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Jaakkola ST, Zerulla K, Guo Q, Liu Y, Ma H, Yang C, Bamford DH, Chen X, Soppa J, Oksanen HM. Halophilic archaea cultivated from surface sterilized middle-late eocene rock salt are polyploid. PLoS One 2014; 9:e110533. [PMID: 25338080 PMCID: PMC4206341 DOI: 10.1371/journal.pone.0110533] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/11/2014] [Indexed: 11/24/2022] Open
Abstract
Live bacteria and archaea have been isolated from several rock salt deposits of up to hundreds of millions of years of age from all around the world. A key factor affecting their longevity is the ability to keep their genomic DNA intact, for which efficient repair mechanisms are needed. Polyploid microbes are known to have an increased resistance towards mutations and DNA damage, and it has been suggested that microbes from deeply buried rock salt would carry several copies of their genomes. Here, cultivable halophilic microbes were isolated from a surface sterilized middle-late Eocene (38–41 million years ago) rock salt sample, drilled from the depth of 800 m at Yunying salt mine, China. Eight unique isolates were obtained, which represented two haloarchaeal genera, Halobacterium and Halolamina. We used real-time PCR to show that our isolates are polyploid, with genome copy numbers of 11–14 genomes per cell in exponential growth phase. The ploidy level was slightly downregulated in stationary growth phase, but the cells still had an average genome copy number of 6–8. The polyploidy of halophilic archaea living in ancient rock salt might be a factor explaining how these organisms are able to overcome the challenge of prolonged survival during their entombment.
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Affiliation(s)
- Salla T. Jaakkola
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Karolin Zerulla
- Institute for Molecular Biology, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Qinggong Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Ying Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Hongling Ma
- Institute of Rock and Soil Mechanics, The Chinese Academy of Sciences, Wuhan, Hubei, People's Republic of China
| | - Chunhe Yang
- Institute of Rock and Soil Mechanics, The Chinese Academy of Sciences, Wuhan, Hubei, People's Republic of China
| | - Dennis H. Bamford
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Xiangdong Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, People's Republic of China
- * E-mail: (HMO); (JS); (XC)
| | - Jörg Soppa
- Institute for Molecular Biology, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
- * E-mail: (HMO); (JS); (XC)
| | - Hanna M. Oksanen
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland
- * E-mail: (HMO); (JS); (XC)
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Parnell J, Mazzini A, Honghan C. Fluid inclusion studies of chemosynthetic carbonates: strategy for seeking life on Mars. ASTROBIOLOGY 2002; 2:43-57. [PMID: 12449854 DOI: 10.1089/153110702753621330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fluid inclusions in minerals hold the potential to provide important data on the chemistry of the ambient fluids during mineral precipitation. Especially interesting to astrobiologists are inclusions in low-temperature minerals that may have been precipitated in the presence of microorganisms. We demonstrate that it is possible to obtain data from inclusions in chemosynthetic carbonates that precipitated by the oxidation of organic carbon around methane-bearing seepages. Chemosynthetic carbonates have been identified as a target rock for astrobiological exploration. Other surficial rock types identified as targets for astrobiological exploration include hydrothermal deposits, speleothems, stromatolites, tufas, and evaporites, each of which can contain fluid inclusions. Fracture systems below impact craters would also contain precipitates of minerals with fluid inclusions. As fluid inclusions are sealed microchambers, they preserve fluids in regions where water is now absent, such as regions of the martian surface. Although most inclusions are < 5 microns, the possibility to obtain data from the fluids, including biosignatures and physical remains of life, underscores the advantages of technological advances in the study of fluid inclusions. The crushing of bulk samples could release inclusion waters for analysis, which could be undertaken in situ on Mars.
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Affiliation(s)
- John Parnell
- Department of Geology and Petroleum Geology, University of Aberdeen King's College, Aberdeen AB24 3UE, U.K.
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McGenity TJ, Gemmell RT, Grant WD, Stan-Lotter H. Origins of halophilic microorganisms in ancient salt deposits. Environ Microbiol 2000; 2:243-50. [PMID: 11200425 DOI: 10.1046/j.1462-2920.2000.00105.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- T J McGenity
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, UK.
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