Polar accumulation of pyoverdin and exit from stationary phase
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PROVIDER: S-EPMC10873284 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:IntroductionAccurately identifying and quantifying polar metabolites using untargeted metabolomics has proven challenging in comparison to mid to non-polar metabolites. Hydrophilic interaction chromatography and gas chromatography-mass spectrometry are predominantly used to target polar metabolites.ObjectivesThis study aims to demonstrate a simple one-step extraction combined with liquid chromatography-mass spectrometry (LC-MS) that reliably retains polar metabolites.MethodsThe method involves a MilliQ + 10% trichloroacetic acid extraction from 6 healthy individuals serum, combined with porous graphitic carbon liquid chromatography-mass spectrometry (LC-MS). The coefficient of variation (CV) assessed retention reliability of polar metabolites with logP as low as - 9. QreSS (Quantification, Retention, and System Suitability) internal standards determined the method's consistency and recovery efficiency.ResultsThe method demonstrated reliable retention (CV < 0.30) of polar metabolites within a logP range of - 9.1 to 5.6. QreSS internal standards confirmed consistent performance (CV < 0.16) and effective recovery (70-130%) of polar to mid-polar metabolites. Quality control dilution series demonstrated that ~ 80% of annotated metabolites could be accurately quantified (Pearson's correlation coefficient > 0.80) within their concentration range. Repeatability was demonstrated through clustering of repeated extractions from a single sample.ConclusionThis LC-MS method is better suited to covering the polar segment of the metabolome than current methods, offering a reliable and efficient approach for accurate quantification of polar metabolites in untargeted metabolomics.
| S-EPMC11252196 | biostudies-literature
Project description:Observations of bacteria at the single-cell level have revealed many instances of phenotypic heterogeneity within otherwise clonal populations, but the selective causes, molecular bases, and broader ecological relevance remain poorly understood. In an earlier experiment in which the bacterium Pseudomonas fluorescens SBW25 was propagated under a selective regime that mimicked the host immune response, a genotype evolved that stochastically switched between capsulation states. The genetic cause was a mutation in carB that decreased the pyrimidine pool (and growth rate), lowering the activation threshold of a preexisting but hitherto unrecognized phenotypic switch. Genetic components surrounding bifurcation of UTP flux toward DNA/RNA or UDP-glucose (a precursor of colanic acid forming the capsules) were implicated as key components. Extending these molecular analyses-and based on a combination of genetics, transcriptomics, biochemistry, and mathematical modeling-we show that pyrimidine limitation triggers an increase in ribosome biosynthesis and that switching is caused by competition between ribosomes and CsrA/RsmA proteins for the mRNA transcript of a positively autoregulated activator of colanic acid biosynthesis. We additionally show that in the ancestral bacterium the switch is part of a program that determines stochastic entry into a semiquiescent capsulated state, ensures that such cells are provisioned with excess ribosomes, and enables provisioned cells to exit rapidly from stationary phase under permissive conditions.
| S-EPMC6501884 | biostudies-literature
Project description:Transcriptional profiling of A. oleivorans DR1 cells comparing wild type stationary phase cells with aqsR mutant stationary phase cells.
2013-02-16 | GSE44347 | GEO
Project description:Nine day glucose starvation stationary phase culture, exit and entry from quiescence
2005-04-15 | E-UMCU-12 | biostudies-arrayexpress
Project description:Transcriptional profiling of A. oleivorans DR1 cells comparing wild type stationary phase cells with aqsR mutant stationary phase cells. To identify genes regulated QS system in A. oleivorans DR1, the cells were grown to stationary phase (OD600 >0=2.0).
2013-02-16 | E-GEOD-44347 | biostudies-arrayexpress
Project description:Paramecium cells in stationary phase were treated for deciliation and total mRNA extracted at two time points (45 and 130 minutes) after deciliation. Keywords: Time course analysis of expression during reciliation
2009-11-01 | GSE14631 | GEO
Project description:To determine where Xbp1 binds to chromatin during log phase and stationary phase, we performed ChIP-seq.
2022-08-17 | GSE210933 | GEO
Project description:Background: As carbon sources are exhausted, Saccharomyces cerevisiae cells exhibit reduced metabolic activity and cultures enter stationary phase. We asked whether cells in stationary-phase cultures respond to additional stress at the level of transcript abundance. Results: Microarrays were used to quantify changes in transcript abundance in cells from stationary-phase cultures. In response to oxidative stress, more than 800 mRNAs increased within 1 minute. A significant number of these mRNAs encode proteins involved in stress responses. We tested whether mRNA increases were due to new transcription, rapid poly-adenylation of message (which would not be detected by microarrays), or potential release of mature mRNA sequestered in the cell but insoluble during RNA isolation. Examination of the response to oxidative stress in an RNA polymerase II mutant, rpb1-1 suggested new transcription was not required. Quantitative RT-PCR analysis of a subset of these transcripts further suggested that essentially all isolated transcripts were polyadenylated. In contrast, over 1000 transcripts increased after protease treatment of cell-free lysates from stationary-phase but not exponentially growing cultures. We also determined that oxidative stress and temperature upshift led to the release of different transcripts, suggesting that mRNA release is stress specific. Conclusions: A large number of mRNAs are sequestered in a protease-labile, rapidly releasable form in cells in stationary-phase cultures but not exponentially growing cultures. The differences between mRNAs released by protease treatment and those observed with oxidative stress and temperature upshift, suggest different stresses cause the release of different transcripts. We hypothesize that P-bodies are involved in this sequestration. Keywords: stress response
2005-12-03 | GSE3729 | GEO
Project description:Wild type and ypl230w mutant under stationary phase. Cultures were grown to OD600 of 0.27 (Ypl230w mutants) and 0.4 (congenic wild-type; DBY8778), at which point time zero samples were collected. Samples were further collected at 2 (or 3), 5, 7, 9, and 24 hours. Experimental samples were used to generate Cy5-labeled cDNA probes, whereas mRNA reference pools extracted from cultures of the respective strains grown to early log phase under normal conditions, were used to generate Cy3-labeled cDNA probes. Cy5- and Cy3-labeled probes were hybridized together to microarrays printed with PCR-amplified fragments, representing 6280 of the Saccharomyces cerevisiae ORFs. Keywords: time-course
2003-04-15 | GSE408 | GEO
Project description:The cold shock proteins belong to a family of RNA binding proteins presenting a highly conserved domain, called cold shock domain (CSD). They are involved in various cellular processes, including adaptation to low temperature, nutritional stress, cell growth and stationary phase. Here we investigate the role of CspC in C. crescentus stationary phase and the molecular mechanisms underlying gene regulation by this protein. A global transcriptional profiling experiment comparing cspC and the wild type strain both at exponential and stationary phases was carried out. The results showed that the absence of cspC affected the transcription of 20 genes at exponential phase and 65 genes at stationary phase. Genes encoding enzymes of the glyoxylate cycle were severely downregulated in the mutant at stationary phase. The stationary phase-induced RNA binding protein CspC has an important role in gene expression at this phase. It is required for the expression of the essential gene sciP, the ECF sigma factor sigU, as well as of the genes for the glyoxylate cycle enzymes and for oxidative stress response.
2015-08-24 | GSE61726 | GEO