Project description:Interventions: Gold Standard:pathological diagnosis ;Index test:Volatile organic compounds detected by gas chromatography-mass spectrometer and gas chromatography-ion migration spectrometry
Primary outcome(s): Volatile organic compounds;sensitivity;specificity
Study Design: Diagnostic test for accuracy
Project description:For metabolic profiling of mouse CD4+ T cells, stable isotope labeling (SIL) experiments were performed with in vitro-activated T cells using gas chromatography (GC) coupled to mass spectrometry (MS).
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 aim of this study is to determine the active components of HTG and to reveal its possible targets and mechanisms of action for the treatment of AR. Through mass spectrometry, six components, including ononin, paeoniflorin, psoralenoside, isoliquiritin apioside, glycyrrhizic acid and arctiin were identified. Further studies employing SymMap database and TMNP algorithm showed that IFN-γ, which has been demonstrated to be a molecular link between immunity and neural circuits, is a key target involved in the HTG treatment of AR. The enrichment of several immune and virus-related signaling pathways together indicated the neuroimmuno-modulatory potential of HTG.
Project description:Vacuoles and lysosomes are single-membrane-bound organelles involved in diverse functions such as intracellular digestion and storage or secretion of metabolites. To understand their origin, evolution and fundamental features, the identification of proteins comprising these compartments in missing links would be invaluable. So, we isolated the vacuoles from Cyanidioschyzon merolae, which is considered to be one of the most primitive photosynthetic eukaryotes, and identified 46 proteins by matrix-assisted laser desorption/ionization time of flight-mass spectrometry. Keywords: peptide mass fingerprinting, MALDI-TOF