Q-307. Response of the Proteobacteria Cupriavidus metallidurans CH34 and Rhodospirillum rubrum S1H to Space Flight Conditions

N. Leys1, F. Mastroleo1, R. Wattiez2, L. Hendrickx1, S. Baatout1, M. A. Benotmane1, M. F. Mergeay1;
1SCK/CEN Belgian Nuclear Energy Ctr., Mol, BELGIUM, 2Univ. Mons-Hainaut, Mons, BELGIUM.

Background. When man goes to space, inevitably microbes hitchhike along, some needed, others unwanted. The equilibrium between beneficial and harmful microbial activity is fragile but extremely important, especially in space. Aim. The aim of this work was to investigate the physiological and metabolic response and adaptation of the bacteria Cupriavidus metallidurans CH34 and the Rhodospirillum rubrum S1H to space flight conditions. R. rubrum is a key organism in the 'MELiSSA' regenerative life support system for space. The strains were grown (1) in the International Space Station (ISS) (MESSAGE and BASE flight experiments), (2) in the Rotating Wall Vessel (RWV) and on the Random Positioning Machine (RPM) mimicking microgravity, and (3) in simulated space flight radiation conditions on ground. Results. Space flight experiments demand unusual culture conditions and it was clear that, pre-, in- and post-flight incubation conditions are critical and should be controlled, monitored and taken into account as much as possible when comparing space flight with ground grown cells. Via flowcytometry, minor but distinct changes in physiology and metabolism were observed in the cells grown in space flight when compared to ground control cultures. After a 10-day space mission, transcriptome analysis using total genome DNA-microarray chips showed up-regulation of several genes, some typically involved in oxidative stress response. Proteome analysis using 2D-gel electrophoresis and HPLC-MS/MS identified in addition, several proteins over-produced in space conditions. The ground simulation experiments indicated that space microgravity and radiation (even at low doses inside the spacecraft) could induce separately and/or combined certain physiology properties and metabolic pathways observed in space experiments. Conclusions. Space flight can alter the physiology and the metabolism of bacteria. The observed changes could be of importance for the technological development of microbial monitoring and life support systems.