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Inositol phosphates (InsPs) and inositol pyrophosphates (PP-InsPs) are key regulators of cellular signaling and metabolism, yet developmental changes in the InsP/PP-InsP network in eukaryotic systems remain poorly understood. Here, we combine isomer-resolved capillary electrophoresis-mass spectrometry (CE-MS) with genetic perturbations to characterize InsP metabolism during the Drosophila melanogaster development. Our analyses reveal extensive developmental reprogramming of the InsP pathway, with early developmental stages exhibiting broad lower-order isomer diversity that progressively narrows into a more restricted metabolic state enriched in Ins(1,3,4,5,6)P5, InsP6, and PP-InsPs at later stages. Metamorphosis is characterized by a marked increase in 5-PP-InsP5, which emerges as the predominant pyrophosphate species in adults. Perturbation of dedicated kinases suggests that this metabolic remodeling is essential for developmental progression. RNAi-mediated IPK2 depletion disrupts higher-order InsP synthesis by reducing InsP5 levels, and results in failed metamorphosis. IPK1 depletion delays development and induces pronounced isomer-selective redistribution within the InsP5 pool, indicating network-level changes beyond simple precursor accumulation. IP6K depletion specifically abolishes 5-PP-InsP5 production, impairs tissue morphogenesis during pupal stages, and causes rapid post-eclosion lethality. Unexpectedly, depletion of either IPK2 or IP6K leads to the presence of 2-PP-InsP5. Collectively, these findings establish the Drosophila melanogaster InsP pathway as a dynamically regulated developmental network, particularly rich in previously undescribed InsP isomers, in which stage-specific metabolic remodeling parallels metamorphosis, tissue maturation, and adult viability.

Capelin (Mallotus villosus), a key forage fish in the Northwest Atlantic, links zooplankton to predators including commercial fishes, seabirds, and marine mammals, yet its life-cycle movements in the Gulf of St. Lawrence (GSL) remain poorly understood. Between 2022 and 2024, otoliths from 927 individuals collected during and after spawning were analysed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Building on previous work on regional structuring, seven trace elements (Li, B, Mg, K, Zn, Sr, Ba) were used to discriminate three regions. Early-life regional signatures were inferred through an edge-to-core approach, assigning otolith core chemistry to one of these regions using quadratic discriminant analysis. The core was treated as an integrated early-life signal (late-larval to early juvenile period) rather than a strictly natal signature. Spatial variation in core chemistry was consistent across cohorts, mirroring the stability documented on the otolith edge. Results revealed widespread dispersal alongside partial regional residency: individuals with northeastern early-life signatures showed the strongest correspondence between early-life and capture regions, whereas other regions were more connected. Fish sampled during spawning were more often reassigned to their inferred early-life region than post-spawning fish, a regional-scale homing-like pattern consistent with regional spawning fidelity. This coexistence of dispersive and resident strategies likely generates a portfolio effect buffering the population against environmental variability and localised reproductive failures.

ABSTRACT Rationale Ametryn poses significant risks to aquatic ecosystems, but conventional MRM methods suffer from matrix interference and limited sensitivity. To overcome these limitations, we established a more selective and sensitive UHPLC-MS3 approach that effectively suppresses background noise and enhances signal-to-noise ratio, enabling reliable quantification of ametryn in zebrafish tissues. Methods A novel UHPLC-MS3 method with electrospray ionization was developed. Quantification employed the MS3 transition m/z 228.0 → 186.1 → 158.0. Five zebrafish tissues (liver, muscle, brain, intestine, gill) were analyzed following sample preparation. Fast chromatographic separation was achieved in 2.8 min. Results Compared with MRM, the MS3 method substantially reduced matrix interference, enhanced signal intensity from 6.4 × 104 to 1.6 × 107 cps, and increased the signal-to-noise ratio from 6.3 to 45. The assay exhibited excellent linearity (10–1000 pg/mL), and validation results for accuracy, precision, recovery, matrix effects, and stability all met FDA bioanalytical requirements. Conclusions This study presents the first application of UHPLC-MS3 for quantitative analysis of ametryn in multiple zebrafish tissues, providing a reliable high-throughput platform for residue monitoring and mechanistic toxicology research.

ABSTRACT Rationale Nitrilases are widely used as biocatalysts in pharmaceutical manufacturing because of their high stereoselectivity and mild reaction conditions. However, residual nitrilase in final drug products may compromise product quality and safety, highlighting the need for sensitive and reliable analytical methods for its monitoring and control. Methods In this study, a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for the determination of residual nitrilase in pharmaceutical formulations. Results Recombinant nitrilase expressed in Escherichia coli was purified by Ni2+ affinity chromatography and lyophilized prior to analysis. Following systematic optimization of digestion and chromatographic conditions, the method achieved a detection limit of 0.17 μg/g. The LC–MS/MS method was successfully applied to the analysis of brivaracetam samples at a concentration of 2000 μg/g, with residual nitrilase levels consistently below 85 μg/g, meeting relevant quality control requirements. Conclusions In this study, a sensitive and reliable LC–MS/MS method was developed for the determination of residual nitrilase in brivaracetam. The proposed method may serve as a general analytical strategy for quality control of nitrilase-related pharmaceutical products.

Constructing atomically coupled W–O–Ru interfacial units on RuO2 triggers a dynamic strain evolution during the oxygen evolution reaction. An initial tensile strain secures structural stability, while a self-adjusting transition to interfacial compression optimizes catalytic activity. This dynamic strain engineering effectively decouples the long-standing activity-stability trade-off, enabling highly efficient and durable acidic water oxidation. ABSTRACT Developing highly active and durable acidic oxygen evolution reaction (OER) electrocatalysts remains a central challenge for proton-exchange membrane water electrolysis (PEMWE). Here, we combine theory-guided design, atomic-layer engineering, and operando spectroscopy to create a structurally robust, mechanistically tuned Ru-based catalyst. Density functional theory reveals that depositing W1O3 onto RuO2 maximizes Ru and O vacancy formation energies, outperforming other tested transition metals. Guided by this, we employ atomic layer deposition to construct atomically coupled W–O–Ru interfacial units on RuO2 (W–O–RuO2), generating a tensile-stressed surface while preserving the rutile core. Comprehensive in situ spectroscopy and mass spectrometry demonstrate that this architecture effectively suppresses lattice–oxygen activation, shifting the reaction from a lattice–oxygen mechanism to a more reversible adsorbate evolution mechanism. Operando x-ray absorption spectroscopy confirms the dynamic stability of the W–O–Ru interface during OER, which evolves into a resilient, mildly compressive (1%) state without degrading. Consequently, W–O–RuO2 demands a mere 168 mV overpotential at 10 mA cm− 2 and sustains 1 A cm− 2 in a PEMWE device for 1000 h with an ultra-low degradation rate of 63.3 µV/h. This work establishes interfacial unit engineering as a generalizable blueprint for designing exceptionally stable acidic OER catalysts.