International Journal of Biological Macromolecules最新文献

Exogenous non-starch substances can modify the functional properties of starch by forming complexes with starch. The tuberous roots of Tetrastigma hemsleyanum contain abundant polysaccharides, yet the potential of these polysaccharides in starch modification remains unexplored. This study investigated the effects of polysaccharides extracted from the tuberous roots of T. hemsleyanum (PST) on the physicochemical properties, digestibility, and structure of potato starch (PS). PST addition significantly reduced the PS gelatinization degree and promoted its retrogradation. PST inhibited the swelling power of PS during gelatinization, diminished the amylose leaching, and reduced the pasting viscosity. When the addition concentration of PST was 10%, the peak viscosity declined from 3930 cP to 1305 cP, while enhancing the setback viscosity from 192 cP to 312 cP. Meanwhile, PST enhanced the viscoelasticity of the PS gel. Additionally, PST delayed the digestion rate of PS, with the ultimate digestibility declining from 62.4% to 53.3% upon incorporation of 10% PST. PS/PST complexes exhibited a reinforced network structure and increased crystallinity. These findings suggested that PST can be used to regulate the glucose release of starchy foods, providing new insights for the development of starch-based functional foods.

Type 3 Resistant starch (RS3) has garnered increasing attention for its potential therapeutic effects in inflammatory bowel diseases (IBD), such as colitis. However, the impact of different crystalline forms of RS3 on the alleviation of colitis remains unclear. This study examined A-type and B-type crystalline RS3 microparticles (ARS and BRS) derived from debranched waxy maize starch. BRS exhibited higher crystallinity and RS content than ARS by around 8% and 11%, respectively. Treatment with ARS and BRS led to a 12.5-31.1% reduction in cytokine levels (TNF-α, IL-1β, IL-6) compared to NS, while improving colon morphology. Notably, BRS more effectively promoted Lactobacillus growth, suppressed harmful Patescibacteria, and increased SCFA levels (by 5.1 μmol/g) compared to ARS. The findings underscore the significance of RS3's crystalline structure in its anti-inflammatory potential, suggesting it as a promising strategy for colitis management and offering insights into RS's benefits for gut health.

Transmission of AMR through edible fishes has recently upsurged as a global health hazard owing to its potential impact on human and one health. India, as the second largest consumer of edible fish faces a high risk of AMR transmission, given the nutritional value, accessibility and affordability of fishes to people from all economic classes. The present study investigated the presence of ARGs in edible muscle, gills and intestines of five commercially important fishes, Nemipterus japonicus, Sardinella longiceps, Selaroides leptolepis, Stolephorus indicus, and Sardinella gibbosa sourced from two major densely populated cities of the East coast (Chennai) and the West coast (Mangalore) using adaptive nanopore sequencing technique. A total of 54 distinct ARGs associated with 12 classes of AMR were detected across both coasts with enhanced resistance observed towards aminoglycosides, macrolides, beta lactam, tetracycline and chloramphenicol. Cumulatively, the most abundant ARGs across both coasts includes cxpE, aac(3')-IIa, aac(6)-IB-cr, oqxA and oqxB. However, significant variation in the distribution of ARGs among the two coasts were studied with varying abundance patterns. Furthermore, this study predicted human pathogens such as Klebsiella sp., Escherichia sp., Staphylococcus sp. and Pseudomonas sp. as putative reservoirs of ARGs indicating potential zoonotic and foodborne transmission to humans. This study offers a novel, and in-depth characterization of edible fish associated AMR contamination in east and West coast of India, providing essential data for assessing the public health hazards posed by ARGs and the pathogenic taxa.

Diacylglycerol acyltransferase (DGAT) is a membrane-embedded, acyl-CoA-dependent enzyme that catalyzes the terminal and rate-limiting step of neutral lipid biosynthesis. However, the structural determinants governing its catalytic function remain poorly defined, hindering rational engineering of this enzyme family. Here, we characterized Saccharomyces cerevisiae DGAT (ScDGA1) through integrative structural prediction, molecular dynamics (MD) simulations, and substrate-docking analyses, and provide the first mechanistic evidence that dynamic tunnel opening governs acyl-CoA access to the catalytic center. Alanine scanning identified Q282 as a key constriction point within the acyl-chain tunnel, and saturation mutagenesis yielded the Q282F variant, which substantially enhanced triacylglycerol accumulation in vivo (1.85-fold, 148 mg/g DCW). Biochemical assays revealed increased lipid droplet biogenesis and a substrate preference shift toward oleic acid. MD analyses further showed that Q282F reduces internal water occupancy, enlarges tunnel geometry, and stabilizes open conformations, thereby lowering the energetic barrier for substrate diffusion. These findings elucidate the molecular basis of DGAT catalysis and establish a structure-guided framework for engineering acyltransferases toward customized lipid biosynthesis.

RNA-binding proteins (RBPs) govern mRNA fate and critically regulate spermatogenesis. The poly(rC)-binding protein 2 (PCBP2), a testis-enriched RBP, remains uncharacterized in spermatogenesis. In this study, we identified and validated PCBP2 downregulation in testicular tissues from patients with non-obstructive azoospermia (NOA) by integrating bulk and single-cell RNA sequencing (scRNA-seq) datasets. To investigate its function, we generated mice with a germline-specific ablation of Pcbp2. These mice exhibited delayed meiotic prophase and impaired spermiogenesis. Specifically, we observed a reduction in mid-pachytene spermatocytes and a distinct developmental arrest at step 9 of spermiogenesis. Mechanistically, integrated IP-MS, RNA-Seq, and RIP-Seq analyses revealed that PCBP2 recruits hnRNPU and DDX5 to key transcripts related to meiosis (Spo11, Tdrd5 and Brme1) and spermiogenesis (Eif4g3, Piwil1 and Dlec1), thereby orchestrating mRNA stability and alternative splicing of target genes. This study establishes PCBP2 as an indispensable multifunctional RBP required for meiotic progression and spermiogenesis. Our findings identify a novel mechanism of RBP-driven male infertility and indicate PCBP2 as a potential diagnostic marker and therapeutic target for NOA.

The genus Polygonatum is distributed throughout the temperate northern hemisphere and has been widely used worldwide as a food and medicinal ingredient. Polysaccharides are an important active component in Polygonatum. More and more studies have shown that Polygonatum has a wide range of biological functions. In this paper, we reviewed the latest progress of extraction, separation, structure, biological activity, and structure-activity relationship of Polygonum polysaccharides, especially the influence of various processing methods on the structure-activity of Polygonatum polysaccharides, such as nine steaming and nine drying, wine-processed, honey-processed, and other processing methods. Different processing methods would lead to differences in structure and the various biological activities of polysaccharides. In addition, we also discussed the product development and application prospects of Polygonatum polysaccharides in pharmaceutical, food, cosmetics, and materials fields, discussed the challenges and prospects of fruit polysaccharides research, and laid a theoretical foundation for the further development and application of Polygonatum polysaccharides in nutrition and medicine fields.

Sustainable, multifunctional packaging with real-time freshness monitoring and shelf-life extension is crucial for beef quality and safety. This research investigates the incorporation of an ammonia-sensitive cobalt-based metal-organic framework (Co-MOF) into a chitosan (CS) polymer matrix to develop a functional composite film designed for extending the shelf life of yak meat. Results showed uniform Co-MOF evenly distributed in CS matrix, bonded steadily with CS via hydrogen bonds and covalent (Co-COOH).The integration of Co-MOF marked improvement in its structural strength, achieving a tensile strength of 15.3 MPa and a breaking elongation of 46.64% at 6 wt% Co-MOF. The films demonstrated outstanding barrier performance, showing water vapor transmission rate (WVTR) of 0.934 × 10^-3 g·cm/cm²·KPa·h and an oxygen permeability of 6.275 cm³/m²·24h·0.1 MPa. The water contact angle was 85°, and the film showed superior ultraviolet shielding with 16.74% transmittance at 400 nm when the Co-MOF content was 8 wt%. In terms of preservation, the CS/MOF films demonstrated excellent antibacterial activity. The films monitored yak meat freshness via color change, extending its shelf life by 2 days. Additionally, the films exhibited good biodegradability, fully degrading within 78 days when buried in soil, releasing approximately 97 μg of cobalt from the CS/MOF-8 film.

Silk fibroin (SF), a key component of the hierarchical structure of silkworm cocoons, can be mechanically processed into fibroin nanofibrils (FNF). This underexplored route enables fast, sustainable and scalable approach for FNF production without relying on organic solvents or costly chemicals. In this study, we combined FNF obtained by mechanical disintegration with gold nanoparticles (AuNPs) to obtain FNF@AuNP nanohybrids, which were integrated into wearable microneedle patches for colorimetric monitoring levodopa, an essential drug for managing Parkinson's disease (PD). The approach demonstrates the potential of biobased films embedded in 3D-printed devices to serve as point-of-care wearable sensors, offering user-operated, real-time assessment of chronic conditions. Specifically, when integrated with 3D-printed microneedle (MN) platforms, the FNF@AuNP casting films acted as a colorimetric indicator of high levels of levodopa in interstitial fluid (ISF). The color changes were more evident when auxiliary paper discs were used in the analysis, combined with the FNF@AuNP films. The colorimetric study was associated with image processing, and the data analysis was performed using Interactive Document Map (IDMAP) for information visualization. In simulated interstitial fluid, the colorimetric method successfully indicated the presence of levodopa in ISF, when its concentrations were above 50 μM, with the required selectivity. Given that both sub-therapeutic and excessive levodopa doses can exacerbate motor symptoms, the proposed FNF@AuNP-based wearable sensor represents a promising strategy for supporting dose management in PD therapy, enabling first-line, personalized feedback for patients.

In this study, we developed triptolide (TP)-loaded open-pore PBVHx microspheres (TP@OPMs) and compared their anticancer and embolization capabilities with those of TP-loaded sealed PBVHx microspheres (TP@SMs). TP@OPMs, characterized by an open surface and interconnected internal pores, showed higher water absorption (2860%) and porosity (79.69%), but slightly lower TP encapsulation efficiency (79 ± 0.32%) compared to TP@SMs, and achieved sustained TP release of 75.29% over 21 days. All PBVHx microspheres without TP demonstrated good biocompatibility, but TP@OPMs exhibited superior inhibitory effects on HepG2 cells compared to TP@SMs, with a hemolysis rate below 5%. In in vivo central arterial embolization experiments, TP@OPMs outperformed other microspheres and commercial gelatin microspheres, achieving the highest necrosis rate (50.70%). This resulted in the successful induction of ischemic necrosis and tissue detachment. These findings suggest that TP@OPMs are not only an effective drug delivery system but also have significant potential in embolization applications. This strategy provides a promising approach for the treatment of hepatocellular carcinoma and other malignant tumors.