The Electrocatalytic Detection of Nitrite Using Manganese Schiff Base Phthalocyanine Complexes
- Ndebele, Nobuhle, Nyokong, Tebello
- Authors: Ndebele, Nobuhle , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295856 , vital:57385 , xlink:href="https://doi.org/10.1007/s12678-022-00752-4"
- Description: This work investigates the use of manganese phthalocyanines (MnPcs) in the electrochemical detection of nitrite. These are two Schiff base derivatives: tetrakis 4-(4-thio-thiophene-2-ylmethanamino) phthalocyaninato Mn(III)Cl (2) and tetrakis 4-(3-(pyrrolidine-1-yl)propan-1-amino)phthalocyaninato Mn(III)Cl (3) and one aldehyde: tetrakis(4-formylphenoxy)phthalocyaninato Mn(III)Cl (1). The MnPc complexes were adsorbed onto the glassy carbon electrode surface using the drop-dry method and used as electrocatalysts to detect nitrite. Nitrite oxidation peak potentials obtained using cyclic voltammetry ranged between 0.70 and 0.84 V. Detection limits as low as 0.16 µM and sensitivity values as high as 276 µMmM−1 were obtained through the use of chronoamperometry. The Schiff base MnPcs 2 and 3 exhibited better nitrite detection properties (in terms of limit of detection and sensitivity) than their aldehyde precursor (1).
- Full Text:
- Date Issued: 2022
- Authors: Ndebele, Nobuhle , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295856 , vital:57385 , xlink:href="https://doi.org/10.1007/s12678-022-00752-4"
- Description: This work investigates the use of manganese phthalocyanines (MnPcs) in the electrochemical detection of nitrite. These are two Schiff base derivatives: tetrakis 4-(4-thio-thiophene-2-ylmethanamino) phthalocyaninato Mn(III)Cl (2) and tetrakis 4-(3-(pyrrolidine-1-yl)propan-1-amino)phthalocyaninato Mn(III)Cl (3) and one aldehyde: tetrakis(4-formylphenoxy)phthalocyaninato Mn(III)Cl (1). The MnPc complexes were adsorbed onto the glassy carbon electrode surface using the drop-dry method and used as electrocatalysts to detect nitrite. Nitrite oxidation peak potentials obtained using cyclic voltammetry ranged between 0.70 and 0.84 V. Detection limits as low as 0.16 µM and sensitivity values as high as 276 µMmM−1 were obtained through the use of chronoamperometry. The Schiff base MnPcs 2 and 3 exhibited better nitrite detection properties (in terms of limit of detection and sensitivity) than their aldehyde precursor (1).
- Full Text:
- Date Issued: 2022
The photocatalytic properties of zinc phthalocyanines supported on hematite nanofibers for use against methyl orange and Staphylococcus aureus
- Mapukata, Sivuyisiwe, Britton, Jonathan, Nwahara, Nnamdi, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Britton, Jonathan , Nwahara, Nnamdi , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230184 , vital:49751 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113637"
- Description: Heterogeneous photocatalysis is a promising approach for environmental remediation from contaminants including microorganisms and organic pollutants. In this work, hematite nanofibers are fabricated and modified with a novel monosubstituted Pc (4) as well as an asymmetrical tetrasubstituted Pc (5) with the aim of creating hybrid photocatalysts. The photocatalytic activities of the unmodified and phthalocyanine modified hematite nanofibers were compared based on their efficiencies in the photoinactivation of S. aureus and photooxidation of methyl orange. For both applications, the hybrid nanofibers were found to be more efficient photocatalysts than the unmodified hematite nanofibers. Comparison of the modified nanofibers (4-Fe2O3 and 5-Fe2O3) showed that they have comparable antibacterial activity while the 5-Fe2O3 nanofibers are the best for the photooxidation of methyl orange. The singlet oxygen generation efficiency, high activity, versatility, regenerability and thus reusability of the fabricated hybrid nanofibers makes them ideal candidates for real life water treatment studies.
- Full Text:
- Date Issued: 2022
- Authors: Mapukata, Sivuyisiwe , Britton, Jonathan , Nwahara, Nnamdi , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230184 , vital:49751 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113637"
- Description: Heterogeneous photocatalysis is a promising approach for environmental remediation from contaminants including microorganisms and organic pollutants. In this work, hematite nanofibers are fabricated and modified with a novel monosubstituted Pc (4) as well as an asymmetrical tetrasubstituted Pc (5) with the aim of creating hybrid photocatalysts. The photocatalytic activities of the unmodified and phthalocyanine modified hematite nanofibers were compared based on their efficiencies in the photoinactivation of S. aureus and photooxidation of methyl orange. For both applications, the hybrid nanofibers were found to be more efficient photocatalysts than the unmodified hematite nanofibers. Comparison of the modified nanofibers (4-Fe2O3 and 5-Fe2O3) showed that they have comparable antibacterial activity while the 5-Fe2O3 nanofibers are the best for the photooxidation of methyl orange. The singlet oxygen generation efficiency, high activity, versatility, regenerability and thus reusability of the fabricated hybrid nanofibers makes them ideal candidates for real life water treatment studies.
- Full Text:
- Date Issued: 2022
5-Fu inclusion complex capped gold nanoparticles for breast cancer therapy
- Lakkakula, Jaya R, Krause, Rui W M, Divakaran, Deepika, Barage, Sagar, Srivastava, Rohit
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
A critical appraisal of the recruitment and selection process of the Public Protector in South Africa
- Bazana, Sandiso, Reddy, Tayra
- Authors: Bazana, Sandiso , Reddy, Tayra
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453707 , vital:75279 , xlink:href=" https://journals.co.za/doi/full/10.4102/sajhrm.v19i0.1207"
- Description: Orientation: The process of recruitment and selection the Public Protector (PP) needs to ensure that the most ‘fit and proper’ candidate is appointed. The process needs critical scrutiny for such a fit and proper candidate to be selected. Research motivation: South Africa’s superior courts, including the Constitutional court have recently (in 2019) labelled the current Public Protector; dishonest and Incompetent in carrying out the duties of the PP office. Research purpose: This article critically appraises the recent process that culminated in the appointment of Ms Busisiwe Mkhwebane as the fourth Public Protector in the democratic South Africa.
- Full Text:
- Date Issued: 2021
- Authors: Bazana, Sandiso , Reddy, Tayra
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453707 , vital:75279 , xlink:href=" https://journals.co.za/doi/full/10.4102/sajhrm.v19i0.1207"
- Description: Orientation: The process of recruitment and selection the Public Protector (PP) needs to ensure that the most ‘fit and proper’ candidate is appointed. The process needs critical scrutiny for such a fit and proper candidate to be selected. Research motivation: South Africa’s superior courts, including the Constitutional court have recently (in 2019) labelled the current Public Protector; dishonest and Incompetent in carrying out the duties of the PP office. Research purpose: This article critically appraises the recent process that culminated in the appointment of Ms Busisiwe Mkhwebane as the fourth Public Protector in the democratic South Africa.
- Full Text:
- Date Issued: 2021
Arylquinolinecarboxamides: Synthesis, in vitro and in silico studies against Mycobacterium tuberculosis
- Bokosi, Fostino R B, Beteck, Richard M, Jordaan, Audrey, Seldon, Ronnett, Warner, Digby F, Tshiwawa, Tendamudzimu, Lobb, Kevin A, Khanye, Setshaba D
- Authors: Bokosi, Fostino R B , Beteck, Richard M , Jordaan, Audrey , Seldon, Ronnett , Warner, Digby F , Tshiwawa, Tendamudzimu , Lobb, Kevin A , Khanye, Setshaba D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451064 , vital:75015 , xlink:href="https://doi.org/10.1002/jhet.4340"
- Description: A series of fourteen 6-substituted-2-(methoxyquinolin-3-yl) methyl)-N-(pyridin-3-ylmethyl) benzamides was prepared from commercially available anilines infive simple and convenient synthetic steps. The structures of all new productswere confirmed by routine spectroscopic methods: IR,1Hand13 CNMR,andHRMS (electrospray ionization). The resulting arylquinolinecarboxamides weresubjected to biological screening assay forin vitroinhibitory activity againstMyco-bacterium tuberculosis (Mtb) H37Rv strain. Several compounds exhibited modestantitubercular activity with compounds8–11,15and19exhibiting MIC90valuesin the range of 32–85μM. The antitubercular data suggested that inhibition ofMtbcan be imparted by the introduction of a non-polar substituent on C-6 of thequinoline scaffold. Further, to understandthepossiblemodeofactionoftheseries, the reported compounds and bedaquiline were subjected toin silicodock-ing studies againstMtbATPase to determine their potential to interfere with themycobacterial adenosine triphosphate (ATP) synthase. The results showed thatthese compounds have the potential toserve as antimycobacterial agents.In silicoADME pharmacokinetic prediction results showed the ability of thesearylquinolinecarcboxamides to be absorbed, distributed, metabolized andexcreted efficiently.
- Full Text:
- Date Issued: 2021
- Authors: Bokosi, Fostino R B , Beteck, Richard M , Jordaan, Audrey , Seldon, Ronnett , Warner, Digby F , Tshiwawa, Tendamudzimu , Lobb, Kevin A , Khanye, Setshaba D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451064 , vital:75015 , xlink:href="https://doi.org/10.1002/jhet.4340"
- Description: A series of fourteen 6-substituted-2-(methoxyquinolin-3-yl) methyl)-N-(pyridin-3-ylmethyl) benzamides was prepared from commercially available anilines infive simple and convenient synthetic steps. The structures of all new productswere confirmed by routine spectroscopic methods: IR,1Hand13 CNMR,andHRMS (electrospray ionization). The resulting arylquinolinecarboxamides weresubjected to biological screening assay forin vitroinhibitory activity againstMyco-bacterium tuberculosis (Mtb) H37Rv strain. Several compounds exhibited modestantitubercular activity with compounds8–11,15and19exhibiting MIC90valuesin the range of 32–85μM. The antitubercular data suggested that inhibition ofMtbcan be imparted by the introduction of a non-polar substituent on C-6 of thequinoline scaffold. Further, to understandthepossiblemodeofactionoftheseries, the reported compounds and bedaquiline were subjected toin silicodock-ing studies againstMtbATPase to determine their potential to interfere with themycobacterial adenosine triphosphate (ATP) synthase. The results showed thatthese compounds have the potential toserve as antimycobacterial agents.In silicoADME pharmacokinetic prediction results showed the ability of thesearylquinolinecarcboxamides to be absorbed, distributed, metabolized andexcreted efficiently.
- Full Text:
- Date Issued: 2021
Covid-19 and the restrictive measures: The national security conundrum for Zimbabwe
- Mugari, Ishmael, Obioha, Emeka E.
- Authors: Mugari, Ishmael , Obioha, Emeka E.
- Date: 2021
- Subjects: COVID-19 (Disease) National security Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6926 , vital:52571 , xlink:href="https://10.1080/10246029.2021.1972015"
- Description: The emergence of the COVID-19 pandemic at the onset of the year 2020 brought unprecedented suffering to humanity. Economic activities in virtually all nations across the globe were brought to a shuddering halt, with the third world suffering the worst effects on the economic front. The health security of nations across the globe was shaken, as nations came to terms with the surging health needs for the infected citizens. In order to grapple with the pandemic, nations took drastic measures, chief among them being the implementation of lockdowns, coupled with harsh restrictions. These measures, however, came at a cost. This paper explores the impacts of the restrictive measures that were implemented by the Zimbabwean government to combat COVID-19 pandemic. The paper interrogates these measures in the context of the national security discourse. In the analysis, the paper also makes reference to South Africa- a more developed nation and Zimbabwe’s neighbour. Keywords: COVID-19 , national security, health security, lockdown
- Full Text:
- Date Issued: 2021
- Authors: Mugari, Ishmael , Obioha, Emeka E.
- Date: 2021
- Subjects: COVID-19 (Disease) National security Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6926 , vital:52571 , xlink:href="https://10.1080/10246029.2021.1972015"
- Description: The emergence of the COVID-19 pandemic at the onset of the year 2020 brought unprecedented suffering to humanity. Economic activities in virtually all nations across the globe were brought to a shuddering halt, with the third world suffering the worst effects on the economic front. The health security of nations across the globe was shaken, as nations came to terms with the surging health needs for the infected citizens. In order to grapple with the pandemic, nations took drastic measures, chief among them being the implementation of lockdowns, coupled with harsh restrictions. These measures, however, came at a cost. This paper explores the impacts of the restrictive measures that were implemented by the Zimbabwean government to combat COVID-19 pandemic. The paper interrogates these measures in the context of the national security discourse. In the analysis, the paper also makes reference to South Africa- a more developed nation and Zimbabwe’s neighbour. Keywords: COVID-19 , national security, health security, lockdown
- Full Text:
- Date Issued: 2021
Creating the Ideal Push-Pull System for Electrocatalysis A Comparative Study on Symmetrical and Asymmetrical Cardanol-based Cobalt Phthalocyanines
- Nkhahle, Reitumetse, Nyokong, Tebello
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:44452 , xlink:href="https://doi.org/10.1002/elan.202060019"
- Description: A symmetrical cardanol-based cobalt phthalocyanine (Pc) along with its asymmetrical acid-based derivatives were synthesized and applied in the electrocatalysis of hydrazine. Despite the inhibition of electron movement by the bulky cardanol-based substituent throughout the series of molecules, an ideal combination of substituents was established in GCE-3 (2,9,16-tris(3- pentadecylphenoxy)-23-mono propionic acid phthalocyanato cobalt (II)) where a limit of detection (LoD) value of 5.10 μM (signal to noise ratio=5) was recorded for the detection of hydrazine. The results obtained serve as an illustration that the combination of electron-donating and electron-withdrawing substituents has a significant influence on the complete functioning of the phthalocyanine molecule(s) being investigated.
- Full Text:
- Date Issued: 2021
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:44452 , xlink:href="https://doi.org/10.1002/elan.202060019"
- Description: A symmetrical cardanol-based cobalt phthalocyanine (Pc) along with its asymmetrical acid-based derivatives were synthesized and applied in the electrocatalysis of hydrazine. Despite the inhibition of electron movement by the bulky cardanol-based substituent throughout the series of molecules, an ideal combination of substituents was established in GCE-3 (2,9,16-tris(3- pentadecylphenoxy)-23-mono propionic acid phthalocyanato cobalt (II)) where a limit of detection (LoD) value of 5.10 μM (signal to noise ratio=5) was recorded for the detection of hydrazine. The results obtained serve as an illustration that the combination of electron-donating and electron-withdrawing substituents has a significant influence on the complete functioning of the phthalocyanine molecule(s) being investigated.
- Full Text:
- Date Issued: 2021
Effect of ultrasonic frequency and power on the sonodynamic therapy activity of cationic Zn (II) phthalocyanines
- Nene, Lindokuhle C, Sindelo, Azole, Britton, Jonathan, Nyokong, Tebello
- Authors: Nene, Lindokuhle C , Sindelo, Azole , Britton, Jonathan , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185737 , vital:44419 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111397"
- Description: We report on the sonodynamic activity of cationic phthalocyanines (Pcs) and the effect of the variation of two parameters: ultrasound frequency and power (Par I (1 MHz, 1 W cm−2), Par II (1 MHz, 2 W cm−2), Par III (3 MHz, 1 W cm−2) and Par IV (3 MHz, 2 W cm−2)) on the efficiency of their reactive oxygen species generation and cancer eradication in vitro thereof. Where Par stands for the various combinations of these parameters. Four Pcs were investigated with substituents bearing diethylamine, ortho- and para-pyridine and morpholine groups. Overall, the para-pyridine and morpholine Pcs showed substantial sono-activity in the various ultrasound parameters with Par I and IV generally showing better singlet oxygen and hydroxyl radicals generation confirmed by electron paramagnetic resonance spectroscopy. In some cases, very high hydroxyl radicals' generation was observed at Par II. Furthermore, the fragmentation of the Pcs after Par II treatments was confirmed using UV–vis and magnetic circular dichroism spectroscopy. The reactive species generation efficacy decreased at Par III for all samples. Ultrasound assisted cytotoxicity of the Pcs was confirmed in vitro using the human (Michigan Cancer Foundation-7) breast cancer cell line.
- Full Text:
- Date Issued: 2021
- Authors: Nene, Lindokuhle C , Sindelo, Azole , Britton, Jonathan , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185737 , vital:44419 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111397"
- Description: We report on the sonodynamic activity of cationic phthalocyanines (Pcs) and the effect of the variation of two parameters: ultrasound frequency and power (Par I (1 MHz, 1 W cm−2), Par II (1 MHz, 2 W cm−2), Par III (3 MHz, 1 W cm−2) and Par IV (3 MHz, 2 W cm−2)) on the efficiency of their reactive oxygen species generation and cancer eradication in vitro thereof. Where Par stands for the various combinations of these parameters. Four Pcs were investigated with substituents bearing diethylamine, ortho- and para-pyridine and morpholine groups. Overall, the para-pyridine and morpholine Pcs showed substantial sono-activity in the various ultrasound parameters with Par I and IV generally showing better singlet oxygen and hydroxyl radicals generation confirmed by electron paramagnetic resonance spectroscopy. In some cases, very high hydroxyl radicals' generation was observed at Par II. Furthermore, the fragmentation of the Pcs after Par II treatments was confirmed using UV–vis and magnetic circular dichroism spectroscopy. The reactive species generation efficacy decreased at Par III for all samples. Ultrasound assisted cytotoxicity of the Pcs was confirmed in vitro using the human (Michigan Cancer Foundation-7) breast cancer cell line.
- Full Text:
- Date Issued: 2021
Field-based ecological studies to assess prospective biological control agents for invasive alien plants: An example from giant rat's tail grass
- Sutton, Guy F, Canavan, Kim N, Day, Michael M, Paterson, Iain D
- Authors: Sutton, Guy F , Canavan, Kim N , Day, Michael M , Paterson, Iain D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423756 , vital:72091 , xlink:href="https://doi.org/10.1111/1365-2664.13834"
- Description: Biological control (biocontrol) of invasive alien plants is a widely utilised weed management tool. Prospective biocontrol agents are typically assessed through host specificity testing and pre-release efficacy studies performed in quarantine. However, rearing of the potential biocontrol agents and/or test plants is often difficult or impossible under quarantine conditions. Moreover, practitioners may attain laboratory artefacts in quarantine, which may result in the potential agent being needlessly rejected. Field-based studies in the weed's indigenous distribution could overcome these issues.
- Full Text:
- Date Issued: 2021
- Authors: Sutton, Guy F , Canavan, Kim N , Day, Michael M , Paterson, Iain D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423756 , vital:72091 , xlink:href="https://doi.org/10.1111/1365-2664.13834"
- Description: Biological control (biocontrol) of invasive alien plants is a widely utilised weed management tool. Prospective biocontrol agents are typically assessed through host specificity testing and pre-release efficacy studies performed in quarantine. However, rearing of the potential biocontrol agents and/or test plants is often difficult or impossible under quarantine conditions. Moreover, practitioners may attain laboratory artefacts in quarantine, which may result in the potential agent being needlessly rejected. Field-based studies in the weed's indigenous distribution could overcome these issues.
- Full Text:
- Date Issued: 2021
New insights into the geographical distribution, ecology and conservation status of South Africa’s endemic Coastal Leaf-toed Gecko, Cryptactites peringueyi (Boulenger, 1910)
- Nicolau, Gary K, Petford, Melissa, Edwards, Shelley, Busschau, Theo, Lynch, Kier, Kemp, Luke, Balmer, Jonathan P, Keates, Chad, Hundermark, Courtney R, Weeber, Joshua, Conradie, Werner C
- Authors: Nicolau, Gary K , Petford, Melissa , Edwards, Shelley , Busschau, Theo , Lynch, Kier , Kemp, Luke , Balmer, Jonathan P , Keates, Chad , Hundermark, Courtney R , Weeber, Joshua , Conradie, Werner C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461517 , vital:76209 , xlink:href="https://www.biotaxa.org/hn/article/view/63908"
- Description: Range-restricted species are generally poorly known and at higher risk of extinction than species with wider distributions. In the past, the Coastal Leaf-toed Gecko, Cryptactites peringueyi (Boulenger, 1910) caused much confusion and was once referred to as “one of the herpetological mysteries of the region”. Knowledge on the species has grown substantially, predominately due to new insights into its ecological preferences. Surveys from 2018 through early 2020 re-established the presence of C. peringueyi at three of four historical localities, as well as documenting four new localities. In 2018, preliminary data from these surveys resulted in an IUCN Red List downgrading from Critically Endangered to Near Threatened. However, with further investigation into the distribution of the species, the results from the present study more than doubled the previously estimated Extent of Occurrence from 785 km2 to 1504 km2 and the populations appear to be stable, despite environmental and anthropogenic disturbance. By incorporating environmental niche modelling, we further discuss the distribution, habits and ecology of C. peringueyi. The results presented here highlight the importance of fully understanding a species’ ecology to address its conservation status and we suggest that a new listing of Least Concern is appropriate for C. peringueyi.
- Full Text:
- Date Issued: 2021
- Authors: Nicolau, Gary K , Petford, Melissa , Edwards, Shelley , Busschau, Theo , Lynch, Kier , Kemp, Luke , Balmer, Jonathan P , Keates, Chad , Hundermark, Courtney R , Weeber, Joshua , Conradie, Werner C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461517 , vital:76209 , xlink:href="https://www.biotaxa.org/hn/article/view/63908"
- Description: Range-restricted species are generally poorly known and at higher risk of extinction than species with wider distributions. In the past, the Coastal Leaf-toed Gecko, Cryptactites peringueyi (Boulenger, 1910) caused much confusion and was once referred to as “one of the herpetological mysteries of the region”. Knowledge on the species has grown substantially, predominately due to new insights into its ecological preferences. Surveys from 2018 through early 2020 re-established the presence of C. peringueyi at three of four historical localities, as well as documenting four new localities. In 2018, preliminary data from these surveys resulted in an IUCN Red List downgrading from Critically Endangered to Near Threatened. However, with further investigation into the distribution of the species, the results from the present study more than doubled the previously estimated Extent of Occurrence from 785 km2 to 1504 km2 and the populations appear to be stable, despite environmental and anthropogenic disturbance. By incorporating environmental niche modelling, we further discuss the distribution, habits and ecology of C. peringueyi. The results presented here highlight the importance of fully understanding a species’ ecology to address its conservation status and we suggest that a new listing of Least Concern is appropriate for C. peringueyi.
- Full Text:
- Date Issued: 2021
Photocatalytic desulfurization of dibenzothiophene using asymmetrical zinc (II) phthalocyanines conjugated to silver-magnetic nanoparticles
- Mgidlana, Sithi, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185953 , vital:44451 , xlink:href="https://doi.org/10.1016/j.ica.2020.119970"
- Description: Asymmetrical Zn(II) phthalocyanines: mono (4-carboxy phenoxy) tris (phenylazo phenoxy) (1), mono (4-amino phenoxy) tris (phenylazo phenoxy) (2), mono (4-propanoic acid phenoxy) tris (phenylazo phenoxy) (3) zinc(II) phthalocyanines are synthesized and covalently linked to mercaptohexanol (mph) or mercaptopropionic acid (mpa) functionalized dimerized silver-magnetic nanoparticles (Ag-M). Complexes 1 and 3 are covalently linked to nanomaterials via ester bond whereas complex 2 is covalently linked to nanoparticles (NPs) via amide bond. The conjugates of complexes 1–3 with NPs gave higher singlet oxygen quantum than the Pcs alone. Electrospun fibers were fabricated from polystyrene (PS) solutions containing complexes 1 to 3 and their conjugates. The functionalized PS fibers were used for the phototransformation of dibenzothiophene. The increase in photocatalytic properties of phthalocyanines was observed in the presence of Ag-M with 3 alone and its conjugate with mph capped silver-magnetic nanoparticles showing the larger catalytic activity towards the transformation of dibenzothiophene.
- Full Text:
- Date Issued: 2021
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185953 , vital:44451 , xlink:href="https://doi.org/10.1016/j.ica.2020.119970"
- Description: Asymmetrical Zn(II) phthalocyanines: mono (4-carboxy phenoxy) tris (phenylazo phenoxy) (1), mono (4-amino phenoxy) tris (phenylazo phenoxy) (2), mono (4-propanoic acid phenoxy) tris (phenylazo phenoxy) (3) zinc(II) phthalocyanines are synthesized and covalently linked to mercaptohexanol (mph) or mercaptopropionic acid (mpa) functionalized dimerized silver-magnetic nanoparticles (Ag-M). Complexes 1 and 3 are covalently linked to nanomaterials via ester bond whereas complex 2 is covalently linked to nanoparticles (NPs) via amide bond. The conjugates of complexes 1–3 with NPs gave higher singlet oxygen quantum than the Pcs alone. Electrospun fibers were fabricated from polystyrene (PS) solutions containing complexes 1 to 3 and their conjugates. The functionalized PS fibers were used for the phototransformation of dibenzothiophene. The increase in photocatalytic properties of phthalocyanines was observed in the presence of Ag-M with 3 alone and its conjugate with mph capped silver-magnetic nanoparticles showing the larger catalytic activity towards the transformation of dibenzothiophene.
- Full Text:
- Date Issued: 2021
Prevalence and clinical correlates of substance use disorders in South African Xhosa patients with schizophrenia
- Temmingh, Henk, Susser, Ezra, Mall, Sumaya, Campbell, Megan M, Sibeko, Goodman, Stein, Dan J
- Authors: Temmingh, Henk , Susser, Ezra , Mall, Sumaya , Campbell, Megan M , Sibeko, Goodman , Stein, Dan J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302509 , vital:58203 , xlink:href="https://doi.org/10.1007/s00127-020-01942-5"
- Description: Purpose: To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs. Methods: Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs. Results: In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Signifcant predictors of any SUD were younger age (41–55 vs. 21–30: OR=0.7, 95% CI=0.5–0.9), male sex (OR=8.6, 95% CI=5.1–14.6), inpatient status (OR=1.7, 95% CI=1.3–2.1), post-traumatic stress symptoms (OR=4.6, 95% CI=1.6–13.3), legal (OR=3.4, 95% CI=2.0–5.5) and economic problems (OR=1.4, 95% CI=1.0–2.0). Methamphetamine use disorders occurred signifcantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were signifcantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were signifcantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs. Conclusion: SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.
- Full Text:
- Date Issued: 2021
- Authors: Temmingh, Henk , Susser, Ezra , Mall, Sumaya , Campbell, Megan M , Sibeko, Goodman , Stein, Dan J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302509 , vital:58203 , xlink:href="https://doi.org/10.1007/s00127-020-01942-5"
- Description: Purpose: To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs. Methods: Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs. Results: In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Signifcant predictors of any SUD were younger age (41–55 vs. 21–30: OR=0.7, 95% CI=0.5–0.9), male sex (OR=8.6, 95% CI=5.1–14.6), inpatient status (OR=1.7, 95% CI=1.3–2.1), post-traumatic stress symptoms (OR=4.6, 95% CI=1.6–13.3), legal (OR=3.4, 95% CI=2.0–5.5) and economic problems (OR=1.4, 95% CI=1.0–2.0). Methamphetamine use disorders occurred signifcantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were signifcantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were signifcantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs. Conclusion: SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.
- Full Text:
- Date Issued: 2021
Reshaping our musical values: decolonising teaching and curricular frameworks in the Eastern Cape
- Authors: McConnachie, Boudina E
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/480216 , vital:78407 , xlink:href="https://doi.org/10.1080/17411912.2021.1930090"
- Description: Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. This short essay in an alternative format of a critical report records the development and implementation of an African instrumental music studies course at Rhodes University, introduced to re-value and promote African ways of making and interacting with music. As a result of in-depth research with regard to the ailing Indigenous African Music (IAM) syllabus in the South African national school music curriculum, this university-level course has been designed to generate future teachers and culture-bearers who will possess a deeper understanding of, and feeling for, Indigenous African musics and who, as a result, will be able to engage with African musics through teaching and learning. Highlighting the crisis in South African music education decolonisation, this paper will also present other proposed solutions to this problem.
- Full Text:
- Date Issued: 2021
- Authors: McConnachie, Boudina E
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/480216 , vital:78407 , xlink:href="https://doi.org/10.1080/17411912.2021.1930090"
- Description: Musical ideals set by European standards and values, entrenched through colonial oppression and promoted by the continued veneration of Western culture need to be re-evaluated. This short essay in an alternative format of a critical report records the development and implementation of an African instrumental music studies course at Rhodes University, introduced to re-value and promote African ways of making and interacting with music. As a result of in-depth research with regard to the ailing Indigenous African Music (IAM) syllabus in the South African national school music curriculum, this university-level course has been designed to generate future teachers and culture-bearers who will possess a deeper understanding of, and feeling for, Indigenous African musics and who, as a result, will be able to engage with African musics through teaching and learning. Highlighting the crisis in South African music education decolonisation, this paper will also present other proposed solutions to this problem.
- Full Text:
- Date Issued: 2021
Synthesis, theoretical calculations and laser flash photolysis studies of selected amphiphilic porphyrin derivatives used as biofilm photodegradative materials
- Openda, Yolande I, Ngoy, Bokolombe P, Muva, Jules T, Nyokong, Tebello
- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Muva, Jules T , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190589 , vital:45008 , xlink:href="https://doi.org/10.1039/D1NJ02651H"
- Description: Photodynamic antimicrobial activities of gallium and indium porphyrins as well as their quaternized derivatives have been investigated against S. aureus and E. coli biofilms, as well as on their planktonic (free floating) cells using a light emitting diode lamp at 415 nm. The studied photosensitizers show considerable ability to generate singlet oxygen and the quaternized molecules 2a and 3a are potential photodynamic antimicrobial chemotherapy (PACT) agents with log10 colony forming units >9 for E. coli and S. aureus planktonic cells. The quaternized derivatives are found to have higher ability to significantly suppress the biofilms of both S. aureus and E. coli in vitro. Therefore, this demonstrates that they are potentially suitable photosensitive agents for PACT use. The TD-B3LYP/LanL2DZ calculations were performed to evaluate the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. Our study shows excellent agreement between time-dependent density-functional theory (TD-DFT) excited energies and experimental S1 > S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-visible spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO−1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.
- Full Text:
- Date Issued: 2021
- Authors: Openda, Yolande I , Ngoy, Bokolombe P , Muva, Jules T , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190589 , vital:45008 , xlink:href="https://doi.org/10.1039/D1NJ02651H"
- Description: Photodynamic antimicrobial activities of gallium and indium porphyrins as well as their quaternized derivatives have been investigated against S. aureus and E. coli biofilms, as well as on their planktonic (free floating) cells using a light emitting diode lamp at 415 nm. The studied photosensitizers show considerable ability to generate singlet oxygen and the quaternized molecules 2a and 3a are potential photodynamic antimicrobial chemotherapy (PACT) agents with log10 colony forming units >9 for E. coli and S. aureus planktonic cells. The quaternized derivatives are found to have higher ability to significantly suppress the biofilms of both S. aureus and E. coli in vitro. Therefore, this demonstrates that they are potentially suitable photosensitive agents for PACT use. The TD-B3LYP/LanL2DZ calculations were performed to evaluate the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. Our study shows excellent agreement between time-dependent density-functional theory (TD-DFT) excited energies and experimental S1 > S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-visible spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO−1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states.
- Full Text:
- Date Issued: 2021
The antibody assisted detection of HER2 on a cobalt porphyrin binuclear framework and gold functionalized graphene quantum dots modified electrode
- Centane, Sixole, Nyokong, Tebello
- Authors: Centane, Sixole , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185931 , vital:44449 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.114908"
- Description: In this work a novel simple, inexpensive and highly sensitive approach for the antibody assisted detection of the human epidermal growth factor receptor 2 (HER2) is presented. Three sensors using carboxylic group containing gold functionalized graphene quantum dots (SNGQDs@AuNPs), CoP-BNF (cobalt porphyrin binuclear framework) and CoP-BNF/SNGQDs@AuNPs (the conjugate) nanocomposites on a GCE were designed. The sensors were fabricated by covalent immobilization of the antibody to the GCE via an amide bond. The modified GCE was characterized using cyclic voltammetry and impedance spectroscopy. The performance of the sensors was assessed using electrochemical impedance spectroscopy. The selective recognition of the antibody towards HER2 on the electrode led to an increase of the electron transfer resistance (Rct). The different modified electrodes had low detection limit values: 0.0327 ng/mL, 0.0454 ng/mL and 0.1072 ng/mL towards the detection of HER2. The sensors showed good stability and reproducibility. The sensors showed promising potential in clinical applicability, in the detection of HER2 protein in human serum.
- Full Text:
- Date Issued: 2021
- Authors: Centane, Sixole , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185931 , vital:44449 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.114908"
- Description: In this work a novel simple, inexpensive and highly sensitive approach for the antibody assisted detection of the human epidermal growth factor receptor 2 (HER2) is presented. Three sensors using carboxylic group containing gold functionalized graphene quantum dots (SNGQDs@AuNPs), CoP-BNF (cobalt porphyrin binuclear framework) and CoP-BNF/SNGQDs@AuNPs (the conjugate) nanocomposites on a GCE were designed. The sensors were fabricated by covalent immobilization of the antibody to the GCE via an amide bond. The modified GCE was characterized using cyclic voltammetry and impedance spectroscopy. The performance of the sensors was assessed using electrochemical impedance spectroscopy. The selective recognition of the antibody towards HER2 on the electrode led to an increase of the electron transfer resistance (Rct). The different modified electrodes had low detection limit values: 0.0327 ng/mL, 0.0454 ng/mL and 0.1072 ng/mL towards the detection of HER2. The sensors showed good stability and reproducibility. The sensors showed promising potential in clinical applicability, in the detection of HER2 protein in human serum.
- Full Text:
- Date Issued: 2021
The cicada genus Tugelana Distant, 1912 (Hemiptera, Cicadidae): phylogenetic position and conservation status
- Villet, Martin H, Edwards, Shelley
- Authors: Villet, Martin H , Edwards, Shelley
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461561 , vital:76213 , xlink:href="http://zoobank.org/9A40F791-5D6C-42A5-8D7F-6D8A7CA8A99E"
- Description: The cicada genus Tugelana Distant, 1912 is monotypic and endemic to south-eastern Africa. Material was not available for a recent molecular phylogeny of its tribe, so its precise phylogenetic placement is unestablished. Consequently, a 627 bp sequence of the cytochrome oxidase gene was obtained and its candidate relatives identified as several species of Platypleura Amyot and Audinet-Serville, 1843 using the BOLD Identification System and NCBI Genbank’s BLAST. Bayesian inference analyses indicated that the type species, the Maputaland Orangewing Cicada Tugelana butleri Distant, 1912, is closely related to the Dune Koko Orangewing Cicada Platypleura zuluensis Villet, 1989, which has a geographical distribution that is parapatric with T. butleri and which has aberrant genitalia for a member of Platypleura. This pair of species is placed fairly deep within the African clade of Platypleura. We therefore formally recognized Platypleura Amyot and Audinet-Serville, 1843 as a senior synonym of Tugelana Distant, 1912, syn. nov., and assign T. butleri Distant, 1912 to Platypleura as Platypleura butleri (Distant 1912), comb. nov. The species occurs on the wooded grasslands of the Maputaland coastal plateau east of Lebombo Mountains and south of Maputo Bay. Its Extent of Occurrence is about 6360 km2, which would qualify it as Vulnerable under the IUCN’s classification criteria for conservation status.
- Full Text:
- Date Issued: 2021
- Authors: Villet, Martin H , Edwards, Shelley
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461561 , vital:76213 , xlink:href="http://zoobank.org/9A40F791-5D6C-42A5-8D7F-6D8A7CA8A99E"
- Description: The cicada genus Tugelana Distant, 1912 is monotypic and endemic to south-eastern Africa. Material was not available for a recent molecular phylogeny of its tribe, so its precise phylogenetic placement is unestablished. Consequently, a 627 bp sequence of the cytochrome oxidase gene was obtained and its candidate relatives identified as several species of Platypleura Amyot and Audinet-Serville, 1843 using the BOLD Identification System and NCBI Genbank’s BLAST. Bayesian inference analyses indicated that the type species, the Maputaland Orangewing Cicada Tugelana butleri Distant, 1912, is closely related to the Dune Koko Orangewing Cicada Platypleura zuluensis Villet, 1989, which has a geographical distribution that is parapatric with T. butleri and which has aberrant genitalia for a member of Platypleura. This pair of species is placed fairly deep within the African clade of Platypleura. We therefore formally recognized Platypleura Amyot and Audinet-Serville, 1843 as a senior synonym of Tugelana Distant, 1912, syn. nov., and assign T. butleri Distant, 1912 to Platypleura as Platypleura butleri (Distant 1912), comb. nov. The species occurs on the wooded grasslands of the Maputaland coastal plateau east of Lebombo Mountains and south of Maputo Bay. Its Extent of Occurrence is about 6360 km2, which would qualify it as Vulnerable under the IUCN’s classification criteria for conservation status.
- Full Text:
- Date Issued: 2021
A novel gold (I)-mediated intramolecular transamidation of benzoyl thiourea derivatives to form benzamides via dethiocyanation
- Odame, Felix, Woodcock, Guillaume, Hosten, Eric C, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Woodcock, Guillaume , Hosten, Eric C , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446988 , vital:74575 , xlink:href="https://doi.org/10.1016/j.jorganchem.2020.121359"
- Description: A novel gold(I)-mediated intramolecular transamidation of thiourea derivatives to yield benzamides via dethiocyanation have been achieved by the reaction of 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea derivatives in the presence of gold(I) precursors. The compounds have been characterized using IR, NMR, GC-MS and microanalysis. The single crystal XRD of 3-(1,3-benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (5), 3-(1,3-benzothiazol-2-yl)-1-(3-methoxybenzoyl)thiourea (6), N-(benzothiazol-2-yl)benzamide (10), N-(benzothiazol-2-yl)-3-chlorobenzamide (11), N-(benzothiazol-2-yl)-4-nitrobenzamide (12), N-(benzothiazol-2-yl)-3-bromobenzamide (14) have been discussed. The novel transformation is thought to proceed by a gold(I)-mediated intramolecular transamidation reaction which releases thiocyanate to yield the benzamide. Density functional theory calculations have been used to support the proposed mechanism for this transformation.
- Full Text:
- Date Issued: 2020
- Authors: Odame, Felix , Woodcock, Guillaume , Hosten, Eric C , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446988 , vital:74575 , xlink:href="https://doi.org/10.1016/j.jorganchem.2020.121359"
- Description: A novel gold(I)-mediated intramolecular transamidation of thiourea derivatives to yield benzamides via dethiocyanation have been achieved by the reaction of 3-(1,3-benzothiazol-2-yl)-1-(benzoyl)thiourea derivatives in the presence of gold(I) precursors. The compounds have been characterized using IR, NMR, GC-MS and microanalysis. The single crystal XRD of 3-(1,3-benzothiazol-2-yl)-1-(3-bromobenzoyl)thiourea (5), 3-(1,3-benzothiazol-2-yl)-1-(3-methoxybenzoyl)thiourea (6), N-(benzothiazol-2-yl)benzamide (10), N-(benzothiazol-2-yl)-3-chlorobenzamide (11), N-(benzothiazol-2-yl)-4-nitrobenzamide (12), N-(benzothiazol-2-yl)-3-bromobenzamide (14) have been discussed. The novel transformation is thought to proceed by a gold(I)-mediated intramolecular transamidation reaction which releases thiocyanate to yield the benzamide. Density functional theory calculations have been used to support the proposed mechanism for this transformation.
- Full Text:
- Date Issued: 2020
An improved systems approach as a phytosanitary measure for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in export citrus fruit from South Africa
- Hattingh, Vaughan, Moore, Sean D, Kirkman, Wayne, Goddard, Mathew K, Thackeray, Sean R, Peyper, Mellissa, Sharp, Gary, Cronjé, Paul, Pringle, Ken
- Authors: Hattingh, Vaughan , Moore, Sean D , Kirkman, Wayne , Goddard, Mathew K , Thackeray, Sean R , Peyper, Mellissa , Sharp, Gary , Cronjé, Paul , Pringle, Ken
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423700 , vital:72086 , xlink:href="https://doi.org/10.1093/jee/toz336"
- Description: A systems approach was previously developed for mitigating phytosanitary risk of Thaumatotibia leucotreta (Meyrick) in citrus fruit exported from South Africa, as an alternative to a standalone cold disinfestation treatment. The present study first tested the original systems approach by applying it on a semicommercial scale in 10 Nova mandarin orchards. Fruit were inspected at points in the production, packing, and simulated shipping process, to assess performance of the systems approach. Additional data were obtained from 17 Valencia orange orchards and six packinghouses. In the second part of this study, the systems approach was accordingly revised and improved, consisting of three measures: 1) preharvest controls and measurements and postpicking sampling, inspection, and packinghouse procedures; 2) postpacking sampling and inspection; and 3) shipping conditions. The model quantifying the effectiveness of the systems approach was improved by correcting errors in the original version, updating parameter values and adding a component that provides for comparison with the risk mitigation provided by a standalone disinfestation treatment. Consequently, the maximum potential proportion of fruit that may be infested with live T. leucotreta after application of the improved systems approach is no greater than the proportion of fruit that may be infested after application of a Probit 9 efficacy postharvest disinfestation treatment to fruit with a 2% pretreatment infestation. The probability of a mating pair surviving is also determined. The model enables a priori determination of the required threshold levels for any of the three measures, based on quantification of the other two measures.
- Full Text:
- Date Issued: 2020
- Authors: Hattingh, Vaughan , Moore, Sean D , Kirkman, Wayne , Goddard, Mathew K , Thackeray, Sean R , Peyper, Mellissa , Sharp, Gary , Cronjé, Paul , Pringle, Ken
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423700 , vital:72086 , xlink:href="https://doi.org/10.1093/jee/toz336"
- Description: A systems approach was previously developed for mitigating phytosanitary risk of Thaumatotibia leucotreta (Meyrick) in citrus fruit exported from South Africa, as an alternative to a standalone cold disinfestation treatment. The present study first tested the original systems approach by applying it on a semicommercial scale in 10 Nova mandarin orchards. Fruit were inspected at points in the production, packing, and simulated shipping process, to assess performance of the systems approach. Additional data were obtained from 17 Valencia orange orchards and six packinghouses. In the second part of this study, the systems approach was accordingly revised and improved, consisting of three measures: 1) preharvest controls and measurements and postpicking sampling, inspection, and packinghouse procedures; 2) postpacking sampling and inspection; and 3) shipping conditions. The model quantifying the effectiveness of the systems approach was improved by correcting errors in the original version, updating parameter values and adding a component that provides for comparison with the risk mitigation provided by a standalone disinfestation treatment. Consequently, the maximum potential proportion of fruit that may be infested with live T. leucotreta after application of the improved systems approach is no greater than the proportion of fruit that may be infested after application of a Probit 9 efficacy postharvest disinfestation treatment to fruit with a 2% pretreatment infestation. The probability of a mating pair surviving is also determined. The model enables a priori determination of the required threshold levels for any of the three measures, based on quantification of the other two measures.
- Full Text:
- Date Issued: 2020
Biological control potential of ectomycorrhizal fungi against Fusarium circinatum on Pinus patula seedlings
- Chartier FitzGerald, Veronique C, Dames, Joanna F, Hawley, Grant L
- Authors: Chartier FitzGerald, Veronique C , Dames, Joanna F , Hawley, Grant L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425960 , vital:72302 , xlink:href="https://doi.org/10.1080/09583157.2020.1771542"
- Description: The South Africa forestry industry, covering ∼1.3 million hectares, is dependent on exotic pine and Eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess the effects of ectomycorrhizal fungal inoculation on Pinus patula seedling growth and resistance to the fungal pathogen F. circinatum. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates that were then verified via DNA extraction and PCR amplification and sequencing of the ITS rDNA region. These isolates were identified as Boletus edulis f. reticulatus, Lactarius quieticolor, Suillus granulatus and an unknown Suillus species. P. patula growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the L. quieticolor and Suillus isolates. Preventative inoculation of seedlings in the nursery using these isolates would ensure the production of stronger, healthier plants that would be more resistant to F. circinatum infection, increasing survival in the plantation.
- Full Text:
- Date Issued: 2020
- Authors: Chartier FitzGerald, Veronique C , Dames, Joanna F , Hawley, Grant L
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425960 , vital:72302 , xlink:href="https://doi.org/10.1080/09583157.2020.1771542"
- Description: The South Africa forestry industry, covering ∼1.3 million hectares, is dependent on exotic pine and Eucalyptus species. Nursery seedlings are not inoculated with ectomycorrhizal (ECM) fungi or other beneficial microbes. Fusarium circinatum is an economically important pathogen affecting seedling survival. The purpose of this investigation was to assess the effects of ectomycorrhizal fungal inoculation on Pinus patula seedling growth and resistance to the fungal pathogen F. circinatum. Explants from ECM basidiocarps, collected from Pinus stands, were plated onto MMN medium to obtain isolates that were then verified via DNA extraction and PCR amplification and sequencing of the ITS rDNA region. These isolates were identified as Boletus edulis f. reticulatus, Lactarius quieticolor, Suillus granulatus and an unknown Suillus species. P. patula growth in the presence of the pathogen F. circinatum was significantly increased and promoted by the L. quieticolor and Suillus isolates. Preventative inoculation of seedlings in the nursery using these isolates would ensure the production of stronger, healthier plants that would be more resistant to F. circinatum infection, increasing survival in the plantation.
- Full Text:
- Date Issued: 2020
Conserved bacterial genomes from two geographically isolated peritidal stromatolite formations shed light on potential functional guilds
- Waterworth, Samantha C, Isemonger, Eric W, Rees, Evan R, Dorrington, Rosemary A
- Authors: Waterworth, Samantha C , Isemonger, Eric W , Rees, Evan R , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429411 , vital:72608 , xlink:href="https://doi.org/10.1111/1758-2229.12916"
- Description: Stromatolites are complex microbial mats that form lithified layers. Fossilized stromatolites are the oldest evidence of cellular life on Earth, dating back over3.4 billion years. Modern stromatolites are relatively rare but may provide clues about the function and evolution of their ancient counterparts. In this study, we focus on peritidal stromatolites occurring at Cape Recife and Schoenmakerskop on the southeastern South African coastline, the former being morphologically and structurally similar to fossilized phosphatic stromatolites formations. Using assembled shotgun metagenomic analysis, we obtained 183 genomic bins, of which the most dominant taxa were from the Cyanobacteria phylum. We identified functional gene sets in genomic bins conserved across two geographically isolated stromatolite formations, which included relatively high copy numbers of genes involved in the reduction of nitrates and phosphatic compounds. Additionally, we found little evidence of Archaeal species in these stromatolites, suggesting that they may not play an important role in peritidal stromatolite formations, as proposed for hypersaline formations.
- Full Text:
- Date Issued: 2020
- Authors: Waterworth, Samantha C , Isemonger, Eric W , Rees, Evan R , Dorrington, Rosemary A
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429411 , vital:72608 , xlink:href="https://doi.org/10.1111/1758-2229.12916"
- Description: Stromatolites are complex microbial mats that form lithified layers. Fossilized stromatolites are the oldest evidence of cellular life on Earth, dating back over3.4 billion years. Modern stromatolites are relatively rare but may provide clues about the function and evolution of their ancient counterparts. In this study, we focus on peritidal stromatolites occurring at Cape Recife and Schoenmakerskop on the southeastern South African coastline, the former being morphologically and structurally similar to fossilized phosphatic stromatolites formations. Using assembled shotgun metagenomic analysis, we obtained 183 genomic bins, of which the most dominant taxa were from the Cyanobacteria phylum. We identified functional gene sets in genomic bins conserved across two geographically isolated stromatolite formations, which included relatively high copy numbers of genes involved in the reduction of nitrates and phosphatic compounds. Additionally, we found little evidence of Archaeal species in these stromatolites, suggesting that they may not play an important role in peritidal stromatolite formations, as proposed for hypersaline formations.
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- Date Issued: 2020