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Now showing items 1 - 8 of 8

  • BisPNA-Assisted Detection of Double-stranded DNA via Electrochemical Impedance Spectroscopy

    Liu, Qianrui   Ma, Kefeng   Wen, Dongxiao   Sun, Haobo   Wang, Qiangwei   Kong, Jinming   Qiu, Yunliang   Li, Lianzhi   Chen, Wuqiao  

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  • Bioconcentration, metabolism and neurotoxicity of the organophorous flame retardant 1,3-dichloro 2-propyl phosphate (TDCPP) to zebrafish

    Wang, Qiangwei   Lam, James Chung-Wah   Man, Yin-Chung   Lai, Nelson Lok-Shun   Kwok, Karen Ying   Guo, Yong yong   Lam, Paul Kwan-Sing   Zhou, Bingsheng  

    Organophosphate flame retardants are ubiquitous environmental contaminants; however, knowledge is limited regarding their environmental health risks and toxicity. Here, we investigated the effects of acute and long-term exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) to the nervous system of zebrafish. Zebrafish embryos (2 h post-fertilization) were exposed to TDCPP (0-100 mu g/L) for 6 months up until sexual maturation. Concentrations of TDCPP and its metabolic product (bis(1,3-dichloro-2-propyl) phosphate, BDCPP) were measured in the tissues of 5 day post-fertilization (dpf) larvae. There was no effect on locomotion, acetylcholinesterase activity, levels of the neurotransmitters dopamine and serotonin, and expression of mRNAs and proteins related to central nervous system development (e.g., myelin basic protein, alpha 1-tubulin) in any exposure group. However, in adult fish, reductions of dopamine and serotonin levels were detected in the brains of females but not males. Downregulation of nervous system development genes was observed in both the male and female brain tissues. TDCPP concentrations were measured in adult fish tissues including the brain, and greater levels were detected in females. Our results showed that females are more sensitive to TDCPP stress than males in terms of TDCPP-induced neurotoxicity. We demonstrate that long-term exposure to lower concentrations of TDCPP in fish can lead to neurotoxicity. (C) 2014 Elsevier B.V. All rights reserved.
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  • Enantioselectivity of toxicological responses induced by maternal exposure of cis-bifenthrin enantiomers in zebrafish (Danio rerio) larvae

    Xiang, Dandan   Qiao, Kun   Song, Zhuoying   Shen, Shuyuan   Wang, Mengcen   Wang, Qiangwei  

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  • Exposure of zebrafish embryos/larvae to TDCPP alters concentrations of thyroid hormones and transcriptions of genes involved in the hypothalamic–pituitary–thyroid axis

    Wang, Qiangwei   Liang, Kang   Liu, Jingfu   Yang, Lihua   Guo, Yongyong   Liu, Chunsheng   Zhou, Bingsheng  

    Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) has been frequently detected in the environment and in various biota, including fish, and has been implicated in disruption of the thyroid endocrine system. In the present study, zebrafish (Danio rerio) embryos were exposed to different concentrations of TDCPP (10, 50, 100, 300 and 600 mu g/L) from 2 h post-fertilization (hpf) to 144 hpf. Developmental endpoints, and whole-body concentrations of thyroid hormones and transcriptional profiles of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were examined. Exposure to TDCPP caused a dose-dependent developmental toxicity, including decreased body weight, reduced hatching, survival and heartbeat rates, and increased malformation (spinal curvature). Treatment with the positive control chemical 3,3',5-triiodo-L-thyronine (T3) significantly decreased whole-body thyroxin (T4) concentrations, increased whole-body T3 concentrations, and upregulated mRNA expression involved in the HPT axis as a compensatory mechanism. These results suggested that the HPT axis in 144-hpf zebrafish larvae was responsive to chemical exposure and could be used to evaluate the effects of chemicals on the thyroid endocrine system. TDCPP exposure significantly decreased whole-body T4 concentrations and increased whole-body T3 concentrations, indicating thyroid endocrine disruption. The upregulation of genes related to thyroid hormone metabolism (dio1 and ugt1ab) might be responsible for decreased T4 concentrations. Treatment with TDCPP also significantly increased transcription of genes involved in thyroid hormone synthesis (tsh beta, slc5a5 and tg) and thyroid development (hhex, nkx2.1 and pax8) as a compensatory mechanism for decreased T4 concentrations. Taken together, these results suggest that TDCPP alters the transcription of genes involved in the HPT axis and changes whole-body concentrations of thyroid hormones in zebrafish embryos/larvae, thus causing an endocrine disruption of the thyroid system. (c) 2012 Elsevier B.V. All rights reserved.
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  • Developmental exposure to the organophosphorus flame retardant tris(1,3-dichloro-2-propyl) phosphate: Estrogenic activity, endocrine disruption and reproductive effects on zebrafish

    Wang, Qiangwei   Lam, James C.W.   Han, Jian   Wang, Xianfeng   Guo, Yongyong   Lam, Paul K.S.   Zhou, Bingsheng  

    Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is an organophosphate flame retardant that is detectable in the environment and biota, prompting concern over its risk to wildlife and human health. Our objective was to investigate whether long-term exposure to low concentrations of TDCPP can affect fish reproduction. Zebrafish embryos were exposed to low concentrations (0, 4, 20 and 100 mu g/L) of TDCPP from 2 h post-fertilization until sexual maturation. Exposure to TDCPP significantly increased plasma estradiol and testosterone levels in females, but had no effect in males. TDCPP exposure also caused a significant reduction in fecundity as indicated by decreased egg production. Real-time PCR was performed to examine selected genes in the hypothalamic-pituitary-gonadal (HPG) axis and liver. Principle component analysis (PCA) showed that sex hormone levels and fecundity were related to the mRNA level of several genes in the HPG axis. Furthermore, hepatic vitellogenin (vtg1 and vtg3) expression was upregulated in both females and males, suggesting TDCPP has estrogenic activity. Histological examination revealed promotion of oocyte maturation in the females, but retardation of spermiation in males. Reduced egg quality (e.g., egg diameter) and increased malformation rates were observed in the F1 generation. Chemical analysis showed significant levels of TDCPP and its metabolite bis(1,3-dichloro-2-propyl) phosphate in the gonads of males and females. In conclusion, long-term exposure to low concentrations of TDCPP impairs fish reproduction. (C) 2015 Elsevier B.V. All rights reserved.
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  • Bioconcentration and Transfer of the Organophorous Flame Retardant 1,3-Dichloro-2-propyl Phosphate Causes Thyroid Endocrine Disruption and Developmental Neurotoxicity in Zebrafish Larvae

    Wang, Qiangwei   Lai, Nelson Lok-Shun   Wang, Xianfeng   Guo, Yongyong   Lam, Paul Kwan-Sing   Lam, James Chung-Wah   Zhou, Bingsheng  

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  • Bioconcentration and metabolism of BDE-209 in the presence of titanium dioxide nanoparticles and impact on the thyroid endocrine system and neuronal development in zebrafish larvae

    Wang, Qiangwei   Chen, Qi   Zhou, Peng   Li, Wenwen   Wang, Junxia   Huang, Changjiang   Wang, Xianfeng   Lin, Kuangfei   Zhou, Bingsheng  

    Interactions between organic toxicants and nanoparticles (NPs) in the aquatic environment may modify toxicant bioavailability and consequently the toxicant's environmental fate and toxicity. Therefore, we investigated the influence of titanium dioxide NPs (nano-TiO2) on deca-BDE (BDE-209; a polybrominated diphenyl ether congener) bioconcentration, metabolism and its effects on the thyroid endocrine system in zebrafish (Danio rerio) larvae. Zebrafish embryos were exposed to various concentrations of BDE-209 alone or in combination with nano-TiO2 (0.1 mg/L) until 7-day post-fertilization. Nano-TiO2 can adsorb BDE-209 and nano-TiO2 is taken up into developing zebrafish larvae. Chemical measurements showed that BDE-209 was bioconcentrated and metabolized in zebrafish larvae, and BDE-209 uptake was enhanced by nano-TiO2. Furthermore, increased BDE-209 metabolites were detected in larvae co-exposed with nano-TiO2. BDE-209 exposure significantly increased whole-body thyroid hormone contents (T-3 and T-4); T-4 content significantly increased in the larvae co-exposed with nano-TiO2. Nano-TiO2 exposure alone did not induce generation of reactive oxygen species, lipid peroxidative oxidation, gene transcription or thyroid hormone levels. Upregulation of several gene transcriptions (tsh beta, tg, diO(2)) in the hypothalamic-pituitary-thyroid axis was also observed. Furthermore, co-exposure of nano-TiO2 and BDE-209 caused a decrease in locomotion activity and downregulation of specific genes and proteins involved in the central nervous system of developing zebrafish larvae (e.g. myelin basic protein and alpha 1-tubulin). These results indicate nano-TiO2 enhances BDE-209 bioavailability and metabolism, leading to thyroid endocrine disruption and developmental neurotoxicity in zebrafish.
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  • Effect of Iron Oxide Promoted Sulfated Zirconia on the Oxidative Efficiency of H\r 2\r O\r 2\r /O\r 3\r for Acetic Acid Degradation in Strong Acidic Water

    Wang, Qiangwei   Shen, Tongdong   Tong, Shaoping  

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