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Aguzzi J, Cuadros J, Dartnell L, Costa C, Violino S, Canfora L, Danovaro R, Robinson NJ, Giovannelli D, Flögel S, Stefanni S, Chatzievangelou D, Marini S, Picardi G, Foing B. Marine Science Can Contribute to the Search for Extra-Terrestrial Life. Life (Basel) 2024; 14:676. [PMID: 38929660 PMCID: PMC11205085 DOI: 10.3390/life14060676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 05/14/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024] Open
Abstract
Life on our planet likely evolved in the ocean, and thus exo-oceans are key habitats to search for extraterrestrial life. We conducted a data-driven bibliographic survey on the astrobiology literature to identify emerging research trends with marine science for future synergies in the exploration for extraterrestrial life in exo-oceans. Based on search queries, we identified 2592 published items since 1963. The current literature falls into three major groups of terms focusing on (1) the search for life on Mars, (2) astrobiology within our Solar System with reference to icy moons and their exo-oceans, and (3) astronomical and biological parameters for planetary habitability. We also identified that the most prominent research keywords form three key-groups focusing on (1) using terrestrial environments as proxies for Martian environments, centred on extremophiles and biosignatures, (2) habitable zones outside of "Goldilocks" orbital ranges, centred on ice planets, and (3) the atmosphere, magnetic field, and geology in relation to planets' habitable conditions, centred on water-based oceans.
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Affiliation(s)
- Jacopo Aguzzi
- Instituto de Ciencias del Mar (ICM)—CSIC, 08003 Barcelona, Spain; (N.J.R.); (D.C.); (G.P.)
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (S.S.); (S.M.)
| | - Javier Cuadros
- Natural History Museum, Cromwell Road, London SW7 5D, UK;
| | - Lewis Dartnell
- School of Life Sciences, University of Westminster, 115 New Cavendish St, London W1W 6UW, UK;
| | - Corrado Costa
- Consiglio per la Ricerca in Agricoltura e l’Analisi Dell’Economia Agraria—Centro di Ricerca Ingegneria e Trasformazioni Agroalimentari, 00015 Monterotondo, Italy; (C.C.); (S.V.)
| | - Simona Violino
- Consiglio per la Ricerca in Agricoltura e l’Analisi Dell’Economia Agraria—Centro di Ricerca Ingegneria e Trasformazioni Agroalimentari, 00015 Monterotondo, Italy; (C.C.); (S.V.)
| | - Loredana Canfora
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’economia Agraria—Centro di Ricerca Agricoltura e Ambiente, 00182 Roma, Italy;
| | - Roberto Danovaro
- Department of Life and Environmental Sciences, Polytechnic University of Marcs (UNIVPM), 60131 Ancona, Italy;
| | - Nathan Jack Robinson
- Instituto de Ciencias del Mar (ICM)—CSIC, 08003 Barcelona, Spain; (N.J.R.); (D.C.); (G.P.)
| | - Donato Giovannelli
- Department of Biology, University of Naples Federico II, 80138 Naples, Italy;
- National Research Council—Institute of Marine Biological Resources and Biotechnologies (CNR-IRBIM), 60125 Ancona, Italy
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ 08901, USA
- Marine Chemistry, Geochemistry Department—Woods Hole Oceanographic Institution, Falmouth, MA 02543, USA
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Sascha Flögel
- GEOMAR Helmholtz Centre for Ocean Research, 24106 Kiel, Germany;
| | - Sergio Stefanni
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (S.S.); (S.M.)
| | | | - Simone Marini
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (S.S.); (S.M.)
- Institute of Marine Sciences, National Research Council of Italy (CNR-ISMAR), 19032 La Spezia, Italy
| | - Giacomo Picardi
- Instituto de Ciencias del Mar (ICM)—CSIC, 08003 Barcelona, Spain; (N.J.R.); (D.C.); (G.P.)
| | - Bernard Foing
- Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081-1087, 1081 HV Amsterdam, The Netherlands;
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Li Q, Cheng X, Liu X, Gao P, Wang H, Su C, Huang Q. Ammonia-oxidizing archaea adapted better to the dark, alkaline oligotrophic karst cave than their bacterial counterparts. Front Microbiol 2024; 15:1377721. [PMID: 38659982 PMCID: PMC11041041 DOI: 10.3389/fmicb.2024.1377721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 03/28/2024] [Indexed: 04/26/2024] Open
Abstract
Subsurface karst caves provide unique opportunities to study the deep biosphere, shedding light on microbial contribution to elemental cycling. Although ammonia oxidation driven by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) is well explored in soil and marine environments, our understanding in the subsurface biosphere still remained limited to date. To address this gap, weathered rock and sediment samples were collected from the Xincuntun Cave in Guilin City, an alkaline karst cave, and subjected to high-throughput sequencing and quantification of bacterial and archaeal amoA, along with determination of the potential nitrification rates (PNR). Results revealed that AOA dominated in ammonia oxidation, contributing 48-100% to the PNR, and AOA amoA gene copies outnumbered AOB by 2 to 6 orders. Nitrososphaera dominated in AOA communities, while Nitrosopira dominated AOB communities. AOA demonstrated significantly larger niche breadth than AOB. The development of AOA communities was influenced by deterministic processes (50.71%), while AOB communities were predominantly influenced by stochastic processes. TOC, NH4+, and Cl- played crucial roles in shaping the compositions of ammonia oxidizers at the OTU level. Cross-domain co-occurrence networks highlighted the dominance of AOA nodes in the networks and positive associations between AOA and AOB, especially in the inner zone, suggesting collaborative effort to thrive in extreme environments. Their high gene copies, dominance in the interaction with ammonia oxidizing bacteria, expansive niche breadth and substantial contribution to PNR collectively confirmed that AOA better adapted to alkaline, oligotrophic karst caves environments, and thus play a fundamental role in nitrogen cycling in subsurface biosphere.
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Affiliation(s)
- Qing Li
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Xiaoyu Cheng
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Xiaoyan Liu
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Pengfei Gao
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Hongmei Wang
- School of Environmental Studies, China University of Geosciences, Wuhan, China
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Chuntian Su
- Institute of Karst Geology, CAGS/Key Laboratory of Karst Dynamics, MNR & GZAR, Guilin, China
- Pingguo Guangxi, Karst Ecosystem, National Observation and Research Station, Pingguo, Guangxi, China
| | - Qibo Huang
- Institute of Karst Geology, CAGS/Key Laboratory of Karst Dynamics, MNR & GZAR, Guilin, China
- Pingguo Guangxi, Karst Ecosystem, National Observation and Research Station, Pingguo, Guangxi, China
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Thweatt JL, Harman CE, Araújo MN, Marlow JJ, Oliver GC, Sabuda MC, Sevgen S, Wilpiszeki RL. Chapter 6: The Breadth and Limits of Life on Earth. ASTROBIOLOGY 2024; 24:S124-S142. [PMID: 38498824 DOI: 10.1089/ast.2021.0131] [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: 03/20/2024]
Abstract
Scientific ideas about the potential existence of life elsewhere in the universe are predominantly informed by knowledge about life on Earth. Over the past ∼4 billion years, life on Earth has evolved into millions of unique species. Life now inhabits nearly every environmental niche on Earth that has been explored. Despite the wide variety of species and diverse biochemistry of modern life, many features, such as energy production mechanisms and nutrient requirements, are conserved across the Tree of Life. Such conserved features help define the operational parameters required by life and therefore help direct the exploration and evaluation of habitability in extraterrestrial environments. As new diversity in the Tree of Life continues to expand, so do the known limits of life on Earth and the range of environments considered habitable elsewhere. The metabolic processes used by organisms living on the edge of habitability provide insights into the types of environments that would be most suitable to hosting extraterrestrial life, crucial for planning and developing future astrobiology missions. This chapter will introduce readers to the breadth and limits of life on Earth and show how the study of life at the extremes can inform the broader field of astrobiology.
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Affiliation(s)
- Jennifer L Thweatt
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA. (Former)
| | - C E Harman
- Planetary Systems Branch, NASA Ames Research Center, Moffett Field, California, USA
| | - M N Araújo
- Biochemistry Department, University of São Paulo, São Carlos, Brazil
| | - Jeffrey J Marlow
- Department of Biology, Boston University, Boston, Massachusetts, USA
| | - Gina C Oliver
- Department of Geology, San Bernardino Valley College, San Bernardino, California, USA
| | - Mary C Sabuda
- Department of Earth and Environmental Sciences, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA
- Biotechnology Institute, University of Minnesota-Twin Cities, St. Paul, Minnesota, USA
| | - Serhat Sevgen
- Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin, Turkey
- Blue Marble Space Institute of Science, Seattle, Washington, USA
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Chin KJ, Ünal B, Sanderson M, Aboderin F, Nüsslein K. Selective trace elements significantly enhanced methane production in coal bed methane systems by stimulating microbial activity. Microbiol Spectr 2024; 12:e0350823. [PMID: 38236038 PMCID: PMC10846109 DOI: 10.1128/spectrum.03508-23] [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: 10/02/2023] [Accepted: 10/17/2023] [Indexed: 01/19/2024] Open
Abstract
Trace elements are associated with the microbial degradation of organic matter and methanogenesis, as enzymes in metabolic pathways often employ trace elements as essential cofactors. However, only a few studies investigated the effects of trace elements on the metabolic activity of microbial communities associated with biogenic coalbed methane production. We aimed to determine the effects of strategically selected trace elements on structure and function of active bacterial and methanogenic communities to stimulate methane production in subsurface coalbeds. Microcosms were established with produced water and coal from coalbed methane wells located in the Powder River Basin, Wyoming, USA. In initial pilot experiments with eight different trace elements, individual amendments of Co, Cu, and Mo lead to significantly higher methane production. Transcript levels of mcrA, the key marker gene for methanogenesis, positively correlated with increased methane production. Phylogenetic analysis of the mcrA cDNA library demonstrated compositional shifts of the active methanogenic community and increase of their diversity, particularly of hydrogenotrophic methanogens. High-throughput sequencing of cDNA obtained from 16S rRNA demonstrated active and abundant bacterial groups in response to trace element amendments. Active Acetobacterium members increased in response to Co, Cu, and Mo additions. The findings of this study yield new insights into the importance of essential trace elements on the metabolic activity of microbial communities involved in subsurface coalbed methane and provide a better understanding of how microbial community composition is shaped by trace elements.IMPORTANCEMicrobial life in the deep subsurface of coal beds is limited by nutrient replenishment. While coal bed microbial communities are surrounded by carbon sources, we hypothesized that other nutrients such as trace elements needed as cofactors for enzymes are missing. Amendment of selected trace elements resulted in compositional shifts of the active methanogenic and bacterial communities and correlated with higher transcript levels of mcrA. The findings of this study yield new insights to not only identify possible limitations of microbes by replenishment of trace elements within their specific hydrological placement but also into the importance of essential trace elements for the metabolic activity of microbial communities involved in subsurface coalbed methane production and provides a better understanding of how microbial community composition is shaped by trace elements. Furthermore, this finding might help to revive already spent coal bed methane well systems with the ultimate goal to stimulate methane production.
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Affiliation(s)
- Kuk-Jeong Chin
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Burcu Ünal
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
- Department of Environmental Engineering, RheinMain University of Applied Sciences, Wiesbaden, Germany
| | - Michael Sanderson
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Feranmi Aboderin
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Klaus Nüsslein
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, USA
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5
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Thompson J, Barr C, Babcock-Adams L, Bird L, La Cava E, Garber A, Hongoh Y, Liu M, Nealson KH, Okamoto A, Repeta D, Suzuki S, Tacto C, Tashjian M, Merino N. Insights into the physiological and genomic characterization of three bacterial isolates from a highly alkaline, terrestrial serpentinizing system. Front Microbiol 2023; 14:1179857. [PMID: 37520355 PMCID: PMC10373932 DOI: 10.3389/fmicb.2023.1179857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/23/2023] [Indexed: 08/01/2023] Open
Abstract
The terrestrial serpentinite-hosted ecosystem known as "The Cedars" is home to a diverse microbial community persisting under highly alkaline (pH ~ 12) and reducing (Eh < -550 mV) conditions. This extreme environment presents particular difficulties for microbial life, and efforts to isolate microorganisms from The Cedars over the past decade have remained challenging. Herein, we report the initial physiological assessment and/or full genomic characterization of three isolates: Paenibacillus sp. Cedars ('Paeni-Cedars'), Alishewanella sp. BS5-314 ('Ali-BS5-314'), and Anaerobacillus sp. CMMVII ('Anaero-CMMVII'). Paeni-Cedars is a Gram-positive, rod-shaped, mesophilic facultative anaerobe that grows between pH 7-10 (minimum pH tested was 7), temperatures 20-40°C, and 0-3% NaCl concentration. The addition of 10-20 mM CaCl2 enhanced growth, and iron reduction was observed in the following order, 2-line ferrihydrite > magnetite > serpentinite ~ chromite ~ hematite. Genome analysis identified genes for flavin-mediated iron reduction and synthesis of a bacillibactin-like, catechol-type siderophore. Ali-BS5-314 is a Gram-negative, rod-shaped, mesophilic, facultative anaerobic alkaliphile that grows between pH 10-12 and temperatures 10-40°C, with limited growth observed 1-5% NaCl. Nitrate is used as a terminal electron acceptor under anaerobic conditions, which was corroborated by genome analysis. The Ali-BS5-314 genome also includes genes for benzoate-like compound metabolism. Anaero-CMMVII remained difficult to cultivate for physiological studies; however, growth was observed between pH 9-12, with the addition of 0.01-1% yeast extract. Anaero-CMMVII is a probable oxygen-tolerant anaerobic alkaliphile with hydrogenotrophic respiration coupled with nitrate reduction, as determined by genome analysis. Based on single-copy genes, ANI, AAI and dDDH analyses, Paeni-Cedars and Ali-BS5-314 are related to other species (P. glucanolyticus and A. aestuarii, respectively), and Anaero-CMMVII represents a new species. The characterization of these three isolates demonstrate the range of ecophysiological adaptations and metabolisms present in serpentinite-hosted ecosystems, including mineral reduction, alkaliphily, and siderophore production.
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Affiliation(s)
- Jaclyn Thompson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Casey Barr
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Lydia Babcock-Adams
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Lina Bird
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC, United States
| | - Eugenio La Cava
- National Institute for Materials Science, Tsukuba, Ibaraki, Japan
| | - Arkadiy Garber
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, United States
| | - Yuichi Hongoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Mark Liu
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Kenneth H. Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Akihiro Okamoto
- Research Center for Macromolecules and Biomaterials, National Institute for Materials Science, Tsukuba, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Japan
| | - Daniel Repeta
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Shino Suzuki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Sagamihara, Kanagawa, Japan
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), JAMSTEC, Yokosuka, Kanagawa, Japan
| | - Clarissa Tacto
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Michelle Tashjian
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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6
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Najjari A, Boussetta A, Youssef N, Linares-Pastén JA, Mahjoubi M, Belloum R, Sghaier H, Cherif A, Ouzari HI. Physiological and genomic insights into abiotic stress of halophilic archaeon Natrinema altunense 4.1R isolated from a saline ecosystem of Tunisian desert. Genetica 2023; 151:133-152. [PMID: 36795306 PMCID: PMC9995536 DOI: 10.1007/s10709-023-00182-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 02/02/2023] [Indexed: 02/17/2023]
Abstract
Halophilic archaea are polyextremophiles with the ability to withstand fluctuations in salinity, high levels of ultraviolet radiation, and oxidative stress, allowing them to survive in a wide range of environments and making them an excellent model for astrobiological research. Natrinema altunense 4.1R is a halophilic archaeon isolated from the endorheic saline lake systems, Sebkhas, located in arid and semi-arid regions of Tunisia. It is an ecosystem characterized by periodic flooding from subsurface groundwater and fluctuating salinities. Here, we assess the physiological responses and genomic characterization of N. altunense 4.1R to UV-C radiation, as well as osmotic and oxidative stresses. Results showed that the 4.1R strain is able to survive up to 36% of salinity, up to 180 J/m2 to UV-C radiation, and at 50 mM of H2O2, a resistance profile similar to Halobacterium salinarum, a strain often used as UV-C resistant model. In order to understand the genetic determinants of N. altunense 4.1R survival strategy, we sequenced and analyzed its genome. Results showed multiple gene copies of osmotic stress, oxidative stress, and DNA repair response mechanisms supporting its survivability at extreme salinities and radiations. Indeed, the 3D molecular structures of seven proteins related to responses to UV-C radiation (excinucleases UvrA, UvrB, and UvrC, and photolyase), saline stress (trehalose-6-phosphate synthase OtsA and trehalose-phosphatase OtsB), and oxidative stress (superoxide dismutase SOD) were constructed by homology modeling. This study extends the abiotic stress range for the species N. altunense and adds to the repertoire of UV and oxidative stress resistance genes generally known from haloarchaeon.
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Affiliation(s)
- Afef Najjari
- Faculté des Sciences de Tunis, LR03ES03 Laboratoire de Microbiologie et Biomolécules Actives, Université Tunis El Manar, 2092, Tunis, Tunisie
| | - Ayoub Boussetta
- Faculté des Sciences de Tunis, LR03ES03 Laboratoire de Microbiologie et Biomolécules Actives, Université Tunis El Manar, 2092, Tunis, Tunisie
| | - Noha Youssef
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Javier A Linares-Pastén
- Department of Biotechnology, Faculty of Engineering, Lunds Tekniska Högskola (LTH), Lund University, P. O. Box 124, 22100, Lund, Sweden.
| | - Mouna Mahjoubi
- University of Manouba, ISBST, LR11-ES31 BVBGR, Biotechpole Sidi Thabet, 2020, Ariana, Tunisia
| | - Rahma Belloum
- Faculté des Sciences de Tunis, LR03ES03 Laboratoire de Microbiologie et Biomolécules Actives, Université Tunis El Manar, 2092, Tunis, Tunisie
| | - Haitham Sghaier
- Laboratory "Energy and Matter for Development of Nuclear Sciences" (LR16CNSTN02), National Center for Nuclear Sciences and Technology (CNSTN), Ariana, Tunisia
| | - Ameur Cherif
- University of Manouba, ISBST, LR11-ES31 BVBGR, Biotechpole Sidi Thabet, 2020, Ariana, Tunisia
| | - Hadda Imene Ouzari
- Faculté des Sciences de Tunis, LR03ES03 Laboratoire de Microbiologie et Biomolécules Actives, Université Tunis El Manar, 2092, Tunis, Tunisie
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Rempfert KR, Nothaft DB, Kraus EA, Asamoto CK, Evans RD, Spear JR, Matter JM, Kopf SH, Templeton AS. Subsurface biogeochemical cycling of nitrogen in the actively serpentinizing Samail Ophiolite, Oman. Front Microbiol 2023; 14:1139633. [PMID: 37152731 PMCID: PMC10160414 DOI: 10.3389/fmicb.2023.1139633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 03/15/2023] [Indexed: 05/09/2023] Open
Abstract
Nitrogen (N) is an essential element for life. N compounds such as ammonium ( NH 4 + ) may act as electron donors, while nitrate ( NO 3 - ) and nitrite ( NO 2 - ) may serve as electron acceptors to support energy metabolism. However, little is known regarding the availability and forms of N in subsurface ecosystems, particularly in serpentinite-hosted settings where hydrogen (H2) generated through water-rock reactions promotes habitable conditions for microbial life. Here, we analyzed N and oxygen (O) isotope composition to investigate the source, abundance, and cycling of N species within the Samail Ophiolite of Oman. The dominant dissolved N species was dependent on the fluid type, with Mg2+- HCO 3 - type fluids comprised mostly of NO 3 - , and Ca2+-OH- fluids comprised primarily of ammonia (NH3). We infer that fixed N is introduced to the serpentinite aquifer as NO 3 - . High concentrations of NO 3 - (>100 μM) with a relict meteoric oxygen isotopic composition (δ18O ~ 22‰, Δ17O ~ 6‰) were observed in shallow aquifer fluids, indicative of NO 3 - sourced from atmospheric deposition (rainwater NO 3 - : δ18O of 53.7‰, Δ17O of 16.8‰) mixed with NO 3 - produced in situ through nitrification (estimated endmember δ18O and Δ17O of ~0‰). Conversely, highly reacted hyperalkaline fluids had high concentrations of NH3 (>100 μM) with little NO 3 - detectable. We interpret that NH3 in hyperalkaline fluids is a product of NO 3 - reduction. The proportionality of the O and N isotope fractionation (18ε / 15ε) measured in Samail Ophiolite NO 3 - was close to unity (18ε / 15ε ~ 1), which is consistent with dissimilatory NO 3 - reduction with a membrane-bound reductase (NarG); however, abiotic reduction processes may also be occurring. The presence of genes commonly involved in N reduction processes (narG, napA, nrfA) in the metagenomes of biomass sourced from aquifer fluids supports potential biological involvement in the consumption of NO 3 - . Production of NH 4 + as the end-product of NO 3 - reduction via dissimilatory nitrate reduction to ammonium (DNRA) could retain N in the subsurface and fuel nitrification in the oxygenated near surface. Elevated bioavailable N in all sampled fluids indicates that N is not likely limiting as a nutrient in serpentinites of the Samail Ophiolite.
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Affiliation(s)
- Kaitlin R. Rempfert
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
- *Correspondence: Kaitlin R. Rempfert
| | - Daniel B. Nothaft
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - Emily A. Kraus
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
| | - Ciara K. Asamoto
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - R. Dave Evans
- School of Biological Sciences, Washington State University, Pullman, WA, United States
| | - John R. Spear
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
- Quantitative Biosciences and Engineering, Colorado School of Mines, Golden, CO, United States
| | - Juerg M. Matter
- National Oceanography Centre, University of Southampton, Southampton, United Kingdom
| | - Sebastian H. Kopf
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - Alexis S. Templeton
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
- Alexis S. Templeton
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8
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Coleine C, Delgado-Baquerizo M. Unearthing terrestrial extreme microbiomes for searching terrestrial-like life in the Solar System. Trends Microbiol 2022; 30:1101-1115. [PMID: 35568658 DOI: 10.1016/j.tim.2022.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/03/2022] [Accepted: 04/11/2022] [Indexed: 01/13/2023]
Abstract
The possibility of life elsewhere in the universe has fascinated humankind for ages. To the best of our knowledge, life, as we know it, is limited to planet Earth; yet current investigation suggests that life might be more common than previously thought. In this review, we explore extreme terrestrial analogue environments in the search for some notable examples of extreme organisms, including overlooked microbial groups such as viruses, fungi, and protists, associated with limits of life on Earth. This knowledge is integral to provide the foundational principles needed to predict what sort of Earth-like organisms we might find in the Solar System and beyond, and to understand the future and origins of life on Earth.
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Affiliation(s)
- Claudia Coleine
- Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy.
| | - Manuel Delgado-Baquerizo
- Laboratorio de Biodiversidad y Funcionamiento Ecosistémico. Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Av. Reina Mercedes 10, E-41012, Sevilla, Spain; Unidad Asociada CSIC-UPO (BioFun). Universidad Pablo de Olavide, 41013 Sevilla, Spain.
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Abstract
Alkaline fluids venting from chimneys of the Lost City hydrothermal field flow from a potentially vast microbial habitat within the seafloor where energy and organic molecules are released by chemical reactions within rocks uplifted from Earth's mantle. In this study, we investigated hydrothermal fluids venting from Lost City chimneys as windows into subseafloor environments where the products of geochemical reactions, such as molecular hydrogen (H2), formate, and methane, may be the only available sources of energy for biological activity. Our deep sequencing of metagenomes and metatranscriptomes from these hydrothermal fluids revealed a few key species of archaea and bacteria that are likely to play critical roles in the subseafloor microbial ecosystem. We identified a population of Thermodesulfovibrionales (belonging to phylum Nitrospirota) as a prevalent sulfate-reducing bacterium that may be responsible for much of the consumption of H2 and sulfate in Lost City fluids. Metagenome-assembled genomes (MAGs) classified as Methanosarcinaceae and Candidatus Bipolaricaulota were also recovered from venting fluids and represent potential methanogenic and acetogenic members of the subseafloor ecosystem. These genomes share novel hydrogenases and formate dehydrogenase-like sequences that may be unique to hydrothermal environments where H2 and formate are much more abundant than carbon dioxide. The results of this study include multiple examples of metabolic strategies that appear to be advantageous in hydrothermal and subsurface alkaline environments where energy and carbon are provided by geochemical reactions. IMPORTANCE The Lost City hydrothermal field is an iconic example of a microbial ecosystem fueled by energy and carbon from Earth's mantle. Uplift of mantle rocks into the seafloor can trigger a process known as serpentinization that releases molecular hydrogen (H2) and creates unusual environmental conditions where simple organic carbon molecules are more stable than dissolved inorganic carbon. This study provides an initial glimpse into the kinds of microbes that live deep within the seafloor where serpentinization takes place, by sampling hydrothermal fluids exiting from the Lost City chimneys. The metabolic strategies that these microbes appear to be using are also shared by microbes that inhabit other sites of serpentinization, including continental subsurface environments and natural springs. Therefore, the results of this study contribute to a broader, interdisciplinary effort to understand the general principles and mechanisms by which serpentinization-associated processes can support life on Earth and perhaps other worlds.
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10
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McClain CR, Bryant SR, Hanks G, Bowles MW. Extremophiles in Earth's Deep Seas: A View Toward Life in Exo-Oceans. ASTROBIOLOGY 2022; 22:1009-1028. [PMID: 35549348 DOI: 10.1089/ast.2021.0120] [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: 06/15/2023]
Abstract
Humanity's search for extraterrestrial life is a modern manifestation of the exploratory and curious nature that has led us through millennia of scientific discoveries. With the ongoing exploration of extraterrestrial bodies, the potential for discovery of extraterrestrial life has expanded. We may better inform this search through an understanding of how life persists and flourishes on Earth in a myriad of environmental extremes. A significant proportion of our knowledge of extremophiles on Earth comes from studies on deep ocean life. Here, we review and synthesize the range of environmental extremes observed in the deep sea, the life that persists in these extreme conditions, and the biological adaptations utilized by these remarkable life-forms. We also review confirmed and predicted extraterrestrial oceans in our solar system and propose deep-sea sites that may serve as planetary field analog environments. We show that the clever ingenuity of evolution under deep-sea conditions suggests that the plausibility of extraterrestrial life is much greater than previously thought.
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Affiliation(s)
- Craig R McClain
- Louisiana Universities Marine Consortium, Chauvin, Louisiana, USA
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - S River Bryant
- Louisiana Universities Marine Consortium, Chauvin, Louisiana, USA
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Granger Hanks
- Louisiana Universities Marine Consortium, Chauvin, Louisiana, USA
- Department of Biology, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
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11
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Microbial Diversity and Function in Shallow Subsurface Sediment and Oceanic Lithosphere of the Atlantis Massif. mBio 2021; 12:e0049021. [PMID: 34340550 PMCID: PMC8406227 DOI: 10.1128/mbio.00490-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The marine lithospheric subsurface is one of the largest biospheres on Earth; however, little is known about the identity and ecological function of microorganisms found in low abundance in this habitat, though these organisms impact global-scale biogeochemical cycling. Here, we describe the diversity and metabolic potential of sediment and endolithic (within rock) microbial communities found in ultrasmall amounts (101 to 104 cells cm−3) in the subsurface of the Atlantis Massif, an oceanic core complex on the Mid-Atlantic Ridge that was sampled on International Ocean Discovery Program (IODP) Expedition 357. This study used fluorescence-activated cell sorting (FACS) to enable the first amplicon, metagenomic, and single-cell genomic study of the shallow (<20 m below seafloor) subsurface of an actively serpentinizing marine system. The shallow subsurface biosphere of the Atlantis Massif was found to be distinct from communities observed in the nearby Lost City alkaline hydrothermal fluids and chimneys, yet similar to other low-temperature, aerobic subsurface settings. Genes associated with autotrophy were rare, although heterotrophy and aerobic carbon monoxide and formate cycling metabolisms were identified. Overall, this study reveals that the shallow subsurface of an oceanic core complex hosts a biosphere that is not fueled by active serpentinization reactions and by-products.
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12
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Kevorkian RT, Callahan S, Winstead R, Lloyd KG. ANME-1 archaea may drive methane accumulation and removal in estuarine sediments. ENVIRONMENTAL MICROBIOLOGY REPORTS 2021; 13:185-194. [PMID: 33462984 DOI: 10.1111/1758-2229.12926] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
ANME-1 archaea subsist on the very low energy of anaerobic oxidation of methane (AOM). Most marine sediments shift from net AOM in the sulfate methane transition zone (SMTZ) to methanogenesis in the methane zone (MZ) below it. In White Oak River estuarine sediments, ANME-1 comprised 99.5% of 16S rRNA genes from amplicons and 100% of 16S rRNA genes from metagenomes of the Methanomicrobia in the SMTZ and 99.9% and 98.3%, respectively, in the MZ. Each of the 16 ANME-1 OTUs (97% similarity) had peaks in the SMTZ that coincided with peaks of putative sulfate-reducing bacteria Desulfatiglans sp. and SEEP-SRB1. In the MZ, ANME-1, but none of the putative sulfate-reducing bacteria or cultured methanogens, increased with depth. Our meta-analysis of public data showed only ANME-1 expressed methanogenic genes during both net AOM and net methanogenesis in an enrichment culture. We conclude that ANME-1 perform AOM in the SMTZ and methanogenesis in the MZ of White Oak River sediments. This metabolic flexibility may expand habitable zones in extraterrestrial environments, since it enables greater energy yields in a fluctuating energetic landscape.
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Affiliation(s)
| | - Sean Callahan
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Rachel Winstead
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Karen G Lloyd
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
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13
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Murphy TR, Xiao R, Hamilton-Brehm SD. Hybrid genome de novo assembly with methylome analysis of the anaerobic thermophilic subsurface bacterium Thermanaerosceptrum fracticalcis strain DRI-13 T. BMC Genomics 2021; 22:209. [PMID: 33757423 PMCID: PMC7988955 DOI: 10.1186/s12864-021-07535-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/15/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND There is a dearth of sequenced and closed microbial genomes from environments that exceed > 500 m below level terrestrial surface. Coupled with even fewer cultured isolates, study and understanding of how life endures in the extreme oligotrophic subsurface environments is greatly hindered. Using a de novo hybrid assembly of Illumina and Oxford Nanopore sequences we produced a circular genome with corresponding methylome profile of the recently characterized thermophilic, anaerobic, and fumarate-respiring subsurface bacterium, Thermanaerosceptrum fracticalcis, strain DRI-13T to understand how this microorganism survives the deep subsurface. RESULTS The hybrid assembly produced a single circular genome of 3.8 Mb in length with an overall GC content of 45%. Out of the total 4022 annotated genes, 3884 are protein coding, 87 are RNA encoding genes, and the remaining 51 genes were associated with regulatory features of the genome including riboswitches and T-box leader sequences. Approximately 24% of the protein coding genes were hypothetical. Analysis of strain DRI-13T genome revealed: 1) energy conservation by bifurcation hydrogenase when growing on fumarate, 2) four novel bacterial prophages, 3) methylation profile including 76.4% N6-methyladenine and 3.81% 5-methylcytosine corresponding to novel DNA methyltransferase motifs. As well a cluster of 45 genes of unknown protein families that have enriched DNA mCpG proximal to the transcription start sites, and 4) discovery of a putative core of bacteriophage exclusion (BREX) genes surrounded by hypothetical proteins, with predicted functions as helicases, nucleases, and exonucleases. CONCLUSIONS The de novo hybrid assembly of strain DRI-13T genome has provided a more contiguous and accurate view of the subsurface bacterium T. fracticalcis, strain DRI-13T. This genome analysis reveals a physiological focus supporting syntrophy, non-homologous double stranded DNA repair, mobility/adherence/chemotaxis, unique methylome profile/recognized motifs, and a BREX defense system. The key to microbial subsurface survival may not rest on genetic diversity, but rather through specific syntrophy niches and novel methylation strategies.
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Affiliation(s)
- Trevor R Murphy
- Department of Microbiology, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Rui Xiao
- Department of Microbiology, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Scott D Hamilton-Brehm
- Department of Microbiology, Southern Illinois University Carbondale, Carbondale, IL, USA.
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14
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Abstract
Most definitions of life assume that, at a minimum, life is a physical form of matter distinct from its environment at a lower state of entropy than its surroundings, using energy from the environment for internal maintenance and activity, and capable of autonomous reproduction. These assumptions cover all of life as we know it, though more exotic entities can be envisioned, including organic forms with novel biochemistries, dynamic inorganic matter, and self-replicating machines. The probability that any particular form of life will be found on another planetary body depends on the nature and history of that alien world. So the biospheres would likely be very different on a rocky planet with an ice-covered global ocean, a barren planet devoid of surface liquid, a frigid world with abundant liquid hydrocarbons, on a rogue planet independent of a host star, on a tidally locked planet, on super-Earths, or in long-lived clouds in dense atmospheres. While life at least in microbial form is probably pervasive if rare throughout the Universe, and technologically advanced life is likely much rarer, the chance that an alternative form of life, though not intelligent life, could exist and be detected within our Solar System is a distinct possibility.
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15
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Carrier B, Beaty D, Meyer M, Blank J, Chou L, DasSarma S, Des Marais D, Eigenbrode J, Grefenstette N, Lanza N, Schuerger A, Schwendner P, Smith H, Stoker C, Tarnas J, Webster K, Bakermans C, Baxter B, Bell M, Benner S, Bolivar Torres H, Boston P, Bruner R, Clark B, DasSarma P, Engelhart A, Gallegos Z, Garvin Z, Gasda P, Green J, Harris R, Hoffman M, Kieft T, Koeppel A, Lee P, Li X, Lynch K, Mackelprang R, Mahaffy P, Matthies L, Nellessen M, Newsom H, Northup D, O'Connor B, Perl S, Quinn R, Rowe L, Sauterey B, Schneegurt M, Schulze-Makuch D, Scuderi L, Spilde M, Stamenković V, Torres Celis J, Viola D, Wade B, Walker C, Wiens R, Williams A, Williams J, Xu J. Mars Extant Life: What's Next? Conference Report. ASTROBIOLOGY 2020; 20:785-814. [PMID: 32466662 PMCID: PMC7307687 DOI: 10.1089/ast.2020.2237] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/24/2020] [Indexed: 05/19/2023]
Abstract
On November 5-8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The conference gathered a community of actively publishing experts in disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset of conference attendees concluded that there is a realistic possibility that Mars hosts indigenous microbial life. A powerful theme that permeated the conference is that the key to the search for martian extant life lies in identifying and exploring refugia ("oases"), where conditions are either permanently or episodically significantly more hospitable than average. Based on our existing knowledge of Mars, conference participants highlighted four potential martian refugium (not listed in priority order): Caves, Deep Subsurface, Ices, and Salts. The conference group did not attempt to reach a consensus prioritization of these candidate environments, but instead felt that a defensible prioritization would require a future competitive process. Within the context of these candidate environments, we identified a variety of geological search strategies that could narrow the search space. Additionally, we summarized a number of measurement techniques that could be used to detect evidence of extant life (if present). Again, it was not within the scope of the conference to prioritize these measurement techniques-that is best left for the competitive process. We specifically note that the number and sensitivity of detection methods that could be implemented if samples were returned to Earth greatly exceed the methodologies that could be used at Mars. Finally, important lessons to guide extant life search processes can be derived both from experiments carried out in terrestrial laboratories and analog field sites and from theoretical modeling.
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Affiliation(s)
- B.L. Carrier
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - D.W. Beaty
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | - J.G. Blank
- NASA Ames Research Center, Moffett Field, California, USA
- Blue Marble Space Institute of Science, Seattle, Washington, USA
| | - L. Chou
- Georgetown University, Washington, DC, USA
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - S. DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | | | | | - N.L. Lanza
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - A.C. Schuerger
- University of Florida/Space Life Sciences Laboratory, Kennedy Space Center, Florida, USA
| | - P. Schwendner
- University of Florida/Space Life Sciences Laboratory, Kennedy Space Center, Florida, USA
| | - H.D. Smith
- NASA Ames Research Center, Moffett Field, California, USA
| | - C.R. Stoker
- NASA Ames Research Center, Moffett Field, California, USA
| | - J.D. Tarnas
- Brown University, Providence, Rhode Island, USA
| | - K.D. Webster
- Planetary Science Institute, Tucson, Arizona, USA
| | - C. Bakermans
- Pennsylvania State University, Altoona, Pennsylvania, USA
| | - B.K. Baxter
- Westminster College, Salt Lake City, Utah, USA
| | - M.S. Bell
- NASA Johnson Space Center, Houston, Texas, USA
| | - S.A. Benner
- Foundation for Applied Molecular Evolution, Alachua, Florida, USA
| | - H.H. Bolivar Torres
- Universidad Nacional Autonoma de Mexico, Coyoacan, Distrito Federal Mexico, Mexico
| | - P.J. Boston
- NASA Astrobiology Institute, NASA Ames Research Center, Moffett Field, California, USA
| | - R. Bruner
- Denver Museum of Nature and Science, Denver, Colorado, USA
| | - B.C. Clark
- Space Science Institute, Littleton, Colorado, USA
| | - P. DasSarma
- Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Z.E. Gallegos
- University of New Mexico, Albuquerque, New Mexico, USA
| | - Z.K. Garvin
- Princeton University, Princeton, New Jersey, USA
| | - P.J. Gasda
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - J.H. Green
- Texas Tech University, Lubbock, Texas, USA
| | - R.L. Harris
- Princeton University, Princeton, New Jersey, USA
| | - M.E. Hoffman
- University of New Mexico, Albuquerque, New Mexico, USA
| | - T. Kieft
- New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA
| | | | - P.A. Lee
- College of Charleston, Charleston, South Carolina, USA
| | - X. Li
- University of Maryland Baltimore County, Baltimore, Maryland, USA
| | - K.L. Lynch
- Lunar and Planetary Institute/USRA, Houston, Texas, USA
| | - R. Mackelprang
- California State University Northridge, Northridge, California, USA
| | - P.R. Mahaffy
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - L.H. Matthies
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | - H.E. Newsom
- University of New Mexico, Albuquerque, New Mexico, USA
| | - D.E. Northup
- University of New Mexico, Albuquerque, New Mexico, USA
| | | | - S.M. Perl
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - R.C. Quinn
- NASA Ames Research Center, Moffett Field, California, USA
| | - L.A. Rowe
- Valparaiso University, Valparaiso, Indiana, USA
| | | | | | | | - L.A. Scuderi
- University of New Mexico, Albuquerque, New Mexico, USA
| | - M.N. Spilde
- University of New Mexico, Albuquerque, New Mexico, USA
| | - V. Stamenković
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - J.A. Torres Celis
- Universidad Nacional Autonoma de Mexico, Coyoacan, Distrito Federal Mexico, Mexico
| | - D. Viola
- NASA Ames Research Center, Moffett Field, California, USA
| | - B.D. Wade
- Michigan State University, East Lansing, Michigan, USA
| | - C.J. Walker
- Delaware State University, Dover, Delaware, USA
| | - R.C. Wiens
- Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | | | - J.M. Williams
- University of New Mexico, Albuquerque, New Mexico, USA
| | - J. Xu
- University of Texas, El Paso, Texas, USA
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16
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Purkamo L, Kietäväinen R, Nuppunen-Puputti M, Bomberg M, Cousins C. Ultradeep Microbial Communities at 4.4 km within Crystalline Bedrock: Implications for Habitability in a Planetary Context. Life (Basel) 2020; 10:E2. [PMID: 31947979 PMCID: PMC7175195 DOI: 10.3390/life10010002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/31/2019] [Accepted: 01/01/2020] [Indexed: 01/06/2023] Open
Abstract
The deep bedrock surroundings are an analog for extraterrestrial habitats for life. In this study, we investigated microbial life within anoxic ultradeep boreholes in Precambrian bedrock, including the adaptation to environmental conditions and lifestyle of these organisms. Samples were collected from Pyhäsalmi mine environment in central Finland and from geothermal drilling wells in Otaniemi, Espoo, in southern Finland. Microbial communities inhabiting the up to 4.4 km deep bedrock were characterized with phylogenetic marker gene (16S rRNA genes and fungal ITS region) amplicon and DNA and cDNA metagenomic sequencing. Functional marker genes (dsrB, mcrA, narG) were quantified with qPCR. Results showed that although crystalline bedrock provides very limited substrates for life, the microbial communities are diverse. Gammaproteobacterial phylotypes were most dominant in both studied sites. Alkanindiges -affiliating OTU was dominating in Pyhäsalmi fluids, while different depths of Otaniemi samples were dominated by Pseudomonas. One of the most common OTUs detected from Otaniemi could only be classified to phylum level, highlighting the uncharacterized nature of the deep biosphere in bedrock. Chemoheterotrophy, fermentation and nitrogen cycling are potentially significant metabolisms in these ultradeep environments. To conclude, this study provides information on microbial ecology of low biomass, carbon-depleted and energy-deprived deep subsurface environment. This information is useful in the prospect of finding life in other planetary bodies.
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Affiliation(s)
- Lotta Purkamo
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews KY16 9AL, UK
- Geological Survey of Finland, 02151 Espoo, Finland
| | - Riikka Kietäväinen
- Geological Survey of Finland, 02151 Espoo, Finland
- Department of Geosciences and Geography, University of Helsinki, 00014 Helsinki, Finland
| | | | - Malin Bomberg
- VTT Technical Research Centre of Finland, 02044 VTT, Finland
| | - Claire Cousins
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews KY16 9AL, UK
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17
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Haqq-Misra J. Does the Evolution of Complex Life Depend on the Stellar Spectral Energy Distribution? ASTROBIOLOGY 2019; 19:1292-1299. [PMID: 31429585 DOI: 10.1089/ast.2018.1946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This article presents the proportional evolutionary time (PET) hypothesis, which posits that the mean time required for the evolution of complex life is a function of stellar mass. The "biological available window" is defined as the region of a stellar spectrum between 200 and 1200 nm that generates free energy for life. Over the ∼4 Gyr history of Earth, the total energy incident at the top of the atmosphere and within the biological available window is ∼1034 J. The hypothesis assumes that the rate of evolution from the origin of life to complex life is proportional to this total energy, which would suggest that planets orbiting other stars should not show signs of complex life if the total energy incident on the planet is below this energy threshold. The PET hypothesis predicts that late K- and M-dwarf stars (M < 0.7 [Formula: see text]) are too young to host any complex life at the present age of the Universe. F-, G-, and early K-dwarf stars (M > 0.7 [Formula: see text]) represent the best targets for the next generation of space telescopes to search for spectroscopic biosignatures indicative of complex life.
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18
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Merino N, Aronson HS, Bojanova DP, Feyhl-Buska J, Wong ML, Zhang S, Giovannelli D. Corrigendum: Living at the Extremes: Extremophiles and the Limits of Life in a Planetary Context. Front Microbiol 2019; 10:1785. [PMID: 31456760 PMCID: PMC6700686 DOI: 10.3389/fmicb.2019.01785] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 07/18/2019] [Indexed: 11/27/2022] Open
Affiliation(s)
- Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States.,Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.,Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Lab, Livermore, CA, United States
| | - Heidi S Aronson
- Department of Biology, University of Southern California, Los Angeles, CA, United States
| | - Diana P Bojanova
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Jayme Feyhl-Buska
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Michael L Wong
- Department of Astronomy - Astrobiology Program, University of Washington, Seattle, WA, United States.,NASA Astrobiology Institute's Virtual Planetary Laboratory, University of Washington, Seattle, WA, United States
| | - Shu Zhang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, CA, United States
| | - Donato Giovannelli
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.,Department of Biology, University of Naples "Federico II", Naples, Italy.,Department of Marine and Coastal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States.,Institute for Biological Resources and Marine Biotechnology, National Research Council of Italy, Ancona, Italy
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19
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Merino N, Aronson HS, Bojanova DP, Feyhl-Buska J, Wong ML, Zhang S, Giovannelli D. Living at the Extremes: Extremophiles and the Limits of Life in a Planetary Context. Front Microbiol 2019; 10:780. [PMID: 31037068 PMCID: PMC6476344 DOI: 10.3389/fmicb.2019.00780] [Citation(s) in RCA: 198] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/27/2019] [Indexed: 01/21/2023] Open
Abstract
Prokaryotic life has dominated most of the evolutionary history of our planet, evolving to occupy virtually all available environmental niches. Extremophiles, especially those thriving under multiple extremes, represent a key area of research for multiple disciplines, spanning from the study of adaptations to harsh conditions, to the biogeochemical cycling of elements. Extremophile research also has implications for origin of life studies and the search for life on other planetary and celestial bodies. In this article, we will review the current state of knowledge for the biospace in which life operates on Earth and will discuss it in a planetary context, highlighting knowledge gaps and areas of opportunity.
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Affiliation(s)
- Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States.,Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.,Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Lab, Livermore, CA, United States
| | - Heidi S Aronson
- Department of Biology, University of Southern California, Los Angeles, CA, United States
| | - Diana P Bojanova
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Jayme Feyhl-Buska
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Michael L Wong
- Department of Astronomy - Astrobiology Program, University of Washington, Seattle, WA, United States.,NASA Astrobiology Institute's Virtual Planetary Laboratory, University of Washington, Seattle, WA, United States
| | - Shu Zhang
- Section of Infection and Immunity, Herman Ostrow School of Dentistry of USC, University of Southern California, Los Angeles, CA, United States
| | - Donato Giovannelli
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.,Department of Biology, University of Naples "Federico II", Naples, Italy.,Department of Marine and Coastal Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States.,Institute for Biological Resources and Marine Biotechnology, National Research Council of Italy, Ancona, Italy
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