Establishing computational approaches towards identifying malarial allosteric modulators: a case study of plasmodium falciparum hsp70s
- Amusengeri, Arnold, Astl, Lindy, Lobb, Kevin A, Verkhivker, Gennady M, Tastan Bishop, Özlem
- Authors: Amusengeri, Arnold , Astl, Lindy , Lobb, Kevin A , Verkhivker, Gennady M , Tastan Bishop, Özlem
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163000 , vital:41003 , https://doi.org/10.3390/ijms20225574
- Description: Combating malaria is almost a never-ending battle, as Plasmodium parasites develop resistance to the drugs used against them, as observed recently in artemisinin-based combination therapies. The main concern now is if the resistant parasite strains spread from Southeast Asia to Africa, the continent hosting most malaria cases. To prevent catastrophic results, we need to find non-conventional approaches. Allosteric drug targeting sites and modulators might be a new hope for malarial treatments. Heat shock proteins (HSPs) are potential malarial drug targets and have complex allosteric control mechanisms. Yet, studies on designing allosteric modulators against them are limited. Here, we identified allosteric modulators (SANC190 and SANC651) against P. falciparum Hsp70-1 and Hsp70-x, affecting the conformational dynamics of the proteins, delicately balanced by the endogenous ligands. Previously, we established a pipeline to identify allosteric sites and modulators. This study also further investigated alternative approaches to speed up the process by comparing all atom molecular dynamics simulations and dynamic residue network analysis with the coarse-grained (CG) versions of the calculations. Betweenness centrality (BC) profiles for PfHsp70-1 and PfHsp70-x derived from CG simulations not only revealed similar trends but also pointed to the same functional regions and specific residues corresponding to BC profile peaks.
- Full Text:
- Date Issued: 2019
- Authors: Amusengeri, Arnold , Astl, Lindy , Lobb, Kevin A , Verkhivker, Gennady M , Tastan Bishop, Özlem
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163000 , vital:41003 , https://doi.org/10.3390/ijms20225574
- Description: Combating malaria is almost a never-ending battle, as Plasmodium parasites develop resistance to the drugs used against them, as observed recently in artemisinin-based combination therapies. The main concern now is if the resistant parasite strains spread from Southeast Asia to Africa, the continent hosting most malaria cases. To prevent catastrophic results, we need to find non-conventional approaches. Allosteric drug targeting sites and modulators might be a new hope for malarial treatments. Heat shock proteins (HSPs) are potential malarial drug targets and have complex allosteric control mechanisms. Yet, studies on designing allosteric modulators against them are limited. Here, we identified allosteric modulators (SANC190 and SANC651) against P. falciparum Hsp70-1 and Hsp70-x, affecting the conformational dynamics of the proteins, delicately balanced by the endogenous ligands. Previously, we established a pipeline to identify allosteric sites and modulators. This study also further investigated alternative approaches to speed up the process by comparing all atom molecular dynamics simulations and dynamic residue network analysis with the coarse-grained (CG) versions of the calculations. Betweenness centrality (BC) profiles for PfHsp70-1 and PfHsp70-x derived from CG simulations not only revealed similar trends but also pointed to the same functional regions and specific residues corresponding to BC profile peaks.
- Full Text:
- Date Issued: 2019
Understanding the Pyrimethamine drug resistance mechanism via combined molecular dynamics and dynamic residue network analysis:
- Amusengeri, Arnold, Tata, Rolland B, Tastan Bishop, Özlem
- Authors: Amusengeri, Arnold , Tata, Rolland B , Tastan Bishop, Özlem
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163022 , vital:41005 , https://doi.org/10.3390/molecules25040904
- Description: In this era of precision medicine, insights into the resistance mechanism of drugs are integral for the development of potent therapeutics. Here, we sought to understand the contribution of four point mutations (N51I, C59R, S108N, and I164L) within the active site of the malaria parasite enzyme dihydrofolate reductase (DHFR) towards the resistance of the antimalarial drug pyrimethamine. Homology modeling was used to obtain full-length models of wild type (WT) and mutant DHFR. Molecular docking was employed to dock pyrimethamine onto the generated structures. Subsequent all-atom molecular dynamics (MD) simulations and binding free-energy computations highlighted that pyrimethamine’s stability and affinity inversely relates to the number of mutations within its binding site and, hence, resistance severity.
- Full Text:
- Date Issued: 2020
- Authors: Amusengeri, Arnold , Tata, Rolland B , Tastan Bishop, Özlem
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163022 , vital:41005 , https://doi.org/10.3390/molecules25040904
- Description: In this era of precision medicine, insights into the resistance mechanism of drugs are integral for the development of potent therapeutics. Here, we sought to understand the contribution of four point mutations (N51I, C59R, S108N, and I164L) within the active site of the malaria parasite enzyme dihydrofolate reductase (DHFR) towards the resistance of the antimalarial drug pyrimethamine. Homology modeling was used to obtain full-length models of wild type (WT) and mutant DHFR. Molecular docking was employed to dock pyrimethamine onto the generated structures. Subsequent all-atom molecular dynamics (MD) simulations and binding free-energy computations highlighted that pyrimethamine’s stability and affinity inversely relates to the number of mutations within its binding site and, hence, resistance severity.
- Full Text:
- Date Issued: 2020
Paper recycling patterns and potential interventions in the education sector: A case study of paper streams at Rhodes University, South Africa
- Amutenya, N, Shackleton, Charlie M, Whittington-Jones, Kevin J
- Authors: Amutenya, N , Shackleton, Charlie M , Whittington-Jones, Kevin J
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181180 , vital:43705 , xlink:href="https://doi.org/10.1016/j.resconrec.2008.12.001"
- Description: This paper considers the use of paper by academics and student computer laboratories at Rhodes University as a basis for identifying areas to reduce the amounts used and increase rates of recycling. A sample of 50 academic staff monitored the volume and purpose of the paper they used over 5 months, and the procurement officers in all the academic departments were interviewed regarding the total amount of paper used per academic department. Mean use was 34 ± 20 new sheets of paper per working day, of which 3% were trashed, 15% were kept for later use (as scrap or printed on the opposite side) and 79% were given out as notes to students, filed as records or posted out as mail to other departments or institutions. There was a significant relationship between number of students served by a department and the overall demand for paper, as well the number of staff per department and the number of recycling bins. The university could save approximately US$ 7000 per year for every 10% reduction in current use of paper (12,784 reams/year). Reduction in paper usage could be achieved through an increase in re-use of paper, printing handouts for students on both sides of each sheet of paper and by investing in printers that are capable of printing on both sides of a sheet of paper. Double-sided printers are only 20–25% more expensive than single-sided ones, but will potentially reduce paper usage by half. A 40% reduction would save the university approximately US $ 20,000 per year in direct costs, and more in reduced waste streams, as well as help promote the environmental image of the university. On a per unit basis, the higher costs for a double-sided printer in offices would be repaid in 9 months or less through reduced paper use.
- Full Text:
- Date Issued: 2009
- Authors: Amutenya, N , Shackleton, Charlie M , Whittington-Jones, Kevin J
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181180 , vital:43705 , xlink:href="https://doi.org/10.1016/j.resconrec.2008.12.001"
- Description: This paper considers the use of paper by academics and student computer laboratories at Rhodes University as a basis for identifying areas to reduce the amounts used and increase rates of recycling. A sample of 50 academic staff monitored the volume and purpose of the paper they used over 5 months, and the procurement officers in all the academic departments were interviewed regarding the total amount of paper used per academic department. Mean use was 34 ± 20 new sheets of paper per working day, of which 3% were trashed, 15% were kept for later use (as scrap or printed on the opposite side) and 79% were given out as notes to students, filed as records or posted out as mail to other departments or institutions. There was a significant relationship between number of students served by a department and the overall demand for paper, as well the number of staff per department and the number of recycling bins. The university could save approximately US$ 7000 per year for every 10% reduction in current use of paper (12,784 reams/year). Reduction in paper usage could be achieved through an increase in re-use of paper, printing handouts for students on both sides of each sheet of paper and by investing in printers that are capable of printing on both sides of a sheet of paper. Double-sided printers are only 20–25% more expensive than single-sided ones, but will potentially reduce paper usage by half. A 40% reduction would save the university approximately US $ 20,000 per year in direct costs, and more in reduced waste streams, as well as help promote the environmental image of the university. On a per unit basis, the higher costs for a double-sided printer in offices would be repaid in 9 months or less through reduced paper use.
- Full Text:
- Date Issued: 2009
Action for increasing energy-saving behaviour in student residences at Rhodes University, South Africa
- Ancha, Angel, Bulunga, Lindelwa, Thondhlana, Gladman
- Authors: Ancha, Angel , Bulunga, Lindelwa , Thondhlana, Gladman
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67801 , vital:29146 , https://doi.org/10.1108/IJSHE-07-2017-0107
- Description: Publisher version , Purpose: In response to increasing energy demand and financial constraints to invest in green infrastructure, behaviour change energy-saving interventions are increasingly being considered as a tool for encouraging pro-environmental behaviour in campus residences. This paper aims to report on a pilot programme aimed at reducing energy consumption via behaviour change interventions, variably applied in residences at Rhodes University, South Africa. Design/methodology/approach: Data were collected via structured questionnaires, energy consumption records and post-intervention programme focus group discussions. Findings: Participant residences that received a mix of different interventions in the forms of pamphlets, face-to-face discussions, incentives and feedback recorded more energy reductions of up to 9 per cent than residences that received a single or no intervention. In post-experiment discussions, students cited personal, institutional and structural barriers to pro-environmental energy-use behaviour. Practical implications: Overall, the results of this study suggest that information provision of energy-saving tips combined with regular feedback and incentives can result in energy-use reductions in university residences, which may yield environmental and economic benefits for universities, but addressing barriers to pro-environmental behaviour might maximise the results. Originality/value: Given the lack of literature on energy conservation in the global South universities, this study provides the basis for discussing the potential for using behavioural interventions in universities for stirring pathways towards sustainability.
- Full Text: false
- Date Issued: 2018
- Authors: Ancha, Angel , Bulunga, Lindelwa , Thondhlana, Gladman
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67801 , vital:29146 , https://doi.org/10.1108/IJSHE-07-2017-0107
- Description: Publisher version , Purpose: In response to increasing energy demand and financial constraints to invest in green infrastructure, behaviour change energy-saving interventions are increasingly being considered as a tool for encouraging pro-environmental behaviour in campus residences. This paper aims to report on a pilot programme aimed at reducing energy consumption via behaviour change interventions, variably applied in residences at Rhodes University, South Africa. Design/methodology/approach: Data were collected via structured questionnaires, energy consumption records and post-intervention programme focus group discussions. Findings: Participant residences that received a mix of different interventions in the forms of pamphlets, face-to-face discussions, incentives and feedback recorded more energy reductions of up to 9 per cent than residences that received a single or no intervention. In post-experiment discussions, students cited personal, institutional and structural barriers to pro-environmental energy-use behaviour. Practical implications: Overall, the results of this study suggest that information provision of energy-saving tips combined with regular feedback and incentives can result in energy-use reductions in university residences, which may yield environmental and economic benefits for universities, but addressing barriers to pro-environmental behaviour might maximise the results. Originality/value: Given the lack of literature on energy conservation in the global South universities, this study provides the basis for discussing the potential for using behavioural interventions in universities for stirring pathways towards sustainability.
- Full Text: false
- Date Issued: 2018
Archaeopteris (Progymnospermopsida) from the Devonian of southern Africa
- Anderson, Heidi M, Hiller, Norton, Gess, Robert W
- Authors: Anderson, Heidi M , Hiller, Norton , Gess, Robert W
- Date: 1995
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72712 , vital:30102 , https://doi.org/10.1111/j.1095-8339.1995.tb02593.x
- Description: Archaeopteris notosaria sp. nov. based on one fertile and numerous sterile leafy branches is described from the Grahamstown By-Pass locality, Witpoort Formation (Witteberg Group) Upper Devonian, and represents the first unequivocal record of the genus in southern Africa. This occurrence is used, in its palaeogeographical context, to support the suggestion that climatic gradients in Late Devonian times were less steep than they are at present.
- Full Text: false
- Date Issued: 1995
- Authors: Anderson, Heidi M , Hiller, Norton , Gess, Robert W
- Date: 1995
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72712 , vital:30102 , https://doi.org/10.1111/j.1095-8339.1995.tb02593.x
- Description: Archaeopteris notosaria sp. nov. based on one fertile and numerous sterile leafy branches is described from the Grahamstown By-Pass locality, Witpoort Formation (Witteberg Group) Upper Devonian, and represents the first unequivocal record of the genus in southern Africa. This occurrence is used, in its palaeogeographical context, to support the suggestion that climatic gradients in Late Devonian times were less steep than they are at present.
- Full Text: false
- Date Issued: 1995
An unusual new fossil shark (Pisces: Chondrichthyes) from the Late Devonian of South Africa
- Anderson, M Eric, Long, John A, Gess, Robert W, Hiller, Norton
- Authors: Anderson, M Eric , Long, John A , Gess, Robert W , Hiller, Norton
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73910 , vital:30240 , http://museum.wa.gov.au/sites/default/files/10. Anderson, Long, Gess, Hiller.pdf
- Description: A new stem-group chondrichthyan fish, PlesioselacJllIs macracanthlls gen. et sp. nov., is described from the Late Devonian Witpoort Formation, representing an estuarine lagoon site, near Grahamstown, South Africa. Based on a single, fairly complete specimen, it is distinctive in its a single dorsal fin braced by a large, stout spine with numerous ribs and posterior denticles, apparently no second dorsal or anal fin, an amphistylic jaw suspension, and a distinctive triangular palatoquadrate. It is suggested that the species may represent a high-latitude, Late Devonian relict taxon.
- Full Text:
- Date Issued: 1999
- Authors: Anderson, M Eric , Long, John A , Gess, Robert W , Hiller, Norton
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73910 , vital:30240 , http://museum.wa.gov.au/sites/default/files/10. Anderson, Long, Gess, Hiller.pdf
- Description: A new stem-group chondrichthyan fish, PlesioselacJllIs macracanthlls gen. et sp. nov., is described from the Late Devonian Witpoort Formation, representing an estuarine lagoon site, near Grahamstown, South Africa. Based on a single, fairly complete specimen, it is distinctive in its a single dorsal fin braced by a large, stout spine with numerous ribs and posterior denticles, apparently no second dorsal or anal fin, an amphistylic jaw suspension, and a distinctive triangular palatoquadrate. It is suggested that the species may represent a high-latitude, Late Devonian relict taxon.
- Full Text:
- Date Issued: 1999
The first Bothriolepsis-associated Devonian fish fauna from Africa
- Anderson, M Eric, Hiller, Norton, Gess, Robert W
- Authors: Anderson, M Eric , Hiller, Norton , Gess, Robert W
- Date: 1994
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73852 , vital:30235 , https://journals.co.za/content/sajsci/90/7/AJA00382353_5900
- Description: An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.
- Full Text:
- Date Issued: 1994
- Authors: Anderson, M Eric , Hiller, Norton , Gess, Robert W
- Date: 1994
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73852 , vital:30235 , https://journals.co.za/content/sajsci/90/7/AJA00382353_5900
- Description: An advanced diplacanthid (Climatiiformes) is described from a Famennian estuarine environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fin spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.
- Full Text:
- Date Issued: 1994
Melatonin alters the photodegradation of paracetamol
- Anoopkumar-Dukie, Shailendra, Glass, Beverley D, Walker, Roderick B, Daya, Santylal
- Authors: Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184357 , vital:44211 , xlink:href="https://doi.org/10.1211/146080800128735755"
- Description: The effects of melatonin, a known free-radical scavenger, on paracetamol in the presence of UV irradiation was studied by use of HPLC. The experiments were performed in air and nitrogen. The results show that the rate of photodegradation of melatonin is faster in air than in nitrogen whereas that of paracetamol is similar in air and nitrogen. When the two drugs were combined, melatonin retarded the degradation of paracetamol for up to 6h in the presence of nitrogen. However, in the presence of air melatonin rapidly enhances the photodegradation of paracetamol. This study shows that a combination of melatonin and paracetamol in the presence of air and UV irradiation can lead to rapid inactivation of both agents, thus raising important concerns about the possible use of melatonin as sunscreen
- Full Text:
- Date Issued: 2000
- Authors: Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184357 , vital:44211 , xlink:href="https://doi.org/10.1211/146080800128735755"
- Description: The effects of melatonin, a known free-radical scavenger, on paracetamol in the presence of UV irradiation was studied by use of HPLC. The experiments were performed in air and nitrogen. The results show that the rate of photodegradation of melatonin is faster in air than in nitrogen whereas that of paracetamol is similar in air and nitrogen. When the two drugs were combined, melatonin retarded the degradation of paracetamol for up to 6h in the presence of nitrogen. However, in the presence of air melatonin rapidly enhances the photodegradation of paracetamol. This study shows that a combination of melatonin and paracetamol in the presence of air and UV irradiation can lead to rapid inactivation of both agents, thus raising important concerns about the possible use of melatonin as sunscreen
- Full Text:
- Date Issued: 2000
A sensitive and reliable method for the detection of lipid peroxidation in biological tissues
- Anoopkumar-Dukie, Shailendra, Walker, Roderick B, Daya, Santylal
- Authors: Anoopkumar-Dukie, Shailendra , Walker, Roderick B , Daya, Santylal
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184325 , vital:44208 , xlink:href="https://doi.org/10.1211/0022357011775299"
- Description: A simple, accurate and cost effective method has been designed for the determination of lipid peroxidation in biological tissue samples. The method was a modification and improvement on existing methods available for lipid peroxidation determination. Solid-phase extraction was used to separate the thiobarbituric acid–malondialdehyde complex from thiobarbituric acidreactive substances and HPLC was performed using a C18 (Waters Spherisorb, 5 µm, 250¬4.6 mm i.d.) column to achieve isolation of the complex. The procedure was validated with respect to linearity of calibration (0.998), precision, sensitivity and limits of quantitation (1 nmol mL−1) and detection (0.5 nmol mL−1). Resorcinol was used as an external standard. The method was tested by inducing free radical generation with a known free radical generator, quinolinic acid, in rat brain homogenate. The results showed that the method presented allowed detection of lipid peroxidation products at concentrations in the nanomolar (nM) range compared with the micromolar (µM) range detected by other methods, thus rendering it suitable for use with biological samples. In addition, the modified method allowed for detection of the purified lipid peroxidation products, thus eliminating the possibility of simultaneous detection of impurities that absorb at the same wavelength.
- Full Text:
- Date Issued: 2001
- Authors: Anoopkumar-Dukie, Shailendra , Walker, Roderick B , Daya, Santylal
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184325 , vital:44208 , xlink:href="https://doi.org/10.1211/0022357011775299"
- Description: A simple, accurate and cost effective method has been designed for the determination of lipid peroxidation in biological tissue samples. The method was a modification and improvement on existing methods available for lipid peroxidation determination. Solid-phase extraction was used to separate the thiobarbituric acid–malondialdehyde complex from thiobarbituric acidreactive substances and HPLC was performed using a C18 (Waters Spherisorb, 5 µm, 250¬4.6 mm i.d.) column to achieve isolation of the complex. The procedure was validated with respect to linearity of calibration (0.998), precision, sensitivity and limits of quantitation (1 nmol mL−1) and detection (0.5 nmol mL−1). Resorcinol was used as an external standard. The method was tested by inducing free radical generation with a known free radical generator, quinolinic acid, in rat brain homogenate. The results showed that the method presented allowed detection of lipid peroxidation products at concentrations in the nanomolar (nM) range compared with the micromolar (µM) range detected by other methods, thus rendering it suitable for use with biological samples. In addition, the modified method allowed for detection of the purified lipid peroxidation products, thus eliminating the possibility of simultaneous detection of impurities that absorb at the same wavelength.
- Full Text:
- Date Issued: 2001
Indomethacin reduces lipid peroxidation in rat brain homogenate by binding Fe2+
- Anoopkumar-Dukie, Shailendra, Lack, Barbara, McPhail, Kerry L, Nyokong, Tebello, Lambat, Zaynab, Maharaj, Deepat, Daya, Santy
- Authors: Anoopkumar-Dukie, Shailendra , Lack, Barbara , McPhail, Kerry L , Nyokong, Tebello , Lambat, Zaynab , Maharaj, Deepat , Daya, Santy
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304763 , vital:58487 , xlink:href="https://doi.org/10.1023/A:1021958016928"
- Description: One of the hallmarks of Alzheimer's disease (AD) is the progressive degeneration of cholinergic neurons in the cerebral cortex and hippocampus. It is generally accepted that this neuronal degeneration is due to free-radical-induced damage. These free radicals attack vital structural components of the neurons. This implies that agents that reduce free radical generation could potentially delay the progression of AD. Free radical generation in the brain is assisted by the presence of iron, required by the Fenton reaction. Thus, agents that reduce iron availability for this reaction could potentially reduce free radical formation. Since non steroidal anti-inflammatory drugs (NSAIDS) have been shown to reduce the severity of AD, we investigated the possible mechanism by which indomethacin could afford neuroprotection. Our results show that indomethacin (1 mM) is able to reduce the iron-induced rise in lipid peroxidation in rat brain homogenates. In addition, our NMR data indicate that indomethacin binds the Fe2+/Fe3+ ion. This was confirmed by a study using UV/Vis spectrophotometry. The results imply that indomethacin provides a neuroprotective effect by binding to iron and thus making it unavailable for free radical production.
- Full Text:
- Date Issued: 2003
- Authors: Anoopkumar-Dukie, Shailendra , Lack, Barbara , McPhail, Kerry L , Nyokong, Tebello , Lambat, Zaynab , Maharaj, Deepat , Daya, Santy
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304763 , vital:58487 , xlink:href="https://doi.org/10.1023/A:1021958016928"
- Description: One of the hallmarks of Alzheimer's disease (AD) is the progressive degeneration of cholinergic neurons in the cerebral cortex and hippocampus. It is generally accepted that this neuronal degeneration is due to free-radical-induced damage. These free radicals attack vital structural components of the neurons. This implies that agents that reduce free radical generation could potentially delay the progression of AD. Free radical generation in the brain is assisted by the presence of iron, required by the Fenton reaction. Thus, agents that reduce iron availability for this reaction could potentially reduce free radical formation. Since non steroidal anti-inflammatory drugs (NSAIDS) have been shown to reduce the severity of AD, we investigated the possible mechanism by which indomethacin could afford neuroprotection. Our results show that indomethacin (1 mM) is able to reduce the iron-induced rise in lipid peroxidation in rat brain homogenates. In addition, our NMR data indicate that indomethacin binds the Fe2+/Fe3+ ion. This was confirmed by a study using UV/Vis spectrophotometry. The results imply that indomethacin provides a neuroprotective effect by binding to iron and thus making it unavailable for free radical production.
- Full Text:
- Date Issued: 2003
SEAmester – South Africa’s first class afloat
- Ansorge, Isabelle J, Brundrit, Geoff, Brundrit, Jean, Dorrington, Rosemary A, Fawcett, Sarah, Gammon, David, Henry, Tahlia, Hermes, Juliet, Hölscher, Beate, d’Hotman, Jethan, Meiklejohn, Ian, Morris, Tammy, Pinto, Izidine, Du Plessis, Marcel, Roman, Raymond, Saunders, Clinton, Shabangu, Fannie W, De Vos, Marc, Walker, David R, Louw, Gavin
- Authors: Ansorge, Isabelle J , Brundrit, Geoff , Brundrit, Jean , Dorrington, Rosemary A , Fawcett, Sarah , Gammon, David , Henry, Tahlia , Hermes, Juliet , Hölscher, Beate , d’Hotman, Jethan , Meiklejohn, Ian , Morris, Tammy , Pinto, Izidine , Du Plessis, Marcel , Roman, Raymond , Saunders, Clinton , Shabangu, Fannie W , De Vos, Marc , Walker, David R , Louw, Gavin
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65539 , vital:28808 , https://doi.org/10.17159/sajs.2016/a0171
- Description: publisher version , From Introduction: Marine science is a highly competitive environment. The need to improve the cohort of South African postgraduates, who would be recognised both nationally and internationally for their scientific excellence, is crucial. It is possible to attract students early on in their careers to this discipline via cutting-edge science, technology and unique field experiences. Through the engagement of students with real-life experiences such as SEAmester, universities supporting marine science postgraduate degree programmes can attract a sustainable throughput of numerically proficient students. By achieving a more quantitative and experienced input into our postgraduate degree programmes, we will, as a scientific community, greatly improve our long-term capabilities to accurately measure, model and predict the impacts of current climate change scenarios. The short-term goal is to attract and establish a cohort of proficient marine and atmospheric science graduates who will contribute to filling the capacity needs of South African marine science as a whole. The SEAmester programme, by involving researchers from across all the relevant disciplines and tertiary institutions, provides an opportunity to build a network of collaborative teaching within the marine field. In doing so, these researchers will foster and strengthen new and current collaborations between historically white and black universities (Figure 1). The long-term objective of SEAmester is to build critical mass within the marine sciences to ensure sustained growth of human capacity in marine science in South Africa – aligning closely with the current DST Research and Development strategies and the Operation Phakisa Oceans Economy initiative.
- Full Text:
- Date Issued: 2016
- Authors: Ansorge, Isabelle J , Brundrit, Geoff , Brundrit, Jean , Dorrington, Rosemary A , Fawcett, Sarah , Gammon, David , Henry, Tahlia , Hermes, Juliet , Hölscher, Beate , d’Hotman, Jethan , Meiklejohn, Ian , Morris, Tammy , Pinto, Izidine , Du Plessis, Marcel , Roman, Raymond , Saunders, Clinton , Shabangu, Fannie W , De Vos, Marc , Walker, David R , Louw, Gavin
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65539 , vital:28808 , https://doi.org/10.17159/sajs.2016/a0171
- Description: publisher version , From Introduction: Marine science is a highly competitive environment. The need to improve the cohort of South African postgraduates, who would be recognised both nationally and internationally for their scientific excellence, is crucial. It is possible to attract students early on in their careers to this discipline via cutting-edge science, technology and unique field experiences. Through the engagement of students with real-life experiences such as SEAmester, universities supporting marine science postgraduate degree programmes can attract a sustainable throughput of numerically proficient students. By achieving a more quantitative and experienced input into our postgraduate degree programmes, we will, as a scientific community, greatly improve our long-term capabilities to accurately measure, model and predict the impacts of current climate change scenarios. The short-term goal is to attract and establish a cohort of proficient marine and atmospheric science graduates who will contribute to filling the capacity needs of South African marine science as a whole. The SEAmester programme, by involving researchers from across all the relevant disciplines and tertiary institutions, provides an opportunity to build a network of collaborative teaching within the marine field. In doing so, these researchers will foster and strengthen new and current collaborations between historically white and black universities (Figure 1). The long-term objective of SEAmester is to build critical mass within the marine sciences to ensure sustained growth of human capacity in marine science in South Africa – aligning closely with the current DST Research and Development strategies and the Operation Phakisa Oceans Economy initiative.
- Full Text:
- Date Issued: 2016
Role of agricultural marketing in transforming subsistence agriculture: African Case Study
- Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 1989
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143112 , vital:38202 , https://ageconsearch.umn.edu/record/197714/
- Description: A lack of agricultural marketing facilities is generally seen as one of the major obstacles to agricultural development. However, subsistence producers in southern Africa are influenced by certain exogeneous factors, such as competition from commercial production, the well-developed marketing system, and off-farm employment opportunities in South Africa. This paper studies the effect of the institution of an organized marketing system in Ciskei on the level of agricultural production. This is found to have had no significant effect because the majority of the able-bodied males are working in the metropolitan areas of South Africa. This has resulted in agriculture becoming a part-time supplementary activity for women, old men, and children in the rural areas.
- Full Text:
- Date Issued: 1989
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 1989
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143112 , vital:38202 , https://ageconsearch.umn.edu/record/197714/
- Description: A lack of agricultural marketing facilities is generally seen as one of the major obstacles to agricultural development. However, subsistence producers in southern Africa are influenced by certain exogeneous factors, such as competition from commercial production, the well-developed marketing system, and off-farm employment opportunities in South Africa. This paper studies the effect of the institution of an organized marketing system in Ciskei on the level of agricultural production. This is found to have had no significant effect because the majority of the able-bodied males are working in the metropolitan areas of South Africa. This has resulted in agriculture becoming a part-time supplementary activity for women, old men, and children in the rural areas.
- Full Text:
- Date Issued: 1989
Towards an economic valuation of biodiversity: freshwater ecosystems
- Antrobus, Geoffrey G, Law, Matt
- Authors: Antrobus, Geoffrey G , Law, Matt
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143013 , vital:38185 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.620.4217andrep=rep1andtype=pdf
- Description: The valuation of environmental resources and biodiversity as a whole has become an increasingly necessary topic of research as our understanding of the importance and benefits of the healthy functioning of the environment develops. A major shortcoming of current research is that there has been very little advance in the valuation of freshwater biodiversity. The paper examines the socioeconomic importance of biodiversity and outlines the fundamentals of economic valuation thereof. The difficulties associated with the valuation of freshwater ecosystems are outlined and the results of a study presented to the South African Water Research Commission incorporating resource economics into freshwater quality objectives is described. The valuation of freshwater biodiversity is an important and complicated task that needs close attention in future research.
- Full Text:
- Date Issued: 2005
- Authors: Antrobus, Geoffrey G , Law, Matt
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143013 , vital:38185 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.620.4217andrep=rep1andtype=pdf
- Description: The valuation of environmental resources and biodiversity as a whole has become an increasingly necessary topic of research as our understanding of the importance and benefits of the healthy functioning of the environment develops. A major shortcoming of current research is that there has been very little advance in the valuation of freshwater biodiversity. The paper examines the socioeconomic importance of biodiversity and outlines the fundamentals of economic valuation thereof. The difficulties associated with the valuation of freshwater ecosystems are outlined and the results of a study presented to the South African Water Research Commission incorporating resource economics into freshwater quality objectives is described. The valuation of freshwater biodiversity is an important and complicated task that needs close attention in future research.
- Full Text:
- Date Issued: 2005
The market for commercial farm land in the Eastern Cape Province of South Africa as a means of redistribution:
- Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143024 , vital:38194 , DOI: 10.4314/rosas.v3i1.22991
- Description: The election promise of the majority party in the new South African government was to redistribute 30% of the agricultural land in the hands of Whites within a period of 5 years. Transfers of land in the Eastern Cape Province are examined as a case study. While 60% of the total number of Eastern Cape farms changed hands over 5 years, these constituted only 19% of the surface area. A large proportion of rural transfers were small (less than 5 hectares) peri-urban properties which cannot all be considered as viable farming units. At average prices about R1 to R2 billion would be required to establish new farmers on land with the necessary livestock, machinery and equipment. Resource poor new entrants would need a major state contribution to make initial entry and subsequent survival feasible. To achieve their goal through market transfers the government would need to either substantially lengthen its time horizon or lower its target.
- Full Text:
- Date Issued: 1999
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 1999
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143024 , vital:38194 , DOI: 10.4314/rosas.v3i1.22991
- Description: The election promise of the majority party in the new South African government was to redistribute 30% of the agricultural land in the hands of Whites within a period of 5 years. Transfers of land in the Eastern Cape Province are examined as a case study. While 60% of the total number of Eastern Cape farms changed hands over 5 years, these constituted only 19% of the surface area. A large proportion of rural transfers were small (less than 5 hectares) peri-urban properties which cannot all be considered as viable farming units. At average prices about R1 to R2 billion would be required to establish new farmers on land with the necessary livestock, machinery and equipment. Resource poor new entrants would need a major state contribution to make initial entry and subsequent survival feasible. To achieve their goal through market transfers the government would need to either substantially lengthen its time horizon or lower its target.
- Full Text:
- Date Issued: 1999
The commercial agricultural economy of the East Cape: Die kommersiële landbou-ekonomie van die Oos-Kaap
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143079 , vital:38199 , DOI: 10.1080/03031853.1991.9524228
- Description: The East Cape, and in particular the Smaldeel area, is used to exemplify some of the characteristics and problems of commercial farming over a period of about three decades to serve as a backdrop for the broader theme of normalising South African agriculture. The regional economy is dominated by Port Elizabeth-Uitenhage and East London which account for most of the population and three-fourths of the Gross Geographic Product (GGP). Agriculture accounts for only 10% of GGP, but is one of the most labour intensive sectors in a region with 24% of its population unemployed. The agricultural economy of the region is very diversified, but livestock farming plays the most important part in all areas contributing 72% of gross income. The chief changes which have occured in East Cape farming, as elsewhere, have been the decline in the number of farms and increase in farm size, greater capital investment, increased specialisation and declining employment.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143079 , vital:38199 , DOI: 10.1080/03031853.1991.9524228
- Description: The East Cape, and in particular the Smaldeel area, is used to exemplify some of the characteristics and problems of commercial farming over a period of about three decades to serve as a backdrop for the broader theme of normalising South African agriculture. The regional economy is dominated by Port Elizabeth-Uitenhage and East London which account for most of the population and three-fourths of the Gross Geographic Product (GGP). Agriculture accounts for only 10% of GGP, but is one of the most labour intensive sectors in a region with 24% of its population unemployed. The agricultural economy of the region is very diversified, but livestock farming plays the most important part in all areas contributing 72% of gross income. The chief changes which have occured in East Cape farming, as elsewhere, have been the decline in the number of farms and increase in farm size, greater capital investment, increased specialisation and declining employment.
- Full Text:
- Date Issued: 2010
Promoting entrepreneurship in agriculture in the Eastern Cape:
- Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143067 , vital:38198 , DOI: 10.1080/03031853.1994.9524779
- Description: Selected cases in developing entrepreneurship in small-scale subsistence and commercial agriculture in the Eastern Cape are examined, including the provision of marketing facilities, the training programme of the Africa Cooperative Action Trust (ACAT) in Ciskei, government sponsored irrigation projects and the farmer support programme. An attempt is made to draw general conclusions about the necessary ingredients for successful entrepreneurship and the formulation of proposals for further promoting entrepreneurship in agriculture in South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143067 , vital:38198 , DOI: 10.1080/03031853.1994.9524779
- Description: Selected cases in developing entrepreneurship in small-scale subsistence and commercial agriculture in the Eastern Cape are examined, including the provision of marketing facilities, the training programme of the Africa Cooperative Action Trust (ACAT) in Ciskei, government sponsored irrigation projects and the farmer support programme. An attempt is made to draw general conclusions about the necessary ingredients for successful entrepreneurship and the formulation of proposals for further promoting entrepreneurship in agriculture in South Africa.
- Full Text:
- Date Issued: 2010
The role of processors, wholesalers and retailers in the marketing of food in South Africa:
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143090 , vital:38200 , DOI: 10.1080/03031853.1979.9524558
- Description: The importance of the middlemen of marketing was recently high-lighted with the publication of a thirty item 'food basket' for South Africa. While the producer's share of the foodbasket is usually of chief interest to the farmers of our country and often to agricultural economists, the field of traditional agricultural marketing takes in the whole area from farm gate to consumer's table.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143090 , vital:38200 , DOI: 10.1080/03031853.1979.9524558
- Description: The importance of the middlemen of marketing was recently high-lighted with the publication of a thirty item 'food basket' for South Africa. While the producer's share of the foodbasket is usually of chief interest to the farmers of our country and often to agricultural economists, the field of traditional agricultural marketing takes in the whole area from farm gate to consumer's table.
- Full Text:
- Date Issued: 2010
Problems in rural transformation in South Africa specifically in the land reform arena:
- Antrobus, Geoffrey G, Fraser, Gavin C G, Tapson, D R
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G , Tapson, D R
- Date: 1998
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143035 , vital:38195 , https://www.infona.pl/resource/bwmeta1.element.agro-article-dc77672d-7269-4641-bf99-605eaa5fe369
- Description: Problems in rural transformation in South Africa specifically in the land reform arena
- Full Text:
- Date Issued: 1998
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G , Tapson, D R
- Date: 1998
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143035 , vital:38195 , https://www.infona.pl/resource/bwmeta1.element.agro-article-dc77672d-7269-4641-bf99-605eaa5fe369
- Description: Problems in rural transformation in South Africa specifically in the land reform arena
- Full Text:
- Date Issued: 1998
Farm labour in the Eastern Cape, 1950-1973:
- Authors: Antrobus, Geoffrey G
- Date: 1976
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142850 , vital:38123 , http://opensaldru.uct.ac.za/bitstream/handle/11090/465/1976_antrobus_sflcp20.pdf?sequence=1
- Description: The purpose of this paper is to, survey the farm labour conditions in the Eastern Cape over approximately two decades and to note some of the conditions of service and the attitudes of employers, and the changes which have occurred in employment and wages paid. The main source for the latter period, and in particular 1973, is a farm labour survey conducted in conjunction with E.A. Thomson in the Eastern Cape. The survey relied entirely on the willingness of members of farm study groups and Farmers' Associations as well as interested individuals for its completion. Of the approximately 1020 pre-coded questionnaires which were posted to farmers throughout the Eastern Cape in June 1973, 303 were returned of which 299 were suitable for analysis.
- Full Text:
- Date Issued: 1976
- Authors: Antrobus, Geoffrey G
- Date: 1976
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142850 , vital:38123 , http://opensaldru.uct.ac.za/bitstream/handle/11090/465/1976_antrobus_sflcp20.pdf?sequence=1
- Description: The purpose of this paper is to, survey the farm labour conditions in the Eastern Cape over approximately two decades and to note some of the conditions of service and the attitudes of employers, and the changes which have occurred in employment and wages paid. The main source for the latter period, and in particular 1973, is a farm labour survey conducted in conjunction with E.A. Thomson in the Eastern Cape. The survey relied entirely on the willingness of members of farm study groups and Farmers' Associations as well as interested individuals for its completion. Of the approximately 1020 pre-coded questionnaires which were posted to farmers throughout the Eastern Cape in June 1973, 303 were returned of which 299 were suitable for analysis.
- Full Text:
- Date Issued: 1976
The effect of structure on the electrochemical properties of 14 marine pyrroloquinoline metabolites
- Antunes, Edith M, Maree, Suzanne E, Nyokong, Tebello, Davies-Coleman, Mike T, Maree, M David
- Authors: Antunes, Edith M , Maree, Suzanne E , Nyokong, Tebello , Davies-Coleman, Mike T , Maree, M David
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286126 , vital:56242 , xlink:href="https://doi.org/10.3184/030823405775146915"
- Description: The electrochemical properties of 14 structurally related pyrroloquinoline metabolites (compounds 1–14) isolated from marine sponges were studied in pH-varied experiments using cyclic and square wave voltammetry. In general both substitution patterns and pH were observed to influence the reduction potentials of these molecules.
- Full Text:
- Date Issued: 2005
- Authors: Antunes, Edith M , Maree, Suzanne E , Nyokong, Tebello , Davies-Coleman, Mike T , Maree, M David
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/286126 , vital:56242 , xlink:href="https://doi.org/10.3184/030823405775146915"
- Description: The electrochemical properties of 14 structurally related pyrroloquinoline metabolites (compounds 1–14) isolated from marine sponges were studied in pH-varied experiments using cyclic and square wave voltammetry. In general both substitution patterns and pH were observed to influence the reduction potentials of these molecules.
- Full Text:
- Date Issued: 2005