6:15 PM - 7:30 PM
[BAO01-P02] Survivality of deinococci under space conditions ? Toward the space exposure experiment in "TANPOPO" mission at ISS
Keywords:International Space Station, Panspermia, Microbe space exposure experiment, "Tanpopo" mission
To address the question whether interplanetary migration of terrestrial microbes are possible, we have proposed and prepared the space capture and space exposure experiments of terrestrial microbes as two of six sub-themes of "TANPOPO mission" on the Exposure Faculty of Japanese Experiment Module "KIBO" of International Space Station (ISS) (Yamagishi et al., 2008). In this mission, we are going to expose microbes in space for one to three (or more) years. There are harsh environmental factors (vacuum, high UV irradiation, ionization radiation, and so on) in space. We have selected the species that show high tolerance to the space conditions.
We are going to use UV- and radiation-resistant deinococcal species: four stains of Deinococcus radiodurans (R1, KH311, rec30, and UVS78), Deinococcus aerius TR0125, and Deinococcus aetherius ST0316. D. aerius and D. aetherius were isolated from upper troposphere and lower stratosphere, respectively (Yang et al. 2009, 2010). They showed high tolerance to UV and radiation, similar to or higher than D. radiodurans R1. In addition, since the DNA repair systems are known to be the keys of high tolerance to UV and radiation in deinococcal species, space survivability of D. radiodurans R1 (wild type strain) will be compared with those of the DNA repair deficient mutant strains of D. radiodurans, KH311 (deficient mutant strain of pprA gene for non-homologous end-joining (NHEJ) repair), rec30 (deficient mutant strain of recA gene for homologous recombination), and UVS78 (deficient mutant strain of uvdE and uvrA1 genes for nucleotide excision repair).
In this paper, we sumarize survivability of deinococcal species for UV-irradiation, heavy ion-irradiation, high vacuum, and periodical change of temperature. Then, we evaluate survivability of deinococcal species in space after one year.
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