International Journal of Biological Macromolecules最新文献

Iron (Fe) toxicity is a major abiotic stress that compromises crop productivity and quality, yet the underlying molecular mechanisms in medicinal plants like ginseng (Panax ginseng C.A. Meyer) remain poorly elucidated. Here, the core transcription factor PgbHLH149 was identified as being up-regulated by exogenous silicon (Si) and acted as a key regulatory factor in response to Fe toxicity in ginseng. Overexpression of PgbHLH149 in both Arabidopsis and ginseng significantly enhanced Fe stress tolerance through a dual mechanism: 1) modulating elemental homeostasis by reducing Fe accumulation and promoting the uptake of beneficial elements (Ca, Mg, Si); and 2) activating the antioxidant system, thereby increasing enzyme activities (SOD, POD, CAT, APX) and diminishing reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Furthermore, yeast two-hybrid screening revealed that PgbHLH149 interacts with a serine/threonine protein kinase (STPK1) and a fellow transcription factor (bHLH74). And bimolecular fluorescence complementation and co-immunoprecipitation assays confirmed the in vivo interaction between PgbHLH149 and STPK1 in the nucleus. LC-MS/MS analysis further identified phosphorylation of PgbHLH149 at serine-133 by STPK1, indicating post-translational regulation. Under silicon conditions, PgbHLH149 forms a regulatory "STPK1-PgbHLH149-bHLH74" module, which may achieve Fe detoxification by synchronizing elemental homeostasis and antioxidant defense system. Our findings unveiled a novel transcriptional regulatory network for Fe stress tolerance in ginseng, providing crucial molecular targets for breeding rust-resistant varieties and advancing soil remediation strategies in Fe-contaminated soils.

α-L-Rhamnosidase is a significant biocatalyst that specifically cleaves terminal α-L-rhamnose group from natural flavonoid diglycosides, enabling the biocatalytic production of high-value flavonoid glucosides like prunin from naringin. Compared to its precursor naringin, prunin exhibits superior solubility and bioavailability, making this enzymatic conversion commercially valuable for the food and pharmaceutical industry. However, the industrial application of free α-L-rhamnosidases faces significant challenges, including enzyme instability, difficulty in recovery, and unsatisfactory reusability. To address these issues, this study developed an innovative magnetically recoverable biocatalyst (Fe₃O₄-Rha) through covalent immobilization of recombinant α-L-rhamnosidase from human fecal metagenome onto Fe₃O₄ nanoparticles using EDC/NHS chemistry, and the immobilization parameters were systematically optimized. The successful preparation of Fe₃O₄-Rha was verified by TEM, FTIR, TGA, and SQUID analysis. Fe₃O₄-Rha retained the catalytic property of free Rha in terms of optimal pH and temperature but exhibited superior tolerance on organic solvent especially ethanol and isopropanol. Moreover, Fe₃O₄-Rha could effectively biotransform naringin to prunin and maintained 61.34% of initial activity after 5 cycles. In a scaled-up reaction system, Fe₃O₄-Rha also efficiently converted naringin into prunin and the complete conversion was achieved within 10 h. This work successfully developed a magnetically recoverable immobilized α-L-rhamnosidase system for the efficient and reusable biotransformation of naringin, offering a promising approach for the enzymatic modification of bioactive small molecules using biological macromolecular catalysts.

The widespread use of non-degradable plastic food packaging poses serious environmental and food safety concerns, motivating the development of biodegradable intelligent packaging systems capable of real-time freshness monitoring. In this study, a bilayer antibacterial indicator film was fabricated, consisting of an inner gellan gum/Artemisia sphaerocephala Krasch gum (GG/ASKG) layer and an outer cellulose acetate (CA) layer, incorporating optimized nano‑zinc oxide (2%) and nano‑silicon dioxide (1.5%). Films were prepared via solution casting and characterized by UV-blocking, water vapor permeability (WVP), water contact angle, antibacterial activity, and colorimetric response during fish storage. Nano-SiO₂ significantly enhanced barrier properties, increasing UV-blocking efficiency to >90%, raising water contact angle above 90°, and reducing WVP by 46.3%, whereas nano-ZnO mainly improved antimicrobial performance, producing inhibition zones of 14.04 mm (E. coli) and 11.18 mm (S. aureus), ~30% larger than the control. The absence of new chemical bonds confirmed that nanoparticles interacted physically with the polymer matrix. All films exhibited distinct color changes in stored fish, transitioning from rosy pink (fresh) to yellowish pink (slightly spoiled), and ultimately to a greyish-purple hue (spoiled), enabling visual freshness monitoring and extending fish shelf life by ~1 day at room temperature. Furthermore, L, a, b color parameters were incorporated into a backpropagation artificial neural network (BP-ANN) with Batch Normalization and Dropout, achieving high predictive performance for TVB-N values (R² = 0.954, classification accuracy = 100%), demonstrating that visual color changes could be quantitatively translated into reliable freshness indicators. This work highlights a novel strategy that integrates multifunctional nanomaterials and data-driven algorithms for intelligent, biodegradable food packaging.

Invasion of bacteria or pathogens into the bone causes bone infection leading to inflammation and damage to bone tissue. The current treatment modalities for chronic osteomyelitis is antibiotic treatment using bone cement beads. Continuous release of antibiotics from bone cements for a longer duration resulting in bacterial resistance. To overcome these limitations, antibiotics incorporated hydrogel-coated composite bone cement beads provide effective antibacterial activity, possess an ECM-like environment for healing and localized drug delivery. Therefore, we developed a ciprofloxacin incorporated alginate hydrogel (C-AL) coated tetracalcium Phosphate-Nano diopside (BCD) composite bone cement beads (C-AL-BCD) to treat bone infections and promote regeneration. The incorporation of Nano-diopside into the bone cement beads promotes both osteogenesis and angiogenesis. The prepared beads were characterized using SEM, FTIR, XRD, and EDAX analysis. The in vitro biocompatibility, osteogenic activity of the prepared BCD beads was studied using biomineralization, RUNX2, and OPN expression in dental follicle stem cells, demonstrating an enhanced osteogenic mineralization and markers expression. Similarly, in vitro angiogenic studies of the BCD beads were studied using Tube formation, and Migration assay in endothelial cells and showed an enhanced angiogenic activity. Furthermore, biocompatibility, antibacterial, and anti-biofilm activities of the C-AL-BCD beads were studied and exhibited good biocompatibility, antibacterial and anti-biofilm activity. In vivo antibacterial activity was analysed in the Drosophila melanogaster fly model, with C-AL-BCD beads showing a higher survival rate than infected groups. Thus, this developed C-AL-BCD beads could be an ideal system for the synergistic treatment of bone infections and vascularized bone regeneration.

The integration of natural lignocellulose with biodegradable polymers offers a sustainable approach to developing biomimetic tissue scaffold. Here, we developed a jute microfiber/polycaprolactone nanofiber (JMF/PCLNM) composite as a biomimetic scaffold to replicate the matrix environment for cellular functionality. Morphological evidence confirmed smooth, uniform, and bead-free nanofibers morphology with up to 15 wt% JMF, whereas higher JMF loadings led to bead formation, which became increasingly pronounced at 30 wt%. FTIR analysis confirmed the coexistence of both component polymers without disruption of the β-glycosidic linkages in jute cellulose. JMF addition slightly shifted and broadened PCL XRD bands, with a new 28.32° band indicating cellulose de- and recrystallization. JMF loading enhanced scaffolds' hydrophilicity, lowering the water contact angle from ~131° (PCLNM) to ~121° (JMF/PCLNM) (15 wt% JMF). JMF/PCLNM showed a marked increase in the swelling capacity, from 0.15 g/g for pristine PCLNM to 2.01 g/g for 15 wt% JMF content. A mechanism of the developed scaffolds' in vitro biodegradation was proposed, showing that JMF/PCLNM underwent hydrophilicity-driven water diffusion and ester bond hydrolysis, accompanied by dislocation of crystalline domains. In vitro assays using COS-7 fibroblast cells demonstrated low cytotoxicity, intact membrane integrity, and sustained proliferation over one week of culture. Overall, the JMF/PCLNM composite exhibits favorable structural and biological attributes, highlighting its potential as a sustainable biomimetic scaffold for soft tissue engineering applications.

The presence of lignin-rich oxygen-containing groups significantly increases the potential of supercapacitors. However, the heterogeneity of lignin limits their use in industry. In this study, eucalyptus wood was used as the raw material to obtain highly reactive fractionated lignin through solvent extraction and fractionation processes. After fractionation, the weight-average molecular weight decreased from 27,760 to 19,665, and the polydispersity decreased from 2.70 to 2.11. The fractionated lignin was subsequently used to partially replace phenol, synthesizing a series of lignin-based phenolic resin-derived carbon materials, which were then applied in supercapacitors. Electrochemical tests indicated that the material with a 40% substitution ratio exhibited the optimal performance. Accordingly, all subsequent investigations were focused on this optimal ratio. After carbonization, ALPFC (the 40% acetone-fractionated lignin-based phenolic resin carbon material) had a high specific surface area of 3210 m²·g^-1, outperforming carbon materials derived from phenolic resin (2142 m²·g^-1). Electrochemical tests reveal that ALPFC has a specific capacitance of 335.5 F/g at a current density of 0.5 A/g, which is significantly greater than that of phenol-formaldehyde resin (196.2 F/g). Moreover, ALPFC has excellent double-layer capacitance characteristics and outstanding cycling stability, with a capacitance retention rate of 110.88% after 10,000 cycles at 10 A/g. In a dual-electrode system, there is a minimal decrease in the specific capacitance, with a capacitance retention rate of 98.15%. These findings offer an effective pathway for the green and low-carbon preparation of supercapacitor electrode materials, while also verifying and establishing a feasible approach to efficiently utilize lignin without compromising the key properties of the resin.

This study presents a novel stable isotope labeling strategy based on deuterium exchange for monitoring the degradation of κ-carrageenan tissue engineering scaffolds. This approach addresses the challenge of tracking scaffold fate under physiological conditions. Through optimized hydrogen‑deuterium exchange using 10% palladium‑carbon catalyst over 72 h, we achieved a deuterium incorporation efficiency of 65.01% as verified by nuclear magnetic resonance and mass spectrometry analysis. Deuterated and non-deuterated κ-carrageenan were blended at a 1:1 mass ratio to form composite scaffolds, enabling real-time degradation monitoring via fourier transform infrared spectroscopy through tracking of deuterium-related spectral shifts. Both scaffold types exhibited highly consistent degradation behavior, which was described by the Box-Lucas kinetic model, showing correlation coefficients of 0.984 and 0.982 and yielding degradation rate constants of 1.71 day^-1 and 1.83 day^-1 for the labeled and unlabeled scaffolds, respectively. The close agreement validates deuterium labeling as a reliable and sensitive monitoring method. This study establishes a methodological framework for monitoring the in vivo degradation of tissue engineering scaffolds, demonstrating significant potential for clinical translation.

This study evaluated the synergistic efficacy of silver nanoparticles (AgNPs) and cinnamon oil, with criteria based on reducing minimum effective concentrations while maintaining or enhancing antifungal activity compared to individual treatments. The antifungal effects of AgNPs and the cinnamon oil/β-cyclodextrin complex, as well as their impact on chitosan film properties, were investigated for avocado preservation. Preservation performance was assessed through respiratory rate, pH, firmness, weight loss, skin color, total soluble solids, cell wall-degrading enzyme activity, and disease incidence in avocados infected with Aspergillus niger. AgNPs and cinnamon oil showed antifungal activity against A. niger at 62.5 ppm and 5 μL/mL, respectively. Their combination (AgNPs at 31.25 ppm with cinnamon oil at 2.5 μL/mL) exhibited a synergistic effect, reducing antifungal agent usage while maintaining efficacy. Incorporation into chitosan films altered transparency, color, and surface texture, making them rougher and uneven, while thickness remained unchanged (p > 0.05). The combined formulation (CAg_31.25CB_2.5), consisting of chitosan (1% w/v) with AgNPs (31.25 ppm) and cinnamon oil (2.5 μL/mL), significantly extended avocado shelf life, and disease incidence was completely inhibited even under artificial inoculation conditions after 8 days, compared to complete deterioration in controls. Overall, AgNPs, cinnamon oil, and chitosan acted synergistically as antifungal agents and formed a biological barrier that improved coating adhesion, delayed weight loss, pH changes, total soluble solids, and color shifts, enhanced firmness, lowered respiration rates, reduced cellulase activity, and protected avocados from pathogens during storage.

Chitin and its derivative chitosan were isolated from the pupal exoskeletal discards of Eri (Samia ricini) silkworm, and their properties were compared to shrimp-based commercial chitosan for potential alternative sourcing and to assess its application as a fruit coating material. Through acid-base treatment, Eri chitin was extracted and variously deacetylated chitosan was then produced by differential alkaline treatment time. The FTIR and solid-state NMR analyses confirmed their α-nature. Concentrated alkali treatment on Eri and shrimp chitin for the same duration yielded Eri chitosan with lower molecular weight but higher deacetylation% than the shrimp-based chitosan. TGA revealed a good thermal stability and lower mineral content pointing to the purity of Eri chitosan extraction. XRD patterns indicated treatment time-proportionate deacetylation and amorphosity, corroborated by SEM texture analysis. The Eri chitosan showed biodegradability, cyto-compatibility, excellent anti-oxidative and anti-microbial capacities and had an analogous efficiency in preserving the quality and extending the post-harvest shelf life of Java plums when equated to shrimp-derived chitosan. Overall, the study suggests that chitosan obtained from Eri pupal discard can serve as a viable alternative coating material for fruit preservation and other industrial applications, hence addressing the circular economy goals.