Gene profiling-based phenotyping for identification of cellular parameters that contribute to fitness, stress-tolerance and virulence of Listeria monocytogenes variants
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ABSTRACT:
ORGANISM(S): Listeria monocytogenes LO28 Listeria monocytogenes
PROVIDER: GSE114672 | GEO | 2018/11/09
REPOSITORIES: GEO
Similar Datasets
Project description:To investigate whether salt-stress dependent activation of SigB is mitigated when cells are pre-loaded with the compatible solute glycine betaine, we analyzed salt induction of the SigB regulon in the presence of the precursor choline at a genome-wide level. The median expression value of SigB-regulated genes was 1.7-fold higher in cells that received choline immediately before salt stress compared to cells where choline was added 60 minutes prior to the salt stress.
2020-03-01 | GSE141882 | GEO
Project description:Adaptation to altered osmotic conditions is a fundamental property of living cells and has been studied in particular detail in the yeast Saccharomyces cerevisiae. Yeast cells accumulate glycerol as compatible solute, controlled at different levels by the High Osmolarity Glycerol (HOG) response pathway. Up to now, essentially all osmostress studies in yeast have been performed with glucose as carbon and energy source, which is metabolised by glycolysis with glycerol is as a normal by-product. Here we investigated the response of yeast to osmotic stress when yeast is respiring ethanol as carbon and energy source. Remarkably, yeast cells do not accumulate glycerol under these conditions and it appears that trehalose may partly take over the role as compatible solute. The HOG pathway is activated in very much the same way as in during growth on glucose medium and is also required for osmotic adaptation. Slower volume recovery was observed in ethanol-grown cells as compared to glucose-grown cells. Dependence on key regulators as well as the global gene expression profile were similar in many ways to those previously observed in glucose-grown cells. However, there are indications that cells re-arrange redox-metabolism when respiration is hampered under osmostress, a feature that could not be observed in glucose-grown cells.
2017-02-27 | E-MTAB-5313 | biostudies-arrayexpress
Project description:It is unclear how the amount of active nuclear MAPK over time quantitatively affects transcription. Here, we seek to address this issue by studying signal transduction and transcriptional response in a system that separates signalling from adaptation and hence signal strength from signal duration. The system is based on Saccharomyces cerevisiae osmoadaptation and allows modulation of the period of HOG-dependent responses without changing the initial stress intensity. The conditional osmotic stress system includes (i) a yeast mutant (gpd1 gpd2) unable to produce its main osmolyte glycerol, subsequently stressed with (ii) a stress inductor (polyols of different sizes) and allowed to adapt by (iii) expression of polyol flux-mediating aquaglyceroporin (rat AQP9). As there is no endogenous glycerol production, the osmoadaptation rate depends only on the size dependent equilibration rate over the plasma membrane of the polyol used as both stress inductor and compatible solute. Hence, we apply initially identical stresses but with differential durations, and determine the global transcriptional response.
2014-05-31 | GSE29716 | GEO
Project description:It is unclear how the amount of active nuclear MAPK over time quantitatively affects transcription. Here, we seek to address this issue by studying signal transduction and transcriptional response in a system that separates signalling from adaptation and hence signal strength from signal duration. The system is based on Saccharomyces cerevisiae osmoadaptation and allows modulation of the period of HOG-dependent responses without changing the initial stress intensity. The conditional osmotic stress system includes (i) a yeast mutant (gpd1 gpd2) unable to produce its main osmolyte glycerol, subsequently stressed with (ii) a stress inductor (polyols of different sizes) and allowed to adapt by (iii) expression of polyol flux-mediating aquaglyceroporin (rat AQP9). As there is no endogenous glycerol production, the osmoadaptation rate depends only on the size dependent equilibration rate over the plasma membrane of the polyol used as both stress inductor and compatible solute. Hence, we apply initially identical stresses but with differential durations, and determine the global transcriptional response. Saccharomyces cerevisiae W303-1A (MATa leu2-3/112 ura3-1 trp1-1 his3-11/15 gpd1::TRP1 gpd2::URA3) osmotically stressed with 1M of glycerol, erythritol, xylitol or sorbitol. Samples are taken in triplicates (except for sorbitol 20 an 90 min and 20 min xylitol were duplicates were taken) in time course series after stress application. Total of 45 samples. RNA from from cultures of gpd1 gpd2 cells expressing rAQP9 prior to polyol exposure was used as reference RNA for all microarrays.
2014-05-31 | E-GEOD-29716 | biostudies-arrayexpress
Project description:Global gene expression profiles of V. parahaemolyticus grown under 2% and 0.66% NaCl were compared to define the minimum low-salt stimulon. The ectABC-lysC operon for synthesis of the compatible solute ectoine, as well as three compatible-solute transport systems, namely ProU (glycine betaine), OpuD1 (glycine betaine) and Pot2 (spermidine), was up-regulated under 2% NaCl in relative to 0.66% NaCl. The 2% NaCl condition favored the inducible expression of OmpW, OmpN and OmpA2, while repressed the expression of OmpA1, OmpU and VP1008. These results indicated that, to master the hyperosmotic stress of saline environments, V. parahaemolyticus might not only accumulate osmoprotectants through uptake or endogenous synthesis of compatible solutes, but also remodel its profiles of outer membrane protein to restore its cell membrane. The above differentially regulated genes will provide novel candidates for the further investigation of the molecular mechanisms of osmoadaptation in V. parahaemolyticus.
2009-07-07 | GSE16530 | GEO
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 - σB 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 25°C. 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 σB 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 25°C 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 σB up-regulated genes had previously been found among the 249 σB-dependent genes identified in a microarray study conducted in stationary phase cells, indicating that up to 122 genes may be transcribed in a σB-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 σ 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 25°C, σB does contribute to survival of L. monocytogenes under high salt conditions. Moreover, the σB-dependent transcriptome of L. monocytogenes lag phase cells under salt stress was characterized and includes previously identified as well as novel σB-dependent genes, including a number of stress response and virulence-associated genes.
2013-07-20 | GSE49056 | GEO
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
Project description:Glycine betaine (GBT) is a component of labile dissolved organic matter and a compatible solute in high concentrations in marine microbial populations. GBT has complex biochemical potential, but, once taken up from the environment, the cellular fate of the carbon and nitrogen from GBT is unknown. Here we determine the uptake kinetics and metabolism of GBT in two natural microbial communities characterized by different nitrate concentrations in the North Pacific transition zone. Dissolved GBT had maximum uptake rates of 0.36 and 0.56 nM hr -1 and half-saturation constants of 79 and 11 nM in the high nitrate and low nitrate stations, respectively. GBT taken into cells was predominantly retained as an untransformed compatible solute. A portion of GBT was transformed into other metabolites, through characterized and uncharacterized pathways. Where nitrate was scarce, GBT was primarily catabolized via the demethylation to glycine. Resulting metabolites were used to build protein biomass, and remineralized ammonia was re-assimilated into cells. Gene expression data from this region show that bacteria, especially SAR11, are the dominant organisms expressing the demethylation genes. Where nitrate concentrations were higher, more GBT was used for choline synthesis. Our data highlight undiscussed metabolic pathways and potential routes of microbial metabolite exchange.
2021-12-01 | ST002008 | MetabolomicsWorkbench
Project description:BACKGROUND: With the aim of remaining viable, bacteria must deal with changes in environmental conditions, including increases in external osmolarity. While studies concerning bacterial response to this stress condition have focused on soil, marine and enteric species, this report is about Caulobacter crescentus, a species inhabiting freshwater oligotrophic habitats. RESULTS: A genomic analysis reported in this study shows that most of the classical genes known to be involved in intracellular solute accumulation under osmotic adaptation are missing in C. crescentus. Consistent with this observation, growth assays revealed a restricted capability of the bacterium to propagate under hyperosmotic stress, and addition of the compatible solute glycine betaine did not improve bacterial resistance. A combination of transcriptomic and proteomic analyses indicated quite similar changes triggered by the presence of either salt or sucrose, including down-regulation of many housekeeping processes and up-regulation of functions related to environmental adaptation. Furthermore, a GC-MS analysis revealed some metabolites at slightly increased levels in stressed cells, but none of them corresponding to well-established compatible solutes. CONCLUSION: Despite a clear response to hyperosmotic stress, it seems that the restricted capability of C. crescentus to tolerate this unfavorable condition is probably a consequence of the inability to accumulate intracellular solutes. This finding is consistent with the ecology of the bacterium, which inhabits aquatic environments with low nutrient concentration. Three experimental procedures, each of them performed in three replicates. A total of nine independent biological samples were used
2015-04-21 | E-GEOD-49654 | biostudies-arrayexpress
Project description:Listeria monocytogenes SigB and PrfA are pleiotropic regulators of stress response and virulence gene expression, which have been shown to co-regulate genes in L. monocytogenes. We performed whole genome transcriptional profiling in the presence of PrfA* and active SigB, to identify the overlaps between the PrfA virulence regulon and the SigB stress response regulon. In L. monocytogenes, the PrfA* allele contributes to the activation of virulence genes to a level comparable to that of intracellular growing L. monocytogenes. Our results showed that the core PrfA regulon consists of 12 genes previously described as PrfA regulated. Furthermore, we found that the role of SigB during virulence gene regulation changes, dependent on the presence or absence of PrfA*. In the absence of PrfA*, SigB activated the transcription of virulence genes such as inlA and inlB. In the presence of PrfA*, SigB negatively influenced the transcription of genes in the PrfA core regulon. The observed effect of SigB on the transcript level of PrfA regulated genes was shown to reduce the cytotoxic effect of the PrfA* allele in HepG-2 cells. Our results indicate that the SigB-PrfA regulatory network is important for the adjustment of virulence gene transcription to ensure L. monocytogenes success as an intracellular pathogen. Keywords: comparison of gene expression of regulatory mutants
2008-10-01 | GSE11347 | GEO