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Ali Ellafi*, Fethi Ben Abdallah, Rihab Lagha and Amina Bakhrouf
Abstract: In this study, we incubated four strains of Shigella in seawater microcosms (at room temperature and at 4°C) for eight months and we studied the alteration of their morphologic and outer membranes proteins. The starved cells showed an evolution to the filterable minicells state capable to pass membrane pore size 0.45 µm. In addition, the atomic force micrographs showed a reduction of the cells size and an evolution to coccoid-shapes. Outer membrane proteins patterns of stressed bacteria did not changed too much and these modifications were manifested by the appearance of one new band.[...] Read More.
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Christy E. Manyi-Loh, Anna M. Clarke and Roland N. Ndip,*
Abstract: Honey, a natural product of very high nutritive value is made when the nectar (floral) and sweet deposits from plants (non floral) are gathered, modified and stored in the honeycombs by honeybees of the genera Apis and Meliponini. Its composition and quality vary greatly with the botanical source of nectar as well as environmental and climatic conditions. Depending on its quality, honey can contribute to the health and nutritional status of humans. These beneficial actions have been ascribed to its antimicrobial, anti-inflammatory and anti-oxidant potential. Interestingly, honey is gradually receiving attention as a complementary and or an alternative source of treatment in modern medicines. It is active against antibiotic-sensitive and antibiotic-resistant strains of micro-organisms and has the potential not to select for further resistant strains.[...] Read More.
Keywords: Honey, natural product, drug, food.
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Kavous Ayazpour, Kamaruzaman Sijam*, Ganesan Vadamalai, Hawa Jaafar
Abstract: Citrus tristeza virus (CTV) is the most important viral disease of Citrus spp. and has a worldwide distribution. Results of ELISA and PCR showed that all Citrus varieties including Fortunella sp., Citrofortunella microcarpa and Citromelo in major citrus growing areas of Malaysia had a high infection rate with CTV. In most areas, pomelo however was free of infection, but in Cameron Highlands, we found some strains of CTV that were severe to Citromelo and pomelo. Phylogeny studies revealed that these strains were similar to CTV isolates from China and Japan and were very different from CTV isolates from USA and New Zealand.[...] Read More.
Keywords: Citrus tristeza virus, phylogeny analysis, strain, CP gene, Malaysia.
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J. Kassongo and C. A. Togo*
Abstract: Humankind has always been engaged in a relentless quest for energy to drive daily activities. However, most of the existing conventional strategies of tapping the environment are expensive and polluting. A nascent microbial fuel cell technology, relying on the degradation of wastewater such as cheese whey with the subsequent release of electricity, is thus the focus for sustainable energy. It is therefore important to gain an in-depth knowledge of the biology in these devices and possible avenues of enhancing power generated from them. In an effort to increase power from whey-driven microbial fuel cells (MFCs), graphite sheet anodes were incubated in whey for two months then reused in four cycles of seven days each in MFCs. The concomitant remediation was additionally determined. Highest power density (390 ± 21 W/m2) was obtained during the third reuse cycle with a coulombic efficiency of 0.25%. The highest tCOD removal (44.6%) was however, noted during the second cycle. The performance of reactors depended on the number of reuse cycles with the third cycle proving to be the best after which there was a decline in power density. In addition, molecular analyses of anodophilic microorganisms showed the presence of three species related to strains from Lactobacillus helveticus (85% identity), Proteus mirabilis (96%) and Escherichia coli (96%). Therefore the necessity of biofilm build up should take into account the limitation of maximum number of reuse cycles where the flora will be performing at its best.[...] Read More.
Keywords: Cheese whey, green power, microbial fuel cell, biofilm, bioremediation.
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Manuela Reyes-Estebanez, Elizabeth Herrera-Parra, Jairo Cristóbal-Alejo, Gabriela Heredia-Abarca, Blondy Canto-Canché, Irma Medina-Baizabal and Marcela Gamboa-Angulo*
Abstract: Forty seven fungal strains were isolated from plant debris in the tropical regions of Mexico, where fifteen of them were identified to species and twenty two to genus level. All isolates were grown in fermented rice and their EtOAc extracts screened against ten targets, four bacteria (Bacillus subtilis, Erwinia carotovora, Staphylococcus aureus and Xanthomonas campestris), the yeast Candida albicans, three phytopathogenic fungi (Alternaria tagetica, Colletotrichum gloeosporioides and Fusarium oxysporum), the Oomycete Pythium aphanidermatum and the nematode Meloidogyne incognita. Antimicrobial activity was detected in 18 isolates against at least one of the target strains tested. Seven of these isolates with broad spectrum activity, which were defatted and their minimum inhibitory concentrations (MICs) were determined by microdilution assay. The greatest antagonistic action was produced by Cylindrium elongatum with broad spectrum activity while Corynespora cassiicola and Memnoniella sp. MR33 showed moderate antimicrobial properties. On other hand, in vitro nematotoxic activity was clearly detected only in Selenosporella sp. GH26 with 91 (LD50) and 147 µg/ml (LD90). This is the first report on the isolation and biological evaluation of anamorphic fungi from some Mexican tropical regions, demonstrating their potential as a source of biologically active natural metabolites for use in future applications in agriculture or pharmacy.[...] Read More.
Keywords: Anamorphic fungi, antimicrobial, Corynespora, Cylindrium, fungal extracts, nematicide, Selenosporella, Yucatan peninsula.
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Yebpella G. G., Adeyemi Hassan M. M., Hammuel C., Magomya A. M., Agbaji A. S. and Okonkwo E. M.
Abstract: The phytochemical screening and comparative study of antimicrobial activity of Aloe vera extracts was carried out. The phytochemical screening revealed the following metabolites: saponins, alkaloids, glycosides, tannins, protein, and flavonoids. While cardiac glyocosides and steroids were absent. The antimicrobial activities of the gel in 10% DMSO, methanol and aqueous extracts of green rind and leaf pulp were carried against some pathogenic clinical isolates, namely, Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis and Candida albicans. The DMSO extract of the gel and the methanol extract of the green rind showed greater potency against tested microorganisms in the order B. Subtilis> S. aureus> C. albicans and S. aureus>C. albicans>B. subtilis>P. mirabilis respectively with different zones of inhibition ranging from 18 to 35 mm gel, 15 to 18 mm for leaf pulp methanol, 20 to 32 mm green rind methanol, also 12 to 14 mm and 14 to 23 mm for leaf pulp aqueous and green rind aqueous respectively. The minimum inhibitory concentration (MIC) of the extracts against organisms ranged from 6.25 to 25 mg/ml while the minimum bactericidal concentration (MBC) was within the range of 12.5 to 50 mg/ml. The study revealed that the green rind methanol extract and gel have greater medicinal potential against B. subtilis.[...] Read More.
Keywords: Antimicrobial, gel and green rind extract, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and phytochemical screening, Aloe vera.
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Zheng Rui-dan*, Su Ya-yong, Lu Yan-hui, Meng Jia-rong and Zhang Min-feng
Abstract: To investigate the intercellular adhesion molecule-1 (ICAM-1) expression in the liver and serum hepatitis B virus (HBV) DNA level in chronic hepatitis B (CHB) patients before and after interferon (IFN) treatment, a total of 51 CHB patients were recruited and treated with IFN- 1b for 6 months. The expressions of ICAM-1 and serum HBV DNA were determined at baseline and after 6-month treatment by using immunohistochemistry and real time fluorescence polymerase chain reaction (PCR). The expression of ICAM-1 in the patients with moderate to severe CHB was markedly higher that that in mild CHB patients (P[...] Read More.
Keywords: Interferon, hepatitis B, intercellular adhesion molecule-1.
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Meenakshi Goyal* and Giridhar Soni
Abstract: Three Pleurotus spp., Pleurotus florida, Pleurotus ostreatus and Pleurotus sajar-caju, were screened for cellulolytic enzyme production under submerged fermentation conditions. Of these, P. florida, was studied for optimizing medium composition, incubation period, initial pH and incubation temperature to maximize cellulolytic enzyme production. Malt extract at 0.5%, 12 day of incubation period and 1% CMC as carbon source supported maximum production of cellulases. The optimum temperature and pH for maximum production of enzymes were 35 to 40°C and 5.0 for exo-and endoglucanases and 30°C and 4.5 for b- glucosidase.[...] Read More.
Keywords: Endoglucanase, exoglucanase, fermentation conditions, b-glucosidase, medium composition.
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文章
Xiao-xing Liu
Abstract: Stochastic evolutionary game dynamics in hierarchy are very popular in economics and in management sciences. This study extends the model of stochastic evolutionary game dynamics. This paper highlights hierarchy selection model and we show that the hierarchy selection games are more stable without structures in this paper. Furthermore, an example in industrial organization is given to rationally explain the theory in this work.[...] Read More.
Keywords: Fitness, fixation probability, invasion, game theory, economics, hierarchy, evolutionary game.
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Rugen Wan, Maofeng Wang*, Sheng Zhao, Guogang Li, Yangxiao Zhou, Jiajun Li and Jinkan Du
Abstract: Cryptococcosis is a life-threatening fungal disease that usually presents as an opportunist infection in immunocompromised hosts, and Cryptococcus neoformans is the major opportunistic pathogen of cryptococcosis. Rapid diagnosis of C. neoformans and other opportunistic Cryptococcus pathogens is required to meet the clinical need for immediate treatment. Historically, negative staining with India ink has been used to identify Cryptococcus. Another staining method utilizes Alcian blue, a dye that reacts selectively with C. neoformans, but not other Cryptococcus species. To overcome these limitations, we developed a new staining method for rapid identification of Cryptococcus using a novel, patent pending staining reagent for clinical laboratory diagnosis. Cryptococci stained with this new reagent can be conveniently counted directly via bench-top light microscopy. We also compared our novel stain with India ink and Alcian blue. Our results demonstrated that the new staining technique was superior to India ink stain for the rapid identification of Cryptococcus in clinical (and clinically mimicking) samples. Our stable and cost-effective staining reagent specifically stained Cryptococcus, highlighting its clinical applicability, particularly in developing countries due to its low cost.[...] Read More.
Keywords: Cryptococcus, cryptococcosis, specific staining, India ink staining, rapid identification.
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