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文章
Zhang Yanying, Zhang xiangzhai, Jia Qinghui, Li Yunyu, Li Peiguo*, Zhang Wenxiang and Chen Juan
Abstract: Total RNA of Eimeria tenella drug-resistant strain from Tangshan was extracted with Trizol. Differential-display reverse transcription- polymerase chain reaction (DDRT-PCR) was established by 3 anchored primers and 20 arbitrary primers. The products of polymerase chain reaction (PCR) were analyzed on the denaturing polyacrylamide gels by silver-straining. Ten differential bands were excised from the gels and reampilfied with the same sets of primers. The products were purified and ligated with PMDTM18-T Vector, and then the dot-blot hybridization, sequence analysis and homology comparison. The results showed that through comparison of the nucleotide acid sequence, the similarity was 99% among the sequence S116 from mRNA of Tangshan multiple-resistant strain with the sequence 882 bp lengths in the first chromosome of E.tenella in Genebank and Sanger, which was an unknown protein. This study paved the way for cloning the full-length cDNAs (Complementary Deoxyribonucleic acid) and finding the molecular mechanism about the drug-resistance of E.tenella.[...] Read More.
Keywords: Chicken, Eimeria tenella, mRNA differential display polymerase chain reaction (PCR), denaturing polyacrylamide gel, gene cloning.
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文章
Cortes-Sánchez Alejandro, Hernández-Sánchez Humberto and Jaramillo-Flores María*
Abstract: Ustilago maydis FBD12 is a phytopathogenic fungus that grows in submerged environments and produces different metabolites, such as glycolipids (biosurfanctants), cyclic peptides, tryptophan derivatives, and enzymes. Biosurfactants are molecules with a high surface activity, as well as emulsifying properties. They are secondary metabolites whose main physiological role is to support the growth of microorganisms in water-immiscible substrates, through the reduction of the superficial tension of the interface. In the present study, the production of glycolipids by U. maydis FBD12 was investigated during its growth in fish and soy oils. The highest growth was observed at the 7th day of incubation with 16.8 and 7.25 g/L of biomass in fish and soy oils, respectively. An amount of 18.3 mg/100mL of glycolipid extract was obtained for fish oil, with an antioxidant capacity of 350 µMol ET/mL and a reduction in the minimum inhibitory concentration (MIC) towards S. aureus and S. Typhimurium of 25%. MIC decreased in 75% for Staphylococcus aureus when lipase was added to the fish oil culture medium. For soy oil, 9.6 mg/100mL of glycolipids were obtained with an antioxidant capacity of 232.5 µMol ET/mL and a MIC reduction of 25% in soy oil, which decreased 50% with the addition of lipase.[...] Read More.
Keywords: Antimicrobials, biosurfactants, lipase, reductors sugars, secondary metabolites, Ustilago.
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Bahareh Rajaei, Seyed Davar Siadat,*, Mohamad Reza Razavi, Mohammad Reza Aghasadeghi , Nahid Sepehri Rad, Farzad Badmasti, Somieh Khanjani Jafroodi, Taraneh Rajaei, Arfa Moshiri and Saifuddin Javadian
Abstract: A total eighty four epidemiologically unrelated clinical isolates of Salmonella enterica serovars were subjected to antimicrobial susceptibility testing and molecular detection of class 1 and 2 integrons. Eleven isolates (13.1%) which were resistant to at least 4 groups of antimicrobial agents considered as MDR (multidrug resistant) Salmonella serovars. PCR assays detected intI1 and intI2 genes in 50 (59.5%) and 14 (16.7%) of Salmonella clinical isolates respectively. Emergence of MDR Salmonella serovars demonstrates that antimicrobial selection pressure is widespread and increased distribution of integron carrying gene cassettes which confer resistance to different antibiotics confirms that integron-mediated antibiotic resistance is considerable in our clinical settings.[...] Read More.
Keywords: Salmonella spp., integron, multidrug resistance (MDR).
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文章
Daochen Zhu,*, Chenxiang Wang, Shoko Hosoi-Tanabe, Weimin Zhang and Shinichi Nagata
Abstract: Hydroxyectoine and ectoine were accumulated in the moderately halophilic bacterium Halomonas ventosae DL7 as dominant compatible solutes in response to the external thermo- and osmo-stresses (30-42°C, 1-3 M NaCl). As the byproduct of ectoine, hydroxyectoine was directly converted from ectoine mediated by the ectoine hydroxylase in DL7, and the hydroxylase gene sequence was obtained by PCR. Further, the activity of ectoine hydroxylase of strain DL7 cells in vitro was determined at 30 to 42°C, and the thermo-stress conduce the inhibition of this enzyme activity. In addition, DL7 cells showed similar growth level when grown in presence of same level ectoine or hydroxyectoine (1 mM) in medium with high salinity (2-2.7 M NaCl). However, the presence of hydroxyectoine showed higher growth level than ectoine when DL7 cells were incubated at 42°C. The results showed that the alteration of temperature instead of salinity stress obviously stimulated the expression of ectoine hydroxylase, but inhibited its activity, and hydroxyectoine with ectoine together played an important role as thermo- and osmo-protectants in strain DL7 to cope with high temperature and salinity environment.[...] Read More.
Keywords: Halomonas ventosae DL7, compatible solutes, hydroxyectoine, ectoine hydroxylase, thermo-stress, osmo-stress.
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文章
Akinlabi O. Ogunleye* and Steve A. Carlson
Abstract: Occurrence and spread of Salmonella genes encoding AmpC and extended-spectrum beta-lactamases (ESBL) is a major public health problem worldwide. These genes have been identified in Salmonella serotypes all over the world yet there is paucity of reports on these genes in Nigeria, despite the phenotypic evidence of resistance to beta- lactam drugs. The current work used a multiplex PCR to identify beta-lactam resistance genes in five Nigerian-origin Salmonella isolates exhibiting resistance to third-generation cephalosporins. The isolates included four strains isolated from septic poultry (two strains of Salmonella enterica serotype Kentucky and two strains of presumptive S. enterica serotype Pullorum) and one S. enterica serotype Give isolated from one of two hundred asymptomatic pigs. The predominant genes found in these Nigeria serotypes include: TEM, SHV, GES, OXA-2, ACCM, FOX, ECBM and DHAM. The presence of these plasmid-borne genes underscores the potential health risk of antibiotic resistance transfer from food animals to human in Nigeria because third-generation cephalosporin drugs are still the drug of choice in treating life-threatening systemic infections in Nigeria.[...] Read More.
Keywords: Salmonella, 3rd generation cephalosporin, multi-resistant, Nigeria.
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Shi Lin Li, Shun Li Feng, Zeng Ting Li, Hui Xu, Ying Peng Yu, Dai Rong Qiao and Yi Cao*
Abstract: We established a new screening method for oleaginous fungus, which was consistent with sudan black B stained but more convenient and faster. 11 strains of oleaginous fungi that utilize D- xylose were isolated from the soil of Qinghai Plateau by this method. These strains belong to 7 species by molecular identifying, they are Tilletiopsis albescens, Backusella ctenidia, lectosphaerella sp., Gibberella fujikuroi, Fusarium sp. Aspergillus fumigatus and Penicillium decumberns; 4 of which were the first time found to produce lipids, they are Tilletiopsis albescens, Backusella ctenidia, lectosphaerella sp. and Gibberella fujikuroi. In addition, these oleaginous fungi could accumulate certain microbial oil by fermenting D-xylose and carboxymethyl cellulose (CMC), whose composition is similar to vegetable oil and can be converted to biodiesel. These microorganism species that may use cheap lignocellulose to produce microbial oil, it can pave lane for biodiesel production with low cost.[...] Read More.
Keywords: Oleaginous fungi, D-xylose, carboxymethyl cellulose, biodiesel.
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文章
Masumeh Abbasi, Saman Mahdavi* and Sedigheh Mehrabian
Abstract: Free radicals are produced during oxidative metabolism in body and they can attack all components of cells and cause cellular changes and early aging. Antioxidant materials role for balance maintenance in cells has currently attracted more attention. The aim of this study is investing of antimutation effect of Artemia, cyst and decapsulated egg extract by Ames test and Salmonella typhimurium TA 100 strain. These extract prevent reverse mutation caused by carcinogenic materials. In comparison with positive controls (sodium azid, KMno4, cresol) and negative control (distilled water) antimutagenicity properties of Artemia was evaluated and confirmed. In addition, the value of astaxanthin in those extracts was assayed. For quality analysis and separation of astaxanthin, we used thin-layer chromatography (TLC) chromatography and column chromatography, respectively. Then, the presense of astaxanthin in these extracts was confirmed by spectrometer IR test. The results showed that antimutagenicity properties of Artemia urmiana are the same with other salty water Artemia. Antimutagenicity and anticarcinogenicity properties in decapsulated egg, dried Artemia and cyst are 85, 70 and 100%, respectively.[...] Read More.
Keywords: Ames test, anticarcinogenicity, antioxidant, Artemia urmiana, Salmonella typhimurium TA 100.
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Full Length Research Paper
Abstract: BEAUVERIA BASSIANA is an insect pathogenic fungus and is currently being exploited as an effective commercial mycoinsecticide. Solid state fermentation is the most efficient way to mass produce B. BASSIANA conidiospores on solid substrates. Statistical optimization strategy was adopted to maximize the conidia production through solid state fermentation. Four substrates viz., rice (polished), crushed sorghum, wheat bran and rice bran at variable moisture content and yeast extract concentration were used. A full factorial central composite design was used to design the experiment and response surface method was used to study the optimal parameters required for large scale production. Optimization of the two most important factors like moisture content and yeast extract concentration at varied levels conferred best conidial yield of 28.8 × 109 /gm for the mixed substrate rice + wheat bran at 35% moisture content and 1.5% yeast extract concentration.[...] Read More.
Keywords: Beauveria bassiana, central composite design, conidiospores, response surface methodology, solid state fermentation.
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Full Length Research Paper
Abstract: We investigated the effect of dietary carbohydrate supplementation on CANDIDA ALBICANS colonization using an animal model and a CANDIDA strain with both high phospholipase and proteinase activity. Normal and immunosuppressed mice were inoculated intraperitonially with C. ALBICANS and were allowed free access to drinking water supplemented or not with glucose. Blood and different organs including liver, spleen, lung and kidney were aseptically collected every 72 h post-infection. The presence and the growth of C. ALBICANS in blood and each organ were investigated. We also performed histopathologic investigations on each organ to assess tissue structure, the presence of C. ALBICANS, and its form (blastospore or hyphae). The results showed that on the third day post-inoculation, the cfu of C. ALBICANS per organ was significantly higher in mice inoculated by C. ALBICANS and receiving the glucose as supplement (433 cfu/liver) comparatively to the group receiving C. ALBICANS only (140 cfu/liver). Histological analysis revealed the presence of CANDIDA cells in blastospore and hyphal form, particularly in the CANDIDA-infected glucose-supplemented mice whose livers displayed oedema and leukocyte infiltration with a high density of polymorphonuclear cells. Overall results indicate that dietary glucose supplementation leads to higher rates of CANDIDA growth and invasion. This suggests that glucose restriction could be a possible way to control C. ALBICANS pathogenesis IN VIVO.[...] Read More.
Keywords: Candida albicans, glucose, immunosuppressed mice, experimental infection.
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文章
Hongbo Wang, Junyi Zhou, Mingkai Xu*, Huiwen Zhang and Chenggang Zhang
Abstract: Bacterial superantigen Staphylococcus aureus enterotoxin C2 (SEC2) is a very potent activator of T cells. Previous crystal studies on SEC2 showed that residue Tyr26 which is located near the T cell receptor (TCR) binding sites could potentially participate in T cell activating. In SEC1, a superantigen highly homologous to SEC2, the residue Val26 played a critical role in stimulating certain V expansion. Moreover, residues 20, 22 and 26 in SEC1 determined its serologic cross-reaction. In order to investigate the potential roles of Tyr26 in SEC2, two SEC2 mutants SEC2 (Y26V) and SEC2(Y26A) were constructed by site-directed mutagenesis. The activities and toxicities of the two mutants were determined both in vivo and in vitro. Results showed that both SEC2 (Y26V) and SEC2 (Y26A) remained potent immune stimulating activities compared with native SEC2. SEC2 (Y26V) had a decreased pyrogenic effect on rabbit model. Both of the two mutants had significantly decreased binding affinities to anti-SEC2 IgG. Our result indicated that Tyr26 is a critical site for the serological characters of SEC2 rather than for its superantigen activity. This may also provide an insight in constructing a novel mutant to substitute native SEC2 in cancer immunotherapy avoiding being neutralized by anti-SEC2 IgG in vivo.[...] Read More.
Keywords: Staphylococcal enterotoxin C2, Site-directed mutagenesis, superantigen, serological, property.
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