The Experts below are selected from a list of 7701 Experts worldwide ranked by ideXlab platform
Xiaoqiang Chu - One of the best experts on this subject based on the ideXlab platform.
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degradation of chlorpyrifos alone and in combination with Chlorothalonil and their effects on soil microbial populations
Journal of Environmental Sciences-china, 2008Co-Authors: Xiaoqiang Chu, Min Shan, Hua Fang, Xiao Wang, Xuedong Pan, Bo FengAbstract:Abstract In practice, pesticides are usually applied simultaneously or one after another for crop protection, and this type of pesticide application often leads to a combined contamination of pesticide residues in the soil environment. A laboratory study was conducted to investigate the influence of Chlorothalonil on chlorpyrifos degradation and its effects on soil bacterial, fungal, and actinomycete populations. Under the experimental conditions here, the half-lives of chlorpyrifos alone, and in combination with Chlorothalonil, at the recommended and double dosages, were measured to be 3.24, 2.77, and 2.63 d, respectively. Chlorpyrifos degradation was not significantly altered by its combination with Chlorothalonil. However, the inhibitory effect of chlorpyrifos on soil microorganisms was increased by its combination with Chlorothalonil, and the increase was related to the levels of Chlorothalonil added. Compared to those in the controls, the populations of bacteria, fungi, and actinomycetes were significantly reduced by 44.1%, 61.1%, and 72.8%, respectively, on the first day after treatment (DAT) by chlorpyrifos alone. With the addition of Chlorothalonil, the inhibition was increased to 55.2%, 79.3%, and 85.8% at the recommended dosage, and 86.0%, 94.1%, and 90.8% at the double dosage, at one DAT, respectively. The results suggested that combined effects should be taken into account to assess the actual impacts of pesticide applications.
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Responses of soil microorganisms and enzymes to repeated applications of Chlorothalonil.
Journal of agricultural and food chemistry, 2006Co-Authors: Min Shan, Hua Fang, Xiao Wang, Xiaoqiang ChuAbstract:Introduction of anthropogenic chemicals into soil may have lasting effects on soil microbial activities and thus soil health. This study was conducted with Chlorothalonil to evaluate its effects on soil bacterial, fungal, and actinomycete populations and soil enzymes (acid phosphatase, alkaline phosphatase, urease, catalase, and invertase) after repeated applications. After the first addition of Chlorothalonil, the soil bacterial and actinomycete populations were significantly reduced, whereas the population of soil fungi was unchanged. The most marked inhibition on soil microorganisms was observed after the second pesticide addition. However, after initial variations, soil bacteria, fungi, and actinomycetes adapted gradually to Chlorothalonil, and the negative effects became transient and weaker following the third and fourth treatments. The inhibitory effect of repeated Chlorothalonil applications on soil enzymes followed a similar trend to that on soil microorganisms. Repeated Chlorothalonil applications did not result in significant changes in its persistence. Three bacterial strains capable of utilizing Chlorothalonil as a sole source of carbon and energy for growth were isolated 21 days after the fourth treatment with Chlorothalonil, which indicated that the capability of soil microorganisms for degrading Chlorothalonil was formed during the experiment.
Min Shan - One of the best experts on this subject based on the ideXlab platform.
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degradation of chlorpyrifos alone and in combination with Chlorothalonil and their effects on soil microbial populations
Journal of Environmental Sciences-china, 2008Co-Authors: Xiaoqiang Chu, Min Shan, Hua Fang, Xiao Wang, Xuedong Pan, Bo FengAbstract:Abstract In practice, pesticides are usually applied simultaneously or one after another for crop protection, and this type of pesticide application often leads to a combined contamination of pesticide residues in the soil environment. A laboratory study was conducted to investigate the influence of Chlorothalonil on chlorpyrifos degradation and its effects on soil bacterial, fungal, and actinomycete populations. Under the experimental conditions here, the half-lives of chlorpyrifos alone, and in combination with Chlorothalonil, at the recommended and double dosages, were measured to be 3.24, 2.77, and 2.63 d, respectively. Chlorpyrifos degradation was not significantly altered by its combination with Chlorothalonil. However, the inhibitory effect of chlorpyrifos on soil microorganisms was increased by its combination with Chlorothalonil, and the increase was related to the levels of Chlorothalonil added. Compared to those in the controls, the populations of bacteria, fungi, and actinomycetes were significantly reduced by 44.1%, 61.1%, and 72.8%, respectively, on the first day after treatment (DAT) by chlorpyrifos alone. With the addition of Chlorothalonil, the inhibition was increased to 55.2%, 79.3%, and 85.8% at the recommended dosage, and 86.0%, 94.1%, and 90.8% at the double dosage, at one DAT, respectively. The results suggested that combined effects should be taken into account to assess the actual impacts of pesticide applications.
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Responses of soil microorganisms and enzymes to repeated applications of Chlorothalonil.
Journal of agricultural and food chemistry, 2006Co-Authors: Min Shan, Hua Fang, Xiao Wang, Xiaoqiang ChuAbstract:Introduction of anthropogenic chemicals into soil may have lasting effects on soil microbial activities and thus soil health. This study was conducted with Chlorothalonil to evaluate its effects on soil bacterial, fungal, and actinomycete populations and soil enzymes (acid phosphatase, alkaline phosphatase, urease, catalase, and invertase) after repeated applications. After the first addition of Chlorothalonil, the soil bacterial and actinomycete populations were significantly reduced, whereas the population of soil fungi was unchanged. The most marked inhibition on soil microorganisms was observed after the second pesticide addition. However, after initial variations, soil bacteria, fungi, and actinomycetes adapted gradually to Chlorothalonil, and the negative effects became transient and weaker following the third and fourth treatments. The inhibitory effect of repeated Chlorothalonil applications on soil enzymes followed a similar trend to that on soil microorganisms. Repeated Chlorothalonil applications did not result in significant changes in its persistence. Three bacterial strains capable of utilizing Chlorothalonil as a sole source of carbon and energy for growth were isolated 21 days after the fourth treatment with Chlorothalonil, which indicated that the capability of soil microorganisms for degrading Chlorothalonil was formed during the experiment.
Kelly R Munkittrick - One of the best experts on this subject based on the ideXlab platform.
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hepatic gene expression profiling in zebrafish danio rerio exposed to the fungicide Chlorothalonil
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics, 2016Co-Authors: Anny Sanchez B Garayzar, Paulina Bahamonde, Christopher J Martyniuk, Miguel Betancourt, Kelly R MunkittrickAbstract:Chlorothalonil (tetrachloroisophtalonitrile) is a fungicide that is widely used on agricultural crops around the world and as such, it is a ubiquitous aquatic contaminant. Despite high usage, the effects of this fungicide on non-target aquatic organisms have not been fully investigated. The aim of the present study was to (1) determine the effects of Chlorothalonil toxicity on adult male zebrafish (Danio rerio) and (2) characterize the effects of Chlorothalonil on gene expression patterns in the liver using two different concentrations of the fungicide, 0.007mg/L (environmentally-relevant) and 0.035mg/L (sublethal). These concentrations were selected from range-finding experiments that showed that zebrafish survival was significantly different from control animals at concentrations higher than 0.035mg/L but not below. Male zebrafish in both treatments of Chlorothalonil showed a decrease in liversomatic index. A commercial D. rerio microarray (4×44K) was used to determine gene expression profiles in male zebrafish liver following a 96h toxicological assay. Microarray analysis revealed that males exposed to both 0.007mg/L or 0.035mg/L of Chlorothalonil showed increased transcriptional sub-networks related to cell division and DNA damage and decreased expression of gene networks associated with reproduction, immunity, and xenobiotic clearance. This study improves knowledge regarding whole animal exposures to Chlorothalonil and identifies molecular signaling cascades that are sensitive to this fungicide in the fish liver.
Christopher J Martyniuk - One of the best experts on this subject based on the ideXlab platform.
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hepatic gene expression profiling in zebrafish danio rerio exposed to the fungicide Chlorothalonil
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics, 2016Co-Authors: Anny Sanchez B Garayzar, Paulina Bahamonde, Christopher J Martyniuk, Miguel Betancourt, Kelly R MunkittrickAbstract:Chlorothalonil (tetrachloroisophtalonitrile) is a fungicide that is widely used on agricultural crops around the world and as such, it is a ubiquitous aquatic contaminant. Despite high usage, the effects of this fungicide on non-target aquatic organisms have not been fully investigated. The aim of the present study was to (1) determine the effects of Chlorothalonil toxicity on adult male zebrafish (Danio rerio) and (2) characterize the effects of Chlorothalonil on gene expression patterns in the liver using two different concentrations of the fungicide, 0.007mg/L (environmentally-relevant) and 0.035mg/L (sublethal). These concentrations were selected from range-finding experiments that showed that zebrafish survival was significantly different from control animals at concentrations higher than 0.035mg/L but not below. Male zebrafish in both treatments of Chlorothalonil showed a decrease in liversomatic index. A commercial D. rerio microarray (4×44K) was used to determine gene expression profiles in male zebrafish liver following a 96h toxicological assay. Microarray analysis revealed that males exposed to both 0.007mg/L or 0.035mg/L of Chlorothalonil showed increased transcriptional sub-networks related to cell division and DNA damage and decreased expression of gene networks associated with reproduction, immunity, and xenobiotic clearance. This study improves knowledge regarding whole animal exposures to Chlorothalonil and identifies molecular signaling cascades that are sensitive to this fungicide in the fish liver.
Meirong Zhao - One of the best experts on this subject based on the ideXlab platform.
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the identification of the metabolites of Chlorothalonil in zebrafish danio rerio and their embryo toxicity and endocrine effects at environmentally relevant levels
Environmental Pollution, 2016Co-Authors: Quan Zhang, Lu Yan, Meirong ZhaoAbstract:Chlorothalonil is a broad spectrum fungicide with high annual production and environmental contamination. Despite its high consumption, studies regarding the potential ecological risks of Chlorothalonil, especially its metabolites, to aquatic organisms are still limited. In this study, we selected the zebrafish (Danio rerio) as the in vivo model and first identified the metabolite (4-hydroxyChlorothalonil) of Chlorothalonil in zebrafish by tandem quadrupole/orthogonal-acceleration time-of-flight (Q-TOF). Then, the in vivo and in vitro models were applied to comprehensively estimate the embryo toxicity and potential endocrine effect of Chlorothalonil and 4-hydroxyChlorothalonil. The data from zebrafish embryo toxicity showed that the lowest observed effect concentrations of both Chlorothalonil and 4-hydroxyChlorothalonil were 50 μg/L after 96 h of exposure. The mortality rate of the 4-hydroxyChlorothalonil was 2.6-fold higher than that of the parent compound at the concentration of 50 μg/L. Dual-luciferase reporter gene assays indicated that both Chlorothalonil and 4-hydroxyChlorothalonil exerted estrogen receptor α (ERα) agonist activity with REC20 values of 2.4 × 10-8 M and 3.6 × 10-8 M, respectively. However, only 4-hydroxyChlorothalonil exhibited both thyroid receptor β (TRβ) agonistic and antagonistic activities. Lastly, we employed molecular docking to predict the binding affinity of Chlorothalonil and 4-hydroxyChlorothalonil with ERα or TRβ. The results revealed that the potential endocrine effect of Chlorothalonil and 4-hydroxychlorothaloni might be attributed to the different binding affinities with the receptors. In conclusion, our studies revealed that 4-hydroxyChlorothalonil exhibited potent endocrine-disrupting effects compared to its parent compound, Chlorothalonil. The results provided here remind us that the assessment of the potential ecological and health risks of the metabolites of fungicides in addition to their parent compounds should arouse great concerns.