Characterization of mycobacterial peptidoglycan remodelling enzymes

A dissertation submitted to the Faculty of Health Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Science in Medicine. May 2018.Mycobacterium tuberculosis (TB), the causative agent of tuberculosis, is responsible for over one million deaths per annum, a substantive proportion of these due to multidrug resistant or extensively drug resistant strains. The available antibiotics are rapidly becoming ineffective due to the development of resistance mechanisms by the pathogen. Considering this, there is an urgent need for novel and highly effective new TB drugs, with novel modes of action. The peptidogycan (PG) layer in the cell wall has emerged as a rich area for drug discovery. It undergoes constant reconstruction by penicillin binding proteins (PBPs) and other enzymes to allow for cell growth and division, while preventing lysis. In this study, we characterize the function of two Low Molecular Mass PBPs, known as D,D-carboxypeptidases (D,D-CPases, MSMEG_6113 and MSMEG_2433) in Mycobacterium smegmatis, a model organism for TB research. Using a bacterial two hybrid system, we demonstrate that MSMEG_2433 interacts with PonA1 (A High Molecular Mass PBP involved in PG synthesis) and FtsH (An AAA family protease and a member of the divisome complex). We also demonstrate that MSMEG_6113 forms a complex with FtsI (A High Molecular mass PBP and also part of the divisome complex) and a cell division control protein, Cdc48. We demonstrate that the two D,D-CPases associate with their partnering proteins via their C-terminal transpeptidase domain. The importance of these identified interactions for cell division and growth was tested through deletion of partnering proteins from the mycobacterial genome, particularly FtsI and Cdc48. FtsI is essential for mycobacterial growth in vitro as demonstrated by the inability to recover mutants through allelic exchange by homologous recombination, while Cdc48 is dispensable for growth. We noted morphological and cell division defects in the Cdc48 deletion mutant strain. The absence of Cdc48 results in bulging, kinking and chaining phenotypes, in addition to misplacement of the FtsZ ring. Collectively, our observations describe the presence of novel PG hydrolysing protein complexes that may mediate essential steps in PG synthesis and bacterial proliferation. Targeting these complexes may provide an attractive avenue for the development of novel TB therapeutics.LG201

Artificial intelligence for the improvement of records management activities at the Council for Scientific and Industrial Research

This study sought to investigate the usability of artificial intelligence (AI) for the improvement of records management activities at the Council for Scientific and Industrial Research (CSIR) in South Africa. Usability of AI and intelligent robotic machines for the management of records plays a crucial role in ensuring that records management activities are improved and managed effectively and efficiently. However, usability issues are critical in many AI systems, where human intelligence (HI) works with the system to work out and apply results (as with speech system). The convergent mixed methods research approach was applied and data were collected using interviews and questionnaires techniques. A questionnaire was administered to three professional repositories and indexers, two archives’ technicians and one data librarian. Interviews were conducted with one portfolio manager and one records manager. Data were analysed thematically and statistically and presented using tables and figures. AI has the capability to replace records practitioners since it can perform activities performed by records practitioners. This transition can have a negative impact on the usability of AI to improve the records management activities at the CSIR. The study revealed that AI and intelligent robotic machines can be used in the improvement of records management activities and can manage records effectively at the CSIR. The study proposed a framework on the usability of AI for the improvement of records management activities at the CSIR. It is hoped that the framework proposed will serve as a guideline on the usability of AI for the improvement of records management activities in the archives and records management sector

Pre-breeding of bottle gourd [Lagenaria siceraria (molina) standl.].

Doctor of Philosophy in Crop Science. University of KwaZulu-Natal, Pietermaritzburg 2016.Abstract available in PDF file

Response of dual-purpose cowpea landraces to water stress.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.Cowpea (Vigna unguiculata (L.) Walp) is an important protein-rich grain legume of major economic importance. It is widely grown by small-scale farmers in the arid and semi-arid regions of the world where it is cultivated for its leaves, fresh immature pods and dry grains. However, it is also an underutilized grain legume. In sub-Saharan Africa where most of the cowpea is produced, drought stress is one of the major factors limiting its productivity. Despite the inherent capacity to survive drought stress, several cowpea varieties are affected by mid and late season drought. Therefore, varieties with a higher tolerance to drought stress are required to obtain higher and more stable yields. The objectives of this study were: (i) to determine morphological responses of four dual-purpose cowpea landraces to water deficits during vegetative and reproductive stages (ii) to determine physiological responses of four dual-purpose cowpea landraces to water deficits and recovery during the reproductive stage (iii) to determine yield performance of cowpea landraces after recovery from water stress and how this relates to (ii) above. Four cowpea landraces namely; Lebudu, Lehlodi, Sejwaleng and Morathathane collectedfrom Kgohloane and Ga-Mphela villages, Limpopo Province, South Africa were used in the study. Pot experiments were conducted under glasshouse conditions at the Controlled Environment Facility (CEF), University of KwaZulu-Natal. The first pot experiment evaluated the morphological responses of four cowpea landraces to water stress and recovery. The study was conducted as a single factor experiment laid out in randomized complete block design (RCBD). The treatments (four cowpea landraces) were each planted in 40 pots giving a total of 160 experimental units (drained polyethylene pots with a 5 litre capacity). Each plant in each pot was treated as a replicate. Plants were well-watered until the formation of six fully expanded trifoliates, then irrigation was withheld for 28 days to simulate drought stress during the vegetative growth. The imposition of drought stress was terminated by re-watering all plants after 28 days. The cowpea plants were re-watered sufficiently and allowed to grow until the four landraces reached 50% flowering stage. Watering was withheld again at 50% flowering for a two-week period for all the four landraces to simulate drought stress during the reproductive growth. The second experiment was conducted to investigate physiological responses of the four cowpea landraces to water stress during the reproductive stage. The experiment was laid out as a 4 x 2 factorial treatment structure in randomized complete design (CRD) with the following three factors: cowpea landraces – 4 levels (Lebudu, Lehlodi, Sejwaleng and Morathathane), water regimes – 2 levels (stressed and well-watered) treatment combinations each replicated 20 times (20 pots each containing one plant) giving a total of 160 experimental units (drained polyethylene pots with a 5 litre capacity). Data on morphological responses were collected and included: number of green vs. senesced leaves, visual assessment of leaf greenness, stem, branch greenness and survival percentage. Physiological responses to water stress were determined during the reproductive stage and included: leaf water potential, relative water content, stomatal conductance, proline content, chlorophyll content, carotenoid content, chlorophyll a content, phenolics (free and membrane-bound), total antioxidant capacity and chlorophyll fluorescence parameters (Fv/Fm). Genstat 14th edition (VSN International, UK) was used to perform analyses of variance (ANOVA) and differences between means were determined by the Least Significant Differences (LSD) at the 5% probability level. Landraces showed different morphological responses during both vegetative and reproductive growth stages. Lebudu, Lehlodi and Sejwaleng displayed a strong ability to maintain stem greenness longer as compared to Morathathane during vegetative growth. Lebudu delayed leaf senescence more than other landraces; no differences in survival were observed. All landraces survived for 28 days without water and resumed growth after re-watering. During the reproductive stage, Lebudu displayed a strong ability to maintain leaf, branches and stem greenness longer and showed relatively higher tolerance to drought stress compared to other three landraces. Water stress caused a decline in leaf water potential, relative water content, carotenoid content, chlorophyll content, stomatal conductance and increased proline content, phenolics, chlorophyll a content, total antioxidant capacity and while chlorophyll fluorescence parameter, Fv/Fm, was not affected. All landraces maintained higher relative water content above a critical threshold with Sejwaleng maintaining a significantly higher RWC (69%) than Lehlodi, Lebudu and Morathathane. Morathathane developed a more negative leaf water potential at maximum stress than Lebudu, Lehlodi and Sejwaleng. Stomatal closure was observed in all cowpea landraces during water stress, but re-opened after re-watering. Chlorophyll content was considerably reduced in Morathathane as compared to Lebudu, Lehlodi and Sejwaleng. No significant differences were observed between the cowpea landraces with respect to carotenoid content at maximum stress. Chlorophyll a content increased significantly for Morathathane as compared to Lebudu, Lehlodi and Sejwaleng. High accumulation of proline was observed for Lebudu, Lehlodi and Morathathane as compared to Sejwaleng, which showed a very slow accumulation of proline. Lebudu, Lehlodi and Sejwaleng showed an increase in phenolic compounds while a decline was observed for Morathathane. Total antioxidant capacity (TAOC) was high in all cowpea landraces during water stress. Also, all chlorophyll fluorescence parameters showed that cowpea landraces had efficient photo-protection mechanisms during drought stress. After re-watering, relative water content, leaf water potential, stomatal conductance, chlorophyll content, carotenoids, chlorophyll a, proline content and TAOC recovered and reached the same level as that of well-watered plants. All four landraces were re-watered after the imposition of stress and above ground biomass, pod mass and number and seed yield determined. Although there was a reduction in the total above-ground biomass, pod mass and number in all four landraces under water stress compared to the well–watered treatment; this was not statistically significant (P > 0.05). Furthermore, no significant differences (P > 0.05) were observed between the four landraces with respect to seed yield under stressed and well-watered conditions. This study established that cowpea landraces vary with respect to the various morphological and physiological adaptive mechanisms in response to water deficits. Such adaptive mechanisms probably ensure their survival under severe water stress conditions until the next rainfall and therefore allowing them to produce reasonably relatively higher leaf and seed yield. Detailed knowledge of these mechanisms in the landraces could be useful in the genetic enhancement and breeding for drought tolerance in the existing cowpea germplasm

Selection of M5 mutant lines of wheat (Triticum aestivum L.) for agronomic traits and biomass allocation under drought stress and non-stressed conditions

IntroductionIn the face of climate changes and limited water availability for irrigated crop production, enhanced drought tolerance and adaptation is vital to improve wheat productivity. The objective of this study was to determine the responses of newly bred and advanced mutant lines of wheat based on agronomic traits and biomass allocation under drought-stressed and non-stressed environments for production and breeding.MethodsFifty-three mutant lines, including the parental check and six check varieties, were evaluated under non-stressed (NS) and drought stressed (DS) conditions in the field and controlled environments using a 20 x 3 alpha lattice design with two replicates. The following agronomic data were collected: days to 50% heading (DTH), days to maturity (DTM), plant height (PH), number of productive tillers (PTN), shoot biomass (SB), root biomass (RB), total biomass (TB), root: shoot ratio (RSR), spike length (SL), thousand seeds weight (TSW) and grain yield (GY). Data were analyzed and summarized using various statistical procedures and drought tolerance indices were computed based on grain yield under NS and DS conditions.ResultsSignificant (P < 0.05) differences were recorded among the mutant lines for most assessed traits under NS and DS conditions. Grain yield positively and significantly (p < 0.001) correlated with PTN (r = 0.85), RB (r = 0.75), SB (r = 0.80), SL (r =0.73), TB (r = 0.65), and TSW (r = 0.67) under DS condition. Principal component analysis revealed three components contributing to 78.55% and 77.21% of the total variability for the assessed agronomic traits under DS and NS conditions, respectively. The following traits: GY, RB, SB, and PTN explained most of the variation with high loading scores under DS condition. Geometric mean productivity (GMP), mean productivity (MP), harmonic mean (HM), and stress tolerance index (STI) were identified as the best drought tolerance indices for the identification of tolerant lines with positive correlations with GY under NS and DS conditions.DiscussionAmong the advanced lines tested, LMA16, LMA37, LMA47, LMA2, and LMA42 were selected as the superior lines with high performance and drought tolerance. The selected lines are recommended for multi-environment trails and release for production in water-limited environments in South Africa

Utilising artificial intelligence technology for the management of records at the Council for Scientific and Industrial Research in South Africa

Artificial intelligence technology is used in organisations to increase operational efficiencies and effectiveness. In a similar fashion, it can be used to manage records effectively and efficiently because artificial intelligence technology can perform records management activities quicker and faster than human intelligence. With the advent of artificial intelligence technology, records management practitioners should rather focus on planning effective strategies to develop records management programmes than on the activities that can be discharged through robotic machines. This study intended to address the current records management challenges which include system overload and crash. Artificial intelligence technology would ensure that records are managed effectively and efficiently. This study opted for a mixed methods research approach with a convergent design to investigate the utilisation of artificial intelligence technology for the management of records at the Council for Scientific and Industrial Research. The researcher opted to use a mixed methods research approach for this study because it cuts across multidisciplinary disciplines which can be effectively researched using a single approach. Records management theories, the technology acceptance model and the embedded system theory concepts were used to conceptualise the framework of the study. The sampled population of the study included one portfolio manager, one records manager, three professional repositories and indexers, two archives technicians and one data librarian. Data collection methods included focus group workshops, interviews, questionnaires, document analysis and observation. System analysis was used as a lens to review the current records management system. Quantitative data was presented in a descriptive way through tables and figures and qualitative data was presented through content analysis. The findings were integrated to ensure that the outcomes of the study were achieved. The findings revealed that records were not effectively managed because there was no reliable records management system. The Council for Scientific and Industrial Research used multiple systems and users did not know where to start when searching for records. However, this study advocated for the utilisation of artificial intelligence technology to manage records services effectively such as the automated digitisation, automated classification, and quick retrieval and disposal of records. The Council for Scientific and Industrial Research had no resources to utilise artificial intelligence technology to manage their records. A framework that would assist in adopting and utilising artificial intelligence technology for the management of records was recommended as a framework will provide guidance to the Council for Scientific and Industrial Research on how artificial intelligence technology could be effectively implemented to efficiently manage the records. The study adds value to the prevailing theoretical and conceptual phenomena that form the perpetual discourse on the application of artificial intelligence technology for the management of records. The study also adds value by recommending a framework to apply artificial intelligence technology in the records management industry at the Council for Scientific and Industrial Research. The researcher could not include other research institutions in South Africa due to time limitations. Other researchers can focus on exploring the study in other research institutions in South Africa.Information ScienceD. Litt. et Phil. (Information Science

Application of risk management processes in small and micro retail enterprises within the city of Tshwane Metropolitan Municipality, Gauteng: a case study

Small and micro retail enterprises share a competitive space with large retailers that are well resourced, have established brands and view risk management as a vital tool for business sustainability. The failure rate of small, medium and micro enterprises (SMMEs) is estimated to be between 70% and 80% (Adeniran and Johnston, 2011). Positioning in the shared competitive space has, therefore, become a challenge for many small and micro retail enterprises due to various obstacles and factors. In reality, the competitive space has contracted. As a result, what used to be a traditionally successful small business in the market space may not be relevant due to the global shift, emerging risks and customer perceptions of price, value and quality. The world is riskier and risks are inherent. This research study focused on how small and micro retail enterprises in the City of Tshwane Metropolitan Municipality (CTMM) effectively applied risk management processes to manage the obstacles and factors that cause failure. A qualitative research design, using a semi-structured interview tool and observations provided sufficient data on three small and micro retailers in the City of Tshwane (CoT) Central Business District (CBD). The study revealed that the small and micro retailers faced internal and external risks in the CoT. However, the risk management processes consisted of fragmented processes that were reactive, did not consider risks on the total enterprise level, did not conduct risk assessments, did not select appropriate risk responses and did not formulate business objectives. Moreover, the participants of the small and micro retailers lacked risk awareness, types of risk and risk management, and they had not attended training. As a result, they were not aware of the comprehensive benefits of managing risks in their enterprises. The study recommended that in order to improve their chances of survival, the small and micro retailers should implement risk management processes effectively.Graduate School of Business Leadership (SBL)M.B.A

The nutritive value of macadamia oil cake meal and wood ash as alternative feed ingredients for chickens in rural areas

The majority of South African household live in poverty with a limited variety of foods available in their home. In most rural villages domestic poultry plays an important role in improving household food security, but is limited by shortage of feed and high feed costs. Using non-conventional feed ingredients in poultry diets may ease the situation of malnutrition in rural populations, providing the family with high quality animal protein at more affordable prices. Macadamia oil cake meal (MOCM) is an inexpensive by-product from the macadamia oil industry of the Limpopo Province. Although it is relatively high in crude protein (20-25%), MOCM has never been considered as a feed ingredient for poultry feeds. The high and varying fibre content (up to 25%, depending on the extrusion method applied) of MOCM may render it unsuitable as an ingredient for high producing poultry such as broilers. The question, however, arouse whether the inclusion of MOCM in the growing diet of meat-producing chickens typically found in rural areas, would be cost-effective. Calcium (Ca) in poultry rations is usually supplied as calcium carbonate from limestone. Wood ash (WA) from fireplaces at homestead in rural villages was found to be rich in Ca (approximately 26%) and has the potential of being a free and readily available Ca supplement that could easily be added to the diet. The purpose of this study was to evaluate the effects of MOCM and WA as alternative feed ingredients in growth rations for chickens in rural areas. New Hampshire chickens were randomly divided into eight treatment groups with four replicates per treatment and twelve chicks in each replicates. The chicks were housed in an environmentally controlled broiler house from day-old to 15-weeks of age. Four diets were formulated, one without MOCM and the other three containing different levels of MOCM, viz. 10, 50 and 100% plus salt and a trace nutrient mixture. Each of these treatments was split in two with one receiving limestone (CaCO3) and the other WA, as Ca sources, giving eight treatments in total. All the treatments received diets with a Ca level close to 1 %. Parameters measured on weekly basis were body weight (BW), feed intake (FI), and body weight gain (BWG) and feed conversion efficiency (FCE) was determined. The analysis of the carcass composition and tibia bone strength was done at the end of the 15 week period. An analysis of variance with the ANOVA model (SAS) was used to determine the significance between different treatments for the balanced data. Significance of difference (5%) between means was determined by multiple comparisons using Tukey t-test. The treatment of 100% MOCM was terminated at eight weeks since the chickens had retarded growth and low body weight gains, demonstrating that the 100% MOCM diet both with and without Ca were not feasible. The BW and feed intake of the diet of 100% MOCM plus WA was, however,significantly higher than the diet of 100% MOCM plus lime. However, the inclusion level of up to 50% MOCM had no significant differences in (muscle and fat), except for FI, BWG and FCE between treatment diets. In conclusion, the results prove that MOCM can be added to the ration at a 10% concentration level without any adverse effect on growth. Higher inclusion levels of MOCM might also be beneficial,especially when included at an older age of the bird. Wood ash proved to be an efficient Ca source, as the substitution of limestone with WA showed no negative effect on the tibia bone parameters measured. CopyrightDissertation (MInstAgrar)--University of Pretoria, 2010.Animal and Wildlife Sciencesunrestricte

Changes in work and production organisation in the automotive industry value chain: an evaluation of the responses by labour in South Africa

ABSTRACT This research report examines the changing nature of the organisation of work and production methods in the South African automotive industry through an examination of the global production network of a leading automotive company, BMW. It draws on Marxist theory of the transformation of the labour process and extends this theory to include the contemporary restructuring of the automotive industry through the introduction of global production networks. It is argued that, while this logistical revolution has increased productivity, it has also opened up new sources of bargaining leverage for workers through the introduction of new production concepts such as Just In Time (JIT) and Just In Sequence (JIS). Through an analysis of the supply chain of BMW in South Africa and Germany the study demonstrates the contradictory nature of contemporary restructuring in the global automotive industry. The method used in the study involved in-depth interviews with key actors in the industry, a field research trip to the BMW Regensburg assembly plant in Germany, extensive consultation of union documentation and extensive participant observation in the process of restructuring in my capacity as head of Organising, Campaigns and Collective Bargaining (OCCB) in the National Union of Metalworkers of South Africa (NUMSA)

Political Accountability Dilemma: Another Pandemic Post Covid-19?

In view of the unceasing global pandemic, centralized governments across the world have been put under the spotlight to account for all the provisions in the states they represent. Early 2020, the COVID-19 pandemic has dispersed worldwide with many repercussions, such as economic lockdown, that gave rise in important decline of international economic activities and gave escalation in social insecurity. This has disproportionally affected lot of countries if not all, leading to their citizen’s incapability to pay and maintain their necessities such as housing and further disrupted public services by government. This has called on to the government to provide basic services reliably and effectively. The study seeks to elevate a discussion on the need to address political accountability as it appears to be a massive dilemma in government. The study argues that the pandemic has created a conducive environment for lack of political accountability. Moreover, as a matter of urgency, accountability in governance should be re-evaluated, where more decisive actions should be taken to avoid another pandemic post COVID-19. The study adopted desk research method, the researcher used secondary data such as published report, books, previous studies, journal articles and other readily available materials to gain broad understanding of accountability dynamics. The study takes cognisance of the stewardship approach to broaden an understanding of accountability and political leadership. As remedy, the study calls for enforcement of harsh accountability mechanisms to avoid another pandemic post COVID-19