Correlation between the regulation of intestinal bacteriophages by green tea polyphenols and the flora diversity in SPF mice.

Green tea polyphenols (GTP) play an important role in shaping the gut microbiome, comprising a range of densely colonizing microorganisms, including bacteriophages. Previous studies focused on the effect of GTP on the bacteria in the gut microbiota. However, little is known about the role of GTP in the bacteriophage composition of healthy intestines. In this study, SPF male C57BL/6J mice were divided into a polyphenol-free diet group and a tea polyphenol diet group where drinking water was supplemented with 0.1% GTP for 28 days. The ultra-deep metagenomic sequencing of virus-like particle preparations and bacterial 16S rRNA sequencing were performed on mouse stool samples. Changes in the gut bacteriome, bacteriophages, and bacterial-bacteriophage correlations were then compared between the groups. The results revealed an abundance of Firmicutes, a significant decrease in Bacteroidetes, and a significant increase in the ratio of F/B after GTP exposure. The GTP altered the abundance (relative abundance > 1.00%) of Bifidobacterium (regulation rate of 89.78% and the abundance up-regulated by 0.89%) and Akkermansia (regulation rate of 99.70% and the abundance down-regulated by 1.77%). The abundance of Faecalibaculum (regulation rate of 60.17%) increased by 24.38% following GTP treatment. The GTP also altered the abundance of Salmonella phage (regulation rate of 98.64% and the abundance up-regulated by 3.16%) and that of Gordonia_phage_Yakult (regulation rate of 99.99% and the abundance down-regulated by 5.44%). It significantly increased the intestine's lytic phages and reduced the temperate phages by 29.22%. The dominant microorganisms (relative abundance >1.00%) of Bifidobacterium and Dubosiella had a significantly negative relationship with the Faecalibacterium phage and a significantly positive relationship with the Lactobacillus prophage. Exposure to GTP positively promoted changes in the gut bacteriophage community and interaction network in the microbial community of the SPF mice. These findings highlight the importance of "profitable" bacteriophage-bacteria relationships and reveal a potential mechanism of GTP towards the regulation of intestinal flora via intestinal phage communities.

Norepinephrine depleting toxin DSP-4 and LPS alter gut microbiota and induce neurotoxicity in α-synuclein mutant mice.

This study examined the genetic mutation and toxicant exposure in producing gut microbiota alteration and neurotoxicity. Homozygous α-synuclein mutant (SNCA) mice that overexpress human A53T protein and littermate wild-type mice received a single injection of LPS (2 mg/kg) or a selective norepinephrine depleting toxin DSP-4 (50 mg/kg), then the motor activity, dopaminergic neuron loss, colon gene expression and gut microbiome were examined 13 months later. LPS and DSP-4 decreased rotarod and wirehang activity, reduced dopaminergic neurons in substantia nigra pars compacta (SNpc), and SNCA mice were more vulnerable. SNCA mice had 1,000-fold higher human SNCA mRNA expression in the gut, and twofold higher gut expression of NADPH oxidase (NOX2) and translocator protein (TSPO). LPS further increased expression of TSPO and IL-6 in SNCA mice. Both LPS and DSP-4 caused microbiome alterations, and SNCA mice were more susceptible. The altered colon microbiome approximated clinical findings in PD patients, characterized by increased abundance of Verrucomicrobiaceae, and decreased abundance of Prevotellaceae, as evidenced by qPCR with 16S rRNA primers. The Firmicutes/Bacteroidetes ratio was increased by LPS in SNCA mice. This study demonstrated a critical role of α-synuclein and toxins interactions in producing gut microbiota disruption, aberrant gut pro-inflammatory gene expression, and dopaminergic neuron loss.

Molecular mechanisms of polysaccharides from Ziziphus jujuba Mill var. spinosa seeds regulating the bioavailability of spinosin and preventing colitis.

In this study, the effect of Ziziphus jujuba Mill var. spinosa seeds (ZSS) polysaccharides on the bioavailability of spinosin in mice and its molecular mechanism were investigated. After continuously fed with ZSS polysaccharides 100 mg/kg·d-1 for 28 consecutive days, the C57BL/6 mice absorbed spinosin at an obvious lower level compared with the control group. The expression levels of P-gp, MRP2 and Occludin in the colon were significantly increased. ZSS polysaccharides significantly regulated the composition of the gut microbiota, reducing the abundance of Bacteroidetes, and increasing the richness of Firmicutes and Verrucomicrobia. Moreover, ZSS polysaccharides can significantly regulate the expression levels of tight junction proteins and efflux transporters in Caco-2 cells. However, the gut microbiota culture supernatant showed no obvious biological activity in this regard. Furthermore, histopathological analysis revealed ZSS polysaccharides can alleviate TNBS-induced colitis, reduced inflammatory cell infiltration in mice. This immune regulation was related to the NF-κB and MAPK pathways in RAW264.7 cells.

Sanguinarine modulate gut microbiome and intestinal morphology to enhance growth performance in broilers.

Sanguinarine is a bioactive compound as a quaternary benzophenanthridine alkaloid from plant of the Macleaya cordata, Papaveraceae family. The present study was conducted to investigate the effects of dietary sanguinarine supplementation on growth performance, serum biochemistry parameters, intestinal mucosal morphology and gut microbiome in yellow feathered broilers. Two hundred and seventy 1-d-old female broilers were randomly assigned to 3 treatments ① Basal diet (NG); ② Basal diet containing bacitracin methylene disalicylate (50mg/Kg diet) (ANT); ③ Basal diet containing sanguinarine (0.7 mg/ kg of feed) (SAG). The statistical results showed that dietary sanguinarine supplementation enhanced growth performance and decreased glucose, uric acid as well as urea nitrogen levels of broilers at 28d of age (P<0.05). The 16S rRNA gene sequence analysis revealed that sanguinarine significantly decreased the species from the phyla Bacteroidetes, and increased the species from phyla Firmicutes. Moreover, dietary sanguinarine supplementation improved mucosal morphology to achieve higher ratio of intestinal villus height to crypt depth (P < 0.05), and decreased the concentrations of TNF-α and IL-4 in jejunum mucosal. This study demonstrated that sanguinarine supplementation in the diet of yellow feathered broilers improved intestinal morphology and microbiota community structure to promote growth performance on 1-28d.

Effects of fucoidan on gut flora and tumor prevention in 1,2-dimethylhydrazine-induced colorectal carcinogenesis.

Colorectal cancer (CRC) is one of the major malignancies in humans. This study was designed to evaluate the effects of fucoidan on gut flora and tumor prevention in 1,2-dimethylhydrazine-induced colorectal carcinogenesis in rats. We found that dietary fucoidan treatment decreased the tumor incidence and mean tumor weight and increased cell apoptosis. Fucoidan treatment decreased the expression of ß-catenin C-Myc, CyclinD1 and Survivin, while the Hippo pathway was activated with increased phosphorylation levels of mammalian sterile 20-like kinase 1 and 2, large tumor suppressor 1 and 2, and Yes-associated protein. Compared with the model group, the levels of interleukin (IL)-17 and IL-23 were decreased, but the levels of interferon-γ, IL-4 and IL-10 were increased, in the fucoidan group. Fucoidan treatment increased natural killer cells in peripheral blood and the proportion of CD4+ T cells. Immunofluorescence detection of colorectal tumor tissues showed decreased expression of Foxp3 and up-regulated expression of CD68 in the fucoidan group. Moreover, fucoidan treatment decreased the levels of diamine oxidase and lipopolysaccharides and up-regulated the levels of tight junction proteins. 16S rDNA high-throughput sequencing revealed that fucoidan treatment decreased the abundance of Prevotella and increased the abundance of Alloprevotella. Fucoidan increased the levels of butyric acid and valeric acid compared to the model group. This study provides experimental evidence that dietary fucoidan may prevent colorectal tumorigenesis by regulating gut microecology and body immunity. Meanwhile, fucoidan activated the Hippo pathway and down-regulated the ß-catenin pathway to induce tumor cell apoptosis and suppress tumor growth.

Amino Acids Regulate Glycolipid Metabolism and Alter Intestinal Microbial Composition.

Amino acids (AAs) and their metabolites regulate key metabolic pathways that are necessary for growth, reproduction, immunity and metabolism of the body. It has been convinced that metabolic diseases are closely related to disorders of glycolipid metabolism. A growing number of studies have shown that AAs are closely related to energy metabolism. This review focuses on the effects of amino acids (arginine, branched-chain amino acids, glutamine) and their metabolites (short chain fatty acids) on glycolipid metabolism by regulating PI3K/AKT/mTOR and AMPK signaling pathways and GPCRs receptors, reducing intestinal Firmicutes/Bacteroidetes ratio associated with obesity.

Preparation and preliminary evaluation of bio-nanocomposites based on hydroxyapatites with antibacterial properties against anaerobic bacteria.

Hexagonal nanocrystalline powders of the non-doped Ca10(PO4)6(OH)2 as well as activated with Ag+ and Eu3+ ions were synthesized by using different wet chemistry methods. Moreover, the obtained hydroxyapatite was loaded with Ag0, as well as nitroimidazole antimicrobials: metronidazole and tinidazole. The structural properties of the products were analyzed by X-ray diffraction (XRD), scanning (SEM) and transmission (TEM) electron microscopy as well as infrared (IR) and Raman spectroscopy. The photoluminescence properties of the Eu3+ and Ag+ co-doped Ca10(PO4)6(OH)2 were characterized via the PL emission, excitation spectra and the luminescence decay curve. The antimicrobial activity of the obtained materials against Prevotella bivia and Parabacteroides distasonis was studied. The cytotoxicity assessment was carried out on the human osteosarcoma cell line (U2OS) as well as human red blood cells (RBC). The choice of the in vitro model was based on the fact that U2OS is a cancer cell line derived from bone tissue which is rich in apatites that play a pivotal role in the extracellular matrix formation. RBCs are the most abundant blood cells and they are used as a cell model in the study of biocompatibility of new prepared biocompounds with potential medical applications. The obtained multifunctional materials do not exhibit the haemolytic activity, therefore, they could be used as a promising antimicrobial agent and for anaerobic bacteria.

Chitin-glucan and pomegranate polyphenols improve endothelial dysfunction.

The vascular dysfunction is the primary event in the occurrence of cardio-vascular risk, and no treatment exists until now. We tested for the first time the hypothesis that chitin-glucan (CG) - an insoluble fibre with prebiotic properties- and polyphenol-rich pomegranate peel extract (PPE) can improve endothelial and inflammatory disorders in a mouse model of cardiovascular disease (CVD), namely by modulating the gut microbiota. Male Apolipoprotein E knock-out (ApoE-/-) mice fed a high fat (HF) diet developed a significant endothelial dysfunction attested by atherosclerotic plaques and increasing abundance of caveolin-1 in aorta. The supplementation with CG + PPE in the HF diet reduced inflammatory markers both in the liver and in the visceral adipose tissue together with a reduction of hepatic triglycerides. In addition, it increased the activating form of endothelial NO-synthase in mesenteric arteries and the heme-nitrosylated haemoglobin (Hb-NO) blood levels as compared with HF fed ApoE-/- mice, suggesting a higher capacity of mesenteric arteries to produce nitric oxide (NO). This study allows to pinpoint gut bacteria, namely Lactobacillus and Alistipes, that could be implicated in the management of endothelial and inflammatory dysfunctions associated with CVD, and to unravel the role of nutrition in the modulation of those bacteria.

Neohesperidin prevents colorectal tumorigenesis by altering the gut microbiota.

Neohesperidin (NHP), derived from citrus fruits, has attracted considerable interest due to its preventative and therapeutic effects on numerous diseases. However, little progress has been made in determining the exact function of NHP on tumorigenesis. In the current study, we found that NHP inhibited colorectal tumorigenesis in the APC min/+ transgenic mouse model, as well as induced apoptosis and blocked angiogenesis in vivo. Our in-cell study suggested that this tumorigenic preventative effect of NHP is not due to the direct impact on tumor cells. Intriguingly, by utilizing 16 s rRNA gene-based microbiota sequencing, the relative abundance of Bacteroidetes was decreased, while Firmicutes and Proteobacteria were increased in the presence of NHP. Additionally, the fecal microbiota transplantation experiment further revealed that feeding with fecal of NHP-treated mice induced considerable inhibition of tumorigenesis, which indicates that the alteration of gut microbiota is responsible for NHP-mediated prevention of colorectal tumorigenesis. Thus, our study not only suggests the efficacy of NHP as a potent natural product for preventing colorectal cancer but also proposes a compelling model to connect the gut microbiota to the preventative effect of NHP on tumorigenesis.

A family of anti-Bacteroidales peptide toxins wide-spread in the human gut microbiota.

Bacteria often produce antimicrobial toxins to compete in microbial communities. Here we identify a family of broad-spectrum peptide toxins, named bacteroidetocins, produced by Bacteroidetes species. We study this toxin family using phenotypic, mutational, bioinformatic, and human metagenomic analyses. Bacteroidetocins are related to class IIa bacteriocins of Gram-positive bacteria and kill members of the Bacteroidetes phylum, including Bacteroides, Parabacteroides, and Prevotella gut species, as well as pathogenic Prevotella species. The bacteroidetocin biosynthesis genes are found in horizontally acquired mobile elements, which likely allow dissemination within the gut microbiota and may explain their wide distribution in human populations. Bacteroidetocins may have potential applications in microbiome engineering and as therapeutics for polymicrobial diseases such as bacterial vaginosis and periodontal disease.

Gut bacteria of the cowpea beetle mediate its resistance to dichlorvos and susceptibility to Lippia adoensis essential oil.

Bacteria inhabiting the gut of insects provide many benefits to their hosts, such as aiding in food digestion, reproduction, and immunity, tissue homeostasis, adaptation to environment and resistance to pathogen and pesticides. The cowpea beetle, Callosobruchus maculatus, is a serious cosmopolitan pest of pulses. This beetle has lent itself as a guinea pig for several ecological studies. It harbors a consortium of bacterial communities in its gut, but the evidence for their role in its physiology is fragmentary. In this work, we hypothesized that gut microbiota mediates C. maculatus resistance to dichlorvos (DDVP or O,O-dimethyl O-2,2-dichlorovinylphosphate) and represent the target of Lippia adoensis (Gambian Tea Bush) essential oil (EO). Symbiotic and aposymbiotic beetles were exposed to artificial cowpea seeds earlier treated with DDVP or EO. Adult mortality and changes in gut bacterial community composition and abundance were examined at F1 and F5 generations. The susceptibility of experimental beetles to DDVP was significantly affected by their symbiotic status. The adult mortality decreased across generations in DDVP treatments, and remained significantly higher in aposymbiotic groups. In EO treatments, the mortality was consistent irrespective of symbiotic status and experimental generations. When compared to DDVP and the Control, EO treatments had significantly lower bacterial richness and diversity, as well as lower abundance of Proteobacteria, Firmicutes, and Bacteroidetes. These results support our hypothesis and describe the responses of gut microbial communities to pesticide treatments. This could be of interest for developing new management strategies of this pest.

The pandanus tectorius fruit extract (PTF) modulates the gut microbiota and exerts anti-hyperlipidaemic effects.

BACKGROUND: The gut microbiota plays a key role in the maintenance of human health and mediates the beneficial effects of natural products including polyphenols. Previous studies have demonstrated that the polyphenol-rich Pandanus tectorius fruit extract (PTF) was effective in ameliorating high-fat diet (HFD)-induced hyperlipidaemia, and polyphenols can significantly change the structure of the gut microbiota. PURPOSE: In this study, we assessed whether the modulation of the gut microbiota plays a key role in the PTF-induced anti-hyperlipidaemic effects. METHODS: Male C57BL/6 J mice were induced with hyperlipidaemia by consuming a high-fat diet (HFD) for 4 weeks. Then, the mice were orally administered PTF, antibiotics (ampicillin+ norfloxacin), PTF+antibiotics or vehicle for another 6 weeks. Body weights and 24-h food intake were assessed weekly. At the end of the experiment, fresh stools were collected for 16S RNA pyrosequencing, and blood and liver and fat tissue were collected for pharmacological analysis. RESULTS: PTF was effective in ameliorating high-fat diet (HFD)-induced hyperlipidaemia and significantly changed the structure of the gut microbiota. However, the anti-hyperlipidaemic effect of PTF was not influenced by the co-treatment with antibiotics (ampicillin+norfloxacin). A microbiological analysis of the gut microbiotas revealed that PTF selectively enhanced the relative abundance of Lactobacillus and decreased the relative abundance of Bacteroides and Alistipes. A correlation analysis between biochemical indexes and individual taxon showed that Lactobacillus was negatively associated with serum lipids and glucose while Bacteroides and Alistipes were positively associated with serum lipids and glucose. The modulatory effect of PTF on Lactobacillus, Bacteroides and Alistipes was not disturbed by the administration of antibiotics. CONCLUSION: These results demonstrated that the polyphenol-rich PTF as a unique gut microbiota modulating agent and highlighted the richness of Lactobacillus and the decreased abundance of Bacteroides and Alistipes as an effective indicator of the therapeutic effect of medicinal foods on hyperlipidaemia.

Oat bran, but not its isolated bioactive ß-glucans or polyphenols, have a bifidogenic effect in an in vitro fermentation model of the gut microbiota.

Wholegrain oats are known to modulate the human gut microbiota and have prebiotic properties (increase the growth of some health-promoting bacterial genera within the colon). Research to date mainly attributes these effects to the fibre content; however, oat is also a rich dietary source of polyphenols, which may contribute to the positive modulation of gut microbiota. In vitro anaerobic batch-culture experiments were performed over 24 h to evaluate the impact of two different doses (1 and 3 % (w/v)) of oat bran, matched concentrations of ß-glucan extract or polyphenol mix, on the human faecal microbiota composition using 16S RNA gene sequencing and SCFA analysis. Supplementation with oats increased the abundance of Proteobacteria (P <0·01) at 10 h, Bacteroidetes (P <0·05) at 24 h and concentrations of acetic and propionic acid increased at 10 and 24 h compared with the NC. Fermentation of the 1 % (w/v) oat bran resulted in significant increase in SCFA production at 24 h (86 (sd 27) v. 28 (sd 5) mm; P <0·05) and a bifidogenic effect, increasing the relative abundance of Bifidobacterium unassigned at 10 h and Bifidobacterium adolescentis (P <0·05) at 10 and 24 h compared with NC. Considering the ß-glucan treatment induced an increase in the phylum Bacteroidetes at 24 h, it explains the Bacteriodetes effects of oats as a food matrix. The polyphenol mix induced an increase in Enterobacteriaceae family at 24 h. In conclusion, in this study, we found that oats increased bifidobacteria, acetic acid and propionic acid, and this is mediated by the synergy of all oat compounds within the complex food matrix, rather than its main bioactive ß-glucan or polyphenols. Thus, oats as a whole food led to the greatest impact on the microbiota.

Bacterial community changes in response to oil contamination and perennial crop cultivation.

We investigated bacterial community dynamics in response to used motor oil contamination and perennial crop cultivation by 16S rRNA gene amplicon sequencing in a 4-year field study. Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, and Gemmatimonadetes were the major bacterial phyla, and Rhodococcus was the most abundant genus. Initially, oil contamination decreased the overall bacterial diversity. Actinobacteria, Betaproteobacteria, and Gammaproteobacteria were sensitive to oil contamination, exhibiting clear succession with time. However, bacterial communities changed over time, regardless of oil contamination and crop cultivation. The abundance difference of most OTUs between oil-contaminated and non-contaminated plots remained the same in later sampling years after the initial abundance difference induced by oil spike. The abundances of three oil-favored actinobacteria (Lysinimonas, Microbacteriaceae, and Marmoricola) and one betaproteobacterium (Aquabacterium) changed in different manner over time in oil-contaminated and non-contaminated soil. We propose that these taxa are potential bio-indicators for monitoring recovery from motor oil contamination in boreal soil. The effect of crop cultivation on bacterial communities became significant only after the crops achieved stable growth, likely associated with plant material decomposition by Bacteroidetes, Armatimonadetes and Fibrobacteres.

The Artificial Sweetener Splenda Promotes Gut Proteobacteria, Dysbiosis, and Myeloperoxidase Reactivity in Crohn's Disease-Like Ileitis.

Background: Epidemiological studies indicate that the use of artificial sweeteners doubles the risk for Crohn's disease (CD). Herein, we experimentally quantified the impact of 6-week supplementation with a commercial sweetener (Splenda; ingredients sucralose maltodextrin, 1:99, w/w) on both the severity of CD-like ileitis and the intestinal microbiome alterations using SAMP1/YitFc (SAMP) mice. Methods: Metagenomic shotgun DNA sequencing was first used to characterize the microbiome of ileitis-prone SAMP mice. Then, 16S rRNA microbiome sequencing, quantitative polymerase chain reaction, fluorescent in situ hybridization (FISH), bacterial culture, stereomicroscopy, histology, and myeloperoxidase (MPO) activity analyses were then implemented to compare the microbiome and ileitis phenotype in SAMP with that of control ileitis-free AKR/J mice after Splenda supplementation. Results: Metagenomics indicated that SAMP mice have a gut microbial phenotype rich in Bacteroidetes, and experiments showed that Helicobacteraceae did not have an exacerbating effect on ileitis. Splenda did not increase the severity of (stereomicroscopic/histological) ileitis; however, biochemically, ileal MPO activity was increased in SAMP treated with Splenda compared with nonsupplemented mice (P < 0.022) and healthy AKR mice. Splenda promoted dysbiosis with expansion of Proteobacteria in all mice, and E. coli overgrowth with increased bacterial infiltration into the ileal lamina propria of SAMP mice. FISH showed increase malX gene-carrying bacterial clusters in the ilea of supplemented SAMP (but not AKR) mice. Conclusions: Splenda promoted gut Proteobacteria, dysbiosis, and biochemical MPO reactivity in a spontaneous model of (Bacteroidetes-rich) ileal CD. Our results indicate that although Splenda may promote parallel microbiome alterations in CD-prone and healthy hosts, this did not result in elevated MPO levels in healthy mice, only CD-prone mice. The consumption of sucralose/maltodextrin-containing foods might exacerbate MPO intestinal reactivity only in individuals with a pro-inflammatory predisposition, such as CD.

Proanthocyanidin-Rich Grape Seed Extract Modulates Intestinal Microbiota in Ovariectomized Mice.

Grape-seed extract (GSE) is rich in proanthocyanidins (polymers of flavan-3-ols). GSE is well known to have various beneficial effects to health. The objective of this study was to examine the effect of dietary GSE on the intestinal microbiota in ovariectomized (OVX) mice as a model of menopause. Phylum-level analyses using 16S rRNA-targeted group-specific polymerase-chain reaction primers in fecal samples collected 8 weeks postoperatively from OVX mice revealed that the proportion of Firmicutes and Bacteroidetes populations became imbalanced as compared with that in sham-operated control mice. That is, the ratio of Firmicutes:Bacteroidetes populations in the OVX group were increased significantly. When OVX animals were given dietary GSE, the imbalanced proportion of Firmicutes and Bacteroidetes populations was normalized to that seen in control mice. In addition, the body weight of OVX animals measured at 6 weeks postoperatively was significantly higher than that in sham-operated control animals. Dietary GSE also prevented OVX animals from increasing body weight. Thus, we postulated that GSE can improve imbalanced populations of intestinal microbiota, leading to prevention of obesity under conditions of not only menopause but morbidity. PRACTICAL APPLICATION: The GSE has a great potential to be a functional food to improve dysbiosis in post-menopausal women.

Isoliquiritigenin decreases the incidence of colitis-associated colorectal cancer by modulating the intestinal microbiota.

Imbalances in intestinal bacteria correlate with colitis-associated colorectal cancer (CAC). Traditional Chinese medicines have been used to adjust the gut microbiota, and isoliquiritigenin (ISL), a flavonoid extracted from licorice, has shown antitumor efficacy. In this study, the effects of ISL on CAC development and the gut microbiota were evaluated using an azoxymethane and dextran sulphate sodium (AOM/DSS)-induced mouse model of CAC (CACM). Histopathological analysis suggested that ISL reduced tumor incidence in vivo. Moreover, high-throughput sequencing and terminal restriction fragment length polymorphism (T-RFLP) studies of the bacterial 16S rRNA gene revealed that the structure of the gut microbial community shifted significantly following AOM/DSS treatment, and that effect was alleviated by treatment with high-dose ISL (150 mg/kg). Compared to the microbiota in the control mice (CK), the levels of Bacteroidetes decreased and the levels of Firmicutes increased during CAC development. ISL reversed the imbalance at the phylum level and altered the familial constituents of the gut microbiota. Specifically, the abundance of Helicobacteraceae increased after treatment with high-dose ISL, while the abundance of Lachnospiraceae and Rikenellaceae decreased. At the genus level, ISL reduced the abundance of opportunistic pathogens (Escherichia and Enterococcus), and increased the levels of probiotics, particularly butyrate-producing bacteria (Butyricicoccus, Clostridium, and Ruminococcus). Thus, ISL protects mice from AOM/DSS-induced CAC, and ISL and the gut microbiota may have synergistic anti-cancer effects.

Influence of Endogenous and Exogenous Estrogenic Endocrine on Intestinal Microbiota in Zebrafish.

Gender is one of the factors influencing the intestinal microbial composition in mammals, but whether fish also have gender-specific intestinal microbial patterns remains unknown. In this decade, endocrine disrupting chemicals in surface and ground water of many areas and increasing observation of freshwater male fish displaying female sexual characteristics have been reported. Here we identified the difference in intestinal microbiota between male and female zebrafish, and revealed the influence of endocrine disrupting chemicals on zebrafish intestinal microbiota by using high-throughput sequencing. The results indicated that Fusobacteria, Bacteroidetes and Proteobacteria were dominant in the gut of zebrafish and there were no obvious gender-specific intestinal microbial patterns. Two endocrine disrupting chemicals, Estradiol (E2) and Bisphenol A (BPA), were selected to treat male zebrafish for 5 weeks. E2 and BPA increased vitellogenin expression in the liver of male zebrafish and altered the intestinal microbial composition with the abundance of the phylum CKC4 increased significantly. Our results suggested that because of the developmental character and living environment, gender did not influence the assembly of intestinal microbiota in zebrafish as it does in mammals, but exposure extra to endocrine disrupting chemicals disturbed the intestinal microbial composition, which may be related to changes in host physiological metabolism.

Oral imazalil exposure induces gut microbiota dysbiosis and colonic inflammation in mice.

The fungicide imazalil (IMZ) is used extensively in vegetable and fruit plantations and as a post-harvest treatment to avoid rot. Here, we revealed that ingestion of 25, 50 and 100 mg IMZ kg(-1) body weight for 28 d induced gut microbiota dysbiosis and colonic inflammation in mice. The relative abundance of Bacteroidetes, Firmicutes and Actinobacteria in the cecal contents decreased significantly after exposure to 100 mg kg(-1) IMZ for 28 d. In feces, the relative abundance in Bacteroidetes, Firmicutes and Actinobacteria decreased significantly after being exposed to 100 mg kg(-1) IMZ for 1, 14 and 7 d, respectively. High throughput sequencing of the V3-V4 region of the bacterial 16S rRNA gene revealed a significant reduction in the richness and diversity of microbiota in cecal contents and feces of IMZ-treated mice. Operational taxonomic units (OTUs) analysis identified 49.3% of OTUs changed in cecal contents, while 55.6% of OTUs changed in the feces after IMZ exposure. Overall, at the phylum level, the relative abundance of Firmicutes, Proteobacteria and Actinobacteria increased and that of Bacteroidetes decreased in IMZ-treated groups. At the genus level, the abundance of Lactobacillus and Bifidobacterium decreased while those of Deltaproteobacteria and Desulfovibrio increased in response to IMZ exposure. In addition, it was observed that IMZ exposure could induce colonic inflammation characterized by infiltration of inflammatory cells, elevated levels of lipocalin-2 (lcn-2) in the feces, and increased mRNA levels of Tnf-α, IL-1ß, IL-22 and IFN-γ in the colon. Our findings strongly suggest that ingestion of IMZ has some risks to human health.

TCDD modulation of gut microbiome correlated with liver and immune toxicity in streptozotocin (STZ)-induced hyperglycemic mice.

An increasing body of evidence has shown the important role of the gut microbiome in mediating toxicity following environmental contaminant exposure. The goal of this study was to determine if the adverse metabolic effects of chronic 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure would be sufficient to exacerbate hyperglycemia, and to further determine if these outcomes were attributable to the gut microbiota alteration. Adult male CD-1 mice were exposed to TCDD (6µg/kg body weight biweekly) by gavage and injected (i.p.) with STZ (4×50mg/kg body weight) to induced hyperglycemia. 16S rRNA sequencing was used to characterize the changes in the microbiome community composition. Glucose monitoring, flow cytometry, histopathology, and organ characterization were performed to determine the deleterious phenotypic changes of TCDD exposure. Chronic TCDD treatment did not appear to exacerbate STZ-induced hyperglycemia as blood glucose levels were slightly reduced in the TCDD treated mice; however, polydipsia and polyphagia were observed. Importantly, TCDD exposure caused a dramatic change in microbiota structure, as characterized at the phylum level by increasing Firmicutes and decreasing Bacteroidetes while at the family level most notably by increasing Lactobacillaceae and Desulfovibrionaceae, and decreasing Prevotellaceae and ACK M1. The changes in microbiota were further found to be broadly associated with phenotypic changes seen from chronic TCDD treatment. In particular, the phylum level Bacteroidetes to Firmicutes ratio negatively correlated with both liver weight and liver pathology, and positively associated with %CD3(+)NK(+) T cells, a key mediator of host-microbial interactions. Collectively, these findings suggest that the dysregulated gut microbiome may contribute to the deleterious effects (e.g., liver toxicity) seen with TCDD exposure.