Pedagogical practices teachers use to teach reading lessons in the junior primary phase in Kavango West region’
- Authors: Shimafo, Hildegard
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408762 , vital:70523
- Description: Learning to read for meaning and enjoyment in the Junior Primary phase is an essential goal for every child during their primary schooling. Despite this, reading for meaning and enjoyment in the Namibian context, specifically for primary learners, remains a concern. Current research suggests that there are very few studies that have been done in Namibia that examine the pedagogical practices of Junior Primary teachers to develop learners’ reading competence. In view of that, this study focused on the pedagogical practices of Junior Primary teachers in mediating reading in their classrooms. The study is a qualitative interpretive case study using observation and interviews as tools to generate in-depth data on how teachers teach reading. The study sample comprised of three Junior Primary teachers from Grades 1-3 who participated in this study. The selection criteria were based on historical background and the culture of teaching reading lessons for Grade 1-3 teachers. The study revealed some factors that impede the teaching of reading. Amongst them are a lack of in-service training, language barriers, and the lack of resources. The study found that English used as the LoLT (Language of Learning and Teaching) at the school where the study took place made it difficult for the teachers to convey the correct information to the learners due to a lack of proficiency. The study revealed that this situation limited most of the learners’ reading opportunities. Theory of Practice Architecture (ToPA), in particular by Kemmis and Grootenboer (2008), was used as an explanatory and analytical tool. This research asked the questions: 1.What pedagogical practices do Junior Primary teachers employ to mediate reading? and 2. What factors enable and constrain the pedagogical practices of teachers? As a way forward, this study recommends for a compulsory reading program be instituted at Higher Education Institutions responsible for teacher education. This should empower the teachers to enter a Junior Primary classroom with more confidence to teach the various reading components. This study recommends continuous in-service courses for teachers. The study further recommends that the Ministry of Education, Arts and Culture make provisions for textbooks in all schools for all learners if the learners reading performance is to improve in Namibia. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Shimafo, Hildegard
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408762 , vital:70523
- Description: Learning to read for meaning and enjoyment in the Junior Primary phase is an essential goal for every child during their primary schooling. Despite this, reading for meaning and enjoyment in the Namibian context, specifically for primary learners, remains a concern. Current research suggests that there are very few studies that have been done in Namibia that examine the pedagogical practices of Junior Primary teachers to develop learners’ reading competence. In view of that, this study focused on the pedagogical practices of Junior Primary teachers in mediating reading in their classrooms. The study is a qualitative interpretive case study using observation and interviews as tools to generate in-depth data on how teachers teach reading. The study sample comprised of three Junior Primary teachers from Grades 1-3 who participated in this study. The selection criteria were based on historical background and the culture of teaching reading lessons for Grade 1-3 teachers. The study revealed some factors that impede the teaching of reading. Amongst them are a lack of in-service training, language barriers, and the lack of resources. The study found that English used as the LoLT (Language of Learning and Teaching) at the school where the study took place made it difficult for the teachers to convey the correct information to the learners due to a lack of proficiency. The study revealed that this situation limited most of the learners’ reading opportunities. Theory of Practice Architecture (ToPA), in particular by Kemmis and Grootenboer (2008), was used as an explanatory and analytical tool. This research asked the questions: 1.What pedagogical practices do Junior Primary teachers employ to mediate reading? and 2. What factors enable and constrain the pedagogical practices of teachers? As a way forward, this study recommends for a compulsory reading program be instituted at Higher Education Institutions responsible for teacher education. This should empower the teachers to enter a Junior Primary classroom with more confidence to teach the various reading components. This study recommends continuous in-service courses for teachers. The study further recommends that the Ministry of Education, Arts and Culture make provisions for textbooks in all schools for all learners if the learners reading performance is to improve in Namibia. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-30
Philosophical inquiry into the value of liberal education
- Authors: Wotshela, Siphosihle
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408954 , vital:70540
- Description: Throughout history, scholars have offered numerous conceptions of liberal education, with each scholar providing a slightly and sometimes extremely different idea of what liberal education actually is, what it entails, and what value one stands to gain by partaking in this particular type of education. In this thesis, I inquire into the topic of liberal education in an attempt to clearly understand what value partaking in this type of education offers the contemporary South African. In the process, I offer a defence against what I refer to as the societal context problem—a problem that questions the possibility of a universal benefit that can be obtained by partaking in liberal education. I also offer a comprehensive argument for the preference of Jacob Klein’s conception of liberal education, making the claim that Klein’s conception and the value he identifies with his conception is more convincing than that offered by other scholars because Klein’s conception and the value associated with the conception is universal in a way that allows it to remain relevant even when confronted with the problem of societal context. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Wotshela, Siphosihle
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408954 , vital:70540
- Description: Throughout history, scholars have offered numerous conceptions of liberal education, with each scholar providing a slightly and sometimes extremely different idea of what liberal education actually is, what it entails, and what value one stands to gain by partaking in this particular type of education. In this thesis, I inquire into the topic of liberal education in an attempt to clearly understand what value partaking in this type of education offers the contemporary South African. In the process, I offer a defence against what I refer to as the societal context problem—a problem that questions the possibility of a universal benefit that can be obtained by partaking in liberal education. I also offer a comprehensive argument for the preference of Jacob Klein’s conception of liberal education, making the claim that Klein’s conception and the value he identifies with his conception is more convincing than that offered by other scholars because Klein’s conception and the value associated with the conception is universal in a way that allows it to remain relevant even when confronted with the problem of societal context. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2023
- Full Text:
- Date Issued: 2023-03-30
Saul Msane: friend or foe of the people? The life of the late nineteenth to early twentieth centuries South African politician and journalist
- Authors: Mokoatsi, Thapelo
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/409799 , vital:70631 , DOI 10.21504/10962/409802
- Description: Saul Msane was a prominent founding member of the ANC and an active journalist and editor of the ANC newspaper Abantu-Batho. His career generated controversy. Towards the end of his life, he had a feud with his colleagues in the African National Congress (henceforth Congress) that led to him being labelled isitha sabantu, “the enemy of the people” for his refusal to support the Shilling strike of 1918, an accusation which was retracted a year after his death in 1919. The label of isitha sabantu levelled against Msane, had the effect of ending his political prominence in the Transvaal, forcing him to relocate to kwaNongoma where he died shortly thereafter. Msane’s years in the Congress amounted to about seven years, between 1912, the founding of the Congress, and the demise of his career in 1919. Msane’s seven years in Congress were characterised by controversies, clashes, and conflicts owing to his perceived elitism. In Congress historiography Msane is an obscure and elusive figure, he lives here and there in a footnote, as a supporting statement or a mentioned in mere passing. His marginalisation reveals some of the gaps within the history of Congress and invites us to write about those who did not emerge from the history of Congress necessarily as heroes. This thesis sets out to write a biography of Msane and document his political career beyond that one moment in which he came to be “isitha sabantu”. While Msane’s Congress career was comparably short and filled with tensions, an archive of his life exists. This study is an exploration of that archive to reconstruct the biography of a once prominent leader who dies in political exile from the Congress movement. This thesis sets out to do two key things in relation to reconstructing Msane’s life: Firstly, it reconstructs the longer biography of Msane’s political life by drawing on the existing archives, and thus filling in the South African historical record in that regard. Secondly, at the broader conceptual and historiographical level, it argues that the controversies surrounding Msane’s persona and character illustrate that conceptions of elitism and the nature of being ‘elite’ were key to the politics of Congress at the time. , U-Saul Msane wayengomunye wabasunguli beqembu lika-African National Congress (uKhongolose) futhi eyIntatheli nomhleli wephephandaba i-Abantu-Batho. Umsebenzi ayewenza waba nezingqinamba eziningi ngokwezepolitiki. Ngasekugcineni kwempilo yakhe waba nokungazwani nabaholi ayesebenza nabo kuKhongolose okwadala ukuba abizwe ngesitha sabantu ngenxa yokuba engavumelananga nesiteleka sango-1918 lapho abasebenzi babelwela ukukhushulelwa amaholo. Leligama lokubizwa ngesitha sabantu lahoxiswa ngo 1919 sekudlule unyaka engasekho emhlabeni. Lokubizwa ngesitha sabantu kwalilimaza igama lakhe kwezepolitiki e-Transvaal waze wathutha wayohlala kwaNongoma nokuyilapho ashonela khona. Iminyaka uMsane ayisebenzele uKhongolose yaba isikhombisa, kusukela ekusungulweni kwayo ngo 1912 kuze kufike ekulimaleni komsebenzi wakhe wezepolitiki ngo 1919. Kuleminyaka eyisikhombisa umsebenzi wakhe kuKhongolose wawubhekene nokugxekwa okukhulu nokubukeka njengomuntu onokuzenza ngcono kunabanye abantu. Emlandweni kaKhongolose uMsane akavezwa ngendlela emfanele, kukhulunywa ngaye kudlulwa nje. Lokunganakwa kukaMsane emlandweni kaKhongolose kusiphoqa ukuba sibhale ngabaholi abangaqakanjiswa. Lolucwaningo luveza umlando kaMsane ngokujulile ngaphezu kwangalesikhathi abizwa khona ngesitha sabantu. Noma umsebenzi kaMsane kuKhongolose wabamfushane kunabanye futhi ugcwele izinto kodwa noko ingobo yawo ikhona. Lolucwaningo lucubungula lengobo ukuhlaziya nokubhala kabusha umlando wengqalabutho eyagcina ishonela ngaphandle kombutho kaKhongolose. Loluphando lifisa ukwenza izinto ezimbili: Okokuqala, ibhala kabusha umlando omude wezepolitiki kaMsane kusetshenziswa ulwazi olukhona. Loku kuzosiza ukunothisa umlando wezepolitiki wezwe laseNingizimu Afrika. Okwesibili, ezingeni lobunzululwazi, lolucwaningo luveza ukuthi izinkinga uMsane ahlangabezana nazo zazisukele endleleni okwakubukwa ngayo indaba yokucwasana ngazinga empilo abantu, kwakuyinto ejulile kuKhongolose ukubukeka kwabanye sengathi bazenza ngcono. , Thesis (PhD) -- Faculty of Humanities, History, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Mokoatsi, Thapelo
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/409799 , vital:70631 , DOI 10.21504/10962/409802
- Description: Saul Msane was a prominent founding member of the ANC and an active journalist and editor of the ANC newspaper Abantu-Batho. His career generated controversy. Towards the end of his life, he had a feud with his colleagues in the African National Congress (henceforth Congress) that led to him being labelled isitha sabantu, “the enemy of the people” for his refusal to support the Shilling strike of 1918, an accusation which was retracted a year after his death in 1919. The label of isitha sabantu levelled against Msane, had the effect of ending his political prominence in the Transvaal, forcing him to relocate to kwaNongoma where he died shortly thereafter. Msane’s years in the Congress amounted to about seven years, between 1912, the founding of the Congress, and the demise of his career in 1919. Msane’s seven years in Congress were characterised by controversies, clashes, and conflicts owing to his perceived elitism. In Congress historiography Msane is an obscure and elusive figure, he lives here and there in a footnote, as a supporting statement or a mentioned in mere passing. His marginalisation reveals some of the gaps within the history of Congress and invites us to write about those who did not emerge from the history of Congress necessarily as heroes. This thesis sets out to write a biography of Msane and document his political career beyond that one moment in which he came to be “isitha sabantu”. While Msane’s Congress career was comparably short and filled with tensions, an archive of his life exists. This study is an exploration of that archive to reconstruct the biography of a once prominent leader who dies in political exile from the Congress movement. This thesis sets out to do two key things in relation to reconstructing Msane’s life: Firstly, it reconstructs the longer biography of Msane’s political life by drawing on the existing archives, and thus filling in the South African historical record in that regard. Secondly, at the broader conceptual and historiographical level, it argues that the controversies surrounding Msane’s persona and character illustrate that conceptions of elitism and the nature of being ‘elite’ were key to the politics of Congress at the time. , U-Saul Msane wayengomunye wabasunguli beqembu lika-African National Congress (uKhongolose) futhi eyIntatheli nomhleli wephephandaba i-Abantu-Batho. Umsebenzi ayewenza waba nezingqinamba eziningi ngokwezepolitiki. Ngasekugcineni kwempilo yakhe waba nokungazwani nabaholi ayesebenza nabo kuKhongolose okwadala ukuba abizwe ngesitha sabantu ngenxa yokuba engavumelananga nesiteleka sango-1918 lapho abasebenzi babelwela ukukhushulelwa amaholo. Leligama lokubizwa ngesitha sabantu lahoxiswa ngo 1919 sekudlule unyaka engasekho emhlabeni. Lokubizwa ngesitha sabantu kwalilimaza igama lakhe kwezepolitiki e-Transvaal waze wathutha wayohlala kwaNongoma nokuyilapho ashonela khona. Iminyaka uMsane ayisebenzele uKhongolose yaba isikhombisa, kusukela ekusungulweni kwayo ngo 1912 kuze kufike ekulimaleni komsebenzi wakhe wezepolitiki ngo 1919. Kuleminyaka eyisikhombisa umsebenzi wakhe kuKhongolose wawubhekene nokugxekwa okukhulu nokubukeka njengomuntu onokuzenza ngcono kunabanye abantu. Emlandweni kaKhongolose uMsane akavezwa ngendlela emfanele, kukhulunywa ngaye kudlulwa nje. Lokunganakwa kukaMsane emlandweni kaKhongolose kusiphoqa ukuba sibhale ngabaholi abangaqakanjiswa. Lolucwaningo luveza umlando kaMsane ngokujulile ngaphezu kwangalesikhathi abizwa khona ngesitha sabantu. Noma umsebenzi kaMsane kuKhongolose wabamfushane kunabanye futhi ugcwele izinto kodwa noko ingobo yawo ikhona. Lolucwaningo lucubungula lengobo ukuhlaziya nokubhala kabusha umlando wengqalabutho eyagcina ishonela ngaphandle kombutho kaKhongolose. Loluphando lifisa ukwenza izinto ezimbili: Okokuqala, ibhala kabusha umlando omude wezepolitiki kaMsane kusetshenziswa ulwazi olukhona. Loku kuzosiza ukunothisa umlando wezepolitiki wezwe laseNingizimu Afrika. Okwesibili, ezingeni lobunzululwazi, lolucwaningo luveza ukuthi izinkinga uMsane ahlangabezana nazo zazisukele endleleni okwakubukwa ngayo indaba yokucwasana ngazinga empilo abantu, kwakuyinto ejulile kuKhongolose ukubukeka kwabanye sengathi bazenza ngcono. , Thesis (PhD) -- Faculty of Humanities, History, 2023
- Full Text:
- Date Issued: 2023-03-30
South African traditional healers’ perceptions and treatment of the symptoms of depression
- Authors: Augustine, Daniella Joan
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408789 , vital:70525
- Description: While depression is experienced worldwide, the World Health Organization indicated that over 80% of this disease burden is found in low- and middle-income countries, with 16% of depressive disorder cases being found in Africa. Specifically, in South Africa, the lifetime prevalence of major depressive disorder is 9.7%. Research conducted on traditional healing estimates that as high as 80% of black individuals in South Africa choose to consult traditional healers. Although there was initial consensus that the use of traditional healers reflected a lack of access to alternative resources, more recent research has however indicated that traditional healers are consulted even when psychiatric facilities and medication are available. Research has illustrated that many patients that chose to consult traditional healers do so as a result of their shared beliefs, and traditional healers' ability to understand the cultural frameworks underlying illness. The current study investigated how traditional healers in the Eastern Cape perceive and treat phenomena currently understood as the symptoms of depression and how these understandings can be incorporated into collaborations between Western medicine and traditional healing practice. A qualitative research design was used to examine the perspectives and treatment methods of isiXhosa traditional healers in the Eastern Cape. Four healers participated in the study. Key findings indicated that there is no single cause or definition of the phenomenon of depression by healers. Causality is greatly attributed to spiritual causes and ancestors play a key role in guiding the diagnosis and multiple treatment interventions employed by healers to treat the experience of depression. Finally, all traditional healers expressed a willingness to collaborate and work with the Western healthcare system, however, they indicated a strong need for greater recognition as a valid healthcare system. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Augustine, Daniella Joan
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408789 , vital:70525
- Description: While depression is experienced worldwide, the World Health Organization indicated that over 80% of this disease burden is found in low- and middle-income countries, with 16% of depressive disorder cases being found in Africa. Specifically, in South Africa, the lifetime prevalence of major depressive disorder is 9.7%. Research conducted on traditional healing estimates that as high as 80% of black individuals in South Africa choose to consult traditional healers. Although there was initial consensus that the use of traditional healers reflected a lack of access to alternative resources, more recent research has however indicated that traditional healers are consulted even when psychiatric facilities and medication are available. Research has illustrated that many patients that chose to consult traditional healers do so as a result of their shared beliefs, and traditional healers' ability to understand the cultural frameworks underlying illness. The current study investigated how traditional healers in the Eastern Cape perceive and treat phenomena currently understood as the symptoms of depression and how these understandings can be incorporated into collaborations between Western medicine and traditional healing practice. A qualitative research design was used to examine the perspectives and treatment methods of isiXhosa traditional healers in the Eastern Cape. Four healers participated in the study. Key findings indicated that there is no single cause or definition of the phenomenon of depression by healers. Causality is greatly attributed to spiritual causes and ancestors play a key role in guiding the diagnosis and multiple treatment interventions employed by healers to treat the experience of depression. Finally, all traditional healers expressed a willingness to collaborate and work with the Western healthcare system, however, they indicated a strong need for greater recognition as a valid healthcare system. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
The effectiveness and feasibility of online prolonged exposure therapy for post-traumatic stress among university students
- Authors: Slabbert, Maryna
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408885 , vital:70534
- Description: Research has found that 70.6% of university students reported exposure to several traumatic events (Hoffman, 2002). Considering the high prevalence of trauma exposure among South African university students, many are at risk of developing post-traumatic stress disorder (PTSD) (Iribarren, Prolo, Naegos & Chiappelli, 2005). Prolonged Exposure Therapy (PE) is regarded as a first-line trauma therapy for PTSD (Foa, Hembree, Rothbaum, & Rauch, 2019). During the Covid-19 pandemic, public health guidelines for physical distancing reduced access to face-to-face mental health care. In response to this, many health care providers adapted to pandemic constraints by meeting their clients online, through Zoom, for example (Wells et al., 2020). Considering the prevalence of trauma exposure among university students, as well as the increased necessity of teletherapy, the study aimed to investigate the effectiveness and feasibility of online PE for PTSD among university students in a South African setting. The study employed Single-Case Experimental Design (SCED) as basis for its research design. Participants included a sample of Rhodes University students (n = 3) who were recruited through purposive sampling. Prior to the intervention, all three participants met the criteria for PTSD, and comorbid depression. Based on the measures used, two of the three participants did not meet the criteria for PTSD post-intervention. In terms of depression symptoms, one participant did not meet the criteria for depression post-intervention, and another participant showed a decrease in depression symptoms. Regarding the feasibility of online PE, all three participants reported the intervention to be feasible, acceptable, and appropriate. Overall, the study provides preliminary results to support the effectiveness and feasibility of online PE. It also gives insight into the value of intervention research and how it can ameliorate PTSD in a South African setting, as well as other low- and middle-income countries (LMICs). , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Slabbert, Maryna
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408885 , vital:70534
- Description: Research has found that 70.6% of university students reported exposure to several traumatic events (Hoffman, 2002). Considering the high prevalence of trauma exposure among South African university students, many are at risk of developing post-traumatic stress disorder (PTSD) (Iribarren, Prolo, Naegos & Chiappelli, 2005). Prolonged Exposure Therapy (PE) is regarded as a first-line trauma therapy for PTSD (Foa, Hembree, Rothbaum, & Rauch, 2019). During the Covid-19 pandemic, public health guidelines for physical distancing reduced access to face-to-face mental health care. In response to this, many health care providers adapted to pandemic constraints by meeting their clients online, through Zoom, for example (Wells et al., 2020). Considering the prevalence of trauma exposure among university students, as well as the increased necessity of teletherapy, the study aimed to investigate the effectiveness and feasibility of online PE for PTSD among university students in a South African setting. The study employed Single-Case Experimental Design (SCED) as basis for its research design. Participants included a sample of Rhodes University students (n = 3) who were recruited through purposive sampling. Prior to the intervention, all three participants met the criteria for PTSD, and comorbid depression. Based on the measures used, two of the three participants did not meet the criteria for PTSD post-intervention. In terms of depression symptoms, one participant did not meet the criteria for depression post-intervention, and another participant showed a decrease in depression symptoms. Regarding the feasibility of online PE, all three participants reported the intervention to be feasible, acceptable, and appropriate. Overall, the study provides preliminary results to support the effectiveness and feasibility of online PE. It also gives insight into the value of intervention research and how it can ameliorate PTSD in a South African setting, as well as other low- and middle-income countries (LMICs). , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
The use of lesson study to assist junior primary ‘in-service training teachers’ to develop learners’ number sense using number talks
- Authors: Ortman-Gaweseb, Dominika
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408750 , vital:70522
- Description: Thesis embargoed. To be released in 2025. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Ortman-Gaweseb, Dominika
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408750 , vital:70522
- Description: Thesis embargoed. To be released in 2025. , Thesis (MEd) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-30
Which Black Lives matter? : a decolonial interrogation of xenophobia on Black South African Twitter
- Authors: McBrown, Anima
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408930 , vital:70538
- Description: Thesis embargoed. To be released in 2025. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: McBrown, Anima
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408930 , vital:70538
- Description: Thesis embargoed. To be released in 2025. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2023
- Full Text:
- Date Issued: 2023-03-30
“It’s not just me on a video call with someone…” Students’ experiences of a forced transition from face-to-face psychotherapy to online psychotherapy during COVID-19: an interpretative phenomenological analysis
- Authors: Keet, Nicole Tahnee
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408845 , vital:70531
- Description: The aim of this study is to explore university students’ experience of a forced transition from face-to-face therapy to online therapy during COVID-19. This pandemic was unexpected and affected all areas of life, including the closure of universities, which left therapists and clients alike unsure of how to navigate these unchartered territories. Although there is a considerable amount of international research on experiences of online therapy, there is little research on a forced transition to online therapy because of COVID-19 and even less within the South African context. A sample of six participants between the ages of 20 and 30 years old were selected through purposive and convenience sampling. Semi-structured interviews were conducted, and interpretative Phenomenological Analysis (IPA) was utilised to ascertain how participants make sense of their worlds in relation to the transition to online therapy. The analysis provided three main superordinate themes, which are supported by subordinate themes. The superordinate themes are: 1) Online therapy as authentic and continuous, where the participants experienced the comfort and convenience of online therapy, the continuity of care and the anonymity of online therapy. 2) Online therapy as disruptive and invasive, where participants experienced issues with privacy, an intrusive environment, technological challenges, lack of body language and therapy feeling more disposable. 3) Getting used to online therapy with some help from the therapist, where participants felt an adjustment period was necessary as well as transparency and containment from the therapist to help with the transition. These findings support some existing South African literature; however, it also engages with findings unique to this study, that will hopefully be used for further exploration. The study ends with recommendations for training therapists on using online therapy. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
- Authors: Keet, Nicole Tahnee
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408845 , vital:70531
- Description: The aim of this study is to explore university students’ experience of a forced transition from face-to-face therapy to online therapy during COVID-19. This pandemic was unexpected and affected all areas of life, including the closure of universities, which left therapists and clients alike unsure of how to navigate these unchartered territories. Although there is a considerable amount of international research on experiences of online therapy, there is little research on a forced transition to online therapy because of COVID-19 and even less within the South African context. A sample of six participants between the ages of 20 and 30 years old were selected through purposive and convenience sampling. Semi-structured interviews were conducted, and interpretative Phenomenological Analysis (IPA) was utilised to ascertain how participants make sense of their worlds in relation to the transition to online therapy. The analysis provided three main superordinate themes, which are supported by subordinate themes. The superordinate themes are: 1) Online therapy as authentic and continuous, where the participants experienced the comfort and convenience of online therapy, the continuity of care and the anonymity of online therapy. 2) Online therapy as disruptive and invasive, where participants experienced issues with privacy, an intrusive environment, technological challenges, lack of body language and therapy feeling more disposable. 3) Getting used to online therapy with some help from the therapist, where participants felt an adjustment period was necessary as well as transparency and containment from the therapist to help with the transition. These findings support some existing South African literature; however, it also engages with findings unique to this study, that will hopefully be used for further exploration. The study ends with recommendations for training therapists on using online therapy. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-03-30
A Comparison of Mitochondrial Heat Shock Protein 70 and Hsp70 Escort Protein 1 Orthologues from Trypanosoma brucei and Homo sapiens
- Authors: Hand, Francis Bryan
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422281 , vital:71927
- Description: The causative agent of African trypanosomiasis, Trypanosoma brucei (T. brucei), has an expanded retinue of specialized heat shock proteins, which have been identified as crucial to the progression of the disease. These play a central role in disease progression and transmission through their involvement in cell-cycle pathways which bring about cell-cycle arrest and differentiation. Hsp70 proteins are essential for the maintenance of proteostasis in the cell. Mitochondrial Hsp70 (mtHsp70) is a highly conserved molecular chaperone required for both the translocation of nuclear encoded proteins across the two mitochondrial membranes and the subsequent folding of proteins in the matrix. The T. brucei genome encodes three copies of mtHsp70 which are 100% identical. MtHsp70 self-aggregates, a property unique to this isoform, and an Hsp70 escort protein (Hep1) is required to maintain the molecular chaperone in a soluble, functional state. This study aimed to compare the solubilizing interaction of Hep1 from T. brucei and Homo sapiens (H. sapien). The recently introduced Alphafold program was used to analyze the structures of mtHsp70 and Hep1 proteins and allowed observations of structures unavailable to other modelling techniques. The GVFEV motif found in the ATPase domain of mtHsp70s interacted with the linker region, resulting in aggregation, the Alphafold models produced indicated that the replacement of the lysine (K) residue within the KTFEV motif of DnaK (prokaryotic Hsp70) with Glycine (G), may abrogate bond formation between the motif and a region between lobe I and II of the ATPase domain. This may facilitate the aggregation reaction of mtHsp70 orthologues and provides a residue of interest for future studies. Both TbHep1 and HsHep1 reduced the thermal aggregation of TbmtHsp70 and mortalin (H. sapien mtHsp70) respectively, however, TbHep1 was ~ 15 % less effective than HsHep1 at higher concentrations (4 uM). TbHep1 itself appeared to be aggregation-prone when under conditions of thermal stress, Alphafold models suggest this may be due to an N-terminal α- helical structure not present in HsHep1. These results indicate that TbHep1 is functionally similar to HsHep1, however, the orthologue may operate in a unique manner which requires further investigation. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Hand, Francis Bryan
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422281 , vital:71927
- Description: The causative agent of African trypanosomiasis, Trypanosoma brucei (T. brucei), has an expanded retinue of specialized heat shock proteins, which have been identified as crucial to the progression of the disease. These play a central role in disease progression and transmission through their involvement in cell-cycle pathways which bring about cell-cycle arrest and differentiation. Hsp70 proteins are essential for the maintenance of proteostasis in the cell. Mitochondrial Hsp70 (mtHsp70) is a highly conserved molecular chaperone required for both the translocation of nuclear encoded proteins across the two mitochondrial membranes and the subsequent folding of proteins in the matrix. The T. brucei genome encodes three copies of mtHsp70 which are 100% identical. MtHsp70 self-aggregates, a property unique to this isoform, and an Hsp70 escort protein (Hep1) is required to maintain the molecular chaperone in a soluble, functional state. This study aimed to compare the solubilizing interaction of Hep1 from T. brucei and Homo sapiens (H. sapien). The recently introduced Alphafold program was used to analyze the structures of mtHsp70 and Hep1 proteins and allowed observations of structures unavailable to other modelling techniques. The GVFEV motif found in the ATPase domain of mtHsp70s interacted with the linker region, resulting in aggregation, the Alphafold models produced indicated that the replacement of the lysine (K) residue within the KTFEV motif of DnaK (prokaryotic Hsp70) with Glycine (G), may abrogate bond formation between the motif and a region between lobe I and II of the ATPase domain. This may facilitate the aggregation reaction of mtHsp70 orthologues and provides a residue of interest for future studies. Both TbHep1 and HsHep1 reduced the thermal aggregation of TbmtHsp70 and mortalin (H. sapien mtHsp70) respectively, however, TbHep1 was ~ 15 % less effective than HsHep1 at higher concentrations (4 uM). TbHep1 itself appeared to be aggregation-prone when under conditions of thermal stress, Alphafold models suggest this may be due to an N-terminal α- helical structure not present in HsHep1. These results indicate that TbHep1 is functionally similar to HsHep1, however, the orthologue may operate in a unique manner which requires further investigation. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-03-29
A Pedagogy of Love: reflections on 25 years of informal vocational education and training practices in the commercial fishing industry in South Africa
- Authors: Ferguson, Robin Anne
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366189 , vital:65841 , DOI https://doi.org/10.21504/10962/366189
- Description: This thesis is a reflection of informal vocational education and training (IVET) practices conducted by the Researcher in the commercial fishing industry between 1995-2021. Fourteen interventions took place during this time which involved several hundred sea-going employees who are disadvantaged by low levels of literacies and low/no Internet Computer Technology connectivity. The Production Programme was chosen as the focus of study and draws upon the influence of the other thirteen programmes. The purpose of the Production Programme was to teach technical fish processing skills to the production management teams and factory hands who work in the factories on board the vessels. The programme ran for five years and evolved through three distinct generations. At the heart of this work lies the question: ‘What made these programmes successful?’ This is an intra-programmatic study and seeks to identify the pedagogical practices which promoted or confounded the efficacy of the Production Programme; and based upon this understanding how such programmes could be improved, transferred, and taken to scale. These questions are both descriptive and explorative in nature. IVET is regarded as training which takes place outside of the formal South African National Qualifications Framework. This work is relevant because approximately 80% of sea-going staff neither finish school, nor get the opportunity of Post School Education and Training by going to a university, a technical institution, or a community college. This statistic is reflected in the general population (Department of Higher Education and Training [DHET], 2022). There is a fine line between being employed and unemployed for people working at this level in the formal economy which makes this project relevant to youth or persons who are ‘not in employment, education or training’ too. This means that for most South African adults IVET presents a significant opportunity for post-school education. Therefore, it is important to answer the questions raised above to rapidly improve inclusion of the majority of South Africans into meaningful education which improves livelihoods. The Theory of Practice Architectures (TPA), from the collection of social-material practice theories, is the conceptual framework for this thesis. The smallest unit of analysis of TPA are practices which may be ‘sayings/thinkings’, ‘doings’, or ‘relatings’. These practices bundle together into practice arrangements and form practice architectures. The reason that TPA was chosen was that practices were the only data available as we (learners, managers, facilitators, and me) knew what we had said/thought or done, and we were aware of the relationships between us over the years as the fourteen interventions played out. Under conventional research circumstances data would be collected in real time, however in this project, most of the data is historical. In addition to the fundamental building blocks of TPA, the theory is embedded in a Theory of Education. There have also been contemporary enhancements to the TPA which were significant to this study, for example, the Ecologies of Practices, a Trellis of Practices which Support Professional Learning, Middle Leadership, Travelling Practices, and moves towards transformative or transgressive education using the TPA in IVET. This is empirical, qualitative research and an ethnographic case study was chosen as the research design which is a methodology particularly suited to answering both descriptive and explorative questions. Nine methods for data collection were used, namely an historical reflective narrative; two focused-group interviews; three individual interviews; four Whatsapp videos; one WhatsApp voice note; two mobisodes; ten questionnaires; 29 documents; and 16 photographs. Because this data was collected under Covid-19 pandemic conditions, two conceptions were employed to guide the generation of data under these uncertain and constrained conditions. These were firstly, the ‘methodology of chance’ which allowed for a ‘methodological agility’; and secondly, the idea of ‘information power’ which is helpful in deciding on how much data is enough. In order to be explicit concerning a key research activity, the approach and method used to review the literature is explicated. Key practices were identified in the data set and described; and then the data was analysed using heuristics provided by TPA theorists. Seven Tables of Invention were used to synthesise the data arising from these practices. An eighth Table of Invention was used to synthesise all the practices and practice arrangements characterised; and to indicate how these evolved over time and space. The data description and analysis is supported by eight Analytic Memos, a comprehensive Data Code Table and a hyperlink to a data repository which provides access to oral and video material. The findings distinguished five key practices and practice arrangements which were: Practices of the Creation of Courseware; Practices of Teaching and Learning; Practices of Assessment; Practices of Love; Practices of Management. The thesis title is reflective of the impact which love has upon the pedagogical process of IVET. Based upon the analysis and synthesis of the corpus of data, practices which either promoted or confounded the Production Programme became visible; it is these insights which inform future improvements to similar programmes. Emanating from these findings, two overarching practice architectures (PA) were identified which restrained the Production Programme in the same manner that the banks of a river restrain a river, and yet simultaneously, are changed by the river over time. These are the PA of Methodology and Methods and the PA of Maturing Ecologies of Practices. The inferences drawn from the data were achieved through the use of deductive, inductive, and abductive reasoning. My claim to new knowledge is a lamination of a practical contribution on one side of the coin, and a theoretical contribution on the other side of the coin. The PA of Methodology and Methods provides a practical mechanism to create, deliver and assess IVET. This is done by explicating the three practice architectures which constitute the overarching PA of Methodology and Methods which are, the PA of Informality; the PA of Range, and the PA of Relationality. An IVET programme constitutes Ecologies of Practices. The theoretical conception of the overarching PA of Maturing Ecologies of Practices provides a conceptual tool which enables the transferring and scaling of IVET programmes. It does this by providing theoretical indicators to establish the ‘state’ of an IVET programme as it matures over time from a pioneer state to a settler state. An IVET educator can then work towards creating a PA which is conducive for a mature ecologies of practices to form; and the programme can then be transferred and/or taken to scale, if this is desirable in the particular context. The power of my claim to new knowledge does not lie on one side or the other of the coin, but in the lamination of the practical and theoretical contributions put to use in the service of IVET. This thesis concludes with a number of theoretical and practical recommendations which are loosely grouped according to ‘sayings/thinkings’, ‘doings’ and ‘relatings’ in deference to the value of TPA to this thesis. An urgency is conveyed in these recommendations as there is an immediate need to improve the livelihoods of ordinary South Africans. One of the ways of doing this is through informal ‘education for living well’ which contributes to a ‘world worth living in’. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Ferguson, Robin Anne
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366189 , vital:65841 , DOI https://doi.org/10.21504/10962/366189
- Description: This thesis is a reflection of informal vocational education and training (IVET) practices conducted by the Researcher in the commercial fishing industry between 1995-2021. Fourteen interventions took place during this time which involved several hundred sea-going employees who are disadvantaged by low levels of literacies and low/no Internet Computer Technology connectivity. The Production Programme was chosen as the focus of study and draws upon the influence of the other thirteen programmes. The purpose of the Production Programme was to teach technical fish processing skills to the production management teams and factory hands who work in the factories on board the vessels. The programme ran for five years and evolved through three distinct generations. At the heart of this work lies the question: ‘What made these programmes successful?’ This is an intra-programmatic study and seeks to identify the pedagogical practices which promoted or confounded the efficacy of the Production Programme; and based upon this understanding how such programmes could be improved, transferred, and taken to scale. These questions are both descriptive and explorative in nature. IVET is regarded as training which takes place outside of the formal South African National Qualifications Framework. This work is relevant because approximately 80% of sea-going staff neither finish school, nor get the opportunity of Post School Education and Training by going to a university, a technical institution, or a community college. This statistic is reflected in the general population (Department of Higher Education and Training [DHET], 2022). There is a fine line between being employed and unemployed for people working at this level in the formal economy which makes this project relevant to youth or persons who are ‘not in employment, education or training’ too. This means that for most South African adults IVET presents a significant opportunity for post-school education. Therefore, it is important to answer the questions raised above to rapidly improve inclusion of the majority of South Africans into meaningful education which improves livelihoods. The Theory of Practice Architectures (TPA), from the collection of social-material practice theories, is the conceptual framework for this thesis. The smallest unit of analysis of TPA are practices which may be ‘sayings/thinkings’, ‘doings’, or ‘relatings’. These practices bundle together into practice arrangements and form practice architectures. The reason that TPA was chosen was that practices were the only data available as we (learners, managers, facilitators, and me) knew what we had said/thought or done, and we were aware of the relationships between us over the years as the fourteen interventions played out. Under conventional research circumstances data would be collected in real time, however in this project, most of the data is historical. In addition to the fundamental building blocks of TPA, the theory is embedded in a Theory of Education. There have also been contemporary enhancements to the TPA which were significant to this study, for example, the Ecologies of Practices, a Trellis of Practices which Support Professional Learning, Middle Leadership, Travelling Practices, and moves towards transformative or transgressive education using the TPA in IVET. This is empirical, qualitative research and an ethnographic case study was chosen as the research design which is a methodology particularly suited to answering both descriptive and explorative questions. Nine methods for data collection were used, namely an historical reflective narrative; two focused-group interviews; three individual interviews; four Whatsapp videos; one WhatsApp voice note; two mobisodes; ten questionnaires; 29 documents; and 16 photographs. Because this data was collected under Covid-19 pandemic conditions, two conceptions were employed to guide the generation of data under these uncertain and constrained conditions. These were firstly, the ‘methodology of chance’ which allowed for a ‘methodological agility’; and secondly, the idea of ‘information power’ which is helpful in deciding on how much data is enough. In order to be explicit concerning a key research activity, the approach and method used to review the literature is explicated. Key practices were identified in the data set and described; and then the data was analysed using heuristics provided by TPA theorists. Seven Tables of Invention were used to synthesise the data arising from these practices. An eighth Table of Invention was used to synthesise all the practices and practice arrangements characterised; and to indicate how these evolved over time and space. The data description and analysis is supported by eight Analytic Memos, a comprehensive Data Code Table and a hyperlink to a data repository which provides access to oral and video material. The findings distinguished five key practices and practice arrangements which were: Practices of the Creation of Courseware; Practices of Teaching and Learning; Practices of Assessment; Practices of Love; Practices of Management. The thesis title is reflective of the impact which love has upon the pedagogical process of IVET. Based upon the analysis and synthesis of the corpus of data, practices which either promoted or confounded the Production Programme became visible; it is these insights which inform future improvements to similar programmes. Emanating from these findings, two overarching practice architectures (PA) were identified which restrained the Production Programme in the same manner that the banks of a river restrain a river, and yet simultaneously, are changed by the river over time. These are the PA of Methodology and Methods and the PA of Maturing Ecologies of Practices. The inferences drawn from the data were achieved through the use of deductive, inductive, and abductive reasoning. My claim to new knowledge is a lamination of a practical contribution on one side of the coin, and a theoretical contribution on the other side of the coin. The PA of Methodology and Methods provides a practical mechanism to create, deliver and assess IVET. This is done by explicating the three practice architectures which constitute the overarching PA of Methodology and Methods which are, the PA of Informality; the PA of Range, and the PA of Relationality. An IVET programme constitutes Ecologies of Practices. The theoretical conception of the overarching PA of Maturing Ecologies of Practices provides a conceptual tool which enables the transferring and scaling of IVET programmes. It does this by providing theoretical indicators to establish the ‘state’ of an IVET programme as it matures over time from a pioneer state to a settler state. An IVET educator can then work towards creating a PA which is conducive for a mature ecologies of practices to form; and the programme can then be transferred and/or taken to scale, if this is desirable in the particular context. The power of my claim to new knowledge does not lie on one side or the other of the coin, but in the lamination of the practical and theoretical contributions put to use in the service of IVET. This thesis concludes with a number of theoretical and practical recommendations which are loosely grouped according to ‘sayings/thinkings’, ‘doings’ and ‘relatings’ in deference to the value of TPA to this thesis. An urgency is conveyed in these recommendations as there is an immediate need to improve the livelihoods of ordinary South Africans. One of the ways of doing this is through informal ‘education for living well’ which contributes to a ‘world worth living in’. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
An in vitro investigation of novel quinolone derivatives on selected pharmacological targets for diabetes mellitus and associated complications
- Authors: Ayodele, Omobolanle Opeyemi
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/409813 , vital:70632
- Description: Diabetes mellitus (DM) is a group of endocrine and metabolic disorders characterised and identified by the presence of hyperglycaemia over a long period and, to an extent, accompanied by hyperlipidaemia. CVD has been reported to be the leading cause of mortality in patients with DM. Several antidiabetic agents are available for managing DM, but these agents are not for curative therapy and present with undesirable side effects. In addition, these agents become less effective as the patient's condition progresses to complete beta-cell failure. Therefore, developing newer antidiabetic agents with minimal undesirable side effects, prolonged efficacy and protection against the development of DM complications are necessary. This study was conducted to identify potential novel antidiabetic agents with cardiovascular-protective activity. The compounds of interest for the study were quinolone derivatives since quinolones have been reported to have an antihyperglycaemic effect. , Thesis (MSc) -- Faculty of Pharmacy, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Ayodele, Omobolanle Opeyemi
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/409813 , vital:70632
- Description: Diabetes mellitus (DM) is a group of endocrine and metabolic disorders characterised and identified by the presence of hyperglycaemia over a long period and, to an extent, accompanied by hyperlipidaemia. CVD has been reported to be the leading cause of mortality in patients with DM. Several antidiabetic agents are available for managing DM, but these agents are not for curative therapy and present with undesirable side effects. In addition, these agents become less effective as the patient's condition progresses to complete beta-cell failure. Therefore, developing newer antidiabetic agents with minimal undesirable side effects, prolonged efficacy and protection against the development of DM complications are necessary. This study was conducted to identify potential novel antidiabetic agents with cardiovascular-protective activity. The compounds of interest for the study were quinolone derivatives since quinolones have been reported to have an antihyperglycaemic effect. , Thesis (MSc) -- Faculty of Pharmacy, 2023
- Full Text:
- Date Issued: 2023-03-29
An in-depth investigation of an early literacy intervention in Grade R in the Eastern Cape Province, South Africa
- Authors: Hodgskiss, Jennifer Adelé
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366222 , vital:65844
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Hodgskiss, Jennifer Adelé
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366222 , vital:65844
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- 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
- Full Text:
- Date Issued: 2023-03-29
- 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
- Full Text:
- Date Issued: 2023-03-29
Biological longitudinal aspects of the Kabompo River, a significant tributary of the upper Zambezi sub-catchment, North-west Province, Zambia
- Janse van Rensburg, Lomarie Cathleen
- Authors: Janse van Rensburg, Lomarie Cathleen
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422292 , vital:71928
- Description: The landscape of the Upper Zambezi Catchment in the remote North-Western Province of Zambia retains many natural features, but current and future anthropogenic activities threaten its integrity. Lack of information relating to the basic ecological functioning of the region hampers conservation efforts. Flooding from the adjacent woody-savanna and open grasslands in the Upper-Zambezi Catchment in the wet season drives crucial processes in the aquatic ecosystems such as the Kabompo River. This thesis describes aquatic food webs and describes the nutrient cycling in this river. A general introduction was based on the seasonality, river morphology, and biodiversity of the Kabompo River. There is no aquatic food web information available on this river. To address this knowledge gap, sampling of the principal food web components– vegetation, invertebrates, and fish – were collected in the dry season from August to September 2019 across six sites in the Kabompo River. Stable isotope analyses provided proxies for the food web structure at each site, and were the basis of longitudinal comparisons. The analyses suggest that the Kabompo River food webs follow the trophic ordination and nutrient cycling characteristic of the revised-Riverine Productivity Model. Food webs and community assemblages remain structurally similar between sites and provide some evidence of bottom-up productivity-driven trophic dynamics. To predict the possible landscape-scale processing of nutrient changes present for the aquatic ecosystems of the Kabompo River, a longitudinal comparison between a herbivore, Labeo cylindricus, and omnivore, Synodontis spp., fish species and their resources (primary producers and invertebrates) was done and showed archetypal fish food web trophic separation (2 ‰ to3 ‰) between species which remains consistent for the headwater sites. The nutrient values change at the convergence between the Kabompo Bridge and the Mwinilunga branches and show a decrease in the trophic separation of the sites below. This change becomes apparent from the last site, Watopa, where the trophic separation re-establishes (2 ‰ to 3 ‰) between the species. The trend suggests primarily autochthonous production in the headwater reaches, changing to allochthonous and autochthonous nutrient incorporation after the convergence of the two main branches. Permanent wetlands surrounding the convergence zones may be conducive to more primary producer activity and increased nutrient turnover. Permanent wetlands are a common feature of the Upper Zambezi Catchment tributaries, with the most notable lentic system the Barotse Flood Plains in the south, which shares reach-adjacent characteristics with the Kabompo River. Trends from the 2015 dry season identified for the Barotse Flood Plains support the findings of this thesis, where the δ13C values recorded reach depletion of -45 ‰. Management in the Upper Zambezi Basin and the Kabompo River comprises biannual assessments of water quality and quantity by the Zambezi River Authority, but not of the ecosystem process. This thesis may provide information to address the ecological (food webs and nutrient cycling) dynamics of the Basin rivers. As the first baseline information on the river's biology and ecology, it may present a comparative basis for future assessments under conservation management strategies. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Janse van Rensburg, Lomarie Cathleen
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422292 , vital:71928
- Description: The landscape of the Upper Zambezi Catchment in the remote North-Western Province of Zambia retains many natural features, but current and future anthropogenic activities threaten its integrity. Lack of information relating to the basic ecological functioning of the region hampers conservation efforts. Flooding from the adjacent woody-savanna and open grasslands in the Upper-Zambezi Catchment in the wet season drives crucial processes in the aquatic ecosystems such as the Kabompo River. This thesis describes aquatic food webs and describes the nutrient cycling in this river. A general introduction was based on the seasonality, river morphology, and biodiversity of the Kabompo River. There is no aquatic food web information available on this river. To address this knowledge gap, sampling of the principal food web components– vegetation, invertebrates, and fish – were collected in the dry season from August to September 2019 across six sites in the Kabompo River. Stable isotope analyses provided proxies for the food web structure at each site, and were the basis of longitudinal comparisons. The analyses suggest that the Kabompo River food webs follow the trophic ordination and nutrient cycling characteristic of the revised-Riverine Productivity Model. Food webs and community assemblages remain structurally similar between sites and provide some evidence of bottom-up productivity-driven trophic dynamics. To predict the possible landscape-scale processing of nutrient changes present for the aquatic ecosystems of the Kabompo River, a longitudinal comparison between a herbivore, Labeo cylindricus, and omnivore, Synodontis spp., fish species and their resources (primary producers and invertebrates) was done and showed archetypal fish food web trophic separation (2 ‰ to3 ‰) between species which remains consistent for the headwater sites. The nutrient values change at the convergence between the Kabompo Bridge and the Mwinilunga branches and show a decrease in the trophic separation of the sites below. This change becomes apparent from the last site, Watopa, where the trophic separation re-establishes (2 ‰ to 3 ‰) between the species. The trend suggests primarily autochthonous production in the headwater reaches, changing to allochthonous and autochthonous nutrient incorporation after the convergence of the two main branches. Permanent wetlands surrounding the convergence zones may be conducive to more primary producer activity and increased nutrient turnover. Permanent wetlands are a common feature of the Upper Zambezi Catchment tributaries, with the most notable lentic system the Barotse Flood Plains in the south, which shares reach-adjacent characteristics with the Kabompo River. Trends from the 2015 dry season identified for the Barotse Flood Plains support the findings of this thesis, where the δ13C values recorded reach depletion of -45 ‰. Management in the Upper Zambezi Basin and the Kabompo River comprises biannual assessments of water quality and quantity by the Zambezi River Authority, but not of the ecosystem process. This thesis may provide information to address the ecological (food webs and nutrient cycling) dynamics of the Basin rivers. As the first baseline information on the river's biology and ecology, it may present a comparative basis for future assessments under conservation management strategies. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-03-29
Coastal movements and estuarine use of sub-adult and adult leervis, lichia amia: results from long-term acoustic tracking
- Authors: Mxo, Rebecca Vuyolwethu
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422314 , vital:71930
- Description: Information on fish movement is important not only for understanding a species’ ecological importance, but also for developing appropriate conservation and management policies that are critical for food security and biodiversity preservation. This information is particularly important for species that occupy different habitats at different life history stages, and display predictable movement patterns, such as an annual spawning migration. Leervis Lichia amia is an estuary-dependent fishery species of high ecological and recreational importance in South Africa. There has been a steady decline in catch-per-unit-effort in the marine recreational fishery for this species over the past 20 years, and the most recent stock assessment classified the adult stock as collapsed. This study investigates L. amia multi-year coastal migrations and estuarine habitat use of sub-adult and adult fish tagged with long-life acoustic transmitters Seventy-eight L. amia (two juveniles, fifty-four subadults, and twenty-one adults) were tagged throughout their South African distribution and monitored between 2011 and 2020 producing a decade long dataset. Results show that regardless of the tagging region, clear migration patterns were observed, demonstrating that both sub-adult and adult L. amia migrate annually to KZN in the austral winter and predictably return to the WC and EC waters in the summer. The likelihood of partial migration was also identified, with the coexistence of migratory and resident behaviors within a single L. amia population. In addition, Overwintering behaviour was also observed with L. amia adults that remained resident throughout the year, foregoing the annual migration, phenomenon known as skipped spawning, and homing behaviour, where L. amia, particularly those tagged in the EC and WC, were recorded returning to previously occupied tagging locations and surrounding areas. The importance of estuaries to sub-adult and adult fish was also assessed and identified the importance of estuaries not only to subadults but also to adults. Estuary visits were strongly influenced by the environment which the fish was tagged in, temporal and seasonal changes, and life-history stages. The predictability of their migrations (almost to the day), the varied migratory behaviour (overwintering), returning to sites of familiarity post-migration, and long-term dependency on estuaries even as sub-adults and adults, provide motivation for increased protection of this species, including extending the network of estuarine protected areas in the country, and a closed fishing season, particularly during the annual winter migration. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Mxo, Rebecca Vuyolwethu
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422314 , vital:71930
- Description: Information on fish movement is important not only for understanding a species’ ecological importance, but also for developing appropriate conservation and management policies that are critical for food security and biodiversity preservation. This information is particularly important for species that occupy different habitats at different life history stages, and display predictable movement patterns, such as an annual spawning migration. Leervis Lichia amia is an estuary-dependent fishery species of high ecological and recreational importance in South Africa. There has been a steady decline in catch-per-unit-effort in the marine recreational fishery for this species over the past 20 years, and the most recent stock assessment classified the adult stock as collapsed. This study investigates L. amia multi-year coastal migrations and estuarine habitat use of sub-adult and adult fish tagged with long-life acoustic transmitters Seventy-eight L. amia (two juveniles, fifty-four subadults, and twenty-one adults) were tagged throughout their South African distribution and monitored between 2011 and 2020 producing a decade long dataset. Results show that regardless of the tagging region, clear migration patterns were observed, demonstrating that both sub-adult and adult L. amia migrate annually to KZN in the austral winter and predictably return to the WC and EC waters in the summer. The likelihood of partial migration was also identified, with the coexistence of migratory and resident behaviors within a single L. amia population. In addition, Overwintering behaviour was also observed with L. amia adults that remained resident throughout the year, foregoing the annual migration, phenomenon known as skipped spawning, and homing behaviour, where L. amia, particularly those tagged in the EC and WC, were recorded returning to previously occupied tagging locations and surrounding areas. The importance of estuaries to sub-adult and adult fish was also assessed and identified the importance of estuaries not only to subadults but also to adults. Estuary visits were strongly influenced by the environment which the fish was tagged in, temporal and seasonal changes, and life-history stages. The predictability of their migrations (almost to the day), the varied migratory behaviour (overwintering), returning to sites of familiarity post-migration, and long-term dependency on estuaries even as sub-adults and adults, provide motivation for increased protection of this species, including extending the network of estuarine protected areas in the country, and a closed fishing season, particularly during the annual winter migration. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-03-29
Crop fields abandonment: assessing the dynamics of degradation in relation to leverage points for sustainable land management in the Macubeni catchment, South Africa
- Authors: Sibiya, Silindile
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422470 , vital:71945
- Description: Soil erosion is a major global environmental problem and a pervasive forms of land degradation that threatens land productivity and food and water security. Some of the biggest sources of sediment in catchments are previously cultivated lands. Regardless of this factor, the abandonment of cultivated fields is not well-researched. Sustainable land management (SLM) interventions can play a significant role in mitigating and halting land degradation. This study investigated the dynamics of degradation exhibited by crop fields and the potential impacts of SLM interventions, using a leverage points framework and a case study in the Macubeni catchment of South Africa. The research answers three questions: (1) What is the relationship between the usage status of crop fields and degradation in Macubeni? (2) What are the drivers of crop field abandonment and how do they interact in the system? (3) Can proposed sustainable land management interventions tackle the dynamics of land abandonment, and associated degradation, at the root cause level? An empirical-analytical approach using a four step multi-method process was followed, in which crop fields were mapped using ArcGIS tools, literature was reviewed alongside stakeholder engagements, qualitative systems mapping modelling was undertaken, and a Multi-Criteria Analysis (MCA) with leverage points hierarchy was used to integrate all the steps together. The results revealed that the various drivers of crop field abandonment include natural environmental factors, socio-economic and social factors. 47.41% of the total crop fields in Macubeni were classified as highly degraded, and abandoned fields covered 37.47%. The statistical Chi-Square Test also confirmed that there is a significant relationship between the usage status and degradation level in crop fields. The SLM interventions assessed in the study have the potential to tackle the dynamics of land abandonment at a root cause level, however, there is a need to first shift the community’s mental models to address the existing sources of change resistance that are hindering successful implementation. Furthermore, the innovative multi-method approach applied in this study can further provide a holistic, dynamic, and integrated decision-support to land conservation and rehabilitation projects in similar settings across South Africa and other developing countries as opposed to the more traditional one-dimensional approaches. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Sibiya, Silindile
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422470 , vital:71945
- Description: Soil erosion is a major global environmental problem and a pervasive forms of land degradation that threatens land productivity and food and water security. Some of the biggest sources of sediment in catchments are previously cultivated lands. Regardless of this factor, the abandonment of cultivated fields is not well-researched. Sustainable land management (SLM) interventions can play a significant role in mitigating and halting land degradation. This study investigated the dynamics of degradation exhibited by crop fields and the potential impacts of SLM interventions, using a leverage points framework and a case study in the Macubeni catchment of South Africa. The research answers three questions: (1) What is the relationship between the usage status of crop fields and degradation in Macubeni? (2) What are the drivers of crop field abandonment and how do they interact in the system? (3) Can proposed sustainable land management interventions tackle the dynamics of land abandonment, and associated degradation, at the root cause level? An empirical-analytical approach using a four step multi-method process was followed, in which crop fields were mapped using ArcGIS tools, literature was reviewed alongside stakeholder engagements, qualitative systems mapping modelling was undertaken, and a Multi-Criteria Analysis (MCA) with leverage points hierarchy was used to integrate all the steps together. The results revealed that the various drivers of crop field abandonment include natural environmental factors, socio-economic and social factors. 47.41% of the total crop fields in Macubeni were classified as highly degraded, and abandoned fields covered 37.47%. The statistical Chi-Square Test also confirmed that there is a significant relationship between the usage status and degradation level in crop fields. The SLM interventions assessed in the study have the potential to tackle the dynamics of land abandonment at a root cause level, however, there is a need to first shift the community’s mental models to address the existing sources of change resistance that are hindering successful implementation. Furthermore, the innovative multi-method approach applied in this study can further provide a holistic, dynamic, and integrated decision-support to land conservation and rehabilitation projects in similar settings across South Africa and other developing countries as opposed to the more traditional one-dimensional approaches. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Date Issued: 2023-03-29
Distribution and conservation status assessment of the freshwater fishes in the Krom River system in the Eastern Cape Province, South Africa
- Authors: Mthombeni, Annah
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422303 , vital:71929
- Description: The Cape Fold Ecoregion (CFE) contains the highest number of endemic freshwater fishes in Africa, south of the Zambezi River system. The CFE’s unique fish fauna has, however, suffered severe decline in historical distribution ranges and population sizes due to multiple impacts, with the two main threats being introduced invasive piscivores and habitat degradation. Growing evidence shows that biodiversity is being lost at unprecedented levels due to increased human pressure and demand for limited resources. Future projections also indicate high extinction risk, particularly for freshwater ecosystems, as a result of global climate change. Yet for many regions, including the CFE, there is still limited biodiversity knowledge to guide decision making processes. The Krom River system in the eastern Cape Fold Ecoregion (CFE) contains three native freshwater fish species. These are Pseudobarbus senticeps, which was recently revalidated, Sandelia capensis and a galaxiid lineage currently informally referred to as Galaxias zebratus sp. ‘Joubertina’. Two of these taxa are listed under threatened categories of the International Union for Conservation of Nature (IUCN). These are P. senticeps, which is listed as Critically Endangered and Galaxias zebratus sp. ‘Joubertina’, which is listed as Endangered. Although S. capensis is currently listed as Data Deficient, the most recent information indicates that the species comprises three allopatric lineages, with the Krom River population belonging to a lineage that is distributed across a number of river systems on the south coast. Two non-native fishes, Micropterus salmoides and Lepomis macrochirus, have also been introduced into this river system. Updated information on distribution patterns and habitat utilisation is required to guide authorities to develop effective management plans and conservation of the threatened fishes of the Krom River system. The aim of this study was to determine the current distribution of the fishes of the Krom River system and to provide recommendations for in situ conservation measures to protect remnant populations and promote recovery and range expansion of the native fishes. The primary objective of the study was to use historical and present data to map the distributions patterns. Data on the distribution of the fishes of the Krom River system were obtained from various sources, including the NRF-SAIAB database, studies published in peer reviewed literature and unpublished reports. Systematic sampling was conducted in the Krom River system and several of its tributaries to provide a snapshot of the current distribution of both native and non-native fishes in this system at the time of this study. The presence of instream physical barriers was recorded, and habitat and water quality were visually assessed. Only four species of freshwater fishes were recorded during the surveys. These were two native species, the Krom River redfin P. senticeps and the Cape kurper Sandelia capensis, and two introduced species, the black bass M. salmoides and bluegill sunfish L. macrochirus. Pseudobarbus senticeps was the most common and widely distributed species in the system, and was recorded at 20 localities (four mainstem and 16 tributary localities). Sandelia capensis was less common and was recorded at only eight localities (four mainstem and four tributary localities). These two native species co-occurred at all the eight localities where S. capensis was recorded, but P. senticeps was always more abundant than Sandelia. Micropterus salmoides was recorded at six localities (four mainstem and 2 tributary localities) while L. macrochirus was recorded at five localities (four mainstem and one off-stream dam site). Native fishes were not recorded at sites where non-native fishes were present except at two localities in the Wit Els River where juvenile M. salmoides were found amongst the native fish samples. However, unlike the other localities where all size classes (i.e., young of the year, juveniles, subadults and adults) were present, only adult redfins were found in the Wit Els River where juveniles of largemouth bass occurred. A comparison of the past and present distribution patterns of the native fishes indicates a considerable decline in distribution range, and remnant populations are now fragmented compared to past observations. The major threats and impacts on the Krom River system are the presence of non-native piscivores, construction of instream physical barriers, and agricultural activities. The information from this study could form a basis for establishing long-term conservation measures that should focus on preventing the spread of non-native fishes, and rehabilitating critical habitats for the future persistence of remnant populations of native fishes. The study also evaluated the implications of incomplete taxonomy on conservation status assessments and prioritisation, by evaluating case studies of species complexes of freshwater fishes whose taxonomy has been recently resolved, as well as two complexes with lineages that await formal recognition as distinct species. The aim was to demonstrate how incomplete knowledge of taxonomy affects the assessment of extinction risk and can potentially misdirect conservation prioritisation. Specifically, the study examined how change in taxonomy or recognition of undescribed genetic lineages in faunal listings affects range size and IUCN Red List risk category. The study taxa were Pseudobarbus afer sensu lato (sl), Enteromius anoplus sl, Amphilius natalensis sl, Sandelia capensis and S. bainsii, and the study assessed the species complexes as Least Concern or Near Threatened. The majority of these taxonomically revised species and genetic lineages were determined to be Critically Endangered (CR), Endangered (EN) and Vulnerable (VU), as the extent of occurrence was estimated to be < 100 km2; < 5000 km2 and < 20 000 km2 respectively. The species and lineages have been observed in fewer than ten locations, and the populations have been observed to be in decline. The results of this study indicate that the current taxonomic status of the native species in the Krom River system obscures the diversity of these fishes and affects conclusions for conservation assessments. Findings from this preliminary assessment highlight the need for advancing taxonomic knowledge through accurate delimitation of species boundaries, particularly within , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Mthombeni, Annah
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422303 , vital:71929
- Description: The Cape Fold Ecoregion (CFE) contains the highest number of endemic freshwater fishes in Africa, south of the Zambezi River system. The CFE’s unique fish fauna has, however, suffered severe decline in historical distribution ranges and population sizes due to multiple impacts, with the two main threats being introduced invasive piscivores and habitat degradation. Growing evidence shows that biodiversity is being lost at unprecedented levels due to increased human pressure and demand for limited resources. Future projections also indicate high extinction risk, particularly for freshwater ecosystems, as a result of global climate change. Yet for many regions, including the CFE, there is still limited biodiversity knowledge to guide decision making processes. The Krom River system in the eastern Cape Fold Ecoregion (CFE) contains three native freshwater fish species. These are Pseudobarbus senticeps, which was recently revalidated, Sandelia capensis and a galaxiid lineage currently informally referred to as Galaxias zebratus sp. ‘Joubertina’. Two of these taxa are listed under threatened categories of the International Union for Conservation of Nature (IUCN). These are P. senticeps, which is listed as Critically Endangered and Galaxias zebratus sp. ‘Joubertina’, which is listed as Endangered. Although S. capensis is currently listed as Data Deficient, the most recent information indicates that the species comprises three allopatric lineages, with the Krom River population belonging to a lineage that is distributed across a number of river systems on the south coast. Two non-native fishes, Micropterus salmoides and Lepomis macrochirus, have also been introduced into this river system. Updated information on distribution patterns and habitat utilisation is required to guide authorities to develop effective management plans and conservation of the threatened fishes of the Krom River system. The aim of this study was to determine the current distribution of the fishes of the Krom River system and to provide recommendations for in situ conservation measures to protect remnant populations and promote recovery and range expansion of the native fishes. The primary objective of the study was to use historical and present data to map the distributions patterns. Data on the distribution of the fishes of the Krom River system were obtained from various sources, including the NRF-SAIAB database, studies published in peer reviewed literature and unpublished reports. Systematic sampling was conducted in the Krom River system and several of its tributaries to provide a snapshot of the current distribution of both native and non-native fishes in this system at the time of this study. The presence of instream physical barriers was recorded, and habitat and water quality were visually assessed. Only four species of freshwater fishes were recorded during the surveys. These were two native species, the Krom River redfin P. senticeps and the Cape kurper Sandelia capensis, and two introduced species, the black bass M. salmoides and bluegill sunfish L. macrochirus. Pseudobarbus senticeps was the most common and widely distributed species in the system, and was recorded at 20 localities (four mainstem and 16 tributary localities). Sandelia capensis was less common and was recorded at only eight localities (four mainstem and four tributary localities). These two native species co-occurred at all the eight localities where S. capensis was recorded, but P. senticeps was always more abundant than Sandelia. Micropterus salmoides was recorded at six localities (four mainstem and 2 tributary localities) while L. macrochirus was recorded at five localities (four mainstem and one off-stream dam site). Native fishes were not recorded at sites where non-native fishes were present except at two localities in the Wit Els River where juvenile M. salmoides were found amongst the native fish samples. However, unlike the other localities where all size classes (i.e., young of the year, juveniles, subadults and adults) were present, only adult redfins were found in the Wit Els River where juveniles of largemouth bass occurred. A comparison of the past and present distribution patterns of the native fishes indicates a considerable decline in distribution range, and remnant populations are now fragmented compared to past observations. The major threats and impacts on the Krom River system are the presence of non-native piscivores, construction of instream physical barriers, and agricultural activities. The information from this study could form a basis for establishing long-term conservation measures that should focus on preventing the spread of non-native fishes, and rehabilitating critical habitats for the future persistence of remnant populations of native fishes. The study also evaluated the implications of incomplete taxonomy on conservation status assessments and prioritisation, by evaluating case studies of species complexes of freshwater fishes whose taxonomy has been recently resolved, as well as two complexes with lineages that await formal recognition as distinct species. The aim was to demonstrate how incomplete knowledge of taxonomy affects the assessment of extinction risk and can potentially misdirect conservation prioritisation. Specifically, the study examined how change in taxonomy or recognition of undescribed genetic lineages in faunal listings affects range size and IUCN Red List risk category. The study taxa were Pseudobarbus afer sensu lato (sl), Enteromius anoplus sl, Amphilius natalensis sl, Sandelia capensis and S. bainsii, and the study assessed the species complexes as Least Concern or Near Threatened. The majority of these taxonomically revised species and genetic lineages were determined to be Critically Endangered (CR), Endangered (EN) and Vulnerable (VU), as the extent of occurrence was estimated to be < 100 km2; < 5000 km2 and < 20 000 km2 respectively. The species and lineages have been observed in fewer than ten locations, and the populations have been observed to be in decline. The results of this study indicate that the current taxonomic status of the native species in the Krom River system obscures the diversity of these fishes and affects conclusions for conservation assessments. Findings from this preliminary assessment highlight the need for advancing taxonomic knowledge through accurate delimitation of species boundaries, particularly within , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-03-29
Enhancing the use of large-scale assessment data in South Africa: Multidimensional Item Response Theory
- Authors: Lahoud, Tamlyn Ann
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422389 , vital:71938
- Description: This research aims to enhance the use of large-scale assessment data in South Africa by evaluating assessment validity by means of multidimensional item response theory and its associated statistical techniques, which have been severely underutilised. Data from the 2014 administration of the grade 6 Mathematics annual national assessment was used in this study and all analyses were conducted using the mirt package in R. A two parameter logistic item response theory model was developed which indicated a clear alignment between the model parameters and difficulty specifications of the test. The test was found to favour learners within the central band on the ability scale. An exploratory five dimensional item response theory model was then developed to investigate the alignment with the test specifications as evidence for construct validity. Significant discrepancies between the factor structure and the specifications of the test were identified. Notably, the results suggest that some items measured an ability that was not purely mathematical, such as reading ability, which would distort the test’s representation of Mathematics ability, disadvantage learners with lower English literacy, and reduce the construct validity of the test. Further validity evidence was obtained by differential item functioning analyses which revealed that fourteen items function differently for learners from different provinces. Although possible reasons for the presence of differential item functioning among provinces were not discussed, its presence provided sufficient evidence against the validity of the test. In conclusion, multidimensional item response theory provided an effective and rigorous approach to establishing the validity of a large-scale assessment. To avoid the pitfalls of the annual national assessments, it is recommended that this multidimensional item and differential item functioning techniques are utilised for the development and evaluation of future national assessment instruments in South Africa. , Thesis (MSc) -- Faculty of Science, Statistics, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Lahoud, Tamlyn Ann
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422389 , vital:71938
- Description: This research aims to enhance the use of large-scale assessment data in South Africa by evaluating assessment validity by means of multidimensional item response theory and its associated statistical techniques, which have been severely underutilised. Data from the 2014 administration of the grade 6 Mathematics annual national assessment was used in this study and all analyses were conducted using the mirt package in R. A two parameter logistic item response theory model was developed which indicated a clear alignment between the model parameters and difficulty specifications of the test. The test was found to favour learners within the central band on the ability scale. An exploratory five dimensional item response theory model was then developed to investigate the alignment with the test specifications as evidence for construct validity. Significant discrepancies between the factor structure and the specifications of the test were identified. Notably, the results suggest that some items measured an ability that was not purely mathematical, such as reading ability, which would distort the test’s representation of Mathematics ability, disadvantage learners with lower English literacy, and reduce the construct validity of the test. Further validity evidence was obtained by differential item functioning analyses which revealed that fourteen items function differently for learners from different provinces. Although possible reasons for the presence of differential item functioning among provinces were not discussed, its presence provided sufficient evidence against the validity of the test. In conclusion, multidimensional item response theory provided an effective and rigorous approach to establishing the validity of a large-scale assessment. To avoid the pitfalls of the annual national assessments, it is recommended that this multidimensional item and differential item functioning techniques are utilised for the development and evaluation of future national assessment instruments in South Africa. , Thesis (MSc) -- Faculty of Science, Statistics, 2023
- Full Text:
- Date Issued: 2023-03-29
Exploring aspects of Community of Inquiry (CoI) in Afrophilia learning processes for transformative education using an Afrophilic ‘Philosophy for Children’ approach: a case of Sebakwe resettlement primary schools in the Midlands Province of Zimbabwe
- Authors: Bhurekeni, John
- Date: 2023-03-29
- Subjects: Culturally relevant pedagogy Zimbabwe , Curriculum change Zimbabwe , Philosophy Study and teaching (Elementary) Zimbabwe , Critical thinking , Decolonization Zimbabwe , Technology Political aspects , Representation (Philosophy)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366178 , vital:65840 , DOI https://doi.org/10.21504/10962/366178
- Description: This study focused on investigating and developing an Afrophilic orientation to a sociocultural approach to philosophy for children. The main aim was to foster a critical and generative approach to considering the heritage-based curriculum foundations of Zimbabwean primary schools, focusing on Sebakwe resettlement primary schools (the case study area). Afrophilia foundations in the study are regarded as “the discourses that are the medium of philosophical reflexion” (Rettova, 2004, p. 4) in each African society. As articulated in the study, such discourses include African proverbs, poems, stories, music, and folktales which are useful in the initiation of philosophical engagements with children in a community of inquiry approach. A community of inquiry is a framework that reflects a collaborative-dialogical approach to teaching and learning. Curriculum reviews in postcolonial Zimbabwe have revealed an unconscious misalignment of the Zimbabwean education system's philosophical underpinnings because it has continued to align itself with imperial British colonial philosophy, which contradicts the country's developmental needs (Presidential Commission of Inquiry into Education and Training [CIET], 1999, Zimbabwe Ministry of Primary and Secondary Education [MoPSE], 2014). The philosophical misalignment is an extension of the colonial history of Zimbabwe showing that vestiges of colonial rule still shape the education sector. This leaves the education system focusing mainly on abstracted concepts with continued marginalisation of local cultures, discourses, and knowledge. Consequently, it leaves Zimbabwe together with other postcolonial education systems with the task of dealing with the phenomenon of colonial continuity. One implication of these colonial continuities, is learner disinterest in learning, which affects the educational process negatively, affecting the learning of critical reflexive thinking, an issue which I have observed in the Sebakwe resettlement schools involved in this study where I have been teaching for 15 years. To address, this, the study sought to answer the following questions: What historical and contemporary barriers are affecting the promotion of a culture of learning in Zimbabwean resettlement primary schools, particularly as they relate to learners' underdevelopment of critical reflexive thinking skills? In addition, How can the Philosophy for Children Afrophilia curriculum intervention promote a culture of learning in Sebakwe resettlement primary schools that is oriented toward the development of critical reflexive thinking skills in children? In approaching the research questions, I applied postcolonial and decolonisation theory, sociocultural learning theory and curriculum theory aimed at transformative change, that is oriented towards achieving a more contextually oriented approach to teaching and learning, and a paradigm of ‘learning as connection’ (Lotz-Sisitka & Lupele, 2017; Shumba, 2017). This has been identified as a ‘missing’ discourse in mainstream educational quality discourses in southern Africa (Lotz-Sisitka & Lupele, 2017). Furthermore, to create space for curriculum development using multi-actor groups in a community of inquiry, I used decolonial research methodologies in the data generation process. The study is constituted as an interventionist case study, and I applied a four-stage process comprising document analysis, workshops, participant observations involving children between 8-11 years, and reflective interviews with parents, educators and children as instruments for data gathering. I also used process-based analytical tools developed in Philosophy of Children research to analyse the processes of critical reflexive thinking development that emerged from the Philosophy for Children pedagogy involving ten lessons which I facilitated, and videorecorded. Moreover, I used postcolonial and decolonial discourse analysis to provide the broader analytical insights that informed the interpretations of the lesson analysis data from the perspective of the research problem that I address across the research project. This PhD is produced as a PhD by publication, which involves publishing of papers, and orientation to, and interpretation of the papers. The main findings of this study are reported in articles that I prepared for publication, three of which have already been published (see Appendices A1, A4 and A5), and four which have been submitted for publication (A2, A3, A6, A7) with some already at an advanced stage of finalisation via review. The conceptual paper (A1) that served as the foundation for the publication journey revealed that, in addition to the weight of cultural technologies of domination, the curriculum is shaped by the paradox of a superficial interpretation of unhu/ubuntu educational philosophy. As a result, the curriculum becomes disconnected from the learners' real-world experiences. The second paper (A2), which focuses on why Zimbabwe needs the Philosophy for Children approach with a sociocultural medley, unveils Zimbabwe's complex decolonial curriculum reforms and their many contradictions and paradoxes. However, it also emerged that the approach used in this study empowers teachers, is relevant to the emerging constellation of practices in the Sebakwe resettlement, and influences power sharing beyond teacher-child relationships. The third paper (A3), based on children’s philosophy for children practice, defends the study’s decision to bring children’s heritage and cultural lens to bear on curriculum and pedagogical praxis. In essence, the article explores a synergy between philosophy for children and the Zimbabwean heritage-based educational curriculum, serving to enrich both. The fourth paper (A4) makes the case that philosophy for children could be a viable pedagogy for transformative education, and it provides evidence-based implementation of a context-based philosophy for children. According to this paper, the approach is effective in strengthening strong community relationships, instilling pride in local heritage, and advancing curriculum transformation. The fifth paper (A5) focusses on the approach's implications for teachers' roles, practices, and competencies. Six dimensions of teacher roles, practices, and competences surfaced, including the role of the teacher as a decoloniser and pedagogical innovator, among others. The sixth paper (A6), influenced by the previous papers' findings, focused on decolonisation and improving learning opportunities for children in the Sebakwe area using the philosophy for children approach. This paper's data depicts a ‘third space’ in which learners consolidate their cultural capital and curriculum content into their own meaning construction. The implication is that schools become neutral sites that improve learners' interdependence and inclusivity while also taking contextual realities into account. The findings of the seventh and final paper (A7) presented in this write-up advance the idea that a Philosophy for Children approach with a sociocultural medley influences an ethics of care by demonstrating how Afrophilia experiences influence a new path to wildlife conservation and sustainability. The study highlights that integrating Philosophy for Children and Afrophilia foundations of knowledge into the school curriculum promotes critical reflexive thinking skills, helps to address real-life problems and adds relevance to the curriculum. The study further shows that the integration of philosophy for children in the advancement of curriculum transformation in Zimbabwe is a successful formative interventionist approach in the resettlement schools that are characterised by a critical shortage of teaching and learning resources. In essence, the research opens an understanding that curriculum transformation and decolonisation are context-based and multi-actor processes, as showcased in the experiences of parents, teachers, education inspectors, and children in this study. Furthermore, this study posits that situating curriculum decolonization and transformation within unhu/ubuntu dialectical rationality and advancing diversity in reasoning necessitates deeper engagement with heritage-based curriculum and provides teachers with appropriate agency to modify and adapt their pedagogies in alignment with the learners' life world. According to the study, this emerged as a rational possible solution to the problem of curriculum decontextualisation. Curriculum decontextualisation as highlighted in the study via the problem of colonial continuity mentioned above, appears to be further influenced by the emphasis on examination assessment scores which seem to widen the gap between the adult and child worlds, as well as the gap between contextual realities and [curriculum] examination content. Overall, the study offers an approach that can deepen an unhu/ubuntu foundation for the heritage-based curriculum reform in Zimbabwe, and strengthen the learning of children in the resettlement schools, where the case was explored. Implications for further research are elaborated, as are possible implications for policy and practice. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Bhurekeni, John
- Date: 2023-03-29
- Subjects: Culturally relevant pedagogy Zimbabwe , Curriculum change Zimbabwe , Philosophy Study and teaching (Elementary) Zimbabwe , Critical thinking , Decolonization Zimbabwe , Technology Political aspects , Representation (Philosophy)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366178 , vital:65840 , DOI https://doi.org/10.21504/10962/366178
- Description: This study focused on investigating and developing an Afrophilic orientation to a sociocultural approach to philosophy for children. The main aim was to foster a critical and generative approach to considering the heritage-based curriculum foundations of Zimbabwean primary schools, focusing on Sebakwe resettlement primary schools (the case study area). Afrophilia foundations in the study are regarded as “the discourses that are the medium of philosophical reflexion” (Rettova, 2004, p. 4) in each African society. As articulated in the study, such discourses include African proverbs, poems, stories, music, and folktales which are useful in the initiation of philosophical engagements with children in a community of inquiry approach. A community of inquiry is a framework that reflects a collaborative-dialogical approach to teaching and learning. Curriculum reviews in postcolonial Zimbabwe have revealed an unconscious misalignment of the Zimbabwean education system's philosophical underpinnings because it has continued to align itself with imperial British colonial philosophy, which contradicts the country's developmental needs (Presidential Commission of Inquiry into Education and Training [CIET], 1999, Zimbabwe Ministry of Primary and Secondary Education [MoPSE], 2014). The philosophical misalignment is an extension of the colonial history of Zimbabwe showing that vestiges of colonial rule still shape the education sector. This leaves the education system focusing mainly on abstracted concepts with continued marginalisation of local cultures, discourses, and knowledge. Consequently, it leaves Zimbabwe together with other postcolonial education systems with the task of dealing with the phenomenon of colonial continuity. One implication of these colonial continuities, is learner disinterest in learning, which affects the educational process negatively, affecting the learning of critical reflexive thinking, an issue which I have observed in the Sebakwe resettlement schools involved in this study where I have been teaching for 15 years. To address, this, the study sought to answer the following questions: What historical and contemporary barriers are affecting the promotion of a culture of learning in Zimbabwean resettlement primary schools, particularly as they relate to learners' underdevelopment of critical reflexive thinking skills? In addition, How can the Philosophy for Children Afrophilia curriculum intervention promote a culture of learning in Sebakwe resettlement primary schools that is oriented toward the development of critical reflexive thinking skills in children? In approaching the research questions, I applied postcolonial and decolonisation theory, sociocultural learning theory and curriculum theory aimed at transformative change, that is oriented towards achieving a more contextually oriented approach to teaching and learning, and a paradigm of ‘learning as connection’ (Lotz-Sisitka & Lupele, 2017; Shumba, 2017). This has been identified as a ‘missing’ discourse in mainstream educational quality discourses in southern Africa (Lotz-Sisitka & Lupele, 2017). Furthermore, to create space for curriculum development using multi-actor groups in a community of inquiry, I used decolonial research methodologies in the data generation process. The study is constituted as an interventionist case study, and I applied a four-stage process comprising document analysis, workshops, participant observations involving children between 8-11 years, and reflective interviews with parents, educators and children as instruments for data gathering. I also used process-based analytical tools developed in Philosophy of Children research to analyse the processes of critical reflexive thinking development that emerged from the Philosophy for Children pedagogy involving ten lessons which I facilitated, and videorecorded. Moreover, I used postcolonial and decolonial discourse analysis to provide the broader analytical insights that informed the interpretations of the lesson analysis data from the perspective of the research problem that I address across the research project. This PhD is produced as a PhD by publication, which involves publishing of papers, and orientation to, and interpretation of the papers. The main findings of this study are reported in articles that I prepared for publication, three of which have already been published (see Appendices A1, A4 and A5), and four which have been submitted for publication (A2, A3, A6, A7) with some already at an advanced stage of finalisation via review. The conceptual paper (A1) that served as the foundation for the publication journey revealed that, in addition to the weight of cultural technologies of domination, the curriculum is shaped by the paradox of a superficial interpretation of unhu/ubuntu educational philosophy. As a result, the curriculum becomes disconnected from the learners' real-world experiences. The second paper (A2), which focuses on why Zimbabwe needs the Philosophy for Children approach with a sociocultural medley, unveils Zimbabwe's complex decolonial curriculum reforms and their many contradictions and paradoxes. However, it also emerged that the approach used in this study empowers teachers, is relevant to the emerging constellation of practices in the Sebakwe resettlement, and influences power sharing beyond teacher-child relationships. The third paper (A3), based on children’s philosophy for children practice, defends the study’s decision to bring children’s heritage and cultural lens to bear on curriculum and pedagogical praxis. In essence, the article explores a synergy between philosophy for children and the Zimbabwean heritage-based educational curriculum, serving to enrich both. The fourth paper (A4) makes the case that philosophy for children could be a viable pedagogy for transformative education, and it provides evidence-based implementation of a context-based philosophy for children. According to this paper, the approach is effective in strengthening strong community relationships, instilling pride in local heritage, and advancing curriculum transformation. The fifth paper (A5) focusses on the approach's implications for teachers' roles, practices, and competencies. Six dimensions of teacher roles, practices, and competences surfaced, including the role of the teacher as a decoloniser and pedagogical innovator, among others. The sixth paper (A6), influenced by the previous papers' findings, focused on decolonisation and improving learning opportunities for children in the Sebakwe area using the philosophy for children approach. This paper's data depicts a ‘third space’ in which learners consolidate their cultural capital and curriculum content into their own meaning construction. The implication is that schools become neutral sites that improve learners' interdependence and inclusivity while also taking contextual realities into account. The findings of the seventh and final paper (A7) presented in this write-up advance the idea that a Philosophy for Children approach with a sociocultural medley influences an ethics of care by demonstrating how Afrophilia experiences influence a new path to wildlife conservation and sustainability. The study highlights that integrating Philosophy for Children and Afrophilia foundations of knowledge into the school curriculum promotes critical reflexive thinking skills, helps to address real-life problems and adds relevance to the curriculum. The study further shows that the integration of philosophy for children in the advancement of curriculum transformation in Zimbabwe is a successful formative interventionist approach in the resettlement schools that are characterised by a critical shortage of teaching and learning resources. In essence, the research opens an understanding that curriculum transformation and decolonisation are context-based and multi-actor processes, as showcased in the experiences of parents, teachers, education inspectors, and children in this study. Furthermore, this study posits that situating curriculum decolonization and transformation within unhu/ubuntu dialectical rationality and advancing diversity in reasoning necessitates deeper engagement with heritage-based curriculum and provides teachers with appropriate agency to modify and adapt their pedagogies in alignment with the learners' life world. According to the study, this emerged as a rational possible solution to the problem of curriculum decontextualisation. Curriculum decontextualisation as highlighted in the study via the problem of colonial continuity mentioned above, appears to be further influenced by the emphasis on examination assessment scores which seem to widen the gap between the adult and child worlds, as well as the gap between contextual realities and [curriculum] examination content. Overall, the study offers an approach that can deepen an unhu/ubuntu foundation for the heritage-based curriculum reform in Zimbabwe, and strengthen the learning of children in the resettlement schools, where the case was explored. Implications for further research are elaborated, as are possible implications for policy and practice. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
Expression, partial characterisation and utilization of a GH11 xylanase (Xyn2A) from Trichoderma viride as an additive in monogastric animal feeds
- Mzimkulu-Ncoyi, Nosabatha Happyness
- 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
- Full Text:
- Date Issued: 2023-03-29
- 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
- Full Text:
- Date Issued: 2023-03-29