Listeria monocytogenes
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PROVIDER: PRJNA122461 | ENA |
REPOSITORIES: ENA
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Project description:Gene expression profiles of L. monocytogenes strain F2365 to osmotic stress was examined. Based on a log2 scale, four and 24 genes were upregulated and downregulated by the stress, respectively.The expression level of ATP-binding cassette superfamily and ribosomal protein L2 genes were increased, whereas genes associated with PTS system, its metabolic enzymes, pathogenesis, and hypothetical protein were downregulated. To examine the gene expression profiles of L. monocytogenes grown in the medium added with or without 1.2% NaCl , L. monocytogenes strains 4b F2365 aminosilane-coated cDNA microarray slide was used. Cy3 and Cy5 dyes were used for cDNA labelling. Data were obtained from three biological and four technical replicates (n = 12). Each biological replicate included a flip dye assay.
2010-05-15 | E-GEOD-19570 | biostudies-arrayexpress
Project description:The organic acids lactate and diacetate are commonly used in combination in ready-to-eat foods because they show synergistic, i.e. greater than additive, ability to inhibit the growth of Listeria monocytogenes. Full genome microarrays were used to investigate the synergistic transcriptomic response of two L. monocytogenes strains, h7858 (serotype 4b) and f6854 (serotype 1/2a), to organic acid, under conditions controlling for osmotic and cold stress. Strains were exposed to BHI broth at 7°C with 4.65% water phase (w.p.) NaCl at pH 6.1 treated with 2% w.p. potassium lactate, 0.14% w.p. sodium diacetate, the combination of both at the same levels, or no inhibitors as control. RNA was extracted 8h after exposure, during lag phase, to capture gene expression changes during adaptation to the organic acid stress. Treatment with organic acids induced massive global transcriptional changes, with 1041 and 640 genes differentially expressed in h7858 and f6854. Major effects of treatment with lactate and diacetate are (i) a total of 474 and 209 genes, for h7858 and f6854, that showed synergistic expression differences, (ii) differential expression of membrane ion transport genes including those encoding ABC transporters of metals and decreased multi-drug transporter expression many ABC, PTS, and drug transporter systems, including increased PTS sugar transport and decreased multi-drug transporter expression, and (iii) altered metabolism including induction of a nutrient limiting stress response, reduction of menaquinone biosynthesis, and a shift from fermentative production of lactate and acetate and lactate to energetically less favorable, neutral acetoin. These data suggest that additional synergies in L. monocytogenes growth inhibition could be achieved by treatments that interfere with cellular energy generation processes.
2011-11-03 | GSE25195 | GEO
Project description:Transcriptional profile of wild type L. monocytogenes (EGDe) and a pycA mutant strain was compared on growth in BHI. The human pathogen L. monocytogenes is a facultatively intracellular bacterium that survives and replicates in the cytosol of many mammalian cells. The listerial metabolism, especially under intracellular conditions , is still poorly understood. Recent studies analyzed the carbon metabolism of L. monocytogenes by the 13C-isotopologue perturbation method in a defined minimal medium containing [U-13C6]glucose. It was shown that these bacteria produce oxaloacetate mainly by carboxylation of pyruvate due to an incomplete tricarboxylic acid cycle. Here we report that a pycA insertion mutant defective in pyruvate carboxylase (PYC) still grows, albeit at a reduced rate, in BHI medium, but is unable to multiply in a defined minimal medium with glucose or glycerol 36 as carbon source. Transcriptional profiling was performed on the pycA mutant and the wild type strain grown in BHI to get a closer insight into the effect of the pycA mutation in Listeria monocytogenes.
2010-02-10 | GSE19014 | GEO
Project description:The gene expression profiles of L. monocytogenes strain F2365 grown in BHI agar (reference) or on a turkey deli meat (query) was examined. Aminosilane-coated cDNA microarray slide was used. The data from the normalized ratio of query to reference signal for each spot were transformed using a log2 scale. The expression level of genes obtained from the mean of each gene on the twelve slides was considered significantly different over 1.5 fold changes. Thirty nine and forty five genes in L. monocytogenes grown on a turkey meat matrix were upregulated and downregulated, respectively. To examine the gene expression profiles of L. monocytogenes grown in BHI agar or on a turkey deli meat, L. monocytogenes strains 4b F2365 aminosilane-coated cDNA microarray slide was used. Cy3 and Cy5 dyes were used for cDNA labelling. Data were obtained from three biological and four technical replicates (n = 12). Each biological replicate included a flip dye assay. TM4 package developed by TIGR was used to analyze the data.
2010-05-14 | E-GEOD-20274 | biostudies-arrayexpress
Project description:The organic acids lactate and diacetate are commonly used in combination in ready-to-eat foods because they show synergistic, i.e. greater than additive, ability to inhibit the growth of Listeria monocytogenes. Full genome microarrays were used to investigate the synergistic transcriptomic response of two L. monocytogenes strains, h7858 (serotype 4b) and f6854 (serotype 1/2a), to organic acid, under conditions controlling for osmotic and cold stress. Strains were exposed to BHI broth at 7°C with 4.65% water phase (w.p.) NaCl at pH 6.1 treated with 2% w.p. potassium lactate, 0.14% w.p. sodium diacetate, the combination of both at the same levels, or no inhibitors as control. RNA was extracted 8h after exposure, during lag phase, to capture gene expression changes during adaptation to the organic acid stress. Treatment with organic acids induced massive global transcriptional changes, with 1041 and 640 genes differentially expressed in h7858 and f6854. Major effects of treatment with lactate and diacetate are (i) a total of 474 and 209 genes, for h7858 and f6854, that showed synergistic expression differences, (ii) differential expression of membrane ion transport genes including those encoding ABC transporters of metals and decreased multi-drug transporter expression many ABC, PTS, and drug transporter systems, including increased PTS sugar transport and decreased multi-drug transporter expression, and (iii) altered metabolism including induction of a nutrient limiting stress response, reduction of menaquinone biosynthesis, and a shift from fermentative production of lactate and acetate and lactate to energetically less favorable, neutral acetoin. These data suggest that additional synergies in L. monocytogenes growth inhibition could be achieved by treatments that interfere with cellular energy generation processes. The dye-swapped, single loop design hybridizes a single biological replicate of both 2% water phase lactate (PL) and 0.14% water phase acetate (SDA) treatments to both the control (CTRL) and combination (PLSDA) treatments (4 hybridizations), using opposite dye labels for each sample, and a second biological replicate is hybridized with dye assignments swapped (4 more hybridizations) to balance labeling effects. The design was repeated twice comprising 16 hybridizations over 4 biological replicates for each strain, and 32 total hybridizations over both h7858 and f6854.
2011-11-03 | E-GEOD-25195 | biostudies-arrayexpress
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 M-OM-^CB-dependent stress response system. F2365 shows no M-oM-^AM-3B-dependent ability to survive acid or oxidative stress nor M-oM-^AM-3B-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. Independent RNA isolations were performed for F2365 and M-NM-^TsigB strains from cells grown to early stationary phase. Three biological replicates were used in competitive whole-genome microarray experiments. For each set of hybridizations, RNA from a L. monocytogenes wildtype strain was hybridized with RNA from its isogenic M-NM-^TsigB null mutant.
2013-06-01 | E-GEOD-42730 | biostudies-arrayexpress
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.
2013-06-01 | GSE42730 | GEO
Project description:Transcriptional profile of wild type L. monocytogenes (EGDe) and a pycA mutant strain was compared on growth in BHI. The human pathogen L. monocytogenes is a facultatively intracellular bacterium that survives and replicates in the cytosol of many mammalian cells. The listerial metabolism, especially under intracellular conditions , is still poorly understood. Recent studies analyzed the carbon metabolism of L. monocytogenes by the 13C-isotopologue perturbation method in a defined minimal medium containing [U-13C6]glucose. It was shown that these bacteria produce oxaloacetate mainly by carboxylation of pyruvate due to an incomplete tricarboxylic acid cycle. Here we report that a pycA insertion mutant defective in pyruvate carboxylase (PYC) still grows, albeit at a reduced rate, in BHI medium, but is unable to multiply in a defined minimal medium with glucose or glycerol 36 as carbon source. Transcriptional profiling was performed on the pycA mutant and the wild type strain grown in BHI to get a closer insight into the effect of the pycA mutation in Listeria monocytogenes. RNA from the two strains were isolated after growth in BHI and and compared using whole genome oligonucleotide microarrays
2010-02-09 | E-GEOD-19014 | biostudies-arrayexpress
Project description:The foodborne pathogen Listeria monocytogenes experiences osmotic stress in many habitats, including foods and the gastrointestinal tract of the host. While osmotic stress induced changes in expression have been investigated for specific genes, identifying and understanding genome-wide temporal changes in the transcriptome due to salt stress will provide insights into how this pathogen adapts to and survives this stress, leading to development of new intervention strategies. To determine the short-term and long-term responses to salt stress, we exposed exponential phase cells of L. monocytogenes H7858 to 6% NaCl in Brain Heart Infusion (BHI) broth at 7°C and 37°C and extracted RNA after 2.5%, 5%, 10%, and 20% of lag phase and during exponential growth in BHI + 6% NaCl, and evaluated temporal changes in transcript levels with microarrays. The temperature dependent short-term response to salt stress included a significant increase in transcript levels of the alternative sigma factor σB, with maximum expression at 2.5-5% of lag phase at 37°C, and at 20% of lag phase at 7°C. Transcript levels of genes known to be regulated by σB, including inlAB, opuCA, glpFK, and gadBC, were significantly upregulated at the same relative time points as σB As indicated by significantly elevated transcript levels during exponential growth in BHI + 6% NaCl, genes encoding proteins involved in purine and pyrimidine synthesis and amino acid biosynthesis are part of the long-term response to salt stress at 37°C. Transcript levels of virulence genes plcA, mpl, actA, and plcB were also significantly upregulated during exponential growth under salt stress at 37°C. Genes encoding proteins involved in protein degradation and stability and cell membrane modifications are part of the long-term response to salt stress at 7°C. Overall, an initial alteration in the transcriptome occurs, decreasing transcript levels of genes encoding proteins involved in energy conversion and metabolism, while increasing transcript levels of those involved in the stress response controlled by σB, followed by a long-term response, including increased expression of genes encoding compatible solute transporters and general stress proteins, facilitating growth under salt stress.
2011-07-01 | GSE27521 | GEO
Project description:P388D1 murine macrophages were cultured in 85 mm tissue culture plates to about semi confluency. L. monocytogenes serotypes (1/2a EGD-e, 4a L99, 4b CLIP80459 and 4b F2365) were infected to the P388D1 cell monolayer at a MOI of 100 per eukaryotic cell. Infection was carried for 45 min and followed by addition of fresh medium containing 20 M-5g/ml gentamicin. The medium of the plates (containing 20 M-5g/ml gentamicin) infected with L. monocytogenes serotypes were replaced after 2 h post infection with fresh medium containing 50 M-5g/ml gentamicin. At each step the plates were washed extensively with 1x PBS. Incubation of the bacterial tissue culture plates was carried out in a humidified incubator for up to 4 h post infection.
2010-11-25 | E-MEXP-1947 | biostudies-arrayexpress