ABSTRACT
Radiation interacts with matter, primarily through the ionization and excitation of electrons in atoms and molecules. Radiobiologists have long believed that ionizing radiation, such as gamma rays, kills cells by shattering DNA. In cells, oxidatively damaged DNA repair enzymes generated by sublethal ionizing radiation doses would be expected to passively promote mutations by misrepair. Mechanical culture conditions in the quiescent microgravity environment of space flight are characterized by significant reductions in fluid shear. The use of magnetic levitation has also been introduced to balance the force of gravity on a levitating object. Very few attempts were made to mimic space-ionizing radiation on ground and compare it to actual space flight experiment involving microorganisms. We could put forward the importance of medium composition and culture setup on the response of the bacterium to space flight-related environmental conditions but low overlap was obtained for both the microgravity simulation and the ionizing radiation experiments compared to the space flight experiments.
