Assessment of taste masking of captopril by ion-exchange resins using electronic gustatory system
- Chikukwa, Mellisa T R, Wesoly, Malgorzata, Korzeniowska, Aleksandra B, Ciosek-Skibinska, Patrycja, Walker, Roderick B, Khamanga, Sandile M M
- Authors: Chikukwa, Mellisa T R , Wesoly, Malgorzata , Korzeniowska, Aleksandra B , Ciosek-Skibinska, Patrycja , Walker, Roderick B , Khamanga, Sandile M M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184710 , vital:44265 , xlink:href="https://doi.org/10.1080/10837450.2019.1687520"
- Description: The objective of the study was to mask the unpleasant taste of captopril (CPT). Taste masking was achieved by complexation of CPT with a basic ion exchange resin, Dowex® 66, using the batch method. Dowex® 66 was used for the adsorption of CPT, and physical and chemical parameters of the CPT resinates complex were evaluated. A central composite design was used to generate the experiments for the manufacture of resinates using different process and formulation variables. In vitro dissolution studies were performed for 2 h in 0.01N HCl (pH 1.6) using USP Apparatus I. The compatibility of CPT and the resin was evaluated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The resinates were evaluated for micromeritic properties and further characterised using FTIR, DSC, and PXRD. Response surface methodology was used to determine the significance of input variables on the CPT content and release. The CPT resin ratio was found to have a significant impact on content of the resinates and on CPT release. The formulations were also studied for taste masking ability by means of an electronic gustatory system – electronic tongue.
- Full Text:
- Authors: Chikukwa, Mellisa T R , Wesoly, Malgorzata , Korzeniowska, Aleksandra B , Ciosek-Skibinska, Patrycja , Walker, Roderick B , Khamanga, Sandile M M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184710 , vital:44265 , xlink:href="https://doi.org/10.1080/10837450.2019.1687520"
- Description: The objective of the study was to mask the unpleasant taste of captopril (CPT). Taste masking was achieved by complexation of CPT with a basic ion exchange resin, Dowex® 66, using the batch method. Dowex® 66 was used for the adsorption of CPT, and physical and chemical parameters of the CPT resinates complex were evaluated. A central composite design was used to generate the experiments for the manufacture of resinates using different process and formulation variables. In vitro dissolution studies were performed for 2 h in 0.01N HCl (pH 1.6) using USP Apparatus I. The compatibility of CPT and the resin was evaluated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The resinates were evaluated for micromeritic properties and further characterised using FTIR, DSC, and PXRD. Response surface methodology was used to determine the significance of input variables on the CPT content and release. The CPT resin ratio was found to have a significant impact on content of the resinates and on CPT release. The formulations were also studied for taste masking ability by means of an electronic gustatory system – electronic tongue.
- Full Text:
Attitudinal difference surveys perpetuate harmful tropes: A comment on Nattrass
- Rosenberg, Eureta, Le Grange, Lesley
- Authors: Rosenberg, Eureta , Le Grange, Lesley
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370129 , vital:66300 , xlink:href="https://doi.org/10.17159/sajs.2020/8469"
- Description: We reply to the article, ‘Why are black South African students less likely to consider studying biological sciences?’, authored by University of Cape Town (UCT) researcher Nicoli Nattrass1 and published in the South African Journal of Science on 27 May 2020. At the time of writing our reply the article had already received sharp criticism from the Black Academic Caucus at UCT and in a statement released on 5 June 2020, the UCT executive distanced itself from the content of the paper, inviting rigorous, respectful review of the published research. Nattrass’ article1 follows two papers published in 2019 by scholars associated with South African universities, both of which were widely denounced for the racist undertones of their content. The first article was authored by Stellenbosch University researchers who reported on low cognitive functioning of coloured women linked to education levels and lifestyles2 ; see comment by Le Grange3 . The second article was co-authored by an adjunct professor at UCT and examined the role of cognitive ability or intelligence on slave exports from Africa4 . These publications gave rise to a broader debate on enduring racism in science and the re-ascendency of race science internationally. In this reply, we focus on the methodology of attitudinal survey used for the study reported by Nattrass (and by many other scientists). There are two lines of argument that we weave together: the quality of the research as reported, and problems inherent to comparative attitudinal survey research (regardless of how well it is executed). It should be noted that the Black Academic Caucus at UCT has also critiqued the research design, identifying many of the points we make here, and they have additionally included a discourse analysis of the paper (circulated via e-mail). To demonstrate how problematic a survey design can be, particularly when it is not rigorously executed, we share data and observations that counter the apparent findings of Nattrass’ study. We then argue that the publication of this research, in this manner, is detrimental to the biodiversity sector in which the tropes being perpetuated, can cause enormous harm. In the process we hope to encourage scientists to be more reflexive about their methodology, and we encourage the South African Journal of Science to publish works that are worthy of the young people of this country - research in which they can recognise themselves, rather than being forced to look at reductionist portrayals, legitimised under the banner of science.
- Full Text:
- Authors: Rosenberg, Eureta , Le Grange, Lesley
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370129 , vital:66300 , xlink:href="https://doi.org/10.17159/sajs.2020/8469"
- Description: We reply to the article, ‘Why are black South African students less likely to consider studying biological sciences?’, authored by University of Cape Town (UCT) researcher Nicoli Nattrass1 and published in the South African Journal of Science on 27 May 2020. At the time of writing our reply the article had already received sharp criticism from the Black Academic Caucus at UCT and in a statement released on 5 June 2020, the UCT executive distanced itself from the content of the paper, inviting rigorous, respectful review of the published research. Nattrass’ article1 follows two papers published in 2019 by scholars associated with South African universities, both of which were widely denounced for the racist undertones of their content. The first article was authored by Stellenbosch University researchers who reported on low cognitive functioning of coloured women linked to education levels and lifestyles2 ; see comment by Le Grange3 . The second article was co-authored by an adjunct professor at UCT and examined the role of cognitive ability or intelligence on slave exports from Africa4 . These publications gave rise to a broader debate on enduring racism in science and the re-ascendency of race science internationally. In this reply, we focus on the methodology of attitudinal survey used for the study reported by Nattrass (and by many other scientists). There are two lines of argument that we weave together: the quality of the research as reported, and problems inherent to comparative attitudinal survey research (regardless of how well it is executed). It should be noted that the Black Academic Caucus at UCT has also critiqued the research design, identifying many of the points we make here, and they have additionally included a discourse analysis of the paper (circulated via e-mail). To demonstrate how problematic a survey design can be, particularly when it is not rigorously executed, we share data and observations that counter the apparent findings of Nattrass’ study. We then argue that the publication of this research, in this manner, is detrimental to the biodiversity sector in which the tropes being perpetuated, can cause enormous harm. In the process we hope to encourage scientists to be more reflexive about their methodology, and we encourage the South African Journal of Science to publish works that are worthy of the young people of this country - research in which they can recognise themselves, rather than being forced to look at reductionist portrayals, legitimised under the banner of science.
- Full Text:
Bacterial degradation of coal discard and geologically weathered coal:
- Olawale, Jacob T, Edeki, Oghenekume G, Cowan, Keith A
- Authors: Olawale, Jacob T , Edeki, Oghenekume G , Cowan, Keith A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/178694 , vital:40097 , https://doi.org/10.1007/s40789-020-00306-3
- Description: The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India.
- Full Text:
- Authors: Olawale, Jacob T , Edeki, Oghenekume G , Cowan, Keith A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/178694 , vital:40097 , https://doi.org/10.1007/s40789-020-00306-3
- Description: The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India.
- Full Text:
Bat species richness and community composition along a mega-transect in the Okavango river basin:
- Weier, Sina M, Keith, Mark, Neef, Götz G, Parker, Daniel M, Taylor, Peter J
- Authors: Weier, Sina M , Keith, Mark , Neef, Götz G , Parker, Daniel M , Taylor, Peter J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149264 , vital:38820 , https://doi.org/10.3390/d12050188
- Description: The Okavango River Basin is a hotspot of bat diversity that requires urgent and adequate protection. To advise future conservation strategies, we investigated the relative importance of a range of potential environmental drivers of bat species richness and functional community composition in the Okavango River Basin. During annual canoe transects along the major rivers, originating in the central Angolan highlands, we recorded more than 25,000 bat echolocation calls from 2015 to 2018. We corrected for possible biases in sampling design and effort.
- Full Text:
- Authors: Weier, Sina M , Keith, Mark , Neef, Götz G , Parker, Daniel M , Taylor, Peter J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149264 , vital:38820 , https://doi.org/10.3390/d12050188
- Description: The Okavango River Basin is a hotspot of bat diversity that requires urgent and adequate protection. To advise future conservation strategies, we investigated the relative importance of a range of potential environmental drivers of bat species richness and functional community composition in the Okavango River Basin. During annual canoe transects along the major rivers, originating in the central Angolan highlands, we recorded more than 25,000 bat echolocation calls from 2015 to 2018. We corrected for possible biases in sampling design and effort.
- Full Text:
Biocompatibility of biomaterials for nanoencapsulation: Current approaches
- Witika, Bwalya A, Makoni, Pedzisai A, Matafwali, Scott K, Chabalenge, Billy, Mwila, Chiluba, Kalungia, Aubrey C, Nkanga, Christian I, Bapolisi, Alain M, Walker, Roderick B
- Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
- Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
- Full Text:
- Authors: Witika, Bwalya A , Makoni, Pedzisai A , Matafwali, Scott K , Chabalenge, Billy , Mwila, Chiluba , Kalungia, Aubrey C , Nkanga, Christian I , Bapolisi, Alain M , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183289 , vital:43939 , xlink:href="https://doi.org/10.3390/nano10091649"
- Description: Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.
- Full Text:
Bioelectrocatalysis and surface analysis of gold coated with nickel oxide/hydroxide and glucose oxidase towards detection of glucose:
- Njoko, Nqobile, Louzada, Marcel, Britton, Jonathan, Khene, Samson M, Nyokong, Tebello, Mashazi, Philani N
- Authors: Njoko, Nqobile , Louzada, Marcel , Britton, Jonathan , Khene, Samson M , Nyokong, Tebello , Mashazi, Philani N
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150071 , vital:38937 , https://doi.org/10.1016/j.colsurfb.2020.110981
- Description: The fabricating of metal oxide thin films onto conducting surfaces continues to grow and their potential applications as surfaces for biosensor applications is of paramount importance. The correct orientation of glucose oxidase redox enzymes yields very important biointerfaces capable of selectively detecting D-glucose as a measure of blood sugar for healthy and diabetic sick patients. The electrodeposition of redox enzymes, such as glucose oxidase enzymes, onto gold electrode surfaces pre-modified with nickel oxide was investigated in this work.
- Full Text:
- Authors: Njoko, Nqobile , Louzada, Marcel , Britton, Jonathan , Khene, Samson M , Nyokong, Tebello , Mashazi, Philani N
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150071 , vital:38937 , https://doi.org/10.1016/j.colsurfb.2020.110981
- Description: The fabricating of metal oxide thin films onto conducting surfaces continues to grow and their potential applications as surfaces for biosensor applications is of paramount importance. The correct orientation of glucose oxidase redox enzymes yields very important biointerfaces capable of selectively detecting D-glucose as a measure of blood sugar for healthy and diabetic sick patients. The electrodeposition of redox enzymes, such as glucose oxidase enzymes, onto gold electrode surfaces pre-modified with nickel oxide was investigated in this work.
- Full Text:
Biological control of Salvinia molesta (DS Mitchell) drives aquatic ecosystem recovery
- Motitsoe, Samuel N, Coetzee, Julie A, Hill, Jaclyn M, Hill, Martin P
- Authors: Motitsoe, Samuel N , Coetzee, Julie A , Hill, Jaclyn M , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444515 , vital:74247 , https://doi.org/10.3390/d12050204
- Description: Salvinia molesta D.S. Mitchell (Salviniaceae) is a damaging free-floating invasive alien macrophyte native to South America. The biological control programme against S. molesta by the weevil Cyrtobagous salviniae Calder and Sands (Erirhinidae) has been successful in controlling S. molesta infestations in the introduced range, however, there is some debate as to how biological control success is measured. This study measured the response of epilithic algae and aquatic macroinvertebrate communities in a S. molesta-dominated state and subsequently where the weed had been cleared by biological control, as a proxy for ecosystem recovery in a before–after control–impact mesocosm experiment.
- Full Text:
- Authors: Motitsoe, Samuel N , Coetzee, Julie A , Hill, Jaclyn M , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444515 , vital:74247 , https://doi.org/10.3390/d12050204
- Description: Salvinia molesta D.S. Mitchell (Salviniaceae) is a damaging free-floating invasive alien macrophyte native to South America. The biological control programme against S. molesta by the weevil Cyrtobagous salviniae Calder and Sands (Erirhinidae) has been successful in controlling S. molesta infestations in the introduced range, however, there is some debate as to how biological control success is measured. This study measured the response of epilithic algae and aquatic macroinvertebrate communities in a S. molesta-dominated state and subsequently where the weed had been cleared by biological control, as a proxy for ecosystem recovery in a before–after control–impact mesocosm experiment.
- Full Text:
Biological control of water lettuce, Pistia stratiotes L., facilitates macroinvertebrate biodiversity recovery: a mesocosm study
- Coetzee, Julie A, Langa, Susana D, Motitsoe, Samuel N, Hill, Martin P
- Authors: Coetzee, Julie A , Langa, Susana D , Motitsoe, Samuel N , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423967 , vital:72112 , xlink:href="https://doi.org/10.1007/s10750-020-04369-w"
- Description: Floating aquatic weed infestations have negative socio-economic and environmental consequences to the ecosystems they invade. Despite the long history of invasion by macrophytes, only a few studies focus on their impacts on biodiversity, while the ecological benefits of biological control programmes against these species have been poorly quantified. We investigated the process of biotic homogenization following invasion by Pistia stratiotes on aquatic biodiversity, and recovery provided by biological control of this weed. Biotic homogenization is the increased similarity of biota as a result of introductions of non-native species. The study quantified the effect of P. stratiotes, and its biological control through the introduction of the weevil, Neohydronomus affinis on recruitment of benthic macroinvertebrates to artificial substrates. Mats of P. stratiotes altered the community composition and reduced diversity of benthic macroinvertebrates in comparison to an uninvaded control. However, reduction in percentage cover of the weed through biological control resulted in a significant increase in dissolved oxygen, and recovery of the benthic macroinvertebrate community that was comparable to the uninvaded state. This highlights the process of homogenization by an invasive macrophyte, providing a justification for sustained ecological and restoration efforts in the biological control of P. stratiotes where this plant is problematic.
- Full Text:
- Authors: Coetzee, Julie A , Langa, Susana D , Motitsoe, Samuel N , Hill, Martin P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423967 , vital:72112 , xlink:href="https://doi.org/10.1007/s10750-020-04369-w"
- Description: Floating aquatic weed infestations have negative socio-economic and environmental consequences to the ecosystems they invade. Despite the long history of invasion by macrophytes, only a few studies focus on their impacts on biodiversity, while the ecological benefits of biological control programmes against these species have been poorly quantified. We investigated the process of biotic homogenization following invasion by Pistia stratiotes on aquatic biodiversity, and recovery provided by biological control of this weed. Biotic homogenization is the increased similarity of biota as a result of introductions of non-native species. The study quantified the effect of P. stratiotes, and its biological control through the introduction of the weevil, Neohydronomus affinis on recruitment of benthic macroinvertebrates to artificial substrates. Mats of P. stratiotes altered the community composition and reduced diversity of benthic macroinvertebrates in comparison to an uninvaded control. However, reduction in percentage cover of the weed through biological control resulted in a significant increase in dissolved oxygen, and recovery of the benthic macroinvertebrate community that was comparable to the uninvaded state. This highlights the process of homogenization by an invasive macrophyte, providing a justification for sustained ecological and restoration efforts in the biological control of P. stratiotes where this plant is problematic.
- Full Text:
Biological control potential of ectomycorrhizal fungi against Fusarium circinatum on Pinus patula seedlings
- Chartier FitzGerald, Veronique C, Dames, Joanna F, Hawley, Grant L
- Authors: Chartier FitzGerald, Veronique C , Dames, Joanna F , Hawley, Grant L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425960 , vital:72302 , xlink:href="https://doi.org/10.1080/09583157.2020.1771542"
- Description: The South Africa forestry industry, covering ∼1.3 million hectares, is dependent on exotic pine and Eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess the effects of ectomycorrhizal fungal inoculation on Pinus patula seedling growth and resistance to the fungal pathogen F. circinatum. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates that were then verified via DNA extraction and PCR amplification and sequencing of the ITS rDNA region. These isolates were identified as Boletus edulis f. reticulatus, Lactarius quieticolor, Suillus granulatus and an unknown Suillus species. P. patula growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the L. quieticolor and Suillus isolates. Preventative inoculation of seedlings in the nursery using these isolates would ensure the production of stronger, healthier plants that would be more resistant to F. circinatum infection, increasing survival in the plantation.
- Full Text:
- Authors: Chartier FitzGerald, Veronique C , Dames, Joanna F , Hawley, Grant L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425960 , vital:72302 , xlink:href="https://doi.org/10.1080/09583157.2020.1771542"
- Description: The South Africa forestry industry, covering ∼1.3 million hectares, is dependent on exotic pine and Eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess the effects of ectomycorrhizal fungal inoculation on Pinus patula seedling growth and resistance to the fungal pathogen F. circinatum. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates that were then verified via DNA extraction and PCR amplification and sequencing of the ITS rDNA region. These isolates were identified as Boletus edulis f. reticulatus, Lactarius quieticolor, Suillus granulatus and an unknown Suillus species. P. patula growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the L. quieticolor and Suillus isolates. Preventative inoculation of seedlings in the nursery using these isolates would ensure the production of stronger, healthier plants that would be more resistant to F. circinatum infection, increasing survival in the plantation.
- Full Text:
Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys)
- Taylor, Peter J, Kearney, Theresa, Dalton, Desire L, Chakona, Gamuchirai, Kelly, Christopher M R, Barker, Nigel P
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M R , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453158 , vital:75227 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M R , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453158 , vital:75227 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys)
- Taylor, Peter J, Kearney, Theresa, Dalton, Desire L, Chakona, Gamuchirai, Kelly, Christopher M R, Barker, Nigel P
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M R , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
- Full Text:
- Authors: Taylor, Peter J , Kearney, Theresa , Dalton, Desire L , Chakona, Gamuchirai , Kelly, Christopher M R , Barker, Nigel P
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425481 , vital:72249 , xlink:href="https://doi.org/10.1093/zoolinnean/zlz134"
- Description: Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).
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Body mass and condition of a fynbos bird community investigating impacts of time, weather and raptor abundance from long-term citizen-science datasets
- Lee, Alan T K, Barnard, Phoebe, Fraser, Mike, Lennard, Chris, Smit, Ben, Oschadleus, Hans-Dieter
- Authors: Lee, Alan T K , Barnard, Phoebe , Fraser, Mike , Lennard, Chris , Smit, Ben , Oschadleus, Hans-Dieter
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441546 , vital:73897 , https://doi.org/10.2989/00306525.2019.1683093
- Description: Variation in body size, especially mass, is a function of local environmental conditions for any given species. Recent recorded decreases in body size of endotherms have been attributed to climate change in some cases. This prediction is based on the trend of smaller body size of endotherms in warmer climates (Bergmann’s rule) and it implies genetic responses rather than phenotypic flexibility. Alternatively, selection for smaller body size or lower mass could be explained by the starvation-predation hypothesis, where lighter individuals have a higher probability of escaping pursuing predators, such as raptors. Evidence that climate warming is driving patterns of size selection in birds in recent times has been mixed. We inspected data on 40 bird species contributed by bird ringers to the South African Ringing Scheme (SAFRING) for changes in body mass and condition as a function of time (year), minimum temperature of the day of capture, maximum temperature of the previous day, and rainfall data in the south-western Cape Floristic Region (fynbos) around Cape Town, South Africa, for the period 1988–2015. The region shows a warming trend over the study period (0.035 °C yr−1). Interannual body mass and condition change were poorly explained by year or temperature. High daily minimum temperature explained loss of body condition for four species, whereas evidence from recaptured birds indicated negative effects of increasing maximum daily temperature, as well as rain. For the alternative hypothesis, because raptor abundance is stable or only weakly declining, there is little evidence to suggest these as a driver influencing mass trends. Any decrease in body mass over the study period that we observed for birds appear more likely to be plastic responses to stress associated with temperature or rainfall at this time, rather than systematic selection for smaller body size, as predicted by Bergmann’s Rule.
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- Authors: Lee, Alan T K , Barnard, Phoebe , Fraser, Mike , Lennard, Chris , Smit, Ben , Oschadleus, Hans-Dieter
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441546 , vital:73897 , https://doi.org/10.2989/00306525.2019.1683093
- Description: Variation in body size, especially mass, is a function of local environmental conditions for any given species. Recent recorded decreases in body size of endotherms have been attributed to climate change in some cases. This prediction is based on the trend of smaller body size of endotherms in warmer climates (Bergmann’s rule) and it implies genetic responses rather than phenotypic flexibility. Alternatively, selection for smaller body size or lower mass could be explained by the starvation-predation hypothesis, where lighter individuals have a higher probability of escaping pursuing predators, such as raptors. Evidence that climate warming is driving patterns of size selection in birds in recent times has been mixed. We inspected data on 40 bird species contributed by bird ringers to the South African Ringing Scheme (SAFRING) for changes in body mass and condition as a function of time (year), minimum temperature of the day of capture, maximum temperature of the previous day, and rainfall data in the south-western Cape Floristic Region (fynbos) around Cape Town, South Africa, for the period 1988–2015. The region shows a warming trend over the study period (0.035 °C yr−1). Interannual body mass and condition change were poorly explained by year or temperature. High daily minimum temperature explained loss of body condition for four species, whereas evidence from recaptured birds indicated negative effects of increasing maximum daily temperature, as well as rain. For the alternative hypothesis, because raptor abundance is stable or only weakly declining, there is little evidence to suggest these as a driver influencing mass trends. Any decrease in body mass over the study period that we observed for birds appear more likely to be plastic responses to stress associated with temperature or rainfall at this time, rather than systematic selection for smaller body size, as predicted by Bergmann’s Rule.
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Body mass and condition of a fynbos bird community investigating impacts of time, weather and raptor abundance from long-term citizen-science datasets
- Lee, Alan T K, Barnard, Phoebe, Fraser, Mike, Lennard, Chris, Smit, Ben, Oschadleus, Hans-Dieter
- Authors: Lee, Alan T K , Barnard, Phoebe , Fraser, Mike , Lennard, Chris , Smit, Ben , Oschadleus, Hans-Dieter
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448383 , vital:74726 , https://doi.org/10.2989/00306525.2019.1683093
- Description: Variation in body size, especially mass, is a function of local environmental conditions for any given species. Recent recorded decreases in body size of endotherms have been attributed to climate change in some cases. This prediction is based on the trend of smaller body size of endotherms in warmer climates (Bergmann’s rule) and it implies genetic responses rather than phenotypic flexibility. Alternatively, selection for smaller body size or lower mass could be explained by the starvation-predation hypothesis, where lighter individuals have a higher probability of escaping pursuing predators, such as raptors. Evidence that climate warming is driving patterns of size selection in birds in recent times has been mixed. We inspected data on 40 bird species contributed by bird ringers to the South African Ringing Scheme (SAFRING) for changes in body mass and condition as a function of time (year), minimum temperature of the day of capture, maximum temperature of the previous day, and rainfall data in the south-western Cape Floristic Region (fynbos) around Cape Town, South Africa, for the period 1988–2015.
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- Authors: Lee, Alan T K , Barnard, Phoebe , Fraser, Mike , Lennard, Chris , Smit, Ben , Oschadleus, Hans-Dieter
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448383 , vital:74726 , https://doi.org/10.2989/00306525.2019.1683093
- Description: Variation in body size, especially mass, is a function of local environmental conditions for any given species. Recent recorded decreases in body size of endotherms have been attributed to climate change in some cases. This prediction is based on the trend of smaller body size of endotherms in warmer climates (Bergmann’s rule) and it implies genetic responses rather than phenotypic flexibility. Alternatively, selection for smaller body size or lower mass could be explained by the starvation-predation hypothesis, where lighter individuals have a higher probability of escaping pursuing predators, such as raptors. Evidence that climate warming is driving patterns of size selection in birds in recent times has been mixed. We inspected data on 40 bird species contributed by bird ringers to the South African Ringing Scheme (SAFRING) for changes in body mass and condition as a function of time (year), minimum temperature of the day of capture, maximum temperature of the previous day, and rainfall data in the south-western Cape Floristic Region (fynbos) around Cape Town, South Africa, for the period 1988–2015.
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Building knowledge with theory: Unpacking complexity in doctoral writing
- Authors: Wilmot, Kirsten
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439480 , vital:73600 , https://www.ajol.info/index.php/cristal/article/view/203971
- Description: The use of theory to analyse and interpret empirical data is a valued practice in much social science doctoral research. A crucial aspect of this practice involves generating sophisticated theoretical understandings and critiques of phenomena in our social world. Despite the importance of theory, however, few concrete explanations of how to ‘theorise’exist in literature. This paper addresses this gap by demonstrating how a set of conceptual tools can be used to unpack what the craft of theorising looks like in explicit terms, and to reveal how this ability develops over time during the drafting process of dissertation writing. It does this by drawing on select texts from a successful doctoral dissertation, as well as an earlier draft version. In doing so, the paper provides an in-depth explanation of an essential process of doctoral research that is inherently known by many supervisors, yet seldom unpacked in explicit terms.
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- Authors: Wilmot, Kirsten
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439480 , vital:73600 , https://www.ajol.info/index.php/cristal/article/view/203971
- Description: The use of theory to analyse and interpret empirical data is a valued practice in much social science doctoral research. A crucial aspect of this practice involves generating sophisticated theoretical understandings and critiques of phenomena in our social world. Despite the importance of theory, however, few concrete explanations of how to ‘theorise’exist in literature. This paper addresses this gap by demonstrating how a set of conceptual tools can be used to unpack what the craft of theorising looks like in explicit terms, and to reveal how this ability develops over time during the drafting process of dissertation writing. It does this by drawing on select texts from a successful doctoral dissertation, as well as an earlier draft version. In doing so, the paper provides an in-depth explanation of an essential process of doctoral research that is inherently known by many supervisors, yet seldom unpacked in explicit terms.
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Calling rhythm as a predictor of the outcome of vocal interactions: flight departure in pale-winged starling pairs
- Hausberger, Martine, Giacalone, Aline, Harmand, Mariane, Craig, Adrian J F K, Henry, Laurence
- Authors: Hausberger, Martine , Giacalone, Aline , Harmand, Mariane , Craig, Adrian J F K , Henry, Laurence
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449283 , vital:74808 , https://doi.org/10.1007/s00114-019-1658-1
- Description: Vocal communication plays an important role in the regulation of social interactions and the coordination of activities in many animal species. Synchrony is an essential part of the establishment and maintenance of pair bonds, but few reports have investigated decision-making at the pair level. We investigated temporal characteristics of call exchanges in pale-winged starlings (Onychognathus nabouroup) that could predict whether one, two, or neither members of a pair would take off. Our analysis of these interactions revealed that the overall rhythm of a call exchange, as well as the acceleration towards the end of an interaction, were significantly associated with the type of behavioural outcome. Faster rhythms were associated with higher probabilities that both birds would fly away. Our results confirm the findings of previous studies showing that higher rates of alarm calls indicate imminent departure and highlight the relationship between temporal features of vocal interactions and their outcome.
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- Authors: Hausberger, Martine , Giacalone, Aline , Harmand, Mariane , Craig, Adrian J F K , Henry, Laurence
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449283 , vital:74808 , https://doi.org/10.1007/s00114-019-1658-1
- Description: Vocal communication plays an important role in the regulation of social interactions and the coordination of activities in many animal species. Synchrony is an essential part of the establishment and maintenance of pair bonds, but few reports have investigated decision-making at the pair level. We investigated temporal characteristics of call exchanges in pale-winged starlings (Onychognathus nabouroup) that could predict whether one, two, or neither members of a pair would take off. Our analysis of these interactions revealed that the overall rhythm of a call exchange, as well as the acceleration towards the end of an interaction, were significantly associated with the type of behavioural outcome. Faster rhythms were associated with higher probabilities that both birds would fly away. Our results confirm the findings of previous studies showing that higher rates of alarm calls indicate imminent departure and highlight the relationship between temporal features of vocal interactions and their outcome.
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Can fishing tourism contribute to conservation and sustainability via ecotourism?: a case study of the Fishery for Giant African Threadfin Polydactylus quadrifilis on the Kwanza Estuary, Angola
- Butler, Edward C, Childs, Amber-Robyn, Saayman, Andrea, Potts, Warren M
- Authors: Butler, Edward C , Childs, Amber-Robyn , Saayman, Andrea , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149253 , vital:38819 , https://doi.org/10.3390/su12104221
- Description: It has been suggested that tourism fisheries can raise the value of landed catch, provide alternative livelihoods for local artisanal fishers and, because recreationally caught fishes are often released, simultaneously conserve stocks. However, for fishing tourism to meet ecotourism standards, sustainable, local economic benefit is imperative. This study aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary, Angola. The recreational fishery contributed significantly to economic productivity in an otherwise rural area, generating a total revenue (TR) of $236,826 per four-month fishing season.
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- Authors: Butler, Edward C , Childs, Amber-Robyn , Saayman, Andrea , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149253 , vital:38819 , https://doi.org/10.3390/su12104221
- Description: It has been suggested that tourism fisheries can raise the value of landed catch, provide alternative livelihoods for local artisanal fishers and, because recreationally caught fishes are often released, simultaneously conserve stocks. However, for fishing tourism to meet ecotourism standards, sustainable, local economic benefit is imperative. This study aimed to assess the direct economic contribution of the recreational fishery for Polydactylus quadrifilis on the Kwanza Estuary, Angola. The recreational fishery contributed significantly to economic productivity in an otherwise rural area, generating a total revenue (TR) of $236,826 per four-month fishing season.
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Characterisation of plasmodial transketolases and identification of potential inhibitors: an in silico study
- Boateng, Rita A, Tastan Bishop, Özlem, Musyoka, Thommas M
- Authors: Boateng, Rita A , Tastan Bishop, Özlem , Musyoka, Thommas M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429372 , vital:72605 , xlink:href="https://doi.org/10.1186/s12936-020-03512-1"
- Description: Plasmodial transketolase (PTKT) enzyme is one of the novel pharmacological targets being explored as potential anti-malarial drug target due to its functional role and low sequence identity to the human enzyme. Despite this, features contributing to such have not been exploited for anti-malarial drug design. Additionally, there are no anti-malarial drugs targeting PTKTs whereas the broad activity of these inhibitors against PTKTs from other Plasmodium spp. is yet to be reported. This study characterises different PTKTs [Plasmodium falciparum (PfTKT), Plasmodium vivax (PvTKT), Plasmodium ovale (PoTKT), Plasmodium malariae (PmTKT) and Plasmodium knowlesi (PkTKT) and the human homolog (HsTKT)] to identify key sequence and structural based differences as well as the identification of selective potential inhibitors against PTKTs.
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- Authors: Boateng, Rita A , Tastan Bishop, Özlem , Musyoka, Thommas M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429372 , vital:72605 , xlink:href="https://doi.org/10.1186/s12936-020-03512-1"
- Description: Plasmodial transketolase (PTKT) enzyme is one of the novel pharmacological targets being explored as potential anti-malarial drug target due to its functional role and low sequence identity to the human enzyme. Despite this, features contributing to such have not been exploited for anti-malarial drug design. Additionally, there are no anti-malarial drugs targeting PTKTs whereas the broad activity of these inhibitors against PTKTs from other Plasmodium spp. is yet to be reported. This study characterises different PTKTs [Plasmodium falciparum (PfTKT), Plasmodium vivax (PvTKT), Plasmodium ovale (PoTKT), Plasmodium malariae (PmTKT) and Plasmodium knowlesi (PkTKT) and the human homolog (HsTKT)] to identify key sequence and structural based differences as well as the identification of selective potential inhibitors against PTKTs.
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Charlie Hebdo as a critical event in a secondary school: Muslim students’ complex positioning in relation to the attack
- Tize, Carola, Berckmoes, Lidewyde, de Jong, Joop, Reis, Ria
- Authors: Tize, Carola , Berckmoes, Lidewyde , de Jong, Joop , Reis, Ria
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156400 , vital:39986 , DOI: 10.1177/1363461520903814
- Description: This paper examines responses to the 2015 terror attack on Charlie Hebdo, a French satirical magazine, amongst students in a secondary school in Berlin-Neukölln, Germany. The Charlie Hebdo attack occurred in the final weeks of a 19-month ethnographic study in the community. By analyzing the responses in the school to this critical event, we identify what is at stake for Muslim students.
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- Authors: Tize, Carola , Berckmoes, Lidewyde , de Jong, Joop , Reis, Ria
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156400 , vital:39986 , DOI: 10.1177/1363461520903814
- Description: This paper examines responses to the 2015 terror attack on Charlie Hebdo, a French satirical magazine, amongst students in a secondary school in Berlin-Neukölln, Germany. The Charlie Hebdo attack occurred in the final weeks of a 19-month ethnographic study in the community. By analyzing the responses in the school to this critical event, we identify what is at stake for Muslim students.
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Chemical archeoceanography:
- Albarede, Francis, Thibon, Fanny, Blichert-Toft, Janne, Tsikos, Harilaos
- Authors: Albarede, Francis , Thibon, Fanny , Blichert-Toft, Janne , Tsikos, Harilaos
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149065 , vital:38801 , https://doi.org/10.1016/j.chemgeo.2020.119625
- Description: Elemental fluxes to the ocean are expected to increase with the surface area of continental exposure to weathering and atmospheric PCO2. The record of phosphorus in sediments, which has no notable source within the ocean, and the radiogenic strontium isotopes in Archean carbonates indicate that, prior to the Great Oxidation Event (GOE), subaerial expanses represented only about 20% of the modern continental surface area, i.e. 7% of the surface of the Earth. Because these simple first-order observations, in contrast to the low oxygen content of the pre-GOE atmosphere, have so far received only little attention in the appraisal of the marine chemistry of the early Earth, a reassessment of the chemistry of the pre-GOE ocean is warranted. Here we discuss some of the geochemical cycles of the Archean world, including protons, alkalinity, electrons, and other electrolytes, and attempt to build a first conceptual framework for Chemical Archeoceanography.
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- Authors: Albarede, Francis , Thibon, Fanny , Blichert-Toft, Janne , Tsikos, Harilaos
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149065 , vital:38801 , https://doi.org/10.1016/j.chemgeo.2020.119625
- Description: Elemental fluxes to the ocean are expected to increase with the surface area of continental exposure to weathering and atmospheric PCO2. The record of phosphorus in sediments, which has no notable source within the ocean, and the radiogenic strontium isotopes in Archean carbonates indicate that, prior to the Great Oxidation Event (GOE), subaerial expanses represented only about 20% of the modern continental surface area, i.e. 7% of the surface of the Earth. Because these simple first-order observations, in contrast to the low oxygen content of the pre-GOE atmosphere, have so far received only little attention in the appraisal of the marine chemistry of the early Earth, a reassessment of the chemistry of the pre-GOE ocean is warranted. Here we discuss some of the geochemical cycles of the Archean world, including protons, alkalinity, electrons, and other electrolytes, and attempt to build a first conceptual framework for Chemical Archeoceanography.
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Chemical constituents, antioxidant and cytotoxicity properties of Leonotis leonurus used in the folklore management of neurological disorders in the Eastern Cape, South Africa
- Tonisi, Sipho, Okaiyeto, Kunle, Hoppe, Heinrich C, Mabinya, Leonard V, Nwodo, Uchechukwu U, Okoh, Anthony I
- Authors: Tonisi, Sipho , Okaiyeto, Kunle , Hoppe, Heinrich C , Mabinya, Leonard V , Nwodo, Uchechukwu U , Okoh, Anthony I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429384 , vital:72606 , xlink:href="https://doi.org/10.1007/s13205-020-2126-5"
- Description: In the present study, we evaluated the phytochemical compounds and antioxidant properties of chloroform, ethanol and acetone extracts for leaves and flowers of Leonutus leonurus (L. leonurus) alongside with their cytotoxic effects on human cervical carcinoma (HeLa) cell lines. The phytochemical compounds present in the leaves and flowers of L. leonurus included; phenolics, flavonoids and alkaloids. Their radicals scavenging effects against 2, 2-diphenyl-1-picrylhydrazyl [DPPH] 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) [ABTS·+], hydrogen peroxide, nitric oxide as well as metal chelating activities showed dose-dependent activities. Gas chromatography-mass spectrometry (GCMS) analyses revealed the presence of important bioactive compounds, which are associated with antioxidant; and the extracts exhibited toxicity effect against HeLa cells. The findings from this study divulge extracts of L. leonurus as prospective sources of antioxidant and anticancer agents; and hence, further study on their neuroprotective potentials becomes imperative.
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- Authors: Tonisi, Sipho , Okaiyeto, Kunle , Hoppe, Heinrich C , Mabinya, Leonard V , Nwodo, Uchechukwu U , Okoh, Anthony I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429384 , vital:72606 , xlink:href="https://doi.org/10.1007/s13205-020-2126-5"
- Description: In the present study, we evaluated the phytochemical compounds and antioxidant properties of chloroform, ethanol and acetone extracts for leaves and flowers of Leonutus leonurus (L. leonurus) alongside with their cytotoxic effects on human cervical carcinoma (HeLa) cell lines. The phytochemical compounds present in the leaves and flowers of L. leonurus included; phenolics, flavonoids and alkaloids. Their radicals scavenging effects against 2, 2-diphenyl-1-picrylhydrazyl [DPPH] 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) [ABTS·+], hydrogen peroxide, nitric oxide as well as metal chelating activities showed dose-dependent activities. Gas chromatography-mass spectrometry (GCMS) analyses revealed the presence of important bioactive compounds, which are associated with antioxidant; and the extracts exhibited toxicity effect against HeLa cells. The findings from this study divulge extracts of L. leonurus as prospective sources of antioxidant and anticancer agents; and hence, further study on their neuroprotective potentials becomes imperative.
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