This chapter will address the applications of protein-based bioinformatics to analysis of microorganisms introduced intact into the instrumental system for rapid processing and analysis. Strategies that require offline extraction and fractionation of proteins will not be discussed. Although the amplification of nucleic acids is a powerful approach, especially coupled with mass spectrometry, 1-5 it requires extraction and processing, and thus is not included.
Intact bacteria were first introduced into a mass spectrometer for analysis of molecular biomarkers without processing and fractionation around 1975. The ionization techniques available at the time limited analysis to secondary metabolites that could be volatilized, such as quinines and diglycerides, and vigorous pyrolysis of bacteria was explored as an alternative. 7 Although biomarkers were destroyed in pyrolysis strategies, computer-supported cluster analysis was developed to characterize pure samples.
The introduction of fast-atom bombardment (FAB) half a decade later extended the analyst's biomarker repertoire to intact polar lipids, desorbed