Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi

Ekaterina Dadachova, Ruth A. Bryan, Xianchun Huang, Tiffany Moadel, Andrew D. Schweitzer, Philip Aisen, Joshua D. Nosanchuk, Arturo Casadevall

Research output: Contribution to journalArticle

182 Citations (Scopus)

Abstract

Background: Melanin pigments are ubiquitous in nature. Melanized microorganisms are often the dominating species in certain extreme environments, such as soils contaminated with radionuclides, suggesting that the presence of melaninis beneficial in their life cycle. We hypothesized that ionizing radiation could change the electronic properties of melanin and might enhance the growth of melanized microorganisms. Methodology/Principal Findings: Ionizing irradiation changed the electron spin resonance (ESR) signal of melanin, consistent with changes in electronic structure. Irradiated melanin manifested a 4-fold increase in its capacity to reduce NADH relative to non-irradiated melanin. HPLC analysis of melanin from fungi grown on different substrates revealed chemical complexity, dependence of melanin composition on the growth substrate and possible influence of melanin composition on its interaction with ionizing radiation. XTT/MTT assays showed increased metabolic activity of melanized C. neoformans cells relative to non-melanized cells, and exposure to ionizing radiation enhanced the electron-transfer properties of melanin in melanized cells. Melanized Wangiella dermatitidisand Cryptococcus neoformanscells 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 Cladosporium sphaerospermum cells under limited nutrients conditions. Conclusions/Significance: Exposure of melanin to ionizing radiation, and possibly other forms of electromagnetic radiation, changes its electronic properties. Melanized fungal cells manifested increased growth relative to non-melanized cells after exposure to ionizing radiation, raising intriguing questions about a potential role for melanin in energy capture and utilization.

Original languageEnglish (US)
Article numbere457
JournalPLoS One
Volume2
Issue number5
DOIs
StatePublished - May 23 2007

Fingerprint

Melanins
Ionizing radiation
melanin
Ionizing Radiation
ionizing radiation
Fungi
Electronic properties
electronics
fungi
Growth
cells
Microorganisms
Cladosporium sphaerospermum
Exophiala
electromagnetic radiation
Electromagnetic Radiation
Cladosporium
microorganisms
Cryptococcus
electron paramagnetic resonance spectroscopy

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Dadachova, E., Bryan, R. A., Huang, X., Moadel, T., Schweitzer, A. D., Aisen, P., ... Casadevall, A. (2007). Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi. PLoS One, 2(5), [e457]. https://doi.org/10.1371/journal.pone.0000457

Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi. / Dadachova, Ekaterina; Bryan, Ruth A.; Huang, Xianchun; Moadel, Tiffany; Schweitzer, Andrew D.; Aisen, Philip; Nosanchuk, Joshua D.; Casadevall, Arturo.

In: PLoS One, Vol. 2, No. 5, e457, 23.05.2007.

Research output: Contribution to journalArticle

Dadachova, E, Bryan, RA, Huang, X, Moadel, T, Schweitzer, AD, Aisen, P, Nosanchuk, JD & Casadevall, A 2007, 'Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi', PLoS One, vol. 2, no. 5, e457. https://doi.org/10.1371/journal.pone.0000457
Dadachova, Ekaterina ; Bryan, Ruth A. ; Huang, Xianchun ; Moadel, Tiffany ; Schweitzer, Andrew D. ; Aisen, Philip ; Nosanchuk, Joshua D. ; Casadevall, Arturo. / Ionizing radiation changes the electronic properties of melanin and enhances the growth of melanized fungi. In: PLoS One. 2007 ; Vol. 2, No. 5.
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