HALOSPACE - Response of Halococcus dombrowskii Cells to the Space Environment and Preparation for Exposure Experiments on the International Space Station
The European Technology Exposure Facility (EuTEF) on the outside of the Columbus laboratory of the International Space Station (ISS) contains the subsection EXPOSE-E, which is currently used for five biological experiments. One of them is ADAPT, which is coordinated by Principal Investigator Dr. Petra Rettberg, DLR (German Aerospace Center), Köln, and contains an Austrian contribution called HALOSPACE.
The ADAPT experiment will compare the survival strategies and adaptation of three highly resistant microorganisms from different terrestrial habitats: a photosynthetic cyanobacterium, which is exposed to high levels of solar UV radiation in its natural environment, an extremely halophilic archaebacterium, Halococcus dombrowskii, which was isolated from a 250 million year old alpine salt deposit near Bad Ischl, and Bacillus subtilis, a spore-forming soil bacterium.
The preparation of samples and the analytical work involving Hc. dombrowskii are being carried out at the University of Salzburg. Cells of Hc. dombrowskii were deposited on quartz discs of 11 mm diameter and were accommodated into the sample holder. Due to their content of carotenoids, cells of Hc. dombrowskii are naturally of intense reddish pigmentation, which is thought to afford protection from strong UV radiation.
To test this hypothesis, non-pigmented variants of Hc. dombrowskii cells, obtained by growth in different culture media, were also used in order to assess any differences in the extent of protection against cellular damage.
Following the successful transport of the Columbus laboratory to the ISS on February 8, 2008, the experiments were started on February 20, 2008, by opening the lids of EXPOSE-E. The planned duration of exposure to the space environment are being 18 months.
The expected results should give insights about microbial survival under space conditions for extended times and the potential genetic adaptation to those conditions by survivors. They should thus allow an improved judgement on the possibility of interplanetary transfer of microbial life forms, as well as provide insights with regard to issues of avoidance of forward and backward contamination (planetary protection).
University of Salzburg, Division of Molecular Biology, Department of Microbiology - Prof. Dr. Helga Stan-Lotter
DLR, German Aerospace Center - Dr. Petra Rettberg (Principal Investigator)