Listeria monocytogenes
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PROVIDER: PRJNA907835 | ENA |
REPOSITORIES: ENA
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Project description:The foodborne pathogen Listeria monocytogenes uses a number of transcriptional regulators, including the negative regulator HrcA, to control gene expression under different environmental conditions and in response to stress. Gene expression patterns of DhrcA stationary phase cells were compared to wt to identify hrcA-dependent genes. We identified 61 HrcA-dependent genes that showed significant expression ratios (adj. P < 0.05), with ≥ 1.5-fold differential expression between ΔhrcA and wt. Combined with microarray analysis, Hidden Markov Model searches show HrcA directly repress at least 8 genes. Keywords: Listeria monocytogenes, HrcA regulon, stationary phase
2007-11-03 | GSE7517 | GEO
Project description:The foodborne pathogen Listeria monocytogenes uses a number of transcriptional regulators, including the negative regulator CtsR, to control gene expression under different environmental conditions and in response to stress. Gene expression patterns of DctsR log phase cells were compared to both wt and ictsR-mcsA log phase cells grown with 0.5mM IPTG to identify CtsR-dependent genes.We identified 62 CtsR-dependent genes that showed significant expression ratios (adj. P < 0.05), with ≥ 1.5-fold differential expression either between ΔctsR and wt or between ΔctsR and ictsR-mcsA. Keywords: Listeria monocytogenes, CtsR regulon, log phase
2007-10-14 | GSE7514 | GEO
Project description:Listeria monocytogenes is the ubiquitous food-borne pathogen which causes listeriosis, a disease with a high mortality rate, mostly transmitted through contaminated ready-to-eat foods (EFSA, 2018). To better understand the systemic response of such microorganism exposed at three environmental factors (T, pH and NaCl), the proteome of a L. monocytogenes strain, which was isolated from a meat product (Coppa di testa) linked to a listeriosis outbreak occurred in Marche region (Italy) in 2016, was investigated in order to identify differences in its protein patterns.
2022-08-12 | PXD033519 | Pride
Project description:Listeria monocytogenes cells (strain LI0521) were digested with trypsin for the identification of surface proteins. The supernatant was filter-sterilized and subjected to identification by LC-MS/MS. Concurrently secreted or shed proteins were identified by isolating filter-sterilized supernatants following incubation of L. monocytogenes cells in buffer without trypsin. This was followed by trypsin digest of the sterilized supernatant and identification by LC-MS/MS.
2013-08-27 | PXD000035 | Pride
Project description:In several gram-positive bacterial genera including Bacillus, Staphylococcus, and Listeria, sigma B (σB) has been identified as a stress-responsive alternative sigma factor responsible for initiating transcription of genes (the σB regulon) involved in response to stress-inducing environmental conditions. In L. monocytogenes, a foodborne pathogen of considerable threat to public health and the food industry, σB is involved in regulation of stress response and virulence gene expression. We have defined the σB regulon in L. monocytogenes during early stationary phase and under salt stress (0.3M NaCl) conditions using whole-genome microarrays, identifying 168 genes that generated ≥2.0-fold higher signals in the parental strain 10403S than in an isogenic sigB null mutant (ΔsigB), categorized into nine functional groups including stress-response genes (12), virulence genes (5), and genes related to transport (26) and metabolism (45). To gain a broader biological perspective of the σB stress response system, we applied these microarrays to Listeria innocua under the same environmental conditions. Our studies revealed 64 candidates in the L. innocua σB regulon with ≥2.0-fold higher signals in the parent than in a ΔsigB mutant; 49 of the 64 genes overlap with the L. monocytogenes σB regulon, indicating extensive overlap in σB-controlled genes between the two species. Further transcriptional analysis using TaqMan quantitative real time RT-PCR was performed for selected genes that displayed contrasting fold changes among the four microarray data sets (two stress conditions per species). We report novel members of the L. monocytogenes σB regulon, as well as the initial definition of the L. innocua σB regulon. Our comparative studies of the σB stress response systems in L. monocytogenes and L. innocua revealed features of the σB regulon that are conserved and unique to the two species. Keywords: Listeria monocytogenes, Listeria innocua, SigB regulon, salt stress, stationary phase
2007-11-29 | GSE7492 | GEO
Project description:Listeria monocytogenes from food industry
| PRJNA689484 | ENA
Project description:Peracetic acid (PAA), a strong oxidizing agent, has been widely used as a disinfectant in food processing settings as it does not produce harmful chlorinated by-products. In the present study, the transcriptional response of Listeria monocytogenes to 2.5 ppm of PAA was assessed using RNA-sequencing (RNA-seq). Our analysis revealed 12 differentially expressed genes, of which 9 were up-regulated (ohrR, ohrA, rpsN, lmo0637, lmo1973, fur, lmo2492, zurM, and lmo1007), and 3 were down-regulated (argG, lmo0604, lmo2156) in PAA treated samples compared to the control samples. A non-coding small RNA (rli32) was also found to be down-regulated. In detail, the organic peroxide toxicity protection (OhrA-OhrR) system, the metal homeostasis genes fur and zurM, the SbrE-regulated lmo0636-lmo0637 operon and a carbohydrate phosphotransferase system (PTS) operon component were induced under exposure of L. monocytogenes to PAA. Hence, this study identified key elements involved in the primary response of L. monocytogenes to oxidative stress caused by PAA. The investigation of the molecular mechanism of PAA response in L. monocytogenes is of utmost importance for the food industry, as this response can be induced in food-processing environments, as a result of inadequate rinsing during the disinfection process, that lead to PAA residues at low concentrations.
2024-10-04 | GSE269393 | GEO
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: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. This is a Listeria monocytogenes pan-genome tilling array designed using PanArray algorithm. 9 experimental strains (F2-569, M1-002, F2-208, J2-071, J1-208, W1-111, W1-110, F2-524, F2-501) vs reference (EGD-e) strain.
2010-04-06 | E-GEOD-20367 | biostudies-arrayexpress
Project description:The SOS response is a conserved pathway that is activated under certain stress conditions and is regulated by the repressor LexA and the activator RecA. The food-borne pathogen Listeria monocytogenes contains RecA and LexA homologs, but their roles in Listeria have not been established. In this study, we identified the SOS regulon in L. monocytogenes by comparing the transcription profiles of the wild-type strain and the ΔrecA mutant strain after exposure to the DNA damaging agent mitomycinC (MMC). The SOS response is an inducible pathway involved in DNA repair, restart of stalled replication forks, and in induction of genetic variation in stressed and stationary phase cells. It is regulated by LexA and RecA. LexA is an autoregulatory repressor which binds to a consensus sequence in the promoter region of the SOS response genes, thereby repressing transcription. A consensus LexA binding motif for L. monocytogenes has not been identified thus far. Generally, the SOS response is induced under circumstances in which single stranded DNA accumulates in the cell. This results in activation of RecA, which in turn stimulates cleavage of LexA, and ultimately in the induction of the SOS response. Keywords: stress response, loop design, SOS response, mitomycin c, listeria monocytogenes, RecA, LexA
2009-11-25 | GSE12634 | GEO