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N.Khodayari, F.Mollaamin , M. Monajjemi
Abstract: Understanding the structure and dynamics of a docosa hexaenoic acid (DHA) containing phospholipid monomer within membranes is essential for recognizing the bilayer function in central nervous system. It has been recognized that the electrical impulses in nerve cells arise from the movement of electrical charges in the form of ions across the plasma membrane. In this study, we have modeled a novel DHA-containing phosphatidylcholine (PC) found in a marine single cell eukaryote, “Schizochytrium sp F26-b” and we were focused on understanding the physico-chemical nature of K+ and Na+ movement toward DHA-containing phospholipid through its structural changes. To know more about the temperature dependence of the structural stability of 1-pentadecanoyl-2-docosahexaenoyl-sn–glycerol-3-phosphocholin frequently calculations have been carried out at different biological temperatures and the plotted graphs of energy values at all employed temperatures have been analyzed. Our findings confirmed the usefulness of Quantum chemical calculations for determination of dynamics of a phospholipid and prediction of their biological activity in bio-membranes.[...] Read More.
Keywords: Docosahexaenoic acid-containing phospholipid, nerve cell membranes, K+ and Na+, Ab initio.
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Jingfa Wang, Jian Li, Jiankang Cao and Weibo Jiang*
Abstract: To learn the antifungal effects of neem seed kernel extract (NE) on the post harvest diseases, pathogens of Monilinia fructicola, Penicillium expansum, Trichothecium roseum and Alternaria alternate isolated from the infected fruit were treated with NE in vitro. Results showed that growth of the four pathogens could be significantly (P < 0.05) reduced by NE. The diseases in fruit of plum (Prunus salicina) or Yali pear (Pyrus bertschneideri) inoculated with the pathogens could be prevented remarkably by treated fruit with NE.[...] Read More.
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Ali Bayane*, Bréhima Diawara, Robin Dauphin Dubois, Jacqueline Destain, Dominique Roblain and Philippe Thonart
Abstract: Five spore-forming bacteria producer of lactic acid were isolated from soils sampled in the vicinity of poultry farms in Burkina Faso. All isolates were Gram-positive, motile, mesophilic, facultative anaerobic, catalase positive rods, and with L(+) lactic acid production. The isolates have been characterized and identified by a polyphasic approach, combining various phenotypic and genetic characteristics. The 16S-rDNA-sequence analyses revealed the membership of two isolates to the genus Bacillus and the three other to the genus Paenibacillus. The physiological and biochemical analyses showed that the isolates were quite different from known spore forming lactic acid bacteria. Several relevant technological properties were observed, particularly the resistance of the isolates to bile salts and acidic conditions, even the productions of amylolytic and proteolytic enzymes, which could make them good candidates for certain technological applications such as food fermentations and probiotic formulations. Furthermore, the isolation of these microorganisms in the vicinity of farms reinforces the feasibility of their involvement in animal feedstuffs preparations. In conclusion, this work shows an important diversity within the spore-forming lactic acid bacteria and confirms the conclusions of previous works, which have already shown that the SFLAB (Spore Forming Lactic Acid Bacteria) were good candidates for food fermentation and the probiotic formulations.[...] Read More.
Keywords: Lactic acid, spore-forming bacteria, biodiversity, bacillus, 16S rDNA.
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S. K. Leong, Z. Latiffah* and S. Baharuddin
Abstract: Genetic diversity of Fusarium oxysporum f. sp. cubense (FOC) isolates were analyzed using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), random amplified microsatellites (RAMS) and restriction fragment length polymorphism of Intergenic Spacer (RFLP-IGS) . The three molecular techniques showed intraspecific variations and the banding patterns generated using each technique were highly variable. UPGMA cluster analysis of the combined data of the three techniques showed 35.7 - 100% genetic similarity among the FOC isolates. Based on the dendrogram, most of the isolates including four isolates from Indonesia were clustered together in two main clusters. Sequence analysis of TEF-1 gene of some of the isolates of FOC using parsimony and distance methods also showed intraspecific variations. The highly variable banding patterns shown by using molecular methods supported the hypothesis that the isolates of FOC co-evolved with the edible bananas and dissemination of the pathogen was probably through infected rhizomes.[...] Read More.
Keywords: Fusarium oxysporum f.sp. cubense, enterobacterial repetitive intergenic consensus PCR, random amplified microsatellites, restriction fragment length polymorphism of Intergenic Spacer.
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Grillo Joseph Adebayo* and Lawal Adekunle Kolawole
Abstract: Fresh white bread and ‘eba’ (a carbohydrate; > 80% starch, indigenous staple food in southern Nigeria) were purchased from traders in Lagos, Nigeria and stored under aseptic conditions in the laboratory at room temperature (27 ± 2°C) (11 h of darkness and 15 h of daylight) for duration of 144 h, during which samples were analyzed at 48 h intervals for fungal population using the plate count technique. The sensitivity of the spoilage fungi to aqueous and methanol extracts of leaves of Thaumatococcus danielli and Megaphrynium macrostachyum was determined using the broth dilution method. Fungal populations increased with hour of storage. For bread, Penicillium sp was dominant throughout with average populations of 2.0 x 101 and 8.01 x 106 cfu/g at 0 and 144 h, respectively, while Mucor sp was dominant in eba with average populations of 1.0 x 101 and 9.5 x 106 cfu/g at 0 and 96 h, respectively. For T. danielli, while the methanol extract had greater activity against the spoilage fungi than the aqueous extract, the reverse was observed for M. macrostachyum. The lowest minimum inhibitory concentration (MIC) of T. danielli was 25 mg/ml of the methanol extract against Saccharomyces cerevisiae and Saccharomyces chevalieri and its lowest minimum cidal concentration (MCC) was 50 mg/ml of the methanol extract against S. cerevisiae and Penicillium sp. For M. macrostachyum, the lowest MIC and MCC were 25 and 50 mg/ml of the aqueous extract respectively against S. chevalieri. The results highlight the potential of extracts of T. daniellii and M. macrostachyum as sources of alternative natural preservatives of bread and ‘eba’. [...] Read More.
Keywords: Thaumatococcus danielli, Megaphrynium macrostachyum, minimum inhibitory concentration, minimum cidal concentration.
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文章
Wan-Li Sun, and Wei-Yi Tao*
Abstract: In this work, the cell growth and ethanol productivity was tested for lignocellulosic biomass sugars of overliming-detoxified and NaOH-neutralized rice straw acid hydrolysate by using Candida shehatae CICC 1766. When the acetic acid reached 3 g/L in defined xylose medium, the final ethanol concentration was 33% of that in the medium without acetic acid addition. C. shehatae CICC 1766 could bear lower pH (ethanol yield 13.5 g/L at pH 4.0) in overliming-detoxified hydrolysate. At the optimal pH 5.0 the ethanol yield attended to 16.1 g/L. Ethanol yield in NaOH-neutralized hydrolysate was 13.7 g/L which is better than in overliming-detoxified hydrolysate (7.0 g/L) . It suggested that NaOH-neutralized hydrolysate could be directly fermented by using C shehatae CICC 1766.[...] Read More.
Keywords: Rice straw, Candida shehatae, hemicellulose hydrolysate, ethanol fermentation.
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Hajlaoui Hafedh*, Ben Abdallah Fethi, Snoussi Mejdi, Noumi Emira and Bakhrouf Amina
Abstract: The chemical composition and the antibacterial activity of the essential oil of Mentha longifolia L. ssp longifolia are being investigated in the present work. The minimal inhibitory concentration (MIC) of this oil against four gram+ and gram- reference bacteria including Salmonella typhimurium LT2, Escherichia coli ATCC 35218, Microccus luteus NCIMB 8166 and Staphylococcus aureus ATCC 25923 was used to study the morphological alteration of bacterial wall cell visualized by atomic force microscopy (AFM). The chemical analysis of the essential oil showed the presence of 34 compounds. The most important ones were: menthol (32.51%), menthone (20.71%), pulegone (17.76%), 1,8-cineole (5.61%), terpineol-4 (4.87%) and piperitone (2.16%). The MIC for bacteria ranged from 0.19 to 1.56 mg/ml. We found that M. longifolia (Menthol chemotype) has a high antibacterial effect. Cell wall of the tested bacteria was damaged at MIC concentrations. This susceptibility is more accentuated in S. typhimurium and E. coli (rod bacteria), whereas the damage is less important in coccoid bacteria (S. aureus and M. luteus).[...] Read More.
Keywords: Mentha longifolia, essential oil, Staphylococcus aureus, Microccus luteus, Escherichia coli, Salmonella typhimurium, cell morphology, atomic force microscope.
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B. Usharani and M. Muthuraj*
Abstract: Production and partial purification of protease enzyme by Bacillus laterosporus was the aim of this study. B. laterosporus was allowed to grow in shake flask broth culture for purpose of inducing protease enzyme. The protease enzyme was purified by ammonium sulfate precipitation followed by dialysis and further concentrated by Amicon tubes. After concentration, the protein was subjected to 12% Zymogram gel with gelatin and the molecular weight of the protease enzyme was 15 kDa. The protease activity increased as there was increase in enzyme concentration; optimum substrate concentration (starch) was 1.0% (w/v); an optimum incubation temperature was 40°C. Purified protease enzyme had a maximum activity at pH 7.0 of phosphate buffer and the optimum incubation time was 24 h. The protease isolated from B. latrosporus is a mesophilic protease. It is stable at pH 7, at 40°C temperature, and this enzyme can be exploited commercially.[...] Read More.
Keywords: Bacillus laterosporus, PMSF, -mercaptoethanol, protease, fermentation.
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Venant Nihorimbere, Marc Ongena*, Hélène Cawoy, Yves Brostaux, Pascal Kakana, Emmanuel Jourdan and Philippe Thonart
Abstract: The biocontrol potential of Bacillus subtilis S499 was evaluated on tomato in open field sites in low altitude area of the plain of Imbo in Burundi. This strain was tested in order to reduce the impact of an important fungal disease giving rise to large losses in local plantings. The causing pathogen was isolated from diseased leaves at different locations in the fields and identified as Fusarium most probably related to the semitectum species according to the fermentation profile, morphology and gene homology. Results of assays performed in two successive years on the same site indicated that bacterial treatment on seeds significantly increased growth and fruit yield of tomato plants and also provided a high level of protection against the disease caused by this Fusarium pathogen. This is the first reported study on this disease and based on the data collected, B. subtilis S499 may represent an effective solution as biocontrol agent where other chemical options have failed.[...] Read More.
Keywords: Bacillus subtilis, biocontrol, Fusarium disease, tomato plants.
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Q. Xuan, F. K. Bao, H. M. Pan and A. H. Liu*
Abstract: Eighteen fungal endophytes strains parasitizing the famous Chinese medicinal plant Paris polyphylla Smith var. yunnanensis (Franch.) Hand. Mazz were isolated from surface-sterilized plant tissues, such as rhizome, root, stem, leaf and flower. The effect of endophytes on the growth of human pathogenic microbes was evaluated in vitro, using disc diffusion assay. According to the characteristics of cultures and DNA sequences, the WRF7 and WRF7’ belonged to the species Penicillium chrysogenum. The extract of WRF7’ inhibited a broad range of human -pathogenic bacteria, but that of WRF7 almost had no similar effect. And the metabolites of WRF7’ could not stop the growth of test fungus Candida albicans. The study indicates that P. chrysogenum becomes fungal endophyte of Paris polyphylla Smith var. yunnanensis and its isolate WRF7’ makes metabolites that are inhibitory to all test bacteria in vitro. Therefore, the host plant suppressing pathogens owing to its endophytes and inhibitory mechanisms of endophytes to test bacteria and fungi are different.[...] Read More.
Keywords: Fungal endophyte, Paris polyphylla Smith var. yunnanensis (Franch.) Hand. Mazz, isolating, identifying, antibacterial ability.
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