Photophysico-chemical properties and photoinactivation of Staphylococcus Aureus using zinc phthalocyanines linked silver nanoparticles conjugates
- Matlou, Gauta G, Nyokong, Tebello
- Authors: Matlou, Gauta G , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186278 , vital:44481 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108237"
- Description: The synthesis of zinc (II) tri (tert-butyl phenoxy) mono cinnamic acid Pc (complex 1) is reported for the first time in this work. Complex 1 and the reported zinc (II) tri (tert-butyl), mono cinnamic acid phthalocyanine (2), zinc (II) mono cinnamic acid substituted phthalocyanine (3) and zinc (II) tetra cinnamic acid substituted phthalocyanine (4) are conjugated to cysteine capped silver nanoparticles (cys-AgNPs) through an amide bond. The photophysicochemical properties and the photodynamic antimicrobial chemotherapy (PACT) activities of the Pc-cys-AgNPs conjugates and the Pcs alone on S. Aureus are reported. Improved triplet and singlet oxygen quantum yields were observed for the conjugated complexes compared to Pcs alone, due to the heavy atom effect of cys-AgNPs. Asymmetric complexes 1,2, 3 and their respective conjugates recorded higher photosensitizing properties and PACT activities compared to 4 and 4-cys-AgNPs, respectively. Higher log reductions and percentage reductions of S. Aureus were recorded for conjugated complexes compared to ZnPcs only, showing enhanced PACT activities due to their higher singlet oxygen quantum yields.
- Full Text:
- Authors: Matlou, Gauta G , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186278 , vital:44481 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108237"
- Description: The synthesis of zinc (II) tri (tert-butyl phenoxy) mono cinnamic acid Pc (complex 1) is reported for the first time in this work. Complex 1 and the reported zinc (II) tri (tert-butyl), mono cinnamic acid phthalocyanine (2), zinc (II) mono cinnamic acid substituted phthalocyanine (3) and zinc (II) tetra cinnamic acid substituted phthalocyanine (4) are conjugated to cysteine capped silver nanoparticles (cys-AgNPs) through an amide bond. The photophysicochemical properties and the photodynamic antimicrobial chemotherapy (PACT) activities of the Pc-cys-AgNPs conjugates and the Pcs alone on S. Aureus are reported. Improved triplet and singlet oxygen quantum yields were observed for the conjugated complexes compared to Pcs alone, due to the heavy atom effect of cys-AgNPs. Asymmetric complexes 1,2, 3 and their respective conjugates recorded higher photosensitizing properties and PACT activities compared to 4 and 4-cys-AgNPs, respectively. Higher log reductions and percentage reductions of S. Aureus were recorded for conjugated complexes compared to ZnPcs only, showing enhanced PACT activities due to their higher singlet oxygen quantum yields.
- Full Text:
Production, purification and characterization of a multifunctional, thermostable and acido/alkaline stable putative xylanase from the psychrotrophic bacterium, Sphingomonas aerolata
- Authors: Mathibe, Brian Nkanyiso
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164478 , vital:41122
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Authors: Mathibe, Brian Nkanyiso
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164478 , vital:41122
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
Creative Cities and Regional Development: The Case of Makhanda and the Creative City Project
- Authors: Campbell, Guy John
- Date: 2021
- Subjects: To be assigned
- Language: English
- Type: thesis , text , Masters , MCOM
- Identifier: http://hdl.handle.net/10962/174448 , vital:42478
- Description: Thesis (MSc)--Rhodes University, Faculty of Commerce, Economics and Economic History, 2020
- Full Text:
- Authors: Campbell, Guy John
- Date: 2021
- Subjects: To be assigned
- Language: English
- Type: thesis , text , Masters , MCOM
- Identifier: http://hdl.handle.net/10962/174448 , vital:42478
- Description: Thesis (MSc)--Rhodes University, Faculty of Commerce, Economics and Economic History, 2020
- Full Text:
The relative suitability of knowledge paradigms to indigenous African resource management and their implications for environmental bioethics, environmental policy and food security
- Authors: Agbor Ambang, Oscar Mbi
- Date: 2020-04
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , M.Pharm
- Identifier: http://hdl.handle.net/10962/163091 , vital:41011
- Description: Thesis (M.Pharm)--Rhodes University, Faculty of Pharmacy, Pharmacy, 2020.
- Full Text:
- Authors: Agbor Ambang, Oscar Mbi
- Date: 2020-04
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , M.Pharm
- Identifier: http://hdl.handle.net/10962/163091 , vital:41011
- Description: Thesis (M.Pharm)--Rhodes University, Faculty of Pharmacy, Pharmacy, 2020.
- Full Text:
Exploring the structural integrity of a picornavirus capsid
- Authors: Upfold, Nicole Sarah
- Date: 2020
- Subjects: Picornaviruses , Immunoglobulins , Capsids (Virology) , Viruses Morphology , RNA viruses
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/131837 , vital:36758 , DOI https://doi.org/10.21504/10962/131837
- Description: Picornaviruses are a diverse family of small RNA viruses that cause a broad range of human and veterinary diseases. Despite decades of research into the molecular biology of these pathogens, no antivirals and few vaccines are commercially available for the treatment and prevention of picornavirus infections. The capsids of these non-enveloped viruses are involved in many important aspects of the picornavirus lifecycle, such as cell attachment and entry, uncoating, and protection of the viral RNA. Although the structures of many picornavirus capsids have been solved, a broader understanding of the molecular determinants that are required for structural integrity and stability is imperative for an improved understanding of the basic biology of these viruses, and for designing effective control strategies. Collectively, this thesis aims to elucidate the molecular determinants of structural stability and integrity in the Theiler’s murine encephalomyelitis virus capsid (TMEV). To study the TMEV GDVII capsid using biochemical techniques, neutralising polyclonal antibodies were generated against GDVII particles. The antibodies recognised linear epitopes in the C-terminus of the VP1 protein, but not those present in VP2 or VP3. The VP1 C-terminal residues were mapped to a loop above the putative receptor binding pit on the capsid surface, which prompted an investigation into the potential binding site of the TMEV co-receptor, heparan sulphate. Molecular docking revealed that heparan interacts with residues of the receptor binding pocket, as well as residues of the adjoining VP1 C-terminal loop. These findings suggest that the antibodies neutralise virus infection by preventing attachment of the virus to the co-receptor and possibly the unknown primary receptor. Few studies have identified the specific residues and interactions at subunit interfaces that significantly contribute to picornavirus capsid stability, assembly, and function. A novel in-silico screen was developed for the prediction of hotspot residues at protein-protein interfaces of a virus capsid. This screen can be applied to elucidate the residues that contribute significantly to the intraprotomer, interprotomer and interpentamer interfaces of any picornavirus capsid, on condition that the structure of the virus is available. The screen was applied to TMEV GDVII resulting in the identification of hotspots, several of which correspond to residues that are known to be important for aspects of the virus lifecycle, such as those that contribute to pH stability or form part of receptor binding sites. This observation suggests that residues involved in specific capsid functions may also play a role in capsid stability. Many of the residues identified as hotspots in TMEV corresponded to those required for assembly, uncoating, and virus growth in representative picornaviruses from various genera, suggesting that the residues that regulate capsid stability may be somewhat conserved across the family. Hotspots identified at the interpentamer interfaces of TMEV were individually substituted to alanine to further explore their importance to the TMEV lifecycle. All the amino acid substitutions prevented completion of the virus lifecycle as no CPE was observed following transfection of susceptible cells. Immunofluorescence experiments demonstrated that virus protein synthesis and RNA replication were not inhibited by substitution of the hotspot residues, but that infectivity was severely impeded. This confirmed that the residues were required for some aspect of the virus lifecycle, such as capsid assembly, or were critical for maintaining the conformational stability of the TMEV particles. Virus capsids become unstable and are prone to dissociation under certain conditions such as extreme pH and non-physiological temperatures. The thermostability of TMEV was explored by selecting GDVII virions with improved thermal tolerance through serial passage and heat exposure. Thermostable virions that could tolerate temperatures above 57 °C had reduced infective titres compared to the wild type TMEV suggesting that the virus adapted to thermal stress at the expense of viral fitness. Sequencing the capsid encoding regions of the mutant virions revealed a pair of amino acid substitutions that were present in all mutants. Additional substitutions that were unique to viruses selected at different temperatures were also identified. Most of the substitutions were located within the intraprotomer interfaces of the virus, unlike previous studies on enteroviruses where mutations were mostly localised to the receptor binding pocket. This thesis provides the first analysis of the structural determinants of TMEV capsid stability. The generation of tools to further explore the capsid structures of TMEV and other picornaviruses provides an opportunity for future studies which may contribute to the development of novel control strategies against this important family of viruses. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text: false
- Authors: Upfold, Nicole Sarah
- Date: 2020
- Subjects: Picornaviruses , Immunoglobulins , Capsids (Virology) , Viruses Morphology , RNA viruses
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/131837 , vital:36758 , DOI https://doi.org/10.21504/10962/131837
- Description: Picornaviruses are a diverse family of small RNA viruses that cause a broad range of human and veterinary diseases. Despite decades of research into the molecular biology of these pathogens, no antivirals and few vaccines are commercially available for the treatment and prevention of picornavirus infections. The capsids of these non-enveloped viruses are involved in many important aspects of the picornavirus lifecycle, such as cell attachment and entry, uncoating, and protection of the viral RNA. Although the structures of many picornavirus capsids have been solved, a broader understanding of the molecular determinants that are required for structural integrity and stability is imperative for an improved understanding of the basic biology of these viruses, and for designing effective control strategies. Collectively, this thesis aims to elucidate the molecular determinants of structural stability and integrity in the Theiler’s murine encephalomyelitis virus capsid (TMEV). To study the TMEV GDVII capsid using biochemical techniques, neutralising polyclonal antibodies were generated against GDVII particles. The antibodies recognised linear epitopes in the C-terminus of the VP1 protein, but not those present in VP2 or VP3. The VP1 C-terminal residues were mapped to a loop above the putative receptor binding pit on the capsid surface, which prompted an investigation into the potential binding site of the TMEV co-receptor, heparan sulphate. Molecular docking revealed that heparan interacts with residues of the receptor binding pocket, as well as residues of the adjoining VP1 C-terminal loop. These findings suggest that the antibodies neutralise virus infection by preventing attachment of the virus to the co-receptor and possibly the unknown primary receptor. Few studies have identified the specific residues and interactions at subunit interfaces that significantly contribute to picornavirus capsid stability, assembly, and function. A novel in-silico screen was developed for the prediction of hotspot residues at protein-protein interfaces of a virus capsid. This screen can be applied to elucidate the residues that contribute significantly to the intraprotomer, interprotomer and interpentamer interfaces of any picornavirus capsid, on condition that the structure of the virus is available. The screen was applied to TMEV GDVII resulting in the identification of hotspots, several of which correspond to residues that are known to be important for aspects of the virus lifecycle, such as those that contribute to pH stability or form part of receptor binding sites. This observation suggests that residues involved in specific capsid functions may also play a role in capsid stability. Many of the residues identified as hotspots in TMEV corresponded to those required for assembly, uncoating, and virus growth in representative picornaviruses from various genera, suggesting that the residues that regulate capsid stability may be somewhat conserved across the family. Hotspots identified at the interpentamer interfaces of TMEV were individually substituted to alanine to further explore their importance to the TMEV lifecycle. All the amino acid substitutions prevented completion of the virus lifecycle as no CPE was observed following transfection of susceptible cells. Immunofluorescence experiments demonstrated that virus protein synthesis and RNA replication were not inhibited by substitution of the hotspot residues, but that infectivity was severely impeded. This confirmed that the residues were required for some aspect of the virus lifecycle, such as capsid assembly, or were critical for maintaining the conformational stability of the TMEV particles. Virus capsids become unstable and are prone to dissociation under certain conditions such as extreme pH and non-physiological temperatures. The thermostability of TMEV was explored by selecting GDVII virions with improved thermal tolerance through serial passage and heat exposure. Thermostable virions that could tolerate temperatures above 57 °C had reduced infective titres compared to the wild type TMEV suggesting that the virus adapted to thermal stress at the expense of viral fitness. Sequencing the capsid encoding regions of the mutant virions revealed a pair of amino acid substitutions that were present in all mutants. Additional substitutions that were unique to viruses selected at different temperatures were also identified. Most of the substitutions were located within the intraprotomer interfaces of the virus, unlike previous studies on enteroviruses where mutations were mostly localised to the receptor binding pocket. This thesis provides the first analysis of the structural determinants of TMEV capsid stability. The generation of tools to further explore the capsid structures of TMEV and other picornaviruses provides an opportunity for future studies which may contribute to the development of novel control strategies against this important family of viruses. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text: false
Enhanced photodynamic antimicrobial activity of surface modified SiNPs doped with zinc (II) phthalocyanines: The effect of antimicrobial ampicillin and extra charges from a sultone
- Magadla, Aviwe, Nyokong, Tebello
- Authors: Magadla, Aviwe , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186034 , vital:44457 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101996"
- Description: 1-(2-Methoxyethyl) piperidine sustituted Zn phthalocyanine complex (2) is synthesised and quartenised (3). These complexes are loaded into silica nanoparticles (SiNPs) that are futher surface modified with ampicillin and 1.3-propanesultone. The photophysical and photochemical properties of the complexes and their doped conjugates were investigated in dimethylsulfoxide. The cationic complex (3) is used for photodynamic antimicrobial activity. Log reduction values of above 9 are obtained towards the photoiactivation of Staphyloccocus aureus.
- Full Text:
- Authors: Magadla, Aviwe , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186034 , vital:44457 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101996"
- Description: 1-(2-Methoxyethyl) piperidine sustituted Zn phthalocyanine complex (2) is synthesised and quartenised (3). These complexes are loaded into silica nanoparticles (SiNPs) that are futher surface modified with ampicillin and 1.3-propanesultone. The photophysical and photochemical properties of the complexes and their doped conjugates were investigated in dimethylsulfoxide. The cationic complex (3) is used for photodynamic antimicrobial activity. Log reduction values of above 9 are obtained towards the photoiactivation of Staphyloccocus aureus.
- Full Text:
Elucidation of a novel role for HSP70/HSP90 organising protein (Hop) in mRNA processing
- Dingle, Laura Margaret Kirkpatrick
- Authors: Dingle, Laura Margaret Kirkpatrick
- Date: 2020
- Language: English
- Type: thesis , text , Doctoral , Ph.D
- Identifier: http://hdl.handle.net/10962/59173 , vital:27449 , doi:10.21504/10962/59173
- Description: Thesis (PhD.)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Authors: Dingle, Laura Margaret Kirkpatrick
- Date: 2020
- Language: English
- Type: thesis , text , Doctoral , Ph.D
- Identifier: http://hdl.handle.net/10962/59173 , vital:27449 , doi:10.21504/10962/59173
- Description: Thesis (PhD.)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
Investigating cannabinoids and endocannabinoid receptors as drug targets for pain and inflammation
- Authors: Marwarwa, Sinobomi Zamachi
- Date: 2020
- Subjects: Cannabinoids , Cannabinoids Receptors , Inflammation Alternative treatment , Pain Alternative treatment , Drug targeting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/164468 , vital:41121
- Description: Cannabinoids and the endocannabinoid system have been studied in the past decades but have yet to be fully understood. An insight into interactions that occur between cannabinoid compounds and their receptors is important for understanding the cannabinoids and the endocannabinoid system. Cannabinoids are natural products found in some cannabis plants, and they have similar effects to endocannabinoids, which are chemicals in the body that are involved many aspects of health from appetite, memory, and movement to pain, inflammation and response to cancer. Cannabinoids have a high impact on the treatment of pain and inflammation, they show different antinociceptive mechanisms to existing drugs like opioids, also, they have antimigraine properties better than those achieved by aspirin. The CB1 and CB2 human receptors have been the most studied cannabinoid receptors. In this project, we used a combination of mass-spectrometry to generate plausible chemical fragments and computational techniques to assess the binding of these fragments to these two main CB receptors. CB1 was adapted from the protein data bank (PBD), file 5U09 and the CB2 model was predicted using the hierarchical protocol I-TASSER, starting from the amino acid sequence in UniProt (P34972 CNR2_HUMAN). The proposed active site for CB1 was reported in a publication accompanying the 5U09 PDB model, which was originally generated with a pre-existing ligand in the active site. However, CB2 had to be built from a homology model and the active site determined using a combination of I-TASSER, Maestro, and CASTp the more favourable binding energies were determined by CASTp, leading to the use of the CASTp coordinates as default for docking in the CB2 human receptor. The molecular docking of cannabinoids THC, CBD, CBDV, CBG and CBN on both the CB1 and CB2 proteins was performed to identify the amino acids that interact with these compounds at their active sites. This would provide a guide to a future fragment-based drug discovery (FBDD) synthesis project. The docking in this work showed adequate accuracy with binding energies between -8.23 kcal/mol and -9.97 kcal/mol for CB1 and between -6.78 kcal/mol and -7.74 kcal/mol for CB2. An observation made was that binding energies of the CB1 human receptor docking were higher than those of the CB2 human receptor, which could support the widely held belief that CB1 is more important in cannabinoid interactions. The cannabinoids were then subjected to collision-induced dissociation to produce fragment structures predicted in chapter 2. These hypothetical fragments were docked in the CB1 and CB2 human receptor, the general trend again being the binding energies for the CB1 receptor was again around 10% higher than those of the CB2 receptor. As expected, larger fragments tended to have better binding, with the fragment proposed from m/z 259 with binding energies -9.62 kcal/mol in CB1 and -6.26 kcal/mol. Those fragments with significant lipophilic side chains or some aromatic moiety also showed good binding or around -6.00 kcal/mol, similar to the intact cannabinoids. In our case, this fragment was proposed from m/z 223 with binding energies -7.71 kcal/mol in CB1 and -6.5 kcal/mol in CB2. The results from the fragment dockings were favourable in that they have binding affinities lower than -6.0 kcal/mol which is good enough for the structures to be leads in the creation of fragment libraries. The docking was performed with Autodock 1.5.6 and data visualization with a discovery studio. , Thesis (MSc) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Authors: Marwarwa, Sinobomi Zamachi
- Date: 2020
- Subjects: Cannabinoids , Cannabinoids Receptors , Inflammation Alternative treatment , Pain Alternative treatment , Drug targeting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/164468 , vital:41121
- Description: Cannabinoids and the endocannabinoid system have been studied in the past decades but have yet to be fully understood. An insight into interactions that occur between cannabinoid compounds and their receptors is important for understanding the cannabinoids and the endocannabinoid system. Cannabinoids are natural products found in some cannabis plants, and they have similar effects to endocannabinoids, which are chemicals in the body that are involved many aspects of health from appetite, memory, and movement to pain, inflammation and response to cancer. Cannabinoids have a high impact on the treatment of pain and inflammation, they show different antinociceptive mechanisms to existing drugs like opioids, also, they have antimigraine properties better than those achieved by aspirin. The CB1 and CB2 human receptors have been the most studied cannabinoid receptors. In this project, we used a combination of mass-spectrometry to generate plausible chemical fragments and computational techniques to assess the binding of these fragments to these two main CB receptors. CB1 was adapted from the protein data bank (PBD), file 5U09 and the CB2 model was predicted using the hierarchical protocol I-TASSER, starting from the amino acid sequence in UniProt (P34972 CNR2_HUMAN). The proposed active site for CB1 was reported in a publication accompanying the 5U09 PDB model, which was originally generated with a pre-existing ligand in the active site. However, CB2 had to be built from a homology model and the active site determined using a combination of I-TASSER, Maestro, and CASTp the more favourable binding energies were determined by CASTp, leading to the use of the CASTp coordinates as default for docking in the CB2 human receptor. The molecular docking of cannabinoids THC, CBD, CBDV, CBG and CBN on both the CB1 and CB2 proteins was performed to identify the amino acids that interact with these compounds at their active sites. This would provide a guide to a future fragment-based drug discovery (FBDD) synthesis project. The docking in this work showed adequate accuracy with binding energies between -8.23 kcal/mol and -9.97 kcal/mol for CB1 and between -6.78 kcal/mol and -7.74 kcal/mol for CB2. An observation made was that binding energies of the CB1 human receptor docking were higher than those of the CB2 human receptor, which could support the widely held belief that CB1 is more important in cannabinoid interactions. The cannabinoids were then subjected to collision-induced dissociation to produce fragment structures predicted in chapter 2. These hypothetical fragments were docked in the CB1 and CB2 human receptor, the general trend again being the binding energies for the CB1 receptor was again around 10% higher than those of the CB2 receptor. As expected, larger fragments tended to have better binding, with the fragment proposed from m/z 259 with binding energies -9.62 kcal/mol in CB1 and -6.26 kcal/mol. Those fragments with significant lipophilic side chains or some aromatic moiety also showed good binding or around -6.00 kcal/mol, similar to the intact cannabinoids. In our case, this fragment was proposed from m/z 223 with binding energies -7.71 kcal/mol in CB1 and -6.5 kcal/mol in CB2. The results from the fragment dockings were favourable in that they have binding affinities lower than -6.0 kcal/mol which is good enough for the structures to be leads in the creation of fragment libraries. The docking was performed with Autodock 1.5.6 and data visualization with a discovery studio. , Thesis (MSc) -- Faculty of Science, Chemistry, 2020
- Full Text:
The Role of HSP70/HSP90 Organizing Protein (Hop) in the Heat Shock Factor 1 (HSF1)-mediated Stress Response
- Authors: Chakraborty, Abantika
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/163204 , vital:41018 , doi:10.21504/10962/163204
- Description: Molecular chaperones regulate cellular proteostasis. They control protein conformation and prevent misfolding and aggregation under both normal and stressful environments, ultimately resulting in cell survival. The project aimed to understand the role of the HSP70 – HSP90 Organizing Protein (Hop/STIP1) in the survival of stressed cells and the function of the stress-responsive transcription factor, Heat Shock Factor 1 (HSF1). HSF1 protein levels were significantly reduced in Hop-depleted HEK293T cells compared to controls by ELISA, western blot, and mass spectrometry. HSF1 transcriptional activity at the HSP70 promoter, and binding of a biotinylated HSE oligonucleotide under basal conditions were significantly reduced, consistent with the reduced levels of HSF1. In response to heat shock, HSF1 levels in Hop-depleted cells increased to that of controls, but there was still significantly lowerHSF1 transcriptional activity and HSE binding. Hop-depleted HEK293T cells were more sensitive than controls to the HSF1 inhibitor KRIBB11 and showed reduced short-term and long-term proliferation. Unlike the HSP90 inhibitor 17-DMAG, which had no effect, the HSP70 inhibitor JG98, further decreased the levels of HSF1 in Hop-depleted cells, suggesting a role for HSP70 in the Hop-mediated effects. There was punctate nuclear staining for HSF1 in Hop-depleted cells under both basal and heat shock conditions, as well as reduced nuclear localization and increased cytoplasmic accumulation of HSF1 in response to heat shock. Hop and HSF1 colocalized in cells, and HSF1 could be isolated in complex with Hop and HSP70. Loss of Hop reduced HSF1 in HSP70complexes but did not affect HSF1 abundance in HSP90 complexes. Hop-depleted cells showed reduced short-term and long-term survival compared to controls, an effect that was potentiated by the JG98 HSP70 inhibitor. Taken together, these data suggest that Hop regulation of HSF1activity is via a mechanism involving reductions in HSP70 interaction, as well as reduced nuclear localization, and DNA binding, and is consistent with reduced cellular fitness under basal and stress conditions. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Authors: Chakraborty, Abantika
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/163204 , vital:41018 , doi:10.21504/10962/163204
- Description: Molecular chaperones regulate cellular proteostasis. They control protein conformation and prevent misfolding and aggregation under both normal and stressful environments, ultimately resulting in cell survival. The project aimed to understand the role of the HSP70 – HSP90 Organizing Protein (Hop/STIP1) in the survival of stressed cells and the function of the stress-responsive transcription factor, Heat Shock Factor 1 (HSF1). HSF1 protein levels were significantly reduced in Hop-depleted HEK293T cells compared to controls by ELISA, western blot, and mass spectrometry. HSF1 transcriptional activity at the HSP70 promoter, and binding of a biotinylated HSE oligonucleotide under basal conditions were significantly reduced, consistent with the reduced levels of HSF1. In response to heat shock, HSF1 levels in Hop-depleted cells increased to that of controls, but there was still significantly lowerHSF1 transcriptional activity and HSE binding. Hop-depleted HEK293T cells were more sensitive than controls to the HSF1 inhibitor KRIBB11 and showed reduced short-term and long-term proliferation. Unlike the HSP90 inhibitor 17-DMAG, which had no effect, the HSP70 inhibitor JG98, further decreased the levels of HSF1 in Hop-depleted cells, suggesting a role for HSP70 in the Hop-mediated effects. There was punctate nuclear staining for HSF1 in Hop-depleted cells under both basal and heat shock conditions, as well as reduced nuclear localization and increased cytoplasmic accumulation of HSF1 in response to heat shock. Hop and HSF1 colocalized in cells, and HSF1 could be isolated in complex with Hop and HSP70. Loss of Hop reduced HSF1 in HSP70complexes but did not affect HSF1 abundance in HSP90 complexes. Hop-depleted cells showed reduced short-term and long-term survival compared to controls, an effect that was potentiated by the JG98 HSP70 inhibitor. Taken together, these data suggest that Hop regulation of HSF1activity is via a mechanism involving reductions in HSP70 interaction, as well as reduced nuclear localization, and DNA binding, and is consistent with reduced cellular fitness under basal and stress conditions. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
Taxonomic revision of the Natal mountain catfish, Amphilius natalensis (Siluriformes, Amphiliidae) in southern Africa
- Mazungula, Daniel Nkosinathi
- Authors: Mazungula, Daniel Nkosinathi
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164490 , vital:41123
- Description: Thesis (MSc)--Rhodes University, Department of Ichthyology and Fisheries Science, 2020
- Full Text:
- Authors: Mazungula, Daniel Nkosinathi
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164490 , vital:41123
- Description: Thesis (MSc)--Rhodes University, Department of Ichthyology and Fisheries Science, 2020
- Full Text:
Conceptualisations and pedagogical practices of academic literacy in Namibian higher education
- Authors: Julius, Lukas Homateni
- Date: 2021-04
- Subjects: Information literacy -- Study and teaching (Higher) -- Namibia , Academic writing -- Study and teaching -- Namibia , Qualitative research -- Methodology , Academic language -- Namibia , Information literacy -- Social aspects
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177293 , vital:42807 , 10.21504/10962/177293
- Description: The purpose of this study was to investigate academic literacy development lecturers’ conceptualisations of academic literacy and resultant pedagogical practices in academic development courses at three different Higher Education Institutional types in Namibia. The research sites were a Traditional University, a University of Technology and a Comprehensive University. The focus was to understand the extent to which the academics’ conceptions of academic literacy and the resultant pedagogical practices in the academic development courses at these three Higher Education Institutions (HEIs) facilitate epistemological access into students’ chosen fields of study. Bernstein’s Pedagogical theory (1990), Genre theory (1996) and Halliday’s Systemic Functional Linguistics (1978) were used as the study’s theoretical lenses and analytical framework. An interpretative paradigm and a qualitative case study design were employed as the research approach. Semi-structured interviews, classroom observations and documentary evidence were used to generate data. Research findings revealed a common (mis)conception of the nature of academic literacy, the resultant inadequate learning support offered to students in the selected academic literacy development courses, and a clear divorcing of academic literacy interventions from the students’ ‘home’ or mainstream disciplines at the three HEIs. The participants understood academic literacy from an autonomous position as a set of generic skills which could be taught outside of mainstream classes. Moreover, findings revealed that this understanding impacted on the design and assessments of all the academic literacy courses across the three universities under study. The study calls for a context sensitive model through which academic literacy acquisition can be scaffolded to meet the discipline-specific epistemological needs of the students. , Elalakano lyehokololoningomwa lyomapekapeko ndika olyo okukonakona ehumithokomeho lyomikalo dhokulesha nokushanga meilongngo lyopombada (oAcademic Literaci) maaputudhilongi, okukonakona omafatululo giisimanintsa moAcademic Literaci osho wo okutala iizemo yomikalo dhayooloka dhokulonga noku ilonga iilongwa yayooloka miiputudhilo yelongo lyopombada moNamibia. Omapekapeko ngaka oga li ga ningilwa miiputudhilo yomaukwatya ta ga landula; Oshiputudhiilo shopamudhigululwakalo, Oshiputudhilo shopaunongononi, nOshiputudilo shomailongo gaandjakana. Oshintsa shopokati shomapekapeko ngaka osho okuuva ko ondodo yowino osho wo euveko lyoAcademic Literaci maaputudhilongi nonkene euveko nontseyo ndjika tayi longithwa oku eta oshizemo tashi humitha komeho euveko lyopombanda lyaalongwa yomailongo geewino dhayooloka miiputudhilo itatu yelongo lyopombanda; shino otashi kwathele aalongwa yamone ontseyo ndjoka tayi ya kwathele meilongo lyawo. Omapekapeko ngano oga longitha omadhiladhiloukithi (eetheori) ga Bernstein’s Pedagogical theori (1990), Genre theori (1996) na Halliday’s Systemic Functional Linguistics theori (1978), mokufatulula nokundjandjukununa iizemo yomapekapeko. Omodela yokukonakona iizemo yongushu tayi ziilile maakonakonwa, oya tala ekonakono ndika onga oshintsa shopokati, oyo ya longithwa, opo ku monike uuyelele wothaathaa. Omikalo dha longifwa mokukonakona noku gongela uuyelele momapekapeko ngano ongaashi, eenkundathana dhayaali, omatalelo geetundi oshoyo omakonakono giinyanyangidhwa tayi kwandjangele nepekapeko ndika. Iizedjemo yepekapeko ndika otayi ulike kutya opena engwangwano montseyo nenge mefatululo lyuukwatya woAcademic Literaci, shoka sha eta enkundipalo meyambidhidho hali pewa aalongwa miilongwa yeewino dhayooloka. Shika otashi ulike kutya kapena etsokumwe pokati keenkambadhala tadhi ningwa kaapudhilongi dhokulonga oAcademic Litraci miilongwa ya yooloka mbyoka tayi ilongelwa kaalongwa miiputudhilo itatu yopombada. iizemmo yepekapeko olyo tuu mdika oya ulike wo kutya aalongwa mboka yaza komailongo ga yooloka oha yi ilongo nuudhigu opo ya pondole ondondo yomadhiladhilo gopombanda meilongo lyuukumwe. Mokukonakona euveko lyoAcademic Literaci, epekapeko ndika olya ndhindhilike kutya aakuthimbinga oyena euveko lyankundipala lyoterma ‘Academic Literaci,’ ano ya nyengwa okukwatakanitha oohedi dhopetameko ndhoka dhina oku ilongwa meikalekelo - ano pondje yiilongwa ikwao. Oshikwao, iizemo oya ulike kutya euveko ndika otali nwetha mo etungepo lyoAcademic Literaci onga oshilongwa, osho wo omakonakono gasho miiputudilo yombombanda itatu yakwatelwa momapekapeko. Hugunina, epekapeko ndika otali ulike/gandja oshiholelwa shomodela ndjoka oAcademic literacy tai vulu okulongwa opo yi kwatelemo eilongo lyiikwatelela kiilongwa osho yo komaitaalo nokeempumbwe dhaalongwa miiputudhilo yopombabda. , Thesis (PhD) -- Faculty of Education, Centre for Higher Education Research, Teaching and Learning (CHERTL), 2021
- Full Text:
- Authors: Julius, Lukas Homateni
- Date: 2021-04
- Subjects: Information literacy -- Study and teaching (Higher) -- Namibia , Academic writing -- Study and teaching -- Namibia , Qualitative research -- Methodology , Academic language -- Namibia , Information literacy -- Social aspects
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177293 , vital:42807 , 10.21504/10962/177293
- Description: The purpose of this study was to investigate academic literacy development lecturers’ conceptualisations of academic literacy and resultant pedagogical practices in academic development courses at three different Higher Education Institutional types in Namibia. The research sites were a Traditional University, a University of Technology and a Comprehensive University. The focus was to understand the extent to which the academics’ conceptions of academic literacy and the resultant pedagogical practices in the academic development courses at these three Higher Education Institutions (HEIs) facilitate epistemological access into students’ chosen fields of study. Bernstein’s Pedagogical theory (1990), Genre theory (1996) and Halliday’s Systemic Functional Linguistics (1978) were used as the study’s theoretical lenses and analytical framework. An interpretative paradigm and a qualitative case study design were employed as the research approach. Semi-structured interviews, classroom observations and documentary evidence were used to generate data. Research findings revealed a common (mis)conception of the nature of academic literacy, the resultant inadequate learning support offered to students in the selected academic literacy development courses, and a clear divorcing of academic literacy interventions from the students’ ‘home’ or mainstream disciplines at the three HEIs. The participants understood academic literacy from an autonomous position as a set of generic skills which could be taught outside of mainstream classes. Moreover, findings revealed that this understanding impacted on the design and assessments of all the academic literacy courses across the three universities under study. The study calls for a context sensitive model through which academic literacy acquisition can be scaffolded to meet the discipline-specific epistemological needs of the students. , Elalakano lyehokololoningomwa lyomapekapeko ndika olyo okukonakona ehumithokomeho lyomikalo dhokulesha nokushanga meilongngo lyopombada (oAcademic Literaci) maaputudhilongi, okukonakona omafatululo giisimanintsa moAcademic Literaci osho wo okutala iizemo yomikalo dhayooloka dhokulonga noku ilonga iilongwa yayooloka miiputudhilo yelongo lyopombada moNamibia. Omapekapeko ngaka oga li ga ningilwa miiputudhilo yomaukwatya ta ga landula; Oshiputudhiilo shopamudhigululwakalo, Oshiputudhilo shopaunongononi, nOshiputudilo shomailongo gaandjakana. Oshintsa shopokati shomapekapeko ngaka osho okuuva ko ondodo yowino osho wo euveko lyoAcademic Literaci maaputudhilongi nonkene euveko nontseyo ndjika tayi longithwa oku eta oshizemo tashi humitha komeho euveko lyopombanda lyaalongwa yomailongo geewino dhayooloka miiputudhilo itatu yelongo lyopombanda; shino otashi kwathele aalongwa yamone ontseyo ndjoka tayi ya kwathele meilongo lyawo. Omapekapeko ngano oga longitha omadhiladhiloukithi (eetheori) ga Bernstein’s Pedagogical theori (1990), Genre theori (1996) na Halliday’s Systemic Functional Linguistics theori (1978), mokufatulula nokundjandjukununa iizemo yomapekapeko. Omodela yokukonakona iizemo yongushu tayi ziilile maakonakonwa, oya tala ekonakono ndika onga oshintsa shopokati, oyo ya longithwa, opo ku monike uuyelele wothaathaa. Omikalo dha longifwa mokukonakona noku gongela uuyelele momapekapeko ngano ongaashi, eenkundathana dhayaali, omatalelo geetundi oshoyo omakonakono giinyanyangidhwa tayi kwandjangele nepekapeko ndika. Iizedjemo yepekapeko ndika otayi ulike kutya opena engwangwano montseyo nenge mefatululo lyuukwatya woAcademic Literaci, shoka sha eta enkundipalo meyambidhidho hali pewa aalongwa miilongwa yeewino dhayooloka. Shika otashi ulike kutya kapena etsokumwe pokati keenkambadhala tadhi ningwa kaapudhilongi dhokulonga oAcademic Litraci miilongwa ya yooloka mbyoka tayi ilongelwa kaalongwa miiputudhilo itatu yopombada. iizemmo yepekapeko olyo tuu mdika oya ulike wo kutya aalongwa mboka yaza komailongo ga yooloka oha yi ilongo nuudhigu opo ya pondole ondondo yomadhiladhilo gopombanda meilongo lyuukumwe. Mokukonakona euveko lyoAcademic Literaci, epekapeko ndika olya ndhindhilike kutya aakuthimbinga oyena euveko lyankundipala lyoterma ‘Academic Literaci,’ ano ya nyengwa okukwatakanitha oohedi dhopetameko ndhoka dhina oku ilongwa meikalekelo - ano pondje yiilongwa ikwao. Oshikwao, iizemo oya ulike kutya euveko ndika otali nwetha mo etungepo lyoAcademic Literaci onga oshilongwa, osho wo omakonakono gasho miiputudilo yombombanda itatu yakwatelwa momapekapeko. Hugunina, epekapeko ndika otali ulike/gandja oshiholelwa shomodela ndjoka oAcademic literacy tai vulu okulongwa opo yi kwatelemo eilongo lyiikwatelela kiilongwa osho yo komaitaalo nokeempumbwe dhaalongwa miiputudhilo yopombabda. , Thesis (PhD) -- Faculty of Education, Centre for Higher Education Research, Teaching and Learning (CHERTL), 2021
- Full Text:
Orchid mycorrhizal and endophytic fungal diversity of three co-occurring terrestrial orchids in the large African genus Disa (Orchidaceae)
- Khambule, Nondumiso Venessia
- Authors: Khambule, Nondumiso Venessia
- Date: 2020
- Subjects: Orchids South Africa , Mycorrhizal fungi South Africa , Endomycorrhizas South Africa , Endophytes , Orchids Roots
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/163341 , vital:41030
- Description: Orchids (in the family Orchidaceous) are one of the richest plant families and approximately 500 species are found in South Africa. A number of orchid species are found on disturbed areas and many of the terrestrial species grow in poor soils with low mineral nutrient availability. Most orchid species are thought to be associated with mycorrhizal fungi for germination and mycorrhiza provides nutrients for the survival of adult plants. The aim of this study was to select Orchidaceous plant species and to isolate, identify and characterize the orchid endophytes and assess these isolates for potential antimicrobial and enzymatic activities Isa is the largest genus in South Africa and three Disa species co-occurring in a small geographical area were selected. These included Disa bracteata, D. cornuta and D. polygonoides which span three sections of the genus. Roots were stained to confirm the mycorrhizal status of the Disa species. Mycorrhizal pelotons structures were microscopically observed inside root cells. The presence of pelotons is indictive of mycorrhizal fungal interactions within the orchid roots and areas associated with the site of nutrient exchange between plant and fungus. The presence of pelotons, however, does not give n indication of the fungal species involved. The endophytes were successfully isolated in pure cultures on potato dextrose agar (PDA). All slow growing isolates were selected, and further molecular identification undertaken; DNA was extracted, and PCR amplified using internal transcribed spacer (ITS1F and ITS4) fungal primers. The amplified products were then sequenced and analysed by comparison to sequences in the GenBank database. Trichoderma, Penicillium, Metapochonia, Talaromyces, Oidiodendron Neopestalotiopsis, and Chaetomium were identified from these sequences. The presence of other fungal root endophytes was suspected despite the rigorous surface sterilization procedure used. The primers used to amplify the ITS region are the universal barcoding primers which are specific to fungi. ITS1F is one of the primers designed to amplify a broad range of fungi. DNA was extracted from orchid roots and amplicons were cloned into a pGEMT plasmid vector. Individual clones were sequenced and aligned with Mega software and compared to sequences in the GenBank and UNITE database. Based on percentage sequence identity, unidentified Tulasnella species, Tullasnela colaspora, and various Ascomycota endophytes were identified as contributing to the endophytic root fungal diversity of the selected Disa species. The Disa species investigated in this study were associated with several soil endophytes. D. bracteata, D. polygonoides were collected from the same site along the road verge which is regarded as being disturbed. Based on both culture – dependent and independent techniques employed Oidiodendron was found associated with both species. Antimicrobial activity was determined using a well diffusion method using extracts from the isolated fungi against the bacterial isolates Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas puptida. Most of the isolated fungi showed at least one potential inhibition effect against one of the bacterial isolates. The extracts that showed potential antimicrobial activity could be further screened to determine the compounds produced as secondary metabolites using techniques such as LC-MS Enzymatic activities of protease, cellulose and amylase were determined using solid media amended with milk protein, carboxymethylcellulose (CMC) and starch. The majority of fungal isolates tested positive with amylase and cellulose with only a few fungal isolates testing positive for protease activity. Broth cultures containing CMC and starch were shown to enhance biomass production in approximately 40 % of the fungal isolates. Degradation of the substrates is required in order to provide carbon to the fungus under test in order to optimize fungal growth as well as to gain insight into their ecological role. Enzyme activity was evident particularly when cellulose and starch were provided as substrates. All the fungal isolates tested grew on the amended medium, with 40% of the isolates preferring to utilize CMC and/or starch, indicating the ability of these fungi to utilize various resources for carbon acquisitions. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Authors: Khambule, Nondumiso Venessia
- Date: 2020
- Subjects: Orchids South Africa , Mycorrhizal fungi South Africa , Endomycorrhizas South Africa , Endophytes , Orchids Roots
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/163341 , vital:41030
- Description: Orchids (in the family Orchidaceous) are one of the richest plant families and approximately 500 species are found in South Africa. A number of orchid species are found on disturbed areas and many of the terrestrial species grow in poor soils with low mineral nutrient availability. Most orchid species are thought to be associated with mycorrhizal fungi for germination and mycorrhiza provides nutrients for the survival of adult plants. The aim of this study was to select Orchidaceous plant species and to isolate, identify and characterize the orchid endophytes and assess these isolates for potential antimicrobial and enzymatic activities Isa is the largest genus in South Africa and three Disa species co-occurring in a small geographical area were selected. These included Disa bracteata, D. cornuta and D. polygonoides which span three sections of the genus. Roots were stained to confirm the mycorrhizal status of the Disa species. Mycorrhizal pelotons structures were microscopically observed inside root cells. The presence of pelotons is indictive of mycorrhizal fungal interactions within the orchid roots and areas associated with the site of nutrient exchange between plant and fungus. The presence of pelotons, however, does not give n indication of the fungal species involved. The endophytes were successfully isolated in pure cultures on potato dextrose agar (PDA). All slow growing isolates were selected, and further molecular identification undertaken; DNA was extracted, and PCR amplified using internal transcribed spacer (ITS1F and ITS4) fungal primers. The amplified products were then sequenced and analysed by comparison to sequences in the GenBank database. Trichoderma, Penicillium, Metapochonia, Talaromyces, Oidiodendron Neopestalotiopsis, and Chaetomium were identified from these sequences. The presence of other fungal root endophytes was suspected despite the rigorous surface sterilization procedure used. The primers used to amplify the ITS region are the universal barcoding primers which are specific to fungi. ITS1F is one of the primers designed to amplify a broad range of fungi. DNA was extracted from orchid roots and amplicons were cloned into a pGEMT plasmid vector. Individual clones were sequenced and aligned with Mega software and compared to sequences in the GenBank and UNITE database. Based on percentage sequence identity, unidentified Tulasnella species, Tullasnela colaspora, and various Ascomycota endophytes were identified as contributing to the endophytic root fungal diversity of the selected Disa species. The Disa species investigated in this study were associated with several soil endophytes. D. bracteata, D. polygonoides were collected from the same site along the road verge which is regarded as being disturbed. Based on both culture – dependent and independent techniques employed Oidiodendron was found associated with both species. Antimicrobial activity was determined using a well diffusion method using extracts from the isolated fungi against the bacterial isolates Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas puptida. Most of the isolated fungi showed at least one potential inhibition effect against one of the bacterial isolates. The extracts that showed potential antimicrobial activity could be further screened to determine the compounds produced as secondary metabolites using techniques such as LC-MS Enzymatic activities of protease, cellulose and amylase were determined using solid media amended with milk protein, carboxymethylcellulose (CMC) and starch. The majority of fungal isolates tested positive with amylase and cellulose with only a few fungal isolates testing positive for protease activity. Broth cultures containing CMC and starch were shown to enhance biomass production in approximately 40 % of the fungal isolates. Degradation of the substrates is required in order to provide carbon to the fungus under test in order to optimize fungal growth as well as to gain insight into their ecological role. Enzyme activity was evident particularly when cellulose and starch were provided as substrates. All the fungal isolates tested grew on the amended medium, with 40% of the isolates preferring to utilize CMC and/or starch, indicating the ability of these fungi to utilize various resources for carbon acquisitions. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
Decorated titania fibers as photocatalysts for hydrogen generation and organic matter degradation
- Mapukata, Sivuyisiwe, Hainer, Andrew S, Lanterna, Anabel E, Scaiano, Juan C, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
Formulation and characterisation of a combination captopril and hydrochlorothiazide microparticulate dosage form for paediatric use
- Chikukwa, Mellisa Tafadzwa Ruramai
- Authors: Chikukwa, Mellisa Tafadzwa Ruramai
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163216 , vital:41019 , doi:10.21504/10962/163216
- Description: Thesis (PhD)--Rhodes University, Pharmacy Faculty, Department of Pharmaceutics, 2020
- Full Text:
- Authors: Chikukwa, Mellisa Tafadzwa Ruramai
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163216 , vital:41019 , doi:10.21504/10962/163216
- Description: Thesis (PhD)--Rhodes University, Pharmacy Faculty, Department of Pharmaceutics, 2020
- Full Text:
Softboi
- Authors: Mall, Shireen
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164373 , vital:41113
- Description: Thesis (MA)--Rhodes University, Faculty of Humanities, School of Languages, 2020
- Full Text:
- Authors: Mall, Shireen
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MA
- Identifier: http://hdl.handle.net/10962/164373 , vital:41113
- Description: Thesis (MA)--Rhodes University, Faculty of Humanities, School of Languages, 2020
- Full Text:
Development and assessment of a fixed dose combination of perindopril arginine and indapamide loaded microparticles
- Authors: Mandava, Tavonga Tyomai
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164413 , vital:41116
- Description: Thesis (MSc)--Rhodes University, Faculty of Pharmacy, Pharmaceutics, 2020
- Full Text:
- Authors: Mandava, Tavonga Tyomai
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164413 , vital:41116
- Description: Thesis (MSc)--Rhodes University, Faculty of Pharmacy, Pharmaceutics, 2020
- Full Text:
An evaluation of the cytotoxic activities of novel artemisinin derivatives: towards targeted therapies for triple-negative breast cancers (TNBC)
- Authors: Kajewole, Deborah Ifeoluwa
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163329 , vital:41029 , doi:10.21504/10962/163329
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
- Authors: Kajewole, Deborah Ifeoluwa
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/163329 , vital:41029 , doi:10.21504/10962/163329
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020.
- Full Text:
Editorial for Special Issue: Education for Sustainability in a Time of Crises
- Authors: Rosenberg, Eureta
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370533 , vital:66352 , xlink:href="10.4314/sajee.v36i1.1"
- Description: There is an old and still popular saying that a crisis is an opportunity for change. The Chinese symbol for crisis is translated in Wikipedia as “danger at a point of juncture”. In the year 2020, first China and then the rest of humanity have been presented with a monumental crisis: a new and lethal virus that spread fast and far, causing actions and reactions, with dramatic consequences for social and economic life around the globe. Rebecca Solnit wrote of another crisis in her book Hope in the Dark: The Untold Story of People Power. In Grounds for Hope, a foreword to the 2015 edition (p.2), she stated: “This is an extraordinary time full of vital, transformative movements, that could not be foreseen. It’s also a nightmarish time. Full engagement requires the ability to perceive both.”.
- Full Text:
- Authors: Rosenberg, Eureta
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370533 , vital:66352 , xlink:href="10.4314/sajee.v36i1.1"
- Description: There is an old and still popular saying that a crisis is an opportunity for change. The Chinese symbol for crisis is translated in Wikipedia as “danger at a point of juncture”. In the year 2020, first China and then the rest of humanity have been presented with a monumental crisis: a new and lethal virus that spread fast and far, causing actions and reactions, with dramatic consequences for social and economic life around the globe. Rebecca Solnit wrote of another crisis in her book Hope in the Dark: The Untold Story of People Power. In Grounds for Hope, a foreword to the 2015 edition (p.2), she stated: “This is an extraordinary time full of vital, transformative movements, that could not be foreseen. It’s also a nightmarish time. Full engagement requires the ability to perceive both.”.
- Full Text:
CO2-induced woody thickening depends strongly on interacting abiotic and biotic factors
- Authors: Raubenheimer, Sarah Lynn
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164646 , vital:41151 , doi:10.21504/10962/164646
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Botany, 2020
- Full Text:
- Authors: Raubenheimer, Sarah Lynn
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164646 , vital:41151 , doi:10.21504/10962/164646
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Botany, 2020
- Full Text:
Enhancement of photodynamic antimicrobialtherapy through the use of cationic indium porphyrin conjugated to Ag/CuFe2O4 nanoparticles
- Makola, Collen L, Managa, Muthumuni, Nyokong, Tebello
- Authors: Makola, Collen L , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186233 , vital:44475 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101736"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is being actively researched as a possible alternative for antimicrobial agents. This study focuses on the application of neutral indium 5-p-carboxyphenyl-10-15-20-(tri-4-pyridyl)porphyrin and cationic indium 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridyl)-porphyrin triiodide conjugated to 6-mercapo-1-hexanol functionalized Ag/CuFe2O4 magnetic nanoparticles for photo-inactivation of S. aureus bacteria. Comparative studies were done on quaternized and unquaternized indium porphyrin complexes conjugated to Ag/CuFe2O4, where log reduction of 9.27 was obtained for quaternized conjugate and 0.83 for unquaternized conjugate.
- Full Text:
- Authors: Makola, Collen L , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186233 , vital:44475 , xlink:href="https://doi.org/10.1016/j.pdpdt.2020.101736"
- Description: Photodynamic antimicrobial chemotherapy (PACT) is being actively researched as a possible alternative for antimicrobial agents. This study focuses on the application of neutral indium 5-p-carboxyphenyl-10-15-20-(tri-4-pyridyl)porphyrin and cationic indium 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridyl)-porphyrin triiodide conjugated to 6-mercapo-1-hexanol functionalized Ag/CuFe2O4 magnetic nanoparticles for photo-inactivation of S. aureus bacteria. Comparative studies were done on quaternized and unquaternized indium porphyrin complexes conjugated to Ag/CuFe2O4, where log reduction of 9.27 was obtained for quaternized conjugate and 0.83 for unquaternized conjugate.
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