Hsp90 binds directly to fibronectin (FN) and inhibition reduces the extracellular fibronectin matrix in breast cancer cells
- Hunter, Morgan C, O’Hagan, Kyle L, Kenyon, Amy, Dhanani, Karim C H, Prinsloo, Earl, Edkins, Adrienne L
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431143 , vital:72748 , xlink:href="https://doi.org/10.1371/journal.pone.0086842"
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells. Further analysis showed direct binding of Hsp90 to FN using an in vitro co-immunoprecipitation assay, a solid phase binding assay and surface plasmon resonance (SPR) spectroscopy. Confocal microscopy showed regions of co-localisation of Hsp90 and FN in breast cancer cell lines. Exogenous Hsp90β was shown to increase the formation of extracellular FN matrix in the Hs578T cell line, whilst knockdown or inhibition of Hsp90 led to a reduction in the levels of both soluble and insoluble FN and could be partially rescued by addition of exogenous Hsp90β. Treatment of cells with novobiocin led to internalization of FN into vesicles that were positive for the presence of the lysosomal marker, LAMP-1. Taken together, the direct interaction between FN and Hsp90, as well as the decreased levels of both soluble and insoluble FN upon Hsp90 inhibition or knockdown, suggested that FN may be a new client protein for Hsp90 and that Hsp90 was involved in FN matrix assembly and/or stability. The identification of FN as a putative client protein of Hsp90 suggests a role for Hsp90 in FN matrix stability, which is important for a number of fundamental cellular processes including embryogenesis, wound healing, cell migration and metastasis.
- Full Text:
- Date Issued: 2014
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431143 , vital:72748 , xlink:href="https://doi.org/10.1371/journal.pone.0086842"
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells. Further analysis showed direct binding of Hsp90 to FN using an in vitro co-immunoprecipitation assay, a solid phase binding assay and surface plasmon resonance (SPR) spectroscopy. Confocal microscopy showed regions of co-localisation of Hsp90 and FN in breast cancer cell lines. Exogenous Hsp90β was shown to increase the formation of extracellular FN matrix in the Hs578T cell line, whilst knockdown or inhibition of Hsp90 led to a reduction in the levels of both soluble and insoluble FN and could be partially rescued by addition of exogenous Hsp90β. Treatment of cells with novobiocin led to internalization of FN into vesicles that were positive for the presence of the lysosomal marker, LAMP-1. Taken together, the direct interaction between FN and Hsp90, as well as the decreased levels of both soluble and insoluble FN upon Hsp90 inhibition or knockdown, suggested that FN may be a new client protein for Hsp90 and that Hsp90 was involved in FN matrix assembly and/or stability. The identification of FN as a putative client protein of Hsp90 suggests a role for Hsp90 in FN matrix stability, which is important for a number of fundamental cellular processes including embryogenesis, wound healing, cell migration and metastasis.
- Full Text:
- Date Issued: 2014
Hsp90 binds directly to fibronectin (FN) and inhibition reduces the extracellular fibronectin matrix in breast cancer cells:
- Hunter, Morgan C, O’Hagan, Kyle L, Kenyon, Amy, Dhanani, Karim C H, Prinsloo, Earl, Edkins, Adrienne L
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164841 , vital:41177 , DOI: 10.1371/journal.pone.0086842
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells.
- Full Text:
- Date Issued: 2014
- Authors: Hunter, Morgan C , O’Hagan, Kyle L , Kenyon, Amy , Dhanani, Karim C H , Prinsloo, Earl , Edkins, Adrienne L
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164841 , vital:41177 , DOI: 10.1371/journal.pone.0086842
- Description: Heat shock protein 90 (Hsp90) has been identified in the extracellular space and has been shown to chaperone a finite number of extracellular proteins involved in cell migration and invasion. We used chemical cross-linking and immunoprecipitation followed by tandem mass spectrometry (MS/MS) to isolate a complex containing Hsp90 and the matrix protein fibronectin (FN) from breast cancer cells.
- Full Text:
- Date Issued: 2014
Human perception of the measurement of a network attack taxonomy in near real-time
- Van Heerden, Renier, Malan, Mercia M, Mouton, Francois, Irwin, Barry V W
- Authors: Van Heerden, Renier , Malan, Mercia M , Mouton, Francois , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429924 , vital:72652 , https://doi.org/10.1007/978-3-662-44208-1_23
- Description: This paper investigates how the measurement of a network attack taxonomy can be related to human perception. Network attacks do not have a time limitation, but the earlier its detected, the more damage can be prevented and the more preventative actions can be taken. This paper evaluate how elements of network attacks can be measured in near real-time(60 seconds). The taxonomy we use was developed by van Heerden et al (2012) with over 100 classes. These classes present the attack and defenders point of view. The degree to which each class can be quantified or measured is determined by investigating the accuracy of various assessment methods. We classify each class as either defined, high, low or not quantifiable. For example, it may not be possible to determine the instigator of an attack (Aggressor), but only that the attack has been launched by a Hacker (Actor). Some classes can only be quantified with a low confidence or not at all in a sort (near real-time) time. The IP address of an attack can easily be faked thus reducing the confidence in the information obtained from it, and thus determining the origin of an attack with a low confidence. This determination itself is subjective. All the evaluations of the classes in this paper is subjective, but due to the very basic grouping (High, Low or Not Quantifiable) a subjective value can be used. The complexity of the taxonomy can be significantly reduced if classes with only a high perceptive accuracy is used.
- Full Text:
- Date Issued: 2014
- Authors: Van Heerden, Renier , Malan, Mercia M , Mouton, Francois , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429924 , vital:72652 , https://doi.org/10.1007/978-3-662-44208-1_23
- Description: This paper investigates how the measurement of a network attack taxonomy can be related to human perception. Network attacks do not have a time limitation, but the earlier its detected, the more damage can be prevented and the more preventative actions can be taken. This paper evaluate how elements of network attacks can be measured in near real-time(60 seconds). The taxonomy we use was developed by van Heerden et al (2012) with over 100 classes. These classes present the attack and defenders point of view. The degree to which each class can be quantified or measured is determined by investigating the accuracy of various assessment methods. We classify each class as either defined, high, low or not quantifiable. For example, it may not be possible to determine the instigator of an attack (Aggressor), but only that the attack has been launched by a Hacker (Actor). Some classes can only be quantified with a low confidence or not at all in a sort (near real-time) time. The IP address of an attack can easily be faked thus reducing the confidence in the information obtained from it, and thus determining the origin of an attack with a low confidence. This determination itself is subjective. All the evaluations of the classes in this paper is subjective, but due to the very basic grouping (High, Low or Not Quantifiable) a subjective value can be used. The complexity of the taxonomy can be significantly reduced if classes with only a high perceptive accuracy is used.
- Full Text:
- Date Issued: 2014
Hyperbenthic and pelagic predators regulate alternate key planktonic copepods in shallow temperate estuaries
- Wasserman, Ryan J, Vink, Tim J F, Kramer, Rachel, Froneman, P William
- Authors: Wasserman, Ryan J , Vink, Tim J F , Kramer, Rachel , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68224 , vital:29220 , https://doi.org/10.1071/MF13233
- Description: Publisher version , Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.
- Full Text: false
- Date Issued: 2014
- Authors: Wasserman, Ryan J , Vink, Tim J F , Kramer, Rachel , Froneman, P William
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68224 , vital:29220 , https://doi.org/10.1071/MF13233
- Description: Publisher version , Although predation has been identified as an important community driver, the role of predator diversity in structuring estuarine zooplankton has not been assessed. As such, we investigated the effects of two different zooplanktivorous fish species on the estuarine zooplankton community during a 12-day mesocosm study. Three experimental treatments were established, whereby natural zooplankton communities were subject to either (1) no predatory pressure, (2) predation by a pelagic predator (Monodactylus falciformis) or (3) predation by a hyper-benthic predator (Glossogobius callidus). The pelagic feeding M. falciformis fed largely on the numerically dominant mid-water copepod species, Paracartia longipatella. In contrast, the hyper-benthic fish had a greater predatory impact on the less numerically dominant copepod, Pseudodiaptomus hessei, which demonstrates strong diel vertical migration. Variations in prey-population regulation are ascribed to the distinct behavioural differences of the predators, and mediated by the differences in behaviour of the copepod species.
- Full Text: false
- Date Issued: 2014
Improved l-cysteine electrocatalysis through a sequential drop dry technique using multi-walled carbon nanotubes and cobalt tetraaminophthalocyanine conjugates
- Nyoni, Stephen, Mugadza, Tawanda, Nyokong, Tebello
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193813 , vital:45398 , xlink:href="https://doi.org/10.1016/j.electacta.2013.10.023"
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface.
- Full Text:
- Date Issued: 2014
- Authors: Nyoni, Stephen , Mugadza, Tawanda , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193813 , vital:45398 , xlink:href="https://doi.org/10.1016/j.electacta.2013.10.023"
- Description: Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for characterization of a glassy carbon electrode modified with multi-walled carbon nanotubes (MWCNTs)–cobalt tetraaminophthalocyanine (CoTAPc) mixture or sequential drop dry modification technique whereby the MWCNTs are first placed on to the electrode followed by CoTAPc. The sequential drop dry CoTAPc–MWCNTs modified surface gave better catalytic responses with a catalytic rate constant of 2.2 × 105 M−1 s−1, apparent electron transfer rate constant of 0.073 cm s−1, and a limit of detection of 2.8 × 10−7 M. Scanning electrochemical microscopy (SECM) surface characterization (topography and reactivity) further gave proof the better catalytic perfomance of the sequential drop dry CoTAPc–MWCNTs modified surface.
- Full Text:
- Date Issued: 2014
Incorporating surrogate species and seascape connectivity to improve marine conservation outcomes
- Olds, Andrew D, Connolly, Rod M, Pitt, Kylie A, Maxwell, Paul S, Aswani, Shankar, Albert, Simon
- Authors: Olds, Andrew D , Connolly, Rod M , Pitt, Kylie A , Maxwell, Paul S , Aswani, Shankar , Albert, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124722 , vital:35655 , https://doi.10.1111/cobi.12242
- Description: Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species-based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections.
- Full Text:
- Date Issued: 2014
- Authors: Olds, Andrew D , Connolly, Rod M , Pitt, Kylie A , Maxwell, Paul S , Aswani, Shankar , Albert, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124722 , vital:35655 , https://doi.10.1111/cobi.12242
- Description: Conservation focuses on maintaining biodiversity and ecosystem functioning, but gaps in our knowledge of species biology and ecological processes often impede progress. For this reason, focal species and habitats are used as surrogates for multispecies conservation, but species-based approaches are not widely adopted in marine ecosystems. Reserves in the Solomon Islands were designed on the basis of local ecological knowledge to conserve bumphead parrotfish (Bolbometopon muricatum) and to protect food security and ecosystem functioning. Bumphead parrotfish are an iconic threatened species and may be a useful surrogate for multispecies conservation. They move across tropical seascapes throughout their life history, in a pattern of habitat use that is shared with many other species. We examined their value as a conservation surrogate and assessed the importance of seascape connectivity (i.e., the physical connectedness of patches in the seascape) among reefs, mangroves, and seagrass to marine reserve performance. Reserves were designed for bumphead parrotfish, but also enhanced the abundance of other species. Integration of local ecological knowledge and seascape connectivity enhanced the abundance of 17 other harvested fish species in local reserves. This result has important implications for ecosystem functioning and local villagers because many of these species perform important ecological processes and provide the foundation for extensive subsistence fisheries. Our findings suggest greater success in maintaining and restoring marine ecosystems may be achieved when they are managed to conserve surrogate species and preserve functional seascape connections.
- Full Text:
- Date Issued: 2014
Indigenous People’s Detection of Rapid Ecological Change
- Lauer, Matthew, Aswani, Shankar
- Authors: Lauer, Matthew , Aswani, Shankar
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124811 , vital:35699 , https://doi.10.1111/cobi.12250
- Description: When sudden catastrophic events occur, it becomes critical for coastal communities to detect and respond to environmental transformations because failure to do so may undermine overall ecosystem resilience and threaten people’s livelihoods. We therefore asked how capable of detecting rapid ecological change following massive environmental disruptions local, indigenous people are. We assessed the direction and periodicity of experimental learning of people in the Western Solomon Islands after a tsunami in 2007. We compared the results of marine science surveys with local ecological knowledge of the benthos across 3 affected villages and 3 periods before and after the tsunami. We sought to determine how people recognize biophysical changes in the environment before and after catastrophic events such as earthquakes and tsunamis and whether people have the ability to detect ecological changes over short time scales or need longer time scales to recognize changes. Indigenous people were able to detect changes in the benthos over time. Detection levels differed between marine science surveys and local ecological knowledge sources over time, but overall patterns of statistically significant detection of change were evident for various habitats. Our findings have implications for marine conservation, coastal management policies, and disaster-relief efforts because when people are able to detect ecological changes, this, in turn, affects how they exploit and manage their marine resources.
- Full Text:
- Date Issued: 2014
- Authors: Lauer, Matthew , Aswani, Shankar
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124811 , vital:35699 , https://doi.10.1111/cobi.12250
- Description: When sudden catastrophic events occur, it becomes critical for coastal communities to detect and respond to environmental transformations because failure to do so may undermine overall ecosystem resilience and threaten people’s livelihoods. We therefore asked how capable of detecting rapid ecological change following massive environmental disruptions local, indigenous people are. We assessed the direction and periodicity of experimental learning of people in the Western Solomon Islands after a tsunami in 2007. We compared the results of marine science surveys with local ecological knowledge of the benthos across 3 affected villages and 3 periods before and after the tsunami. We sought to determine how people recognize biophysical changes in the environment before and after catastrophic events such as earthquakes and tsunamis and whether people have the ability to detect ecological changes over short time scales or need longer time scales to recognize changes. Indigenous people were able to detect changes in the benthos over time. Detection levels differed between marine science surveys and local ecological knowledge sources over time, but overall patterns of statistically significant detection of change were evident for various habitats. Our findings have implications for marine conservation, coastal management policies, and disaster-relief efforts because when people are able to detect ecological changes, this, in turn, affects how they exploit and manage their marine resources.
- Full Text:
- Date Issued: 2014
Indium phthalocyanine–CdSe/ZnS quantum dots nanocomposites showing size dependent and near ideal optical limiting behaviour
- Sanusi, Kayode, Nyokong, Tebello
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189921 , vital:44947 , xlink:href="https://doi.org/10.1016/j.optmat.2014.09.021"
- Description: Indium phthalocyanine–CdSe/ZnS quantum dots (QDs) nanocomposites (InPc–CdSe/ZnS) of three sizes (5.57, 8.12 and 8.75 nm) were synthesized according to known procedures. The particle size of the CdSe/ZnS QDs alone are 3.95, 6.02, and 6.66 nm, and are denoted as QD1, QD2 and QD3 respectively. The nonlinear absorption (NLA) properties of the nanoconjugates (InPc–CdSe/ZnS) were investigated with nanosecond laser radiation at 532 nm wavelength. Enhanced NLA properties compared to the InPc alone were observed in the conjugates. The NLA was found to increase with the size of the CdSe/ZnS particles attached to the phthalocyanine. The observed increase was due to the availability of more free-carrier ions in the larger QDs, thus giving rise to the enhanced free-carrier absorption. The measured free-carrier absorption cross-sections (σFCA) are 1.10, 1.65 and 1.95 (×10−19 cm2) for InPc-QD1, InPc-QD2 and InPc-QD3 respectively. The nanoconjugates (InPc–CdSe/ZnS) showed a much lower threshold for optical limiting together with a much lower transmission at high fluences, than the previously reported nanocomposite limiters.
- Full Text:
- Date Issued: 2014
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189921 , vital:44947 , xlink:href="https://doi.org/10.1016/j.optmat.2014.09.021"
- Description: Indium phthalocyanine–CdSe/ZnS quantum dots (QDs) nanocomposites (InPc–CdSe/ZnS) of three sizes (5.57, 8.12 and 8.75 nm) were synthesized according to known procedures. The particle size of the CdSe/ZnS QDs alone are 3.95, 6.02, and 6.66 nm, and are denoted as QD1, QD2 and QD3 respectively. The nonlinear absorption (NLA) properties of the nanoconjugates (InPc–CdSe/ZnS) were investigated with nanosecond laser radiation at 532 nm wavelength. Enhanced NLA properties compared to the InPc alone were observed in the conjugates. The NLA was found to increase with the size of the CdSe/ZnS particles attached to the phthalocyanine. The observed increase was due to the availability of more free-carrier ions in the larger QDs, thus giving rise to the enhanced free-carrier absorption. The measured free-carrier absorption cross-sections (σFCA) are 1.10, 1.65 and 1.95 (×10−19 cm2) for InPc-QD1, InPc-QD2 and InPc-QD3 respectively. The nanoconjugates (InPc–CdSe/ZnS) showed a much lower threshold for optical limiting together with a much lower transmission at high fluences, than the previously reported nanocomposite limiters.
- Full Text:
- Date Issued: 2014
Interactive efficacies of Elephantorrhiza elephantina and Pentanisia prunelloides extracts and isolated compounds against gastrointestinal bacteria
- Mpofu, Smart J, Olivier, D K, Krause, Rui W M, Ndinteh, Derek T, Van Vuuren, S
- Authors: Mpofu, Smart J , Olivier, D K , Krause, Rui W M , Ndinteh, Derek T , Van Vuuren, S
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124122 , vital:35552 , https://doi.org/10.1016/j.sajb.2014.07.002
- Description: Elephantorrhiza elephantina (Burch.) Skeels (Fabaceae) and Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) are two medicinal plants used extensively in southern Africa to treat various ailments. Often, decoctions and infusions from these two plants are used in combination specifically for stomach ailments. The antimicrobial activities of the methanol and aqueous extracts of the rhizomes of the two plants, as well as the two active ingredients from the plants [(−)-epicatechin and palmitic acid] have been determined apart and in combination against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739) and Bacillus cereus (ATCC 11778). The minimum inhibitory concentration (MIC) values for the aqueous (0.50–16.00 mg/mL) and methanol (0.20–16.00 mg/mL) extracts independently demonstrated varied efficacies depending on the pathogen of study. When the two plants were combined in 1:1 ratios, synergistic to additive interactions (ΣFIC values 0.19–1.00) were noted. Efficacy for the two major compounds ranged between 0.13–0.63 mg/mL and mainly synergistic interactions were noted against E. faecalis and E. coli. The predominantly synergistic interactions noted between E. elephantina and P. prunelloides and major compounds, when tested in various ratios against these pathogens, provide some validation as to the traditional use of these two plants to treat bacterial gastrointestinal infections.
- Full Text:
- Date Issued: 2014
- Authors: Mpofu, Smart J , Olivier, D K , Krause, Rui W M , Ndinteh, Derek T , Van Vuuren, S
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124122 , vital:35552 , https://doi.org/10.1016/j.sajb.2014.07.002
- Description: Elephantorrhiza elephantina (Burch.) Skeels (Fabaceae) and Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) are two medicinal plants used extensively in southern Africa to treat various ailments. Often, decoctions and infusions from these two plants are used in combination specifically for stomach ailments. The antimicrobial activities of the methanol and aqueous extracts of the rhizomes of the two plants, as well as the two active ingredients from the plants [(−)-epicatechin and palmitic acid] have been determined apart and in combination against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739) and Bacillus cereus (ATCC 11778). The minimum inhibitory concentration (MIC) values for the aqueous (0.50–16.00 mg/mL) and methanol (0.20–16.00 mg/mL) extracts independently demonstrated varied efficacies depending on the pathogen of study. When the two plants were combined in 1:1 ratios, synergistic to additive interactions (ΣFIC values 0.19–1.00) were noted. Efficacy for the two major compounds ranged between 0.13–0.63 mg/mL and mainly synergistic interactions were noted against E. faecalis and E. coli. The predominantly synergistic interactions noted between E. elephantina and P. prunelloides and major compounds, when tested in various ratios against these pathogens, provide some validation as to the traditional use of these two plants to treat bacterial gastrointestinal infections.
- Full Text:
- Date Issued: 2014
Invasive alien species as drivers in socio-ecological systems: Local adaptations towards use of Lantana in Southern India
- Kannan, Ramesh, Shackleton, Charlie M, Shaanker, Ramanan U
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180932 , vital:43671 , xlink:href="https://doi.org/10.1007/s10668-013-9500-y"
- Description: Lantana camara. L (hereafter Lantana) was first introduced by the British into India in 1807 as an ornamental plant. Since then the species has spread across the length and breadth of the country. Attempts to control Lantana in India have not been successful. In this study, we analysed the use of Lantana by local communities in southern India and identified the possible causes and consequences of its use through the use of a household survey of the socio-economic profile of the user and nonuser households and an analysis of the ecological history of the communities. Communities have been using Lantana for over 25–30 years and apparently such use was not prompted by external agencies. The characteristics of user and nonuser households were similar, except that Lantana users were more literate and had a greater number of occupations per household than nonusers. Per capita income was similar between user and nonuser groups. For nonuser groups, their main income sources were from trading (44 %), wage labour (32 %) and forest resources (23 %). In contrast, the Lantana user groups substituted their loss of income from forest resources (7 %) by income from Lantana (46 %). The ecological history revealed that Lantana was adopted as a resource at a time when it was increasing in the landscape and traditional bamboo resources were in decline because of overuse by commercial enterprises and mast flowering. This change in ecological resource availability prompted a major shift in livelihoods for some in the area.
- Full Text:
- Date Issued: 2014
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180932 , vital:43671 , xlink:href="https://doi.org/10.1007/s10668-013-9500-y"
- Description: Lantana camara. L (hereafter Lantana) was first introduced by the British into India in 1807 as an ornamental plant. Since then the species has spread across the length and breadth of the country. Attempts to control Lantana in India have not been successful. In this study, we analysed the use of Lantana by local communities in southern India and identified the possible causes and consequences of its use through the use of a household survey of the socio-economic profile of the user and nonuser households and an analysis of the ecological history of the communities. Communities have been using Lantana for over 25–30 years and apparently such use was not prompted by external agencies. The characteristics of user and nonuser households were similar, except that Lantana users were more literate and had a greater number of occupations per household than nonusers. Per capita income was similar between user and nonuser groups. For nonuser groups, their main income sources were from trading (44 %), wage labour (32 %) and forest resources (23 %). In contrast, the Lantana user groups substituted their loss of income from forest resources (7 %) by income from Lantana (46 %). The ecological history revealed that Lantana was adopted as a resource at a time when it was increasing in the landscape and traditional bamboo resources were in decline because of overuse by commercial enterprises and mast flowering. This change in ecological resource availability prompted a major shift in livelihoods for some in the area.
- Full Text:
- Date Issued: 2014
Investigating coral reef ethnobiology in the western Solomon Islands for enhancing livelihood resilience:
- Authors: Aswani, Shankar
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145425 , vital:38437 , DOI: 10.15286/jps.123.3.237-276
- Description: Coral reefs are of great socio-economic and cultural importance for many coastal communities across the tropics, yet little is known about people's local classifications and their social and ecological relationships with these habitats. In the case of island peoples, coral reefs are more than just resource exploitation areas; they are also géomorphologie features that allow or bar people from navigating, markers that define property rights of the seascape in relation to other coastal and terrestrial habitats, and cultural and historical features that embody tribal identity and ideology. Building upon over two decades of research, this paper uses published and unpublished data to describe people's ecological and socio-economic relationships with coral reefs in two extensive lagoon ecosystems in the Western Solomon Islands.
- Full Text:
- Date Issued: 2014
- Authors: Aswani, Shankar
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145425 , vital:38437 , DOI: 10.15286/jps.123.3.237-276
- Description: Coral reefs are of great socio-economic and cultural importance for many coastal communities across the tropics, yet little is known about people's local classifications and their social and ecological relationships with these habitats. In the case of island peoples, coral reefs are more than just resource exploitation areas; they are also géomorphologie features that allow or bar people from navigating, markers that define property rights of the seascape in relation to other coastal and terrestrial habitats, and cultural and historical features that embody tribal identity and ideology. Building upon over two decades of research, this paper uses published and unpublished data to describe people's ecological and socio-economic relationships with coral reefs in two extensive lagoon ecosystems in the Western Solomon Islands.
- Full Text:
- Date Issued: 2014
Investigating the chaperone properties of a novel heat shock protein, Hsp70. c, from Trypanosoma brucei
- Burger, Adélle, Ludewig, Michael H, Boshoff, Aileen
- Authors: Burger, Adélle , Ludewig, Michael H , Boshoff, Aileen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431155 , vital:72749 , xlink:href="https://doi.org/10.1155/2014/172582"
- Description: The neglected tropical disease, African Trypanosomiasis, is fatal and has a crippling impact on economic development. Heat shock protein 70 (Hsp70) is an important molecular chaperone that is expressed in response to stress and Hsp40 acts as its co-chaperone. These proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. A novel cytosolic Hsp70, from Trypanosoma brucei, TbHsp70.c, contains an acidic substrate binding domain and lacks the C-terminal EEVD motif.The ability of a cytosolic Hsp40 from Trypanosoma brucei J protein 2, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated.The main objective was to functionally characterize TbHsp70.c to further expand our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed the ability to suppress aggregation of thermolabile MDH and chemically denatured rhodanese. ATPase assays revealed a 2.8-fold stimulation of the ATPase activity of TbHsp70.c by Tbj2. TbHsp70.c and Tbj2 both demonstrated chaperone activity and Tbj2 functions as a co-chaperone of TbHsp70.c.In vivo heat stress experiments indicated upregulation of the expression levels of TbHsp70.c.
- Full Text:
- Date Issued: 2014
- Authors: Burger, Adélle , Ludewig, Michael H , Boshoff, Aileen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431155 , vital:72749 , xlink:href="https://doi.org/10.1155/2014/172582"
- Description: The neglected tropical disease, African Trypanosomiasis, is fatal and has a crippling impact on economic development. Heat shock protein 70 (Hsp70) is an important molecular chaperone that is expressed in response to stress and Hsp40 acts as its co-chaperone. These proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. A novel cytosolic Hsp70, from Trypanosoma brucei, TbHsp70.c, contains an acidic substrate binding domain and lacks the C-terminal EEVD motif.The ability of a cytosolic Hsp40 from Trypanosoma brucei J protein 2, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated.The main objective was to functionally characterize TbHsp70.c to further expand our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed the ability to suppress aggregation of thermolabile MDH and chemically denatured rhodanese. ATPase assays revealed a 2.8-fold stimulation of the ATPase activity of TbHsp70.c by Tbj2. TbHsp70.c and Tbj2 both demonstrated chaperone activity and Tbj2 functions as a co-chaperone of TbHsp70.c.In vivo heat stress experiments indicated upregulation of the expression levels of TbHsp70.c.
- Full Text:
- Date Issued: 2014
Investigations of growth metrics and δ15N values of water hyacinth (Eichhornia crassipes,(Mart.) Solms-Laub) in relation to biological control
- Authors: Hill, Jaclyn M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444758 , vital:74265 , https://doi.org/10.1016/j.aquabot.2013.12.001
- Description: The success of biological control for Eichhornia crassipes (Mart) Solms-Laub has been varied, with failure attributed to various factors including increased eutrophication in freshwater systems. Studies have shown that high N-loads are associated with enriched δ15N values of aquatic biota. Stable isotope analyses may help to assess the nutrient status of invaded ecosystems and predict the success of classical biological control. A combination of controlled greenhouse experiments and in situ observations were used to quantify the δ15N equilibration rate of E. crassipes leaf tissue (i.e. the time span of the information on environmental N-loading), confirm the ability of plant tissue to reflect ecosystem N-loading and to compare standard water hyacinth growth metrics with δ15N and C/N ratios to evaluate how well they described eutrophication. Using both δ15N values and C/N ratios, it was possible to clearly distinguish between manure, fertilizer and control regimes and plant tissue provided information on ecosystem N loading over approximately 16 days.
- Full Text:
- Date Issued: 2014
- Authors: Hill, Jaclyn M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444758 , vital:74265 , https://doi.org/10.1016/j.aquabot.2013.12.001
- Description: The success of biological control for Eichhornia crassipes (Mart) Solms-Laub has been varied, with failure attributed to various factors including increased eutrophication in freshwater systems. Studies have shown that high N-loads are associated with enriched δ15N values of aquatic biota. Stable isotope analyses may help to assess the nutrient status of invaded ecosystems and predict the success of classical biological control. A combination of controlled greenhouse experiments and in situ observations were used to quantify the δ15N equilibration rate of E. crassipes leaf tissue (i.e. the time span of the information on environmental N-loading), confirm the ability of plant tissue to reflect ecosystem N-loading and to compare standard water hyacinth growth metrics with δ15N and C/N ratios to evaluate how well they described eutrophication. Using both δ15N values and C/N ratios, it was possible to clearly distinguish between manure, fertilizer and control regimes and plant tissue provided information on ecosystem N loading over approximately 16 days.
- Full Text:
- Date Issued: 2014
Isn’t it time to start thinking about ‘developing’ academic developers in a more systematic way?
- Quinn, Lynn, Vorster, Jo-Anne
- Authors: Quinn, Lynn , Vorster, Jo-Anne
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66546 , vital:28961 , https://doi.org/10.1080/1360144X.2013.879719
- Description: publisher version , There is no defined route to becoming an academic developer. The research on pathways into the field (e.g. Kensington-Miller, Brailsford, and Gossman, 2012; McDonald, 2010; McDonald and Stockley, 2008) shows that in most cases ‘serendipity and chance played a role’ (McDonald, 2010, p. 40). Moreover, induction into academic development (AD) is often ad hoc, haphazard, and informal. Due to the changing higher education (HE) context, the field has grown exponentially and in many countries now plays a central role in institutions. This has generated increased demand for knowledgeable and competent developers that are able to contribute towards solving some vexing problems in contemporary HE. Current recruitment and induction processes of new developers do not necessarily meet this demand. In light of the above, we pose the question: given the changing context of HE and the field of AD, is it not time for us to induct newcomers into the field more systematically? As Kensington-Miller et al. (2012) suggest, we should not leave the induction of the next generation of developers to chance. We suggest that one way of ensuring appropriate induction is through a formal course for developers. Difficulties for newcomers to the field are illustrated by Kensington-Miller et al. (2012) when they report seeking ‘top tips’ at a HERDSA conference. We do not dismiss informal learning at conferences or the role of mentoring, coaching, apprenticeship, and so on, in inducting developers, nor do we minimise the benefits of relatively structured processes such as fellowship programmes, workshops, and postgraduate qualifications in related fields. However, these ways of induction may not offer novices the structured and systematic developmental opportunities needed to become developers able to fulfil varied, complex, and sometimes contradictory roles.
- Full Text: false
- Date Issued: 2014
- Authors: Quinn, Lynn , Vorster, Jo-Anne
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66546 , vital:28961 , https://doi.org/10.1080/1360144X.2013.879719
- Description: publisher version , There is no defined route to becoming an academic developer. The research on pathways into the field (e.g. Kensington-Miller, Brailsford, and Gossman, 2012; McDonald, 2010; McDonald and Stockley, 2008) shows that in most cases ‘serendipity and chance played a role’ (McDonald, 2010, p. 40). Moreover, induction into academic development (AD) is often ad hoc, haphazard, and informal. Due to the changing higher education (HE) context, the field has grown exponentially and in many countries now plays a central role in institutions. This has generated increased demand for knowledgeable and competent developers that are able to contribute towards solving some vexing problems in contemporary HE. Current recruitment and induction processes of new developers do not necessarily meet this demand. In light of the above, we pose the question: given the changing context of HE and the field of AD, is it not time for us to induct newcomers into the field more systematically? As Kensington-Miller et al. (2012) suggest, we should not leave the induction of the next generation of developers to chance. We suggest that one way of ensuring appropriate induction is through a formal course for developers. Difficulties for newcomers to the field are illustrated by Kensington-Miller et al. (2012) when they report seeking ‘top tips’ at a HERDSA conference. We do not dismiss informal learning at conferences or the role of mentoring, coaching, apprenticeship, and so on, in inducting developers, nor do we minimise the benefits of relatively structured processes such as fellowship programmes, workshops, and postgraduate qualifications in related fields. However, these ways of induction may not offer novices the structured and systematic developmental opportunities needed to become developers able to fulfil varied, complex, and sometimes contradictory roles.
- Full Text: false
- Date Issued: 2014
ISSRs indicate that Chromolaena odorata invading southern Africa originates in Jamaica or Cuba
- Paterson, Iain D, Zachariades, Costas
- Authors: Paterson, Iain D , Zachariades, Costas
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406105 , vital:70239 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.04.005"
- Description: Two biotypes of the invasive alien plant, Chromolaena odorata (L.) R.M. King and Rob. (Asteraceae: Eupatorieae), are recognized in the plant’s introduced distribution. The Asian/West African (A/WA) biotype is present in West and Central Africa, India, Southeast Asia and Oceania, while the southern African (SA) biotype is only present in southern Africa. Biological control using insect natural enemies has been significantly more successful against the A/WA biotype than the SA biotype, suggesting that host plant incompatibility may have resulted in reduced efficacy of biological control agents in southern Africa. Inter-Simple Sequence Repeats (ISSR) were used to identify the origin of the SA biotype as Jamaica or Cuba. The data also confirm that the SA biotype is genetically distinct from the A/WA biotype and that the SA biotype is the result of a separate introduction. Biological control agents for C. odorata in southern Africa should be sourced from Jamaica and Cuba in order to avoid host plant incompatibility problems.
- Full Text:
- Date Issued: 2014
- Authors: Paterson, Iain D , Zachariades, Costas
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406105 , vital:70239 , xlink:href="https://doi.org/10.1016/j.biocontrol.2013.04.005"
- Description: Two biotypes of the invasive alien plant, Chromolaena odorata (L.) R.M. King and Rob. (Asteraceae: Eupatorieae), are recognized in the plant’s introduced distribution. The Asian/West African (A/WA) biotype is present in West and Central Africa, India, Southeast Asia and Oceania, while the southern African (SA) biotype is only present in southern Africa. Biological control using insect natural enemies has been significantly more successful against the A/WA biotype than the SA biotype, suggesting that host plant incompatibility may have resulted in reduced efficacy of biological control agents in southern Africa. Inter-Simple Sequence Repeats (ISSR) were used to identify the origin of the SA biotype as Jamaica or Cuba. The data also confirm that the SA biotype is genetically distinct from the A/WA biotype and that the SA biotype is the result of a separate introduction. Biological control agents for C. odorata in southern Africa should be sourced from Jamaica and Cuba in order to avoid host plant incompatibility problems.
- Full Text:
- Date Issued: 2014
Kalaharituber pfeilii and associated bacterial interactions
- Adeleke, Rasheed, Dames, Joanna F
- Authors: Adeleke, Rasheed , Dames, Joanna F
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440490 , vital:73787 , https://doi.org/10.1016/j.sajb.2013.10.003
- Description: Truffles are generally known to form a mycorrhizal relationship with plants. Kalaharituber pfeilii (Hennings) Trappe and Kagan-Zur is a species of desert truffle that is found in the southern part of Africa. The life cycle of this truffle has not been fully investigated as there are many unconfirmed plant species that have been suggested as potential hosts. Many mycorrhizal associations often involve other role players such as associated bacteria that may influence the establishment of the mycorrhizal formation and function. As part of an effort to understand the life cycle of K. pfeilii, laboratory experiments were conducted to investigate the role of ascocarp associated bacteria. Bacterial isolates obtained from the truffle ascocarps were subjected to microbiological and biochemical tests to determine their potentials as mycorrhizal helper bacteria. Tests conducted included stimulation of mycelial growth in vitro, indole acetic acid (IAA) production and phosphate solubilising. A total of 17 bacterial strains belonging to the Proteobacteria, Firmicutes and Actinobacteria were isolated from the truffle ascocarps and identified with sequence homology and phylogenetic methods. Three of these isolates showed potential to be helper bacteria in at least one of the media tested through the stimulation of mycelial growth. Furthermore, four isolates produced IAA and one was able to solubilise CaHPO3 in vitro. One isolate, identified as a relative of Paenibacillus sp. stimulated mycelial growth on all the media tested. Other bacterial isolates that showed potential stimulation of mycelial growth were identified molecularly as a Bacillus sp. and two strains of Rhizobium sp. This study has contributed to the existing knowledge on the biotic interactions with K. pfeilii which may be useful in further symbiont and re-synthesis investigations.
- Full Text:
- Date Issued: 2014
- Authors: Adeleke, Rasheed , Dames, Joanna F
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440490 , vital:73787 , https://doi.org/10.1016/j.sajb.2013.10.003
- Description: Truffles are generally known to form a mycorrhizal relationship with plants. Kalaharituber pfeilii (Hennings) Trappe and Kagan-Zur is a species of desert truffle that is found in the southern part of Africa. The life cycle of this truffle has not been fully investigated as there are many unconfirmed plant species that have been suggested as potential hosts. Many mycorrhizal associations often involve other role players such as associated bacteria that may influence the establishment of the mycorrhizal formation and function. As part of an effort to understand the life cycle of K. pfeilii, laboratory experiments were conducted to investigate the role of ascocarp associated bacteria. Bacterial isolates obtained from the truffle ascocarps were subjected to microbiological and biochemical tests to determine their potentials as mycorrhizal helper bacteria. Tests conducted included stimulation of mycelial growth in vitro, indole acetic acid (IAA) production and phosphate solubilising. A total of 17 bacterial strains belonging to the Proteobacteria, Firmicutes and Actinobacteria were isolated from the truffle ascocarps and identified with sequence homology and phylogenetic methods. Three of these isolates showed potential to be helper bacteria in at least one of the media tested through the stimulation of mycelial growth. Furthermore, four isolates produced IAA and one was able to solubilise CaHPO3 in vitro. One isolate, identified as a relative of Paenibacillus sp. stimulated mycelial growth on all the media tested. Other bacterial isolates that showed potential stimulation of mycelial growth were identified molecularly as a Bacillus sp. and two strains of Rhizobium sp. This study has contributed to the existing knowledge on the biotic interactions with K. pfeilii which may be useful in further symbiont and re-synthesis investigations.
- Full Text:
- Date Issued: 2014
Liberation movements in power: party and state in southern Africa
- Authors: Helliker, Kirk D
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144688 , vital:38370 , DOI: 10.1080/21528586.2014.960705
- Description: In Liberation movements in power, Roger Southall provides a rich and refined account of political transformation in three ex-settler colonies in southern Africa, namely, South Africa, Namibia and Zimbabwe. In particular, he focuses on their former hegemonic national liberation movements, namely, the African National Congress (ANC) in South Africa, the South West African People’s Organisation (SWAPO) in Namibia and the Zimbabwe African National Union (ZANU) – now ZANU-Patriotic Front (ZANU-PF) – in Zimbabwe, their metamorphism into political parties and party machines, and their ‘capture’ of state power as the dominant political party subsequent to the end of white settler colonialism and the emergence of non-racial democracy. The general conclusion is that democratic ideals and procedures have become subordinated to the dictates of authoritarian restructuring.
- Full Text:
- Date Issued: 2014
- Authors: Helliker, Kirk D
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144688 , vital:38370 , DOI: 10.1080/21528586.2014.960705
- Description: In Liberation movements in power, Roger Southall provides a rich and refined account of political transformation in three ex-settler colonies in southern Africa, namely, South Africa, Namibia and Zimbabwe. In particular, he focuses on their former hegemonic national liberation movements, namely, the African National Congress (ANC) in South Africa, the South West African People’s Organisation (SWAPO) in Namibia and the Zimbabwe African National Union (ZANU) – now ZANU-Patriotic Front (ZANU-PF) – in Zimbabwe, their metamorphism into political parties and party machines, and their ‘capture’ of state power as the dominant political party subsequent to the end of white settler colonialism and the emergence of non-racial democracy. The general conclusion is that democratic ideals and procedures have become subordinated to the dictates of authoritarian restructuring.
- Full Text:
- Date Issued: 2014
Life satisfaction and education in South Africa: Investigating the role of attainment and the likelihood of education as a positional good
- Authors: Botha, Ferdi
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396091 , vital:69149 , xlink:href="https://doi.org/10.1007/s11205-013-0452-2"
- Description: This paper explores various dynamics in the relationship between life satisfaction and education in South Africa using the 2008 National Income Dynamics Survey. The results indicate a strong positive association between educational attainment and individual satisfaction with life, which is true in the overall sample and for men and women. This positive relationship also holds for Black and Coloured individuals, but is insignificant in the Asian and White samples. Evidence indicates that education is a positional good, in that people who have attained more than the mean level of education in their relevant cluster are significantly more satisfied with life compared to those possessing less than the mean education.
- Full Text:
- Date Issued: 2014
- Authors: Botha, Ferdi
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396091 , vital:69149 , xlink:href="https://doi.org/10.1007/s11205-013-0452-2"
- Description: This paper explores various dynamics in the relationship between life satisfaction and education in South Africa using the 2008 National Income Dynamics Survey. The results indicate a strong positive association between educational attainment and individual satisfaction with life, which is true in the overall sample and for men and women. This positive relationship also holds for Black and Coloured individuals, but is insignificant in the Asian and White samples. Evidence indicates that education is a positional good, in that people who have attained more than the mean level of education in their relevant cluster are significantly more satisfied with life compared to those possessing less than the mean education.
- Full Text:
- Date Issued: 2014
Life-history characteristics of an age-validated established invasive African sharptooth catfish, Clarias gariepinus, population in a warm-temperate African impoundment
- Wartenberg, Reece, Weyl, Olaf L F, Booth, Anthony J, Winker, A Henning
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443542 , vital:74130 , https://hdl.handle.net/10520/EJC145790
- Description: It has been suggested that the invasive, omnivorous Clarias garipienus is capable of rapid invasions and long-term persistence in recently inhabited freshwater systems. To test this hypothesis, the life history of the established, extralimital Darlington Dam (33°10'31"S, 25°09'13"E) population was investigated. By counting post-fluorescent mark increments on otoliths from 21 chemically tagged wild fish recaptured 244-537 days later, the deposition of growth zones, comprising alternating opaque and translucent bands, was validated as annual. Examination of sectioned otoliths from 175 fish revealed that the oldest fish, two males of 840 and 1074 mm total length (TL), were 25 years old - 10 years older than previously described for any C. gariepinus population. The oldest female was 885 mm TL and 21 years old. Length-at-age was subsequently described using the von Bertalanffy growth model. Combined-sex growth was best described as Lt = 931.7 ( 1 - exp(-0.15(t +2.43))) mm TL. Total mortality (Z) was calculated using catch curve analysis and the Chapman and Robson estimator to be 0.35/yr. The presence of specimens 15 years and older indicates that these fish established quickly and supports the finding that mortality rates are low, which, in turn, suggests likely long-term population persistence.
- Full Text:
- Date Issued: 2014
- Authors: Wartenberg, Reece , Weyl, Olaf L F , Booth, Anthony J , Winker, A Henning
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443542 , vital:74130 , https://hdl.handle.net/10520/EJC145790
- Description: It has been suggested that the invasive, omnivorous Clarias garipienus is capable of rapid invasions and long-term persistence in recently inhabited freshwater systems. To test this hypothesis, the life history of the established, extralimital Darlington Dam (33°10'31"S, 25°09'13"E) population was investigated. By counting post-fluorescent mark increments on otoliths from 21 chemically tagged wild fish recaptured 244-537 days later, the deposition of growth zones, comprising alternating opaque and translucent bands, was validated as annual. Examination of sectioned otoliths from 175 fish revealed that the oldest fish, two males of 840 and 1074 mm total length (TL), were 25 years old - 10 years older than previously described for any C. gariepinus population. The oldest female was 885 mm TL and 21 years old. Length-at-age was subsequently described using the von Bertalanffy growth model. Combined-sex growth was best described as Lt = 931.7 ( 1 - exp(-0.15(t +2.43))) mm TL. Total mortality (Z) was calculated using catch curve analysis and the Chapman and Robson estimator to be 0.35/yr. The presence of specimens 15 years and older indicates that these fish established quickly and supports the finding that mortality rates are low, which, in turn, suggests likely long-term population persistence.
- Full Text:
- Date Issued: 2014
Losing, using, refusing, cruising: first-generation South African women academics narrate the complexity of marginality
- Idahosa, Grace E, Vincent, Louise
- Authors: Idahosa, Grace E , Vincent, Louise
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141820 , vital:38007 , DOI: 10.1080/10130950.2014.874766
- Description: In this article we ask how senior academic women in South Africa narrate their experience of being ‘outside in’ the teaching machine. Wide research literature documents the gross underrepresentation of women in senior positions in the academy. It has been argued that intertwined sexist, patriarchal and phallocentric knowledges and practices in academic institutions produce various forms of discrimination, inequality, oppression and marginalisation. Academic women report feeling invisible and retreating to the margins so as to avoid victimisation and discrimination. Others have pointed to the tension between the ‘tenure clock’ and ‘biological clock’ as a source of anxiety. However, experiences of academic women are not identical. In the context of studies showing the importance of existing personal and social resources, prior experience and having mentors and role models in the negotiation of inequality and discrimination, we document the narratives of women academics who are the first in their families to graduate with a university degree.
- Full Text:
- Date Issued: 2014
- Authors: Idahosa, Grace E , Vincent, Louise
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141820 , vital:38007 , DOI: 10.1080/10130950.2014.874766
- Description: In this article we ask how senior academic women in South Africa narrate their experience of being ‘outside in’ the teaching machine. Wide research literature documents the gross underrepresentation of women in senior positions in the academy. It has been argued that intertwined sexist, patriarchal and phallocentric knowledges and practices in academic institutions produce various forms of discrimination, inequality, oppression and marginalisation. Academic women report feeling invisible and retreating to the margins so as to avoid victimisation and discrimination. Others have pointed to the tension between the ‘tenure clock’ and ‘biological clock’ as a source of anxiety. However, experiences of academic women are not identical. In the context of studies showing the importance of existing personal and social resources, prior experience and having mentors and role models in the negotiation of inequality and discrimination, we document the narratives of women academics who are the first in their families to graduate with a university degree.
- Full Text:
- Date Issued: 2014