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Bopp C, Bernet NM, Meyer F, Khan R, Robinson SL, Kohler HPE, Buller R, Hofstetter TB. Elucidating the Role of O 2 Uncoupling for the Adaptation of Bacterial Biodegradation Reactions Catalyzed by Rieske Oxygenases. ACS ENVIRONMENTAL AU 2024; 4:204-218. [PMID: 39035869 PMCID: PMC11258757 DOI: 10.1021/acsenvironau.4c00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 07/23/2024]
Abstract
Oxygenation of aromatic and aliphatic hydrocarbons by Rieske oxygenases is the initial step of various biodegradation pathways for environmental organic contaminants. Microorganisms carrying Rieske oxygenases are able to quickly adapt their substrate spectra to alternative carbon and energy sources that are structurally related to the original target substrate, yet the molecular events responsible for this rapid adaptation are not well understood. Here, we evaluated the hypothesis that reactive oxygen species (ROS) generated by unproductive activation of O2, the so-called O2 uncoupling, in the presence of the alternative substrate exert a selective pressure on the bacterium for increasing the oxygenation efficiency of Rieske oxygenases. To that end, we studied wild-type 2-nitrotoluene dioxygenase from Acidovorax sp. strain JS42 and five enzyme variants that have evolved from adaptive laboratory evolution experiments with 3- and 4-nitrotoluene as alternative growth substrates. The enzyme variants showed a substantially increased oxygenation efficiency toward the new target substrates concomitant with a reduction of ROS production, while mechanisms and kinetics of enzymatic O2 activation remained unchanged. Structural analyses and docking studies suggest that amino acid substitutions in enzyme variants occurred at residues lining both substrate and O2 transport tunnels, enabling tighter binding of the target substrates in the active site. Increased oxygenation efficiencies measured in vitro for the various enzyme (variant)-substrate combinations correlated linearly with in vivo changes in growth rates for evolved Acidovorax strains expressing the variants. Our data suggest that the selective pressure from oxidative stress toward more efficient oxygenation by Rieske oxygenases was most notable when O2 uncoupling exceeded 60%.
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Affiliation(s)
- Charlotte
E. Bopp
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Nora M. Bernet
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Fabian Meyer
- Competence
Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zürich University of Applied Sciences, 8820 Wädenswil, Switzerland
| | - Riyaz Khan
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Serina L. Robinson
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Hans-Peter E. Kohler
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Rebecca Buller
- Competence
Center for Biocatalysis, Institute of Chemistry and Biotechnology, Zürich University of Applied Sciences, 8820 Wädenswil, Switzerland
| | - Thomas B. Hofstetter
- Eawag,
Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
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2
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Ruan W, Peng Y, Liao R, Man Y, Tai Y, Tam NFY, Zhang L, Dai Y, Yang Y. Removal, transformation and ecological risk assessment of pesticide in rural wastewater by field-scale horizontal flow constructed wetlands of treated effluent. WATER RESEARCH 2024; 256:121568. [PMID: 38593607 DOI: 10.1016/j.watres.2024.121568] [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: 01/19/2024] [Revised: 03/26/2024] [Accepted: 04/02/2024] [Indexed: 04/11/2024]
Abstract
Constructed wetlands (CWs) are widely used in sewage treatment in rural areas, but there are only a few studies on field-scale CWs in treating wastewater-borne pesticides. In this study, the treatment and metabolic transformation of 29 pesticides in rural domestic sewage by 10 field-scale horizontal flow CWs (HF-CWs), each with a treatment scale of 36‒5000 m3/d and operated for 2‒10 years, in Guangzhou, Southern China was investigated. The risk of pesticides in treated effluent and main factors influencing such risk were evaluated. Results demonstrated that HF-CWs could remove pesticides in sewage and reduce their ecological risk in effluent, but the degree varied among types of pesticides. Herbicides had the highest mean removal rate (67.35 %) followed by insecticides (60.13 %), and the least was fungicides (53.22 %). In terms of single pesticide compounds, the mean removal rate of butachlor was the highest (73.32 %), then acetochlor (69.41 %), atrazine (68.28 %), metolachlor (58.40 %), and oxadixyl (53.28 %). The overall removal rates of targeted pesticides in each HF-CWs ranged from 11 %‒57 %, excluding two HF-CWs showing increases in pesticides in treated effluent. Residues of malathion, phorate, and endosulfan in effluent had high-risks (RQ > 5). The pesticide concentration in effluent was mainly affected by that in influent (P = 0.042), and source control was the key to reducing risk. The main metabolic pathways of pesticide in HF-CWs were oxidation, with hydroxyl group to carbonyl group or to form sulfones, the second pathways by hydrolysis, aerobic condition was conducive to the transformation of pesticides. Sulfones were generally more toxic than the metabolites produced by hydrolytic pathways. The present study provides a reference on pesticides for the purification performance improvement, long-term maintenance, and practical sustainable application of field-scale HF-CWs.
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Affiliation(s)
- Weifeng Ruan
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education, Guangzhou, China
| | - Yanqin Peng
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education, Guangzhou, China
| | - Ruomei Liao
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education, Guangzhou, China
| | - Ying Man
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; School of Chemistry and Environment, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Yiping Tai
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education, Guangzhou, China.
| | - Nora Fung-Yee Tam
- School of Science and Technology, The Hong Kong Metropolitan University, Ho Man Tin, Kowloon 999077, Hong Kong, China
| | - Longzhen Zhang
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China
| | - Yunv Dai
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education, Guangzhou, China
| | - Yang Yang
- Institute of Hydrobiology and Department of Ecology, Jinan University, Guangzhou 510632, China; Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education, Guangzhou, China.
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3
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Zhang M, Gao S, Pan K, Liu H, Li Q, Bai X, Zhu Q, Chen Z, Yan X, Hong Q. Functional analysis, diversity, and distribution of the ean cluster responsible for 17 β-estradiol degradation in sphingomonads. Appl Environ Microbiol 2024; 90:e0197423. [PMID: 38619269 PMCID: PMC11107178 DOI: 10.1128/aem.01974-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 03/20/2024] [Indexed: 04/16/2024] Open
Abstract
17β-estradiol (E2) is a natural endocrine disruptor that is frequently detected in surface and groundwater sources, thereby threatening ecosystems and human health. The newly isolated E2-degrading strain Sphingomonas colocasiae C3-2 can degrade E2 through both the 4,5-seco pathway and the 9,10-seco pathway; the former is the primary pathway supporting the growth of this strain and the latter is a branching pathway. The novel gene cluster ean was found to be responsible for E2 degradation through the 4,5-seco pathway, where E2 is converted to estrone (E1) by EanA, which belongs to the short-chain dehydrogenases/reductases (SDR) superfamily. A three-component oxygenase system (including the P450 monooxygenase EanB1, the small iron-sulfur protein ferredoxin EanB2, and the ferredoxin reductase EanB3) was responsible for hydroxylating E1 to 4-hydroxyestrone (4-OH-E1). The enzymatic assay showed that the proportion of the three components is critical for its function. The dioxygenase EanC catalyzes ring A cleavage of 4-OH-E1, and the oxidoreductase EanD is responsible for the decarboxylation of the ring A-cleavage product of 4-OH-E1. EanR, a TetR family transcriptional regulator, acts as a transcriptional repressor of the ean cluster. The ean cluster was also found in other reported E2-degrading sphingomonads. In addition, the novel two-component monooxygenase EanE1E2 can open ring B of 4-OH-E1 via the 9,10-seco pathway, but its encoding genes are not located within the ean cluster. These results refine research on genes involved in E2 degradation and enrich the understanding of the cleavages of ring A and ring B of E2.IMPORTANCESteroid estrogens have been detected in diverse environments, ranging from oceans and rivers to soils and groundwater, posing serious risks to both human health and ecological safety. The United States National Toxicology Program and the World Health Organization have both classified estrogens as Group 1 carcinogens. Several model organisms (proteobacteria) have established the 4,5-seco pathway for estrogen degradation. In this study, the newly isolated Sphingomonas colocasiae C3-2 could degrade E2 through both the 4,5-seco pathway and the 9,10-seco pathway. The novel gene cluster ean (including eanA, eanB1, eanC, and eanD) responsible for E2 degradation by the 4,5-seco pathway was identified; the novel two-component monooxygenase EanE1E2 can open ring B of 4-OH-E1 through the 9,10-seco pathway. The TetR family transcriptional regulator EanR acts as a transcriptional repressor of the ean cluster. The cluster ean was also found to be present in other reported E2-degrading sphingomonads, indicating the ubiquity of the E2 metabolism in the environment.
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Affiliation(s)
- Mingliang Zhang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Siyuan Gao
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Kaihua Pan
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Hongfei Liu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Qian Li
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Xuekun Bai
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Qian Zhu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Zeyou Chen
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, China
| | - Xin Yan
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Qing Hong
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
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4
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Liu H, Yang H, Yin X, Wang S, Fang S, Zhang H. A novel pbd gene cluster responsible for pyrrole and pyridine ring cleavage in Rhodococcus ruber A5. JOURNAL OF HAZARDOUS MATERIALS 2024; 464:132992. [PMID: 37976859 DOI: 10.1016/j.jhazmat.2023.132992] [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: 08/29/2023] [Revised: 10/23/2023] [Accepted: 11/10/2023] [Indexed: 11/19/2023]
Abstract
Pyridine and pyrrole, which are regarded as recalcitrant chemicals, are released into the environment as a result of industrial manufacturing processes, posing serious hazards to both the environment and human health. However, the pyrrole degradation mechanism and the pyridine-degrading gene in Rhodococcus are unknown. Herein, a highly efficient pyridine and pyrrole degradation strain Rhodococcus ruber A5 was isolated. Strain A5 completely degraded 1000 mg/L pyridine in a mineral salt medium within 24 h. The pyridine degradation of strain A5 was optimized using the BoxBehnken design. The optimum degradation conditions were found to be pH 7.15, temperature 28.06 ℃, and inoculation amount 1290.94 mg/L. The pbd gene clusters involved in pyridine degradation were discovered via proteomic analysis. The initial ring cleavage of pyridine and pyrrole in strain A5 was carried out by the two-component flavin-dependent monooxygenase PbdA/PbdE. The degradation pathways of pyridine and pyrrole were proposed by the identification of metabolites and comparisons of homologous genes. Additionally, homologous pbd gene clusters were found to exist in different bacterial genomes. Our study revealed the ring cleavage mechanisms of pyrrole and pyridine, and strain A5 was identified as a promising resource for pyridine bioremediation.
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Affiliation(s)
- Hongming Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu 241000, Anhui, PR China; Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu 241000, Anhui, PR China
| | - Hao Yang
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu 241000, Anhui, PR China; Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu 241000, Anhui, PR China
| | - Xiaye Yin
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu 241000, Anhui, PR China; Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu 241000, Anhui, PR China
| | - Siwen Wang
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu 241000, Anhui, PR China; Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu 241000, Anhui, PR China
| | - Shangping Fang
- School of Anesthesiology, Wannan Medical College, Wuhu 241002, Anhui, China
| | - Hao Zhang
- Key Laboratory of Metallurgical Emission Reduction and Comprehensive Utilization of Resources, Ministry of Education (Anhui University of Technology), Ma'anshan 243002, Anhui, China.
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5
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Liu C, Powell MM, Rao G, Britt RD, Rittle J. Bioinformatic Discovery of a Cambialistic Monooxygenase. J Am Chem Soc 2024; 146:1783-1788. [PMID: 38198693 PMCID: PMC10811679 DOI: 10.1021/jacs.3c12131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 01/12/2024]
Abstract
Dinuclear monooxygenases mediate challenging C-H bond oxidation reactions throughout nature. Many of these enzymes are presumed to exclusively utilize diiron cofactors. Herein we report the bioinformatic discovery of an orphan dinuclear monooxygenase that preferentially utilizes a heterobimetallic manganese-iron (Mn/Fe) cofactor to mediate an O2-dependent C-H bond hydroxylation reaction. Unlike the structurally similar Mn/Fe-dependent monooxygenase AibH2, the diiron form of this enzyme (SfbO) exhibits a nascent enzymatic activity. This behavior raises the possibility that many other dinuclear monooxygenases may be endowed with the capacity to harness cofactors with a variable metal content.
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Affiliation(s)
- Chang Liu
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Magan M. Powell
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
| | - Guodong Rao
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - R. David Britt
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Jonathan Rittle
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California 94720, United States
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6
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Hashemi B, Salehian H, Rezvani M, Soltani S. Soil parameters including organic matter affecting pretilachlor leaching in different paddy fields. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:9495-9505. [PMID: 37358715 DOI: 10.1007/s10653-023-01666-w] [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: 08/10/2022] [Accepted: 06/13/2023] [Indexed: 06/27/2023]
Abstract
Finding a method, which may indicate the contribution of soil parameters including organic matter, pH and clay to pretilachlor leaching (persistence) in the soil, with the use of a suitable indicator, which indicates pretilachlor presence in the soil is of significance. Accordingly, using undisturbed soil columns, four paddy fields (A, B, C, D) in the suburbs of Babol city (Mazandaran province, northern Iran) were sampled before the preparation and irrigation of the fields in April 2021. Soil samples were transferred into PVC pipes (divided into 2 cm layers) measuring 12 (height) × 10 cm (diameter), and were injected with pretilachlor at the recommended (1.75 L/ha) and high doses (3.5 L/ha). The surface layers of all fields had a higher concentration of pretilachlor and organic matter with the highest contribution to pretilachlor persistence followed by clay and pH. In the 0-4 cm depth, herbicide concertation was the lowest in field A (139 mg/kg) and the highest in field C (161 mg/kg). The corresponding values for organic matter were equal to 1.88 and 5.68%, respectively. The bioassay of rice (the indicator plant), with a significant correlation with chemical analysis results, indicated field A and field C had the pretilachlor infiltration of 6 and 4 cm, respectively. Accordingly, rice is a suitable plant indicator for measuring the presence of pretilachlor as examining its shoot length is a good criterion for bioassay. Additionally, changes in the amount of organic matter in different soil layers can be used to predict the leaching level of pretilachlor.
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Affiliation(s)
- Bahareh Hashemi
- Department of Agronomy, College of Agriculture and Natural Resources, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
| | - Hamid Salehian
- Department of Agronomy, College of Agriculture and Natural Resources, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran.
| | - Mohammad Rezvani
- Department of Agronomy, College of Agriculture and Natural Resources, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
| | - Saeid Soltani
- Department of Biology, College of Science, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Mazandaran, Iran
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7
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Runda ME, de Kok NAW, Schmidt S. Rieske Oxygenases and Other Ferredoxin-Dependent Enzymes: Electron Transfer Principles and Catalytic Capabilities. Chembiochem 2023; 24:e202300078. [PMID: 36964978 DOI: 10.1002/cbic.202300078] [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: 01/31/2023] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 03/27/2023]
Abstract
Enzymes that depend on sophisticated electron transfer via ferredoxins (Fds) exhibit outstanding catalytic capabilities, but despite decades of research, many of them are still not well understood or exploited for synthetic applications. This review aims to provide a general overview of the most important Fd-dependent enzymes and the electron transfer processes involved. While several examples are discussed, we focus in particular on the family of Rieske non-heme iron-dependent oxygenases (ROs). In addition to illustrating their electron transfer principles and catalytic potential, the current state of knowledge on structure-function relationships and the mode of interaction between the redox partner proteins is reviewed. Moreover, we highlight several key catalyzed transformations, but also take a deeper dive into their engineerability for biocatalytic applications. The overall findings from these case studies highlight the catalytic capabilities of these biocatalysts and could stimulate future interest in developing additional Fd-dependent enzyme classes for synthetic applications.
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Affiliation(s)
- Michael E Runda
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Niels A W de Kok
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Sandy Schmidt
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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Chen SF, Chen WJ, Huang Y, Wei M, Chang C. Insights into the metabolic pathways and biodegradation mechanisms of chloroacetamide herbicides. ENVIRONMENTAL RESEARCH 2023; 229:115918. [PMID: 37062473 DOI: 10.1016/j.envres.2023.115918] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/04/2023] [Accepted: 04/13/2023] [Indexed: 05/21/2023]
Abstract
Chloroacetamide herbicides are widely used around the world due to their high efficiency, resulting in increasing levels of their residues in the environment. Residual chloroacetamides and their metabolites have been frequently detected in soil, water and organisms and shown to have toxic effects on non-target organisms, posing a serious threat to the ecosystem. As such, rapid and efficient techniques that eliminate chloroacetamide residues from the ecosystem are urgently needed. Degradation of these herbicides in the environment mainly occurs through microbial metabolism. Microbial strains such as Acinetobacter baumannii DT, Bacillus altitudinis A16, Pseudomonas aeruginosa JD115, Sphingobium baderi DE-13, Catellibacterium caeni DCA-1, Stenotrophomonas acidaminiphila JS-1, Klebsiella variicola B2, and Paecilomyces marquandii can effectively degrade chloroacetamide herbicides. The degradation pathway of chloroacetamide herbicides in aerobic bacteria is mainly initiated by an N/C-dealkylation reaction, followed by aromatic ring hydroxylation and cleavage processes, whereas dechlorination is the initial reaction in anaerobic bacteria. The molecular mechanisms associated with bacterial degradation of chloroacetamide herbicides have been explored, with amidase, hydrolase, reductase, ferredoxin and cytochrome P450 oxygenase currently known to play a pivotal role in the catabolic pathways of chloroacetamides. The fungal pathway for the degradation of these herbicides is more complex with more diversified products, and the degradation enzymes and genes involved remain to be discovered. However, there are few reviews specifically summarizing the microbial degrading species and biochemical mechanisms of chloroacetamide herbicides. Here, we briefly summarize the latest progress resulting from research on microbial strain resources and enzymes involved in degradation of these herbicides and their corresponding genes. Furthermore, we explore the biochemical pathways and molecular mechanisms for biodegradation of chloroacetamide herbicides in depth, thereby providing a reference for further research on the bioremediation of such herbicides.
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Affiliation(s)
- Shao-Fang Chen
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Wen-Juan Chen
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Yaohua Huang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Ming Wei
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Changqing Chang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China; Integrative Microbiology Research Centre, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
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9
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Mahanta K, Bhattacharyya PN, Sharma AK, Rajkhowa D, Lesueur D, Verma H, Parit R, Deka J, Medhi BK, Kohli A. Residue and soil dissipation kinetics of chloroacetanilide herbicides on rice (Oryzae sativa L.) and assessing the impact on soil microbial parameters and enzyme activity. ENVIRONMENTAL MONITORING AND ASSESSMENT 2023; 195:910. [PMID: 37392291 DOI: 10.1007/s10661-023-11513-1] [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: 12/16/2022] [Accepted: 06/11/2023] [Indexed: 07/03/2023]
Abstract
The present investigation determines the persistence of herbicides like butachlor and pretilachlor in Indian soil, and their impact on soil biological properties including microbial biomass carbon (MBC), total microbial population numbers, and enzyme activities. Butachlor was degraded faster in autumn rice soil (t1/2 of 10-13 days) than in winter rice soil (half-life of 16-18 days). The t1/2 of pretilachlor in winter rice was 12-16 days. Regardless of the seasons under cultivation, no pesticide residue was detected in rice at harvest. Herbicides induced an initial decline (0-14th days after application) in MBC (averages of 332.7-478.4 g g-1 dry soil in autumn rice and 299.6-444.3 g g-1 dry soil in winter rice), microbial populations (averages of 6.4 cfu g-1 in autumn rice and 4.6 cfu g-1 in winter rice), and phosphatase (averages of 242.6-269.3 μg p-nitrophenol g-1 dry soil h-1 in autumn rice and 188.2-212.2 μg p-nitrophenol g-1 dry soil h-1 in winter rice). The application of herbicides favored dehydrogenase (averages of 123.1-156.7 g TPF g-1 dry soil in autumn and 126.7-151.1 g TPF g-1 dry soil in winter) and urease activities (averages of 279.0-340.4 g NH4 g-1 soil 2 h-1 in autumn and 226.7-296.5 g NH4 g-1 soil 2 h-1 in winter) in rice soil at 0-14th DAA. The study suggests that applications of butachlor and pretilachlor at the rates of 1000 g ha-1 and 750 g ha-1, respectively, to control the weeds in the transplanted rice fields do not have any negative impact on the harvested rice and associated soil environment.
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Affiliation(s)
- Kaberi Mahanta
- Assam Agricultural University, Jorhat 785 013, Assam, India
| | | | | | - Dipjyoti Rajkhowa
- ICAR Research Complex for NEH Region, Nagaland Centre, Nagaland, 797106, India
| | - Didier Lesueur
- Centre de Coopération Internationale en Recherche Agronomique pour le Développent (CIRAD), UMR Eco&Sols, Hanoi, Vietnam
- Eco & Sols, Université de Montpellier (UMR), CIRAD, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Institut de Recherche pour le Développement (IRD), 34060 Montpellier, Montpellier SupAgro, France
- Alliance of Biodiversity International and International Center for Tropical Agriculture (CIAT), Asia hub, Common Microbial Biotechnology Platform (CMBP), Hanoi, Vietnam
- School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment-Deakin University, Melbourne, VIC 3125, Australia
- Chinese Academy of Tropical Agricultural Sciences, Rubber Research Institute, Haikou, China
| | - Harendra Verma
- ICAR Research Complex for NEH Region, Nagaland Centre, Nagaland, 797106, India
| | - Rajat Parit
- Assam Agricultural University, Jorhat 785 013, Assam, India
| | - Jayanta Deka
- Assam Agricultural University, Jorhat 785 013, Assam, India
| | | | - Anshuman Kohli
- Bihar Agriculture University, Sabour 813210, Bihar, India
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10
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Cheng L, Wang L, Wang X, Ou Y, Liu H, Hou X, Yan L, Li X. The various effect of cow manure compost on the degradation of imazethapyr in different soil types. CHEMOSPHERE 2023:139325. [PMID: 37356585 DOI: 10.1016/j.chemosphere.2023.139325] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/15/2023] [Accepted: 06/23/2023] [Indexed: 06/27/2023]
Abstract
Adding compost to soil is an effective strategy to promote the degradation of organic pollutants and reduce ecological risks. However, the effect of compost on the degradation of imazethapyr (IMET) in different soil types is not clear. To address this issue, a pot experiment was conducted, and high-throughput sequencing and mass spectrometry technology were used to identify the influence of cow manure compost on the degradation efficiency of IMET in black soil and saline-alkali soil and the role of key microorganisms. The results showed that adding compost to black soil increased the degradation rate of IMET by 12.58% and shortened the half-life by 53.37%, while in saline-alkali soil, the degradation rate of IMET decreased by 6.99% with no significant change in the half-life. High-throughput sequencing results showed that adding cow manure compost (mass ratio of 4%) significantly increased the abundance of bacterial families capable of degrading organic pollutants in black soil, but had an inhibitory effect on this bacterial community in saline-alkali soil. Redundancy analysis (RDA) results showed that total organic carbon (TOC), alkali-hydrolyzable nitrogen (AN), ammonia nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) were the main factors driving microbial community variation. Mass spectrometry analysis indicated that IMET generated three metabolites during the degradation process. Sphingomonadaceae and Vicinamibacteraceae could accelerate the breaking of side-chain alkyl groups, while Chitinophagaceae could cause the rearrangement of the imidazole ring structure, gradually metabolizing IMET into small organic molecules. The application of appropriate cow manure compost can promote the development of IMET-degrading bacteria by adjusting the organic carbon and dissolved nitrogen content in black soil. In the future, the quantitative effects of organic fertilizer application on the IMET degradation process in different soil types should be further analyzed, and microbial isolation and purification should be used to enhance the ability of microorganisms to degrade herbicides.
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Affiliation(s)
- Lei Cheng
- College of Plant Protection, Jilin Agricultural University, Changchun, 130118, China; State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; Jilin Provincial Engineering Center of CWs Design in Cold Region & Beautiful Country Construction, Changchun, 130102, China
| | - Lixia Wang
- State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; Jilin Provincial Engineering Center of CWs Design in Cold Region & Beautiful Country Construction, Changchun, 130102, China
| | - Xinhong Wang
- College of Plant Protection, Jilin Agricultural University, Changchun, 130118, China.
| | - Yang Ou
- State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; Jilin Provincial Engineering Center of CWs Design in Cold Region & Beautiful Country Construction, Changchun, 130102, China.
| | - Huiping Liu
- College of Plant Protection, Jilin Agricultural University, Changchun, 130118, China; State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; Jilin Provincial Engineering Center of CWs Design in Cold Region & Beautiful Country Construction, Changchun, 130102, China
| | - Xia Hou
- College of Plant Protection, Jilin Agricultural University, Changchun, 130118, China; State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Liming Yan
- College of Plant Protection, Jilin Agricultural University, Changchun, 130118, China; State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Xinyi Li
- College of Plant Protection, Jilin Agricultural University, Changchun, 130118, China; State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
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11
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Quareshy M, Shanmugam M, Cameron AD, Bugg TDH, Chen Y. Characterisation of an unusual cysteine pair in the Rieske carnitine monooxygenase CntA catalytic site. FEBS J 2023; 290:2939-2953. [PMID: 36617384 PMCID: PMC10952381 DOI: 10.1111/febs.16722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 12/01/2022] [Accepted: 01/06/2023] [Indexed: 01/09/2023]
Abstract
Rieske monooxygenases undertake complex catalysis integral to marine, terrestrial and human gut-ecosystems. Group-I to -IV Rieske monooxygenases accept aromatic substrates and have well-characterised catalytic mechanisms. Nascent to our understanding are Group-V members catalysing the oxidation/breakdown of quaternary ammonium substrates. Phylogenetic analysis of Group V highlights a cysteine residue-pair adjacent to the mononuclear Fe active site with no established role. Following our elucidation of the carnitine monooxygenase CntA structure, we probed the function of the cysteine pair Cys206/Cys209. Utilising biochemical and biophysical techniques, we found the cysteine residues do not play a structural role nor influence the electron transfer pathway, but rather are used in a nonstoichiometric role to ensure the catalytic iron centre remains in an Fe(II) state.
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Affiliation(s)
| | | | | | | | - Yin Chen
- School of Life SciencesUniversity of WarwickCoventryUK
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12
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Ma Q, Meng N, Su J, Li Y, Gu J, Wang Y, Wang J, Qu Y, Zhao Z, Sun Y. Unraveling the skatole biodegradation process in an enrichment consortium using integrated omics and culture-dependent strategies. J Environ Sci (China) 2023; 127:688-699. [PMID: 36522097 DOI: 10.1016/j.jes.2022.06.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 06/17/2023]
Abstract
3-Methylindole (skatole) is regarded as one of the most offensive compounds in odor emission. Biodegradation is feasible for skatole removal but the functional species and genes responsible for skatole degradation remain enigmatic. In this study, an efficient aerobic skatole-degrading consortium was obtained. Rhodococcus and Pseudomonas were identified as the two major and active populations by integrated metagenomic and metatranscriptomic analyses. Bioinformatic analyses indicated that the skatole downstream degradation was mainly via the catechol pathway, and upstream degradation was likely catalyzed by the aromatic ring-hydroxylating oxygenase and flavin monooxygenase. Genome binning and gene analyses indicated that Pseudomonas, Pseudoclavibacter, and Raineyella should cooperate with Rhodococcus for the skatole degradation process. Moreover, a pure strain Rhodococcus sp. DMU1 was successfully obtained which could utilize skatole as the sole carbon source. Complete genome sequencing showed that strain DMU1 was the predominant population in the consortium. Further crude enzyme and RT-qPCR assays indicated that strain DMU1 degraded skatole through the catechol ortho-cleavage pathway. Collectively, our results suggested that synergistic degradation of skatole in the consortium should be performed by diverse bacteria with Rhodococcus as the primary degrader, and the degradation mainly proceeded via the catechol pathway.
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Affiliation(s)
- Qiao Ma
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China.
| | - Nan Meng
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Jiancheng Su
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Yujie Li
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Jiazheng Gu
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Yidi Wang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Jingwei Wang
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Yuanyuan Qu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zelong Zhao
- Liaoning Key Lab of Germplasm Improvement and Fine Seed Breeding of Marine Aquatic Animals, Liaoning Ocean and Fisheries Science Research Institute, Dalian 116023, China.
| | - Yeqing Sun
- Institute of Environmental Systems Biology, College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
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13
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Liu H, Liu S, Liu H, Liu M, Yin X, Lu P, Hong Q, Liu A, Wan R, Fang S. Revealing the driving synergistic degradation mechanism of Rhodococcus sp. B2 on the bioremediation of pretilachlor-contaminated soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159086. [PMID: 36179826 DOI: 10.1016/j.scitotenv.2022.159086] [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: 07/06/2022] [Revised: 09/15/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
The pretilachlor has been widely used worldwide and has contaminated the environment for many years. The environmental fate of pretilachlor and its residues removal from the contaminated environment have attracted great concern. Reportedly, pretilachlor could partly be transformed to HECDEPA by Rhodococcus sp. B2. However, the effects of pretilachlor on soil bacterial communities and its complete metabolic pathway remain unknown. Herein, we investigated the mechanism of driving synergistic degradation of pretilachlor by strain B2 in the soil. The results revealed that pretilachlor showed a negative effect on bacterial communities and caused significant variations in the community structure. Strain B2 showed the ability to remediate the pretilachlor-contaminated soils and network analysis revealed that it may drive the enrichment of potential pretilachlor-degrading bacteria from the soil. The soil pretilachlor degradation may be facilitated by the members of the keystone families Comamonadaceae, Caulobacteraceae, Rhodospirillaceae, Chitinophagaceae, and Sphingomonadaceae. Meanwhile, Sphingomonas sp. M6, a member of the Sphingomonadaceae family, has been isolated from the strain B2 inoculation sample soil. The co-culture, comprising strain M6 and B2, could synergistic degrade pretilachlor within 30 h, which is the highest degradation rate. Strain M6 could completely degrade the HECDEPA via CDEPA and DEA. In the soil, a comparable pretilachlor degradation pathway may exist. This study suggested that strain B2 had the potential to drive the remediation of pretilachlor-contaminated soils.
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Affiliation(s)
- Hongming Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China.
| | - Shiyan Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Huijun Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Mengna Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Xiaye Yin
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Peng Lu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Qing Hong
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Aimin Liu
- Anhui Provincial Key Laboratory of Molecular Enzymology and Mechanism of Major Diseases, College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Rui Wan
- School of Ecology and Environment, Anhui Normal University, South of Jiuhua Road, Wuhu, Anhui 241002, China.
| | - Shangping Fang
- School of Anesthesiology, Wannan Medical College, Wuhu, Anhui, China
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14
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Biodegradation of Alachlor by a Newly Isolated Bacterium: Degradation Pathway and Product Analysis. Processes (Basel) 2022. [DOI: 10.3390/pr10112256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl]acetamide] is a chloroacetanilide herbicide and has been widely used as a selective pre-emergent and post-emergent herbicide to control weeds and grass. Due to its wide usage, direct application on the ground, high solubility in water, and moderate persistence, alachlor and its metabolites have been detected in various environments. Therefore, there is an increasing concern about the environmental fate of alachlor and its metabolites. Microbial biodegradation is a main method of removal of alachlor in the natural environment. In this study, we isolated new alachlor degrading bacterium and proposed a novel alachlor-degrading pathway. The alachlor-degrading bacterial strain, GC-A6, was identified as Acinetobacter sp. using 16S rRNA gene sequence analysis. Acinetobacter sp. GC-A6 utilized alachlor as its sole carbon source and degraded 100 mg L−1 of alachlor within 48 h, which was the highest alachlor degradation efficiency. The degradation pathway of alachlor was studied using GC-MS analysis. Alachlor was initially degraded to 2-chloro-N-(2,6-diethylphenyl) acetamide, which was further degraded to 2,6-diethylaniline and 7-ethylindoline, respectively. 2,6-Diethylaniline was transformed into N-(2,6-diethylphenyl) formamide. N-(2,6-diethylphenyl) formamide was a first-reported intermediate during the degrading pathway of alachlor by single isolate.
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15
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Liu J, Zhao S, Wu N, Hu G, Qiu J, He J, Qiao W. Sulfate-Dependent Anaerobic Degradation of Herbicide Acetochlor by a Sulfate-Reducing Bacterium Cupidesulfovibrio sp. SRB-5. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:13340-13348. [PMID: 36198124 DOI: 10.1021/acs.jafc.2c03327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Acetochlor, an important chloroacetamide herbicide (CAAH) widely used in agriculture, has resulted in environmental contamination, especially of anoxic habitats. In this study, a sulfate-reducing bacterium, designated as SRB-5, was isolated from anaerobic activated sludge and was identified as Cupidesulfovibrio sp. This bacterium possesses a novel anaerobic pathway capable of degrading acetochlor. In this pathway, sulfate is first reduced to sulfide, which attacks the C-Cl bond of acetochlor and abiotically forms acetochlor-thioalcohol and dis-S-acetochlor. These further undergo microbial degradation, producing the intermediates acetochlor ethanesulfonic acid, 2-methyl-6-ethylaniline, and 2-ethylaniline. The degradation half-times of acetochlor (100 μM) by strain SRB-5 were 2.4 and 4.2 days in industrial wastewater and paddy sludge, respectively. Strain SRB-5 could also degrade alachlor, propisochlor, butachlor, pretilachlor, and metolachlor, and the degradation kinetics fit the pseudo-first-order kinetics equation. This work highlights the potential application of strain SRB-5 for the remediation of CAAHs-contaminated sites.
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Affiliation(s)
- Junwei Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Shiyu Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Ningning Wu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Gang Hu
- Laboratory Centre of Life Science, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Wenjing Qiao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
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16
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Bopp CE, Bernet NM, Kohler HPE, Hofstetter TB. Elucidating the Role of O 2 Uncoupling in the Oxidative Biodegradation of Organic Contaminants by Rieske Non-heme Iron Dioxygenases. ACS ENVIRONMENTAL AU 2022; 2:428-440. [PMID: 36164353 PMCID: PMC9502038 DOI: 10.1021/acsenvironau.2c00023] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Oxygenations of aromatic
soil and water contaminants with molecular
O2 catalyzed by Rieske dioxygenases are frequent initial
steps of biodegradation in natural and engineered environments. Many
of these non-heme ferrous iron enzymes are known to be involved in
contaminant metabolism, but the understanding of enzyme–substrate
interactions that lead to successful biodegradation is still elusive.
Here, we studied the mechanisms of O2 activation and substrate
hydroxylation of two nitroarene dioxygenases to evaluate enzyme- and
substrate-specific factors that determine the efficiency of oxygenated
product formation. Experiments in enzyme assays of 2-nitrotoluene
dioxygenase (2NTDO) and nitrobenzene dioxygenase (NBDO) with methyl-,
fluoro-, chloro-, and hydroxy-substituted nitroaromatic substrates
reveal that typically 20–100% of the enzyme’s activity
involves unproductive paths of O2 activation with generation
of reactive oxygen species through so-called O2 uncoupling.
The 18O and 13C kinetic isotope effects of O2 activation and nitroaromatic substrate hydroxylation, respectively,
suggest that O2 uncoupling occurs after generation of FeIII-(hydro)peroxo species in the catalytic cycle. While 2NTDO
hydroxylates ortho-substituted nitroaromatic substrates
more efficiently, NBDO favors meta-substituted, presumably
due to distinct active site residues of the two enzymes. Our data
implies, however, that the O2 uncoupling and hydroxylation
activity cannot be assessed from simple structure–reactivity
relationships. By quantifying O2 uncoupling by Rieske dioxygenases,
our work provides a mechanistic link between contaminant biodegradation,
the generation of reactive oxygen species, and possible adaptation
strategies of microorganisms to the exposure of new contaminants.
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Affiliation(s)
- Charlotte E. Bopp
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Nora M. Bernet
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Hans-Peter E. Kohler
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Thomas B. Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
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17
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The Novel Monooxygenase Gene dipD in the dip Gene Cluster of Alcaligenes faecalis JQ135 Is Essential for the Initial Catabolism of Dipicolinic Acid. Appl Environ Microbiol 2022; 88:e0036022. [PMID: 35766505 PMCID: PMC9317849 DOI: 10.1128/aem.00360-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Dipicolinic acid (DPA), an essential pyridine derivative biosynthesized in Bacillus spores, constitutes a major proportion of global biomass carbon pool. Alcaligenes faecalis strain JQ135 could catabolize DPA through the "3HDPA (3-hydroxydipicolinic acid) pathway." However, the genes involved in this 3HDPA pathway are still unknown. In this study, a dip gene cluster responsible for DPA degradation was cloned from strain JQ135. The expression of dip genes was induced by DPA and negatively regulated by DipR. A novel monooxygenase gene, dipD, was crucial for the initial hydroxylation of DPA into 3HDPA and proposed to encode the key catalytic component of the multicomponent DPA monooxygenase. The heme binding protein gene dipF, ferredoxin reductase gene dipG, and ferredoxin genes dipJ/dipK/dipL were also involved in the DPA hydroxylation and proposed to encode other components of the multicomponent DPA monooxygenase. The 18O2 stable isotope labeling experiments confirmed that the oxygen atom in the hydroxyl group of 3HDPA came from dioxygen molecule rather than water. The protein sequence of DipD exhibits no significant sequence similarities with known oxygenases, suggesting that DipD was a new member of oxygenase family. Moreover, bioinformatic survey suggested that the dip gene cluster was widely distributed in many Alpha-, Beta-, and Gammaproteobacteria, including soil bacteria, aquatic bacteria, and pathogens. This study provides new molecular insights into the catabolism of DPA in bacteria. IMPORTANCE Dipicolinic acid (DPA) is a natural pyridine derivative that serves as an essential component of the Bacillus spore. DPA accounts for 5 to 15% of the dry weight of spores. Due to the huge number of spores in the environment, DPA is also considered to be an important component of the global biomass carbon pool. DPA could be decomposed by microorganisms and enter the global carbon cycling; however, the underlying molecular mechanisms are rarely studied. In this study, a DPA catabolic gene cluster (dip) was cloned and found to be widespread in Alpha-, Beta-, and Gammaproteobacteria. The genes responsible for the initial hydroxylation of DPA to 3-hydroxyl-dipicolinic acid were investigated in Alcaligenes faecalis strain JQ135. The present study opens a door to elucidate the mechanism of DPA degradation and its possible role in DPA-based carbon biotransformation on earth.
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18
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The Novel Amidase PcnH Initiates the Degradation of Phenazine-1-Carboxamide in Sphingomonas histidinilytica DS-9. Appl Environ Microbiol 2022; 88:e0054322. [PMID: 35579476 PMCID: PMC9195955 DOI: 10.1128/aem.00543-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Phenazines are an important class of secondary metabolites and are primarily named for their heterocyclic phenazine cores, including phenazine-1-carboxylic acid (PCA) and its derivatives, such as phenazine-1-carboxamide (PCN) and pyocyanin (PYO). Although several genes involved in the degradation of PCA and PYO have been reported so far, the genetic foundations of PCN degradation remain unknown. In this study, a PCN-degrading bacterial strain, Sphingomonas histidinilytica DS-9, was isolated. The gene pcnH, encoding a novel amidase responsible for the initial step of PCN degradation, was cloned by genome comparison and subsequent experimental validation. PcnH catalyzed the hydrolysis of the amide bond of PCN to produce PCA, which shared low identity (only 26 to 33%) with reported amidases. The Km and kcat values of PcnH for PCN were 33.22 ± 5.70 μM and 18.71 ± 0.52 s-1, respectively. PcnH has an Asp-Lys-Cys motif, which is conserved among amidases of the isochorismate hydrolase-like (IHL) superfamily. The replacement of Asp37, Lys128, and Cys163 with alanine in PcnH led to the complete loss of enzymatic activity. Furthermore, the genes pcaA1A2A3A4 and pcnD were found to encode PCA 1,2-dioxygenase and 1,2-dihydroxyphenazine (2OHPC) dioxygenase, which were responsible for the subsequent degradation steps of PCN. The PCN-degradative genes were highly conserved in some bacteria of the genus Sphingomonas, with slight variations in the sequence identities. IMPORTANCE Phenazines have been widely acknowledged as a natural antibiotic for more than 150 years, but their degradation mechanisms are still not completely elucidated. Compared with the studies on the degradation mechanism of PCA and PYO, little is known regarding PCN degradation by far. Previous studies have speculated that its initial degradation step may be catalyzed by an amidase, but no further studies have been conducted. This study identified a novel amidase, PcnH, that catalyzed the hydrolysis of PCN to PCA. In addition, the PCA 1,2-dioxygenase PcaA1A2A3A4 and 2OHPC dioxygenase PcnD were also found to be involved in the subsequent degradation steps of PCN in S. histidinilytica DS-9. And the genes responsible for PCN catabolism are highly conserved in some strains of Sphingomonas. These results deepen our understanding of the PCN degradation mechanism.
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19
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Pati SG, Bopp CE, Kohler HPE, Hofstetter TB. Substrate-Specific Coupling of O 2 Activation to Hydroxylations of Aromatic Compounds by Rieske Non-heme Iron Dioxygenases. ACS Catal 2022; 12:6444-6456. [PMID: 35692249 PMCID: PMC9171724 DOI: 10.1021/acscatal.2c00383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/09/2022] [Indexed: 02/07/2023]
Abstract
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Rieske dioxygenases
catalyze the initial steps in the hydroxylation
of aromatic compounds and are critical for the metabolism of xenobiotic
substances. Because substrates do not bind to the mononuclear non-heme
FeII center, elementary steps leading to O2 activation
and substrate hydroxylation are difficult to delineate, thus making
it challenging to rationalize divergent observations on enzyme mechanisms,
reactivity, and substrate specificity. Here, we show for nitrobenzene
dioxygenase, a Rieske dioxygenase capable of transforming nitroarenes
to nitrite and substituted catechols, that unproductive O2 activation with the release of the unreacted substrate and reactive
oxygen species represents an important path in the catalytic cycle.
Through correlation of O2 uncoupling for a series of substituted
nitroaromatic compounds with 18O and 13C kinetic
isotope effects of dissolved O2 and aromatic substrates,
respectively, we show that O2 uncoupling occurs after the
rate-limiting formation of FeIII-(hydro)peroxo species
from which substrates are hydroxylated. Substituent effects on the
extent of O2 uncoupling suggest that the positioning of
the substrate in the active site rather than the susceptibility of
the substrate for attack by electrophilic oxygen species is responsible
for unproductive O2 uncoupling. The proposed catalytic
cycle provides a mechanistic basis for assessing the very different
efficiencies of substrate hydroxylation vs unproductive O2 activation and generation of reactive oxygen species in reactions
catalyzed by Rieske dioxygenases.
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Affiliation(s)
- Sarah G. Pati
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Charlotte E. Bopp
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
| | - Hans-Peter E. Kohler
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Thomas B. Hofstetter
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zürich, 8092 Zürich, Switzerland
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20
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Cheng M, Chen D, Parales RE, Jiang J. Oxygenases as Powerful Weapons in the Microbial Degradation of Pesticides. Annu Rev Microbiol 2022; 76:325-348. [PMID: 35650666 DOI: 10.1146/annurev-micro-041320-091758] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oxygenases, which catalyze the reductive activation of O2 and incorporation of oxygen atoms into substrates, are widely distributed in aerobes. They function by switching the redox states of essential cofactors that include flavin, heme iron, Rieske non-heme iron, and Fe(II)/α-ketoglutarate. This review summarizes the catalytic features of flavin-dependent monooxygenases, heme iron-dependent cytochrome P450 monooxygenases, Rieske non-heme iron-dependent oxygenases, Fe(II)/α-ketoglutarate-dependent dioxygenases, and ring-cleavage dioxygenases, which are commonly involved in pesticide degradation. Heteroatom release (hydroxylation-coupled hetero group release), aromatic/heterocyclic ring hydroxylation to form ring-cleavage substrates, and ring cleavage are the main chemical fates of pesticides catalyzed by these oxygenases. The diversity of oxygenases, specificities for electron transport components, and potential applications of oxygenases are also discussed. This article summarizes our current understanding of the catalytic mechanisms of oxygenases and a framework for distinguishing the roles of oxygenases in pesticide degradation. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Minggen Cheng
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China;
| | - Dian Chen
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Rebecca E Parales
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, California, USA
| | - Jiandong Jiang
- Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China;
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21
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Liu J, Bao Y, Zhang X, Zhao S, Qiu J, Li N, He J. Anaerobic biodegradation and detoxification of chloroacetamide herbicides by a novel Proteiniclasticum sediminis BAD-10 T. ENVIRONMENTAL RESEARCH 2022; 209:112859. [PMID: 35114144 DOI: 10.1016/j.envres.2022.112859] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Chloroacetamide herbicides (CAAHs) are important herbicides that were widely used to control agricultural weeds. However, their mass applications have seriously contaminated environment, and they are toxic to living beings. CAAHs are easy to enter anoxic environments such as subsoil, wetland sediment, and groundwater, where CAAHs are mainly degraded by anaerobic organisms. To date, there are no research on the anaerobic degradation of CAAHs by pure isolate and toxicity of anaerobic metabolites of CAAHs. In this study, the anaerobic degradation kinetics and metabolites of CAAHs by an anaerobic isolate BAD-10T and the toxicity of anaerobic metabolites were studied. Isolate BAD-10T could degrade alachlor, acetochlor, propisochlor, butachlor, pretilachlor and metolachlor with the degradation kinetics fitting the pseudo-first-order kinetics equation. The degradation rates of CAAHs were significantly affected by the length of N-alkoxyalkyl groups, the shorter the N-alkoxyalkyl groups, the higher the degradation rates. Four metabolites 2-ethyl-6-methyl-N-(ethoxymethyl)-acetanilide (EMEMA), N-(2-methyl-6-ethylphenyl)-acetamide (MEPA), N-2-ethylphenyl acetamide and 2-ethyl-N-carboxyl aniline were identified during acetochlor degradation, and an anaerobic catabolic pathway of acetochlor was proposed. The toxicity of EMEMA and EMPA for zebrafish, Arabidopsis and Chlorella ellipsoidea were obviously lower than that of acetochlor, indicating that the anaerobic degradation of acetochlor by isolate BAD-10T is a detoxification process. The work reveals the anaerobic degradation kinetics and catabolic pathway of CAAHs and highlights a potential application of Proteiniclasticum sediminis BAD-10T for bioremediation of CAAHs residue-contaminated environment.
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Affiliation(s)
- Junwei Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China
| | - Yixuan Bao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China
| | - Xuan Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China
| | - Shiyu Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China
| | - Na Li
- College of Life Science and Agricultural Engineering, Nanyang Normal University, Nanyang, Henan, 473061, PR China.
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China.
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22
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Malla MA, Dubey A, Raj A, Kumar A, Upadhyay N, Yadav S. Emerging frontiers in microbe-mediated pesticide remediation: Unveiling role of omics and In silico approaches in engineered environment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 299:118851. [PMID: 35085655 DOI: 10.1016/j.envpol.2022.118851] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/09/2022] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The overuse of pesticides for augmenting agriculture productivity always comes at the cost of environment, biodiversity, and human health and has put the land, water, and environmental footprints under severe threat throughout the globe. Underpinning and maximizing the microbiome functions in pesticide-contaminated environments has become a prerequisite for a sustainable environment and resilient agriculture. It is imperative to elucidate the metabolic network of the microbial communities and environmental variables at the contaminated site to predict the best strategy for remediation and soil microbe-pesticide interactions. High throughput next-generation sequencing and in silico analysis allow us to identify and discern the members and characteristics of core microbiomes at the contaminated site. Integration of modern high throughput multi-omics investigations and informatics pipelines provide novel approaches and pathways to capitalize on the core microbiomes for enhancing environmental functioning and mitigation. The role of eco-genomics tools in visualising the microbial network, taxonomy, functional potential, and environmental variables in contaminated habitats is discussed in this review. The integrated role of the potential microbe identification as individual or consortia, mechanistic approach for pesticide degradation, identification of responsible enzymes/genes, and in silico approach is emphasized for the prospects of the area.
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Affiliation(s)
- Muneer Ahmad Malla
- Department of Zoology, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India; Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India
| | - Anamika Dubey
- Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India
| | - Aman Raj
- Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India
| | - Ashwani Kumar
- Metagenomics and Secretomics Research Laboratory, Department of Botany, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India.
| | - Niraj Upadhyay
- Department of Chemistry, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India
| | - Shweta Yadav
- Department of Zoology, Dr. Harisingh Gour University (Central University), Sagar, 470003, MP, India
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23
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Parvulescu VI, Epron F, Garcia H, Granger P. Recent Progress and Prospects in Catalytic Water Treatment. Chem Rev 2021; 122:2981-3121. [PMID: 34874709 DOI: 10.1021/acs.chemrev.1c00527] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Presently, conventional technologies in water treatment are not efficient enough to completely mineralize refractory water contaminants. In this context, the implementation of catalytic processes could be an alternative. Despite the advantages provided in terms of kinetics of transformation, selectivity, and energy saving, numerous attempts have not yet led to implementation at an industrial scale. This review examines investigations at different scales for which controversies and limitations must be solved to bridge the gap between fundamentals and practical developments. Particular attention has been paid to the development of solar-driven catalytic technologies and some other emerging processes, such as microwave assisted catalysis, plasma-catalytic processes, or biocatalytic remediation, taking into account their specific advantages and the drawbacks. Challenges for which a better understanding related to the complexity of the systems and the coexistence of various solid-liquid-gas interfaces have been identified.
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Affiliation(s)
- Vasile I Parvulescu
- Department of Organic Chemistry, Biochemistry and Catalysis, University of Bucharest, B-dul Regina Elisabeta 4-12, Bucharest 030016, Romania
| | - Florence Epron
- Université de Poitiers, CNRS UMR 7285, Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), 4 rue Michel Brunet, TSA 51106, 86073 Poitiers Cedex 9, France
| | - Hermenegildo Garcia
- Instituto Universitario de Tecnología Química, Universitat Politecnica de Valencia-Consejo Superior de Investigaciones Científicas, Universitat Politencia de Valencia, Av. de los Naranjos s/n, 46022 Valencia, Spain
| | - Pascal Granger
- CNRS, Centrale Lille, Univ. Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, Univ. Lille, F-59000 Lille, France
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24
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Tyohemba RL, Pillay L, Humphries MS. Bioaccumulation of current-use herbicides in fish from a global biodiversity hotspot: Lake St Lucia, South Africa. CHEMOSPHERE 2021; 284:131407. [PMID: 34323786 DOI: 10.1016/j.chemosphere.2021.131407] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Agricultural pesticides threaten aquatic systems and biodiversity at a global scale, but limited information is available on the accumulation of current-use herbicides in tissues of aquatic organisms. Here, we examine the potential exposure and accumulation of currently used herbicides in two species of fish from Lake St Lucia, a global biodiversity hotspot located in South Africa. Muscle tissue samples were analysed for 11 widely used multi-residue and phenoxy-acid herbicides. Herbicide residues were detected in all samples analysed, with total concentrations ranging from 44.3 to 238 ng g-1 (Clarias gariepinus) and 72.2-291 ng g-1 dw (Oreochromis mossambicus). The most prominent herbicides detected included the two phenoxy-acid herbicides, MCPA (17.6 ± 12 ng g-1) and 2,4-D (28.9 ± 16 ng g-1), along with acetochlor (15.4 ± 5.8 ng g-1), atrazine (12.7 ± 7.1 ng g-1) and terbuthylazine (12.4 ± 12 ng g-1). Results indicate that fish at Lake St Lucia accumulate a complex mixture of herbicides, some previously unreported in tissue, highlighting the potential threat that agricultural runoff may pose to conservation areas. However, assessing the impact of herbicide accumulation on wild fish populations is difficult at present and urgent toxicological data are needed to better understand chronic exposure effects on aquatic organisms. A preliminary human health risk assessment indicated minimal risk associated with the consumption of local fish, but potential additive and synergistic effects of contaminant mixtures remain unknown.
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Affiliation(s)
- Raymond Lubem Tyohemba
- School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa.
| | - Letitia Pillay
- School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa
| | - Marc S Humphries
- School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa.
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25
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Liu J, Bao Y, Zhang X, Zhang K, Chen S, Wu H, He J. Proteiniclasticum sediminis sp. nov., an obligate anaerobic bacterium isolated from anaerobic sludge. Antonie van Leeuwenhoek 2021; 114:1541-1549. [PMID: 34401954 DOI: 10.1007/s10482-021-01620-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/08/2021] [Indexed: 11/26/2022]
Abstract
An obligate anaerobic bacterial BAD-10 T was isolated from anaerobic acetochlor-degrading sludge. The strain was Gram-stain negative, curved rod-shaped, non-motile and non-spore-forming. Growth was observed in PYT medium at pH 6.0-9.0 (optimum, pH 7.5), at 25-47 °C (37 °C) and with 0-1.0% NaCl (w/v, 0%). Strain BAD-10 T could degrade acetochlor. The major fermentation products from peptone-yeast (PY) medium were acetate and butyrate. The predominant cellular fatty acids were iso-C15:0 FAME, anteiso-C15:0 FAME and C16:0 FAME. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain BAD-10 T showed closest affiliation to Proteiniclasticum ruminis D3RC-2 T, with a sequence similarity of 97.6%. Genome sequencing revealed a genome size of 2,983,986 bp, a G + C content of 51.4 mol% and protein-coding genes of 3,102. The average nucleotide identity and in silico DNA-DNA hybridization values between strain BAD-10 T and Proteiniclasticum ruminis D3RC-2 T were 71.0% and 20.4%, respectively, which were below the standard thresholds for species differentiation. On the basis of phenotypic, physiological and phylogenetic evidence, strain BAD-10 T represents a novel species in the genus Proteiniclasticum, for which the name Proteiniclasticum sediminis sp. nov. is proposed. Strain BAD-10 T (= CCTCC AB 2021091 T = KCTC 25288 T) is the type strain of the proposed novel species.
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Affiliation(s)
- Junwei Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Yixuan Bao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Xuan Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Kaiyun Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China
| | - Shuaimin Chen
- Institute of Agricultural Environment and Resources Research, Jilin Academy of Agricultural Sciences, Changchun, Jilin, 130033, People's Republic of China
| | - Haiyan Wu
- Institute of Agricultural Environment and Resources Research, Jilin Academy of Agricultural Sciences, Changchun, Jilin, 130033, People's Republic of China.
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, People's Republic of China.
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26
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Ke Z, Lan M, Yang T, Jia W, Gou Z, Chen K, Jiang J. A two-component monooxygenase for continuous denitration and dechlorination of chlorinated 4-nitrophenol in Ensifer sp. strain 22-1. ENVIRONMENTAL RESEARCH 2021; 198:111216. [PMID: 33971135 DOI: 10.1016/j.envres.2021.111216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
The environmental fates of chlorinated 4-nitrophenols, 2,6-dichloro-4-nitrophenol (2,6-DCNP) and 2-chloro-4-nitrophenol (2C4NP), mediated via microbial catabolism have attracted great attention due to their high toxicity and persistence in the environment. In this study, a strain of Ensifer sp. 22-1 that was capable of degrading both 2,6-DCNP and 2C4NP was isolated from a halogenated aromatic-contaminated soil sample. A gene cluster cnpBADCERM was predicted to be involved in the catabolism of 2,6-DCNP and 2C4NP based on genome sequence analysis. A two-component monooxygenase CnpAB, composed of an oxygenase component (CnpA) and a reductase component (CnpB), was confirmed to catalyze the continuous denitration and dechlorination of 2,6-DCNP and 2C4NP to 6-chlorohydroxyquinol (6-CHQ) and hydroxyquinol (HQ), respectively. Knockout of cnpA resulted in the complete loss of the capacity for strain 22-1 to degrade 2,6-DCNP and 2C4NP. Homologous modeling and docking showed that Val155~Ala159, Phe206~Pro209 and Phe446~Arg461 of CnpA participated in the formation of the FAD-binding pocket, and Arg101, Val155 and Asn447 formed hydrogen bonds with 2,6-DCNP/2C4NP in the substrate-binding pocket. This work characterized a new two-component monooxygenase for 2,6-DCNP and 2C4NP, and enriched our understanding of the degradation mechanism of chlorinated nitrophenols (CNPs) by microorganisms.
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Affiliation(s)
- Zhuang Ke
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Minjian Lan
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Tunan Yang
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Weibin Jia
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Zhenjiu Gou
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Kai Chen
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China.
| | - Jiandong Jiang
- Department of Microbiology, Key Lab of Environmental Microbiology for Agriculture, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China; Jiangsu Key Lab for Solid Organic Waste Utilization, 210095, Nanjing, China.
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27
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Current insights into the microbial degradation for butachlor: strains, metabolic pathways, and molecular mechanisms. Appl Microbiol Biotechnol 2021; 105:4369-4381. [PMID: 34021814 DOI: 10.1007/s00253-021-11346-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 05/04/2021] [Accepted: 05/09/2021] [Indexed: 01/08/2023]
Abstract
The herbicide butachlor has been used in huge quantities worldwide, affecting various environmental systems. Butachlor residues have been detected in soil, water, and organisms, and have been shown to be toxic to these non-target organisms. This paper briefly summarizes the toxic effects of butachlor on aquatic and terrestrial animals, including humans, and proposes the necessity of its removal from the environment. Due to long-term exposure, some animals, plants, and microorganisms have developed resistance toward butachlor, indicating that the toxicity of this herbicide can be reduced. Furthermore, we can consider removing butachlor residues from the environment by using such butachlor-resistant organisms. In particular, microbial degradation methods have attracted much attention, with about 30 kinds of butachlor-degrading microorganisms have been found, such as Fusarium solani, Novosphingobium chloroacetimidivorans, Chaetomium globosum, Pseudomonas putida, Sphingomonas chloroacetimidivorans, and Rhodococcus sp. The metabolites and degradation pathways of butachlor have been investigated. In addition, enzymes associated with butachlor degradation have been identified, including CndC1 (ferredoxin), Red1 (reductase), FdX1 (ferredoxin), FdX2 (ferredoxin), Dbo (debutoxylase), and catechol 1,2 dioxygenase. However, few reviews have focused on the microbial degradation and molecular mechanisms of butachlor. This review explores the biochemical pathways and molecular mechanisms of butachlor biodegradation in depth in order to provide new ideas for repairing butachlor-contaminated environments. KEY POINTS: • Biodegradation is a powerful tool for the removal of butachlor. • Dechlorination plays a key role in the degradation of butachlor. • Possible biochemical pathways of butachlor in the environment are described.
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28
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Zhang M, Ren Y, Du S, Zhou Y, Jiang W, Ke Z, Jiang M, Qiu J, He J, Hong Q. A novel hydrolase PyzH catalyses the cleavage of C=N double bond for pymetrozine degradation in Pseudomonas sp. BYT-1. Environ Microbiol 2021; 23:3265-3273. [PMID: 33939873 DOI: 10.1111/1462-2920.15557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 11/26/2022]
Abstract
Pymetrozine is a synthetic pesticide that can be utilized as the sole carbon source by Pseudomonas sp. strain BYT-1. However, the genes involved in the degradation of pymetrozine remain unknown. We used transposon mutagenesis to create a mutant that unable to hydrolyze pymetrozine. The transposon interrupted the gene pyzH, which was cloned by self-formed adaptor PCR. PyzH hydrolyzed the C=N double bond of pymetrozine to produce 4-amino-6-methyl-4,5-dihydro-2H-[1,2,4]triazin-3-one (AMDT) and nicotinaldehyde; the latter inhibits PyzH activity. PyzH can completely hydrolyze pymetrozine in the presence of dehydrogenase ORF6, which can convert nicotinaldehyde into nicotinic acid and relieve the inhibition. H2 18 O-labeling experiments showed that the oxygen atom of nicotinaldehyde came from water instead of oxygen. PyzH homologous genes were also found in other soil isolates able to degrade pymetrozine.
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Affiliation(s)
- Mingliang Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Yijun Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Shilong Du
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Yidong Zhou
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Wankui Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Zhijian Ke
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Mingli Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
| | - Qing Hong
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, China
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29
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Ganesh Kumar A, Manisha D, Sujitha K, Magesh Peter D, Kirubagaran R, Dharani G. Genome sequence analysis of deep sea Aspergillus sydowii BOBA1 and effect of high pressure on biodegradation of spent engine oil. Sci Rep 2021; 11:9347. [PMID: 33931710 PMCID: PMC8087790 DOI: 10.1038/s41598-021-88525-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/30/2021] [Indexed: 02/02/2023] Open
Abstract
A deep-sea fungus Aspergillus sydowii BOBA1 isolated from marine sediment at a depth of 3000 m was capable of degrading spent engine (SE) oil. The response of immobilized fungi towards degradation at elevated pressure was studied in customized high pressure reactors without any deviation in simulating in situ deep-sea conditions. The growth rate of A. sydowii BOBA1 in 0.1 MPa was significantly different from the growth at 10 MPa pressure. The degradation percentage reached 71.2 and 82.5% at atmospheric and high pressure conditions, respectively, within a retention period of 21 days. The complete genome sequence of BOBA1 consists of 38,795,664 bp in size, comprises 2582 scaffolds with predicted total coding genes of 18,932. A total of 16,247 genes were assigned with known functions and many families found to have a potential role in PAHs and xenobiotic compound metabolism. Functional genes controlling the pathways of hydrocarbon and xenobiotics compound degrading enzymes such as dioxygenase, decarboxylase, hydrolase, reductase and peroxidase were identified. The spectroscopic and genomic analysis revealed the presence of combined catechol, gentisate and phthalic acid degradation pathway. These results of degradation and genomic studies evidenced that this deep-sea fungus could be employed to develop an eco-friendly mycoremediation technology to combat the oil polluted marine environment. This study expands our knowledge on piezophilic fungi and offer insight into possibilities about the fate of SE oil in deep-sea.
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Affiliation(s)
- A. Ganesh Kumar
- grid.454780.a0000 0001 0683 2228Marine Biotechnology Division, National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, 600100 Tamil Nadu India
| | - D. Manisha
- grid.454780.a0000 0001 0683 2228Marine Biotechnology Division, National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, 600100 Tamil Nadu India
| | - K. Sujitha
- grid.454780.a0000 0001 0683 2228Marine Biotechnology Division, National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, 600100 Tamil Nadu India
| | - D. Magesh Peter
- grid.454780.a0000 0001 0683 2228Marine Biotechnology Division, National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, 600100 Tamil Nadu India
| | - R. Kirubagaran
- grid.454780.a0000 0001 0683 2228Marine Biotechnology Division, National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, 600100 Tamil Nadu India
| | - G. Dharani
- grid.454780.a0000 0001 0683 2228Marine Biotechnology Division, National Institute of Ocean Technology, Ministry of Earth Sciences (MoES), Government of India, Chennai, 600100 Tamil Nadu India
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Liu HM, Yuan M, Liu AM, Ren L, Zhu GP, Sun LN. A bifunctional enzyme belonging to cytochrome P450 family involved in the O-dealkylation and N-dealkoxymethylation toward chloroacetanilide herbicides in Rhodococcus sp. B2. Microb Cell Fact 2021; 20:61. [PMID: 33663497 PMCID: PMC7934444 DOI: 10.1186/s12934-021-01544-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/18/2021] [Indexed: 11/22/2022] Open
Abstract
Background The chloroacetamide herbicides pretilachlor is an emerging pollutant. Due to the large amount of use, its presence in the environment threatens human health. However, the molecular mechanism of pretilachlor degradation remains unknown. Results Now, Rhodococcus sp. B2 was isolated from rice field and shown to degrade pretilachlor. The maximum pretilachlor degradation efficiency (86.1%) was observed at a culture time of 5 d, an initial substrate concentration 50 mg/L, pH 6.98, and 30.1 °C. One novel metabolite N-hydroxyethyl-2-chloro-N-(2, 6-diethyl-phenyl)-acetamide was identified by gas chromatography-mass spectrometry (GC–MS). Draft genome comparison demonstrated that a 32,147-bp DNA fragment, harboring gene cluster (EthRABCDB2), was absent from the mutant strain TB2 which could not degrade pretilachlor. The Eth gene cluster, encodes an AraC/XylS family transcriptional regulator (EthRB2), a ferredoxin reductase (EthAB2), a cytochrome P450 monooxygenase (EthBB2), a ferredoxin (EthCB2) and a 10-kDa protein of unknown function (EthDB2). Complementation with EthABCDB2 and EthABDB2, but not EthABCB2 in strain TB2 restored its ability to degrade chloroacetamide herbicides. Subsequently, codon optimization of EthABCDB2 was performed, after which the optimized components were separately expressed in Escherichia coli, and purified using Ni-affinity chromatography. A mixture of EthABCDB2 or EthABDB2 but not EthABCB2 catalyzed the N-dealkoxymethylation of alachlor, acetochlor, butachlor, and propisochlor and O-dealkylation of pretilachlor, revealing that EthDB2 acted as a ferredoxin in strain B2. EthABDB2 displayed maximal activity at 30 °C and pH 7.5. Conclusions This is the first report of a P450 family oxygenase catalyzing the O-dealkylation and N-dealkoxymethylation of pretilachlor and propisochlor, respectively. And the results of the present study provide a microbial resource for the remediation of chloroacetamide herbicides-contaminated sites.![]()
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Affiliation(s)
- Hong-Ming Liu
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China
| | - Meng Yuan
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China
| | - Ai-Min Liu
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China
| | - Lei Ren
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Guo-Ping Zhu
- The Research Center of Life Omics and Health, Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu, 241000, Anhui, People's Republic of China.
| | - Li-Na Sun
- Eco-Environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, People's Republic of China.
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Fagervold SK, Rohée C, Rodrigues AMS, Stien D, Lebaron P. Efficient degradation of the organic UV filter benzophenone-3 by Sphingomonas wittichii strain BP14P isolated from WWTP sludge. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143674. [PMID: 33248773 DOI: 10.1016/j.scitotenv.2020.143674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/03/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Benzophenone-3 (BP3) is a widely used organic UV filter present in many environmental compartments. One way BP3 is released into the environment is through effluents from wastewater treatment plants (WWTPs). These plants are possible sources for degradation activity and WWTP sludge may potentially degrade BP3. Our goal was to identify any BP3 degrading microorganism(s) in WWTP sludge and to investigate whether the degradation was co-metabolic. Initial WWTP sludge microcosms spiked with BP3 showed 100% degradation after 20 days. Multiple transfers of these microcosms, while maintaining a strong selective pressure for BP3 degradation capabilities, resulted in the dominance of one bacterial strain. This strain was identified as Sphingomonas wittichii BP14P and was subsequently isolated. It was shown to degrade BP3 in a growth dependent manner. Strain BP14P utilized BP3 as the sole energy and carbon source and completely degraded BP3 after 7 days in minimal media. We tested the capability of BP14P to degrade nine other UV filters, but the degradation ability seemed to be restricted to BP3. However, whether this specificity is due to the lack of degradation genes, cellular transport or low bioavailability of the other UV filters remained unclear. The efficient degradation of BP3 by a group of bacteria well known for their potential for xenobiotic degradation is an important step forward for a complete risk assessment of the long-term environmental impact of BP3.
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Affiliation(s)
- S K Fagervold
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes, LBBM, F-66650 Banyuls-sur-mer, France.
| | - C Rohée
- Pierre Fabre Dermo-Cosmétique, Centre de Recherche & Développement Pierre Fabre, 31000 Toulouse, France
| | - A M S Rodrigues
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes, LBBM, F-66650 Banyuls-sur-mer, France
| | - D Stien
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes, LBBM, F-66650 Banyuls-sur-mer, France
| | - P Lebaron
- Sorbonne Université, CNRS, Laboratoire de Biodiversité et Biotechnologies Microbiennes, LBBM, F-66650 Banyuls-sur-mer, France
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Jiang W, Liu Y, Ke Z, Zhang L, Zhang M, Zhou Y, Wang H, Wu C, Qiu J, Hong Q. Substrate preference of carbamate hydrolase CehA reveals its environmental behavior. JOURNAL OF HAZARDOUS MATERIALS 2021; 403:123677. [PMID: 32835992 DOI: 10.1016/j.jhazmat.2020.123677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/30/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
The cehA gene is the earliest reported and most widely found carbaryl hydrolase gene. CehA detoxifies carbaryl and other carbamate pesticides via de-esterification. Currently, there is no systematic research available on substrate preference or the mechanism of CehA action in different hosts. In this study, we found that CehA from different hosts is highly conserved, with more than 99% amino acid sequence similarity, and that transposable elements exist in both the upstream and downstream regions of cehA. By introducing point mutations into the cehA gene of Sphingobium sp. CFD-1, we obtained and heterologously expressed all reported CehA(CehAS) encoding genes. Assays to determine enzymatic properties and substrate profiles of CehAS showed that each CehA has a significant substrate preference for different carbamate insecticides. Specifically, CehA152Phe/Leu determines the catalytic preference for bicyclic carbamate substrates (carbofuran, carbaryl), while CehA494Thr/Ala and 570Thr/Ile determine the preference for monocyclic carbamate substrates (isoprocarb, propoxur) and linear carbamate substrates (oxamyl, aldicarb), respectively. Considering the existence of transposable elements in the flanking regions of cehA, we speculate that the cehA hosts may have acquired the hydrolysis ability, as well as substrate preference for carbamate pesticides, through horizontal gene transfer and genetic copying errors.
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Affiliation(s)
- Wankui Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Yali Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Zhijian Ke
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Lu Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Mingliang Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Yidong Zhou
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Hui Wang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Chenglong Wu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China
| | - Qing Hong
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
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Liu J, Zhang X, Xu J, Qiu J, Zhu J, Cao H, He J. Anaerobic biodegradation of acetochlor by acclimated sludge and its anaerobic catabolic pathway. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:141122. [PMID: 32810802 DOI: 10.1016/j.scitotenv.2020.141122] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 07/10/2020] [Accepted: 07/18/2020] [Indexed: 06/11/2023]
Abstract
Acetochlor is a chloroacetamide herbicide that has been widely used for weed control in recent decades. The contamination from its residue in the environment has raised major serious concerns. The aerobic degradation of acetochlor has been well studied; however, little is known regarding its anaerobic degradation. In the study, anaerobic sludge with high acetochlor degradation efficiency was obtained by pressure acclimation in a continuous flow anaerobic reactor. The acetochlor degradation dynamics followed a first-order kinetic reaction equation. The acclimated sludge could degrade six chloroacetamide herbicides with the degradation efficiencies observed as alachlor > acetochlor > propisochlor > butachlor > pretilachlor > metolachlor, and the N-alkoxyalkyl structure of these herbicides significantly affected their biodegradability. Five metabolites, 2-ethyl-6-methyl-N-(ethoxymethyl)-acetanilide, N-(2-methyl-6-ethylphenyl) acetamide, N-2-ethylphenyl acetamide, N-2-ethylphenyl formamide and 2-ethyl-N-carboxyl aniline were identified, and a putative anaerobic acetochlor degradation pathway, initiated by dechlorination, was subsequently proposed. During acclimation, the community diversity of both eubacteria and archaea in the anaerobic sludge decreased, while the abundance of microbes belonging to genera Sporomusa, Sporobacterium, Dechloromonas, Azotobacter and Methanobacterium were significantly increased and dominated the acclimated sludge, and showing a positive correlation with the acetochlor degradation capacity. These findings should be valuable to elucidate the mechanisms associated with the anaerobic catabolism of acetochlor and facilitate the engineering application of anaerobic treatment for removing acetochlor from wastewater.
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Affiliation(s)
- Junwei Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
| | - Xuan Zhang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
| | - Jianyi Xu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
| | - Jianchun Zhu
- Laboratory Centre of Life Science, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
| | - Hui Cao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China.
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Li N, Peng Q, Yao L, He Q, Qiu J, Cao H, He J, Niu Q, Lu Y, Hui F. Roles of the Gentisate 1,2-Dioxygenases DsmD and GtdA in the Catabolism of the Herbicide Dicamba in Rhizorhabdus dicambivorans Ndbn-20. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9287-9298. [PMID: 32786824 DOI: 10.1021/acs.jafc.0c01523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
3-Chlorogentisate is a key intermediate in the catabolism of the herbicide dicamba in R. dicambivorans Ndbn-20. In this study, we identified two gentisate 1,2-dioxygenases (GDOs), DsmD and GtdA, from Ndbn-20. The amino acid sequence similarity between DsmD and GtdA is 51%. Both of them are dimers and showed activities to gentisate and 3-chlorogentisate but not 3,6-dichlorogentisate (3,6-DCGA) or 6-chlorogentisate in vitro. The kcat/Km of DsmD for 3-chlorogentisate was 28.7 times higher than that of GtdA, whereas the kcat/Km of DsmD for gentisate was only one-fourth of that of GtdA. Transcription of dsmD was dramatically induced by 3-chlorogentisate but not gentisate, whereas gtdA was not induced. Disruption of dsmD resulted in a significant decline in the degradation rates of 3-chlorogentisate and dicamba but had no effect on the degradation of gentisate, whereas the result of disruption of gtdA was converse; the disruption of both dsmD and gtdA led to the inability to degrade 3-chlorogentisate and gentisate. This study revealed that 3-chlorogentisate but not gentisate or 3,6-DCGA is the ring-cleavage substrate in the dicamba degradation pathway in R. dicambivorans Ndbn-20; DsmD is specifically responsible for cleavage of 3-chlorogentisate, whereas GtdA is a general GDO involved in the catabolism of various natural aromatic compounds.
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Affiliation(s)
- Na Li
- School of Life Science and Technology, Nanyang Normal University, Nanyang, Henan 473061, China
| | - Qian Peng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Li Yao
- School of Marine and Biological Engineering, Yancheng Teachers University, Yancheng, Jiangsu 224002, China
| | - Qin He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Hui Cao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Qiuhong Niu
- School of Life Science and Technology, Nanyang Normal University, Nanyang, Henan 473061, China
| | - Yunfeng Lu
- School of Life Science and Technology, Nanyang Normal University, Nanyang, Henan 473061, China
- State Key Laboratory of Motor Vehicle Biofuel Technology, Nanyang, Henan 473000, China
| | - Fengli Hui
- School of Life Science and Technology, Nanyang Normal University, Nanyang, Henan 473061, China
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Chu C, Liu B, Liu J, He J, Lv L, Wang H, Xie X, Tao Q, Chen Q. Phytoremediation of acetochlor residue by transgenic Arabidopsis expressing the acetochlor N-dealkylase from Sphingomonas wittichii DC-6. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 728:138687. [PMID: 32361114 DOI: 10.1016/j.scitotenv.2020.138687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/07/2020] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
Transgenic engineering is an effective way for plants to obtain strong degradation or detoxification abilities to target pollutants. Acetochlor is an important and widely used herbicide, however, its residue is persistent in soil and is toxic to humans and rotation crops. In this study, the degradation ability and tolerance to acetochlor of transgenic Arabidopsis thaliana synthesizing the oxygenase component, CndA, of the bacterial acetochlor N-dealkylase system, CndABC, were investigated. Two transgenic plants, including a cytoplasm transformant, in which the CndA was located in the cytoplasm, and a chloroplast transformant, in which the CndA was located in the chloroplast, were constructed. The cytoplasm transformant acquired only weak acetochlor degradation activity and displayed little acetochlor tolerance. In contrast, the chloroplast transformant exhibited high degradation efficiency and strong tolerance to acetochlor; it could transform 94.3% of 20 μM acetochlor in water within 48 h and eliminate 80.2% of 5 mg/kg acetochlor in soil within 30 d. The metabolite of acetochlor N-dealkylation catalyzed by CndA, 2-chloro-N-(2-methyl-6-ethylphenyl)acetamide (CMEPA), could be released outside the cells by chloroplast transformant and further degraded by indigenous microorganisms in the soil. This study provides an effective strategy for the phytoremediation of acetochlor residue in water and soil.
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Affiliation(s)
- Cuiwei Chu
- College of Life Sciences and Agronomy, Zhoukou Normal University, Zhoukou, Henan 466000, China
| | - Bin Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Junwei Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jian He
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Lijie Lv
- College of Life Sciences, Zaozhuang University, Zaozhuang 277100, China
| | - Hongmei Wang
- College of Life Sciences, Zaozhuang University, Zaozhuang 277100, China
| | - Xiangting Xie
- DBN Biotech Center, Beijing Dabeinong Technology Group Co., Ltd., 100193, PO Box 5109, Beijing, China
| | - Qing Tao
- DBN Biotech Center, Beijing Dabeinong Technology Group Co., Ltd., 100193, PO Box 5109, Beijing, China
| | - Qing Chen
- College of Life Sciences, Zaozhuang University, Zaozhuang 277100, China.
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Ma X, Liang B, Qi M, Yun H, Shi K, Li Z, Guo Y, Yan P, Liu SJ, Wang A. Novel Pathway for Chloramphenicol Catabolism in the Activated Sludge Bacterial Isolate Sphingobium sp. CAP-1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7591-7600. [PMID: 32412239 DOI: 10.1021/acs.est.9b07324] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The chlorinated nitroaromatic antibiotic chloramphenicol (CAP) is a refractory contaminant that is widely present in various environments. However, few CAP-mineralizing bacteria have been documented, and a complete CAP catabolism pathway has yet to be identified. In this study, the bacterial strain Sphingobium sp. CAP-1 was isolated from an activated sludge sample and was shown to be capable of aerobically subsisting on CAP as the sole carbon, nitrogen, and energy source while simultaneously and efficiently degrading CAP. p-Nitrobenzoic acid (PNBA), p-nitrobenzaldehyde (PNBD), protocatechuate (PCA), and the novel side chain C3-hydroxy-oxygenated product of CAP (O-CAP) were identified during CAP degradation. Strain CAP-1 was able to convert O-CAP to intermediate product PNBA. The putative functional genes associated with PNBA catabolism into the tricarboxylic acid cycle via PCA and floc formation were also identified by genome sequencing and comparative proteome analysis. A complete pathway for CAP catabolism was proposed. The discovery of a novel CAP oxidation/detoxification process and a complete pathway for CAP catabolism enriches the fundamental understanding of the bacterial catabolism of antibiotics, providing new insights into the microbial-mediated fate, transformation, and resistance risk of CAP in the environment. The molecular basis of CAP catabolism and floc formation in strain CAP-1 also offers theoretical guidance for the enhanced bioremediation of CAP-containing environments.
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Affiliation(s)
- Xiaodan Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Bin Liang
- School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Mengyuan Qi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Hui Yun
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou 730000, China
| | - Ke Shi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhiling Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yuanqiang Guo
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin 300350, China
| | - Peisheng Yan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Aijie Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
- School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Rogers MS, Lipscomb JD. Salicylate 5-Hydroxylase: Intermediates in Aromatic Hydroxylation by a Rieske Monooxygenase. Biochemistry 2019; 58:5305-5319. [PMID: 31066545 PMCID: PMC6856394 DOI: 10.1021/acs.biochem.9b00292] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rieske oxygenases (ROs) catalyze a large range of oxidative chemistry. We have shown that cis-dihydrodiol-forming Rieske dioxygenases first react with their aromatic substrates via an active site nonheme Fe(III)-superoxide; electron transfer from the Rieske cluster then completes the product-forming reaction. Alternatively, two-electron-reduced Fe(III)-peroxo or hydroxo-Fe(V)-oxo activated oxygen intermediates are possible and may be utilized by other ROs to expand the catalytic range. Here, the reaction of a Rieske monooxygenase, salicylate 5-hydroxylase, that does not form a cis-dihydrodiol is examined. Single-turnover kinetic studies show fast binding of salicylate and O2. Transfer of the Rieske electron required to form the gentisate product occurs through bonds over ∼12 Å and must also be very fast. However, the observed rate constant for this reaction is much slower than expected and sensitive to substrate type. This suggests that initial reaction with salicylate occurs using the same Fe(III)-superoxo-level intermediate as Rieske dioxygenases and that this reaction limits the observed rate of electron transfer. A transient intermediate (λmax = 700 nm) with an electron paramagnetic resonance (EPR) at g = 4.3 is observed after the product is formed in the active site. The use of 17O2 (I = 5/2) results in hyperfine broadening of the g = 4.3 signal, showing that gentisate binds to the mononuclear iron via its C5-OH in the intermediate. The chromophore and EPR signal allow study of product release in the catalytic cycle. Comparison of the kinetics of single- and multiple-turnover reactions shows that re-reduction of the metal centers accelerates product release ∼300-fold, providing insight into the regulatory mechanism of ROs.
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Affiliation(s)
- Melanie S. Rogers
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - John D. Lipscomb
- Department of Biochemistry, Molecular Biology, and Biophysics and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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The Properties of 5-Methyltetrahydrofolate Dehydrogenase (MetF1) and Its Role in the Tetrahydrofolate-Dependent Dicamba Demethylation System in Rhizorhabdus dicambivorans Ndbn-20. J Bacteriol 2019; 201:JB.00096-19. [PMID: 31209079 DOI: 10.1128/jb.00096-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/13/2019] [Indexed: 11/20/2022] Open
Abstract
The herbicide dicamba is initially degraded via the tetrahydrofolate (THF)-dependent demethylation system in Rhizorhabdus dicambivorans Ndbn-20. Two THF-dependent dicamba methyltransferase gene clusters, scaffold 50 and scaffold 66, were found in the genome of strain Ndbn-20. Each cluster contains a dicamba methyltransferase gene and three THF metabolism-related genes, namely, metF (coding for 5,10-CH2-THF reductase), folD (coding for 5,10-CH2-THF dehydrogenase-5,10-methenyl-THF cyclohydrolase), and purU (coding for 10-formyl-THF deformylase). In this study, reverse transcription-PCR (RT-PCR) results showed that only genes in scaffold 66, not those in scaffold 50, were transcribed in dicamba-cultured cells. The metF gene of scaffold 66 (metF1) was expressed in Escherichia coli BL21(DE3), and the product was purified as a His6-tagged protein. Purified MetF1 was found to be a monomer and exhibited 5-CH3-THF dehydrogenase activity in vitro The k cat and Km for 5-CH3-THF were 0.23 s-1 and 16.48 μM, respectively. However, 5,10-CH2-THF reductase activity was not detected for MetF1 under the conditions tested. Gene disruption results showed that metF1 is essential for dicamba degradation, whereas folD1 is dispensable.IMPORTANCE There are several THF-dependent methyltransferase genes and THF-metabolic genes in the genome of R. dicambivorans Ndbn-20; however, which genes are involved in dicamba demethylation and the mechanism underlying THF regeneration remain unknown. This study revealed that scaffold 66 is responsible for dicamba demethylation and that MetF1 physiologically catalyzes the dehydrogenation of 5-CH3-THF to 5,10-CH2-THF in the THF-dependent dicamba demethylation system in R. dicambivorans Ndbn-20. Furthermore, the results showed that MetF1 differs from previously characterized MetF in phylogenesis, biochemical properties, and catalytic activity; e.g., MetF1 in vitro did not show 5,10-CH2-THF reductase activity, which is the physiological function of Escherichia coli MetF. This study provides new insights into the mechanism of the THF-dependent methyltransferase system.
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Kim JH, Kim BH, Brooks S, Kang SY, Summers RM, Song HK. Structural and Mechanistic Insights into Caffeine Degradation by the Bacterial N-Demethylase Complex. J Mol Biol 2019; 431:3647-3661. [PMID: 31412262 DOI: 10.1016/j.jmb.2019.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 01/06/2023]
Abstract
Caffeine, found in many foods, beverages, and pharmaceuticals, is the most used chemical compound for mental alertness. It is originally a natural product of plants and exists widely in environmental soil. Some bacteria, such as Pseudomonas putida CBB5, utilize caffeine as a sole carbon and nitrogen source by degrading it through sequential N-demethylation catalyzed by five enzymes (NdmA, NdmB, NdmC, NdmD, and NdmE). The environmentally friendly enzymatic reaction products, methylxanthines, are high-value biochemicals that are used in the pharmaceutical and cosmetic industries. However, the structures and biochemical properties of bacterial N-demethylases remain largely unknown. Here, we report the structures of NdmA and NdmB, the initial N1- and N3-specific demethylases, respectively. Reverse-oriented substrate bindings were observed in the substrate-complexed structures, offering methyl position specificity for proper N-demethylation. For efficient sequential degradation of caffeine, these enzymes form a unique heterocomplex with 3:3 stoichiometry, which was confirmed by enzymatic assays, fluorescent labeling, and small-angle x-ray scattering. The binary structure of NdmA with the ferredoxin domain of NdmD, which is the first structural information for the plant-type ferredoxin domain in a complex state, was also determined to better understand electron transport during N-demethylation. These findings broaden our understanding of the caffeine degradation mechanism by bacterial enzymes and will enable their use for industrial applications.
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Affiliation(s)
- Jun Hoe Kim
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Bong Heon Kim
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Shelby Brooks
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Seung Yeon Kang
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Ryan M Summers
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
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Identification and Characterization of a Novel pic Gene Cluster Responsible for Picolinic Acid Degradation in Alcaligenes faecalis JQ135. J Bacteriol 2019; 201:JB.00077-19. [PMID: 31160400 DOI: 10.1128/jb.00077-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/30/2019] [Indexed: 11/20/2022] Open
Abstract
Picolinic acid (PA) is a natural toxic pyridine derivative. Microorganisms can degrade and utilize PA for growth. However, the full catabolic pathway of PA and its physiological and genetic foundation remain unknown. In this study, we identified a gene cluster, designated picRCEDFB4B3B2B1A1A2A3, responsible for the degradation of PA from Alcaligenes faecalis JQ135. Our results suggest that PA degradation pathway occurs as follows: PA was initially 6-hydroxylated to 6-hydroxypicolinic acid (6HPA) by PicA (a PA dehydrogenase). 6HPA was then 3-hydroxylated by PicB, a four-component 6HPA monooxygenase, to form 3,6-dihydroxypicolinic acid (3,6DHPA), which was then converted into 2,5-dihydroxypyridine (2,5DHP) by the decarboxylase PicC. 2,5DHP was further degraded to fumaric acid through PicD (2,5DHP 5,6-dioxygenase), PicE (N-formylmaleamic acid deformylase), PicF (maleamic acid amidohydrolase), and PicG (maleic acid isomerase). Homologous pic gene clusters with diverse organizations were found to be widely distributed in Alpha-, Beta-, and Gammaproteobacteria Our findings provide new insights into the microbial catabolism of environmental toxic pyridine derivatives.IMPORTANCE Picolinic acid is a common metabolite of l-tryptophan and some aromatic compounds and is an important intermediate in organic chemical synthesis. Although the microbial degradation/detoxification of picolinic acid has been studied for over 50 years, the underlying molecular mechanisms are still unknown. Here, we show that the pic gene cluster is responsible for the complete degradation of picolinic acid. The pic gene cluster was found to be widespread in other Alpha-, Beta-, and Gammaproteobacteria These findings provide a new perspective for understanding the catabolic mechanisms of picolinic acid in bacteria.
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Ma X, Qi M, Li Z, Zhao Y, Yan P, Liang B, Wang A. Characterization of an efficient chloramphenicol-mineralizing bacterial consortium. CHEMOSPHERE 2019; 222:149-155. [PMID: 30703654 DOI: 10.1016/j.chemosphere.2019.01.131] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 12/25/2018] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
Obtaining efficient antibiotic-mineralizing consortium or pure cultures is a central issue for the deep elimination of antibiotic-contaminated environments. However, the antibiotic chloramphenicol (CAP) mineralizing consortium has not yet been reported. In this study, an efficient CAP-mineralizing consortium was successfully obtained with municipal activated sludge as the initial inoculum. This consortium is capable of aerobically subsisting on CAP as the sole carbon, nitrogen and energy sources and completely degrading 50 mg L-1 CAP within 24 h. After 5 d, 71.50 ± 2.63% of CAP was mineralized and Cl- recovery efficiency was 90.80 ± 7.34%. Interestingly, the CAP degradation efficiency obviously decreased to 18.22 ± 3.52% within 12 h with co-metabolic carbon source glucose. p-nitrobenzoic acid (p-NBA) was identified as an intermediate product during CAP biodegradation. The consortium is also able to utilize p-NBA as the sole carbon and nitrogen sources and almost completely degrade 25 mg L-1p-NBA within 24 h. Microbial community analysis indicated that the dominant genera in the CAP-mineralizing consortium all belong to Proteobacteria (especially Sphingobium with the relative abundance over 63%), and most bacteria could degrade aromatics including p-NBA, suggesting these genera involved in the upstream and downstream pathway of CAP degradation. Although the acclimated consortium has been successively passaged 152 times, the microbial community structure and core genera were not obviously changed, which was consistent with the stable CAP degradation efficiency observed under different generations. This is the first report that the acclimated consortium is able to mineralize CAP through an oxidative pathway with p-NBA as an intermediate product.
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Affiliation(s)
- Xiaodan Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Mengyuan Qi
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhiling Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Youkang Zhao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Peisheng Yan
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Bin Liang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Aijie Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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Cheng M, Yan X, He J, Qiu J, Chen Q. Comparative genome analysis reveals the evolution of chloroacetanilide herbicide mineralization in Sphingomonas wittichii DC-6. Arch Microbiol 2019; 201:907-918. [PMID: 30997539 DOI: 10.1007/s00203-019-01660-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 12/13/2022]
Abstract
The environmental fate of the extensively used chloroacetanilide herbicides (CH) has been a cause of increasing concern in the past decade because of their carcinogenic properties. Although microbes play important roles in CH degradation, Sphingomonas wittichii DC-6 was the first reported CH-mineralizing bacterium. In this study, the complete genome of strain DC-6 was sequenced and comparative genomic analysis was performed using strain DC-6 and other three partial CH-degrading bacteria, Sphingobium quisquiliarum DC-2, Sphingobium baderi DE-13, and Sphingobium sp. MEA3-1. 16S rDNA phylogenetic analysis indicated that strain DC-2, MEA3-1, and DE-13 are closely related and DC-6 has relatively distant genetic relationship with the other three strains. The identified CH degradation genes responsible for the upstream and downstream pathway, including cndA, cmeH, meaXY, and meaAB, were all located in conserved DNA fragments (or genetic islands) in the vicinity of mobile element proteins. Protein BLAST in the NCBI database showed that cndA and cmeH were present in the genomes of other sequenced strains isolated from various habitats; however, the gene compositions in these host strains were completely different from those of other sphingomonads, and codon usage of genes for upstream pathway were also different from that of downstream pathway. These results showed that the upstream and downstream pathways of CH degradation in strain DC-6 have evolved by horizontal gene transfer and gene combination. In addition, the genes of the ring-cleavage pathway were not conserved and may have evolved directly from bacterial degradation of hydroxyquinol. The present study provides insights into the evolutionary strategy and microbial catabolic pathway of CH mineralization.
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Affiliation(s)
- Minggen Cheng
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Xin Yan
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Jian He
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Jiguo Qiu
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
| | - Qing Chen
- Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China. .,College of Life Sciences, Zaozhuang University, Zaozhuang, 277160, Shandong, China.
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Sun G, Zhang M, Liu X, Gao Q, Jiang W, Zhou Y, Wang H, Cui M, Qiu J, Xu J, Hong Q. Isolation and Characterization of the Pymetrozine-Degrading Strain Pseudomonas sp. BYT-1. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:4170-4176. [PMID: 30912660 DOI: 10.1021/acs.jafc.8b06155] [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] [Indexed: 06/09/2023]
Abstract
In this study, we isolated and characterized the bacterial strain Pseudomonas sp. BYT-1, which is capable of degrading pymetrozine and using it as the sole carbon source for growth. Strain BYT-1 could degrade 2.30 mM pymetrozine within 20 h under the optimal conditions of 30 °C and pH 7.0. Investigation of the degradation pathway showed that pymetrozine was oxidatively hydrolyzed to 4-amino-6-methyl-4,5-dihydro-2 H-[1,2,4]triazin-3-one (AMDT) and nicotinic acid (NA). The former accumulates as the end product in the culture, whereas the latter was hydroxylated to 6-hydroxynicotinic acid (6HNA) and subjected to further degradation. The transformation of pymetrozine to AMDT and NA by the cell-free extracts of strain BYT-1 also supported that the oxidative hydrolysis of the C═N double bond in pymetrozine was the initial degradation step. This is the first report on a pure bacterial culture with the ability to degrade pymetrozine. These findings enhance our understanding of the microbial degradation mechanism of pymetrozine.
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Affiliation(s)
- Gaojie Sun
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Mingliang Zhang
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Xiaoan Liu
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Qinqin Gao
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Wankui Jiang
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Yidong Zhou
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Hui Wang
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Mengdi Cui
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Jiguo Qiu
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
| | - Jianhong Xu
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base, Ministry of Science and Technology, Institute of Food Safety and Nutrition , Jiangsu Academy of Agricultural Sciences , Nanjing 210014 , People's Republic of China
| | - Qing Hong
- Key Lab of Microbiological Agricultural Environment, Ministry of Agriculture, College of Life Science , Nanjing Agriculture University , Nanjing 210095 , People's Republic of China
- Jiangsu Key Laboratory for Food Quality and Safety, State Key Laboratory Cultivation Base, Ministry of Science and Technology, Institute of Food Safety and Nutrition , Jiangsu Academy of Agricultural Sciences , Nanjing 210014 , People's Republic of China
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Liu B, Peng Q, Sheng M, Hu S, Qian M, Fan B, He J. Directed Evolution of Sulfonylurea Esterase and Characterization of a Variant with Improved Activity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:836-843. [PMID: 30585487 DOI: 10.1021/acs.jafc.8b06198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Esterase SulE detoxicates a variety of sulfonylurea herbicides through de-esterification. SulE exhibits high activity against thifensulfuron-methyl but low activity against other sulfonylureas. In this study, two variants, m2311 (P80R) and m0569 (P80R and G176A), with improved activity were screened from a mutation library constructed by error-prone PCR. Variant m2311 showed a higher activity against sulfonylureas in comparison variant m0569 and was further investigated. The kcat/ Km value of variant m2311 for metsulfuron-methyl, sulfometuron-methyl, chlorimuron-ethyl, tribenuron-methyl, and ethametsulfuron-methyl increased by 3.20-, 1.72-, 2.94-, 2.26- and 2.96-fold, respectively, in comparison with the wild type. Molecular modeling suggested that the activity improvement of variant m2311 is due to the substitution of Pro80 by arginine, leading to the formation of new hydrogen bonds between the enzyme and substrate. This study facilitates further elucidation of the structure and function of SulE and provides an improved gene resource for the detoxification of sulfonylurea residues and the genetic engineering of sulfonylurea-resistant crops.
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Affiliation(s)
- Bin Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Qian Peng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Mengyao Sheng
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Shishan Hu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Meng Qian
- Laboratory Centre of Life Science, College of Life Sciences , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
| | - Ben Fan
- College of Forest Resources and Environment , Nanjing Forestry University , Nanjing , Jiangsu , People's Republic of China
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences , Nanjing Agricultural University , Nanjing 210095 , Jiangsu , People's Republic of China
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Ren L, Jia Y, Zhang R, Lin Z, Zhen Z, Hu H, Yan Y. Insight Into Metabolic Versatility of an Aromatic Compounds-Degrading Arthrobacter sp. YC-RL1. Front Microbiol 2018; 9:2438. [PMID: 30364317 PMCID: PMC6193132 DOI: 10.3389/fmicb.2018.02438] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/24/2018] [Indexed: 01/11/2023] Open
Abstract
The genus Arthrobacter is ubiquitously distributed in different natural environments. Many xenobiotic-degrading Arthrobacter strains have been isolated and described; however, few have been systematically characterized with regard to multiple interrelated metabolic pathways and the genes that encode them. In this study, the biodegradability of seven aromatic compounds by Arthrobacter sp. YC-RL1 was investigated. Strain YC-RL1 could efficiently degrade p-xylene (PX), naphthalene, phenanthrene, biphenyl, p-nitrophenol (PNP), and bisphenol A (BPA) under both separated and mixed conditions. Based on the detected metabolic intermediates, metabolic pathways of naphthalene, biphenyl, PNP, and BPA were proposed, which indicated that strain YC-RL1 harbors systematic metabolic pathways toward aromatic compounds. Further, genomic analysis uncovered part of genes involved in the proposed pathways. Both intradiol and extradiol ring-cleavage dioxygenase genes were identified in the genome of strain YC-RL1. Meanwhile, gene clusters predicted to encode the degradation of biphenyl (bph), para-substituted phenols (npd) and protocatechuate (pca) were identified, and bphA1A2BCD was proposed to be a novel biphenyl-degrading gene cluster. The complete metabolic pathway of biphenyl was deduced via intermediates and functional gene analysis (bph and pca gene clusters). One of the these genes encoding ring-cleavage dioxygenase in bph gene cluster, a predicted 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC) gene, was cloned and its activity was confirmed by heterologous expression. This work systematically illuminated the metabolic versatility of aromatic compounds in strain YC-RL1 via the combination of metabolites identification, genomics analysis and laboratory experiments. These results suggested that strain YC-RL1 might be a promising candidate for the bioremediation of aromatic compounds pollution sites.
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Affiliation(s)
- Lei Ren
- Agricultural College, Guangdong Ocean University, Zhanjiang, China.,Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yang Jia
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rui Zhang
- Agricultural College, Guangdong Ocean University, Zhanjiang, China.,Shenzhen Research Institute of Guangdong Ocean University, Shenzhen, China
| | - Zhong Lin
- Agricultural College, Guangdong Ocean University, Zhanjiang, China.,Faculty of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang, China
| | - Zhen Zhen
- Agricultural College, Guangdong Ocean University, Zhanjiang, China
| | - Hanqiao Hu
- Agricultural College, Guangdong Ocean University, Zhanjiang, China
| | - Yanchun Yan
- Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China
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Hydrolase CehA and Monooxygenase CfdC Are Responsible for Carbofuran Degradation in Sphingomonas sp. Strain CDS-1. Appl Environ Microbiol 2018; 84:AEM.00805-18. [PMID: 29884759 DOI: 10.1128/aem.00805-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/31/2018] [Indexed: 01/29/2023] Open
Abstract
Carbofuran, a broad-spectrum systemic insecticide, has been extensively used for approximately 50 years. Diverse carbofuran-degrading bacteria have been described, among which sphingomonads have exhibited an extraordinary ability to catabolize carbofuran; other bacteria can only convert carbofuran to carbofuran phenol, while all carbofuran-degrading sphingomonads can degrade both carbofuran and carbofuran phenol. However, the genetic basis of carbofuran catabolism in sphingomonads has not been well elucidated. In this work, we sequenced the draft genome of Sphingomonas sp. strain CDS-1 that can transform both carbofuran and carbofuran phenol but fails to grow on them. On the basis of the hypothesis that the genes involved in carbofuran catabolism are highly conserved among carbofuran-degrading sphingomonads, two such genes, cehACDS-1 and cfdCCDS-1, were predicted from the 84 open reading frames (ORFs) that share ≥95% nucleic acid similarities between strain CDS-1 and another sphingomonad Novosphingobium sp. strain KN65.2 that is able to mineralize the benzene ring of carbofuran. The results of the gene knockout, genetic complementation, heterologous expression, and enzymatic experiments reveal that cehACDS-1 and cfdCCDS-1 are responsible for the conversion of carbofuran and carbofuran phenol, respectively, in strain CDS-1. CehACDS-1 hydrolyzes carbofuran to carbofuran phenol. CfdCCDS-1, a reduced flavin mononucleotide (FMNH2)- or reduced flavin adenine dinucleotide (FADH2)-dependent monooxygenase, hydroxylates carbofuran phenol at the benzene ring in the presence of NADH, FMN/FAD, and the reductase CfdX. It is worth noting that we found that carbaryl hydrolase CehAAC100, which was previously demonstrated to have no activity toward carbofuran, can actually convert carbofuran to carbofuran phenol, albeit with very low activity.IMPORTANCE Due to the extensive use of carbofuran over the past 50 years, bacteria have evolved catabolic pathways to mineralize this insecticide, which plays an important role in eliminating carbofuran residue in the environment. This study revealed the genetic determinants of carbofuran degradation in Sphingomonas sp. strain CDS-1. We speculate that the close homologues cehA and cfdC are highly conserved among other carbofuran-degrading sphingomonads and play the same roles as those described here. These findings deepen our understanding of the microbial degradation mechanism of carbofuran and lay a foundation for the better use of microbes to remediate carbofuran contamination.
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A Novel Degradation Mechanism for Pyridine Derivatives in Alcaligenes faecalis JQ135. Appl Environ Microbiol 2018; 84:AEM.00910-18. [PMID: 29802182 DOI: 10.1128/aem.00910-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 05/16/2018] [Indexed: 11/20/2022] Open
Abstract
5-Hydroxypicolinic acid (5HPA), a natural pyridine derivative, is microbially degraded in the environment. However, the physiological, biochemical, and genetic foundations of 5HPA metabolism remain unknown. In this study, an operon (hpa), responsible for 5HPA degradation, was cloned from Alcaligenes faecalis JQ135. HpaM was a monocomponent flavin adenine dinucleotide (FAD)-dependent monooxygenase and shared low identity (only 28 to 31%) with reported monooxygenases. HpaM catalyzed the ortho decarboxylative hydroxylation of 5HPA, generating 2,5-dihydroxypyridine (2,5DHP). The monooxygenase activity of HpaM was FAD and NADH dependent. The apparent Km values of HpaM for 5HPA and NADH were 45.4 μM and 37.8 μM, respectively. The genes hpaX, hpaD, and hpaF were found to encode 2,5DHP dioxygenase, N-formylmaleamic acid deformylase, and maleamate amidohydrolase, respectively; however, the three genes were not essential for 5HPA degradation in A. faecalis JQ135. Furthermore, the gene maiA, which encodes a maleic acid cis-trans isomerase, was essential for the metabolism of 5HPA, nicotinic acid, and picolinic acid in A. faecalis JQ135, indicating that it might be a key gene in the metabolism of pyridine derivatives. The genes and proteins identified in this study showed a novel degradation mechanism of pyridine derivatives.IMPORTANCE Unlike the benzene ring, the uneven distribution of the electron density of the pyridine ring influences the positional reactivity and interaction with enzymes; e.g., the ortho and para oxidations are more difficult than the meta oxidations. Hydroxylation is an important oxidation process for the pyridine derivative metabolism. In previous reports, the ortho hydroxylations of pyridine derivatives were catalyzed by multicomponent molybdenum-containing monooxygenases, while the meta hydroxylations were catalyzed by monocomponent FAD-dependent monooxygenases. This study identified the new monocomponent FAD-dependent monooxygenase HpaM that catalyzed the ortho decarboxylative hydroxylation of 5HPA. In addition, we found that the maiA gene coding for maleic acid cis-trans isomerase was pivotal for the metabolism of 5HPA, nicotinic acid, and picolinic acid in A. faecalis JQ135. This study provides novel insights into the microbial metabolism of pyridine derivatives.
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Wang H, Jiang K, Zhu Z, Jiang W, Yang Z, Zhu S, Qiu J, Yan X, He J, He Q, Hong Q. Optimization of fed-batch fermentation and direct spray drying in the preparation of microbial inoculant of acetochlor-degrading strain Sphingomonas sp. DC-6. 3 Biotech 2018; 8:294. [PMID: 29963354 DOI: 10.1007/s13205-018-1324-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/18/2018] [Indexed: 12/18/2022] Open
Abstract
Microbial inoculant preparation is a prerequisite for its application in large-scale bioremediation. In the present study, Sphingomonas sp. DC-6, an efficient acetochlor-degrading strain, was used to investigate the process of preparing the inoculant. Optimization of submerged fermentation (SmF) by response surface methodology (RSM) resulted in a first 22% increase in biomass of liquid inoculant. Then, a biomass increase of 2.18 times with 14.58% shortened incubation period was further obtained in optimized medium using a 7.5-l bioreactor. However, less than 0.4% viable cells in liquid inoculant survived after 180-days storage. Thus, optimized spray drying conditions were subsequently employed for the production of high viability powder (2.11 × 1012 cfu g- 1 powder) without additive and its survival ratio (SR) after 180-days storage was still maintained at 90.5%. Both the 180-days stored powder and the original powder showed the same degradation performance, being able to completely degrade 200 mg l- 1 acetochlor within 48 h. This study demonstrated that strain DC-6 was suitable for industrial production of bacteria powder and provided a potential approach for the preparation of pesticide-degrading microbial inoculant.
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Affiliation(s)
- Hui Wang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Kun Jiang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Ziwei Zhu
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Wankui Jiang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Zhangong Yang
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Shijun Zhu
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Jiguo Qiu
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Xin Yan
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Jian He
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Qin He
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
| | - Qing Hong
- Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 People's Republic of China
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Comparative Transcriptome Analysis Reveals the Mechanism Underlying 3,5-Dibromo-4-Hydroxybenzoate Catabolism via a New Oxidative Decarboxylation Pathway. Appl Environ Microbiol 2018; 84:AEM.02467-17. [PMID: 29305508 DOI: 10.1128/aem.02467-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 12/13/2017] [Indexed: 02/07/2023] Open
Abstract
The compound 3,5-dibromo-4-hydroxybenzoate (DBHB) is both anthropogenically released into and naturally produced in the environment, and its environmental fate is of great concern. Aerobic and anaerobic reductive dehalogenations are the only two reported pathways for DBHB catabolism. In this study, a new oxidative decarboxylation pathway for DBHB catabolism was identified in a DBHB-utilizing strain, Pigmentiphaga sp. strain H8. The genetic determinants underlying this pathway were elucidated based on comparative transcriptome analysis and subsequent experimental validation. A gene cluster comprising orf420 to orf426, with transcripts that were about 33- to 4,400-fold upregulated in DBHB-induced cells compared with those in uninduced cells, was suspected to be involved in DBHB catabolism. The gene odcA (orf420), which is essential for the initial catabolism of DBHB, encodes a novel NAD(P)H-dependent flavin monooxygenase that mediates the oxidative decarboxylation of DBHB to 2,6-dibromohydroquinone (2,6-DBHQ). The substrate specificity of the purified OdcA indicated that the 4-hydroxyl group and its ortho-halogen(s) are important for hydroxylation of the C-1 site carboxyl group by OdcA. 2,6-DBHQ is then ring cleaved by the dioxygenase OdcB (Orf425) to 2-bromomaleylacetate, which is finally transformed to β-ketoadipate by the maleylacetate reductase OdcC (Orf426). These results provide a better understanding of the molecular mechanism underlying the catabolic diversity of halogenated para-hydroxybenzoates.IMPORTANCE Halogenated hydroxybenzoates (HBs), which are widely used synthetic precursors for chemical products and common metabolic intermediates from halogenated aromatics, exert considerable adverse effects on human health and ecological security. Microbial catabolism plays key roles in the dissipation of halogenated HBs in the environment. In this study, the discovery of a new catabolic pathway for 3,5-dibromo-4-hydroxybenzoate (DBHB) and clarification of the genetic determinants underlying the pathway broaden our knowledge of the catabolic diversity of halogenated HBs in microorganisms. Furthermore, the NAD(P)H-dependent flavin monooxygenase OdcA identified in Pigmentiphaga sp. strain H8 represents a novel 1-monooxygenase for halogenated para-HBs found in prokaryotes and enhances our knowledge of the decarboxylative hydroxylation of (halogenated) para-HBs.
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Li N, Yao L, He Q, Qiu J, Cheng D, Ding D, Tao Q, He J, Jiang J. 3,6-Dichlorosalicylate Catabolism Is Initiated by the DsmABC Cytochrome P450 Monooxygenase System in Rhizorhabdus dicambivorans Ndbn-20. Appl Environ Microbiol 2018; 84:e02133-17. [PMID: 29196293 PMCID: PMC5795090 DOI: 10.1128/aem.02133-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/28/2017] [Indexed: 11/20/2022] Open
Abstract
The degradation of the herbicide dicamba is initiated by demethylation to form 3,6-dichlorosalicylate (3,6-DCSA) in Rhizorhabdusdicambivorans Ndbn-20. In the present study, a 3,6-DCSA degradation-deficient mutant, Ndbn-20m, was screened. A cluster, dsmR1DABCEFGR2, was lost in this mutant. The cluster consisted of nine genes, all of which were apparently induced by 3,6-DCSA. DsmA shared 30 to 36% identity with the monooxygenase components of reported three-component cytochrome P450 systems and formed a monophyletic branch in the phylogenetic tree. DsmB and DsmC were most closely related to the reported [2Fe-2S] ferredoxin and ferredoxin reductase, respectively. The disruption of dsmA in strain Ndbn-20 resulted in inactive 3,6-DCSA degradation. When dsmABC, but not dsmA alone, was introduced into mutant Ndbn-20m and Sphingobium quisquiliarum DC-2 (which is unable to degrade salicylate and its derivatives), they acquired the ability to hydroxylate 3,6-DCSA. Single-crystal X-ray diffraction demonstrated that the DsmABC-catalyzed hydroxylation occurred at the C-5 position of 3,6-DCSA, generating 3,6-dichlorogentisate (3,6-DCGA). In addition, DsmD shared 51% identity with GtdA (a gentisate and 3,6-DCGA 1,2-dioxygenase) from Sphingomonas sp. strain RW5. However, unlike GtdA, the purified DsmD catalyzed the cleavage of gentisate and 3-chlorogentisate but not 6-chlorogentisate or 3,6-DCGA in vitro Based on the bioinformatic analysis and gene function studies, a possible catabolic pathway of dicamba in R. dicambivorans Ndbn-20 was proposed.IMPORTANCE Dicamba is widely used to control a variety of broadleaf weeds and is a promising target herbicide for the engineering of herbicide-resistant crops. The catabolism of dicamba has thus received increasing attention. Bacteria mineralize dicamba initially via demethylation, generating 3,6-dichlorosalicylate. However, the catabolism of 3,6-dichlorosalicylate remains unknown. In this study, we cloned a gene cluster, dsmR1DABCEFGR2, involved in 3,6-dichlorosalicylate degradation from R. dicambivorans Ndbn-20, demonstrated that the cytochrome P450 monooxygenase system DsmABC was responsible for the 5-hydroxylation of 3,6-dichlorosalicylate, and proposed a dicamba catabolic pathway. This study provides a basis to elucidate the catabolism of dicamba and has benefits for the ecotoxicological study of dicamba. Furthermore, the hydroxylation of salicylate has been previously reported to be catalyzed by single-component flavoprotein or three-component Rieske non-heme iron oxygenase, whereas DsmABC was the only cytochrome P450 monooxygenase system hydroxylating salicylate and its methyl- or chloro-substituted derivatives.
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Affiliation(s)
- Na Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Li Yao
- School of Marine and Biological Engineering, Yancheng Teachers University, Yancheng, Jiangsu, China
| | - Qin He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jiguo Qiu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Dan Cheng
- Laboratory Centre of Life Science, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Derong Ding
- Beijing DBN Biotech Co., Ltd., Beijing, China
| | - Qing Tao
- Beijing DBN Biotech Co., Ltd., Beijing, China
| | - Jian He
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
- Laboratory Centre of Life Science, College of Life Science, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jiandong Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China
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