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Composition and physiological roles of gut microbiota in the False Coding Moth (Thaumatotibia leucotreta)

- Richardson, Perryn Heather

Authors: Richardson, Perryn Heather
Date: 2023-10-13
Subjects: False codling moth , Microbiomes , Insect physiology , Citrus Diseases and pests South Africa , Biological pest control , Cryptophlebia leucotreta
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/424457 , vital:72155
Description: Gut microbiota can have a profound influence on host performance, behaviour and fitness. For False Codling Moth (FCM), Thaumatotibia leucotreta (Lepidoptera: Tortricidae), a major pest of citrus in South Africa, little work has been undertaken to date on gut microbe diversity or its influence on the host. This thesis aimed to i) characterise the gut microbiome of FCM under laboratory conditions and in FCM from the field, ii) and produce moths with reduced gut microbiota through egg dechorionation, which was followed by iii) the measurement of a suite of physiological traits, namely mass, survival and thermal stress in FCM from normal laboratory, dechorionated laboratory and field collected larvae that may be indicative of overall field performance. We aimed to directly test the hypothesis that gut microbial diversity partly determines insect performance and fitness by measuring its effects on growth, development, and tolerance to cold temperatures in FCM. FCM eggs that underwent dechorionation with sodium hypochlorite had an overall effect on larval survival, egg morphology and both larval and adult moth physiological measures. Increasing concentrations of sodium hypochlorite significantly decreased insect survival, (𝜒2(1, n = 10 850) = 21.724, p-value < 0.0001), with a concentration of ≈3.69% as the concentration limit (p-value < 0.001). Successful dechorionation of FCM was achieved with a wash of sodium hypochlorite at around 3.69% concentration and was visually confirmed by reduction of FCM egg surface area, (𝜒2(25, n = 260) p-value < 0.0001) and Scanning Electron Micrographs of the egg morphology. The gut microbiome of FCM from the different focus treatments was successfully characterized. Identification of the dominant bacterial families in these microbiomes revealed Xanthobacteraceae, Beijerinckiaceae and Burkholderiaceae in both the laboratory reared and field collected larvae, which suggests their systematic association with T. leucotreta. The most abundant genera were revealed as Bradyrhizobium, Methylobacterium and Burkholderia-Caballeronia-Paraburkholderia. Comparison of larval mass showed that treatment (dechorionated or not) had a significant effect on larval mass (𝜒2(2, n = 230) = 22.703, p-value < 0.001), field larvae were heavier than both control larvae and larvae with a disrupted gut microbiome. However, adult insects with a disrupted gut microbiome had more mass than individuals from the control and field-collected larvae with intact gut microbiomes (𝜒2(2, n = 230) = 39.074, p-value < 0.001). Despite the difference in mass between larval treatments, there was no significant difference in relative protein (𝜒2(2, n = 24) = 5.680, p-value = 0.06), carbohydrate (𝜒2(2, n = 24) = 3.940, p-value = 0.14) or lipid (𝜒2(2, n = 24) = 6.032, p-value = 0.05) content between individuals from the control and dechorionated treatments and field-collected individuals. Turning to thermal physiology, insects collected from the field took significantly longer to recover from chill coma than both laboratory treatments with intact and disrupted gut microbiomes (𝜒2(2, n = 129 = 39.659, p-value < 0.001). In addition, exposure to cold stress showed that treatment had a significant effect on insect mortality (𝜒2(2, n = 272) = 9.176, p-value = 0.01), with individuals from the control and dechorionated treatment being less likely to die after experiencing cold stress compared to field-collected individuals. Differences in the mass and thermal tolerance of insects with intact and disrupted gut microbiota suggest that gut microbiota may play an important role in the cold performance of T. leucotreta, and these findings constitute the basis for future molecular work on the functions of these bacterial taxa. This research highlights the need for consideration of the effects of T. leucotreta microbiome in current pest control programs. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
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Date Issued: 2023-10-13

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The practical implications of taxing the informal sector in Zimbabwe

- Mashate, Fredy

Authors: Mashate, Fredy
Date: 2022-10-14
Subjects: Informal sector (Economics) Taxation Zimbabwe , Small business Taxation Law and legislation Zimbabwe , Tax administration and procedure Zimbabwe , Taxpayer compliance Zimbabwe , Taxation Public opinion , Zimbabwe. Revenue Authority , Informal sector (Economics) Taxation Tanzania , Informal sector (Economics) Taxation Ghana
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/357594 , vital:64758
Description: The taxation of informal sector business is increasingly becoming a topical issue in many developing countries, and Zimbabwe is no exception. The Zimbabwean government has been experiencing shrinking revenue in the wake of an increased informal sector and a declining formal sector. In an effort to broaden the tax base and increase revenue for government in Zimbabwe, presumptive tax levied against certain informal sector activities was first introduced in 2005 and later expanded to other sectors. Despite the effort, the informal sector has responded with low tax morale and non-compliance, which creates the need to reassess the current administrative strategies in a bid to build a successful tax system for the informal sector. The main goal of the research is to establish clear, innovative and practical administrative strategies that can be adopted by the Zimbabwe Revenue Authority in taxing the informal sector in Zimbabwe. An initial investigation was done to identify the current state of affairs in relation to informal sector taxation in Zimbabwe. A number of challenges were recorded and the research the sought to learn from examples of recent innovation in administrative strategies successfully applied in taxing the informal sector in other jurisdictions like Tanzania and Ghana. Learning from these examples, a number of practical administrative strategies that are mindful of the Zimbabwean economic context were proposed. , Thesis (MCom) -- Faculty of Commerce, Accounting, 2022
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Date Issued: 2022-10-14

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An aesthetic exploration of skin as the abject other

- Knickelbein, Jonel, Wentzel, Andrieta

Authors: Knickelbein, Jonel , Wentzel, Andrieta
Date: 2022-04
Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/55341 , vital:51913
Description: The purpose of this dissertation is to explore the notion of skin, its functions, and dysfunctions as the basis for the conceptual as well as theoretical output of this work. The problem statement aims to establish whether cathartic relief can be achieved through the process of visualizing skin as the abject other. Every human and animal is born with skin. The epidermis is the outermost of three layers that make up the skin. This layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through trans epidermal water loss (Bouwstra, 2003:34). Although the human skin serves as a protective barrier, the skin itself can be a source of physical as well as emotional pain. I was born with Epidermolysis Bullosa (EB), a rare and genetic skin condition that results in extensive blistering and wounding of the skin caused by mechanical trauma. The process of friction, wounding and healing has been a part of my physical being and daily affairs since I can remember. According to Cervero, ―Pain is our most powerful emotion, an essential learning tool, a major factor in our relationship with the world, and the source of much of our social behavior‖ (2012:34).I believe that my personal experience with EB has affected how I view the functions and importance of skin. In this study I explore the purposes and functions of skin through both a physical and psychological lense I also investigate the role skin plays in forming identity. The works of artists such as Frida Kahlo, Eva Hesse and Alina Szapocznikow are carefully considered in understanding different approaches and mediums used in engaging with the experience of catharsis. Investigations are made into theories on Abjection, the Skin-Ego, Materiality and Catharsis in order to sufficiently inform and shape the outcomes of the creative process. The creative and research processes have resulted in the body of artwork, entitled Skin- deep: transforming dysfunction into function, which is presented as a narrative installation and exhibition of abstract sculptural work. Ultimately, the body of work and research attempts to validate that the notion of skin (as the abject other skin) can be artistically explored to achieve cathartic relief. , Thesis (MA) -- Faculty of Humanities, School of Visual and Performing Arts, 2022
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Date Issued: 2022-04

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The design of a social incubator in Lombok, Utrecht, the Netherlands - a regeneration of 'terrain vague' space

- Holm, Alma

Authors: Holm, Alma
Date: 2021-12
Subjects: Terrain vague—Netherlands – designs and plans , Landscape architecture --Netherlands
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/58705 , vital:60021
Description: ‘Terrain vague’, a collective term coined by Spanish architect Ignasi Sola-Morales, denotes the unused, forgotten spaces located in between categorised spaces and artefacts. It is an omnipresent typology found within productive structures of urban environments, yet ‘mentally exterior to them’ , in other words detached from the energies that surround them. Physically, these spaces are identified as traffic circles, parking lots, open plots, spaces underneath highways, or forgotten buildings. These spaces have a strangeness to them, the detachedness from the conventions of their surrounds gives them a sense of mobility, freedom, and liberty. This creates a perfect environment for the exploration of new ideas. Therefore, this unrealised potential makes these spaces best understood as a relationship between the absence of use, and the sense of expectancy. Mobile interconnectedness has created a transition in the way we work and live together. According to Raumlabor (2018), these new socio-cultural and economic challenges demand new types of solutions which cannot be solved by top-down monofunctional implementations (Raumlabor, 2018). According to design studio Knoll (2020) “the home has become less home, and the office type has vanished. Instead, the work space has changed into a playground where connections are made and interaction is fostered”. This socio-cultural transition creates a shift in the appropriation of space, therefore creating a demand for new types of solutions (Knoll, 2020). This treatise investigates a process of renegotiation of leftover space on Westplein in Utrecht in the Netherlands. The site is an example of ‘terrain vague’ centrally located in the city. The municipality of Utrecht has initiated a temporary intervention on Westplein run by local societies and residents of the neighbourhood Lombok. The aim of this intervention is to generate input from locals through the act of placemaking before the reconstruction of the area into a public park. Furthermore, this intervention also aims to stimulate interaction and connection between local residents as a means to negate the potential for another gentrification process. Therefore, this project is a continuation of temporary activities run by the societies Stichting Perron West, Lucrative Dumpsterdives and Pluktuin. These activities include providing flexible workspace for local residents, collaborative public art workshops, events, concerts, gardening and other activities that connect local artists with residents. This project proposes an ‘architecture a communal and continuous process’ which reflect the needs of the current users, but is capable of being adapted to the technical ability of everyone in order to fulfil the needs of the future users without the creation of waste during its transformation. The proposed typologies, namely citylab and social incubator, aim to create a platform for connection, to stimulate small scale social entrepreneurship that contributes to the creation of a better local urban environment. , Thesis (MArch) -- Faculty of Engineering, the Built Environment and Technology, School of Architecture, 2021
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Date Issued: 2021-12

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Water Struggles and Rural People’s Experiences of Waiting in South Africa’s Eastern Cape Province

- Twalo, Lindani

Authors: Twalo, Lindani
Date: 2021-10
Subjects: Water security , Right to water
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10353/21201 , vital:47394
Description: This study examined water struggles and rural people’s experiences of waiting in South Africa’s Eastern Cape Province. Primarily, it investigated how such struggles connect to people’s experiences of waiting for water services. In essence, the study demonstrates how experiences of waiting are profoundly shaped by subjective meanings that the rural people attach to water at a local level. Thus, the study connects rural water politics to contested meanings over natural resources in South Africa’s communal areas. The empirical analysis in this study goes beyond the largely urban focus in the focus in the politics of waiting – mainly in the informal settlements, slums and other urban peripheries. The study presents some of the less known struggles of rural dwellers, particularly their experiences of waiting for water service provision from the state. South Africa’s Constitution promotes the right to clean water. Despite all the progress made by the democratic government, it is still evident that people in deep rural areas of South Africa are in a very precarious situation when it comes to accessing clean water. The study utilised Auyero (2011) concept of the politics of waiting to examine the poor people’s experiences of waiting for water. The study adopted a case study of Lower Didimana village. The researcher conducted a range of qualitative research techniques – the key informant interviews, focus group discussions, observations and semi-structured interviews. The study found that rural residents of South Africa continue to wait for long periods for water service provision in the current democratic era. Moreover, they are still faced with severe challenges of accessing water; as a result, they are left with no better option but to use traditional ways of retrieving water. It also found that there are strong cultural and spiritual claims that rural dwellers attach to water. To them water is not just only a physiological need which could be addressed through efficient state service – the provision of sufficient tap water. Water is deeply connected in human existence. Just like land, water is a cultural as well as spiritual resource. As such, rural experiences of waiting are not limited to state agency and how the poor experience the state, but are also influences by local struggles over meanings of water. Finally, the study reveals the limitation in state policy on water provision, which is locked in a purely engineering use based paradigm, which mainly strives to address (technically) scarcity of drinking water. However, the findings of this study demonstrates that drinking is just one function of water. Although villagers try to mobilise to engage the state while waiting for water service they articulate other claims that connect to diverse water meanings. Such meanings are barely captured in contemporary literature on rural politics of water. As such, although water is increasing becoming scarce in rural South Africa and the state intervention is increasingly demanded, villagers’ experiences of waiting in Lower Didimana remain strongly connected to what water means to locals. , Thesis (MSoc Sci) (Rural Development) -- University of Fort Hare, 2021
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Date Issued: 2021-10

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The impact of financial inclusion on poverty: a case of selected SADC countries.

- Ndlovu, Nkazimulo Glitter

Authors: Ndlovu, Nkazimulo Glitter
Date: 2021-09
Subjects: Financial services industry , Poverty--Africa , Poverty
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10353/21311 , vital:48393
Description: Financial inclusion is widely regarded as another conduit through which poverty can be alleviated. However, both theoretical and empirical literature does not reach consensus on the effect of financial inclusion on poverty. Against this background, the study empirically examines the effect of financial inclusion on poverty in selected Southern African Development Community (SADC) countries, which include (Botswana, Malawi, Mauritius, Namibia, South Africa, Tanzania, and Zambia). The author employs the Generalized Method of Moments (GMM) technique for the period 1980 to 2019. Based on the Financial Intermediation Theory and the Social Justice Theory: Tunnel effect, 5 different models were estimated. Variables used to capture the different dimensions of financial inclusion include ATMs per 1000km and Bank Accounts per 1000 adults as well as Bank’s private Credit to GDP and Commercial Bank branches per 1000 adults’. The control variables used in the study are; GDP per Capita, Government Consumption, Inflation and Education. Empirical results revealed that financial inclusion reduces the level of poverty in the selected SADC states. The results also revealed that GDP per capita and government spending have a negative effect on poverty in the region. An interesting finding, even though not the major focus of the study was the effect of education. The results revealed that lower levels of education may exacerbate the level of poverty in the region. At the same time, tertiary education was found to have a negative and significant effect on poverty. The empirical results imply that policy makers should center their focus on reforms that will ensure that more people are financially included in the region. Also policies promoting high growth levels and acquisition of higher levels of education should be pursued. , Thesis (MCom) (Economics) -- University of Fort Hare, 2021
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Date Issued: 2021-09

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Rheology behaviour of slurries as a function of particle size and ion concentration

- Kondlo, Princess Kholiwe

Authors: Kondlo, Princess Kholiwe
Date: 2021-04
Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/53333 , vital:45141
Description: In this work, the rheological properties of alumina slurries milled to different particle sizes were investigated. Viscosity increases as the particle size decreases. When increasing amounts of calcium hydroxide, strontium hydroxide or barium hydroxide are added, the viscosity first goes down and then goes up. This can be explained in terms of changes in pH and changes in ionic strength impacting on the surface potential of the particles in suspension. Adding the same concentration of different cations results in different viscosities, with the order being (from high to low viscosity) Ba>Sr>Ca. Effects of partial dissolution of and structural changes to the alumina particles at high pH cannot be excluded. In order to better understanding the different effects, it was attempted to measure the zeta potential of the slurries at different pH values. This resulted in highly positive zeta potential values over the complete pH range, without the observationof an iso-electric point. This does not fit to the observed changes in rheology and contrasts withliterature data. One explanation would be that the measurement system used is unsuitable to yield correct zeta potential values for the materials under investigation. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
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Date Issued: 2021-04

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Evaluating compliance with supply chain management policies in the public sector

- Mvanana, Siziwe

Authors: Mvanana, Siziwe
Date: 2020-04
Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/55064 , vital:49027
Description: Despite reform processes in the employment of Supply Chain Management (SCM) as a strategic tool in the South African public sector, there are predicaments in SCM policies, especially in the public sector. This notwithstanding, research that demystifies the compliance with SCM policies in the public sector. This study evaluate compliance with Supply Chain Management policies in the public sector. The findings of the study revealed that overall the public sector have adopted and implemented the SCM policies. However, SCM policies are sometimes not always aligned with government policies. The most implemented SCM police was demand management, followed by acquisition management. The least implemented policies were logistics, disposal, risk and performance management. No significant differences were observed among the public sector. The public sector face serious SCM challenges in implementing their SCM policies. These challenges stem from: a lack of training for SCM staff, lack of proper capacity, poor planning, and ineffective black economic empowerment in the public sector. Based on the results, there is a need of training for SCM staff, capacity building, better planning interventions, and more effective black economic empowerment. It should be reiterated that the lack of proper SCM policies and procedures are the root cause of problems in service delivery in South Africa. The study concludes by recommending that SCM practitioners should regularly update their SCM policies, ensure proper compliance with the elements of SCM, as well as to source competencies, skills, and knowledge from higher education institutions and private accredited service providers. , Thesis (MPA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2020
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Date Issued: 2020-04

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The role of trade unions in policy formulation: the role of trade unions in policy formulation: The case of the Premier’s Office in the Eastern Cape

- Rula-Peter, Philiswa Nolufefe

Authors: Rula-Peter, Philiswa Nolufefe
Date: 2020-04
Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/55185 , vital:49586
Description: After the first democratic elections of 1994, there was a clear need for radical change in South Africa’s socioeconomic and political order. The new government was confronted by significant institutional transformation and the introduction of new policies in line with the Constitution. It was also necessary to integrate the country into a rapidly changing global environment. Labour relations were important in engineering the much-needed transformation and policy changes. The government based the democratisation of South African society on the principles of equality, non-racialism, and non-sexism (Ferguson, 2013). In line with the Interim Constitution of 1993, new policies and programmes were put in place to improve the quality of life of all people. In the finalised Constitution of 1996, equitable labour relations were formally recognised as a fundamental right, in line with protection provided to all workers in advanced democracies throughout the world (Ferreira, 2005). Before 1994, there was much debate on the issue of labour, with the African National Congress’s (ANC) Members of Parliament (MPs) supporting the extension of the Labour Relations Act (LRA) to the public sector (Macun, cited in Adler, 2000:99). In late 1996, the public sector was included in the LRA, with certain transitional measures. As a result, a few changes took place in the nature of labour relations in the public sector, and there was a shift from consultation to interaction between the state and representative organisations. The first of these changes was the creation of new collective bargaining structures consisting of a central chamber, provincial councils, and departmental structures. Local government had long been unionised and regulated by the LRA. The second change was that labour relations were transferred from the Public Service Commission to the newly established office of the Minister for Public Service and Administration (Ferreira, 2005). , Thesis (MPA) -- Faculty of Humanities, School of Governmental and Social Sciences, 2020
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Date Issued: 2020-04

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Evaluating metabolism-induced toxicity using a non-hepatic cell line

- Weyers, Carli

Authors: Weyers, Carli
Date: 2018
Subjects: Cytochrome P-450 , Drugs Metabolism , Drugs Design
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10962/61950 , vital:28087
Description: The drug discovery pipeline is a complicated process taking roughly 15 years to complete, costing in excess of $1 billion per new chemical entity. It has been estimated that for every 100, 000 promising hit or lead compounds, only one will make it onto the market due to numerous drug candidates being discarded because of many complications. One such complication is metabolism-induced toxicity. Accordingly, an early understanding of the metabolism of any new chemical entity is becoming an integral part of the pipeline. In order to explore this, various methods have been developed including in silico and in vitro techniques. One such method involves performing cell viability assays on human liver cancer cell lines, which overexpress specific metabolic cytochrome P450 enzymes. If a toxic metabolite is produced it would result in reduced cell viability of the transformed cell line in comparison to a control. Since the liver is the primary site of metabolism in the human body, we were curious as to the extent to which background metabolism may play a role in the degree to which toxic metabolites would be produced in these cell lines. The aim of this project, therefore, was to establish if a non-hepatic cell-based system which overexpresses CYP3A4 could be used to detect the metabolism and any subsequent toxicity of compounds which have been reported to be substrates of the CYP450 enzyme. The HEK293 cell line was stably transfected with a plasmid vector for human CYP3A4 to create a model overexpression system for our metabolism studies. The activity of the enzyme was confirmed using the substrate, 7-benzyloxy-4-trifluoromethyl-coumarin. Subsequently, cytotoxicity testing was done on four known pharmaceuticals reported to generate toxic metabolites in hepatic cell-based assays. In silico metabolic predictions on the four known compounds were performed and compared to the results of published literature. Finally, the metabolism of one compound was studied using a combination of high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) in order to detect predicted metabolites. We observed no change in cellular toxicity nor did we detect the formation of metabolites, even though the overexpressed CYP3A4 enzyme was active. The results suggest that caution should be taken when interpreting the results of cell-based metabolism studies, and background metabolism may play a significant role in the data. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2018
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Date Issued: 2018

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