Synthesis of pH sensitive dual capped CdTe QDs: their optical properties and structural morphology
- Daramola, Olamide A, Noundou, Xavier S, Nkanga, Christian I, Tseki, Potlaki F, Krause, Rui W M
- Authors: Daramola, Olamide A , Noundou, Xavier S , Nkanga, Christian I , Tseki, Potlaki F , Krause, Rui W M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156364 , vital:39983 , https://doi.org/10.1007/s10895-020-02526-x
- Description: We herein report five different types of thiol dual capped cadmium tellurite quantum dots (CdTe QDs) namely glutathionemercapto-propanoic acid (QD 1), glutathione-thiolglycolic acid (QD 2), L-cysteine-mercapto-propanoic acid (QD 3), L-cysteinethiol-glycolic acid (QD 4) and mercapto-propanoic acid-thiol-glycolic (QD 5). Dual-capped CdTe QDs were prepared using a one pot synthetic method. Cadmium acetate and sodium tellurite were respectively used as cadmium and tellurium precursors. Photo-physical properties of the synthesized QDs were examined using UV-Vis and photoluminescence spectroscopy while structural characterization was performed by means of transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy.
- Full Text:
- Date Issued: 2020
- Authors: Daramola, Olamide A , Noundou, Xavier S , Nkanga, Christian I , Tseki, Potlaki F , Krause, Rui W M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156364 , vital:39983 , https://doi.org/10.1007/s10895-020-02526-x
- Description: We herein report five different types of thiol dual capped cadmium tellurite quantum dots (CdTe QDs) namely glutathionemercapto-propanoic acid (QD 1), glutathione-thiolglycolic acid (QD 2), L-cysteine-mercapto-propanoic acid (QD 3), L-cysteinethiol-glycolic acid (QD 4) and mercapto-propanoic acid-thiol-glycolic (QD 5). Dual-capped CdTe QDs were prepared using a one pot synthetic method. Cadmium acetate and sodium tellurite were respectively used as cadmium and tellurium precursors. Photo-physical properties of the synthesized QDs were examined using UV-Vis and photoluminescence spectroscopy while structural characterization was performed by means of transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy.
- Full Text:
- Date Issued: 2020
The Northern Cross fast radio burst project–I: overview and pilot observations at 408 MHz
- Locatelli, Nicola T, Bernardi, Gianni, Bianchi, Germano, Chiello, Riccardo C, Magro, Alessio, Naldi, Giovanni, Pilia, Maura, Pupillo, Giuseppe, Ridolfi, Alessandro, Setti, Giancarlo, Vazza, Franco
- Authors: Locatelli, Nicola T , Bernardi, Gianni , Bianchi, Germano , Chiello, Riccardo C , Magro, Alessio , Naldi, Giovanni , Pilia, Maura , Pupillo, Giuseppe , Ridolfi, Alessandro , Setti, Giancarlo , Vazza, Franco
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148791 , vital:38774 , https://0-doi.org.wam.seals.ac.za/10.1093/mnras/staa813
- Description: Fast radio bursts (FRBs) remain one of the most enigmatic astrophysical sources. Observations have significantly progressed over the last few years, due to the capabilities of new radio telescopes and the refurbishment of existing ones. Here, we describe the upgrade of the Northern Cross radio telescope, operating in the 400–416 MHz frequency band, with the ultimate goal of turning the array into a dedicated instrument to survey the sky for FRBs.
- Full Text:
- Date Issued: 2020
- Authors: Locatelli, Nicola T , Bernardi, Gianni , Bianchi, Germano , Chiello, Riccardo C , Magro, Alessio , Naldi, Giovanni , Pilia, Maura , Pupillo, Giuseppe , Ridolfi, Alessandro , Setti, Giancarlo , Vazza, Franco
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148791 , vital:38774 , https://0-doi.org.wam.seals.ac.za/10.1093/mnras/staa813
- Description: Fast radio bursts (FRBs) remain one of the most enigmatic astrophysical sources. Observations have significantly progressed over the last few years, due to the capabilities of new radio telescopes and the refurbishment of existing ones. Here, we describe the upgrade of the Northern Cross radio telescope, operating in the 400–416 MHz frequency band, with the ultimate goal of turning the array into a dedicated instrument to survey the sky for FRBs.
- Full Text:
- Date Issued: 2020
The Thousand-Pulsar-Array programme on MeerKAT–I: science objectives and first results
- Johnston, Simon, Karastergiou, A, Keith, M J, Song, X, Weltevrede, P, Abbate, F, Bailes, M, Buchner, S, Camilo, F, Geyer, M, Hugo, B, Jameson, A, Kramer, M, Parthasarathy, A, Reardon, D J, Ridolfi A, Serylak, M, Shannon, R M, Spiewak, R, Van Straten, W, Venkatraman Krishnan, V, Jankowski, F, Meyers, B W, Oswald , L, Posselt, B, Sobey, C, Szary, A, Van Leeuwen, J
- Authors: Johnston, Simon , Karastergiou, A , Keith, M J , Song, X , Weltevrede, P , Abbate, F , Bailes, M , Buchner, S , Camilo, F , Geyer, M , Hugo, B , Jameson, A , Kramer, M , Parthasarathy, A , Reardon, D J , Ridolfi A , Serylak, M , Shannon, R M , Spiewak, R , Van Straten, W , Venkatraman Krishnan, V , Jankowski, F , Meyers, B W , Oswald , L , Posselt, B , Sobey, C , Szary, A , Van Leeuwen, J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148814 , vital:38776 , https://0-doi.org.wam.seals.ac.za/10.1093/mnras/staa516
- Description: We report here on initial results from the Thousand-Pulsar-Array (TPA) programme, part of the Large Survey Project ‘MeerTime’ on the MeerKAT telescope. The interferometer is used in the tied-array mode in the band from 856 to 1712 MHz, and the wide band coupled with the large collecting area and low receiver temperature make it an excellent telescope for the study of radio pulsars. The TPA is a 5 year project, which aims at to observing (a) more than 1000 pulsars to obtain high-fidelity pulse profiles, (b) some 500 of these pulsars over multiple epochs, and (c) long sequences of single-pulse trains from several hundred pulsars.
- Full Text:
- Date Issued: 2020
- Authors: Johnston, Simon , Karastergiou, A , Keith, M J , Song, X , Weltevrede, P , Abbate, F , Bailes, M , Buchner, S , Camilo, F , Geyer, M , Hugo, B , Jameson, A , Kramer, M , Parthasarathy, A , Reardon, D J , Ridolfi A , Serylak, M , Shannon, R M , Spiewak, R , Van Straten, W , Venkatraman Krishnan, V , Jankowski, F , Meyers, B W , Oswald , L , Posselt, B , Sobey, C , Szary, A , Van Leeuwen, J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148814 , vital:38776 , https://0-doi.org.wam.seals.ac.za/10.1093/mnras/staa516
- Description: We report here on initial results from the Thousand-Pulsar-Array (TPA) programme, part of the Large Survey Project ‘MeerTime’ on the MeerKAT telescope. The interferometer is used in the tied-array mode in the band from 856 to 1712 MHz, and the wide band coupled with the large collecting area and low receiver temperature make it an excellent telescope for the study of radio pulsars. The TPA is a 5 year project, which aims at to observing (a) more than 1000 pulsars to obtain high-fidelity pulse profiles, (b) some 500 of these pulsars over multiple epochs, and (c) long sequences of single-pulse trains from several hundred pulsars.
- Full Text:
- Date Issued: 2020
A tree cannot make a forest: looking inward, reaching out in African Art Studies
- Authors: Fọlárànmí, Stephen
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146090 , vital:38494 , https://0-doi.org.wam.seals.ac.za/10.1162/afar_a_00453
- Description: These proverbs from the Yorùbá of southwestern Nigeria and the Bemba of Zambia are a few examples that can be found in many Africa languages. While these proverbs are rich in philosophical sayings and muses, many are being forgotten because fewer and fewer people possess deep knowledge of languages, and in the arts, Africans tend to look to the Global North for theoretical frameworks to examine their art and other cultural properties. The title of this piece is therefore an identification with the potency of the proverbs because of the trends of collaboration that I have noticed in the last few years in African Art Studies. It could also be said to be a call to look into what could be shared within Global Souths in terms of an available knowledge base that could be used to forge ahead rather than subjecting thoughts and knowledge to the Global North.
- Full Text:
- Date Issued: 2019
- Authors: Fọlárànmí, Stephen
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146090 , vital:38494 , https://0-doi.org.wam.seals.ac.za/10.1162/afar_a_00453
- Description: These proverbs from the Yorùbá of southwestern Nigeria and the Bemba of Zambia are a few examples that can be found in many Africa languages. While these proverbs are rich in philosophical sayings and muses, many are being forgotten because fewer and fewer people possess deep knowledge of languages, and in the arts, Africans tend to look to the Global North for theoretical frameworks to examine their art and other cultural properties. The title of this piece is therefore an identification with the potency of the proverbs because of the trends of collaboration that I have noticed in the last few years in African Art Studies. It could also be said to be a call to look into what could be shared within Global Souths in terms of an available knowledge base that could be used to forge ahead rather than subjecting thoughts and knowledge to the Global North.
- Full Text:
- Date Issued: 2019
An experimental test of the allotonic frequency hypothesis to isolate the effects of light pollution on bat prey selection:
- Bailey, Lauren A, Brigham, R Mark, Bohn, Shelby J, Boyles, Justin G, Smit, Ben
- Authors: Bailey, Lauren A , Brigham, R Mark , Bohn, Shelby J , Boyles, Justin G , Smit, Ben
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158309 , vital:40171 , https://0-doi.org.wam.seals.ac.za/10.1007/s00442-019-04417-w
- Description: Artificial lights may be altering interactions between bats and moth prey. According to the allotonic frequency hypothesis (AFH), eared moths are generally unavailable as prey for syntonic bats (i.e., bats that use echolocation frequencies between 20 and 50 kHz within the hearing range of eared moths) due to the moths’ ability to detect syntonic bat echolocation. Syntonic bats therefore feed mainly on beetles, flies, true bugs, and non-eared moths. The AFH is expected to be violated around lights where eared moths are susceptible to exploitation by syntonic bats because moths’ evasive strategies become less effective. The hypothesis has been tested to date almost exclusively in areas with permanent lighting, where the effects of lights on bat diets are confounded with other aspects of human habitat alteration. We undertook diet analysis in areas with short-term, localized artificial lighting to isolate the effects of artificial lighting and determine if syntonic and allotonic bats (i.e., bats that use echolocation frequencies outside the hearing range of eared moths) consumed more moths under conditions of artificial lights than in natural darkness.
- Full Text:
- Date Issued: 2019
- Authors: Bailey, Lauren A , Brigham, R Mark , Bohn, Shelby J , Boyles, Justin G , Smit, Ben
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158309 , vital:40171 , https://0-doi.org.wam.seals.ac.za/10.1007/s00442-019-04417-w
- Description: Artificial lights may be altering interactions between bats and moth prey. According to the allotonic frequency hypothesis (AFH), eared moths are generally unavailable as prey for syntonic bats (i.e., bats that use echolocation frequencies between 20 and 50 kHz within the hearing range of eared moths) due to the moths’ ability to detect syntonic bat echolocation. Syntonic bats therefore feed mainly on beetles, flies, true bugs, and non-eared moths. The AFH is expected to be violated around lights where eared moths are susceptible to exploitation by syntonic bats because moths’ evasive strategies become less effective. The hypothesis has been tested to date almost exclusively in areas with permanent lighting, where the effects of lights on bat diets are confounded with other aspects of human habitat alteration. We undertook diet analysis in areas with short-term, localized artificial lighting to isolate the effects of artificial lighting and determine if syntonic and allotonic bats (i.e., bats that use echolocation frequencies outside the hearing range of eared moths) consumed more moths under conditions of artificial lights than in natural darkness.
- Full Text:
- Date Issued: 2019
Chinese engagement of Zimbabwe and the limits of elite agency:
- Chipaike, Ronald, Bischoff, Paul, 1954-
- Authors: Chipaike, Ronald , Bischoff, Paul, 1954-
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161548 , vital:40637 , https://0-doi.org.wam.seals.ac.za/10.1177/0021909619848783
- Description: This article contends that Zimbabwe’s agency in its engagement with China has been limited and at best circumscribed. This owes to factors such as indifference by state authorities to cooperation with civil society actors in negotiating with Chinese actors, the desperation of the The Zimbabwe African National Union – Patriotic Front regime in the face of isolation by erstwhile partners as well as the opacity and secrecy that characterizes significant areas of the Zimbabwe–China relationship. The pressing need for critical institutions such as parliament to play independent oversight roles as well as the creation of space for civil society watchdog functions are highlighted as key enablers if Zimbabwean agency is to generate positive gains from the country’s engagement with China.
- Full Text:
- Date Issued: 2019
- Authors: Chipaike, Ronald , Bischoff, Paul, 1954-
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161548 , vital:40637 , https://0-doi.org.wam.seals.ac.za/10.1177/0021909619848783
- Description: This article contends that Zimbabwe’s agency in its engagement with China has been limited and at best circumscribed. This owes to factors such as indifference by state authorities to cooperation with civil society actors in negotiating with Chinese actors, the desperation of the The Zimbabwe African National Union – Patriotic Front regime in the face of isolation by erstwhile partners as well as the opacity and secrecy that characterizes significant areas of the Zimbabwe–China relationship. The pressing need for critical institutions such as parliament to play independent oversight roles as well as the creation of space for civil society watchdog functions are highlighted as key enablers if Zimbabwean agency is to generate positive gains from the country’s engagement with China.
- Full Text:
- Date Issued: 2019
Condition Report 3: Art History in Africa: debating localization,legitimization and new solidarities
- Simbao, Ruth K, Kouoh, Koyo, Nzewi, Ugochukwu-Smooth C, Sousa, Suzana, Koide, Emi
- Authors: Simbao, Ruth K , Kouoh, Koyo , Nzewi, Ugochukwu-Smooth C , Sousa, Suzana , Koide, Emi
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146055 , vital:38491 , https://0-doi.org.wam.seals.ac.za/10.1162/afar_a_00456
- Description: Following on from the African Arts dialogue, “Zimbabwe Mobilizes: ICAC's Shift from Coup de Grăce to Cultural Coup” (Simbao et al. 2017) this dialogue considers another important event in the visual arts that recently took place on the African continent. Like the International Conference on African Cultures (ICAC) that was held in Harare in 2017, this event in Dakar contributes in important ways towards a shift of the center of gravity of the global academy, particularly the study of art history in and of Africa.
- Full Text:
- Date Issued: 2019
Condition Report 3: Art History in Africa: debating localization,legitimization and new solidarities
- Authors: Simbao, Ruth K , Kouoh, Koyo , Nzewi, Ugochukwu-Smooth C , Sousa, Suzana , Koide, Emi
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146055 , vital:38491 , https://0-doi.org.wam.seals.ac.za/10.1162/afar_a_00456
- Description: Following on from the African Arts dialogue, “Zimbabwe Mobilizes: ICAC's Shift from Coup de Grăce to Cultural Coup” (Simbao et al. 2017) this dialogue considers another important event in the visual arts that recently took place on the African continent. Like the International Conference on African Cultures (ICAC) that was held in Harare in 2017, this event in Dakar contributes in important ways towards a shift of the center of gravity of the global academy, particularly the study of art history in and of Africa.
- Full Text:
- Date Issued: 2019
Humor, innovation, and competition in Jamaican music:
- Authors: Stanley Niaah, Sonjah
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146398 , vital:38522 , ISBN 9781351266628
- Description: Book abstract. An essential part of human expression, humor plays a role in all forms of art, and humorous and comedic aspects have always been part of popular music. For the first time, The Routledge Companion to Popular Music and Humor draws together scholarship exploring how the element of humor interacts with the artistic and social aspects of the musical experience. Discussing humor in popular music across eras from Tin Pan Alley to the present, and examining the role of humor in different musical genres, case studies of artists, and media forms, this volume is a groundbreaking collection that provides a go-to reference for scholars in music, popular culture, and media studies.
- Full Text:
- Date Issued: 2019
- Authors: Stanley Niaah, Sonjah
- Date: 2019
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/146398 , vital:38522 , ISBN 9781351266628
- Description: Book abstract. An essential part of human expression, humor plays a role in all forms of art, and humorous and comedic aspects have always been part of popular music. For the first time, The Routledge Companion to Popular Music and Humor draws together scholarship exploring how the element of humor interacts with the artistic and social aspects of the musical experience. Discussing humor in popular music across eras from Tin Pan Alley to the present, and examining the role of humor in different musical genres, case studies of artists, and media forms, this volume is a groundbreaking collection that provides a go-to reference for scholars in music, popular culture, and media studies.
- Full Text:
- Date Issued: 2019
Improving TB infection control in a regional hospital in the Eastern Cape, South Africa
- Haeusler, Ilsa Louisa, Knights, Felicity, George, Vishaal, Parrish, Andy
- Authors: Haeusler, Ilsa Louisa , Knights, Felicity , George, Vishaal , Parrish, Andy
- Date: 2019
- Subjects: Quality circles Tuberculosis--Prevention Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6399 , vital:45465 , https://doi.org/10.4102/hts.v77i2.6828
- Description: This quality improvement (QI) work was carried out in Cecilia Makiwane Hospital (CMH), a regional public hospital in the Eastern Cape, South Africa (SA). SA has among the highest incidence of tuberculosis (TB) in the world and this is a leading cause of death in SA. Nosocomial infection is an important source of TB transmission. Adherence to TB infection prevention control (IPC) measures in the medical inpatient department was suboptimal at CMH. The overall aim of this QI project was to make sustainable improvements in TB IPC. A multidisciplinary team was formed to undertake a root cause analysis and develop a strategy for change. The main barriers to adherence to IPC measures were limited knowledge of IPC methods and stigma associated with TB. Specifically, the project aimed to increase the number of: ‘airborne precaution’ signs placed above patients’ beds, patients correctly isolated and patients wearing surgical face masks. Four Plan Do-Study-Act cycles were used. The strategy for change involved education and awareness-raising in different formats, including formal in-service training delivered to nurses and doctors, a hospital-wide TB awareness week with engaging activities and competitions, and a World TB Day provincial solidarity march. Data on adherence to the three IPC measures were collected over an 8-month period. Pre-intervention (October 2016), a mean of 2 percent of patients wore face masks, 22 percent were correctly isolated and 12 percent had an airborne precaution sign. Postintervention (May 2017), the compliance improved to 17 percent, 50 percent and 25 percent, respectively. There was a large variation in compliance to each measure. Improvement was greatest in the number of patients correctly isolated. We learnt it is important to work with, not in parallel to, existing teams or structures during QI work. On-the-ground training of nurses and clinicians should be undertaken alongside engagement of senior staff members and managers. This improves the chance of change being adopted into hospital policy.
- Full Text:
- Date Issued: 2019
- Authors: Haeusler, Ilsa Louisa , Knights, Felicity , George, Vishaal , Parrish, Andy
- Date: 2019
- Subjects: Quality circles Tuberculosis--Prevention Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6399 , vital:45465 , https://doi.org/10.4102/hts.v77i2.6828
- Description: This quality improvement (QI) work was carried out in Cecilia Makiwane Hospital (CMH), a regional public hospital in the Eastern Cape, South Africa (SA). SA has among the highest incidence of tuberculosis (TB) in the world and this is a leading cause of death in SA. Nosocomial infection is an important source of TB transmission. Adherence to TB infection prevention control (IPC) measures in the medical inpatient department was suboptimal at CMH. The overall aim of this QI project was to make sustainable improvements in TB IPC. A multidisciplinary team was formed to undertake a root cause analysis and develop a strategy for change. The main barriers to adherence to IPC measures were limited knowledge of IPC methods and stigma associated with TB. Specifically, the project aimed to increase the number of: ‘airborne precaution’ signs placed above patients’ beds, patients correctly isolated and patients wearing surgical face masks. Four Plan Do-Study-Act cycles were used. The strategy for change involved education and awareness-raising in different formats, including formal in-service training delivered to nurses and doctors, a hospital-wide TB awareness week with engaging activities and competitions, and a World TB Day provincial solidarity march. Data on adherence to the three IPC measures were collected over an 8-month period. Pre-intervention (October 2016), a mean of 2 percent of patients wore face masks, 22 percent were correctly isolated and 12 percent had an airborne precaution sign. Postintervention (May 2017), the compliance improved to 17 percent, 50 percent and 25 percent, respectively. There was a large variation in compliance to each measure. Improvement was greatest in the number of patients correctly isolated. We learnt it is important to work with, not in parallel to, existing teams or structures during QI work. On-the-ground training of nurses and clinicians should be undertaken alongside engagement of senior staff members and managers. This improves the chance of change being adopted into hospital policy.
- Full Text:
- Date Issued: 2019
Masked in metaphors: counter narratives in the works of Nigerian cartoonist Mike Asukwo
- Authors: Jimoh, Ganiyu A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145974 , vital:38483 , https://0-doi.org.wam.seals.ac.za/10.1162/afar_a_00458
- Description: At the time of independence, most African countries were poised to take charge of their own affairs. However, postcolonial realities characterized by political upheavals, coups and counter-coups, civil wars, and economic downturn, among other setbacks, created a sense of ambivalence in terms of political and economic freedom. In Nigeria, satirical expressions became the tool used against oppressive regimes. In post-independence Nigeria, from the military dictatorial era to the present civilian dispensations,1 sociopolitical issues have been lampooned in different forms of expression such as music, performance, cartoons, and memes. Within this environment, political cartoons began to thrive, as they became a relatively safe way to comment on the political issues of the day (Akande 2002: 2). This was achieved largely by concealing the main subject matter behind the “masks” of metaphoric imagery, which enabled cartoonists to develop narratives that counter the dominant narratives, often opposing governmental policies and practices.
- Full Text:
- Date Issued: 2019
- Authors: Jimoh, Ganiyu A
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145974 , vital:38483 , https://0-doi.org.wam.seals.ac.za/10.1162/afar_a_00458
- Description: At the time of independence, most African countries were poised to take charge of their own affairs. However, postcolonial realities characterized by political upheavals, coups and counter-coups, civil wars, and economic downturn, among other setbacks, created a sense of ambivalence in terms of political and economic freedom. In Nigeria, satirical expressions became the tool used against oppressive regimes. In post-independence Nigeria, from the military dictatorial era to the present civilian dispensations,1 sociopolitical issues have been lampooned in different forms of expression such as music, performance, cartoons, and memes. Within this environment, political cartoons began to thrive, as they became a relatively safe way to comment on the political issues of the day (Akande 2002: 2). This was achieved largely by concealing the main subject matter behind the “masks” of metaphoric imagery, which enabled cartoonists to develop narratives that counter the dominant narratives, often opposing governmental policies and practices.
- Full Text:
- Date Issued: 2019
Molecular identification and antibacterial properties of an ericoid associated mycorrhizal fungus
- Adeoyo, Olusegun R, Pletschke, Brett I, Dames, Joanna F
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440378 , vital:73778 , https://doi.org/10.1186/s12866-019-1555-y
- Description: The quest for novel sources of antibacterial compounds have necessitated the inclusion of ericoid mycorrhizal fungi (ERM) commonly found within the root of ericaceous plants. Agar-well diffusion method was used to detect antibacterial activity and was followed by the microbroth diffusion method [minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)].
- Full Text:
- Date Issued: 2019
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440378 , vital:73778 , https://doi.org/10.1186/s12866-019-1555-y
- Description: The quest for novel sources of antibacterial compounds have necessitated the inclusion of ericoid mycorrhizal fungi (ERM) commonly found within the root of ericaceous plants. Agar-well diffusion method was used to detect antibacterial activity and was followed by the microbroth diffusion method [minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)].
- Full Text:
- Date Issued: 2019
Spatial and Seasonal Distribution of Forensically Important Blow Flies (Diptera: Calliphoridae) in Makhanda, Eastern Cape, South Africa:
- Williams, Kirstin A, Villet, Martin H
- Authors: Williams, Kirstin A , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140716 , vital:37912 , DOI: 10.1093/jme/tjz056
- Description: The seasonal activity of adults of eight forensically important blow fly species [Calliphora croceipalpis (Diptera: Calliphoridae), Jaennicke, Lucilia sericata (Meigen) (Diptera: Calliphoridae), L. cuprina (Wiedemann) (Diptera: Calliphoridae), Chrysomya chloropyga (Wiedemann) (Diptera: Calliphoridae), Ch. albiceps (Wiedemann) (Diptera: Calliphoridae), Ch. marginalis (Wiedemann) (Diptera: Calliphoridae), Ch. putoria (Wiedemann) (Diptera: Calliphoridae), Ch. megacephala (Fabricius) (Diptera: Calliphoridae)] was quantified from collections in Makhanda, South Africa. Flies were collected in traps baited with chicken liver and placed in the field at eight locations for four consecutive days each fortnight for 14 mo. The seasonal distribution of each species compared well to published seasonal distributions of these blow flies elsewhere in South Africa, with evidence of year-to-year variation within seasons that might be explained by weather. This information is important for determining when and where certain species are likely to occur and will be of use in forensic investigations and myiasis management plans.
- Full Text:
- Date Issued: 2019
- Authors: Williams, Kirstin A , Villet, Martin H
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140716 , vital:37912 , DOI: 10.1093/jme/tjz056
- Description: The seasonal activity of adults of eight forensically important blow fly species [Calliphora croceipalpis (Diptera: Calliphoridae), Jaennicke, Lucilia sericata (Meigen) (Diptera: Calliphoridae), L. cuprina (Wiedemann) (Diptera: Calliphoridae), Chrysomya chloropyga (Wiedemann) (Diptera: Calliphoridae), Ch. albiceps (Wiedemann) (Diptera: Calliphoridae), Ch. marginalis (Wiedemann) (Diptera: Calliphoridae), Ch. putoria (Wiedemann) (Diptera: Calliphoridae), Ch. megacephala (Fabricius) (Diptera: Calliphoridae)] was quantified from collections in Makhanda, South Africa. Flies were collected in traps baited with chicken liver and placed in the field at eight locations for four consecutive days each fortnight for 14 mo. The seasonal distribution of each species compared well to published seasonal distributions of these blow flies elsewhere in South Africa, with evidence of year-to-year variation within seasons that might be explained by weather. This information is important for determining when and where certain species are likely to occur and will be of use in forensic investigations and myiasis management plans.
- Full Text:
- Date Issued: 2019
Synthesis of N-Substituted phosphoramidic acid esters as “reverse” fosmidomycin analogues
- Adeyemi, Christiana M, Hoppe, Heinrich C, Isaacs, Michelle, Klein, Rosalyn, Lobb, Kevin A, Kaye, Perry T
- Authors: Adeyemi, Christiana M , Hoppe, Heinrich C , Isaacs, Michelle , Klein, Rosalyn , Lobb, Kevin A , Kaye, Perry T
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443238 , vital:74101 , https://doi.org/10.1016/j.tet.2019.02.003
- Description: An efficient synthetic pathway to a series of novel “reverse” fosmidomycin analogues has been developed, commencing from substituted benzylamines. In these analogues, the fosmidomycin hydroxamate moiety is reversed and the tetrahedral methylene carbon adjacent to the phosphonate moiety is replaced by a nitrogen atom bearing different benzyl groups. The resulting phosphonate esters were designed as potential antimalarial “pro-drugs”.
- Full Text:
- Date Issued: 2019
- Authors: Adeyemi, Christiana M , Hoppe, Heinrich C , Isaacs, Michelle , Klein, Rosalyn , Lobb, Kevin A , Kaye, Perry T
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443238 , vital:74101 , https://doi.org/10.1016/j.tet.2019.02.003
- Description: An efficient synthetic pathway to a series of novel “reverse” fosmidomycin analogues has been developed, commencing from substituted benzylamines. In these analogues, the fosmidomycin hydroxamate moiety is reversed and the tetrahedral methylene carbon adjacent to the phosphonate moiety is replaced by a nitrogen atom bearing different benzyl groups. The resulting phosphonate esters were designed as potential antimalarial “pro-drugs”.
- Full Text:
- Date Issued: 2019
Acute toxicity study and prevention of Nω-nitro-L-arginine methyl ester-induced hypertension by Osteopermum imbricatum
- Tata, Charlotte, M, Gwebu, Ephraim, T, Olukayode O Aremu, Nkeh-Chungag, Benedicta, N, Oyedeji, Adebola, O, Oyedeji, Opeopluwa, O, Sewani-Rusike, Constance, R
- Authors: Tata, Charlotte, M , Gwebu, Ephraim, T , Olukayode O Aremu , Nkeh-Chungag, Benedicta, N , Oyedeji, Adebola, O , Oyedeji, Opeopluwa, O , Sewani-Rusike, Constance, R
- Date: June-2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4915 , vital:44303 , https://www.ajol.info/index.php/tjpr/article/view/174343
- Description: Purpose:To determine the phytochemical content, toxicity and hypertension prevention effects of Osteospermum imbricatum leaf and root extracts.Methods:Phytochemical screening of leaf and root extracts of O. imbricatum was performed by colorimetric procedure. Acute toxicity of leaf and root extracts was conductedin two phases; phase I consisted of three groups of mice (n = 3) for each dose level of 10, 100 and 1000 mg/kg while phase II had three mice that received 1600, 2900 or 5000 mg/kg. Wistar rats were grouped into 7 groups that were co-treated with L-NAME and normal saline or L-NAME and hydroethanolic leaf extract (150 and 300 mg/kg) or L-NAME and hydroethanolic root extract (150 and 300 mg/kg) or L-NAME and amlodipine (5 mg/kg) or normal saline only for 4 weeks. Treatment was carried out via the oral route while blood pressure was measured weeklyfor 4 weeks by non-invasive tail cuff method.Results:The phytochemical profile of the leaf and root extracts revealed the presence of phenols, terpenoids, flavonoids, glycosides, tannins, steroids and saponins. Both the leaf and root extracts were toxic at 5000 mg/kg with an LD50of 3807.89 mg/kg. In the fourth week of the study, only the leaf extract significantly (p less 0.01) prevented the progression of L-NAME induced hypertension; systolic and diastolic blood pressure of the group treated with L-NAME and leaf extract (300 mg/kg) were 183 ± 1 and 140 ± 1 mmHg, respectively, compared to the group that was treated with L-NAME and normal saline which produced systolic and diastolic BP values of 213 ± 3 and 172 ± 4 mmHg, respectively. The extracts, especially OIR300, exhibited diuretic effects in the second and third week of study by promoting excretion of 16 and 19 ml urine, respectively, compared to 11 and 14 ml for LN group.Conclusion:The results suggest that O. imbricatum is moderately toxic at a high dose and contains a wide range of phytochemicals which offer partial protection against the development of nitric oxide deficiency hypertension.
- Full Text:
- Date Issued: June-2018
- Authors: Tata, Charlotte, M , Gwebu, Ephraim, T , Olukayode O Aremu , Nkeh-Chungag, Benedicta, N , Oyedeji, Adebola, O , Oyedeji, Opeopluwa, O , Sewani-Rusike, Constance, R
- Date: June-2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4915 , vital:44303 , https://www.ajol.info/index.php/tjpr/article/view/174343
- Description: Purpose:To determine the phytochemical content, toxicity and hypertension prevention effects of Osteospermum imbricatum leaf and root extracts.Methods:Phytochemical screening of leaf and root extracts of O. imbricatum was performed by colorimetric procedure. Acute toxicity of leaf and root extracts was conductedin two phases; phase I consisted of three groups of mice (n = 3) for each dose level of 10, 100 and 1000 mg/kg while phase II had three mice that received 1600, 2900 or 5000 mg/kg. Wistar rats were grouped into 7 groups that were co-treated with L-NAME and normal saline or L-NAME and hydroethanolic leaf extract (150 and 300 mg/kg) or L-NAME and hydroethanolic root extract (150 and 300 mg/kg) or L-NAME and amlodipine (5 mg/kg) or normal saline only for 4 weeks. Treatment was carried out via the oral route while blood pressure was measured weeklyfor 4 weeks by non-invasive tail cuff method.Results:The phytochemical profile of the leaf and root extracts revealed the presence of phenols, terpenoids, flavonoids, glycosides, tannins, steroids and saponins. Both the leaf and root extracts were toxic at 5000 mg/kg with an LD50of 3807.89 mg/kg. In the fourth week of the study, only the leaf extract significantly (p less 0.01) prevented the progression of L-NAME induced hypertension; systolic and diastolic blood pressure of the group treated with L-NAME and leaf extract (300 mg/kg) were 183 ± 1 and 140 ± 1 mmHg, respectively, compared to the group that was treated with L-NAME and normal saline which produced systolic and diastolic BP values of 213 ± 3 and 172 ± 4 mmHg, respectively. The extracts, especially OIR300, exhibited diuretic effects in the second and third week of study by promoting excretion of 16 and 19 ml urine, respectively, compared to 11 and 14 ml for LN group.Conclusion:The results suggest that O. imbricatum is moderately toxic at a high dose and contains a wide range of phytochemicals which offer partial protection against the development of nitric oxide deficiency hypertension.
- Full Text:
- Date Issued: June-2018
Baseline isotopic data for Wolffia spp.: another option for tracing N-loading in freshwater systems?
- Authors: Hill, Jaclyn M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68721 , vital:29308 , https://0-doi.org.wam.seals.ac.za/10.1086/696126
- Description: δ15N values of aquatic plants can reflect anthropogenic N loading. Recent work suggests the duckweed Spirodela spp. effectively maps N loading in freshwater ecosystems, but its use may be complicated by a cyanobacterium–duckweed symbiosis that could reduce its utility in low-nutrient environments. I aimed to evaluate the potential of a 2nd duckweed species Wolffia spp., which lacks a cyanobacterial symbiosis, for use in pollution monitoring in freshwater ecosystems. I used a series of laboratory experiments to investigate δ15N equilibration rates and concentration-level effects of single-source N solutions in plant tissue over 16 d to provide baseline data for sewage-plume mapping with Wolffia spp. I also tested concentration-level effects in multisource solutions to investigate the effects of mixed-source inputs. Wolffia reflected environmental N sources with a 12- to 16-d isotopic equilibration time and showed enriched and depleted δ15N ratios for manure and KNO3 solutions, respectively, but distinguished poorly between lower concentrations of manure. Fractionations at isotopic equilibrium were opposite to expectations and decreased with increasing [N]. Wolffia showed a consistent preference for NH3 in mixed-source treatments, regardless of the proportion or concentration of NH3 or NO3– available, and a capacity for N storage, which may complicate mapping of N-loading in natural environments. Wolffia is likely to be a less useful bioindicator than the previously tested Spirodela. Future research should focus on field applications of Spirodela spp. to test its capacity for sewage-plume mapping of freshwater ecosystems in a natural environment.
- Full Text: false
- Date Issued: 2018
Baseline isotopic data for Wolffia spp.: another option for tracing N-loading in freshwater systems?
- Authors: Hill, Jaclyn M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68721 , vital:29308 , https://0-doi.org.wam.seals.ac.za/10.1086/696126
- Description: δ15N values of aquatic plants can reflect anthropogenic N loading. Recent work suggests the duckweed Spirodela spp. effectively maps N loading in freshwater ecosystems, but its use may be complicated by a cyanobacterium–duckweed symbiosis that could reduce its utility in low-nutrient environments. I aimed to evaluate the potential of a 2nd duckweed species Wolffia spp., which lacks a cyanobacterial symbiosis, for use in pollution monitoring in freshwater ecosystems. I used a series of laboratory experiments to investigate δ15N equilibration rates and concentration-level effects of single-source N solutions in plant tissue over 16 d to provide baseline data for sewage-plume mapping with Wolffia spp. I also tested concentration-level effects in multisource solutions to investigate the effects of mixed-source inputs. Wolffia reflected environmental N sources with a 12- to 16-d isotopic equilibration time and showed enriched and depleted δ15N ratios for manure and KNO3 solutions, respectively, but distinguished poorly between lower concentrations of manure. Fractionations at isotopic equilibrium were opposite to expectations and decreased with increasing [N]. Wolffia showed a consistent preference for NH3 in mixed-source treatments, regardless of the proportion or concentration of NH3 or NO3– available, and a capacity for N storage, which may complicate mapping of N-loading in natural environments. Wolffia is likely to be a less useful bioindicator than the previously tested Spirodela. Future research should focus on field applications of Spirodela spp. to test its capacity for sewage-plume mapping of freshwater ecosystems in a natural environment.
- Full Text: false
- Date Issued: 2018
Development of an LCT-Based MOOC Taxonomy
- Authors: Motara, Yusuf, M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428972 , vital:72550 , https://doi.org/10.1145/3289406.3289411
- Description: Codecademy is an example of a successful and disruptive player in the online education space. This work describes the structure, content, and experience of working through a Codecademy Pro Intensive module and compares it to the offline approach in a similar domain. Existing taxonomies are insufficiently general to explain its success, and a new taxonomy based on Legitimation Code Theory is developed to compensate. This taxonomy is arguably more meaningful and more general than those presently in use.
- Full Text:
- Date Issued: 2018
- Authors: Motara, Yusuf, M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428972 , vital:72550 , https://doi.org/10.1145/3289406.3289411
- Description: Codecademy is an example of a successful and disruptive player in the online education space. This work describes the structure, content, and experience of working through a Codecademy Pro Intensive module and compares it to the offline approach in a similar domain. Existing taxonomies are insufficiently general to explain its success, and a new taxonomy based on Legitimation Code Theory is developed to compensate. This taxonomy is arguably more meaningful and more general than those presently in use.
- Full Text:
- Date Issued: 2018
Digital Inclusion: A model for e-Infrastructure and e-Services in Developing Countries
- Terzoli, Alfredo, Siebörger, Ingrid, Tsietsi, Mosiuoa, Gumbo, Sibukelo
- Authors: Terzoli, Alfredo , Siebörger, Ingrid , Tsietsi, Mosiuoa , Gumbo, Sibukelo
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430973 , vital:72733 , https://doi.org/10.1007/978-3-319-98827-6_7
- Description: A large portion of the South African population is still not connected in a productive manner to the Internet, despite the existence of a govern-ment plan for public broadband, ‘SA Connect’. One reason for this could be the lack of an appropriate model, through which connectivity can be diffused in a meaningful way through all areas of South Africa. This paper presents the model developed over more than a decade of experimentation in real life settings in the Siyakhula Living Lab, a joint venture between the universities of Rhodes and Fort Hare, South Afri-ca. The model proposes the ‘Broadband Island’ as basic e-infrastructure unit, which clusters nearby points-of-presence hosted in schools. In each Broadband Island is located an applications integra-tion platform, TeleWeaver, which monetizes channels of access to the local community, to support the e-infrastructure while providing useful services to the population and the Government.
- Full Text:
- Date Issued: 2018
- Authors: Terzoli, Alfredo , Siebörger, Ingrid , Tsietsi, Mosiuoa , Gumbo, Sibukelo
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430973 , vital:72733 , https://doi.org/10.1007/978-3-319-98827-6_7
- Description: A large portion of the South African population is still not connected in a productive manner to the Internet, despite the existence of a govern-ment plan for public broadband, ‘SA Connect’. One reason for this could be the lack of an appropriate model, through which connectivity can be diffused in a meaningful way through all areas of South Africa. This paper presents the model developed over more than a decade of experimentation in real life settings in the Siyakhula Living Lab, a joint venture between the universities of Rhodes and Fort Hare, South Afri-ca. The model proposes the ‘Broadband Island’ as basic e-infrastructure unit, which clusters nearby points-of-presence hosted in schools. In each Broadband Island is located an applications integra-tion platform, TeleWeaver, which monetizes channels of access to the local community, to support the e-infrastructure while providing useful services to the population and the Government.
- Full Text:
- Date Issued: 2018
Genetic analysis reveals harvested Lethrinus nebulosus in the Southwest Indian Ocean comprise two cryptic species
- Healey, Amy J E, Gouws, Gavin, Fennessy, Sean T, Kuguru, Baraka, Sauer, Warwick H H, Shaw, Paul W, McKeown, Niall J
- Authors: Healey, Amy J E , Gouws, Gavin , Fennessy, Sean T , Kuguru, Baraka , Sauer, Warwick H H , Shaw, Paul W , McKeown, Niall J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124538 , vital:35626 , https://doi.10.1093/icesjms/fsx245
- Description: This study initially aimed to investigate the genetic population/stock structuring of Lethrinus nebulosus in the Southwest Indian Ocean (SWIO) to inform management practices in light of emerging evidence of overharvesting of this species throughout its distribution. Adult samples were genotyped for 14 nuclear microsatellites and by sequencing fragments of the mtDNA control region and COI gene. A salient feature of the data was the congruent cyto-nuclear partitioning of samples into two high divergent, reciprocally monophyletic groups. This indicates that despite no a priori evidence, hitherto described L. nebulosus in the SWIO comprises two cryptic species that co-occur among southern samples. This intermingling indicates that, at least in southern samples, both species are being indiscriminately harvested, which may severely compromise sustainability. Limited microsatellite differentiation was detected within both species, though there was some evidence of isolation in the Mauritian population. In contrast, mtDNA revealed a pattern consistent with chaotic genetic patchiness, likely promoted by stochastic recruitment, which may necessitate a spatial bet-hedging approach to management to satisfy fishery management and conservation goals.
- Full Text:
- Date Issued: 2018
- Authors: Healey, Amy J E , Gouws, Gavin , Fennessy, Sean T , Kuguru, Baraka , Sauer, Warwick H H , Shaw, Paul W , McKeown, Niall J
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124538 , vital:35626 , https://doi.10.1093/icesjms/fsx245
- Description: This study initially aimed to investigate the genetic population/stock structuring of Lethrinus nebulosus in the Southwest Indian Ocean (SWIO) to inform management practices in light of emerging evidence of overharvesting of this species throughout its distribution. Adult samples were genotyped for 14 nuclear microsatellites and by sequencing fragments of the mtDNA control region and COI gene. A salient feature of the data was the congruent cyto-nuclear partitioning of samples into two high divergent, reciprocally monophyletic groups. This indicates that despite no a priori evidence, hitherto described L. nebulosus in the SWIO comprises two cryptic species that co-occur among southern samples. This intermingling indicates that, at least in southern samples, both species are being indiscriminately harvested, which may severely compromise sustainability. Limited microsatellite differentiation was detected within both species, though there was some evidence of isolation in the Mauritian population. In contrast, mtDNA revealed a pattern consistent with chaotic genetic patchiness, likely promoted by stochastic recruitment, which may necessitate a spatial bet-hedging approach to management to satisfy fishery management and conservation goals.
- Full Text:
- Date Issued: 2018
Genomic analysis reveals multiple mismatches between biological and management units in yellowfin tuna (Thunnus albacares)
- Mullins, Rachel B, McKeown, Niall J, Sauer, Warwick H H, Shaw, Paul W
- Authors: Mullins, Rachel B , McKeown, Niall J , Sauer, Warwick H H , Shaw, Paul W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124549 , vital:35627 , https://doi.10.1093/icesjms/fsy102
- Description: The South African (SAF) yellowfin tuna (Thunnus albacares) fishery represents a potential example of misalignment between management units and biological processes. The SAF fishery spans an operational stock with a boundary at 20_E, either side of which fish are considered part of Atlantic or Indian Ocean regional stocks. However, the actual recruitment of fish from Atlantic and Indian Ocean spawning populations into SAF waters is unknown. To address this knowledge gap, genomic analysis (11 101 SNPs) was performed on samples from Atlantic and Indian Ocean spawning sites, including SAF sites spanning the current stock boundary. Outlier loci conferred high discriminatory power to assignment tests and revealed that all SAF fish were assigned to the Indian Ocean population and that no Atlantic Ocean fish appeared in the SAF samples. Additionally, several Indian Ocean migrants were detected at the Atlantic spawning site demonstrating asymmetric dispersal and the occurrence of a mixed-stock fishery in Atlantic waters. This study highlights both the spatial inaccuracy of current stock designations and a misunderstanding of interactions between the underlying biological units, which must be addressed in light of local and global declines of the species. Specifically, the entire SAF fishery must be managed as part of the Indian Ocean stock.
- Full Text:
- Date Issued: 2018
- Authors: Mullins, Rachel B , McKeown, Niall J , Sauer, Warwick H H , Shaw, Paul W
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124549 , vital:35627 , https://doi.10.1093/icesjms/fsy102
- Description: The South African (SAF) yellowfin tuna (Thunnus albacares) fishery represents a potential example of misalignment between management units and biological processes. The SAF fishery spans an operational stock with a boundary at 20_E, either side of which fish are considered part of Atlantic or Indian Ocean regional stocks. However, the actual recruitment of fish from Atlantic and Indian Ocean spawning populations into SAF waters is unknown. To address this knowledge gap, genomic analysis (11 101 SNPs) was performed on samples from Atlantic and Indian Ocean spawning sites, including SAF sites spanning the current stock boundary. Outlier loci conferred high discriminatory power to assignment tests and revealed that all SAF fish were assigned to the Indian Ocean population and that no Atlantic Ocean fish appeared in the SAF samples. Additionally, several Indian Ocean migrants were detected at the Atlantic spawning site demonstrating asymmetric dispersal and the occurrence of a mixed-stock fishery in Atlantic waters. This study highlights both the spatial inaccuracy of current stock designations and a misunderstanding of interactions between the underlying biological units, which must be addressed in light of local and global declines of the species. Specifically, the entire SAF fishery must be managed as part of the Indian Ocean stock.
- Full Text:
- Date Issued: 2018
Homology modeling and docking of AahII-Nanobody complexes reveal the epitope binding site on AahII scorpion toxin
- Ksouri, Ayoub, Ghedira, Kais, Abderrazek, Rahma Ben, Shankar, B A Gowri, Benkahla, Alia, Tastan Bishop, Özlem, Bouhaouala-Zahar, Balkis
- Authors: Ksouri, Ayoub , Ghedira, Kais , Abderrazek, Rahma Ben , Shankar, B A Gowri , Benkahla, Alia , Tastan Bishop, Özlem , Bouhaouala-Zahar, Balkis
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124604 , vital:35637 , https://doi.10.1016/j.bbrc.2018.01.036
- Description: Scorpion envenoming and its treatment is a public health problem in many parts of the world due to highly toxic venom polypeptides diffusing rapidly within the body of severely envenomed victims. Recently, 38 AahII-specific Nanobody sequences (Nbs) were retrieved from which the performance of NbAahII10 nanobody candidate, to neutralize the most poisonous venom compound namely AahII acting on sodium channels, was established. Herein, structural computational approach is conducted to elucidate the Nb-AahII interactions that support the biological characteristics, using Nb multiple sequence alignment (MSA) followed by modeling and molecular docking investigations (RosettaAntibody, ZDOCK software tools). Sequence and structural analysis showed two dissimilar residues of NbAahII10 CDR1 (Tyr27 and Tyr29) and an inserted polar residue Ser30 that appear to play an important role. Indeed, CDR3 region of NbAahII10 is characterized by a specific Met104 and two negatively chargedresidues Asp115 and Asp117. Complex dockings reveal that NbAahII17 and NbAahII38 share one common binding site on the surface of the AahII toxin divergent from the NbAahII10 one's. At least, a couple of NbAahII10 e AahII residue interactions (Gln38 e Asn44 and Arg62, His64, respectively) are mainly involved in the toxic AahII binding site. Altogether, this study gives valuable insights in the design and development of next generation of antivenom.
- Full Text:
- Date Issued: 2018
- Authors: Ksouri, Ayoub , Ghedira, Kais , Abderrazek, Rahma Ben , Shankar, B A Gowri , Benkahla, Alia , Tastan Bishop, Özlem , Bouhaouala-Zahar, Balkis
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124604 , vital:35637 , https://doi.10.1016/j.bbrc.2018.01.036
- Description: Scorpion envenoming and its treatment is a public health problem in many parts of the world due to highly toxic venom polypeptides diffusing rapidly within the body of severely envenomed victims. Recently, 38 AahII-specific Nanobody sequences (Nbs) were retrieved from which the performance of NbAahII10 nanobody candidate, to neutralize the most poisonous venom compound namely AahII acting on sodium channels, was established. Herein, structural computational approach is conducted to elucidate the Nb-AahII interactions that support the biological characteristics, using Nb multiple sequence alignment (MSA) followed by modeling and molecular docking investigations (RosettaAntibody, ZDOCK software tools). Sequence and structural analysis showed two dissimilar residues of NbAahII10 CDR1 (Tyr27 and Tyr29) and an inserted polar residue Ser30 that appear to play an important role. Indeed, CDR3 region of NbAahII10 is characterized by a specific Met104 and two negatively chargedresidues Asp115 and Asp117. Complex dockings reveal that NbAahII17 and NbAahII38 share one common binding site on the surface of the AahII toxin divergent from the NbAahII10 one's. At least, a couple of NbAahII10 e AahII residue interactions (Gln38 e Asn44 and Arg62, His64, respectively) are mainly involved in the toxic AahII binding site. Altogether, this study gives valuable insights in the design and development of next generation of antivenom.
- Full Text:
- Date Issued: 2018