Identification of lipid-based biomarkers in the high-resolution pyrolysis/mass spectrum of Brucella neotomae

Abstract

High-resolution (HR) mass spectral measurements were performed on pyrolysis products from Brucella neotomae at masses corresponding to low-resolution mass spectral peaks known to be of statistical and biological importance for the identification of diverse bacteria. The high-resolution capabilities allowed the separation of the nominal mass peaks into mass spectral clusters. Empirical formulas were calculated for each peak. Selected standards representing the composition of the bacterial membrane and total bacterial lipid extract were analyzed under identical conditions. High-resolution mass spectral peaks that were found in the whole bacterial cell spectra, in the standards, and total lipid extract were assigned as having originated from lipid-based molecules. Using precursor- and product-ion scans, the electron ionization fragmentation pathways were proposed for most of the peaks. The results from the HR identification of the selected peaks provide biochemical factors leading to the use of the peaks for differentiating bacterial samples.