Biochemical characterisation of Pfj2, a Plasmodium falciparum heat shock protein 40 chaperone potentially involved in protein quality control in the endoplasmic reticulum
- Authors: Afolayan, Omolola Folasade
- Date: 2013
- Subjects: Plasmodium falciparum Endoplasmic reticulum Heat shock proteins Malaria , Mosquito-borne infectious disease
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3883 , http://hdl.handle.net/10962/d1001617
- Description: Plasmodium falciparum is a protozoan parasite that causes a severe form of malaria, a mosquito-borne infectious disease in humans. P. falciparum encodes a number of proteins to facilitate its life-cycle, including a type II heat shock protein 40 (Hsp40), Pfj2. Pfj2 shows a degree of homology to human ERdj5, a resident protein of the endoplasmic reticulum (ER) that promotes protein quality control by facilitating the degradation of misfolded proteins. The overall aim of this study was to further understand the function of Pfj2 in the P. falciparum cell by characterising it biochemically. A bioinformatic analysis of Pfj2 was carried out to enable the identification of a potential ER signal sequence and cleavage site. Furthermore, an analysis of Pfj2 protein sequence was performed to compare domain similarities and identities with typical type II Hsp40s namely, human ERdj5, S. cerevisiae Sis1, human Hsj1a and human DnaJB4. The method used included the insertion of the codon-optimised coding sequence for the processed ER form of Pfj2 into the prokaryotic expression vector, pQE30, to enable overproduction of a histidine-tagged protein. A 62 kDa His₆-Pfj2 was successfully expressed in Escherichia coli and purified using denaturing nickel affinity chromatography. ATPase assays were performed to determine the ability of His₆- Pfj2 to stimulate the chaperone activity of the ER Hsp70, also called immunoglobulin binding protein (BiP). Initial studies were conducted on readily available mammalian His₆-BiP as a control, which was shown to have an intrinsic activity of 12.07±3.92 nmolPi/min/mg. His₆- Pfj2 did not stimulate the ATPase activity of mammalian His₆-BiP, suggesting that it either could not act as a co-chaperone of mammalian His₆-BiP (specificity), or it required a misfolded substrate in the system. Therefore, ongoing studies are addressing the interaction of Pfj2 and misfolded substrates with P. falciparum BiP. The results of these studies will further our understanding of a poorly-studied parasite chaperone that represents a potential drug target for development of novel strategies for the control of a serious human disease
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- Date Issued: 2013
Evaluation and identification of critical success factors in the running of successful food security projects within the Eastern Cape Department of Rural Development and Agrarian Reform, in the Amahlhathi local municipality
- Authors: Tali, Patrick
- Date: 2013
- Subjects: Rural development -- South Africa -- Eastern Cape , Agriculture -- South Africa -- Eastern Cape , Project management -- South Africa -- Stutterheim , Food security -- South Africa -- Stutterheim , Food supply -- South Africa -- Stutterheim
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:836 , http://hdl.handle.net/10962/d1013346
- Description: The challenges of food insecurity and the manner in which it can be addressed is a global concern. Governments throughout the world have strived for means to address global food security either through development of Millennium Development Goals or United Nations protocols. It is a major concern that the South African Government has made it its centre focus to address the challenge of food security. In the Eastern Cape, the Department of Rural Development and Agrarian Reform has embarked on numerous food production programmes in an attempt to address this challenge. It is however noticeable that these attempts somehow did not manage to address their intended purpose. A study of literature with the aim of identifying critical success factors was done. The critical success factors identified and explored were, project management, establishing a clear mission and project objectives, addressing challenges and opportunities of social, environmental and economical sustainability, addressing physiological needs of the beneficiaries, involving the youth and community, role of extension services, training and capacity development, create local partnership and on-going monitoring and evaluation. The factors were then explored through a study of projects from the food production programme in Amahlathi Local Municipality in the Eastern Cape Province. A multiple case study wherein a purposive selection of four food security projects selected from two food security programmes was conducted. A structured questionnaire was used to source the information from all members of the selected projects to evaluate the existence of the critical factors. The main aim was to test whether these factors, if they existed in these projects, contributed to their existence. The findings reveal that none of the identified factors existed in the selected projects and though not proven, the non-existence of these factors has resulted in these projects being in survival mode instead of a sustainable state. A recommendation is made of a further study focusing on a bigger sample wherein these factors could be tested. The study could assist in developing a formal model for the running of these projects successfully.
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- Date Issued: 2013
Management of capital expenditure for infrastructure programmes in the North-West Province
- Authors: Norgbey, Wisdom Selorm
- Date: 2013
- Subjects: Construction industry -- Capital investments , Infrastructure (Economics) -- Management , Expenditures, Public
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9718 , http://hdl.handle.net/10948/d1021075
- Description: The need for programme management to align, coordinate and manage a portfolio of construction projects to deliver benefits that would not be achievable if the projects were managed independently in a turbulent economic environment, limitations of project management, and increasing stakeholder expectations cannot be over emphasised. In the construction industry, the implementation of programme management has been bedevilled with major challenges of which the North West Department of Public Works (DPW) CAPEX programme is no exception. The CAPEX programme has been noted for delivering fewer infrastructure projects as planned in terms of budget, time, and other expectations. The research documented in this treatise thus examined the existing programme management approach of the North West DPW CAPEX programme with respect to generally accepted standards and practices. A mixed research approach was used to identify problems such as delays in payment of works, poor reporting standards, improper planning of works, procurement difficulties, and inadequate management structures. The results point to excessive bureaucratic processes, improper information management systems and lack of commitment and ownership towards government works as the major underlying causes of the programme predicaments. Dogmatic implementation of government’s black economic empowerment policies and inadequate in-house capacity were also contributing factors. The research findings imply that effective processes should be laid for prompt payment of works certificates and invoices. Improved reporting standards and proper planning of the programme as a whole and its constituent projects is necessary for the attainment of stipulated goals. In particular, it is crucial to ensure that adequate management considerations in terms of capacity, infrastructure, structures and expertise are put in place while the procurement processes should be continually reviewed for programme success purposes.
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- Date Issued: 2013
Production of recombinant human CD21 and CD23 : towards a better understanding of their interaction
- Authors: Van Zyl, Dwain George
- Date: 2013
- Subjects: Immunoglobulins , Fc receptors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10365 , http://hdl.handle.net/10948/d10211135
- Description: The prevalence of allergic diseases has dramatically increased over the last three decades. Presently, it is estimated that 20-30 per cent of the developed world suffers from allergic diseases. The majority of allergic diseases are rooted in the activities of IgE; an immunoglobulin which exerts its effector functions by interacting with a network of proteins. This network includes its low affinity receptor CD23. Cross linking of membrane IgE and CD21 by soluble CD23 results in an increase in IgE synthesis. This marks the interaction between CD23 and CD21 as an attractive therapeutic target. However, details regarding this interaction are inadequate for rational drug design. To obtain a deeper understanding of the CD23-CD21 interaction recombinant human CD21 (SCR1-2 and SCR5-8) and CD23 (16 kD and 25 kDa) were produced. The cloning, expression and purification of recombinant proteins comprised a significant portion of this study. Recombinant CD23 was expressed as inclusion bodies, refolded by rapid dilution and purified by size exclusion chromatography. Conversely, recombinant CD21 was expressed as soluble MBP-fusions and purified with an amylose affinity resin. The interaction between recombinant CD23 and CD21 was analysed by flow cytometry and ELISA experiments. Flow cytometry showed that 16 kDa and 25 kDa CD23 interacted with SCR5-8 to the same extent. Semi-quantitative ELISA experiments showed that both SCR1-2 and SCR5-8 were able to interact with 16 kDa and 25 kDa CD23. This suggests that the binding sites of SCR1-2 and SCR5-8 occur on 16 kDa CD23. Furthermore, since proteins were expressed in E. coli it suggests that the CD23-CD21 interaction does not require glycosylation. Furthermore, considering what is known about the SCR1-2-CD23 interaction from previous NMR studies; i.e. that the C-terminal tail (residues residues 289-298) of CD23 is responsible for binding SCR1-2, indicates that SCR5-8 binds somewhere within the lectin domain of CD23. This indicates that the CD23-CD21 interaction involves C-terminal tail-SCR1-2 and lectin domain-SCR5-8 interactions.
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- Date Issued: 2013
Restitution : seeing past loss and abandonment
- Authors: Greenway, Paul Wayne
- Date: 2013
- Subjects: Digitally printed materials Bereavement in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2389 , http://hdl.handle.net/10962/d1001579
- Description: This dissertation is concerned with loss and abandonment, and together with the practical component, titled Restitution, forms part of a Master of Fine Art degree submission. Both loss and abandonment can take many forms, from the straightforward deterioration, departure or removal of objects to the more complex deterioration of memory, responsibility and dignity. It seems though, that the question, “What has been lost?” is one that is always asked once it is too late. The loss becomes irretrievable and one is left only with fragments and traces. In Chapter 1 issues of liminality and the precariousness of being between states is addressed. Dignity of the ‘other’, in this case the deceased pauper, is interrogated especially with reference to complicity, forensic investigation and the forensic aesthetic. Chapter 2 outlines photographic representation, with attention given to posthumous portraiture, the punctum and memory in the service of permanence and authenticity. Chapter 3 considers the ambition and purpose of the artist through a critique centred on contemporary photographic artist, Sally Mann. Throughout the thesis and exhibition, I am concerned with loss as it relates physically to objects. Metaphorically, I investigate loss and abandonment in relation to dignity and responsibility. In so doing I view death as being the ultimate form of loss, as there is physical loss of the body, as one part of the whole that makes up ‘the person’, as well as the psychological and emotional loss that attends the passing of life. The delayed burial of the deceased therefore is seen to be evidence of abandonment at its extreme. I end by positioning my conclusion around a stop animation series in which I dug a grave and buried a pauper at Mayfield cemetery.
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- Date Issued: 2013