TY  - JOUR
A1  - Jaakkola, Salla T.
A1  - Zerulla, Karolin
A1  - Guo, Qinggong
A1  - Liu, Ying
A1  - Ma, Hongling
A1  - Yang, Chunhe
A1  - Bamford, Dennis H.
A1  - Chen, Xiangdong
A1  - Soppa, Jörg
A1  - Oksanen, Hanna M.
T1  - Halophilic archaea cultivated from surface sterilized middle-late Eocene rock salt are polyploid
T2  - PLoS One
N2  - 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.
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/35300
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-353002
SN  - 1932-6203
N1  - Copyright: © 2014 Jaakkola et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
VL  - 9
IS  - (10):e110533
PB  - PLoS
CY  - Lawrence, Kan.
ER  -