C-type lectins in immunity : recent developments

Acknowledgements We thank the Wellcome Trust (Grant No. 102705) and Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology (Grant No. 97377) for funding. We apologise to our many colleagues whose recent work we were unable to cite due to space constraints.Peer reviewedPublisher PD

Investigating transmembrane TNF and transmembrane p55TNFR mediated signaling in host immune function during Mycobacterium tuberculosis infection

The importance of TNF-TNFR signaling in immunity against M. tuberculosis has been established. The aims of this study were to characterize the functions of membrane-bound TNF (Tm-TNF) and soluble TNF (solTNF) and to investigate the role of membrane-bound p55TNFR signaling as well as the in vivo significance of TNFR shedding in host immune responses during infection with M. tuberculosis H37Rv. To address this, mice expressing only the membrane-bound TNF or membrane-bound p55TNFR were exposed to a low dose of M. tuberculosis H37Rv by aerosol inhalation infection. The results presented in this dissertation illustrate that Tm-TNF mice were able to control acute M. tuberculosis infection but succumbed to chronic exposure to M. tuberculosis with pneumonia. We demonstrate that Tm-TNF mice displayed heightened pulmonary macrophage activation reflected by enhanced cell surface expression of MHC-II, CD80 and CD86 as well as enlargement of granulomas. Furthermore, our results show that solTNF has a regulatory function that modulates the magnitude of Th1 immune responses during acute and chronic stages of the infection. The evaluation of the functions of Tm-TNF and solTNF in host immune function in the presence of an established mycobacteria-specific immune response was carried out using a 'drug-based' M. tuberculosis reactivation model. Here, mice that were challenged with a low dose of M. tuberculosis were exposed to INH-RIF treatment for six weeks in drinking water, after which therapy was withdrawn and immune responses during reactivation were analyzed. Our results demonstrate that complete absence of TNF resulted in host susceptibility to recrudescence tuberculosis in the presence of a mycobacteria-specific immune response. TNF deficient mice were unable to suppress bacilli growth and formed diffused granulomas and succumbed early to reappearing tuberculosis compared to WT mice. By contrast, we show that Tm-TNF was sufficient for containment of reappearing mycobacterial growth and sustaining immune pressure in a manner comparable to WT control mice. xii Lastly, the analysis of host immune responses in mice expressing a non-sheddable p55TNFR revealed that persistent p55TNFR cell surface expression does not afford better protection to low dose M. tuberculosis infection. However, we observed a transient elevation in the frequency of pulmonary CD11b+/MHC-II+ cells in mice expressing a non-sheddable p55TNFR relative to WT mice as well as reduced cell surface expression of CD44 on CD4+ T cells. We also found that pulmonary IL-12p70 and TNF concentrations were elevated whereas IFNγ levels were reduced in mice expressing a non-sheddable p55TNFR relative to WT mice. Furthermore, data presented here describe the in vivo functional significance of p75TNFR shedding. We demonstrate using a double mutant mouse strain that in the absence of p75TNFR, mice expressing a non-sheddable p55TNFR display enhanced ability to control M. tuberculosis infection

Evaluation of potential oviposition deterrents for false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae)

There has been extensive research on the use of semiochemicals as deterrents or true repellents in insect pest management, particularly in push-pull strategies. Much of this research has focused on pests of medical and veterinary importance and has been limited for agricultural pests. This means there is an opportunity to study use of deterrents to manage pests of agricultural importance. No study has been conducted on deterrents for false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a key phytosanitary pest in citrus orchards across South Africa. This study assessed FCM oviposition deterrence in botanicals (plants (n = 11) and essential oils (n = 15)), and some commercial pesticides (n = 7) used for FCM control in South Africa. All tested botanicals were selected based on an extensive literature review of plant compounds that have been reported to deter or repel lepidopteran pests. Choice and no-choice oviposition bioassays were conducted in complete darkness in a controlled environment room. Oranges treated with solutions/suspensions of potential oviposition deterrents were placed into a cage with gravid FCM females for four hours, with oviposition being recorded every hour. Of the 33 tested compounds, only eight significantly reduced FCM oviposition (P < 0.05) compared to the control in oviposition bioassays i.e. two essential oils (lavender and peppermint), two plant crude extracts (garlic and marigold), one fruit (Mango), and three commercial FCM insecticides (Delegate, Coragen, and Warlock). All identified oviposition deterrents, except for Mango, were further investigated for their ovicidal properties in concentration response bioassays, where all botanicals were identified to have dual action (both deterrent and ovicidal properties), as they significantly (P < 0.05) reduced FCM oviposition and egg hatch. Garlic was the most efficacious botanical whilst Warlock was the only commercial insecticide that did not show ovicidal activity (F = 41.17, P = 0.0622). Larval penetration of the host fruit was less than egg hatch for all tested compounds in concentration response bioassays. Oviposition, egg hatch, and larval penetration were all affected by concentration, with the higher concentrations being the most effective. The efficacy of these deterrent compounds should be further tested in semi-field and/or field trials, and they may have potential in FCM management as allomone dispensers or sprays. They can also be implemented in push-pull strategies where they can be used in conjunction with FCM attractants. Lastly, repellence studies should be conducted in absentia of the host fruit to determine whether oviposition deterrence was a result of true repellence or odour masking.Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 202

Mourning and Melancholia in Zimbabwean Culture and Cinema

This thesis interrogates postcolonial melancholia and femininity through the textual analysis of literary and cinematographic works from Zimbabwe. The work is a transdisciplinary project encompassing psychosocial and postcolonial studies, as well as film and cultural studies. I define post-colonial melancholia in relation to how it has affected the postcolonial social sphere following the independence of Zimbabwe from British colonial rule in April 1980. I characterise melancholia as a loss of identity, ‘the missing object’/ lost object of affection that stemmed from colonial subjugation alongside the little remaining evidence of written Zimbabwean culture before colonialism. Today, there is a fragment of evidence that shows pre colonial Zimbabwean culture: it is forever lost. The colonial era is also relatively sparse regarding its cultural outputs, which is typical of any trauma that is ‘unrepresentable’. It is only recently that some films and plays have begun to address this head on. It is my argument that Zimbabwe is still in a state of melancholia, mourning the loss of her identity. I contend that the notion of identity is not straightforward, but rather is multifaceted and layered in trauma, tribalism, racism, class and sexism. There is, therefore, a need to reevaluate post-colonial theories in relation to post-colonial melancholia and find the correlation it has in forming a national identity. This thesis also explores the lack of female authorship in literature and film and what this tells us of the role of women in Zimbabwean society. I argue that the black female voice has been silenced through the ions of time and is only being regained very slowly. Thus autoethnography is used here as an anti -patriachal gesture, a resistance tool against the double interpellation black women endured/ are enduring in Zimbabwe. How can one account for postcolonial melancholia and what tools does a researcher deploy to examine it? This thesis adopts a psychoanalytical approach to account for the gaps and silences in Zimbabwean culture because of post-colonial trauma. I draw upon foundational Western scholars including Sigmund Freud, Jacques Lacan, Homi Bhabha, Louis Althusser and Frantz Fanon, and more recent thinkers such as Agnieszka Piotrowska, Stephen Frosh, Lauren Berlant and Ranjana Khanna. I also draw upon Zimbabwean writers Alois Mlambo, Dambudzo Marechera, Robert Muponde and, most notably, Tsitsi Dangarembga, P Mbatha, Panashe Chigumadzi, Yvonne Vera and other black female thinkers and writers. These writers and scholars aid in investigating how the postcolonial narrative is created and in unearthing the notion of identity and race relations in Zimbabwe, as well as who can take charge of this narrative, and the role of melancholia in framing this narrative. This argument is executed through textual analysis of prominent films and literature produced in Zimbabwe from 1940 to the present. The thesis offers a re-interpretation of postcolonial thinking through the lens of psychoanalysis, combining the textual analysis of film and literature alongside psychoanalysis and postcolonial theory. Finally, it interrogates the silences and gaps (the lack of films, literature and academic research) through interviews conducted with prominent individuals involved in the creative industries, set alongside the evocation of my personal experience as a Zimbabwean woman and academic. This is in line with the autobiographical genre used by many scholars, notably Frantz Fanon

Isolation of bioactive metabolites with activity against HIV-1 target proteins from extracts of Sutherlandia frutescens and Lobostemon trigonus

Acquired Immunodeficiency Syndrome (AIDS) is a human disease caused by the human immunodeficiency virus type 1 (HIV-1) and it is one of the biggest social, economic and health challenges in the world. The Joint United Nations Programme on HIV/AIDS (UNAIDS) and World Health Organization (WHO) estimated that between 33.4 to 46.0 million people around the world were living with HIV/AIDS in December 2005 and the highest estimates are in the Sub-Saharan Africa (around 25 million). In more developed countries a combined antiretroviral therapy called highly active antiretroviral therapy (HAART) is used, which results in reduced progression to AIDS in most patients. Despite the beneficial effects of HAART, significant side effects are experienced by treated patients. In addition, most infected people live in countries where the treatment is very expensive or, in many cases, not available at all. These people therefore rely on medicinal plants for health care. In this study, aqueous extracts from Sutherlandia frutescens and Lobostemon trigonus were screened for potential anti-HIV activities in a series of in vitro enzymatic assays, including reverse transcriptase, HIV-1 protease and glycohydrolases. Two extracts of Sutherlandia leaves (SFL-1 and SFL-2) were prepared that inhibited HIV reverse transcriptase and a Lobostemon leaf extract (LTL) was shown to also inhibit this enzyme. All extracts were assayed at 1.25mg/ml. Tannin content was determined for all active extracts using a tannic acid assay. SFL-1 and SFL-2 were found to contain about 6 percent and 7 percent tannins, respectively, and LTL contained 31% tannins by weight. Tannins were removed using polyamide columns and three fractions were collected for each. The extracts were also fractionated with Sephadex G-25, Amberlite IR 120 and Dowex 1-X8 as size exclusion, cation exchange and anion exchange, respectively. Extracts were also fractionated by preparative thin layer chromatography where two compounds were separated from S. frutescens extract with high activity against reverse transcriptase while showing insignificant inhibition towards other enzymes tested. SFL-BFW-10 and SFL-WEF-7 inhibited reverse transcriptase by almost 100 percent and the IC50 values calculated for these compounds were 0.34 and 0.23mg/ml, respectively. Cytotoxicity of these compounds was evaluated on Chang liver cells and peripheral blood mononuclear cells (PBMCs). None of these compounds showed any significant inhibition of cell proliferation. The purity of these compounds could not be confirmed because there was insufficient material to use in the techniques required to show purity and identification. Therefore, TLC was used to determine the nature of these compounds. SFL-BFW-10 was identified as an organic acid and SFL-WEF-7 was identified as flavonoid

Effects of colours, shapes and icons on performance and familiarity

Occupational injuries and illnesses remain to be a heavy burden on workers and employees in industrial developing and industrially developed societies, and health and safety in workplaces continues to be an important issue for ergonomists. Steps are being taken to stimulate health and safety agendas and to discover ways in which health and safety in industries can be improved. The main responsibility of employers is to provide employees with information, instructions and training that they required to carry out their work tasks in a healthy, practical and safe manner. The role of education as a countermeasure to occupational injury and illness is being re-examined by health and safety practitioners and safety training is being considered as a vital part of accident prevention strategies. Effective training programmes should guarantee that workers possess the skills they require to complete their tasks in a safe and healthy manner. Very little is known about the type and quality of training workers undergo and how that training affects the safety outcomes of companies. There has been an attempt over the past 20 years to increase the research on safety communications and a great deal of this research has been focused on safety warnings; with the greatest attention been placed on the components of safety signs, such as colours, size, shapes and icons. The effects of these components on comprehension with relation to age and education have not received the same amount of attention. The impact of familiarity on safety warnings with respect to age and education has also received very little attention; despite the knowledge that familiarity has been shown to increase the noticing of warnings and the comprehension of safety information. Despite the increase in the research on safety communication, the literature and research in South Africa is scarce. Studies present in South Africa do not encompass the comprehension of safety signs or the ability of individuals with different age and education levels to learn the information included in the signs. Due to the multi-linguistic nature of South Africa and the fact that South Africa is an Industrially Developing Country (IDC) with high levels of illiteracy, issues such as the comprehension of safety information must be addressed. Therefore, the objectives of this study were to investigate the effects of safety sign attributes on learning and familiarity, in subjects that differed in age and education levels. These effects were investigated through measuring the reaction and response times of the different subject groups, as well as the number of components in the safety signs that were recalled correctly. The combined results of these responses were used as a measure for familiarity. A set of signs was designed for the study by the researcher using three different colours, three different shapes, three different icons and text. Certain variables were omitted from some signs to create the test pool and the eight conditions that were tested in a laboratory setting. Each condition contained different components of the designed signs and 60 subjects were used to test these conditions. The subjects were placed in groups according to their age and level of education. Subjects were required to learn a set of 64 signs, either “With Occlusion” or “Without Occlusion”, and asked to recall the meanings of the components in the signs. Reaction time, response time and error rate were measured from the responses. The results showed that the conditions resulted in different reaction times, response times and error rates for all subjects. The signs containing a combination of shapes and text resulted in the best performance. Age and education were found to have a significant effect on various performance criteria as did the method in which the signs were displayed (Occlusion and No Occlusion). The increased repetitions and sessions elicited lower reaction times, response times and error rates. The conclusions drawn from this study suggest that different attributes be considered carefully when subjects are expected to learn and recall information in safety signs. The results also highlighted the need to increase the exposure of individuals to safety signs in order to increase familiarity and ultimately improve the recall and comprehension of the attributes

Perspectives of teachers on subject advisors as instructional leaders: a case study of two schools at Umbumbulu central circuit.

M. Ed. University of KwaZulu-Natal, Durban 2015.This was a study of two secondary schools and it was a case of perceptions of teachers on subject advisors as instructional leaders. To fulfil the purpose of the study, critical questions such as how teachers’ conceptualise the role of subject advisors in instructional leadership and what were teachers’ experiences of instructional support offered by subject advisors. To increase the validity of the findings and to ensure a cross-sectional representation of the various levels of classroom-based teachers, five participants (principal, two heads of department and grade 12 teachers) were purposively selected in each school. Qualitative data generation methods which were used were semi-structured interviews and document analysis. One of the most urgent agenda the government of South Africa seeks to deliver on, is quality education for all. In spite of the fact that since 1994, the government has been incrementally spending more on education than any other sector, there is little improvement in the quality of education. Research has established that district office-based officials are important role- players in supporting teachers to improve quality of teaching and learning, particularly during educational reform initiatives. It further states that differentiated and contextualised district office supports influences and shapes what teachers do in the classrooms. However, this study argues that there can never be a full understanding of what makes for effective teacher support without input from the teachers, who are the end-users of such support. Thus, it is important for professional development programme designers and subject advisors, in this case, to consider perspectives of teachers on what behaviours they think contribute to effective instructional support, for in the final analysis, teachers are the beneficiaries of such support. The findings of this study suggested that the participants believed that there are essential conditions that should prevail for successful professional development of teachers to occur. The converse was also found to be true in that the participants’ identified certain prevailing conditions which they believed sabotaged professional learning opportunities. It is thus important for the department of education to understand teachers’ views so that professional development programmes can be tailored to meet the needs of teachers

Mourning and melancholia in Zimbabwean culture and cinema

This thesis interrogates postcolonial melancholia and femininity through the textual analysis of literary and cinematographic works from Zimbabwe. The work is a transdisciplinary project encompassing psychosocial and postcolonial studies, as well as film and cultural studies. I define post-colonial melancholia in relation to how it has affected the postcolonial social sphere following the independence of Zimbabwe from British colonial rule in April 1980. I characterise melancholia as a loss of identity, ‘the missing object’/ lost object of affection that stemmed from colonial subjugation alongside the little remaining evidence of written Zimbabwean culture before colonialism. Today, there is a fragment of evidence that shows pre colonial Zimbabwean culture: it is forever lost. The colonial era is also relatively sparse regarding its cultural outputs, which is typical of any trauma that is ‘unrepresentable’. It is only recently that some films and plays have begun to address this head on. It is my argument that Zimbabwe is still in a state of melancholia, mourning the loss of her identity. I contend that the notion of identity is not straightforward, but rather is multifaceted and layered in trauma, tribalism, racism, class and sexism. There is, therefore, a need to re-evaluate post-colonial theories in relation to post-colonial melancholia and find the correlation it has in forming a national identity. This thesis also explores the lack of female authorship in literature and film and what this tells us of the role of women in Zimbabwean society. I argue that the black female voice has been silenced through the ions of time and is only being regained very slowly. Thus autoethnography is used here as an anti -patriachal gesture, a resistance tool against the double interpellation black women endured/ are enduring in Zimbabwe. How can one account for postcolonial melancholia and what tools does a researcher deploy to examine it? This thesis adopts a psychoanalytical approach to account for the gaps and silences in Zimbabwean culture because of post-colonial trauma. I draw upon foundational Western scholars including Sigmund Freud, Jacques Lacan, Homi Bhabha, Louis Althusser and Frantz Fanon, and more recent thinkers such as Agnieszka Piotrowska, Stephen Frosh, Lauren Berlant and Ranjana Khanna. I also draw upon Zimbabwean writers Alois Mlambo, Dambudzo Marechera, Robert Muponde and, most notably, Tsitsi Dangarembga, P Mbatha, Panashe Chigumadzi, Yvonne Vera and other black female thinkers and writers. These writers and scholars aid in investigating how the postcolonial narrative is created and in unearthing the notion of identity and race relations in Zimbabwe, as well as who can take charge of this narrative, and the role of melancholia in framing this narrative. This argument is executed through textual analysis of prominent films and literature produced in Zimbabwe from 1940 to the present. The thesis offers a re-interpretation of postcolonial thinking through the lens of psychoanalysis, combining the textual analysis of film and literature alongside psychoanalysis and postcolonial theory. Finally, it interrogates the silences and gaps (the lack of films, literature and academic research) through interviews conducted with prominent individuals involved in the creative industries, set alongside the evocation of my personal experience as a Zimbabwean woman and academic. This is in line with the autobiographical genre used by many scholars, notably Frantz Fanon

Using climate change interventions adopted by indigenous maize farmers as a strategy for developing primary school agriculture teachers’ competences for disaster risk reduction preparedness in Eswatini

This study investigated the role of local indigenous agricultural practices prevalent among Eswatini indigenous farmers in the Wet and Dry Middle-veld selected areas in disaster risk reduction preparedness for maize production. The study also explored the implications of integrating indigenous agricultural practices into the grade 6 and 7 primary school curriculum in Eswatini The study was qualitative in nature. Local farmers from four communities, two from Vusweni and Zombodze and the other two from Nhlambeni and Ngculwini areas in chiefdoms located in the Middle-veld participated in the study. In addition, individual qualified primary school’s agriculture teachers for grade 6 and 7, four (4) teachers located in the Dry Middle-veld primary schools and another four (4) in the Wet Middle-veld primary schools, participated in this study to provide an educational perspective into the research. Data was collected through administration of interviews, observations and artefacts (museum pictures). The participants were permanent residents in the Wet Middle Veld and the Dry Middle Veld. The individual face-to face interview sample consisted of four individual informants from each of the selected communities. In addition, four focus group discussions were also conducted in the same communities with five participants in each group for in-depth understanding of the studied phenomena. Thirty-two (32) participants were involved in the study in total. The transcribed individual interviews and focus group discussions were analysed through textual analysis approach. The findings of the study revealed that indigenous farmers used climate change adaptation interventions for Disaster Risk Reduction (DRR) preparedness. The indigenous agricultural practices adopted for DRR practices included household coping mechanisms such as soil moisture conservation, improvement of the soil nutrient status for enhanced food security by adding animal manure, intercropping, crop rotation, water harvesting, early planting, planting of legume crops, and fallowing. In addition, the observation and prediction of rain by interpreting the behaviour of plants and animals facilitated the operation of the indigenous farmers planting calendar. The above applied indigenous agricultural practices were still visible in the Middle-veld farming rural areas of Eswatini. The participating individual primary school’s agriculture teachers pointed out that agriculture teachers used some aspects of the indigenous agricultural practices to teach the primary school modern agriculture curriculum. Subsistence farming should remain a viable alternative to commercial farming for food security in Eswatini no matter how small their contribution was to average national annual agricultural production as it supported local indigenous farmers’ livelihoods.Science and Technology EducationM. Ed. (Environmental Education

STAT3 regulates proliferation and survival of CD8+ T cells : enhances effector responses to HSV-1 infection, and inhibits IL-10+ regulatory CD8+ T cells in autoimmune uveitis

Peer reviewedPublisher PD