- Day 1, May 15（Wed.） Room P (Multi-purpose Hall)
Improved MALDI-MS Method for Proteotyping of Salmonella Serotype
Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been used for rapid identification of microorganisms. Recently, a mass database consisting of twelve biomarker proteins: S8, L15, L17, L21, L25, S7, superoxide dismutase (SodA), peptidylprolyl cis-trans isomerase C, Gns, YibT, YaiA and YciF, was reported for serotyping of Salmonella enterica in MALDI-MS (Applied Microbiology and Biotechnology, 2017, 101, 8557-8569). However, it had difficulty in reproducible peak detection of the biomarkers such as SodA at m/z 23000. We report here an optimized preparation for detecting the biomarkers with high sensitivity and reproducibility. As a result, the difficulty was solved especially by controlling bacterial concentration at 6×106~3×107 CFU/μL, using the supernatant of the colony suspension by centrifugation, and adding matrix additives such as methylenediphosphonic acid and N-decyl-β-D-maltopyranoside in the suspension.