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Peptidomics is a powerful set of tools for the identification, structural elucidation and discovery of novel regulatory peptides and for monitoring the degradation pathways of structurally and catalytically important proteins. Amphibian skin secretions, arising from specialized granular glands, often contain complex peptidomes containing many components of entirely novel structure and unique site‐substituted analogues of known peptide families. Following the discovery that the granular gland transcriptome is present in such secretions in a PCR‐amenable form, we designed a strategy for peptide structural characterization involving the integration of ‘shotgun’ cloning of cDNAs encoding peptide precursors, deduction of putative bioactive peptide structures, and confirmation of these structures using tandem MS/MS sequencing. Here, we illustrate this strategy by means of elucidation of the primary structures of nigrocin‐2 homologues from the defensive skin secretions of four species of Chinese Odorrana frogs, O. schmackeri, O. livida, O. hejiangensis and O. versabilis. Synthetic replicates of the peptides were found to possess antimicrobial activity. Nigrocin‐2 peptides occur widely in the skin secretions of Asian ranid frogs and in those of the Odorrana group, and are particularly well‐represented and of diverse structure in some species. Integration of the molecular analytical technologies described provides a means for rapid structural characterization of novel peptides from complex natural libraries in the absence of systematic online database information.

Purpose: High cardiorespiratory capacity is a key determinant of human performance and life expectancy; however, the underlying mechanisms are not fully understood. The objective of this pilot study was to investigate biochemical signatures of endurance-performance athletes using high-resolution nontargeted metabolomics. Methods: Elite long-distance runners with similar training and anthropometrical records were studied. After athletes’ maximal oxygen consumption () was measured, they were divided into 2 groups: low (<65 mL·kg−1·min−1, n = 7) and high (>75 mL·kg−1·min−1, n = 7). Plasma was collected under basal conditions after 12 hours of fasting and after a maximal exercise test (nonfasted) and analyzed by high-resolution LC–MS. Multivariate and univariate statistics were applied. Results: A total of 167 compounds were putatively identified with an LC–MS-based metabolomics pipeline. Partial least-squares discriminant analysis showed a clear separation between groups. Significant variations in metabolites highlighted group differences in diverse metabolic pathways, including lipids, vitamins, amino acids, purine, histidine, xenobiotics, and others, either under basal condition or after the maximal exercise test. Conclusions: Taken together, the metabolic alterations revealed in the study affect cellular energy use and availability, oxidative stress management, muscle damage, central nervous system signaling metabolites, nutrients, and compound bioavailability, providing new insights into metabolic alterations associated with exercise and cardiorespiratory fitness levels in trained athletes.

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Verhaert, P. (2013). The chains of the heterodimeric amphibian skin antimicrobial peptide, distinctin, are encoded by separate messenger RNAs.

Considering the functions of these proteins our results support that the intermediary metabolism and respiration were affected by EMB and this disturbance provided proteins that could be explored as additional targets for this drug.

Hutchinson-Gilford Progeria Syndrome (HGPS) is an extremely rare genetic disorder. HGPS children present a high incidence of cardiovascular complications along with altered metabolic processes and accelerated aging process. No metabolic biomarker is known and the mechanisms underlying premature aging are not fully understood. The present study analysed plasma from six HGPS patients of both sexes (7.7±1.4 years old; mean±SD) and eight controls (8.6±2.3 years old) by LC-MS/MS in high-resolution non-targeted metabolomics (Q-Exactive Plus). Several endogenous metabolites with statistical difference were found. Multivariate statistics analysis showed a clear separation between groups. Potential novel metabolic biomarkers are identified using the multivariate area under ROC curve (AUROC) based analysis, showing an AUC value higher than 0.80 using only two metabolites, and reaching 1.00 when increasing the number of metabolites in the AUROC model. Targeted metabolomics was used to validate some of the metabolites identified by the non-targeted method. Taken together, changed metabolic pathways in that panel involve sphingolipid, amino acid, and oxidation of fatty acids among others. In conclusion our data show significant alterations in cellular energy use and availability, in signal transduction, and in lipid metabolites, creating new insights on metabolic alterations associated with premature aging.

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