1
|
Wu B, Liu F, Liang Z, Wang C, Wang S. Spatial distribution of cable bacteria in nationwide organic-matter-polluted urban rivers in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174118. [PMID: 38925373 DOI: 10.1016/j.scitotenv.2024.174118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/04/2024] [Accepted: 06/16/2024] [Indexed: 06/28/2024]
Abstract
An overload of labile organic matter triggers the water blackening and odorization in urban rivers, leading to a unique microbiome driving biogeochemical cycles in these anoxic habitats. Among the key players in these environments, cable bacteria interfere directly with C/N/S/O cycling, and are closely associated with phylogenetically diverse microorganisms in anoxic sediment as an electron conduit to mediate long-distance electron transport from deep-anoxic-layer sulfide to oxic-layer oxygen. Despite their hypothesized importance in black-odorous urban rivers, the spatial distribution patterns and roles of cable bacteria in large-scale polluted urban rivers remain inadequately understood. This study examined the diversity and spatial distribution pattern of cable bacteria in sediment samples from 186 black-odorous urban rivers across China. Results revealed the co-existence of two well-characterized cable bacteria (i.e., Candidatus Electrothrix and Candidatus Electronema), with Candidatus Electrothrix exhibiting a comparatively wider distribution in the polluted urban rivers. Concentrations of DOC, SS, sulfate, nitrate, and heavy metals (e.g., Ni and Cr) were correlated with the cable bacteria diversity, indicating their essential role in biogeochemical cycles. The activation energy of cable bacteria was 0.624 eV, close to the canonical 0.65 eV. Furthermore, cable bacteria were identified as key connectors and module hubs, closely associated with denitrifiers, sulfate-reducing bacteria, methanogens and alkane degraders, highlighting their role as keystone functional lineages in the contaminated urban rivers. Our study provided the first large-scale and comprehensive insight into the cable bacteria diversity, spatial distribution, and their essential function as keystone species in organic-matter-polluted urban rivers.
Collapse
Affiliation(s)
- Bo Wu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Feifei Liu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; Guangdong Magigene Biotechnology Co. Ltd., 510000 Guangzhou, China
| | - Zhiwei Liang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Chen Wang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China
| | - Shanquan Wang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, China.
| |
Collapse
|
2
|
Dong M, Nielsen LP, Yang S, Klausen LH, Xu M. Cable bacteria: widespread filamentous electroactive microorganisms protecting environments. Trends Microbiol 2024; 32:697-706. [PMID: 38151387 DOI: 10.1016/j.tim.2023.12.001] [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: 08/28/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023]
Abstract
Cable bacteria have been identified and detected worldwide since their discovery in marine sediments in Aarhus Bay, Denmark. Their activity can account for the majority of oxygen consumption and sulfide depletion in sediments, and they induce sulfate accumulation, pH excursions, and the generation of electric fields. In addition, they can affect the fluxes of other elements such as calcium, iron, manganese, nitrogen, and phosphorous. Recent developments in our understanding of the impact of cable bacteria on element cycling have revealed their positive contributions to mitigating environmental problems, such as recovering self-purification capacity, enhancing petroleum hydrocarbon degradation, alleviating phosphorus eutrophication, delaying euxinia, and reducing methane emission. We highlight recent research outcomes on their distribution, state-of-the-art findings on their physiological characteristics, and ecological contributions.
Collapse
Affiliation(s)
- Meijun Dong
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou 510070, Guangdong, China
| | - Lars Peter Nielsen
- Center for Electromicrobiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark
| | - Shan Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou 510070, Guangdong, China
| | - Lasse Hyldgaard Klausen
- Center for Electromicrobiology, Department of Biology, Aarhus University, 8000 Aarhus C, Denmark; Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C, Denmark
| | - Meiying Xu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; Guangdong Provincial Key Laboratory of Environmental Protection Microbiology and Regional Ecological Security, Guangzhou 510070, Guangdong, China.
| |
Collapse
|
3
|
Stiefelmaier J, Keller J, Neupert W, Ulber R. Towards bioprocess engineering of cable bacteria: Establishment of a synthetic sediment. Microbiologyopen 2024; 13:e1412. [PMID: 38711353 DOI: 10.1002/mbo3.1412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 04/12/2024] [Accepted: 04/20/2024] [Indexed: 05/08/2024] Open
Abstract
Cable bacteria, characterized by their multicellular filamentous growth, are prevalent in both freshwater and marine sediments. They possess the unique ability to transport electrons over distances of centimeters. Coupled with their capacity to fix CO2 and their record-breaking conductivity for biological materials, these bacteria present promising prospects for bioprocess engineering, including potential electrochemical applications. However, the cultivation of cable bacteria has been limited to their natural sediment, constraining their utility in production processes. To address this, our study designs synthetic sediment, drawing on ion exchange chromatography data from natural sediments and existing literature on the requirements of cable bacteria. We examined the effects of varying bentonite concentrations on water retention and the impacts of different sands. For the first time, we cultivated cable bacteria on synthetic sediment, specifically the freshwater strain Electronema aureum GS. This cultivation was conducted over 10 weeks in a specially developed sediment bioreactor, resulting in an increased density of cable bacteria in the sediment and growth up to a depth of 5 cm. The creation of this synthetic sediment paves the way for the reproducible cultivation of cable bacteria. It also opens up possibilities for future process scale-up using readily available components. This advancement holds significant implications for the broader field of bioprocess engineering.
Collapse
Affiliation(s)
- Judith Stiefelmaier
- Chair of Bioprocess Engineering, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Joshua Keller
- Chair of Bioprocess Engineering, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Wiebke Neupert
- Chair of Bioprocess Engineering, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Roland Ulber
- Chair of Bioprocess Engineering, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Plum-Jensen LE, Schramm A, Marshall IPG. First single-strain enrichments of Electrothrix cable bacteria, description of E. aestuarii sp. nov. and E. rattekaaiensis sp. nov., and proposal of a cable bacteria taxonomy following the rules of the SeqCode. Syst Appl Microbiol 2024; 47:126487. [PMID: 38295603 DOI: 10.1016/j.syapm.2024.126487] [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: 07/30/2023] [Revised: 12/23/2023] [Accepted: 01/15/2024] [Indexed: 02/02/2024]
Abstract
Cable bacteria are electrically conductive, filamentous Desulfobulbaceae, which are morphologically, functionally, and phylogenetically distinct from the other members of this family. Cable bacteria have not been obtained in pure culture and were therefore previously described as candidate genera, Candidatus Electrothrix and Ca. Electronema; a representative of the latter is available as single-strain sediment enrichment. Here we present an improved workflow to obtain the first single-strain enrichments of Ca. Electrothrix and report their metagenome-assembled genomes (MAGs) and morphology. Based on these results and on previously published high-quality MAGs and morphological data of cable bacteria from both candidate genera, we propose to adopt the genus names Electrothrix and Electronema following the rules of the Code of Nomenclature of Prokaryotes Described from Sequence Data (SeqCode), with Electrothrix communis RBTS and Electronema aureum GSTS, respectively, as the nomenclatural types of the genera. Furthermore, based on average nucleotide identity (ANI) values < 95 % with any described species, we propose two of our three single-strain enrichment cultures as novel species of the genus Electrothrix, with the names E. aestuarii sp. nov. and E. rattekaaiensis sp. nov., according to the SeqCode.
Collapse
Affiliation(s)
- Lea E Plum-Jensen
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| | - Andreas Schramm
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| | - Ian P G Marshall
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| |
Collapse
|
6
|
Geelhoed JS, Thorup CA, Bjerg JJ, Schreiber L, Nielsen LP, Schramm A, Meysman FJR, Marshall IPG. Indications for a genetic basis for big bacteria and description of the giant cable bacterium Candidatus Electrothrix gigas sp. nov. Microbiol Spectr 2023; 11:e0053823. [PMID: 37732806 PMCID: PMC10580974 DOI: 10.1128/spectrum.00538-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/21/2023] [Indexed: 09/22/2023] Open
Abstract
Bacterial cells can vary greatly in size, from a few hundred nanometers to hundreds of micrometers in diameter. Filamentous cable bacteria also display substantial size differences, with filament diameters ranging from 0.4 to 8 µm. We analyzed the genomes of cable bacterium filaments from 11 coastal environments of which the resulting 23 new genomes represent 10 novel species-level clades of Candidatus Electrothrix and two clades that putatively represent novel genus-level diversity. Fluorescence in situ hybridization with a species-level probe showed that large-sized cable bacteria belong to a novel species with the proposed name Ca. Electrothrix gigas. Comparative genome analysis suggests genes that play a role in the construction or functioning of large cable bacteria cells: the genomes of Ca. Electrothrix gigas encode a novel actin-like protein as well as a species-specific gene cluster encoding four putative pilin proteins and a putative type II secretion platform protein, which are not present in other cable bacteria. The novel actin-like protein was also found in a number of other giant bacteria, suggesting there could be a genetic basis for large cell size. This actin-like protein (denoted big bacteria protein, Bbp) may have a function analogous to other actin proteins in cell structure or intracellular transport. We contend that Bbp may help overcome the challenges of diffusion limitation and/or morphological complexity presented by the large cells of Ca. Electrothrix gigas and other giant bacteria. IMPORTANCE In this study, we substantially expand the known diversity of marine cable bacteria and describe cable bacteria with a large diameter as a novel species with the proposed name Candidatus Electrothrix gigas. In the genomes of this species, we identified a gene that encodes a novel actin-like protein [denoted big bacteria protein (Bbp)]. The bbp gene was also found in a number of other giant bacteria, predominantly affiliated to Desulfobacterota and Gammaproteobacteria, indicating that there may be a genetic basis for large cell size. Thus far, mostly structural adaptations of giant bacteria, vacuoles, and other inclusions or organelles have been observed, which are employed to overcome nutrient diffusion limitation in their environment. In analogy to other actin proteins, Bbp could fulfill a structural role in the cell or potentially facilitate intracellular transport.
Collapse
Affiliation(s)
- Jeanine S. Geelhoed
- Department of Biology, Research Group Geobiology, University of Antwerp, Wilrijk, Belgium
| | - Casper A. Thorup
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Jesper J. Bjerg
- Department of Biology, Research Group Geobiology, University of Antwerp, Wilrijk, Belgium
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Lars Schreiber
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Lars Peter Nielsen
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Filip J. R. Meysman
- Department of Biology, Research Group Geobiology, University of Antwerp, Wilrijk, Belgium
- Department of Biotechnology, Delft University of Technology, Delft, the Netherlands
| | - Ian P. G. Marshall
- Department of Biology, Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| |
Collapse
|
7
|
Xu X, Weng N, Zhang H, van de Velde SJ, Hermans M, Wu F, Huo S. Cable bacteria regulate sedimentary phosphorus release in freshwater sediments. WATER RESEARCH 2023; 242:120218. [PMID: 37390661 DOI: 10.1016/j.watres.2023.120218] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/14/2023] [Accepted: 06/11/2023] [Indexed: 07/02/2023]
Abstract
Previous studies have demonstrated that e-SOx can regulate the sedimentary release of phosphorus (P) in brackish and marine sediments. When e-SOx is active, an iron (Fe) and manganese (Mn) oxide rich layer is formed near the sediment surface, which prevents P release. When e-SOx becomes inactive, the metal oxide layer is reduced via sulfide-mediated dissolution, and P is subsequently released to the water column. Cable bacteria have been shown to also occur in freshwater sediments. In these sediments, sulfide production is limited, and the metal oxide layer would thus dissolve less efficiently, leaving the P trapped at the sediment surface. This lack of an efficient dissolution mechanism implies that e-SOx could play an important role in the regulation of P availability in eutrophied freshwater streams. To test this hypothesis, we incubated sediments from a eutrophic freshwater river to investigate the impact of cable bacteria on sedimentary cycling of Fe, Mn and P. High-resolution depth profiling of pH, O2 and ΣH2S complemented with FISH analysis and high-throughput gene sequencing showed that the development of e-SOx activity was closely linked to the enrichment of cable bacteria in incubated sediments. Cable bacteria activity caused a strong acidification in the suboxic zone, leading to the dissolution of Fe and Mn minerals and consequently a strong release of dissolved Fe2+ and Mn2+ to the porewater. Oxidation of these mobilized ions at the sediment surface led to the formation of a metal oxide layer that trapped dissolved P, as shown by the enrichment of P-bearing metal oxides in the top layer of the sediment and low phosphate in the pore and overlying water. After e-SOx activity declined, the metal oxide layer did not dissolve and P remained trapped at the surface. Overall, our results suggested cable bacteria can play an important role to counteract eutrophication in freshwater systems.
Collapse
Affiliation(s)
- Xiaoling Xu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Nanyan Weng
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
| | - Hanxiao Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Sebastiaan J van de Velde
- Department of Biology, University of Antwerp, Wilrijk, Belgium; Operationale Directorate Natural Environment, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Martijn Hermans
- Baltic Sea Centre, Stockholm University, Stockholm 106 91, Sweden; Environmental Geochemistry Group, Faculty of Science, University of Helsinki, Helsinki 00560, Finland
| | - Fengchang Wu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Shouliang Huo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
| |
Collapse
|
8
|
Sereika M, Petriglieri F, Jensen TBN, Sannikov A, Hoppe M, Nielsen PH, Marshall IPG, Schramm A, Albertsen M. Closed genomes uncover a saltwater species of Candidatus Electronema and shed new light on the boundary between marine and freshwater cable bacteria. THE ISME JOURNAL 2023; 17:561-569. [PMID: 36697964 PMCID: PMC10030654 DOI: 10.1038/s41396-023-01372-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/26/2023]
Abstract
Cable bacteria of the Desulfobulbaceae family are centimeter-long filamentous bacteria, which are capable of conducting long-distance electron transfer. Currently, all cable bacteria are classified into two candidate genera: Candidatus Electronema, typically found in freshwater environments, and Candidatus Electrothrix, typically found in saltwater environments. This taxonomic framework is based on both 16S rRNA gene sequences and metagenome-assembled genome (MAG) phylogenies. However, most of the currently available MAGs are highly fragmented, incomplete, and thus likely miss key genes essential for deciphering the physiology of cable bacteria. Also, a closed, circular genome of cable bacteria has not been published yet. To address this, we performed Nanopore long-read and Illumina short-read shotgun sequencing of selected environmental samples and a single-strain enrichment of Ca. Electronema aureum. We recovered multiple cable bacteria MAGs, including two circular and one single-contig. Phylogenomic analysis, also confirmed by 16S rRNA gene-based phylogeny, classified one circular MAG and the single-contig MAG as novel species of cable bacteria, which we propose to name Ca. Electronema halotolerans and Ca. Electrothrix laxa, respectively. The Ca. Electronema halotolerans, despite belonging to the previously recognized freshwater genus of cable bacteria, was retrieved from brackish-water sediment. Metabolic predictions showed several adaptations to a high salinity environment, similar to the "saltwater" Ca. Electrothrix species, indicating how Ca. Electronema halotolerans may be the evolutionary link between marine and freshwater cable bacteria lineages.
Collapse
Affiliation(s)
- Mantas Sereika
- Center for Microbial Communities, Aalborg University, Aalborg, Denmark
| | | | | | - Artur Sannikov
- Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Morten Hoppe
- Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | | | - Ian P G Marshall
- Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Center for Electromicrobiology, Aarhus University, Aarhus, Denmark
| | - Mads Albertsen
- Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
| |
Collapse
|
9
|
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: 1] [Impact Index Per Article: 0.5] [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.
Collapse
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
| |
Collapse
|
10
|
Dong M, Yang S, Yang X, Xu M, Hu W, Wang B, Huang Y, Xu J, Lu H, Yang Y, Chen X, Huang H, Sun G. Water quality drives the distribution of freshwater cable bacteria. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 841:156468. [PMID: 35660596 DOI: 10.1016/j.scitotenv.2022.156468] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Cable bacteria are a group of recently found filamentous sulfide-oxidizing Desulfobulbaceae that significantly impact biogeochemical cycling. However, the limited understanding of cable bacteria distribution patterns and the driving force hindered our abilities to evaluate and maximize their contribution to environmental health. We evaluated cable bacteria assemblages from ten river sediments in the Pearl River Delta, China. The results revealed a clear biogeographic distribution pattern of cable bacteria, and their communities were deterministically assembled through water quality-driven selection. Cable bacteria are diverse in the river sediments with a few generalists and many specialists, and the water quality IV and V environments are the "hot spot." We then provided evidence on their morphology, function, and genome to demonstrate how water quality might shape the cable bacteria assemblages. Reduced cell width, inhibited function, and water quality-related adaptive genomic traits were detected in sulfide-limited water quality III and contaminant-stressed water quality VI environments. Specifically, those genomic traits were contributed to carbon and sulfur metabolism in the water quality III environment and stress resistance in the water quality VI environment. Overall, these findings provided a helpful baseline in evaluating the contribution of cable bacteria in the freshwater ecosystem and suggested that their high diversity and flexibility in phylogeny, morphology, and genome allowed them to adapt and contribute to various environmental conditions.
Collapse
Affiliation(s)
- Meijun Dong
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Shan Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Xunan Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Meiying Xu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Wenzhe Hu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Bin Wang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Youda Huang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Jiarou Xu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Huibin Lu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Yonggang Yang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Xingjuan Chen
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Haobin Huang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| | - Guoping Sun
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
| |
Collapse
|
11
|
Fonseca A, Espinoza C, Nielsen LP, Marshall IPG, Gallardo VA. Bacterial community of sediments under the Eastern Boundary Current System shows high microdiversity and a latitudinal spatial pattern. Front Microbiol 2022; 13:1016418. [PMID: 36246233 PMCID: PMC9561620 DOI: 10.3389/fmicb.2022.1016418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/16/2022] [Indexed: 11/13/2022] Open
Abstract
The sediments under the Oxygen Minimum Zone of the Eastern Boundary Current System (EBCS) along Central-South Peru and North-Central Chile, known as Humboldt Sulfuretum (HS), is an organic-matter-rich benthic habitat, where bacteria process a variety of sulfur compounds under low dissolved-oxygen concentrations, and high sulfide and nitrate levels. This study addressed the structure, diversity and spatial distribution patterns of the HS bacterial community along Northern and South-Central Chile using 16S rRNA gene amplicon sequencing. The results show that during the field study period, the community was dominated by sulfur-associated bacteria. Indeed, the most abundant phylum was Desulfobacterota, while Sva0081 sedimentary group, of the family Desulfosarcinaceae (the most abundant family), which includes sulfate-reducer and H2 scavenger bacteria, was the most abundant genus. Furthermore, a spatial pattern was unveiled along the study area to which the family Desulfobulbaceae contributed the most to the spatial variance, which encompasses 42 uncharacterized amplicon sequence variants (ASVs), three assigned to Ca. Electrothrix and two to Desulfobulbus. Moreover, a very high microdiversity was found, since only 3.7% of the ASVs were shared among localities, reflecting a highly diverse and mature community.
Collapse
Affiliation(s)
- Alexis Fonseca
- Center for Electromicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
- *Correspondence: Alexis Fonseca,
| | - Carola Espinoza
- Department of Oceanography, University of Concepción, Concepción, Chile
| | - Lars Peter Nielsen
- Center for Electromicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Ian P. G. Marshall
- Center for Electromicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Victor A. Gallardo
- Department of Oceanography, University of Concepción, Concepción, Chile
- Victor A. Gallardo,
| |
Collapse
|
12
|
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: 0] [Impact Index Per Article: 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.
Collapse
|
13
|
Sachs C, Kanaparthi D, Kublik S, Szalay AR, Schloter M, Damgaard LR, Schramm A, Lueders T. Tracing long-distance electron transfer and cable bacteria in freshwater sediments by agar pillar gradient columns. FEMS Microbiol Ecol 2022; 98:6567839. [PMID: 35416241 DOI: 10.1093/femsec/fiac042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/20/2022] [Accepted: 04/11/2022] [Indexed: 11/14/2022] Open
Abstract
Cable bacteria (CB) perform electrogenic sulphur oxidation (e-SOX) by spatially separating redox-half-reactions over cm-distances. For freshwater systems, the ecology of CB is not yet well understood, partly because they proved difficult to cultivate. This study introduces a new "agar pillar" approach to selectively enrich and investigate CB-populations. Within sediment columns, a central agar pillar is embedded, providing a sediment-free gradient-system in equilibrium with the surrounding sediment. We incubated freshwater sediments from a streambed, a sulfidic lake, and a hydrocarbon polluted aquifer in such agar pillar columns. Microprofiling revealed typical patterns of e-SOx, such as the development of a suboxic zone and the establishment of electric potentials. The bacterial communities in the sediments and agar pillars were analysed over depth by PacBio near-full-length 16S rRNA gene amplicon sequencing, allowing for a precise phylogenetic placement of taxa detected. The selective niche of the agar pillar was preferentially colonized by CB related to Candidatus Electronema for surface-water sediments, including several potentially novel species, but not for putative groundwater CB affiliated with Desulfurivibrio spp. The presence of CB was seemingly linked to co-enriched fermenters, hinting at a possible role of e-SOx-populations as an electron sink for heterotrophic microbes. These findings add to our current understanding of the diversity and ecology of CB in freshwater systems, and to a discrimination of CB from surface and groundwater sediments. The agar pillar approach provides a new strategy that may facilitate the cultivation of redox gradient-dependent microorganisms, including previously unrecognized CB populations.
Collapse
Affiliation(s)
- Corinna Sachs
- Chair of Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Germany.,Institute of Groundwater Ecology, Helmholtz Zentrum München - German Research Center for Environmental Health, Germany
| | - Dheeraj Kanaparthi
- Chair of Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Germany.,Institute of Groundwater Ecology, Helmholtz Zentrum München - German Research Center for Environmental Health, Germany
| | - Susanne Kublik
- Research Unit Comparative Microbiome Analysis, Helmholtz Zentrum München - German Research Center for Environmental Health, Germany
| | - Anna Roza Szalay
- Institute of Groundwater Ecology, Helmholtz Zentrum München - German Research Center for Environmental Health, Germany
| | - Michael Schloter
- Research Unit Comparative Microbiome Analysis, Helmholtz Zentrum München - German Research Center for Environmental Health, Germany
| | - Lars Riis Damgaard
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Denmark
| | - Andreas Schramm
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Denmark
| | - Tillmann Lueders
- Chair of Ecological Microbiology, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Germany
| |
Collapse
|
14
|
Xu X, Huo S, Weng N, Zhang H, Ma C, Zhang J, Wu F. Effects of sulfide availability on the metabolic activity and population dynamics of cable bacteria in freshwater sediment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:151817. [PMID: 34848270 DOI: 10.1016/j.scitotenv.2021.151817] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/10/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Cable bacteria occur in many natural environments, and their electrogenic sulfide oxidation (e-SOx) may influence sediment biogeochemistry. The environmental factors determining the growth and diversity of cable bacteria are poorly known, especially in freshwater sediments. We conducted a laboratory incubation experiment, using freshwater sediments with different sulfide supply levels, to study how sulfide availability in sediment affects the metabolic activity and population dynamics of cable bacteria. A moderate increase in the sulfide availability in sediment significantly promoted metabolic activity and the proliferation of the cable bacteria population, as revealed by enhanced e-SOx intensity and increased bacteria abundance. In high-sulfide treatments there was a more significant increase in the population of cable bacteria in the deeper sediment layers, indicating that increased sulfide availability may expand the vertical scale impact of cable bacteria activities on sediment biogeochemistry. The relative proportions of co-existing species in the cable bacteria population also changed with sulfide supply levels, indicating that sulfide availability can be involved in determining the interspecies relationships of cable bacteria. Our findings provide new insight into the relationship between sediment sulfide availability and the growth, depth distribution, and species composition of cable bacteria, implying the consideration of regulating environmental sulfide availability as a potential management practice for the development of cable bacteria-based environmental biotechnologies.
Collapse
Affiliation(s)
- Xiaoling Xu
- College of Water Sciences, Beijing Normal University, Beijing 100012, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Shouliang Huo
- College of Water Sciences, Beijing Normal University, Beijing 100012, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
| | - Nanyan Weng
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Hanxiao Zhang
- College of Water Sciences, Beijing Normal University, Beijing 100012, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Chunzi Ma
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Jingtian Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Fengchang Wu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| |
Collapse
|
15
|
Marzocchi U, Thorup C, Dam AS, Schramm A, Risgaard-Petersen N. Dissimilatory nitrate reduction by a freshwater cable bacterium. THE ISME JOURNAL 2022; 16:50-57. [PMID: 34215856 PMCID: PMC8692496 DOI: 10.1038/s41396-021-01048-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023]
Abstract
Cable bacteria (CB) are filamentous Desulfobulbaceae that split the energy-conserving reaction of sulfide oxidation into two half reactions occurring in distinct cells. CB can use nitrate, but the reduction pathway is unknown, making it difficult to assess their direct impact on the N-cycle. Here we show that the freshwater cable bacterium Ca. Electronema sp. GS performs dissimilatory nitrate reduction to ammonium (DNRA). 15NO3--amended sediment with Ca. Electronema sp. GS showed higher rates of DNRA and nitrite production than sediment without Ca. Electronema sp. GS. Electron flux from sulfide oxidation, inferred from electric potential (EP) measurements, matched the electron flux needed to drive CB-mediated nitrate reduction to nitrite and ammonium. Ca. Electronema sp. GS expressed a complete nap operon for periplasmic nitrate reduction to nitrite, and a putative octaheme cytochrome c (pOCC), whose involvement in nitrite reduction to ammonium remains to be verified. Phylogenetic analysis suggests that the capacity for DNRA was acquired in multiple events through horizontal gene transfer from different organisms, before CB split into different salinity niches. The architecture of the nitrate reduction system suggests absence of energy conservation through oxidative phosphorylation, indicating that CB primarily conserve energy through the half reaction of sulfide oxidation.
Collapse
Affiliation(s)
- Ugo Marzocchi
- grid.8767.e0000 0001 2290 8069Department of Chemistry, Vrije Universiteit Brussel, Brussel, Belgium ,grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.7048.b0000 0001 1956 2722Center for Water Technology (WATEC), Department of Biology, Aarhus University, Aarhus, Denmark
| | - Casper Thorup
- grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Ann-Sofie Dam
- grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Nils Risgaard-Petersen
- grid.7048.b0000 0001 1956 2722Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.7048.b0000 0001 1956 2722Section of Aquatic Biology, Department of Biology, Aarhus University, Aarhus, Denmark
| |
Collapse
|
16
|
Scholz VV, Martin BC, Meyer R, Schramm A, Fraser MW, Nielsen LP, Kendrick GA, Risgaard‐Petersen N, Burdorf LDW, Marshall IPG. Cable bacteria at oxygen-releasing roots of aquatic plants: a widespread and diverse plant-microbe association. THE NEW PHYTOLOGIST 2021; 232:2138-2151. [PMID: 33891715 PMCID: PMC8596878 DOI: 10.1111/nph.17415] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 05/09/2023]
Abstract
Cable bacteria are sulfide-oxidising, filamentous bacteria that reduce toxic sulfide levels, suppress methane emissions and drive nutrient and carbon cycling in sediments. Recently, cable bacteria have been found associated with roots of aquatic plants and rice (Oryza sativa). However, the extent to which cable bacteria are associated with aquatic plants in nature remains unexplored. Using newly generated and public 16S rRNA gene sequence datasets combined with fluorescence in situ hybridisation, we investigated the distribution of cable bacteria around the roots of aquatic plants, encompassing seagrass (including seagrass seedlings), rice, freshwater and saltmarsh plants. Diverse cable bacteria were found associated with roots of 16 out of 28 plant species and at 36 out of 55 investigated sites, across four continents. Plant-associated cable bacteria were confirmed across a variety of ecosystems, including marine coastal environments, estuaries, freshwater streams, isolated pristine lakes and intensive agricultural systems. This pattern indicates that this plant-microbe relationship is globally widespread and neither obligate nor species specific. The occurrence of cable bacteria in plant rhizospheres may be of general importance to vegetation vitality, primary productivity, coastal restoration practices and greenhouse gas balance of rice fields and wetlands.
Collapse
Affiliation(s)
- Vincent V. Scholz
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
| | - Belinda C. Martin
- School of Biological SciencesThe University of Western Australia35 Stirling HighwayCrawleyWA6009Australia
- The UWA Oceans InstituteThe University of Western Australia35 Stirling HighwayCrawleyWA6009Australia
- Ooid ScientificWhite Gum ValleyWA6162Australia
| | - Raïssa Meyer
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
- Max Planck Institute for Marine MicrobiologyCelsiusstraße 1BremenD‐28359Germany
| | - Andreas Schramm
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
| | - Matthew W. Fraser
- School of Biological SciencesThe University of Western Australia35 Stirling HighwayCrawleyWA6009Australia
- The UWA Oceans InstituteThe University of Western Australia35 Stirling HighwayCrawleyWA6009Australia
| | - Lars Peter Nielsen
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
| | - Gary A. Kendrick
- School of Biological SciencesThe University of Western Australia35 Stirling HighwayCrawleyWA6009Australia
- The UWA Oceans InstituteThe University of Western Australia35 Stirling HighwayCrawleyWA6009Australia
| | - Nils Risgaard‐Petersen
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
| | - Laurine D. W. Burdorf
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
| | - Ian P. G. Marshall
- Section for MicrobiologyDepartment of BiologyCenter for ElectromicrobiologyAarhus UniversityNy Munkegade 116Aarhus CDK‐8000Denmark
| |
Collapse
|
17
|
Using Oxidative Electrodes to Enrich Novel Members in the Desulfobulbaceae Family from Intertidal Sediments. Microorganisms 2021; 9:microorganisms9112329. [PMID: 34835454 PMCID: PMC8618199 DOI: 10.3390/microorganisms9112329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 10/21/2021] [Accepted: 11/08/2021] [Indexed: 01/04/2023] Open
Abstract
Members in the family of Desulfobulbaceae may be influential in various anaerobic microbial communities, including those in anoxic aquatic sediments and water columns, and within wastewater treatment facilities and bioelectrochemical systems (BESs) such as microbial fuel cells (MFCs). However, the diversity and roles of the Desulfobulbaceae in these communities have received little attention, and large portions of this family remain uncultured. Here we expand on findings from an earlier study (Li, Reimers, and Alleau, 2020) to more fully characterize Desulfobulbaceae that became prevalent in biofilms on oxidative electrodes of bioelectrochemical reactors. After incubations, DNA extraction, microbial community analyses, and microscopic examination, we found that a group of uncultured Desulfobulbaceae were greatly enriched on electrode surfaces. These Desulfobulbaceae appeared to form filaments with morphological features ascribed to cable bacteria, but the majority were taxonomically distinct from recognized cable bacteria genera. Thus, the present study provides new information about a group of Desulfobulbaceae that can exhibit filamentous morphologies and respire on the oxidative electrodes. While the phylogeny of cable bacteria is still being defined and updated, further enriching these members can contribute to the overall understanding of cable bacteria and may also lead to identification of successful isolation strategies.
Collapse
|
18
|
Thorup C, Petro C, Bøggild A, Ebsen TS, Brokjær S, Nielsen LP, Schramm A, Bjerg JJ. How to grow your cable bacteria: Establishment of a stable single-strain culture in sediment and proposal of Candidatus Electronema aureum GS. Syst Appl Microbiol 2021; 44:126236. [PMID: 34332367 DOI: 10.1016/j.syapm.2021.126236] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/08/2021] [Accepted: 07/12/2021] [Indexed: 01/04/2023]
Abstract
Cable bacteria are multicellular filamentous bacteria within the Desulfobulbaceae that couple the oxidation of sulfide to the reduction of oxygen over centimeter distances via long distance electron transport (LDET). So far, none of the freshwater or marine cable bacteria species have been isolated into pure culture. Here we describe a method for establishing a stable single-strain cable bacterium culture in partially sterilized sediment. By repeated transfers of a single cable bacterium filament from freshwater pond sediment into autoclaved sediment, we obtained strain GS, identified by its 16S rRNA gene as a member of Ca. Electronema. This strain was further propagated by transferring sediment clumps, and has now been stable within its semi-natural microbial community for several years. Its metagenome-assembled genome was 93% complete, had a size of 2.76 Mbp, and a DNA G + C content of 52%. Average Nucleotide Identity (ANI) and Average Amino Acid Identity (AAI) suggest the affiliation of strain GS to Ca. Electronema as a novel species. Cell size, number of outer ridges, and detection of LDET in the GS culture are likewise consistent with Ca. Electronema. Based on these combined features, we therefore describe strain GS as a new cable bacterium species of the candidate genus Electronema, for which we propose the name Candidatus Electronema aureum sp.nov. Although not a pure culture, this stable single-strain culture will be useful for physiological and omics-based studies; similar approaches with single-cell or single-filament transfers into natural medium may also aid the characterization of other difficult-to-culture microbes.
Collapse
Affiliation(s)
- Casper Thorup
- Section for Microbiology, Department of Biology, Aarhus University, Denmark; Center for Electromicrobiology, Aarhus University, Denmark; Center for Geomicrobiology, Aarhus University, Denmark
| | - Caitlin Petro
- Section for Microbiology, Department of Biology, Aarhus University, Denmark; Center for Electromicrobiology, Aarhus University, Denmark; Center for Geomicrobiology, Aarhus University, Denmark
| | - Andreas Bøggild
- Department for Molecular Biology and Genetics, Aarhus University, Denmark
| | | | - Signe Brokjær
- Section for Microbiology, Department of Biology, Aarhus University, Denmark
| | - Lars Peter Nielsen
- Section for Microbiology, Department of Biology, Aarhus University, Denmark; Center for Electromicrobiology, Aarhus University, Denmark; Center for Geomicrobiology, Aarhus University, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Denmark; Center for Electromicrobiology, Aarhus University, Denmark; Center for Geomicrobiology, Aarhus University, Denmark.
| | - Jesper Jensen Bjerg
- Section for Microbiology, Department of Biology, Aarhus University, Denmark; Center for Electromicrobiology, Aarhus University, Denmark; Center for Geomicrobiology, Aarhus University, Denmark; ECOBE, Department of Biology, University of Antwerp, Belgium
| |
Collapse
|