Showing items 10381 - 10400 of 33287

Towards the development of a larval feeding strategy for the white-margined sole (Dagetichthys marginatus)

  • Authors: Thompson, Ernst Frederick
  • Date: 2014
  • Subjects: Flatfishes -- South Africa , Soleidae -- South Africa , Soleidae -- Larvae , Soleidae -- Larvae -- Feeding and feeds , Soleidae -- Larvae -- Physiology , Artemia
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5364 , http://hdl.handle.net/10962/d1012982
  • Description: The major bottleneck during the domestication of the white-margined sole Dagetichthys marginatus in South Africa has been low larval survival. The cause of this is not clear but considering current literature on flatfish culture and more specifically soleid culture, nutritional deficiencies are hypothesized to be the main possible cause. Following the importance of nutrition, the first aim of the research was to use an ontogenetic developmental approach to develop a species specific larval feeding strategy. Ontogenetic development of D. marginatus showed that weaning will take place at much later ages than other soleids currently being farmed. This makes the partial replacement of Artemia with a suitable inert diet in co-feeding strategies very important to cut the cost associated of live food production. This leads on to the second aim, in which an 'in vitro' approach was used to model the digestibility of Artemia, which could ultimately contribute towards designing inert feeds with similar digestibility characteristics to Artemia in the future. Obtaining nutrients from food is closely linked to the functional status of the digestive tract, the support organs and the external morphological characteristics required for the ingestion of live or inert feeds. Considering both morphological and physiological ontogenetic development, it is clear that D. marginatus follow a similar pattern to other soleids. Larvae can successfully feed on Artemia as early as 3 days after hatching but exhibit a slow metamorphosis into the juvenile stage when compared to other soleids. The absence of any detectable acidic protease activity during the first 45 days of development and the importance of exogenous enzymes from Artemia all points to limited capacity to digest artificial diets. Prior to modelling the 'in vitro' digestion of Artemia, digestive enzyme activity at different pH's were modelled using functional forms from the normal distributive category of functions. , As there is no substantiated information for the general effects of pH on enzyme activity in the literature for finfish larvae, three species occurring in the same bio-geographical region of Dagetichthys marginatus, namely Sarpa salpa, Diplodus sargus capensis and Argyrosomus japonicus were used to investigate this effect. The fitted parameters, namely the optimal pH and sigma (the slope around the optimal pH) showed two interesting results. When using a negative log likelihood ratio test to test for differences between species for a particular enzyme, the optimal pH for alkaline proteases (7.67), lipase (8.03), amylase (7.69) and phosphatase (9.84) activity was the same for all three species. Furthermore, the study illustrated the potential to detect dietary shifts during ontogenetic development based on changes in enzyme activity around the optimal pH using the sigma parameter. Sarpa salpa showed increased amylase activity and a decrease in protease activity around the optimal pH with increased size, corresponding to a change in diet from zooplankton to algae. The 'in vitro' modelling approach taken in this study was based on known enzyme interactions and dynamics which makes the results very interpretable. from Artemia is achieved based on gut evacuation time and enzyme levels. This 'in vitro' study furthermore clearly indicates the importance of exogenous enzymes from Artemia, contributing as much as 54 percent to protein digestion and 64 – 72 percent to carbohydrate digestion. This was however, only an initial investigation, and further expansion of the model is required to achieve a complete understanding of Artemia digestion and ultimately partial replacement with artificial diets. A feeding strategy for D. marginatus should therefore follow those of other farmed soleids, although there will be a general delay in implementation due to slower development. Problems can thus be solved and improvements made by transferring technology from other soleids to D. marginatus.
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  • Date Issued: 2014

Towards the feasibility of a landowner enterprise in the western Baviaanskloof : an external stakeholder analysis

  • Authors: Wiles, Kira Leigh Deborah
  • Date: 2014
  • Subjects: Landowners -- South Africa -- Eastern Cape , Natural resources -- Co-management -- South Africa -- Eastern Cape , Land use -- Environmental aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Eastern Cape , Partnership -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1198 , http://hdl.handle.net/10962/d1012075 , Landowners -- South Africa -- Eastern Cape , Natural resources -- Co-management -- South Africa -- Eastern Cape , Land use -- Environmental aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Eastern Cape , Partnership -- South Africa -- Eastern Cape
  • Description: In May 2012, a meeting was held between various stakeholder representatives of the Western Baviaanskloof to discuss the concept of a proposed landowner-enterprise. This concept was put forward in response to a need for collaboration in the midst of economic, environmental and social issues at play in the Baviaanskloof. Owing to the conservation value and rapidly decreasing economic output of the land, a radical shift to sustainable land-use practices was called for by various stakeholders. Suggested as a vehicle to generate income for the local landowners through alternative sustainable land-uses, the proposed enterprise may aid in addressing this shift by use of a bottom-up approach. During the stakeholder meeting, it was requested by the representative landowners that a feasibility assessment be conducted on the concept of the proposed enterprise prior to establishment. As an integral part of this assessment, the researcher took on the task of investigating stakeholder reception to the enterprise by means of a stakeholder analysis. It was decided to limit this to three markets: water, carbon and tourism. The purpose of this research study is twofold, namely to: investigate stakeholder influence and their reception of the proposed enterprise using a stakeholder analysis; and also to identify and advise on the opportunities and constraints relating to stakeholders, thus contributing to determining the feasibility of the proposed enterprise. In achieving the purpose of this study, a systematic stakeholder analysis framework was constructed, based on existing theory. This was necessary because, although stakeholder analysis is commonly practiced, no study was found to provide a theoretically based framework for the purpose of feasibility in the initial stages of enterprise establishment. Thus the contribution of the study is also twofold, namely the practical outcome of determining stakeholder reception for feasibility, and a secondary outcome of constructing a stakeholder analysis framework. The stakeholder analysis framework is based on an interpretation of existing stakeholder theory, with the addition of four "relational indicators" – goals, intentions, relationships, and resources. These four indicators provide a link between theory and practice in gauging the two attributes of stakeholder influence – power and interest. Dealing with a number of stakeholder interests in a unique context, the study takes on a single network case study approach in the paradigm of phenomenology. To suit the complex nature of the study, semi-structured interviews with various stakeholder representatives were conducted, using groups or organisations as units of analysis. Drawing from the stakeholder analysis framework and overall purpose of the study, four research objectives were set. The first was to identify the proposed enterprise's legitimate key external stakeholders, based on the three markets: water, carbon and tourism; the second to describe, categorise and assess relative dyadic influence of the above stakeholders by gauging their power and interest; the third, to determine the stakeholder network influence and probable reception of the proposed enterprise; and the last to advise the landowners on any identified opportunities or constraints stakeholders might pose, and thus to contribute to determining feasibility. In addressing the first objective, 21 stakeholders were identified, 12 of whom were found to be key to the current investigation. These key stakeholders were: Gamtoos Irrigation Board (GIB), LivingLands, R3G, Rhodes Restoration Group, Eastern Cape Parks and Tourism Agency (ECPTA), Department of Water Affairs (DWA), Nelson Mandela Bay Metropolitan (NMBM), Saaimanshoek, South African National Biodiversity Institute (SANBI), Department of Economic Development, Environmental Affairs and Tourism (DEDEAT), Baviaans Tourism, and Baviaans Municipality. In applying the stakeholder analysis framework, ECPTA was categorised as the definitive (most influential) stakeholder to the enterprise, and DEDEAT, SANBI (through Working for Wetlands), Baviaans Tourism, GIB, and NMBM were categorised as pivotal (influential and active). In discerning stakeholder interest in the proposed enterprise, a number of emerging themes were found to affect the projected interest and behaviour of stakeholders, apart from their specified goals. Emerging themes included: tunnel visioning, internal disparity, individual/personality clashes, and misaligned interests. In addition to this, in interpreting stakeholder interest, specific intentions or agendas that might affect the interest shown towards the proposed enterprise were also taken into account. Five predominant intentions of stakeholders were identified as: implementing a stewardship programme, establishing a tourism association, establishing a water users' association, social development, and "the big vision". Findings on the final objective revealed a number of perceived opportunities and constraints relative to the feasibility of the enterprise. Three prime opportunities were identified as: partnerships with definitive and pivotal stakeholders, the possibility of tendering for implementer of the "Working for" programmes, and taking on the role of Tourism Association. The following potential constraints were also emphasised by participants: social aspects such as individuals and personalities, the incompatibility or non-existence of local market structures, and the need for external funding. With regard to stakeholder reception, most of the stakeholders, with the exception of NMBM and Saaimanshoek, responded positively to the idea of the enterprise. Overall, based on participant perceptions, the tourism market was found to be the most feasible the carbon market uncertain and a long-term possibility, and the water market the least feasible.
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  • Date Issued: 2014

Towards the modeling of indigenous poultry production in the Eastern Cape Province, South Africa: characterization and extension evaluation for poverty reduction

  • Authors: Yusuf, Shehu Folaranmi Gbolahan Shehu
  • Date: 2014
  • Subjects: Poultry -- Breeding -- South Africa -- Eastern Cape , Chickens -- Breeding -- South Africa -- Eastern Cape , Economic development -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Doctoral , PhD (Agricultural Economics)
  • Identifier: vital:11223 , http://hdl.handle.net/10353/d1019833 , Poultry -- Breeding -- South Africa -- Eastern Cape , Chickens -- Breeding -- South Africa -- Eastern Cape , Economic development -- South Africa -- Eastern Cape
  • Description: Poverty remains a critical issue mostly in the rural South Africa. Various initiatives, policies and programs have been enacted by the government with attempting to reduce poverty at the national and provincial levels; poverty is yet to be abated. The target of the Millennium Development Goal 1 (MDG1) of halving poverty by the year 2015 notwithstanding, poverty remains a threat to quality livelihoods. Agriculture has continued to be one of the pillars of government efforts to address poverty. However, in livestock production interventions, efforts of government had largely been on cattle, sheep, goats, pigs and exotic poultry with little attention being given to indigenous poultry production (IPP). This study explores the option of using IPP to address rural poverty by capitalizing on its minimal inputs while recognizing its prevalence in a variety of households. The study addresses the characterization of the IPP from the perspectives of housing, feeding, healthcare management, breeding and marketing options.Skill competencies of the indigenous poultry farmers (IPFs) and the Agricultural Development Technicians (ADTs) were examined. This study reviewed poultry models in different parts of the world with special attention to Africa. The human resource development program of the department of rural development and agrarian reform was discussed. The study employed the use of multi-methods approach, the quantitative and qualitative research methodologies. Descriptive statistical analysis, frequent count, percentage, means, standard deviation, chisquare, and principal component analysis was used in the quantitative data analysis while the “open social system” was used for the qualitative methodology. Findings revealed that IPFs face some challenges among which are, the poor housing that exposed the birds to inclement weather, predator attacks and stock theft, high mortality of chicks after hatching and expensive feed for the flock. The IPFs showed competencies in nine skill items that included ability to identify chicken predators (x=3.92) and high yielding chickens (x=3.79); control of predators(x=3.77); methods of using ethno veterinary drugs to treat chicken diseases and pests (x=3.72), and identify signs of diseases (x=3.69), among others. However, the ADTs did not show any competency in any of the 32 skills items. The principal component analysis with Varimax rotation was performed to ascertain the dimensionality of the measures. Six factors with eigen value of >1, which accounted for 77.317% were extracted, with each factor loading ranging from 0.523 to 0.93. Factor loading after rotation that emerged on the same component was described; as brooding, shelter and care of the chicks; predators and healthcare; hygiene and litter management; feeds and feeding stuff; and record keeping and marketing. The findings on the human resource development revealed that staff meetings were the most common method of capacity development. This was followed by in-service-training, formal study, workshop, and on the job training. The farmers’ field school and study tours were sparingly used. However, respondents were in favor of on-site training, staff meetings, formal study and in-service training. The findings on the appropriate model suggest a theoretical indigenous poultry production model (IPPM) for the Eastern Cape Province (ECP). The “open social system” was used to develop a framework for an indigenous poultry cooperative society (to be known as Abafuyi Benkukhu Zemveli [ABZ]). This was meant to create a binding force for capacity development, a strong economic foundation through equity contributions, creation of marketing channels, and the development of a concept of ‘‘our own'' product in the market. Lastly, the study offers options for a training program that would accommodate the new initiatives, with a strong capacity development training approach. In this context, the study advocates for institutional support for the IPFs and the incorporation of indigenous poultry in the curriculum of the agricultural training programs at higher education institutions in South Africa.
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  • Date Issued: 2014

Towards understanding the effects of stocking density on farmed South African abalone, Haliotis Midae

  • Authors: Nicholson, Gareth Hurst
  • Date: 2014
  • Subjects: Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalones -- South Africa , Fish stocking -- South Africa , Abalone populations -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5371 , http://hdl.handle.net/10962/d1015646
  • Description: The profitability of abalone farms is heavily influenced by their production per unit of grow-out space. With farms having physically expanded to the maximum, and with increasing production costs, one of the most realistic ways for farms to increase their production is through optimizing stocking densities. The effect of stocking density on Haliotis midae performance is undocumented and optimal stocking densities for this species have not been determined. Experiments were conducted under farm conditions to investigate the effects of four different stocking densities (16 %, 20 %, 22 % and 24 % of available surface area) on growth, production and health of three different size classes of abalone (15-35 g, 45-65 g, and 70-90 g start weight). Each treatment was replicated four times and trials ran over a period of eight months with measurements being made at four month intervals. Abalone behaviour was observed during the trials in the experimental tanks. Weight gain per abalone decreased with an increase in density for all tested size classes (5.04 ± 0.18 to 2.38 ± 0.17; 5.35 ± 0.21 to 4.62 ± 0.29; 7.97 ± 0.37 to 6.53 ± 0.28 g.abalone-1.month-1 for the 15-35, 45-65 and 70-90 g classes respectively, with an increased density of 16 to 24 %). Individual weight gain of 15-35 g abalone was similar at stocking densities of 16 % and 20 % while weight gain of 45-65 g and 70-90 g abalone decreased when density was increased above 16 %. Biomass gain (kg.basket-1.month-1) was not affected by stocking density in the 15-35 g and 45-65 g size classes (1.29 ± 0.02 and 0.97 ± 0.02 kg.basket-1.month-1 respectively). However, the biomass gained by baskets stocked with 70-90 g abalone increased with stocking density (1.08 ± 0.02 to 1.33 ± 0.02 kg.basket-1.month-1) with an increased density of 16 to 24 %) and did not appear to plateau within the tested density range (16 to 24 %). Food conversion ratio did not differ significantly between densities across all size classes. Stocking density did not have a significant effect on abalone condition factor or health indices. The proportion of abalone above the level of the feeder plate increased with density (7.26 ± 1.33 to 16.44 ± 1.33 with an increased density of 16 to 24 %). As a proportion of abalone situated in the area of the basket, the same proportions were situated on the walls above the feeder plate and on the feeder plate itself irrespective of stocking density (p > 0.05). Higher proportions of animals had restricted access to feed at higher stocking densities (p = 0.03). The amount of formulated feed available on the feeder plate did not differ between stocking densities throughout the night (p = 0.19). Individual abalone spent more time above the feeder plate at higher stocking densities (p < 0.05). The percentage of time above the feeder plate, spent on the walls of the basket and on the feeding surface was not significantly different at densities of 20 %, 22 % and 24 % (p > 0.05) but abalone stocked at 16 % spent a greater percentage of time above the feeder plate on the feeding surface (83.99 ± 6.26 %) than on the basket walls (16.01 ± 6.26 %). Stocking density did not affect the positioning of abalone within a basket during the day or at night. Different size H. midae are affected differently by increases in stocking density in terms of growth performance. Findings from this research may be implemented into farm management strategies to best suit production goals, whether in terms of biomass production or individual weight gain. The fundamental mechanisms resulting in reduced growth at higher densities are not well understood, however results from behaviour observations suggest that competition for preferred attachment space and feed availability are contributing to decreased growth rates. With knowledge of abalone behaviour at different densities, innovative tank designs may be established in order to counter the reduction in growth at higher densities.
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  • Date Issued: 2014

Training of teachers in multigrade teaching: integration of vertical and horizontal knowledge in post -training

  • Authors: Ganqa, Ncumisa Hazel
  • Date: 2014
  • Subjects: Combination of grades -- Cross-cultural studies Teachers -- In-service training Teachers
  • Language: English
  • Type: Thesis , Doctoral , PhD (Education)
  • Identifier: http://hdl.handle.net/10353/6158 , vital:29496
  • Description: The purpose of this study was to examine the training and development of teachers in multi-grade teaching in selected Eastern Cape primary schools with a particular focus on the integration of vertical and horizontal knowledge in post-training. Multigrade teaching is the combining of learners of different grade levels in one classroom taught by one teacher. To gain better understanding of the construct of vertical and horizontal integration of knowledge within post-training environment, this qualitative case study design sampled eight teachers, four school principals and three trainers, purposively. In order to evaluate the training and development provided for teachers in multi-grade classrooms the researcher examined the training programmes, the training curriculum and transfer of training inputs. The results of the study indicate that post-training is the determinant of the extent of the effectiveness of the transfer of training skills, knowledge and attitudes gained in multi-grade teaching training. The study found a massive gap that currently exists between training in multi-grade teaching and the actual transferability of such training in multi-grade contexts. Positive transfer of training in multi-grade teaching strategies was found to be skills related to teaching strategies, lesson management, curriculum integration and social components of multi-grade teaching. Negative transfer of training included classroom organisation, lesson planning, timetabling, curriculum adaptation and assessment. Although multi-grade teacher training programme is assumed to change behaviours, attitudes, impart knowledge and improve teaching skills, the results of the study indicate that training inputs might not necessarily transform into classroom practice. In order to facilitate and ensure vertical and horizontal integration of knowledge and skills and transfer of training to classroombased teaching, recurrent training in multi-grade teaching is therefore, suggested.
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  • Date Issued: 2014

Trends in the fish assemblage structure of two South African transition-zone estuaries : can these trends be linked to climate change?

  • Authors: Midgley, Craig
  • Date: 2014
  • Subjects: Estuarine fishes -- South Africa -- Climatic factors , Fish communities -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5368 , http://hdl.handle.net/10962/d1013173
  • Description: Changes in the fish communities of the Breede and Mbashe estuaries were investigated in relation to the environmental variables that influence the fish assemblages in these systems. The Breede Estuary (34° 24’21.6”S, 20° 51’ 08.2”E) occurs within the warm-temperate/cool-temperate transition-zone, while the Mbashe Estuary (32o 14' 55.4"S, 28o 54' 03.7"E) falls within the subtropical/warm-temperate transition-zone along the South African coastline. The Breede Estuary was sampled (seine and gill nets) during summer (January-March) over a period of 10 years (2002-2012), while the Mbashe Estuary was sampled (seine net) during spring (October) over a period of three years (2010-2012). The proportion of tropical fish species was higher in the Mbashe Estuary compared to the Breede Estuary, while the Breede Estuary contained a higher proportion of temperate species than the Mbashe Estuary. Although the abundance of individual species in both estuaries varied, the ranking of species in the Breede Estuary was stable over the 10 year period. Multivariate analysis showed that the fish communities within each reach (upper, middle, lower) of the Breede Estuary remained similar, regardless of year. In contrast, species composition in the Mbashe Estuary differed significantly between years mainly due to differences in the river flow regime during the study period. Environmental variables responsible for structuring the fish assemblage in each estuary differed. Salinity significantly impacted the spatial fish assemblage structure of the Breede Estuary, with most of the species recorded being associated with the more saline lower reaches. The abundance of tropical species near their distributional limit in the Breede Estuary appeared to be impacted by sea surface temperature (SST) as peak total abundance of these species coincided with the warmest SST, while the lowest total abundance coincided with the coldest annual SST during the study period. The fish assemblage structure in the Mbashe Estuary was impacted by differing freshwater input prior to sampling, with flooding negatively impacting the mean total abundance, species composition and diversity in this system. The variables that influenced the fish assemblage structure of both transition-zone estuaries will be affected by climate change in the future. These variables will, in turn, determine the composition, abundance and diversity of species within these important estuarine systems. In order to measure these impacts with any degree of understanding, long-term studies on the abiotic and biotic (including the ichthyofauna) features of these estuaries are required to interpret climate change trends.
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  • Date Issued: 2014

Trends in the TD-DFT calculations of porphyrin and phthalocyanine analogs

  • Authors: Mack, John , Stone, Justin , Nyokong, Tebello
  • Date: 2014
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/193882 , vital:45402 , xlink:href="https://doi.org/10.1142/S108842461450045X"
  • Description: In 2005, Kobayashi and coworkers reported trends in the TD-DFT spectra of 17 Zn (II) porphyrinoids [J. Am. Chem. Soc. 2005; 127: 17697] that were analyzed using Michl's perimeter model as part of a study of the anomalous magnetic circular dichroism (MCD) spectroscopy of zinc tetraphenyltetraacenaphthoporphyrin. In recent years, it has become increasingly clear that TD-DFT calculations with the commonly used hybrid B3LYP exchange-correlation functional of the Gaussian software package are problematic in the B-band region of porphyrinoid spectra, since the degree of configurational interaction between the B and higher energy ππ* state appears to be significantly overestimated. The CAM-B3LYP functional is now often preferred for analyzing the optical properties of porphyrinoids, since it includes a long-range correction of the exchange potential, which incorporates an increasing fraction of Hartree–Fock (HF) exchange as the interelectronic separation increases, making it better suited for studying compounds where there is significant charge transfer in the electronic excited states. The trends in the TD-DFT calculations are reexamined with a wider range porphyrinoid compounds including several with pyrazino moieties and are found to provide a closer agreement with the experimental in the B-band region for complexes such as zinc tetraphenylporphyrin and phthalocyanine.
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  • Date Issued: 2014

Triggering physics lecturers' reflections on the instructional affordance of their use of representations: a design-based study

  • Authors: Lombard, Elsa Helena
  • Date: 2014
  • Subjects: Physics -- Study and teaching , Physics -- Research
  • Language: English
  • Type: Thesis , Doctoral , DPhil
  • Identifier: http://hdl.handle.net/10948/2899 , vital:20361
  • Description: There is growing awareness in the physics education research community about the importance of using representations in physics teaching and the need for lecturers to reflect on their practice. This research study adopted a design-based research approach in an attempt to design a reliable, valid and practically useful artefact (framework/strategy) that could be used to trigger introductory physics lecturers’ reflections on their instructional use of representations. The artefact, which was instantiated with physics lecturers, comprised an observation protocol, an accompanying definitions key, a communication platform, and an instrument to assess the outcome (the levels of reflection). The video-data of lecturer practice were analysed using a priori codes to generate profiles of teaching practice. The resulting profiles were used to trigger individual video-stimulated reflection. The levels of reflection were assessed using a purpose-designed ‘Expectations of Reflection’ taxonomy. Thereafter a set of design guidelines and design principles were generated to guide further similar design-based educational studies. The process was validated via interview data but, while it was deemed a valid and reliable solution to the research problem, there were varying levels of perceived value of the artefact among the participating lecturers.
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  • Date Issued: 2014

Trophic relationships of hake (Merluccius capensis Castelnau, 1851 and M. paradoxus Franca 1960) from the Northern Benguela current ecosystem (Namibia) : inferences from stable isotopes and fatty acids

  • Authors: Iitembu, Johannes Angala
  • Date: 2014
  • Subjects: Hake -- Benguela Current , Merlucciidae -- Benguela Current , Multitrophic interactions (Ecology) , Food chains (Ecology) , Biotic communities -- Benguela Current , Merlucciidae -- Food , Fishery management -- Namibia , Stable isotopes , Fatty acids
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5944 , http://hdl.handle.net/10962/d1020296
  • Description: Two species of hake (Merluccius capensis and Merluccius paradoxus) account for most of Namibia’s fisheries catch, and they are important secondary consumers in the Benguela Current ecosystem. Inferences on their trophic relationships have been based mainly on stomach content analyses. However, such data are limited temporally because they represent only snapshots of recent feeding, and are quantitatively biased because of variation in the digestion rates of different prey. The principal aim of the thesis was to understand the trophic relationships of two hake species relative to each other, their known prey and top predators (demersal sharks) in the northern Benguela Current ecosystem (Namibia), using time-integrating trophic biomarkers. By using stable isotope (carbon and nitrogen) and fatty acid signatures of their muscle tissues, my overall objectives were to produce new knowledge about 1) hake ontogenic trophic relationships, 2) the contributions of different prey to hake diets, 3) hake dietary differences, and 4) some aspects of hake’s trophic relationships with demersal sharks. Tissues of hake (n=358), their potential prey (n=455), and demersal sharks (n=42) were collected between 2008 and 2012 during demersal bottom trawl surveys off Namibia, for stable isotope and fatty acid analyses. And more...
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  • Date Issued: 2014

Turning the lens on the adolescent suicide

  • Authors: De Monk, Ingrid Venessia
  • Date: 2014
  • Subjects: Teenagers -- Suicidal behavior South Africa -- Port Elizabeth , School children -- Mental health services -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:9582 , http://hdl.handle.net/10948/d1020791
  • Description: In South Africa, suicidal behaviour in the younger generations has become rapidly part of a major public health problem. It is a well-known fact that adolescence is a critical period of progression in a teenager’s development which makes them more susceptible and vulnerable to suicide. Statistics have shown that there has been an increase in suicide among adolescents within the last decade (Schlebusch, 2005). The main aim of this research study is to explore the perceptions of adolescents regarding the factors that contribute to adolescent suicide. This study reviews literature concerning various risks factors for adolescent suicidality. It also described major social and psychological theories of suicide and the extent to which these studies support the importance to adolescent suicide. In the literature review theories of Bronfenbrenner’s Ecological Systems Theory, Durkheim’s sociological theory of suicide, Freud’s psychological perspective and Baumeister’s Escape Theory were discussed. A qualitative research design will be used by using visual participatory methodology techniques namely photo voice and reflective writing. A sample of 12 grade 11 learners, male and female, was purposely selected to participate in the research study. The focus of the study is to investigate the risk factors underlying adolescent suicidal behaviour in schools in the Northern Areas of Port Elizabeth, as well as to explore the stressors experienced by adolescents that could contribute to them having a higher suicide risk. Another focus point will be to look at prevention strategies as an antipode for suicidal behaviour. The main findings that emerged from the data analysis include contributing factors namely: socio-economic factors, personal factors, psychological factors and educational and school-related factors. The main prevention strategy themes emerged from findings derived from the data and include: parental involvement, religion, professional help and support groups and confiding in someone that you trust.
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  • Date Issued: 2014

Uitdagings tot skooldissipline, die rol van waardes en karakteropvoeding by sekere hoërskole in Port Elizabeth

  • Authors: Swartz, Jan
  • Date: 2014
  • Subjects: School discipline -- South Africa -- Port Elizabeth , School management and organization -- South Africa -- Port Elizabeth , High school students -- South Africa -- Port Elizabeth -- Discipline
  • Language: Afrikaans
  • Type: Thesis , Masters , MEd
  • Identifier: vital:9590 , http://hdl.handle.net/10948/d1021081
  • Description: This study is aimed at determining the challenges relevant to discipline in schools, the causes for these challenges, the role of values in connection with discipline and the intervention methods and strategies that could solve these challenges. Communities, societies, governmental and non-governmental organizations all over the world are value-driven. The challenges in relation to discipline that currently exist in schools, could be seen as coming from societies. There are general attacks on “common sense” and “common values”. It seems that low academic achievements can be linked to moral degeneration and the only solution is moral education. In the light thereof, discipline has to do with order and behavior that is acceptable. We have therefore tried to establish what the challenges in relation to high schools are, and whether the values that have been taught and modeled contribute towards the quality of being disciplined and how the challenges to discipline are being addressed. Character education is highly rated because it helps with prevention of discipline problems and contributes towards a positive environment that promotes a positive attitude. Many teachers in South-Africa experience challenges to discipline in the classroom environment brought about by many factors. Despite the challenges there is little support from the relevant governmental departments. After the abolishment of corporal punishment which used to work as the most effective method, no alternatives were provided. Educators have to lean on their own reactive methods to manage attitude problems in class. It also seems that educators are not trained by the Department of Education to implement the newer discipline strategies. Teachers apply discipline based on their own personal teaching philosophies that seems right and acceptable to them. The study tries to establish which intervention strategies could best address the challenges in schools. The study follows a mixed (qualitative and quantitative) approach which uses an embedded design. The embedded design consists of a primary method that leads the research project. In this instance the primary method is qualitative while the secondary data are quantitative which plays a supporting role. The secondary methods which are quantitative are not prioritized but it is embedded. The datacollecting instruments which have been used for this study are questionnaires, focus group and personal interviews, The primary goal of this study is to determine what the main challenges are in South Africa that result in discipline are being challenged, being threatened and pressurised. To achieve the main goal it is necessary that the researcher determines through literature study how the term “discipline” has been historically understood, interpreted and managed, as there was a shift in emphasis on how the term “discipline” was understood 30 years ago compared to today. The researcher has done a complete literature study to determine what current, relevant literature sees as current challenges in relation to discipline and what has been done to solve it. The researcher gathers information through data-collecting to determine which challenges currently exist at schools. Research has been done on current solutions and intervention methods to determine if there are intervention methods that can deal with these challenges more effectively. The study also tried to research new intervention methods. The empirical study and also the literature study acknowledge that challenges according to discipline exists, that there are a link between discipline and values, that the teaching of values positively influences school communities and that intervention methods and techniques that exists are not effective
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  • Date Issued: 2014

Ukuzotywa kwabalinganiswa ngokwesithako sobunzululwazi bume-ngqondo kwiincwadi zedrama ezikhethiweyo zesiXhosa, ngokweemeko zale mihla

  • Authors: Bilatyi, Katy Nomthandazo
  • Date: 2014
  • Subjects: Xhosa drama Characters and characteristics in literature
  • Language: Xhosa
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10948/9913 , vital:26632
  • Description: Olu phando luza kugxila kuphononongo lobume bengqondo ephazamisekileyo yabalinganiswa, lujonga kananjalo izimo zabalinganiswa ngakumbi abatsha, indlela abacinga nabenza ngayo izinto. Olu phando luza kuphicotha obu bume bengqondo baba balinganiswa kusetyenziswa iincwadi zedrama ezilandelayo: uBuzani Kubawo, kaTamsanqa, uAmaza, kaQangule, uLiseza kutshona kaMbobo, u-Uthembisa noMakhaya kaMtywaku, Isikhwakhwa noBessie kaMtywaku kunye noNdiyekeni kaJongilanga. Olu thotho lweencwadi zedrama zikhethiweyo luza kusetyenziswa kwakhona ukubhentsisa ubungqondo-lukhuni lwababhali ekuzobeni abalinganiswa abatsha njengoongantweni nolwamvila lolu zobo kwindlela ulutsha oluziphethe ngayo. Olu phando lutshayelelwe ngesahluko sokuqala esiqulathe iingxaki zophando, iinjongo zophando, ukubaluleka kolu phando, okusele kubhaliwe ngophando olu, nalapho olu luza kwahluka khona. Isahluko sesibini sibonisa isithako sobuNzululwazi bume- ngqondo nezinye ezikhaphayo ezifana nenkcubeko apho kujongwa ukuba ingaba inkcubeko ayisetyenziswa na ngendlela ebangela ukuba abalinganiswa abatsha bazibone bekwimo emandla yoxinzelelo. Esi sithako senkcubeko sihambelana neso semo yokuziphatha apha kujongwa ukuba ingaba ukuziphatha kwaba balinganiswa batsha akuqhutywa yindlela uluntu olubabona ngayo bephenjelelwa nayindlela abazotywa ngayo ngababhali. Ezinye izithako ezikhapha esi sobume bengqondo seso sobudala apho kugxilwa kwindlela abajongelwa phantsi ngayo ngenxa yeminyaka yabo luluntu nabazali abaphela bebathathela izigqibo ezikhokelela kuxinzelelo nokuziphatha okungekuhle. Esokugqibela seso seOnomastiki apho kujongwa ukuba ingaba indlela abathiywe ngayo abalinganiswa ayinagalelo kusini na kwindlela oluziphethe ngayo ulutsha. Iimeko zoxinzelelo abazibhaqa bephantsi kwazo abatsha azibangelwa ngamagama abawanikiweyo na nekuye kulindeleke ukuba bawalandele ngenkani nokuba imeko ayivumi. Isahluko sesiThathu sakugxila kwizimo zabalinganiswa ze esesiNe sigxile kubalinganiswa nezigulo zengqondo.
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  • Date Issued: 2014

Understanding and modelling of surface and groundwater interactions

  • Authors: Tanner, Jane Louise
  • Date: 2014
  • Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
  • Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
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  • Date Issued: 2014

Understanding change and implications of divisional management model (DMM ) in a merged multi- campus University in South Africa

  • Authors: Mantashe, Lunga Xolisa
  • Date: 2014
  • Subjects: Organizational change
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10353/6103 , vital:29491
  • Description: The study sought to understand change and transition in a multi-merged campus university in South Africa. Specifically the objectives were to understand the Human Resource (HR) plan, how it is being rolled out, the reactions of workers to it, the effects of the plan on workers and the processes put in place to mitigate, rather than aggravate, the current and foreseeable consequences of the Human Resource plan. A qualitative case study was used and focus groups and semi-structured interviews (triangulated with observation and document analysis) were used on a purposive sample of unions and the university HR official in one campus. The researcher found that there is no organogram which acts as a framework wherein all workers in respective campuses shall fit in. additionally, there is no staff transition plan and harmonisation of conditions of service policy that is agreed upon. Though it seemed there were some mechanisms to attenuate the effects of the HR plan (possible retrenchments, loss of morale, uncertainty, stress, doubt and the like) such as voluntary service package, there were areas of concern about the lack of a properly and widely circulated plan, and the absence of plans to transition staff throughout the process of change. Consequently, the researcher recommended at the end of the study that there must be a change management leadership in each campus to drive transition, a creation of proper communication networks, institution of campus indabas, a design of a transition plan, harmonisation approaches, migration of institutional items to an institutional site and the facilitation of recognition agreements for those unions which are still recognise in the premerger manner.
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  • Date Issued: 2014

Understanding development aid and state autonomy : the case of European Union budget support to Mozambique

  • Authors: Ndlovu, Ana Admiração
  • Date: 2014
  • Subjects: Economic assistance, European -- Mozambique , Economic development -- Mozambique , Mozambique -- Economic conditions , Autonomy , Budget -- Mozambique
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3378 , http://hdl.handle.net/10962/d1013218
  • Description: Post-colonial states in Africa continue to pursue nation-building and socio-economic development. This process is taking place with the sustained support of global agencies in terms of development cooperation, assistance and aid. Insofar as an endogenous development path which speaks to national priorities can be formulated and implemented by post-colonial states, their relationship with these agencies raises serious questions about such a path if the relationship entails dependence and indeed subordination of post-colonial states. This raises important questions about state autonomy under post-colonial conditions and the possibility of autonomy being compromised. In this light, the thesis examines European Union budget support to Mozambique and, in particular, the relationship between EU budget support and Mozambique state autonomy in pursuing national development. This is particularly pertinent given the massive dependence of the Mozambican state on foreign funding (notably EU funding) with specific regard to the national budget. Despite the broad claims existing in the prevailing literature that nation-state autonomy is seriously undermined in and through the international development system, the thesis argues against reductionist arguments that simply posit post-colonial states as mere instruments of global forces. This system, including European Union budget support, does indeed set the conditions of existence for post-colonial states such as Mozambique. But autonomy is necessarily relative and is subject to different forms and degrees. Ultimately, it is through empirical investigation that the specific form and degree of autonomy can be pinpointed and understood. The thesis contributes to this endeavour and suggests that the relationship between European budget support and Mozambican state autonomy is more complex and tension-riddled than the prevailing literature would seem to suggest.
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  • Date Issued: 2014

Understanding educators' and learners' perceptions and experiences of their participation in Science Fairs/Expos : a South African case study.

  • Authors: Kahenge, Wendelina Nambahu
  • Date: 2014
  • Subjects: Science fairs -- South Africa -- Grahamstown , Science -- Study and teaching -- South Africa -- Grahamstown , Vocational guidance -- South Africa -- Grahamstown , School children -- South Africa -- Attitudes , Teachers -- South Africa -- Attitudes , Teacher effectiveness -- South Africa -- Grahamstown
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1981 , http://hdl.handle.net/10962/d1013130
  • Description: The rationale behind Science Expos is to develop and empower learners to be able to identify problems and find solutions (Eskom Expo Project Guide Book, 2013). It is believed that involvement in Science Expos arouses learners' interest to pursue science related careers. But despite these ideals, there is still poor participation in Science Expos by educators and learners. I conducted this case study in five schools in Grahamstown, Eastern Cape, South Africa. The purpose of this study was to understand educators' and learners' perceptions and experiences of their participation in Science Expos. The case study was designed within an interpretive paradigm. The data were generated, triangulated and validated by a variety of methods, namely, document analysis, interviews (semi-structured and focus group) and observations. The main findings of the study were that learners who participate in Science Expos attend workshops organised by Scifest and SAEON office with the help of some of the educators and lecturers from Rhodes University. Learners' participation was influenced and assisted by the educators and peers with whom they were able to communicate and share their projects with. It emerged from the study that, as a result of participating in Science Expos, educators (teachers) and learners were exposed to a wide variety of scientific investigations and skills that are necessary for their classroom based-scientific investigations. It also emerged from this study that educators and learners face the challenge of a lack of motivation; insufficient support from schools and parents; time constraints to support learners in their participation and a lack of knowledge among some educators on their learners' projects. Some learners are even discouraged from participating in Science Expos by their peers on the grounds that they have no chance of winning. Teachers therefore require continuous mentorship and capacity building in order to encourage their learners to partake.
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  • Date Issued: 2014

Understanding food security in a perfect storm: an ecosystem services approach

  • Authors: Poppy, G M , Chiotha, S , Eigenbrod, Felix , Harvey, Celia A , Honza´k, M , Hudson, Malcolm D , Jarvis, A , Madise, Nyovani J , Schreckenberg, Kate , Shackleton, Charlie M , Villa, Ferdinando , Dawson, Terence P
  • Date: 2014
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/398423 , vital:69410 , xlink:href="https://doi.org/10.1098/rstb.2012.0288"
  • Description: Achieving food security in a ‘perfect storm’ scenario is a grand challenge for society. Climate change and an expanding global population act in concert to make global food security even more complex and demanding. As achieving food security and the millennium development goal (MDG) to eradicate hunger influences the attainment of other MDGs, it is imperative that we offer solutions which are complementary and do not oppose one another. Sustainable intensification of agriculture has been proposed as a way to address hunger while also minimizing further environmental impact. However, the desire to raise productivity and yields has historically led to a degraded environment, reduced biodiversity and a reduction in ecosystem services (ES), with the greatest impacts affecting the poor. This paper proposes that the ES framework coupled with a policy response framework, for example Driver-Pressure-State-Impact-Response (DPSIR), can allow food security to be delivered alongside healthy ecosystems, which provide many other valuable services to humankind. Too often, agro-ecosystems have been considered as separate from other natural ecosystems and insufficient attention has been paid to the way in which services can flow to and from the agro-ecosystem to surrounding ecosystems. Highlighting recent research in a large multi-disciplinary project (ASSETS), we illustrate the ES approach to food security using a case study from the Zomba district of Malawi.
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  • Date Issued: 2014

Understanding how trainee teachers engage with prior everyday knowledge and experience associated with biological concepts during integrated natural science education 5-7 : a case study

  • Authors: Enghono, Albertina Magano
  • Date: 2014
  • Subjects: Biology teachers -- Training of -- Namibia -- Case studies Teacher educators -- Training of -- Case studies Teachers -- Training of -- Namibia -- Case studies Education -- Namibia -- Case studies Prior learning -- Namibia
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1970 , http://hdl.handle.net/10962/d1011972
  • Description: Since the Namibian independence in 1990, the education system has undergone some major revamping which involved the adoption of social constructivist perspectives in the teaching and learning of sciences. This learning theory acknowledges learners’ background prior knowledge as valuable tools in the effective construction of science concepts during lessons. A corollary is that the socio-cultural circumstances of learners might negatively influence the way learners construct new knowledge in the science classroom if they are not taken into consideration. This study was thus prompted by the need to understand how trainee science teachers engage with prior everyday knowledge and experiences, so as to enhance the conceptual development of biological concepts. The study was qualitative and it was underpinned by an interpretive paradigm with some elements of action research. Science trainee teachers at Katima Mulilo, Unam Campus were used as research participants. The techniques used to gather data included document analysis, brainstorming, observation, audio-visual, microteaching and semi-structured interviews. The results of this study showed that the changes that occurred during microteaching practices of the four trainee teachers involved in the study reflected their professional development in this approach. However, it emerged that prior everyday knowledge can be both a barrier and enabler to the construction of meaningful teaching and learning; hence its oversight may lead to instructional failures. The findings also indicated that selected platforms are essential to enable trainee teachers to incorporate prior everyday knowledge and experiences into the teaching of Western science. However, larger scale study should be conducted in order to deepen the understanding of the topic.
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  • Date Issued: 2014

Understanding the livelihoods of child-grant mothers in Sinathingi in KwaZulu-Natal, South Africa

  • Authors: Motsetse, Matsepo Nomathemba
  • Date: 2014
  • Subjects: Welfare recipients -- South Africa -- KwaZulu-Natal , Social security -- South Africa , Family policy -- South Africa , Women -- South Africa -- KwaZulu-Natal -- Social conditions , Women -- South Africa -- KwaZulu-Natal -- Economic conditions , Poverty -- South Africa , Income -- South Africa -- KwaZulu-Natal
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3380 , http://hdl.handle.net/10962/d1013284
  • Description: The main focus of this thesis is the child support grant, as part of a broader social security system, in post-apartheid South Africa. Since the end of apartheid of 1994, the new South African government has sought to redress the racial imbalances and inequalities of the past by engaging in measures of redistribution. Central to this pursuit of redistribution has been a restructured system of social grants, of which the child support grant is the most significant. However, the post-apartheid government has adopted a largely neo-liberal macro-economic strategy such that social inequality and endemic poverty remain pervasive particularly amongst the African population, which includes the recipients of the child support grants. In adopting a sustainable livelihoods framework as the main theoretical perspective, the thesis seeks to understand the livelihoods of child support grant mothers in the face of conditions of extreme poverty. It does this through a localised study of twenty child grant mothers in Sinathingi Township in KwaZulu-Natal Province. In examining the livelihoods of these child-grant mothers, the thesis brings to the fore that mothers and their children do not exist as autonomous living units but are embedded in a broader set of social relations, including intra-household relations and relations with the fathers of the grant-children. It also demonstrates that child-grant mothers are not simply victims of structures of poverty in contemporary South Africa, but actively construct their livelihoods through a range of activities and strategies which show perseverance and ingenuity.
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  • Date Issued: 2014

Understanding the replication biology of Providence virus: elucidating the function of non-structural proteins

  • Authors: Nakayinga, Ritah
  • Date: 2014
  • Subjects: Insects Viruses , Viruses Reproduction , Tombusviridae , RNA viruses , RNA polymerases
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/193930 , vital:45408
  • Description: Tetraviruses are non-enveloped, small insect RNA viruses with a single stranded positive RNA genome that is either monopartite or bipartite. Providence virus (PrV) is the only member of the three tetravirus families with a viral replicase similar to the replicases of tombusviruses and umbraviruses. The principle aim of this thesis was to study PrV replication, focusing on subcellular localization and potential interactions between PrV replication proteins. The first objective of this study was to generate an anti-p104 antibody that does not cross-react with p40. Expression of the C-terminal portion of p104 in E. coli resulted in no detectable protein. Further expression in an insect cell based expression system resulted in the production of an insoluble protein. Attempts to improve protein solubility with a range of solubilization treatments were unsuccessful. Bioinformatic analysis was used to detect an antigenic region at the C-terminus of p104 and the peptide was used to raise anti-p104 antibodies. These antibodies did not detect native protein by western blot detection however they were used for immunoprecipitation. The establishment of the subcellular localization of PrV required two approaches; immunofluorescence in persistently infected Helicoverpa zea MG8 cells using antip40 and anti-dsRNA antibodies and the expression of EGFP-replicase fusion protein in Spodoptera frugiperda Sf9 cells. Replication of PrV was found to take place in cytosolic punctate structures. Co-immunoprecipitation experiments revealed that p40 self-interacts and interacts with p104. Bioinformatic analysis of PrV p104 suggests that the RdRp is similar to viral RdRps of the carmo-like supergroup II. Potential RNA binding regions are present within p104. A potential p40 interaction domain that shares hydrophilic and surface exposed properties with the TBSV p33 interaction domain is present. A putative arginine-rich region and disordered C-terminal region is present in p130. In conclusion, PrV p104 is the viral replicase. The resemblance of the expression strategy and putative functional domains with tombusviruses and umbraviruses suggest that PrV replication is related to the replication system of the tombusviruses and umbraviruses. This has led to propose that tetravirus replication strategies are diverse and raises questions on the origin and evolution of PrV. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
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  • Date Issued: 2014
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