Magister Scientiae - MSc (Biochemistry)
http://hdl.handle.net/11394/3178
2024-03-29T11:25:18ZThe adenomatous polyposis coli (APC) and p53 gene status in South African oesophageal cancer patients
http://hdl.handle.net/11394/10321
The adenomatous polyposis coli (APC) and p53 gene status in South African oesophageal cancer patients
Skelton, Michelle
Oesophageal cancer is the most conmon cause of cancer-related deaths in black males in South Africa. In an effort to understand the molecular nature of oesophageal carcinogenesis in South Africa, two tumour suppressor genes, Adenomatous Polyposis Coli (APC) and p53, were examined in normal and tumour tissue obtained from 33 oesophageal cancer patients. Several studies have shown that alterations of the APC and p53 genes are associated with the development of cancer. Allelic loss at the APC gene locus was examined using two polymorphic markers within the coding region of the APC gene. Single stranded conformation polymorphism, heteroduplex and DNA sequencing analyses were used to detect mutations in the mutation susceptible regions of the APC and p53 genes. The "Mutation Cluster Region" (MCR) in exon 15 of the APC gene was examined. Only exons 5 and 6 in the "hot spot" region of the p53 gene were examined. An allelic loss of 21% (4 of 19 informative cases) and an informativity of 59Yo (19 of 32) of the APC gene was demonstrated in patients analysed. No somatic mutations were detected in the MCR in exon 15 of the APC gene. Three putative mutations were detected in the p53 gene using SSCP and HD analysis, two of which were confirmed by DNA sequencing. Analysis of one patient revealed a TCA to TGA base substitution at codon 183 in exon 5 of the p53 gene, resulting in a stop codon at that position. An eleven base pair deletion in exon 6 of the p5 3 gene was detected in another patient. This deletion caused a frame shift mutation and culminated in a premature stop codon 13 codons downstream. Overall, a mutation frequency of 8% (2 of 25 patients analysed) was detected for the p53 gene with exons 7 and 8 still pending further study. These results suggest that the APC gene may not be involved in oesophageal cancer in South Africa and further studies are necessary in order to examine the role of thep53 gene in this disease in South Africa.
>Magister Scientiae - MSc
1996-01-01T00:00:00ZIsolation and Partial Characterization Serine Protease Inhibitors from Triticum aestivum cv' Witwol
http://hdl.handle.net/11394/10219
Isolation and Partial Characterization Serine Protease Inhibitors from Triticum aestivum cv' Witwol
Morse, Monique
Plant diseases and plant pests are major constraints to plant growth and development, resulting in severe crop losses annually. Plant pathogens can be a variety of things, living and non-living. Non-living pathogens exist as physical conditions that plants are exposed to- climatic conditions can cause damage to plants and there are various agricultural practices that can also be harmful to the plant. Living pathogens are called parasitic or infectious diseases and are extremely contagious and can spread from plant to plant very quickly. Insects, nematodes, mites and higher animals can be considered as pathogens, as are slime mold, bacteria, fungi and parasitic higher plants. Viruses and viroids are also considered pathogens (URL ). Fungal diseases, in particular, severely limit the production of major crops, as do insect crop pests. Effective control of pathogens has led to widespread use of chemical fungicides and insecticides, but with potentially deleterious environmental and human health consequences associated with this practice, strategies to utilize natural host plant resistance mechanisms for disease control are being pursued (Yun e/ a1.,1997). The agrochemical industry has been actively looking for less damaging ways to control insect pests, and has introduced a number of more environmentally friendly pesticides. In addition, alternative strategies for
pathogen and pest control have been pursued, such as biological control, and the use of plant varieties with inherent resistance
>Magister Scientiae - MSc
2001-01-01T00:00:00ZGenetic variation of rana fuscigula in Southern Africa
http://hdl.handle.net/11394/10144
Genetic variation of rana fuscigula in Southern Africa
Arieff, Zainunisha
Naturalists have long been engaged in describing and explaining diversity in the biological world. The discovery of the molecular basis of inheritance has led to rapid increase in the use of biological macromolecules in these investigations. Scientists now routinely investigate the DNA of a range of organisms. The elationships between taxa and the phylogeny of groups is determined by examining the differences and similarities between them. These differences are then appropriately analyzed. lt is important to understand the natural variation within a group, before the differences between groups can be established. This study aims to determine the molecular differences between individuals at the extreme edges of the distribution of a species. This will serve as a molecular baseline, from which other studies can proceed. The experimental species is the trog Rana fuscigula, which has a range restricted to southern Namibia and South Africa. lt was thus possible to collect material from the edge of the distribution assuming that maximum genetic
difference would be found between individuals at the edge of the range
>Magister Scientiae - MSc
1994-01-01T00:00:00Z"Genetic variation between two subspecies of reedfrogs in the genus Hyperolius (Anura: Hyperoliidae)"
http://hdl.handle.net/11394/10141
"Genetic variation between two subspecies of reedfrogs in the genus Hyperolius (Anura: Hyperoliidae)"
Hess, Anthony Jacobus
H. m. broadleyi and H. m. verrucosus are not only different in terms of colour pattern, but distinct genetic differences were detected in restriction site maps of their ribosomal DNA. A sequence divergence value of 13,8% was found between the subspecies. This value exceeds the range recorded between separate species of the genus Rana, ie. 2,2 % between Rana pustulosa and Rana tarahumarae, and 10, 1 % between Rana pustulosa and Rana pipiens. The value of 13,8% between the subspecies is also in the same range as that found between was detected between samples from three different localities within the distribution range of H. m. verrucosus. The genetic data associated with the different colour patterns, suggests that H. m. broadleyi and H. m. verrucosus can be regarded as distinct species. However, a similar study should be performed to examine the genetic status of the subspecies forming the gradient along the east coast of southern Africa. Although the effect of concerted evolution (as discussed in Chapter 2) allows for small sample sizes it would be useful to examine a large number of individuals especially from the overlap zones to determine the extent of genetic heterozygosity and to determine if similar genetic differences (found between H. m. broadleyi and H. m. verrucosus) exist between the rest of the subspecies. The current study has shown that genetic evaluation of all the southern African H. marmoratus subspecies could have a positive impact on the taxonomy of this group of frogs which is still unresolved. This study has identified at least two species within the H. marmoratus complex and it is possible that more species exist within the group. Because of morphological homogeneity it will be difficult to use morphological characters, but more than one molecular technique can be utilized to verify results obtained with one technique.
>Magister Scientiae - MSc
1993-01-01T00:00:00Z