Search Results (549)

Polyamines, putrescine, spermidine and spermine, are essential polycationic metabolites present in all eukaryotic cells, where they regulate fundamental processes including nucleic acid stabilization, translation, and stress responses. Spermidine synthase (SPDS), a member of the aminopropyltransferase (APT) family, catalyzes the transfer of an aminopropyl group from decarboxylated S-adenosylmethionine (dc-SAM) to putrescine to form spermidine. Although genomic analyses predict the presence of SPDS homologs in multiple fungal species, polyamine biosynthesis has not been experimentally characterized in the multidrug-resistant fungal pathogen Candidozyma auris. Here, we report the biochemical and functional characterization of the C. auris spermidine synthase, CauSpe3. The CauSPE3 gene complemented a Saccharomyces cerevisiae spe3Δ mutant demonstrating conserved function in vivo. Recombinant CauSpe3 was expressed in Escherichia coli, purified and analyzed using the fluorescence-based DAB-APT assay, which uses 1,2-diacetylbenzene (DAB) for polyamine detection. CauSpe3 catalyzed efficient conversion of putrescine to spermidine in the presence of dc-SAM, with K_half values of 65.5 ± 7.11 µM for putrescine and 66.9 ± 2.09 µM for dc-SAM, and V_max values of 7.1 ± 0.57 and 7.9 ± 0.12 nmol·µg⁻¹·min⁻¹, respectively. A catalytic-site mutant and heat-inactivated enzyme showed no detectable activity, and product formation was confirmed by means of thin-layer chromatography and mass spectrometry. These findings establish CauSpe3 as a functional spermidine synthase. Full article

Background/Objectives: Carbon dots (CDs) are promising antimicrobial nanomaterials owing to their biocompatibility, environmental friendliness, and tunable surface chemistry. This study aimed to synthesize nitrogen-doped CDs (AS-CDs) and develop a light-responsive antibacterial system through conjugation with chlorin e6 (Ce6). Methods: AS-CDs were synthesized by a microwave-assisted method using L-ascorbic acid and spermidine, followed by conjugation with Ce6. The materials were characterized by transmission electron microscopy, zeta potential analysis, and spectroscopic methods, and their antibacterial activity was evaluated against Escherichia coli, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) under both dark and visible-light conditions. Cytotoxicity was assessed using HaCaT cells. Results: The AS-CDs exhibited a uniform nanoscale morphology with an average diameter of 6.3 nm and a positive surface charge of +15.6 mV, together with intrinsic broad-spectrum antibacterial activity. Ce6 conjugation further enhanced antibacterial efficacy under light irradiation, with the CDs-Ce6 conjugate achieving complete eradication of S. aureus and MRSA and marked inhibition of E. coli at 2.5 μg/mL. Cytotoxicity studies demonstrated low toxicity in HaCaT cells within the effective antibacterial concentration range. Conclusions: These findings highlight the potential of microwave-synthesized, photosensitizer-conjugated CDs as next-generation antimicrobial agents. This platform offers a cost-effective, sustainable, eco-friendly, and efficient platform for combating bacterial infections, with broader potential in pharmaceutical and biomedical applications. Full article

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease marked by progressive degeneration of motor neurons and skeletal muscle. Gene expression analysis of the spinal cord and gastrocnemius of the SOD1-G93A ALS mouse model revealed a strong increase in inflammatory pathways and, specifically in the ALS gastrocnemius, a decrease in mitochondrial transcription and an increase in ribosomal protein expression. Treatment of ALS mice with the polyamine spermidine (SPD), a promising molecule in combating neurodegeneration and muscle atrophy, is able to partially restore the expression of more than four thousand genes in gastrocnemius tissue, including the mitochondrial regulator Pgc1α, as well as all the mitochondrial encoded genes and a large class of ribosomal proteins. SPD enhanced mitochondrial bioenergetics, as evidenced by Seahorse experiments, and delayed muscle weakness in vivo, as shown by grip strength records. These findings suggest that SPD can act as a potential supplement in the therapeutic strategy for ALS, offering a foundation for further research to improve patient outcomes. Full article

Tumor microenvironments, particularly hypoxia and inflammation, heavily influence colorectal cancer (CRC) pathogenesis by altering polyamine metabolism. Identifying natural compounds targeting these vulnerabilities remains critical. Integrating untargeted metabolomics, network pharmacology, and a human endogenous metabolite library screen, we identified apigenin (API) as a potent anti-CRC candidate. API significantly inhibited the proliferation, migration, and invasion of RKO and HCT116 cells in vitro and suppressed xenograft tumor growth in vivo. Crucially, high-throughput screening revealed that polyamines rescued CRC cells from API-induced cytotoxicity. Mechanistically, API exerts its effects by dismantling a newly identified HIF-1α/SMOX positive feedback loop. In CRC, HIF-1α transcriptionally activates spermine oxidase (SMOX), while SMOX-driven polyamine metabolism fuels the TLR4/MyD88 inflammatory cascade to continuously stabilize HIF-1α. API acts as a “circuit breaker” for this axis, significantly reducing the spermidine/spermine ratio and downregulating inflammatory signaling. Ultimately, API effectively remodels polyamine metabolism and suppresses CRC progression by disrupting the HIF-1α/SMOX and TLR4/MyD88 pathways, offering a novel metabolic mechanism for API in CRC therapy. Full article

Non-motor symptoms of PD impair quality of life and remain challenging to treat. Here, we examined the effects of short- (38 days) and long-term (178 days) supplementation with the natural polyamine spermidine on anhedonia and anxiety-like behaviours in a 6-hydroxydopamine-induced rat model of PD and linked them with spermidine’s anti-inflammatory properties. Behavioural assessments (cylinder, sucrose preference, elevated plus-maze tests) were conducted during progressive neurodegeneration and after oral treatment. Under the same conditions, peripheral inflammation was evaluated by the total leukocytes and their subpopulation numbers (hematological analysis) and by CD4⁺ and CD8⁺ T lymphocyte percentages (imaging flow cytometry); the plasma levels of interleukins 4 and 10 and corticosterone (enzyme-linked immunosorbent assay) were also evaluated. The safety of long-term supplementation was assessed using standard biochemical markers (chemistry analyser). Both treatment regimens reversed 6-hydroxydopamine-induced lymphopenia. Long-term spermidine treatment increased the number of TCD4⁺ lymphocytes and monocytes and elevated the plasma concentrations of IL-4 and IL-10, while reducing corticosterone levels. These immunomodulatory effects were associated with reduced anhedonia and anxiety. All of the biochemical safety parameters remained within normal ranges. Spermidine alleviates neuropsychiatric symptoms in a rat model of progressive neurodegeneration in the nigrostriatal system through its regulatory influence on peripheral immune responses. Exploring the systemic mechanisms underlying spermidine’s effects could unveil innovative supplementation strategies and expand treatment options for managing symptoms in PD. Full article

The molecular characterization of embryogenic cultures helps us to understand the physiology of somatic embryogenesis and the events related to the occurring cell reprogramming and then to optimize protocols for this process. The present work seeks to contribute to these aims by biochemically defining embryogenic and non-embryogenic cell suspensions of two commercial bananas: Musa spp. cvs. ‘Grande Naine’ (AAA) and “FHIA-18” (AAAB). Thus, two types of putative biochemical indicators of embryogenic potential were studied: (i) major intracellular polyamines—1,3-diaminopropane (DAP), putrescine (Put), spermidine (Spd), and spermine (Spm)—taking into account their type of linkage with other molecules, and (ii) released endochitinase EP3-like proteins. Polyamine profiles of embryogenic and non-embryogenic cultures were analyzed using high-performance liquid chromatography (HPLC) with fluorescence detection, whereas immunoanalytical techniques (dot and Western blot) allowed the evaluation of the association of EP3-like proteins with different stages of somatic embryogenesis. The results indicated that polyamine contents and ratios discriminate the capacity for somatic embryogenesis and differentiation/proliferation status in cell suspensions. For example, the absence of Spm in the insoluble conjugate fraction of polyamines, lower Put contents (less than 1000 nmol per gram of fresh mass), and a lower free Put/Spm ratio (less than 1) were indicative of embryogenic cell suspensions when compared with those that were non-embryogenic and more proliferative. Furthermore, EP3-like proteins of banana were mainly released in highly embryogenic cultures. This supports the important role of EP3-like proteins in the viability of plants, since these enzymes are found to be related to somatic embryogenesis in a wide range of plant species. Full article

Phenolamides in bee pollen exhibit notable bioactivities, such as antioxidant, anti-inflammatory, and antimicrobial effects. Ulcerative colitis (UC) is a prevalent intestinal disorder, while the potential effects of phenolamides on UC remain unclear. This study aims to investigate the effects and mechanisms of phenolamide extract (PAE) from apricot bee pollen on dextran sulfate sodium (DSS)-induced UC in mice. Firstly, we analyzed the main compounds of PAE. Mice were treated with PAE (100, 200, and 400 mg/kg bw) both during the 7 days preceding 2.5% DSS induction and throughout the induction period (7 days). The results show that the primary compounds of PAE were isomers of tri-p-coumaroyl spermidine (97.78 ± 2.76%). A biochemical analysis showed that PAE decreased the levels of pro-inflammatory cytokines and increased the activities of antioxidant enzymes. Regarding the gut microbiota, PAE reduced the Bacillota/Bacteroidota ratio. Additionally, PAE elevated beneficial bacteria, including norank_f_Muribaculaceae, norank_o_Clostridia_UCG-014, and Lachnospiraceae_NK4A136_group, while reducing harmful bacteria, including Escherichia-Shigella, Clostridium, and Romboutsia. A quantitative analysis of short-chain fatty acids (SCFAs) demonstrated that PAE intervention promotes the biosynthesis of SCFAs in UC mice. This study first demonstrates that PAE attenuates DSS-induced colitis by modulating gut microbiota and SCFAs, suggesting its potential as a functional dietary supplement for colitis. Full article

Alterations in tight junction (TJ) organization and dysregulation of cancer stem cell (CSC)-associated markers are increasingly recognized as molecular features linked to colorectal cancer (CRC) progression, heterogeneity and clinical outcome. Bioactive dietary compounds such as spermidine (SPD) and eugenol (EUG) have been proposed as modulators of cancer-related molecular pathways; however, their combined effects on CRC spheroid models relevant to molecular characterization remain insufficiently defined. In the present study, the molecular impact of SPD and EUG, administered individually or in combination, was evaluated in primary and metastatic CRC spheroids. First-generation spheroids derived from Caco-2 and SW620 cells were exposed to SPD, EUG, or SPD+EUG at the time of seeding, and spheroid growth and self-renewal capacity were monitored across successive generations. The expression of TJ- and CSC-associated markers was assessed at both the transcript and protein levels using reverse transcription–quantitative polymerase chain reaction (RT-qPCR), Western blotting and immunohistochemistry. The combined SPD+EUG treatment was associated with a marked reduction in spheroid area and self-renewal capacity in both CRC models. Baseline molecular profiling revealed higher TJ marker expression in Caco-2 spheroids and enrichment of CSC-associated markers in SW620 spheroids. Treatment-induced modulation of CSC- and TJ-related transcripts was observed; however, transcript-level changes were not consistently mirrored at the protein level, indicating the involvement of post-transcriptional regulatory mechanisms. In particular, Occludin (OCLN), Zonula occludens-1 (ZO-1), CD133, ALDH1A1, SOX2 and VE-cadherin exhibited divergent RNA and protein expression patterns depending on cell type and treatment condition. Collectively, these findings underscore the relevance of three-dimensional CRC spheroid models for molecular profiling studies and highlight the importance of integrating transcript- and protein-level analyses when evaluating bioactive compounds with potential diagnostic and translational relevance in colorectal cancer. Full article

Ornithine decarboxylase (ODC) functions as the rate-limiting enzyme in the polyamine (PA) biosynthetic pathway. It catalyzes the decarboxylation of L-ornithine to produce putrescine, thereby initiating the biosynthesis of polyamines. Polyamines are a class of widely distributed polycationic aliphatic compounds in living organisms, including putrescine, spermidine, and spermine. They serve not only as critical regulators of cell growth, proliferation, and differentiation, but also as important signaling molecules involved in plant responses to environmental stress and key precursors in the biosynthesis of diverse secondary metabolites. Focusing on recent advances in plant ODC research, this review summarizes the characteristics and evolutionary relationships of the ODC gene family, the biochemical properties and catalytic mechanism of the enzyme, and its multiple physiological roles in growth, development, secondary metabolism, and stress adaptation. Furthermore, we discuss the complex regulatory mechanisms governing ODC activity at both transcriptional and post-translational levels, with a critical gap in understanding the post-translational regulation of ODC in plants, particularly the mechanisms governing its degradation. Unlike in animals, where antizymes mediate ODC degradation, functional analogs of antizymes have not yet been identified in plants, leaving the degradation pathway largely unexplored. Finally, we review the applications of plant genetic modification targeting ODC in enhancing the production of valuable secondary metabolites in medicinal plants and improving stress tolerance in crops, along with perspectives on future research directions. This review illustrates the diversity of ODC functions and the complexity of its regulatory mechanisms in plant growth, development, stress responses, and secondary metabolism. It also provides a theoretical foundation and insights for exploring ODC as a target for plant genetic modification, which is promising for improving the economic traits and stress resistance of horticultural plants. Full article

Background: Citrus components potentially suppress adipogenic differentiation and lipid accumulation, and exhibit anti-inflammatory and antioxidant effects. We hypothesized that the bioactive compounds in Citrus junos Sieb ex Tanaka (yuzu) fruit peel can alter the systemic metabolism and productivity of beef cattle. Methods: Japanese Brown (JBR) steers were fed with a diet supplemented with 2.5% yuzu peel during the last month of the finishing period. To investigate the effect of dietary yuzu supplementation (DYS) on beef and liver metabolism, we explored the metabolomic profiles of longissimus thoracis (LT, loin) muscle at 14 d postmortem using capillary electrophoresis (CE-TOF/MS) and high-performance liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS). Results: The DYS treatment enhanced the beef fat score compared to that recorded in beef in the no-DYS (None) group (p = 0.050); however, the other carcass quality traits were not significantly different between the DYS and None groups. CE-TOF/MS and LC-TOF/MS revealed 242 and 107 annotated peaks, respectively, for the LT muscle. DYS significantly increased 9(S)-hydroxyoctadecadienoic acid (9-HODE, a beef flavor precursor), cyclo(-Leu-Pro), spermidine, asymmetric dimethylarginine, and 7α-hydroxycholesterol levels and reduced 2-ethylhydracrylic acid (2-EHAA), γ-tocopherol, coenzyme Q10 (CoQ10), sphingomyelin(d18:1/16:0), Cys-Gly, Tyr-Arg, and palmitoylcarnitine levels in postmortem LT muscle (p < 0.050). Concomitantly, in the fresh liver, DYS increased acetyl-CoA, 6-phosphogluconic acid, S-methylglutathione, ATP, ribulose 5-phosphate, and ADP levels and suppressed the content of thiamine, Ala-Ala, riboflavin, and ascorbate 2-sulfate (p < 0.050). Conclusion: Collectively, yuzu ingredients activated ATP production in the liver through the elevation of hepatic energy metabolism primarily in the citrate cycle and β-oxidation, and potentially altered muscle metabolism, including linoleic acid oxidation, FAD-mediated electron transport chain, and isoleucine catabolism, as demonstrated in the reduced accumulation of 2-EHAA and CoQ10 in DYS beef. Moreover, DYS likely affects the gut microbiome by enhancing the production of cyclo(-Leu-Pro), an antimicrobial dipeptide. Full article

Polyamines, such as spermidine (Spd), are small aliphatic amines that play critical roles in plant growth, fruit development, and stress responses. Spermidine synthase (SPDS) is the enzyme responsible for catalyzing Spd biosynthesis. However, the functional characterization of SPDS genes in tomato (Solanum lycopersicum) has been less studied. In this study, four SlSPDS genes (SlSPDS1-4) were identified and analyzed for their physicochemical properties, phylogenetic relationships, promoter cis-acting elements, subcellular localization, responses to various abiotic stresses, and effects on polyamine content in tomato leaves. Promoter analysis revealed the presence of multiple hormone and stress-responsive elements. Simultaneously, the overexpressing lines were subjected to osmotic stress treatment. Subcellular localization experiments demonstrated that SlSPDS1 and SlSPDS2 were distributed in both the nucleus and cytoplasm, while SlSPDS3 and SlSPDS4 were specifically localized to the nucleus. SlSPDS1-3 exhibited significant responses to high/low temperature stress, salt stress, and ABA stress. Meanwhile, only SlSPDS1 and SlSPDS4 exhibited responses to drought stress. Transient expression of SlSPDSs in tomato revealed changes in the accumulation levels of spermine, putrescine, tyramine, and tryptamine, whereas the contents of spermidine and phenethylamine showed no significant changes. Simultaneously, we successfully obtained four SlSPDS-overexpressing transgenic tomato lines, OE-SPDS1-4. Phenotypic analysis confirmed that these transgenic lines exhibited significantly reduced wilting and chlorosis compared with WT plants under drought and salt stress. Functional validation indicates that overexpression of these genes enhances reactive oxygen species (ROS) scavenging capacity in transgenic tomatoes, thereby potentially improving their tolerance to drought and salt stress. These findings highlighted the potential function of SlSPDS genes in tomato, providing valuable targets for improving stress tolerance. Full article

Background/Objectives: Leishmaniasis remains a major neglected tropical disease, and current chemotherapeutic options are limited by toxicity and resistance in Leishmania species, including L. amazonensis. Prenylated coumarins have emerged as promising bioactive scaffolds. Altissimacoumarin D and its analogues inhibit fungal efflux pumps associated with resistance. However, their antileishmanial potential and mechanisms of action remain unclear. Here, we evaluated the in vitro, in vivo, and in silico effects of altissimacoumarin D and seven analogues against L. amazonensis. Methods: In vitro assays were performed to identify active compounds and assess toxicity in keratinocytes. In vivo experiments in hamsters evaluated antileishmanial activity and renal and hepatic toxicity. In silico analyses were conducted to investigate the mechanism of action of the substances. Results: In vitro assays showed that ACS47, ACS48, and ACS51 were the most active and safe compounds. In a hamster infection model, daily administration of ACS47 and ACS48 (2.5 mg/kg) significantly reduced parasite burden and lesion size, while maintaining normal renal and hepatic biochemical parameters. Histological analysis correlated reduced lesion size with marked decreases in amastigote density. Based on in silico analysis, spermidine synthase was supported as a plausible molecular target. Conclusions: Collectively, these findings identify ACS47 and ACS48 as promising lead compounds for future antileishmanial drug development. Full article

Spermidine (SPMD) is essential for numerous cellular functions and crucial for sustaining diverse biological activities. However, its antioxidant capabilities are relatively weak. In this study, we overcame this limitation by examining the antioxidant and cellular effects of ascorbic acid (AA)-conjugated spermidine (AA-SPMD) in human skin keratinocyte and fibroblast cells. AA-SPMD was successfully fabricated using an optimized design and synthetic approach, and its stability, antioxidant activity, cellular responses, and collagen I production were evaluated. In addition, we assessed the protective effects of AA-SPMD from hydrogen peroxide and UVA-induced oxidative damage in human skin cells. The AA-SPMD showed high stability under rigorous conditions and exhibited strong antioxidant activity. AA-SPMD showed no cytotoxic effect even at a concentration of 1 mM. In addition, it can increase the rate of cell proliferation and migration in skin cells without reducing the inhibition of human keratinocytes (HaCaT) and human dermal fibroblasts (HDF) at concentrations of 10 μM. Moreover, AA-SPMD can increase the amount of collagen I synthesized in HDF cells, thereby influencing cell proliferation and migration. Based on our in vitro study, AA-SPMD is expected to be more effective than AA or SPMD alone, indicating its potential utility in biomedical and cosmetic applications. Full article

This study aimed to determine the regulatory role of polyamine–plant growth regulator (PGR) interactions on shoot development and caffeic acid derivatives (CADs) in in vitro shoot cultures of Echinacea purpurea and Echinacea pallida. Nodal explants were cultured under cytokinin-based (0.5 and 1.0 mg/L BAP) and auxin-containing (0.1 mg/L NAA) PGR combinations, supplemented with putrescine or spermidine at 50 and 100 mg/L. Shoot induction rate, number of shoots per explant, total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), and the contents of caffeic acid derivatives (caftaric acid, chlorogenic acid, caffeic acid, cichoric acid, and echinacoside) were quantitatively determined. The results revealed that shoot induction in both species was not statistically significant with respect to the PGR × polyamine interaction, and that shoot formation was primarily governed by the PGR composition. In contrast, pronounced species-specific differences were observed in secondary metabolism. In E. purpurea, overall phenolic and antioxidant indices remained relatively stable, whereas putrescine application, particularly under 0.5 mg/L BAP, induced a marked compositional redistribution of CADs, with maximum levels of cichoric acid (41.60 mg/g DW), chlorogenic acid (6.51 mg/g DW), and caffeic acid (0.23 mg/g DW). Conversely, E. pallida exhibited higher metabolic plasticity and responded more consistently to spermidine under auxin-containing media, where spermidine maximized chlorogenic acid (4.87 mg/g DW) and echinacoside (1.65 mg/g DW) accumulation alongside coordinated increases in TPC, TFC, and TAC. Overall, the results indicate that the polyamine-mediated modulation of caffeic acid derivatives in Echinacea species is strongly species- and hormone-dependent, underscoring the requirement for species-specific and PGR-conditioned optimization strategies in in vitro shoot culture systems. Full article

Intestinal aging is characterized by a gradual decline in epithelial renewal capacity, barrier function, immune balance, and metabolic regulation, often accompanied by shifts in gut microbial composition. Polyamines, including putrescine, spermidine, and spermine, are vital microbial–host metabolites that support intestinal cell growth, autophagy, immune modulation, and mucosal repair. With advancing age, both host-derived and microbiota-mediated polyamine production declines, contributing to intestinal dysfunction and heightened vulnerability to inflammation and age-related disorders. This review explores the diet–microbiota–polyamine axis as a key biological framework influencing intestinal aging. It aims to integrate evidence on how dietary components and functional foods shape gut microbial ecology and, in turn, regulate microbial polyamine biosynthetic pathways that impact intestinal health. The review highlights major microbial contributors to polyamine metabolism, particularly lactic acid bacteria, and outlines mechanistic pathways linking polyamines to epithelial regeneration, inflammatory control, and gut barrier maintenance. It further discusses how age-associated dysbiosis disrupts these interactions and evaluates nutritional and microbial-based strategies such as fermented foods, prebiotics, and probiotics that may enhance polyamine availability and restore gut homeostasis. From the standpoint of food microbiology and human physiology, this synthesis underscores the translational potential of targeting microbial polyamine production through diet-based interventions. This article presents a narrative review synthesizing experimental, animal, and emerging human evidence on microbial and dietary polyamines in intestinal aging. In conclusion, modulating the diet–microbiota–polyamine axis represents a promising strategy to promote healthy intestinal aging, meriting deeper mechanistic exploration and validation through clinical studies. Full article