MicroColumbus - Effects of the Space Environment and Microgravity on Cells of Halophilic Archaebacteria

Following the successful installation of the Columbus laboratory on the International Space Station (ISS) in February 2008, the ESA facility EXPOSE-E was used to compare the adaptation and survival strategies of microorganisms from different terrestrial habitats. Several extremophilic microorganisms were tested, including the halophilic archaeon Halococcus dombrowskii, which was isolated from a 250-million-year-old Alpine salt deposit in Austria. Samples were returned after 18 months of exposure tothe space environment.

Short Description

The experiments were coordinated by the ADAPT project team. The preparation of samples for the part of the experiment involving Hcc. dombrowskii was carried out at the University of Salzburg. The effects of space conditions on the cells were analysed for viability by staining with fluorescent dyes and by determination of surviving cells by means of growth experiments.

Most of the returned Halococcus cells stained green, which indicated viability, whereas red cells were considered non-viable (Fig. right, top). A novel immuno assay for the detection of thymine dimers, which form under intense UV irradiation, was developed and used for the estimation of DNA damage.

Haloarchaeal cells, which were embedded in artificial halite for the exposure experiments, accumulated preferentially within fluid inclusions, as was shown with fluorescent cells (Fig. right, bottom). Thus, the cells experience a liquid environment on the ISS. Therefore, the possibility of unknown effects due to microgravity on the cells was explored in this project.

A rotary cell culture system from Synthecon (Houston, TX, USA), which is capable of simulating microgravity on a laboratory scale, was used. Preliminary results indicated an increase in resistance to antibiotics as well as alterations in the overall protein composition of those cultures which had been grown in reduced gravity.

Similar responses have been reported to occur in Salmonella bacteria, which are pathogens. This stresses the importance of investigating the effects of reduced gravity on microorganisms and any possible impacts on space station crews. While halophilic archaea are non-pathogenic, they are good model systems for testing responses to microgravity.

Project Partners

Coordinator

University of Salzburg - Division of Molecular Biology, Department of Microbiology - Prof. Helga Stan-Lotter

Partners

German Aerospace Center (DLR) - Petra Rettberg, Principal Investigator for the ADAPT project, Elke Rabbow, team member, Cologne, Germany

Contact Address

University of Salzburg
Division of Molecular Biology
Department of Microbiology
Prof. Helga Stan-Lotter
Billrothstraße 11
A-5020 Salzburg
Tel.: +43 (662) 8044 7233
E-mail: helga.stan-lotter@sbg.ac.at
Web: www.uni-salzburg.at