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Kim M, Cha IT, Li M, Park SJ. Unraveling interspecies cross-feeding during anaerobic lignin degradation for bioenergy applications. CHEMOSPHERE 2024; 361:142588. [PMID: 38866340 DOI: 10.1016/j.chemosphere.2024.142588] [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: 04/30/2024] [Revised: 06/04/2024] [Accepted: 06/10/2024] [Indexed: 06/14/2024]
Abstract
Lignin, a major component of plant biomass, remains underutilized for renewable biofuels due to its complex and heterogeneous structure. Although investigations into depolymerizing lignin using fungi are well-established, studies of microbial pathways that enable anaerobic lignin breakdown linked with methanogenesis are limited. Through an enrichment cultivation approach with inoculation of freshwater sediment, we enriched a microbial community capable of producing methane during anaerobic lignin degradation. We reconstructed the near-complete population genomes of key lignin degraders and methanogens using metagenome-assembled genomes finally selected in this study (MAGs; 92 bacterial and 4 archaeal MAGs affiliated into 45 and 2 taxonomic groups, respectively). This study provides genetic evidence of microbial interdependence in conversion of lignin to methane in a syntrophic community. Metagenomic analysis revealed metabolic linkages, with lignin-hydrolyzing and/or fermentative bacteria such as the genera Alkalibaculum and Propionispora transforming lignin breakdown products into compounds such as acetate to feed methanogens (two archaeal MAGs classified into the genus Methanosarcina or UBA6 of the family Methanomassiliicoccaceae). Understanding the synergistic relationships between microbes that convert lignin could inform strategies for producing renewable bioenergy and treating aromatic-contaminated environments through anaerobic biodegradation processes. Overall, this study offers fundamental insights into complex community-level anaerobic lignin metabolism, highlighting hitherto unknown players, interactions, and pathways in this biotechnologically valuable process.
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Affiliation(s)
- Minji Kim
- Department of Biology, Jeju National University, 102 Jejudaehak-ro, Jeju, 63243, South Korea
| | - In-Tae Cha
- Climate Change and Environmental Biology Research Division, National Institute of Biological Resources, Incheon, 22689, South Korea
| | - Meng Li
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Soo-Je Park
- Department of Biology, Jeju National University, 102 Jejudaehak-ro, Jeju, 63243, South Korea.
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2
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Brabender M, Henriques Pereira DP, Mrnjavac N, Schlikker ML, Kimura ZI, Sucharitakul J, Kleinermanns K, Tüysüz H, Buckel W, Preiner M, Martin WF. Ferredoxin reduction by hydrogen with iron functions as an evolutionary precursor of flavin-based electron bifurcation. Proc Natl Acad Sci U S A 2024; 121:e2318969121. [PMID: 38513105 PMCID: PMC7615787 DOI: 10.1073/pnas.2318969121] [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: 10/31/2023] [Accepted: 02/14/2024] [Indexed: 03/23/2024] Open
Abstract
Autotrophic theories for the origin of metabolism posit that the first cells satisfied their carbon needs from CO2 and were chemolithoautotrophs that obtained their energy and electrons from H2. The acetyl-CoA pathway of CO2 fixation is central to that view because of its antiquity: Among known CO2 fixing pathways it is the only one that is i) exergonic, ii) occurs in both bacteria and archaea, and iii) can be functionally replaced in full by single transition metal catalysts in vitro. In order to operate in cells at a pH close to 7, however, the acetyl-CoA pathway requires complex multi-enzyme systems capable of flavin-based electron bifurcation that reduce low potential ferredoxin-the physiological donor of electrons in the acetyl-CoA pathway-with electrons from H2. How can the acetyl-CoA pathway be primordial if it requires flavin-based electron bifurcation? Here, we show that native iron (Fe0), but not Ni0, Co0, Mo0, NiFe, Ni2Fe, Ni3Fe, or Fe3O4, promotes the H2-dependent reduction of aqueous Clostridium pasteurianum ferredoxin at pH 8.5 or higher within a few hours at 40 °C, providing the physiological function of flavin-based electron bifurcation, but without the help of enzymes or organic redox cofactors. H2-dependent ferredoxin reduction by iron ties primordial ferredoxin reduction and early metabolic evolution to a chemical process in the Earth's crust promoted by solid-state iron, a metal that is still deposited in serpentinizing hydrothermal vents today.
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Affiliation(s)
- Max Brabender
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf40225, Germany
| | - Delfina P. Henriques Pereira
- Microcosm Earth Center, Research Group for Geochemical Protozymes, Max Planck Institute for Terrestrial Microbiology and Philipps University, Marburg35032, Germany
| | - Natalia Mrnjavac
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf40225, Germany
| | - Manon Laura Schlikker
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf40225, Germany
| | - Zen-Ichiro Kimura
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf40225, Germany
- Department of Civil and Environmental Engineering, National Institute of Technology, Kure College, Kure, Hiroshima737-8506, Japan
| | - Jeerus Sucharitakul
- Department of Biochemistry, Chulalongkorn University, Patumwan, Bangkok10330, Thailand
| | - Karl Kleinermanns
- Institute for Physical Chemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf40225, Germany
| | - Harun Tüysüz
- Max Planck Institute for Coal Research, Department of Heterogeneous Catalysis, Mülheim an der Ruhr45470, Germany
| | - Wolfgang Buckel
- Max Planck Institute for Terrestrial Microbiology, Marburg35043, Germany
- Laboratory for Microbiology, Department of Biology, Philipps University, Marburg35043, Germany
- Center for Synthetic Microbiology SYNMIKRO, Philipps University, Marburg35043, Germany
| | - Martina Preiner
- Microcosm Earth Center, Research Group for Geochemical Protozymes, Max Planck Institute for Terrestrial Microbiology and Philipps University, Marburg35032, Germany
| | - William F. Martin
- Institute of Molecular Evolution, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf40225, Germany
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3
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Ciric M, Šaraba V, Budin C, de Boer T, Nikodinovic-Runic J. Polyurethane-Degrading Potential of Alkaline Groundwater Bacteria. MICROBIAL ECOLOGY 2023; 87:21. [PMID: 38153543 DOI: 10.1007/s00248-023-02338-z] [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: 09/08/2023] [Accepted: 12/24/2023] [Indexed: 12/29/2023]
Abstract
Plastic waste is a global environmental burden and long-lasting plastic polymers, including ubiquitous and toxic polyurethanes (PUs), rapidly accumulate in the water environments. In this study, samples were collected from the three alkaline groundwater occurrences in the geotectonic regions of the Pannonian basin of northern Serbia (Torda and Slankamen Banja) and Inner Dinarides of western Serbia (Mokra Gora) with aim to isolate and identify bacteria with plastic- and lignocellulose-degrading potential, that could be applied to reduce the burden of environmental plastic pollution. The investigated occurrences belong to cold, mildly alkaline (pH: 7.6-7.9) brackish and hyperalkaline (pH: 11.5) fresh groundwaters of the SO4 - Na + K, Cl - Na + K and OH, Cl - Ca, Na + K genetic type. Full-length 16S rDNA sequencing, using Oxford Nanopore sequencing device, was performed with DNA extracted from colonies obtained by cultivation of all groundwater samples, as well as with DNA extracted directly from one groundwater sample. The most abundant genera belong to Pseudomonas, Acidovorax, Kocuria and Methylotenera. All screened isolates (100%) had the ability to grow on at least 3 of the tested plastic and lignocellulosic substrates, with 53.9% isolates degrading plastic substrate Impranil® DLN-SD (SD), a model compound for PUs degradation. Isolates degrading SD that were identified by partial 16S rDNA sequencing belong to the Stenotrophomonas, Pseudomonas, Paraburkholderia, Aeromonas, Vibrio and Acidovorax genera. Taking into account that plastics, including commonly produced PUs, are widespread in groundwater, identification of PUs-degrading bacteria may have potential applications in bioremediation of groundwater polluted with this polymer.
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Affiliation(s)
- Milica Ciric
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia.
| | - Vladimir Šaraba
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Clémence Budin
- Microlife Solutions, Science Park 406, 1098XH, Amsterdam, The Netherlands
| | - Tjalf de Boer
- Microlife Solutions, Science Park 406, 1098XH, Amsterdam, The Netherlands
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4
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Schwander L, Brabender M, Mrnjavac N, Wimmer JLE, Preiner M, Martin WF. Serpentinization as the source of energy, electrons, organics, catalysts, nutrients and pH gradients for the origin of LUCA and life. Front Microbiol 2023; 14:1257597. [PMID: 37854333 PMCID: PMC10581274 DOI: 10.3389/fmicb.2023.1257597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/04/2023] [Indexed: 10/20/2023] Open
Abstract
Serpentinization in hydrothermal vents is central to some autotrophic theories for the origin of life because it generates compartments, reductants, catalysts and gradients. During the process of serpentinization, water circulates through hydrothermal systems in the crust where it oxidizes Fe (II) in ultramafic minerals to generate Fe (III) minerals and H2. Molecular hydrogen can, in turn, serve as a freely diffusible source of electrons for the reduction of CO2 to organic compounds, provided that suitable catalysts are present. Using catalysts that are naturally synthesized in hydrothermal vents during serpentinization H2 reduces CO2 to formate, acetate, pyruvate, and methane. These compounds represent the backbone of microbial carbon and energy metabolism in acetogens and methanogens, strictly anaerobic chemolithoautotrophs that use the acetyl-CoA pathway of CO2 fixation and that inhabit serpentinizing environments today. Serpentinization generates reduced carbon, nitrogen and - as newer findings suggest - reduced phosphorous compounds that were likely conducive to the origins process. In addition, it gives rise to inorganic microcompartments and proton gradients of the right polarity and of sufficient magnitude to support chemiosmotic ATP synthesis by the rotor-stator ATP synthase. This would help to explain why the principle of chemiosmotic energy harnessing is more conserved (older) than the machinery to generate ion gradients via pumping coupled to exergonic chemical reactions, which in the case of acetogens and methanogens involve H2-dependent CO2 reduction. Serpentinizing systems exist in terrestrial and deep ocean environments. On the early Earth they were probably more abundant than today. There is evidence that serpentinization once occurred on Mars and is likely still occurring on Saturn's icy moon Enceladus, providing a perspective on serpentinization as a source of reductants, catalysts and chemical disequilibrium for life on other worlds.
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Affiliation(s)
- Loraine Schwander
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Max Brabender
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Natalia Mrnjavac
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Jessica L. E. Wimmer
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Martina Preiner
- Microcosm Earth Center, Max Planck Institute for Terrestrial Microbiology and Philipps-Universität, Marburg, Germany
| | - William F. Martin
- Institute of Molecular Evolution, Biology Department, Math. -Nat. Faculty, Heinrich-Heine-Universität, Düsseldorf, Germany
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5
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Popall RM, Postec A, Lecoeuvre A, Quéméneur M, Erauso G. Metabolic challenges and key players in serpentinite-hosted microbial ecosystems. Front Microbiol 2023; 14:1197823. [PMID: 37555067 PMCID: PMC10404738 DOI: 10.3389/fmicb.2023.1197823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/29/2023] [Indexed: 08/10/2023] Open
Abstract
Serpentinite-hosted systems are amongst the most challenging environments for life on Earth. Serpentinization, a geochemical alteration of exposed ultramafic rock, produces hydrothermal fluids enriched in abiotically derived hydrogen (H2), methane (CH4), and small organic molecules. The hyperalkaline pH of these fluids poses a great challenge for metabolic energy and nutrient acquisition, curbing the cellular membrane potential and limiting electron acceptor, carbon, and phosphorous availability. Nevertheless, serpentinization supports the growth of diverse microbial communities whose metabolic make-up might shed light on the beginning of life on Earth and potentially elsewhere. Here, we outline current hypotheses on metabolic energy production, carbon fixation, and nutrient acquisition in serpentinizing environments. A taxonomic survey is performed for each important metabolic function, highlighting potential key players such as H2 and CH4 cycling Serpentinimonas, Hydrogenophaga, Methanobacteriales, Methanosarcinales, and novel candidate phyla. Methodological biases of the available data and future approaches are discussed.
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Affiliation(s)
| | | | | | | | - Gaël Erauso
- Aix-Marseille Univ, Univ Toulon, CNRS, IRD, MIO, Marseille, France
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6
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Thieringer PH, Boyd ES, Templeton AS, Spear JR. Metapangenomic investigation provides insight into niche differentiation of methanogenic populations from the subsurface serpentinizing environment, Samail Ophiolite, Oman. Front Microbiol 2023; 14:1205558. [PMID: 37465028 PMCID: PMC10350532 DOI: 10.3389/fmicb.2023.1205558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/13/2023] [Indexed: 07/20/2023] Open
Abstract
Serpentinization reactions produce highly reduced waters that have hyperalkaline pH and that can have high concentrations of H2 and CH4. Putatively autotrophic methanogenic archaea have been identified in the subsurface waters of the Samail Ophiolite, Sultanate of Oman, though the strategies to overcome hyperalkaline pH and dissolved inorganic carbon limitation remain to be fully understood. Here, we recovered metagenome assembled genomes (MAGs) and applied a metapangenomic approach to three different Methanobacterium populations to assess habitat-specific functional gene distribution. A Type I population was identified in the fluids with neutral pH, while a Type II and "Mixed" population were identified in the most hyperalkaline fluids (pH 11.63). The core genome of all Methanobacterium populations highlighted potential DNA scavenging techniques to overcome phosphate or nitrogen limitation induced by environmental conditions. With particular emphasis on the Mixed and Type II population found in the most hyperalkaline fluids, the accessory genomes unique to each population reflected adaptation mechanisms suggesting lifestyles that minimize niche overlap. In addition to previously reported metabolic capability to utilize formate as an electron donor and generate intracellular CO2, the Type II population possessed genes relevant to defense against antimicrobials and assimilating potential osmoprotectants to provide cellular stability. The accessory genome of the Mixed population was enriched in genes for multiple glycosyltransferases suggesting reduced energetic costs by adhering to mineral surfaces or to other microorganisms, and fostering a non-motile lifestyle. These results highlight the niche differentiation of distinct Methanobacterium populations to circumvent the challenges of serpentinization impacted fluids through coexistence strategies, supporting our ability to understand controls on methanogenic lifestyles and adaptations within the serpentinizing subsurface fluids of the Samail Ophiolite.
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Affiliation(s)
- Patrick H. Thieringer
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
| | - Eric S. Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Alexis S. Templeton
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - John R. Spear
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
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7
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Trutschel LR, Kruger BR, Sackett JD, Chadwick GL, Rowe AR. Determining resident microbial community members and their correlations with geochemistry in a serpentinizing spring. Front Microbiol 2023; 14:1182497. [PMID: 37396382 PMCID: PMC10308030 DOI: 10.3389/fmicb.2023.1182497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/24/2023] [Indexed: 07/04/2023] Open
Abstract
Terrestrial serpentinizing systems allow us insight into the realm of alkaliphilic microbial communities driven by geology in a way that is frequently more accessible than their deep subsurface or marine counterparts. However, these systems are also marked by geochemical and microbial community variation due to the interactions of serpentinized fluids with host geology and the surface environment. To separate the transient from the endemic microbes in a hyperalkaline environment, we assessed the Ney Springs terrestrial serpentinizing system microbial community and geochemistry at six time points over the span of a year. Using 16S rRNA gene surveys we observed 93 amplicon sequence variants (ASVs) that were found at every sampling event. This is compared to ~17,000 transient ASVs that were detected only once across the six sampling events. Of the resident community members, 16 of these ASVs were regularly greater than 1% of the community during every sampling period. Additionally, many of these core taxa experienced statistically significant changes in relative abundance with time. Variation in the abundance of some core populations correlated with geochemical variation. For example, members of the Tindallia group, showed a positive correlation with variation in levels of ammonia at the spring. Investigating the metagenome assembled genomes of these microbes revealed evidence of the potential for ammonia generation via Stickland reactions within Tindallia. This observation offers new insight into the origin of high ammonia concentrations (>70 mg/L) seen at this site. Similarly, the abundance of putative sulfur-oxidizing microbes like Thiomicrospira, Halomonas, and a Rhodobacteraceae species could be linked to changes observed in sulfur-oxidation intermediates like tetrathionate and thiosulfate. While these data supports the influence of core microbial community members on a hyperalkaline spring's geochemistry, there is also evidence that subsurface processes affect geochemistry and may impact community dynamics as well. Though the physiology and ecology of these astrobiologically relevant ecosystems are still being uncovered, this work helps identify a stable microbial community that impacts spring geochemistry in ways not previously observed in serpentinizing ecosystems.
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Affiliation(s)
- Leah R. Trutschel
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Brittany R. Kruger
- Division of Hydrologic Sciences, Desert Research Institute, Las Vegas, Las Vegas, NV, United States
| | - Joshua D. Sackett
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Grayson L. Chadwick
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Annette R. Rowe
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
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8
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Russell MJ. A self-sustaining serpentinization mega-engine feeds the fougerite nanoengines implicated in the emergence of guided metabolism. Front Microbiol 2023; 14:1145915. [PMID: 37275164 PMCID: PMC10236563 DOI: 10.3389/fmicb.2023.1145915] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/22/2023] [Indexed: 06/07/2023] Open
Abstract
The demonstration by Ivan Barnes et al. that the serpentinization of fresh Alpine-type ultramafic rocks results in the exhalation of hot alkaline fluids is foundational to the submarine alkaline vent theory (AVT) for life's emergence to its 'improbable' thermodynamic state. In AVT, such alkaline fluids ≤ 150°C, bearing H2 > CH4 > HS--generated and driven convectively by a serpentinizing exothermic mega-engine operating in the ultramafic crust-exhale into the iron-rich, CO2> > > NO3--bearing Hadean ocean to result in hydrothermal precipitate mounds comprising macromolecular ferroferric-carbonate oxyhydroxide and minor sulfide. As the nanocrystalline minerals fougerite/green rust and mackinawite (FeS), they compose the spontaneously precipitated inorganic membranes that keep the highly contrasting solutions apart, thereby maintaining redox and pH disequilibria. They do so in the form of fine chimneys and chemical gardens. The same disequilibria drive the reduction of CO2 to HCOO- or CO, and the oxidation of CH4 to a methyl group-the two products reacting to form acetate in a sequence antedating the 'energy-producing' acetyl coenzyme-A pathway. Fougerite is a 2D-layered mineral in which the hydrous interlayers themselves harbor 2D solutions, in effect constricted to ~ 1D by preferentially directed electron hopping/tunneling, and proton Gröthuss 'bucket-brigading' when subject to charge. As a redox-driven nanoengine or peristaltic pump, fougerite forces the ordered reduction of nitrate to ammonium, the amination of pyruvate and oxalate to alanine and glycine, and their condensation to short peptides. In turn, these peptides have the flexibility to sequester the founding inorganic iron oxyhydroxide, sulfide, and pyrophosphate clusters, to produce metal- and phosphate-dosed organic films and cells. As the feed to the hydrothermal mound fails, the only equivalent sustenance on offer to the first autotrophs is the still mildly serpentinizing upper crust beneath. While the conditions here are very much less bountiful, they do offer the similar feed and disequilibria the survivors are accustomed to. Sometime during this transition, a replicating non-ribosomal guidance system is discovered to provide the rules to take on the incrementally changing surroundings. The details of how these replicating apparatuses emerged are the hard problem, but by doing so the progenote archaea and bacteria could begin to colonize what would become the deep biosphere. Indeed, that the anaerobic nitrate-respiring methanotrophic archaea and the deep-branching Acetothermia presently comprise a portion of that microbiome occupying serpentinizing rocks offers circumstantial support for this notion. However, the inescapable, if jarring conclusion is drawn that, absent fougerite/green rust, there would be no structured channelway to life.
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Affiliation(s)
- Michael J. Russell
- Dipartimento di Chimica, Università degli Studi di Torino, Torino, Italy
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9
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Howells AEG, De Martini F, Gile GH, Shock EL. An examination of protist diversity in serpentinization-hosted ecosystems of the Samail Ophiolite of Oman. Front Microbiol 2023; 14:1139333. [PMID: 37213519 PMCID: PMC10192764 DOI: 10.3389/fmicb.2023.1139333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/30/2023] [Indexed: 05/23/2023] Open
Abstract
In the Samail Ophiolite of Oman, the geological process of serpentinization produces reduced, hydrogen rich, hyperalkaline (pH > 11) fluids. These fluids are generated through water reacting with ultramafic rock from the upper mantle in the subsurface. On Earth's continents, serpentinized fluids can be expressed at the surface where they can mix with circumneutral surface water and subsequently generate a pH gradient (∼pH 8 to pH > 11) in addition to variations in other chemical parameters such as dissolved CO2, O2, and H2. Globally, archaeal and bacterial community diversity has been shown to reflect geochemical gradients established by the process of serpentinization. It is unknown if the same is true for microorganisms of the domain Eukarya (eukaryotes). In this study, using 18S rRNA gene amplicon sequencing, we explore the diversity of microbial eukaryotes called protists in sediments of serpentinized fluids in Oman. We demonstrate that protist community composition and diversity correlate significantly with variations in pH, with protist richness being significantly lower in sediments of hyperalkaline fluids. In addition to pH, the availability of CO2 to phototrophic protists, the composition of potential food sources (prokaryotes) for heterotrophic protists and the concentration of O2 for anaerobic protists are factors that likely shape overall protist community composition and diversity along the geochemical gradient. The taxonomy of the protist 18S rRNA gene sequences indicates the presence of protists that are involved in carbon cycling in serpentinized fluids of Oman. Therefore, as we evaluate the applicability of serpentinization for carbon sequestration, the presence and diversity of protists should be considered.
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Affiliation(s)
- Alta E. G. Howells
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Francesca De Martini
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
- Mesa Community College, Mesa, AZ, United States
| | - Gillian H. Gile
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, United States
| | - Everett L. Shock
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, United States
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States
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10
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Seyler LM, Kraus EA, McLean C, Spear JR, Templeton AS, Schrenk MO. An untargeted exometabolomics approach to characterize dissolved organic matter in groundwater of the Samail Ophiolite. Front Microbiol 2023; 14:1093372. [PMID: 36970670 PMCID: PMC10033605 DOI: 10.3389/fmicb.2023.1093372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/23/2023] [Indexed: 03/11/2023] Open
Abstract
The process of serpentinization supports life on Earth and gives rise to the habitability of other worlds in our Solar System. While numerous studies have provided clues to the survival strategies of microbial communities in serpentinizing environments on the modern Earth, characterizing microbial activity in such environments remains challenging due to low biomass and extreme conditions. Here, we used an untargeted metabolomics approach to characterize dissolved organic matter in groundwater in the Samail Ophiolite, the largest and best characterized example of actively serpentinizing uplifted ocean crust and mantle. We found that dissolved organic matter composition is strongly correlated with both fluid type and microbial community composition, and that the fluids that were most influenced by serpentinization contained the greatest number of unique compounds, none of which could be identified using the current metabolite databases. Using metabolomics in conjunction with metagenomic data, we detected numerous products and intermediates of microbial metabolic processes and identified potential biosignatures of microbial activity, including pigments, porphyrins, quinones, fatty acids, and metabolites involved in methanogenesis. Metabolomics techniques like the ones used in this study may be used to further our understanding of life in serpentinizing environments, and aid in the identification of biosignatures that can be used to search for life in serpentinizing systems on other worlds.
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Affiliation(s)
- Lauren M. Seyler
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, United States
- Biology Program, School of Natural Sciences and Mathematics, Stockton University, Galloway, NJ, United States
- Blue Marble Space Institute of Science, Seattle, WA, United States
- *Correspondence: Lauren M. Seyler,
| | - Emily A. Kraus
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
- Department of Environmental Engineering, University of Colorado, Boulder, Boulder, CO, United States
| | - Craig McLean
- Massachusetts Institute of Technology, Cambridge, MA, United States
| | - John R. Spear
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
| | - Alexis S. Templeton
- Department of Geological Sciences, University of Colorado, Boulder, Boulder, CO, United States
| | - Matthew O. Schrenk
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, MI, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
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11
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Fu L, Lai S, Zhou Z, Chen Z, Cheng L. Seasonal variation of microbial community and methane metabolism in coalbed water in the Erlian Basin, China. Front Microbiol 2023; 14:1114201. [PMID: 36846781 PMCID: PMC9953142 DOI: 10.3389/fmicb.2023.1114201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/26/2023] [Indexed: 02/12/2023] Open
Abstract
Coalbed water is a semi-open system connecting underground coalbeds with the external environment. Microorganisms in coalbed water play an important role in coal biogasification and the carbon cycle. The community assemblages of microorganisms in such a dynamic system are not well understood. Here, we used high-throughput sequencing and metagenomic analysis to investigate microbial community structure and identify the potential functional microorganisms involved in methane metabolism in coalbed water in the Erlian Basin, a preferred low-rank coal bed methane (CBM) exploration and research area in China. The results showed that there were differences in the responses of bacteria and archaea to seasonal variation. Bacterial community structure was affected by seasonal variation but archaea was not. Methane oxidation metabolism dominated by Methylomonas and methanogenesis metabolism dominated by Methanobacterium may exist simultaneously in coalbed water.
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Affiliation(s)
- Li Fu
- Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Shouchao Lai
- Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Zhuo Zhou
- Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Zhenhong Chen
- Research Institute of Petroleum Exploration and Development, Beijing, China,*Correspondence: Zhenhong Chen, ✉
| | - Lei Cheng
- Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China,Lei Cheng, ✉
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12
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Unique H 2-utilizing lithotrophy in serpentinite-hosted systems. THE ISME JOURNAL 2023; 17:95-104. [PMID: 36207493 PMCID: PMC9751293 DOI: 10.1038/s41396-022-01197-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 01/08/2022] [Accepted: 01/17/2022] [Indexed: 11/08/2022]
Abstract
Serpentinization of ultramafic rocks provides molecular hydrogen (H2) that can support lithotrophic metabolism of microorganisms, but also poses extremely challenging conditions, including hyperalkalinity and limited electron acceptor availability. Investigation of two serpentinization-active systems reveals that conventional H2-/CO2-dependent homoacetogenesis is thermodynamically unfavorable in situ due to picomolar CO2 levels. Through metagenomics and thermodynamics, we discover unique taxa capable of metabolism adapted to the habitat. This included a novel deep-branching phylum, "Ca. Lithacetigenota", that exclusively inhabits serpentinite-hosted systems and harbors genes encoding alternative modes of H2-utilizing lithotrophy. Rather than CO2, these putative metabolisms utilize reduced carbon compounds detected in situ presumably serpentinization-derived: formate and glycine. The former employs a partial homoacetogenesis pathway and the latter a distinct pathway mediated by a rare selenoprotein-the glycine reductase. A survey of microbiomes shows that glycine reductases are diverse and nearly ubiquitous in serpentinite-hosted environments. "Ca. Lithacetigenota" glycine reductases represent a basal lineage, suggesting that catabolic glycine reduction is an ancient bacterial innovation by Terrabacteria for gaining energy from geogenic H2 even under hyperalkaline, CO2-poor conditions. Unique non-CO2-reducing metabolisms presented here shed light on potential strategies that extremophiles may employ for overcoming a crucial obstacle in serpentinization-associated environments, features potentially relevant to primordial lithotrophy in early Earth.
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13
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Munro-Ehrlich M, Nothaft DB, Fones EM, Matter JM, Templeton AS, Boyd ES. Parapatric speciation of Meiothermus in serpentinite-hosted aquifers in Oman. Front Microbiol 2023; 14:1138656. [PMID: 37125170 PMCID: PMC10130571 DOI: 10.3389/fmicb.2023.1138656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/27/2023] [Indexed: 05/02/2023] Open
Abstract
The factors that control the distribution and evolution of microbial life in subsurface environments remain enigmatic due to challenges associated with sampling fluids from discrete depth intervals via boreholes while avoiding mixing of fluids. Here, using an inflatable packer system, fracture waters were isolated and collected from three discrete depth intervals spanning >130 m in a borehole intersecting an ultramafic rock formation undergoing serpentinization in the Samail Ophiolite, Sultanate of Oman. Near surface aquifer waters were moderately reducing and had alkaline pH while deeper aquifer waters were reduced and had hyperalkaline pH, indicating extensive influence by serpentinization. Metagenomic sequencing and analysis of DNA from filtered biomass collected from discrete depth intervals revealed an abundance of aerobes in near surface waters and a greater proportion of anaerobes at depth. Yet the abundance of the putatively obligate aerobe, Meiothermus, increased with depth, providing an opportunity to evaluate the influence of chemical and spatial variation on its distribution and speciation. Two clades of Meiothermus metagenome assembled genomes (MAGs) were identified that correspond to surface and deep populations termed Types I (S) and II (D), respectively; both clades comprised an apparently Oman-specific lineage indicating a common ancestor. Type II (D) clade MAGs encoded fewer genes and were undergoing slower genome replication as inferred from read mapping. Further, single nucleotide variants (SNVs) and mobile genetic elements identified among MAGs revealed detectable, albeit limited, evidence for gene flow/recombination between spatially segregated Type I (S) and Type II (D) populations. Together, these observations indicate that chemical variation generated by serpentinization, combined with physical barriers that reduce/limit dispersal and gene flow, allowed for the parapatric speciation of Meiothermus in the Samail Ophiolite or a geologic precursor. Further, Meiothermus genomic data suggest that deep and shallow aquifer fluids in the Samail Ophiolite may mix over shorter time scales than has been previously estimated from geochemical data.
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Affiliation(s)
- Mason Munro-Ehrlich
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Daniel B. Nothaft
- Department of Geosciences, University of Colorado, Boulder, Boulder, CO, United States
| | - Elizabeth M. Fones
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Juerg M. Matter
- School of Ocean and Earth Science, University of Southampton, Southampton, United Kingdom
| | - Alexis S. Templeton
- Department of Geosciences, University of Colorado, Boulder, Boulder, CO, United States
| | - Eric S. Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
- *Correspondence: Eric S. Boyd,
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14
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Boyd ES, Spietz RL, Kour M, Colman DR. A naturalist perspective of microbiology: Examples from methanogenic archaea. Environ Microbiol 2023; 25:184-198. [PMID: 36367391 DOI: 10.1111/1462-2920.16285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
Storytelling has been the primary means of knowledge transfer over human history. The effectiveness and reach of stories are improved when the message is appropriate for the target audience. Oftentimes, the stories that are most well received and recounted are those that have a clear purpose and that are told from a variety of perspectives that touch on the varied interests of the target audience. Whether scientists realize or not, they are accustomed to telling stories of their own scientific discoveries through the preparation of manuscripts, presentations, and lectures. Perhaps less frequently, scientists prepare review articles or book chapters that summarize a body of knowledge on a given subject matter, meant to be more holistic recounts of a body of literature. Yet, by necessity, such summaries are often still narrow in their scope and are told from the perspective of a particular discipline. In other words, interdisciplinary reviews or book chapters tend to be the rarity rather than the norm. Here, we advocate for and highlight the benefits of interdisciplinary perspectives on microbiological subjects.
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Affiliation(s)
- Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Rachel L Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Manjinder Kour
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Daniel R Colman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
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15
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Abstract
Little is known of acetogens in contemporary serpentinizing systems, despite widely supported theories that serpentinite-hosted environments supported the first life on Earth via acetogenesis. To address this knowledge gap, genome-resolved metagenomics was applied to subsurface fracture water communities from an area of active serpentinization in the Samail Ophiolite, Sultanate of Oman. Two deeply branching putative bacterial acetogen types were identified in the communities belonging to the Acetothermia (hereafter, types I and II) that exhibited distinct distributions among waters with lower and higher water-rock reaction (i.e., serpentinization influence), respectively. Metabolic reconstructions revealed contrasting core metabolic pathways of type I and II Acetothermia, including in acetogenic pathway components (e.g., bacterial- vs. archaeal-like carbon monoxide dehydrogenases [CODH], respectively), hydrogen use to drive acetogenesis, and chemiosmotic potential generation via respiratory (type I) or canonical acetogen ferredoxin-based complexes (type II). Notably, type II Acetothermia metabolic pathways allow for use of serpentinization-derived substrates and implicate them as key primary producers in contemporary hyperalkaline serpentinite environments. Phylogenomic analyses indicate that 1) archaeal-like CODH of the type II genomes and those of other serpentinite-associated Bacteria derive from a deeply rooted horizontal transfer or origin among archaeal methanogens and 2) Acetothermia are among the earliest evolving bacterial lineages. The discovery of dominant and early-branching acetogens in subsurface waters of the largest near-surface serpentinite formation provides insight into the physiological traits that likely facilitated rock-supported life to flourish on a primitive Earth and possibly on other rocky planets undergoing serpentinization.
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16
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Mei N, Postec A, Bartoli M, Vandecasteele C, Wils L, Gil L, Monnin C, Pelletier B, Erauso G, Quéméneur M. Methanobacterium alkalithermotolerans sp. nov., a novel alkaliphilic and hydrogen-utilizing methanogen isolated from an alkaline geothermal spring (La Crouen, New Caledonia). Int J Syst Evol Microbiol 2022; 72. [PMID: 36260502 DOI: 10.1099/ijsem.0.005554] [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] [Indexed: 06/16/2023] Open
Abstract
An anaerobic, hydrogenotrophic methane-producing archaeon was isolated from an alkaline thermal spring (42 °C, pH 9.0) in New Caledonia. This methanogen, designated strain CANT, is alkaliphilic, thermotolerant, with Gram-positive staining non-motile cells. Strain CANT grows autotrophically using hydrogen exclusively as an energy source and carbon dioxide as the sole carbon source (without the requirement of yeast extract or other organic compounds). It grows at 20-45 °C (optimum, 45 °C) and pH 7.3-9.7 (optimum, pH 9.0). NaCl is not required for growth (optimum 0 %) but is tolerated up to 1.5 %. It resists novobiocin, streptomycin and vancomycin but is inhibited by ampicillin and penicillin, among other antibiotics. The genome consists of a circular chromosome (2.2 Mb) containing 2126 predicted protein-encoding genes with a G+C content of 36.4 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain CANT is a member of the genus Methanobacterium, most closely related to the alkaliphilic Methanobacterium alcaliphilum WeN4T with 98.5 % 16S rRNA gene sequence identity. The genomes of strain CANT and M. alcaliphilum DSM 3459, sequenced in this study, share 71.6 % average nucleotide identity and 14.0 % digital DNA-DNA hybridization. Therefore, phylogenetic and physiological results indicate that strain CANT represents a novel species, for which the name Methanobacterium alkalithermotolerans sp. nov. is proposed, and strain CANT (=DSM 102889T= JCM 31304T) is assigned as the type strain.
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Affiliation(s)
- Nan Mei
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
- Present address: School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China
| | - Anne Postec
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - Manon Bartoli
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | | | - Laura Wils
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - Lisa Gil
- INRAE, US 1426, GeT-PlaGe, Genotoul, Castanet-Tolosan, France
| | - Christophe Monnin
- GET UMR5563 (CNRS/UPS/IRD/CNES), Géosciences Environnement Toulouse, 14 Avenue Edouard Belin, 31400 Toulouse, France
| | - Bernard Pelletier
- UMR Géoazur, Centre IRD de Nouméa, 101 Promenade Roger Laroque, BP A5 - 98848 Nouméa cedex, New Caledonia
| | - Gael Erauso
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
| | - Marianne Quéméneur
- Aix Marseille Univ, Université de Toulon, CNRS, IRD, MIO, Marseille, France
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17
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Brazelton WJ, McGonigle JM, Motamedi S, Pendleton HL, Twing KI, Miller BC, Lowe WJ, Hoffman AM, Prator CA, Chadwick GL, Anderson RE, Thomas E, Butterfield DA, Aquino KA, Früh-Green GL, Schrenk MO, Lang SQ. Metabolic Strategies Shared by Basement Residents of the Lost City Hydrothermal Field. Appl Environ Microbiol 2022; 88:e0092922. [PMID: 35950875 PMCID: PMC9469722 DOI: 10.1128/aem.00929-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/28/2022] [Indexed: 12/14/2022] Open
Abstract
Alkaline fluids venting from chimneys of the Lost City hydrothermal field flow from a potentially vast microbial habitat within the seafloor where energy and organic molecules are released by chemical reactions within rocks uplifted from Earth's mantle. In this study, we investigated hydrothermal fluids venting from Lost City chimneys as windows into subseafloor environments where the products of geochemical reactions, such as molecular hydrogen (H2), formate, and methane, may be the only available sources of energy for biological activity. Our deep sequencing of metagenomes and metatranscriptomes from these hydrothermal fluids revealed a few key species of archaea and bacteria that are likely to play critical roles in the subseafloor microbial ecosystem. We identified a population of Thermodesulfovibrionales (belonging to phylum Nitrospirota) as a prevalent sulfate-reducing bacterium that may be responsible for much of the consumption of H2 and sulfate in Lost City fluids. Metagenome-assembled genomes (MAGs) classified as Methanosarcinaceae and Candidatus Bipolaricaulota were also recovered from venting fluids and represent potential methanogenic and acetogenic members of the subseafloor ecosystem. These genomes share novel hydrogenases and formate dehydrogenase-like sequences that may be unique to hydrothermal environments where H2 and formate are much more abundant than carbon dioxide. The results of this study include multiple examples of metabolic strategies that appear to be advantageous in hydrothermal and subsurface alkaline environments where energy and carbon are provided by geochemical reactions. IMPORTANCE The Lost City hydrothermal field is an iconic example of a microbial ecosystem fueled by energy and carbon from Earth's mantle. Uplift of mantle rocks into the seafloor can trigger a process known as serpentinization that releases molecular hydrogen (H2) and creates unusual environmental conditions where simple organic carbon molecules are more stable than dissolved inorganic carbon. This study provides an initial glimpse into the kinds of microbes that live deep within the seafloor where serpentinization takes place, by sampling hydrothermal fluids exiting from the Lost City chimneys. The metabolic strategies that these microbes appear to be using are also shared by microbes that inhabit other sites of serpentinization, including continental subsurface environments and natural springs. Therefore, the results of this study contribute to a broader, interdisciplinary effort to understand the general principles and mechanisms by which serpentinization-associated processes can support life on Earth and perhaps other worlds.
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Affiliation(s)
| | - Julia M. McGonigle
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, USA
| | - Shahrzad Motamedi
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | | | - Katrina I. Twing
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Briggs C. Miller
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - William J. Lowe
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | | | - Cecilia A. Prator
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Grayson L. Chadwick
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Rika E. Anderson
- Department of Biology, Carleton College, Northfield, Minnesota, USA
| | - Elaina Thomas
- Department of Biology, Carleton College, Northfield, Minnesota, USA
| | - David A. Butterfield
- Joint Institute for the Study of Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
| | | | | | - Matthew O. Schrenk
- Department of Earth and Environmental Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Susan Q. Lang
- School of the Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina, USA
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18
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Trutschel LR, Chadwick GL, Kruger B, Blank JG, Brazelton WJ, Dart ER, Rowe AR. Investigation of microbial metabolisms in an extremely high pH marine-like terrestrial serpentinizing system: Ney Springs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 836:155492. [PMID: 35476949 DOI: 10.1016/j.scitotenv.2022.155492] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/06/2022] [Accepted: 04/20/2022] [Indexed: 06/14/2023]
Abstract
Ney Springs, a continental serpentinizing spring in northern California, has an exceptionally high reported pH (12.4) for a naturally occurring water source. With high conductivity fluids, it is geochemically more akin to marine serpentinizing systems than other terrestrial locations. Our geochemical analyses also revealed high sulfide concentrations (544 mg/L) and methane emissions (83% volume gas content) relative to other serpentinizing systems. Thermodynamic calculations were used to investigate the potential for substrates resulting from serpentinization to fuel microbial life, and were found to support the energetic feasibility of sulfate reduction, anaerobic methane oxidation, denitrification, and anaerobic sulfide oxidation within this system. Assessment of the microbial community via 16S rRNA taxonomic gene surveys and metagenome sequencing revealed a community composition dominated by poorly characterized members of the Izemoplasmatales and Clostridiales. The genomes of these dominant taxa point to a fermentative lifestyle, though other highly complete (>90%) metagenome assembled genomes support the potential for organisms to perform sulfate reduction, sulfur disproportionation and/or sulfur oxidation (aerobic and anaerobic). Two chemolithoheterotrophs identified in the metagenome, a Halomonas sp. and a Rhodobacteraceae sp., were isolated and shown to oxidize thiosulfate and were capable of growth in conditions up to pH 12.4. Despite being characteristic products of serpentinization reactions, little evidence was seen for hydrogen and methane utilization in the Ney Springs microbial community. Hydrogen is not highly abundant and could be consumed prior to reaching the spring community. Other metabolic strategies may be outcompeted by more energetically favorable heterotrophic or fermentation reactions, or even inhibited by other compounds in the spring such as ammonia. The unique geochemistry of Ney Springs provides an opportunity to study how local geology interacts with serpentinized fluids, while its microbial community can better inform us of the metabolic strategies employed in hyperalkaline environments.
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Affiliation(s)
- Leah R Trutschel
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA
| | - Grayson L Chadwick
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | | | - Jennifer G Blank
- Blue Marble Space Institute of Science, Livermore, CA, USA; NASA Ames Research Center in Silicon Valley, Moffett Field, CA, USA
| | | | - Emily R Dart
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Annette R Rowe
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA.
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19
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Meyer-Dombard DR, Malas J. Advances in Defining Ecosystem Functions of the Terrestrial Subsurface Biosphere. Front Microbiol 2022; 13:891528. [PMID: 35722320 PMCID: PMC9201636 DOI: 10.3389/fmicb.2022.891528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
The subsurface is one of the last remaining 'uncharted territories' of Earth and is now accepted as a biosphere in its own right, at least as critical to Earth systems as the surface biosphere. The terrestrial deep biosphere is connected through a thin veneer of Earth's crust to the surface biosphere, and many subsurface biosphere ecosystems are impacted by surface topography, climate, and near surface groundwater movement and represent a transition zone (at least ephemerally). Delving below this transition zone, we can examine how microbial metabolic functions define a deep terrestrial subsurface. This review provides a survey of the most recent advances in discovering the functional and genomic diversity of the terrestrial subsurface biosphere, how microbes interact with minerals and obtain energy and carbon in the subsurface, and considers adaptations to the presented environmental extremes. We highlight the deepest subsurface studies in deep mines, deep laboratories, and boreholes in crystalline and altered host rock lithologies, with a focus on advances in understanding ecosystem functions in a holistic manner.
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20
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Fones EM, Templeton AS, Mogk DW, Boyd ES. Transformation of low molecular weight organic acids by microbial endoliths in subsurface mafic and ultramafic igneous rock. Environ Microbiol 2022; 24:4137-4152. [PMID: 35590457 DOI: 10.1111/1462-2920.16041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/13/2022] [Accepted: 05/05/2022] [Indexed: 11/28/2022]
Abstract
A growing body of work indicates that continental subsurface rocks host a substantial portion of the Earth's biosphere. However, the activities of microbial cells inhabiting pore spaces and microfractures in subsurface rocks remain underexplored. Here, we develop and optimize microcosm assays to detect organic acid transformation activities of cells residing in mafic to ultramafic igneous rocks. Application of this assay to gabbro core from the Stillwater Mine, Montana, USA, revealed maximal methane production from acetate at temperatures approximating that of the mine. Controls show that these activities are not due to contamination introduced during drilling, exhumation, or laboratory processing of the core. The assay was then applied to rocks cored from the Samail Ophiolite, Oman, which is undergoing low temperature serpentinization. Production of i) carbon dioxide from acetate and formate and ii) methane from formate were detected in a dunite/harzburgite rock core interfacing pH 9.6 waters, and estimates of microbial activities were up to three orders of magnitude higher in the rock core pore space than in corresponding waters. The detection of endolithic microbial activities in igneous rocks has implications for life detection on other planetary bodies where similar rock types prevail, such as Mars, Europa, and Enceladus. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Elizabeth M Fones
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, 59717
| | - Alexis S Templeton
- Department of Geological Sciences, University of Colorado, Boulder, CO, 80309
| | - David W Mogk
- Department of Earth Sciences, Montana State University, Bozeman, MT, 59717
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, 59717
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21
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Wang Y, Li W, Baker BJ, Zhou Y, He L, Danchin A, Li Q, Gao Z. Carbon metabolism and adaptation of hyperalkaliphilic microbes in serpentinizing spring of Manleluag, the Philippines. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:308-319. [PMID: 35199456 DOI: 10.1111/1758-2229.13052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Reduced substrates produced by the serpentinization reaction under hydration of olivine may have fuelled biological processes on early Earth. To understand the adaptive strategies and carbon metabolism of the microbes in the serpentinizing ecosystems, we reconstructed 18 draft genomes representing dominant species of Omnitrophicaeota, Gammaproteobacteria and Methanobacteria from the Manleluag serpentinizing spring in Zambales, Philippines (hyperalkaline and rich in methane and hydrogen). Phylogenomics revealed that two genomes were affiliated with a candidate phylum NPL-UPA2 and the references of all our genomes were derived from ground waters, hot springs and the deep biosphere. C1 metabolism appears to be widespread as most of the genomes code for methanogenesis, CO oxidation and CO2 fixation. However, likely due to the low CO2 concentration and election acceptors, the biomass in the spring was extremely low (<103 cell/ml). Various Na+ and K+ transporters and Na+ -driving ATPases appear to be encoded by these genomes, suggesting that nutrient acquisition, bioenergetics and normal cytoplasmic pH were dependent on Na+ and K+ pumps. Our results advance our understanding of the metabolic potentials and bioenergetics of serpentinizing springs and provide a framework of the ecology of early Earth.
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Affiliation(s)
- Yong Wang
- Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, P. R. China
| | - Wenli Li
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, P. R. China
| | - Brett J Baker
- Department of Integrative Biology and Marine Science, University of Texas Austin, Austin, TX, 78373, USA
| | - Yingli Zhou
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Lisheng He
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, P. R. China
| | - Antoine Danchin
- Kodikos Labs, Institut Cochin, 24 rue du Faubourg Saint Jacques, Paris, 75014, France
| | - Qingmei Li
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhaoming Gao
- Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, P. R. China
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22
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Liu L, Xiong R, Li Y, Chen L, Han R. Anaerobic digestion characteristics and key microorganisms associated with low-temperature rapeseed cake and sheep manure fermentation. Arch Microbiol 2022; 204:188. [PMID: 35192067 DOI: 10.1007/s00203-022-02796-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 01/16/2022] [Accepted: 02/07/2022] [Indexed: 01/03/2023]
Abstract
In this study, gas production from mixed anaerobic fermentation of rapeseed cake and sheep manure at low temperature (15.2-17.8 °C) was investigated in Qinghai rural household biogas digesters to understand the temporal dynamics of key microbial populations involved in fermentations. Different raw material ratios resulted in significantly different effects on biogas yields and microbial community compositions over 40 days. When the dry weight ratio of sheep manure to rapeseed cake was 1:2, the highest level of cumulative gas production was observed (122.92 m3·t-1). Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant bacterial phyla among the 29 digester samples (total relative abundances > 79.23%), followed by Synergistetes (4.09-10.7%). Lactobacillus was the most abundant genus in the biogas digesters with high rapeseed cake contents (average relative abundances: 14.68%), while Peptoniphilus exhibited higher abundances (12.69%) in the mixed treatments. In addition, unclassified Synergistaceae abundances (6.64%) were positively associated with biogas production variation among treatments. Bacteroides (5.74%) and Pseudomonas (5.24%) both accounted for larger proportions of communities in the digesters that used more sheep manure. Methanomicrobiales (66.55%) was the most dominant archaeal group among digesters, with Methanogenium (41.82%) and Methanoculleus (16.55%) representing the main gas-producing archaeal genera; they were more abundant in biogas digesters with higher sheep manure contents and higher rapeseed cake contents, respectively. VFAs and pH were the main factors associated with differences in microbial communities among the 29 samples. Specifically, VFA concentrations were positively correlated with Lactobacillus, Methanoculleus and Methanothrix abundances, while pH was positively correlated with Bacteroides, Pseudomonas, and Methanobacterium abundances.
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Affiliation(s)
- Li Liu
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry Sciences, Qinghai University, Ningda Road 253, Xining, 810016, Qinghai, China
| | - Rongbo Xiong
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry Sciences, Qinghai University, Ningda Road 253, Xining, 810016, Qinghai, China
| | - Yi Li
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry Sciences, Qinghai University, Ningda Road 253, Xining, 810016, Qinghai, China
| | - Laisheng Chen
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry Sciences, Qinghai University, Ningda Road 253, Xining, 810016, Qinghai, China
| | - Rui Han
- Qinghai Key Laboratory of Vegetable Genetics and Physiology, Academy of Agriculture and Forestry Sciences, Qinghai University, Ningda Road 253, Xining, 810016, Qinghai, China.
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23
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Coskun ÖK, Vuillemin A, Schubotz F, Klein F, Sichel SE, Eisenreich W, Orsi WD. Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. ISME JOURNAL 2021; 16:257-271. [PMID: 34312482 PMCID: PMC8692406 DOI: 10.1038/s41396-021-01066-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022]
Abstract
Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.
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Affiliation(s)
- Ömer K Coskun
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany
| | - Aurèle Vuillemin
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany.,GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Florence Schubotz
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Frieder Klein
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Susanna E Sichel
- Departamento de Geologia e Geofísica/LAGEMAR-Universidade Federal Fluminense-Brazil, Niterói, RJ, Brazil
| | - Wolfgang Eisenreich
- Department of Chemistry, Bavarian NMR Center-Structural Membrane Biochemistry, Technische Universität München, Garching, Germany
| | - William D Orsi
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany. .,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany.
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24
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Procaryotic Diversity and Hydrogenotrophic Methanogenesis in an Alkaline Spring (La Crouen, New Caledonia). Microorganisms 2021; 9:microorganisms9071360. [PMID: 34201651 PMCID: PMC8307142 DOI: 10.3390/microorganisms9071360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/17/2021] [Accepted: 06/19/2021] [Indexed: 01/01/2023] Open
Abstract
(1) Background: The geothermal spring of La Crouen (New Caledonia) discharges warm (42 °C) alkaline water (pH~9) enriched in dissolved nitrogen with traces of methane, but its microbial diversity has not yet been studied. (2) Methods: Cultivation-dependent and -independent methods (e.g., Illumina sequencing and quantitative PCR based on 16S rRNA gene) were used to describe the prokaryotic diversity of this spring. (3) Results: Prokaryotes were mainly represented by Proteobacteria (57% on average), followed by Cyanobacteria, Chlorofexi, and Candidatus Gracilibacteria (GN02/BD1-5) (each > 5%). Both potential aerobes and anaerobes, as well as mesophilic and thermophilic microorganisms, were identified. Some of them had previously been detected in continental hyperalkaline springs found in serpentinizing environments (The Cedars, Samail, Voltri, and Zambales ophiolites). Gammaproteobacteria, Ca. Gracilibacteria and Thermotogae were significantly more abundant in spring water than in sediments. Potential chemolithotrophs mainly included beta- and gammaproteobacterial genera of sulfate-reducers (Ca. Desulfobacillus), methylotrophs (Methyloversatilis), sulfur-oxidizers (Thiofaba, Thiovirga), or hydrogen-oxidizers (Hydrogenophaga). Methanogens (Methanobacteriales and Methanosarcinales) were the dominant Archaea, as found in serpentinization-driven and deep subsurface ecosystems. A novel alkaliphilic hydrogenotrophic methanogen (strain CAN) belonging to the genus Methanobacterium was isolated, suggesting that hydrogenotrophic methanogenesis occurs at La Crouen.
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25
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Ando N, Barquera B, Bartlett DH, Boyd E, Burnim AA, Byer AS, Colman D, Gillilan RE, Gruebele M, Makhatadze G, Royer CA, Shock E, Wand AJ, Watkins MB. The Molecular Basis for Life in Extreme Environments. Annu Rev Biophys 2021; 50:343-372. [PMID: 33637008 DOI: 10.1146/annurev-biophys-100120-072804] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sampling and genomic efforts over the past decade have revealed an enormous quantity and diversity of life in Earth's extreme environments. This new knowledge of life on Earth poses the challenge of understandingits molecular basis in such inhospitable conditions, given that such conditions lead to loss of structure and of function in biomolecules from mesophiles. In this review, we discuss the physicochemical properties of extreme environments. We present the state of recent progress in extreme environmental genomics. We then present an overview of our current understanding of the biomolecular adaptation to extreme conditions. As our current and future understanding of biomolecular structure-function relationships in extremophiles requires methodologies adapted to extremes of pressure, temperature, and chemical composition, advances in instrumentation for probing biophysical properties under extreme conditions are presented. Finally, we briefly discuss possible future directions in extreme biophysics.
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Affiliation(s)
- Nozomi Ando
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA.,Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Blanca Barquera
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, USA;
| | - Douglas H Bartlett
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0202, USA
| | - Eric Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59717, USA
| | - Audrey A Burnim
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Amanda S Byer
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Daniel Colman
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59717, USA
| | - Richard E Gillilan
- Center for High Energy X-ray Sciences (CHEXS), Ithaca, New York 14853, USA
| | - Martin Gruebele
- Department of Chemistry, University of Illinois, Urbana-Champaign, Illinois 61801, USA.,Department of Physics, University of Illinois, Urbana-Champaign, Illinois 61801, USA.,Center for Biophysics and Quantitative Biology, University of Illinois, Urbana-Champaign, Illinois 61801, USA
| | - George Makhatadze
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, USA;
| | - Catherine A Royer
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, USA;
| | - Everett Shock
- GEOPIG, School of Earth & Space Exploration, School of Molecular Sciences, Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, Arizona 85287, USA
| | - A Joshua Wand
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77845, USA.,Department of Chemistry, Texas A&M University, College Station, Texas 77845, USA.,Department of Molecular & Cellular Medicine, Texas A&M University, College Station, Texas 77845, USA
| | - Maxwell B Watkins
- Department of Chemistry & Chemical Biology, Cornell University, Ithaca, New York 14853, USA.,Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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