Drug development and animal welfare: bioethical analysis of emergency situations and the research settings
- Authors: Msimang, Asante
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461852 , vital:76245
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Msimang, Asante
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461852 , vital:76245
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
Screening and characterisation of novel compounds and their derivatives from South African medicinal plants against triple negative breast cancer cells
- Authors: Nyemba, Getrude Rutendo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463952 , vital:76460
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Nyemba, Getrude Rutendo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463952 , vital:76460
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Using in silico approaches to ascertain selective novel orthosteric and allosteric inhibitors of plasmodium falciparum Prolyl-tRNA synthetase for the development of antimalarial drugs
- Authors: Ramahala, Rabelani
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463963 , vital:76461
- Description: Access restricted. Exxpected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ramahala, Rabelani
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463963 , vital:76461
- Description: Access restricted. Exxpected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Do the Cytochrome P450 1A2 allele variations have an effect on the structure and function of the protein?
- Authors: Mondile, Queenie
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463907 , vital:76456
- Description: Access restricted. Expected release in 2025. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mondile, Queenie
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463907 , vital:76456
- Description: Access restricted. Expected release in 2025. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Redefinition of a refugee during conditions of disaster uncertainty of COVID19 in South Africa and beyond
- Authors: Maguire, Kelly Ann
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461841 , vital:76244
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Maguire, Kelly Ann
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461841 , vital:76244
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
Elucidating the effect of potential mitochondrial toxicants on glucose handling and insulin signalling in skeletal muscle and liver cell lines in vitro
- Authors: Kuretu, Auxiliare
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461830 , vital:76243
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Kuretu, Auxiliare
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461830 , vital:76243
- Description: Access restricited. Expected release date 2026. , Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 2024
- Full Text:
- Date Issued: 2024-10-11
Development of a novel agar-based microtitre plate system for construction of consistent biofilm models and subsequent use in antimicrobial screening
- Authors: Davies, Michaela Roxanne
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464369 , vital:76505
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Davies, Michaela Roxanne
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464369 , vital:76505
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
Evaluation of screening methods for aptamer-target affinity: towards biosensors for the detection of histamine and human chorionic gonadotropin
- Authors: Yu, Jialin
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464395 , vital:76507
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Yu, Jialin
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464395 , vital:76507
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
Development of efficient protocols to generate breast cancer spheroids for application in drug discovery
- Ntsoyi, Nomaphelo Ntombikayise
- Authors: Ntsoyi, Nomaphelo Ntombikayise
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464380 , vital:76506
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ntsoyi, Nomaphelo Ntombikayise
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464380 , vital:76506
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
Design and fabrication of millifluidic devices for maintenance of tissue cultures under perfusion
- Buthelezi, Khanyisile Thando Fatima
- Authors: Buthelezi, Khanyisile Thando Fatima
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464358 , vital:76504
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Buthelezi, Khanyisile Thando Fatima
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464358 , vital:76504
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
The expression and evaluation of CrpeNPV gp37 as a formulation additive for enhanced infectivity with CrleGV-SA and improved Thaumatotibia leucotreta control
- Authors: Muleya, Naho
- Date: 2024-10-11
- Subjects: Cryptophlebia leucotreta Biological control , False Codling Moth , Cryptophlebia leucotreta granulovirus , Cryptophlebia peltastica nucleopolyhedrovirus , Citrus Diseases and pests South Africa , Baculoviruses
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463919 , vital:76457
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a significant pest native to Africa, causing damage to citrus and posing a threat to the export of fresh citrus in South Africa. Classified as a phytosanitary risk by several South African export markets, this pest necessitates effective control measures. Baculoviruses emerge as promising biological control agents against T. leucotreta due to their inherent safety and eco-friendly characteristics. Among these, Cryptophlebia leucotreta Granulovirus (CrleGV-SA) and Cryptophlebia peltastica Nucleopolyhedrovirus (CrpeNPV) stand out, both causing larval mortality upon infecting T. leucotreta. CrleGV-SA has been formulated into the products Cryptogran™, CryptoMax™ and Cryptex®, while CrpeNPV has been formulated into the product Multimax™. Both viruses are used in integrated pest management programmes to reduce fruit damage in agricultural fields, with CrleGV-SA having been employed against T. leucotreta for nearly 20 years in South Africa. However, these control options are limited by factors such as virulence and the slow speed of kill. This limitation can be addressed by exploiting potential synergistic relationships between baculoviruses infecting the same host. Previous studies have demonstrated that the truncated CpGV gp37 can enhance the infectivity of NPVs on other lepidopteran pests, such as Spodoptera exigua (Hübner). Although the mechanism behind this phenomenon remains unclear, it presents an opportunity to enhance the effectiveness of baculovirus-based management strategies. Notably, the genome of CrpeNPV encodes gp37, while CrleGV-SA lacks this gene. The potential interaction between CrleGV-SA and CrpeNPV gp37 remains unexplored. Therefore, investigating whether they exhibit synergistic or antagonistic effects is essential for optimising baculovirus-based management of T. leucotreta. This study aims to express CrpeNPV gp37 in a bacterial system and then evaluate its effect on larval mortality when combined with CrleGV-SA in laboratory bioassays. The initial step involved extracting genomic DNA (gDNA) from occlusion bodies (OBs) of CrpeNPV. A modified Quick DNA Miniprep plus kit was utilised, which entailed pre-treatment with Na2CO3 followed by neutralisation with Tris-HCI before gDNA extraction using the kit. Subsequently, the concentration of the gDNA was estimated using a Nanodrop spectrophotometer. Oligonucleotides targeting the CrpeNPV gp37 gene were designed for PCR amplification, with the gDNA serving as a template. The gp37 amplicon was identified through agarose gel electrophoresis and then gel purified in preparation for cloning. Secondly, the purified PCR product was cloned into the intermediate vector pJET1.2/blunt and then subcloned into the bacterial expression vector pCA528 through DNA ligation. The construction of recombinant plasmids (pJET-gp37 and pCA-gp37) was conducted and verified using Colony PCR, plasmid extraction, restriction enzyme analysis, and Sanger sequencing. Thirdly, the recombinant protein (6×His-SUMO-gp37) was expressed and purified using Nickel affinity chromatography and analysed through SDS-PAGE and Western blot techniques. The expression of 6×His-SUMO-gp37 was carried out at both 25 °C and 18 °C. A time course induction study was conducted, inducing transformed cells for 0-, 3-, 5-, and 24-hours post induction (hpi). SDS-PAGE and Western blotting of samples collected at various time points revealed that 6×His-SUMO-gp37, approximately 42 kDa in size, was visible from 3 hpi, with maximal expression at 24 hpi. Solubility analysis of 6×His-SUMO-gp37 was performed at both temperatures, showing solubility at 18 °C but predominantly present in the insoluble fraction. The soluble protein was purified under native conditions, while the insoluble protein was purified under denaturing conditions. Despite being unable to elute 6×His-SUMO-gp37 under native conditions, successful elution was achieved under denaturing conditions, confirmed via Western blot analysis. No further experiments were conducted on the eluted 6×His-SUMO-gp37 under denaturing conditions. Lastly, a preliminary surface dose bioassay was conducted to evaluate the efficacy of pelleted bacteria expressing 6×His-SUMO-gp37 in combination with CrleGV-SA against T. leucotreta neonates. Two lethal concentration doses of CrleGV-SA were prepared: a low concentration (2.96×104 OBs/mL) capable of killing 40 % of the T. leucotreta population, and a high concentration (2.96×105 OBs/mL) capable of killing 90 % of the population. The target protein, 6×His-SUMO-gp37, and the control, pCA528, were obtained by lysing the cells, centrifuging the samples, and collecting the insoluble fractions in pellet form. These fractions were then resuspended in PBS and used as treatments in combination with the prepared CrleGV-SA concentration doses. The concentration of the pellets was estimated using a Nanodrop spectrophotometer by measuring the absorbance at 280 nm. The bioassay results revealed that the combination of 100 μg/mL of pelleted bacteria expressing 6×His-SUMO-gp37 with CrleGV-SA had no effect on T. leucotreta larval mortality compared to CrleGV-SA alone. A one-way ANOVA was performed to assess differences among the virus treatment groups, concluding that no statistically significant differences were observed among the groups. The experiments in this study provided valuable insights for future research, particularly in exploring the use of a protein-virus combination as a novel method for pest control. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Muleya, Naho
- Date: 2024-10-11
- Subjects: Cryptophlebia leucotreta Biological control , False Codling Moth , Cryptophlebia leucotreta granulovirus , Cryptophlebia peltastica nucleopolyhedrovirus , Citrus Diseases and pests South Africa , Baculoviruses
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463919 , vital:76457
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a significant pest native to Africa, causing damage to citrus and posing a threat to the export of fresh citrus in South Africa. Classified as a phytosanitary risk by several South African export markets, this pest necessitates effective control measures. Baculoviruses emerge as promising biological control agents against T. leucotreta due to their inherent safety and eco-friendly characteristics. Among these, Cryptophlebia leucotreta Granulovirus (CrleGV-SA) and Cryptophlebia peltastica Nucleopolyhedrovirus (CrpeNPV) stand out, both causing larval mortality upon infecting T. leucotreta. CrleGV-SA has been formulated into the products Cryptogran™, CryptoMax™ and Cryptex®, while CrpeNPV has been formulated into the product Multimax™. Both viruses are used in integrated pest management programmes to reduce fruit damage in agricultural fields, with CrleGV-SA having been employed against T. leucotreta for nearly 20 years in South Africa. However, these control options are limited by factors such as virulence and the slow speed of kill. This limitation can be addressed by exploiting potential synergistic relationships between baculoviruses infecting the same host. Previous studies have demonstrated that the truncated CpGV gp37 can enhance the infectivity of NPVs on other lepidopteran pests, such as Spodoptera exigua (Hübner). Although the mechanism behind this phenomenon remains unclear, it presents an opportunity to enhance the effectiveness of baculovirus-based management strategies. Notably, the genome of CrpeNPV encodes gp37, while CrleGV-SA lacks this gene. The potential interaction between CrleGV-SA and CrpeNPV gp37 remains unexplored. Therefore, investigating whether they exhibit synergistic or antagonistic effects is essential for optimising baculovirus-based management of T. leucotreta. This study aims to express CrpeNPV gp37 in a bacterial system and then evaluate its effect on larval mortality when combined with CrleGV-SA in laboratory bioassays. The initial step involved extracting genomic DNA (gDNA) from occlusion bodies (OBs) of CrpeNPV. A modified Quick DNA Miniprep plus kit was utilised, which entailed pre-treatment with Na2CO3 followed by neutralisation with Tris-HCI before gDNA extraction using the kit. Subsequently, the concentration of the gDNA was estimated using a Nanodrop spectrophotometer. Oligonucleotides targeting the CrpeNPV gp37 gene were designed for PCR amplification, with the gDNA serving as a template. The gp37 amplicon was identified through agarose gel electrophoresis and then gel purified in preparation for cloning. Secondly, the purified PCR product was cloned into the intermediate vector pJET1.2/blunt and then subcloned into the bacterial expression vector pCA528 through DNA ligation. The construction of recombinant plasmids (pJET-gp37 and pCA-gp37) was conducted and verified using Colony PCR, plasmid extraction, restriction enzyme analysis, and Sanger sequencing. Thirdly, the recombinant protein (6×His-SUMO-gp37) was expressed and purified using Nickel affinity chromatography and analysed through SDS-PAGE and Western blot techniques. The expression of 6×His-SUMO-gp37 was carried out at both 25 °C and 18 °C. A time course induction study was conducted, inducing transformed cells for 0-, 3-, 5-, and 24-hours post induction (hpi). SDS-PAGE and Western blotting of samples collected at various time points revealed that 6×His-SUMO-gp37, approximately 42 kDa in size, was visible from 3 hpi, with maximal expression at 24 hpi. Solubility analysis of 6×His-SUMO-gp37 was performed at both temperatures, showing solubility at 18 °C but predominantly present in the insoluble fraction. The soluble protein was purified under native conditions, while the insoluble protein was purified under denaturing conditions. Despite being unable to elute 6×His-SUMO-gp37 under native conditions, successful elution was achieved under denaturing conditions, confirmed via Western blot analysis. No further experiments were conducted on the eluted 6×His-SUMO-gp37 under denaturing conditions. Lastly, a preliminary surface dose bioassay was conducted to evaluate the efficacy of pelleted bacteria expressing 6×His-SUMO-gp37 in combination with CrleGV-SA against T. leucotreta neonates. Two lethal concentration doses of CrleGV-SA were prepared: a low concentration (2.96×104 OBs/mL) capable of killing 40 % of the T. leucotreta population, and a high concentration (2.96×105 OBs/mL) capable of killing 90 % of the population. The target protein, 6×His-SUMO-gp37, and the control, pCA528, were obtained by lysing the cells, centrifuging the samples, and collecting the insoluble fractions in pellet form. These fractions were then resuspended in PBS and used as treatments in combination with the prepared CrleGV-SA concentration doses. The concentration of the pellets was estimated using a Nanodrop spectrophotometer by measuring the absorbance at 280 nm. The bioassay results revealed that the combination of 100 μg/mL of pelleted bacteria expressing 6×His-SUMO-gp37 with CrleGV-SA had no effect on T. leucotreta larval mortality compared to CrleGV-SA alone. A one-way ANOVA was performed to assess differences among the virus treatment groups, concluding that no statistically significant differences were observed among the groups. The experiments in this study provided valuable insights for future research, particularly in exploring the use of a protein-virus combination as a novel method for pest control. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Computational search for nature-derived dual-action inhibitors of HIV-1 reverse transcriptase and integrase: a potential strategy to mitigate drug resistance progression
- Authors: Mwiinga, Luyando
- Date: 2024-10-11
- Subjects: HIV (Viruses) , Reverse transcriptase , Antiretroviral agents , RDKit , Drug resistance , Docking
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463930 , vital:76458
- Description: Human immunodeficiency virus Type 1 (HIV-1) is a devastating viral infection affecting millions worldwide and presents significant challenges in treatment and management. In 2022, approximately 39 million people were living with HIV with Sub-Saharan Africa having two thirds of these infections. Devastatingly, there were approximately 300 000 HIV/AIDS related deaths in Sub-Saharan Africa alone in 2022 alone. Antiretroviral therapy (ART) which is fundamental for HIV treatment, comprises of a combination of drugs such as nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTs), protease inhibitors (PIs) and integrase strand transfer inhibitors (INSTIs). However, although 28.7 million people out of the estimated 38.4 million people living with HIV in 2021 were receiving ART, the emergence of drug-resistant strains further complicates treatment efforts, highlighting the need for novel therapeutic approaches. This study aimed to address the challenges raised by drug resistance and significant side effects by identifying potential dual inhibitors against HIV-1 Reverse Transcriptase (RT) and Integrase (IN) using in silico techniques. RT RNase H and IN were chosen as targets for their shared dependency on Mg2+ ions within their active sites, which are crucial for catalytic activity. The selection of dual inhibitors was motivated by the fact that the virus would need to replicate at two points simultaneously to develop resistance, making it less likely. The objectives of this study included the creation of a natural derivative compound library using RDKit with the aid of SciFinder, utilizing (-)-epigallocatechin-3-O-gallate (EGCG), because of its dual inhibitory effects against RT and IN, as indicated by a study conducted by Sanna et al. 2019. The natural derivatives were chosen to take advantage of their chemical diversity and to explore potential novel therapeutic options for combating HIV drug resistance. The compound library created comprised of 125 203 compounds. Then docking studies were conducted to assess proteinligand binding. After the correlation of the RT and IN docking studies, 288 compounds were filtered to have potential dual inhibitory activity. Then quantitative estimation of druggability (QED) analysis identified three compounds with superior properties compared to EGCG and FDAapproved drug raltegravir (RAL). Molecular docking simulations revealed interactions between the inhibitors and the key active site residues of RT and IN, along with the chelation of at least one 3 Mg2+, suggesting the potential for enzymatic disruption. Furthermore, molecular dynamic (MD) simulations were then conducted to assess protein-ligand system behavior, through RMSD and RMSF analysis. The RMSD analysis uncovered instability in the IN-Sci30703 complex, leading to its exclusion as a potential dual action inhibitor. RMSF analysis for IN showed that all the inhibitors had the ability to limit the flexibility of the catalytic loop which is essential for catalytic activity. Therefore, further in vitro studies are required to evaluate the effectiveness of the remaining two EGCG derivatives (Sci33211 and Sci48919) in inhibiting RT and IN through the chelation of at least one Mg2+ ion to determine if they have superior dual inhibitory effects compared to EGCG. This study adds to the ongoing efforts to develop effective strategies against HIV-1 drug resistance and emphasizes the importance of continued research in this field. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mwiinga, Luyando
- Date: 2024-10-11
- Subjects: HIV (Viruses) , Reverse transcriptase , Antiretroviral agents , RDKit , Drug resistance , Docking
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463930 , vital:76458
- Description: Human immunodeficiency virus Type 1 (HIV-1) is a devastating viral infection affecting millions worldwide and presents significant challenges in treatment and management. In 2022, approximately 39 million people were living with HIV with Sub-Saharan Africa having two thirds of these infections. Devastatingly, there were approximately 300 000 HIV/AIDS related deaths in Sub-Saharan Africa alone in 2022 alone. Antiretroviral therapy (ART) which is fundamental for HIV treatment, comprises of a combination of drugs such as nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTs), protease inhibitors (PIs) and integrase strand transfer inhibitors (INSTIs). However, although 28.7 million people out of the estimated 38.4 million people living with HIV in 2021 were receiving ART, the emergence of drug-resistant strains further complicates treatment efforts, highlighting the need for novel therapeutic approaches. This study aimed to address the challenges raised by drug resistance and significant side effects by identifying potential dual inhibitors against HIV-1 Reverse Transcriptase (RT) and Integrase (IN) using in silico techniques. RT RNase H and IN were chosen as targets for their shared dependency on Mg2+ ions within their active sites, which are crucial for catalytic activity. The selection of dual inhibitors was motivated by the fact that the virus would need to replicate at two points simultaneously to develop resistance, making it less likely. The objectives of this study included the creation of a natural derivative compound library using RDKit with the aid of SciFinder, utilizing (-)-epigallocatechin-3-O-gallate (EGCG), because of its dual inhibitory effects against RT and IN, as indicated by a study conducted by Sanna et al. 2019. The natural derivatives were chosen to take advantage of their chemical diversity and to explore potential novel therapeutic options for combating HIV drug resistance. The compound library created comprised of 125 203 compounds. Then docking studies were conducted to assess proteinligand binding. After the correlation of the RT and IN docking studies, 288 compounds were filtered to have potential dual inhibitory activity. Then quantitative estimation of druggability (QED) analysis identified three compounds with superior properties compared to EGCG and FDAapproved drug raltegravir (RAL). Molecular docking simulations revealed interactions between the inhibitors and the key active site residues of RT and IN, along with the chelation of at least one 3 Mg2+, suggesting the potential for enzymatic disruption. Furthermore, molecular dynamic (MD) simulations were then conducted to assess protein-ligand system behavior, through RMSD and RMSF analysis. The RMSD analysis uncovered instability in the IN-Sci30703 complex, leading to its exclusion as a potential dual action inhibitor. RMSF analysis for IN showed that all the inhibitors had the ability to limit the flexibility of the catalytic loop which is essential for catalytic activity. Therefore, further in vitro studies are required to evaluate the effectiveness of the remaining two EGCG derivatives (Sci33211 and Sci48919) in inhibiting RT and IN through the chelation of at least one Mg2+ ion to determine if they have superior dual inhibitory effects compared to EGCG. This study adds to the ongoing efforts to develop effective strategies against HIV-1 drug resistance and emphasizes the importance of continued research in this field. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
The effect of biological control on the population dynamics of Pontederia crassipes Mart. (Pontederiaceae) and Salvinia minima Baker (Salviniales: Salviniaceae)
- Authors: Chikodza, Tressia
- Date: 2024-10-11
- Subjects: Pontederia crassipes , Salvinia minima , Pontederiaceae Biological control South Africa , Salviniaceae Biological control South Africa , Population dynamics , Secondary invasion
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464462 , vital:76513
- Description: Pontederia crassipes is widely regarded as the most damaging floating aquatic weed in terms of its invasive traits, and its impact on aquatic ecosystems. Biological control using host-specific natural enemies is widely used for its control, with the most recent agent released being a planthopper, Megamelus scutellaris, in South Africa and the USA. In South Africa, inundative releases of M. scutellaris have been shown to control the weed even at eutrophic, and high elevation cold sites, such as Hartbeespoort Dam, arguably Africa’s most hypertrophic impoundment. However, subsequent to the control of P. crassipes on Hartbeespoort Dam, in 2021, a secondary invader, Salvinia minima, dominated the water system. Salvinia minima is only known from a handful sites near Hartbeespoort Dam and there is currently no approved biocontrol agent for it. The population dynamics of P. crassipes and S. minima at the Dam were overall interchanging due to insect feeding on M. scutellaris reducing P. crassipes populations thus allowing S. minima to become dominant. Intense feeding from M. scutellaris resulted in the reduction of P. crassipes populations. During late autumn and winter, remaining P. crassipes plants experienced frost damage from cold temperatures. The decrease in P. crassipes allowed S. minima to successfully invade, potentially as the result of less competition from P. crassipes, and therefore available resources, such as space, nutrients, and light. However, as spring approached, P. crassipes regenerated from its seed bank, and S. minima populations diminished. The changes in dominance were observed in 2021 and 2022 but in 2023, this trend was not evident as S. minima did not dominate as in previous years. This thesis investigated the combination of competition and herbivory by M. scutellaris on the vigour of P. crassipes and S. minima to understand the dynamics of these two highly invasive species. Competitive abilities of P. crassipes and S. minima were determined using an inverse linear model with plant weight as the yield variable. In the absence of herbivory, P. crassipes, was 4 times more competitive than S. minima, but as competitive when exposed to M. scutellaris feeding. Salvinia minima was 1.2 times as aggressive as P. crassipes in the absence of herbivory, but 2.6 times as competitive when M. scutellaris was established on P. crassipes. In the presence of herbivory on P. crassipes, interspecific competition coefficients from P. crassipes on S. minima were no longer statistically significant. These results indicate that the competitive ability of P. crassipes was reduced through herbivory when grown with S. minima, explaining the temporal dominance between the two species at Hartbeespoort Dam. Some studies have reported that P. crassipes releases allelochemicals as a competitive strategy to algae and phytoplankton. Previously identified allelochemicals include N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine and linoleic acid. This thesis investigated the presence or absence of key chemical compounds released by P. crassipes during allelopathy with microbes and phytoplankton to determine its potential to inhibit S. minima growth. Methanol extracts from P. crassipes roots, leaves, and field samples underwent LC-ESI-MS/MS analysis, creating a molecular network to match chemical profiles. Of the investigated compounds, N-phenyl-1-naphthylamine and N-phenyl-2-naphthylamine were absent in P. crassipes and field samples, while linoleic acid was consistently found. Its presence suggests its potential defensive role against S. minima. Future research should explore allelochemical production in the presence of S. minima and algae to confirm if S. minima elicits an allelochemical response by P. crassipes, or whether the methods used here were insufficient to detect allelochemical production. Understanding whether P. crassipes employs allelochemicals, especially in the presence of S. minima, could shed light on its competitive advantage beyond its invasive nature at the Dam. , Thesis (MSc) -- Faculty of Science, Botany, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Chikodza, Tressia
- Date: 2024-10-11
- Subjects: Pontederia crassipes , Salvinia minima , Pontederiaceae Biological control South Africa , Salviniaceae Biological control South Africa , Population dynamics , Secondary invasion
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464462 , vital:76513
- Description: Pontederia crassipes is widely regarded as the most damaging floating aquatic weed in terms of its invasive traits, and its impact on aquatic ecosystems. Biological control using host-specific natural enemies is widely used for its control, with the most recent agent released being a planthopper, Megamelus scutellaris, in South Africa and the USA. In South Africa, inundative releases of M. scutellaris have been shown to control the weed even at eutrophic, and high elevation cold sites, such as Hartbeespoort Dam, arguably Africa’s most hypertrophic impoundment. However, subsequent to the control of P. crassipes on Hartbeespoort Dam, in 2021, a secondary invader, Salvinia minima, dominated the water system. Salvinia minima is only known from a handful sites near Hartbeespoort Dam and there is currently no approved biocontrol agent for it. The population dynamics of P. crassipes and S. minima at the Dam were overall interchanging due to insect feeding on M. scutellaris reducing P. crassipes populations thus allowing S. minima to become dominant. Intense feeding from M. scutellaris resulted in the reduction of P. crassipes populations. During late autumn and winter, remaining P. crassipes plants experienced frost damage from cold temperatures. The decrease in P. crassipes allowed S. minima to successfully invade, potentially as the result of less competition from P. crassipes, and therefore available resources, such as space, nutrients, and light. However, as spring approached, P. crassipes regenerated from its seed bank, and S. minima populations diminished. The changes in dominance were observed in 2021 and 2022 but in 2023, this trend was not evident as S. minima did not dominate as in previous years. This thesis investigated the combination of competition and herbivory by M. scutellaris on the vigour of P. crassipes and S. minima to understand the dynamics of these two highly invasive species. Competitive abilities of P. crassipes and S. minima were determined using an inverse linear model with plant weight as the yield variable. In the absence of herbivory, P. crassipes, was 4 times more competitive than S. minima, but as competitive when exposed to M. scutellaris feeding. Salvinia minima was 1.2 times as aggressive as P. crassipes in the absence of herbivory, but 2.6 times as competitive when M. scutellaris was established on P. crassipes. In the presence of herbivory on P. crassipes, interspecific competition coefficients from P. crassipes on S. minima were no longer statistically significant. These results indicate that the competitive ability of P. crassipes was reduced through herbivory when grown with S. minima, explaining the temporal dominance between the two species at Hartbeespoort Dam. Some studies have reported that P. crassipes releases allelochemicals as a competitive strategy to algae and phytoplankton. Previously identified allelochemicals include N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine and linoleic acid. This thesis investigated the presence or absence of key chemical compounds released by P. crassipes during allelopathy with microbes and phytoplankton to determine its potential to inhibit S. minima growth. Methanol extracts from P. crassipes roots, leaves, and field samples underwent LC-ESI-MS/MS analysis, creating a molecular network to match chemical profiles. Of the investigated compounds, N-phenyl-1-naphthylamine and N-phenyl-2-naphthylamine were absent in P. crassipes and field samples, while linoleic acid was consistently found. Its presence suggests its potential defensive role against S. minima. Future research should explore allelochemical production in the presence of S. minima and algae to confirm if S. minima elicits an allelochemical response by P. crassipes, or whether the methods used here were insufficient to detect allelochemical production. Understanding whether P. crassipes employs allelochemicals, especially in the presence of S. minima, could shed light on its competitive advantage beyond its invasive nature at the Dam. , Thesis (MSc) -- Faculty of Science, Botany, 2024
- Full Text:
- Date Issued: 2024-10-11
Exploring food waste narratives and perceptions in print media and in the urban community of Makhanda, in the Eastern Cape, South Africa
- Authors: Dlamini, Zinhle Nkululeko
- Date: 2024-10-11
- Subjects: Food waste South Africa Makhanda , Agenda-setting theory , Sociocultural system , Makhanda (South Africa) Social conditions , Mass media and public opinion South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464798 , vital:76546
- Description: Food waste (FW) is a global issue that has gained increasing attention in recent decades. There has been more research to identify the multi-layered causes and effects of this issue. A vast number of studies focus on the quantification of FW, its drivers, and causes. While quantifying the amount of FW being generated is important in revealing the scope of the problem, there are many aspects of FW that are still not as widely covered i.e., the socio-cultural component of FW. This is because first and foremost what is considered food, and what is considered FW is influenced by the sociocultural context in which it is obtained, prepared, and consumed. The socio-cultural context of a society cannot be studied properly without looking at the way the people that practice those specific societal norms and cultural practices think and perceive things. Perceptions are important because sociocultural behaviours and practices tend to be reproduced in correlation to how they are perceived. Thus, if the socio-cultural dimension of FW is to be dissected, one needs to look at the socialisation agents that affect the cultural context. A socialisation agent that has been cited as growing in influence and enjoying unprecedented access in human society is the media. Despite the proven influence of the media on perceptions and behavioural patterns, the sheer volume of studies that look at the linkages between media and topics such as FW is limited. in the context of the Global South, particularly in South Africa. In response to this research gap, I set out to examine the types of narratives and perceptions that print media and media consumers within an urban community have about FW. Since the study is centred around print media perceptions and narratives and those of the community, the study used a mixed-method approach that comprised of a media analysis, one-onone, semi structured interviews, key informant discussions as well as food focus groups. Thirty six respondents were interviewed with semi-structured one on one interviews, a further six respondents were key informants, they too were interviewed with one on one semi-structured interviews. Lastly, 16 were participants in the focus sessions, and each session comprised of 8 randomly selected participants. To procure the FW perceptions and narratives of print media and the people of Makhanda, the study was divided into three phases. Phase one comprised of a print media analysis through an archival media platform of SABINET. Phase two comprised of two food focus group sessions; phase three of the study comprised of the semi-structured interviews with 36 interviewees representing the general public and six with key informants. To make sense of the results obtained from the print media analysis, the study used the agenda setting framework and found that that the representation of FW content in print media was limited. Through the use of thematic analysis, 14 viii FW perceptions and narratives were identified in print media (and perceptions and narratives are used interchangeably, therefore 14 themes equals 14 FW perceptions and narratives). Of these 14 themes there were some that were more frequently presented than others. The most frequently presented perceptions and narratives in print media were the FW and food insecurity/hunger, FW and morality and FW and the economy. The study also found that a bulk of the FW content disseminated by print media belonged to a relatively few publications namely: Cape Argus, The Star, the Mail and Gurdian and the Daily Dispatch. These findings reinforced that FW perceptions and narratives in print media were not only disproportionally represented but were also disseminated by a limited pool of media content creators. The study found that Makhanda respondents used and preferred other media forms outside of print media i.e., radio and television. Respondents maintained that the media form they were the least exposed to and least preferred was print media (newspapers). From the 58 respondents, only seven respondents indicated that they listened to and preferred radio more than any other media form, and only two respondents noted that they read newspapers. In contrast, 24 respondents noted that they preferred and were more exposed to television than any other media form. In addition, respondents noted that they saw and heard a limited amount of FW content on the media that they were most exposed to. Instead, they noted that they were more exposed to content that encouraged them to procure and consume food, such as food advertisements. On average, individuals that were exposed to and preferred radio reported to hearing more FW content as opposed to individuals that preferred television. For instance, from the seven respondents that preferred and were most exposed to radio, four of them noted that they had heard a lot of FW content. While 17 of the 24 respondents that preferred and were most exposed to television, maintained that they did not recall seeing any FW content. The study also found that Makhanda respondents had a number of perceptions and narratives about FW, that were converted into themes using content and thematic analysis. The study found that Makhanda respondents had a total of 15 FW perceptions and narratives. Just like in the media analysis there were some perceptions and narratives that were emphasised and more frequently mentioned than others. The three most dominant themes were: affluence, FW and hunger, and FW and morality. Furthermore, the research also found that the perceptions and narratives of respondents were influenced by a variety of external and internal factors such as socio-economic status/affluence, gender, age, race, and media preference. These factors interacted with each other and varied in their significance from one respondent to the other. By far, the aspect shown to be the most influential in shaping respondents FW perceptions and narratives was affluence. Twentyeight respondents spoke about the economic drawbacks of FW and cited as reason for not engaging viii in FW. In addition to this, there were some respondents that maintained that FW did not occur amongst people who belonged to the lower socio-economic class and that rather, the phenomena were limited to those who were more affluent. In speaking about affluence, respondents e linked FW with other aspects such as race, gender, age, and media preference. For instance, in addition to claiming that FW was only limited to affluent households, other respondents felt that wasting food was a luxury the only white people participated in. Such claims highlight the idea that the sociocultural historical context of South Africa is one that has some influence in the FW perceptions and narratives of Makhanda respondents. The study found that there was little overlap in the types of perceptions and narratives that print media and the Makhanda respondents have about FW. From the 14 and 15 perceptions and narratives found between each realm there were only three thematic overlaps namely: the theme of affluence, morality and FW and food insecurity. This limited overlap of perceptions and narratives suggest that there is a disconnection present between the perceptions and narratives of print media and those that are exhibited by Makhanda respondents. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Dlamini, Zinhle Nkululeko
- Date: 2024-10-11
- Subjects: Food waste South Africa Makhanda , Agenda-setting theory , Sociocultural system , Makhanda (South Africa) Social conditions , Mass media and public opinion South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464798 , vital:76546
- Description: Food waste (FW) is a global issue that has gained increasing attention in recent decades. There has been more research to identify the multi-layered causes and effects of this issue. A vast number of studies focus on the quantification of FW, its drivers, and causes. While quantifying the amount of FW being generated is important in revealing the scope of the problem, there are many aspects of FW that are still not as widely covered i.e., the socio-cultural component of FW. This is because first and foremost what is considered food, and what is considered FW is influenced by the sociocultural context in which it is obtained, prepared, and consumed. The socio-cultural context of a society cannot be studied properly without looking at the way the people that practice those specific societal norms and cultural practices think and perceive things. Perceptions are important because sociocultural behaviours and practices tend to be reproduced in correlation to how they are perceived. Thus, if the socio-cultural dimension of FW is to be dissected, one needs to look at the socialisation agents that affect the cultural context. A socialisation agent that has been cited as growing in influence and enjoying unprecedented access in human society is the media. Despite the proven influence of the media on perceptions and behavioural patterns, the sheer volume of studies that look at the linkages between media and topics such as FW is limited. in the context of the Global South, particularly in South Africa. In response to this research gap, I set out to examine the types of narratives and perceptions that print media and media consumers within an urban community have about FW. Since the study is centred around print media perceptions and narratives and those of the community, the study used a mixed-method approach that comprised of a media analysis, one-onone, semi structured interviews, key informant discussions as well as food focus groups. Thirty six respondents were interviewed with semi-structured one on one interviews, a further six respondents were key informants, they too were interviewed with one on one semi-structured interviews. Lastly, 16 were participants in the focus sessions, and each session comprised of 8 randomly selected participants. To procure the FW perceptions and narratives of print media and the people of Makhanda, the study was divided into three phases. Phase one comprised of a print media analysis through an archival media platform of SABINET. Phase two comprised of two food focus group sessions; phase three of the study comprised of the semi-structured interviews with 36 interviewees representing the general public and six with key informants. To make sense of the results obtained from the print media analysis, the study used the agenda setting framework and found that that the representation of FW content in print media was limited. Through the use of thematic analysis, 14 viii FW perceptions and narratives were identified in print media (and perceptions and narratives are used interchangeably, therefore 14 themes equals 14 FW perceptions and narratives). Of these 14 themes there were some that were more frequently presented than others. The most frequently presented perceptions and narratives in print media were the FW and food insecurity/hunger, FW and morality and FW and the economy. The study also found that a bulk of the FW content disseminated by print media belonged to a relatively few publications namely: Cape Argus, The Star, the Mail and Gurdian and the Daily Dispatch. These findings reinforced that FW perceptions and narratives in print media were not only disproportionally represented but were also disseminated by a limited pool of media content creators. The study found that Makhanda respondents used and preferred other media forms outside of print media i.e., radio and television. Respondents maintained that the media form they were the least exposed to and least preferred was print media (newspapers). From the 58 respondents, only seven respondents indicated that they listened to and preferred radio more than any other media form, and only two respondents noted that they read newspapers. In contrast, 24 respondents noted that they preferred and were more exposed to television than any other media form. In addition, respondents noted that they saw and heard a limited amount of FW content on the media that they were most exposed to. Instead, they noted that they were more exposed to content that encouraged them to procure and consume food, such as food advertisements. On average, individuals that were exposed to and preferred radio reported to hearing more FW content as opposed to individuals that preferred television. For instance, from the seven respondents that preferred and were most exposed to radio, four of them noted that they had heard a lot of FW content. While 17 of the 24 respondents that preferred and were most exposed to television, maintained that they did not recall seeing any FW content. The study also found that Makhanda respondents had a number of perceptions and narratives about FW, that were converted into themes using content and thematic analysis. The study found that Makhanda respondents had a total of 15 FW perceptions and narratives. Just like in the media analysis there were some perceptions and narratives that were emphasised and more frequently mentioned than others. The three most dominant themes were: affluence, FW and hunger, and FW and morality. Furthermore, the research also found that the perceptions and narratives of respondents were influenced by a variety of external and internal factors such as socio-economic status/affluence, gender, age, race, and media preference. These factors interacted with each other and varied in their significance from one respondent to the other. By far, the aspect shown to be the most influential in shaping respondents FW perceptions and narratives was affluence. Twentyeight respondents spoke about the economic drawbacks of FW and cited as reason for not engaging viii in FW. In addition to this, there were some respondents that maintained that FW did not occur amongst people who belonged to the lower socio-economic class and that rather, the phenomena were limited to those who were more affluent. In speaking about affluence, respondents e linked FW with other aspects such as race, gender, age, and media preference. For instance, in addition to claiming that FW was only limited to affluent households, other respondents felt that wasting food was a luxury the only white people participated in. Such claims highlight the idea that the sociocultural historical context of South Africa is one that has some influence in the FW perceptions and narratives of Makhanda respondents. The study found that there was little overlap in the types of perceptions and narratives that print media and the Makhanda respondents have about FW. From the 14 and 15 perceptions and narratives found between each realm there were only three thematic overlaps namely: the theme of affluence, morality and FW and food insecurity. This limited overlap of perceptions and narratives suggest that there is a disconnection present between the perceptions and narratives of print media and those that are exhibited by Makhanda respondents. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
The assessment of abandoned cultivated lands: a case study of Lower Tsitsana and Hlankomo villages in the Tsitsa River catchment, Eastern Cape, South Africa
- Authors: Dakie, Regina Nokufa
- Date: 2024-10-11
- Subjects: Agricultural land , Grasslands South Africa Eastern Cape , Abandoned land , Social ecology , Aerial photography
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464787 , vital:76545
- Description: Globally, agriculture is an essential part of people’s livelihoods, contributing to rural economies and food security. However, cultivated land abandonment, the intentional or unintentional cessation of agricultural activities for takeover by other land uses, is becoming increasingly common. Although widely studied, the outcomes of cultivated land abandonment are highly context-dependent and varied. Understanding this phenomenon would thus benefit from placed-based social-ecological case study perspectives, particularly in more understudied contexts. This study represents such a perspective, taking a social-ecological approach to understand how land abandonment has emerged and what its consequences are for the desired future outcomes in the Hlankomo and Lower Tsitsana villages in the Tsitsa River catchment. Drawing on McGinnis & Ostrom’s (2009) framework, I framed cultivated land abandonment in my study area as a “focal action situation” informed by the interaction of natural resource systems, governance systems, actors, and resource units. To better understand the current state of the natural resource system and important ecological (resource) units (grass), I used two measures of ecological condition: a rapid assessment test that provided a broad, if superficial, understanding of degradation and land condition, and a veld condition assessment that provided an understanding of grassland composition and quality in abandoned fields. I also used aerial photographs to assess the extent of changes in abandoned cultivation in the catchment. To understand actors, governance systems, how they interacted with natural resource systems and units for land abandonment to emerge, and what implications these interactions may have for the future of these lands, I used semi-structured interviews. The Rapid Assessment Test tool showed that the abandoned cultivated fields were dominated by grasses (58.3%), while shrubs (11%) and succulents (11%) were the least prevalent. The veld assessment identified sixteen grass species in both villages, with Aristida junciformis (23%) and Eragrostis plana (22.2 %) being the most dominant. The grazing statuses of the grasses showed that there were more Increaser II species, followed by Increaser III, Exotic, Increaser I and Decreaser species, respectively. There were more grass species with low grazing and average grazing values than grass species with high grazing values. The Rapid Assessment tool and the Veld assessment showed that the fields were dominated by poor grass species that grow on degraded lands. The results thus showed that the abandoned cultivated lands are degraded and in poor condition, as they are covered mainly by poor grass species that are dominant in over-utilised and overgrazed areas. The aerial photographs showed a decline in cultivated lands from 1966 to 2015, with a significant decline between 1966 and 2003. The land under cultivation between 1966 and 2003 decreased by 95 %, resulting in an annual decline of 2.56 %. The land under cultivation from 2003 and 2015 decreased by 60 %, resulting in a decline of 4 % per year. Local people corroborated the increase in cultivated land abandonment in the interviews, and this is why I attempt to understand why abandoned cultivated land happened (how the resource system and governance systems/actors interacted to shape cultivated land abandonment). As in other South African rural contexts, reasons people gave for land cultivation abandonment revealed the strongly intertwined nature of ecological and social systems, including no fence, livestock eating crops, no cattle, lack of labour, migration, lack of resources (money and equipment), parents passing on, expensive fertilizers, rainfall variability, dependency on grants, lack of interest and laziness. People had different views about the future of the abandoned cultivated lands, suggesting building homes, recreational parks, poultry farms, and recultivating and livestock protection camps, while others indicated that they didn’t care what happens to the abandoned fields. Many people still value abandoned lands and would prefer for the land to be recultivated, but they are held back by factors beyond their control, such as no fencing and a lack of governmental support in the form of fertilisers and machinery for ploughing. Additionally, our ecological results suggest that, due to the degraded states of these lands, significant rehabilitation would be required to realize these desired outcomes. Overall, this study shows the social-ecological complexity that drives cultivated land abandonment in the Tsitsa River catchment, providing a context-specific understanding of the drivers and consequences of abandoned cultivated land, future options more specific to these villages, and the broader Tsitsa catchment. At the same time, my study also corroborates similar studies in rural African and other global South contexts, thus supporting generalizable knowledge that can be used in the development of agrarian, social and environmental policies in these regions. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Dakie, Regina Nokufa
- Date: 2024-10-11
- Subjects: Agricultural land , Grasslands South Africa Eastern Cape , Abandoned land , Social ecology , Aerial photography
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464787 , vital:76545
- Description: Globally, agriculture is an essential part of people’s livelihoods, contributing to rural economies and food security. However, cultivated land abandonment, the intentional or unintentional cessation of agricultural activities for takeover by other land uses, is becoming increasingly common. Although widely studied, the outcomes of cultivated land abandonment are highly context-dependent and varied. Understanding this phenomenon would thus benefit from placed-based social-ecological case study perspectives, particularly in more understudied contexts. This study represents such a perspective, taking a social-ecological approach to understand how land abandonment has emerged and what its consequences are for the desired future outcomes in the Hlankomo and Lower Tsitsana villages in the Tsitsa River catchment. Drawing on McGinnis & Ostrom’s (2009) framework, I framed cultivated land abandonment in my study area as a “focal action situation” informed by the interaction of natural resource systems, governance systems, actors, and resource units. To better understand the current state of the natural resource system and important ecological (resource) units (grass), I used two measures of ecological condition: a rapid assessment test that provided a broad, if superficial, understanding of degradation and land condition, and a veld condition assessment that provided an understanding of grassland composition and quality in abandoned fields. I also used aerial photographs to assess the extent of changes in abandoned cultivation in the catchment. To understand actors, governance systems, how they interacted with natural resource systems and units for land abandonment to emerge, and what implications these interactions may have for the future of these lands, I used semi-structured interviews. The Rapid Assessment Test tool showed that the abandoned cultivated fields were dominated by grasses (58.3%), while shrubs (11%) and succulents (11%) were the least prevalent. The veld assessment identified sixteen grass species in both villages, with Aristida junciformis (23%) and Eragrostis plana (22.2 %) being the most dominant. The grazing statuses of the grasses showed that there were more Increaser II species, followed by Increaser III, Exotic, Increaser I and Decreaser species, respectively. There were more grass species with low grazing and average grazing values than grass species with high grazing values. The Rapid Assessment tool and the Veld assessment showed that the fields were dominated by poor grass species that grow on degraded lands. The results thus showed that the abandoned cultivated lands are degraded and in poor condition, as they are covered mainly by poor grass species that are dominant in over-utilised and overgrazed areas. The aerial photographs showed a decline in cultivated lands from 1966 to 2015, with a significant decline between 1966 and 2003. The land under cultivation between 1966 and 2003 decreased by 95 %, resulting in an annual decline of 2.56 %. The land under cultivation from 2003 and 2015 decreased by 60 %, resulting in a decline of 4 % per year. Local people corroborated the increase in cultivated land abandonment in the interviews, and this is why I attempt to understand why abandoned cultivated land happened (how the resource system and governance systems/actors interacted to shape cultivated land abandonment). As in other South African rural contexts, reasons people gave for land cultivation abandonment revealed the strongly intertwined nature of ecological and social systems, including no fence, livestock eating crops, no cattle, lack of labour, migration, lack of resources (money and equipment), parents passing on, expensive fertilizers, rainfall variability, dependency on grants, lack of interest and laziness. People had different views about the future of the abandoned cultivated lands, suggesting building homes, recreational parks, poultry farms, and recultivating and livestock protection camps, while others indicated that they didn’t care what happens to the abandoned fields. Many people still value abandoned lands and would prefer for the land to be recultivated, but they are held back by factors beyond their control, such as no fencing and a lack of governmental support in the form of fertilisers and machinery for ploughing. Additionally, our ecological results suggest that, due to the degraded states of these lands, significant rehabilitation would be required to realize these desired outcomes. Overall, this study shows the social-ecological complexity that drives cultivated land abandonment in the Tsitsa River catchment, providing a context-specific understanding of the drivers and consequences of abandoned cultivated land, future options more specific to these villages, and the broader Tsitsa catchment. At the same time, my study also corroborates similar studies in rural African and other global South contexts, thus supporting generalizable knowledge that can be used in the development of agrarian, social and environmental policies in these regions. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Investigating optoelectronic and thermal properties of perylene tetracarboxylic bisimide derivatives-and-cellulose nanocomposites for possible solar energy applications
- Ndwandwe, Bongeka Lethukukhanya
- Authors: Ndwandwe, Bongeka Lethukukhanya
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464554 , vital:76521
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ndwandwe, Bongeka Lethukukhanya
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464554 , vital:76521
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Synthesis and biological evaluation of simple carboxylated chalcone and aurone derivatives
- Authors: Shauri, Thierry Lwanzo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464576 , vital:76523
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Shauri, Thierry Lwanzo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464576 , vital:76523
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Thermoluminescence and phototransferred thermoluminescence of annealed α-Al2O3:C
- Elago, Fiindje Elias Muliokela
- Authors: Elago, Fiindje Elias Muliokela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466688 , vital:76767
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Elago, Fiindje Elias Muliokela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466688 , vital:76767
- Description: Access restricted. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
Technological pedagogical content knowledge: an examination of rural secondary school life sciences teachers’ integration of technology in Eastern Cape province
- Authors: Shambare, Brian
- Date: 2024-10-11
- Subjects: Educational technology , Technological Pedagogical Content Knowledge , Science Study and teaching (Secondary) South Africa Easern Cape , Education, Rural South Africa Easern Cape , Educational sociology
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466458 , vital:76730 , DOI https://doi.org/10.21504/10962/466458
- Description: Rural education, particularly in the Global South, faces distinct challenges flowing from low socio-economic conditions, limited resources, and inadequate funding. These issues notably affect rural teachers’ abilities to deliver quality education. Although technology integration offers potential benefits and rural teachers have increased access to various technologies, they frequently adopt these tools spontaneously without guidelines. While many teachers in rural schools choose specific technologies to address teaching challenges, technology has to be integrated with a clear pedagogical intent. The rural teachers’ frequent adoption of technologies hints at technological pedagogical content knowledge (TPACK) development, consciously or unconsciously. However, the process of developing this expertise remains largely unknown. Furthermore, the development of TPACK among teachers in rural Global South schools, particularly those who did not receive formal or informal technology training during their initial teacher education or professional development, remains unclear. Therefore, this research delved into the practices, factors, and experiences influencing the development of TPACK, all from the perspective of Life Sciences teachers in rural schools. The voices of teachers in rural regions have been notably absent in the broader discourse of TPACK research, making the current study’s insights particularly significant. This qualitative and investigative study, located within the interpretivist paradigm, is grounded in Vygotsky’s (1978) socio-cultural theory and Koehler and Mishra’s (2006) Technological Pedagogical Content Knowledge framework. Seven Life Sciences teachers participated in the study. The teacher participants were purposively sampled from schools in the Joe Gqabi district in the Eastern Cape province of South Africa. Multiple data-generation instruments were employed. These included a questionnaire, semi-structured interviews, lesson observations, and sharing circle discussions. A thematic analysis approach, guided by the study’s dual theoretical perspective, was applied to dissect and analyse the data. The study’s findings challenged the prevailing assumption that rural schools lack access to technological resources, unveiling that rural Life Sciences teachers in this research had access to diverse educational technologies. Nevertheless, despite improved technology accessibility, these teachers predominantly employed ‘simple skill-based’ technologies for content delivery, resulting in limited learner engagement. Notwithstanding the challenges posed by inadequate school infrastructure, limited electricity access, and poor Internet connectivity, this investigation found that Life Sciences teachers in rural settings who lack formal technology integration training demonstrated enthusiasm for incorporating technology into their teaching methods. Furthermore, these teachers exhibited strength in non-technological TPACK domains, such as content knowledge (CK), pedagogical knowledge (PK), and pedagogical content knowledge (PCK), while demonstrating limited expertise in technology-related domains, such as technological knowledge (TK), technological pedagogical knowledge (TPK), and technological pedagogical content knowledge (TPACK). The study uncovered nuanced factors, practices, and experiences contributing to TPACK development among rural Life Sciences teachers. These include learning from their learners, collaborating with peers, and engaging in self-directed learning. The study also proposed a new theoretical perspective to the existing TPACK framework to cater for technology integration in rural school contexts. Overall, this research provided a unique perspective on TPACK development in rural schools, particularly in the Global South. The study recommended targeted investments in professional development, promoting peer collaboration, and fostering a culture of self-directed learning. Furthermore, the current research emphasised the importance of recognising the evolving educational landscape as a two-way knowledge exchange between teachers and learners to foster TPACK development in rural schools. , Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Shambare, Brian
- Date: 2024-10-11
- Subjects: Educational technology , Technological Pedagogical Content Knowledge , Science Study and teaching (Secondary) South Africa Easern Cape , Education, Rural South Africa Easern Cape , Educational sociology
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466458 , vital:76730 , DOI https://doi.org/10.21504/10962/466458
- Description: Rural education, particularly in the Global South, faces distinct challenges flowing from low socio-economic conditions, limited resources, and inadequate funding. These issues notably affect rural teachers’ abilities to deliver quality education. Although technology integration offers potential benefits and rural teachers have increased access to various technologies, they frequently adopt these tools spontaneously without guidelines. While many teachers in rural schools choose specific technologies to address teaching challenges, technology has to be integrated with a clear pedagogical intent. The rural teachers’ frequent adoption of technologies hints at technological pedagogical content knowledge (TPACK) development, consciously or unconsciously. However, the process of developing this expertise remains largely unknown. Furthermore, the development of TPACK among teachers in rural Global South schools, particularly those who did not receive formal or informal technology training during their initial teacher education or professional development, remains unclear. Therefore, this research delved into the practices, factors, and experiences influencing the development of TPACK, all from the perspective of Life Sciences teachers in rural schools. The voices of teachers in rural regions have been notably absent in the broader discourse of TPACK research, making the current study’s insights particularly significant. This qualitative and investigative study, located within the interpretivist paradigm, is grounded in Vygotsky’s (1978) socio-cultural theory and Koehler and Mishra’s (2006) Technological Pedagogical Content Knowledge framework. Seven Life Sciences teachers participated in the study. The teacher participants were purposively sampled from schools in the Joe Gqabi district in the Eastern Cape province of South Africa. Multiple data-generation instruments were employed. These included a questionnaire, semi-structured interviews, lesson observations, and sharing circle discussions. A thematic analysis approach, guided by the study’s dual theoretical perspective, was applied to dissect and analyse the data. The study’s findings challenged the prevailing assumption that rural schools lack access to technological resources, unveiling that rural Life Sciences teachers in this research had access to diverse educational technologies. Nevertheless, despite improved technology accessibility, these teachers predominantly employed ‘simple skill-based’ technologies for content delivery, resulting in limited learner engagement. Notwithstanding the challenges posed by inadequate school infrastructure, limited electricity access, and poor Internet connectivity, this investigation found that Life Sciences teachers in rural settings who lack formal technology integration training demonstrated enthusiasm for incorporating technology into their teaching methods. Furthermore, these teachers exhibited strength in non-technological TPACK domains, such as content knowledge (CK), pedagogical knowledge (PK), and pedagogical content knowledge (PCK), while demonstrating limited expertise in technology-related domains, such as technological knowledge (TK), technological pedagogical knowledge (TPK), and technological pedagogical content knowledge (TPACK). The study uncovered nuanced factors, practices, and experiences contributing to TPACK development among rural Life Sciences teachers. These include learning from their learners, collaborating with peers, and engaging in self-directed learning. The study also proposed a new theoretical perspective to the existing TPACK framework to cater for technology integration in rural school contexts. Overall, this research provided a unique perspective on TPACK development in rural schools, particularly in the Global South. The study recommended targeted investments in professional development, promoting peer collaboration, and fostering a culture of self-directed learning. Furthermore, the current research emphasised the importance of recognising the evolving educational landscape as a two-way knowledge exchange between teachers and learners to foster TPACK development in rural schools. , Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Exploring how visual models can be used in teaching mathematics for growing a productive disposition in Grade 9 learners
- Shetunyenga, Fillipus Shetunyenga
- Authors: Shetunyenga, Fillipus Shetunyenga
- Date: 2024-10-11
- Subjects: Visual learning , Mathematics Study and teaching (Secondary) Namibia , High school students Attitudes , Visualization , Constructivism (Education)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463625 , vital:76426
- Description: The Namibian Curriculum for Basic Education states clearly that Indigenous Knowledge (IK) should be integrated into science teaching. However, the irony is that it does not give clear pedagogical guidelines on how it should be integrated. The implication is that the curriculum assumes that all teachers are aware of how to integrate IK into their teaching. This assumption has therefore led to little or no integration of IK in many classrooms in Namibia, something which could be in part a contributing factor to poor learners’ academic performance in science subjects and Agricultural Science in particular. This tension in the curriculum plus the apparent gap in the literature regarding the integration of IK has triggered my interest to conduct this interventionist qualitative case study. Essentially, this study aimed to explore affordances and/or hindrances when using the indigenous technology of organic crop farming to mediate learning in Grade 12 Agricultural Science classes in peri-urban schools in the Oshana region in Namibia. The study was underpinned by the interpretivist and Ubuntu paradigms. Vygotsky’s (1978) socio-cultural theory and Shulman’s (1986) pedagogical content knowledge (PCK) framework were used as lenses to analyse my data. Within PCK, I also used Mavhunga and Rollnick’s (2013) Topic-Specific PCK as an analytical framework. The findings of the study revealed that the integration of Indigenous knowledge in Agricultural Science education has great potential in improving both the teaching and learnng of science. It also revealed that the Agricultural Science teachers were positive towards the integration of IK in their lessons. However, they conceded that they lacked pedagogical insights on how to integrate IK as they were never trained on how to integrate it. As a result, they found the presentations by the Indigenous Knowledge Custodians (IKCs) informative and shed light on how they could integrate IK during teaching and learning. That is, they became cultural knowledge brokers making science relevant and accessible to their learners. The study thus recommends that teacher training institutions should modify the curriculum to include a pedagogy course module on IK to equip students with the essential PCK on IK integration in science teaching. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Shetunyenga, Fillipus Shetunyenga
- Date: 2024-10-11
- Subjects: Visual learning , Mathematics Study and teaching (Secondary) Namibia , High school students Attitudes , Visualization , Constructivism (Education)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463625 , vital:76426
- Description: The Namibian Curriculum for Basic Education states clearly that Indigenous Knowledge (IK) should be integrated into science teaching. However, the irony is that it does not give clear pedagogical guidelines on how it should be integrated. The implication is that the curriculum assumes that all teachers are aware of how to integrate IK into their teaching. This assumption has therefore led to little or no integration of IK in many classrooms in Namibia, something which could be in part a contributing factor to poor learners’ academic performance in science subjects and Agricultural Science in particular. This tension in the curriculum plus the apparent gap in the literature regarding the integration of IK has triggered my interest to conduct this interventionist qualitative case study. Essentially, this study aimed to explore affordances and/or hindrances when using the indigenous technology of organic crop farming to mediate learning in Grade 12 Agricultural Science classes in peri-urban schools in the Oshana region in Namibia. The study was underpinned by the interpretivist and Ubuntu paradigms. Vygotsky’s (1978) socio-cultural theory and Shulman’s (1986) pedagogical content knowledge (PCK) framework were used as lenses to analyse my data. Within PCK, I also used Mavhunga and Rollnick’s (2013) Topic-Specific PCK as an analytical framework. The findings of the study revealed that the integration of Indigenous knowledge in Agricultural Science education has great potential in improving both the teaching and learnng of science. It also revealed that the Agricultural Science teachers were positive towards the integration of IK in their lessons. However, they conceded that they lacked pedagogical insights on how to integrate IK as they were never trained on how to integrate it. As a result, they found the presentations by the Indigenous Knowledge Custodians (IKCs) informative and shed light on how they could integrate IK during teaching and learning. That is, they became cultural knowledge brokers making science relevant and accessible to their learners. The study thus recommends that teacher training institutions should modify the curriculum to include a pedagogy course module on IK to equip students with the essential PCK on IK integration in science teaching. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11