Search Results (28,245)

Background/Objectives: The efficacy of inactivated foot-and-mouth disease virus (FMDV) vaccines depends on the structural integrity of the 146S virions. However, instability of 146S antigens during vaccine manufacturing and storage can compromise vaccine quality. Despite its high immunogenicity, the Korean serotype O strain O Jincheon (O JC) exhibits poor physical stability. Methods: To enhance antigenic stability while preserving strain-specific antigenicity, we engineered a VP1-substituted recombinant virus, (R) O1 M–O JC_VP1, by integrating the VP1 coding region of O JC into the O1 Manisa (O1 M) backbone. Results: The resulting chimeric virus exhibited significantly improved capsid stability, as demonstrated by an increased melting temperature and enhanced resistance to thermal stress, chloroform exposure, and long-term storage. Importantly, the recombinant antigen maintained its immunogenicity and induced antibody responses comparable to those induced by the parental O JC strain in vaccinated pigs. Conclusions: These findings demonstrate that VP1-direct chimeric engineering can improve capsid stability without compromising antigenicity and provide a practical approach for developing a stable FMDV vaccine. Full article

Fibrin gel, a protein-based polymer naturally generated during coagulation, has garnered attention in the biomedical field for applications such as fibrin glue, due to its specific physical and biological properties. Despite it, low mechanical strength and rapid degradation limited its utilization for biomedical applications. This study presents a reproducible protocol for the synthesis of pure fibrin hydrogels, aimed at achieving predictable structural properties through the precise calibration of fibrinogen and thrombin concentrations. By examining the mechanical and morphological characteristics, as well as the relationship between reagent concentrations and structural integrity, this research assesses impacts on swelling behavior, water absorption, and overall stability. Through a comprehensive analytical approach, we identified an optimal formulation, specifically 2.25 mg/mL fibrinogen and 1.375 U/mL thrombin, that effectively balances structural integrity with high cytocompatibility. The results demonstrate that this calibrated approach ensures high procedural reproducibility and a well-defined hydrogel architecture without the need for exogenous chemical cross-linkers. This work provides a robust methodological framework to overcome the common lack of reproducibility in fibrin-based hydrogel studies, positioning these materials as highly reliable candidates for advanced 3D in vitro models and biomedical applications. Full article

Background/Objectives: Radial extracorporeal shock wave therapy (rESWT) is used to treat neuromuscular disorders such as spasticity, but the mechanisms by which rESWT modulates muscle tone remain incompletely understood. One proposed mechanism involves mechanical perturbation of the neuromuscular junction (NMJ), particularly destabilization of acetylcholine receptor (AChR) clusters in the postsynaptic membrane. Because rapsyn knockout mice are not viable, Caenorhabditis elegans (C. elegans) provides an alternative model for studying neuromuscular signaling, expressing the rapsyn homolog RPY-1, a postsynaptic scaffolding protein involved in AChR organization at the NMJ. This study examined whether loss of RPY-1 alters locomotor responses of C. elegans to radial extracorporeal shock wave (rESW) exposure. Methods: Wild-type worms and rpy-1 knockout worms (rpy-1-KOs) were exposed to defined numbers of rESWs. Locomotor behavior was quantified using automated tracking of parameters describing speed, trajectory and body-wave dynamics. Behavioral responses were analyzed both as absolute values and relative to genotype-specific baseline values. Results: rESW exposure produced pronounced alterations in locomotor behavior across all parameters analyzed. Absolute values revealed baseline differences between genotypes. After normalization to genotype-specific baseline values, wild-type worms and rpy-1-KOs responded similarly to moderate exposure levels. At higher exposure levels, genotype-dependent differences became more apparent. Locomotor impairment was most pronounced immediately after exposure but improved during the subsequent recovery period of three hours. Conclusions: rESWs induced strong but largely reversible locomotor alterations in C. elegans during the first hours after exposure. Loss of the rapsyn homolog RPY-1 modified these responses, particularly at higher exposure levels. These findings indicate that RPY-1 influences behavioral responses to rESW exposure, while direct effects on NMJ structure or AChR organization cannot be determined from the present data. Full article

Protein turnover and extracellular proteolysis continuously generate diverse peptide fragments within biological systems, yet the metabolic and pharmacological implications of these peptides remain incompletely understood. Among these transporters, members of the solute carrier family 15 (SLC15), including peptide transporter 1 (PEPT1/SLC15A1) and peptide transporter 2 (PEPT2/SLC15A2), mediate the proton-coupled uptake of dipeptides, tripeptides, and structurally related compounds across cellular membranes. While these transporters have been extensively studied in the context of intestinal peptide absorption and drug delivery, their potential roles in cancer biology remain incompletely understood. Tumor microenvironments are characterized by extensive proteolysis and dynamic metabolic remodeling, processes that can generate diverse peptide fragments derived from extracellular matrix proteins and intracellular protein turnover. These peptides may accumulate locally and potentially serve as substrates for cellular peptide transport systems. Once internalized through peptide transporters, dipeptides are typically hydrolyzed into free amino acids that can support biosynthetic pathways, energy metabolism, and cellular growth. In addition to their potential metabolic roles, certain endogenous dipeptides have also been reported to influence cellular signaling pathways and redox homeostasis. The broad substrate specificity of peptide transporters has also attracted significant interest in pharmacology because numerous clinically used drugs exploit these transport systems for efficient cellular uptake. This property raises the possibility that peptide transporters may be utilized for transporter-mediated drug delivery strategies, including the development of peptide-modified prodrugs or dipeptide–drug conjugates. In this review, we summarize the molecular characteristics and physiological functions of dipeptide transport systems with a particular focus on the SLC15 transporter family. We then discuss emerging evidence linking peptide transporters to tumor metabolism and the tumor microenvironment. Finally, we highlight current progress and future perspectives in exploiting peptide transport systems for transporter-mediated drug delivery and therapeutic targeting in cancer. Full article

Ferroptosis of mesenchymal stem cells (MSCs) is a critical bottleneck restricting the efficiency of ruminant biological breeding. Phloretin, a natural bioactive polyphenol, exhibits potential ferroptosis-inhibitory activity. However, the regulatory effects and underlying mechanisms of phloretin on ruminant MSCs remain poorly understood. This study aimed to investigate the effects of phloretin on ferroptosis and elucidate its underlying molecular mechanisms. Herein, we isolated and cultured adipose-derived mesenchymal stem cells (AD-MSCs) from adipose tissue of a 9-day-old Leizhou goat and established a ferroptosis model in these cells using RSL3. We detected cell viability, proliferation, migration, ferroptosis-related indexes and key protein expression. The results showed that phloretin (25 and 50 μM) dose-dependently inhibited ferroptosis in goat AD-MSCs, reducing intracellular ferrous ion (Fe²⁺), reactive oxygen species (ROS) and lipid peroxidation levels, restoring glutathione content, and ameliorating mitochondrial structural damage. Mechanistically, phloretin exerted its anti-ferroptosis effects through direct antioxidant activity, activation of the Nrf2/HO-1/GPX4 signaling pathway and Fe²⁺ chelation. Nrf2 and GPX4 were key targets in this process. These results provide preliminary in vitro evidence and a theoretical basis for the potential application of phloretin in future research related to meat goat production and ruminant breeding. Full article

Three new, previously undescribed tanzawaic acids, steckwaic acids H–J (1–3), and twenty-three known natural products (4–26) were isolated from the marine algicolous fungus Penicillium steckii SCSIO 41040. Structurally, compound 3 underwent a rare hydration reaction at the double bond of its carboxylic acid side chain. The chemical structures and stereochemistry were determined using comprehensive spectroscopic analyses, including NMR, electronic circular dichroism (ECD) calculations, and high-resolution electrospray ionization mass spectrometry (HRESIMS), and verified by literature comparison. The protective effect of tanzawaic acids on inflammatory damage to the intestinal epithelial barrier was assessed using an LPS-stimulated Caco-2/THP-1 co-culture model. Notably, immunofluorescence and Western blotting assays showed that compound 10 significantly enhanced the fluorescence signals and protein expression of ZO-1 and occludin, alleviated lipopolysaccharide (LPS)-induced intestinal barrier damage in Caco-2 cells, and contributed to the re-establishment of intestinal barrier homeostasis. Our findings demonstrate the critical role of tanzawaic acids in maintaining intestinal barrier integrity, identifying them as promising lead compounds for UC treatment. Full article

Background: This study investigated the mechanisms underlying diarrhea induced by a high-fat diet (HFD) under a state of fatigue, focusing on gut microbiota dysbiosis, bile acid metabolic disturbance, and gut–liver injury. Methods: Mice were assigned to a normal control diet (NCD) group, a HFD-induced diarrhea under fatigue (HFDM) group, and a HFD-induced diarrhea with aggravated dysbiosis (HFDMA) group. Histopathology, inflammatory factors, intestinal barrier-related proteins, small-intestinal microbiota, and colonic bile acid profiles were assessed, and correlation analyses were performed among gut microbiota, bile acids, and inflammatory factors. Results: Compared with the NCD group, both the HFDM and HFDMA groups showed diarrhea-like and fatigue-like phenotypes, histopathological injury in the small intestine and liver, increased tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels, and impaired intestinal barrier function. No significant differences in inflammatory factors were observed between the HFDM and HFDMA groups. Zonula occludens-1 (ZO-1) expression decreased in both model groups but reached statistical significance only in the HFDMA group, whereas Claudin-1 expression was significantly reduced in both groups. Gut microbiota analysis showed altered community structure, with downward trends in alpha diversity that did not reach statistical significance but clear separation trends in beta diversity. Proteobacteria and Streptococcus increased, whereas Ligilactobacillus decreased. Total bile acid levels did not differ significantly among groups; however, the ratio of secondary to primary bile acids was significantly reduced in both model groups, particularly in the HFDMA group, with decreases in representative secondary bile acids, including hyodeoxycholic acid (HDCA) and isolithocholic acid (isoLCA). Correlation analysis further supported close associations among gut microbial alteration, bile acid disturbance, and intestinal and hepatic inflammation. Conclusions: Gut microbiota dysbiosis may disrupt bile acid metabolism, impair intestinal barrier integrity, and promote intestinal and hepatic inflammatory responses, thereby contributing to diarrhea progression under fatigue and HFD conditions through the gut–liver axis. Full article

Tor sinensis is an emerging aquaculture species in China, yet the effect of dietary protein on its hepatic and intestinal health remains unexplored. This study evaluated the effects of five diets designed to be isoenergetic and isolipidic with graded protein levels (28% to 40%) on juvenile T. sinensis (initial weight: 10 ± 0.4 g) over 60 days. Growth performance improved with increasing protein up to 34%, beyond which it plateaued. Regression analysis indicates that the optimal dietary protein level for both weight gain and specific growth rate is 34.3%. Hepatic antioxidant enzyme activities (SOD and CAT) were highest in the 34% protein group, while triglyceride content was lowest. Histological examination revealed minimal hepatocyte swelling, nuclear displacement, and lipid droplet accumulation at this protein level. Intestinal trypsin activity and villus morphology (height, width, and muscular thickness) were also optimized at 34% protein, though lipase and amylase activities remained unaffected. These findings demonstrate that a 34% dietary protein level supports optimal growth, enhances liver antioxidant capacity, and improves intestinal structure and function in juvenile T. sinensis, providing critical insights for its formulated feed development. Full article

Background: Prostate cancer (PCa) is the leading male urinary malignancy globally. Our previous article demonstrated the anti-PCa activity of Euphorbia humifusa Willd water extract (EHW) and some of its compounds via downregulating AR expression, but the anti-PCa active compounds from Euphorbia humifusa Willd (EH) and their mechanisms of action are yet to be clarified. Thus, the current article studied the in vitro anti-PCa effects of 3,3′-di-O-methylellagic acid (3,3′-di-O-Me-EA) derived from EHW and the related mechanism involved. Methods: 3,3’-di-O-Me-EA was isolated from EHW applying bioassay-guided fractionation. The spectroscopic methods were used to determining the structure of 3,3′-di-O-Me-EA. The drug-likeness and ADMET properties (absorption, distribution, metabolism, excretion, and toxicity) of 3,3′-di-O-Me-EA were analyzed in silico. Molecular docking and real-time surface plasmon resonance (SPR) analysis were performed to measure the interaction of 3,3′-di-O-Me-EA and VDAC1 protein. The viability and apoptosis of 22RV-1 and DU145 PCa cells were determined using MTT and Annexin V-FITC staining assay, respectively. q-PCR and Western blot experiments were used to analyzing the gene and protein expressions of VDAC1. Results: 3,3′-di-O-Me-EA was isolated and purified from EHW with a purity of ≥90.06%, and its structure was identified by HRTOF mass, NMR, and an authentic standard. In silico ADMET analysis indicated its favorable drug-like and pharmacokinetic properties. Molecular docking and SPR results confirmed that 3,3′-di-O-Me-EA could bind with the VDAC1 protein. Moreover, 3,3′-di-O-Me-EA dose- and time-dependently inhibited 22RV-1 and DU145 PCa cell viability, and induced apoptosis in a dose-dependent manner (p < 0.05). RT-qPCR and Western blot results showed that 3,3′-di-O-Me-EA dose-dependently up-regulated VDAC1 gene and protein expression levels in 22RV-1 and DU145 cells (p < 0.05). Meanwhile, in VDAC1-depleted 22RV-1 and DU145 cells, 3,3′-di-O-Me-EA down-regulated VDAC1 gene and protein expression levels, increased cell viability, and inhibited apoptosis compared to 22RV-1 and DU145 cells (p < 0.05). Furthermore, 3,3′-di-O-Me-EA enhanced VDAC1 gene and protein expression levels, inhibited cell viability, and induced apoptosis in VDAC1-overexpressed 22RV-1 and DU145 cells compared with 22RV-1 and DU145 cells (p < 0.05). Overall, EH active compound 3,3′-di-O-Me-EA may inhibit viability and induce apoptosis of 22RV-1 and DU145 PCa cells via up-regulating VDAC1 gene and protein expression levels. Conclusion: The results indicated that the 22RV1 and DU145 PCa cell viability inhibitory effects of 3,3′-di-O-Me-EA isolated from EH may be mediated by induction of apoptosis through up-regulation of VDAC1 gene and protein expression levels. Full article

Milk is a complex biochemical mixture in which proteins significantly influence the behaviour of xenobiotics and bioactive compounds. Interactions between milk proteins and substances such as veterinary drugs or natural bioactives can modify molecular stability, binding dynamics, and exposure pathways, affecting food safety and the One Health concept. This study presents a comparative, matrix-focused investigation on how three chemically distinct ligand classes, sulfanilamide antibiotics, naturally occurring phenolic compounds and zinc–polyphenol complexes, interact with major milk proteins, β-lactoglobulin and casein. Protein–ligand interactions were examined using steady-state fluorescence spectroscopy to assess quenching behaviour and comparative interaction trends. Molecular docking was employed as a qualitative tool to provide structural context. Distinct interaction patterns were observed across ligand classes, reflecting differences in molecular structure, hydrophobicity, and coordination chemistry. Importantly, zinc coordination modified interaction profiles relative to the corresponding free ligands, indicating that metal coordination can affect ligand–protein interactions within the milk matrix. These findings support the concept that milk proteins may function as matrix-dependent modulators of ligand behaviour. The study is positioned as a hypothesis-generating framework highlighting the importance of food matrices as active biochemical environments. Herein, we provide a foundation for hypothesising how the milk matrix affects residue behaviour and bioactive interactions, with relevance to veterinary pharmacology and food safety risk assessment. Full article

A zinc complex of chelidonic acid (4-oxo-4H-pyran-2,6-dicarboxylic acid) was obtained by reaction with zinc oxide under isothermal conditions. Its composition was confirmed by elemental and thermogravimetric analyses, and its molecular structure was characterized using NMR and IR spectroscopy. Single-crystal X-ray diffraction revealed that the complex crystallizes as a one-dimensional coordination polymer, [ZnChel(H₂O)₄]_n, in the triclinic space group P-1, featuring a distorted octahedral Zn(II) center coordinated by two chelidonate ligands and four water molecules. This six-coordinate arrangement contrasts with previously described tetra-coordinated Zn–chelidonate complexes. Quantum-chemical calculations and molecular dynamics simulations indicated that, in aqueous solution, Zn(II) preferentially forms a monodentate ZnChel(H₂O)₅ species, consistent with the solid-state coordination environment. The interaction of the complex with bovine serum albumin (BSA) was examined by fluorescence, UV–Vis absorption, and circular dichroism spectroscopy, revealing a mixed static–dynamic quenching mechanism, moderate binding affinity, and hydrogen-bonding/van der Waals contributions accompanied by alterations in BSA secondary structure. These results expand the structural chemistry of chelidonic acid and provide biophysical insight into the protein-binding behavior of zinc chelidonate, supporting its potential relevance as a zinc-based bioactive compound. Full article

Walnut is an important nut with a rich nutritional profile and associated health benefits for the human body. B-box (BBX) proteins containing one or two BBX motifs play pivotal roles in plant growth and developmental processes; nevertheless, the functions of JrBBXs in walnut anthocyanin biosynthesis remain inadequately understood. In this study, 39 JrBBXs in red walnut ‘RW-1’ were identified, with phylogenetic analysis suggesting that they were divided into six classes based on the distribution of conserved domains and unevenly distributed on 14 chromosomes. Promoter analysis demonstrated that JrBBX promoters possessed an abundance of light responsiveness elements, ABA responsiveness elements, MYB binding sites and MYC binding sites. The transcriptome analysis results demonstrated that eight JrBBXs were differently expressed in normal green walnut ‘Zhonglin 1’ and red walnut ‘RW-1’ seed coats. Furthermore, qRT-PCR (quantitative real-time polymerase chain reaction) analysis showed that JrBBX3 exhibited lower expression during seed coat development in ‘RW-1’. Y1H (Yeast One-Hybrid) and LUC (dual-luciferase reporter) assays revealed that JrBBX3 directly inhibited the expression of JrUFGT5, considered a key anthocyanin biosynthesis structural gene in research. Subcellular localization analysis indicated both cytoplasmic and nuclear localization of JrBBX3. Transient overexpression of JrBBX3 in walnut leaves resulted in reduced JrUFGT5 expression and anthocyanin accumulation. Collectively, these findings revealed the negative regulation of JrBBX3 in red walnut anthocyanin biosynthesis, and provided a basis to further study the anthocyanin biosynthesis mechanism of red walnut. Full article

Psychrophilic organisms are able to grow at temperatures down to −15 °C, while hyperthermophiles can multiply at temperatures up to 122 °C. What structural changes in extremophile proteins are needed to maintain stable and biochemically active structures under such conditions? Understanding how such extremophiles accomplish this is relevant for human health, biotechnology, and our search for life elsewhere in the universe. The purpose of the current study is to report and compare the structures of four rubredoxins (Rds), the first ever two experimental psychrophile bacteria structures (from Gram-positive Clostridium psychrophilum and Gram-negative Polaromonas glacialis) and two hyperthermophiles from the Gram-negative Thermotoga maritima bacterium and the archaeon Pyrococcus yayanosii, also a piezophile, as part of a program to understand structural variations that support both stability and function under extreme conditions. These structures were obtained using synchrotron radiation X-ray diffraction at 100 K. All four structures had the expected overall rubredoxin fold. Rubredoxin from the only aerobic psychrophilic bacterium Polaromonas glacialis had larger variations in sequence and structure, whereas the other psychrophilic bacterium showed properties closely related to hyperthermophile rubredoxins. Multi-subunit structures showed similar RMSD variability independent from their thermal adaptation status. We propose including functional information in the analysis since temperature optimization may not be the only determinant for a specific protein adaptation. Full article

Mechanical stress has been implicated in retinal pigment epithelium (RPE) dysfunction and angiogenic signaling in retinal disorders; however, its direct in vivo effects on the RPE–choroid complex remain incompletely understood. Here, we established a mouse model of localized mechanical stress by subconjunctival implantation of glass beads (0.8–1.2 mm in diameter) in eight-week-old C57BL/6J mice to induce transscleral stretching of the RPE. Ocular tissues were analyzed two days after implantation using histological, immunohistochemical, and molecular approaches, and inflammatory mediators were quantified by multiplex cytokine assays. Mechanical stress induced focal serous retinal detachment, elongation of photoreceptor outer segments, and disruption of the RPE tight junction protein ZO-1. VEGF expression in the RPE–choroid complex was significantly upregulated and accompanied by increased levels of inflammatory mediators, including MCP-1. Intravitreal administration of anti-VEGF agents effectively suppressed stress-induced VEGF expression. These findings indicate that mechanical stress is sufficient to induce structural disruption and angiogenic signaling in the RPE in vivo, providing a useful experimental platform for investigating stress-related retinal responses and therapeutic modulation of VEGF signaling. Full article

Chronic Obstructive Pulmonary Disease (COPD) is characterized by persistent inflammation and structural alterations in the lung triggered mainly by oxidative stress. Colonization by the opportunistic fungus Pneumocystis has been associated with worse clinical outcomes in COPD, yet its role in airway remodeling remains unclear. To this end, an elastase-induced COPD model was established, followed by colonization with Pneumocystis. Lung tissue was analyzed histologically and molecularly to assess epithelial thickness, alveolar morphometric parameters (mean linear intercept [MLI], D₀, D₁, D₂), inflammation, collagen deposition, and the expression of remodeling and oxidative stress markers. Emphysematous damage parameters MLI, D₀, D₁, and D₂ were markedly elevated in co-exposed animals, indicating enhanced alveolar enlargement. Animals with COPD and Pneumocystis colonization showed a significant increase in airway inflammation compared with control, COPD, and Pneumocystis groups. Airway epithelial thickness, mucus metaplasia, and collagen deposition exhibited a summative increase in the COPD/Pneumocystis group. Redox-responsive markers, such as superoxide dismutase (SOD) and catalase, were upregulated. Moreover, protein and mRNA levels of nuclear factor erythroid 2–related factor 2 (Nrf2) and its downstream gene heme oxygenase-1 (Hmox1) were significantly increased, with the strongest activation observed in co-exposed animals. Integrative correlation analysis showed that Pneumocystis burden positively correlated with lung damage, inflammation, and epithelial remodeling. These structural alterations were accompanied by coordinated activation of the antioxidant pathway Nrf2. Taken together, Pneumocystis colonization is associated with enhanced pulmonary remodeling and modulation of antioxidant signaling in experimental COPD, promoting structural and molecular changes that may contribute to disease progression. These findings suggest that Pneumocystis acts as an amplifying factor in COPD-associated lung damage. Full article