ANYL 319 |
| Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is increasingly used to rapidly identify and classify bacterial microorganisms on the basis of unique protein biomarkers. Identification of these biomarkers, by proteomics techniques, validates and provides further information about why this technique is both robust and successful as a chemico-taxonomic classification system for bacteria. Potential applications of bacterial MALDI-TOF-MS include analysis foodborne pathogens to increase food safety and security. We have extracted and identified, by proteomic techniques, several MALDI-TOF protein biomarkers of Campylobacter (an important foodborne pathogen) including C. coli, C. upsaliensis, C. lari and C. helveticus strains. The significant findings are as follows. 1. MALDI-TOF biomarker mass "shifts" observed between species and strains are due to amino acid substitutions of the primary polypeptide sequence and thus reflect the underlying genetic variations between species and strains; 2. If present, a post-translational modification of a biomarker appeared consistently for all species and strains of Campylobacter; 3. It was discovered that a few protein biomarkers of Campylobacter appear to violate the N-Met cleavage rule of bacterial proteins which predicts N-Met cleavage if the penultimate residue is threonine. 4. Detection and identification of Campylobacter protein biomarkers by pattern recognition and/or bioinformatics algorithms easily speciates and even sub-speciates this microorganism. |
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Analytical Approaches: Mass Spectrometry
8:30 AM-11:20 AM, Thursday, 14 September 2006 Moscone Center -- Room 124, Oral
Division of Analytical Chemistry |