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Mi H, Zhou Q, Li G, Tao Y, Wang A, Wang P, Yang T, Zhu J, Li Y, Wei C, Liu S. Molecular responses reveal that two glutathione S-transferase CsGSTU8s contribute to detoxification of glyphosate in tea plants (Camellia sinensis). Int J Biol Macromol 2024; 277:134304. [PMID: 39084443 DOI: 10.1016/j.ijbiomac.2024.134304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 07/27/2024] [Accepted: 07/28/2024] [Indexed: 08/02/2024]
Abstract
Tea plant (Camellia sinensis) is an important economical crop that frequently suffers from various herbicides, especially glyphosate. However, the molecular responses and regulatory mechanisms of glyphosate stress in tea plants remain poorly understood. Here, we reported a transcriptome dataset and identified large number of differentially expressed genes (DEGs) under glyphosate exposure. Next, two glutathione S-transferase genes (CsGSTU8-1 and CsGSTU8-2) that upregulated significantly were screened as candidate genes. Tissue-specific expression patterns showed that both CsGSTU8-1 and CsGSTU8-2 had extremely high expression levels in the roots and were predominantly localized in the nucleus and plasma membrane based on subcellular localization. Both were significantly upregulated at different time points under various stressors, including drought, cold, salt, pathogen infections, and SA treatments. An enzymatic activity assay showed that CsGSTU8-1 catalyzes the conjugation of glutathione with 2,4-dinitrochlorobenzene (CDNB). Functional analysis in yeast verified that the two genes significantly contributed to the detoxification of glyphosate, and CsGSTU8-1 had a stronger role in detoxification than CsGSTU8-2. Taken together, these findings provide insights into the molecular responses of tea plants to glyphosate and the functions of CsGSTU8s in glyphosate detoxification, which can be used as a promising genetic resource for improving herbicide resistance in tea cultivars.
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Affiliation(s)
- Hongzhi Mi
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Qianqian Zhou
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Guoqiang Li
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Yongning Tao
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Aoni Wang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Pengke Wang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Tianyuan Yang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Junyan Zhu
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Yeyun Li
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China
| | - Chaoling Wei
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China.
| | - Shengrui Liu
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, West 130 Changjiang Road, Hefei, Anhui 230036, People's Republic of China.
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Jin W, Xie K, Tang W, Yang Y, Zhang J, Yu X, Lu Y. Comparative metabolomics and transcriptomics provide new insights into florpyrauxifen-benzyl resistance in Echinochloa glabrescens. FRONTIERS IN PLANT SCIENCE 2024; 15:1392460. [PMID: 39022606 PMCID: PMC11253777 DOI: 10.3389/fpls.2024.1392460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 06/10/2024] [Indexed: 07/20/2024]
Abstract
Echinochloa glabrescens Munro ex Hook. f. is a weed of the genus Echinocloa (Echinocloa spp.) that occurs frequently in paddy fields, causing serious harm to rice production. Florpyrauxifen-benzyl (FPB) is a foliar-applied herbicide used to control Echinocloa spp. in paddy fields. However, in recent years, with the widespread use of FPB in rice production, FPB-resistant barnyard grasses have been reported. Here, we identified an FPB-resistant E. glabrescens population with a resistance index (RI) of 10.65 and conducted a comparative analysis using untargeted metabolomics and transcriptomics to investigate the differences between an FPB-resistant E. glabrescens population and a susceptible E. glabrescens population after treatment with the recommended field dose of FPB. Our results showed that the FPB-resistant E. glabrescens had 115 differentially accumulated metabolites (DAMs; 65 up-regulated and 50 down-regulated) and 6397 differentially expressed genes (DEGs; 65 up-regulated and 50 down-regulated) compared to the susceptible E. glabrescens. The analysis of DAMs and DEGs revealed that DAMs were significantly enriched in Glutathione metabolism, Arginine and proline metabolism, and Zeatin biosynthesis pathways, while DEGs were mainly enriched in carbon fixation in photosynthetic organisms, photosynthesis, cyanoamino acid metabolism and glutathione metabolism, etc. The glutathione metabolism pathway was found to be significantly enriched for both DEGs and DAMs. Within this pathway, the metabolites (spermine) and genes (GSTU8, GSTU18, GSTF1) may play a pivotal role in the resistance mechanism of FPB-resistant E. glabrescens. Furthermore, we demonstrated the presence of GST-mediated metabolic resistance in an FPB-resistant E. glabrescens population by using NBD-Cl. Overall, our study provides new insights into the underlying mechanisms of E. glabrescens resistance to FPB through a comparative analysis of untargeted metabolomics and transcriptomics. Additionally, we identified the GST-mediated metabolic resistance in an FPB-resistant E. glabrescens population, and screened for three candidate genes (GSTU8, GSTU18, GSTF1), which has significant implications for improving the weed management efficacy of FPB in rice production and guiding judicious herbicide usage.
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Affiliation(s)
| | | | | | | | | | - Xiaoyue Yu
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
| | - Yongliang Lu
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
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Peniche-Pavía HA, Guzmán TJ, Magaña-Cerino JM, Gurrola-Díaz CM, Tiessen A. Maize Flavonoid Biosynthesis, Regulation, and Human Health Relevance: A Review. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27165166. [PMID: 36014406 PMCID: PMC9413827 DOI: 10.3390/molecules27165166] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/01/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022]
Abstract
Maize is one of the most important crops for human and animal consumption and contains a chemical arsenal essential for survival: flavonoids. Moreover, flavonoids are well known for their beneficial effects on human health. In this review, we decided to organize the information about maize flavonoids into three sections. In the first section, we include updated information about the enzymatic pathway of maize flavonoids. We describe a total of twenty-one genes for the flavonoid pathway of maize. The first three genes participate in the general phenylpropanoid pathway. Four genes are common biosynthetic early genes for flavonoids, and fourteen are specific genes for the flavonoid subgroups, the anthocyanins, and flavone C-glycosides. The second section explains the tissue accumulation and regulation of flavonoids by environmental factors affecting the expression of the MYB-bHLH-WD40 (MBW) transcriptional complex. The study of transcription factors of the MBW complex is fundamental for understanding how the flavonoid profiles generate a palette of colors in the plant tissues. Finally, we also include an update of the biological activities of C3G, the major maize anthocyanin, including anticancer, antidiabetic, and antioxidant effects, among others. This review intends to disclose and integrate the existing knowledge regarding maize flavonoid pigmentation and its relevance in the human health sector.
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Affiliation(s)
- Héctor A. Peniche-Pavía
- Departamento de Bioquímica y Biotecnología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Irapuato, Libramiento Norte Km. 9.6, Irapuato 36824, Guanajuato, Mexico
| | - Tereso J. Guzmán
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 48, 48149 Münster, Germany
| | - Jesús M. Magaña-Cerino
- División Académica de Ciencias de la Salud, Centro de Investigación y Posgrado, Universidad Juárez Autónoma de Tabasco, Av. Gregorio Méndez Magaña 2838-A, Col. Tamulté de las Barrancas, Villahermosa 86150, Tabasco, Mexico
| | - Carmen M. Gurrola-Díaz
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Instituto de Investigación en Enfermedades Crónico Degenerativas, Instituto Transdisciplinar de Investigación e Innovación en Salud, Universidad de Guadalajara, C. Sierra Mojada 950. Col. Independencia, Guadalajara 44340, Jalisco, Mexico
- Correspondence: ; Tel.: +52-33-10585200 (ext. 33930)
| | - Axel Tiessen
- Departamento de Bioquímica y Biotecnología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Irapuato, Libramiento Norte Km. 9.6, Irapuato 36824, Guanajuato, Mexico
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Liu T, Zhang X. Comparative transcriptome and metabolome analysis reveal glutathione metabolic network and functional genes underlying blue and red-light mediation in maize seedling leaf. BMC PLANT BIOLOGY 2021; 21:593. [PMID: 34906076 PMCID: PMC8670197 DOI: 10.1186/s12870-021-03376-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/30/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Light quality severely affects biosynthesis and metabolism-associated process of glutathione. However, the role of specific light is still unclear on the glutathione metabolism. In this article, comparatively transcriptome and metabolome methods are used to fully understand the blue and red-light conditions working on the glutathione metabolism in maize seedling leaf. RESULTS There are 20 differently expressed genes and 4 differently expressed metabolites in KEGG pathway of glutathione metabolism. Among them, 12 genes belong to the glutathione S-transferase family, 3 genes belong to the ascorbate peroxidase gene family and 2 genes belong to the ribonucleoside-diphosphate reductase gene family. Three genes, G6PD, SPDS1, and GPX1 belong to the gene family of glucose 6-phosphate dehydrogenase, spermidine synthase, and glutathione peroxidase, respectively. Four differently expressed metabolites are identified. Three of them, Glutathione disulfide, Glutathione, and l-γ-Glutamyl-L-amino acid are decreased while L-Glutamate is increased. In addition, Through PPI analysis, two annotated genes gst16 and DAAT, and 3 unidentified genes 100381533, pco105094 and umc2770, identified as RPP13-like3, BCAT-like1and GMPS, were obtained. By the analysis of protein sequence and PPI network, we predict that pco105094 and umc2770 were involved in the GSSG-GSH and AsA-GSH cycle in the network of glutathione metabolism. CONCLUSIONS Compared to red light, blue light remarkably changed the transcription signal transduction and metabolism of glutathione metabolism. Differently expressed genes and metabolic mapped to the glutathione metabolism signaling pathways. In total, we obtained three unidentified genes, and two of them were predicted in current glutathione metabolism network. This result will contribute to the research of glutathione metabolism of maize.
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Affiliation(s)
- Tiedong Liu
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
| | - Xiwen Zhang
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002 Fujian China
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Ren X, Ma L, Wang N, Zhou R, Wu J, Xie X, Zhang H, Liu D, Ma X, Dang C, Kang H, Zhou Z. Antioxidant Gene Signature Impacts the Immune Infiltration and Predicts the Prognosis of Kidney Renal Clear Cell Carcinoma. Front Genet 2021; 12:721252. [PMID: 34490047 PMCID: PMC8416991 DOI: 10.3389/fgene.2021.721252] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 07/30/2021] [Indexed: 01/05/2023] Open
Abstract
Background: Oxidative stress is related to oncogenic transformation in kidney renal clear cell carcinoma (KIRC). We intended to identify a prognostic antioxidant gene signature and investigate its relationship with immune infiltration in KIRC. Methods: With the support of The Cancer Genome Atlas (TCGA) database, we researched the gene expression and clinical data of KIRC patients. Antioxidant related genes with significant differences in expression between KIRC and normal samples were then identified. Through univariate and multivariate Cox analysis, a prognostic gene model was established and all patients were divided into high- and low-risk subgroups. Single sample gene set enrichment analysis was adopted to analyze the immune infiltration, HLA expression, and immune checkpoint genes in different risk groups. Finally, the prognostic nomogram model was established and evaluated. Results: We identified six antioxidant genes significantly correlated with the outcome of KIRC patients as independent predictors, namely DPEP1 (HR = 0.97, P < 0.05), GSTM3 (HR = 0.97, P < 0.05), IYD (HR = 0.33, P < 0.05), KDM3B (HR = 0.96, P < 0.05), PRDX2 (HR = 0.99, P < 0.05), and PRXL2A (HR = 0.96, P < 0.05). The high- and low-risk subgroups of KIRC patients were grouped according to the six-gene signature. Patients with higher risk scores had poorer prognosis, more advanced grade and stage, and more abundance of M0 macrophages, regulatory T cells, and follicular helper T cells. There were statistically significant differences in HLA and checkpoint gene expression between the two risk subgroups. The performance of the nomogram was favorable (concordance index = 0.766) and reliably predicted the 3-year (AUC = 0.792) and 5-year (AUC = 0.766) survival of patients with KIRC. Conclusion: The novel six antioxidant related gene signature could effectively forecast the prognosis of patients with KIRC, supply insights into the interaction between cellular antioxidant mechanisms and cancer, and is an innovative tool for selecting potential patients and targets for immunotherapy.
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Affiliation(s)
- Xueting Ren
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Li Ma
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Nan Wang
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ruina Zhou
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jianhua Wu
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xin Xie
- Department of Surgical Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Hao Zhang
- Department of Surgical Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Di Liu
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xiaobin Ma
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Chengxue Dang
- Department of Surgical Oncology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Huafeng Kang
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Zhangjian Zhou
- Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Rangani G, Noguera M, Salas-Perez R, Benedetti L, Roma-Burgos N. Mechanism of Resistance to S-metolachlor in Palmer amaranth. FRONTIERS IN PLANT SCIENCE 2021; 12:652581. [PMID: 33777086 PMCID: PMC7994610 DOI: 10.3389/fpls.2021.652581] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/19/2021] [Indexed: 05/13/2023]
Abstract
Herbicides are major tools for effective weed management. The evolution of resistance to herbicides in weedy species, especially contributed by non-target-site-based resistance (NTSR) is a worrisome issue in crop production globally. Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) is one of the extremely difficult weeds in southern US crop production. In this study, we present the level and molecular basis of resistance to the chloroacetamide herbicide, S-metolachlor, in six field-evolved A. palmeri populations that had survivors at the recommended field-dose (1.1 kg ai ha-1). These samples were collected in 2014 and 2015. The level of resistance was determined in dose-response assays. The effective dose for 50% control (ED50) of the susceptible population was 27 g ai ha-1, whereas the ED50 of the resistant populations ranged from 88 to 785 g ai ha-1. Therefore, A. palmeri resistance to S-metolachlor evolved in Arkansas as early as 2014. Metabolic-inhibitor and molecular assays indicated NTSR in these populations, mainly driven by GSTs. To understand the mechanism of resistance, selected candidate genes were analyzed in leaves and roots of survivors (with 1 × S-metolachlor). Expression analysis of the candidate genes showed that the primary site of S-metolachlor detoxification in A. palmeri is in the roots. Two GST genes, ApGSTU19 and ApGSTF8 were constitutively highly expressed in roots of all plants across all resistant populations tested. The expression of both GSTs increased further in survivors after treatment with S-metolachlor. The induction level of ApGSTF2 and ApGSTF2like by S-metolachlor differed among resistant populations. Overall, higher expression of ApGSTU19, ApGSTF8, ApGSTF2, and ApGSTF2like, which would lead to higher GST activity in roots, was strongly associated with the resistant phenotype. Phylogenetic relationship and analysis of substrate binding site of candidate genes suggested functional similarities with known metolachlor-detoxifying GSTs, effecting metabolic resistance to S-metolachlor in A. palmeri. Resistance is achieved by elevated baseline expression of these genes and further induction by S-metolachlor in resistant plants.
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Affiliation(s)
- Gulab Rangani
- Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Matheus Noguera
- Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Reiofeli Salas-Perez
- Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Lariza Benedetti
- Crop Protection Graduate Program (Programa de Pós-Graduação em Fitossanidade), Federal University of Pelotas (Universidade Federal de Pelotas), Pelotas, Brazil
| | - Nilda Roma-Burgos
- Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR, United States
- *Correspondence: Nilda Roma-Burgos
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Wang S, Yang J, You L, Dai M, Zhao Y. GSTM3 Function and Polymorphism in Cancer: Emerging but Promising. Cancer Manag Res 2020; 12:10377-10388. [PMID: 33116892 PMCID: PMC7585806 DOI: 10.2147/cmar.s272467] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/23/2020] [Indexed: 12/17/2022] Open
Abstract
Cancer is a major cause of human mortality; however, the molecular mechanisms and proteomic biomarkers that cause tumor progression in malignant tumors are either unknown or only partially revealed. Glutathione S-transferases mu3 (GSTM3), which belongs to a family of xenobiotic detoxifying phase II enzymes, is associated with carcinogen detoxification and the metabolism of exogenous electrophilic substances. It has been reported that GSTM3 has different polymorphisms in various tumor cells and regulates tumorigenesis, cell invasion, metastasis, chemoresistance, and oxidative stress. Deep research into the regulatory mechanisms involved in disorders of GSTM3 expression and the function of GSTM3 in different cancers may facilitate improvements in cancer prevention and targeted therapy. The combination of GSTM3 with other family members can regulate the carcinogenesis and susceptibility to different cancers in humans. GSTM3 also regulates the reactive oxygen species (ROS) and participates in oxidative stress-mediated pathology. Here, we provide a general introduction to GSTM3 in order to better understand the role of GSTM3 in cancer.
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Affiliation(s)
- Shunda Wang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Jinshou Yang
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Lei You
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Menghua Dai
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Yupei Zhao
- Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
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Thiam A, Salazar R. Fenton-based electrochemical degradation of metolachlor in aqueous solution by means of BDD and Pt electrodes: influencing factors and reaction pathways. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:2580-2591. [PMID: 30474812 DOI: 10.1007/s11356-018-3768-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
This work explores the role of electrode material and the oxidation ability of electrochemical advanced oxidation processes (EAOPs), such as electro-oxidation (EO) with or without H2O2 production, electro-Fenton (EF), and UVA photoelectron-Fenton (PEF), in the degradation of metolachlor. The performance of the EAOPs using Boron-doped diamond (BDD) or Pt as anode has been compared from the analysis of decay kinetics, mineralization profile, and energy consumption using small undivided batch cell. Metolachlor concentration always decays following a pseudo-first-order kinetics. Using the Pt anode, none of the processes reaches 30% mineralization, including PEF. In contrast, the BDD anode showed a higher mineralization rate allowing almost total mineralization in PEF due to the synergetic action of UVA light and oxidant hydroxyl radicals formed in the bulk from Fenton's reaction, as well as in the BDD, which has large reactivity to oxidize the pollutants. The increase in current density and decrease in metolachlor concentration accelerated the mineralization in PEF, although lower current efficiency and higher energy consumption was obtained. The GC-MS and HPLC analysis allowed the identification of up to 17 aromatics intermediates and 7 short-chain carboxylic acids. Finally, a reaction pathway for metolachlor mineralization by EAOPs is proposed. PEF with BDD allowed total removal of the herbicide in real water matrix and a high mineralization (83.82%).
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Affiliation(s)
- Abdoulaye Thiam
- Programa Institucional de Fomento a la I+D+i, Universidad Tecnológica Metropolitana, Ignacio Valdivieso 2409, P.O. Box 8940577, San Joaquín, Santiago, Chile.
| | - Ricardo Salazar
- Laboratorio de Electroquímica del MedioAmbiente, LEQMA, Facultad de Química y Biología, Universidad de Santiago de Chile, USACh, Casilla 40, Correo, 33, Santiago, Chile
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