Dechlorination of 1,2– dichloroethane by Pseudomonas aeruginosa OK1 isolated from a waste dumpsite in Nigeria

As part of our attempt at isolating and stocking some indigenous microbial species, we isolated a bacterium from a waste dumpsite with appreciable dechlorination activity. 16S rDNA profiling revealed the isolate to be a strain of Pseudomonas aeruginosa and the sequence has been deposited in the NCBI nucleotide sequence database (accession number AJ550306). The bacterium utilized 0.1% (v/v) 1, 2 – dichloroethane (1, 2 – DCE) as sole source of carbon and attained peak cell density of 6.0 × 107 cfu/ml in 48 h. It also has a proportionate increase in chloride release during this period resulting in the release of 80% free Cl-. The bacterium also had dehalogenase activities against other chlorinated organics such as monochloroacetic acid, trichloroacetic acid, dichloromethane, trichloromethane and tetrachloromethane at pH 7.5 and 9.0. Optimum temperature for dehalogenase activity against 1, 2 – DCE was 35oC. Key Words: Dechlorination, 16S rDNA, bioremediation, Pseudomonas aeruginosa OK1. African Journal of Biotechnology Vol.3(10) 2004: 508-51

Developing an ionospheric map for South Africa

The development of a map of the ionosphere over South Africa is presented in this paper. The International Reference Ionosphere (IRI) model, South African Bottomside Ionospheric Model (SABIM), and measurements from ionosondes in the South African Ionosonde Network, were combined within their own limitations to develop an accurate representation of the South African ionosphere. The map is essentially in the form of a computer program that shows spatial and temporal representations of the South African ionosphere for a given set of geophysical parameters. A validation of the map is attempted using a comparison of Total Electron Content (TEC) values derived from the map, from the IRI model, and from Global Positioning System (GPS) measurements. It is foreseen that the final South African ionospheric map will be implemented as a Space Weather product of the African Space Weather Regional Warning Centre

Biochemical effects of ethylene diamine tetra-acetic acid (EDTA) on cadmium treated maize (Zea mays L.) and cowpea (Vigna unguiculata L.)

The effects of ethylenediaminetetra-acetic acid (EDTA) on germination, length of stem, area of leaf, fresh weight, level of lipid per oxidation, alkaline phosphatase, acid phosphatase, super oxide dismutase (SOD) and catalase in the roots of cadmium (Cd) treated maize (Zea mays L) and cowpea (Vigna unguiculata L) seedlings after 7 and 21 days of germination were determined in this study. The results obtained, indicate that at the end of 7 and 21 days of exposure to Cd, percentage germination of the seeds were not significantly different in both control and test soil (p>0.05). Morphological parameters (area of leaf, length of stem and fresh weight) were significantly reduced by Cd after 7 and 21 days. The supplementation of the soil sample with EDTA (0.5 mM or 1.0 mM) reversed the effect of Cd on these parameters as it significantly increased length of stems, area of leaf and plant fresh weight. There was a significant decrease in root acid phosphatase, root alkaline phosphatase, super-oxide dismutase (SOD) and catalase activity in both plant species. Both used doses of EDTA to ameliorate the above biochemical parameters. Increased level of root lipid peroxidation in Cd treated maize and cowpea seedlings was observed after 7 and 21 days of germination. Albeit, the level of lipid peroxidation in the root of Cd treated maize was significantly higher than that of cowpea, an indication that cowpea may be more tolerant than maize to Cd toxicity. The treatment of plant with, concentrations of EDTA (0.5 and 1.0 mM) failed to decrease the Cd induced, but increased the level of root lipid peroxidation. These results indicate that EDTA (0.5 mM and 1.0 mM) could be used for the treatment of Cd toxicity in plants; although, EDTA did not totally protect cowpea seedling from oxidative stress.Key words: Heavy metal, phytoremediation

Synthesis, characterization and antibacterial studies of metal complexes of sulfadiazine with N-alkyl-N-phenyldithiocarbamate

Co(II), Cu(II), Pd(II) and Pt(II) complexes of 4-amino-N-(2-pyrimidinyl)benzene sulfonamide (sulfadiazine) with some N-alkyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis, conductivity measurements, UV-Vis and FTIR spectroscopy. The complexes are formulated as four coordinate MN2S2 species in which the metal ions are coordinated to one molecule of sulfadiazine through the pyrimidinyl and sulfulnamido nitrogen atoms and one molecule of dithiocarbamate through two sulfur atoms with both molecules acting as bidentate chelating ligands. The in vitro antibacterial activities of the complexes and sulfadiazine were evaluated against eight bacteria strains using the agar well diffusion method. The metal complexes showed varied antibacterial properties and their minimum inhibitory concentration (MIC) and maximum bactericidal concentration (MBC) were determined. KEY WORDS: Sulfadiane, Dithiocarbamate, Metal complexes, Antibacterial, Drug resistance Bull. Chem. Soc. Ethiop. 2013, 27(1), 77-84.DOI: http://dx.doi.org/10.4314/bcse.v27i1.

Intermolecular interactions between the SH3 domain and the proline-rich TH region of Bruton’s tyrosine kinase

AbstractThe SH3 domain of Bruton’s tyrosine kinase (Btk) is preceded by the Tec homology (TH) region containing proline-rich sequences. We have studied a protein fragment containing both the Btk SH3 domain and the proline-rich sequences of the TH region (PRR-SH3). Intermolecular NMR cross-relaxation measurements, gel permeation chromatography profiles, titrations with proline-rich peptides, and 15N NMR relaxation measurements are all consistent with a monomer–dimer equilibrium with a dissociation constant on the order of 60 μM. The intermolecular interactions do, at least in part, involve proline-rich sequences in the TH region. This behavior of Btk PRR-SH3 may have implications for the functional action of Btk

Introducing Misoprostol for the Treatment of Incomplete Abortion in Nigeria

Despite legal restriction, induced abortions and resulting complications are common in Nigeria. Misoprostol administration for incomplete abortion was introduced in 3 Nigerian hospitals. The feasibility of the hospitals, patient and provider acceptability were assessed using questionnaire and interview guides administered to 205 women and 17 providers respectively. Amongst the women, 194 (95%) were satisfied and very satisfied with misoprostol, 176 (86%) would choose misoprostol again if another incomplete abortion occurred and 191 (93%) would recommend it to another woman in a similar situation. Providers were highly satisfied with misoprostol. The ease of use and ability to redirect surgical resources to more complicated issues were positive features cited by them. The providers agreed that integration of misoprostol was straightforward and required few resources. Therefore, misoprostol for incomplete abortion is safe, efficacious and acceptable to providers and patients. In remote areas of Nigeria with limited post-abortion care (PAC), misoprostol administration is an important potential PAC treatment modality. Features of misoprostol-low cost, room temperature stability, and ease of introduction-render it an important treatment option, particularly in low resource and rural settings

Addressing operational complexities through re-inventing leadership style:A systemic leadership intervention

This research investigates leadership practice in private organisations in Nigeria. It focuses on learning about theapplication of leadership styles to address operational complexities in organisations. The research is based on acase study of a commercial livestock farm in Nigeria using systemic intervention as the methodology. Datacollection tools, such as a workshop, semi-structured interviews, boundary setting and participant observation,were applied. Key leadership issues identified in the case study were addressed via the creation of an effectiveapproach from different leadership underpinnings. Part of thefindings is the difficulty in sustaining the imple-mentation of a particular leadership style(s) due to unstructured nature of complexities involved in the deter-mination of suitable leadership style at different stages of the research. The research wrapped up with thesuggestion for further research on systemic leadership intervention to consider exploring the public sector, as wellas the need to further review on the use of CATWOE in the research process, to avoid the occurrence of mar-ginalisation in its apllication

ATPase mechanism of the 5'-3' DNA helicase, RecD2: evidence for a pre-hydrolysis conformation change

The superfamily 1 helicase, RecD2, is a monomeric, bacterial enzyme with a role in DNA repair, but with 5'-3' activity unlike most enzymes from this superfamily. Rate constants were determined for steps within the ATPase cycle of RecD2 in the presence of ssDNA. The fluorescent ATP analog, mantATP (2'(3')-O-(N-methylanthraniloyl)ATP), was used throughout to provide a complete set of rate constants and determine the mechanism of the cycle for a single nucleotide species. Fluorescence stopped-flow measurements were used to determine rate constants for adenosine nucleotide binding and release, quenched-flow measurements were used for the hydrolytic cleavage step, and the fluorescent phosphate biosensor was used for phosphate release kinetics. Some rate constants could also be measured using the natural substrate, ATP, and these suggested a similar mechanism to that obtained with mantATP. The data show that a rearrangement linked to Mg(2+) coordination, which occurs before the hydrolysis step, is rate-limiting in the cycle and that this step is greatly accelerated by bound DNA. This is also shown here for the PcrA 3'-5' helicase and so may be a general mechanism governing superfamily 1 helicases. The mechanism accounts for the tight coupling between translocation and ATPase activity