11613 research outputs found
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The effect of oleic acid supplementation on lipid droplet production, betaoxidation and rotavirus replication
No full textDissertation (M.Sc.(Microbial and Biochemical))--University of the Free State, 2022Rotavirus (RV) is the most common cause of severe acute gastroenteritis in infants and young
children globally. Rotavirus infections induce cytoplasmic inclusion bodies called viroplasms
serving as a site of RV genome replication and assembly. Viroplasms recruit lipid droplets (LDs),
which play major roles in energy homeostasis and is a site for lipid storage. The successful
formation of viroplasm-LD complexes is essential for RV propagation. The extracellular supply of
oleic acid (OA, C18:1) to host cells induce LD biogenesis and modulate cellular fatty acid (FA)
metabolism. Rotavirus modulates the host cell lipidome and influence cell LD biogenesis and FA
metabolism by β-oxidation for successful viral propagation. Previous studies have shown that
chemical fragmentation of LDs by treatment with 3-isobutyl-1-methylxanthine (IBMX) and
isoproterenol (ISP) to be deleterious for RV infection. In addition, the chemical modulation of FA
β-oxidation by etomoxir (ETO) treatment has been shown to affect the propagation of other
viruses including hepatitis C virus (HCV). In this study, we sought to investigate (1) the effect of
OA supplementation on LDs during RV infection, (2) the effect of OA supplementation on FA β-
oxidation during RV infection and lastly, (3) the effect of LD and FA β-oxidation modulation on RV
infection. Briefly, HEK293 cells were supplemented with OA in the presence and absence of IBMX and ISP as well as ETO treatment during RV infection (MOI=5) for 6 h post infection (p.i). Control cells
were not treated with OA in the presence and absence of RV infection in which they were also
maintained in parallel with the test samples. At the end of each timepoint p.i, LDs where isolated
for triacylglyceride (TAG) quantification (LD quantification) while the test samples treated with the
same conditions were analyzed for changes in oxygen consumption rate (OCR) (FA β-oxidation
quantification) in HEK293 cells. For viral replication kinetics, HEK293 cells were again
supplemented with OA and treated with IBMX, ISP and ETO during RV infection as previously
describe for 0 h, 2 h, 6 h, 12 h and 16 h p.i, respectively. At the end of each time point, RV was
harvested and quantified using tissue culture infection doses 50 (TCID₅₀). Our study shows that supplementation of HEK293 cells with OA increase the overall TAG content
in isolated LDs, while the treatment of HEK293 cells with IBMX and ISP reduce TAG content of
isolated LDs. We further show an increase in total TAG content of isolated LDs when HEK293
cells are treated with ETO. Rotavirus infection increased the total TAG content of isolated LDs.
The supplementation of HEK293 cells with OA increased HEK293 cell OCR, while the treatment
with IBMX, ISP and ETO reduced the overall host cell OCR. Treatment of OA-supplemented HEK293 cells with IBMX, ISP and ETO slightly increased the overall OCR of the treated HEK293
cells compared to the OA unsupplemented HEK293 treated with the chemical inhibitors. It is also
important to note that RV infection reduced the overall OCR of HEK293 cells. Analysis of viral
kinetics showed that OA supplementation increases RV replication over time, while the treatment
of HEK293 cells with IBMX, ISP and ETO in the presence or absence of OA supplementation
reduce the overall replication of RV over time. The OA supplementation of RV infected HEK293
cells with IBMX and ISP rescues viral propagation over time, which was not observed when
HEK293 cells were treated with ETO. The data thus show that OA supplementation increases total TAG content in isolated LDs as well
as the overall host OCR while promoting RV infection over time. Rotavirus infection promotes
enrichment of LDs by increasing the overall TAG content of isolated LDs while reducing the overall
OCR of host cells. It was shown that the chemical modulation of both LD biogenesis and FA β-
oxidation is deleterious to RV propagation over time
Making and unmaking bonds: humanitarianism, local politics and peacebuilding in Southeastern Zimbabwe, 1988 to 1992
No full textFor a long time, perspectives of governments, civil societies and humanitarian organisations have overshadowed the voices of host communities during humanitarian emergencies. In a few instances where literature mentions host communities, they are often portrayed as homogenous groups that share similar views and attitudes towards those in need of assistance. In this article, I draw from host-refugee interactions to argue for the incorporation of local voices in civil society and humanitarianism studies and to illustrate the need to disaggregate host communities and pay attention to local politics during interventions. The influx of thousands of migrants from different countries and ethnic groups, changes the environment of the host community positively and negatively. Often, initial benevolence gives way to hostility as resource scarcities and insecurities arise. When this happens, it creates an environment of suspicion, blame, and stigma, which negatively impacts relations and cohesion between the two groups. Paying attention to local residents’ diverse perspectives during humanitarian emergencies may contribute to conflict prevention and peacebuilding.Publisher's versio
Cryptococcal protease(s) and the activation of SARS-CoV-2 spike (S) protein
No full textIn this contribution, we report on the possibility that cryptococcal protease(s) could activate
the SARS-CoV-2 spike (S) protein. The S protein is documented to have a unique four-amino-acid
sequence (underlined, SPRRAR|S) at the interface between the S1 and S2 sites, that serves as a
cleavage site for the human protease, furin. We compared the biochemical efficiency of cryptococcal
protease(s) and furin to mediate the proteolytic cleavage of the S1/S2 site in a fluorogenic peptide.
We show that cryptococcal protease(s) processes this site in a manner comparable to the efficiency of
furin (p > 0.581). We conclude the paper by discussing the impact of these findings in the context of a
SARS-CoV-2 disease manifesting while there is an underlying cryptococcal infection.Publisher's versio
The role of emotional intelligence and work engagement on nurses’ resilience in public hospitals
No full textOrientation: The ability to cope effectively with adversity has become vital for healthcare employees because of high job demands. Nurses are faced with workplace adversities that drain resilience resources; as such it is important to investigate factors that may conserve and build resilience resources. Positive states in the form of emotional intelligence and engagement have the potential to activate and conserve resources for coping and adaption amongst nurses.
Research purpose: The study was designed to investigate empirically the predictive value of emotional intelligence and work engagement on nurses’ resilience.
Motivation for the study: The study was motivated by the fact that negative experiences or adversities kindle loss of resources for coping and adaptive functioning. Promoting positive states has the potential to motivate the building of resources that improve coping and adaptation.
Research approach, design and method: The study utilised a cross-sectional quantitative survey using self-administered questionnaires. The sample comprised 252 nurses from the Mangaung Metropole, South Africa. The SmartPLS programme was used to analyse the data.
Main findings: Emotional intelligence and work engagement had a statistically significant effect on resilience. Of great significance was the strong direct link between emotional intelligence and resilience.
Practical or managerial implication: The healthcare sector needs to invest training in emotional intelligence and work engagement programmes for nurses as a way to improve their resilience; a coping strategy for the highly demanding and stressful work environments.
Contribution: These findings contribute valuable new knowledge that can be applied in promoting and enhancing resilience of nurses in public hospitals.Publisher's versio
Causes of the alarming rise of false sexual allegations against teachers in South African schools
No full textFalse sexual allegations against teachers have contributed to teachers leaving the profession early and a decline in males choosing the profession. The main focus of this study was to investigate learners' false allegations of sexual misconduct against teachers. This study was underpinned by Fabricated Rape Theory and adopted qualitative methodology data through semi-structured interviews. Four teachers, one deputy principal, and one principal making six participants in the South district of the Gauteng province of South Africa were selected using convenient selection methods. The collected data were analysed using the Thematic Analysis method, which enables the researcher to respond to the study's objectives one after the other. The study revealed that fear, emotional neglect, and revenge contribute to false sexual allegations against teachers and that the maintenance of professional conduct among teachers and policy change are the possible solutions. Therefore, the study recommends that students should be provided with adequate orientation and re-orientation about the implication of false allegations, that teachers should always maintain good conduct, and that there should be an improvement in school policies and code of conduct to include punishable consequences for false accusations.Publisher's versio
Expression of nutritional traits in vegetable cowpea grown under various South African agro-ecological conditions
No full textCowpea (Vigna unguiculata L.), a traditional legume food crop indigenous to Africa, has potential as both a vegetable and grain crop in contributing to dietary diversity to support health and address malnutrition, especially for those relying heavily on wheat, maize, and rice. The expression of nutritional traits (protein content and concentrations of iron (Fe), zinc (Zn), and manganese (Mn)) in cowpea leaves was evaluated over diverse agro-ecologies of South Africa and typical agronomic practices of smallholder farmers. The genotypes evaluated displayed genetic variation for all four traits. The mean values of Fe, Zn, Mn and protein content varied from 33.11 to 69.03 mg.100.g−1; 4.00 to 4.70 mg.100.g−1; and 14.40 to 19.63 mg.100.g−1 and 27.98 to 31.98%, respectively. The correlation analysis revealed significant degree of positive association between protein and Zn (r = 0.20), while negative associations were observed between Mn and protein (−0.46) and between Mn and Fe (r = −0.27). Furthermore, the expression of these important nutrient traits was influenced by the climatic conditions represented by six environments (location by year combinations) as is typical of ‘quality’ traits. Additionally, genotype-by-environment interaction effects were detected, suggesting that local soil properties and soil health may play a role in nutritional content in plants, perhaps particularly for legume crops that rely on symbiotic relationships with soil bacterial populations to fix nitrogen, which is crucial to protein formation. Further studies are needed to understand how to coordinate and align agronomic and soil management practices in vegetable cowpea production, especially those workable for the smallholder farmer, to realize the full genetic potential and nutritional value of improved vegetable cowpea varieties.Publisher's versio
Marine research and eco tourism centre: exploring notions of marine conservation, eco tourism, a social and educational intersect within the current temporal context
No full textDissertation (M.Arch. (Architecture))--University of the Free State, 2022Small rural coastal towns have unique shared experiences between humans and marine life The research question is How can a traditional Regional Coastal Vernacular form the social and educational Intersect, between industry (local fisherman and community) and oceanic life forms ( to support eco tourism in Struisbaai in the Overberg District Active. Active research in coastal Marine Protected Areas ( in the district is challenged with a lack of facilities to support the daily operations required for marine research, rehabilitation, and data collection. Traditional regional coastal (fig 01 industrial vernacular, study buildings and site context were investigated and synthesized to develop a symbiotic relationship into an architectural form to accommodate a Marine Research and Eco tourism Centre. Feedback from Marine Research experts and the fisherman community together with precedent study buildings established an interactive relevant symbiotic design. This dissertation provides solutions to address the marine conservation and eco tourism into a social and educational intersect to promote social cohesion and conservation in similar rural coastal communities
The photosynthetic efficiency and carbohydrates responses of six edamame (Glycine max. L. Merrill) cultivars under drought stress
No full textVegetable-type soybean, also known as edamame, was recently introduced to South Africa. However, there is lack of information on its responses to drought. The aim of this study was to investigate the photosynthetic efficiency and carbohydrates responses of six edamame cultivars under drought stress. Photosynthetic efficiency parameters, including chlorophyll fluorescence and stomatal conductance, were determined using non-invasive methods, while pigments were quantified spectrophotometrically. Non-structural carbohydrates were quantified using Megazyme kits. Structural carbohydrates were determined using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Drought stress significantly increased the Fv/Fm and PIabs of AGS429 and UVE17 at pod filling stage. Chlorophyll-a, which was most sensitive to drought, was significantly reduced in AGS429 and UVE17, but chlorophyll-b was relatively stable in all cultivars, except UVE17, which showed a significant decline at flowering stage. AGS354 and AGS429 also showed reduced chlorophyll-b at pod filling. UVE17 showed a significant reduction in carotenoid content and a substantial reduction in stomatal conductance during pod filling. Drought stress during pod filling resulted in a significant increase in the contents of trehalose, sucrose and starch, but glucose was decreased. Chlorophyll-a positively correlated with starch. The FTIR and XRD results suggest that the cell wall of UVE14, followed by UVE8 and AGS429, was the most intact during drought stress. It
was concluded that carotenoids, stomatal conductance, starch and hemicellulose could be used as physiological/biochemical indicators of drought tolerance in edamame. This information expands
our knowledge of the drought defense responses in edamame, and it is essential for the physiological
and biochemical screening of drought tolerance.Publisher's versio
Effective field immobilisation and capture of giraffe (Giraffa camelopardalis)
No full textOne of the highest occurrences of mortalities among giraffes (Giraffa camelopardalis) takes place during immobilisations, captures and translocations. Common mistakes, human error, unforeseen risks, the awkward anatomy and the sheer size of the animal are leading factors for giraffes’ mortalities during these operations. Many risks can be circumvented but some risks are unpreventable, often due to terrain characteristics (rivers, deep ditches, holes and rocky terrain). From 2011 to 2021, seventy-five giraffes were successfully immobilised and captured to collect biological and physiological data from eight different study areas across South Africa. A 0% mortality and injury rate was achieved and, therefore, the techniques described in this paper are testimony to the advances and improvements of capture techniques and drugs. Biological information and capture experiences were noted for 75 immobilised giraffes, of which, knockdown time data were recorded for 43 individuals. Effective and safe immobilisation requires a competent team, proper planning, skill and knowledge. In this manuscript, we address procedures, techniques, ethical compliance, welfare and safety of the study animals. General experiences and lessons learned are also shared and should benefit future captures and immobilisations by limiting the risks involved. The sharing of experiences and information could influence and improve critical assessments of different capture techniques and can likely contribute to the success rate of immobilisation and translocation success for giraffes in the future.Publisher's versio
Fire, herbivores, and vegetation type shape soil biochemistry in sodic patches of a semi-arid Savanna ecosystem
No full textIn the Kruger National Park (KNP), the lower slopes of catenas have open patches referred to as sodic patches. Fire and herbivores are dominant mediators of vegetation in sodic patches. The effect of fire and herbivores on soil properties of sodic patches remains largely understudied. Moreover, the co-existence of trees and grasses and how they influence savanna soils is an important but poorly understood phenomenon in ecology. Therefore, the present study aimed to determine the influence of 20 years of fire, herbivores, vegetation type, and their interaction on soil biochemistry of sodic patches on the Nkuhlu exclosures in the Kruger National Park, South Africa. We found a higher main effect of fire on available phosphorus, cation exchange capacity, and soil organic matter. The presence of herbivores caused an increase in soil exchangeable cations (K+, Ca2+, Na+, and Mg2+), organic matter, cation exchange capacity, and microbial activity. Tree canopies had a higher effect on total nitrogen, exchangeable Ca and Mg, soil organic matter, and cation exchange capacity than open grassland zones. Our results indicate that changes in vegetation structure due to fire and herbivores and their secondary impact on soil properties should be taken into consideration in managing savannas. Moreover, fire and herbivores play an important role in the maintenance of vegetation type (trees and grasses) in sodic patches.Publisher's versio