The drastic, cold and radiation-filled conditions of outer space present an environmental challenge for any form of life. Crossing the border of centuries, space technology has provided tools for transporting terrestrial life to space environment for studying in situ responses to stress conditions of space. While numerous studies have proved significantly the possibility of microbial transfer through the space, we have been still missing an explicit knowledge of molecular mechanisms allowing survival and adaptation in outer space environment.
In this context, our proposed study aims at utilizing an integrative approach to functionally decipher space-induced mechanisms of microbial survivability. We intend to investigate the molecular mechanisms of microbial survivability and DNA/protein damage following exposure of the radioresistant bacterium Deinococcus radiodurans to harsh space environment at low Earth orbit.
The dehydrated deinococcal cells have already successfully reached the Exposed Facility of the Japanese Experiment Module at the International Space Station (˜400 km) on May 26th, 2015, where they will be exposed for 1, 2, and 3 years in frames of the Tanpopo (Dandelion) mission (JAXA assisted). The dehydrated cells of D. radiodurans will be long-termly influenced by microgravity, temperature changes, high vacuum, cosmic rays, and wide-range UV light.
Furthermore, we will apply the experiences and benefits of the ground-based space simulation facilities at DLR, German Aerospace Center, to expose D. radiodurans to simulated space conditions. Here, we have the advantage to test the space factors separately, in combination and with shorter time frames, exposing dehydrated as well as in suspension cultures of Deinococci cells.
This way we test variable experimental scenarios with respect to exposure time, adaptation processes, etc. In parallel with genetic techniques, we will employ a system approach of a comparative molecular profiling of extra- and intracellular proteins and metabolites to capture a broad range of cellular alterations of Deinococci cells recovering after long-term space exposure and exposure to simulated space conditions.
In preliminary experimental work, we have already established the ground control profiles of D. radiodurans proteins, mRNA transcripts and metabolites. The molecular content of D. radiodurans extracellular milieu (secreted metabolites and proteins) is a special focus of our on-going experiments to elucidate the extracellular alterations caused to Deinococci cells after the space exposure at low Earth orbit.
By means of this, our project offers an integrative program for identifying the components of molecular machinery responsible for a survival of D. radiodurans in conditions of multiple stress factors of low Earth orbit. The identification of molecular mechanisms of Deinococci survivability in outer space environment is essential to understand survival and adaptation strategies of extremophiles to harsh space conditions. Molecular characterization of D. radiodurans survivability at low Earth orbit will promote our understanding of supporting and protecting the life in outer space environment.
University of Vienna
University of Vienna
Dr. Tetyana Milojevic
Althanstraße 14, UZA II
Ebene 5, Lift A