1
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Xiong X, Li Y, Zhang C. Enhanced phosphorus removal from anoxic water using oxygen-carrying iron-rich biochar: Combined roles of adsorption and keystone taxa. WATER RESEARCH 2024; 266:122433. [PMID: 39276477 DOI: 10.1016/j.watres.2024.122433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Revised: 09/01/2024] [Accepted: 09/10/2024] [Indexed: 09/17/2024]
Abstract
Anthropogenic enrichment of phosphorus (P) in water environment can cause eutrophication, harmful algal blooms, and water quality deterioration. Adsorbents are often used for the removal and recovery of P from water, however, P is highly susceptible to re-release in anoxic benthic environments. As a response, this study prepared oxygen-carrying iron-rich biochar (O-Fe-BC) as an effective oxygen micro-nanobubble carrier (Q = 8.7024 cm³/g STP at 1.5 MPa) and P adsorbent (qm = 16.7097 mg P/g, q0.1 = 3.1974 mg P/g). Over the 90-day experimental period with O-Fe-BC, dissolved oxygen (DO) levels in the overlying water could maintain at ∼4 mg/L (peaking at ∼9.5 mg/L), and total phosphorus (TP) and soluble reactive phosphorus (SRP) levels decreased by over 96 %. The higher inorganic phosphorus content in the surface sediment-biochar mixture, along with the lower labile P and Fe concentration in the sediment pore water in the O-Fe-BC group compared to other groups, suggested the enhanced P immobilization. Further mechanism exploration revealed the combined roles of adsorption and microbial response, in which O-Fe-BC achieved efficient phosphate adsorption primarily through inner-sphere complexation via ligand exchange and keystone taxa (particularly Candidatus Electronema) played a crucial role in driving water chemistry divergence. Specially, these cable bacteria could provide large pools of Fe oxides in the surface sediment, binding with P to prevent its release, as supported by significant correlations between Ca. Electronema abundance and oxidation-reduction potential (ORP), TP, SRP, and sediment Fe-P variations. Additionally, a pot experiment with mung bean seedlings showed that the recovered O-Fe-BC significantly promoted the seed germination and growth, indicating its potential as a novel material for removing and recovering P from eutrophic waters. Taken together, our work provided a promising strategy for sustainable anoxia and P pollution mitigation, and also highlighted the indispensable roles of inner-sphere adsorption in P recovery and microbial keystone taxa in P cycling regulation.
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Affiliation(s)
- Xinyan Xiong
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210024, PR China
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210024, PR China.
| | - Chi Zhang
- College of Materials Science and Engineering, Hohai University, Changzhou 213200, PR China.
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2
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Bute TF, Wyness A, Wasserman RJ, Dondofema F, Keates C, Dalu T. Microbial community and extracellular polymeric substance dynamics in arid-zone temporary pan ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 932:173059. [PMID: 38723976 DOI: 10.1016/j.scitotenv.2024.173059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 05/12/2024]
Abstract
Microbial extracellular polymeric substances (EPS) are an important component in sediment ecology. However, most research is highly skewed towards the northern hemisphere and in more permanent systems. This paper investigates EPS (i.e., carbohydrates and proteins) dynamics in arid Austral zone temporary pans sediments. Colorimetric methods and sequence-based metagenomics techniques were employed in a series of small temporary pan ecosystems characterised by alternating wet and dry hydroperiods. Microbial community patterns of distribution were evaluated between seasons (hot-wet and cool-dry) and across depths (and inferred inundation period) based on estimated elevation. Carbohydrates generally occurred in relatively higher proportions than proteins; the carbohydrate:protein ratio was 2.8:1 and 1.6:1 for the dry and wet season respectively, suggesting that EPS found in these systems was largely diatom produced. The wet- hydroperiods (Carbohydrate mean 102 μg g-1; Protein mean 65 μg g-1) supported more EPS production as compared to the dry- hydroperiods (Carbohydrate mean 73 μg g-1; Protein mean 26 μg g-1). A total of 15,042 Unique Amplicon Sequence Variants (ASVs) were allocated to 51 bacterial phyla and 1127 genera. The most abundant genera had commonality in high temperature tolerance, with Firmicutes, Actinobacteria and Proteobacteria in high abundances. Microbial communities were more distinct between seasons compared to within seasons which further suggested that the observed metagenome functions could be seasonally driven. This study's findings implied that there were high levels of denitrification by mostly nitric oxide reductase and nitrite reductase enzymes. EPS production was high in the hot-wet season as compared to relatively lower rates of nitrification in the cool-dry season by ammonia monooxygenases. Both EPS quantities and metagenome functions were highly associated with availability of water, with high rates being mainly associated with wet- hydroperiods compared to dry- hydroperiods. These data suggest that extended dry periods threaten microbially mediated processes in temporary wetlands, with implications to loss of biodiversity by desiccation.
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Affiliation(s)
- Tafara F Bute
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa.
| | - Adam Wyness
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa; Scottish Association for Marine Science, Oban PA37 1QA, United Kingdom
| | - Ryan J Wasserman
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa; South African Institute for Aquatic Biodiversity, Makhanda 6140, South Africa
| | - Farai Dondofema
- Department of Geography and Environmental Sciences, University of Venda, Thohoyandou 0950, South Africa
| | - Chad Keates
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa; South African Institute for Aquatic Biodiversity, Makhanda 6140, South Africa
| | - Tatenda Dalu
- South African Institute for Aquatic Biodiversity, Makhanda 6140, South Africa; School of Biology and Environmental Sciences, University of Mpumalanga, Nelspruit 1200, South Africa
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3
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Baker IR, Girguis PR. Sulfur cycling likely obscures dynamic biologically-driven iron redox cycling in contemporary methane seep environments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13263. [PMID: 38705733 PMCID: PMC11070330 DOI: 10.1111/1758-2229.13263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 04/06/2024] [Indexed: 05/07/2024]
Abstract
Deep-sea methane seeps are amongst the most biologically productive environments on Earth and are often characterised by stable, low oxygen concentrations and microbial communities that couple the anaerobic oxidation of methane to sulfate reduction or iron reduction in the underlying sediment. At these sites, ferrous iron (Fe2+) can be produced by organoclastic iron reduction, methanotrophic-coupled iron reduction, or through the abiotic reduction by sulfide produced by the abundant sulfate-reducing bacteria at these sites. The prevalence of Fe2+in the anoxic sediments, as well as the availability of oxygen in the overlying water, suggests that seeps could also harbour communities of iron-oxidising microbes. However, it is unclear to what extent Fe2+ remains bioavailable and in solution given that the abiotic reaction between sulfide and ferrous iron is often assumed to scavenge all ferrous iron as insoluble iron sulfides and pyrite. Accordingly, we searched the sea floor at methane seeps along the Cascadia Margin for microaerobic, neutrophilic iron-oxidising bacteria, operating under the reasoning that if iron-oxidising bacteria could be isolated from these environments, it could indicate that porewater Fe2+ can persist is long enough for biology to outcompete pyritisation. We found that the presence of sulfate in our enrichment media muted any obvious microbially-driven iron oxidation with most iron being precipitated as iron sulfides. Transfer of enrichment cultures to sulfate-depleted media led to dynamic iron redox cycling relative to abiotic controls and sulfate-containing cultures, and demonstrated the capacity for biogenic iron (oxyhydr)oxides from a methane seep-derived community. 16S rRNA analyses revealed that removing sulfate drastically reduced the diversity of enrichment cultures and caused a general shift from a Gammaproteobacteria-domainated ecosystem to one dominated by Rhodobacteraceae (Alphaproteobacteria). Our data suggest that, in most cases, sulfur cycling may restrict the biological "ferrous wheel" in contemporary environments through a combination of the sulfur-adapted sediment-dwelling ecosystems and the abiotic reactions they influence.
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Affiliation(s)
- Isabel R. Baker
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Department of Earth and Planetary ScienceJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Peter R. Girguis
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
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4
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Fang X, Colina Blanco AE, Christl I, Le Bars M, Straub D, Kleindienst S, Planer-Friedrich B, Zhao FJ, Kappler A, Kretzschmar R. Simultaneously decreasing arsenic and cadmium in rice by soil sulfate and limestone amendment under intermittent flooding. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 347:123786. [PMID: 38484962 DOI: 10.1016/j.envpol.2024.123786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/22/2024] [Accepted: 03/12/2024] [Indexed: 03/19/2024]
Abstract
Water management in paddy soils can effectively reduce the soil-to-rice grain transfer of either As or Cd, but not of both elements simultaneously due to the higher mobility of As under reducing and Cd under oxidizing soil conditions. Limestone amendment, the common form of liming, is well known for decreasing Cd accumulation in rice grown on acidic soils. Sulfate amendment was suggested to effectively decrease As accumulation in rice, especially under intermittent soil flooding. To study the unknown effects of combined sulfate and limestone amendment under intermittent flooding for simultaneously decreasing As and Cd in rice, we performed a pot experiment using an acidic sandy loam paddy soil. We also included a clay loam paddy soil to study the role of soil texture in low-As rice production under intermittent flooding. We found that liming not only decreased rice Cd concentrations but also greatly decreased dimethylarsenate (DMA) accumulation in rice. We hypothesize that this is due to suppressed sulfate reduction, As methylation, and As thiolation by liming in the sulfate-amended soil and a higher share of deprotonated DMA at higher pH which is taken up less readily than protonated DMA. Decreased gene abundance of potential soil sulfate-reducers by liming further supported our hypothesis. Combined sulfate and limestone amendment to the acidic sandy loam soil produced rice with 43% lower inorganic As, 72% lower DMA, and 68% lower Cd compared to the control soil without amendment. A tradeoff between soil aeration and water availability was observed for the clay loam soil, suggesting difficulties to decrease As in rice while avoiding plant water stress under intermittent flooding in fine-textured soils. Our results suggest that combining sulfate amendment, liming, and intermittent flooding can help to secure rice safety when the presence of both As and Cd in coarse-textured soils is of concern.
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Affiliation(s)
- Xu Fang
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich, CH-8092, Zurich, Switzerland.
| | - Andrea E Colina Blanco
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER), University of Bayreuth, 95440, Bayreuth, Germany
| | - Iso Christl
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Maureen Le Bars
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Daniel Straub
- Quantitative Biology Center (QBiC), University of Tuebingen, 72076, Tuebingen, Germany; Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tuebingen, 72076, Germany
| | - Sara Kleindienst
- Microbial Ecology, Department of Geosciences, University of Tuebingen, 72076, Tuebingen, Germany; Now: Department of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), University of Stuttgart, Stuttgart, 70569, Germany
| | - Britta Planer-Friedrich
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BAYCEER), University of Bayreuth, 95440, Bayreuth, Germany
| | - Fang-Jie Zhao
- College of Resources and Environmental Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Andreas Kappler
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tuebingen, 72076, Germany; Geomicrobiology, Department of Geosciences, Tuebingen University, 72076, Tuebingen, Germany
| | - Ruben Kretzschmar
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich, CH-8092, Zurich, Switzerland
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5
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Zheng Y, Wang H, Liu Y, Liu P, Zhu B, Zheng Y, Li J, Chistoserdova L, Ren ZJ, Zhao F. Electrochemically coupled CH 4 and CO 2 consumption driven by microbial processes. Nat Commun 2024; 15:3097. [PMID: 38600111 PMCID: PMC11006836 DOI: 10.1038/s41467-024-47445-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 03/27/2024] [Indexed: 04/12/2024] Open
Abstract
The chemical transformations of methane (CH4) and carbon dioxide (CO2) greenhouse gases typically have high energy barriers. Here we present an approach of strategic coupling of CH4 oxidation and CO2 reduction in a switched microbial process governed by redox cycling of iron minerals under temperate conditions. The presence of iron minerals leads to an obvious enhancement of carbon fixation, with the minerals acting as the electron acceptor for CH4 oxidation and the electron donor for CO2 reduction, facilitated by changes in the mineral structure. The electron flow between the two functionally active microbial consortia is tracked through electrochemistry, and the energy metabolism in these consortia is predicted at the genetic level. This study offers a promising strategy for the removal of CH4 and CO2 in the natural environment and proposes an engineering technique for the utilization of major greenhouse gases.
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Affiliation(s)
- Yue Zheng
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
- State Key Laboratory of Marine Environmental Science, and College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Huan Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
- State Key Laboratory of Marine Environmental Science, and College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Yan Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
- Laboratory for Marine Geology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | - Peiyu Liu
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
- Laboratory for Marine Geology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | - Baoli Zhu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions and Taoyuan Agro-ecosystem Research Station, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
| | - Yanning Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jinhua Li
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
- Laboratory for Marine Geology, Qingdao Marine Science and Technology Center, Qingdao, 266237, China
| | | | - Zhiyong Jason Ren
- Department of Civil and Environmental Engineering, and Andlinger Center for Energy and the Environment, Princeton University, 41 Olden St., Princeton, NJ, 08540, USA.
| | - Feng Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
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6
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Xiong X, Li Y, Zhang C. Cable bacteria: Living electrical conduits for biogeochemical cycling and water environment restoration. WATER RESEARCH 2024; 253:121345. [PMID: 38394932 DOI: 10.1016/j.watres.2024.121345] [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: 11/29/2023] [Revised: 02/17/2024] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
Since the discovery of multicellular cable bacteria in marine sediments in 2012, they have attracted widespread attention and interest due to their unprecedented ability to generate and transport electrical currents over centimeter-scale long-range distances. The cosmopolitan distribution of cable bacteria in both marine and freshwater systems, along with their substantial impact on local biogeochemistry, has uncovered their important role in element cycling and ecosystem functioning of aquatic environments. Considerable research efforts have been devoted to the potential utilization of cable bacteria for various water management purposes during the past few years. However, there lacks a critical summary on the advances and contributions of cable bacteria to biogeochemical cycles and water environment restoration. This review aims to provide an up-to-date and comprehensive overview of the current research on cable bacteria, with a particular view on their participation in aquatic biogeochemical cycles and promising applications in water environment restoration. It systematically analyzes (i) the global distribution of cable bacteria in aquatic ecosystems and the major environmental factors affecting their survival, diversity, and composition, (ii) the interactive associations between cable bacteria and other microorganisms as well as aquatic plants and infauna, (iii) the underlying role of cable bacteria in sedimentary biogeochemical cycling of essential elements including but not limited to sulfur, iron, phosphorus, and nitrogen, (iv) the practical explorations of cable bacteria for water pollution control, greenhouse gas emission reduction, aquatic ecological environment restoration, as well as possible combinations with other water remediation technologies. It is believed to give a step-by-step introduction to progress on cable bacteria, highlight key findings, opportunities and challenges of using cable bacteria for water environment restoration, and propose directions for further exploration.
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Affiliation(s)
- Xinyan Xiong
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210024, PR China
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210024, PR China.
| | - Chi Zhang
- College of Materials Science and Engineering, Hohai University, Changzhou 213200, PR China.
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7
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Vallejos A, Sola F, Vargas-García MC, Mancuso M. Microbial-induced MnO 2 precipitation in a carbonate coastal aquifer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:169968. [PMID: 38220013 DOI: 10.1016/j.scitotenv.2024.169968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/18/2023] [Accepted: 01/04/2024] [Indexed: 01/16/2024]
Abstract
A study was carried out to identify biogeochemical reactions along a transect of a coastal dolomitic aquifer. In this transect, the physicochemical parameters of the groundwater as well as the microbial composition of samples taken at different depths and salinities were measured. Many of the dissolved ions measured in the groundwater follow a pattern that reflects the distribution of the water masses (fresh, interface and salt) in the aquifer, while others such as Ca and Mg ions deviate from this trend by identifying the zones of maximum dissolution of the carbonate matrix. The concentrations of minor ions, such as Fe and Mn, also follow a singular pattern, with maximum concentrations in the reducing zones of the aquifer and lower values in the oxidizing zones. Precipitates of Mn oxides along with other metals, such as Fe, Ba, Zn and Ni, were observed in the saline zone displaying oxidizing conditions close to the coastline, where a continuous core was recovered. This zone, which is located below the freshwater-seawater mixing zone and features percentages of seawater higher than 80 %, is characterized by the presence of Marinobacter as the predominant genus. These bacteria are also related to the formation of Mn-rich polymetallic oxides in other contexts such as the ocean floor (Wang et al., 2012; Cao et al., 2021). All in all, a biogeochemical reaction model is proposed that describes the formation of these oxides in areas close to the discharge zone of coastal aquifers. To do this, it has been necessary to integrate the results obtained from geochemical, hydrogeological and microbiological information.
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Affiliation(s)
- A Vallejos
- Water Resources and Environmental Geology, Department of Biology & Geology, University of Almería, Spain.
| | - F Sola
- Water Resources and Environmental Geology, Department of Biology & Geology, University of Almería, Spain
| | - M C Vargas-García
- Unit of Microbiology, Department of Biology and Geology, CITE II-B, University of Almeria, Marine Campus of International Excellence CEIMAR, 04120 Almeria, Spain
| | - M Mancuso
- Engineering and Environmental Technology Department, Universidade Federal de Santa Maria, UFSM, Brazil
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8
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Hiralal A, Geelhoed JS, Hidalgo-Martinez S, Smets B, van Dijk JR, Meysman FJR. Closing the genome of unculturable cable bacteria using a combined metagenomic assembly of long and short sequencing reads. Microb Genom 2024; 10:001197. [PMID: 38376381 PMCID: PMC10926707 DOI: 10.1099/mgen.0.001197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/23/2024] [Indexed: 02/21/2024] Open
Abstract
Many environmentally relevant micro-organisms cannot be cultured, and even with the latest metagenomic approaches, achieving complete genomes for specific target organisms of interest remains a challenge. Cable bacteria provide a prominent example of a microbial ecosystem engineer that is currently unculturable. They occur in low abundance in natural sediments, but due to their capability for long-distance electron transport, they exert a disproportionately large impact on the biogeochemistry of their environment. Current available genomes of marine cable bacteria are highly fragmented and incomplete, hampering the elucidation of their unique electrogenic physiology. Here, we present a metagenomic pipeline that combines Nanopore long-read and Illumina short-read shotgun sequencing. Starting from a clonal enrichment of a cable bacterium, we recovered a circular metagenome-assembled genome (5.09 Mbp in size), which represents a novel cable bacterium species with the proposed name Candidatus Electrothrix scaldis. The closed genome contains 1109 novel identified genes, including key metabolic enzymes not previously described in incomplete genomes of cable bacteria. We examined in detail the factors leading to genome closure. Foremost, native, non-amplified long reads are crucial to resolve the many repetitive regions within the genome of cable bacteria, and by analysing the whole metagenomic assembly, we found that low strain diversity is key for achieving genome closure. The insights and approaches presented here could help achieve genome closure for other keystone micro-organisms present in complex environmental samples at low abundance.
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Affiliation(s)
- Anwar Hiralal
- Geobiology Research Group, University of Antwerp, Antwerp, Belgium
| | | | | | - Bent Smets
- Geobiology Research Group, University of Antwerp, Antwerp, Belgium
| | | | - Filip J. R. Meysman
- Geobiology Research Group, University of Antwerp, Antwerp, Belgium
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
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9
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Romanowicz KJ, Crump BC, Kling GW. Genomic evidence that microbial carbon degradation is dominated by iron redox metabolism in thawing permafrost. ISME COMMUNICATIONS 2023; 3:124. [PMID: 37996661 PMCID: PMC10667234 DOI: 10.1038/s43705-023-00326-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 10/18/2023] [Accepted: 10/27/2023] [Indexed: 11/25/2023]
Abstract
Microorganisms drive many aspects of organic carbon cycling in thawing permafrost soils, but the compositional trajectory of the post-thaw microbiome and its metabolic activity remain uncertain, which limits our ability to predict permafrost-climate feedbacks in a warming world. Using quantitative metabarcoding and metagenomic sequencing, we determined relative and absolute changes in microbiome composition and functional gene abundance during thaw incubations of wet sedge tundra collected from northern Alaska, USA. Organic soils from the tundra active-layer (0-50 cm), transition-zone (50-70 cm), and permafrost (70+ cm) depths were incubated under reducing conditions at 4 °C for 30 days to mimic an extended thaw duration. Following extended thaw, we found that iron (Fe)-cycling Gammaproteobacteria, specifically the heterotrophic Fe(III)-reducing Rhodoferax sp. and chemoautotrophic Fe(II)-oxidizing Gallionella sp., increased by 3-5 orders of magnitude in absolute abundance within the transition-zone and permafrost microbiomes, accounting for 65% of community abundance. We also found that the abundance of genes for Fe(III) reduction (e.g., MtrE) and Fe(II) oxidation (e.g., Cyc1) increased concurrently with genes for benzoate degradation and pyruvate metabolism, in which pyruvate is used to generate acetate that can be oxidized, along with benzoate, to CO2 when coupled with Fe(III) reduction. Gene abundance for CH4 metabolism decreased following extended thaw, suggesting dissimilatory Fe(III) reduction suppresses acetoclastic methanogenesis under reducing conditions. Our genomic evidence indicates that microbial carbon degradation is dominated by iron redox metabolism via an increase in gene abundance associated with Fe(III) reduction and Fe(II) oxidation during initial permafrost thaw, likely increasing microbial respiration while suppressing methanogenesis in wet sedge tundra.
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Affiliation(s)
- Karl J Romanowicz
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - George W Kling
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA.
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10
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Giangeri G, Tsapekos P, Gaspari M, Ghofrani-Isfahani P, Hong Lin MKT, Treu L, Kougias P, Campanaro S, Angelidaki I. Magnetite Alters the Metabolic Interaction between Methanogens and Sulfate-Reducing Bacteria. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16399-16413. [PMID: 37862709 PMCID: PMC10620991 DOI: 10.1021/acs.est.3c05948] [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: 07/25/2023] [Revised: 09/28/2023] [Accepted: 09/28/2023] [Indexed: 10/22/2023]
Abstract
It is known that the presence of sulfate decreases the methane yield in the anaerobic digestion systems. Sulfate-reducing bacteria can convert sulfate to hydrogen sulfide competing with methanogens for substrates such as H2 and acetate. The present work aims to elucidate the microbial interactions in biogas production and assess the effectiveness of electron-conductive materials in restoring methane production after exposure to high sulfate concentrations. The addition of magnetite led to a higher methane content in the biogas and a sharp decrease in the level of hydrogen sulfide, indicating its beneficial effects. Furthermore, the rate of volatile fatty acid consumption increased, especially for butyrate, propionate, and acetate. Genome-centric metagenomics was performed to explore the main microbial interactions. The interaction between methanogens and sulfate-reducing bacteria was found to be both competitive and cooperative, depending on the methanogenic class. Microbial species assigned to the Methanosarcina genus increased in relative abundance after magnetite addition together with the butyrate oxidizing syntrophic partners, in particular belonging to the Syntrophomonas genus. Additionally, Ruminococcus sp. DTU98 and other species assigned to the Chloroflexi phylum were positively correlated to the presence of sulfate-reducing bacteria, suggesting DIET-based interactions. In conclusion, this study provides new insights into the application of magnetite to enhance the anaerobic digestion performance by removing hydrogen sulfide, fostering DIET-based syntrophic microbial interactions, and unraveling the intricate interplay of competitive and cooperative interactions between methanogens and sulfate-reducing bacteria, influenced by the specific methanogenic group.
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Affiliation(s)
- Ginevra Giangeri
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Panagiotis Tsapekos
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Maria Gaspari
- Department
of Hydraulics, Soil Science and Agricultural Engineering, Faculty
of Agriculture, Aristotle University of
Thessaloniki, GR-54124 Thessaloniki, Greece
| | - Parisa Ghofrani-Isfahani
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Marie Karen Tracy Hong Lin
- National
Centre for Nano Fabrication and Characterization, Technical University of Denmark, Kgs, DK-2800 Lyngby, Denmark
| | - Laura Treu
- Department
of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
| | - Panagiotis Kougias
- Hellenic
Agricultural Organization Dimitra, Soil
and Water Resources Institute, Thermi, GR-54124 Thessaloniki, Greece
| | - Stefano Campanaro
- Department
of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
| | - Irini Angelidaki
- Department
of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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11
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Dick JM, Meng D. Community- and genome-based evidence for a shaping influence of redox potential on bacterial protein evolution. mSystems 2023; 8:e0001423. [PMID: 37289197 PMCID: PMC10308962 DOI: 10.1128/msystems.00014-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 02/28/2023] [Indexed: 06/09/2023] Open
Abstract
Despite deep interest in how environments shape microbial communities, whether redox conditions influence the sequence composition of genomes is not well known. We predicted that the carbon oxidation state (ZC) of protein sequences would be positively correlated with redox potential (Eh). To test this prediction, we used taxonomic classifications for 68 publicly available 16S rRNA gene sequence data sets to estimate the abundances of archaeal and bacterial genomes in river & seawater, lake & pond, geothermal, hyperalkaline, groundwater, sediment, and soil environments. Locally, ZC of community reference proteomes (i.e., all the protein sequences in each genome, weighted by taxonomic abundances but not by protein abundances) is positively correlated with Eh corrected to pH 7 (Eh7) for the majority of data sets for bacterial communities in each type of environment, and global-scale correlations are positive for bacterial communities in all environments. In contrast, archaeal communities show approximately equal frequencies of positive and negative correlations in individual data sets, and a positive pan-environmental correlation for archaea only emerges after limiting the analysis to samples with reported oxygen concentrations. These results provide empirical evidence that geochemistry modulates genome evolution and may have distinct effects on bacteria and archaea. IMPORTANCE The identification of environmental factors that influence the elemental composition of proteins has implications for understanding microbial evolution and biogeography. Millions of years of genome evolution may provide a route for protein sequences to attain incomplete equilibrium with their chemical environment. We developed new tests of this chemical adaptation hypothesis by analyzing trends of the carbon oxidation state of community reference proteomes for microbial communities in local- and global-scale redox gradients. The results provide evidence for widespread environmental shaping of the elemental composition of protein sequences at the community level and establish a rationale for using thermodynamic models as a window into geochemical effects on microbial community assembly and evolution.
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Affiliation(s)
- Jeffrey M. Dick
- Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring of Ministry of Education, School of Geosciences and Info-Physics, Central South University, Changsha, China
| | - Delong Meng
- Key Laboratory of Biometallurgy of Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha, China
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12
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Bjerg JJ, Lustermans JJM, Marshall IPG, Mueller AJ, Brokjær S, Thorup CA, Tataru P, Schmid M, Wagner M, Nielsen LP, Schramm A. Cable bacteria with electric connection to oxygen attract flocks of diverse bacteria. Nat Commun 2023; 14:1614. [PMID: 36959175 PMCID: PMC10036481 DOI: 10.1038/s41467-023-37272-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 03/08/2023] [Indexed: 03/25/2023] Open
Abstract
Cable bacteria are centimeter-long filamentous bacteria that conduct electrons via internal wires, thus coupling sulfide oxidation in deeper, anoxic sediment with oxygen reduction in surface sediment. This activity induces geochemical changes in the sediment, and other bacterial groups appear to benefit from the electrical connection to oxygen. Here, we report that diverse bacteria swim in a tight flock around the anoxic part of oxygen-respiring cable bacteria and disperse immediately when the connection to oxygen is disrupted (by cutting the cable bacteria with a laser). Raman microscopy shows that flocking bacteria are more oxidized when closer to the cable bacteria, but physical contact seems to be rare and brief, which suggests potential transfer of electrons via unidentified soluble intermediates. Metagenomic analysis indicates that most of the flocking bacteria appear to be aerobes, including organotrophs, sulfide oxidizers, and possibly iron oxidizers, which might transfer electrons to cable bacteria for respiration. The association and close interaction with such diverse partners might explain how oxygen via cable bacteria can affect microbial communities and processes far into anoxic environments.
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Affiliation(s)
- Jesper J Bjerg
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark.
- Microbial Systems Technology Excellence Centre, University of Antwerp, Wilrijk, Belgium.
| | - Jamie J M Lustermans
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Ian P G Marshall
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Anna J Mueller
- Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology (DOME), University of Vienna, Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
| | - Signe Brokjær
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Casper A Thorup
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Paula Tataru
- Bioinformatics Research Center (BiRC), Aarhus University, Aarhus C, Denmark
| | - Markus Schmid
- Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology (DOME), University of Vienna, Vienna, Austria
| | - Michael Wagner
- Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology (DOME), University of Vienna, Vienna, Austria
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Lars Peter Nielsen
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Andreas Schramm
- Center for Electromicrobiology (CEM), Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark.
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13
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Lustermans JJM, Bjerg JJ, Burdorf LDW, Nielsen LP, Schramm A, Marshall IPG. Persistent flocks of diverse motile bacteria in long-term incubations of electron-conducting cable bacteria, Candidatus Electronema aureum. Front Microbiol 2023; 14:1008293. [PMID: 36910179 PMCID: PMC9998039 DOI: 10.3389/fmicb.2023.1008293] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Cable bacteria are centimeters-long filamentous bacteria that oxidize sulfide in anoxic sediment layers and reduce oxygen at the oxic-anoxic interface, connecting these reactions via electron transport. The ubiquitous cable bacteria have a major impact on sediment geochemistry and microbial communities. This includes diverse bacteria swimming around cable bacteria as dense flocks in the anoxic zone, where the cable bacteria act as chemotactic attractant. We hypothesized that flocking only appears when cable bacteria are highly abundant and active. We set out to discern the timing and drivers of flocking over 81 days in an enrichment culture of the freshwater cable bacterium Candidatus Electronema aureum GS by measuring sediment microprofiles of pH, oxygen, and electric potential as a proxy of cable bacteria activity. Cable bacterial relative abundance was quantified by 16S rRNA amplicon sequencing, and microscopy observations to determine presence of flocking. Flocking was always observed at some cable bacteria, irrespective of overall cable bacteria rRNA abundance, activity, or sediment pH. Diverse cell morphologies of flockers were observed, suggesting that flocking is not restricted to a specific, single bacterial associate. This, coupled with their consistent presence supports a common mechanism of interaction, likely interspecies electron transfer via electron shuttles. Flocking appears exclusively linked to the electron conducting activity of the individual cable bacteria.
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Affiliation(s)
- Jamie J. M. Lustermans
- Section for Microbiology, Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Jesper J. Bjerg
- Section for Microbiology, Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
- Department of Biology, Microbial Systems Technology Excellence Centre, University of Antwerp, Wilrijk, Belgium
| | - Laurine D. W. Burdorf
- Section for Microbiology, Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
- Department of Biology, Microbial Systems Technology Excellence Centre, University of Antwerp, Wilrijk, Belgium
| | - Lars Peter Nielsen
- Section for Microbiology, Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Ian P. G. Marshall
- Section for Microbiology, Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
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14
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Cooper RE, Finck J, Chan C, Küsel K. Mixotrophy broadens the ecological niche range of the iron oxidizer Sideroxydans sp. CL21 isolated from an iron-rich peatland. FEMS Microbiol Ecol 2023; 99:6979798. [PMID: 36623865 PMCID: PMC9925335 DOI: 10.1093/femsec/fiac156] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/17/2022] [Accepted: 01/06/2023] [Indexed: 01/11/2023] Open
Abstract
Sideroxydans sp. CL21 is a microaerobic, acid-tolerant Fe(II)-oxidizer, isolated from the Schlöppnerbrunnen fen. Since the genome size of Sideroxydans sp. CL21 is 21% larger than that of the neutrophilic Sideroxydans lithotrophicus ES-1, we hypothesized that strain CL21 contains additional metabolic traits to thrive in the fen. The common genomic content of both strains contains homologs of the putative Fe(II) oxidation genes, mtoAB and cyc2. A large part of the accessory genome in strain CL21 contains genes linked to utilization of alternative electron donors, including NiFe uptake hydrogenases, and genes encoding lactate uptake and utilization proteins, motility and biofilm formation, transposable elements, and pH homeostasis mechanisms. Next, we incubated the strain in different combinations of electron donors and characterized the fen microbial communities. Sideroxydans spp. comprised 3.33% and 3.94% of the total relative abundance in the peatland soil and peatland water, respectively. Incubation results indicate Sideroxydans sp. CL21 uses H2 and thiosulfate, while lactate only enhances growth when combined with Fe, H2, or thiosulfate. Rates of H2 utilization were highest in combination with other substrates. Thus, Sideroxydans sp. CL21 is a mixotroph, growing best by simultaneously using substrate combinations, which helps to thrive in dynamic and complex habitats.
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Affiliation(s)
- Rebecca E Cooper
- Aquatic Geomicrobiology, Institute of Biodiversity, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Jessica Finck
- Aquatic Geomicrobiology, Institute of Biodiversity, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Clara Chan
- School of Marine Science and Policy, University of Delaware, Newark, DE 19716, United States,Delaware Biotechnology Institute, University of Delaware, Newark, DE 19713, United States,Department of Earth Sciences, University of Delaware, Newark, DE 19716, United States
| | - Kirsten Küsel
- Corresponding author. Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Str. 159, 07743 Jena, Germany. Tel: +49 3641 949461; Fax: +49 3641 949462; E-mail:
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15
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Vasquez-Cardenas D, Hidalgo-Martinez S, Hulst L, Thorleifsdottir T, Helgason GV, Eiriksson T, Geelhoed JS, Agustsson T, Moodley L, Meysman FJR. Biogeochemical impacts of fish farming on coastal sediments: Insights into the functional role of cable bacteria. Front Microbiol 2022; 13:1034401. [PMID: 36620049 PMCID: PMC9814725 DOI: 10.3389/fmicb.2022.1034401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Fish farming in sea cages is a growing component of the global food industry. A prominent ecosystem impact of this industry is the increase in the downward flux of organic matter, which stimulates anaerobic mineralization and sulfide production in underlying sediments. When free sulfide is released to the overlying water, this can have a toxic effect on local marine ecosystems. The microbially-mediated process of sulfide oxidation has the potential to be an important natural mitigation and prevention strategy that has not been studied in fish farm sediments. We examined the microbial community composition (DNA-based 16S rRNA gene) underneath two active fish farms on the Southwestern coast of Iceland and performed laboratory incubations of resident sediment. Field observations confirmed the strong geochemical impact of fish farming on the sediment (up to 150 m away from cages). Sulfide accumulation was evidenced under the cages congruent with a higher supply of degradable organic matter from the cages. Phylogenetically diverse microbes capable of sulfide detoxification were present in the field sediment as well as in lab incubations, including cable bacteria (Candidatus Electrothrix), which display a unique metabolism based on long-distance electron transport. Microsensor profiling revealed that the activity of cable bacteria did not exert a dominant impact on the geochemistry of fish farm sediment at the time of sampling. However, laboratory incubations that mimic the recovery process during fallowing, revealed successful enrichment of cable bacteria within weeks, with concomitant high sulfur-oxidizing activity. Overall our results give insight into the role of microbially-mediated sulfide detoxification in aquaculture impacted sediments.
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Affiliation(s)
- Diana Vasquez-Cardenas
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands,Geobiology, Department of Biology, University of Antwerp, Antwerp, Belgium,*Correspondence: Diana Vasquez-Cardenas,
| | | | - Lucas Hulst
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | | | | | | | | | | | - Leon Moodley
- NORCE Norwegian Research Centre, Randaberg, Norway
| | - Filip J. R. Meysman
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands,Geobiology, Department of Biology, University of Antwerp, Antwerp, Belgium
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16
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Ke T, Zhang D, Guo H, Xiu W, Zhao Y. Geogenic arsenic and arsenotrophic microbiome in groundwater from the Hetao Basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158549. [PMID: 36075436 DOI: 10.1016/j.scitotenv.2022.158549] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/28/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
High arsenic (As) in groundwater is an environmental issue of global concern, which is closely related to microbe-mediated As biogeochemical cycling. However, the distribution of genes related to As cycling and underlying microbial As biogeochemical processes in high As groundwater remain elusive. Hence, we profiled the As cycling genes (arsC, arrA, and aioA genes) and indigenous microbial communities in groundwater from a typical high As area, the Hetao Basin from China, using amplicon sequencing and qPCR techniques. Here, we revealed the significant difference in microbial community structure between low As groundwater samples (LG) and high As groundwater samples (HG). Acinetobacter, Thiovirga, Hydrogenophaga, and Sulfurimonas were dominant in LG, while Aquabcterium, Acinetobacter, Sphingomonas, Pseudomonas, Desulfomicrobium, Hydrogenophaga, and Nitrospira were predominant in HG. Shannon and Chao indices of the microbial communities in HG were significantly higher than those of in LG. Alpha diversity and abundance of arsC and arrA genes were higher than those of aioA genes. The significant positive correlation was uncovered between the abundances of arsC and aioA genes, suggesting the cooccurrence of As functional genes in groundwater. Sphingopyxis, Agrobacterium, Klebsiella, Hoeflea, and Aeromonas represented the dominant taxa within the As (V) reducers communities. Distance-based redundancy analysis showed that ORP, pH, Astot, Mn, and DOC were the key factors shaping the diverse microbial populations, while ORP, S2-, As(III), Fe(II), NH4+, pH, Mn, SO42-, As(V), temperature, and P as the main drivers affecting arsenotrophic microbiota. This work provides an insight into microbial communities linked to As biogeochemical processes in high As groundwater, playing a fundamental role in groundwater As cycling.
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Affiliation(s)
- Tiantian Ke
- Ministry of Education, Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, China
| | - Di Zhang
- Ministry of Education, Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, China
| | - Huaming Guo
- Ministry of Education, Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, China.
| | - Wei Xiu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, China
| | - Yi Zhao
- Ministry of Education, Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, China
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17
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Liau P, Kim C, Saxton MA, Malkin SY. Microbial succession in a marine sediment: Inferring interspecific microbial interactions with marine cable bacteria. Environ Microbiol 2022; 24:6348-6364. [PMID: 36178156 PMCID: PMC10092204 DOI: 10.1111/1462-2920.16230] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/27/2022] [Indexed: 01/12/2023]
Abstract
Cable bacteria are long, filamentous, multicellular bacteria that grow in marine sediments and couple sulfide oxidation to oxygen reduction over centimetre-scale distances via long-distance electron transport. Cable bacteria can strongly modify biogeochemical cycling and may affect microbial community networks. Here we examine interspecific interactions with marine cable bacteria (Ca. Electrothrix) by monitoring the succession of 16S rRNA amplicons (DNA and RNA) and cell abundance across depth and time, contrasting sediments with and without cable bacteria growth. In the oxic zone, cable bacteria activity was positively associated with abundant predatory bacteria (Bdellovibrionota, Myxococcota, Bradymonadales), indicating putative predation on cathodic cells. At suboxic depths, cable bacteria activity was positively associated with sulfate-reducing and magnetotactic bacteria, consistent with cable bacteria functioning as ecosystem engineers that modify their local biogeochemical environment, benefitting certain microbes. Cable bacteria activity was negatively associated with chemoautotrophic sulfur-oxidizing Gammaproteobacteria (Thiogranum, Sedimenticola) at oxic depths, suggesting competition, and positively correlated with these taxa at suboxic depths, suggesting syntrophy and/or facilitation. These observations are consistent with chemoautotrophic sulfur oxidizers benefitting from an oxidizing potential imparted by cable bacteria at suboxic depths, possibly by using cable bacteria as acceptors for electrons or electron equivalents, but by an as yet enigmatic mechanism.
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Affiliation(s)
- Pinky Liau
- Horn Point Laboratory, University of Maryland Center for Environmental Science (UMCES), Cambridge, Maryland, USA
| | - Carol Kim
- Horn Point Laboratory, University of Maryland Center for Environmental Science (UMCES), Cambridge, Maryland, USA
| | - Matthew A Saxton
- Department of Biological Sciences, Miami University, Middletown, Ohio, USA
| | - Sairah Y Malkin
- Horn Point Laboratory, University of Maryland Center for Environmental Science (UMCES), Cambridge, Maryland, USA
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18
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Li S, Diao M, Wang S, Zhu X, Dong X, Strous M, Ji G. Distinct oxygen isotope fractionations driven by different electron donors during microbial nitrate reduction in lake sediments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:812-821. [PMID: 35691702 DOI: 10.1111/1758-2229.13101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 05/29/2022] [Indexed: 06/15/2023]
Abstract
Microbial nitrate reduction can be driven by organic carbon oxidation, as well as by inorganic electron donors, such as reduced forms of sulfur and iron. An apparent inverse oxygen isotope fractionation effect was observed during nitrate reduction in sediment incubations from five sampling sites of a freshwater lake, Hongze Lake, China. Incubations with organic and inorganic electron donor additions were performed. Especially, the inverse oxygen isotope effect was intensified after glucose addition, whereas the incubations with sulfide and Fe2+ showed normal fractionation factors. Nitrate reductase encoding genes, napA and narG, were analysed with metagenomics. Higher napA/narG ratios were associated with higher oxygen fractionation factors. The most abundant clade (59%) of NapA in the incubation with glucose was affiliated with Rhodocyclales. In contrast, it only accounted for 8%-9% of NapA in the incubations with sulfide and Fe2+ . Differences in nitrate reductases might explain different oxygen isotope effects. Our findings also suggested that large variance of O-nitrate isotope fractionations might have to be considered in the interpretation of natural isotope records.
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Affiliation(s)
- Shengjie Li
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Muhe Diao
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Shuo Wang
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
| | - Xianfang Zhu
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
| | - Xiaoli Dong
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Marc Strous
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing, China
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19
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Wang Z, Liu F, Li E, Yuan Y, Yang Y, Xu M, Qiu R. Network analysis reveals microbe-mediated impacts of aeration on deep sediment layer microbial communities. Front Microbiol 2022; 13:931585. [PMID: 36246296 PMCID: PMC9561788 DOI: 10.3389/fmicb.2022.931585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/08/2022] [Indexed: 11/24/2022] Open
Abstract
Over-aeration is a common remediation strategy for black and odorous water bodies, in which oxygen is introduced to impact aquatic microbial communities as an electron acceptor of high redox potential. In this study, black-odorous freshwater sediments were cultured for 9 weeks under aeration to investigate microbial covariations at different depths and time points. Based on community 16S rRNA gene sequencing, the microbial covariations were visualized using phylogenetic microbial ecological networks (pMENs). In the spatial scale, we identified smaller and more compact pMENs across all layers compared with the anaerobic control sediments, in terms of network size, average node connectivity, and modularity. The aerated middle layer had the most connectors, the least module hubs, a network hub, shorter average path length, and predominantly positive covariations. In addition, a significant sulfate accumulation in the aerated middle layer indicated the most intense sulfide oxidation, possibly because aeration prompted sediment surface Desulfobulbaceae, known as cable bacteria, to reach the middle layer. In the time scale, similarly, aeration led to smaller pMEN sizes and higher portions of positive covariations. Therefore, we conclude that elevated dissolved oxygen at the water-sediment interface may impact not only the surface sediment but also the subsurface and/or deep sediment microbial communities mediated by microorganisms, particularly by Desulfobulbaceae.
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Affiliation(s)
- Zhenyu Wang
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Feifei Liu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Enze Li
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Yongqiang Yuan
- Key Laboratory of Karst Georesources and Environment, Ministry of Education, College of Resources and Environmental Engineering, Guizhou University, Guiyang, China
| | - Yonggang Yang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Meiying Xu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
- Meiying Xu
| | - Rongliang Qiu
- Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- *Correspondence: Rongliang Qiu
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20
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Li C, Reimers CE, Chace PJ. Protocol for using autoclaved intertidal sediment as a medium to enrich marine cable bacteria. STAR Protoc 2022; 3:101604. [PMID: 35990745 PMCID: PMC9389416 DOI: 10.1016/j.xpro.2022.101604] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Cable bacteria (CB) are non-isolated filamentous bacteria in the family of Desulfobulbaceae, known for fostering centimeter-long electron transfer in sediments with pronounced redox zonation. This protocol details steps to extract CB filaments from cultured natural sediment, inoculate autoclaved sediment with extracted filaments, and subsequently evaluate the growth and enrichment of CB. We also describe the approaches for collecting suitable sediment, preparing autoclaved sediment, and manufacturing glass needles and hooks for the extraction of CB. Prepare autoclaved sediment as an enrichment medium for cable bacteria Manufacture glass needles and hooks as tools to extract cable bacteria Video demonstration of cable bacteria extraction and autoclaved sediment inoculation Recover prolific cable bacteria biomass grown in autoclaved sediment
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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21
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Lueder U, Maisch M, Jørgensen BB, Druschel G, Schmidt C, Kappler A. Growth of microaerophilic Fe(II)-oxidizing bacteria using Fe(II) produced by Fe(III) photoreduction. GEOBIOLOGY 2022; 20:421-434. [PMID: 35014744 DOI: 10.1111/gbi.12485] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/10/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Iron(II) (Fe(II)) can be formed by abiotic Fe(III) photoreduction, particularly when Fe(III) is organically complexed. Light-influenced environments often overlap or even coincide with oxic or microoxic geochemical conditions, for example, in sediments. So far, it is unknown whether microaerophilic Fe(II)-oxidizing bacteria are able to use the Fe(II) produced by Fe(III) photoreduction as electron donor. Here, we present an adaption of the established agar-stabilized gradient tube approach in comparison with liquid cultures for the cultivation of microaerophilic Fe(II)-oxidizing microorganisms by using a ferrihydrite-citrate mixture undergoing Fe(III) photoreduction as Fe(II) source. We quantified oxygen and Fe(II) gradients with amperometric and voltammetric microelectrodes and evaluated microbial growth by qPCR of 16S rRNA genes. We showed that gradients of dissolved Fe(II) (maximum Fe(II) concentration of 1.25 mM) formed in the gradient tubes when incubated in blue or UV light (400-530 nm or 350-400 nm). Various microaerophilic Fe(II)-oxidizing bacteria (Curvibacter sp. and Gallionella sp.) grew by oxidizing Fe(II) that was produced in situ by Fe(III) photoreduction. Best growth for these species, based on highest gene copy numbers, was observed in incubations using UV light in both liquid culture and gradient tubes containing 8 mM ferrihydrite-citrate mixtures (1:1), due to continuous light-induced Fe(II) formation. Microaerophilic Fe(II)-oxidizing bacteria contributed up to 40% to the overall Fe(II) oxidation within 24 h of incubation in UV light. Our results highlight the potential importance of Fe(III) photoreduction as a source of Fe(II) for Fe(II)-oxidizing bacteria by providing Fe(II) in illuminated environments, even under microoxic conditions.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
| | - Markus Maisch
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
| | - Bo Barker Jørgensen
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Gregory Druschel
- Department of Earth Sciences, Indiana University-Purdue University, Indianapolis, Indiana, USA
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tübingen, Germany
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22
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Patzner M, Kainz N, Lundin E, Barczok M, Smith C, Herndon E, Kinsman-Costello L, Fischer S, Straub D, Kleindienst S, Kappler A, Bryce C. Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4620-4631. [PMID: 35290040 PMCID: PMC9097474 DOI: 10.1021/acs.est.1c06937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO2 and CH4. During the summer, shifts in runoff and soil moisture influence redox conditions and therefore the balance of Fe oxidation and reduction. Whether reactive iron minerals could act as a stable sink for carbon or whether they are continuously dissolved and reprecipitated during redox shifts remains unknown. We deployed bags of synthetic ferrihydrite (FH)-coated sand in the active layer along a permafrost thaw gradient in Stordalen mire (Abisko, Sweden) over the summer (June to September) to capture changes in redox conditions and quantify the formation and dissolution of reactive Fe(III) (oxyhydr)oxides. We found that the bags accumulated Fe(III) under constant oxic conditions in areas overlying intact permafrost over the full summer season. In contrast, in fully thawed areas, conditions were continuously anoxic, and by late summer, 50.4 ± 12.8% of the original Fe(III) (oxyhydr)oxides were lost via dissolution. Periodic redox shifts (from 0 to +300 mV) were observed over the summer season in the partially thawed areas. This resulted in the dissolution and loss of 47.2 ± 20.3% of initial Fe(III) (oxyhydr)oxides when conditions are wetter and more reduced, and new formation of Fe(III) minerals (33.7 ± 8.6% gain in comparison to initial Fe) in the late summer under more dry and oxic conditions, which also led to the sequestration of Fe-bound organic carbon. Our data suggest that there is seasonal turnover of iron minerals in partially thawed permafrost peatlands, but that a fraction of the Fe pool remains stable even under continuously anoxic conditions.
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Affiliation(s)
- Monique
S. Patzner
- Geomicrobiology,
Center for Applied Geosciences, University
of Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Nora Kainz
- Geomicrobiology,
Center for Applied Geosciences, University
of Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Erik Lundin
- Abisko
Scientific Research Station, Swedish Polar
Research Secretariat, Vetenskapens väg 38, SE-891
07 Abisko, Sweden
| | - Maximilian Barczok
- Department
of Geology, Kent State University, Kent, Ohio 44242, United States
| | - Chelsea Smith
- Department
of Biological Sciences, Kent State University, Kent, Ohio 44242, United States
| | - Elizabeth Herndon
- Environmental
Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States
| | | | - Stefan Fischer
- Tuebingen
Structural Microscopy Core Facility, Center for Applied Geosciences, University Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Daniel Straub
- Microbial
Ecology, Center for Applied Geosciences, University Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
- Quantitative
Biology Center (QBiC), University Tuebingen, Auf der Morgenstelle 10, 72076 Tuebingen, Germany
| | - Sara Kleindienst
- Microbial
Ecology, Center for Applied Geosciences, University Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Andreas Kappler
- Geomicrobiology,
Center for Applied Geosciences, University
of Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
- Cluster
of Excellence: EXC 2124: Controlling Microbes to Fight Infection, 72074 Tübingen, Germany
| | - Casey Bryce
- School
of Earth Sciences, University of Bristol, Bristol BS8 1RJ, U.K.
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23
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Photoferrotrophy and phototrophic extracellular electron uptake is common in the marine anoxygenic phototroph Rhodovulum sulfidophilum. THE ISME JOURNAL 2021; 15:3384-3398. [PMID: 34054125 PMCID: PMC8528915 DOI: 10.1038/s41396-021-01015-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/07/2021] [Accepted: 05/12/2021] [Indexed: 02/03/2023]
Abstract
Photoferrotrophy allows anoxygenic phototrophs to use reduced iron as an electron donor for primary productivity. Recent work shows that freshwater photoferrotrophs can use electrons from solid-phase conductive substances via phototrophic extracellular electron uptake (pEEU), and the two processes share the underlying electron uptake mechanism. However, the ability of marine phototrophs to perform photoferrotrophy and pEEU, and the contribution of these processes to primary productivity is largely unknown. To fill this knowledge gap, we isolated 15 new strains of the marine anoxygenic phototroph Rhodovulum sulfidophilum on electron donors such as acetate and thiosulfate. We observed that all of the R. sulfidophilum strains isolated can perform photoferrotrophy. We chose strain AB26 as a representative strain to study further, and find that it can also perform pEEU from poised electrodes. We show that during pEEU, AB26 transfers electrons to the photosynthetic electron transport chain. Furthermore, systems biology-guided mutant analysis shows that R. sulfidophilum AB26 uses a previously unknown diheme cytochrome c protein, which we call EeuP, for pEEU but not photoferrotrophy. Homologs of EeuP occur in a range of widely distributed marine microbes. Overall, these results suggest that photoferrotrophy and pEEU contribute to the biogeochemical cycling of iron and carbon in marine ecosystems.
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24
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Zhan Y, Yang M, Zhang Y, Yang J, Wang W, Yan L, Zhang S. Iron and total organic carbon shape the spatial distribution pattern of sediment Fe(III) reducing bacteria in a volcanic lake, NE China. World J Microbiol Biotechnol 2021; 37:155. [PMID: 34398324 DOI: 10.1007/s11274-021-03125-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/11/2021] [Indexed: 11/28/2022]
Abstract
Fe(III) reducing bacteria (FeRB) play a vital role in the biogeochemical cycle of Fe, C and N in nature. The volcanic lake can be considered as an ideal habitat for FeRB. Here, we investigated the diversity and spatial distribution of FeRB in sediments of Wenbo lake in Wudalianchi volcano based on culture-dependent and independent methods. A total of 28 isolates affiliated with the genera of Enterobacter, Bacillus, Pseudomonas and Clostridium were obtained from 18 sediment samples. We detected 783 operational taxonomic units (OTUs) belonged to FeRB using high high-throughput sequencing, and the dominant phyla were Proteobacteria (3.65%), Acidobacteria (0.29%), Firmicutes (10.78%). The representative FeRB genera such as Geobacter, Pseudomonas, Thiobacillus and Acinetobacter distributed widely in Wenbo lake. Results showed that the diversity and abundance of FeRB declined along the water-flow direction from Libo to Jingbo. In contrast, the FeRB diversity decreased and the FeRB abundance increased along with depth transect of sediments. It was found that the dominant phylum changed from Firmicutes to Proteobacteria along the water-flow direction, while changed from Proteobacteria to Firmicutes along with the depth of sediments. RDA indicated that the FeRB distribution were driven by soluble total iron, total organic carbon, Fe(II) and Fe(III). These will provide information for understanding the role of FeRB in the elements geochemical cycles in the volcanic environment.
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Affiliation(s)
- Yue Zhan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China.,Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A & F University, Yangling, 712100, Shaanxi, People's Republic of China
| | - Mengran Yang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China
| | - Yu Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China
| | - Jian Yang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China
| | - Weidong Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China
| | - Lei Yan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China.
| | - Shuang Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, 163319, People's Republic of China.
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25
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Liu X, Huang L, Rensing C, Ye J, Nealson KH, Zhou S. Syntrophic interspecies electron transfer drives carbon fixation and growth by Rhodopseudomonas palustris under dark, anoxic conditions. SCIENCE ADVANCES 2021; 7:eabh1852. [PMID: 34215588 PMCID: PMC11057707 DOI: 10.1126/sciadv.abh1852] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
In natural anoxic environments, anoxygenic photosynthetic bacteria fix CO2 by photoheterotrophy, photoautotrophy, or syntrophic anaerobic photosynthesis. Here, we describe electroautotrophy, a previously unidentified dark CO2 fixation mode enabled by the electrosyntrophic interaction between Geobacter metallireducens and Rhodopseudomonas palustris. After an electrosyntrophic coculture is formed, electrons are transferred either directly or indirectly (via electron shuttles) from G. metallireducens to R. palustris, thereby providing reducing power and energy for the dark CO2 fixation. Transcriptomic analyses demonstrated the high expression of genes encoding for the extracellular electron transfer pathway in G. metallireducens and the Calvin-Benson-Bassham carbon fixation cycle in R. palustris Given that sediments constitute one of the most ubiquitous and abundant niches on Earth and that, at depth, most of the sedimentary niche is both anoxic and dark, dark carbon fixation provides a metabolic window for the survival of anoxygenic phototrophs, as well as an as-yet unappreciated contribution to the global carbon cycle.
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Affiliation(s)
- Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lingyan Huang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jie Ye
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kenneth H Nealson
- Department of Earth Science, University of Southern California, Los Angeles, CA, USA.
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.
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26
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Huang J, Jones A, Waite TD, Chen Y, Huang X, Rosso KM, Kappler A, Mansor M, Tratnyek PG, Zhang H. Fe(II) Redox Chemistry in the Environment. Chem Rev 2021; 121:8161-8233. [PMID: 34143612 DOI: 10.1021/acs.chemrev.0c01286] [Citation(s) in RCA: 166] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Iron (Fe) is the fourth most abundant element in the earth's crust and plays important roles in both biological and chemical processes. The redox reactivity of various Fe(II) forms has gained increasing attention over recent decades in the areas of (bio) geochemistry, environmental chemistry and engineering, and material sciences. The goal of this paper is to review these recent advances and the current state of knowledge of Fe(II) redox chemistry in the environment. Specifically, this comprehensive review focuses on the redox reactivity of four types of Fe(II) species including aqueous Fe(II), Fe(II) complexed with ligands, minerals bearing structural Fe(II), and sorbed Fe(II) on mineral oxide surfaces. The formation pathways, factors governing the reactivity, insights into potential mechanisms, reactivity comparison, and characterization techniques are discussed with reference to the most recent breakthroughs in this field where possible. We also cover the roles of these Fe(II) species in environmental applications of zerovalent iron, microbial processes, biogeochemical cycling of carbon and nutrients, and their abiotic oxidation related processes in natural and engineered systems.
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Affiliation(s)
- Jianzhi Huang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Adele Jones
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yiling Chen
- Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaopeng Huang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kevin M Rosso
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Muammar Mansor
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Paul G Tratnyek
- School of Public Health, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
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27
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Tong H, Chen M, Lv Y, Liu C, Zheng C, Xia Y. Changes in the microbial community during microbial microaerophilic Fe(II) oxidation at circumneutral pH enriched from paddy soil. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2021; 43:1305-1317. [PMID: 32975698 DOI: 10.1007/s10653-020-00725-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
Fe(II)-oxidizing bacteria (FeOB) are important catalysts for iron cycling in iron-rich marine, groundwater, and freshwater environments. However, few studies have reported the distribution and diversity of these bacteria in flooded paddy soils. This study investigates the microbial structure and diversity of microaerophilic Fe(II)-oxidizing bacteria (mFeOB) and their possible role in Fe(II) oxidation in iron-rich paddy soils. Using enrichment experiments that employed serial transfers, the changes in microaerophilic microbial community were examined via 16S rRNA gene high-throughput sequencing. During enrichments, the Fe(II) oxidation rate decreased as transfers increased, and the maximum rate of Fe(II) oxidation was observed in the first transfer (0.197 mM day-1). Results from X-ray diffraction of minerals and scanning electron microscopy of the cell-mineral aggregates revealed that cell surfaces in all transfers were partly covered with amorphous iron oxide formed by FeOB. After four transfers, the phyla of Proteobacteria had a dominant presence that reached up to 95%. Compared with the original soil, the relative abundances of Cupriavidus, Massilia, Pseudomonas, Ralstonia, Sphingomonas, and Variovorax increased in FeS gradient tubes and became dominant genera after transfers. Cupriavidus, Pseudomonas, and Ralstonia have been identified as FeOB previously. Furthermore, the structure of the microbial community tended to be stable as transfers increased, indicating that other bacterial species might perform important roles in Fe(II) oxidation. These results suggest the potential involvement of mFeOB and these other microorganisms in the Fe(II)-oxidizing process of soils. It will be helpful for future studies to consider their role in related biogeochemical processes, such as transformation of organic matters and heavy metals.
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Affiliation(s)
- Hui Tong
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science and Technology, Guangdong Academy of Sciences, Guangzhou, 510650, China
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Manjia Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science and Technology, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Yahui Lv
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environmental Science and Technology, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Chengshuai Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
- CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China.
| | - Chunju Zheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Yafei Xia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
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28
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Discovering symbiosis in the supralittoral: bacterial metabarcoding analysis from the hepatopancreas of Orchestia and Tylos (Crustacea). Symbiosis 2021. [DOI: 10.1007/s13199-021-00749-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Pandey CB, Kumar U, Kaviraj M, Minick KJ, Mishra AK, Singh JS. DNRA: A short-circuit in biological N-cycling to conserve nitrogen in terrestrial ecosystems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 738:139710. [PMID: 32544704 DOI: 10.1016/j.scitotenv.2020.139710] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
This paper reviews dissimilatory nitrate reduction to ammonium (DNRA) in soils - a newly appreciated pathway of nitrogen (N) cycling in the terrestrial ecosystems. The reduction of NO3- occurs in two steps; in the first step, NO3- is reduced to NO2-; and in the second, unlike denitrification, NO2- is reduced to NH4+ without intermediates. There are two sets of NO3-/NO2- reductase enzymes, i.e., Nap/Nrf and Nar/Nir; the former occurs on the periplasmic-membrane and energy conservation is respiratory via electron-transport-chain, whereas the latter is cytoplasmic and energy conservation is both respiratory and fermentative (Nir, substrate-phosphorylation). Since, Nir catalyzes both assimilatory- and dissimilatory-nitrate reduction, the nrfA gene, which transcribes the NrfA protein, is treated as a molecular-marker of DNRA; and a high nrfA/nosZ (N2O-reductase) ratio favours DNRA. Recently, several crystal structures of NrfA have been presumed to producee N2O as a byproduct of DNRA via the NO (nitric-oxide) pathway. Meta-analyses of about 200 publications have revealed that DNRA is regulated by oxidation state of soils and sediments, carbon (C)/N and NO2-/NO3- ratio, and concentrations of ferrous iron (Fe2+) and sulfide (S2-). Under low-redox conditions, a high C/NO3- ratio selects for DNRA while a low ratio selects for denitrification. When the proportion of both C and NO3- are equal, the NO2-/NO3- ratio modulates partitioning of NO3-, and a high NO2-/NO3- ratio favours DNRA. A high S2-/NO3- ratio also promotes DNRA in coastal-ecosystems and saline sediments. Soil pH, temperature, and fine soil particles are other factors known to influence DNRA. Since, DNRA reduces NO3- to NH4+, it is essential for protecting NO3- from leaching and gaseous (N2O) losses and enriches soils with readily available NH4+-N to primary producers and heterotrophic microorganisms. Therefore, DNRA may be treated as a tool to reduce ground-water NO3- pollution, enhance soil health and improve environmental quality.
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Affiliation(s)
- C B Pandey
- ICAR-Central Arid Zone Research Institute, Jodhpur 342003, Rajasthan, India.
| | - Upendra Kumar
- ICAR-National Rice Research Institute, Cuttack 753006, Odisha, India.
| | - Megha Kaviraj
- ICAR-National Rice Research Institute, Cuttack 753006, Odisha, India
| | - K J Minick
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA
| | - A K Mishra
- International Rice Research Institute, New Delhi 110012, India
| | - J S Singh
- Ecosystem Analysis Lab, Centre of Advanced Study in Botany, Banaras Hindu University (BHU), Varanasi 221005, India
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30
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Genomic Insights into Two Novel Fe(II)-Oxidizing Zetaproteobacteria Isolates Reveal Lifestyle Adaption to Coastal Marine Sediments. Appl Environ Microbiol 2020; 86:AEM.01160-20. [PMID: 32561582 DOI: 10.1128/aem.01160-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/13/2020] [Indexed: 11/20/2022] Open
Abstract
The discovery of the novel Zetaproteobacteria class greatly expanded our understanding of neutrophilic, microaerophilic microbial Fe(II) oxidation in marine environments. Despite molecular techniques demonstrating their global distribution, relatively few isolates exist, especially from low-Fe(II) environments. Furthermore, the Fe(II) oxidation pathways used by Zetaproteobacteria remain poorly understood. Here, we present the genomes (>99% genome completeness) of two Zetaproteobacteria, which are the only cultivated isolates originating from typical low-Fe [porewater Fe(II), 70 to 100 μM] coastal marine sediments. The two strains share <90% average nucleotide identity (ANI) with each other and <80% ANI with any other Zetaproteobacteria genome. The closest relatives were Mariprofundus aestuarium strain CP-5 and Mariprofundus ferrinatatus strain CP-8 (96 to 98% 16S rRNA gene sequence similarity). Fe(II) oxidation of strains KV and NF is most likely mediated by the putative Fe(II) oxidase Cyc2. Interestingly, the genome of strain KV also encodes a putative multicopper oxidase, PcoAB, which could play a role in Fe(II) oxidation, a pathway found only in two other Zetaproteobacteria genomes (Ghiorsea bivora TAG-1 and SCGC AB-602-C20). The strains show potential adaptations to fluctuating O2 concentrations, indicated by the presence of both cbb 3- and aa 3-type cytochrome c oxidases, which are adapted to low and high O2 concentrations, respectively. This is further supported by the presence of several oxidative-stress-related genes. In summary, our results reveal the potential Fe(II) oxidation pathways employed by these two novel chemolithoautotrophic Fe(II)-oxidizing species and the lifestyle adaptations which enable the Zetaproteobacteria to survive in coastal environments with low Fe(II) and regular redox fluctuations.IMPORTANCE Until recently, the importance and relevance of Zetaproteobacteria were mainly thought to be restricted to high-Fe(II) environments, such as deep-sea hydrothermal vents. The two novel Mariprofundus isolates presented here originate from typical low-Fe(II) coastal marine sediments. As well as being low in Fe(II), these environments are often subjected to fluctuating O2 concentrations and regular mixing by wave action and bioturbation. The discovery of two novel isolates highlights the importance of these organisms in such environments, as Fe(II) oxidation has been shown to impact nutrients and trace metals. Genome analysis of these two strains further supported their lifestyle adaptation and therefore their potential preference for coastal marine sediments, as genes necessary for surviving dynamic O2 concentrations and oxidative stress were identified. Furthermore, our analyses also expand our understanding of the poorly understood Fe(II) oxidation pathways used by neutrophilic, microaerophilic Fe(II) oxidizers.
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31
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Geelhoed JS, van de Velde SJ, Meysman FJR. Quantification of Cable Bacteria in Marine Sediments via qPCR. Front Microbiol 2020; 11:1506. [PMID: 32719667 PMCID: PMC7348212 DOI: 10.3389/fmicb.2020.01506] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/10/2020] [Indexed: 11/13/2022] Open
Abstract
Cable bacteria (Deltaproteobacteria, Desulfobulbaceae) are long filamentous sulfur-oxidizing bacteria that generate long-distance electric currents running through the bacterial filaments. This way, they couple the oxidation of sulfide in deeper sediment layers to the reduction of oxygen or nitrate near the sediment-water interface. Cable bacteria are found in a wide range of aquatic sediments, but an accurate procedure to assess their abundance is lacking. We developed a qPCR approach that quantifies cable bacteria in relation to other bacteria within the family Desulfobulbaceae. Primer sets targeting cable bacteria, Desulfobulbaceae and the total bacterial community were applied in qPCR with DNA extracted from marine sediment incubations. Amplicon sequencing of the 16S rRNA gene V4 region confirmed that cable bacteria were accurately enumerated by qPCR, and suggested novel diversity of cable bacteria. The conjoint quantification of current densities and cell densities revealed that individual filaments carry a mean current of ∼110 pA and have a cell specific oxygen consumption rate of 69 fmol O2 cell–1 day–1. Overall, the qPCR method enables a better quantitative assessment of cable bacteria abundance, providing new metabolic insights at filament and cell level, and improving our understanding of the microbial ecology of electrogenic sediments.
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Affiliation(s)
| | - Sebastiaan J van de Velde
- Department of Earth and Planetary Sciences, University of California, Riverside, Riverside, CA, United States
| | - Filip J R Meysman
- Department of Biology, University of Antwerp, Antwerp, Belgium.,Department of Biotechnology, Delft University of Technology, Delft, Netherlands
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32
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Lueder U, Maisch M, Laufer K, Jo Rgensen BB, Kappler A, Schmidt C. Influence of Physical Perturbation on Fe(II) Supply in Coastal Marine Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3209-3218. [PMID: 32064861 DOI: 10.1021/acs.est.9b06278] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Iron (Fe) biogeochemistry in marine sediments is driven by redox transformations creating Fe(II) and Fe(III) gradients. As sediments are physically mixed by wave action or bioturbation, Fe gradients re-establish regularly. In order to identify the response of dissolved Fe(II) (Fe2+) and Fe mineral phases toward mixing processes, we performed voltammetric microsensor measurements, sequential Fe extractions, and Mössbauer spectroscopy of 12 h light-dark cycle incubated marine coastal sediment. Fe2+ decreased during 7 days of undisturbed incubation from approximately 400 to 60 μM. In the first 2-4 days of incubation, Fe2+ accumulated up to 100 μM in the top 2 mm due to Fe(III) photoreduction. After physical perturbation at day 7, Fe2+ was re-mobilized reaching concentrations of 320 μM in 30 mm depth, which decreased to below detection limit within 2 days afterward. Mössbauer spectroscopy showed that the relative abundance of metastable iron-sulfur mineral phases (FeSx) increased during initial incubation and decreased together with pyrite (FeS2) after perturbation. We show that Fe2+ mobilization in marine sediments is stimulated by chemical changes caused by physical disturbances impacting the Fe redox distribution. Our study suggests that, in addition to microbial and abiotic Fe(III) reduction, including Fe(III) photoreduction, physical mixing processes induce chemical changes providing sediments and the inhabiting microbial community with Fe2+.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
| | - Markus Maisch
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
| | - Katja Laufer
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
- GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany
| | - Bo Barker Jo Rgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
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Lueder U, Jørgensen BB, Kappler A, Schmidt C. Fe(III) Photoreduction Producing Fe aq2+ in Oxic Freshwater Sediment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:862-869. [PMID: 31886652 DOI: 10.1021/acs.est.9b05682] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Iron(III) (Fe(III)) photoreduction plays an important role in Fe cycling and Fe(II) bioavailability in the upper ocean. Although well described for water columns, it is currently unknown to what extent light impacts the production of dissolved Fe(II) (Fe2+) in aquatic sediments. We performed high-resolution voltammetric microsensor measurements and demonstrated light-induced Fe2+ release in freshwater sediments from Lake Constance. Fe2+ concentrations increased up to 40 μM in the top 3 mm of the sediment during illumination in the visible range of light (400-700 nm), even in the presence of oxygen (100-280 μM). The Fe2+ release was strongly dependent on the organic matter content of the sediment. A lack of photoreduced Fe2+ was measured in sediments with concentrations of organic carbon <6 mg L-1. The simultaneous presence of sedimentary Fe(III) photoreduction besides microbial and abiotic Fe2+ oxidation by oxygen suggests an active Fe redox cycling in the oxic and photic zone of aquatic sediments. Here, we provide evidence for a relevant contribution of Fe(III) photoreduction to the bio-geochemical Fe redox cycle in aquatic freshwater sediments.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG) , University of Tuebingen , Sigwartstrasse 10 , D-72076 Tuebingen , Germany
| | - Bo Barker Jørgensen
- Center for Geomicrobiology, Department of Bioscience , Aarhus University , Ny Munkegade 114, Building 1540 , 8000 Aarhus , Denmark
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG) , University of Tuebingen , Sigwartstrasse 10 , D-72076 Tuebingen , Germany
- Center for Geomicrobiology, Department of Bioscience , Aarhus University , Ny Munkegade 114, Building 1540 , 8000 Aarhus , Denmark
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG) , University of Tuebingen , Sigwartstrasse 10 , D-72076 Tuebingen , Germany
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Lueder U, Jørgensen BB, Kappler A, Schmidt C. Photochemistry of iron in aquatic environments. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:12-24. [PMID: 31904051 DOI: 10.1039/c9em00415g] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Light energy is a driver for many biogeochemical element cycles in aquatic systems. The sunlight-induced photochemical reduction of ferric iron (Fe(iii) photoreduction) to ferrous iron (Fe(ii)) by either direct ligand-to-metal charge transfer or by photochemically produced radicals can be an important source of dissolved Feaq2+ in aqueous and sedimentary environments. Reactive oxygen species (ROS) are formed by a variety of light-dependent reactions. Those ROS can oxidize Fe(ii) or reduce Fe(iii), and due to their high reactivity they are key oxidants in aquatic systems where they influence many other biogeochemical cycles. In oxic waters with circumneutral pH, the produced Fe(ii) reaches nanomolar concentrations and serves as a nutrient, whereas in acidic waters, freshwater and marine sediments, which are rich in Fe(ii), the photochemically formed Fe(ii) can reach concentrations of up to 100 micromolar and be used as additional electron donor for acidophilic aerobic, microaerophilic, phototrophic and, if nitrate is present, for nitrate-reducing Fe(ii)-oxidizing bacteria. Therefore, Fe(iii) photoreduction may not only control the primary productivity in the oceans but has a tremendous impact on Fe cycling in the littoral zone of freshwater and marine environments. In this review, we summarize photochemical reactions involving Fe, discuss the role of ROS in Fe cycling, and highlight the importance of photoreductive processes in the environment.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany.
| | - Bo Barker Jørgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany. and Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany.
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Gupta D, Sutherland MC, Rengasamy K, Meacham JM, Kranz RG, Bose A. Photoferrotrophs Produce a PioAB Electron Conduit for Extracellular Electron Uptake. mBio 2019; 10:e02668-19. [PMID: 31690680 PMCID: PMC6831781 DOI: 10.1128/mbio.02668-19] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 10/10/2019] [Indexed: 11/20/2022] Open
Abstract
Photoferrotrophy is a form of anoxygenic photosynthesis whereby bacteria utilize soluble or insoluble forms of ferrous iron as an electron donor to fix carbon dioxide using light energy. They can also use poised electrodes as their electron donor via phototrophic extracellular electron uptake (phototrophic EEU). The electron uptake mechanisms underlying these processes are not well understood. Using Rhodopseudomonas palustris TIE-1 as a model, we show that a single periplasmic decaheme cytochrome c, PioA, and an outer membrane porin, PioB, form a complex allowing extracellular electron uptake across the outer membrane from both soluble iron and poised electrodes. We observe that PioA undergoes postsecretory proteolysis of its N terminus to produce a shorter heme-attached PioA (holo-PioAC, where PioAC represents the C terminus of PioA), which can exist both freely in the periplasm and in a complex with PioB. The extended N-terminal peptide controls heme attachment, and its processing is required to produce wild-type levels of holo-PioAC and holo-PioACB complex. It is also conserved in PioA homologs from other phototrophs. The presence of PioAB in these organisms correlate with their ability to perform photoferrotrophy and phototrophic EEU.IMPORTANCE Some anoxygenic phototrophs use soluble iron, insoluble iron minerals (such as rust), or their proxies (poised electrodes) as electron donors for photosynthesis. However, the underlying electron uptake mechanisms are not well established. Here, we show that these phototrophs use a protein complex made of an outer membrane porin and a periplasmic decaheme cytochrome (electron transfer protein) to harvest electrons from both soluble iron and poised electrodes. This complex has two unique characteristics: (i) it lacks an extracellular cytochrome c, and (ii) the periplasmic decaheme cytochrome c undergoes proteolytic cleavage to produce a functional electron transfer protein. These characteristics are conserved in phototrophs harboring homologous proteins.
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Affiliation(s)
- Dinesh Gupta
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Molly C Sutherland
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - J Mark Meacham
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA
- Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Robert G Kranz
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Arpita Bose
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
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Otte JM, Blackwell N, Ruser R, Kappler A, Kleindienst S, Schmidt C. N 2O formation by nitrite-induced (chemo)denitrification in coastal marine sediment. Sci Rep 2019; 9:10691. [PMID: 31366952 PMCID: PMC6668465 DOI: 10.1038/s41598-019-47172-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 07/12/2019] [Indexed: 11/08/2022] Open
Abstract
Nitrous oxide (N2O) is a potent greenhouse gas that also contributes to stratospheric ozone depletion. Besides microbial denitrification, abiotic nitrite reduction by Fe(II) (chemodenitrification) has the potential to be an important source of N2O. Here, using microcosms, we quantified N2O formation in coastal marine sediments under typical summer temperatures. Comparison between gamma-radiated and microbially-active microcosm experiments revealed that at least 15-25% of total N2O formation was caused by chemodenitrification, whereas 75-85% of total N2O was potentially produced by microbial N-transformation processes. An increase in (chemo)denitrification-based N2O formation and associated Fe(II) oxidation caused an upregulation of N2O reductase (typical nosZ) genes and a distinct community shift to potential Fe(III)-reducers (Arcobacter), Fe(II)-oxidizers (Sulfurimonas), and nitrate/nitrite-reducing microorganisms (Marinobacter). Our study suggests that chemodenitrification contributes substantially to N2O formation from marine sediments and significantly influences the N- and Fe-cycling microbial community.
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Affiliation(s)
- Julia M Otte
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
- Microbial Ecology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
| | - Nia Blackwell
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
- Microbial Ecology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
| | - Reiner Ruser
- Fertilization and Soil Matter Dynamics, Institute of Crop Science, University of Hohenheim, Stuttgart, Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany.
- Center for Geomicrobiology, Aarhus University, Aarhus, Denmark.
| | - Sara Kleindienst
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
- Microbial Ecology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
| | - Caroline Schmidt
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
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Maisch M, Lueder U, Laufer K, Scholze C, Kappler A, Schmidt C. Contribution of Microaerophilic Iron(II)-Oxidizers to Iron(III) Mineral Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8197-8204. [PMID: 31203607 DOI: 10.1021/acs.est.9b01531] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neutrophilic microbial aerobic oxidation of ferrous iron (Fe(II)) is restricted to pH-circumneutral environments characterized by low oxygen where microaerophilic Fe(II)-oxidizing microorganisms successfully compete with abiotic Fe(II) oxidation. However, accumulation of ferric (bio)minerals increases competition by stimulating abiotic surface-catalyzed heterogeneous Fe(II) oxidation. Here, we present an experimental approach that allows quantification of microbial and abiotic contribution to Fe(II) oxidation in the presence or initial absence of ferric (bio)minerals. We found that at 20 μM O2 and the initial absence of Fe(III) minerals, an iron(II)-oxidizing enrichment culture (99.6% similarity to Sideroxydans spp.) contributed 40% to the overall Fe(II) oxidation within approximately 26 h and oxidized up to 3.6 × 10-15 mol Fe(II) cell-1 h-1. Optimum O2 concentrations at which enzymatic Fe(II) oxidation can compete with abiotic Fe(II) oxidation ranged from 5 to 20 μM. Lower O2 levels limited biotic Fe(II) oxidation, while at higher O2 levels abiotic Fe(II) oxidation dominated. The presence of ferric (bio)minerals induced surface-catalytic heterogeneous abiotic Fe(II) oxidation and reduced the microbial contribution to Fe(II) oxidation from 40% to 10% at 10 μM O2. The obtained results will help to better assess the impact of microaerophilic Fe(II) oxidation on the biogeochemical iron cycle in a variety of environmental natural and anthropogenic settings.
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Affiliation(s)
- Markus Maisch
- Geomicrobiology, Center for Applied Geosciences , University of Tübingen , Tübingen 72074 , Germany
| | - Ulf Lueder
- Geomicrobiology, Center for Applied Geosciences , University of Tübingen , Tübingen 72074 , Germany
| | - Katja Laufer
- Department for Bioscience , Aarhus University , 8000 Aarhus , Denmark
| | - Caroline Scholze
- Department for Bioscience , Aarhus University , 8000 Aarhus , Denmark
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences , University of Tübingen , Tübingen 72074 , Germany
- Department for Bioscience , Aarhus University , 8000 Aarhus , Denmark
| | - Caroline Schmidt
- Geomicrobiology, Center for Applied Geosciences , University of Tübingen , Tübingen 72074 , Germany
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Complex Microbial Communities Drive Iron and Sulfur Cycling in Arctic Fjord Sediments. Appl Environ Microbiol 2019; 85:AEM.00949-19. [PMID: 31076435 DOI: 10.1128/aem.00949-19] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 04/28/2019] [Indexed: 11/20/2022] Open
Abstract
Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in low-organic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20 cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducing Desulfuromonadales, iron-oxidizing Gallionella and Mariprofundus, and sulfur-oxidizing Thiotrichales and Epsilonproteobacteria were abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducing Desulfobacteraceae and Desulfobulbaceae increased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (∼5 cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by δ13C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron- and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf.IMPORTANCE Glacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.
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Novotnik B, Zorz J, Bryant S, Strous M. The Effect of Dissimilatory Manganese Reduction on Lactate Fermentation and Microbial Community Assembly. Front Microbiol 2019; 10:1007. [PMID: 31156573 PMCID: PMC6531920 DOI: 10.3389/fmicb.2019.01007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 04/18/2019] [Indexed: 12/30/2022] Open
Abstract
Fermentation and dissimilatory manganese (Mn) reduction are inter-related metabolic processes that microbes can perform in anoxic environments. Fermentation is less energetically favorable and is often not considered to compete for organic carbon with dissimilatory metal reduction. Therefore, the aim of our study was to investigate the outcome of the competition for lactate between fermentation and Mn oxide (birnessite) reduction in a mixed microbial community. A birnessite reducing enrichment culture was obtained from activated sludge with lactate and birnessite as the substrates. This enrichment was further used to test how various birnessite activities (0, 10, 20, and 40 mM) affected the rates of fermentation and metal reduction, as well as community composition. Increased birnessite activity led to a decrease of lactate consumption rate. Acetate and propionate were the main products. With increasing birnessite activity, the propionate/acetate ratio decreased from 1.4 to 0.47. Significant CO2 production was detected only in the absence of birnessite. In its presence, CO2 concentrations remained close to the background since most of the CO2 produced in these experiments was recovered as MnCO3. The Mn reduction efficiency (Mn(II) produced divided by birnessite added) was the highest at 10 mM birnessite added, where about 50% of added birnessite was reduced to Mn(II), whereas at 20 and 40 mM approximately 21 and 16% was reduced. The decreased birnessite reduction efficiency at higher birnessite activities points to inhibition by terminal electron acceptors and/or its toxicity which was also indicated by retarded lactate oxidation and decreased concentrations of microbial metabolites. Birnessite activity strongly affected microbial community structure. Firmicutes and Bacteroidetes were the most abundant phyla at 0 mM of birnessite. Their abundance was inversely correlated with birnessite concentration. The relative sequence abundance of Proteobacteria correlated with birnessite concentrations. Most of the enriched populations were involved in lactate/acetate or amino acid fermentation and the only previously known metal reducing genus detected was related to Shewanella sp. The sequencing data confirmed that lactate consumption coupled to metal reduction was only one of the processes occurring and did not outcompete fermentation processes.
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Affiliation(s)
- Breda Novotnik
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Jackie Zorz
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
| | - Steven Bryant
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, Canada
| | - Marc Strous
- Department of Geoscience, University of Calgary, Calgary, AB, Canada
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Yang CL, Chen XK, Wang R, Lin JQ, Liu XM, Pang X, Zhang CJ, Lin JQ, Chen LX. Essential Role of σ Factor RpoF in Flagellar Biosynthesis and Flagella-Mediated Motility of Acidithiobacillus caldus. Front Microbiol 2019; 10:1130. [PMID: 31178842 PMCID: PMC6543871 DOI: 10.3389/fmicb.2019.01130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/03/2019] [Indexed: 12/04/2022] Open
Abstract
Acidithiobacillaceae, an important family of acidophilic and chemoautotrophic sulfur or iron oxidizers, participate in geobiochemical circulation of the elements and drive the release of heavy metals in mining associated habitats. Because of their environmental adaptability and energy metabolic systems, Acidithiobacillus spp. have become the dominant bacteria used in bioleaching for heavy metal recovery. Flagella-driven motility is associated with bacterial chemotaxis and bacterial responses to environmental stimuli. However, little is known about how the flagellum of Acidithiobacillus spp. is regulated and how the flagellum affects the growth of these chemoautotrophic bacteria. In this study, we analyzed the flagellar gene clusters in Acidithiobacillus strains and uncovered the close relationship between flagella and the sulfur-oxidizing systems (Sox system). The σ28 gene (rpoF) knockout and overexpression strains of Acidithiobacillus caldus were constructed. Scanning electron microscopy shows that A. caldus ΔrpoF cells lacked flagella, indicating the essential role of RpoF in regulating flagella synthesis in these chemoautotrophic bacteria. Motility analysis suggests that the deletion of rpoF resulted in the reduction of swarming capability, while this capability was enhanced in the rpoF overexpression strain. Both static cultivation and low concentration of energy substrates (elemental sulfur or tetrathionate) led to weak growth of A. caldus ΔrpoF cells. The deletion of rpoF promoted bacterial attachment to the surface of elemental sulfur in static cultivation. The absence of RpoF caused an obvious change in transcription profile, including genes in flagellar cluster and those involved in biofilm formation. These results provide an understanding on the regulation of flagellar hierarchy and the flagellar function in these sulfur or iron oxidizers.
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Affiliation(s)
- Chun-Long Yang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xian-Ke Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Rui Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jian-Qiang Lin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xiang-Mei Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xin Pang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Cheng-Jia Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Jian-Qun Lin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Lin-Xu Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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Peng C, Bryce C, Sundman A, Kappler A. Cryptic Cycling of Complexes Containing Fe(III) and Organic Matter by Phototrophic Fe(II)-Oxidizing Bacteria. Appl Environ Microbiol 2019; 85:e02826-18. [PMID: 30796062 PMCID: PMC6450027 DOI: 10.1128/aem.02826-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 02/14/2019] [Indexed: 11/20/2022] Open
Abstract
Fe-organic matter (Fe-OM) complexes are abundant in the environment and, due to their mobility, reactivity, and bioavailability, play a significant role in the biogeochemical Fe cycle. In photic zones of aquatic environments, Fe-OM complexes can potentially be reduced and oxidized, and thus cycled, by light-dependent processes, including abiotic photoreduction of Fe(III)-OM complexes and microbial oxidation of Fe(II)-OM complexes, by anoxygenic phototrophic bacteria. This could lead to a cryptic iron cycle in which continuous oxidation and rereduction of Fe could result in a low and steady-state Fe(II) concentration despite rapid Fe turnover. However, the coupling of these processes has never been demonstrated experimentally. In this study, we grew a model anoxygenic phototrophic Fe(II) oxidizer, Rhodobacter ferrooxidans SW2, with either citrate, Fe(II)-citrate, or Fe(III)-citrate. We found that strain SW2 was capable of reoxidizing Fe(II)-citrate produced by photochemical reduction of Fe(III)-citrate, which kept the dissolved Fe(II)-citrate concentration at low (<10 μM) and stable concentrations, with a concomitant increase in cell numbers. Cell suspension incubations with strain SW2 showed that it can also oxidize Fe(II)-EDTA, Fe(II)-humic acid, and Fe(II)-fulvic acid complexes. This work demonstrates the potential for active cryptic Fe cycling in the photic zone of anoxic aquatic environments, despite low measurable Fe(II) concentrations which are controlled by the rate of microbial Fe(II) oxidation and the identity of the Fe-OM complexes.IMPORTANCE Iron cycling, including reduction of Fe(III) and oxidation of Fe(II), involves the formation, transformation, and dissolution of minerals and dissolved iron-organic matter compounds. It has been shown previously that Fe can be cycled so rapidly that no measurable changes in Fe(II) and Fe(III) concentrations occur, leading to a so-called cryptic cycle. Cryptic Fe cycles have been shown to be driven either abiotically by a combination of photochemical reduction of Fe(III)-OM complexes and reoxidation of Fe(II) by O2, or microbially by a combination of Fe(III)-reducing and Fe(II)-oxidizing bacteria. Our study demonstrates a new type of light-driven cryptic Fe cycle that is relevant for the photic zone of aquatic habitats involving abiotic photochemical reduction of Fe(III)-OM complexes and microbial phototrophic Fe(II) oxidation. This new type of cryptic Fe cycle has important implications for biogeochemical cycling of iron, carbon, nutrients, and heavy metals and can also influence the composition and activity of microbial communities.
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Affiliation(s)
- Chao Peng
- Geomicrobiology Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Casey Bryce
- Geomicrobiology Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Anneli Sundman
- Geomicrobiology Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Andreas Kappler
- Geomicrobiology Center for Applied Geoscience, University of Tübingen, Tübingen, Germany
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McAllister SM, Moore RM, Gartman A, Luther GW, Emerson D, Chan CS. The Fe(II)-oxidizing Zetaproteobacteria: historical, ecological and genomic perspectives. FEMS Microbiol Ecol 2019; 95:fiz015. [PMID: 30715272 PMCID: PMC6443915 DOI: 10.1093/femsec/fiz015] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 01/29/2019] [Indexed: 01/22/2023] Open
Abstract
The Zetaproteobacteria are a class of bacteria typically associated with marine Fe(II)-oxidizing environments. First discovered in the hydrothermal vents at Loihi Seamount, Hawaii, they have become model organisms for marine microbial Fe(II) oxidation. In addition to deep sea and shallow hydrothermal vents, Zetaproteobacteria are found in coastal sediments, other marine subsurface environments, steel corrosion biofilms and saline terrestrial springs. Isolates from a range of environments all grow by autotrophic Fe(II) oxidation. Their success lies partly in their microaerophily, which enables them to compete with abiotic Fe(II) oxidation at Fe(II)-rich oxic/anoxic transition zones. To determine the known diversity of the Zetaproteobacteria, we have used 16S rRNA gene sequences to define 59 operational taxonomic units (OTUs), at 97% similarity. While some Zetaproteobacteria taxa appear to be cosmopolitan, others are enriched by specific habitats. OTU networks show that certain Zetaproteobacteria co-exist, sharing compatible niches. These niches may correspond with adaptations to O2, H2 and nitrate availability, based on genomic analyses of metabolic potential. Also, a putative Fe(II) oxidation gene has been found in diverse Zetaproteobacteria taxa, suggesting that the Zetaproteobacteria evolved as Fe(II) oxidation specialists. In all, studies suggest that Zetaproteobacteria are widespread, and therefore may have a broad influence on marine and saline terrestrial Fe cycling.
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Affiliation(s)
- Sean M McAllister
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Road, 204 Cannon Lab, Lewes, Delaware, USA 19958
| | - Ryan M Moore
- Center for Bioinformatics and Computational Biology, University of Delaware, 15 Innovation Way, 205 Delaware Biotechnology Institute, Newark, Delaware, USA 19711
| | - Amy Gartman
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Road, 204 Cannon Lab, Lewes, Delaware, USA 19958
| | - George W Luther
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Road, 204 Cannon Lab, Lewes, Delaware, USA 19958
| | - David Emerson
- Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, East Boothbay, Maine, USA 04544
| | - Clara S Chan
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Road, 204 Cannon Lab, Lewes, Delaware, USA 19958
- Department of Geological Sciences, University of Delaware, 101 Penny Hall, Newark, Delaware, USA 19716
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Molecular underpinnings for microbial extracellular electron transfer during biogeochemical cycling of earth elements. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1275-1286. [DOI: 10.1007/s11427-018-9464-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/09/2018] [Indexed: 02/07/2023]
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44
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Bryce C, Blackwell N, Schmidt C, Otte J, Huang YM, Kleindienst S, Tomaszewski E, Schad M, Warter V, Peng C, Byrne JM, Kappler A. Microbial anaerobic Fe(II) oxidation - Ecology, mechanisms and environmental implications. Environ Microbiol 2018; 20:3462-3483. [DOI: 10.1111/1462-2920.14328] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 06/15/2018] [Accepted: 06/16/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Casey Bryce
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Nia Blackwell
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | | | - Julia Otte
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Yu-Ming Huang
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | | | | | - Manuel Schad
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Viola Warter
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Chao Peng
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - James M. Byrne
- Geomicrobiology; University of Tübingen; Tübingen Germany
| | - Andreas Kappler
- Geomicrobiology; University of Tübingen; Tübingen Germany
- Center for Geomicrobiology, Department of Bioscience; Aarhus University; Aarhus Denmark
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45
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Otte JM, Blackwell N, Soos V, Rughöft S, Maisch M, Kappler A, Kleindienst S, Schmidt C. Sterilization impacts on marine sediment---Are we able to inactivate microorganisms in environmental samples? FEMS Microbiol Ecol 2018; 94:5104375. [DOI: 10.1093/femsec/fiy189] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 09/18/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Julia M Otte
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Nia Blackwell
- Microbial Ecology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Viktoria Soos
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Saskia Rughöft
- Microbial Ecology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Markus Maisch
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
- Geomicrobiology, Center for Geomicrobiology, Aarhus University, Ny Munkegade 116, 8000 Aarhus, Denmark
| | - Sara Kleindienst
- Microbial Ecology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
| | - Caroline Schmidt
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
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