1
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Brenzinger K, Glatter T, Hakobyan A, Meima-Franke M, Zweers H, Liesack W, Bodelier PLE. Exploring modes of microbial interactions with implications for methane cycling. FEMS Microbiol Ecol 2024; 100:fiae112. [PMID: 39122657 PMCID: PMC11370633 DOI: 10.1093/femsec/fiae112] [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: 05/06/2024] [Revised: 07/29/2024] [Accepted: 08/08/2024] [Indexed: 08/12/2024] Open
Abstract
Methanotrophs are the sole biological sink of methane. Volatile organic compounds (VOCs) produced by heterotrophic bacteria have been demonstrated to be a potential modulating factor of methane consumption. Here, we identify and disentangle the impact of the volatolome of heterotrophic bacteria on the methanotroph activity and proteome, using Methylomonas as model organism. Our study unambiguously shows how methanotrophy can be influenced by other organisms without direct physical contact. This influence is mediated by VOCs (e.g. dimethyl-polysulphides) or/and CO2 emitted during respiration, which can inhibit growth and methane uptake of the methanotroph, while other VOCs had a stimulating effect on methanotroph activity. Depending on whether the methanotroph was exposed to the volatolome of the heterotroph or to CO2, proteomics revealed differential protein expression patterns with the soluble methane monooxygenase being the most affected enzyme. The interaction between methanotrophs and heterotrophs can have strong positive or negative effects on methane consumption, depending on the species interacting with the methanotroph. We identified potential VOCs involved in the inhibition while positive effects may be triggered by CO2 released by heterotrophic respiration. Our experimental proof of methanotroph-heterotroph interactions clearly calls for detailed research into strategies on how to mitigate methane emissions.
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Affiliation(s)
- Kristof Brenzinger
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Timo Glatter
- Core Facility for Mass Spectrometry and Proteomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | - Anna Hakobyan
- Research group of Methanotrophic Bacteria, and Environmental Genomics/Transcriptomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
- Institute of Crop Science and Resource Conservation (INRES)
, Molecular Biology of the Rhizosphere, Nussallee 13, 53115 Bonn, Germany
| | - Marion Meima-Franke
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Hans Zweers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Werner Liesack
- Research group of Methanotrophic Bacteria, and Environmental Genomics/Transcriptomics, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | - Paul L E Bodelier
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
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2
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Cupples AM, Dang H, Foss K, Bernstein A, Thelusmond JR. An investigation of soil and groundwater metagenomes for genes encoding soluble and particulate methane monooxygenase, toluene-4-monoxygenase, propane monooxygenase and phenol hydroxylase. Arch Microbiol 2024; 206:363. [PMID: 39073473 DOI: 10.1007/s00203-024-04088-z] [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: 03/27/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 07/30/2024]
Abstract
Soil and groundwater were investigated for the genes encoding soluble and particulate methane monooxygenase/ammonia monooxygenase (sMMO, pMMO/AMO), toluene 4-monooxygenase (T4MO), propane monooxygenase (PMO) and phenol hydroxylase (PH). The objectives were (1) to determine which subunits were present, (2) to examine the diversity of the phylotypes associated with the biomarkers and (3) to identify which metagenome associated genomes (MAGs) contained these subunits. All T4MO and PH subunits were annotated in the groundwater metagenomes, while few were annotated in the soil metagenomes. The majority of the soil metagenomes included only four sMMO subunits. Only two groundwater metagenomes contained five sMMO subunits. Gene counts for the pMMO subunits varied between samples. The majority of the soil metagenomes were annotated for all four PMO subunits, while three out of eight groundwater metagenomes contained all four PMO subunits. A comparison of the blast alignments for the sMMO alpha chain (mmoX) indicated the phylotypes differed between the soil and groundwater metagenomes. For the pMMO/AMO alpha subunit (pmoA/amoA), Nitrosospira was important for the soil metagenomes, while Methylosinus and Methylocystis were dominant for the groundwater metagenomes. The majority of pmoA alignments from both metagenomes were from uncultured bacteria. High quality MAGs were obtained from the groundwater data. Four MAGs (Methylocella and Cypionkella) contained sMMO subunits. Another three MAGs, within the order Pseudomonadales, contained all three pMMO subunits. All PH subunits were detected in seven MAGs (Azonexus, Rhodoferax, Aquabacterium). In those seven, all contained catechol 2,3-dioxagenase, and Aquabacterium also contained catechol 1,2-dioxygenase. T4MO subunits were detected in eight MAGs (Azonexus, Rhodoferax, Siculibacillus) and all, except one, contained all six subunits. Four MAGs (Rhodoferax and Azonexus) contained all subunits for PH and T4MO, as well as catechol 2,3-dixoygenase. The detection of T4MO and PH in groundwater metagenomes and MAGs has important implications for the potential oxidation of groundwater contaminants.
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Affiliation(s)
- Alison M Cupples
- Department of Civil and Environmental Engineering, Michigan State University, A135, 1449 Engineering Research Court, East Lansing, MI, 48824, USA.
| | - Hongyu Dang
- Department of Civil and Environmental Engineering, Michigan State University, A135, 1449 Engineering Research Court, East Lansing, MI, 48824, USA
| | - Katy Foss
- Department of Civil and Environmental Engineering, Michigan State University, A135, 1449 Engineering Research Court, East Lansing, MI, 48824, USA
| | - Anat Bernstein
- Zuckerberg Institute for Water Research, Ben Gurion University of the Negev, Beersheba, Israel
| | - Jean-Rene Thelusmond
- Department of Civil and Environmental Engineering, Michigan State University, A135, 1449 Engineering Research Court, East Lansing, MI, 48824, USA
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3
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Bicaldo IEC, Padilla KSAR, Tu TH, Chen WT, Mendoza-Pascual MU, Vicera CVB, de Leon JR, Poblete KN, Austria ES, Lopez MLD, Kobayashi Y, Shiah FK, Papa RDS, Okuda N, Wang PL, Lin LH. The methane-oxidizing microbial communities of three maar lakes in tropical monsoon Asia. Front Microbiol 2024; 15:1410666. [PMID: 39044952 PMCID: PMC11263035 DOI: 10.3389/fmicb.2024.1410666] [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: 04/01/2024] [Accepted: 05/21/2024] [Indexed: 07/25/2024] Open
Abstract
Methane-oxidizing bacteria (MOB) is a group of planktonic microorganisms that use methane as their primary source of cellular energy. For tropical lakes in monsoon Asia, there is currently a knowledge gap on MOB community diversity and the factors influencing their abundance. Herewith, we present a preliminary assessment of the MOB communities in three maar lakes in tropical monsoon Asia using Catalyzed Reporter Deposition, Fluorescence In-Situ Hybridization (CARD-FISH), 16S rRNA amplicon sequencing, and pmoA gene sequencing. Correlation analysis between MOB abundances and lakes' physicochemical parameters following seasonal monsoon events were performed to explain observed spatial and temporal patterns in MOB diversity. The CARD-FISH analyses detected the three MOB types (I, II, and NC10) which aligned with the results from 16S rRNA amplicons and pmoA gene sequencing. Among community members based on 16S rRNA genes, Proteobacterial Type I MOB (e.g., Methylococcaceae and Methylomonadaceae), Proteobacterial Type II (Methylocystaceae), Verrucomicrobial (Methylacidiphilaceae), Methylomirabilota/NC10 (Methylomirabilaceae), and archaeal ANME-1a were found to be the dominant methane-oxidizers in three maar lakes. Analysis of microbial diversity and distribution revealed that the community compositions in Lake Yambo vary with the seasons and are more distinct during the stratified period. Temperature, DO, and pH were significantly and inversely linked with type I MOB and Methylomirabilota during stratification. Only MOB type I was influenced by monsoon changes. This research sought to establish a baseline for the diversity and ecology of planktonic MOB in tropical monsoon Asia to better comprehend their contribution to the CH4 cycle in tropical freshwater ecosystems.
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Affiliation(s)
- Iona Eunice C. Bicaldo
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
| | - Karol Sophia Agape R. Padilla
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Philippine Genome Center, University of the Philippines, Quezon City, Philippines
- Department of Science and Technology, Science Education Institute, Taguig, Philippines
| | - Tzu-Hsuan Tu
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
- Department of Oceanography, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Wan Ting Chen
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
| | - Milette U. Mendoza-Pascual
- Department of Environmental Science, School of Science and Engineering, Ateneo Research Institute for Science and Engineering, Ateneo de Manila University, Quezon City, Philippines
| | | | - Justine R. de Leon
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
- Department of Biological Sciences, University of Santo Tomas, Manila, Philippines
| | | | | | - Mark Louie D. Lopez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Yuki Kobayashi
- Center for Ecological Research, Kyoto University, Shiga, Japan
| | - Fuh-Kwo Shiah
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - Rey Donne S. Papa
- The Graduate School, University of Santo Tomas, Manila, Philippines
- Research Center for the Natural and Applied Sciences, University of Santo Tomas, Manila, Philippines
- Department of Biological Sciences, University of Santo Tomas, Manila, Philippines
| | - Noboru Okuda
- Center for Ecological Research, Kyoto University, Shiga, Japan
- Research Center for Inland Seas, Kobe University, Kobe, Japan
- Research Institute for Humanity and Nature, Kamigamo Motoyama, Kita Ward, Kyoto, Japan
| | - Pei-Ling Wang
- Institute of Oceanography, National Taiwan University, Taipei, Taiwan
- Research Center for Future Earth, National Taiwan University, Taipei, Taiwan
| | - Li-Hung Lin
- Department of Geosciences, National Taiwan University, Taipei, Taiwan
- Research Center for Future Earth, National Taiwan University, Taipei, Taiwan
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4
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Yu Y, Shi Y, Kwon YW, Choi Y, Kim Y, Na JG, Huh J, Lee J. A rationally designed miniature of soluble methane monooxygenase enables rapid and high-yield methanol production in Escherichia coli. Nat Commun 2024; 15:4399. [PMID: 38782897 PMCID: PMC11116448 DOI: 10.1038/s41467-024-48671-w] [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: 10/02/2023] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
Soluble methane monooxygenase (sMMO) oxidizes a wide range of carbon feedstocks (C1 to C8) directly using intracellular NADH and is a useful means in developing green routes for industrial manufacturing of chemicals. However, the high-throughput biosynthesis of active recombinant sMMO and the ensuing catalytic oxidation have so far been unsuccessful due to the structural and functional complexity of sMMO, comprised of three functionally complementary components, which remains a major challenge for its industrial applications. Here we develop a catalytically active miniature of sMMO (mini-sMMO), with a turnover frequency of 0.32 s-1, through an optimal reassembly of minimal and modified components of sMMO on catalytically inert and stable apoferritin scaffold. We characterise the molecular characteristics in detail through in silico and experimental analyses and verifications. Notably, in-situ methanol production in a high-cell-density culture of mini-sMMO-expressing recombinant Escherichia coli resulted in higher yield and productivity (~ 3.0 g/L and 0.11 g/L/h, respectively) compared to traditional methanotrophic production.
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Affiliation(s)
- Yeonhwa Yu
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Yongfan Shi
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - Young Wan Kwon
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Yoobin Choi
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Yusik Kim
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 04107, Republic of Korea
| | - June Huh
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea.
| | - Jeewon Lee
- Department of Chemical and Biological Engineering, Korea University, Anam-Dong 5-1, Seongbuk-Gu, Seoul, 02841, Republic of Korea.
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5
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Speijer D. How mitochondrial cristae illuminate the important role of oxygen during eukaryogenesis. Bioessays 2024; 46:e2300193. [PMID: 38449346 DOI: 10.1002/bies.202300193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/15/2024] [Accepted: 02/19/2024] [Indexed: 03/08/2024]
Abstract
Inner membranes of mitochondria are extensively folded, forming cristae. The observed overall correlation between efficient eukaryotic ATP generation and the area of internal mitochondrial inner membranes both in unicellular organisms and metazoan tissues seems to explain why they evolved. However, the crucial use of molecular oxygen (O2) as final acceptor of the electron transport chain is still not sufficiently appreciated. O2 was an essential prerequisite for cristae development during early eukaryogenesis and could be the factor allowing cristae retention upon loss of mitochondrial ATP generation. Here I analyze illuminating bacterial and unicellular eukaryotic examples. I also discuss formative influences of intracellular O2 consumption on the evolution of the last eukaryotic common ancestor (LECA). These considerations bring about an explanation for the many genes coming from other organisms than the archaeon and bacterium merging at the start of eukaryogenesis.
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Affiliation(s)
- Dave Speijer
- Medical Biochemistry, Amsterdam UMC location, University of Amsterdam, Amsterdam, The Netherlands
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6
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Patil SK, Islam T, Tveit A, Hodson A, Øvreås L. Targeting methanotrophs and isolation of a novel psychrophilic Methylobacter species from a terrestrial Arctic alkaline methane seep in Lagoon Pingo, Central Spitsbergen (78° N). Antonie Van Leeuwenhoek 2024; 117:60. [PMID: 38517574 PMCID: PMC10959801 DOI: 10.1007/s10482-024-01953-1] [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: 10/09/2023] [Accepted: 02/19/2024] [Indexed: 03/24/2024]
Abstract
The microbial diversity associated with terrestrial groundwater seepage through permafrost soils is tightly coupled to the geochemistry of these fluids. Terrestrial alkaline methane seeps from Lagoon Pingo, Central Spitsbergen (78°N) in Norway, with methane-saturated and oxygen-limited groundwater discharge providing a potential habitat for methanotrophy. Here, we report on the microbial community's comparative analyses and distribution patterns at two sites close to Lagoon Pingo's methane emission source. To target methane-oxidizing bacteria from this system, we analysed the microbial community pattern of replicate samples from two sections near the main methane seepage source. DNA extraction, metabarcoding and subsequent sequencing of 16S rRNA genes revealed microbial communities where the major prokaryotic phyla were Pseudomonadota (42-47%), Gemmatimonadota (4-14%) and Actinobacteriota (7-11%). Among the Pseudomonadota, members of the genus Methylobacter were present at relative abundances between 1.6 and 4.7%. Enrichment targeting the methane oxidising bacteria was set up using methane seep sediments as inoculum and methane as the sole carbon and energy source, and this resulted in the isolation of a novel psychrophilic methane oxidizer, LS7-T4AT. The optimum growth temperature for the isolate was 13 °C and the pH optimum was 8.0. The morphology of cells was short rods, and TEM analysis revealed intracytoplasmic membranes arranged in stacks, a distinctive feature for Type I methanotrophs in the family Methylomonadaceae of the class Gammaproteobacteria. The strain belongs to the genus Methylobacter based on high 16S rRNA gene similarity to the psychrophilic species of Methylobacter psychrophilus Z-0021T (98.95%), the psychrophilic strain Methylobacter sp. strain S3L5C (99.00%), and the Arctic mesophilic species of Methylobacter tundripaludum SV96T (99.06%). The genome size of LS7-T4AT was 4,338,157 bp with a G + C content of 47.93%. The average nucleotide identities (ANIb) of strain LS7-T4AT to 10 isolated strains of genus Methylobacter were between 75.54 and 85.51%, lower than the species threshold of 95%. The strain LS7-T4AT represents a novel Arctic species, distinct from other members of the genus Methylobacter, for which the name Methylobacter svalbardensis sp. nov. is proposed. The type of strain is LS7-T4AT (DSMZ:114308, JCM:39463).
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Affiliation(s)
- Shalaka K Patil
- Department of Biological Sciences, University of Bergen, Postboks 7803, 5020, Bergen, Norway.
| | - Tajul Islam
- Department of Biological Sciences, University of Bergen, Postboks 7803, 5020, Bergen, Norway
| | - Alexander Tveit
- Department of Arctic and Marine Biology, The Arctic University of Tromsø, 9037, Tromsø, Norway
| | - Andrew Hodson
- University Centre in Svalbard, 9171, Longyearbyen, Norway
| | - Lise Øvreås
- Department of Biological Sciences, University of Bergen, Postboks 7803, 5020, Bergen, Norway
- University Centre in Svalbard, 9171, Longyearbyen, Norway
- Bjerknes Centre for Climate Research, Jahnebakken 5, 5007, Bergen, Norway
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7
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Liu C, Schmitz RA, Pol A, Hogendoorn C, Verhagen D, Peeters SH, van Alen TA, Cremers G, Mesman RA, Op den Camp HJM. Active coexistence of the novel gammaproteobacterial methanotroph 'Ca. Methylocalor cossyra' CH1 and verrucomicrobial methanotrophs in acidic, hot geothermal soil. Environ Microbiol 2024; 26:e16602. [PMID: 38454738 DOI: 10.1111/1462-2920.16602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/16/2024] [Indexed: 03/09/2024]
Abstract
Terrestrial geothermal ecosystems are hostile habitats, characterized by large emissions of environmentally relevant gases such as CO2 , CH4 , H2 S and H2 . These conditions provide a niche for chemolithoautotrophic microorganisms. Methanotrophs of the phylum Verrucomicrobia, which inhabit these ecosystems, can utilize these gases and grow at pH levels below 1 and temperatures up to 65°C. In contrast, methanotrophs of the phylum Proteobacteria are primarily found in various moderate environments. Previously, novel verrucomicrobial methanotrophs were detected and isolated from the geothermal soil of the Favara Grande on the island of Pantelleria, Italy. The detection of pmoA genes, specific for verrucomicrobial and proteobacterial methanotrophs in this environment, and the partially overlapping pH and temperature growth ranges of these isolates suggest that these distinct phylogenetic groups could coexist in the environment. In this report, we present the isolation and characterization of a thermophilic and acid-tolerant gammaproteobacterial methanotroph (family Methylococcaceae) from the Favara Grande. This isolate grows at pH values ranging from 3.5 to 7.0 and temperatures from 35°C to 55°C, and diazotrophic growth was demonstrated. Its genome contains genes encoding particulate and soluble methane monooxygenases, XoxF- and MxaFI-type methanol dehydrogenases, and all enzymes of the Calvin cycle. For this novel genus and species, we propose the name 'Candidatus Methylocalor cossyra' CH1.
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Affiliation(s)
- Changqing Liu
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Rob A Schmitz
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Arjan Pol
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Carmen Hogendoorn
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Daniël Verhagen
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Theo A van Alen
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Geert Cremers
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Rob A Mesman
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Faculty of Science, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, the Netherlands
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8
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Tucci FJ, Rosenzweig AC. Direct Methane Oxidation by Copper- and Iron-Dependent Methane Monooxygenases. Chem Rev 2024; 124:1288-1320. [PMID: 38305159 PMCID: PMC10923174 DOI: 10.1021/acs.chemrev.3c00727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Methane is a potent greenhouse gas that contributes significantly to climate change and is primarily regulated in Nature by methanotrophic bacteria, which consume methane gas as their source of energy and carbon, first by oxidizing it to methanol. The direct oxidation of methane to methanol is a chemically difficult transformation, accomplished in methanotrophs by complex methane monooxygenase (MMO) enzyme systems. These enzymes use iron or copper metallocofactors and have been the subject of detailed investigation. While the structure, function, and active site architecture of the copper-dependent particulate methane monooxygenase (pMMO) have been investigated extensively, its putative quaternary interactions, regulation, requisite cofactors, and mechanism remain enigmatic. The iron-dependent soluble methane monooxygenase (sMMO) has been characterized biochemically, structurally, spectroscopically, and, for the most part, mechanistically. Here, we review the history of MMO research, focusing on recent developments and providing an outlook for future directions of the field. Engineered biological catalysis systems and bioinspired synthetic catalysts may continue to emerge along with a deeper understanding of the molecular mechanisms of biological methane oxidation. Harnessing the power of these enzymes will necessitate combined efforts in biochemistry, structural biology, inorganic chemistry, microbiology, computational biology, and engineering.
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Affiliation(s)
- Frank J Tucci
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Amy C Rosenzweig
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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9
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Lim J, Wehmeyer H, Heffner T, Aeppli M, Gu W, Kim PJ, Horn MA, Ho A. Resilience of aerobic methanotrophs in soils; spotlight on the methane sink under agriculture. FEMS Microbiol Ecol 2024; 100:fiae008. [PMID: 38327184 PMCID: PMC10872700 DOI: 10.1093/femsec/fiae008] [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: 09/05/2023] [Revised: 01/19/2024] [Accepted: 02/06/2024] [Indexed: 02/09/2024] Open
Abstract
Aerobic methanotrophs are a specialized microbial group, catalyzing the oxidation of methane. Disturbance-induced loss of methanotroph diversity/abundance, thus results in the loss of this biological methane sink. Here, we synthesized and conceptualized the resilience of the methanotrophs to sporadic, recurring, and compounded disturbances in soils. The methanotrophs showed remarkable resilience to sporadic disturbances, recovering in activity and population size. However, activity was severely compromised when disturbance persisted or reoccurred at increasing frequency, and was significantly impaired following change in land use. Next, we consolidated the impact of agricultural practices after land conversion on the soil methane sink. The effects of key interventions (tillage, organic matter input, and cover cropping) where much knowledge has been gathered were considered. Pairwise comparisons of these interventions to nontreated agricultural soils indicate that the agriculture-induced impact on the methane sink depends on the cropping system, which can be associated to the physiology of the methanotrophs. The impact of agriculture is more evident in upland soils, where the methanotrophs play a more prominent role than the methanogens in modulating overall methane flux. Although resilient to sporadic disturbances, the methanotrophs are vulnerable to compounded disturbances induced by anthropogenic activities, significantly affecting the methane sink function.
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Affiliation(s)
- Jiyeon Lim
- Institute for Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Helena Wehmeyer
- Nestlè Research, Route du Jorat 57, CH 1000 Lausanne 26, Switzerland
| | - Tanja Heffner
- Institute for Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Meret Aeppli
- Environmental Engineering Institute IIE-ENAC, Laboratory SOIL, Ecole Polytechnique Fédérale de Lausanne (EPFL), Valais Wallis, CH 1950 Sion, Switzerland
| | - Wenyu Gu
- Environmental Engineering Institute IIE-ENAC, Laboratory MICROBE, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH 1015 Lausanne, Switzerland
| | - Pil Joo Kim
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Marcus A Horn
- Institute for Microbiology, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Adrian Ho
- Nestlè Research, Route du Jorat 57, CH 1000 Lausanne 26, Switzerland
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10
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Seppey CVW, Cabrol L, Thalasso F, Gandois L, Lavergne C, Martinez-Cruz K, Sepulveda-Jauregui A, Aguilar-Muñoz P, Astorga-España MS, Chamy R, Dellagnezze BM, Etchebehere C, Fochesatto GJ, Gerardo-Nieto O, Mansilla A, Murray A, Sweetlove M, Tananaev N, Teisserenc R, Tveit AT, Van de Putte A, Svenning MM, Barret M. Biogeography of microbial communities in high-latitude ecosystems: Contrasting drivers for methanogens, methanotrophs and global prokaryotes. Environ Microbiol 2023; 25:3364-3386. [PMID: 37897125 DOI: 10.1111/1462-2920.16526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023]
Abstract
Methane-cycling is becoming more important in high-latitude ecosystems as global warming makes permafrost organic carbon increasingly available. We explored 387 samples from three high-latitudes regions (Siberia, Alaska and Patagonia) focusing on mineral/organic soils (wetlands, peatlands, forest), lake/pond sediment and water. Physicochemical, climatic and geographic variables were integrated with 16S rDNA amplicon sequences to determine the structure of the overall microbial communities and of specific methanogenic and methanotrophic guilds. Physicochemistry (especially pH) explained the largest proportion of variation in guild composition, confirming species sorting (i.e., environmental filtering) as a key mechanism in microbial assembly. Geographic distance impacted more strongly beta diversity for (i) methanogens and methanotrophs than the overall prokaryotes and, (ii) the sediment habitat, suggesting that dispersal limitation contributed to shape the communities of methane-cycling microorganisms. Bioindicator taxa characterising different ecological niches (i.e., specific combinations of geographic, climatic and physicochemical variables) were identified, highlighting the importance of Methanoregula as generalist methanogens. Methylocystis and Methylocapsa were key methanotrophs in low pH niches while Methylobacter and Methylomonadaceae in neutral environments. This work gives insight into the present and projected distribution of methane-cycling microbes at high latitudes under climate change predictions, which is crucial for constraining their impact on greenhouse gas budgets.
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Affiliation(s)
- Christophe V W Seppey
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
- Institute of Environmental Science and Geography, University of Potsdam, Potsdam-Golm, Germany
| | - Léa Cabrol
- Aix-Marseille University, CNRS, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Marseille, France
- Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile
| | - Frederic Thalasso
- Centro de Investigacíon y de Estudios Avanzados del Instituto Politecnico Nacional (Cinvestav-IPN), Departamento de Biotecnología y Bioingeniería, México, Mexico
| | - Laure Gandois
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Céline Lavergne
- HUB AMBIENTAL UPLA, Laboratory of Aquatic Environmental Research, Universidad de Playa Ancha, Valparaíso, Chile
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Karla Martinez-Cruz
- Departamento de Ciencias y Recursos Naturales, Universidad de Magallanes, Punta Arenas, Chile
- Environmental Physics Group, Limnological Institute, University of Konstanz, Konstanz, Germany
| | | | - Polette Aguilar-Muñoz
- HUB AMBIENTAL UPLA, Laboratory of Aquatic Environmental Research, Universidad de Playa Ancha, Valparaíso, Chile
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | | | - Rolando Chamy
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Bruna Martins Dellagnezze
- Microbial Ecology Laboratory, Department of Microbial Biochemistry and Genomic, Biological Research Institute "Clemente Estable", Montevideo, Uruguay
| | - Claudia Etchebehere
- Microbial Ecology Laboratory, Department of Microbial Biochemistry and Genomic, Biological Research Institute "Clemente Estable", Montevideo, Uruguay
| | - Gilberto J Fochesatto
- Department of Atmospheric Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Oscar Gerardo-Nieto
- Centro de Investigacíon y de Estudios Avanzados del Instituto Politecnico Nacional (Cinvestav-IPN), Departamento de Biotecnología y Bioingeniería, México, Mexico
| | - Andrés Mansilla
- Departamento de Ciencias y Recursos Naturales, Universidad de Magallanes, Punta Arenas, Chile
| | - Alison Murray
- Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, Nevada, USA
| | - Maxime Sweetlove
- Royal Belgian Institute for Natural Sciences, OD-Nature, Brussels, Belgium
| | - Nikita Tananaev
- Melnikov Permafrost Institute, Russian Academy of Sciences, Yakutsk, Russia
- Institute of Natural Sciences, North-Eastern Federal University, Yakutsk, Russia
| | - Roman Teisserenc
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Alexander T Tveit
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Anton Van de Putte
- Royal Belgian Institute for Natural Sciences, OD-Nature, Brussels, Belgium
| | - Mette M Svenning
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Maialen Barret
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
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11
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Shinjo R, Oe F, Nakagawa K, Murase J, Asakawa S, Watanabe T. Type-specific quantification of particulate methane monooxygenase gene of methane-oxidizing bacteria at the oxic-anoxic interface of a surface paddy soil by digital PCR. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:392-403. [PMID: 37078408 PMCID: PMC10472520 DOI: 10.1111/1758-2229.13155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/10/2023] [Indexed: 05/03/2023]
Abstract
Aerobic methane-oxidizing bacteria (MOB) play an important role in mitigating methane emissions from paddy fields. In this study, we developed a differential quantification method for the copy number of pmoA genes of type Ia, Ib, and IIa MOB in paddy field soil using chip-based digital PCR. Three probes specific to the pmoA of type Ia, Ib, and IIa MOB worked well in digital PCR quantification when genomic DNA of MOB isolates and PCR-amplified DNA fragments of pmoA were examined as templates. When pmoA genes in the surface soil layer of a flooded paddy were quantified by digital PCR, the copy numbers of type Ia, Ib, and IIa MOB were 105 -106 , 105 -106 , and 107 copies g-1 dry soil, respectively, with the highest values in the top 0-2-mm soil layer. Especially, the copy numbers of type Ia and Ib MOB increased by 240% and 380% at the top layer after soil flooding, suggesting that the soil circumstances at the oxic-anoxic interfaces were more preferential for growth of type I MOB than type II MOB. Thus, type I MOB likely play an important role in the methane consumption at the surface paddy soil.
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Affiliation(s)
- Rina Shinjo
- Graduate School of Bioagricultural SciencesNagoya University, ChikusaNagoya464‐8601Japan
| | - Fumika Oe
- Graduate School of Bioagricultural SciencesNagoya University, ChikusaNagoya464‐8601Japan
| | - Koki Nakagawa
- School of Agricultural SciencesNagoya University, ChikusaNagoya464‐8601Japan
| | - Jun Murase
- Graduate School of Bioagricultural SciencesNagoya University, ChikusaNagoya464‐8601Japan
| | - Susumu Asakawa
- Graduate School of Bioagricultural SciencesNagoya University, ChikusaNagoya464‐8601Japan
| | - Takeshi Watanabe
- Graduate School of Bioagricultural SciencesNagoya University, ChikusaNagoya464‐8601Japan
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12
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Houghton KM, Carere CR, Stott MB, McDonald IR. Thermophilic methane oxidation is widespread in Aotearoa-New Zealand geothermal fields. Front Microbiol 2023; 14:1253773. [PMID: 37720161 PMCID: PMC10502179 DOI: 10.3389/fmicb.2023.1253773] [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: 07/06/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023] Open
Abstract
Geothermal areas represent substantial point sources for greenhouse gas emissions such as methane. While it is known that methanotrophic microorganisms act as a biofilter, decreasing the efflux of methane in most soils to the atmosphere, the diversity and the extent to which methane is consumed by thermophilic microorganisms in geothermal ecosystems has not been widely explored. To determine the extent of biologically mediated methane oxidation at elevated temperatures, we set up 57 microcosms using soils from 14 Aotearoa-New Zealand geothermal fields and show that moderately thermophilic (>40°C) and thermophilic (>60°C) methane oxidation is common across the region. Methane oxidation was detected in 54% (n = 31) of the geothermal soil microcosms tested at temperatures up to 75°C (pH 1.5-8.1), with oxidation rates ranging from 0.5 to 17.4 μmol g-1 d-1 wet weight. The abundance of known aerobic methanotrophs (up to 60.7% Methylacidiphilum and 11.2% Methylothermus) and putative anaerobic methanotrophs (up to 76.7% Bathyarchaeota) provides some explanation for the rapid rates of methane oxidation observed in microcosms. However, not all methane oxidation was attributable to known taxa; in some methane-consuming microcosms we detected methanotroph taxa in conditions outside of their known temperature range for growth, and in other examples, we observed methane oxidation in the absence of known methanotrophs through 16S rRNA gene sequencing. Both of these observations suggest unidentified methane oxidizing microorganisms or undescribed methanotrophic syntrophic associations may also be present. Subsequent enrichment cultures from microcosms yielded communities not predicted by the original diversity studies and showed rates inconsistent with microcosms (≤24.5 μmol d-1), highlighting difficulties in culturing representative thermophilic methanotrophs. Finally, to determine the active methane oxidation processes, we attempted to elucidate metabolic pathways from two enrichment cultures actively oxidizing methane using metatranscriptomics. The most highly expressed genes in both enrichments (methane monooxygenases, methanol dehydrogenases and PqqA precursor peptides) were related to methanotrophs from Methylococcaceae, Methylocystaceae and Methylothermaceae. This is the first example of using metatranscriptomics to investigate methanotrophs from geothermal environments and gives insight into the metabolic pathways involved in thermophilic methanotrophy.
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Affiliation(s)
- Karen M. Houghton
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Aka Mātuatua | School of Science, Te Whare Wānanga o Waikato | University of Waikato, Hamilton, New Zealand
| | - Carlo R. Carere
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Tari Pūhanga Tukanga Matū | Department of Chemical and Process Engineering, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, New Zealand
| | - Matthew B. Stott
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Kura Pūtaiao Koiora | School of Biological Sciences, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, New Zealand
| | - Ian R. McDonald
- Te Aka Mātuatua | School of Science, Te Whare Wānanga o Waikato | University of Waikato, Hamilton, New Zealand
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13
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Jensen S, Siljanen HM, Dörsch P. Activity and abundance of methanotrophic bacteria in a northern mountainous gradient of wetlands. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023; 15:206-215. [PMID: 36786058 PMCID: PMC10464705 DOI: 10.1111/1758-2229.13137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 11/23/2022] [Indexed: 05/06/2023]
Abstract
Methane uptake and diversity of methanotrophic bacteria was investigated across six hydrologically connected wetlands in a mountainous forest landscape upstream of lake Langtjern, southern Norway. From floodplain through shrubs, forest and sedges to a Sphagnum covered site, growing season CH4 production was insufficiently consumed to balance release into the atmosphere. Emission increased by soil moisture ranging 0.6-6.8 mg CH4 m-2 h-1 . Top soils of all sites consumed CH4 including at the lowest 78 ppmv CH4 supplied, thus potentially oxidizing 17-51 nmol CH4 g-1 dw h-1 , with highest Vmax 440 nmol g-1 dw h-1 under Sphagnum and lowest Km 559 nM under hummocked Carex. Nine genera and several less understood type I and type II methanotrophs were detected by the key functional gene pmoA involved in methane oxidation. Microarray signal intensities from all sites revealed Methylococcus, the affiliated Lake Washington cluster, Methylocaldum, a Japanese rice cluster, Methylosinus, Methylocystis and the affiliated Peat264 cluster. Notably enriched by site was a floodplain Methylomonas and a Methylocapsa-affiliated watershed cluster in the Sphagnum site. The climate sensitive water table was shown to be a strong controlling factor highlighting its link with the CH4 cycle in elevated wetlands.
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Affiliation(s)
- Sigmund Jensen
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Henri M.P. Siljanen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Peter Dörsch
- Norwegian University of Life SciencesFaculty for Environmental Sciences and Natural Resource ManagementNorway
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14
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Cre/ lox-Mediated CRISPRi Library Reveals Core Genome of a Type I Methanotroph Methylotuvimicrobium buryatense 5GB1C. Appl Environ Microbiol 2023; 89:e0188322. [PMID: 36622175 PMCID: PMC9888281 DOI: 10.1128/aem.01883-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Methanotrophs play key roles in global methane cycling and are promising platforms for methane bioconversion. However, major gaps existing in fundamental knowledge undermines understanding of these methane-consuming microorganisms. To associate genes with a phenotype at the genome-wide level, we developed a Cre/lox-mediated method for constructing a large-scale CRISPRi library in a model methanotroph Methylotuvimicrobium buryatense 5GB1C. The efficiency of this Cre mediated integration method was up to a level of 105 CFU/μg DNA. Targeting 4,100 predicted protein-coding genes, our CRISPRi pooled screening uncovered 788 core genes for the growth of strain 5GB1C using methane. The core genes are highly consistent with the gene knockout results, indicating the reliability of the CRISPRi screen. Insights from the core genes include that annotated isozymes generally exist in metabolic pathways and many core genes are hypothetical genes. This work not only provides functional genomic data for both fundamental research and metabolic engineering of methanotrophs, but also offers a method for CRISPRi library construction. IMPORTANCE Due to their key role in methane cycling and their industrial potential, methanotrophs have drawn increasing attention. Genome-wide experimental approaches for gene-phenotype mapping accelerate our understanding and engineering of a bacterium. However, these approaches are still unavailable in methanotrophs. This work has two significant implications. First, the core genes identified here provide functional genetic basics for complete reconstruction of the metabolic network and afford more clues for knowledge gaps. Second, the Cre-mediated knock-in method developed in this work enables large-scale DNA library construction in methanotrophs; the CRISPRi library can be used to screen the genes associated with special culture conditions.
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15
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Yao X, Wang J, Hu B. How methanotrophs respond to pH: A review of ecophysiology. Front Microbiol 2023; 13:1034164. [PMID: 36687570 PMCID: PMC9853399 DOI: 10.3389/fmicb.2022.1034164] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 12/09/2022] [Indexed: 01/08/2023] Open
Abstract
Varying pH globally affects terrestrial microbial communities and biochemical cycles. Methanotrophs effectively mitigate methane fluxes in terrestrial habitats. Many methanotrophs grow optimally at neutral pH. However, recent discoveries show that methanotrophs grow in strongly acidic and alkaline environments. Here, we summarize the existing knowledge on the ecophysiology of methanotrophs under different pH conditions. The distribution pattern of diverse subgroups is described with respect to their relationship with pH. In addition, their responses to pH stress, consisting of structure-function traits and substrate affinity traits, are reviewed. Furthermore, we propose a putative energy trade-off model aiming at shedding light on the adaptation mechanisms of methanotrophs from a novel perspective. Finally, we take an outlook on methanotrophs' ecophysiology affected by pH, which would offer new insights into the methane cycle and global climate change.
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Affiliation(s)
- Xiangwu Yao
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China
| | - Jiaqi Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China
| | - Baolan Hu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, China,Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, China,*Correspondence: Baolan Hu ✉
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16
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Cupples AM, Li Z, Wilson FP, Ramalingam V, Kelly A. In silico analysis of soil, sediment and groundwater microbial communities to predict biodegradation potential. J Microbiol Methods 2022; 202:106595. [DOI: 10.1016/j.mimet.2022.106595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 12/27/2022]
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Abstract
Wetlands are the major natural source of methane, an important greenhouse gas. The sulfur and methane cycles in wetlands are linked—e.g., a strong sulfur cycle can inhibit methanogenesis. Although there has historically been a clear distinction drawn between methane and sulfur oxidizers, here, we isolated a methanotroph that also performed respiratory oxidization of sulfur compounds. We experimentally demonstrated that thiotrophy and methanotrophy are metabolically compatible, and both metabolisms could be expressed simultaneously in a single microorganism. These findings suggest that mixotrophic methane/sulfur-oxidizing bacteria are a previously overlooked component of environmental methane and sulfur cycles. This creates a framework for a better understanding of these redox cycles in natural and engineered wetlands. Natural and anthropogenic wetlands are major sources of the atmospheric greenhouse gas methane. Methane emissions from wetlands are mitigated by methanotrophic bacteria at the oxic–anoxic interface, a zone of intense redox cycling of carbon, sulfur, and nitrogen compounds. Here, we report on the isolation of an aerobic methanotrophic bacterium, ‘Methylovirgula thiovorans' strain HY1, which possesses metabolic capabilities never before found in any methanotroph. Most notably, strain HY1 is the first bacterium shown to aerobically oxidize both methane and reduced sulfur compounds for growth. Genomic and proteomic analyses showed that soluble methane monooxygenase and XoxF-type alcohol dehydrogenases are responsible for methane and methanol oxidation, respectively. Various pathways for respiratory sulfur oxidation were present, including the Sox–rDsr pathway and the S4I system. Strain HY1 employed the Calvin–Benson–Bassham cycle for CO2 fixation during chemolithoautotrophic growth on reduced sulfur compounds. Proteomic and microrespirometry analyses showed that the metabolic pathways for methane and thiosulfate oxidation were induced in the presence of the respective substrates. Methane and thiosulfate could therefore be independently or simultaneously oxidized. The discovery of this versatile bacterium demonstrates that methanotrophy and thiotrophy are compatible in a single microorganism and underpins the intimate interactions of methane and sulfur cycles in oxic–anoxic interface environments.
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Wang J, Chu YX, Schäfer H, Tian G, He R. CS 2 increasing CH 4-derived carbon emissions and active microbial diversity in lake sediments. ENVIRONMENTAL RESEARCH 2022; 208:112678. [PMID: 34999031 DOI: 10.1016/j.envres.2022.112678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/24/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Lakes are important methane (CH4) sources to the atmosphere, especially eutrophic lakes with cyanobacterial blooms accompanied by volatile sulfur compound (VSC) emissions. CH4 oxidation is a key strategy to mitigate CH4 emission from lakes. In this study, we characterized the fate of CH4-derived carbon and active microbial communities in lake sediments with CS2 used as a typical VSC, based on the investigation of CH4 and VSC fluxes from Meiliang Bay in Lake Taihu. Stable isotope probing microcosm incubation showed that the efficiency of CH4-derived carbon incorporated into organic matter was 21.1% in the sediment with CS2 existence, which was lower than that without CS2 (27.3%). SO42--S was the main product of CS2 oxidation under aerobic condition, accounting for 59.3-62.7% of the input CS2-S. CS2 and CH4 coexistence led to a decrease of methanotroph and methylotroph abundances and stimulated the production of extracellular polymeric substances. CS2 and its metabolites including total sulfur, SO42- and acid volatile sulfur acted as the main drivers influencing the active microbial community structure in the sediments. Compared with α-proteobacteria methanotrophs, γ-proteobacteria methanotrophs Methylomicrobium, Methylomonas, Crenothrix and Methylosarcina were more dominant in the sediments. CH4-derived carbon mainly flowed into methylotrophs in the first stage. With CH4 consumption, more CH4-derived carbon flowed into non-methylotrophs. CS2 could prompt more CH4-derived carbon flowing into non-methanotrophs and non-methylotrophs, such as sulfur-metabolizing bacteria. These findings can help elucidate the influence of VSCs on microorganisms and provide insights to carbon fluxes from eutrophic lake systems.
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Affiliation(s)
- Jing Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Yi-Xuan Chu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Hendrik Schäfer
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Guangming Tian
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo He
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China; College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China.
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Cai Y, Yun J, Jia Z. Phylogeny and Metabolic Potential of the Methanotrophic Lineage MO3 in Beijerinckiaceae from the Paddy Soil through Metagenome-Assembled Genome Reconstruction. Microorganisms 2022; 10:microorganisms10050955. [PMID: 35630399 PMCID: PMC9145241 DOI: 10.3390/microorganisms10050955] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/22/2022] [Accepted: 04/29/2022] [Indexed: 01/27/2023] Open
Abstract
Although the study of aerobic methane-oxidizing bacteria (MOB, methanotrophs) has been carried out for more than a hundred years, there are many uncultivated methanotrophic lineages whose metabolism is largely unknown. Here, we reconstructed a nearly complete genome of a Beijerinckiaceae methanotroph from the enrichment of paddy soil by using nitrogen-free M2 medium. The methanotroph labeled as MO3_YZ.1 had a size of 3.83 Mb, GC content of 65.6%, and 3442 gene-coding regions. Based on phylogeny of pmoA gene and genome and the genomic average nucleotide identity, we confirmed its affiliation to the MO3 lineage and a close relationship to Methylocapsa. MO3_YZ.1 contained mxaF- and xoxF-type methanol dehydrogenase. MO3_YZ.1 used the serine cycle to assimilate carbon and regenerated glyoxylate through the glyoxylate shunt as it contained isocitrate lyase and complete tricarboxylic acid cycle-coding genes. The ethylmalonyl-CoA pathway and Calvin–Benson–Bassham cycle were incomplete in MO3_YZ.1. Three acetate utilization enzyme-coding genes were identified, suggesting its potential ability to utilize acetate. The presence of genes for N2 fixation, sulfur transformation, and poly-β-hydroxybutyrate synthesis enable its survival in heterogeneous habitats with fluctuating supplies of carbon, nitrogen, and sulfur.
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Affiliation(s)
- Yuanfeng Cai
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Correspondence: (Y.C.); (Z.J.); Tel.: +86-25-8688-1850 (Y.C.); +86-25-8688-1311 (Z.J.)
| | - Juanli Yun
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China;
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Correspondence: (Y.C.); (Z.J.); Tel.: +86-25-8688-1850 (Y.C.); +86-25-8688-1311 (Z.J.)
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Samanta D, Govil T, Saxena P, Gadhamshetty V, Krumholz LR, Salem DR, Sani RK. Enhancement of Methane Catalysis Rates in Methylosinus trichosporium OB3b. Biomolecules 2022; 12:560. [PMID: 35454149 PMCID: PMC9024549 DOI: 10.3390/biom12040560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 02/05/2023] Open
Abstract
Particulate methane monooxygenase (pMMO), a membrane-bound enzyme having three subunits (α, β, and γ) and copper-containing centers, is found in most of the methanotrophs that selectively catalyze the oxidation of methane into methanol. Active sites in the pMMO of Methylosinus trichosporium OB3b were determined by docking the modeled structure with ethylbenzene, toluene, 1,3-dibutadiene, and trichloroethylene. The docking energy between the modeled pMMO structure and ethylbenzene, toluene, 1,3-dibutadiene, and trichloroethylene was -5.2, -5.7, -4.2, and -3.8 kcal/mol, respectively, suggesting the existence of more than one active site within the monomeric subunits due to the presence of multiple binding sites within the pMMO monomer. The evaluation of tunnels and cavities of the active sites and the docking results showed that each active site is specific to the radius of the substrate. To increase the catalysis rates of methane in the pMMO of M. trichosporium OB3b, selected amino acid residues interacting at the binding site of ethylbenzene, toluene, 1,3-dibutadiene, and trichloroethylene were mutated. Based on screening the strain energy, docking energy, and physiochemical properties, five mutants were downselected, B:Leu31Ser, B:Phe96Gly, B:Phe92Thr, B:Trp106Ala, and B:Tyr110Phe, which showed the docking energy of -6.3, -6.7, -6.3, -6.5, and -6.5 kcal/mol, respectively, as compared to the wild type (-5.2 kcal/mol) with ethylbenzene. These results suggest that these five mutants would likely increase methane oxidation rates compared to wild-type pMMO.
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Affiliation(s)
- Dipayan Samanta
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (D.S.); (T.G.); (P.S.); (D.R.S.)
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (V.G.); (L.R.K.)
| | - Tanvi Govil
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (D.S.); (T.G.); (P.S.); (D.R.S.)
- Composite and Nanocomposite Advanced Manufacturing-Biomaterials Center, Rapid City, SD 57701, USA
| | - Priya Saxena
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (D.S.); (T.G.); (P.S.); (D.R.S.)
| | - Venkata Gadhamshetty
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (V.G.); (L.R.K.)
- Department of Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA
| | - Lee R. Krumholz
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (V.G.); (L.R.K.)
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - David R. Salem
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (D.S.); (T.G.); (P.S.); (D.R.S.)
- Composite and Nanocomposite Advanced Manufacturing-Biomaterials Center, Rapid City, SD 57701, USA
| | - Rajesh K. Sani
- Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (D.S.); (T.G.); (P.S.); (D.R.S.)
- BuG ReMeDEE Consortium, South Dakota School of Mines and Technology, Rapid City, SD 57701, USA; (V.G.); (L.R.K.)
- Composite and Nanocomposite Advanced Manufacturing-Biomaterials Center, Rapid City, SD 57701, USA
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21
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Metabolic flexibility of aerobic methanotrophs under anoxic conditions in Arctic lake sediments. THE ISME JOURNAL 2022; 16:78-90. [PMID: 34244610 PMCID: PMC8692461 DOI: 10.1038/s41396-021-01049-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 06/19/2021] [Accepted: 06/23/2021] [Indexed: 02/06/2023]
Abstract
Methane (CH4) emissions from Arctic lakes are a large and growing source of greenhouse gas to the atmosphere with critical implications for global climate. Because Arctic lakes are ice covered for much of the year, understanding the metabolic flexibility of methanotrophs under anoxic conditions would aid in characterizing the mechanisms responsible for limiting CH4 emissions from high-latitude regions. Using sediments from an active CH4 seep in Lake Qalluuraq, Alaska, we conducted DNA-based stable isotope probing (SIP) in anoxic mesocosms and found that aerobic Gammaproteobacterial methanotrophs dominated in assimilating CH4. Aerobic methanotrophs were also detected down to 70 cm deep in sediments at the seep site, where anoxic conditions persist. Metagenomic analyses of the heavy DNA from 13CH4-SIP incubations showed that these aerobic methanotrophs had the capacity to generate intermediates such as methanol, formaldehyde, and formate from CH4 oxidation and to oxidize formaldehyde in the tetrahydromethanopterin (H4MPT)-dependent pathway under anoxic conditions. The high levels of Fe present in sediments, combined with Fe and CH4 profiles in the persistent CH4 seep site, suggested that oxidation of CH4, or, more specifically, its intermediates such as methanol and formaldehyde might be coupled to iron reduction. Aerobic methanotrophs also possessed genes associated with nitrogen and hydrogen metabolism, which might provide potentially alternative energy conservation options under anoxic conditions. These results expand the known metabolic spectrum of aerobic methanotrophs under anoxic conditions and necessitate the re-assessment of the mechanisms underlying CH4 oxidation in the Arctic, especially under lakes that experience extended O2 limitations during ice cover.
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22
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Cupples AM, Thelusmond JR. Predicting the occurrence of monooxygenases and their associated phylotypes in soil microcosms. METHODS IN MICROBIOLOGY 2021; 193:106401. [PMID: 34973287 DOI: 10.1016/j.mimet.2021.106401] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 10/19/2022]
Abstract
Cometabolic oxidation involves the oxidation of chemicals often by monooxygenases or dioxygenases and can be a removal process for environmental contaminants such as trichloroethene (TCE) or 1,4-dioxane. Information on the occurrence of these genes and their associated microorganisms in environmental samples has the potential to enhance our understanding of contaminant removal. The overall aims were to 1) ascertain which genes encoding for monooxygenases (from methanotrophs, ammonia oxidizing bacteria and toluene/phenol oxidizers) and other key enzymes are present in soil microcosms and 2) determine which phylotypes are associated with those genes. The approach involved a predictive tool called PICRUSt2 and 16S rRNA gene amplicon datasets from two previous soil microcosm studies. The following targets from the KEGG database were examined: pmo/amo, mmo, dmp/pox/tomA, tmo/tbu/tou, bssABC (and downstream genes), tod, xylM, xylA, gst, dhaA, catE, dbfA1, dbfA2 and phenol 2-monooxygenase. A large number of phylotypes were associated with pmo/amo, while mmo was linked to only five. Several phylotypes were associated with both pmo/amo and mmo. The most dominant microorganism predicted for mmoX was Mycobacterium (also predicted for pmo/amo). A large number of phylotypes were associated with all six genes from the dmp/pox/tomA KEGG group. The taxonomic associations predicted for the tmo/tbu/tou KEGG group were more limited. In both datasets, Geobacter was a key phylotype for benzylsuccinate synthase. The dioxygenase-mediated toluene degradation pathway encoded by todC1C2BA was largely absent, as were the genes (xylM, xylA) encoding for xylene monooxygenase. All other genes investigated were predicted to be present and were associated with a number of microorganisms. Overall, the analysis predicted the genes encoding for sMMO (mmo), T3MO/T3MO/ToMO (tmo/tbu/tou) and benzylsuccinate synthase (bssABC) are present for a limited number of phylotypes compared to those encoding for pMMO/AMO (pmo/amo) and phenol monooxygenase/T2MO (dmp/poxA/tomA). These findings suggest in soils contaminant removal via pMMO/AMO or phenol monooxygenase/T2MO may be common because of the occurrence of these enzymes with a large number of phylotypes.
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Affiliation(s)
- Alison M Cupples
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA.
| | - Jean-Rene Thelusmond
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA
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23
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Cheng XY, Liu XY, Wang HM, Su CT, Zhao R, Bodelier PLE, Wang WQ, Ma LY, Lu XL. USC γ Dominated Community Composition and Cooccurrence Network of Methanotrophs and Bacteria in Subterranean Karst Caves. Microbiol Spectr 2021; 9:e0082021. [PMID: 34406837 PMCID: PMC8552738 DOI: 10.1128/spectrum.00820-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 07/13/2021] [Indexed: 12/20/2022] Open
Abstract
Karst caves have recently been demonstrated to act as a sink for atmospheric methane, due in part to consumption by microbes residing in caves that can oxidize methane at atmospheric levels. However, our knowledge about the responsible atmospheric methane-oxidizing bacteria (atmMOB) in this vast habitat remains limited to date. To address this issue, weathered rock samples from three karst caves were collected in Guilin City and subjected to high-throughput sequencing of pmoA and 16S rRNA genes. The results showed that members of the high-affinity upland soil cluster (USC), especially upland soil cluster gamma (USCγ), with absolute abundances of 104 to 109 copies · g-1 dry sample, dominated the atmMOB communities, while Proteobacteria and Actinobacteria dominated the overall bacterial communities. Moreover, USCγ was a keystone taxon in cooccurrence networks of both the atmMOB and the total bacterial community, whereas keystone taxa in the bacterial network also included Gaiella and Aciditerrimonas. Positive links overwhelmingly dominated the cooccurrence networks of both atmMOB and the total bacterial community, indicating a consistent response to environmental disturbances. Our study shed new insights on the diversity and abundances underlining atmMOB and total bacterial communities and on microbial interactions in subterranean karst caves, which increased our understanding about USC and supported karst caves as a methane sink. IMPORTANCE Karst caves have recently been demonstrated to be a potential atmospheric methane sink, presumably due to consumption by methane-oxidizing bacteria. However, the sparse knowledge about the diversity, distribution, and community interactions of methanotrophs requires us to seek further understanding of the ecological significance of methane oxidation in these ecosystems. Our pmoA high-throughput results from weathered rock samples from three karst caves in Guilin City confirm the wide occurrence of atmospheric methane-oxidizing bacteria in this habitat, especially those affiliated with the upland soil cluster, with a gene copy number of 104 to 109 copies per gram dry sample. Methanotrophs and the total bacterial communities had more positive than negative interactions with each other as indicated by the cooccurrence network, suggesting their consistent response to environmental disturbance. Our results solidly support caves as an atmospheric methane sink, and they contribute to a comprehensive understanding of the diversity, distribution, and interactions of microbial communities in subsurface karst caves.
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Affiliation(s)
- Xiao-Yu Cheng
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Xiao-Yan Liu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Hong-Mei Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Chun-Tian Su
- Institute of Karst Geology, CAGS/Key Laboratory of Karst Dynamics, MNR & GZAR, Guilin, China
| | - Rui Zhao
- School of Marine Science and Policy, University of Delaware, Lewes, Delaware, USA
| | - Paul L. E. Bodelier
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
| | - Wei-Qi Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Li-Yuan Ma
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Xiao-Lu Lu
- School of Environmental Studies, China University of Geosciences, Wuhan, China
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24
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Yun J, Crombie AT, Ul Haque MF, Cai Y, Zheng X, Wang J, Jia Z, Murrell JC, Wang Y, Du W. Revealing the community and metabolic potential of active methanotrophs by targeted metagenomics in the Zoige wetland of the Tibetan Plateau. Environ Microbiol 2021; 23:6520-6535. [PMID: 34390603 DOI: 10.1111/1462-2920.15697] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 01/21/2023]
Abstract
The Zoige wetland of the Tibetan Plateau is one of the largest alpine wetlands in the world and a major emission source of methane. Methane oxidation by methanotrophs can counteract the global warming effect of methane released in the wetlands. Understanding methanotroph activity, diversity and metabolism at the molecular level can guide the isolation of the uncultured microorganisms and inform strategy-making decisions and policies to counteract global warming in this unique ecosystem. Here we applied DNA stable isotope probing using 13 C-labelled methane to label the genomes of active methanotrophs, examine the methane oxidation potential and recover metagenome-assembled genomes (MAGs) of active methanotrophs. We found that gammaproteobacteria of type I methanotrophs are responsible for methane oxidation in the wetland. We recovered two phylogenetically novel methanotroph MAGs distantly related to extant Methylobacter and Methylovulum. They belong to type I methanotrophs of gammaproteobacteria, contain both mxaF and xoxF types of methanol dehydrogenase coding genes, and participate in methane oxidation via H4 MPT and RuMP pathways. Overall, the community structure of active methanotrophs and their methanotrophic pathways revealed by DNA-SIP metagenomics and retrieved methanotroph MAGs highlight the importance of methanotrophs in suppressing methane emission in the wetland under the scenario of global warming.
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Affiliation(s)
- Juanli Yun
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Andrew T Crombie
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | | | - Yuanfeng Cai
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province, 210008, China
| | - Xiaowei Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jian Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province, 210008, China
| | - J Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Yanfen Wang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 10049, China.,CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenbin Du
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,Savaid Medical School, University of the Chinese Academy of Sciences, Beijing, 10049, China
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25
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Hakobyan A, Liesack W. Unexpected metabolic versatility among type II methanotrophs in the Alphaproteobacteria. Biol Chem 2021; 401:1469-1477. [PMID: 32769217 DOI: 10.1515/hsz-2020-0200] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/04/2020] [Indexed: 12/16/2022]
Abstract
Aerobic methane-oxidizing bacteria, or methanotrophs, play a crucial role in the global methane cycle. Their methane oxidation activity in various environmental settings has a great mitigation effect on global climate change. Alphaproteobacterial methanotrophs were among the first to be taxonomically characterized, nowadays unified in the Methylocystaceae and Beijerinckiaceae families. Originally thought to have an obligate growth requirement for methane and related one-carbon compounds as a source of carbon and energy, it was later shown that various alphaproteobacterial methanotrophs are facultative, able to grow on multi-carbon compounds such as acetate. Most recently, we expanded our knowledge of the metabolic versatility of alphaproteobacterial methanotrophs. We showed that Methylocystis sp. strain SC2 has the capacity for mixotrophic growth on H2 and CH4. This mini-review will summarize the change in perception from the long-held paradigm of obligate methanotrophy to today's recognition of alphaproteobacterial methanotrophs as having both facultative and mixotrophic capabilities.
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Affiliation(s)
- Anna Hakobyan
- Research group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, D-35043, Marburg, Germany
| | - Werner Liesack
- Research group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, D-35043, Marburg, Germany
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26
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Kox MAR, Smolders AJP, Speth DR, Lamers LPM, Op den Camp HJM, Jetten MSM, van Kessel MAHJ. A Novel Laboratory-Scale Mesocosm Setup to Study Methane Emission Mitigation by Sphagnum Mosses and Associated Methanotrophs. Front Microbiol 2021; 12:652486. [PMID: 33981290 PMCID: PMC8108401 DOI: 10.3389/fmicb.2021.651103] [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: 01/11/2021] [Accepted: 03/26/2021] [Indexed: 11/13/2022] Open
Abstract
Degraded peatlands are often rewetted to prevent oxidation of the peat, which reduces CO2 emission. However, the created anoxic conditions will boost methane (CH4) production and thus emission. Here, we show that submerged Sphagnum peat mosses in rewetted-submerged peatlands can reduce CH4 emission from peatlands with 93%. We were able to mimic the field situation in the laboratory by using a novel mesocosm set-up. By combining these with 16S rRNA gene amplicon sequencing and qPCR analysis of the pmoA and mmoX genes, we showed that submerged Sphagnum mosses act as a niche for CH4 oxidizing bacteria. The tight association between Sphagnum peat mosses and methane oxidizing bacteria (MOB) significantly reduces CH4 emissions by peatlands and can be studied in more detail in the mesocosm setup developed in this study.
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Affiliation(s)
- Martine A R Kox
- Department of Microbiology, IWWR, Radboud University, Nijmegen, Netherlands.,Department of Aquatic Ecology and Environmental Biology, IWWR, Radboud University, Nijmegen, Netherlands
| | - Alfons J P Smolders
- Department of Aquatic Ecology and Environmental Biology, IWWR, Radboud University, Nijmegen, Netherlands.,B-WARE Research Centre, Nijmegen, Netherlands
| | - Daan R Speth
- Department of Microbiology, IWWR, Radboud University, Nijmegen, Netherlands
| | - Leon P M Lamers
- Department of Aquatic Ecology and Environmental Biology, IWWR, Radboud University, Nijmegen, Netherlands
| | | | - Mike S M Jetten
- Department of Microbiology, IWWR, Radboud University, Nijmegen, Netherlands
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27
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Ma RC, Chu YX, Wang J, Wang C, Leigh MB, Chen Y, He R. Stable-isotopic and metagenomic analyses reveal metabolic and microbial link of aerobic methane oxidation coupled to denitrification at different O 2 levels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:142901. [PMID: 33757249 DOI: 10.1016/j.scitotenv.2020.142901] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 06/12/2023]
Abstract
Aerobic methane (CH4) oxidation coupled to denitrification (AME-D) can not only mitigate CH4 emission into the atmosphere, but also potentially alleviate nitrogen pollution in surface waters and engineered ecosystems, and it has attracted substantial research interest. O2 concentration plays a key role in AME-D, yet little is understood about how it impacts microbial interactions. Here, we applied isotopically labeled K15NO3 and 13CH4 and metagenomic analyses to investigate the metabolic and microbial link of AME-D at different O2 levels. Among the four experimental O2 levels of 21%,10%, 5% and 2.5% and a CH4 concentration of 8% (i.e., the O2/CH4 ratios of 2.62, 1.26, 0.63 and 0.31), the highest NO3--N removal occurred in the AME-D system incubated at the O2 concentration of 10%. Methanol and acetate may serve as the trophic linkage between aerobic methanotrophs and denitrifers in the AME-D systems. Methylotrophs including Methylophilus, Methylovorus, Methyloversatilis and Methylotenera were abundant under the O2-sufficient condition with the O2 concentration of 21%, while denitrifiers such as Azoarcus, Thauera and Thiobacillus dominated in the O2-limited environment with the O2 concentration of 10%. The competition of denitrifiers and methylotrophs in the AME-D system for CH4-derived carbon, such as methanol and acetate, might be influenced by chemotactic responses. More methane-derived carbon flowed into methylotrophs under the O2-sufficient condition, while more methane-derived carbon was used for denitrification in the O2-limited environment. These findings can aid in evaluating the distribution and contribution of AME-D and in developing strategies for mitigating CH4 emission and nitrogen pollution in natural and engineered ecosystems.
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Affiliation(s)
- Ruo-Chan Ma
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Yi-Xuan Chu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Jing Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Cheng Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Mary Beth Leigh
- Institute of Arctic Biology, University of Alaska Fairbanks, AK 99775, USA
| | - Yin Chen
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Ruo He
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
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28
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Wang J, Chu YX, Yao XZ, He R. Enhanced degradation of methanethiol in enrichment cultures in the presence of methane. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.107934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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29
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Abstract
Methanotrophic bacteria represent a potential route to methane utilization and mitigation of methane emissions. In the first step of their metabolic pathway, aerobic methanotrophs use methane monooxygenases (MMOs) to activate methane, oxidizing it to methanol. There are two types of MMOs: a particulate, membrane-bound enzyme (pMMO) and a soluble, cytoplasmic enzyme (sMMO). The two MMOs are completely unrelated, with different architectures, metal cofactors, and mechanisms. The more prevalent of the two, pMMO, is copper-dependent, but the identity of its copper active site remains unclear. By contrast, sMMO uses a diiron active site, the catalytic cycle of which is well understood. Here we review the current state of knowledge for both MMOs, with an emphasis on recent developments and emerging hypotheses. In addition, we discuss obstacles to developing expression systems, which are needed to address outstanding questions and to facilitate future protein engineering efforts.
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Affiliation(s)
- Christopher W Koo
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, IL 60208, USA.
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30
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Tveit AT, Kiss A, Winkel M, Horn F, Hájek T, Svenning MM, Wagner D, Liebner S. Environmental patterns of brown moss- and Sphagnum-associated microbial communities. Sci Rep 2020; 10:22412. [PMID: 33376244 PMCID: PMC7772339 DOI: 10.1038/s41598-020-79773-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 12/02/2020] [Indexed: 11/08/2022] Open
Abstract
Northern peatlands typically develop through succession from fens dominated by the moss family Amblystegiaceae to bogs dominated by the moss genus Sphagnum. How the different plants and abiotic environmental conditions provided in Amblystegiaceae and Sphagnum peat shape the respective moss associated microbial communities is unknown. Through a large-scale molecular and biogeochemical study spanning Arctic, sub-Arctic and temperate regions we assessed how the endo- and epiphytic microbial communities of natural northern peatland mosses relate to peatland type (Sphagnum and Amblystegiaceae), location, moss taxa and abiotic environmental variables. Microbial diversity and community structure were distinctly different between Amblystegiaceae and Sphagnum peatlands, and within each of these two peatland types moss taxon explained the largest part of microbial community variation. Sphagnum and Amblystegiaceae shared few (< 1% of all operational taxonomic units (OTUs)) but strikingly abundant (up to 65% of relative abundance) OTUs. This core community overlapped by one third with the Sphagnum-specific core-community. Thus, the most abundant microorganisms in Sphagnum that are also found in all the Sphagnum plants studied, are the same OTUs as those few shared with Amblystegiaceae. Finally, we could confirm that these highly abundant OTUs were endophytes in Sphagnum, but epiphytes on Amblystegiaceae. We conclude that moss taxa and abiotic environmental variables associate with particular microbial communities. While moss taxon was the most influential parameter, hydrology, pH and temperature also had significant effects on the microbial communities. A small though highly abundant core community is shared between Sphagnum and Amblystegiaceae.
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Affiliation(s)
- Alexander Tøsdal Tveit
- UiT The Arctic University of Norway, Department of Arctic and Marine Biology, Tromsø, Norway
| | - Andrea Kiss
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany
| | - Matthias Winkel
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany
| | - Fabian Horn
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany
| | - Tomáš Hájek
- University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic
| | - Mette Marianne Svenning
- UiT The Arctic University of Norway, Department of Arctic and Marine Biology, Tromsø, Norway
| | - Dirk Wagner
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany
- University of Potsdam, Institute of Geosciences, Potsdam, Germany
| | - Susanne Liebner
- GFZ German Research Center for Geosciences, Section Geomicrobiology, Potsdam, Germany.
- University of Potsdam, Institute of Biochemistry and Biology, Potsdam, Germany.
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31
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Mohanty SR, Kumar A, Parmar R, Dubey G, Patra A, Kollah B. Do methanotrophs drive phosphorus mineralization in soil ecosystem? Can J Microbiol 2020; 67:464-475. [PMID: 33301360 DOI: 10.1139/cjm-2020-0254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments were carried out to elucidate linkage between methane consumption and mineralization of phosphorous (P) from different P sources. The treatments were (i) no CH4 + no P amendment (absolute control), (ii) with CH4 + no P amendment (control), (iii) with CH4 + inorganic P as Ca3(PO4)2, and (iv) with CH4 + organic P as sodium phytate. P sources were added at 25 µg P·(g soil)-1. Soils were incubated to undergo three repeated CH4 feeding cycles, referred to as feeding cycle I, feeding cycle II, and feeding cycle III. CH4 consumption rate k (µg CH4 consumed·(g soil)-1·day-1) was 0.297 ± 0.028 in no P amendment control, 0.457 ± 0.016 in Ca3(PO4)2, and 0.627 ± 0.013 in sodium phytate. Rate k was stimulated by 2 to 6 times over CH4 feeding cycles and followed the trend of sodium phytate > Ca3(PO4)2 > no P amendment control. CH4 consumption stimulated P solubilization from Ca3(PO4)2 by a factor of 2.86. Acid phosphatase (µg paranitrophenol released·(g soil)-1·h-1) was higher in sodium phytate than the no P amendment control. Abundance of 16S rRNA and pmoA genes increased with CH4 consumption rates. The results of the study suggested that CH4 consumption drives mineralization of unavailable inorganic and organic P sources in the soil ecosystem.
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Affiliation(s)
- Santosh Ranjan Mohanty
- Indian Institute of Soil Science, Indian Council of Agricultural Research, Berasia Road, Nabibagh, Bhopal 462038, India
| | - Adarsh Kumar
- Indian Institute of Soil Science, Indian Council of Agricultural Research, Berasia Road, Nabibagh, Bhopal 462038, India.,National Bureau of Agriculturally Important Microorganisms, Indian Council of Agricultural Research, Kushmaur, Mau, Uttar Pradesh 275101, India
| | - Rakesh Parmar
- Indian Institute of Soil Science, Indian Council of Agricultural Research, Berasia Road, Nabibagh, Bhopal 462038, India
| | - Garima Dubey
- Indian Institute of Soil Science, Indian Council of Agricultural Research, Berasia Road, Nabibagh, Bhopal 462038, India
| | - Ashok Patra
- Indian Institute of Soil Science, Indian Council of Agricultural Research, Berasia Road, Nabibagh, Bhopal 462038, India
| | - Bharati Kollah
- Indian Institute of Soil Science, Indian Council of Agricultural Research, Berasia Road, Nabibagh, Bhopal 462038, India
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32
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Methane Monooxygenase Gene Transcripts as Quantitative Biomarkers of Methanotrophic Activity in Methylosinus trichosporium OB3b. Appl Environ Microbiol 2020; 86:AEM.01048-20. [PMID: 32948519 DOI: 10.1128/aem.01048-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/10/2020] [Indexed: 01/20/2023] Open
Abstract
Methanotrophic microorganisms are characterized by their ability to oxidize methane. Globally they have a significant impact on methane emissions by attenuating net methane fluxes to the atmosphere in natural and engineered systems, though the populations are dynamic in their activity level in soils and waters. Methanotrophs oxidize methane using methane monooxygenase (MMO) enzymes, and selected subunit genes of the most common MMOs, specifically pmoA and mmoX, are used as biomarkers for the presence and abundance of populations of bacterial methanotrophs. The relative expression of these biomarker genes is dependent on copper-to-biomass ratios. Empirically derived quantitative relationships between methane oxidation biomarker transcript amounts and methanotrophic activity could facilitate determination of methane oxidation rates. In this study, pure cultures of a model type II methanotroph, Methylosinus trichosporium OB3b, were grown in hollow-fiber membrane bioreactors (HFMBR) under different steady-state methane oxidation conditions. Methanotroph biomass (DNA based) and methane oxidation biomarker mRNA transcript amounts were determined using quantitative PCR (qPCR) and reverse transcription-PCR (RT-qPCR), respectively. Under both copper-present and copper-limited conditions, per-cell pmoA mRNA transcript levels positively correlated with measured per-cell methane oxidation rates across 3 orders of magnitude. These correlations, if maintained across different methanotrophs, could prove valuable for inferring in situ oxidation rates of methanotrophs and understanding the dynamics of their impact on net methane emissions.IMPORTANCE Methanotrophs are naturally occurring microorganisms capable of oxidizing methane and have an impact on global net methane emissions. The genes pmoA and mmoX are used as biomarkers for bacterial methanotrophs. Quantitative relationships between transcript amounts of these genes and methane oxidation rates could facilitate estimation of methanotrophic activity. In this study, a strong correlation was observed between per-cell pmoA transcript levels and per-cell methane oxidation rates for pure cultures of the aerobic methanotroph M. trichosporium OB3b grown in bioreactors. If similar relationships exist across different methanotrophs, they could prove valuable for inferring in situ oxidation rates of methanotrophs and better understanding their impact on net methane emissions.
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Cai Y, Zhou X, Shi L, Jia Z. Atmospheric Methane Oxidizers Are Dominated by Upland Soil Cluster Alpha in 20 Forest Soils of China. MICROBIAL ECOLOGY 2020; 80:859-871. [PMID: 32803363 DOI: 10.1007/s00248-020-01570-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 08/03/2020] [Indexed: 05/25/2023]
Abstract
Upland soil clusters alpha and gamma (USCα and USCγ) are considered a major biological sink of atmospheric methane and are often detected in forest and grassland soils. These clusters are phylogenetically classified using the particulate methane monooxygenase gene pmoA because of the difficulty of cultivation. Recent studies have established a direct link of pmoA genes to 16S rRNA genes based on their isolated strain or draft genomes. However, whether the results of pmoA-based assays could be largely represented by 16S rRNA gene sequencing in upland soils remains unclear. In this study, we collected 20 forest soils across China and compared methane-oxidizing bacterial (MOB) communities by high-throughput sequencing of 16S rRNA and pmoA genes using different primer sets. The results showed that 16S rRNA gene sequencing and the semi-nested polymerase chain reaction (PCR) of the pmoA gene (A189/A682r nested with a mixture of mb661 and A650) consistently revealed the dominance of USCα (accounting for more than 50% of the total MOB) in 12 forest soils. A189f/A682r successfully amplified pmoA genes (mainly RA14 of USCα) in only three forest soils. A189f/mb661 could amplify USCα (mainly JR1) in several forest soils but showed a strong preferential amplification of Methylocystis and many other type I MOB groups. A189f/A650 almost exclusively amplified USCα (mainly JR1) and largely discriminated against Methylocystis and most of the other MOB groups. The semi-nested PCR approach weakened the bias of A189f/mb661 and A189f/A650 for JR1 and balanced the coverage of all USCα members. The canonical correspondence analysis indicated that soil NH4+-N and pH were the main environmental factors affecting the MOB community of Chinese forest soils. The RA14 of the USCα group prefers to live in soils with low pH, low temperature, low elevation, high precipitation, and rich in nitrogen. JR1's preferences for temperature and elevation were opposite to RA14. Our study suggests that combining the deep sequencing of 16S rRNA and pmoA genes to characterize MOB in forest soils is the best choice.
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Affiliation(s)
- Yuanfeng Cai
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, China
| | - Xue Zhou
- College of agricultural science and engineering, Hohai University, Nanjing, 210098, Jiangsu Province, China
| | - Limei Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, China
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, China.
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Farhan Ul Haque M, Xu HJ, Murrell JC, Crombie A. Facultative methanotrophs - diversity, genetics, molecular ecology and biotechnological potential: a mini-review. MICROBIOLOGY (READING, ENGLAND) 2020; 166:894-908. [PMID: 33085587 PMCID: PMC7660913 DOI: 10.1099/mic.0.000977] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/20/2020] [Indexed: 12/18/2022]
Abstract
Methane-oxidizing bacteria (methanotrophs) play a vital role in reducing atmospheric methane emissions, and hence mitigating their potent global warming effects. A significant proportion of the methane released is thermogenic natural gas, containing associated short-chain alkanes as well as methane. It was one hundred years following the description of methanotrophs that facultative strains were discovered and validly described. These can use some multi-carbon compounds in addition to methane, often small organic acids, such as acetate, or ethanol, although Methylocella strains can also use short-chain alkanes, presumably deriving a competitive advantage from this metabolic versatility. Here, we review the diversity and molecular ecology of facultative methanotrophs. We discuss the genetic potential of the known strains and outline the consequent benefits they may obtain. Finally, we review the biotechnological promise of these fascinating microbes.
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Affiliation(s)
| | - Hui-Juan Xu
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: Joint Institute for Environmental Research & Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China
| | - J. Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andrew Crombie
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
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Lee MR, Oberle B, Olivas W, Young DF, Zanne AE. Wood construction more strongly shapes deadwood microbial communities than spatial location over 5 years of decay. Environ Microbiol 2020; 22:4702-4717. [PMID: 32840945 DOI: 10.1111/1462-2920.15212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 07/12/2020] [Accepted: 07/30/2020] [Indexed: 01/18/2023]
Abstract
Diverse communities of fungi and bacteria in deadwood mediate wood decay. While rates of decomposition vary greatly among woody species and spatially distinct habitats, the relative importance of these factors in structuring microbial communities and whether these shift over time remains largely unknown. We characterized fungal and bacterial diversity within pieces of deadwood that experienced 6.3-98.8% mass loss while decaying in common garden 'rotplots' in a temperate oak-hickory forest in the Ozark Highlands, MO, USA. Communities were isolated from 21 woody species that had been decomposing for 1-5 years in spatially distinct habitats at the landscape scale (top and bottom of watersheds) and within stems (top and bottom of stems). Microbial community structure varied more strongly with wood traits than with spatial locations, mirroring the relative role of these factors on decay rates on the same pieces of wood even after 5 years. Co-occurring fungal and bacterial communities persistently influenced one another independently from their shared environmental conditions. However, the relative influence of wood construction versus spatial locations differed between fungi and bacteria, suggesting that life history characteristics of these clades structure diversity differently across space and time in decomposing wood.
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Affiliation(s)
- Marissa R Lee
- Department of Plant and Microbial Biology, North Carolina State University, Campus Box 7612, Raleigh, NC, 27695, USA
| | - Brad Oberle
- Division of Natural Sciences, New College of Florida, 5800 Bay Shore Rd., Sarasota, FL, 34243, USA
| | - Wendy Olivas
- Department of Biology, University of Missouri, St Louis, MO, 63108, USA
| | - Darcy F Young
- Department of Biological Sciences, The George Washington University, 800 22nd St. NW Suite 6000, Washington, DC, 20052, USA
| | - Amy E Zanne
- Department of Biological Sciences, The George Washington University, 800 22nd St. NW Suite 6000, Washington, DC, 20052, USA
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Hördt A, López MG, Meier-Kolthoff JP, Schleuning M, Weinhold LM, Tindall BJ, Gronow S, Kyrpides NC, Woyke T, Göker M. Analysis of 1,000+ Type-Strain Genomes Substantially Improves Taxonomic Classification of Alphaproteobacteria. Front Microbiol 2020; 11:468. [PMID: 32373076 PMCID: PMC7179689 DOI: 10.3389/fmicb.2020.00468] [Citation(s) in RCA: 259] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 03/04/2020] [Indexed: 11/13/2022] Open
Abstract
The class Alphaproteobacteria is comprised of a diverse assemblage of Gram-negative bacteria that includes organisms of varying morphologies, physiologies and habitat preferences many of which are of clinical and ecological importance. Alphaproteobacteria classification has proved to be difficult, not least when taxonomic decisions rested heavily on a limited number of phenotypic features and interpretation of poorly resolved 16S rRNA gene trees. Despite progress in recent years regarding the classification of bacteria assigned to the class, there remains a need to further clarify taxonomic relationships. Here, draft genome sequences of a collection of genomes of more than 1000 Alphaproteobacteria and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa recognized as problematic long ago but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera and of a variety of genera to other families. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which are confirmed as valuable taxonomic markers. Similarly, analysis of the gene content was shown to provide valuable taxonomic insights in the class. Significant incongruities between 16S rRNA gene and whole genome trees were not found in the class. The incongruities that became obvious when comparing the results of the present study with existing classifications appeared to be caused mainly by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. Another probable cause of misclassifications in the past is the partially low overall fit of phenotypic characters to the sequence-based tree. Even though a significant degree of phylogenetic conservation was detected in all characters investigated, the overall fit to the tree varied considerably.
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Affiliation(s)
- Anton Hördt
- Department of Bioinformatics, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
| | - Marina García López
- Department of Bioinformatics, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
| | - Jan P. Meier-Kolthoff
- Department of Bioinformatics, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
| | - Marcel Schleuning
- Department of Bioinformatics, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
| | - Lisa-Maria Weinhold
- Department of Bioinformatics, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czechia
| | - Brian J. Tindall
- Department of Microorganisms, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
| | - Sabine Gronow
- Department of Microorganisms, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
| | - Nikos C. Kyrpides
- Department of Energy, Joint Genome Institute, Berkeley, CA, United States
| | - Tanja Woyke
- Department of Energy, Joint Genome Institute, Berkeley, CA, United States
| | - Markus Göker
- Department of Bioinformatics, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Brunswick, Germany
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Chu YX, Ma RC, Wang J, Zhu JT, Kang YR, He R. Effects of oxygen tension on the microbial community and functional gene expression of aerobic methane oxidation coupled to denitrification systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:12280-12292. [PMID: 31993906 DOI: 10.1007/s11356-020-07767-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
Aerobic CH4 oxidation coupled to denitrification (AME-D) can not only mitigate the emission of greenhouse gas (e.g., CH4) to the atmosphere, but also reduce NO3- and/or NO2- and alleviate nitrogen pollution. The effects of O2 tension on the community and functional gene expression of methanotrophs and denitrifiers were investigated in this study. Although higher CH4 oxidation occurred in the AME-D system with an initial O2 concentration of 21% (i.e., the O2-sufficient condition), more NO3--N was removed at the initial O2 concentration of 10% (i.e., the O2-limited environment). Type I methanotrophs, including Methylocaldum, Methylobacter, Methylococcus, Methylomonas, and Methylomicrobium, and type II methanotrophs, including Methylocystis and Methylosinus, dominated in the AME-D systems. Compared with type II methanotrophs, type I methanotrophs were more abundant in the AME-D systems. Proteobacteria and Actinobacteria were the main denitrifiers in the AME-D systems, and their compositions varied with the O2 tension. Quantitative PCR of the pmoA, nirS, and 16S rRNA genes showed that methanotrophs and denitrifiers were the main microorganisms in the AME-D systems, accounting for 46.4% and 24.1% in the O2-limited environment, respectively. However, the relative transcripts of the functional genes including pmoA, mmoX, nirK, nirS, and norZ were all less than 1%, especially the functional genes involved in denitrification under the O2-sufficient condition, likely due to the majority of the denitrifiers being dormant or even nonviable. These findings indicated that an optimal O2 concentration should be used to optimize the activity and functional gene expression of aerobic methanotrophs and denitrifiers in AME-D systems.
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Affiliation(s)
- Yi-Xuan Chu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo-Chan Ma
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jing Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jia-Tian Zhu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ya-Ru Kang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo He
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
- College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China.
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He R, Su Y, Leewis MC, Chu YX, Wang J, Ma RC, Wu D, Zhan LT, Herriott IC, Leigh MB. Low O 2 level enhances CH 4-derived carbon flow into microbial communities in landfill cover soils. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113676. [PMID: 31818614 DOI: 10.1016/j.envpol.2019.113676] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/07/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
Abstract
CH4 oxidation in landfill cover soils plays a significant role in mitigating CH4 release to the atmosphere. Oxygen availability and the presence of co-contaminants are potentially important factors affecting CH4 oxidation rate and the fate of CH4-derived carbon. In this study, microbial populations that oxidize CH4 and the subsequent conversion of CH4-derived carbon into CO2, soil organic C and biomass C were investigated in landfill cover soils at two O2 tensions, i.e., O2 concentrations of 21% ("sufficient") and 2.5% ("limited") with and without toluene. CH4-derived carbon was primarily converted into CO2 and soil organic C in the landfill cover soils, accounting for more than 80% of CH4 oxidized. Under the O2-sufficient condition, 52.9%-59.6% of CH4-derived carbon was converted into CO2 (CECO2-C), and 29.1%-39.3% was converted into soil organic C (CEorganic-C). A higher CEorganic-C and lower CECO2-C occurred in the O2-limited environment, relative to the O2-sufficient condition. With the addition of toluene, the carbon conversion efficiency of CH4 into biomass C and organic C increased slightly, especially in the O2-limited environment. A more complex microbial network was involved in CH4 assimilation in the O2-limited environment than under the O2-sufficient condition. DNA-based stable isotope probing of the community with 13CH4 revealed that Methylocaldum and Methylosarcina had a higher relative growth rate than other type I methanotrophs in the landfill cover soils, especially at the low O2 concentration, while Methylosinus was more abundant in the treatment with both the high O2 concentration and toluene. These results indicated that O2-limited environments could prompt more CH4-derived carbon to be deposited into soils in the form of biomass C and organic C, thereby enhancing the contribution of CH4-derived carbon to soil community biomass and functionality of landfill cover soils (i.e. reduction of CO2 emission).
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Affiliation(s)
- Ruo He
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China.
| | - Yao Su
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China; Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Mary-Cathrine Leewis
- Institute of Arctic Biology, University of Alaska Fairbanks, Alaska, 99775, USA; US Geological Survey, Menlo Park, CA, 94025, USA
| | - Yi-Xuan Chu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jing Wang
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Ruo-Chan Ma
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Donglei Wu
- Department of Environmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Liang-Tong Zhan
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou, 310058, China
| | | | - Mary Beth Leigh
- Institute of Arctic Biology, University of Alaska Fairbanks, Alaska, 99775, USA
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Islam T, Larsen Ø, Birkeland NK. A Novel Cold-adapted Methylovulum species, with a High C16:1ω5c Content, Isolated from an Arctic Thermal Spring in Spitsbergen. Microbes Environ 2020; 35:ME20044. [PMID: 32536671 PMCID: PMC7511782 DOI: 10.1264/jsme2.me20044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 04/25/2020] [Indexed: 11/12/2022] Open
Abstract
A novel cold-adapted methane-oxidizing bacterium, termed TFB, was isolated from the thermoglacial Arctic karst spring, Trollosen, located in the South Spitsbergen National Park (Norway). The source water is cold and extremely low in phosphate and nitrate. The isolate belongs to the Methylovulum genus of gammaproteobacterial methanotrophs, with the closest phylogenetic affiliation with Methylovulum miyakonense and Methylovulum psychrotolerans (96.2 and 96.1% 16S rRNA gene sequence similarities, respectively). TFB is a strict aerobe that only grows in the presence of methane or methanol. It fixes atmospheric nitrogen and contains Type I intracellular membranes. The growth temperature range was 2-22°C, with an optimum at 13-18°C. The functional genes pmoA, mxaF, and nifH were identified by PCR, whereas mmoX and cbbL were not. C16:1ω5c was identified as the major fatty acid constituent, at an amount (>49%) not previously found in any methanotrophs, and is likely to play a major role in cold adaptation. Strain TFB may be regarded as a new psychrotolerant or psychrophilic species within the genus Methylovulum. The recovery of this cold-adapted bacterium from a neutral Arctic thermal spring increases our knowledge of the diversity and adaptation of extremophilic gammaproteobacterial methanotrophs in the candidate family "Methylomonadaceae".
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Affiliation(s)
- Tajul Islam
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- Bergen Katedralskole, Kong Oscars gate 36, 5017 Bergen, Norway
| | - Øivind Larsen
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- NORCE Norwegian Research Centre AS, Bergen, Norway
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Noh HJ, Baek K, Hwang CY, Shin SC, Hong SG, Lee YM. Lichenihabitans psoromatis gen. nov., sp. nov., a member of a novel lineage ( Lichenihabitantaceae fam. nov.) within the order of Rhizobiales isolated from Antarctic lichen. Int J Syst Evol Microbiol 2019; 69:3837-3842. [PMID: 31556866 DOI: 10.1099/ijsem.0.003695] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two Gram-stain-negative, facultative anaerobic chemoheterotrophic, pink-coloured, rod-shaped and non-motile bacterial strains, PAMC 29128 and PAMC 29148T, were isolated from lichen. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strains PAMC 29128 and PAMC 29148T belong to lichen-associated Rhizobiales-1 (LAR1), an uncultured phylogenetic lineage of the order Rhizobiales and the most closely related genera were Methylocapsa (<93.9 %) and Methylosinus (<93.8 %). The results of phylogenomic and genomic relatedness analyses also showed that strains PAMC 29128 and PAMC 29148T were clearly distinguished from other species in the order Rhizobiales with average nucleotide identity values of <71.4 % and genome-to-genome distance values of <22.7 %. Genomic analysis revealed that strains PAMC 29128 and PAMC 29148T did not contain genes involved in atmospheric nitrogen fixation or utilization of carbon compounds such as methane and methanol. Strains PAMC 29128 and PAMC 29148T were able to utilize certain monosaccharides, disaccharides, sugar alcohols and other organic compounds as a sole carbon source. The major fatty acids (>10 %) were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 33.7-39.7 %), summed feature 3 (C16 : 1 ω7c and/or C 16:1 ω6c; 25.2-25.4 %) and C19 :0 cyclo ω8c (11.9-15.4 %). The major respiratory quinone was Q-10. The genomic DNA G+C contents of PAMC 29128 and PAMC 29148T were 63.0 and 63.1 mol%, respectively. Their distinct phylogenetic position and some physiological characteristics support the proposal of Lichenihabitans gen. nov., with the type species Lichenihabitans psoromatis sp. nov. (type strain, PAMC 29148T=KCCM 43293T=JCM 33311T). Lichenihabitantaceae fam. nov. is also proposed.
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Affiliation(s)
- Hyun-Ju Noh
- Department of Biological Sciences, Inha University, Inharo 100, Incheon 22212, Republic of Korea
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Kiwoon Baek
- Bioresources Collection & Research Division, Nakdonggang National Institute of Biological Resources, 137 Donam 2-gil, Sangju 37242, Republic of Korea
- Department of Biological Sciences, Inha University, Inharo 100, Incheon 22212, Republic of Korea
| | - Chung Yeon Hwang
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Seung Chul Shin
- Unit of Polar Genomics, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Soon Gyu Hong
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Yung Mi Lee
- Division of Polar Life Sciences, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
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Lanthanide-Dependent Methylotrophs of the Family Beijerinckiaceae: Physiological and Genomic Insights. Appl Environ Microbiol 2019; 86:AEM.01830-19. [PMID: 31604774 DOI: 10.1128/aem.01830-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/07/2019] [Indexed: 01/07/2023] Open
Abstract
Methylotrophic bacteria use methanol and related C1 compounds as carbon and energy sources. Methanol dehydrogenases are essential for methanol oxidation, while lanthanides are important cofactors of many pyrroloquinoline quinone-dependent methanol dehydrogenases and related alcohol dehydrogenases. We describe here the physiological and genomic characterization of newly isolated Beijerinckiaceae bacteria that rely on lanthanides for methanol oxidation. A broad physiological diversity was indicated by the ability to metabolize a wide range of multicarbon substrates, including various sugars, and organic acids, as well as diverse C1 substrates such as methylated amines and methylated sulfur compounds. Methanol oxidation was possible only in the presence of low-mass lanthanides (La, Ce, and Nd) at submicromolar concentrations (>100 nM). In a comparison with other Beijerinckiaceae, genomic and transcriptomic analyses revealed the usage of a glutathione- and tetrahydrofolate-dependent pathway for formaldehyde oxidation and channeling methyl groups into the serine cycle for carbon assimilation. Besides a single xoxF gene, we identified two additional genes for lanthanide-dependent alcohol dehydrogenases, including one coding for an ExaF-type alcohol dehydrogenase, which was so far not known in Beijerinckiaceae Homologs for most of the gene products of the recently postulated gene cluster linked to lanthanide utilization and transport could be detected, but for now it remains unanswered how lanthanides are sensed and taken up by our strains. Studying physiological responses to lanthanides under nonmethylotrophic conditions in these isolates as well as other organisms is necessary to gain a more complete understanding of lanthanide-dependent metabolism as a whole.IMPORTANCE We supplemented knowledge of the broad metabolic diversity of the Beijerinckiaceae by characterizing new members of this family that rely on lanthanides for methanol oxidation and that possess additional lanthanide-dependent enzymes. Considering that lanthanides are critical resources for many modern applications and that recovering them is expensive and puts a heavy burden on the environment, lanthanide-dependent metabolism in microorganisms is an exploding field of research. Further research into how isolated Beijerinckiaceae and other microbes utilize lanthanides is needed to increase our understanding of lanthanide-dependent metabolism. The diversity and widespread occurrence of lanthanide-dependent enzymes make it likely that lanthanide utilization varies in different taxonomic groups and is dependent on the habitat of the microbes.
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Goh KM, Shahar S, Chan KG, Chong CS, Amran SI, Sani MH, Zakaria II, Kahar UM. Current Status and Potential Applications of Underexplored Prokaryotes. Microorganisms 2019; 7:E468. [PMID: 31635256 PMCID: PMC6843859 DOI: 10.3390/microorganisms7100468] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/05/2019] [Accepted: 10/08/2019] [Indexed: 12/20/2022] Open
Abstract
Thousands of prokaryotic genera have been published, but methodological bias in the study of prokaryotes is noted. Prokaryotes that are relatively easy to isolate have been well-studied from multiple aspects. Massive quantities of experimental findings and knowledge generated from the well-known prokaryotic strains are inundating scientific publications. However, researchers may neglect or pay little attention to the uncommon prokaryotes and hard-to-cultivate microorganisms. In this review, we provide a systematic update on the discovery of underexplored culturable and unculturable prokaryotes and discuss the insights accumulated from various research efforts. Examining these neglected prokaryotes may elucidate their novelties and functions and pave the way for their industrial applications. In addition, we hope that this review will prompt the scientific community to reconsider these untapped pragmatic resources.
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Affiliation(s)
- Kian Mau Goh
- Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia.
| | - Saleha Shahar
- Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia.
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia.
- International Genome Centre, Jiangsu University, ZhenJiang 212013, China.
| | - Chun Shiong Chong
- Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia.
| | - Syazwani Itri Amran
- Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia.
| | - Mohd Helmi Sani
- Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia.
| | - Iffah Izzati Zakaria
- Malaysia Genome Institute, National Institutes of Biotechnology Malaysia, Jalan Bangi, Kajang 43000, Selangor, Malaysia.
| | - Ummirul Mukminin Kahar
- Malaysia Genome Institute, National Institutes of Biotechnology Malaysia, Jalan Bangi, Kajang 43000, Selangor, Malaysia.
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Crevecoeur S, Ruiz-González C, Prairie YT, Del Giorgio PA. Large-scale biogeography and environmental regulation of methanotrophic bacteria across boreal inland waters. Mol Ecol 2019; 28:4181-4196. [PMID: 31479544 DOI: 10.1111/mec.15223] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/01/2019] [Accepted: 08/06/2019] [Indexed: 01/09/2023]
Abstract
Aerobic methanotrophic bacteria (methanotrophs) use methane as a source of carbon and energy, thereby mitigating net methane emissions from natural sources. Methanotrophs represent a widespread and phylogenetically complex guild, yet the biogeography of this functional group and the factors that explain the taxonomic structure of the methanotrophic assemblage are still poorly understood. Here, we used high-throughput sequencing of the 16S rRNA gene of the bacterial community to study the methanotrophic community composition and the environmental factors that influence their distribution and relative abundance in a wide range of freshwater habitats, including lakes, streams and rivers across the boreal landscape. Within one region, soil and soil water samples were additionally taken from the surrounding watersheds in order to cover the full terrestrial-aquatic continuum. The composition of methanotrophic communities across the boreal landscape showed only a modest degree of regional differentiation but a strong structuring along the hydrologic continuum from soil to lake communities, regardless of regions. This pattern along the hydrologic continuum was mostly explained by a clear niche differentiation between type I and type II methanotrophs along environmental gradients in pH, and methane concentrations. Our results suggest very different roles of type I and type II methanotrophs within inland waters, the latter likely having a terrestrial source and reflecting passive transport and dilution along the aquatic networks, but this is an unresolved issue that requires further investigation.
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Affiliation(s)
- Sophie Crevecoeur
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada
| | - Clara Ruiz-González
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada
| | - Paul A Del Giorgio
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique (GRIL), Université du Québec à Montréal, Montréal, QC, Canada
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Whiddon KT, Gudneppanavar R, Hammer TJ, West DA, Konopka MC. Fluorescence-based analysis of the intracytoplasmic membranes of type I methanotrophs. Microb Biotechnol 2019; 12:1024-1033. [PMID: 31264365 PMCID: PMC6680624 DOI: 10.1111/1751-7915.13458] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/16/2019] [Indexed: 12/15/2022] Open
Abstract
Most methanotrophic bacteria maintain intracytoplasmic membranes which house the methane-oxidizing enzyme, particulate methane monooxygenase. Previous studies have primarily used transmission electron microscopy or cryo-electron microscopy to look at the structure of these membranes or lipid extraction methods to determine the per cent of cell dry weight composed of lipids. We show an alternative approach using lipophilic membrane probes and other fluorescent dyes to assess the extent of intracytoplasmic membrane formation in living cells. This fluorescence method is sensitive enough to show not only the characteristic shift in intracytoplasmic membrane formation that is present when methanotrophs are grown with or without copper, but also differences in intracytoplasmic membrane levels at intermediate copper concentrations. This technique can also be employed to monitor dynamic intracytoplasmic membrane changes in the same cell in real time under changing growth conditions. We anticipate that this approach will be of use to researchers wishing to visualize intracytoplasmic membranes who may not have access to electron microscopes. It will also have the capability to relate membrane changes in individual living cells to other measurements by fluorescence labelling or other single-cell analysis methods.
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Affiliation(s)
| | | | - Theodore J. Hammer
- Department of ChemistryThe University of AkronAkronOHUSA
- Department of Polymer ScienceThe University of AkronAkronOHUSA
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Atmospheric carbon monoxide oxidation is a widespread mechanism supporting microbial survival. ISME JOURNAL 2019; 13:2868-2881. [PMID: 31358912 PMCID: PMC6794299 DOI: 10.1038/s41396-019-0479-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/22/2019] [Accepted: 06/28/2019] [Indexed: 11/09/2022]
Abstract
Carbon monoxide (CO) is a ubiquitous atmospheric trace gas produced by natural and anthropogenic sources. Some aerobic bacteria can oxidize atmospheric CO and, collectively, they account for the net loss of ~250 teragrams of CO from the atmosphere each year. However, the physiological role, genetic basis, and ecological distribution of this process remain incompletely resolved. In this work, we addressed these knowledge gaps through culture-based and culture-independent work. We confirmed through shotgun proteomic and transcriptional analysis that the genetically tractable aerobic soil actinobacterium Mycobacterium smegmatis upregulates expression of a form I molydenum-copper carbon monoxide dehydrogenase by 50-fold when exhausted for organic carbon substrates. Whole-cell biochemical assays in wild-type and mutant backgrounds confirmed that this organism aerobically respires CO, including at sub-atmospheric concentrations, using the enzyme. Contrary to current paradigms on CO oxidation, the enzyme did not support chemolithoautotrophic growth and was dispensable for CO detoxification. However, it significantly enhanced long-term survival, suggesting that atmospheric CO serves a supplemental energy source during organic carbon starvation. Phylogenetic analysis indicated that atmospheric CO oxidation is widespread and an ancestral trait of CO dehydrogenases. Homologous enzymes are encoded by 685 sequenced species of bacteria and archaea, including from seven dominant soil phyla, and we confirmed genes encoding this enzyme are abundant and expressed in terrestrial and marine environments. On this basis, we propose a new survival-centric model for the evolution of aerobic CO oxidation and conclude that, like atmospheric H2, atmospheric CO is a major energy source supporting persistence of aerobic heterotrophic bacteria in deprived or changeable environments.
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Ghashghavi M, Belova SE, Bodelier PLE, Dedysh SN, Kox MAR, Speth DR, Frenzel P, Jetten MSM, Lücker S, Lüke C. Methylotetracoccus oryzae Strain C50C1 Is a Novel Type Ib Gammaproteobacterial Methanotroph Adapted to Freshwater Environments. mSphere 2019; 4:e00631-18. [PMID: 31167950 PMCID: PMC6553558 DOI: 10.1128/msphere.00631-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 05/09/2019] [Indexed: 01/08/2023] Open
Abstract
Methane-oxidizing microorganisms perform an important role in reducing emissions of the greenhouse gas methane to the atmosphere. To date, known bacterial methanotrophs belong to the Proteobacteria, Verrucomicrobia, and NC10 phyla. Within the Proteobacteria phylum, they can be divided into type Ia, type Ib, and type II methanotrophs. Type Ia and type II are well represented by isolates. Contrastingly, the vast majority of type Ib methanotrophs have not been able to be cultivated so far. Here, we compared the distributions of type Ib lineages in different environments. Whereas the cultivated type Ib methanotrophs (Methylococcus and Methylocaldum) are found in landfill and upland soils, lineages that are not represented by isolates are mostly dominant in freshwater environments, such as paddy fields and lake sediments. Thus, we observed a clear niche differentiation within type Ib methanotrophs. Our subsequent isolation attempts resulted in obtaining a pure culture of a novel type Ib methanotroph, tentatively named "Methylotetracoccus oryzae" C50C1. Strain C50C1 was further characterized to be an obligate methanotroph, containing C16:1ω9c as the major membrane phospholipid fatty acid, which has not been found in other methanotrophs. Genome analysis of strain C50C1 showed the presence of two pmoCAB operon copies and XoxF5-type methanol dehydrogenase in addition to MxaFI. The genome also contained genes involved in nitrogen and sulfur cycling, but it remains to be demonstrated if and how these help this type Ib methanotroph to adapt to fluctuating environmental conditions in freshwater ecosystems.IMPORTANCE Most of the methane produced on our planet gets naturally oxidized by a group of methanotrophic microorganisms before it reaches the atmosphere. These microorganisms are able to oxidize methane, both aerobically and anaerobically, and use it as their sole energy source. Although methanotrophs have been studied for more than a century, there are still many unknown and uncultivated groups prevalent in various ecosystems. This study focused on the diversity and adaptation of aerobic methane-oxidizing bacteria in different environments by comparing their phenotypic and genotypic properties. We used lab-scale microcosms to create a countergradient of oxygen and methane for preenrichment, followed by classical isolation techniques to obtain methane-oxidizing bacteria from a freshwater environment. This resulted in the discovery and isolation of a novel methanotroph with interesting physiological and genomic properties that could possibly make this bacterium able to cope with fluctuating environmental conditions.
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Affiliation(s)
- Mohammad Ghashghavi
- Department of Microbiology, IWWR, Radboud University, Nijmegen, the Netherlands
| | - Svetlana E Belova
- Research Center of Biotechnology of the Russian Academy of Sciences, Winogradski Institute of Microbiology, Moscow, Russia
| | - Paul L E Bodelier
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands
| | - Svetlana N Dedysh
- Research Center of Biotechnology of the Russian Academy of Sciences, Winogradski Institute of Microbiology, Moscow, Russia
| | - Martine A R Kox
- Department of Microbiology, IWWR, Radboud University, Nijmegen, the Netherlands
| | - Daan R Speth
- Department of Microbiology, IWWR, Radboud University, Nijmegen, the Netherlands
| | - Peter Frenzel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Mike S M Jetten
- Department of Microbiology, IWWR, Radboud University, Nijmegen, the Netherlands
- Department of Biotechnology, Delft University of Technology, Delft, the Netherlands
- Soehngen Institute of Anaerobic Microbiology, Nijmegen, the Netherlands
| | - Sebastian Lücker
- Department of Microbiology, IWWR, Radboud University, Nijmegen, the Netherlands
| | - Claudia Lüke
- Department of Microbiology, IWWR, Radboud University, Nijmegen, the Netherlands
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Tveit AT, Hestnes AG, Robinson SL, Schintlmeister A, Dedysh SN, Jehmlich N, von Bergen M, Herbold C, Wagner M, Richter A, Svenning MM. Widespread soil bacterium that oxidizes atmospheric methane. Proc Natl Acad Sci U S A 2019; 116:8515-8524. [PMID: 30962365 PMCID: PMC6486757 DOI: 10.1073/pnas.1817812116] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The global atmospheric level of methane (CH4), the second most important greenhouse gas, is currently increasing by ∼10 million tons per year. Microbial oxidation in unsaturated soils is the only known biological process that removes CH4 from the atmosphere, but so far, bacteria that can grow on atmospheric CH4 have eluded all cultivation efforts. In this study, we have isolated a pure culture of a bacterium, strain MG08 that grows on air at atmospheric concentrations of CH4 [1.86 parts per million volume (p.p.m.v.)]. This organism, named Methylocapsa gorgona, is globally distributed in soils and closely related to uncultured members of the upland soil cluster α. CH4 oxidation experiments and 13C-single cell isotope analyses demonstrated that it oxidizes atmospheric CH4 aerobically and assimilates carbon from both CH4 and CO2 Its estimated specific affinity for CH4 (a0s) is the highest for any cultivated methanotroph. However, growth on ambient air was also confirmed for Methylocapsa acidiphila and Methylocapsa aurea, close relatives with a lower specific affinity for CH4, suggesting that the ability to utilize atmospheric CH4 for growth is more widespread than previously believed. The closed genome of M. gorgona MG08 encodes a single particulate methane monooxygenase, the serine cycle for assimilation of carbon from CH4 and CO2, and CO2 fixation via the recently postulated reductive glycine pathway. It also fixes dinitrogen and expresses the genes for a high-affinity hydrogenase and carbon monoxide dehydrogenase, suggesting that atmospheric CH4 oxidizers harvest additional energy from oxidation of the atmospheric trace gases carbon monoxide (0.2 p.p.m.v.) and hydrogen (0.5 p.p.m.v.).
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Affiliation(s)
- Alexander T Tveit
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsoe, Norway
| | - Anne Grethe Hestnes
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsoe, Norway
| | - Serina L Robinson
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsoe, Norway
| | - Arno Schintlmeister
- Center of Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Svetlana N Dedysh
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of Russian Academy of Sciences, 117312 Moscow, Russia
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research-UFZ, 04318 Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research-UFZ, 04318 Leipzig, Germany
- Faculty of Life Sciences, Institute of Biochemistry, University of Leipzig, 04109 Leipzig, Germany
| | - Craig Herbold
- Center of Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Michael Wagner
- Center of Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna, 1090 Vienna, Austria
| | - Andreas Richter
- Center of Microbiology and Environmental Systems Science, Division of Terrestrial Ecosystem Research, University of Vienna, 1090 Vienna, Austria
| | - Mette M Svenning
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, 9037 Tromsoe, Norway;
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48
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Shao Y, Hatzinger PB, Streger SH, Rezes RT, Chu KH. Evaluation of methanotrophic bacterial communities capable of biodegrading trichloroethene (TCE) in acidic aquifers. Biodegradation 2019; 30:173-190. [DOI: 10.1007/s10532-019-09875-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 04/04/2019] [Indexed: 10/27/2022]
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Mateos-Rivera A, Øvreås L, Wilson B, Yde JC, Finster KW. Activity and diversity of methane-oxidizing bacteria along a Norwegian sub-Arctic glacier forefield. FEMS Microbiol Ecol 2019; 94:4956520. [PMID: 29617984 DOI: 10.1093/femsec/fiy059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 03/28/2018] [Indexed: 11/14/2022] Open
Abstract
Methane (CH4) is one of the most abundant greenhouse gases in the atmosphere and identification of its sources and sinks is crucial for the reliability of climate model outputs. Although CH4 production and consumption rates have been reported from a broad spectrum of environments, data obtained from glacier forefields are restricted to a few locations. We report the activities of methanotrophic communities and their diversity along a chronosequence in front of a sub-Arctic glacier using high-throughput sequencing and gas flux measurements. CH4 oxidation rates were measured in the field throughout the growing season during three sampling times at eight different sampling points in combination with laboratory incubation experiments. The overall results showed that the methanotrophic community had similar trends of increased CH4 consumption and increased abundance as a function of soil development and time of year. Sequencing results revealed that the methanotrophic community was dominated by a few OTUs and that a short-term increase in CH4 concentration, as performed in the field measurements, altered slightly the relative abundance of the OTUs.
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Affiliation(s)
- Alejandro Mateos-Rivera
- Department of Biology, University of Bergen, NO-5020, Bergen, Norway.,Faculty of Engineering and Science, Western Norway University of Applied Sciences, NO-6851, Sogndal, Norway
| | - Lise Øvreås
- Department of Biology, University of Bergen, NO-5020, Bergen, Norway.,University Centre in Svalbard, NO-9171, Longyearbyen, Norway
| | - Bryan Wilson
- Department of Biology, University of Bergen, NO-5020, Bergen, Norway
| | - Jacob C Yde
- Faculty of Engineering and Science, Western Norway University of Applied Sciences, NO-6851, Sogndal, Norway
| | - Kai W Finster
- Department of Bioscience, Aarhus University, DK-8000, Aarhus, Denmark.,Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus, Denmark
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50
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Biodiversity of methylotrophic microbial communities and their potential role in mitigation of abiotic stresses in plants. Biologia (Bratisl) 2019. [DOI: 10.2478/s11756-019-00190-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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