TY - JOUR
T1 - Melanin is effective in protecting fast and slow growing fungi from various types of ionizing radiation
AU - Pacelli, Claudia
AU - Bryan, Ruth A.
AU - Onofri, Silvano
AU - Selbmann, Laura
AU - Shuryak, Igor
AU - Dadachova, Ekaterina
N1 - Funding Information:
E.D., R.B. and I.S. thank the Defense Threat Reduction Agency (DTRA) grant HDTRA1-15-1-0058 for supporting research. C.P., S.O. and L.S. acknowledge the ASI (Italian Space Agency) for funding BIOMEX-MCF, PNRA (Italian National Program for Antarctic Research) for supporting sample collection in Antarctica and the Italian National Antarctic Museum ‘Felice Ippolito’, for funding CCFEE (Culture Collection of Fungi From Extreme Environments).
Publisher Copyright:
© 2017 Society for Applied Microbiology and John Wiley & Sons Ltd
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Melanin is a ubiquitous pigment with unique physicochemical properties. The resistance of melanized fungi to cosmic and terrestrial ionizing radiation suggests that melanin also plays a pivotal role in radioprotection. In this study, we compared the effects of densely-ionizing deuterons and sparsely-ionizing X-rays on two microscopic fungi capable of melanogenesis. We utilized the fast-growing pathogenic basiodiomycete forming an induced DOPA-melanin, Cryptococcus neoformans (CN); and the slow-growing environmental rock-inhabiting ascomycete synthesizing a constitutive DHN-melanin, Cryomyces antarcticus (CA); melanized and non-melanized counterparts were compared. CA was more resistant to deuterons than CN, and similar resistance was observed for X-rays. Melanin afforded protection against high-dose (1.5 kGy) deuterons for both CN and CA (p-values < 10−4). For X-rays (0.3 kGy), melanin protected CA (p-values < 10−4) and probably CN. Deuterons increased XTT activity in melanized strains of both species, while the activity in non-melanized cells remained stable or decreased. For ATP levels the reverse occurred: it decreased in melanized strains, but not in non-melanized ones, after deuteron exposure. For both XTT and ATP, which reflect the metabolic activity of the cells, larger and more statistically-significant differences as a function of melanization status occurred in CN. Our data show, for the first time, that melanin protected both fast-growing and slow-growing fungi from high doses of deuterons under physiological conditions. These observations may give clues for creating melanin-based radioprotectors.
AB - Melanin is a ubiquitous pigment with unique physicochemical properties. The resistance of melanized fungi to cosmic and terrestrial ionizing radiation suggests that melanin also plays a pivotal role in radioprotection. In this study, we compared the effects of densely-ionizing deuterons and sparsely-ionizing X-rays on two microscopic fungi capable of melanogenesis. We utilized the fast-growing pathogenic basiodiomycete forming an induced DOPA-melanin, Cryptococcus neoformans (CN); and the slow-growing environmental rock-inhabiting ascomycete synthesizing a constitutive DHN-melanin, Cryomyces antarcticus (CA); melanized and non-melanized counterparts were compared. CA was more resistant to deuterons than CN, and similar resistance was observed for X-rays. Melanin afforded protection against high-dose (1.5 kGy) deuterons for both CN and CA (p-values < 10−4). For X-rays (0.3 kGy), melanin protected CA (p-values < 10−4) and probably CN. Deuterons increased XTT activity in melanized strains of both species, while the activity in non-melanized cells remained stable or decreased. For ATP levels the reverse occurred: it decreased in melanized strains, but not in non-melanized ones, after deuteron exposure. For both XTT and ATP, which reflect the metabolic activity of the cells, larger and more statistically-significant differences as a function of melanization status occurred in CN. Our data show, for the first time, that melanin protected both fast-growing and slow-growing fungi from high doses of deuterons under physiological conditions. These observations may give clues for creating melanin-based radioprotectors.
UR - http://www.scopus.com/inward/record.url?scp=85013427875&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85013427875&partnerID=8YFLogxK
U2 - 10.1111/1462-2920.13681
DO - 10.1111/1462-2920.13681
M3 - Article
AN - SCOPUS:85013427875
SN - 1462-2912
VL - 19
SP - 1612
EP - 1624
JO - Environmental Microbiology
JF - Environmental Microbiology
IS - 4
ER -