5,371 research outputs found

    Phytochemical screening and susceptibility of bacteria pathogens to extracts of Evolvulus alsinoides

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    The in vitro antibacterial activity of ethanolic and aqueous extract of the whole plant (leaves and twigs) of Evolvulus alsinoides was investigated on gram-positive and gram-negative bacteria by agar well diffusion technique. The results indicate that glycosides, alkaloids, saponins, tannins, flavonoids and volatile oil were better extracted in ethanol than water. The ethanolic extract of the plant had MIC values ranging from 16mg/ml to 512.5mg/ml. The least MIC was 16mg/ml against Salmonella typhi while Bacillus cereus and Staphylococcus aureus showed the highest MIC of 512.5 mg/ml. In the aqueous extract the MIC ranged between 512.5mg/ml to >1025mg/ml. Salmonella typhi, Micrococcus luteus and Staphylococcus aureus were not inhibited by the water extract.Key words: Evolvulus alsinoides, Phytochemical Screening, Antibacterial, Activity

    Antibacterial activities of lactic acid bacteria isolated from cow faeces against potential enteric pathogens

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    Background: The addition of sub therapeutic doses of antibiotics to cattle feed for growth promotion is a contributory factor to antibiotic resistance, thus an alternative to antibiotics is needed in animal feed additives.Objective: To determine the antimicrobial activity of cow’s intestinal Lactic acid bacteria (LAB) against enteric commensals.Method: Escherichia coli, Klebsiella species (spp) and LAB were isolated from thirty different cow faecal samples and the LAB identified by partial sequencing of 16S rRNA. The antimicrobial activity of the LAB was determined against the test Escherichia coli and Klebsiella spp.Results: Five species of LAB were isolated from thirty cow faecal samples and identified as Enterococcus hirae (8), Enterococcus durans (6), Enterococcus faecium (1), Enterococcus faecalis (1) and Weissella confusa (1). Viable cells and cell free supernatant (CFS) of the LAB were able to inhibit the growth of the test organisms with the largest zone of inhibition by the viable cells being 26mm against Escherichia coli CB6 produced by Enterococcus hirae CO6A while Weissella confusa CO29M and Enterococcus hirae CO2A produced the largest zones of inhibition (26mm) against Klebsiella CB2.Conclusion: This study shows that LAB from cow faeces possess considerable antimicrobial activity against resistant Escherichia coli from the same environment.Keywords: Antibacterial activities, lactic acid bacteria, cow faeces, enteric pathogens

    Impact of electromagnetic field on the pathogenicity of selected entomopathogenic bacteria (Proteus sp. and Bacillus sp.) on tick (Rhipicephalus decoloratus)

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    The effect of exposing entomopathogenic bacteria isolated from tick (Rhipicephalus decoloratus) to variable intensities of electromagnetic field for different periods of time was examined on their pathogenicity on tick. Some bacterial isolates from the macerate of tick cadavers were used in the infection of healthy engorged ticks. Two of the bacteria tested namely Proteus mirabilis and Bacillus cereus were able to induce morbid conditions in the ticks both of which were re-isolated from the resulting tick cadavers. Re-infection of different concentrations of both entomopathogenic bacteria of ticks were carried out on the tested ticks to determine the minimum lethal concentration required for pathogenicity. The result reveals that P. mirabilis and B. cereus were able to cause disease at concentrations of 106 and 107 cfu/ml, respectively. These bacteria were then exposed to electromagnetic field with different intensities for different periods of time after which they were reinfected into healthy insects. Conclusively, the study reveals some signs of stimulation in the entomopathogenic potency of B. cereus after exposure to electromagnetic field (EMF) when compared to the control treatments while a significant reduction in the  entomopathogenic potency of P. mirabilis was recorded.Keywords: Entomopathogens, electromagnetic field, Proteus mirabilis, Bacillus cereus.African Journal of Biotechnology Vol. 12(29), pp. 4683-469

    Identification and classification of vertical chlorophyll patterns in the Benguela upwelling system and Angola-Benguela front using an artificial neural network

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    Information on the vertical chlorophyll structure in the ocean is important for estimating integrated chlorophyll a and primary production from satellite. For this study, vertical chlorophyll profiles from the Benguela upwelling system and the Angola-Benguela front were collected in winter to identify characteristic profiles. A shifted Gaussian model was fitted to each profile to estimate four parameters that defined the shape of the curve: the background chlorophyll concentration (B0), the height parameter of the peak (h), the width of the peak (&#963) and the depth of the chlorophyll peak (zm). A type of artificial neural network called a self-organizing map (SOM) was then used on these four parameters to identify characteristic profiles. The analysis identified a continuum of chlorophyll patterns, from those with large surface peaks (>10 mg m-3) to those with smaller near-surface peaks

    Brain tumor classification using the diffusion tensor image segmentation (D-SEG) technique.

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    BACKGROUND: There is an increasing demand for noninvasive brain tumor biomarkers to guide surgery and subsequent oncotherapy. We present a novel whole-brain diffusion tensor imaging (DTI) segmentation (D-SEG) to delineate tumor volumes of interest (VOIs) for subsequent classification of tumor type. D-SEG uses isotropic (p) and anisotropic (q) components of the diffusion tensor to segment regions with similar diffusion characteristics. METHODS: DTI scans were acquired from 95 patients with low- and high-grade glioma, metastases, and meningioma and from 29 healthy subjects. D-SEG uses k-means clustering of the 2D (p,q) space to generate segments with different isotropic and anisotropic diffusion characteristics. RESULTS: Our results are visualized using a novel RGB color scheme incorporating p, q and T2-weighted information within each segment. The volumetric contribution of each segment to gray matter, white matter, and cerebrospinal fluid spaces was used to generate healthy tissue D-SEG spectra. Tumor VOIs were extracted using a semiautomated flood-filling technique and D-SEG spectra were computed within the VOI. Classification of tumor type using D-SEG spectra was performed using support vector machines. D-SEG was computationally fast and stable and delineated regions of healthy tissue from tumor and edema. D-SEG spectra were consistent for each tumor type, with constituent diffusion characteristics potentially reflecting regional differences in tissue microstructure. Support vector machines classified tumor type with an overall accuracy of 94.7%, providing better classification than previously reported. CONCLUSIONS: D-SEG presents a user-friendly, semiautomated biomarker that may provide a valuable adjunct in noninvasive brain tumor diagnosis and treatment planning

    Serum C-Reactive Protein in Nigerians With Type 2 Diabetes Mellitus

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    Background: C-reactive protein is an acute-phase proteins, produce in the liver, its release is stimulated by cytokines (interleukin 6 and tumour necrosis factor alpha). Elevated level of it is a risk factor for coronary heart disease. Baseline levels of C-reactive protein in apparently healthy men and women predict long-term risk of a first myocardial infarction. Diabetics are at increased risk for coronary heart disease, data from the Framingham Study showed a two-to three-fold elevation in the risk of clinically evident atherosclerotic disease in patients with type II diabetes compared to those without diabetes. However, but data regarding CRP in Nigerian diabetic is lacking.Method: A cross-sectional study conducted among patients attending out patient clinic of the Obafemi Awolowo University Teaching Hospitals complex (OAUTHC) Ile Ife, Osun State south western Nigeria. Measurement of C-reactive protein was based on the principle of solid phase enzyme-linked immunosorbent assay (ELISA).Results: A total of 125 consecutive subjects were recruited comprising 75 patients with type II diabetes mellitus with or without hypertension and 50 apparently healthy age-and-sex comparable controls. There was a significant difference between the mean systolic and diastolic blood pressures of the patients and controls. The fasting blood glucose and C-reactive protein were significantly higher in diabetics compared to controls. There was a positive and significant correlation between FBG and CRP in both patients and controls. Conclusion: This study showed that diabetics have significantly higher serum C-reactive protein compared to the apparently controls. Also there was a positive and significant correlation between C-reactive protein and fasting blood glucose among both patients and controls
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