Project description:Listeria monocytogenes is an opportunistic foodborne pathogen responsible for listeriosis, the third most common foodborne disease. Many different Listeria strains and seroptypes exist, however a proteogenomic resource which would provide a basis for bridging the gap in the molecular understanding between the Listeria genotype and phenotypes via proteotypes is still missing. Here we devised a next-generation proteogenomics strategy which enables the community now to rapidly proteotype Listeria strains and relate the information back to the genotype. Based on sequencing and de novo assembly of the two most commonly used Listeria strain model systems, EGD-e and ScottA, we established a comprehensive Listeria proteogenomic database. A genome comparison established core and strain-specific genes with potential relevance for virulence differences. Next we established a DIA/SWATH-based proteotyping strategy, including a new and robust sample preparation workflow, enabling the reproducible, sensitive and relative quantitative measurement of Listeria proteotypes. This re-usable DIA/SWATH library and new public resource covers 70% of the potentially expressed ORFs of Listeria and represents the most extensive spectral library for Listeria proteotype analysis to date. We used these two new resources to investigate the Listeria proteotype in three states mimicking the upper gastrointestinal passage. Exposure of Listeria to bile salts at 37 °C, mimicking conditions encountered in the duodenum, showed significant proteotype perturbations including an increase of FlaA, the structural protein of flagella. Given that Listeria is known to lose its flagella above 30 °C, this was an unexpected finding. The formation of flagella, which might have implications within the infectivity cycle, was validated by parallel reaction monitoring, light and scanning electron microscopy. QPCR data of flaA transcripts showed no significant differences suggesting a regulation at the post-transcriptional level. Together, we provide a comprehensive proteogenomic resource and toolbox for the Listeria community enabling the analysis of Listeria genotype-proteotype-phenotype relationships.
Project description:Comparisons of gene expression profiles of human hepatocytes (Huh7) infected or not by the bacterium Listeria monocytogenes (strain EGD-e) for 72 hours and analysed by RNA-seq
Project description:Comparisons of gene expression profiles of human hepatocytes (HepG2) infected or not by the bacterium Listeria monocytogenes (strain EGD-e) for 72 hours and analysed by RNA-seq
Project description:Phosphopeptides were identified in Listeria monocytogesn strain constitutivally expressing PrfA. Also, the phosphoproteins and proteins were identified that are overexpressed/underextressed in response to PrfA.
Project description:Comparisons of gene expression profiles PMH infected or not by the bacterium Listeria monocytogenes (strain 10403S) for 72 hours and analysed by RNA-seq
Project description:Listeria monocytogenes strain F2365 was the first strain representative of serotype 4b (lineage I) to be sequenced in 2004, suggesting it could become the model organism for this serotype, which is associated with most human outbreaks of listeriosis worldwide to date. F2365 itself is an outbreak strain involved in the Mexican-style soft cheese outbreak in California in 1985. In this study we show through phenotypic and transcriptomic analysis that L. monocytogenes strain F2365 has reduced ability to respond to stress due to the absence of a functional σB-dependent stress response system. F2365 shows no B-dependent ability to survive acid or oxidative stress nor B-dependent ability to infect Caco-2 epithelial cell in vitro or guinea pigs in vivo. Therefore, there is substantial evidence that F2365 is an atypical strain and is not a suitable representative of outbreak-associated serotype 4b strains.