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Scot E. Dowd* and Jeanette A. Thurston-Enriquez
Abstract: The potential for waterborne disease and zoonotic transmission of at least two species of human pathogenic microsporidia has heightened interest in clinical and environmental detection methods for these organisms. Detection using the polymerase chain reaction (PCR) followed by computer database homology comparison (CDHC) (PCR-CDHC) was reported previously by this research group. As a result, PCR-CDHC has been employed by many research groups around the world for species determination of human pathogenic microsporidia. To validate the CDHC speciation approach, a phylogenetic tree was generated using the small subunit ribosomal DNA sequences (SSU-rDNA) of a large number of microsporidia. An index of similarity was created and used as part of an assessment of CDHCs ability to differentiate between closely related species. Polymerase chain reaction followed by dye termination PCR sequencing and subsequent CDHC of the sequences was performed on 8 species of microsporidia including four human pathogenic strains. The four non-human pathogenic microsporidia tested by this approach were those shown by the phylogenetic analyses to be very closely related to the other human pathogenic species as determined by branch length. In all cases the CDHC approach was able to correctly identify the eight species of microsporidia evaluated. To provide an example of PCR-CDHC, a “universal” and two previously published pathogen-specific microsporidia PCR protocols followed by PCR-CDHC was conducted to assess their ability to detect naturally occurring microsporidia species in swine wastewater. Only one primer set resulted in a PCR-CDHC analysis where presumptive human pathogenic microsporidia was detected. Subsequent CDHC showed these presumptive positive PCR results were actually false positives. With the appropriate primer set, PCR-CDHC proves to be a reliable method that can be used for specific species determination of human pathogenic microsporidia in samples where non-pathogenic species may be present.[...] Read More.
Keywords: Microsporidia, Sequencing, BLAST, PCR, detection.
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文章
Filadia P. Tileva, Lyubov K. Yotova and Gerard H. Markx*
Abstract: Conditioning of cultures involves growing cells in the presence of increasing amounts of a toxic chemical. In order to investigate how conditioning affects a culture’s ability to resist new challenges, the resistance of Trichosporon cutaneum to various toxic chemicals, before and after conditioning to growth on phenol, was investigated by measuring the capacitance of cell suspensions at 0.4 MHz following a toxic challenge. The results show that cells grown on phenol are more resistant to the influence of polar aromatic toxic chemicals such as phenol (log Pow = 1.48) and benzylalcohol (log Pow = 1.1), but less resistant against less polar non-aromatic compounds such as n-octanol (log Pow = 2.9). In reverse, cells grown on glucose were found to be more resistant against n-octanol, but less so against phenol and benzylalcohol. The results indicate that cells, adapted to be more resistant to one type of substance, may become more susceptible to other compounds.[...] Read More.
Keywords: conditioning, adaptation, membrane, Trichosporon cutaneum, capacitance.
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文章
Doughari, J. H.*, Elmahmood, A. M. and Nggada, H. P.
Abstract: Due to reported cases of antimicrobial resistance by many pathogenic bacteria against many antibiotics worldwide, and the sparse nature of antimicrobial resistance data, a retrospective study was carried out on 744 isolates of Salmonella typhi obtained from 974 samples from four different hospitals in Yola, Adamawa State, Nigeria between 2001-2004 to determine the resistance pattern of S. typhi to the most commonly used antibiotics cotrimoxazole, ciprofloxacin, chloramphenicol and ampicillin. High rates of resistance was found in most of the isolates studied. Resistance rates were 92.3, 88.8, 79.6, 53.5 and 20% to amoxicillin, ampicillin, chloramphenicol, cotrimoxazole and ciprofloxacin, respectively. The high percentage resistance to the antibiotics studied could be attributed to their prevailing usage and abuse in the area under study. The implication of the high percentage resistance recorded for the antibiotics is that only ciprofloxacin will effectively treat S. typhi infections. These results call for nationwide surveillance programme to monitor microbial trends and antimicrobial resistance patterns in Nigeria.[...] Read More.
Keywords: Antibiotics, resistance, surveillance, Nigeria, Salmonella typhi.
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文章
Nmorsi O.P.G.*, Ukwandu N.C.D. and Egwunyenga A.O.
Abstract: We evaluated the antioxidant status of 148 Nigerian children with Plasmodium falciparum malaria. The mean malarial parasitaemia was 4701.05 ± 2160.53/µL. The mean antioxidant concentrations of the infected children were determined for vitamin A (12.16 ± 1 - 16 µg/dL), vitamin C (0.43 ± 0.03 mg/dL), 5 carotenes (40.96 ± 5.38 µg/dL), and vitamin E (0.45 ± 0.03 mg/dL) . The control subjects had higher mean concentrations of vitamin A (72.12 ± 3.12 µg/dL), and of the 5 carotenes (132.63 ± 22.45 µg/dL), and these differences were statistically significant (X2 = 42.86, P > 0.05 and X2 = 50.64, P > 0.05, respectively). The mean concentrations of vitamin C (1.22 ± 0.31 mg/dL) and vitamin E (1.03 ± 0.48 mg/dL) in the control children were not statistically significant when compared with their infected children (X2 = 0.34, P < 0.05) and (X2 = 0.66, P < 0.05), respectively. The relationship between malarial parasitaemia and the concentrations of vitamin E and the 5 carotenes were positively correlated (r = 0.83 and r = 0.99, respectively) . The levels of plasma vitamin A and vitamin C were negatively correlated with the malarial parasitaemia (r = -0.98, and r = -0.96, respectively). Children within their first 5 years of age had higher malarial parasitaemia (7628.42 ± 3151.42/µL) than those > 6 years (1176.58 ± 956/µL). The children between 1 - 5 years old had lower concentrations of vitamin A (8.89 ± 3.74 µg/dL) and vitamin C (0.28 ± 0.21 µg/dL), while the concentration of the 5 carotenes (44.54 µg/dL) and of vitamin E (0.50 ± 0.16 µg/dL) was higher in these children. In conclusion, the depressed levels of plasma antioxidants in the P. falciparum-infected children suggested lowered immunity of the children, which may contribute to the morbidity and mortality of malaria in our locality.[...] Read More.
Keywords: Vitamin A, vitamin C, vitamin E, antioxidants, Children, Plasmodium falciparum, Nigeria.
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Mary Anupama Palukurty*, Naveen Kumar Telgana, Hema Sundar Reddy Bora, Shiva Naresh Mulampaka
Abstract: Ethanol production using jaggery was enhanced in submerged fermentation when the effect of metal inducers was studied using the Plackett-Burman and Box-Behnken designs. Saccharomyces cerevisiae (NCIM 3288) was used as the fermenting organism. The Plackett-Burman design was used to initially screen seven of which the four elements were found to have significant effect on ethanol production. In the next stage, Box-Behnken design was used obtain concentrations of metal ion’s that may be supplemented to get maximum ethanol in during production process. It was observed that ethanol yield has increased to 94.8 from 75.4g/l when supplemented with the critical concentrations of salts provided by the model. These were as follows (g/l): FeSO4. 7H 2O 0.0036, MgSO4.7H2O 0.0033, MnCl2. 4H 2O 0.0017 and ZnSO4.7H 2O 0.0026, in the presence of 220 g/l of jaggery supplemented with (NH4)2SO4 2.612 g/l and KH2PO4 3.407 g/l, while the predicted concentration of ethanol as per the model is 95.35 g/l.[...] Read More.
Keywords: Jaggery, ethanol, Plackett-Burman design, Box-Behnken design, metal inducers.
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文章
Olowe O. A, Okanlawon B. M, Olowe R. A and Olayemi A. B
Abstract: We screened 211 clinical samples of which total of 135 Escherichia coli isolates from different human clinical specimens comprising urine, stool, wound swabs, high vaginal swabs, ear swabs and blood obtained from patients at Ladoke Akintola University Teaching Hospital, Osogbo, Osun State, Nigeria. The isolated E. coli were screened for their antibiograms and plasmid profiles. Seven antimicrobial drugs were used during the study. The prevalence of strains resistance to antimicrobials were; Tetracycline (91.6%), Ampicillin (86.7%), Sulphnamide (77.8%) and Gentamicin and Nalidixic acid which were (39.3%) and (4.1%) respectively. A total of seven antibiotic resistance profiles were obtained with over 64% of the isolates showing multi-drug resistance. Plasmids of three size ranges were detected in all of the isolates. Isolates with high multi-drug resistance profiles were found to possess multiple plasmids with large sizes in the range < 6 – 25 kb. Very large resistance levels > 85% were detected against Tetracycline, Sulphnamide, and Cotrimoxazole while Nalidixic acid showed least resistance of 4.1% among the isolates. Majority of the isolates were positive for betalactamase production when subjected to starch paper method. Key word: Escherichia coli, betalactamse, antibacteria resistance.[...] Read More.
Keywords: Escherichia coli, betalactamse, antibacteria resistance.
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文章
Dietmar Steverding
Abstract: Antigenic variation is a process by which pathogenic micro-organisms escape the immune response of their mammalian hosts. By convergent evolution, protozoal, fungal and bacterial pathogens have developed similar genetic mechanisms for true antigenic variation. In this review article, the biology, the surface antigens and their encoding genes, and the molecular mechanisms of antigenic variation of the protozoa Trypanosoma brucei, Plasmodium falciparum, Babesia bovis, Giardia lamblia, the fungus Pneumocystis carinii, and the bacteria Borrelia hermsii, Anaplasma marginale, Neisseria gonorrhoeae, Mycoplasma bovis and Campylobacter fetus are compared.[...] Read More.
Keywords: Antigenic variation, pathogens, micro-organisms, molecular mechanisms, immune evasion.
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文章
A. Mann*, Y. Yahaya, A. Banso and G. O. Ajayi
Abstract: Ethanolic extracts of the leaf, stem and root bark and the combination of the three parts of Anogeissus leiocarpus were investigated for in vitro antibacterial activity against clinical isolates of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa using agar diffusion techniques. The extracts of the plant parts showed higher antibacterial activity against S. aureus (15.80 ± 0.85) than other tested organisms. The plant parts generally were found to contain important bioactive substances such as glycosides, phenols, tannins, saponins, alkaloids, steroids, ellagic acids and anthraquinones. These agents may be responsible for the antibacterial activity of this plant. Keywords: Anogeissus leiocarpus, clinical isolates, antibacterial activity, bioactive.[...] Read More.
Keywords: Anogeissus leiocarpus, clinical isolates, antibacterial activity, bioactive.
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文章
Effat, M. M*; Abdallah, Y. A., Soheir, M. F., and Rady, M. M.
Abstract: During the winter of 2006, outbreaks of severe entritis affected many broiler farms in the AL-Fayoum governorate, south of Cairo, Egypt. To identify the causative agent(s), bacterial isolates (14) from the diseased chickens were characterized phenotypically and biochemically. All isolates exhibited characteristics of Clostridium perfringens. Subsequently, molecular typing of the bacterial isolates was performed by multiplex PCR using four sets of primers specific for the genes encoding the C. perfringens , , and toxins, respectively. A single amplicon, corresponding in size to the alpha ( ) toxin-encoding gene (approximately 402 bp), was amplified from all the bacterial isolates. It was therefore concluded that only C. perfringens type A was responsible for the disease outbreaks.[...] Read More.
Keywords: Clostridium perfringens- necrotic entritis – broiler chicken – multiplex PCR.
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文章
Doughari, J. H.* and Manzara, S.
Abstract: The active components of leaves of Mangifera indica L. were extracted using cold water and organic solvents (acetone and methanol) and were tested against Staphylococcus aureus, Streptococcus pyogenase, Streptococcus pneumoniae, Bacillus cereus, Escherichia coli, Pseudomonas aerugenosa, Proteus mirabilis, Salmonella typhi and Shigella flexnerri using the agar well (cup plate) diffusion method. Both the acetone and methanol extracts inhibited the growth of gram positive bacteria, with acetone extract exerting more activities on all the gram positive bacteria with zone of inhibition between 15 - 16 mm, and a gram negative bacterium S. typhi (14 mm) at 250 mg/ml. Whereas, water extract was not active on any of the bacterial pathogens tested at any of the concentration of the extract used. The activities of the plant extracts on the inhibited pathogens using the zone of inhibition were not as effective as the standard commercial antibacterial disks of gentamicin and erythromycin (t = 2.23, p < 0.05). Increased temperature (60 and 100°C for 1 h) had a multiplier effect on the activity of the extracts, but alkaline pH decreased the activity. Preliminary phytochemical analysis revealed the presence of tannins, glycosides, saponins and phenols. The MIC and MBC of the extracts was in the range of 12.5 - 75 and 25 - 175 mg/ml respectively. There is a basis for the traditional use of the plant as a local health remedy.[...] Read More.
Keywords: Antibacterial activity, MIC, MBC, gram-positive bacteria, gram-negative bacteria, Mangifera indica, extract.
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