內(nèi)容: Polygonatum sibiricum?has long been a popular functional food in Asia, known for its anti-inflammatory properties. However, its efficacy in alleviating colitis has yet to be investigated. This study aimed to explore the therapeutic potential of?P. sibiricum?polysaccharides (PSP) in dextran sulfate sodium (DSS)-induced colitis, focusing on the related pyroptosis mechanisms. Scanning electron microscopy (SEM) analysis showed that PSP possesses a smooth surface with no pore structure and a dense, lamellar structure adorned with numerous spherical entities. PSP treatment significantly reduced colitis symptoms and decreased pro-inflammatory cytokines, likely through suppression of the Toll like receptor 4 (TLR4)/nuclear factor κB (NF-κB) signaling pathway. Additionally, PSP attenuated NOD-like receptor protein 3 (NLRP3)/apoptosis-associated speck-like protein containing a CARD (ASC)/Caspase-1/Gasdermin D (GSDMD)-mediated pyroptosis and mitochondria damage in the colon, while enhanced the expression of tight junction and adherens junction proteins. Microbiota sequencing showed that PSP increased the abundance of phylum Bacteroidota and genus such as g_unclassified_f_Muribaculaceae,?Lactobacillus, Clostridia_UCG-014, and Lachnospiraceae_NK4A136_group, while decreased the phylum Proteobacteria and the genus?Enterobacter,?Escherichia-Shigella, and?Blautia. In conclusion, this study demonstrates that PSP exerts the potential therapeutic role against colitis, which was mediated by the regulation of gut microbiota and the inhibition of colonic NLRP3/ASC/Caspase-1/GSDMD signaling pathway.

內(nèi)容: The physicochemical properties, structural characteristics, antioxidant, radioprotective and lipid-lowering activities, as well as the underlying structure-activity relationships of polysaccharides extracted from?Nostoc flagelliforme?grown under normal (WL-EPS-1), salt stress (NaCl-EPS-1) and mixotrophic culture conditions (Glu-EPS-1) were studied. The results demonstrated that WL-EPS-1, NaCl-EPS-1 and Glu-EPS-1 were heteropolysaccharides comprising different proportions of monosaccharides and uronic acid, with different average molecular weights of 0.99 × 103, 1.09 × 103?and 1.18 × 103?kDa, respectively. Their intrinsic viscosity were significantly different, at 24.72, 29.98, and 41.06 dL/g, respectively. The functional groups of polysaccharides were not greatly affected, but the chemical composition, triple-helix structure, chain length and surface morphology were significantly influenced by culture conditions.?In vitro?bioactivity assays showed that the antioxidant activity generally increased in the order of WL-EPS-1 < NaCl-EPS-1 < Glu-EPS-1, while NaCl-EPS-1 had the best radioprotective effect, and Glu-EPS-1 had the best lipid-lowering effect. In addition, the structure-activity relationship of the polysaccharides was analyzed by partial least squares, which revealed that the most important factors affecting the antioxidant, radioprotective and lipid-lowering activities of polysaccharides were viscosity and molecular weight. This study provides a strategy for obtaining high-bioactivity polysaccharides by appropriate regulation of culture conditions, as well as opening new directions for the molecular modification of polysaccharides.

內(nèi)容: Bacterial spores commonly co-exist with vegetative cells, presenting challenges in spore separation and detection. The separation of spores is a crucial process for laboratory research and the detection of spore mechanisms. This study introduced a novel method that leverages the high binding affinity of vancomycin (Van) and ampicillin sodium (Amp) to vegetative cells, integrated with magnetic separation technology, to selectively collect spores from complex environments by eliminating vegetative cells. First, Van/Amp-modified magnetic Fe3O4?nanoparticles (Fe3O4?NPs) were synthesized and characterized. Subsequently, these NPs bound vegetative cells, forming magnetic conjugates that could be efficiently removed using a magnetic field. Concurrently, spores were collected with an efficiency exceeding 95%, completing the entire process within 30 min and achieving a spore separation efficiency of up to 105?CFU/mL. This method was successfully applied to actual samples, including tap water and milk. The state of the collected spores was confirmed using Raman spectroscopy and microscopic techniques, verifying that their characteristics matched those of typical spores. The proposed novel method for rapid spore separation, leveraging the "remove bacterial effect" facilitated by Van/Amp-Fe3O4?NPs, showed outstanding spore collection capabilities while preserving the excellent physiological state of spores.

內(nèi)容: Pseudomonas fluorescens?is a widespread spoilage bacterium in food, and its spoilage characteristics and biofilm formation are regulated by?N-acyl-homoserine lactone (AHLs) quorum sensing (QS) system. Quorum quenching (QQ) is considered as an effective strategy to control the spoilage bacteria. Therefore, this study revealed a new QQ bacteria?Lactiplantibacillus plantarum?YP4-1-2. Notably, the crude cell extract (CCE) from?L.?plantarum?YP4-1-2 showed strongly QQ activity against the AHLs of?P.?fluorescens.?The degradation rate of AHLs (N-octanoyl-L-homoserine lactone) reached 25.90%, 78.57% and 100% at the CCE protein concentrations of 57, 86 and 114 μg/mL, respectively. In addition, the CCE could drastically reduce the formation of biofilm, bacterial motility (swimming and swarming), and the release of extracellular protease and biogenic amines of?P.?fluorescens. Real-time polymerase chain reaction (PCR) results revealed that the CCE downregulated QS-related genes (rhlI,?rhlR,?aprX,?algA,?orm,?flgA, and?ldcA). Finally, using whole-genome sequencing analysis, the active substance in the CCE was identified to be penicillin V acylase (PVA) and named?LpPVA. Meanwhile, homologous modeling and molecular docking analysis showed that the binding effect of?LpPVA on long-chain AHLs was better than that on short-chain AHLs. This study demonstrated that?L.?plantarum?YP4-1-2 could be considered as a promising QS inhibitor and antibiofilm agent against foodborne spoilage bacteria.

內(nèi)容: The potential of a plant sterol food supplement (PS-FS) in addressing intestinal inflammation?in vivo?and?in vitro?was evaluated. As?in vivo?model, C57BL/6J mice were exposed to 1.5% dextran sulfate sodium in three 5-day periods, with 10-day rest intervals in between, daily reciving PS-FS (35 mg PS/kg body weight). The?in vitro?approach involved a bi-cameral system with 8-day-differentiated Caco-2 (apical) and RAW264.7 cells (basolateral). The bioaccessible fraction of PS-FS, obtained after INFOGEST 2.0 simulated gastrointestinal digestion, was added to the apical part (90 min), followed by stimulation with lipopolysaccharide (1 μg/mL, 24 h). PS-FS alleviated rectal bleeding and rebalanced pro- (tumor necrosis factor α, interleukin (IL)-6, and IL-8) and anti-inflammatory cytokines (IL-10). Additionally, PS-FS ameliorated histopathological damage and enhancing occludin expression. A reduction in oxidative stress was evidenced by decreased myeloperoxidase activity and reactive oxygen species production. The anti-inflammatory mechanism included suppressing cyclooxygenase 2 expression, reducing prostaglandin E2?production, and inhibiting the phosphorylation and nuclear translocation of the nuclear factor κB p65 subunit. This study reveals the potential of PS-FS as a therapeutic intervention for colitis. The alignment between?in vivo?and?in vitro?outcomes substantiates the appropriateness of the co-culture model to evaluate the anti-inflammatory activity of foods.

內(nèi)容: In the food industry, bacterial cells usually adhere to equipment surfaces, forming biofilms that may cause persistent contamination. This study aimed to identify the key genes responsible for the stronger biofilm-forming capability of the?Listeria monocytogenes?LMB 33426 strain compared to that of the?L.?monocytogenes?CICC 21662 strain through comparative genomics. Additionally, the expression of genes and related metabolic pathways of LMB 33426 and CICC 21662 strains were analyzed at the transcriptional level by high-throughput sequencing technology to uncover key differentially expressed genes between planktonic and biofilm cells of those two strains. Subsequently, the key genes found to present differences that were uncovered by those genome-wide and transcriptomic analyses were used to construct gene deletion strains. The crystalline violet assay and motility assay showed that GL002291, GL002712 and?lmo1438?genes were involved in the regulation of biofilm formation as well as motility. The hydrophobicity and auto-aggregation ability assay results demonstrated an association between the?clpB,?lmo1438, and?lmo0294?genes and bacterial adhesion. However, no significant differences were found regarding this association in the GL002291 and GL002712 genes. This study elucidates some potential regulatory genes associated with biofilm formation in?L.?monocytogenes, and laying a theoretical foundation for future research.

內(nèi)容: Probiotics have been demonstrated to be effective and safe for hyperuricemia (HUA) and gout treatment. Hence, identifying microbes with high uric acid- or purine-metabolizing ability is highly important. Due to the high load of uric acid in chicken feces, we hypothesized that the chicken gut would be an excellent source for new uric acid or purine-metabolizing microbes. In this study, we examined chicken gut contents to isolate an?Enterococcus faecalis?strain (designated CML390) that displayed high uric acid-degrading ability.?In vitro?experiments indicated that?E. faecalis?CML390 could effectively metabolize uric acid under both aerobic and anaerobic conditions, and the richer the nutrients, the higher the rate of uric acid degradation. By integrating genomics, transcriptomics, and metabolomics analyses, we revealed two pathways involved in aerobic and anaerobic uric acid degradation, respectively, in this isolate.?E. faecalis?CML390 relies on oxygen to metabolize uric acid into substances such as allantoin under aerobic conditions, while it also harbors a conserved uric acid-inducible gene cluster for anaerobic uric acid metabolism. An?in vivo?experiment showed that gavage with live?E. faecalis?CML390 in a mouse model of HUA (established using a combination of uric acid and potassium oxonate) significantly reduced serum uric acid levels and alleviated HUA. Our findings contribute to the exploration of the pathways and mechanisms of uric acid metabolism in intestinal microorganisms and provide a candidate probiotic for the treatment of HUA and gout.

內(nèi)容: The global burden of non-alcoholic steatohepatitis (NASH) is on the rise. Researchers recognize inhibiting ferroptosis, a form of cell death leading to iron-dependent oxidative damage, as a promising therapy for treating NASH. Lycopene, a natural antioxidant compound, exhibits various pharmacological properties. However, the anti-NASH efficacy of the dietary recommended concentration of lycopene and the role of lycopene in combating ferroptosis in NASH have remained unclear. Our study investigated lycopene’s impact on ferroptosis in various diet-induced mouse NASH models and corresponding cellular models, unveiling its anti-inflammatory and anti-fibrotic effects. Our findings demonstrated that lycopene notably reduced ferroptosis in methionine- and choline-deficient (MCD) diet-fed mice and a normal mouse hepatocyte cell line (NCTC1469) by restoring balanced ferrous iron levels, lipid reactive oxygen species, and normal mitochondrial morphology. These effects were linked to the regulation of ferroptosis markers glutathione peroxidase 4 (GPX4) and prostaglandin G/H synthase 2. Additionally, lycopene’s anti-ferroptosis action was validated in mice fed a high-fat, high-cholesterol diet and HepG2 cells treated with free fatty acid. Our transcriptomic analysis highlighted peroxisome proliferator-activated receptor α (PPARα) as a primary target of lycopene, crucial for activating the glutathione system because GW6471, a PPARα antagonist, blocked lycopene-induced GPX4 activation. Furthermore, nuclear factor erythroid 2-related factor 2 (Nrf2) played a crucial role in lycopene’s impact on iron metabolism-related proteins ferritin heavy chain 1 and transferrin receptor 1. Notably, when inhibiting PPARα or Nrf2 in MCD diet-fed mice by GW6471 or ML385, lycopene’s protective effects against ferroptosis and NASH progression diminished. These findings underscore the crucial role of PPARα-mediated glutathione system activation and Nrf2-mediated iron metabolism modulation in lycopene’s anti-ferroptosis effects.

內(nèi)容: Algal polysaccharides are an essential active substance in food nutrition and even pharmaceutical activity research due to wide sources, low toxicity, and no side effects. In our previous research, we identified the chemical structure and studied the immunomodulatory mechanism of the polysaccharide from edible green algae?Caulerpa racemosa?var.?peltata?(CRVP). In this study, we further investigated the cytotoxicity and potential mechanism of CRVP against Hepa1-6 cells. Metabolomics analysis showed that CRVP might affect glutathione metabolism-related pathways. CRVP significantly up-regulated oxidized glutathione (GSSG) and down-regulated reduced glutathione (GSH) in Hepa1-6 cells, increasing the ratio of GSSG to GSH and intracellular reactive oxygen species. The potential anti-liver cancer mechanism is that CRVP may affect redox homeostasis and lead to apoptosis by inhibiting glutathione reductase or System Xc–. Based on the known immunomodulatory mechanism of CRVP, this study can provide a material basis for adjuvant therapeutic nutritional agents with immune-enhancing anti-cancer activity.

內(nèi)容: Microbial food is an important direction of sustainable food development in the future. Microorganisms such as lactic acid bacteria (LAB) are important sources of natural radioprotectors. Moderate environmental stress can induce stress response and improve biological activity of LAB. In the previous study,?Lactococcus lactis?subsp.?lactis?IL1403 (L. lactis?IL1403) cell-free extract induced by ionizing radiation (IR) of 500 Gy (IR-CFE) presented the stronger radioprotective effect than untreated cell-free extract in mice. To explore the radioprotective active substances of IR-CFE, the key protein was screened by proteomics and its radioprotective effect?in vivo?was further evaluated. The Kyoto Encyclopedia of Genes and Genomes (KEGG)enrichment showed that two-component systems (TCS) were enhanced to adapt the IR induction. Meanwhile, the protein LlrG belonged to TCS was screened by the protein-protein interaction. Furthermore, the recombinant protein LlrG (rLlrG) could markedly alleviate the?60Coγ-induced damage to the hematopoietic system, oxidative stress and inflammation in mice, thereby exerting its radioprotective function. These results suggested LlrG protein not only played an important role in the adaptation of?L. lactis?IL1403 to IR environment, but also exerted a good radioprotective effect, which could be applied in the development of protein-based radioprotectors.