The SOS-LUX-TOXICITY-Test on the International Space Station.

For the safety of astronauts and to ensure the stability and integrity of the genome of microorganisms and plants used in bioregenerative life support systems, it is important to improve our knowledge of the combined action of (space) radiation and microgravity. The SOS-LUX-TOXICITY test, as part of the TRIPLE-LUX project (accepted for flight at Biolab in Columbus on the International Space Station, (ISS)), will provide an estimation of the health risk resulting from exposure of astronauts to the radiation environment of space in microgravity. The project will: (i) increase our knowledge of biological/health threatening action of space radiation and enzymatic DNA repair; (ii) uncover cellular mechanisms of synergistic interaction of microgravity and space radiation; (iii) provide specified biosensors for spacecraft milieu examination; and (iv) provide experimental data on stability and integrity of bacterial DNA in spacecrafts. In the bacterial biosensor "SOS-LUX-Test" developed at DLR (patent), bacteria are transformed with the pBR322-derived plasmid pPLS-1 or the similar, advanced plasmid SWITCH, both carrying the promoterless lux operon of Photobacterium leiognathi as the reporter element controlled by a DNA damage-dependent SOS promoter as sensor element. A short description of the space experiment is given, and the current status of adaptation of the SOS-LUX-Test to the ISS, i.e. first results of sterilization, biocompatibility and functional tests performed with the already available hardware and bread board model of the automated space hardware under development, is described here.