Search Results (225)

No previous studies have characterized testicular polyamine metabolism across specific cell populations, including Sertoli cells, testicular peritubular cells, Leydig cells, germ cells, and testicular macrophages, during testicular maturation and aging. Here, we used immature, young adult, and aged adult Syrian hamsters as an animal model to quantify the main polyamines (PA) and their monoacetylated derivatives at the tissue and cellular levels by thin-layer chromatography and to assess the expression profiles of key genes involved in polyamine metabolism by RT-qPCR. At the tissue level, total PA concentration increased with age. During testicular maturation, putrescine increased and spermine decreased, whereas aged testes showed spermidine predominance. Testicular cell populations contributed unequally to PA production and release, and these contributions changed markedly with age. At the cellular level, aging was associated with a shift toward spermine- and N¹-spermine-rich profiles, suggesting enhanced PA catabolism, likely supported by Sat1/Paox up-regulation. Thus, PA catabolic enzymes represent potential therapeutic targets for aging-associated or even idiopathic infertility-related testicular alterations. Full article

Cadaverine is a lysine-derived diamine that remains less studied than the canonical plant polyamines putrescine, spermidine, and spermine. Its polycationic nature suggests it may influence membrane stability, ionic balance, redox regulation, and stress-related metabolic adjustments, but its specific contribution to plant resilience to abiotic stress remains poorly characterized. This systematic review, evidence map, and exploratory meta-analysis synthesized the published literature on cadaverine-associated responses in plants exposed to abiotic stress. The object of analysis was the existing body of literature, and the quantitative component summarized data extracted from eligible studies rather than generating new experimental results. The review examined whether the available literature supports a role for cadaverine beyond its description as a stress-associated metabolite, particularly regarding transport, oxidative stress mitigation, photosynthetic protection, water status, ionic homeostasis, and growth maintenance. The evidence indicates that cadaverine is primarily associated with beneficial physiological responses to stress, particularly when applied exogenously. However, the magnitude of the response varies across species, stress types, doses, application methods, and response variables. Mechanistically, cadaverine may contribute to stress tolerance by activating antioxidant enzymes, reducing oxidative damage, stabilizing membranes, protecting the photosynthetic apparatus, promoting osmotic adjustment, and modulating cation transport. However, endogenous cadaverine dynamics and several proposed signaling connections remain insufficiently validated. Overall, cadaverine emerges as a promising regulatory candidate for fundamental research on plant stress physiology. In contrast, its agronomic use still requires standardized dose–response studies, comparative analysis with other polyamines, and greenhouse and field validation. 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

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

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

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

Polyamines (PAs) play critical roles in plant growth, somatic embryogenesis (SE), etc. Previous studies have demonstrated that exogenous PAs could promote SE in plants. However, the effects of PAs on Ginkgo biloba L. SE are still unknown, especially in the switch from the initial callus (IC) to the embryogenic callus (EC) stage or to the globular embryo (GE) stage. This work identified 34 genes involved in PAs metabolism in G. biloba using genome-wide analyses. These genes were clustered into six families and found to be unevenly distributed across 11 of the 12 chromosomes on the plant. These families contain 539 cis-acting elements that mainly respond to phytohormones, abiotic stress, meristem expression, etc. RNAseq analysis revealed that the expression of GbADC2, GbSAMDC2, GbSPMS1, GbCuAO1 and 3, and GbPAO3, 8, 6 and 13 genes in G. biloba were higher in the GE stage than in the IC stage. In addition, 1.0 mg·L⁻¹ spermine (Spm3) could promote the conversion of IC to EC, while 0.01 mg·L⁻¹ putrescine (Put1) could facilitate the transition from IC to EC and then to GE. During the conversion of IC to EC or to GE, higher levels of abscisic acid (ABA), superoxide dismutase (SOD), and peroxidase (POD) and lower levels of indole-3-acetic acid (IAA), gibberellin (GA3), and zeatin (ZT) were observed; concurrently, the H₂O₂ level was also observed to be high. Gene expressions of GbSPMS2, GbCuAO3, and GbPAO6 and 8 were upregulated, while GbADC2 expression was downregulated in the EC or GE stages under Spm3- or Put1- treatment. These results illustrate that exogenous PAs might alter the levels of the endogenous polyamine pool and lead to H₂O₂ production, which caused a certain oxidative stress. However, SOD and POD balanced H₂O₂ production and maintained homeostasis. The PAs–H₂O₂–ABA module might coordinate the regulation of early in of G. biloba. These relations were discussed in this work. These findings provide a foundation for comprehending the roles of PAs gene families in the key nodes of early SE in G. biloba. Full article

Background: Polyamines, including putrescine (PU), spermidine (SPD), and spermine (SPM), are ubiquitous bioactive compounds essential for cell proliferation, genomic stability, autophagy, and the regulation of oxidative and inflammatory responses. Growing evidence, particularly for SPD, suggests that polyamine-rich diets may protect against age-related conditions such as cardiovascular disease, metabolic syndrome, and neurodegenerative disorders. As endogenous polyamine synthesis declines with age, dietary intake becomes increasingly important, especially in older adults. Methods: This study estimated each polyamine (PU, SPD and SPM) and total polyamine intake in the Spanish population using food consumption data from the Spanish Ministry of Agriculture, Fisheries and Food. Intakes were evaluated across four age groups, and major dietary sources were identified. Results: Total polyamine intake increased with age, reaching 393 µmol/day in adults over 65 years. PU accounted for 49% of total intake, followed by SPD (29%) and SPM (22%). Plant-based foods were the primary contributors to SPD intake, particularly vegetables (36%), fruits (26%), and cereals (18%). PU intake was also predominantly plant-derived, mainly from fruits (58%) and vegetables (23%), whereas SPM intake was largely associated with meat products (59%). A theoretical Mediterranean diet model yielded a slightly higher total polyamine intake of 406.6 µmol/day and a substantially greater SPD intake than that observed in older adults (193.99 µmol/day versus 121.62 µmol/day). Conclusions: Overall, estimated polyamine intake in the Spanish population fell below the optimal level of 540 µmol/day proposed in the literature. These findings highlight the need for public health strategies promoting consumption of polyamine-rich foods, particularly vegetables, legumes, whole grains, and fruits, to support healthy aging and reduce the risk of age-related diseases. Full article

Background: Prostate cancer remains a significant global health burden, yet current diagnostic reliance on PSA screening is heavily hampered by limited specificity and high rates of overdiagnosis. Methods: To address this clinical bottleneck, we utilized a highly sensitive Complete360^®-MyMeta targeted-metabolomics platform to perform high-resolution profiling of 43 metabolites across the carnitine, polyamine, and methylation networks in plasma from a discovery cohort of all-stage (I–IV) PCa patients and healthy controls. Results: Our analysis identified 28 significantly altered metabolites (p < 0.05), revealing profound systemic metabolic reprogramming characterized by the depletion of circulating TML and putrescine, alongside the elevation of L-acetylcarnitine and sarcosine. These systemic shifts are consistent with a localized tumoral “metabolic sink”, wherein upregulated mitochondrial TML import via the SLC25A45 transporter actively fuels fatty acid oxidation, while parallel androgen signaling drives massive polyamine synthesis. Translating these mechanistic insights into a clinical tool, we developed a multivariable diagnostic signature utilizing mathematically stable bipartite metabolic ratios. An optimized, cross-validated model combining L-acetylcarnitine/TML and sarcosine/putrescine effectively mitigated physiological noise to achieve robust diagnostic separation, yielding an area under the curve (AUC) of 0.99. Conclusions: Ultimately, this study provides a discovery-phase proof-of-concept for the SLC25A45-TML axis as a mechanistically grounded, stage-independent liquid biopsy, offering a rational, non-invasive framework to significantly improve PCa detection. Full article

This study compared intestinal polyamine metabolism and barrier function between Ningxiang (NX) and Duroc × Landrace × Yorkshire (DLY) piglets under baseline conditions and following ETEC challenge. Experiment 1 (baseline, n = 12/breed) assessed colonic barrier integrity, immune status, polyamines, and microbiota. Experiment 2 (ETEC challenge, n = 8/group/breed) evaluated responses to oral ETEC (10⁹ CFU) over 3 days. Under baseline conditions, NX piglets showed superior barrier integrity, higher goblet cell numbers and mucin 2 (MUC2) protein expression, and lower plasma levels of intestinal permeability markers—diamine oxidase (DAO), D-lactate (DLA), and endotoxin (ET)—compared with DLY piglets. NX piglets also exhibited reduced colonic pro-inflammatory cytokine levels (IL-6 and IL-1β) and higher expression of immune-related markers (CD3, CD68, and IgA) versus DLY piglets. In contrast, DLY piglets displayed more active microbial polyamine metabolism in the colon, with higher concentrations of putrescine, spermidine, and spermine, as well as increased ornithine decarboxylase (ODC) expression. 16S rRNA sequencing revealed greater microbial diversity and enrichment of taxa (Muribaculaceae_unclassified, Prevotella) in NX piglets, whereas DLY piglets showed enrichment of polyamine-associated genera (Collinsella, Veillonella). Following the ETEC challenge, DLY piglets displayed pronounced polyamine upregulation, including elevated polyamine levels and ODC1 expression. Conversely, NX piglets maintained more stable polyamine metabolism, higher expression of tight junction proteins (ZO-1 and occludin), lower plasma permeability markers, reduced pro-inflammatory cytokine expression (IL-6, IL-1β, IL-22), and increased anti-inflammatory IL-10 expression. Collectively, these findings demonstrate that NX piglets possess superior intestinal barrier integrity and immune maturity, while DLY piglets exhibit a more active but stress-responsive polyamine metabolic phenotype. The divergent metabolic and immune responses to ETEC challenge underscore the distinct strategies employed by these two breeds in maintaining gut homeostasis. These findings provide preliminary insights that may inform future breeding strategies aimed at enhancing intestinal health and disease resistance in pigs, pending validation in broader genetic backgrounds and mechanistic studies. Full article

Agmatinase (SpeB) catalyzes the hydrolysis of agmatine to produce putrescine, a key step in bacterial polyamine biosynthesis. Here, we report the crystal structure of SpeB from Klebsiella pneumoniae (kpSpeB) and characterize its oligomeric and active-site architecture. SEC–MALS analysis demonstrates that kpSpeB forms a canonical hexamer in solution. Structural comparison reveals high similarity to Escherichia coli SpeB and other members of the arginase superfamily, including proclavaminic acid amidino hydrolase (PAH) and guanidine hydrolase (GdmH). Despite strong conservation of residues coordinating the binuclear Mn²⁺ center, subtle differences in metal positioning and cavity geometry were observed. Surface analysis indicates variations in active-site cavity volume among homologues, with partial occlusion in GdmH due to a bulky tryptophan residue. These findings suggest that minor adjustments in metal coordination and cavity architecture may fine-tune substrate selectivity while preserving the conserved catalytic framework of the arginase superfamily. Full article

Salinity is a critical environmental stressor that inhibits seed germination and seedling growth globally. This study aimed to determine the optimal priming conditions for hot pepper (Capsicum annuum L.) seeds to alleviate salt stress-induced germination and growth reductions. Priming treatments included hydro-priming, chemical-priming (24-epibrassinolide (EBL), sodium nitroprusside (SNP), and polyamines), halo-priming (KNO₃), and modified drum-priming. Following treatment, germination characteristics, total polyphenol content (TPC), ABTS⁺ radical scavenging activity, and seedling growth traits were evaluated under 100 mM NaCl stress. Optimal conditions were identified as hydro-priming (50 h), chemical-priming (10⁻⁶ M EBL, 10⁻⁴ M SNP, 50 mM putrescine), halo-priming (300 mM KNO₃), and drum-priming (20 h hydration and 60 h incubation). Although NaCl treatment significantly reduced all germination traits, priming effectively mitigated these declines. A modified drum-priming method resulted in the shortest mean germination time (MGT) of 4.0 days, the highest germination rate (GR) of 25.2%·day⁻¹, and a 94% healthy seedling percentage (HSP), whereas the results for the untreated control were recorded as 6.6 days, 15.2%·day⁻¹, and 66%, respectively, under stress conditions. EBL and drum-priming showed the highest TPC and ABTS⁺ radical scavenging activity. Furthermore, priming prevented salt-induced reductions in seedling growth. EBL and drum-priming treatments resulted in the highest vitality index (VI). These results indicate that drum-priming and EBL priming are highly effective strategies for enhancing salt tolerance and ensuring uniform stand establishment in pepper seeds. Full article

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

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

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