Synthesis of indium phthalocyanines for photodynamic antimicrobial chemotherapy and photo-oxidation of pollutants
- Authors: Sindelo, Azole
- Date: 2019
- Subjects: Phthalocyanines , Azo dyes , Indium compounds , Photochemotherapy , Nanoparticles , Photodegradation , Pollutants , Water -- Purification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67581 , vital:29116
- Description: Indium (III) octacarboxyl phthalocyanine (ClInOCPc) alone and when conjugated to magnetic nanoparticles (MNP-ClInOCPc), 2(3),9(10),16(17),23(24)-octapyridylsulfanyl phthalocyaninato chloroindium (III) (ClInOPyPc) and its quaternized derivative 2(3),9(10),16(17),23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (ClInOMePyPc) were synthesized. All Pcs were tested for both photodynamic antimicrobial chemotherapy (PACT) of an unknown water sample and photo-degradation of methyl red (MR). The singlet quantum yield (ΦΔ) for the ClInOCPc and MNP-ClInOCPc in PAN polymer fibers were 0.36 and 0.20 respectively using ADMA as a quencher in water. The photo-inactivation of bacteria in a water sample with unknown microbes was tested, with the MNP-ClInOCPc inactivating 90.6 % of the microbes and the ClInOCPc with 84.8 %. When embedded to the polymer, there was 48% bacterial clearance for ClInOCPc and 64% clearance for the MNP-ClInOCPc. The rate of degradation of MR increased with decrease of the MR concentration, with the MNP-ClInOCPc having the fastest rate. For ClInOPyPc and ClInOMePyPc, the singlet quantum yields were 0.46 and 0.33 in dimethylformamide (DMF), respectively. The PACT activity of ClInOMePyPc (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium (III) triiodide (1) (containing 3 positive charges) and 2-[4-(N-methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (2) (containing 4 positive charges). When comparing ClInOMePyPc, 1 and 2, the largest log reduction for E. coli were obtained for complex 2 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
- Full Text:
- Date Issued: 2019
- Authors: Sindelo, Azole
- Date: 2019
- Subjects: Phthalocyanines , Azo dyes , Indium compounds , Photochemotherapy , Nanoparticles , Photodegradation , Pollutants , Water -- Purification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67581 , vital:29116
- Description: Indium (III) octacarboxyl phthalocyanine (ClInOCPc) alone and when conjugated to magnetic nanoparticles (MNP-ClInOCPc), 2(3),9(10),16(17),23(24)-octapyridylsulfanyl phthalocyaninato chloroindium (III) (ClInOPyPc) and its quaternized derivative 2(3),9(10),16(17),23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (ClInOMePyPc) were synthesized. All Pcs were tested for both photodynamic antimicrobial chemotherapy (PACT) of an unknown water sample and photo-degradation of methyl red (MR). The singlet quantum yield (ΦΔ) for the ClInOCPc and MNP-ClInOCPc in PAN polymer fibers were 0.36 and 0.20 respectively using ADMA as a quencher in water. The photo-inactivation of bacteria in a water sample with unknown microbes was tested, with the MNP-ClInOCPc inactivating 90.6 % of the microbes and the ClInOCPc with 84.8 %. When embedded to the polymer, there was 48% bacterial clearance for ClInOCPc and 64% clearance for the MNP-ClInOCPc. The rate of degradation of MR increased with decrease of the MR concentration, with the MNP-ClInOCPc having the fastest rate. For ClInOPyPc and ClInOMePyPc, the singlet quantum yields were 0.46 and 0.33 in dimethylformamide (DMF), respectively. The PACT activity of ClInOMePyPc (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium (III) triiodide (1) (containing 3 positive charges) and 2-[4-(N-methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (2) (containing 4 positive charges). When comparing ClInOMePyPc, 1 and 2, the largest log reduction for E. coli were obtained for complex 2 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
- Full Text:
- Date Issued: 2019
Synthesis of pH responsive carriers for pulmonary drug delivery of anti-tuberculosis therapeutics: mesoporous silica nanoparticles and gelatin nanoparticles
- Authors: Ngoepe, Mpho Phehello
- Date: 2019
- Subjects: Drug delivery systems , Pulmonary pharmacology , Nanosilicon , Nanomedicine , Nanoparticles , Mesoporous materials , Silica , Tuberculosis -- Treatment
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76519 , vital:30590
- Description: Pulmonary drug delivery has historically been used as a route for delivery of therapeutics for respiratory disease management. However, while there are many advantages, there are also some serious limitations, arising mostly from the physical aspects of the inhaler devices. This is more profound when the devices are the driving force for controlling particle size generation, which results in non-uniform particles that end up being swallowed/wasted/expelled. One promising solution to overcome this limitation is to pre-formulate nano/microscale particles with a high degree of manufacturing control. Nanomedicine has advanced such that there are already several nanoparticle formulations commercially available. In the case of tuberculosis treatment, there is an opportunity not only to examine the use of nanoparticles for inhalation therapy, but to take advantage of the fact that the physiochemical environment of diseased tissue is significantly different to health lung tissue (lower pH and increased enzyme concentrations). We formulated two series of nanoparticles, whose design included moieties that could respond to pH and enzymes. To address variability, a Box-Behnken statistical approach was followed to construct mesoporous silica nanoparticles. These “hard nanoparticles” can entrap both lipophilic and hydrophilic drugs and were coated with a pH-sensitive hydrazone linker. It was observed that pH, calcination temperature and ratio of water to silica source played the greatest role, not only in controlling the physicochemical properties of the nanoparticles but also the drug release rate. A second series of nanoparticles were synthesized based on gelatin. This was done partly to add support the comparison of hard (inorganic silica) versus soft, organic particles, but also to enable enzymatic degradation and drug release. Again, diseased lung tissue expresses increased concentrations of gelatinase enzymes that could be used to stimulate drug release at the site of the disease. In addition, it was observed that the non-ionic surfactant C12E10 could interact with the protein via hydrophobic interactions thus affecting the gelatin folding. The folding states affected crosslinking with the pH responsive linker, which in turn affected the rate of drug release. To support the synthetic work, we sought to develop a unique 3D lung model directly from MRI data of tuberculosis infected lungs. This would not only permit the evaluation of our nanoparticles but could be used as a proxy for in-vivo studies in future to predict lung deposition in diseased lung. Thus, this study shows that it is possible to synthesize pH and enzyme sensitive nanoparticles for pulmonary drug delivery in the treatment and management of pulmonary tuberculosis. These particles could be loaded with either hydrophobic or hydrophilic drugs and their distribution in the airway modelled using an in-silico 3D model based on real data. Further development and verification of these results should improve treatment for pulmonary diseases and conditions such as tuberculosis. This is especially urgent in the face of multi-drug resistance and poor side effects profiles for current treatment.
- Full Text:
- Date Issued: 2019
- Authors: Ngoepe, Mpho Phehello
- Date: 2019
- Subjects: Drug delivery systems , Pulmonary pharmacology , Nanosilicon , Nanomedicine , Nanoparticles , Mesoporous materials , Silica , Tuberculosis -- Treatment
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76519 , vital:30590
- Description: Pulmonary drug delivery has historically been used as a route for delivery of therapeutics for respiratory disease management. However, while there are many advantages, there are also some serious limitations, arising mostly from the physical aspects of the inhaler devices. This is more profound when the devices are the driving force for controlling particle size generation, which results in non-uniform particles that end up being swallowed/wasted/expelled. One promising solution to overcome this limitation is to pre-formulate nano/microscale particles with a high degree of manufacturing control. Nanomedicine has advanced such that there are already several nanoparticle formulations commercially available. In the case of tuberculosis treatment, there is an opportunity not only to examine the use of nanoparticles for inhalation therapy, but to take advantage of the fact that the physiochemical environment of diseased tissue is significantly different to health lung tissue (lower pH and increased enzyme concentrations). We formulated two series of nanoparticles, whose design included moieties that could respond to pH and enzymes. To address variability, a Box-Behnken statistical approach was followed to construct mesoporous silica nanoparticles. These “hard nanoparticles” can entrap both lipophilic and hydrophilic drugs and were coated with a pH-sensitive hydrazone linker. It was observed that pH, calcination temperature and ratio of water to silica source played the greatest role, not only in controlling the physicochemical properties of the nanoparticles but also the drug release rate. A second series of nanoparticles were synthesized based on gelatin. This was done partly to add support the comparison of hard (inorganic silica) versus soft, organic particles, but also to enable enzymatic degradation and drug release. Again, diseased lung tissue expresses increased concentrations of gelatinase enzymes that could be used to stimulate drug release at the site of the disease. In addition, it was observed that the non-ionic surfactant C12E10 could interact with the protein via hydrophobic interactions thus affecting the gelatin folding. The folding states affected crosslinking with the pH responsive linker, which in turn affected the rate of drug release. To support the synthetic work, we sought to develop a unique 3D lung model directly from MRI data of tuberculosis infected lungs. This would not only permit the evaluation of our nanoparticles but could be used as a proxy for in-vivo studies in future to predict lung deposition in diseased lung. Thus, this study shows that it is possible to synthesize pH and enzyme sensitive nanoparticles for pulmonary drug delivery in the treatment and management of pulmonary tuberculosis. These particles could be loaded with either hydrophobic or hydrophilic drugs and their distribution in the airway modelled using an in-silico 3D model based on real data. Further development and verification of these results should improve treatment for pulmonary diseases and conditions such as tuberculosis. This is especially urgent in the face of multi-drug resistance and poor side effects profiles for current treatment.
- Full Text:
- Date Issued: 2019
Synthesis, characterisation and spectroscopic studies of diazine-N-oxide complexes of iron(II) towards the development of sensors
- Authors: Mpiti, Unako Bongani
- Date: 2019
- Subjects: Diazines , Ligands , Iron
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/94753 , vital:31075
- Description: The characteristic magnetic and spectroscopic features associated with the red monomeric or dimeric, and polymeric pyrazine-N-oxide (PyzNO) iron(II) perchlorate complexes; Fen(μ1,1-pyzNO)2n-2(pyzNO)3n+2(ClO4)2n (n = {1, 2}*, and the novel compound {Fe(μ-pyzNO-κN,κO)n-1(pyzNO-κN)2(pyzNO-κO)2}n(ClO4)2n†, respectively, were investigated. These properties are altered substantially when the complexes are hydrated; for instance, by atmospheric exposure. The resulting species; Fe(pyzNO)5(H2O)3(ClO4)2* and [Fe(pyzNO-κN)4(H2O)2](ClO4)2.2H2O†, which have different hues of a bright yellow colour, were found to exhibit strong paramagnetism, in contrast to their anhydrous precursors, which are ‘EPR silent’. A low spin → high spin crossover (LS→HS, SCO) transition was therefore proposed to occur as the complexes become hydrated by atmospheric moisture. The red→yellow colour change is reversible, and dehydration of the yellow species by heating regenerates the red variant, a feature which lends itself to the potential applicability of the system as a sensor. Further emphasis on this potential derives from the fact that the hydration/dehydration process, and its accompanying physical changes, appears reversible even after many such treatments. It became of interest, then, to determine if these changes were limited to water-exposed samples, or if they occurred under more diverse solvent atmospheres. The reversibility of such exposure on the structure of the novel polynuclear complex was therefore investigated. In general, it was found that there occurred a strong solvent-complex association for the more polar solvents. Red→yellow, LS→HS events were seen when the complex was exposed to the vapours of p-dioxane, acetaldehyde and formaldehyde, and to a lesser extent, to that of methanol. In each case, significant structural changes were seen, as evidenced be comparative XRPD and thermo-analytical studies. Some of these changes have however been ascribed to the effects of partial dissolution upon extended exposure of the complex to the associated media. Exposure to less polar solvent atmospheres, such as those of cyclohexane, toluene, diethyl ether, etc., showed some signs of mild solvent surface adhesion, but were unaccompanied by discernible magnetic and colour changes. Another novel complex was produced during attempts to synthesize the PyzNO complexes from a mixture of a 2,2’-dimethoxypropane (DMP) and ethanol (1:1, v/v), rather than the methanol/DMP mixture which had been alternately used. The formula of the resulting complex is Fe(pyzNO)6(ClO4)2.3EtOH*. This EPR inactive product was orange in colour, and transformed into a bright yellow, strongly paramagnetic species upon atmospheric exposure. Further solvent studies showed that this species interacted significantly with all solvents tested, but generally more strongly with increasing solvent polarity. Orange→yellow colour changes occurred in environments saturated with p-dioxane, acetaldehyde and formaldehyde vapours. The DMSO-exposed sample transformed to dark red, due to suspected PyzNO substitution by the solvent. The red→yellow and orange→yellow colour changes were ascribed to the formal substitution of O-coordinated PyzNO (μ-PyzNO in the polymeric complex) by the incoming solvent. The resulting structural and geometric changes stimulated a redistribution of d electrons among the new constituent molecular orbitals of altered energy and symmetry. Therefore, although the colour changes were not conventionally solvatochromic - in that the original structure was lost on exposure – data suggested that it was the coordination of species of higher donor strength that produced the observed bathochromic shifts. A novel 4,4’-bipyridine-N-oxide Fe(II) perchlorate complex, Fe2(bipyNO)5(ClO4)4.6MeOH†, was also produced, primarily for physicochemical comparison with the PyzNO complexes. No colour or magnetic changes were seen on atmospheric exposure. The original complex was observed to be inherently paramagnetic, and no SCO events occurred upon solvent exposure. Despite this, thermal analyses showed that the complex did exhibit the strong uptake of polar solvents in general, but particularly with acetaldehyde. Significant structural changes upon exposure were limited to surface phenomena, with the exception of the acetaldehyde-exposed sample.
- Full Text:
- Date Issued: 2019
- Authors: Mpiti, Unako Bongani
- Date: 2019
- Subjects: Diazines , Ligands , Iron
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/94753 , vital:31075
- Description: The characteristic magnetic and spectroscopic features associated with the red monomeric or dimeric, and polymeric pyrazine-N-oxide (PyzNO) iron(II) perchlorate complexes; Fen(μ1,1-pyzNO)2n-2(pyzNO)3n+2(ClO4)2n (n = {1, 2}*, and the novel compound {Fe(μ-pyzNO-κN,κO)n-1(pyzNO-κN)2(pyzNO-κO)2}n(ClO4)2n†, respectively, were investigated. These properties are altered substantially when the complexes are hydrated; for instance, by atmospheric exposure. The resulting species; Fe(pyzNO)5(H2O)3(ClO4)2* and [Fe(pyzNO-κN)4(H2O)2](ClO4)2.2H2O†, which have different hues of a bright yellow colour, were found to exhibit strong paramagnetism, in contrast to their anhydrous precursors, which are ‘EPR silent’. A low spin → high spin crossover (LS→HS, SCO) transition was therefore proposed to occur as the complexes become hydrated by atmospheric moisture. The red→yellow colour change is reversible, and dehydration of the yellow species by heating regenerates the red variant, a feature which lends itself to the potential applicability of the system as a sensor. Further emphasis on this potential derives from the fact that the hydration/dehydration process, and its accompanying physical changes, appears reversible even after many such treatments. It became of interest, then, to determine if these changes were limited to water-exposed samples, or if they occurred under more diverse solvent atmospheres. The reversibility of such exposure on the structure of the novel polynuclear complex was therefore investigated. In general, it was found that there occurred a strong solvent-complex association for the more polar solvents. Red→yellow, LS→HS events were seen when the complex was exposed to the vapours of p-dioxane, acetaldehyde and formaldehyde, and to a lesser extent, to that of methanol. In each case, significant structural changes were seen, as evidenced be comparative XRPD and thermo-analytical studies. Some of these changes have however been ascribed to the effects of partial dissolution upon extended exposure of the complex to the associated media. Exposure to less polar solvent atmospheres, such as those of cyclohexane, toluene, diethyl ether, etc., showed some signs of mild solvent surface adhesion, but were unaccompanied by discernible magnetic and colour changes. Another novel complex was produced during attempts to synthesize the PyzNO complexes from a mixture of a 2,2’-dimethoxypropane (DMP) and ethanol (1:1, v/v), rather than the methanol/DMP mixture which had been alternately used. The formula of the resulting complex is Fe(pyzNO)6(ClO4)2.3EtOH*. This EPR inactive product was orange in colour, and transformed into a bright yellow, strongly paramagnetic species upon atmospheric exposure. Further solvent studies showed that this species interacted significantly with all solvents tested, but generally more strongly with increasing solvent polarity. Orange→yellow colour changes occurred in environments saturated with p-dioxane, acetaldehyde and formaldehyde vapours. The DMSO-exposed sample transformed to dark red, due to suspected PyzNO substitution by the solvent. The red→yellow and orange→yellow colour changes were ascribed to the formal substitution of O-coordinated PyzNO (μ-PyzNO in the polymeric complex) by the incoming solvent. The resulting structural and geometric changes stimulated a redistribution of d electrons among the new constituent molecular orbitals of altered energy and symmetry. Therefore, although the colour changes were not conventionally solvatochromic - in that the original structure was lost on exposure – data suggested that it was the coordination of species of higher donor strength that produced the observed bathochromic shifts. A novel 4,4’-bipyridine-N-oxide Fe(II) perchlorate complex, Fe2(bipyNO)5(ClO4)4.6MeOH†, was also produced, primarily for physicochemical comparison with the PyzNO complexes. No colour or magnetic changes were seen on atmospheric exposure. The original complex was observed to be inherently paramagnetic, and no SCO events occurred upon solvent exposure. Despite this, thermal analyses showed that the complex did exhibit the strong uptake of polar solvents in general, but particularly with acetaldehyde. Significant structural changes upon exposure were limited to surface phenomena, with the exception of the acetaldehyde-exposed sample.
- Full Text:
- Date Issued: 2019
Targeted attack detection by means of free and open source solutions
- Authors: Bernardo, Louis F
- Date: 2019
- Subjects: Computer networks -- Security measures , Information technology -- Security measures , Computer security -- Management , Data protection
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92269 , vital:30703
- Description: Compliance requirements are part of everyday business requirements for various areas, such as retail and medical services. As part of compliance it may be required to have infrastructure in place to monitor the activities in the environment to ensure that the relevant data and environment is sufficiently protected. At the core of such monitoring solutions one would find some type of data repository, or database, to store and ultimately correlate the captured events. Such solutions are commonly called Security Information and Event Management, or SIEM for short. Larger companies have been known to use commercial solutions such as IBM's Qradar, Logrythm, or Splunk. However, these come at significant cost and arent suitable for smaller businesses with limited budgets. These solutions require manual configuration of event correlation for detection of activities that place the environment in danger. This usually requires vendor implementation assistance that also would come at a cost. Alternatively, there are open source solutions that provide the required functionality. This research will demonstrate building an open source solution, with minimal to no cost for hardware or software, while still maintaining the capability of detecting targeted attacks. The solution presented in this research includes Wazuh, which is a combination of OSSEC and the ELK stack, integrated with an Network Intrusion Detection System (NIDS). The success of the integration, is determined by measuring postive attack detection based on each different configuration options. To perform the testing, a deliberately vulnerable platform named Metasploitable will be used as a victim host. The victim host vulnerabilities were created specifically to serve as target for Metasploit. The attacks were generated by utilising Metasploit Framework on a prebuilt Kali Linux host.
- Full Text:
- Date Issued: 2019
- Authors: Bernardo, Louis F
- Date: 2019
- Subjects: Computer networks -- Security measures , Information technology -- Security measures , Computer security -- Management , Data protection
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92269 , vital:30703
- Description: Compliance requirements are part of everyday business requirements for various areas, such as retail and medical services. As part of compliance it may be required to have infrastructure in place to monitor the activities in the environment to ensure that the relevant data and environment is sufficiently protected. At the core of such monitoring solutions one would find some type of data repository, or database, to store and ultimately correlate the captured events. Such solutions are commonly called Security Information and Event Management, or SIEM for short. Larger companies have been known to use commercial solutions such as IBM's Qradar, Logrythm, or Splunk. However, these come at significant cost and arent suitable for smaller businesses with limited budgets. These solutions require manual configuration of event correlation for detection of activities that place the environment in danger. This usually requires vendor implementation assistance that also would come at a cost. Alternatively, there are open source solutions that provide the required functionality. This research will demonstrate building an open source solution, with minimal to no cost for hardware or software, while still maintaining the capability of detecting targeted attacks. The solution presented in this research includes Wazuh, which is a combination of OSSEC and the ELK stack, integrated with an Network Intrusion Detection System (NIDS). The success of the integration, is determined by measuring postive attack detection based on each different configuration options. To perform the testing, a deliberately vulnerable platform named Metasploitable will be used as a victim host. The victim host vulnerabilities were created specifically to serve as target for Metasploit. The attacks were generated by utilising Metasploit Framework on a prebuilt Kali Linux host.
- Full Text:
- Date Issued: 2019
Targeting allosteric sites of Escherichia coli heat shock protein 70 for antibiotic development
- Authors: Okeke, Chiamaka Jessica
- Date: 2019
- Subjects: Heat shock proteins , Escherichia coli , Allosteric proteins , Antibiotics , Molecular chaperones , Ligands (Biochemistry) , Molecular dynamics , Principal components analysis , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/115998 , vital:34287
- Description: Hsp70s are members of the heat shock proteins family with a molecular weight of 70-kDa and are the most abundant group in bacterial and eukaryotic systems, hence the most extensively studied ones. These proteins are molecular chaperones that play a significant role in protein homeostasis by facilitating appropriate folding of proteins, preventing proteins from aggregating and misfolding. They are also involved in translocation of proteins into subcellular compartments and protection of cells against stress. Stress caused by environmental or biological factors affects the functionality of the cell. In response to these stressful conditions, up-regulation of Hsp70s ensures that the cells are protected by balancing out unfolded proteins giving them ample time to repair denatured proteins. Hsp70s is connected to numerous illnesses such as autoimmune and neurodegenerative diseases, bacterial infection, cancer, malaria, and obesity. The multi-functional nature of Hsp70s predisposes them as promising therapeutic targets. Hsp70s play vital roles in various cell developments, and survival pathways, therefore targeting this protein will provide a new avenue towards the discovery of active therapeutic agents for the treatment of a wide range of diseases. Allosteric sites of these proteins in its multi-conformational states have not been explored for inhibitory properties hence the aim of this study. This study aims at identifying allosteric sites that inhibit the ATPase and substrate binding activities using computational approaches. Using E. coli as a model organism, molecular docking for high throughput virtual screening was carried out using 623 compounds from the South African Natural Compounds Database (SANCDB; https://sancdb.rubi.ru.ac.za/) against identified allosteric sites. Ligands with the highest binding affinity (good binders) interacting with critical allosteric residues that are druggable were identified. Molecular dynamics (MD) simulation was also performed on the identified hits to assess for protein-inhibitor complex stability. Finally, principal component analysis (PCA) was performed to understand the structural dynamics of the ligand-free and ligand-bound structures during MD simulation.
- Full Text:
- Date Issued: 2019
- Authors: Okeke, Chiamaka Jessica
- Date: 2019
- Subjects: Heat shock proteins , Escherichia coli , Allosteric proteins , Antibiotics , Molecular chaperones , Ligands (Biochemistry) , Molecular dynamics , Principal components analysis , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/115998 , vital:34287
- Description: Hsp70s are members of the heat shock proteins family with a molecular weight of 70-kDa and are the most abundant group in bacterial and eukaryotic systems, hence the most extensively studied ones. These proteins are molecular chaperones that play a significant role in protein homeostasis by facilitating appropriate folding of proteins, preventing proteins from aggregating and misfolding. They are also involved in translocation of proteins into subcellular compartments and protection of cells against stress. Stress caused by environmental or biological factors affects the functionality of the cell. In response to these stressful conditions, up-regulation of Hsp70s ensures that the cells are protected by balancing out unfolded proteins giving them ample time to repair denatured proteins. Hsp70s is connected to numerous illnesses such as autoimmune and neurodegenerative diseases, bacterial infection, cancer, malaria, and obesity. The multi-functional nature of Hsp70s predisposes them as promising therapeutic targets. Hsp70s play vital roles in various cell developments, and survival pathways, therefore targeting this protein will provide a new avenue towards the discovery of active therapeutic agents for the treatment of a wide range of diseases. Allosteric sites of these proteins in its multi-conformational states have not been explored for inhibitory properties hence the aim of this study. This study aims at identifying allosteric sites that inhibit the ATPase and substrate binding activities using computational approaches. Using E. coli as a model organism, molecular docking for high throughput virtual screening was carried out using 623 compounds from the South African Natural Compounds Database (SANCDB; https://sancdb.rubi.ru.ac.za/) against identified allosteric sites. Ligands with the highest binding affinity (good binders) interacting with critical allosteric residues that are druggable were identified. Molecular dynamics (MD) simulation was also performed on the identified hits to assess for protein-inhibitor complex stability. Finally, principal component analysis (PCA) was performed to understand the structural dynamics of the ligand-free and ligand-bound structures during MD simulation.
- Full Text:
- Date Issued: 2019
Taxonomic and trait-based responses of the orders Ephemeroptera, Plecoptera, Odonata, And Trichoptera (EPOT) to sediment stress in the Tsitsa River and its tributaries, Eastern Cape, South Africa
- Akamagwuna, Frank Chukwuzuoke
- Authors: Akamagwuna, Frank Chukwuzuoke
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68082 , vital:29196
- Description: Increased urbanization and industrialisation due to human population growth and associated high demand for food have led to widespread disturbances of freshwater ecosystems and associated resources. A widely recognised consequence of these disturbances is the excessive delivery of sediments into the freshwater ecosystems, which severely affects the functioning and integrity of these systems.. The major water quality impairment in the Tsitsa River and its tributaries, situated in the Mzimvubu catchment in the Eastern Cape Province of South Africa, is known to be excessive sediment input. In this study, the application of macroinvertebrates taxonomic-based and trait-based approaches was used to assess the responses and vulnerability of Ephemeroptera, Plecoptera, Odonata and Trichoptera (EPOT) species to settled and suspended sediments stress in eight selected sampling sites in the Tsitsa River and its tributaries. The eight selected sites were Site 1 (Tsitsa upstream), Site 2 (Tsitsa downstream), Site 3 (Qurana tributary), Site 4 (Pot River upstream), Site 5 (Pot River downstream), Site 6 (Little Pot River), Site 7 (Millstream upstream) and Site 8 (Millstream downstream). The methods used in this study involved the analysis of water physico-chemical variables as well as sediment characteristics, derivation of five EPOT metrics, EPOT species-level taxonomic analysis, individual EPOT trait analysis and the development of a novel trait-based approach using a combination of traits. The sampling of EPOT taxa was done using the SASS5 protocols. Identification of EPOT was done to genus/species level and all data were subjected to relevant statistical analysis. The results of ecological categories derived for the physico-chemical variables generally indicated the ecological categories A and B, which was indicative of good water quality conditions. The result of sediment particle analysis revealed four distinct site groups: site group 1 (Tsitsa River upstream and Qurana tributary), site group 2 (Tsitsa River downstream and Millstream upstream), site group 3 (Pot River, both upstream and downstream, and Millstream downstream) and site group 4 (Little Pot River). The species-level taxonomic analysis of EPOT revealed that site group 1 was the most sediment-influenced sites whereas site group 4 was the least sediment-influenced. Species such as Paragopmhus sp., Aeshna sp. and Baetis sp. were considered sediment-tolerant with strong positive association with site group 1. The novel trait-based approach developed in this study proved useful in predicting the responses of EPOT species to sediment stress, and further discriminated between the study sites. The approach was used to group EPOT species into four vulnerability classes. The result showed that filter feeding EPOT species that have filamentous gills, preferring stone biotopes and feeding on detritus (FPOM) were mostly classified as highly vulnerable to sediment stress and indicated no significant association with the highly sediment-influenced site group 1. The TBA largely corresponded well to the predictions made with the relative abundance of the vulnerable class decreasing in the sediment-influenced sites compared to the tolerant and highly tolerant classes. Overall, the study revealed the importance of the complementary use of taxonomic and trait-based approaches to biomonitoring.
- Full Text:
- Date Issued: 2019
- Authors: Akamagwuna, Frank Chukwuzuoke
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68082 , vital:29196
- Description: Increased urbanization and industrialisation due to human population growth and associated high demand for food have led to widespread disturbances of freshwater ecosystems and associated resources. A widely recognised consequence of these disturbances is the excessive delivery of sediments into the freshwater ecosystems, which severely affects the functioning and integrity of these systems.. The major water quality impairment in the Tsitsa River and its tributaries, situated in the Mzimvubu catchment in the Eastern Cape Province of South Africa, is known to be excessive sediment input. In this study, the application of macroinvertebrates taxonomic-based and trait-based approaches was used to assess the responses and vulnerability of Ephemeroptera, Plecoptera, Odonata and Trichoptera (EPOT) species to settled and suspended sediments stress in eight selected sampling sites in the Tsitsa River and its tributaries. The eight selected sites were Site 1 (Tsitsa upstream), Site 2 (Tsitsa downstream), Site 3 (Qurana tributary), Site 4 (Pot River upstream), Site 5 (Pot River downstream), Site 6 (Little Pot River), Site 7 (Millstream upstream) and Site 8 (Millstream downstream). The methods used in this study involved the analysis of water physico-chemical variables as well as sediment characteristics, derivation of five EPOT metrics, EPOT species-level taxonomic analysis, individual EPOT trait analysis and the development of a novel trait-based approach using a combination of traits. The sampling of EPOT taxa was done using the SASS5 protocols. Identification of EPOT was done to genus/species level and all data were subjected to relevant statistical analysis. The results of ecological categories derived for the physico-chemical variables generally indicated the ecological categories A and B, which was indicative of good water quality conditions. The result of sediment particle analysis revealed four distinct site groups: site group 1 (Tsitsa River upstream and Qurana tributary), site group 2 (Tsitsa River downstream and Millstream upstream), site group 3 (Pot River, both upstream and downstream, and Millstream downstream) and site group 4 (Little Pot River). The species-level taxonomic analysis of EPOT revealed that site group 1 was the most sediment-influenced sites whereas site group 4 was the least sediment-influenced. Species such as Paragopmhus sp., Aeshna sp. and Baetis sp. were considered sediment-tolerant with strong positive association with site group 1. The novel trait-based approach developed in this study proved useful in predicting the responses of EPOT species to sediment stress, and further discriminated between the study sites. The approach was used to group EPOT species into four vulnerability classes. The result showed that filter feeding EPOT species that have filamentous gills, preferring stone biotopes and feeding on detritus (FPOM) were mostly classified as highly vulnerable to sediment stress and indicated no significant association with the highly sediment-influenced site group 1. The TBA largely corresponded well to the predictions made with the relative abundance of the vulnerable class decreasing in the sediment-influenced sites compared to the tolerant and highly tolerant classes. Overall, the study revealed the importance of the complementary use of taxonomic and trait-based approaches to biomonitoring.
- Full Text:
- Date Issued: 2019
Teachers’ engagement with learners in inclusive foundation phase classrooms: a case study analysis
- Authors: Skae, Vera Astrid
- Date: 2019
- Subjects: Early childhood education -- South Africa -- Eastern Cape -- Case studies , Education and state -- South Africa
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/92705 , vital:30722
- Description: Since 2001, South African teachers have been attempting to practise inclusive education in classrooms in ordinary, public schools. Previous research has shown the many challenges South African teachers face in our current educational environment. Strong arguments, however, have been made for more research to be done on actual teacher engagement with learners in our ordinary, public school classrooms, and the extent to which classroom practices are inclusive (Engelbrecht, Nel, Nel & Tlale, 2015, p. 3). This study sought to do an in-depth critical analysis of three foundation phase teachers and their engagement with learners in their classrooms at an Eastern Cape school. The aim was to examine how inclusive education was being enacted by the teacher with learners in real classroom settings, with particular attention paid to ways in which learners experience barriers to learning. A micro-level analysis was conducted in a single unit case study and using a qualitative research approach in an interpretive paradigm. Questionnaires, observations, and semi-structured interviews were conducted in an attempt to gather in-depth data. It was heartening to observe the extent to which inclusive education and practices were being enacted at the school and in the classrooms, and instructive in providing examples of what can work in the South African context. Key findings of this study include the generation of a framework for analysing inclusive classroom practice at the micro level. Criteria were identified as indicators of inclusive education of learners including those experiencing barriers to learning in the classroom. This study builds on and extends what has been developed at the macro and micro level of inclusive education in schools and in the classroom. It found that a number of challenges remain for enabling the implementation of an inclusive education. At the macro level, these include the provision of clear directives for implementation of inclusive education by the appropriate authorities; the provision of well-structured professional teacher training and development programmes in inclusive classroom practices, as well as in barriers to learning and how to address them; and the provision of funding for school and classroom infrastructure and resources. At the micro level, these include the successful implementation by teachers of inclusive classroom practices and the provision of the necessary support for learners experiencing barriers to learning in their classrooms, including expert personnel, resources, and assistive devices.
- Full Text:
- Date Issued: 2019
- Authors: Skae, Vera Astrid
- Date: 2019
- Subjects: Early childhood education -- South Africa -- Eastern Cape -- Case studies , Education and state -- South Africa
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/92705 , vital:30722
- Description: Since 2001, South African teachers have been attempting to practise inclusive education in classrooms in ordinary, public schools. Previous research has shown the many challenges South African teachers face in our current educational environment. Strong arguments, however, have been made for more research to be done on actual teacher engagement with learners in our ordinary, public school classrooms, and the extent to which classroom practices are inclusive (Engelbrecht, Nel, Nel & Tlale, 2015, p. 3). This study sought to do an in-depth critical analysis of three foundation phase teachers and their engagement with learners in their classrooms at an Eastern Cape school. The aim was to examine how inclusive education was being enacted by the teacher with learners in real classroom settings, with particular attention paid to ways in which learners experience barriers to learning. A micro-level analysis was conducted in a single unit case study and using a qualitative research approach in an interpretive paradigm. Questionnaires, observations, and semi-structured interviews were conducted in an attempt to gather in-depth data. It was heartening to observe the extent to which inclusive education and practices were being enacted at the school and in the classrooms, and instructive in providing examples of what can work in the South African context. Key findings of this study include the generation of a framework for analysing inclusive classroom practice at the micro level. Criteria were identified as indicators of inclusive education of learners including those experiencing barriers to learning in the classroom. This study builds on and extends what has been developed at the macro and micro level of inclusive education in schools and in the classroom. It found that a number of challenges remain for enabling the implementation of an inclusive education. At the macro level, these include the provision of clear directives for implementation of inclusive education by the appropriate authorities; the provision of well-structured professional teacher training and development programmes in inclusive classroom practices, as well as in barriers to learning and how to address them; and the provision of funding for school and classroom infrastructure and resources. At the micro level, these include the successful implementation by teachers of inclusive classroom practices and the provision of the necessary support for learners experiencing barriers to learning in their classrooms, including expert personnel, resources, and assistive devices.
- Full Text:
- Date Issued: 2019
Template ecological analsyis of the narratives of partner’s and family member’s of women who consumed alcohol in pregnancy
- Authors: Tsetse, Agrinette Nontozamo
- Date: 2019
- Subjects: Pregnant women -- Alcohol use -- Social aspects , Substance abuse in pregnancy , Fetus -- Effect of drugs on , Pregnancy -- Psychological aspects , Pregnant women -- Substance use , Substance abuse -- Social aspects , Ecological Systems Theory
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/114905 , vital:34055
- Description: Although there is increasing research on alcohol in South Africa, most of this work has an epidemiological focus. Very little research has explored alcohol use during pregnancy specifically from the perspective of the woman’s partner or family member or focused on contextual risk factors beyond the pregnant woman. This information is important to ensure that interventions are formulated based on the social contexts within which drinking in pregnancy takes place and in guiding interventions that aim to prevent prenatal alcohol use, thereby preventing the occurrence of FASDs. This study was guided by Bronfenbrenner’s Ecological Systems Theory to understand partners’ and family members’ perspectives of prenatal exposure within the actual environments in which alcohol use takes place. According to this theory, an individual exists within layers of social relationships: the family, intimate partners, friendships, and healthcare workers (microsystems), interactions among these microsystems, for example, interaction between healthcare workers and intimate partner and family and social workers (mesosystem), accessibility of alcohol in the neighbourhoods (exosystems), religion, culture and society (macro-systems) and changes of the individual and socio-historical context (chronosystem). The data were collected using a biographic narrative interpretive method of interviewing. Thirteen narratives interviews were conducted with partners and family members in a disadvantaged community in Buffalo City, Eastern Cape Province. The interviews were analysed using Template Analysis within the Ecological Systems Theory to interrogate the stories of partners and family members. According to participants, some of the reasons women consumed alcohol in pregnancy are: drinking habits before pregnancy that were difficult to break in pregnancy; women drank during the first trimester of their pregnancy because of unplanned pregnancy; women continued drinking throughout their pregnancies to cope with the emotional upset caused by the trauma of rape and losing loved ones, stress, receiving HIV-diagnosis in pregnancy, intimate partner violence, infidelity, rejection and denial of pregnancy from partners. After birth, some women continued drinking. Consequently, their children were taken away from them by social workers and family members because the parents were unable to care for the child due to alcohol use. There was lack of compliance of shebeens with liquor regulations, heavy drinking, high rates of alcohol use in pregnancy, and easy accessibility of alcohol within this study community. Pregnant women used religious coping beliefs to cope with their circumstances such as changes in their health, relationships and finances. Drinking during pregnancy is a complex problem that stems from multiple social and structural issues and interventions should therefore not only focus on the individual, but also on social networks and communities.
- Full Text:
- Date Issued: 2019
- Authors: Tsetse, Agrinette Nontozamo
- Date: 2019
- Subjects: Pregnant women -- Alcohol use -- Social aspects , Substance abuse in pregnancy , Fetus -- Effect of drugs on , Pregnancy -- Psychological aspects , Pregnant women -- Substance use , Substance abuse -- Social aspects , Ecological Systems Theory
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/114905 , vital:34055
- Description: Although there is increasing research on alcohol in South Africa, most of this work has an epidemiological focus. Very little research has explored alcohol use during pregnancy specifically from the perspective of the woman’s partner or family member or focused on contextual risk factors beyond the pregnant woman. This information is important to ensure that interventions are formulated based on the social contexts within which drinking in pregnancy takes place and in guiding interventions that aim to prevent prenatal alcohol use, thereby preventing the occurrence of FASDs. This study was guided by Bronfenbrenner’s Ecological Systems Theory to understand partners’ and family members’ perspectives of prenatal exposure within the actual environments in which alcohol use takes place. According to this theory, an individual exists within layers of social relationships: the family, intimate partners, friendships, and healthcare workers (microsystems), interactions among these microsystems, for example, interaction between healthcare workers and intimate partner and family and social workers (mesosystem), accessibility of alcohol in the neighbourhoods (exosystems), religion, culture and society (macro-systems) and changes of the individual and socio-historical context (chronosystem). The data were collected using a biographic narrative interpretive method of interviewing. Thirteen narratives interviews were conducted with partners and family members in a disadvantaged community in Buffalo City, Eastern Cape Province. The interviews were analysed using Template Analysis within the Ecological Systems Theory to interrogate the stories of partners and family members. According to participants, some of the reasons women consumed alcohol in pregnancy are: drinking habits before pregnancy that were difficult to break in pregnancy; women drank during the first trimester of their pregnancy because of unplanned pregnancy; women continued drinking throughout their pregnancies to cope with the emotional upset caused by the trauma of rape and losing loved ones, stress, receiving HIV-diagnosis in pregnancy, intimate partner violence, infidelity, rejection and denial of pregnancy from partners. After birth, some women continued drinking. Consequently, their children were taken away from them by social workers and family members because the parents were unable to care for the child due to alcohol use. There was lack of compliance of shebeens with liquor regulations, heavy drinking, high rates of alcohol use in pregnancy, and easy accessibility of alcohol within this study community. Pregnant women used religious coping beliefs to cope with their circumstances such as changes in their health, relationships and finances. Drinking during pregnancy is a complex problem that stems from multiple social and structural issues and interventions should therefore not only focus on the individual, but also on social networks and communities.
- Full Text:
- Date Issued: 2019
The Afropolitan flâneur: literary representations of the city and contemporary urban identities in selected African and transnational texts
- Authors: Leff, Carol Willa
- Date: 2019
- Subjects: City and town life in literature , African literature (English) -- History and criticism , Flaneurs in literature
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115082 , vital:34076
- Description: When an individual walks the urban landscape there is a unique symbiosis between self and city. It is through walking the cityscape and observing the crowd and the surrounding environment that the archetypal literary figure of the European flâneur acts as a mirror of a particular time and space. But how might such a flâneur walk and observe the city in contemporary African and transnational literary texts? I argue that there is a literary re-imagining and repurposing of the flâneur figure which has hitherto not been acknowledged and explored: an Afropolitan flâneur. ‘Afropolitan’ is a term popularised by Taiye Selasi in a 2005 essay to refer to a ‘scattered tribe’ of ‘Africans of the world’ (n. pag.). In this dissertation, the entanglement of the Afropolitan subject and the European flâneur brings together past and present, Africa and the West. I first provide a historical and theoretical framework to illustrate how the flâneur figure ‘migrated’ from Europe to Africa, and how this figure is to be understood as a literary construct, in relation to current considerations of Afropolitanism. I go on to discuss a wide range of texts that engage with Afropolitan flâneurs who traverse cities in Africa (such as Johannesburg, Cape Town and Lagos), or global north cities (New York, Paris and London). While some of the Afropolitan flâneurs depicted in these texts are migrants or homeless individuals who struggle to adapt easily to a new environment, others, despite being more privileged, also sometimes experience uncomfortable assimilation in their new or strange city space. There are also those who seem to feel equally at home wherever they find themselves. As these Afropolitan flâneurs walk their way through the urban landscape in the texts under examination, they reflect different ways of being in the city. By problematising the binaries of local/global, national/transnational, black/white, slum/paradise, this dissertation seeks to address issues of belonging or not belonging and gestures towards new ways of understanding what it means to be an African in the world.
- Full Text:
- Date Issued: 2019
- Authors: Leff, Carol Willa
- Date: 2019
- Subjects: City and town life in literature , African literature (English) -- History and criticism , Flaneurs in literature
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115082 , vital:34076
- Description: When an individual walks the urban landscape there is a unique symbiosis between self and city. It is through walking the cityscape and observing the crowd and the surrounding environment that the archetypal literary figure of the European flâneur acts as a mirror of a particular time and space. But how might such a flâneur walk and observe the city in contemporary African and transnational literary texts? I argue that there is a literary re-imagining and repurposing of the flâneur figure which has hitherto not been acknowledged and explored: an Afropolitan flâneur. ‘Afropolitan’ is a term popularised by Taiye Selasi in a 2005 essay to refer to a ‘scattered tribe’ of ‘Africans of the world’ (n. pag.). In this dissertation, the entanglement of the Afropolitan subject and the European flâneur brings together past and present, Africa and the West. I first provide a historical and theoretical framework to illustrate how the flâneur figure ‘migrated’ from Europe to Africa, and how this figure is to be understood as a literary construct, in relation to current considerations of Afropolitanism. I go on to discuss a wide range of texts that engage with Afropolitan flâneurs who traverse cities in Africa (such as Johannesburg, Cape Town and Lagos), or global north cities (New York, Paris and London). While some of the Afropolitan flâneurs depicted in these texts are migrants or homeless individuals who struggle to adapt easily to a new environment, others, despite being more privileged, also sometimes experience uncomfortable assimilation in their new or strange city space. There are also those who seem to feel equally at home wherever they find themselves. As these Afropolitan flâneurs walk their way through the urban landscape in the texts under examination, they reflect different ways of being in the city. By problematising the binaries of local/global, national/transnational, black/white, slum/paradise, this dissertation seeks to address issues of belonging or not belonging and gestures towards new ways of understanding what it means to be an African in the world.
- Full Text:
- Date Issued: 2019
The Chase: historical and ethnographic observations on ‘Traditional Horse Racing’ in the Eastern Cape, c. 1850 to the present
- Authors: Paterson, Craig John
- Date: 2019
- Subjects: Horse racing -- South Africa -- Homelands , Masculinity -- South Africa – Homelands -- History , Migrant labor -- South Africa , Masculinity in sports -- South Africa -- Homelands Group identity -- South Africa – Homelands -- History , South Africa -- Social conditions -- 1961-1994 , South Africa -- Politics and government -- 20th century
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115328 , vital:34114
- Description: This thesis examines the development of a horse racing sport, umdyarho wamahashe, as it is practised in the former-bantustans of the Eastern Cape Province. Using varied source material – ethnographic, archival and oral – it provides a guide to understanding the historical development of umdyarho events and their meaning to participants. By drawing together available ‘fragments’ of material on horses and horse racing in the former-bantustans of Transkei and Ciskei, it argues that horse racing is derived from a pre-colonial cattle racing tradition which was made impossible by a collision of environmental pressures and colonial responses to them. It goes on to show how horses came to take on a ‘symbol set’ of masculine power and “growing up.” The nexus of horses, rapidly assimilated into daily life, and the changing material conditions confronting the people of the Eastern Cape, made horse racing an ideal outlet through which men might regain a sense of power in conditions which eroded their sense of control over their daily lives, and, as a result, their perceived masculinity. This thesis argues that through horse races, people of the Eastern Cape were provided an space in which they could at once celebrate their legacy (by acting as their ‘forebears’ did) and their potential (by showing who they would like to be, through the deployment of the horse as a symbol). It concludes by discussing and how the imposition of change from outside threatens the ‘spirit’ of this sport.
- Full Text:
- Date Issued: 2019
- Authors: Paterson, Craig John
- Date: 2019
- Subjects: Horse racing -- South Africa -- Homelands , Masculinity -- South Africa – Homelands -- History , Migrant labor -- South Africa , Masculinity in sports -- South Africa -- Homelands Group identity -- South Africa – Homelands -- History , South Africa -- Social conditions -- 1961-1994 , South Africa -- Politics and government -- 20th century
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115328 , vital:34114
- Description: This thesis examines the development of a horse racing sport, umdyarho wamahashe, as it is practised in the former-bantustans of the Eastern Cape Province. Using varied source material – ethnographic, archival and oral – it provides a guide to understanding the historical development of umdyarho events and their meaning to participants. By drawing together available ‘fragments’ of material on horses and horse racing in the former-bantustans of Transkei and Ciskei, it argues that horse racing is derived from a pre-colonial cattle racing tradition which was made impossible by a collision of environmental pressures and colonial responses to them. It goes on to show how horses came to take on a ‘symbol set’ of masculine power and “growing up.” The nexus of horses, rapidly assimilated into daily life, and the changing material conditions confronting the people of the Eastern Cape, made horse racing an ideal outlet through which men might regain a sense of power in conditions which eroded their sense of control over their daily lives, and, as a result, their perceived masculinity. This thesis argues that through horse races, people of the Eastern Cape were provided an space in which they could at once celebrate their legacy (by acting as their ‘forebears’ did) and their potential (by showing who they would like to be, through the deployment of the horse as a symbol). It concludes by discussing and how the imposition of change from outside threatens the ‘spirit’ of this sport.
- Full Text:
- Date Issued: 2019
The conservation, ecology, and distribution of the critically endangered Encephalartos latifrons Lehm
- Authors: Swart, Carin
- Date: 2019
- Subjects: Encephalartos , Cycadaceae , Cycads -- Conservation -- South Africa , Botany, Economic -- South Africa , Rare plants -- South Africa , Endangered plants -- South Africa , Wild plant trade -- Law and legislation -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/94483 , vital:31049
- Description: Cycads have attracted global attention both as horticulturally interesting and often valuable plants; but also as some of the most threatened organisms on the planet. In this thesis I investigate the conservation management, biology, reproductive ecology and distribution of Encephalartos latifrons populations in the wild and draw out conclusions on how best to conserve global cycad biodiversity. I also employ computer-modelling techniques in some of the chapters of this thesis to demonstrate how to improve conservation outcomes for E. latifrons and endangered species in general, where information on the distribution, biology and habitat requirements of such species are inherently limited, often precluding robust conservation decision-making. In Chapter 1 of this thesis I introduce the concept of extinction debt and elucidate the importance of in situ cycad conservation. I explain how the concept of extinction debt relates to single species, as well as give details on the mechanisms causing extinction debt in cycad populations. I introduce the six extinction trajectory threshold model and how this relates to extinction debt in cycads. I discuss the vulnerability of cycads to extinction and give an overview of biodiversity policy in South Africa. I expand on how national and global policies contribute to cycad conservation and present various global initiatives that support threatened species conservation. I conclude Chapter 1 by explaining how computer-based models can assist conservation decision-making for rare, threatened, and endangered species in the face of uncertainty. Chapter 2 of this thesis illustrates how a modelling approach, using limited available historical and present day locality information, is a feasible method to determine areas of suitable habitat for E. latifrons and other critically endangered cycad species where locality information is inherently uncommon. Results from this chapter show that conservation planning through structured decision-making may be improved by the use of computer models, even when locality data are limited. These results may be incorporated into biodiversity conservation plans or used to assist conservation-decision makers when undertaking recovery efforts for E. latifrons and may provide guidance to conservation planners and policy makers when undertaking conservation plans to improve cycad biodiversity both nationally and globally. There was limited information available in the biology and ecological requirements of E. latifrons. This information is important when making policy decisions such as the publication of non-detriment findings and compiling biodiversity management plans for this and other cycad species. Chapter 3 investigates the life-history, population structure, fire response and survival of an in situ E. latifrons population. A demographic census was undertaken between 2013 and 2017 on a previously undiscovered population. Population characteristics of the “new” population were compared to the demographics of a well-known and intensively managed population. Results of this chapter show that at least one in situ E. latifrons population is stable and increasing under current environmental conditions. Importantly, the population is naturally recruiting seedlings without the need for artificial pollination. Demographic information described in this chapter is a necessary precursor to undertaking a Population Viability Assessment for the species. This will assist conservation decision-makers when determining the best conservation management strategy for E. latifrons. It may also be useful to apply generalisatons to other cycad species (with similar life-histories and habitat requirements) where there is limited information available on the species biological and ecological requirements, restricting robust policy conservation decision-making. It was important for this study to determine the extent and variety of cone fauna within existing E. latifrons wild populations. Previous anecdotal evidence suggested that E. latifrons is functionally extinct as a species, but evidence to the contrary was found when a healthy, self-sustaining wild population was discovered to be naturally recruiting. It was important to establish the existence and diversity of male cone faunal species (an important breeding site for weevil pollinators) within wild populations. Chapter 4 set out to determine if potential pollinators exist in the wild and if so, how diverse are they and in what numbers. This is the first comprehensive analysis of cone fauna present in wild E. latifrons populations. Equally important was the need to determine if wild populations are capable of producing viable seeds under conditions conducive to natural pollination. Results of this chapter show that there is a relatively high diversity of insect fauna in the male cones of some wild E. latifrons populations. Furthermore, some wild populations are capable of producing viable seeds through natural pollination; even though they may not be naturally recruiting seedlings into the population. A staggered germination pattern displayed by one of the wild E. latifrons populations was studied, suggesting the evolution of an adaptive trait given the stochastic environment (climatically and disturbances such as fire) within which E. latifrons populations may be found. Species recovery (restoration and/or population augmentation) may be the only conservation solution remaining to save endangered species such as E. latifrons from extinction in the wild. Chapter 5 involves the return of 25 seedlings germinated as part of a seed viability experiment (see Chapter 4) back into a wild population from where they originated. The primary threat to seedling survival at the site was livestock activity (grazing/trampling). The population was subsequently fenced off to mitigate this threat and seedlings planted both inside and outside a fenced area to establish if there was a difference in seedling survival between the unprotected and protected sites. A high percentage (92%) of seedlings planted perished in total. None of the seedlings planted outside the fenced area survived over the monitoring period, while only two seedlings planted within the fenced area survived. Survival of the seedlings inside the fenced area was only after placing individual cages on the seedlings to prevent further losses. The primary causes of death for all seedlings included uprooting, and defoliation with some of the seedlings missing completely. This chapter found that the lack of natural seedling recruitment at the site was as a result of livestock activity. Grazing by livestock poses a significant threat to natural recruitment in some E. latifrons populations. Alternative restoration methods are suggested and protection of seedlings while undertaking a restoration/augmentation programme is emphasised. Developing conservation management plans for rare and/or endangered species is often met with high levels of uncertainty, particularly if there is limited information available on the biology and ecological requirements for the species concerned. Population viability analysis (PVA) is often suggested as a tool to determine conservation management scenarios that may enhance wild population persistence. The standard PVA approach is however problematic as it is a time-consuming process requiring the collection of demographic data over long time periods. In addition, the PVA approach does not take in to account non-biological factors which may impede the effective implementation of conservation plans. Chapter 6 of this thesis makes use of a Multi-Criteria Decision Making (MCDM) approach called the Analytical Hierarchy Process (AHP) to decide on the best conservation management strategy for an E. latifrons population. Sensitivity analysis was completed to test the robustness of the decision and to identify which criteria influenced the original results. In this study, the development of the decision tree and criteria judgements, were made solely by the researcher. It is emphasised that the decision outcome may be biased if not conducted as part of a multi-stakeholder workshop using the same approach. Nevertheless, it is recommended that a Population Viability Risk Management (PVRM) assessment be undertaken for E. latifrons using an MCDM approach such as AHP as a prestudy, before the revision of the Biodiversity Management Plan (BMP) for E. latifrons. This method is particularly useful when non-biological criteria are to be incorporated into the decision-making process. It is also a viable and holistic alternative to the standard PVA approach when developing conservation management plans for rare and endangered species. In Chapter 7 I review the concept of extinction debt in cycads using E. latifrons as an example. I assimilate historical information to understand mechanisms that may have impacted on E. latifrons populations in the past. This was done to understand the scale of extinction time lags on E. latifrons and to relate this to its present position on the exitinction trajectory. I recommend aligning South African policies and biodiversity assessments with international initiatives and draw out general conclusions for the conservation of global cycad biodiversity. I conclude by recommending further research for E. latifrons.
- Full Text:
- Date Issued: 2019
- Authors: Swart, Carin
- Date: 2019
- Subjects: Encephalartos , Cycadaceae , Cycads -- Conservation -- South Africa , Botany, Economic -- South Africa , Rare plants -- South Africa , Endangered plants -- South Africa , Wild plant trade -- Law and legislation -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/94483 , vital:31049
- Description: Cycads have attracted global attention both as horticulturally interesting and often valuable plants; but also as some of the most threatened organisms on the planet. In this thesis I investigate the conservation management, biology, reproductive ecology and distribution of Encephalartos latifrons populations in the wild and draw out conclusions on how best to conserve global cycad biodiversity. I also employ computer-modelling techniques in some of the chapters of this thesis to demonstrate how to improve conservation outcomes for E. latifrons and endangered species in general, where information on the distribution, biology and habitat requirements of such species are inherently limited, often precluding robust conservation decision-making. In Chapter 1 of this thesis I introduce the concept of extinction debt and elucidate the importance of in situ cycad conservation. I explain how the concept of extinction debt relates to single species, as well as give details on the mechanisms causing extinction debt in cycad populations. I introduce the six extinction trajectory threshold model and how this relates to extinction debt in cycads. I discuss the vulnerability of cycads to extinction and give an overview of biodiversity policy in South Africa. I expand on how national and global policies contribute to cycad conservation and present various global initiatives that support threatened species conservation. I conclude Chapter 1 by explaining how computer-based models can assist conservation decision-making for rare, threatened, and endangered species in the face of uncertainty. Chapter 2 of this thesis illustrates how a modelling approach, using limited available historical and present day locality information, is a feasible method to determine areas of suitable habitat for E. latifrons and other critically endangered cycad species where locality information is inherently uncommon. Results from this chapter show that conservation planning through structured decision-making may be improved by the use of computer models, even when locality data are limited. These results may be incorporated into biodiversity conservation plans or used to assist conservation-decision makers when undertaking recovery efforts for E. latifrons and may provide guidance to conservation planners and policy makers when undertaking conservation plans to improve cycad biodiversity both nationally and globally. There was limited information available in the biology and ecological requirements of E. latifrons. This information is important when making policy decisions such as the publication of non-detriment findings and compiling biodiversity management plans for this and other cycad species. Chapter 3 investigates the life-history, population structure, fire response and survival of an in situ E. latifrons population. A demographic census was undertaken between 2013 and 2017 on a previously undiscovered population. Population characteristics of the “new” population were compared to the demographics of a well-known and intensively managed population. Results of this chapter show that at least one in situ E. latifrons population is stable and increasing under current environmental conditions. Importantly, the population is naturally recruiting seedlings without the need for artificial pollination. Demographic information described in this chapter is a necessary precursor to undertaking a Population Viability Assessment for the species. This will assist conservation decision-makers when determining the best conservation management strategy for E. latifrons. It may also be useful to apply generalisatons to other cycad species (with similar life-histories and habitat requirements) where there is limited information available on the species biological and ecological requirements, restricting robust policy conservation decision-making. It was important for this study to determine the extent and variety of cone fauna within existing E. latifrons wild populations. Previous anecdotal evidence suggested that E. latifrons is functionally extinct as a species, but evidence to the contrary was found when a healthy, self-sustaining wild population was discovered to be naturally recruiting. It was important to establish the existence and diversity of male cone faunal species (an important breeding site for weevil pollinators) within wild populations. Chapter 4 set out to determine if potential pollinators exist in the wild and if so, how diverse are they and in what numbers. This is the first comprehensive analysis of cone fauna present in wild E. latifrons populations. Equally important was the need to determine if wild populations are capable of producing viable seeds under conditions conducive to natural pollination. Results of this chapter show that there is a relatively high diversity of insect fauna in the male cones of some wild E. latifrons populations. Furthermore, some wild populations are capable of producing viable seeds through natural pollination; even though they may not be naturally recruiting seedlings into the population. A staggered germination pattern displayed by one of the wild E. latifrons populations was studied, suggesting the evolution of an adaptive trait given the stochastic environment (climatically and disturbances such as fire) within which E. latifrons populations may be found. Species recovery (restoration and/or population augmentation) may be the only conservation solution remaining to save endangered species such as E. latifrons from extinction in the wild. Chapter 5 involves the return of 25 seedlings germinated as part of a seed viability experiment (see Chapter 4) back into a wild population from where they originated. The primary threat to seedling survival at the site was livestock activity (grazing/trampling). The population was subsequently fenced off to mitigate this threat and seedlings planted both inside and outside a fenced area to establish if there was a difference in seedling survival between the unprotected and protected sites. A high percentage (92%) of seedlings planted perished in total. None of the seedlings planted outside the fenced area survived over the monitoring period, while only two seedlings planted within the fenced area survived. Survival of the seedlings inside the fenced area was only after placing individual cages on the seedlings to prevent further losses. The primary causes of death for all seedlings included uprooting, and defoliation with some of the seedlings missing completely. This chapter found that the lack of natural seedling recruitment at the site was as a result of livestock activity. Grazing by livestock poses a significant threat to natural recruitment in some E. latifrons populations. Alternative restoration methods are suggested and protection of seedlings while undertaking a restoration/augmentation programme is emphasised. Developing conservation management plans for rare and/or endangered species is often met with high levels of uncertainty, particularly if there is limited information available on the biology and ecological requirements for the species concerned. Population viability analysis (PVA) is often suggested as a tool to determine conservation management scenarios that may enhance wild population persistence. The standard PVA approach is however problematic as it is a time-consuming process requiring the collection of demographic data over long time periods. In addition, the PVA approach does not take in to account non-biological factors which may impede the effective implementation of conservation plans. Chapter 6 of this thesis makes use of a Multi-Criteria Decision Making (MCDM) approach called the Analytical Hierarchy Process (AHP) to decide on the best conservation management strategy for an E. latifrons population. Sensitivity analysis was completed to test the robustness of the decision and to identify which criteria influenced the original results. In this study, the development of the decision tree and criteria judgements, were made solely by the researcher. It is emphasised that the decision outcome may be biased if not conducted as part of a multi-stakeholder workshop using the same approach. Nevertheless, it is recommended that a Population Viability Risk Management (PVRM) assessment be undertaken for E. latifrons using an MCDM approach such as AHP as a prestudy, before the revision of the Biodiversity Management Plan (BMP) for E. latifrons. This method is particularly useful when non-biological criteria are to be incorporated into the decision-making process. It is also a viable and holistic alternative to the standard PVA approach when developing conservation management plans for rare and endangered species. In Chapter 7 I review the concept of extinction debt in cycads using E. latifrons as an example. I assimilate historical information to understand mechanisms that may have impacted on E. latifrons populations in the past. This was done to understand the scale of extinction time lags on E. latifrons and to relate this to its present position on the exitinction trajectory. I recommend aligning South African policies and biodiversity assessments with international initiatives and draw out general conclusions for the conservation of global cycad biodiversity. I conclude by recommending further research for E. latifrons.
- Full Text:
- Date Issued: 2019
The development of a larval feeding regimen for dusky kob, Argyrosomus japonicus, with a specific focus on the effect of weaning period on larval development and survival
- Authors: Keet, Thomas
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/96897 , vital:31344
- Description: One of the biggest limiting factors in marine finfish aquaculture is the low survival rate of early-stage larvae. Most mortalities can be ascribed to the poor nutritional value of live feeds, sibling cannibalism, and various stressors that result in swim bladder hyperinflation and/or starvation during the larval stage. Research results vary on the best timing for the introduction of artificial feed for good survival and growth rate in dusky kob larvae. The main objective of this experiment was to improve survival and growth rate. The experiment focused on a new feeding regime that sought to wean larvae onto an artificial diet earlier than the current Argyrosomus japonicus standard (weaning commenced at 16 days after hatch (DAH) versus 20 days after hatch), based on findings and recommendations made by Musson & Kaiser (2014). Three trials were conducted, each with five replicates of the two treatments, namely the new feeding regime and the standard feeding regime in a fully randomised design. Samples from each tank were collected every two days for the duration of the trial. Morphometric measurements (standard length; body depth; eye diameter) obtained from these sample larvae were used to compare growth rates between treatments. The ratio of BD:SL was used to assess larval condition throughout each trial. Tank survival rates were calculated on the last day of each trial.The study indicated that in mean water temperatures ranging from 24.3 – 25.2 °C, dusky kob larvae can be weaned onto an artificial pellet diet from 16 - 21 DAH without any negative effects on growth, condition and survival. Results from the highest mean temperatures of Trial 2 show a better mean condition in the treatment group during the weaning period (p < 0.05). In Trial 3, with its lower mean water temperatures of 23.2 °C, larvae in both treatments showed stunted absolute growth rates of all biometrics when compared to results from the higher mean temperatures of Trials 1 and 2. During the first 6 days of Trial 3 larvae were in relatively poor condition, BD:SL ≤ 0.30. During this same period in Trials 1 and 2, mean BD:SL ≥ 0.31, suggesting that a BD:SL ratio of ≤ 0.30 in non-weaned dusky kob larvae is an indicator of a degree of starvation. A future study on the morphology and histology of the larval gastrointestinal tract, specifically the liver and intestines, and how this early weaning regime affects their ontogeny under differing temperature conditions this needed to investigate the validity of these initial data on dusky kob larvae condition.
- Full Text:
- Date Issued: 2019
- Authors: Keet, Thomas
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/96897 , vital:31344
- Description: One of the biggest limiting factors in marine finfish aquaculture is the low survival rate of early-stage larvae. Most mortalities can be ascribed to the poor nutritional value of live feeds, sibling cannibalism, and various stressors that result in swim bladder hyperinflation and/or starvation during the larval stage. Research results vary on the best timing for the introduction of artificial feed for good survival and growth rate in dusky kob larvae. The main objective of this experiment was to improve survival and growth rate. The experiment focused on a new feeding regime that sought to wean larvae onto an artificial diet earlier than the current Argyrosomus japonicus standard (weaning commenced at 16 days after hatch (DAH) versus 20 days after hatch), based on findings and recommendations made by Musson & Kaiser (2014). Three trials were conducted, each with five replicates of the two treatments, namely the new feeding regime and the standard feeding regime in a fully randomised design. Samples from each tank were collected every two days for the duration of the trial. Morphometric measurements (standard length; body depth; eye diameter) obtained from these sample larvae were used to compare growth rates between treatments. The ratio of BD:SL was used to assess larval condition throughout each trial. Tank survival rates were calculated on the last day of each trial.The study indicated that in mean water temperatures ranging from 24.3 – 25.2 °C, dusky kob larvae can be weaned onto an artificial pellet diet from 16 - 21 DAH without any negative effects on growth, condition and survival. Results from the highest mean temperatures of Trial 2 show a better mean condition in the treatment group during the weaning period (p < 0.05). In Trial 3, with its lower mean water temperatures of 23.2 °C, larvae in both treatments showed stunted absolute growth rates of all biometrics when compared to results from the higher mean temperatures of Trials 1 and 2. During the first 6 days of Trial 3 larvae were in relatively poor condition, BD:SL ≤ 0.30. During this same period in Trials 1 and 2, mean BD:SL ≥ 0.31, suggesting that a BD:SL ratio of ≤ 0.30 in non-weaned dusky kob larvae is an indicator of a degree of starvation. A future study on the morphology and histology of the larval gastrointestinal tract, specifically the liver and intestines, and how this early weaning regime affects their ontogeny under differing temperature conditions this needed to investigate the validity of these initial data on dusky kob larvae condition.
- Full Text:
- Date Issued: 2019
The development of a larval feeding regimen for dusky kob, Argyrosomus japonicus, with a specific focus on the effect of weaning period on larval development and survival
- Authors: Keet, Thomas
- Date: 2019
- Subjects: Argyrosomus japonicus , Argyrosomus , Argyrosomus japonicus -- Larvae , Argyrosomus -- Larvae , Argyrosomus japonicus -- Larvae -- Nutrition , Argyrosomus -- Larvae -- Nutrition
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146577 , vital:38538
- Description: One of the biggest limiting factors in marine finfish aquaculture is the low survival rate of early-stage larvae. Most mortalities can be ascribed to the poor nutritional value of live feeds, sibling cannibalism, and various stressors that result in swim bladder hyperinflation and/or starvation during the larval stage. Research results vary on the best timing for the introduction of artificial feed for good survival and growth rate in dusky kob larvae. The main objective of this experiment was to improve survival and growth rate. The experiment focused on a new feeding regime that sought to wean larvae onto an artificial diet earlier than the current Argyrosomus japonicus standard (weaning commenced at 16 days after hatch (DAH) versus 20 days after hatch), based on findings and recommendations made by Musson & Kaiser (2014). Three trials were conducted, each with five replicates of the two treatments, namely the new feeding regime and the standard feeding regime in a fully randomised design. Samples from each tank were collected every two days for the duration of the trial. Morphometric measurements (standard length; body depth; eye diameter) obtained from these sample larvae were used to compare growth rates between treatments. The ratio of BD:SL was used to assess larval condition throughout each trial. Tank survival rates were calculated on the last day of each trial.The study indicated that in mean water temperatures ranging from 24.3 – 25.2 °C, dusky kob larvae can be weaned onto an artificial pellet diet from 16 - 21 DAH without any negative effects on growth, condition and survival. Results from the highest mean temperatures of Trial 2 show a better mean condition in the treatment group during the weaning period (p < 0.05). In Trial 3, with its lower mean water temperatures of 23.2 °C, larvae in both treatments showed stunted absolute growth rates of all biometrics when compared to results from the higher mean temperatures of Trials 1 and 2. During the first 6 days of Trial 3 larvae were in relatively poor condition, BD:SL ≤ 0.30. During this same period in Trials 1 and 2, mean BD:SL ≥ 0.31, suggesting that a BD:SL ratio of ≤ 0.30 in non-weaned dusky kob larvae is an indicator of a degree of starvation. A future study on the morphology and histology of the larval gastrointestinal tract, specifically the liver and intestines, and how this early weaning regime affects their ontogeny under differing temperature conditions this needed to investigate the validity of these initial data on dusky kob larvae condition.
- Full Text:
- Date Issued: 2019
- Authors: Keet, Thomas
- Date: 2019
- Subjects: Argyrosomus japonicus , Argyrosomus , Argyrosomus japonicus -- Larvae , Argyrosomus -- Larvae , Argyrosomus japonicus -- Larvae -- Nutrition , Argyrosomus -- Larvae -- Nutrition
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146577 , vital:38538
- Description: One of the biggest limiting factors in marine finfish aquaculture is the low survival rate of early-stage larvae. Most mortalities can be ascribed to the poor nutritional value of live feeds, sibling cannibalism, and various stressors that result in swim bladder hyperinflation and/or starvation during the larval stage. Research results vary on the best timing for the introduction of artificial feed for good survival and growth rate in dusky kob larvae. The main objective of this experiment was to improve survival and growth rate. The experiment focused on a new feeding regime that sought to wean larvae onto an artificial diet earlier than the current Argyrosomus japonicus standard (weaning commenced at 16 days after hatch (DAH) versus 20 days after hatch), based on findings and recommendations made by Musson & Kaiser (2014). Three trials were conducted, each with five replicates of the two treatments, namely the new feeding regime and the standard feeding regime in a fully randomised design. Samples from each tank were collected every two days for the duration of the trial. Morphometric measurements (standard length; body depth; eye diameter) obtained from these sample larvae were used to compare growth rates between treatments. The ratio of BD:SL was used to assess larval condition throughout each trial. Tank survival rates were calculated on the last day of each trial.The study indicated that in mean water temperatures ranging from 24.3 – 25.2 °C, dusky kob larvae can be weaned onto an artificial pellet diet from 16 - 21 DAH without any negative effects on growth, condition and survival. Results from the highest mean temperatures of Trial 2 show a better mean condition in the treatment group during the weaning period (p < 0.05). In Trial 3, with its lower mean water temperatures of 23.2 °C, larvae in both treatments showed stunted absolute growth rates of all biometrics when compared to results from the higher mean temperatures of Trials 1 and 2. During the first 6 days of Trial 3 larvae were in relatively poor condition, BD:SL ≤ 0.30. During this same period in Trials 1 and 2, mean BD:SL ≥ 0.31, suggesting that a BD:SL ratio of ≤ 0.30 in non-weaned dusky kob larvae is an indicator of a degree of starvation. A future study on the morphology and histology of the larval gastrointestinal tract, specifically the liver and intestines, and how this early weaning regime affects their ontogeny under differing temperature conditions this needed to investigate the validity of these initial data on dusky kob larvae condition.
- Full Text:
- Date Issued: 2019
The development of high-throughput assays to screen for potential anticancer and antimalarial compounds that target ADP-ribosylation factor 6 and its signalling machineries
- Authors: Khan, Farrah Dilshaad
- Date: 2019
- Subjects: ADP-ribosylation , Proteins -- Metabolism , Nucleoproteins , Malaria -- Chemotherapy , Cancer -- Chemotherapy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92952 , vital:30810
- Description: ADP-ribosylation factors (Arfs) are small GTP-binding proteins that cycle between active GTP-bound forms and inactive GDP-bound forms. GDP/GTP cycling is regulated by large families of guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). ArfGEFs activate Arfs by mediating the exchange of GDP for GTP, while ArfGAPs terminate Arf function by stimulating the hydrolysis of the terminal phosphate group of GTP. Arf6 is a major regulator of endocytic trafficking and reorganization of the actin cytoskeleton in eukaryotic organisms. Owing to its participation in wide range of fundamentally distinct cellular processes, Arf6 may be a drug target for cancer and malaria amongst other diseases. As with cancer cells, rapid growth and viability of eukaryotic pathogens likely places a heavy burden on their endocytic pathways and a critical reliance on Arf6 activity. A putative malarial homolog of Arf6 (PfArf6) localises to numerous puncta along the periphery of the parasite in the mature trophozoite life stage of the parasite (T. Swart, MSc dissertation). Owing to highly inefficient parasite transfection procedures and a relative shortage of well described and validated parasite organelle markers, the possible functions of PfArf6 were explored using HeLa cells as a surrogate model for parasites by fluorescence microscopy of cells transfected with GFP-tagged PfArf6. Partial co-localisation was observed with the mammalian markers HsArf6 and LC3, which suggested possible roles in Arf6-dependent endocytosis and autophagy, respectively. While these possible roles are currently under investigation in parasites, an overall long-term goal which was initiated in this study was to determine whether PfArf6 is a valid drug target. To chemically validate PfArf6 as a drug target, a potent inhibitor needs to be identified. This requires the development of assays that may be employed for high-throughput screening of compound libraries. To support this goal, a novel plate-based assay was developed using human Arf6. The assay relies on the selective binding of an Arf effector protein domain (GGA3) fused to glutathione-S-transferase (GST), to His-tagged Arf6 immobilised on a nickel-coated plate. The assay format was developed and could robustly distinguish HsArf6-GDP (inactive) from HsArf6-GTP (active). Furthermore, it could be employed to detect the deactivation of Arf6 by ArfGAP1-stimualted GTP hydrolysis, but not Arf6 activation by ARNO-stimulated GDP/GTP exchange (ARNO is an ArfGEF). The ArfGAP1 deactivation assay was chemically validated using a known ArfGAP inhibitor, QS11. An improved assay was developed that employs JIP4 as an Arf6-specific binding partner instead of GGA3. In addition to superior performance, the alternative assay format could potentially be exploited for cancer drug discovery, since Arf6-JIP4 interaction has been implicated in cancer cell invasion and metastasis. Both assays may be employed to explore alternative ArfGEFs and ArfGAPs that act on Arf6 and contribute to the advancement of cancer. In parallel experiments, where development of PfArf6 assays was the focus, several issues arose. Firstly, we could not prepare GDP- and GTP-bound forms of PfArf6 since EDTA-mediated nucleotide exchange appeared to irreversibly destabilise the protein. However, PfArf6 activation (i.e. the preparation of PfArf6-GTP) was possible when mediated by ARNO and assessed by tryptophan fluorescence kinetic assays, suggesting that PfArf6 may be expressed in GDP-bound form in E. coli. As with human Arf6, ARNO-mediated GDP/GTP exchange on PfArf6 was not detectable in the immobilised PfArf6-GGA interaction GST assay format. However, a more sensitive assay was developed which relies on the use of nickel-horseradish peroxidase to detect the binding of His-tagged PfArf6 to JIP4-GST immobilised on glutathione plates and could detect ARNO-mediated PfArf6 activation. Since we could not prepare PfArf6-GTP (that did not rely on the presence of the ArfGEF, ARNO), malarial ArfGAP deactivation studies were conducted using PfArf1 instead of PfArf6 in the GGA-GST interaction assay. Both PfArfGAP1and PfArfGAP2 stimulated GTP hydrolysis by PfArf1, but only the former was inhibited by the standard human ArfGAP inhibitor, QS11. The development of these simple, cost-effective assays can be used in the high-throughput screening of novel anticancer and antimalarial compounds that target Arf signalling machineries. In theory, the assay could be extended as a tool to identify novel inhibitors of the multitude of Arfs, ArfGEFs and ArfGAPs originating from any organism and hence has broad clinical significance.
- Full Text:
- Date Issued: 2019
- Authors: Khan, Farrah Dilshaad
- Date: 2019
- Subjects: ADP-ribosylation , Proteins -- Metabolism , Nucleoproteins , Malaria -- Chemotherapy , Cancer -- Chemotherapy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92952 , vital:30810
- Description: ADP-ribosylation factors (Arfs) are small GTP-binding proteins that cycle between active GTP-bound forms and inactive GDP-bound forms. GDP/GTP cycling is regulated by large families of guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs). ArfGEFs activate Arfs by mediating the exchange of GDP for GTP, while ArfGAPs terminate Arf function by stimulating the hydrolysis of the terminal phosphate group of GTP. Arf6 is a major regulator of endocytic trafficking and reorganization of the actin cytoskeleton in eukaryotic organisms. Owing to its participation in wide range of fundamentally distinct cellular processes, Arf6 may be a drug target for cancer and malaria amongst other diseases. As with cancer cells, rapid growth and viability of eukaryotic pathogens likely places a heavy burden on their endocytic pathways and a critical reliance on Arf6 activity. A putative malarial homolog of Arf6 (PfArf6) localises to numerous puncta along the periphery of the parasite in the mature trophozoite life stage of the parasite (T. Swart, MSc dissertation). Owing to highly inefficient parasite transfection procedures and a relative shortage of well described and validated parasite organelle markers, the possible functions of PfArf6 were explored using HeLa cells as a surrogate model for parasites by fluorescence microscopy of cells transfected with GFP-tagged PfArf6. Partial co-localisation was observed with the mammalian markers HsArf6 and LC3, which suggested possible roles in Arf6-dependent endocytosis and autophagy, respectively. While these possible roles are currently under investigation in parasites, an overall long-term goal which was initiated in this study was to determine whether PfArf6 is a valid drug target. To chemically validate PfArf6 as a drug target, a potent inhibitor needs to be identified. This requires the development of assays that may be employed for high-throughput screening of compound libraries. To support this goal, a novel plate-based assay was developed using human Arf6. The assay relies on the selective binding of an Arf effector protein domain (GGA3) fused to glutathione-S-transferase (GST), to His-tagged Arf6 immobilised on a nickel-coated plate. The assay format was developed and could robustly distinguish HsArf6-GDP (inactive) from HsArf6-GTP (active). Furthermore, it could be employed to detect the deactivation of Arf6 by ArfGAP1-stimualted GTP hydrolysis, but not Arf6 activation by ARNO-stimulated GDP/GTP exchange (ARNO is an ArfGEF). The ArfGAP1 deactivation assay was chemically validated using a known ArfGAP inhibitor, QS11. An improved assay was developed that employs JIP4 as an Arf6-specific binding partner instead of GGA3. In addition to superior performance, the alternative assay format could potentially be exploited for cancer drug discovery, since Arf6-JIP4 interaction has been implicated in cancer cell invasion and metastasis. Both assays may be employed to explore alternative ArfGEFs and ArfGAPs that act on Arf6 and contribute to the advancement of cancer. In parallel experiments, where development of PfArf6 assays was the focus, several issues arose. Firstly, we could not prepare GDP- and GTP-bound forms of PfArf6 since EDTA-mediated nucleotide exchange appeared to irreversibly destabilise the protein. However, PfArf6 activation (i.e. the preparation of PfArf6-GTP) was possible when mediated by ARNO and assessed by tryptophan fluorescence kinetic assays, suggesting that PfArf6 may be expressed in GDP-bound form in E. coli. As with human Arf6, ARNO-mediated GDP/GTP exchange on PfArf6 was not detectable in the immobilised PfArf6-GGA interaction GST assay format. However, a more sensitive assay was developed which relies on the use of nickel-horseradish peroxidase to detect the binding of His-tagged PfArf6 to JIP4-GST immobilised on glutathione plates and could detect ARNO-mediated PfArf6 activation. Since we could not prepare PfArf6-GTP (that did not rely on the presence of the ArfGEF, ARNO), malarial ArfGAP deactivation studies were conducted using PfArf1 instead of PfArf6 in the GGA-GST interaction assay. Both PfArfGAP1and PfArfGAP2 stimulated GTP hydrolysis by PfArf1, but only the former was inhibited by the standard human ArfGAP inhibitor, QS11. The development of these simple, cost-effective assays can be used in the high-throughput screening of novel anticancer and antimalarial compounds that target Arf signalling machineries. In theory, the assay could be extended as a tool to identify novel inhibitors of the multitude of Arfs, ArfGEFs and ArfGAPs originating from any organism and hence has broad clinical significance.
- Full Text:
- Date Issued: 2019
The diffusion of Max condoms among young women in KwaZulu Natal
- Authors: Donald, Charlene Chenaye
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/96870 , vital:31342
- Description: HIV is a disease that has a myriad of effects across different settings, and its prevalence varies across countries with different epidemiological drivers. The growing and disproportionate impact on young women has encouraged new ideas in HIV prevention strategies. The profusion of studies on HIV prevention strategies notwithstanding, the aspect of condom innovation has been largely ignored in literature. Drawing on the Diffusion of Innovation theory, this study examines how Max condoms have gained popularity among young women aged 18-24 years. The hypotheses are tested using an innovation-decision conceptual model and a comprehensive data set of 131 participants from rural, peri-urban and urban districts in KwaZulu Natal. Results reveal that the impact of marketing material and an effective public launch were significant in increasing Max condoms uptake, while the influence of peers and other members of one’s social system are critical for normalising the behaviour change. Young women have adopted Max condoms and uptake is continually influenced by positive perception of Max condoms’ relative advantage.
- Full Text:
- Date Issued: 2019
- Authors: Donald, Charlene Chenaye
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/96870 , vital:31342
- Description: HIV is a disease that has a myriad of effects across different settings, and its prevalence varies across countries with different epidemiological drivers. The growing and disproportionate impact on young women has encouraged new ideas in HIV prevention strategies. The profusion of studies on HIV prevention strategies notwithstanding, the aspect of condom innovation has been largely ignored in literature. Drawing on the Diffusion of Innovation theory, this study examines how Max condoms have gained popularity among young women aged 18-24 years. The hypotheses are tested using an innovation-decision conceptual model and a comprehensive data set of 131 participants from rural, peri-urban and urban districts in KwaZulu Natal. Results reveal that the impact of marketing material and an effective public launch were significant in increasing Max condoms uptake, while the influence of peers and other members of one’s social system are critical for normalising the behaviour change. Young women have adopted Max condoms and uptake is continually influenced by positive perception of Max condoms’ relative advantage.
- Full Text:
- Date Issued: 2019
The dispersion measure in broadband data from radio pulsars
- Authors: Rammala, Isabella
- Date: 2019
- Subjects: Pulsars , Radio astrophysics , Astrophsyics , Broadband communication systems
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67857 , vital:29157
- Description: Modern day radio telescopes make use of wideband receivers to take advantage of the broadband nature of the radio pulsar emission. We ask how does the use of such broadband pulsar data affect the measured pulsar dispersion measure (DM). Previous works have shown that, although the exact pulsar radio emission processes are not well understood, observations reveal evidence of possible frequency dependence on the emission altitudes in the pulsar magnetosphere, a phenomenon known as the radius-to-frequency mapping (RFM). This frequency dependence due to RFM can be embedded in the dispersive delay of the pulse profiles, normally interpreted as an interstellar effect (DM). Thus we interpret this intrinsic effect as an additional component δDM to the interstellar DM, and investigate how it can be statistically attributed to intrinsic profile evolution, as well as profile scattering. We make use of Monte-Carlo simulations of beam models to simulate realistic pulsar beams of various geometry, from which we generate intrinsic profiles at various frequency bands. The results show that the excess DM due to intrinsic profile evolution is more pronounced at high frequencies, whereas scattering dominates the excess DM at low frequency. The implications of these results are presented with relation to broadband pulsar timing.
- Full Text:
- Date Issued: 2019
- Authors: Rammala, Isabella
- Date: 2019
- Subjects: Pulsars , Radio astrophysics , Astrophsyics , Broadband communication systems
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67857 , vital:29157
- Description: Modern day radio telescopes make use of wideband receivers to take advantage of the broadband nature of the radio pulsar emission. We ask how does the use of such broadband pulsar data affect the measured pulsar dispersion measure (DM). Previous works have shown that, although the exact pulsar radio emission processes are not well understood, observations reveal evidence of possible frequency dependence on the emission altitudes in the pulsar magnetosphere, a phenomenon known as the radius-to-frequency mapping (RFM). This frequency dependence due to RFM can be embedded in the dispersive delay of the pulse profiles, normally interpreted as an interstellar effect (DM). Thus we interpret this intrinsic effect as an additional component δDM to the interstellar DM, and investigate how it can be statistically attributed to intrinsic profile evolution, as well as profile scattering. We make use of Monte-Carlo simulations of beam models to simulate realistic pulsar beams of various geometry, from which we generate intrinsic profiles at various frequency bands. The results show that the excess DM due to intrinsic profile evolution is more pronounced at high frequencies, whereas scattering dominates the excess DM at low frequency. The implications of these results are presented with relation to broadband pulsar timing.
- Full Text:
- Date Issued: 2019
The effect of age and culture on brand loyalty in the South African motor industry
- Authors: Hempel, Martin Johan
- Date: 2019
- Subjects: Brand loyalty -- South Africa , Automobile industry and trade -- South Africa , Consumer satisfaction -- South Africa , Consumer behavior -- South Africa , Older consumers -- South Africa , Consumers -- South Africa -- Cross-cultural studies
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/96859 , vital:31339
- Description: It has become imperative for companies in the motor industry to study and understand the notion of brand loyalty due to the many inherent advantages that it offers. Although existing literature provides extensive information on brand loyalty, the concept of brand loyalty is not constant across all industries. Factors such as age and culture also alter the effects of brand loyalty and the degree of brand loyalty generated within a consumer. Taking these variables into account, this study sets out to establish if age and culture have an effect on brand loyalty in the South African motor industry. The method in which motor companies emit marketing signals are also explored to establish if the emitted marketing signals are able to assist in the generation of brand loyalty. A South African real estate agent group agreed to participate in the research and became the sample population for the study. 190 successfully completed questionnaires were obtained in the data collection process and data with a Cronbach Alpha Coefficient (α) of 0.7662 proved that the data had satisfactory reliability. The data was processed and analysed in the statistical analysis program Stata. The study discovered that marketing signals don't assist in the generation of brand loyalty in the South African motor industry. It is suggested that it is more plausible that marketing signals can assist to maintain brand loyalty, rather than to generate brand loyalty. The study also discovered that culture does not have an effect on brand loyalty in the South African motor industry. However, after considering that the cultural distribution of the sample was significantly skewed, the sample is regarded as an unreliable test of the effect of culture on brand loyalty. The study also discovered that age doesn't have an effect brand loyalty in the South African motor industry. The researcher noted that the previously cognitively strenuous process of obtaining information has become more simplified by the internet and could potentially have reduced the generating of brand loyalty among older consumers. A final test was conducted to ascertain if relationships exist between the four stages of loyalty. The study suggested that all four loyalty stages are connected which confirms that brand loyalty is generated by both attitudinal and behavioural dimensions.
- Full Text:
- Date Issued: 2019
- Authors: Hempel, Martin Johan
- Date: 2019
- Subjects: Brand loyalty -- South Africa , Automobile industry and trade -- South Africa , Consumer satisfaction -- South Africa , Consumer behavior -- South Africa , Older consumers -- South Africa , Consumers -- South Africa -- Cross-cultural studies
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/96859 , vital:31339
- Description: It has become imperative for companies in the motor industry to study and understand the notion of brand loyalty due to the many inherent advantages that it offers. Although existing literature provides extensive information on brand loyalty, the concept of brand loyalty is not constant across all industries. Factors such as age and culture also alter the effects of brand loyalty and the degree of brand loyalty generated within a consumer. Taking these variables into account, this study sets out to establish if age and culture have an effect on brand loyalty in the South African motor industry. The method in which motor companies emit marketing signals are also explored to establish if the emitted marketing signals are able to assist in the generation of brand loyalty. A South African real estate agent group agreed to participate in the research and became the sample population for the study. 190 successfully completed questionnaires were obtained in the data collection process and data with a Cronbach Alpha Coefficient (α) of 0.7662 proved that the data had satisfactory reliability. The data was processed and analysed in the statistical analysis program Stata. The study discovered that marketing signals don't assist in the generation of brand loyalty in the South African motor industry. It is suggested that it is more plausible that marketing signals can assist to maintain brand loyalty, rather than to generate brand loyalty. The study also discovered that culture does not have an effect on brand loyalty in the South African motor industry. However, after considering that the cultural distribution of the sample was significantly skewed, the sample is regarded as an unreliable test of the effect of culture on brand loyalty. The study also discovered that age doesn't have an effect brand loyalty in the South African motor industry. The researcher noted that the previously cognitively strenuous process of obtaining information has become more simplified by the internet and could potentially have reduced the generating of brand loyalty among older consumers. A final test was conducted to ascertain if relationships exist between the four stages of loyalty. The study suggested that all four loyalty stages are connected which confirms that brand loyalty is generated by both attitudinal and behavioural dimensions.
- Full Text:
- Date Issued: 2019
The effect of bait on fine-scale habitat associations of reef fish investigated with remote underwater video systems
- Authors: Schmidt, Nicholas C
- Date: 2019
- Subjects: Baited remote underwater stereo-video systems (stereo-BRUVs) , Remote underwater stereo-video systems , Underwater videography in wildlife monitoring -- South Africa -- Tsitsikamma , Fish stock assessment -- South Africa -- Tsitsikamma , Fish populations -- Monitoring -- South Africa -- Tsitsikamma , Fishes -- Habitat -- South Africa -- Tsitsikamma
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68380 , vital:29249
- Description: Establishing the associations between fish and their habitats can aid in the monitoring of fish stocks and the design of effective marine protected areas (MPAs). Baited remote underwater stereo-video systems (stereo-BRUVs) are now commonly used to asses fish populations. The habitats seen in the video footage of stereo-BRUVs can be used to link fish fauna to preferred habitat types. However, the application of bait potentially attracts fish from surrounding habitats, and might result in a biased understanding of fish–habitat associations. A field study was conducted in the Tsitsikamma National Park MPA to determine the effect of bait on fine-scale fish–habitat associations, using remote photographic and video methods. The study was conducted over the summer season of 2015 and 2016. Data were collected within a 1x1 km shallow (9–44 m) reef complex. Within the sampling area, 944 photo-quadrats of the macrobenthos were taken 30 m apart by means of a drop camera. By separating the macrobenthos into broad taxonomic groups, five habitat types were identified, namely Shallow Sand, Shallow Reef, Deep Reef, Deep Sand and Patch Reef. The results show that even on a fine scale, depth is an important predictor of macrobenthic distribution and assemblage structure. Baited (stereo-BRUVs) and unbaited (stereo-RUVs) surveys were then conducted to sample the fish community in the same area during the period under study. Higher abundances of fish were observed in reef than in sandy habitats, and bait was seen to have a positive effect on species richness and fish abundance. When comparing habitats, fish abundance and composition on reef habitats were significantly different from sand habitats. This was observed in both the stereo-RUVs and stereo-BRUVs methods. High counts of roman (Chrysoblephus laticeps), fransmadam (Boopsoidea inornata) and steentjie (Spondyliosoma emarginatum) in reef habitats were contrasted by high counts of white sea catfish (Galeichthys feliceps), evil-eye puffer (Amblyrhynchotes honckenii) and lesser guitarfish (Rhinecanthus annulatus) in sandy habitats. Overall, the underlying patterns in fish diversity recorded with the two video methods were generally comparable. However, stereo-RUVs appeared to be unable to detect species that were present in sand habitats, while stereo-BRUVs increased the number and abundance of species recorded in all habitat types. In the stereo-RUVs footage, differences between reef habitats were dampened by the presence of highly abundant fish species. In the stereo-BRUVs footage, although bait appeared to have an effect on the observed fish assemblage, this manifested in an increase in species richness, higher fish abundances and a better overall ability to detect fish–habitat relationships. As such, stereo-BRUVs are considered a robust, effective and recommended method for detecting fish–habitat relationships, even over a fine scale.
- Full Text:
- Date Issued: 2019
- Authors: Schmidt, Nicholas C
- Date: 2019
- Subjects: Baited remote underwater stereo-video systems (stereo-BRUVs) , Remote underwater stereo-video systems , Underwater videography in wildlife monitoring -- South Africa -- Tsitsikamma , Fish stock assessment -- South Africa -- Tsitsikamma , Fish populations -- Monitoring -- South Africa -- Tsitsikamma , Fishes -- Habitat -- South Africa -- Tsitsikamma
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68380 , vital:29249
- Description: Establishing the associations between fish and their habitats can aid in the monitoring of fish stocks and the design of effective marine protected areas (MPAs). Baited remote underwater stereo-video systems (stereo-BRUVs) are now commonly used to asses fish populations. The habitats seen in the video footage of stereo-BRUVs can be used to link fish fauna to preferred habitat types. However, the application of bait potentially attracts fish from surrounding habitats, and might result in a biased understanding of fish–habitat associations. A field study was conducted in the Tsitsikamma National Park MPA to determine the effect of bait on fine-scale fish–habitat associations, using remote photographic and video methods. The study was conducted over the summer season of 2015 and 2016. Data were collected within a 1x1 km shallow (9–44 m) reef complex. Within the sampling area, 944 photo-quadrats of the macrobenthos were taken 30 m apart by means of a drop camera. By separating the macrobenthos into broad taxonomic groups, five habitat types were identified, namely Shallow Sand, Shallow Reef, Deep Reef, Deep Sand and Patch Reef. The results show that even on a fine scale, depth is an important predictor of macrobenthic distribution and assemblage structure. Baited (stereo-BRUVs) and unbaited (stereo-RUVs) surveys were then conducted to sample the fish community in the same area during the period under study. Higher abundances of fish were observed in reef than in sandy habitats, and bait was seen to have a positive effect on species richness and fish abundance. When comparing habitats, fish abundance and composition on reef habitats were significantly different from sand habitats. This was observed in both the stereo-RUVs and stereo-BRUVs methods. High counts of roman (Chrysoblephus laticeps), fransmadam (Boopsoidea inornata) and steentjie (Spondyliosoma emarginatum) in reef habitats were contrasted by high counts of white sea catfish (Galeichthys feliceps), evil-eye puffer (Amblyrhynchotes honckenii) and lesser guitarfish (Rhinecanthus annulatus) in sandy habitats. Overall, the underlying patterns in fish diversity recorded with the two video methods were generally comparable. However, stereo-RUVs appeared to be unable to detect species that were present in sand habitats, while stereo-BRUVs increased the number and abundance of species recorded in all habitat types. In the stereo-RUVs footage, differences between reef habitats were dampened by the presence of highly abundant fish species. In the stereo-BRUVs footage, although bait appeared to have an effect on the observed fish assemblage, this manifested in an increase in species richness, higher fish abundances and a better overall ability to detect fish–habitat relationships. As such, stereo-BRUVs are considered a robust, effective and recommended method for detecting fish–habitat relationships, even over a fine scale.
- Full Text:
- Date Issued: 2019
The effectiveness of sandplay therapy with a Xhosa child
- Authors: Snelgar, Orrin Glenn
- Date: 2019
- Subjects: Sandplay -- Therapeutic use -- Case studies -- South Africa , Play therapy -- Case studies -- South Africa , Child psychotherapy -- Case studies -- South Africa , Children, Black -- Psychology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/179168 , vital:39876
- Description: This case study sought to determine whether Kalffian Sandtray Therapy was effective with a Xhosa child. In the context of ongoing discussions surrounding evidence-based practice and culturally appropriate interventions, no published research has yet explored the effectiveness of this classical tool within this significant South African demographic. In an effort to address this omission, the research adopted a mixed methods approach where Kalffian analysis of the sandplay process was evaluated in conjunction with quantitative measures (the Strengths and Difficulties Questionnaire and the Young Person’s Clinical Outcomes in Routine Evaluation). The results of this triangulation revealed a complex picture of improved interpersonal functioning and stagnant (or worsened) emotional wellbeing after five sessions. Contextualised interpretations of these findings are discussed and recommendations made for future sandplay practice and research in the South African context.
- Full Text:
- Date Issued: 2019
- Authors: Snelgar, Orrin Glenn
- Date: 2019
- Subjects: Sandplay -- Therapeutic use -- Case studies -- South Africa , Play therapy -- Case studies -- South Africa , Child psychotherapy -- Case studies -- South Africa , Children, Black -- Psychology -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/179168 , vital:39876
- Description: This case study sought to determine whether Kalffian Sandtray Therapy was effective with a Xhosa child. In the context of ongoing discussions surrounding evidence-based practice and culturally appropriate interventions, no published research has yet explored the effectiveness of this classical tool within this significant South African demographic. In an effort to address this omission, the research adopted a mixed methods approach where Kalffian analysis of the sandplay process was evaluated in conjunction with quantitative measures (the Strengths and Difficulties Questionnaire and the Young Person’s Clinical Outcomes in Routine Evaluation). The results of this triangulation revealed a complex picture of improved interpersonal functioning and stagnant (or worsened) emotional wellbeing after five sessions. Contextualised interpretations of these findings are discussed and recommendations made for future sandplay practice and research in the South African context.
- Full Text:
- Date Issued: 2019
The experiences of health service providers working with children with physical disabilities and their caregivers in the Eastern Cape
- Authors: Mathaba, Yollandah
- Date: 2019
- Subjects: Children with disabilities -- South Africa -- Eastern Cape , Caregivers -- South Africa -- Eastern Cape -- Case studies , Caregivers -- Psychology , Children with disabilities -- Care
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/76299 , vital:30545
- Description: The prevalence of childhood disability in South Africa is significant. In an attempt to meet the constitutional rights of children with disabilities, there are a variety of services available for children with disabilities. These services are aimed at rehabilitating children with disabilities and integrating them in society. Amongst such services are health services. Due to the nature of some childhood disabilities, it is recommended that they should be seen by a multidisciplinary team. While the field of childhood disability has been researched extensively. Limited research has been conducted on the experiences of health service providers working with children with disabilities and their caregivers. The current study explored the experiences of health service providers working with children with disabilities and their caregivers in the Eastern Cape. To achieve this aim, the study employed Interpretative Phenomenological Analysis (IPA). Five participants were recruited using purposive and snowball sampling methods. Semi-structured interviews were used to allow participants to freely share their experiences of working with children with disabilities and their caregivers. The interviews were audio recorded and transcribed for analysis purpose. The analysis process generated five master themes namely: Positive experiences of their work; negative experiences of their work; perception of their role as changing over time; managing challenges in their work; and experiences of a service learning programme as complementary to their work. The findings of the study highlighted both the positive experiences and the negative experiences of their work. On the one hand, the participants reported positive affect and that they found their work meaningful. They also reported a sense of feeling supported by fellow colleagues and enjoying their work at the clinics. On the other hand, the participants reported negative affect in relation to their wok difficulties such as feelings of frustration, feelings of being unappreciated by management and finding the work distressing. The participants reported that professional and emotional growth in conjunction with perspective taking contributed to developing better coping mechanisms. A service learning programme offered in the community was experienced as a good contribution to the work done at the clinics and distinguished as addressing the emotional needs of the caregivers which cannot be addressed at the clinics. The findings of the study supports and expands the literature on the experiences of health service providers working with children with disabilities in South Africa.
- Full Text:
- Date Issued: 2019
- Authors: Mathaba, Yollandah
- Date: 2019
- Subjects: Children with disabilities -- South Africa -- Eastern Cape , Caregivers -- South Africa -- Eastern Cape -- Case studies , Caregivers -- Psychology , Children with disabilities -- Care
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/76299 , vital:30545
- Description: The prevalence of childhood disability in South Africa is significant. In an attempt to meet the constitutional rights of children with disabilities, there are a variety of services available for children with disabilities. These services are aimed at rehabilitating children with disabilities and integrating them in society. Amongst such services are health services. Due to the nature of some childhood disabilities, it is recommended that they should be seen by a multidisciplinary team. While the field of childhood disability has been researched extensively. Limited research has been conducted on the experiences of health service providers working with children with disabilities and their caregivers. The current study explored the experiences of health service providers working with children with disabilities and their caregivers in the Eastern Cape. To achieve this aim, the study employed Interpretative Phenomenological Analysis (IPA). Five participants were recruited using purposive and snowball sampling methods. Semi-structured interviews were used to allow participants to freely share their experiences of working with children with disabilities and their caregivers. The interviews were audio recorded and transcribed for analysis purpose. The analysis process generated five master themes namely: Positive experiences of their work; negative experiences of their work; perception of their role as changing over time; managing challenges in their work; and experiences of a service learning programme as complementary to their work. The findings of the study highlighted both the positive experiences and the negative experiences of their work. On the one hand, the participants reported positive affect and that they found their work meaningful. They also reported a sense of feeling supported by fellow colleagues and enjoying their work at the clinics. On the other hand, the participants reported negative affect in relation to their wok difficulties such as feelings of frustration, feelings of being unappreciated by management and finding the work distressing. The participants reported that professional and emotional growth in conjunction with perspective taking contributed to developing better coping mechanisms. A service learning programme offered in the community was experienced as a good contribution to the work done at the clinics and distinguished as addressing the emotional needs of the caregivers which cannot be addressed at the clinics. The findings of the study supports and expands the literature on the experiences of health service providers working with children with disabilities in South Africa.
- Full Text:
- Date Issued: 2019