Search Results (2,395)

Colorectal cancer (CRC) is the third most common malignancy worldwide. Detailed characterization of cell surface proteins (CSPs) is essential for the identification of prognostic biomarkers and the development of novel therapeutic strategies. Cancer progression and epithelial cell polarity influence the expression levels and subcellular localization of these proteins. However, quantitative information on the distribution of CSPs between the apical and basolateral membranes remains limited, particularly in CRC cells. Here, we developed a rapid, high-throughput method based on the enrichment of biotinylated peptides and proteins from the apical and basolateral surfaces of polarized CRC epithelial cells (HT29 and HCT116), followed by LC-MS/MS analysis. This approach enables the simultaneous identification of the side-specific distribution of ~1200 CSPs. In addition, almost 500 potential N-glycosylation sites with the canonical consensus sequence of these proteins were identified, which may serve as targets for future site-specific glycosylation analyses. To evaluate the sensitivity of the method, we altered the surface proteome by generating TKS4-knockout cells and identified several surface markers whose expression levels differed significantly from those of wild-type cells. Overall, our findings provide new insights into the role of CSPs in CRC cells and gene-edited models, particularly in the context of TKS4-dependent epithelial-to-mesenchymal transition (EMT)-like phenotypes that model cancer metastasis. Full article

While withering is a critical processing step influencing the flavor profile of white teas, the effects of temperature-changing withering remain elusive. This study systematically investigated the variations in two withering methods (natural withering, temperature-changing withering) in volatile compounds of white teas made from four cultivars. The quality of white teas produced from ‘Mingshan No. 131’ (MS131), ‘Fuxuan No. 9’ (FX9), ‘Ziyan’ (ZY), and ‘Fudingdabai’ (FDDB) was evaluated using quantitative descriptive analysis (QDA), headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), and odor activity value (OAV) analysis. The sensory evaluation results indicated that temperature-changing withering enhanced the development of sweet and fruity aromas while suppressing grassy notes. A total of 176 volatile compounds were identified, and temperature-changing withering induced significant alterations in the aroma profile, notably increasing the levels of ketones, esters, and alkenes (p < 0.05). Based on the criteria of OAV > 1, p < 0.05, and a fold change ≥ 1.5 (for upregulated compounds) or ≤0.67 (for down-regulated compounds), key volatile compounds in white teas from the four cultivars were identified. The common upregulated volatile compounds, namely 1-octen-3-one, cedrol, (E,E)-2,4-heptadienal, and (E)-2-hexenal, promoted the fresh flavor profile of white teas. These findings demonstrate that temperature-changing withering optimizes flavor-related metabolites, thereby providing a theoretical foundation for improving white tea processing. Full article

Background: The rapid expansion of functional ready-to-drink (RTD) beverages—formulated with prebiotic fibers, botanical extracts, and reduced sugar—has outpaced systematic characterization of their small-molecule composition. Methods: We applied dual-mode untargeted high-resolution liquid chromatography–tandem mass spectrometry (LC–MS/MS), integrating hydrophilic interaction (HILIC) and reversed-phase C18 separations, to profile five commercial RTD beverages spanning distinct formulation categories: Coca-Cola^®, Poppi^® Orange, OLIPOP^® Cream Soda, Pure Leaf^® Unsweetened Black Tea, and BeePop™ Peach + Orange Blossom Honey. Results: Across all products, 478 compounds were structurally annotated at Metabolomics Standards Initiative (MSI) Levels 1 and 2, of which 42 matched compounds with reported bioactivity in a curated literature-based reference database. Seventeen compounds—including the NAD+ precursor trigonelline and multiple B vitamins—were detected across all five products. The number and diversity of compounds with reported bioactivity varied substantially by product and correlated with botanical ingredient complexity. Conclusions: This work presents a qualitative molecular survey of the RTD beverage category using standardized, dual-mode untargeted metabolomics, providing a reference dataset for future targeted quantitation studies. Full article

Polymeric procyanidins (PPCs) constitute the major fraction of procyanidins, but they have poor bioactivity. The purpose of this study is to clarify the composition and content of PPCs from Vitis amurensis Rupr. (Vitaceae) seeds before and after depolymerization, thereby providing a theoretical basis for activity evaluation and application of proanthocyanidins (PCs). PPCs extracted from V. amurensis seeds were depolymerized by catechin-assisted sulfitation. The compositions and contents of PCs before and after depolymerization were qualitatively and quantitatively analyzed by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS), high-performance liquid chromatography (HPLC), and liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results showed that twenty-eight components were identified (7 monomers, 13 dimers, 5 trimers, 1 tetramer and 2 unknowns). Before depolymerization, tetrameric and higher polymers dominated, accounting for 58.81% of the relative content. After depolymerization, these high-molecular-weight compounds declined to <1% or became undetectable, while monomers and dimers (with minor trimers) surged to 42.89%. Among them, the relative content of two monomers and three dimers, catechin, epicatechin gallate and procyanidin B1–B3, increased by 37.00, 3.75, 10.98, 3.72 and 9.74 times, respectively. In conclusion, the method utilizing catechin-assisted sulfitation effectively depolymerizes PPCs from V. amurensis seeds into oligomeric components such as monomers and dimers. Full article

Background: Interpretation of pesticide residues in fruits requires tight integration of surveillance evidence, analytical capability, regulatory context, and mitigation data. Methods: This critical integrative review synthesises analytical chemistry, cumulative risk assessment (CRA), regulatory divergence, and mitigation evidence, strengthened by quantitative monitoring summaries and auditable regulatory examples. Routine enforcement continues to rely on validated QuEChERS extraction coupled with targeted LC-MS/MS and GC-MS/MS. High-resolution mass spectrometry (HRMS) adds unique value for metabolites, transformation products (TPs), and incident response, but its routine enforcement role remains constrained by confirmation logic and harmonised validation. Results: Monitoring shows that exposure is typically multi-residue rather than single-compound; the key interpretive challenge therefore shifts toward CRA prioritisation, sensitive-subpopulation assumptions, and transparent distinction between compliance signals and toxicological inference. We provide (i) headline compliance metrics from EU and US programmes, (ii) surveillance-derived high-frequency residue patterns and co-occurrence motifs to guide CRA prioritisation, (iii) an illustrative, traceable comparison of EU/US/Codex MRL divergence for emblematic citrus residues with EU evidence extracts and US/Codex traceability records, and (iv) mitigation evidence statements standardised by study type and transformation-product reporting. Conclusions: Pesticide residues in fruits should be interpreted through a risk-based framework that distinguishes compliance findings from toxicological concern, prioritises relevant multi-residue drivers, and evaluates mitigation according to both residue reduction and transformation-product uncertainty. Full article

Essential oils from aromatic plants are gaining traction as naturally derived preservative and antioxidant ingredients, yet the quantitative relationships between field climate conditions and both oil yield and food relevant bioactivity remain poorly characterised. Here, we characterised the leaf essential oil of Melaleuca bracteata F. Muell. “Revolution Gold” across a complete annual cycle using a fixed plant, multiscale spatio temporal sampling framework. Leaf samples were collected at four seasonal time points (March, June, September, and December) and four diurnal time points (06:00, 12:00, 16:00, and 21:00) from a single field individual in Meizhou, Guangdong, China. Gas chromatography–mass spectrometry (GC-MS) profiling identified 51 volatile constituents, with methyl eugenol dominating the composition (up to 93.67% in summer). Oil yield peaked in summer (2.43 mL kg⁻¹ dry weight) and was lowest in spring (1.28 mL kg⁻¹ dry weight). DPPH radical scavenging and ABTS radical cation decolorisation assays revealed that antioxidant activity was highest in summer harvested oils, with IC₅₀ values of 7.68 mg mL⁻¹ (DPPH) and 8.85 mg mL⁻¹ (ABTS), consistent with peak methyl eugenol accumulation. Permutation-based multiple regression (999 permutations; R² = 0.947) identified seasonal precipitation as the strongest positive predictor of oil yield (β = 11.22, p < 0.05), while temperature exerted a significant negative influence (β = −11.21, p < 0.05). Non-metric multidimensional scaling (NMDS) and permutational multivariate analysis of variance (PERMANOVA) confirmed highly significant seasonal clustering of compositional profiles (F = 15.258, p = 0.001) against negligible diurnal structuring (F = 0.178, p =0.991). Redundancy analysis (RDA) attributed 71.03% of total compositional variance to the climatic predictor set. Pearson correlation analysis established significant positive associations between methyl eugenol content and antioxidant capacity (r > 0.80, p < 0.05). These findings provide an integrated, climate resolved basis for harvest timing optimisation of M. bracteata and identify summer as the strategically optimal harvest window for yield and bioactive functionality. Full article

Despite the vast biodiversity of Mexican vipers, venom of endemic species has been barely studied. Here we analyzed the venom composition of three endemic species of rattlesnakes: Crotalus aquilus, C. triseriatus, and C. ravus. We used quantitative chromato-mass-spectrometry and compared venoms with C. molossus, a species commonly found in North America, in a comparative and phylogenetic framework. In total, we identified 165 proteins grouped in 19 main protein families, consistent with previous reports for viperid venoms. In C. aquilus and C. triseriatus, the most predominant protein-family type was Serine Proteases, and in C. triseriatus and C. molossus it was Snake Venom Metalloproteases. The Label-free quantification revealed a high proportion of Snake Venom Metalloproteases in C. aquilus, C. triseriatus, and C. molossus, reaching 28–47% of the total venom. In contrast, in C. ravus 47% of the venom was composed of Phospholipases A₂. Among the four species analyzed, C. triseriatus and C. aquilus were most similar in compositional profiles and their profiles are highly correlated. Venom composition in terminal clades and taxa were better explained by protein losses than evolution of new proteins. The triseriatus group share seven proteins, while the clade C. aquilus + C. triseriatus share seven derived protein features, of which six are protein losses. Full article

Aconitum poisoning is a major public health concern in East Asia, and remains difficult to diagnose when the causative toxins are not covered by routine targeted assays. In a poisoning incident that occurred in 2018, 15 individuals were affected, including five fatalities, after accidentally consuming a medicinal tincture during a shared meal. The comprehensive alkaloid profile of the tincture implicated in the poisoning was achieved through the integration of targeted analysis, molecular networking, and untargeted screening based on ultra-high performance liquid chromatography coupled to time-of-flight mass spectrometry, aiming to clarify the causative agents. Targeted quantitative analysis detected nine alkaloids derived from Aconitum plants, confirming the presence of Aconitum ingredients in the medicinal tincture. However, these alkaloids were either present at low concentrations or exhibited low toxicity, and thus were not the principal causative agents of this poisoning incident. Molecular networking revealed additional hidden diester-diterpenoid alkaloids (DDAs) and monoester-diterpenoid alkaloids (MDAs) that were undetected by targeted analysis. Untargeted screening identified 58 Aconitum alkaloids, including 15 DDAs, 17 MDAs, 17 amino-diterpenoid alkaloids (ADAs), 2 C20-diterpenoid alkaloids, and seven unclassified alkaloids. The three most abundant alkaloids were structurally identified as pseudoaconitine, 8-deacetylpseudoaconitine, and 3′-methoxyacoforestinine, and were identified as the main causative agents of this poisoning. To our knowledge, this is the first detection of these alkaloids in Aconitum poisoning in China. These findings demonstrate that integrated targeted and untargeted toxicological analysis can identify undocumented toxins in poisoning events of unknown origin and clarify the chemical etiology of unusual Aconitum poisoning. Full article

The complex lipid composition of Mycobacterium tuberculosis (MTB) plays a pivotal role in pathogenesis, immune evasion, and antimicrobial resistance. The continued surge in drug-resistant strains underscores the need for a deeper understanding of the molecular architecture underlying MTB pathogenesis and drug resistance. In this study, a comparative lipidomics approach was applied to explore the resistance-associated lipid alterations in drug-sensitive (DS), drug-resistant (DR), multidrug-resistant (MDR), and pre-extensively drug-resistant (PXDR) MTB clinical isolates. Lipids derived from whole bacilli (TL) and cell wall (CWL) extracts were separately analyzed using untargeted and targeted lipidomics approaches. Untargeted analysis revealed the abundance of fatty acyls, glycerolipids, glycerophospholipids, prenol lipids, polyketides, and saccharolipids, with distinct phenotypes and compartment-specific distributions. Notably, CWL extracts showed clearer resistance-associated separations relative to TL extracts. Targeted profiling further demonstrated enrichment of glycerolipids and PC and LPC lipids among drug-resistant isolates. Biomarker analysis identified discriminative lipid species in both extracts, albeit with greater discriminatory power in CWL. Overall, these findings elucidate coordinated and compartment-associated lipid alterations at the species level in different MTB clinical isolates. This will help to provide a valuable source for screening diagnostic biosignatures and intersecting biosynthetic pathways of mycobacterial lipids in the evolution of drug resistance in MTB for therapeutic interventions. Full article

Buds are a critical stage in the annual growth–dormancy cycle of perennial woody plants and are essential for survival and biomass accumulation. To safeguard these structures, trees employ both physical and chemical protection. Although Populus buds are known to contain rich phytochemistry, population-level variation remains largely unexplored. Here, we characterized bud phytochemistry across a population of Populus trichocarpa natural variants using gas chromatography–mass spectrometry and examined the antifungal properties of bud extracts. In the reference genotype Nisqually-1, a total of 32 lipophilic metabolites were detected, belonging to four chemical groups: terpenoids, phenylpropanoids, linear hydrocarbons, and others. Analysis of 49 additional P. trichocarpa natural variants revealed both shared features and substantial variation. All lines contained metabolites from the phenylpropanoid, linear hydrocarbon and terpenoid classes, which consistently dominated the profiles. However, quantitative differences in individual metabolites and relative class abundances distinguished the lines, allowing them to be grouped into three chemotypic clusters. To assess potential biological implications of phytochemical variance, we tested antifungal activity of bud extracts against the pathogenic fungus Fusarium oxysporum. Extracts from all 50 lines significantly inhibited fungal growth compared with controls. Correlation analyses between metabolite abundance and inhibition strength identified candidate metabolites that were most strongly associated with antifungal activity. Together, these findings reveal both conserved and variable components of bud phytochemistry in P. trichocarpa. The observed chemical diversity and consistent antifungal effects suggest that bud metabolites contribute to defense and may reflect adaptation across natural populations. Full article

Concerns about human exposure to micro- and nanoplastics (MNPLs), particularly nanoplastics (NPLs), have intensified in recent years. Consequently, there is a growing need for validated quantitative analytical methods capable of assessing NPLs in complex human biological matrices. Current approaches for NPL analysis are still limited by the absence of standardised protocols, difficulties in avoiding background contamination, and challenges associated with the selective identification and quantification of polymer-specific nanoparticles. Moreover, most common approaches for quantification by particle counting cannot be applied for NPLs < 500 nm. In this study, we developed and validated an analytical method for the detection and quantification of NPLs in human faeces. As an initial step, polyethylene (PE) and polypropylene (PP) nanoparticles (NPs) were synthesised using bottom-up methods and characterised by dynamic light scattering (DLS) and electron microscopy (SEM and TEM). To optimise and assess the extraction, synthetic faeces were prepared and used in spiking experiments to avoid background contamination from plastics. Two digestion strategies were evaluated: (i) Fenton’s reagent followed by strong acid digestion, and (ii) alkaline digestion. Quantitative determination of polymer-specific NPLs was performed by size-exclusion liquid chromatography coupled with high-resolution mass spectrometry and atmospheric-pressure photoionization (SEC-APPI-HRMS). Polymer identification was based on characteristic monomer-loss patterns and Kendrick Mass Defect analysis. Fenton-based digestion showed superior performance, yielding recoveries about 55–66% for PE and 59–61% for PP. The validated method achieved limits of detection and quantification of 0.015 and 0.058 μg/kg for PE, and 0.025 and 0.083 μg/kg for PP, respectively. Precision, expressed as %RSD, was 10.1% for PE and 20.1% for PP. These results demonstrate that SEC-APPI-HRMS combined with Fenton-based digestion provides a sensitive and reliable approach for the quantification of polymer-specific NPLs in human faeces. The method represents an important advance for human biomonitoring studies and supports future research aimed at assessing human exposure and the potential health risks associated with nanoplastics. Full article

Storage duration critically shapes the characteristic sweet and mellow quality of ripened pu-erh tea (RPT), yet the underlying chemical mechanisms remain poorly understood. This study investigated the sensory and chemical evolution of a representative commercial RPT product across a nine-year storage gradient (1, 3, 5, 7, and 9 years) by integrating Quantitative Descriptive Analysis (QDA), chromaticity measurement, targeted quantification of 42 non-volatile components, and Headspace Gas Chromatography–Mass Spectrometry (HS-GC-MS) volatilomics with multivariate statistical modeling. Prolonged storage drove systematic sensory maturation: the stale aroma gradually purified, and the taste profile transitioned significantly from heavy and mellow to sweet and mellow (p < 0.05), accompanied by a deepening infusion color with increased redness and yellowness indices. Targeted chemical profiling revealed significant decreases in total polyphenols and astringent esterified catechins, particularly epicatechin gallate (ECG) and epigallocatechin gallate (EGCG) (p < 0.05), while theabrownins remained stable and soluble sugars peaked at intermediate storage stages. Pearson correlation analysis linked these chemical shifts to sensory perception, with enhanced sweetness, mouthfeel thickness strongly associated with reduced monomeric catechins and free amino acids (p < 0.001). Volatilomics combined with K-means clustering and relative odor activity value (ROAV) analysis revealed a dual mechanism of flavor refinement: progressive accumulation and increasing odor activity of aged aroma markers (1,2,3-trimethoxybenzene, β-ionone) coupled with systematic attenuation of pungent acids and grassy aldehydes. These findings, based on a single, standardized commercial product, elucidate the chemical-sensory foundation of the sweet and mellow profile in aged RPT and provide candidate markers and a transferable analytical framework for quality assessment of stored teas. Full article

Saccharomyces cerevisiae (SC), an important unicellular yeast species in the biotechnology, beverage, and food industries, has remarkable applications in ethanol production. Lipids in SC play a crucial role in stress management during the fermentation process. Despite the importance of SC yeasts, comprehensive lipid profiling across multiple yeast strains remains limited. This study aimed to elucidate the comprehensive lipidomic profiles of 48 wine yeast strains of the SC species using a nontargeted liquid chromatography–mass spectrometry approach. A total of 135 lipid species were identified, representing five major lipid categories. Among the SC strains, strain 19 contained the highest relative concentrations of α-linolenic acid (ω-3) and linoleic acid (ω-6). Levels of polyunsaturated fatty acids were 4.6-fold higher in SC46 compared to SC13, suggesting strain-specific variations. Glycerolipids were the most abundant lipid components, with triacylglycerols showing the highest relative abundance in SC10, SC41, and SC48. These findings should be interpreted in light of the semi-quantitative nature of the dataset. Interestingly, bioactive lipids, such as N-acyl lysophosphatidylethanolamines, were putatively identified and structurally characterized using high-resolution mass spectra and MS/MS fragmentation patterns. This study provides insight into strain-specific differences in the yeast lipidome and may help improve our understanding of fermentation kinetics and industrial wine quality. Full article

N-glycosylation, particularly terminal mannose exposure, is a critical quality attribute affecting macrophage targeting and the clinical efficacy of enzyme replacement therapy for Gaucher disease. This study developed a universal, sensitive, and quantitative method to compare the N-glycan profiles of three recombinant human glucocerebrosidase products from different expression systems: imiglucerase, velaglucerase alfa, and velaglucerase beta. Using 2-aminobenzamide labeling combined with HILIC-UPLC-FLD and high-resolution mass spectrometry, an N-glycan profiling platform was established. A multidimensional calibration system integrating retention time, glucose unit values, and mass-to-charge ratios was constructed, and collision-induced dissociation tandem MS was used to identify isomers and phosphorylated glycans. The method showed good specificity, linearity, precision, and accuracy. Glycan profiling revealed clear product-dependent differences: imiglucerase was enriched in core-fucosylated Man3 structures, velaglucerase alfa was dominated by Man9 and contained more phosphorylated and sialylated glycans, whereas velaglucerase beta showed a highly homogeneous Man5 profile. These findings demonstrate how distinct manufacturing strategies shape glycosylation patterns and provide a basis for biosimilar development and comparability assessment. Full article