Detection of Fatty Acids from Intact Microorganisms by Molecular Beam Static Secondary Ion Mass Spectrometry

Journal Article · Sun Jun 01 00:00:00 EDT 2003 · Journal of Microbiological Methods

DOI:https://doi.org/10.1016/S0167-7012(02)00236-1· OSTI ID:912033

Ingram, Jani Cheri; Lehman, Richard Michael; Bauer, William Francis; O'Connell, Sean Patrick; Colwell, Frederick Scott; Shaw, Andrew D

We report the use of a surface analysis approach, static secondary ion mass spectrometry (SIMS) equipped with a molecular (ReO4-) ion primary beam, to analyze the surface of intact microbial cells. SIMS spectra of 28 microorganisms were compared to fatty acid profiles determined by gas chromatographic analysis of transesterfied fatty acids extracted from the same organisms. The results indicate that surface bombardment using the molecular primary beam cleaved the ester linkage characteristic of bacteria at the glycerophosphate backbone of the phospholipid components of the cell membrane. This cleavage enables direct detection of the fatty acid conjugate base of intact microorganisms by static SIMS. The limit of detection for this approach is approximately 107 bacterial cells/cm2. Multivariate statistical methods were applied in a graded approach to the SIMS microbial data. The results showed that the full data set could initially be statistically grouped based upon major differences in biochemical composition of the cell wall. The gram-positive bacteria were further statistically analyzed, followed by final analysis of a specific bacterial genus that was successfully grouped by species. Additionally, the use of SIMS to detect microbes on mineral surfaces is demonstrated by an analysis of Shewanella oneidensis on crushed hematite. The results of this study provide evidence for the potential of static SIMS to rapidly detect bacterial species based on ion fragments originating from cell membrane lipids directly from sample surfaces.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC07-99ID-13727
• OSTI ID: 912033
• Report Number(s): INEEL/JOU-02-00131; JMIMDQ; TRN: US200801%%475
• Journal Information: Journal of Microbiological Methods, Vol. 53, Issue 3; ISSN 0167-7012
• Country of Publication: United States
• Language: English

Related Subjects

99 - GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
BACTERIA
CARBOXYLIC ACIDS
CELL MEMBRANES
CELL WALL
CLEAVAGE
DETECTION
ESTERS
HEMATITE
LIPIDS
MASS SPECTROSCOPY
MICROORGANISMS
MOLECULAR BEAMS
PHOSPHOLIPIDS
SPECTRA
fatty acids
microorganisms
static secondary ion mass spectrometry