The effect of extracellular Hsp90β and TGF-β1 on colon cancer biology
- Authors: Perks, Tamarin
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/55896 , vital:26753
- Description: The TGF-β signaling pathway is known to be one of the most commonly mutated pathways in human cancers, while Hsp90 is a bone fide drug target that is involved in regulating the conformation and activity of many oncoproteins. The role of intracellular Hsp90 in cancer has thus far been established and there is a growing link between extracellular Hsp90 and cancer metastasis, as well as the role of TGF-β in metastasis. This study aimed to analyse the interaction between Hsp90 (both intracellular and extracellular) and the TGF-β machinery in cancer cells, as well as to determine the effect of these proteins on cellular responses on the biology of cancer cells. This was achieved by studying the expression of Hsp90; TGF-βRII and TGF-β1 in cancer cell lines of various origins using flow cytometry, ELISA, and western blot analysis. The genetically paired SW480 and SW620 colon cancer cell lines, derived from a primary tumour and lymph node metastasis, respectively, were selected for further study due to differences in expression levels and activation of the TGF-β1 pathway. SW480 cells expressed double the level of TGF-βRII compared to SW620 cells, while SW620 expressed two times more extracellular TGF-β1 than SW480 cells. A direct interaction between TGF-β1 and Hsp90β was determined in vitro, and confirmed in vivo in SW620 cells. Growth, adhesion and migration were analysed in SW480 and SW620 cells. SW480 cells adhered significantly faster than SW620 cells, while SW620 cells had a greater rate of migration. Inhibiting the TGF-β pathway, specifically TGF-βRI, using SB 431542, as well as inhibiting Hsp90 with novobiocin, caused an increase in migration in SW480 cells. Only the addition of TGF-β1 in combination with Hsp90 as well as SB 431542 caused an increase in migration in SW620 cells. The canonical TGF-β1/TGF-βRI/TGF-βRII pathway may be constitutively active in SW620 cells and the inhibition of TGF-βRI may suggest an alternate pathway or receptor in both SW480 and SW620 cells.
- Full Text:
- Date Issued: 2015
- Authors: Perks, Tamarin
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/55896 , vital:26753
- Description: The TGF-β signaling pathway is known to be one of the most commonly mutated pathways in human cancers, while Hsp90 is a bone fide drug target that is involved in regulating the conformation and activity of many oncoproteins. The role of intracellular Hsp90 in cancer has thus far been established and there is a growing link between extracellular Hsp90 and cancer metastasis, as well as the role of TGF-β in metastasis. This study aimed to analyse the interaction between Hsp90 (both intracellular and extracellular) and the TGF-β machinery in cancer cells, as well as to determine the effect of these proteins on cellular responses on the biology of cancer cells. This was achieved by studying the expression of Hsp90; TGF-βRII and TGF-β1 in cancer cell lines of various origins using flow cytometry, ELISA, and western blot analysis. The genetically paired SW480 and SW620 colon cancer cell lines, derived from a primary tumour and lymph node metastasis, respectively, were selected for further study due to differences in expression levels and activation of the TGF-β1 pathway. SW480 cells expressed double the level of TGF-βRII compared to SW620 cells, while SW620 expressed two times more extracellular TGF-β1 than SW480 cells. A direct interaction between TGF-β1 and Hsp90β was determined in vitro, and confirmed in vivo in SW620 cells. Growth, adhesion and migration were analysed in SW480 and SW620 cells. SW480 cells adhered significantly faster than SW620 cells, while SW620 cells had a greater rate of migration. Inhibiting the TGF-β pathway, specifically TGF-βRI, using SB 431542, as well as inhibiting Hsp90 with novobiocin, caused an increase in migration in SW480 cells. Only the addition of TGF-β1 in combination with Hsp90 as well as SB 431542 caused an increase in migration in SW620 cells. The canonical TGF-β1/TGF-βRI/TGF-βRII pathway may be constitutively active in SW620 cells and the inhibition of TGF-βRI may suggest an alternate pathway or receptor in both SW480 and SW620 cells.
- Full Text:
- Date Issued: 2015
Investigating the effect of various film-forming polymers on the evaporation rate of a volatile component in a cosmetic formulation
- Authors: Barnard, Carla
- Date: 2010
- Subjects: Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10377 , http://hdl.handle.net/10948/1498 , Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Description: The topical application of many substances, including drugs, enzymes, moisturizers and fragrances, contributes largely to the cosmetic and pharmaceutical industries. These components are often volatile in nature and dissipate in a matter of hours. When considering the different types of slow release systems, an overwhelming variety of these systems is available. Each one of the systems is unique in a way, and is designed to perform a particular function, whether it facilitates the controlled release of an active into the body via the skin surface (transdermal delivery) or whether it reduces the rate of loss of an active from the skin surface to the surrounding environment. For the purpose of this study, a previously existing fixative formulation which is believed to reduce the rate of loss of an active component to the environment, through film formation on the skin surface, was investigated. Alternative ingredients or components were incorporated together with the original fixative formulation ingredients into an experimental design which investigates the effect of each group of the components present. 18 formulations with various concentrations of the components within the groups and specified upper and lower limits for each component were formulated. The fixative properties of the formulations were analysed through the incorporation of a fixed amount of a simple fragrance molecule, 4- methoxybenzaldehyde, into each formulation and evaporation studies were conducted in an environmental room at 28±1° C over a period of 5 hours followed by gas chromatography analysis and finally data analyses using statistical methods. The most efficient fixative formulation was established using regression analysis. The fragrance compound in this formulation was found to evaporate at a rate of 0.47 g/L per hour. The least efficient fixative formulation lead to the loss of 0.78 g/L of the fragrance component per hour. From the calculated fragrance concentrations, the rate constant for each individual fixative formulation could be calculated and response surface 8 modelling by backward regression was used in order to determine how each component contributes to the rate of loss of the fragrance compound. Since the sum of the original ingredient and its alternative was constant, each of the original ingredients was coupled directly to its alternative and no conclusion could be made about the contribution of individual components. By increasing the concentration of Hydroxypropylcellulose (HPC) 100K and its alternative HPC 140K, while keeping the effects of the other components constant, a decrease in the rate of fragrance loss was observed. The same conclusion could be made when increasing the concentrations of PEG-12 Dimethicone and its alternative cetyl dimethicone (decreases the evaporation rate). An interaction took place between HPC 100K and PEG-12 dimethicone and their alternatives. The negative effect was, however, not as strong as the combined positive effect on the rate of fragrance loss of the individual components HPC and PEG-12 dimethicone. Evidence suggested that the removal of the components polyvinylpyrrolidone and its alternative, polyurethane-32 (Baycusan® C1003), would improve the effectiveness of the fixative formulation in terms of its slow release properties. A confirmation experiment established that the exclusion of these components from the fixative formulation does improve the “slow release” properties thereof. A larger, more intricate design is required to investigate the effect of each one of the individual components and where the sum of the components (original and its alternative) is not constant.
- Full Text:
- Date Issued: 2010
- Authors: Barnard, Carla
- Date: 2010
- Subjects: Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10377 , http://hdl.handle.net/10948/1498 , Cosmetic delivery systems , Controlled release preparations , Cosmetics , Polymers , Drugs -- Controlled release
- Description: The topical application of many substances, including drugs, enzymes, moisturizers and fragrances, contributes largely to the cosmetic and pharmaceutical industries. These components are often volatile in nature and dissipate in a matter of hours. When considering the different types of slow release systems, an overwhelming variety of these systems is available. Each one of the systems is unique in a way, and is designed to perform a particular function, whether it facilitates the controlled release of an active into the body via the skin surface (transdermal delivery) or whether it reduces the rate of loss of an active from the skin surface to the surrounding environment. For the purpose of this study, a previously existing fixative formulation which is believed to reduce the rate of loss of an active component to the environment, through film formation on the skin surface, was investigated. Alternative ingredients or components were incorporated together with the original fixative formulation ingredients into an experimental design which investigates the effect of each group of the components present. 18 formulations with various concentrations of the components within the groups and specified upper and lower limits for each component were formulated. The fixative properties of the formulations were analysed through the incorporation of a fixed amount of a simple fragrance molecule, 4- methoxybenzaldehyde, into each formulation and evaporation studies were conducted in an environmental room at 28±1° C over a period of 5 hours followed by gas chromatography analysis and finally data analyses using statistical methods. The most efficient fixative formulation was established using regression analysis. The fragrance compound in this formulation was found to evaporate at a rate of 0.47 g/L per hour. The least efficient fixative formulation lead to the loss of 0.78 g/L of the fragrance component per hour. From the calculated fragrance concentrations, the rate constant for each individual fixative formulation could be calculated and response surface 8 modelling by backward regression was used in order to determine how each component contributes to the rate of loss of the fragrance compound. Since the sum of the original ingredient and its alternative was constant, each of the original ingredients was coupled directly to its alternative and no conclusion could be made about the contribution of individual components. By increasing the concentration of Hydroxypropylcellulose (HPC) 100K and its alternative HPC 140K, while keeping the effects of the other components constant, a decrease in the rate of fragrance loss was observed. The same conclusion could be made when increasing the concentrations of PEG-12 Dimethicone and its alternative cetyl dimethicone (decreases the evaporation rate). An interaction took place between HPC 100K and PEG-12 dimethicone and their alternatives. The negative effect was, however, not as strong as the combined positive effect on the rate of fragrance loss of the individual components HPC and PEG-12 dimethicone. Evidence suggested that the removal of the components polyvinylpyrrolidone and its alternative, polyurethane-32 (Baycusan® C1003), would improve the effectiveness of the fixative formulation in terms of its slow release properties. A confirmation experiment established that the exclusion of these components from the fixative formulation does improve the “slow release” properties thereof. A larger, more intricate design is required to investigate the effect of each one of the individual components and where the sum of the components (original and its alternative) is not constant.
- Full Text:
- Date Issued: 2010
The relationship between selected body composition components and self-efficacy among 12-14 year old rural adolescents in the Eastern Cape Province of South Africa
- Authors: Nkopo, Mandisi, S
- Date: 2017
- Subjects: Child development -- South Africa -- Eastern Cape Children -- Growth Body composition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4536 , vital:28403
- Description: Body composition changes drastically in both males and females during the adolescent years. The changes may have a negative effect on their physical health as well as psychological well-being, with respect to attributes such as self-efficacy. Being either overweight or obese during adolescence has social, economic and psychological consequences, which include low self-efficacy. However, very few international studies and not a single South African study could be found which measured the relationship of anthropometric body composition components, general self-efficacy levels and actual measured body size among adolescents, particularly among rural adolescents. Consequently, the aim of this study was to investigate the relationship between anthropometric body composition components and self efficacy, by conducting a comparison of self-efficacy levels among normal, overweight and obese 12 to 14-year-old rural adolescents in the Eastern Cape Province of South Africa. The sample consisted of boys (n=49) and girls (n=43) between the ages of 12 and 14 years. The body composition components were body weight, stature, body mass index, sum of 3 skinfolds, percentage body fat and hip-to-waist ratio. The sample was also classified into normal, overweight and obese groups, according to body mass index. A self-administered Self-Efficacy Questionnaire for Children (SEQ-C) which was developed by Muris (2001) was used to measure general self-efficacy. Data were analyzed by means of descriptive statistics, the Pearson correlation matrix and Cohen's effect size for significance (Cohen, 1992) and a Mann-Whitney U Test was used to determine statistical differences. Significance was set at p<0.05. Only 17 percent of the participants in the research sample were found to be overweight or obese. Only emotional self-efficacy showed significant (p=0.02) differences between the participants who were classified as having normal weights and the group which comprised the overweight and the obese groups. Overweight and obese boys and girls still had very high levels of self-efficacy, although their body mass index scores were high. Boys scored higher in social self-efficacy and girls in academic self-efficacy. Only girls presented significantly high correlations between body mass index and emotional self-efficacy (r=0.33, p=0.02), total self-efficacy and hip-to-waist ratio (r=0.44, p=0.00), social self-efficacy and hip-towaist ratio (r=0.39, p=0.01) and emotional self-efficacy and hip-to-waist ratio (r=0.33, p=0.02), while boys presented them only with respect to body weight (r=0.31, p=0.02) and stature (r=0.39, p=0.00). The results suggest that a positive relationship exists between body composition, in terms of hip-to-waist ratio, weight and stature, and self-efficacy among South African rural adolescents. However, girls presented significantly strong and positive correlations between hip-to-waist ratio and self-efficacy, whereas boys presented significant, strong and positive correlations between body weight, stature and self-efficacy. Only emotional self-efficacy showed significant differences between normal weight and overweight or obese South African rural adolescents. It seems likely that cultural beliefs may exert an influence on the psychosocial perceptions of adolescents in relation to body size, consequently affecting self efficacy levels.
- Full Text:
- Date Issued: 2017
- Authors: Nkopo, Mandisi, S
- Date: 2017
- Subjects: Child development -- South Africa -- Eastern Cape Children -- Growth Body composition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4536 , vital:28403
- Description: Body composition changes drastically in both males and females during the adolescent years. The changes may have a negative effect on their physical health as well as psychological well-being, with respect to attributes such as self-efficacy. Being either overweight or obese during adolescence has social, economic and psychological consequences, which include low self-efficacy. However, very few international studies and not a single South African study could be found which measured the relationship of anthropometric body composition components, general self-efficacy levels and actual measured body size among adolescents, particularly among rural adolescents. Consequently, the aim of this study was to investigate the relationship between anthropometric body composition components and self efficacy, by conducting a comparison of self-efficacy levels among normal, overweight and obese 12 to 14-year-old rural adolescents in the Eastern Cape Province of South Africa. The sample consisted of boys (n=49) and girls (n=43) between the ages of 12 and 14 years. The body composition components were body weight, stature, body mass index, sum of 3 skinfolds, percentage body fat and hip-to-waist ratio. The sample was also classified into normal, overweight and obese groups, according to body mass index. A self-administered Self-Efficacy Questionnaire for Children (SEQ-C) which was developed by Muris (2001) was used to measure general self-efficacy. Data were analyzed by means of descriptive statistics, the Pearson correlation matrix and Cohen's effect size for significance (Cohen, 1992) and a Mann-Whitney U Test was used to determine statistical differences. Significance was set at p<0.05. Only 17 percent of the participants in the research sample were found to be overweight or obese. Only emotional self-efficacy showed significant (p=0.02) differences between the participants who were classified as having normal weights and the group which comprised the overweight and the obese groups. Overweight and obese boys and girls still had very high levels of self-efficacy, although their body mass index scores were high. Boys scored higher in social self-efficacy and girls in academic self-efficacy. Only girls presented significantly high correlations between body mass index and emotional self-efficacy (r=0.33, p=0.02), total self-efficacy and hip-to-waist ratio (r=0.44, p=0.00), social self-efficacy and hip-towaist ratio (r=0.39, p=0.01) and emotional self-efficacy and hip-to-waist ratio (r=0.33, p=0.02), while boys presented them only with respect to body weight (r=0.31, p=0.02) and stature (r=0.39, p=0.00). The results suggest that a positive relationship exists between body composition, in terms of hip-to-waist ratio, weight and stature, and self-efficacy among South African rural adolescents. However, girls presented significantly strong and positive correlations between hip-to-waist ratio and self-efficacy, whereas boys presented significant, strong and positive correlations between body weight, stature and self-efficacy. Only emotional self-efficacy showed significant differences between normal weight and overweight or obese South African rural adolescents. It seems likely that cultural beliefs may exert an influence on the psychosocial perceptions of adolescents in relation to body size, consequently affecting self efficacy levels.
- Full Text:
- Date Issued: 2017
Microalgal biomass and distribution in the Mngazi and Mngazana Estuaries
- Ngesi, Hlekani Ntombizakithi
- Authors: Ngesi, Hlekani Ntombizakithi
- Date: 2010
- Subjects: Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10610 , http://hdl.handle.net/10948/1591 , Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Description: The present study was undertaken in the temporarily open/closed Mngazi and permanently open Mngazana estuaries, located on the subtropical east coast of South Africa. The results from this research will assist decision makers in the freshwater management of these systems. Intertidal and subtidal benthic chlorophyll a concentrations, water column chlorophyll a, nutrients and several physico-chemical parameters were measured between June 2002 and November 2003. The objective of this study was to determine if the presence of freshwater in the estuaries had an effect on the microalgae of both estuaries. Five sites were sampled in the Mngazi Estuary and 14 sites were sampled in the Mngazana Estuary. The average water column chlorophyll a was significantly higher (p<0.05) in the Mngazana Estuary (surface 7.8 ± 0.7 μg.l-1, bottom 6.4 ± 0.7 μg.l-1) compared to the Mngazi Estuary (surface 4.9 ± 1.2 μg.l-1, bottom 7.3 ± 1.5 μg.l-1). There was no evidence of an REI (river-estuary interface) zone in areas where the water column chlorophyll a concentrations were high even during open mouth conditions in the Mngazi Estuary. The REI is that area where salinity is less than 10 ppt and is characterized by high water column productivity. Even though both systems received some freshwater during the summer periods, this was not enough to stimulate phytoplankton growth and nutrient availability seems to be the major factor limiting phytoplankton in these systems. Flagellates and diatoms were the dominant phytoplankton groups in both estuaries during the entire sampling session. The relative abundance of the different phytoplankton groups did not show differences between sites. The relative abundance of flagellates was in most cases greater than 60% and diatoms made up the remainder. The average benthic chlorophyll a was higher in the Mngazana Estuary (intertidal 24 ± 6 μg.g-1 subtidal 15.2 ± 3 μg.g-1) compared to the Mngazi Estuary (intertidal 15.3 ± 4.3 μg.g-1 subtidal 5.4 ± 1.6 μg.g-1). Regions with high benthic chlorophyll a concentrations had high sediment organic content. Sediment organic content was higher in the Mngazana Estuary (1 percent - 8 percent) compared to the Mngazi Estuary (4 percent – 6.8 percent). The sites situated on the Main Channel had on average significantly higher (p<0.05) benthic chlorophyll a biomass compared to Creek 1 and Creek 2 in the Mngazana Estuary. Peaks in benthic chlorophyll a concentrations occurred in the intertidal sediments in Creek 1 (50.4 ± 13.4 μg.g-1) and Creek 2 (57.4 ± 1.4 μg.g-1) in the Mngazana Estuary, the peaks occurred in winter during a period of low freshwater inflow into the estuary. Microphytobenthic biomass measured in the Mngazi Estuary is among the lowest values reported in the literature for temporarily open/closed estuaries. Statistical 4 analysis showed no significant difference between benthic chlorophyll a during the different mouth conditions and sampling sessions in the Mngazi Estuary. Microalgal responses in the Mngazana Estuary were similar to those observed in other permanently open marine dominated estuaries. In the temporarily open/closed Mngazi Estuary microalgal characteristics were different to that of other temporarily open/closed estuaries probably because the estuary was only sampled in the open and semi-closed state.
- Full Text:
- Date Issued: 2010
- Authors: Ngesi, Hlekani Ntombizakithi
- Date: 2010
- Subjects: Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10610 , http://hdl.handle.net/10948/1591 , Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Description: The present study was undertaken in the temporarily open/closed Mngazi and permanently open Mngazana estuaries, located on the subtropical east coast of South Africa. The results from this research will assist decision makers in the freshwater management of these systems. Intertidal and subtidal benthic chlorophyll a concentrations, water column chlorophyll a, nutrients and several physico-chemical parameters were measured between June 2002 and November 2003. The objective of this study was to determine if the presence of freshwater in the estuaries had an effect on the microalgae of both estuaries. Five sites were sampled in the Mngazi Estuary and 14 sites were sampled in the Mngazana Estuary. The average water column chlorophyll a was significantly higher (p<0.05) in the Mngazana Estuary (surface 7.8 ± 0.7 μg.l-1, bottom 6.4 ± 0.7 μg.l-1) compared to the Mngazi Estuary (surface 4.9 ± 1.2 μg.l-1, bottom 7.3 ± 1.5 μg.l-1). There was no evidence of an REI (river-estuary interface) zone in areas where the water column chlorophyll a concentrations were high even during open mouth conditions in the Mngazi Estuary. The REI is that area where salinity is less than 10 ppt and is characterized by high water column productivity. Even though both systems received some freshwater during the summer periods, this was not enough to stimulate phytoplankton growth and nutrient availability seems to be the major factor limiting phytoplankton in these systems. Flagellates and diatoms were the dominant phytoplankton groups in both estuaries during the entire sampling session. The relative abundance of the different phytoplankton groups did not show differences between sites. The relative abundance of flagellates was in most cases greater than 60% and diatoms made up the remainder. The average benthic chlorophyll a was higher in the Mngazana Estuary (intertidal 24 ± 6 μg.g-1 subtidal 15.2 ± 3 μg.g-1) compared to the Mngazi Estuary (intertidal 15.3 ± 4.3 μg.g-1 subtidal 5.4 ± 1.6 μg.g-1). Regions with high benthic chlorophyll a concentrations had high sediment organic content. Sediment organic content was higher in the Mngazana Estuary (1 percent - 8 percent) compared to the Mngazi Estuary (4 percent – 6.8 percent). The sites situated on the Main Channel had on average significantly higher (p<0.05) benthic chlorophyll a biomass compared to Creek 1 and Creek 2 in the Mngazana Estuary. Peaks in benthic chlorophyll a concentrations occurred in the intertidal sediments in Creek 1 (50.4 ± 13.4 μg.g-1) and Creek 2 (57.4 ± 1.4 μg.g-1) in the Mngazana Estuary, the peaks occurred in winter during a period of low freshwater inflow into the estuary. Microphytobenthic biomass measured in the Mngazi Estuary is among the lowest values reported in the literature for temporarily open/closed estuaries. Statistical 4 analysis showed no significant difference between benthic chlorophyll a during the different mouth conditions and sampling sessions in the Mngazi Estuary. Microalgal responses in the Mngazana Estuary were similar to those observed in other permanently open marine dominated estuaries. In the temporarily open/closed Mngazi Estuary microalgal characteristics were different to that of other temporarily open/closed estuaries probably because the estuary was only sampled in the open and semi-closed state.
- Full Text:
- Date Issued: 2010
Microalgae biomass as fermentation feedstock
- Authors: Tijjani-Oshungboye, Kubura
- Date: 2012
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5956 , http://hdl.handle.net/10962/d1006168
- Description: The search for alternative energy is as a result of pollution generated by the utilization of fossil fuel. Bearing in mind the increase in demand which exceeds supply, alternative energy must reduce the carbon foot print in order to relieve use of fossil fuels. Biogas generation from wastes is an old technology that has been in existence for decades. This same concept was behind the development of the integrated algae ponding system (IAPS), where the use of microalgae biomass is adopted for waste water treatment and, anaerobic digestion which is a component of the IAPS, simultaneously generates biogas. The biogas from the IAPS was quantified in order to evaluate efficiency of the system and the anaerobic fermentation pit was also simulated in the laboratory to optimize biogas production using microalgae as co-fermentation feedstock. Microalgae biomass was evaluated as potential feedstock for ethanol fermentation and the use of biogas was investigated as an alternative transportation fuel. In an IAPS substantial biomass is produced on an annual basis. For effective treatment of waste water and efficient nutrient removal continuous harvest of the biomass is required. In the present study, water treatment efficiency of the EBRU IAPS was determined by carrying out a series of tests to investigate the decline in nutrient content from port of influent entry to effluent discharge. There was more than a 60% reduction in nutrient content with a concomitant increase in biomass and growth rate of 0.25 g/L . Biogas generated from the IAPS was quantified using a flow meter and the composition determined by gas chromatography. Methane which is the principal constituent of biogas was 75% (±SD, n=IO) and 2.34 m³.d⁻¹ was measured as biogas yield from the EBRU IAPS. The study also investigated the use of the excess microalgae biomass as a fermentation feedstock for ethanol production and as a co-substrate in order to increase biogas yield from the system. Positive results were achieved for ethanol production from microalgae although yield was generally low. About 385 mg.⁻¹ of ethanol was recovered when glucose was used as substrate, where as only 115 mg.⁻¹ of ethanol was recovered with microalgae as substrate. Suitability of microalgae as feedstock for ethanol generation and biogas generation was determined by characterisation which involved estimation of the carbohydrate, protein and lipid content, and analysis of the C, H, 0, Nand S content. Laboratory fed batch reactors simulated the anaerobic digestion process in order to study the effect of microalgae biomass as co-substrate for biogas generation. The fermenters were inoculated with an active consortium obtained from the Makana municipal waste water works and microbial studies were carried to confirm the presence of the anaerobic consortium. Different pre-treatments (concentrated, rupturing and freeze-drying) were used to disrupt the microalgae prior to introduction into fermenters in a ratio of 3: I. COD, TC, TOC, SO₄⁻² and TN analyses were carried out to monitor nutrient depletion in the system, and biogas generated by the system was quantified by volumetric analysis and the gas composition determined. Statistical analysis (ANOVA) was used to test for significant difference pre and post addition of microalgae. In the most effective fermenter, biogas production was at an average of 394 ml.d·' and CH₄ ratio in the biogas increased by over a 100%. Theoretical methane potential of the IAPS and the Makana municipal waste water works treating 5 ML.d⁻¹ of domestic waste was determined using the empirical formula of waste water and shown to yield 1,037,342.40 m³/yr. The projected biogas yield from this system was used to evaluate its potential use as transportation fuel. In total, 198,673 .55 m³ of biogas was estimated to be required to fuel the Rhodes University's fleet of vehicles, with a residual biogas stream of 838,668.85 m³. It was also demonstrated in the present study that renewable energy sourced from biomass has the potential of supplanting the use of fossil fuel resulting in less pollution leading to a cleaner and healthier environment.
- Full Text:
- Date Issued: 2012
- Authors: Tijjani-Oshungboye, Kubura
- Date: 2012
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5956 , http://hdl.handle.net/10962/d1006168
- Description: The search for alternative energy is as a result of pollution generated by the utilization of fossil fuel. Bearing in mind the increase in demand which exceeds supply, alternative energy must reduce the carbon foot print in order to relieve use of fossil fuels. Biogas generation from wastes is an old technology that has been in existence for decades. This same concept was behind the development of the integrated algae ponding system (IAPS), where the use of microalgae biomass is adopted for waste water treatment and, anaerobic digestion which is a component of the IAPS, simultaneously generates biogas. The biogas from the IAPS was quantified in order to evaluate efficiency of the system and the anaerobic fermentation pit was also simulated in the laboratory to optimize biogas production using microalgae as co-fermentation feedstock. Microalgae biomass was evaluated as potential feedstock for ethanol fermentation and the use of biogas was investigated as an alternative transportation fuel. In an IAPS substantial biomass is produced on an annual basis. For effective treatment of waste water and efficient nutrient removal continuous harvest of the biomass is required. In the present study, water treatment efficiency of the EBRU IAPS was determined by carrying out a series of tests to investigate the decline in nutrient content from port of influent entry to effluent discharge. There was more than a 60% reduction in nutrient content with a concomitant increase in biomass and growth rate of 0.25 g/L . Biogas generated from the IAPS was quantified using a flow meter and the composition determined by gas chromatography. Methane which is the principal constituent of biogas was 75% (±SD, n=IO) and 2.34 m³.d⁻¹ was measured as biogas yield from the EBRU IAPS. The study also investigated the use of the excess microalgae biomass as a fermentation feedstock for ethanol production and as a co-substrate in order to increase biogas yield from the system. Positive results were achieved for ethanol production from microalgae although yield was generally low. About 385 mg.⁻¹ of ethanol was recovered when glucose was used as substrate, where as only 115 mg.⁻¹ of ethanol was recovered with microalgae as substrate. Suitability of microalgae as feedstock for ethanol generation and biogas generation was determined by characterisation which involved estimation of the carbohydrate, protein and lipid content, and analysis of the C, H, 0, Nand S content. Laboratory fed batch reactors simulated the anaerobic digestion process in order to study the effect of microalgae biomass as co-substrate for biogas generation. The fermenters were inoculated with an active consortium obtained from the Makana municipal waste water works and microbial studies were carried to confirm the presence of the anaerobic consortium. Different pre-treatments (concentrated, rupturing and freeze-drying) were used to disrupt the microalgae prior to introduction into fermenters in a ratio of 3: I. COD, TC, TOC, SO₄⁻² and TN analyses were carried out to monitor nutrient depletion in the system, and biogas generated by the system was quantified by volumetric analysis and the gas composition determined. Statistical analysis (ANOVA) was used to test for significant difference pre and post addition of microalgae. In the most effective fermenter, biogas production was at an average of 394 ml.d·' and CH₄ ratio in the biogas increased by over a 100%. Theoretical methane potential of the IAPS and the Makana municipal waste water works treating 5 ML.d⁻¹ of domestic waste was determined using the empirical formula of waste water and shown to yield 1,037,342.40 m³/yr. The projected biogas yield from this system was used to evaluate its potential use as transportation fuel. In total, 198,673 .55 m³ of biogas was estimated to be required to fuel the Rhodes University's fleet of vehicles, with a residual biogas stream of 838,668.85 m³. It was also demonstrated in the present study that renewable energy sourced from biomass has the potential of supplanting the use of fossil fuel resulting in less pollution leading to a cleaner and healthier environment.
- Full Text:
- Date Issued: 2012
An investigation of the aquatic macroinvertebrate fauna of the southern Great Escarpment (South Africa): insights from ecological and genetic studies
- Authors: Taylor, Chantal Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4275 , http://hdl.handle.net/10962/d1020839
- Description: Biological diversity in freshwater biomes is vital to maintain healthy, functioning ecosystems with resilience to disturbance and the impacts of climate change. Freshwater ecosystems provide essential resources to life on Earth. However, as increasing pressure is being placed on the environment by human population growth, the quality of freshwater resources and the health of these ecosystems are at risk. Mountain streams provide an important source of water and are usually less affected by anthropogenic stressors, compared to lowland freshwaters. These montane streams are therefore of important conservation value and due to their untransformed nature serve as ideal ecosystems for biodiversity studies and as reference sites for studies on environmental change. This study explores aquatic macroinvertebrate biodiversity of the southern Great Escarpment in South Africa. Species assemblages and the environmental variables of each site were sampled from first order streams across five different mountain blocks along the Great Escarpment. Additionally, mitochondrial DNA of three mayfly species (Afroptilum sudafricanum, Demoreptus natalensis and Demoreptus capensis), commonly occurring in the study area, was analysed to compare the genetic diversity between habitat specialist and habitat generalist species. A total of 2 595 macroinvertebrate specimens from 47 families and 86 species were collected with several interesting and potentially new species being discovered. Partitioned diversity analyses indicate that macroinvertebrate diversity varies across mountain blocks. Multivariate analyses indicate that differences in assemblages could be attributed to differences in environmental variables between sites, particularly water velocity, total dissolved solids and salinity. As these environmental variables reflect of the topography of the sites, differences in species assemblages was attributed to difference in topography and therefore biotopes present. Habitat-restricted mayfly species (D. natalensis and D. capensis), occur in distinct populations confined to mountains blocks. Isolation-by-distance analyses further emphasis that these species are genetically restricted by their habitat preference for mountain streams. In contrast, A. sudafricanum, a habitat generalist, showed no indication of genetic structure due to location or distance. Possible cryptic taxa and new species were identified within A. sudafricanum and Dermoreptus respectively. This study provides an important contribution to the baseline data of freshwater macroinvertebrate diversity for the southern Great Escarpment region and provides insights into the considerable genetic diversity of selected aquatic taxa across this region.
- Full Text:
- Date Issued: 2016
- Authors: Taylor, Chantal Lee
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4275 , http://hdl.handle.net/10962/d1020839
- Description: Biological diversity in freshwater biomes is vital to maintain healthy, functioning ecosystems with resilience to disturbance and the impacts of climate change. Freshwater ecosystems provide essential resources to life on Earth. However, as increasing pressure is being placed on the environment by human population growth, the quality of freshwater resources and the health of these ecosystems are at risk. Mountain streams provide an important source of water and are usually less affected by anthropogenic stressors, compared to lowland freshwaters. These montane streams are therefore of important conservation value and due to their untransformed nature serve as ideal ecosystems for biodiversity studies and as reference sites for studies on environmental change. This study explores aquatic macroinvertebrate biodiversity of the southern Great Escarpment in South Africa. Species assemblages and the environmental variables of each site were sampled from first order streams across five different mountain blocks along the Great Escarpment. Additionally, mitochondrial DNA of three mayfly species (Afroptilum sudafricanum, Demoreptus natalensis and Demoreptus capensis), commonly occurring in the study area, was analysed to compare the genetic diversity between habitat specialist and habitat generalist species. A total of 2 595 macroinvertebrate specimens from 47 families and 86 species were collected with several interesting and potentially new species being discovered. Partitioned diversity analyses indicate that macroinvertebrate diversity varies across mountain blocks. Multivariate analyses indicate that differences in assemblages could be attributed to differences in environmental variables between sites, particularly water velocity, total dissolved solids and salinity. As these environmental variables reflect of the topography of the sites, differences in species assemblages was attributed to difference in topography and therefore biotopes present. Habitat-restricted mayfly species (D. natalensis and D. capensis), occur in distinct populations confined to mountains blocks. Isolation-by-distance analyses further emphasis that these species are genetically restricted by their habitat preference for mountain streams. In contrast, A. sudafricanum, a habitat generalist, showed no indication of genetic structure due to location or distance. Possible cryptic taxa and new species were identified within A. sudafricanum and Dermoreptus respectively. This study provides an important contribution to the baseline data of freshwater macroinvertebrate diversity for the southern Great Escarpment region and provides insights into the considerable genetic diversity of selected aquatic taxa across this region.
- Full Text:
- Date Issued: 2016
The diversity and distribution patterns of intertidal fish in the Agulhas bioregion
- Authors: Roux, Maryanne
- Date: 2013
- Subjects: Intertidal fishes , Marine fishes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10723 , http://hdl.handle.net/10948/d1019712
- Description: This study aimed to expand the existing knowledge on the diversity and distribution patterns of intertidal fishes in the Sardinia Bay MPA and adjacent open access areas. It focussed particularly on in intertidal fish communities along the Agulhas Bioregion coast which has been understudied, especially in recent years. Typical resident species belonging to the family Clinidae were the most abundant, conforming to previous studies. Species from the family Gobiidae were the second most abundant in this study but this family was not previously recorded as being abundant. Transient species were unimportant in the current study which is in contrast to previous studies in the region and suggests a change in species composition. Certain transient species utilised intertidal rockpools as part of their nursery areas in the Eastern Cape, as has previously been found around Algoa Bay. A decrease in species richness from east to west was recorded in this study which has been noted by previous authors and the diversity and distribution patterns of the intertidal fish in the current study conformed to patterns found previously. The position of the biogeographic boundary between the Agulhas and Natal Bioregions could not be confirmed but Wavecrest (along the Transkei coastline) appeared to be part of a transition zone rather than a fixed break. More sampling around this area is recommended to determine the location and understand the dynamic nature of this boundary. The fish species were found to be vertically distributed across the shore with most of the resident species being more abundant across the low shore while the transient species were more abundant in the middle to low shore pools. This vertical distribution has been found at many sites around the world. The volume of the pools proved to be the primary controlling factor while the effect of temperature on vertical distribution could not be demonstrated. The benefits of the Sardinia Bay Marine Protected Area on this unexploited community of fishes could not be demonstrated but the long term benefit of protection has yet to be shown. Results from this study suggest that despite the correspondence with general biogeographic trends, the intertidal fish community has changed in composition (at least in terms of transient species) during the last 30 years and the cause for these changes may in part be reduced recruitment from exploited linefish.
- Full Text:
- Date Issued: 2013
- Authors: Roux, Maryanne
- Date: 2013
- Subjects: Intertidal fishes , Marine fishes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10723 , http://hdl.handle.net/10948/d1019712
- Description: This study aimed to expand the existing knowledge on the diversity and distribution patterns of intertidal fishes in the Sardinia Bay MPA and adjacent open access areas. It focussed particularly on in intertidal fish communities along the Agulhas Bioregion coast which has been understudied, especially in recent years. Typical resident species belonging to the family Clinidae were the most abundant, conforming to previous studies. Species from the family Gobiidae were the second most abundant in this study but this family was not previously recorded as being abundant. Transient species were unimportant in the current study which is in contrast to previous studies in the region and suggests a change in species composition. Certain transient species utilised intertidal rockpools as part of their nursery areas in the Eastern Cape, as has previously been found around Algoa Bay. A decrease in species richness from east to west was recorded in this study which has been noted by previous authors and the diversity and distribution patterns of the intertidal fish in the current study conformed to patterns found previously. The position of the biogeographic boundary between the Agulhas and Natal Bioregions could not be confirmed but Wavecrest (along the Transkei coastline) appeared to be part of a transition zone rather than a fixed break. More sampling around this area is recommended to determine the location and understand the dynamic nature of this boundary. The fish species were found to be vertically distributed across the shore with most of the resident species being more abundant across the low shore while the transient species were more abundant in the middle to low shore pools. This vertical distribution has been found at many sites around the world. The volume of the pools proved to be the primary controlling factor while the effect of temperature on vertical distribution could not be demonstrated. The benefits of the Sardinia Bay Marine Protected Area on this unexploited community of fishes could not be demonstrated but the long term benefit of protection has yet to be shown. Results from this study suggest that despite the correspondence with general biogeographic trends, the intertidal fish community has changed in composition (at least in terms of transient species) during the last 30 years and the cause for these changes may in part be reduced recruitment from exploited linefish.
- Full Text:
- Date Issued: 2013
Maintenance of university facilities in developing countries
- Authors: Bowazi, Kenneth Mtunduwatha
- Date: 2011
- Subjects: College facilities -- Developing countries , Educational planning -- Developing countries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9723 , http://hdl.handle.net/10948/d1008472 , College facilities -- Developing countries , Educational planning -- Developing countries
- Description: Universities in developing countries are deteriorating physically due to lack of planned maintenance, lack of maintenance policies in the institutions, lack of up-to-date security system, and also lack of qualified personnel at decision-making level. Lack of planning leads to reactive maintenance. It also leads to unbudgeted expenditure and has an impact on the amount of money allocated to maintenance which results in unavailability of funds to carry out maintenance duties. Institutions which have no maintenance policy lack guidelines to follow when a maintenance problem arises. Most personnel in charge of maintenance are junior management or at supervisory level as a result they are not part of middle management that strategically directs the organisation. Most of the decisions made at supervisory scale are easily overruled at management level where the maintenance manager is not present during meetings to motivate maintenance cases. Lack of efficient security also allows vandalism to rise which contributes to the deterioration of facilities. Universities lack creativity and cost management skills to raise its own funds to supplement the maintenance budget, which is largely funded by the government. This study recommends employment of built environment professionals in decision-making positions. It also recommends that organizations should have a maintenance policy in place. Investment should be made in good security systems and management of the facilities should include income generating activities that could subsidise the maintenance budget.
- Full Text:
- Date Issued: 2011
- Authors: Bowazi, Kenneth Mtunduwatha
- Date: 2011
- Subjects: College facilities -- Developing countries , Educational planning -- Developing countries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9723 , http://hdl.handle.net/10948/d1008472 , College facilities -- Developing countries , Educational planning -- Developing countries
- Description: Universities in developing countries are deteriorating physically due to lack of planned maintenance, lack of maintenance policies in the institutions, lack of up-to-date security system, and also lack of qualified personnel at decision-making level. Lack of planning leads to reactive maintenance. It also leads to unbudgeted expenditure and has an impact on the amount of money allocated to maintenance which results in unavailability of funds to carry out maintenance duties. Institutions which have no maintenance policy lack guidelines to follow when a maintenance problem arises. Most personnel in charge of maintenance are junior management or at supervisory level as a result they are not part of middle management that strategically directs the organisation. Most of the decisions made at supervisory scale are easily overruled at management level where the maintenance manager is not present during meetings to motivate maintenance cases. Lack of efficient security also allows vandalism to rise which contributes to the deterioration of facilities. Universities lack creativity and cost management skills to raise its own funds to supplement the maintenance budget, which is largely funded by the government. This study recommends employment of built environment professionals in decision-making positions. It also recommends that organizations should have a maintenance policy in place. Investment should be made in good security systems and management of the facilities should include income generating activities that could subsidise the maintenance budget.
- Full Text:
- Date Issued: 2011
An assessment of density estimation methods for forest ungulates
- Authors: Ellis, Amanda Morgan
- Date: 2004
- Subjects: Wildlife management -- South Africa -- Eastern Cape Animal populations -- Estimates Wildlife conservation -- South Africa -- Eastern Cape Game farms -- South Africa -- Eastern Cape Ungulates -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5829 , http://hdl.handle.net/10962/d1007830
- Description: The development of conservation and management programs for an animal population relies on a knowledge of the number of individuals in an area. In order to achieve reliable estimates, precise and accurate techniques for estimating population densities are needed. This study compared the use of direct and indirect methods of estimating kudu (Trage/aphus strepsiceras), bush buck (Trage/aphus scriptus), common duiker (Sy/vicapra grimmia), and blue duiker (Philantamba manticala) densities on Shamwari Game Reserve in the Eastern Cape Province, South Africa. These species prefer habitats of dense forest and bush for concealment and are therefore not easily counted in open areas. Herein direct observation counts were compared to indirect sampling via pellet group counts (clearance plots, line transects, variable-width transects, and strip transects). Clearance plots were examined every 2 weeks, while all other methods were conducted seasonally, from August 2002 until August 2003. The strip transect method provided the lowest density estimates (animals per hal ranging from 0.001 for bushbuck to 0.025 for common duiker, while direct observations yielded the highest estimates, ranging from 0.804 for bush buck to 4.692 for kudu. Also, a validation of methods was performed against a known population of kudu during which the DISTANCE method yielded the most accurate results, with an estimated density of 0.261 that was within the actual density of 0.246 to 0.282. In addition, the DISTANCE method was compared to helicopter counts ofkudu and its estimates were found to be approximately 2.6 times greater than the helicopter count results. When the assessment of the methods was made, the cost, manpower and effort requirements, coefficient of variation, and performance against a known population for each method were taken into consideration. Overall, the DISTANCE method performed the best with low cost, minimal manpower and effort requirements, and low coefficient of variation. On Shamwari Game Reserve, the DISTANCE method estimated 0.300 kudu, 0.108 bushbuck, 0.387 common duiker, and 0.028 blue duiker per ha, which, when extrapolated to the total number of animals present within subtropical thicket habitat, estimated 1973 kudu, 710 bush buck, 2545 common duiker, and 184 blue duiker.
- Full Text:
- Date Issued: 2004
- Authors: Ellis, Amanda Morgan
- Date: 2004
- Subjects: Wildlife management -- South Africa -- Eastern Cape Animal populations -- Estimates Wildlife conservation -- South Africa -- Eastern Cape Game farms -- South Africa -- Eastern Cape Ungulates -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5829 , http://hdl.handle.net/10962/d1007830
- Description: The development of conservation and management programs for an animal population relies on a knowledge of the number of individuals in an area. In order to achieve reliable estimates, precise and accurate techniques for estimating population densities are needed. This study compared the use of direct and indirect methods of estimating kudu (Trage/aphus strepsiceras), bush buck (Trage/aphus scriptus), common duiker (Sy/vicapra grimmia), and blue duiker (Philantamba manticala) densities on Shamwari Game Reserve in the Eastern Cape Province, South Africa. These species prefer habitats of dense forest and bush for concealment and are therefore not easily counted in open areas. Herein direct observation counts were compared to indirect sampling via pellet group counts (clearance plots, line transects, variable-width transects, and strip transects). Clearance plots were examined every 2 weeks, while all other methods were conducted seasonally, from August 2002 until August 2003. The strip transect method provided the lowest density estimates (animals per hal ranging from 0.001 for bushbuck to 0.025 for common duiker, while direct observations yielded the highest estimates, ranging from 0.804 for bush buck to 4.692 for kudu. Also, a validation of methods was performed against a known population of kudu during which the DISTANCE method yielded the most accurate results, with an estimated density of 0.261 that was within the actual density of 0.246 to 0.282. In addition, the DISTANCE method was compared to helicopter counts ofkudu and its estimates were found to be approximately 2.6 times greater than the helicopter count results. When the assessment of the methods was made, the cost, manpower and effort requirements, coefficient of variation, and performance against a known population for each method were taken into consideration. Overall, the DISTANCE method performed the best with low cost, minimal manpower and effort requirements, and low coefficient of variation. On Shamwari Game Reserve, the DISTANCE method estimated 0.300 kudu, 0.108 bushbuck, 0.387 common duiker, and 0.028 blue duiker per ha, which, when extrapolated to the total number of animals present within subtropical thicket habitat, estimated 1973 kudu, 710 bush buck, 2545 common duiker, and 184 blue duiker.
- Full Text:
- Date Issued: 2004
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