Effects of berberine hydrochloride on antioxidant response and gut microflora in the Charybdis japonica infected with Aeromonas hydrophila.

This study used berberine hydrochloride to treat the Asian paddle crab, Charybdis japonica infected with the Gram-negative bacterium Aeromonas hydrophila at concentrations of 0, 100, 200 and 300 mg/L. The effect of berberine hydrochloride on the survival rate and gut microbiota of C. japonica was investigated. Berberine hydrochloride improved the stability of the intestinal flora, with an increase in the abundance of probiotic species and a decrease in the abundance of both pathogenic bacteria after treatment with high concentrations of berberine hydrochloride. Berberine hydrochloride altered peroxidase activity (POD), malondialdehyde (MDA), and lipid peroxidation (LPO) in the intestinal tract compared to the control. Berberine hydrochloride could modulate the energy released from the enzyme activities of hexokinase (HK), phosphofructokinase (PFK), and pyruvate kinase (PK) in the intestinal tract of C. japonica infected with A. hydrophila. Zona occludens 1 (ZO-1), Zinc finger E-box binding homeobox 1 (ZEB1), occludin and signal transducer, and activator of transcription5b (STAT5b) expression were also increased, which improved intestinal barrier function. The results of this study provide new insights into the role of berberine hydrochloride in intestinal immune mechanisms and oxidative stress in crustaceans.

Fermented bile acids improved growth performance and intestinal health by altering metabolic profiles and intestinal microbiome in Micropterus salmoides.

A type of fermented bile acids (FBAs) has been produced through a biological method, and its effects on growth performance, metabolism, and intestinal microbiota in largemouth bass were investigated. The results demonstrated that incorporating 0.03 %-0.05 % FBAs diet could improve the final weight, weight gain and specific growth rate, and decrease the feed conversion ratio. Dietary FBAs did not significantly affect the levels of high-density lipoprotein, low-density lipoprotein, and triglycerides, but decreased the activities of α-amylase in most groups. Adding FBAs to the diet significantly increased the integrity of the microscopic structure of the intestine, thickened the muscular layer of the intestine, and notably enhanced its intestinal barrier function. The addition of FBAs to the diet increased the diversity of the gut microbiota in largemouth bass. At the phylum level, there was an increase in the abundance of Proteobacteria, Firmicutes, Tenericutes and Cyanobacteria and a significant decrease in Actinobacteria and Bacteroidetes. At the genus level, the relative abundance of beneficial bacteria Mycoplasma in the GN6 group and Coprococcus in the GN4 group significantly increased, while the pathogenic Enhydrobacter was inhibited. Meanwhile, the highest levels of AKP and ACP were observed in the groups treated with 0.03 % FBAs, while the highest levels of TNF-α and IL-10 were detected in the group treated with 0.04 % FBAs. Additionally, the highest levels of IL-1ß, IL-8T, GF-ß, IGF-1, and IFN-γ were noted in the group treated with 0.06 % FBAs. These results suggested that dietary FBAs improved growth performance and intestinal wall health by altering lipid metabolic profiles and intestinal microbiota in largemouth bass.

Improved diagnostic efficiency of CRC subgroups revealed using machine learning based on intestinal microbes.

BACKGROUND: Colorectal cancer (CRC) is a common cancer that causes millions of deaths worldwide each year. At present, numerous studies have confirmed that intestinal microbes play a crucial role in the process of CRC. Additionally, studies have shown that CRC can be divided into several consensus molecular subtypes (CMS) based on tumor gene expression, and CRC microbiomes have been reported related to CMS. However, most previous studies on intestinal microbiome of CRC have only compared patients with healthy controls, without classifying of CRC patients based on intestinal microbial composition. RESULTS: In this study, a CRC cohort including 339 CRC samples and 333 healthy controls was selected as the discovery set, and the CRC samples were divided into two subgroups (234 Subgroup1 and 105 Subgroup2) using PAM clustering algorithm based on the intestinal microbial composition. We found that not only the microbial diversity was significantly different (Shannon index, p-value < 0.05), but also 129 shared genera altered (p-value < 0.05) between the two CRC subgroups, including several marker genera in CRC, such as Fusobacterium and Bacteroides. A random forest algorithm was used to construct diagnostic models, which showed significantly higher efficiency when the CRC samples were divided into subgroups. Then an independent cohort including 187 CRC samples (divided into 153 Subgroup1 and 34 Subgroup2) and 123 healthy controls was chosen to validate the models, and confirmed the results. CONCLUSIONS: These results indicate that the divided CRC subgroups can improve the efficiency of disease diagnosis, with various microbial composition in the subgroups.

Alteration of the gut microbial composition of critically endangered Malayan tigers (Panthera tigris jacksoni) in captivity during enrichment phase.

BACKGROUND: Enrichment activities may influence the microbiomes of captive tigers', affecting their health, digestion, and behavior. Currently, there are few studies that address the impact of enrichment activity on tigers' health. This study aimed to determine the diversity of the gut microbiome in captive Malayan tigers at Zoo Melaka and Night Safari during the environmental enrichment phase using a metabarcoding approach. METHODS AND RESULTS: This study utilized different enrichment activities which catered for food, sensory, and cognitive enrichment. Eleven fresh fecal samples from captive Malayan tigers at Zoo Melaka and Night Safari were collected under different conditions. All samples were extracted and 16S rRNA V3-V4 region amplicon sequencing was used to characterize the gut microbiome of captive Malayan tigers subjected to various enrichment activities. Firmicutes, Actinobacteriota, and Fusobacteriota were the dominant phyla observed in the gut microbiome of captive Malayan tigers during enrichment activities. This study revealed ß-diversity significantly varied between normal and enrichment phase, however no significant differences were observed in α-diversity. This study demonstrates that environmental enrichment improves the gut microbiome of Malayan tigers because gut microbes such as Lachnoclostridium, which has anti-inflammatory effects and helps maintain homeostasis, and Romboutsia, which has a probiotic effect on the gut microbiome. CONCLUSIONS: This study provides valuable insights into the effects of enrichment activities on the gut microbiome of captive Malayan tigers, offering guidance for enhancing captive management practices aimed at promoting the health and well-being of Malayan tiger in captivity.

Intestinal microbial community well explain larval growth than feed types.

Black soldier fly larvae (BSFL) are considered a sustainable ingredient in livestock feed. However, addressing issues related to feed substrate and intestinal microbiota is essential to ensure optimal larval development. The aim of this study was to assess and elucidate the contribution of substrate nutrients and intestinal microbes to protein and fat synthesis in BSFL. The results showed that larvae that were fed high-quality feed (chicken feed) had high fat biomass, while larvae that were fed medium-quality feed (wheat bran) had high protein biomass. These results indicate that the original nutritional content of the feed cannot fully explain larval growth and nutrient utilization. However, the phenomenon could be explained by the functional metabolism of intestinal microbes. Chicken feed enhanced the fatty acid metabolism of middle intestine microorganisms in larvae within 0-7 days. This process facilitated larval fat synthesis. In contrast, wheat bran stimulated the amino acid metabolism in posterior intestine microorganisms in larvae within 4-7 days, leading to better protein synthesis. The findings of this study highlight the importance of the microbial functional potential in the intestine in regulating protein and lipid synthesis in BSFL, which is also influenced by the type of feed. In conclusion, our study suggests that both feed type and intestinal microbes play a crucial role in efficiently converting organic waste into high-quality insect protein and fat. Additionally, a mixed culture of chicken feed and wheat bran was found to be effective in promoting larval biomass while reducing feed costs. KEY POINTS: • Intestinal microbes explain BSFL growth better than feed substrates. • Chicken feed promotes fatty acid synthesis in the middle intestine • Wheat bran promotes amino acid synthesis in the posterior intestine.

Interactions between human norovirus and intestinal microbiota/microbes: A scoping review.

Human norovirus (HuNoV) is an important foodborne virus, which causes non-bacterial acute gastroenteritis and is associated with a high disease burden. Recently, researchers have focus on the interaction between HuNoV and intestinal microbiota/microbes and engaged in studies investigating the implications of this interaction on HuNoV infection. However, the interaction mechanism and the implication of this interaction on host remain obscure. Current scoping review aimed to systematically investigate the interaction between HuNoV and intestinal microbiota, as well as their implication on HuNoV or HuNoV related symptoms. We found that HuNoV could bind to intestinal microbes and affect the intestinal microbial composition, diversity, and microbial gene expression. In reverse, intestinal microbes could affect HuNoV infectivity, although demonstrating contradictory effects (i.e., promote or inhibit HuNoV replication). These contradictory effects existed among microbes, in part, could be attributed to the differences among microbes (histo-blood group antigens and/or other small molecule substances). Results of current scoping review could assist in the selection and isolation of potential microbial candidates to prevent and/or alleviate HuNoV related symptoms.

The health benefits of dietary polyphenols on pediatric intestinal diseases: Mechanism of action, clinical evidence and future research progress.

Pediatric intestinal development is immature, vulnerable to external influences and produce a variety of intestinal diseases. At present, breakthroughs have been made in the treatment of pediatric intestinal diseases, but there are still many challenges, such as toxic side effects, drug resistance, and the lack of more effective treatments and specific drugs. In recent years, dietary polyphenols derived from plants have become a research hotspot in the treatment of pediatric intestinal diseases due to their outstanding pharmacological activities such, as anti-inflammatory, antibacterial, antioxidant and regulation of intestinal flora. This article reviewed the mechanism of action and clinical evidence of dietary polyphenols in the treatment of pediatric intestinal diseases, and discussed the influence of physiological characteristics of children on the efficacy of polyphenols, and finally prospected the new dosage forms of polyphenols in pediatrics.

Identification of FtfL as a novel target of berberine in intestinal bacteria.

BACKGROUND: Berberine (BBR) is a commonly used anti-intestinal inflammation drug, and its anti-cancer activity has been found recently. BBR can intervene and control malignant colorectal cancer (CRC) through intestinal microbes, but the direct molecular target and related mechanism are unclear. This study aimed to identify the target of BBR and dissect related mechanisms against the occurrence and development of CRC from the perspective of intestinal microorganisms. RESULTS: Here, we found that BBR inhibits the growth of several CRC-driving bacteria, especially Peptostreptococcus anaerobius. By using a biotin-conjugated BBR derivative, we identified the protein FtfL (formate tetrahydrofolate ligase), a key enzyme in C1 metabolism, is the molecular target of BBR in P. anaerobius. BBR exhibits strong binding affinity and potent inhibition on FtfL. Based on this, we determined the crystal structure of PaFtfL (P. anaerobius FtfL)-BBR complex and found that BBR can not only interfere with the conformational flexibility of PaFtfL tetramer by wedging the tetramer interface but also compete with its substrate ATP for binding within the active center. In addition, the enzymatic activities of FtfL homologous proteins in human tumor cells can also be inhibited by BBR. CONCLUSIONS: In summary, our study has identified FtfL as a direct target of BBR and uncovered molecular mechanisms involved in the anti-CRC of BBR. BBR interferes with intestinal pathogenic bacteria by targeting FtfLs, suggesting a new means for controlling the occurrence and development of CRC.

Fecal metabonomics combined with 16S rDNA sequencing to analyze the changes of gut microbiota in rats fed with different protein source diets.

PURPOSE: When blended, animal and plant proteins can complement each other in terms of amino acid composition and release time. In this study, we investigated whether the blended protein diet has a better feeding effect than the single protein diet, and to reveal the differences in growth and intestinal microbiota composition caused by the blended protein diet. METHODS: Forty Sprague Dawley (SD) rats received diets with different protein sources, including casein (C), whey protein (WP), black soybean protein (BSP), and black soybean-whey blended protein (BS-WP), for eight weeks. To investigate the effects of blended protein supplement on gut microbiota and metabolites, we performed a high throughput 16S rDNA sequencing and fecal metabolomics profiling. In addition, we determined growth and serum biochemical indices, and conducted intestinal morphology analyses. RESULTS: Compared to those in the BSP and WP groups, the daily body weight gain and feed conversion efficiency increased in the BS-WP group. Serum biochemical indices indicated that the protein utilization efficiency of the WP and BS-WP groups was relatively high, and the BS-WP blended protein diet improved the protein adoption rate. The BS-WP blended protein diet also improved intestinal tissue morphology and promoted intestinal villi development compared to the single protein diets. Furthermore, dietary protein altered the composition of gut microbiota, the gut microbial diversity of rats fed with the BS-WP diet was significantly (P < 0.05) higher than that of the other groups. The difference in dietary protein corresponded with an alteration of fecal amino acids and their metabolites, and tryptophan and tyrosine metabolism were the key mechanisms leading to the changes in fecal microbial composition. CONCLUSION: Dietary protein sources played an important role in the growth and development of rats by influencing intestinal metabolism and microbial composition. The BS-WP blended protein diet was more conducive to nutrient absorption than the single protein diet. Furthermore, blended protein increased the diversity of intestinal microbes and aided the establishment of intestinal barrier function.

Effects of nutritional therapy on gastrointestinal microbial digestion and barrier defense markers in elderly patients with diabetes.

OBJECTIVE: We sought to investigate the effects of gastrointestinal nutrition therapy on gastrointestinal microbial digestion and barrier defense markers in elderly patients with diabetes. METHODS: A total of 120 elderly patients with type 2 diabetes were enrolled at our hospital between January 2020 and December 2022. The participants in this study were randomly allocated into either the nutritional group (n = 60) who underwent gastrointestinal nutrition therapy or the control group (n = 60) who underwent conventional T2DM diet management for a period of 12 weeks. Clinical data, as well as small intestinal permeability measured by the lactulose-mannitol urine test, plasma circulating IL-6 and zonulin levels measured by ELISA, and expressions of ZO-1 and Claudin-3 in blood analyzed through Western blotting were collected. RESULTS: The nutrition group demonstrated a higher proportion of patients achieving HbA1c < 7% compared to the control group (P < 0.05). Moreover, the nutrition group exhibited a greater reduction in fasting and postprandial blood glucose levels compared to the control group (P < 0.05). The concentrations of formate-tetrahydrofolate ligase and acetic CoA transferase were significantly increased in the nutrition group compared to the control group (P < 0.05). Fecal analysis revealed higher levels of acetic acid and butyric acid in the nutrition group compared to the control group (P < 0.05). The ratio of lactulose to mannitol was higher in the nutrition group compared to the control group (P < 0.05). Furthermore, the nutrition group showed lower levels of IL-6 and zonulin compared to the control group (P < 0.05). CONCLUSION: Personalized gastrointestinal nutrition therapy was found to enhance the production of short-chain fatty acids and preserve intestinal permeability, leading to improved gastrointestinal microbial digestion and barrier defense in elderly patients with diabetes.

Research Progress Regarding the Effect and Mechanism of Dietary Polyphenols in Liver Fibrosis.

The development of liver fibrosis is a result of chronic liver injuries may progress to liver cirrhosis and liver cancer. In recent years, liver fibrosis has become a major global problem, and the incidence rate and mortality are increasing year by year. However, there are currently no approved treatments. Research on anti-liver-fibrosis drugs is a top priority. Dietary polyphenols, such as plant secondary metabolites, have remarkable abilities to reduce lipid metabolism, insulin resistance and inflammation, and are attracting more and more attention as potential drugs for the treatment of liver diseases. Gradually, dietary polyphenols are becoming the focus for providing an improvement in the treatment of liver fibrosis. The impact of dietary polyphenols on the composition of intestinal microbiota and the subsequent production of intestinal microbial metabolites has been observed to indirectly modulate signaling pathways in the liver, thereby exerting regulatory effects on liver disease. In conclusion, there is evidence that dietary polyphenols can be therapeutically useful in preventing and treating liver fibrosis, and we highlight new perspectives and key questions for future drug development.

Rehmannia glutinosa polysaccharides attenuates colitis via reshaping gut microbiota and short-chain fatty acid production.

BACKGROUND: Ulcerative colitis is a gastrointestinal disease closely related to intestinal epithelial barrier damage and intestinal microbiome imbalance; however, effective treatment methods are currently limited. Rehmannia glutinosa polysaccharide (RGP) is an important active ingredient with a wide range of pharmacological activities, although its protective effect on colitis remains to be explored. In the present study, we verified the in vitro anti-inflammatory effect of RGP, and observed the ameliorating effect of RGP on dextran sulfate sodium-induced colitis in mice. RESULTS: The results showed that (i) RGP attenuates lipopolysaccharide-induced overexpression of inflammatory factors in RAW264.7 cells; (ii) RGP improves the pathological damage caused by DSS, including weight loss, increased disease activity index and intestinal tissue ulcers; (iii) RGP improves tight junction proteins to protects the tightness of the intestinal epithelium; (iv) RGP inhibits the expression of inflammatory factors through the nuclear factor-kappa B pathway, and improved the of intestinal tissues inflammation; and (v) RGP can maintain the species diversity of intestinal microbes, increase the content of short-chain fatty acids and then restore the imbalance of intestinal microecology. CONCLUSION: RGP can improve the intestinal microbiota to strengthen the intestinal epithelial barrier and protect against DSS-induced colitis. © 2022 Society of Chemical Industry.

Glucosylceramide Changes Bacterial Metabolism and Increases Gram-Positive Bacteria through Tolerance to Secondary Bile Acids In Vitro.

Glucosylceramide is present in many foods, such as crops and fermented foods. Most glucosylceramides are not degraded or absorbed in the small intestine and pass through the large intestine. Glucosylceramide exerts versatile effects on colon tumorigenesis, skin moisture, cholesterol metabolism and improvement of intestinal microbes in vivo. However, the mechanism of action has not yet been fully elucidated. To gain insight into the effect of glucosylceramide on intestinal microbes, glucosylceramide was anaerobically incubated with the dominant intestinal microbe, Blautia coccoides, and model intestinal microbes. The metabolites of the cultured broth supplemented with glucosylceramide were significantly different from those of broth not treated with glucosylceramide. The number of Gram-positive bacteria was significantly increased upon the addition of glucosylceramide compared to that in the control. Glucosylceramide endows intestinal microbes with tolerance to secondary bile acid. These results first demonstrated that glucosylceramide plays a role in the modification of intestinal microbes.

Role of Intestinal Microbes in Chronic Liver Diseases.

With the recent availability and upgrading of many emerging intestinal microbes sequencing technologies, our research on intestinal microbes is changing rapidly. A variety of investigations have found that intestinal microbes are essential for immune system regulation and energy metabolism homeostasis, which impacts many critical organs. The liver is the first organ to be traversed by the intestinal portal vein, and there is a strong bidirectional link between the liver and intestine. Many intestinal factors, such as intestinal microbes, bacterial composition, and intestinal bacterial metabolites, are deeply involved in liver homeostasis. Intestinal microbial dysbiosis and increased intestinal permeability are associated with the pathogenesis of many chronic liver diseases, such as alcoholic fatty liver disease (AFLD), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), chronic hepatitis B (CHB), chronic hepatitis C (CHC), autoimmune liver disease (AIH) and the development of hepatocellular carcinoma (HCC). Intestinal permeability and dysbacteriosis often lead to Lipopolysaccharide (LPS) and metabolites entering in serum. Then, Toll-like receptors activation in the liver induces the exposure of the intestine and liver to many small molecules with pro-inflammatory properties. And all of these eventually result in various liver diseases. In this paper, we have discussed the current evidence on the role of various intestinal microbes in different chronic liver diseases. As well as potential new therapeutic approaches are proposed in this review, such as antibiotics, probiotics, and prebiotics, which may have an improvement in liver diseases.

Functional differentiation related to decomposing complex carbohydrates of intestinal microbes between two wild zokor species based on 16SrRNA sequences.

BACKGROUND: The intestinal microbes in mammals play a key role in host metabolism and adaptation. As a subterranean rodent, zokor digs tunnels for foraging and mating. These digging activities of zokors increase the energy expenditure relative to their aboveground counterparts. However, relatively little is known regarding intestinal microbes of zokor and how they make full use of limited food resources underground for high energy requirements. RESULTS: Eospalax cansus and Eospalax rothschildi had distinct intestinal microbes. Although the composition of intestinal microbes is similar in two species, the proportion of bacterium are distinctly different between them. At phylum level, 11 phyla were shared between two species. Firmicutes and Bacteroidota were two dominant microbes in both of two species, while Eospalax cansus have a significantly high proportion of Firmicutes/Bacteroidota than that of Eospalax rothschildi. At genus level, norank_f_Muribaculaceae were dominant microbes in both of two zokor species. The relative abundance of 12 genera were significantly different between two species. Some bacterium including unclassified_f__Lachnospiraceae, Lachnospiraceae_NK4A136_group, Ruminococcus and Eubacterium_siraeum_group associated with cellulose degradation were significantly enriched in Eospalax cansus. Although alpha diversity was with no significant differences between Eospalax cansus and Eospalax rothschildi, the intestinal microbes between them are significant distinct in PCoA analysis. We have found that trapping location affected the alpha diversity values, while sex and body measurements had no effect on alpha diversity values. PICRUSt metagenome predictions revealed significant enrichment of microbial genes involved in carbohydrate metabolism in Eospalax cansus rather than Eospalax rothschildi. CONCLUSIONS: Our results demonstrate that Eospalax cansus harbor a stronger ability of fermentation for dietary plants than Eospalax rothschildi. The stronger ability of fermentation and degradation of cellulose of intestinal microbes of Eospalax cansus may be a long-time adaptation to limited food resources underground.

A Metagenomic Study of Intestinal Microbial Diversity in Relation to Feeding Habits of Surface and Cave-Dwelling Sinocyclocheilus Species.

Light is completely absent in cave habitats, causing a shortage or lack of autochthonous photosynthesis. Thus, understanding the mechanisms underlying the ability of organisms to adapt to the unique cave habitat is of great interest. We used high-throughput sequencing of the 16S ribosomal RNA gene of intestinal microorganisms from 11 Sinocyclocheilus (Cypriniformes: Cyprinidae) species, to explore the characteristics of intestinal microorganisms and the adaptive mechanisms of Sinocyclocheilus cavefish and surface fish. We found that the α-diversity and richness of the intestinal microbiome were much higher in cavefish than in surface fish. Principal coordinate analysis showed that cavefish and surface fish formed three clusters because of different dominant gut microorganisms which are generated by different habitats. Based on PICRUSt-predicted functions, harmful substance degradation pathways were much more common in cavefish intestinal microorganisms than in those from surface fish. The intestinal microbiota of surface fish group 1 had a higher capacity for carbohydrate metabolism, whereas protein and amino acid metabolism and digestive pathways were more abundant in microorganisms from the cavefish group and surface fish group 2. Combined analysis of the intestinal microbial composition and functional predictions further revealed the structures and functions of intestinal microbial communities in Sinocyclocheilus cave and surface species. Moreover, based on their habits and intestinal microbial composition and intestinal microbial functional predictions, we inferred that the three fish groups were all omnivorous; however, surface fish group 1 preferred feeding on plants, while surface fish group 2 and cavefish preferred meat. This study improves our understanding of mechanisms of adaptation in cave habitats and may contribute to the protection of these habitats from water pollution.

Considerations for the design and conduct of human gut microbiota intervention studies relating to foods.

With the growing appreciation for the influence of the intestinal microbiota on human health, there is increasing motivation to design and refine interventions to promote favorable shifts in the microbiota and their interactions with the host. Technological advances have improved our understanding and ability to measure this indigenous population and the impact of such interventions. However, the rapid growth and evolution of the field, as well as the diversity of methods used, parameters measured and populations studied, make it difficult to interpret the significance of the findings and translate their outcomes to the wider population. This can prevent comparisons across studies and hinder the drawing of appropriate conclusions. This review outlines considerations to facilitate the design, implementation and interpretation of human gut microbiota intervention studies relating to foods based upon our current understanding of the intestinal microbiota, its functionality and interactions with the human host. This includes parameters associated with study design, eligibility criteria, statistical considerations, characterization of products and the measurement of compliance. Methodologies and markers to assess compositional and functional changes in the microbiota, following interventions are discussed in addition to approaches to assess changes in microbiota-host interactions and host responses. Last, EU legislative aspects in relation to foods and health claims are presented. While it is appreciated that the field of gastrointestinal microbiology is rapidly evolving, such guidance will assist in the design and interpretation of human gut microbiota interventional studies relating to foods.

A new recombinant MS-superoxide dismutase alleviates 5-fluorouracil-induced intestinal mucositis in mice.

Intestinal mucositis is a common side effect of anticancer regimens that exerts a negative impact on chemotherapy. Superoxide dismutase (SOD) is a potential therapy for mucositis but efficient product is not available because the enzyme is degraded following oral administration or induces an immune reaction after intravascular infusion. Multi-modified Stable Anti-Oxidant Enzymes® (MS-AOE®) is a new recombinant SOD with better resistance to pepsin and trypsin. We referred it as MS-SOD to distinguish from other SODs. In this study we investigated its potential to alleviate 5-FU-induced intestinal injury and the mechanisms. An intestinal mucositis model was established in C57/BL6 mice by 5-day administration of 5-FU (50 mg/kg every day, ip). MS-SOD (800 IU/10 g, ig) was given once daily for 9 days. 5-FU caused severe mucositis with intestinal morphological damage, bodyweight loss and diarrhea; MS-SOD significantly decreased the severity. 5-FU markedly increased reactive oxygen species (ROS) and inflammatory cytokines in the intestine which were ameliorated by MS-SOD. Furthermore, MS-SOD modified intestinal microbes, particularly reduced Verrucomicrobia, compared with the 5-FU group. In Caco2 cells, MS-SOD (250-1000 U/mL) dose-dependently decreased tBHP-induced ROS generation. In RAW264.7 cells, MS-SOD (500 U/mL) had no effect on LPS-induced inflammatory cytokines, but inhibited iNOS expression. These results demonstrate that MS-SOD can scavenge ROS at the initial stage of injury, thus play an indirect role in anti-inflammatory and barrier protein protection. In conclusion, MS-SOD attenuates 5-FU-induced intestinal mucositis by suppressing oxidative stress and inflammation, and influencing microbes. MS-SOD may exert beneficial effect in prevention of intestinal mucositis during chemotherapy in clinic.

Intestinal Methylation and Demethylation of Mercury.

Mercury (Hg) is a global pollutant, which is linked with different diseases. The methylation of Hg and demethylation of methylmercury (MeHg) in the environment were extensively studied and summarized; however, the transformation of Hg in the intestine is less presented. In this review, the research progress and the perspectives on the intestinal transformation of Hg were discussed. Studies found that MeHg could be formed when exposed to inorganic Hg by the gut microbiota in aquatic organisms, terrestrial invertebrates, and mammals, etc. hgcAB genes could be used as indicators for predicting Hg methylation potential. In vitro studies using fecal specimen, intestinal contents, and the isolated intestinal microbes confirmed the intestinal demethylation of MeHg. The investigation on the effects of Hg exposure to the abundance and diversity of intestinal microbes and their metabolites could shed light on the mechanism of the toxicity of Hg, especially the neurotoxicity of MeHg, which deserves further study.

[Research progress of interaction models between intestinal microflora and host cells].

Intestinal microbes play an important role in human health. The development of various clinical diseases, such as obesity, diabetes and cardiovascular disease, is closely related to the imbalance of intestinal microflora. With the development of high-throughput sequencing technology, there has been a breakthrough in the understanding of intestinal microorganism. The interaction between intestinal epithelial cells and intestinal microbes has become one of the hotspots and difficulties of current research. Because of the constraints of ethical review and experimental cost, people are more interested in the development of interaction models between the intestinal microflora and the host cells. In this paper, interaction models between intestinal microflora and host cells, and its working principle and application prospect are reviewed, hoping to provide new techniques and new ideas for studying functions of intestinal microbes.