Genetically modified food is a reality for many modern-day consumers around the world. With the introduction of GM food to the food market, consumers were faced with a number of new products and also familiar products containing new ingredients. The introduction of genetically modified food products to food markets around the world, led to a lot of controversy. In many cases consumer attitudes and perceptions of GM food products were revealed as fears, concern for, and avoidance of the new technology. Consumer attitudes, perceptions and acceptance towards the use of genetically modified foods or -food ingredients are currently highly relevant issues for role-player such as researchers, government, food companies, biotechnology companies, retailers and farmers all over the world.The importance of genetically modified food products in South Africa is increasing, even though the debate surrounding genetically modified food products lags behind many other (often more developed) parts of the world. Genetically modified white maize is among the agricultural crops approved for commercial production in South Africa. The production of genetically modified white maize in South Africa increased dramatically from its introduction in the 2001/2002-production season. White maize, especially in the form of super- and special maize meal, is an extremely important staple food source for consumers of all age groups in South Africa. The implication of the significant increase in the cultivation of genetically modified white maize is that the product is entering the South African food market at an increasing rate. In reality South African consumers are increasingly exposed to food products containing genetically modified white maize. This goes hand in hand with increasing consumer awareness regarding genetically modified food issues.The general objective of the dissertation is to develop an understanding of the perceptions, attitudes, acceptance and knowledge of South African urban consumers, regarding GM white maize as a staple food product within South Africa. The specific objectives are to identify trade-offs between selected attributes of maize meal and to determine the relative importance of selected GM characteristics within the trade-offs by means of a conjoint experiment, to construct market segments based on the outcomes of a conjoint experiment, to determine the effect of consumer perceptions on the sensory experience of white maize porridge and to determine the knowledge, perceptions and GM food acceptance of the different market segments.Quota sampling was applied to obtain a random sample of 80 urban white-maize consumers, based on the LSM (Living Standard Measures) market segmentation tool. The respondents participated in sensory evaluation of maize porridge. This was followed by a conjoint experiment designed around three selected product characteristic variables describing a 2.5kg packet of super white maize meal: “Brand variable”, “Genetic modification variable” and “Price variable”. Market segmentation was done through Ward’s hierarchical cluster analysis based on the conjoint results. The final phase of the experimental analysis involved the profiling of the identified clusters based on demographic variables, respondents’ knowledge of genetic modification and respondents perceptions, attitudes and acceptance towards genetically modified food.The limited sample size (80 respondents) could influence the ability of the results to reflect on the population of urban white maize consumers given the presence of GM food in the market. However, the experimental results should be seen in view of general trends in South Africa and available anecdotal evidence supporting the results of the study. The results of this study could go a long way in representing the results of a more representative sample of urban white maize consumers given the presence of GM food in the market.The cluster analysis revealed that the sample of urban, white maize consumers could be grouped into three meaningful and distinct market segments, based on their preferences for branded- versus non-branded white-grained maize meal, as well as their preferences for non-GM white maize meal versus GM white maize meal with various types of genetic manipulations. The “Anti-GM” segment (35% of the sample) is particularly negative towards GM food irrelevant of the type of genetic modification applied to the food. The “Pro-GM farmer sympathetic” segment (20% of the sample) is positive towards genetically modified food in cases where the farmer receives the benefit of the genetic modification. The “Pro-GM” segment (45% of the sample) is generally positive towards GM food, but especially when the consumer receives the benefit of the genetic modification. The results indicated that the differences among the cluster groups were more prominent than the differences among the LSM groups. Thus, the clusters were most effective to distinguish between sub-groups in the experimental sample.The results of the respondents’ knowledge of genetic modification indicated that there is some degree of confusion among respondents regarding the meaning of genetic modification, as well as discrepancies between perceived and actual knowledge levels of genetic modification. In general, the respondents’ knowledge of GM food is relatively low.A strong positive correlation was observed between the sample respondents’ exposure to GM food related terms and their perceived understanding of these issues, implying that the exposure caused the respondents to learn more about GM food related terms. The balanced GM food information presented to the respondents during the experimental procedure probably influenced their knowledge levels and opinions about GM food as the experiment evolved. Despite these observations the research methodology was still deemed as appropriate. The GM food knowledge gained by the respondents during the experiment could be seen as a simulation of situations where they could receive GM food information from external sources such as television, radio, magazines or newspapers. The cluster profiling revealed that urban white-grain maize consumers’ perceptions and attitudes towards GM food were the strongest distinguishing factors between the various market segments, especially the preferences of the various cluster groups for non-GM maize or maize that was genetically modified for consumer benefit or maize that was genetically modified for producer benefit. Demographic factors and GM knowledge aspects did not really contribute towards distinguishing between the clusters.The dissertation determined that there is a need for a better understanding of consumer perceptions, attitudes towards and acceptance of GM food products, which could enable producers and scientists to engage in more consumer driven product development and marketing activities. Consumer acceptance is the most critical factor for the success of GM food products within the South African food market place and could shape the future of the agricultural modern biotechnology industry and the agricultural sector in South Africa. / Dissertation (MSc (Agric) Agricultural Economics)--University of Pretoria, 2004. / Agricultural Economics, Extension and Rural Development / unrestricted

Indiana University-Purdue University Indianapolis (IUPUI) / Neurofibromatosis Type 1 (NF1) is a highly penetrant autosomal dominant genetic disorder where mutations in the tumor suppressor gene NF1 leads to decreased neurofibromin. The most debilitating manifestation is the presence of complex multilineage Schwann cell-derived plexiform neurofibromas (PN). Historically, little clinical success has been achieved targeting PN through surgery or chemotherapies. I performed an shRNA library screen of patient-derived Schwann cell lines to identify novel therapeutic targets to disrupt PN formation and progression. An shRNA library screen of human kinases and Rho-GTPases was performed in NF1-/- and paired NF1 competent immortalized Schwann cell lines. Following sequencing, candidates were identified. We previously developed a novel mouse model of NF1 wherein a neural crest specific Postncre targeted loxp-flanked Nf1 that replicated the PN found in patients. Additional cohorts of mice were generated with biallelic deletion of Rac1 (Nf1f/fRac1f/f Postn-Cre+; DKO ). Mice were aged for 9 months and peripheral nerves were harvested and fixed in formalin. Peripheral nerve size was measured and tumors were identified through blinded analysis of hematoxylin and eosin and Masson’s Trichrome (collagen) stained slides. Rho family members, including RAC1, were identified as candidates through an shRNA library screen. Genetic disruption of Rac1 in the Schwann cell lineage resulted in the prevention of tumor formation in DKO mice, as observed by peripheral nerve size and histological analysis. I observed an average of 14.8 +/- 2.65 tumors per mouse in the Nf1f/f Postnviii Cre+ cohort compared to 0 tumors in the DKO (p<0.0001). Following an shRNA library screen, RAC1 was identified as a candidate to modulate PN formation. Biallelic deletion of Rac1 in vivo prevented PN formation. I demonstrate that a candidate identified in an shRNA library screen can translate to an biological effect in a mouse model of PN.

Genetically modified (GM) food could be a solution to secure the world’s food supply, whichis in jeopardy due to the ongoing climate crisis. Thus, it is of great importance that consumerswould be willing to consume this type of food. To examine which factors influence consumerbehavior toward GM food, an extension of the theory of planned behavior was applied anddecisive factors were evaluated. The derived hypotheses and the respective influencing factorsare based on the research of Prati et al. (2012) as well as the questions that were used in theonline questionnaire. Through this online questionnaire with 117 participants, the hypotheseswere tested and factors that influence the intention of consumers to consume geneticallymodified food were identified. It was found that the following factors are relevant: Perceivedbenefits, Subjective norm, and Attitude. Of these, the factor Perceived benefits has the greatestinfluence on intention. Factors that do not play a role are Perceived control and, contrary toexpectations, Perceived risks.Another factor that was tested beyond the scope of the theory was the relevance of thenationality of participants on their intention to consume genetically modified food. However,it was found that nationality does not influence the intention. Concluding, the findings revealthat consumers can be especially influenced by their perception of benefits.

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BACKGROUND: Aberrant MET receptor tyrosine kinase (RTK) activation leads to invasive tumor growth in different types of cancer. Overexpression of MET and its ligand hepatocyte growth factor (HGF) occurs more frequently in glioblastoma (GBM) than in low-grade gliomas. Although we have shown previously that HGF-autocrine activation predicts sensitivity to MET tyrosine kinase inhibitors (TKIs) in GBM, whether it initiates tumorigenesis remains elusive. METHODS: Using a well-established Sleeping Beauty (SB) transposon strategy, we injected human and cDNA together with a short hairpin siRNA against (SB-hHgf.Met.ShP53) into the lateral ventricle of neonatal mice to induce spontaneous glioma initiation and characterized the tumors with H&E and immunohistochemistry analysis. Glioma sphere cells also were isolated for measuring the sensitivity to specific MET TKIs. RESULTS: Mixed injection of SB-hHgf.Met.ShP53 plasmids induced de novo glioma formation with invasive tumor growth accompanied by HGF and MET overexpression. While glioma stem cells (GSCs) are considered as the tumor-initiating cells in GBM, both SB-hHgf.Met.ShP53 tumor sections and glioma spheres harvested from these tumors expressed GSC markers nestin, GFAP, and Sox 2. Moreover, specific MET TKIs significantly inhibited tumor spheres' proliferation and MET/MAPK/AKT signaling. CONCLUSIONS: Overexpression of the HGF/MET axis along with p53 attenuation may transform neural stem cells into GSCs, resulting in GBM formation in mice. These tumors are primarily driven by the MET RTK pathway activation and are sensitive to MET TKIs. The SB-hHgf.Met.ShP53 spontaneous mouse glioma model provides a useful tool for studying GBM tumor biology and MET-targeting therapeutics.

Lignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plantbased production of these enzymes on large scale offers a cost effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. β- mannanase catalyzes endo-hydrolysis of the mannan backbone, a major constituent of woody biomass. In this study, man1 gene encoding β-mannanase was isolated from Trichoderma reesei and expressed via the chloroplast genome. PCR and Southern hybridization analysis confirmed the site-specific transgene integration into the tobacco chloroplast genomes and homoplasmy. Transplastomic plants were fertile and set viable seeds. Germination of seeds showed inheritance of transgenes into the progeny without Mendelian segregation. Expression of the endo-β-mannanase gene for the first time in plants facilitated its characterization for use in enhanced lignocellulosic biomass hydrolysis. Gel diffusion assay for endo-β-mannanase showed the zone of clearance confirming functionality of chloroplast-derived mannanase. Endo-β-mannanase expression levels reached up to 25 units per gram of leaf (fresh weight). Chloroplastderived mannanase had higher temperature stability (40 °C to 70 °C) and wider pH optima (pH 3.0 to 7.0) than E.coli enzyme extracts. Plant crude extracts showed 6-7 fold iv higher enzyme activity than E.coli extracts due to the formation of disulfide bonds in chloroplasts, thereby facilitating their direct utilization in enzyme cocktails without any purification. Chloroplast-derived mannanase when added to the enzyme cocktail containing a combination of different enzymes yielded 20% more glucose equivalents from pinewood than the cocktail without mannanase. Our results demonstrate that chloroplast-derived mannanase is an important component of enzymatic cocktail for woody biomass hydrolysis and should provide a cost-effective solution for its diverse applications in the paper, oil, pharmaceutical, coffee and detergent industries.

In the past fifty years there has been an incredible amount of change made to the agrarian system of the United States. New discoveries in the realm of biotechnology led to the adoption of genetically modified organisms (GMOs) in agriculture, and transformed the industry. Due to regulatory policies set during the nineteen-eighties this technology was able to benefit from widespread commercialization. Today, we see the effects of this approach and are entering into a highly volatile political climate in regard to GMOs. This paper aims to provide an analysis of the regulatory system in place and the discrepancies that exist in US policy. The factors evaluated through this thesis include the current US regulatory approach, advancements in biotechnology, and a comparative perspective on US and EU systems. In each of these reviews it is also relevant to mention consumer opinion on GMOs and the role of interest groups. It is important for every American consumer to understand the politics and technology behind their meals. Through the analysis of recent judicial decisions and the enactment of new laws this thesis explains how the use of GMOs in agriculture is causing an unprecedented change to the political structures in place.

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<p> Exercise intensity is one of the major factors determining the utilization of carbohydrates (CHO) and lipids in mammalian skeletal muscle. Using indirect calorimetry, we determined maximal oxygen uptake (VO2max) and whole-body rates of CHO and lipid oxidation in rats selectively bred for high and low running capacity (HCR's and LCR's) during exercise at 50, 60, 70 and 80%VO2max. Previous studies have revealed a pattern of selection where mammals with different aerobic capacities use the same proportions of lipids and CHO when exercising at the same relative exercise intensity and as intensity increases, CHO use increases and lipid use decreases. The present results showed that the HCR's had a VO2max and distance run to exhaustion that was 1.3 and 4.0 times greater than the LCR's respectively. Also, both groups of rats followed the pattern of fuel selection seen in previous studies where the same proportions (in%) of lipids and CHO are used at the same relative exercise intensity. On an absolute scale, the HCR's used more lipids and CHO than the LCR's at all exercise intensities but the results were not always statistically significant. We also determined the exercise intensity that elicited the greatest lipid use to be 60% VO2max in both groups.</p> <p> In order to explain these patterns of fuel selection, metabolic indicators, metabolites and enzymes, in skeletal muscle were measured at rest and post exercise for one hour at 60%VO2max. Specifically, ATP and phosphocreatine (PCr) metabolite concentrations were determined in the medial and lateral gastrocnemius, extensor digitorum longus (EDL), tibialis anterior (TA), and soleus muscle. The medial gastrocnemius and soleus were analyzed (pre and post exercise samples were combined) for their oxidative and glycolytic enzyme activity by measuring citrate synthase (CS), cytochrome oxidase (COX), β-hydroxyacyl CoA dehydrogenase (HOAD), and lactate dehydrogenase (LDH) . PCr and ATP concentrations did not change pre and post exercise and between the HCR's and LCR's except for the EDL where there was a significant decrease (P<0.05) in both metabolites after exercise in both groups of rats. For the enzyme measurements, CS and COX activities were higher (P<0.05) in the HCR's for the soleus and HOAD activities were also higher in the HCR's medial gastrocnemius compared to the LCR's. We concluded that the HCR's have a greater oxidative capacity as shown by their greater aerobic and endurance capacity (VO2max and distance to exhaustion), their ability to oxidize a greater absolute amount of lipids and CHO's at the same relative exercise intensity, and their higher activities of oxidative enzymes in the soleus (CS and COX) and medial gastrocnemius (HOAD). Future research into the mechanisms involved in explaining these patterns of fuel selection may include examining fatty acid transport proteins, fatty acid and CHO availability, fiber types, and catecholamines.</p> / Thesis / Master of Science (MSc)

O melhoramento genético clássico de sementes milho (Zea mays L.) permitiu desenvolver inúmeras variedades, incluindo o milho com qualidade proteica melhorada (Quality Protein Maize, QPM), que visava aumentar os teores proteicos e as propriedades nutricionais. Por outro lado, novas variedades comerciais foram obtidas por vegetais geneticamente modificados (GM), com foco em parâmetros agronômicos. Em ambos os casos, a segurança dessas variedades para uso como alimento é uma das principais preocupações dos desenvolvedores e dos órgãos de regulamentação. A Equivalência Substancial é a base do sistema de avaliação da segurança de culturas geneticamente modificadas, no entanto alterações na expressão de proteínas não são devidamente analisadas e esclarecidas. As abordagens proteômicas complementam as técnicas de avaliação de biossegurança para alimentos GM, bem como permitem investigar possíveis efeitos indesejáveis derivados do melhoramento clássico. Os objetivos do presente estudo foram caracterizar e comparar os perfis proteicos de variedades de milhos convencionais melhorados (QPM) e geneticamente modificados (GMs), contra suas respectivas linhas convencionais utilizando técnicas proteômicas como eletroforese bidimensional (2-DE) e bottom up shotgun (gel-free). Num primeiro estudo, foram utilizadas três amostras de milho, sendo duas variedades convencionais com QPM (QP1 e QP2) e uma variedade convencional normal (CN). No segundo estudo, foram analisadas duas cultivares de milho GM (GM1 e GM2) e seus respectivos convencionais genitores (CG1 e CG2). As composições químicas de todas as amostras também foram avaliadas quanto a Equivalência Substancial. O extrato bruto proteico foi submetido à análise de eletroforese unidimensional (1-DE), bidimensional (2-DE) e bottom up shotgun (gel-free). As imagens dos mapas proteicos foram analisadas pelo software Image Master 2D Platinum 7.0 (GE). Os spots diferencialmente expressos e selecionados foram sequenciados por MS. Pela composição química das principais frações das amostras de milho foi possível identificar a equivalência substancial entre as amostras convencionais e GMs, bem como QPMs e sua convencional dentro das faixas de variabilidade esperadas da espécie. Nos géis 1-DE foram observadas bandas proteicas com perfis similares entre os grupos de amostras avaliadas para ambos estudos. Nas imagens dos géis 2-DE não houveram alterações extremas entre as amostras de milhos GMs e seus respectivos convencionais genitores (CGs), mas apenas diferenças na intensidade dos spots proteicos. As variedades QPMs e CN apresentaram diferenças devido à distribuição dos spots. Os mapas proteicos das amostras CG1 x GM1 e CG2 x GM2 apresentaram maior semelhança com porcentagens de matchings superiores a 70 %, enquanto as porcentagens de matchings entre variedades diferentes (QPMs e CN) foram menores. No total foram identificadas 219 proteínas das amostras CGs x GMs e QPMs x CN, classificadas quanto aos seus processos biológicos e função molecular. Em conclusão, foram encontradas diferenças entre os cultivares GMs e CGs, indicando uma variação normal entre variedades de milho, que não comprometem a segurança alimentar das amostras estudadas. Quanto às amostras com QPM e CN as diferenças encontradas são devido à sua distância nas linhagens ou germoplasma. / The classic genetic breeding of corn seeds (Zea mays) has enabled the development of many varieties, including corn with improved protein quality (Quality Protein Maize, QPM), which aimed to increase protein levels and nutritional properties. On the other hand, new commercial varieties have been obtained out of genetically modified (GM) vegetables, with a focus in agronomic parameters. In both cases, the safety of these varieties for food use is one of the main concerns for the developers and for the regulatory agencies. Substantial Equivalence is the basis of the safety evaluation system for genetically modified crops, however, alterations in the protein expressions are not been properly analyzed and clarified. The protein approaches complement the techniques of biosafety evaluation for GM foods, as well as allow for possible undesirable effects derived from classic improvement to be investigated. The goals of the current studies were to characterize and compare the protein profiles of the different varieties of conventionally improved (QPM) and genetically modified (GM) corn, against their respective conventional lines using proteomic techniques, such as, two-dimensional electrophoresis (2-DE), bottom up shotgun (gel-free) and masses spectrometry (MS). In a first instance of the study, three samples of corn were used, two of conventional varieties with QPM (QP1 and QP2) and one conventional normal variety (CN). In a second instance of the study, two cultures of GM corn (GM1 and GM2) were analyzed and their respective conventional genitors (CG1 and CG2). The chemical compositions of all the samples were also evaluated for their Substantial Equivalence. The protein raw extract was submitted to analysis of one-dimensional (1-DE), two-dimensional (2-DE) electrophoresis, and bottom up shotgun (gel-free). The protein image maps were analyzed by the Image Master 2D Platinum 7.0 (GE) software. The spots which were expressed and selected differentially were sequenced by MS. By the chemical composition of the main fractions of the samples of corn, it was possible to identify the substantial equivalence between the conventional samples and GMs, likewise with OPMs and their conventional in the ranges of variability which were expected for the species. On the 1-DE gel, it was observed protein bands with similar profiles amongst the groups of evaluated samples for both studies. In the images of the 2-DE gel, there were no alterations between the GM corn and their respective conventional genitors (CGs), but only differences in intensity of the protein spots. The OPM and CN varieties presented differences due to the distribution of the spots. The protein maps of samples CG1 vs. GM1 and CG2 vs. GM2 presented greater similarities with the percentages of matchings superior to 70%, while the percentage of matchings among different varieties (QPMs and CN) were smaller. In total, there were 219 proteins identified in the samples CGs vs. GMs and QPMs vs. CN, classified by the biologic processes and molecular function. In conclusion, there were found differences between the cultures of GMs and CGs, indicating a normal variation among the corn varieties, which do not affect the food security of the studied samples. As per the samples with QPM and CN, the differences found were due to the line distances or germplasm.