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 Bacillu s anthracis spore biomarkers. B. anthracis spores were extracted under a si mple procedure, followed by linear mode analysis, using sinapinic acid as t he matrix. Several markers with a mass range of 4-7 kDa were detected in th ree B. anthracis strains: Vollum, Sterne and V770-NP1-R. Similar spectra we re 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 relate d members of the B. cereus group. When alpha -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. Thes e markers, corresponding to a molecular weight of 2528.3, 2792.4, 3077.4, a nd 3590.7 Da, have not been observed in extracts of the three closely relat ed Bacillus species - B. cereus, B. thuringiensis and B. mycoides. These un ique B. anthracis biomarkers, which were isotopically resolved and reproduc ibly detected in the highly accurate MALDI-TOFMS reflectron mode, may be us eful as a basis for rapid and specific identification of B. anthracis strai ns. Copyright (C) 2001 John Wiley & Sons, Ltd.