內(nèi)容: Heparin, a glycosaminoglycan, is a stable source of carbon that supports the growth of microorganisms in the human intestine. It is also a commonly used anticoagulant drug in clinical practice, with significant therapeutic effects. Low molecular weight heparin (LMWH) is a highly active low molecular weight fragment obtained via enzymatic reaction or the chemical degradation of heparin. LMWH has been applied globally in the prevention and treatment of venous thromboembolism in thrombosis patients. Simultaneously, as a potential prebiotic, because of its low molecular weight, LMWH can be well degraded by the gut microbiota to maintain intestinal balance. Enzymatic heparin degradation has recently emerged as a viable disposal method for LMWH preparation; however, only very few benchmark enzymes have been thoroughly described and subjected to protein engineering to improve their properties over the past few years. The commercialization of enzymes will require the development of robustly engineered enzymes that meet the demands of industrial processes. Herein, we report a rational protein engineering strategy that includes molecular dynamic simulations of flexible amino acid mutations and disulfide bond screening. Several Bacteroides thetaiotaomicron heparanase Ⅰ (Bt-HepI) mutants were obtained and screened for high thermal stability. We obtained the Bt-HepID204C/K208C/H189W/Q198R variant, which features a stabilized protein surface structure, with a 1.3-fold increase in catalytic constant/michaelis-menten constant (kcat/Km), a 2.44-fold increase in thermal stability at 50 ℃, and a 1.8-fold decrease in the average molecular weight of LMWH produced at 40 ℃ compared with that seen with Bt-HepIWT. Our study establishes a strategy to engineer thermostable HepI to underpin its industrial applications.

內(nèi)容: The prebiotic effects of hyaluronan (HA) are widely recognized, contributing to improved gut health and immune modulation. Despite its extensive use as dietary supplement, the specific interactions between HA oligosaccharides (o-HAs) and the gut microbiome remain largely unexplored. To investigate its role and metabolic fate in gut homeostasis, 200 mg/day of o-HAs (average molecule weight 1 kDa) were added to an automated computer-controlled SIMulator of the Gastrointestinal tract (SIMGI). The results revealed a significant reshaping of the intestinal flora composition by o-HAs, notably reducing the Firmicutes/Bacteroides ratio. Fermentation of o-HAs by gut microbiota significantly increased the abundance of Bifidobacterium, Prevotellaceae_Prevotella, Dialister, Eubacterium, and Sutterella, but decreased that of Catenibacterium, Oscillospira, Klebsiella, and Citrobacter (P < 0.05). This corresponded with significant enhancements in the content of short-chain fatty acids (SCFAs) such as acetic acid, propionic acid and n-butyric acid, highlighting the significant impact of o-HAs at the genus level. Furthermore, analysis of microbial function predicted the downregulation of pathological events in nine human diseases, particularly infectious ones (parasitic and bacterial). Potential inhibitions were observed in metabolic pathways associated with pentose and glucuronate interconversions as well as cationic antimicrobial peptide resistance. These findings underscore the in vitro prebiotic effects of o-HAs and their potential relevance in managing diverticular diseases or preventing metabolic disorders through the regulation of gut microbiota.

內(nèi)容: Inflammation underlies many chronic diseases, and inflammatory bowel disease (IBD) is a condition characterized by long-term inflammation of the gut. Egg whites have been shown to contain many beneficial active substances. Therefore, we obtained 2 peptides from salted egg white: Val-Val-His-Phe (VF-4) and Asp-Thr-Gln-Ala-Met-Pro-Phe-Arg (DR-8). The sodium dextran sulfate (DSS)-induced mice colitis model was used to evaluate its regulatory effect on colitis in vivo. The results showed that VF-4 and DR-8 improved the clinical symptoms of DSS-induced colitis, attenuated colon tissue damage, inhibited the activation of nuclear factor kappa-B (NF-?κB)/mitogen-activated protein kinase (MAPK)/phosphoinositide 3-kinase-Akt (PI3K-AKT) signaling pathways, and inhibited the expression of inflammatory cytokines. 16S rRNA gene sequencing showed that VF-4 and DR-8 administration increased the relative abundance of intestinal beneficial bacteria including Lactobacillus, Blautia, and down-regulated the relative abundance of inflammation-related bacteria including Acinetobacter, Lachnospiraceae_NK4A136_group, Klebsiella. Moreover, the degree of correlation between pro-inflammatory cytokines and microbiota was as follows: interleukin-6 (IL-6) > tumor necrosis factor-α (TNF-α) > interleukin-1β (IL-1β) > interferon-γ (IFN-γ). In conclusion, this study suggests that salted egg white peptides VF-4 and DR-8 have a significant anti-inflammatory effect in vivo. It also provides a strategy for the treatment of IBD and a new way for the high-value utilization of salted egg white.

內(nèi)容: Due to the rapid development of obesity and related metabolic diseases in the world, it is particularly important to explore the ability of novel materials in regulating obesity. In this study, C57BL/6J obese mice were used as objects, and 16S rRNA gene sequencing and lipidomics techniques were used to explore the regulatory effect and mechanism of the Protaetia brevitarsis ethanol extract (50%, V/V) against obesity. Our results showed that P. brevitarsis extract could significantly reduce the body weight, triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and pro-inflammatory cytokines (tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and interleukin-6 (IL-6)) levels of high-fat diet (HFD)-fed mice. Moreover, the P. brevitarsis extract changed the composition and relative abundance of its gut microbiota, especially increasing Akkermansia muciniphila. Meanwhile, the content of short-chain fatty acids (SCFAs) was increased, especially acetic acid and butyric acid, which leads to a decrease in the synthesis and accumulation of lipids in the liver. Furthermore, the P. brevitarsis extract also induced the difference in lipid synthesis in the liver by down-regulating the mRNA levels of sterol regulatory element binding protein-1C (SREBP-1C), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). Therefore, this research provided preliminary work and reference for the development of P. brevitarsis as a functional food for anti-obesity.

內(nèi)容: High-fat diet (HFD) promotes the imbalance of gut microbiota, contributing to the development of metabolic disorders. Pomegranate juice (PJ) and inulin, as dietary polyphenol and dietary fiber respectively, have been reported to ameliorate diet-induced gut microbiota dysbiosis and metabolic disorders. However, the combined effect of PJ and inulin on HFD-induced metabolic disorders has not been elucidated. In current study, we found that the combination of PJ and inulin prevent HFD-induced obesity, dyslipidemia, and gut microbiota dysbiosis. Moreover, the fecal levels of short-chain fatty acids (SCFAs) produced by inulin were increased after inulin combined with PJ. The levels of pomegranate polyphenol metabolites produced by PJ were also increased after PJ combined with inulin, especially pharmacokinetic analysis showed that the presence of inulin enhance the absorption level of urolithin A. Fecal metabolomic analysis found that PJ combined with inulin alter the metabolic status compared with PJ. It was also showed that the levels of SCFAs and pomegranate polyphenol metabolites among groups were correlated with gut microbiota and metabolic disorders indicators. Our results suggested that PJ combined with inulin prevent HFD-induced metabolic disorders, which may be attributed to the promotion of mutual metabolic transformation and absorption of PJ and inulin by gut microbiota.

內(nèi)容: Ulcerative colitis (UC) is a long-term inflammatory disorder that has evolved into a worldwide challenge. The development of new therapies against UC is imperative as all current therapies for UC are flawed in some way. Thus, the present study aimed to assess the palliative effects of Lactobacillus rhamnosus MP108 on UC in mice and to explore its potential mechanisms. The results showed that L. rhamnosus MP108 ameliorated the symptoms of UC, including preventing body weight loss, disease activity index (DAI) elevation, and colon shortening, and attenuated colonic pathological damage. L. rhamnosus MP108 dramatically increased the number of goblet cells, MUC2 level, and tight junction protein level in the colon and remarkably inhibited epithelial cell apoptosis, thereby strengthening the intestinal barrier. L. rhamnosus MP108 pronouncedly diminished pro-inflammatory cytokine levels and strikingly augmented anti-inflammatory cytokine levels, in turn suppressing inflammation. Furthermore, L. rhamnosus MP108 conspicuously boosted the proportion of short-chain fatty acids (SCFAs) producers in gut microbiota, contributing to increased levels of acetate and butyrate. Therefore, L. rhamnosus MP108 might alleviate UC via improving the intestinal barrier, inhibiting inflammation, and modulating intestinal microbiota.

內(nèi)容: Plant-based milk is rich in polyunsaturated fatty acids, polyphenols and other bioactive compounds. This study investigated the effect of 3 plant-based milk (flaxseed milk, oat milk and soy milk) on the ceftriaxone-induced intestinal disorders, and compared the regulation patterns associated with gut microbiome and metabolome. The results showed plant-based milk alleviated the ceftriaxone caused cecum swelling, colonic tissue damage and intestinal microecological disorders. Meanwhile, administered plant-based milk decreased levels of pro-inflammatory cytokine (tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and oxidative stresses (malondialdehyde (MDA) and myeloperoxidase (MPO) in the colon, as well as increasing the levels of tight junction proteins (Occludin, Claudin-1, and ZO-1) in the colon. Moreover, administration of plant-based milk modulated the intestinal microbiota by promoting the relative levels of beneficial bacteria (Bifidobacterium), and inhibiting the harmful bacteria genus (Enterococcus). Furthermore, plant-based milk treatment significantly modulated glycerophospholipids metabolism (e.g. glycerophosphocholine) and arachidonic acid metabolism (e.g. prostaglandin G2 and arachidonic acid) in the serum. In conclusion, plant-based milk could alleviate antibiotic-related imbalance of barrier function damage, gut microbiota disorders and the reduction of metabolic disorders, which lays a foundation for exploring anti-inflammatory and intestinal micro-ecological approach to plant-based milk.

內(nèi)容: Inoculated fermentation enables rapid fermentation of aquatic products. No studies have been conducted on the lipid profiles of inoculated fermented golden pompano (Trachinotus ovatus). In this study, a lipase-producing Bacillus subtilis with salt tolerance was screened from traditionally fermented golden pompano (TF) and used as a starter culture. Whole-genome sequencing analysis revealed it carries 4 clustered regularly interspaced short vpalindromic repeats structures and 2 genes encoding triacylglycerol lipase. Untargeted lipidomics identified lipid molecules (833) in 6 major classes from B. subtilis SCSMX-2 fermented golden pompano (IF). A total of 28 lipid molecules were upregulated in IF, including phosphatidylcholines (PCs), triacylglycerols (TAGs), and lysophosphatidylcholine. B. subtilis supplementation enhanced the production of polyenyl PCs and medium- and long-chain TAGs. The IF rich in linoleic, docosahexaenoic acids (DHA), and eicosapentaenoic acid were primarily distributed in the sn-2 position of DHA, PC and phosphatidylethanolamine. This research revealed the lipid profiles of IF, providing theoretical basis for the application of B. subtilis in the fermented fish industry.

內(nèi)容: The accumulation of heavy metals in mushrooms has presented a significant risk to human health, underscoring the importance of devising a portable and cost-effective method for detecting heavy metals. Thus, we have developed an electrochemical sensor based on 3-dimensional highly reduced graphene oxide (3D-HRGO) in conjunction with Fe3O4 nanoparticles, enabling the simultaneous quantification of Cd2+, Pb2+, Cu2+, and Hg2+. The 3D-HRGO/Fe3O4 nano-particles material prepared in this study was characterized and confirmed by multiple techniques, then dispersed in a simple and environmental dispersant, consist of 75% ethanol and 0.1% Nafion, and coating on a glass carbon electrode (GCE) to preparing a 3D-HRGO/Fe3O4/GCE sensor. The limit of detection (LOD) of 3D-HRGO/Fe3O4/GCE sensor for Cd2+, Pb2+, Cu2+, and Hg2+ in simultaneous detection were 0.2, 0.6, 0.6, and 0.9 μg/L, respectively. The sensor demonstrates exceptional stability, reproducibility, anti-interference, and recovery rate. Furthermore, the electrochemical sensor was employed to detect heavy metals in actual mushrooms and validated through conventional methodologies. This study represents the pioneering utilization of 3D-HRGO/Fe3O4 as a foundational material for an electrochemical sensor capable of simultaneous detection of multiple metals, thereby advancing the progress of on-site and expeditious detection techniques.

內(nèi)容: Salmonella grows better under aerobic conditions as a facultative anaerobic foodborne pathogenic bacteria. The oxygen-scavenging activity of Lactococcus lactis in the intestinal tract is a promising strategy for preventing Salmonella infection. In this study, the aerobic respiration requirement and preventive mechanism of L. lactis subsp. lactis KLDS 4.0325 in murine models infected by Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) SL1344 were investigated. Results indicate that L. lactis KLDS 4.0325 is capable of aerobic respiratory metabolism in the host intestine when exogenous heme exists, and decrease intestinal oxygen concentration, which in turn trigger autophagy of intestinal cells to reduce S. Typhimurium load, improve gut microbiota composition, alleviate intestinal barrier injury and inflammation response. These results suggest that aerobic respiration L. lactis KLDS 4.0325 can prevent S. Typhimurium infection in a new way in which by restoring intestinal cell hypoxia, maintaining immune balance and regulating intestinal flora.