Biomarkers of Aspergillus spores: Strain typing and protein identification

We applied both matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometric and 1D sodium dodecylsulfate polyacrylamide gel electrophoretic (1D-PAGE) approaches for direct analysis of intact fungal spores of twenty four Aspergillus species. In parallel, we optimized various protocols for protein extraction from Aspergillus spores using acidic conditions, step organic gradient and variable sonication treatment. The MALDI-TOF mass spectra obtained from optimally prepared samples provided a reproducible fingerprint demonstrating the capability of the MALDI-TOF approach to type and characterize different fungal strains within the Aspergillus genus. Mass spectra of intact fungal spores provided signals mostly below 20 kDa. The minimum material amount represented 0.3 μg (10,000 spores). Proteins with higher molecular weight were detected by 1D-PAGE. Eleven proteins were identified from three selected strains in the range 5–25 kDa by the proteomic approach. Hemolysin and hydrophobin have the highest relevance in host–pathogen interactions.