Melanized fungus grows well in the Chernobyl reactor and in high radiation of space stations. The fungus can prosper when radiation is 500 times background levels. The Melanin absorbs all types of electromagnetic radiation and could be used for energy transduction and radiation shielding.
Melanized fungal species in the Chernobyl reactor have enhanced growth when exposed to ionizing radiation. Fungi colonize space stations and adapt morphologically to extreme conditions. Radiation exposure causes upregulation of many key genes, and an inducible microhomology-mediated recombination pathway could be a potential mechanism of adaptive evolution in eukaryotes. The discovery of melanized organisms in high radiation environments, the space stations, Antarctic mountains, and in the reactor cooling water combined with phenomenon of ‘radiotropism’ raises the tantalizing possibility that melanins have functions analogous to other energy harvesting pigments such as chlorophylls.
Melanized W. dermatitidis and C. neoformans cells exposed to ionizing radiation approximately 500 times higher than background grew significantly faster as indicated by higher CFUs, more dry weight biomass and 3-fold greater incorporation of 14C-acetate than non-irradiated melanized cells or irradiated albino mutants. In addition, radiation enhanced the growth of melanized C. sphaerospermum cells under limited nutrients conditions. The observations that melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation raised the intriguing possibility that melanin can function in energy capture and utilization.
Melanin pigments are found in all biological kingdoms, suggesting that these compounds are ancient molecules that emerged early in the course of evolution. Melanins are complex polymers with a variety of properties that can be made enzymatically from relatively simple precursors. A remarkable aspect of melanins is their ability to absorb all types of electromagnetic radiation which endows them with the capacity for both energy transduction and shielding. The findings of melanized organisms in high radiation environments such as the damaged reactor at Chernobyl, the space station, Antarctic mountains, and reactor cooling water combined with phenomenon of ‘radiotropism’ raises the tantalizing possibility that melanins have functions analogous to other energy harvesting pigments such as chlorophylls.