Browsing by Author "Dhlamini, Zephaniah"

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    Characterization of Fasciola gigantica isolates from cattle from South-western Zimbabwe using RAPD-PCR
    (International Organization Of Scientific Research (IOSR)., 2014) Chauke, E.; Dhlamini, Zephaniah; Mbanga, Joshua; Dube, S.
    The study sought to characterize Fasciola gigantica isolates from cattle in different localities using RAPD-PCR. Adult flukes morphologically identified as F. gigantica were collected from slaughtered infected animals during meat hygiene inspections. DNA was extracted from single flukes and subjected to RAPD-PCR analysis. In the RAPD-PCR analysis, genomic DNA isolated from the conical anterior end of the worms was amplified by the polymerase chain reaction using 10 random oligonucleotide primers. Depending upon the Fasciola gigantica isolate-primer combination, 1-13 DNA fragments in the range of 75-2000bp were amplified. It was observed that all the 10 primers directing amplification of DNA were of potential interest in the generation of polymorphic DNA. The percentage polymorphic loci ranged from 33.33-100%. Polymorphic bands were scored and used to calculate Nei’s 1978 genetic distance. The genetic distance values ranged between 0.0690 (isolate 5 and 6 from Gwanda and 0.6109 (isolate 6 from Gwanda and isolate 14 from Matopo). The mean Nei’s gene diversity was 0.2839. The study showed the variability of Fasciola gigantica isolates from the same host, using RAPD markers could be applied as a low cost way of identification
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    Diagnosis of Multi-drug Resistant Tuberculosis Mutations Using Hain Line Probe Assay and GeneXpert: A Study Done in Zimbabwe
    (SCIENCEDOMAIN international, 2015) Dube-Mandishora, Rachea, S.; Dhlamini, Zephaniah; Mutetwa, Reggie; Duri, Kerina; Mason, Peter; Stray-Pedersen, Babill
    Background and Aims: Tuberculosis (TB) is a global public health problem and one of the leading causes of death. Worldwide, 31% of all estimated new TB cases are from Africa. Zimbabwe is one of the 22 high TB burden countries. Multi-drug resistant TB (MDR-TB) poses challenges in TB control, hence the need for rapid laboratory diagnosis of MDR-TB for optimal treatment and reducing spread. The study aim was to investigate genetic mutations associated with MDR-TB isolates from various Harare clinics using the GeneXpert MTB/RIF® by Cepheid and Genotype MTBDRplus, to improve the diagnosis and management of MDR-TB. Methods: Samples from adults aged 16 years and older, recruited from several polyclinics in the southern suburbs of Harare were used for our study. All laboratory tests prior to this study had been carried out at Biomedical research and training institute’s level three bio-safety TB laboratory from January 2008-August 2012. Ethical approval was sought from BRTI Institutional review board. A total of 69 (37 MDR-TB and 32 non MDR-TB) archived isolates processed on Genotype MTBDRplus (Hains) and corresponding 39 sputum were processed on the GeneXpert. Mutations on rpoB, katG and inhA genes were observed. The gold standard was culture. Diagnostic accuracy of both methods and their level of agreement were calculated. Results: Of the 37/69 isolates screened by culture for MDR-TB, 88.4% were confirmed by MTBDR® plus line probe assay (Hains). Within the 39 isolates tested using the Xpert MTB/RIF (GeneXpert) assay 12 were true MDR-TB. Over 8 single nucleotide polymorphisms were observed on the three genes conferring Rifampicin and Isoniazide drug resistance. The Hains and GeneXpert had an almost perfect agreement with a kappa value of 0.82. Conclusion: Genetic markers can be used in the diagnosis of MDR-TB, to complement phenotypic methods such as culture. Using the commercial methods, Hains and GeneXpert, 88.4- 94.2% of drug resistance maybe detected. Furthermore, we recommend sequencing so as to identify novel mutations and to design a kit that is custom made for the population.
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    The Efficacy of Alkaline Steeping in Extracting Proanthocyanidins and its effects on Malt quality in some Sorghum varieties
    (Society of Education, 2013-12) Dhlamini, Zephaniah; Banda, L.; Makoni, C.
    Sorghum malt is an important raw material in opaque beer brewing. Use of high tannin sorghum varieties reduces malt quality due to binding of tannins to proteins. Tannins are usually leached from sorghum grain using formalin during the steeping stage of malting. However, formalin has been shown to have potentially harmful health effects thus driving the need to find alternative methods of tannin removal. In this study, the effectiveness of alkalis (calcium and sodium hydroxides) was assessed. The amount of tannins in red (NS5511) and brown (SMILE) malting sorghum varieties were determined by the butanol-HCl assay and compared to other food varieties. The NS5511 and SMILE were steeped in 0.02M and 0.04M concentrations of each of Ca(OH)2, NaOH and formalin for 6hrs, subjected to germination conditions (26°C for 115hours) and kilned off at 60°C for 50hours. The germination rate, as measured by the chit count was determined and the alkali treated samples had the highest germination rates compared to formalin. Furthermore, the alkali treated samples had highest diastatic units. The amount of residual tannins was determined, and formalin treatment leached slightly more tannins than the alkalis. We conclude that alkalis can replace formalin since they are almost equally effective and have less serious health effects.
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    Metagenome Sequencing of the Greater Kudu ( Tragelaphus strepsiceros ) Rumen Microbiome.
    (Genome Journals., 2015-08) Dube, Anita Nompumelelo; Dhlamini, Zephaniah
    Ruminant herbivores utilize a symbiotic relationship with microorganisms in their rumen to exploit fibrous foods for nutrition. We report the metagenome sequences of the greater kudu (Tragelaphus strepsiceros) rumen digesta, revealing a diverse community of microbes and some novel hydrolytic enzymes.
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    Molecular analysis of selected paramphistome isolates from cattle in southern Africa.
    (Journal of Helminthology, 2015-10) Dhlamini, Zephaniah
    Paramphistomes are parasites of domestic and wild ruminants, the effects of which in animal health remain underestimated. Very few studies in Africa have been done using molecular techniques to resolve situations associated with taxonomical groupings and epidemiology of these parasites. In this study, the genetic variability of nine representative paramphistome isolates collected from southern African countries, namely Botswana, South Africa, Zambia and Zimbabwe, was assessed using both morphological and internal transcribed spacer 2 (ITS2) rDNA sequence data. Morphological characterization and identification were carried out using median sagittal sections of the paramphistomes. DNA of the individual paramphistomes was isolated, the ITS2 rDNA was amplified, purified and sequenced. The sequences were submitted to GenBank, which assigned them the following accession numbers: KP639631, KP639630, KP639632, KP639633, KP639634, KP639635, KP639636, KP639637 and KP639638. These sequences were used for phylogenetic analysis using MEGA 6. Morphological characterization revealed three species of paramphistomes belonging to three different sub-families: one Stephanopharynx compactus isolate, a member of the Stephanopharyngidae sub-family; one Carmyerius dollfusi isolate, a member of the Gastrothylacidae sub-family; and seven Calicophoron microbothrium isolates belonging to the Paramphistomidae sub-family. ITS2 sequence analysis using BlastN results indicated that this is the first report of S. compactus (KP639630) and C. dollfusi (KP639636). Phylogenetic reconstruction of the paramphistome isolates revealed three separate clades representing the three species. However, the clade with all the C. microbothrium isolates was the only one that was supported by a higher bootstrap value of 92%, although there was no differentiation of the isolates according to geographical locations. The low divergence values on the ITS2 sequences of the C. microbothrium isolates indicate that ITS rDNA sequences can be used as a molecular tool to infer knowledge for resolving taxonomic groupings.
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    Molecular Characterization of Paramphistomes fromCattle from Matebeleland Region (Zimbabwe) using RandomAmplified Polymorphic DNA (RAPDs) and Amplified Ribosomal DNA Restriction Analysis (ARDRA)
    (Society of Education, 2014) Sibula, M.S.; Dhlamini, Zephaniah; Dube, S.
    Paramphistome isolates collected from local abattoirs were genetically characterised using the Random Ampl41i47fied Polymorphic DNA (RAPD) technique and Amplified Ribosomal DNA Restriction Analysis (ARDRA). These isolates were morphologically characterized using median sectioning and five putative species were identified. Of the 18 isolates that were being investigated, 16 were positively identified: three belonged to Calicophoron calicophorum, two were Calicophoron microbothrium, one was Gigantocotyle symmeri, 6 were identified as Calicophoron raja and the other 6 were identified as Calicophoron clavula. A restriction digest of the amplified ITS-2 region of all isolates was done using two restriction enzymes Hae III and Sau 3A1 and the fragments obtained did not show any detectable polymorphisms on all isolates. A total number of 110 bands were generated by RAPD-PCR and 91.82% of these were polymorphic with an average genetic distance of 0.4810+/- 0.185 that showed substantial variability among the paramphistome isolates. The RAPD-PCR technique however, gave banding patterns that on analysis were able to cluster (on the dendrogram) the isolates into their respective species groups and even aid in identifying the two isolates that were not positively identified morphologically as Calicophoron raja. A fragment of approximately 1300bp was generated from primer OPB 07 on Calicophoron microbothrium isolates which can be used as a selectable marker for this species. The findings of the present study therefore showed that the RAPD- PCR technique can be used for molecular identification of paramphistomes.
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    Mutations in rpoB and katG genes of multidrug resistant mycobacterium tuberculosis undetectable using genotyping diagnostic methods
    (African Field Epidemiology Network, 2017-06-28) Takawira, Faustinos Tatenda; Mandishora, Racheal S. D.; Dhlamini, Zephaniah; Munemo, Ellen; Stray-Pedersen, Babill
    Introduction: Tuberculosis remains the leading causes of death worldwide with frequencies of mutations in rifampicin and isoniazid resistant Mycobacterium tuberculosis isolates varying according to geographical location. There is limited information in Zimbabwe on specific antibiotic resistance gene mutation patterns in MTB and hence, increased rate of discordant results and mortality due to inappropriate antibiotic prescriptions. The rpoB and katG genes molecular markers are used for detecting rifampicin and isoniazid resistance respectively. Some mutations within these gene sequences are associated with drug resistance as they directly alter gene function. The objectives of this research was to determine the drug resistance profiles in M. tuberculosis isolates that are phenotypically resistant but not detected by the GeneXpert and MTBDRplus kit and also to detect mutations in the rpoB and katG genes which are not detected by the Hain Genotype MTBDRplus kit and GeneXpert diagnosis. Methods: PCR was used for the amplification of the rpoB and katG genes from MTB isolates collected from human clinical samples between 2008 and 2015. The genes were sequenced and compared to the wild type MTB H37Rv rpoB (accession number L27989) and kat G genes (KP46920), respectively. Sequence analysis results were compared to genotyping results obtained from molecular assays and culture results of all isolates. Results: The most frequent mutation responsible for rifampicin resistance was (25/92) S531L that was detected by using all molecular assays. Some inconsistencies were observed between phenotypic and genotypic assay results for both katG and rpoB genes in 30 strains. For these, eight codons; G507S, T508A, L511V, del513-526, P520P, L524L, R528H, R529Q and S531F were novel mutations. In addition, the I572P/F, E562Q, P564S, and Q490Y mutations were identified as novel mutations outside the rifampicin resistance determining region. In katG gene, amino acid changes to threonine, asparagine and isoleucine exhibited high degrees of polymorphism such as V473N, D311N, and L427I. The R463L (20/92) amino acid substitution was most common but was not associated with isoniazid resistance. Conclusion: These finding indicate that molecular assay kit diagnosis that is based on the rpoB and katG genes should be improved to cater for the genetic variations associated with the geographic specificity of the target genes and be able to detect most prevalent mutations in different areas.
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    Random Amplified Polymorphic DNA (RAPD) Based Assessment of Genetic Relationships among some Zimbabwean Sorghum Landraces with Different Seed Proanthocyanidin Levels.
    (academicjournals, 2014-05-07) Dhlamini, Zephaniah; Sithole-Niang, I
    Knowledge of genetic distances between genotypes is important for efficient organization and conservation of plant genetic resources for crop improvement programs. In this study genetic distances between genotype pairs (complements of Jaccard's similarity coefficient) were estimated from Random Amplified Polymorphic DNA (RAPD) data collected from 48 Zimbabwean sorghum landraces. These varieties showed variation in their seed proanthocyanidin (PAs) levels with 16 and 29 of them having detectable and non-detectable PA levels respectively. RAPDs revealed considerable genetic variation between the varieties used and 2.7 polymorphisms per primer were obtained. Ninety nine polymorphic RAPD bands were used to calculate genetic distances and the mean genetic distance between the genotypes was 0.494 (± 0.113) with a range of 0.051 to 0.761. A multidimensional scaling (MDS) plot of the distance matrix revealed two distinct clusters of cultivated and wild sorghums. No clustering of genotypes according to their seed proanthocyanidin levels was revealed by MDS analysis; also the mean genetic distances of genotypes in the low, medium and high PA categories were not different from each other and none of them was significantly different from the mean genetic distances between all the groups. The RAPD markers used in the present study could not distinguish between sorghums with different PA levels in their seeds; however, the protocol established could be useful in further analysis of this trait in near isogenic lines.
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    Sensitivity of Some Pathogen Isolates to Fungicides Commonly Used in Vegetable Greenhouses in Zimbabwe.
    (Zimbabwe Journal of Science & Technology, 2014) Mtasa, T.; Mangoma, Ngonidzashe; Dhlamini, Zephaniah
    The adoption of greenhouse technology for the production of high value vegetables is on the increase in Zimbabwe. This production system is chemical intensive in pest, disease and mineral nutrition management. This study sought to survey the prevalence of fungal diseases in greenhouse grown tomatoes, cucumber and green pepper in and around Bulawayo and to investigate the sensitivity of the isolated fungal pathogens to commonly used fungicides. Infected plant parts were collected for laboratory analyses from clearly diseased plants. Six fungal pathogens, namely Phytophthora infestans, Fusarium oxysporum f. Sp lycopersici, Peronospora, Botrytis cinerea, Leveillula taurica and Spaerotheca fuliginea, were isolated from these crops in the laboratory. These fungal isolates were evaluated for their susceptibility to the following commonly used fungicides: Copper Oxychloride, Chlorothalonil, Dithane M-45, Saaf and Didecyl Dimethyl Ammonium Chloride (DDAC – Spore Kill), using the broth macro-dilution method. The fungal isolates showed varied sensitivity to the test fungicides. All fungal isolates were completely inhibited by all the concentrations of Copper Oxychloride and Chlorothaloni used, except for Phytophthora infestans, which showed resistance at all the concentrations of these fungicides used, and Fusarium oxysporium which was resistant to 0.075 % Chlorothalonil. Both Dithane and Saaf were able to inhibit fungal growth at the recommended concentration, i.e. 0.2 %. Spore Kill (DDAC) completely inhibited all the fungal isolates at all the concentrations used. The best fungicidal activity was obtained with Spore kill, followed by Copper Oxychloride and then Chlorothalonil. Phytophthora infestans displayed resistance to all the fungicides except to Spore Kill, followed by Fusarium oxysporium. Botrytis cinerea was the most susceptible isolate to all the fungicides tested. All fungicides were effective at, or just below, their recommended concentration levels, except for Spore Kill which was effective across the board. Even though Spore Kill is a recent addition to the fungicides currently in use in greenhouses in Zimbabwe, the results of this study show that it can be adopted as a preventative fungicide in greenhouses with high levels of success.
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    A survey on entomophagy in Zimbabwe.
    (AJFAND., 2013-01) Dhlamini, Zephaniah; Dube, S.
    This study was to determine the prevalence of entomophagy in the post independence era (after 1980) in Zimbabwe given that the social status of many families has changed. A cross-sectional non probability sampling was used to determine who ate which insect and how much they ate and where they came from. The availability of each insect was determined at provinces and through key informants. Data were collected through questionnaires and physical visits to all provinces of Zimbabwe to collect empirical data. The population of those that never participated in entomophagy was less than 10% across the age groups in the sampled populations. In the order, Lepidoptera, which comprises several species the larval stages are mostly consumed in the fourth instar after degutting. The caterpillars are known locally as madora. Imbrasia belina was consumed by more than 90% of the respondents. In the order Isoptera Macrotermes sp. [ishwa] were consumed by more than 80% of the respondents. In the order Coleoptera Eulepida sp, [mandere] and Sternocera orissa [zvigakata] are also widely consumed. In the order Hemiptera only, Encosternum delegorguei [Haruwa] adult is consumed. In the order Homoptera only Loba leopardina [Nyeza nyeza] adult is consumed. In the order Hymenoptera only Carebara vidua [Tsambarafuta] adult is consumed. In the order Orthoptera Brachytrupes membranaceus [Gurwe], Locusta migratoria [mhashu] and Ruspolia differens [Nswabanda] are consumed. Records of quantities of insects harvested are here presented. Protein content of fully grown Imbrasia belina done by the Kjeldahl method was 54-58%. Matebeleland province had the highest tonnage of insects, most of which were exported to other provinces even to neighbouring countries. Manicaland harvested the least quantities of insects. Most of those who consumed insects preferred them in the dried form which were said to have improved organoleptic properties. Drying the insects prolonged their shelf life. Food security strategies for Zimbabwe should include management of harvesting and storage of these insects.