An investigation into the interaction partners of the scaffold protein human CNK1 in the NF-κB pathway
- Authors: Moodley, Holisha
- Date: 2019
- Subjects: CNK1 , Scaffold proteins
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/96031 , vital:31228
- Description: The protein connector enhancer of KSR1 (CNK1) plays a role in a number of signalling pathways including those involved in cell proliferation, cell growth and differentiation. De-regulation of these pathways has been linked to the promotion of oncogenic signalling. The involvement of CNK1 in all of these diverse pathways indicates a need to better understand the role of this protein within the cell and within key signalling networks. The research provides a platform to understand the intricate relationships that occur between these key signalling networks with the potential to identify new drug targets. CNK1 is multifunctional scaffolding protein that has binding domains that mediate and co-ordinate signalling within the MAPK, Hippo, PI3K/AKT, JNK and NF-κB pathways as well as downstream of the AT2 receptor. The activity of CNK1 is regulated through its interactions with a range of different binding partners within these pathways. Of particular interest to this research is the role of CNK1 in NF-κB signalling. The deregulation of the NF-κB pathway is implicated in chronic inflammation, tissue damage and induction of cervical and breast cancer. CNK1 has been reported to regulate the non-canonical branch of the NF-κB pathway, upstream of the IKK complex however new findings lead to uncertainty about these conclusions. In addition, the interacting partner of CNK1 in the NF-κB pathway has not been elucidated. In this thesis, we aim to identify the binding partners of CNK1 in the NF-κB pathway. First, we validate an epitope-tagged CNK1-expression construct to express elevated levels of CNK1 in cervical cancer cells. We report that the expression of myc-CNK1 is comparable to endogenous CNK1. Cells expressing elevated CNK1 levels were used in traditional co-immunoprecipitation reactions to identify potential CNK1-interacting proteins. We present data that indicates a potential role for NIK in the CNK1 signalling complex. We discuss the weaknesses of the traditional co-immunoprecipitation reactions and design an alternative co-immunoprecipitation technique with which to study CNK1-interacting partners. In this system, a promiscuous biotin ligase fused to the protein sequence for CNK1 (BirA-CNK1) is used to label proteins proximal to CNK1 with biotin. Using this BirA- CNK1-expressing construct in cervical cancer cells, we demonstrate that CNK1 interacts with IKKα-IKKβ in the NF-κB pathway.
- Full Text:
- Authors: Moodley, Holisha
- Date: 2019
- Subjects: CNK1 , Scaffold proteins
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/96031 , vital:31228
- Description: The protein connector enhancer of KSR1 (CNK1) plays a role in a number of signalling pathways including those involved in cell proliferation, cell growth and differentiation. De-regulation of these pathways has been linked to the promotion of oncogenic signalling. The involvement of CNK1 in all of these diverse pathways indicates a need to better understand the role of this protein within the cell and within key signalling networks. The research provides a platform to understand the intricate relationships that occur between these key signalling networks with the potential to identify new drug targets. CNK1 is multifunctional scaffolding protein that has binding domains that mediate and co-ordinate signalling within the MAPK, Hippo, PI3K/AKT, JNK and NF-κB pathways as well as downstream of the AT2 receptor. The activity of CNK1 is regulated through its interactions with a range of different binding partners within these pathways. Of particular interest to this research is the role of CNK1 in NF-κB signalling. The deregulation of the NF-κB pathway is implicated in chronic inflammation, tissue damage and induction of cervical and breast cancer. CNK1 has been reported to regulate the non-canonical branch of the NF-κB pathway, upstream of the IKK complex however new findings lead to uncertainty about these conclusions. In addition, the interacting partner of CNK1 in the NF-κB pathway has not been elucidated. In this thesis, we aim to identify the binding partners of CNK1 in the NF-κB pathway. First, we validate an epitope-tagged CNK1-expression construct to express elevated levels of CNK1 in cervical cancer cells. We report that the expression of myc-CNK1 is comparable to endogenous CNK1. Cells expressing elevated CNK1 levels were used in traditional co-immunoprecipitation reactions to identify potential CNK1-interacting proteins. We present data that indicates a potential role for NIK in the CNK1 signalling complex. We discuss the weaknesses of the traditional co-immunoprecipitation reactions and design an alternative co-immunoprecipitation technique with which to study CNK1-interacting partners. In this system, a promiscuous biotin ligase fused to the protein sequence for CNK1 (BirA-CNK1) is used to label proteins proximal to CNK1 with biotin. Using this BirA- CNK1-expressing construct in cervical cancer cells, we demonstrate that CNK1 interacts with IKKα-IKKβ in the NF-κB pathway.
- Full Text:
An investigation of learning and emerging knowledge in the Mpophomeni Sanitation Education Project, Howick, KwaZulu-Natal
- Authors: Boothway, Reinetta Louina
- Date: 2019
- Subjects: Environmental education -- South Africa , Mpophomeni Sanitation Education Project (South Africa) , Water quality management -- Study and teaching -- South Africa , Knowledge and learning
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/115377 , vital:34121
- Description: This study took place within the broader context of water resources management in South Africa. With the democratisation of water stewardship through an enabling international and South African water policy landscape, an opportunity opened up for citizens to participate in the effective management of their own water resources. In this context, a community-engaged citizen science project known as the Mpophomeni Sanitation Education Project emerged to demonstrate how a diverse range of knowledge agents can work and learn together to better manage their water resources and address problems of sewage pollution threatening their provincial water source. The following study aimed to shed light on the learning and emerging knowledge in the MSEP. The study was conducted in three phases. Wenger’s Communities of Practice (CoP) theory provided a lens to look at Phase One, which aimed to answer the following sub-question: Is the MSEP a CoP? Wenger’s CoP theory also assisted with the investigation during Phase Two, which looked at the following question: What is the nature of learning in the MSEP? Social realist theories of knowledge and education, and Tàbara and Chabay with their Ideal Type (IT) worldviews, provided suitable lenses for Phase Three’s investigation of the following question: What is the nature of emerging knowledge in the MSEP? The main finding for Phase One is that the MSEP does function as a CoP. With its strong focus on relationships, it’s clearly defined joint enterprise of solving the problem of sewage pollution, individual and joint commitment to engage with the problem and the sharing of a repertoire of tools, ideas and practices it is cultivating a culture conducive to purposeful learning. Regarding the exploration of the nature of learning in Phase Two, findings confirming the engagement of identity with learning and the importance of context for meaning-making emerged. Finally, study findings about the nature of knowledge in the MSEP found that the knowledge practices in the MSEP that are both social and epistemic in nature are produced by a diverse range of knowledge agents in an open knowledge space.
- Full Text:
- Authors: Boothway, Reinetta Louina
- Date: 2019
- Subjects: Environmental education -- South Africa , Mpophomeni Sanitation Education Project (South Africa) , Water quality management -- Study and teaching -- South Africa , Knowledge and learning
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/115377 , vital:34121
- Description: This study took place within the broader context of water resources management in South Africa. With the democratisation of water stewardship through an enabling international and South African water policy landscape, an opportunity opened up for citizens to participate in the effective management of their own water resources. In this context, a community-engaged citizen science project known as the Mpophomeni Sanitation Education Project emerged to demonstrate how a diverse range of knowledge agents can work and learn together to better manage their water resources and address problems of sewage pollution threatening their provincial water source. The following study aimed to shed light on the learning and emerging knowledge in the MSEP. The study was conducted in three phases. Wenger’s Communities of Practice (CoP) theory provided a lens to look at Phase One, which aimed to answer the following sub-question: Is the MSEP a CoP? Wenger’s CoP theory also assisted with the investigation during Phase Two, which looked at the following question: What is the nature of learning in the MSEP? Social realist theories of knowledge and education, and Tàbara and Chabay with their Ideal Type (IT) worldviews, provided suitable lenses for Phase Three’s investigation of the following question: What is the nature of emerging knowledge in the MSEP? The main finding for Phase One is that the MSEP does function as a CoP. With its strong focus on relationships, it’s clearly defined joint enterprise of solving the problem of sewage pollution, individual and joint commitment to engage with the problem and the sharing of a repertoire of tools, ideas and practices it is cultivating a culture conducive to purposeful learning. Regarding the exploration of the nature of learning in Phase Two, findings confirming the engagement of identity with learning and the importance of context for meaning-making emerged. Finally, study findings about the nature of knowledge in the MSEP found that the knowledge practices in the MSEP that are both social and epistemic in nature are produced by a diverse range of knowledge agents in an open knowledge space.
- Full Text:
An investigation of the security of passwords derived from African languages
- Authors: Sishi, Sibusiso Teboho
- Date: 2019
- Subjects: Computers -- Access control -- Passwords , Computer users -- Attitudes , Internet -- Access control , Internet -- Security measures , Internet -- Management , Data protection
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163273 , vital:41024
- Description: Password authentication has become ubiquitous in the cyber age. To-date, there have been several studies on country based passwords by authors who studied, amongst others, English, Finnish, Italian and Chinese based passwords. However, there has been a lack of focused study on the type of passwords that are being created in Africa and whether there are benefits in creating passwords in an African language. For this research, password databases containing LAN Manager (LM) and NT LAN Manager (NTLM) hashes extracted from South African organisations in a variety of sectors in the economy, were obtained to gain an understanding of user behaviour in creating passwords. Analysis of the passwords obtained from these hashes (using several cracking methods) showed that many organisational passwords are based on the English language. This is understandable considering that the business language in South Africa is English even though South Africa has 11 official languages. African language based passwords were derived from known English weak passwords and some of the passwords were appended with numbers and special characters. The African based passwords created using eight Southern African languages were then uploaded to the Internet to test the security around using passwords based on African languages. Since most of the passwords were able to be cracked by third party researchers, we conclude that any password that is derived from known weak English words marked no improvement in the security of a password written in an African language, especially the more widely spoken languages, namely, isiZulu, isiXhosa and Setswana.
- Full Text:
- Authors: Sishi, Sibusiso Teboho
- Date: 2019
- Subjects: Computers -- Access control -- Passwords , Computer users -- Attitudes , Internet -- Access control , Internet -- Security measures , Internet -- Management , Data protection
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163273 , vital:41024
- Description: Password authentication has become ubiquitous in the cyber age. To-date, there have been several studies on country based passwords by authors who studied, amongst others, English, Finnish, Italian and Chinese based passwords. However, there has been a lack of focused study on the type of passwords that are being created in Africa and whether there are benefits in creating passwords in an African language. For this research, password databases containing LAN Manager (LM) and NT LAN Manager (NTLM) hashes extracted from South African organisations in a variety of sectors in the economy, were obtained to gain an understanding of user behaviour in creating passwords. Analysis of the passwords obtained from these hashes (using several cracking methods) showed that many organisational passwords are based on the English language. This is understandable considering that the business language in South Africa is English even though South Africa has 11 official languages. African language based passwords were derived from known English weak passwords and some of the passwords were appended with numbers and special characters. The African based passwords created using eight Southern African languages were then uploaded to the Internet to test the security around using passwords based on African languages. Since most of the passwords were able to be cracked by third party researchers, we conclude that any password that is derived from known weak English words marked no improvement in the security of a password written in an African language, especially the more widely spoken languages, namely, isiZulu, isiXhosa and Setswana.
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An investigation of the teaching of writing in Grade-9 English first-language classrooms: a case study of a selected government school in Namibia
- Martins, Simone Alexandra Domingues
- Authors: Martins, Simone Alexandra Domingues
- Date: 2019
- Subjects: English language -- Rhetoric -- Study and teaching -- Namibia , English language -- Study and teaching (Secondary) -- Namibia , English language == Composition and exercises -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/92280 , vital:30699
- Description: The pedagogical practice choices teachers make when teaching writing in Grade-9 English first- language classrooms, as well as the extent to which these pedagogical practices appear to enable or constrain learners’ acquisition of writing skills as per grade-specific curricular expectations, are the focus of the study. It draws from Bernstein’s (1971) curriculum and society theory, as well as genre theory. Located within the qualitative case study approach, it is designed to investigate the reasons for Grade-9 English first-language learners’ underperformance in Paper 2, the composition component of the Namibian external examinations. Drawing from the interpretivist paradigm, the study uses one-on-one interviews, semi-structured classroom observations, as well as documentary evidence of the Namibian English first-language syllabus and examples of learners’ written work, to generate data. The research site and study participants were purposefully selected. The study involves two Grade-9 English first-language teachers and classrooms at one Namibian High School, and took place from the second to the third terms of 2017.
- Full Text:
- Authors: Martins, Simone Alexandra Domingues
- Date: 2019
- Subjects: English language -- Rhetoric -- Study and teaching -- Namibia , English language -- Study and teaching (Secondary) -- Namibia , English language == Composition and exercises -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/92280 , vital:30699
- Description: The pedagogical practice choices teachers make when teaching writing in Grade-9 English first- language classrooms, as well as the extent to which these pedagogical practices appear to enable or constrain learners’ acquisition of writing skills as per grade-specific curricular expectations, are the focus of the study. It draws from Bernstein’s (1971) curriculum and society theory, as well as genre theory. Located within the qualitative case study approach, it is designed to investigate the reasons for Grade-9 English first-language learners’ underperformance in Paper 2, the composition component of the Namibian external examinations. Drawing from the interpretivist paradigm, the study uses one-on-one interviews, semi-structured classroom observations, as well as documentary evidence of the Namibian English first-language syllabus and examples of learners’ written work, to generate data. The research site and study participants were purposefully selected. The study involves two Grade-9 English first-language teachers and classrooms at one Namibian High School, and took place from the second to the third terms of 2017.
- Full Text:
Analyzing the Anthropogenic Allee Effect in cycad (Encephalartos species) populations in South Africa: an evaluation of illegal trade and conservation policy
- Authors: Earle, Sasha
- Date: 2019
- Subjects: Allee effect , 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 , Masters , Mcom
- Identifier: http://hdl.handle.net/10962/95565 , vital:31171
- Description: South Africa is a country known for rich biodiversity and ecosystems across the land and seascape. South Africa is one of the global hotspots for cycad diversity. Cycads are known to be the world’s most threatened plant species; declining in South Africa at a rapid pace, with threat of extinction in the wild. The main factor being harvesting from the wild for private collections. Rare cycad species’ are especially sought after by collectors. Economic theory assumes that the exploitation of a species is unlikely to result in extinction due to the increasing costs of finding the last few individuals of a species. However, the theory of the Anthropogenic Allee Effect (AAE) suggests that if consumers place a disproportionate value on a rare species’, a cycle may result whereby increased exploitation decreases population size, increasing the value of the species and, consequently, leading to its extinction in the wild. This hypothesis was tested for 37 Encephalartos species using data collected on wild populations, auction prices and the IUCN Red List status for the year 2010. It was hypothesised that an AAE was present within Encephalartos species, as three species have already gone extinct in the wild. The price per centimetre was positively correlated to the rarity of the species and the price per centimetre was negatively correlated to the wild population size. The results suggest a trend of an AAE for the year 2010. Adequate conservation policies are needed to reduce the effects of demand on illegal harvesting and prevent extinction in the wild. The effect of rarity needs to be taken into account to ensure successfulness of such policies. The most recent conservation policy implemented to protect cycads in South Africa is the Strategy and Action for the Management of Cycads in South Africa, which was introduced in 2016. The successfulness of this policy cannot, however, be analysed due to a lack of census data following its implementation.
- Full Text:
- Authors: Earle, Sasha
- Date: 2019
- Subjects: Allee effect , 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 , Masters , Mcom
- Identifier: http://hdl.handle.net/10962/95565 , vital:31171
- Description: South Africa is a country known for rich biodiversity and ecosystems across the land and seascape. South Africa is one of the global hotspots for cycad diversity. Cycads are known to be the world’s most threatened plant species; declining in South Africa at a rapid pace, with threat of extinction in the wild. The main factor being harvesting from the wild for private collections. Rare cycad species’ are especially sought after by collectors. Economic theory assumes that the exploitation of a species is unlikely to result in extinction due to the increasing costs of finding the last few individuals of a species. However, the theory of the Anthropogenic Allee Effect (AAE) suggests that if consumers place a disproportionate value on a rare species’, a cycle may result whereby increased exploitation decreases population size, increasing the value of the species and, consequently, leading to its extinction in the wild. This hypothesis was tested for 37 Encephalartos species using data collected on wild populations, auction prices and the IUCN Red List status for the year 2010. It was hypothesised that an AAE was present within Encephalartos species, as three species have already gone extinct in the wild. The price per centimetre was positively correlated to the rarity of the species and the price per centimetre was negatively correlated to the wild population size. The results suggest a trend of an AAE for the year 2010. Adequate conservation policies are needed to reduce the effects of demand on illegal harvesting and prevent extinction in the wild. The effect of rarity needs to be taken into account to ensure successfulness of such policies. The most recent conservation policy implemented to protect cycads in South Africa is the Strategy and Action for the Management of Cycads in South Africa, which was introduced in 2016. The successfulness of this policy cannot, however, be analysed due to a lack of census data following its implementation.
- Full Text:
Arbuscular mycorrhizal fungi as a bio-indicator of soil health under agricultural management practices in South Africa
- Authors: Sekgota, Wendy Maphefo
- Date: 2019
- Subjects: Soils -- Quality -- South Africa , Soil fertility -- South Africa , Fungi in agriculture -- South Africa , Mycorrhizal fungi , Vesicular-arbuscular mycorrhizas , Fungi -- Spores , Soils -- Agricultural chemical content
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72161 , vital:30011
- Description: This study investigated the activity of arbuscular mycorrhizal (AM) fungi as a potential biological indicator of soil health under conventional and conservation agricultural management in South Africa. An experimental trial consisting of three replicates plots under conventional and reduced tillage subdivided into twelve treatments of six crops and two fertilizer inputs was assessed over four growing seasons for various AM fungal parameters such as spore density, most probable number (MPN) of propagules percentage root colonisation and easily extractable glomalin (EEG). Cropping combinations were maize monoculture; maize soybean rotation; maize cowpea rotation; maize cowpea intercropping; maize oats intercropping and maize vetch intercropping. Resident AM fungal spore numbers and EEG protein levels were very low and no root colonization was recorded in the first two growing seasons. These findings prompted the need for the inoculation of the study site in the third growing season with a commercial AM fungal product (MycorootTM). Spore numbers, EEG concentrations and percentage root colonisation increased 8 weeks after inoculation but were significantly reduced in the fourth growing season that was not inoculated. MPN infectivity increased with inoculation particularly under conventional tillage and maize monoculture. Resident spore taxa were morphologically identified into three genera Gigaspora, Scutellospora, and Glomus. For the first two growing seasons, the maize roots were heavily colonized by a pathogenic fungus after mycorrhizal inoculation no evidence of pathogenic fungi was observed. In the fourth growing season which did not receive inoculation, root colonization started to decline. Reduced tillage, high fertilizer input combined with maize cowpea rotation (MC) and maize hairy vetch intercropping (Mv) had a significant effect (P = 0.01) on AM fungal spore numbers. Cropping systems and high fertilizer input had a significant effect on EEG concentrations in the second growing season. Overall, fertilizer application and crop type had implications for mycorrhizal activity. The soil health status in this study site was deemed low as measured by the impaired mycorrhizal activity due to agricultural management practices. Field inoculation combined with classical and molecular tools could provide a more realistic assessment of the effect of agricultural management practices on AM fungi as potential bioindicators of soil health. Therefore, AM fungi could be used as bioindicators of soil health under agricultural management practices in South African soil conditions.
- Full Text:
- Authors: Sekgota, Wendy Maphefo
- Date: 2019
- Subjects: Soils -- Quality -- South Africa , Soil fertility -- South Africa , Fungi in agriculture -- South Africa , Mycorrhizal fungi , Vesicular-arbuscular mycorrhizas , Fungi -- Spores , Soils -- Agricultural chemical content
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72161 , vital:30011
- Description: This study investigated the activity of arbuscular mycorrhizal (AM) fungi as a potential biological indicator of soil health under conventional and conservation agricultural management in South Africa. An experimental trial consisting of three replicates plots under conventional and reduced tillage subdivided into twelve treatments of six crops and two fertilizer inputs was assessed over four growing seasons for various AM fungal parameters such as spore density, most probable number (MPN) of propagules percentage root colonisation and easily extractable glomalin (EEG). Cropping combinations were maize monoculture; maize soybean rotation; maize cowpea rotation; maize cowpea intercropping; maize oats intercropping and maize vetch intercropping. Resident AM fungal spore numbers and EEG protein levels were very low and no root colonization was recorded in the first two growing seasons. These findings prompted the need for the inoculation of the study site in the third growing season with a commercial AM fungal product (MycorootTM). Spore numbers, EEG concentrations and percentage root colonisation increased 8 weeks after inoculation but were significantly reduced in the fourth growing season that was not inoculated. MPN infectivity increased with inoculation particularly under conventional tillage and maize monoculture. Resident spore taxa were morphologically identified into three genera Gigaspora, Scutellospora, and Glomus. For the first two growing seasons, the maize roots were heavily colonized by a pathogenic fungus after mycorrhizal inoculation no evidence of pathogenic fungi was observed. In the fourth growing season which did not receive inoculation, root colonization started to decline. Reduced tillage, high fertilizer input combined with maize cowpea rotation (MC) and maize hairy vetch intercropping (Mv) had a significant effect (P = 0.01) on AM fungal spore numbers. Cropping systems and high fertilizer input had a significant effect on EEG concentrations in the second growing season. Overall, fertilizer application and crop type had implications for mycorrhizal activity. The soil health status in this study site was deemed low as measured by the impaired mycorrhizal activity due to agricultural management practices. Field inoculation combined with classical and molecular tools could provide a more realistic assessment of the effect of agricultural management practices on AM fungi as potential bioindicators of soil health. Therefore, AM fungi could be used as bioindicators of soil health under agricultural management practices in South African soil conditions.
- Full Text:
Assessing the abundance of non-timber forest products in relation to forest succession on the Wild Coast, South Africa
- Authors: Njwaxu, Afika
- Date: 2019
- Subjects: Non-timber forest products -- South Africa -- Eastern Cape , Forest ecology -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Non-timber forest products -- South Africa -- Willowvale , Forest ecology -- South Africa -- Willowvale , Rural development -- South Africa -- Willowvale , Forest plants -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/94090 , vital:30999
- Description: The number of people in the Eastern Cape, South Africa, that are engaging in arable cropping has declined markedly over the last few decades. This is due to a number of factors such as a decrease in human capital because of migration of able-bodied people to urban areas, disinclination to participate in farming, raiding of crops by livestock and lack of equipment. This has resulted in abandoned croplands being invaded by trees and shrubs as the start of forest succession leading to a change in species composition and the ecosystem benefits reaped from these sites. Key amongst these benefits is a variety of non-timber forests products (NTFPs) which are an integral part of livelihoods in the area. The study was conducted in Willowvale, on the Wild Coast, South Africa. Aerial photographs were used to determine when cessation of cropping occurred in local fields and when revegetation began in order to determine the age of old fields. Botanical inventory and Braun-Blanquet scale were used to assess species richness, composition and abundance of vegetation in fields abandoned at different times. Focus groups were used to identify NTFPs found in these old fields, their uses as well as rank their importance to the local people. Results showed an increase in woody cover with time since field abandonment. Species richness also increased with age of the old field with approximately three species gained per decade. When species richness was disaggregated by growth forms, herbaceous plants were abundant in the early stages of succession, shrubs in the mature stages and trees increased steadily with time. A total of 177 species were recorded from 50 plots that were sampled during the ecological data collection. Of these, 70 species (39.6%) were identified by the focus group participants as NTFPs. The participants grouped the NTFPs into six categories namely: food, building, medicinal, craft, cultural and energy. There was an increase of richness of NTFPs with forest succession; however the proportion of NTFPs decreased with age suggesting an increase in non-useful species. This suggests that harvesting from plots of different ages would be the optimal way for local people to get access to a large variety of NTFPs.
- Full Text:
- Authors: Njwaxu, Afika
- Date: 2019
- Subjects: Non-timber forest products -- South Africa -- Eastern Cape , Forest ecology -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Non-timber forest products -- South Africa -- Willowvale , Forest ecology -- South Africa -- Willowvale , Rural development -- South Africa -- Willowvale , Forest plants -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/94090 , vital:30999
- Description: The number of people in the Eastern Cape, South Africa, that are engaging in arable cropping has declined markedly over the last few decades. This is due to a number of factors such as a decrease in human capital because of migration of able-bodied people to urban areas, disinclination to participate in farming, raiding of crops by livestock and lack of equipment. This has resulted in abandoned croplands being invaded by trees and shrubs as the start of forest succession leading to a change in species composition and the ecosystem benefits reaped from these sites. Key amongst these benefits is a variety of non-timber forests products (NTFPs) which are an integral part of livelihoods in the area. The study was conducted in Willowvale, on the Wild Coast, South Africa. Aerial photographs were used to determine when cessation of cropping occurred in local fields and when revegetation began in order to determine the age of old fields. Botanical inventory and Braun-Blanquet scale were used to assess species richness, composition and abundance of vegetation in fields abandoned at different times. Focus groups were used to identify NTFPs found in these old fields, their uses as well as rank their importance to the local people. Results showed an increase in woody cover with time since field abandonment. Species richness also increased with age of the old field with approximately three species gained per decade. When species richness was disaggregated by growth forms, herbaceous plants were abundant in the early stages of succession, shrubs in the mature stages and trees increased steadily with time. A total of 177 species were recorded from 50 plots that were sampled during the ecological data collection. Of these, 70 species (39.6%) were identified by the focus group participants as NTFPs. The participants grouped the NTFPs into six categories namely: food, building, medicinal, craft, cultural and energy. There was an increase of richness of NTFPs with forest succession; however the proportion of NTFPs decreased with age suggesting an increase in non-useful species. This suggests that harvesting from plots of different ages would be the optimal way for local people to get access to a large variety of NTFPs.
- Full Text:
Assessing the performance of the ‘Aquaculture Operation Phakisa Strategy’ implementation from a stakeholder perspective
- Authors: Halley, Keagan Desmond
- Date: 2019
- Subjects: Marine resources -- Government policy -- South Africa , Fishery management -- South Africa , Aquaculture -- South Africa , Aquaculture industry -- South Africa , Operation Phakisa (South Africa)
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/93867 , vital:30964
- Description: The global demand in aquatic products has seen a number of fisheries depleted worldwide through increase fishing pressure and over exploitation. South Africa in itself has 52 fisheries that are being exploited, of which 48% of these fisheries are of concern, either depleted or heavily depleted. Countries around world have now taken on the responsibility to reduce the reliance on capture fisheries and move towards a more sustainable form of ensuring fish supply. A stabilisation of fisheries stock worldwide has seen the rise of aquaculture as alternative activity that would contribute to reducing pressure on the global fisheries stocks while feeding the demand for fish protein. Aquaculture has since almost equaled the capture based fish supply, contributing to 44.1% of the world’s total fisheries products in 2014 (FAO, 2016). Over the last few years the South African government has focused on developing the aquaculture sector through the development of strategies and policies. The most recent strategy launched in 2014 was Operation Phakisa: Unlocking the Economic Potential of South Africa’s Oceans. The approach of Operation Phakisa looked at accelerating the delivery of government development priorities pertaining to the oceans economy, through development of plans and collaboration of delivery through all stakeholders (public and private stakeholders). Operation Phakisa methodology included bringing key stakeholders within academia, private and public sector, as well as civil society organisations to work together and develop strategies with clear targets that would drive the growth of their specific sectors. The year 2017 marked the midway point of the five year strategy implementation time frame, and an opportunity to assess the performance of the strategy implementation. In order to assess performance of the strategy implementation, the strategy implementation framework developed by Okumus (2003) was identified. Okumus (2003) identifies 11 implementation factors and categorizes these into four categories in the strategy implementation process, based on their role and characteristics, namely: Strategic Content (development of strategy), Strategic Context (internal and external context), Operational Process (operational planning, resource allocation, people, communication, and control) and Outcome (results of implementations process) (Okumus, 2003). The research involved the reviewing of documentation based on the strategy implementation as well as facilitated semi-structure interviews with two stakeholder groups. This was to gain an understanding from the stakeholders’ perspective, on whether the Aquaculture Operation Phakisa Strategy (AOPS) is implemented according to Okumus (2003) Strategy Implementation Framework. Two stakeholder groups were interviewed, namely the officials implementing the strategy, and the aquaculture farmers being affected by the strategy implementation. The research found that eight of out of 11 factors from Okumus (2003) Strategy Implementation Framework were identified as being gaps within the implementation of the AOPS. These gaps were identified across all four main categories for strategy implementation (Strategic content, strategic context, operational process and outcomes). They included; strategy development, organisation structure, organisational culture, leadership, resource allocation, people, communication and outcomes. Furthermore, the researcher found that the perception from the officials differed to that of the aquaculture farmers, with the officials observing a more negative perception towards factors pertaining to organisational structure, organisational culture, leadership, resources allocated, people, communication and outcomes. This negative perception was experience towards the DAFF, Branch Fisheries Management as a whole, rather than within the officials own Chief Directorate (CD:AED), responsible for implementing the strategy. The research assisted with understanding the challenges affecting the implementation of the AOPS as well as unpacked strategy implementation in literature. This aided with developing recommendation to assist with enhancing strategy implementation performance of the AOPS. The following recommendation were provided: Change management within DAFF, Branch Fisheries Management; Identify responsible structures and personnel in DAFF, Branch Fisheries Management; Developing communication platforms within DAFF, Branch Fisheries Management; Review of outcomes of AOPS; and Ensure commitment from all at DAFF, Branch Fisheries Management (leadership). The research paper presents a simple method of assessing the strategy implementation process through the use of a strategy implementation framework.
- Full Text:
- Authors: Halley, Keagan Desmond
- Date: 2019
- Subjects: Marine resources -- Government policy -- South Africa , Fishery management -- South Africa , Aquaculture -- South Africa , Aquaculture industry -- South Africa , Operation Phakisa (South Africa)
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/93867 , vital:30964
- Description: The global demand in aquatic products has seen a number of fisheries depleted worldwide through increase fishing pressure and over exploitation. South Africa in itself has 52 fisheries that are being exploited, of which 48% of these fisheries are of concern, either depleted or heavily depleted. Countries around world have now taken on the responsibility to reduce the reliance on capture fisheries and move towards a more sustainable form of ensuring fish supply. A stabilisation of fisheries stock worldwide has seen the rise of aquaculture as alternative activity that would contribute to reducing pressure on the global fisheries stocks while feeding the demand for fish protein. Aquaculture has since almost equaled the capture based fish supply, contributing to 44.1% of the world’s total fisheries products in 2014 (FAO, 2016). Over the last few years the South African government has focused on developing the aquaculture sector through the development of strategies and policies. The most recent strategy launched in 2014 was Operation Phakisa: Unlocking the Economic Potential of South Africa’s Oceans. The approach of Operation Phakisa looked at accelerating the delivery of government development priorities pertaining to the oceans economy, through development of plans and collaboration of delivery through all stakeholders (public and private stakeholders). Operation Phakisa methodology included bringing key stakeholders within academia, private and public sector, as well as civil society organisations to work together and develop strategies with clear targets that would drive the growth of their specific sectors. The year 2017 marked the midway point of the five year strategy implementation time frame, and an opportunity to assess the performance of the strategy implementation. In order to assess performance of the strategy implementation, the strategy implementation framework developed by Okumus (2003) was identified. Okumus (2003) identifies 11 implementation factors and categorizes these into four categories in the strategy implementation process, based on their role and characteristics, namely: Strategic Content (development of strategy), Strategic Context (internal and external context), Operational Process (operational planning, resource allocation, people, communication, and control) and Outcome (results of implementations process) (Okumus, 2003). The research involved the reviewing of documentation based on the strategy implementation as well as facilitated semi-structure interviews with two stakeholder groups. This was to gain an understanding from the stakeholders’ perspective, on whether the Aquaculture Operation Phakisa Strategy (AOPS) is implemented according to Okumus (2003) Strategy Implementation Framework. Two stakeholder groups were interviewed, namely the officials implementing the strategy, and the aquaculture farmers being affected by the strategy implementation. The research found that eight of out of 11 factors from Okumus (2003) Strategy Implementation Framework were identified as being gaps within the implementation of the AOPS. These gaps were identified across all four main categories for strategy implementation (Strategic content, strategic context, operational process and outcomes). They included; strategy development, organisation structure, organisational culture, leadership, resource allocation, people, communication and outcomes. Furthermore, the researcher found that the perception from the officials differed to that of the aquaculture farmers, with the officials observing a more negative perception towards factors pertaining to organisational structure, organisational culture, leadership, resources allocated, people, communication and outcomes. This negative perception was experience towards the DAFF, Branch Fisheries Management as a whole, rather than within the officials own Chief Directorate (CD:AED), responsible for implementing the strategy. The research assisted with understanding the challenges affecting the implementation of the AOPS as well as unpacked strategy implementation in literature. This aided with developing recommendation to assist with enhancing strategy implementation performance of the AOPS. The following recommendation were provided: Change management within DAFF, Branch Fisheries Management; Identify responsible structures and personnel in DAFF, Branch Fisheries Management; Developing communication platforms within DAFF, Branch Fisheries Management; Review of outcomes of AOPS; and Ensure commitment from all at DAFF, Branch Fisheries Management (leadership). The research paper presents a simple method of assessing the strategy implementation process through the use of a strategy implementation framework.
- Full Text:
Augmentative releases of Dactylopius austrinus De Lotto (Dactylopiidae; Hemiptera) for biological control of Opuntia aurantiaca Lindley (Cactaceae), in South Africa
- Authors: Mulateli, Thifhelimbilu
- Date: 2019
- Subjects: Opuntia aurantiaca -- Biolotical control -- South Africa , Invasive plants -- Biolotical control -- South Africa , Dactylopius austrinus De Lotto -- South Africa , Dactylopius -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92931 , vital:30765
- Description: Opuntia aurantiaca Lindely (Cactaceae) is an invasive alien cactus which has detrimental effects on agroecosystems and indigenous biodiversity in South Africa. Dense infestations over large areas reduce grazing capacity and indigenous biodiversity. Despite the release of a biological control agent, the cochineal insect Dactylopius austrinus De Lotto (Dactylopiidae), the weed is still considered a major problem in many parts of the country. Biological control has relied heavily on classical biological control, with little augmentative biological control implemented. This study investigated the outcome of mass-rearing and augmentative releases of D. austrinus for the control of O. aurantiaca. Augmentative releases are thought to improve the level of control by increasing agent densities in the field and thus increasing the level of damage inflicted to the plants. All data were collected with the intention to optimize release strategies so that the maximum benefit from the biological control agent could be achieved. An impact study was conducted using potted plants in a greenhouse to quantify the efficacy of multiple releases of the agent on the target weed. All three of the release treatments showed consistently higher proportion of cochineal than the controls, as well as the insect exclusion treatments, and these differences were statistically significant. The number of cladodes per plant increased significantly for the insect exclusion and control treatment over the period of the study, whilst all three release treatments decreased steadily over the same period. This study indicated that the agent is damaging to O. aurantiaca and that a single release event was beneficial but that multiple releases did not result in greater levels of control. A post-release evaluation was carried out to quantify the impact of releases of D. austrinus on O. aurantiaca in the field. Plots where the agent was excluded were compared with those where the agent was left at natural field densities and three treatments where agent populations were augmented to varying degrees through releases. The percentage of cochineal infested cladodes for all treatments decreased over time from the initiation of the experiment in October 2017 until the end of the experiment in October 2018. Opuntia aurantiaca densities also decreased over time for all treatments. The insect exclusion treatment had the greatest number of plants for the duration of the study, but this was not significantly different from other treatments. Dactylopius austrinus was damaging to O. aurantiaca, but climatic conditions in the field limited the efficacy of releases. Although O. aurantiaca density decreased during the experiment, it was evident that the reduced number of plants was not due to augmentation of the cochineal populations from the releases that were conducted. The experiment was conducted over a very dry period, when cochineal was particularly effective, so although augmentative releases did not improve the level of control, the natural population of cochineal was high and very damaging to O. aurantiaca over the course of the experiment. Releasing during wet periods, when the agent is less effective, could augment agent populations at a time when natural populations would be low, and hence improve levels of control further. Although this study was limited to a short period of two years, the results of this study suggest that the number of releases is less important than the timing of releases. Releasing immediately after periods of high rainfall is likely to be beneficial, while releasing during dry periods, or during winter when temperatures are low, is less effective. Dactylopius austrinus populations should be constantly monitored so that releases can be conducted when cochineal populations are low and the climatic conditions are correct. If the timing of release events is appropriate, then the over level of control of O. aurantiaca using D. austrinus could be improved.
- Full Text:
- Authors: Mulateli, Thifhelimbilu
- Date: 2019
- Subjects: Opuntia aurantiaca -- Biolotical control -- South Africa , Invasive plants -- Biolotical control -- South Africa , Dactylopius austrinus De Lotto -- South Africa , Dactylopius -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92931 , vital:30765
- Description: Opuntia aurantiaca Lindely (Cactaceae) is an invasive alien cactus which has detrimental effects on agroecosystems and indigenous biodiversity in South Africa. Dense infestations over large areas reduce grazing capacity and indigenous biodiversity. Despite the release of a biological control agent, the cochineal insect Dactylopius austrinus De Lotto (Dactylopiidae), the weed is still considered a major problem in many parts of the country. Biological control has relied heavily on classical biological control, with little augmentative biological control implemented. This study investigated the outcome of mass-rearing and augmentative releases of D. austrinus for the control of O. aurantiaca. Augmentative releases are thought to improve the level of control by increasing agent densities in the field and thus increasing the level of damage inflicted to the plants. All data were collected with the intention to optimize release strategies so that the maximum benefit from the biological control agent could be achieved. An impact study was conducted using potted plants in a greenhouse to quantify the efficacy of multiple releases of the agent on the target weed. All three of the release treatments showed consistently higher proportion of cochineal than the controls, as well as the insect exclusion treatments, and these differences were statistically significant. The number of cladodes per plant increased significantly for the insect exclusion and control treatment over the period of the study, whilst all three release treatments decreased steadily over the same period. This study indicated that the agent is damaging to O. aurantiaca and that a single release event was beneficial but that multiple releases did not result in greater levels of control. A post-release evaluation was carried out to quantify the impact of releases of D. austrinus on O. aurantiaca in the field. Plots where the agent was excluded were compared with those where the agent was left at natural field densities and three treatments where agent populations were augmented to varying degrees through releases. The percentage of cochineal infested cladodes for all treatments decreased over time from the initiation of the experiment in October 2017 until the end of the experiment in October 2018. Opuntia aurantiaca densities also decreased over time for all treatments. The insect exclusion treatment had the greatest number of plants for the duration of the study, but this was not significantly different from other treatments. Dactylopius austrinus was damaging to O. aurantiaca, but climatic conditions in the field limited the efficacy of releases. Although O. aurantiaca density decreased during the experiment, it was evident that the reduced number of plants was not due to augmentation of the cochineal populations from the releases that were conducted. The experiment was conducted over a very dry period, when cochineal was particularly effective, so although augmentative releases did not improve the level of control, the natural population of cochineal was high and very damaging to O. aurantiaca over the course of the experiment. Releasing during wet periods, when the agent is less effective, could augment agent populations at a time when natural populations would be low, and hence improve levels of control further. Although this study was limited to a short period of two years, the results of this study suggest that the number of releases is less important than the timing of releases. Releasing immediately after periods of high rainfall is likely to be beneficial, while releasing during dry periods, or during winter when temperatures are low, is less effective. Dactylopius austrinus populations should be constantly monitored so that releases can be conducted when cochineal populations are low and the climatic conditions are correct. If the timing of release events is appropriate, then the over level of control of O. aurantiaca using D. austrinus could be improved.
- Full Text:
Between drones and al-Shabaab: United States extra-judicial killings in Somalia, sovereignty and the future of liberal intervention
- Authors: Koloko, Mojalefa
- Date: 2019
- Subjects: Somalia -- Politics and government -- 1991- , Somalia -- History -- 1991- , Somalia -- Foreign relations -- United States , Somalia -- Foreign relations -- 1991- , Military assistance, American -- Somalia , Extrajudicial exeutions -- Somalia , Shabaab (Organization)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/67657 , vital:29125
- Description: This study examines the nature of the United States intervention in Somalia, specifically the use of drone strikes that first targeted the militant Sunni Islamist transnational group, al-Qaeda, which claimed responsibility for the 11 September 2001 attacks on the United States, and now target the Somali organisation, Harakat al-Shabaab al-Mujahidin, commonly known as al-Shabaab. The use of drone strikes in the US led war on terror has raised concerns about sovereignty as the extra-judicial killings are conducted without the consent of the concerned states. Furthermore, drone strikes also raise questions about the processes of liberal intervention as the US conducts them without the approval of the United Nations Security Council. It is argued in this study that what is understood to be the “golden era” of liberal interventionism is a legacy of the post-Cold War unipolar dominance of the United States in global governance and security. It is argued that US unipolarity was accompanied by a shifting perception regarding the security position of weak states, whose weakness becomes understood as a source of global insecurity. This perception that so called “weak” and “fragile” states are sources of threats is a departure in International Relations theory, because the discipline is historically preoccupied with studying the actions of powerful states and their consequence for the global order. It is argued that the discourse on the war on terror, and its focus on “failed states” as breeding grounds for alleged terrorists, represents the height of the repositioning of less powerful states from a peripheral status in IR analysis and practice, to their current position that are now being represented as core sources of threat to international peace and security. Through life history interviews with Somali nationals in Grahamstown, Port Elizabeth and Uitenhage, South Africa, the study examines the consequences of US actions from the eyes of Somali people. The findings of this study show that despite all the controversy surrounding the legitimacy of the war on terror, the manner in which it is conducted, as well as the tactics that it employs, the majority of Somali participants showed an overwhelming support for the US intervention. Participants expressed support for the US extra-judicial killings because they are understood to undermine al-Shabaab strength which is a major source of insecurity. The study also shows that the lack of necessary collaboration between the US intelligence and the Somali ground forces has resulted in high numbers of civilian deaths, which participants fear can be used by al-Shabaab to recruit and radicalise more Somalis. The study also shows that most Somalis resent the presence of the African Union Mission in Somalia because Kenya and Ethiopia are seen as 10 pursuing national interests that are not invested in Somali peace and stability. The study concludes that US extra-judicial killings have failed to constrain the actions of al-Shabaab. Somalis expressed that the leadership of current president, Mohamed Abdullahi Mohamed Farmaajo, holds the unique possibilities of creating national unity that rises above clan divisions and the radical Jihadist ideology of al-Shabaab.
- Full Text:
- Authors: Koloko, Mojalefa
- Date: 2019
- Subjects: Somalia -- Politics and government -- 1991- , Somalia -- History -- 1991- , Somalia -- Foreign relations -- United States , Somalia -- Foreign relations -- 1991- , Military assistance, American -- Somalia , Extrajudicial exeutions -- Somalia , Shabaab (Organization)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/67657 , vital:29125
- Description: This study examines the nature of the United States intervention in Somalia, specifically the use of drone strikes that first targeted the militant Sunni Islamist transnational group, al-Qaeda, which claimed responsibility for the 11 September 2001 attacks on the United States, and now target the Somali organisation, Harakat al-Shabaab al-Mujahidin, commonly known as al-Shabaab. The use of drone strikes in the US led war on terror has raised concerns about sovereignty as the extra-judicial killings are conducted without the consent of the concerned states. Furthermore, drone strikes also raise questions about the processes of liberal intervention as the US conducts them without the approval of the United Nations Security Council. It is argued in this study that what is understood to be the “golden era” of liberal interventionism is a legacy of the post-Cold War unipolar dominance of the United States in global governance and security. It is argued that US unipolarity was accompanied by a shifting perception regarding the security position of weak states, whose weakness becomes understood as a source of global insecurity. This perception that so called “weak” and “fragile” states are sources of threats is a departure in International Relations theory, because the discipline is historically preoccupied with studying the actions of powerful states and their consequence for the global order. It is argued that the discourse on the war on terror, and its focus on “failed states” as breeding grounds for alleged terrorists, represents the height of the repositioning of less powerful states from a peripheral status in IR analysis and practice, to their current position that are now being represented as core sources of threat to international peace and security. Through life history interviews with Somali nationals in Grahamstown, Port Elizabeth and Uitenhage, South Africa, the study examines the consequences of US actions from the eyes of Somali people. The findings of this study show that despite all the controversy surrounding the legitimacy of the war on terror, the manner in which it is conducted, as well as the tactics that it employs, the majority of Somali participants showed an overwhelming support for the US intervention. Participants expressed support for the US extra-judicial killings because they are understood to undermine al-Shabaab strength which is a major source of insecurity. The study also shows that the lack of necessary collaboration between the US intelligence and the Somali ground forces has resulted in high numbers of civilian deaths, which participants fear can be used by al-Shabaab to recruit and radicalise more Somalis. The study also shows that most Somalis resent the presence of the African Union Mission in Somalia because Kenya and Ethiopia are seen as 10 pursuing national interests that are not invested in Somali peace and stability. The study concludes that US extra-judicial killings have failed to constrain the actions of al-Shabaab. Somalis expressed that the leadership of current president, Mohamed Abdullahi Mohamed Farmaajo, holds the unique possibilities of creating national unity that rises above clan divisions and the radical Jihadist ideology of al-Shabaab.
- Full Text:
Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1
- Authors: Clarke, Matthew David
- Date: 2019
- Subjects: Mycobacterium avium paratuberculosis , Enzymes -- Biotechnology , Lignocellulose -- Biotechnology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67570 , vital:29112
- Description: Products produced via the enzymatic hydrolysis of lignocellulosic biomass, the most abundant renewable terrestrial source of carbon, can potentially replace a lot of the fuels and chemicals currently produced using non-renewable hydrocarbons. Mannan is a polysaccharide component of lignocellulose that is abundant in softwoods and legume seeds. Enzymatic hydrolysis of mannan by β-mannanases has various industrial applications, including use in biofuel and prebiotic mannooligosaccharide (MOS) production for the improvement of human and animal health. The industrial use of β-mannanases depends on their biochemical characteristics, such as their activity, stability and substrate specificity. Knowledge of their synergistic interactions with other enzymes is also useful for effective hydrolysis. Bacillus paralicheniformis SVD1 was used as a source for β-mannanases. The two mannanases of B. paralicheniformis SVD1 have not been biochemically characterized apart from minor characterization of crude β-mannanase activity. The protein sequences of the two β-mannanases, of glycosyl hydrolase family 5 and 26, have a 95% - 96% identity to the β-mannanases of B. licheniformis DSM13T (=ATCC14580T). These small protein sequence differences could lead to quite different biochemical characteristics. These mannanases were characterized as these enzymes may have industrially useful characteristics. To induce mannanase production, B. paralicheniformis SVD1 was cultured in broth containing the mannan substrate locust bean gum. Various growth curve parameters were measured over 72 h. Mannanase activity was the highest after 48 h of growth - this was the time at which mannanase activity was concentrated, using 3 kDa centrifugal filtration devices, for biochemical characterization of the crude activity. Zymography revealed that the crude concentrated mannanase fraction consisted of at least two mannanases with relative molecular weights (MWs) of 29.6 kDa and 33 kDa. This was smaller than expected – based on their theoretical molecular masses. Protease activity, which was detected in the broth, was probably the reason. There were two pH optima, pH 5.0 and pH 7.0, which also indicated the presence of two mannanases. The concentrated mannanase displayed characteristics that were expected of a B. paralicheniformis β-mannanase. The temperature optimum was 50°C and the activity loss was less than 7% at 50°C after 24 h. Substrate specificity assays revealed that there was predominantly mannanase activity present. Thin layer chromatography (TLC) analysis of mannan and MOS hydrolysis showed that mainly M2 and M3 MOS were produced; only MOS with a degree of polymerization of 4 or higher were hydrolyzed. Hydrolysis was minimal on mannoligosaccharides with galactose substituents. Activity and MOS production was the highest on soluble, low branched mannan substrates. The highest activity observed was on konjac glucomannan. Purification of the mannanase activity was then attempted using various methods. Ammonium sulfate precipitation, acetone precipitation, as well as centrifugal filtration device concentration was assessed for concentration of the mannanase activity.Concentration was not very successful due to low activity yields (≤ 20%). Anion exchange chromatography (AEC) and size exclusion chromatography (SEC) was used for purification. AEC gave good activity yield and fold purification, but SDS-PAGE analysis revealed the presence of many different proteins so further purification was necessary. SDS-PAGE analysis showed that there were only a few protein contaminants in the SEC fraction. However, the yield was too low to allow for biochemical characterization. The optimized purification procedure, which partially purified the mannanase activity, used 85% ammonium sulfate precipitation, followed by AEC. The fold purification was high (88.9) and the specific activity was 29.5 U.mg-1. A zymogram of the partially purified mannanase showed a mannanase active band with a MW of 40 - 41 kDa. A serine protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), was added during the purification steps. This indicated that the mannanase/s in the crude concentrate, without PMSF added, was hydrolyzed by serine protease activity. Native PAGE zymograms suggested that at least two different isoforms of mannanases were present. Additional purification would be required to determine the true characteristics of the mannanase/s. The biochemical characteristics of the crude and partially purified mannanases were similar. The pH optima of the partially purified mannanases were different; the pH optima were 6.0 and 9.0. The substrate specificities were similar, except that the partially purified mannanases displayed no cellulase and β-D-galactosidase activity, but showed a small amount of α-L-arabinase activity. The partially purified mannanase and a Cyamopsis tetragonolobus GH27 α-galactosidase synergistically hydrolyzed locust bean gum. The M50G50 combination displayed the highest extent of hydrolysis; after 24 h there was a 1.39 fold increase in reducing sugar release and the degree of synergy (DS) was 4.64. TLC analysis indicated that synergy increased the release of small MOS. These MOS could be useful as prebiotics. The synergy between the partially purified mannanase and the commercial cellulase mixture Cellic® CTec2 (Novozymes) on spent coffee grounds (SCG) was also determined. SCG is an abundant industrial waste product that has high mannan content. The SCG was pretreated using NaOH, and the monosaccharide, soluble phenolics and insoluble contents were determined. Glucose and mannose were the dominant monosaccharides in the SCG; the pretreated SCG contained 20.4% (w/w) glucose and 18.5% (w/w) mannose, respectively. The NaOH pretreatment improved mannanase hydrolysis of SCG. It resulted in the opening up and swelling of the SCG particles and removed some of the insoluble solids. The partially purified B. paralicheniformis SVD1 mannanase displayed no detectable activity on SCG, but showed synergy with CTec2, in terms of DS, on untreated and NaOH pretreated SCG. This is the first report of mannanasecellulase synergy on SCG; other studies found that increased hydrolysis was due to additive effects. The results obtained in this study are only an initial assessment of the biochemical properties of B. paralicheniformis SVD1 mannanase activity and its synergy with other enzymes. These results can be used to inform future studies.
- Full Text:
- Authors: Clarke, Matthew David
- Date: 2019
- Subjects: Mycobacterium avium paratuberculosis , Enzymes -- Biotechnology , Lignocellulose -- Biotechnology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67570 , vital:29112
- Description: Products produced via the enzymatic hydrolysis of lignocellulosic biomass, the most abundant renewable terrestrial source of carbon, can potentially replace a lot of the fuels and chemicals currently produced using non-renewable hydrocarbons. Mannan is a polysaccharide component of lignocellulose that is abundant in softwoods and legume seeds. Enzymatic hydrolysis of mannan by β-mannanases has various industrial applications, including use in biofuel and prebiotic mannooligosaccharide (MOS) production for the improvement of human and animal health. The industrial use of β-mannanases depends on their biochemical characteristics, such as their activity, stability and substrate specificity. Knowledge of their synergistic interactions with other enzymes is also useful for effective hydrolysis. Bacillus paralicheniformis SVD1 was used as a source for β-mannanases. The two mannanases of B. paralicheniformis SVD1 have not been biochemically characterized apart from minor characterization of crude β-mannanase activity. The protein sequences of the two β-mannanases, of glycosyl hydrolase family 5 and 26, have a 95% - 96% identity to the β-mannanases of B. licheniformis DSM13T (=ATCC14580T). These small protein sequence differences could lead to quite different biochemical characteristics. These mannanases were characterized as these enzymes may have industrially useful characteristics. To induce mannanase production, B. paralicheniformis SVD1 was cultured in broth containing the mannan substrate locust bean gum. Various growth curve parameters were measured over 72 h. Mannanase activity was the highest after 48 h of growth - this was the time at which mannanase activity was concentrated, using 3 kDa centrifugal filtration devices, for biochemical characterization of the crude activity. Zymography revealed that the crude concentrated mannanase fraction consisted of at least two mannanases with relative molecular weights (MWs) of 29.6 kDa and 33 kDa. This was smaller than expected – based on their theoretical molecular masses. Protease activity, which was detected in the broth, was probably the reason. There were two pH optima, pH 5.0 and pH 7.0, which also indicated the presence of two mannanases. The concentrated mannanase displayed characteristics that were expected of a B. paralicheniformis β-mannanase. The temperature optimum was 50°C and the activity loss was less than 7% at 50°C after 24 h. Substrate specificity assays revealed that there was predominantly mannanase activity present. Thin layer chromatography (TLC) analysis of mannan and MOS hydrolysis showed that mainly M2 and M3 MOS were produced; only MOS with a degree of polymerization of 4 or higher were hydrolyzed. Hydrolysis was minimal on mannoligosaccharides with galactose substituents. Activity and MOS production was the highest on soluble, low branched mannan substrates. The highest activity observed was on konjac glucomannan. Purification of the mannanase activity was then attempted using various methods. Ammonium sulfate precipitation, acetone precipitation, as well as centrifugal filtration device concentration was assessed for concentration of the mannanase activity.Concentration was not very successful due to low activity yields (≤ 20%). Anion exchange chromatography (AEC) and size exclusion chromatography (SEC) was used for purification. AEC gave good activity yield and fold purification, but SDS-PAGE analysis revealed the presence of many different proteins so further purification was necessary. SDS-PAGE analysis showed that there were only a few protein contaminants in the SEC fraction. However, the yield was too low to allow for biochemical characterization. The optimized purification procedure, which partially purified the mannanase activity, used 85% ammonium sulfate precipitation, followed by AEC. The fold purification was high (88.9) and the specific activity was 29.5 U.mg-1. A zymogram of the partially purified mannanase showed a mannanase active band with a MW of 40 - 41 kDa. A serine protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), was added during the purification steps. This indicated that the mannanase/s in the crude concentrate, without PMSF added, was hydrolyzed by serine protease activity. Native PAGE zymograms suggested that at least two different isoforms of mannanases were present. Additional purification would be required to determine the true characteristics of the mannanase/s. The biochemical characteristics of the crude and partially purified mannanases were similar. The pH optima of the partially purified mannanases were different; the pH optima were 6.0 and 9.0. The substrate specificities were similar, except that the partially purified mannanases displayed no cellulase and β-D-galactosidase activity, but showed a small amount of α-L-arabinase activity. The partially purified mannanase and a Cyamopsis tetragonolobus GH27 α-galactosidase synergistically hydrolyzed locust bean gum. The M50G50 combination displayed the highest extent of hydrolysis; after 24 h there was a 1.39 fold increase in reducing sugar release and the degree of synergy (DS) was 4.64. TLC analysis indicated that synergy increased the release of small MOS. These MOS could be useful as prebiotics. The synergy between the partially purified mannanase and the commercial cellulase mixture Cellic® CTec2 (Novozymes) on spent coffee grounds (SCG) was also determined. SCG is an abundant industrial waste product that has high mannan content. The SCG was pretreated using NaOH, and the monosaccharide, soluble phenolics and insoluble contents were determined. Glucose and mannose were the dominant monosaccharides in the SCG; the pretreated SCG contained 20.4% (w/w) glucose and 18.5% (w/w) mannose, respectively. The NaOH pretreatment improved mannanase hydrolysis of SCG. It resulted in the opening up and swelling of the SCG particles and removed some of the insoluble solids. The partially purified B. paralicheniformis SVD1 mannanase displayed no detectable activity on SCG, but showed synergy with CTec2, in terms of DS, on untreated and NaOH pretreated SCG. This is the first report of mannanasecellulase synergy on SCG; other studies found that increased hydrolysis was due to additive effects. The results obtained in this study are only an initial assessment of the biochemical properties of B. paralicheniformis SVD1 mannanase activity and its synergy with other enzymes. These results can be used to inform future studies.
- Full Text:
Biological properties and interactions of Kalaharituber pfeilii
- Authors: Krele, Viwe
- Date: 2019
- Subjects: Kalaharituber pfeilii , Pezizales -- South Africa , Desert plants -- South Africa , Truffle culture -- South Africa , Plant biochemical genetics , Enzymes -- Analysis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72257 , vital:30022
- Description: Dessert truffles are seasonal macro fungi and have been identified in several parts of the world including South Africa. The first part of the present study dealt with the assessment of the biologically active compounds of the Kalahari truffles found in the Northern Cape of South Africa. Truffles extracts (methanol, ethanol, aqueous) were investigated for their antimicrobial properties towards Gram-positive and Gram-negative bacteria. The results demonstrated that the truffle extracts tested had no inhibitory effects against the bacterial isolates. The truffle mycelial growth was also noted to be ineffective against the selected bacteria. The bacteria tested in the present study showed some antagonistic effects against the fungus. Cultures of K. pfeilii were also screened for enzyme production including amylase, protease, cellulose, and laccase. Evaluation of the potential of K. pfeilii mycelia to produce these industrially and economically important enzymes demonstrated both amylase and protease activity. However, for laccase and cellulose, no activity was detected. The second part of the present study aimed at optimizing biomass production by K. pfeilii in liquid culture media. FF Microplate containing 95 discreet carbon sources were employed to test for substrate utilization. Blanked readings above 0.1 were regarded as positive for utilization, and 4 substrates were selected as potential substrates and were included in liquid media. Media was evaluated for mycelial biomass production. Of the carbon sources tested sucrose proved to be the most suitable for supporting mycelial growth. The third part of the current study included investigating the diversity of microbial communities colonizing the rhizosheath of Stipagrostis ciliata var. capensis (the host plant of K. pfeilii) and these were identified by means of next-generation sequencing using Illumina Miseq. Bioinformatics tools were utilized in analyzing the data. Actinobacteria were found to be the most dominant bacterial phylum, followed by unclassified bacteria, Proteobacteria, and Acidobacteria. The top 25 sequences were selected and clustered into bacterial OTUs (at 97% threshold) which were assigned into 1 phylum (Actinobacteria), 1 family (Geodermatophilaceae) and 23 genera. This phylum is well known for its secondary metabolites. Streptomyces sp. was the most frequently encountered genus. The results from this study necessitate further investigations with regards to the function and evolution of fungal-bacterial associations. Wheather these bacteria have a contribution towards the truffle development, it is still not confirmed.
- Full Text:
- Authors: Krele, Viwe
- Date: 2019
- Subjects: Kalaharituber pfeilii , Pezizales -- South Africa , Desert plants -- South Africa , Truffle culture -- South Africa , Plant biochemical genetics , Enzymes -- Analysis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/72257 , vital:30022
- Description: Dessert truffles are seasonal macro fungi and have been identified in several parts of the world including South Africa. The first part of the present study dealt with the assessment of the biologically active compounds of the Kalahari truffles found in the Northern Cape of South Africa. Truffles extracts (methanol, ethanol, aqueous) were investigated for their antimicrobial properties towards Gram-positive and Gram-negative bacteria. The results demonstrated that the truffle extracts tested had no inhibitory effects against the bacterial isolates. The truffle mycelial growth was also noted to be ineffective against the selected bacteria. The bacteria tested in the present study showed some antagonistic effects against the fungus. Cultures of K. pfeilii were also screened for enzyme production including amylase, protease, cellulose, and laccase. Evaluation of the potential of K. pfeilii mycelia to produce these industrially and economically important enzymes demonstrated both amylase and protease activity. However, for laccase and cellulose, no activity was detected. The second part of the present study aimed at optimizing biomass production by K. pfeilii in liquid culture media. FF Microplate containing 95 discreet carbon sources were employed to test for substrate utilization. Blanked readings above 0.1 were regarded as positive for utilization, and 4 substrates were selected as potential substrates and were included in liquid media. Media was evaluated for mycelial biomass production. Of the carbon sources tested sucrose proved to be the most suitable for supporting mycelial growth. The third part of the current study included investigating the diversity of microbial communities colonizing the rhizosheath of Stipagrostis ciliata var. capensis (the host plant of K. pfeilii) and these were identified by means of next-generation sequencing using Illumina Miseq. Bioinformatics tools were utilized in analyzing the data. Actinobacteria were found to be the most dominant bacterial phylum, followed by unclassified bacteria, Proteobacteria, and Acidobacteria. The top 25 sequences were selected and clustered into bacterial OTUs (at 97% threshold) which were assigned into 1 phylum (Actinobacteria), 1 family (Geodermatophilaceae) and 23 genera. This phylum is well known for its secondary metabolites. Streptomyces sp. was the most frequently encountered genus. The results from this study necessitate further investigations with regards to the function and evolution of fungal-bacterial associations. Wheather these bacteria have a contribution towards the truffle development, it is still not confirmed.
- Full Text:
Black forest
- Authors: Sachikonye, Tsitsi S A
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92759 , vital:30745
- Full Text:
- Authors: Sachikonye, Tsitsi S A
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/92759 , vital:30745
- Full Text:
BODIPY and porphyrin dyes for direct glucose sensing and optical limiting applications
- Authors: Ndebele, Nobuhle
- Date: 2019
- Subjects: Boron compounds , Boric acid , Porphyrins , Dyes and dying -- Chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97221 , vital:31412
- Description: A series of BODIPY dyes functionalised with boronic acid in the 3,5-positions were successfully synthesised and characterised by using various analytical techniques. The dyes were prepared through a slight modification of the conventional acid catalysed condensation method. Phenylboronic acid moieties were added as styryl groups at the 3,5-positions of the 1,3,5,7-tetrametylBODIPY cores using a modified Knoevengal condensation method. The addition of the styryls resulted in the main absorption band of the dyes red-shifting to the 630−650 nm region. The photophysical and electrochemical properties of these dyes were studied to determine whether the dyes are suitable for use in the fluorescent, colourimetric and electrochemical detection of glucose. Boronic acid moieties were added as bioreceptor recognition elements because they have an affinity for carbohydrates and therefore would be able to bind and “detect” glucose. The series of BODIPY dyes did not show a “turn-on” fluorescence effect upon addition with glucose at the physiological pH. This was attributed on the basis of molecular modelling to the absence of an MO localised on the boronic-acid-substituted styryl moieties that lie close in energy to the HOMO and LUMO that facilitates the formation of an intramolecular charge transfer state. However, colourimetric changes that are visible to the naked eye are observed at basic pH when glucose was added to the dye solutions. The dyes exhibited favourable electrochemical behaviour and were able to detect glucose directly in this context when glassy carbon electrodes are modified through the drop dry method. A series of Sn(IV) porphyrins with thienyl and phenyl groups at the meso-positions were successfully synthesised and characterised. Pyridine and tetrabutyl axial ligands were added to the porphyrins to limit aggregation. The optical limiting properties of these porphyrins and three styrylated BODIPY dyes were studied in benzene and dichloromethane. Dyes were also embedded in polystyrene and studied as thin films to further gauge their suitability for use in optical limiting applications. Second-order hyperpolarizability, third-order susceptibly, non-linear absorption with reversible saturable absorption and the optical limiting threshold, were the parameters studied. Three of the four porphyrins and the three styrylated BODIPY dyes showed favourable optical limiting behaviour, which was further enhanced when the dyes are embedded in polymer thin films.
- Full Text:
- Authors: Ndebele, Nobuhle
- Date: 2019
- Subjects: Boron compounds , Boric acid , Porphyrins , Dyes and dying -- Chemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97221 , vital:31412
- Description: A series of BODIPY dyes functionalised with boronic acid in the 3,5-positions were successfully synthesised and characterised by using various analytical techniques. The dyes were prepared through a slight modification of the conventional acid catalysed condensation method. Phenylboronic acid moieties were added as styryl groups at the 3,5-positions of the 1,3,5,7-tetrametylBODIPY cores using a modified Knoevengal condensation method. The addition of the styryls resulted in the main absorption band of the dyes red-shifting to the 630−650 nm region. The photophysical and electrochemical properties of these dyes were studied to determine whether the dyes are suitable for use in the fluorescent, colourimetric and electrochemical detection of glucose. Boronic acid moieties were added as bioreceptor recognition elements because they have an affinity for carbohydrates and therefore would be able to bind and “detect” glucose. The series of BODIPY dyes did not show a “turn-on” fluorescence effect upon addition with glucose at the physiological pH. This was attributed on the basis of molecular modelling to the absence of an MO localised on the boronic-acid-substituted styryl moieties that lie close in energy to the HOMO and LUMO that facilitates the formation of an intramolecular charge transfer state. However, colourimetric changes that are visible to the naked eye are observed at basic pH when glucose was added to the dye solutions. The dyes exhibited favourable electrochemical behaviour and were able to detect glucose directly in this context when glassy carbon electrodes are modified through the drop dry method. A series of Sn(IV) porphyrins with thienyl and phenyl groups at the meso-positions were successfully synthesised and characterised. Pyridine and tetrabutyl axial ligands were added to the porphyrins to limit aggregation. The optical limiting properties of these porphyrins and three styrylated BODIPY dyes were studied in benzene and dichloromethane. Dyes were also embedded in polystyrene and studied as thin films to further gauge their suitability for use in optical limiting applications. Second-order hyperpolarizability, third-order susceptibly, non-linear absorption with reversible saturable absorption and the optical limiting threshold, were the parameters studied. Three of the four porphyrins and the three styrylated BODIPY dyes showed favourable optical limiting behaviour, which was further enhanced when the dyes are embedded in polymer thin films.
- Full Text:
Careerism and capitalism as women’s emancipation: a critical analysis of Rand Merchant Bank’s ‘Athena Programme', South Africa
- Authors: Mosesi, Poloko Prudence
- Date: 2019
- Subjects: Rand Merchant Bank (South Africa) , Women in economic development -- South Africa , Women in finance -- South Africa , Neoliberalism -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/140344 , vital:37881
- Description: Against the backdrop of debates on feminism and neo– liberalism, this thesis presents a critical analysis of Rand Merchant Bank’s (RMB) Athena programme in South Africa – an award– winning programme run by women, which aims to develop women as senior managers – and of the type of feminism it represents, using a Marxist feminist theoretical framework. Rand Merchant Bank’s is one of the largest investment banks in Africa, part of the giant First Rand Group (FRG) alongside First National Bank (FNB) group. The thesis, based on a detailed case study using qualitative methods, argues that Athena is a very much product of its time: it advances the argument that if more women were in position of power, women in general would be free, and it views the problem of women’s oppression with an individualist lens, which focuses on attitudes and confidence. Athena, like many initiatives of the neo– liberal era, such as Sandberg’s Lean– In philosophy and the Nike Foundation’s ‘Girl Effect’ promote individual understanding and emancipation of women, which sees emancipation in terms of creating a neo– liberal subject that operates more effectively within a capitalist framework, sees capitalism as the solution – rather than the cause – of women’s unequal circumstance and ignores structural issues like class. In effect, Athena argues that the free market and big corporations are neutral tools that can answer the question of women equality, if only women had the correct attitudes, and so long as corporate hierarchies and profits are accepted as fair, and women are seen as an untapped resource that can be used in a ‘smart economics.’ What all these initiatives have in common is shifting the burden and responsibility to women without proper interrogation of the systems that perpetuate inequalities, and a trickle– down theory, according to which more women capitalists and more women in the ruling class will empower the women in the working class.
- Full Text:
- Authors: Mosesi, Poloko Prudence
- Date: 2019
- Subjects: Rand Merchant Bank (South Africa) , Women in economic development -- South Africa , Women in finance -- South Africa , Neoliberalism -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/140344 , vital:37881
- Description: Against the backdrop of debates on feminism and neo– liberalism, this thesis presents a critical analysis of Rand Merchant Bank’s (RMB) Athena programme in South Africa – an award– winning programme run by women, which aims to develop women as senior managers – and of the type of feminism it represents, using a Marxist feminist theoretical framework. Rand Merchant Bank’s is one of the largest investment banks in Africa, part of the giant First Rand Group (FRG) alongside First National Bank (FNB) group. The thesis, based on a detailed case study using qualitative methods, argues that Athena is a very much product of its time: it advances the argument that if more women were in position of power, women in general would be free, and it views the problem of women’s oppression with an individualist lens, which focuses on attitudes and confidence. Athena, like many initiatives of the neo– liberal era, such as Sandberg’s Lean– In philosophy and the Nike Foundation’s ‘Girl Effect’ promote individual understanding and emancipation of women, which sees emancipation in terms of creating a neo– liberal subject that operates more effectively within a capitalist framework, sees capitalism as the solution – rather than the cause – of women’s unequal circumstance and ignores structural issues like class. In effect, Athena argues that the free market and big corporations are neutral tools that can answer the question of women equality, if only women had the correct attitudes, and so long as corporate hierarchies and profits are accepted as fair, and women are seen as an untapped resource that can be used in a ‘smart economics.’ What all these initiatives have in common is shifting the burden and responsibility to women without proper interrogation of the systems that perpetuate inequalities, and a trickle– down theory, according to which more women capitalists and more women in the ruling class will empower the women in the working class.
- Full Text:
Categorising Network Telescope data using big data enrichment techniques
- Authors: Davis, Michael Reginald
- Date: 2019
- Subjects: Denial of service attacks , Big data , Computer networks -- Security measures
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92941 , vital:30766
- Description: Network Telescopes, Internet backbone sampling, IDS and other forms of network-sourced Threat Intelligence provide researchers with insight into the methods and intent of remote entities by capturing network traffic and analysing the resulting data. This analysis and determination of intent is made difficult by the large amounts of potentially malicious traffic, coupled with limited amount of knowledge that can be attributed to the source of the incoming data, as the source is known only by its IP address. Due to the lack of commonly available tooling, many researchers start this analysis from the beginning and so repeat and re-iterate previous research as the bulk of their work. As a result new insight into methods and approaches of analysis is gained at a high cost. Our research approaches this problem by using additional knowledge about the source IP address such as open ports, reverse and forward DNS, BGP routing tables and more, to enhance the researcher's ability to understand the traffic source. The research is a BigData experiment, where large (hundreds of GB) datasets are merged with a two month section of Network Telescope data using a set of Python scripts. The result are written to a Google BigQuery database table. Analysis of the network data is greatly simplified, with questions about the nature of the source, such as its device class (home routing device or server), potential vulnerabilities (open telnet ports or databases) and location becoming relatively easy to answer. Using this approach, researchers can focus on the questions that need answering and efficiently address them. This research could be taken further by using additional data sources such as Geo-location, WHOIS lookups, Threat Intelligence feeds and many others. Other potential areas of research include real-time categorisation of incoming packets, in order to better inform alerting and reporting systems' configuration. In conclusion, categorising Network Telescope data in this way provides insight into the intent of the (apparent) originator and as such is a valuable tool for those seeking to understand the purpose and intent of arriving packets. In particular, the ability to remove packets categorised as non-malicious (e.g. those in the Research category) from the data eliminates a known source of `noise' from the data. This allows the researcher to focus their efforts in a more productive manner.
- Full Text:
- Authors: Davis, Michael Reginald
- Date: 2019
- Subjects: Denial of service attacks , Big data , Computer networks -- Security measures
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92941 , vital:30766
- Description: Network Telescopes, Internet backbone sampling, IDS and other forms of network-sourced Threat Intelligence provide researchers with insight into the methods and intent of remote entities by capturing network traffic and analysing the resulting data. This analysis and determination of intent is made difficult by the large amounts of potentially malicious traffic, coupled with limited amount of knowledge that can be attributed to the source of the incoming data, as the source is known only by its IP address. Due to the lack of commonly available tooling, many researchers start this analysis from the beginning and so repeat and re-iterate previous research as the bulk of their work. As a result new insight into methods and approaches of analysis is gained at a high cost. Our research approaches this problem by using additional knowledge about the source IP address such as open ports, reverse and forward DNS, BGP routing tables and more, to enhance the researcher's ability to understand the traffic source. The research is a BigData experiment, where large (hundreds of GB) datasets are merged with a two month section of Network Telescope data using a set of Python scripts. The result are written to a Google BigQuery database table. Analysis of the network data is greatly simplified, with questions about the nature of the source, such as its device class (home routing device or server), potential vulnerabilities (open telnet ports or databases) and location becoming relatively easy to answer. Using this approach, researchers can focus on the questions that need answering and efficiently address them. This research could be taken further by using additional data sources such as Geo-location, WHOIS lookups, Threat Intelligence feeds and many others. Other potential areas of research include real-time categorisation of incoming packets, in order to better inform alerting and reporting systems' configuration. In conclusion, categorising Network Telescope data in this way provides insight into the intent of the (apparent) originator and as such is a valuable tool for those seeking to understand the purpose and intent of arriving packets. In particular, the ability to remove packets categorised as non-malicious (e.g. those in the Research category) from the data eliminates a known source of `noise' from the data. This allows the researcher to focus their efforts in a more productive manner.
- Full Text:
Changes and continuities over time in the cultural significance of the Nyaminyami water spirit among the BaTonga people of northwestern Zimbabwe
- Authors: Matanzima, Joshua
- Date: 2019
- Subjects: Water spirits -- Zimbabwe , Tsonga (African people) -- Zimbabwe , Tsonga (African people) -- Zimbabwe -- Religion , Tsonga (African people) -- Zimbabwe -- Rites and ceremonies , Tsonga (African people) -- Zimbabwe -- Social life and customs , Mythology, Tsonga , Mythology, Zimbabwean , Nyaminyami (Spirit)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/94189 , vital:31015
- Description: Research attests that beliefs in water spirits are an integral part of cultures of many indigenous communities across the globe. These water spirits play significant political, religious and socio-economic roles for the people concerned. However, the functions of water spirits are not constant, but change over time, especially when the people believing in water spirits undergo drastic socio- economic processes of change. It is in this context that this thesis traces the cultural significance over time, of the Nyaminyami water spirit, among some BaTonga people, living in the immediate vicinity of the Kariba gorge area, in north-western Zimbabwe. While previous studies document the existence of beliefs in Nyaminyami, none of these has systematically traced the historical significance of Nyaminyami, in terms of changes and continuities over time. Thus, this thesis makes a valuable contribution to knowledge with regards to the history and religion of the BaTonga people. The thesis argues that Nyaminyami‘s cultural significance or functions evolved over time, due to numerous socio- economic and political processes of change. The major changes that significantly influenced the practices relating to Nyaminyami include colonialism, Kariba dam construction and resettlement, the migration after resettlement in the 1960s and 1970s, the independence of Zimbabwe, and the alienation of the Kariba waterscape from the BaTonga. To be able to arrive at specific findings and conclusions, the thesis is underpinned by theories about resettlement, approaches to water divinities, and theories of religion and social change. The thesis has five ethnographic chapters that focus on specific time periods, illustrating the major socio- economic changes of each epoch, and showing how these changes impacted upon practices and beliefs relating to Nyaminyami. The thesis also documents how Nyaminyami beliefs are variedly distributed along different social variables that include gender, age, income and geographical location. In order to achieve the findings presented, the thesis utilized ethnographic evidence obtained from semi- structured interviews, participant observation, anthropology of extraordinary experience, document review and archival research.
- Full Text:
- Authors: Matanzima, Joshua
- Date: 2019
- Subjects: Water spirits -- Zimbabwe , Tsonga (African people) -- Zimbabwe , Tsonga (African people) -- Zimbabwe -- Religion , Tsonga (African people) -- Zimbabwe -- Rites and ceremonies , Tsonga (African people) -- Zimbabwe -- Social life and customs , Mythology, Tsonga , Mythology, Zimbabwean , Nyaminyami (Spirit)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/94189 , vital:31015
- Description: Research attests that beliefs in water spirits are an integral part of cultures of many indigenous communities across the globe. These water spirits play significant political, religious and socio-economic roles for the people concerned. However, the functions of water spirits are not constant, but change over time, especially when the people believing in water spirits undergo drastic socio- economic processes of change. It is in this context that this thesis traces the cultural significance over time, of the Nyaminyami water spirit, among some BaTonga people, living in the immediate vicinity of the Kariba gorge area, in north-western Zimbabwe. While previous studies document the existence of beliefs in Nyaminyami, none of these has systematically traced the historical significance of Nyaminyami, in terms of changes and continuities over time. Thus, this thesis makes a valuable contribution to knowledge with regards to the history and religion of the BaTonga people. The thesis argues that Nyaminyami‘s cultural significance or functions evolved over time, due to numerous socio- economic and political processes of change. The major changes that significantly influenced the practices relating to Nyaminyami include colonialism, Kariba dam construction and resettlement, the migration after resettlement in the 1960s and 1970s, the independence of Zimbabwe, and the alienation of the Kariba waterscape from the BaTonga. To be able to arrive at specific findings and conclusions, the thesis is underpinned by theories about resettlement, approaches to water divinities, and theories of religion and social change. The thesis has five ethnographic chapters that focus on specific time periods, illustrating the major socio- economic changes of each epoch, and showing how these changes impacted upon practices and beliefs relating to Nyaminyami. The thesis also documents how Nyaminyami beliefs are variedly distributed along different social variables that include gender, age, income and geographical location. In order to achieve the findings presented, the thesis utilized ethnographic evidence obtained from semi- structured interviews, participant observation, anthropology of extraordinary experience, document review and archival research.
- Full Text:
Chitin hydrolysis with chitinolytic enzymes for the production of chitooligomers with antimicrobial properties
- Authors: Oree, Glynis
- Date: 2019
- Subjects: Chitin -- Biotechnology , Enzymes -- Biotechnology , Hydrolysis , Chitooligomers -- Biotechnology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67887 , vital:29165
- Description: There are many diseases and illnesses in the world that require new drug treatments and chitin has been shown to produce chitooligomeric derivatives which exhibit promising antimicrobial and immune-enhancing properties. However, the rate-limiting step is associated with the high recalcitrance of chitinous substrates, and low hydrolytic activities of chitinolytic enzymes, resulting in low product release. To improve and create a more sustainable and economical process, enhancing chitin hydrolysis through various treatment procedures is essential for obtaining high enzyme hydrolysis rates, resulting in a higher yield of chitooligomers (CHOS). In literature, pre-treatment of insoluble biomass is generally associated with an increase in accessibility of the carbohydrate to hydrolytic enzymes, thus generating more products. The first part of this study investigated the effect of alkali- (NaOH) and acid pre-treatments (HCl and phosphoric acid) on chitin biomass, and chemical and morphological modifications were assessed by the employment of scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy-Dispersive X-ray spectrometery (EDX) and x-ray diffraction (XRD). Data obtained confirmed that pre-treated substrates were more chemically and morphologically modified. These results confirmed the fact that pre-treatment of chitin disrupts the structure of the biomass, rendering the polymer more accessible for enzymatic hydrolysis. The commercial chitinases from Bacillus cereus and Streptomyces griseus (CHB and CHS) are costly. Bio-prospecting for other chitin-degrading enzymes from alternate sources such as Oidiodendron maius, or the recombinant expression of CHOS, was a more economically feasible avenue. The chit1 gene from Thermomyces lanuginosus, expressed in Pichia pastoris, produced a large range CHOS with a degree of polymerisation (DP) ranging from 1 to above 6. TLC analysis showed that O. maius exhibited chitin-degrading properties by producing CHOS with a DP length of 1 to 3. These two sources were therefore successful in producing chitin-degrading enzymes. The physico-chemical properties of commercial (CHB and CHS) and expressed (Chit1) chitinolytic enzymes were investigated, to determine under which biochemical conditions and on which type of biomass they can function on optimally, for the production of value-added products such as CHOS. Substrate affinity assays were conducted on the un-treated and pre-treated biomass. TLC revealed that chitosan hydrolysis by the commercial chitinases produced the largest range of CHOS with a DP length ranging from 1 to 6. A range of temperatures (35-90oC) were investigated and CHB, CHS and Chit1 displayed optimum activities at 50, 40 and 45 oC, respectively. Thermostability studies that were conducted at 37 and 50oC revealed that CHB and CHS were most stable at 37oC. Chit1 showed great thermostablity at both temperatures, rendering this enzyme suitable for industrial processes at high temperatures. pH optima studies demonstrated that the pH optima for CHB, CHS and Chit1 was at a pH of 5.0, with specific activities of 33.459, 46.2 and 5.776 μmol/h/mg, respectively. The chain cleaving patterns of the commercial enzymes were determined and exo-chitinase activity was exhibited, due to the production of CHOS that were predominantly of a DP length of 2. Enzyme binary synergy studies were conducted with commercial chitinases (CHB and CHS) on colloidal chitin. Studies illustrated that the simultaneous combination of CHB 75%: CHS 25% produced the highest specific activity (3.526 μmol/h/mg), with no synergy. TLC analysis of this enzyme combination over time revealed that predominantly chitobiose was produced. This suggested that the substrate crystallinity and morphology played an important role in the way the enzymes cleaved the carbohydrate. Since CHOS have shown great promise for their antimicrobial properties, the CHOS generated from the chitinous substrates were tested for antimicrobial properties on Bacillus subtilis, Escherichia coli, Klebsiella and Staphlococcus aureus. This study revealed that certain CHOS produced have inhibitory effects on certain bacteria and could potentially be used in the pharamceutical or medical industries. In conclusion, this study revealed that chitinases can be produced and found in alternate sources and be used for the hydrolysis of chitinous biomass in a more sustainabe and economically viable manner. The chitinases investigated (CHB, CHS and Chit1) exhibited different cleaving patterns of the chitinous substrates due to the chemical and morphological properties of the biomass. CHOS produced from chitinous biomass exhibited some inhibitory effects on bacterial growth and show potential for use in the medical industry.
- Full Text:
- Authors: Oree, Glynis
- Date: 2019
- Subjects: Chitin -- Biotechnology , Enzymes -- Biotechnology , Hydrolysis , Chitooligomers -- Biotechnology
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67887 , vital:29165
- Description: There are many diseases and illnesses in the world that require new drug treatments and chitin has been shown to produce chitooligomeric derivatives which exhibit promising antimicrobial and immune-enhancing properties. However, the rate-limiting step is associated with the high recalcitrance of chitinous substrates, and low hydrolytic activities of chitinolytic enzymes, resulting in low product release. To improve and create a more sustainable and economical process, enhancing chitin hydrolysis through various treatment procedures is essential for obtaining high enzyme hydrolysis rates, resulting in a higher yield of chitooligomers (CHOS). In literature, pre-treatment of insoluble biomass is generally associated with an increase in accessibility of the carbohydrate to hydrolytic enzymes, thus generating more products. The first part of this study investigated the effect of alkali- (NaOH) and acid pre-treatments (HCl and phosphoric acid) on chitin biomass, and chemical and morphological modifications were assessed by the employment of scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy-Dispersive X-ray spectrometery (EDX) and x-ray diffraction (XRD). Data obtained confirmed that pre-treated substrates were more chemically and morphologically modified. These results confirmed the fact that pre-treatment of chitin disrupts the structure of the biomass, rendering the polymer more accessible for enzymatic hydrolysis. The commercial chitinases from Bacillus cereus and Streptomyces griseus (CHB and CHS) are costly. Bio-prospecting for other chitin-degrading enzymes from alternate sources such as Oidiodendron maius, or the recombinant expression of CHOS, was a more economically feasible avenue. The chit1 gene from Thermomyces lanuginosus, expressed in Pichia pastoris, produced a large range CHOS with a degree of polymerisation (DP) ranging from 1 to above 6. TLC analysis showed that O. maius exhibited chitin-degrading properties by producing CHOS with a DP length of 1 to 3. These two sources were therefore successful in producing chitin-degrading enzymes. The physico-chemical properties of commercial (CHB and CHS) and expressed (Chit1) chitinolytic enzymes were investigated, to determine under which biochemical conditions and on which type of biomass they can function on optimally, for the production of value-added products such as CHOS. Substrate affinity assays were conducted on the un-treated and pre-treated biomass. TLC revealed that chitosan hydrolysis by the commercial chitinases produced the largest range of CHOS with a DP length ranging from 1 to 6. A range of temperatures (35-90oC) were investigated and CHB, CHS and Chit1 displayed optimum activities at 50, 40 and 45 oC, respectively. Thermostability studies that were conducted at 37 and 50oC revealed that CHB and CHS were most stable at 37oC. Chit1 showed great thermostablity at both temperatures, rendering this enzyme suitable for industrial processes at high temperatures. pH optima studies demonstrated that the pH optima for CHB, CHS and Chit1 was at a pH of 5.0, with specific activities of 33.459, 46.2 and 5.776 μmol/h/mg, respectively. The chain cleaving patterns of the commercial enzymes were determined and exo-chitinase activity was exhibited, due to the production of CHOS that were predominantly of a DP length of 2. Enzyme binary synergy studies were conducted with commercial chitinases (CHB and CHS) on colloidal chitin. Studies illustrated that the simultaneous combination of CHB 75%: CHS 25% produced the highest specific activity (3.526 μmol/h/mg), with no synergy. TLC analysis of this enzyme combination over time revealed that predominantly chitobiose was produced. This suggested that the substrate crystallinity and morphology played an important role in the way the enzymes cleaved the carbohydrate. Since CHOS have shown great promise for their antimicrobial properties, the CHOS generated from the chitinous substrates were tested for antimicrobial properties on Bacillus subtilis, Escherichia coli, Klebsiella and Staphlococcus aureus. This study revealed that certain CHOS produced have inhibitory effects on certain bacteria and could potentially be used in the pharamceutical or medical industries. In conclusion, this study revealed that chitinases can be produced and found in alternate sources and be used for the hydrolysis of chitinous biomass in a more sustainabe and economically viable manner. The chitinases investigated (CHB, CHS and Chit1) exhibited different cleaving patterns of the chitinous substrates due to the chemical and morphological properties of the biomass. CHOS produced from chitinous biomass exhibited some inhibitory effects on bacterial growth and show potential for use in the medical industry.
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Climatic suitability of Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), a shoot-boring moth for the biological control of Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae) in South Africa
- Authors: Nqayi, Slindile Brightness
- Date: 2019
- Subjects: CLIMEX , Chromolaena odorata -- Biological control -- South Africa , Tortricidae -- South Africa , Bioclimatology -- Software
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92208 , vital:30681
- Description: Biological control using natural enemies introduced from the native range is an integral component of the management of Chromolaena odorata, a serious invader in the eastern regions of South Africa. A number of biological control agents for C. odorata have been released in South Africa, and one of them, Dichrorampha odorata, has failed to establish. To understand if D. odorata failed to establish due to climate incompatibility, its thermal physiology was investigated. Thermal tolerance data were used to determine the developmental thresholds and number of generations that D. odorata is capable of going through in South Africa per year. These predictions were generated using CLIMEX temperature data and the degree-day parameters K and t0. Developmental time decreased with increasing temperatures ranging from 20 °C to 30°C, with immature stages not able to complete development at 18°C and 32°C. The developmental threshold, to, was determined as 8.45 °C with 872.4 degree-days required to complete development (K), indicating that D. odorata is capable of producing a maximum number of 6.5 generations per year in South Africa. The CLIMEX data indicated that the east coast regions of South Africa, which are the heaviest invaded areas by C. odorata in South Africa, were climatically most suitable for D. odorata to. D. odorata lower (LLT50) and upper (ULT50) lethal temperatures were -4.5°C and 39.64°C for larvae and 1.83 and 41.02°C for adults, and D. odorata adults were able to maintain locomotory functioning at 4.4 to 43.7°C, respectively. Acclimation at low and high temperatures indicate that when D. odorata was kept at a lower temperature of 20°C for 7 days, it became tolerant to warmer and cooler temperatures (1.95 and 44.41°C) when compared to D. odorata reared at 25°C (3.36 and 43.67°C) and 30°C (5.92 and 42.93°C). Dichrorampha odorata is therefore climatically suitable for release and should establish in South Africa to control C. odorata. The establishment and persistence of D. odorata will not be limited by climatic conditions but rather the distribution of its host weed, C. odorata in South Africa. Also, this study presents a decision-making protocol for the release of D. odorata to allow better performance in the field.
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- Authors: Nqayi, Slindile Brightness
- Date: 2019
- Subjects: CLIMEX , Chromolaena odorata -- Biological control -- South Africa , Tortricidae -- South Africa , Bioclimatology -- Software
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/92208 , vital:30681
- Description: Biological control using natural enemies introduced from the native range is an integral component of the management of Chromolaena odorata, a serious invader in the eastern regions of South Africa. A number of biological control agents for C. odorata have been released in South Africa, and one of them, Dichrorampha odorata, has failed to establish. To understand if D. odorata failed to establish due to climate incompatibility, its thermal physiology was investigated. Thermal tolerance data were used to determine the developmental thresholds and number of generations that D. odorata is capable of going through in South Africa per year. These predictions were generated using CLIMEX temperature data and the degree-day parameters K and t0. Developmental time decreased with increasing temperatures ranging from 20 °C to 30°C, with immature stages not able to complete development at 18°C and 32°C. The developmental threshold, to, was determined as 8.45 °C with 872.4 degree-days required to complete development (K), indicating that D. odorata is capable of producing a maximum number of 6.5 generations per year in South Africa. The CLIMEX data indicated that the east coast regions of South Africa, which are the heaviest invaded areas by C. odorata in South Africa, were climatically most suitable for D. odorata to. D. odorata lower (LLT50) and upper (ULT50) lethal temperatures were -4.5°C and 39.64°C for larvae and 1.83 and 41.02°C for adults, and D. odorata adults were able to maintain locomotory functioning at 4.4 to 43.7°C, respectively. Acclimation at low and high temperatures indicate that when D. odorata was kept at a lower temperature of 20°C for 7 days, it became tolerant to warmer and cooler temperatures (1.95 and 44.41°C) when compared to D. odorata reared at 25°C (3.36 and 43.67°C) and 30°C (5.92 and 42.93°C). Dichrorampha odorata is therefore climatically suitable for release and should establish in South Africa to control C. odorata. The establishment and persistence of D. odorata will not be limited by climatic conditions but rather the distribution of its host weed, C. odorata in South Africa. Also, this study presents a decision-making protocol for the release of D. odorata to allow better performance in the field.
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Clinical psychologists’ perceptions of the phenomenon of schizophrenia in a psychiatric setting in the Eastern Cape, South Africa
- Authors: Hamman, Colette
- Date: 2019
- Subjects: Schizophrenia -- Diagnosis -- South Africa , Schizophrenia -- Treatment -- South Africa , Schizophrenics -- Rehabilitation -- South Africa , Schizophrenics -- South Africa -- Case studies
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/71398 , vital:29845
- Description: Numerous international and South African scholars are critical of the dominant research on the phenomenon of schizophrenia. Rather than refuting dominant biomedical psychiatric conceptualisations of schizophrenia, there is a call for incorporating a focus on the psychology of the person diagnosed with schizophrenia. In South Africa, the integration of the psychosocial components of psychotic experiences into the understanding and treatment of psychosis are still neglected in biomedically-focused psychiatric settings. In relation to this call, the role of clinical psychologists working within these settings seems pertinent. Against this background, this study aimed to explore and describe the perceptions of clinical psychologists, working in a psychiatric setting in South Africa, in relation to the phenomenon of schizophrenia. Informed by a social constructionist theoretical framework, this study utilised a qualitative research design and a semi-structured interview schedule. In-depth, individual interviews were conducted with three clinical psychologists and the transcribed interviews were analysed using thematic analysis. From the data, perceptions were identified as largely polarised in relation to the phenomenon of schizophrenia. These polarised perceptions included: Physical impact of schizophrenia versus social impact of schizophrenia; rehabilitation of schizophrenia versus recovery within schizophrenia; diagnostic frameworks as useful versus diagnostic frameworks as limiting; and institutionally-defined identity versus self-defined identity. In terms of these polarised perceptions, an overarching theme of the medicalisation versus the demedicalisation of schizophrenia was identified. Therefore, the perceptions of clinical psychologists in this study were largely polarised towards either a medicalisation of the phenomenon of schizophrenia or a demedicalisation of it. However, perceptions were also identified that evidenced an integration of the two sides of the polarities, and a holding of tension between seemingly incompatible or incongruent frameworks. The participants perceived psychologists as positioned in the middle ground between the medicalisation and demedicalisation of schizophrenia in a biomedical psychiatric setting. In response to the call for a focus on the psychology of the person diagnosed with schizophrenia, the findings support both the value and the need for an “integration of polarised perceptions”, “holding of the tension”, and “middle ground positioning” of clinicians between medicalised and demedicalised aspects of the phenomenon of schizophrenia.
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- Authors: Hamman, Colette
- Date: 2019
- Subjects: Schizophrenia -- Diagnosis -- South Africa , Schizophrenia -- Treatment -- South Africa , Schizophrenics -- Rehabilitation -- South Africa , Schizophrenics -- South Africa -- Case studies
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/71398 , vital:29845
- Description: Numerous international and South African scholars are critical of the dominant research on the phenomenon of schizophrenia. Rather than refuting dominant biomedical psychiatric conceptualisations of schizophrenia, there is a call for incorporating a focus on the psychology of the person diagnosed with schizophrenia. In South Africa, the integration of the psychosocial components of psychotic experiences into the understanding and treatment of psychosis are still neglected in biomedically-focused psychiatric settings. In relation to this call, the role of clinical psychologists working within these settings seems pertinent. Against this background, this study aimed to explore and describe the perceptions of clinical psychologists, working in a psychiatric setting in South Africa, in relation to the phenomenon of schizophrenia. Informed by a social constructionist theoretical framework, this study utilised a qualitative research design and a semi-structured interview schedule. In-depth, individual interviews were conducted with three clinical psychologists and the transcribed interviews were analysed using thematic analysis. From the data, perceptions were identified as largely polarised in relation to the phenomenon of schizophrenia. These polarised perceptions included: Physical impact of schizophrenia versus social impact of schizophrenia; rehabilitation of schizophrenia versus recovery within schizophrenia; diagnostic frameworks as useful versus diagnostic frameworks as limiting; and institutionally-defined identity versus self-defined identity. In terms of these polarised perceptions, an overarching theme of the medicalisation versus the demedicalisation of schizophrenia was identified. Therefore, the perceptions of clinical psychologists in this study were largely polarised towards either a medicalisation of the phenomenon of schizophrenia or a demedicalisation of it. However, perceptions were also identified that evidenced an integration of the two sides of the polarities, and a holding of tension between seemingly incompatible or incongruent frameworks. The participants perceived psychologists as positioned in the middle ground between the medicalisation and demedicalisation of schizophrenia in a biomedical psychiatric setting. In response to the call for a focus on the psychology of the person diagnosed with schizophrenia, the findings support both the value and the need for an “integration of polarised perceptions”, “holding of the tension”, and “middle ground positioning” of clinicians between medicalised and demedicalised aspects of the phenomenon of schizophrenia.
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