Import licensing regulation within the WTO: a case study of the dispute between Zimbabwe and South Africa over the Control of Goods (Open General Import Licence) Notice of 2016 (Statutory Instrument 64)
- Kamunjoma, Charles https://orcid.org/0000-0002-1930-4341
- Authors: Kamunjoma, Charles https://orcid.org/0000-0002-1930-4341
- Date: 2018
- Subjects: Import quotas , Customs unions , Africa, Southern -- Economic integration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27854 , vital:70097
- Description: Over the years, Zimbabwe has arbitrarily enforced trade restrictive measures including mandatory inspections on certain products, duty increases, surtaxes and import permits on basic products such as cooking oil. The measures have been allegedly targeting goods from South Africa. Amongst the most recent restrictive measures imposed by Zimbabwe is SI 64 of 2016 that now operates as SI 122 of 2017. In response to SI 64, for the first time, South Africa threatened retaliation. As a result, there is visible trade tension between Zimbabwe and South Africa. With the absence of an effective dispute settlement mechanism within SADC, or most African Regional Economic Communities RECs for that matter, a WTO approach to the issue will provide valuable insights on how else South Africa (and other African countries) can deal with cross-border trade problems such as the ones posed by SI 64. , Thesis (LLM) -- Faculty of Law, 2018
- Full Text:
- Date Issued: 2018
- Authors: Kamunjoma, Charles https://orcid.org/0000-0002-1930-4341
- Date: 2018
- Subjects: Import quotas , Customs unions , Africa, Southern -- Economic integration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27854 , vital:70097
- Description: Over the years, Zimbabwe has arbitrarily enforced trade restrictive measures including mandatory inspections on certain products, duty increases, surtaxes and import permits on basic products such as cooking oil. The measures have been allegedly targeting goods from South Africa. Amongst the most recent restrictive measures imposed by Zimbabwe is SI 64 of 2016 that now operates as SI 122 of 2017. In response to SI 64, for the first time, South Africa threatened retaliation. As a result, there is visible trade tension between Zimbabwe and South Africa. With the absence of an effective dispute settlement mechanism within SADC, or most African Regional Economic Communities RECs for that matter, a WTO approach to the issue will provide valuable insights on how else South Africa (and other African countries) can deal with cross-border trade problems such as the ones posed by SI 64. , Thesis (LLM) -- Faculty of Law, 2018
- Full Text:
- Date Issued: 2018
Improved Photophysical and Photochemical Properties of Thiopheneethoxy Substituted Metallophthalocyanines on Immobilization onto Gold‐speckled Silica Nanoparticles
- Dube, Edith, Oluwole, David O, Nyokong, Tebello
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018
Improving internal control systems in the public sector: the Eastern Cape department of Sport, Recreation, Arts and Culture
- Authors: Mtshotshisa, Mongezi
- Date: 2018
- Subjects: Finance, Public -- South Africa -- Eastern Cape , Financial management Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10948/32997 , vital:32489
- Description: It is important to note that control weaknesses are of two types. Firstly, design weaknesses are where controls are inadequately designed. Secondly, implementation weaknesses are where controls may be designed very well, but implementation by officials may be inadequate or irregular. Hence this study is about improving internal control systems in the public sector. The objective of this study is to determine how the Department of Sport, Recreation, Arts, and Culture can move from an unqualified audit report to a clean audit report. The researcher found that internal controls are very important in the operations of the department as a whole, especial in financial governance. The internal controls play an integral part in the organisation because all processes need controls as a tool to mitigate against the risks. In order for the department to prevent the emphasis of matter on audit reports or to achieve clean audit report, it must strengthen its internal controls. Although this study did not cover the issues of pre-determined objectives, implementation of internal controls is necessary for the improvement of reporting on performance information. The study concluded that the Department of Sport, Recreation, Arts, and Culture complies with international best practice pertaining to internal controls and financial reporting. The department has a great opportunity to obtain a clean audit report. It also has the potential to increase the effectiveness and efficiency of its internal controls by strengthening the functioning of the internal control committee, risk management committee as well as the finance committee (In Year Monitoring). The executive authority and senior management of the department are the people who should enforce the implementation of internal controls through the use of the internal control function of the department, although the audit committee assists in ensuring the effectiveness of these internal controls.
- Full Text:
- Date Issued: 2018
- Authors: Mtshotshisa, Mongezi
- Date: 2018
- Subjects: Finance, Public -- South Africa -- Eastern Cape , Financial management Public administration -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: http://hdl.handle.net/10948/32997 , vital:32489
- Description: It is important to note that control weaknesses are of two types. Firstly, design weaknesses are where controls are inadequately designed. Secondly, implementation weaknesses are where controls may be designed very well, but implementation by officials may be inadequate or irregular. Hence this study is about improving internal control systems in the public sector. The objective of this study is to determine how the Department of Sport, Recreation, Arts, and Culture can move from an unqualified audit report to a clean audit report. The researcher found that internal controls are very important in the operations of the department as a whole, especial in financial governance. The internal controls play an integral part in the organisation because all processes need controls as a tool to mitigate against the risks. In order for the department to prevent the emphasis of matter on audit reports or to achieve clean audit report, it must strengthen its internal controls. Although this study did not cover the issues of pre-determined objectives, implementation of internal controls is necessary for the improvement of reporting on performance information. The study concluded that the Department of Sport, Recreation, Arts, and Culture complies with international best practice pertaining to internal controls and financial reporting. The department has a great opportunity to obtain a clean audit report. It also has the potential to increase the effectiveness and efficiency of its internal controls by strengthening the functioning of the internal control committee, risk management committee as well as the finance committee (In Year Monitoring). The executive authority and senior management of the department are the people who should enforce the implementation of internal controls through the use of the internal control function of the department, although the audit committee assists in ensuring the effectiveness of these internal controls.
- Full Text:
- Date Issued: 2018
Improving leadership development in the Eastern Cape Treasury: a succession planning and leadership development study
- Authors: Zuzile, Zikhona Siviwe
- Date: 2018
- Subjects: Development leadership -- South Africa -- Eastern Cape Executive succession -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/19575 , vital:28895
- Description: Leadership development is very important in business and much is often said about ‘growing’ leaders in business organisations. Leadership development cannot be achieved in one training course or programme, but should rather be an everyday practice of existing leaders. Leader development concentrates on individual leader development, enrichment or attainment of within-person competence while leadership development concentrates on relational development. This paper addresses and outlines how an all-inclusive method to leadership development and succession planning is needed for the employees of the Eastern Cape Treasury. It also looks at the willingness of the existing leadership in government to coach and mentor the youth of today to take on a leadership role when the current leaders exit the market. The head office in Bhisho for the Eastern Cape Treasury has 390 employees and in total, when combined with district offices around the Eastern Cape, there are 454. The questionnaire was sent out to 80 employees and 55 of those were filled and returned to the researcher. The targeted employees were those in the following positions: Administrative Officer, Assistant Director, Deputy Director, Director and Chief Director. The empirical results though showed that Autocratic Leadership and Satisfaction with Compensation Package had no correlation with Leadership development, whereas Organisational Culture, Senior Management Support and Participative Leadership Style showed positive correlation with Leadership development success. Implementing the recommendations might help with improving leadership development in the Provincial Treasury.
- Full Text:
- Date Issued: 2018
- Authors: Zuzile, Zikhona Siviwe
- Date: 2018
- Subjects: Development leadership -- South Africa -- Eastern Cape Executive succession -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/19575 , vital:28895
- Description: Leadership development is very important in business and much is often said about ‘growing’ leaders in business organisations. Leadership development cannot be achieved in one training course or programme, but should rather be an everyday practice of existing leaders. Leader development concentrates on individual leader development, enrichment or attainment of within-person competence while leadership development concentrates on relational development. This paper addresses and outlines how an all-inclusive method to leadership development and succession planning is needed for the employees of the Eastern Cape Treasury. It also looks at the willingness of the existing leadership in government to coach and mentor the youth of today to take on a leadership role when the current leaders exit the market. The head office in Bhisho for the Eastern Cape Treasury has 390 employees and in total, when combined with district offices around the Eastern Cape, there are 454. The questionnaire was sent out to 80 employees and 55 of those were filled and returned to the researcher. The targeted employees were those in the following positions: Administrative Officer, Assistant Director, Deputy Director, Director and Chief Director. The empirical results though showed that Autocratic Leadership and Satisfaction with Compensation Package had no correlation with Leadership development, whereas Organisational Culture, Senior Management Support and Participative Leadership Style showed positive correlation with Leadership development success. Implementing the recommendations might help with improving leadership development in the Provincial Treasury.
- Full Text:
- Date Issued: 2018
Improving tax compliance of small businesses through effective communication
- Authors: Nontshinga, Chuma Zintle
- Date: 2018
- Subjects: Small business -- Taxation , Taxpayer compliance -- Communication Taxation Communication in law
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22902 , vital:30127
- Description: The small business sector is growing rapidly worldwide. It has been noted that the small business sector plays a vital role in the social as well as the economic development of the country. However this has brought about some challenges with regards to tax compliance. Within the Eastern Cape there is a vast difference in customer base, with some taxpayers being illiterate the non-compliance challenge becomes rather a critical focus. The limited tax knowledge within the small business sector as well as the complex tax language has contributed to small businesses being tax non-compliant. It is for this reason that this study became apparent. The primary objective of this study is to identify the variables to improve tax compliance for the small business segment by investigating the determinants of effective communication. More specifically this study will investigate the influence of communication channels, communication frequency, Information Technology Communication and tax education on tax compliance. To achieve the primary objective of this study, secondary and primary research was undertaken. The positivistic research methodology was adopted as relationships were tested as well as it emphasised the quantification of the data collected and analysed. Four determinants of effective communication (Communication Channels, Communication Frequency, Information Technology Communication and Tax Education) served as the independent variables, while Perceived Success of Tax Compliance served as the dependent variable. The majority of respondents were females with a 61% representation and males represented 39% of the responds. Most respondents were between the ages of 36 and 45 years, the age group profile depicts the diversity of the maturity levels within the respondents. From the descriptive statistics it was observed that the majority of the respondents agreed that their businesses were tax compliant. For the independent variables, the reported average mean values ranged from 3.03 to 3.97 with the highest mean value being reported for the variable of Tax Education and the lowest score reported for Communication Frequency. In accordance with the literature review and the findings from the empirical data obtained and analysed in this study, it can be concluded that tax compliance is a function of many variables. The study has revealed that the determinants of effective communication that were identified as independent variables have an impact on the perceived success of tax compliance. In other words, an increase in the independent variable will lead to an increase in the level of tax compliance.
- Full Text:
- Date Issued: 2018
- Authors: Nontshinga, Chuma Zintle
- Date: 2018
- Subjects: Small business -- Taxation , Taxpayer compliance -- Communication Taxation Communication in law
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22902 , vital:30127
- Description: The small business sector is growing rapidly worldwide. It has been noted that the small business sector plays a vital role in the social as well as the economic development of the country. However this has brought about some challenges with regards to tax compliance. Within the Eastern Cape there is a vast difference in customer base, with some taxpayers being illiterate the non-compliance challenge becomes rather a critical focus. The limited tax knowledge within the small business sector as well as the complex tax language has contributed to small businesses being tax non-compliant. It is for this reason that this study became apparent. The primary objective of this study is to identify the variables to improve tax compliance for the small business segment by investigating the determinants of effective communication. More specifically this study will investigate the influence of communication channels, communication frequency, Information Technology Communication and tax education on tax compliance. To achieve the primary objective of this study, secondary and primary research was undertaken. The positivistic research methodology was adopted as relationships were tested as well as it emphasised the quantification of the data collected and analysed. Four determinants of effective communication (Communication Channels, Communication Frequency, Information Technology Communication and Tax Education) served as the independent variables, while Perceived Success of Tax Compliance served as the dependent variable. The majority of respondents were females with a 61% representation and males represented 39% of the responds. Most respondents were between the ages of 36 and 45 years, the age group profile depicts the diversity of the maturity levels within the respondents. From the descriptive statistics it was observed that the majority of the respondents agreed that their businesses were tax compliant. For the independent variables, the reported average mean values ranged from 3.03 to 3.97 with the highest mean value being reported for the variable of Tax Education and the lowest score reported for Communication Frequency. In accordance with the literature review and the findings from the empirical data obtained and analysed in this study, it can be concluded that tax compliance is a function of many variables. The study has revealed that the determinants of effective communication that were identified as independent variables have an impact on the perceived success of tax compliance. In other words, an increase in the independent variable will lead to an increase in the level of tax compliance.
- Full Text:
- Date Issued: 2018
Improving the exhaust pigment dyeing of cotton garments
- Authors: Harilal, Shantha
- Date: 2018
- Subjects: Dyes and dyeing -- Textile fibers , Dyes and dyeing -- Chemistry Textile fabrics -- Coloring Textile fabrics Cotton -- Coloring
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22231 , vital:29895
- Description: Due to the rapid changes in fashion trends, garment dyeing is gaining popularity because of its quick response time and reduced costs, especially when dyeing with pigments. However, a drawback of pigment dyeing of cotton garments is the problem of unlevel dyeing and poor wet fastness, together with the high amount of staining of the dyeing equipment. This research has focused on investigating the effects of varying dyeing parameters on the colour strength and fastness of exhaust pigment dyed cotton garments, with the ultimate aim to improve colour strength, wet rub fastness and wash fastness; as well as try to reduce the amount of staining of the equipment, and in so doing reducing production and effluent treatment costs. The research was undertaken at a textile company, Spectrum Textiles (Pty) Ltd, which has been experiencing problems with poor wet fastness, unlevel dyeing and high staining of equipment for both knitted and woven cotton garments. Trials on knitted and woven garments were carried out in which the effects of the concentrations of the cationising agent, pigment and binder/fixer, on colour strength and dye fastness were investigated, as was also the effects of temperature, pH, material-to-liquor ratio and process route. The dyed fabrics were analysed in terms of colour strength, wash fastness and wet and dry rub fastness. It was found that, in general, increasing the amount of cationising agent, pigment, binder/fixer, pH, temperature and material-to-liquor ratio decreased the colour strength (K/S), with applying the binder/fixer prior to pigmenting mostly producing a higher K/S than when applying the binder/fixer after pigmenting. Furthermore, the use of a fixer achieved higher K/S values than when the binder was used. By the selection of the correct chemical levels and dyeing conditions, level pigment dyeing of cotton garments, with high colour strength, was achieved with Grey Scale ratings of 4 or higher for all the fastness criteria. A single optimum dyeing combination, which produced a high K/S and a Grey Scale rating of 4 or higher for wash fastness and wet and dry rub fastness, was derived.
- Full Text:
- Date Issued: 2018
- Authors: Harilal, Shantha
- Date: 2018
- Subjects: Dyes and dyeing -- Textile fibers , Dyes and dyeing -- Chemistry Textile fabrics -- Coloring Textile fabrics Cotton -- Coloring
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/22231 , vital:29895
- Description: Due to the rapid changes in fashion trends, garment dyeing is gaining popularity because of its quick response time and reduced costs, especially when dyeing with pigments. However, a drawback of pigment dyeing of cotton garments is the problem of unlevel dyeing and poor wet fastness, together with the high amount of staining of the dyeing equipment. This research has focused on investigating the effects of varying dyeing parameters on the colour strength and fastness of exhaust pigment dyed cotton garments, with the ultimate aim to improve colour strength, wet rub fastness and wash fastness; as well as try to reduce the amount of staining of the equipment, and in so doing reducing production and effluent treatment costs. The research was undertaken at a textile company, Spectrum Textiles (Pty) Ltd, which has been experiencing problems with poor wet fastness, unlevel dyeing and high staining of equipment for both knitted and woven cotton garments. Trials on knitted and woven garments were carried out in which the effects of the concentrations of the cationising agent, pigment and binder/fixer, on colour strength and dye fastness were investigated, as was also the effects of temperature, pH, material-to-liquor ratio and process route. The dyed fabrics were analysed in terms of colour strength, wash fastness and wet and dry rub fastness. It was found that, in general, increasing the amount of cationising agent, pigment, binder/fixer, pH, temperature and material-to-liquor ratio decreased the colour strength (K/S), with applying the binder/fixer prior to pigmenting mostly producing a higher K/S than when applying the binder/fixer after pigmenting. Furthermore, the use of a fixer achieved higher K/S values than when the binder was used. By the selection of the correct chemical levels and dyeing conditions, level pigment dyeing of cotton garments, with high colour strength, was achieved with Grey Scale ratings of 4 or higher for all the fastness criteria. A single optimum dyeing combination, which produced a high K/S and a Grey Scale rating of 4 or higher for wash fastness and wet and dry rub fastness, was derived.
- Full Text:
- Date Issued: 2018
Improving the implementation and sustainability of corporate performance management at Amatola Water Board
- Authors: Ntungwana, Sabelo
- Date: 2018
- Subjects: Organizational effectiveness , Organizational effectiveness -- Measurement Performance -- Management Performance -- Measurement
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/33736 , vital:33012
- Description: In the last century, researchers have studied how performance management systems could be applied effectively to achieve both financial and non-financial performance. This approach was a direct response to the need for strategic measurement systems to measure the performance of the organisation. As a results, various approaches were developed. And Amatola Water Board opted to adopt the Balanced Scorecard as its strategic measurement system. It contains outcome measures and the performance drivers of outcomes, linked together in connectedness relationships, and thus aims to be a proactive control system. Furthermore, the balanced scorecard is developed for use not only as a strategic measurement system but also as a strategic control system. Its purpose enables the departmental and personal goals to be aligned to the organisational strategy. The purpose of this research study was to first examine the extent to which there is a connectedness relationship between strategic performance and business performance. Secondly, the research study examined the extent to which the strategy is understood by all in the organisation. Thirdly, the study also examined the extent to which the performance management system is consistently applied. Finally, the study examined the extent to which performance is recognised and rewarded. Lastly, the research study discusses the empirical results and suggests some improvements to the performance measurement and management system. The researcher chose a quantitative approach to conduct the study. The quantitative approach was influenced by the positivistic research paradigm. A simple random sampling technique was used due to its probability that each unit in the population has an equal chance of being included in the sample. And a questionnaire was used as a data collection instrument. The instrument was anchored to a five (5) point Likert scale the Likert scale required the respondents to indicate their level of agreement with the statement. The statements ranged from strongly disagree to strongly agree. And the data collection instrument consisted of Thirty Five (35) questions. Regarding the pilot study, it was however not conducted for this research. The researcher acknowledged that a pilot study helps the researcher to determine how the questions are interpreted and understood by the respondents, but also indicated that it is only due to limited resources that the researcher omitted to conduct a pilot study. One Hundred and Thirty (130) questionnaires were distributed and one hundred and twenty seven (127) were returned achieving a response rate of ninety six (96) percent. And both Statistical® and SPSS® programmes were utilised for extraction of data for recognised reliability and validity. The research study revealed that Amatola Water has a performance measurement and management policy and it is being implemented. However, the study also revealed that communication and involvement is limited to management and lower level employees are not involved in the process from the beginning. The study showed evidence of lack of training for line management on how to properly execute and administer the performance measurement and management system effectively and successfully. And the analysis indicates lack of understanding of the contents of the shareholder’s compact and organisational strategy by lower level employees. Finally, the researcher made recommendations regarding the improvements in the implementation of the performance measurement and management system. And more recommendations are made regarding the participation of lower level employees in strategic direction and performance of the organization.
- Full Text:
- Date Issued: 2018
- Authors: Ntungwana, Sabelo
- Date: 2018
- Subjects: Organizational effectiveness , Organizational effectiveness -- Measurement Performance -- Management Performance -- Measurement
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/33736 , vital:33012
- Description: In the last century, researchers have studied how performance management systems could be applied effectively to achieve both financial and non-financial performance. This approach was a direct response to the need for strategic measurement systems to measure the performance of the organisation. As a results, various approaches were developed. And Amatola Water Board opted to adopt the Balanced Scorecard as its strategic measurement system. It contains outcome measures and the performance drivers of outcomes, linked together in connectedness relationships, and thus aims to be a proactive control system. Furthermore, the balanced scorecard is developed for use not only as a strategic measurement system but also as a strategic control system. Its purpose enables the departmental and personal goals to be aligned to the organisational strategy. The purpose of this research study was to first examine the extent to which there is a connectedness relationship between strategic performance and business performance. Secondly, the research study examined the extent to which the strategy is understood by all in the organisation. Thirdly, the study also examined the extent to which the performance management system is consistently applied. Finally, the study examined the extent to which performance is recognised and rewarded. Lastly, the research study discusses the empirical results and suggests some improvements to the performance measurement and management system. The researcher chose a quantitative approach to conduct the study. The quantitative approach was influenced by the positivistic research paradigm. A simple random sampling technique was used due to its probability that each unit in the population has an equal chance of being included in the sample. And a questionnaire was used as a data collection instrument. The instrument was anchored to a five (5) point Likert scale the Likert scale required the respondents to indicate their level of agreement with the statement. The statements ranged from strongly disagree to strongly agree. And the data collection instrument consisted of Thirty Five (35) questions. Regarding the pilot study, it was however not conducted for this research. The researcher acknowledged that a pilot study helps the researcher to determine how the questions are interpreted and understood by the respondents, but also indicated that it is only due to limited resources that the researcher omitted to conduct a pilot study. One Hundred and Thirty (130) questionnaires were distributed and one hundred and twenty seven (127) were returned achieving a response rate of ninety six (96) percent. And both Statistical® and SPSS® programmes were utilised for extraction of data for recognised reliability and validity. The research study revealed that Amatola Water has a performance measurement and management policy and it is being implemented. However, the study also revealed that communication and involvement is limited to management and lower level employees are not involved in the process from the beginning. The study showed evidence of lack of training for line management on how to properly execute and administer the performance measurement and management system effectively and successfully. And the analysis indicates lack of understanding of the contents of the shareholder’s compact and organisational strategy by lower level employees. Finally, the researcher made recommendations regarding the improvements in the implementation of the performance measurement and management system. And more recommendations are made regarding the participation of lower level employees in strategic direction and performance of the organization.
- Full Text:
- Date Issued: 2018
Improving understanding of the ecology of Indo-pacific bottlenose dolphins (tursiops aduncus) in Algoa Bay, South Africa
- Shaanika, Titus Mwiitantandje
- Authors: Shaanika, Titus Mwiitantandje
- Date: 2018
- Subjects: Bottlenose dolphin -- South Africa -- Port Elizabeth , Bottlenose dolphin -- Ecology -- South Africa -- Port Elizabeth Dolphins -- Ecology -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/34788 , vital:33451
- Description: Site fidelity and spatial distribution of Indo-Pacific bottlenose dolphins (Tursiops aduncus) were assesed using mark-recapture from opportunistic photographs collected between June 2008-May 2011 in Algoa Bay, South Africa. Over 10 000 photographs were collected, and assessed, resulting in 2472 photographs being catalogued and analysed. In total, 2002 individual dolphins were photographically identified. The discovery curve does not reach a plateau, indicating a large, open population, as a result, the re-sighting rate over the study period was low. 178 (8.9%) animals were re-sighted, and 32 animals these were seen three times or more. The individual which was re-sighted most often was sighted five times. The residency index averaged 0.05 and reached a maximum at 0.25. 41% of the data were collected in 2009, which skewed the identifications per unit effort (IDsPUE) across years (Kruskal-Wallis Anova, KW= 11.59 n=60, p= 0.009) and seasons (KW= 17.47, n= 60, p=0.007). Due to the relatively higher data collection in 2009, identifications across years (KW=13.29, n=60, P= 0.004) and across seasons (KW=17.81 n=60, P=0.007) also differed significantly. In contrast, there was no significant difference is re-sighting across years (KW = 6.9, n=56, p= 0.8) and seasons (KW=12.26, n=56, p=0.6). The association between the 32 individuals seen three times or more was measured using the Half Weight Index, the index ranged from 0 to 1. A dendrogram revealed two social clusters consisting of 23 and 8 animals each, with one individual having no associations. Xenobalanus was recorded on all but five surveys over the study period. Xenobalanus occurrence did not significantly differ across years (KW=1.49, n=42, p=0.68) and seasons (KW= 6.59, n=43, p=0.36). Dolphins were mostly sighted in depths of <15 metres all around the bay. Travelling (36%) behaviour was the most recorded, followed by feeding (29 %), socialising (15%), milling (11 %), Slow travel (6%), resting (2%) and fast travelling (1%). Other than milling the spatial distribution of all behaviours were similar to the general spatial distribution of sightings. The project provides information that can be used for further research and conservation management of T. aduncus. Photographs used in this project were opportunistically collected, which has resulted in the underestimation of photo-identified individuals and consequently results of this project.
- Full Text:
- Date Issued: 2018
- Authors: Shaanika, Titus Mwiitantandje
- Date: 2018
- Subjects: Bottlenose dolphin -- South Africa -- Port Elizabeth , Bottlenose dolphin -- Ecology -- South Africa -- Port Elizabeth Dolphins -- Ecology -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/34788 , vital:33451
- Description: Site fidelity and spatial distribution of Indo-Pacific bottlenose dolphins (Tursiops aduncus) were assesed using mark-recapture from opportunistic photographs collected between June 2008-May 2011 in Algoa Bay, South Africa. Over 10 000 photographs were collected, and assessed, resulting in 2472 photographs being catalogued and analysed. In total, 2002 individual dolphins were photographically identified. The discovery curve does not reach a plateau, indicating a large, open population, as a result, the re-sighting rate over the study period was low. 178 (8.9%) animals were re-sighted, and 32 animals these were seen three times or more. The individual which was re-sighted most often was sighted five times. The residency index averaged 0.05 and reached a maximum at 0.25. 41% of the data were collected in 2009, which skewed the identifications per unit effort (IDsPUE) across years (Kruskal-Wallis Anova, KW= 11.59 n=60, p= 0.009) and seasons (KW= 17.47, n= 60, p=0.007). Due to the relatively higher data collection in 2009, identifications across years (KW=13.29, n=60, P= 0.004) and across seasons (KW=17.81 n=60, P=0.007) also differed significantly. In contrast, there was no significant difference is re-sighting across years (KW = 6.9, n=56, p= 0.8) and seasons (KW=12.26, n=56, p=0.6). The association between the 32 individuals seen three times or more was measured using the Half Weight Index, the index ranged from 0 to 1. A dendrogram revealed two social clusters consisting of 23 and 8 animals each, with one individual having no associations. Xenobalanus was recorded on all but five surveys over the study period. Xenobalanus occurrence did not significantly differ across years (KW=1.49, n=42, p=0.68) and seasons (KW= 6.59, n=43, p=0.36). Dolphins were mostly sighted in depths of <15 metres all around the bay. Travelling (36%) behaviour was the most recorded, followed by feeding (29 %), socialising (15%), milling (11 %), Slow travel (6%), resting (2%) and fast travelling (1%). Other than milling the spatial distribution of all behaviours were similar to the general spatial distribution of sightings. The project provides information that can be used for further research and conservation management of T. aduncus. Photographs used in this project were opportunistically collected, which has resulted in the underestimation of photo-identified individuals and consequently results of this project.
- Full Text:
- Date Issued: 2018
In silico analysis, isolation and kinetic characterisation of red algae (Rhodophyta) catalases
- Authors: Nodangala, Sinovuyo
- Date: 2018
- Subjects: Red algae Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14626 , vital:40024
- Description: Catalase (EC: 1.11.1.6) is produced by almost all aerobic organism ranging from bacteria to human and is an essential antioxidant enzyme that catalyses the conversion of hydrogen peroxide to water and molecular oxygen, therefore neutralising hydrogen peroxide toxicity. The present study aimed to purify and characterise catalase from Pachymenia orbitosa, a marine red algae found in the Algoa Bay region of South Africa. Bioinformatics analysis was performed to confirm the presence of a catalase gene in the red algae genome. In silico analysis of the Chondrus crispus genome was performed to predict the functional and structural characterisation of the protein encoded by the gene. The Pachymenia orbitosa catalase enzyme was purified to homogeneity using 60% ammonium sulphate precipitation and Sephacryl S-200 gel filtration chromatography. InterProScan confirmed that the Chondrus crispus genome encodes a catalase protein, which is from the mono-functional and heme-dependent catalase-like superfamily. The purified Pachymenia orbitosa catalase enzyme displayed a specific activity of 23 000 units per mg of protein with a 14.94% recovery and 222.91 fold purification. Sodium dodecyl sulphatepolyacrylamide gel electrophoresis indicated a single band, with a molecular weight of around 50kDa. The catalase enzyme exhibited a maximum activity at pH 7 and a temperature of 30℃. It was stable up to 40℃ and rapidly denatured at temperatures above this. The Km and Vmax values for the purified catalase, using hydrogen peroxide as a substrate, were determined from the Lineweaver-Burk plot to be 22.22mM and 1.11x10-4mM.min-1 , respectively, while from the Hanes-Woolf plot, to be 23.4mM and 1.17x10-4mM.min-1 , respectively. The Heme catalase inhibitor (ferricyanide) inhibited the enzyme activity markedly, while sodium chloride and citric acid had only a slight inhibitory effect. Copper sulphate showed a slight stimulatory effect. The physiochemical properties suggest a good application potential in both the pharmaceutical and food industries
- Full Text:
- Date Issued: 2018
- Authors: Nodangala, Sinovuyo
- Date: 2018
- Subjects: Red algae Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14626 , vital:40024
- Description: Catalase (EC: 1.11.1.6) is produced by almost all aerobic organism ranging from bacteria to human and is an essential antioxidant enzyme that catalyses the conversion of hydrogen peroxide to water and molecular oxygen, therefore neutralising hydrogen peroxide toxicity. The present study aimed to purify and characterise catalase from Pachymenia orbitosa, a marine red algae found in the Algoa Bay region of South Africa. Bioinformatics analysis was performed to confirm the presence of a catalase gene in the red algae genome. In silico analysis of the Chondrus crispus genome was performed to predict the functional and structural characterisation of the protein encoded by the gene. The Pachymenia orbitosa catalase enzyme was purified to homogeneity using 60% ammonium sulphate precipitation and Sephacryl S-200 gel filtration chromatography. InterProScan confirmed that the Chondrus crispus genome encodes a catalase protein, which is from the mono-functional and heme-dependent catalase-like superfamily. The purified Pachymenia orbitosa catalase enzyme displayed a specific activity of 23 000 units per mg of protein with a 14.94% recovery and 222.91 fold purification. Sodium dodecyl sulphatepolyacrylamide gel electrophoresis indicated a single band, with a molecular weight of around 50kDa. The catalase enzyme exhibited a maximum activity at pH 7 and a temperature of 30℃. It was stable up to 40℃ and rapidly denatured at temperatures above this. The Km and Vmax values for the purified catalase, using hydrogen peroxide as a substrate, were determined from the Lineweaver-Burk plot to be 22.22mM and 1.11x10-4mM.min-1 , respectively, while from the Hanes-Woolf plot, to be 23.4mM and 1.17x10-4mM.min-1 , respectively. The Heme catalase inhibitor (ferricyanide) inhibited the enzyme activity markedly, while sodium chloride and citric acid had only a slight inhibitory effect. Copper sulphate showed a slight stimulatory effect. The physiochemical properties suggest a good application potential in both the pharmaceutical and food industries
- Full Text:
- Date Issued: 2018
In silico characterization of plasmodial transketolases as potential malaria drug target
- Authors: Boateng, Rita Afriyie
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63540 , vital:28433
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
- Authors: Boateng, Rita Afriyie
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63540 , vital:28433
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
In silico study of Plasmodium 1-deoxy-dxylulose 5-phosphate reductoisomerase (DXR) for identification of novel inhibitors from SANCDB
- Authors: Diallo, Bakary N'tji
- Date: 2018
- Subjects: Plasmodium 1-deoxy-dxylulose 5-phosphate reductoisomerase , Isoprenoids , Plasmodium , Antimalarials , Malaria -- Chemotherapy , Molecules -- Models , Molecular dynamics , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64012 , vital:28523
- Description: Malaria remains a major health concern with a complex parasite constantly developing resistance to the different drugs introduced to treat it, threatening the efficacy of the current ACT treatment recommended by WHO (World Health Organization). Different antimalarial compounds with different mechanisms of action are ideal as this decreases chances of resistance occurring. Inhibiting DXR and consequently the MEP pathway is a good strategy to find a new antimalarial with a novel mode of action. From literature, all the enzymes of the MEP pathway have also been shown to be indispensable for the synthesis of isoprenoids. They have been validated as drug targets and the X-ray structure of each of the enzymes has been solved. DXR is a protein which catalyses the second step of the MEP pathway. There are currently 255 DXR inhibitors in the Binding Database (accessed November 2017) generally based on the fosmidomycin structural scaffold and thus often showing poor drug likeness properties. This study aims to research new DXR inhibitors using in silico techniques. We analysed the protein sequence and built 3D models in close and open conformations for the different Plasmodium sequences. Then SANCDB compounds were screened to identify new potential DXR inhibitors with new chemical scaffolds. Finally, the identified hits were submitted to molecular dynamics studies, preceded by a parameterization of the manganese atom in the protein active site.
- Full Text:
- Date Issued: 2018
- Authors: Diallo, Bakary N'tji
- Date: 2018
- Subjects: Plasmodium 1-deoxy-dxylulose 5-phosphate reductoisomerase , Isoprenoids , Plasmodium , Antimalarials , Malaria -- Chemotherapy , Molecules -- Models , Molecular dynamics , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64012 , vital:28523
- Description: Malaria remains a major health concern with a complex parasite constantly developing resistance to the different drugs introduced to treat it, threatening the efficacy of the current ACT treatment recommended by WHO (World Health Organization). Different antimalarial compounds with different mechanisms of action are ideal as this decreases chances of resistance occurring. Inhibiting DXR and consequently the MEP pathway is a good strategy to find a new antimalarial with a novel mode of action. From literature, all the enzymes of the MEP pathway have also been shown to be indispensable for the synthesis of isoprenoids. They have been validated as drug targets and the X-ray structure of each of the enzymes has been solved. DXR is a protein which catalyses the second step of the MEP pathway. There are currently 255 DXR inhibitors in the Binding Database (accessed November 2017) generally based on the fosmidomycin structural scaffold and thus often showing poor drug likeness properties. This study aims to research new DXR inhibitors using in silico techniques. We analysed the protein sequence and built 3D models in close and open conformations for the different Plasmodium sequences. Then SANCDB compounds were screened to identify new potential DXR inhibitors with new chemical scaffolds. Finally, the identified hits were submitted to molecular dynamics studies, preceded by a parameterization of the manganese atom in the protein active site.
- Full Text:
- Date Issued: 2018
In vitro analysis of putative cancer stem cell populations and chemosensitivity in the SW480 and SW620 colon cancer metastasis model:
- Slater, Cindy, de la Mare, Jo-Anne, Edkins, Adrienne L
- Authors: Slater, Cindy , de la Mare, Jo-Anne , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164401 , vital:41115 , DOI: 10.3892/ol.2018.8431
- Description: The cancer stem cell (CSC) theory implicates a small subpopulation of cells with stem like properties, which is responsible for tumour initiation, development and metastasis. The unique biological and functional characteristics of CSCs, widely associated with treatment resistance, indicate an association between metastasis and stemness. It was hypothesised that metastatic cell lines may be enriched in CSCs and that this would correlate with a more resistant tumour. In the present study, the SW480 and SW620 paired cell lines derived from a colon adenocarcinoma and its lymph node metastasis, respectively were compared as an in vitro model of cancer progression. Their chemosensitivity and CSC properties were investigated. A range of in vitro assays were performed, including the side population assay, ALDEFLUOR assay, tumoursphere assay and assessment of CSC associated surface phenotypes.
- Full Text:
- Date Issued: 2018
- Authors: Slater, Cindy , de la Mare, Jo-Anne , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164401 , vital:41115 , DOI: 10.3892/ol.2018.8431
- Description: The cancer stem cell (CSC) theory implicates a small subpopulation of cells with stem like properties, which is responsible for tumour initiation, development and metastasis. The unique biological and functional characteristics of CSCs, widely associated with treatment resistance, indicate an association between metastasis and stemness. It was hypothesised that metastatic cell lines may be enriched in CSCs and that this would correlate with a more resistant tumour. In the present study, the SW480 and SW620 paired cell lines derived from a colon adenocarcinoma and its lymph node metastasis, respectively were compared as an in vitro model of cancer progression. Their chemosensitivity and CSC properties were investigated. A range of in vitro assays were performed, including the side population assay, ALDEFLUOR assay, tumoursphere assay and assessment of CSC associated surface phenotypes.
- Full Text:
- Date Issued: 2018
In vitro antimalarial, antitrypanosomal and HIV-1 integrase inhibitory activities of two Cameroonian medicinal plants: Antrocaryon klaineanum (Anacardiaceae) and Diospyros conocarpa (Ebenaceae)
- Fouokeng, Y, Feusso, H M Feumo, Noundou, Xavier S, Krause, Rui W M, Teinkela, Jean E Mb, Wintjens, R, Hoppe, Heinrich C, Azebaze, Anatole G B, Vardamides, Juliette C, Isaacs, Michelle
- Authors: Fouokeng, Y , Feusso, H M Feumo , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E Mb , Wintjens, R , Hoppe, Heinrich C , Azebaze, Anatole G B , Vardamides, Juliette C , Isaacs, Michelle
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126653 , vital:35908 , https://doi.org/10.1016/j.sajb.2018.10.008
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value
- Full Text:
- Date Issued: 2018
- Authors: Fouokeng, Y , Feusso, H M Feumo , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E Mb , Wintjens, R , Hoppe, Heinrich C , Azebaze, Anatole G B , Vardamides, Juliette C , Isaacs, Michelle
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126653 , vital:35908 , https://doi.org/10.1016/j.sajb.2018.10.008
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value
- Full Text:
- Date Issued: 2018
In vivo toxicological evaluation of peptide conjugated gold nanoparticles for potential application in colorectal cancer diagnosis
- Authors: Adewale, Olusola Bolaji
- Date: 2018
- Subjects: Nanostructured materials -- Toxicology , Colon (Anatomy) -- Cancer Rectum -- Cancer
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50133 , vital:42050
- Description: Colorectal cancer (CRC) is among the leading cause of cancer-related deaths in South Africa and worldwide. Efforts are being made at finding improved diagnostic tools, as early detection (before metastasis) is a major factor in CRC treatment. Colonoscopy is the most reliable detection method, but is a specialised and expensive procedure, which is invasive, not readily available and not patient-friendly. There is a risk of developing interval cancers, as colonoscopies are performed every 10 years after the age of 40. The development of non-invasive, cost efficient and readily available diagnostic tools to CRC, which can be performed at more regular intervals, using tumour-targeting molecular imaging agents, is of urgent attention. Gold nanoparticles (AuNPs) possess several physicochemical properties, including ease of synthesis, biocompatibility, and the ability to be conjugated by ligands or biomolecules such as polyethylene glycol (PEG) and peptides for improved stability, tissue targeting and selectivity. These factors potentiate the role in biomedical applications, including cancer theranostics. Conjugation of AuNPs with a targeting molecule (e.g. antibody or peptide) is directed against cancer cell receptors. The peptides, p.C, p.L, and p.14, bind to CRC cells in vitro. Conjugation of AuNPs with these peptides should be investigated for CRC diagnosis in vivo, as it is hypothesised to allow examinations at shorter intervals through imaging techniques. This could reduce the risk of interval cancers, but before developing this novel tool, in vivo toxicity evaluations are essential. This study was therefore aimed at investigating the short- and long-term toxicological effects of a single intravenous injection of peptides (p.C, p.L, and p.14) conjugated to AuNPs in a healthy rat model. Citrate-capped AuNPs were synthesised by the citrate-reduction method, and conjugated with each peptide (biotinylated) using a combination of PEG (99% PEG-OH and 1% PEG-biotin) as a stabilising agent and linker, via biotin-streptavidin interaction. Healthy male Wistar rats were intravenously injected with 14 nm citrate-AuNPs, PEG-, p.C-PEG, p.L-PEG, and p.14-PEG-AuNPs (100 μg/kg body weight), and the control rats were injected with phosphate buffered saline. The animals were monitored for behavioural, physiological, biochemical, haematological and histological changes, as well as inflammatory responses. Phase 1 rats were sacrificed 2 weeks post-injection to determine the immediate or acute toxicity of the AuNPs, while phase 2 animals were sacrificed 12 weeks post-injection, to investigate the delayed or persistence toxicity of the AuNPs. Results revealed no significant toxicities with the citrate, PEG-, p.C-PEG and p.14-PEG-AuNPs over 12 weeks post-exposure, as evidenced by biochemical assays such as serum marker enzymes, liver and kidney function markers, and cholestatic indicators; haematological parameters; oxidative stress markers; and histopathological examinations. P.L-PEG-AuNPs, however, caused significant toxicity (p<0.05) to rats, as evidenced by increased relative liver weight, increased malondialdehyde levels, and total white blood cell counts 2 weeks post-exposure when compared to the control group. This was, however, reversed during the 12 weeks post-exposure. Further, there were no evidence of inflammatory responses, using pro-inflammatory markers including phospho interleukin 18 (IL-18) and interferon-γ (IFN-γ), as indicated by immunohistochemical staining of the liver, spleen, kidney and colon of rats 2 weeks post-injection of AuNPs. Citrate, PEG-, p.C-PEG, and p.14-PEG-AuNPs did not induce immediate, acute or persistent toxicity, while p.L-PEG-AuNPs induced a transient acute toxicity. It can be concluded that 14 nm spherical citrate-AuNPs at 100 μg/kg body weight is a good candidate for biomedical applications, and as a suitable carrier for diagnostic and/or therapeutic molecules. Combination of 99% PEG-OH and 1% PEG-biotin is an appropriate option for stabilising AuNPs in biological environment, and conjugating secondary diagnostic or therapeutic biomolecules or agents to citrate-capped AuNPs. Peptide-conjugated AuNPs are suitable for the development into a diagnostic tool for CRC in vivo.
- Full Text:
- Date Issued: 2018
- Authors: Adewale, Olusola Bolaji
- Date: 2018
- Subjects: Nanostructured materials -- Toxicology , Colon (Anatomy) -- Cancer Rectum -- Cancer
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50133 , vital:42050
- Description: Colorectal cancer (CRC) is among the leading cause of cancer-related deaths in South Africa and worldwide. Efforts are being made at finding improved diagnostic tools, as early detection (before metastasis) is a major factor in CRC treatment. Colonoscopy is the most reliable detection method, but is a specialised and expensive procedure, which is invasive, not readily available and not patient-friendly. There is a risk of developing interval cancers, as colonoscopies are performed every 10 years after the age of 40. The development of non-invasive, cost efficient and readily available diagnostic tools to CRC, which can be performed at more regular intervals, using tumour-targeting molecular imaging agents, is of urgent attention. Gold nanoparticles (AuNPs) possess several physicochemical properties, including ease of synthesis, biocompatibility, and the ability to be conjugated by ligands or biomolecules such as polyethylene glycol (PEG) and peptides for improved stability, tissue targeting and selectivity. These factors potentiate the role in biomedical applications, including cancer theranostics. Conjugation of AuNPs with a targeting molecule (e.g. antibody or peptide) is directed against cancer cell receptors. The peptides, p.C, p.L, and p.14, bind to CRC cells in vitro. Conjugation of AuNPs with these peptides should be investigated for CRC diagnosis in vivo, as it is hypothesised to allow examinations at shorter intervals through imaging techniques. This could reduce the risk of interval cancers, but before developing this novel tool, in vivo toxicity evaluations are essential. This study was therefore aimed at investigating the short- and long-term toxicological effects of a single intravenous injection of peptides (p.C, p.L, and p.14) conjugated to AuNPs in a healthy rat model. Citrate-capped AuNPs were synthesised by the citrate-reduction method, and conjugated with each peptide (biotinylated) using a combination of PEG (99% PEG-OH and 1% PEG-biotin) as a stabilising agent and linker, via biotin-streptavidin interaction. Healthy male Wistar rats were intravenously injected with 14 nm citrate-AuNPs, PEG-, p.C-PEG, p.L-PEG, and p.14-PEG-AuNPs (100 μg/kg body weight), and the control rats were injected with phosphate buffered saline. The animals were monitored for behavioural, physiological, biochemical, haematological and histological changes, as well as inflammatory responses. Phase 1 rats were sacrificed 2 weeks post-injection to determine the immediate or acute toxicity of the AuNPs, while phase 2 animals were sacrificed 12 weeks post-injection, to investigate the delayed or persistence toxicity of the AuNPs. Results revealed no significant toxicities with the citrate, PEG-, p.C-PEG and p.14-PEG-AuNPs over 12 weeks post-exposure, as evidenced by biochemical assays such as serum marker enzymes, liver and kidney function markers, and cholestatic indicators; haematological parameters; oxidative stress markers; and histopathological examinations. P.L-PEG-AuNPs, however, caused significant toxicity (p<0.05) to rats, as evidenced by increased relative liver weight, increased malondialdehyde levels, and total white blood cell counts 2 weeks post-exposure when compared to the control group. This was, however, reversed during the 12 weeks post-exposure. Further, there were no evidence of inflammatory responses, using pro-inflammatory markers including phospho interleukin 18 (IL-18) and interferon-γ (IFN-γ), as indicated by immunohistochemical staining of the liver, spleen, kidney and colon of rats 2 weeks post-injection of AuNPs. Citrate, PEG-, p.C-PEG, and p.14-PEG-AuNPs did not induce immediate, acute or persistent toxicity, while p.L-PEG-AuNPs induced a transient acute toxicity. It can be concluded that 14 nm spherical citrate-AuNPs at 100 μg/kg body weight is a good candidate for biomedical applications, and as a suitable carrier for diagnostic and/or therapeutic molecules. Combination of 99% PEG-OH and 1% PEG-biotin is an appropriate option for stabilising AuNPs in biological environment, and conjugating secondary diagnostic or therapeutic biomolecules or agents to citrate-capped AuNPs. Peptide-conjugated AuNPs are suitable for the development into a diagnostic tool for CRC in vivo.
- Full Text:
- Date Issued: 2018
In-situ synthesis of gold nanoparticles on graphene quantum dots-phthalocyanine nanoplatforms: First description of the photophysical and surface enhanced Raman scattering behaviour
- Nwahara, Nnamdi, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187638 , vital:44682 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187638 , vital:44682 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
In-situ synthesis of gold nanoparticles on graphene quantum dots-phthalocyanine nanoplatforms: First description of the photophysical and surface enhanced Raman scattering behaviour
- Nwahara, Nnamdi, Achadu, Ojodomo John, Nyokong, Tebello
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188183 , vital:44730 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
- Authors: Nwahara, Nnamdi , Achadu, Ojodomo John , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188183 , vital:44730 , xlink:href="https://doi.org/10.1016/j.jphotochem.2018.04.011"
- Description: Owing to the need for new low-dimensional molecular assemblies with tailored electronic properties, the current study presents a facile approach for the synthesis and assembly of gold nanoparticles (AuNPs) onto functional graphene quantum dots (GQDs)-phthalocyanines (Pcs) arrays and the investigation of their photophysical and surface enhanced Raman scattering (SERS) properties. The GQDs were functionalized with L-glutathione (GSH) (to form GQDs@GSH) in order to assist coupling to the low symmetry Zn tris–(tert–butyl) mono carboxyphenoxy (propionic acid) phthalocyanine (complex 1) to form 1@GQDs. The affinity of gold (Au) to sulphur (S) was exploited for the assembly of the AuNPs onto 1@GQDs platform to form 1@GQDs-AuNPs. Transmission electron microscopic investigations confirmed the formation of monodispersed, spherical Pc/GQDs@GSH/AuNPs hybrids. The nanocomposite displayed high triplet quantum yields, which translated into high singlet oxygen quantum yield as high as 87%. Furthermore, the formed composites demonstrated strong surface enhanced Raman scattering (SERS) properties with an unprecedented intrinsic maximal enhancement factor of more than 30-fold. These nanostructures also retain more than 90% of their original SERS intensities after a week of storage, displaying superb stability under ambient conditions. These results highlight the remarkable potential of this composite as a unique Raman-based PDT dosimetric agent.
- Full Text:
- Date Issued: 2018
Incidence and antibiogram fingerprints of members of the Enterobacteriaceae family recovered from river water, hospital effluents and vegetables in Chris Hani and Amathole District Municipalities in the Eastern Cape Province
- Authors: Mpaka, Lindelwa
- Date: 2018
- Subjects: Enterobacteriaceae
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: http://hdl.handle.net/10353/14549 , vital:40003
- Description: The worldwide problem of antimicrobial resistance has limited the spectrum of the current affordable and effective antimicrobials. Infections associated with resistant microorganisms impose a major threat to public health and economic stability. Globally, about 700 000 deaths every year can be accredited to antimicrobial resistance. The leading mechanism of resistance amid bacterial pathogens is the extended spectrum beta-lactamases production, which inhibits spectrum activity of several antimicrobial agents. The rise in antimicrobial resistance has compelled an urgent need of developing means of combatting resistance issue amid diseasecausing microbes. The main aim of this study is to evaluate the incidence and antibiogram fingerprints of Enterobacteriaceae recovered from hospital effluents, river water and vegetables in the Eastern Cape Province. A total of eighteen antibiotics from ten different antimicrobial classes were used to determine antibiogram profiles of the MALDI-TOF confirmed isolates. From the MALDI-TOF confirmed isolates, 60% of Enterobacter spp. and E. coli isolates displayed resistance against colistin, while Citrobacter spp. and Klebsiella spp. displayed 90% and 60% resistance against this antimicrobial respectively. These findings outline the need for the development of new antimicrobials. About 75.5% (25/33) of the presumptive Enterobacter spp. were confirmed by MALDI-TOF with 79.2% (19/24), 66.7% (2/3), 66.7% (4/6) been confirmed vegetables, hospital effluents and river water samples respectively. Likewise, about 77.8% (21/27) were confirmed as Citrobacter spp. of which 92.3% (12/13), 66.7% (2/3) and 63.6% (7/11) were from vegetables, hospital effluents and river water samples respectively. These results show that the selected vegetables were highly contaminated with resistant bacteria and thus unsafe to consume uncooked vegetable. Also river water was higly contaminated with resistant microbes, which also shows that these rivers are not fit to be used 17 as drinking water sources and recreational activities. Colistin is an antimicrobial used as a last resort of antibiotics because it exhibits broad-spectrum activity. However from the findings of the work at present, this is no longer the case. The spectrum of this antimicrobial is now reduced by Enterobacteriaceae members. To the best of my knowledge; relatively few resources have been provided to understanding, preventing, and controlling increasing antimicrobial resistance on global, national and local levels.
- Full Text:
- Date Issued: 2018
- Authors: Mpaka, Lindelwa
- Date: 2018
- Subjects: Enterobacteriaceae
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: http://hdl.handle.net/10353/14549 , vital:40003
- Description: The worldwide problem of antimicrobial resistance has limited the spectrum of the current affordable and effective antimicrobials. Infections associated with resistant microorganisms impose a major threat to public health and economic stability. Globally, about 700 000 deaths every year can be accredited to antimicrobial resistance. The leading mechanism of resistance amid bacterial pathogens is the extended spectrum beta-lactamases production, which inhibits spectrum activity of several antimicrobial agents. The rise in antimicrobial resistance has compelled an urgent need of developing means of combatting resistance issue amid diseasecausing microbes. The main aim of this study is to evaluate the incidence and antibiogram fingerprints of Enterobacteriaceae recovered from hospital effluents, river water and vegetables in the Eastern Cape Province. A total of eighteen antibiotics from ten different antimicrobial classes were used to determine antibiogram profiles of the MALDI-TOF confirmed isolates. From the MALDI-TOF confirmed isolates, 60% of Enterobacter spp. and E. coli isolates displayed resistance against colistin, while Citrobacter spp. and Klebsiella spp. displayed 90% and 60% resistance against this antimicrobial respectively. These findings outline the need for the development of new antimicrobials. About 75.5% (25/33) of the presumptive Enterobacter spp. were confirmed by MALDI-TOF with 79.2% (19/24), 66.7% (2/3), 66.7% (4/6) been confirmed vegetables, hospital effluents and river water samples respectively. Likewise, about 77.8% (21/27) were confirmed as Citrobacter spp. of which 92.3% (12/13), 66.7% (2/3) and 63.6% (7/11) were from vegetables, hospital effluents and river water samples respectively. These results show that the selected vegetables were highly contaminated with resistant bacteria and thus unsafe to consume uncooked vegetable. Also river water was higly contaminated with resistant microbes, which also shows that these rivers are not fit to be used 17 as drinking water sources and recreational activities. Colistin is an antimicrobial used as a last resort of antibiotics because it exhibits broad-spectrum activity. However from the findings of the work at present, this is no longer the case. The spectrum of this antimicrobial is now reduced by Enterobacteriaceae members. To the best of my knowledge; relatively few resources have been provided to understanding, preventing, and controlling increasing antimicrobial resistance on global, national and local levels.
- Full Text:
- Date Issued: 2018
Incidence of bacterial infections and colonisation in patients admitted to a tuberculosis hospital
- Authors: Annear, Dale John
- Date: 2018
- Subjects: Medical microbiology , Microbiology Bacteriology Tuberculosis -- Hospitals -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21482 , vital:29526
- Description: Patients with drug resistant tuberculosis (TB) are treated with multiple antibiotics including moxifloxacin, linezolid, and meropenem, which puts them at greater risk for colonisation by multi-drug resistant (MDR) bacteria. The objectives of this study were to: (i) assess the antimicrobial prescribing patterns practiced within the hospital by retrospective patient file review; (ii) determine the spectrum of bacterial colonisation in TB patients upon admission and during hospitalisation; (iii) identify bacterial isolates and evaluate antimicrobial susceptibility profiles; (iv) detect antimicrobial resistance genes in the bacterial isolates by PCR and DNA sequencing; and (v) investigate genetic relatedness of Klebsiella pneumoniae isolates using Multi Locus Sequence Typing. Nasal, groin and rectal swabs [for the detection of extended spectrum beta lactamases (EBSLs), carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)] were analysed from a cohort of patients (n=37) admitted either from the community (n = 28) or from other healthcare facilities (n=9) to a TB hospital. Swab samples were collected at admission and at four week intervals thereafter during hospitalization. Identification and antimicrobial susceptibility testing of bacterial isolates (n=62) were determined at the National Health Laboratory Services (NHLS) by the VITEK-MS and Vitek 2 systems respectively. Additional antimicrobial susceptibility testing was conducted by Sensititre Gram Negative Xtra (GNFX2) MIC plates. PCR and DNA sequencing were used for detection of resistance genes. Patients (n=13/37; 35%) were colonized by MDR bacteria (ESBLs [n=11], MRSA [n=2]) on admission. Colonization rates were lower in patients admitted from the community (9/28; 32%) compared to those transferred from other healthcare facilities (4/9; 44%). All admitted patients who did not exhibit colonization at baseline and who were resident within the hospital for longer than 4 weeks (17/37; 46% of total patients) became colonised by an ESBL-producing Enterobacteriaceae species. No patients acquired MRSA during hospitalisation. Among ESBL Enterobacteriaceae, Escherichia coli (41/62; 66%) and K. pneumoniae [14/62; 23%]) predominated. Nineteen percent (7/37) of patients demised during their hospitalization. Both the Vitek system and Sensititre Gram Negative Xtra (GNFX2) MIC plates susceptibilities were similar for most antimicrobials, however there were discrepancies for tigecycline susceptibility profiles. A high number of isolates exhibited resistance to aminoglycosides and fluoroquinolones. Genes encoding for ESBLs (CTX-M-14, CTX-M-15, SHV-28, OXA-1, and OXY-2-9) were detected among ESBL Enterobacteriaceae. Two Enterobacteriaceae isolates with reduced carbapenem susceptibility did not contain carbapenemase-encoding genes. MLST revealed unique sequence types and genetic diversity among the K. pneumoniae isolates from hospitalised patients. However, the source and colonization routes of these isolates could not be determined, which requires further investigation. This study provides insight into the spectrum of bacterial pathogen colonisation in hospitalised TB patients and suggests a review of infection control programs and practices at the TB hospital.
- Full Text:
- Date Issued: 2018
- Authors: Annear, Dale John
- Date: 2018
- Subjects: Medical microbiology , Microbiology Bacteriology Tuberculosis -- Hospitals -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/21482 , vital:29526
- Description: Patients with drug resistant tuberculosis (TB) are treated with multiple antibiotics including moxifloxacin, linezolid, and meropenem, which puts them at greater risk for colonisation by multi-drug resistant (MDR) bacteria. The objectives of this study were to: (i) assess the antimicrobial prescribing patterns practiced within the hospital by retrospective patient file review; (ii) determine the spectrum of bacterial colonisation in TB patients upon admission and during hospitalisation; (iii) identify bacterial isolates and evaluate antimicrobial susceptibility profiles; (iv) detect antimicrobial resistance genes in the bacterial isolates by PCR and DNA sequencing; and (v) investigate genetic relatedness of Klebsiella pneumoniae isolates using Multi Locus Sequence Typing. Nasal, groin and rectal swabs [for the detection of extended spectrum beta lactamases (EBSLs), carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA)] were analysed from a cohort of patients (n=37) admitted either from the community (n = 28) or from other healthcare facilities (n=9) to a TB hospital. Swab samples were collected at admission and at four week intervals thereafter during hospitalization. Identification and antimicrobial susceptibility testing of bacterial isolates (n=62) were determined at the National Health Laboratory Services (NHLS) by the VITEK-MS and Vitek 2 systems respectively. Additional antimicrobial susceptibility testing was conducted by Sensititre Gram Negative Xtra (GNFX2) MIC plates. PCR and DNA sequencing were used for detection of resistance genes. Patients (n=13/37; 35%) were colonized by MDR bacteria (ESBLs [n=11], MRSA [n=2]) on admission. Colonization rates were lower in patients admitted from the community (9/28; 32%) compared to those transferred from other healthcare facilities (4/9; 44%). All admitted patients who did not exhibit colonization at baseline and who were resident within the hospital for longer than 4 weeks (17/37; 46% of total patients) became colonised by an ESBL-producing Enterobacteriaceae species. No patients acquired MRSA during hospitalisation. Among ESBL Enterobacteriaceae, Escherichia coli (41/62; 66%) and K. pneumoniae [14/62; 23%]) predominated. Nineteen percent (7/37) of patients demised during their hospitalization. Both the Vitek system and Sensititre Gram Negative Xtra (GNFX2) MIC plates susceptibilities were similar for most antimicrobials, however there were discrepancies for tigecycline susceptibility profiles. A high number of isolates exhibited resistance to aminoglycosides and fluoroquinolones. Genes encoding for ESBLs (CTX-M-14, CTX-M-15, SHV-28, OXA-1, and OXY-2-9) were detected among ESBL Enterobacteriaceae. Two Enterobacteriaceae isolates with reduced carbapenem susceptibility did not contain carbapenemase-encoding genes. MLST revealed unique sequence types and genetic diversity among the K. pneumoniae isolates from hospitalised patients. However, the source and colonization routes of these isolates could not be determined, which requires further investigation. This study provides insight into the spectrum of bacterial pathogen colonisation in hospitalised TB patients and suggests a review of infection control programs and practices at the TB hospital.
- Full Text:
- Date Issued: 2018
Incidence of porcine circovirus type 2 and porcine parvoviruses in swine herds of some communities in Eastern Cape, South Africa
- Authors: Afolabi, Kayode Olayinka
- Date: 2018
- Subjects: Swine -- Diseases Swine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9691 , vital:34820
- Description: Porcine circovirus type 2 (PCV2) is one of the swine pathogens of global economic importance. Since its first detection in early 1990s as the main etiologic agent of porcine multisystemic wasting syndrome (PMWS) and many other porcine circovirus-associated diseases (PCVAD), the virus has been extensively studied and has been found to be present in virtually all the pig producing countries of the world. As a viral pathogen that brings about clinical diseases aided by co-infecting pathogens, the involvement of many other viral agents including porcine parvoviruses (PPVs) have caught the attention of stakeholders worldwide. However, no surveillance study of the viral pathogens has been carried out in South Africa as there are little or no information on their prevalence in the swine herds of the country. This present study therefore aimed at detection and molecular characterization of PCV2 and PPVs in swine herds of some selected communities in Eastern Cape Province, South Africa. A total of 375 field samples were collected from seven commercial and communal farms from three District Municipalities of Eastern Cape, South Africa between 2015 and 2016. Structured questionnaires were also administered to each farm at the time of sample collection to obtain some important information relating to health status and farm management practices in the sampled farms. With the aid of conventional PCR method, 339 samples were initially screened for the presence of PCV2; positive amplicons were sequenced and obtained partial genomes of the virus were preliminarily analyzed. In order to obtain the complete genomes of the virus, four overlapping primer pairs were used to amplify the full-genome of PCV2 from the initial positive samples; amplified genomes were sequenced using the Sanger methods, sequenced PCV2 genomes were assembled and characterized. Furthermore, the prevalences of some designated PPVs in the sampled farms were obtained using 110 samples randomly selected from the previously archived samples and screened with 6 different primer pairs specific for the detection of 7 PPVs. All the amplified parvoviruses’ genomes were sequenced; their sequenced partial genomes were subsequently base-culled and analysed. The data obtained revealed that 54/339 (15.93 percent) samples from the swine herds were positive for PCV2; whereas the degree of occurrence of the viral pathogen as observed at farm level ranges from approximately 5.6 to 60 percent. The majority 15/17 (88 percent) of the analyzed partial sequences were found clustering with other PCV2b strains in the phylogenetic analysis. More interestingly, two other sequences obtained were also found clustering within PCV2d genotype in the initial screening and analysis. Furthermore, 15 complete PCV2 genomes were successfully amplified, sequenced and assembled. NJ and ML phylogenetic analysis of the complete ORF2 gene and full genomes unanimously showed 11 of the assembled genomes belonging to genotype PCV2b. Another 3 of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (PCV2d) strains from different parts of the world. The last sequence however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2-IM2) recently identified in a global PCV2 strains phylogenetic analysis. Other genetic analyses including multiple sequence alignment and p-distance analysis also confirmed the outcomes of the phylogenetic analyses of the complete capsid gene and fullgenomes of the virus. On the other hand, the findings of the molecular profiling for PPVs showed that all the screened parvoviruses were present in the study area, having prevalence of 29.1 percent (PPV1), 21.8 percent (PPV2), 5.5 percent (PPV3), 43.6 percent (PPV4), 21.8 percent (PBo-likeV) and 44.6 percent for PBoV1 and PBoV2. Double infection of the screened PPVs was observed to be very rampant among the pigs as high as 20/110 (18.2 percent) for PPV2/PPV4 and PPV4/PBoV; followed by 19/110 (17.3 percent) of the samples for PPV1/PPV4 and PPV1/PBoV. Three of the viruses were found simultaneously in 19 of the screened samples representing 17.3 percent, whereas 8 (7.3 percent) samples were positive for four of the viruses. Phylogenetic analyses of PPV1, PPV2 and PBoVs 1 and 2 were conducted with two major clades homologous for each of them. This is the first report of PCV2 in swine herds of the Province and the first detection of PCV2b, PCV2d and PCV2-IM2 strains in South African swine herds. It follows the first reported case of PCV2a in an outbreak of porcine multisystemic wasting syndrome (PMWS) in Gauteng Province, South Africa over two decades ago. Also, this is the first major epidemiologic study on PPVs in the country following the initial case study of 1975. These findings confirmed the presence of the allimportant viral pathogens among pigs and also give preliminary insights into the possibility of co-infections of the pathogens in the studied area. This could however result in a serious large scale outbreak of devastating disease(s) associated with the viral pathogens, thereby ultimately resulting in huge economic losses if no appropriate measures are taken to effectively curb their spread across the country.
- Full Text:
- Date Issued: 2018
- Authors: Afolabi, Kayode Olayinka
- Date: 2018
- Subjects: Swine -- Diseases Swine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9691 , vital:34820
- Description: Porcine circovirus type 2 (PCV2) is one of the swine pathogens of global economic importance. Since its first detection in early 1990s as the main etiologic agent of porcine multisystemic wasting syndrome (PMWS) and many other porcine circovirus-associated diseases (PCVAD), the virus has been extensively studied and has been found to be present in virtually all the pig producing countries of the world. As a viral pathogen that brings about clinical diseases aided by co-infecting pathogens, the involvement of many other viral agents including porcine parvoviruses (PPVs) have caught the attention of stakeholders worldwide. However, no surveillance study of the viral pathogens has been carried out in South Africa as there are little or no information on their prevalence in the swine herds of the country. This present study therefore aimed at detection and molecular characterization of PCV2 and PPVs in swine herds of some selected communities in Eastern Cape Province, South Africa. A total of 375 field samples were collected from seven commercial and communal farms from three District Municipalities of Eastern Cape, South Africa between 2015 and 2016. Structured questionnaires were also administered to each farm at the time of sample collection to obtain some important information relating to health status and farm management practices in the sampled farms. With the aid of conventional PCR method, 339 samples were initially screened for the presence of PCV2; positive amplicons were sequenced and obtained partial genomes of the virus were preliminarily analyzed. In order to obtain the complete genomes of the virus, four overlapping primer pairs were used to amplify the full-genome of PCV2 from the initial positive samples; amplified genomes were sequenced using the Sanger methods, sequenced PCV2 genomes were assembled and characterized. Furthermore, the prevalences of some designated PPVs in the sampled farms were obtained using 110 samples randomly selected from the previously archived samples and screened with 6 different primer pairs specific for the detection of 7 PPVs. All the amplified parvoviruses’ genomes were sequenced; their sequenced partial genomes were subsequently base-culled and analysed. The data obtained revealed that 54/339 (15.93 percent) samples from the swine herds were positive for PCV2; whereas the degree of occurrence of the viral pathogen as observed at farm level ranges from approximately 5.6 to 60 percent. The majority 15/17 (88 percent) of the analyzed partial sequences were found clustering with other PCV2b strains in the phylogenetic analysis. More interestingly, two other sequences obtained were also found clustering within PCV2d genotype in the initial screening and analysis. Furthermore, 15 complete PCV2 genomes were successfully amplified, sequenced and assembled. NJ and ML phylogenetic analysis of the complete ORF2 gene and full genomes unanimously showed 11 of the assembled genomes belonging to genotype PCV2b. Another 3 of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (PCV2d) strains from different parts of the world. The last sequence however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2-IM2) recently identified in a global PCV2 strains phylogenetic analysis. Other genetic analyses including multiple sequence alignment and p-distance analysis also confirmed the outcomes of the phylogenetic analyses of the complete capsid gene and fullgenomes of the virus. On the other hand, the findings of the molecular profiling for PPVs showed that all the screened parvoviruses were present in the study area, having prevalence of 29.1 percent (PPV1), 21.8 percent (PPV2), 5.5 percent (PPV3), 43.6 percent (PPV4), 21.8 percent (PBo-likeV) and 44.6 percent for PBoV1 and PBoV2. Double infection of the screened PPVs was observed to be very rampant among the pigs as high as 20/110 (18.2 percent) for PPV2/PPV4 and PPV4/PBoV; followed by 19/110 (17.3 percent) of the samples for PPV1/PPV4 and PPV1/PBoV. Three of the viruses were found simultaneously in 19 of the screened samples representing 17.3 percent, whereas 8 (7.3 percent) samples were positive for four of the viruses. Phylogenetic analyses of PPV1, PPV2 and PBoVs 1 and 2 were conducted with two major clades homologous for each of them. This is the first report of PCV2 in swine herds of the Province and the first detection of PCV2b, PCV2d and PCV2-IM2 strains in South African swine herds. It follows the first reported case of PCV2a in an outbreak of porcine multisystemic wasting syndrome (PMWS) in Gauteng Province, South Africa over two decades ago. Also, this is the first major epidemiologic study on PPVs in the country following the initial case study of 1975. These findings confirmed the presence of the allimportant viral pathogens among pigs and also give preliminary insights into the possibility of co-infections of the pathogens in the studied area. This could however result in a serious large scale outbreak of devastating disease(s) associated with the viral pathogens, thereby ultimately resulting in huge economic losses if no appropriate measures are taken to effectively curb their spread across the country.
- Full Text:
- Date Issued: 2018
Incorporation of metal free and Ga 5, 10, 15, 20-tetrakis (4-bromophenyl) porphyrin into Pluronic F127-folic acid micelles
- Managa, Muthumuni, Ngoy, Bucolome P, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Managa, Muthumuni , Ngoy, Bucolome P , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233256 , vital:50073 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.09.045"
- Description: ClGa 5,10,15,20-Tetrakis (4-bromophenyl) porphyrinato (ClGaTBrPP) and its metal free derivative were successfully synthesized and incorporated into Pluronic F127 polymeric micelles that has been conjugated to folic acid (FA) to form ClGaTBrPP-F127-FA (or H2TBrPP-F127-FA). For comparison, ClGaTBrPP-F127 and H2TBrPP-F127 (without FA) were also formed. The singlet oxygen quantum yield for ClGaTBrPP-F127-FA was higher (ΦΔ = 0.44) than that of H2TBrPP-F127-FA (ΦΔ = 0.37), due to the heavy atom effect of Ga in the former which encourages intersystem crossing to the triplet state. The same applies to ClGaTBrPP-F127 (ΦΔ = 0.47) and H2TBrPP-F127 (ΦΔ = 0.41). Thus, ΦΔ values decreased in the presence of FA, but still high enough for practical application of the nanodrug system. The binding constants Kb were determined to be 1.08 × 104 M−1, 2.51 × 105 M−1, 1.52 × 103 and 2.68 × 103 for H2TBrPP+F127-FA, ClGaTBrPP+F127-FA, ClGaTBrPP-F127 and H2TBrPP-F127, respectively. The Kp values were determined in biphasic octanol and water system.
- Full Text:
- Date Issued: 2018
- Authors: Managa, Muthumuni , Ngoy, Bucolome P , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233256 , vital:50073 , xlink:href="https://doi.org/10.1016/j.jlumin.2017.09.045"
- Description: ClGa 5,10,15,20-Tetrakis (4-bromophenyl) porphyrinato (ClGaTBrPP) and its metal free derivative were successfully synthesized and incorporated into Pluronic F127 polymeric micelles that has been conjugated to folic acid (FA) to form ClGaTBrPP-F127-FA (or H2TBrPP-F127-FA). For comparison, ClGaTBrPP-F127 and H2TBrPP-F127 (without FA) were also formed. The singlet oxygen quantum yield for ClGaTBrPP-F127-FA was higher (ΦΔ = 0.44) than that of H2TBrPP-F127-FA (ΦΔ = 0.37), due to the heavy atom effect of Ga in the former which encourages intersystem crossing to the triplet state. The same applies to ClGaTBrPP-F127 (ΦΔ = 0.47) and H2TBrPP-F127 (ΦΔ = 0.41). Thus, ΦΔ values decreased in the presence of FA, but still high enough for practical application of the nanodrug system. The binding constants Kb were determined to be 1.08 × 104 M−1, 2.51 × 105 M−1, 1.52 × 103 and 2.68 × 103 for H2TBrPP+F127-FA, ClGaTBrPP+F127-FA, ClGaTBrPP-F127 and H2TBrPP-F127, respectively. The Kp values were determined in biphasic octanol and water system.
- Full Text:
- Date Issued: 2018