International Journal of Biological Macromolecules最新文献

Non-heme diiron oxygenases (NDOs) are a widely distributed family of metalloenzymes that use a dinuclear iron center to activate molecular O₂ and perform a broad range of oxidative reactions. These enzymes play central roles in carbon-nitrogen cycling and in the biosynthesis of many natural products. Unlike systems that rely on a single conserved active-site architecture, NDOs feature diverse metal coordination environments. These include the classic histidine/carboxylate-coordinated diiron center, systems in which the diiron cofactor assembles only upon substrate binding, and other noncanonical arrangements. In all cases, O₂ binds at the diiron core and is converted into reactive oxygen species that drive regio-, chemo-, and stereoselective oxidation of CH, NH, and CC bonds under physiologically mild conditions. Owing to favorable biocompatibility, broad substrate scope and mechanistic versatility, NDOs represent attractive catalysts for applications in synthetic biology and sustainable biomanufacturing. In the present review, current knowledge on family classification and representative catalytic functions were synthesized, active-site architectures were analyzed, catalytic cycles and substrate-binding strategies were described, and recent advances from structural biology, spectroscopy, computational modeling, and kinetic analysis were integrated. Through the evaluation of translational prospects in engineered biosynthetic pathways and green transformation platforms, the aim was to provide a rigorous conceptual framework to guide future mechanistic studies and protein-engineering efforts.

Developing sustainable engineering materials requires systems that merge renewable origin, mechanical resilience, thermal stability, and industrial scalability. In this study, bio-based polyamide 11 (PA11) was reinforced with yucca fibers extracted via two eco-designed routes, traditional (YT) and water retting (YWR), to create next-generation bio-composites processed through injection molding. The incorporation of yucca fibers significantly enhanced the mechanical properties of PA11. Traditionally extracted fiber-reinforced composite (PA11-YT5) enhanced tensile (35.02 MPa) and flexural strengths (43.08 MPa) compared to 34.83 MPa and 41.81 MPa for neat PA11. Meanwhile, the water-retted composites (PA11-YWR5) exhibited accepted strength (34.75 MPa in tensile, and 41.84 MPa in flexural) with greater impact resistance and improved thermal stability. Enhancing the Heat Deflection Temperature (HDT) is key for enabling bio-composites to operate in thermally demanding applications. Here, yucca reinforcement markedly improved thermal resistance: the neat matrix showed an HDT of 72.25 °C, while fiber incorporation increased it by +52% (PA11-YT5%) and + 55% (PA11-YWR5%). After hygrothermal aging (37 °C, 85% RH, 30 days), both systems retained over 98% of their initial strength in tensile, demonstrating high environmental durability. Life cycle assessment (i.e., LCA) confirmed a lower carbon footprint (≈1.27 kg CO₂ eq./kg) and reduced processing energy relative to neat PA11. The results of this study highlight yucca fibers as a compelling renewable alternative to widely used natural fibers, providing consistent mechanical reinforcement and notable thermal stability. Combined with their environmental advantages, these characteristics position yucca fibers as attractive candidates for sustainable automotive components and lightweight structural applications.

Circular RNAs (circRNAs) have emerged as critical regulators of colorectal cancer (CRC) progression; however, the biological function of circEIF2S2 remains largely unexplored. In this study, we investigated the expression, functional roles, and regulatory mechanisms of circEIF2S2 in CRC. Bioinformatic analyses and quantitative RT-PCR revealed that circEIF2S2 is significantly upregulated in CRC tissues and cell lines and is associated with unfavorable clinical outcomes. Functional assays demonstrated that circEIF2S2 silencing markedly suppressed CRC cell proliferation, migration, invasion, and immune checkpoint expression, while enhancing CD8⁺ T cell-mediated immune responses in co-culture systems. Mechanistically, circEIF2S2 predominantly localized in the cytoplasm and functioned as a competing endogenous RNA by sponging miR-646, thereby relieving miR-646-mediated repression of UHMK1. In addition, the RNA-binding protein EIF4A3 promoted circEIF2S2 biogenesis through direct interaction with EIF2S2 pre-mRNA. Rescue experiments confirmed that the oncogenic and immunosuppressive effects of circEIF2S2 were partially reversed by miR-646 inhibition or UHMK1 suppression. In vivo, circEIF2S2 depletion significantly inhibited tumor growth and liver metastasis in xenograft models. Collectively, these findings identify the EIF4A3-circEIF2S2-miR-646-UHMK1 axis as an important regulatory pathway involved in CRC progression and tumor-associated immunosuppression.

Decellularized extracellular matrix (dECM) has been widely used in tissue engineering and regenerative medicine due to its excellent biocompatibility and biological activities. In this work, the dECM was obtained by treating porcine Achilles tendon tissue via a combination of chemical, physical, and biological approaches. The obtained dECM was interpenetrated with genipin crosslinked quaternary ammonium chitosan (QCS) network to fabricate the composite genipin/QCS/dECM (QGD) hydrogels. The prepared QGD hydrogels exhibited an interconnected microstructure and a suitable water-absorption capacity. Furthermore, the QGD hydrogels exhibited strong adhesion to the surfaces of different matrices and various organs, including lung, liver, trachea, heart, and spleen. The remodelling of dECM gave the QGD hydrogels adjustable self-healing ability and mechanical properties. In addition, the QGD bio-adhesives exhibit effective antibacterial activity against the typical Gram-positive S. aureus and Gram-negative E. coli. 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging tests confirmed the antioxidant abilities of QGD hydrogels, and the cellular reactive oxygen species (ROS) scavenging potential was also investigated using RAW264.7 cells. Furthermore, the QGD hydrogels possessed excellent hemocompatibility, cytocompatibility, and cell pro-migration abilities. The results confirmed that the proposed QGD hydrogels could serve as potential bioadhesives for biomedical applications.

This study developed a low-fat pork gel based on Pickering emulsion stabilized by carboxymethyl chitin nanofibers (CMCNF) and carboxymethyl chitosan (CMCS), cross-linked with oxidized sodium alginate (OSA). Fourier Transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed the Schiff base cross-linking between OSA and the amino groups in pork protein, CMCS and CMCNF. With the increase in OSA content (0.5%-1.5%) at the same substitution ratio (30%), the water-holding capacity increased to more than 90%, the cooking loss decreased to less than 8%. At the highest substitution level (50%), the cooking loss was further reduced to 4.32%, and the hardness and gel strength were increased by about 4.7 times compared to control group. The water immobilization and gel network of the pork gels were enhanced. Rheological tests indicated strengthened viscoelastic properties, and in vitro digestion studies revealed delayed lipid digestion. These results indicate that the synergistic combination of the physical stability of Pickering emulsion and chemical cross-linking through a dynamic covalent network provides a strategy for developing structured fat substitutes, and promoting the development of healthy low-fat meat products.

In this study, lignocellulose and cellulose microfibers (LCMFs and CMFs) and nanofibers (LCNFs and CNFs) were produced from three types of date palm wastes: leaflet (L), rachis (R), and empty fruit bunch (E). Subsequently, micropapers (MPs) and nanopapers (NPs) were prepared from the micro/nanofibers. Different date palm wastes (E, R, and L) had significant differences in anatomy, morphology, and chemical composition of fibers compared to each other and other sources of cellulose. Bleaching increased the crystallinity index, while mechanical downsizing reduced it. The highest (9.03 g/cm³) and lowest (5.27 g/cm³) densities were observed in LCNF-E-NP and CMF-L-MP, respectively. CNF-L-NP had the highest burst strength (12.86 kPa·m²/g), and LCNF-R-NP the lowest (4.12 kPa·m²/g). In tear index, LCMF-L-MP showed the highest (7.43 mN·m²/g), and LCNF-L-NP the lowest (4.93 mN·m²/g). Regarding tensile strength, LCNF-E-NP exhibited the highest value (121.66 MPa), while LCMF-L-MP showed the lowest (33.39 MPa). This study demonstrated that date palm wastes, particularly empty fruit bunches, were promising renewable resources for the sustainable production of high-performance bio-based micro/nanofibers. The type of waste significantly affected the mechanical, physical, and functional properties of the resulting fibers and papers. Micro/nanopapers derived from empty fruit bunches exhibited the highest technical performance.