Browsing by Author "Botha, Louise"

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    Characterizing the proteomes of selected members of the Mycobacterium tuberculosis complex
    (Stellenbosch : Stellenbosch University, 2014-04) Botha, Louise; Warren, R. M.; Gey van Pittius, N. C.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences, Molecular Biology and Human Genetics.
    ENGLISH ABSTRACT: Mycobacterium tuberculosis is a pathogenic organism that infects a third of the world’s population and causes approximately 2 million deaths per year. This pathogen is a member of the Mycobacterium tuberculosis complex (MTBC) which constitutes eleven members that share 99.9% similarity at nucleotide level and have near identical 16S rRNA. MTBC members cause Tuberculosis in a variety of host species. M. bovis and M. caprae form part of the animal-adapted MTBC members that cause disease in a variety of animal hosts (primarily bovidae) and goats, respectively. Extensive genetic analyses have been done to try and explain virulence, phenotype and host-preferences of these members with no success. Recent advances in mass spectrometry techniques enable us to analyse thousands of proteins simultaneously and explore the possible proteomic variation between these members that could contribute to the phenotypic, virulence and host-specificity characteristics of the MTBC members. In this study, we aimed to characterize the proteomes of M. bovis and M. caprae by analysing the high and or low abundance proteins, relative to M. tuberculosis H37Rv, which could possibly explain virulence mechanisms and host-specificity of these MTBC members. Whole cell lysate protein extracts were extracted from mid-log phase cultures of M. tuberculosis H37Rv (A600 = 0.7), M. bovis (A600 = 0.65) and M. caprae (A600 = 0.7). Proteins were fractionated by SDS-PAGE and in gel reduction/alkylation and trypsin digests were done. Peptides were identified using LC-MS/MS on the Orbitrap Velos mass spectrometer and their corresponding proteins were identified by searching peptide databases. Protein functional groups were assigned according to TubercuList. To provide an integrated overview of the overall network of protein expression (rather than just limit analysis to individual proteins), pathway analysis was done on the differentially expressed proteins of M. bovis and M. caprae using PATRIC (Pathosystems Resource Integration Center) and pathways were visualized using iTUBY (Interactive Pathway Explorer database). We detected 2199, 2367 and 2350 proteins for M. tuberculosis H37Rv, M. bovis and M. caprae which correlate to 60% of the proposed M. tuberculosis proteins being expressed during log-phase. Considering similarities between genomes, it was no surprise that the functional distribution of the detected proteins extracted was similar. Metabolic pathways affected by the proteins which were in higher abundance in M. bovis and M. caprae included amino acid and lipid metabolism, oxidative phosphorylation and xenobiotic degradation. The over-abundant proteins in M. bovis and M. caprae were also involved in ribosomal proteins and carbohydrate metabolism, respectively. Lower abundance proteins in these species were found in lipid and pyrimidine metabolism. These affected pathways can be associated with the ability of M. bovis and M. caprae to adapt to their environment more readily which helps them to survive inside the hosts and cause severe pathogenesis. In this study the proteomes of M. tuberculosis H37Rv, M. bovis and M. caprae were characterized and the variation between detected proteins and protein abundances explored in order to describe differences between these closely related strains. Future research on animaladapted Mycobacterial species will address knowledge gaps that are needed to prevent transmission and spread of the disease. Understanding the mechanisms of virulence and pathogenicity could lead to development of efficient vaccines and diagnostic tests for a variety of animal hosts.
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    Experimental Mycobacterium bovis infection in three white rhinoceroses (Ceratotherium simum) : Susceptibility, clinical and anatomical pathology
    (Public Library of Science, 2017) Michel, Anita L.; Lane, Emily P.; De Klerk-Lorist, Lin-Mari; Hofmeyr, Markus; Van Der Heijden, Elisabeth M. D. L.; Botha, Louise; Van Helden, Paul; Miller, Michele Ann; Buss, Peter E.
    Tuberculosis caused by Mycobacterium bovis is endemic in the African buffalo (Syncerus caffer) population in the Kruger National Park and other conservation areas in South Africa. The disease has been diagnosed in a total of 21 free ranging or semi-free ranging wildlife species in the country with highly variable presentations in terms of clinical signs as well as severity and distribution of tuberculous lesions. Most species are spillover or dead-end hosts without significant role in the epidemiology of the disease. White rhinoceroses (Ceratotherium simum) are translocated from the Kruger National Park in substantial numbers every year and a clear understanding of their risk to manifest overt tuberculosis disease and to serve as source of infection to other species is required. We report the findings of experimental infection of three white rhinoceroses with a moderately low dose of a virulent field isolate of Mycobacterium bovis. None of the animals developed clinical signs or disseminated disease. The susceptibility of the white rhinoceros to bovine tuberculosis was confirmed by successful experimental infection based on the ante mortem isolation of M. bovis from the respiratory tract of one rhinoceros, the presence of acid-fast organisms and necrotizing granulomatous lesions in the tracheobronchial lymph nodes and the detection of M. bovis genetic material by PCR in the lungs of two animals.
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    In-service teachers' perspectives of pre-service teachers' knowledge domains in science
    (Education Association of South Africa, 2011) Botha, Louise; Reddy, Chris
    The concept of pedagogical content knowledge is integral to teaching as a profession and is often considered to be an important aspect of a teacher's lived experience. Pedagogical content knowledge (PCK) is described as a transformation of teacher knowledge from a variety of domains of knowledge, which includes subject matter knowledge, pedagogical knowledge, and knowledge about content. This exploratory study reports on in-service natural science teachers' inferences regarding preservice teachers' performance in natural science teaching, as observed during a practice teaching period. Perspectives of in-service teachers of the different knowledge domains of pre-service teachers during their final year were investigated. Semi-structured interviews, incorporating a specific set of open-ended questions, were conducted with in-service teachers following a practice teaching period of four weeks. The findings indicate that the in-service teachers rated the pre-service teachers positively in some knowledge domains but less positively in other knowledge domains. This has prompted some rethinking on the structure and presentation of the curriculum, in our undergraduate teacher education programme, to include and accommodate approaches that would enable better uptake of various knowledge domains and improve PCK development. © 2011 EASA.
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    Paratuberculosis in a domestic dog in South Africa
    (AOSIS Publishing, 2017) Miller, Michele Ann; Davey, Sewellyn C.; Van Helden, Lesley S.; Kettner, Frank; Weltan, Sandy M.; Last, Rick; Grewar, John D.; Botha, Louise; Van Helden, Paul D.
    This case report shows that Mycobacterium avium subsp. paratuberculosis (MAP) infection can cause clinical disease in domestic dogs, and should be considered as a differential diagnosis for gastrointestinal inflammatory conditions. A male dachshund presented with lethargy and pain. Enlarged mesenteric lymph nodes were found on abdominal ultrasound examination. Cytological examination of lymph node aspirates was consistent with granulomatous inflammation, which was culture-confirmed as MAP. Although we were unable to confirm the source of infection, the dog’s history included exposure to sheep in the Western Cape.
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    Species diversity of non-tuberculous mycobacteria isolated from humans, livestock and wildlife in the Serengeti ecosystem, Tanzania
    (BioMed Central, 2014-11-18) Katale, Bugwesa Z.; Mbugi, Erasto V.; Botha, Louise; Keyyu, Julius D.; Kendall, Sharon; Dockrell, Hazel M.; Michel, Anita L.; Kazwala, Rudovick R.; Rweyemamu, Mark M.; Van Helden, Paul; Matee, Mecky I.
    Background: Non-tuberculous mycobacteria (NTM), which are ubiquitous micro-organisms occurring in humans, animals and the environment, sometimes receive public health and veterinary attention as opportunistic disease-causing agents. In Tanzania, there is limited information regarding the diversity of NTM species, particularly at the human-livestock-wildlife interface such as the Serengeti ecosystem, where potential for cross species infection or transmission may exist. Methods: Mycobacterial DNA was extracted from cultured isolates obtained from sputum samples of 472 suspect TB patients and 606 tissues from wildlife species and indigenous cattle. Multiplex PCR was used to differentiate NTM from Mycobacterium tuberculosis complex (MTBC) members. NTM were further identified to species level by nucleotide sequencing of the 16S rRNA gene. Results: A total of fifty five (55) NTM isolates representing 16 mycobacterial species and 5 isolates belonging to the MTBC were detected. Overall, Mycobacterium intracellulare which was isolated from human, cattle and wildlife, was the most frequently isolated species (20 isolates, 36.4%) followed by M. lentiflavum (11 isolates, 20%), M. fortuitum (4 isolates, 7.3%) and M. chelonae-abscessus group (3 isolates, 5.5%). In terms of hosts, 36 isolates were from cattle and 12 from humans, the balance being found in various wildlife species. Conclusion: This study reveals a diversity of NTM species in the Serengeti ecosystem, some of which have potential for causing disease in animals and humans. The isolation of NTM from tuberculosis-like lesions in the absence of MTBC calls for further research to elucidate their actual role in causing disease. We are also suggesting a one health approach in identifying risk factors for and possible transmission mechanisms of the NTM in the agro-pastoral communities in the Serengeti ecosystem.