Love at first bite? Pre-release surveys reveal a novel association between a native weevil and the invasive Nymphaea mexicana Zuccarini (Nymphaeaceae) in South Africa
- Reid, Megan, Hill, Martin P, Coetzee, Julie A
- Authors: Reid, Megan , Hill, Martin P , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416866 , vital:71392 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a19"
- Description: Classical biological control aims to suppress alien invasive plant populations by introducing host-specific natural enemies from the native range. This relies on the assumption that invasive plant populations in the invaded range benefit from the release of natural enemies. Pre-release surveys in the invaded range are a useful way to determine if enemy release applies to a particular invasive alien plant, and to determine what other factors may contribute to the invasion. Similarly, pre-release surveys gather information that can be used to compare invaded sites before and after the release of biological control agents and may also identify whether natural enemies have been accidentally introduced into the country. Pre-release surveys were conducted in South Africa on the invasive Nymphaea mexicana Zuccarini (Nymphaeaceae) to gather such information about this species, for which a biological control programme is being developed. There was lower diversity and abundance of herbivores in the native range compared to South Africa, suggesting that N. mexicana does experience enemy release at most sites in South Africa. This support for the enemy release hypothesis justifies the investment in biological control for its management. However, a native weevil, Bagous longulus Gyllenhal (Coleoptera: Curculionidae), was found feeding and reproducing on N. mexicana at three sites, resulting in damage to the leaves and suggesting that a novel association has formed between these species. Bagous longulus may have potential to be distributed to sites of N. mexicana where it is not present, though further investigation is necessary to confirm if its host range is suitable for this to be a safe endeavour. With the exception of sites where B. longulus was present, leaf sizes were large and damage was low, and there is no evidence that any natural enemies have been accidentally introduced from the native range. Findings such as these emphasise the importance of conducting thorough surveys during the development of biological control programmes.
- Full Text:
- Date Issued: 2023
- Authors: Reid, Megan , Hill, Martin P , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416866 , vital:71392 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a19"
- Description: Classical biological control aims to suppress alien invasive plant populations by introducing host-specific natural enemies from the native range. This relies on the assumption that invasive plant populations in the invaded range benefit from the release of natural enemies. Pre-release surveys in the invaded range are a useful way to determine if enemy release applies to a particular invasive alien plant, and to determine what other factors may contribute to the invasion. Similarly, pre-release surveys gather information that can be used to compare invaded sites before and after the release of biological control agents and may also identify whether natural enemies have been accidentally introduced into the country. Pre-release surveys were conducted in South Africa on the invasive Nymphaea mexicana Zuccarini (Nymphaeaceae) to gather such information about this species, for which a biological control programme is being developed. There was lower diversity and abundance of herbivores in the native range compared to South Africa, suggesting that N. mexicana does experience enemy release at most sites in South Africa. This support for the enemy release hypothesis justifies the investment in biological control for its management. However, a native weevil, Bagous longulus Gyllenhal (Coleoptera: Curculionidae), was found feeding and reproducing on N. mexicana at three sites, resulting in damage to the leaves and suggesting that a novel association has formed between these species. Bagous longulus may have potential to be distributed to sites of N. mexicana where it is not present, though further investigation is necessary to confirm if its host range is suitable for this to be a safe endeavour. With the exception of sites where B. longulus was present, leaf sizes were large and damage was low, and there is no evidence that any natural enemies have been accidentally introduced from the native range. Findings such as these emphasise the importance of conducting thorough surveys during the development of biological control programmes.
- Full Text:
- Date Issued: 2023
A Sn (iv) porphyrin with mitochondria targeting properties for enhanced photodynamic activity against MCF-7 cells
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230897 , vital:49829 , xlink:href="https://doi.org/10.1039/D2NJ00350C"
- Description: Two readily synthesized Sn(IV) porphyrins (SnP, SnPH) have been prepared with and without the cationic triphenylphosphonium moiety (TPP+), which have high singlet oxygen quantum yields (ca. 0.72) and long triplet state lifetimes. The Sn(IV) porphyrin with a TPP+ moiety (SnPH) exhibits favorable photodynamic activity against MCF-7 cells with IC50 values of 2.9 μM. SnPH exhibits higher cellular uptake than SnP in MCF-7 cells. A Rhodamine 123 (Rh123) assay showed that SnPH targets mitochondria and induces apoptosis by generating reactive oxygen species. The results demonstrate that this structural modification strategy merits further in-depth study.
- Full Text:
- Date Issued: 2022
Comparative avifaunal richness and diversity in invasive Acacia dealbata patches and adjacent montane grasslands
- Seath, Jessica, Shackleton, Charles M
- Authors: Seath, Jessica , Shackleton, Charles M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406585 , vital:70287 , xlink:href="https://hdl.handle.net/10520/ejc-afzoo_v57_i1_a12"
- Description: Abstract Invasive alien species are regarded as the second greatest threat to biodiversity globally. Yet, at a local scale their effects may vary, underlying the requirement for more local-scale studies across taxa and settings. Here we consider the effects of an alien invasive tree (Acacia dealbata, 5–8 m tall) on avifaunal numbers, richness and diversity in A. dealbata patches of three sizes relative to adjacent montane grasslands. Analysis of historical aerial photographs showed that A. dealbata first occurred in the area in the late 1930s/early 1940s and has continued to spread, despite some efforts by the landowner to keep it in check. It now covers approximately 11% of the site. This has provided habitat for a number of bird species more characteristic of wooded vegetation types. The number, richness and diversity of birds were greater in A. dealbata patches than the adjacent grasslands of equivalent size. These measures increased with increasing patch size, but more rapidly for A. dealbata patches than grassland ones. Only six of the 48 species of birds recorded were common between the two vegetation types. The most common feeding guild in the A. dealbata patches was insectivores, whereas in the grasslands it was omnivores. Although the invasion of A. dealbata has added to the habitat diversity of the area, thereby facilitating increased avifaunal diversity, if it continues to spread, then the populations and perhaps richness of grassland birds are likely to be negatively affected.
- Full Text:
- Date Issued: 2022
- Authors: Seath, Jessica , Shackleton, Charles M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406585 , vital:70287 , xlink:href="https://hdl.handle.net/10520/ejc-afzoo_v57_i1_a12"
- Description: Abstract Invasive alien species are regarded as the second greatest threat to biodiversity globally. Yet, at a local scale their effects may vary, underlying the requirement for more local-scale studies across taxa and settings. Here we consider the effects of an alien invasive tree (Acacia dealbata, 5–8 m tall) on avifaunal numbers, richness and diversity in A. dealbata patches of three sizes relative to adjacent montane grasslands. Analysis of historical aerial photographs showed that A. dealbata first occurred in the area in the late 1930s/early 1940s and has continued to spread, despite some efforts by the landowner to keep it in check. It now covers approximately 11% of the site. This has provided habitat for a number of bird species more characteristic of wooded vegetation types. The number, richness and diversity of birds were greater in A. dealbata patches than the adjacent grasslands of equivalent size. These measures increased with increasing patch size, but more rapidly for A. dealbata patches than grassland ones. Only six of the 48 species of birds recorded were common between the two vegetation types. The most common feeding guild in the A. dealbata patches was insectivores, whereas in the grasslands it was omnivores. Although the invasion of A. dealbata has added to the habitat diversity of the area, thereby facilitating increased avifaunal diversity, if it continues to spread, then the populations and perhaps richness of grassland birds are likely to be negatively affected.
- Full Text:
- Date Issued: 2022
Is green space associated with reduced crime? A national-scale study from the Global South
- Venter, Zander S, Shackleton, Charlie M, Faull, Andrew, Lancaster, Lizette, Breetzke, Gregory, Edelstein, Ian
- Authors: Venter, Zander S , Shackleton, Charlie M , Faull, Andrew , Lancaster, Lizette , Breetzke, Gregory , Edelstein, Ian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402340 , vital:69843 , xlink:href="https://doi.org/10.1016/j.scitotenv.2022.154005"
- Description: Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in the Global North. Little is known about the association between green spaces and crime in the Global South. We utilized 10 years of precinct-level crime statistics (n = 1152) over South Africa, a global crime hotspot, to test the hypothesis that green space is associated with reduced crime rates. We found that, after controlling for a number of socio-demographic confounders (unemployment, income, age, education, land use and population density), for every 1% increase in total green space there is a 1.2% (0.7 to 1.7%; 95% confidence interval) decrease in violent crime, and 1.3% (0.8 to 1.8%) decrease in property crime, with no effect on sexual crimes. However, the direction of the association changed for property crimes when exploring the effect of green space characteristics including tree cover and park accessibility. Property crimes increase by 0.4% (0.1 to 0.7%) with a percentage increase in tree cover, and by 0.9% (0.5 to 1.3%) with every kilometer increase in proximity to a public park. Further research, including experimental studies, is needed to better isolate causal mechanisms behind crime-green space associations, especially considering that green space may map to race and income inequality and that there may be more crime reporting in affluent areas. Nevertheless, our results provide a complementary contribution to the evidence from the Global North, highlighting the need for more nuanced definitions of green space and its characteristics when considering links to crime. When viewed in light of the broader suite of ecosystem services provided by green space, our results support urban greening as a major strategy towards achieving just and sustainable cities and towns.
- Full Text:
- Date Issued: 2022
- Authors: Venter, Zander S , Shackleton, Charlie M , Faull, Andrew , Lancaster, Lizette , Breetzke, Gregory , Edelstein, Ian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402340 , vital:69843 , xlink:href="https://doi.org/10.1016/j.scitotenv.2022.154005"
- Description: Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in the Global North. Little is known about the association between green spaces and crime in the Global South. We utilized 10 years of precinct-level crime statistics (n = 1152) over South Africa, a global crime hotspot, to test the hypothesis that green space is associated with reduced crime rates. We found that, after controlling for a number of socio-demographic confounders (unemployment, income, age, education, land use and population density), for every 1% increase in total green space there is a 1.2% (0.7 to 1.7%; 95% confidence interval) decrease in violent crime, and 1.3% (0.8 to 1.8%) decrease in property crime, with no effect on sexual crimes. However, the direction of the association changed for property crimes when exploring the effect of green space characteristics including tree cover and park accessibility. Property crimes increase by 0.4% (0.1 to 0.7%) with a percentage increase in tree cover, and by 0.9% (0.5 to 1.3%) with every kilometer increase in proximity to a public park. Further research, including experimental studies, is needed to better isolate causal mechanisms behind crime-green space associations, especially considering that green space may map to race and income inequality and that there may be more crime reporting in affluent areas. Nevertheless, our results provide a complementary contribution to the evidence from the Global North, highlighting the need for more nuanced definitions of green space and its characteristics when considering links to crime. When viewed in light of the broader suite of ecosystem services provided by green space, our results support urban greening as a major strategy towards achieving just and sustainable cities and towns.
- Full Text:
- Date Issued: 2022
Structural modification of RhIIItriarylcorroles for enhanced electrocatalyzed hydrogen evolution reactions
- Zhu, Weihua, Li, Lihua, Wang, Yu, Mack, John, Dingiswayo, Somila, Nyokong, Tebello, Liang, Xu
- Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
- Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
- Full Text:
- Date Issued: 2022
- Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
- Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
- Full Text:
- Date Issued: 2022
The implications of ortho-, meta-and para-directors on the in-vitro photodynamic antimicrobial chemotherapy activity of cationic pyridyl-dihydrothiazole phthalocyanines
- Magadla, Aviwe, Openda, Yolande Ikala, Nyokong, Tebello
- Authors: Magadla, Aviwe , Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295875 , vital:57386 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103029"
- Description: Cationic Zn phthalocyanine complexes were derived by alkylation reaction of tetra-(pyridinyloxy) phthalocyanines (Pcs) at the ortho, meta, and para positions to form Zn (II) tetrakis 3-(4-(2-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (2), Zn (II) tetrakis 3-(4-(3-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (4) and Zn (II) tetrakis 3-(4-(4-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (6). The photophysicochemical behaviors of the Pc complexes were assessed. The meta and para-substituted complexes gave high singlet oxygen quantum yields. The cationic Pcs demonstrated good planktonic antibacterial activity against Staphylococcus aureus and Escherichia coli with the high log reduction values of 9.29 and 8.55, respectively. The cationic complexes also showed a significant decrease in the viability of in vitro biofilms after photo-antimicrobial chemotherapy at 100 µM for both Staphylococcus aureus and Escherichia coli biofilms.
- Full Text:
- Date Issued: 2022
- Authors: Magadla, Aviwe , Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295875 , vital:57386 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103029"
- Description: Cationic Zn phthalocyanine complexes were derived by alkylation reaction of tetra-(pyridinyloxy) phthalocyanines (Pcs) at the ortho, meta, and para positions to form Zn (II) tetrakis 3-(4-(2-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (2), Zn (II) tetrakis 3-(4-(3-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (4) and Zn (II) tetrakis 3-(4-(4-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (6). The photophysicochemical behaviors of the Pc complexes were assessed. The meta and para-substituted complexes gave high singlet oxygen quantum yields. The cationic Pcs demonstrated good planktonic antibacterial activity against Staphylococcus aureus and Escherichia coli with the high log reduction values of 9.29 and 8.55, respectively. The cationic complexes also showed a significant decrease in the viability of in vitro biofilms after photo-antimicrobial chemotherapy at 100 µM for both Staphylococcus aureus and Escherichia coli biofilms.
- Full Text:
- Date Issued: 2022
An introduction to the fourth decadal review of biological control of invasive alien plants in South Africa (2011–2020)
- Paterson, Iain D, den Breeyen, Alana, Martin, Grant D, Olckers, Tamryn
- Authors: Paterson, Iain D , den Breeyen, Alana , Martin, Grant D , Olckers, Tamryn
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/413387 , vital:71031 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a2"
- Description: This special issue is the fourth decadal review of biological control of invasive alien plants (biocontrol of weeds) in South Africa, following those published in 1991, 1999 and 2011. Including this introduction, there are 24 papers covering the weed biocontrol programmes, or important developments in the science and practice, from the period 2011-2020. Seventy-two target weed species are covered, including 25 species on which projects were initiated during the past decade. Developments in regulations, mass-rearing and implementation, and community engagement are also reviewed. An updated catalogue of agents released, rejected and under consideration is presented and reflects the most recent methods of quantifying success in weed biocontrol. Key events over the last decade include the hosting of the XIV International Symposium on Biological Control of Weeds to celebrate 100 years of weed biocontrol in South Africa, as well as the establishment of the Centre for Biological Control at Rhodes University. The science and practice of weed biocontrol has expanded significantly in the past decade, with growth in the number of researchers and practitioners, increased funding, and an increased number of scholarly outputs. Unlike many other countries in the world, South Africa has largely avoided constraints due to restrictive and risk averse legislation and bureaucracy, and has continued to release new biocontrol agents at a similar rate to that in previous years. Much of the success of weed biocontrol in South Africa is due to the sustained and increasing support of the Natural Resource Management Programme of the Department of Forestry, Fisheries and the Environment (Working for Water Programme). However, gaps in funding, where no funds are available for months at a time, are a major concern as the weed biocontrol community loses human capital in these periods, and research programmes suffer significant set-backs. Weed biocontrol is an essential component of South Africa’s strategy to reduce the negative impacts of invasive alien plants and has contributed significantly towards the protection of the country’s ecosystems, indigenous biodiversity, water security, agricultural productivity, and society in general. If the trend of increasing support for weed biocontrol in South Africa continues, we can expect that the benefits for the country at large will increase substantially in the future.
- Full Text:
- Date Issued: 2021
- Authors: Paterson, Iain D , den Breeyen, Alana , Martin, Grant D , Olckers, Tamryn
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/413387 , vital:71031 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a2"
- Description: This special issue is the fourth decadal review of biological control of invasive alien plants (biocontrol of weeds) in South Africa, following those published in 1991, 1999 and 2011. Including this introduction, there are 24 papers covering the weed biocontrol programmes, or important developments in the science and practice, from the period 2011-2020. Seventy-two target weed species are covered, including 25 species on which projects were initiated during the past decade. Developments in regulations, mass-rearing and implementation, and community engagement are also reviewed. An updated catalogue of agents released, rejected and under consideration is presented and reflects the most recent methods of quantifying success in weed biocontrol. Key events over the last decade include the hosting of the XIV International Symposium on Biological Control of Weeds to celebrate 100 years of weed biocontrol in South Africa, as well as the establishment of the Centre for Biological Control at Rhodes University. The science and practice of weed biocontrol has expanded significantly in the past decade, with growth in the number of researchers and practitioners, increased funding, and an increased number of scholarly outputs. Unlike many other countries in the world, South Africa has largely avoided constraints due to restrictive and risk averse legislation and bureaucracy, and has continued to release new biocontrol agents at a similar rate to that in previous years. Much of the success of weed biocontrol in South Africa is due to the sustained and increasing support of the Natural Resource Management Programme of the Department of Forestry, Fisheries and the Environment (Working for Water Programme). However, gaps in funding, where no funds are available for months at a time, are a major concern as the weed biocontrol community loses human capital in these periods, and research programmes suffer significant set-backs. Weed biocontrol is an essential component of South Africa’s strategy to reduce the negative impacts of invasive alien plants and has contributed significantly towards the protection of the country’s ecosystems, indigenous biodiversity, water security, agricultural productivity, and society in general. If the trend of increasing support for weed biocontrol in South Africa continues, we can expect that the benefits for the country at large will increase substantially in the future.
- Full Text:
- Date Issued: 2021
Grand challenges in urban agriculture: ecological and social approaches to transformative sustainability
- Zimmerer, Karl S, Bell, Martha G, Chirisa, Innocent, Duvall, Chris S, Egerer, Monika, Hung, Po-Yi, Lerner, Amy M, Shackleton, Charlie M, Ward, James D, Ochoa, Carolina Y
- Authors: Zimmerer, Karl S , Bell, Martha G , Chirisa, Innocent , Duvall, Chris S , Egerer, Monika , Hung, Po-Yi , Lerner, Amy M , Shackleton, Charlie M , Ward, James D , Ochoa, Carolina Y
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402287 , vital:69838 , xlink:href="https://doi.org/10.3389/fsufs.2021.668561"
- Description: This synopsis of the Grand Challenges of Urban Agriculture (UA) is framed by the urgent need to understand and strengthen the expanding yet highly diverse roles of UA amid rapid global urbanization, failures of predominant food systems, and crises in systems of physical and mental health. More than half of humanity lives in cities today and by 2030 this is projected to grow to 60.4 percent, ∼5 billion people (UN Habitat, 2020). More than 90 percent of urban demographic increase is anticipated to take place in the developing world. Ecological and social dimensions of UA are situated in these expanding spaces of cities, towns, and villages (along with their urban fringe or peri-urban areas), and among their diverse populations. UA is further situated in the powerful, far-reaching influences of urbanization processes that occur within and beyond these spaces. UA is thus integral to the prospect of Urban Sustainability as SDG 11 (“Make cities and human settlements inclusive, safe, resilient and sustainable”) of the U.N.’s 2030 Agenda for Sustainable Development.
- Full Text:
- Date Issued: 2021
- Authors: Zimmerer, Karl S , Bell, Martha G , Chirisa, Innocent , Duvall, Chris S , Egerer, Monika , Hung, Po-Yi , Lerner, Amy M , Shackleton, Charlie M , Ward, James D , Ochoa, Carolina Y
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402287 , vital:69838 , xlink:href="https://doi.org/10.3389/fsufs.2021.668561"
- Description: This synopsis of the Grand Challenges of Urban Agriculture (UA) is framed by the urgent need to understand and strengthen the expanding yet highly diverse roles of UA amid rapid global urbanization, failures of predominant food systems, and crises in systems of physical and mental health. More than half of humanity lives in cities today and by 2030 this is projected to grow to 60.4 percent, ∼5 billion people (UN Habitat, 2020). More than 90 percent of urban demographic increase is anticipated to take place in the developing world. Ecological and social dimensions of UA are situated in these expanding spaces of cities, towns, and villages (along with their urban fringe or peri-urban areas), and among their diverse populations. UA is further situated in the powerful, far-reaching influences of urbanization processes that occur within and beyond these spaces. UA is thus integral to the prospect of Urban Sustainability as SDG 11 (“Make cities and human settlements inclusive, safe, resilient and sustainable”) of the U.N.’s 2030 Agenda for Sustainable Development.
- Full Text:
- Date Issued: 2021
How people foraging in urban greenspace can mobilize social–ecological resilience during Covid-19 and beyond
- Sardeshpande, Mallika, Hurley, P T, Mollee, Eefke, Garekae, Hesekia, Dahlberg, Annika C, Emery, Marla R, Shackleton, Charlie M
- Authors: Sardeshpande, Mallika , Hurley, P T , Mollee, Eefke , Garekae, Hesekia , Dahlberg, Annika C , Emery, Marla R , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402313 , vital:69841 , xlink:href="https://doi.org/10.3389/frsc.2021.686254"
- Description: Informal foraging for food and other natural materials in urban greenspaces is an activity undertaken by many across the world. For some, foraging is a necessary means of survival and livelihood, while for others, it provides cultural and recreational opportunities. In the socioeconomic crises induced by Covid-19, foraging can help communities, especially (but not exclusively) vulnerable people, cope with the impacts of lockdowns, and associated economic decline. In the long run, foraging can help improve social–ecological resilience in urban systems, particularly in response to climate, economic, and disease disruptions. First, we elaborate the ways in which urban foraging can provide immediate relief from the shocks to natural, human, social, physical, and financial capital. We then describe how over time, the livelihood, food, and income diversification brought about by foraging can contribute to preparedness for future uncertainties and gradual change. Cities are increasingly becoming home to the majority of humanity, and urban foraging can be one of the pathways that makes cities more liveable, for humans as well as other species we coexist with. Through the capitals framework, we explore the role foraging could play in addressing issues of biodiversity conservation, culture, and education, good governance and social justice, multifunctional greenspace, and sustainable nature-based livelihoods in urban areas.
- Full Text:
- Date Issued: 2021
- Authors: Sardeshpande, Mallika , Hurley, P T , Mollee, Eefke , Garekae, Hesekia , Dahlberg, Annika C , Emery, Marla R , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402313 , vital:69841 , xlink:href="https://doi.org/10.3389/frsc.2021.686254"
- Description: Informal foraging for food and other natural materials in urban greenspaces is an activity undertaken by many across the world. For some, foraging is a necessary means of survival and livelihood, while for others, it provides cultural and recreational opportunities. In the socioeconomic crises induced by Covid-19, foraging can help communities, especially (but not exclusively) vulnerable people, cope with the impacts of lockdowns, and associated economic decline. In the long run, foraging can help improve social–ecological resilience in urban systems, particularly in response to climate, economic, and disease disruptions. First, we elaborate the ways in which urban foraging can provide immediate relief from the shocks to natural, human, social, physical, and financial capital. We then describe how over time, the livelihood, food, and income diversification brought about by foraging can contribute to preparedness for future uncertainties and gradual change. Cities are increasingly becoming home to the majority of humanity, and urban foraging can be one of the pathways that makes cities more liveable, for humans as well as other species we coexist with. Through the capitals framework, we explore the role foraging could play in addressing issues of biodiversity conservation, culture, and education, good governance and social justice, multifunctional greenspace, and sustainable nature-based livelihoods in urban areas.
- Full Text:
- Date Issued: 2021
Positively charged styryl pyridine substituted Zn (II) Phthalocyanines for Photodynamic Therapy and Photoantimicrobial Chemotherapy
- Magadla, Aviwe, Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Magadla, Aviwe , Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190600 , vital:45009 , xlink:href="https://doi.org/10.1039/D1DT01047F"
- Description: Cationic Zn phthalocyanine complexes were synthesized using Knoevenagel reaction starting from a Zn(II) tetrakis(2-formylphenoxy)phthalocyanine (1) to form Zn(II) tetrakis(1-butyl-4-(4-(tetraphenoxy)styryl)pyridin-1-ium) phthalocyanine (2) and Zn(II) tetrakis(4-(4-(tetraphenoxy)styryl)-1-(4-(triphenylphosphonio)butyl)pyridin-1-ium)phthalocyanine (3). The photophysicochemical behaviours of the Pc complexes were assessed. The cationic complexes display high water-solubility and gave moderate singlet oxygen quantum yield in water. The cationic Pcs demonstrate good cellular uptake and photodynamic activity against MCF-7 cells with IC50 values of 8.2 and 4.9 μM for 2 and 3, respectively. The cationic Pcs also demonstrate high photoantimicrobial activity against Escherichia coli with log reductions of 5.3 and 6.0 for 2 and 3, respectively.
- Full Text:
- Date Issued: 2021
- Authors: Magadla, Aviwe , Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190600 , vital:45009 , xlink:href="https://doi.org/10.1039/D1DT01047F"
- Description: Cationic Zn phthalocyanine complexes were synthesized using Knoevenagel reaction starting from a Zn(II) tetrakis(2-formylphenoxy)phthalocyanine (1) to form Zn(II) tetrakis(1-butyl-4-(4-(tetraphenoxy)styryl)pyridin-1-ium) phthalocyanine (2) and Zn(II) tetrakis(4-(4-(tetraphenoxy)styryl)-1-(4-(triphenylphosphonio)butyl)pyridin-1-ium)phthalocyanine (3). The photophysicochemical behaviours of the Pc complexes were assessed. The cationic complexes display high water-solubility and gave moderate singlet oxygen quantum yield in water. The cationic Pcs demonstrate good cellular uptake and photodynamic activity against MCF-7 cells with IC50 values of 8.2 and 4.9 μM for 2 and 3, respectively. The cationic Pcs also demonstrate high photoantimicrobial activity against Escherichia coli with log reductions of 5.3 and 6.0 for 2 and 3, respectively.
- Full Text:
- Date Issued: 2021
Thien-2-yl substituted chlorins as photosensitizers for photodynamic therapy and photodynamic antimicrobial chemotherapy
- Babu, Balaji, Sindelo, Azole, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Sindelo, Azole , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190578 , vital:45007 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108886"
- Description: The synthesis and characterization of meso-tetra(thien-2-yl)chlorin (1) and meso-tetra(5-bromothien-2-yl)chlorin (2) is reported. These dyes have red-shifted absorption maxima compared to those of the analogous meso-tetraphenylchlorin (3). 1 and 2 have Q bands at 660 and 664 nm, respectively, singlet oxygen quantum yields of 0.60 and 0.64 and exhibit good photostability. The triplet states were found to have lifetimes of 8.6 μs in N2 purged DMF. Time-dependent cellular uptake of chlorins reached a maximum in MCF-7 cancer cells after 12 h. Upon irradiation with a Thorlabs M660L3 LED (280 mW cm−2), 2 exhibited better photocytotoxicity with an IC50 value of 2.7 μM against MCF-7 cells. The 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFDA) assay provided evidence for intracellular generation of reactive oxygen species. Photodynamic inactivation of bacteria by the chlorins was also studied. 2 exhibits better activity with log reduction values of 7.42 and 8.34 towards Staphylococcus aureus and Escherichia coli, respectively, under illumination for 60 min at 660 nm with a Thorlabs M660L3 LED (280 mW cm−2). These results demonstrate that 2 is a promising candidate for future in vivo experiments and merits further in-depth investigation.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Sindelo, Azole , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190578 , vital:45007 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108886"
- Description: The synthesis and characterization of meso-tetra(thien-2-yl)chlorin (1) and meso-tetra(5-bromothien-2-yl)chlorin (2) is reported. These dyes have red-shifted absorption maxima compared to those of the analogous meso-tetraphenylchlorin (3). 1 and 2 have Q bands at 660 and 664 nm, respectively, singlet oxygen quantum yields of 0.60 and 0.64 and exhibit good photostability. The triplet states were found to have lifetimes of 8.6 μs in N2 purged DMF. Time-dependent cellular uptake of chlorins reached a maximum in MCF-7 cancer cells after 12 h. Upon irradiation with a Thorlabs M660L3 LED (280 mW cm−2), 2 exhibited better photocytotoxicity with an IC50 value of 2.7 μM against MCF-7 cells. The 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFDA) assay provided evidence for intracellular generation of reactive oxygen species. Photodynamic inactivation of bacteria by the chlorins was also studied. 2 exhibits better activity with log reduction values of 7.42 and 8.34 towards Staphylococcus aureus and Escherichia coli, respectively, under illumination for 60 min at 660 nm with a Thorlabs M660L3 LED (280 mW cm−2). These results demonstrate that 2 is a promising candidate for future in vivo experiments and merits further in-depth investigation.
- Full Text:
- Date Issued: 2021
A comparative study of the photophysicochemical and photodynamic activity properties of meso-4-methylthiophenyl functionalized Sn (IV) tetraarylporphyrins and triarylcorroles
- Dingiswayo, Somila, Babu, Balaji, Prinsloo, Earl, Mack, John, Nyokong, Tebello
- Authors: Dingiswayo, Somila , Babu, Balaji , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186157 , vital:44469 , xlink:href="https://doi.org/10.1142/S1088424620500273"
- Description: Tin(IV) complexes of a 4-methylthiophenyl functionalized porphyrin (1-Sn) and its corrole analogue (2-Sn) were synthesized so that their photophysicochemical properties and photodynamic activities against MCF-7 breast cancer cells could be compared. Singlet oxygen luminescence studies revealed that 1-Sn and 2-Sn have comparable ΦΔΦΔ values in DMF of 0.59 and 0.60, respectively, while the IC5050 values after irradiation of MCF-7 cells for 30 min with a Thorlabs 625 nm LED (432 J · cm−2)−2) were determined to be 12.4 and 8.9 μμM. The results demonstrate that the cellular uptake of 2-Sn and its molar absorptivity at the irradiation wavelength play a crucial role during in vitro cytotoxicity studies.
- Full Text:
- Date Issued: 2020
- Authors: Dingiswayo, Somila , Babu, Balaji , Prinsloo, Earl , Mack, John , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186157 , vital:44469 , xlink:href="https://doi.org/10.1142/S1088424620500273"
- Description: Tin(IV) complexes of a 4-methylthiophenyl functionalized porphyrin (1-Sn) and its corrole analogue (2-Sn) were synthesized so that their photophysicochemical properties and photodynamic activities against MCF-7 breast cancer cells could be compared. Singlet oxygen luminescence studies revealed that 1-Sn and 2-Sn have comparable ΦΔΦΔ values in DMF of 0.59 and 0.60, respectively, while the IC5050 values after irradiation of MCF-7 cells for 30 min with a Thorlabs 625 nm LED (432 J · cm−2)−2) were determined to be 12.4 and 8.9 μμM. The results demonstrate that the cellular uptake of 2-Sn and its molar absorptivity at the irradiation wavelength play a crucial role during in vitro cytotoxicity studies.
- Full Text:
- Date Issued: 2020
Editorial for Special Issue: Education for Sustainability in a Time of Crises
- Authors: Rosenberg, Eureta
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370533 , vital:66352 , xlink:href="10.4314/sajee.v36i1.1"
- Description: There is an old and still popular saying that a crisis is an opportunity for change. The Chinese symbol for crisis is translated in Wikipedia as “danger at a point of juncture”. In the year 2020, first China and then the rest of humanity have been presented with a monumental crisis: a new and lethal virus that spread fast and far, causing actions and reactions, with dramatic consequences for social and economic life around the globe. Rebecca Solnit wrote of another crisis in her book Hope in the Dark: The Untold Story of People Power. In Grounds for Hope, a foreword to the 2015 edition (p.2), she stated: “This is an extraordinary time full of vital, transformative movements, that could not be foreseen. It’s also a nightmarish time. Full engagement requires the ability to perceive both.”.
- Full Text:
- Date Issued: 2020
- Authors: Rosenberg, Eureta
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370533 , vital:66352 , xlink:href="10.4314/sajee.v36i1.1"
- Description: There is an old and still popular saying that a crisis is an opportunity for change. The Chinese symbol for crisis is translated in Wikipedia as “danger at a point of juncture”. In the year 2020, first China and then the rest of humanity have been presented with a monumental crisis: a new and lethal virus that spread fast and far, causing actions and reactions, with dramatic consequences for social and economic life around the globe. Rebecca Solnit wrote of another crisis in her book Hope in the Dark: The Untold Story of People Power. In Grounds for Hope, a foreword to the 2015 edition (p.2), she stated: “This is an extraordinary time full of vital, transformative movements, that could not be foreseen. It’s also a nightmarish time. Full engagement requires the ability to perceive both.”.
- Full Text:
- Date Issued: 2020
Electronic and nonlinear optical properties of 2-(((5-aminonaphthalen-1-yl) imino) methyl) phenol
- Ojo, Nathanael D, Krause, Rui W M, Obi-Egbedi, Nelson O
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193397 , vital:45328 , xlink:href="https://doi.org/10.1016/j.molliq.2020.114157"
- Description: In this study, solvent dependence of electronic and nonlinear optical properties of a new Schiff base, 2-(((5-aminonaphthalen-1-yl)imino)methyl) phenol (DANOHB), has been investigated. Electronic and optical properties of the Schiff base studied using Uv-visible absorption and fluorescence spectroscopic techniques in solution show that the Schiff base exhibits fluorescence with a quantum yield of 0.21 and a Stokes shift of 39 nm. Quantum chemical calculations were performed on the Schiff base at time-dependent density functional level of theory using Becke-3-Lee-Yang-Parr method with 6-311++G(d,p) basis set. Solvent dependence of the excited state energies (EE), energy gap (ΔE), first-order (β) and second-order (γ) hyperpolarizabilities were studied in gas, cyclohexane and ethanol. The medium perturbed the energy levels which implies that the reactivity, activity and stability of the system are solvent sensitive. The γ is more than thirty times higher than urea (standard NLO material) and this property is further enhanced in less polar medium. Small ΔE and large hyperpolarizabilities obtained for this system suggest its good potential in photonics and nonlinear optical devices.
- Full Text:
- Date Issued: 2020
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193397 , vital:45328 , xlink:href="https://doi.org/10.1016/j.molliq.2020.114157"
- Description: In this study, solvent dependence of electronic and nonlinear optical properties of a new Schiff base, 2-(((5-aminonaphthalen-1-yl)imino)methyl) phenol (DANOHB), has been investigated. Electronic and optical properties of the Schiff base studied using Uv-visible absorption and fluorescence spectroscopic techniques in solution show that the Schiff base exhibits fluorescence with a quantum yield of 0.21 and a Stokes shift of 39 nm. Quantum chemical calculations were performed on the Schiff base at time-dependent density functional level of theory using Becke-3-Lee-Yang-Parr method with 6-311++G(d,p) basis set. Solvent dependence of the excited state energies (EE), energy gap (ΔE), first-order (β) and second-order (γ) hyperpolarizabilities were studied in gas, cyclohexane and ethanol. The medium perturbed the energy levels which implies that the reactivity, activity and stability of the system are solvent sensitive. The γ is more than thirty times higher than urea (standard NLO material) and this property is further enhanced in less polar medium. Small ΔE and large hyperpolarizabilities obtained for this system suggest its good potential in photonics and nonlinear optical devices.
- Full Text:
- Date Issued: 2020
Electronic and nonlinear optical properties of 3-(((2-substituted-4-nitrophenyl) imino) methyl) phenol
- Ojo, Nathanael D, Krause, Rui W M, Obi-Egbedi, Nelson O
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
- Authors: Ojo, Nathanael D , Krause, Rui W M , Obi-Egbedi, Nelson O
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193408 , vital:45329 , xlink:href="https://doi.org/10.1016/j.comptc.2020.113050"
- Description: This work entails the study of electronic and nonlinear optical (NLO) properties of two synthesized Schiff bases namely 3-(((2-methyl-4-nitrophenyl)imino)methyl)phenol (MMP) and 3-(((2,4-dinitrophenyl)imino)methyl)phenol (DMP). Electronic absorption properties studied using UV–Visible spectrophotometry in ethanol reveal low-energy absorption indicating a low band gap. Time-dependent density functional calculations on their excited state properties with ωB97X-D/6-311++G(d,p) method show comparable transition energies and intensities with the experimental results. Energy gaps (ΔE) and NLO properties were evaluated from the frontier orbitals and hyperpolarizabilities (βtot and γ) in gas, cyclohexane and ethanol. Low ΔE obtained shows the potentials of the systems as organic semiconductor with remarkable band gap stabilization in ethanol. Higher βtot and γ than urea imply that the Schiff bases possess potentials for NLO applications. The solvatochromic shift in transition energies and perturbation of electronic properties reveal the solvent dependence of the electronic and optical properties of MMP and DMP due to solute-solvent interactions.
- Full Text:
- Date Issued: 2020
Encapsulation and physicochemical evaluation of efavirenz in liposomes
- Okafor, Nnamdi Ikemefuna, Nkanga, Christian I, Walker, Roderick B, Noundou, Xavier S, Krause, Rui W M
- Authors: Okafor, Nnamdi Ikemefuna , Nkanga, Christian I , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183414 , vital:43988 , xlink:href="https://doi.org/10.1007/s40005-019-00458-8"
- Description: Antiretroviral therapy remains the most efective means of managing the human immune defciency virus/acquired immune defciency syndrome (HIV/AIDS). Application of therapeutics has been hampered by factors including poor bioavailability of most anti-retroviral compounds (ARV), side efects and an alarming emergence of drug resistant strains of the virus. Recent developments and use of drug delivery systems (DDS) has shown potential for improving the pharmacological profle of ARV. Amongst these complex DDS, liposomes have been explored for delivery of ARV. In this study, we have aimed at exploring efcient encapsulation of efavirenz (EFV), a potent ARV using diferent mass ratios of crude soybean lecithin and cholesterol. The EFV-loaded liposomes (EFL) were prepared using thin flm hydration and evaluated for particle size, zeta potential (ZP), encapsulation efciency (EE%), morphology and drug release studies. Diferential scanning calorimetry (DSC), X-ray difraction (XRD), energy dispersity spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy were used for comprehensive physicochemical characterization of EFL. EFL exhibited high encapsulation (99%) in 1:1 crude lecithin to cholesterol mass ratio. The average particle size and Zeta Potential of EFL were found to be 411.10±7.40 nm and −53.5.3±0.06 mV, respectively. EFL showed a relatively controlled EFV release behaviour that was similar to the dissolution profle of un-encapsulated EFV. This suggests that EFL represents a promising vehicle for efective EFV delivery while providing the advantages of a nano-scaled delivery system
- Full Text:
- Date Issued: 2020
- Authors: Okafor, Nnamdi Ikemefuna , Nkanga, Christian I , Walker, Roderick B , Noundou, Xavier S , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183414 , vital:43988 , xlink:href="https://doi.org/10.1007/s40005-019-00458-8"
- Description: Antiretroviral therapy remains the most efective means of managing the human immune defciency virus/acquired immune defciency syndrome (HIV/AIDS). Application of therapeutics has been hampered by factors including poor bioavailability of most anti-retroviral compounds (ARV), side efects and an alarming emergence of drug resistant strains of the virus. Recent developments and use of drug delivery systems (DDS) has shown potential for improving the pharmacological profle of ARV. Amongst these complex DDS, liposomes have been explored for delivery of ARV. In this study, we have aimed at exploring efcient encapsulation of efavirenz (EFV), a potent ARV using diferent mass ratios of crude soybean lecithin and cholesterol. The EFV-loaded liposomes (EFL) were prepared using thin flm hydration and evaluated for particle size, zeta potential (ZP), encapsulation efciency (EE%), morphology and drug release studies. Diferential scanning calorimetry (DSC), X-ray difraction (XRD), energy dispersity spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy were used for comprehensive physicochemical characterization of EFL. EFL exhibited high encapsulation (99%) in 1:1 crude lecithin to cholesterol mass ratio. The average particle size and Zeta Potential of EFL were found to be 411.10±7.40 nm and −53.5.3±0.06 mV, respectively. EFL showed a relatively controlled EFV release behaviour that was similar to the dissolution profle of un-encapsulated EFV. This suggests that EFL represents a promising vehicle for efective EFV delivery while providing the advantages of a nano-scaled delivery system
- Full Text:
- Date Issued: 2020
Exploring how a genetic attribution to disease relates to stigma experiences of Xhosa patients with schizophrenia in South Africa
- Matshabane, Olivia P, Campbell, Megan, Faure, Marlyn C, Marshall, Patricia A, Mayosi, Bongani M, Stein, Dan J, Appelbaum, Paul S, de Vries, Jantina
- Authors: Matshabane, Olivia P , Campbell, Megan , Faure, Marlyn C , Marshall, Patricia A , Mayosi, Bongani M , Stein, Dan J , Appelbaum, Paul S , de Vries, Jantina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302487 , vital:58201 , xlink:href="https://doi.org/10.1007/s00127-020-01875-z"
- Description: Background: Over the past three decades, a range of international stakeholders have highlighted the possibility that genomic research may impact stigma associated with psychiatric disorders. Limited research has been conducted in Africa to investigate this relation. Method In the present study, using focus group discussions, we explored the relation between genetic attribution and stigma among 36 Xhosa people with schizophrenia. We addressed three main questions: (1) What causal beliefs do Xhosa people with schizophrenia use to explain their illness and to what extent do genetic explanations play a role in these beliefs? (2) What are the internalised stigma experiences of Xhosa people with schizophrenia? (3) How do genetic explanations relate to stigma experiences, if at all? Results Most participants were able to define genetics and some linked genetics to disease causation. Despite adequate knowledge of genetics and an emphasis on genetic explanations of schizophrenia in the study, most participants held a multitude of causal explanations including: psychosocial, environmental, and cultural. Moreover, participants rarely mentioned disease cause when describing their stigma experiences. Discussion For this population group, there was no straight-forward relation between a genetic attribution and stigma. Therefore, we did not fnd evidence that genetic attribution may signifcantly increase stigma. Although North American and European literature provides conficting evidence regarding this relation, there is increased consensus that biomedical explanations for psychiatric disorders may reduce blame. This study found evidence supporting that consensus. This study provides an empirical foundation to inform ongoing work on the psychosocial implications of psychiatric genomics research in non-Western contexts.
- Full Text:
- Date Issued: 2020
- Authors: Matshabane, Olivia P , Campbell, Megan , Faure, Marlyn C , Marshall, Patricia A , Mayosi, Bongani M , Stein, Dan J , Appelbaum, Paul S , de Vries, Jantina
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302487 , vital:58201 , xlink:href="https://doi.org/10.1007/s00127-020-01875-z"
- Description: Background: Over the past three decades, a range of international stakeholders have highlighted the possibility that genomic research may impact stigma associated with psychiatric disorders. Limited research has been conducted in Africa to investigate this relation. Method In the present study, using focus group discussions, we explored the relation between genetic attribution and stigma among 36 Xhosa people with schizophrenia. We addressed three main questions: (1) What causal beliefs do Xhosa people with schizophrenia use to explain their illness and to what extent do genetic explanations play a role in these beliefs? (2) What are the internalised stigma experiences of Xhosa people with schizophrenia? (3) How do genetic explanations relate to stigma experiences, if at all? Results Most participants were able to define genetics and some linked genetics to disease causation. Despite adequate knowledge of genetics and an emphasis on genetic explanations of schizophrenia in the study, most participants held a multitude of causal explanations including: psychosocial, environmental, and cultural. Moreover, participants rarely mentioned disease cause when describing their stigma experiences. Discussion For this population group, there was no straight-forward relation between a genetic attribution and stigma. Therefore, we did not fnd evidence that genetic attribution may signifcantly increase stigma. Although North American and European literature provides conficting evidence regarding this relation, there is increased consensus that biomedical explanations for psychiatric disorders may reduce blame. This study found evidence supporting that consensus. This study provides an empirical foundation to inform ongoing work on the psychosocial implications of psychiatric genomics research in non-Western contexts.
- Full Text:
- Date Issued: 2020
First record of an indigenous South African parasitoid wasp on an imported biological control agent, the water hyacinth hopper
- Kraus, Emily C, Coetzee, Julie A, van Noort, Simon, Olmi, Massimo
- Authors: Kraus, Emily C , Coetzee, Julie A , van Noort, Simon , Olmi, Massimo
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417700 , vital:71479 , xlink:href="https://doi.org/10.1080/09583157.2019.1660306"
- Description: Water hyacinth, Pontederia crassipes (Martius) [≡Eichhornia crassip es (Martius) Solms-Laubach] (Pontederiaceae), is native to South America, but has expanded its range to many other regions of the world including South Africa. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released as a biological control agent and has established in several regions. Recently, the indigenous species Echthrodelphax migratorius Benoit, (Hymenoptera: Dryinidae) was discovered in South Africa parasitising M. scutellaris. This newly discovered relationship might have repercussions for the efficacy of biological control of water hyacinth by the delphacid. The wasp may negatively impact M. scutellaris populations making it difficult for the agent to successfully manage the invasive weed. Contrarily, the parasitoid may be beneficial by keeping the M. scutellaris populations stable, serving as a natural enemy.
- Full Text:
- Date Issued: 2020
- Authors: Kraus, Emily C , Coetzee, Julie A , van Noort, Simon , Olmi, Massimo
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417700 , vital:71479 , xlink:href="https://doi.org/10.1080/09583157.2019.1660306"
- Description: Water hyacinth, Pontederia crassipes (Martius) [≡Eichhornia crassip es (Martius) Solms-Laubach] (Pontederiaceae), is native to South America, but has expanded its range to many other regions of the world including South Africa. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released as a biological control agent and has established in several regions. Recently, the indigenous species Echthrodelphax migratorius Benoit, (Hymenoptera: Dryinidae) was discovered in South Africa parasitising M. scutellaris. This newly discovered relationship might have repercussions for the efficacy of biological control of water hyacinth by the delphacid. The wasp may negatively impact M. scutellaris populations making it difficult for the agent to successfully manage the invasive weed. Contrarily, the parasitoid may be beneficial by keeping the M. scutellaris populations stable, serving as a natural enemy.
- Full Text:
- Date Issued: 2020
Genetic diversity and morphological variation in African boxthorn (Lycium ferocissimum)–characterising the target weed for biological control
- McCulloch, Graham A, Mauda, Evans V, Chari, L D, Martin, Grant D, Gurdasani, Komal, Morin, L, Walter, G H, Raghu, S
- Authors: McCulloch, Graham A , Mauda, Evans V , Chari, L D , Martin, Grant D , Gurdasani, Komal , Morin, L , Walter, G H , Raghu, S
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423474 , vital:72064 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104206"
- Description: Lycium ferocissimum (African boxthorn) is a Weed of National Significance in Australia. Biological control may have potential to manage this weed, but taxonomic uncertainty needs to be addressed first to facilitate searches for potential agents. We sampled putative L. ferocissimum (i.e. tentatively identified morphologically in the field) across its native range in South Africa and introduced range in Australia. Morphometric and genetic analyses were conducted to confirm the species identity of these samples, and to assess morphological and genetic variation across both ranges. All samples collected in Australia were confirmed as L. ferocissimum, with no evidence of hybridisation with any other Lycium species. Nuclear and chloroplast genetic diversity within L. ferocissimum across both South Africa and Australia was low, with no evidence of genetic structure. One of the two common chloroplast haplotypes found across Australia was found at only two sites in South Africa, both near Cape Town, suggesting that the Australian lineage may have originated from this region. Ten samples from South Africa putatively identified in the field as L. ferocissimum were genetically characterised as different (unidentified) Lycium species. Our morphometric analyses across different Lycium species in South Africa did not identify any leaf or floral characteristics unique to L. ferocissimum, and thus morphological identification of the latter species in its native range may remain problematic. To ensure the correct Lycium species is surveyed for candidate biological control agents we suggest that individuals should be permanently tagged and putative morphological determinations supplemented with genetic analyses to confirm species identity.
- Full Text:
- Date Issued: 2020
- Authors: McCulloch, Graham A , Mauda, Evans V , Chari, L D , Martin, Grant D , Gurdasani, Komal , Morin, L , Walter, G H , Raghu, S
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423474 , vital:72064 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104206"
- Description: Lycium ferocissimum (African boxthorn) is a Weed of National Significance in Australia. Biological control may have potential to manage this weed, but taxonomic uncertainty needs to be addressed first to facilitate searches for potential agents. We sampled putative L. ferocissimum (i.e. tentatively identified morphologically in the field) across its native range in South Africa and introduced range in Australia. Morphometric and genetic analyses were conducted to confirm the species identity of these samples, and to assess morphological and genetic variation across both ranges. All samples collected in Australia were confirmed as L. ferocissimum, with no evidence of hybridisation with any other Lycium species. Nuclear and chloroplast genetic diversity within L. ferocissimum across both South Africa and Australia was low, with no evidence of genetic structure. One of the two common chloroplast haplotypes found across Australia was found at only two sites in South Africa, both near Cape Town, suggesting that the Australian lineage may have originated from this region. Ten samples from South Africa putatively identified in the field as L. ferocissimum were genetically characterised as different (unidentified) Lycium species. Our morphometric analyses across different Lycium species in South Africa did not identify any leaf or floral characteristics unique to L. ferocissimum, and thus morphological identification of the latter species in its native range may remain problematic. To ensure the correct Lycium species is surveyed for candidate biological control agents we suggest that individuals should be permanently tagged and putative morphological determinations supplemented with genetic analyses to confirm species identity.
- Full Text:
- Date Issued: 2020
Host stage preference and performance of Dolichogenidea gelechiidivoris (Hymenoptera: Braconidae), a candidate for classical biological control of Tuta absoluta in Africa
- Aigbedion-Atalor, Pascal O, Mohamed, Samira A, Hill, Martin P, Zalucki, Myron P, Azrag, Abdelmutalab G A, Srinivasan, Ramasamy, Ekesi, Sunday
- Authors: Aigbedion-Atalor, Pascal O , Mohamed, Samira A , Hill, Martin P , Zalucki, Myron P , Azrag, Abdelmutalab G A , Srinivasan, Ramasamy , Ekesi, Sunday
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423516 , vital:72068 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104215"
- Description: Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is native to South America but has invaded the Afro-Eurasian supercontinent where it is currently the most devastating invasive arthropod pest of tomato. As a part of the first classical biological control programme against T. absoluta in Africa, a larval parasitoid, Dolichogenidea gelechiidivoris Marsh. (Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta was imported from Peru into the quarantine facility of the International Centre of Insect Physiology and Ecology, Kenya. We report on the host larval preference of D. gelechiidivoris and the host suitability, and the parasitoid’s reproductive strategy, including lifetime fecundity and egg maturation dynamics. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post eclosion. The females of D. gelechiidivoris survived 8.51 ± 0.65 d and produced 103 ± 8 offspring per female at 26 ± 4 °C (range: 24 to 29 °C) and 50–70% relative humidity (RH) with males present and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The potential intrinsic rate of natural increase was 0.18. This study shows that D. gelechiidivoris is a potential biological control agent of T. absoluta and should be considered for release in Kenya and across Africa following host specificity testing and risk assessments.
- Full Text:
- Date Issued: 2020
- Authors: Aigbedion-Atalor, Pascal O , Mohamed, Samira A , Hill, Martin P , Zalucki, Myron P , Azrag, Abdelmutalab G A , Srinivasan, Ramasamy , Ekesi, Sunday
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423516 , vital:72068 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104215"
- Description: Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is native to South America but has invaded the Afro-Eurasian supercontinent where it is currently the most devastating invasive arthropod pest of tomato. As a part of the first classical biological control programme against T. absoluta in Africa, a larval parasitoid, Dolichogenidea gelechiidivoris Marsh. (Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta was imported from Peru into the quarantine facility of the International Centre of Insect Physiology and Ecology, Kenya. We report on the host larval preference of D. gelechiidivoris and the host suitability, and the parasitoid’s reproductive strategy, including lifetime fecundity and egg maturation dynamics. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post eclosion. The females of D. gelechiidivoris survived 8.51 ± 0.65 d and produced 103 ± 8 offspring per female at 26 ± 4 °C (range: 24 to 29 °C) and 50–70% relative humidity (RH) with males present and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The potential intrinsic rate of natural increase was 0.18. This study shows that D. gelechiidivoris is a potential biological control agent of T. absoluta and should be considered for release in Kenya and across Africa following host specificity testing and risk assessments.
- Full Text:
- Date Issued: 2020