Expression profile of a parent and M-bM-^HM-^FlstC strain in regular and high salt conditions
Ontology highlight
ABSTRACT:
ORGANISM(S): Listeria monocytogenes
SUBMITTER: Atin Datta
PROVIDER: E-GEOD-56828 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Microarray analysis of the expression profiles of a parent and its derived ∆lstC mutant in normal and high salt conditions. The analysis was performed to determine which genes were altered in the mutant when grown in high salt conditions relative to the parent strain.
2014-04-16 | GSE56828 | GEO
Project description:A previously described low-fitness, high stress-resistant, variant of Listeria monocytogenes LO28 WT was subjected to an experimental evolution regime, selecting (in two parallel lines) for increased fitness in unstressed conditions. Evolved variants with increased fitness reverted to WT-like stress resistance. Whole genome sequencing and proteomics were used to identify differences between the ancestral and evolved strains.
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Project description:Bacteroidaceae are common gut microbiota members in all warm-blooded animals. However, if Bacteroidaceae are to be used as probiotics, the species selected for different hosts should reflect the natural distribution. In this study, we therefore evaluated host adaptation of bacterial species belonging to the family Bacteroidaceae. B. dorei, B. uniformis, B. xylanisolvens, B. ovatus, B. clarus, B. thetaiotaomicron and B. vulgatus represented human-adapted species while B. gallinaceum, B. caecigallinarum, B. mediterraneensis, B. caecicola, M. massiliensis, B. plebeius and B. coprocola were commonly detected in chicken but not human gut microbiota. There were 29 genes which were present in all human-adapted Bacteroides but absent from the genomes of all chicken isolates and these included genes required for the pentose cycle, and glutamate or histidine metabolism. These genes were expressed during an in vitro competitive assay, in which human-adapted Bacteroides species overgrew the chicken adapted isolates. Not a single gene specific for the chicken-adapted species was found. Instead, chicken adapted species exhibited signs of frequent horizontal gene transfer, of KUP, linA and sugE genes in particular. The differences in host adaptation should be considered when the new generation of probiotics for humans or chickens is designed.
2020-09-28 | PXD020954 | Pride
Project description:Comparison of Listeria monocytogenes transcripts in different growth conditions (exponential phase 37 degrees C, stationary phase 37 degrees C, exponential phase 30 degrees C, hypoxia, human blood, murine intestinal lumen) and different mutant strains (wild-type versus prfA, sigB and hfq deletion mutants).
2009-04-24 | E-MEXP-2142 | biostudies-arrayexpress
Project description:Comparison of Listeria monocyotgenes gene expression in different growth conditions (exponential phase 37 degrees C, stationary phase 37 degrees C, exponential phase 30 degrees C, hypoxia, human blood, murine intestinal lumen) and different mutant strains (wild-type versus prfA, sigB and hfq deletion mutants).
2010-04-16 | E-MEXP-2138 | 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. A reference design was used to analyze gene expression differences. Exponential phase cultures at 37C and at 7C were used as a reference for salt stressed samples at each temperature. Salt stressed samples from the same relative time point were compared across temperatures. 4 biological replicates were tested for each comparison.
2011-07-01 | E-GEOD-27521 | biostudies-arrayexpress
Project description:The extensively studied intracellular pathogen, L. monocytogenes, is an ideal model for identifying small-molecule agents for treating bacterial infections. By selecting specific biological targets in L. monocytogenes, which are common to Gram-positive pathogens, we could extrapolate drug discovery information derived from this well-studied bacterium. Attenuating the pathogenM-bM-^@M-^Ys virulence and stress response attributes without killing it, eliminates selective pressure caused by disruption of essential gene functions (as done by current antibiotics) and reduces the likelihood of developing microbes that are impervious to the effects of antibiotics. To this end, we have assessed multiple libraries of small organic compounds to identify inhibitors of L. monocytogenes M-OM-^CB, the alternative sigma factor common to several clinically relevant Gram-positive pathogens, such as Staphylococcus aureus, Bacillus cereus, and Bacillus anthracis. The role of M-OM-^CB as a transcriptional regulator of stress response and virulence makes it an ideal, well conserved target for chemotherapeutic development. Independent RNA isolations were performed for each growth experiment (log phase cells exposed to BHI+0.3M NaCl and BHI+0.3M NaCl + CMPD). Four biological replicates were used in competitive whole-genome microarray experiments. For the hybridizations, RNA from the wildtype parent strain L. monocytogenes 10403S were hybridized to RNA from the wildtype parent strain 10403S treated with CMPD.
2011-12-06 | E-GEOD-16887 | biostudies-arrayexpress
Project description:Aggregatibacter actinomycetemcomitans (Aa) is a Gram-negative bacterial pathogen associated with severe periodontitis and non-oral diseases. Clinical isolates of Aa display a rough (R) colony phenotype with strong adherent properties. Upon prolonged culturing, non-adherent strains with a smooth (S) colony phenotype emerge. To date, most virulence studies on Aa have been performed with S strains of Aa, whereas the virulence of clinical R isolates received relatively little attention. Since the extracellular proteome is the main bacterial reservoir of virulence factors, the present study was aimed at a comparative analysis of this sub-proteome fraction for a collection of R isolates and derivative S strains, in order to link particular proteins to the virulence of Aa with serotype b. To assess the bacterial virulence, we applied different infection models based on larvae of the greater wax moth Galleria mellonella, a human salivary gland-derived epithelial cell line, and freshly isolated neutrophils from healthy human volunteers. A total number of 351 extracellular Aa proteins was identified by mass spectrometry, with the S strains consistently showing more extracellular proteins than their parental R isolates. A total of 50 known extracellular virulence factors was identified, of which 15 were expressed by all investigated bacteria. Importantly, the comparison of differences in exoproteome composition and virulence highlights critical roles of 10 extracellular proteins in the different infection models. Altogether, our present study provides novel cues for understanding the virulence of Aa, and for development of potential preventive or therapeutic avenues to neutralize this important oral pathogen.
2022-06-01 | PXD028940 | Pride
Project description:Here, we report genome sequences of the two bioluminescent S. aureus strains Xen31 and Xen36, obtained from PerkinElmer (#119242 and #119243, respectively). Xen31 was derived from the parental MRSA strain ATCC33591, a clinical strain isolated at Elmhurst Hospital in New York City. Xen36 was derived from parental strain ATCC 49525, a clinical isolate from a bacteremic patient. A copy of the modified luxABCDE operon from Photorhadbus luminescenst is integrated in the chromosome of Xen31 and in a native plasmid of Xen36.
2022-12-14 | E-MTAB-12210 | biostudies-arrayexpress
Project description:Listeria monocytogenes is well known to have the ability to survive and grow under a variety of stress conditions. The ability to survive and grow under osmotic stress conditions in particular appears to be important for both growth in certain foods and food associated environments as well as for host infection. To characterize the contributions of transcriptional regulators important for stress response and virulence (i.e., Sigma B - M-OM-^CB and PrfA), we initially analyzed three L. monocytogenes parent strains and isogenic mutants ( delta sigB, delta prfA, and delta sigB delta prfA), representing different serotypes and lineages, for their ability to grow in BHI with 11% NaCl (1.9M) at 25M-BM-0C. No significant differences were observed in terms of growth between the parent strains and their respective mutants lacking prfA (i.e. delta prfA, and delta sigB delta prfA mutant strains). While for all strains, the delta sigB mutant showed a prolonged lag phase as compared to the parent strains, maximum growth rates were only reduced for the delta sigB mutant of lineage I and IV strains. Interestingly, for the serotype 1/2b strain, the delta sigB mutant reached a higher maximum cell density than the parent strain or the delta prfA mutant. Caco-2 intestinal epithelial cells invasion assays and hemolytic activity assays showed a significant role for M-OM-^CB in the former and for PrfA in the latter. To initially explore the mechanism that may contribute to the extended lag phase in the delta sigB mutant, microarray was performed to compare transcript levels between the lineage I, serotype 1/2b, parent strain and its isogenic delta sigB mutant in lag phase at 25M-BM-0C in the presence of 11% NaCl. Microarray data showed significant lower and higher transcript levels for 135 and 173 genes, respectively, in the parent strain as compared to the delta sigB strains. Overall, 51 of the 173 M-OM-^CB up-regulated genes had previously been found among the 249 M-OM-^CB-dependent genes identified in a microarray study conducted in stationary phase cells, indicating that up to 122 genes may be transcribed in a M-OM-^CB-dependent manner during lag phase under salt stress. Notable genes that showed higher transcript levels in the parent strain include inlD (encoding an internalin protein that may be involved in virulence), sigH (encoding an alternative M-OM-^C factor), glpK (encoding a glycerol kinase) and resD (encoding a two-component response regulator ResD); while, genes that showed lower transcript levels in the parent strain include dnaK (encoding a dihydroxyacetone kinase), groES (encoding a class I heat-shock protein GroES), grpE (encoding a co-chaperone GrpE) and fri (encoding a non-heme iron-binding ferritin). These data showed that although PrfA does not contribute to growth under osmotic stress at 25M-BM-0C, M-OM-^CB does contribute to survival of L. monocytogenes under high salt conditions. Moreover, the M-OM-^CB-dependent transcriptome of L. monocytogenes lag phase cells under salt stress was characterized and includes previously identified as well as novel M-OM-^CB-dependent genes, including a number of stress response and virulence-associated genes. Independent RNA isolations were performed for one wildtype (lineage I) and M-NM-^TsigB strains from cells grown to lag 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.
2013-07-20 | E-GEOD-49056 | biostudies-arrayexpress