Project description:Comparisons of overexpression of PreA (in wt or preAB mutant Salmonella) to Salmonella lacking preA or preAB in late log phase growth in LB preA was externally supplied to wt or preAB mutant Salmonella typhimurium on a pBAD18 plasmid, which was then induced by 10mM arabinose and grown to late log phase (OD0.74). Transcription profiles were compared with those obtained from preA or preAB mutant Salmonella harboring pBAD18 only as vector control.
Project description:S. typhimurium 14028 wt, hfq and smpB were harvested from log phase LB (LBlog); (2), stationary phase LB (LBstat); (3) 4h MgM medium pH 5.0 after resuspension of LB stat culture (MgMshock); and (4) log phase MgM medium pH5.0 after 100fold dilution of an LB stat culture (MgMDil). Total RNA was extracted, cDNA labeled and hybridized to a non-redundant Salmonella whole genome PCR product ORF array.
Project description:Two carbon starvation (cst) genes, cstA and yjiY, in Salmonella are predicted to mediate peptide utilization under nutrient stress. However, the mechanistic details of their function and their importance in the context of Salmonella pathogenesis is not addressed. In this study, the transcriptomes of cst gene knockouts were compared to that of wild type to check the global impact of cst genes on Salmonella metabolism as well as pathogenesis. Microarray was done for duplicate samples for each strain in late log phase of growth in LB, which is also marked by the expression of many virulence associated genes.
Project description:In this study, we have defined the NsrR regulon in Salmonella enterica sv. Typhimurium 14028s using a transcriptional microarray. Wild-type and nsrR mutant S. Typhimurium were grown aerobically to early log-phase (OD600~0.5) at 37C in LB medium. Total RNA was isolated from three independent cultures of both strains and interrogated on a PCR product array representing almost all ORFs.
Project description:S. typhimurium 14028 wt, hfq and smpB were harvested from log phase LB (LBlog); (2), stationary phase LB (LBstat); (3) 4h MgM medium pH 5.0 after resuspension of LB stat culture (MgMshock); and (4) log phase MgM medium pH5.0 after 100fold dilution of an LB stat culture (MgMDil). Total RNA was extracted, cDNA labeled and hybridized to a non-redundant Salmonella whole genome PCR product ORF array. S. typhimurium 14028 cells were harvested, on three separate days, (1), after growth at 30°C to log phase in LB (LBlog); (2), after growth at 30°C to stationary phase in LB (LBstat); (3) after transfer of a stationary phase culture grown in LB into magnesium-deficient MgM medium [100 mM Tris-Cl, 5 mM KCl, 7.5 mM (NH4)2SO4, 0.5 mM K2SO4, 1 mM KH2PO4, 0.2% glycerol, 0.1% Casamino acids, 8uM MgCl2] pH 5.0 and growth for four more hours at 30°C (MgMshock); (4) after 100fold dilution of a stationary phase culture grown in LB into magnesium-deficient MgM medium pH5.0 and growth at 30°C to log phase (MgMDil). This procedure was performed on (A), wild type [WT] cells; (B), cells of an hfq- (STM4361) knockout mutant; and (C), cells of an smpB- (STM2688) knockout mutant, resulting in 36 samples total. Total RNA was extracted, cDNA labeled with Cy5-dCTP and hybridized versus Cy3-labeled 14028 gDNA to a non-redundant Salmonella whole genome PCR product ORF array.
Project description:Two carbon starvation (cst) genes, cstA and yjiY, in Salmonella are predicted to mediate peptide utilization under nutrient stress. However, the mechanistic details of their function and their importance in the context of Salmonella pathogenesis is not addressed. In this study, the transcriptomes of cst gene knockouts were compared to that of wild type to check the global impact of cst genes on Salmonella metabolism as well as pathogenesis. Microarray was done for duplicate samples for each strain in late log phase of growth in LB, which is also marked by the expression of many virulence associated genes. Organism : Salmonella typhimurium , Agilent Custom Salmonella Typhimurium Gene Expression 8x15k Array (AMADID: 046639) designed by Genotypic Technology Private Limited.
Project description:Transcriptional profiling of Salmonella Typhimurium SL1344 parental starin and isogenic M-bM-^HM-^FrelA, M-bM-^HM-^FspoT ppGpp null strain grown in LB medium with RNA samples talken at AD600=1.0 (mid log, ML), 2.3 (early stationary phase, ESP), 3.0 (mid stationary phase MSP) and 3.6 (Late stationary phase (LSP) Each array used labelled cDNA against a common genomic DNA reference. Triplicate biologically independent RNA samples were arrayed for each of the 2 strains at each of the 4 growth phases
Project description:Transcriptional profiles of a chlorhexidine tolerant Salmonella Typhimurium were compared to its, chlorhexidine sensitive, isogenic progenitor isolate. RNA was extracted from mid-log phase cells from both isolates, without chlorhexidine exposure and following exposure to 1 µg/ ml of chlorhexidine for 30 minutes. Transcriptional profiles of the tolerant isolate were compared to the sensitive isolate, with and without chlorhexidine exposure.
Project description:StpA is a paralogue of the nucleoid associated protein H-NS that is conserved in a range of enteric bacteria and had no known function in Salmonella enterica serovar Typhimurium. Here, we show that 5% of the Salmonella genome is regulated by StpA, which contrasts with the situation in Escherichia coli where deletion of stpA only had minor effects on gene expression. The StpA-dependent genes of S. Typhimurium are a specific subset of the H-NS regulon that are predominantly under the positive control of sigma38 (RpoS), CRP-cAMP and PhoP. The regulatory role of StpA varied at different growth phases; StpA only controlled sigma38 levels at mid-exponential phase when it prevented inappropriate activation of sigma38 during rapid bacterial growth. In contrast, StpA only activated the CRP-cAMP regulon during late exponential phase. The effect of stpA deletion on S. Typhimurium gene expression during growth in LB was analysed at 4 different time points (early-log, mid-log, late-log, and stationary phase) where the gene expression profile of the stpA-deletion strain was compared to that of the parental strain. Between two and three biological replicates were performed for each strain and time point. For this study, we used Salmonella genomic DNA as the comparator which also acted as the control for spot quality.