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Lu S.-Y.,Jilin University | Lin C.,Jilin University | Li Y.-S.,Jilin University | Zhou Y.,Jilin University | And 6 more authors.
Analytical Biochemistry | Year: 2012

A lateral flow immunochromatographic (LFIC) test strip based on a colloidal gold-monoclonal antibody (McAb) conjugate was developed for on-site rapid detection of okadaic acid (OA) in shellfish. It applies a competitive format using an immobilized toxin conjugate and free toxin present in samples. The McAb against OA was conjugated with 20-nm colloidal gold as detector reagent. The toxin in the sample competed with the immobilized toxin to bind to the gold conjugated with McAb. The colloidal gold/McAb/toxin mobile complex was not captured by OA-bovine serum albumin (BSA) on the test line, but it was captured by goat anti-mouse immunoglobulin G (IgG) on the control line. The color density of the test line correlated with the concentration of toxin in the range of 10-50 ng ml -1. The qualitative detection limit of 150 μg kg -1 sample was close to the European Union (EU) regulatory limit (160 μg kg -1). Therefore, these strips were able to directly and qualitatively estimate the consuming safety of shellfish. They require no equipment because of available visual results, and they screened numerous samples within 10 min. The results were further confirmed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). As a food safety screening tool, the test strips are convenient and useful to rapidly on-site test the presence of OA in shellfish products. © 2012 Elsevier Inc. All rights reserved. Source

Zhou Z.-S.,Chinese Academy of Agricultural Sciences | Rasmann S.,University of California at Irvine | Li M.,Fujian Entry exit Inspection and Quarantine Bureau | Guo J.-Y.,Chinese Academy of Agricultural Sciences | And 2 more authors.
PLoS ONE | Year: 2013

The leaf beetle, Ophraella communa, has been introduced to control the spread of the common ragweed, Ambrosia artemisiifolia, in China. We hypothesized that the beetle, to be able to track host-range expansion into colder climates, can phenotypically adapt to cold temperatures across generations. Therefore, we questioned whether parental experience of colder temperatures increases cold tolerance of the progeny. Specifically, we studied the demography, including development, fecundity, and survival, as well as physiological traits, including supercooling point (SCP), water content, and glycerol content of O. communa progeny whose parents were maintained at different temperature regimes. Overall, the entire immature stage decreased survival of about 0.2%-4.2% when parents experienced cold temperatures compared to control individuals obtained from parents raised at room temperature. However, intrinsic capacity for increase (r), net reproductive rate (R0) and finite rate of increase (λ) of progeny O. communa were maximum when parents experienced cold temperatures. Glycerol contents of both female and male in progeny was significantly higher when maternal and paternal adults were cold acclimated as compared to other treatments. This resulted in the supercooling point of the progeny adults being significantly lower compared to beetles emerging from parents that experienced room temperatures. These results suggest that cold hardiness of O. communa can be promoted by cold acclimation in previous generation, and it might counter-balance reduced survival in the next generation, especially when insects are tracking their host-plants into colder climates. © 2013 Zhou et al. Source

Wei-chuan Z.,Fujian Entry exit Inspection and Quarantine Bureau | Gui-ming Z.,Shenzhen Entry Exit Inspection and Quarantine Bureau
Journal of Plant Pathology | Year: 2010

Tilletia indica Mitra, the cause of Karnal bunt of wheat, is an important quarantine disease around the world. The Humid Thermal Index (HTI) model, and the bioclimate zoning map of wheat in China are based on critical values of key climatic factors during the susceptible period (heading and anthesis of wheat). We have calculated improvements to the HTI value for both early and late sown wheat varieties, with 21 days as a cycle (heading and anthesis period) and 1 day as a slip statistical unit. A GeoPhytopathology Model (GPMTI) for T. indica was built using a Microsoft Access Database, Map- Info MapX and Visual Basic, and was used to predict the potential geographic distribution areas of T. indica using climate data collected in the past 30 years from 670 meteorological stations. The results showed that the pathogen could establish itself in 60% of sites in China (nearly 4,580,000 km2), and this region can be divided into four areas: safe areas (HTI value for all periods unsuitable for disease development), low risk areas (HTI value for less than one-third of the periods suitable for disease development), risk areas (HTI value for between one-third and two-thirds of the periods suitable for disease development) and high risk areas (HTI value for more than two-thirds of the periods suitable for disease development). The risk areas and high risk areas were about 3,210,000 km2. Source

Qiu Y.,Fujian Entry exit Inspection and Quarantine Bureau
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui | Year: 2012

A liquid chromatography-tandem mass spectrometry method was established for the determination of virginiamycin M1 and S1 residues in livestock and poultry products. The sample was extracted by methanol-acetonitrile solution (1:1, v/v). The supernatant was diluted with 0.01 mol/L ammonium dihydrogen phosphate solution, then purified and concentrated on an Oasis HLB cartridge. The separation of virginiamycin M1 and S1 was performed on a Luna C18 column with the mobile phases acetonitrile and 5 mmol/L ammonium acetate aqueous solution (containing 0.1% (v/v) formic acid) in a gradient elution mode. The identification and quantification of the drugs were carried out by positive electrospray ionization (ESI + ) in the multiple reaction monitoring (MRM) mode using external standard method. The calibration curves showed good linearity in the range of 0.15-10.0 microg/L with correlation coefficients (r2) above 0. 999. The limits of quantities (LOQs) were both 0.25 microg/kg. The average recoveries of the two drugs spiked at 0.25, 0.5 and 2.5 microg/kg levels in different matrices were between 71.2% and 98.4%, and the relative standard deviations (RSDs) were between 3.6% and 15.4%. The method is simple, rapid, sensitive and accurate. It is suitable for the confirmation and quantification of virginiamycin M1 and S1 residues in livestock and poultry products. Source

Yang F.,Fuzhou University | Liu Z.,Fujian Entry exit Inspection and Quarantine Bureau | Lin Y.,Fujian Entry exit Inspection and Quarantine Bureau | Chen J.,Fujian Entry exit Inspection and Quarantine Bureau | And 2 more authors.
Food Analytical Methods | Year: 2012

β-Agonists have been abused as the growth-promoting agent in food-producing animals over 20 years. The proof of using illegal drugs in food, which is necessary for a regulatory action, usually requires a high degree of specificity and sensitivity. This paper reported an ultra-high performance liquid chromatography (UHPLC)-ESI/MS/MS method for the confirmation of multi-residues of the 13 β-agonist compounds in milk. A wide range of analytes related to β-agonists (brombuterol, cimaterol, clenbuterol, clenpenterol, clorprenaline, hydroxymethylclenbuterol, isoxsuprine, mabuterol, ractopamine, ritodrine, salbutamol, terbutaline, tulobuterol) with similar chemical structures was investigated in order to demonstrate the applicability of our method. This method consists of a two-step extraction and a MCX SPE cleanup. The final extract was separated by UHPLC within 5 min and then injected in an electrospray ionization mass spectrometry for the determination. Using clenbuterol-D9, salbutamol-D3, and ractopamine-D5 as internal standards, and accomplishing with the matrix matched calibration curves to compensate for the matrix effects, the quantitative data showed good linear response within the concentration ranges studied. The detection limits (CCα) and detection capabilities (CCβ) of the analytes were found in the range of 0.01-0.16 μg/L and 0.03-0.21 μg/L, respectively. Recoveries of the compounds were found from 82.5% to 101% at the spiked level of 0.05-2.5 μg/L, and the relative standard deviation was within the range of 7.17% and 16.4%. Furthermore, an inter-laboratory study among eight laboratories was conducted to further validate the method, and the results were found satisfactory. © 2011 Springer Science+Business Media, LLC. Source

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