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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; 58:13795-13807. [PMID: 39046290 PMCID: PMC11308531 DOI: 10.1021/acs.est.4c00663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 07/02/2024] [Accepted: 07/02/2024] [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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Gillieatt BF, Coleman NV. Unravelling the mechanisms of antibiotic and heavy metal resistance co-selection in environmental bacteria. FEMS Microbiol Rev 2024; 48:fuae017. [PMID: 38897736 PMCID: PMC11253441 DOI: 10.1093/femsre/fuae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 06/09/2024] [Accepted: 06/18/2024] [Indexed: 06/21/2024] Open
Abstract
The co-selective pressure of heavy metals is a contributor to the dissemination and persistence of antibiotic resistance genes in environmental reservoirs. The overlapping range of antibiotic and metal contamination and similarities in their resistance mechanisms point to an intertwined evolutionary history. Metal resistance genes are known to be genetically linked to antibiotic resistance genes, with plasmids, transposons, and integrons involved in the assembly and horizontal transfer of the resistance elements. Models of co-selection between metals and antibiotics have been proposed, however, the molecular aspects of these phenomena are in many cases not defined or quantified and the importance of specific metals, environments, bacterial taxa, mobile genetic elements, and other abiotic or biotic conditions are not clear. Co-resistance is often suggested as a dominant mechanism, but interpretations are beset with correlational bias. Proof of principle examples of cross-resistance and co-regulation has been described but more in-depth characterizations are needed, using methodologies that confirm the functional expression of resistance genes and that connect genes with specific bacterial hosts. Here, we comprehensively evaluate the recent evidence for different models of co-selection from pure culture and metagenomic studies in environmental contexts and we highlight outstanding questions.
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Affiliation(s)
- Brodie F Gillieatt
- School of Life and Environmental Sciences, The University of Sydney, F22 - LEES Building, NSW 2006, Australia
| | - Nicholas V Coleman
- School of Natural Sciences, and ARC Centre of Excellence in Synthetic Biology, Macquarie University, 6 Wally’s Walk, Macquarie Park, NSW 2109, Australia
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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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4
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Zhang R, Aris-Brosou S, Storck V, Liu J, Abdelhafiz MA, Feng X, Meng B, Poulain AJ. Mining-impacted rice paddies select for Archaeal methylators and reveal a putative (Archaeal) regulator of mercury methylation. ISME COMMUNICATIONS 2023; 3:74. [PMID: 37454192 PMCID: PMC10349881 DOI: 10.1038/s43705-023-00277-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023]
Abstract
Methylmercury (MeHg) is a microbially produced neurotoxin derived from inorganic mercury (Hg), which accumulation in rice represents a major health concern to humans. However, the microbial control of MeHg dynamics in the environment remains elusive. Here, leveraging three rice paddy fields with distinct concentrations of Hg (Total Hg (THg): 0.21-513 mg kg-1 dry wt. soil; MeHg: 1.21-6.82 ng g-1 dry wt. soil), we resorted to metagenomics to determine the microbial determinants involved in MeHg production under contrasted contamination settings. We show that Hg methylating Archaea, along with methane-cycling genes, were enriched in severely contaminated paddy soils. Metagenome-resolved Genomes of novel putative Hg methylators belonging to Nitrospinota (UBA7883), with poorly resolved taxonomy despite high completeness, showed evidence of facultative anaerobic metabolism and adaptations to fluctuating redox potential. Furthermore, we found evidence of environmental filtering effects that influenced the phylogenies of not only hgcA genes under different THg concentrations, but also of two housekeeping genes, rpoB and glnA, highlighting the need for further experimental validation of whether THg drives the evolution of hgcAB. Finally, assessment of the genomic environment surrounding hgcAB suggests that this gene pair may be regulated by an archaeal toxin-antitoxin (TA) system, instead of the more frequently found arsR-like genes in bacterial methylators. This suggests the presence of distinct hgcAB regulation systems in bacteria and archaea. Our results support the emerging role of Archaea in MeHg cycling under mining-impacted environments and shed light on the differential control of the expression of genes involved in MeHg formation between Archaea and Bacteria.
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Affiliation(s)
- Rui Zhang
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Stéphane Aris-Brosou
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Veronika Storck
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, H3C 3A7, Canada
| | - Jiang Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Mahmoud A Abdelhafiz
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xinbin Feng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Bo Meng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
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Sun J, Su H, Zhang W, Luo X, Li R, Liu M. Comparative genomics revealed that Vibrio furnissii and Vibrio fluvialis have mutations in genes related to T6SS1 and T6SS2. Arch Microbiol 2023; 205:207. [PMID: 37101014 DOI: 10.1007/s00203-023-03557-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023]
Abstract
The type VI secretion system (T6SS) is important for interbacterial competition and virulence in Vibrio species. It is generally agreed that T6SS provides a fitness advantage to Vibrios. Some Vibrio species possess one, while others possess two T6SSs. Even within the same Vibrio species, different strains can harbor a variable number of T6SSs. Such is the case in V. fluvialis, an opportunistic human pathogen, that some V. fluvialis strains do not harbor T6SS1. This study found that Amphritea, Marinomonas, Marinobacterium, Vibrio, Photobacterium, and Oceanospirillum species have genes encoding V. fluvialis T6SS1 homologs. The cladogram of T6SS1 genes suggested that these genes appeared to be horizontally acquired by V. fluvialis, V. furnissii, and some other Vibrio species, when compared with the species tree. Codon insertions, codon deletions, nonsense mutations, and the insertion sequence are found in many genes, such as clpV1, tssL1, and tssF1, which encode structure components of T6SS1 in V. furnissii and V. fluvialis. Codon deletion events are more common than codon insertion, insertion sequence disruption, and nonsense mutation events in genes that encode components of T6SS1. Similarly, codon insertions and codon deletions are found in genes relevant to T6SS2, including tssM2, vgrG2 and vasH, in V. furnissii and V. fluvialis. These mutations are likely to disable the functions of T6SSs. Our findings indicate that T6SS may have a fitness disadvantage in V. furnissii and V. fluvialis, and the loss of function in T6SS may help these Vibrio species to survive under certain conditions.
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Affiliation(s)
- Jiakai Sun
- College of Oceanography, Hohai University, Nanjing, China
| | - Haochen Su
- College of Oceanography, Hohai University, Nanjing, China
| | - Wenhui Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - Xuesong Luo
- State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan, China
| | - Ruichao Li
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu Province, China.
| | - Ming Liu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, 518055, Guangdong Province, P. R. China.
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Lv Z, Xu M, Liu Y, Rønn R, Rensing C, Liu S, Gao S, Liao H, Liu YR, Chen W, Zhu YG, Huang Q, Hao X. Phagotrophic Protists Modulate Copper Resistance of the Bacterial Community in Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3590-3601. [PMID: 36811608 DOI: 10.1021/acs.est.2c07136] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Protist predation is a crucial biotic driver modulating bacterial populations and functional traits. Previous studies using pure cultures have demonstrated that bacteria with copper (Cu) resistance exhibited fitness advantages over Cu-sensitive bacteria under the pressure of protist predation. However, the impact of diverse natural communities of protist grazers on bacterial Cu resistance in natural environments remains unknown. Here, we characterized the communities of phagotrophic protists in long-term Cu-contaminated soils and deciphered their potential ecological impacts on bacterial Cu resistance. Long-term field Cu pollution increased the relative abundances of most of the phagotrophic lineages in Cercozoa and Amoebozoa but reduced the relative abundance of Ciliophora. After accounting for soil properties and Cu pollution, phagotrophs were consistently identified as the most important predictor of the Cu-resistant (CuR) bacterial community. Phagotrophs positively contributed to the abundance of a Cu resistance gene (copA) through influencing the cumulative relative abundance of Cu-resistant and -sensitive ecological clusters. Microcosm experiments further confirmed the promotion effect of protist predation on bacterial Cu resistance. Our results indicate that the selection by protist predation can have a strong impact on the CuR bacterial community, which broadens our understanding of the ecological function of soil phagotrophic protists.
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Affiliation(s)
- Zhenguang Lv
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Min Xu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Ying Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Regin Rønn
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Christopher Rensing
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Song Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shenghan Gao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Hao Liao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu-Rong Liu
- State 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
| | - Wenli Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Qiaoyun Huang
- State 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
| | - Xiuli Hao
- State 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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Serrana JM, Watanabe K. Sediment-associated microbial community profiling: sample pre-processing through sequential membrane filtration for 16S rRNA amplicon sequencing. BMC Microbiol 2022; 22:33. [PMID: 35057747 PMCID: PMC8772107 DOI: 10.1186/s12866-022-02441-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 01/10/2022] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Sequential membrane filtration as a pre-processing step for capturing sediment-associated microorganisms could provide good quality and integrity DNA that can be preserved and kept at ambient temperatures before community profiling through culture-independent molecular techniques. However, the effects of sample pre-processing via filtration on DNA-based profiling of sediment-associated microbial community diversity and composition are poorly understood. Specifically, the influences of pre-processing on the quality and quantity of extracted DNA, high-throughput DNA sequencing reads, and detected microbial taxa need further evaluation. RESULTS We assessed the impact of pre-processing freshwater sediment samples by sequential membrane filtration (from 10, 5 to 0.22 μm pore size) for 16S rRNA-based community profiling of sediment-associated microorganisms. Specifically, we examined if there would be method-driven differences between non- and pre-processed sediment samples regarding the quality and quantity of extracted DNA, PCR amplicon, resulting high-throughput sequencing reads, microbial diversity, and community composition. We found no significant difference in the qualities and quantities of extracted DNA and PCR amplicons, and the read abundance after bioinformatics processing (i.e., denoising and chimeric-read filtering steps) between the two methods. Although the non- and pre-processed sediment samples had more unique than shared amplicon sequence variants (ASVs), we report that their shared ASVs accounted for 74% of both methods' absolute read abundance. More so, at the genus level, the final collection filter identified most of the genera (95% of the reads) captured from the non-processed samples, with a total of 51 false-negative (2%) and 59 false-positive genera (3%). We demonstrate that while there were differences in shared and unique taxa, both methods revealed comparable microbial diversity and community composition. CONCLUSIONS Our observations highlight the feasibility of pre-processing sediment samples for community analysis and the need to further assess sampling strategies to help conceptualize appropriate study designs for sediment-associated microbial community profiling.
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Affiliation(s)
- Joeselle M Serrana
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 3, Matsuyama, Ehime, 790-8577, Japan
| | - Kozo Watanabe
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 3, Matsuyama, Ehime, 790-8577, Japan.
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Bowman KL, Lamborg CH, Agather AM, Hammerschmidt CR. The role of plastic debris in the biogeochemical cycle of mercury in Lake Erie and San Francisco Bay. MARINE POLLUTION BULLETIN 2021; 171:112768. [PMID: 34343756 DOI: 10.1016/j.marpolbul.2021.112768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
The accumulation of plastic debris that concentrates hydrophobic compounds and microbial communities creates the potential for altered aquatic biogeochemical cycles. This study investigated the role of plastic debris in the biogeochemical cycling of mercury in surface waters of the San Francisco Bay, Sacramento River, Lake Erie, and in coastal seawater. Total mercury and monomethylmercury were measured on plastic debris from all study sites. Plastic-bound microbial communities from Lake Erie and San Francisco Bay contained several lineages of known mercury methylating microbes, however the hgcAB gene cluster was not detected using polymerase chain reaction. These plastic-bound microbial communities also contained species that possess the mer operon, and merA genes were detected using polymerase chain reaction. In coastal seawater incubations, rapid mercury methylation percentages were greater in the presence of microplastics and demethylation percentages decreased as monomethylmercury additions adsorbed to microplastics. These findings suggest that plastic pollution has the potential to alter the biogeochemical cycling of mercury in aquatic ecosystems.
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Affiliation(s)
- Katlin L Bowman
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, United States of America; Moss Landing Marine Laboratories, Moss Landing, CA 95039, United States of America.
| | - Carl H Lamborg
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, United States of America
| | - Alison M Agather
- Department of Earth & Environmental Sciences, Wright State University, Dayton, OH 45435, United States of America; Cherokee Nation Strategic Programs, Arlington, VA 22202, United States of America
| | - Chad R Hammerschmidt
- Department of Earth & Environmental Sciences, Wright State University, Dayton, OH 45435, United States of America
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Mejbel HS, Dodsworth W, Baud A, Gregory-Eaves I, Pick FR. Comparing Quantitative Methods for Analyzing Sediment DNA Records of Cyanobacteria in Experimental and Reference Lakes. Front Microbiol 2021; 12:669910. [PMID: 34220754 PMCID: PMC8250803 DOI: 10.3389/fmicb.2021.669910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/19/2021] [Indexed: 11/25/2022] Open
Abstract
Sediment DNA (sedDNA) analyses are rapidly emerging as powerful tools for the reconstruction of environmental and evolutionary change. While there are an increasing number of studies using molecular genetic approaches to track changes over time, few studies have compared the coherence between quantitative polymerase chain reaction (PCR) methods and metabarcoding techniques. Primer specificity, bioinformatic analyses, and PCR inhibitors in sediments could affect the quantitative data obtained from these approaches. We compared the performance of droplet digital polymerase chain reaction (ddPCR) and high-throughput sequencing (HTS) for the quantification of target genes of cyanobacteria in lake sediments and tested whether the two techniques similarly reveal expected patterns through time. Absolute concentrations of cyanobacterial 16S rRNA genes were compared between ddPCR and HTS using dated sediment cores collected from two experimental (Lake 227, fertilized since 1969 and Lake 223, acidified from 1976 to 1983) and two reference lakes (Lakes 224 and 442) in the Experimental Lakes Area (ELA), Canada. Relative abundances of Microcystis 16S rRNA (MICR) genes were also compared between the two methods. Moderate to strong positive correlations were found between the molecular approaches among all four cores but results from ddPCR were more consistent with the known history of lake manipulations. A 100-fold increase in ddPCR estimates of cyanobacterial gene abundance beginning in ~1968 occurred in Lake 227, in keeping with experimental addition of nutrients and increase in planktonic cyanobacteria. In contrast, no significant rise in cyanobacterial abundance associated with lake fertilization was observed with HTS. Relative abundances of Microcystis between the two techniques showed moderate to strong levels of coherence in top intervals of the sediment cores. Both ddPCR and HTS approaches are suitable for sedDNA analysis, but studies aiming to quantify absolute abundances from complex environments should consider using ddPCR due to its high tolerance to PCR inhibitors.
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Affiliation(s)
- Hebah S Mejbel
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - William Dodsworth
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Alexandre Baud
- Department of Biology, McGill University, Montréal, QC, Canada.,Groupe de Recherche Interuniversitaire en Limnologie, Montréal, QC, Canada
| | - Irene Gregory-Eaves
- Department of Biology, McGill University, Montréal, QC, Canada.,Groupe de Recherche Interuniversitaire en Limnologie, Montréal, QC, Canada
| | - Frances R Pick
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada
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10
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Pearman JK, Thomson-Laing G, Howarth JD, Vandergoes MJ, Thompson L, Rees A, Wood SA. Investigating variability in microbial community composition in replicate environmental DNA samples down lake sediment cores. PLoS One 2021; 16:e0250783. [PMID: 33939728 PMCID: PMC8092796 DOI: 10.1371/journal.pone.0250783] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 04/14/2021] [Indexed: 01/04/2023] Open
Abstract
Lake sediments are natural archives that accumulate information on biological communities and their surrounding catchments. Paleolimnology has traditionally focussed on identifying fossilized organisms to reconstruct past environments. In the last decade, the application of molecular methodologies has increased in paleolimnological studies, but further research investigating factors such as sample heterogeneity and DNA degradation are required. In the present study we investigated bacterial community heterogeneity (16S rRNA metabarcoding) within depth slices (1-cm width). Sediment cores were collected from three lakes with differing sediment compositions. Samples were collected from a variety of depths which represent a period of time of approximately 1,200 years. Triplicate samples were collected from each depth slice and bacterial 16S rRNA metabarcoding was undertaken on each sample. Accumulation curves demonstrated that except for the deepest (oldest) slices, the combination of three replicate samples were insufficient to characterise the entire bacterial diversity. However, shared Amplicon Sequence Variants (ASVs) accounted for the majority of the reads in each depth slice (max. shared proportional read abundance 96%, 86%, 65% in the three lakes). Replicates within a depth slice generally clustered together in the Non-metric multidimensional scaling analysis. There was high community dissimilarity in older sediment in one of the cores, which was likely due to the laminae in the sediment core not being horizontal. Given that most paleolimnology studies explore broad scale shifts in community structure rather than seeking to identify rare species, this study demonstrates that a single sample is adequate to characterise shifts in dominant bacterial ASVs.
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Affiliation(s)
- John K. Pearman
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
| | | | | | | | - Lucy Thompson
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
| | - Andrew Rees
- Victoria University of Wellington, Wellington, New Zealand
| | - Susanna A. Wood
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
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11
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Misson B, Garnier C, Poulain AJ. Limited influence of marine sediment lyophilization on prokaryotic community structure assessed via amplicon sequencing: an example from environmentally contrasted sediment layers in Toulon harbor (France). PeerJ 2021; 9:e11075. [PMID: 33868808 PMCID: PMC8035903 DOI: 10.7717/peerj.11075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 02/17/2021] [Indexed: 11/20/2022] Open
Abstract
Sediment lyophilization is a common process that allows for long-term conservation and sharing of marine sediments for multiple downstream analyses. Although it is often used for geochemical studies, the effects of lyophilization on prokaryotic taxonomic diversity assessment remained to be assessed. Here, we tested the effect of lyophilization on microbial diversity assessment using three sediment layers corresponding to various sediment ages and chemical contamination levels sampled from a marine Mediterranean harbor. Duplicate DNA samples were extracted from wet frozen or lyophilized sediments, and 16S rRNA gene amplicon sequence variants were analyzed. We detected changes in community structure over depth linked to both dominant and less abundant taxa whether sediments were lyophilized or not. Data from both wet frozen and lyophilized sediments led us to conclude that historical chemical contamination of the sediment of Toulon Bay did not appear to be the main environmental variable shaping prokaryotic community structure on the vertical dimension, but that sediment diagenesis was. We conclude that sediment lyophilization is compatible with marine biogeochemical and ecotoxicological studies but that caution should be used when discussing small variations among samples.
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Affiliation(s)
- Benjamin Misson
- Université de Toulon, Aix Marseille University, CNRS, IRD, MIO, Toulon, France
| | - Cédric Garnier
- Université de Toulon, Aix Marseille University, CNRS, IRD, MIO, Toulon, France
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12
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Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations. QUATERNARY 2021. [DOI: 10.3390/quat4010006] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.
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13
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Hao X, Zhu J, Rensing C, Liu Y, Gao S, Chen W, Huang Q, Liu YR. Recent advances in exploring the heavy metal(loid) resistant microbiome. Comput Struct Biotechnol J 2020; 19:94-109. [PMID: 33425244 PMCID: PMC7771044 DOI: 10.1016/j.csbj.2020.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/18/2022] Open
Abstract
Heavy metal(loid)s exert selective pressure on microbial communities and evolution of metal resistance determinants. Despite increasing knowledge concerning the impact of metal pollution on microbial community and ecological function, it is still a challenge to identify a consistent pattern of microbial community composition along gradients of elevated metal(loid)s in natural environments. Further, our current knowledge of the microbial metal resistome at the community level has been lagging behind compared to the state-of-the-art genetic profiling of bacterial metal resistance mechanisms in a pure culture system. This review provides an overview of the core metal resistant microbiome, development of metal resistance strategies, and potential factors driving the diversity and distribution of metal resistance determinants in natural environments. The impacts of biotic factors regulating the bacterial metal resistome are highlighted. We finally discuss the advances in multiple technologies, research challenges, and future directions to better understand the interface of the environmental microbiome with the metal resistome. This review aims to highlight the diversity and wide distribution of heavy metal(loid)s and their corresponding resistance determinants, helping to better understand the resistance strategy at the community level.
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Affiliation(s)
- Xiuli Hao
- State 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
- Corresponding authors at: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jiaojiao Zhu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christopher Rensing
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Ying Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Shenghan Gao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenli Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- State 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
- State 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
- Corresponding authors at: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
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Garner RE, Gregory-Eaves I, Walsh DA. Sediment Metagenomes as Time Capsules of Lake Microbiomes. mSphere 2020; 5:e00512-20. [PMID: 33148818 PMCID: PMC7643826 DOI: 10.1128/msphere.00512-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/21/2020] [Indexed: 12/22/2022] Open
Abstract
The reconstruction of ecological time series from lake sediment archives can retrace the environmental impact of human activities. Molecular genetic approaches in paleolimnology have provided unprecedented access to DNA time series, which record evidence of the microbial ecologies that underlaid historical lake ecosystems. Such studies often rely on single-gene surveys, and consequently, the full diversity of preserved microorganisms remains unexplored. In this study, we probed the diversity archived in contemporary and preindustrial sediments by comparative shotgun metagenomic analysis of surface water and sediment samples from three eastern Canadian lakes. In a strategy that was aimed at disentangling historical DNA from the indigenous sediment background, microbial preservation signals were captured by mapping sequence similarities between sediment metagenome reads and reference surface water metagenome assemblies. We detected preserved Cyanobacteria, diverse bacterioplankton, microeukaryotes, and viruses in sediment metagenomes. Among the preserved microorganisms were important groups never before reported in paleolimnological reconstructions, including bacteriophages (Caudovirales) and ubiquitous freshwater Betaproteobacteria (Polynucleobacter and Limnohabitans). In contrast, ultramicroscopic Actinobacteria ("Candidatus Nanopelagicales") and Alphaproteobacteria (Pelagibacterales) were apparently not well preserved in sediment metagenomes even though they were numerically dominant in surface water metagenomes. Overall, our study explored a novel application of whole-metagenome shotgun sequencing for discovering the DNA remains of a broad diversity of microorganisms preserved in lake sediments. The recovery of diverse microbial time series supports the taxonomic expansion of microbiome reconstructions and the development of novel microbial paleoindicators.IMPORTANCE Lakes are critical freshwater resources under mounting pressure from climate change and other anthropogenic stressors. The reconstruction of ecological time series from sediment archives with paleolimnological techniques has been shown to be an effective means of understanding how humans are modifying lake ecosystems over extended timescales. In this study, we combined shotgun DNA sequencing with a novel comparative analysis of surface water and sediment metagenomes to expose the diversity of microorganisms preserved in lake sediments. The detection of DNA from a broad diversity of preserved microbes serves to more fully reconstruct historical microbiomes and describe preimpact lake conditions.
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Affiliation(s)
- Rebecca E Garner
- Department of Biology, Concordia University, Montreal, Quebec, Canada
- Groupe de Recherche Interuniversitaire en Limnologie, Montreal, Quebec, Canada
| | - Irene Gregory-Eaves
- Department of Biology, McGill University, Montreal, Quebec, Canada
- Groupe de Recherche Interuniversitaire en Limnologie, Montreal, Quebec, Canada
| | - David A Walsh
- Department of Biology, Concordia University, Montreal, Quebec, Canada
- Groupe de Recherche Interuniversitaire en Limnologie, Montreal, Quebec, Canada
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15
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Colby GA, Ruuskanen MO, St.Pierre KA, St.Louis VL, Poulain AJ, Aris-Brosou S. Warming Climate Is Reducing the Diversity of Dominant Microbes in the Largest High Arctic Lake. Front Microbiol 2020; 11:561194. [PMID: 33133035 PMCID: PMC7579425 DOI: 10.3389/fmicb.2020.561194] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/28/2020] [Indexed: 11/13/2022] Open
Abstract
Temperatures in the Arctic are expected to increase dramatically over the next century, and transform high latitude watersheds. However, little is known about how microbial communities and their underlying metabolic processes will be affected by these environmental changes in freshwater sedimentary systems. To address this knowledge gap, we analyzed sediments from Lake Hazen, NU Canada. Here, we exploit the spatial heterogeneity created by varying runoff regimes across the watershed of this uniquely large high-latitude lake to test how a transition from low to high runoff, used as one proxy for climate change, affects the community structure and functional potential of dominant microbes. Based on metagenomic analyses of lake sediments along these spatial gradients, we show that increasing runoff leads to a decrease in taxonomic and functional diversity of sediment microbes. Our findings are likely to apply to other, smaller, glacierized watersheds typical of polar or high latitude ecosystems; we can predict that such changes will have far reaching consequences on these ecosystems by affecting nutrient biogeochemical cycling, the direction and magnitude of which are yet to be determined.
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Affiliation(s)
- Graham A. Colby
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | | | - Kyra A. St.Pierre
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Vincent L. St.Louis
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | | | - Stéphane Aris-Brosou
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, ON, Canada
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16
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Swift evolutionary response of microbes to a rise in anthropogenic mercury in the Northern Hemisphere. ISME JOURNAL 2019; 14:788-800. [PMID: 31831837 PMCID: PMC7031220 DOI: 10.1038/s41396-019-0563-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 11/17/2019] [Indexed: 01/22/2023]
Abstract
Anthropogenic mercury remobilization has considerably increased since the Industrial Revolution in the late 1700s. The Minamata Convention on Mercury is a United Nations treaty (2017) aiming at curbing mercury emissions. Unfortunately, evaluating the effectiveness of such a global treaty is hampered by our inability to determine the lag in aquatic ecosystem responses to a change in atmospheric mercury deposition. Whereas past metal concentrations are obtained from core samples, there are currently no means of tracking historical metal bioavailability or toxicity. Here, we recovered DNA from nine dated sediment cores collected in Canada and Finland, and reconstructed the past demographics of microbes carrying genes coding for the mercuric reductase (MerA)—an enzyme involved in Hg detoxification—using Bayesian relaxed molecular clocks. We found that the evolutionary dynamics of merA exhibited a dramatic increase in effective population size starting from 1783.8 ± 3.9 CE, which coincides with both the Industrial Revolution, and with independent measurements of atmospheric Hg concentrations. We show that even low levels of anthropogenic mercury affected the evolutionary trajectory of microbes in the Northern Hemisphere, and that microbial DNA encoding for detoxification determinants stored in environmental archives can be used to track historical pollutant toxicity.
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17
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Lee CS, Fisher NS. Microbial generation of elemental mercury from dissolved methylmercury in seawater. LIMNOLOGY AND OCEANOGRAPHY 2019; 64:679-693. [PMID: 31105337 PMCID: PMC6519744 DOI: 10.1002/lno.11068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Elemental mercury (Hg0) formation from other mercury species in seawater results from photoreduction and microbial activity, leading to possible evasion from seawater to overlying air. Microbial conversion of monomethylmercury (MeHg) to Hg0 in seawater remains unquantified. A rapid radioassay method was developed using gamma-emitting 203Hg as a tracer to evaluate Hg0 production from Hg(II) and MeHg in the low pM range. Bacterioplankton assemblages in Atlantic surface seawater and Long Island Sound water were found to rapidly produce Hg0, with production rate constants being directly related to bacterial biomass and independent of dissolved Hg(II) and MeHg concentrations. About 32% of Hg(II) and 19% of MeHg were converted to Hg0 in 4 d in Atlantic surface seawater containing low bacterial biomass, and in Long Island Sound water with higher bacterial biomass, 54% of Hg(II) and 8% of MeHg were transformed to Hg0. Decreasing temperatures from 24°C to 4°C reduced Hg0 production rates cell-1 from Hg(II) 3.3 times as much as from a MeHg source. Because Hg0 production rates were linearly related to microbial biomass and temperature, and microbial mercuric reductase was detected in our field samples, we inferred that microbial metabolic activities and enzymatic reactions primarily govern Hg0 formation in subsurface waters where light penetration is diminished.
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18
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Shoji A, Elliott KH, Aris-Brosou S, Mizukawa H, Nakayama SMM, Ikenaka Y, Ishizuka M, Kuwae T, Watanabe K, Escoruela Gonzalez J, Watanuki Y. Biotransport of metallic trace elements from marine to terrestrial ecosystems by seabirds. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2019; 38:106-114. [PMID: 30284322 DOI: 10.1002/etc.4286] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/20/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
Physical systems, such as currents and winds, have traditionally been considered responsible for transporting contaminants. Although evidence is mounting that animals play a role in this process through their movements, we still know little about how such contaminant biotransport occurs and the extent of effects at deposition sites. In the present study, we address this question by studying how rhinoceros auklets (Cerorhinca monocerata), a seabird that occurs in immense colonies (∼300 000 pairs at our study site, Teuri Island), affect contaminant levels at their colony and at nearby sites. More specifically, we hypothesize that contaminants are transported and deposited by seabirds at their colony and that these contaminants are passed on locally to the terrestrial ecosystem. To test this hypothesis, we analyzed the concentration of 9 heavy metal and metalloids, as well as δ13 C and δ15 N stable isotopes, in bird tissues, plants, and soil, both within and outside of the colony. The results show that rhinoceros auklets transport marine-derived mercury (Hg), possibly from their wintering location, and deposit Hg via their feces at their breeding site, thereby contaminating plants and soils within the breeding colony. The present study confirms not only that animals can transport contaminants from marine to terrestrial ecosystems, potentially over unexpectedly long distances, but also that bird tissues contribute locally to plant contamination. Environ Toxicol Chem 2019;38:106-114. © 2018 SETAC.
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Affiliation(s)
- A Shoji
- Graduate School of Fisheries Sciences, Hokkaido University, Hokkaido, Japan
- Department of Zoology, Oxford University, Oxford, United Kingdom
| | - K H Elliott
- Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Quebec, Canada
| | - S Aris-Brosou
- Departments of Biology and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - H Mizukawa
- Department of Environmental Veterinary Sciences, Laboratory of Toxicology, Hokkaido University, Hokkaido, Japan
| | - S M M Nakayama
- Department of Environmental Veterinary Sciences, Laboratory of Toxicology, Hokkaido University, Hokkaido, Japan
| | - Y Ikenaka
- Department of Environmental Veterinary Sciences, Laboratory of Toxicology, Hokkaido University, Hokkaido, Japan
- Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - M Ishizuka
- Department of Environmental Veterinary Sciences, Laboratory of Toxicology, Hokkaido University, Hokkaido, Japan
| | - T Kuwae
- Coastal and Estuarine Environment Research Group, Port and Airport Research Institute, Yokosuka, Japan
| | - K Watanabe
- Coastal and Estuarine Environment Research Group, Port and Airport Research Institute, Yokosuka, Japan
| | - J Escoruela Gonzalez
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Barcelona, Spain
| | - Y Watanuki
- Graduate School of Fisheries Sciences, Hokkaido University, Hokkaido, Japan
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19
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Zhang J, Yang M, Zhong H, Liu M, Sui Q, Zheng L, Tong J, Wei Y. Deciphering the factors influencing the discrepant fate of antibiotic resistance genes in sludge and water phases during municipal wastewater treatment. BIORESOURCE TECHNOLOGY 2018; 265:310-319. [PMID: 29909361 DOI: 10.1016/j.biortech.2018.06.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 06/05/2018] [Accepted: 06/08/2018] [Indexed: 05/21/2023]
Abstract
The discrepant fate of antibiotic resistance genes (ARGs) in sludge and water phases was investigated in a municipal wastewater treatment plant, and a lab-scale A2O-MBR was operated to provide background value of ARGs. The influencing factors of ARGs including microbial community, co-selection from heavy metals, biomass and horizontal gene transfer were concerned. Results showed that iA2O (inversed A2O) showed better ARGs reduction, and longer SRT (sludge retention time) increased ARGs relative abundance while reduced the gene copies of ARGs in the effluent, but significantly increased the ARGs in sludge phase. Compared to background value, the most enriched ARG was tetX in water phase, while it was intI1 in sludge phase. There existed higher abundance of multi-resistant bacteria in sludge phase, and microbial community determined the fate of ARGs in both water and sludge phase, while the direct effects from horizontal gene transfer should not be overlooked especially in water phase.
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Affiliation(s)
- Junya Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Yang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China; Changsha University of Science and Technology, Changsha 4110114, China
| | - Hui Zhong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengmeng Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qianwen Sui
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Libing Zheng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Juan Tong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuansong Wei
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Pollution Control Technology, 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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20
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Ruuskanen MO, St Pierre KA, St Louis VL, Aris-Brosou S, Poulain AJ. Physicochemical Drivers of Microbial Community Structure in Sediments of Lake Hazen, Nunavut, Canada. Front Microbiol 2018; 9:1138. [PMID: 29922252 PMCID: PMC5996194 DOI: 10.3389/fmicb.2018.01138] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 05/14/2018] [Indexed: 11/13/2022] Open
Abstract
The Arctic is undergoing rapid environmental change, potentially affecting the physicochemical constraints of microbial communities that play a large role in both carbon and nutrient cycling in lacustrine environments. However, the microbial communities in such Arctic environments have seldom been studied, and the drivers of their composition are poorly characterized. To address these gaps, we surveyed the biologically active surface sediments in Lake Hazen, the largest lake by volume north of the Arctic Circle, and a small lake and shoreline pond in its watershed. High-throughput amplicon sequencing of the 16S rRNA gene uncovered a community dominated by Proteobacteria, Bacteroidetes, and Chloroflexi, similar to those found in other cold and oligotrophic lake sediments. We also show that the microbial community structure in this Arctic polar desert is shaped by pH and redox gradients. This study lays the groundwork for predicting how sediment microbial communities in the Arctic could respond as climate change proceeds to alter their physicochemical constraints.
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Affiliation(s)
| | - Kyra A St Pierre
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Vincent L St Louis
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Stéphane Aris-Brosou
- Department of Biology, University of Ottawa, Ottawa, ON, Canada.,Department of Mathematics and Statistics, University of Ottawa, Ottawa, ON, Canada
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21
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Bafana A, Khan F, Suguna K. Structural and functional characterization of mercuric reductase from Lysinibacillus sphaericus strain G1. Biometals 2017; 30:809-819. [PMID: 28894951 DOI: 10.1007/s10534-017-0050-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/04/2017] [Indexed: 11/25/2022]
Abstract
In response to the widespread presence of inorganic Hg in the environment, bacteria have evolved resistance systems with mercuric reductase (MerA) as the key enzyme. MerA enzymes have still not been well characterized from gram positive bacteria. Current study reports physico-chemical, kinetic and structural characterization of MerA from a multiple heavy metal resistant strain of Lysinibacillus sphaericus, and discusses its implications in bioremediation application. The enzyme was homodimeric with subunit molecular weight of about 60 kDa. The Km and Vmax were found to be 32 µM of HgCl2 and 18 units/mg respectively. The enzyme activity was enhanced by β-mercaptoethanol and NaCl up to concentrations of 500 µM and 100 mM respectively, followed by inhibition at higher concentrations. The enzyme showed maximum activity in the pH range of 7-7.5 and temperature range of 25-50 °C, with melting temperature of 67 °C. Cu2+ exhibited pronounced inhibition of the enzyme with mixed inhibition pattern. The enzyme contained FAD as the prosthetic group and used NADPH as the preferred electron donor, but it showed slight activity with NADH as well. Structural characterization was carried out by circular dichroism spectrophotometry and X-ray crystallography. X-ray confirmed the homodimeric structure of enzyme and gave an insight on the residues involved in catalytic binding. In conclusion, the investigated enzyme showed higher catalytic efficiency, temperature stability and salt tolerance as compared to MerA enzymes from other mesophiles. Therefore, it is proposed to be a promising candidate for Hg2+ bioremediation.
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Affiliation(s)
- Amit Bafana
- Environmental Impact and Sustainability Division, CSIR-NEERI (National Environmental Engineering Research Institute), Nagpur, 440020, India.
| | - Farha Khan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
| | - Kaza Suguna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
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Korosi JB, Thienpont JR, Smol JP, Blais JM. Paleo-ecotoxicology: What Can Lake Sediments Tell Us about Ecosystem Responses to Environmental Pollutants? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:9446-9457. [PMID: 28763202 DOI: 10.1021/acs.est.7b02375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The development of effective risk reduction strategies for aquatic pollutants requires a comprehensive understanding of toxic impacts on ecosystems. Classical toxicological studies are effective for characterizing pollutant impacts on biota in a controlled, simplified environment. Nonetheless, it is well-acknowledged that predictions based on the results of these studies must be tested over the long-term in a natural ecosystem setting to account for increased complexity and multiple stressors. Paleolimnology (the study of lake sediment cores to reconstruct environmental change) can address many key knowledge gaps. When used as part of a weight-of-evidence framework with more traditional approaches in ecotoxicology, it can facilitate rapid advances in our understanding of the chronic effects of pollutants on ecosystems in an environmentally realistic, multistressor context. Paleolimnology played a central role in the Acid Rain debates, as it was instrumental in demonstrating industrial emissions caused acidification of lakes and associated ecosystem-wide impacts. "Resurrection Ecology" (hatching dormant resting eggs deposited in the past) records evolutionary responses of populations to chronic pollutant exposure. With recent technological advances (e.g., geochemistry, genomic approaches), combined with an emerging paleo-ecotoxicological framework that leverages strengths across multiple disciplines, paleolimnology will continue to provide valuable insights into the most pressing questions in ecotoxicology.
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Affiliation(s)
- Jennifer B Korosi
- Department of Geography, York University , Toronto, Ontario Canada , M3J 1P3
| | - Joshua R Thienpont
- Department of Biology, University of Ottawa , Ottawa, Ontario Canada , K1N 6N5
| | - John P Smol
- Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen's University , Kingston, Ontario Canada , K7L 3N6
| | - Jules M Blais
- Department of Biology, University of Ottawa , Ottawa, Ontario Canada , K1N 6N5
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Cellular toxicity pathways of inorganic and methyl mercury in the green microalga Chlamydomonas reinhardtii. Sci Rep 2017; 7:8034. [PMID: 28808314 PMCID: PMC5556115 DOI: 10.1038/s41598-017-08515-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/16/2017] [Indexed: 11/19/2022] Open
Abstract
Contamination by mercury (Hg) is a worldwide concern because of Hg toxicity and biomagnification in aquatic food webs. Nevertheless, bioavailability and cellular toxicity pathways of inorganic (IHg) and methyl-Hg (MeHg) remain poorly understood. We analyzed the uptake, transcriptomic, and physiological responses in the microalga Chlamydomonas reinhardtii exposed to IHg or MeHg. Bioavailability of MeHg was up to 27× higher than for IHg. Genes involved in cell processes, energy metabolism and transport were dysregulated by both Hg species. Physiological analysis revealed an impact on photosynthesis and reduction–oxidation reaction metabolism. Nevertheless, MeHg dysregulated a larger number of genes and with a stronger fold-change than IHg at equivalent intracellular concentration. Analysis of the perturbations of the cell’s functions helped to derive a detailed mechanistic understanding of differences in cellular handling of IHg and MeHg resulting in MeHg having a stronger impact. This knowledge is central for the prediction of impact of toxicants on organisms.
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24
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Parducci L, Bennett KD, Ficetola GF, Alsos IG, Suyama Y, Wood JR, Pedersen MW. Ancient plant DNA in lake sediments. THE NEW PHYTOLOGIST 2017; 214:924-942. [PMID: 28370025 DOI: 10.1111/nph.14470] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 12/07/2016] [Indexed: 05/14/2023]
Abstract
Contents 924 I. 925 II. 925 III. 927 IV. 929 V. 930 VI. 930 VII. 931 VIII. 933 IX. 935 X. 936 XI. 938 938 References 938 SUMMARY: Recent advances in sequencing technologies now permit the analyses of plant DNA from fossil samples (ancient plant DNA, plant aDNA), and thus enable the molecular reconstruction of palaeofloras. Hitherto, ancient frozen soils have proved excellent in preserving DNA molecules, and have thus been the most commonly used source of plant aDNA. However, DNA from soil mainly represents taxa growing a few metres from the sampling point. Lakes have larger catchment areas and recent studies have suggested that plant aDNA from lake sediments is a more powerful tool for palaeofloristic reconstruction. Furthermore, lakes can be found globally in nearly all environments, and are therefore not limited to perennially frozen areas. Here, we review the latest approaches and methods for the study of plant aDNA from lake sediments and discuss the progress made up to the present. We argue that aDNA analyses add new and additional perspectives for the study of ancient plant populations and, in time, will provide higher taxonomic resolution and more precise estimation of abundance. Despite this, key questions and challenges remain for such plant aDNA studies. Finally, we provide guidelines on technical issues, including lake selection, and we suggest directions for future research on plant aDNA studies in lake sediments.
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Affiliation(s)
- Laura Parducci
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, Uppsala, 75236, Sweden
| | - Keith D Bennett
- Department of Geography & Sustainable Development, School of Geography & Geosciences, University of St Andrews, St Andrews, Fife, KY16 9AL, UK
- Marine Laboratory, Queen's University Belfast, Portaferry, BT22 1LS, UK
| | - Gentile Francesco Ficetola
- CNRS, Université Grenoble-Alpes, Laboratoire d'Ecologie Alpine (LECA), Grenoble, F-38000, France
- Department of Biosciences, Università degli Studi di Milano, Milan, 20133, Italy
| | - Inger Greve Alsos
- Tromsø Museum, UiT - The Arctic University of Norway, Tromsø, NO-9037, Norway
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711, Japan
| | - Jamie R Wood
- Long-term Ecology Lab, Landcare Research, PO Box 69040, Lincoln Canterbury, 7640, New Zealand
| | - Mikkel Winther Pedersen
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, 1350, Denmark
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25
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Abstract
Antibiotic resistance is recognised as a major global threat to public health by the World Health Organization. Currently, several hundred thousand deaths yearly can be attributed to infections with antibiotic-resistant bacteria. The major driver for the development of antibiotic resistance is considered to be the use, misuse and overuse of antibiotics in humans and animals. Nonantibiotic compounds, such as antibacterial biocides and metals, may also contribute to the promotion of antibiotic resistance through co-selection. This may occur when resistance genes to both antibiotics and metals/biocides are co-located together in the same cell (co-resistance), or a single resistance mechanism (e.g. an efflux pump) confers resistance to both antibiotics and biocides/metals (cross-resistance), leading to co-selection of bacterial strains, or mobile genetic elements that they carry. Here, we review antimicrobial metal resistance in the context of the antibiotic resistance problem, discuss co-selection, and highlight critical knowledge gaps in our understanding.
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26
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Gillings MR. Lateral gene transfer, bacterial genome evolution, and the Anthropocene. Ann N Y Acad Sci 2016; 1389:20-36. [DOI: 10.1111/nyas.13213] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/20/2016] [Accepted: 07/28/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Michael R. Gillings
- Genes to Geoscience Research Centre, Department of Biological Sciences Macquarie University Sydney New South Wales Australia
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27
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Lloyd NA, Janssen SE, Reinfelder JR, Barkay T. Co-selection of Mercury and Multiple Antibiotic Resistances in Bacteria Exposed to Mercury in the Fundulus heteroclitus Gut Microbiome. Curr Microbiol 2016; 73:834-842. [DOI: 10.1007/s00284-016-1133-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
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Gillings MR, Paulsen IT, Tetu SG. Ecology and Evolution of the Human Microbiota: Fire, Farming and Antibiotics. Genes (Basel) 2015; 6:841-57. [PMID: 26371047 PMCID: PMC4584332 DOI: 10.3390/genes6030841] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 08/26/2015] [Accepted: 08/31/2015] [Indexed: 01/15/2023] Open
Abstract
Human activities significantly affect all ecosystems on the planet, including the assemblages that comprise our own microbiota. Over the last five million years, various evolutionary and ecological drivers have altered the composition of the human microbiota, including the use of fire, the invention of agriculture, and the increasing availability of processed foods after the Industrial Revolution. However, no factor has had a faster or more direct effect than antimicrobial agents. Biocides, disinfectants and antibiotics select for individual cells that carry resistance genes, immediately reducing both overall microbial diversity and within-species genetic diversity. Treated individuals may never recover their original diversity, and repeated treatments lead to a series of genetic bottlenecks. The sequential introduction of diverse antimicrobial agents has selected for increasingly complex DNA elements that carry multiple resistance genes, and has fostered their spread through the human microbiota. Practices that interfere with microbial colonization, such as sanitation, Caesarian births and bottle-feeding, exacerbate the effects of antimicrobials, generating species-poor and less resilient microbial assemblages in the developed world. More and more evidence is accumulating that these perturbations to our internal ecosystems lie at the heart of many diseases whose frequency has shown a dramatic increase over the last half century.
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Affiliation(s)
- Michael R Gillings
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
| | - Ian T Paulsen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia.
| | - Sasha G Tetu
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia.
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