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Chen W.-M.,National Taiwan Ocean University | Chen W.-M.,Toxic Substances Research Institute | Chen G.-H.,Providence University | Jiang S.-T.,National Taiwan Ocean University | Jiang S.-T.,Providence University
Journal of Marine Science and Technology (Taiwan) | Year: 2012

(rEC-H) was expressed and characterized. After Ni affinity chromatography, the recovery, purification-fold and specific activity of rEC-H were 88.8%, 13.4 and 142.1 U/mg, respectively. The purified rEC-H had optimal pH and temperature at pH 7.5 and 60°C, respectively and was stable at pH 4.0-9.0 and <50°C. It was activated by Ca 2+, Sr 2+, Ba 2+, Co 2+ and β-mercaptoethanol, but highly inhibited by Cu 2+, Hg 2+ and SDS. The thiol group may play an important role on rEC-H and rEC-H may easily be destructed when hydrophobic interaction is disrupted by sodium dodecyl sulfate. The molecular mass was lower than that of expected due to cleavage at 2 specific sites, 33Ala- 34Asp and 472Glu- 473Leu within rEC-H, suggesting the fragmentation of rEC-H occurred during expression.

Lo C.-C.,Toxic Substances Research Institute
Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes | Year: 2010

According to guidelines for the approval of pesticides, information about effects of pesticides on soil microorganisms and soil fertility are required, but the relationships of different structures of pesticides on the growth of various groups of soil microorganisms are not easily predicted. Some pesticides stimulate the growth of microorganisms, but other pesticides have depressive effects or no effects on microorganisms. For examples, carbofuran stimulated the population of Azospirillum and other anaerobic nitrogen fixers in flooded and non-flooded soil, but butachlor reduced the population of Azospirillum and aerobic nitrogen fixers in non-flooded soil. Diuron and chlorotoluron showed no difference between treated and nontreated soil, and linuron showed a strong difference. Phosphorus(P)-contains herbicides glyphosate and insecticide methamidophos stimulated soil microbial growth, but other P-containing insecticide fenamiphos was detrimental to nitrification bacteria. Therefore, the following review presents some data of research carried out during the last 20 years. The effects of twenty-one pesticides on the soil microorganisms associated with nutrient and cycling processes are presented in section 1, and the applications of denaturing gradient gel electrophoresis (DGGE) for studying microbial diversity are discussed in section 2. © Taylor & Francis Group, LLC.

Ceshing-Sheu,Chaoyang University of Technology | Chen S.-C.,Toxic Substances Research Institute | Lo C.-C.,Toxic Substances Research Institute
Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes | Year: 2010

A high performance liquid chromatographic (HPLC) analysis method with an ultraviolet (UV) detector and an Aqua C18 (250 × 4.6 mm, Phenomenex) column were applied to analyze the antibiotic fungicide kasugamycin in water. An aromatic sulfonic acid spe column (Backerbond, J. T. Backer) was used to remove the interfering materials from irrigation water. A good linear relation existed between the concentration of the fungicide and the peak area, and correlation coefficient of linearity from 0.1 to 10.2 μg/mL was 0.998. The accuracies expressed as the recoveries of kasugamycin from irrigation water ranged from 112.2 to 111.7 %. The precisions expressed as relative standard deviations (RSD) were found to be below 7.0 %. The quantitative detection limit (LOQ) of kasugamycin in irrigation water was set at 2.2 μg/mL which was 2-times higher than the method detection limit (MDL) 1.03 μg/mL. Electrospray ionization-mass (ESI-MS) and fast-atom bombardment-mass (FAB-MS) were applied to compare the ability of identifying the component of the eluent peak from HPLC, and the result indicated that electrospray ionization-mass (ESI-MS) was more sensitive than fast-atom bombardment-mass (FAB-MS) in the detection of kasugamycin. There was no kasugamycin residue detected in irrigation water samples collected from paddyfields at Wufong, indicated that the residues of kasugamycin in water were less than 2.2 μg/mL, and the risk of water contamination was very low. © Taylor & Francis Group, LLC.

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