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New genetic tools to engineer starch production in crops
No full textPhilosophiae Doctor - PhDStarch is a major carbohydrate reserve in many plants, providing energy during heterotrophic growth and it is contained in large amounts in staple foods such as potatoes, wheat, maize, rice, sorghum and cassava. Apart from being a major product for use in the food industry, starch is also attracting interest from the biofuels industry as a source of bioethanol. This study reports on the development of genetic tools
aimed at increasing starch production in sorghum (Sorghum bicolor L Moench), a crop of key agronomic importance worldwide by exploiting a new discovery of a transcription factor gene that regulates starch accumulation in Arabidopsis thaliana namely LEAFY COTYLEDON I (LECl). Ectopic over expression of this gene in arabidopsis has previously been shown to induce a massive hyper accumulation of starch in vegetative tissues. Therefore, we set out to investigate the function of its orthologous gene counterpart in sorghum with the aim of manipulating starch yield directly. Deduced protein sequence analyses showed that the putative sorghum LEAFY COTYLEDON I gene (SbLEC1) cloned in this study shares an overall high amino acid sequence identity (70 %) with the arabidopsis LEC 1, while the functional central B domain shows an even higher percentage sequence identity (91 %) with the same region of arabidopsis LEC 1. The putative SbLEC1 protein shares 14 out of the 16, signature ammo acids characteristic of the Central B Domain with arabidopsis. Furthermore, the putative SbLEC1 protein was also shown to share a significantly high sequence identity (> 80 %) with other well-characterized LEC1 protein sequences from organisms such as maize, rice, rapeseed as well as other organisms documented in the NCB I database. Similarly, much of the sequence similarity lies within the functional central B domain compared to any other region. Gene expression profiling using semi-quantitative PCR showed that SbLEC1 transcripts accumulated in developing seeds as well as in embryogenic calli tissue and no SbLEC 1 transcripts were detectable in leaf, root or
sheath tissue. In order to confirm that the identified transcription factor is a functional ortholog, the full cDNA encoding putative SbLEC 1 transcription factor was identified, isolated and cloned from the sweet sorghum MN 1812 genotype. Plant transformation gene constructs based on the pCAMBIA1305.2 binary vector harbouring the transcription factor gene under the control of different promoter sequences were then assembled and immobilized into Agrobacterium tumefaciens strain LBA4404 in preparation for sorghum and arabidopsis transformation. Transient GUS expression studies showed that the five SbLEC1 gene constructs developed in this study were successfully transformed into arabidopsis (Ws ecotype) and sorghum (variety MN1812) callus and cell suspension cultures. The transformed tissues thus
represent essential tools that are useful to evaluate the effect of over expressing the putative SbLEC1 protein. Transient GUS expression assays also further revealed differences in efficiency among promoters in driving transgene expression. Transient GUS activity was highest for the maize ubiquitin promoter (MUbi1), followed by the sorghum LEC1 promoter (SLECP), the arabidopsis LEC1 promoter (ALECP) and
lastly the maize alcohol dehydrogenase promoter (MAdh1). The ability of the putative SbLEC 1 gene to complement the arabidopsis lecI mutation was also investigated and our findings were not conclusive as they only revealed partial complementation. A detailed comparison of SbLECI full cDNA sequences isolated and cloned from twenty-eight different F2 population plants from different sorghum varieties revealed the existence of sequence variation within the SbLEC 1 gene, which appeared to be allelic. The allelic variation was further shown to affect the amino acid composition of the putative SbLEC 1 protein. Heterologous protein expression studies of the SbLECI gene using an E. coli system showed that the predicted 29.16 kDa putative SbLEC 1 protein could be expressed in vitro both as an development of an efficient tissue culture protocol is a prerequisite for plant genetic engineering, this study also reports on the evaluation of thirteen sorghum genotypes from different genetic backgrounds for their in vitro culture response. A tissue culture protocol for three previously unexplored sorghum genotypes namely Agricol white, AS4 and MNI812 was established. The effect of plant genotype, explant and medium
composition on in vitro culture response was highly significant (95 % Cl) in this study. Taken together, the findings in our study demonstrate efforts to draw a baseline foundation for the development of molecular technologies that can be used to increase starch production in sweet sorghum as a water efficient and sustainable feedstock for biofuel production
New genetic tools to engineer starch production in crops
Get PDFPhilosophiae Doctor - PhDStarch is a major carbohydrate reserve in many plants, providing energy during heterotrophic growth and it is contained in large amounts in staple foods such as potatoes, wheat, maize, rice, sorghum and cassava. Apart from being a major product for use in the food industry, starch is also attracting interest from the biofuels industry as a source of bioethanol. This study reports on the development of genetic tools
aimed at increasing starch production in sorghum (Sorghum bicolor L Moench), a crop of key agronomic importance worldwide by exploiting a new discovery of a transcription factor gene that regulates starch accumulation in Arabidopsis thaliana namely LEAFY COTYLEDON I (LECl). Ectopic over expression of this gene in arabidopsis has previously been shown to induce a massive hyper accumulation of starch in vegetative tissues. Therefore, we set out to investigate the function of its orthologous gene counterpart in sorghum with the aim of manipulating starch yield directly. Deduced protein sequence analyses showed that the putative sorghum LEAFY COTYLEDON I gene (SbLEC1) cloned in this study shares an overall high amino acid sequence identity (70 %) with the arabidopsis LEC 1, while the functional central B domain shows an even higher percentage sequence identity (91 %) with the same region of arabidopsis LEC 1. The putative SbLEC1 protein shares 14 out of the 16, signature ammo acids characteristic of the Central B Domain with arabidopsis. Furthermore, the putative SbLEC1 protein was also shown to share a significantly high sequence identity (> 80 %) with other well-characterized LEC1 protein sequences from organisms such as maize, rice, rapeseed as well as other organisms documented in the NCB I database. Similarly, much of the sequence similarity lies within the functional central B domain compared to any other region. Gene expression profiling using semi-quantitative PCR showed that SbLEC1 transcripts accumulated in developing seeds as well as in embryogenic calli tissue and no SbLEC 1 transcripts were detectable in leaf, root or
sheath tissue. In order to confirm that the identified transcription factor is a functional ortholog, the full cDNA encoding putative SbLEC 1 transcription factor was identified, isolated and cloned from the sweet sorghum MN 1812 genotype. Plant transformation gene constructs based on the pCAMBIA1305.2 binary vector harbouring the transcription factor gene under the control of different promoter sequences were then assembled and immobilized into Agrobacterium tumefaciens strain LBA4404 in preparation for sorghum and arabidopsis transformation. Transient GUS expression studies showed that the five SbLEC1 gene constructs developed in this study were successfully transformed into arabidopsis (Ws ecotype) and sorghum (variety MN1812) callus and cell suspension cultures. The transformed tissues thus
represent essential tools that are useful to evaluate the effect of over expressing the putative SbLEC1 protein. Transient GUS expression assays also further revealed differences in efficiency among promoters in driving transgene expression. Transient GUS activity was highest for the maize ubiquitin promoter (MUbi1), followed by the sorghum LEC1 promoter (SLECP), the arabidopsis LEC1 promoter (ALECP) and
lastly the maize alcohol dehydrogenase promoter (MAdh1). The ability of the putative SbLEC 1 gene to complement the arabidopsis lecI mutation was also investigated and our findings were not conclusive as they only revealed partial complementation. A detailed comparison of SbLECI full cDNA sequences isolated and cloned from twenty-eight different F2 population plants from different sorghum varieties revealed the existence of sequence variation within the SbLEC 1 gene, which appeared to be allelic. The allelic variation was further shown to affect the amino acid composition of the putative SbLEC 1 protein. Heterologous protein expression studies of the SbLECI gene using an E. coli system showed that the predicted 29.16 kDa putative SbLEC 1 protein could be expressed in vitro both as an development of an efficient tissue culture protocol is a prerequisite for plant genetic engineering, this study also reports on the evaluation of thirteen sorghum genotypes from different genetic backgrounds for their in vitro culture response. A tissue culture protocol for three previously unexplored sorghum genotypes namely Agricol white, AS4 and MNI812 was established. The effect of plant genotype, explant and medium
composition on in vitro culture response was highly significant (95 % Cl) in this study. Taken together, the findings in our study demonstrate efforts to draw a baseline foundation for the development of molecular technologies that can be used to increase starch production in sweet sorghum as a water efficient and sustainable feedstock for biofuel production
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
CHALLENGES CONFRONTING LOCAL AUTHORITIES IN SOLID WASTE MANAGEMENT: THE CASE OF DANGAMVURA RESIDENTIAL AREA, MUTARE, ZIMBABWE
Get PDFSolid waste management has become one of the major challenges in both public circles and environmental health at the global level. The extent of the problems being faced as a result of improper solid waste management cannot be understated for example the illegal dumping and burning of municipal waste has become a common phenomenon in most Zimbabwean towns and cities. Studies regarding solid waste management have been widely researched by various scholars across the globe. In Zimbabwe, studies regarding solid waste management have been studied by scholars like Mlaudzi (2017) and Mutsvanga, et al. (2018) among others. Most of the studies focus on major urban centres and lack much information on residential areas. This study focuses on the challenges faced by local authorities in solid waste management in Dangamvura, Mutare. The main objectives of the study include: exploring the challenges being faced by the city of Mutare in solid waste management within the Dangamvura residential area, determining how these challenges are affecting the community and assessing the strategies and policies adopted by the city council to address these challenges. The researcher employed the mixed method of data collection and 60 participants took part in the research. The key informants were drawn from the city of Mutare. The main challenges which were being faced by the council in solid waste management in Dangamvura included poor community engagement, understaffing, urban sprawl, political interference, shortage of resources and natural hazards. These challenges affected the residents in a number of ways which included: disease outbreaks through water contamination, loss of natural beauty of the area and inconsistency in refuse collection. Various efforts were made to improve the state of service delivery in Dangamvura which included environmental education, law enforcement, motorizing cleansing, purchasing new refuse trucks and provisions of bins. The recommendations that have been provided include depoliticizing the issue among others that have been listed at the end of this study. Article visualizations
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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