Methylmalonic acidemia (MMA), propionic acidemia (PA), and cobalamin C deficiency (cblC) share a defect in propionic acid metabolism. In addition, cblC is also involved in the process of homocysteine remethylation. These three diseases produce various phenotypes and complex downstream metabolic effects. In this study we used an untargeted metabolomics approach to investigate the biochemical differences and the possible connections with the pathophysiology of each disease. Untargeted urine metabolomic profiles of 21 patients (7 MMA, 7 PA, 7 cblC) were identified through statistical analysis (p<0.05; log2FC >|1|) and then used for the annotation. Annotated features were associated with different metabolic pathways potentially involved in the diseases development. Comparative statistic showed markedly different metabolomic profiles between MMA, PA and cblC, highlighting characteristic species for each disease. The most affected pathways were related to the metabolism of organic acids (MMA, PA, cblC), amino acids (MMA, PA, cblC), glycine and its conjugates (PA), transsulfuration pathway (cblC), oxidative processes (cblC) and neurosteroid hormones (cblC). The untargeted metabolomics study highlighted the presence of significant differences between the three diseases, pointing to the most relevant contrast of cblC profile compared to MMA and PA. Some new biomarkers are proposed for PA, while novel data regarding the alterations of steroid hormone profiles and biomarkers of oxidative stress were obtained for cblC disease. The elevation of neurosteroids in cblC may indicate a potential connection with the development of ocular and neuronal deterioration.

Total Parenteral Nutrition (TPN), which uses intravenous administration of nutrients, minerals and vitamins, is essential in sustaining premature infants until they transition to enteral feeds. There is limited information on metabolomic differences between infants on TPN and enteral feeds. We performed untargeted global metabolomics on urine samples collected between 23-30 days of life from 314 infants born <29 weeks gestational age from the TOLSURF and PROP cohorts. Principal component analysis across all metabolites showed a separation of infants solely on TPN as compared to infants who had transitioned to enteral feeds, indicating global metabolomic differences between infants based on feeding status. Among 913 metabolites that passed quality control filters, 609 varied in abundance between infants on TPN vs enteral feeds at p<0.05. Of these, 88% were in the direction of higher abundance in the urine of infants on enteral feeds. In a subset of infants with longitudinal analysis, both concurrent and delayed changes in metabolite levels were observed with initiation of enteral feeds. Infants on enteral feeds had higher concentrations of essential amino acids, lipids, and vitamins, which are necessary for growth and development, suggesting a nutritional benefit of an enteral feeding regimen.

Lactobacilli are considered an inexhaustible source of potentially bioactive substances; indeed, several products from their metabolism are known to have immunomodulatory and anti-inflammatory activity. Recently, we demonstrated that cell-free supernatants (CFS) obtained from Lactobacillus (L.) acidophilus, L. plantarum, L. rhamnosus and L. reuteri can impair Candida pathogenic potential in an in vitro model of epithelial vaginal infection. This effect could be ascribed to a direct effect of living lactobacilli on Candida virulence and to the production of metabolites which are able to impair fungal virulence. In the present work, stemming from those data, we deepened our knowledge on the CFS from these 4 lactobacilli by performing a metabolomic analysis to better characterize their composition. By using an untargeted metabolomic approach, we detected consistent differences in the metabolites produced by these four different lactobacilli. Interestingly, L. rhamnosus showed the most peculiar metabolic profile. Specifically, after a hierarchical clustering analysis in positive and negative ionization mode, L. rhamnosus showed a specific area of significant overexpressed metabolites that strongly differed from the same area in other lactobacilli. In this area, inosine was identified among the overexpressed metabolites of L. rhamnosus. This molecule has been described to have antioxidant, anti-inflammatory, anti-infective and neuroprotective properties. The biological significance of its overproduction by L. rhamnosus might be important in its probiotic and/or postbiotic activity.

Background: Atherosclerosis (AS) is a chronic progressive disease caused by lipometabolic disorder. However, the pathological characteristics and mechanism of AS have not been fully clarified. By high fat and cholesterol diet induction, Tibetan minipig could be developed to the AS model animal which had a very similar pathogenesis to human AS. Methods: Here, we built the AS model of Tibetan minipigs and identified the differential abundance metabolites in the development of AS based on untargeted metabolomics. Results: We found that the sphingolipid metabolism and glucose oxidation were enriched in the AS group and the phenylalanine metabolism was reduced in the AS group. Moreover, in the development of AS, gluconolactone was enriched in the late stage of AS whereas biopterin was enriched in the early stage of AS. Conclusion: Gluconolactone and biopterin could be potential biomarkers for indicating the development of AS. Our research provides novel clues for the metabolic mechanism of AS from the perspective of metabolomics.

Untargeted metabolomics is a powerful tool for measuring and understanding complex biological chemistries. However, employment, bioinformatics and downstream analysis of mass spectrometry (MS) data can be daunting for inexperienced users. Numerous open-source and free-to-use data processing and analysis tools exist for various untargeted MS approaches, including liquid chro-matography (LC), but choosing the ‘correct’ pipeline isn’t straight-forward. This tutorial, in con-junction with a user-friendly online guide presents a workflow for connecting these tools to process, analyse and annotate various untargeted MS datasets. The workflow is intended to guide explor-atory analysis in order to inform decision-making regarding costly and time-consuming down-stream targeted MS approaches. We provide practical advice concerning experimental design, organisation of data and downstream analysis, and offer details on sharing and storing valuable MS data for posterity. The workflow is editable and modular, allowing flexibility for updated/ changing methodologies and increased clarity and detail as user participation becomes more common. Hence, the authors welcome contributions and improvements to the workflow via the online repository. We believe that this workflow will streamline and condense complex mass-spectrometry approaches into easier, more manageable, analyses thereby generating opportunities for researchers previously discouraged by inaccessible and overly complicated software.

Salmonella Typhimurium infection in pigs is characterized by an intense inflammatory response in early infection which seems to dysregulate host physiology including the gut microbiota. Both, changes in host physiology and microbiome composition, must entail modifications within the gut environment. This study analyzes the gut metabolome in early infected pigs (48 hours after infection) and non-infected controls by untargeted metabolomics (LC–QTOF MS/MS and GC–TOF MS), supported with microbiome data (16S rRNA abundance and prediction functional analyses). The metabolomic profile in Salmonella-infected pigs differed from healthy controls in 39 of these metabolites, including eight amino acids, four bile acids and carboxylic acids, three carnitines and sugar derivates, eleven fatty acids and six other compounds. Changes in amino acids abundance and the observed decrease of proteolytic bacteria such as Lactobacillus or Bacteroides could favor the niche colonization by Desulfovibrionaceae. In addition, the decrease in short chain fatty acids and tricarboxylic acids cycle was correlated to a decrease in beneficial bacteria in infected pigs. Interestingly, we observed an increase of bile acids concentration and compounds such as succinic acid or pantothenic acid, which may boost the inflammatory response. Altogether, the results reveal how S. Typhimurium infection alters the gut microbiome composition and prompts changes in the metabolism with a potential interaction between intestinal metabolism and microbiota abundance.

Mulberry is an economically significant crop for the sericulture industry worldwide. Stresses such as drought exposure have a significant influence on plant survival. Metabolome directly reflects plant physiological status; thus, a way to assess this impact is to perform a global metabolomic analysis. This study investigated the effect of drought stress on mulberry Yu-711 metabolic balance using a liquid chromatography-mass spectrometry (LC-MS) based on an untargeted metabolomic approach. For this objective, Yu-711 leaves were subjected to two weeks of drought stress treatment and control without drought stress. Multivariate and univariate statistical analyses highlighted numerous differentially-accumulated metabolic elements as a function of time and treatment. Drought stress led to a more differentiated metabolites response than the control. We found that the levels of total lipids and galactolipids, and phospholipids (PC, PA, PE) were significantly altered, producing 48% of the total differentially expressed metabolites. Fatty acyls were the most abundant lipids expressed and decreased considerably by 73.6%. Prenol lipids class of lipids increased in drought leaves. Other classes of metabolites, including polyphenols( flavonoids and cinnamic acid), organic acid (amino acids), carbohydrates, benzenoids, and organoheterocyclic, all had a dynamic trend in response to the drought stress. However, their levels under drought stress generally decreased significantly compared to the control. These results provide an overview of the metabolic profile of the mulberry plant through differentially-accumulated compounds and provide a better understanding of global plant metabolic changes in defense mechanisms.

To allow for a broad survey of subtle metabolic shifts in wine caused by rootstock and irrigation, an integrated metabolomics-based workflow followed by quantitation was developed. This workflow was particularly useful when applied to a poorly studied variety cv. Chambourcin. Allowing volatile metabolites that otherwise may have been missed with a targeted analysis to be included, this approach allowed deeper modeling of treatment differences which then could be used to identify important compounds. Wines produced on a per vine basis, over two years, were analyzed using SPME-GC-MS/MS. From the 382 and 221 features that differed significantly among rootstocks in 2017 and 2018 respectively, we tentatively identified 94 compounds by library search and retention index, with 22 confirmed and quantified using authentic standards. Own-rooted Chambourcin differed from other root-systems for multiple volatile compounds with fewer dif-ferences among grafted vines. For example, the average concentration of β-Damascenone present in own-rooted vines (9.49 µg/L) was significantly lower in other rootstocks (8.59 µg/L), whereas mean Linalool was significantly higher in 1103P rootstock compared to own-rooted. β-Damascenone was higher in regulated deficit irrigation (RDI) than other treatments. The workflow outlined not only was shown to be useful for scientific investigation, but also in creating a protocol for analysis that would ensure differences of interest to industry are not missed.

In the interest of developing more effective and safer anti-Tuberculosis treatment, we aimed for a better understanding of the antimycobacterial action of ciprofloxacin against Mycobacterium tuberculosis (Mtb). We used GCxGC-TOF-MS and well described metabolomics statistical approaches, to investigate and compare the metabolic profiles of Mtb in the presence and absence of the drug. The metabolites that best describe the differences between the compared groups were identified as markers characterizing the changes induced by ciprofloxacin. Malic acid was ranked as the most significantly altered metabolite marker induced by ciprofloxacin, indicative of an inhibition of the tricarboxylic acid (TCA) and glyoxylate cycle of Mtb. The altered fatty acid, myo-inositol and triacylglycerol metabolism seen in this group, supports the previous observations of ciprofloxacin action on the Mtb cell wall. Furthermore, the altered pentose phosphate intermediates, glycerol metabolism markers, glucose accumulation, and the reduction in the glucogenic amino acids specifically, indicates a flux towards DNA (as well as cell wall) repair, also supporting previous findings of DNA damage caused by ciprofloxacin. This study further provides insights useful for designing network whole-system strategies for the identification of possible modes of actions of various drugs and possibly adaptations by Mtb resulting in resistance.

Turmeric, Curcuma longa L., is a type of medicinal plant characterized by its perennial nature and rhizomatous growth. It is a member of the Zingiberaceae family and is distributed across the world’s tropical and subtropical climates, especially in South Asia. Its rhizomes are highly valued for food supplements, spices, flavoring agents, and yellow dye in South Asia since ancient times. It exhibits a diverse array of therapeutic qualities that encompass its ability to combat diabetes, reduce inflammation, act as an antioxidant, exhibit anticancer properties, and promote anti-aging effects. In this study, organic extracts of C. longa rhizomes were subjected to HPLC separation followed by mass spectrometry analysis. The Global Natural Product Social Molecular Networking (GNPS) approach was utilized for the first time in this ethnobotanically important species to conduct an in-depth analysis of its metabolomes based on their fragments. A total of 30 metabolites including 16 diarylheptanoids, 1 diarylpentanoid, 3 bisabolocurcumin ethers, 4 sesquiterpenoids, 4 cinnamic acid derivatives, and 2 fatty acid derivatives were identified. Among 16 diarylheptanoids identified in this study, five of them are reported for the first time in this species.

Untargeted and targeted approaches are the traditional metabolomics workflows acquired for a wider understanding of the metabolome under focus. Both approaches have their strengths and weaknesses. The untargeted, for example, is maximizing the detection and accurate identification of thousands of metabolites, while the targeted is maximizing the linear dynamic range and quantification sensitivity. These workflows, however, are acquired separately, so researchers compromise either a low-accuracy overview of total molecular changes (i.e., untargeted analysis) or a detailed yet blinkered snapshot of a selected group of metabolites (i.e., targeted analysis) by selecting one of the workflows over the other. In this review, we present a novel single injection simultaneous quantitation and discovery (SQUAD) metabolomics that combines targeted and untargeted workflows. It is used to identify and accurately quantify a targeted set of metabolites. It also allows data retro-mining to look for global metabolic changes that were not part of the original focus. This offers a way to strike the balance between targeted and untargeted approaches in one single experiment and address the two’s limitations. This simultaneous acquisition of hypothesis-led and discovery-led datasets allows scientists to gain more knowledge about biological systems in a single experiment.

Stable isotope-assisted approaches can improve untargeted LC-HRMS metabolomics studies. Here, we demonstrate at the example of chemically stressed wheat that metabolome-wide internal standardization by globally 13C-labeled metabolite extract (GLMe-IS) of experimental-condition-matched biological samples can help to improve coverage of treatment-relevant metabolites and aid in the post-acquisition assessment of putative matrix effects in samples obtained upon different treatments. For this, native extracts of toxin- and mock-treated (control) wheat ears were standardized by the addition of uniformly-13C-labeled wheat ear extracts that were cultivated under similar experimental conditions (toxin-treatment and control) and measured with LC-HRMS. The results show that 996 wheat-derived metabolites were detected with the non-condition-matched 13C-labeled metabolite extract, while another 68 were only covered by the experimental-condition-matched GLMe-IS. Additional testing is performed with the assumption that GLMe-IS enables compensation for matrix effects. Although on average no severe matrix differences between both experimental conditions were found, individual metabolites may be affected as is demonstrated by wrong decisions with respect to the classification of significantly altered metabolites. When GLMe-IS was applied to compensate for matrix effects, 272 metabolites showed significantly altered levels between treated and control samples, 42 of which would not have been classified as such without GLMe-IS.

Ketogenic diet (KD) is getting in the focus as auxiliary cancer therapy, since it provides sufficient energy supply for healthy cells, while impairing energy production in tumor cells underlying the Warburg effect. Thereby, it can assist in inhibiting tumor growth and simultaneously counteract cachexia, which is frequently observed in cancer patients under chemotherapy. In order to provide molecular evidence for the proposed synergistic inhibition of tumor growth, we applied untargeted quantitative metabolome analysis on a breast cancer xenograft mouse model. Healthy mice and such bearing breast cancer xenografts and receiving chemotherapy were compared after treatment with control diet and KD. Metabolomic profiling was performed on plasma samples, applying high-performance liquid chromatography coupled to tandem mass spectrometry. Statistical analysis revealed metabolic fingerprints comprising numerous significantly regulated features in the group of mice bearing breast cancer. This fingerprint disappeared after treatment with KD, resulting in recovery to the metabolic status observed in healthy mice receiving control diet. Moreover, amino acid metabolism as well as fatty acid transport were found to be affected by both, the tumor and the applied KD. Our results provide clear evidence of a significant molecular effect of KD in the context of tumor growth inhibition.

The breeding of stress-tolerant cultivated plants that would allow for a reduction in harvest losses and undesirable decrease in quality attributes requires a new quality of knowledge on molecular markers associated with relevant agronomic traits, on quantitative metabolic responses of plants on stress challenges, and on the mechanisms controlling the biosynthesis of these molecules. By combining metabolomics with genomics, transcriptomics and proteomics datasets a more comprehensive knowledge of the composition of crop plants used for food or animal feed is possible. In order to optimize crop trait developments, to enhance crop yields and quality, as well as to guarantee nutritional and health factors, that provides the possibility to create functional food or feedstuffs, the knowledge about the plants’ metabolome is crucial. Next to classical metabolomics studies, this review focusses on several metabolomics based working techniques, such as sensomics, lipidomics, hormonomics and phytometabolomics, which were used to characterize metabolome alterations during abiotic and biotic stress, to find resistant food crops with a preferred quality or at least to produce functional food crops are highlighted.