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Sumner DY. Oxygenation of Earth's atmosphere induced metabolic and ecologic transformations recorded in the Lomagundi-Jatuli carbon isotopic excursion. Appl Environ Microbiol 2024; 90:e0009324. [PMID: 38819147 PMCID: PMC11218651 DOI: 10.1128/aem.00093-24] [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: 01/16/2024] [Accepted: 05/03/2024] [Indexed: 06/01/2024] Open
Abstract
The oxygenation of Earth's atmosphere represents the quintessential transformation of a planetary surface by microbial processes. In turn, atmospheric oxygenation transformed metabolic evolution; molecular clock models indicate the diversification and ecological expansion of respiratory metabolisms in the several hundred million years following atmospheric oxygenation. Across this same interval, the geological record preserves 13C enrichment in some carbonate rocks, called the Lomagundi-Jatuli excursion (LJE). By combining data from geologic and genomic records, a self-consistent metabolic evolution model emerges for the LJE. First, fermentation and methanogenesis were major processes remineralizing organic carbon before atmospheric oxygenation. Once an ozone layer formed, shallow water and exposed environments were shielded from UVB/C radiation, allowing the expansion of cyanobacterial primary productivity. High primary productivity and methanogenesis led to preferential removal of 12C into organic carbon and CH4. Extreme and variable 13C enrichments in carbonates were caused by 13C-depleted CH4 loss to the atmosphere. Through time, aerobic respiration diversified and became ecologically widespread, as did other new metabolisms. Respiration displaced fermentation and methanogenesis as the dominant organic matter remineralization processes. As CH4 loss slowed, dissolved inorganic carbon in shallow environments was no longer highly 13C enriched. Thus, the loss of extreme 13C enrichments in carbonates marks the establishment of a new microbial mat ecosystem structure, one dominated by respiratory processes distributed along steep redox gradients. These gradients allowed the exchange of metabolic by-products among metabolically diverse organisms, providing novel metabolic opportunities. Thus, the microbially induced oxygenation of Earth's atmosphere led to the transformation of microbial ecosystems, an archetypal example of planetary microbiology.IMPORTANCEThe oxygenation of Earth's atmosphere represents the most extensive known chemical transformation of a planetary surface by microbial processes. In turn, atmospheric oxygenation transformed metabolic evolution by providing oxidants independent of the sites of photosynthesis. Thus, the evolutionary changes during this interval and their effects on planetary-scale biogeochemical cycles are fundamental to our understanding of the interdependencies among genomes, organisms, ecosystems, elemental cycles, and Earth's surface chemistry through time.
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Affiliation(s)
- Dawn Y. Sumner
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, USA
- Microbiology Graduate Group, University of California, Davis, Davis, California, USA
- Feminist Research Institute, University of California, Davis, Davis, California, USA
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2
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Zou C, Yi X, Li H, Bizic M, Berman-Frank I, Gao K. Correlation of methane production with physiological traits in Trichodesmium IMS 101 grown with methylphosphonate at different temperatures. Front Microbiol 2024; 15:1396369. [PMID: 38894967 PMCID: PMC11184136 DOI: 10.3389/fmicb.2024.1396369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
The diazotrophic cyanobacterium Trichodesmium has been recognized as a potentially significant contributor to aerobic methane generation via several mechanisms including the utilization of methylphophonate (MPn) as a source of phosphorus. Currently, there is no information about how environmental factors regulate methane production by Trichodesmium. Here, we grew Trichodesmium IMS101 at five temperatures ranging from 16 to 31°C, and found that its methane production rates increased with rising temperatures to peak (1.028 ± 0.040 nmol CH4 μmol POC-1 day-1) at 27°C, and then declined. Its specific growth rate changed from 0.03 ± 0.01 d-1 to 0.34 ± 0.02 d-1, with the optimal growth temperature identified between 27 and 31°C. Within the tested temperature range the Q10 for the methane production rate was 4.6 ± 0.7, indicating a high sensitivity to thermal changes. In parallel, the methane production rates showed robust positive correlations with the assimilation rates of carbon, nitrogen, and phosphorus, resulting in the methane production quotients (molar ratio of carbon, nitrogen, or phosphorus assimilated to methane produced) of 227-494 for carbon, 40-128 for nitrogen, and 1.8-3.4 for phosphorus within the tested temperature range. Based on the experimental data, we estimated that the methane released from Trichodesmium can offset about 1% of its CO2 mitigation effects.
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Affiliation(s)
- Chuze Zou
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Xiangqi Yi
- Polar and Marine Research Institute, College of Harbor and Coastal Engineering, Jimei University, Xiamen, China
| | - He Li
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Mina Bizic
- Department of Environmental Microbiomics, Institute of Environmental Technology, Technical University of Berlin, Berlin, Germany
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Ilana Berman-Frank
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, Xiamen, China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
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3
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Gao Z, Zheng Y, Li Z, Ruan A. Effects of 17β-Estradiol Pollution on Microbial Communities and Methane Emissions in Aerobic Water Bodies. TOXICS 2024; 12:373. [PMID: 38787152 PMCID: PMC11126138 DOI: 10.3390/toxics12050373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024]
Abstract
17β-Estradiol (E2) is a widely present trace pollutant in aquatic environments. However, its impact on microbial communities in aerobic lake waters, which are crucial for methane (CH4) production, remains unclear. This study conducted an E2 contamination experiment by constructing laboratory-simulated aerobic microecosystems. Using 16S rRNA high-throughput sequencing, the effects of E2 on bacterial and archaeal communities were systematically examined. Combined with gas chromatography, the patterns and mechanisms of E2's impact on CH4 emissions in aerobic aquatic systems were uncovered for the first time. Generally, E2 contamination increased the randomness of bacterial and archaeal community assemblies and weakened microbial interactions. Furthermore, changes occurred in the composition and ecological functions of bacterial and archaeal communities under E2 pollution. Specifically, two days after exposure to E2, the relative abundance of Proteobacteria in the low-concentration (L) and high-concentration (H) groups decreased by 6.99% and 4.01%, respectively, compared to the control group (C). Conversely, the relative abundance of Planctomycetota was 1.81% and 1.60% higher in the L and H groups, respectively. E2 contamination led to an increase in the relative abundance of the methanogenesis functional group and a decrease in that of the methanotrophy functional group. These changes led to an increase in CH4 emissions. This study comprehensively investigated the ecotoxicological effects of E2 pollution on microbial communities in aerobic water bodies and filled the knowledge gap regarding aerobic methane production under E2 contamination.
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Affiliation(s)
- Zihao Gao
- The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China; (Z.G.); (Y.Z.); (Z.L.)
- College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
| | - Yu Zheng
- The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China; (Z.G.); (Y.Z.); (Z.L.)
- College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
| | - Zhendong Li
- The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China; (Z.G.); (Y.Z.); (Z.L.)
- College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
| | - Aidong Ruan
- The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China; (Z.G.); (Y.Z.); (Z.L.)
- College of Geography and Remote Sensing, Hohai University, Nanjing 210098, China
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4
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Kang M, Liu L, Grossart HP. Spatio-temporal variations of methane fluxes in sediments of a deep stratified temperate lake. iScience 2024; 27:109520. [PMID: 38591008 PMCID: PMC11000008 DOI: 10.1016/j.isci.2024.109520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/09/2023] [Accepted: 03/14/2024] [Indexed: 04/10/2024] Open
Abstract
Spatio-temporal variability of sediment-mediated methane (CH4) production in freshwater lakes causes large uncertainties in predicting global lake CH4 emissions under different climate change and eutrophication scenarios. We conducted extensive sediment incubation experiments to investigate CH4 fluxes in Lake Stechlin, a deep, stratified temperate lake. Our results show contrasting spatial patterns in CH4 fluxes between littoral and profundal sites. The littoral sediments, ∼33% of the total sediment surface area, contributed ∼86.9% of the annual CH4 flux at the sediment-water interface. Together with sediment organic carbon quality, seasonal stratification is responsible for the striking spatial difference in sediment CH4 production between littoral and profundal zones owing to more sensitive CH4 production than oxidation to warming. While profundal sediments produce a relatively small amount of CH4, its production increases markedly as anoxia spreads in late summer. Our measurements indicate that future lake CH4 emissions will increase due to climate warming and concomitant hypoxia/anoxia.
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Affiliation(s)
- Manchun Kang
- Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Yichang 443002, China
- Hubei Field Observation and Scientific Research Stations for Water Ecosystem in Three Gorges Reservoir, Yichang 443002, China
| | - Liu Liu
- Yunnan Key Laboratory of Plateau Geographical Processes and Environmental Changes, Faculty of Geography, Yunnan Normal University, Kunming 650500, China
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Stechlin, Germany
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Stechlin, Germany
- Institute of Biochemistry and Biology, Potsdam University, 14476 Potsdam, Germany
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Kleikamp HBC, Palacios PA, Kofoed MVW, Papacharalampos G, Bentien A, Nielsen JL. The Selenoproteome as a Dynamic Response Mechanism to Oxidative Stress in Hydrogenotrophic Methanogenic Communities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6637-6646. [PMID: 38580315 PMCID: PMC11025550 DOI: 10.1021/acs.est.3c07725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 03/08/2024] [Accepted: 03/08/2024] [Indexed: 04/07/2024]
Abstract
Methanogenesis is a critical process in the carbon cycle that is applied industrially in anaerobic digestion and biogas production. While naturally occurring in diverse environments, methanogenesis requires anaerobic and reduced conditions, although varying degrees of oxygen tolerance have been described. Microaeration is suggested as the next step to increase methane production and improve hydrolysis in digestion processes; therefore, a deeper understanding of the methanogenic response to oxygen stress is needed. To explore the drivers of oxygen tolerance in methanogenesis, two parallel enrichments were performed under the addition of H2/CO2 in an environment without reducing agents and in a redox-buffered environment by adding redox mediator 9,10-anthraquinone-2,7-disulfonate disodium. The cellular response to oxidative conditions is mapped using proteomic analysis. The resulting community showed remarkable tolerance to high-redox environments and was unperturbed in its methane production. Next to the expression of pathways to mitigate reactive oxygen species, the higher redox potential environment showed an increased presence of selenocysteine and selenium-associated pathways. By including sulfur-to-selenium mass shifts in a proteomic database search, we provide the first evidence of the dynamic and large-scale incorporation of selenocysteine as a response to oxidative stress in hydrogenotrophic methanogenesis and the presence of a dynamic selenoproteome.
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Affiliation(s)
- Hugo B. C. Kleikamp
- Department
of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Paola A. Palacios
- Department
of Biological and Chemical Engineering, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | - Michael V. W. Kofoed
- Department
of Biological and Chemical Engineering, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | - Georgios Papacharalampos
- Department
of Biological and Chemical Engineering, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | - Anders Bentien
- Department
of Biological and Chemical Engineering, Aarhus University, Åbogade 40, 8200 Aarhus, Denmark
| | - Jeppe L. Nielsen
- Department
of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
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6
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Ma S, Yang M, Chen X, Wang F, Xia Y, Xu P, Ma J, Luo C, Zhou C, Xu T, Zhu Y. Microbial methanogenesis in aerobic water: A key driver of surface methane enrichment in a deep reservoir. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 355:120481. [PMID: 38447515 DOI: 10.1016/j.jenvman.2024.120481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/07/2024] [Accepted: 02/20/2024] [Indexed: 03/08/2024]
Abstract
Significant amounts of the greenhouse gas methane (CH4) are released into the atmosphere worldwide via freshwater sources. The surface methane maximum (SMM), where methane is supersaturated in surface water, has been observed in aquatic systems and contributes significantly to emissions. However, little is known about the temporal and spatial variability of SMM or the mechanisms underlying its development in artificial reservoirs. Here, the community composition of methanogens as major methane producers in the water column and the mcrA gene was investigated, and the cause of surface methane supersaturation was analyzed. In accordance with the findings, elevated methane concentration of SMM in the transition zone, with an annually methane emission flux 2.47 times higher than the reservoir average on a large and deep reservoir. In the transition zone, methanogens with mcrA gene abundances ranging from 0.5 × 103-1.45 × 104 copies/L were found. Methanobacterium, Methanoseata and Methanosarcina were the three dominate methanogens, using both acetic acid and H2/CO2 pathways. In summary, this study contributes to our comprehension of CH4 fluxes and their role in the atmospheric methane budget. Moreover, it offers biological proof of methane generation, which could aid in understanding the role of microbial methanogenesis in aerobic water.
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Affiliation(s)
- Shuwen Ma
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Meilin Yang
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Xueping Chen
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
| | - Fushun Wang
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Yue Xia
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Peifan Xu
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Jing Ma
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Chai Luo
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Canran Zhou
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Tian Xu
- School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China
| | - Yongguan Zhu
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
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7
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Peoples LM, Dore JE, Bilbrey EM, Vick-Majors TJ, Ranieri JR, Evans KA, Ross AM, Devlin SP, Church MJ. Oxic methane production from methylphosphonate in a large oligotrophic lake: limitation by substrate and organic carbon supply. Appl Environ Microbiol 2023; 89:e0109723. [PMID: 38032216 PMCID: PMC10734540 DOI: 10.1128/aem.01097-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE Methane is an important greenhouse gas that is typically produced under anoxic conditions. We show that methane is supersaturated in a large oligotrophic lake despite the presence of oxygen. Metagenomic sequencing indicates that diverse, widespread microorganisms may contribute to the oxic production of methane through the cleavage of methylphosphonate. We experimentally demonstrate that these organisms, especially members of the genus Acidovorax, can produce methane through this process. However, appreciable rates of methane production only occurred when both methylphosphonate and labile sources of carbon were added, indicating that this process may be limited to specific niches and may not be completely responsible for methane concentrations in Flathead Lake. This work adds to our understanding of methane dynamics by describing the organisms and the rates at which they can produce methane through an oxic pathway in a representative oligotrophic lake.
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Affiliation(s)
- Logan M. Peoples
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
| | - John E. Dore
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA
| | - Evan M. Bilbrey
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho, USA
| | - Trista J. Vick-Majors
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - John R. Ranieri
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
| | - Kate A. Evans
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
| | - Abigail M. Ross
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
| | - Shawn P. Devlin
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
| | - Matthew J. Church
- Flathead Lake Biological Station, University of Montana, Polson, Montana, USA
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von Arx JN, Kidane AT, Philippi M, Mohr W, Lavik G, Schorn S, Kuypers MMM, Milucka J. Methylphosphonate-driven methane formation and its link to primary production in the oligotrophic North Atlantic. Nat Commun 2023; 14:6529. [PMID: 37845220 PMCID: PMC10579326 DOI: 10.1038/s41467-023-42304-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 10/06/2023] [Indexed: 10/18/2023] Open
Abstract
Methylphosphonate is an organic phosphorus compound used by microorganisms when phosphate, a key nutrient limiting growth in most marine surface waters, becomes unavailable. Microbial methylphosphonate use can result in the formation of methane, a potent greenhouse gas, in oxic waters where methane production is traditionally unexpected. The extent and controlling factors of such aerobic methane formation remain underexplored. Here, we show high potential net rates of methylphosphonate-driven methane formation (median 0.4 nmol methane L-1 d-1) in the upper water column of the western tropical North Atlantic. The rates are repressed but still quantifiable in the presence of in-situ or added phosphate, suggesting that some methylphosphonate-driven methane formation persists in phosphate-replete waters. The genetic potential for methylphosphonate utilisation is present in and transcribed by key photo- and heterotrophic microbial taxa, such as Pelagibacterales, SAR116, and Trichodesmium. While the large cyanobacterial nitrogen-fixers dominate in the surface layer, phosphonate utilisation by Alphaproteobacteria appears to become more important in deeper depths. We estimate that at our study site, a substantial part (median 11%) of the measured surface carbon fixation can be sustained by phosphorus liberated from phosphonate utilisation, highlighting the ecological importance of phosphonates in the carbon cycle of the oligotrophic ocean.
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Affiliation(s)
- Jan N von Arx
- Max Planck Institute for Marine Microbiology, Bremen, Germany.
| | - Abiel T Kidane
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Miriam Philippi
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Wiebke Mohr
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Gaute Lavik
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sina Schorn
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | | | - Jana Milucka
- Max Planck Institute for Marine Microbiology, Bremen, Germany
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Ugocsai M, Bársony A, Varga RA, Gajda Á, Vida N, Lajkó N, Rónaszéki B, Tóth G, Boros M, Érces D, Varga G. Conjugation with Tris Decreases the Risk of Ketoprofen-Induced Mucosal Damage and Reduces Inflammation-Associated Methane Production in a Rat Model of Colitis. Pharmaceutics 2023; 15:2329. [PMID: 37765297 PMCID: PMC10535093 DOI: 10.3390/pharmaceutics15092329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
We have designed a new compound from the non-steroidal anti-inflammatory drug (NSAID) ketoprofen (Ket) and 2-amino-2-(hydroxymethyl)-1,3-propanediol (Tris) precursors, with the aim to reduce the gastrointestinal (GI) side effects of NSAID therapies. We investigated mucosal reactions in a standard rat model of colitis together with methane generation as a possible indicator of pro-inflammatory activation under this condition (approval number: V./148/2013). Whole-body methane production (photoacoustic spectroscopy) and serosal microcirculation (intravital videomicroscopy) were measured, and mucosal damage was assessed (conventional histology; in vivo laser-scanning endomicroscopy). Inflammatory markers were measured from tissue and blood samples. Colitis induced an inflammatory response, morphological colonic damage and increased methane output. Ket treatment lowered inflammatory activation and colonic mucosal injury, but macroscopic gastric bleeding and increased methane output were present. Ket-Tris reduced inflammatory activation, methane emission and colonic mucosal damage, without inducing gastric injury. Conjugation with Tris reduces the GI side effects of Ket and still decreases the inflammatory response in experimental colitis. Methane output correlates with the mucosal inflammatory response and non-invasively demonstrates the effects of anti-inflammatory treatments.
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Affiliation(s)
- Melinda Ugocsai
- Department of Orthopaedics, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Hungary
| | - Anett Bársony
- Department of Surgery, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Hungary
| | - Réka Anna Varga
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
| | - Ámos Gajda
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
| | - Noémi Vida
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
| | - Norbert Lajkó
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
| | - Benedek Rónaszéki
- Second Department of Internal Medicine and Cardiology Center, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Hungary
| | - Gábor Tóth
- Department of Medical Chemistry, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary
- ELKH-SZTE Biomimetic Systems Research Group, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary
| | - Mihály Boros
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
| | - Dániel Érces
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
| | - Gabriella Varga
- Institute of Surgical Research, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary (D.É.)
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10
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Alowaifeer AM, Wang Q, Bothner B, Sibert RJ, Joye SB, McDermott TR. Aerobic methane synthesis and dynamics in a river water environment. LIMNOLOGY AND OCEANOGRAPHY 2023; 68:1762-1774. [PMID: 37928964 PMCID: PMC10624334 DOI: 10.1002/lno.12383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 05/21/2023] [Indexed: 11/07/2023]
Abstract
Reports of aerobic biogenic methane (CH 4 ) have generated new views about CH 4 sources in nature. We examine this phenomenon in the free-flowing Yellowstone river wherein CH 4 concentrations were tracked as a function of environmental conditions, phototrophic microorganisms (using chlorophyll a , Chl a , as proxy), as well as targeted methylated amines known to be associated with this process. CH 4 was positively correlated with temperature and Chl a , although diurnal measurements showed CH 4 concentrations were greatest during the night and lowest during maximal solar irradiation. CH 4 efflux from the river surface was greater in quiescent edge waters (71-94 μmol m-2 d) than from open flowing current (~ 57 μmol m-2 d). Attempts to increase flux by disturbing the benthic environment in the quiescent water directly below (~ 1.0 m deep) or at varying distances (0-5 m) upstream of the flux chamber failed to increase surface flux. Glycine betaine (GB), dimethylamine and methylamine (MMA) were observed throughout the summer-long study, increasing during a period coinciding with a marked decline in Chl a , suggesting a lytic event led to their release; however, this did not correspond to increased CH 4 concentrations. Spiking river water with GB or MMA yielded significantly greater CH 4 than nonspiked controls, illustrating the metabolic potential of the river microbiome. In summary, this study provides evidence that: (1) phototrophic microorganisms are involved in CH 4 synthesis in a river environment; (2) the river microbiome possesses the metabolic potential to convert methylated amines to CH 4 ; and (3) river CH 4 concentrations are dynamic diurnally as well as during the summer active months.
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Affiliation(s)
- Abdullah M. Alowaifeer
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA
| | - Qian Wang
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Ryan J. Sibert
- Department of Marine Science, University of Georgia, Athens, Georgia, USA
| | - Samantha B. Joye
- Department of Marine Science, University of Georgia, Athens, Georgia, USA
| | - Timothy R. McDermott
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana, USA
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11
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Rucker HR, Ely TD, LaRowe DE, Giovannelli D, Price RE. Quantifying the Bioavailable Energy in an Ancient Hydrothermal Vent on Mars and a Modern Earth-Based Analog. ASTROBIOLOGY 2023; 23:431-445. [PMID: 36862508 DOI: 10.1089/ast.2022.0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Putative alkaline hydrothermal systems on Noachian Mars were potentially habitable environments for microorganisms. However, the types of reactions that could have fueled microbial life in such systems and the amount of energy available from them have not been quantitatively constrained. In this study, we use thermodynamic modeling to calculate which catabolic reactions could have supported ancient life in a saponite-precipitating hydrothermal vent system in the Eridania basin on Mars. To further evaluate what this could mean for microbial life, we evaluated the energy potential of an analog site in Iceland, the Strytan Hydrothermal Field. Results show that, of the 84 relevant redox reactions that were considered, the highest energy-yielding reactions in the Eridania hydrothermal system were dominated by methane formation. By contrast, Gibbs energy calculations carried out for Strytan indicate that the most energetically favorable reactions are CO2 and O2 reduction coupled to H2 oxidation. In particular, our calculations indicate that an ancient hydrothermal system within the Eridania basin could have been a habitable environment for methanogens using NH4+ as an electron acceptor. Differences in Gibbs energies between the two systems were largely determined by oxygen-its presence on Earth and absence on Mars. However, Strytan can serve as a useful analog for Eridania when studying methane-producing reactions that do not involve O2.
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Affiliation(s)
- Holly R Rucker
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Tucker D Ely
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, USA
- 39Alpha Research, Tempe, Arizona, USA
| | - Douglas E LaRowe
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
| | - Donato Giovannelli
- Department of Biology, University of Naples "Federico II," Naples, Italy
| | - Roy E Price
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, USA
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12
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Bueno de Mesquita CP, Wu D, Tringe SG. Methyl-Based Methanogenesis: an Ecological and Genomic Review. Microbiol Mol Biol Rev 2023; 87:e0002422. [PMID: 36692297 PMCID: PMC10029344 DOI: 10.1128/mmbr.00024-22] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Methyl-based methanogenesis is one of three broad categories of archaeal anaerobic methanogenesis, including both the methyl dismutation (methylotrophic) pathway and the methyl-reducing (also known as hydrogen-dependent methylotrophic) pathway. Methyl-based methanogenesis is increasingly recognized as an important source of methane in a variety of environments. Here, we provide an overview of methyl-based methanogenesis research, including the conditions under which methyl-based methanogenesis can be a dominant source of methane emissions, experimental methods for distinguishing different pathways of methane production, molecular details of the biochemical pathways involved, and the genes and organisms involved in these processes. We also identify the current gaps in knowledge and present a genomic and metagenomic survey of methyl-based methanogenesis genes, highlighting the diversity of methyl-based methanogens at multiple taxonomic levels and the widespread distribution of known methyl-based methanogenesis genes and families across different environments.
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Affiliation(s)
| | - Dongying Wu
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Susannah G. Tringe
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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13
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Ramírez GA, Bar-Shalom R, Furlan A, Romeo R, Gavagnin M, Calabrese G, Garber AI, Steindler L. Bacterial aerobic methane cycling by the marine sponge-associated microbiome. MICROBIOME 2023; 11:49. [PMID: 36899421 PMCID: PMC9999580 DOI: 10.1186/s40168-023-01467-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Methanotrophy by the sponge-hosted microbiome has been mainly reported in the ecological context of deep-sea hydrocarbon seep niches where methane is either produced geothermically or via anaerobic methanogenic archaea inhabiting the sulfate-depleted sediments. However, methane-oxidizing bacteria from the candidate phylum Binatota have recently been described and shown to be present in oxic shallow-water marine sponges, where sources of methane remain undescribed. RESULTS Here, using an integrative -omics approach, we provide evidence for sponge-hosted bacterial methane synthesis occurring in fully oxygenated shallow-water habitats. Specifically, we suggest methane generation occurs via at least two independent pathways involving methylamine and methylphosphonate transformations that, concomitantly to aerobic methane production, generate bioavailable nitrogen and phosphate, respectively. Methylphosphonate may be sourced from seawater continuously filtered by the sponge host. Methylamines may also be externally sourced or, alternatively, generated by a multi-step metabolic process where carnitine, derived from sponge cell debris, is transformed to methylamine by different sponge-hosted microbial lineages. Finally, methanotrophs specialized in pigment production, affiliated to the phylum Binatota, may provide a photoprotective function, closing a previously undescribed C1-metabolic loop that involves both the sponge host and specific members of the associated microbial community. CONCLUSION Given the global distribution of this ancient animal lineage and their remarkable water filtration activity, sponge-hosted methane cycling may affect methane supersaturation in oxic coastal environments. Depending on the net balance between methane production and consumption, sponges may serve as marine sources or sinks of this potent greenhouse gas. Video Abstract.
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Affiliation(s)
- Gustavo A Ramírez
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, Israel
- Present address: Department of Biological Sciences, California State University, Los Angeles, CA, USA
| | - Rinat Bar-Shalom
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, Israel
| | - Andrea Furlan
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, Israel
| | - Roberto Romeo
- Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, Italy
| | - Michelle Gavagnin
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, Israel
| | - Gianluca Calabrese
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, Israel
| | - Arkadiy I Garber
- School of Life Science, Arizona State University, Tempe, AZ, USA
| | - Laura Steindler
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, 199 Aba Khoushy Ave., Mount Carmel, Haifa, Israel.
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14
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Cheney AM, Costello SM, Pinkham NV, Waldum A, Broadaway SC, Cotrina-Vidal M, Mergy M, Tripet B, Kominsky DJ, Grifka-Walk HM, Kaufmann H, Norcliffe-Kaufmann L, Peach JT, Bothner B, Lefcort F, Copié V, Walk ST. Gut microbiome dysbiosis drives metabolic dysfunction in Familial dysautonomia. Nat Commun 2023; 14:218. [PMID: 36639365 PMCID: PMC9839693 DOI: 10.1038/s41467-023-35787-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 12/18/2022] [Indexed: 01/15/2023] Open
Abstract
Familial dysautonomia (FD) is a rare genetic neurologic disorder caused by impaired neuronal development and progressive degeneration of both the peripheral and central nervous systems. FD is monogenic, with >99.4% of patients sharing an identical point mutation in the elongator acetyltransferase complex subunit 1 (ELP1) gene, providing a relatively simple genetic background in which to identify modifiable factors that influence pathology. Gastrointestinal symptoms and metabolic deficits are common among FD patients, which supports the hypothesis that the gut microbiome and metabolome are altered and dysfunctional compared to healthy individuals. Here we show significant differences in gut microbiome composition (16 S rRNA gene sequencing of stool samples) and NMR-based stool and serum metabolomes between a cohort of FD patients (~14% of patients worldwide) and their cohabitating, healthy relatives. We show that key observations in human subjects are recapitulated in a neuron-specific Elp1-deficient mouse model, and that cohousing mutant and littermate control mice ameliorates gut microbiome dysbiosis, improves deficits in gut transit, and reduces disease severity. Our results provide evidence that neurologic deficits in FD alter the structure and function of the gut microbiome, which shifts overall host metabolism to perpetuate further neurodegeneration.
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Affiliation(s)
- Alexandra M Cheney
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Stephanann M Costello
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Nicholas V Pinkham
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Annie Waldum
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Susan C Broadaway
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Maria Cotrina-Vidal
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Marc Mergy
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Brian Tripet
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Douglas J Kominsky
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Heather M Grifka-Walk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA
| | - Horacio Kaufmann
- Department of Neurology, New York University School of Medicine, New York, NY, USA
| | | | - Jesse T Peach
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
| | - Valérie Copié
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
| | - Seth T Walk
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
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15
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Kim HH, Saha S, Hwang JH, Hosen MA, Ahn YT, Park YK, Khan MA, Jeon BH. Integrative biohydrogen- and biomethane-producing bioprocesses for comprehensive production of biohythane. BIORESOURCE TECHNOLOGY 2022; 365:128145. [PMID: 36257521 DOI: 10.1016/j.biortech.2022.128145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
The production of biohythane, a combination of energy-dense hydrogen and methane, from the anaerobic digestion of low-cost organic wastes has attracted attention as a potential candidate for the transition to a sustainable circular economy. Substantial research has been initiated to upscale the process engineering to establish a hythane-based economy by addressing major challenges associated with the process and product upgrading. This review provides an overview of the feasibility of biohythane production in various anaerobic digestion systems (single-stage, dual-stage) and possible technologies to upgrade biohythane to hydrogen-enriched renewable natural gas. The main goal of this review is to promote research in biohythane production technology by outlining critical needs, including meta-omics and metabolic engineering approaches for the advancements in biohythane production technology.
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Affiliation(s)
- Hoo Hugo Kim
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Shouvik Saha
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Jae-Hoon Hwang
- Department of Civil, Environmental, and Construction Engineering, University of Central Florida, Orlando, FL 32816-2450, USA
| | - Md Aoulad Hosen
- Department of Microbiology, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh
| | - Yong-Tae Ahn
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Young-Kwon Park
- School of Environmental Engineering, University of Seoul, Seoul 02504, Republic of Korea
| | - Moonis Ali Khan
- Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea.
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16
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Mao SH, Zhang HH, Zhuang GC, Li XJ, Liu Q, Zhou Z, Wang WL, Li CY, Lu KY, Liu XT, Montgomery A, Joye SB, Zhang YZ, Yang GP. Aerobic oxidation of methane significantly reduces global diffusive methane emissions from shallow marine waters. Nat Commun 2022; 13:7309. [PMID: 36437260 PMCID: PMC9701681 DOI: 10.1038/s41467-022-35082-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 11/18/2022] [Indexed: 11/28/2022] Open
Abstract
Methane is supersaturated in surface seawater and shallow coastal waters dominate global ocean methane emissions to the atmosphere. Aerobic methane oxidation (MOx) can reduce atmospheric evasion, but the magnitude and control of MOx remain poorly understood. Here we investigate methane sources and fates in the East China Sea and map global MOx rates in shallow waters by training machine-learning models. We show methane is produced during methylphosphonate decomposition under phosphate-limiting conditions and sedimentary release is also source of methane. High MOx rates observed in these productive coastal waters are correlated with methanotrophic activity and biomass. By merging the measured MOx rates with methane concentrations and other variables from a global database, we predict MOx rates and estimate that half of methane, amounting to 1.8 ± 2.7 Tg, is consumed annually in near-shore waters (<50 m), suggesting that aerobic methanotrophy is an important sink that significantly constrains global methane emissions.
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Affiliation(s)
- Shi-Hai Mao
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
| | - Hong-Hai Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
| | - Guang-Chao Zhuang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China.
| | - Xiao-Jun Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
| | - Qiao Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
| | - Zhen Zhou
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China
| | - Wei-Lei Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, China
| | - Chun-Yang Li
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266100, China
| | - Ke-Yu Lu
- Department of Earth Sciences, University College London, London, WC1E 6BS, UK
| | - Xi-Ting Liu
- College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China
| | - Andrew Montgomery
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Samantha B Joye
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
| | - Yu-Zhong Zhang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266100, China
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Gui-Peng Yang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
- College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China.
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17
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Perez-Coronel E, Michael Beman J. Multiple sources of aerobic methane production in aquatic ecosystems include bacterial photosynthesis. Nat Commun 2022; 13:6454. [PMID: 36309500 PMCID: PMC9617973 DOI: 10.1038/s41467-022-34105-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 10/13/2022] [Indexed: 12/25/2022] Open
Abstract
Aquatic ecosystems are globally significant sources of the greenhouse gas methane to the atmosphere. Until recently, methane production was thought to be a strictly anaerobic process confined primarily to anoxic sediments. However, supersaturation of methane in oxygenated waters has been consistently observed in lakes and the ocean (termed the 'methane paradox'), indicating that methane can be produced under oxic conditions through unclear mechanisms. Here we show aerobic methane production from multiple sources in freshwater incubation experiments under different treatments and based on biogeochemical, metagenomic, and metatranscriptomic data. We find that aerobic methane production appears to be associated with (bacterio)chlorophyll metabolism and photosynthesis, as well as with Proteobacterial degradation of methylphosphonate. Genes encoding pathways for putative photosynthetic- and methylphosphonate-based methane production also co-occur in Proteobacterial metagenome-assembled genomes. Our findings provide insight into known mechanisms of aerobic methane production, and suggest a potential co-occurring mechanism associated with bacterial photosynthesis in aquatic ecosystems.
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Affiliation(s)
- Elisabet Perez-Coronel
- grid.266096.d0000 0001 0049 1282Environmental Systems and Sierra Nevada Research Institute, University of California Merced, Merced, CA USA
| | - J. Michael Beman
- grid.266096.d0000 0001 0049 1282Environmental Systems and Sierra Nevada Research Institute, University of California Merced, Merced, CA USA
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18
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Huang X, Liu X, Xue Y, Pan B, Xiao L, Wang S, Lever MA, Hinrichs KU, Inagaki F, Liu C. Methane Production by Facultative Anaerobic Wood-Rot Fungi via a New Halomethane-Dependent Pathway. Microbiol Spectr 2022; 10:e0170022. [PMID: 36102652 PMCID: PMC9604129 DOI: 10.1128/spectrum.01700-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/26/2022] [Indexed: 12/31/2022] Open
Abstract
The greenhouse gas methane (CH4) is of pivotal importance for Earth's climate system and as a human energy source. A significant fraction of this CH4 is produced by anaerobic Archaea. Here, we describe the first CH4 production by facultative anaerobic wood-rot fungi during growth on hydroxylated/carboxylated aromatic compounds, including lignin and lignite. The amount of CH4 produced by fungi is positively correlated with the amount of CH3Cl produced during the rapid growth period of the fungus. Biochemical, genetic, and stable isotopic tracer analyses reveal the existence of a novel halomethane-dependent fungal CH4 production pathway during the degradation of phenol and benzoic acid monomers and polymers and utilization of cyclic sugars. Even though this halomethane-dependent pathway may only play a side role in anaerobic fungal activity, it could represent a globally significant, previously overlooked source of biogenic CH4 in natural ecosystems. IMPORTANCE Here, we demonstrate that wood-rot fungi produce methane anaerobically without the involvement of methanogenic archaea via a new, halomethane-dependent pathway. These findings of an anaerobic fungal methane formation pathway open another avenue in methane research and will further assist with current efforts in the identification of the processes involved and their ecological implications.
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Affiliation(s)
- Xin Huang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Xuan Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Yarong Xue
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Bingcai Pan
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu, China
| | - Lei Xiao
- School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou, Jiangsu, China
| | - Shuijuan Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Mark A. Lever
- Department of Environmental Systems Science, ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, Zürich, Switzerland
| | - Kai-Uwe Hinrichs
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Fumio Inagaki
- Mantle Drilling Promotion Office, Institute for Marine-Earth Exploration and Engineering (MarE3), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan
- Department of Earth Sciences, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Changhong Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
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19
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Al-Shayeb B, Schoelmerich MC, West-Roberts J, Valentin-Alvarado LE, Sachdeva R, Mullen S, Crits-Christoph A, Wilkins MJ, Williams KH, Doudna JA, Banfield JF. Borgs are giant genetic elements with potential to expand metabolic capacity. Nature 2022; 610:731-736. [PMID: 36261517 PMCID: PMC9605863 DOI: 10.1038/s41586-022-05256-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/22/2022] [Indexed: 12/03/2022]
Abstract
Anaerobic methane oxidation exerts a key control on greenhouse gas emissions1, yet factors that modulate the activity of microorganisms performing this function remain poorly understood. Here we discovered extraordinarily large, diverse DNA sequences that primarily encode hypothetical proteins through studying groundwater, sediments and wetland soil where methane production and oxidation occur. Four curated, complete genomes are linear, up to approximately 1 Mb in length and share genome organization, including replichore structure, long inverted terminal repeats and genome-wide unique perfect tandem direct repeats that are intergenic or generate amino acid repeats. We infer that these are highly divergent archaeal extrachromosomal elements with a distinct evolutionary origin. Gene sequence similarity, phylogeny and local divergence of sequence composition indicate that many of their genes were assimilated from methane-oxidizing Methanoperedens archaea. We refer to these elements as 'Borgs'. We identified at least 19 different Borg types coexisting with Methanoperedens spp. in four distinct ecosystems. Borgs provide methane-oxidizing Methanoperedens archaea access to genes encoding proteins involved in redox reactions and energy conservation (for example, clusters of multihaem cytochromes and methyl coenzyme M reductase). These data suggest that Borgs might have previously unrecognized roles in the metabolism of this group of archaea, which are known to modulate greenhouse gas emissions, but further studies are now needed to establish their functional relevance.
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Affiliation(s)
- Basem Al-Shayeb
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | | | - Jacob West-Roberts
- Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Luis E Valentin-Alvarado
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Rohan Sachdeva
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Earth and Planetary Science, University of California, Berkeley, CA, USA
| | - Susan Mullen
- Earth and Planetary Science, University of California, Berkeley, CA, USA
| | - Alexander Crits-Christoph
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Michael J Wilkins
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Kenneth H Williams
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Rocky Mountain Biological Lab, Gothic, CO, USA
| | - Jennifer A Doudna
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Environmental Science, Policy and Management, University of California, Berkeley, CA, USA.
- Earth and Planetary Science, University of California, Berkeley, CA, USA.
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- The University of Melbourne, Melbourne, Victoria, Australia.
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20
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Pi HW, Lin JJ, Chen CA, Wang PH, Chiang YR, Huang CC, Young CC, Li WH. Origin and evolution of nitrogen fixation in prokaryotes. Mol Biol Evol 2022; 39:6673025. [PMID: 35993177 PMCID: PMC9447857 DOI: 10.1093/molbev/msac181] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The origin of nitrogen fixation is an important issue in evolutionary biology. While nitrogen is required by all living organisms, only a small fraction of bacteria and archaea can fix nitrogen. The prevailing view is that nitrogen fixation first evolved in archaea and was later transferred to bacteria. However, nitrogen-fixing (Nif) bacteria are far larger in number and far more diverse in ecological niches than Nif archaea. We, therefore, propose the bacteria-first hypothesis, which postulates that nitrogen fixation first evolved in bacteria and was later transferred to archaea. As >30,000 prokaryotic genomes have been sequenced, we conduct an in-depth comparison of the two hypotheses. We first identify the six genes involved in nitrogen fixation in all sequenced prokaryotic genomes and then reconstruct phylogenetic trees using the six Nif proteins individually or in combination. In each of these trees, the earliest lineages are bacterial Nif protein sequences and in the oldest clade (group) the archaeal sequences are all nested inside bacterial sequences, suggesting that the Nif proteins first evolved in bacteria. The bacteria-first hypothesis is further supported by the observation that the majority of Nif archaea carry the major bacterial Mo (molybdenum) transporter (ModABC) rather than the archaeal Mo transporter (WtpABC). Moreover, in our phylogeny of all available ModA and WtpA protein sequences, the earliest lineages are bacterial sequences while archaeal sequences are nested inside bacterial sequences. Furthermore, the bacteria-first hypothesis is supported by available isotopic data. In conclusion, our study strongly supports the bacteria-first hypothesis.
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Affiliation(s)
- Hong Wei Pi
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taiwan.,Biodiversity Research Center, Academia Sinica, Taipei, Taiwan 11529
| | - Jinn Jy Lin
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan 11529
| | - Chi An Chen
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan 11529.,Genome and Systems Biology Degree Program, Academia Sinica and National Taiwan University, Taipei 10617, Taiwan
| | - Po Hsiang Wang
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan, Taiwan 32001.,Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan 145-0061
| | - Yin Ru Chiang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan 11529
| | - Chieh Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan 402
| | - Chiu Chung Young
- Department of Soil and Environmental Sciences, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, Taiwan 402
| | - Wen Hsiung Li
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan 11529.,Department of Ecology and Evolution, University of Chicago, Chicago 60637, USA
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21
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Thottathil SD, Reis PCJ, Prairie YT. Magnitude and Drivers of Oxic Methane Production in Small Temperate Lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11041-11050. [PMID: 35820110 DOI: 10.1021/acs.est.2c01730] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Methanogenesis is traditionally considered as a strictly anaerobic process. Recent evidence suggests instead that the ubiquitous methane (CH4) oversaturation found in freshwater lakes is sustained, at least partially, by methanogenesis in oxic conditions. Although this paradigm shift is rapidly gaining acceptance, the magnitude and regulation of oxic CH4 production (OMP) have remained ambiguous. Based on the summer CH4 mass balance in the surface mixed layer (SML) of five small temperate lakes (surface area, SA, of 0.008-0.44 km2), we show that OMP (range of 0.01 ± 0.01 to 0.52 ± 0.04 μmol L-1 day-1) is linked to the concentrations of chlorophyll-a, total phosphorus, and dissolved organic carbon. The stable carbon isotopic mass balance of CH4 (δ13C-CH4) indicates direct photoautotrophic release as the most likely source of oxic CH4. Furthermore, we show that the oxic CH4 contribution to the SML CH4 saturation and emission is an inverse function of the ratio of the sediment area to the SML volume in lakes as small as 0.06 km2. Given that global lake CH4 emissions are dominated by small lakes (SA of <1 km2), the large contribution of oxic CH4 production (up to 76%) observed in this study suggests that OMP can contribute significantly to global CH4 emissions.
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Affiliation(s)
- Shoji D Thottathil
- Department of Environmental Science, SRM University AP, Amaravati, Mangalagiri, Andhra Pradesh 522 502, India
| | - Paula C J Reis
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
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22
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Warren M, Galpin I, Bachtiger F, Gibson MI, Sosso GC. Ice Recrystallization Inhibition by Amino Acids: The Curious Case of Alpha- and Beta-Alanine. J Phys Chem Lett 2022; 13:2237-2244. [PMID: 35238571 PMCID: PMC9007522 DOI: 10.1021/acs.jpclett.1c04080] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Extremophiles produce macromolecules which inhibit ice recrystallization, but there is increasing interest in discovering and developing small molecules that can modulate ice growth. Realizing their potential requires an understanding of how these molecules function at the atomistic level. Here, we report the discovery that the amino acid l-α-alanine demonstrates ice recrystallization inhibition (IRI) activity, functioning at 100 mM (∼10 mg/mL). We combined experimental assays with molecular simulations to investigate this IRI agent, drawing comparison to β-alanine, an isomer of l-α-alanine which displays no IRI activity. We found that the difference in the IRI activity of these molecules does not originate from their ice binding affinity, but from their capacity to (not) become overgrown, dictated by the degree of structural (in)compatibility within the growing ice lattice. These findings shed new light on the microscopic mechanisms of small molecule cryoprotectants, particularly in terms of their molecular structure and overgrowth by ice.
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Affiliation(s)
- Matthew
T. Warren
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
- Warwick
Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Iain Galpin
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Fabienne Bachtiger
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Matthew I. Gibson
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
- Warwick
Medical School, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Gabriele C. Sosso
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
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23
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Ernst L, Steinfeld B, Barayeu U, Klintzsch T, Kurth M, Grimm D, Dick TP, Rebelein JG, Bischofs IB, Keppler F. Methane formation driven by reactive oxygen species across all living organisms. Nature 2022; 603:482-487. [PMID: 35264795 DOI: 10.1038/s41586-022-04511-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 02/03/2022] [Indexed: 11/09/2022]
Abstract
Methane (CH4), the most abundant hydrocarbon in the atmosphere, originates largely from biogenic sources1 linked to an increasing number of organisms occurring in oxic and anoxic environments. Traditionally, biogenic CH4 has been regarded as the final product of anoxic decomposition of organic matter by methanogenic archaea. However, plants2,3, fungi4, algae5 and cyanobacteria6 can produce CH4 in the presence of oxygen. Although methanogens are known to produce CH4 enzymatically during anaerobic energy metabolism7, the requirements and pathways for CH4 production by non-methanogenic cells are poorly understood. Here, we demonstrate that CH4 formation by Bacillus subtilis and Escherichia coli is triggered by free iron and reactive oxygen species (ROS), which are generated by metabolic activity and enhanced by oxidative stress. ROS-induced methyl radicals, which are derived from organic compounds containing sulfur- or nitrogen-bonded methyl groups, are key intermediates that ultimately lead to CH4 production. We further show CH4 production by many other model organisms from the Bacteria, Archaea and Eukarya domains, including in several human cell lines. All these organisms respond to inducers of oxidative stress by enhanced CH4 formation. Our results imply that all living cells probably possess a common mechanism of CH4 formation that is based on interactions among ROS, iron and methyl donors, opening new perspectives for understanding biochemical CH4 formation and cycling.
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Affiliation(s)
- Leonard Ernst
- BioQuant Center, Heidelberg University, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany. .,Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.
| | - Benedikt Steinfeld
- BioQuant Center, Heidelberg University, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany.,Zentrum für Molekulare Biologie Heidelberg (ZMBH), Heidelberg University, Heidelberg, Germany
| | - Uladzimir Barayeu
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Thomas Klintzsch
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.,Department for Plant Nutrition, Gießen University, Gießen, Germany
| | - Markus Kurth
- Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Dirk Grimm
- BioQuant Center, Heidelberg University, Heidelberg, Germany.,Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Tobias P Dick
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | | | - Ilka B Bischofs
- BioQuant Center, Heidelberg University, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany. .,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany.
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany. .,Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany.
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24
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Bueno de Mesquita CP, Zhou J, Theroux S, Tringe SG. Methylphosphonate Degradation and Salt-Tolerance Genes of Two Novel Halophilic Marivita Metagenome-Assembled Genomes from Unrestored Solar Salterns. Genes (Basel) 2022; 13:genes13010148. [PMID: 35052488 PMCID: PMC8774927 DOI: 10.3390/genes13010148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/30/2022] Open
Abstract
Aerobic bacteria that degrade methylphosphonates and produce methane as a byproduct have emerged as key players in marine carbon and phosphorus cycles. Here, we present two new draft genome sequences of the genus Marivita that were assembled from metagenomes from hypersaline former industrial salterns and compare them to five other Marivita reference genomes. Phylogenetic analyses suggest that both of these metagenome-assembled genomes (MAGs) represent new species in the genus. Average nucleotide identities to the closest taxon were <85%. The MAGs were assembled with SPAdes, binned with MetaBAT, and curated with scaffold extension and reassembly. Both genomes contained the phnCDEGHIJLMP suite of genes encoding the full C-P lyase pathway of methylphosphonate degradation and were significantly more abundant in two former industrial salterns than in nearby reference and restored wetlands, which have lower salinity levels and lower methane emissions than the salterns. These organisms contain a variety of compatible solute biosynthesis and transporter genes to cope with high salinity levels but harbor only slightly acidic proteomes (mean isoelectric point of 6.48).
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Affiliation(s)
- Clifton P. Bueno de Mesquita
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; (C.P.B.d.M.); (J.Z.)
| | - Jinglie Zhou
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; (C.P.B.d.M.); (J.Z.)
| | - Susanna Theroux
- Southern California Coastal Water Research Project, Costa Mesa, CA 92626, USA;
| | - Susannah G. Tringe
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; (C.P.B.d.M.); (J.Z.)
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Correspondence:
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