• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 130
  • 74
  • 14
  • 12
  • 10
  • 9
  • 8
  • 8
  • 7
  • 6
  • 5
  • 3
  • 2
  • 2
  • 2
  • Tagged with
  • 342
  • 300
  • 85
  • 78
  • 77
  • 55
  • 50
  • 36
  • 34
  • 34
  • 31
  • 31
  • 29
  • 27
  • 27
  • 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.
51

Genetically modified food and crops : perceptions of risks

Hall, Clare R. January 2010 (has links)
The debate around genetically modified food and crops has proved to be complex and far-reaching, involving diverse stakeholder groups and many issues. Although the extent of global uptake of GM crops has been substantial (23 countries and 114.65 million hectares by 2007), it is significant that four countries are responsible for 86% of all GM plantings, and that a number of key food markets (for example the EU and Japan) remain largely "GM-free‟. This suggests that there is reluctance on the part of many countries to embrace GM technology. There are likely many reasons for this, but one significant issue is that of the perception of the risks associated with the technology. There is a distinction between risk that exists in the world and that can be measured (objective risk) and risk that is perceived by an individual to exist and that is constructed by them based on their values and preferences. When technical measurement of actual risks is not possible, peoples‟ own perceptions of risks become important. This thesis aims to investigate the topic of risk perceptions associated with GM food and crops. Different stakeholder groups have been targeted, and a range of methodologies from a variety of disciplines have been employed to investigate what factors can be shown to influence risk perception. A range of factors were identified from existing literature, as having potential impact on risk perceptions. A number of these were investigated, some of which were found to have some influence on levels of risk perception. Results demonstrate that factors influencing peoples‟ perceptions of risk relating to GM food and crops, include the uncertainty associated with the technology, and trust in regulators, policy makers and others with control over the future development of the technology. Other factors found to be important to levels of risk perception held by different stakeholder groups, were a range of socio-demographic and cultural variables, the relationship between perceived risks and benefits, the equity of impacts, and the influence of third parties. There are a number of implications for the development of the GM debate arising from the findings. First, as there are socio-demographic and cultural factors linked to the perceptions of risk associated with GM technologies in food and agriculture, it is important to recognise that different people will react differently to the technology. Specifically, results from this thesis show that it may be that men, those who are more highly educated, those with a less ecocentric worldview, and those living in urban areas, are likely to respond more favourably to targeted promotional campaigns. As regards the farming community, results show that the first farming adopters are likely to be those who are both owners and tenants, not in an urban fringe location, potato growers, and not barley growers. Second, this thesis provides evidence that third parties are particularly important to farmers, thus it is crucial to recognise that there is potentially a long chain of action and reaction amongst many different stakeholders and actors impacting on farmers' levels of risk perception, and hence willingness to adopt the technology. Third, results from this research demonstrate that the linked issues of the relationship between risks and benefits, and the equity of (positive and negative) impacts, require that all stakeholders are content that they will receive a share of the benefits (if any) to be derived from the technology, and that neither they nor any other group of stakeholders are unduly impacted by the risks or negative impacts (if any) of the technology. Important here is the recognition that perceptions are as important as actual impacts. Fourth, the issue of trust has been shown by the results obtained by this research to be extremely important to peoples' perceptions of risk. It can be concluded that trust is of wider social and political importance that relates to the need to ensure greater democratisation of decision-making in order to re-establish trust in authorities. In the case of GM food this may require a rethinking of the EU legislation relating to the technology. This also relates to point below about the delivery of messages and education. Information sources must be trusted by those at whom the messages are aimed. More importantly though, if people are to trust decision making processes, there needs to be stakeholder involvement at an early stage of decision making, that allows some impact on decisions taken. In the case of the GM debate it may indeed be too late as decisions about the technology, its applications, the regulatory processes and its inclusion within the food chain are well established. Perhaps the best that can be hoped for is that lessons will be learnt and applied to future technology developments of relevance to the food chain, such as, nano-technology. Finally, this thesis has shown that uncertainty is central to peoples' perceptions of risk. This could be addressed through a combination of additional research into what is uncertain to people, the impacts and implications of the technology, more effective dissemination of existing knowledge, and impartially delivered messages and education strategies from trusted sources that address the concerns that people have about the technology. Importantly however there must be an acknowledgement that uncertainty is not restricted to "knowledge deficit‟ but encompasses the scientific uncertainties inherent within the technology, and is framed by the social and cultural values of those whose views are considered. This thesis uniquely targeted diverse groups and employed a combination of different methods from a variety of disciplines. By doing this the study has increased understanding of the views of two groups (campaigners and farmers) who are crucial to the uptake of the technology, and who are seldom researched in the area of attitudes to GM technologies. The diversity of groups, methods and disciplines brought together in this thesis is important because the issue of GM has proved to be complex and far-reaching, and previous discussions of risk perceptions have been complex and disjointed. All groups investigated here are stakeholders in the process, and as such their views and concerns relating to risk perceptions of GM technologies ought to be taken into consideration.
52

Determinants of adoption of genetically modified maize by smallholders in KwaZulu-Natal, South Africa

Manes, Rebecca January 1900 (has links)
Master of Science / Department of Agricultural Economics / Timothy Dalton / Previous research on small-scale farmers in KwaZulu-Natal, South Africa indicates that certain genetically modified maize seed types improve production efficiencies and increase net returns (Regier 2012). Yet despite the substantiated advantages, not all farmers have adopted genetically modified maize. The purpose of this research is to identify the determinants of adopting certain types of genetically modified maize over traditional or conventional hybrid maize for 184 small-holders in two villages in KwaZulu-Natal, South Africa. Previous adoption studies use socioeconomic characteristics of the farmer as well as farm-level production characteristics to determine the probability that a farmer will implement an improved agricultural technology. While many studies employ a binomial approach to adoption, this study tests the probability of adopting three different GM varieties—the insect resistant Bt maize, the herbicide tolerant Roundup Ready® maize, and the stacked trait BR maize. Furthermore, the model is enhanced by farmers’ open-ended explanations of their perceptions on genetically modified maize and of the major production constraints they face. Following results from previous adoption studies, this research tests three hypotheses in a three different model structures. The first hypothesis tests whether farmers are more likely to adopt if they have greater financial means to cover higher expected production costs. This is tested by variables measuring off-farm employment and expected production costs. The second hypothesis tests whether farmers with less labor availability are more likely to choose maize with the herbicide tolerant technology, either the Roundup Ready® or stacked BR maize, which reduce the need for weeding. The final hypothesis is whether there are differences in the determinants of adoption that differentiate GM adopters into three distinct categories. These hypotheses are tested in three model structures that test the binary probability of adopting GM maize over non-GM, the probabilities of adopting each maize variety separately, and the intensity of adoption. The first finding is that many non-adopters have greater access to income and are more likely to sell a portion of their yield than are many farmers who adopted, especially in comparison to those who plant RR maize. Also, BR farmers are more likely to report input expenses as a major constraint in their adoption decision. Results for the second hypothesis show that those who planted either RR or BR maize did in fact have less family labor available, used less total labor, and used a greater proportion of family to hired labor. Finally, there are differences in the determinants for geographic site, education, self-sufficiency in maize supply, number of family members working off-farm, and whether households planned to sell any of their maize yields. This indicates that adoption should be considered according to each genetically modified trait.
53

Nationalism and GMOs: the influence of nationally based ideals of nature on the public acceptance of genetically modified organisms: a comparative case study of the United States and the United Kingdom

Springsteel, Ian January 2002 (has links)
Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02
54

Detection of genetically modified foods (GMFs).

January 2001 (has links)
Wong Wai Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 175-192). / Abstracts in English and Chinese. / Declaration --- p.ii / Acknowledgements --- p.iii / Abstract --- p.iv / Abbreviation --- p.vi / Table of Contents --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Section I --- The Making of Genetically Modified Organisms --- p.2 / Chapter 1.1 --- Conventional breeding in agriculture --- p.2 / Chapter 1.2 --- What is genetic engineering? --- p.4 / Chapter 1.3 --- Plant transformation --- p.5 / Chapter 1.3.1 --- Agrobacterium-mediated --- p.6 / Chapter 1.3.2 --- Direct gene transfer --- p.8 / Chapter 1.3.2.1 --- Microparticle bombardment --- p.8 / Chapter 1.3.2.2 --- Protoplasts --- p.9 / Chapter 1.3.3 --- Gene silencing --- p.10 / Chapter 1.4 --- Examples of genetically modified crops --- p.13 / Chapter 1.5 --- Foreign genes commonly found in transgenic plants --- p.14 / Chapter Section II --- Benefits and Environmental Concern of GMOs --- p.17 / Chapter 2.1 --- Mechanism of GMO --- p.17 / Chapter 2.1.1 --- Herbicide tolerant crops --- p.18 / Chapter 2.1.2 --- Insect resistant crops --- p.19 / Chapter 2.1.3 --- Delayed ripening crops --- p.20 / Chapter 2.1.4 --- Virus resistant crops --- p.20 / Chapter 2.2 --- Benefits of GMOs --- p.21 / Chapter 2.3 --- Impact of GM foods to human health and the environment --- p.22 / Chapter 2.3.1 --- Human health --- p.22 / Chapter 2.3.1.1 --- GM potatoes --- p.23 / Chapter 2.3.1.2 --- CaMV risks? --- p.24 / Chapter 2.3.1.3 --- Food allergy --- p.25 / Chapter 2.3.2 --- Environmental concerns --- p.26 / Chapter 2.3.2.1 --- Horizontal gene transfer --- p.27 / Chapter 2.3.2.1.1 --- Selectable marker genes --- p.27 / Chapter 2.3.2.1.2 --- Herbicide resistant genes --- p.29 / Chapter 2.3.2.1.3 --- Insect resistant genes --- p.29 / Chapter 2.3.2.2 --- Ecology --- p.30 / Chapter 2.3.2.2.1 --- Monarch butterfly --- p.30 / Chapter Section III --- Future developments of GMO --- p.32 / Chapter 3.1 --- Designer Food and engineered plants --- p.32 / Chapter 3.1.1 --- Insect resistance --- p.33 / Chapter 3.1.2 --- Viral resistance --- p.33 / Chapter 3.1.3 --- Fungal resistance --- p.34 / Chapter 3.1.4 --- Nutritional quality --- p.34 / Chapter 3.1.5 --- Modifications of oil composition --- p.35 / Chapter 3.1.6 --- Medical applications --- p.37 / Chapter 3.1.7 --- Environmental applications --- p.40 / Chapter 3.1.7.1 --- Tolerance to high salinity and drought --- p.40 / Chapter 3.1.7.2 --- Tolerance to frost --- p.41 / Chapter 3.1.7.3 --- Bioremediation --- p.42 / Chapter 3.1.7.4 --- Biodegradable products --- p.43 / Chapter Section IV --- Regulation of GMO --- p.44 / Chapter 4.1 --- The question of labeling --- p.44 / Chapter 4.1.1 --- Moral and ethical issues --- p.44 / Chapter 4.1.2 --- Animal welfare --- p.45 / Chapter 4.2 --- International practice in GMO labeling --- p.46 / Chapter 4.2.1 --- United States of America --- p.46 / Chapter 4.2.2 --- Canada --- p.48 / Chapter 4.2.3 --- European Union --- p.49 / Chapter 4.2.4 --- Australia and New Zealand --- p.50 / Chapter 4.2.5 --- Japan --- p.51 / Chapter 4.2.6 --- Republic of Korea --- p.52 / Chapter 4.2.7 --- China --- p.53 / Chapter 4.2.8 --- Taiwan --- p.53 / Chapter 4.2.9 --- Hong Kong --- p.54 / Chapter Section V --- Uses of crops --- p.56 / Chapter 5.1 --- Uses of crops --- p.56 / Chapter 5.1.1 --- Soybean --- p.56 / Chapter 5.1.2 --- Corn --- p.57 / Chapter 5.1.3 --- Tomato --- p.58 / Chapter 5.1.4 --- Potato --- p.59 / Chapter 5.1.5 --- Rice --- p.60 / Chapter 5.1.6 --- Rapeseed --- p.61 / Chapter 5.1.7 --- Oil --- p.62 / Chapter 5.2 --- "Food additives, hormones and flavourings" --- p.63 / Chapter Chapter 2 --- Materials & Methods --- p.65 / Chapter 2.1 --- Materials --- p.66 / Chapter 2.1.1 --- Growth media & agar --- p.66 / Chapter 2.1.2 --- Reagents for agarose gel electrophoresis --- p.67 / Chapter 2.1.3 --- Reagents for preparation of competent cells --- p.67 / Chapter 2.1.4 --- Reagents for measurement of DNA concentration --- p.68 / Chapter 2.1.4.1 --- Measurement of DNA concentration by PicoGreen --- p.68 / Chapter 2.1.5 --- Reagents for Southern hybridization --- p.68 / Chapter 2.2 --- Methods --- p.70 / Chapter 2.2.1 --- Restriction endonuclease digestion --- p.70 / Chapter 2.2.2 --- Agarose gel electrophoresis of DNA --- p.70 / Chapter 2.2.3 --- DNA recovery from agarose gel --- p.71 / Chapter 2.2.3.1 --- QIAquick® gel extraction --- p.71 / Chapter 2.2.4 --- Ligation of purified DNA fragment into vector --- p.72 / Chapter 2.2.5 --- Transformation --- p.72 / Chapter 2.2.6 --- Rubidium chloride method for making competent cells --- p.12 / Chapter 2.2.7 --- Plasmid DNA preparation --- p.73 / Chapter 2.2.7.1 --- Concert Rapid Mini Prep --- p.73 / Chapter 2.2.7.2 --- QIAprep® Miniprep --- p.74 / Chapter 2.2.8 --- Extraction of plant genomic DNA --- p.75 / Chapter 2.2.8.1 --- Qiagen DNeasy´ёØ Plant Mini Kit --- p.75 / Chapter 2.2.9 --- Southern Hybridization --- p.75 / Chapter 2.2.9.1 --- Denaturation --- p.76 / Chapter 2.2.9.2 --- Blot transfer --- p.76 / Chapter 2.2.9.3 --- Pre-hybridization --- p.77 / Chapter 2.2.9.4 --- Synthesis of radiolabelled probe --- p.77 / Chapter 2.2.9.5 --- Hybridization of radiolabelled probe on filter --- p.77 / Chapter 2.2.9.6. --- Detection of hybridized probes --- p.78 / Chapter 2.2.10 --- Measurement of DNA concentration --- p.78 / Chapter 2.2.10.1 --- Determination of DNA on EtBr stained gel --- p.78 / Chapter 2.2.10.2 --- Determination of DNA by UV spectrophotometer --- p.78 / Chapter 2.2.10.3 --- Determination of DNA by PicoGreen --- p.79 / Chapter 2.2.11 --- DNA sequencing --- p.80 / Chapter 2.2.11.1 --- Automated sequencing by ABI Prism 377 --- p.80 / Chapter Chapter 3 --- PCR Diagnostics --- p.81 / Chapter 3.1 --- Applications of PCR to processed foods --- p.82 / Chapter 3.1.1 --- DNA quality --- p.82 / Chapter 3.1.2 --- PCR & Multiplex PCR --- p.83 / Chapter 3.1.3 --- Choice of primers --- p.84 / Chapter 3.1.4 --- Inhibitors --- p.84 / Chapter 3.2 --- Materials & Methods --- p.85 / Chapter 3.2.1 --- Selection of primers --- p.85 / Chapter 3.2.2 --- Amplification of target sequences --- p.86 / Chapter 3.2.3 --- Multiple amplification of target sequences --- p.87 / Chapter 3.3 --- Results --- p.88 / Chapter 3.4 --- Discussion --- p.93 / Chapter Chapter 4 --- Quality Control in GMO detection --- p.95 / Chapter 4.1 --- Standardization of pre- and post- PCR analysis --- p.96 / Chapter 4.1.1 --- General guidelines --- p.96 / Chapter 4.1.2 --- UV irradiation --- p.97 / Chapter 4.1.3 --- Inactivation protocols --- p.93 / Chapter 4.1.4 --- Positive and negative controls --- p.99 / Chapter 4.1.5 --- PCR verification --- p.99 / Chapter 4.1.6 --- Equipment decontamination --- p.100 / Chapter 4.2 --- Materials & Methods --- p.101 / Chapter 4.2.1 --- Selection of primers for external control --- p.101 / Chapter 4.2.2 --- Development of the external control --- p.101 / Chapter 4.2.3 --- Selection of primers for internal control --- p.103 / Chapter 4.3 --- Results --- p.104 / Chapter 4.4 --- Discussion --- p.107 / Chapter Chapter 5 --- DNA extraction from food samples --- p.110 / Chapter 5.1 --- Introduction --- p.111 / Chapter 5.2 --- Reagents and Buffers for DNA extraction from food samples --- p.112 / Chapter 5.2.1 --- Cetyltrimethylammonium bromide (CTAB) extraction method --- p.112 / Chapter 5.2.2 --- Organic-based extraction method --- p.113 / Chapter 5.2.3 --- Potassium acetate/sodium dodecyl sulphate precipitation method --- p.113 / Chapter 5.2.4 --- Hexane-based extraction method --- p.114 / Chapter 5.3 --- Weight and names of samples --- p.115 / Chapter 5.4 --- DNA extraction methods --- p.115 / Chapter 5.4.1 --- CTAB extraction method --- p.115 / Chapter 5.4.2 --- Qiagen DNeasy´ёØ plant mini kit --- p.116 / Chapter 5.4.3 --- Promega Wizard® genomic DNA purification --- p.116 / Chapter 5.4.4 --- Promega Wizard® Magnetic DNA purification system --- p.117 / Chapter 5.4.5 --- Promega Wizard® DNA Clean-Up system --- p.118 / Chapter 5.4.6 --- Qiagen QIAshreddrer´ёØ and QIAamp spin column --- p.119 / Chapter 5.4.7 --- Chelex-based extraction method --- p.119 / Chapter 5.4.8 --- Organic-based extraction method --- p.120 / Chapter 5.4.9 --- Nucleon PhytoPure extraction and purification method --- p.120 / Chapter 5.4.10 --- Potassium acetate/SDS precipitation method --- p.121 / Chapter 5.4.11 --- Hexane-based extraction method --- p.122 / Chapter 5.5 --- Results --- p.123 / Chapter 5.5.1 --- Comparison of eleven extraction methods --- p.123 / Chapter 5.5.2 --- Comparison of DNA extraction on selected methods --- p.125 / Chapter 5.6 --- Discussion --- p.132 / Chapter Chapter 6 --- Quantitative Analysis --- p.136 / Chapter 6.1 --- Introduction --- p.137 / Chapter 6.1.1 --- Chemistry of quantitative PCR --- p.138 / Chapter 6.1.2 --- PCR system --- p.140 / Chapter 6.2 --- Materials & Methods --- p.142 / Chapter 6.2.1 --- Design of primers and probes --- p.142 / Chapter 6.2.2 --- Methods --- p.145 / Chapter 6.3 --- Results --- p.146 / Chapter 6.3.1 --- Selection of primer/probe --- p.146 / Chapter 6.3.2 --- Primer optimization --- p.149 / Chapter 6.3.3 --- Quantitative analysis of real samples --- p.158 / Chapter 6.4 --- Discussion --- p.152 / Chapter Chapter 7 --- Conclusion --- p.168 / References --- p.175 / Appendix --- p.193
55

Impact of genetically modified (GM) food labeling system on food manufacturers in Hong Kong.

January 2002 (has links)
by Lam Lai Ming, Regina, Tang Oi Tai. / Thesis (M.B.A.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 65-66). / Questionnaire also in Chinese. / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / LIST OF TABLES --- p.vi / LIST OF FIGURES --- p.vii / ACKNOWLEDGEMENT --- p.ix / Chapter / Chapter I. --- INTRODUCTION --- p.1 / Genes and GM Food --- p.1 / Examples of GM Food Available in the Market --- p.2 / Potential Benefits and Risks of GM Food --- p.2 / Scientific Evidence for the Safety of GM Food --- p.5 / The International Scene of GM Food Labeling System --- p.6 / Pros and Cons of GM Food Labeling --- p.7 / Consumers' Perception and Acceptance of GM Food --- p.9 / Situation in Hong Kong --- p.11 / Hong Kong Public´ةs Concern --- p.13 / Chapter II. --- RESEARCH OBJECTIVES AND METHODOLOGY --- p.15 / Research Objectives --- p.15 / Methodology --- p.15 / Research Design --- p.15 / Questionnaire --- p.16 / Data Collection --- p.17 / Data Analysis Method --- p.17 / Chapter III. --- FINDINGS AND IMPLICATIONS --- p.19 / General Public's knowledge about / awareness of GM food --- p.19 / Consumers' Perception and Attitudes towards GM Food and Traditionally Produced Food --- p.22 / Quality --- p.25 / Nutritional Value --- p.27 / Price --- p.29 / Safety of consumption --- p.31 / Consumers' Purchasing Behavior --- p.34 / To evaluate consumers' opinions and reactions to the GM Food labeling system in Hong Kong --- p.40 / Profiles of the respondents --- p.43 / Limitations --- p.46 / Chapter IV. --- RECOMMENDATIONS --- p.48 / For Government --- p.48 / For GM Food Manufacturers --- p.50 / For Suppliers --- p.51 / APPENDIX --- p.53 / BIBLIOGRAPHY --- p.65
56

Public opinion and public engagement with genetically modified foods : a qualitative study

Moser, Celeste Laurana 01 January 2010 (has links)
The purpose of the current study was to understand public opinion formation by determining what factors influence opinion leaders in the organic food community to engage in the genetically modified food debate, and how opinion leaders describe American lay publics' engagement in the debate.
57

Protein Production in the Milk of Genetically Engineered Animals

Bates, Katherine M. 01 May 1998 (has links)
There are numerous proteins that have potential uses in commercial and scientific applications that are not utilized to their full potential. this is partly because it is not economically feasible to isolate some of these proteins from their natural sources or to produce them using bacterial fermentation methods. The purpose of this research was to target recombinant protein expression to the mammary glands of genetically engineered or transgenic animals. Foreign protein expression has been achieved in the mammary glands of rabbits, sheep, cows, and swine. By using a strong mammary gland promoter and signal peptide fused to the protein, it was hypothesized at the beginning of the study that the two proteins of this study would be secreted into the milk. To test this approach for protein production, expression vectors for two different plant proteins were made. The proteins targeted for expression were thaumatin and brazzein, proteins that have sweetener or flavor altering properties. The regulatory portion of the expression vector used exons and introns from the milk β-casein gene. Four and a half kilobases of the 5' region of the bovine β-casein gene was isolated, which contained the promoter sequence and other regulatory sequences for gene expression in mammary tissue. A size of 2.2 kilobases of the 3' region of the β-casein gene contained further regulatory sequences as well as a polyadenylation signal. The gene sequence for the protein was modified by using codons commonly used for casein and was generated using synthetic oligonucleotides. Additionally, the signal peptide from the alpha S-1 casein gene was used to transport the protein into the mammary milk vesicle. The DNA expression vectors were subsequently injected into murine and caprine embryos for the production of transgenic animals. Transgenic mice and a goat were identified that contained the thaumatin transgene. Preliminary analysis of mouse milk by capillary gel electrophloresis indicated the expression of thaumatin protein. This protein expression system is intended to utilize large dairy animals as bioreactors for efficient, non-toxic protein production with a view to being applied to different proteins as the technology advances.
58

Environmental biosafety of genetically engineered crops: Flax (Linum usitatissimum L.) as a model system

Jhala, Amitkumar 06 1900 (has links)
Flax (Linum usitatissimum L.) is considered as a model plant species for multipurpose uses with whole plant utilization for several purposes including industril, food, animal feed, fiber, nutraceutical, pharmaceutical, and bioproduct markets. Therefore, flax is in the process of genetic engineering to meet the market requirements. Prior to commercial release of genetically engineered (GE) flax, a risk assessment was conducted to determine intra- and inter-specific pollen-mediated gene flow and for quantifing and mitigating the adventitious presence (AP) of volunteer flax in canola (Brassica napus L.). The results of pollen-mediated gene flow study (crop-to-crop) suggest that about 1.85% outcrossing would occur in adjunct area, when two flax cultivars were grown in close proximity of 0.1 m apart. Some rare gene flow events were recorded maximum up to 35 m distance from the pollen source but at a very low frequency. The genus Linum has several wild and weedy species, distributed in many parts of the world. A meta-analysis was conducted to determine the potential for gene introgression from GE flax to wild relatives, the occurrence, the phylogeny of flax wild relatives and reported interspecific hybridization. The results demonstrated that cultivated flax has ability to hybridize and form viable F1 plants with at least nine species of Linum; however, none of these species have been reported to occur in Canada. Hybridization of flax with many other wild relatives has either not been studied or reported. However, based on the evidence of reported work, gene flow from GE flax to wild or weedy relatives may occur elsewhere depending on species distribution, sympatry, concurrent flowering, ploidy level and sexual compatibility. The results of the experiments to mitigate the adventitious presence of flax volunteers in canola suggest that combinations of pre-plant followed by post-emergence herbicides were most effective for reducing volunteer flax density and AP in glufosinate-resistant canola. Post-emergence application of imazamox+imazethapyr, however, was not effective for controlling volunteer flax in imidazolinone-resistant canola. Best management practices were developed to mitigate transgene movement from GE flax to ensure co-existance of GE, conventional and organic flax without market harm. / Plant Science
59

Development of a Tissue Engineered Pancreatic Substitute Based on Genetically Engineered Cells

Cheng, Shing-Yi 01 July 2005 (has links)
Genetically engineered cells have the potential to solve the cell availability problem in developing a pancreatic tissue substitute for the treatment of insulin-dependent diabetes (IDD). These cells can be beta-cells genetically engineered so that they can be grown in culture, such as the betaTC3 and betaTC tet mouse insulinomas developed by Efrat et al; or, they can be non-beta cells genetically engineered to secrete insulin constitutively or under transcriptional regulation. The aim of this work was to thoroughly characterize and improve the secretion dynamics of pancreatic substitutes based on genetically engineered cells. One issue involved with the continuous beta-cell lines is the remodeling of the cells inside an encapsulated cell system, which may affect the insulin secretion dynamics exhibited by the construct. To evaluate the effect of remodeling on the secretion properties of the construct, we used a single-pass perfusion system to characterize the insulin secretion dynamics of different alginate beads in response to step-ups and downs in glucose concentration. Results indicated that the secretion dynamics of beads indeed changed after long-term culture. On the other hand, data with a growth-regulated cell line, betaTC tet cells, showed that the secretion profile of beads can be retained if the cell growth is suppressed. A major concern associated with genetically engineered cells of non-beta origin is that they generally exhibit sub-optimal insulin secretion characteristics relative to normal pancreatic islets. Instead of relying on molecular tools such as manipulating gene elements, our approach was to introduce a glucose-responsive material acting as a control barrier for insulin release from a device containing constitutively secreting cells. Proof-of-concept experiments were performed with a disk-shaped prototype based on recombinant HepG2 hepatomas or C2C12 myoblasts, which constitutively secreted insulin, and concanavalin A (con A)-based glucose-responsive material as the control barrier. Results demonstrated that the a hybrid pancreatic substitute consisting of constitutively secreting cells and glucose-responsive material has the potential to provide a more physiologic regulation of insulin release than the cells by themselves or in an inert material.
60

Cultural impacts on public perceptions of agricultural biotechnology: comparison between South Korea and the United States

Nader, Richard Harrison 25 April 2007 (has links)
According to Millar (1996), the gulf between science and society is growing. Technologies are tools cultures develop to solve society's problems. The rapid dispersion of science and technology across cultural borders through trade, technology transfer and exchange, increasingly requires people in different cultures to make choices about accepting or rejecting artifacts of science and technology such as genetically modified (GM) foods, which originate primarily from the United States. These issues challenge policy makers and scientists to account for the affects of different cultural perspectives on controversial scientific issues. Given the controversy across cultures over acceptance or rejection of genetically modified (GM) foods, GM foods are an excellent example with which to begin to reveal how culture impacts public perceptions of the risk and benefits of science and technology in different societies. This research will: 1. Define public awareness and understanding of science, specifically GM foods; 2. Examine culture's impact on knowledge, including different cultural approaches to research; and 3. Compare recent findings of a bi-national public opinion survey on GM comparing in South Korea and the United States. The proposed research outlines two research questions: 1) How and in what ways do South Koreans and Americans differ in their opinions about GMOs? This question is important for gathering current points of contrast about how the two cultures may differ; and 2) What role does culture play on opinion formation about GM foods? Through grounded theory, the researcher will investigate how cultural differences help explain opinion on public perceptions of GM foods. Is it possible to identify common cultural factors that impact public perceptions of GM foods between South Koreans and Americans? The study will utilize both qualitative and quantitative methodologies. Higher education is a major producer of new science and technology. The study is significant for higher education administrators who must understand cultural factors impacting science internationally and globalization of the academic enterprise.

Page generated in 0.0566 seconds