AMB Express最新文献

Serpula lacrymans is the most destructive brown-rot fungus affecting timber in temperate regions, causing severe economic losses in construction and cultural heritage. Conventional chemical treatments are largely ineffective, as they act only on wood surfaces and fail to eradicate fungal growth within deeper layers. Previous studies have described the cellulolytic activity of S. lacrymans as weak and strictly substrate-inducible, despite genomic evidence for GH12-type endoglucanases. Moreover, cultivation in traditional malt- or CMC-based media often yields insufficient biomass, limiting reproducibility of biochemical assays and obscuring the true enzymatic spectrum. Here, we report that cultivation in Murashige-Skoog salt medium supplemented with sucrose markedly improves biomass yield and metabolite accumulation, enabling reliable physiological and enzymatic analyses. Our findings reveal basal endoglucanase activity and demonstrate that S. lacrymans employs both hydrolytic and Fenton-like oxidative mechanisms in cellulose degradation. These insights advance the understanding of its decay system and provide a foundation for developing biological control strategies against this highly destructive fungus.

The research explored the effect of dietary rumen-protected betaine (RPB) supplementation on development and function of ileum in Tibetan sheep. Sixty male lambs (17.72 ± 0.19 kg, aged 2 months) were randomly divided into control group (Ctrl) and RPB group (0.08% Bet). The adaptation feeding period was 10 days, and the experimental period was 90 days. Results suggested that dietary RPB significantly increased villus height, villus height-to-crypt depth (VH/CD) ratio, total antioxidant capacity (T-AOC) (P < 0.05), and decreased malondialdehyde (MDA), lipopolysaccharide (LPS), tumor necrosis factor-α (TNF-α) (P < 0.05), as well as altered the composition of short-chain fatty acids (SCFAs). Importantly, expression of ileal barrier-related gene (Claudin-1) was elevated (P < 0.05). Microbial analyses showed RPB supplementation increased the relative abundances of Aeriscardovia and Bifidobacterium. Several differential metabolites, including Cer 18:1;2O/18:0, Cer 18:1;2O/24:2 and (±)13-HpODE, were significantly increased in the RPB group (P < 0.05). The VH/CD was positively correlated with Bifidobacterium, Cer 18:1;2O/18:0, Cer 18:1;2O/24:2 and (±)13-HpODE (r > 0.5). To sum up, our results suggest that the dietary RPB supplementation could affect the ileal SCFA concentration by modulating the microbial community and regulating metabolism, thereby contributing to ileal development and barrier function. This study offers new evidence supporting the use of RPB as a potential application for Tibetan sheep.

This study presents a green nanobiotechnological platform for enhanced L-DOPA biosynthesis. Intracellular tyrosine hydroxylase (TH) was immobilized onto silver nanoparticles (AgNPs) biosynthesized using extract of the edible mushroom Agaricus arvensis and subsequently applied for the aerobic biotransformation of synthetic L-tyrosine. The AgNPs were produced using the mushroom extract as a natural reducing agent and optimized for "TH" activity under controlled conditions: 2.5% (w/v) biomass concentration, peptone-saline medium, 90 °C, and 24 min reaction time. Various analytical techniques such as UV-Vis spectroscopy, SEM, FTIR and XRD were used to confirm the synthesis and characterization of the AgNPs. The particle size was further validated by Scanning Electron Microscopy (SEM), revealing an average size of 88.49 ± 3.83 nm. The particle size was further analyzed by a Zeta-sizer, which showed a Z-average size of 163.7 d.nm. When applied in the biotransformation of synthetic L-tyrosine, the AgNP-immobilized enzyme significantly outperformed the free enzyme, yielding a 2.54-fold increase in L-DOPA production within 1.5 h. These results indicate that Agaricus arvensis-derived AgNPs not only stabilize the enzyme but also boost its activity, providing a sustainable and efficient approach for producing L-DOPA. This method holds promise for large-scale applications in pharmaceutical manufacturing.

Epigallocatechin gallate (EGCG), the predominant catechin in green tea, has limited application due to its poor water solubility and instability. To address these issues, this study utilized recombinant sucrose phosphorylase to catalyze the glucosylation of EGCG, successfully synthesizing (-)-epigallocatechin gallate 4',4″-O-α-D-diglucopyranoside (EGCG-2G). The process was optimized using response surface methodology, achieving a 97.46% conversion rate of EGCG. EGCG-2G was purified to ≥ 99% purity by semi-preparative liquid chromatography. It exhibited approximately 124-fold higher water solubility than EGCG and demonstrated significantly enhanced stability under thermal and acidic conditions (50 °C, pH = 5), with an 84.82% and 35.36% improvement over EGCG and commercial (-)-epigallocatechin-3-gallate-4'-O-α-D-glucoside (EGCG-1G), respectively. Furthermore, EGCG-2G displayed notable antioxidant, anti-inflammatory, and anti-melanogenic activities. It effectively scavenged intracellular and extracellular free radicals, reduced inflammatory cytokine levels, and inhibited melanin synthesis. Molecular docking and gene expression analyses suggested that its anti-melanogenic effect might be associated with the MC1R/cAMP/MITF signaling pathway.