Comparative Analysis of Extracellular and Intracellular Proteomes ofListeria monocytogenesStrains Reveals a Correlation between Protein Expression and Serovar

Abstract

Listeria monocytogenes, the etiologic agent of listeriosis, remains a serious public health concern, with its frequent occurrence in food environments coupled with a high mortality rate. Among the 13 serovars, human listeriosis is mostly associated with the serovar 4b, 1/2b, and 1/2a strains. To investigate the diversity of L. monocytogenes, the intracellular and extracellular proteins of 12 strains were analyzed by two-dimensional gel electrophoresis. These strains had different origins, belonged to different serovars (4b, 1/2a, and 1/2b), and presented with different levels of virulence in chicken embryos. The clustering of the strains in two groups based on proteomic patterns is in agreement with the L. monocytogenes phylogenetic lineages. Statistical analysis did not allow for identification of proteins specific to the isolate origin or the virulence level of the strains, but 26 and 21 protein spots were shown to be significantly overexpressed and underexpressed, respectively, in the six strains of serovar 1/2a (lineage II) compared to strains of serovar 1/2b or 4b. Moreover, a penicillin-binding protein was specific for serovar 1/2b and two protein spots identified as a serine protease were specific to serovar 4b. These protein spots, identified through peptide mass fingerprinting using matrixassisted laser desorption ionization-time of flight mass spectrometry, were essentially found in the extracellular proteome and may have uses as potential markers for serotyping and risk analysis.

Listeria monocytogenes lineages: Genomics, evolution, ecology, and phenotypic characteristics

“…This study not only identified genes that differed between strains with regard to B dependence of their transcription, but also found that B contributed significantly to acid and oxidative stress survival and Caco-2 cell invasion in lineage I, II, and III strains, but not in the lineage IV strain (Oliver et al, 2010). A proteomics study comparing strains from serotypes 1/2a (lineage II), 1/2b, and 4b (lineage I) found 26 proteins overexpressed in 1/2a strains as compared to the other strains while 20 other proteins were underexpressed in the 1/2a strains (Dumas et al, 2008), further supporting that L. monocytogenes lineages differ in their gene expression patterns. Overall, most differences in gene expression between lineages I and II strains found so far are associated with stress response regulation.…”

Identification of Surface Protein Biomarkers of Listeria monocytogenes via Bioinformatics and Antibody-Based Protein Detection Tools

“…The differences in reactivity observed between lineages may also be attributed to differential expression of LMOf2365_0639 between lineages. A proteomic study of several L. monocytogenes isolates of various serotypes reported that total surface protein patterns of isolates can be grouped by lineage classification (35). In addition, while the epitope recognized by M3643 is identical between sequenced L. monocytogenes isolates and other Listeria species isolates, M3643 was highly specific to L. monocytogenes cultured in BHI.…”

Comparison of Listeria monocytogenes Exoproteomes from Biofilm and Planktonic State: Lmo2504, a Protein Associated with Biofilms

“…The same effect has been verified by other authors. Dumas et al (15) stated that PlcB and InlC from L. monocytogenes were present in five and four spots, respectively, with different pIs and relative molecular weights (M r s). These authors explained this effect by the possible presence of protein orthologues with different M r s, pIs, and/or posttranslational modifications (isoforms).…”