Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology and Food Technology, Durban University of Technology, 2007 iv, 75 leaves / The development of transgenic plants resulted in the need to utilize the various molecular methods (e.g., ELISA, real - time PCR etc.) for the detection or analysis of the presence or absence of a specific trait in a particular plant (Bt in this study). The overall aim of this study was to optimize a half – seed extraction technique as part of a laboratory protocol for transgenic maize plants and to explore the possibility of using the following molecular techniques: horizontal isoelectric focusing, real - time PCR and ELISA, as methods for detection of the Bt trait for incorporation into the half – seed extraction protocol.

Consider this: South Africa recently became the first country in the world to commercially release genetically engineered maize for human consumption. In contrast to the cautionary approach adopted by other African countries, South Africa has one of the fastest growth rates in genetically engineered crop cultivation worldwide, almost doubling the number of hectares of the country now planted with genetically engineered crops since 2001. Owing to the genetic engineering revolution in our food, it is no wonder that people are becoming more concerned about the food on their plates than ever before. It is essential that people consuming genetically engineered food become aware of who is benefiting and who is not benefiting from the biotechnological industry, by understanding the risks to health, the environment and the economy. If the food that consumers purchase is genetically engineered, consumers should have the right to know and make that choice to either purchase or avoid genetically engineered food. This topic is pertinent in South Africa, as the government has clearly decided that genetically engineered food is part of our future and, to date, the labelling of GE food is not mandatory. / Thesis (LL.M.)-University of Natal, Durban, 2003.

Zugl.: Stuttgart, Univ., Diss., 2007 / Includes bibliographical references (p. 287-304).

Thesis (Ph. D.)--American University, 2002. / Includes bibliographical references (leaves 544-587).

There are many technologies being developed for crop breeding. Two interesting technologies are genetic modification and genetic editing. Competitive pressures and changing consumer preferences are forcing organizations to invest heavily in these two technologies. Organizations must decide which traits they want to target and must commit significant time a money to the project. Traditionally, firms would decide which project to embark on if the project is net present value positive. Throughout the research and development process managers have flexibility to abandon the project once new information is received. That flexibility has value and real option analysis must be performed to value that flexibility. Once the value of a GM and GE project is determined, how might an organization decide which project to do? The concept of minimum required acreage (MRA) is developed in this study, allowing organizations to compare GM and GE technologies and decide which project to invest it.

by Chan, Yuk Wah. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 166-175). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.iii / ABSTRACT --- p.v / 摘要 --- p.vii / LIST OF CONTENTS --- p.viii / LIST OF FIGURES --- p.xiv / LIST OF TABLES --- p.xvii / LIST OF ABBREVIATIONS --- p.xviii / Chapter CHAPTER 1. --- GENERAL INTRODUCTION --- p.1 / Chapter CHAPTER 2. --- LITERATURE REVIEW --- p.5 / Chapter 2.1 --- Vitamin A --- p.5 / Chapter 2.1.1 --- General and properties --- p.5 / Chapter 2.1.2 --- Biological importance of vitamin A --- p.6 / Chapter 2.1.3 --- Deficiency symptoms --- p.9 / Chapter 2.1.4 --- Dietary source of vitamin A --- p.10 / Chapter 2.1.5 --- Metabolism of dietary vitamin A and provitamin A in human --- p.12 / Chapter 2.1.5.1 --- Digestion and absorption --- p.12 / Chapter 2.1.5.2 --- Bioconversion --- p.12 / Chapter 2.1.5.2.1 --- "β, β-carotene-15,15'-monooxygenase (BCMO)" --- p.13 / Chapter 2.1.5.3 --- "Transport, uptake and storage" --- p.15 / Chapter 2.2 --- Vitamin A deficiency (VAD) --- p.19 / Chapter 2.2.1 --- Present situation --- p.19 / Chapter 2.2.2 --- Global efforts in dealing with VAD --- p.21 / Chapter 2.2.2.1 --- Vitamin A supplementation --- p.21 / Chapter 2.2.2.2 --- Food fortification --- p.22 / Chapter 2.2.2.3 --- Biofortification --- p.23 / Chapter 2.2.2.3.1 --- Conventional selective breeding --- p.23 / Chapter 2.2.2.3.2 --- Biosynthesis of provitamin A in plants --- p.25 / Chapter 2.2.2.3.3 --- Carotenoids enhancement in major plants and food crops --- p.31 / Chapter 2.3 --- Inherent problems of the present carotenoid enhancement --- p.34 / Chapter 2.3.1 --- Recommended Dietary Amount of vitamin A --- p.34 / Chapter 2.3.2 --- Factors affecting the bioefficacy of provitamin A in human body --- p.35 / Chapter 2.3.2.1 --- Bioavailability --- p.36 / Chapter 2.3.2.2 --- Bioconvertibility --- p.38 / Chapter 2.3.2.3 --- Health and nutrition status --- p.39 / Chapter 2.4 --- Previous study in our lab --- p.41 / Chapter 2.4.1 --- Overexpression of rice PSY1 --- p.41 / Chapter 2.4.2 --- Introduction of carotenoid genes and BCMOs into rice --- p.44 / Chapter 2.5 --- Overview of the project --- p.50 / Chapter CHAPTER 3. --- MATERIALS AND METHODS --- p.52 / Chapter 3.1 --- Chemicals --- p.52 / Chapter 3.2 --- Bacterial strains in regular cloning --- p.52 / Chapter 3.3 --- BCMO genes and carotenogenic genes --- p.53 / Chapter 3.4 --- Expression of BCMOs in bacterial system --- p.54 / Chapter 3.4.1 --- lac promoter system --- p.54 / Chapter 3.4.2 --- pBAD-TOPO® system --- p.56 / Chapter 3.5 --- Construction of gene cassettes for plant transformation --- p.58 / Chapter 3.5.1 --- Gene cassettes for carrot transformation --- p.58 / Chapter 3.5.1.1 --- Construction of gene cassettes for chicken or zebrafish bcmo driven by CaMV 35S promoter --- p.58 / Chapter 3.5.1.2 --- Construction of gene cassettes for chicken or zebrafish bcmo driven by lycopene-β-cyclase promoter --- p.63 / Chapter 3.5.2 --- Gene cassettes for Arabidopsis transformation --- p.67 / Chapter 3.5.2.1 --- Construction of gene cassettes expressing Dcpsy --- p.67 / Chapter 3.5.2.2 --- Construction of gene cassettes expressing mbcmos --- p.69 / Chapter 3.5.3 --- Gene cassettes for Rice transformation --- p.72 / Chapter 3.5.3.1 --- Construction of gene cassettes expressing mbcmos --- p.72 / Chapter 3.5.3.2 --- Construction of gene cassettes expressing Ospsyl and mbcmos --- p.74 / Chapter 3.5.4 --- Confirmation of sequence fidelity --- p.76 / Chapter 3.6 --- Carrot transformation --- p.76 / Chapter 3.6.1 --- Plant materials --- p.76 / Chapter 3.6.2 --- Preparation of Agrobacterium --- p.76 / Chapter 3.6.3 --- Agrobacterium mediated transformation --- p.77 / Chapter 3.6.3.1 --- Seed germination --- p.78 / Chapter 3.6.3.2 --- Co-cultivation with hypocotyls --- p.78 / Chapter 3.6.3.3 --- Callus induction and selection --- p.78 / Chapter 3.6.3.4 --- Liquid cell culture preparation and embryogenesis induction --- p.79 / Chapter 3.6.3.5 --- Regeneration --- p.80 / Chapter 3.7 --- Arabidopsis Transformation --- p.80 / Chapter 3.7.1 --- Plant materials --- p.80 / Chapter 3.7.2 --- Preparation of Agrobacterium --- p.81 / Chapter 3.7.3 --- Agrobacterium mediated transformation --- p.81 / Chapter 3.7.3.1 --- Co-cultivation --- p.81 / Chapter 3.7.3.2 --- Selection --- p.82 / Chapter 3.8 --- Rice transformation --- p.83 / Chapter 3.8.1 --- Plant materials --- p.83 / Chapter 3.8.2 --- Preparation of Agrobacterium --- p.83 / Chapter 3.8.3 --- Agrobacterium mediated transformation --- p.83 / Chapter 3.8.3.1 --- Callus induction from mature rice seeds --- p.84 / Chapter 3.8.3.2 --- Co-cultivation and selection --- p.84 / Chapter 3.9 --- Detection of transgene expression --- p.86 / Chapter 3.9.1 --- Detection at DNA level --- p.86 / Chapter 3.9.1.1 --- Genomic DNA extraction --- p.86 / Chapter 3.9.1.2 --- PCR screening --- p.86 / Chapter 3.9.1.3 --- Synthesis of DIG-labelled DNA probes --- p.86 / Chapter 3.9.1.4 --- Southern blot analysis --- p.87 / Chapter 3.9.2 --- Detection at RNA level --- p.88 / Chapter 3.9.2.1 --- Total RNA extraction --- p.88 / Chapter 3.9.2.2 --- Northern blot analysis --- p.89 / Chapter 3.9.2.3 --- RT-PCR --- p.89 / Chapter 3.9.3 --- Detection at protein level --- p.89 / Chapter 3.9.3.1 --- Antibody production --- p.89 / Chapter 3.9.3.1.1 --- B.CMO protein induction in pET30a-bacterial system --- p.90 / Chapter 3.9.3.1.2 --- Immunization of rabbit and serum collection --- p.93 / Chapter 3.9.3.2 --- Protein extraction and Tricine SDS-PAGE --- p.93 / Chapter 3.9.3.3 --- Western blot analysis --- p.94 / Chapter 3.9.4 --- Detection at final product level --- p.95 / Chapter 3.9.4.1 --- UPLC analysis --- p.95 / Chapter 3.9.4.1.1 --- Extraction of total carotenoids and retinoids --- p.95 / Chapter 3.9.4.1.2 --- UPLC identification --- p.96 / Chapter CHAPTER 4. --- RESULTS --- p.97 / Chapter 4.1 --- Modified bcmo genes --- p.97 / Chapter 4.2 --- Expression of BCMOs in bacterial system --- p.102 / Chapter 4.2.1 --- lac promoter system --- p.104 / Chapter 4.2.2 --- pBAD-TOPO® system --- p.106 / Chapter 4.2.3 --- UPLC detection --- p.108 / Chapter 4.3 --- Carrot transformation --- p.110 / Chapter 4.3.1 --- Construction of gene cassettes for carrot transformation --- p.110 / Chapter 4.3.2 --- Seed germination and co-cultivation --- p.112 / Chapter 4.3.3 --- Callus induction and selection --- p.113 / Chapter 4.3.4 --- Embryogenesis induction and regeneration --- p.113 / Chapter 4.3.5 --- Callus induction in the dark --- p.115 / Chapter 4.3.6 --- Detection of native BCMO --- p.116 / Chapter 4.3.6.1 --- Genomic PCR screening of 35Spro - zebcmo transgenic lines --- p.116 / Chapter 4.3.6.2 --- Southern blot analysis of 35Spro - zebcmo transgenic lines --- p.117 / Chapter 4.3.6.3 --- RT-PCR of 35Spro - zebcmo transgenic lines --- p.118 / Chapter 4.3.6.4 --- Detection at protein level --- p.119 / Chapter 4.3.6.4.1 --- Antibody production --- p.119 / Chapter 4.3.6.5 --- Western blot analysis of 35Spro - zebcmo transgenic lines --- p.123 / Chapter 4.3.6.6 --- Genomic PCR screening of later transgenic lines --- p.123 / Chapter 4.3.6.7 --- Western blot analysis of later transgenic lines --- p.125 / Chapter 4.3.6.8 --- UPLC analysis of later transgenic lines --- p.127 / Chapter 4.3.7 --- Detection of modified BCMO --- p.130 / Chapter 4.3.7.1 --- Genomic PCR screening --- p.130 / Chapter 4.3.7.2 --- Northern blot analysis --- p.132 / Chapter 4.3.7.3 --- Western blot analysis --- p.134 / Chapter 4.3.8 --- UPLC analysis --- p.136 / Chapter 4.4 --- Arabidopsis transformation --- p.138 / Chapter 4.4.1 --- Construction of gene cassettes for Arabidopsis transformation --- p.138 / Chapter 4.4.2 --- Selection --- p.139 / Chapter 4.4.3 --- Genmoic PCR screening of Arabidopsis transformants --- p.140 / Chapter 4.4.4 --- UPLC analysis for Arabidopsis transformants --- p.142 / Chapter 4.5 --- Rice transformation --- p.144 / Chapter 4.5.1 --- Construction of gene cassettes for rice transformation --- p.144 / Chapter 4.5.2 --- "Callus induction from mature rice seeds, co-cultivation and selection" --- p.146 / Chapter 4.5.3 --- Genomic PCR screening of Rice transformants --- p.147 / Chapter 4.5.4 --- UPLC analysis of rice transformants --- p.149 / Chapter CHAPTER 5. --- DISCUSSION --- p.151 / Chapter 5.1 --- Bacterial expression of BCMO --- p.151 / Chapter 5.2 --- Analysis of BCMO in plants --- p.153 / Chapter 5.2.1 --- Carrot --- p.154 / Chapter 5.2.1.1 --- Expression of BCMO in carrot transformants --- p.154 / Chapter 5.2.1.2 --- UPLC analysis of carrot transformants --- p.155 / Chapter 5.2.2 --- Arabidopsis --- p.156 / Chapter 5.2.3 --- Rice --- p.158 / Chapter 5.3 --- Proposed explanation for the failure of retinal production --- p.159 / Chapter 5.3.1 --- Retinal sequestration --- p.160 / Chapter 5.3.2 --- Localization of BCMO --- p.161 / Chapter 5.4 --- Future prospects --- p.163 / Chapter CHAPTER 6. --- CONCLUSIONS --- p.165 / REFERENCES --- p.166 / APPENDICES --- p.176

Abstract not available

Thesis (MSc)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The cellular expression of the enzymes implicated in regulating sucrose metabolism and accumulation in sugarcane is poorly understood. The present study was therefore aimed at the development of an in situ hybridisation (ISH) technique to study differential gene expression among the various cell types of the sugarcane culm. This technique in conjunction with northern and western blotting was then used to determine the sites of cellular and tissue specific expression of the cytosolic enzymes, UDP-Glc dehydrogenase, pyrophosphate dependent phosphofructokinase and UDP-Glc pyrophosphorylase, involved in sucrose metabolism. This study revealed that the determination of the influencing parameters associated with the development of an ISH protocol was essential for the successful detection of the endogenous RNA sequences in sugarcane internodal tissues. The parameters that were investigated included the type of embedding medium, duration of fixation period, pre-treatment procedures and hybridisation temperature. It further revealed that fresh internodal tissue sections, fixed for a period of 24 h and thereafter exposed to pre-treatment and hybridisation, facilitated the analysis of cytological gene expression at all stages of sugarcane development. The second part of this study revealed very localised transcript expression for UDP-Glc DH, PFP and UGPase in the different internodal tissue and cell types. The UDP-Glc DH and UGPase transcripts were localised to the phloem elements, whilst xylem tissue only expressed the UDP-Glc DH transcript. Transcripts of UDP-Glc DH, PFP and UGPase were all expressed in the parenchyma cells that were associated with the vascular bundles and the stem storage compartment, suggesting that the parenchyma cells distributed throughout the stem in the different tissue types complement each other in function for the purposes of phloem loading, unloading and assimilate transport processes. Complimentary northern and western hybridisations demonstrated that internode 7 represents a shift in the sink from utilisation to storage. This is evident by the observed decline in both the relative transcript and protein abundances of UDP-Glc DH, PFP and UGPase at this stage of development. The relative mRNA and protein abundances for the three enzymes showed a similar trend. Higher levels of the gene transcripts and translated products were observed in the younger sucrose importing tissues, than in the older sucrose accumulating internodes. At a cellular level, it was found that the sites of cellular UDP-Glc DH, PFP and UGPase expression differed marginally. Whilst UDP-Glc DH was expressed in the phloem, xylem and parenchyma cells of the vascular complex and in storage parenchyma cells, PFP was expressed exclusively in parenchyma cells that were associated with the vascular bundles and those serving a storage function in the stem pith and UGPase was found to be localised in the phloem and parenchyma of the vascular bundles and the storage parenchyma cells. Such findings have demonstrated an increase in resolution with which gene expression can be examined at a cellular level. Hence, the results from this study have demonstrated that the knowledge of metabolic compartmentation between different tissue and cell types is a requisite to understanding the function(s) of individual enzymes within complex structures such as the sugarcane culm. / AFRIKAANSE OPSOMMING: Die sellulêre lokalisering van die ensieme wat geïmpliseer word in die regulering van sukrose metabolisme is onbekend. Met dit in gedagte, was hierdie studie gefokus op die ontwikkeling van 'n in situ hibridisasie (ISH) tegniek om differensiële geenuitdrukking in die verskillende seltipes van die suikerrietstingel te ondersoek. Hierdie tegniek, tesame met RNA-en proteïen gel blots, is volgens aangewend om die areas van sellulêre-en weefselspesifieke uitdrukking van die sitosoliese ensieme UDP-glukose dehydrogenase, pirofosfaat-afhanklike fosfofruktokinase en UDP-glukose pirofosforilase, wat almal betrokke is by sukrosemetabolisme, te bepaal. Dit het duidelik geword gedurende die studie dat die bepaling van die optimale parameters van die ISH protokol vir suikerriet van deurslaggewende belang sou wees vir die opsporing van endogene RNA volgordes. Die parameters wat ondersoek is het ingesluit die tipe inbeddingsmedium, die tydsduur van fiksering, vooratbehandelings- en hibridisasiemetodes. Dit het duidelik geword dat vars internodale weefselsnitte wat vir 24 h gefikseer is en daarna voorafbehandeling en hibridisasie ondergaan het, die bepaling van geenuitdrukking tydens alle fases van suikkerrietontwikkeling moontlik gemaak het. Die tweede fase van hierdie studie het aangetoon dat al drie ensieme spesifiek gelokaliseerde uitdrukkingspatrone gehad het in verskillende internodale weefsels en seltipes. Al drie gene is konstitutief uitgedruk in internodes. Die UDP-glukose dehydrogenase en UDP-glukose pirofosforilase transkripte is gelokaliseer na die floeëm elemente, terwyl xileem slegs die UDP-glukose dehydrogenase transkripte bevat het. Al die gene is in die parenchiemselle uitgedruk wat geassosieer is met die vaatbondels en die stingel stoorkompartement, wat moontlik beteken dat die parenchiem selle wat deur die stingel versprei is 'n sentrale netwerk vorm wat direk of indirek koolstofassimileringsprosesse beïnvloed. RNA-en proteïen gel blots op dieselfde internodes het gewys dat internode sewe 'n verskuiwing, van koolstofverbruik na berging, verteenwoordig. Dit word gerllustreer deur die afname in beide transkrip en proteïen vlakke van die drie ensiem in hierdie stadium van ontwikkeling. Alhoewel beide mRNA en proteïen vlakke vir al die ensieme 'n soortgelyke tendens getoon het, het die sellulêre uitdrukking van die ensieme volgens ISH verskil, wat die krag van die tegniek illustreer. Die resultate van hierdie studie het gedemonstreer dat begrip van die kompartementalisasie van metabolisme tussen verskillende weefsel-en seltipes 'n voorvereiste is om die funksie/s van individuele ensieme in komplekse strukture soos die suikerrietstingel te bepaal.

No description available.

No description available.