Search Results (3,364)

Gum arabic (GA)-based edible coatings enriched with natural bioactive compounds offer a promising strategy for reducing postharvest losses and maintaining fruit quality. This study evaluated the effectiveness of GA coatings supplemented with carvacrol or caffeine in preserving the physicochemical quality, antioxidant status, and marketability of ‘Murcott’ mandarins during cold storage (5 ± 1 °C, 90–95% RH) for 60 days followed by 4 days of shelf life. Fruits were treated with distilled water (control), GA (10%), GA + imazalil (2000 ppm), GA + carvacrol (200 ppm), and GA + caffeine (200 ppm). Key quality parameters, including weight loss, decay incidence, firmness, electrolyte leakage, malondialdehyde (MDA), total soluble solids, titratable acidity, ascorbic acid, total phenolics, total flavonoids, and antioxidant enzyme activities of catalase (CAT) and peroxidase (POX), were evaluated. The results demonstrated that GA-based coatings, particularly GA + carvacrol, significantly reduced weight loss and decay while maintaining firmness and visual quality compared to the control. Coated fruits exhibited lower electrolyte leakage and MDA levels, indicating improved membrane integrity and reduced lipid peroxidation. In addition, the treatments enhanced antioxidant capacity, as reflected by increased phenolic and flavonoid contents and higher CAT and POX activities. Multivariate analysis further confirmed the strong association between coating treatments and improved quality attributes. In conclusion, GA coatings enriched with carvacrol or caffeine effectively improved postharvest quality and extended the shelf life of ‘Murcott’ mandarins, highlighting their potential as safe and eco-friendly alternatives to conventional postharvest treatments. Full article

Tyrosyl-DNA phosphodiesterase 1 (TDP1) is a key enzyme for the repair of stalled topoi-somerase 1 (TOP1)-DNA complexes. We have previously developed a TDP1 inhibitor, compound OL9-116, which is capable of enhancing the action of the anticancer drug topotecan (TPC), a TOP1 poison, in vitro and in vivo. In this study, the inhibition mode of OL9-116 (uncompetitive) was investigated. We have shown that N-terminal domain of TDP1, which is important for the cell function of TDP1 but is not involved in catalysis directly, reduced the inhibitory potency of OL9-116 probably by influencing the conformation of the enzyme. OL9-116 did not reduce cell viability and did not affect mitochondrial membrane potential. OL9-116 enhanced the cytotoxic/antiproliferative effect of TPC on the panel of tumor cells. This effect was not observed on nontumor cells or TDP1-deficient cells. OL9-116 and TPC had different effects on TDP1 and TOP1 gene expression detected by PCR depending on the cell type and the presence of functional TDP1. The direct relation between the effects of the compounds on the gene expression and cell survival was not found. The obtained data indicated a synergistic effect of OL9-116 and TPC, which appeared to be mediated by TDP1 inhibition rather than by an effect on TDP1 gene expression. Full article

Capsicum annuum is a Solanaceae crop that is sensitive to cold, which affects its growth and development upon prolonged exposure and ultimately reduces yield. In response, a complex regulatory network of cold-responsive genes is activated. Earlier studies have shown that SnRKs play a positive role in enhancing cold tolerance in different crops, including peppers; however, the underlying molecular mechanisms and downstream targets have yet to be fully elucidated. In this study, yeast hybrid screening using CaSnRK2.4 identified a potential interacting partner CaPDX1. The interaction between CaPDX1 and CaSnRK2.4 was further confirmed through Y2H, luciferase complementation, and bimolecular fluorescence complementation assays. Subcellular localization showed that CaPDX1 and CaSnRK2.4 are localized in the nucleus as well as in the cell membrane. Silencing of CaPDX1 through VIGS showed increased susceptibility of peppers to cold stress, negatively influenced antioxidant enzymatic activities, and increased relative electrolyte leakage and malondialdehyde levels. Conversely, transient overexpression of CaPDX1 in peppers enhanced cold tolerance by reducing the accumulation of REL and MDA. Ectopic expression of CaPDX1 in Arabidopsis thaliana significantly improved its cold tolerance, accompanied by enhanced activity of antioxidant enzymes and increased chlorophyll content. In summary, these results indicate that CaPDX1 is a positive regulator of cold tolerance in pepper, and its mechanism of action involves interaction with CaSnRK2.4 and the regulation of physiological and molecular responses in pepper under cold stress. Full article

Drought stress critically impacts plant growth and productivity. The bZIP transcription factor family is crucial for abiotic stress responses, yet its role in larch drought tolerance remains unclear. This study identified 19 bZIP genes in Larix kaempferi (Lamb.) Carr. and characterized LkbZIP4. Bioinformatics analysis classified it into the A subgroup. Subcellular localization and yeast two-hybrid assays confirmed that it is a nucleus-localized transactivator. Expression pattern analysis revealed that LkbZIP4 was highly specifically expressed in roots and was significantly induced by drought stress. A series of transgenic overexpression lines was successfully established through Agrobacterium tumefaciens-mediated method, using embryogenic callus of hybrid larch (L. kaempferi × L. gmelinii). Under 7% PEG-induced drought stress, LkbZIP4-overexpressing transgenic calli displayed enhanced drought tolerance relative to wild-type. This was evidenced by better growth, higher biomass, and reduced membrane damage, indicated by lower malondialdehyde content and relative electrolyte leakage. Meanwhile, these transgenic calli accumulated higher levels of osmoregulatory substances, including proline and soluble sugars, along with enhanced activities of antioxidant enzymes including superoxide dismutase and peroxidase. Our results indicate that LkbZIP4 functions to promote drought tolerance in larch, likely through the enhancement of osmotic adjustment and oxidative defense mechanisms. Full article

Drought stress significantly constrains crop productivity and yield stability. Sorghum (Sorghum bicolor L. Moench), a C4 cereal widely cultivated in arid and semi-arid regions, exhibits high water-use efficiency and remarkable drought tolerance. Understanding both the impacts of drought and the plant’s response mechanisms is essential for enhancing drought resilience in this crop. In this study, physiological changes and differential protein accumulation were analyzed in leaves of the sorghum inbred line BT × 623 under 10% PEG-6000-induced drought stress. The physiological adaptation to drought was characterized by improved water retention and mitigation of oxidative damage through the synergistic action of antioxidant enzymes. Using two-dimensional electrophoresis (2-DE) and MALDI-TOF-TOF mass spectrometry, 43 protein spots were successfully identified, corresponding to 38 unique proteins differentially expressed under osmotic stress. These proteins function in diverse biological processes, including protein synthesis, processing, and degradation; photosynthesis; carbohydrate and energy metabolism; transcriptional regulation; stress and defense; lipid and membrane metabolism; and amino acid metabolism. Proteomic profiling revealed that the coordinated modulation of multiple functional groups, such as those involved in photosynthesis, energy metabolism, transcriptional adjustment, ROS scavenging, and protein turnover, underpins sorghum’s osmotic stress adaptation. These findings provide key insights into the drought resistance mechanisms of sorghum at both physiological and proteomic levels. Full article

To address cryodamage in Culter alburnus sperm, this study evaluated the effects of trehalose supplementation in a conventional cryomedium (D-15 + 10% ethylene glycol). Six experimental groups were established: fresh sperm (G1), a conventional cryomedium (G2), groups supplemented with 10, 100, or 200 mmol/L trehalose (G3–G5), and a control group with extender only (G6). The group with 100 mmol/L trehalose (G4) was associated with improved post-thaw motility parameters (activation rate, movement time, and lifespan) and higher antioxidant (superoxide dismutase and catalase) and energy metabolism (ATPase, succinate dehydrogenase, lactate dehydrogenase) enzyme activities. Ultrastructural damage in G4 included partial plasma membrane rupture and mitochondrial swelling, while G6 exhibited additional damage features including membrane disintegration, mitochondrial disruption, and flagellar fracture. Proteomic analysis revealed that, compared to G1, G4 exhibited higher abundance of proteins (e.g., Histone H2A, cytochrome c oxidase, profilin) involved in structural integrity and energy homeostasis, whereas G6 showed signatures of oxidative stress and metabolic dysfunction (lower abundance of NADH dehydrogenase and higher abundance of calcium-transporting ATPase and glutathione S-transferase). In conclusion, 100 mmol/L trehalose was associated with improved cryopreservation outcomes, and the proteins identified provide a basis for further investigation. This approach offers a framework for refining germplasm conservation strategies in aquaculture. Full article

Cadmium (Cd) contamination is widely recognized as a major risk factor affecting the security and quality of crop production. Watermelon (Citrullus lanatus) is a globally cultivated fruit that is susceptible to Cd stress. 24-Epibrassinolide (EBR), an active brassinosteroid, is essential for plant growth and abiotic stress responses. However, its protective role in watermelon under Cd stress remains unclear. This study elucidates the physiological and molecular processes underlying EBR-mediated alleviation of Cd toxicity in watermelon seedlings. The results showed that exogenous EBR application effectively mitigated Cd-induced growth inhibition through decreased Cd deposition, reduced the accumulation of reactive oxygen species (ROS), lowered membrane lipid peroxidation, and increased antioxidant capacity in watermelon leaves under Cd treatment. Transcriptome (RNA-Seq) analysis revealed that EBR triggered substantial reprogramming of gene expression patterns, identifying 530 differentially expressed genes (DEGs) in Cd + EBR co-treatment compared with Cd treatment alone, including 204 down-regulated genes and 326 up-regulated genes. These DEGs are vital for controlling several physiological processes, including phenylpropane metabolism, phenylpropanoid biosynthesis, endoplasmic reticulum’s protein production, cell wall organization, and others. Further physiological assays confirmed that EBR increased the activities of PAL and 4CL, the core enzymes driving phenylpropanoid biosynthesis, leading to a significant accumulation of total phenols and flavonoids. Together, the above results give concrete proof of the powerful functions of 24-EBR, acting as an enhancer of plant performance under Cd stress by enhancing the antioxidant system and by activating the phenylpropanoid pathway and its derived metabolic networks. Full article

Chronic oxidative stress and lipid imbalance drive metabolic disorders such as obesity and non-alcoholic fatty liver disease, yet few therapies target the upstream redox imbalance in key tissues. Human carbonic anhydrase III (hCA III), a redox-associated enzyme enriched in liver and adipose tissue, has long remained pharmacologically elusive due to its low catalytic activity and lack of modulators. Here, we identify fragment-like nicotinic acid derivatives as non-sulfonamide hCA III modulators and evaluate their associated cellular effects. Using an esterase activity assay, we screened 25 analogues and identified two fragment-like hits, compound 17 (2-thioethyl) and compound 22 (6-morpholino), with IC₅₀ values of 487 and 361 µM, respectively. Orthogonal thermal shift analysis supported compound-protein interaction, and selected hits were subsequently evaluated in HepG2 cells. Both compounds were associated with reduced CA3 mRNA expression after treatment at 1 µM, while their cellular phenotypes diverged, with compound 22 increasing ROS under oxidative stress conditions and compound 17 affecting mitochondrial membrane potential. Taken together, these findings identify tractable nicotinic acid-derived fragment hits and associated cellular phenotypes that warrant further mechanistic investigation. These fragment-like hits provide a practical starting point for studying the redox-linked biology of hCA III. Full article

Background: Information on the autopolyploid of Gossypium herbaceum remains limited until now. Previously, the autotetraploid of G. herbaceum was successfully generated via colchicine-induced chromosome doubling from the diploid cultivar ‘Hongxing’ in our lab. Methods: To investigate the drought stress response mechanism of this tetraploid, the autotetraploid S4 was used as the experimental material. The plants were subjected to drought stress during the flowering stage, followed by measurements of physiological and biochemical indicators and transcriptomic sequencing analysis. Results: Under drought stress, MDA content increased, and cell membranes sustained oxidative damage. Photosynthetic parameters, such as net photosynthetic rate (Pn), were significantly suppressed, while the activity of osmotic regulators and key antioxidant enzymes increased significantly. After rehydration, all of the above physiological indicators showed varying degrees of recovery. Transcriptome analysis revealed that, when comparing the treatment group with the control group, a total of 5530 differentially expressed genes (DEGs) were identified, with 2714 up-regulated and 2816 down-regulated. Furthermore, this study investigated the drought resistance mechanism involving the interaction between the MAPK signaling pathway and other metabolic pathways in the autotetraploid. Nine drought-resistant genes, including MAPK3, bHLH47, GaRbohD, RIBA1, PIP1-3, RCA1, RbohD, CYP707A and HSP70, were selected and analyzed using real-time quantitative PCR; the results were generally consistent with the transcriptomic data. Conclusions: These findings substantially enhance our understanding of the molecular mechanisms underlying drought responses in autotetraploids. This novel autotetraploid genotype expands the available cotton germplasm resources and is expected to hold significant value for research on polyploidy evolution. Full article

The ripe fruits of blackcurrant (Ribes nigrum L.) are rich in vitamin C, anthocyanins, and flavonoids. Besides being consumed fresh, the fruits can be processed into fruit juices, jams, wines, and other products, exhibiting considerable economic and nutritional value. Flavonoids are a class of important plant secondary metabolites with antioxidant, anti-inflammatory, and anti-cancer properties. Although previous studies have confirmed the involvement of multiple structural genes and transcription factors in flavonoid biosynthesis, the specific role of the dihydroflavonol 4-reductase (DFR) gene in regulating flavonoid accumulation during fruit development of blackcurrant remains to be clearly elucidated. In this study, we identified an RnDFR gene located in the nucleus and cytoplasm, which has the same expression trend as flavonoid content in fruit development stages. Overexpression of RnDFR improved the flavonoid accumulation and upregulated the expression levels of related structural genes (4CL, CHS, LDOX, ANR, and UFGT) in tomato. Transiently overexpressing RnDFR in blackcurrant fruit also increased the content of flavonoids and DFR enzyme activity, whereas silencing RnDFR resulted in the opposite effect. In addition, overexpression of RnDFR in tomato seedlings improved cold and drought tolerance by increasing flavonoid accumulation, reducing membrane lipid peroxidation damage and enhancing the activities of antioxidant enzymes. This study systematically reveals the key role of RnDFR in flavonoid biosynthesis and the enhancement of cold and drought tolerance, and offers an important theoretical basis for future efforts to optimize flavonoid content in blackcurrant and improve fruit nutritional quality. Full article

Oxidative stress generates oxidized phospholipids (OxPLs) that alter membrane structure and inflammatory lipid signaling, yet the underlying biophysical mechanisms remain poorly understood. Here, we examine how two structurally distinct truncated oxidized phosphatidylcholines (OxPCs), 1-palmitoyl-2-(5′-oxo-valeroyl)-sn-glycero-3-phosphocholine (POVPC) and 1-palmitoyl-2-glutaryl-sn-glycero-3-phosphocholine (PGPC), remodel membrane lateral organization and regulate secretory phospholipase A₂ (sPLA₂) activity. Large unilamellar vesicles composed of sphingomyelin, cholesterol, and either monounsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or polyunsaturated 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PDPC) were used to reconstitute the liquid-ordered/liquid-disordered (L_o/L_d) phase coexistence characteristic of eukaryotic plasma membranes. Fluorescence spectroscopy revealed that OxPLs modulate lipid packing and nanodomain organization in a structure- and composition-dependent manner. POVPC promoted pronounced membrane ordering and L_o domain stabilization compared with PGPC, particularly in monounsaturated membranes with low cholesterol content. In contrast, PDPC-containing membranes, especially at elevated cholesterol, exhibited enhanced structural resilience to OxPL-induced perturbations. These biophysical changes were associated with distinct functional outcomes. Notably, the relationship between membrane structural parameters and sPLA₂ activity was not linear, indicating a decoupling between bulk membrane properties and enzymatic response. sPLA₂ activity was linked to membrane lateral organization: the size of L_o domains modulate hydrolysis by influencing the physicochemical properties of L_o/L_d interfaces, which may represent preferential sites for enzyme activation. Consistent with this, POVPC reduced sPLA₂ activity through stabilization of ordered domains at both low and high cholesterol, while PGPC enhanced hydrolysis at high cholesterol. Importantly, PDPC-containing membranes attenuated sPLA₂ activity and exhibited a protective effect against OxPC-induced enzymatic activation. Together, these findings identify membrane lateral organization as a key regulator of sPLA₂ function and provide mechanistic insight into how oxidative stress can differentially modulate inflammatory lipid signaling depending on membrane composition. This work highlights membrane organization as an active determinant of enzyme activity and a potential target in pathologies associated with oxidative stress, including atherosclerosis, neuroinflammation, and metabolic disease. Full article

Theaflavin-3,3′-digallate (TF3), a flavan-3-ol derivative found in black tea, exhibits anti-tumor activity, but its mechanism of action in hepatocellular carcinoma (HCC) remains to be elucidated. Here we systematically delineate how TF3 targets Pin1 to suppress HCC through an integrated approach combining computational simulations, enzyme assay and cell-based assays. TF3 spontaneously occupies the active site of Pin1 with a docking score of −8.9 kcal/mol, inhibiting its PPIase activity (IC₅₀ = 60.33 μmol/L) and yielding a binding constant (K_a) of 3.1 × 10⁵ mol/L. Drug affinity responsive target stability (DARTS) assays further corroborated that TF3 directly engages Pin1 within HCC cells. Functionally, TF3 potently suppressed the viability of HepG2, SK-Hep-1 and Huh-7 cells in both dose- and time-dependent manners (IC₅₀ = 61.22, 14.09 and 69.85 μmol/L at 24 h, respectively), and exhibited a modest selectivity window against the viability of L02 and THLE-2 cells (IC₅₀ = 133.43 and 90.29 μmol/L at 24 h, respectively). In addition, TF3 triggers mitochondrial-mediated apoptosis, evidenced by ROS accumulation, loss of mitochondrial membrane potential, an elevated Bax/Bcl-2 ratio, cytochrome c release and enhanced PARP cleavage, and induces G₂/M phase arrest. It also robustly inhibits HCC cell proliferation, invasion and migration, coinciding with downregulation of proteins governing cell cycle progression and invasive behavior. Transcriptome profiling coupled with enrichment analysis discovered that TF3 treatment differentially regulated 5009 genes, which were prominently enriched in pathways linked to apoptosis, cell cycle control, MAPK and PI3K/AKT signaling pathways. Western blotting analysis revealed that TF3 selectively suppresses phosphorylation of p38 and the PI3K/AKT cascade, activating JNK phosphorylation. In summary, our findings indicate that TF3 suppresses HCC proliferation by targeting Pin1, with attendant modulation of the MAPK and PI3K/AKT pathways, thereby presenting a potential candidate for targeted HCC therapy. Full article

Polyamines are small, positively charged molecules essential for fundamental cellular processes, including transcription, translation, and membrane fluidity. In the central nervous system (CNS), these molecules serve as homeostatic gatekeepers by modulating neuroreceptors like NMDA and supporting autophagic clearance. While basal polyamine levels are necessary for proper neuronal differentiation and memory formation, their dysregulation is a hallmark of neurodegenerative pathologies such as Alzheimer’s and Parkinson’s diseases. Neurotropic viruses, including poliovirus, Zika virus, and human cytomegalovirus are significant human pathogens that rely on cellular metabolites for their replication, including polyamines. These pathogens exploit polyamines at multiple stages of their life cycles, relying on them for virion stability, cellular attachment, and the stimulation of viral enzyme activity. Notably, diverse viral families share this dependence, making polyamine biosynthesis a prime target for broad-spectrum antiviral therapies. This review covers the current understanding of polyamine metabolism in virus infection and CNS health and disease, as well as considering antiviral therapies targeting host polyamines to limit neurotropic virus infection. Full article

Larix olgensis, a keystone timber species in Northeast China, is increasingly threatened by Neofusicoccum laricinum-induced shoot blight, a devastating disease that compromises forest health and necessitates sustainable management strategies. Here, we demonstrate that the endophytic bacterium Bacillus amyloliquefaciens JL54 elicits multifaceted defense responses in L. olgensis, enhancing resistance to pathogen infection. Greenhouse assays revealed that JL54 pretreatment reduced disease incidence by 12.5% and achieved 43.75% control efficacy while maintaining host vigor. Histochemical analyses identified JL54-induced rapid hydrogen peroxide (H₂O₂) accumulation, extensive lignin deposition, and localized programmed cell death (PCD), indicative of a primed immune response. Transcriptomic analyses uncovered distinct temporal defense patterns: early-stage responses (0 h post-inoculation) were characterized by upregulation of cutin, suberin, and wax biosynthesis pathways, reinforcing physical barriers, whereas late-stage responses (12 h post-inoculation) were dominated by ribosome- and proteostasis-related pathways (e.g., heat shock proteins [HSPs], glutathione S-transferases [GSTs]) to mitigate cellular damage. Biochemical assays corroborated these findings, with JL54 colonization reducing membrane lipid peroxidation (27.2% decrease in malondialdehyde content) and significantly elevating the activity of key defense enzymes, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), and GST. Phytohormone profiling implicated jasmonic acid (JA) as the central mediator of induced systemic resistance (ISR), with JL54-potentiated JA signaling preceding pathogen containment. Collectively, these results demonstrate that JL54 contributes to a coordinated defense strategy in L. olgensis, integrating structural reinforcement (cuticle/lignin), oxidative stress management, and JA-mediated immune priming. These insights advance the understanding of endophyte-conferred resistance in conifers and highlight JL54’s potential as a biocontrol agent for sustainable forestry. Full article

Pseudomonas plecoglossicida causes bacterial hemorrhagic ascites in ayu (Plecoglossus altivelis), a lethal disease characterized by abdominal distension with hemorrhagic ascites, multifocal organ hemorrhages, and histopathologically evident hepatocellular necrosis and inflammatory infiltration. The lack of effective treatments exacerbates mass mortalities, posing a significant threat to aquaculture. Given the severe pathogenesis of P. plecoglossicida infection—which involves bacterial colonization, tissue necrosis, and host immune dysregulation—effective therapeutic strategies are urgently needed. Through a screen of traditional Chinese medicine monomers, we identified harmine, an indole alkaloid derived from Peganum harmala seeds, as a potent agent against this pathogen. In vivo, harmine exhibited direct bactericidal activity by disrupting membrane integrity, as evidenced by increasing membrane permeability, and inhibiting biofilm formation. In an ayu infection model, harmine significantly increased host survival, reduced tissue bacterial load, and enhanced innate immunity by augmenting monocyte/macrophage phagocytosis and bactericidal capacity while suppressing pro-inflammatory cytokine release and apoptosis. Mechanistically, the Drug Affinity Responsive Target Stability assay was used to identify the molecular target of harmine, followed by functional validation through PRDX6−knockdown experiments. Harmine exhibited direct bactericidal activity by disrupting membrane integrity and inhibiting biofilm formation. In the ayu infection model, harmine significantly increased host survival, reduced tissue bacteria1 load, and enhanced innate immunity by augmenting monocyte/macrophage system and bactericidal capacity while suppressing pro-inflammatory cytokine release and apoptosis, the latter likely through modulation of PRDX6−mediated oxidative stress and downstream caspase signaling. Mechanistically, DARTS revealed that harmine binds to peroxiredoxin 6 (PRDX6), a multifunctional enzyme possessing peroxidase, phospholipase A₂, and lysophosphatidylcholine acyltransferase activities. This binding liberates TNF receptor-associated factor 6 (TRAF6), facilitating its mitochondrial translocation and association with the ECSIT signaling integrator complex, thereby amplifying mitochondrial reactive oxygen species (mROS) production and potentiating macrophage-mediated bacterial killing. These findings establish harmine as a promising therapeutic candidate for controlling P. plecoglossicida infections and underscore the value of host-directed immunomodulation derived from natural products in aquaculture medicine. Full article