Listeria monocytogenes
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ABSTRACT:
PROVIDER: PRJNA106191 | ENA |
REPOSITORIES: ENA
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Project description:Cultivation based analyses were used to determine the resistance of a set of 140 Listeria monocytogenes strains to weak organic acids. Strains of lineage I tended to exhibit greater overall resistant to four different organic acids compared to lineage II strains. Resistant strains also possessed higher survival levels following challenge to pH 2.4 compared to sensitive strains. Transcriptomic analyses were performed to determine genetic responses relevant to growth at mildly acidic conditions (pH 5.0) and to the presence of sodium diacetate. Lineage I and II strain representatives, clinical strain ATCC 19115 and food isolate FW04/0023, were found to exhibit similar transcriptomic changes when habituated to pH 5.0 in brain heart infusion broth (BHIB) relative to growth at pH 7.2 though considerably more divergent responses were detected when 21 mM sodium diacetate was present. Homogeneity in acid habituation-related gene expression was reflected in relatively homogenous SigB, PrfA, HrCA and CodY regulon expression responses. In the presence of sodium diacetate, SigB and PrfA regulon genes found to be upregulated in sigB and prfA null mutants were overall repressed but SigB dependent-gene activation was not evident. L. monocytogenes strains responses to sodium diacetate were observed in different expression trends amongst various functionally-related gene sets and in particular the expression of the PrfA, Atp, Kdp, Cob, Pdu, Eut and Dlt operons; iron transporter and heat shock-related proteins. The results suggest there is diversity in the specific responses to weak organic acids and subsequent cytosolic acidification amongst L. monocytogenes strains though the acid tolerance response itself manifests as a more conserved set of expression responses.
2008-05-29 | GSE11570 | GEO
Project description:Survival of the foodborne pathogen Listeria monocytogenes in acidic environments (e.g., stomach and low pH foods) is vital to its transmission. L. monocytogenes grows at temperatures as low as 2°C, and refrigerated, ready-to-eat foods have been sources of L. monocytogenes outbreaks. The purpose of this study was to determine whether growth at a low temperature (i.e., 7°C) affects the response of L. monocytogenes to sudden acid shock.
2011-07-01 | GSE22672 | 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: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.
2010-04-06 | GSE20367 | 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 | E-GEOD-21427 | biostudies-arrayexpress
Project description:These studies were designed to examine the acute Listeria monocytogenes transcriptional response to mammalian (porcine) bile.
2011-04-12 | GSE28507 | GEO
Project description:Survival of the foodborne pathogen Listeria monocytogenes in acidic environments (e.g., stomach and low pH foods) is vital to its transmission. L. monocytogenes grows at temperatures as low as 2M-BM-0C, and refrigerated, ready-to-eat foods have been sources of L. monocytogenes outbreaks. The purpose of this study was to determine whether growth at a low temperature (i.e., 7M-BM-0C) affects the response of L. monocytogenes to sudden acid shock. A full genome microarray was used to determine changes in L. monocytogenes 10403S gene expression after exposure to acidified brain-heart infusion (BHI; pH 3.5) for 5 or 15 min. To determine changes in gene transcription after acid treatment, separate competitive hybridizations were performed between cDNA from untreated cells (grown at 7M-BM-0C or 37M-BM-0C to log or stationary phase) and (i) cells acid treated for 5 min or (ii) cells acid treated for 15 min. For L. monocytogenes grown to log or stationary phase, competitive hybridizations were performed between total cDNA from non-acid-treated cells grown to 7M-BM-0C and non-acid-treated cells grown to 37M-BM-0C to determine baseline differences in gene transcription between growth temperatures prior to acid treatment. For each experiment, four biological replications were completed. Hybridizations were carried out with dye swapping (i.e., for each comparison, each cDNA from each condition was labeled with each dye exactly twice) to help minimize dye incorporation bias.
2011-06-30 | E-GEOD-22672 | biostudies-arrayexpress
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: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