Characterisation of antibacterial compounds produced by Pseudomonas spp. isolated from Hogsback wetlands, Eastern Cape, South Africa
- Authors: Obi, Akudo Odochi
- Date: 2017
- Subjects: Bacteriology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15688 , vital:40507
- Description: With microbial pathogens developing resistance against currently existing antimicrobials, there is an earnest need to discover and develop new therapeutic compounds with unique and/or precise modes of action. Natural products have provided the inspiration for most of the active ingredients in medicines and thus are regarded as a potential screening resource lead for discovery of new drugs. Pseudomonads are ubiquitous, Gram-negative, motile bacteria that flourish and inhabit a diversity of environments. Literature has vastly revealed that some members of the genus Pseudomonas are capable of producing a plethora of biologically active metabolites and thus are regarded as “attractive” bacteria for testing as potential sources for new therapeutic compounds. In this regard, this study was undertaken with an aim to isolate and characterize antibacterial compounds produced by Pseudomonas species isolated from aquatic milieu of the Hogsback wetlands, Eastern Cape, South Africa. A total of 12 water samples were aseptically collected from Hogsback wetlands. To ascertain antimicrobial potential of the isolates, 9 test bacterial (sensitive) strains, namely Escherichia coli ATCC 3695, Vibrio fluvialis, Salmonella typhimurium, Salmonella enteritidis, Pseudomonas aeruginosa ATCC 27853, Escherichia coli (2), Listeria ivanovii, Listeria monocytogenes and Enterococcus faecalis ATCC 19433 were used for antimicrobial screening. A total of 500 presumptive Pseudomonas spp. were isolated and screened for the production of antibacterial compound through the Agar-well diffusion method. About 8percent of the presumptive Pseudomonas spp. produced compound with activity against the test bacteria and based on the levels of activity shown, three isolates coded as A53, Y55 and Y138 were selected and identified by 16S rDNA sequence analysis and The Basic Local Alignment Search Tool analysis revealed that the three isolates (A53, Y55 and Y138) belonged to the Pseudomonas genus. Using MEGA6 software, a molecular phylogenetic tree was constructed by Maximum Likelihood Method. The phylogenetic analysis by this method showed that all three isolate codes (A53, Y55 and Y138) formed the same clade with Pseudomonas viridiflava strain P3 (Accession number: AY972186) and Pseudomonas plecoglossicida strain P9 (Accession number: AY972231) at a high bootstrap value of 100percent. Isolate code A53 and Y55 also grouped together at a bootstrap value of 96percent. Factors affecting antibacterial compound production by the three isolates were elucidated. The effect of pH on the three isolates revealed that isolate code A53 and Y55 could produce antibacterial compounds over all pH ranges (pH 4-9), however, antibacterial production was produced optimally at acidic conditions (pH 4) and a less acidic-neutral condition (pH 6) respectively. Isolate Y138 showed optimal production at pH 5. The effect of temperature on all three isolates was studied at different temperatures ranging between 25°C-40°C. Study on effect of temperature variations on antibacterial production revealed that all three isolates are capable of growing and producing antibacterial compounds over all the different temperature ranges, however, maximum/optimum production was observed at temperature of 30°C. In order to establish the role of plasmids in antibacterial production, two curing agents; Sodium dodecyl sulfate (SDS) and Ethidium bromide under different sub-lethal concentrations (1 mg/ml -11mg/ml and 2.5 μg/ml- 125 μg/ml respectively) were used to cure the selected isolates. Plasmid DNA samples of A53, Y55 and Y138, were separated by electrophoresis on a 0.7percent (w/v) agarose. Agarose gel electrophoresis revealed that not all the concentrations used were effective in curing the plasmid. A Quick Load 1 kb Extend DNA ladder marker was used for determining the size of the plasmids. Isolate code A53 and Y138 had a plasmid size of 48.5 kb while isolate Y55 had a plasmid size of approximately 20 kb. Antibacterial activity by agar-well diffusion method after the curing process revealed that antibacterial production was not lost or prevented, but rather increased. Thus, it is suggested that the genes responsible for antibiotic production in this study were chromosomal-encoded and not plasmid-encoded. This study revealed that Hogsback wetlands may represent a previously unexplored environment/source of discovering novel and potent antibacterial compounds.
- Full Text:
- Date Issued: 2017
Characterisation, antimalarial and biological activities of secondary metabolites from leaves of anonidium mannii
- Authors: Makoni, Pfungwa Gervase
- Date: 2017
- Subjects: Anonidium mannii -- Therapeutic use , Botanical chemistry , Annonaceae -- Therapeutic use , Apocynaceae -- Therapeutic use , Malaria -- Chemotherapy , Tuberculosis -- Chemotherapy , Bacterial diseases -- Chemotherapy , Cancer -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4797 , vital:20725
- Description: Anonidium mannii is a plant of the Annonaceae genus which is used traditionally in Africa for the treatment of gonorrhoea, malaria, cancer, skin inflammation and dysentery. In this study we will evaluate antimalarial, antifungal, anti - tuberculosis, antibacterial activities and cytotoxicity of different fractions in order to provide a scientific rationale for the traditional use of Anonidium mannii as well as provide possible novel drugs in the treatment of multi drug resistant strains of parasites and bacteria. Extracts from dried leaves were obtained by using solvent extraction and different fractions obtained using column chromatography eluted with solvents of varying polarities to obtain a wide range of metabolites. The antimalarial activity of the various fractions and some pure compounds was evaluated using plasmodium lactate dehydrogenase (pLDH) assay. Cytotoxicity was evaluated using HeLa cells while anti – tuberculosis assay was evaluated using the green fluorescent protein. Antibacterial activity of the extracts was evaluated using micro-dilution assay against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria and Gram-negative (Escherichia coli and Salmonella typhi) bacteria. Antifungal activity was evaluated against Candida albicans. The antimalarial assays yielded some fractions with promising IC50 values. The selected fractions yielded activities ranging between 0.73 μg/mL and 20.23 μg/mL. The fraction with the best activity was obtained from a hexane/ethyl acetate fraction. AM1C, a cholestane, showed the best activity from the pure metabolites that were screened. AM3C, stigmasterol, a pure compound gave the best antifungal activity with an MIC of 0.063 μg/mL. AM9C another pure compound (sterol) showed the best activity against S. typhi with a value of 0.031 μg/mL. AM2C a pure compound showed an activity of 0.063 μg/mL against E. faecalis. The best cytotoxicity was demonstrated by the fraction C2AM3P with a cell viability of 7.1 ± 0.2 % while AM1C had a viability of 20.2 ± 1.2 %. Several pure metabolites were isolated and four of these were positively identified as steroids. Of these steroids the structure of three novel metabolites from A. mannii was deduced. The study showed promising antibacterial, antifungal, anti – tuberculosis, antimalarial and anticancer activity of A. mannii. These results validate the use of A. manni against cancer, skin inflammation which is caused by fungus, malaria and bacterial diseases.
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- Date Issued: 2017
Characterization of a glycated gelatin model to explore the therapeutic properties of macrofungi in diabetic wound healing: an in vitro study
- Authors: Pringle, Nadine Alex
- Date: 2017
- Subjects: Diabetes -- Animal models Chronic diseases -- Age factors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/11992 , vital:27017
- Description: Diabetic wounds frequently undergo impaired and prolonged wound healing due to a multitude of factors including hypoxia, impaired angiogenesis, hyperglycaemia, formation of ROS and AGEs, and infection - all of which may lead to cellular dysfunction. To date, however, treatment options for individuals suffering from impaired diabetic wound healing are limited, non-specific, and generally unsuccessful. The search for new and effective treatment strategies is severely hampered by the availability of adequately characterized screening models which comprehensively mimic the complexity of the diabetic wound healing process. In order to explore natural products as potential therapeutics to treat diabetic wounds and to encourage more research on this topic, this study sought out to develop and characterize a more convenient and cost effective in vitro screening assay which mimics the effects of protein glycation on the healing process of diabetic wounds. As proof of principal, this model was subsequently used to screen the potential of five wild mushroom species (P. tinctorius, R. capensis, B. badius, P. ostreatus and G. lucidum) as suitable diabetic wound healing therapies. The glycated gelatin model developed during this study was found to suitably mimic the diabetic state as it successfully simulated the major cellular dysfunctions in macrophages (NO production, phagocytosis, macrophage polarization, NF-ĸB translocation and COX-2 expression) and fibroblasts (proliferation and migration) documented during diabetic wound healing. Together these findings provide confidence that the model may serve as a valuable tool to study the poorly understood mechanisms which characterize cellular dysfunction in response to AGE accumulation and also to aid the identification of novel therapeutic agents to treat this pathology. Screening a number of mushroom extracts revealed that the ethanol extracts of R. capensis and P. ostreatus had the greatest potential for attenuating chronic inflammation due to their ability to promote macrophage phagocytosis, increased M2 activation (R. capensis) and decreased M1 activation (P. ostreatus) as well as reduced COX-2 expression while the water extract of G. lucidum proved to be the most promising candidate for stimulating fibroplasia as it was the most successful at promoting both fibroblast proliferation and migration. Different mushroom species were thus shown to promote different stages of the wound healing process providing sufficient evidence to support further studies related to the use of macrofungi as therapeutic agents in the search for more cost-effective and efficient treatment strategies for impaired diabetic wound healing.
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- Date Issued: 2017
Characterization of livestock manures biochar and their effect on soil chemical properties and crop growth under glasshouse conditions
- Authors: Dzvene, Admire Rukudzo
- Date: 2017
- Subjects: Biochar Soil fertility
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9863 , vital:35091
- Description: Biochar is being promoted as an amendment to improve soil properties, crop productivity, and carbon sequestration. In Africa, biochar adoption is hindered by production systems which include technology and feedstocks availability. However, little research has been published on the influence of biochar incorporation on soil chemical properties and early crop establishment. The aim of this study was to characterize biochar from cattle, goat, sheep and poultry kraal manures and their effect on soil properties and crop growth. This was guided by the following specific objectives, (i) to explore the mixed-farming system of Raymond Mhlaba Municipality on availability and utilization of livestock kraal manures (ii) to characterize biochar samples produced from cattle, goat, sheep and poultry kraal manures (iii) to determine the nutrient release patterns of biochars amended in a degraded soil (iv) to determine the effectiveness of converting manure to biochar and cattle manure on maize early development and, (v) to determine the effects of biochar type and application rate on early maize development. The farming system was surveyed to identify quantities of livestock manure, its availability and utilization for soil fertility amendment in cropping in the Raymond Mhlaba Municipality. The emerging results across all the villages revealed that, the mean livestock numbers were, 9.24±8.21 sheep, 9.37±8.15 goats, 7.95±7.66 cattle and 9.02±9.47 chickens. The findings revealed that 94 (82.4percent) of the respondents had access to cropland allocations in the form of outfields and homegardens. However, only 55 (48.2percent) of the respondents were currently cropping their fields. Maize was the most common crop grown followed by butternuts and potatoes. The application of manure by the respondents currently cropping their lands was only 40 (35.1percent) and the quantities used ranged from 210-1450 kg ha-1. The results further showed that the estimated total manure production was 2.9 t year-1, 0.82 t year-1, 0.04 t year-1, and 0.8 t year-1 from cattle, goats, chicken, and sheeps respectively. Drum retort method of slow pyrolysis at a temperature of 400°C was used to produce biochar from cattle, goat, sheep and poultry manure feedstocks. The biochar yields were 63percent, 72percent, 61percent and 83percent on a weight basis for the different feedstocks. The chemical properties of the biochar were significantly different from those of the manure from which they were made. Biochars that were high in Ca and K such as poultry manure biochar and sheep manure biochar indicated higher pH and electrical conductivity values. For instance, sheep manure biochar was (8.1 mS cm-1) and poultry manure biochar was (9.2 mS cm-1). The scanning electron microscopy (SEM) revealed that, the biochars had porous structures ranging from 1.23um to 5.23um in diameter which are important for water conductance and holding capacity. The target soil carbon level to determine the effects of biochar soil incorporation was 2percent and the soil had 0.7percent. Therefore, it was treated with four livestock manure biochars at application rates of 0; 53.2 t ha-1 (CMB); 48.1 t ha-1 (GMB); 50.7 t ha-1 (SMB); and 40.2 t ha-1 (PMB) based on their carbon content to supplement the soil carbon difference. The effect on soil pH was such that SMB increased to 6.44, PMB (6.45), CMB (6.54), and GMB (6.53) relative to the control which did not show any changes. An increase was also observed on Olsen P concentrations (mg P kg-1) which varied with biochar treatments: PMB (6.22), GMB (6.37), SMB (6.44) and CMB (6.44) and were significantly higher than the control. Ammonium-N(NH4+) concentrations (mg NH4+-N) were increased in biochar treatments but, no significant differences were obtained with sampling time. SMB released 7.95 mg kg-1, CMB 7.50 mg kg- 1, PMB 7.46 mg kg-1 and GMB 7.05 mg kg-1, compared to the control 3.23 mg kg-1. Maize growth in soil sampled from farmers fields in cultivation and abandoned treated with biochar without application of inorganic fertilizer did not differ with control (soil only) treatments. However, maize growth in soil treated with biochar and inorganic fertilizer was comparative to manure treatments. This resulted in a follow up study to elucidate the effects of biochar alone and was carried out with cattle, goat, sheep and poultry biochars at five application rates (0, 100, 200, 300, and 400 kg C ha-1) applied to a sandy loam and a clayey loam soil of the Oakleaf and Tukulu soil forms respectively. Post-harvest soil pH, electrical conductivity and Olsen P showed improvements in biochar treatments relative to the control. Improvements in the chemical parameters and plant growth increased simultaneously with biochar application rate. Maize growth was not affected by biochar application at different rates.
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- Date Issued: 2017
Characterization of maize biochars, their effects on soils, early maize growth and effectiveness of fertilizers
- Authors: Pinkson, Sibusisiwe
- Date: 2017
- Subjects: Soil fertility Crops and soils Biochar
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9974 , vital:35211
- Description: The use of maize biochar in smallholder cropping systems of the Eastern Cape (EC) Province could be a strategy that helps mitigate a common challenge such as poor soil fertility in maize productivity. The current study investigated the following: a) comparison of maize biochars derived from the drum and pit kiln pyrolytic systems as soil amendments; b) effects of maize biochars on soil acidity and extractable nutrients of three arable soil types of the EC Province; c) effects of maize biochars on early maize growth and nutrient uptake; d) effect of maize biochars on the effectiveness of organic and inorganic fertilizers for improved soil quality and maize growth. Maize biochars were produced from two pyrolytic systems namely the pit and drum kiln, each maize biochar type was analyzed with respect to its chemical and physical characteristics to investigate its potential as a soil amendment. Both pyrolytic systems were monitored to identify optimum pyrolytic temperatures reached by each process. Observed peak pyrolytic temperature were 300 °C and 500 °C for the pit and drum pyrolytic systems respectively. Both maize biochar types were alkaline in nature with pH values of 8.36 (H2O) and 7.45 (KCl) and 8.95 (H2O) and 7.82 (KCl) for pit and drum biochar respectively. Electrical conductivity (Ec) of drum biochar was 199 mS /m and that of pit biochar 186 mS /m. Generally, there were no differences in the chemical compositions of the two biochar types. However, in most analysis drum biochar gave higher values in nutrient composition compared to the pit biochar. Moreover, according to SEM analysis both biochar materials consisted of an increase in pore size distribution compared to the original feedstock material. In addition, an increase in nutrient composition in the two biochar types compared to the original feedstock was also observed. In an incubation experiment, potential effects of the two maize biochar types derived from the pit and drum kiln pyrolytic systems on soil acidity and nutrients were investigated on three arable soil types of the EC Province. Three soil types investigated were obtained from the University of Fort Hare (UFH), Phandulwazi (PND) and Msobomvu (MSV). The UFH soil was a sandy loam of the Oakleaf form or Eutric Cambisol, the PND soil was a sandy loam over sandy clay a Haplic Luvisol, while the MSV soil was a clay loam of Westleigh form a Ferric luvisol. Both maize biochar types significantly (p< 0.05) increased soil pH of the three soil types in the incubation study from an average of 4.68- 7.5. Soil pH improvement was in the following order pit biochar> drum biochar> control. Also, the two maize biochar types significantly (p< 0.05) increased the release of cations namely Ca, Mg and Na however, some decrease in nutrient concentrations were observed due to increase in pH levels at the later stage of the study. Biochar incorporation increased extractable P release from 30- 40 mg P/kg to an average range of between 120- 160 mg P/kg across all soil types. A glasshouse study was also conducted investigating the effect of different biochar rates of the two maize biochar types used in the previous studies on early maize growth and nutrient uptake, same soil types were used as those in the incubation study. Biochar was applied at application rates of 0, 100, 200 and 300 kg C/ha of biochar. The glasshouse experiment consisted of two cycles, each with a six week period of monitoring maize seedling growth development. Generally, a significant increase in maize growth parameters such as plant height, stem girth, number of leaves and leaf area increased after biochar additions compared to the control. Both biochars significantly improved maize seedling growth at an application rate of 200 kg C/haHowever, the two biochar types displayed varying impacts on maize growth due to influence of soil type and biochar application rates. Nutrient- uptake of Ca, P, Na and Mg showed to improve at an application rate of 200 kg C/ha for both biochar types showing a 50 percent increase compared to the control. Nutrient- uptake patterns for P, Ca, Mg and Na differed across all soil types, mainly due to changes in pH and Na levels which were influenced by increased biochar concentrations resulting in nutrient deficiency. Another glasshouse experiment aimed at investigating the effects on the two maize biochar types on influencing the effectiveness of both organic and inorganic fertilizers for improved early maize growth and soil productivity. Biochar was applied at an application rate of 400 kg C/ha of biochar, fertilizer was applied at application rates of 0, 10, 20, 30 and 40 kg N/ha and manure at 0, 10, 20, 30 and 40 t/ha respectively. The glasshouse experiment consisted of two cycles, each with a six week period of monitoring maize seedling growth development. In the 1st cycle, manure rate of 40 t/ha resulted in the highest plant height of maize seedlings grown in the glasshouse, biochar type also showed to influence plant height. After the 1st harvest Mg, K and P levels improved at 30 t/ha, Na at 20 t/ha and Ca 40 t/ha of manure. Plant height and stem girth improved at 30 kg N/ha of fertilizer, however, nutrient levels for Ca, K and Mg decreased after the 1st harvest, while Na levels increased. Nutrient uptake was the highest for Mg and Na at 40 kg N/ha while for Ca at 30 kg N/ha of fertilizer. During the 2nd cycle plant height was the highest at 30 t/ha of manure, and effect of manure rate was significant (p<0.05) for number of leaves, plant height and biomass. Whereas, manure rate and biochar type effect were insignificant (p>0.05) for pH, Ec and nutrient uptake changes. Maize seedling showed significant response to fertilizer 40 kg N/ha for most of the growth parameters measured (P<0.05), except for germination percentage. All treatments investigated had no effect on germination percentage. The two biochar types showed significant (p<0.05) effects on soil pH and Ec. Drum biochar was slightly better performing than pit biochar. Results obtained from the various studies suggests that maize biochars derived from the pit and drum pyrolytic systems are potential soil amendments in correcting soil acidity and nutrient deficiency in the EC Province. Both biochar types have shown abilities to improve early maize growth and effectiveness of fertilizers in maize based systems of the EC Province. However, some variations in soil fertility and early maize growth were observed as a result of the soil type response towards the two biochar applications. This could also have risen as a result of a number of factors such as the nutritional composition of biochar material, initial soil type chemical composition, biochar and fertilizer application rates and time taken or period to complete each study. Therefore, further experiments should be conducted to validate these results, preferable having longer periods of study, moreover, field experiments. In addition, investigations on potential feedstock materials such as animal wastes used as biochar in the EC Province can be conducted.
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- Date Issued: 2017
Characterization of Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA) in selected recreational marine waters and beach sand in the Eastern Cape Province, South Africa
- Authors: Ankabi, Olufemi Emmanuel
- Date: 2017
- Subjects: Marine microbiology -- South Africa -- Eastern Cape Staphylococcus aureus infections -- South Africa -- Eastern Cape Pathogenic microorganisms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4992 , vital:28915
- Description: Staphylococcus aureus is a Gram-positive bacterium predominantly found on human skin and in nasal passages with 20 to 40 percent of the population carrying this organism. Although S. aureus is an unspectacular, non-motile coccoid bacterium, it is a perilous human pathogen associated with both nosocomial and community-acquired infections and it is increasingly becoming virulent and resistant to most antibiotics. It is responsible for several infections such as osteomyelitis, toxin-mediated diseases and bacteraemia, with severe infections arising from strains harbouring antibiotic resistance genes together with virulence genes. S. aureus has been largely confined to hospitals and long-term care facilities, but it is now emerging in the community in places such as recreational beach waters, and occurring in healthy individuals with no associated risk factors. This organism has been reported to be released by swimmers in beaches, suggesting that recreational waters are a potential source of community-acquired S. aureus infections. It is possibly the pathogen of greatest concern due to its intrinsic virulence, its capacity to cause various life-threatening infections, and its ability to adapt to varying environmental conditions. This study was aimed at characterizing S. aureus and methicillin-resistant S. aureus (MRSA) in Port Elizabeth, Port Alfred, Kenton-on-sea and East London beaches of the Eastern Cape Province of South Africa. This was done by investigating the occurrence, antibiotic susceptibilities, antibiotic-resistant genes and virulence genes profiles of S. aureus in the selected beaches. To achieve this aim, 249 beach sand and water samples were obtained from the beaches during the period of April 2015 to April 2016. Physico-chemical parameters of beach water was investigated on site using a multi-parameter ion specific meter during sample collection. Samples were filtered and inoculated on m-Endo agar, m-FC agar and bile aesculin azide agar for total and faecal coliform as well as Enterococci respectively. For isolation of S. aureus and MRSA, samples were cultured on Mannitol salt agar and Staph 24 agar. S. aureus was identified using morphological, Gram staining and molecular (PCR) methods. The isolates were further characterized by determining their antimicrobial resistance profiles, antibiotic resistant genes (mecA, rpoB, blaZ, ermB and tetK genes) and detection of virulent genes encoding intracellular adhesion (icaA), enterotoxin (seaA) and cytolytic toxins (PVL). The majority of study sites passed the directives of physico-chemical standards levels set by WHO during the study period. A total of 143 presumptive isolates were obtained of which 30 (30 percent) were confirmed as S. aureus with 22 (73.3 percent) of these confirmed isolates from marine water and 8 (26.7 percent) from marine sand. Upon culturing on MRSA 2 agar, 15 (50 percent) of isolates showed phonotypic resistance to methicillin. Based on Antimicrobial susceptibility tests, (22/30) 73.3 percent of the isolates showed phonotypic resistance to oxacillin. Out of the 30 isolates, 16 (53.3 percent) were mecA positive and were considered methicillin-resistant S. aureus. S. aureus showed high susceptibility to gentamycin, cefoxithin, levofloxacin, ciprofloxacin, imipenem, and chloramphenicol. A large proportion (36.67 percent to 96.7 percent) of the S. aureus isolates was resistant to penicillin G, ampicillin, oxacillin, tetracycline, clindamycin, rifampicin, vancomycin, sulfamethoxazole-Trimethoprim and erythromycin. Multiple antibiotic resistance (MAR) phenotypes were generated from 7 S. aureus isolates showing resistance to three or more antibiotics. The mecA, rpoB, blaZ, ermB and tetM genes coding for methicillin, rifampicin, βeta-lactam, erythromycin and tetracycline antibiotics resistance was detected in 5 (22.7 percent), 11 (45.8 percent), 16 (55.2 percent), 15 (71.4 percent) and 8 (72.7 percent) respectively. The PVL, icaA and seaA genes coding for virulent determinants were detected in 50, 20 and 13.3 percent of the confirmed isolates respectively. Physico-chemical and faecal indicator bacteria results obtained from this study can assist municipal authorities in developing appropriate management strategies for beaches in the study area. The findings of this study showed that the investigated beaches were contaminated with toxigenic and multi-drug resistant S. aureus strains. This emphasizes the need for the implementation of better control measures to reduce the occurrence of antibiotic resistant S. aureus and of virulent S. aureus strains in recreational waters. In our study it was established that the potential of recreational waters to be reservoirs of S. aureus should not be taken for granted, and it is important that beach goers be educated about this organism as well as other related pathogens that could affect human health, especially immuno-compromised individuals. The community should be educated on antibiotic stewardship and the detrimental effects of antibiotics abuse.
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- Date Issued: 2017
Characterization of the distribution of platinum group elements in sulphide ores within the Merensky Reef at Modikwa and Two Rivers Platinum Mines, Eastern Bushveld Complex, South Africa
- Authors: Zilibokwe, Nosibulelo Julie
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/7938 , vital:21326
- Description: The distribution of the platinum group element (PGE), in the Merensky Reef was characterized by, first determining the occurrence of the platinum group minerals (PGM), then by establishing the PGE concentration in the base metal sulphides (BMS) associated with the PGE mineralization in the Merensky Reef from selected borehole intersections, at the Two Rivers (TRP) and Modikwa Platinum Mines in the Eastern Bushveld Complex. A mineral liberation analyser (MLA) was then used to identify the PGM phases; their silicate and base metal associations; and their grain size distribution. Electron microprobe quantitative analysis and mapping were then used to determine the compositional variation of the PGM and the PGE elemental distribution in the BMS, respectively. The study showed that the BMS including pyrrhotite, pentlandite, and chalcopyrite were the principal sulphides, where pyrrhotite was most prominent with minor quantities of pyrite. Orthopyroxene, clinopyroxene and plagioclase were the most abundant primary silicate minerals identified, while secondary silicates identified included talc, serpentine and amphibole. Platinum group minerals showed three distinct groups with respect to the mineralogical association with the PGE; (i) BMS association; (ii) chromite association; and (iii) silicate association. Of the BMS, chalcopyrite showed the most dominant association with the PGMs. All samples from both mines exhibited a wide range of PGMs, including maslovite, braggite, cooperate, laurite and PGE alloys such as ferroplatinum as well as other unidentified platinum and palladium sulphides, arsenides and bismuthides, while gold was present as electrum. The PGMs ranged in size from less than a micron to about 125 microns with an average of 20 microns. The close association of PGM with BMS along the margins of sulphides indicates that the PGMs were derived from the sulphide melt. PGE distribution in the sulphides at Modikwa showed pentlandite contained the highest concentrations of palladium (up to 379 ppm) and chalcopyrite hosting the highest rhodium concentrations (up to 793 ppm). Samples from Two Rivers revealed pentlandite as the principal host to both palladium and rhodium, with concentrations reaching up to 695 and 930 ppm, respectively. Magnetite at both Modikwa and Two Rivers showed significant rhodium content, reaching up to 982 and 930 ppm, respectively. The pyrrhotite compared to other sulphides contained all the elements found in the platinum group (PPGE), namely, platinum, palladium and rhodium, with all the platinum identified found in the pyrrhotite. The concentrations for the iridium group (IPGE) namely, iridium, osmium, and ruthenium were below the detection limit. The PGE mineralization in the stratigraphy varied within each mine. The mineralization revealed top loading in the central sector (Modikwa) and bottom loading in the southern sector (Two Rivers). The sequence of the Merensky Reef at the two sectors of the Eastern Bushveld Complex showed a remarkable similarity in their mineralogy suggesting that these two sectors were formed from the same liquid or formed simultaneously within a single magma chamber; however the PGE distribution within the stratigraphy may have been controlled by the presence of cumulate sulphides.
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- Date Issued: 2017
Characterization of the Mitochondrial Plasmodium falciparum heat shock protein 70
- Authors: Nyakundi, David Onchong’a
- Date: 2017
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/44449 , vital:25408 , https://doi.org/10.21504/10962/44448
- Description: Malaria remains a global health problem and accounts for many deaths and illnesses in subSaharan Africa. Plasmodium falciparum, the causative agent of the most fatal form of malaria, expresses a repertoire of heat shock proteins for cytoprotection, survival and pathogenesis. The parasite genome encodes six Hsp70 proteins found in various cell compartments. However, the putative parasite mitochondrial Hsp70 (PfHsp70-3) has not been investigated. The J-proteins, Pfj1 and PFF1415c, were proposed to function as co-chaperones of PfHsp70-3. The biochemical characterization of PfHsp70-3 was initially complicated by the fact that the protein was insoluble when expressed in E. coli cells. Various approaches to solubilize it resulted in inactive protein. A general characteristic of eukaryotic mitochondrial Hsp70s is their insolubility and their reliance on an Hsp70 escort protein (Hep) for solubility and ultimate functions. In this study, a putative Hep protein was identified in the genome of P. falciparum that is referred to as PfHep1. Coexpression of PfHep1 with PfHsp70-3 resulted in soluble and biochemically active PfHsp70-3. Size exclusion chromatography was employed to separate PfHsp70-3 from PfHep1 after coexpression. PfHep1 suppressed thermally induced aggregation of PfHsp70-3 but not the aggregation of malate dehydrogenase or citrate synthase, thus showing specificity for PfHsp70-3. Zinc ions were also found to be essential for maintaining the functions of PfHep1, as EDTA chelation abrogated its abilities to suppress the aggregation of PfHsp70-3. Furthermore, PfHep1 did not stimulate the basal ATPase or increase refoldase activities of PfHsp70-3 hence displaying no co-chaperone roles. The full-length putative mitochondrial type I J protein, Pfj1, could not be produced in E.coli but a truncated protein containing the J-domain was produced which stimulated both the ATPase and refoldase activities of PfHsp70-3. Further, this study demonstrated that both PfHep1 and PfHsp70-3 localized to the mitochondrion in the erythrocytic stage of P. falciparum development thus confirming in silico predictions of their localization. Besides, PfHsp70-3 was expressed during all stages of the intraerythrocytic cycle of parasite development and was heat inducible. Generally, the data obtained in this study will enhance the existing knowledge on the biology of the parasite mitochondrial chaperone functions and open the possible avenue of drug targeting considering the specificity of PfHsp70- 3 and PfHep1 partnerships.
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- Date Issued: 2017
Chemical composition of leaf essential oils of Lantana camara varieties in South Africa and their effect on the behavioural preference of Falconia intermedia
- Authors: Ngxande-Koza, Samella W
- Date: 2017
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4877 , vital:20739
- Description: Lantana camara L. (Verbenaceae) is one the most problematic invaders in South Africa invading forest edges, sand dunes, and shorelines by forming impenetrable thickets. Lantana camara invasions degrade natural biodiversity, reduce the value of land and consequently it has been a target for biological control, over the last 50 years in South Africa. Studies that have reported on chemical profile of Lantana camara have been conducted around the world but not in South Africa. Hence, the first aim of the current study was to identify the chemical baseline of L. camara varieties in the Eastern Cape, South Africa. Recent studies have shown that feeding by one of the agents released against L. camara, Falconia intermedia (Distant) (Hemiptera: Miridae), induces anti-herbivory response through increased leaf toughness and trichome density. A preliminary study conducted also reported the production of volatile chemicals by one variety, Whitney Farm, due to feeding by the mirids. Therefore, the second aim was to determine the induced changes in chemical compounds of L. camara varieties after feeding by F. intermedia. A third aim was to determine the effect these chemical compounds have on the behaviour of F. intermedia. To identify the chemical baseline of L. camara varieties, the essential oils of four L. camara varieties (East London, Port Alfred, Whitney Farm and Heather Glen) were analysed using gas chromatography mass spectrometry (GC-MS) and that resulted to the identification of 163 constitutive and 75 induced chemicals across the varieties tested. Lantana camara varieties showed different chemical classes but were highly dominated by terpenes. A great variation in the number of constitutive chemical compounds was found in all the varieties. There were 56 constitutive chemical compounds in the Whitney Farm variety, 41 in the East London variety, 36 in the Heather Glen variety and 30 in the Port Alfred variety. The Whitney Farm variety had the highest number (22) of unique constitutive chemicals identified when compared with other varieties. This indicates the chemical distinctiveness of the Whitney Farm variety from the other varieties. In the varieties tested, there were common chemical compounds identified in constitutive and induced (discussed below) states of the plants such as caryophyllene, hexane, naphthalene, copaene and a-caryophyllene. Besides naphthalene, the majority of chemical compounds in South African L. camara varieties were similar to compounds that have been identified across the world, suggesting that they are closely related. The expression of naphthalene in these varieties may be due to changes in the chemicals expressed over evolutionary time as predicted by the Novel Weapons Hypothesis. Amongst the varieties, a great variation in chemical compounds and their concentrations was shown in the induced states of the plants. The concentration of constitutive caryophyllene ranged from (3.13 - 15.7) %, to (4.02 - 11.10) % after feeding. The concentration of constitutive hexane ranged from (6.13 - 71.19) %, to (33.3 - 75.8) % after feeding. The concentration of constitutive naphthalene ranged from (0.21 - 4.79) %, to (0.92 - 2.11) % after feeding. The concentration of constitutive copaene ranged from (0.57 - 1.57) %, to (1.20 - 2.72) %. Lastly, the concentration of constitutive a-caryophyllene ranged from (1.18 - 9.03) %, to (0.78 - 5.48) % after feeding. The changes in chemical concentrations in lantana varieties indicated that feeding by the mirid on L. camara varieties causes an induction by either reducing or increasing the chemical concentrations. To determine the effect of the identified compounds on the behaviour of F. intermedia adults, olfactometer bioassays were conducted using a Y-tube technique. A significantly higher proportion of F. intermedia were attracted to undamaged leaves over damaged leaves and purified air. Undamaged leaves attracted 52 % of F. intermedia from the East London variety, 62.5 % from the Port Alfred variety, 56 % from the Whitney Farm variety, 58 % from the Lyndhurst variety and 54.5 % from the Heather Glen variety in dual choice trials versus damaged leaves. Furthermore, a significantly higher proportion of F. intermedia were attracted to damaged leaves over purified air. Damaged leaves attracted 67 % of F. intermedia from the East London variety, 67 % from the Port Alfred variety, 65.9 % from the Whitney Farm variety, 65.3 % from the Heather Glen variety and 64.5 % from the Lyndhurst variety. Olfactometer bioassays were also conducted using purified standard compounds of four chemical compounds identified from essential oils, hexane was used as a positive control as it is reported to be an insect attractant in literature. Hexane was highly attractive to the mirids compared to three standard compounds caryophyllene, caryophyllene oxide and naphthalene at the rate of 80 %, 73 % and 80 %, respectively. The standard compounds tested against F. intermedia are major compounds contained by L. camara varieties and they have proven to have a repellent effect. This may indicate that after feeding by F. intermedia, the major compounds expressed by the plant varieties repel F. intermedia contributing to the invasiveness of this weed. The increased expression of hexane and caryophyllene after feeding may also indicate increased attraction to some insects, opening up the potential for third trophic level interactions in varieties where this is the case. This is the first study on the chemical composition of essential oils of L. camara in South Africa. Therefore, we recommend that where appropriate chemical profile studies of the invasive alien plants should be considered during host specificity testing, and the vital role of chemical compounds on agent-weed interactions must be taken into consideration with other factors before and after the biological control agents are released.
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- Date Issued: 2017
Comparative localization studies of P.falciparum ADP-ribosylation factor proteins in P.falciparum parasites and hela cells using GFP tagged constructs
- Authors: Swart, Tarryn
- Date: 2017
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3537 , vital:20519
- Description: Expected release date-December 2018
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- Date Issued: 2017
Comparative studies of different ant-hypertensive treatments used for cardiovascular disease patients : a case study of public health facility in the Eastern Cape South Africa
- Authors: Abiodun, Oluwatoyin Victoria
- Date: 2017
- Subjects: Survival analysis (Biometry) Cardiovascular system -- Diseases
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/13205 , vital:39519
- Description: Discovery has shown that many deaths arising from cardiovascular disease often show early symptoms of high blood pressure, which makes it the leading risk factor of cardiovascular diseases. There is a distressing rate of 970 million hypertensive patients worldwide, a higher ratio of 640 million are from developing countries, if proper measures are not taken, there will be a higher growth of cardiovascular disease in adults by 2025. The focus of this study was to compare the therapeutic potentials of the anti-hypertensive therapies, drug A (amiloride + furosemide) and drug B (hydrochlorothiazide + enalapril) used in the treatment of cardiovascular disease patients for their capability to lengthen remission duration and survival time. All patients were diagnosed with a type of cardiovascular disorder, therefore patient records were followed up and blood pressure was being monitored for a period of two years. The retrospective data gotten from the public health facility was analysed using survival analysis methods. The results revealed that there was no statistical significance in the distributions of the length of remission and survival time of drug A and drug B patients. Also, in the age category, CVD patients that are 55 and above recover faster with drug A, while CVD patients below 55 shows a better survival with drug B. Then again, estimates from the gender category show a better survival in males using drug A, while the females thrive slightly better using drug B. Among all the risk factors considered in the study, only employment status showed a strong impact on survival time (remission). The findings from this study may help to formulate interventions and strategies that will increase the lifespan of cardiovascular patients and reduce early mortality due to cardiovascular diseases.
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- Date Issued: 2017
Computational design of a smart and efficient control system for a residential air source heat pump water heater
- Authors: Yongoua Nana Joel
- Date: 2017
- Subjects: Heat pumps -- Specifications Water heaters Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4582 , vital:28435
- Description: An air source heat pump (ASHP) water heater is a renewable and energy efficient hot water heating technology. ASHP water heaters are fast gaining maturity in the South African market and in Africa at large due to their low energy consumption (about 67 percent lower than conventional geysers), relatively low installation and operation cost, their environmental friendly nature and possibly the ease to retrofit with the old inefficient technologies. Furthermore, ASHP water heaters make use of some of the most recent advancement in refrigeration technologies enhancing their performance through a wide range of weather conditions. However, residential ASHP water heaters which come at the tail of a series of highly sophisticated models still harbour primitive control designs. One of such control system is the intermittent (on/off) control whereby the ASHP unit responds to a temperature differential threshold rather than instantaneous temperature fluctuations. Unfortunately, this control method contributes to a rapid deterioration of the compressor and other actuators due to high starting current during transient states and partial loading. Capacity control is a better alterative as it offers a more reliable system’s performance as well as a better protection for the system components. However, the drawbacks of implementing such a technology on residential ASHP water heaters is the initial purchasing cost. We use a systematic approach in this research to circumvent the purchasing cost and complete redesign hysteresis. The first step was centered around a hypothetical analysis of the performance of the heat exchangers in a bid to uncover the weakness during the operation of a residential ASHP water heater. It was observed that at ambient temperatures above 22°C notably during summer and winter afternoons, water only harnesses about 75 percent of the total heat rejected. Furthermore, the actuators keep doing work for about 15-20 minutes even after the heat transfer process has ceased completely. Following these observations, a sequential flow algorithm was developed aimed at matching the consumption point to weather variables like ambient temperature and secondly to most efficiently synchronize actuator components for a better energy management. This novel control method can save up to 58 percent of energy compared to the conventional on/off method during summer afternoons and averagely 20 percent during the rest of the day. It also has the merit to be cost effective as it barely requires no component retrofitting.
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- Date Issued: 2017
Consumers' attitudes towards ready-to-eat fast-food products and their relationship with obesity in Mdantsane township in the Eastern Cape Province, South Africa
- Authors: Matyolo, Pamela
- Date: 2017
- Subjects: Obesity -- South Africa -- Eastern Cape Obesity
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9022 , vital:34183
- Description: The South African fast-food industry has experienced substantial recent growth. However, as consumers have incorporated more fast food into their daily diets, obesity has become a major problem. The aggressive marketing techniques of fast food firms coupled with the busy urban lifestyle have significant implications for dietary health habits. The study aimed at investigating consumers’ attitudes towards fast food and the relationship between fast food consumption and obesity. The field survey design of the study employed a mixed-methods approach involving the use of a semi-structured questionnaire. The study was limited to the Mdantsane Township located in the Eastern Cape Province of South Africa. A quota sample of 200 respondents (n = 200) was selected from which data were collected using a self-administered questionnaire. Descriptive results revealed that the participants had positive attitudes towards fast foods. Although they agreed that eating fast foods increased body weight, the participants mostly did not feel overweight or obese. The participants were well aware of the negative health implications of excessive fast food consumption. This knowledge generally did not deter their positive fast food attitudes, although participants expressed their desire for additional healthier fast food options in the market. Regression estimates further revealed that carbohydrate and starchy type of fast foods (𝑃 < 0.01), other sources of fast foods (𝑃 < 0.05), age group, physical appearance and meaty type of fast foods (𝑃 < 0.10) had significant influence on the frequency of fast food consumption. The results further revealed that physical appearance (𝑃 < 0.01), religion (𝑃 < 0.05), age group and supermarkets and source of fast foods (𝑃 < 0.1) had significant influence on respondents’ BMI scores. The study concludes that there exist socio-economic and institutional factors that have considerable bearing on consumers’ fast food consumption and BMI scores. The study advocates for public health policy making concerning awareness of the negative health consequences of fast food consumption targeting mostly young adult females who mainly purchase in franchises and supermarkets with a high meaty diet.
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- Date Issued: 2017
Cultural and heritage tourism trends in the Amathole District Municipality of the Eastern Cape Province, South Africa, 2004-2014
- Authors: Mboniswa, Mncedi Justice
- Date: 2017
- Subjects: Heritage tourism -- South Africa -- Eastern Cape Cultural property -- Repatriation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7897 , vital:30798
- Description: The promotion of tourism in a country, especially those with high levels of poverty is one of the strategies that can potentially improve socio-economic conditions of citizens. In South Africa, cultural and heritage tourism is seen as one of the ways in which cultural resources can be utilised to benefit marginalised communities and individuals. Such resources can also serve as source of income since both domestic and international tourists can activate industry as they are interested in learning more about other cultures and heritage. There are on-going debates, however on what constitutes cultural and heritage tourism, who it benefits and how this enterprise is located within various communities of South Africa. This research therefore aims to fill this gap through investigating cultural and heritage tourism development trends within the Amathole District Municipality (ADM) and how this development trend impacts on employment creation and improving the socio-economic conditions of citizens within this area of ADM. To realise this aim, the study looks at the availability of cultural and heritage tourism structures within the ADM and the database records on these structures. This study adopts the community benefit tourism initiatives approach to tourism development in the Amathole District Municipality of the Eastern Cape Province. This qualitative study reveals how the community benefit tourism approach encompasses rewards to local communities, in as much as it enhances sustainability of tourism initiatives. In bringing out these aspects, the study also examines efforts of the government and private sector in the up-keeping of tourism initiatives, especially for marginalised communities of South Africa.
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- Date Issued: 2017
Density-dependent effects on body size, Philopatry, and dispersal in the Damaraland mole-rat (Fukomys damarensis)
- Authors: Finn, Kyle T
- Date: 2017
- Subjects: Fukomys damarensis , Fukomys damarensis -- Reproduction , Fukomys damarensis -- Growth , Rodents -- Reproduction -- South Africa -- Northern Cape , Rodents -- Growth -- South Africa -- Northern Cape , Rodent populations -- South Africa -- Northern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/50495 , vital:25993
- Description: Population density may exert changes in a variety of behavioural and physiological characters in animals. However, the effects of density-dependence and dispersal are poorly studied in subterranean rodents due to the difficulties involved in observing such effects in wild populations. Using the cooperative breeding Damaraland mole-rat (Fukomys damarensis) as a model species, the effects of population density on body size, growth rates, group size, recruitment, philopatry and dispersal were investigated at two sites (one with low density and one with high density) in the Northern Cape of South Africa. Group size, litter size and the probability of recapture were independent of population density. However, individual body size, recruitment, dispersal rate and dispersal distance were density-dependent. Individuals were significantly larger, juveniles exhibited a significantly higher growth rate, and juvenile recruitment was significantly greater when population density was low. At higher densities, significantly more individuals were lost between capture events which may be indicative of increased rates of dispersal. Mean dispersal distances in mole-rats were reduced at higher densities and increased at lower densities. While both sexes dispersed equally, males were significantly more likely to join an established colony and females created new burrow systems. In addition, four times as many single females were found when population density was low. The apparent differences in the study populations may be attributed to variable annual rainfall or food availability. The greater annual rainfall at the high-density site may provide better habitat conditions and therefore result in an increase in the population density and an increased dispersal rate due to the relaxed ecological constraints such as reduced energetic costs to burrowing. However, the larger body size found at the low-density site may indicate that the available food at that location is of better quality. This study revealed that mole-rats were able to disperse over 1km and therefore a much larger study area would be required in capture-mark-recapture studies to ensure the recapture of the majority of dispersers. Lastly, a surprising find of this study was that females may survive a solitary existence for over two years while awaiting the arrival of a mate.
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- Date Issued: 2017
Design, construction and performance evaluation of an agitated portable biogas digester under greenhouse-regulated temperature
- Authors: Mutungwazi Asheal
- Date: 2017
- Subjects: Sewage -- Purification -- Anaerobic treatment Green technology Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9055 , vital:34222
- Description: Biogas yield in anaerobic digesters is negatively affected by low temperatures during cold seasons and nights, temperature fluctuations and inefficient agitation. Electrical heating and underground digester installations have been used to help minimise these effects but the high cost of electrical heating, infeasibility of underground installations in some terrains, inefficient agitation and difficult maintenance continue to be major set-backs to high biogas yields. In this study a 100 ℓ, agitated, portable carbon steel digester housed within a greenhouse, whose operation temperature is automatically maintained at an optimum of 35 ± 1 oC by means of an ON/OFF electronic circuit for ventilation control through a suitably sized window and insulation offered by an air film trapped in-between a double layer of polyethylene plastic covering of the greenhouse, was designed. Cow dung from a dairy farm at the University of Fort Hare with total solids (TS), volatile solids (VS), chemical oxygen demand (COD) and ammonia nitrogen content of 162348.67 mg/ℓ, 116543.98 mg/ℓ, 37 879 mg/ℓ and 128 - 235 mg/ℓ respectively was used for the performance evaluation of the digester. Analysis of the biogas produced starting from day 6 of the 31-day retention period showed a specific biogas yield of 0.036 m3/kgVSadded and a methane yield of 55percent. The optimum pH maintained was 7.2 and the COD reduction achieved during the digestion period was 61percent. This simple, easy to construct, inexpensive yet efficient design will lead to improved biogas yields and quality and faster dissemination of the biogas technology.
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- Date Issued: 2017
Detection and antibiogram profile of members of the vibrio species in Umzimvubu, Swartkops and Buffalo rivers the Eastern Cape province, South Africa
- Authors: September, Dolly Thandeka
- Date: 2017
- Subjects: Vibrio -- South Africa -- Eastern Cape Water -- Fluoridation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/15221 , vital:40255
- Description: Freshwaterbodies are often recipients of a wide array of infectious agents yet they serve as immediate sources of water supply. Brackish and freshwater rivers support the growth of Vibrio species, which are the leading cause of diarrheal infections in the world. Their occurrence in these environments is detrimental to the health and well-being of many communities. Hence, this study aimed at assessing the occurrence and antibiogram profile of Vibrio species in Swartkops, UMzimvubu and Buffalo rivers. The rivers are important sources of freshwater supplies for some communities around the Eastern Cape Province, and water samples were collected once off from each of the sites, using standard membrane filtration method to concentrate the samples. Cultivation was carried out on Thiosulfate Citrate-Bile Salt Sucrose (TCBS) agar, were typical yellow/green colonies were enumerated as presumptive Vibrio species and expressed as CFU/100mL. Presumptive Vibrio counts ranged from 0 to 1.67 × 103 CFU/100mL, 0 to 6.42 ×102 CFU/100mL and 0 to 3.28×103 CFU/100ml in the uMzimvubu, Swartkops and Buffalo rivers respectively. Polymerase Chain Reaction was employed for molecular identification of the Vibrio isolates. Two hundred (200) presumptive Vibrio species were screened for molecular identification, and 185 isolates confirmed positive as belonging to the Vibrio genus. Antibiotic susceptibility profile of the confirmed isolates was determined using a panel of 12 commercial test antibiotics. All the confirmed Vibrio species showed 98 to 100percent multiple antibiotic resistance against all the test antibiotics from the three study sites. The most predominant phenotypic pattern of multidrug resistance displayed by the isolates was CAZ-PEN-AMP-CIP-AK-AZM-TET-CAM-CTX-STX-GEN-IPM showing 100percent resistance to all 12 antibiotics. The multiple antibiotic resistance index (MARI) on average was 1 for all the three rivers assessed. This finding suggest high possibility of antibiotic pollution and usage around the study areas, and occurrence of potentially pathogenic Vibrio species carrying antibiotic resistant genes, which is a major public and environmental health concern.
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- Date Issued: 2017
Determination of physiochemical properties and metal levels in soil, water, and plant from Alice landfill site
- Authors: Maphuhla, N G
- Date: 2017
- Subjects: Heavy metals -- Environmental aspects Soil pollution Water -- Pollution
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6224 , vital:29521
- Description: The state of soil is of great significance because it is a common medium for plant growth, which provides important nutrients to plants. Water pollution is the build-up of harmful substances in water bodies to the level that results in health problems for people and animals. Heavy metal pollution (of soil, water, and plants) and their health effects on people is a persistent social issue, and several types of research have recognized health risks of residents living close to open dumpsites. Dump sites are sources of heavy metal impurity and toxicity to the surrounding environment. Analyses were done on water and soil samples for temperature, pH, Electrical conductivity (EC), Total dissolved solids (TDS), alkalinity, organic matter, organic carbon and total hardness. The pH results range from slightly acidic (6.79) to neutral soil pH (7.09), and have been recorded within the normal range from WHO. All the determined physicochemical properties in soil and water have been recorded within the normal range, except for EC in water which was found to be above the permissible limits by WHO. The heavy metals concentration was determined using the AAS technique. The results obtained shows that the dumpsite‘s soil consists of high metal concentration when compared to control site. The concentration in dumpsites ranges between 1.2783 ± 0.83 mg/kg to 26.3213 ± 6.37 mg/kg. The descending order for selected metal concentrations were in this following order Mn> Cu>Hg>Pb. The Pb and Hg mean concentration was recorded above permissible limits, while the Mn and Cu were within the normal range suggested by WHO. In both water and Acacia karroo samples the Cu was not detected. The trend of metal concentration in water sample was found to be in this order Hg> Mn > Pb> Cu, while in Acacia karroo metal concentration is Hg> Mn> Pb> Cu. The one-way ANOVA test was used to compare the mean concentration of selected metals in each sampling site. The results show that there is a statistically significant difference between the mean concentrations of selected metals; this is supported by the value of F-static and p-value (p <0.05)
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- Date Issued: 2017
Determining and analysing the emergent behaviour from context-aware devices
- Authors: Bandason, Vivian
- Date: 2017
- Subjects: Context-aware computing Mobile computing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/7907 , vital:30805
- Description: With the continued miniaturization of technology and the incorporation of Moore’s law, smartphones are more powerful. These mobile devices contain technologies that add other functionalities to them. Technologies such as sensors constantly provide information to the device. The constant stream of information from these sensors often leads to information overload of relevant and irrelevant information. To work towards solving this problem context-aware computing was introduced. Our major concern is that context information in context aware computing is not completely being utilized. The aggregation of context information could unlock more possibilities. This research seeks to aggregate the context of multiple devices such that, through analysis, some emergent behaviour can be observed. In this research context information from the sensors of devices is collected using an Android application and a central Server. The context information is used for pattern analysis. A pattern analysis algorithm is designed and used to observe patterns throughout the data set. It shows patterns that are similar within the dataset. In the case that the pattern observed has no similar pattern or few similar patterns this behaviour can be stated as emergent in the dataset. Further study of this emergent behaviour can be performed were a classifier can be used to give the exact activities that were being performed at that time. The research found this was possible and has many uses. One of these is in disaster prevention were the behaviour of a group of individuals may be monitored to observe any random changes such as masses running at the same time. This could be used as a first warning to natural disasters.
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- Date Issued: 2017
Development and validation of an In Vitro Release Test (IVRT) to investigate the release of miconazole nitrate from topical cream formulations
- Authors: Purazi, Potiwa
- Date: 2017
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/65223 , vital:28711
- Description: Expected release date-May 2019
- Full Text:
- Date Issued: 2017