Mei Li

Background: Tuber indicum is a rare edible and medicinal ectomycorrhizal fungus, and the polysaccharide fractions have attracted extensive research attention owing to their potent immunomodulatory potential. Objective/Methods: To systematically characterize the structural features and gut microbiota-mediated immunoregulatory mechanisms of water-extracted polysaccharide (TIWP) and alkali-extracted polysaccharide (TIAP) from T. indicum, two polysaccharide fractions were prepared and comprehensively structurally characterized in this study. Results: The maximum molecular weight of TIWP reached 2.65 × 10⁷ Da, which was dominated by glycosidic linkages of →3)-Glcp-(1→, →2,4)-Glcp-(1→ and →3,6)-Glcp-(1→. TIAP possessed a higher molecular weight up to 3.87 × 10⁷ Da, with predominant glycosidic bonds of →3,6)-Glcp-(1→, →4)-Glcp-(1→ and →2,4)-Glcp-(1→. In vivo bioactivity evaluation results demonstrated that both TIWP and TIAP significantly restored the proportions of CD3⁺ T and CD19⁺ B lymphocyte subsets in peripheral blood and spleen, and alleviated pathological damage in splenic and colonic tissues. Distinct regulatory patterns of gut microbiota were observed between the two polysaccharides: TIWP markedly enriched the genera Lactobacillus and Ruminiclostridium, whereas TIAP elevated the relative abundances of Lactobacillus and Alloprevotella. Untargeted metabolomics combined with KEGG pathway enrichment analysis revealed that TIWP and TIAP activated the pantothenic acid and coenzyme A biosynthesis pathway and the linoleic acid metabolism pathway. Conclusions: Collectively, TIWP and TIAP alleviated CTX-triggered immunosuppression through distinct “gut microbiota-metabolite-immunity” regulatory networks due to their structural disparities. This study provides a theoretical basis for the development of gut microecology-targeted functional foods with immunomodulatory functions.

The global rise in metabolic disorders demands novel interventions targeting starch digestion. This study investigated two dietary phenolic acids (caffeic acid (CA) and p-hydroxycinnamic acid (p-HA)) as inhibitors of α-amylase and α-glucosidase through integrated experimental and computational approaches. Molecular docking showed distinct binding modes, and CA formed stable hydrogen bonds with catalytic residues of α-glucosidase, while p-HA interacted mainly with α-amylase via hydrophobic contacts. Enzyme kinetics revealed concentration-dependent mixed-type inhibition, with CA being more potent against α-glucosidase and p-HA against α-amylase. Spectroscopic analysis indicated both acids induced structural changes in the enzymes, with CA causing greater α-helix reduction (Δ7.03% vs. Δ2.10%) by altering the tryptophan microenvironment. Moreover, both compounds significantly suppress glucose absorption in the proximal small intestine in an ex vivo everted gut sac model, with p-HA exhibiting exceptional efficacy in the duodenum. These findings clarify structure–activity relationships and support the potential use of CA and p-HA as local intestinal agents for modulating carbohydrate absorption.

Suillus luteus is a highly prized edible fungus and demonstrates significant potential in the field of bioremediation, particularly for soil restoration and pollution mitigation. However, systematic research on the structural characteristics of the bioactive polysaccharides and regulatory effects on gut microbiota metabolism remains scarce. In this study, S. luteus polysaccharide (SLP) was obtained by hot water extraction and the structural characteristics were systematically determined, as well as the regulatory function on gut microbiota metabolism in a tumor-bearing mice model. Results showed that SLP exhibited an average molecular weight of approximately 1.90 × 10⁶ Da with Fuc:Man:Glc:Gal molar ratio of 0.37:1.00:0.72:0.54. The polysaccharide predominantly employed β-(1→4)-Manp as the backbone with α-(1→3)-Fucp, α-(1→6)-Glcp, and α-(1→6)-Galp as side chains. SLP administration of 200 mg/kg in tumor-bearing mice exerted enrichment effects of intestinal probiotics, including Lactobacillus and Odoribacter, which were associated with alterations in glyoxylate and dicarboxylic acid metabolism, ultimately enhancing CD4⁺ T cell immunity and resulting in a tumor suppression rate of 53.14%. This study provides a theoretical foundation and supporting data for the development of S. luteus polysaccharide in the functional food field.

With the development of synthetic biology and biotechnology, chassis engineering has become the main means of industrial protein production, but it has been limited by the lack of efficient gene editing methods and effective engineering strategies. Bacillus amyloliquefaciens shows potential for expressing heterologous proteins, but its cells undergo early autolysis, hindering further application. In this study, an autolysis-related prophage gene cluster was rationally deleted by establishing an efficient CRISPR-nCas9 editing process, and the prophage mutant strain was constructed, which prevented cell lysis. Based on the prophage mutant strain, we screened secondary metabolite biosynthetic gene clusters that hindered the expression of heterologous proteins, and we made reasonable deletions to further improve their efficient expression. Finally, an optimized yield of acid-stable α amylase (2,46,089.21 U/mL) was obtained in a 5-L fed-batch fermentation. Therefore, we successfully constructed an ideal candidate strain for the expression of heterologous proteins, which provides an important research basis for the development of more chassis strains.

BACKGROUND: Xanthohumol is an isopentadienyl flavonoid in hops, which have several pharmacological effects. However, due to the poor bioavailability of xanthohumol, it cannot be widely used.RESULT: In this study, solvent extraction combined with preparative liquid chromatography was used to separate and purify xanthohumol in hop residue. And the purity, yield and recovery of xanthohumol was 983.0 ± 2.1 g kg⁻¹, 921.61 ± 5.65 g kg⁻¹, and 5.41 ± 0.07 g kg⁻¹, respectively. Response surface methodology optimization revealed that 216.75 g kg⁻¹ ethyl oleate, 574.1 g kg⁻¹ polyoxyl‐35 castor oil (EL35) and 209.15 g kg⁻¹ polyethylene glycol 200 (PEG200) produced the xanthohumol nanoemulsion with a loading capacity of 85.40 ± 0.33 g kg⁻¹, mean droplet diameter of 42.35 ± 0.06 nm, and zeta potential of −21.78 ± 0.18 mV.CONCLUSION: Xanthohumol nanoemulsion has better relative stability. The relative oral bioavailability of xanthohumol nanoemulsion was increased by 1.76 times. These results provide a theoretical basis for the application of nanoemulsion containing xanthohumol in food and pharmaceutical industry. © 2024 Society of Chemical Industry.

Surgical threads are of great importance to prevent wound infection and accelerate tissue healing in surgical treatment. Cellulose nanofibrils (CNF) and chitosan (CS) are attracting increasing attention to be employed as biomedicine materials due to their nontoxicity, cytocompatibility, and biodegradability. However, a robust and absorbable cellulose-based surgical thread has not been explored. Therefore, in this work, a bioinspired CNF/CS composite thread containing 5% cationic polyacrylamide (CPAM) by the mass of CS was prepared, and the obtained CNF/CS-5C thread exhibited excellent mechanical properties and low swelling ratio in water due to the high cross-link degree. Especially, the tensile strength (1877 ± 107 MPa) of this thread was much higher than that of most reported CNF-based threads. Meanwhile, compared with commercial silk and Vicryl surgical threads, the CNF/CS-5C thread exhibited better in vitro cytocompatibility toward endothelial and fibroblast cells and lower inflammatory response in vivo to subcutaneous tissues of rats. In addition, the obtained thread could be regarded as a promising absorbable suture, which exhibited excellent wound healing performances in vivo. Therefore, the prepared absorbable thread will open a new window to prepare novel and advanced cellulose-based threads for medical applications.

Natural deep eutectic solvents (NDESs) were used to extract flavonoids and polyphenols from lotus (Nelumbo nucifera Gaertn.) leaves at the same time, and the extraction process was optimized to provide reference for the effective development and utilization of lotus leaves. The deep eutectic solvents (DESs) with the highest yield of flavonoids and polyphenols were screened out from 19 different NDES combinations. The response surface method was employed to optimize the extraction process. After a rational design, a lactic acid/glycerol (molar ratio 1:2) DES was chosen as the optimal extraction solvent, and the optimum extraction parameters were as follow: water content (29%), liquid–solid ratio (37:1 mL/g), extraction time (61 min), and extraction temperature (53 °C). Compared with traditional water extraction or ethanol extraction, it improved the yield of flavonoids (126.10 mg/g) and polyphenols (126.10 mg/g). By LC–MS analysis, 19 flavonoids or organic acid compounds with known compound structural formulae were identified in the DES extract of lotus leaves. By comparing the free radical scavenging ability and total reducing ability, the extraction of lotus leaves using the NDES method was superior to both ethanol extraction and water extraction. It is a green, environmentally friendly, and efficient extraction method for antioxidants from leaves of Nelumbo nucifera Gaertn.