Citation:

STELMA, G. N., D. J. FLANIGAN, L. A. BOCZEK, D. J. LYE, AND M. J. DONOHUE. EXAMINATION OF THE PROTEIN PROFILE OF HELICOBACTER PYLORI UNDER DIFFERENT GROWTH CONDITIONS USING MATRIX-ASSISTED LASER DESORPTION MASS SPECTROMETRY. Presented at American Society for Microbiology 107th Meeting, Toronto, ON, CANADA, May 21 - 25, 2007.

Impact/Purpose:

This particular task is comprised of 4 subtasks: 1.) Characterization of Potential Viral Biomarkers by Mass Spectrometry; 2.) Characterization of Parasites by Mass Spectrometric Techniques;

3.) Rapid Discrimination of Bacterial Indicators of Fecal Contamination and Bacterial Pathogens by Mass Spectrometric Techniques; and 4.) Investigation of Aeromonas Virulence Factors Using Mass Spectrometry.

The purpose of this research project is to use mass spectrometric techniques, such as electrospray ionization (ESI), capillary electrophoresis (CE) and matrix assisted laser desorption ionization (MALDI) mass spectrometry, to provide "protein mass fingerprinting" and protein sequencing information for viruses, bacteria and protozoa that cause waterborne disease. These protein mass fingerprinting libraries will be evaluated to determine whether mass spectrometric techniques can identify protein fingerprints related to the infectivity/viability of selected microorganisms and whether they can differentiate between infective / non-infective genus and strains of the selected microorganisms. The characteristic proteins identified by mass spectrometry as markers of infectivity/viability or strain differentiation can then be used to develop more sensitive microbiological drinking water methods.

Description:

US EPA currently has H. pylori on its Contaminant Candidate List 2 (CCL 2), methods are needed to detect the occurrence of viable H. pylori in drinking water. H. pyloi is an interesting microorganism because it can change from a cultural and metabolically active state with a helical morphology to a non-culturable, dormant state with a coccoid morphology. There is currently no culture medium for isolating H. pyloi from drinking water. Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry

(MALDI-MS) was used to look at protein profiles of H. pyloi over the course of 10 days. After four days on blood agar, more than 50% of the H. pyloi cells were coccoid and non-culturable and a noticeable shift of protein expression was observed. This altered protein profile was continuously observed up to day 10, at which time all culturability was lost but ATP was still present. Efforts are currently focused on identifying the H. pyloi proteins observed between day 4 and day 10. We hope to use these proteins as possible markers of viability and develop more sensitive detection methods using these markers as targets.

Record Details: