Preliminary investigation of growth and antimicrobial production by streptomyces polyantibioticus : from shake flask to stirred tank bioreactor

Resistance to antibiotics by microbial pathogens continues to be a major global health problem. Treatment of bacterial infections is becoming increasingly complex and expensive. Tuberculosis (TB), caused by Mycobacterium tuberculosis infection, is affected by antibiotic resistance. In South Africa, the Western Province is the worst affected, with an increasing incidence of both multi-drug resistant (MDR) and extensively drug resistant (XDR) strains of M. tuberculosis. Both resistant forms of TB increase the length of treatment to almost 24 months and cost by as much as 1400 times that of regular anti-tubercular chemotherapy. A potential solution to this problem is the discovery of new drugs, which can be obtained from natural sources. Actinomycetes are good sources of these drugs, with over 45% of current medicines derived from these bacteria. The actinobacterium Streptomyces polyantibioticus SPRT (SPRT) was locally isolated and first described by Le Roes (2006). It has been shown to produce bioactive molecules active against a range of bacteria, including compounds (drugs) that have anti-tubercular properties. One of the anti-tubercular molecules was identified as 2,5-diphenyloxazole (DPO). DPO is currently used as a component of scintillation fluid for its luminescent properties and is synthesised chemically in industry. SPRT is the only reported biological source of DPO, it is however not yet produced commercially via a biological route. The present study was performed to inform future process development of DPO production from SPRT. An investigation into the growth and production of antimicrobial compounds from submerged cultures of SPRT in shake flasks, and scale-up of the process into a laboratory stirred tank bioreactor (STR) was done in the present study. The work focused on obtaining growth kinetics and suitable operating conditions for cultivation. Characterisation of the growth profile of SPRT and determination of the kinetic growth parameters was carried out. Additionally, the antimicrobial production phases, and factors influencing their production was investigated. It was determined that the most reliable method of measuring biomass concentration was by dry cell gravimetric measurement of whole shake flasks following vacuum filtration, as it best suited the non-homogenous filamentous nature of SPRT

The effects of hospitalization on the sleep patterns of patients aged 20- 30 years old admitted at a central hospital in Harare, Zimbabwe

A study of sleep deficiency patterns in patiens aged 20-30 hospitalized in a referral hospital in Zimbabwe.Sleep is a recurrent, altered state of consciousness that occurs for sustained periods, with restoration of energy and well being. Sleep also provides time for repair and recovery of body systems for the next period of wakefulness.'2 Most young adults sleep 6 to 8 hours a night and this can vary.3 In America at least forty million people suffer from over 70 sleep disorders when hospitalized, and 60 % of the adults report having sleep problems after hospitalization according to the National Sleep Foundation of America 1999-2004 Report.4 Factors that influence alteration of sleep include medication, pain, position in bed, diet, life style, cultural norms, fear of the unknown, environmental, personal and disease oriented factor.5 6 Various studies have shown that both quality and quantity of sleep to be less in hospital than at home. Sleep medications are often the interventions most frequently planned for sleep in hospitals

Inhibitory potential of honey on the enzymatic activity of Helicobacter pylori urease

Urease of Helicobacter pylori is an important virulence factor implicated in the pathogenesis of many clinical conditions, such as chronic gastritis, peptic ulceration, and gastric cancer. Many urease inhibitors have been discovered, like phosphorodiamidates, hydroxamic acid derivatives, and imidazoles. Despite good activities at the enzyme level and excellent kinetic properties most of them have not been used as therapeutic agents in vivo because of their side effects, toxicity and instability. This has led to much attention to focus on exploring the novel urease inhibitory activities of natural products because of their low toxicity and good bioavailability. Honey, a natural product has been used in folk medicine due to its antitumor, antioxidant, antimicrobial and anti-inflammatory properties. The aims of this study were to isolate, characterise, purify urease produced by H. pylori and investigate the inhibitory effects of solvent honey extracts on its enzymatic activity. Urease was found to be both surface-associated and cytoplasmic. Maximum cytoplasmic urease activity was found to occur after 72 hr whereas maximum extracellular urease activities were found to occur after 96 hr. Characterization of the crude cytoplasmic urease revealed optimal activity at a pH of 7.5 and temperature of 40°C. The kinetic parameters Vmax and Km were 45.32 U ml-1 and 61.11 mM respectively.The honey extracts inhibited the activity of the crude urease in a concentration dependent manner. The Lineweaver-Burk plots indicated a non-competitive type of inhibition against H. pylori urease. The two honey extracts gave promising inhibitory activities against urease of H. pylori. Thus the results of this study delineates that inhibition of urease can ease development in therapeutic and preventative approaches based on the enzymatic activity of this Helicobacter protein

An assessment of the effects of organisation change on employees : a case study of Chilanga cement plc, Ndola plant.

Thesis of Master of Business Administration (MBA).An assessment of the effects of organization change on employees at Chilanga Cement PLC, Ndola Plant sought to evaluate organization change within the establishment, examining different types of implemented change, the influence on employees and strategies for proficient change management. The research employed a Pragmatic philosophical approach by combining elements of both positivism and interpretivist. This study adopted a mixed-methods strategy, incorporating qualitative and quantitative methodologies for a sample size of 46 respondents. The study further triangulated data from different sources to provide a comprehensive examination. The findings regarding an assessment of the effect of organization change on employees at Chilanga Cement was facilitated by several research objectives among which was the examination of the different types of organization change implemented at Chilanga Cement. The overall impact of organization change on employees at Chilanga Cement indicates a 73.9% positivity rate, suggesting that organization change has an influence on Chilanga Cement employees. Among the organization changes implemented were restructuring, policy adjustments, cultural shifts, technological advancements, leadership transitions, product innovations, departmental transformations, and rebranding initiatives, illustrating the array of organization changes the institution has undergone over time. Furthermore, effective implementation of the change was observed at the Ndola plant. The study recommends that organizations, including Chilanga Cement, should formulate a comprehensive change management plan, ensure efficient communication and consistent updates on change program modifications, actively engage employees in all change processes, and address employee concerns during and after change implementation. The study further proposes future research on the study which includes longitudinal studies, psychological and behavioral perspectives, and leadership and change management practices

Conservation and use-values of medicinal plants in rural eastern Zimbabwe: A study of selected medicinal plants

Magister Artium (Development Studies) - MA(DVS)Medicinal plants remain a very important natural resource used as traditional medicines for health needs in many developing countries. In the current deepening economic and political crises in Zimbabwe a significant number of the population has inevitably relied more on natural resources which has led to receding population and scarcity of many medicinal plant species in their natural habitat. It is against this background that this research, using Rural Eastern Zimbabwe that this study explored the extent to which use values of medicinal plants increased since the Zimbabwean crises and the different use values of these species among men and women. The rational choice theory, use value approach and concept of utility constituted a theoretical grounding of the research process. The study essentially used qualitative research methods with some quantitative data. A mix of interviews and focus group discussions were employed for this study. Interviews were conducted with community leaders, traditional healers, NGOs in the similar field and Government stakeholders eliciting their views on use values of medicinal plants and sustainable interventions that can be enacted in conserving these species. The findings of the study were shown through using tables, charts and the quantitative data was presented using STATA. The calculated total usevalues of the 11 medicinal plants showed that Kirkia ancuminata Oliv, Dicoma anomala Sond, Syzgium guineense DC, Zingiber offinale, Acacia Karoo Hayne were found to have “high total use-values” and Lannea edulis Engl, Aloe, Lippia javanica Spreng, Virtex payos merril, parinari curatelli and Coleochloa setiflora have “low total use-values

A food systems approach to design a risk-based food control border framework for Zambia: a case study of Nakonde and Chirundu one-stop border posts (OSBP)

Thesis of Master of Science in Food Safety and Risk Analysis.This study investigates the effectiveness of food safety control systems at Zambia’s border posts, focusing on institutional capacities, infrastructure readiness, and inter-agency coordination. Against the backdrop of increasing regional trade under frameworks such as the AfCFTA, and persistent challenges in preventing foodborne hazards, this research provides a thematic analysis of systemic gaps compromising food safety governance at border points. Using a qualitative case study design, data were collected through key informant interviews with officials from regulatory agencies, supported by policy document reviews. Findings reveal four interlinked themes: (1) Human Resource Constraints, including severe staffing shortages and dual responsibilities, limiting oversight and responsiveness; (2) Infrastructure and Technology Gaps, such as the absence of dedicated sample transport, laboratory space, cargo scanners, and reliable internet connectivity; (3) Coordination and Information Exchange Deficits, particularly poor communication between border and inland teams and limited feedback mechanisms; and (4) Policy and Operational Inefficiencies, marked by fragmented mandates, lack of risk profiling, and minimal automation in back-office operations. The research highlights how these structural and functional weaknesses compromise Zambia’s compliance with international food safety norms and impede timely interventions at points of entry. The study concludes with a call for enhanced investment in border inspection infrastructure, institutional mandate alignment, targeted staffing reforms, and the adoption of integrated risk based frameworks. It recommends a coordinated national approach aligned with Codex principles and WTO SPS requirements to ensure effective food control and trade facilitation. The findings contribute to evidence-based policymaking for strengthening Zambia’s food safety systems within regional and global trade ecosystems

The role of chieftaincy in party politics in Africa: An analysis of the leadership succession systems of the South West Africa people’s organisation (SWAPO) and the Botswana Democratic party (BDP)

Magister Commercii - MComThis research analyses the influence of chieftaincy in party political processes in African states. In this regard, the study employs a case study design in investigating how chieftaincy shapes leadership succession dynamics within the South West African People’s Organisation (SWAPO) in Namibia and the Botswana Democratic Party (BDP) in Botswan

Learning about nurturant care of the Barotse floods of western province of Zambia.

ThesisThe background to this study had its genesis from the fact that little was known about indigenous nurturant care-based knowledge, values as well as competences and practices that have enabled the Lozi people of western Zambia to co-exist with floods over centuries and how such knowledge, values, competences could relate to environmental learning about aquatic ecosystem management. The study argues that nurturant care-based indigenous knowledge, values, competences and practices could provide learning opportunities for aquatic ecosystem management in rural areas or village landscapes better than modern techniques which primarily draw from the ‘hazard’ approach to floods. The study was guided by the following objectives: i) to determine indigenous nurturant care-based knowledge and values that have enabled the Lozi people to care for and co-exist with floods; ii) to establish indigenous competences and practices the Lozi people use to co-exist with floods; and iii) to examine the relevance of indigenous knowledge, values as well as practices to learning aquatic ecosystem management in contemporary society. The aim was to investigate indigenous nurturant care-based knowledge, values, competences and practices that enabled the Lozi people of Western Zambia to care for and co-exist with floods over centuries and how such could relate to learning about Aquatic Ecosystem Management. A case study was used in Lealui Ward area in the Barotse floodplains of Mongu District, Western Zambia. The sample consisted of thirty (30) drawn from the target population of twenty-four (24) indigenous Lozi adults’ respondents who live and utilizes the Barotse plains in Lealui, six (6) local leaders like village headmen and senior traditional leaders known as area indunas. Primary data was collected using semi-structured interviews, focus group discussions and observations. Secondary data was collected through analysis of documents. Data collected was analyzed thematically using hermeneutic narrative analysis (HNA). Within triangulation method was used to check on consistency and validate data. The study revealed that the benefits indigenous people derived from the flood plains was the reason they cared and value the Barotse plains for survival and continued existence. In addition, the study revealed that traditional knowledge among the Lozi adults was important in co-existence and adaptation to watery environment. The study findings showed that traditional knowledge is cardinal for society’s continued existence and adaptation strategies which enhance conservation and sustainable use of natural resources. The study findings also revealed that the practices included building settlements on mounds; construction of canals for drainage purpose, communication, irrigation and transport of goods; two type of residences in the floodplain and on the upper land; different types of gardens or fields. The study further revealed the competences which enabled the Lozi adults to co-exist with flood environment were paddling, swimming, blacksmith, repairing and boat building. Finally, the study findings revealed that indigenous nurturant care-based knowledge, values and practices are relevant in diversified production system, restraint in resource exploitation, conservation and sustainable use of natural resources and adaptation. The study concluded that floods are a source of happiness among the indigenous people of Barotseland of Western Zambia. Among the Lozi a good rain season is one that covers the entire floodplain. The people of Barotseland value the Barotse floodplain because of the many derived benefits. The following were the recommendations: to develop improved governance and regulatory models built on the strength of both traditional authority system and the national fisheries policy guidelines; government through the Ministry of Agriculture Food and Fisheries to supply irrigation equipments to farmers in Barotse floodplain to boost agriculture and enhance food security in the province and gazette Barotse floodplain as an Indigenous Peoples’ and Community Conserved Areas and Territories (ICCA) in Western Zambia. Key words: aquatic ecosystem management, floods, nurturant care, indigenous knowledg