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Maggiori C, Fernández-Martínez MA, Bourdages LJ, Sánchez-García L, Moreno-Paz M, Sobrado JM, Carrizo D, Vicente-Retortillo Á, Goordial J, Whyte LG. Biosignature Detection and MinION Sequencing of Antarctic Cryptoendoliths After Exposure to Mars Simulation Conditions. ASTROBIOLOGY 2024; 24:44-60. [PMID: 38153386 DOI: 10.1089/ast.2023.0025] [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: 12/29/2023]
Abstract
In the search for life in our Solar System, Mars remains a promising target based on its proximity and similarity to Earth. When Mars transitioned from a warmer, wetter climate to its current dry and freezing conditions, any putative extant life probably retreated into habitable refugia such as the subsurface or the interior of rocks. Terrestrial cryptoendolithic microorganisms (i.e., those inhabiting rock interiors) thus represent possible modern-day Mars analogs, particularly those from the hyperarid McMurdo Dry Valleys in Antarctica. As DNA is a strong definitive biosignature, given that there is no known abiotic chemistry that can polymerize nucleobases, we investigated DNA detection with MinION sequencing in Antarctic cryptoendoliths after an ∼58-sol exposure in MARTE, a Mars environmental chamber capable of simulating martian temperature, pressure, humidity, ultraviolet (UV) radiation, and atmospheric composition, in conjunction with protein and lipid detection. The MARTE conditions resulted in changes in community composition and DNA, proteins, and cell membrane-derived lipids remained detectable postexposure. Of the multitude of extreme environmental conditions on Mars, UV radiation (specifically UVC) is the most destructive to both cells and DNA. As such, we further investigated if a UVC exposure corresponding to ∼278 martian years would impede DNA detection via MinION sequencing. The MinION was able to successfully detect and sequence DNA after this UVC radiation exposure, suggesting its utility for life detection in future astrobiology missions focused on finding relatively recently exposed biomarkers inside possible martian refugia.
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Affiliation(s)
- Catherine Maggiori
- Department of Biology, Georgetown University, Washington, District of Columbia, USA
| | - Miguel Angel Fernández-Martínez
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Ste. Anne-de-Bellevue, Quebec, Canada
- Department of Ecology, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid, Spain
| | - Louis-Jacques Bourdages
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Ste. Anne-de-Bellevue, Quebec, Canada
| | | | | | | | | | | | - Jacqueline Goordial
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Lyle G Whyte
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Ste. Anne-de-Bellevue, Quebec, Canada
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Stoppiello GA, Coleine C, Moeller R, Ripa C, Billi D, Selbmann L. Seasonality Is the Main Determinant of Microbial Diversity Associated to Snow/Ice around Concordia Station on the Antarctic Polar Plateau. BIOLOGY 2023; 12:1193. [PMID: 37759592 PMCID: PMC10525097 DOI: 10.3390/biology12091193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/21/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
The French-Italian Concordia Research Station, situated on the Antarctic Polar Plateau at an elevation of 3233 m above sea level, offers a unique opportunity to study the presence and variation of microbes introduced by abiotic or biotic vectors and, consequently, appraise the amplitude of human impact in such a pristine environment. This research built upon a previous work, which explored microbial diversity in the surface snow surrounding the Concordia Research Station. While that study successfully characterized the bacterial assemblage, detecting fungal diversity was hampered by the low DNA content. To address this knowledge gap, in the present study, we optimized the sampling by increasing ice/snow collected to leverage the final DNA yield. The V4 variable region of the 16S rDNA and Internal Transcribed Spacer (ITS1) rDNA was used to evaluate bacterial and fungal diversity. From the sequencing, we obtained 3,352,661 and 4,433,595 reads clustered in 930 and 3182 amplicon sequence variants (ASVs) for fungi and bacteria, respectively. Amplicon sequencing revealed a predominance of Basidiomycota (49%) and Ascomycota (42%) in the fungal component; Bacteroidota (65.8%) is the main representative among the bacterial phyla. Basidiomycetes are almost exclusively represented by yeast-like fungi. Our findings provide the first comprehensive overview of both fungal and bacterial diversity in the Antarctic Polar Plateau's surface snow/ice near Concordia Station and to identify seasonality as the main driver of microbial diversity; we also detected the most sensitive microorganisms to these factors, which could serve as indicators of human impact in this pristine environment and aid in planetary protection for future exploration missions.
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Affiliation(s)
- Gerardo A. Stoppiello
- Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy; (G.A.S.); (C.R.); (L.S.)
| | - Claudia Coleine
- Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy; (G.A.S.); (C.R.); (L.S.)
| | - Ralf Moeller
- Aerospace Microbiology Research Group, Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center (DLR e.V.), D-51103 Cologne, Germany;
- Department of Natural Sciences, University of Applied Sciences Bonn-Rhein-Sieg, D-53359 Rheinbach, Germany
| | - Caterina Ripa
- Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy; (G.A.S.); (C.R.); (L.S.)
| | - Daniela Billi
- Department of Biology, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Laura Selbmann
- Department of Ecological and Biological Sciences, University of Tuscia, 01100 Viterbo, Italy; (G.A.S.); (C.R.); (L.S.)
- Mycological Section, Italian Antarctic National Museum (MNA), 16128 Genova, Italy
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