Evaluation of the Resistance of Chroococcidiopsis spp. to Sparsely and Densely Ionizing Irradiation
Studying the resistance of cyanobacteria to ionizing radiation provides relevant information regarding astrobiology-related topics including the search for life on Mars, lithopanspermia, and biological life-support systems. Here, we report on the resistance of desert cyanobacteria of the genus Chroococcidiopsis, which were exposed (as part of the STARLIFE series of experiments) in both hydrated and dried states to ionizing radiation with different linear energy transfer values (0.2 to 200 keV/mm). Irradiation with up to 1 kGy of He or Si ions, 2 kGy of Fe ions, 5 kGy of X-rays, or 11.59 kGy of gamma rays (Co-60) did not eradicate Chroococcidiopsis populations, nor did it induce detectable damage to DNA or plasma membranes. The relevance of these results for astrobiology is briefly discussed.