MOSP - Macao Scientific Publishers

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Effect of salinity on free living - diazotroph and total bacterial populations of two saline soils

Azam Moradi, Arezoo Tahmourespour*, Mehran Hoodaji and Farhad Khorsandi

Abstract: Salinization of soil is a serious problem and is increasing steadily in many parts of the world. Recently, soil biotechnology application can improve the potential of saline soils land use in agriculture. The aim of this research was determining the salinity effect on free-living diazotroph and total bacterial populations in two saline soils. Soil samples with salinity of 35 and 70 dS/m selected. The heterotrophic and free-living diazotrophic bacterial populations were counted on nutrient agar and free-nitrogen medium. The salinity effect on population of each soil was determined on same media supplemented with 0.44 and 1.02 M NaCl (equal with EC 35 and 70 dS/m of each soil). The results showed that, the free- living diazotrophic and total heterotrophic bacterial populations in soil sample 1 was significantly (P < 0.05) more than soil sample 2. Also the heterotrophic and diazotrophic bacterial population in each soil sample were significantly less in the presence of salt. Soil salinity is a stress factor relating to microbial selection process and can reduce bacterial diversity and control microbial abundance, composition and functions. Use of soil halotolerant or halophyl bacterial strains which can either fix atmospheric nitrogen will be environmentally begin approach for nutrient management and ecosystem function for saline soils.[...] Read More.

Keywords: Salinity, bacterial population, diazotrophic, heterotrophic.

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Isolation and identification of endophytic bacterium W4 against tomato Botrytis cinerea and antagonistic activity stability

Cong-Jun Yang, Xin-Gang Zhang, Guan-Ying Shi, Hao-Yu Zhao, Long Chen, Ke Tao,* and Tai-Ping Hou,*

Abstract: Of the 72 endophytic bacteria isolated from healthy tomato stems and leaves from field-grown plants, the strain W4 gave strongly inhibitory effect on Botrytis cinerea Pers, with the inhibition rate 78% in dual culture assay and 100% using fermentation filtrate diluted 20 times. Based on morphological, physiological and biochemical properties, 16S rDNA gene sequences and Biolog system analysis, the isolate W4 was identified and named as Brevibacillus brevis W4. The activity determination demonstrated that the antagonistic effect of W4 fermentation filtrate on B. cinerea was fairly stable to temperature, pH, ultraviolet light. Only heated at 90°C for 30 min or at 100°C or above for 10 min, the inhibitory effect was significantly reduced. The inhibitory rate remained above 90% at pH 2-11 and above 95% under ultraviolet light radiation for 5-240 min. These stability characteristics of antagonistic activity were conducive to future applications in the field.[...] Read More.

Keywords: Botrytis cinerea, Brevibacillus brevis W4, endophytic bacteria, antagonistic activity.

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Antibiotic resistance in Escherichia coli strains isolated from water springs in Al-Ahsa Region

Abdullah M. Alzahrani and Youssuf A. Gherbawy,*

Abstract: In Saudi Arabia, water resources are largely limited to groundwater, which is used both for drinking and agriculture. There is no surface water except for a few oases and no permanent streams. The contamination of this source possibly through wastewater, agriculture activities and wild birds as well as amphibians and reptiles that have access to wells and springs. Twenty six strains of Escherichia coli, isolated from water springs in Al-Ahsa Region of Saudi Arabia were analyzed for their antimicrobial susceptibility. Fifteen strains, representing 57.74% of the total twenty six strains, showed multidrug resistance phenotypes. RAPD -PCR with two random primers produced different DNA fingerprinting profiles with varied number of bands. The dendrogram obtained from the RAPD-PCR results discriminated the isolates into 26 single isolates and 3 clusters at the level of 40% similarity.[...] Read More.

Keywords: Escherichia coli, antibiotic resistance, water springs, RAPD-PCR.

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Actinopolyspora egyptensis sp. nov., a new halophilic actinomycete

Wael N. Hozzein,* and Michael Goodfellow

Abstract: A halophilic actinomycete, designated HT371T, was isolated from a soil sample collected from the shore of the salty Lake Qaroun, Egypt, and was the subject of a polyphasic study. Analysis of 16S rRNA indicated that the isolate belonged to the genus Actinopolyspora and constituted a separate clade in the Actinopolyspora 16S rRNA gene tree with similarity values of 96.5 and 96.2% with Actinopolyspora halophila DSM43834T and Actinopolyspora mortivallis DSM44261T, respectively. Isolate HT371T had chemotaxonomic and morphological properties consistent with its classification in the genus Actinopolyspora and could grow on agar plates at NaCl concentrations of up to 25% (w/v). The isolate was readily differentiated from the type strains of genus Actinopolyspora using a range of phenotypic characters. On the basis of polyphasic evidence, the strain HT371T represents a novel species for which the name Actinopolyspora egyptensis sp. nov. is proposed. The type strain is HT371T (=CGMCC 4.2041T).[...] Read More.

Keywords: Actinopolyspora egyptensis sp. nov., halophilic isolate, polyphasic taxonomy.

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-lactam antibiotic resistance in Escherichia coli commensal faecal flora of healthy population in Taif, Saudi Arabia

Eman Mohammed Halawani

Abstract: One hundred and twenty faecal sample of commensal Escherichia coli strains were collected from different healthy persons and tested for their susceptibility to 12 -lactam antibiotics by disc diffusion and minimum inhibitory concentration methods. Colonization with strains resistant to ampicillin (Amp), amoxicillin, carbenicillin and peperacillin was detected in 36.7% of the tested isolates. Resistance patterns to 3-6 -lactams was observed in 91.7% of the tested E. coli isolates. Transfer of Amp resistance marker by conjugation was usually associated with Strepomycin (Stm) and sulfonamise (Sul) in 100% of tested isoletes and with chloramphenicol (Clm) and tetracycline (Tet) in 63.3 and 45.6% of the isolates, respectively. This suggests that resistance markers to Amp, Stm, Sul, Tet and Clm existed as cossets on cojugative plasmids. Therefore, resistance to these antibiotics could rapidly disseminate and persist in the Saudi Society. All Amp resistant isolates produced one or two types of -lactamases with molecular weights of 28.9 and 28.8 KDa, which indicated TEM-1 and SHV-1. Both types of - lactamases are known to be plasmid-mediated in enteric bacterial species and are common in E. coli commensal faecal flora. Extended-spectrum -lactamases (ESBLs) were not detected in any of the tested strains and therefore, these types of -lactamases are uncommon in commensal E. coli in citizens of Taif. Measures should be taken to prevent the misuse of -lactams and the spread of antibiotic resistance in Saudi Society.[...] Read More.

Keywords: Antibiotic resistance, -lactams, -lactamases, commensal Escherichia coli.

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Molecular characterization of antigens extracted from hydatid cysts of human and other intermediate hosts

Mohammed M. A. Al-Fayadh, Maani N. Al-Shemari and Ihsan E. Al-Saimary*

Abstract: This research includes a study of hydatid cysts Echinococcus granulosus (larval stage on the molecular level, where 7 samples of hydatid cysts were collected from parasite intermediate hosts " Human (liver, spleen, lung) and liver of sheep, goat, cattle and buffaloes”. DNA was extracted from germinal layer cells of hydatid cysts which were isolated shortly or preserved for various periods in 70% ethanol. Genetic analysis of isolated DNA from hydatid cysts collected from human and animals was done by polymerase chain reaction (PCR) to determine genetic variation depending on random amplified polymorphic DNA. In the present study 10 primers have been used, during which the genetic variations were revealed among isolated (extracted DNA) of hydatid cysts which was collected from human and other intermediate hosts except Cows and Buffaloes. The current results of this study have shown the following: 1 - It was found one primer (OPA – 01) was able to diagnose sample numbered 1 which represent the isolated DNA of liver hydatid cyst which was obtained from human at age group 10– 20 years old. 2 - The ability of primer OPC – 10 to determine fingerprinting of DNA sample of Sheep liver hydatid cyst. 3 - The ability of primer OPC – 05 to determine fingerprinting of DNA sample of human spleen hydatid cyst which was obtained from human at age group 30 – 40 years old. 4 - The ability of primer OPE – 07 to determine fingerprinting of DNA sample of goat liver hydatid cyst. 5 – Amplification process to the DNA samples which extracted from cows and buffaloes liver hydatid cysts was not completed by using all 10 primers.[...] Read More.

Keywords: Echinococcus granulosus, molecular, antigens, human.

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Identification of clusters in tissue samples in gene expression data with Principal Component Analysis based on relative variance matrix

Uzma Nawaz* and Asghar Ali

Abstract: Principal Component Analysis (PCA) has been in use as a preprocessing step to clustering for long. We have focused on the clustering of tissue samples in gene expression data. Different clustering techniques and algorithm are available in literature on gene expression data but with the existing ambiguity on the number of clusters, apart from relying on biologically known groups. A consensus is needed to reach on the number of clusters in the wide variety of existing clustering techniques based on different similarity or dissimilarity metrics. The conventional usage of PCA for clustering is either by forcing the unit variance to each variable or the high magnitude of variance of an individual variable is allowed to dominate the entire results of PCA. We propose the use of relative variance covariance method in PCA, so as to give due consideration to the joint and individual variances in the dataset and identify clusters with principal component loadings. We emphasize empirically that the proposed approach of PCA is conclusively more informative than the available approaches to identify cluster structure in tissue samples (sample expression profiles). Clusters formed are valid with the existing results on the data set under study and with valid biological background.[...] Read More.

Keywords: Clustering methods, gene expression analysis, principal component analysis, the relative variance covariance matrix, principal component loadings.

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Pathogens change in spontaneous bacterial peritonitis patients with cirrhosis

Yanzi Gou*, Fangxin Zhang, Zhenbin Liang, Xuefan Bai, Lei Pan, Wei Wang, Bo Liu, Jiuping Wang and Dingcheng Wang

Abstract: The aim of this study was to determine the distribution of clinical microorganisms isolated from spontaneous bacterial peritonitis patients. Ascitic fluid was collected from these patients and cultured for pathogens. The patients were placed into three groups, Group A (01/1996 to 12/2000), B (01/2001 to 12/2005) and C (01/2006 to 06/2010) and the clinical data were compared among these groups. There was a significant difference in the ratio of pathogens (Gram- positive bacteria/ isolated pathogens, Gram-negative bacteria/ isolated pathogens) between groups A and C (P < 0.001). Spontaneous bacterial peritonitis patients with Gram-positive bacteria used significantly more antibiotics within 30 days compared to those with Gram-negative bacteria (P < 0.001) . In recent years, the types of isolated pathogens have significantly changed in Northern China. Such changes have also been observed in other countries and have been attributed to long-term antibiotic therapy and invasive procedures. Changes in the epidemiology of pathogens that cause spontaneous bacterial peritonitis must be monitored for optimal treatment.[...] Read More.

Keywords: Pathogens, gram-positive bacteria, spontaneous bacterial peritonitis, cirrhotic patients.

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A magnetic microparticle-based immunoassay for hepatitis C virus NS3 antigen

Full Length Research Paper

Abstract: In order to detect Hepatitis C virus NS3 antigen (HCAg-NS3) in human serum, we developed a magnetic microparticle (MMP) based immunoassay by using biotin-streptavidin amplification, MMP in combination with immunoassay. Results showed that the HCV NS3 monoclonal antibody had a high immobility rate (87.1%) on the surface of MMPs; the assay procedure required smaller volumes of reagents (only 20 l of immune magnetic bead); the detection could be completed within 30 min; this method could detect 10 pg/ml HCAg-NS3 (sensitivity: 5.2 pg/ml) and had favorable stability; the mean coefficient of variances (CVs) of intra-assay and inter-assay were 5.35 and 7.15%, respectively. The results of this method were also related to those in HCV RNA detection with a linear correlation coefficient of 0.570 (P < 0.01). These findings demonstrate this assay which has high specificity, sensitivity, precision and stability may be promising in clinical application.[...] Read More.

Keywords: Hepatitis C virus NS3 antigen, magnetic microparticle, biotin-streptavidin sytem (ABS), magnetic immunoassay.

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Immunomodulatory effects of novel bifidobacterium and lactobacillus strains on murine macrophage cells

Jun Zhu, Liang Zhao, Huiyuan Guo, Lu Jiang, and Fazheng Ren,*

Abstract: The principle purpose of this study was to investigate the immunomodulatory ability of three microbial strains isolated from Bama County centenarians in activating macrophages, and to characterize the effective component of these strains. A murine macrophage cell line, RAW264.7, was cultured in presence of intact bacterial cells, bacterial cell wall (CW) or cell free extract (CFE) . NO, IL-6, TNF-production and phagocytic activity of co-cultured macrophages were tested. Bifidobacterium adolescentis BBMN23, Bifidobacterium longum BBMN68 and Lactobacillus saliva Ren were demonstrated to enhance the activities of macrophages by increasing the phagocytic activity and NO, IL-6, TNF- production. The immunomodulatory activities of these microbial strains are mainly due to the CW fraction, although their CFE were also effective. The results of this study indicated that specific substrains of bifidobacterium and lactobacillus from guts of healthy centenarians (Bama County, China) may be of immunomodulatory value, and thus may have the potential to be used as probiotics.[...] Read More.

Keywords: Bifidobacterium, lactobacillus; RAW 264.7 cells, immunomodulatory activities, bacterial fractions.

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