Salmonella enterica subsp. enterica serovar Typhimurium
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PROVIDER: PRJNA120985 | ENA |
REPOSITORIES: ENA
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Project description:Glucose-lysine based Maillard reaction products (MRPs) are introduced to the human body via food ingestion or are synthesized in vivo. Depending on reaction conditions, they represent a mixture of compounds with diverse chemical structures and physiological properties. MRPs may also be a potential nutrient source for Salmonella, a major foodborne gastrointestinal pathogen. This study was designed to determine the growth and transcriptional responses of S. Typhimurium LT2 to MRPs generated at low water activity to simulate the reaction occurring during food processing and storage. Maillard reactions between N-α-acetyl-lysine and glucose were varied in time (4, 23, and 143 h) to generate sub-samples with prevailing Amadori compound, advanced glycation end products (AGEs), or melanoidines respectively. The addition of MRP up to 5 mg mL-1 to defined media with 0.4% glucose had no effect on S. Typhimurium LT2 growth. In media, where the MRP sub-samples (4 and 23 h) served as the only carbon source, MRP assimilation by S. Typhimurium LT2 was observed as secondary logarithmic growth phases (0.063 h-1 and 0.072 h-1) after the growth on glucose available in the MRP reaction mixtures (0.479 h-1). The MRPs sub-sample with the highest concentration of melanoidines (143 h) also supported S. Typhimurium LT2 growth (0.368 h-1). Of the three MRPs sub-samples, the Amadori compound was the preferred carbon source for S. Typhimurium LT2 as evidenced by its almost complete disappearance (98%). Decreases in AGEs (37%) and melanoidines (15%), when incubated with S. Typhimurium LT2, also occurred. Transcription profiles of the cells grown on the MRPs fractions revealed predominant up-regulation of genes associated with the functional groups of energy metabolism, fatty and phospholipid metabolism, cellular process, and regulatory functions, and general down-regulation of the genes in the groups of amino acid biosynthesis, protein synthesis and transcription, transport and binding proteins, and DNA metabolism. The carbon flow in tricarboxylic acid (TCA) cycle partitioned by the glyoxylate cycle appeared to play an essential role in the assimilation of glucose-lysine-derived MRPs. The high expression level of numerous genes encoding hypothetical proteins or proteins with unknown function suggested the presence of genes whose role in glucose-lysine MRPs catabolism in Salmonella remains to be determined.
2009-12-25 | GSE18950 | GEO
Project description:Glucose-lysine based Maillard reaction products (MRPs) are introduced to the human body via food ingestion or are synthesized in vivo. Depending on reaction conditions, they represent a mixture of compounds with diverse chemical structures and physiological properties. MRPs may also be a potential nutrient source for Salmonella, a major foodborne gastrointestinal pathogen. This study was designed to determine the growth and transcriptional responses of S. Typhimurium LT2 to MRPs generated at low water activity to simulate the reaction occurring during food processing and storage. Maillard reactions between N-α-acetyl-lysine and glucose were varied in time (4, 23, and 143 h) to generate sub-samples with prevailing Amadori compound, advanced glycation end products (AGEs), or melanoidines respectively. The addition of MRP up to 5 mg mL-1 to defined media with 0.4% glucose had no effect on S. Typhimurium LT2 growth. In media, where the MRP sub-samples (4 and 23 h) served as the only carbon source, MRP assimilation by S. Typhimurium LT2 was observed as secondary logarithmic growth phases (0.063 h-1 and 0.072 h-1) after the growth on glucose available in the MRP reaction mixtures (0.479 h-1). The MRPs sub-sample with the highest concentration of melanoidines (143 h) also supported S. Typhimurium LT2 growth (0.368 h-1). Of the three MRPs sub-samples, the Amadori compound was the preferred carbon source for S. Typhimurium LT2 as evidenced by its almost complete disappearance (98%). Decreases in AGEs (37%) and melanoidines (15%), when incubated with S. Typhimurium LT2, also occurred. Transcription profiles of the cells grown on the MRPs fractions revealed predominant up-regulation of genes associated with the functional groups of energy metabolism, fatty and phospholipid metabolism, cellular process, and regulatory functions, and general down-regulation of the genes in the groups of amino acid biosynthesis, protein synthesis and transcription, transport and binding proteins, and DNA metabolism. The carbon flow in tricarboxylic acid (TCA) cycle partitioned by the glyoxylate cycle appeared to play an essential role in the assimilation of glucose-lysine-derived MRPs. The high expression level of numerous genes encoding hypothetical proteins or proteins with unknown function suggested the presence of genes whose role in glucose-lysine MRPs catabolism in Salmonella remains to be determined. This study was designed to determine the growth and transcriptional responses of S. Typhimurium LT2 to MRPs generated at low water activity to simulate the reaction occurring during food processing and storage. Maillard reactions between N-α-acetyl-lysine and glucose were varied in time (4, 23, and 143 h) to generate sub-samples with prevailing Amadori compound, advanced glycation end products (AGEs), or melanoidines respectively. Total bacterial RNA was isolated as previously described and the RNA samples were then converted to fluorescently-labeled cDNA and hybridized to S. Typhimurium microarrays version 5 (NIAID's Pathogen Functional Genomics Resource Center). Real-time PCR and physiological experiments were performed to validate the microarray data. In all supplementary files channel A = Cy3, channel B = Cy5.
2010-05-16 | E-GEOD-18950 | biostudies-arrayexpress
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:Transcriptional profiling of three sequenced S. enterica strains: S. Typhimurium LT2, S. Typhi CT18, and S. Typhi Ty2 in PhoP-inducing and non-inducing conditions in vitro, and compared these results to profiles of phoP-/Q- mutants derived from S. Typhimurium LT2 and S. Typhi Ty2.
2009-08-19 | GSE17670 | GEO
Project description:Salmonella enterica serovar Typhimurium (S. Typhimurium) definitive phage type 104 (DT104) has caused significant morbidity and mortality in humans and animals for almost three decades. We have completed the full DNA sequence of one DT104 strain, NCTC13348 and show that the main differences between the genome of this isolate and the previously sequenced S. Typhimurium LT2 lie in integrated prophage elements and the Salmonella Genomic Island 1 encoding antibiotic resistance genes. Thirteen isolates of S. Typhimurium DT104 with different pulsed field gel electrophoresis (PFGE) profiles were analyzed by multi locus sequence typing (MLST), plasmid profiling, hybridization to a Pan-Salmonella DNA microarray and prophage-based multiplex PCR. All the isolates belonged to a single MLST type ST19. Microarray data demonstrated that the 13 DT104 isolates were remarkably conserved in gene content. The PFGE band-size differences in these isolates could be explained to a great extent by changes in prophage and plasmid content. Thus, here the nature of variation in different S. Typhimurium DT104 isolates is further defined at the genome level illustrating how this phage type is evolving over time.
2008-09-05 | E-MTAB-20 | biostudies-arrayexpress
Project description:Obacunone is a limonoids present in Citrus species. We previously reported that obacunone was inhibitory to the cell-cell signaling in Vibrio harveyi and Escherichia coli O157:H7. In the present work we evaluated the effect of obacunone on the food borne pathogen Salmonella Typhimurium LT2 using cDNA microarray. The results demonstrate that obacunone exerts an antivirulence effect on S. Typhimurium LT2 by repressing SPI1 and SPI2. Furthermore, the effect of obacunone seems to be dependent upon EnvZ.
2012-08-21 | GSE37234 | GEO
Project description:Salmonella Typhimurium LT2: Control versus naringenin
| PRJNA127063 | ENA
Project description:Investigation of whole genome gene expression level changes in a Salmonella enterica serovar Typhimurium 14028 delta GidA mutant The mutant described in this study is further analyzed in Shippy, D. C., N. M. Eakley, P. N. Bochsler, and A. A. Fadl. 2011. Biological and virulence characteristics of Salmonella enterica serovar Typhimurium following deletion of glucose-inhibited division (gidA) gene. Microb Pathog.
2011-07-20 | GSE30787 | GEO
Project description:RNA-seq analysis of Salmonella enterica Typhimurium LT2
| PRJNA194147 | ENA
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