization of a new technique for assaying gene numbers. This technique, called the ribosome binding method, utilizes the recently discovered phenomenon that single stranded DNA will substitute for messenger RNA in the in vitro formation of initiation complexes. Results of experiments in which the ribosome binding sites of denatured chloroplast DNA have been saturated indicate that the N. tabacum chloroplast DNA may contain the coding sequences for as many as 200 distinct polypeptides. Ribosome DNA complexes visualized by electron microscopy produce structures which contain an average of approximately 2 ribosomes per 10 megadaltons. In conclusion the experiments and characterizations described reveal that N. tabacum chloroplast DNA has many features which are common to several higher plant chloroplast DNAs.

Fat body tissue was taken from female Manduca larvae throughout the fifth instar. The samples were prepared for histological study and electron microscopy. Hemolymph samples were collected and analyzed for protein profile and concentration. The data showed that the fat body underwent a series of changes with development. These include an increase in cell size, and accumulation of lipid and glycogen during the feeding phase of the instar, and the formation of protein and urate granules during the wandering stage. Also apparent was the cyclic development of a reticular system on the cell surfaces. Maximum development of the system coincided with the period of highest protein concentration in the hemolymph, while its disappearance is coincident with a drop in hemolymph protein concentration and formation of fat body granules. Thus the fat body plays a synthetic role early in the instar and becomes a storage tissue as pupation approaches.