181 research outputs found

    Genetic analysis among selected vernonia lines through seed oil content, fatty acids and RAPD DNA markers

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    Vernonia (Vernonia galamensis) is a new potential industrial oilseed crop. The seeds of this crop contain unusual naturally epoxidised fatty acids which are used in the production of various industrial products. The objective of this study was to evaluate and select vernonia lines in Limpopo province through seed oil content, fatty acid content and RAPD DNA markers. Significant differences were observed for the content of seed oil (22.4 - 29.05%), vernolic acid (73.09 - 76.83%), linoleic acid (13.02 - 14.05%), oleic acid (3.77 - 5.28%), palmitic acid (2.48 - 2.98%) and stearic acid (2.26 - 2.75%). Among the 13 RAPD DNA primers screened, primer OPA10 amplified DNA samples and resulted in 4 distinct groupings among tested lines. Four promising lines were selected; Vge-16, Vge-20, Vge-27 and Vge-32 using seed oil content, fatty acids and RAPD markers. The lines will be used for strategic breeding of vernonia as an alternative industrial oil crop in Limpopo province of South Africa or other similar environments

    Production, purification and characterization of celullase-free xylanase from Aspergillus terreus UL 4209

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    Aspergillus terreus, UL 4209 strain, isolated from the soil in South Africa was used to produce an extracellular cellulase-free xylanase in shake flask cultures containing oat spelt and/or birchwoodxylans. Maximum xylanase activity (35 U/ml) was observed after 96 h at 35ÂșC and pH 6 in 1% oat spelt xylan. The xylanase was purified to homogeneity by gel filtration on Sephacryl S-200. This enzyme wasfound to be a single subunit protein of 22 kDa showing optimal activity at 35ÂșC and pH 6. The enzyme retained 95% activity at 35 - 40ÂșC after 4 h incubation at pH 6 and at 50ÂșC the half-life was 5.8 h. Theapparent Km and Vmax values were 3.57 mg/ml and 55.5 mol/min per mg protein, respectively. MALDITOF and LC mass spectroscopy gave 8 peptide ions whose sequence alignments showed that thexylanase produced by this strain has homology with those of other Aspergillus strains such as A. terreus and A. versicolor. These observations showed that our strain produced a low molecular weight,acidophilic, and thermostable xylanase that may be considered for processes operated at moderate temperatures and pH such as preparation of baked cereal food, clarification of fruit juices andsaccharification of agro-residues

    Field performance of spider plant (Cleome gynandra l) under different agronomic practices

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    Field experiments were carried out at Kaguvi Vocational Training Centre located in theMidlands province of Zimbabwe, to determine the effect of planting date and fertilizertypes in enhancing the productivity of spider plant, an indigenous leafy vegetable. Theexperimental design was a split- plot arranged in a randomized complete block design(RCBD) with three blocks. The planting date was the main plot with three levels(15/10/12, 30/01/13 and 15/02/13) and the fertilizer treatments as the subplots withseven levels including a control (no fertilizer applied), 20 t/ha cattle manure, 30 t/hacattle manure, 5 t/ha poultry manure, 10 t/ha poultry manure, 300 kg/ha Compound D +100 kg/ha ammonium nitrate and 300 kg/ha Compound D + 150 kg/ha ammoniumnitrate). Growth parameters, vitamin A and C, crude protein, iron content, fresh and dryyield were significantly (p<0.05) increased by use of organic and inorganic fertilizersacross all planting dates compared to the control where no fertilizers were added. TheOctober 2012 planting date, combined with high rates of organic and inorganicfertilizers had the best response with regards to the variables measured, including theduration of the harvest period which was nine weeks, compared to the January andFebruary planting dates where harvesting was for six weeks. The inorganic fertilizersprovided readily available nutrients for uptake by the plants while the long productionperiod for the October 2012 planting date enabled the organic manures (cattle andpoultry manure) adequate time to release the nutrients for uptake, compared to theJanuary 2013 and February 2013 planting dates. It can be concluded that there is meritin staggering the planting dates while using organic and inorganic fertilizers as thepractice results in an extended harvest period. High rates of both inorganic and organicfertilizers are recommended for the different planting dates as follows; 30 t/ha cattlemanure, 10 t/ha poultry manure, 300 kg/ha Compound D + 100 kg/ha ammoniumnitrate and 300 kg/ha Compound D + 150 kg/ha ammonium nitrate.Key words: Indigenous vegetable, spider plant, planting dates, fertilizers, nutrient

    Comparative Cost of Early Infant Male Circumcision by Nurse-Midwives and Doctors in Zimbabwe

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    BACKGROUND: The 14 countries that are scaling up voluntary male medical circumcision (VMMC) for HIV prevention are also considering early infant male circumcision (EIMC) to ensure longer-term reductions in HIV incidence. The cost of implementing EIMC is an important factor in scale-up decisions. We conducted a comparative cost analysis of EIMC performed by nurse-midwives and doctors using the AccuCirc device in Zimbabwe. METHODS: Between August 2013 and July 2014, nurse-midwives performed EIMC on 500 male infants using AccuCirc in a field trial. We analyzed the overall unit cost and identified key cost drivers of EIMC performed by nurse-midwives and compared these with costing data previously collected during a randomized noninferiority comparison trial of 2 devices (AccuCirc and the Mogen clamp) in which doctors performed EIMC. We assessed direct costs (consumable and nonconsumable supplies, device, personnel, associated staff training, and waste management costs) and indirect costs (capital and support personnel costs). We performed one-way sensitivity analyses to assess cost changes when we varied key component costs. RESULTS: The unit costs of EIMC performed by nurse-midwives and doctors in vertical programs were US38.87andUS38.87 and US49.77, respectively. Key cost drivers of EIMC were consumable supplies, personnel costs, and the device price. In this cost analysis, major cost drivers that explained the differences between EIMC performed by nurse-midwives and doctors were personnel and training costs, both of which were lower for nurse-midwives. CONCLUSIONS: EIMC unit costs were lower when performed by nurse-midwives compared with doctors. To minimize costs, countries planning to scale up EIMC should consider using nurse-midwives, who are in greater supply than doctors and are the main providers at the primary health care level, where most infants are born

    Free Radical Scavenging Activity: Antiproliferative and Proteomics Analyses of the Differential Expression of Apoptotic Proteins in MCF-7 Cells Treated with Acetone Leaf Extract of Diospyros lycioides

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    Breast cancer is the most common cancer in South Africa. The acetone leaf extract of Diospyros lycioides was evaluated qualitatively and quantitatively for its antioxidant potential using DPPH assay and nitric oxide radical scavenging effect, while the viability of MCF-7 cells was evaluated using the MTT. MCF-7 treated cells were stained with Hoechst 335258 dye and annexin-V-FITC to be evaluated for apoptotic effect of the extract, while mRNA expression levels of apoptotic genes were assessed by quantitative real-time PCR and deferential protein expression levels using 2D gel electrophoresis and mass spectrometry. Results revealed presence of antioxidant constituents in the extract. Extract was shown to be cytotoxic in a concentration- and time-dependent manner. Cytotoxicity was demonstrated to be due to apoptosis, with 70% of the extract-treated cells being annexin-V-positive/PI negative at 48 hours. The extract was also shown to upregulate the expression of p53 gene with concomitant downregulation of the Bcl-2 antiapoptotic gene while differentially expressed proteins were identified as enolase, pyruvate kinase, and glyceraldehyde-3-phosphate. The extract in this study was shown to induce apoptosis at an early stage which makes it an ideal source that can be explored for compounds that may be used in the treatment and management of cancer

    Contamination of the environment by pathogenic bacteria in a livestock farm in Limpopo Province, South Africa

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    The aim of this study was to investigate the occurrence and diversity of pathogenic bacteria in the environment at a livestock farm in Limpopo Province. Environmental samples were collected from three sampling locations: cattle camp (CC), sheep camp (SHC), and goat camp (GC). Samples were processed and analysed for total bacterial counts in the Biotechnology Laboratory, University of Limpopo, South Africa. Identifications were done with Matrix Assisted Laser Disorption Ionisation Time of Flight Mass Spectometry (MALDI-TOF MS) using the simplified on plate technique. The colony forming unit formula per gram of environmental sample (CFU/g) was used to determine total bacterial counts. High counts were observed in CC and low counts in SHC for both soil and faecal samples. Bacillus species were the most dominant across the sampling locations for soil samples. Bacillus cereus occurred in 36 samples (33%), however, the frequency of isolation dominated in the CC with (44.4%), GC (22.2%) and SHC (13%). Staphylococcus aureus had the least frequency (2.2%) followed by Listeria monocytogenes (4.4%). In faecal samples, the occurrence and level of contamination with bacterial species varied across sampling locations with Escherichia coli dominating in the CC with 20% frequency, and abscent from SHC and GC.http://www.aloki.huam2020Veterinary Tropical Disease

    Antiretroviral Therapy outcomes among adolescents and youth in rural Zimbabwe

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    Around 2 million adolescents and 3 million youth are estimated to be living with HIV worldwide. Antiretroviral outcomes for this group appear to be worse compared to adults. We report antiretroviral therapy outcomes from a rural setting in Zimbabwe among patients aged 10-30 years who were initiated on ART between 2005 and 2008. The cohort was stratified into four age groups: 10-15 (young adolescents) 15.1-19 years (adolescents), 19.1-24 years (young adults) and 24.1-29.9 years (older adults). Survival analysis was used to estimate rates of deaths and loss to follow-up stratified by age group. Endpoints were time from ART initiation to death or loss to follow-up. Follow-up of patients on continuous therapy was censored at date of transfer, or study end (31 December 2008). Sex-adjusted Cox proportional hazards models were used to estimate hazard ratios for different age groups. 898 patients were included in the analysis; median duration on ART was 468 days. The risk of death were highest in adults compared to young adolescents (aHR 2.25, 95%CI 1.17-4.35). Young adults and adolescents had a 2-3 times higher risk of loss to follow-up compared to young adolescents. When estimating the risk of attrition combining loss to follow-up and death, young adults had the highest risk (aHR 2.70, 95%CI 1.62-4.52). This study highlights the need for adapted adherence support and service delivery models for both adolescents and young adults

    Dynamics of FitzHugh-Nagumo excitable systems with delayed coupling

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    Small lattices of NN nearest neighbor coupled excitable FitzHugh-Nagumo systems, with time-delayed coupling are studied, and compared with systems of FitzHugh-Nagumo oscillators with the same delayed coupling. Bifurcations of equilibria in N=2 case are studied analytically, and it is then numerically confirmed that the same bifurcations are relevant for the dynamics in the case N>2N>2. Bifurcations found include inverse and direct Hopf and fold limit cycle bifurcations. Typical dynamics for different small time-lags and coupling intensities could be excitable with a single globally stable equilibrium, asymptotic oscillatory with symmetric limit cycle, bi-stable with stable equilibrium and a symmetric limit cycle, and again coherent oscillatory but non-symmetric and phase-shifted. For an intermediate range of time-lags inverse sub-critical Hopf and fold limit cycle bifurcations lead to the phenomenon of oscillator death. The phenomenon does not occur in the case of FitzHugh-Nagumo oscillators with the same type of coupling.Comment: accepted by Phys.Rev.

    Capital Account Policies, IMF Programs and Growth in Developing Regions

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    This paper develops an adaptive learning model under uncertainty that examines evolution of capital account polices over time and across developing regions. In the framework, countries' past experiences and IMF programs influence policymakers' beliefs about the impact of capital account liberalization on growth, under the 'Mundell's trilemma constraint. The model, calibrated to data for Africa, Latin America and developing Asia, reflects relatively well capital account policies adopted in 1980-2010. It shows that even more developed countries with liberalized capital accounts may revert to controls under large output shocks. The outcomes of capital account switches are better and closer to policymakers' expectations in countries with the IMF programs, underscoring the role of complementarity of policies
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