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Antibacterial activities of crude secondary metabolite extracts from Pantoea species obtained from the stem of Solanum mauritianum and their effects on two cancer cell lines

- Uche-Okereafor, Nkemdinma Chinezurum, Sebola, Tendani, Tapfuma, Kudzanai, Mekuto, Lukhanyo, Green, Ezekiel, Mavumengwana, Vuyo

Antibacterial and anticancer activity and untargeted secondary metabolite profiling of crude bacterial endophyte extracts from cinum macowanii baker leaves

- Sebola, Tendani E., Uche-Okereafor, Nkemdinma Chinezurum, Mekuto, Lukhanyo, Makatini, Maya Mellisa, Green, Ezekiel, Mavumengwana, Vuyo

Anticancer activity and metabolite profiling data of Penicillium janthinellum KTMT5

- Tapfuma, Kudzanai Ian, Sebola, Tendani Edith, Uche-Okereafor, Nkemdinma Chinezurum, Koopman, Jody, Hussan, Raeesa, Makatini, Maya Mellisa, Mekuto, Lukhanyo, Mavumengwana, Vuyo

Cytotoxic activity of crude extracts from Datura stramonium’s fungal endophytes against A549 lung carcinoma and UMG87 glioblastoma cell lines and LC-QTOF-MS/MS based metabolite profiling

- Tapfuma, Kudzanai Ian, Uche-Okereafor, Nkemdinma Chinezurum, Sebola, Tendani Edith, Hussan, Raeesa, Mekuto, Lukhanyo, Makatini, Maya Mellisa, Green, Ezekiel, Mavumengwana, Vuyo

Dataset on assessment of pollution level of selected trace metals in farming area within the proximity of a gold mine dump, Ekuhurleni, South Africa

- Okereafor, Uchenna, Makhatha, Elizabeth, Mekuto, Lukhanyo, Mavumengwana, Vuyo

Evaluating antibacterial and anticancer activity of crude extracts of bacterial endophytes from Crinum macowanii Baker bulbs

- Sebola, Tendani E., Uche‐Okereafor, Nkemdinma C., Tapfuma, Kudzanai I., Mekuto, Lukhanyo, Green, Ezekiel, Mavumengwana, Vuyo

  • Authors: Sebola, Tendani E. , Uche‐Okereafor, Nkemdinma C. , Tapfuma, Kudzanai I. , Mekuto, Lukhanyo , Green, Ezekiel , Mavumengwana, Vuyo
  • Date: 2019
  • Subjects: Antibacterial activity , Anticancer activity , Crinum macowanii bulbs
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/399949 , uj:33357 , Citation: Sebola, T.E. et al. 2019. Evaluating antibacterial and anticancer activity of crude extracts of bacterial endophytes from Crinum macowanii Baker bulbs. , DOI: 10.1002/mbo3.914
  • Description: Abstract: The results from this study revealed that crude extracts isolated from bacterial endophytes obtained from Crinum macowanii bulbs showed activity against both Grampositive and Gram‐negative pathogenic bacteria, while Acinetobacter guillouiae crude extracts displayed anticancer activity. This study aimed to isolate and characterize bacterial endophytes and their crude extracts from C. macowanii bulbs. Endophytes were isolated using validated surface sterilization techniques, followed by phenotypic and genotypic profiles of the isolates. Crude extracts were extracted from the endophytes using ethyl acetate, while methanol:dichloromethane (1:1) was used to obtain crude extracts from the bulbs. Antibacterial activity of crude extract from each endophyte was investigated against selected pathogenic strains using the broth microdilution method, and anticancer activity against U87MG glioblastoma and A549 lung carcinoma cells was determined by the MTS (3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐ carboxymethoxy‐phenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium) assay. Acinetobacter guillouiae, Pseudomonas moraviensis, Pseudomonas sp., Rahnella aquatilis, Bacillus cereus, Novosphingobium sp., Raoultella ornithinolytica, and Burkholderia tropica were successfully isolated. The crude extracts from the majority of endophytes showed antibacterial activity, ranging from 0.125 to >16.00 mg/ml against Gram‐negative and Gram‐positive pathogenic bacteria. Acinetobacter guillouiae extracts showed a high bioactive potential against U87MG glioblastoma cell lines by reducing their growth by 50% at concentrations of 12.5, 6.25, and 3.13 μg/ml. Crude extracts isolated from C. macowanii bulbs showed potential for possible drug lead against common pathogenic bacteria.
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Evaluation of trace elemental levels as pollution indicators in an abandoned gold mine dump in Ekurhuleni Area, South Africa

- Okereafor, Godwin, Makhatha, Mamookho, Mekuto, Lukhanyo, Mavumengwana, Vuyo

  • Authors: Okereafor, Godwin , Makhatha, Mamookho , Mekuto, Lukhanyo , Mavumengwana, Vuyo
  • Date: 2019
  • Subjects: Mine tailings , Trace metal , Pollution
  • Language: English
  • Type: Book Chapter
  • Identifier: http://hdl.handle.net/10210/406531 , uj:34183 , Citation: Okereafor, G. et al. 2019 : Evaluation of trace elemental levels as pollution indicators in an abandoned gold mine dump in Ekurhuleni Area, South Africa.
  • Description: Abstract : In the Blesbokspruit area of Ekuhurleni, South Africa, previous gold mining activities resulted in many tailings dump sites. 20 representative soil samples were used in describing the distribution of metals. The soils were very strongly acidic ranging from 3.86 to 4.34 with a low cation exchange capacity (CEC). Based on X-ray fluorescence (XRF) analysis, elemental composition of the soils revealed average values of major elements such as Na2O (0.18%), MgO (0.63%), Al2O3 (6.51%), SiO2 (81.83%), P2O5 (0.04%), SO3 (3.40%), K2O (1.98%), CaO (0.45%), TiO2 (0.51%), Cr2O3 (0.17%), MnO (0.04%), Fe2O3 (3.59%), NiO (0.04%), As2O3 (0.02%), with Rb2O and SrO falling below 0.01%. Trace metals (TM) contamination levels in the soils were evaluated using various pollution indices which revealed that over 60% of the soils were between the high degree and the ultra-high degree of contamination classes. The concentration of various trace metals varies from 860.3–862.6 mg/kg for Cr; 324.9–328.4 mg/kg for Al; 200.9– 203.4 mg/kg for As; 130.1–136.2 mg/kg for Fe; 121.9–125.8 mg/kg for Pb; 27.3–30.2 mg/kg for Co; 23.8–26.8 mg/kg for Ni; 7.2–9.2 mg/kg for Ti; 7.1–9.2 mg/kg for Cd; 4.0–5.6 mg/kg for Zn and 0.1–0.6 mg/kg for Cu.
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Gold mine tailings : a potential source of silica sand for glass making

- Okereafor, Uchenna, Makhatha, Mamookho, Mekuto, Lukhanyo, Mavumengwana, Vuyo

  • Authors: Okereafor, Uchenna , Makhatha, Mamookho , Mekuto, Lukhanyo , Mavumengwana, Vuyo
  • Date: 2020
  • Subjects: Silica sand , Beneficiation , Characterization
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/434089 , uj:37559 , Okereafor, U. et al. 2020: Gold mine tailings : a potential source of silica sand for glass making.
  • Description: Abstract: , Mining of minerals such as gold, copper, and platinum has been one of several activities sustaining the economy of South Africa. However, the mining sector has contributed significantly to environmental contamination through the improper disposal of mine tailings which covers vast areas of land. Therefore, this study utilised a vitrification process to manufacture glass from gold mine tailings. X-ray fluorescence was used to determine the chemical composition of the tailings while X-ray diffraction was adopted for the mineralogy. The tailings were of granitic composition enriched in potentially toxic elements such as copper, cadmium, zinc, lead, arsenic, and chromium. A representative sample of gold mine wastes of sandy grain size was used in making the glass. Based on composition, the glass was formulated by adding an average 10.0 mass% of CaCO3 and 5.0mass%ofNa2CO3 to35.0mass%ofSiO2,whichresultedintheproductionofagreen-colouredglass.
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The LC-QTOF-MS/MS analysis data of detected metabolites from the crude extract of Datura stramonium leaves

- Tapfuma, Kudzanai Ian, Mekuto, Lukhanyo, Makatini, Maya Mellisa, Mavumengwana, Vuyo

Toxic metal implications on agricultural soils, plants, animals, aquatic life and human health

- Okereafor, Uchenna, Makhatha, Mamookho, Mekuto, Lukhanyo, Uche-Okereafor, Nkemdinma Chinezurum, Sebola, Tendani, Mavumengwana, Vuyo

  • Authors: Okereafor, Uchenna , Makhatha, Mamookho , Mekuto, Lukhanyo , Uche-Okereafor, Nkemdinma Chinezurum , Sebola, Tendani , Mavumengwana, Vuyo
  • Date: 2020
  • Subjects: Toxic metals , Contamination , Toxicity
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/434097 , uj:37560 , Okereafor, U. et al. 2020: Toxic metal implications on agricultural soils, plants, animals, aquatic life and human health.
  • Description: Abstract: , Theproblemofenvironmentalpollutionisaglobalconcernasitaffectstheentireecosystem. There is a cyclic revolution of pollutants from industrial waste or anthropogenic sources into the environment, farmlands, plants, livestock and subsequently humans through the food chain. Most of the toxic metal cases in Africa and other developing nations are a result of industrialization coupled with poor effluent disposal and management. Due to widespread mining activities in South Africa, pollution is a common site with devastating consequences on the health of animals and humans likewise. In recent years, talks on toxic metal pollution had taken center stage in most scientific symposiums as a serious health concern. Very high levels of toxic metals have been reported in most parts of South African soils, plants, animals and water bodies due to pollution. Toxic metals such as Zinc (Zn), Lead (Pb), Aluminium (Al), Cadmium (Cd), Nickel (Ni), Iron (Fe), Manganese (Mn) and Arsenic (As) are major mining effluents from tailings which contaminate both the surface and underground water, soil and food, thus affecting biological function, endocrine systems and growth. Environmental toxicity in livestock is traceable to pesticides, agrochemicals and toxic metals. In this review, concerted efforts were made to condense the information contained in literature regarding toxic metal pollution and its implications in soil,water,plants,animals,marine life and human health.
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