Project description:System-wide metabolic homeostasis is crucial for maintaining physiological functions of living organisms. Stable-isotope tracing metabolomics allows to unravel metabolic activity quantitatively by measuring the isotopically labeled metabolites, but has been largely restricted by coverage. Yet, delineating system-wide metabolic homeostasis at the whole-organism level remains non-trivial. Here, we develop a global isotope tracing metabolomics technology to measure labeled metabolites with a metabolome-wide coverage. Using Drosophila as an aging model organism, we probe the in vivo tracing kinetics with quantitative information on labeling patterns, extents and rates on a metabolome-wide scale. We curate a system-wide metabolic network to characterize metabolic homeostasis and disclose a system-wide loss of metabolic coordinations that impacts both intra- and inter-tissue metabolic homeostasis significantly during Drosophila aging. Importantly, we reveal an unappreciated metabolic diversion from glycolysis to serine metabolism and purine metabolism as Drosophila aging. The developed technology facilitates a system-level understanding of metabolic regulation in living organisms.
Project description:The study investigated the effect of different carbon sources on E. coli global gene expression. We grew MG1655 cells aerobically in MOPS minimal medium with either glucose, glycerol, succinate, L-alanine, acetate, or L-proline as the carbon supply. Samples were taken from each culture at mid log phase and were RNA-stabilized using Qiagen RNAProtect Bacterial Reagent (Qiagen). Total RNA was then isolated using MasterPure kits (Epicentre Technologies). Purified RNA was reverse-transcribed to cDNA, labeled and hybridized to Affymetrix GeneChipÒ E. coli Antisense Genome Arrays as recommended in the technical manual (www.affymetrix.com). Keywords: parallel sample
Project description:Colorectal cancer (CRC) is the third most commonly diagnosed cancer in American men and women with ≥130,000 new cases each year. Several dietary patterns have been associated with CRC risk but underlying mechanisms are not fully understood. Researchers thus propose to integrate dietary patterns and metabolomics data to comprehensively investigate biological pathways linking dietary patterns and CRC risk.
Project description:This dataset is part of a study aimed at developing algorithms for the quantification of stable isotope content in microorganisms after labeling them with stable isotope-labeled substrates. In this dataset Escherichia coli cultures were labeled with different percentages (1% or 10%) of either single-carbon 13C glucose (13C2) or fully-labeled 13C glucose (13C1-6). Labeled cells were subsequently mixed with unlabeled E. coli cells in fixed ratios (50%, 90%, 95%, 99%). Cultures of E. coli were grown in M9 minimal medium in which a percentage of the glucose was replaced with 13C2 or 13C1-6 glucose for >10 generations to achieve close to complete labeling of cells. Triplicate cultures were grown for each percentage. Please note that the unlabeled glucose that was used of course had a natural content of 13C of around 1.1%, thus the 0% added label samples have an actual 13C content of 1.1% and all added label is on top of this value. We included a tab delimited table with this submission providing details on all raw files.
Project description:By fermenting dietary fiber, the gut microbiota supplies carbon to host epithelial cells in the form of short-chain fatty acids and other metabolic byproducts. To track the transfer of carbon from fiber to host tissues via the microbiota and more clearly define the molecules mediating this transfer, we conducted stable isotope tracing in mice with U-13C-labeled inulin followed by untargeted metabolomics by LC-MS. Additionally, we applied this labeling approach to mice with chemically induced colitis to examine how inflammation impacts carbon transfer from the microbiota to host tissues, which may aid in understanding the development of inflammatory bowel diseases.
Project description:The interplay between pathogens and hosts has been studied for decades using targeted approaches such as the analysis of mutants and host immunological responses. Although much has been learned from such studies, they focus on individual pathways and fail to reveal the global effects of infection on the host. To alleviate this issue, high-throughput methods such as transcriptomics and proteomics have been used to study host-pathogen interactions. Recently, metabolomics was established as a new method to study changes in the biochemical composition of host tissues. We report a metabolomics study of Salmonella enterica serovar Typhimurium infection. We used Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Direct Infusion to reveal that dozens of host metabolic pathways are affected by Salmonella in a murine infection model. In particular, multiple host hormone pathways are disrupted. Our results identify unappreciated effects of infection on host metabolism and shed light on mechanisms used by Salmonella to cause disease, and by the host to counter infection. Female C57BL/6 mice were infected with Salmonella enterica serovar Typhimurium SL1344 cells by oral gavage. Feces and livers were collected and metabolites extracted using acetonitrile. For experiments with feces, samples were collected from 4 mice before and after infection. For liver experiments, 11 uninfected and 11 infected mice were used. Samples were combined into 3 groups of 3-4 mice each, resulting in the analysis of 3 group samples of uninfected and 3 of infected mice. Extracts were infused into a 12-T Apex-Qe hybrid quadrupole-FT-ICR mass spectrometer equipped with an Apollo II electrospray ionization source, a quadrupole mass filter and a hexapole collision cell. Raw mass spectrometry data were processed as described elsewhere (Han et al. 2008. Metabolomics. 4:128-140 [PMID 19081807]). To identify differences in metabolite composition between uninfected and infected samples, we filtered the list of masses for metabolites which were present on one set of samples but not the other. Additionally, we calculated the ratios between averaged intensities of metabolites from uninfected and infected mice. To assign possible metabolite identities, monoisotopic neutral masses of interest were queried against MassTrix (http://masstrix.org). Masses were searched against the Mus musculus database within a mass error of 3 ppm. Data were analyzed by unpaired t tests with 95% confidence intervals.
Project description:The severe harm of depression to human life has attracted great attention to neurologists, but its pathogenesis is extremely complicated and has not yet been fully elaborated. Here, we provided a new strategy for revealing the specific pathways of abnormal brain glucose catabolism in depression, which from the supply of energy substrates and the evaluation of mitochondrial structure and function. By using stable isotope-resolved metabolomics technique, we discovered the tricarboxylic acid cycle (TCA cycle) is blocked and the gluconeogenesis is abnormally activated in chronic unpredictable mild stress (CUMS) rats. In addition, our results showed an interesting phenomenon that the brain attempted to activate all possible metabolic enzymes in energy-producing pathways, but CUMS rats still exhibited a low TCA cycle activity due to impaired mitochondria. Depression caused mitochondrial structure and function impaired, and then led to abnormal brain glucose catabolism. The combination of the stable isotope-resolved metabolomics and mitochondrial structure and function analysis can accurately clarify the mechanism of depression. The mitochondrial pyruvate carrier and acetyl-CoA maybe the key targets for depression treatment. The strategy provides a unique insight for exploring the mechanism of depression, the discovery of new targets, and the development of ideal novel antidepressants.
Project description:The interplay between pathogens and hosts has been studied for decades using targeted approaches such as the analysis of mutants and host immunological responses. Although much has been learned from such studies, they focus on individual pathways and fail to reveal the global effects of infection on the host. To alleviate this issue, high-throughput methods such as transcriptomics and proteomics have been used to study host-pathogen interactions. Recently, metabolomics was established as a new method to study changes in the biochemical composition of host tissues. We report a metabolomics study of Salmonella enterica serovar Typhimurium infection. We used Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Direct Infusion to reveal that dozens of host metabolic pathways are affected by Salmonella in a murine infection model. In particular, multiple host hormone pathways are disrupted. Our results identify unappreciated effects of infection on host metabolism and shed light on mechanisms used by Salmonella to cause disease, and by the host to counter infection.