Salmonella enterica subsp. enterica serovar Typhimurium
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PROVIDER: PRJNA137835 | ENA |
REPOSITORIES: ENA
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Project description:The antimicrobial activity of organic acids in combination with non-chemical treatments was evaluated for inactivation of Salmonella Typhimurium. It was observed that the effectiveness of the multiple hurdle treatments were temperature and pH dependent and corresponded to the degree of organic acid lipophilicity. This led to the hypothesis that the loss in viability was due to cell membrane disruption. Evaluation of osmotic response, potassium ion leakage, and transmission electron micrographs confirmed effects on the cell membrane following treatment. Interestingly, all treatments, even those with no affect on viability, such as with sodium acetate, resulted in measurable cellular stress. Microarray experiments explored the specific response of S. Typhimurium to sodium acetate and sodium propionate, the most similar treatments in terms of pKa and ionic strength, and found little difference in the changes in gene expression following either treatment, despite their very different effects on viability. Taken together, the results reported support our hypothesis that following treatment with heated, acidified, organic acid salts, the loss of S. Typhimurium viability is at least in part due to membrane damage and the more lipophilic the organic acid the more effective the treatment. Overall, the data presented here indicate that a combined thermal, acidified sodium propionate treatment can provide a simple, yet effective antimicrobial treatment to combat Salmonella.
2011-03-20 | GSE27922 | GEO
Project description:Stress response of Salmonella Typhimurium to acidified nitrite
| PRJNA246027 | ENA
Project description:The antimicrobial action of the curing agent NaNO2, which is added as a preservative to raw meat products, depends on its conversion to nitric oxide and other reactive nitrogen species under acidic conditions. In this study, we applied RNA-sequencing to analyze the acidified NaNO2 shock and adaptive response of Salmonella Typhimurium, a frequent contaminant in raw meat. Upon a 10 minute exposure to 150 mg/l NaNO2 in LB pH 5.5 acidified with lactic acid, genes involved in nitrosative stress protection together with several other stress related genes were induced. To the contrary, genes involved in translation, transcription, replication and motility were down-regulated. Induction of stress tolerance and reduction of cell proliferation obviously promote survival under harsh acidified NaNO2 stress. The subsequent adaptive response was characterized by up-regulation of NsrR-regulated genes and iron-uptake systems and down-regulation of genes involved in anaerobic respiratory pathways. Strikingly, amino acid decarboxylase systems, which contribute to acid tolerance, displayed increased transcript levels in response to acidified NaNO2. The induction of systems known to be involved in acid resistance indicates a nitrite mediated increase of acid stress. Transcriptome of Salmonella Typhimurium 14028, treated at OD600 = 0.80-0.85 with 150 mg/l NaNO2 (acidified by lactic acid in the growth medium) for 10 min (shock response) or until an OD600 = 1.45-1.55 is reached (1.5 - 2.0 h, adaptation response), was compared to respective control cultures without NaNO2. Amplified cDNA libraries for sequencing on the SOLiD 5500xl system were prepared from one culture per condition.
2014-08-25 | E-GEOD-57238 | biostudies-arrayexpress
Project description:The antimicrobial action of the curing agent NaNO2, which is added as a preservative to raw meat products, depends on its conversion to nitric oxide and other reactive nitrogen species under acidic conditions. In this study, we applied RNA-sequencing to analyze the acidified NaNO2 shock and adaptive response of Salmonella Typhimurium, a frequent contaminant in raw meat. Upon a 10 minute exposure to 150 mg/l NaNO2 in LB pH 5.5 acidified with lactic acid, genes involved in nitrosative stress protection together with several other stress related genes were induced. To the contrary, genes involved in translation, transcription, replication and motility were down-regulated. Induction of stress tolerance and reduction of cell proliferation obviously promote survival under harsh acidified NaNO2 stress. The subsequent adaptive response was characterized by up-regulation of NsrR-regulated genes and iron-uptake systems and down-regulation of genes involved in anaerobic respiratory pathways. Strikingly, amino acid decarboxylase systems, which contribute to acid tolerance, displayed increased transcript levels in response to acidified NaNO2. The induction of systems known to be involved in acid resistance indicates a nitrite mediated increase of acid stress.
2014-08-25 | GSE57238 | GEO
Project description:FabR ChIP-chip on Salmonella enterica subsp. enterica serovar Typhimurium SL1344 using anti-Myc antibody against strain with chromosomally 9Myc-tagged FabR (IP samples) and wildtype strain (mock IP samples)
2014-12-31 | GSE52877 | GEO
Project description:Salmonella enterica serovar Typhimurium (S. Typhimurium) infection triggers an inflammatory response that changes the concentration of luminal metabolites in the gut, resulting in a distinct environment from a healthy one. We recently demonstrated that S. Typhimurium possesses the ability to form biofilms within the host environment and responds to nitrate as a signaling molecule, enabling it to modulate the transition between sessile and planktonic states. To investigate whether S. Typhimurium utilizes additional metabolites to regulate its behavior, our study delved into the impact of inflammatory metabolites on biofilm formation. Employing a transcriptomic approach we unveiled that lactate enhances the transcription of flagella and invasion genes, highlighting the active role of lactate in modulating the transition of S. Typhimurium from biofilm to motile states. All these findings propose that, as occurring with nitrate, lactate is an inflammatory metabolite being used by S. Typhimurium to support virulence.
2024-10-23 | GSE255285 | GEO
Project description:Cell to cell communication in bacteria to regulate various cellular processes with respect to their population density is termed quorum sensing and is achieved using signaling molecules called autoinducers. LuxS, which is involved in the synthesis of the autoinducer molecule-2 (AI-2), is conserved in several Gram-positive and Gram-negative bacteria including the enteric pathogen Salmonella Typhimurium. Genes that are regulated by luxS in S. Typhimurium were identified using microarrays and RNA samples from wild type S. Typhimurium and its isogenic luxS mutant, in two growth conditions (presence and absence of glucose), and at two different time points (mid-log and early-stationary phases). Minimal differential gene expression was observed in the presence of glucose. In the absence of both luxS and glucose, a total of 1560 genes were differentially expressed and 1361 genes were identified as luxS/AI-2-regulated at the mid-log phase and 199 genes at the early-stationary phase. Quantitative real-time PCR was performed on selected genes to validate the microarray results. These results suggest that although the expression of the luxS gene in S. Typhimurium is independent of the growth condition, its role in the production of AI-2 depends on the growth condition. It was found that luxS/AI-2 plays a vital role in a variety of processes such as metabolism, virulence gene expression, motility, transcription and translation. Keywords: Salmonella Typhimurium, quorum sensing, luxS mutant, autoinducer-2
2009-10-22 | GSE7558 | GEO
Project description:Investigation of whole genome gene expression level changes in a Salmonella enterica serovar Typhimurium UK1 delta-iacP mutant, compared to the wild-type strain. IacP is resoponsible for the secretion of virulence effector proteins via the type III secretion system, thereby contributing the virulence of S. Typhimurium. The mutants analyzed in this study are further described in Kim et al. 2011. Role of Salmonella Pathogenicity Island 1 Protein IacP in Salmonella enterica Serovar Typhimurium Pathogenesis. Infection and Immunity 79(4):1440-1450 (PMID 21263021).
2012-04-30 | GSE34663 | GEO
Project description:To investigate the effects of MccY on Salmonella Typhimurium, Ton system genes mutants were constructed and RNA-seq analysis were performed.
2022-09-29 | GSE214184 | GEO
Project description:Bacterial transcription networks typically consist of hundreds of transcription factors and thousands of promoters. However, current attempts to map bacterial promoters have failed to report the true complexity of bacterial transcription. The differential RNA-seq (dRNA-seq) approaches only identified a subset of promoters because they involved few growth conditions. Here, we present a simplified approach for global promoter identification in bacteria, based upon the analysis of RNA-seq data from multiple environmental conditions. RNA was extracted from Salmonella enterica serovar Typhimurium (S. Typhimurium) grown in 22 different environmental conditions, which were devised to reflect the pathogenic lifestyle of S. Typhimurium. Individual RNA samples were combined into two pools for sequencing. In just two runs of strand-specific RNA-seq and dRNA-seq of the pooled sample we identified 3701 promoters (Pool sample). In further experiments, we found that individual in vitro conditions stimulate the expression of about 60% of the S. Typhimurium genome, whereas the suite of 22 conditions induced expression of 87% of S. Typhimurium genes. We discovered environmental conditions that induce many genes within Salmonella pathogenicity islands and identified 78 new sRNAs. In S. Typhimurium there is now experimental evidence for 280 sRNAs, and we classified them in terms of location and Hfq-binding.
2013-12-18 | GSE49829 | GEO