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Liu GH, Yang S, Han S, Xie CJ, Liu X, Rensing C, Zhou SG. Nitrogen fixation and transcriptome of a new diazotrophic Geomonas from paddy soils. mBio 2023; 14:e0215023. [PMID: 37855611 PMCID: PMC10746287 DOI: 10.1128/mbio.02150-23] [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: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 10/20/2023] Open
Abstract
IMPORTANCE The ability of Geomonas species to fix nitrogen gas (N2) is an important metabolic feature for its application as a plant growth-promoting rhizobacterium. This research is of great importance as it provides the first comprehensive direct experimental evidence of nitrogen fixation by the genus Geomonas in pure culture. We isolated a number of Geomonas strains from paddy soils and determined that nifH was present in these strains. This study demonstrated that these Geomonas species harbored genes encoding nitrogenase, as do Geobacter and Anaeromyxobacter in the same class of Deltaproteobacteria. We demonstrated N2-dependent growth of Geomonas and determined regulation of gene expression associated with nitrogen fixation. The research establishes and advances our understanding of nitrogen fixation in Geomonas.
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Affiliation(s)
- Guo-Hong Liu
- Institute of Resources, Environment and Soil Fertilizer, Fujian Academy of Agricultural Sciences, Fuzhou City, Fujian Province, China
| | - Shang Yang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shuang Han
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Cheng-Jie Xie
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Xing Liu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Christopher Rensing
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
| | - Shun-Gui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province, China
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2
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Acetylenotrophic and Diazotrophic
Bradyrhizobium
sp. Strain I71 from TCE-Contaminated Soils. Appl Environ Microbiol 2022; 88:e0121922. [PMID: 36286524 PMCID: PMC9680620 DOI: 10.1128/aem.01219-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The isolation of
Bradyrhizobium
strain I71 expands the distribution of acetylene-consuming microbes to include a group of economically important microorganisms. Members of
Bradyrhizobium
are well studied for their abilities to improve plant health and increase crop yields by providing bioavailable nitrogen.
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3
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Wang B, Kuang S, Shao H, Wang L, Wang H. Anaerobic-petroleum degrading bacteria: Diversity and biotechnological applications for improving coastal soil. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 224:112646. [PMID: 34399124 DOI: 10.1016/j.ecoenv.2021.112646] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Due to the industrial emissions and accidental spills, the critical material for modern industrial society petroleum pollution causes severe ecological damage. The prosperous oil exploitation and transportation causes the recalcitrant, hazardous, and carcinogenic sludge widespread in the coastal wetlands. The costly physicochemical-based remediation remains the secondary and inadequate treatment for the derivatives along with the tailings. Anaerobic microbial petroleum degrading biotechnology has received extensive attention for its cost acceptable, eco-friendly, and fewer health hazards. As a result of the advances in biotechnology and microbiology, the anaerobic oil-degrading bacteria have been well developing to achieve the same remediation effects with lower operating costs. This review summarizes the advantages and potential scenarios of the anaerobic degrading bacteria, such as sulfate-reducing bacteria, denitrifying bacteria, and metal-reducing bacteria in the coastal area decomposing the alkanes, alkenes, aromatic hydrocarbons, polycyclic aromatic, and related derivatives. In the future, a complete theoretical basis of microbiological biotechnology, molecular biology, and electrochemistry is necessary to make efficient and environmental-friendly use of anaerobic degradation bacteria to mineralize oil sludge organic wastes.
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Affiliation(s)
- Bingchen Wang
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Shaoping Kuang
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
| | - Hongbo Shao
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China; Institute of Agriculture Resources and Environment, Jiangsu Academy of Agricultural Sciences (JAAS), Nanjing 210014, PR China; Jiangsu Key Laboratory for Bioresources of Saline Soils, Jiangsu Synthetic Innovation Center for Coastal Bio-agriculture, Yancheng Teachers University, Yancheng 224002, China.
| | - Lei Wang
- College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
| | - Huihui Wang
- College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China
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4
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Oremland RS. Got acetylene: a personal research retrospective. FEMS MICROBES 2021; 2:xtab009. [PMID: 37334230 PMCID: PMC10117869 DOI: 10.1093/femsmc/xtab009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/28/2021] [Indexed: 07/20/2023] Open
Abstract
In research, sometimes sheer happenstance and serendipity make for an unexpected discovery. Once revealed and if interesting enough, such a finding and its follow-up investigations can lead to advances by others that leave its originators 'scooped' and mulling about what next to do with their unpublished data, specifically what journals could it still be published in and be perceived as original. This is what occurred with us nearly 40 years ago with regard to our follow-up observations of acetylene fermentation and led us to concoct a 'cock-and-bull' story. We hypothesized about a plausible role for acetylene metabolism in the primordial biogeochemistry of Earth and the possibility of acetylene serving as a key life-sustaining substrate for alien microbes dwelling in the orbs of the outer solar system. With the passage of time, advances were made in whole-genome sequencing coupled with major in silico progress in bioinformatics. In parallel came the results of explorations of the outer solar system (i.e. the Cassini mission to Saturn and its moons). It now appears that these somewhat harebrained ideas of ours, arisen at first out of a sense of desperation, actually ring true in fact, and particularly well in song: 'Tell a tale of cock and bull, Of convincing detail full Tale tremendous, Heav'n defend us! What a tale of cock and bull!' From 'The Yeoman of the Guard' by Gilbert & Sullivan.
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Affiliation(s)
- Ronald S Oremland
- Corresponding author: US Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, USA. E-mail:
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5
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Baesman SM, Sutton JM, Fierst JL, Akob DM, Oremland RS. Syntrophotalea acetylenivorans sp. nov., a diazotrophic, acetylenotrophic anaerobe isolated from intertidal sediments. Int J Syst Evol Microbiol 2021; 71. [PMID: 33570486 DOI: 10.1099/ijsem.0.004698] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A Gram-stain-negative, strictly anaerobic, non-motile, rod-shaped bacterium, designated SFB93T, was isolated from the intertidal sediments of South San Francisco Bay, located near Palo Alto, CA, USA. SFB93T was capable of acetylenotrophic and diazotrophic growth, grew at 22-37 °C, pH 6.3-8.5 and in the presence of 10-45 g l-1 NaCl. Phylogenetic analyses based on 16S rRNA gene sequencing showed that SFB93T represented a member of the genus Syntrophotalea with highest 16S rRNA gene sequence similarities to Syntrophotalea acetylenica DSM 3246T (96.6 %), Syntrophotalea carbinolica DSM 2380T (96.5 %), and Syntrophotalea venetiana DSM 2394T (96.7 %). Genome sequencing revealed a genome size of 3.22 Mbp and a DNA G+C content of 53.4 %. SFB93T had low genome-wide average nucleotide identity (81-87.5 %) and <70 % digital DNA-DNA hybridization value with other members of the genus Syntrophotalea. The phylogenetic position of SFB93T within the family Syntrophotaleaceae and as a novel member of the genus Syntrophotalea was confirmed via phylogenetic reconstruction based on concatenated alignments of 92 bacterial core genes. On the basis of the results of phenotypic, genotypic and phylogenetic analyses, a novel species, Syntrophotalea acetylenivorans sp. nov., is proposed, with SFB93T (=DSM 106009T=JCM 33327T=ATCC TSD-118T) as the type strain.
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Affiliation(s)
- Shaun M Baesman
- U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California, USA
| | - John M Sutton
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, USA
| | - Janna L Fierst
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, USA
| | - Denise M Akob
- U.S. Geological Survey, 12201 Sunrise Valley Dr., MS 954 Reston, Virginia, USA
| | - Ronald S Oremland
- U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California, USA
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6
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Gushgari-Doyle S, Oremland RS, Keren R, Baesman SM, Akob DM, Banfield JF, Alvarez-Cohen L. Acetylene-Fueled Trichloroethene Reductive Dechlorination in a Groundwater Enrichment Culture. mBio 2021; 12:e02724-20. [PMID: 33531396 PMCID: PMC7858054 DOI: 10.1128/mbio.02724-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/23/2020] [Indexed: 01/14/2023] Open
Abstract
In aquifers, acetylene (C2H2) is a product of abiotic degradation of trichloroethene (TCE) catalyzed by in situ minerals. C2H2 can, in turn, inhibit multiple microbial processes including TCE dechlorination and metabolisms that commonly support dechlorination, in addition to supporting the growth of acetylenotrophic microorganisms. Previously, C2H2 was shown to support TCE reductive dechlorination in synthetic, laboratory-constructed cocultures containing the acetylenotroph Pelobacter sp. strain SFB93 and Dehalococcoides mccartyi strain 195 or strain BAV1. In this study, we demonstrate TCE and perchloroethene (PCE) reductive dechlorination by a microbial community enriched from contaminated groundwater and amended with C2H2 as the sole electron donor and organic carbon source. The metagenome of the stable, enriched community was analyzed to elucidate putative community functions. A novel anaerobic acetylenotroph in the phylum Actinobacteria was identified using metagenomic analysis. These results demonstrate that the coupling of acetylenotrophy and reductive dechlorination can occur in the environment with native bacteria and broaden our understanding of biotransformation at contaminated sites containing both TCE and C2H2IMPORTANCE Understanding the complex metabolisms of microbial communities in contaminated groundwaters is a challenge. PCE and TCE are among the most common groundwater contaminants in the United States that, when exposed to certain minerals, exhibit a unique abiotic degradation pathway in which C2H2 is a product. C2H2 can act as both an inhibitor of TCE dechlorination and of supporting metabolisms and an energy source for acetylenotrophic bacteria. Here, we combine laboratory microcosm studies with computational approaches to enrich and characterize an environmental microbial community that couples two uncommon metabolisms, demonstrating unique metabolic interactions only yet reported in synthetic, laboratory-constructed settings. Using this comprehensive approach, we have identified the first reported anaerobic acetylenotroph in the phylum Actinobacteria, demonstrating the yet-undescribed diversity of this metabolism that is widely considered to be uncommon.
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Affiliation(s)
- Sara Gushgari-Doyle
- Department of Civil and Environmental Engineering, University of California, Berkeley, California, USA
| | | | - Ray Keren
- Department of Civil and Environmental Engineering, University of California, Berkeley, California, USA
- Department of Earth and Planetary Sciences, University of California, Berkeley, California, USA
| | | | | | - Jillian F Banfield
- Department of Earth and Planetary Sciences, University of California, Berkeley, California, USA
| | - Lisa Alvarez-Cohen
- Department of Civil and Environmental Engineering, University of California, Berkeley, California, USA
- Earth and Environmental Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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7
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Diazotrophic Anaeromyxobacter Isolates from Soils. Appl Environ Microbiol 2020; 86:AEM.00956-20. [PMID: 32532868 DOI: 10.1128/aem.00956-20] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/04/2020] [Indexed: 11/20/2022] Open
Abstract
Biological nitrogen fixation is an essential reaction in a major pathway for supplying nitrogen to terrestrial environments. Previous culture-independent analyses based on soil DNA/RNA/protein sequencing could globally detect the nitrogenase genes/proteins of Anaeromyxobacter (in the class Deltaproteobacteria), commonly distributed in soil environments and predominant in paddy soils; this suggests the importance of Anaeromyxobacter in nitrogen fixation in soil environments. However, direct experimental evidence is lacking; there has been no research on the genetic background and ability of Anaeromyxobacter to fix nitrogen. Therefore, we verified the diazotrophy of Anaeromyxobacter based on both genomic and culture-dependent analyses using Anaeromyxobacter sp. strains PSR-1 and Red267 isolated from soils. Based on the comparison of nif gene clusters, strains PSR-1 and Red267 as well as strains Fw109-5, K, and diazotrophic Geobacter and Pelobacter in the class Deltaproteobacteria contain the minimum set of genes for nitrogenase (nifBHDKEN). These results imply that Anaeromyxobacter species have the ability to fix nitrogen. In fact, Anaeromyxobacter PSR-1 and Red267 exhibited N2-dependent growth and acetylene reduction activity (ARA) in vitro Transcriptional activity of the nif gene was also detected when both strains were cultured with N2 gas as a sole nitrogen source, indicating that Anaeromyxobacter can fix and assimilate N2 gas by nitrogenase. In addition, PSR-1- or Red267-inoculated soil showed ARA activity and the growth of the inoculated strains on the basis of RNA-based analysis, demonstrating that Anaeromyxobacter can fix nitrogen in the paddy soil environment. Our study provides novel insights into the pivotal environmental function, i.e., nitrogen fixation, of Anaeromyxobacter, which is a common soil bacterium.IMPORTANCE Anaeromyxobacter is globally distributed in soil environments, especially predominant in paddy soils. Current studies based on environmental DNA/RNA analyses frequently detect gene fragments encoding nitrogenase of Anaeromyxobacter from various soil environments. Although the importance of Anaeromyxobacter as a diazotroph in nature has been suggested by culture-independent studies, there has been no solid evidence and validation from genomic and culture-based analyses that Anaeromyxobacter fixes nitrogen. This study demonstrates that Anaeromyxobacter harboring nitrogenase genes exhibits diazotrophic ability; moreover, N2-dependent growth was demonstrated in vitro and in the soil environment. Our findings indicate that nitrogen fixation is important for Anaeromyxobacter to survive under nitrogen-deficient environments and provide a novel insight into the environmental function of Anaeromyxobacter, which is a common bacterium in soils.
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8
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Genome-Resolved Metagenomics Extends the Environmental Distribution of the Verrucomicrobia Phylum to the Deep Terrestrial Subsurface. mSphere 2019; 4:4/6/e00613-19. [PMID: 31852806 PMCID: PMC6920513 DOI: 10.1128/msphere.00613-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Verrucomicrobia phylum of bacteria is widespread in many different ecosystems; however, its role in microbial communities remains poorly understood. Verrucomicrobia are often low-abundance community members, yet previous research suggests they play a major role in organic carbon degradation. While Verrucomicrobia remain poorly represented in culture collections, numerous genomes have been reconstructed from metagenomic data sets in recent years. The study of genomes from across the phylum allows for an extensive assessment of their potential ecosystem roles. The significance of this work is (i) the recovery of a novel genus of Verrucomicrobia from 2.3 km in the subsurface with the ability to withstand the extreme conditions that characterize this environment, and (ii) the most extensive assessment of ecophysiological traits encoded by Verrucomicrobia genomes to date. We show that members of this phylum are specialist organic polymer degraders that can withstand a wider range of environmental conditions than previously thought. Bacteria of the phylum Verrucomicrobia are prevalent and are particularly common in soil and freshwater environments. Their cosmopolitan distribution and reported capacity for polysaccharide degradation suggests members of Verrucomicrobia are important contributors to carbon cycling across Earth’s ecosystems. Despite their prevalence, the Verrucomicrobia are underrepresented in isolate collections and genome databases; consequently, their ecophysiological roles may not be fully realized. Here, we expand genomic sampling of the Verrucomicrobia phylum by describing a novel genus, “Candidatus Marcellius,” belonging to the order Opitutales. “Ca. Marcellius” was recovered from a shale-derived produced fluid metagenome collected 313 days after hydraulic fracturing, the deepest environment from which a member of the Verrucomicrobia has been recovered to date. We uncover genomic attributes that may explain the capacity of this organism to inhabit a shale gas well, including the potential for utilization of organic polymers common in hydraulic fracturing fluids, nitrogen fixation, adaptation to high salinities, and adaptive immunity via CRISPR-Cas. To illuminate the phylogenetic and environmental distribution of these metabolic and adaptive traits across the Verrucomicrobia phylum, we performed a comparative genomic analysis of 31 publicly available, nearly complete Verrucomicrobia genomes. Our genomic findings extend the environmental distribution of the Verrucomicrobia 2.3 kilometers into the terrestrial subsurface. Moreover, we reveal traits widely encoded across members of the Verrucomicrobia, including the capacity to degrade hemicellulose and to adapt to physical and biological environmental perturbations, thereby contributing to the expansive habitat range reported for this phylum. IMPORTANCE The Verrucomicrobia phylum of bacteria is widespread in many different ecosystems; however, its role in microbial communities remains poorly understood. Verrucomicrobia are often low-abundance community members, yet previous research suggests they play a major role in organic carbon degradation. While Verrucomicrobia remain poorly represented in culture collections, numerous genomes have been reconstructed from metagenomic data sets in recent years. The study of genomes from across the phylum allows for an extensive assessment of their potential ecosystem roles. The significance of this work is (i) the recovery of a novel genus of Verrucomicrobia from 2.3 km in the subsurface with the ability to withstand the extreme conditions that characterize this environment, and (ii) the most extensive assessment of ecophysiological traits encoded by Verrucomicrobia genomes to date. We show that members of this phylum are specialist organic polymer degraders that can withstand a wider range of environmental conditions than previously thought.
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9
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Nash MV, Anesio AM, Barker G, Tranter M, Varliero G, Eloe-Fadrosh EA, Nielsen T, Turpin-Jelfs T, Benning LG, Sánchez-Baracaldo P. Metagenomic insights into diazotrophic communities across Arctic glacier forefields. FEMS Microbiol Ecol 2019; 94:5036517. [PMID: 29901729 PMCID: PMC6054269 DOI: 10.1093/femsec/fiy114] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 06/11/2018] [Indexed: 11/30/2022] Open
Abstract
Microbial nitrogen fixation is crucial for building labile nitrogen stocks and facilitating higher plant colonisation in oligotrophic glacier forefield soils. Here, the diazotrophic bacterial community structure across four Arctic glacier forefields was investigated using metagenomic analysis. In total, 70 soil metagenomes were used for taxonomic interpretation based on 185 nitrogenase (nif) sequences, extracted from assembled contigs. The low number of recovered genes highlights the need for deeper sequencing in some diverse samples, to uncover the complete microbial populations. A key group of forefield diazotrophs, found throughout the forefields, was identified using a nifH phylogeny, associated with nifH Cluster I and III. Sequences related most closely to groups including Alphaproteobacteria, Betaproteobacteria, Cyanobacteria and Firmicutes. Using multiple nif genes in a Last Common Ancestor analysis revealed a diverse range of diazotrophs across the forefields. Key organisms identified across the forefields included Nostoc, Geobacter, Polaromonas and Frankia. Nitrogen fixers that are symbiotic with plants were also identified, through the presence of root associated diazotrophs, which fix nitrogen in return for reduced carbon. Additional nitrogen fixers identified in forefield soils were metabolically diverse, including fermentative and sulphur cycling bacteria, halophiles and anaerobes.
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Affiliation(s)
- Maisie V Nash
- School of Geographical Sciences, University of Bristol, UK
| | | | - Gary Barker
- School of Life Sciences, University of Bristol, UK
| | - Martyn Tranter
- School of Geographical Sciences, University of Bristol, UK
| | | | | | - Torben Nielsen
- DOE Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA 94598, US
| | | | - Liane G Benning
- GFZ German Research Centre for Geosciences, Telegrafenenberg, 14473 Potsdam, Germany.,School of Earth and Environment, University of Leeds, LS2 9JT, Leeds, UK.,Department of Earth Sciences, Free University of Berlin, Malteserstr, 74-100, Building A, 12249, Berlin, Germany
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10
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Akob DM, Sutton JM, Fierst JL, Haase KB, Baesman S, Luther GW, Miller LG, Oremland RS. Acetylenotrophy: a hidden but ubiquitous microbial metabolism? FEMS Microbiol Ecol 2018; 94:5026170. [PMID: 29933435 PMCID: PMC7190893 DOI: 10.1093/femsec/fiy103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/29/2018] [Indexed: 11/12/2022] Open
Abstract
Acetylene (IUPAC name: ethyne) is a colorless, gaseous hydrocarbon, composed of two triple bonded carbon atoms attached to hydrogens (C2H2). When microbiologists and biogeochemists think of acetylene, they immediately think of its use as an inhibitory compound of certain microbial processes and a tracer for nitrogen fixation. However, what is less widely known is that anaerobic and aerobic microorganisms can degrade acetylene, using it as a sole carbon and energy source and providing the basis of a microbial food web. Here, we review what is known about acetylene degrading organisms and introduce the term 'acetylenotrophs' to refer to the microorganisms that carry out this metabolic pathway. In addition, we review the known environmental sources of acetylene and postulate the presence of an hidden acetylene cycle. The abundance of bacteria capable of using acetylene and other alkynes as an energy and carbon source suggests that there are energy cycles present in the environment that are driven by acetylene and alkyne production and consumption that are isolated from atmospheric exchange. Acetylenotrophs may have developed to leverage the relatively high concentrations of acetylene in the pre-Cambrian atmosphere, evolving later to survive in specialized niches where acetylene and other alkynes were produced.
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Affiliation(s)
- Denise M Akob
- U. S. Geological Survey, 12201 Sunrise Valley Dr, MS 430, Reston, VA 20192 USA
| | - John M Sutton
- Department of Biological Sciences, The University of Alabama, SEC 2328, Box 870344, Tuscaloosa, AL 35487 USA
| | - Janna L Fierst
- Department of Biological Sciences, The University of Alabama, SEC 2328, Box 870344, Tuscaloosa, AL 35487 USA
| | - Karl B Haase
- U. S. Geological Survey, 12201 Sunrise Valley Dr, MS 430, Reston, VA 20192 USA
| | - Shaun Baesman
- U. S. Geological Survey, 345 Middlefield Road, MS 480, Menlo Park, CA 94025 USA
| | - George W Luther
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Road, Cannon Laboratory 218, Lewes, DE 19958, USA
| | - Laurence G Miller
- U. S. Geological Survey, 345 Middlefield Road, MS 480, Menlo Park, CA 94025 USA
| | - Ronald S Oremland
- U. S. Geological Survey, 345 Middlefield Road, MS 480, Menlo Park, CA 94025 USA
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