International Journal of Biological Macromolecules最新文献

Carotenoids serve as key quality indicators in yellow peaches, and enhancing their content is crucial for improving overall fruit quality. In this study, yellow peaches were treated with 1 mM abscisic acid (ABA) or 0.5 mM fluridone (Flu), an ABA biosynthesis inhibitor. ABA treatment upregulated the expression of key carotenoid biosynthesis genes, including Phytoene Synthase (PpPSY), Phytoene Desaturase (PpPDS), Zeta-Carotene Desaturase (PpZDS), β-Carotene Hydroxylase (PpCHYB), Lycopene β-Cyclase (PpLCYB), and Zeaxanthin Epoxidase (PpZEP), while downregulating the carotenoid degradation-related gene 9-Cis-Epoxycarotenoid Dioxygenase 1 (PpNCED1). This coordinated regulation promoted zeaxanthin, lutein, β-cryptoxanthin, and β-carotene, leading to a significant increase in total carotenoid content. In contrast, Flu treatment produced opposite effects, suppressing carotenoid biosynthesis and accumulation. The negative regulatory role of the transcription factor PpZAT10 in carotenoid accumulation was confirmed through transient overexpression and virus-induced gene silencing (VIGS) in peach fruits, as well as transgenic overexpression and CRISPR/Cas9-mediated knockout in peach callus. Furthermore, yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and dual-luciferase assays demonstrated that PpZAT10 directly binds to the promoter of PpPDS to repress its transcription and simultaneously activates the expression of PpNCED1 by binding to its promoter. These findings elucidate the molecular mechanism by which PpZAT10 mediates ABA-induced carotenoid accumulation in yellow peaches, providing a novel strategy for enhancing carotenoid content and, consequently, fruit quality.

Peripheral nerve injury (PNI) can result in the loss of motor function and inflammatory pain, particularly in patients with diabetes. In this study, we developed an intelligent hydrogel (GBPVA) that responds to inflammatory stimuli, composed of boric acid-modified gelatin (GelBA) and polyvinyl alcohol (PVA), and loaded with chrysanthemum-derived exosomes (Exos). This hydrogel exhibits inflammation responsiveness. It can rapidly release exosomes within the inflammatory microenvironment, modulate macrophage polarization, and promote the transition of macrophages to the regenerative M2 phenotype, thereby ameliorating the inflammatory response, facilitating neural repair, and alleviating neuropathic pain. In vitro experiments demonstrated that GBPVA/Exos possesses excellent mechanical properties, self-healing capability, strong tissue adhesion (with an adhesion strength to porcine skin of up to 41.92 kPa), and biocompatibility, supporting the adhesion, migration, and axonal growth of both neuronal and Schwann cells. In vivo animal models revealed that this hydrogel significantly inhibits inflammatory responses, promotes the regeneration of nerve fibers and myelin sheaths, improves motor function (with the sciatic functional index (SFI) recovering to -23.8 after 4 weeks of GBPVA/Exos treatment), reduces muscle atrophy, and effectively alleviates diabetes-associated neuropathic pain (After GBPVA/Exos treatment, the paw withdrawal threshold (PWT) in rats increased to approximately 53.1 g, approaching the baseline level (∼55.0 g) observed prior to PNI. Moreover, the thermal withdrawal latency (TWL) increased from 13.4 s to 14.7 s following GBPVA/Exos treatment.). This multifunctional hydrogel integrates natural plant-derived exosomes with intelligent materials, offering a novel strategy for the treatment of diabetic peripheral nerve injury.

Xanthine oxidase (XOD) inhibitors are central to hyperuricemia and gout management, but efficient, reusable enzyme-based screening platforms remain limited. In this study, XOD immobilized Fe₃O₄@SiO₂- nanoparticles (Fe₃O₄@SiO₂-XOD NPs) were developed and optimized as a reusable screening platform and applied to identify bioactive XOD inhibitors from Trichosanthes anguina (Snake Gourd). Fe₃O₄@SiO₂-XOD NPs were synthesized via glutaraldehyde-mediated crosslinking and characterized by FTIR, XRD, and SEM. Optimal immobilization was achieved at 15% glutaraldehyde, pH 7.5, 25 °C, and 1 h incubation. The immobilized enzyme retained over 65% of its activity after eight reuse cycles and exhibited high specificity toward active ligands as validated using allopurinol. Using this platform, the ethanol extract of Trichosanthes anguina inhibited XOD with an IC₅₀ of 383.50 ± 11.98 μg/mL, while the ligand-fished fraction showed significantly enhanced inhibition (IC₅₀ = 77.17 ± 6.80 μg/mL). UPLC-Q-TOF-MS/MS analysis identified eleven flavonoids, among six as potential XOD inhibitors, which was supported by molecular docking showing strong binding affinities (-6.6 to -8.3 kcal/mol), involving multiple hydrogen bonds and hydrophobic interactions with key XOD active-site residues. Furthermore, in an HK-2 cell-based HUA model induced by XOD and adenosine, the ligand-fished fraction significantly and dose-dependently reduced UA production at non-cytotoxic concentrations, with effects comparable to allopurinol. Overall, the Fe₃O₄@SiO₂-XOD NPs platform provides an efficient and reusable strategy for screening natural XOD inhibitors. Trichosanthes anguina was confirmed as a rich source of anti-hyperuricemic flavonoids, supporting its further exploration for gout management.

As one of the typical extracellular contractile injection systems (eCISs), Photorhabdus virulence cassette (PVC) can be released from bacterial cells to inject into eukaryotic cells, while the signal peptides (SPs) direct the loading of heterologous proteins into PVC, making PVC an ideal model for in vitro protein delivery. In this study, the N-terminal sequences (NTSs) of 64 genes were tested for the loading effect, among which 45 NTSs were verified as SPs. Sequence analysis revealed that hydrophilic NTSs were more likely to guide cargo loading, possibly due to their interaction with PVC15 ATPase. Additionally, through SPs identification, an unclassified effector named Photorhabdus asymbiotica anti-phagocytic protein (PAAP) was identified. When delivered by PVC into J774A.1 murine macrophage cells, significant cell rounding was observed. Moreover, the phagocytic activity of macrophages against bacteria was markedly reduced following PVC-PAAP treatment. Transcriptomic and western blotting analyses revealed that the upregulation of Klf2, RhoB, Tsc22d3, and Ezr genes, and the reduction in P21-activated kinase (PAK) expression, potentially lead to cytoskeletal changes and decreased phagocytosis. In summary, this study broadened the scope of SPs of PVC, elucidated the differences in physicochemical properties between SPs and nSPs, and identified a new PVC effector protein along with its biological function in cell morphology and phagocytosis.