Haloarchaeal diversity in 23, 121 and 419 MYA salts

Park, Jong Soo; Vreeland, Russell H.; Cho, B. C.; Lowenstein, Tim K.; Timofeeff, Michael N.; Rosenzweig, William D.

doi:10.1111/j.1472-4669.2009.00218.x

Cited by 50 publications

(43 citation statements)

References 38 publications

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“…There are several highly cited and critically debated reports of bacterial DNA or cells that have apparently survived for many millions of years enclosed in rock salt (e.g., Vreeland et al 2000, Hebsgaard et al 2005, Park et al 2009 or in amber (Cano & Borucki 1995). In the latter observations, it is striking that the isolated organisms were endospore formers.…”

Section: Age and Agingmentioning

confidence: 94%

Slow Microbial Life in the Seabed

Jørgensen

Marshall

2016

Annu. Rev. Mar. Sci.

141

152

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Global microbial cell numbers in the seabed exceed those in the overlying water column, yet these organisms receive less than 1% of the energy fixed as organic matter in the ocean. The microorganisms of this marine deep biosphere subsist as stable and diverse communities with extremely low energy availability. Growth is exceedingly slow, possibly regulated by virus-induced mortality, and the mean generation times are tens to thousands of years. Intermediate substrates such as acetate are maintained at low micromolar concentrations, yet their turnover time may be several hundred years. Owing to slow growth, a cell community may go through only 10,000 generations from the time it is buried beneath the mixed surface layer until it reaches a depth of tens of meters several million years later. We discuss the efficiency of the energy-conserving machinery of subsurface microorganisms and how they may minimize energy consumption through necessary maintenance, repair, and growth.

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Section: Age and Agingmentioning

confidence: 94%

Slow Microbial Life in the Seabed

Jørgensen

Marshall

2016

Annu. Rev. Mar. Sci.

141

152

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“…[15][16][17][18][19]). Sophisticated sterilization protocols have been developed to exclude that the isolated strains might have been contaminations with present-day haloarchaea.…”

Section: Survival Over Geological Timesmentioning

confidence: 97%

Evolutionary advantages of polyploidy in halophilic archaea

Soppa

2013

Biochemical Society Transactions

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Several species of haloarchaea have been shown to be polyploid and thus this trait might be typical for and widespread in haloarchaea. In the present paper, nine different possible evolutionary advantages of polyploidy for haloarchaea are discussed, including low mutation rate, radiation/desiccation resistance, gene redundancy and survival over geological times and at extraterrestrial sites. Experimental indications exist for all but one of these evolutionary advantages. Several of the advantages require gene conversion, which has been shown to be present and active in haloarchaea.

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“…We previously showed that the high halide concentration in the cytoplasm of H. salinarum was a major factor in protecting its macromolecules against the oxidative effects of IR (34) and resulted directly from its adaptation to a high-salt environment. H. salinarum is found in hypersaline pools, where it is subjected to cycles of desiccation and rehydration (15), and halophiles have been shown to survive extended periods of time encased inside salt crystals (42). The adaptation of H. salinarum to desiccation is another example of the link between IR resistance and desiccation that has been reported for D. radiodurans and other dry-climate-adapted bacteria (20,38,45) and for some lower eukaryotes, such as rotifers and tardigrades (22,26).…”

Section: Discussionmentioning

confidence: 99%

A Major Role for Nonenzymatic Antioxidant Processes in the Radioresistance of Halobacterium salinarum

et al. 2011

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Oxidative stress occurs when the generation of reactive oxygen species (ROS) exceeds the capacity of the cell's endogenous systems to neutralize them. Our analyses of the cellular damage and oxidative stress responses of the archaeon Halobacterium salinarum exposed to ionizing radiation (IR) revealed a critical role played by nonenzymatic antioxidant processes in the resistance of H. salinarum to IR. ROS-scavenging enzymes were essential for resistance to chemical oxidants, yet those enzymes were not necessary for H. salinarum's resistance to IR. We found that protein-free cell extracts from H. salinarum provided a high level of protection for protein activity against IR in vitro but did not protect DNA significantly. Compared with cell extracts of radiation-sensitive bacteria, H. salinarum extracts were enriched in manganese, amino acids, and peptides, supporting an essential role in ROS scavenging for those small molecules in vivo. With regard to chemical oxidants, we showed that the damage caused by gamma irradiation was mechanistically different than that produced by hydrogen peroxide or by the superoxide-generating redox-cycling drug paraquat. The data presented support the idea that IR resistance is most likely achieved by a "metabolic route," with a combination of tightly coordinated physiological processes.

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Haloarchaeal diversity in 23, 121 and 419 MYA salts

Cited by 50 publications

References 38 publications

Slow Microbial Life in the Seabed

Slow Microbial Life in the Seabed

Evolutionary advantages of polyploidy in halophilic archaea

A Major Role for Nonenzymatic Antioxidant Processes in the Radioresistance of Halobacterium salinarum

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