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Du Z.,Shandong University | Wang J.,Weihai Entry Exit Inspection and Quarantine Bureau | Yang L.,Weihai Entry Exit Inspection and Quarantine Bureau | Chen G.,Shandong University
Acta Oceanologica Sinica | Year: 2011

A total of 117 agar-decomposing cultures were isolated from coastal seawater around Qingdao, China. The phenotypic and agarolytic features of an agarolytic isolate, QM38, were investigated. The strain was gram negative, strictly aerobic, curved rod and polar flagellum. On the basis of several phenotypic characters, biochemical and morphological characters and phylogenetic analysis of the gene coding for the 16S rRNA, the strain was identified as Agarivorans albus strain QM38. This strain can liquefy the agar on the solid agar plate. An excellular agarase activity was determined in liquid culture. The enzyme exhibited maximal activity at 40°C, pH 7.6. Its activity was greatly affected by different concentrations of agarose. The highest activity 32 U/ml was achieved in the culture supernatant. The hydrolytic product was analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE). After complete hydrolysis of agarose, a series of agaro-oligosaccharides were produced. The main products of the enzymes were oligosaccharides in the degree of polymerization (DP) of 2, 4, 6 and 8. Three genes agaD01, agaD02 and agaD03, encoding β-agarases, had been cloned from genomic DNA of Agarivorans albus strain QM38. The open reading frame of agaD01, consisted of 2 988 bp, and shared 95.5%-98.9% identity to the β-agarase genes of some strains of Vibrio and Agarivorans. Gene agaD02 comprised 2 868 bp and encoded a 955-amino-acid protein. It showed 97.4% and 98.7% identity to the β-agarase genes of strain Vibrio sp. PO-303 and strain Vibrio sp. JT0107, respectively. Only partial sequence of agaD03 gene has been cloned. It showed 96.5% identity to β-agarase gene (agaB) of Pseudoalteromonas sp. CY24, and shared 96.8% identity to β-agarase-c gene of Vibrio sp. PO-303. © The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg 2011. Source

Zhang J.,Beijing Entry Exit Inspection and Quarantine Bureau | Li Z.,Weihai Entry Exit Inspection and Quarantine Bureau | Zhang H.,Beijing Entry Exit Inspection and Quarantine Bureau | Wang J.,Weihai Entry Exit Inspection and Quarantine Bureau | And 2 more authors.
Journal of Microbiological Methods | Year: 2013

F0F1-ATPase within chromatophore was constructed as a molecular motor biosensor through ε-subunit antibody-biotin-streptavidin-biotin-AC5-Sulfo-Osu system. Based on probe-DNA specific binding, DNA of several foodborne pathogens Listeria monocytogenes, Salmonella typhimurium, Vibrio parahaemolyticus and Vibrio cholerae was specifically captured by F0F1-ATPase molecular motor biosensors. Loads of DNA decreased the rotation rate of F0F1-ATPase, and led to the decrease of ATP synthesis. The detection of pathogens based on proton flux change driven by ATP-synthesis of F0F1-ATPase, which was indicated by F-DHPE, was monitored by a fluorescence spectrometer. The results demonstrate that the F0F1-ATPase molecular motor biosensor can specifically detect bacterial DNA at low concentration level, and will be a convenient, quick, and promising tool for detecting pathogens. © 2013 Elsevier B.V. Source

Zhang Z.,Beijing Inspection and Quarantine Testing Center | Yan H.,Beijing Inspection and Quarantine Testing Center | Cui F.,Beijing Inspection and Quarantine Testing Center | Yun H.,Beijing Inspection and Quarantine Testing Center | And 5 more authors.
Food Analytical Methods | Year: 2015

The objective of the present study is to develop and optimize a simple, high-throughput method for determining 14 β-agonists (i.e., banbuterol, brombuterol, cimaterol, cimbuterol, clenbuterol, clenpeterol, clorpenaline, isoxsuprine, mabuterol, mapenterol, ractopamine, salbutamol, terbutaline, and tulobuterol) and two β-blockers (propranolol and penbutolol) in porcine muscle. The samples were pretreated by a modified quick, easy, cheap, efficient, rugged, and safe (QuEChERS) method, and analysis was carried out in a reversed phase HSS T3 C18 column using gradients of acetonitrile and 5 mmol L−1 ammonium acetate (0.1 % formic acid) solution for elution. Ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-LTQ Orbitrap MS, resolution 60,000) was used for qualification and quantification of the 16 target compounds. Under optimized conditions, the limits of detection and quantification obtained ranged from 0.17 to 1.67 μg kg−1 and from 0.56 to 5.00 μg kg−1, respectively. Recoveries for spiking levels of 5.0, 10.0, and 20.0 μg kg−1 ranged from 62.4 to 121.9 %, from 60.4 to 104.3 %, and from 66.5 to 121.3 %, respectively. The relative standard deviations obtained were lower than 20 % for all spiking levels assayed. The proposed method was applied successfully in sample analysis, and satisfactory results were obtained. © 2015 Springer Science+Business Media New York Source

Yang L.J.,Weihai Entry Exit Inspection and Quarantine Bureau | Wang J.,Weihai Entry Exit Inspection and Quarantine Bureau | Li Z.J.,Weihai Entry Exit Inspection and Quarantine Bureau | Song X.H.,Weihai Entry Exit Inspection and Quarantine Bureau | And 2 more authors.
Advanced Materials Research | Year: 2014

Fourier transform infrared spectroscopy (FTIR) combined with multivariate statistical analysis was applied to differentiate and identify Shigella sonnei and Escherichia coli O157: H7. FTIR absorption spectra from 4000-600 cm-1 were collected from sampling 10 μL of bacterial suspention. The spectra between 1800 and 900 cm-1 highlighted the most distinctive variations and were the most useful for characterizing the selected microorganisms. Spectra of the two bacteria were noticeably segregated with distinct clustering by principal component analysis (PCA). Further more, another cluster model of hierarchical cluster analysis (HCA) was established and could also gave a good separation between the two bacteria. These results demonstrate that FTIR technology has considerable potential as a rapid, accurate and simple method for differentiating and identifying bacteria. © (2014) Trans Tech Publications, Switzerland. Source

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