Search Results (1,121)

Largemouth bass (Micropterus salmoides) is a major aquaculture species in China. Facility-based aquaculture, such as the “168” model, a high-efficiency recirculating system using funnel-shaped ponds, has promoted water conservation and improved aquaculture efficiency through structural innovation. However, fish die sporadically as the stocking density increases with increasing fish growth. To address this issue, three density groups were established, namely, low (2.5 ± 0.5 kg/m³), medium (4.0 ± 0.5 kg/m³), and high (7.5 ± 0.5 kg/m³). Histological examinations, biochemical assays, and transcriptomic and metabolomic analyses of liver tissues were performed, and fish health was comprehensively evaluated. Histopathological analysis revealed that progressive hepatic vacuolization and severe tissue damage occurred as the fish density increased. Biochemical indicators revealed that the immune system and growth underwent compensatory activation at medium density, shifting to immune suppression, growth impairment, and hepatic exhaustion at high density. Integrated omics analysis revealed that under medium-density stress, the urea cycle was impaired; under high-density stress, Ser metabolism in the liver was rerouted, potentially to overcome methyl donor depletion and prevent disorders of polyamine metabolism, accompanied by a gradual transition from compensatory activation to functional exhaustion. These findings improve our understanding of the physiological response mechanisms of fish to high-density stress. This study provides a theoretical basis for optimizing high-density aquaculture technologies such as the “168” model. Full article

Polyamines such as putrescine, spermidine, and spermine play essential roles in most living organisms. They regulate fundamental processes, like cell proliferation, differentiation, growth, gene expression (DNA/RNA stability, transcription, and translation), and signal transduction. As important regulators, polyamines influence development, stress responses, and the progression of health and disease, including cancer and aging. These positively charged molecules have been extensively studied for decades. In humans, polyamines are often researched as potential therapeutic targets for diseases such as malaria and, more recently, COVID-19. Obligate parasites, such as Plasmodium falciparum, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), rely on host cellular machinery for survival, replication, and growth. Notably, both hosts and pathogens need polyamines to sustain these processes. This review summarizes current advances in understanding the roles of polyamines in humans, viruses, and obligate parasites. It also explores strategies to prevent pathogens from hijacking host polyamine metabolism as a way toward developing novel therapeutic interventions. Full article

The adoption of sustainable agricultural practices is essential to cope with climate change and to ensure soil health, efficient nutrient use, and food security. This study aims to delve into the effects of the use of different mulching techniques, both traditional and with an innovative ecological and sustainable mulch called hydromulch, on soil quality parameters, gas-exchange parameters and the final quality of the artichoke fruit (Cynara cardunculus subsp. scolymus L. (Heigi) cv. Symphony), as well as its impact on the metabolomics profile. The experimental design consisted of three blocks, each with three treatments: traditional polyethylene (PE) mulch, a rice husk-based hydromulch, and a bare soil control. The results show an increase in the physical quality of the artichokes grown with both mulches, as well as a direct impact on the primary and secondary metabolism, being more pronounced in the artichokes grown with hydromulch. In particular, hydromulch significantly up-regulated metabolites associated with the melatonin, serotonin, and polyamine pathways, suggesting a marked metabolic response compared with both polyethylene mulch and bare soil treatments. Furthermore, soil organic carbon (SOC) and soil organic matter (SOM) were increased in hydromulched soils. Gas exchange measurements revealed that hydromulched plants reduced stomatal conductance and transpiration, resulting in enhanced intrinsic water use efficiency. These improvements contribute to the production of high-quality, nutritionally enriched crops with direct relevance to food safety and sustainable agri-food systems. Full article

This study investigates how nitrogen form (100/0 NO₃⁻ vs. 50/50 NO₃⁻/NH₄⁺), heat stress (43 °C), and foliar proline application interact to modulate the growth, photosynthesis, and nitrogen metabolism of two tomato cultivars (Solanum lycopersicum L.), ‘Cherry’ and ‘Tres Cantos’. Nitrogen-exclusive nutrition optimized biomass accumulation and photosynthetic efficiency. Conversely, mixed nutrition reduced photosynthetic performance but enhanced nitrogen storage and detoxification pathways, as evidenced by a shift in amino acid profiles (decreased glutamate and aspartate alongside increased glutamine and asparagine). Under heat stress, growth declined; however, plants exhibited non-stomatal photosynthetic acclimation. While exogenous proline failed to increase biomass, it significantly enhanced heat tolerance by driving transpiration and evaporative cooling. Cultivar-specific assessments revealed high metabolic plasticity in ‘Cherry’, whereas ‘Tres Cantos’ adopted a conservative strategy centered on the accumulation of protective nitrogenous compounds. Full article

In this study, a water-based epoxy curing agent was prepared using polyamines (mixed amines), and epoxy coatings were formulated by blending this with a polyurethane-toughened water-based epoxy curing agent in specific proportions. By testing the tensile properties of the water-based epoxy coatings, the curing agent ratio was adjusted and the curing process optimised. A layer of water-based epoxy coating was applied to both the rebar electrodes and the rebar surfaces. Through electrochemical testing, coating thickness measurement, and coating continuity testing, the effects of filler type, particle size, and content on coating performance were investigated. On this basis, steel bars coated with a water-based epoxy coating containing 0.3% graphene–polyaniline composite nanomaterials were used as the control group, whilst a water-based epoxy coating incorporating a silane solution served as the primer. Based on the results of the preliminary screening, a water-based epoxy coating containing 1% silane coupling agent and 10% zinc phosphate was selected as the intermediate coat, whilst a water-based epoxy coating containing fly ash microspheres and polystyrene microspheres was selected as the top coat. Through cold bending tests and tensile strain tests on the coated reinforcing bars, the study investigated the effects of zinc phosphate, fly ash microspheres, and polystyrene microspheres on the cold bending performance and deformation combination performance of the water-based epoxy-coated reinforcing bars. By optimising the curing process, the tensile strength of the coating reached 40.11 MPa, with an elongation at break of 19.94%; the corrosion resistance of the zinc phosphate composite coating (corrosion current density: 0.00589 μA/cm²) was comparable to that of the 0.3% graphene/polyaniline coating; and the fly ash microsphere top coat significantly improved the deformation compatibility between the reinforcing bars and the coating. The high-performance, cost-competitive water-based epoxy coating system developed in this study offers a new technical approach to the durability protection of reinforced concrete structures in marine environments. Full article

Polyamine treatments are beneficial against various stress factors due to direct protective effects and the regulation of metabolite remodelling and gene expression. However, their protective, specific effects as priming under stress conditions remain not fully understood. We hypothesised that the positive effect of priming decreases even shortly after priming. To investigate the duration of action of putrescine treatment against osmotic stress, and to reveal species- and time-dependent differences, the effects of putrescine seed-soaking were monitored in wheat and maize during osmotic stress. The putrescine pre-treatment was effective in both species against osmotic stress during three trials ran in parallel, even when the stress was applied 7 days after seed-soaking. Leaves and roots responded differently, and putrescine induced certain unique changes under control and osmotic stress conditions. The effects of the treatments at the metabolite level changed between the sub-experiments and differed between the two species. Putrescine alone had an increasing effect on jasmonic acid-isoleucine level in the roots of both wheat and maize, and it induced the expression of WRKY97 in both the leaves and roots of maize plants throughout the experiment. These results highlight that different hormonal and transcriptional changes induced by putrescine were associated with the observed positive effects. Full article

While Peribacillus simplex has been reported to alleviate abiotic stress-induced damage in diverse plant species, its precise functional mechanism in mediating salt tolerance in asparagus remains unclear. The present study sought to uncover the molecular regulatory mechanisms through which strain P10 enhances the salt adaptability of asparagus seedlings. We investigated physiological responses, as well as transcriptomic and metabolomic alterations, in P10-inoculated asparagus seedlings grown under saline conditions. The results demonstrated that P10 inoculation alleviated salt-induced physiological damage by enhancing antioxidant enzyme activities and promoting the accumulation of osmotic regulatory substances. Comparative transcriptomic and metabolomic analyses identified 1659 differentially expressed genes (DEGs) and 128 differentially accumulated metabolites (DAMs) between P10-inoculated and non-inoculated seedlings under salt stress. These DEGs were primarily associated with multiple biological pathways, including phenylpropanoid biosynthesis, nitrogen metabolism, and flavonoid biosynthesis pathways (flavone, flavonol, and total flavonoid synthesis). Metabolomic profiling indicated that organic acids constituted the most abundant class of DAMs, followed by amino acids and their derivatives, and flavonoids. Integrated transcriptomic and metabolomic analyses suggested that P10 optimized the amino acid metabolic network under salt stress by upregulating genes involved in nitrogen assimilation, glutathione biosynthesis, and polyamine biosynthesis, thereby promoting amino acid accumulation and enhancing glutathione and polyamine levels. In addition, P10 markedly stimulated flavone and flavonol biosynthesis while maintaining elevated anthocyanin levels. Overall, P10 mitigated salt stress injury in asparagus by regulating amino acid metabolism to improve osmotic balance and growth stability, while simultaneously redirecting phenylpropanoid flux toward flavone and flavonol biosynthetic pathways to fine-tune stress responses. Full article

This meta-analysis combined the results of 61 independent studies published in 2005–2025 to examine polyamine-mediated responses to aluminum, cadmium, lead, chromium, copper, manganese, and selenium stress in plants. The logarithm ratio of responses (lnRR) under the random-effects model was used to calculate the effect sizes. Polyamine application significantly (p < 0.001) enhanced plant growth, with strong increases in root elongation (lnRR = 0.490, 95% CI: 0.362–0.618), fresh weight (lnRR = 0.413, 95% CI: 0.347–0.480), and dry weight (lnRR = 0.475, 95% CI: 0.409–0.541). Oxidative stress was markedly reduced, as reflected by decreases in reactive oxygen species accumulation (lnRR = −0.585, 95% CI −0.682 to −0.487, p < 0.001), hydrogen peroxide content (lnRR = 0.005, 95% CI −0.244 to 0.254, p = 0.968), and lipid peroxidation (lnRR = −0.487, 95% CI −0.578 to −0.397, p < 0.001). The antioxidant defenses were strengthened, and the levels of superoxide dismutase (lnRR = 0.468, p < 0.001) and catalase activity (lnRR = 0.373, p < 0.001) increased significantly. Metal accumulation was consistently reduced in polyamine-treated plants (lnRR = −0.392, 95% CI −0.460 to −0.324, p < 0.001). Supplementary genetic-level data indicated that metal stress triggers polyamines to regulate metal transporters, polyamine biosynthesis genes, antioxidant-related genes, and hormone-signaling pathways. Collectively, these data points make polyamines a key controller of plant metal stress tolerance and offer a quantitative and mechanistic system to apply them to metal-impacted agroecosystems. Full article

To address the common drawbacks of polyamine-based CO₂ absorbents, such as high viscosity and precipitation at high CO₂ loading, a novel liquid–liquid biphasic absorbent composed of triethylenetetramine (TETA), 1-(2-aminoethyl)piperazine (AEP), N,N-dimethylacetamide (DMAC), and H₂O was developed in this study. By comprehensively evaluating CO₂ saturation loading, phase separation behavior, rheological properties of the CO₂-rich phase, precipitation suppression, and desorption–regeneration performance, the optimal absorbent formulation was identified as 20 wt% TETA + 10 wt% AEP + 40 wt% DMAC + 30 wt% H₂O. The optimized system enabled more than 98% of the CO₂ absorption products to be concentrated in the lower phase, which accounted for only 56% of the total liquid volume. Compared with the AEP-free TETA/DMAC/H₂O system, the optimized AEP-modified absorbent effectively eliminated precipitation and reduced the viscosity of the CO₂-rich phase to 62.3 mPa·s, while also improving the desorption behavior and cyclic stability of the system. In addition, ¹³C NMR analysis suggested that the salting-out effect is the main driving force for phase separation, with ionic products preferentially enriched in the aqueous phase to form the CO₂-rich lower phase. AEP contributes to viscosity reduction, precipitation suppression, and enhanced regeneration by weakening carbamate aggregation through steric hindrance and promoting bicarbonate formation. Full article

Background: Spermidine is involved in a wide range of cellular processes, including mammalian oocyte development. Wheat germ is a natural source of polyamines and contains high concentrations of spermidine. However, no studies have evaluated the effects of wheat germ-derived spermidine on the regulation of mammalian ovarian function. The present study aimed to investigate the effect and underlying mechanism of wheat germ-derived spermidine on mammalian ovarian function. Methods: A feeding trial was carried out on mice with diets supplemented with varying concentrations of spermidine. The underlying mechanism by which spermidine exerts its beneficial effects on ovarian function and fertility in mice was explored through the integration of serum metabolomics and intestinal microbiomics analyses. Results: The results showed that dietary spermidine-rich feed significantly increased spermidine absorption and affected the metabolism of spermine and putrescine in the intestines. Dietary intake of low-concentration spermidine significantly increased the number of pups per litter and the secretion levels of estradiol (E2), progesterone (P4), luteinizing hormone (LH), and anti-Müllerian hormone (AMH). Furthermore, compared with a normal diet, spermidine supplementation resulted in significantly higher ovarian reserves and fewer atretic follicles. Correspondingly, metabolomics analysis revealed that spermidine primarily affected lipid metabolism and endocrine functions related to reproduction. In addition, dietary spermidine significantly altered the structural composition of the gut microbiota. Correlation analysis demonstrated that the abundance of Oceanisphaera, Atopostipes, and Actinobacteriota was significantly positively correlated with the secretion of E2, P4, and LH. Conclusions: Overall, these findings yield phenotypic insights into spermidine’s mediation of mammalian reproductive performance and offer a potential therapeutic strategy for individuals with reproductive dysfunction. Full article

The connection of a dianionic 2,2’-biimidazolate (biim²⁻) bridging unit to cis-[Cr(N^∩N)₂]³⁺ (N^∩N is a chelating didentate ligand) or cis-[Cr(N^∩N^∩N^∩N)]³⁺ building blocks (N^∩N^∩N^∩N is a chelating tetradentate ligand) produces heteroleptic pseudo-octahedral [CrN₆]⁺ chromophores. Their reduced cationic charge is compatible with the subsequent complexation of trivalent lanthanides (Ln³⁺) to give d-f {[(N^∩N)₂Cr(biim)]_nLn}⁽³⁺ⁿ⁾⁺ (n = 1–4), {[(N^∩N)₂Cr(biim)]Ln(Tp)₂}²⁺ and {[(N^∩N^∩N^∩N)Cr(biim)]Ln(Tp)₂}²⁺ adducts (Tp is tri(1H-pyrazol-1-yl)-λ⁴-borate). Moving from polyaromatic N^∩N (1,10 phenanthroline) to saturated N^∩N^∩N^∩N polyamine (cyclam) receptors controls the photophysical properties and leads to tunable light conversion in the target heterometallic complexes when Eu(III) is exploited as the activator for downshifting and Er(III) as the activator for upconversion. Full article

Epstein–Barr virus (EBV) lytic reactivation contributes to the pathogenesis of EBV-associated epithelial malignancies, including nasopharyngeal carcinoma and gastric carcinoma, highlighting the need for therapeutic strategies targeting viral reactivation. Capsaicin exhibits anticancer and antiviral activities; however, its effects on EBV lytic reactivation remain unclear. This study investigated the effects of capsaicin on EBV lytic reactivation in EBV-positive epithelial cancer models. Capsaicin significantly suppressed the expression of lytic genes, including BZLF1, BRLF1, BMRF1, and BLLF1, and reduced EBV virion production. Proteomic analysis revealed alterations in host cellular pathways associated with metabolism, chromatin organization, and cytoskeletal regulation, whereas metabolomic profiling demonstrated perturbations in nucleotide, amino acid, and polyamine metabolism processes involved in viral DNA replication and protein synthesis. Protein–protein interaction network analysis identified key host proteins, including HSP90AB1, MYH9, and ANXA2, implicated in metabolic reprogramming, cytoskeletal organization, and stress responses. Moreover, upstream regulators associated with EBV lytic activation, including p65, AP-1, HIF-1α, and SP1, were down-regulated following capsaicin treatment. Collectively, these findings demonstrate a multitarget inhibitory effect of capsaicin on EBV lytic reactivation and support its therapeutic potential against EBV-associated epithelial malignancies. Full article

Plant aging and senescence are key determinants of lifespan, yet the coordinated changes in endogenous polyamines and hormones during long-lived tree aging remain largely unclear. Cinnamomum camphora exhibits sequential senescence from leaves to trunk, with leaf physiology shifting toward senescence around 450 years. This study aimed to clarify the patterns of polyamines and hormones across a wide age gradient (10–810 years) and their associations with aging in ancient C. camphora. Newly expanded leaves were analyzed using curve fitting, correlation, regression, and path analysis. Tree age significantly influenced most polyamine and hormone indices, except for indole-3-acetic acid (IAA), abscisic acid (ABA), and salicylate glucoside (SAG). Spermidine (Spd) and gibberellic acid (GA) were negatively correlated with aging, and cytokinin (CK) and cadaverine (Cad) were positively correlated with aging. Free salicylic acid (SAF) was closely related to the senescence transition point. Polyamines and hormones interacted strongly. Cad was positively correlated with CK, and Spd was positively correlated with GA. A model combining Spd, GA/ABA, and CK/GA reliably predicted ancient tree age. Overall, Spd and CK exhibited the strongest negative and positive correlations with aging, respectively, providing insights into the physiological regulation of longevity in ancient trees. Full article

Both the gut and the lungs possess a microbiome, a community of commensal bacteria, archaea, fungi, and viruses that perform important housekeeping functions in those organs. The colonic microbiome primarily ferments indigestible dietary fibers into essential short-chain fatty acids, synthesizes essential vitamins, regulates the mucosal immune system, and forms a protective barrier against pathogenic colonization. The lung microbiome maintains respiratory health primarily by regulating mucosal immunity, providing a physical barrier against invading pathogens, and producing beneficial metabolites. Several colonic microbiota metabolites, including the short-chain fatty acids acetate, propionate, and butyrate, together with the tryptophan metabolites indole-3-acetate and indole-3-propionate, secondary bile acids, and the polyamines spermidine and putrescine, are transported to the lungs via the gut–lung axis. These colonic microbiota biomolecules suppress lung inflammation, strengthen immune homeostasis, and reduce the severity of respiratory diseases. In contrast, lung microorganisms and their metabolites can travel to the gut via the gut–lung axis, influencing intestinal immune responses and potentially leading to an imbalance of gut microorganisms or dysbiosis. This means that respiratory diseases may lead to digestive issues, intestinal inflammation and chronic diseases. Here, we have reviewed this crosstalk and its impact on the principal pulmonary diseases: asthma, chronic obstructive pulmonary disease, cystic fibrosis, bronchogenic carcinoma, COVID-19, interstitial lung diseases, pneumonia, and tuberculosis. It is concluded that the gut microbiome plays a significant part in lung health and disease. Diet, tobacco smoking and electronic cigarette vaping all impact both the gut and lung microbiomes. Full article

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease of the pulmonary vasculature characterized by obliterative remodeling of small pulmonary arteries, leading to sustained elevation of pulmonary vascular resistance, right ventricular failure, and premature death. The diagnostic gold standard remains right heart catheterization, requiring a mean pulmonary artery pressure greater than 20 mmHg at rest, a pulmonary arterial wedge pressure of 15 mmHg or below, and a pulmonary vascular resistance exceeding 2 Wood units. PAH is an autosomal dominant disorder with markedly incomplete penetrance of approximately 20–30%, indicating that germline mutations alone are insufficient to cause disease. Disease manifestation requires additional “second hits”, including chronic hypoxia, systemic inflammation, hemodynamic stress, hormonal influences, and common genetic modifiers such as single-nucleotide polymorphisms (SNPs). This genetic and environmental complexity underpins the broad clinical heterogeneity observed across PAH subtypes, which include idiopathic PAH, heritable PAH, and disease associated with connective tissue disorders, HIV infection, portal hypertension, congenital heart disease, schistosomiasis, and drug or toxin exposure. This review provides a comprehensive and critical appraisal of the molecular-genetic architecture of PAH. Thirty genes have now been implicated in disease pathogenesis, spanning seven functional categories: receptors of the TGF-β/BMP signaling family (BMPR2, ACVRL1, ENG, BMPR1B); circulating BMP ligands (GDF2, BMP10); transcription factors (TBX4, SOX17, KLF4, FOXF1, SMAD1, SMAD4, SMAD9); membrane and polyamine transporters (ATP13A3, AQP1); potassium channel regulators (KCNA5, KCNK3, ABCC8); metabolic and mitochondrial genes (EIF2AK4, NFU1, GGCX); signaling receptors and structural proteins (NOTCH3, KDR, CAV1, PLEKHH2); vasoactive and extracellular matrix regulators (KLK1, CBLN2, CD248); and epigenetic regulators (TET2, TOPBP1). Among these, BMPR2 is the dominant contributor, accounting for 53–86% of heritable PAH and 14–35% of idiopathic cases. The remaining genes each account for fewer than 5% of cases individually, collectively reflecting a broad landscape of rare and ultra-rare genetic contributions. For each gene, we critically evaluate the strength of genetic evidence, pathogenic mechanisms, degree of mechanistic resolution, and clinical relevance. We further discuss the contribution of emerging technologies, including whole-genome sequencing, single-cell and spatial transcriptomics, multi-omics integration, iPSC-derived vascular models, and artificial intelligence, to expanding the PAH genetic architecture beyond single-gene discovery. A key theme across this landscape is convergence: despite mechanistic diversity at the gene level, most PAH-associated variants ultimately impair endothelial quiescence, promote smooth muscle proliferation, and drive apoptosis resistance through disruption of BMP signaling amplitude, transcriptional stability, ion channel homeostasis, metabolic integrity, or epigenetic regulation. This convergence supports both a unified therapeutic rationale and a precision medicine framework for genotype-stratified intervention in PAH. Full article