Chain conformation, physicochemical properties of fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus and its in vitro fermentation by human gut microbiota

Sea cucumber polysaccharides overcome immunotherapy resistance in tumor-bearing mice via modulation of the gut microbiome

Cancer immunotherapy has been successful in patients with different types of cancers, but its efficacy in treating certain types of colorectal cancer (CRC) is limited. The aim of this study was to explore whether sea cucumber polysaccharides (SCP) could impact resistance to anti-programmed cell death-1 (anti-PD1) immunotherapy of CRC and the role of microbiota in mediating their effects. Mice inoculated with immunotherapy resistant CT-26 CRC cells were pretreated with SCP, followed by treatment with/without the anti-PD1 antibody. SCP alone exhibited no inhibitory effect on tumor growth, but they drastically enhanced the efficacy of anti-PD1 treatment, which alone showed minimal effect on tumor development. Compared to anti-PD1 only treatment, a combination of SCP and anti-PD1 increased CD8+ T cells, especially IFN-γ+ cytotoxic CD8+ T cells, and decreased regulatory CD4+ T cells. SCP modulated gut microbiota and increased the relative abundance of bacteria including Bifidobacterium and Faecalibaculum. A fecal microbiota transplantation experiment showed that the sensitizing effect of SCP was at least partly mediated by microbiota. Furthermore, oral supplementation of Bifidobacterium pseudolongum or Faecalibaculum rodentium recapitulated the beneficial effect of SCP in potentiating anti-PD1 efficacy. Altogether, these findings demonstrated that SCP could be potentially developed as a dietary adjuvant to increase the efficacy of immunotherapy in CRC.

Fucosylated chondroitin sulfate, an intriguing polysaccharide from sea cucumber: past, present, and future

Fucosylated chondroitin sulfate (FCS) is a unique polysaccharide, first described nearly four decades ago, and found exclusively in sea cucumbers. It is a component of the extracellular matrix, possibly associated with peculiar properties of the invertebrate tissue. The carbohydrate features a chondroitin sulfate core with branches of sulfated α-Fuc linked to position 3 of the β-GlcA. FCSs from different species of sea cucumbers share a similar chondroitin sulfate core but the structure of the sulfated α-Fuc branches varies significantly. The predominant pattern consists of a single unit of sulfated α-Fuc, though some species exhibit branches with multiple α-Fuc units. This comprehensive review focuses on four major aspects of FCS. Firstly, we describe the initial approaches to elucidate the structure of FCS using classical methods of carbohydrate chemistry. Secondly, we highlight the impact of two-dimensional NMR methods in consolidating and revealing further details about the structure of FCS. These studies were conducted by various researchers across different countries and involving multiple species of sea cucumbers. Thirdly, we summarize the biological activities reported for FCS. Our survey identified 104 publications involving FCS from 42 species of sea cucumbers, reporting 10 types of biological activities. Most studies focused on anticoagulant and antithrombotic activities. Finally, we discuss future perspectives for studies related to FCS. These studies aim to clarify the evolutionary advantage for sea cucumbers in developing such a peculiar fucosylated glycosaminoglycan. Additionally, there is a need to identify the enzymes and genes involved in the metabolism of this unique carbohydrate.

Marine-Derived Fucose-Containing Carbohydrates: Review of Sources, Structure, and Beneficial Effects on Gastrointestinal Health

Fucose, fucose-containing oligosaccharides, and fucose-containing polysaccharides have been widely applied in the fields of food and medicine, including applications in Helicobacter pylori eradication and renal function protection. Fucose-containing carbohydrates (FCCs) derived from marine organisms such as seaweed, invertebrates, microalgae, fungi, and bacteria have garnered growing attention due to their diverse bioactivities and potential therapeutic applications. Marine-derived FCCs characterized by high fucose residue content and extensive sulfate substitution, including fucoidan, fucosylated chondroitin sulfate, and fucose-rich microbial exopolysaccharides, have demonstrated significant potential in promoting gastrointestinal health. This review describes the unique structural features of FCCs and summarizes their health benefits, including regulation of gut microbiota, modulation of microbial metabolism, anti-adhesion activities against H. pylori and gut pathogens, protection against inflammatory injuries, and anti-tumor activities. Additionally, this review discusses the structural characteristics that influence the functional properties and the limitations related to the activity research and preparation processes of FCCs, providing a balanced perspective on the application potential and challenges of FCCs with specific structures for the regulation of gastrointestinal health and diseases.

Construction and characterization of stable multi-species biofilms formed by nine core gut bacteria on wheat fiber

Microbial aggregation mainly occurs on the intestinal epithelium, mucosal layer and undigested food particles in the gastrointestinal tract (GIT). Undigested food particles are usually insoluble dietary fiber (IDF), which can be easily obtained through daily diet, but there are few studies investigating whether the gut bacteria adhering to undigested food particles can form multi-species biofilms. In this study, we prepared mono- and multi-species biofilms using 18 core gut bacteria via a dynamic fermentation method, and it was found that multi-species composed of nine core gut bacteria (M9) showed the best biofilm formation ability. Cell counts of the nine bacteria in multi-species biofilms were 9.36, 11.85, 10.17, 9.93, 12.88, 11.39, 10.089, 9.06, and 13.21 Log10 CFU mL-1. M9 was tightly connected and regularly stacked on wheat fiber and had larger particle sizes than mono-species biofilms. M9 retained biofilm formation ability under pH and bile salt stresses. A human feces invasion experiment demonstrated that M9 can stably adhere to wheat fiber under the interference of complex gut bacteria, and the M9 multi-species biofilm had positions that can be filled by various gut bacteria. Metabolome results indicated that the M9 multi-species biofilm had more metabolic productions and more complex interspecies interactions than mono-species biofilms. This study provides a dynamic fermentation method to prepare multi-species biofilms on wheat fiber in vitro. It will also offer a research basis for clarifying whether gut bacteria can utilize IDF to form biofilm structures in vivo and the possible interspecific interactions and physiological functions of bacteria in biofilms.

Sulfated Polysaccharides from Sea Cucumber Cooking Liquid Prevents Obesity by Modulating Gut Microbiome, Transcriptome, and Metabolite Profiles in Mice Fed a High-Fat Diet

We aimed to explore the anti-obesity mechanism from the microbiome, metabolome, and transcriptome viewpoints, focusing on the sulfated polysaccharides found in the cooking liquid of Apostichopus japonicus (CLSPAJ) to explore the potential mediators of the anti-obesity effects in mice fed a high-fat diet (HFD). The mice treated with CLSPAJ showed a decrease in obesity and blood lipid levels. Gut microbiome dysbiosis caused by the HFD was reversed after CLSPAJ supplementation, along with increased levels of indole-3-ethanol, N-2-succinyl-L-glutamic acid 5-semialdehyde, and urocanic acid. These increases were positively related to the increased Akkermansia, Lactobacillus, Roseburia, and Phascolarctobacterium. Transcriptome analysis showed that B cell receptor signaling and cytochrome P450 xenobiotic metabolism were the main contributors to the improvement in obesity. Metabolome-transcriptome analysis revealed that CLSPAJ reversal of obesity was mainly due to amino acid metabolism. These findings suggest that CLSPAJ could be a valuable prebiotic preparation for preventing obesity-related diseases.

Purification and Structural Analyses of Sulfated Polysaccharides from Low-Value Sea Cucumber Stichopus naso and Anticoagulant Activities of Its Oligosaccharides

Three polysaccharides (SnNG, SnFS and SnFG) were purified from the body wall of Stichopus naso. The physicochemical properties, including monosaccharide composition, molecular weight, sulfate content, and optical rotation, were analyzed, confirming that SnFS and SnFG are sulfated polysaccharides commonly found in sea cucumbers. The highly regular structure {3)-L-Fuc2S-(α1,}n of SnFS was determined via a detailed NMR analysis of its oxidative degradation product. By employing β-elimination depolymerization of SnFG, tri-, penta-, octa-, hendeca-, tetradeca-, and heptadeca-saccharides were obtained from the low-molecular-weight product. Their well-defined structures confirmed that SnFG possessed the backbone of {D-GalNAc4S6S-β(1,4)-D-GlcA}, and each GlcA residue was branched with Fuc2S4S. SnFS and SnFG are both structurally the simplest version of natural fucan sulfate and fucosylated glycosaminoglycan, facilitating the application of low-value sea cucumbers S. naso. Bioactivity assays showed that SnFG and its derived oligosaccharides exhibited potent anticoagulation and intrinsic factor Xase (iXase) inhibition. Moreover, a comparative analysis with the series of oligosaccharides solely branched with Fuc3S4S showed that in oligosaccharides with lower degrees of polymerization, such as octasaccharides, Fuc2S4S led to a greater increase in APTT prolongation and iXase inhibition. As the degree of polymerization increases, the influence from the sulfation pattern diminishes, until it is overshadowed by the effects of molecular weight.

Updated Progress on Polysaccharides with Anti-Diabetic Effects through the Regulation of Gut Microbiota: Sources, Mechanisms, and Structure-Activity Relationships

Diabetes mellitus (DM) is a common chronic metabolic disease worldwide. The disturbance of the gut microbiota has a complex influence on the development of DM. Polysaccharides are one type of the most important natural components with anti-diabetic effects. Gut microbiota can participate in the fermentation of polysaccharides, and through this, polysaccharides regulate the gut microbiota and improve DM. This review begins by a summary of the sources, anti-diabetic effects and the gut microbiota regulation functions of natural polysaccharides. Then, the mechanisms of polysaccharides in regulating the gut microbiota to exert anti-diabetic effects and the structure-activity relationship are summarized. It is found that polysaccharides from plants, fungi, and marine organisms show great hypoglycemic activities and the gut microbiota regulation functions. The mechanisms mainly include repairing the gut burrier, reshaping gut microbiota composition, changing the metabolites, regulating anti-inflammatory activity and immune function, and regulating the signal pathways. Structural characteristics of polysaccharides, such as monosaccharide composition, molecular weight, and type of glycosidic linkage, show great influence on the anti-diabetic activity of polysaccharides. This review provides a reference for the exploration and development of the anti-diabetic effects of polysaccharides.

Fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus alleviate the intestinal barrier injury and oxidative stress damage in vitro and in vivo

This study aimed to investigate the alleviative effects of fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCSSc) on the intestinal barrier injury and oxidative stress damage in vitro and in vivo. The results showed that fCS-Sc protected the intestinal barrier and improved the antioxidant function in H2O2 damaged Caco-2 cells via up-regulating the tight junction proteins and activating Keap1-Nrf2-ARE antioxidant pathway. Furthermore, administration fCS-Sc could ameliorate the weight loss and spleen index decrease in Cyclophosphamide (Cy) treated mice, improve the expressions of ZO-1, Claudin-1, Nrf2, SOD, and NQO-1 in Cy damaged colon tissue, showing significant protective effects against intestinal barrier damage and oxidative stress in vivo. fCS-Sc intervention also alleviated the gut microbiota disorder though increasing the richness and diversity of intestinal bacteria, regulating the structural composition of gut microbiota. fCS-Sc promoted the relative abundance of beneficial microbiota and inhibited the growth of harmful bacteria. This study provided a theoretical basis for the application of fCS-Sc as a prebiotic in chemotherapy.

Sulfated polysaccharides in sea cucumbers and their biological properties: A review

Sea cucumbers contain a wide range of biomolecules, including sulfated polysaccharides (SPs), with immense therapeutic and nutraceutical potential. SPs in sea cucumbers are mainly fucosylated chondroitin sulfate (FCS) and fucan sulfate (FS) which exhibit a series of pharmacological effects, including anticoagulant activity, in several biological systems. FCS is a structurally distinct glycosaminoglycan in the sea cucumber body wall, and its biological properties mainly depend on the degree of sulfation, position of sulfate group, molecular weight, and distribution of branches along the backbone. So far, FCS and FS have been recognized for their antithrombotic, anti-inflammatory, anticancer, antidiabetic, anti-hyperlipidemic, anti-obesity, and antioxidant potential. However, the functions of these SPs are mainly dependent on the species, origins, harvesting season, and extraction methods applied. This review focuses on the SPs of sea cucumbers and how their structural diversities affect various biological activities. In addition, the mechanism of actions of SPs, chemical structures, factors affecting their bioactivities, and their extraction methods are also discussed.

Active polysaccharides: a new roadmap for the prevention and treatment of food allergy

Active polysaccharides are extensively utilized in the fields of food and medicine because of their rich functional properties and structural plasticity. However, there are still few systematic studies and reviews on active polysaccharides for allergy. Allergy, especially food allergy, occurs frequently around the world and is related to a variety of factors such as age, genetics and dietary habits. Currently in medicine, avoiding allergens and desensitizing can effectively relieve allergy symptoms, but these are difficult to maintain over the long term and come with risks. Based on the supplementation of dietary nutrition to these two treatments, it has been discovered in recent years that the use of active ingredients from natural substances can effectively intervene in allergies. Considering the potential of active polysaccharides in this regard, we systematically characterize the latent patterns of polysaccharides in allergic symptoms and pathogenesis, including the aspects of gut, immunomodulatory, oxidative stress and signaling pathways, as well as the application prospect of them in allergy. It can be found that active polysaccharides have excellent anti-allergic potential, especially from the ocean. We believe that the active polysaccharides are associated with the treatment of allergic diseases, which may provide the benefits to allergy sufferers in the future.

Intervention effects of sulfate glycosaminoglycan from swim bladder against arsenic-induced damage in IEC-6 cells

In this study, a purified macromolecular sulfate glycosaminoglycan whose structural characterization is similar to chondroitin sulfate from the swim bladder of Aristichthys nobilis, named SBSG, was used to explore the intervention effects on arsenic-induced intestinal epithelial cells (IEC-6) damage. Arsenic exposure led to cell membrane rupture, mitochondrial dysfunction, oxidative damage, and down-regulation of tight junction proteins expression. Treatment with SBSG could alleviate arsenic exposure-induced cell damage by decreasing the extracellular lactate dehydrogenase activity and influencing mitochondrial membrane potential, reactive oxygen species level, malondialdehyde content, and anti-oxidative enzyme activity. On the other hand, SBSG could promote nitric oxide production to achieve potential immunoregulation. The Western blot showed that intervention of SBSG mainly could restrain the activation of the JNK signaling pathway and up-regulate the expression of ZO-1 against arsenic-induced cell damage. This study provides a new perspective for understanding the heavy metal detoxification of SBSG on the intestinal and indicates that SBSG could be used as natural antioxidant resistant to heavy metal toxicity.

Fecal fermentation and high-fat diet-induced obesity mouse model confirmed exopolysaccharide from Weissella cibaria PFY06 can ameliorate obesity by regulating the gut microbiota

Obesity associated with diet and intestinal dysbiosis is a worldwide public health crisis, and exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) have prebiotic potential to ameliorate obesity. Therefore, the present study obtained LAB with the ability to produce high EPS, examined the structure of EPS, and explained its mechanism of alleviating obesity by in vivo and in vitro models. The results showed that Weissella cibaria PFY06 with a high EPS yield was isolated from strawberry juice, and pure polysaccharide (PFY06-EPS) was purified by Sephadex G-100. The structural characteristics of PFY06-EPS showed that the molecular weight was 8.08 × 10⁶ Da and composed of α-(1,6)-D glucosyl residues. An in vitro simulated human colon fermentation test demonstrated that PFY06-EPS increased the abundance of Prevotella and Bacteroides. Cell tests confirmed that PFY06-EPS after fecal fermentation inhibited fat accumulation by promoting the secretion of endogenous gastrointestinal hormones and insulin and inhibiting the secretion of inflammatory factors. Notably, PFY06-EPS reduced weight gain, fat accumulation, inflammatory reactions and insulin resistance in a high-fat diet-induced obesity mouse model and improved glucolipid metabolism. PFY06-EPS intervention reversed obesity-induced microflora disorders, such as reducing the Firmicutes/Bacteroides ratio and increasing butyrate-producing bacteria (Roseburia and Oscillibacter), and reduced endotoxemia to maintain intestinal barrier integrity. Therefore, in vivo and in vitro models showed that PFY06-EPS had potential as a prebiotic that may play an anti-obesity role by improving the function of the gut microbiota.

Structure, in vitro digestive characteristics and effect on gut microbiota of sea cucumber polysaccharide fermented by Bacillus subtilis Natto

This study aimed to understand the structural, digestion and fecal fermentation behaviors of sea cucumber polysaccharide fermented by Bacillus subtilis Natto. Results showed that both sea cucumber polysaccharide (SP) and fermented sea cucumber polysaccharide (FSP) were sulfated polysaccharides mainly containing fucose. The physicochemical property, molecular weight, thermal property, and functional groups were no significant difference between SP and FSP, but the microscopic morphology and monosaccharide composition of FSP changed. Both SP and FSP showed similar digestion and fecal fermentation characteristics, that is, they could not be digested by saliva and gastric juice, but could be partially degraded by small intestine. Due to the decomposition of glycosidic bonds after intestinal digestion and fecal fermentation, the relative molecular mass of SP and FSP decreased. In terms of impacts on gut microbiota, Lachnospira, Bacteroides finegoldii, and Bifidobacteriaceae were significantly increased in SP, while Acinetobacter was significantly increased in FSP. This study provides a good understanding of the changes in the structure and digestive characteristics of sea cucumber polysaccharides caused by fermentation. That information will be beneficial for the development and application of new fermented sea cucumber products.

Home-based microbial solution to boost crop growth in low-fertility soil

Soil microbial inoculants are expected to boost crop productivity under climate change and soil degradation. However, the efficiency of native vs commercialized microbial inoculants in soils with different fertility and impacts on resident microbial communities remain unclear. We investigated the differential plant growth responses to native synthetic microbial community (SynCom) and commercial plant growth-promoting rhizobacteria (PGPR). We quantified the microbial colonization and dynamic of niche structure to emphasize the home-field advantages for native microbial inoculants. A native SynCom of 21 bacterial strains, originating from three typical agricultural soils, conferred a special advantage in promoting maize growth under low-fertility conditions. The root : shoot ratio of fresh weight increased by 78-121% with SynCom but only 23-86% with PGPRs. This phenotype correlated with the potential robust colonization of SynCom and positive interactions with the resident community. Niche breadth analysis revealed that SynCom inoculation induced a neutral disturbance to the niche structure. However, even PGPRs failed to colonize the natural soil, they decreased niche breadth and increased niche overlap by 59.2-62.4%, exacerbating competition. These results suggest that the home-field advantage of native microbes may serve as a basis for engineering crop microbiomes to support food production in widely distributed poor soils.

Supplemental N-acyl homoserine lactonase alleviates intestinal disruption and improves gut microbiota in broilers challenged by Salmonella Typhimurium

BACKGROUND

Salmonella Typhimurium challenge causes a huge detriment to chicken production. N-acyl homoserine lactonase (AHLase), a quorum quenching enzyme, potentially inhibits the growth and virulence of Gram-negative bacteria. However, it is unknown whether AHLase can protect chickens against S. Typhimurium challenge. This study aimed to evaluate the effects of AHLase on growth performance and intestinal health in broilers challenged by S. Typhimurium. A total of 240 one-day-old female crossbred broilers (817C) were randomly divided into 5 groups (6 replicates/group): negative control (NC), positive control (PC), and PC group supplemented with 5, 10 or 20 U/g AHLase. All birds except those in NC were challenged with S. Typhimurium from 7 to 9 days of age. All parameters related to growth and intestinal health were determined on d 10 and 14.

RESULTS

The reductions (P < 0.05) in body weight (BW) and average daily gain (ADG) in challenged birds were alleviated by AHLase addition especially at 10 U/g. Thus, samples from NC, PC and PC plus 10 U/g AHLase group were selected for further analysis. S. Typhimurium challenge impaired (P < 0.05) intestinal morphology, elevated (P < 0.05) ileal inflammatory cytokines (IL-1β and IL-8) expression, and increased (P < 0.05) serum diamine oxidase (DAO) activity on d 10. However, AHLase addition normalized these changes. Gut microbiota analysis on d 10 showed that AHLase reversed the reductions (P < 0.05) in several beneficial bacteria (e.g. Bacilli, Bacillales and Lactobacillales), along with increases (P < 0.05) in certain harmful bacteria (e.g. Proteobacteria, Gammaproteobacteria, Enterobacteriaceae and Escherichia/Shigella) in PC group. Furthermore, AHLase-induced increased beneficial bacteria and decreased harmful bacteria were basically negatively correlated (P < 0.05) with the reductions of ileal IL-1β and IL-8 expression and serum DAO activity, but positively correlated (P < 0.05) with the increased BW and ADG. Functional prediction revealed that AHLase abolished S. Typhimurium-induced upregulations (P < 0.05) of certain pathogenicity-related pathways such as lipopolysaccharide biosynthesis, shigellosis, bacterial invasion of epithelial cells and pathogenic Escherichia coli infection of gut microbiota.

CONCLUSIONS

Supplemental AHLase attenuated S. Typhimurium-induced growth retardation and intestinal disruption in broilers, which could be associated with the observed recovery of gut microbiota dysbiosis.

Fucosylated Chondroitin Sulfate against Parkinson's Disease through Inhibiting Inflammation Induced by Gut Dysbiosis

Growing evidence for the importance of the gut-brain axis in Parkinson's disease (PD) has attracted researchers' interest in the possible application of microbiota-based treatment approaches. Using a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model, we looked into the prospect of treating PD with fucosylated chondroitin sulfate obtained from sea cucumbers Isostichopus badionotus (fCS-Ib). We showed that giving fCS-Ib polysaccharide orally greatly reduced the motor deficits, dopamine depletion, and alpha-synuclein increase caused by MPTP in the substantia nigra (SN). It appears that the anti-PD action of fCS-Ib polysaccharide could be attained by squelching inflammation. Glial cell hyperactivation in SN and overproduction of proinflammatory substances in serum could both be suppressed by fCS-Ib polysaccharide injection. The bacterial DNA in fresh colonic feces was submitted to 16S rRNA and untargeted metabolic analyses to confirm the participation of the microbiota-gut-brain axis in the aforementioned interpretation. The findings showed that the MPTP treatment-induced decrease in norank_f_Muribaculaceae and the increase in Staphylococcus were reversed by the administration of fCS-Ib polysaccharide. The NF-κB signaling pathway was shown to be involved in the fCS-Ib polysaccharide-induced anti-inflammation. In conclusion, our research demonstrated for the first time how fCS-Ib polysaccharide combats PD by reducing inflammation caused by gut microbial dysbiosis.

The in vitro fermentation of compound oral liquid by human colonic microbiota altered the abundance of probiotics and short-chain fatty acid production

Compound oral liquid (COL), made from functional herbal foods, has gained immense popularity in China for healthcare. However, the interaction between the nutrients in COL and gut microbiota is still unclear. In our study, the content of total flavonoids, polyphenols, and proteins was increased and the total sugar reduced by crushing raw ingredients to 10 mesh (COL-C). After 24 h incubation with supplemented COL by human gut microbiota, the results of 16S rRNA high-throughput sequencing revealed that Faecalibacterium, Collinsella, Bifidobacterium, Megamonas, Lactobacillus, Phascolarctobacterium, and Dialister were enriched by COL. In particular, the latter three genera were observed to be significantly enriched after incubation with COL-C. Meanwhile, the abundance of Dorea, Clostridium XIVa, and Escherichia/Shigella was inhibited by COL. Moreover, the increased levels of acetate, propionate, and butyrate in COL were jointly contributed by supplementary carbohydrates and the enrichment of short-chain fatty acid (SCFA)-producing bacteria. In summary, our results indicated that the optimized extraction facilitated the nutrients to be dissolved out and enhanced the potential prebiotic effects for promoting the abundance of probiotics, suggesting that the nutrients in COL-C might improve the microbial structure by strengthening the metabolism of beneficial bacteria and restricting the conditioned pathogens more efficiently.

The crushing pretreatment before extraction facilitated the nutrients to dissolve in compound oral liquid and enhanced the prebiotic effects for promoting the abundance of probiotics and short-chain fatty acid synthesis.

Association of human gut microbiota composition and metabolic functions with Ficus hirta Vahl dietary supplementation

Ficus hirta Vahl (FHV), a traditional herbal ingredient of the tonic diet, receives increasing popularity in southern China. However, it is largely unknown that how a FHV diet (FHVD) affects the human gut microbiome. In this exploratory study, a total of 43 healthy individuals were randomized into the FHVD (n = 25) and Control (n = 18) groups to receive diet intervention for 8 weeks. 16S rRNA gene sequencing, metagenomic sequencing and metabolic profile of participants were measured to assess the association between FHV diet and gut microbiome. A preservation effect of Faecalibacterium and enrichment of Dialister, Veillonella, Clostridium, and Lachnospiraceae were found during the FHVD. Accordingly, the pathway of amino acid synthesis, citrate cycle, coenzyme synthesis, and partial B vitamin synthesis were found to be more abundant in the FHVD. In addition, serine, glutamine, gamma-aminobutyric acid, tryptamine, and short-chain fatty acids (SCFAs) were higher after the FHVD. The conjoint analysis of FHV components and in-vitro fermentation confirmed that the improved SCFAs concentration was collectively contributed by the increasing abundance of key enzyme genes and available substrates. In conclusion, the muti-omics analysis showed that the FHVD optimized the structure of the gut microbial community and its metabolic profile, leading to a healthy tendency, with a small cluster of bacteria driving the variation rather than a single taxon.

Dietary compounds in modulation of gut microbiota-derived metabolites

Gut microbiota, a group of microorganisms that live in the gastrointestinal tract, plays important roles in health and disease. One mechanism that gut microbiota in modulation of the functions of hosts is achieved through synthesizing and releasing a series of metabolites such as short-chain fatty acids. In recent years, increasing evidence has indicated that dietary compounds can interact with gut microbiota. On one hand, dietary compounds can modulate the composition and function of gut microbiota; on the other hand, gut microbiota can metabolize the dietary compounds. Although there are several reviews on gut microbiota and diets, there is no focused review on the effects of dietary compounds on gut microbiota-derived metabolites. In this review, we first briefly discussed the types of gut microbiota metabolites, their origins, and the reasons that dietary compounds can interact with gut microbiota. Then, focusing on gut microbiota-derived compounds, we discussed the effects of dietary compounds on gut microbiota-derived compounds and the following effects on health. Furthermore, we give our perspectives on the research direction of the related research fields. Understanding the roles of dietary compounds on gut microbiota-derived metabolites will expand our knowledge of how diets affect the host health and disease, thus eventually enable the personalized diets and nutrients.

Influence of Natural Polysaccharides on Intestinal Microbiota in Inflammatory Bowel Diseases: An Overview

The incidence of inflammatory bowel disease (IBD) has increased in recent years. Considering the potential side effects of conventional drugs, safe and efficient treatment methods for IBD are required urgently. Natural polysaccharides (NPs) have attracted considerable attention as potential therapeutic agents for IBD owing to their high efficiency, low toxicity, and wide range of biological activities. Intestinal microbiota and their fermentative products, mainly short-chain fatty acids (SCFAs), are thought to mediate the effect of NPs in IBDs. This review explores the beneficial effects of NPs on IBD, with a special focus on the role of intestinal microbes. Intestinal microbiota exert alleviation effects via various mechanisms, such as increasing the intestinal immunity, anti-inflammatory activities, and intestinal barrier protection via microbiota-dependent and microbiota-independent strategies. The aim of this paper was to document evidence of NP–intestinal microbiota-associated IBD prevention, which would be helpful for guidance in the treatment and management of IBD.

Sturgeon Chondroitin Sulfate Restores the Balance of Gut Microbiota in Colorectal Cancer Bearing Mice

Chondroitin sulfate (CS) is a well-known bioactive substance with multiple biological functions, which can be extracted from animal cartilage or bone. Sturgeon, the largest soft bone animal with ~20% cartilage content, is a great candidate for CS production. Our recent study confirmed the role of sturgeon chondroitin sulfate (SCS) in reducing colorectal cancer cell proliferation and tumor formation. Here, we further studied the effect of SCS on modulating gut microbiome structure in colorectal cancer bearing mice. In this study, the transplanted tumor mice model was constructed to demonstrate that SCS can effectively halt the growth of transplanted colorectal tumor cells. Next, we showed that SCS significantly altered the gut microbiome, such as the abundance of Lactobacillales, Gastranaerophilales, Ruminiclostridiun_5 and Ruminiclostridiun_6. According to linear discriminant analysis (LDA) and abundance map analysis of the microbial metabolic pathways, the changes in microbial abundance led to an increase of certain metabolites (e.g., Phe, Tyr, and Gly). Fecal metabolome results demonstrated that SCS can significantly reduce the amount of certain amino acids such as Phe, Pro, Ala, Tyr and Leu presented in the feces, suggesting that SCS might inhibit colorectal cancer growth by modulating the gut microbiome and altering the production of certain amino acids. Our results revealed the therapeutic potential of SCS to facilitate treatment of colorectal cancer. This study provides insights into the development of novel food-derived therapies for colorectal cancer.

Effects of Different Land Use Types and Soil Depth on Soil Nutrients and Soil Bacterial Communities in a Karst Area, Southwest China

To reveal the effect of the interactions between soil depth and different land use types on soil nutrients and soil bacterial communities in a karst area, fifty soil samples from five different karst land use types in Huajiang town, Guizhou province, Southwest China were collected, and the soil bacteria were analyzed using high-throughput absolute quantification sequencing. Our results showed that land use types (LUT) and soil depth (SD) significantly influenced the content of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), nitrate nitrogen (NN), ammonium nitrogen (AN) and available soil phosphorus (AP), and pH; further, the interaction of LUT and SD also significantly influenced SOC, NN, NA, AP, and pH. In addition, LUT clearly impacted the Chao1 and Shannon indexes, but, SD and LUT * SD markedly affect Chao1 and Shannon index, respectively. All the soil bacterial communities were significantly different in the five different five land use types according to PERMANOVA. Importantly, Acidobacteria and Proteobacteria were the predominant phyla at soil depths of 0–20 cm and 20–40 cm among all the LUTs. At 0–20 cm, TN, AN, and SOC exerted a strong positive influence on Acidobacteria, but NN exerted a strong negative influence on Acidobacteria; at 20–40 cm soil, TN and AN exerted a strong positive influence on Acidobacteria; TP exerted no marked influence on any of the phyla at these two soil depths. At 0–20 cm of soil depth, we also found that Chao1 index changes were closely related to the TN, SOC, AN, and NN; similarly, Shannon index changes were significantly correlated to the AN, TN, and SOC; the PCoA was clearly related to the TN, SOC, and AN. Interestingly, at soil depth of 20–40 cm, Chao 1 was markedly related to the TN and pH; Shannon was markedly correlated with the SOC, TP, AN, and AP; and the PCoA was significantly correlated with the TN and pH. Our findings imply that soil nutrients and soil bacteria communities are strongly influenced by land use types and soil depth in karst areas.

Holothurian fucosylated chondroitin sulfates and their potential benefits for human health: Structures and biological activities

Fucosylated chondroitin sulfates (FCS) are a sulfated polysaccharide exclusively existing in the body wall of sea cucumber. FCS possesses a mammalian chondroitin sulfate like backbone, namely repeating disaccharides units composed of GlcA and GalNAc, with fucosyl branches linked to GlcA and/or GalNAc residues. It is found that FCS can prevent unhealthy dietary pattern-induced metabolic syndromes, including insulin resistance and β-cell function improvement, anti-inflammation, anti-hyperlipidemia, and anti-adipogenesis. Further studies show that those activities of FCS might be achieved through positively modulating gut microbiota composition. Besides, FCS also show therapeutic efficacy in cancer, HIV infection, and side effects of cyclophosphamide. Furthermore, bioactivities of FCS are closely affected by their molecular weights, sulfation pattern of the fucosyl branches, and chain conformations. This review summarizes the recent 20 years studies to provide references for the future studies and applications of FCS in functional foods or drugs.

Marine Sulfated Polysaccharides: Preventive and Therapeutic Effects on Metabolic Syndrome: A Review

Metabolic syndrome is the pathological basis of cardiovascular and cerebrovascular diseases and type 2 diabetes. With the prevalence of modern lifestyles, the incidence of metabolic syndrome has risen rapidly. In recent years, marine sulfate polysaccharides (MSPs) have shown positive effects in the prevention and treatment of metabolic syndrome, and they mainly come from seaweeds and marine animals. MSPs are rich in sulfate and have stronger biological activity compared with terrestrial polysaccharides. MSPs can alleviate metabolic syndrome by regulating glucose metabolism and lipid metabolism. In addition, MSPs prevent and treat metabolic syndrome by interacting with gut microbiota. MSPs can be degraded by gut microbes to produce metabolites such as short chain fatty acids (SCFAs) and free sulfate and affect the composition of gut microbiota. The difference between MSPs and other polysaccharides lies in the sulfation pattern and sulfate content, therefore, which is very important for anti-metabolic syndrome activity of MSPs. This review summarizes the latest findings on effects of MSPs on metabolic syndrome, mechanisms of MSPs in treatment/prevention of metabolic syndrome, interactions between MSPs and gut microbiota, and the role of sulfate group and sulfation pattern in MSPs activity. However, more clinical trials are needed to confirm the potential preventive and therapeutic effects on human body. It may be a better choice to develop new functional foods containing MSPs for dietary intervention in metabolic syndrome.

Modulation of Gut Microbiota Composition and Short-Chain Fatty Acid Synthesis by Mogroside V in an In Vitro Incubation System

Mogroside V (MV), a sweetener, is one of the major components inSiraitia grosvenorii. In our research, after in vitro incubation with MV for 24 h, the human gut microbiota diversity changed, with an enrichment of the genera Bacteroides, Lactobacillus, Prevotella, Megasphaera, and Olsenella and the inhibition of Clostridium XlVa, Dorea, and Desulfovibrio. Moreover, the synthesis of short-chain fatty acids, such as acetate, propionate, and butyrate, was increased by gut microbiota. According to ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) analysis, MV was decomposed into secondary mogrosides, such as mogroside II/I and mogrol, by gut microbiota. Enhanced antioxidant abilities of the metabolites were found in the broth. The results suggested that MV, as a potential prebiotic, could benefit human health through its interaction with gut microbiota.

Quantitative ecology associations between heterotrophic nitrification-aerobic denitrification, nitrogen-metabolism genes, and key bacteria in a tidal flow constructed wetland

This study explored the quantitative mechanisms of heterotrophic nitrification-aerobic denitrification (HN-AD) in a pilot-scale two-stage tidal flow constructed wetland (TFCW). The TFCW packed shale ceramsite (SC) and activated alumina (AA) at each stage, respectively, and aimed to improve decentralized wastewater treatment efficiency. In start-up phases, AA-TFCW accelerated NH₄⁺-N decline, reaching transformation rates of 6.68 mg NH₄⁺-N/(L·h). In stable phases, SC-AA-TFCW resisted low-temperatures (<13 °C), achieving stable NH₄⁺-N and TN removal with effluents ranging 6.36-8.13 mg/L and 9.43-14.7 mg/L, respectively. The dominant genus, Ferribacterium, was the core of HN-AD bacteria, simultaneously removing NH₄⁺-N and NO₃^--N by nitrate assimilation and complete denitrification (NO₃^--N → N₂), respectively. The quantitative associations highlighted importance of nitrification, nitrate assimilation, and denitrification in nitrogen removal. HN-AD bacteria (e.g., Lactococcus, Thauera, and Aeromonas) carried high-weight genes in quantitative associations, including napAB, nasA and gltBD, implying that HN-AD bacteria have multiple roles in SC-AA-TFCW operation.

Complete mitochondrial genome of a tropical sea cucumber, Stichopus chloronotus

In this study, we report the complete mitochondrial genome of Stichopus chloronotus. The mitogenome was 16,247 base pairs (58.55% A + T content) in length, comprising a total of 37 genes, including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. To resolve the phylogenetic position of S. chloronotus, we analyzed all mitochondrial protein-coding genes from 27 species within the Echinodermata. The results showed that S. chloronotus belonged to the family Stichopodidae and was more closely related to tropical Stichopus species (S. horrens and S. monotuberculatus) than to other species. Our results will be useful for evolutionary analysis of sea cucumber species.

Gut microbiota response to sulfated sea cucumber polysaccharides in a differential manner using an in vitro fermentation model

Sea cucumber Stichopus japonicus has been consumed as high-valued seafood in Asian, and its sulfated polysaccharide (SCSPsj) has been inferred to benefit the host health via modulating gut microbiota composition. The present study compared the responses of gut microbiota communities from different donors to SCSPsj, and the key bacteria were identified by 16S rRNA gene sequencing analysis and in vitro fermentation with specific bacteria. Gut microbiota communities from 6 donors (A ~ F) utilized the polysaccharides to different degrees in vitro fermentation. Further comparison of Samples A and C demonstrated that Sample C with the relatively strong SCSPsj utilization capability possessed more Parabacteroides while Sample A contained more Bacteroides. Further in vitro fermentation of SCSPsj with 10 Parabacteroides and Bacteroides species suggests that Parabacteroides distasonis, enriched in Sample C, plays a critical role in the utilization of the polysaccharides. Moreover, short chain fatty acids and the metabolite profiles of Samples A and C were also compared, and the results showed that more beneficial metabolites were accumulated by the microbiota community consuming more sulfated sea cucumber polysaccharides. Our findings revealed that certain key members of gut microbiota, such as Parabacteroides distasonis, are critical for SCSPsj utilization in gut so as to influence the benefits of the polysaccharide supplement for host. Thus, to obtain better functional outcome for sulfated sea cucumber polysaccharides and sea cucumber, more attention needs to be paid to the effects of inter-individual differences in microbiota community structure.

Prebiotic characteristics of arabinogalactans during in vitro fermentation through multi-omics analysis

BACKGROUND AND OBJECTIVES

Dietary fibers have beneficial effects on human health through the interaction with gut microbiota. Larch wood arabinogalactan (LA-AG) is one kind of complex soluble dietary fibers that may be utilized by human gut microbiota.

METHODS AND RESULTS

In this study, the LA-AG degradation by gut microbiota were characterized by investigating the change of LA-AG, microbiota composition, and the production of short-chain fatty acids (SCFAs), lactic acid, succinic acid, as well as volatile organic metabolites. During the fermentation, pH decreased continuously, along with the organic acids (especially acetic acid and lactic acid) accumulating. LA-AG was degraded by gut microbiota then some beneficial metabolites were produced. In addition, LA-AG inhibited the proliferation of some gut microbiota (Unclassified_Enterobacteriaceae and Citrobacter) and the accumulation of some metabolites (Sulfide and indole) released by gut microbiota.

CONCLUSION

LA-AG was partly fermentable fibers with prebiotic potential for human gut health.

Beneficial Effects of Holothuria leucospilota Polysaccharides on Fermentability In Vivo and In Vitro

This work aimed to investigate the in-vitro and in-vivo fermentation behaviors of Holothuria leucospilota Polysaccharides (HLP) and the impact on mouse liver antioxidant activity. HLP showed excellent fermentability during in vitro experiments, which was characterized by increased levels of total sugar consumption and short-chain fatty acids (SCFAs). During in vitro fecal fermentation, the fucose contents in the HLP fermentation products (0.174 mg/mL) were higher than those of xylose and galactosamine during the first three hours, and fucose disappeared after 24 h. The concentrations of the generated SCFAs increased to 111.13 mmol/mL after in-vitro fermentation at 48 h. After 28 days of oral administration, the SCFA contents that were detected in the feces of mice treated with high HLP doses were significantly higher than those in the feces of mice treated with lower doses and the normal group. In addition, histological observations demonstrated that HLP increased the number of goblet cells without causing hepatocellular injury. Moreover, the increased glutathione peroxidase (GSH-Px) and superoxidase dismutase (SOD) activities and decreased malondialdehyde (MDA) contents in the mouse livers treated with HLP suggested the good performance of HLP with respect to liver antioxidants.

The effects of Fushen Granule on the composition and function of the gut microbiota during Peritoneal Dialysis-Related Peritonitis

BACKGROUND

Peritoneal dialysis (PD) is an acknowledged treatment for patients with irreversible kidney failure. The treatment usually causes peritoneal dialysis-related peritonitis (PDRP), a common complication of PD that can lead to inadequate dialysis, gastrointestinal dysfunction, and even death. Recent studies indicated that Fushen Granule (FSG), a Chinese herbal formula, improves the treatment of PD. However, the mechanism of how FSG plays its role in the improvement is still unclear. Gut microbiota has been closely related to the development of various diseases. We carried out a randomized controlled trial to assess whether FSG can modulate the gut microbiota during PDRP treatment.

METHODS

Forty-two PDRP patients were recruited into the clinical trial, and they were randomly divided into control(CON), probiotics(PRO) or Fushen granule group(FSG). To check whether FSG improve the PD treatment, we assessed the clinical parameters, including albumin(ALB), hemoglobin(HGB), blood urea nitrogen(BUN) and creatinine(CR). Fecal samples were collected before hospitalization and discharge, and stored at -80°C within 1 hour. And we assessed the microbial population and function by applying the 16S rRNA gene sequencing and functional enrichment analysis.

RESULTS

Compared to control group, ALB is improved in both probiotics and FSG groups, while HGB is increased but BUN and CR is reduced in FSG group. Sequencing of 16S rRNA genes revealed that FSG and PRO affected the composition of the microbial community. FSG significantly increased a abundant represented by Bacteroides, Megamonas and Rothia, which was significantly correlated with the improvements in carbohydrate and amino acid metabolism.

CONCLUSIONS

This study demonstrates that FSG ameliorates the nutritional status and improves the quality of life by enriching beneficial bacteria associated with metabolism. These results indicate that FSG as alternative medicine is a promising treatment for patients with PDRP.

Health effects of dietary sulfated polysaccharides from seafoods and their interaction with gut microbiota

Various dietary sulfated polysaccharides (SPs) have been isolated from seafoods, including edible seaweeds and marine animals, and their health effects such as antiobesity and anti-inflammatory activities have attracted remarkable interest. Sulfate groups have been shown to play important roles in the bioactivities of these polysaccharides. Recent in vitro and in vivo studies have suggested that the biological effects of dietary SPs are associated with the modulation of the gut microbiota. Dietary SPs could regulate the gut microbiota structure and, accordingly, affect the production of bioactive microbial metabolites. Because of their differential chemical structures, dietary SPs may specifically affect the growth of certain gut microbiota and associated metabolite production, which may contribute to variable health effects. This review summarizes the latest findings on the types and structural characteristics of SPs, the effects of different processing techniques on the structural characteristics and health effects of SPs, and the current understanding of the role of gut microbiota in the health effects of SPs. These findings might help in better understanding the mechanism of the health effects of SPs and provide a scientific basis for their application as functional food.

Purification, structure and conformation characterization of a novel glucogalactan from Anoectochilus roxburghii

Anoectochilus roxburghii (AR) has been used in food, medicine and ornamental industries for a long time. Anion exchange resin was proposed to purify the sub-fraction of water-extracted AR polysaccharide (ARPP-70), and a homogeneous polysaccharide ARPP-70a was obtained. The structural features of ARPP-70a were characterized using gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, and high performance size exclusion chromatograph coupled with multi-angle laser light scattering (HPSEC-MALLS). The relative weight average molecular weight for ARPP-70a was determined to be 14.8 kDa, and the molar ratio of glucose to galactose was 1.0:3.2. The structure of ARPP-70a was elucidated to be glucogalactan, with backbone comprising β-1,4-linked Galp and some α-1,4-linked Glcp. The conformation characteristics of ARPP-70a were supposed to exist as a random coil chain in 0.1 M NaNO₃ solution. Moreover, in vitro antioxidant activity assays revealed ARPP-70a exhibited appreciable antioxidant potential. To the best of our knowledge, this is the first study to obtain this type of glucogalactan, and provide systematic information on its structural and conformational properties. This study improved the understanding of the physicochemical characteristics of AR polysaccharide, which is beneficial for its further application in food and medicinal industry.

Patterns of Relative and Quantitative Abundances of Marine Bacteria in Surface Waters of the Subtropical Northwest Pacific Ocean Estimated With High-Throughput Quantification Sequencing

Bacteria play a pivotal role in shaping ecosystems and contributing to elemental cycling and energy flow in the oceans. However, few studies have focused on bacteria at a trans-basin scale, and studies across the subtropical Northwest Pacific Ocean (NWPO), one of the largest biomes on Earth, have been especially lacking. Although the recently developed high-throughput quantitative sequencing methodology can simultaneously provide information on relative abundance, quantitative abundance, and taxonomic affiliations, it has not been thoroughly evaluated. We collected surface seawater samples for high-throughput, quantitative sequencing of 16S rRNA genes on a transect across the subtropical NWPO to elucidate the distribution of bacterial taxa, patterns of their community structure, and the factors that are potentially important regulators of that structure. We used the quantitative and relative abundances of bacterial taxa to test hypotheses related to their ecology. Total 16S rRNA gene copies ranged from 1.86 × 10⁸ to 1.14 × 10⁹ copies L^-1. Bacterial communities were distributed in distinct geographical patterns with spatially adjacent stations clustered together. Spatial considerations may be more important determinants of bacterial community structures than measured environmental variables. The quantitative and relative abundances of bacterial communities exhibited similar distribution patterns and potentially important determinants at the whole-community level, but inner-community connections and correlations with variables differed at subgroup levels. This study advanced understanding of the community structure and distribution patterns of marine bacteria as well as some potentially important determinants thereof in a subtropical oligotrophic ocean system. Results highlighted the importance of considering both the quantitative and relative abundances of members of marine bacterial communities.

Effects of Short-Term Dietary Fiber Intervention on Gut Microbiota in Young Healthy People

Gut microbiota are critical to many aspects of human health including immune and metabolic health. Long-term diet influences the community structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how the human gut microbiome responds to short-term intervention with dietary fiber. This study explored the effects of mixed dietary fibers on gut microbiota in young, healthy people. Twelve healthy, young adults participated in a randomized, crossover trial comparing the effects of polyglucan, inulin and resistant malt dextrin on gut microbiota composition and bacterial abundances. During the study, the subjects followed their normal diets without any constraints. Microbial community profiles were determined by absolute quantification 16S rRNA gene amplicon sequencing. Mixed model analysis did not reveal an effect of dietary intervention on microbial community structure. At the genus level, dietary fiber intervention for 4 days significantly promoted the growth of Alloprevotella, Parabacteroides and Parasutterella and inhibited the growth of Adlercreutzia, Anaerovorax, Enterococcus, Intestinibacter and Ruminococcus2 compared with the baseline. Addition of whey albumen powder for 4 days promoted the growth of Corynebacterium, Collinsella, Olsenella and Lactococcus but interfered with the growth of Megasphaera. Our results should be corroborated by randomized clinical trials with large sample size.

Regulation effects of indigestible dietary polysaccharides on intestinal microflora: An overview

The human intestinal contains rich and diverse microbiota that utilizes a variety of polysaccharides. The intestinal microflora extends the metabolic functions of the body, obtaining energy from indigestible dietary polysaccharides. It is not only a highly competitive environment but also a comprehensive collaboration for these polysaccharides, as the microbiota work to maximize the energy harvested from them through the intestine. Indigestible dietary polysaccharides help to manage colon health and host health by affecting the gut microbial population. These polysaccharides also influence the metabolic activity of the intestinal microbiota by stimulating the formation of SCFAs. Most of these metabolic activities affect host physiology because the epithelium absorbs secondary metabolites and end products or transports them to the liver, where they could exert other beneficial effects. This article reviews the carbohydrates existing in the human intestine, the regulating actions of indigestible polysaccharides on intestinal microflora, and the molecular basis of the degradation process of these polysaccharides. PRACTICAL APPLICATIONS: Large deals of researches have shown that indigestible polysaccharides possess an outstanding regulation effect on the intestinal microflora, which indicates that indigestible polysaccharides have the potential to be used as prebiotics in the functional food and pharmaceutical industries. However, it is not clear how gut microbiota metabolizes these dietary polysaccharides, and how the resulting gut metabolites may further affect the intestinal microflora population and metabolism. This paper reviews the indigestible dietary polysaccharides existing in the human intestine, the regulation of polysaccharides on gut microbiota, and the molecular basis of the degradation process of these polysaccharides. This review helps to better understand the relationship between indigestible dietary polysaccharides and intestinal microflora, which will provide powerful evidence for the potential use of these polysaccharides as functional foods.

Fabrication of chondroitin sulfate calcium complex and its chondrocyte proliferation in vitro

Chondroitin sulfate (CS)-calcium complex (CSCa) was fabricated, and the structural characteristics of CSCa and its proliferative bioactivity to the chondrocyte were investigated in vitro. Results suggested calcium ions could bind CS chains forming polysaccharide-metal complex, and the maximum calcium holding capacity of CSCa reached 4.23 %. Characterization of CSCa was performed by EDS, AFM, FTIR, UV, XRD and 1H-NMR. It was found that calcium ions were integrated with CS by binding the sulfate or carboxyl groups. The thermal properties analysis indicated CSCa had a good thermal stability by TGA and DSC. CSCa could interact the calcium-sensing receptor increasing the intracellular calcium ions and influence the cell cycle. The TGF-β1 secretion induced by CSCa could activate the TGF-β/Smads pathway and change the genes associated proliferation expression ultimately leading to the chondrocyte proliferation. This research probably has an important implication for understanding the effect of CSCa on bone care as food supplements.

Immunomodulatory effects of fucosylated chondroitin sulfate from Stichopus chloronotus on RAW 264.7 cells

Sea cucumbers were nutritional food and traditional Chinese medicine. In this study, fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCS-Sc), a potential anticoagulant agent and immunological adjuvant, was investigated for its immune activation effects on RAW 264.7 macrophage for the first time. The results indicated that fCS-Sc could significantly promote the proliferation, the pinocytic activity of RAW 264.7 cells, and the production of NO, TNF-α, IL-1β, and IL-6. The fluorescence labeling assay indicated that fCS-Sc could bind to the macrophage. Moreover, the specific pattern recognition receptor inhibition assays showed that toll-like receptor 4 (TLR4) and TLR2 were involved in the recognition of fCS-Sc. Western blot assays indicated that fCS-Sc could induce degradation of cytoplasm IκB-α, and promotion of NF-κB p65 subunit translocation to nucleus, leading to a functional improvement of macrophage through NF-κB pathway. The results suggested that fCS-Sc might served as a promising candidate of immunomodulator.

Commensal Relationship of Three Bifidobacterial Species Leads to Increase of Bifidobacterium in Vitro Fermentation of Sialylated Immunoglobulin G by Human Gut Microbiota

Sialylated immunoglobulin G (IgG) is an important immunoglobulin in breast milk, but its effect on adult gut microbiota is not yet clear due to digestion by pepsin. Based on our previous IgG protecting study, effects of sialylated IgG on gut microbiota were investigated by in vitro anaerobic fermentation in the present study. It was found that the addition of sialylated IgG could significantly promote the growth of Bifidobacterium. Meanwhile, three bifidobacterial species B. bifidum CCX 19061, Bembidion breve CCX 19041, and B. longum subsp. infantis CCX 19042 were isolated. Furthermore, B. breve CCX 19041 and B. longum subsp. infantis CCX 19042 showed co-culture growth property with B. bifidum CCX 19061 in a sialylated IgG-based medium, which was also supported by changes of free monosaccharides and N-glycan structure. These findings suggest that the increase of Bifidobacterium in vitro fermentation is attributed to the commensal relationship of the three bifidobacterial species by utilizing sugars released from sialylated IgG.

Ultrasonic/microwave-assisted extraction, simulated digestion, and fermentation in vitro by human intestinal flora of polysaccharides from Porphyra haitanensis

In this study, we employed a response surface methodology to optimize the ultrasonic/microwave-assisted extraction (UMAE) conditions of Porphyra haitanensis polysaccharides (PHP), and subjected it to a stimulated in vitro digestion and fermentation model in order to investigate the digestion properties of PHP and the effects on human intestinal flora. The optimum extraction conditions consisted of an extraction time of 29.64 min, extraction temperature of 79.94 °C, and solid-liquid ratio of 1:41.79 g/mL. Under these conditions, the maximum yield of PHP predicted was 20.98%. The ζ-potential and thermal properties analysis verified that PHP was a negatively charged polymer, and possessed good thermal stability. Meanwhile, PHP was not digested in vitro by human saliva, simulated gastric and small intestinal juice. Furthermore, PHP modulated the microbiome structure, mainly increasing the relative abundance of Bacteroides and decreasing in the Escherichia_Shigella group. LEfSe analysis illustrated that Bacteroides, Lachnospiraceae_UCG_006 and Bacteroidales_S24_7_group could serve as potential biomarkers for the PHP supplement. This current study proved that the UMAE method was a highly efficient method to extract PHP to the maximum extent, and also provided insight concerning the stability performance of PHP and its prospects for application as a prebiotics candidate in the functional food industries.

Effects of a β-type glycosidic polysaccharide from Flammulina velutipes on anti-inflammation and gut microbiota modulation in colitis mice

Using the Flammulina velutipes polysaccharide (FVP) extracted from our previous study, herein, we investigated the improvement of this β-type glycosidic polysaccharide in alleviating dextran sodium sulfate-induced ulcerative colitis (UC) in mice.