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The effect of protracted X‐ray exposure on cell survival and metabolic activity of fast and slow growing fungi capable of melanogenesis
Author(s) -
Pacelli Claudia,
Bryan Ruth A.,
Onofri Silvano,
Selbmann Laura,
Zucconi Laura,
Shuryak Igor,
Dadachova Ekaterina
Publication year - 2018
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12632
Subject(s) - microfungi , biology , cryptococcus , cryptococcus neoformans , intracellular , hypha , cell survival , metabolic activity , microbiology and biotechnology , biochemistry , in vitro , physiology , botany
Summary The aim of this study was to analyse how protracted exposure to X‐rays delivered at low dose rates of 0.0032–0.052 kGy h −1 affects the survival and metabolic activity of two microfungi capable of melanogenesis: fast‐growing Cryptococcus neoformans (CN) and slow‐growing Cryomyces antarcticus (CA). Melanized CN and CA cells survived the protracted exposure better than non‐melanized ones, which was consistent with previous reports on the radioprotective role of melanin in these fungi after high dose rate exposures. The survival data were described by the linear quadratic dose response model. The XTT metabolic profiles were practically identical for melanized CN and CA with activity dose‐dependent increasing: no changes in the activity of the non‐melanized CN and CA were recorded by this assay. In contrast, the MTT assay, which measures the intracellular energy‐related processes, recorded an increase in activity of non‐melanized CN and CA cells, but not in their melanized counterparts. This could reflect intensive repair processes initiated by the non‐melanized cells post exposure. This study suggests that differences in radiation responses between melanized and non‐melanized fungal cells occur over a wide range of radiation dose rates.