Listeria monocytogenes
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ABSTRACT:
PROVIDER: PRJNA808240 | ENA |
REPOSITORIES: ENA
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Project description:Genetic analysis of Lm isolated from Japanese seafood
| PRJDB6714 | ENA
Project description:IFN-Is have a detrimental effect in the case of Listeria monocyteogenes (Lm) infection. Previously it has been shown that Ifnar-/- mice are protected from the infection induced death. However, we have found that IRF9, a downstream component of the IFNAR signalling, has a role in addition to the IFNAR signalling in protecting the mice from Lm infection. This is due to Irf9-/- mice being more protected than Ifnar-/- mice. Among other hypotheses, we think that the recently shown role of Irf9 in glucose metabolism can be effective in this additional protection. Furthermore, our metabolic screens point to similar direction. Therefore, we would like to measure the differential gene expression pattern in livers from uninfected and 1 day infected Wt, Irf9-/- and Ifnar-/- mice.
2021-06-09 | GSE162448 | GEO
Project description:Cerebral listeriosis is characterized by neuronal apoptosis and microglial cell activation, but little is known about the bacterial virulence factors involved in this process and how bacterial dissemination is controlled. Here, we show that the cellular target of Listeria monocytogenes (LM) in murine hippocampal cultures is microglia rather than neurons or other glial cells, which are rarely infected. This in vitro model served to demonstrate that infected microglial cells release a soluble factor to the medium responsible for neuronal apoptosis. We investigated the production of this factor in a well-established murine microglia cell model BV2 cells, and compared with J-774 macrophage cells after infection with different LM bacterial mutants. Our purpose was to study in both cell types parameters such as the listericidal capacities, pro-inflammatory cytokines released, and bacterial factors involved in the intracellular cycle. Our data reveal that microglia shows unique features to handle a LM infection. Microglia is three times more permissive for LM intracellular growth than murine macrophages; while producing five times higher levels of pro-inflammatory cytokines IL-6, MCP-1 and TNF-α than macrophages. Using different LM mutants (i.e., LMWT, LM∆LLO, LM∆ActA or LM∆plcB) we conclude that LLO and ActA are not involved in LM proliferation within microglia cells, while they are required for survival within macrophages. Moreover, ActA controls TNF-α production, a cytokine involved in neural apoptosis. Transcriptional differential response of microglia infected with different LM mutants reflected ActA controls the TNF-a signaling pathway through out molecules and chemokines involved in this pathway such as NFkβ, MAPK-1, Ccl2, Ccl3, Ccl4 and CxCl10.
2011-10-03 | GSE32505 | GEO
Project description:Full title: Probing the pan genome of a foodborne bacterial pathogen Listeria monocytogenes: Implications for its niche adaptation, pathogenesis, and evolution Listeria monocytogenes is a foodborne bacterial pathogen well known for adaptability to diverse environmental and host niches, and a high fatality rate among infected, immuno-compromised individuals. Three genetic lineages have been identified within this species. Strains of genetic lineages I and II account for more than ninety percent of foodborne disease outbreaks worldwide, whereas strains from genetic lineage III are rarely implicated in human infectious for unknown, yet intriguing, reasons. Here we have probed the genomic diversity of 26 L. monocytogenes strains using both whole-genome sequences and a novel 385,000 probe pan-genome microarray, fully tiling the genomes of 20 representative strains. Using these methods to identify genes highly conserved in lineages I and II but rare in lineage III, we have identified 86 genes and 8 small RNAs that play roles in bacterial stress resistance, pathogenicity, and niche, potentially explaining the predominance of L. monocytogenes lineages I and II in foodborne disease outbreaks. Extending gene content analysis to all lineages revealed a L. monocytogenes core genome of approximately 2,350 genes (80% of each individual genome) and a pan-genomic reservoir of >4,000 unique genes. Combined gene content data from both sequences and arrays was used to reconstruct an informative phylogeny for the L. monocytogenes species that confirms three distinct lineages and describes the relationship of 9 new lineage III genomes. Comparative analysis of 18 fully sequenced L. monocytogenes lineage I and II genomes shows a high level of genomic conservation and synteny, indicative of a closed pan-genome, with moderate domain shuffling and sequence drift associated with bacteriophages is present in all lineages. In contrast with lineages I and II, notable genomic diversity and characteristics of an open pan-genome were observed in the lineage III genomes, including many strain-specific genes and a more complex conservation pattern. This indicates that the L. monocytogenes pan-genome has not yet been fully sampled by genome sequencing, and additional sequencing of lineage III genomes is necessary to survey the full diversity of this intriguing species and reveal its mechanisms for adaptability and virulence.
2010-04-06 | GSE20367 | GEO
Project description:Listeria monocytogenes LM:43 Genome sequencing and assembly
| PRJNA692333 | ENA
Project description:Listeria monocytogenes strains classify into at least three distinct phylogenetic lineages. Correlations exist between lineage classification and source of bacterial isolation, e.g., human clinical and food isolates usually classify into either lineage I or II, however, human clinical isolates are over-represented in lineage I while food isolates are over-represented in lineage II. σB, a transcriptional regulator previously demonstrated to contribute to environmental stress response and virulence in L. monocytogenes lineage II strains, was hypothesized to provide differential capabilities for L. monocytogenes survival in various niches (e.g., food vs. human clinical). To determine if σB contributions to stress response and virulence differ across diverse L. monocytogenes strains, ΔsigB mutations were created in strains from lineages I, II, IIIA, and IIIB. Paired parent and ΔsigB mutant strains were tested for acid and oxidative stress survival, Caco-2 cell invasion efficiency, and virulence using the guinea pig listeriosis infection model. Parent and ΔsigB mutant strain transcriptomes were compared using whole-genome expression microarrays. σB contributed to virulence in each strain. However, while σB contributed significantly to acid and oxidative stress survival and Caco-2 cell invasion in lineage I, II, and IIIB strains, σB contributions were not significant for these phenotypes in the lineage IIIA strain. A core set of 63 genes was positively regulated by σB in all four strains; different total numbers of genes were positively regulated by σB in each strain. Our results suggest that σB universally contributes to L. monocytogenes virulence, but specific σB-regulated stress response phenotypes vary among strains.
2010-06-01 | GSE21427 | GEO
Project description:The foodborne pathogen Listeria monocytogenes (Lm) can cause invasive infection in susceptible animals and humans. To survive and proliferate within hosts, this facultative intracellular pathogen needs to tightly coordinate the expression of a complex regulatory network, including virulence factors. Here, we identify and characterize MouR a novel virulence regulator of Lm. Through RNA-seq transcriptomic analysis, we characterized the MouR regulatory network and demonstrated how MouR positively controls the expression of the Agr system (agrBDCA) of Lm. Resolving MouR 3D structure revealed a dimeric DNA-binding transcription factor belonging to the VanR class of the GntR superfamily of regulatory proteins. We showed that by direct binding to the agr promoter region, MouR ultimately modulates chitinase activity and biofilm formation. Importantly, we demonstrated by in vitro cell invasion assays and in vivo mice infections the crucial role of MouR for Lm full virulence.
2018-10-22 | GSE106833 | GEO
Project description:Complete sequencing (PacBio) and de novo genome assembly of selected Listeria reference strains and isolates for proteogenomics studies
| PRJNA413700 | ENA
Project description:Listeria monocytogenes (Lm) kills up to 60% of infected newborns and adults >60 years of age but is asymptomic is most young adults. Monocytes are central to effective host defense against Lm. We hypothesize that age-dependent, pathway-specific differences in the ability of the monocyte to respond to Lm explain the increased risk of the newborn and older adult to severely suffer or die from Lm infection. To delineate age-dependent differences in innate responses that lead to differential infectious outcome, monocytes were isolated from cord blood (newborn) and peripheral blood (young and older adults) and infected with Lm. RNA was collected to determine age-dependent transcriptomic changes upon infection.
2015-09-01 | GSE67983 | GEO