Detection of specific Bacillus anthracis spore biomarkers by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) was applied for the characterization of Bacillus anthracis spore biomarkers. B. anthracis spores were extracted under a simple procedure, followed by linear mode analysis, using sinapinic acid as the matrix. Several markers with a mass range of 4–7 kDa were detected in three B. anthracis strains: Vollum, Sterne and V770‐NP1‐R. Similar spectra were also obtained for spore extracts of two members of the B. cereus group: B. thuringiensis and B. cereus , but not for B. mycoides, B. subtilis or B. licheniformis , suggesting that these markers are specific to closely related members of the B. cereus group. When α‐cyano‐4‐hydroxycinnamic acid was used as the matrix, at least four additional new markers within a mass range of 2–4 kDa could be detected in all B. anthracis spore extracts. These markers, corresponding to a molecular weight of 2528.3, 2792.4, 3077.4, and 3590.7 Da, have not been observed in extracts of the three closely related Bacillus species – B. cereus, B. thuringiensis and B. mycoides . These unique B. anthracis biomarkers, which were isotopically resolved and reproducibly detected in the highly accurate MALDI‐TOFMS reflectron mode, may be useful as a basis for rapid and specific identification of B. anthracis strains. Copyright © 2001 John Wiley & Sons, Ltd.