Inclusion complexation and liposomal encapsulation of an isoniazid hydrazone derivative in cyclodextrin for pH-dependent controlled release
- 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
- 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.
- Full Text:
- 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.
- Full Text:
Information extraction model from Ge’ez texts
- Gebeyehu, Seffi, Wolde, Worke, Shibeshi, Zelalem S
- Authors: Gebeyehu, Seffi , Wolde, Worke , Shibeshi, Zelalem S
- Date: 2023
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429176 , vital:72565 , 10.11591/ijeecs.v30.i2.pp787-795
- Description: Nowadays, voluminous and unstructured textual data is found on the Internet that could provide varied valuable information for different institutions such as health care, business-related, training, religion, culture, and history, among others. A such alarming growth of unstructured data fosters the need for various methods and techniques to extract valuable information from unstructured data. However, exploring helpful information to satisfy the needs of the stakeholders becomes a problem due to information overload via the internet. This paper, therefore, presents an effective model for extracting named entities from Ge'ez text using deep learning algorithms. A data set with a total of 5,270 sentences were used for training and testing purposes. Two experimental setups, i.e., long short-term memory (LSTM) and bidirectional long short-term memory (Bi-LSTM) were used to make an empirical evaluation with training and a testing split ratio of 80% to 20%, respectively. Experimental results showed that the proposed model could be a practical solution for building information extraction (IE) systems using Bi-LSTM, reaching a training, validation, and testing accuracy as high as 98.59%, 97.96%, and 96.21%, respectively. The performance evaluation results reflect a promising performance of the model compared with resource-rich languages such as English.
- Full Text:
- Authors: Gebeyehu, Seffi , Wolde, Worke , Shibeshi, Zelalem S
- Date: 2023
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429176 , vital:72565 , 10.11591/ijeecs.v30.i2.pp787-795
- Description: Nowadays, voluminous and unstructured textual data is found on the Internet that could provide varied valuable information for different institutions such as health care, business-related, training, religion, culture, and history, among others. A such alarming growth of unstructured data fosters the need for various methods and techniques to extract valuable information from unstructured data. However, exploring helpful information to satisfy the needs of the stakeholders becomes a problem due to information overload via the internet. This paper, therefore, presents an effective model for extracting named entities from Ge'ez text using deep learning algorithms. A data set with a total of 5,270 sentences were used for training and testing purposes. Two experimental setups, i.e., long short-term memory (LSTM) and bidirectional long short-term memory (Bi-LSTM) were used to make an empirical evaluation with training and a testing split ratio of 80% to 20%, respectively. Experimental results showed that the proposed model could be a practical solution for building information extraction (IE) systems using Bi-LSTM, reaching a training, validation, and testing accuracy as high as 98.59%, 97.96%, and 96.21%, respectively. The performance evaluation results reflect a promising performance of the model compared with resource-rich languages such as English.
- Full Text:
Inhibiting human dipeptidyl peptidase IV using cannabinoids and Leonotis leonurus extracts as a potential therapy for the management of diabetes
- Mkabayi, Lithalethu, Viljoen, Zenobia, Lobb, Kevin A, Pletschke, Brett I, Frost, Carminita L
- Authors: Mkabayi, Lithalethu , Viljoen, Zenobia , Lobb, Kevin A , Pletschke, Brett I , Frost, Carminita L
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452745 , vital:75167 , xlink:href="https://www.thieme-connect.com/products/ejournals/html/10.1055/s-0043-1773924"
- Description: Diabetes is a chronic metabolic disorder that has been shown to affect a growing number of people worldwide. Controlling blood glucose levels is one of the possible strategies to treat type 2 diabetes mellitus (T2DM). It has been established that the inhibition of dipeptidyl peptidase IV (DPP-IV) prolongs the activity of incretin hormones, which serve as key stimulators of insulin secretion and regulation of blood glucose levels. Although several synthetic DPP-IV inhibitors are available, there is still a need for naturally sourced inhibitors that have fewer to no undesirable side effects. In this study, cannabinoids and Leonotis leonurus aqueous extracts were evaluated for their inhibitory effects against recombinant human DPP-IV. Their potential inhibition mechanism was explored using in vitro and in silico approaches. All tested cannabinoids and L. leonurus aqueous extracts showed significant inhibitory activity against DPP-IV. Phytochemical analysis of L. leonurus extract indicated the presence of diterpenoids and alkaloids, which might contribute to the inhibitory activity. In molecular docking studies, among different constituents known in L. leonurus, luteolin and marrubiin showed binding energy of -7.2 kcal/mol and cannabinoids (cannabidiol, cannabigerol, cannabinol and Δ9-tetrahydrocannabinol) showed binding energies ranging from -6.5 to -8.2 kcal/mol. Molecular dynamics revealed that all tested compounds formed stable complexes with the enzyme during 100 ns simulation, indicating that they are good ligands. This study provided preliminary evidence for the potential application of the selected cannabinoids and L. leonurus in maintaining glucose homeostasis, suggesting that they could be suitable therapeutic candidates for managing T2DM.
- Full Text:
- Authors: Mkabayi, Lithalethu , Viljoen, Zenobia , Lobb, Kevin A , Pletschke, Brett I , Frost, Carminita L
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452745 , vital:75167 , xlink:href="https://www.thieme-connect.com/products/ejournals/html/10.1055/s-0043-1773924"
- Description: Diabetes is a chronic metabolic disorder that has been shown to affect a growing number of people worldwide. Controlling blood glucose levels is one of the possible strategies to treat type 2 diabetes mellitus (T2DM). It has been established that the inhibition of dipeptidyl peptidase IV (DPP-IV) prolongs the activity of incretin hormones, which serve as key stimulators of insulin secretion and regulation of blood glucose levels. Although several synthetic DPP-IV inhibitors are available, there is still a need for naturally sourced inhibitors that have fewer to no undesirable side effects. In this study, cannabinoids and Leonotis leonurus aqueous extracts were evaluated for their inhibitory effects against recombinant human DPP-IV. Their potential inhibition mechanism was explored using in vitro and in silico approaches. All tested cannabinoids and L. leonurus aqueous extracts showed significant inhibitory activity against DPP-IV. Phytochemical analysis of L. leonurus extract indicated the presence of diterpenoids and alkaloids, which might contribute to the inhibitory activity. In molecular docking studies, among different constituents known in L. leonurus, luteolin and marrubiin showed binding energy of -7.2 kcal/mol and cannabinoids (cannabidiol, cannabigerol, cannabinol and Δ9-tetrahydrocannabinol) showed binding energies ranging from -6.5 to -8.2 kcal/mol. Molecular dynamics revealed that all tested compounds formed stable complexes with the enzyme during 100 ns simulation, indicating that they are good ligands. This study provided preliminary evidence for the potential application of the selected cannabinoids and L. leonurus in maintaining glucose homeostasis, suggesting that they could be suitable therapeutic candidates for managing T2DM.
- Full Text:
International agreement for the use and exchange of classical biological control genetic resources: a practical proposal
- Mason, Peter G, Mc Kay, Fernando, Silvestri, Luciano C, Hill, Martin P, Weyl, Philip S R, Hinz, Hariet L, Brodeur, Jacques, Vitorino, Marcello Diniz, Barratt, Barbara I P
- Authors: Mason, Peter G , Mc Kay, Fernando , Silvestri, Luciano C , Hill, Martin P , Weyl, Philip S R , Hinz, Hariet L , Brodeur, Jacques , Vitorino, Marcello Diniz , Barratt, Barbara I P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418025 , vital:71502 , xlink:href="https://doi.org/10.1007/s10526-023-10177-7"
- Description: The Nagoya Protocol on Access and Benefit Sharing (ABS) was implemented to further develop the third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the utilization of genetic resources. Interpretation of this agreement is wide-ranging and there is concern that if ABS measures are poorly implemented biological control and the resultant public good will be greatly impeded. The ethos of multilateral use and exchange of genetic resources used in classical biological control will be particularly affected. In the spirit of the fair and equitable sharing of benefits arising out of the utilization of genetic resources, we propose a simple practical solution in the form of an international agreement on the use and exchange of classical biological control genetic resources.
- Full Text:
- Authors: Mason, Peter G , Mc Kay, Fernando , Silvestri, Luciano C , Hill, Martin P , Weyl, Philip S R , Hinz, Hariet L , Brodeur, Jacques , Vitorino, Marcello Diniz , Barratt, Barbara I P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418025 , vital:71502 , xlink:href="https://doi.org/10.1007/s10526-023-10177-7"
- Description: The Nagoya Protocol on Access and Benefit Sharing (ABS) was implemented to further develop the third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the utilization of genetic resources. Interpretation of this agreement is wide-ranging and there is concern that if ABS measures are poorly implemented biological control and the resultant public good will be greatly impeded. The ethos of multilateral use and exchange of genetic resources used in classical biological control will be particularly affected. In the spirit of the fair and equitable sharing of benefits arising out of the utilization of genetic resources, we propose a simple practical solution in the form of an international agreement on the use and exchange of classical biological control genetic resources.
- Full Text:
Know thy enemy: Investigating genetic contributions from putative parents of invasive Nymphaea mexicana hybrids in South Africa as part of efforts to develop biological control
- Reid, Megan K, Paterson, Iain D, Coetzee, Julie A, Gettys, Lyn A, Hill, Martin P
- Authors: Reid, Megan K , Paterson, Iain D , Coetzee, Julie A , Gettys, Lyn A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423540 , vital:72070 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105291"
- Description: Hybridisation of alien invasive plants complicates efforts to develop biological control, because variations in the genetic makeup of the target plant can impact the survival of host specific agents that have evolved adaptations specific to the original host. To maximise the likelihood of success in a biological control program, potential agents should therefore be collected from populations in the region of origin that are genetically similar to plants in the invaded range. Molecular markers are useful tools to understand genetic contributions in hybrid populations, especially where morphological differentiation is difficult. Nymphaea mexicana Zuccarini (Nymphaeaceae) is an invasive alien plant in South Africa that is being targeted for biological control, but hybrids with intermediate morphological traits are also present at several sites. In this study, ISSR (inter simple sequence repeats) and ITS (internal transcribed spacer) markers were used to determine which Nymphaea species are likely to be putative parents of these hybrids, and morphological characters were also investigated to determine if genetic and morphological traits matched. Two major hybrid groups were identified, with one group clustering with Nymphaea odorata Aiton and the other clustering with Nymphaea alba L. A third, smaller group clustered with Nymphaea tetragona Georgi, whereas the remaining samples clustered with pure N. mexicana from the native range. Morphological features agreed with deductions drawn from molecular data. These results allow us to focus efforts to find compatible biological control agents and better understand the complicated genetic structure of N. mexicana and Nymphaea hybrids in South Africa.
- Full Text:
- Authors: Reid, Megan K , Paterson, Iain D , Coetzee, Julie A , Gettys, Lyn A , Hill, Martin P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423540 , vital:72070 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105291"
- Description: Hybridisation of alien invasive plants complicates efforts to develop biological control, because variations in the genetic makeup of the target plant can impact the survival of host specific agents that have evolved adaptations specific to the original host. To maximise the likelihood of success in a biological control program, potential agents should therefore be collected from populations in the region of origin that are genetically similar to plants in the invaded range. Molecular markers are useful tools to understand genetic contributions in hybrid populations, especially where morphological differentiation is difficult. Nymphaea mexicana Zuccarini (Nymphaeaceae) is an invasive alien plant in South Africa that is being targeted for biological control, but hybrids with intermediate morphological traits are also present at several sites. In this study, ISSR (inter simple sequence repeats) and ITS (internal transcribed spacer) markers were used to determine which Nymphaea species are likely to be putative parents of these hybrids, and morphological characters were also investigated to determine if genetic and morphological traits matched. Two major hybrid groups were identified, with one group clustering with Nymphaea odorata Aiton and the other clustering with Nymphaea alba L. A third, smaller group clustered with Nymphaea tetragona Georgi, whereas the remaining samples clustered with pure N. mexicana from the native range. Morphological features agreed with deductions drawn from molecular data. These results allow us to focus efforts to find compatible biological control agents and better understand the complicated genetic structure of N. mexicana and Nymphaea hybrids in South Africa.
- Full Text:
Lessons learned from the translation of the Internalised Stigma of Mental Illness (ISMI) scale into isiXhosa for use with South African Xhosa people with schizophrenia
- Matshabane, Olivia P, Appelbaum, Paul S, Faure, Marlyn C, Marshall, Patricia A, Stein, Dan J, de Vries, Jantina, Campbell, Megan M
- Authors: Matshabane, Olivia P , Appelbaum, Paul S , Faure, Marlyn C , Marshall, Patricia A , Stein, Dan J , de Vries, Jantina , Campbell, Megan M
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/450689 , vital:74974 , xlink:href="https://doi.org/10.1177/13634615231168461"
- Description: Internalised stigma is highly prevalent among people with mental illness. This is concerning because internalised stigma is often associated with negative consequences affecting individuals’ personal, familial, social, and overall wellbeing, employment opportunities and recovery. Currently, there is no psychometrically validated instrument to measure internalised stigma among Xhosa people in their home language. Our study aimed to translate the Internalised Stigma of Mental Illness (ISMI) scale into isiXhosa. Following WHO guidelines, the ISMI scale was translated using a five-stage translation design which included (i) forward-translation, (ii) back-translation, (iii) committee approach, (iv) quantitative piloting, and (v) qualitative piloting using cognitive interviews. The ISMI isiXhosa version (ISMI-X) underwent psychometric testing to establish utility, within-scale validity, convergent, divergent, and content validity (assessed using frequency of endorsements and cognitive interviewing) with n = 65 Xhosa people with schizophrenia. The resultant ISMI-X scale demonstrated good psychometric utility, internal consistency for the overall scale (α = .90) and most subscales (α > .70, except the Stigma Resistance subscale where α = .57), convergent validity between the ISMI Discrimination Experiences subscale and the Discrimination and Stigma (DISC) scale's Treated Unfairly subscale (r = .34, p = .03) and divergent validity between the ISMI Stigma Resistance and DISC Treated Unfairly subscales (r = .13, p = .49). But more importantly the study provides valuable insights into strengths and limitations of the present translation design. Specifically, validation methods such as assessing frequency of endorsements of scale items and using cognitive interviewing to establish conceptual clarity and relevance of items may be useful in small piloting sample sizes.
- Full Text:
- Authors: Matshabane, Olivia P , Appelbaum, Paul S , Faure, Marlyn C , Marshall, Patricia A , Stein, Dan J , de Vries, Jantina , Campbell, Megan M
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/450689 , vital:74974 , xlink:href="https://doi.org/10.1177/13634615231168461"
- Description: Internalised stigma is highly prevalent among people with mental illness. This is concerning because internalised stigma is often associated with negative consequences affecting individuals’ personal, familial, social, and overall wellbeing, employment opportunities and recovery. Currently, there is no psychometrically validated instrument to measure internalised stigma among Xhosa people in their home language. Our study aimed to translate the Internalised Stigma of Mental Illness (ISMI) scale into isiXhosa. Following WHO guidelines, the ISMI scale was translated using a five-stage translation design which included (i) forward-translation, (ii) back-translation, (iii) committee approach, (iv) quantitative piloting, and (v) qualitative piloting using cognitive interviews. The ISMI isiXhosa version (ISMI-X) underwent psychometric testing to establish utility, within-scale validity, convergent, divergent, and content validity (assessed using frequency of endorsements and cognitive interviewing) with n = 65 Xhosa people with schizophrenia. The resultant ISMI-X scale demonstrated good psychometric utility, internal consistency for the overall scale (α = .90) and most subscales (α > .70, except the Stigma Resistance subscale where α = .57), convergent validity between the ISMI Discrimination Experiences subscale and the Discrimination and Stigma (DISC) scale's Treated Unfairly subscale (r = .34, p = .03) and divergent validity between the ISMI Stigma Resistance and DISC Treated Unfairly subscales (r = .13, p = .49). But more importantly the study provides valuable insights into strengths and limitations of the present translation design. Specifically, validation methods such as assessing frequency of endorsements of scale items and using cognitive interviewing to establish conceptual clarity and relevance of items may be useful in small piloting sample sizes.
- Full Text:
Local peoples’ knowledge and perceptions of Australian wattle (Acacia) species invasion, ecosystem services and disservices in grassland landscapes, South Africa
- Yapi, Thozamile S, Shackleton, Charlie M, Le Maitre, David C, Dziba, Luthando E
- Authors: Yapi, Thozamile S , Shackleton, Charlie M , Le Maitre, David C , Dziba, Luthando E
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399791 , vital:69559 , xlink:href="https://doi.org/10.1080/26395916.2023.2177495"
- Description: Many alien tree species were introduced into grassland ecosystems in South Africa by the commercial forestry industry for paper and timber for furniture. Over decades some of these introduced species escaped into neighbouring farms and community land. Adult trees from these alien species now provide other ecosystem services, notably fuelwood. Depending on the spatio-temporal context, many of these species can also negatively affect ecosystem services. We collected interview data from commercial and communal farmers in the upper Umzimvubu catchment in South Africa to compare farmers’ knowledge and perceptions of invasive wattle species invasion and their associated ecosystem services and disservices. Fuelwood and fencing poles were the most common uses of wattle by commercial (83%; 67%) and communal (99%; 49%) farmers. On the other hand, the reduction of grass cover and loss of grazing land were the most commonly mentioned negative impacts of wattles by commercial (83%; 75%) and communal (92%; 80%) farmers. Although both groups recognise the importance of wattles in providing ecosystem services, most communal farmers perceived wattles to have more negative effects than benefits. The findings demonstrate that both farmer groups highly depend on ecosystem services and are affected by disservices of wattles. However, while large-scale commercial households favour the presence of wattles in the landscape, communal households prefer complete removal of the wattles from the landscape. This may be due to lack of locally available alternative options or inability to replace or purchase ecosystem services affected by wattles from other sources or markets like commercial farmers.
- Full Text:
- Authors: Yapi, Thozamile S , Shackleton, Charlie M , Le Maitre, David C , Dziba, Luthando E
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399791 , vital:69559 , xlink:href="https://doi.org/10.1080/26395916.2023.2177495"
- Description: Many alien tree species were introduced into grassland ecosystems in South Africa by the commercial forestry industry for paper and timber for furniture. Over decades some of these introduced species escaped into neighbouring farms and community land. Adult trees from these alien species now provide other ecosystem services, notably fuelwood. Depending on the spatio-temporal context, many of these species can also negatively affect ecosystem services. We collected interview data from commercial and communal farmers in the upper Umzimvubu catchment in South Africa to compare farmers’ knowledge and perceptions of invasive wattle species invasion and their associated ecosystem services and disservices. Fuelwood and fencing poles were the most common uses of wattle by commercial (83%; 67%) and communal (99%; 49%) farmers. On the other hand, the reduction of grass cover and loss of grazing land were the most commonly mentioned negative impacts of wattles by commercial (83%; 75%) and communal (92%; 80%) farmers. Although both groups recognise the importance of wattles in providing ecosystem services, most communal farmers perceived wattles to have more negative effects than benefits. The findings demonstrate that both farmer groups highly depend on ecosystem services and are affected by disservices of wattles. However, while large-scale commercial households favour the presence of wattles in the landscape, communal households prefer complete removal of the wattles from the landscape. This may be due to lack of locally available alternative options or inability to replace or purchase ecosystem services affected by wattles from other sources or markets like commercial farmers.
- Full Text:
Love at first bite? Pre-release surveys reveal a novel association between a native weevil and the invasive Nymphaea mexicana Zuccarini (Nymphaeaceae) in South Africa
- Reid, Megan K, Hill, Martin P, Coetzee, Julie A
- Authors: Reid, Megan K , Hill, Martin P , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416866 , vital:71392 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a19"
- Description: Classical biological control aims to suppress alien invasive plant populations by introducing host-specific natural enemies from the native range. This relies on the assumption that invasive plant populations in the invaded range benefit from the release of natural enemies. Pre-release surveys in the invaded range are a useful way to determine if enemy release applies to a particular invasive alien plant, and to determine what other factors may contribute to the invasion. Similarly, pre-release surveys gather information that can be used to compare invaded sites before and after the release of biological control agents and may also identify whether natural enemies have been accidentally introduced into the country. Pre-release surveys were conducted in South Africa on the invasive Nymphaea mexicana Zuccarini (Nymphaeaceae) to gather such information about this species, for which a biological control programme is being developed. There was lower diversity and abundance of herbivores in the native range compared to South Africa, suggesting that N. mexicana does experience enemy release at most sites in South Africa. This support for the enemy release hypothesis justifies the investment in biological control for its management. However, a native weevil, Bagous longulus Gyllenhal (Coleoptera: Curculionidae), was found feeding and reproducing on N. mexicana at three sites, resulting in damage to the leaves and suggesting that a novel association has formed between these species. Bagous longulus may have potential to be distributed to sites of N. mexicana where it is not present, though further investigation is necessary to confirm if its host range is suitable for this to be a safe endeavour. With the exception of sites where B. longulus was present, leaf sizes were large and damage was low, and there is no evidence that any natural enemies have been accidentally introduced from the native range. Findings such as these emphasise the importance of conducting thorough surveys during the development of biological control programmes.
- Full Text:
- Authors: Reid, Megan K , Hill, Martin P , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416866 , vital:71392 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a19"
- Description: Classical biological control aims to suppress alien invasive plant populations by introducing host-specific natural enemies from the native range. This relies on the assumption that invasive plant populations in the invaded range benefit from the release of natural enemies. Pre-release surveys in the invaded range are a useful way to determine if enemy release applies to a particular invasive alien plant, and to determine what other factors may contribute to the invasion. Similarly, pre-release surveys gather information that can be used to compare invaded sites before and after the release of biological control agents and may also identify whether natural enemies have been accidentally introduced into the country. Pre-release surveys were conducted in South Africa on the invasive Nymphaea mexicana Zuccarini (Nymphaeaceae) to gather such information about this species, for which a biological control programme is being developed. There was lower diversity and abundance of herbivores in the native range compared to South Africa, suggesting that N. mexicana does experience enemy release at most sites in South Africa. This support for the enemy release hypothesis justifies the investment in biological control for its management. However, a native weevil, Bagous longulus Gyllenhal (Coleoptera: Curculionidae), was found feeding and reproducing on N. mexicana at three sites, resulting in damage to the leaves and suggesting that a novel association has formed between these species. Bagous longulus may have potential to be distributed to sites of N. mexicana where it is not present, though further investigation is necessary to confirm if its host range is suitable for this to be a safe endeavour. With the exception of sites where B. longulus was present, leaf sizes were large and damage was low, and there is no evidence that any natural enemies have been accidentally introduced from the native range. Findings such as these emphasise the importance of conducting thorough surveys during the development of biological control programmes.
- Full Text:
Male peer talk about menstruation: Discursively bolstering hegemonic masculinities among young men in South Africa
- Macleod, Catriona I, Glover, Jonathan M, Makuse, Manase, Kelland, Lindsay, Paphitis, Sharli A
- Authors: Macleod, Catriona I , Glover, Jonathan M , Makuse, Manase , Kelland, Lindsay , Paphitis, Sharli A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441253 , vital:73870 , xlink:href="https://doi.org/10.1080/23293691.2022.2057830"
- Description: In this paper, we show how male peer talk about menstruating women may be used to discursively bolster hegemonic masculinities and denigrate women. Focus group discussions among 37 young isiXhosa-speaking men from two South African schools were facilitated by two young men; statements garnered from a sexuality education class about menstruation conducted in the same schools were used as cues. Data were analyzed using discourse analysis. The interactive talk constructed a bifurcation: “disgusting” menstruating women versus “reasonable” non-menstruating women who abide by idealized feminine behavior and are available sexually. We argue that as the non-menstruating woman cyclically become the other (menstruating woman) in women of particular ages, the trace of disgust inhabits the signifier “woman” for these men. Menstruation also disrupted a core identity strategy of local hegemonic masculinities: virile (hetero)sexuality. Given this, discursive distancing of the self from the very topic of menstruation is necessary. Small moments of resistance to these constructions were quickly closed down, and caring masculinity emerged only in the context of negotiating sex during menstruation. Involving men in menstrual hygiene management programs may provide spaces for resistance to denigrating discourses about menstruation.
- Full Text:
- Authors: Macleod, Catriona I , Glover, Jonathan M , Makuse, Manase , Kelland, Lindsay , Paphitis, Sharli A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441253 , vital:73870 , xlink:href="https://doi.org/10.1080/23293691.2022.2057830"
- Description: In this paper, we show how male peer talk about menstruating women may be used to discursively bolster hegemonic masculinities and denigrate women. Focus group discussions among 37 young isiXhosa-speaking men from two South African schools were facilitated by two young men; statements garnered from a sexuality education class about menstruation conducted in the same schools were used as cues. Data were analyzed using discourse analysis. The interactive talk constructed a bifurcation: “disgusting” menstruating women versus “reasonable” non-menstruating women who abide by idealized feminine behavior and are available sexually. We argue that as the non-menstruating woman cyclically become the other (menstruating woman) in women of particular ages, the trace of disgust inhabits the signifier “woman” for these men. Menstruation also disrupted a core identity strategy of local hegemonic masculinities: virile (hetero)sexuality. Given this, discursive distancing of the self from the very topic of menstruation is necessary. Small moments of resistance to these constructions were quickly closed down, and caring masculinity emerged only in the context of negotiating sex during menstruation. Involving men in menstrual hygiene management programs may provide spaces for resistance to denigrating discourses about menstruation.
- Full Text:
Microbial Community Responses to Alterations in Historical Fire Regimes in Montane Grasslands
- Gokul, Jarishma K, Matcher, Gwynneth, Dames, Joanna F, Nkangala, Kuhle, Gordijn, Paul J, Barker, Nigel P
- Authors: Gokul, Jarishma K , Matcher, Gwynneth , Dames, Joanna F , Nkangala, Kuhle , Gordijn, Paul J , Barker, Nigel P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440366 , vital:73777 , https://doi.org/10.3390/d15070818
- Description: The influence of fire regimes on soil microbial diversity in montane grasslands is a relatively unexplored area of interest. Understanding the belowground diversity is a crucial stepping-stone toward unravelling community dynamics, nutrient sequestration, and overall ecosystem stability. In this study, metabarcoding was used to unravel the impact of fire disturbance regimes on bacterial and arbuscular mycorrhizal fungal community structures in South African montane grasslands that have been subjected to an intermediate (up to five years) term experimental fire-return interval gradient. Bacterial communities in this study exhibited a shift in composition in soils subjected to annual and biennial fires compared to the controls, with carbon and nitrogen identified as significant potential chemical drivers of bacterial communities. Shifts in relative abundances of dominant fungal operational taxonomic units were noted, with Glomeromycota as the dominant arbuscular mycorrhiza observed across the fire-return gradient. A reduction in mycorrhizal root colonisation was also observed in frequently burnt autumnal grassland plots in this study. Furthermore, evidence of significant mutualistic interactions between bacteria and fungi that may act as drivers of the observed community structure were detected. Through this pilot study, we can show that fire regime strongly impacts bacterial and fungal communities in southern African montane grasslands, and that changes to their usually resilient structure are mediated by seasonal burn patterns, chemical drivers, and mutualistic interactions between these two groups.
- Full Text:
- Authors: Gokul, Jarishma K , Matcher, Gwynneth , Dames, Joanna F , Nkangala, Kuhle , Gordijn, Paul J , Barker, Nigel P
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440366 , vital:73777 , https://doi.org/10.3390/d15070818
- Description: The influence of fire regimes on soil microbial diversity in montane grasslands is a relatively unexplored area of interest. Understanding the belowground diversity is a crucial stepping-stone toward unravelling community dynamics, nutrient sequestration, and overall ecosystem stability. In this study, metabarcoding was used to unravel the impact of fire disturbance regimes on bacterial and arbuscular mycorrhizal fungal community structures in South African montane grasslands that have been subjected to an intermediate (up to five years) term experimental fire-return interval gradient. Bacterial communities in this study exhibited a shift in composition in soils subjected to annual and biennial fires compared to the controls, with carbon and nitrogen identified as significant potential chemical drivers of bacterial communities. Shifts in relative abundances of dominant fungal operational taxonomic units were noted, with Glomeromycota as the dominant arbuscular mycorrhiza observed across the fire-return gradient. A reduction in mycorrhizal root colonisation was also observed in frequently burnt autumnal grassland plots in this study. Furthermore, evidence of significant mutualistic interactions between bacteria and fungi that may act as drivers of the observed community structure were detected. Through this pilot study, we can show that fire regime strongly impacts bacterial and fungal communities in southern African montane grasslands, and that changes to their usually resilient structure are mediated by seasonal burn patterns, chemical drivers, and mutualistic interactions between these two groups.
- Full Text:
Mosquito community composition in Central District, Botswana: insights from a malaria endemic to non-endemic gradient
- Buxton, M, Nyamukondiwa, C, Kesamang, M, Wasserman, Ryan J
- Authors: Buxton, M , Nyamukondiwa, C , Kesamang, M , Wasserman, Ryan J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452402 , vital:75126 , http://dx.doi.org/10.17159/2254-8854/2022/a13584
- Description: Spatial distribution of vector mosquitoes plays a critical role in the dynamics of associated diseases' spread across diverse landscapes. In Botswana, six Districts are implicated as malaria endemic zones, one of which is the Central District comprising both malaria endemic and non-endemic sub-districts. Despite being the biggest in the country, mosquito diversity in this District is under-explored, more so in the malaria non-endemic sub-districts. Here, we thus sampled mosquito adults and larvae from the malaria endemic sub-district of Bobirwa and non-endemic sub-districts of Palapye and Serowe, to determine spatial mosquito abundance and diversity in the District.
- Full Text:
- Authors: Buxton, M , Nyamukondiwa, C , Kesamang, M , Wasserman, Ryan J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452402 , vital:75126 , http://dx.doi.org/10.17159/2254-8854/2022/a13584
- Description: Spatial distribution of vector mosquitoes plays a critical role in the dynamics of associated diseases' spread across diverse landscapes. In Botswana, six Districts are implicated as malaria endemic zones, one of which is the Central District comprising both malaria endemic and non-endemic sub-districts. Despite being the biggest in the country, mosquito diversity in this District is under-explored, more so in the malaria non-endemic sub-districts. Here, we thus sampled mosquito adults and larvae from the malaria endemic sub-district of Bobirwa and non-endemic sub-districts of Palapye and Serowe, to determine spatial mosquito abundance and diversity in the District.
- Full Text:
Nagoya Protocol and Africa’s willingness to share biological control agents, are we deterred by barriers instead of using opportunities to work together?
- Ivey, Philip J, Hill, Martin P, Voukeng, Sonia Nadege Kenfack, Weaver, Kim N
- Authors: Ivey, Philip J , Hill, Martin P , Voukeng, Sonia Nadege Kenfack , Weaver, Kim N
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418040 , vital:71503 , xlink:href="https://doi.org/10.1007/s10526-023-10184-8"
- Description: Amongst members of the biological control community there is a range of perceptions regarding the Nagoya Protocol, at best it will hinder access to natural enemies of pests and invasive plants and at worst implementation of the Protocol will prevent access to these resources. In this preliminary study of Africa’s preparedness to implement the Nagoya Protocol and control access to potential biological control agents, we found that several countries have not yet established procedures and policies in this regard. Several factors including lack of awareness, insufficient relevant information and lack of capacity may cause delay in countries implementing access and benefit sharing legislation and processes. The lack of preparedness provides an opportunity for the research community to work with government officials to facilitate future access to natural enemies to act as biological control agents on invasive plants and agricultural pests. Collaboration between researchers, managers and bureaucrats in support of African countries could lead to collective action that develops policies and implements processes to foster exploration of African biodiversity. This collaboration could also foster the sharing of biological control agents that will benefit Africa through integrated pest management in agriculture, protection of human lives and livelihoods, and reduction of the impact of invasive alien species on biodiversity and environmental infrastructure.
- Full Text:
- Authors: Ivey, Philip J , Hill, Martin P , Voukeng, Sonia Nadege Kenfack , Weaver, Kim N
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/418040 , vital:71503 , xlink:href="https://doi.org/10.1007/s10526-023-10184-8"
- Description: Amongst members of the biological control community there is a range of perceptions regarding the Nagoya Protocol, at best it will hinder access to natural enemies of pests and invasive plants and at worst implementation of the Protocol will prevent access to these resources. In this preliminary study of Africa’s preparedness to implement the Nagoya Protocol and control access to potential biological control agents, we found that several countries have not yet established procedures and policies in this regard. Several factors including lack of awareness, insufficient relevant information and lack of capacity may cause delay in countries implementing access and benefit sharing legislation and processes. The lack of preparedness provides an opportunity for the research community to work with government officials to facilitate future access to natural enemies to act as biological control agents on invasive plants and agricultural pests. Collaboration between researchers, managers and bureaucrats in support of African countries could lead to collective action that develops policies and implements processes to foster exploration of African biodiversity. This collaboration could also foster the sharing of biological control agents that will benefit Africa through integrated pest management in agriculture, protection of human lives and livelihoods, and reduction of the impact of invasive alien species on biodiversity and environmental infrastructure.
- Full Text:
Nature-Connectedness and Well-Being Experienced During Best and Worst Times of Life: A Case for Safeguarding Biocultural Diversity
- Møller, Valerie, Cocks, Michelle L, Vetter, Susanne
- Authors: Møller, Valerie , Cocks, Michelle L , Vetter, Susanne
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426516 , vital:72359 , xlink:href="https://doi.org/10.1007/s11205-023-03063-3"
- Description: South Africa boasts some of the richest diversity of fauna and flora in the world; it also claims to be a world in one country given its cultural diversity. In a time of climate change, rapid population growth and urbanisation, the country’s natural resources as well as its cultural diversity are under threat. We report a multi-dimensional survey conducted among Xhosa-speaking people in the Eastern Cape Province of South Africa, that collected detailed information on indigenous knowledge of nature and its impact on cultural practices and well-being. Survey respondents included both rural and urban dwellers, a majority of whom professed to be Christians who also held traditional religious beliefs and acknowledged the ancestors. Survey respondents described their Best and Worst periods of life in line with Bernheim’s Anamnestic Comparative Self-Assessment, and indicated whether going into nature had contributed to their Best life experience and helped them to cope during their Worst one. Being in nature typically contributed to well-being across many of the Best social domains of life, such as celebrations with family, personal achievements and milestones in life, including traditional rites of passage to adulthood. Deaths in the family represented by far the most common Worst experience in life when going into nature often provided comfort and solace. Findings suggest that experience of the multiple benefits of being in nature may be universal across cultures and that many traditional Xhosa religious beliefs and cultural practices go hand in hand with access and exposure to nature that enhances well-being.
- Full Text:
- Authors: Møller, Valerie , Cocks, Michelle L , Vetter, Susanne
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426516 , vital:72359 , xlink:href="https://doi.org/10.1007/s11205-023-03063-3"
- Description: South Africa boasts some of the richest diversity of fauna and flora in the world; it also claims to be a world in one country given its cultural diversity. In a time of climate change, rapid population growth and urbanisation, the country’s natural resources as well as its cultural diversity are under threat. We report a multi-dimensional survey conducted among Xhosa-speaking people in the Eastern Cape Province of South Africa, that collected detailed information on indigenous knowledge of nature and its impact on cultural practices and well-being. Survey respondents included both rural and urban dwellers, a majority of whom professed to be Christians who also held traditional religious beliefs and acknowledged the ancestors. Survey respondents described their Best and Worst periods of life in line with Bernheim’s Anamnestic Comparative Self-Assessment, and indicated whether going into nature had contributed to their Best life experience and helped them to cope during their Worst one. Being in nature typically contributed to well-being across many of the Best social domains of life, such as celebrations with family, personal achievements and milestones in life, including traditional rites of passage to adulthood. Deaths in the family represented by far the most common Worst experience in life when going into nature often provided comfort and solace. Findings suggest that experience of the multiple benefits of being in nature may be universal across cultures and that many traditional Xhosa religious beliefs and cultural practices go hand in hand with access and exposure to nature that enhances well-being.
- Full Text:
Oxpecker host-selection in the Salambala conservancy, northeastern Namibia
- Lukubwe, Michael S, Craig, Adrian J F K, Manyangadze, Tawanda
- Authors: Lukubwe, Michael S , Craig, Adrian J F K , Manyangadze, Tawanda
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449934 , vital:74866 , https://doi.org/10.3957/056.053.0166
- Description: By studying the host-selection patterns of oxpecker species, researchers can gain valuable insights into their ecological roles and interactions with different host species. This information is crucial for developing effective conservation strategies that prioritise the protection of oxpeckers and their host populations. The study conducted field observations and recorded data on the number of oxpeckers and their respective host species. Additionally, this study investigated the relationship between host species and host parameters (body mass and hair length) in the Salambala conservancy in northeastern Namibia. Selection and density indices were used to calculate the number of host animals supporting one oxpecker as well as the oxpecker density on a host's body surface. Pentad-based counts of oxpeckers and ungulates were conducted.
- Full Text:
- Authors: Lukubwe, Michael S , Craig, Adrian J F K , Manyangadze, Tawanda
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449934 , vital:74866 , https://doi.org/10.3957/056.053.0166
- Description: By studying the host-selection patterns of oxpecker species, researchers can gain valuable insights into their ecological roles and interactions with different host species. This information is crucial for developing effective conservation strategies that prioritise the protection of oxpeckers and their host populations. The study conducted field observations and recorded data on the number of oxpeckers and their respective host species. Additionally, this study investigated the relationship between host species and host parameters (body mass and hair length) in the Salambala conservancy in northeastern Namibia. Selection and density indices were used to calculate the number of host animals supporting one oxpecker as well as the oxpecker density on a host's body surface. Pentad-based counts of oxpeckers and ungulates were conducted.
- Full Text:
Performance and field host range of the life stages of Cornops aquaticum, a biological control agent of water hyacinth
- Franceschini, M Celeste, Hill, Martin P, Fuentes-Rodríguez, Daniela, Gervazoni, Paula B, Sabater, Lara M, Coetzee, Julie A
- Authors: Franceschini, M Celeste , Hill, Martin P , Fuentes-Rodríguez, Daniela , Gervazoni, Paula B , Sabater, Lara M , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424814 , vital:72186 , xlink:href="https://doi.org/10.1111/eea.13354"
- Description: Host specificity determination of weed biocontrol agents has historically relied on evidence generated through quarantine trials in the region of introduction. These trials could give ‘false positive’ results due to a maximum type I error probability, and where possible, more research under field conditions should be conducted in the region of origin. The oligophagous, semiaquatic grasshopper, Cornops aquaticum Bruner (Orthoptera: Acrididae, Tetrataeniini), was released in South Africa for the biological control of Pontederia crassipes Pellegrini and Horn (Pontederiaceae). The aim of this study was to assess how the performance and field host range of C. aquaticum varies according to its stages of development, and how this contributes to the understanding of the relationship between the fundamental (laboratory-based) and the ecological (field-based) host range of this grasshopper, and its implications for water hyacinth biocontrol. We conducted post-release laboratory no-choice trials, confining early instars (instars 1 and 2), later instars (instars 3–6), and adult females and males in mesh cages, to determine insect performance on wetland plants growing in sympatry with P. crassipes. Also, gut analysis from field-collected C. aquaticum was done to determine the ecological host range of this insect, identifying epidermal tissue of consumed plants. In no-choice trials, survival rates of the later instars and adult C. aquaticum were similar on Pistia stratiotes L. (Araceae), Oxycaryum cubense (Poepp. and Kunth) Lye (Cyperaceae), and P. crassipes. However, under field conditions, P. crassipes and the congeneric Pontederia azurea Sw. were the only plant contents in the guts of early instars and the most abundant species in later instars and adults. The results support the hypothesis that C. aquaticum is an oligophagous insect on the genus Pontederia, and that different life stages should be considered when conducting host-specificity trials in externally feeding mobile herbivore species. Diet composition of field-collected insects thus could help detect false positives in laboratory trials, being an additional and realistic approach in understanding and predicting the selection processes of the insect in the new environment. Retrospective analysis of potential agents that were rejected due to lack of host-specificity, using the methods from this study, could add a suite of additional agents to programs where invasive weeds remain unmanaged.
- Full Text:
- Authors: Franceschini, M Celeste , Hill, Martin P , Fuentes-Rodríguez, Daniela , Gervazoni, Paula B , Sabater, Lara M , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/424814 , vital:72186 , xlink:href="https://doi.org/10.1111/eea.13354"
- Description: Host specificity determination of weed biocontrol agents has historically relied on evidence generated through quarantine trials in the region of introduction. These trials could give ‘false positive’ results due to a maximum type I error probability, and where possible, more research under field conditions should be conducted in the region of origin. The oligophagous, semiaquatic grasshopper, Cornops aquaticum Bruner (Orthoptera: Acrididae, Tetrataeniini), was released in South Africa for the biological control of Pontederia crassipes Pellegrini and Horn (Pontederiaceae). The aim of this study was to assess how the performance and field host range of C. aquaticum varies according to its stages of development, and how this contributes to the understanding of the relationship between the fundamental (laboratory-based) and the ecological (field-based) host range of this grasshopper, and its implications for water hyacinth biocontrol. We conducted post-release laboratory no-choice trials, confining early instars (instars 1 and 2), later instars (instars 3–6), and adult females and males in mesh cages, to determine insect performance on wetland plants growing in sympatry with P. crassipes. Also, gut analysis from field-collected C. aquaticum was done to determine the ecological host range of this insect, identifying epidermal tissue of consumed plants. In no-choice trials, survival rates of the later instars and adult C. aquaticum were similar on Pistia stratiotes L. (Araceae), Oxycaryum cubense (Poepp. and Kunth) Lye (Cyperaceae), and P. crassipes. However, under field conditions, P. crassipes and the congeneric Pontederia azurea Sw. were the only plant contents in the guts of early instars and the most abundant species in later instars and adults. The results support the hypothesis that C. aquaticum is an oligophagous insect on the genus Pontederia, and that different life stages should be considered when conducting host-specificity trials in externally feeding mobile herbivore species. Diet composition of field-collected insects thus could help detect false positives in laboratory trials, being an additional and realistic approach in understanding and predicting the selection processes of the insect in the new environment. Retrospective analysis of potential agents that were rejected due to lack of host-specificity, using the methods from this study, could add a suite of additional agents to programs where invasive weeds remain unmanaged.
- Full Text:
Persistent effects of historical sea levels on the population structure of a temporary wetland copepod
- Emami-Khoyi, Arsalan, Jooste, Candice M, Wasserman, Ryan J, Dalu, Tatenda, Raath-Krüger, Morgan J, Jansen van Vuuren, Bettine, Teske, Peter R
- Authors: Emami-Khoyi, Arsalan , Jooste, Candice M , Wasserman, Ryan J , Dalu, Tatenda , Raath-Krüger, Morgan J , Jansen van Vuuren, Bettine , Teske, Peter R
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445115 , vital:74348 , https://doi.org/10.1111/fwb.14139
- Description: Temporary wetland ecosystems are common in arid and semi‐arid envi-ronments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geograph-ically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well‐connected population or comprises different regional genetic groups, some of which may be rare or endangered.
- Full Text:
- Authors: Emami-Khoyi, Arsalan , Jooste, Candice M , Wasserman, Ryan J , Dalu, Tatenda , Raath-Krüger, Morgan J , Jansen van Vuuren, Bettine , Teske, Peter R
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445115 , vital:74348 , https://doi.org/10.1111/fwb.14139
- Description: Temporary wetland ecosystems are common in arid and semi‐arid envi-ronments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geograph-ically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well‐connected population or comprises different regional genetic groups, some of which may be rare or endangered.
- Full Text:
Photoantimicrobial activity of Schiff-base morpholino phthalocyanines against drug resistant micro-organisms in their planktonic and biofilm forms
- Sindelo, Azole, Sen, Pinar, Nyokong, Tebello
- Authors: Sindelo, Azole , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360437 , vital:65088 , xlink:href="https://doi.org/10.1016/j.pdpdt.2023.103519"
- Description: Antimicrobial photodynamic inactivation (aPDI) is a treatment for the eradication of drug-resistant micro-organisms. One of the advantages of this technique, is that there is minimal possibility of microbial resistance. Hence, herein, the preparation and characterization of novel neutral and cationic morpholine containing Schiff base phthalocyanines are reported. The cationic complexes gave moderate singlet oxygen quantum yields (ΦΔ) of ∼0.2 in aqueous media. Conversely, the neutral complexes generated very low ΦΔ values making them very poor candidates for antimicrobial studies. The cationic phthalocyanines showed excellent photodynamic activity against planktonic cells of all micro-organisms (Candida albicans, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella enterica subspecies enterica serovar Choleraesuis, vancomycin-resistant Enterococcus faecium, and methicillin-resistant Staphylococcus aureus). The efficiency of aPDI was shown to be both concentration and light-dose-dependent. Mono biofilms were susceptible when treated with 200 µM of cationic Pcs at 108 J/cm2. However, ∼10% of the mixed biofilm survived after treatment.
- Full Text:
- Authors: Sindelo, Azole , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360437 , vital:65088 , xlink:href="https://doi.org/10.1016/j.pdpdt.2023.103519"
- Description: Antimicrobial photodynamic inactivation (aPDI) is a treatment for the eradication of drug-resistant micro-organisms. One of the advantages of this technique, is that there is minimal possibility of microbial resistance. Hence, herein, the preparation and characterization of novel neutral and cationic morpholine containing Schiff base phthalocyanines are reported. The cationic complexes gave moderate singlet oxygen quantum yields (ΦΔ) of ∼0.2 in aqueous media. Conversely, the neutral complexes generated very low ΦΔ values making them very poor candidates for antimicrobial studies. The cationic phthalocyanines showed excellent photodynamic activity against planktonic cells of all micro-organisms (Candida albicans, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella enterica subspecies enterica serovar Choleraesuis, vancomycin-resistant Enterococcus faecium, and methicillin-resistant Staphylococcus aureus). The efficiency of aPDI was shown to be both concentration and light-dose-dependent. Mono biofilms were susceptible when treated with 200 µM of cationic Pcs at 108 J/cm2. However, ∼10% of the mixed biofilm survived after treatment.
- Full Text:
Photodynamic inactivation of methicillin-resistant Staphylococcus aureus using pyrrolidinium containing Schiff base phthalocyanines
- Sindelo, Azole, Sen, Pinar, Nyokong, Tebello
- Authors: Sindelo, Azole , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360449 , vital:65089 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114535"
- Description: New tetra-substituted zinc and indium Schiff base phthalocyanines (ZnPc and InPc, respectively) are synthesized and characterized herein. The ethyl pyrrolidine (ZnPc-2, InPc-2) and propyl pyrrolidine (ZnPc-3, InPc-3) substituted Schiff base Pcs were reacted with methyl iodide to form their cationic derivatives (ZnPc-2Q, InPc-2Q, ZnPc-3Q, and InPc-3Q, respectively). The photophysical and photochemical properties of the Pcs were studied. The cationic Pcs generated higher singlet oxygen quantum yield in aqueous media than the neutral Pcs. The photoinactivation of Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) strains was evaluated. 5 µM ZnPc-3Q and InPc-3Q inactivated 100 % of the MSSA and MRSA while 5 µM ZnPc-2Q and InPc-2Q eradicated 100 % for MSSA and 97.2 % and 98.7 % (respectively) of the MRSA. The photodynamic antimicrobial chemotherapy studies depended on singlet oxygen ability, the charges, and the extension of the alkyl groups.
- Full Text:
- Authors: Sindelo, Azole , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360449 , vital:65089 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114535"
- Description: New tetra-substituted zinc and indium Schiff base phthalocyanines (ZnPc and InPc, respectively) are synthesized and characterized herein. The ethyl pyrrolidine (ZnPc-2, InPc-2) and propyl pyrrolidine (ZnPc-3, InPc-3) substituted Schiff base Pcs were reacted with methyl iodide to form their cationic derivatives (ZnPc-2Q, InPc-2Q, ZnPc-3Q, and InPc-3Q, respectively). The photophysical and photochemical properties of the Pcs were studied. The cationic Pcs generated higher singlet oxygen quantum yield in aqueous media than the neutral Pcs. The photoinactivation of Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) strains was evaluated. 5 µM ZnPc-3Q and InPc-3Q inactivated 100 % of the MSSA and MRSA while 5 µM ZnPc-2Q and InPc-2Q eradicated 100 % for MSSA and 97.2 % and 98.7 % (respectively) of the MRSA. The photodynamic antimicrobial chemotherapy studies depended on singlet oxygen ability, the charges, and the extension of the alkyl groups.
- Full Text:
Rationalising the retro-Diels-Alder fragmentation pattern of viscutins using electrospray interface-tandem mass spectrometry coupled to theoretical modelling
- Moyo, Babra, Novokoza, Yolanda, Tavengwa, Nikita T, Kuhnert, Nikolai, Lobb, Kevin A, Madala, Ntakadzeni E
- Authors: Moyo, Babra , Novokoza, Yolanda , Tavengwa, Nikita T , Kuhnert, Nikolai , Lobb, Kevin A , Madala, Ntakadzeni E
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452786 , vital:75170 , xlink:href="https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9592"
- Description: Although mass spectrometry (MS) is a powerful tool in structural elucidation of unknown flavonoids based on their unique fragmentation patterns, proposing the correct fragmentation mechanism is still a challenge from tandem mass spectrometry data only. In recent years, computational tools such as molecular networking and MS2LDA have played a major role in the identification of structurally related compounds through an in-depth survey of their fragmentation patterns.
- Full Text:
- Authors: Moyo, Babra , Novokoza, Yolanda , Tavengwa, Nikita T , Kuhnert, Nikolai , Lobb, Kevin A , Madala, Ntakadzeni E
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452786 , vital:75170 , xlink:href="https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.9592"
- Description: Although mass spectrometry (MS) is a powerful tool in structural elucidation of unknown flavonoids based on their unique fragmentation patterns, proposing the correct fragmentation mechanism is still a challenge from tandem mass spectrometry data only. In recent years, computational tools such as molecular networking and MS2LDA have played a major role in the identification of structurally related compounds through an in-depth survey of their fragmentation patterns.
- Full Text:
Sample size assessments for thermal physiology studies: An R package and R Shiny application
- van Steenderen, Clarke J M, Sutton, Guy F, Owen, Candice A, Martin, Grant D, Coetzee, Julie A
- Authors: van Steenderen, Clarke J M , Sutton, Guy F , Owen, Candice A , Martin, Grant D , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444455 , vital:74242 , https://doi.org/10.1111/phen.12416
- Description: Required sample sizes for a study need to be carefully assessed to account for logistics, cost, ethics and statistical rigour. For example, many studies have shown that methodological variations can impact the critical thermal limits (CTLs) recorded for a species, although studies on the impact of sample size on these measures are lacking. Here, we present ThermalSampleR; an R CRAN package and Shiny application that can assist researchers in determining when adequate sample sizes have been reached for their data. The method is particularly useful because it is not taxon specific. The Shiny application offers a user‐friendly interface equivalent to the package for users not familiar with R programming. ThermalSampleR is accompanied by an in‐built example dataset, which we use to guide the user through the workflow with a fully worked tutorial.
- Full Text:
- Authors: van Steenderen, Clarke J M , Sutton, Guy F , Owen, Candice A , Martin, Grant D , Coetzee, Julie A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444455 , vital:74242 , https://doi.org/10.1111/phen.12416
- Description: Required sample sizes for a study need to be carefully assessed to account for logistics, cost, ethics and statistical rigour. For example, many studies have shown that methodological variations can impact the critical thermal limits (CTLs) recorded for a species, although studies on the impact of sample size on these measures are lacking. Here, we present ThermalSampleR; an R CRAN package and Shiny application that can assist researchers in determining when adequate sample sizes have been reached for their data. The method is particularly useful because it is not taxon specific. The Shiny application offers a user‐friendly interface equivalent to the package for users not familiar with R programming. ThermalSampleR is accompanied by an in‐built example dataset, which we use to guide the user through the workflow with a fully worked tutorial.
- Full Text: