Gas Chromatography Time-of-flight Mass Spectrometry Research Articles

Metabolomics Responses of Pearl Oysters (Pinctada fucata martensii) Fed a Formulated Diet Indoors and Cultured With Natural Diet Outdoors.

Natural disasters and environmental pollution are the main problems in traditional offshore cultivation. While culturing pearl oysters through industrial farming can avoid these problems, food availability in this case is limited. This study compares the metabolomics responses of pearl oysters, Pinctada fucata martensii, fed a formulated diet indoors with those of oysters cultured with natural diet outdoors by using a gas chromatography time-of-flight mass spectrometry (GC-TOF/MS)-based metabolomics approach. The animals were divided into two groups as follows: the experimental group (EG) was fed a formulated diet indoors and the control group (CG) was cultured with natural diet outdoors. After 45 days of feeding, the survival rate of EG was significantly higher than that of CG. The absolute growth rate (AGR) of the total weight of EG did not significantly differ from that of CG, but the AGRs of the shell length, shell height, and shell width of CG were significantly higher than those of EG. EG showed significantly higher amylase activities than CG, and the hexokinase and glucose-6-phosphate isomerase concentrations of the former were significantly lower than those of the latter. Metabolomics revealed 125 metabolites via mass spectrum matching with a spectral similarity value > 700 in the hepatopancreas, and 48 metabolites were considered to be significantly different between groups (VIP > 1 and P < 0.05). Pathway analysis results indicated that these significantly different metabolites were involved in 34 pathways. Further integrated key metabolic pathway analysis showed that, compared with CG, EG had lower capabilities for cysteine and methionine metabolism, sulfur metabolism, and starch and sucrose metabolism. This study demonstrated that the formulated diet could be an excellent substitute for natural diet; however, its nutrients were insufficient. Effective strategies should be developed to enhance the utilization of formulated diets.

Gut microbial and metabolomic profiles after fecal microbiota transplantation in pediatric ulcerative colitis patients.

Ulcerative colitis is a chronic inflammatory disease of the colon that carries a significant disease burden in children. Therefore, new therapeutic approaches are being explored to help children living with this disease. Fecal microbiota transplantation (FMT) has been successful in some children with ulcerative colitis. However, the mechanism of its therapeutic effect in this patient population is not well understood. To characterize changes in gut microbial and metabolomic profiles after FMT, we performed 16S rRNA gene sequencing, shotgun metagenomic sequencing, virome analysis and untargeted metabolomics by gas chromatography-time of flight-mass spectrometry on stool samples collected before and after FMT from four children with ulcerative colitis who responded to this treatment. Alpha diversity of the gut microbiota increased after intervention, with species richness rising from 251 (S.D. 125) to 358 (S.D. 27). In responders, the mean relative abundance of bacteria in the class Clostridia shifted toward donor levels, increasing from 33% (S.D. 11%) to 54% (S.D. 16%). Patient metabolomic and viromic profiles exhibited a similar but less pronounced shift toward donor profiles after FMT. The fecal concentrations of several metabolites were altered after FMT, correlating with clinical improvement. Larger studies using a similar multi-omics approach may suggest novel strategies for the treatment of pediatric ulcerative colitis.

Analysis of Metabolites in White Flowers of Magnolia Denudata Desr. and Violet Flowers of Magnolia Liliiflora Desr.

A total of seven phenolics and 44 metabolites was profiled in white flowers of Magnolia denudata and violet flowers of Magnolia liliiflora using high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOFMS). Seven phenylpropanoid compounds were identified in white flowers by liquid chromatography mass spectrometry (LC-MS). An HPLC analysis showed that phenylpropanoid accumulation in violet flowers was 1.48 times higher than that in white flowers. Furthermore, superoxide dismutase (SOD)-like activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were determined to investigate the antioxidant properties of secondary metabolites in different flowers. Violet flowers showed higher SOD-like and DPPH activity than white flowers. In addition, anti-inflammatory activity measured using a nitric oxide assay was higher in violet flowers than in white flowers. Our results provide valuable information on the relationship between primary and secondary metabolites, and synergistic antioxidant and anti-inflammatory properties derived from phenolic compounds in different colored flowers.

Metabolomic Changes in Sogatella furcifera under Southern rice black-streaked dwarf virus Infection and Temperature Stress.

Southern rice black-streaked dwarf virus (SRBSDV) is a devastating newly emerged rice reovirus in Eastern and Southeastern Asia transmitted by a long-distance migratory pest, the white-backed planthopper (WBPH). We previously showed that SRBSDV infection decreased the cold tolerance but improved the heat tolerance of its vector, WBPH. Comparative metabolomic analysis was used to explore the potential mechanisms underlying these changes in temperature stress response. Fourth-generation WBPH nymphs were treated with SRBSDV and/or extreme temperature stress and were analyzed using gas chromatography-time of flight-mass spectrometry. A total of 605 distinguishable peaks were identified and 165, 207, and 202 differentially accumulated metabolites were identified in WBPH after virus infection, cold, or heat stress, respectively. The nucleic acids and fatty acids were the major categories of metabolites regulated by SRBSDV infection, whereas temperature stress regulated tricarboxylic acid cycle compounds, sugars, and polyols. For the WBPH samples infected with SRBSDV and subjected to temperature stress, amino acids, sugars, and polyols were the most significant regulated metabolites. The metabolomics study suggests that SRBSDV may influence the extreme temperature tolerance of WBPH by regulating the accumulation of amino acids, sugars, and polyols in the insect body.

Metabolic Profiling of Multiorgan Samples: Evaluation of MODY5/RCAD Mutant Mice.

In the present study, we performed a metabolomics analysis to evaluate a MODY5/RCAD mouse mutant line as a potential model for HNF1B-associated diseases. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) of gut, kidney, liver, muscle, pancreas, and plasma samples uncovered the tissue specific metabolite distribution. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) was used to identify the differences between MODY5/RCAD and wild-type mice in each of the tissues. The differences included, for example, increased levels of amino acids in the kidneys and reduced levels of fatty acids in the muscles of the MODY5/RCAD mice. Interestingly, campesterol was found in higher concentrations in the MODY5/RCAD mice, with a four-fold and three-fold increase in kidneys and pancreas, respectively. As expected, the MODY5/RCAD mice displayed signs of impaired renal function in addition to disturbed liver lipid metabolism, with increased lipid and fatty acid accumulation in the liver. From a metabolomics perspective, the MODY5/RCAD model was proven to display a metabolic pattern similar to what would be suspected in HNF1B-associated diseases. These findings were in line with the presumed outcome of the mutation based on the different anatomy and function of the tissues as well as the effect of the mutation on development.

Discovery of High-Abundance Diamondoids and Thiadiamondoids and Severe TSR Alteration of Well ZS1C Condensate, Tarim Basin, China

Diamondoid and thiadiamondoid compounds in crude oils are generally related to thermal cracking and TSR (thermochemical sulfate reduction). Diamondoids occur in almost all petroleum, but usually with low concentration (2 μg/g or less). The abundance of thiadiamondoid reflects the extent of TSR, which is rarely detected >20 μg/g. Recently, a commercial oil-gas production has been discovered in the deep Cambrian strata of the Tarim Basin, China. The condensate sample conducted with GC×GC-TOFMS (2D gas chromatography/time-of-flight mass spectrometry) analysis revealed that diamondoids series contains 281 components with a total concentration of 187 mg/g, and the thiadiamondoids series contains 267 components with a total concentration of 28 mg/g, respectively. We reported the identification of 14 compounds, including 11 dithiatriamantanes and 3 tetrathiadiamantanes for the first time in natural oils. According to the comprehensive analysis of sulfur and carbon isotopes and hydrocarbon composition of the cond...

Effects of legacy metabolites from previous ecosystems on the environmental metabolomics of the brine of Lake Vida, East Antarctica

Lake Vida, located in a closed basin in the McMurdo Dry Valleys, East Antarctica, permanently encapsulates an interstitial anoxic, aphotic, cold (−13 °C), brine ecosystem within 27+ m of ice. Metabolically active, but cold-limited, slow-growing bacteria were detected in the brine. Lake Vida brine is derived from the evaporation of a body of water that occupied the same basin prior to ∼2800 years ago. The characteristics of this body of water changed over time and, at one point, likely resembled other modern well-studied perennial ice-covered lakes of the Dry Valleys. We characterized the dichloromethane-extractable fraction of the environmental metabolome of Lake Vida brine in order to constrain current and ancient biogeochemical processes. Analysis of the dichloromethane-extract of Lake Vida brine by gas chromatography-mass spectrometry and comprehensive multidimensional gas chromatography-time of flight-mass spectrometry reveals the presence of legacy compounds (i.e. diagenetic products of chlorophylls and carotenoids) deriving from photosynthetic algae and anaerobic, anoxygenic photosynthetic bacteria. This legacy component dilutes the environmental signal of metabolites deriving from the extant bacterial community. The persistence of legacy metabolites (paleometabolites), apparent in Lake Vida brine, is a result of the slow turnover rates of the extant bacterial population due to low metabolic activities caused by the cold limitation. Such paleometabolites may also be preserved in other cold-limited or nutrient-depleted slow-growing ecosystems. When analyzing ecosystems with low metabolic rates, the presence of legacy metabolites must first be addressed in order to confidently recognize and interpret the environmental metabolome of the extant ecosystem.

Volatiles Mediated Interactions Between Aspergillus oryzae Strains Modulate Morphological Transition and Exometabolomes.

Notwithstanding its mitosporic nature, an improbable morpho-transformation state i. e., sclerotial development (SD), is vaguely known in Aspergillus oryzae. Nevertheless an intriguing phenomenon governing mold's development and stress response, the effects of exogenous factors engendering SD, especially the volatile organic compounds (VOCs) mediated interactions (VMI) pervasive in microbial niches have largely remained unexplored. Herein, we examined the effects of intra-species VMI on SD in A. oryzae RIB 40, followed by comprehensive analyses of associated growth rates, pH alterations, biochemical phenotypes, and exometabolomes. We cultivated A. oryzae RIB 40 (S1VMI: KACC 44967) opposite a non-SD partner strain, A. oryzae (S2: KCCM 60345), conditioning VMI in a specially designed “twin plate assembly.” Notably, SD in S1VMI was delayed relative to its non-conditioned control (S1) cultivated without partner strain (S2) in twin plate. Selectively evaluating A. oryzae RIB 40 (S1VMI vs. S1) for altered phenotypes concomitant to SD, we observed a marked disparity for corresponding growth rates (S1VMI < S1)7days, media pH (S1VMI > S1)7days, and biochemical characteristics viz., protease (S1VMI > S1)7days, amylase (S1VMI > nS1)3–7days, and antioxidants (S1VMI > S1)7days levels. The partial least squares—discriminant analysis (PLS-DA) of gas chromatography—time of flight—mass spectrometry (GC-TOF-MS) datasets for primary metabolites exhibited a clustered pattern (PLS1, 22.04%; PLS2, 11.36%), with 7 days incubated S1VMI extracts showed higher abundance of amino acids, sugars, and sugar alcohols with lower organic acids and fatty acids levels, relative to S1. Intriguingly, the higher amino acid and sugar alcohol levels were positively correlated with antioxidant activity, likely impeding SD in S1VMI. Further, the PLS-DA (PLS1, 18.11%; PLS2, 15.02%) based on liquid chromatography—mass spectrometry (LC-MS) datasets exhibited a notable disparity for post-SD (9–11 days) sample extracts with higher oxylipins and 13-desoxypaxilline levels in S1VMI relative to S1, intertwining Aspergillus morphogenesis and secondary metabolism. The analysis of VOCs for the 7 days incubated samples displayed considerably higher accumulation of C-8 compounds in the headspace of twin-plate experimental sets (S1VMI:S2) compared to those in non-conditioned controls (S1 and S2—without respective partner strains), potentially triggering altered morpho-transformation and concurring biochemical as well as metabolic states in molds.

Untargeted metabolomics reveals a new mode of action of pretomanid (PA-824)

Pretomanid is a promising anti-tubercular drug currently at clinical phase III, but its mechanisms of action are currently unclear. This study aimed to: (i) reveal the metabolome of Mycobacterium smegmatis under pretomanid treatment; (ii) compare major sources of metabolite variation in bacteria treated with pretomanid treatment and other antibiotics; and (iii) to target metabolites responsible for the killing activity of pretomanid in mycobacteria. Untargeted high-resolution metabolite profiling was carried out using flow infusion electrospray ion high resolution mass spectrometry (FIE-HRMS) to identify and quantify metabolites. The identification of key metabolites was independently confirmed by gas-chromatography time-of flight mass spectrometry (GC-tofMS) in comparison to standards. Pretomanid treatments generated a unique distinctive metabolite profile when compared to ampicillin, ethambutol, ethionamide, isoniazid, kanamycin, linezolid, rifampicin and streptomycin. Metabolites which differed significantly only with pretomanid treatment were identified and mapped on to bacterial metabolic pathways. This targeted the pentose phosphate pathway with significant accumulation seen with fructose-6-phosphate, ribose-5-phosphate and glyceraldehyde-3-phosphate. These effects were linked to the accumulation of a toxic metabolite methylglyoxal. This compound showed significant antimicrobial activity (MIC 0.65 mM) against M. smegmatis.

Alteration of metabolite profiling by cold atmospheric plasma treatment in human myeloma cells

BackgroundDespite new progress of chemotherapy in multiple myeloma (MM) clinical treatment, MM is still a refractory disease and new technology is needed to improve the outcomes and prolong the survival. Cold atmospheric plasma is a rapidly developed technology in recent years, which has been widely applied in biomedicine. Although plasma could efficiently inactivate various tumor cells, the effects of plasma on tumor cell metabolism have not been studied yet.MethodsIn this study, we investigated the metabolite profiling of He plasma treatment on myeloma tumor cells by gas-chromatography time-of-flight (GC-TOF) mass-spectrometry. Meanwhile, by bioinformatic analysis such as GO and KEGG analysis we try to figure out the metabolism pathway that was significantly affected by gas plasma treatment.ResultsBy GC-TOF mass-spectrometry, 573 signals were detected and evaluated using PCA and OPLS-DA. By KEGG analysis we listed all the differential metabolites and further classified into different metabolic pathways. The results showed that beta-alanine metabolism pathway was the most significant change after He gas plasma treatment in myeloma cells. Besides, propanoate metabolism and linoleic acid metabolism should also be concerned during gas plasma treatment of cancer cells.ConclusionsCold atmospheric plasma treatment could significantly alter the metabolite profiling of myeloma tumor cells, among which, the beta-alanine metabolism pathway is the most susceptible to He gas plasma treatment.

Diurnal changes in C[sbnd]N metabolism and response of rice seedlings to UV-B radiation

Plants regulate a number of primary metabolites, including carbohydrates, organic acids, and amino acids, in response to UV-B radiation. Therefore, it is essential to understand the time-dependent response of rice plants to UV-B stress. This study focused on the response of plants to UV-B at different leaf developmental phases (emerging, growing, and maturing) in an attempt to fully comprehend the metabolic shift. We analyzed the expression levels of genes related to starch/sucrose metabolism in the leaf blades of rice seedlings (Oryza sativa L. “Saechuchenog”) exposed to UV-B irradiation for short (1 day) and long terms (5 days) using quantitative real-time polymerase chain reaction. We also examined the diurnal variations in the contents of primary metabolites using an established GCTOF-MS (gas chromatography time of flight-mass spectrometry) method. The results showed that the levels of primary metabolites were largely dependent upon the diurnal rhythm and leaf developmental phase. The young leaves (sink) produced and accumulated starch rather than sucrose. The short-term (4 h, 1 day) UV-B exposure inhibited sucrose synthesis, which could be the first target of UV-B radiation. Following short- and long-term (5 days) exposure to UV-B radiation, the dynamic response of primary metabolites was evaluated. It was found that the content of carbohydrates decreased throughout the period of exposure to UV-B stress, especially in terms of sucrose concentration. However, the content of the majority of amino acids increased after an early decrease. Our data revealed that the metabolic response, as well as the gene expression, differed with the period (intensity) of exposure to UV-B radiation and with the phase of leaf development. These findings provide new insights for a better understanding of the metabolic response of a variety of plant species exposed to a wide range of UV-B radiation.

Metabolic Profiling and Chemical-Based Antioxidant Assays of Green and Red Lettuce (Lactuca sativa)

Lettuce ( Lactuca sativa) is an important leaf vegetable crop worldwide. The total phenolic content was higher in the red skirt methanol extracts with a level of 64.9 ± 0.3 mg GA/g, and phenolic content of green skirt was 49.4 ± 0.3 mg GA/g. The total flavonoid content in the methanol extract of red skirt showed the highest concentration (291.6 ± 9.0 mg rutin/g), followed by green skirt (223 ± 9.8 mg rutin/g). The red skirt showed a higher content of anthocyanin (23.7 ± 0.8 mg/100 g) compared to the green skirt (7.4 ± 0.9 mg/100 g). Seven carotenoids i.e., lutein, β–carotene, 9 Z–β–carotene, 13 Z–β–carotene, violaxanthin, zeaxanthin, and α–carotene were detected in both cultivars. The polar metabolites are strongly associated with the metabolites that participate in the TCA cycle. Correlations between primary and secondary metabolites were easily achieved by gas chromatography-time-of-flight mass spectrometry (GC-TOFMS)-based metabolite profiling method. Red skirt methanol extract showed 77.5 ± 0.4% 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity, 50.8 ± 0.8% hydrogen peroxide radical scavenging assay and absorbance value (0.052) reducing power assay at 250 μL/mL, having significantly higher activity than the green skirt extract. The red lettuce extract also showed higher levels of phenolic compounds, flavonoids, and anthocyanins, and it possesses more antioxidant properties compared to the green skirt extract. In this study we compared two cultivars of lettuce, red skirt and green skirt, for various nutritional parameters and to understand the association of secondary metabolites with their corresponding primary metabolites. From the overall analysis, it is confirmed that GC-TOFMS-based metabolite profiling is an appropriate method for determining biochemical reactions and also acts as a combined resource to understand primary and secondary metabolism.

Comprehensive chemical characterization of lubricating oils used in modern vehicular engines utilizing GC × GC-TOFMS

A number of major studies have demonstrated that the SVOC (Semi-volatile organic compounds) within engine emissions derive predominantly from unburned fuel and lubricants, and are a major contributor to primary atmospheric aerosol containing thousands of organic compounds. The GC × GC-ToF-MS (2 dimensional Gas Chromatography – Time of Flight – Mass Spectrometry) comprehensive analytical technique was utilized in this study, to resolve the complex mixtures and characterize the SVOC content in eight different commercial lubricants, including 5 W30 synthetic and semi-synthetic, mineral and base oil. In order to quantify the aliphatic isomers, which comprise the largest component of the lubricants, a TIC-M.Q./Mass (Total ion current ratio to the molar quantity/mass) method has been developed. The TIC intensity was observed to be proportional to the molar quantity of n-alkanes for carbon number <C25, while being linear to the mass response for these aliphatic compounds with carbon number >C25. Additionally, the TIC intensity of the alkyl-cyclohexanes under the identical retention indices were found to have an equivalent response to those of the n-alkanes, showing that the quantitative calibrations derived for the n-alkane series could be applied to estimate the concentrations of isomeric aliphatic compounds with similar molecular weight. Furthermore, a mesh method was introduced to group the alkane species (n-alkanes, branched alkanes and cyclic alkanes etc.), combining with the use of a soft EI (electron impact) ionization (14 eV) to retain the distinct identity of the isomers with less fragmentation, which allowed the TIC-M.Q./Mass methodology to integrate all the constitutional isomers present in the lubricating oil samples. By utilizing this methodology, compositions from different samples were comprehensively compared, leading to the following conclusions: 1) the synthetic and semi-synthetic oils contained a larger abundance of HMW (high molecular weight) aliphatic compounds (carbon number C24–C29), while those in the LMW (low molecular weight range, carbon number C18–C25) were predominant in the mineral and base oil; 2) cycloalkanes were predominant in the synthetic and semi-synthetic oils; whereas the branched alkanes were more prominent in the mineral and base oils; 3) for lubricants used for a short period, a slight increase of LMW compounds was observed, while the HMW compounds underwent a decrease, whereas, there was an overall mass reduction for all the aliphatic compounds detected in the oil samples used for six-months.

Gas chromatography-time of flight/mass spectrometry-based metabonomics of changes in the urinary metabolic profile in osteoarthritic rats.

The aim of the present study was to explore changes in the urinary metabolic spectrum in rats with knee osteoarthritis, using gas chromatography-time of flight/mass spectrometry (GC-TOF/MS) to determine the metabonomic disease pathogenesis. Sprague-Dawley rats were randomly divided into the control and model groups (n=8/group), and 20 µl of 4% papain and 0.03 M L-cysteine was injected into the right knee on days 1, 3 and 7 to establish the knee osteoarthritis model. Following 14 days, urine was collected over 12 h and cartilage ultrastructural damage was assessed by hematoxylin-eosin staining. GC-TOF/MS, combined with principal component analysis, partial least squares discriminant modeling and orthogonal partial least squares discriminant modeling, was used to analyze the changes in the metabolic spectrum trajectory and to identify potential biomarkers and their related metabolic pathways. Compared with the control group, the synovial cell lining of the knee joint exhibited proliferation, inflammatory cell infiltration and collagen fiber hyperplasia in the knee osteoarthritis group. A total of 23 potential biomarkers were identified, including alanine, α-ketoglutarate, asparagine, maltose and glutamine. Furthermore, metabolomic pathogenesis of osteoarthritis may be related to disorders of amino acid metabolism, energy metabolism, fatty acid metabolism, vitamin B6 metabolism and nucleic acid metabolism.

Postoperative Delirium Development Associated with Metabolic Alterations Following Hemi-Arthroplasty in Elderly

Background: Postoperative delirium (POD) is a common and harmful complication following surgery in elderly and possible link between metabolic changes during perioperative period and POD development is yet to be investigated. Methods: A nested case-control study was performed through metabolomics to find out the metabolic abnormalities between patients with and without POD. Elderly patients with hip fracture who had hemi-arthroplasty were recruited and their delirious states were assessed for three days after surgery. Simultaneously, fasting blood samples were collected on the morning of surgery and on the first postoperative day. Ultimately, 244 elderly patients who met the inclusion and exclusion criteria completed our observations. The blood samples from 60 patients with POD and 60 matched controls were analyzed using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). Findings: Sixty patients (24.6%) developed POD. Eighteen metabolites differed between the 2 groups before surgery, and twenty-three metabolites differed between the 2 groups after surgery. Similarly, thirty metabolites in POD group differed before and after surgery, and thirty-two metabolites in NPOD (Non-POD) group differed before and after surgery. After retrieved KEGG database, our data indicated that, in POD group, ω3 and ω6 fatty acids were lower than NPOD group at both before and after surgery, intermediates of tricarboxylic cycle were lower than NPOD group but products of glycolysis were higher than NPOD group after surgery, branched-chain amino acids (BCAAs) / aromatic amino acids (AAAs) ratio was lower than NPOD group after surgery. Interpretation: The metabolic abnormalities, including deficiencies of ω3 and ω6 fatty acids, abnormal oxygen metabolism, metabolic imbalances in aromatic and branched-chain amino acids, may potentially diminish the brain's inherent protective capacity and hence could contribute to the POD development. Funding Statement: This work was supported by grants from the Shanghai Municipal Commission of Health and Family Planning Foundation for Key Developing Disciplines (2015ZB0103) and the Shanghai Jiao Tong University Biomedical Engineering Cross Research Foundation (YG2015MS15). Declaration of Interests: The authors report no conflicts of interest. Ethics Approval Statement: The study was approved by the Ethics Committee of Shanghai Sixth People’s Hospital affiliated with Shanghai Jiao Tong University (Shanghai, China) and was registered (ChiCTR-CPC-15006141). Written informed consent was obtained from all the participants prior to the study.

Obesity-Associated Metabolic Signatures Correlate to Clinical and Inflammatory Profiles of Asthma: A Pilot Study.

PurposeObesity is associated with metabolic dysregulation, but the underlying metabolic signatures involving clinical and inflammatory profiles of obese asthma are largely unexplored. We aimed at identifying the metabolic signatures of obese asthma.MethodsEligible subjects with obese (n = 11) and lean (n = 22) asthma underwent body composition and clinical assessment, sputum induction, and blood sampling. Sputum supernatant was assessed for interleukin (IL)-1β, -4, -5, -6, -13, and tumor necrosis factor (TNF)-α, and serum was detected for leptin, adiponectin and C-reactive protein. Untargeted gas chromatography time-of-flight mass spectrometry (GC-TOF-MS)-based metabolic profiles in sputum, serum and peripheral blood monocular cells (PBMCs) were analyzed by orthogonal projections to latent structures-discriminate analysis (OPLS-DA) and pathway topology enrichment analysis. The differential metabolites were further validated by correlation analysis with body composition, and clinical and inflammatory profiles.ResultsBody composition, asthma control, and the levels of IL-1β, -4, -13, leptin and adiponectin in obese asthmatics were significantly different from those in lean asthmatics. OPLS-DA analysis revealed 28 differential metabolites that distinguished obese from lean asthmatic subjects. The validation analysis identified 18 potential metabolic signatures (11 in sputum, 4 in serum and 2 in PBMCs) of obese asthmatics. Pathway topology enrichment analysis revealed that cyanoamino acid metabolism, caffeine metabolism, alanine, aspartate and glutamate metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, pentose phosphate pathway in sputum, and glyoxylate and dicarboxylate metabolism, glycerolipid metabolism and pentose phosphate pathway in serum are suggested to be significant pathways related to obese asthma.ConclusionsGC-TOF-MS-based metabolomics indicates obese asthma is characterized by a metabolic profile different from lean asthma. The potential metabolic signatures indicated novel immune-metabolic mechanisms in obese asthma with providing more phenotypic and therapeutic implications, which needs further replication and validation.

Urinary Metabolites and Their Link with Premature Arterial Stiffness in Black Boys: The ASOS Study

Background and Aims: Black boys (6–8 years of age) were shown to have higher pulse wave velocity with potential early vascular compromise. We aimed to compare predefined urinary metabolites in black and white boys to explore associations of pulse wave velocity with these metabolites. Methods and Results: We included 40 white and 40 black apparently healthy boys between the ages of 6 and 8 years. Femoral pulse wave velocity was measured along with various metabolites using liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography-time of flight-mass spectrometry (GC-TOF-MS) methods. Pulse wave velocity and diastolic blood pressure were higher in the black compared to the white boys (both p ≤ 0.002). Isovalerylcarnitine was lower and 1-metylhistidine tended to be lower (p = 0.002 and p = 0.073, respectively), whereas L-proline levels tended to be higher (p = 0.079) in the black compared to the white boys. In single, partial, and multiple regression analyses, pulse wave velocity correlated inversely with β-alanine (β = –0.414; p = 0.008) and 1-methylhistidine (β = –0.347; p = 0.032) and positively with L-proline (β = 0.420; p = 0.008), threonic acid (β = 0.977; p = 0.033), and malonic acid (β = 0.348; p = 0.030) in black boys only. Conclusion: Our study is the first to discover the associations of pulse wave velocity with β-alanine, 1-methylhistidine, and L-proline in children from South Africa, which may suggest potential early compromise in cardiac protective metabolic pathways in black boys as young as 6 years of age.

Metabolomic prediction of treatment outcome in pancreatic ductal adenocarcinoma patients receiving gemcitabine.

Resistance to gemcitabine remains a key challenge in the treatment of pancreatic ductal adenocarcinoma (PDAC), necessitating the constant search for effective strategies for a priori prediction of clinical outcome. While the existing studies focused on aberration of drug disposition genes and proteins as molecular predictors of gemcitabine treatment outcomes, the metabolic aberration associated with chemoresistance in clinical PDAC has been neglected. This exploratory study investigated the potential role of tissue metabolomics in characterizing the clinical treatment outcome of gemcitabine therapy. Surgically resected tumors from PDAC patients who underwent gemcitabine-based adjuvant chemotherapy (n = 25) were subjected to metabotyping using gas chromatography/time-of-flight mass spectrometry (GC/TOFMS). A partial least-squares discriminant analysis (PLS-DA) model clearly distinguished patients who had favorable survival [overall survival (OS) > 24 months] from those who exhibited poorer survival (OS < 16 months) (Q 2 = 0.302). Receiver-operating characteristic analysis demonstrated the robustness of the PLS-DA model with an area under the curve of 1. PLS-DA revealed 19 marker metabolites (e.g., lactic acid, proline, and pyroglutamate) that shed insights into the chemoresistance of gemcitabine in PDAC. Particularly, tissue levels of lactic acid complemented transcript expression levels of human equilibrative nucleoside transporter 1 in distinguishing patients according to their overall survival. This work established proof-of-principle for GC/TOFMS-based global metabotyping of PDAC and laid the foundation for future discovery of metabolic biomarkers predictive of gemcitabine resistance in PDAC chemotherapy.

Serum metabonomics study of the hepatoprotective effect of amarogentin on CCl4-induced liver fibrosis in mice by GC-TOF-MS analysis

Amarogentin (AG) is a secoiridoid glycoside that is mainly extracted from the traditional Chinese medicine Swertia and Gentiana, which have been widely used in clinical practice to treat liver disease. However, the exact hepatoprotective mechanism of AG was still looking forward to further elucidation by far. In this study, C57BL/6 mice were divided into the following three groups: control, model and AG. Fibrosis was induced by CCl4. Mice were orally treated with 100mg/kg AG or with normal saline as a control. At the end of the experiment, the validity of the model and the hepatoprotective effects of AG were examined by histopathology and biochemical indicators. Metabonomics technology was further performed to systematically evaluate the endogenous metabolite profiles. Gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) technology with pattern recognition analysis, including principal component analysis (PCA) and orthogonal partial least square discriminant analysis (OPLS-DA), showed a clear separation of the model group and the control group, with the AG treatment group located much closer to the control group than the model group, which was consistent with the results of biochemical and histopathological assays. Moreover, nine potential biomarkers were identified to elucidate the drug mechanism of AG, which may be related to pathways of amino acid and fatty acid metabolism.

Metabolomic analysis of tomato seed germination

IntroductionSeed germination is inherently related to seed metabolism, which changes throughout its maturation, desiccation and germination processes. The metabolite content of a seed and its ability to germinate are determined by underlying genetic architecture and environmental effects during development.ObjectiveThis study aimed to assess an integrative approach to explore genetics modulating seed metabolism in different developmental stages and the link between seed metabolic- and germination traits.MethodsWe have utilized gas chromatography-time-of-flight/mass spectrometry (GC-TOF/MS) metabolite profiling to characterize tomato seeds during dry and imbibed stages. We describe, for the first time in tomato, the use of a so-called generalized genetical genomics (GGG) model to study the interaction between genetics, environment and seed metabolism using 100 tomato recombinant inbred lines (RILs) derived from a cross between Solanum lycopersicum and Solanum pimpinellifolium.ResultsQTLs were found for over two-thirds of the metabolites within several QTL hotspots. The transition from dry to 6 h imbibed seeds was associated with programmed metabolic switches. Significant correlations varied among individual metabolites and the obtained clusters were significantly enriched for metabolites involved in specific biochemical pathways.ConclusionsExtensive genetic variation in metabolite abundance was uncovered. Numerous identified genetic regions that coordinate groups of metabolites were detected and these will contain plausible candidate genes. The combined analysis of germination phenotypes and metabolite profiles provides a strong indication for the hypothesis that metabolic composition is related to germination phenotypes and thus to seed performance.