An assessment of youth empowerment programmes and job creation opportunities: a case of Mhlontlo Local Municipality
- Authors: Mabono, Tumeka Patricia
- Date: 2023-01
- Subjects: Youth -- Employment -- South Africa , Job creation -- Youth -- South Africa , Youth -- Services for -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26874 , vital:66038
- Description: Youth unemployment is a major policy concern in South Africa. This study aimed to assess youth programmes and job creation opportunities in Mhlontlo Local Municipality. This study intended to: 1. Examine the context, purpose, objectives, assumptions and claims of the national youth empowerment policy on job creation, 2. To assess the implementation of the youth empowerment programs in Mhlontlo Local Municipality for improved job creation, and lastly 3. To provide suitable recommendations on improving youth empowerment programmes and job creation in Mhlontlo Local Municipality. This study adopted a qualitative research design, that included and adapted the use of semi structured interviews and focus groups discussions in the context of COVID 19 regulations. The key findings from the analysis of data included the following – • The Mhlontlo Local Municipality has not developed its own local youth development and empowerment policy. • The design limitations in the theory of change of the National Youth Policy negatively affected the implementation of youth programmes in Mhlontlo Municipality • Mhlontlo Local Municipality’s implementation of youth programme failed to achieve its outcomes of creating a sustainable employment for youth. • There was distinct difference between the espoused views of municipal managers and actual experience of implementation of youth programmes the Mhlontlo Local Municipality that impacted negatively on the implementation of the youth development programme. • Their leadership buy-in and championship for youth development in Mhlontlo Local Municipality from selected managers in the municipality and but not from the political office. • There was lack of transparency and communication mechanisms by Mhlontlo Local Municipality the for-youth participation and engagement with of all stakeholders in decision making. , Thesis (MPA) -- Faculty of Management and Commerce, 2023
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- Date Issued: 2023-01
Synthesis of cannibigerol, an antibiotic for methycillin resistant staphylococcus aureus, in continuous flow system
- Authors: Koeberg, Bryce
- Date: 2022-04
- Subjects: Drug resistance in microorganisms , Cannabis -- Therapeutic use -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55866 , vital:54395
- Description: This study focuses on the development of a synthetic version of the cannabinoid cannabigerol (CBG) through continuous flow systems. The compound has exhibited antibiotic properties that have been proven to be a potent killer of gram-positive methicillin-resistant Staphylococcus aureus that drive repeat infections. The cannabinoid kills the superbug by disrupting the cell wall integrity of cells that are drug resistant. Research suggests that CBG is not effective against gram-negative multi-drug resistant bacteria. However, when CBG is administered with polymyxin B, an antibiotic that disrupts the outer membrane of gram-negative bacteria the cannabinoid compound wipes out the drug-resistant gram-negative bacteria, thus revealing the extensive medicinal potential of cannabigerol. Cannabinoids, such as CBG, are present in low yields in the plant, depending on the extraction method, usually less than 5% in most strains. Natural medicines have a low amount of active ingredients due to the lab intensive and time-consuming extraction and isolation process; this has hindered the application of natural products in drug development. A major health concern of the human consumption of cannabis plant extracted cannabinoids is that the plant may be contaminated with microbes, heavy metals and pesticides due to the lack of regulation. Thus, it is proposed that these cannabinoids are synthetically produced through the integration of microfluidic technology, eliminating the presence of pesticides, microbes and heavy metals. The proposed method would even further speed up the rate of production at a lowered cost, produce greater yields of the product compared to extraction procedures / in batch reactions and improve the purity of cannabinoid compounds. This was achieved in flow chemistry whereby the key intermediates (olivetol, a derivative of methyl 6-n-pentyl-2-hydroxy-4-oxo-cyclohex 2-ene-l-carboxylate and cannabigerol) were produced at high conversions (67%, 100% and 34% respectively) in LTF glass microreactors. Cannabigerol was successfully synthesized in flow at high yields compared to literature, however, it was further discovered that the formation of side products was a hindrance to further improvement of the obtained yield in flow. , Thesis (MSc) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
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- Date Issued: 2022-04
The role of circular economy principles in solid waste management: a study of Walmer township
- Authors: Ndarane, Nomonde
- Date: 2022-04
- Subjects: Circular economy , Recycling (Waste, etc.)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58048 , vital:58509
- Description: The maximisation of circular economy strategies brings hope to challenges of solid waste management and poverty alleviation. The purpose of the study was to explore the role of circular economy in solid waste management. A related goal was to enhance an understanding of how Walmer Township community’s use of circular economy principles can serve as a solid waste management strategy. The study holds the practical implication that circular economy contributes significantly to managing solid waste and to sustainable development. An empirical inquiry using a qualitative method was conducted and data was gathered through semi-structured interviews. Four different target groups were selected for this study- waste pickers, key informants (ward councillor and municipal officials), recycling businesses and NGO managers. It was brought to light that circular economy is utilised as both an economic and a solid waste management strategy. The findings show that implementing strategies of circular economy presents opportunities both for businesses and for poverty alleviation. Based on the findings, recommendations are made regarding making circular economy a lucrative business while upholding principles of environmentally friendly waste management strategies. Circular economy has crucial benefits, but it is practiced by few individuals within the community. More research needs to be conducted on how to make circular economy more attractive, especially to the youth. , Thesis (MA) -- Faculty of Business and Economic sciences, 2022
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- Date Issued: 2022-04
Impact of feeding milk once-a-day on growth and development of jersey calves
- Authors: Myburgh, Albertus Petrus
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Calves -- Feeding and feeds
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52095 , vital:43438
- Description: In conventional calf rearing systems calves are fed milk twice a day. Calves are normally housed in a calf shed, kept in individual pens or in groups. The goal should be to limit mor-talities to less than 5% from birth to 30 days. This can be achieved by reducing animal stress, controlling diseases and feeding the animals properly. The immune function can be de-pressed by inadequate nutrition which will increase susceptibility to diseases. Key objective on a dairy farm should be to rear a healthy calf until the calf reaches the optimum mating weight. Digestive disorders and respiratory diseases are the main causes of mortalities of young calves. Jersey calves at Outeniqua Research Farm are kept in movable hutches out-side, for 8 weeks and whole milk is fed only once a day. Although it is common practice to feed milk to calves twice-a-day, Jersey calves are raised with great success by feeding whole milk once-a-day, but proven data was never collected to indicate that feeding whole milk to Jersey calves does not compromise growth or development of calves. Much research was done on feeding of milk to Holstein calves, but little was done on Jersey calves. Research also shows results on feeding of milk replacer rather than whole milk. This raised the question of can whole milk be fed once-a-day successfully to Jersey calves with-out compromising growth and development and what are the advantages of feeding whole milk once-a-day to Jersey calves? , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
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- Date Issued: 2021-04
Modelling the dynamics of Breast Cancer disease with hormone therapy and surgery controls
- Authors: Ngalo, Akhona Sunshine , Mbava,Willard
- Date: 2023-04
- Subjects: Cancer -- Molecular aspects , Breast cancer -- South Africa , Hormone therapy
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61487 , vital:70688
- Description: In this study, we discussed a mathematical model that incorporates important interactions between normal cells, tumor cells, immune cells, and estrogen. The mathematical model was revised to include two control measures; namely surgery and hormone therapy to minimize the number of tumor cells. The model was mathematically analyzed with the premise that the two control measures are positive constants. Locally and globally analyses were performed using a variety of analytical methods to investigate the stability of the breast cancer model. Furthermore, an optimal control problem was formulated and used to determine the best strategy for reducing the number of tumor cells by incorporating hormone therapy and surgery, based on the well-known Pontryagin’s Maximum Principle. The numerical results indicates combining both optimal control measures (surgery and hormone therapy) simultaneously is more efficacious than using single control measure separately in decreasing the number of tumor cells. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2023
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- Date Issued: 2023-04
Cannabidiol: extraction and purification using flow Chemistry
- Authors: Bopape, Karabo
- Date: 2022-04
- Subjects: Supercritical fluid extraction -- South Africa , Cannabis -- Therapeutic use
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55723 , vital:53410
- Description: cannabinoids are of growing interest in research and pharmaceutical applications. Cannabidiol, which is a non-psychoactive cannabinoid, has many pharmaceutical applications. The current and main source of cannabidiol and other cannabinoids is from cannabis and hemp extractions. Current extraction methods involve the use of conventional solvent extraction, which employs the use of organic solvents, in some cases along with mechanical assistance from various equipment. Alternatively, another widely used extraction method is the use of supercritical extraction fluids (SC-CO2 being the most common). An alternative method, which uses chemical synthesis to derivatize cannabidiol to form an intermediate, which is crystalline and can easily be isolated from the extract; the crystalline intermediate can then be deprotected back to pure cannabidiol. In this research, we investigated and adapted the crystallisation method (originally employed by Adams) into continuous flow. In this research, hemp extracts and oilsrich in CBD were used as the source for cannabidiol. This synthesis was adapted into microreactors to synthesise the crystalline intermediate ester product (cannabidiol-3,5-bis-benzoate) which was subsequently reacted in a saponification ester hydrolysis to convert back and isolate pure CBD using continuous flow microreactor technology. Chapter one gives a comprehensive literature review and background on cannabidiol, along with its chemistry and pharmacological benefits in addition to a brief introduction to continuous flow technology with its advantages. Chapter two details the experimental procedures utilised for both batch and continuous flow syntheses. The continuous flow synthesis and subsequent hydrolysis of the ester intermediate, which shows the improvements in comparison to batch; giving higher product recovery (63% CBD), in shorter reaction times (2.5 min for CBD bis-benzoate; 30 min for CBD) is subsequently presented. This is expanded in chapter three with detailed discussions of the results attained during the continuous flow. The concluding remarks, the impact of this study and future work are elucidated in chapter four. , Thesis (MSc) -- Faculty of Science, Biomolecular and Chemical Sciences, 2022
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- Date Issued: 2022-04
The Influence of authentic leadership on the workplace safety culture in the tyre industry of South Africa
- Authors: Gallant, Ryan
- Date: 2022-12
- Subjects: Authentic leadership , Work environment, tyre industry -- South Africa
- Language: English
- Type: Master's theses , Thesis
- Identifier: http://hdl.handle.net/10948/59403 , vital:62078
- Description: The lost-time injury rate in the South African automotive industry is higher than one per million (Harmony, 2010:2). Other manufacturing and construction industries have embarked on safety programmes to ensure awareness amongst their workers. The leaders in industry should have a significant influence to steer the safety culture in the automotive industry. This study examined the relationship between Authentic leadership and a safety Culture in the tyre industry of South Africa. The purpose of the study was to increase the workplace safety culture in the South African tyre manufacturing industry by investigating whether the implementation of an authentic leadership programs would positively influence workplace culture. An exploratory study used a quantitative research design involving an email survey to examine the relationship between Authentic Leadership and Safety Culture. Authentic leadership and the safety climate were assessed using the Norwegian Offshore Risk and Safety Climate Inventory (NORSC), the Authentic Leadership Questionnaire, and the questionnaire from Fulele and Kadam. Seven safety climate dimensions were mapped onto the questionnaire. The data from the questionnaire were analysed using STATISTICA software. According to respondents there is a very strong relationship between Authentic Leadership and the implantation of OHSA standards in the tyre industry in South Africa. In addition, respondents rated their management’s implementation of the organisation’s safety routines highly. There was a high level of motivation among respondents to act in a safe manner. The motivation of workers to work safety is also strong related to authentic leadership. , Thesis (MBA) -- Faculty of Business and Economic Sciences, 2022
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- Date Issued: 2022-12
The design of a special needs school: for children affected by trauma associated with HIV and AIDS in Schauderville, Gqeberha
- Authors: Felton, Mae Sarah
- Date: 2021-12
- Subjects: School buildings -- Design and construction , AIDS (Disease) -- South Africa -- Port Elizabeth , Children with disabilities -- Education -- Port Elizabeth
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/58838 , vital:60171
- Description: HIV and AIDS has been a long-standing and growing pandemic worldwide, but particularly in the context of South Africa. As a result, a pattern of trauma noticeably follows individuals, families and communities, and especially impacts on learners and their experience within the education system. Conventional school environments and buildings often become unaccommodating, harsh and overly-stimulating for learners with traumatic backgrounds and stress. Special needs schools address different disorders and conditions separately, and accommodate a variety of unique demands through teaching interventions and, more importantly, through architecture. This treatise aimed to break away from institutional and conventional architecture by applying theories on child development and architecture, the psychology of space, sensory architecture and trauma-informed design. This treatise positioned itself in empathy and wellness, with concern for the psychological experience of environments for learners, demonstrated through special needs schools, which addressed trauma associated with HIV and AIDS. Hence, this building type was explored to deinstitutionalise educational environments, to identify and address these learners’s specific needs. In realising an architectural intervention with reactive and therapeutic intent, the type of trauma and the relative experiences which triggered it needed to be understood and used to inform and shape comprehensive buildings and environments. This treatise, and the conclusions drawn from it, intended to guide and inform a principle typology and model for future projects of the same nature. As the first of its type, the special needs school location was in Gqeberha and in close proximity to Livingstone Hospital, where the HIV and AIDS cases were the highest. It was situated within the residential zone and schooling district of Schauderville, on the existing site of Adolph Schauder Primary School. The opportunities and challenges in and around this site, along with design principles based on the adopted theories informed an architectural intervention which challenged conventional schooling and design applications in favour of a more empathetic and considerate relationship between learners and architecture. , Thesis (MArch) -- Faculty of Engineering, the Built Environment and Technology, School of Architecture, 2021
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- Date Issued: 2021-12
The design of a performing Arts Centre at Makana’s Kop, in Makhanda
- Authors: Zitumane, Siphosethu Asanda
- Date: 2021-12
- Subjects: Centers for the performing arts -- South Africa -- Makhanda , Art centers -- South Africa -- Makhanda -- Designs and plans
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:59921
- Description: Nearly three decades into democracy, the South African landscape is still embed - ded with the ideologies and systems of apartheid. Separateness has come to de - fine its cartography, drawing clear lines between races. To bridge the racial divide and reconstruct the national identity, the South African government adopted the Rainbow Nation as its brand. This branding did little to address the systemic racism ingrained into its society and landscape. This treatise identifies the limits of the rainbow nation, through an investigation of the intersections between memory, identity, and place. It identifies the imbalance in the expression of certain narratives as barrier in the progression of South Africa’s nation building initiative. Attempting to find a resolution, it offers the design of a performing arts center on Makana’s Kop, Makhanda as a starting point. This archi - tectural endeavor aims to express the oppressed narratives and memories of the Makhandan community. Through exploring how these issues play out in Makhanda, Makana’s Kop is iden - tified as an appropriate site for the architectural manifestation of this treatise. The significance of the site, and its relationship with other monumental structures in this city make it a suitable place for the design of a building of this nature. The inves - tigation is led to examine the architectural and theoretical principles that will ad - opted to aid in making this a successful architectural resolution to the issues iden - tified; which are firstly the need for an architecture to symbolize democracy and the new South African Identity and secondly the need for a container for culture and art for the Makana’s Kop community. The treatise, and thus the the endeavor, is concluded with a presentation and analysis of the final architectural product and the design and technical strategies that were implemented. , Thesis (MArch (Professional) -- Faculty of Engineering, the Built Environment and Technology ,School of Architecture 2022
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- Date Issued: 2021-12
The design and synthesis of novel fluorescent coumarin-based derivatives as chemosensory for the application of toxic metal ion detection
- Authors: Schoeman,Stiaan
- Date: 2023-04
- Subjects: Fluorescent polymers -- South Africa , Polymerization , Chemosensory
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61270 , vital:69851
- Description: The rise of humankind has caused pollution, increasing damage to the environment. The actions of humans over hundreds of years have led to an increase in the release of heavy metal cations in concentrations that are toxic to plants, animals and humans. These toxic metals can find their way into humans’ diets through water sources or bioaccumulation in plants and animals such as fish. Heavy metals such as lead and mercury are known to cause serious health issues when consumed, affecting the functioning of the circulatory and nervous systems and causing developmental disorders. Other metal cations, such as iron and copper, can be found in the human body. However, detrimental health issues can occur when normal concentrations are disturbed (either too high or too low). Iron, for example, can be toxic if in excess in the human body, causing damage to the liver and heart and can cause neuroinflammation and Alzheimer’s disease. Many methods have been employed to detect and measure the concentrations of toxic metal cations. However, these methods are performed in a laboratory and need skilled operators using expensive equipment. This results in long and tedious sample collection, long feedback time and costly analysis. Chemosensors have been researched and proposed as a cost-effective, on-site, real-time alternative for use as metal detectors. Chemosensory can selectively detect specific metal cations and can be sensitive up to the nanomolar range. Various chemosensors have been synthesised and screened for their colourimetric and fluorometric abilities. Colourimetric chemosensors can be used to visually detect cationic and anionic analytes, whereas fluorometric chemosensors are used to detect anions using their emission properties which handheld devices can measure. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
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- Date Issued: 2023-04
A Combined Experimental and Computational Study of Hydridospirophosphorane Ligand Systems Featuring Halogenated Mandelic Acids
- Authors: Maritz, Marius Johann
- Date: 2023-12
- Subjects: Organic compounds -- Synthesis , Heterocyclic compounds , catalysis -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62096 , vital:71911
- Description: The search for new stereoselective catalysts remains important for the isolation of enantiomeric products from racemic mixtures. The need exists for these catalysts to be more efficient, to be more cost effective as well as be stable over time without undergoing changes in molecular structure and selectivity. The purpose of this research project was to experimentally synthesise and characterise asymmetric catalysts for the use in enantioselective synthesis. The catalysts consisted of the main group element phosphorous as central atom, with the phenyl rings of mandelic acid ligands monosubstituted with halogen atoms fluorine, chlorine and bromine in different configurations. Ligand binding resulted in the formation of hydridospirophosphorane structures, from which the molecular properties and binding geometry of these molecules could be explained by the theory of apicophilicity. Characterization was performed by NMR and IR spectroscopy as well as diffraction studies that provided the experimental crystal structures. The structural, energetic and spectroscopy results were compared to the theoretically obtained molecular properties using DFT analysis. Various interand intramolecular interactions that existed between molecules found in crystal packing environments were discussed. Additional properties that were investigated included modelling solvation effects, molecular orbital analysis, Hirshfeld surfaces, orbital and atomic energy and population analysis as well as ESP energy calculations with the optimized crystal structures as input. Molecular overlay comparisons were also performed between the experimental and optimized structures where the effectiveness of various DFT functionals and basis sets could be determined. The method with the best overall cost-to-accuracy ratio was found to be the triple-zeta def2-tzvp basis set with B3LYP functional theory and the addition of Grimme’s dispersion correction. Results indicated differences in crystal packing depending largely on the given halogen atoms present in the substituted phenyl rings, with differences observed in electronegativity and steric effects. One of the crystal systems showed additional interactions with solvent molecules, giving the impression that obtaining crystal void formation was possible. Alterations in the transition state activation energies between the isomers of each molecule were found to be present and supported the theory behind the mechanism of stereochemical induction. The studied compounds were therefore effective in isolating different enantiomeric ligands by means of energy differences between conformers and displayed unique catalytic properties resulting from the phosphorous main group element. The hydridospirophosphoranes conformers responsible for the lowest theoretically calculated activation energy induced crystallization as was seen by diffraction results for all compounds. Even as an intriguing observation, crystallization will largely depend on solubility rather than a specific conformer’s amount in solution. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
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- Date Issued: 2023-12
Expression, partial characterisation and utilization of a GH11 xylanase (Xyn2A) from Trichoderma viride as an additive in monogastric animal feeds
- Authors: Mzimkulu-Ncoyi, Nosabatha Happyness
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422409 , vital:71940
- Description: Endo-xylanases (shortly called xylanases) are a group of glycoside hydrolase enzymes that target β-D-1,4-linkages in the xylan backbone, leading to the production of xylooligosaccharides (XOS) of varying degree of polymerization (DP). Xylan is an indigestible non-starch polysaccharide present in monogastric animal feeds which in high amounts leads to increased digesta viscosity, slow movement of digesta in the intestines, malabsorption of nutrients among other challenges. The aim of this study was to investigate the effect of xylanase 2A (Xyn2A) from Trichoderma viride on broiler chicken feeds, particularly the hydrolysis of the xylan content, reduction of feed viscosity and the effect of produced XOS on eliciting the growth of gut associated probiotic bacteria. Xyn2AE was successfully induced with 0.8 mM isopropyl β-D-1-thiogalactopyranoside (IPTG) and produced in Escherichia coli BL21 (DE3) and Xyn2AC was expressed in tobacco mosaic plants. For the purification of Xyn2AE, an immobilized metal affinity chromatography (IMAC) column and diafiltration using a 3kDa cut-off Amicon filter membranes were used. Xyn2AE and Xyn2AC showed a xylanase active band at a relative weight of 21 kDa. Both enzymes showed high specificity towards soluble wheat arabinoxylan (WAX), with specific activities of 7.61 U/mg for Xyn2AE and 536.5 U/mg for Xyn2AC. Xyn2A kinetic parameters (Vmax and Km) were determined by Michaelis-Menten plots on soluble and insoluble WAX. The Vmax and Km values of Xyn2AC were 1003.01 U/mg and 9.25 mg/mL, 302.89 U/mg and 13.54 mg/mL, respectively. The Vmax and Km values of Xyn2AE for soluble and insoluble WAX were 20.45 U/mg and 12.95 mg/mL, and 8.31 U/mg and 13.15 mg/mL. Xyn2A enzymes displayed optimum activity at pH and temperature parameters of 5.0 and 50°C, respectively, and stability in temperatures ranging between 50 and 80°C and pH 4.0-9.0. Broiler chicken feeds were hydrolysed using Xyn2AE over a 24 h period and analysed using the dinitrosalicylic (DNS) assay, thin layer chromatography (TLC), viscometry and visualized using scanning electron microscope (SEM). The results showed a release of release of XOS xylotriose, xylopentose and xylohexose; enzyme’s ability to decrease the viscosity of the feeds and punched holes of feed surface, which was indicative of xylanase action. XOS produced during hydrolysis was used to study prebiotic effect on selected few bacteria and released short chain fatty acids (SCFAs) were measured. Additionally, SCFAs formation was detected in the presence of XOS as a carbon source for S. thermophilus and L. bulgaricus, whereas B. subtilis formed fewer organic acids in the presence of XOS. The results obtained from this study demonstrated that the supplementation of Xyn2A on broiler feeds has ii a positive effect in decreasing feed viscosity. Furthermore, the results of this investigation will assist the South African poultry farming sector to increase profitability in poultry farming and gain stability in the global trade as far as poultry feed is concerned. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
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- Date Issued: 2023-03-29
Biochemical and genetic analysis of the Mycobacterium smegmatis CnoX Chaperedoxin
- Authors: Watkins, Ariana Heloise Jo
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422403 , vital:71939
- Description: Mycobacterium (M.) tuberculosis (Mtb) encounters numerous physical and chemical stresses associated with host immunity during infection. These include exposure to reactive oxygen, chlorine and nitrogen species, low pH, hypoxia, nutrient starvation, and metal toxicity. Cellular proteins are particularly susceptible to damage by these stresses, and the ability to prevent their irreversible damage is consequently crucial for bacterial growth and survival. Mtb employs a network of proteins that includes chaperones, disaggregases, and proteases to maintain the integrity of its proteome. The chaperedoxin, CnoX, is a recently identified stress-inducible chaperone that combines redox and holdase activities to prevent the over-oxidation and aggregation of proteins in E. coli and other proteobacterial species. In this study, we identified orthologs of the E. coli CnoX (EcCnoX) in Mtb and M. smegmatis (Msm). Bioinformatics analysis of the Mtb and Msm CnoX orthologs (MtCnoX and MsCnoX, respectively) revealed that they possess similar domains, domain architectures and predicted tertiary structures as previously characterised CnoX enzymes, i.e. an N-terminal thioredoxin (Trx) domain fused to a C-terminal TPR-motif containing domain. The EcCnoX, MsCnoX, and MtCnoX enzymes were expressed as recombinant, His-tagged proteins in E. coli and purified to near homogeneity. Biochemical analysis of the recombinant CnoX enzymes revealed that the MsCnoX and MtCnoX both lack thiol-disulphide oxidoreductase (thioredoxin) activity, as evidenced by their inability to catalyse the reduction of the disulphide bonds of insulin in vitro. Both mycobacterial CnoX enzymes displayed activity as chaperones (holdases) during thermal aggregation assays of the model substrate, malate dehydrogenase (MDH). In contrast to previously reported findings for EcCnoX, the holdase activity of the mycobacterial CnoX enzymes was constitutive and did not require exposure to hypochlorous acid (HOCl) for activation. To establish the physiological role of CnoX in Msm, cnoX knockdown (KD) and knockout (KO) mutants were generated using CRISPRi-mediated gene silencing or homologous recombination, respectively. Consistent with previous findings, CnoX activity was not essential for the growth of Msm under conventional growth conditions. Reducing or eliminating CnoX activity in the Msm KD or KO mutants, respectively, did not confer increased sensitivity to HOCl as has been observed for an E. coli cnoX mutant. Reduced CnoX activity in Msm did, however, confer sensitivity to the superoxide generator, plumbagin, and front-line antitubercular drugs rifampicin and isoniazid. The combination of biochemical and physiological data presented suggests that MsCnoX may function as a holdase for substrates following proteotoxic damage induced by certain types of oxidants, a line of investigation that will be pursued in future studies. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
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- Date Issued: 2023-03-29
Implications of changing land use and introducing extralimital giraffe on vegetation in the subtropical thicket, South Africa
- Authors: Trafford, Bronwyn Kate
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422356 , vital:71935
- Description: Land use change has increased in southern Africa as many livestock farms convert to game reserves, to restore degraded and overgrazed lands. This leads to a change in herbivore communities with potential positive and negative consequences for vegetation and landscape productivity. This study aimed to look at the effect of land use change and subsequent herbivore community changes, on thicket vegetation structure, composition, and landscape productivity. To attain the study objectives, data were collected from four game reserves and their adjacent livestock farms within the Eastern Cape province in South Africa. These sites were selected because they are within the Subtropical Thicket biome (similar vegetation) and were once used for livestock farming. At each study site, vegetation composition and structure were assessed using a unique bush clump sampling technique along fence line contrasts. Six plots were sampled at each site, three plots on the game reserve lands and three plots on the adjacent livestock farmlands during the dry (July/August 2020) and wet (January/February 2021) seasons. The Normalized Difference Vegetation Index (NDVI), in-situ leaf area index (LAI) and the fraction of intercepted photosynthetically active radiation (FIPAR), were used to assess vegetation productivity between the two land use types. Additionally, diet of an extralimital herbivore, giraffe (Giraffa camelopardalis), was assessed during contrasting seasons (dry and wet) to infer the role this species might have on these landscapes. The diet of giraffes was assessed through field observations, recording plant species that giraffes were feeding on. Floristic results showed that there were no differences in vegetation structure, species composition and richness between the two land types. There was no difference in the overall diversity of plant species on the game reserves than in the adjacent livestock farms. The primary productivity was greater on the game reserves compared to the livestock farms. Field observations of giraffe feeding showed that they fed predominantly on Vachellia karroo followed by Searsia longispina. Their diets did not differ between the two seasons. My study provides an insight into the effects of changing land use and this information can be used to infer the extent to which these changes might have on restoration of degraded landscape and how land use changes may be effective in restoring the degraded thicket vegetation caused by overgrazing and overstocking of domestic livestock. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
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- Date Issued: 2023-03-29
Photodynamic therapy using morpholine substituted porphyrins in the presence of cancer specific molecules linked to graphene quantum dots
- Authors: Magaela, Ngwanabjala Bridged
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422486 , vital:71947
- Description: This thesis reports on the synthesis, characterization, photophysiochemical properties of morpholine substituted symmetrical and asymmetrical porphyrins. The synthesized porphyrins are conjugated to cancer selective biomolecules (folic acid and biotin) which are linked to nitrogen doped graphene quantum dots, as potential photosensitizers for photodynamic therapy (PDT). The symmetrical morpholine porphyrin complexes 2 (Sn(IV) 5,10,15,20 tetra-4-morpholinyl porphyrin) and 3 (Zn 5,10,15,20 tetra-4-morpholinyl porphyrin) had the same substituent but different central metals, and they were both conjugated to biotin decorated nitrogen doped graphene quantum dots (B-NGQDs), however complex 2 (Sn(IV) 5,10,15,20 tetra-4-morpholinyl porphyrin) was conjugated to B-NGQDs through an ester bond and complex 3 (Zinc 5,10,15,20 tetra-4-morpholinyl porphyrin) through 𝜋-𝜋 stacking. The effect of asymmetry was studied by comparing complex 3 (Zn 5,10,15,20 tetra-4-morpholinyl porphyrin) and complex 5 (Zn 5- bromophenyl-10-15-20-(tris-4- morpholinyl) porphyrin). Complex 5 (Zn 5- bromophenyl-10-15-20-(tris-4- morpholinyl) porphyrin) was an asymmetric porphyrin with morpholine and bromine as substituents. It was observed that asymmetry enhances singlet oxygen quantum yield and PDT activity. It was also observed that folic acid is a better targeting biomolecule when compared to biotin, and this was studied by comparing complex 3 conjugated to B-NGQDs and complex 3 conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs). 3-FA-NGQDs had a better cellular uptake and PDT activity. , Thesis (MSc) -- Faculty of Science, Chemistry, 2023
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- Date Issued: 2023-03-29
Fiscal consolidation and economic growth: a comparison of South Africa and selected three OECD countries
- Authors: Mphaphuli, Zeb Junior Rabelani
- Date: 2023-04
- Subjects: Fiscal consolidation , Economic growth -- South Africa , OECD countries
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62142 , vital:72001
- Description: The study examined the relationship between fiscal consolidation and economic growth in South Africa (SA) in comparison with the Organisation for Economic Cooperation and Development (OECD) countries. The study emphasizes the use of fiscal consolidation as a tool to stimulate economic growth and reduce the budget deficit, focusing on the reforms of public revenues and expenditures. Moreover, the study employed the panel Autoregressive Distributed Lag (PARDL) model to explore the relationship between fiscal consolidation and economic growth in SA and three OECD countries from the period 1990 - 2018. The cointegration analysis confirmed the existence of cointegration between the variables which suggested that there is a long-run relationship among the variables. As a result, both long and short run dynamic models were evaluated. The result of the study shows that fiscal consolidation positively affects economic growth in South Africa in the long run, whilst in OECD countries fiscal consolidation negatively affects economic growth, both in the short and long run. Low government debt in South Africa due to lower deficit translated to a higher economic growth whilst higher debt level in OECD countries due to higher government spending translated to higher economic growth, one of the main differences in the relationship between fiscal consolidation and economic growth in South Africa and OECD countries is their spending pattern. Majority of South Africa’s budget is spent on inefficient state-owned enterprises, which have accounted for the bulk of government contingent liabilities, resulting in high borrowing costs, which consequently lead to high borrowing cost, thus the rising central government debt as a percentage of GDP. Unlike in SA, OECD countries spend towards capital expenditure specifically in priority areas such as infrastructure, Technology, and transport hence their high debt levels result in higher economic growth. In attempt to stimulate South Africa's economic growth, it is recommended that South Africa implement effective fiscal consolidations based on expenditure adjustments rather than revenue adjustments, as expenditure adjustments are more likely to reduce deficits and debt-to-GDP ratios and are more effective. In addition, the South African fiscal stimulus package can be used to invest more in infrastructure to increase private capital accumulation and stimulate economic growth. However, South Africa must exercise caution when reducing expenditures to avoid a reduction in development spending, which could lead to a decline in unemployment. , Thesis (Ma) -- Faculty of Faculty of Business and Economic Sciences, 2023
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- Date Issued: 2023-04
Factors that influence the success of total quality management (TGM) practices in a South African (SA) automotive organisation
- Authors: Makone, Tlangelani Sandra
- Date: 2023-04
- Subjects: Automotive Industry , Total Quality Management
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62113 , vital:71996
- Description: The South African automotive industry is a key driver of the economy and industrialisation of the country. The Covid-19 pandemic has had adverse effects on many industries globally. In the automotive industry, Covid-19 affected the supply chain resulting in a shortage of semi-conductors, which are essential in the microchips used in the vehicle assembly process. The delays in supply resulted in decreased production volumes and thus a decline in sales which has had an adverse effect on the economic growth of the industry. Therefore, the automotive industry must be sustainable and agile to be competitive globally. This study aimed to focus on total quality management (TQM) practices as a tool for competitive advantage. TQM is significant for sustainability, business continuity and competitive advantage. The study highlights the relevance of TQM practices in the global automotive industry and in South Africa where the study was performed. The organisations at the base of the study are multinational original equipment manufacturers (OEMs) that manufacture passenger vehicles for both local and export markets. This quantitative study investigated the relationship between leadership support, quality culture, education and training, structure and resources, and strategic quality plan as the independent variables and TQM practices as the dependent variable. A closed-ended online survey with 70 respondents was employed to collect the data from the OEMs. The findings are that there is a positive and significant correlation between the variables. Leadership support, quality culture and strategic quality planning have more influence on the success of TQM practices. Education and training, and structure and resources have a moderate influence on TQM practices. Managers in quality assurance and production in automotive organisations need to prioritise leadership support, quality culture and strategic quality planning for TQM practices to succeed. , Thesis (MA) -- Faculty of Faculty of Business and Economic Sciences, 2023
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- Date Issued: 2023-04
Identification of novel Arf1 GTPase inhibitors for cancer target validation
- Authors: Mqwathi, Nomxolisi Vuyokasi
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424666 , vital:72173
- Description: The key regulators of both anterograde and retrograde vesicular traffic, adenosine diphosphate-ribosylation factors (Arfs), also coordinate various signalling pathways and regulate cellular processes required for cell survival and function. In addition to its role in mediating secretory trafficking in the Golgi apparatus, the involvement of Arf1 in signalling pathways that contribute to the formation and progression of cancer has become apparent, and the overexpression and deregulation of Arf1 activity has been associated with cancer cell invasion, proliferation and metastasis. As with other small GTPases, Arf1 must cycle back and forth between an inactive (GDP-bound) and active (GTP-bound) conformation to carry out its function. However, the cycle of Arf1 inactivation and activation is controlled by Arf GTPase activating proteins (Arf-GAPs) that stimulate Arf1 to hydrolyse the bound GTP to GDP and Arf guanine nucleotide exchange factors (Arf-GEFs) that facilitate GDP for GTP exchange on Arf1, respectively. The identification of Arf1 inhibitors that indirectly disrupt Arf1 function by blocking its interaction with Arf-GAPs or Arf-GEFs has generated interest in their use as possible anti-cancer agents. The suppression of Arf1 activation (by targeting Arf-GEFs) has been investigated as a potential cancer therapeutic target and resulted in inhibitor compounds that have micromolar-range activity against cancer cells and targets and promising results in mouse models, but experience problems with bioavailability when used in vivo. This motivates the search for novel Arf1 inhibitors for validation purposes to question whether Arf1 is a viable target for cancer therapy. The purpose of the study was to employ a recently developed colourimetric screening assay to identify inhibitors of Arf1 activation (Arf-GEF inhibitors) and deactivation (Arf-GAP inhibitors), with a focus on evaluating the potential of Arf1 deactivation as an entirely novel anti-cancer target. The proteins required for the assay (Arf1, Arf-GEF and -GAP domains and a reporter protein, GST-GGA3) were expressed in E. coli. and purified using affinity chromatography. The assay could detect the activation of Arf1 by the catalytic Sec7 domain of the three Arf-GEFs chosen for this study, but reproducibility was compromised by the occasional spontaneous activation of Arf1 in the absence of the Arf-GEFs. By contrast, the assay could reproducibly detect Arf1 deactivation by an Arf-GAP domain (Arf-GAP1GAP) and was subsequently used to screen a library of α-helix mimetics. Thirteen hit compounds with IC50 values ranging from 0.53 to 20.95 μM were found to inhibit Arf-GAP1GAP-mediated stimulation of GTP hydrolysis by Arf1-GTP in this assay format, however, they did not effectively suppress the proliferation of three tested cell lines (HeLa, MCF-7 and MCF-12A). Interestingly, the results obtained from fluorescence microscopy studies suggested that the compounds disrupt Golgi structure and Arf1 localisation, presumably by keeping Arf1 in its active conformation by blocking Arf-GAP1 function. This suggests that the compounds affect Arf1 function in cells, and may be used to explore the feasibility of targeting Arf1 deactivation for anti-cancer purposes in a wider range of cell lines and experiments. It has been reported that Arf-GAP1 inhibition is associated with the suppression of cell migration, and the potential of the compounds as metastasis inhibitors may also be explored. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
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- Date Issued: 2023-10-13
The development of a plate-based assay to detect the activation status of ARF1 GTPase in Plasmodium falciparum parasites
- Authors: Du Toit, Skye Carol
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424654 , vital:72172
- Description: The exponential rise in antimalarial drug resistance in the most infectious malaria species, Plasmodium falciparum, has emphasised the urgency to identify and validate novel drug targets that decrease parasite viability upon inhibition. In addition to several publications indicating that the regulation of human Arf1 GTPase activity (mediated by ArfGEFs and ArfGAPs) serves as a pertinent drug target for cancer research, the identification of Arf1 and its regulatory proteins in Plasmodium falciparum led to the question whether these protein homologs could be exploited as drug targets for anti-malarial drug therapies. To investigate this prospect, the establishment of a novel in vitro colorimetric ELISA-based assay was needed to be able to detect changes in the activation status of P. falciparum Arf1 (PfArf1) in parasite cultures exposed to potential Arf1 inhibitors. By exploiting the selective protein interaction that occurs between active GTP-bound Arf1 and its downstream effector, GGA3, an assay protocol was established that could be used to detect the activation status of purified, truncated PfArf1 obtained from E. coli and endogenous PfArf1 sourced from parasite lysates. The assay relies on the use of anti-Arf1 antibodies to detect the binding of active PfArf1 in the lysates of inhibitor-exposed cultured parasites to GST-GGA3 immobilised in glutathione-coated plates. The results from chemical validation experiments conducted using the novel assay developed in this study, using the known ArfGEF inhibitor brefeldin A (BFA) and ArfGAP inhibitors Chem1099 and Chem3050, yielded the anticipated results: decrease in active PfArf1 after parasite incubation with the ArfGEF inhibitor, and increased active PfArf1 after ArfGAP inhibition. The results confirmed PfArf1 as a potential anti-malarial drug target and encourages the further development of this assay format for the identification of subsequent inhibitors in library screening campaigns. Additional pilot experiments were conducted to further explore whether the assay could detect the activation status of human Arf1 using HeLa cell lysates and to provide further evidence that the assay could be exploited as a tool in the identification of Arf1 GTPase inhibitors with BFA and the known ArfGAP inhibitor, QS11. The results suggested that, while the assay can detect the increase in active cellular Arf1 due to the inhibition of human ArfGEF following BFA treatment, subsequent treatment with QS11 showed no evidence of a reduction in active human Arf1 due to ArfGAP inhibition. Further experimentation is required to investigate the ability the assay to confirm inhibition of human Arf1 deactivation by ArfGAP inhibitors and develop the assay as a useful tool to support cancer drug discovery, in addition to antimalarial drug discovery projects aimed at Arf1. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
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- Date Issued: 2023-10-13
Application of web design techniques and best practices in implementing web development, maintenance and enhancement of RUBi websites and web application systems
- Authors: Tshabalalala, Thulani
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424688 , vital:72175
- Description: The popularity of the web has seen various fields, such as the sciences taking advantage of this resource to further their scientific endeavours. This has seen science groups moving into developing websites and web applications, and such a group is the Research Unit in Bioinformative (RUBi). With the use of the web, the development and maintenance of whatever web-related tools become inevitable, given the continuous changes in the web space. This continuous evolution of web development and maintenance will come with techniques, principles and standards which will not only enable faster development of web entities but also ensure that modern hardware, fulfilment of the requirements to use such hardware and modern concepts are incorporated into forming web tools that enable such progression. Furthermore, introducing the previously mentioned progress of the web becomes an essential part of its development and maintenance. This paper did implement the processes of progressing the web using the technique of documentation and version control systems. The web development for the COVIDRUG website was done for the Covidrug-Africa Consortium (COVIDRUG) using the Django webdevelopment framework. The RUBi website and the MDM-Task we band the Job Management System (JMS) web applications were maintained for the maintenance aspect. Archives brought value regarding the traceability it provides of the various web-related aspects. The development showed a website’s potential value, particularly for research groups. The maintenance carried out showed how different techniques and approaches could be used in different maintenance prospects to achieve set objectives. The development and maintenance resulted in websites and web applications that have the features stated in their respective maintenance plans. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
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- Date Issued: 2023-10-13