1
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Scuvée D, Goñi-Urriza M, Gassie C, Khalfaoui-Hassani B, Guyoneaud R. Consortia cultivation of the Desulfobacterota from macrophyte periphyton: tool for increasing the cultivation of microorganisms involved in mercury methylation. Microbiol Res 2023; 273:127415. [PMID: 37247586 DOI: 10.1016/j.micres.2023.127415] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/02/2023] [Accepted: 05/17/2023] [Indexed: 05/31/2023]
Abstract
Invasive macrophytes are a persistent environmental problem in aquatic ecosystems. They also cause potential health issues, since periphyton colonizing their aquatic roots are hot spot of mercury methylation. Because periphytons are at the base of the trophic chain, the produced methylmercury is bioamplified through the food webs. In this work, a consortia cultivation approach was applied in order to investigate methylators in the periphyton of Ludwigia sp., an invasive macrophyte. Five growth conditions were used in order to favor the growth of different sulfate reducers, the major mercury methylators in this periphyton. A total of 33 consortia containing putative Hg methylators were obtained. Based on the amino acid sequences of HgcA (essential enzyme for Hg methylation), the obtained consortia could be subdivided into five main clusters, affiliated with Desulfovibrionaceae, Desulfobulbaceae and Syntrophobacteraceae. The main cluster, related to Desulfovibrionaceae, showed the highest sequence diversity; notwithstanding most of the sequences of this cluster showed no close representatives. Through the consortia approach, species thus far uncultivated were cultivated. The successful cultivation of these species was probably possible through the metabolites produced by other members of the consortium. The analysis of the microbial composition of the consortia uncover certain microbial interactions that may exist within this complex environment.
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Affiliation(s)
- Diva Scuvée
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM UMR5254, Environmental Microbiology and Chemistry, 64000 Pau, France
| | - Marisol Goñi-Urriza
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM UMR5254, Environmental Microbiology and Chemistry, 64000 Pau, France
| | - Claire Gassie
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM UMR5254, Environmental Microbiology and Chemistry, 64000 Pau, France
| | - Bahia Khalfaoui-Hassani
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM UMR5254, Environmental Microbiology and Chemistry, 64000 Pau, France
| | - Rémy Guyoneaud
- Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, IPREM UMR5254, Environmental Microbiology and Chemistry, 64000 Pau, France.
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2
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Schneider L, Fisher JA, Diéguez MC, Fostier AH, Guimaraes JRD, Leaner JJ, Mason R. A synthesis of mercury research in the Southern Hemisphere, part 1: Natural processes. AMBIO 2023; 52:897-917. [PMID: 36943620 PMCID: PMC10073387 DOI: 10.1007/s13280-023-01832-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/30/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Recent studies demonstrate a short 3-6-month atmospheric lifetime for mercury (Hg). This implies Hg emissions are predominantly deposited within the same hemisphere in which they are emitted, thus placing increasing importance on considering Hg sources, sinks and impacts from a hemispheric perspective. In the absence of comprehensive Hg data from the Southern Hemisphere (SH), estimates and inventories for the SH have been drawn from data collected in the NH, with the assumption that the NH data are broadly applicable. In this paper, we centre the uniqueness of the SH in the context of natural biogeochemical Hg cycling, with focus on the midlatitudes and tropics. Due to its uniqueness, Antarctica warrants an exclusive review of its contribution to the biogeochemical cycling of Hg and is therefore excluded from this review. We identify and describe five key natural differences between the hemispheres that affect the biogeochemical cycling of Hg: biome heterogeneity, vegetation type, ocean area, methylation hotspot zones and occurence of volcanic activities. We review the current state of knowledge of SH Hg cycling within the context of each difference, as well as the key gaps that impede our understanding of natural Hg cycling in the SH. The differences demonstrate the limitations in using NH data to infer Hg processes and emissions in the SH.
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Affiliation(s)
- Larissa Schneider
- School of Culture, History and Language. Australian National University, Coombs Bld 9 Fellows Rd, Acton. Canberra, ACT 2601 Australia
| | - Jenny A. Fisher
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522 Australia
| | - María C. Diéguez
- Instituto de Investigaciones en Biodiversidad y Medioambiente (Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del Comahue), 1250 San Carlos de Bariloche (8400), Quintral Argentina
| | - Anne-Hélène Fostier
- Instituto de Química/Unicamp, Rua Josué de Castro, s/n – Cidade Universitária, Campinas, SP 13083-970 Brazil
| | - Jean R. D. Guimaraes
- Lab. de Traçadores, Inst. de Biofísica, Bloco G, CCS (Centro de Ciências da Saúde), Av. Carlos Chagas Filho 373, Rio de Janeiro, Ilha do Fundão CEP 21941-902 Brazil
| | - Joy J. Leaner
- Department of Environmental Affairs and Development Planning, Western Cape Government, 1 Dorp Street, Western Cape, Cape Town, 8001 South Africa
| | - Robert Mason
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340 USA
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3
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Chen Y, Guo Y, Liu Y, Xiang Y, Liu G, Zhang Q, Yin Y, Cai Y, Jiang G. Advances in bacterial whole-cell biosensors for the detection of bioavailable mercury: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161709. [PMID: 36682565 DOI: 10.1016/j.scitotenv.2023.161709] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/29/2022] [Accepted: 01/15/2023] [Indexed: 06/17/2023]
Abstract
Mercury (Hg) and its organic compounds, especially monomethylmercury (MeHg), cause major damage to the ecosystem and human health. In surface water or sediments, microorganisms play a crucial role in the methylation and demethylation of Hg. Given that Hg transformation processes are intracellular reactions, accurate assessment of the bioavailability of Hg(II)/MeHg in the environment, particularly for microorganisms, is of major importance. Compared with traditional analytical methods, bacterial whole-cell biosensors (BWCBs) provide a more accurate, convenient, and cost-effective strategy to assess the environmental risks of Hg(II)/MeHg. This Review summarizes recent progress in the application of BWCBs in the detection of bioavailable Hg(II)/MeHg, providing insight on current challenges and strategies. The principle and components of BWCBs for Hg(II)/MeHg bioavailability analysis are introduced. Furthermore, the impact of water chemical factors on the bioavailability of Hg is discussed as are future perspectives of BWCBs in bioavailable Hg analysis and optimization of BWCBs.
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Affiliation(s)
- Yueqian Chen
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| | - Yingying Guo
- Laboratory of Environmental Nanotechnology and Health, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yanwei Liu
- Laboratory of Environmental Nanotechnology and Health, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yuping Xiang
- Laboratory of Environmental Nanotechnology and Health, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States of America
| | - Qinghua Zhang
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yongguang Yin
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China; Laboratory of Environmental Nanotechnology and Health, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yong Cai
- Laboratory of Environmental Nanotechnology and Health, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, United States of America
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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4
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Barrouilhet S, Monperrus M, Tessier E, Khalfaoui-Hassani B, Guyoneaud R, Isaure MP, Goñi-Urriza M. Effect of exogenous and endogenous sulfide on the production and the export of methylmercury by sulfate-reducing bacteria. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:3835-3846. [PMID: 35953752 DOI: 10.1007/s11356-022-22173-y] [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: 11/24/2021] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Mercury (Hg) is a global pollutant of environmental and health concern; its methylated form, methylmercury (MeHg), is a potent neurotoxin. Sulfur-containing molecules play a role in MeHg production by microorganisms. While sulfides are considered to limit Hg methylation, sulfate and cysteine were shown to favor this process. However, these two forms can be endogenously converted by microorganisms into sulfide. Here, we explore the effect of sulfide (produced by the cell or supplied exogenously) on Hg methylation. For this purpose, Pseudodesulfovibrio hydrargyri BerOc1 was cultivated in non-sulfidogenic conditions with addition of cysteine and sulfide as well as in sulfidogenic conditions. We report that Hg methylation depends on sulfide concentration in the culture and the sulfides produced by cysteine degradation or sulfate reduction could affect the Hg methylation pattern. Hg methylation was independent of hgcA expression. Interestingly, MeHg production was maximal at 0.1-0.5 mM of sulfides. Besides, a strong positive correlation between MeHg in the extracellular medium and the increase of sulfide concentrations was observed, suggesting a facilitated MeHg export with sulfide and/or higher desorption from the cell. We suggest that sulfides (exogenous or endogenous) play a key role in controlling mercury methylation and should be considered when investigating the impact of Hg in natural environments.
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Affiliation(s)
- Sophie Barrouilhet
- Universite de Pau Et Des Pays de L'Adour, E2S UPPA, CNRS, IPREM UMR 5254, Pau, France
| | - Mathilde Monperrus
- Universite de Pau Et Des Pays de L'Adour, E2S UPPA, CNRS, IPREM UMR 5254, Anglet, France
| | - Emmanuel Tessier
- Universite de Pau Et Des Pays de L'Adour, E2S UPPA, CNRS, IPREM UMR 5254, Pau, France
| | | | - Rémy Guyoneaud
- Universite de Pau Et Des Pays de L'Adour, E2S UPPA, CNRS, IPREM UMR 5254, Pau, France
| | - Marie-Pierre Isaure
- Universite de Pau Et Des Pays de L'Adour, E2S UPPA, CNRS, IPREM UMR 5254, Pau, France
| | - Marisol Goñi-Urriza
- Universite de Pau Et Des Pays de L'Adour, E2S UPPA, CNRS, IPREM UMR 5254, Pau, France.
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5
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Gouvêa AL, Gracindo Silva M, Cabral B, Martinez CG, Lauthartte LC, Rodrigues Bastos W, Kurtenbach E. Progressive resistance exercise prevents muscle strength loss due to muscle atrophy induced by methylmercury systemic intoxication. JCSM CLINICAL REPORTS 2021. [DOI: 10.1002/crt2.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- André Luiz Gouvêa
- Instituto de Biofísica Carlos Chagas Filho Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
- Instituto de Bioquímica Médica Leopoldo de Meis Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | - Marcia Gracindo Silva
- Instituto de Biofísica Carlos Chagas Filho Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
- Instituto de Bioquímica Médica Leopoldo de Meis Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | - Bruno Cabral
- Instituto de Biofísica Carlos Chagas Filho Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | - Camila Guerra Martinez
- Instituto de Biofísica Carlos Chagas Filho Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
| | | | - Waderley Rodrigues Bastos
- Laboratório de Biogeoquímica Ambiental Universidade Federal de Rondônia Porto Velho Rondônia 76801‐974 Brazil
| | - Eleonora Kurtenbach
- Instituto de Biofísica Carlos Chagas Filho Universidade Federal do Rio de Janeiro Rio de Janeiro Rio de Janeiro 21941‐902 Brazil
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6
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Influence of Macrophyte and Gut Microbiota on Mercury Contamination in Fish: A Microcosms Study. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10041500] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The freshwater lakes of southwestern France are subject to the development of invasive macrophytes which are associated with mercury (Hg) contamination of the food web. The aim of this study was to determine the bioavailability of methylmercury (MeHg) produced by plant roots in aquatic ecosystems. A microcosm experiment was performed using isotopically enriched inorganic Hg at environmental concentrations (1 µg 199IHg·L−1). For all conditions, total Hg in fish as well as Hg species associated with different compartments (water, sediments, plant roots, fish) were analyzed by gas chromatography-inductively coupled plasma-mass spectrometry (GC-ICP-MS). In addition, sediment, plants, and fish gut microbiota were studied by MiSEQ sequencing. Some strains were isolated and tested for their ability to methylate Hg. The results revealed 199MeHg production in plant roots and the presence of this form in fish (tissues and gut), highlighting a MeHg trophic transfer. Moreover, methylator bacteria were identified from the gut contents of the fish when they were in the presence of plants. Some of them were related to bacteria found in the plant roots. On the basis of these results, the transfer of MeHg and bacteria from plants to fish is highlighted; in addition, Hg methylation is strongly suspected in the fish gut, potentially increasing the Hg bioaccumulation.
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7
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Schwartz GE, Olsen TA, Muller KA, Brooks SC. Ecosystem Controls on Methylmercury Production by Periphyton Biofilms in a Contaminated Stream: Implications for Predictive Modeling. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2019; 38:2426-2435. [PMID: 31365146 DOI: 10.1002/etc.4551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/12/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Periphyton biofilms produce a substantial fraction of the overall monomethylmercury (MMHg) flux in East Fork Poplar Creek, an industrially contaminated, freshwater creek in Oak Ridge, Tennessee. We examined periphyton MMHg production across seasons, locations, and light conditions using mercury stable isotopes. Methylation and demethylation rate potentials (km, trans av and kd, trans av , respectively) were calculated using a transient availability kinetic model. Light exposure and season were significant predictors of km, trans av , with greater values in full light exposure and in the summer. Season, light exposure, and location were significant predictors of kd, trans av , which was highest in dark conditions, in the spring, and at the upstream location. Light exposure was the controlling factor for net MMHg production, with positive production for periphyton grown under full light exposure and net demethylation for periphyton grown in the dark. Ambient MMHg and km, trans av were significantly correlated. Transient availability rate potentials were 15 times higher for km and 9 times higher for kd compared to full availability rate potentials (km, full av and kd, full av ) calculated at 1 d. No significant model for the prediction of km, full av or kd, full av could be constructed using light, season, and location. In addition, there were no significant differences among treatments for the full availability km, full av , kd, full av , or net MMHg calculated using the full availability rate potentials. km, full av was not correlated with ambient MMHg concentrations. The present results underscore the importance of applying transient availability kinetics to MMHg production data when estimating MMHg production potential and flux. Environ Toxicol Chem 2019;38:2426-2435. © 2019 SETAC.
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Affiliation(s)
- Grace E Schwartz
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Todd A Olsen
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Katherine A Muller
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Scott C Brooks
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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8
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Beau F, Bustamante P, Michaud B, Brischoux F. Environmental causes and reproductive correlates of mercury contamination in European pond turtles (Emys orbicularis). ENVIRONMENTAL RESEARCH 2019; 172:338-344. [PMID: 30825684 DOI: 10.1016/j.envres.2019.01.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/18/2019] [Accepted: 01/26/2019] [Indexed: 06/09/2023]
Abstract
Assessing Hg contamination in aquatic ecosystems is difficult because wetlands are part of large and complex networks, and potential sources of Hg contamination are highly diverse. To investigate environmental determinants of Hg contamination, we studied one of the largest continental French wetlands structured as a dense network of artificial ponds. Such context allows to investigate the influence of pond characteristics on Hg contamination in an area relatively disconnected from direct sources of pollution. We relied on a bioindicator organism, the European pond turtle (Emys orbicularis) to assess Hg contamination in a relatively large number of sites (N > 255 turtles from 15 ponds sampled in 2016 and 2017). Non-invasive sampling in the claws of turtles show that Hg concentrations were not related to their sex or size, but we found an effect of age (1.62 ± 0.20 in juveniles and 2.21 ± 0.06 µg g-1 dw in adults), suggesting that turtles do bioaccumulate Hg through their life. Turtle Hg was different between ponds, and we found that pond age and pond usage (draining events linked to pond maintenance) were the main environmental determinants of Hg concentrations in turtles. Finally, and more importantly, our dataset allowed us to highlight potential negative effect of Hg concentrations on the proportion of reproductive females, suggesting an influence of Hg on reproductive mechanisms in this species. This result indicates that Hg contamination, even in absence of direct and strong sources of pollution, may have a critical impact on reproduction and thus the persistence of a long-lived vertebrate.
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Affiliation(s)
- Frédéric Beau
- Centre d'Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-Université de La Rochelle, 79360 Villiers en Bois, France; Réserve Naturelle Nationale de Chérine, Maison de la Nature et de la Réserve, 36290 Saint-Michel-en-Brenne, France.
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-Université de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle, France
| | - Bruno Michaud
- Centre d'Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-Université de La Rochelle, 79360 Villiers en Bois, France
| | - François Brischoux
- Centre d'Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-Université de La Rochelle, 79360 Villiers en Bois, France
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9
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Mangal V, Stenzler BR, Poulain AJ, Guéguen C. Aerobic and Anaerobic Bacterial Mercury Uptake is Driven by Algal Organic Matter Composition and Molecular Weight. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:157-165. [PMID: 30516365 DOI: 10.1021/acs.est.8b04909] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The biological mobilization of mercury (Hg) into microbes capable of Hg methylation is one of the limiting steps in the formation of the neurotoxin methylmercury (MeHg). Although algal dissolved organic matter (DOM) has been associated with increased MeHg production, the relationship between bacterial Hg uptake and algal DOM remains unexplored. In this study, we aimed to address how the quantity and quality of DOM, freshly harvested from several algae, affected the bacterial uptake of Hg with the use of a biosensor capable of functioning both aerobically and anaerobically. We combined biosensor measurements with high-resolution mass spectrometry and field-flow fractionation to elucidate how DOM composition and molecular weight influenced microbial Hg uptake. We showed that freshly harvested DOM from Chlorophyte and Euglena mutabilis strongly inhibited aerobic and anaerobic Hg uptake, whereas DOM harvested from Euglena gracilis did not exhibit this same pronounced effect. Once fractionated, we found that amino acids and polyamines, most abundant in Euglena gracilis DOM, were positively correlated to increase Hg uptake, suggesting that these molecules are potentially underappreciated ligands affecting Hg bioavailability. As water quality is affected by eutrophication, algal community assemblages will change, leading to variations in the nature of autochthonous DOM released in aquatic systems. Our results highlight that variations in the emergent properties of DOM originating from varying algal species can have a profound effect on bacterial Hg uptake and thus methylation.
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Affiliation(s)
- Vaughn Mangal
- Environmental and Life Sciences Graduate program , Trent University , 1600 West Bank Drive Peterborough ON Canada , K9J 7B8
| | - Benjamin R Stenzler
- Biology Department , University of Ottawa , 30 Marie Curie , Ottawa ON Canada , K1N 6N5
| | - Alexandre J Poulain
- Biology Department , University of Ottawa , 30 Marie Curie , Ottawa ON Canada , K1N 6N5
| | - Celine Guéguen
- Chemistry Department , Trent University , 1600 West Bank Drive Peterborough ON Canada , K9J 7B8
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10
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Abstract
Mercury (Hg) is a global pollutant emitted primarily as gaseous Hg0 that is deposited in aquatic and terrestrial ecosystems following its oxidation to HgII. From that point, microbes play a key role in determining Hg’s fate in the environment by participating in sequestration, oxidation, reduction, and methylation reactions. A wide diversity of chemotrophic and phototrophic microbes occupying oxic and anoxic habitats are known to participate directly in Hg cycling. Over the last few years, new findings have come to light that have greatly improved our mechanistic understanding of microbe-mediated Hg cycling pathways in the environment. In this review, we summarize recent advances in microbially mediated Hg cycling and take the opportunity to compare the relatively well-studied chemotrophic pathways to poorly understood phototrophic pathways. We present how the use of genomic and analytical tools can be used to understand Hg transformations and the physiological context of recently discovered cometabolic Hg transformations supported in anaerobes and phototrophs. Finally, we propose a conceptual framework that emphasizes the role that phototrophs play in environmental Hg redox cycling and the importance of better characterizing such pathways in the face of the environmental changes currently underway.
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Affiliation(s)
- Daniel S. Grégoire
- Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Alexandre J. Poulain
- Biology Department, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
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11
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Graham EB, Gabor RS, Schooler S, McKnight DM, Nemergut DR, Knelman JE. Oligotrophic wetland sediments susceptible to shifts in microbiomes and mercury cycling with dissolved organic matter addition. PeerJ 2018; 6:e4575. [PMID: 29632744 PMCID: PMC5888151 DOI: 10.7717/peerj.4575] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/15/2018] [Indexed: 12/26/2022] Open
Abstract
Recent advances have allowed for greater investigation into microbial regulation of mercury toxicity in the environment. In wetlands in particular, dissolved organic matter (DOM) may influence methylmercury (MeHg) production both through chemical interactions and through substrate effects on microbiomes. We conducted microcosm experiments in two disparate wetland environments (oligotrophic unvegetated and high-C vegetated sediments) to examine the impacts of plant leachate and inorganic mercury loadings (20 mg/L HgCl2) on microbiomes and MeHg production in the St. Louis River Estuary. Our research reveals the greater relative capacity for mercury methylation in vegetated over unvegetated sediments. Further, our work shows how mercury cycling in oligotrophic unvegetated sediments may be susceptible to DOM inputs in the St. Louis River Estuary: unvegetated microcosms receiving leachate produced substantially more MeHg than unamended microcosms. We also demonstrate (1) changes in microbiome structure towards Clostridia, (2) metagenomic shifts toward fermentation, and (3) degradation of complex DOM; all of which coincide with elevated net MeHg production in unvegetated microcosms receiving leachate. Together, our work shows the influence of wetland vegetation in controlling MeHg production in the Great Lakes region and provides evidence that this may be due to both enhanced microbial activity as well as differences in microbiome composition.
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Affiliation(s)
- Emily B Graham
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States of America
| | - Rachel S Gabor
- School of Environment and Natural Resources, Ohio State University, Columbus, OH, United States of America
| | - Shon Schooler
- Lake Superior National Estuarine Research Reserve, Superior, WI, United States of America
| | - Diane M McKnight
- Institute for Arctic and Alpine Research, University of Colorado at Boulder, Boulder, CO, United States of America.,Civil Engineering Department, University of Colorado at Boulder, Boulder, CO, United States of America.,Environmental Studies Program, University of Colorado at Boulder, Boulder, CO, United States of America
| | - Diana R Nemergut
- Institute for Arctic and Alpine Research, University of Colorado at Boulder, Boulder, CO, United States of America.,Biology Department, Duke University, Durham, NC, United States of America
| | - Joseph E Knelman
- Institute for Arctic and Alpine Research, University of Colorado at Boulder, Boulder, CO, United States of America
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12
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Ranchou-Peyruse M, Goñi-Urriza M, Guignard M, Goas M, Ranchou-Peyruse A, Guyoneaud R. Pseudodesulfovibrio hydrargyri sp. nov., a mercury-methylating bacterium isolated from a brackish sediment. Int J Syst Evol Microbiol 2018. [PMID: 29533171 DOI: 10.1099/ijsem.0.002173] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The strain BerOc1T was isolated from brackish sediments contaminated with hydrocarbons and heavy metals. This strain has been used as a model strain of sulfate-reducer to study the biomethylation of mercury. The cells are vibrio-shaped, motile and not sporulated. Phylogeny and physiological traits placed this strain within the genus Pseudodesulfovibrio. Optimal growth was obtained at 30 °C, 1.5 % NaCl and pH 6.0-7.4. The estimated G+C content of the genomic DNA was 62.6 mol%. BerOc1T used lactate, pyruvate, fumarate, ethanol and hydrogen. Terminal electron acceptors used were sulfate, sulfite, thiosulfate and DMSO. Only pyruvate could be used without a terminal electron acceptor. The major fatty acids were C18 : 0, anteiso-C15 : 0, C16 : 0 and C18 : 1ω7. The name Pseudodesulfovibrio hydrargyri sp. nov. is proposed for the type strain BerOc1T (DSM 10384T=JCM 31820T).
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Affiliation(s)
- Magali Ranchou-Peyruse
- Université de Pau et des Pays de l'Adour, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - MIRA, UMR 5254, 64000, Pau, France
| | - Marisol Goñi-Urriza
- Université de Pau et des Pays de l'Adour, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - MIRA, UMR 5254, 64000, Pau, France
| | - Marion Guignard
- Université de Pau et des Pays de l'Adour, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - MIRA, UMR 5254, 64000, Pau, France
| | - Marjorie Goas
- Université de Pau et des Pays de l'Adour, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - MIRA, UMR 5254, 64000, Pau, France
| | - Anthony Ranchou-Peyruse
- Université de Pau et des Pays de l'Adour, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - MIRA, UMR 5254, 64000, Pau, France
| | - Rémy Guyoneaud
- Université de Pau et des Pays de l'Adour, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux - MIRA, UMR 5254, 64000, Pau, France
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