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Yuezhong Wen - One of the best experts on this subject based on the ideXlab platform.
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new target in an old enemy herbicide r Dichlorprop induces ferroptosis like death in plants
Journal of Agricultural and Food Chemistry, 2021Co-Authors: Siyu Chen, Hui Chen, Zunwei Chen, Jinye Huang, Yuezhong WenAbstract:Iron is an essential microelement in plants that is involved in several growth processes. The use of herbicides may cause the abnormal aggregation of iron in leaves, but the regulatory mechanisms underlying this phenomenon remain unclear. Here, we show that chiral herbicide (R)-Dichlorprop ((R)-DCPP) triggers ferroptosis-like death in Arabidopsis thaliana. (R)-DCPP led to reactive oxygen species (ROS) accumulation and iron aggregation, and these processes were iron dependent. Under (R)-DCPP treatment, ROS, lipid hydrogen peroxides, and malondialdehyde were significantly accumulated. In addition, (R)-DCPP induced the depletion of glutathione, ascorbic acid, and glutathione peroxidase as well as the accumulation of toxic lipid peroxides. Thus, oxidation imbalance led to cell death, and this mode of action could be inhibited by the ferroptosis inhibitor ferrostatin-1 or ciclopirox olamine. NADPH oxidases were found to be involved in herbicide-induced ROS accumulation, and lipoxygenase and NADPH cytochrome P450 oxidase were shown to positively regulate (R)-DCPP-induced lipid peroxidation. Overall, these results indicate that the iron- and ROS-dependent signaling cascades were involved in the (R)-DCPP-induced phytotoxicity pathway, which disrupted the structure of plant cell membranes and triggered ferroptosis. Generally, this study provides new insight into the mechanisms of pesticide phytotoxicity and suggests new therapeutic directions to protect nontarget plants.
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phytotoxicity of the chiral herbicide Dichlorprop cross talk between nitric oxide reactive oxygen species and phytohormones
Science of The Total Environment, 2021Co-Authors: Hui Chen, Yongxiang Qin, Yuezhong WenAbstract:Abstract Nitric oxide (NO), reactive oxygen species (ROS), and phytohormones in plants often initiate responses to sources of abiotic stress. However, we have a poor understanding of the cross-talk between NO, ROS, and phytohormones during exogenous chiral auxin-induced phytotoxicity. In this study, the toxicity of the chiral synthetic auxin herbicide Dichlorprop (DCPP) to Arabidopsis thaliana, as well as the mutual regulation of NO, hydrogen peroxide (H2O2), superoxide anion (O2.-), and phytohormones at the enantiomeric level was investigated. The ROS production exhibited an enantioselective manner, further, that was positively correlated with the change of the morphological indicators. This confirmed that ROS played an important role in the enantioselective effect of DCPP. The distribution of ROS and NO was partially overlapped, indicating that the production of NO may be affected by ROS, and also related to the degree of plant damage. In terms of phytohormones, the level of salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) in the whole plant increased as the (R)-DCPP concentration applied increased, however, the trend has changed, when the data of leaves and roots was discussed separately. The results revealed that the redistribution of phytohormones may exist between leaves and roots, caused by the joint action of ROS and NO. The differences in the biological activity identified between the two enantiomers in this study enhance our understanding of the toxicity mechanism of exogenous auxin via their effects on phytohormones.
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enantioselective phytotoxic disturbances of fatty acids in arabidopsis thaliana by Dichlorprop
Environmental Science & Technology, 2019Co-Authors: Siyu Chen, Yuezhong Wen, Hui Chen, Zunwei Chen, Wei-ping LiuAbstract:Plant fatty acids have indispensable physiological functions and nutritional value. However, the overuse of herbicides may cause phytotoxic disturbances of fatty acids in nontarget plants while spraying for weeds. Evidence has shown that the herbicide Dichlorprop can inhibit the activity of acetyl-CoA carboxylase (ACCase), a key enzyme involved in fatty acid synthesis. However, the enantioselective phytotoxic effects of Dichlorprop enantiomers ((R)-Dichlorprop and (S)-Dichlorprop) on fatty acids and their related mechanisms remain unclear. To solve this issue, the enantioselective phytotoxicity of Dichlorprop in the model plant species Arabidopsis thaliana (A. thaliana) with a focus on fatty acids was evaluated for the first time. The results indicated a significant difference in enantioselectivity and that exposure to (R)-Dichlorprop can cause marked fatty acid disturbances in nontarget plant species. Specifically, (R)-Dichlorprop decreased the content of three fatty acids by more than 50% by inhibiting the activity of ACCase. In addition, increased malondialdehyde (MDA) and lipid hydroperoxides (LOOHs) contents and membrane permeability reflected herbicide-induced lipid peroxidation, which decreased the unsaturation of fatty acids in membranes and further influenced membrane composition and function. Moreover, an increased level of glutathione peroxidase (GPX) and cytochrome P450 (CYP450) reflected a plant stress-induced response. To summarize, fatty acids represent a new perspective for evaluating the toxicity of chiral pesticides, contributing to a better understanding of the enantioselective phytotoxicity and mechanisms of Dichlorprop, and providing evidence for herbicide security and risk assessments.
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Dichlorprop induced structural changes of lhcii chiral macroaggregates associated with enantioselective toxicity to scnedesmus obliquus
Aquatic Toxicology, 2019Co-Authors: Hui Chen, Zunwei Chen, Chensi Shen, Babar Aijaz Ali, Yuezhong WenAbstract:Abstract The enantioselective toxic mechanisms of chiral herbicides in photosynthetic organisms are closely related to the production of reactive oxygen species (ROS) production, however, there are few reports on how the enantioselective production of ROS can be triggered. In suboptimal conditions, photosynthesis is one of the most important processes in the production of ROS, especially in the process of light utilization and electron transfer. In this study, we investigated the interactions between chiral herbicide Dichlorprop (DCPP) enantiomers and the chiral macroaggregates of the photosynthetic light-harvesting chlorophyll a/b pigment-protein complexes (LHCII) in Scenedesmus obliquus, which is of great significance in capturing and utilizing sun light, and also in dissipating the excess excitation energy. The results of the circular dichroism indicated that DCPP induced the structural changes of the LHCII chiral macroaggregates in an enantioselective manner and that the (R)-DCPP treated-group showed a bigger change accompanied by a changed enantioselective dissipation of the excitation energy. The excitation energy was excessed in DCPP treated-groups and the degree of excess was enantioselective and the detrimental non-chemical energy triggered the enantioselective production of ROS, that induced the enantioselective toxicity to green algae S. obliquus. Overall, this study has identified that how the enantioselective production of ROS can be triggered in chloroplasts; this can help to reveal the enantioselective mechanisms of chiral herbicides to photosynthetic organisms.
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enantioselective phytotoxicity of Dichlorprop to arabidopsis thaliana the effect of cytochrome p450 enzymes and the role of fe
Environmental Science & Technology, 2017Co-Authors: Zunwei Chen, Yuezhong Wen, Hui Chen, Jia Wang, Wei-ping LiuAbstract:The ecotoxicology effects of chiral herbicides have long been recognized and have drawn increasing attention. The toxic mechanisms of herbicides in plants are involved in production of reactive oxygen species (ROS) and cause damage to target enzymes, but the relationship between these two factors in the enantioselectivity of chiral herbicides has rarely been investigated. Furthermore, even though cytochromes P450 enzymes (CYP450s) have been related to the phytotoxicity of herbicides, their roles in the enantioselectivity of chiral herbicides have yet to be explored. To solve this puzzle, the CYP450s suicide inhibitor 1-aminobenzotriazole (ABT) was added to an exposure system made from Dichlorprop (DCPP) enantiomers in the model plant Arabidopsis thaliana. The results indicated that different phytotoxicities of DCPP enantiomers by causing oxidative stress and acetyl-CoA carboxylase (ACCase) damage were observed in the presence and the absence of ABT. The addition of ABT decreased the toxicity of (R)-DCPP but was not significantly affected that of (S)-DCPP, resulting in smaller differences between enantiomers. Furthermore, profound differences were also observed in Fe uptake and distribution, exhibiting different distribution patterns in A. thaliana leaves exposed to DCPP and ABT, which helped bridge the relationship between ROS production and target enzyme ACCase damage through the function of CYP450s. These results offer an opportunity for a more-comprehensive understanding of chiral herbicide action mechanism and provide basic evidence for risk assessments of chiral herbicides in the environment.
Wei-ping Liu - One of the best experts on this subject based on the ideXlab platform.
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enantioselective phytotoxic disturbances of fatty acids in arabidopsis thaliana by Dichlorprop
Environmental Science & Technology, 2019Co-Authors: Siyu Chen, Yuezhong Wen, Hui Chen, Zunwei Chen, Wei-ping LiuAbstract:Plant fatty acids have indispensable physiological functions and nutritional value. However, the overuse of herbicides may cause phytotoxic disturbances of fatty acids in nontarget plants while spraying for weeds. Evidence has shown that the herbicide Dichlorprop can inhibit the activity of acetyl-CoA carboxylase (ACCase), a key enzyme involved in fatty acid synthesis. However, the enantioselective phytotoxic effects of Dichlorprop enantiomers ((R)-Dichlorprop and (S)-Dichlorprop) on fatty acids and their related mechanisms remain unclear. To solve this issue, the enantioselective phytotoxicity of Dichlorprop in the model plant species Arabidopsis thaliana (A. thaliana) with a focus on fatty acids was evaluated for the first time. The results indicated a significant difference in enantioselectivity and that exposure to (R)-Dichlorprop can cause marked fatty acid disturbances in nontarget plant species. Specifically, (R)-Dichlorprop decreased the content of three fatty acids by more than 50% by inhibiting the activity of ACCase. In addition, increased malondialdehyde (MDA) and lipid hydroperoxides (LOOHs) contents and membrane permeability reflected herbicide-induced lipid peroxidation, which decreased the unsaturation of fatty acids in membranes and further influenced membrane composition and function. Moreover, an increased level of glutathione peroxidase (GPX) and cytochrome P450 (CYP450) reflected a plant stress-induced response. To summarize, fatty acids represent a new perspective for evaluating the toxicity of chiral pesticides, contributing to a better understanding of the enantioselective phytotoxicity and mechanisms of Dichlorprop, and providing evidence for herbicide security and risk assessments.
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enantioselective phytotoxicity of Dichlorprop to arabidopsis thaliana the effect of cytochrome p450 enzymes and the role of fe
Environmental Science & Technology, 2017Co-Authors: Zunwei Chen, Yuezhong Wen, Hui Chen, Jia Wang, Wei-ping LiuAbstract:The ecotoxicology effects of chiral herbicides have long been recognized and have drawn increasing attention. The toxic mechanisms of herbicides in plants are involved in production of reactive oxygen species (ROS) and cause damage to target enzymes, but the relationship between these two factors in the enantioselectivity of chiral herbicides has rarely been investigated. Furthermore, even though cytochromes P450 enzymes (CYP450s) have been related to the phytotoxicity of herbicides, their roles in the enantioselectivity of chiral herbicides have yet to be explored. To solve this puzzle, the CYP450s suicide inhibitor 1-aminobenzotriazole (ABT) was added to an exposure system made from Dichlorprop (DCPP) enantiomers in the model plant Arabidopsis thaliana. The results indicated that different phytotoxicities of DCPP enantiomers by causing oxidative stress and acetyl-CoA carboxylase (ACCase) damage were observed in the presence and the absence of ABT. The addition of ABT decreased the toxicity of (R)-DCPP but was not significantly affected that of (S)-DCPP, resulting in smaller differences between enantiomers. Furthermore, profound differences were also observed in Fe uptake and distribution, exhibiting different distribution patterns in A. thaliana leaves exposed to DCPP and ABT, which helped bridge the relationship between ROS production and target enzyme ACCase damage through the function of CYP450s. These results offer an opportunity for a more-comprehensive understanding of chiral herbicide action mechanism and provide basic evidence for risk assessments of chiral herbicides in the environment.
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Enantioselective Phytotoxicity of Dichlorprop to Arabidopsis thaliana: The Effect of Cytochrome P450 Enzymes and the Role of Fe
2017Co-Authors: Zunwei Chen, Yuezhong Wen, Hui Chen, Jia Wang, Wei-ping LiuAbstract:The ecotoxicology effects of chiral herbicides have long been recognized and have drawn increasing attention. The toxic mechanisms of herbicides in plants are involved in production of reactive oxygen species (ROS) and cause damage to target enzymes, but the relationship between these two factors in the enantioselectivity of chiral herbicides has rarely been investigated. Furthermore, even though cytochromes P450 enzymes (CYP450s) have been related to the phytotoxicity of herbicides, their roles in the enantioselectivity of chiral herbicides have yet to be explored. To solve this puzzle, the CYP450s suicide inhibitor 1-aminobenzotriazole (ABT) was added to an exposure system made from Dichlorprop (DCPP) enantiomers in the model plant Arabidopsis thaliana. The results indicated that different phytotoxicities of DCPP enantiomers by causing oxidative stress and acetyl-CoA carboxylase (ACCase) damage were observed in the presence and the absence of ABT. The addition of ABT decreased the toxicity of (R)-DCPP but was not significantly affected that of (S)-DCPP, resulting in smaller differences between enantiomers. Furthermore, profound differences were also observed in Fe uptake and distribution, exhibiting different distribution patterns in A. thaliana leaves exposed to DCPP and ABT, which helped bridge the relationship between ROS production and target enzyme ACCase damage through the function of CYP450s. These results offer an opportunity for a more-comprehensive understanding of chiral herbicide action mechanism and provide basic evidence for risk assessments of chiral herbicides in the environment
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enantioselectivity tuning of chiral herbicide Dichlorprop by copper roles of reactive oxygen species
Environmental Science & Technology, 2011Co-Authors: Yuezhong Wen, Hui Chen, Chensi Shen, Meirong Zhao, Wei-ping LiuAbstract:Reactive oxygen species (ROS) are considered to be the key players in cell toxicity. However, cross talk between the enantioselective toxicity of pesticides, heavy metals, and ROS is poorly understood. To decipher the puzzle, the effects of copper (Cu) on the enantioselective ecotoxicity of the chiral pesticide Dichlorprop (DCPP) to Scenedesmus obliquus were investigated. The results showed that the presence of DCPP and Cu, both individually and in combination, caused a sudden increase of ROS. This in turn stimulated the response of antioxidant defenses, impaired subcellular structure and physiological function, and finally resulted in cell growth inhibition. In the absence of Cu, ROS production after exposure to the herbicidally active (R)-enantiomer was higher than that of the (S)-enantiomer, suggesting a preference for an (R)-enantiomer-induced production of ROS. When DCPP and Cu were both added to algae simultaneously, (R)-DCPP preferentially induced production of ROS was observed. However, the enantioselective induced production of ROS was reversed when DCPP was mixed with Cu for 24 h prior to addition to the algae solution. It was also found that the generation of ROS, antioxidant response, and growth inhibition rate in Scenedesmus obliquus were all (R)-enantiomer preferentially induced. These findings implied that ROS play a primary role in chemical contaminant toxicity, and interactions between contaminants can tune the enantioselectivity of chiral herbicides, which should be considered in future risk assessment.
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elucidation of the enantioselective enzymatic hydrolysis of chiral herbicide Dichlorprop methyl by chemical modification
Journal of Agricultural and Food Chemistry, 2011Co-Authors: Yuezhong Wen, Zhaohua Fang, Shulin Zhuang, Wei-ping LiuAbstract:Up to 25% of the current pesticides are chiral, the molecules have chiral centers, but most of them are used as racemates. In most cases, enantiomers of chiral pesticides have different fates in th...
Agnethe Christiansen - One of the best experts on this subject based on the ideXlab platform.
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sorption of bentazone Dichlorprop mcpa and propiconazole in reference soils from norway
Journal of Environmental Quality, 2001Co-Authors: Christian W Thorstensen, Olav Lode, Ole Martin Eklo, Agnethe ChristiansenAbstract:Sorption-desorption kinetic and isotherm studies were performed by the batch equilibrium technique in three Norwegian soils. The soils were a fine sandy loam, a loam, and a soil of highly decomposed organic material. Two commercially formulations were used, Triagran-P and Tilt, containing either a mixture of bentazone [3-isopropyl-1H-2, 1,3-benzothiadiazin-4(3H)-one 2,2-dioxide], Dichlorprop [(R)-2-(2, 4-dichlorophenoxy)-propionic acid], and MCPA [(4-chloro-2-methylphenoxy)acetic acid], or propiconazole [(±)1-(2-(2,4-dichlorophenyl))-4-propyl-1,3-dioxolan-2-ylmethyl)-1H-1,2,4-triazole] alone. Sorption-desorption equilibrium occurred within 10 h for all pesticides. The Freundlich isotherms indicated nonlinear sorption of bentazone, Dichlorprop, MCPA, and propiconazole. For all pesticides the highest Freundlich adsorption coefficient (K F ) values were in the soil with highest organic content and lowest pH. For the fine sandy loam and loam, which are representative Norwegian agricultural soils, the results indicate that bentazone, Dichlorprop, and MCPA are mobile with K F values ranging from 0.07 to 1.50 mg t-1/n kg -1 L 1/n . Propiconazole is much less mobile with K F values ranging from 27.00 to 36.02 mg 1 1/n kg -1 L 1/n in the agricultural soils.
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determination of bentazone Dichlorprop and mcpa in different soils by sodium hydroxide extraction in combination with solid phase preconcentration
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Christian W Thorstensen, Agnethe ChristiansenAbstract:A method for the extraction of bentazone, Dichlorprop, and MCPA in three selected Norwegian soils of different textures is described. Initially three different extraction methods were tested on one soil type. All methods gave recoveries >80% for the pesticide mixture, but extraction with sodium hydroxide in combination with solid-phase preconcentration was used for further recovery tests with soils of different properties spiked at four herbicide concentration levels (0.001−10 μg/g of wet soil). The method was rapid and easy and required a minimum of organic solvents. The recoveries were in the range of 82−109, 80−123, and 45−91% for the soils containing 1.4 (Hole), 2.5 (Kroer), and 37.8% (Froland) organic carbon, respectively. Limits of quantification using GC-MS were 0.0003 μg/g of wet soil for bentazone and 0.0001 μg/g of wet soil for both Dichlorprop and MCPA. Keywords: Soil extraction; solid-phase extraction; phenoxy acids; bentazone
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development of a solid phase extraction method for phenoxy acids and bentazone in water and comparison to a liquid liquid extraction method
Journal of Agricultural and Food Chemistry, 2000Co-Authors: Christian W Thorstensen, Olav Lode, Agnethe ChristiansenAbstract:A rapid solid-phase extraction (SPE) method was developed for the determination of bentazone and the phenoxy acids 2,4-D, Dichlorprop, MCPA, and mecoprop in Norwegian environmental water samples. Cartridges with a high-capacity cross-linked polystyrene-based polymer were used for off-line preconcentration. The effects of elution solvent, elution volume, sample volume, sorbent mass, pH, and flow rate on the recoveries of the pesticides were investigated using HPLC. Average recovery of >90% was achieved with 500 mg sorbents using 2 mL of methanol with 5% NH3 as elution solvent. The recoveries were independent of sample pH in the tested range of pH 1−7. Using a sample volume of 200 mL, the limits of determination for the phenoxy acids and bentazone are 0.02 μg/L. Sample volumes up to 2000 mL at a flow rate of 60 mL/min could be handled without any loss of analytes, which makes it possible to lower the limits of determination. The SPE method was compared to a routinely used liquid−liquid extraction method. Th...
Hui Chen - One of the best experts on this subject based on the ideXlab platform.
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new target in an old enemy herbicide r Dichlorprop induces ferroptosis like death in plants
Journal of Agricultural and Food Chemistry, 2021Co-Authors: Siyu Chen, Hui Chen, Zunwei Chen, Jinye Huang, Yuezhong WenAbstract:Iron is an essential microelement in plants that is involved in several growth processes. The use of herbicides may cause the abnormal aggregation of iron in leaves, but the regulatory mechanisms underlying this phenomenon remain unclear. Here, we show that chiral herbicide (R)-Dichlorprop ((R)-DCPP) triggers ferroptosis-like death in Arabidopsis thaliana. (R)-DCPP led to reactive oxygen species (ROS) accumulation and iron aggregation, and these processes were iron dependent. Under (R)-DCPP treatment, ROS, lipid hydrogen peroxides, and malondialdehyde were significantly accumulated. In addition, (R)-DCPP induced the depletion of glutathione, ascorbic acid, and glutathione peroxidase as well as the accumulation of toxic lipid peroxides. Thus, oxidation imbalance led to cell death, and this mode of action could be inhibited by the ferroptosis inhibitor ferrostatin-1 or ciclopirox olamine. NADPH oxidases were found to be involved in herbicide-induced ROS accumulation, and lipoxygenase and NADPH cytochrome P450 oxidase were shown to positively regulate (R)-DCPP-induced lipid peroxidation. Overall, these results indicate that the iron- and ROS-dependent signaling cascades were involved in the (R)-DCPP-induced phytotoxicity pathway, which disrupted the structure of plant cell membranes and triggered ferroptosis. Generally, this study provides new insight into the mechanisms of pesticide phytotoxicity and suggests new therapeutic directions to protect nontarget plants.
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phytotoxicity of the chiral herbicide Dichlorprop cross talk between nitric oxide reactive oxygen species and phytohormones
Science of The Total Environment, 2021Co-Authors: Hui Chen, Yongxiang Qin, Yuezhong WenAbstract:Abstract Nitric oxide (NO), reactive oxygen species (ROS), and phytohormones in plants often initiate responses to sources of abiotic stress. However, we have a poor understanding of the cross-talk between NO, ROS, and phytohormones during exogenous chiral auxin-induced phytotoxicity. In this study, the toxicity of the chiral synthetic auxin herbicide Dichlorprop (DCPP) to Arabidopsis thaliana, as well as the mutual regulation of NO, hydrogen peroxide (H2O2), superoxide anion (O2.-), and phytohormones at the enantiomeric level was investigated. The ROS production exhibited an enantioselective manner, further, that was positively correlated with the change of the morphological indicators. This confirmed that ROS played an important role in the enantioselective effect of DCPP. The distribution of ROS and NO was partially overlapped, indicating that the production of NO may be affected by ROS, and also related to the degree of plant damage. In terms of phytohormones, the level of salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) in the whole plant increased as the (R)-DCPP concentration applied increased, however, the trend has changed, when the data of leaves and roots was discussed separately. The results revealed that the redistribution of phytohormones may exist between leaves and roots, caused by the joint action of ROS and NO. The differences in the biological activity identified between the two enantiomers in this study enhance our understanding of the toxicity mechanism of exogenous auxin via their effects on phytohormones.
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enantioselective phytotoxic disturbances of fatty acids in arabidopsis thaliana by Dichlorprop
Environmental Science & Technology, 2019Co-Authors: Siyu Chen, Yuezhong Wen, Hui Chen, Zunwei Chen, Wei-ping LiuAbstract:Plant fatty acids have indispensable physiological functions and nutritional value. However, the overuse of herbicides may cause phytotoxic disturbances of fatty acids in nontarget plants while spraying for weeds. Evidence has shown that the herbicide Dichlorprop can inhibit the activity of acetyl-CoA carboxylase (ACCase), a key enzyme involved in fatty acid synthesis. However, the enantioselective phytotoxic effects of Dichlorprop enantiomers ((R)-Dichlorprop and (S)-Dichlorprop) on fatty acids and their related mechanisms remain unclear. To solve this issue, the enantioselective phytotoxicity of Dichlorprop in the model plant species Arabidopsis thaliana (A. thaliana) with a focus on fatty acids was evaluated for the first time. The results indicated a significant difference in enantioselectivity and that exposure to (R)-Dichlorprop can cause marked fatty acid disturbances in nontarget plant species. Specifically, (R)-Dichlorprop decreased the content of three fatty acids by more than 50% by inhibiting the activity of ACCase. In addition, increased malondialdehyde (MDA) and lipid hydroperoxides (LOOHs) contents and membrane permeability reflected herbicide-induced lipid peroxidation, which decreased the unsaturation of fatty acids in membranes and further influenced membrane composition and function. Moreover, an increased level of glutathione peroxidase (GPX) and cytochrome P450 (CYP450) reflected a plant stress-induced response. To summarize, fatty acids represent a new perspective for evaluating the toxicity of chiral pesticides, contributing to a better understanding of the enantioselective phytotoxicity and mechanisms of Dichlorprop, and providing evidence for herbicide security and risk assessments.
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Dichlorprop induced structural changes of lhcii chiral macroaggregates associated with enantioselective toxicity to scnedesmus obliquus
Aquatic Toxicology, 2019Co-Authors: Hui Chen, Zunwei Chen, Chensi Shen, Babar Aijaz Ali, Yuezhong WenAbstract:Abstract The enantioselective toxic mechanisms of chiral herbicides in photosynthetic organisms are closely related to the production of reactive oxygen species (ROS) production, however, there are few reports on how the enantioselective production of ROS can be triggered. In suboptimal conditions, photosynthesis is one of the most important processes in the production of ROS, especially in the process of light utilization and electron transfer. In this study, we investigated the interactions between chiral herbicide Dichlorprop (DCPP) enantiomers and the chiral macroaggregates of the photosynthetic light-harvesting chlorophyll a/b pigment-protein complexes (LHCII) in Scenedesmus obliquus, which is of great significance in capturing and utilizing sun light, and also in dissipating the excess excitation energy. The results of the circular dichroism indicated that DCPP induced the structural changes of the LHCII chiral macroaggregates in an enantioselective manner and that the (R)-DCPP treated-group showed a bigger change accompanied by a changed enantioselective dissipation of the excitation energy. The excitation energy was excessed in DCPP treated-groups and the degree of excess was enantioselective and the detrimental non-chemical energy triggered the enantioselective production of ROS, that induced the enantioselective toxicity to green algae S. obliquus. Overall, this study has identified that how the enantioselective production of ROS can be triggered in chloroplasts; this can help to reveal the enantioselective mechanisms of chiral herbicides to photosynthetic organisms.
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enantioselective phytotoxicity of Dichlorprop to arabidopsis thaliana the effect of cytochrome p450 enzymes and the role of fe
Environmental Science & Technology, 2017Co-Authors: Zunwei Chen, Yuezhong Wen, Hui Chen, Jia Wang, Wei-ping LiuAbstract:The ecotoxicology effects of chiral herbicides have long been recognized and have drawn increasing attention. The toxic mechanisms of herbicides in plants are involved in production of reactive oxygen species (ROS) and cause damage to target enzymes, but the relationship between these two factors in the enantioselectivity of chiral herbicides has rarely been investigated. Furthermore, even though cytochromes P450 enzymes (CYP450s) have been related to the phytotoxicity of herbicides, their roles in the enantioselectivity of chiral herbicides have yet to be explored. To solve this puzzle, the CYP450s suicide inhibitor 1-aminobenzotriazole (ABT) was added to an exposure system made from Dichlorprop (DCPP) enantiomers in the model plant Arabidopsis thaliana. The results indicated that different phytotoxicities of DCPP enantiomers by causing oxidative stress and acetyl-CoA carboxylase (ACCase) damage were observed in the presence and the absence of ABT. The addition of ABT decreased the toxicity of (R)-DCPP but was not significantly affected that of (S)-DCPP, resulting in smaller differences between enantiomers. Furthermore, profound differences were also observed in Fe uptake and distribution, exhibiting different distribution patterns in A. thaliana leaves exposed to DCPP and ABT, which helped bridge the relationship between ROS production and target enzyme ACCase damage through the function of CYP450s. These results offer an opportunity for a more-comprehensive understanding of chiral herbicide action mechanism and provide basic evidence for risk assessments of chiral herbicides in the environment.
Christian W Thorstensen - One of the best experts on this subject based on the ideXlab platform.
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sorption of bentazone Dichlorprop mcpa and propiconazole in reference soils from norway
Journal of Environmental Quality, 2001Co-Authors: Christian W Thorstensen, Olav Lode, Ole Martin Eklo, Agnethe ChristiansenAbstract:Sorption-desorption kinetic and isotherm studies were performed by the batch equilibrium technique in three Norwegian soils. The soils were a fine sandy loam, a loam, and a soil of highly decomposed organic material. Two commercially formulations were used, Triagran-P and Tilt, containing either a mixture of bentazone [3-isopropyl-1H-2, 1,3-benzothiadiazin-4(3H)-one 2,2-dioxide], Dichlorprop [(R)-2-(2, 4-dichlorophenoxy)-propionic acid], and MCPA [(4-chloro-2-methylphenoxy)acetic acid], or propiconazole [(±)1-(2-(2,4-dichlorophenyl))-4-propyl-1,3-dioxolan-2-ylmethyl)-1H-1,2,4-triazole] alone. Sorption-desorption equilibrium occurred within 10 h for all pesticides. The Freundlich isotherms indicated nonlinear sorption of bentazone, Dichlorprop, MCPA, and propiconazole. For all pesticides the highest Freundlich adsorption coefficient (K F ) values were in the soil with highest organic content and lowest pH. For the fine sandy loam and loam, which are representative Norwegian agricultural soils, the results indicate that bentazone, Dichlorprop, and MCPA are mobile with K F values ranging from 0.07 to 1.50 mg t-1/n kg -1 L 1/n . Propiconazole is much less mobile with K F values ranging from 27.00 to 36.02 mg 1 1/n kg -1 L 1/n in the agricultural soils.
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determination of bentazone Dichlorprop and mcpa in different soils by sodium hydroxide extraction in combination with solid phase preconcentration
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Christian W Thorstensen, Agnethe ChristiansenAbstract:A method for the extraction of bentazone, Dichlorprop, and MCPA in three selected Norwegian soils of different textures is described. Initially three different extraction methods were tested on one soil type. All methods gave recoveries >80% for the pesticide mixture, but extraction with sodium hydroxide in combination with solid-phase preconcentration was used for further recovery tests with soils of different properties spiked at four herbicide concentration levels (0.001−10 μg/g of wet soil). The method was rapid and easy and required a minimum of organic solvents. The recoveries were in the range of 82−109, 80−123, and 45−91% for the soils containing 1.4 (Hole), 2.5 (Kroer), and 37.8% (Froland) organic carbon, respectively. Limits of quantification using GC-MS were 0.0003 μg/g of wet soil for bentazone and 0.0001 μg/g of wet soil for both Dichlorprop and MCPA. Keywords: Soil extraction; solid-phase extraction; phenoxy acids; bentazone
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laboratory degradation studies of bentazone Dichlorprop mcpa and propiconazole in norwegian soils
Journal of Environmental Quality, 2001Co-Authors: Christian W Thorstensen, Olav LodeAbstract:: Laboratory degradation studies were performed in Norwegian soils using two commercial formulations (Tilt and Triagran-P) containing either propiconazole alone or a combination of bentazone, Dichlorprop, and MCPA. These soils included a fine sandy loam from Hole and a loam from Kroer, both of which are representative of Norwegian agricultural soils. The third soil was a highly decomposed organic material from the Froland forest. A fourth soil from the Skuterud watershed was used only for propiconazole degradation. After 84 d, less than 0.1% of the initial MCPA concentration remained in all three selected soils. For Dichlorprop, the same results were found for the fine sandy loam and the organic-rich soil, but in the loam, 26% of the initial concentration remained. After 84 d, less than 0.1% of the initial concentration of bentazone remained in the organic-rich soil, but in the loam and the fine sandy loam 52 and 69% remained, respectively. Propiconazole was shown to be different from the other pesticides by its persistence. Amounts of initial concentration remaining varied from 40, 70, and 82% in the reference soils after 84 d for the organic-rich soil, fine sandy loam, and loam, respectively. The organic-rich soil showed the highest capacity to decompose all four pesticides. The results from the agricultural soils and the Skuterud watershed showed that the persistence of propiconazole was high. Pesticide degradation was approximated to first-order kinetics. Slow rates of degradation, where more than 50% of the pesticide remained in the soil after the 84-d duration of the experiment, did not fit well with first-order kinetics.
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development of a solid phase extraction method for phenoxy acids and bentazone in water and comparison to a liquid liquid extraction method
Journal of Agricultural and Food Chemistry, 2000Co-Authors: Christian W Thorstensen, Olav Lode, Agnethe ChristiansenAbstract:A rapid solid-phase extraction (SPE) method was developed for the determination of bentazone and the phenoxy acids 2,4-D, Dichlorprop, MCPA, and mecoprop in Norwegian environmental water samples. Cartridges with a high-capacity cross-linked polystyrene-based polymer were used for off-line preconcentration. The effects of elution solvent, elution volume, sample volume, sorbent mass, pH, and flow rate on the recoveries of the pesticides were investigated using HPLC. Average recovery of >90% was achieved with 500 mg sorbents using 2 mL of methanol with 5% NH3 as elution solvent. The recoveries were independent of sample pH in the tested range of pH 1−7. Using a sample volume of 200 mL, the limits of determination for the phenoxy acids and bentazone are 0.02 μg/L. Sample volumes up to 2000 mL at a flow rate of 60 mL/min could be handled without any loss of analytes, which makes it possible to lower the limits of determination. The SPE method was compared to a routinely used liquid−liquid extraction method. Th...