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Now showing items 1 - 16 of 69

  • In vivo cardiovascular toxicity induced by acetochlor in zebrafish larvae

    Liu, Hongcui   Chu, Tianyi   Chen, Lili   Gui, Wenjun   Zhu, Guonian  

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  • Determination of Sterigmatocystin in Infant Cereals from Hangzhou, China

    Liu, Shaoying   Fan, Jicai   Huang, Xihui   Jin, Quan   Zhu, Guonian  

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  • Track of fate and primary metabolism of trifloxystrobin in rice paddy ecosystem

    Cao, Mengchao   Li, Shuying   Wang, Quansheng   Wei, Peng   Liu, Yanan   Zhu, Guonian   Wang, Mengcen  

    Trifloxystrobin, a strobilurin fungicide, has beenwidely applied to control fungal diseases in various crops, especially in rice cultivation. However, its residual profile in rice paddy thatwas highly linked to its ecological risk still remains poorly understood. To elucidate the fate and primary metabolismof trifloxystrobin in rice paddy, a simple and efficient analyticalmethod was developed using the DisQuE extraction kit combined with GC-mu ECD and GC-EI-MS/MS analyses. As a result, methodological recoveries of trifloxystrobin fortified in paddywater, soil and rice strawranging from0.005 to 2 mg kg(-1) (mg L-1 forwater) were acquired from87.6% to 109.1% with relative standard deviation (RSD) from 1.9% to 9.5% (n= 5), and the limit of detection (LOD, signal to noise (S/N) = 3) and the limit of quantification (LOQ, S/N = 10) were 6.3 x 10(-4) mg L-1 and 2.09 x 10(-3) mg L-1, respectively, which indicates the favorable accuracy, precision and sensitivity of the method for effective monitoring of the trace amounts of residual trifloxystrobin in the rice paddy. Furthermore, dissipation of residual trifloxystrobin was in accordance with the first-order rate equation, showing the half-lives from 0.7 to 7.5 days, illustrating that trifloxystrobin generally degraded in a rapid rate in the rice paddy. Additionally, trifloxystrobin acid identified as the primary metabolite of trifloxystrobin in the rice paddy via GC-EI-MS/MS analysis was found to be dominantly accumulated in the paddy water and maintained up to 2.41 mg L-1 within 14 days, suggesting that long-termand frequent application of this fungicide may pose a high risk towards aquatic organisms in surrounding aqueous ecosystems through paddy drainage. Taken together, our data serve as a useful tool for monitoring residual trifloxystrobin in rice paddy ecosystem and also provide a basis for in-depth understanding of environmental behavior and ecological risk posed by this fungicide. (C) 2015 Elsevier B.V. All rights reserved.
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  • An Improved Rapid On-Site Immunoassay for Triazophos in Environmental Samples

    Gui, Wenjun   Liang, Chizhou   Guo, Yirong   Zhu, Guonian  

    The suitability of enzyme-linked immunosorbent assay for rapid and on-site determination of triazophos in environmental samples was investigated. The optimized rapid ELISA can be completed in around 10 min at ambient temperature. A rapid sample preparation procedure was developed which can be performed on field site for fresh water and soil samples. The rapid assays can process 40 samples within 1 h including the sample preparation time. It can be concluded that this rapid assay would be a potential, effective method for monitoring triazophos in the environment, especially when quick Judgment regarding low or high contamination is critical.
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  • Thyroid endocrine disruption of azocyclotin to Xenopus laevis during metamorphosis

    Li, Meng   Cao, Chuyan   Li, Shuying   Gui, Wenjun   Zhu, Guonian  

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  • Effects of pyrethroid pesticide cis -bifenthrin on lipogenesis in hepatic cell line

    Xiang, Dandan   Chu, Tianyi   Li, Meng   Wang, Qiangwei   Zhu, Guonian  

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  • Synthesis and Antifungal Activities of Trichodermin Derivatives as Fungicides on Rice

    Xu, Xiaojun   Cheng, Jingli   Zhou, Yong   Zhang, Chulong   Ou, Xiaoming   Su, Weike   Zhao, Jinhao   Zhu, Guonian  

    Twenty new trichodermin derivatives, 2a5, containing alkoxy, acyloxy, and Br groups in 4-, 8-, 9-, 10- and 16-positions were synthesized and characterized. The antifungal activities of the new compounds against rice false smut (Ustilaginoidea virens), rice sheath blight (Rhizoctonia solani), and rice blast (Magnaporthe grisea) were evaluated. The results of bioassays indicated that the antifungal activities were particularly susceptible to changes at 4-, 8-, and 16-positions, but low to changes at 9- and 10-positions. Most of these target compounds exhibited good antifungal activities at the concentration of 50mgl1. Compound 4 (9-formyltrichodermin; EC50 0.80mgl1) with an CHO group at 9-position displayed nearly the same level of antifungal activity against Ustilaginoidea virens as the commercial fungicide prochloraz (EC50 0.82mgl1), while compound 3f ((8R)-8-{[(E)-3-phenylprop-2-enoyl]oxy}trichodermin; EC50 3.58 and 0.74mgl1) with a cinnamyloxy group at C(8) exhibited much higher antifungal activities against Rhizoctonia solani and Magnaporthe grisea than the commercial fungicides prochloraz (EC50 0.96mgl1) and propiconazole (EC50 5.92mgl1), respectively. These data reveal that compounds 3f and 4 possess high antifungal activities and may serve as lead compounds for the development of fungicides in the future.
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  • Degradation properties and identification of metabolites of 6-Cl-PMNI in soil and water

    Wang, Yihu   Sun, Qianqian   Tian, Chunxia   Gui, Wenjun   Zhu, Guonian  

    Highlights • 6-Cl-PMNI is stable in room temperature and neutral media. • Temperature is the main fact which influences the hydrolysis of 6-Cl-PMNI. • The C C olefinic bond reacted with H2O may be the main hydrolytic mechanism. • 6-Cl-PMNI can be readily degraded in soil mainly by microbial action. • The split of C–Cl is proposed as the degradation pathway of 6-Cl-PMNI in soil. Abstract In order to provide the scientific basis for the environmental risk assessment of cycloxaprid and 6-Cl-PMNI (intermediate of cycloxaprid), the degradation properties of 6-Cl-PMNI in aerobic, anaerobic and/or sterile soil, as well as in water with different pH values at different temperature were explored under laboratory conditions using HPLC for its kinetics study and UPLC-MS/MS for the identification of its metabolites/degradation products. Fortification study showed that the recoveries of 71.4–100.5% with the maximum coefficient variation (CV) of 7.47% were obtained. The linear range was 0.1–10 mg/L with the good linearity of R2 = 0.9990. For standard, the method LOD (limit of detection) and LOQ (limit of quantification) was 0.03 mg/L and 0.1 mg/L, respectively. Results demonstrated the good performance of the developed method. Kinetics study indicated that the degradation half-lives (t0.5) in pH 3-pH 10 buffers varied from 111.8 d to 288.8 d at 25 °C but rapidly shortened to 1.6–25.7 d at 70 °C. Good negative linear ships (R2 ≥ 0.8423) between half life and temperature were found. 6-Cl-PMNI could be readily degraded in non-sterile soil (t0.5 0.8–7.5 d) while slowly degraded in sterile soil (t0.5 64.8–91.2 d). Three hydrolytic products and one metabolite of 6-Cl-PMNI in aerobic soil were identified. The C C olefinic bond reacted with H2O by Markovnikov Additive Reaction and the split of C–Cl were mainly proposed as the possible reaction pathway for 6-Cl-PMNI degradation in water and in soil, respectively. Graphical abstract
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  • miRNA-216 and miRNA-499 target cyb561d2 in zebrafish in response to fipronil exposure

    Zhou, Yongyong   Huang, Hannian   Zhang, Kai   Ding, Xianfeng   Jia, Longlue   Yu, Liang   Zhu, Guonian   Guo, Jiangfeng  

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  • Changes in Thyroid Hormone Levels during Zebrafish Development

    Chang, Juhua   Wang, Minghua   Gui, Wenjun   Zhao, Ying   Yu, Liang   Zhu, Guonian  

    The zebrafish (Danio rerio) has been used as a model for the study of endocrine disrupting chemicals. This study set out to determine the profiles of whole-body thyroxine (T4) and 3,5,3'-triiodothyronine (T3) levels during the development of zebrafish from embryo to adult. Enzyme-linked immunoassay was used to analyze whole-body T4 and T3 contents. The results showed that whole-body T4 and T3 levels remained stable during the pre-hatching period (0-3 d) and increased significantly during early development after hatching. The T3 level peaked at 0.28 +/- 0.01 ng g(-1) body weight at 10 days post-fertilization (dpf), and T4 peaked at 0.58 +/- 0.09 ng g(-1) body weight at 21 dpf. Both thyroid hormones subsequently declined during later development. This study establishes a baseline for thyroid hormones in zebrafish, which will be vital for the understanding of thyroid hormone functions and in future studies of thyroid toxicants in this species.
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  • Effect of triazophos, fipronil and their mixture on miRNA expression in adult zebrafish

    Wang a, Xingxing   Zhou a, Shengli   Ding, Xianfeng   Zhu, Guonian   Guo, Jiangfeng  

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  • Discovery and identification of PIM-1 kinase inhibitors through a hybrid screening approach

    Shao, Mingfeng   Yuan, Yiming   Yu, Kun   Lei, Kai   Zhu, Guonian   Chen, Lijuan   Xiang, Mingli  

    PIM-1 kinase is an important therapeutic target in the treatment of cancer. Discovery and identification of PIM-1 Inhibitors with novel scaffolds are an effective way for developing potent therapeutic agents for the treatment of cancers. Here we proposed a hybrid screening approach which combines an optimal structure-based drug design strategy and a simple pharmacophore model to discover PIM-1 kinase inhibitors. With the proposed hybrid screening approach, the SPECS database containing 204,580 molecules was screened. In total, 89 hits were obtained. Forty three of them were purchased and tested in bioassays. Finally, 5 lead compounds with novel scaffolds were identified to exhibit promising antitumor activities against human leukemia cell line MV4-11, K-562 and human prostate cancer cell line PC-3 and DU145. Their values range from 4.40 to . Three hits with 3 different scaffolds were selected from these five hits for binding mode analysis. It was demonstrated that the subtle differences in the interactions of the representatives with PIM-1 kinase contribute to the different inhibitory activities. It was also demonstrated that the suggested hybrid screening approach is an effective method to discover PIM-1 inhibitors possessing different scaffolds. These leads have a strong likelihood to act as further starting points for us in the optimization and development of potent PIM-1 inhibitors.
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  • Effect of Reaction Format on a McAb-Based Heterologous ELISA for the Insecticide Parathion

    Liu, Yihua   Wang, Chunmei   Gui, Wenjun   Liang, Xiao   Bi, Jincheng   Huang, Guoyang   Zhu, Guonian  

    Based on the selected monoclonal antibody, the effect of three reaction formats on sensitivity, specificity, and determination ability for real samples were investigated. The results showed the antibody-coated format was the optimal assay for parathion determination. The sensitivity of the assay was 3.20ng/ml, with a detection limit of 0.40ng/ml, and the assay time was 1.5h. The average recoveries of parathion in river water, rice, cucumber, green soy bean, and cabbage were 98.56%, 89.46%, 99.25%, 118.57%, and 101.39%, respectively. In addition, when rice and cabbage extracts were analyzed by the assay and HPLC, the correlation was greater than 0.9.
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  • Characterization of Multihapten Antigens on Antibody Sensitivity and Specificity for Parathion

    Shi, Haiyan   Li, Hongxia   Hua, Xiude   Zheng, Zuntao   Zhu, Guonian   Wang, Minghua  

    Four multihapten antigens were conjugated to a single protein to obtain broad-specific polyclonal antibody characterization. The sensitivity and specificity of the polyclonal antibodies for parathion were evaluated with differences due to the structure of the determinant or the number of multihapten antigens. The sensitivity of immunoassay may decrease with a corresponding increase in the number of antigens in a multihapten immunogen or with an increase in complexity of the structure. The specificity of other analytes may broaden when the determinants of multihapten have similar structures.
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  • Development of a bead-based immunoassay for detection of triazophos and application validation

    Liang, Chizhou   Zou, Mingqiang   Guo, Lianghong   Gui, Wenjun   Zhu, Guonian  

    A bead-based competitive fluorescence immunoassay for the detection of triazophos has been developed. In this method, a conjugate of hapten and ovalbumin covalently bound to carboxylated fluorescent bead was used as a coating antigen and goat anti-mouse IgG/R-phycoerythrin conjugate was used as the fluorescent molecular probe. For standards (in 5% methanol in phosphate-buffered saline), the detection range was 0.0250 ng/ml and the average coefficient of variation (CV) was 8.9%. This bead-assay was highly specific for triazophos, and none of other the structurally similar compounds (diazinon, malathion, parathion and fenitrothion) were recognised (<0.01% cross-reactivity). Vegetable samples (cabbage, carrot, green pepper, spinach, eggplant) were spiked with triazophos in the range of 1.0100.0 ng/g and analysed by the bead-based immunoassay. The mean recovery and CV were 90.6 and 11.9%, respectively. The results confirmed that the bead-based fluorescence immunoassay is applicable for analysis and quantification of highly hydrophobic pesticide residues in vegetables.
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  • Quantum dot-based lateral flow immunoassay for detection of neonicotinoid residues in tea leaves

    Wang, Shuangjie   Liu, Ying   Jiao, Shasha   Zhao, Ying   Guo, Yirong   Wang, Mengcen   Zhu, Guonian  

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