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Shah SB, Wang Y, Anwar N, Abbas SZ, Khan KA, Wang SM, Ullah MW. Co-metabolic degradation and metabolite detection of hexabromocyclododecane by Shewanella oneidensis MR-1. Appl Microbiol Biotechnol 2024; 108:25. [PMID: 38157005 DOI: 10.1007/s00253-023-12905-6] [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: 07/10/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 01/03/2024]
Abstract
Hexabromocyclododecane (HBCD) is a widely used brominated flame retardant; however, it is a persistent organic pollutant as well as affects the human thyroid hormones and causes cancer. However, the degradation of HBCD has received little attention from researchers. Due to its bioaccumulative and hazardous properties, an appropriate strategy for its remediation is required. In this study, we investigated the biodegradation of HBCD using Shewanella oneidensis MR-1 under optimized conditions. The Box-Behnken design (BBD) was implemented for the optimization of the physical degradation parameters of HBCD. S. oneidensis MR-1 showed the best degradation performance at a temperature of 30 °C, pH 7, and agitation speed of 115 rpm, with an HBCD concentration of 1125 μg/L in mineral salt medium (MSM). The strain tolerated up to 2000 μg/L HBCD. Gas chromatography-mass spectrometry analysis identified three intermediates, including 2-bromo dodecane, 2,7,10-trimethyldodecane, and 4-methyl-1-decene. The results provide an insightful understanding of the biodegradation of HBCD by S. oneidensis MR-1 under optimized conditions and could pave the way for further eco-friendly applications. KEY POINTS: • HBCD biodegradation by Shewanella oneidensis • Optimization of HBCD biodegradation by the Box-Behnken analysis • Identification of useful metabolites from HBCD degradation.
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Affiliation(s)
- Syed Bilal Shah
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Yiting Wang
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Naveed Anwar
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Syed Zaghum Abbas
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Khalid Ali Khan
- Applied College, Mahala Campus and the Unit of Bee Research and Honey Production/Research Center for Advanced Materials Science (RCAMS), King Khalid University, P.O. Box 9004, Abha, 61413, Saudi Arabia
| | - Song-Mei Wang
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
| | - Muhammad Wajid Ullah
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
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2
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Zhang M, Shi J, Li B, Ge H, Tao H, Zhang J, Li X, Cai Z. Thyroid Hormone Receptor Agonistic and Antagonistic Activity of Newly Synthesized Dihydroxylated Polybrominated Diphenyl Ethers: An In Vitro and In Silico Coactivator Recruitment Study. TOXICS 2024; 12:281. [PMID: 38668504 PMCID: PMC11053510 DOI: 10.3390/toxics12040281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/20/2024] [Accepted: 03/28/2024] [Indexed: 04/29/2024]
Abstract
Dihydroxylated polybrominated diphenyl ethers (DiOH-PBDEs) could be the metabolites of PBDEs of some organisms or the natural products of certain marine bacteria and algae. OH-PBDEs may demonstrate binding affinity to thyroid hormone receptors (TRs) and can disrupt the functioning of the systems modulated by TRs. However, the thyroid hormone disruption mechanism of diOH-PBDEs remains elusive due to the absence of diOH-PBDEs standards. This investigation explores the potential disruptive effects of OH/diOH-PBDEs on thyroid hormones via competitive binding and coactivator recruitment with TRα and TRβ. At levels of 5000 nM and 25,000 nM, 6-OH-BDE-47 demonstrated significant recruitment of steroid receptor coactivator (SRC), whereas none of the diOH-PBDEs exhibited SRC recruitment within the range of 0.32-25,000 nM. AutoDock CrankPep (ADCP) simulations suggest that the conformation of SRC and TR-ligand complexes, particularly their interaction with Helix 12, rather than binding affinity, plays a pivotal role in ligand agonistic activity. 6,6'-diOH-BDE-47 displayed antagonistic activity towards both TRα and TRβ, while the antagonism of 3,5-diOH-BDE-100 for TRα and TRβ was concentration-dependent. 3,5-diOH-BDE-17 and 3,5-diOH-BDE-51 exhibited no discernible agonistic or antagonistic activities. Molecular docking analysis revealed that the binding energy of 3,3',5-triiodo-L-thyronine (T3) surpassed that of OH/diOH-PBDEs. 3,5-diOH-BDE-100 exhibited the highest binding energy, whereas 6,6'-diOH-BDE-47 displayed the lowest. These findings suggest that the structural determinants influencing the agonistic and antagonistic activities of halogen phenols may be more intricate than previously proposed, involving factors beyond high-brominated PBDEs or hydroxyl group and bromine substitutions. It is likely that the agonistic or antagonistic propensities of OH/diOH-PBDEs are instigated by protein conformational changes rather than considerations of binding energy.
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Affiliation(s)
- Mengtao Zhang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; (M.Z.); (H.G.); (H.T.); (J.Z.)
- China State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China;
- Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (B.L.); (X.L.)
| | - Jianghong Shi
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; (M.Z.); (H.G.); (H.T.); (J.Z.)
| | - Bing Li
- Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (B.L.); (X.L.)
| | - Hui Ge
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; (M.Z.); (H.G.); (H.T.); (J.Z.)
| | - Huanyu Tao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; (M.Z.); (H.G.); (H.T.); (J.Z.)
| | - Jiawei Zhang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; (M.Z.); (H.G.); (H.T.); (J.Z.)
| | - Xiaoyan Li
- Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; (B.L.); (X.L.)
| | - Zongwei Cai
- China State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China;
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Huang X, Xu K, Lyu L, Ding C, Zhao Y, Wang X. Identification and yield of metabolites of chlorinated paraffins incubated with chicken liver microsomes: Assessment of their potential to convert into metabolites. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131640. [PMID: 37201278 DOI: 10.1016/j.jhazmat.2023.131640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/11/2023] [Accepted: 05/12/2023] [Indexed: 05/20/2023]
Abstract
Chlorinated paraffins (CPs) are emerging environmental pollutants. Although metabolism has been shown to affect the differential accumulation of short-chain (SCCPs), medium-chain (MCCPs) and long-chain (LCCPs) CPs in birds, CP metabolites have rarely been reported and the extent to which they are formed is still unclear. In this study, single and mixed CP standards were incubated with chicken liver microsomes in vitro to study the generation of CP metabolites. Putative aldehyde/ketone and carboxylic acid metabolites identified by mass spectroscopy data were shown to be false positive results. Phase I metabolism of CPs first formed monohydroxylated ([M-Cl+OH]) and then dihydroxylated ([M-2Cl+2OH]) products. The yields of monohydroxylated metabolites of CPs decreased with increasing carbon chain length and chlorine content at the initial stage of reaction. Notably, the yield of monohydroxylated metabolites of SCCPs with 51.5% Cl content reached 21%, and that of 1,2,5,6,9,10-hexachlorodecane (C10H16Cl6) was as high as 71%. Thus, monohydroxy metabolites of CPs in birds should not be ignored, especially those of SCCPs. This study provides important data that could support improvements to the ecological/health risk assessment of CPs.
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Affiliation(s)
- Xiaomei Huang
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
| | - Kaihang Xu
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
| | - Lina Lyu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Chenhong Ding
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
| | - Yarong Zhao
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
| | - Xu Wang
- Institute of Quality Standard and Monitoring Technology for Agro-Products, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-Products, Guangzhou 510640, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China.
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Yang SW, Gu SX, Tang B, Dang Y, Xu RF, Luo WK, Zheng J, Ren MZ, Yu YJ. Tissue-specific and stereoselective accumulation of Dechlorane Plus isomers in two predator fish in a laboratory feeding study. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 249:114469. [PMID: 38321685 DOI: 10.1016/j.ecoenv.2022.114469] [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: 06/09/2022] [Revised: 12/20/2022] [Accepted: 12/23/2022] [Indexed: 02/08/2024]
Abstract
The tissue-specific bioaccumulation of Dechlorane Plus (DP) isomers was investigated in two predator fish species (redtail catfish, RF; and oscar fish, OF) that were feeding on tiger barb (TB), which was exposed to syn-DP and anti-DP isomers. The biotransformation potential of DP isomers was examined by in vitro metabolism using fish liver microsomes. No difference in accumulation behaviors of DP isomers was observed between RF and OF, and the accumulation of both syn- and anti-DP isomers exhibiting a linear increase trend with the exposure time in all fish tissues. The assimilation efficiencies and depuration rates for syn-DP and anti-DP were determined to be the highest in the liver. Biomagnification factors (BMFs) for both syn-DP and anti-DP were higher than one in the serum and gastrointestinal tract of fish, whereas were less than one in the other tissues. The wet-weight concentrations of DP isomers in tissues were significantly correlated with the lipid contents in both fish species, indicating that the tissue distribution of DP isomers occurred through passive diffusion to the lipid compartments in vivo. Tissue-specific compositions of DP isomers were observed, with anti-DP selectively accumulating in the liver, gonad, serum, and gills, whilst syn-DP in the carcass and GI tract. However, after being normalized of all tissues, the fish showed no selective accumulation of DP isomers during the exposure period, and selective accumulation of syn-DP was observed during the depuration period. No potential DP metabolites were detected in the fish tissues and in vitro metabolism systems. The main cause of this stereoselective DP isomer accumulation could have been the selective excretion of anti-DP isomer through the fish feces.
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Affiliation(s)
- Shui-Wen Yang
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; Chongqing Solid Wastes Management Center, Chongqing 401147, PR China
| | - Shun-Xi Gu
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China; School of Public Health, Key Laboratory of Environmental Pollution and Disease Monitoring of Ministry of Education, Guizhou Medical University, Guiyang 550000, PR China
| | - Bin Tang
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China.
| | - Yao Dang
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China
| | - Rong-Fa Xu
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China.
| | - Wei-Keng Luo
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China
| | - Jing Zheng
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China; School of Public Health, Key Laboratory of Environmental Pollution and Disease Monitoring of Ministry of Education, Guizhou Medical University, Guiyang 550000, PR China
| | - Ming-Zhong Ren
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China
| | - Yun-Jiang Yu
- State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, Research Group of Emerging Contaminants, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, PR China
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5
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Wang R, Zhao W, Cui N, Dong S, Su X, Liang H, Zhang N, Song Z, Tian F, Wang P. Comparative In Vitro and In Vivo Hydroxylation Metabolization of Polychlorinated Biphenyl 101 in Laying Hens: A Pilot Study. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:7279-7287. [PMID: 35649149 DOI: 10.1021/acs.jafc.2c01462] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Polychlorinated biphenyls (PCBs) can be metabolized into hydroxylated PCBs (OH-PCBs) that exhibit greater toxicity than their parent compounds. In particular, 2,2',4,5,5'-pentachlorobiphenyl (PCB 101) is commonly found in chicken feeds and breeding environments, although information on the biotransformation of this PCB in chickens is lacking. In this study, the hydroxylation metabolization of PCB 101 was assessed based on in vitro trials with Sanhuang chicken liver microsomes and in vivo experiments with Hy-Line Brown hens. The para-substituted metabolite 4'-OH-PCB 101 is the predominant metabolite of PCB 101. 4'-OH-PCB 101 is preferentially retained in the chicken bloodstream and partly distributed into different tissues of laying hens. The blood-brain barrier can effectively prevent the OH-PCB from entering the brain, and the adipose tissue contains a relatively low residue concentration of the OH-PCB. The laying hen can deplete the OH-PCB via laying eggs and excrement. The ratio of 4'-OH-PCB 101/PCB 101 in egg yolk is about 1:2. These results first provide definite evidence for the previous hypothesis of the PCB 101 metabolism by chickens. They could assist in predicting the environmental fate of PCBs, and in the risk assessment of PCBs and OH-PCBs in chicken-based foodstuffs.
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Affiliation(s)
- Ruiguo Wang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 10081, China
| | - Wenyu Zhao
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 10081, China
| | - Na Cui
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 10081, China
| | - Shujun Dong
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 10081, China
| | - Xiaoou Su
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 10081, China
| | - Haijun Liang
- CHINA FEED Magazine Agency, Beijing 100710, China
| | - Na Zhang
- National Animal Husbandry Service, Beijing 100125, China
| | - Zhichao Song
- Henan Provincial Institute of Veterinary Drug Control, Zhengzhou 450008, China
| | - Feifei Tian
- Shimadzu China Co., Ltd., Beijing 100020, China
| | - Peilong Wang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 10081, China
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6
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Smythe TA, Su G, Bergman Å, Letcher RJ. Metabolic transformation of environmentally-relevant brominated flame retardants in Fauna: A review. ENVIRONMENT INTERNATIONAL 2022; 161:107097. [PMID: 35134713 DOI: 10.1016/j.envint.2022.107097] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Over the past few decades, production trends of the flame retardant (FR) industry, and specifically for brominated FRs (BFRs), is for the replacement of banned and regulated compounds with more highly brominated, higher molecular weight compounds including oligomeric and polymeric compounds. Chemical, biological, and environmental stability of BFRs has received some attention over the years but knowledge is currently lacking in the transformation potential and metabolism of replacement emerging or novel BFRs (E/NBFRs). For articles published since 2015, a systematic search strategy reviewed the existing literature on the direct (e.g., in vitro or in vivo) non-human BFR metabolism in fauna (animals). Of the 51 papers reviewed, and of the 75 known environmental BFRs, PBDEs were by far the most widely studied, followed by HBCDDs and TBBPA. Experimental protocols between studies showed large disparities in exposure or incubation times, age, sex, depuration periods, and of the absence of active controls used in in vitro experiments. Species selection emphasized non-standard test animals and/or field-collected animals making comparisons difficult. For in vitro studies, confounding variables were generally not taken into consideration (e.g., season and time of day of collection, pollution point-sources or human settlements). As of 2021 there remains essentially no information on the fate and metabolic pathways or kinetics for 30 of the 75 environmentally relevant E/BFRs. Regardless, there are clear species-specific and BFR-specific differences in metabolism and metabolite formation (e.g. BDE congeners and HBCDD isomers). Future in vitro and in vivo metabolism/biotransformation research on E/NBFRs is required to better understand their bioaccumulation and fate in exposed organisms. Also, studies should be conducted on well characterized lab (e.g., laboratory rodents, zebrafish) and commonly collected wildlife species used as captive models (crucian carp, Japanese quail, zebra finches and polar bears).
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Affiliation(s)
- Tristan A Smythe
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
| | - Guanyong Su
- School of Environmental Science and Engineering, Nanjing University of Science and Technology, Nanjing, China
| | - Åke Bergman
- Department of Analytical Chemistry and Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Wildlife and Landscape Directorate, Science and Technology Branch, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON, Canada; Department of Chemistry, Carleton University, Ottawa, ON K1S 5B6, Canada.
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Yokota K, Matsuzawa Y, Fukuda S, Takada H, Mizukawa K. Species-specific debromination of BDE99 in teleost fish: The relationship between debromination ability and bioaccumulation patterns of PBDEs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151265. [PMID: 34715229 DOI: 10.1016/j.scitotenv.2021.151265] [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] [Received: 07/28/2021] [Revised: 10/14/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are known to be broken down by debromination reactions in the natural environment, such as by photolysis, microbial and metabolic processes. Although species-specific debromination of PBDEs by fish has also been reported, it has only rarely been studied from the phylogenetic perspective. The objective of this study is to reveal the factors affecting species-specific debromination through validation between the bioaccumulation of PBDEs in muscle tissue and the ability to debrominate BDE99. As environmental observations, PBDE concentrations in muscle tissues were analyzed in 25 wild fish (Cyprinidae, Gobiidae and others). As in vitro experiments, debromination experiments were conducted using the hepatic microsomes of 21 fish species. Significant amounts of BDE99 were detected in almost none of the Cyprinidae. A relatively higher debromination ability was confirmed in the Cyprinidae in in vitro experiments. The Cyprinidae thus appears to be a family with high debromination ability. BDE99 has been detected in some goby species but not others. This pattern was also seen in in vitro experiments, suggesting that debromination ability is not consistent within the Gobiidae. In further quantitative comparisons, kinetic parameters such as Km and vmax were determined for selected fish species. The common carp (Cyprinus carpio) and the Japanese crucian carp (Carassius cuvieri), both Cyprinidae, showed higher vmax values, whereas vmax values among three Gobiidae diverged widely. A comparison of field observations and in vitro experiments, revealed the bioaccumulation ratio of BDE99 to be affected by the BDE99 debromination ability of each fish species. This is the first report on classification of BDE99 accumulation ratio by debromination ability and a phylogenetic species comparison based on kinetic parameters for debromination reactions of PBDEs by fish.
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Affiliation(s)
- Kazuya Yokota
- Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, 3-5-8, Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Yuki Matsuzawa
- Aqua Restoration Research Center, Public Works Research Institute, National Research and Development Agency, Kawashima Kasada-machi, Kakamigahara, Gifu 501-6021, Japan; United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
| | - Shinji Fukuda
- Laboratory of Water Resources Planning, Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8, Saiwaicho, Fuchu, Tokyo 183-8509, Japan.
| | - Hideshige Takada
- Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, 3-5-8, Saiwaicho, Fuchu, Tokyo 183-8509, Japan.
| | - Kaoruko Mizukawa
- Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, 3-5-8, Saiwaicho, Fuchu, Tokyo 183-8509, Japan.
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Yu YJ, Li ZR, Zhu Y, Li LZ, Zhang LH, Xiang MD, Zeng EY. Significance of biotransformation and excretion on the enantioselective bioaccumulation of hexabromocyclododecane (HBCDD) in laying hens and developing chicken embryos. JOURNAL OF HAZARDOUS MATERIALS 2022; 422:126749. [PMID: 34390953 DOI: 10.1016/j.jhazmat.2021.126749] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/07/2021] [Accepted: 07/24/2021] [Indexed: 06/13/2023]
Abstract
Although (-)-α-hexabromocyclododecane (HBCDD) and (+)-γ-HBCDD are preferentially enriched in chickens, the key factors contributing to their selective bioaccumulation in hens and their potential biotransformation in developing chicken embryos remain unclear. Herein, in vivo and in ovo exposure experiments using hens and fertilized eggs were conducted to investigate the absorption, excretion, and biotransformation of HBCDDs in chickens. γ-HBCDD (76%) exhibited a higher absorption efficiency than α- (22%) and β- (69%) HBCDDs. However, α-HBCDD was dominant in hen tissues, although γ-HBCDD accounted for >75% in the spiked feed. Moreover, chicken embryos biotransformed approximately 9.5% and 11.7% of absorbed α- and γ-HBCDDs, respectively, implying that diastereomer-selective elimination causes the predominance of α-HBCDD in hens. The concentration and enantiomer fraction (EF) of α-HBCDD in laid eggs were significantly positively correlated, suggesting enantioselective elimination. The EFs of α- and γ-HBCDDs varied between feces from the exposure and depuration periods, indicating the preferred excretion of (+)-α- and (-)-γ-HBCDDs. Furthermore, the enantioselective biotransformation of (-)-γ-HBCDD was confirmed in developing chicken embryos. These results show that excretion and biotransformation contribute to the diastereomer- and enantiomer-selective bioaccumulation of HBCDDs in chickens; The results may improve our understanding of the environmental fate and ecological risks of HBCDDs in biota.
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Affiliation(s)
- Yun-Jiang Yu
- State Environmental Protection Key Laboratory of Environmental Health Risk Assessment, South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Zong-Rui Li
- State Environmental Protection Key Laboratory of Environmental Health Risk Assessment, South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510655, China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
| | - Yu Zhu
- State Environmental Protection Key Laboratory of Environmental Health Risk Assessment, South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510655, China; School of Environmental and Chemical Engineering, Xi' an Polytechnic University, Xi' an 710048, China
| | - Liang-Zhong Li
- State Environmental Protection Key Laboratory of Environmental Health Risk Assessment, South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Luo-Hong Zhang
- School of Environmental and Chemical Engineering, Xi' an Polytechnic University, Xi' an 710048, China
| | - Ming-Deng Xiang
- State Environmental Protection Key Laboratory of Environmental Health Risk Assessment, South China Institute of Environmental Science, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Eddy Y Zeng
- School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
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Hexabromocyclododecanes Are Dehalogenated by CYP168A1 from Pseudomonas aeruginosa Strain HS9. Appl Environ Microbiol 2021; 87:e0082621. [PMID: 34132585 DOI: 10.1128/aem.00826-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hexabromocyclododecanes (HBCDs) are widely used brominated flame retardants that cause antidiuretic hormone syndrome and even induce cancer. However, little information is available about the degradation mechanisms of HBCDs. In this study, genomic and proteomic analyses, reverse transcription-quantitative PCR, and gene knockout assays reveal that a cytochrome P450-encoding gene is responsible for HBCD catabolism in Pseudomonas aeruginosa HS9. The CO difference spectrum of the enzyme CYP168A1 was matched to P450 characteristics via UV visibility. We demonstrate that the reactions of debromination and hydrogenation are carried out one after another based on detection of the metabolites pentabromocyclododecanols (PBCDOHs), tetrabromocyclododecadiols (TBCDDOHs), and bromide ion. In the 18O isotope experiments, PBCD18OHs were only detected in the H218O group, proving that the added oxygen is derived from H2O, not from O2. This study elucidates the degradation mechanism of HBCDs by Pseudomonas. IMPORTANCE Hexabromocyclododecanes (HBCDs) are environmental pollutants that are widely used in industry. In this study, we identified and characterized a novel key dehalogenase, CYP168A1, that is responsible for HBCD degradation from Pseudomonas aeruginosa strain HS9. This study provides new insights into understanding biodegradation of HBCDs.
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Wang XS, Tan X, Zhang Y, Hu XX, Shen C, Huang YY, Fu HL, Yu RH, He CT. The enantiomer-selective metabolism of hexabromocyclododecanes (HBCDs) by human HepG2 cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 768:144430. [PMID: 33736337 DOI: 10.1016/j.scitotenv.2020.144430] [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: 10/09/2020] [Revised: 12/06/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Although hepatic metabolism of hexabromocyclododecanes (HBCDs) played critical roles in the selective bioaccumulation of HBCDs in humans, the hepatic metabolism patterns of its enantiomers remained ambiguous. Aiming to elucidate the mechanism on hepatic metabolism of hexabromocyclododecanes (HBCDs) enantiomers, the enantiomers ((+)-α-HBCD, (-)-α-HBCD, (+)-γ-HBCD, and (-)-γ-HBCD), the diastereoisomers (α-, β-, and γ-HBCDs) and the mixed of α- and γ-HBCDs were incubated with human HepG2 cell under different exposure levels in the present study. The clearance percentages ranked as γ-HBCD enantiomers >β-HBCD enantiomers >α-HBCD enantiomers at the same exposure levels. The clearance percentages of (+)- and (-)-α-HBCDs increased when cells were exposed to racemic α-HBCD and the mixture of racemic α- and γ-HBCDs (p < 0.05). (-)-γ-HBCD was more resistant to human hepatic metabolism than (+)-γ-HBCD, leading to the enantiomer fractions (EFs) of γ-HBCD lower than 0.50. (-)-α-HBCD was slightly more metabolized when independently exposed to α-HBCD, while (+)-α-HBCD was more preferentially metabolized after exposure to α- and γ-HBCD mixtures. Hydroxylation and debromination HBCD metabolites were identified. In addition, the different EFs of HBCDs in cells and mediums suggested the selective transfer of chiral HBCDs and HBCD metabolites through the cell membrane. This study provided new insight into the enantiomer-selective metabolism of HBCDs.
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Affiliation(s)
- Xue-Song Wang
- School of Agriculture, Sun Yat-sen University, Guangzhou 510275, China; Guangdong Provincial Key Laboratory of Emergency Test for Dangerous Chemicals, China National Analytical Center Guangzhou (Guangdong Institute of Analysis), Guangdong Academy of Sciences, 100 Xianlie Middle Road, Guangzhou 510070, China
| | - Xiao Tan
- School of Agriculture, Sun Yat-sen University, Guangzhou 510275, China
| | - Yan Zhang
- School of Life Science, Sun Yat-sen University, Guangzhou 510275, China
| | - Xia-Xin Hu
- School of Agriculture, Sun Yat-sen University, Guangzhou 510275, China
| | - Chuang Shen
- School of Safety and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Ying-Ying Huang
- School of Safety and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Hui-Ling Fu
- School of Safety and Environmental Engineering, Hunan Institute of Technology, Hengyang 421002, China
| | - Ruo-Han Yu
- School of Life Science, Sun Yat-sen University, Guangzhou 510275, China
| | - Chun-Tao He
- School of Agriculture, Sun Yat-sen University, Guangzhou 510275, China.
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Folle NMT, Azevedo-Linhares M, Garcia JRE, Esquivel L, Grotzner SR, Oliveira ECD, Filipak Neto F, Oliveira Ribeiro CAD. 2,4,6-Tribromophenol is toxic to Oreochromis niloticus (Linnaeus, 1758) after trophic and subchronic exposure. CHEMOSPHERE 2021; 268:128785. [PMID: 33168290 DOI: 10.1016/j.chemosphere.2020.128785] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/21/2020] [Accepted: 10/25/2020] [Indexed: 06/11/2023]
Abstract
The presence of 2,4,6-Tribromophenol (TBP) in the environment increased the risk of exposure to aquatic organisms affecting the animal development or metabolism. The current study investigated the low, subchronic and trophic effect of TBP in both, male and female adult of Oreochromis niloticus. The fish were exposed to 0.5 or 50 ng g-1 of TBP every ten days for 70 days. Then, hepatosomatic (HSI) and gonadosomatic (GSI) indexes, erythrocyte parameters (hemoglobin content, nuclear morphology and morphometrical abnormalities), biochemical endpoints (glutathione S-Transferase and catalase activities, non-protein thiols, lipid peroxidation and protein carbonylation levels in the liver; and acetylcholinesterase activity in the brain and muscle), histopathological analysis (liver) and vitellogenin levels (plasma) were considered. TBP affected the HSI in male and female fish, but not the GSI. Principal Component Analysis revealed that erythrocytes from males are more sensitive to TBP exposure. Likewise, TBP induced the expression of vitellogenin, CAT activity and liver lesion in male fish comparatively with control group, but GST and NPT were influenced only by sex. Finally, the results showed that the antioxidant mechanism and cholinesterase activity effects were more pronounced in male than in female. The current data shows evidences of estrogenic endocrine disruption and toxicity in O. niloticus exposed to TBP, revealing the risk of exposure to biota.
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Affiliation(s)
- Nilce Mary Turcatti Folle
- Departamento de Biologia Celular, Universidade Federal Do Paraná, Caixa Postal 19031, CEP 81531-970, Curitiba-PR, Brazil
| | - Maristela Azevedo-Linhares
- Centro de Tecnologia Em Saúde e Meio Ambiente, Instituto de Tecnologia Do Paraná, CEP 81350-010, Curitiba, PR, Brazil
| | | | - Luíse Esquivel
- Estação de Piscicultura Panamá, Est. Geral Bom Retiro. Paulo Lopes - SC, CEP 88490-000, Brazil
| | - Sonia Regina Grotzner
- Departamento de Biologia Celular, Universidade Federal Do Paraná, Caixa Postal 19031, CEP 81531-970, Curitiba-PR, Brazil
| | - Elton Celton de Oliveira
- Universidade Tecnológica Federal Do Paraná. Campus Dois Vizinhos, CEP 82660-000, Dois Vizinhos, PR. Brazil
| | - Francisco Filipak Neto
- Departamento de Biologia Celular, Universidade Federal Do Paraná, Caixa Postal 19031, CEP 81531-970, Curitiba-PR, Brazil
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Li ZR, Luo XJ, Lin L, Zeng YH, Mai BX. Effect of laying sequence and selection of maternal tissues in assessment of maternal transfer of organohalogenated contaminants during chicken egg formation: A pilot study. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 270:116157. [PMID: 33321435 DOI: 10.1016/j.envpol.2020.116157] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Many studies have reported maternal transfer of organic contaminants in oviparous species, with inconsonant results. Egg-laying sequence and selected maternal tissues may impact on assessment of potential maternal transfer of contaminants. Here, this hypothesis was verified by exposing chickens (Gallus domesticus) to polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DPs). Concentrations in eggs laid during exposure exhibited periodic fluctuations (conforming to egg-laying cycles) and a decreasing trend during depuration. Fluctuation patterns of DPs and BDE209 differed from those of other compounds. The PBDE congener profiles in eggs were dominated by BDE209 during exposure and by BDE100 and 153 during depuration. The abundance of PCB congener (CB138) which is recalcitrant to metabolism increased with laying sequence. Maternal transfer potential was negatively correlated (P = 0.0014, R2 = 0.7874) to the log KOW of chemicals (log KOW >7) when the muscle, heart, lung, or stomach was used. No correlations were found when the liver, fat, kidneys, or intestine was used (log KOW >7), although DPs and BDE209 showed the highest maternal transfer potential. Different fluctuation patterns of DPs and BDE209 in eggs and increased abundance of BDE209 in eggs laid in the initial egg-laying period imply that the liver, fat, kidney, or intestinal tissues could be more appropriate in assessing maternal transfer of the target analytes.
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Affiliation(s)
- Zong-Rui Li
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, 510655, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Jun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
| | - Lan Lin
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan-Hong Zeng
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Bi-Xian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
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de Wit CA, Johansson AK, Sellström U, Lindberg P. Mass balance study of brominated flame retardants in female captive peregrine falcons. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1115-1131. [PMID: 31237594 DOI: 10.1039/c9em00177h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Little is known about brominated flame retardant (BFR) dynamics in birds, especially large molecules such as decabromodiphenyl ether (BDE-209). In particular, bioaccumulation from food and transfer dynamics to eggs are poorly understood. Therefore, an input-output mass balance study of tri-decaBDEs, DBDPE and HBCDD was performed in three female peregrine falcons from a captive breeding program by analyzing their naturally contaminated food (quail, chicken (cockerels)), plasma, feces and eggs. Predominant BFRs in cockerels and quail were BDE-209 and DBDPE, as well as HBCDD in quail. The predominant BFRs found in falcon plasma were BDE-209, -153 and -183, in eggs, HBCDD, BDE-209 and -153 and in feces, BDE-209. Mean absorption efficiencies (AE) for the tetra-octabrominated BDEs ranged from 84-100% and 70% for HBCDD. The AEs for BDE-206, -207, -208 and -209 varied due to the large variability seen for feces fluxes. All egg/plasma ratios for BDEs were similar and greater than one (range 1.1-2.7), including for BDE-209, indicating efficient transfer from females to the eggs. Excretion via egg-laying was approximately 6.0-29% of the initial, pre-breeding body burden of individual penta-decaBDE congeners, (15-45% for BDE-206). HBCDD was not detected in plasma but was found in eggs, also indicating efficient transfer and excretion via eggs. Input fluxes from food exceeded the output fluxes (feces, eggs) indicating considerable metabolism for tetra-octaBDEs, possibly also for the nona-decaBDEs and HBCDD. Bioaccumulation factors calculated from lipid weight concentrations in plasma and food (BAFp) were highest for BDE-208 (31), -153 (23), -209 (19) and -207 (16) and from eggs and food (BAFe), were highest for HBCDD (140), BDE-153 (41), -208 (42), BDE-207 (24) and BDE-209 (21). BAFe and BAFp values were below 10 for BDE-47, -99 and -100. For one falcon, egg results were available from three different years and estimated half-lives were 65 d (BDE-99), 624 d (BDE-153), 31 d (BDE-154), 349 d (BDE-183), 77 d (BDE-196) and 89 d (BDE-197).
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Affiliation(s)
- Cynthia A de Wit
- Department of Environmental Science and Analytical Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Anna-Karin Johansson
- Department of Environmental Science and Analytical Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Ulla Sellström
- Department of Environmental Science and Analytical Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Peter Lindberg
- Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30 Göteborg, Sweden
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Huang H, Wang D, Wen B, Lv J, Zhang S. Roles of maize cytochrome P450 (CYP) enzymes in stereo-selective metabolism of hexabromocyclododecanes (HBCDs) as evidenced by in vitro degradation, biological response and in silico studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 656:364-372. [PMID: 30513427 DOI: 10.1016/j.scitotenv.2018.11.351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 06/09/2023]
Abstract
In vitro biotransformation of HBCDs by maize cytochrome P450 (CYP) enzymes, responses of CYPs to HBCDs at protein and transcription levels, and in silico simulation of interactions between CYPs and HBCDs were investigated in order to elucidate the roles of CYPs in the metabolism of HBCDs in maize. The results showed that degradation reactions of HBCDs by maize microsomal CYPs followed the first-order kinetics and were stereo-selective, with the metabolic rates following the order (-)γ- > (+)γ- > (+)α- > (-)α-HBCD. The hydroxylated metabolites OH-HBCDs, OH-PBCDs and OH-TBCDs were detected. (+)/(-)-α-HBCDs significantly decreased maize CYP protein content and inhibited CYP enzyme activity, whereas (+)/(-)-γ-HBCDs had obvious effects on the induction of CYPs. HBCDs selectively mediated the gene expression of maize CYPs, including the isoforms of CYP71C3v2, CYP71C1, CYP81A1, CYP92A1 and CYP97A16. Molecular docking results suggested that HBCDs could bind with these five CYPs, with binding affinity following the order CYP71C3v2 < CYP81A1 < CYP97A16 < CYP92A1 < CYP71C1. The shortest distances between the Br-unsubstituted C atom of HBCD isomers and the iron atom of heme in CYPs were 4.18-11.7 Å, with only the distances for CYP71C3v2 being shorter than 6 Å (4.61-5.38 Å). These results suggested that CYP71C3v2 was an efficient catalyst for degradation of HBCDs. For (+)α- and (-)γ-HBCDs, their binding affinities to CYPs were lower and the distances to the iron atom of heme in CYPs were shorter than their corresponding antipodes, consistent with the in vitro experimental results showing that they had shorter half-lives and were more easily hydroxylated. This study provides solid evidence for the roles of maize CYPs in the metabolism of HBCDs, and gives insight into the molecular mechanisms of the enantio-selective metabolism of HBCDs by plant CYPs.
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Affiliation(s)
- Honglin Huang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China
| | - Dan Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bei Wen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China
| | - Jitao Lv
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China
| | - Shuzhen Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Luo YL, Luo XJ, Ye MX, Lin L, Zeng YH, Mai BX. Species-specific debromination of polybromodiphenyl ethers determined by deiodinase activity in fish. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:710-716. [PMID: 30616061 DOI: 10.1016/j.envpol.2018.12.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
A combination of previous studies and the present study indicated species-specific debromination of polybromodiphenyl ethers (PBDEs) in teleost fish. Three situations of debromination were found, namely rapid debromination represented by debromination of BDE 99 to BDE 47 observed in common carp, tilapia, crucian carp, and oscar fish; slow debromination represented by debromination of BDE 99 to BDE 49 observed in the abovementioned fish and rainbow trout, salmon, and snakehead; and no or minor debromination observed in catfish. The results of experiments on cofactors, inhibitors, and substrate competitors indicated that activities of outer ring deiodinase of 3, 3', 5'-triiodothyronine (type I deiodinase), which cannot be inhibited by 6-propyl-2-thiouracil, were responsible for the rapid debromination, and the outer ring deiodinase of thyroxine (type II deiodinase) regulated the slow debromination. The debromination of BDE 99 to BDE 49 was more common, but occurred at a much lower rate (approximately 100 times lower) than the debromination of BDE 99 to BDE 47. This was because the activity of type II deiodinase was nearly two orders of magnitude lower than that of type I deiodinase in the fish species studied. Further studies on debromination of PBDEs and properties of deiodinase in more species are needed to confirm the hypothesis.
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Affiliation(s)
- Yuan-Lai Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; College of Life Sciences and Environment, Hengyang Normal University, Hengyang, 421008, China
| | - Xiao-Jun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
| | - Mei-Xia Ye
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lan Lin
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan-Hong Zeng
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Bi-Xian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
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Transformation Products of Organic Contaminants and Residues-Overview of Current Simulation Methods. Molecules 2019; 24:molecules24040753. [PMID: 30791496 PMCID: PMC6413221 DOI: 10.3390/molecules24040753] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/14/2019] [Accepted: 02/16/2019] [Indexed: 01/27/2023] Open
Abstract
The formation of transformation products (TPs) from contaminants and residues is becoming an increasing focus of scientific community. All organic compounds can form different TPs, thus demonstrating the complexity and interdisciplinarity of this topic. The properties of TPs could stand in relation to the unchanged substance or be more harmful and persistent. To get important information about the generated TPs, methods are needed to simulate natural and manmade transformation processes. Current tools are based on metabolism studies, photochemical methods, electrochemical methods, and Fenton’s reagent. Finally, most transformation processes are based on redox reactions. This review aims to compare these methods for structurally different compounds. The groups of pesticides, pharmaceuticals, brominated flame retardants, and mycotoxins were selected as important residues/contaminants relating to their worldwide occurrence and impact to health, food, and environmental safety issues. Thus, there is an increasing need for investigation of transformation processes and identification of TPs by fast and reliable methods.
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Koch C, Sures B. Environmental concentrations and toxicology of 2,4,6-tribromophenol (TBP). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 233:706-713. [PMID: 29126092 DOI: 10.1016/j.envpol.2017.10.127] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/29/2017] [Accepted: 10/29/2017] [Indexed: 06/07/2023]
Abstract
2,4,6-Tribromophenol is the most widely produced brominated phenol. In the present review, we summarize studies dealing with this substance from an environmental point of view. We cover concentrations in the abiotic and biotic environment including humans, toxicokinetics as well as toxicodynamics, and show gaps of the current knowledge about this chemical. 2,4,6-Tribomophenol occurs as an intermediate during the synthesis of brominated flame retardants and it similarly represents a degradation product of these substances. Moreover, it is used as a pesticide but also occurs as a natural product of some aquatic organisms. Due to its many sources, 2,4,6-tribromophenol is ubiquitously found in the environment. Nevertheless, not much is known about its toxicokinetics and toxicodynamics. It is also unclear which role the structural isomer 2,4,5-tribromophenol and several degradation products such as 2,4-dibromophenol play in the environment. Due to new flame retardants that enter the market and can degrade to 2,4,6-tribromophenol, this compound will remain relevant in future years - not only in aquatic matrices, but also in house dust and foodstuff, which are an important exposure route for humans.
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Affiliation(s)
- Christoph Koch
- Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University Duisburg-Essen, 45141 Essen, Germany; Deutsche Rockwool GmbH & Co. KG, 45966 Gladbeck, Germany.
| | - Bernd Sures
- Aquatic Ecology and Centre for Water and Environmental Research (ZWU), University Duisburg-Essen, 45141 Essen, Germany
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Krieger LK, Szeitz A, Bandiera SM. Hepatic microsomal metabolism of BDE-47 and BDE-99 by lesser snow geese and Japanese quail. CHEMOSPHERE 2017; 182:559-566. [PMID: 28525869 DOI: 10.1016/j.chemosphere.2017.05.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
In the present study, we investigated the oxidative biotransformation of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) by liver microsomes from wild lesser snow geese (Chen caerulescens caerulescens) and domesticated Japanese quail (Coturnix japonica). Formation of hydroxy-metabolites was analyzed using an ultra-high performance liquid chromatography-tandem mass spectrometry-based method. Incubation of BDE-47 with avian liver microsomes produced sixteen hydroxy-metabolites, eight of which were identified using authentic standards. The major metabolites formed by liver microsomes from individual lesser snow geese were 4-hydroxy-2,2',3,4'-tetrabromodiphenyl ether (4-OH-BDE-42), 3-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (3-OH-BDE-47), and 4'-hydroxy-2,2',4,5'-tetrabromodiphenyl ether (4'-OH-BDE-49). By comparison, 4-OH-BDE-42 and 4'-OH-BDE-49, but not 3-OH-BDE-47, were major metabolites of Japanese quail liver microsomes. Unidentified metabolites included monohydroxy- and dihydroxy-tetrabromodiphenyl ethers. Incubation of BDE-99 with avian liver microsomes produced seventeen hydroxy-metabolites, twelve of which were identified using authentic standards. The major metabolites formed by lesser snow goose liver microsomes were 2,4,5-tribromophenol, 3-OH-BDE-47, 4'-OH-BDE-49, 4-hydroxy-2,2',3,4',5-pentabromodiphenyl ether (4-OH-BDE-90), and 5'-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (5'-OH-BDE-99). By comparison, the major metabolites produced by liver microsomes from Japanese quail included 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47) and 2-hydroxy-2',3,4,4',5-pentabromodiphenyl ether (2-OH-BDE-123), but not 3-OH-BDE-47. Unidentified metabolites consisted of monohydroxy-pentabromodiphenyl ethers, monohydroxy-tetrabromodiphenyl ethers and dihydroxy-tetrabromodiphenyl ethers. Another difference between the two species was that formation rates of BDE-47 and BDE-99 metabolites were greater with liver microsomes from male than female Japanese quail, but a sex difference was not observed with lesser snow geese.
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Affiliation(s)
- Lisa K Krieger
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - András Szeitz
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Stelvio M Bandiera
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada.
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Huang H, Wang D, Wan W, Wen B. Hexabromocyclododecanes in soils and plants from a plastic waste treatment area in North China: occurrence, diastereomer- and enantiomer-specific profiles, and metabolization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:21625-21635. [PMID: 28752306 DOI: 10.1007/s11356-017-9792-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/19/2017] [Indexed: 06/07/2023]
Abstract
Plastic waste is a source of organic contaminants such as hexabromocyclododecanes (HBCDs). HBCDs have been found to cause developmental and reproductive toxicity; it is important to investigate the occurrence and metabolization of HBCDs in the soil environments with plastic waste contamination. This work analyzed HBCDs and their metabolites in soil and plant samples collected from Xinle and Dingzhou-the major plastic waste recycling centers in North China. Results showed that total HBCD concentrations in soils followed the order: plastic waste treatment site (11.0-624 ng/g) > roadside (2.96-85.4 ng/g) ≥ farmland (8.69-55.5 ng/g). HBCDs were detected in all the plant samples with total concentrations ranging from 3.47 to 23.4 ng/g. γ-HBCD was the dominant congener in soils, while α-HBCD was preferentially accumulated in plants. Compositions of HBCD isomers in soils and plants were significantly different (P < 0.05) among sampling sites and among plant species. HBCDs in farmland soil and all plant samples exhibited high enantio-selectivity based on the enantiomeric fractions (EFs). Furthermore, metabolites of pentabromocyclododecenes (PBCDEs) were frequently identified in soils, and mono-OH-HBCDs were the most common ones in plants. This study for the first time provides evidences of HBCD contamination in the soil-plant system caused by plastic waste, their stereo-selectivity, and metabolization behavior, improving our understanding of the environmental behavior and fate of HBCDs.
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Affiliation(s)
- Honglin Huang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing, 100085, China.
| | - Dan Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing, 100085, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Weining Wan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing, 100085, China
| | - Bei Wen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing, 100085, China
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Zheng X, Qiao L, Sun R, Luo X, Zheng J, Xie Q, Sun Y, Mai B. Alteration of Diastereoisomeric and Enantiomeric Profiles of Hexabromocyclododecanes (HBCDs) in Adult Chicken Tissues, Eggs, and Hatchling Chickens. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:5492-5499. [PMID: 28440626 DOI: 10.1021/acs.est.6b06557] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The concentrations and enantiomer fractions (EFs) of α-, β-, and γ-hexabromocyclododecanes (HBCDs) were measured in chicken diet sources (soil and chicken feed), home-raised adult chicken (Gallus domesticus) tissues, eggs during incubation, and hatchling chicken tissues. HBCD concentrations were not detected-0.69 ng/g dry weight (dw) and 25.6-48.4 ng/g dw in chicken feed and soil, respectively. HBCDs were detected in all adult chicken tissues, except the brain, at median levels of 13.1-44.0 ng/g lipid weight (lw). The proportions of α-HBCD in total HBCDs increased from 51% in soil to more than 87% in adult chicken tissues. The accumulation ratios (ARs) of α-HBCD from diet to adult chicken tissues were 4.27 for liver, 11.2 for fat, and 7.64-12.9 for other tissues, respectively. The AR and carry-over rate (COR) of α-HBCD from diet to eggs were 22.4 and 0.226, respectively. The concentrations of α-HBCD in hatchling chicken liver (median: 35.4 ng/g lw) were significantly lower than those in hatchling chicken pectoral muscle (median: 130 ng/g lw). The EFs of α-HBCD decreased from soil to adult chicken tissues and from eggs to hatchling chicken liver. Meanwhile, the EFs of γ-HBCD increased from soil to adult chicken tissues. These results indicate the preferential enrichment of (-)-α-HBCD and (+)-γ-HBCD in chickens. The alteration of diastereoisomeric and enantiomeric patterns of HBCDs might be influenced by the different absorption and elimination rates of the six HBCD enantiomers as well as variations in HBCD metabolism in chickens.
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Affiliation(s)
- Xiaobo Zheng
- College of Resources and Environment, South China Agricultural University , Guangzhou 510642, People's Republic of China
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, People's Republic of China
| | - Lin Qiao
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, People's Republic of China
| | - Runxia Sun
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, People's Republic of China
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, People's Republic of China
| | - Jing Zheng
- Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection , Guangzhou 510655, People's Republic of China
| | - Qilai Xie
- College of Resources and Environment, South China Agricultural University , Guangzhou 510642, People's Republic of China
| | - Yuxin Sun
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences , Guangzhou 510301, People's Republic of China
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, People's Republic of China
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Li ZR, Luo XJ, Huang LQ, Mai BX. In ovo uptake, metabolism, and tissue-specific distribution of chiral PCBs and PBDEs in developing chicken embryos. Sci Rep 2016; 6:36597. [PMID: 27819361 PMCID: PMC5098194 DOI: 10.1038/srep36597] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/29/2016] [Indexed: 11/28/2022] Open
Abstract
Fertilized chicken eggs were injected with environmental doses of 4 chiral polychlorinated biphenyls (PCBs) and 8 polybrominated biphenyl ethers (PBDEs) to investigate their uptake, metabolism in the embryo, and distribution in the neonate chicken. PCB95 uptake was the most efficient (80%) whereas BDE209 was the least (56%). Embryos metabolized approximately 52% of the PCBs absorbed. Though some degree of metabolism in the first 18 days, most of the PCBs and PBDEs was metabolized in the last three days, when BDE85, 99, 153, and 209 decrease by 11–37%. Enantioselective metabolism of the (+) enantiomers of PCB95, 149, and 132 and the (−) enantiomer of PCB91 was observed. The enantioselective reactivity was higher with the two penta-PCBs than the two tetra-PCBs. Liver, exhibited high affinity for high lipophilic chemicals, enrich all chemicals that was deflected in other tissues except for some special chemicals in a given tissues. Lipid composition, time of organ formation, and metabolism contribute to the distribution of chemicals in the neonate chicken. The result of this study will improve our understanding on the fate and potential adverse effects of PCBs and PBDEs in the neonate chicken.
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Affiliation(s)
- Zong-Rui Li
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Jun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Li-Qian Huang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bi-Xian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
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Huang X, Chen C, Shang Y, Zhong Y, Ren G, Yu Z, An J. In vitro study on the biotransformation and cytotoxicity of three hexabromocyclododecane diastereoisomers in liver cells. CHEMOSPHERE 2016; 161:251-258. [PMID: 27434255 DOI: 10.1016/j.chemosphere.2016.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/27/2016] [Accepted: 07/01/2016] [Indexed: 06/06/2023]
Abstract
In order to clarify the cytotoxicity of hexabromocyclododecane (HBCD) diastereoisomers, and to investigate the correlation of cytotoxicity and biotransformation of HBCDs, the immortalized human liver cells L02 and human hepatoma cells HepG2 were exposed to individual HBCD diastereoisomer (α-, β- and γ-HBCD). Cytotoxicity was assayed in terms of cell viability, reactive oxygen species (ROS) level and DNA damage. Metabolic rate, bioisomerization and enantiomer fractions were analyzed using the liquid chromatograph coupled to triple quadrupole mass spectrometer (LC-MS/MS). The α-, β- and γ-HBCD all had cytotoxicity in L02 and HepG2 cells with the toxicity order β-HBCD ≥ γ-HBCD > α-HBCD according to the results of proliferation assay. The cytotoxicity mechanism between the two cells seemed different: a) the stability of intracellular redox state plays an important role in inducing cell toxicity in HepG2 cells. b) DNA damage status is central to inhibit proliferation in L02 cells. The metabolic capability of HepG2 was superior to L02 for HBCD diastereoisomers, which may explain the greater toxicity of HBCDs in HepG2 cells. The bioisomerization and enantiomer enrichment were also detected in this study, although the results were inconsistent with other reports, which might result from species-specific differences in HBCDs metabolism or experimental conditions. The cytotoxicity and metabolic mechanism of individual enantiomers must be further investigated to evaluate the health risks of HBCDs.
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Affiliation(s)
- Xiaomei Huang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China; University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Cen Chen
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Yu Shang
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Yufang Zhong
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Guofa Ren
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China
| | - Jing An
- Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, PR China.
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23
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Erratico C, Zheng X, van den Eede N, Tomy G, Covaci A. Stereoselective Metabolism of α-, β-, and γ-Hexabromocyclododecanes (HBCDs) by Human Liver Microsomes and CYP3A4. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8263-8273. [PMID: 27401979 DOI: 10.1021/acs.est.6b01059] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This is the first study investigating the in vitro metabolism of α-, β-, and γ-hexabromocyclododecane (HBCD) stereoisomers in humans and providing semiquantitative metabolism data. Human liver microsomes were incubated with individual racemic mixtures and with individual stereoisomers of α-, β-, and γ-HBCDs, the hydroxylated metabolites formed were analyzed by liquid chromatography-tandem mass spectrometry, and the value of the intrinsic in vitro clearance (Clint,vitro) was calculated. Several mono- and dihydroxylated metabolites of α-, β-, and γ-HBCDs were formed, with mono-OH-HBCDs being the major metabolites. No stereoisomerization of any of the six α-, β-, and γ-HBCD isomers catalyzed by cytochrome P450 (CYP) enzymes occurred. The value of Clint,vitro of α-HBCDs was significantly lower than that of β-HBCDs, which, in turn, was significantly lower than that of γ-HBCDs (p < 0.05). Such differences were explained by the significantly lower values of Clint,vitro of each α-HBCD stereoisomer than those of the β- and γ-HBCD stereoisomers. In addition, significantly lower values of Clint,vitro of the (-) over the (+)α- and β-HBCD stereoisomers, but not γ-HBCDs, were obtained. Our data offer a possible explanation of the enrichment of α-HBCDs over β- and γ-HBCDs on the one hand and, on the other hand, of (-)α-HBCDs over (+)α-HBCDs previously reported in human samples. It also offers information about the mechanism resulting in such enrichments, the stereoisomer-selective metabolism of α-, β-, and γ-HBCDs catalyzed by CYPs with the lack of stereoisomerization.
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Affiliation(s)
- Claudio Erratico
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Xiaobo Zheng
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
- Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China
| | - Nele van den Eede
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Gregg Tomy
- Department of Chemistry, University of Manitoba , Winnipeg R3T 2N2, Canada
| | - Adrian Covaci
- Toxicological Center, University of Antwerp , Universiteitsplein 1, 2610 Wilrijk, Belgium
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Zheng X, Erratico C, Luo X, Mai B, Covaci A. Oxidative metabolism of BDE-47, BDE-99, and HBCDs by cat liver microsomes: Implications of cats as sentinel species to monitor human exposure to environmental pollutants. CHEMOSPHERE 2016; 151:30-36. [PMID: 26923239 DOI: 10.1016/j.chemosphere.2016.02.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 06/05/2023]
Abstract
The in vitro oxidative metabolism of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), and individual α-, β- and γ-hexabromocyclododecane (HBCD) isomers catalyzed by cytochrome P450 (CYP) enzymes was screened using cat liver microsomes (CLMs). Six hydroxylated metabolites, namely 4-hydroxy-2,2',3,4'-tetrabromodiphenyl ether (4-OH-BDE-42), 3-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (3-OH-BDE-47), 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE-47), 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE-47), 4'-hydroxy-2,2',4,5'- tetrabromodiphenyl ether (4'-OH-BDE-49), and 2'-hydroxy-2,3',4,4'-tetrabromodiphenyl ether (2'-OH-BDE-66), were identified and quantified after incubation of BDE-47. A di-OH-tetra-BDE was also found as metabolite of BDE-47 with CLMs. 5-OH-BDE-47 was the major metabolite formed. Five hydroxylated metabolites (3'-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (3'-OH-BDE-99), 5'-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (5'-OH-BDE-99), 6-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (6-OH-BDE-99), 6'-hydroxy-2,2',4,4',5-pentabromodiphenyl ether (6'-OH-BDE-99), and 4'-hydroxy-2,2',4,5,5'-pentabromodiphenyl ether (4'-OH-BDE-101) were formed from BDE-99 incubated with CLMs. Concentrations of BDE-99 metabolites were lower than those of BDE-47. Four or more mono-hydroxylated HBCD (OH-HBCDs), four or more di-hydroxylated HBCD (di-OH-HBCDs), five or more mono-hydroxylated pentabromocyclododecanes (OH-PBCDs), and five or more di-hydroxylated pentabromocyclododecenes (di-OH-PBCDs) were detected after incubation of α-, β-, or γ-HBCD with CLMs. No diastereoisomeric or enantiomeric enzymatic isomerisation was observed incubating α-, β- or γ-HBCD with CLMs. Collectively, our data suggest that (i) BDE-47 is metabolized at a faster rate than BDE-99 by CLMs, (ii) OH-HBCDs are the major hydroxylated metabolites of α-, β- and γ-HBCD produced by CLMs, and (iii) the oxidative metabolism of BDE-47 and BDE-99 is different by cat and human liver microsomes. This suggests that cats are not a suitable sentinel to represent internal exposure of PBDEs for humans, but is likely a promising sentinel for internal HBCDs exposure for humans.
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Affiliation(s)
- Xiaobo Zheng
- Key Laboratory of Soil Environment and Waste Reuse in Agriculture of Guangdong Higher Education Institutions, College of Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Claudio Erratico
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
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