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Schmitz RA, Peeters SH, Versantvoort W, Picone N, Pol A, Jetten MSM, Op den Camp HJM. Verrucomicrobial methanotrophs: ecophysiology of metabolically versatile acidophiles. FEMS Microbiol Rev 2021; 45:6125968. [PMID: 33524112 PMCID: PMC8498564 DOI: 10.1093/femsre/fuab007] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Methanotrophs are an important group of microorganisms that counteract methane emissions to the atmosphere. Methane-oxidising bacteria of the Alpha- and Gammaproteobacteria have been studied for over a century, while methanotrophs of the phylum Verrucomicrobia are a more recent discovery. Verrucomicrobial methanotrophs are extremophiles that live in very acidic geothermal ecosystems. Currently, more than a dozen strains have been isolated, belonging to the genera Methylacidiphilum and Methylacidimicrobium. Initially, these methanotrophs were thought to be metabolically confined. However, genomic analyses and physiological and biochemical experiments over the past years revealed that verrucomicrobial methanotrophs, as well as proteobacterial methanotrophs, are much more metabolically versatile than previously assumed. Several inorganic gases and other molecules present in acidic geothermal ecosystems can be utilised, such as methane, hydrogen gas, carbon dioxide, ammonium, nitrogen gas and perhaps also hydrogen sulfide. Verrucomicrobial methanotrophs could therefore represent key players in multiple volcanic nutrient cycles and in the mitigation of greenhouse gas emissions from geothermal ecosystems. Here, we summarise the current knowledge on verrucomicrobial methanotrophs with respect to their metabolic versatility and discuss the factors that determine their diversity in their natural environment. In addition, key metabolic, morphological and ecological characteristics of verrucomicrobial and proteobacterial methanotrophs are reviewed.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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Poghosyan L, Koch H, Lavy A, Frank J, van Kessel MA, Jetten MS, Banfield JF, Lücker S. Metagenomic recovery of two distinct comammox Nitrospira from the terrestrial subsurface. Environ Microbiol 2019; 21:3627-3637. [PMID: 31107587 PMCID: PMC6852473 DOI: 10.1111/1462-2920.14691] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 12/19/2022]
Abstract
The recently discovered comammox process encompasses both nitrification steps, the aerobic oxidation of ammonia and nitrite, in a single organism. All known comammox bacteria are affiliated with Nitrospira sublineage II and can be grouped into two distinct clades, referred to as A and B, based on ammonia monooxygenase phylogeny. In this study, we report high-quality draft genomes of two novel comammox Nitrospira from the terrestrial subsurface, representing one clade A and one clade B comammox organism. The two metagenome-assembled genomes were compared with other representatives of Nitrospira sublineage II, including both canonical and comammox Nitrospira. Phylogenomic analyses confirmed the affiliation of the two novel Nitrospira with comammox clades A and B respectively. Based on phylogenetic distance and pairwise average nucleotide identity values, both comammox Nitrospira were classified as novel species. Genomic comparison revealed high conservation of key metabolic features in sublineage II Nitrospira, including respiratory complexes I-V and the machineries for nitrite oxidation and carbon fixation via the reductive tricarboxylic acid cycle. In addition, the presence of the enzymatic repertoire for formate and hydrogen oxidation in the Rifle clades A and B comammox genomes, respectively, suggest a broader distribution of these metabolic features than previously anticipated.
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Affiliation(s)
- Lianna Poghosyan
- Department of MicrobiologyRadboud UniversityHeyendaalseweg 135, 6525 AJNijmegenthe Netherlands
| | - Hanna Koch
- Department of MicrobiologyRadboud UniversityHeyendaalseweg 135, 6525 AJNijmegenthe Netherlands
| | - Adi Lavy
- Earth and Planetary Sciences DepartmentUniversity of California, 2151 Berkeley WayBerkleyCA94720USA
| | - Jeroen Frank
- Department of MicrobiologyRadboud UniversityHeyendaalseweg 135, 6525 AJNijmegenthe Netherlands
| | | | - Mike S.M. Jetten
- Department of MicrobiologyRadboud UniversityHeyendaalseweg 135, 6525 AJNijmegenthe Netherlands
| | - Jillian F. Banfield
- Earth and Planetary Sciences DepartmentUniversity of California, 2151 Berkeley WayBerkleyCA94720USA
| | - Sebastian Lücker
- Department of MicrobiologyRadboud UniversityHeyendaalseweg 135, 6525 AJNijmegenthe Netherlands
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Mixotrophy drives niche expansion of verrucomicrobial methanotrophs. ISME JOURNAL 2017; 11:2599-2610. [PMID: 28777381 PMCID: PMC5649168 DOI: 10.1038/ismej.2017.112] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/07/2017] [Accepted: 05/12/2017] [Indexed: 01/26/2023]
Abstract
Aerobic methanotrophic bacteria have evolved a specialist lifestyle dependent on consumption of methane and other short-chain carbon compounds. However, their apparent substrate specialism runs contrary to the high relative abundance of these microorganisms in dynamic environments, where the availability of methane and oxygen fluctuates. In this work, we provide in situ and ex situ evidence that verrucomicrobial methanotrophs are mixotrophs. Verrucomicrobia-dominated soil communities from an acidic geothermal field in Rotokawa, New Zealand rapidly oxidised methane and hydrogen simultaneously. We isolated and characterised a verrucomicrobial strain from these soils, Methylacidiphilum sp. RTK17.1, and showed that it constitutively oxidises molecular hydrogen. Genomic analysis confirmed that this strain encoded two [NiFe]-hydrogenases (group 1d and 3b), and biochemical assays revealed that it used hydrogen as an electron donor for aerobic respiration and carbon fixation. While the strain could grow heterotrophically on methane or autotrophically on hydrogen, it grew optimally by combining these metabolic strategies. Hydrogen oxidation was particularly important for adaptation to methane and oxygen limitation. Complementary to recent findings of hydrogenotrophic growth by Methylacidiphilum fumariolicum SolV, our findings illustrate that verrucomicrobial methanotrophs have evolved to simultaneously utilise hydrogen and methane from geothermal sources to meet energy and carbon demands where nutrient flux is dynamic. This mixotrophic lifestyle is likely to have facilitated expansion of the niche space occupied by these microorganisms, allowing them to become dominant in geothermally influenced surface soils. Genes encoding putative oxygen-tolerant uptake [NiFe]-hydrogenases were identified in all publicly available methanotroph genomes, suggesting hydrogen oxidation is a general metabolic strategy in this guild.
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Zeytun A, Sikorski J, Nolan M, Lapidus A, Lucas S, Han J, Tice H, Cheng JF, Tapia R, Goodwin L, Pitluck S, Liolios K, Ivanova N, Mavromatis K, Mikhailova N, Ovchinnikova G, Pati A, Chen A, Palaniappan K, Ngatchou-Djao OD, Land M, Hauser L, Jeffries CD, Han C, Detter JC, Ubler S, Rohde M, Tindall BJ, Göker M, Wirth R, Woyke T, Bristow J, Eisen JA, Markowitz V, Hugenholtz P, Klenk HP, Kyrpides NC. Complete genome sequence of Hydrogenobacter thermophilus type strain (TK-6). Stand Genomic Sci 2011; 4:131-43. [PMID: 21677850 PMCID: PMC3111988 DOI: 10.4056/sigs.1463589] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Hydrogenobacter thermophilus Kawasumi et al. 1984 is the type species of the genus Hydrogenobacter. H. thermophilus was the first obligate autotrophic organism reported among aerobic hydrogen-oxidizing bacteria. Strain TK-6(T) is of interest because of the unusually efficient hydrogen-oxidizing ability of this strain, which results in a faster generation time compared to other autotrophs. It is also able to grow anaerobically using nitrate as an electron acceptor when molecular hydrogen is used as the energy source, and able to aerobically fix CO(2)via the reductive tricarboxylic acid cycle. This is the fifth completed genome sequence in the family Aquificaceae, and the second genome sequence determined from a strain derived from the original isolate. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 1,742,932 bp long genome with its 1,899 protein-coding and 49 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
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Yamamoto M, Ikeda T, Arai H, Ishii M, Igarashi Y. Carboxylation reaction catalyzed by 2-oxoglutarate:ferredoxin oxidoreductases from Hydrogenobacter thermophilus. Extremophiles 2009; 14:79-85. [PMID: 19894084 DOI: 10.1007/s00792-009-0289-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 10/19/2009] [Indexed: 11/29/2022]
Abstract
Hydrogenobacter thermophilus TK-6 is a thermophilic, chemolithoautotrophic, hydrogen-oxidizing bacterium that fixes carbon dioxide via the reductive tricarboxylic acid (rTCA) cycle. 2-Oxoglutarate:ferredoxin oxidoreductase (OGOR) is the key enzyme in this cycle that fixes carbon dioxide. The genome of strain TK-6 encodes at least two distinct OGOR enzymes, termed For and Kor. We report here a method for measuring the carboxylation of succinyl-CoA catalyzed by OGORs. The method involves the in vitro coupling of OGOR with ferredoxin and pyruvate:ferredoxin oxidoreductase from strain TK-6, and glutamate dehydrogenase from Sulfolobus tokodaii. Using this method, we determined both the apparent maximum velocities and the K (m) values of For and Kor for the carboxylation of succinyl-CoA. This is the first reported kinetic analysis of carbon fixation catalyzed by OGOR enzymes from the rTCA cycle.
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Affiliation(s)
- Masahiro Yamamoto
- Department of Biotechnology, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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Yoon KS, Bobst C, Hemann CF, Hille R, Tabita FR. Spectroscopic and functional properties of novel 2[4Fe-4S] cluster-containing ferredoxins from the green sulfur bacterium Chlorobium tepidum. J Biol Chem 2001; 276:44027-36. [PMID: 11568186 DOI: 10.1074/jbc.m107852200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two distinct ferredoxins, Fd I and Fd II, were isolated and purified to homogeneity from photoautotrophically grown Chlorobium tepidum, a moderately thermophilic green sulfur bacterium that assimilates carbon dioxide by the reductive tricarboxylic acid cycle. Both ferredoxins serve a crucial role as electron donors for reductive carboxylation, catalyzed by a key enzyme of this pathway, pyruvate synthase/pyruvate ferredoxin oxidoreductase. The reduction potentials of Fd I and Fd II were determined by cyclic voltammetry to be -514 and -584 mV, respectively, which are more electronegative than any previously studied Fds in which two [4Fe-4S] clusters display a single transition. Further spectroscopic studies indicated that the CD spectrum of oxidized Fd I closely resembled that of Fd II; however, both spectra appeared to be unique relative to ferredoxins studied previously. Double integration of the EPR signal of the two Fds yielded approximately approximately 2.0 spins per molecule, compatible with the idea that C. tepidum Fd I and Fd II accept 2 electrons upon reduction. These results suggest that the C. tepidum Fd I and Fd II polypeptides each contain two bound [4Fe-4S] clusters. C. tepidum Fd I and Fd II are novel 2[4Fe-4S] Fds, which were shown previously to function as biological electron donors or acceptors for C. tepidum pyruvate synthase/pyruvate ferredoxin oxidoreductase (Yoon, K.-S., Hille, R., Hemann, C. F., and Tabita, F. R. (1999) J. Biol. Chem. 274, 29772-29778). Kinetic measurements indicated that Fd I had approximately 2.3-fold higher affinity than Fd II. The results of amino acid sequence alignments, molecular modeling, oxidation-reduction potentials, and spectral properties strongly indicate that the C. tepidum Fds are chimeras of both clostridial-type and chromatium-type Fds, suggesting that the two Fds are likely intermediates in the evolutional development of 2[4Fe-4S] clusters compared with the well described clostridial and chromatium types.
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Affiliation(s)
- K S Yoon
- Department of Microbiology, Plant Molecular Biology/Biotechnology Program, Protein Research Group, the Ohio State University, Columbus, Ohio 43210-1292, USA
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Ishii M, Yoon KS, Ueda Y, Ochiai T, Yun N, Takishita S, Kodama T, Igarashi Y. Reductive TCA cycle in an aerobic bacterium, Hydrogenobacter thermophilus strain TK-6. STUDIES IN SURFACE SCIENCE AND CATALYSIS 1998. [DOI: 10.1016/s0167-2991(98)80834-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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