Direct Infusion Metabolomics of the Photosystem and Chlorophyll Related Metabolites within a Drought Tolerant Plant Introduction of Glycine max

Drought is the most prolific form of abiotic stress that legumes and cereal plants alike can endure, and the planting of an improper cultivar at the beginning of a season can cause unexpected losses up to fifty percent under water deficient conditions. Herein, a plant introduction (PI) of an exotic cultivar of soybean (Glycine max), PI 567731, which demonstrates a slow wilting (SW) canopy phenotype in maturity group III, was profiled under drought conditions in field trials in Missouri against a drought susceptible check cultivar, Pana. Metabolomic profiling was carried out on samples of leaves from each of these cultivars at V5 and R2 growth stages both while irrigated and while under drought stress for three weeks. PI 567731 was observed to have differential phytochemical content, and enhanced levels of chlorophyll (Chl) a/b and pheophytin (Pheo) were profiled by direct infusion electrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Indicating drought induced changes of the photosystem and photosynthetic capabilities alongside water preservation strategies are important within the SW phenotype drought response. Subsequent multivariate analysis was able to form predictive models, encompassing the variance of growth and drought stress of the cultivar. Moreover, the existence of unique Chl-related metabolites (CRM) (m/z > 900) were confirmed through tandem mass spectrometry. The resultant coordination of fatty acids to the core of the porphyrin ring was observed and played an unknown role in the proliferation of the photosynthesis. However, the relative ratio of the most abundant CRM is undisturbed by drought stress in PI 567731, in contrast to the drought susceptible cultivar. These results provide key insights into drought related metabolic mechanisms.

Biochemical Signatures in Growth Hormone Deficiency: a Pilot Study Using Metabolomics Approaches by Direct Infusion-mass Spectrometry

Purpose: The discovery of biomarkers to detect growth hormone deficiency (GHD) and monitor growth hormone replacement therapy (GHRT) remains challenging. Among “omics” technologies used for screening biomarkers, metabolomics stands out as a powerful tool for large-scale identification and quantification of small molecules present in biological matrixes. Metabolomic profiles allow us to infer the phenotypic state; therefore, metabolomics is a great ally in investigating biomarkers and understanding biological processes. Methods: In this study, global metabolomics (N = 39; range scan 50-600 m/z) and lipidomics (N = 36; range scan 50-1500 m/z) approaches were performed by high-resolution direct infusion-mass spectrometry. Partial least-square discriminant analysis (PLS-DA) models were used for data-driven diagnosis of GHD and evaluation of GHRT (VIP score >1.5). Cross-validation, permutation test, and ROC curves confirmed the predictive accuracy of PLS-DA models. The features were annotated using accurate mass measurements matched against the metabolomics database. Results: Data analysis revealed changes in the class of proteinogenic/glycogenic acids, carnitines, n-acyl-amines, unsaturated fatty acids, and sulfur amino acids, and pathway analyzes revealed changes in glycerophospholipid metabolism. Regardless of GH therapy, GHD individuals remain with changes in lipids and amino acids compared to healthy control. Conclusion: GHRT influences the metabolism status of GHD patients in order to compensate for dysregulations caused by GHD. The data has corroborated the action of GHRT and indicated new potential biomarkers for treatment follow-up.

Paper Spray Ionisation Ion Mobility Mass Spectrometry of Sebum Classifies Biomarker Classes for the Diagnosis of Parkinson’s Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder and identification of robust biomarkers to complement clinical diagnosis will accelerate treatment options. Here we demonstrate the use of direct infusion of sebum from skin swabs using paper spray ionisation coupled with ion mobility mass spectrometry (PS-IM-MS) to determine the regulation of molecular classes of lipids in sebum that are diagnostic of PD. A PS-IM-MS method for sebum samples that takes three minutes per swab was developed and optimised. The method was applied to skin swabs collected from 150 people and elucidates ~ 4200 features from each subject which were independently analysed. The data included high molecular weight lipids (>600 Da.) that differ significantly in the sebum of people with PD. Putative metabolite annotations of several lipid classes, predominantly triglycerides and larger acyl glycerides, were obtained using accurate mass, tandem mass spectrometry and collision cross section measurements.

PSV-B-17 Additional dietary choline increases serum metabolites as determined by direct infusion mass spectrometry in post-gonadectomy kittens

This study aimed to investigate changes in serum metabolites using direct infusion mass spectrometry (Di-MS) after 12 weeks with or without additional choline in growing, post-gonadectomy kittens. The present study was approved by the University of Guelph Animal Care Committee (AUP#4118). Intact, male kittens (3-months old; n = 15) were fed a base-diet to growth requirements (3310mg choline/kg DM) over an 11-week acclimation. Kittens were gonadectomized (week 1) and assigned to base-diet (n = 7) or base-diet with 300mg/kgBW0.75 additional choline (n = 8) and fed to mimic ad libitum food intake (3 meals totaling thrice daily requirements) for 12-weeks. Fasted serum samples were obtained and analyzed for 130 metabolites via Di-MS (week 0 and 12). The proc GLIMMIX procedure (SAS) was used to analyze differences between groups as a repeated measure. Additional choline resulted in higher serum concentrations of one-carbon metabolites such as methionine, serine, betaine, and sarcosine (P < 0.05). As expected, serum concentrations of phosphatidylcholines increased with additional choline, as did serum concentrations of lysophosphatidylcholines and sphingomyelins, compared to no additional choline (P < 0.05). There was minimal impact on acyl carnitines with a decrease in medium length acyl carnitines (P < 0.05). Additionally, there was an increase in serum concentrations of spermine, trans hydroxyproline, methionine sulfoxide, proline, and indole acetic acid, and a decrease in serum trimethylamine N-Oxide compared to control (P < 0.05). Effects of growth stage or gonadectomy may have resulted in increased serum amino acid concentrations such as asparagine, glutamine, glutamic acid, histidine, lysine, methionine, threonine, and tyrosine in both groups (P < 0.05). These results may indicate benefits for providing additional choline to post-gonadectomy kittens on one-carbon metabolism and fatty acid oxidation which could promote healthy weight and body condition. However, more research is warranted to further understand choline’s role in energy balance and its potential in prevention and treatment of feline obesity.