Pneumocystis melanins confer enhanced organism viability

Crystal R. Icenhour, Theodore J. Kottom, Andrew Harold Limper

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Pneumocystis continues to represent an important opportunistic fungal pathogen of those with compromised immunity. Thus, it is crucial to identify factors that affect its viability and pathogenicity. We previously reported the first identification of melanins in Pneumocystis. In the present study, we sought to further characterize these components and define the function for these melanins. Melanins extracted from Pneumocystis and melanized Pneumocystis cells were analyzed by electron spin resonance spectroscopy, revealing spectra consistent with melanins from other fungi. Immunofluorescence assays using anti-melanin monoclonal antibodies showed that melanins are widely present across Pneumocystis host species, including mouse-, ferret-, and human-derived Pneumocystis organisms, as well as Pneumocystis carinii derived from rat. Using immunoelectron microscopy, melanins were found to localize to the cell wall and cytoplasm of P. carinii cysts, as well as to intracystic bodies within mature cysts. Next, the role of melanins on the maintenance of Pneumocystis viability was determined by using quantitative reverse transcription-PCR measurement of the heat shock protein mRNA under adverse environmental conditions. Using a new method to promote the melanization of Pneumocystis, we observed that strongly melanized Pneumocystis retained viability to a greater degree when exposed to UV irradiation or desiccation compared to less-pigmented organisms. These studies support our previous identification of Pneumocystis melanins across the genus, further characterize these Pneumocystis components, and demonstrate that melanins protect Pneumocystis from environmental stressors.

Original languageEnglish (US)
Pages (from-to)916-923
Number of pages8
JournalEukaryotic Cell
Volume5
Issue number6
DOIs
StatePublished - Jun 2006

Fingerprint

Pneumocystis
Melanins
melanin
viability
organisms
Pneumocystis carinii
Cysts
Desiccation
melanization
Ferrets
Immunoelectron Microscopy
ferrets
electron paramagnetic resonance spectroscopy
Electron Spin Resonance Spectroscopy
Heat-Shock Proteins
heat shock proteins
Cell Wall
fluorescent antibody technique
Reverse Transcription
Fluorescent Antibody Technique

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Microbiology

Cite this

Pneumocystis melanins confer enhanced organism viability. / Icenhour, Crystal R.; Kottom, Theodore J.; Limper, Andrew Harold.

In: Eukaryotic Cell, Vol. 5, No. 6, 06.2006, p. 916-923.

Research output: Contribution to journalArticle

Icenhour, Crystal R. ; Kottom, Theodore J. ; Limper, Andrew Harold. / Pneumocystis melanins confer enhanced organism viability. In: Eukaryotic Cell. 2006 ; Vol. 5, No. 6. pp. 916-923.
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