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Sanz-Sáez I, Bravo AG, Ferri M, Carreras JM, Sánchez O, Sebastian M, Ruiz-González C, Capo E, Duarte CM, Gasol JM, Sánchez P, Acinas SG. Microorganisms Involved in Methylmercury Demethylation and Mercury Reduction are Widely Distributed and Active in the Bathypelagic Deep Ocean Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39046290 DOI: 10.1021/acs.est.4c00663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
The ocean's mercury (Hg) content has tripled due to anthropogenic activities, and although the dark ocean (>200 m) has become an important Hg reservoir, concentrations of the toxic and bioaccumulative methylmercury (MeHg) are low and therefore very difficult to measure. As a consequence, the current understanding of the Hg cycle in the deep ocean is severely data-limited, and the factors controlling MeHg, as well as its transformation rates, remain largely unknown. By analyzing 52 globally distributed bathypelagic deep-ocean metagenomes and 26 new metatranscriptomes from the Malaspina Expedition, our study reveals the widespread distribution and expression of bacterial-coding genes merA and merB in the global bathypelagic ocean (∼4000 m depth). These genes, associated with HgII reduction and MeHg demethylation, respectively, are particularly prevalent within the particle-attached fraction. Moreover, our results indicate that water mass age and the organic matter composition shaped the structure of the communities harboring merA and merB genes living in different particle size fractions, their abundance, and their expression levels. Members of the orders Corynebacteriales, Rhodobacterales, Alteromonadales, Oceanospirillales, Moraxellales, and Flavobacteriales were the main taxonomic players containing merA and merB genes in the deep ocean. These findings, together with our previous results of pure culture isolates of the deep bathypelagic ocean possessing the metabolic capacity to degrade MeHg, indicated that both methylmercury demethylation and HgII reduction likely occur in the global dark ocean, the largest biome in the biosphere.
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Affiliation(s)
- Isabel Sanz-Sáez
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Andrea G Bravo
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Marta Ferri
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Joan-Martí Carreras
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Olga Sánchez
- Departament de Genètica i Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Spain
| | - Marta Sebastian
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Clara Ruiz-González
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Eric Capo
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Carlos M Duarte
- Red Sea Research Center, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900,Saudi Arabia
| | - Josep M Gasol
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Pablo Sánchez
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Silvia G Acinas
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, ICM-CSIC, 08003 Barcelona, Catalunya, Spain
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2
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Wang Z, Zhang A, Hua T, Chen X, Zhu M, Guo Z, Song Y, Yang G, Li S, Feng J, Li M, Yan W. Revealing the interaction forms between Hg(II) and group types (-Cl, -CN, -NH 2, -OH, -COOH) in functionalized Poly(pyrrole methane)s for efficient mercury removal. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 351:124049. [PMID: 38692386 DOI: 10.1016/j.envpol.2024.124049] [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: 03/14/2024] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
To explore the impact of different functional groups on Hg(II) adsorption, a range of poly(pyrrole methane)s functionalized by -Cl, -CN, -NH2, -OH and -COOH were synthesized and applied to reveal the interaction between different functional groups and mercury ions in water, and the adsorption mechanism was revealed through combined FT-IR, XPS, and DFT calculations. The adsorption performance can be improved to varying degrees by the incorporation of functional groups. Among them, the oxygen-containing functional groups (-OH and -COOH) exhibit stronger affinity for Hg(II) and can increase the adsorption capacity from 180 mg g-1 to more than 1400 mg g-1 at 318 K, with distribution coefficient (Kd) exceeding 105 mL g-1. The variations in the capture and immobilization capabilities of functionalized poly(pyrrole methane)s predominantly stem from the unique interactions between their functional groups and mercury ions. In particular, oxygen-containing -OH and -COOH effectively capture Hg(OH)2 through hydrogen bonding, and further deprotonate to form the -O-Hg-OH and -COO-Hg-OH complexes which are more stable than those obtained from other functionalized groups. Finally, the ecological safety has been fully demonstrated through bactericidal and bacteriostatic experiments to prove the functionalized poly(pyrrole methane)s can be as an environmentally friendly adsorbent for purifying contaminated water.
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Affiliation(s)
- Zhenyu Wang
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Aijing Zhang
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Tingyu Hua
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xin Chen
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Mengyuan Zhu
- International Research Center for Renewable Energy (IRCRE), State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Ziyu Guo
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yanna Song
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Guorui Yang
- School of Chemistry, Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, "Four Joint Subjects One Union" School-Enterprise Joint Research Center for Power Battery Recycling & Circulation Utilization Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Shanshan Li
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jiangtao Feng
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China; International Research Center for Renewable Energy (IRCRE), State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
| | - Mingtao Li
- International Research Center for Renewable Energy (IRCRE), State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Wei Yan
- Department of Environmental Engineering, Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
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3
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Chaudhary DK, Seo D, Han S, Hong Y. Distribution of mercury in modern bottom sediments of the Beaufort Sea in relation to the processes of early diagenesis: Microbiological aspect. MARINE POLLUTION BULLETIN 2024; 202:116300. [PMID: 38555803 DOI: 10.1016/j.marpolbul.2024.116300] [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: 10/30/2023] [Revised: 02/23/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
This study investigated the contents of total mercury (THg), trace metals, and CH4 and determined the signature microbes involved in various biogeochemical processes in the sediment of the Canadian Beaufort Sea. The THg ranged between 32 and 63 μg/kg and the trace metals such as Fe, Al, Mn, and Zn were significant in distributions. The pH, SO42-, Fe2+, and redox proxy metals were crucial factors in the spatial and vertical heterogeneity of geochemical distributions. CH4 was detected only at the mud volcano site. Microbial analyses identified Clostridium, Desulfosporosinus, Desulfofustis, and Desulftiglans as the predominant Hg methylators and sulfate reducers; Nitrosopumilus and Hyphomicrobium as the major nitrifiers and denitrifiers; Methanosarcina and Methanosaeta as keystone methanogens; and Methyloceanibacter and Methyloprofundus as signature methanotrophs. Altogether, this study expands the current understanding of the microbiological and geochemical features and could be helpful in predicting ecosystem functions in the Canadian Beaufort Sea.
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Affiliation(s)
- Dhiraj Kumar Chaudhary
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City 30019, Republic of Korea
| | - DongGyun Seo
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City 30019, Republic of Korea
| | - Seunghee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Gwangju 61005, Republic of Korea
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City 30019, Republic of Korea.
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Hao X, Zhao Q, Zhou X, Huang Q, Liu YR. Labile carbon inputs boost microbial contribution to legacy mercury reduction and emissions from industry-polluted soils. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133122. [PMID: 38056276 DOI: 10.1016/j.jhazmat.2023.133122] [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: 08/28/2023] [Revised: 10/24/2023] [Accepted: 11/27/2023] [Indexed: 12/08/2023]
Abstract
Soils is a crucial reservoir influencing mercury (Hg) emissions and soil-air exchange dynamics, partially modulated by microbial reducers aiding Hg reduction. Yet, the extent to which microbial engagements contribute to soil Hg volatilization remains largely unknown. Here, we characterized Hg-reducing bacterial communities in natural and anthropogenically perturbed soil environments and quantified their contribution to soil Hg(0) volatilization. Our results revealed distinct Hg-reducing bacterial compositions alongside elevated mercuric reductase (merA) gene abundance and diversity in soils adjacent to chemical factories compared to less-impacted ecosystems. Notably, solely industry-impacted soils exhibited increased merA gene abundance along Hg gradients, indicating microbial adaption to Hg selective pressure through quantitative changes in Hg reductase and genetic diversity. Microcosm studies demonstrated that glucose inputs boosted microbial involvement and induced 2-8 fold increments in cumulative Hg(0) volatilization in industry-impacted soils. Microbially-mediated Hg reduction contributed to 41.6% of soil Hg(0) volatilization in industry-impacted soils under 25% water-holding capacity and glucose input conditions over a 21-day incubation period. Alcaligenaceae, Moraxellaceae, Nitrosomonadaceae and Shewanellaceae were identified as potential contributors to Hg(0) volatilization in the soil. Collectively, our study provides novel insights into microbially-mediated Hg reduction and soil-air exchange processes, with important implications for risk assessment and management of industrial Hg-contaminated soils.
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Affiliation(s)
- Xiuli Hao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Qianqian Zhao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Xinquan Zhou
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu-Rong Liu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China.
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5
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Rincón-Tomás B, Lanzén A, Sánchez P, Estupiñán M, Sanz-Sáez I, Bilbao ME, Rojo D, Mendibil I, Pérez-Cruz C, Ferri M, Capo E, Abad-Recio IL, Amouroux D, Bertilsson S, Sánchez O, Acinas SG, Alonso-Sáez L. Revisiting the mercury cycle in marine sediments: A potential multifaceted role for Desulfobacterota. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133120. [PMID: 38101011 DOI: 10.1016/j.jhazmat.2023.133120] [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: 08/31/2023] [Revised: 10/10/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023]
Abstract
Marine sediments impacted by urban and industrial pollutants are typically exposed to reducing conditions and represent major reservoirs of toxic mercury species. Mercury methylation mediated by anaerobic microorganisms is favored under such conditions, yet little is known about potential microbial mechanisms for mercury detoxification. We used culture-independent (metagenomics, metabarcoding) and culture-dependent approaches in anoxic marine sediments to identify microbial indicators of mercury pollution and analyze the distribution of genes involved in mercury reduction (merA) and demethylation (merB). While none of the isolates featured merB genes, 52 isolates, predominantly affiliated with Gammaproteobacteria, were merA positive. In contrast, merA genes detected in metagenomes were assigned to different phyla, including Desulfobacterota, Actinomycetota, Gemmatimonadota, Nitrospirota, and Pseudomonadota. This indicates a widespread capacity for mercury reduction in anoxic sediment microbiomes. Notably, merA genes were predominately identified in Desulfobacterota, a phylum previously associated only with mercury methylation. Marker genes involved in the latter process (hgcAB) were also mainly assigned to Desulfobacterota, implying a potential central and multifaceted role of this phylum in the mercury cycle. Network analysis revealed that Desulfobacterota were associated with anaerobic fermenters, methanogens and sulfur-oxidizers, indicating potential interactions between key players of the carbon, sulfur and mercury cycling in anoxic marine sediments.
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Affiliation(s)
- Blanca Rincón-Tomás
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain; Grupo Inv. Geología Aplicada a Recursos Marinos y Ambientes Extremos, Instituto Geológico y Minero de España (IGME-CSIC), 28003 Madrid, Spain.
| | - Anders Lanzén
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Pablo Sánchez
- Dep. Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), 08003 Barcelona, Spain
| | - Mónica Estupiñán
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain
| | - Isabel Sanz-Sáez
- Dep. Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), 08003 Barcelona, Spain
| | - M Elisabete Bilbao
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain
| | - Diana Rojo
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain
| | - Iñaki Mendibil
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain
| | - Carla Pérez-Cruz
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain
| | - Marta Ferri
- Dep. Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), 08003 Barcelona, Spain
| | - Eric Capo
- Dep. Ecology and Environmental Science, Umeå University, 907 36 Umeå, Sweden
| | - Ion L Abad-Recio
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain
| | - David Amouroux
- Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les matériaux (IPREM), Pau, France
| | - Stefan Bertilsson
- Dep. Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
| | - Olga Sánchez
- Dep. Genètica i Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona (UAB), 08192 Bellaterra, Spain
| | - Silvia G Acinas
- Dep. Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), 08003 Barcelona, Spain
| | - Laura Alonso-Sáez
- AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Txatxarramendi ugartea z/g, 48395 Sukarrieta, Spain.
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6
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Kumar Chaudhary D, Bajagain R, Seo D, Hong Y, Han S. Depth-dependent microbial communities potentially mediating mercury methylation and various geochemical processes in anthropogenically affected sediments. ENVIRONMENTAL RESEARCH 2023; 237:116888. [PMID: 37586452 DOI: 10.1016/j.envres.2023.116888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
Metal contamination and other geochemical alterations affect microbial composition and functional activities, disturbing natural biogeochemical cycles. Therefore, it is essential to understand the influences of multi-metal and geochemical interactions on microbial communities. This work investigated the distributions of total mercury (THg), methylmercury (MeHg), and trace metals in the anthropogenically affected sediment. The microbial communities and functional genes profiles were further determined to explore their association with Hg-methylation and geochemical features. The levels of THg and MeHg in sediment cores ranged between 10 and 40 mg/kg and 0.01-0.16 mg/kg, respectively, with an increasing trend toward bottom horizons. The major metals present at all depths were Al, Fe, Mn, and Zn. The enrichment and contamination indices confirmed that the trace metals were highly enriched in the anthropogenically affected sediment. Various functional genes were detected in all strata, indicating the presence of active microbial metabolic processes. The microbial community profiles revealed that the phyla Proteobacteria, Bacteroidetes, Bathyarchaeota, and Euryarchaeota, and the genera Thauera, Woeseia, Methanomethylovorans, and Methanosarcina were the dominant microbes. Correlating major taxa with geochemical variables inferred that sediment geochemistry substantially affects microbial community and biogeochemical cycles. Furthermore, archaeal methanogens and the bacterial phyla Chloroflexi and Firmicutes may play crucial roles in enhancing MeHg levels. Overall, these findings shed new light on the microbial communities potentially involved in Hg-methylation process and other biogeochemical cycles.
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Affiliation(s)
- Dhiraj Kumar Chaudhary
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea
| | - Rishikesh Bajagain
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea
| | - DongGyun Seo
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, Republic of Korea.
| | - Seunghee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Republic of Korea
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7
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Li S, Yang L, Wu J, Yao L, Han D, Liang Y, Yin Y, Hu L, Shi J, Jiang G. Efficient and selective removal of Hg(II) from water using recyclable hierarchical MoS 2/Fe 3O 4 nanocomposites. WATER RESEARCH 2023; 235:119896. [PMID: 36965293 DOI: 10.1016/j.watres.2023.119896] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/07/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
Developing practical and cost-effective adsorbents with satisfactory mercury (Hg) remediation capability is indispensable for aquatic environment safety and public health. Herein, a recyclable hierarchical MoS2/Fe3O4 nanocomposite (by in-situ growth of MoS2 nanosheets on the surface of Fe3O4 nanospheres) is presented for the selective removal of Hg(II) from aquatic samples. It exhibited high adsorption capacity (∼1923.5 mg g -1), fast kinetics (k2 ∼ 0.56 mg g -1 min-1), broad working pH range (2-11), excellent selectivity (Kd > 1.0 × 107 mL g -1), and great reusability (removal efficiency > 90% after 20 cycles). In particular, removal efficiencies of up to ∼97% for different Hg(II) concentrations (10-1000 μg L -1) in natural water and industrial effluents confirmed the practicability of MoS2/Fe3O4. The possible mechanism for effective Hg(II) removal was discussed by a series of characterization analyses, which was attributed to the alteration of the MoS2 structure and the surface coordination of Hg-S. The accessibility of surface sulfur sites and the diffusion of Hg(II) in the solid-liquid system were enhanced due to the advantage of the expanded interlayer spacing (0.96 nm) and the hierarchical structure. This study suggests that MoS2/Fe3O4 is a promising material for Hg(II) removal in actual scenarios and provides a feasible approach by rationally constructing hierarchical structures to promote the practical applications of MoS2 in sustainable water treatments.
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Affiliation(s)
- Shiyu Li
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310000, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lin Yang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jialong Wu
- State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China
| | - Linlin Yao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Deming Han
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310000, China
| | - Yong Liang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yongguang Yin
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310000, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ligang Hu
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310000, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jianbo Shi
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310000, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China.
| | - Guibin Jiang
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310000, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Huang Q, Liu Z, Guo Y, Li B, Yang Z, Liu X, Ni J, Li X, Zhang X, Zhou N, Yin H, Jiang C, Hao L. Coal-source acid mine drainage reduced the soil multidrug-dominated antibiotic resistome but increased the heavy metal(loid) resistome and energy production-related metabolism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162330. [PMID: 36813198 DOI: 10.1016/j.scitotenv.2023.162330] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 02/07/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
A recent global scale study found that mining-impacted environments have multi-antibiotic resistance gene (ARG)-dominated resistomes with an abundance similar to urban sewage but much higher than freshwater sediment. These findings raised concern that mining may increase the risk of ARG environmental proliferation. The current study assessed how typical multimetal(loid)-enriched coal-source acid mine drainage (AMD) contamination affects soil resistomes by comparing with background soils unaffected by AMD. Both contaminated and background soils have multidrug-dominated antibiotic resistomes attributed to the acidic environment. AMD-contaminated soils had a lower relative abundance of ARGs (47.45 ± 23.34 ×/Gb) than background soils (85.47 ± 19.71 ×/Gb) but held high-level heavy metal(loid) resistance genes (MRGs, 133.29 ± 29.36 ×/Gb) and transposase- and insertion sequence-dominated mobile genetic elements (MGEs, 188.51 ± 21.81 ×/Gb), which was 56.26 % and 412.12 % higher than background soils, respectively. Procrustes analysis showed that the microbial community and MGEs exerted more influence on driving heavy metal(loid) resistome variation than antibiotic resistome. The microbial community increased energy production-related metabolism to fulfill the increasing energy needs required by acid and heavy metal(loid) resistance. Horizontal gene transfer (HGT) events primarily exchanged energy- and information-related genes to adapt to the harsh AMD environment. These findings provide new insight into the risk of ARG proliferation in mining environments.
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Affiliation(s)
- Qiang Huang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Zhenghua Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, PR China
| | - Yuan Guo
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Bao Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Zhenni Yang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Xiaoling Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Jianmei Ni
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China
| | - Xiutong Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xi Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Nan Zhou
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, PR China
| | - Chengying Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Likai Hao
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, PR China.
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Abstract
The desiccation of the Aral Sea represents one of the largest human-made environmental regional disasters. The salt- and toxin-enriched dried-out basin provides a natural laboratory for studying ecosystem functioning and rhizosphere assembly under extreme anthropogenic conditions. Here, we investigated the prokaryotic rhizosphere communities of the native pioneer plant Suaeda acuminata (C.A.Mey.) Moq. in comparison to bulk soil across a gradient of desiccation (5, 10, and 40 years) by metagenome and amplicon sequencing combined with quantitative PCR (qPCR) analyses. The rhizosphere effect was evident due to significantly higher bacterial abundances but less diversity in the rhizosphere compared to bulk soil. Interestingly, in the highest salinity (5 years of desiccation), rhizosphere functions were mainly provided by archaeal communities. Along the desiccation gradient, we observed a significant change in the rhizosphere microbiota, which was reflected by (i) a decreasing archaeon-bacterium ratio, (ii) replacement of halophilic archaea by specific plant-associated bacteria, i.e., Alphaproteobacteria and Actinobacteria, and (iii) an adaptation of specific, potentially plant-beneficial biosynthetic pathways. In general, both bacteria and archaea were found to be involved in carbon cycling and fixation, as well as methane and nitrogen metabolism. Analysis of metagenome-assembled genomes (MAGs) showed specific signatures for production of osmoprotectants, assimilatory nitrate reduction, and transport system induction. Our results provide evidence that rhizosphere assembly by cofiltering specific taxa with distinct traits is a mechanism which allows plants to thrive under extreme conditions. Overall, our findings highlight a function-based rhizosphere assembly, the importance of plant-microbe interactions in salinated soils, and their exploitation potential for ecosystem restoration approaches. IMPORTANCE The desertification of the Aral Sea basin in Uzbekistan and Kazakhstan represents one of the most serious anthropogenic environmental disasters of the last century. Since the 1960s, the world's fourth-largest inland body of water has been constantly shrinking, which has resulted in an extreme increase of salinity accompanied by accumulation of many hazardous and carcinogenic substances, as well as heavy metals, in the dried-out basin. Here, we investigated bacterial and archaeal communities in the rhizosphere of pioneer plants by combining classic molecular methods with amplicon sequencing as well as metagenomics for functional insights. By implementing a desiccation gradient, we observed (i) remarkable differences in the archaeon-bacterium ratio of plant rhizosphere samples, (ii) replacement of archaeal indicator taxa during succession, and (iii) the presence of specific, potentially plant-beneficial biosynthetic pathways in archaea present during the early stages. In addition, our results provide hitherto-undescribed insights into the functional redundancy between plant-associated archaea and bacteria.
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10
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Cardona GI, Escobar MC, Acosta-González A, Marín P, Marqués S. Highly mercury-resistant strains from different Colombian Amazon ecosystems affected by artisanal gold mining activities. Appl Microbiol Biotechnol 2022; 106:2775-2793. [PMID: 35344092 PMCID: PMC8990959 DOI: 10.1007/s00253-022-11860-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 01/28/2022] [Accepted: 02/27/2022] [Indexed: 02/07/2023]
Abstract
Two sites of the Colombian Amazon region with different levels of human intervention and mercury pollution were selected for the collection of samples of river and lake water, sediments, and associated forest soils. The Tarapacá region, affected mainly by barrage mining, showed low mercury concentrations, whilst in the Taraira region, affected by underground mining, there were several points with high mercury pollution levels. A collection of 72 bacterial and 10 yeast strains with different levels of mercury resistance was isolated and characterized. Most of the highly resistant bacterial strains (MIC > 40 mg L−1 HgCl2) were isolated from soil and sediment samples and belonged to either Pseudomonas (60%) or Bacillus (20%). Most of highly resistant bacterial strains were positive for the presence of the merA gene, suggesting an active mercury resistance mechanism. This was confirmed in the two most resistant strains, Pseudomonas sp. TP30 and Burkholderia contaminans TR100 (MIC = 64 and 71 mg L−1 HgCl2, respectively), which in the presence of increasing mercury concentrations expressed the merA gene at increasing levels, concomitant with a significant mercury reduction activity. Analysis of the MerA sequences present in the different isolates suggested a high gene conservation within the taxonomic groups but also several horizontal gene transfer events between taxonomically distant genera. We also observed a positive correspondence between the presence of the merA gene and the number of antibiotics to which the strains were resistant to. The most resistant strains are good candidates for future applications in the bioremediation of mercury-contaminated sites in the Amazon. Key points • Amazon sediments affected by underground gold mining have higher Hg levels. • Highly Hg-resistant isolates belonged to Pseudomonas and Bacillus genera. • TR100 and TP30 strains showed remediation potential to be used in the Amazon region.
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Affiliation(s)
- Gladys Inés Cardona
- Instituto Amazónico de Investigaciones Científicas SINCHI, 110321, Bogotá, Colombia.
| | - María Camila Escobar
- Instituto Amazónico de Investigaciones Científicas SINCHI, 110321, Bogotá, Colombia
| | | | - Patricia Marín
- Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Department of Environmental Protection, Granada, Spain
| | - Silvia Marqués
- Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, Department of Environmental Protection, Granada, Spain
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11
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Rani L, Srivastav AL, Kaushal J. Bioremediation: An effective approach of mercury removal from the aqueous solutions. CHEMOSPHERE 2021; 280:130654. [PMID: 34162069 DOI: 10.1016/j.chemosphere.2021.130654] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 04/03/2021] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
Mercury (Hg(II)) is the 16th rarest element present in the earth's crust. Due to rapid industrialization and urban expansions, the mercury concentration has been elevated in the environment. Hg(II) contamination in the aqueous environment has become a great challenge for human beings. The main source of Hg(II) in the aqueous phase is untreated effluent industries (such as the paper industry). Hg(II) is non-biodegradable in nature and even its trace amount in an aqueous environment can pose chronic threats among the humans (damage to the central nervous system, respiratory system, and cardiovascular system, mutation of DNA), animals, and aquatic creatures. Therefore, the removal of mercury from aqueous solutions is an urgent need of the modern era. The conventional techniques such as ion exchange, precipitation, membrane filtrations are costly and also generate byproducts in the environment. Bioremediation is a sustainable, environmentally sound, and cost-effective technique to remove Hg(II) from the aqueous solutions. In this process, naturally occurring microorganisms are utilized to remove the Hg(II) from the aqueous solutions. Lentinus edodes, U. lactuca, and Typha domingensis are found to have great potential to remove mercury from water ranged from ~100 mg g-1 to 337 mg g-1.
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Affiliation(s)
- Lata Rani
- Centre for Water Sciences, Chitkara University Institute of Engineering & Technology, Chitkara University, Punjab, 140 417, India; School of Basic Sciences, Chitkara University, Himachal Pradesh, 174 103, India
| | - Arun Lal Srivastav
- Chitkara University School of Engineering and Technology, Chitkara University, Himachal Pradesh, 174 103, India.
| | - Jyotsna Kaushal
- Centre for Water Sciences, Chitkara University Institute of Engineering & Technology, Chitkara University, Punjab, 140 417, India
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12
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Amin A, Naveed M, Munawar U, Sarwar A, Latif Z. Characterization of Mercury-Resistant Rhizobacteria for Plant Growth Promotion: An In Vitro and In Silico Approach. Curr Microbiol 2021; 78:3968-3979. [PMID: 34550433 DOI: 10.1007/s00284-021-02660-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
In this study, a total 30 rhizobacterial isolates were screened out based on resistance against different concentrations of mercuric chloride (HgCl2), growth on nitrogen-free mannitol (NFM) and production of indole-3-acetic acid (IAA). The biochemical and plant growth promoting characterization of selected isolates was performed by different biochemical tests. Out of 30, six isolates, UM-3, AZ-5, UM-7, UM-11, UM-26, and UM-28 showed resistance at 30 µg/ml HgCl2, pronounced growth on NFM and high production of IAA as 18.6, 16.7, 16, 18.7, 14, and 16 µg/ml, respectively (P < 0.05). The 16S rDNA ribotyping and phylogenetic analysis of selected bacterial isolates were performed and characterized as Exiguobacterium sp. UM-3 (KJ736011), Bacillus thuringiensis AZ-5 (KJ675627), Bacillus subtilis UM-7 (KJ736013), Enterobacter cloacae UM-11 (KJ736014), Pseudomonas aeruginosa UM-26 (KJ736016), P. aeruginosa UM-28 (KJ736017) and Bacillus pumilus UM-16 (KJ736015) used as negative control. B. thuringiensis AZ-5 showed high resistance against 30 µg/ml of HgCl2 due to the presence of merB gene. The structural determination of MerB protein was carried out using bioinformatics tools, i.e., Protparam, Pfam, InterProScan, STRING, Jpred4, PSIPRED, I-TASSER, COACH server and ERRAT. These tools predicted the structural based functional homology of MerB protein (organomercuric lyase) in association with MerA (mercuric reductase) in bacterial Hg-detoxification system.
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Affiliation(s)
- Aatif Amin
- Department of Microbiology, Faculty of Life Sciences, University of Central Punjab, Lahore, 54000, Pakistan.
| | - Muhammad Naveed
- Department of Biotechnology, Faculty of Life Sciences, University of Central Punjab, Lahore, 54000, Pakistan
| | - Umair Munawar
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore, 54590, Pakistan
| | - Arslan Sarwar
- Department of Microbiology, Faculty of Life Sciences, University of Central Punjab, Lahore, 54000, Pakistan
| | - Zakia Latif
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Lahore, 54590, Pakistan
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13
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Rebelo A, Mourão J, Freitas AR, Duarte B, Silveira E, Sanchez-Valenzuela A, Almeida A, Baquero F, Coque TM, Peixe L, Antunes P, Novais C. Diversity of metal and antibiotic resistance genes in Enterococcus spp. from the last century reflects multiple pollution and genetic exchange among phyla from overlapping ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 787:147548. [PMID: 34000557 DOI: 10.1016/j.scitotenv.2021.147548] [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: 04/19/2021] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
Arsenic (As), mercury (Hg), and copper (Cu) are among the major historical and contemporary metal pollutants linked to global anthropogenic activities. Enterococcus have been considered indicators of fecal pollution and antibiotic resistance for years, but its largely underexplored metallome precludes understanding their role as metal pollution bioindicators as well. Our goal was to determine the occurrence, diversity, and phenotypes associated with known acquired genes/operons conferring tolerance to As, Hg or Cu among Enterococcus and to identify their genetic context (381 field isolates from diverse epidemiological and genetic backgrounds; 3547 enterococcal genomes available in databases representing a time span during 1900-2019). Genes conferring tolerance to As (arsA), Hg (merA) or Cu (tcrB) were used as biomarkers of widespread metal tolerance operons. Different variants of metal tolerance (MeT) genes (13 arsA, 6 merA, 1 tcrB) were more commonly recovered from the food-chain (arsA, tcrB) or humans (merA), and were shared with 49 other bacterial taxa. Comparative genomics analysis revealed that MeT genes occurred in heterogeneous operons, at least since the 1900s, with an increasing accretion of antibiotic resistance genes since the 1960's, reflecting diverse antimicrobial pollution. Multiple MeT genes were co-located on the chromosome or conjugative plasmids flanked by elements with high potential for recombination, often along with antibiotic resistance genes. Phenotypic analysis of some isolates carrying MeT genes revealed up to 128× fold increase in the minimum inhibitory concentrations to metals. The main distribution of functional MeT genes among Enterococcus faecium and Enterococcus faecalis from different sources, time spans, and clonal lineages, and their ability to acquire diverse genes from multiple taxa bacterial communities places these species as good candidates to be used as model organisms in future projects aiming at the identification and quantification of bioindicators of metal polluted environments by anthropogenic activities.
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Affiliation(s)
- Andreia Rebelo
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Portugal; Área Técnico-científica de Saúde Ambiental, Escola Superior de Saúde, Instituto Politécnico do Porto, Portugal
| | - Joana Mourão
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Centro de Neurociências e Biologia Celular, Universidade de Coimbra, Portugal; Centro de Inovação em Biomedicina e Biotecnologia, Universidade de Coimbra, Portugal; Instituto de Investigação Interdisciplinar, Universidade de Coimbra, Portugal
| | - Ana R Freitas
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Bárbara Duarte
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Eduarda Silveira
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Centro de Investigação Vasco da Gama (CIVG), Departamento de Ciências Veterinárias, Escola Universitária Vasco da Gama, Coimbra, Portugal; Faculdade de Farmácia, Universidade de Coimbra, Portugal
| | - Antonio Sanchez-Valenzuela
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Servicio de Microbiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Agostinho Almeida
- LAQV/REQUIMTE, Laboratório de Química Aplicada, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Fernando Baquero
- Servicio de Microbiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Teresa M Coque
- Servicio de Microbiologia, Hospital Universitario Ramón y Cajal, Madrid, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBER-ESP), Madrid, Spain; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luísa Peixe
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal
| | - Patrícia Antunes
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal; Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Portugal
| | - Carla Novais
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Portugal.
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14
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Miloud SB, Dziri O, Ferjani S, Ali MM, Mysara M, Boutiba I, Houdt RVAN, Chouchani C. First Description of Various Bacteria Resistant to Heavy Metals and Antibiotics Isolated from Polluted Sites in Tunisia. Pol J Microbiol 2021; 70:161-174. [PMID: 34335797 PMCID: PMC8318066 DOI: 10.33073/pjm-2021-012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 02/05/2021] [Accepted: 02/15/2021] [Indexed: 01/11/2023] Open
Abstract
Environmental bacteria belonging to various families were isolated from polluted water collected from ten different sites in Tunisia. Sites were chosen near industrial and urban areas known for their high degree of pollution. The aim of this study was to investigate cross-resistance between heavy metals (HM), i.e., silver, mercury and copper (Ag, Hg, and Cu), and antibiotics. In an initial screening, 80 isolates were selected on ampicillin, and 39 isolates, retained for further analysis, could grow on a Tris-buffered mineral medium with gluconate as carbon source. Isolates were identified based on their 16S rRNA gene sequence. Results showed the prevalence of antibiotic resistance genes, especially all isolates harbored the blaTEM gene. Some of them (15.38%) harbored blaSHV. Moreover, several were even ESBLs and MBLs-producers, which can threaten the human health. On the other hand, 92.30%, 56.41%, and 51.28% of the isolates harbored the heavy metals resistance genes silE, cusA, and merA, respectively. These genes confer resistance to silver, copper, and mercury. A cross-resistance between antibiotics and heavy metals was detected in 97.43% of our isolates.
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Affiliation(s)
- Samar Ben Miloud
- Research Laboratory of Environmental Sciences and Technologies, Higher Institute of Environmental Sciences and Technologies of Borj-Cedria, University of Carthage, Hammam-Lif, Tunisia.,Laboratory of Microorganisms and Active Biomolecules, Faculty of Sciences of Tunis, University of Tunis El-Manar, Tunis El-Manar, Tunisia.,Research Laboratory Antibiotic Resistance, Faculty of Medicine of Tunis, Tunisia
| | - Olfa Dziri
- Research Laboratory of Environmental Sciences and Technologies, Higher Institute of Environmental Sciences and Technologies of Borj-Cedria, University of Carthage, Hammam-Lif, Tunisia.,Laboratory of Microorganisms and Active Biomolecules, Faculty of Sciences of Tunis, University of Tunis El-Manar, Tunis El-Manar, Tunisia
| | - Sana Ferjani
- Research Laboratory Antibiotic Resistance, Faculty of Medicine of Tunis, Tunisia
| | - Muntasir Md Ali
- Microbiology Unit, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Mohamed Mysara
- Microbiology Unit, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Ilhem Boutiba
- Research Laboratory Antibiotic Resistance, Faculty of Medicine of Tunis, Tunisia
| | - Rob VAN Houdt
- Microbiology Unit, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Chedly Chouchani
- Research Laboratory of Environmental Sciences and Technologies, Higher Institute of Environmental Sciences and Technologies of Borj-Cedria, University of Carthage, Hammam-Lif, Tunisia.,Laboratory of Microorganisms and Active Biomolecules, Faculty of Sciences of Tunis, University of Tunis El-Manar, Tunis El-Manar, Tunisia
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15
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Fong JC, De Guzman BE, Lamborg CH, Sison-Mangus MP. The Mercury-Tolerant Microbiota of the Zooplankton Daphnia Aids in Host Survival and Maintains Fecundity under Mercury Stress. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14688-14699. [PMID: 31747751 DOI: 10.1021/acs.est.9b05305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Many aquatic organisms can thrive in polluted environments by having the genetic capability to withstand suboptimal conditions. However, the contributions of microbiomes under these stressful environments are poorly understood. We investigated whether a mercury-tolerant microbiota can extend its phenotype to its host by ameliorating host survival and fecundity under mercury-stress. We isolated microbiota members from various clones of Daphnia magna, screened for the mercury-biotransforming merA gene, and determined their mercury tolerance levels. We then introduced the mercury-tolerant microbiota, Pseudomonas-10, to axenic D. magna and quantified its merA gene expression, mercury reduction capability, and measured its impact on host survival and fecundity. The expression of the merA gene was up-regulated in Pseudomonas-10, both in isolation and in host-association with mercury exposure. Pseudomonas-10 is also capable of significantly reducing mercury concentration in the medium. Notably, mercury-exposed daphnids containing only Pseudomonas-10 exhibited higher survival and fecundity than mercury-exposed daphnids supplemented with parental microbiome. Our study showed that zooplankton, such as Daphnia, naturally harbor microbiome members that are eco-responsive and tolerant to mercury exposure and can aid in host survival and maintain host fecundity in a mercury-contaminated environment. This study further demonstrates that under stressful environmental conditions, the fitness of the host can depend on the genotype and the phenotype of its microbiome.
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Affiliation(s)
- Jiunn C Fong
- Department of Ocean Sciences and Institute for Marine Sciences , University of California Santa Cruz , Santa Cruz , California 95064 , United States
| | - Brandon E De Guzman
- Department of Ocean Sciences and Institute for Marine Sciences , University of California Santa Cruz , Santa Cruz , California 95064 , United States
| | - Carl H Lamborg
- Department of Ocean Sciences and Institute for Marine Sciences , University of California Santa Cruz , Santa Cruz , California 95064 , United States
| | - Marilou P Sison-Mangus
- Department of Ocean Sciences and Institute for Marine Sciences , University of California Santa Cruz , Santa Cruz , California 95064 , United States
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16
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Multiple Lines of Evidences Reveal Mechanisms Underpinning Mercury Resistance and Volatilization by Stenotrophomonas sp. MA5 Isolated from the Savannah River Site (SRS), USA. Cells 2019; 8:cells8040309. [PMID: 30987227 PMCID: PMC6523443 DOI: 10.3390/cells8040309] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 11/17/2022] Open
Abstract
A largely understudied microbially mediated mercury (Hg) bioremediative pathway includes the volatilization of Hg2+ to Hg0. Therefore, studies on Hg resistant bacteria (HgR), isolated from historically long-term contaminated environments, can serve as models to understand mechanisms underpinning Hg cycling. Towards this end, a mercury resistant bacterial strain, identified as Stenotrophomonas sp., strain MA5, was isolated from Mill Branch on the Savannah River Site (SRS); an Hg-impacted ecosystem. Minimum inhibitory concentration (MIC) analysis showed Hg resistance of up to 20 µg/mL by MA5 with 95% of cells retaining viability. Microcosm studies showed that the strain depleted more than 90% of spiked Hg2+ within the first 24 h of growth and the detection of volatilized mercury indicated that the strain was able to reduce Hg2+ to Hg0. To understand molecular mechanisms of Hg volatilization, a draft whole genome sequence was obtained, annotated and analyzed, which revealed the presence of a transposon-derived mer operon (merRTPADE) in MA5, known to transport and reduce Hg2+ into Hg0. Based on the whole genome sequence of strain MA5, qRT-PCR assays were designed on merRTPADE, we found a ~40-fold higher transcription of mer T, P, A, D and E when cells were exposed to 5 µg/mL Hg2+. Interestingly, strain MA5 increased cellular size as a function of increasing Hg concentrations, which is likely an evolutionary response mechanism to cope with Hg stress. Moreover, metal contaminated environments are shown to co-select for antibiotic resistance. When MA5 was screened for antibiotic resistance, broad resistance against penicillin, streptomycin, tetracycline, ampicillin, rifampicin, and erythromycin was found; this correlated with the presence of multiple gene determinants for antibiotic resistance within the whole genome sequence of MA5. Overall, this study provides an in-depth understanding of the underpinnings of Stenotrophomonas-mercury interactions that facilitate cellular survival in a contaminated soil habitat.
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17
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Evidence of Mercury Methylation and Demethylation by the Estuarine Microbial Communities Obtained in Stable Hg Isotope Studies. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15102141. [PMID: 30274240 PMCID: PMC6210349 DOI: 10.3390/ijerph15102141] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/25/2018] [Accepted: 09/25/2018] [Indexed: 11/17/2022]
Abstract
Microbial activity is a critical factor controlling methylmercury formation in aquatic environments. Microbial communities were isolated from sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and differentiated according to their dependence on oxygen into three groups: aerobic, anaerobic, and sulphate-reducing microbial communities. Their potential to methylate mercury and demethylate methylmercury was evaluated through incubation with isotope-enriched Hg species (199HgCl and CH3201HgCl). The results showed that the isolated microbial communities are actively involved in methylation and demethylation processes. The production of CH3199Hg was positively correlated with sulphate-reducing microbial communities, methylating up to 0.07% of the added 199Hg within 48 h of incubation. A high rate of CH3201Hg degradation was observed and >20% of CH3201Hg was transformed. Mercury removal of inorganic forms was also observed. The results prove the simultaneous occurrence of microbial methylation and demethylation processes and indicate that microorganisms are mainly responsible for methylmercury formation and accumulation in the polluted Tagus Estuary.
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18
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Chen SC, Lin WH, Chien CC, Tsang DCW, Kao CM. Development of a two-stage biotransformation system for mercury-contaminated soil remediation. CHEMOSPHERE 2018; 200:266-273. [PMID: 29494907 DOI: 10.1016/j.chemosphere.2018.02.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Utilization of bacterial volatilization can be problematic to remediate mercury (Hg)-contaminated soils because most of the Hg in soils is bound to soil particles. The objective of this study was to develop a two-stage system (chemical extraction followed by microbial reduction) for Hg-contaminated soil remediation. The tasks were to (1) select the extraction reagents for Hg extraction, (2) assess the effects of extraction reagents on the growth of Hg-reducing bacterial strains, and (3) evaluate the effectiveness of Ca2+ and Mg2+ addition on merA gene (Hg reductase) induction. Bacterial inhibition was observed with the addition of 0.1 M ethylenediaminetetraacetic acid or citric acid. Up to 65% of Hg was biotransformed (Hg concentration = 69 mg/kg) from the soils after a 24 h extraction using 0.5 M ammonium thiosulfate. Ca2+ and Mg2+ were selected because they have the same electric charge as Hg and the studied groundwater contained high concentrations of Ca2+ and Mg2+. Results showed that the addition of 200 mg/L Ca2+ or 650 mg/L Mg2+ could reach effective merA induction. In the two-stage experiment, 120 mg/kg Hg-contaminated soils were extracted with 2 rounds of extraction processes for 10 h using 0.5 M ammonium thiosulfate. Approximately 77% of Hg was extracted from the soils after the first-step extraction process. Up to 81% of Hg2+ was transformed from the washing solution via the biotransformation processes with Enterobacter cloacae addition and Ca2+ and Mg2+ supplementation. The two-stage remedial system has the potential to be developed into a practical technology to remediate Hg-contaminated sites.
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Affiliation(s)
- S C Chen
- Department of Life Sciences, National Central University, Chung-Li, Taiwan
| | - W H Lin
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - C C Chien
- Graduate School of Biotechnology & Bioengineering, Yuan Ze University, Taoyuan City, Taiwan
| | - D C W Tsang
- Department of Civil and Environmental Engr., Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - C M Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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Wang X, He Z, Luo H, Zhang M, Zhang D, Pan X, Gadd GM. Multiple-pathway remediation of mercury contamination by a versatile selenite-reducing bacterium. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 615:615-623. [PMID: 28988098 DOI: 10.1016/j.scitotenv.2017.09.336] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 09/29/2017] [Accepted: 09/30/2017] [Indexed: 06/07/2023]
Abstract
Mercury contamination is a global concern because of its high toxicity, persistence, bioaccumulative nature, long distance transport and wide distribution in the environment. In this study, the efficiency and multiple-pathway remediation mechanisms of Hg2+ by a selenite reducing Escherichia coli was assessed. E. coli can reduce Hg2+ to Hg+ and Hg0 and selenite to selenide at the same time. This makes a multiple-pathway mechanisms for removal of Hg2+ from water in addition to biosorption. It was found that when the original Hg2+ concentration was 40μgL-1, 93.2±2.8% of Hg2+ was removed from solution by E. coli. Of the total Hg removed, it was found that 3.3±0.1% was adsorbed to the bacterium, 2.0±0.5% was bioaccumulated, and 7.3±0.6% was volatilized into the ambient environment, and most (80.6±5.7%) Hg was removed as HgSe and HgCl precipitates and Hg0. On one hand, selenite is reduced to selenide and the latter further reacts with Hg2+ to form HgSe precipitates. On the other hand Hg2+ is successively reduced to Hg+, which forms solid HgCl, and Hg0. This is the report on bacterially transformation of Hg2+ to HgSe, HgCl and Hg0 via multiple pathways. It is suggested that E. coli or other selenite reducing microorganisms are promising candidates for mercury bioremediation of contaminated wastewaters, as well as simultaneous removal of Hg2+ and selenite.
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Affiliation(s)
- Xiaonan Wang
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanfei He
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Hongwei Luo
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ming Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Daoyong Zhang
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiangliang Pan
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Geoffrey Michael Gadd
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, DD15EH, Scotland, UK
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Dash HR, Sahu M, Mallick B, Das S. Functional efficiency of MerA protein among diverse mercury resistant bacteria for efficient use in bioremediation of inorganic mercury. Biochimie 2017; 142:207-215. [DOI: 10.1016/j.biochi.2017.09.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/26/2017] [Indexed: 10/18/2022]
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21
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Diwan V, Purohit M, Chandran S, Parashar V, Shah H, Mahadik VK, Stålsby Lundborg C, Tamhankar AJ. A Three-Year Follow-Up Study of Antibiotic and Metal Residues, Antibiotic Resistance and Resistance Genes, Focusing on Kshipra-A River Associated with Holy Religious Mass-Bathing in India: Protocol Paper. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14060574. [PMID: 28555050 PMCID: PMC5486260 DOI: 10.3390/ijerph14060574] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/24/2017] [Accepted: 05/26/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Antibiotic resistance (ABR) is one of the major health emergencies for global society. Little is known about the ABR of environmental bacteria and therefore it is important to understand ABR reservoirs in the environment and their potential impact on health. METHOD/DESIGN Quantitative and qualitative data will be collected during a 3-year follow-up study of a river associated with religious mass-bathing in Central India. Surface-water and sediment samples will be collected from seven locations at regular intervals for 3 years during religious mass-bathing and in absence of it to monitor water-quality, antibiotic residues, resistant bacteria, antibiotic resistance genes and metals. Approval has been obtained from the Ethics Committee of R.D. Gardi Medical College, Ujjain, India (No. 2013/07/17-311). RESULTS The results will address the issue of antibiotic residues and antibiotic resistance with a focus on a river environment in India within a typical socio-behavioural context of religious mass-bathing. It will enhance our understanding about the relationship between antibiotic residue levels, water-quality, heavy metals and antibiotic resistance patterns in Escherichia coli isolated from river-water and sediment, and seasonal differences that are associated with religious mass-bathing. We will also document, identify and clarify the genetic differences/similarities relating to phenotypic antibiotic resistance in bacteria in rivers during religious mass-bathing or during periods when there is no mass-bathing.
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Affiliation(s)
- Vishal Diwan
- Department of Public Health and Environment, R.D. Gardi Medical College, Ujjain 456006, India.
- Department of Public Health Sciences, Global Health, Health Systems and Policy (HSP): Medicines focusing on antibiotics, Karolinska Institutet, Stockholm 17177, Sweden.
- International Centre for Health Research, Ujjain Charitable Trust Hospital and Research Centre, Ujjain 456001, India.
| | - Manju Purohit
- Department of Public Health Sciences, Global Health, Health Systems and Policy (HSP): Medicines focusing on antibiotics, Karolinska Institutet, Stockholm 17177, Sweden.
- Department of Pathology, R.D. Gardi Medical College, Ujjain 456006, India.
| | - Salesh Chandran
- Department of Public Health Sciences, Global Health, Health Systems and Policy (HSP): Medicines focusing on antibiotics, Karolinska Institutet, Stockholm 17177, Sweden.
- Department of Microbiology, R.D. Gardi Medical College, Ujjain 456003, India.
| | - Vivek Parashar
- Department of Public Health and Environment, R.D. Gardi Medical College, Ujjain 456006, India.
| | - Harshada Shah
- Department of Microbiology, R.D. Gardi Medical College, Ujjain 456003, India.
| | | | - Cecilia Stålsby Lundborg
- Department of Public Health Sciences, Global Health, Health Systems and Policy (HSP): Medicines focusing on antibiotics, Karolinska Institutet, Stockholm 17177, Sweden.
| | - Ashok J Tamhankar
- Department of Public Health Sciences, Global Health, Health Systems and Policy (HSP): Medicines focusing on antibiotics, Karolinska Institutet, Stockholm 17177, Sweden.
- Indian Initiative for Management of Antibiotic Resistance, Department of Environmental Medicine, R.D. Gardi Medical College, Ujjain 456006, India.
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22
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Figueiredo NL, Canário J, O'Driscoll NJ, Duarte A, Carvalho C. Aerobic Mercury-resistant bacteria alter Mercury speciation and retention in the Tagus Estuary (Portugal). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 124:60-67. [PMID: 26461264 DOI: 10.1016/j.ecoenv.2015.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 09/28/2015] [Accepted: 10/01/2015] [Indexed: 06/05/2023]
Abstract
Aerobic mercury-resistant bacteria were isolated from the sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and one natural reserve area (Alcochete) in order to test their capacity to transform mercury. Bacterial species were identified using 16S rRNA amplification and sequencing techniques and the results indicate the prevalence of Bacillus sp. Resistance patterns to mercurial compounds were established by the determination of minimal inhibitory concentrations. Representative Hg-resistant bacteria were further tested for transformation pathways (reduction, volatilization and methylation) in cultures containing mercury chloride. Bacterial Hg-methylation was carried out by Vibrio fluvialis, Bacillus megaterium and Serratia marcescens that transformed 2-8% of total mercury into methylmercury in 48h. In addition, most of the HgR bacterial isolates showed Hg(2+)-reduction andHg(0)-volatilization resulting 6-50% mercury loss from the culture media. In summary, the results obtained under controlled laboratory conditions indicate that aerobic Hg-resistant bacteria from the Tagus Estuary significantly affect both the methylation and reduction of mercury and may have a dual face by providing a pathway for pollution dispersion while forming methylmercury, which is highly toxic for living organisms.
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Affiliation(s)
- Neusa L Figueiredo
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Nelson J O'Driscoll
- Department of Earth & Environmental Sciences, Acadia University, K.C. Irving Environmental Science Center, 32 University Avenue, Wolfville, Nova Scotia, Canada
| | - Aida Duarte
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Cristina Carvalho
- Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
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Vázquez-Rodríguez AI, Hansel CM, Zhang T, Lamborg CH, Santelli CM, Webb SM, Brooks SC. Microbial- and thiosulfate-mediated dissolution of mercury sulfide minerals and transformation to gaseous mercury. Front Microbiol 2015; 6:596. [PMID: 26157421 PMCID: PMC4477176 DOI: 10.3389/fmicb.2015.00596] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/30/2015] [Indexed: 11/13/2022] Open
Abstract
Mercury (Hg) is a toxic heavy metal that poses significant environmental and human health risks. Soils and sediments, where Hg can exist as the Hg sulfide mineral metacinnabar (β-HgS), represent major Hg reservoirs in aquatic environments. Metacinnabar has historically been considered a sink for Hg in all but severely acidic environments, and thus disregarded as a potential source of Hg back to aqueous or gaseous pools. Here, we conducted a combination of field and laboratory incubations to identify the potential for metacinnabar as a source of dissolved Hg within near neutral pH environments and the underpinning (a)biotic mechanisms at play. We show that the abundant and widespread sulfur-oxidizing bacteria of the genus Thiobacillus extensively colonized metacinnabar chips incubated within aerobic, near neutral pH creek sediments. Laboratory incubations of axenic Thiobacillus thioparus cultures led to the release of metacinnabar-hosted Hg(II) and subsequent volatilization to Hg(0). This dissolution and volatilization was greatly enhanced in the presence of thiosulfate, which served a dual role by enhancing HgS dissolution through Hg complexation and providing an additional metabolic substrate for Thiobacillus. These findings reveal a new coupled abiotic-biotic pathway for the transformation of metacinnabar-bound Hg(II) to Hg(0), while expanding the sulfide substrates available for neutrophilic chemosynthetic bacteria to Hg-laden sulfides. They also point to mineral-hosted Hg as an underappreciated source of gaseous elemental Hg to the environment.
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Affiliation(s)
| | - Colleen M Hansel
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| | - Tong Zhang
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| | - Carl H Lamborg
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution Woods Hole, MA, USA
| | - Cara M Santelli
- Department of Mineral Sciences, Smithsonian Institution, National Museum of Natural History Washington, DC, USA
| | - Samuel M Webb
- Stanford Synchrotron Radiation Lightsource Menlo Park, CA, USA
| | - Scott C Brooks
- Environmental Sciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
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24
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Mathew DC, Ho YN, Gicana RG, Mathew GM, Chien MC, Huang CC. A rhizosphere-associated symbiont, Photobacterium spp. strain MELD1, and its targeted synergistic activity for phytoprotection against mercury. PLoS One 2015; 10:e0121178. [PMID: 25816328 PMCID: PMC4376707 DOI: 10.1371/journal.pone.0121178] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/28/2015] [Indexed: 11/24/2022] Open
Abstract
Though heavy metal such as mercury is toxic to plants and microorganisms, the synergistic activity between them may offer benefit for surviving. In this study, a mercury-reducing bacterium, Photobacterium spp. strain MELD1, with an MIC of 33 mg x kg(-1) mercury was isolated from a severely mercury and dioxin contaminated rhizosphere soil of reed (Phragmites australis). While the whole genome sequencing of MELD1 confirmed the presence of a mer operon, the mercury reductase MerA gene showed 99% sequence identity to Vibrio shilloni AK1 and implicates its route resulted from the event of horizontal gene transfer. The efficiency of MELD1 to vaporize mercury (25 mg x kg(-1), 24 h) and its tolerance to toxic metals and xenobiotics such as lead, cadmium, pentachlorophenol, pentachloroethylene, 3-chlorobenzoic acid, 2,3,7,8-tetrachlorodibenzo-p-dioxin and 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin is promising. Combination of a long yard bean (Vigna unguiculata ssp. Sesquipedalis) and strain MELD1 proved beneficial in the phytoprotection of mercury in vivo. The effect of mercury (Hg) on growth, distribution and tolerance was examined in root, shoot, leaves and pod of yard long bean with and without the inoculation of strain MELD1. The model plant inoculated with MELD1 had significant increases in biomass, root length, seed number, and increased mercury uptake limited to roots. Biolog plate assay were used to assess the sole-carbon source utilization pattern of the isolate and Indole-3-acetic acid (IAA) productivity was analyzed to examine if the strain could contribute to plant growth. The results of this study suggest that, as a rhizosphere-associated symbiont, the synergistic activity between the plant and MELD1 can improve the efficiency for phytoprotection, phytostabilization and phytoremediation of mercury.
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Affiliation(s)
- Dony Chacko Mathew
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, R. O. C
| | - Ying-Ning Ho
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, R. O. C
| | - Ronnie Gicaraya Gicana
- Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, R. O. C
| | - Gincy Marina Mathew
- School of Biosciences, Mar Athanasios College for Advanced Studies (MACFAST) BIOCAMPUS, Tiruvalla, Kerala, India
| | - Mei-Chieh Chien
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, R. O. C
| | - Chieh-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, R. O. C
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Rojas Pirela ML, Ball MM, Botello Suárez WA. Antibiotic- and heavy-metal resistance in bacteria isolated from deep subsurface in El Callao region, Venezuela. REVISTA COLOMBIANA DE BIOTECNOLOGÍA 2014. [DOI: 10.15446/rev.colomb.biote.v16n2.41004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Liu YR, Wang JJ, Zheng YM, Zhang LM, He JZ. Patterns of bacterial diversity along a long-term mercury-contaminated gradient in the paddy soils. MICROBIAL ECOLOGY 2014; 68:575-583. [PMID: 24827389 DOI: 10.1007/s00248-014-0430-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/01/2014] [Indexed: 06/03/2023]
Abstract
Mercury (Hg) pollution is usually regarded as an environmental stress in reducing microbial diversity and altering bacterial community structure. However, these results were based on relatively short-term studies, which might obscure the real response of microbial species to Hg contamination. Here, we analysed the bacterial abundance and community composition in paddy soils that have been potentially contaminated by Hg for more than 600 years. Expectedly, the soil Hg pollution significantly influenced the bacterial community structure. However, the bacterial abundance was significantly correlated with the soil organic matter content rather than the total Hg (THg) concentration. The bacterial alpha diversity increased at relatively low levels of THg and methylmercury (MeHg) and subsequently approached a plateau above 4.86 mg kg(-1) THg or 18.62 ng g(-1) MeHg, respectively. Contrasting with the general prediction of decreasing diversity along Hg stress, our results seem to be consistent with the intermediate disturbance hypotheses with the peak biological diversity under intermediate disturbance or stress. This result was partly supported by the inconsistent response of bacterial species to Hg stress. For instance, the relative abundance of Nitrospirae decreased, while that of Gemmatimonadetes increased significantly along the increasing soil THg and MeHg concentrations. In addition, the content of SO(4)(2-), THg, MeHg and soil depth were the four main factors influencing bacterial community structures based on the canonical correspondence analysis (CCA). Overall, our findings provide novel insight into the distribution patterns of bacterial community along the long-term Hg-contaminated gradient in paddy soils.
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Affiliation(s)
- Yu-Rong Liu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
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27
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Pérez-Valdespino A, Celestino-Mancera M, Villegas-Rodríguez VL, Curiel-Quesada E. Characterization of mercury-resistant clinical Aeromonas species. Braz J Microbiol 2014; 44:1279-83. [PMID: 24688523 PMCID: PMC3958199 DOI: 10.1590/s1517-83822013000400036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 04/04/2013] [Indexed: 01/14/2023] Open
Abstract
Mercury-resistant Aeromonas strains isolated from diarrhea were studied. Resistance occurs via mercuric ion reduction but merA and merR genes were only detected in some strains using PCR and dot hybridization. Results indicate a high variability in mer operons in Aeromonas. To our knowledge, this is the first report of mercury-resistant clinical Aeromonas strains.
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Affiliation(s)
- Abigail Pérez-Valdespino
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Martin Celestino-Mancera
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Everardo Curiel-Quesada
- Department of Biochemistry, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
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Rieder SR, Brunner I, Daniel O, Liu B, Frey B. Methylation of mercury in earthworms and the effect of mercury on the associated bacterial communities. PLoS One 2013; 8:e61215. [PMID: 23577209 PMCID: PMC3618111 DOI: 10.1371/journal.pone.0061215] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/07/2013] [Indexed: 11/24/2022] Open
Abstract
Methylmercury compounds are very toxic for most organisms. Here, we investigated the potential of earthworms to methylate inorganic-Hg. We hypothesized that the anaerobic and nutrient-rich conditions in the digestive tracts of earthworm's promote the methylation of Hg through the action of their gut bacteria. Earthworms were either grown in sterile soils treated with an inorganic (HgCl2) or organic (CH3HgCl) Hg source, or were left untreated. After 30 days of incubation, the total-Hg and methyl-Hg concentrations in the soils, earthworms, and their casts were analyzed. The impact of Hg on the bacterial community compositions in earthworms was also studied. Tissue concentrations of methyl-Hg in earthworms grown in soils treated with inorganic-Hg were about six times higher than in earthworms grown in soils without Hg. Concentrations of methyl-Hg in the soils and earthworm casts remained at significantly lower levels suggesting that Hg was mainly methylated in the earthworms. Bacterial communities in earthworms were mostly affected by methyl-Hg treatment. Terminal-restriction fragments (T-RFs) affiliated to Firmicutes were sensitive to inorganic and methyl-Hg, whereas T-RFs related to Betaproteobacteria were tolerant to the Hg treatments. Sulphate-reducing bacteria were detected in earthworms but not in soils.
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Affiliation(s)
- Stephan Raphael Rieder
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Institute for Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland
| | - Ivano Brunner
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Otto Daniel
- Ecotoxicology Group, Agroscope Changins-Wädenswil, Wädenswil, Switzerland
| | - Bian Liu
- Medicine-Pulmonary, Allergy and Critical Care, Columbia University, New York, New York, United States
| | - Beat Frey
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- * E-mail:
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Gulvik CA, Effler TC, Wilhelm SW, Buchan A. De-MetaST-BLAST: a tool for the validation of degenerate primer sets and data mining of publicly available metagenomes. PLoS One 2012. [PMID: 23189198 PMCID: PMC3506598 DOI: 10.1371/journal.pone.0050362] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Development and use of primer sets to amplify nucleic acid sequences of interest is fundamental to studies spanning many life science disciplines. As such, the validation of primer sets is essential. Several computer programs have been created to aid in the initial selection of primer sequences that may or may not require multiple nucleotide combinations (i.e., degeneracies). Conversely, validation of primer specificity has remained largely unchanged for several decades, and there are currently few available programs that allows for an evaluation of primers containing degenerate nucleotide bases. To alleviate this gap, we developed the program De-MetaST that performs an in silico amplification using user defined nucleotide sequence dataset(s) and primer sequences that may contain degenerate bases. The program returns an output file that contains the in silico amplicons. When De-MetaST is paired with NCBI’s BLAST (De-MetaST-BLAST), the program also returns the top 10 nr NCBI database hits for each recovered in silico amplicon. While the original motivation for development of this search tool was degenerate primer validation using the wealth of nucleotide sequences available in environmental metagenome and metatranscriptome databases, this search tool has potential utility in many data mining applications.
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Affiliation(s)
- Christopher A. Gulvik
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - T. Chad Effler
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Steven W. Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Alison Buchan
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail:
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Concomitant antibiotic and mercury resistance among gastrointestinal microflora of feral brook trout, Salvelinus fontinalis. Curr Microbiol 2012; 65:575-82. [PMID: 22850694 DOI: 10.1007/s00284-012-0194-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/22/2012] [Indexed: 10/28/2022]
Abstract
Twenty-nine bacterial isolates representing eight genera from the gastrointestinal tracts of feral brook trout Salvelinus fontinalis (Mitchell) demonstrated multiple maximal antibiotic resistances and concomitant broad-spectrum mercury (Hg) resistance. Equivalent viable plate counts on tryptic soy agar supplemented with either 0 or 25 μM HgCl(2) verified the ubiquity of mercury resistance in this microbial environment. Mercury levels in lake water samples measured 1.5 ng L(-1); mercury concentrations in fish filets ranged from 81.8 to 1,080 ng g(-1) and correlated with fish length. The presence of similar antibiotic and Hg resistance patterns in multiple genera of gastrointestinal microflora supports a growing body of research that multiple selective genes can be transferred horizontally in the presence of an unrelated individual selective pressure. We present data that bioaccumulation of non-point source Hg pollution could be a selective pressure to accumulate both antibiotic and Hg resistant bacteria.
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31
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Mercury resistance and mercuric reductase activities and expression among chemotrophic thermophilic Aquificae. Appl Environ Microbiol 2012; 78:6568-75. [PMID: 22773655 DOI: 10.1128/aem.01060-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mercury (Hg) resistance (mer) by the reduction of mercuric to elemental Hg is broadly distributed among the Bacteria and Archaea and plays an important role in Hg detoxification and biogeochemical cycling. MerA is the protein subunit of the homodimeric mercuric reductase (MR) enzyme, the central function of the mer system. MerA sequences in the phylum Aquificae form the deepest-branching lineage in Bayesian phylogenetic reconstructions of all known MerA homologs. We therefore hypothesized that the merA homologs in two thermophilic Aquificae, Hydrogenobaculum sp. strain Y04AAS1 (AAS1) and Hydrogenivirga sp. strain 128-5-R1-1 (R1-1), specified Hg resistance. Results supported this hypothesis, because strains AAS1 and R1-1 (i) were resistant to >10 μM Hg(II), (ii) transformed Hg(II) to Hg(0) during cellular growth, and (iii) possessed Hg-dependent NAD(P)H oxidation activities in crude cell extracts that were optimal at temperatures corresponding with the strains' optimal growth temperatures, 55°C for AAS1 and 70°C for R1-1. While these characteristics all conformed with the mer system paradigm, expression of the Aquificae mer operons was not induced by exposure to Hg(II) as indicated by unity ratios of merA transcripts, normalized to gyrA transcripts for hydrogen-grown AAS1 cultures, and by similar MR specific activities in thiosulfate-grown cultures with and without Hg(II). The Hg(II)-independent expression of mer in the deepest-branching lineage of MerA from bacteria whose natural habitats are Hg-rich geothermal environments suggests that regulated expression of mer was a later innovation likely in environments where microorganisms were intermittently exposed to toxic concentrations of Hg.
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Wang Y, Wiatrowski HA, John R, Lin CC, Young LY, Kerkhof LJ, Yee N, Barkay T. Impact of mercury on denitrification and denitrifying microbial communities in nitrate enrichments of subsurface sediments. Biodegradation 2012; 24:33-46. [PMID: 22678127 DOI: 10.1007/s10532-012-9555-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 05/04/2012] [Indexed: 10/28/2022]
Abstract
The contamination of groundwater with mercury (Hg) is an increasing problem worldwide. Yet, little is known about the interactions of Hg with microorganisms and their processes in subsurface environments. We tested the impact of Hg on denitrification in nitrate reducing enrichment cultures derived from subsurface sediments from the Oak Ridge Integrated Field Research Challenge site, where nitrate is a major contaminant and where bioremediation efforts are in progress. We observed an inverse relationship between Hg concentrations and onset and rates of denitrification in nitrate enrichment cultures containing between 53 and 1.1 μM of inorganic Hg; higher Hg concentrations increasingly extended the time to onset of denitrification and inhibited denitrification rates. Microbial community complexity, as indicated by terminal restriction fragment length polymorphism (tRFLP) analysis of the 16S rRNA genes, declined with increasing Hg concentrations; at the 312 nM Hg treatment, a single tRFLP peak was detected representing a culture of Bradyrhizobium sp. that possessed the merA gene indicating a potential for Hg reduction. A culture identified as Bradyrhizobium sp. strain FRC01 with an identical 16S rRNA sequence to that of the enriched peak in the tRFLP patterns, reduced Hg(II) to Hg(0) and carried merA whose amino acid sequence has 97 % identity to merA from the Proteobacteria and Firmicutes. This study demonstrates that in subsurface sediment incubations, Hg may inhibit denitrification and that inhibition may be alleviated when Hg resistant denitrifying Bradyrhizobium spp. detoxify Hg by its reduction to the volatile elemental form.
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Affiliation(s)
- Yanping Wang
- Department of Biochemistry and Microbiology, Rutgers University, 223C Lipman Hall, 76 Lipman Dr., New Brunswick, NJ 08901, USA.
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KHODIJAH CHAERUN SITI, HASNI SAKINAH, SANWANI EDY, RAMDANI MOEIS MAELITA. Mercury (Hg)-Resistant Bacteria in Hg-Polluted Gold Mine Sites of Bandung, West Java Province, Indonesia. MICROBIOLOGY INDONESIA 2012. [DOI: 10.5454/mi.6.2.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Mercury-resistant rhizobial bacteria isolated from nodules of leguminous plants growing in high Hg-contaminated soils. Appl Microbiol Biotechnol 2012; 96:543-54. [DOI: 10.1007/s00253-011-3832-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 12/07/2011] [Accepted: 12/09/2011] [Indexed: 10/14/2022]
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Liu YR, He JZ, Zhang LM, Zheng YM. Effects of long-term fertilization on the diversity of bacterial mercuric reductase gene in a Chinese upland soil. J Basic Microbiol 2011; 52:35-42. [DOI: 10.1002/jobm.201100211] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 07/21/2011] [Indexed: 11/12/2022]
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Wang Y, Boyd E, Crane S, Lu-Irving P, Krabbenhoft D, King S, Dighton J, Geesey G, Barkay T. Environmental conditions constrain the distribution and diversity of archaeal merA in Yellowstone National Park, Wyoming, U.S.A. MICROBIAL ECOLOGY 2011; 62:739-752. [PMID: 21713435 DOI: 10.1007/s00248-011-9890-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 06/04/2011] [Indexed: 05/31/2023]
Abstract
The distribution and phylogeny of extant protein-encoding genes recovered from geochemically diverse environments can provide insight into the physical and chemical parameters that led to the origin and which constrained the evolution of a functional process. Mercuric reductase (MerA) plays an integral role in mercury (Hg) biogeochemistry by catalyzing the transformation of Hg(II) to Hg(0). Putative merA sequences were amplified from DNA extracts of microbial communities associated with mats and sulfur precipitates from physicochemically diverse Hg-containing springs in Yellowstone National Park, Wyoming, using four PCR primer sets that were designed to capture the known diversity of merA. The recovery of novel and deeply rooted MerA lineages from these habitats supports previous evidence that indicates merA originated in a thermophilic environment. Generalized linear models indicate that the distribution of putative archaeal merA lineages was constrained by a combination of pH, dissolved organic carbon, dissolved total mercury and sulfide. The models failed to identify statistically well supported trends for the distribution of putative bacterial merA lineages as a function of these or other measured environmental variables, suggesting that these lineages were either influenced by environmental parameters not considered in the present study, or the bacterial primer sets were designed to target too broad of a class of genes which may have responded differently to environmental stimuli. The widespread occurrence of merA in the geothermal environments implies a prominent role for Hg detoxification in these environments. Moreover, the differences in the distribution of the merA genes amplified with the four merA primer sets suggests that the organisms putatively engaged in this activity have evolved to occupy different ecological niches within the geothermal gradient.
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Affiliation(s)
- Yanping Wang
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
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Carvalho G, Almeida B, Fradinho J, Oehmen A, Reis MAM, Crespo MTB. Microbial characterization of mercury-reducing mixed cultures enriched with different carbon sources. Microbes Environ 2011; 26:293-300. [PMID: 21685715 DOI: 10.1264/jsme2.me11112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The use of mixed microbial cultures enriched for biological mercury removal is explored in this paper, focusing on the ecological shifts occurring throughout acclimatization to mercury and on the long-term stability of four microbial enrichments. The 16S rRNA genetic profiles obtained by denaturing gradient gel electrophoresis (DGGE) revealed that the glucose and ethanol cultures had similar profiles, whereas the acetate cultures diverged into a totally dissimilar cluster. Quantification of the merA gene copies in each enrichment showed higher values for the glucose culture, followed by the ethanol and then the acetate cultures, which was consistent with the mercury removal performance throughout the study. Isolates were obtained from the four cultures and analyzed with respect to their genetic (16S rRNA) and functional (merA) phylogenies in order to identify mercury-resistant species enriched with different carbon sources. All mercury-resistant isolates obtained from the glucose and ethanol cultures belonged to the Gammaproteobacteria, whereas acetate cultures also contained members of other phyla, with differences in merA sequences. Higher phylogenetic than functional diversity of the isolates, together with increasing merA copies even after culture stabilisation, highlight the role of horizontal gene transfer in the acclimatization process.
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Affiliation(s)
- Gilda Carvalho
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.
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Pitkänen LK, Tamminen M, Hynninen A, Karkman A, Corander J, Kotilainen A, Virta M. Fish Farming Affects the Abundance and Diversity of the Mercury Resistance Gene merA in Marine Sediments. Microbes Environ 2011; 26:205-11. [DOI: 10.1264/jsme2.me11119] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Leena K. Pitkänen
- University of Helsinki, Department of Food and Environmental Sciences
| | - Manu Tamminen
- University of Helsinki, Department of Food and Environmental Sciences
| | - Anu Hynninen
- University of Helsinki, Department of Food and Environmental Sciences
| | - Antti Karkman
- University of Helsinki, Department of Food and Environmental Sciences
| | | | | | - Marko Virta
- University of Helsinki, Department of Food and Environmental Sciences
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Bafana A. Mercury resistance in Sporosarcina sp. G3. Biometals 2010; 24:301-9. [DOI: 10.1007/s10534-010-9396-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 12/08/2010] [Indexed: 11/30/2022]
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Community genomic and proteomic analyses of chemoautotrophic iron-oxidizing "Leptospirillum rubarum" (Group II) and "Leptospirillum ferrodiazotrophum" (Group III) bacteria in acid mine drainage biofilms. Appl Environ Microbiol 2009; 75:4599-615. [PMID: 19429552 DOI: 10.1128/aem.02943-08] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We analyzed near-complete population (composite) genomic sequences for coexisting acidophilic iron-oxidizing Leptospirillum group II and III bacteria (phylum Nitrospirae) and an extrachromosomal plasmid from a Richmond Mine, Iron Mountain, CA, acid mine drainage biofilm. Community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of Leptospirillum groups II and III, respectively, and 20% of the predicted plasmid proteins. The bacteria share 92% 16S rRNA gene sequence identity and >60% of their genes, including integrated plasmid-like regions. The extrachromosomal plasmid carries conjugation genes with detectable sequence similarity to genes in the integrated conjugative plasmid, but only those on the extrachromosomal element were identified by proteomics. Both bacterial groups have genes for community-essential functions, including carbon fixation and biosynthesis of vitamins, fatty acids, and biopolymers (including cellulose); proteomic analyses reveal these activities. Both Leptospirillum types have multiple pathways for osmotic protection. Although both are motile, signal transduction and methyl-accepting chemotaxis proteins are more abundant in Leptospirillum group III, consistent with its distribution in gradients within biofilms. Interestingly, Leptospirillum group II uses a methyl-dependent and Leptospirillum group III a methyl-independent response pathway. Although only Leptospirillum group III can fix nitrogen, these proteins were not identified by proteomics. The abundances of core proteins are similar in all communities, but the abundance levels of unique and shared proteins of unknown function vary. Some proteins unique to one organism were highly expressed and may be key to the functional and ecological differentiation of Leptospirillum groups II and III.
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Comparative effects of mercury contamination and wastewater effluent input on Gram-negative merA gene abundance in mudflats of an anthropized estuary (Seine, France): a microcosm approach. Res Microbiol 2009; 160:10-8. [DOI: 10.1016/j.resmic.2008.10.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 10/02/2008] [Accepted: 10/08/2008] [Indexed: 11/20/2022]
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De Lipthay JR, Rasmussen LD, Oregaard G, Simonsen K, Bahl MI, Kroer N, Sørensen SÃJ. Acclimation of subsurface microbial communities to mercury. FEMS Microbiol Ecol 2008; 65:145-55. [DOI: 10.1111/j.1574-6941.2008.00501.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Ramond JB, Berthe T, Lafite R, Deloffre J, Ouddane B, Petit F. Relationships between hydrosedimentary processes and occurrence of mercury-resistant bacteria (merA) in estuary mudflats (Seine, France). MARINE POLLUTION BULLETIN 2008; 56:1168-1176. [PMID: 18381217 DOI: 10.1016/j.marpolbul.2008.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/08/2008] [Accepted: 02/12/2008] [Indexed: 05/26/2023]
Abstract
The Seine estuary (France) is one of the world's macrotidal systems that is most contaminated with heavy metals. To study the mercury-resistant bacterial community in such an environment, we have developed a molecular tool, based on competitive PCR, enabling the quantification of Gram-negative merA gene abundance. The occurrence of the Gram-negative merA gene in relation with the topology (erosion/deposit periods) and the mercury contamination of three contrasted mudflats was investigated through a multidisciplinary approach and compared with a non-anthropized site (Authie, France). The higher abundance of the Gram-negative merA gene in the Seine estuary mudflats indicates a relationship between the degree of anthropization and the abundance of the merA gene in the mudflat sediments. In the Seine mudflats, the maxima of abundance are always located in fresh sediment deposits. Therefore, the abundance is closely related with the hydrosedimentary processes, which thus seem to be determining factors in the occurrence of the Gram-negative merA gene in the surface sediments of the Seine's mudflat.
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Affiliation(s)
- Jean-Baptiste Ramond
- Université de Rouen - CNRS UMR 6143, Morphodynamique Continentale et Côtière (M2C), Groupe de Microbiologie, 76821 Mont Saint Aignan Cedex, France
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Cultivation of hard-to-culture subsurface mercury-resistant bacteria and discovery of new merA gene sequences. Appl Environ Microbiol 2008; 74:3795-803. [PMID: 18441111 DOI: 10.1128/aem.00049-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mercury-resistant bacteria may be important players in mercury biogeochemistry. To assess the potential for mercury reduction by two subsurface microbial communities, resistant subpopulations and their merA genes were characterized by a combined molecular and cultivation-dependent approach. The cultivation method simulated natural conditions by using polycarbonate membranes as a growth support and a nonsterile soil slurry as a culture medium. Resistant bacteria were pregrown to microcolony-forming units (mCFU) before being plated on standard medium. Compared to direct plating, culturability was increased up to 2,800 times and numbers of mCFU were similar to the total number of mercury-resistant bacteria in the soils. Denaturing gradient gel electrophoresis analysis of DNA extracted from membranes suggested stimulation of growth of hard-to-culture bacteria during the preincubation. A total of 25 different 16S rRNA gene sequences were observed, including Alpha-, Beta-, and Gammaproteobacteria; Actinobacteria; Firmicutes; and Bacteroidetes. The diversity of isolates obtained by direct plating included eight different 16S rRNA gene sequences (Alpha- and Betaproteobacteria and Actinobacteria). Partial sequencing of merA of selected isolates led to the discovery of new merA sequences. With phylum-specific merA primers, PCR products were obtained for Alpha- and Betaproteobacteria and Actinobacteria but not for Bacteroidetes and Firmicutes. The similarity to known sequences ranged between 89 and 95%. One of the sequences did not result in a match in the BLAST search. The results illustrate the power of integrating advanced cultivation methodology with molecular techniques for the characterization of the diversity of mercury-resistant populations and assessing the potential for mercury reduction in contaminated environments.
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Basile LA, Erijman L. Quantitative assessment of phenol hydroxylase diversity in bioreactors using a functional gene analysis. Appl Microbiol Biotechnol 2008; 78:863-72. [DOI: 10.1007/s00253-008-1351-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 12/25/2007] [Accepted: 01/03/2008] [Indexed: 11/30/2022]
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High diversity of bacterial mercuric reductase genes from surface and sub-surface floodplain soil (Oak Ridge, USA). ISME JOURNAL 2007; 1:453-67. [PMID: 18043664 DOI: 10.1038/ismej.2007.56] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA was extracted from different depth soils (0-5, 45-55 and 90-100 cm below surface) sampled at Lower East Fork Poplar Creek floodplain (LEFPCF), Oak Ridge (TN, USA). The presence of merA genes, encoding the mercuric reductase, the key enzyme in detoxification of mercury in bacteria, was examined by PCR targeting Actinobacteria, Firmicutes or beta/gamma-Proteobacteria. beta/gamma-Proteobacteria merA genes were successfully amplified from all soils, whereas Actinobacteria were amplified only from surface soil. merA clone libraries were constructed and sequenced. beta/gamma-Proteobacteria sequences revealed high diversity in all soils, but limited vertical similarity. Less than 20% of the operational taxonomic units (OTU) (DNA sequences > or = 95% identical) were shared between the different soils. Only one of the 62 OTU was > or = 95% identical to a GenBank sequence, highlighting that cultivated bacteria are not representative of what is found in nature. Fewer merA sequences were obtained from the Actinobacteria, but these were also diverse, and all were different from GenBank sequences. A single clone was most closely related to merA of alpha-Proteobacteria. An alignment of putative merA genes of genome sequenced mainly marine alpha-Proteobacteria was used for design of merA primers. PCR amplification of soil alpha-Proteobacteria isolates and sequencing revealed that they were very different from the genome-sequenced bacteria (only 62%-66% identical at the amino-acid level), although internally similar. In light of the high functional diversity of mercury resistance genes and the limited vertical distribution of shared OTU, we discuss the role of horizontal gene transfer as a mechanism of bacterial adaptation to mercury.
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Chatziefthimiou AD, Crespo-Medina M, Wang Y, Vetriani C, Barkay T. The isolation and initial characterization of mercury resistant chemolithotrophic thermophilic bacteria from mercury rich geothermal springs. Extremophiles 2007; 11:469-79. [PMID: 17401541 DOI: 10.1007/s00792-007-0065-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Accepted: 12/10/2006] [Indexed: 10/23/2022]
Abstract
Mercury rich geothermal springs are likely environments where mercury resistance is critical to microbial life and where microbe-mercury interactions may have evolved. Eleven facultative thermophilic and chemolithoautotrophic, thiosulfate oxidizing bacteria were isolated from thiosulfate enrichments of biofilms from mercury rich hot sulfidic springs in Mount Amiata, Italy. Some strains were highly resistant to mercury (>or=200 muM HgCl(2)) regardless of its presence or absence during primary enrichments, and three reduced ionic mercury to its elemental form. The gene encoding for the mercuric reductase enzyme (MerA), was amplified by PCR from seven strains. However, one highly resistant strain did not reduce mercury nor carried merA, suggesting an alternative resistance mechanism. All strains were members of the order Bacillales and were most closely related to previously described thermophiles belonging to the Firmicutes. Phylogenetic analyses clustered the MerA of the isolates in two supported novel nodes within the Firmicutes lineage and a comparison with the 16S rRNA gene tree suggested at least one case of horizontal gene transfer. Overall, the results show that the thermophilic thiosulfate oxidizing isolates were adapted to life in presence of mercury mostly, but not exclusively, by possessing MerA. These findings suggest that reduction of mercury by chemolithotrophic thermophilic bacteria may mobilize mercury from sulfur and iron deposits in geothermal environments.
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Affiliation(s)
- Aspassia D Chatziefthimiou
- Department of Biochemistry and Microbiology, Rutgers University, 76 Lipman Dr., New Brunswick, NJ 08901, USA
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Poulain AJ, Ní Chadhain SM, Ariya PA, Amyot M, Garcia E, Campbell PGC, Zylstra GJ, Barkay T. Potential for mercury reduction by microbes in the high arctic. Appl Environ Microbiol 2007; 73:2230-8. [PMID: 17293515 PMCID: PMC1855672 DOI: 10.1128/aem.02701-06] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The contamination of polar regions due to the global distribution of anthropogenic pollutants is of great concern because it leads to the bioaccumulation of toxic substances, methylmercury among them, in Arctic food chains. Here we present the first evidence that microbes in the high Arctic possess and express diverse merA genes, which specify the reduction of ionic mercury [Hg(II)] to the volatile elemental form [Hg(0)]. The sampled microbial biomass, collected from microbial mats in a coastal lagoon and from the surface of marine macroalgae, was comprised of bacteria that were most closely related to psychrophiles that had previously been described in polar environments. We used a kinetic redox model, taking into consideration photoredox reactions as well as mer-mediated reduction, to assess if the potential for Hg(II) reduction by Arctic microbes can affect the toxicity and environmental mobility of mercury in the high Arctic. Results suggested that mer-mediated Hg(II) reduction could account for most of the Hg(0) that is produced in high Arctic waters. At the surface, with only 5% metabolically active cells, up to 68% of the mercury pool was resolved by the model as biogenic Hg(0). At a greater depth, because of incident light attenuation, the significance of photoredox transformations declined and merA-mediated activity could account for up to 90% of Hg(0) production. These findings highlight the importance of microbial redox transformations in the biogeochemical cycling, and thus the toxicity and mobility, of mercury in polar regions.
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Affiliation(s)
- Alexandre J Poulain
- Groupe de Recherche Inter-universitaire en Limnologie (GRIL), Département des Sciences Biologiques, Université de Montréal, C. P. 6128, Succursale Centre-Ville, Pavillon Marie-Victorin, Montréal, Québec, Canada H3C 3J7
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