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Development of a translation device for axiological-semantic density in political news articles: Wording and charging

  • Authors: Siebörger, Ian , Adendorff, Ralph D
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/385311 , vital:68006 , xlink:href="https://doi.org/10.1515/text-2020-0156"
  • Description: The concept of axiological-semantic density from Legitimation Code Theory (LCT) is extremely helpful in analysing political knowledge-building, as it describes the strength of relations between various people, political stances and moral judgements, enabling these to be positioned in relation to each other. We present a multi-level translation device designed to identify strengths of axiological-semantic density in political news articles from the Daily Sun, South Africa’s most popular tabloid newspaper. This translation device was devised through analysis of selected texts from a corpus of 516 articles published between January and June 2015. It was developed through a collaborative process involving the first author and a team of student research assistants. The final translation device has five tools, of which two, the wording and charging tools, are described in this article, and then illustrated using an example analysis of a Daily Sun political news article. Both tools reveal insights into South African political discourses and ways in which axiological-semantic density can be enacted in future research. Making axiological-semantic density visible using such a translation device also has practical applications in assisting readers to understand the ways in which publications such as the Daily Sun position political parties, enabling them to engage more constructively in discussions on the country’s future.
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  • Date Issued: 2023

Distribution and impact of the Asian seed beetle, Megabruchidius tonkineus (Pic, 1904)(Coleoptera: Chrysomelidae: Bruchinae) on Gleditsia triacanthos L. seeds in South Africa

  • Authors: Salgado, Sara E , Martin, Grant D
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452266 , vital:75116 , http://dx.doi.org/10.17159/2254-8854/2023/a13386
  • Description: Honey locust, Gleditsia triacanthos (Fabaceae) is a fast-growing deciduous tree native to North America. The tree has been introduced worldwide and has become invasive in South Africa. In 2017, it was listed as one of the nine fastest-spreading weeds in South Africa. Once established, it competes with and displaces indigenous species and dense stands can significantly reduce stream flow. The Asian seed-feeding bruchid, Megabruchidius tonkineus (Coleoptera: Chrysomelidae: Bruchinae) was introduced into South Africa and has subsequently taken honey locust as a host plant. The beetle damages honey locust seeds and is therefore considered a biological control agent, despite no host-specificity or impact studies having been conducted. This study shows that M. tonkineus has established across the entire G. triacanthos population range in South Africa, damaging approximately 9% of seeds. Laboratory studies show that M. tonkineus completes its larval development in the seeds of G. triacanthos in about 66.80±0.69 SE days before emerging. This study is the first to describe the distribution and impact of this alien insect in South Africa.
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  • Date Issued: 2023

Distribution and impact of the native South African wasp, Megastigmus transvaalensis (Hussey, 1956)(Hymenoptera: Torymidae) on the invasive Schinus terebinthifolia Raddi (Anacardiaceae) in South Africa

  • Authors: Mangenlele, Nwabisa L , Martin, Grant D
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/416841 , vital:71390 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a12"
  • Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a tree native to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis (Hussey, 1956) (Hymenoptera: Torymidae). The wasp’s native hosts are from the Searsia F.A. Barkley genus (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative Schinus molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis was found at nearly all the S. terebinthifolia populations in South Africa, but due to the limited number of predated seeds it is unlikely to reduce population sizes or curb the spread of the invasive alien tree in South Africa.
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  • Date Issued: 2023

Diverse values of nature for sustainability

Do thermal requirements of Dichrorampha odorata, a shoot-boring moth for the biological control of Chromolaena odorata, explain its failure to establish in South Africa?

  • Authors: Nqayi, Slindile B , Zachariades, Costas , Coetzee, Julie A , Hill, Martin P , Chidawanyika, Frank , Uyi, Osariyekemwen O , McConnachie, Andrew J
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/416851 , vital:71391 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a14"
  • Description: Chromolaena odorata (L.) RM King and H Rob. (Asteraceae) has been subject to a biological control programme in South Africa for over three decades. A shoot-tip boring moth, Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), originating from Jamaica, was released as a biological control agent in 2013 but despite the release of substantial numbers of the insect, it has not established a permanent field population. Because climate incompatibility is a major constraint for classical biological control of invasive plants, and based on the differences in climate between Jamaica and South Africa and field observations at release sites, aspects of the thermal physiology of D. odorata were investigated to elucidate reasons for its failure to establish. Developmental time decreased with increasing temperatures ranging from 20 °C to 30 °C, with incomplete development for immature stages at 18 °C and 32 °C. The developmental threshold, t, was calculated as 8.45 °C with 872.4 degree-days required to complete development (K). A maximum of 6.5 generations per year was projected for D. odorata in South Africa, with the heavily infested eastern region of the country being the most eco-climatically suitable for establishment. The lower lethal temperature (LLT50) of larvae and adults was –4.5 and 1.8 °C, respectively. The upper lethal temperature (ULT50) for larvae was 39.6 °C whilst that of adults was 41.0 °C. Larvae thus had better cold tolerance compared to adults whereas adults had better heat tolerance compared to larvae. The critical thermal (CT) limits for adults were 3.4 ± 0.07 to 43.7 ± 0.12 °C. Acclimation at 20 °C for 7 days resulted in increased cold and heat tolerance with a CTmin and CTmax of 1.9 ± 0.06 and 44.4 ± 0.07 °C respectively, compared to the relative control, acclimated at 25 °C. Acclimation at 30 °C improved neither cold (CTmin: 5.9 ± 0.08 °C) nor heat tolerance (CTmax: 42.9 ± 0.10 °C). These results suggest that thermal requirements fall within field temperatures and are thus not the main constraining factor leading to poor establishment of D. odorata in South Africa.
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  • Date Issued: 2023

Dual action of asymmetrical zinc (II) phthalocyanines conjugated to silver tungstate nanoparticles towards photodegradation of tetracycline and inactivation of Staphylococcus aureus bacteria

  • Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
  • Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
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  • Date Issued: 2023

Electrocatalytic Behavior of Manganese and Cobalt Porphyrins Attached to Graphene Quantum Dots: Applied in the Oxidation of Hydrazine

  • Authors: Jokazi, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/360411 , vital:65086 , xlink:href="https://doi.org/10.1002/elan.202200222"
  • Description: Manganese and cobalt metalated 5, 10, 15-tris(aminophenyl)-20-(4-carboxyphenyl) porphyrins (ClMnTA3CPP and CoTA3CPP) were synthesized and attached to graphene quantum dots (GQDs) via π-π interaction and electrostatic interaction. The electrochemical oxidation of hydrazine was performed via cyclic voltammetry and chronoamperometry. The CoTA3CPP showed good electrocatalytic activity towards the oxidation of hydrazine in terms of catalytic rate constants and limits of detection (LoD). ClMnTA3CPP showed lower overpotential 0.60 V. The introduction of GQDs improved the electrocatalytic ability when combined with CoTA3CPP and ClMnTA3CPP with the lowest LoD (0.0025 mM CoTA3CPP–GQDs) followed by ClMnTA3CPP–GQDs with 0.0033 mM.
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  • Date Issued: 2023

Enhancing Object Audio Control within an Immersive Sound System

  • Authors: Klingebiel, Lukas , Foss, Richard
  • Date: 2023
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/426771 , vital:72390 , https://ieeexplore.ieee.org/abstract/document/10289235
  • Description: Real time control over sound source positioning and movement is a primary advantage of object-based sound systems over channel-based systems. This paper describes a controller, processing engine, and associated library that enhances this object control. Apart from graphic spatialization control, the controller allows, for each object, the selection of its rendering algorithm, distance-based level, high frequency attenuation, reverb parameters and speaker isolation or locking. OSC control within the controller enables further control options.
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  • Date Issued: 2023

Entomopathogenic fungi associated with cultivated honeybush, Cyclopia spp., in South Africa and their pathogenicity towards a leafhopper pest, Molopopterus sp.(Hemiptera: Cicadellidae)

  • Authors: Mushore, Tapiwa G , Coombes, Candice A , Hill, Martin P
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/451382 , vital:75045 , http://dx.doi.org/10.17159/2254-8854/2023/a14183
  • Description: The southern and eastern parts of the African Fynbos region favour the production of honeybush tea. Honeybush biomass and extracts are used to prepare a beverage both locally and internationally, mainly as herbal tea with health benefits. Honeybush tea is mostly grown organically requiring natural control measures for pests and diseases. The leafhopper, Molopopterus sp., is one of the most important pests of cultivated honeybush in South Africa, as its feeding compromises the quality and quantity of the yield through leaf discolouration and reduction of the photosynthetic area. Local entomopathogenic fungi (EPF) can provide a pool of potential biocontrol agents for this pest. Therefore, a total of 98 soil samples were collected from organically grown honeybush fields and vegetation surrounding the honeybush fields in the Western Cape province of South Africa. Entomopathogenic fungi were isolated using the insect bait method and were characterised using molecular techniques. Twenty fungal isolates of Metarhizium anisopliae and Fusarium oxysporum were recovered from soil samples, of which 70% were from honeybush fields and 30% were from surrounding vegetation.
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  • Date Issued: 2023

Evaluating the establishment of a new water hyacinth biological control agent in South Africa

  • Authors: Miller, Benjamin E , Coetzee, Julie A , Hill, Martin P
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/451399 , vital:75046 , http://dx.doi.org/10.17159/2254-8854/2023/a15613
  • Description: Megamelus scutellaris Berg (Hemiptera: Delphacidae) is the most recent of nine biological control agents developed to manage invasive water hyacinth, Pontederia (= Eichhornia) crassipes Mart.(Pontederiaceae), in South Africa. More than a million M. scutellaris have been mass-reared and released since the first introduction of the agent into South Africa in 2013, successfully establishing overwintering populations at 32 sites in seven of the nine provinces. Establishment has also been recorded at seven of these sites through natural dispersal from sites where they had established. Inundative releases, where large numbers of M. scutellaris are released regularly, have resulted in excellent establishment, and caused a significant reduction in water hyacinth cover in areas where, historically, biological control seemed unlikely due to excessive eutrophication. Although M. scutellaris has established well throughout South Africa through classical biological control methods, this study also showed that inundative releases of biological control agents over multiple seasons results in the most effective control of the weed, especially at cool temperate and eutrophic sites.
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  • Date Issued: 2023

Evaluation of the antibacterial activity of gallic acid anchored phthalocyanine-doped silica nanoparticles towards Escherichia coli and Staphylococcus aureus biofilms and planktonic cells

  • Authors: Magadla, Aviwe , Openda, Yolande Ikala , Mpeta, Lekhetho S , Nyokong, Tebello
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/360424 , vital:65087 , xlink:href="https://doi.org/10.1016/j.pdpdt.2023.103520"
  • Description: In this work, we have described the synthesis of phthalocyanine complexes Zn(II) tetrakis 4-(5-formylpyridin-2-yl)oxy) phthalocyanine (2), Zn(II) tetrakis-1 butyl 4-(2-(6- (tetra-phenoxy)pyridin-3-yl) vinyl)pyridin-1-ium phthalocyanine (3) and Zn(II) tetrakis 1 butyl 5-(2-(1-butylpyridin-1-ium-4-yl)vinyl)-2-(tetra-phenoxy)pyridin-1-ium phthalocyanine (4). The effect of a varying number of charges when the Pc complexes are alone or grafted in gallic acid (GA) tagged silica nanoparticles on photodynamic antimicrobial chemotherapy (PACT) is investigated toward Staphylococcus aureus (S.aureus) and Escherichia coli (E.coli) in both planktonic and biofilm forms. Complex 4, bearing a total of 8 cationic charges, displayed the highest activity with log CFU (colony forming units) values of 8.60 and 6.42 against E.coli and S.aureus biofilms, respectively. The surface stability of E.coli and S.aureus biofilms in the presence of 4 and its conjugate was analyzed using cyclic voltammetry. Scanning electron microscopy (SEM) and Raman spectra are also used to study the conformational and biochemical changes within biofilm upon subjecting them to PACT.
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  • Date Issued: 2023

Feminism and women in African philosophy

  • Authors: Etieyibo, Edwin , Tabensky, Pedro
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/453305 , vital:75244 , https://doi.org/10.1080/02580136.2023.2283674
  • Description: In this preamble, we highlight some of the more recent work on gender and sexuality in African philosophy. We do this as a way of introducing the special issue on “African Philosophy, Women, and Feminism”. In particular, we outline and highlight the trajectory and intellectual landscape of several discussions on women and feminism in African philosophy in the issue, and in this way, build on some previous work on gender, women, sexuality and African philosophy.
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  • Date Issued: 2023

Fruits of the city: The nature, nurture and future of urban foraging

  • Authors: Sardeshpande, Mallika , Shackleton, Charlie M
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/402259 , vital:69835 , xlink:href="https://doi.org/10.1002/pan3.10428"
  • Description: Urban foraging is a global informal phenomenon which has been investigated in the Global North more than oth-er parts of the world. Characterising the nature of urban foraging in the Global South is imperative given the rapid urbanisation and sustainable development priorities in the region. In this study, we interviewed 80 urban forag-ers in four cities in the eastern coastal region of South Af-rica, with an aim to understand the nature of urban forag-ing in a developing nation context. We asked foragers about their initiation to and motivations for foraging, their logistics, yields and associated activities, descriptions of their foraging grounds, and if and how they had changed, and what they envisage as an ideal future for foraging.
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  • Date Issued: 2023

Governing pregnancy in the Global South: the case of post-apartheid South Africa

  • Authors: du Plessis, Ulandi , Macleod, Catriona I
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/441212 , vital:73867 , xlink:href="https://doi.org/10.1080/13698575.2023.2249943"
  • Description: Women who sell sex (WSS) are vulnerable to violence. We present a scoping review of the last decade of research on the prevalence and incidence of, factors associated with, and services regarding violence against WSS in Eastern and Southern African (ESA). A systematic search of various databases resulted in 20 papers being reviewed. Inclusion criteria, applied by the first two authors, were as follows: empirical papers, key research problem is violence against WSS, and conducted in ESA countries. The lifetime prevalence of violence revealed in the studies ranged from 21% to 82%. A pattern of generalized violence against WSS from paying clients, male partners, strangers, family members, friends/acquaintances, and the authorities emerged. Factors associated with violence included the context within which the sex work occurs, alcohol use, type of sex exchange interactions, and personal factors (low education, low income, marriage, youth, high client volume, time in sex work, forced sexual debut, and internalized sex work stigma). WSS seldom access services after violence. Evaluations of two programs, a woman-focused HIV intervention, and the Diagonal Interventions to Fast-Forward Reproductive Health project, showed improvements in gender-based violence services. Findings suggest that targeted programmes should be paired with improving general health services and focus on promoting collective agency among WSS.
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  • Date Issued: 2023

Historical diversification of Pseudonympha Wallengren, 1857 (Lepidoptera: Nymphalidae: Satyrinae).

  • Authors: van Steenderen, Clarke J M , Pringle, Ernest L , Villet, Martin H
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/442182 , vital:73965 , https://doi.org/10.1080/00222933.2023.2257373
  • Description: The butterfly genus Pseudonympha and several related genera are endemic to southern Africa. Although many of the species are montane, some inhabit the arid interior of South Africa, offering an opportunity to study the palaeobiogeography of this biome. Morphological data (for all species of Pseudonympha and allied African and Asian genera) and molecular data (WG and COI genes for nine of the 15 species of Pseudonympha and all of the southern African endemic genera of Ypthimina) were compiled. Phylogenetic analysis indicated that Pseudonympha apparently originated in the Cape Fold Mountains about 15 Mya ago and spread steadily eastwards and northwards along the Great Escarpment during the aridification of the region, perhaps assisted by orogeny in the east and oceanic cooling in the west. Aridification cycles seem to have intermittently isolated some early lineages in elevated habitats in the interior, so that those lineages show lower speciation rates (or perhaps higher extinction rates) than those in the east. Four species delineation techniques indicated that some species are taxonomically oversplit. Based on genetic polyphyly and morphological similarity, we propose that the status of P. swanepoeli be reduced to that of a subspecies of P. varii, such that all the north-eastern populations from Harrismith to Tzaneen fall under P. varii swanepoeli van Son stat. n., and all the southern populations fall under P. varii varii van Son stat. n. Ultimately, the diversification of both of these lineages seems tied to their host plants’ response to aridification brought on by continental drift and orogeny. Sympatric organisms (eg cicadas) with biologies focused around different resources (eg savanna trees) show other patterns of diversification. The phylogenetic analysis of the subtribe Ypthimina also supports the monophyly of Paternympha, paraphyly of Ypthima, recognition of Thymipa Moore stat. rev. as a phylogenetic independent genus, and new relationships for Strabena.
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  • Date Issued: 2023

History matters: Societal acceptance of deep-sea mining and incipient conflicts in Papua New Guinea

  • Authors: van Putten, Ingrid , Aswani, Shankar , Boonstra, W.J , De la Cruz-Modino, R , Das, Jewel , Glaser, Marion , Heck, Nadine , Narayan, Siddharth , Paytan, Adina , Selim, Samiya , Vave, Ron
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/391453 , vital:68653 , xlink:href="https://doi.org/10.1007/s40152-023-00318-0"
  • Description: New marine industries that develop and grow in response to the changing demand for their products have the potential to exert pressure on fragile marine environments. These emerging industries can benefit local communities but equally can have negative environmental and socio-cultural impacts. The development of new and emerging industries, like deep seabed mining (DSM), requires the acceptance and involvement of local communities. Yet, the history of marine exploitation is imbued with conflicts between industries and local communities. This paper presents a DSM case study in Papua New Guinea (PNG) to stimulate debate around the potential for conflict in the pursuit of resource extraction from the deep sea and the social and environmental harm that these extractions can cause. We do so by first presenting a timeline of local and extra-local events and enabling conditions that form the development background for the DSM Solwara 1 project in PNG. We then undertake a media narrative analysis to consider the contribution of aspects of social acceptability to this highly complex and multi-scale conflict. We find that the lack of (or a decrease in) social acceptability contributed to the conflict situation and ultimately the demise of the Solwara 1 project. Extra-locally, the initial development was positively framed around solutions for decarbonisation using new technology. Over time, actions by international NGOs, financial issues related to foreign companies, and asymmetry in the power balance between the Pacific Island nation and global businesses played a role in growing negative perceptions of acceptability. Historical experiences with prior environmental mining disasters, together with sea tenure governance challenges, and a lack of community and stakeholder acceptance also contributed to the demise of the project. Untangling and debating these complex interactions provides context and reasons for the tension between the lack of societal acceptance at a local scale and the perceived need for DSM products in the global North for innovative technologies and decarbonising societies. Better understanding these interactions and tensions can help emerging industries navigate a future blue economy.
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  • Date Issued: 2023

Host-specificity testing of the leaf-feeding flea beetle, Phenrica guerini, a biological control agent for the invasive alien cactus, Pereskia aculeata

  • Authors: Dixon, Elizabeth , Paterson, Iain D , Muskett, Phillippa C , McConnachie, Andrew
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/417687 , vital:71478 , xlink:href="https://doi.org/10.1080/09583157.2023.2214342"
  • Description: Pereskia aculeata Miller (Cactaceae) is an environmentally damaging invasive alien plant in South Africa and Australia. The flea-beetle, Phenrica guerini Bechyné (Coleoptera: Chrysomelidae), has been used in South Africa as a biological control agent against the plant for more than 30 years but updated host-specificity testing was required to determine its suitability as an agent in Australia. No-choice larval survival tests were conducted on 26 test plant species from 11 families, with survival to the adult stage only being recorded on the target weed, P. aculeata. No-choice oviposition testing with adult P. guerini was conducted on six test plant species. No adult feeding was recorded on any test plants and significantly more eggs were oviposited on P. aculeata (158.8 SE ± 21.4) than on Talinum caffrum (5.2 SE ± 5.2), which was the only test plant on which they oviposited. The adults survived on average 27 days longer on P. aculeata than on any test plant species. In a multiple-choice trial that included all three species that supported any larval feeding as well as P. aculeata, oviposition and feeding was only recorded on target weed. Phenrica guerini is suitably host specific for consideration in Australia as a biological control agent against P. aculeata.
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  • Date Issued: 2023

Impact of Access and Benefit Sharing implementation on biological control genetic resources

  • Authors: Mason, Peter G , Barratt, Barbara I P , Mc Kay, Fernando , Klapwijk, Johannette N , Silvestri, Luciano C , Hill, Martin P , Hinz, Hariet L , Sheppard, Andy , Brodeur, Jacques , Vitorino, Marcello Diniz , Weyl, Philip S R , Hoelmer, Kim A
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/418013 , vital:71501 , xlink:href="https://doi.org/10.1007/s10526-023-10176-8"
  • Description: The third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the use of genetic resources was further developed when the Nagoya Protocol on Access and Benefit Sharing came into effect in 2014. Interpretation of how this agreement is being implemented is wide-ranging and there are implications for biological control. A survey of biological control workers indicated that while some countries have facilitated access to biological control genetic resources, requirements in other countries have impeded biological control implementation. There was consensus that benefits to provider countries should be in the form of supporting local research communities. There was also agreement that the free use and exchange of biological control genetic resources has provided benefits to the global community, including to both providers and recipients of the agents. It is recommended that consideration of the free use and exchange principal should be a key element of Access and Benefit Sharing measures for the future.
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  • Date Issued: 2023

In silico substrate-binding profiling for SARS-CoV-2 Main protease (Mpro) using Hexapeptide substrates

  • Authors: Zabo, Sophakama , Lobb, Kevin A
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452711 , vital:75164 , xlink:href="https://doi.org/10.3390/v15071480"
  • Description: The SARS-CoV-2 main protease (Mpro) is essential for the life cycle of the COVID-19 virus. It cleaves the two polyproteins at 11 positions to generate mature proteins for virion formation. The cleavage site on these polyproteins is known to be Leu-Gln↓(Ser/Ala/Gly). A range of hexapeptides that follow the known sequence for recognition and cleavage was constructed using RDKit libraries and complexed with the crystal structure of Mpro (PDB ID 6XHM) through extensive molecular docking calculations. A subset of 131 of these complexes underwent 20 ns molecular dynamics simulations. The analyses of the trajectories from molecular dynamics included principal component analysis (PCA), and a method to compare PCA plots from separate trajectories was developed in terms of encoding PCA progression during the simulations. The hexapeptides formed stable complexes as expected, with reproducible molecular docking of the substrates given the extensiveness of the procedure. Only Lys-Leu-Gln*** (KLQ***) sequence complexes were studied for molecular dynamics. In this subset of complexes, the PCA analysis identified four classifications of protein motions across these sequences. KLQ*** complexes illustrated the effect of changes in substrate on the active site, with implications for understanding the substrate recognition of Mpro and informing the development of small molecule inhibitors.
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  • Date Issued: 2023

Inclusion complexation and liposomal encapsulation of an isoniazid hydrazone derivative in cyclodextrin for pH-dependent controlled release

  • Authors: Safari, Justin B , Mona, Lamine B , Sekaleli, Bafokeng T , Avudi, Bénite K , Isamura, Bienfait K , Mukubwa, Grady K , Salami, Sodeeq A , Mbinze, Jérémie K , Lobb, Kevin A , Krause, Rui W M , Nkanga, Christian I
  • Date: 2023
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/452727 , vital:75166 , xlink:href="https://doi.org/10.1016/j.jddst.2023.104302"
  • Description: Tuberculosis, a predominantly pulmonary pathology, is currently the deadliest infection worldwide. Its treatment is based on combination therapy involving selected antimicrobials including Isoniazid. However, physicochemical properties of isoniazid negatively affect the clinical performance of current tuberculosis regimens, causing drug resistance development and increasing mortality rates. Liposomal encapsulation improves antituberculosis drug delivery; however, nano-formulation of isoniazid remains challenging due to its small molecular size and high hydrophilicity. Therefore, this study aimed to derivatize isoniazid and formulate a controlled delivery system using the concept of drug-in-cyclodextrins-in-liposomes to enhance drug biopharmaceutical properties. A prodrug of isoniazid was synthesized and screened for its ability to form stable complexes with α, β, and γ cyclodextrins. A selected inclusion complex with β-cyclodextrin was encapsulated in liposomes and assessed for controlled release of isoniazid. Successful formation of a 1:1 complex was established and characterized, followed by molecular modeling studies to demonstrate strength of the interactions within the complex and predicted complex structure. The inclusion complex was successfully encapsulated in liposomes using the thin film hydration method and the ethanol injection ultrasonic dispersion, with the latter giving the best results. These findings demonstrate the potential.
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  • Date Issued: 2023
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