Sophie Ayciriex

Complex mixtures of contaminants can affect aquatic organisms through diverse modes of action, making extrapolations of laboratory findings to field conditions complex. Here, we show that proteomics combined with active biomonitoring may inform about reprotoxic effects in the sentinel species Gammarus fossarum. Proteomic responses provide information on the diversity of underlying mechanisms and may serve as a sensitive early warning signal of reprotoxicity. Females were exposed in situ in 18 French surveillance sites and analyzed for reproductive end points and proteomic levels in the caeca and the ovaries. This study aimed to assess links between reproductive impairment and molecular responses, using the complementary information provided by both tissues. Protein coexpression analysis identified protein clusters associated with organ functions, reproductive impairments, or field exposure. Several modules were significantly associated with field condition or females’ physiological integrity. Interestingly, we identified a large diversity of biological pathways modulated in impacted females exposed to reprotoxic sites, with reproduction-related proteins as potential early biomarkers of reprotoxicity. These results highlight the relevance of considering field conditions and individual physiology within the eco-exposome framework and demonstrate the value of integrating omics and active biomonitoring to uncover diverse molecular signature behind field-induced reprotoxicity in this sentinel species.

Natural inhibitors of digestive lipases offer promising alternatives to conventional obesity medications. This study screened nine medicinal plant extracts, identifying the ethanolic bark extract of Cinnamomum cassia as the most potent inhibitor for gastric and pancreatic lipases. Using an integrated approach combining bioactivity-guided fractionation and mass spectrometry, we isolated the highly active fraction, F3-1-1, which exhibited dose- and time-dependent inhibitory effects against human and porcine pancreatic lipases, as well as dog gastric lipase (DGL). Further mass spectrometry and peptide mass fingerprint analysis putatively annotated cinncassiol A-19 glucoside as a bioactive constituent. Notably, this compound was likely bound covalently to the catalytic peptide containing the Ser153 residue in DGL, characterized by a mass shift of +553.10 Da. Molecular docking simulations supported these suggestions, demonstrating stable interactions within the catalytic pocket of DGL through hydrogen and hydrophobic bond interactions. These findings highlight C. cassia as a promising source of natural anti-obesity agents.

Natural inhibitors of digestive lipases offer promising alternatives to conventional obesity medications. This study screened nine medicinal plant extracts identifying the ethanolic bark extract of Cinnamomum cassia as the most potent inhibitor for gastric and pancreatic lipases. Using an integrated approach combining bioactivity-guided fractionation and mass spectrometry, we isolated the highly active fraction, F3-1-1, which exhibited dose- and time-dependent inhibitory effects against human and porcine pancreatic lipases, as well as dog gastric lipase (DGL). Further mass spectrometry and peptide mass fingerprint analysis identified cinncassiol A-19 glucoside as the main bioactive constituent. Notably, this compound forms covalent complexes with the catalytic peptide containing the Ser153 residue in DGL, characterized by a mass shift of +553.10 Da. Molecular docking simulations supported these results, demonstrating stable interactions within the catalytic pocket of DGL through hydrogen and hydrophobic bond interactions. These findings highlight C. cassia as a promising source of natural anti-obesity agents.

Although targeted metabolomics using multiple reaction monitoring (MRM) offers high sensitivity, it struggles with multiplexing capacity and retention time drifts. Scout-triggered MRM (stMRM) overcomes these limitations by using reference molecules to dynamically frame the acquisition window. However, establishing comprehensive stMRM assays requires reliable and cost-effective scout compounds that are compatible with multi retention mode of liquid chromatography-mass spectrometry (LC-MS). This study evaluates N-alkylpyridinium sulfonates (NAPS) as versatile exogenous scouts for highly multiplexed stMRM.,The chromatographic and ionisation behaviours of NAPS were characterised across three stationary phases (reversed-phase C18, F5 and hydrophilic interaction liquid chromatography (HILIC)) in positive and negative electrospray ionisation. Due to their zwitterionic structure, NAPS ionised efficiently in both polarities, thereby simplifying dual-polarity acquisitions. Using NAPS as retention-time-independent triggers, we developed a comprehensive multi-mode assay monitoring 559 metabolites.,To validate this methodology, we investigated the physiological impact of silver (Ag) exposure on the digestive caeca of the sentinel amphipod Gammarus fossarum. Multivariate analysis revealed metabolic shifts. Mapping these alterations onto species-specific networks highlighted a pronounced disruption of the purine metabolism pathway, characterised by consistent downregulation of xanthine and related intermediate precursors.,In conclusion, NAPS are highly effective dual-polarity scout compounds that simplify the multiplexing of stMRM assays. This analytical strategy is a reliable tool for capturing complex molecular responses to environmental stressors in ecotoxicology.

Accurate identification of lipid isomers remains a major challenge in metabolomics, particularly for bile acids (BAs), whose biological functions critically depend on the number, position, and stereochemistry of hydroxyl groups as well as on the nature of their conjugation. Conventional tandem mass spectrometry (MS/MS) with collision-induced dissociation (CID) often fails to resolve isomeric lipids differing only in subtle structural features, leading to an underestimation of lipidome complexity. Here, we present an analytical framework integrating electron-activated dissociation (EAD) or ion mobility spectrometry (IM) with high-resolution liquid chromatography-mass spectrometry to improve annotation of BA isomers in untargeted metabolomics. EAD provides nonergodic fragmentation that preserves labile bonds and reveals site-specific details, while IM separates ions by their collision cross section (CCS), supplying orthogonal structural information. Using synthetic standards and human plasma extracts, we show that EAD-derived diagnostic ions markedly enhance structural discrimination and enable consistent and reproducible identification of BA isomers compared to CID-only workflows, while CCS measurements alone lack sufficient robustness to reliably distinguish closely related BA isomers across measurements. The integrated data set enables confident assignment of positional and conjugation variants, contributing to a more complete representation of BA diversity. This multidimensional approach offers a robust platform for structural lipidomics and supports the establishment of transferable spectral and mobility libraries to advance metabolome annotation accuracy.

En plus de leurs propriétés structurales comme constituants majeurs des membranes biologiques des cellules, les lipides jouent de nombreux rôles dans la signalisation cellulaire, le stockage d’énergie et le transport de protéines. Leurs importances biologiques ont mené à une augmentation accrue des méthodes analytiques pour la caractérisation d’espèces moléculaires uniques. De récents progrès en spectrométrie de masse ont amené à la caractérisation et à la quantification des espèces moléculaires des lipides dans des extraits lipidiques bruts (Han and Gross, 2005; Murphy et al., 2001). Par exemple, les espèces moléculaires de phospholipides peuvent être identifiées spécifiquement par leur tête polaire, la nature de leurs chaînes d’acide gras et leur positionnement au niveau du squelette glycérol.