Open AccessIdentification and Typing of Lactococcus lactis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry
Author(s) -
Keiichiro Tanigawa,
Hiroaki Kawabata,
Koichi Watanabe
Publication year - 2010
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.02698-09
Subject(s) - lactococcus lactis , subspecies , biology , 16s ribosomal rna , mass spectrometry , ribosomal rna , microbiology and biotechnology , lactococcus , proteomics , matrix assisted laser desorption/ionization , typing , bacteria , genetics , chemistry , chromatography , gene , desorption , lactic acid , paleontology , organic chemistry , adsorption
Currently, the genusLactococcus is classified into six species:Lactococcus chungangensis ,L. garvieae ,L. lactis ,L. piscium ,L. plantarum , andL. raffinolactis . Among these six species,L. lactis is especially important because of its use in the manufacture of probiotic dairy products.L. lactis consists of three subspecies:L. lactis subsp.cremoris ,L. lactis subsp.hordniae , andL. lactis subsp.lactis . However, these subspecies have not yet been reliably discriminated. To date, mainly phenotypic identification has been used, with a few genotypic identifications. We discriminated species or subspecies in the genusLactococcus not only by proteomics identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) but also by phenotypic and genotypic identification. The proteomics identification using differences in the mass spectra of ribosomal proteins was nearly identical to that by genotypic identification (i.e., by analyses of 16S rRNA andrecA gene sequences and amplified fragment length polymorphism). The three ribosomal subunits 30S/L31, 50S/L31, and 50S/L35 were the best markers for discriminatingL. lactis subsp.cremoris fromL. lactis subsp.lactis . Proteomics identification using MALDI-TOF MS was therefore a powerful method for discriminating and identifying these bacteria. In addition, this method was faster and more reliable than others that we examined.