Analytical and Bioanalytical Chemistry

, Volume 392, Issue 3, pp 439–449

MALDI-TOF mass signatures for differentiation of yeast species, strain grouping and monitoring of morphogenesis markers

  • Jiang Qian
  • Jim E. Cutler
  • Richard B. Cole
  • Yang Cai
Original Paper

DOI: 10.1007/s00216-008-2288-1

Cite this article as:
Qian, J., Cutler, J.E., Cole, R.B. et al. Anal Bioanal Chem (2008) 392: 439. doi:10.1007/s00216-008-2288-1

Abstract

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is demonstrated to be a potentially useful tool for the rapid identification of yeasts, the grouping of Candida albicans strains, and the monitoring of germ tube-specific markers. Co-crystallized with sinapinic acid as the MALDI matrix, intact yeast cells yielded a sufficient number of medium-sized ions (4–15 kDa) in MALDI mass spectra to provide “mass signatures” that were diagnostic of strain type. For most isolates, the mass signatures were affected by the growth medium, length of incubation and the cell preparation method. While the overall past success of this methodology for fungal cells has been relatively low compared to its application to bacteria, fixing the yeast cells in 50% methanol inactivated the cells, reduced cell aggregation in aqueous suspension solution, and more importantly, it significantly improved the mass signature quality. This simple but critical advance in sample treatment improved mass spectrometric signal-to-noise ratios and allowed the identification of yeasts by a mass signature approach. Under optimized conditions, Candida species (C. albicans, C. glabrata, C. krusei, C. kefyr), Aspergillus species (A. terreus, A. fumigatus, A. syndowii) and other yeast genera (Cryptococcus neoformans, Saccharomyces cerevisiae and a Rhodotorula sp.) could be distinguished. Within the C. albicans species, several common ions in the m/z 5,000–10,000 range were apparent in the mass spectra of all tested strains. In addition to shared ions, the mass spectra of individual C. albicans strains permitted grouping of the strains. Principal component analysis (PCA) was employed to confirm spectral reproducibility and C. albicans strain grouping by mass signatures. Finally, C. albicans germ tubes produced MALDI-TOF mass signatures that differed from yeast forms of this species. This is a rapid, sensitive and simple method for identifying yeasts, grouping strains and following the morphogenesis of C. albicans.

https://static-content.springer.com/image/art%3A10.1007%2Fs00216-008-2288-1/MediaObjects/216_2008_2288_Figa_HTML.gif
Figure

 

Keywords

Mass signatureMALDI-TOF mass spectrometryAlcohol fixationYeast differentiationPrincipal component analysis

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Jiang Qian
    • 1
    • 3
  • Jim E. Cutler
    • 1
    • 2
  • Richard B. Cole
    • 3
  • Yang Cai
    • 1
    • 3
  1. 1.Children’s Hospital, New Orleans—The Research Institute for ChildrenNew OrleansUSA
  2. 2.Department of Pediatrics and Microbiology, Immunology and ParasitologyLSU Health Science Center, New OrleansNew OrleansUSA
  3. 3.Department of ChemistryUniversity of New OrleansNew OrleansUSA