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Xiao Xiao, Jingling Zhang, Quanyi Zhang, Li Wang, Yafang Tan, Zhaobiao Guo, Ruifu Yang, Jingfu Qiu and Dongsheng Zhou*
Abstract: Due to the production of abundant capsular polysaccharides and or exopolysaccharides, some bacteria form mucoid and opaque colonies on solid agar medium. Polysaccharides interfere with the isolation and characterization of DNA. Extraction of polysaccharide-free DNA from the mucoid bacteria is required for genetic and biochemical studies. In this study, mucoid Vibrio parahaemolyticus and Klebsiella pneumonia were used as model organisms for comparing the effectiveness of two DNA extraction methods. The two methods were proved reproducible and cost-effective for extracting high-purity genome DNA from mucoid bacteria for further applications.[...] Read More.
Keywords: Mucoid bacteria, Vibrio parahaemolyticus, Klebsiella pneumonia, DNA isolation, polysaccharides.
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文章
Yi Zhan, Quan Xu, Hongxia Liu, Yunpeng Wang* and Jianhua Guo
Abstract: The influence of bacterial suspension concentration on biocontrol efficacies and storage stabilities of three biocontrol agents, including BACILLUS CEREUS AR156, PANTOEA ANANATIS YT11 and PSEUDOMONAS FLUORESCENS ABc9, were studied. The results indicated that biocontrol efficacy and storage stability did not increase along with the enhancement of the concentration of biocontrol agents, and 109 CFU ml-1 of the strain P. FLUORESCENS ABc9, 108 CFU ml-1 of B. CEREUS AR156 and 108 CFU ml-1 of P. ANANATIS YT11 provided the best biocontrol efficacy as 63.06, 49.55 and 52.25% respectively, and the most suitable concentration of the biocontrol agents for preservation ranged from 108 to 109 CFU ml-1.[...] Read More.
Keywords: Biological control, strain concentration, biocontrol efficacy, storage viability.
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Rong Chen, Xiaopu Yin, Chunna Yu, Qiuyan Wang, Xiaori Zhan and Tian Xie*
Abstract: The gene encoding a thermophilic group 3 alcohol dehydrogenase from Thermotoga lettingae TMO was cloned and over-expressed in Escherichia coli. The full-length DNA sequence of TlADH was 1086-bp encoding a polypeptide of 361 amino acids. Comparative and bioinformatic analysis revealed that TlADH showed high similarity to group 3 ADHs from thermophilic and mesophilic alcohol dehydrogenases, but relatively highest similarity to T. maritime 1, 3-propanediol dehydrogenase. The optimal pH-values of butanol oxidation and butylaldehyde reduction of TlADH were 11.9 and 6.0, respectively. Kinetic parameters of the enzymes showed TlADH preferred NADP+ to NAD+ as a cofactor. TlADH can catalyze a range of primary alcohols oxidation, while it was inactive towards branched-chain alcohols and cyclitol. TlADH also can reduce aldehydes to corresponding alcohols, including aliphatic and aromatic aldehydes. It showed higher activity of aldehyde reduction than that of alcohol oxidation that may be relative to reactive aldehyde detoxification in cell metabolism. In the case of external ions addition we found a 5.23-fold increase in reaction activity by the adding of 1 mM MnCl2. T. lettinga ADH was cloned and overproduced in a mesophilic heterologous expression system, and the recombinant enzyme was characterized. It will be helpful to understand more about the physiological role of group 3 alcohol dehydrogenase.[...] Read More.
Keywords: Group 3 ADH, bioinformatic analysis, recombinant expression, thermophilic, catalytic properties.
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文章
A.  K. Al-Ghamdi, S. M. A. Abdelmalek* A. M. Ashshi, H. Faidah, H. Shukri  and A. A. Jiman-Fatani
Abstract: This study aims at investigating the status of bacterial contamination of four daily used objects, computer keyboards, computer mice, elevator buttons and shopping carts handles. A total of 400 samples were collected from 4 different objects; 100 from each. Samples were collected from different places (offices, internet cafes, homes, buildings and supermarkets) in the city of Jeddah, Saudi Arabia. 95.5% of the total samples collected were contaminated with mixed bacterial growth. Coagulase-negative staphylococci dominated the isolates. The second most common bacterial growth in all specimens was Gram-positive bacilli. Potential pathogens isolated from all specimens were: Staphylococcus aureus, Pseudomonas spp. and Gram negative bacilli. Results indicate that internet café computer keyboards and mice showed 100% contamination in comparison with other objects. The presence of pathogenic and commensal bacteria on the four objects indicates that they might act as environmental vehicles for the transmission of potentially pathogenic bacteria.[...] Read More.
Keywords: Bacterial contamination, computers, public surfaces.
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文章
Efuntoye M. O.*, Bakare A. A. and Sowunmi A. A.
Abstract: A total of 34 isolates of bacteria, 20 Staphylococus aureus and 14 Clostridium perfringens from leachate samples, were investigated for virulence factors and antibiotic resistance. Majority (>70%) of the isolates produced enterotoxins. Many of the S. aureus isolates tested positive for deoxyribonuclease, haemolysins and slime production. Staphylococcal enterotoxin A (SEA) was the predominant enterotoxin produced by the S. aureus. None of the S. aureus was resistant to ciprofloxacin, novobiocin and vancomycin. Six isolates were resistant to methicillin and majority of them were resistant to penicillin, ampicillin and bacitracin. Eleven (78.6%) of the C. perfringens isolates produced enterotoxin and were also beta haemolytic. Except for one strain each of C. perfringens which were resistant to penicillin and ampicillin-sulbaltam respectively, all others were susceptible to the antibiotics tested. The presence of several of the virulence traits investigated and resistance to commonly used antibiotics in many of the S. aureus and C. perfringens tested raises concern about their dissemination through leachate to the environment. The accumulation of leachate and possible contamination of surface and groundwater sources also points out its potential risk for public health. There is need for some measures to properly manage waste and consequently reduce surface and groundwater contamination through leachate percolation.[...] Read More.
Keywords: Virulence factor, landfill leachate, antibiotic resistance, Staphylococcus aureus, Clostridium perfringens, health impact.
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Shahzad Akbar Khan*, Tarique Hussain, Muhammad Akhtar Qureshi, Gulzar Ahmed, Sarfaraz Ali Fazlani, Ijaz Ahmed and Farhan Anwar Khan
Abstract: Indirect Haemaglutination test is a reliable quantitative serological test for measuring antibodies against angara disease. The etiological agent contained in the liver of affected chick did not directly haemaglutinate erythrocyte of chickens. The antibody titre measured through IHA varied from 1:8-1: 128, in the sera (samples) of experimentally infected chickens at days 7, 14 and 21 post vaccination.[...] Read More.
Keywords: Haemagglutination, titre, sera, angara disease.
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文章
Ivana D. Radojević*, Milan S. Stanković, Olgica D. Stefanović, Marina D. Topuzović, Ljiljana R. Čomić and  Aleksandar M. Ostojić
Abstract: In vitro antifungal activity of methanol, acetone and ethyl-acetate extracts from Equisetum telmateia Ehrh., Allium flavum L., Sedum acre L., Sideritis montana L., Marubium peregrinum L. and Xeranthemum anuum L. grown in Serbia, were investigated by microdilution method. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) have been determined. Testing was conducted against four Aspergillus species - A. flavus, A. fumigatus, A. niger and A. restrictus. All statistical analyses were performed using SPSS package. The tested extracts showed significant antifungal activity against A. restrictus and moderate activity against other Aspergillus spp. The best results showed ethyl acetate extract of S. montana, X. anuum and S. acre.[...] Read More.
Keywords: Antifungal activity, plant extracts, Aspergillus spp.
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文章
Salama M. Abdel Hafez, Khaled A. Abd El-Razik*, Hany M. Hassan and Ibrahim Gad
Abstract: Brucellosis is an important disease affecting mainly sheep and goats. Diagnosis based on isolation of Brucella organisms from the suspected animals is the golden standard but has a limited sensitivity, expensive and unpractical to apply on a large scale in control campaigns. Accordingly, the indirect diagnosis of disease based on serological tests is the method of choice in the eradication programs. In this study, a single step polymerase chain reaction (PCR) was used to diagnose brucellosis using sheep whole blood and compared its sensitivity and specificity against some of the most commonly used serological techniques and modified ones. Three hundred apparently healthy ewes were randomly chosen from different governorates of Egypt. Sera were tested against Rose Bengal test (RBT), Serum Agglutination test (SAT), ELISA using both the whole Brucella antigen (W-ELISA) and the periplasmic protein antigen (P-ELISA). Results showed that 39% of the blood samples were positive to the PCR test, Meanwhile 29.3, 27.0, 28.7 and 28.3% were positive to the previous serological tests respectively. We recommend the use of this blood PCR assay for accurate diagnosis of ovine brucellosis especially in the early stage of infection, which is difficult to achieve by the applied serological tests.[...] Read More.
Keywords: Ovine brucellosis, Blood PCR, RBT, SAT, ELISA.
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文章
Imran Khan, Puja Gupta and Jyoti Vakhlu*
Abstract: An extra-cellular thermo-alkaliphillic protease producing Bacillus was isolated from the soil and identified to be Bacillus tequilensis MTCC 9585 by microscopic, colony morphology, biochemical and 16S ribotyping. B. tequilensis MTCC 9585 produces protease up to 21 h of growth but interestingly 90% of the protease production occurred, just after 6 h of growth. The organism grew as well as and produced enzyme at wide pH (5 to 12) and temperature range (4, 25, 37 and 50°C), though optimum temperature and pH for the growth of the Bacillus were 37°C and pH 7.0. Optimum pH for enzyme activity coincided with optimum pH for enzyme production at pH 10. Optimum temperature for enzyme activity was 60°C and the enzyme stayed stable over the period of 270 days (9 months) at 10°C. Metal ions like Ca2+, Mg2+, K+ increased the enzyme activity whereas Cu2+, Zn 2+ inhibit the activity slightly. Wash performance and stain removal efficiency increased when partially purified enzyme was used in conjunction with selected detergent. B. tequilensis can be a potential candidate for use in detergent industry because: of couple of reasons such as (i) 90% of the protease is produced only after 6 h of growth (economically viable), (ii) it’s activity in wide pH and temperature range (iii) it’s stability over the period of 9 months at 10°C indicating good shelf life and (iv) detergent compatibility.[...] Read More.
Keywords: Bacillus tequilensis, alkaline protease, pH, temperature, detergent compatibility.
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文章
Yong-Yu Zhang*, Zheng-hao Chen, Zhuo Zhen and Jun Yang
Abstract: Eddy pumping is a process by which mesoscale eddies induce isopycnal displacements that lift nutrient-replete waters into the euphotic zone, driving a set of biogeochemical processes in the ocean. To investigate the potential effect of physical processes on the microbial community functions, the microbial community metaproteomic profiles were determined in a cold-core cyclonic eddy in the South China Sea (SCS). The significant differences of metaproteomic patterns accurately predicted their distinct functional responses to environmental changes caused by the mesoscale cyclonic eddy perturbations. From the protein gel profiles, 11 proteins were successfully identified by MALDI TOF MS/MS, including nitrogen regulatory proteins, ribosomal proteins and substrate transport proteins, etc, which implied the metabolic responses of the microbial populations to the nutrients change within the cyclonic eddies. These results highlight the potential of metaproteomics for studying complex microbial consortium in the ocean and contributed to our understanding of the biological consequences of a mesoscale cyclonic eddy in the SCS.[...] Read More.
Keywords: Cyclonic eddy, metaproteomics, microbial community.
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