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Fernandes-Martins MC, Colman DR, Boyd ES. Sulfide oxidation by members of the Sulfolobales. PNAS NEXUS 2024; 3:pgae201. [PMID: 38827816 PMCID: PMC11143483 DOI: 10.1093/pnasnexus/pgae201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/03/2024] [Indexed: 06/05/2024]
Abstract
The oxidation of sulfur compounds drives the acidification of geothermal waters. At high temperatures (>80°C) and in acidic conditions (pH <6.0), oxidation of sulfide has historically been considered an abiotic process that generates elemental sulfur (S0) that, in turn, is oxidized by thermoacidophiles of the model archaeal order Sulfolobales to generate sulfuric acid (i.e. sulfate and protons). Here, we describe five new aerobic and autotrophic strains of Sulfolobales comprising two species that were isolated from acidic hot springs in Yellowstone National Park (YNP) and that can use sulfide as an electron donor. These strains significantly accelerated the rate and extent of sulfide oxidation to sulfate relative to abiotic controls, concomitant with production of cells. Yields of sulfide-grown cultures were ∼2-fold greater than those of S0-grown cultures, consistent with thermodynamic calculations indicating more available energy in the former condition than the latter. Homologs of sulfide:quinone oxidoreductase (Sqr) were identified in nearly all Sulfolobales genomes from YNP metagenomes as well as those from other reference Sulfolobales, suggesting a widespread ability to accelerate sulfide oxidation. These observations expand the role of Sulfolobales in the oxidative sulfur cycle, the geobiological feedbacks that drive the formation of acidic hot springs, and landscape evolution.
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Affiliation(s)
| | - Daniel R Colman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
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Rhim JH, Zhou A, Amenabar MJ, Boyer GM, Elling FJ, Weber Y, Pearson A, Boyd ES, Leavitt WD. Mode of carbon and energy metabolism shifts lipid composition in the thermoacidophile Acidianus. Appl Environ Microbiol 2024; 90:e0136923. [PMID: 38236067 PMCID: PMC10880624 DOI: 10.1128/aem.01369-23] [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: 08/09/2023] [Accepted: 12/01/2023] [Indexed: 01/19/2024] Open
Abstract
The degree of cyclization, or ring index (RI), in archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids was long thought to reflect homeoviscous adaptation to temperature. However, more recent experiments show that other factors (e.g., pH, growth phase, and energy flux) can also affect membrane composition. The main objective of this study was to investigate the effect of carbon and energy metabolism on membrane cyclization. To do so, we cultivated Acidianus sp. DS80, a metabolically flexible and thermoacidophilic archaeon, on different electron donor, acceptor, and carbon source combinations (S0/Fe3+/CO2, H2/Fe3+/CO2, H2/S0/CO2, or H2/S0/glucose). We show that differences in energy and carbon metabolism can result in over a full unit of change in RI in the thermoacidophile Acidianus sp. DS80. The patterns in RI correlated with the normalized electron transfer rate between the electron donor and acceptor and did not always align with thermodynamic predictions of energy yield. In light of this, we discuss other factors that may affect the kinetics of cellular energy metabolism: electron transfer chain (ETC) efficiency, location of ETC reaction components (cytoplasmic vs. extracellular), and the physical state of electron donors and acceptors (gas vs. solid). Furthermore, the assimilation of a more reduced form of carbon during heterotrophy appears to decrease the demand for reducing equivalents during lipid biosynthesis, resulting in lower RI. Together, these results point to the fundamental role of the cellular energy state in dictating GDGT cyclization, with those cells experiencing greater energy limitation synthesizing more cyclized GDGTs.IMPORTANCESome archaea make unique membrane-spanning lipids with different numbers of five- or six-membered rings in the core structure, which modulate membrane fluidity and permeability. Changes in membrane core lipid composition reflect the fundamental adaptation strategies of archaea in response to stress, but multiple environmental and physiological factors may affect the needs for membrane fluidity and permeability. In this study, we tested how Acidianus sp. DS80 changed its core lipid composition when grown with different electron donor/acceptor pairs. We show that changes in energy and carbon metabolisms significantly affected the relative abundance of rings in the core lipids of DS80. These observations highlight the need to better constrain metabolic parameters, in addition to environmental factors, which may influence changes in membrane physiology in Archaea. Such consideration would be particularly important for studying archaeal lipids from habitats that experience frequent environmental fluctuations and/or where metabolically diverse archaea thrive.
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Affiliation(s)
- Jeemin H. Rhim
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, California, USA
| | - Alice Zhou
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Maximiliano J. Amenabar
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Grayson M. Boyer
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, USA
| | - Felix J. Elling
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA
- Leibniz-Laboratory for Radiometric Dating and Isotope Research, Christian-Albrecht University of Kiel, Kiel, Germany
| | - Yuki Weber
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Ann Pearson
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Eric S. Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - William D. Leavitt
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
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Tian J, Deng W, Zhang Z, Xu J, Yang G, Zhao G, Yang S, Jiang W, Gu Y. Discovery and remodeling of Vibrio natriegens as a microbial platform for efficient formic acid biorefinery. Nat Commun 2023; 14:7758. [PMID: 38012202 PMCID: PMC10682008 DOI: 10.1038/s41467-023-43631-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023] Open
Abstract
Formic acid (FA) has emerged as a promising one-carbon feedstock for biorefinery. However, developing efficient microbial hosts for economically competitive FA utilization remains a grand challenge. Here, we discover that the bacterium Vibrio natriegens has exceptional FA tolerance and metabolic capacity natively. This bacterium is remodeled by rewiring the serine cycle and the TCA cycle, resulting in a non-native closed loop (S-TCA) which as a powerful metabolic sink, in combination with laboratory evolution, enables rapid emergence of synthetic strains with significantly improved FA-utilizing ability. Further introduction of a foreign indigoidine-forming pathway into the synthetic V. natriegens strain leads to the production of 29.0 g · L-1 indigoidine and consumption of 165.3 g · L-1 formate within 72 h, achieving a formate consumption rate of 2.3 g · L-1 · h-1. This work provides an important microbial chassis as well as design rules to develop industrially viable microorganisms for FA biorefinery.
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Affiliation(s)
- Jinzhong Tian
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
- Xianghu Laboratory, Hangzhou, 311231, China.
| | - Wangshuying Deng
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ziwen Zhang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jiaqi Xu
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, 311215, China
| | | | - Guoping Zhao
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sheng Yang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Weihong Jiang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Yang Gu
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
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Lithogenic hydrogen supports microbial primary production in subglacial and proglacial environments. Proc Natl Acad Sci U S A 2020; 118:2007051117. [PMID: 33419920 PMCID: PMC7812807 DOI: 10.1073/pnas.2007051117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Life in environments devoid of photosynthesis, such as on early Earth or in contemporary dark subsurface ecosystems, is supported by chemical energy. How, when, and where chemical nutrients released from the geosphere fuel chemosynthetic biospheres is fundamental to understanding the distribution and diversity of life, both today and in the geologic past. Hydrogen (H2) is a potent reductant that can be generated when water interacts with reactive components of mineral surfaces such as silicate radicals and ferrous iron. Such reactive mineral surfaces are continually generated by physical comminution of bedrock by glaciers. Here, we show that dissolved H2 concentrations in meltwaters from an iron and silicate mineral-rich basaltic glacial catchment were an order of magnitude higher than those from a carbonate-dominated catchment. Consistent with higher H2 abundance, sediment microbial communities from the basaltic catchment exhibited significantly shorter lag times and faster rates of net H2 oxidation and dark carbon dioxide (CO2) fixation than those from the carbonate catchment, indicating adaptation to use H2 as a reductant in basaltic catchments. An enrichment culture of basaltic sediments provided with H2, CO2, and ferric iron produced a chemolithoautotrophic population related to Rhodoferax ferrireducens with a metabolism previously thought to be restricted to (hyper)thermophiles and acidophiles. These findings point to the importance of physical and chemical weathering processes in generating nutrients that support chemosynthetic primary production. Furthermore, they show that differences in bedrock mineral composition can influence the supplies of nutrients like H2 and, in turn, the diversity, abundance, and activity of microbial inhabitants.
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Nancucheo I, Johnson DB. Characteristics of an Iron-Reducing, Moderately Acidophilic Actinobacterium Isolated from Pyritic Mine Waste, and Its Potential Role in Mitigating Mineral Dissolution in Mineral Tailings Deposits. Microorganisms 2020; 8:E990. [PMID: 32630740 PMCID: PMC7409166 DOI: 10.3390/microorganisms8070990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 11/16/2022] Open
Abstract
Reactive pyritic mine tailings can be populated by chemolithotrophic prokaryotes that enhance the solubilities of many metals, though iron-reducing heterotrophic microorganisms can inhibit the environmental risk posed by tailings by promoting processes that are the reverse of those carried out by pyrite-oxidising autotrophic bacteria. A strain (IT2) of Curtobacterium ammoniigenes, a bacterium not previously identified as being associated with acidic mine wastes, was isolated from pyritic mine tailings and partially characterized. Strain IT2 was able to reduce ferric iron under anaerobic conditions, but was not found to catalyse the oxidation of ferrous iron or elemental (zero-valent) sulfur, and was an obligate heterotrophic. It metabolized monosaccharides and required small amounts of yeast extract for growth. Isolate IT2 is a mesophilic bacterium, with a temperature growth optimum of 30 °C and is moderately acidophilic, growing optimally at pH 4.0 and between pH 2.7 and 5.0. The isolate tolerated elevated concentrations of many transition metals, and was able to grow in the cell-free spent medium of the acidophilic autotroph Acidithiobacillus ferrooxidans, supporting the hypothesis that it can proliferate in acidic mine tailings. Its potential role in mitigating the production of acidic, metal-rich drainage waters from mine wastes is discussed.
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Affiliation(s)
- Ivan Nancucheo
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Lientur 1457, Concepción 4080871, Chile
| | - D. Barrie Johnson
- School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 4UF, UK;
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Discovery and Characterization of Thermoproteus Spherical Piliferous Virus 1: a Spherical Archaeal Virus Decorated with Unusual Filaments. J Virol 2020; 94:JVI.00036-20. [PMID: 32213609 DOI: 10.1128/jvi.00036-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/08/2020] [Indexed: 11/20/2022] Open
Abstract
We describe the discovery of an archaeal virus, one that infects archaea, tentatively named Thermoproteus spherical piliferous virus 1 (TSPV1), which was purified from a Thermoproteales host isolated from a hot spring in Yellowstone National Park (USA). TSPV1 packages an 18.65-kb linear double-stranded DNA (dsDNA) genome with 31 open reading frames (ORFs), whose predicted gene products show little homology to proteins with known functions. A comparison of virus particle morphologies and gene content demonstrates that TSPV1 is a new member of the Globuloviridae family of archaeal viruses. However, unlike other Globuloviridae members, TSPV1 has numerous highly unusual filaments decorating its surface, which can extend hundreds of nanometers from the virion. To our knowledge, similar filaments have not been observed in any other archaeal virus. The filaments are remarkably stable, remaining intact across a broad range of temperature and pH values, and they are resistant to chemical denaturation and proteolysis. A major component of the filaments is a glycosylated 35-kDa TSPV1 protein (TSPV1 GP24). The filament protein lacks detectable homology to structurally or functionally characterized proteins. We propose, given the low host cell densities of hot spring environments, that the TSPV1 filaments serve to increase the probability of virus attachment and entry into host cells.IMPORTANCE High-temperature environments have proven to be an important source for the discovery of new archaeal viruses with unusual particle morphologies and gene content. Our isolation of Thermoproteus spherical piliferous virus 1 (TSPV1), with numerous filaments extending from the virion surface, expands our understanding of viral diversity and provides new insight into viral replication in high-temperature environments.
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A review of the mechanisms of mineral-based metabolism in early Earth analog rock-hosted hydrothermal ecosystems. World J Microbiol Biotechnol 2019; 35:29. [PMID: 30689069 DOI: 10.1007/s11274-019-2604-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 01/20/2019] [Indexed: 10/27/2022]
Abstract
Prior to the advent of oxygenic photosynthesis ~ 2.8-3.2 Ga, life was dependent on chemical energy captured from oxidation-reduction reactions involving minerals or substrates generated through interaction of water with minerals. Terrestrial hydrothermal environments host abundant and diverse non-photosynthetic communities and a variety of minerals that can sustain microbial metabolism. Minerals and substrates generated through interaction of minerals with water are differentially distributed in hot spring environments which, in turn, shapes the distribution of microbial life and the metabolic processes that support it. Emerging evidence suggests that terrestrial hydrothermal environments may have played a role in supporting the metabolism of the earliest forms of microbial life. It follows that these environments and their microbial inhabitants are increasingly being studied as analogs of early Earth ecosystems. Here we review current understanding of the processes that lead to variation in the availability of minerals or mineral-sourced substrates in terrestrial hydrothermal environments. In addition, we summarize proposed mechanisms of mineral substrate acquisition and metabolism in microbial cells inhabiting terrestrial hydrothermal environments, highlighting the importance of the dynamic interplay between biotic and abiotic reactions in influencing mineral substrate bioavailability. An emphasis is placed on mechanisms involved in the solubilization, acquisition, and metabolism of sulfur- and iron-bearing minerals, since these elements were likely integrated into the metabolism of the earliest anaerobic cells.
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Amenabar MJ, Colman DR, Poudel S, Roden EE, Boyd ES. Electron acceptor availability alters carbon and energy metabolism in a thermoacidophile. Environ Microbiol 2018; 20:2523-2537. [PMID: 29749696 DOI: 10.1111/1462-2920.14270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 04/27/2018] [Accepted: 05/04/2018] [Indexed: 12/17/2022]
Abstract
The thermoacidophilic Acidianus strain DS80 displays versatility in its energy metabolism and can grow autotrophically and heterotrophically with elemental sulfur (S°), ferric iron (Fe3+ ) or oxygen (O2 ) as electron acceptors. Here, we show that autotrophic and heterotrophic growth with S° as the electron acceptor is obligately dependent on hydrogen (H2 ) as electron donor; organic substrates such as acetate can only serve as a carbon source. In contrast, organic substrates such as acetate can serve as electron donor and carbon source for Fe3+ or O2 grown cells. During growth on S° or Fe3+ with H2 as an electron donor, the amount of CO2 assimilated into biomass decreased when cultures were provided with acetate. The addition of CO2 to cultures decreased the amount of acetate mineralized and assimilated and increased cell production in H2 /Fe3+ grown cells but had no effect on H2 /S° grown cells. In acetate/Fe3+ grown cells, the presence of H2 decreased the amount of acetate mineralized as CO2 in cultures compared to those without H2 . These results indicate that electron acceptor availability constrains the variety of carbon sources used by this strain. Addition of H2 to cultures overcomes this limitation and alters heterotrophic metabolism.
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Affiliation(s)
| | - Daniel R Colman
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Saroj Poudel
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Eric E Roden
- Department of Geosciences, University of Wisconsin, Madison, WI, USA.,NASA Astrobiology Institute, Mountain View, CA, USA
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA.,NASA Astrobiology Institute, Mountain View, CA, USA
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Amenabar MJ, Shock EL, Roden EE, Peters JW, Boyd ES. Microbial substrate preference dictated by energy demand, not supply. NATURE GEOSCIENCE 2017; 10:577-581. [PMID: 30944580 PMCID: PMC6443248 DOI: 10.1038/ngeo2978] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 06/02/2017] [Indexed: 06/08/2023]
Abstract
Growth substrates that maximize energy yield are widely thought to be utilized preferentially by microorganisms. However, observed distributions of microorganisms and their activities often deviate from predictions based solely on thermodynamic considerations of substrate energy supply. Here we present observations of the bioenergetics and growth yields of a metabolically flexible, thermophilic strain of the archaeon Acidianus when grown autotrophically on minimal medium with hydrogen (H2) or elemental sulfur (S°) as an electron donor, and S° or ferric iron (Fe3+) as an electron acceptor. Thermodynamic calculations indicate that S°/Fe3+ and H2/Fe3+ yield three- and four-fold more energy per mol electron transferred, respectively, than the H2/S° couple. However, biomass yields in Acidianus cultures provided with H2/S° were eight-fold greater than when provided S°/Fe3+ or H2/Fe3+, indicating the H2/S° redox couple is preferred. Indeed, cells provided with all three growth substrates (H2, Fe3+, and S°) grew preferentially by reduction of S° with H2. We conclude that substrate preference is dictated by differences in the energy demand of electron transfer reactions in Acidianus when grown with different substrates, rather than substrate energy supply.
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Affiliation(s)
| | - Everett L. Shock
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, Arizona
- NASA Astrobiology Institute, Mountain View, California
| | - Eric E. Roden
- Department of Geosciences, University of Wisconsin, Madison, Wisconsin
- NASA Astrobiology Institute, Mountain View, California
| | - John W. Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana
| | - Eric S. Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana
- NASA Astrobiology Institute, Mountain View, California
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