Search Results (7,278)

Nitrogen (N) availability strongly influences tea growth and the accumulation of quality-related metabolites, but long-term responses to withdrawal of external N can vary among cultivars. In this study, we characterized phenotypic, spectral, biochemical, and transcriptomic responses of four Camellia sinensis accessions—‘Kolkhida’, ‘Karatum’, and γ-irradiation-derived mutant forms #582 and #619—during two, four, or six months of complete withdrawal of exogenous NH₄NO₃ in greenhouse sand culture. Phenotypic, spectral, and biochemical measurements included all four accessions at all three time points; RNA-seq data were available for all four accessions were represented at four and six months, whereas two-month point were available only for ‘Kolkhida’ and ‘Karatum’. Nitrogen withdrawal decreased L-theanine and caffeine and generally increased simple and gallated catechins, consistent with a change in carbon/nitrogen balance towards phenolic metabolism. The four cultivars exhibited markedly distinct responses. ‘Karatum’ showed the optimum resilience, with minimal phenotypic alteration and a neutral transcriptional response, while #582 demonstrated a stronger stress-associated phenotype and metabolic response. Within the available RNA-seq comparisons, DEG counts were lower at four months than at six months, while the two-month datasets for ‘Kolkhida’ and ‘Karatum’ contained the largest DEG sets for those two cultivars, suggesting a phased acclimation process. CsELIP1, CsSRG1, CsHHO2/4, CsNRT2.4, and CsTAT2 were identified as potential candidate genes associated with nitrogen limitation, flavonoid regulation, and amino acid metabolism. Our findings show that N-deficiency reactions in tea are highly cultivar- and time-dependent, making single-time-point evaluations insufficient. We propose ‘Karatum’ as a promising candidate for further evaluation in low-nitrogen dose–response and field trials based on our combined biochemical and transcriptional findings. Full article

This study investigated the antibacterial activity and underlying mechanisms of essential oil extracted from Motuo citron against representative foodborne pathogens, including Staphylococcus aureus and Escherichia coli. The essential oil was obtained by steam distillation, and its chemical composition was analyzed by GC–MS. Limonene, γ-terpinene, and 3-carene were the predominant monoterpenes and may contribute substantially to the antibacterial activity. The Oxford cup assay confirmed strain-specific antibacterial effects. The essential oil showed stronger activity against S. aureus, with an inhibition zone of 22.29 ± 0.82 mm, a minimum inhibitory concentration (MIC) of 3.75 μL/mL, and a minimum bactericidal concentration (MBC) of 7.5 μL/mL. In contrast, its activity against E. coli was weaker, with an inhibition zone of 11.85 ± 0.49 mm, an MIC of 7.5 μL/mL, and an MBC of 15 μL/mL. Mechanistic analyses showed that the essential oil significantly reduced bacterial ATP levels and inhibited key enzymes involved in glycolysis and the tricarboxylic acid cycle, thereby impairing energy metabolism. It also disrupted bacterial cell wall and membrane integrity, resulting in cell rupture and cytoplasmic leakage. In addition, the essential oil disturbed core metabolic pathways, including amino acid biosynthesis, lysine biosynthesis, and tryptophan metabolism, causing severe metabolic imbalance in a dose-dependent manner. Motuo citron essential oil exerts antibacterial effects through the combined disruption of cell membranes, inhibition of energy metabolism, and interference with amino acid metabolism. As a natural plant-derived antibacterial agent, it shows potential for development as a food preservative and pharmaceutical antimicrobial. Full article

Acute kidney injury (AKI) is a common critical syndrome with high morbidity and mortality, and a subset of patients may progress to chronic kidney disease. Recent studies have revealed that gut microbiota and their metabolites play pivotal roles in the pathogenesis of AKI. Under AKI conditions, the gut microbiota composition undergoes significant alterations, characterized by decreased beneficial bacteria and expansion of opportunistic pathogens, accompanied by impaired intestinal barrier and disordered microbial metabolism. Gut microbiota metabolites can be classified into protective metabolites (short-chain fatty acids, secondary bile acids, tryptophan metabolites, D-amino acids, and polyamines) and toxic metabolites (indoxyl sulfate, p-cresyl sulfate, trimethylamine N-oxide, and endotoxin). The former exert renoprotective effects through anti-inflammatory, antioxidant, and barrier-maintaining mechanisms, while the latter aggravate kidney injury via oxidative stress, inflammation activation, and hemodynamic disturbance. Based on the gut–kidney axis theory, interventions targeting gut microbiota (probiotics, prebiotics, fecal microbiota transplantation) and those targeting metabolites (supplementation of protective metabolites, removal of toxic metabolites) have shown promising prospects. This narrative review summarizes the characteristics of gut microbiota changes, classification and function of key metabolites, core mechanisms driving AKI, and microbiota-based intervention strategies, aiming to provide novel insights for early recognition and precision prevention of AKI. Full article

Sulfur metabolism and stress responses are fundamental to plant growth and seed development. ETHE1 encodes a mitochondrial sulfur dioxygenase that plays important roles in these processes; however, its function in Jatropha curcas remains unknown. In this study, we report the cloning and in silico characterization of a putative JcETHE1 gene from J. curcas. Bioinformatic analysis revealed that JcETHE1 has an open reading frame of 726 bp encoding a 241-amino-acid protein, which is predicted to localize in mitochondria and possesses a typical sulfur dioxygenase conserved domain. Because the transcript ends were not experimentally confirmed and the predicted protein is shorter than related plant homologues, the possibility that the cloned sequence is partial cannot be excluded. Phylogenetic analysis showed that JcETHE1 clusters within the Euphorbiaceae clade, showing high similarity to ETHE1 from Manihot esculenta and Hevea brasiliensis. In silico promoter analysis suggested that, in addition to core elements, the JcETHE1 promoter contains multiple putative regulatory elements associated with light response, hormone responses (ABA, ethylene, gibberellin), floral development (CArG-box, AAGAA-motif), stress responses, and endosperm development. These findings provide a molecular basis for future functional studies of JcETHE1 and suggest that it may serve as a potential candidate gene for further investigation into reproductive development and stress responses in J. curcas. However, these hypotheses require experimental validation. Full article

Obesity is increasingly recognized as a complex metabolic disorder characterized by persistent redox imbalance, rather than merely excess body weight. Its pathophysiology extends beyond energy imbalance to encompass chronic redox disruption. Expansion of adipose tissue, particularly in visceral depots, exceeds mitochondrial capacity, impairs antioxidant defenses such as superoxide dismutase, catalase, and glutathione peroxidase, and perpetuates chronic low-grade inflammation via nuclear factor kappa B (NF-kB) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase pathways. This review synthesizes preclinical evidence for diverse interventions, including vitamins A, B, C, E, and D; minerals such as zinc and selenium; amino acids such as N-acetylcysteine (NAC), L-carnitine, and taurine; various antioxidant compounds; and approved drugs including metformin, exenatide, fenofibrate, and orlistat. Despite differing structures and mechanisms, these interventions converge on restoring redox balance by activating nuclear factor erythroid 2–related factor 2 (Nrf2)/AMP-activated protein kinase (AMPK), increasing glutathione, and stabilizing mitochondria. However, translation of these preclinical findings into clinical practice requires further clarification of dosing, delivery methods, and long-term safety. Full article

Auxin plays a positive role in plant responses to low-phosphorus stress. However, the molecular mechanisms underlying indole-3-acetic acid (IAA)-mediated responses to phosphorus deficiency in alfalfa remain poorly understood. Alfalfa (Medicago sativa L.) cultivar ‘Zhongmu No. 3’ was subjected to two treatments: normal phosphorus (NP, 1000 μM KH₂PO₄) and low phosphorus supplemented with 1 μM IAA (LP + IAA, 10 μM KH₂PO₄). Morphological traits, physiological parameters, transcriptomic profiles, and metabolite accumulation were analyzed at 48 h and 10 days following treatment. Compared with the NP group, plants in the LP + IAA group showed marked changes in growth-related traits. At 48 h, plant height increased by 34%, total root length was 1.24-fold that of the NP group, and lateral root number increased by 23.48%. After 10 days, root fresh weight increased by 28%, total root length was 1.25-fold that of the NP group, lateral root number increased by 36.58%, and root volume increased by 22.2%, whereas plant height, stem diameter, and shoot fresh weight remained comparable to those of the NP group. Root acid phosphatase activity was 114.8% higher than that of the NP group at 48 h. Transcriptome analysis identified 1274 and 2277 differentially expressed genes (DEGs) between the NP and LP + IAA groups at 48 h and 10 days, respectively. At 48 h, the up-regulated genes were amino phospholipid ATPase 9 and amino alcohol phosphotransferase 1, whereas phosphate transporter 1 and purple acid phosphatase 12 were up-regulated at 10 days. Metabolomic analysis identified 308 and 1296 differentially accumulated metabolites (DAMs) at 48 h and 10 days, respectively. Early responses were enriched in purine metabolism and involved (5′-phosphoribosyl)-5-formamido-4-imidazolecarboxamide (FAICAR), whereas prolonged treatment involved L-aspartic acid, adenine, and cAMP. Integrated analyses identified tryptophan metabolism, cysteine and methionine metabolism, glycerophospholipid metabolism, and plant hormone signal transduction as major regulatory pathways. CDP-choline accumulation and changes in lipid-remodeling genes further indicated enhanced membrane phospholipid remodeling. Overall, these results provide insight into the morphological, physiological, transcriptional, and metabolic responses of alfalfa to low phosphorus in the presence of exogenous IAA. Full article

Bemisia tabaci is a globally important crop pest and virus vector with widespread resistance to conventional insecticides. We evaluated the insecticidal activity of a soybean-derived lecithin preparation and associated physiological responses. Leaf-surface, dried-residue contact, artificial-diet, and egg bioassays were combined with RNA sequencing, untargeted metabolomics, RT-qPCR, histology, and transmission electron microscopy. Dried-residue exposure yielded a 4 h LC₅₀ of 1.16 mg mL⁻¹ (95% confidence interval, 0.948–1.403 mg mL⁻¹), whereas 10 mg mL⁻¹ lecithin caused 100% adult mortality within 4 h and reduced egg hatchability from 99.44% to 37.78%. No mortality was detected after adults were provided with a sucrose diet containing 10 mg mL⁻¹ lecithin for 24 h. Exposure at the 4 h LC₅₀ was associated with differential expression of 135 genes and changes in 599 metabolic features, including responses related to cuticle organization, lysosomal and autophagy pathways, and amino acid metabolism. Histology and transmission electron microscopy revealed altered abdominal tissue organization and cellular ultrastructure. These findings establish contact-associated and egg-stage activity of lecithin against B. tabaci under laboratory conditions and identify accompanying structural, transcriptional, and metabolic responses. The molecular events responsible for mortality and the contribution of ingestion-mediated exposure remain unresolved. Full article

Beer flavor depends on the composition and structural characteristics of fermentable carbohydrates generated during mashing. Although mashing strategy is known to influence wort composition, the mechanistic relationship between mashing-induced variations in carbohydrate structure and subsequent yeast metabolism and flavor formation remains poorly understood. This study aimed to compare the effects of two mashing procedures, infusion mashing (IMM) and decoction mashing (DMM), on carbohydrate structure, fermentation behavior, and flavor attributes of wheat beer. The physicochemical properties were analyzed using standard methods; organic acids, amino acids, and volatile compounds were analyzed using chromatographic techniques combined with multivariate analysis. Instrumental aroma and taste characteristics were further assessed using electronic nose and electronic tongue systems. Compared with IMM, DMM wort contained numerically higher proportions of low-degree-of-polymerization carbohydrates and higher amino acid concentrations. These compositional differences were associated with divergent fermentation kinetics and distinct volatile and nonvolatile metabolite profiles in the finished beers. DMM was associated with higher concentrations of medium-chain fatty acid ethyl esters, whereas IMM was associated with higher concentrations of acetate esters, higher alcohols, and aldehydes, consistent with faster fermentation and enhanced amino acid catabolism. Multivariate analysis confirmed differentiation in volatile profiles and instrumental aroma characteristics between the two beers. Together, these results suggest an association of mashing strategy with variations in carbohydrate structure, fermentation behavior, and volatile compound profiles in wheat beer. These findings offer a framework for the process-level control of beer flavor. Full article

Microorganisms are the core drivers of ripened Pu-erh tea (RpPT) quality formation. However, the mechanisms of the microbiological and flavor chemical changes during the fermentation process remain unclear, which limits the quality control of ripened Pu-erh tea fermentation. A physicochemical analysis revealed that fermentation significantly reduced the contents of water extracts, tea polyphenols, free amino acids, soluble sugars, and most catechins (p < 0.05), while flavonoids and tea pigments were significantly accumulated. Amplicon sequencing revealed that Pantoea and Bacillus were the dominant bacterial genera during the early and late fermentation stages, with maximum relative abundances of 97.89% and 63.66%, respectively. Aspergillus and Thermomyces were the dominant fungal genera, reaching maximum relative abundances of 98.34% and 62.59%, respectively. During fermentation, bacterial diversity initially increased and then declined, whereas fungal diversity dropped sharply and subsequently stabilized. Co-occurrence network analysis indicated that microbial interactions were primarily cooperative, with network complexity gradually diminishing as fermentation progressed. Functional prediction showed enhanced microbial metabolism of amino acids and carbohydrates during the mid-to-late stages. Crucially, the stage-specific microbial communities were significantly correlated with distinct flavor compounds, shaping the final aroma profile of ripened Pu-erh tea. These dynamics explain the variations in tea quality and provide critical insights for optimizing the fermentation process. Full article

Background/Objectives: Protein supplementation may elevate advanced glycation end products (AGEs) through higher dietary AGE (dAGE) content and increase amino acid-driven endogenous formation. Protein supplementation from different sources may differentially affect AGE levels, possibly through differences in amino acid composition, digestion and metabolism, but evidence from randomized controlled trials (RCTs) remains limited. This study aimed to examine the effect of protein supplementation from either casein (animal-based) or soy (plant-based) protein isolates on circulating, skin, and dAGE levels in older adults following a healthy dietary pattern (HDP). Methods: In this 16-week RCT, 55 older adults (mean age: 66 years old) in Singapore were assigned either to control (no supplementation), casein protein isolate supplementation, or soy protein isolate supplementation. This study was registered at clinicaltrials.gov as NCT05400005. Results and Discussion: Overall, there were no alterations in dietary, skin and total circulating AGE levels after protein supplementation when adhering to an HDP such as My Healthy Plate (MHP). However, different sources of protein supplementation resulted in differential changes in specific plasma AGE markers. Two-way ANOVA analysis showed that soy protein supplementation led to a significant increase in plasma N(6)-(1-carboxymethyl)-L-lysine (CML) compared to the other groups (week 0: 0.72 ± 0.10, week 16: 0.80 ± 0.10, p_int = 0.040), while a paired t-test showed that casein protein supplementation led to a significant within-group increase in plasma pentosidine (week 0: 0.77 ± 0.06, week 16: 0.80 ± 0.05, p-value = 0.045). Other AGEs showed no significant changes. Conclusions: Protein supplementation while adhering to MHP did not significantly influence overall circulating and skin AGEs in older adults in Singapore. A differential response was observed only for plasma CML levels with soy protein supplementation, whereas the within-group increase in plasma pentosidine following casein supplementation should be interpreted with caution and requires further investigation. Full article

Free amino acids serve as a crucial hub connecting plant life activities with human nutrition. The fruits of Cucurbitaceae crops are natural nitrogen reservoirs, rich in free amino acids such as citrulline, arginine, and γ-aminobutyric acid (GABA). To investigate the spatial accumulation characteristics and differential distribution of free amino acids in cucurbit fruits, this study measured the contents of 19 free amino acids in the fruit stem, epicarp, endocarp, pulp, and seeds of 10 cucurbit species (12 varieties) at the mature stage. The results revealed that free amino acid accumulation exhibits significant tissue specificity and species specificity, forming diverse nitrogen metabolism hubs. Glutamine, aspartate, asparagine, arginine, and citrulline constitute a highly coordinated core module of nitrogen metabolism in Cucurbitaceae. Methionine, valine, and some other amino acids were consistently present at extremely low levels across tissues, indicating a competitive diversion of conserved metabolic pathways coexisting among species. Species classification based on free amino acids differed markedly from traditional taxonomy based on gene domestication, implying environmental selection pressures and non-linear gene-metabolite network relationships. Glutamine, GABA, citrulline, and arginine were identified as core hub metabolites supporting tissue type classification. This study revealed the allocation characteristics of free amino acids in fruits of various cucurbit crops and established a functional model integrating nitrogen assimilation, flavor/energy metabolism, stress tolerance/defense signaling, and storage across different tissue types of multiple cucurbit crops, providing new perspectives for precision breeding and domestication mechanism research in Cucurbitaceae. Full article

Ehretia macrophylla fruit is a traditionally used but underutilized functional resource that is noted for its diverse phytochemical composition, which includes flavonoids and polyphenols. However, the systematic metabolic transformations that occur in the fruit during post-harvest storage—particularly those associated with its traditional processing into dark fruit tea—remain largely unknown, limiting efforts to optimize quality and processing strategies. In the study, to address this gap, we employed a widely targeted metabolomics approach based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) to dynamically profile the fruit metabolome across four storage stages (T0, T4, T8, T12). A total of 1101 metabolites were putatively annotated, and day 8 (T8) emerged as a potential pronounced metabolic inflection point. From T8 onward, 30–40% of metabolites showed differential accumulation, characterized by a gradual rise in nutrition-relevant lipids, amino acids, and vitamins. In contrast, key antioxidant-related metabolites, including phenolics and flavonoids, increased transiently before T8 but declined sharply thereafter. These coordinated shifts correlated with an increased representation of lipid- and alkaloid-related metabolic pathways, whereas flavonoid-associated features showed a relative decline. Collectively, these findings provide insights into the biochemical processes potentially associated with fruit blackening and the marked decline in antioxidant capacity during traditional processing. Our study provides the first metabolic blueprint connecting traditional processing practices with phased metabolic remodeling, offering a scientific foundation for quality assessment and the development of informed post-harvest strategies for processing E. macrophylla fruit. Full article

Ammonia nitrogen represents a critical environmental stressor in aquaculture and exerts adverse impacts on the growth, reproduction and survival of shellfish. In the present study, diploid Pacific oysters (Magallana gigas) were exposed to ammonia nitrogen stress for 0, 6, and 48 h. We combined histopathological examination, antioxidant enzyme measurements, transcriptome profiling, and metabolome profiling to characterize time-dependent hepatopancreatic responses. Tissue injury became progressively more severe with prolonged exposure. Superoxide dismutase activity increased throughout the experiment, whereas catalase and glutathione peroxidase activities and malondialdehyde content showed an increase followed by a decrease, with no statistically significant differences in malondialdehyde content among the three time points. Transcriptome data revealed alterations in genes associated with ATP-binding cassette transporters, lysosomal function, endocytosis, and autophagy. Metabolic alterations were mainly associated with nucleotide, purine, pyrimidine, and sphingolipid metabolism. Cross-omics integration linked these molecular shifts to transmembrane transport, glutathione metabolism, sulfur-containing amino acid metabolism, and amino acid biosynthesis. The consistency between transcriptomic and metabolomic signals further highlights the central roles of transport processes, antioxidant defense, and metabolic adjustment under ammonia nitrogen exposure. These findings indicate that diploid Pacific oysters respond to ammonia nitrogen stress through coordinated regulation of oxidative stress responses, transmembrane transport, intracellular degradation and clearance, and metabolic reorganization. These findings provide insights into the adaptive mechanisms of bivalves exposed to ammonia nitrogen stress. Full article

Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in lignin monomer biosynthesis and is crucial for plant cell-wall lignification. However, the CAD gene family and its role in watermelon rind lignification are poorly understood. In this study, we performed genome-wide bioinformatics analysis to identify the CAD gene family in watermelon. We identified predicted gene expression in two contrasting cultivars [WRH (hard rind, high lignin) and WRS (soft rind, low lignin)]. A total of seven CAD-like genes (ClCAD1–ClCAD7) were identified on three chromosomes (1, 2, and 5), all encoding full- or near-full-length proteins with CAD-related domains. Genomic collinearity revealed one segmental duplication (ClCAD3–ClCAD4) in watermelon; however, the comparative genomes of Arabidopsis and melon identified five and eight homologous gene pairs, respectively. Phylogenetic analysis indicated that ClCAD-like genes are more closely related to melon than to Arabidopsis. ClCAD3 and ClCAD4 proteins were grouped with AtCAD4 and AtCAD5 from Arabidopsis, which are important for lignin biosynthesis. Promoter analysis predicted elements responsive to jasmonic acid, abscisic acid, cytokinin, light, and stress. Subcellular localization analysis in the epidermal cells of Nicotiana benthamiana leaves was consistent with a cytosolic distribution for ClCAD3. STRING analysis predicted functional associations of ClCAD3 with proteins involved in aldehyde metabolism, branched-chain amino acid biosynthesis, and basal carbon metabolism, including ClALDH1/2, ClALS, Cl2HACL, and ClKBA1. qRT-PCR analysis of roots, stems, leaves, and fruit rind (21 days after pollination, DAP), as well as rind at 1, 14, and 28 DAP, indicated that ClCAD3, ClALS, and ClALDH2 are expressed at higher levels in WRH than in WRS. ClCAD3 transcript abundance in roots, leaves, and fruit rind was consistently higher in WRH. Together, these findings clarify the evolutionary features and organ-level expression of the CAD-like gene family in watermelon and identify ClCAD3 as a candidate gene associated with lignin biosynthesis. The results provide genetic insights into candidate genes potentially involved in lignification-associated rind hardness and a theoretical foundation for improving rind texture in watermelon fruit through modern molecular breeding approaches. Full article