Microwave supported hydrolysis prepares Bacillus spores for proteomic analysis

Rapid identification of Bacillus spores in the environment has depended primarily on a family of small acid soluble proteins (SASPs) as biomarkers. However, SASP sequences and molecular masses are similar or identical in some critical cases. For example, some strains of B. subtilis, and B. thuringiensis cannot be distinguished from strains of B. anthracis based on SASPs. Consequently, additional or alternative biomarkers should be sought. In this study microwave-assisted hot acid hydrolysis was coupled with mass spectrometry as a potentially powerful approach to the rapid automatable characterization of Bacillus spores. Hot acid provides lysis of the spores, Asp-selective hydrolysis of proteins, and peptides compatible with automated analysis of either peptide fingerprints or tandem mass spectra. Peptide biomarkers are compared here for a selection of Bacillus spores, and peptides unique to each spore type are identified.