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  • Pretoria, South Africa
As stated by Dow, ‘this commodity clearance application is to support the potential shortage of soybean in South Africa and the subsequent need to import grain from exporting countries that may be commercially growing DAS-68416-4 and... more
As stated by Dow, ‘this commodity clearance application is to support the potential shortage of soybean in South Africa and the subsequent need to import grain from exporting countries that may be commercially growing DAS-68416-4 and other genetically modified soybean (p.87)’. This is mainly to feed South Africa’s rapidly growing poultry industry. Despite a huge increase in domestically produced soybean in recent years (from 100,000ha cultivated in 1999 to 418,000ha in 2011), production costs (including feed) are squeezing the margins of many domestic producers. A recent, well publicised trade spat with Brazilian poultry producers highlights this (ACB, 2011). The underlying purpose is to open markets for a new generation of herbicide tolerant crops that have been developed in the United States in response to an epidemic of glyphosate tolerant weeds. This will be expanded upon below.
The effective and accurate assessment of the total microbial community diversity is one of the primary challenges in modem microbial ecology, especially for the detection and characterization of unculturable populations and populations... more
The effective and accurate assessment of the total microbial community diversity is one of the primary challenges in modem microbial ecology, especially for the detection and characterization of unculturable populations and populations with a low abundance. Accordingly, this study was undertaken to investigate the diversity of the microbial community during the biodegradation of cis- and trans-dichloroethenes in soil and wastewater enrichment cultures. Community profiling using PCR targeting the 16S rRNA gene and denaturing gradient gel electrophoresis (PCR-DGGE) revealed an alteration in the bacterial community profiles with time. Exposure to cis- and trans-dichloroethenes led to the disappearance of certain genospecies that were initially observed in the untreated samples. A cluster analysis of the bacterial DGGE community profiles at various sampling times during the degradation process indicated that the community profile became stable after day 10 of the enrichment. DNA sequenc...
Copyright: 2018, Pretoria: Human Sciences Research Council, also the Africa Institute of South Africa. Due to copyright restrictions, the attached PDF file only contains the pre-print version of the full-text item. For access to the... more
Copyright: 2018, Pretoria: Human Sciences Research Council, also the Africa Institute of South Africa. Due to copyright restrictions, the attached PDF file only contains the pre-print version of the full-text item. For access to the full-text item, please consult the publisher's website.
Renewable Energy Technologies are rapidly gaining uptake in South Africa, already having more than 3900 MW operational wind, solar PV, Concentrating Solar Power (CSP) and biogas capacity. CSP has the potential to become a leading... more
Renewable Energy Technologies are rapidly gaining uptake in South Africa, already having more than 3900 MW operational wind, solar PV, Concentrating Solar Power (CSP) and biogas capacity. CSP has the potential to become a leading Renewable Energy Technology, as it is the only one inherently equipped with the facility for large-scale thermal energy storage for increased dispatchability. There are many studies that aim to determine the potential for CSP development in certain regions or countries. South Africa has a high solar irradiation resource by global standards, but few studies have been carried out to determine the potential for CSP. One such study was conducted in 2009, prior to any CSP plants having been built in South Africa. As part of a broader study to determine the impact of CSP on South Africa’s water resources, a geospatial approach was used to optimise this potential based on technological changes and improved spatial data. A tiered approach, using a comprehensive set...
A systematic approach to evaluate Concentrating Solar Power (CSP) plant fleet deployment and sustainable water resource use in arid regions is presented. An overview is given of previous work carried out. Once CSP development scenarios,... more
A systematic approach to evaluate Concentrating Solar Power (CSP) plant fleet deployment and sustainable water resource use in arid regions is presented. An overview is given of previous work carried out. Once CSP development scenarios, suitable areas for development, and the water demand from CSP operations were evaluated, appropriate spatiotemporal CSP performance models were developed. The resulting consumptive patterns and the impact of variable resource availability on CSP plant operation are analysed. This evaluation considered the whole of South Africa, with focus on the areas identified as suitable for CSP, in order to study the impact on local water resources. It was found that the hydrological limitations imposed by variable water resources on CSP development are severe. The national annual theoretical net generation potential of wet-cooled Parabolic Trough decreased from 11,277 to 120 TWh, and that of wet-cooled Central Receiver decreased from 12,003 to 170 TWh. Dry coole...
Copyright: 2017 Wiley. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website.
South Africa has experienced great uncertainty in its electricity supply sector. Many energy system modeling efforts have been undertaken. This is to determine the most appropriate energy mix and manage uncertainty. We review all... more
South Africa has experienced great uncertainty in its electricity supply sector. Many energy system modeling efforts have been undertaken. This is to determine the most appropriate energy mix and manage uncertainty. We review all available, relevant studies and summarize their results, modeling approaches, and input assumptions. From this, we try to understand their impact on CSP development in South Africa.
The Bacillus licheniformis ydaP gene encodes for a pyruvate oxidase that catalyses the oxidative decarboxylation of pyruvate to acetate and CO. The YdaP form of this enzyme was purified about 48.6-folds to homogeneity in three steps. The... more
The Bacillus licheniformis ydaP gene encodes for a pyruvate oxidase that catalyses the oxidative decarboxylation of pyruvate to acetate and CO. The YdaP form of this enzyme was purified about 48.6-folds to homogeneity in three steps. The enzyme was recovered in a soluble form and demonstrated significant activity on pyruvate using 2, 6-dichlorophenolindophenol (DCPIP) as an artificial electron acceptor. HPLC analysis of the YdaP-enzyme catalysed conversion of pyruvate showed acetate as the sole product, confirming the putative identity of pyruvate oxidase. Analysis of the substrate specificity showed that the YdaP enzyme demonstrated preference for short chain oxo acids; however, it was activated by 1% Triton X-100. The YdaP substrate-binding pocket from the YdaP protein differed substantially from the equivalent site in all of the so far characterized pyruvate oxidases, suggesting that the B. licheniformis YdaP might accept different substrates. This could allow more accessibility ...
The effective and accurate assessment of the total microbial community diversity is one of the primary challenges in modem microbial ecology, especially for the detection and characterization of unculturable populations and populations... more
The effective and accurate assessment of the total microbial community diversity is one of the primary challenges in modem microbial ecology, especially for the detection and characterization of unculturable populations and populations with a low abundance. Accordingly, this study was undertaken to investigate the diversity of the microbial community during the biodegradation of cis- and trans-dichloroethenes in soil and wastewater enrichment cultures. Community profiling using PCR targeting the 16S rRNA gene and denaturing gradient gel electrophoresis (PCR-DGGE) revealed an alteration in the bacterial community profiles with time. Exposure to cis- and trans-dichloroethenes led to the disappearance of certain genospecies that were initially observed in the untreated samples. A cluster analysis of the bacterial DGGE community profiles at various sampling times during the degradation process indicated that the community profile became stable after day 10 of the enrichment. DNA sequenc...
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It is now widely accepted that the application of standard microbiological methods for the recovery of microorganisms from the environment has had limited success in providing access to the true extent of microbial biodiversity. It... more
It is now widely accepted that the application of standard microbiological methods for the recovery of microorganisms from the environment has had limited success in providing access to the true extent of microbial biodiversity. It follows that much of the extant microbial genetic diversity (collectively termed the metagenome) remains unexploited, an issue of considerable relevance to a wider understanding of microbial communities and of considerable importance to the biotechnology industry. The recent development of technologies designed to access this wealth of genetic information through environmental nucleic acid extraction has provided a means of avoiding the limitations of culture-dependent genetic exploitation.
A complex of non-covalently bound polypeptides is located on the surface of the merozoite form of the human malaria parasite Plasmodium falciparum. Four of these polypeptides are derived by proteolytic processing of the merozoite surface... more
A complex of non-covalently bound polypeptides is located on the surface of the merozoite form of the human malaria parasite Plasmodium falciparum. Four of these polypeptides are derived by proteolytic processing of the merozoite surface protein 1 (MSP-1) precursor. Two components, a 22 and a 36 kDa polypeptide are not derived from MSP-1. The N-terminal sequence of the 36 kDa polypeptide has been determined, the corresponding gene cloned, and the protein characterised. The 36 kDa protein consists of 211 amino acids and is derived from a larger precursor of 371 amino acids. The precursor merozoite surface protein 6 (MSP-6) has been designated, and the 36 kDa protein, MSP-6(36). Mass spectrometric analysis of peptides released from the polypeptide by tryptic digestion confirmed that the gene identified codes for MSP-6(36). Antibodies were produced to a recombinant protein containing the C-terminal 45 amino acid residues of MSP-6(36). In immunofluorescence studies these antibodies bound to antigen at the parasite surface or in the parasitophorous vacuole within schizonts, with a pattern indistinguishable from that of antibodies to MSP-1. MSP-6(36) was present in the MSP-1 complex immunoprecipitated from the supernatant of in vitro parasite cultures, but was also immunoprecipitated from this supernatant in a form not bound to MSP-1. Examination of the MSP-6 gene in three parasite lines detected no sequence variation. The sequence of MSP-6(36) is related to that of the previously described merozoite surface protein 3 (MSP-3). The MSP-6(36) amino acid sequence has 50% identity and 85% similarity with the C-terminal region of MSP-3. The proteins share a specific sequence pattern (ILGWEFGGG-[AV]-P) and a glutamic acid-rich region. The remainder of MSP-6 and MSP-3 are unrelated, except at the N-terminus. Both MSP-6(36) and MSP-3 are partially associated with the parasite surface and partially released as soluble proteins on merozoite release. MSP-6(36) is a hydrophilic negatively charged polypeptide, but there are two clusters of hydrophobic amino acids at the C-terminus, located in two amphipathic helical structures identified from secondary structure predictions. It was suggested that this 35 residue C-terminal region may be involved in MSP-6(36) binding to MSP-1 or other molecules; alternatively, based on the secondary structure and coil formation predictions, the region may form an intramolecular anti-parallel coiled-coil structure.
The combined effects of climate change, the continued volatility of fuel prices, the recent food crisis and global economic turbulence have triggered a sense of urgency among policymakers, industries and development practitioners to find... more
The combined effects of climate change, the continued volatility of fuel prices, the recent food crisis and global economic turbulence have triggered a sense of urgency among policymakers, industries and development practitioners to find sustainable and viable solutions in the area of biofuels. This sense of urgency is reflected in the rapid expansion of global biofuels production and markets over
The Cape Floral Kingdom is an area of unique plant biodiversity in South Africa with exceptional concentrations of rare and endemic species and experiencing drastic habitat loss. Here we present the first molecular study of the microbial... more
The Cape Floral Kingdom is an area of unique plant biodiversity in South Africa with exceptional concentrations of rare and endemic species and experiencing drastic habitat loss. Here we present the first molecular study of the microbial diversity associated with the rhizosphere soil of endemic plants of the Proteaceae family (Leucospermum truncatulum and Leucadendron xanthoconus). Genomic DNA was extracted from L. truncatulum rhizosphere soil, L. xanthoconus rhizosphere and non-rhizosphere soil and used as a template for the polymerase chain reaction (PCR) amplification of the 16S ribosomal RNA gene (rDNA). Construction and sequencing of 16S rDNA libraries revealed a high level of biodiversity and led to the identification of several novel bacterial phylotypes. The bacterial community profiles were compared by 16S rDNA denaturing gradient gel electrophoresis (DGGE). Cluster analysis and biodiversity indices revealed that the rhizosphere soil samples were more similar to each other than to non-rhizosphere soil and the rhizosphere soil contained a bacterial diversity that was richer and more equitable compared with non-rhizosphere soil. A Chloroflexus and an Azospirillum genospecies were restricted to the L. xanthoconus rhizosphere soil and Stenotrophomonas genospecies was identified in all rhizosphere soil samples but was not present in the non-rhizosphere soil. Taxon-specific nested PCR and DGGE-identified differences between the Proteaceae plant rhizosphere soil with a Frankia genospecies restricted the L. truncatulum rhizosphere. Archaea-specific rDNA PCR, DGGE and DNA sequencing revealed that Crenarcheote genospecies were excluded from the plant rhizosphere soil and only present in non-rhizosphere soil.
A complex of non-covalently bound polypeptides is located on the surface of the merozoite form of the human malaria parasite Plasmodium falciparum. Four of these polypeptides are derived by proteolytic processing of the merozoite surface... more
A complex of non-covalently bound polypeptides is located on the surface of the merozoite form of the human malaria parasite Plasmodium falciparum. Four of these polypeptides are derived by proteolytic processing of the merozoite surface protein 1 (MSP-1) precursor. Two ...
... in DiVA. Create reference ». Author: Sjöling, Sara (Södertörn University College, School of Life Sciences). Stafford, W. Cowan, DA. Title: Soil metagenomics: exploring and exploiting the soil microbial gene pool. Department: Södertörn... more
... in DiVA. Create reference ». Author: Sjöling, Sara (Södertörn University College, School of Life Sciences). Stafford, W. Cowan, DA. Title: Soil metagenomics: exploring and exploiting the soil microbial gene pool. Department: Södertörn University College, School of Life Sciences. ...
The Cape Floral Kingdom is an area of unique plant biodiversity in South Africa with exceptional concentrations of rare and endemic species and experiencing drastic habitat loss. Here we present the first molecular study of the microbial... more
The Cape Floral Kingdom is an area of unique plant biodiversity in South Africa with exceptional concentrations of rare and endemic species and experiencing drastic habitat loss. Here we present the first molecular study of the microbial diversity associated with the rhizosphere soil of endemic plants of the Proteaceae family (Leucospermum truncatulum and Leucadendron xanthoconus). Genomic DNA was extracted from L. truncatulum rhizosphere soil, L. xanthoconus rhizosphere and non-rhizosphere soil and used as a template for the polymerase chain reaction (PCR) amplification of the 16S ribosomal RNA gene (rDNA). Construction and sequencing of 16S rDNA libraries revealed a high level of biodiversity and led to the identification of several novel bacterial phylotypes. The bacterial community profiles were compared by 16S rDNA denaturing gradient gel electrophoresis (DGGE). Cluster analysis and biodiversity indices revealed that the rhizosphere soil samples were more similar to each other than to non-rhizosphere soil and the rhizosphere soil contained a bacterial diversity that was richer and more equitable compared with non-rhizosphere soil. A Chloroflexus and an Azospirillum genospecies were restricted to the L. xanthoconus rhizosphere soil and Stenotrophomonas genospecies was identified in all rhizosphere soil samples but was not present in the non-rhizosphere soil. Taxon-specific nested PCR and DGGE-identified differences between the Proteaceae plant rhizosphere soil with a Frankia genospecies restricted the L. truncatulum rhizosphere. Archaea-specific rDNA PCR, DGGE and DNA sequencing revealed that Crenarcheote genospecies were excluded from the plant rhizosphere soil and only present in non-rhizosphere soil.
It is now widely accepted that the application of standard microbiological methods for the recovery of microorganisms from the environment has had limited success in providing access to the true extent of microbial biodiversity. It... more
It is now widely accepted that the application of standard microbiological methods for the recovery of microorganisms from the environment has had limited success in providing access to the true extent of microbial biodiversity. It follows that much of the extant microbial genetic ...
Ammonia-oxidizing bacteria (AOB) are essential in the biogeochemical cycling of nitrogen as they catalyze the rate-limiting oxidation of ammonia into nitrite. Since their first isolation in the late 19th century, chemolithoautotrophic... more
Ammonia-oxidizing bacteria (AOB) are essential in the biogeochemical cycling of nitrogen as they catalyze the rate-limiting oxidation of ammonia into nitrite. Since their first isolation in the late 19th century, chemolithoautotrophic AOBs have been identified in a wide range of natural (e.g., soils, sediments, estuarine, and freshwaters) and man created or impacted habitats (e.g., wastewater treatment plants and agricultural soils). However, little is known on the plant-species association of AOBs, particularly in the nutrient-starved fynbos terrestrial biome. In this study, we evaluated the diversity of AOBs in the plant canopy of three South African fynbos-specific plant species, namely Leucadendron xanthoconus, Leucospermum truncatulum and Leucadendron microcephalum, through the construction of amoA-gene clone libraries. Our results clearly demonstrate that plant-species specific and monophyletic AOB clades are present in fynbos canopy soils.
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