| Affiliation: | 1. Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia;2. Department of Genetics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia;3. Department of Microbiology, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia;4. Department of nuclear reactions, Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State, Moscow, Russia;5. Bach Institute of Biochemistry, Federal Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia;6. Department of Mycology and Algology, Faculty of Biology, Lomonosov Moscow State University, Moscow 119234, Russia;7. Institute of Biomedical Problems, Moscow 123007, Russia;8. Department of Physics, Moscow State University, Moscow 119991, Russia;9. Bioengineering Department, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia;10. Technical University of Berlin, Institute of Chemistry, Berlin, Germany;11. Department of Biochemistry, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia |
| Abstract: | Cyanobacteria are thought to be responsible for pioneering dioxygen production and the so-called “Great Oxygenation Event” that determined the formation of the ozone layer and the ionosphere restricting ionizing radiation levels reaching our planet, which increased biological diversity but also abolished the necessity of radioprotection. We speculated that ancient protection mechanisms could still be present in cyanobacteria and studied the effect of ionizing radiation and space flight during the Foton-M4 mission on Synechocystis sp. PCC6803. Spectral and functional characteristics of photosynthetic membranes revealed numerous similarities of the effects of α-particles and space flight, which both interrupted excitation energy transfer from phycobilisomes to the photosystems and significantly reduced the concentration of phycobiliproteins. Although photosynthetic activity was severely suppressed, the effect was reversible, and the cells could rapidly recover from the stress. We suggest that the actual existence and the uncoupling of phycobilisomes may play a specific role not only in photo-, but also in radioprotection, which could be crucial for the early evolution of Life on Earth. |
