The constitutional right of access to social security
- Authors: Govindjee, Avinash
- Date: 2001
- Subjects: Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11061 , http://hdl.handle.net/10948/280 , Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Description: The inclusion of the right of access to social security in the Constitution did not meet with wholehearted approval in South Africa. This right, however, is of vital importance for the future upliftment of the country. The present social security system is based upon a clear distinction between social assistance and social insurance. There is a gap in current social security provisions in that the unemployed middle aged individual is not covered. Unemployment itself is one of the greatest challenges obscuring the implementation of a comprehensive social security system. The Constitutional right is to have ‘access’ to social security and the amount of resources at the state’s disposal is directly related to increasing this right, although it is true that a number of available resources are misspent. The state must take reasonable legislative and other measures, within its available resources, to achieve the progressive realisation of the right of access to social security. The principles of solidarity and ubuntu must be cultivated so that national social development becomes a concern for all citizens. There are numerous problems facing South Africans in attaining the goal of access to social security – even if national social development does become a priority. Budgetary constraints, poverty, unemployment, HIV/Aids and foreigners are examples of these. By making social security a priority for everyone, existing ideas (almost all of which have merit) may be converted into long-term solutions for poverty and unemployment. Currently, numerous opportunities to salvage the situation are being overlooked as a result of the lack of a comprehensive and structured plan to better the access to social security. The constitutional right of access to social security is enforceable, although the jurisprudence in this field remains underdeveloped. Conditions are currently favourable, within the country and beyond its borders, for an imaginative and concerted attempt to be made to find potential solutions. It is possible for resources to be increased and for tax benefits to be incorporated for businesses which have the capacity to contribute. The issue of defence spending is controversial, but could hold the key to lowering unemployment. Should jobs be created, it is likely that they will initially be of a temporary nature. Consequently, provisions are needed to ensure some guarantee of income in the lacuna between when a job is lost and another found. Ultimately, one thing is certain: the constitutional right of access to social security will only be complete once the people who are recipients of this right make sacrifices and create corresponding duties for themselves to ensure that the next generation of inhabitants of this country are not facing similar problems. The state’s goal should be to ensure that the basic rights which all people enjoy in terms of the Constitution (in particular the other socio-economic rights) are guaranteed for the duration of their existence, even if the level of benefits received by such people is low.
- Full Text:
- Date Issued: 2001
- Authors: Govindjee, Avinash
- Date: 2001
- Subjects: Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11061 , http://hdl.handle.net/10948/280 , Social security -- Law and legislation -- South Africa , South Africa -- Social policy
- Description: The inclusion of the right of access to social security in the Constitution did not meet with wholehearted approval in South Africa. This right, however, is of vital importance for the future upliftment of the country. The present social security system is based upon a clear distinction between social assistance and social insurance. There is a gap in current social security provisions in that the unemployed middle aged individual is not covered. Unemployment itself is one of the greatest challenges obscuring the implementation of a comprehensive social security system. The Constitutional right is to have ‘access’ to social security and the amount of resources at the state’s disposal is directly related to increasing this right, although it is true that a number of available resources are misspent. The state must take reasonable legislative and other measures, within its available resources, to achieve the progressive realisation of the right of access to social security. The principles of solidarity and ubuntu must be cultivated so that national social development becomes a concern for all citizens. There are numerous problems facing South Africans in attaining the goal of access to social security – even if national social development does become a priority. Budgetary constraints, poverty, unemployment, HIV/Aids and foreigners are examples of these. By making social security a priority for everyone, existing ideas (almost all of which have merit) may be converted into long-term solutions for poverty and unemployment. Currently, numerous opportunities to salvage the situation are being overlooked as a result of the lack of a comprehensive and structured plan to better the access to social security. The constitutional right of access to social security is enforceable, although the jurisprudence in this field remains underdeveloped. Conditions are currently favourable, within the country and beyond its borders, for an imaginative and concerted attempt to be made to find potential solutions. It is possible for resources to be increased and for tax benefits to be incorporated for businesses which have the capacity to contribute. The issue of defence spending is controversial, but could hold the key to lowering unemployment. Should jobs be created, it is likely that they will initially be of a temporary nature. Consequently, provisions are needed to ensure some guarantee of income in the lacuna between when a job is lost and another found. Ultimately, one thing is certain: the constitutional right of access to social security will only be complete once the people who are recipients of this right make sacrifices and create corresponding duties for themselves to ensure that the next generation of inhabitants of this country are not facing similar problems. The state’s goal should be to ensure that the basic rights which all people enjoy in terms of the Constitution (in particular the other socio-economic rights) are guaranteed for the duration of their existence, even if the level of benefits received by such people is low.
- Full Text:
- Date Issued: 2001
The distinction between a contract of employment and a contract with an independent contractor
- Authors: Slater, Henry John
- Date: 2001
- Subjects: Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11060 , http://hdl.handle.net/10948/276 , Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Description: The purpose of this treatise was to determine the distinction between the contract of service (employment) and the contract of work (independent contractor). A comprehensive literary survey was undertaken so as to establish if such a distinction does indeed exist. A logical point of departure was to study the contract of service and determine how the employment relationship is established by it. It is also necessary to establish under what circumstances a contract may be terminated and what the rights and obligations of the parties to the contract were. The contract between the parties will determine remedies to the breach of contract or applicability of labour legislation. It is also necessary to establish the definition of an employee under various statutes so as to understand what remedies exist should rights be infringed upon. Statutes considered include the Constitution of the Republic of South Africa, Labour Relations Act, Basic Conditions of Employment Act, Employment Equity Act, Unemployment Insurance Act, Compensation for Occupational Injuries and Diseases Act, Skills Development Act and the Income Tax Act. The effect of insolvency of the employer on the employee is also discussed. Outsourcing has played a major role in the emergence of the independent contractor. This phenomenon is considered from the point of the employer in terms of the reasons for choosing the option of outsourcing and the associated risks. The employee perspective is also dealt with in terms of why an employee would change his/her employment status. The various tests historically applied to determine the status of a worker is also discussed. These include the control, organisation, dominant impression and economic tests. Currently the dominant impression test is the one that is being applied to determine the employment relationship. Extensive reference was made to case law. United States of America cases are referred to with specific reference to the 20 Factor Test applied by the Internal Revenue Service. South African case law is dealt wit in terms of enforcement of Bargaining Council agreements, commission-earning persons, payment for services rendered, the intention of the parties and the identity of the true employer. The emergence of the dependent contractor is also addressed. This form of worker normally falls outside of the protection of labour legislation and social security. Amendments have been proposed to various statutes to remedy the situation in South Africa. A final aspect that is dealt with is that of vicarious liability. The applicability of this aspect lies in the liability of the employer for damages inflicted by the employee.
- Full Text:
- Date Issued: 2001
- Authors: Slater, Henry John
- Date: 2001
- Subjects: Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11060 , http://hdl.handle.net/10948/276 , Labor contract -- South Africa , Independent contractors -- South Africa , Contracts -- South Africa -- Cases , Liability (Law) -- South Africa , Labor laws and legislation -- South Africa
- Description: The purpose of this treatise was to determine the distinction between the contract of service (employment) and the contract of work (independent contractor). A comprehensive literary survey was undertaken so as to establish if such a distinction does indeed exist. A logical point of departure was to study the contract of service and determine how the employment relationship is established by it. It is also necessary to establish under what circumstances a contract may be terminated and what the rights and obligations of the parties to the contract were. The contract between the parties will determine remedies to the breach of contract or applicability of labour legislation. It is also necessary to establish the definition of an employee under various statutes so as to understand what remedies exist should rights be infringed upon. Statutes considered include the Constitution of the Republic of South Africa, Labour Relations Act, Basic Conditions of Employment Act, Employment Equity Act, Unemployment Insurance Act, Compensation for Occupational Injuries and Diseases Act, Skills Development Act and the Income Tax Act. The effect of insolvency of the employer on the employee is also discussed. Outsourcing has played a major role in the emergence of the independent contractor. This phenomenon is considered from the point of the employer in terms of the reasons for choosing the option of outsourcing and the associated risks. The employee perspective is also dealt with in terms of why an employee would change his/her employment status. The various tests historically applied to determine the status of a worker is also discussed. These include the control, organisation, dominant impression and economic tests. Currently the dominant impression test is the one that is being applied to determine the employment relationship. Extensive reference was made to case law. United States of America cases are referred to with specific reference to the 20 Factor Test applied by the Internal Revenue Service. South African case law is dealt wit in terms of enforcement of Bargaining Council agreements, commission-earning persons, payment for services rendered, the intention of the parties and the identity of the true employer. The emergence of the dependent contractor is also addressed. This form of worker normally falls outside of the protection of labour legislation and social security. Amendments have been proposed to various statutes to remedy the situation in South Africa. A final aspect that is dealt with is that of vicarious liability. The applicability of this aspect lies in the liability of the employer for damages inflicted by the employee.
- Full Text:
- Date Issued: 2001
The goddess, the witch and the bitch : three studies in the perception of women
- Authors: Hare, Nicola Tracy
- Date: 2001
- Subjects: Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10986 , http://hdl.handle.net/10948/278 , Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Description: In the minds of many people all over the world, women are ‘second class citizens’, standing accused of the downfall of mankind ever since Eve allegedly ate the apple. Even amongst those who do not openly denigrate women, there are many who do so in other, more subtle ways even if they are unaware of it. This study proposes to challenge such a view of women by exposing the ways in which perceptions of women are constructed by society, which frequently wants to maintain the status quo of male dominance. This study employs a feminist approach in examining this gynocentric theme, along with cultural studies which, with its focus on power relations and ways of decentring power structures, is also clearly of use. In addition, this multidisciplinary approach of cultural studies offers the possibility of studying literary texts as well as popular culture. Three specific time periods are examined, with a view to uncovering negative perceptions of women and ways that women can resist such attempts to control them. In chapter one, the focus turns to contemporary perceptions of prehistoric women and the ways that so-called ‘objective’ science has failed to represent women accurately. Similarly, ‘objective’ accounts of Goddess-worship – which frequently fail to examine this phenomenon adequately – are revisited. Alice Walker’s The Temple of My Familiar (1989) is discussed as a text which acts as a site of resistance to societally-informed perceptions. Chapter two continues this investigation by turning to the concept of the witch and its maligned association with women. Woman and witchcraft, having been associated for centuries, are investigated as a pairing which frequently results because iii of attempts to control women by androcentric society. In such situations, the practising of witchcraft can actually become a form of resistance to patriarchy. The pernicious effect of society’s need to purge itself – by witch hunts – of witches is also investigated. The Devil’s Chimney (1997) by Anne Landsman and “The prophetess” (1994) by Njabulo S. Ndebele are discussed as texts which examine fictionalised South African versions of this phenomenon. Sinead O’Connor, the Irish singer, is the ‘bitch’ discussed in chapter three. She is examined as a woman who offers strong and on-going resistance to patriarchal ways of thinking which would ‘box’ women in. This singer refuses to accept societal roles which are offered to women and so offers means of resistance to patriarchy, many of which are discussed in this chapter. This study concludes that it is the responsibility of women to resist patriarchy and to define roles for themselves. The three chapters examine various means of resistance and offer women insight into the forms of opposition they themselves can take.
- Full Text:
- Date Issued: 2001
- Authors: Hare, Nicola Tracy
- Date: 2001
- Subjects: Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10986 , http://hdl.handle.net/10948/278 , Feminism in literature , Women's rights in literature , Feminism and literature , Patriarchy in literature
- Description: In the minds of many people all over the world, women are ‘second class citizens’, standing accused of the downfall of mankind ever since Eve allegedly ate the apple. Even amongst those who do not openly denigrate women, there are many who do so in other, more subtle ways even if they are unaware of it. This study proposes to challenge such a view of women by exposing the ways in which perceptions of women are constructed by society, which frequently wants to maintain the status quo of male dominance. This study employs a feminist approach in examining this gynocentric theme, along with cultural studies which, with its focus on power relations and ways of decentring power structures, is also clearly of use. In addition, this multidisciplinary approach of cultural studies offers the possibility of studying literary texts as well as popular culture. Three specific time periods are examined, with a view to uncovering negative perceptions of women and ways that women can resist such attempts to control them. In chapter one, the focus turns to contemporary perceptions of prehistoric women and the ways that so-called ‘objective’ science has failed to represent women accurately. Similarly, ‘objective’ accounts of Goddess-worship – which frequently fail to examine this phenomenon adequately – are revisited. Alice Walker’s The Temple of My Familiar (1989) is discussed as a text which acts as a site of resistance to societally-informed perceptions. Chapter two continues this investigation by turning to the concept of the witch and its maligned association with women. Woman and witchcraft, having been associated for centuries, are investigated as a pairing which frequently results because iii of attempts to control women by androcentric society. In such situations, the practising of witchcraft can actually become a form of resistance to patriarchy. The pernicious effect of society’s need to purge itself – by witch hunts – of witches is also investigated. The Devil’s Chimney (1997) by Anne Landsman and “The prophetess” (1994) by Njabulo S. Ndebele are discussed as texts which examine fictionalised South African versions of this phenomenon. Sinead O’Connor, the Irish singer, is the ‘bitch’ discussed in chapter three. She is examined as a woman who offers strong and on-going resistance to patriarchal ways of thinking which would ‘box’ women in. This singer refuses to accept societal roles which are offered to women and so offers means of resistance to patriarchy, many of which are discussed in this chapter. This study concludes that it is the responsibility of women to resist patriarchy and to define roles for themselves. The three chapters examine various means of resistance and offer women insight into the forms of opposition they themselves can take.
- Full Text:
- Date Issued: 2001
The right of the HIV/AIDS patient to treatment
- Authors: Hoffmann, Toinette
- Date: 2001
- Subjects: AIDS (Disease) -- Patients -- Legal status, Laws, etc. -- South Africa , Hiv-positive Persons -- Legal status, Laws, etc. -- South Africa , AIDS (Disease) -- Government policy -- South Africa , AIDS (Disease) -- Treatment , AIDS (Disease) -- Social aspects
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11042 , http://hdl.handle.net/10948/277 , AIDS (Disease) -- Patients -- Legal status, Laws, etc. -- South Africa , Hiv-positive Persons -- Legal status, Laws, etc. -- South Africa , AIDS (Disease) -- Government policy -- South Africa , AIDS (Disease) -- Treatment , AIDS (Disease) -- Social aspects
- Description: The objective of this treatise is to establish whether a right to social security exists in South Africa, which would entitle HIV positive persons in South Africa citizens to medical care. A study was made of various articles in journals and on the Internet to determine the South African government's policy on a right to social security and to providing medical treatment. It was found that South Africa lacks an integrated, holistic approach to social security and does not guarantee the right to social security, merely the right to have access to social security. The same was found with the right to medical care. Although there seems to be a general right to medical care which extends to and includes HIV-positive patients, the state merely guarantees the right to apply for medical treatment but does not guarantee the granting thereof. It is submitted that the Department of Health's refusal to implement a vertical transmission prevention programme and the failure to offer treatment as an alternative, for whatever reason, is "penny wise and pound foolish". In the long run more money is spent dealing with pediatric AIDS. It was further found that although the government attempted to lay a groundwork with the formulation and acceptance of the national AIDS plan, the successful implementation thereof is seriously hindered due to the lack of inter- and intra-departmental collaboration, essential health services and funding.
- Full Text:
- Date Issued: 2001
- Authors: Hoffmann, Toinette
- Date: 2001
- Subjects: AIDS (Disease) -- Patients -- Legal status, Laws, etc. -- South Africa , Hiv-positive Persons -- Legal status, Laws, etc. -- South Africa , AIDS (Disease) -- Government policy -- South Africa , AIDS (Disease) -- Treatment , AIDS (Disease) -- Social aspects
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11042 , http://hdl.handle.net/10948/277 , AIDS (Disease) -- Patients -- Legal status, Laws, etc. -- South Africa , Hiv-positive Persons -- Legal status, Laws, etc. -- South Africa , AIDS (Disease) -- Government policy -- South Africa , AIDS (Disease) -- Treatment , AIDS (Disease) -- Social aspects
- Description: The objective of this treatise is to establish whether a right to social security exists in South Africa, which would entitle HIV positive persons in South Africa citizens to medical care. A study was made of various articles in journals and on the Internet to determine the South African government's policy on a right to social security and to providing medical treatment. It was found that South Africa lacks an integrated, holistic approach to social security and does not guarantee the right to social security, merely the right to have access to social security. The same was found with the right to medical care. Although there seems to be a general right to medical care which extends to and includes HIV-positive patients, the state merely guarantees the right to apply for medical treatment but does not guarantee the granting thereof. It is submitted that the Department of Health's refusal to implement a vertical transmission prevention programme and the failure to offer treatment as an alternative, for whatever reason, is "penny wise and pound foolish". In the long run more money is spent dealing with pediatric AIDS. It was further found that although the government attempted to lay a groundwork with the formulation and acceptance of the national AIDS plan, the successful implementation thereof is seriously hindered due to the lack of inter- and intra-departmental collaboration, essential health services and funding.
- Full Text:
- Date Issued: 2001
On using AMOS, EQS, LISREL, Mx, RAMONA and SEPATH for structural equation modeling
- Authors: Peprah, Syvester
- Date: 2000
- Subjects: Latent variables , Multivariate analysis , Mathematical statistics -- computer programs
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11082 , http://hdl.handle.net/10948/279 , Latent variables , Multivariate analysis , Mathematical statistics -- computer programs
- Description: Structural Equation Modeling is a common name for the statistical analysis of Structural Equation Models. Structural Equation Models are models that specify relationships between a set of variables and can be specified by means of path diagrams. A number of Structural Equation Modeling programs have been developed. These include, amongst others, AMOS, EQS, LISREL, Mx, RAMONA and SEPATH. A number of studies have been published on the use of some of the applications mentioned above. They include, amongst others, Brown (1986), Waller (1993) and Kano (1997). Structural Equation Models are increasingly being used in the social, economic and behavioral sciences. More and more people are therefore making use of one or more of the Structural Equation Modeling applications on the market. This study is performed with the aim of using each of the Structural Equation Modeling applications AMOS, EQS, LISREL, Mx, RAMONA and SEPATH for the first time and document the experience, joy and the difficulties encountered while using them. This treatise is different from the comparisons already published in that it is based on the use of AMOS, EQS, LISREL, Mx, RAMONA and SEPATH to fit a Structural Equation Model for peer influences on ambition, which is specified for data obtained by Duncan, Haller and Portes (1971), by myself as a first time user of each of the programs mentioned. The impressive features as well as the difficulties encountered are listed for each application. Recommendations for possible improvements to the various applications are also proposed. Finally, recommendations for future studies on the use of Structural Equation Modeling programs are made.
- Full Text:
- Date Issued: 2000
- Authors: Peprah, Syvester
- Date: 2000
- Subjects: Latent variables , Multivariate analysis , Mathematical statistics -- computer programs
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11082 , http://hdl.handle.net/10948/279 , Latent variables , Multivariate analysis , Mathematical statistics -- computer programs
- Description: Structural Equation Modeling is a common name for the statistical analysis of Structural Equation Models. Structural Equation Models are models that specify relationships between a set of variables and can be specified by means of path diagrams. A number of Structural Equation Modeling programs have been developed. These include, amongst others, AMOS, EQS, LISREL, Mx, RAMONA and SEPATH. A number of studies have been published on the use of some of the applications mentioned above. They include, amongst others, Brown (1986), Waller (1993) and Kano (1997). Structural Equation Models are increasingly being used in the social, economic and behavioral sciences. More and more people are therefore making use of one or more of the Structural Equation Modeling applications on the market. This study is performed with the aim of using each of the Structural Equation Modeling applications AMOS, EQS, LISREL, Mx, RAMONA and SEPATH for the first time and document the experience, joy and the difficulties encountered while using them. This treatise is different from the comparisons already published in that it is based on the use of AMOS, EQS, LISREL, Mx, RAMONA and SEPATH to fit a Structural Equation Model for peer influences on ambition, which is specified for data obtained by Duncan, Haller and Portes (1971), by myself as a first time user of each of the programs mentioned. The impressive features as well as the difficulties encountered are listed for each application. Recommendations for possible improvements to the various applications are also proposed. Finally, recommendations for future studies on the use of Structural Equation Modeling programs are made.
- Full Text:
- Date Issued: 2000
Ostrich calpastatin purification and partial characterization of the liver inhibitor
- Authors: Roman, Henry James
- Date: 2000
- Subjects: Calpastatin , Protease inhibitors , Ion exchange chromatography , Ostriches
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11090 , http://hdl.handle.net/10948/d1015522
- Description: The isolation and purification of calpastatin from ostrich liver is presented, along with its physicochemical and kinetic properties. By using extraction from liver, ion-exchange chromatography on DEAE-Toyopearl, heating to 90 °C for 10 min and rechromatography on Toyopearl Super-Q 650 S, ostrich calpastatin was isolated and purified from ostrich liver. The purified intact calpastatin showed homogeneity on SDS-PAGE (Mr of 105.6 K). Amino acid analysis showed that ostrich calpastatin resembled that of rabbit liver and human erythrocyte calpastatin. An N-terminal sequence could not be obtained because the N-terminus was found to be blocked by an as yet unknown amino acid residue. The Mr values of degradative forms of ostrich liver calpastatin were determined to be 56 K and 90 K. By using PAG-IEF the pI of the intact form was determined to be 5.1. Ostrich liver calpastatin behaved characteristically like other calpastatins during kinetic analysis. Calpastatin inhibited calpain from pH 6 to 9 and was found to be unaffected by temperatures as high as 100 °C. Calpastatin also inhibited calpain activity at Ca2+ concentrations ranging from 1 to 10 mM. The inhibitor was shown to be phosphorylated because after incubation with alkaline phosphatase there was a decrease in inhibitory activity. No inhibitory effects were detected against other proteases such as chymotrypsin and trypsin, with both proteases inactivating calpastatin completely. Ostrich liver calpain was shown to have a pH optimum of 7.5 and a temperature optimum of 30 °C. In terms of its thermodynamic properties it resembled that of other ostrich proteases; DH, DS and DG being 47.07 kJ/mol, -91.1 J/mol/K and 74.237 kJ/mol, respectively. Ostrich liver calpain showed a Km of 0.14 % (w/v). The enzyme was active at both milli- and micro-molar concentrations of Ca2+. Ostrich liver calpastatin showed many physical, chemical and kinetic properties similar to those of other known calpastatins.
- Full Text: false
- Date Issued: 2000
- Authors: Roman, Henry James
- Date: 2000
- Subjects: Calpastatin , Protease inhibitors , Ion exchange chromatography , Ostriches
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11090 , http://hdl.handle.net/10948/d1015522
- Description: The isolation and purification of calpastatin from ostrich liver is presented, along with its physicochemical and kinetic properties. By using extraction from liver, ion-exchange chromatography on DEAE-Toyopearl, heating to 90 °C for 10 min and rechromatography on Toyopearl Super-Q 650 S, ostrich calpastatin was isolated and purified from ostrich liver. The purified intact calpastatin showed homogeneity on SDS-PAGE (Mr of 105.6 K). Amino acid analysis showed that ostrich calpastatin resembled that of rabbit liver and human erythrocyte calpastatin. An N-terminal sequence could not be obtained because the N-terminus was found to be blocked by an as yet unknown amino acid residue. The Mr values of degradative forms of ostrich liver calpastatin were determined to be 56 K and 90 K. By using PAG-IEF the pI of the intact form was determined to be 5.1. Ostrich liver calpastatin behaved characteristically like other calpastatins during kinetic analysis. Calpastatin inhibited calpain from pH 6 to 9 and was found to be unaffected by temperatures as high as 100 °C. Calpastatin also inhibited calpain activity at Ca2+ concentrations ranging from 1 to 10 mM. The inhibitor was shown to be phosphorylated because after incubation with alkaline phosphatase there was a decrease in inhibitory activity. No inhibitory effects were detected against other proteases such as chymotrypsin and trypsin, with both proteases inactivating calpastatin completely. Ostrich liver calpain was shown to have a pH optimum of 7.5 and a temperature optimum of 30 °C. In terms of its thermodynamic properties it resembled that of other ostrich proteases; DH, DS and DG being 47.07 kJ/mol, -91.1 J/mol/K and 74.237 kJ/mol, respectively. Ostrich liver calpain showed a Km of 0.14 % (w/v). The enzyme was active at both milli- and micro-molar concentrations of Ca2+. Ostrich liver calpastatin showed many physical, chemical and kinetic properties similar to those of other known calpastatins.
- Full Text: false
- Date Issued: 2000
Outsourcing for competitive advantage : an evaluation of an owner driver proposition in a South African removals company
- Authors: Coleman, Belinda
- Date: 2000
- Subjects: Contracting out -- South Africa , Storage and removal trade -- Subcontracting -- South Africa , Trucking -- South Africa , Benchmarking (Management) -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11002 , http://hdl.handle.net/10948/d1015540
- Description: The aim of the research was to assess what competitive advantage a Removals company could expect to gain by outsourcing its driver function to owner drivers. An extensive literature review identified key outsourcing issues. The literature was related to a case study of Stuttaford Van Lines (SVL), a company that is experiencing problems with its current independent contractor driver arrangements and that needs to review its outsourcing decision. In order to learn from best practice in the field of outsourcing to owner drivers, a benchmarking exercise was undertaken at South African Breweries (SAB). The benchmarking exercise identified six key issues that contributed to the success of the SAB owner driver scheme. These points, together with others identified from the literature, were integrated into a recommended outsourcing implementation process for SVL. The research found that it is possible for SVL to outsource the driver function to owner drivers and that such a scheme can be expected to improve customer service levels. The success of the scheme will depend on the selection of the drivers and how effectively it is managed. It was found that it would not be profitable for SVL to outsource to owner drivers using the compensation model proposed. Cost reduction is however only one of the factors to consider in an outsourcing decision.
- Full Text:
- Date Issued: 2000
- Authors: Coleman, Belinda
- Date: 2000
- Subjects: Contracting out -- South Africa , Storage and removal trade -- Subcontracting -- South Africa , Trucking -- South Africa , Benchmarking (Management) -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11002 , http://hdl.handle.net/10948/d1015540
- Description: The aim of the research was to assess what competitive advantage a Removals company could expect to gain by outsourcing its driver function to owner drivers. An extensive literature review identified key outsourcing issues. The literature was related to a case study of Stuttaford Van Lines (SVL), a company that is experiencing problems with its current independent contractor driver arrangements and that needs to review its outsourcing decision. In order to learn from best practice in the field of outsourcing to owner drivers, a benchmarking exercise was undertaken at South African Breweries (SAB). The benchmarking exercise identified six key issues that contributed to the success of the SAB owner driver scheme. These points, together with others identified from the literature, were integrated into a recommended outsourcing implementation process for SVL. The research found that it is possible for SVL to outsource the driver function to owner drivers and that such a scheme can be expected to improve customer service levels. The success of the scheme will depend on the selection of the drivers and how effectively it is managed. It was found that it would not be profitable for SVL to outsource to owner drivers using the compensation model proposed. Cost reduction is however only one of the factors to consider in an outsourcing decision.
- Full Text:
- Date Issued: 2000
Possible crosstalk between signal transduction pathways in the induction of differentiation in HT-29 cells
- Authors: Jamie, Hajierah
- Date: 2000
- Subjects: Cellular signal transduction , Cell differentiation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11096 , http://hdl.handle.net/10948/d1019684
- Description: The investigation into the mechanisms by which compounds such as butyrate induce differentiation in HT-29 cells, is lacking. The colonic carcinoma cell line, HT-29, undergoes differentiation induction in the presence of butyrate and acetoacetate. The Caco-2 cell line spontaneously differentiates on contact inhibition. In this study, a signal transduction pathway involving ATP, cAMP, Ca2+ and the transcriptional factor CREB was investigated following suggestions that the energy state of the cell and diffferentiation are linked. The activity of the MAP kinase cascade, including possible crosstalk that may exist between these pathways was determined. The HT-29 cells were exposed to 5 mM acetoacetate, butyrate, DMSO and propionate. The results of this differentiation induction were compared to Caco-2 and HeLa cells, which are cervical carcinoma cells. It was found that ATP levels are decreased on differentiation induction in HT-29 cells, which, in turn affected the cAMP concentrations. Theoretically, the inducers do not have any effect on PDE 4 activity, and may facilitate the interaction between cAMP and PKA. Influx of Ca2+ into the cells was inhibited to a degree by the inducers, which was possibly overcome by crosstalk between the cAMP and Ca2+ pathways. CREB activation, lineage-specific gene expression, ERK activity and c-myc expression were all dependent on both the inducers used and the cell-type. PKA played a major role in CREB activation in acetoacetate- and butyrate -induced HT-29, Caco-2 and HeLa cells, while a2+/Calmodulin-dependent kinases I/IV may have a secondary role. Alkaline phosphatase expression in HeLa cells was independent of CREB. Evidence that crosstalk between the MAP kinase cascade and the REBactivation pathways exist, was illustrated by increased CREB activation on ERK inhibition in acetoacetate- and butyrate-induced HT-29 and HeLa cells. Also, the role that ERK played in the cells differed with inducer and cell-type. The dependence of cmyc expression on c-jun and c-fos, appeared to be differentiation induction- and celltype specific. Results from this study indicate the potential use of acetoacetate and butyrate as anti-cancer compounds.
- Full Text:
- Date Issued: 2000
- Authors: Jamie, Hajierah
- Date: 2000
- Subjects: Cellular signal transduction , Cell differentiation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11096 , http://hdl.handle.net/10948/d1019684
- Description: The investigation into the mechanisms by which compounds such as butyrate induce differentiation in HT-29 cells, is lacking. The colonic carcinoma cell line, HT-29, undergoes differentiation induction in the presence of butyrate and acetoacetate. The Caco-2 cell line spontaneously differentiates on contact inhibition. In this study, a signal transduction pathway involving ATP, cAMP, Ca2+ and the transcriptional factor CREB was investigated following suggestions that the energy state of the cell and diffferentiation are linked. The activity of the MAP kinase cascade, including possible crosstalk that may exist between these pathways was determined. The HT-29 cells were exposed to 5 mM acetoacetate, butyrate, DMSO and propionate. The results of this differentiation induction were compared to Caco-2 and HeLa cells, which are cervical carcinoma cells. It was found that ATP levels are decreased on differentiation induction in HT-29 cells, which, in turn affected the cAMP concentrations. Theoretically, the inducers do not have any effect on PDE 4 activity, and may facilitate the interaction between cAMP and PKA. Influx of Ca2+ into the cells was inhibited to a degree by the inducers, which was possibly overcome by crosstalk between the cAMP and Ca2+ pathways. CREB activation, lineage-specific gene expression, ERK activity and c-myc expression were all dependent on both the inducers used and the cell-type. PKA played a major role in CREB activation in acetoacetate- and butyrate -induced HT-29, Caco-2 and HeLa cells, while a2+/Calmodulin-dependent kinases I/IV may have a secondary role. Alkaline phosphatase expression in HeLa cells was independent of CREB. Evidence that crosstalk between the MAP kinase cascade and the REBactivation pathways exist, was illustrated by increased CREB activation on ERK inhibition in acetoacetate- and butyrate-induced HT-29 and HeLa cells. Also, the role that ERK played in the cells differed with inducer and cell-type. The dependence of cmyc expression on c-jun and c-fos, appeared to be differentiation induction- and celltype specific. Results from this study indicate the potential use of acetoacetate and butyrate as anti-cancer compounds.
- Full Text:
- Date Issued: 2000
The isolation and partial characterization of a2-antiplasmin and plasminogen from ostrich plasma
- Authors: Thomas, Adele René
- Date: 2000
- Subjects: Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11080 , http://hdl.handle.net/10948/274 , http://hdl.handle.net/10948/d1005751 , Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Description: This study reports the isolation, purification and partial characterisation of the ostrich serpin, a2AP, as well as its target enzyme, ostrich plasmin, in its active and inactive proenzyme, viz. plasminogen, forms. Three different procedures were undertaken to isolate and purify ostrich a2AP. The first one involved L-lysine-Sepharose chromatography, ammonium sulfate fractionation, ion-exchange chromatography on Toyopearl Super-Q 650S, and ostrich plasminogen-Sepharose affinity chromatography. The second procedure replaced the latter chromatographic step with gel filtration on Sephadex G-200 and hydroxylapatite chromatography, while the third one employed instead the theoretically more efficient LBSI-Sepharose chromatographic step. The third procedure yielded purified ostrich a2AP, but the degree of purity and yield were relatively low. Ostrich plasminogen was highly purified after L-lysine-Sepharose chromatography and ostrich plasmin was obtained by the urokinase-activation of the purified ostrich plasminogen Ostrich a2AP revealed an Mr of 77-84 K and two isoelectric forms of pI 3.85 and 6.18. Nterminal sequence analysis showed ostrich a2AP to have only 2 out of 11 residues in common with both those of human and bovine a2AP. Ostrich a2AP showed the largest inhibitory effects on ostrich plasmin, followed by comm. bovine chymotrypsin, trypsin and plasmin, in that order, and it appeared to be a much less potent plasmin inhibitor than bovine aprotinin, but a much more potent one than the synthetic inhibitors, DFP and EACA. Ostrich plasminogen showed an Mr of 92 K and multiple isoelectric forms (~7) in the pI range 6.01-9.18, with a major one of pI 6.01. It showed a total of 775 amino acid residues and its N-terminal sequence showed ~53 percent identity with those of human, rabbit, cat, and ox plasminogens. Ostrich plasmin revealed an Mr of 78 K, two isoelectric forms of pI 4.07 and 6.01, and a total of 638 amino acid residues. N-terminal sequence analysis showed that 2-4 residues are identical to the 5 of human, cat, dog, rabbit, and ox plasmins. The pH and temperature optima of ostrich plasmin were determined as 8.0 and 40 oC, respectively. The thermodynamic and kinetic parameters of ostrich plasmin were computed, and plasmin was shown to prefer Lys to Arg residues in the S1 position. In conclusion, ostrich a2AP, plasminogen and plasmin showed definite similarities to their mammalian counterparts, but there were also significant differences.
- Full Text:
- Date Issued: 2000
- Authors: Thomas, Adele René
- Date: 2000
- Subjects: Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11080 , http://hdl.handle.net/10948/274 , http://hdl.handle.net/10948/d1005751 , Serpins , Ostriches , Antifibrinolytic agents , Plasminogen , Plasmin
- Description: This study reports the isolation, purification and partial characterisation of the ostrich serpin, a2AP, as well as its target enzyme, ostrich plasmin, in its active and inactive proenzyme, viz. plasminogen, forms. Three different procedures were undertaken to isolate and purify ostrich a2AP. The first one involved L-lysine-Sepharose chromatography, ammonium sulfate fractionation, ion-exchange chromatography on Toyopearl Super-Q 650S, and ostrich plasminogen-Sepharose affinity chromatography. The second procedure replaced the latter chromatographic step with gel filtration on Sephadex G-200 and hydroxylapatite chromatography, while the third one employed instead the theoretically more efficient LBSI-Sepharose chromatographic step. The third procedure yielded purified ostrich a2AP, but the degree of purity and yield were relatively low. Ostrich plasminogen was highly purified after L-lysine-Sepharose chromatography and ostrich plasmin was obtained by the urokinase-activation of the purified ostrich plasminogen Ostrich a2AP revealed an Mr of 77-84 K and two isoelectric forms of pI 3.85 and 6.18. Nterminal sequence analysis showed ostrich a2AP to have only 2 out of 11 residues in common with both those of human and bovine a2AP. Ostrich a2AP showed the largest inhibitory effects on ostrich plasmin, followed by comm. bovine chymotrypsin, trypsin and plasmin, in that order, and it appeared to be a much less potent plasmin inhibitor than bovine aprotinin, but a much more potent one than the synthetic inhibitors, DFP and EACA. Ostrich plasminogen showed an Mr of 92 K and multiple isoelectric forms (~7) in the pI range 6.01-9.18, with a major one of pI 6.01. It showed a total of 775 amino acid residues and its N-terminal sequence showed ~53 percent identity with those of human, rabbit, cat, and ox plasminogens. Ostrich plasmin revealed an Mr of 78 K, two isoelectric forms of pI 4.07 and 6.01, and a total of 638 amino acid residues. N-terminal sequence analysis showed that 2-4 residues are identical to the 5 of human, cat, dog, rabbit, and ox plasmins. The pH and temperature optima of ostrich plasmin were determined as 8.0 and 40 oC, respectively. The thermodynamic and kinetic parameters of ostrich plasmin were computed, and plasmin was shown to prefer Lys to Arg residues in the S1 position. In conclusion, ostrich a2AP, plasminogen and plasmin showed definite similarities to their mammalian counterparts, but there were also significant differences.
- Full Text:
- Date Issued: 2000
Main thesis title: Onderwysers se belewing van multikulturele onderwys
- Authors: Strydom, Louise
- Date: 1999-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: Afrikaans
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60003 , vital:62732
- Description: The South African Schools’ Act of 1996 terminated segregated education in South Africa. Multi-cultural education has become a reality in the new democratic South Africa. As a result of this major shift in policy, the researcher probed for an answer to the following question: “How does the teacher, especially the teacher already in service, experience this new situation regarding multi-cultural education?” To find an answer to this question, a literature study and empirical research, making use of a representative sample of respondents in the Southern Cape, were undertaken. The researcher has personally experienced the challenges of having to adapt from a mono-cultural teaching environment to a multi-cultural teaching environment at school level, hence a further interest in this research problem. Relevant terminology was highlighted and a brief historical synopsis of the course that multi-cultural education took in Western societies such as the USA, Canada, Australia and Britain was studied. These sources were utilised to draw a comparison with the South African situation. A concise synopsis of the history of multi-cultural education in South Africa was also undertaken to highlight the complexity of the educational situation presently being experienced in South Africa. The empirical research, with a target group representing teachers in the Southern Cape, was undertaken by means of a self-compiled questionnaire to make an analysis of teachers’ attitudes, expectations and perceptions of multi-cultural education as experienced in the classroom. The information obtained from the respondents indicated a generally positive attitude towards multi-cultural education amongst teachers. A great need for in-service training also became evident. xvi The researcher has thus made recommendations regarding in-service training that she thinks is of utmost importance. The practical problems that were highlighted during the research, make a vital contribution towards the successful implementation of multi-cultural education in South Africa. , Thesis (DEd) -- Faculty of Education, 1999
- Full Text:
- Date Issued: 1999-04
- Authors: Strydom, Louise
- Date: 1999-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: Afrikaans
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/60003 , vital:62732
- Description: The South African Schools’ Act of 1996 terminated segregated education in South Africa. Multi-cultural education has become a reality in the new democratic South Africa. As a result of this major shift in policy, the researcher probed for an answer to the following question: “How does the teacher, especially the teacher already in service, experience this new situation regarding multi-cultural education?” To find an answer to this question, a literature study and empirical research, making use of a representative sample of respondents in the Southern Cape, were undertaken. The researcher has personally experienced the challenges of having to adapt from a mono-cultural teaching environment to a multi-cultural teaching environment at school level, hence a further interest in this research problem. Relevant terminology was highlighted and a brief historical synopsis of the course that multi-cultural education took in Western societies such as the USA, Canada, Australia and Britain was studied. These sources were utilised to draw a comparison with the South African situation. A concise synopsis of the history of multi-cultural education in South Africa was also undertaken to highlight the complexity of the educational situation presently being experienced in South Africa. The empirical research, with a target group representing teachers in the Southern Cape, was undertaken by means of a self-compiled questionnaire to make an analysis of teachers’ attitudes, expectations and perceptions of multi-cultural education as experienced in the classroom. The information obtained from the respondents indicated a generally positive attitude towards multi-cultural education amongst teachers. A great need for in-service training also became evident. xvi The researcher has thus made recommendations regarding in-service training that she thinks is of utmost importance. The practical problems that were highlighted during the research, make a vital contribution towards the successful implementation of multi-cultural education in South Africa. , Thesis (DEd) -- Faculty of Education, 1999
- Full Text:
- Date Issued: 1999-04
A logos of difference: the Kantian roots of Derrida's deconstructive thinking
- Authors: Hurst, Andrea Margaret
- Date: 1999
- Subjects: Derrida, Jacques -- Philosophy , Deconstruction , Philosophy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11003 , http://hdl.handle.net/10948/d1015554
- Description: This study concerns a contemporary articulation of the age-old limit/possibility (truth/scepticism) contest in Western metaphysics. Traditional `either/or' logic advises that scepticism is a necessary consequence of the assailability of truth; hence the concerted effort in the history of philosophy to preserve the possibility of truth against any flicker of uncertainty. Here, it is argued that contemporary thinking sees the possibility of `absolute' truth lose its ground. However, a concomitant shift to a `logos of difference' averts the consequence of scepticism. Thus, the justification for this study could be articulated in terms of the imperative, if a cardinal moment in contemporary thought is to be sustained, to understand this shift in logos, work through its implications and learn to live with its effects. In this respect, an attempt is made throughout to situate and interpret Derrida's `deconstructive thinking' as exemplar. Derrida's thinking finds roots (not without signs of insurrection) in Kant's `Copernican revolution,' construed as the first shift towards the contemporary logos in question. Here, Kant refuted the postulate of an independent `world' by demonstrating that `reality' was the result of a cognitive order imposed on what `exists' by the rational subject. Knowledge, therefore, depended not on matching statements with pre-existing `things,' but on knowing the `rules' that determined how an object had to be if it was to be known at all. Kant maintained that certain, objective knowledge was possible, due to the completeness and universality of the forms of intuition and the categories of the understanding. Kant's `Copernican revolution' provided the opening for a second shift inaugurated by the so- called `linguistic turn.' Here, thinkers contested what Kant took for granted; namely that `constitutive interpretations' (cognitions/concepts) formed a `reality' independently of language. The basic premise underpinning the `linguistic turn,' therefore, is that language (signification) and `reality' are inseparable. Henceforth, the possibility of final, enduring `constitutive interpretations' whose `truth,' in principle, is discoverable, depends on whether or not the language which mediates human rationality can form a complete and universal system. This question resurrects the very limit/possibility debate (in the form of a structuralism/postmodernism stand-off) that Kant thought he had resolved in mediating between rationalist and empiricist extremes. In contemporary terms, philosophers who, bound by either/or logic, wish to avoid the sceptical trap of `anything goes' postmodernism, must assume that language (signification) can form a complete and universal system. However, in his deconstructive readings of Husserl, Saussure and `structuralism,' Derrida demonstrates the untenability of this assumption. At the same time, he shows that the sceptical `alternative' may be avoided by recognising the limitations of `either/or' logic. Again, Derrida's thinking may be traced to Kant's; this time to his analysis of the `first antinomy.' In accordance with Kant's analysis here of what is ultimately the logic of `complex systems' (Cilliers), Derrida offers a `logos of difference,' which skirts the strictures of structuralism while avoiding the trap of postmodern scepticism by accommodating both moments of limit and possibility in an indissoluble interplay.
- Full Text:
- Date Issued: 1999
- Authors: Hurst, Andrea Margaret
- Date: 1999
- Subjects: Derrida, Jacques -- Philosophy , Deconstruction , Philosophy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11003 , http://hdl.handle.net/10948/d1015554
- Description: This study concerns a contemporary articulation of the age-old limit/possibility (truth/scepticism) contest in Western metaphysics. Traditional `either/or' logic advises that scepticism is a necessary consequence of the assailability of truth; hence the concerted effort in the history of philosophy to preserve the possibility of truth against any flicker of uncertainty. Here, it is argued that contemporary thinking sees the possibility of `absolute' truth lose its ground. However, a concomitant shift to a `logos of difference' averts the consequence of scepticism. Thus, the justification for this study could be articulated in terms of the imperative, if a cardinal moment in contemporary thought is to be sustained, to understand this shift in logos, work through its implications and learn to live with its effects. In this respect, an attempt is made throughout to situate and interpret Derrida's `deconstructive thinking' as exemplar. Derrida's thinking finds roots (not without signs of insurrection) in Kant's `Copernican revolution,' construed as the first shift towards the contemporary logos in question. Here, Kant refuted the postulate of an independent `world' by demonstrating that `reality' was the result of a cognitive order imposed on what `exists' by the rational subject. Knowledge, therefore, depended not on matching statements with pre-existing `things,' but on knowing the `rules' that determined how an object had to be if it was to be known at all. Kant maintained that certain, objective knowledge was possible, due to the completeness and universality of the forms of intuition and the categories of the understanding. Kant's `Copernican revolution' provided the opening for a second shift inaugurated by the so- called `linguistic turn.' Here, thinkers contested what Kant took for granted; namely that `constitutive interpretations' (cognitions/concepts) formed a `reality' independently of language. The basic premise underpinning the `linguistic turn,' therefore, is that language (signification) and `reality' are inseparable. Henceforth, the possibility of final, enduring `constitutive interpretations' whose `truth,' in principle, is discoverable, depends on whether or not the language which mediates human rationality can form a complete and universal system. This question resurrects the very limit/possibility debate (in the form of a structuralism/postmodernism stand-off) that Kant thought he had resolved in mediating between rationalist and empiricist extremes. In contemporary terms, philosophers who, bound by either/or logic, wish to avoid the sceptical trap of `anything goes' postmodernism, must assume that language (signification) can form a complete and universal system. However, in his deconstructive readings of Husserl, Saussure and `structuralism,' Derrida demonstrates the untenability of this assumption. At the same time, he shows that the sceptical `alternative' may be avoided by recognising the limitations of `either/or' logic. Again, Derrida's thinking may be traced to Kant's; this time to his analysis of the `first antinomy.' In accordance with Kant's analysis here of what is ultimately the logic of `complex systems' (Cilliers), Derrida offers a `logos of difference,' which skirts the strictures of structuralism while avoiding the trap of postmodern scepticism by accommodating both moments of limit and possibility in an indissoluble interplay.
- Full Text:
- Date Issued: 1999
Physiological and non-physiological induction of gastrointestinal differentiation
- Authors: Brauns, Seth Clint Aron
- Date: 1999
- Subjects: Gastrointestinal system -- Differentiation , Gastrointestinal system -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11089 , http://hdl.handle.net/10948/d1015521
- Description: The human colonic carcinoma cell lines HT-29 and Caco-2 both exhibit structural and functional differentiation under appropriate culture conditions. HT-29 can be induced to differentiate by treatment with short-chain fatty acids or acetoacetate. Caco-2 cells differentiate spontaneously upon contact inhibition. In this study HT-29 cells were treated with 5 mM acetate, propionate, butyrate and acetoacetate (physiological inducers) to assess their effects on the expression of carbonic anhydrase 1, sucrase-isomaltase and alkaline phosphatase which are reported to be markers of gastrointestinal differentiation. The maturation induction observed was compared to that of the spontaneous differentiation observed in Caco-2 cells. Assays were performed over an 18 day period. Results showed a close correlation (p < 0.05) between HT-29 and Caco-2 cell on days 4 and 12. These results indicate that differentiation reported in both cell lines is comparable and can be used as a basis for further comparative studies. In addition, parallel experiments to the above were conducted using a selection of nine rationally designed cyclic dipeptides (CDPs) potential drug entities which were chosen as non-physiological inducers. The results showed that the cyclic dipeptides were able to induce the gastrointestinal phenotype as observed in HT-29 cells treated with physiological inducers. Studies on the effects of energy-related metabolism in HT-29 and Caco-2 cells as induced by physiological and non-physiological inducers indicated that energy metabolism is a significant role player in gastrointestinal differentiation. The results reported show a decrease in ATP concentrations indicating that the cyclic dipeptides, like physiological inducers, affect the energy state of the HT-29 cells and thus may effect the differentiation of these cells. A positive correlation was found between histone phsophorylation and differentiation confirming that histone phsophorylation was partly responsible for the decrease in ATP concentrations. It is suggested that the induction of differentiation in HT- 29 cells could be either due to non-specific transcription of genes by activation of a chromatin switch or specific by the activation of signal transduction pathways based on the flux of ATP through the cells. Differential display RT-PCR is probably the most sensitive method that could be used to validate the suggestion of either a nonspecific transcription of genes or a specific differentiation reported for HT-29 cells.
- Full Text:
- Date Issued: 1999
- Authors: Brauns, Seth Clint Aron
- Date: 1999
- Subjects: Gastrointestinal system -- Differentiation , Gastrointestinal system -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11089 , http://hdl.handle.net/10948/d1015521
- Description: The human colonic carcinoma cell lines HT-29 and Caco-2 both exhibit structural and functional differentiation under appropriate culture conditions. HT-29 can be induced to differentiate by treatment with short-chain fatty acids or acetoacetate. Caco-2 cells differentiate spontaneously upon contact inhibition. In this study HT-29 cells were treated with 5 mM acetate, propionate, butyrate and acetoacetate (physiological inducers) to assess their effects on the expression of carbonic anhydrase 1, sucrase-isomaltase and alkaline phosphatase which are reported to be markers of gastrointestinal differentiation. The maturation induction observed was compared to that of the spontaneous differentiation observed in Caco-2 cells. Assays were performed over an 18 day period. Results showed a close correlation (p < 0.05) between HT-29 and Caco-2 cell on days 4 and 12. These results indicate that differentiation reported in both cell lines is comparable and can be used as a basis for further comparative studies. In addition, parallel experiments to the above were conducted using a selection of nine rationally designed cyclic dipeptides (CDPs) potential drug entities which were chosen as non-physiological inducers. The results showed that the cyclic dipeptides were able to induce the gastrointestinal phenotype as observed in HT-29 cells treated with physiological inducers. Studies on the effects of energy-related metabolism in HT-29 and Caco-2 cells as induced by physiological and non-physiological inducers indicated that energy metabolism is a significant role player in gastrointestinal differentiation. The results reported show a decrease in ATP concentrations indicating that the cyclic dipeptides, like physiological inducers, affect the energy state of the HT-29 cells and thus may effect the differentiation of these cells. A positive correlation was found between histone phsophorylation and differentiation confirming that histone phsophorylation was partly responsible for the decrease in ATP concentrations. It is suggested that the induction of differentiation in HT- 29 cells could be either due to non-specific transcription of genes by activation of a chromatin switch or specific by the activation of signal transduction pathways based on the flux of ATP through the cells. Differential display RT-PCR is probably the most sensitive method that could be used to validate the suggestion of either a nonspecific transcription of genes or a specific differentiation reported for HT-29 cells.
- Full Text:
- Date Issued: 1999
Aspects of the ecology and biology of Gilchristella aestuarius (G & T) (Pisces: Clupeidae) in the Swartkops estuary, Port Elizabeth
- Talbot, Marie Marcel Jean-Francois
- Authors: Talbot, Marie Marcel Jean-Francois
- Date: 1982-12
- Subjects: Fishes -- Ecology -- South Africa -- Swartkops River Estuary , Swartkops River Estuary (South Africa)
- Language: English
- Type: Master's theses , Manuscripct
- Identifier: http://hdl.handle.net/10948/52352 , vital:43613
- Description: The Department of Zoology at the University of Port Elizabeth has an ongoing programme on the Swartkops estuary with the eventual aim of drawing up the energy pathways of the system. Marais (1976) has investigated the nutritional ecology of the grunter Pommadasys cormersoni while Melville-Smith (1978) and Melville-Smith and Baird (1981) reported on the ecology of larval fish. Winter (1979) studied the ecological parameters of fish populations, but this work was not a detailed account of each population. Wooldridge (1979) studied components of the 3 zooplankton community in some detail. It became evident that there was a significant lack of understanding of the ecological relationships between plankton and piscivorous fish, which was crucial to the elucidation of the interactions and trophodynamics of the Swartkops estuarine system. Since G. aestuarius is an important link in the energy pathway from the plankton to the nekton, and in terms of numbers dominates the seine net catches made in the estuary (Winter, 1979), this study was motivated. The aim was to investigate the important biological parameters of the estuarine round herring population namely the population structure, distribution and abundance, individual growth rate from field data, the food and feeding habits, reproduction and respiration, all of which are essential for the understanding of the dynamics of a species. These parameters were later converted into energy terms and the construction of an energy budget was attempted. , Thesis (MSc) -- Faculty of Science, 1982
- Full Text:
- Date Issued: 1982-12
- Authors: Talbot, Marie Marcel Jean-Francois
- Date: 1982-12
- Subjects: Fishes -- Ecology -- South Africa -- Swartkops River Estuary , Swartkops River Estuary (South Africa)
- Language: English
- Type: Master's theses , Manuscripct
- Identifier: http://hdl.handle.net/10948/52352 , vital:43613
- Description: The Department of Zoology at the University of Port Elizabeth has an ongoing programme on the Swartkops estuary with the eventual aim of drawing up the energy pathways of the system. Marais (1976) has investigated the nutritional ecology of the grunter Pommadasys cormersoni while Melville-Smith (1978) and Melville-Smith and Baird (1981) reported on the ecology of larval fish. Winter (1979) studied the ecological parameters of fish populations, but this work was not a detailed account of each population. Wooldridge (1979) studied components of the 3 zooplankton community in some detail. It became evident that there was a significant lack of understanding of the ecological relationships between plankton and piscivorous fish, which was crucial to the elucidation of the interactions and trophodynamics of the Swartkops estuarine system. Since G. aestuarius is an important link in the energy pathway from the plankton to the nekton, and in terms of numbers dominates the seine net catches made in the estuary (Winter, 1979), this study was motivated. The aim was to investigate the important biological parameters of the estuarine round herring population namely the population structure, distribution and abundance, individual growth rate from field data, the food and feeding habits, reproduction and respiration, all of which are essential for the understanding of the dynamics of a species. These parameters were later converted into energy terms and the construction of an energy budget was attempted. , Thesis (MSc) -- Faculty of Science, 1982
- Full Text:
- Date Issued: 1982-12