International Journal of Biological Macromolecules最新文献

The high glycemic index and rapid digestibility of refined rice flour pose challenges for blood glucose management, particularly for individuals with diabetes. This study investigated the efficacy of inulin-fortified rice flour in improving glycolipid metabolism in diabetic mice and elucidated the underlying mechanisms. Inulin with varying degrees of polymerization (DP) was screened using in vitro starch digestion and fecal fermentation, and the optimal formulation was then evaluated in db/db diabetic mice and normal mice. Supplementation with 10% short-chain inulin (SI; DP ≤ 10) significantly reduced the starch hydrolysis rate and estimated glycemic index (eGI) by 19.4% and 15.1%, respectively. In an 8-week animal study, diabetic mice fed the SI-fortified rice flour diet exhibited improved fasting blood glucose levels, enhanced glucose tolerance, and reduced dyslipidemia. Histopathology confirmed the alleviation of hepatic steatosis and pancreatic islet injury. Mechanistically, SI remodeled gut microbiota by enriching Muribaculaceae, Lactobacillus, and the butyrate-producing family Lachnospiraceae, while decreasing the Firmicutes-to-Bacteroidetes ratio. Consistently, SI markedly elevated cecal acetate and propionate concentrations by 45.9% and 55.2%, respectively. Collectively, short-chain inulin-fortified rice flour effectively alleviates glucose and lipid metabolic disorders, at least partially, by synergistically modulating gut microbiota composition and boosting short-chain fatty acid production. This presents a viable strategy for designing precision nutritional staple foods tailored to diabetic populations.

Heat stress (HS) adversely affects heat-sensitive ornamentals, including carnation (Dianthus caryophyllus L.), by impairing developmental stability and yield quality, which ultimately diminishes their commercial viability. The basic leucine zipper (bZIP) transcription factors are known mediators of stress adaptation, yet their functional roles in carnation thermotolerance remain largely unexplored. Here, we performed a genome-wide survey and identified 63 DcbZIP genes, which were systematically classified into 12 distinct subfamilies. Evolutionary analysis revealed lineage-specific expansion patterns, with the S subfamily emerging as the largest group (10 members). Gene structure analysis demonstrated conserved exon-intron organization within phylogenetic clades, with motif composition showing high consistency among subfamily members. Promoter analysis revealed abundant stress-responsive elements, suggesting potential roles in abiotic stress adaptation. Expression profiling demonstrated that DcbZIP48, a homolog of the H-group protein HY5, exhibited marked upregulation in a time-dependent manner under HS. Functional investigations revealed that overexpression of DcbZIP48 substantially enhanced thermotolerance in transiently transformed carnation, as reflected by improved growth performance, reinforced reactive oxygen species (ROS) scavenging capacity, elevated antioxidant enzyme activities, preserved chloroplast function, and altered the expression of heat-responsive genes. In contrast, silencing DcbZIP48 via virus-induced gene silencing (VIGS) exacerbated heat sensitivity. Collectively, these results uncover DcbZIP48 as a HY5-like transcription factor that positively regulates thermotolerance and provide foundational insights into the DcbZIP family in carnation, thereby supporting future genetic improvements for heat resilience in carnation.

The development of biodegradable packaging materials has gained increasing attention as alternatives to petroleum-based plastics. However, current bio-based packaging materials are based on a homogeneous structural design, which limits their effectiveness in inhibiting food spoilage caused by multiple factors, including microbial metabolism, oxidation reactions, and ultraviolet radiation. This study developed a Janus bilayer edible film utilizing gelatin and zein as substrates through layer-by-layer assembly technology, based on the Schiff base reaction and enzyme-catalyzed cross-linking. This approach achieved the co-loading of hydrophilic polylysine and hydrophobic curcumin, thereby endowing the bilayer film with antibacterial and antioxidant capabilities. Subsequently, the physicochemical properties, ultraviolet resistance, antibacterial activity, antioxidant activity, and fruit preservation ability of the Gelatin-Dialdehyde Starch-Polylysine/Zein-TGase-Curcumin (GDP/ZTC) films were investigated. The experimental results indicate that the GDP/ZTC film exhibits outstanding UV resistance, achieving a 100% UV blocking rate. It also demonstrates significant antioxidant activity, with DPPH and ABTS radical scavenging rate of 94% ± 0.09%, 87.08% ± 0.85%, respectively. The GDP/ZTC film inhibited S. aureus (65.35% ± 0.6%) and moderately inhibited E. coli (21.53% ± 1.22%), showing a Gram-positive-biased antibacterial effect. Moreover, the GDP/ZTC film performed excellently in blueberry preservation experiments, effectively maintaining the appearance, weight (with a weight loss rate of only 4.45% ± 0.51%), hardness (with a decrease of only 0.56 N), and anthocyanin content of blueberries even after 8 days. Overall, the Janus bilayer combines outstanding antioxidant/UV-barrier performance with selective Gram-positive-biased antibacterial function; moderate E. coli inhibition reflects a structure-function trade-off, highlighting sustainable food-packaging potential.

The biomedical potential of chitosan (CS) in wound healing is constrained by poor solubility and processability. Herein, we report a green and efficient route to synthesize water-soluble sulfated chitosan (SCS) with controlled sulfation patterns, using a sulfamic acid-urea deep eutectic solvent (DES). Comprehensive characterization (FTIR, ¹³C and HSQC NMR, HPSEC-MALLS-RI, and elemental analysis) verified tunable sulfation and molecular weights, with zeta potential further delineating the corresponding surface properties. Biological evaluations demonstrated that SCS possesses excellent biocompatibility, promotes cell migration, enhances TGF-β1/VEGF secretion, and facilitates angiogenesis, collagen deposition, and extracellular matrix remodeling. Structure-activity analysis revealed sulfation patterns determined bioactivity, with 6-O-sulfated SCS demonstrating superior wound closure rates (96.2% in 6-O-SCS vs. 88.6% in control group on 12 day post-treatment). This study provides a sustainable approach to SCS production and highlights its therapeutic potential in wound management.

High Mobility Group Box 1 (HMGB1) is a valuable therapeutic target in inflammatory, autoimmune diseases, and cancer. Recently, some of us identified a set of anti-HMGB1 aptamers, folding into G-quadruplex structures of different topology. Among them, L12 and L41 were the most effective aptamers as for affinity and activity towards the protein. Here, nuclear magnetic resonance (NMR) spectroscopy, corroborated by size exclusion high performance liquid chromatography (SE-HPLC) and circular dichroism (CD), allowed defining the structural features of L12 and L41. In-depth structural details were obtained for the monomeric forms of these aptamers in a K⁺-rich (100 mM K⁺) buffer, mimicking the intracellular environment. Under these conditions, both L12 and L41 folded in hybrid G-quadruplex structures. By cross-referencing the obtained data, we inferred that these structures were also the main monomeric folded species in the Na⁺-rich Phosphate Buffered Saline (PBS) buffer, mimicking the extracellular environment, suggesting that these aptamers share similar recognition patterns when interacting with the target protein. However, in PBS a higher amount of hybrid-2 G-quadruplex was observed for L12 than L41. Biolayer interferometry (BLI) analysis demonstrated a preference of HMGB1 for L12 over L41, in line with in vitro assays, showing higher ability to inhibit the HMGB1-induced cell migration for L12 than L41. These findings suggest that HMGB1 recognizes the hybrid-2 G-quadruplex folding of these aptamers, present in higher degree in L12 than L41. In summary, this work provides precious insights into the conformational preferences of L12 and L41, of crucial importance to design more effective HMGB1 inhibitors.

With the growing consumer demand for fresh and safe foods, intelligent packaging materials that monitor food quality in real time have attracted significant attention. Here, we report a pH-sensitive sodium alginate/polyvinyl alcohol/myricetin nanocrystals (SPMH) film as multifunctional intelligent food packaging. The prepared film showed satisfactory film-forming ability, biodegradability, and mechanical properties (83.62 MPa). Moreover, SPM-H film exhibited excellent water vapor barrier and oxygen barrier properties, reaching 7.4 × 10^-11 g·m·m^-2·Pa^-1·s^-1 and 242.51 cm³/m² d 0.1 MPa, respectively. Notably, the incorporation of water-soluble myricetin nanocrystals (MNC), obtained via anti-solvent crystallization, imparted superior and multifunctional properties that go beyond conventional natural pigments. The SPM-H film exhibited imparted remarkable antibacterial, antioxidant, and UV shielding properties, thereby extending food shelf life by one day compared to conventional polyethylene (PE) packaging. Most importantly, the MNC endowed the film with a distinct dual-mode (colorimetric/fluorescence) pH-responsive behavior, a feature rarely achieved by most natural pigments, which significantly enhances the reliability of spoilage monitoring. These findings emphasize the potential of SPM-H films as sustainable, multifunctional intelligent food packaging for food preservation and safety monitoring.

Chitosan (CH) is a well-known biocompatible, antibacterial biopolymer with distinct merits (e.g., infection control) for wound healing. However, like many other biopolymers, its bioactivity and mechanical stability are limited and need to be improved to promote the wound healing process. In this study, CH films were strengthened and biofunctionalized through incorporation of recombinant collagen type III (rCol) loaded mesoporous bioactive glass nanoparticles (mBGNPs). The addition of rCol not only supplies further biochemical cues for promotion of cell activities and raises bioactivity, but also firmly links CH and mBGNPs through physicochemical bonds, thereby assuring uniform distribution of the nanoparticles within the CH matrix. In this study, it was shown that inclusion of rCol-mBGNPs increases the mechanical properties of the CH composite film compared to the pristine CH films, as reflected in notably enhanced stiffness (516 MPa vs. 208 MPa) and tensile strength (52 MPa vs. 28.5 MPa). Additionally, rCol-mBGNPs could stimulate the L929 cell viability and cell migration through the co-release of pro-healing ions such as Ca²⁺ and rCol molecules and endowed the CH films with a bioactivity effect, reflected in the formation of a calcium phosphate surface biomineral layer. The rCol-mBGNP/CH composite film could successfully inactivate gram positive (S. aureus) and gram-negative (E. coli) bacteria. Furthermore, in vivo studies revealed the raised collagen deposition and accelerated wound closure rate of the CH composite films containing rCol-mBGNPs and their anti-inflammatory and pro-epithelialization effect. Taken together, rCol-mBGNP/CH composite films were shown to possess favourable mechanical and biological properties that make them an attractive choice for wound healing applications.

Heparan sulfate (HS) proteoglycans mediate the cellular uptake of tau, a critical step in the prion-like spread of tau pathology in Alzheimer's disease. In this study, we tested if several marine sulfated glycan of diverse structures can inhibit the tau-HS interaction. Through experiments of SPR we found that marine-derived sulfated fucans bind tau with similar affinity to heparin, whereas fucosylated chondroitin sulfates (FucCS) from several holothurian species bind tau with substantially higher affinity. Using solution NMR, we further characterized FucCS-tau interactions with residue-level resolution, revealing complex binding behavior distinct from heparin-tau binding. A high-affinity site is observed as peak intensity loss spanning the middle of PRR2 through R' of tau at low FucCS concentration, whereas another weaker binding site is characterized by both chemical shift perturbation and gradual peak intensity attenuation from the end of N2 through the middle of PRR2. Finally, we demonstrated that FucCSs inhibit tau uptake in SH-SY5Y cells with an IC₅₀ of 130 μg/mL, shown by both confocal microscopy and flow cytometry. Together, these findings have identified marine-derived polysaccharides as promising candidates for therapeutic development targeting tau-HS interactions.