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Yu Q, He A, Shi D, Sheng GD. Translocation versus ion trapping in the root uptake of 2,4-dichlorophenol by wheat seedlings. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:56392-56400. [PMID: 34050911 DOI: 10.1007/s11356-021-14627-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
Understanding of the plant uptake of ionizable organic compounds is critical to the evaluation of crop contamination, plant protection, and phytoremediation. This study investigated the time-dependent uptake of 2,4-dichlorophenol (DCP) by intact wheat seedling roots and subsequent translocation to shoots at pH 5.0 and 8.0. Sorption of DCP by cut roots and shoots at these two pHs was conducted to provide the uptake limits and the Donnan charge. For comparison, sorption was also conducted for 1,3-dichlorobenzene (DCB), a nonionizable compound having a structure similar to that of DCP. The DCB sorption isotherms were linear and independent of pH, yielding a consistent log Klip of 3.56 with both roots and shoots, reflective of the essential dominant role of lipids in plant partition uptake. Whereas the DCP sorption also showed a linear isotherm at pH 5.0 with log Klip = 2.88, the sorption at pH 8.0 was nonlinear with a concave downward shape, especially at low concentrations. With live wheat seedlings, the DCB uptake by roots and the DCB translocation to shoots rapidly approached a steady state, showing no obvious pH effect. On the DCP uptake by live plants, there was a rapid attainment of a steady state in roots at pH 5.0 coupled with a retarded transport to shoots due presumably to the polarity of DCP. At pH 8.0, the root uptake of DCP was comparatively slower and the translocation to shoots was completely inhibited due presumably to DCP ionization. At high pH, DCP was supposedly accumulated in an ionized form in root cells via an ion-trapping mechanism.
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Affiliation(s)
- Qi Yu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Anfei He
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Dongjin Shi
- School of the Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - G Daniel Sheng
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China.
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Koba Ucun O, Montazeri B, Arslan Alaton İ, Ölmez Hanci T. Treatment of industrial contaminants with zero-valent iron- and zero-valent aluminium-activated persulfate: a case study with 3,5-dichlorophenol and 2,4-dichloroaniline. Turk J Chem 2021; 45:269-281. [PMID: 34104043 PMCID: PMC8164209 DOI: 10.3906/kim-1911-60] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/03/2021] [Indexed: 11/11/2022] Open
Abstract
Zero-valent iron (ZVI)- and zero-valent aluminium (ZVA)-activated persulfate (PS) oxidation procedure was applied to remove the industrial pollutants 3,5-dichlorophenol (3,5-DCP; 12.27 µM) and 2,4-dichloroaniline (2,4-DCA; 12.34 µM) from aqueous solutions. The effects of PS concentration and pH were investigated to optimize heterogeneous treatment systems. Negligible removals were obtained for both pollutants by individual applications of nanoparticles (1 g/L) and PS (1.00 mM). PS activation with ZVI resulted in 59% (1.00 mM PS; 1 g/L ZVI; pH 5.0; 120 min) and 100% (0.75 mM PS; 1 g/L ZVI; pH 5.0; 80 min) 3,5-DCP and 2,4-DCA removals, respectively. The ZVA/PS treatment system gave rise to only 31% 3,5-DCP (1.00 mM PS; 1 g/L ZVA; pH 3.0; 120 min) and 47% 2,4-DCA (0.25 mM PS; 1 g/L ZVA; pH 3.0; 120 min) removals. The pH decreases from 5.0 to 3.0 and from 3.0 to 1.5 enhanced contaminant removals for ZVI/PS and ZVA/PS treatments, respectively. Pollutant removal rates were in correlation with the consumption rates of the oxidants. Metal ion (Al, Fe) release increased in the presence of PS and with decreasing pH.
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Affiliation(s)
- Olga Koba Ucun
- Department of Environmental Engineering, School of Civil Engineering, İstanbul Technical University, İstanbul Turkey
| | - Bahareh Montazeri
- Department of Environmental Engineering, School of Civil Engineering, İstanbul Technical University, İstanbul Turkey
| | - İdil Arslan Alaton
- Department of Environmental Engineering, School of Civil Engineering, İstanbul Technical University, İstanbul Turkey
| | - Tuğba Ölmez Hanci
- Department of Environmental Engineering, School of Civil Engineering, İstanbul Technical University, İstanbul Turkey
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Skelton JJ, Simpson DM, Peterson MA, Riechers DE. Biokinetic Analysis and Metabolic Fate of 2,4-D in 2,4-D-Resistant Soybean (Glycine max). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:5847-5859. [PMID: 28650629 DOI: 10.1021/acs.jafc.7b00796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The Enlist weed control system allows the use of 2,4-D in soybean but slight necrosis in treated leaves may be observed in the field. The objectives of this research were to measure and compare uptake, translocation, and metabolism of 2,4-D in Enlist (E, resistant) and non-AAD-12 transformed (NT, sensitive) soybeans. The adjuvant from the Enlist Duo herbicide formulation (ADJ) increased 2,4-D uptake (36%) and displayed the fastest rate of uptake (U50= 0.2 h) among treatments. E soybean demonstrated a faster rate of 2,4-D metabolism (M50= 0.2 h) compared to NT soybean, but glyphosate did not affect 2,4-D metabolism. Metabolites of 2,4-D in E soybean were qualitatively different than NT. Applying 2,4-D-ethylhexyl ester instead of 2,4-D choline (a quaternary ammonium salt) eliminated visual injury to E soybean, likely due to the time required for initial de-esterification and bioactivation. Excessive 2,4-D acid concentrations in E soybean resulting from ADJ-increased uptake may significantly contribute to foliar injury.
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Affiliation(s)
- Joshua J Skelton
- Department of Crop Sciences, University of Illinois , Urbana, Illinois 61801, United States
| | - David M Simpson
- Dow AgroSciences LLC , Indianapolis, Indiana 46268, United States
| | - Mark A Peterson
- Dow AgroSciences LLC , Indianapolis, Indiana 46268, United States
| | - Dean E Riechers
- Department of Crop Sciences, University of Illinois , Urbana, Illinois 61801, United States
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Rodriguez-Hernandez MC, García De la-Cruz RF, Leyva E, Navarro-Tovar G. Typha latifolia as potential phytoremediator of 2,4-dichlorophenol: Analysis of tolerance, uptake and possible transformation processes. CHEMOSPHERE 2017; 173:190-198. [PMID: 28110008 DOI: 10.1016/j.chemosphere.2016.12.043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/17/2016] [Accepted: 12/09/2016] [Indexed: 06/06/2023]
Abstract
2,4-Dichlorophenol (2,4-DCP) is considered a priority pollutant due to its high toxicity. Therefore, it is urgent to develop technologies for the disposal of this pollutant. Various remediation processes have been proposed for the elimination of 2,4-DCP in contaminated water, however, most of them involve high costs of operation and maintenance. This study aimed to determine the capacity of remediation of 2,4-DCP in water by Typha latifolia L. wild plants. For that, the tolerance, removal, accumulation and biotransformation of 2,4-DCP by T. latifolia were investigated. The plants were exposed to 2,4-DCP solutions with a concentration range from 1.5 to 300 mgL-1 for 10 days. They exhibited a reduction in chlorophyll levels and growth rate when 2,4-DCP solutions were ≥30 mgL-1 and ≥50 mgL-1, respectively. The removal of contaminant was dose-depended, being 99.7% at 1.5-3 mgL-1, 59-70% at 10-70 mgL-1 and 35-42% at 100-300 mgL-1 of 2,4-DCP in the solution. Studies indicated that 2,4-DCP was mainly accumulated in root tissue rather than in shoot tissue. Acid hydrolysis of biomass extracts suggests 2,4-DCP bioconjugates formation in root tissue as a response mechanism. Additionally, an increment in glutathione S-transferase (GST) activity could indicate a 2,4-DCP conjugation with glutathione as a detoxification mechanism of T. latifolia.
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Affiliation(s)
- M C Rodriguez-Hernandez
- Plant Biochemistry Laboratory, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6 Zona Universitaria, 78210, San Luis Potosí, Mexico
| | - R F García De la-Cruz
- Plant Biochemistry Laboratory, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6 Zona Universitaria, 78210, San Luis Potosí, Mexico.
| | - E Leyva
- Organic Synthesis Laboratory, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6 Zona Universitaria, 78210, San Luis Potosí, Mexico
| | - G Navarro-Tovar
- Recombinant Biopharmaceuticals Laboratory, Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 6 Zona Universitaria, 78210, San Luis Potosí, Mexico
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Zhou X, Rotondaro SL, Ma M, Rosser SW, Olberding EL, Wendelburg BM, Adelfinskaya YA, Balcer JL, Blewett TC, Clements B. Metabolism and Residues of 2,4-Dichlorophenoxyacetic Acid in DAS-40278-9 Maize (Zea mays) Transformed with Aryloxyalkanoate Dioxygenase-1 Gene. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:7438-7444. [PMID: 27617353 DOI: 10.1021/acs.jafc.6b03104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
DAS-40278-9 maize, which is developed by Dow AgroSciences, has been genetically modified to express the aryloxyalkanoate dioxygenase-1 (AAD-1) protein and is tolerant to phenoxy auxin herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D). To understand the metabolic route and residue distribution of 2,4-D in DAS-40278-9 maize, a metabolism study was conducted with 14C-radiolabeled 2,4-D applied at the maximum seasonal rate. Plants were grown in boxes outdoors. Forage and mature grain, cobs, and stover were collected for analysis. The metabolism study showed that 2,4-D was metabolized to 2,4-dichlorophenol (2,4-DCP), which was then rapidly conjugated with glucose. Field-scale residue studies with 2,4-D applied at the maximum seasonal rate were conducted at 25 sites in the U.S. and Canada to measure the residues of 2,4-D and free and conjugated 2,4-DCP in mature forage, grain, and stover. Residues of 2,4-D were not detectable in the majority of the grain samples and averaged <1.0 and <1.5 μg/g in forage and stover, respectively. Free plus conjugated 2,4-DCP was not observed in grain and averaged <1.0 μg/g in forage and stover.
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Affiliation(s)
- Xiao Zhou
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Sandra L Rotondaro
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Mingming Ma
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Steve W Rosser
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Ed L Olberding
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Brian M Wendelburg
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Yelena A Adelfinskaya
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Jesse L Balcer
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - T Craig Blewett
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Bruce Clements
- Dow AgroSciences, LLC , 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
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Pascal-Lorber S, Létondor C, Liber Y, Jamin EL, Laurent F. Chlordecone Transfer and Distribution in Maize Shoots. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:409-415. [PMID: 26701746 DOI: 10.1021/acs.jafc.5b05115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chlordecone (CLD) is a persistent organic pollutant (POP) that was mainly used as an insecticide against banana weevils in the French West Indies (1972-1993). Transfer of CLD via the food chain is now the major mechanism for exposure of the population to CLD. The uptake and the transfer of CLD were investigated in shoots of maize, a C4 model plant growing under tropical climates, to estimate the exposure of livestock via feed. Maize plants were grown on soils contaminated with [(14)C]CLD under controlled conditions. The greatest part of the radioactivity was associated with roots, nearly 95%, but CLD was detected in whole shoots, concentrations in old leaves being higher than those in young ones. CLD was thus transferred from the base toward the plant top, forming an acropetal gradient of contaminant. In contrast, results evidenced the existence of a basipetal gradient of CLD concentration within leaves whose extremities accumulated larger amounts of CLD because of evapotranspiration localization. Extractable residues accounted for two-thirds of total residues both in roots and in shoots. This study highlighted the fact that the distribution of CLD contamination within grasses resulted from a conjunction between the age and evapotranspiration rate of tissues. CLD accumulation in fodder may be the main route of exposure for livestock.
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Affiliation(s)
| | - Clarisse Létondor
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS , Toulouse, France
- ADEME , F-49000 Angers, France
| | - Yohan Liber
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS , Toulouse, France
| | - Emilien L Jamin
- INRA , UMR1331, Toxalim, Research Centre in Food Toxicology, 180 chemin de Tournefeuille, BP 93173, F-31027 Toulouse Cedex 3, France
- Université de Toulouse, INPT, UPS, UMR1331, F-31062 Toulouse, France
| | - François Laurent
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS , Toulouse, France
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Xu ZS, Lin YQ, Xu J, Zhu B, Zhao W, Peng RH, Yao QH. Selective Detoxification of Phenols by Pichia pastoris and Arabidopsis thaliana Heterologously Expressing the PtUGT72B1 from Populus trichocarpa. PLoS One 2013; 8:e66878. [PMID: 23840543 PMCID: PMC3694158 DOI: 10.1371/journal.pone.0066878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 05/10/2013] [Indexed: 11/20/2022] Open
Abstract
Phenols are present in the environment and commonly in contact with humans and animals because of their wide applications in many industries. In a previous study, we reported that uridine diphosphate-glucose-dependent glucosyltransferase PtUGT72B1 from Populus trichocarpa has high activity in detoxifying trichlorophenol by conjugating glucose. In this study, more experiments were performed to determine the substrate specificity of PtUGT72B1 towards phenolic compounds. Among seven phenols tested, three were glucosylated by PtUGT72B1 including phenol, hydroquinone, and catechol. Transgenic Arabidopsis plants expressing the enzyme PtUGT72B1 showed higher resistance to hydroquinone and catechol but more sensitivity to phenol than wild type plants. Transgenic Pichia pastoris expressing PtUGT72B1 showed enhanced resistance to all three phenols. Compared with wild type Arabidopsis plants, transgenic Arabidopsis plants showed higher removal efficiencies and exported more glucosides of phenol, phenyl β-D-glucopyranoside, to the medium after cultured with the three phenols. Protein extracts from transgenic Arabidopsis plants showed enhanced conjugating activity towards phenol, hydroquinone and catechol. PtUGT72B1 showed much higher expression level in Pichia pastoris than in Arabidopsis plants. Kinetic analysis of the PtUGT72B1 was also performed.
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Affiliation(s)
- Zhi-Sheng Xu
- College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Ya-Qiu Lin
- College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Jing Xu
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Bo Zhu
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Wei Zhao
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Ri-He Peng
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Quan-Hong Yao
- College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Agricultural Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, China
- * E-mail:
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Pascal-Lorber S, Despoux S, Jamin EL, Canlet C, Cravedi JP, Laurent F. Metabolic fate of 2,4-dichlorophenol and related plant residues in rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:1728-36. [PMID: 22276578 DOI: 10.1021/jf203666k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
This study compared the metabolic fate of [(14)C]-DCP, [(14)C]-residues from radish plants, and purified [(14)C]-DCP-(acetyl)glucose following oral administration in rats. A rapid excretion of radioactivity in urine occurred for [(14)C]-DCP, [(14)C]-DCP-(acetyl)glucose, and soluble residues, 69, 85, and 69% within 48 h, respectively. Radio-HPLC profiles of 0-24 h urine from rats fed [(14)C]-DCP and [(14)C]-DCP-(acetyl)glucose were close and qualitatively similar to those obtained from plant residues. No trace of native plant residues was detected under the study conditions. The structures of the two major peaks were identified by MS as the glucuronide and the sulfate conjugates of DCP. The characterization of a dehydrated glucuronide conjugate by MS and NMR of DCP was unusual. In contrast to soluble residues, bound residues were mainly excreted in feces, 90% within 48 h, whereas total residues were eliminated in both urine and feces. For total residues, the radioactivity in feces was higher than expected from the percentage of soluble and bound residues in radish plants. This result highlighted that less absorption took place when residues were present in the plant matrix as compared to plant-free residues and DCP.
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Affiliation(s)
- Sophie Pascal-Lorber
- Université de Toulouse, INP, UPS, EcoLab, ENSAT, F-31000 Castanet Tolosan, France.
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Pascal-Lorber S, Alsayeda H, Jouanin I, Debrauwer L, Canlet C, Laurent F. Metabolic fate of [¹⁴C]diuron and [¹⁴C]linuron in wheat (Triticum aestivum) and radish (Raphanus sativus). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:10935-10944. [PMID: 20886880 DOI: 10.1021/jf101937x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Metabolism of xenobiotics in plants usually occurs in three phases, phase I (primary metabolism), phase II (conjugation processes), and phase III (storage). The uptake and metabolism of [(14)C]diuron and [(14)C]linuron were investigated in wheat and radish. Seeds were sown in quartz sand and irrigated with a nutrient solution of either radioactive herbicide. Plants were harvested after two weeks, and metabolites were extracted and then analyzed by radio-reverse-high-performance liquid chromatography (HPLC). Uptake of the two molecules was higher in radish compared to wheat. Translocation of parent compounds and related metabolites from roots to aerial plant parts was important, especially for radish. A large proportion of extractable residues were found in radish whereas nonextractable residues amounted to 30% in wheat, mainly associated with roots. Chemical structure of metabolites was thereafter identified by acid, alkaline, and enzymatic hydrolyses followed by electrospray ionization mass spectrometry (ESI-MS) and proton nuclear magnetic resonance spectroscopy ((1)H NMR). This study highlighted the presence of diuron and linuron metabolites conjugated to sugars in addition to N-demethylation and N-demethoxylation products.
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Affiliation(s)
- Sophie Pascal-Lorber
- INRA, UMR1089 Xénobiotiques, 180 Chemin de Tournefeuille, F-31000 Toulouse, France
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Michałowicz J, Posmyk M, Duda W. Chlorophenols induce lipid peroxidation and change antioxidant parameters in the leaves of wheat (Triticum aestivum L.). JOURNAL OF PLANT PHYSIOLOGY 2009; 166:559-568. [PMID: 19027988 DOI: 10.1016/j.jplph.2008.09.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 08/12/2008] [Accepted: 09/04/2008] [Indexed: 05/27/2023]
Abstract
In this work, changes in superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (POD) activity were determined in the leaves of wheat (Triticum aestivum L.) exposed to 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP). We analyzed the content of free phenols, the level of lipid peroxidation, and also the oxidation of dihydrorhodamine 123 by 2,4-DCP and PCP. Chlorophenols were spiked to soil in concentrations of 0.5 and 5.0 mg kg(-1). Plant seeds were raised in plastic pots containing soil at a temperature of 25 degrees C with a 16-h photoperiod and irradiance of 250 micromol m(-2) s(-1). The leaves were harvested on the third, sixth and twelfth days of the experiment. The inhibition of SOD activity in the leaves of wheat was observed for 2,4-DCP and PCP. 2,4-DCP and PCP induced changes in CAT activity with a stronger effect for PCP. The compounds markedly increased guaiacol POD activity during 12d of the exposition of wheat to their action. The increase in free phenol content was observed both for 2,4-DCP and PCP. Chlorophenols also induced a powerful lipid peroxidation process between the third and sixth days of the experiment. A higher concentration of chlorophenols used in our study induced greater changes in all of the investigated parameters. 2,4-DCP and PCP oxidized the fluorescent probe - dihydrorhodamine 123 - in the concentrations of 5 and 1 ppm, respectively, and the addition of magnesium ions enhanced the oxidative capacity of the examined xenobiotics.
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Gandia-Herrero F, Lorenz A, Larson T, Graham IA, Bowles DJ, Rylott EL, Bruce NC. Detoxification of the explosive 2,4,6-trinitrotoluene in Arabidopsis: discovery of bifunctional O- and C-glucosyltransferases. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 56:963-74. [PMID: 18702669 DOI: 10.1111/j.1365-313x.2008.03653.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants, as predominantly sessile organisms, have evolved complex detoxification pathways to deal with a diverse range of toxic chemicals. The elasticity of this stress response system additionally enables them to tackle relatively recently produced, novel, synthetic pollutants. One such compound is the explosive 2,4,6-trinitrotoluene (TNT). Large areas of soil and groundwater are contaminated with TNT, which is both highly toxic and recalcitrant to degradation, and persists in the environment for decades. Although TNT is phytotoxic, plants are able to tolerate low levels of the compound. To identify the genes involved in this detoxification process, we used microarray analysis and then subsequently characterized seven uridine diphosphate (UDP) glycosyltransferases (UGTs) from Arabidopsis thaliana (Arabidopsis). Six of the recombinantly expressed UGTs conjugated the TNT-transformation products 2- and 4-hydroxylaminodinitrotoulene, exhibiting individual bias for either the 2- or the 4-isomer. For both 2- and 4-hydroxylaminodinitrotoulene substrates, two monoglucose conjugate products, confirmed by HPLC-MS-MS, were observed. Further analysis indicated that these were conjugated by either an O- or C-glucosidic bond. The other major compounds in TNT metabolism, aminodinitrotoluenes, were also conjugated by the UGTs, but to a lesser extent. These conjugates were also identified in extracts and media from Arabidopsis plants grown in liquid culture containing TNT. Overexpression of two of these UGTs, 743B4 and 73C1, in Arabidopsis resulted in increases in conjugate production, and enhanced root growth in 74B4 overexpression seedlings. Our results show that UGTs play an integral role in the biochemical mechanism of TNT detoxification by plants.
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Pascal-Lorber S, Despoux S, Rathahao E, Canlet C, Debrauwer L, Laurent F. Metabolic fate of [14C] chlorophenols in radish (Raphanus sativus), lettuce (Lactuca sativa), and spinach (Spinacia oleracea). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:8461-9. [PMID: 18763782 DOI: 10.1021/jf8016354] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Chlorophenols are potentially harmful pollutants that are found in numerous natural and agricultural systems. Plants are a sink for xenobiotics, which occur either intentionally or not, as they are unable to eliminate them although they generally metabolize them into less toxic compounds. The metabolic fate of [ (14)C] 4-chlorophenol (4-CP), [ (14)C] 2,4-dichlorophenol (2,4-DCP), and [ (14)C] 2,4,5-trichlorophenol (2,4,5-TCP) was investigated in lettuce, spinach, and radish to locate putative toxic metabolites that could become bioavailable to food chains. Radish plants were grown on sand for four weeks before roots were dipped in a solution of radiolabeled chlorophenol. The leaves of six-week old lettuce and spinach were treated. Three weeks after treatments, metabolites from edible plant parts were extracted and analyzed by high performance liquid chromatography (HPLC) and characterized by mass spectrometry (MS), and nuclear magnetic resonance spectroscopy (NMR). Characterization of compounds highlighted the presence of complex glycosides. Upon hydrolysis in the digestive tract of animals or humans, these conjugates could return to the toxic parent compound, and this should be kept in mind for registration studies.
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Affiliation(s)
- Sophie Pascal-Lorber
- INRA, UMR1089 Xenobiotiques, 180 ch. de Tournefeuille, BP3, F-31931 Toulouse, Cedex 9, France.
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Petroutsos D, Katapodis P, Samiotaki M, Panayotou G, Kekos D. Detoxification of 2,4-dichlorophenol by the marine microalga Tetraselmis marina. PHYTOCHEMISTRY 2008; 69:707-714. [PMID: 17936864 DOI: 10.1016/j.phytochem.2007.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 08/30/2007] [Accepted: 09/01/2007] [Indexed: 05/25/2023]
Abstract
Xenobiotic chlorinated phenols have been found in fresh and marine waters and are toxic to many aquatic organisms. Metabolism of 2,4-dichlorophenol (2,4-DCP) in the marine microalga Tetraselmis marina was studied. The microalga removed more than 1mM of 2,4-DCP in a 2l photobioreactor over a 6 day period. Two metabolites, more polar than 2,4-DCP, were detected in the growth medium by reverse phase HPLC and their concentrations increased at the expense of 2,4-DCP. The metabolites were isolated by a C8 HPLC column and identified as 2,4-dichlorophenyl-beta-d-glucopyranoside (DCPG) and 2,4-dichlorophenyl-beta-d-(6-O-malonyl)-glucopyranoside (DCPGM) by electrospray ionization-mass spectrometric analysis in a negative ion mode. The molecular structures of 2,4-DCPG and 2,4-CPGM were further confirmed by enzymatic and alkaline hydrolyses. Thus, it was concluded that the major pathway of 2,4-DCP metabolism in T. marina involves an initial conjugation of 2,4-DCP to glucose to form 2,4-dichlorophenyl-beta-d-glucopyranoside, followed by acylation of the glucoconjugate to form 2,4-dichlorophenyl-beta-d-(6-O-malonyl)-glucopyranoside. The microalga ability to detoxify dichlorophenol congeners other than 2,4-DCP was also investigated. This work provides the first evidence that microalgae can use a combined glucosyl and malonyl transfer to detoxify xenobiotics such as dichlorophenols.
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Affiliation(s)
- Dimitris Petroutsos
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9, Iroon Polytechniou Str, Zografou Campus, Athens 15780, Greece
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Petroutsos D, Wang J, Katapodis P, Kekos D, Sommerfeld M, Hu Q. Toxicity and metabolism of p-chlorophenol in the marine microalga Tetraselmis marina. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2007; 85:192-201. [PMID: 17950940 DOI: 10.1016/j.aquatox.2007.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 09/04/2007] [Accepted: 09/05/2007] [Indexed: 05/25/2023]
Abstract
Toxicity and metabolism of para-chlorophenol (p-CP) in the marine microalga Tetraselmis marina have been studied. The inhibition constant EC(50) for p-CP was 272+/-17 microM (34.8+/-2.2 mg L(-1)) under the experimental conditions. Two metabolites were detected in the growth medium in the presence of p-CP by reverse phase HPLC and their concentrations increased at the expense of p-CP. The two metabolites, which were found to be more polar than p-CP, were isolated by a C18 column. They were identified as p-chlorophenyl-beta-D-glucopyranoside (p-CPG) and p-chlorophenyl-beta-D-(6-O-malonyl)-glucopyranoside (p-CPGM) by electrospray ionization-mass spectrometric analysis in a negative ion mode. The molecular structures of p-CPG and p-CPGM were further confirmed by enzymatic and alkaline hydrolyses. Treatment with beta-glucosidase released free p-CP and glucose from p-CPG, whereas p-CPGM was completely resistant. Alkaline hydrolysis completely cleaved the esteric bond of the malonylated glucoconjugate and yielded p-CPG and malonic acid. It was concluded that the pathway of p-CP metabolism in T. marina involves an initial conjugation of p-CP to glucose to form p-chlorophenyl-beta-d-glucopyranoside, followed by acylation of the glucoconjugate to form p-chlorophenyl-beta-D-(6-O-malonyl)-glucopyranoside. The metabolism of p-CP in T. marina was mainly driven by photosynthesis, and to a lesser extent by anabolic metabolism in the dark. Accordingly, the detoxification rate under light was about seven times higher than in the darkness. This work provides the first evidence that microalgae can adopt a combined glucosyl transfer and malonyl transfer process as a survival strategy for detoxification of such xenobiotics as p-CP.
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Affiliation(s)
- Dimitris Petroutsos
- Department of Applied Biological Sciences, Arizona State University Polytechnic Campus, 7001 E. Williams Field Road, Mesa, AZ 85212, USA
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Laurent F, Canlet C, Debrauwer L, Pascal-Lorber S. Metabolic fate of [(14)C]-2,4-dichlorophenol in tobacco cell suspension cultures. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2007; 26:2299-307. [PMID: 17941740 DOI: 10.1897/07-036r.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Accepted: 05/31/2007] [Indexed: 05/25/2023]
Abstract
In plant tissues, xenobiotics often are conjugated with natural constituents such as sugars, amino acids, glutathione, and malonic acid. Usually, conjugation processes result in a decrease in the reactivity and toxicity of xenobiotics by increasing the water solubility and polarity of conjugates, and reducing their mobility. Due to their lack of an efficient excretory system, xenobiotic conjugates finally are sequestered in plant storage compartments or cell vacuoles, or are integrated as bound residues in cell walls. Chlorophenols are potentially harmful pollutants that are found in numerous natural and agricultural systems. We studied the metabolic fate of 2,4-dichlorophenol (DCP) in cell-suspension cultures of tobacco (Nicotiana tabacum L.). After a standard metabolism experiment, 48 h of incubation with a [U-phenyl-(14)C]-DCP solution, aqueous extracts of cell suspension cultures were analyzed by high-performance liquid chromatography (HPLC). Metabolites then were isolated and their chemical structures determined by enzymatic and chemical hydrolyses, electrospray ionization-mass spectrometry in negative mode (ESI-NI), and (1)H nuclear magnetic resonance analyses. The main terminal metabolites identified were DCP-glycoside conjugates, DCP-(6-O-malonyl)-glucoside, DCP-(6-O-acetyl)-glucoside, and their precursor, DCP-glucoside. More unusual and complex DCP conjugates such as an alpha(1-->6)-glucosyl-pentose and a triglycoside containing a glucuronic acid were further characterized. All the metabolites identified were complex glycoside conjugates. However, these conjugates still may be a source of DCP in hydrolysis reactions caused by microorganisms in the environment or in the digestive tract of animals and humans. Removal of xenobiotics by glycoside conjugation thus may result in underestimation of the risk associated with toxic compounds like DCP in the environment or in the food chain.
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Affiliation(s)
- Francois Laurent
- Institut National de la Recherche Agronomique, Unite Mixte de Recherches 1089 Xénobiotiques, F-31000 Toulouse, France.
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Laurent F, Debrauwer L, Pascal-Lorber S. Metabolism of [14C]-2,4-dichlorophenol in edible plants. PEST MANAGEMENT SCIENCE 2006; 62:558-64. [PMID: 16628540 DOI: 10.1002/ps.1213] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Several 2,4-dichlorophenoxyacetic acid (2,4-D)-sensitive plants have been modified by genetic engineering with tfdA gene to acquire 2,4-D tolerance. The expression product of this gene degrades 2,4-D to 2,4-dichlorophenol (DCP), which is less phytotoxic but could cause a problem of food safety. After a comparison of 2,4-D and DCP metabolism in transgenic 2,4-D-tolerant and wild cotton (Gossypium hirsutum L.), a direct study of DCP metabolism in edible plants was performed. After petiolar uptake of a [U-phenyl-(14)C]-DCP solution followed by a 48 h water chase, aqueous extracts were analysed by high-performance liquid chromatography. Metabolites were thereafter isolated and their structural identities were determined by enzymatic and chemical hydrolyses and mass spectrometry analyses. The metabolic fate of DCP was equivalent to 2,4-D metabolism in transgenic 2,4-D-tolerant cotton. In addition, DCP metabolism was similar in transgenic and wild cotton. The major terminal metabolites were DCP-saccharide conjugates in all species, essentially DCP-(6-O-malonyl)-glucoside or its precursor DCP-glucose. The significance of this metabolic pathway with regard to food safety is discussed.
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Affiliation(s)
- François Laurent
- INRA, UMR Xénobiotiques, 180 Ch. de Tournefeuille, BP3, F-31931 Toulouse Cedex 9, France.
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Brazier-Hicks M, Edwards R. Functional importance of the family 1 glucosyltransferase UGT72B1 in the metabolism of xenobiotics in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 42:556-66. [PMID: 15860014 DOI: 10.1111/j.1365-313x.2005.02398.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The Arabidopsis type 1 UDP-glucose-dependent glucosyltransferase UGT72B1 is highly active in conjugating the persistent pollutants 3,4-dichloroaniline (DCA) and 2,4,5-trichlorophenol (TCP). To determine its importance in detoxifying xenobiotics in planta, mutant plants where the respective gene has been disrupted by T-DNA insertion have been characterized. Extracts from the knockout ugt72B1 plants showed radically reduced conjugating activity towards DCA and TCP and the absence of immunodetectable UGT72B1 protein. In contrast, activities towards phenolic natural products were unaffected. When aseptic root cultures were fed [14C]-DCA, compared with wild types, the ugt72B1 plants showed a reduced rate of uptake of the xenobiotic and very little metabolism to soluble DCA-glucose or associated polar conjugates. Instead, the knockouts accumulated non-extractable radioactive residues, most probably associated with lignification. When the feeding studies were carried out with [14C]-TCP, rates and routes of metabolism were identical in the wild type and knockouts, with TCP-glucoside a major product in both cases. Similar differential effects on the metabolism of DCA and TCP were obtained in whole plant studies with wild type and ugt72B1 mutants, demonstrating that while UGT72B1 had a central role in metabolizing chloroanilines in Arabidopsis, additional UGTs could compensate for the conjugation of TCP in the knockout. TCP was equally toxic to wild type and ugt72B1 plants, while surprisingly, the knockouts were less sensitive to DCA. From this it was concluded that the glucosylation of DCA may not be as effective in xenobiotic detoxification as bound-residue formation.
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