5-Fu inclusion complex capped gold nanoparticles for breast cancer therapy
- Lakkakula, Jaya R, Krause, Rui W M, Divakaran, Deepika, Barage, Sagar, Srivastava, Rohit
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
A decade of biological control of Parthenium hysterophorus L.(Asteraceae) in South Africa reviewed: introduction of insect agents and their status
- Strathie, L W, Cowie, Blair W, McConnachie, Andrew J, Chidawanyika, Frank, Musedeli, Jufter N, Sambo, SMC, Magoso, EX, Gareeb, M
- Authors: Strathie, L W , Cowie, Blair W , McConnachie, Andrew J , Chidawanyika, Frank , Musedeli, Jufter N , Sambo, SMC , Magoso, EX , Gareeb, M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416795 , vital:71386 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a11"
- Description: The annual herb, Parthenium hysterophorus L. (Asteraceae: Heliantheae) is a severe terrestrial invader globally. Infestations reduce crop yield, limit available grazing, hinder conservation efforts, and affect human and animal health in Africa, Asia and Australia, and on associated islands. Due to the impact and threat of further invasion of P. hysterophorus, a biological control (biocontrol) programme was initiated in 2003 in South Africa. This review discusses the research and implementation activities undertaken on the insect agents from 2011 to 2020. During this period, the stem-boring weevil Listronotus setosipennis Hustache (Coleoptera: Curculionidae), leaf-feeding beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) and seed-feeding weevil Smicronyx lutulentus Dietz (Coleoptera: Curculionidae), were found to be host specific and approved for release. Releases of mass-reared insect agents have been concentrated particularly in north-eastern South Africa, where P. hysterophorus infestations are most prolific. Post-release monitoring studies indicated localised establishment and impact of L. setosipennis and S. lutulentus. Listronotus setosipennis persisted through severe drought conditions, and although it disperses slowly, larval feeding is structurally damaging. Establishment of S. lutulentus is improving, reducing seed production where it is established. Zygogramma bicolorata resulted in defoliation at a few sites, but establishment has been poor and the beetle has been absent since 2019. Although a combination of fungal and insect agents were demonstrated to reduce P. hysterophorus, additional natural enemies could improve control. Consequently, the stem-galling moth Epiblema strenuana Walker (Lepidoptera: Tortricidae) and root-crown boring moth Carmenta sp. nr. ithacae (Beutenmüller) (Lepidoptera: Sesiidae) remain under evaluation. The management of P. hysterophorus in South Africa has been guided by the development of a national strategy, which incorporates multiple management methods, including biocontrol. International collaborations have intensified as a growing number of countries begin to utilize biocontrol to manage P. hysterophorus. Despite the progress towards biocontrol of P. hysterophorus during this period, increased utilisation of approved agents and the introduction of additional agents are necessary to achieve greater control.
- Full Text:
- Date Issued: 2021
- Authors: Strathie, L W , Cowie, Blair W , McConnachie, Andrew J , Chidawanyika, Frank , Musedeli, Jufter N , Sambo, SMC , Magoso, EX , Gareeb, M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416795 , vital:71386 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a11"
- Description: The annual herb, Parthenium hysterophorus L. (Asteraceae: Heliantheae) is a severe terrestrial invader globally. Infestations reduce crop yield, limit available grazing, hinder conservation efforts, and affect human and animal health in Africa, Asia and Australia, and on associated islands. Due to the impact and threat of further invasion of P. hysterophorus, a biological control (biocontrol) programme was initiated in 2003 in South Africa. This review discusses the research and implementation activities undertaken on the insect agents from 2011 to 2020. During this period, the stem-boring weevil Listronotus setosipennis Hustache (Coleoptera: Curculionidae), leaf-feeding beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) and seed-feeding weevil Smicronyx lutulentus Dietz (Coleoptera: Curculionidae), were found to be host specific and approved for release. Releases of mass-reared insect agents have been concentrated particularly in north-eastern South Africa, where P. hysterophorus infestations are most prolific. Post-release monitoring studies indicated localised establishment and impact of L. setosipennis and S. lutulentus. Listronotus setosipennis persisted through severe drought conditions, and although it disperses slowly, larval feeding is structurally damaging. Establishment of S. lutulentus is improving, reducing seed production where it is established. Zygogramma bicolorata resulted in defoliation at a few sites, but establishment has been poor and the beetle has been absent since 2019. Although a combination of fungal and insect agents were demonstrated to reduce P. hysterophorus, additional natural enemies could improve control. Consequently, the stem-galling moth Epiblema strenuana Walker (Lepidoptera: Tortricidae) and root-crown boring moth Carmenta sp. nr. ithacae (Beutenmüller) (Lepidoptera: Sesiidae) remain under evaluation. The management of P. hysterophorus in South Africa has been guided by the development of a national strategy, which incorporates multiple management methods, including biocontrol. International collaborations have intensified as a growing number of countries begin to utilize biocontrol to manage P. hysterophorus. Despite the progress towards biocontrol of P. hysterophorus during this period, increased utilisation of approved agents and the introduction of additional agents are necessary to achieve greater control.
- Full Text:
- Date Issued: 2021
A heavy-atom-free π-extended N-confused porphyrin as a photosensitizer for photodynamic therapy
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
- Full Text:
- Date Issued: 2021
A review of the biocontrol programmes against aquatic weeds in South Africa
- Coetzee, Julie A, Bownes, Angela, Martin, Grant D, Miller, Benjamin E, Smith, Rosalie, Weyl, Philip S R, Hill, Martin P
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D , Miller, Benjamin E , Smith, Rosalie , Weyl, Philip S R , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406965 , vital:70326 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a18"
- Description: Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis and Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.
- Full Text:
- Date Issued: 2021
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D , Miller, Benjamin E , Smith, Rosalie , Weyl, Philip S R , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406965 , vital:70326 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a18"
- Description: Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis and Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.
- Full Text:
- Date Issued: 2021
Adaptation and validation of a computerized neurocognitive battery in the Xhosa of South Africa
- Cobb, Scott J, Moore, Tyler M, Stein, Dan J, Pretorius, Adele, Zingela, Zukiswa, Nagdee, Mohammed, Ngqengelele, Linda, Campbell, Megan, Sibeko, Goodman, King, Mary C, McClellan, Jon M, Port, Allison M, Jackson, Chad, Ruparel, Kosha, Susser, Ezra, Gur, Ruben C
- Authors: Cobb, Scott J , Moore, Tyler M , Stein, Dan J , Pretorius, Adele , Zingela, Zukiswa , Nagdee, Mohammed , Ngqengelele, Linda , Campbell, Megan , Sibeko, Goodman , King, Mary C , McClellan, Jon M , Port, Allison M , Jackson, Chad , Ruparel, Kosha , Susser, Ezra , Gur, Ruben C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302439 , vital:58196 , xlink:href="https://doi.org/10.1037/neu0000742"
- Description: Objective: Large-scale studies have revolutionized biomedical research, and neurocognitive tests can help elucidate the biological basis of neuropsychiatric diseases. However, studies have predominantly been conducted in Western settings. We describe the development and validation of a computerized battery (PennCNB) with the Xhosa population of South Africa. Method: Individuals with schizophrenia (n = 525) and a normative comparison group (n = 744) were balanced on age, sex, education, and region. Participants provided blood samples, were assessed psychiatrically, and were administered a PennCNB translation to isiXhosa, including measures of executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed. Feasibility was examined with test completion rates and input from administrators, and psychometric structural validity and associations with clinical and demographic characteristics were examined. Results: Tests were well tolerated by participants, as >87% had one (or fewer) test missing. Results suggested a similar factor structure to prior PennCNB studies in Western contexts, and expected age and sex effects were apparent. Furthermore, a similar profile of schizophrenia was observed, with neurocognitive deficits most pronounced for executive functions, especially attention, as well as memory, social cognition, and motor speed relative to complex cognition and sensorimotor speed. Conclusions: Results support the feasibility of implementing a culturally adapted computerized neurocognitive battery in sub-Saharan African settings and provide evidence supporting the concurrent validity of the translated instrument. Thus, the PennCNB is implementable on a large scale in non-Western contexts, shows expected factor structure, and can detect cognitive deficits associated with neuropsychiatric disorders. Obtaining valid measures of cognition by nonspecialized proctors is especially suitable in resource-limited settings, where traditional testing is prohibitive. Future work should establish normative standards, test–retest reliability, and sensitivity to treatment.
- Full Text:
- Date Issued: 2021
- Authors: Cobb, Scott J , Moore, Tyler M , Stein, Dan J , Pretorius, Adele , Zingela, Zukiswa , Nagdee, Mohammed , Ngqengelele, Linda , Campbell, Megan , Sibeko, Goodman , King, Mary C , McClellan, Jon M , Port, Allison M , Jackson, Chad , Ruparel, Kosha , Susser, Ezra , Gur, Ruben C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302439 , vital:58196 , xlink:href="https://doi.org/10.1037/neu0000742"
- Description: Objective: Large-scale studies have revolutionized biomedical research, and neurocognitive tests can help elucidate the biological basis of neuropsychiatric diseases. However, studies have predominantly been conducted in Western settings. We describe the development and validation of a computerized battery (PennCNB) with the Xhosa population of South Africa. Method: Individuals with schizophrenia (n = 525) and a normative comparison group (n = 744) were balanced on age, sex, education, and region. Participants provided blood samples, were assessed psychiatrically, and were administered a PennCNB translation to isiXhosa, including measures of executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed. Feasibility was examined with test completion rates and input from administrators, and psychometric structural validity and associations with clinical and demographic characteristics were examined. Results: Tests were well tolerated by participants, as >87% had one (or fewer) test missing. Results suggested a similar factor structure to prior PennCNB studies in Western contexts, and expected age and sex effects were apparent. Furthermore, a similar profile of schizophrenia was observed, with neurocognitive deficits most pronounced for executive functions, especially attention, as well as memory, social cognition, and motor speed relative to complex cognition and sensorimotor speed. Conclusions: Results support the feasibility of implementing a culturally adapted computerized neurocognitive battery in sub-Saharan African settings and provide evidence supporting the concurrent validity of the translated instrument. Thus, the PennCNB is implementable on a large scale in non-Western contexts, shows expected factor structure, and can detect cognitive deficits associated with neuropsychiatric disorders. Obtaining valid measures of cognition by nonspecialized proctors is especially suitable in resource-limited settings, where traditional testing is prohibitive. Future work should establish normative standards, test–retest reliability, and sensitivity to treatment.
- Full Text:
- Date Issued: 2021
Addressing the red flags in cochineal identification: The use of molecular techniques to identify cochineal insects that are used as biological control agents for invasive alien cacti
- van Steenderen, Clarke J M, Paterson, Iain D, Edwards, Shelley, Day, M D
- Authors: van Steenderen, Clarke J M , Paterson, Iain D , Edwards, Shelley , Day, M D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423282 , vital:72044 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104426"
- Description: Invasive Cactaceae cause considerable damage to ecosystem function and agricultural practices around the world. The most successful biological control agents used to combat this group of weeds belong to the genus Dactylopius (Hemiptera: Dactylopiidae), commonly known as ‘cochineal’. Effective control relies on selecting the correct species, or in some cases, the most effective intraspecific lineage, of cochineal for the target cactus species. Many of the Dactylopius species are so morphologically similar, and in the case of intraspecific lineages, identical, that numerous misidentifications have been made in the past. These errors have resulted in failed attempts at the biological control of some cactus species. This study aimed to generate a multi-locus genetic database to enable the accurate identification of dactylopiids. Genetic characterization was achieved through the nucleotide sequencing of three gene regions (12S rRNA, 18S rRNA, and COI) and two inter-simple sequence repeats (ISSR). Nucleotide sequences were very effective for species-level and D. tomentosus lineage-level identification, but could not distinguish between the two lineages within D. opuntiae commonly used for biological control of various Opuntia spp. Fragment analysis through the use of ISSRs successfully addressed this issue. This is the first time that a method has been developed that can distinguish between these two D. opuntiae lineages. Using the methods developed in this study, biological control practitioners can ensure that the most effective agent species and lineages are used for each cactus target weed, thus maximizing the level of control.
- Full Text:
- Date Issued: 2021
- Authors: van Steenderen, Clarke J M , Paterson, Iain D , Edwards, Shelley , Day, M D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423282 , vital:72044 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104426"
- Description: Invasive Cactaceae cause considerable damage to ecosystem function and agricultural practices around the world. The most successful biological control agents used to combat this group of weeds belong to the genus Dactylopius (Hemiptera: Dactylopiidae), commonly known as ‘cochineal’. Effective control relies on selecting the correct species, or in some cases, the most effective intraspecific lineage, of cochineal for the target cactus species. Many of the Dactylopius species are so morphologically similar, and in the case of intraspecific lineages, identical, that numerous misidentifications have been made in the past. These errors have resulted in failed attempts at the biological control of some cactus species. This study aimed to generate a multi-locus genetic database to enable the accurate identification of dactylopiids. Genetic characterization was achieved through the nucleotide sequencing of three gene regions (12S rRNA, 18S rRNA, and COI) and two inter-simple sequence repeats (ISSR). Nucleotide sequences were very effective for species-level and D. tomentosus lineage-level identification, but could not distinguish between the two lineages within D. opuntiae commonly used for biological control of various Opuntia spp. Fragment analysis through the use of ISSRs successfully addressed this issue. This is the first time that a method has been developed that can distinguish between these two D. opuntiae lineages. Using the methods developed in this study, biological control practitioners can ensure that the most effective agent species and lineages are used for each cactus target weed, thus maximizing the level of control.
- Full Text:
- Date Issued: 2021
Advances in the regulation of weed biological control in South Africa
- Ivey, Philip, Hill, Martin P, Zachariades, Costas
- Authors: Ivey, Philip , Hill, Martin P , Zachariades, Costas
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416819 , vital:71388 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a24"
- Description: Regulation of biological control (biocontrol) is essential to ensure its continued safety and to enhance its acceptability as a key contributor to the management of damaging invasive alien plants in South Africa. Local researchers were concerned that regulators may become risk averse and over-cautious, thus preventing introductions of safe biocontrol agents, as bureaucratic impediments have contributed to the decline in the number of biocontrol releases in several other countries. In South Africa, the introduction of a transparent and inclusive review process has averted these concerns. Legislation in South Africa enables departments concerned with protecting environmental and agricultural resources, to work together to regulate potential risks. An interdepartmental committee, advised by independent specialists, facilitate the review of research into the safety of potential biocontrol agents. Regulators have reviewed and timeously assessed 26 potential biocontrol agents between 2013 and 2020. This has ensured that the considerable benefits from safe biocontrol agents are available for management of some of South Africa’s worst invasive alien plants. We review the system in South Africa and suggest possible improvements to the regulatory framework.
- Full Text:
- Date Issued: 2021
- Authors: Ivey, Philip , Hill, Martin P , Zachariades, Costas
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416819 , vital:71388 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a24"
- Description: Regulation of biological control (biocontrol) is essential to ensure its continued safety and to enhance its acceptability as a key contributor to the management of damaging invasive alien plants in South Africa. Local researchers were concerned that regulators may become risk averse and over-cautious, thus preventing introductions of safe biocontrol agents, as bureaucratic impediments have contributed to the decline in the number of biocontrol releases in several other countries. In South Africa, the introduction of a transparent and inclusive review process has averted these concerns. Legislation in South Africa enables departments concerned with protecting environmental and agricultural resources, to work together to regulate potential risks. An interdepartmental committee, advised by independent specialists, facilitate the review of research into the safety of potential biocontrol agents. Regulators have reviewed and timeously assessed 26 potential biocontrol agents between 2013 and 2020. This has ensured that the considerable benefits from safe biocontrol agents are available for management of some of South Africa’s worst invasive alien plants. We review the system in South Africa and suggest possible improvements to the regulatory framework.
- Full Text:
- Date Issued: 2021
Aluminum corrosion retardation properties of acetamidophenoxy phthalocyanines: Effect of central metal
- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Date Issued: 2021
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Date Issued: 2021
Amphiphilic axially modified cationic indium-porphyrins linked to hydrophilic magnetic nanoparticles for photodynamic antimicrobial chemotherapy against gram-negative strain; Escherichia coli
- Makolla, Collen L, Mgidlana, Sithi, Nyokong, Tebello
- Authors: Makolla, Collen L , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185024 , vital:44317 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109262"
- Description: In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.
- Full Text:
- Date Issued: 2021
- Authors: Makolla, Collen L , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185024 , vital:44317 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109262"
- Description: In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.
- Full Text:
- Date Issued: 2021
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
Asymmetrical zinc (II) phthalocyanines cobalt tungstate nanomaterial conjugates for photodegradation of methylene blue
- Mgidlana, Sithi, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184991 , vital:44314 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113421"
- Description: Herein, we present syntheses of three asymmetrical zinc(II) phthalocyanine (ZnPc) complexes and hydrothermal synthesis of cobalt tungstate nanoparticles. The ZnPc derivatives were covalently linked to cobalt tungstate nanoparticles. Photophysical and photochemical behaviour of Pcs and nanoconjugates were investigated. The nanoconjugates generated higher triplet quantum yield and singlet oxygen quantum yield than the ZnPcs alone. Furthermore, in this paper photocatalytic efficiencies of ZnPc complexes and nanoconjugates were investigated for the degradation of methylene blue and higher photocatalytic behaviour was observed for the conjugates. The kinetic model was used to study photocatalytic behaviour of all the prepared photocatalysts.
- Full Text:
- Date Issued: 2021
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184991 , vital:44314 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113421"
- Description: Herein, we present syntheses of three asymmetrical zinc(II) phthalocyanine (ZnPc) complexes and hydrothermal synthesis of cobalt tungstate nanoparticles. The ZnPc derivatives were covalently linked to cobalt tungstate nanoparticles. Photophysical and photochemical behaviour of Pcs and nanoconjugates were investigated. The nanoconjugates generated higher triplet quantum yield and singlet oxygen quantum yield than the ZnPcs alone. Furthermore, in this paper photocatalytic efficiencies of ZnPc complexes and nanoconjugates were investigated for the degradation of methylene blue and higher photocatalytic behaviour was observed for the conjugates. The kinetic model was used to study photocatalytic behaviour of all the prepared photocatalysts.
- Full Text:
- Date Issued: 2021
Attitudes and preferences towards elements of formal and informal public green spaces in two South African towns
- Manyani, Amanda, Shackleton, Charlie M, Cocks, Michelle
- Authors: Manyani, Amanda , Shackleton, Charlie M , Cocks, Michelle
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402203 , vital:69830 , xlink:href="https://doi.org/10.1016/j.landurbplan.2021.104147"
- Description: Different types of public urban green spaces (PUGS) contain various natural (such as trees, pools, flowerbeds) and artificial elements (such as benches, play equipment, fountains) which contribute to the enjoyment and experience of users. However, which elements users most require, appreciate or notice has rarely been examined as the basis of their choice for specific PUGS, especially in poorer neighbourhoods and countries, where formal PUGS may be limited. The study was carried out in two towns in the Eastern Cape province of South Africa, both characterized by high poverty and unemployment levels, low literacy rates and many people living without basic infrastructure and services. To understand the meanings people, have for specific PUGS elements, formal and informal PUGS and peri-urban municipal commonages were assessed with respect to the natural and artificial elements present. A survey of 360 households was conducted across two towns by targeting PUGS users and households within 100 m from the designated PUGS. Approximately 63% of the respondents visited PUGS, with informal PUGS being the most frequented. However, they were strong negative feelings towards some natural elements because of their unkempt nature. Issues of safety, cultural restrictions and lack of recreational facilities were mentioned as some of the specific deterrents against visiting the closest PUGS among different user and age groups. Most respondents emphasized the need for PUGS that are well laid out with maintained lawns, recreational facilities and open vegetation. Thus, the current design and available features within the studied PUGS do not meet local preferences and needs and thus do not contribute to enjoyment as much as they could. Attention needs to be given to understand and incorporate the elements that invoke positive attitudes among urban residents.
- Full Text:
- Date Issued: 2021
- Authors: Manyani, Amanda , Shackleton, Charlie M , Cocks, Michelle
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402203 , vital:69830 , xlink:href="https://doi.org/10.1016/j.landurbplan.2021.104147"
- Description: Different types of public urban green spaces (PUGS) contain various natural (such as trees, pools, flowerbeds) and artificial elements (such as benches, play equipment, fountains) which contribute to the enjoyment and experience of users. However, which elements users most require, appreciate or notice has rarely been examined as the basis of their choice for specific PUGS, especially in poorer neighbourhoods and countries, where formal PUGS may be limited. The study was carried out in two towns in the Eastern Cape province of South Africa, both characterized by high poverty and unemployment levels, low literacy rates and many people living without basic infrastructure and services. To understand the meanings people, have for specific PUGS elements, formal and informal PUGS and peri-urban municipal commonages were assessed with respect to the natural and artificial elements present. A survey of 360 households was conducted across two towns by targeting PUGS users and households within 100 m from the designated PUGS. Approximately 63% of the respondents visited PUGS, with informal PUGS being the most frequented. However, they were strong negative feelings towards some natural elements because of their unkempt nature. Issues of safety, cultural restrictions and lack of recreational facilities were mentioned as some of the specific deterrents against visiting the closest PUGS among different user and age groups. Most respondents emphasized the need for PUGS that are well laid out with maintained lawns, recreational facilities and open vegetation. Thus, the current design and available features within the studied PUGS do not meet local preferences and needs and thus do not contribute to enjoyment as much as they could. Attention needs to be given to understand and incorporate the elements that invoke positive attitudes among urban residents.
- Full Text:
- Date Issued: 2021
Ball-type phthalocyanines and reduced graphene oxide nanoparticles as separate and combined corrosion inhibitors of aluminium in HCl
- Nnaji, Nnaemeka, Nawji, Njemuwa, Mack, John, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Nawji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185421 , vital:44385 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130279"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for reduced graphene oxide nanosheets (rGONS), tetrakis-[4,4′-((4-(benzo[d]thiazol-2-yl)-1,2-bis(phenoxy)] (diphthalocyaninato gallium (III) chloride) (2) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium(III) chloride) (1). Corrosion inhibition effects of rGONS, 1 and 2 were evaluated alone and in combination in 1.0 M hydrochloric acid solution using electrochemical techniques. The mechanism of aluminum corrosion inhibition revealed predominantly anodic character for rGONS and predominantly cathodic character for 1, 2, and conjugates with rGONS . The polarization technique gave inhibition efficiency values of 96.5% and 96.9% respectively for 1 and 2, which increased in the presence of rGONS to 97.4% and 98.1%, respectively, for the highest concentrations of 1 and 2. Scanning electron microscopy revealed effective metal surface protection by the inhibitors by formation of protective films.
- Full Text:
- Date Issued: 2021
- Authors: Nnaji, Nnaemeka , Nawji, Njemuwa , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185421 , vital:44385 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130279"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for reduced graphene oxide nanosheets (rGONS), tetrakis-[4,4′-((4-(benzo[d]thiazol-2-yl)-1,2-bis(phenoxy)] (diphthalocyaninato gallium (III) chloride) (2) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium(III) chloride) (1). Corrosion inhibition effects of rGONS, 1 and 2 were evaluated alone and in combination in 1.0 M hydrochloric acid solution using electrochemical techniques. The mechanism of aluminum corrosion inhibition revealed predominantly anodic character for rGONS and predominantly cathodic character for 1, 2, and conjugates with rGONS . The polarization technique gave inhibition efficiency values of 96.5% and 96.9% respectively for 1 and 2, which increased in the presence of rGONS to 97.4% and 98.1%, respectively, for the highest concentrations of 1 and 2. Scanning electron microscopy revealed effective metal surface protection by the inhibitors by formation of protective films.
- Full Text:
- Date Issued: 2021
Biological control of cactaceae in South Africa
- Paterson, Iain D, Klein, Hildegard, Muskett, Phillippa C, Griffith, Tamzin C, Mayonde, Samalesu, Mofokeng, Kedibone, Mnqeta, Zezethu, Venter, Nic
- Authors: Paterson, Iain D , Klein, Hildegard , Muskett, Phillippa C , Griffith, Tamzin C , Mayonde, Samalesu , Mofokeng, Kedibone , Mnqeta, Zezethu , Venter, Nic
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:71034 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a4"
- Description: Cactaceae are among the most problematic invasive alien plants in South Africa, posing serious negative consequences to agriculture and natural ecosystems. Fortunately, South Africa has a long and successful history of controlling cactus weeds using biological control (biocontrol). This paper reviews all the biocontrol programmes against invasive alien Cactaceae in South Africa, focusing on the decade since the last review published in 2011, up to, and including 2020. Biocontrol programmes against 16 target weeds are summarised, all of which rely on either the galling mealybug, Hypogeococcus sp. (Pseudococcidae), or various species or intraspecific lineages of cochineal insects (Dactylopius spp., Dactylopiidae) as agents. New agents are being considered for the three target weed species, Opuntia elata Salm-Dyck, Opuntia megapotamica Arechav. and Trichocereus spachianus (Lem.) Riccob., while permission to release a new agent against Cylindropuntia pallida (Rose) F.M. Knuth has recently been granted. The biocontrol agent, Dactylopius opuntiae (Cockrell) ‘stricta’, which has been utilised for the successful control of Opuntia stricta Haw., has shown some promise as an agent against one of the worst cactus weeds in the country, the North Cape/Free State variety of Opuntia engelmannii Salm-Dyck. Post-release monitoring and recent observations of the status of control for the 11 other cactus weeds, all of which have well-established agents, are provided. Taxonomic uncertainties and misidentifications of both target weeds and agents has been a constraint to biocontrol efforts, but this has been partially overcome through the use of genetic techniques. Biocontrol is particularly successful in controlling cactus weeds compared to most other taxonomic groups, and it is likely that past successes can be repeated with new target weeds. Mass-rearing and redistribution of agents are essential to gain the maximum possible benefit from cactus biocontrol agents, and recent increases in mass-rearing outputs have been beneficial.
- Full Text:
- Date Issued: 2021
- Authors: Paterson, Iain D , Klein, Hildegard , Muskett, Phillippa C , Griffith, Tamzin C , Mayonde, Samalesu , Mofokeng, Kedibone , Mnqeta, Zezethu , Venter, Nic
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:71034 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a4"
- Description: Cactaceae are among the most problematic invasive alien plants in South Africa, posing serious negative consequences to agriculture and natural ecosystems. Fortunately, South Africa has a long and successful history of controlling cactus weeds using biological control (biocontrol). This paper reviews all the biocontrol programmes against invasive alien Cactaceae in South Africa, focusing on the decade since the last review published in 2011, up to, and including 2020. Biocontrol programmes against 16 target weeds are summarised, all of which rely on either the galling mealybug, Hypogeococcus sp. (Pseudococcidae), or various species or intraspecific lineages of cochineal insects (Dactylopius spp., Dactylopiidae) as agents. New agents are being considered for the three target weed species, Opuntia elata Salm-Dyck, Opuntia megapotamica Arechav. and Trichocereus spachianus (Lem.) Riccob., while permission to release a new agent against Cylindropuntia pallida (Rose) F.M. Knuth has recently been granted. The biocontrol agent, Dactylopius opuntiae (Cockrell) ‘stricta’, which has been utilised for the successful control of Opuntia stricta Haw., has shown some promise as an agent against one of the worst cactus weeds in the country, the North Cape/Free State variety of Opuntia engelmannii Salm-Dyck. Post-release monitoring and recent observations of the status of control for the 11 other cactus weeds, all of which have well-established agents, are provided. Taxonomic uncertainties and misidentifications of both target weeds and agents has been a constraint to biocontrol efforts, but this has been partially overcome through the use of genetic techniques. Biocontrol is particularly successful in controlling cactus weeds compared to most other taxonomic groups, and it is likely that past successes can be repeated with new target weeds. Mass-rearing and redistribution of agents are essential to gain the maximum possible benefit from cactus biocontrol agents, and recent increases in mass-rearing outputs have been beneficial.
- Full Text:
- Date Issued: 2021
Biological control of invasive climbing plants in South Africa
- King, Anthony M, Paterson, Iain D, Simelane, David O, Mawela, Khethani V, Mngeta, Zezethu
- Authors: King, Anthony M , Paterson, Iain D , Simelane, David O , Mawela, Khethani V , Mngeta, Zezethu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/413471 , vital:71041 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a17"
- Description: Vines and other climbing plants typically invest their resources into growth at the expense of accumulating self-supporting biomass. Adaptive traits that have arisen because of the life history needs of climbing species, such as rapid and extensive growth, as well as resilience to physical damage, make these plants highly competitive. Introduced climbing species therefore have the potential to be particularly damaging in novel ranges where they escape pressure from natural enemies. In South Africa, invasive climbing species negatively influence biodiversity and plant-community structure, and as conventional management is often difficult, biological control (biocontrol) is viewed as the only viable long-term control method. This paper consolidates the work done on biocontrol programmes against climbing species in South Africa, including Anredera cordifolia (Ten.) Steenis (Basellaceae), Cardiospermum grandiflorum Sw. (Sapindaceae), Dolichandra unguis-cati (L.) L.G.Lohmann (Bignoniaceae) and Pereskia aculeata Miller (Cactaceae). To date, these programmes have investigated some 27 potential biocontrol agents, of which nine have been approved for release in the country. Since 2010, three new agents have been introduced, and considerable progress made with post-release evaluations of all the introduced agents. Some positive results have been achieved, most notably the successful reduction in seed set of C. grandiflorum due to Cissanthonomus tuberculipennis Hustache (Curculionidae), but considerable variation in efficacy over time and between infestations has been recorded for many of the other agents. Further work may help explain the factors limiting success, leading to improved control, but in some cases, such as for A. cordifolia, new biocontrol agents should be considered.
- Full Text:
- Date Issued: 2021
- Authors: King, Anthony M , Paterson, Iain D , Simelane, David O , Mawela, Khethani V , Mngeta, Zezethu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/413471 , vital:71041 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a17"
- Description: Vines and other climbing plants typically invest their resources into growth at the expense of accumulating self-supporting biomass. Adaptive traits that have arisen because of the life history needs of climbing species, such as rapid and extensive growth, as well as resilience to physical damage, make these plants highly competitive. Introduced climbing species therefore have the potential to be particularly damaging in novel ranges where they escape pressure from natural enemies. In South Africa, invasive climbing species negatively influence biodiversity and plant-community structure, and as conventional management is often difficult, biological control (biocontrol) is viewed as the only viable long-term control method. This paper consolidates the work done on biocontrol programmes against climbing species in South Africa, including Anredera cordifolia (Ten.) Steenis (Basellaceae), Cardiospermum grandiflorum Sw. (Sapindaceae), Dolichandra unguis-cati (L.) L.G.Lohmann (Bignoniaceae) and Pereskia aculeata Miller (Cactaceae). To date, these programmes have investigated some 27 potential biocontrol agents, of which nine have been approved for release in the country. Since 2010, three new agents have been introduced, and considerable progress made with post-release evaluations of all the introduced agents. Some positive results have been achieved, most notably the successful reduction in seed set of C. grandiflorum due to Cissanthonomus tuberculipennis Hustache (Curculionidae), but considerable variation in efficacy over time and between infestations has been recorded for many of the other agents. Further work may help explain the factors limiting success, leading to improved control, but in some cases, such as for A. cordifolia, new biocontrol agents should be considered.
- Full Text:
- Date Issued: 2021
Biological control of South African plants that are invasive elsewhere in the world: A review of earlier and current programmes
- Olckers, Terence, Coetzee, Julie A, Egli, Daniella, Martin, Grant D, Paterson, Iain D, Sutton, Guy F, Wood, Alan
- Authors: Olckers, Terence , Coetzee, Julie A , Egli, Daniella , Martin, Grant D , Paterson, Iain D , Sutton, Guy F , Wood, Alan
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414336 , vital:71137 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a21"
- Description: South Africa supports a rich floral diversity, with 21 643 native plant taxa that include a high proportion (76.3%) of endemic species, and many of these favoured as ornamentals, both locally and globally. Consequently, South Africa has contributed substantially to global plant invasions, with 1093 native taxa (5% of all species) naturalized in other countries. At least 80 taxa are invasive in natural or semi-natural ecosystems elsewhere, while an additional 132 taxa are potentially invasive. Of the global naturalized flora, 8.2% originate from South Africa and largely comprise species of Poaceae, Asteraceae, Iridaceae and Fabaceae. Australia, in particular, but also Europe and North America are major recipients of South African weeds. However, few countries have targeted South African plants for biological control (biocontrol), with most efforts undertaken by Australia. Previous and current targets have involved only 26 species with 17 agents (15 insects, one mite and one rust fungus) of South African origin released on five target species in Australia and the United States of America. South Africa’s history of weed biocontrol, together with a large cohort of active scientists, is currently facilitating several internationally funded programmes targeting invasive plants of South African origin. In particular, the recently inaugurated Centre for Biological Control at Rhodes University and the University of KwaZulu-Natal have provided the impetus for novel efforts on five new target species and renewed efforts on four previously targeted species. In this contribution, we review the history of earlier biocontrol programmes against weeds of South African origin and the status of projects currently in progress in South Africa.
- Full Text:
- Date Issued: 2021
- Authors: Olckers, Terence , Coetzee, Julie A , Egli, Daniella , Martin, Grant D , Paterson, Iain D , Sutton, Guy F , Wood, Alan
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414336 , vital:71137 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a21"
- Description: South Africa supports a rich floral diversity, with 21 643 native plant taxa that include a high proportion (76.3%) of endemic species, and many of these favoured as ornamentals, both locally and globally. Consequently, South Africa has contributed substantially to global plant invasions, with 1093 native taxa (5% of all species) naturalized in other countries. At least 80 taxa are invasive in natural or semi-natural ecosystems elsewhere, while an additional 132 taxa are potentially invasive. Of the global naturalized flora, 8.2% originate from South Africa and largely comprise species of Poaceae, Asteraceae, Iridaceae and Fabaceae. Australia, in particular, but also Europe and North America are major recipients of South African weeds. However, few countries have targeted South African plants for biological control (biocontrol), with most efforts undertaken by Australia. Previous and current targets have involved only 26 species with 17 agents (15 insects, one mite and one rust fungus) of South African origin released on five target species in Australia and the United States of America. South Africa’s history of weed biocontrol, together with a large cohort of active scientists, is currently facilitating several internationally funded programmes targeting invasive plants of South African origin. In particular, the recently inaugurated Centre for Biological Control at Rhodes University and the University of KwaZulu-Natal have provided the impetus for novel efforts on five new target species and renewed efforts on four previously targeted species. In this contribution, we review the history of earlier biocontrol programmes against weeds of South African origin and the status of projects currently in progress in South Africa.
- Full Text:
- Date Issued: 2021
Book Review Quinn, L.(ed.) 2019. Re-imagining Curriculum: Spaces for Disruption
- Authors: McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185865 , vital:44441 , xlink:href="https://journals.co.za/doi/abs/10.14426/cristal.v9i1.434"
- Description: This book is in some ways a continuation of the conversation begun with Reimaging Academic Staff Development: Spaces for Disruption (2012), also edited by Lynn Quinn. But the 2019 volume takes a much wider viewpoint including, as it does, twenty chapters by forty-two authors who are academics and academic developers across institutional types from Australia, Canada, South Africa, the United States of America, the United Kingdom, and the West Indies. Quinn and Vorster (2019: 2) state in Chapter One that the purpose of the book is 'to share theoretical perspectives and practical ideas for ways in which academic developers (and academic leaders) can work in partnership with lecturers and students to respond to the urgent calls for curriculum transformation and decolonisation'. This captures the four threads that run throughout the collection.
- Full Text:
- Date Issued: 2021
- Authors: McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185865 , vital:44441 , xlink:href="https://journals.co.za/doi/abs/10.14426/cristal.v9i1.434"
- Description: This book is in some ways a continuation of the conversation begun with Reimaging Academic Staff Development: Spaces for Disruption (2012), also edited by Lynn Quinn. But the 2019 volume takes a much wider viewpoint including, as it does, twenty chapters by forty-two authors who are academics and academic developers across institutional types from Australia, Canada, South Africa, the United States of America, the United Kingdom, and the West Indies. Quinn and Vorster (2019: 2) state in Chapter One that the purpose of the book is 'to share theoretical perspectives and practical ideas for ways in which academic developers (and academic leaders) can work in partnership with lecturers and students to respond to the urgent calls for curriculum transformation and decolonisation'. This captures the four threads that run throughout the collection.
- Full Text:
- Date Issued: 2021
Borneol-triarylcorrole hybrids with chiral-optical response and anticancer behaviours
- Fu, Bo, Wang, Lin, Yu, Xiaoxiao, Fang, Xianying, Mack, John, Dingiswayo, Somila, Nyokong, Tebello, Liang, Xu, Xu, Haijun
- Authors: Fu, Bo , Wang, Lin , Yu, Xiaoxiao , Fang, Xianying , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu , Xu, Haijun
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185294 , vital:44362 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109699"
- Description: A series of four multifunctional A2B type H3corroles with meso-borneol substituents at the B position have been synthesized and characterized. A detailed analysis of the optical properties was carried out, and a comparison was made with theoretical calculations to identify the key trends in the structure-property relationships. The meso-borneol substituent couples with the corrole core leading to clear CD signals in the B band region. Enhanced anti-cancer properties are observed in vitro relative to (−)-borneol with cell inhibition rates of up to 94%.
- Full Text:
- Date Issued: 2021
- Authors: Fu, Bo , Wang, Lin , Yu, Xiaoxiao , Fang, Xianying , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu , Xu, Haijun
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185294 , vital:44362 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109699"
- Description: A series of four multifunctional A2B type H3corroles with meso-borneol substituents at the B position have been synthesized and characterized. A detailed analysis of the optical properties was carried out, and a comparison was made with theoretical calculations to identify the key trends in the structure-property relationships. The meso-borneol substituent couples with the corrole core leading to clear CD signals in the B band region. Enhanced anti-cancer properties are observed in vitro relative to (−)-borneol with cell inhibition rates of up to 94%.
- Full Text:
- Date Issued: 2021
Bridging through “women’s work"
- Authors: Magadla, Siphokazi
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298650 , vital:57724 , xlink:href="https://doi.org/10.1080/14616742.2020.1863158"
- Description: Bodomo’s bridge theory describes and predicts the long-term implications of African migrants’ activities and settlement in China. Drawing on research with African retail traders, university students, and corporate executives in China, I show that the bridge theory illuminates how African women and men rationalize their decisions to migrate to China within the context of the rise of Asia. Drawing on the literature regarding African women and work, I explain that structural economic conditions now force more Africans into economic sectors such as trade work that historically were dominated by African women. I demonstrate that African women’s roles as economic providers for their families and children in other sectors, such as university students and company executives, provide evidence of the continued “matricentric” nature of African households that rely on women’s economic productivity. I also examine the possibilities and limitations of building long-standing networks that shape African migrant settlement in China. I show that the historical theorization that characterizes global mobility as male – particularly regarding Africans – has contributed to the misrecognition of African women’s multiple activities in China.
- Full Text:
- Date Issued: 2021
- Authors: Magadla, Siphokazi
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298650 , vital:57724 , xlink:href="https://doi.org/10.1080/14616742.2020.1863158"
- Description: Bodomo’s bridge theory describes and predicts the long-term implications of African migrants’ activities and settlement in China. Drawing on research with African retail traders, university students, and corporate executives in China, I show that the bridge theory illuminates how African women and men rationalize their decisions to migrate to China within the context of the rise of Asia. Drawing on the literature regarding African women and work, I explain that structural economic conditions now force more Africans into economic sectors such as trade work that historically were dominated by African women. I demonstrate that African women’s roles as economic providers for their families and children in other sectors, such as university students and company executives, provide evidence of the continued “matricentric” nature of African households that rely on women’s economic productivity. I also examine the possibilities and limitations of building long-standing networks that shape African migrant settlement in China. I show that the historical theorization that characterizes global mobility as male – particularly regarding Africans – has contributed to the misrecognition of African women’s multiple activities in China.
- Full Text:
- Date Issued: 2021
Constraints on improving higher education teaching and learning through funding
- Authors: Moyo, Temwa , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185854 , vital:44440 , xlink:href="http://dx.doi.org/10.17159/sajs.2021/7807"
- Description: In the midst of massification, targeted funding has been used in various countries to address inefficiencies in teaching and learning. In South Africa, arguments have been made for significant investments to be made and the University Capacity Development Grant (UCDG) in particular is being used as a driver for improved outputs. Prior to its implementation in 2018, the UCDG comprised the Research Development Grant and the Teaching Development Grant. The Teaching Development Grant was intended to address low retention and throughput rates and ZAR5.5 billion was spent to this end over a 12-year period. The analysis presented here of all Teaching Development Grant budget plans and progress reports from 2007 to 2015 shows that the undifferentiated implementation of the Teaching Development Grant within a differentiated sector limited its potential for system-wide gains. Institutions without adequate resources tended to divert Teaching Development Grant funds to attend to backlogs rather than to address teaching and learning practices and such universities lost much of their allocation through the withholding of unspent funds. This blanket practice addressed the symptoms of underspending but not the structural, cultural and agential mechanisms that led to such under-expenditure. Uneven access to the limited teaching development expertise also impacted on the use of the grant. This call for a context-based approach to funding has been identified as a key success factor in grant interventions in both African and European universities. We recommend a sector-wide response in the form of a national body or plan for the benefit of all universities and investment in financial management enhancement. The study contributes to a better understanding of how government funding interventions can achieve intended goals. The study calls for a more contextualised approach to funding and to greater collaboration across the sector to maximise limited capacity.
- Full Text:
- Date Issued: 2021
- Authors: Moyo, Temwa , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185854 , vital:44440 , xlink:href="http://dx.doi.org/10.17159/sajs.2021/7807"
- Description: In the midst of massification, targeted funding has been used in various countries to address inefficiencies in teaching and learning. In South Africa, arguments have been made for significant investments to be made and the University Capacity Development Grant (UCDG) in particular is being used as a driver for improved outputs. Prior to its implementation in 2018, the UCDG comprised the Research Development Grant and the Teaching Development Grant. The Teaching Development Grant was intended to address low retention and throughput rates and ZAR5.5 billion was spent to this end over a 12-year period. The analysis presented here of all Teaching Development Grant budget plans and progress reports from 2007 to 2015 shows that the undifferentiated implementation of the Teaching Development Grant within a differentiated sector limited its potential for system-wide gains. Institutions without adequate resources tended to divert Teaching Development Grant funds to attend to backlogs rather than to address teaching and learning practices and such universities lost much of their allocation through the withholding of unspent funds. This blanket practice addressed the symptoms of underspending but not the structural, cultural and agential mechanisms that led to such under-expenditure. Uneven access to the limited teaching development expertise also impacted on the use of the grant. This call for a context-based approach to funding has been identified as a key success factor in grant interventions in both African and European universities. We recommend a sector-wide response in the form of a national body or plan for the benefit of all universities and investment in financial management enhancement. The study contributes to a better understanding of how government funding interventions can achieve intended goals. The study calls for a more contextualised approach to funding and to greater collaboration across the sector to maximise limited capacity.
- Full Text:
- Date Issued: 2021