Effects of Intestinal Microbiota on the Biological Transformation of Arsenic in Zebrafish: Contribution and Mechanism.

Both the gut microbiome and their host participate in arsenic (As) biotransformation, while their exact roles and mechanisms in vivo remain unclear and unquantified. In this study, as3mt-/- zebrafish were treated with tetracycline (TET, 100 mg/L) and arsenite (iAsIII) exposure for 30 days and treated with probiotic Lactobacillus rhamnosus GG (LGG, 1 × 108 cfu/g) and iAsIII exposure for 15 days, respectively. Structural equation modeling analysis revealed that the contribution rates of the intestinal microbiome to the total arsenic (tAs) and inorganic As (iAs) metabolism approached 44.0 and 18.4%, respectively. Compared with wild-type, in as3mt-/- zebrafish, microbial richness and structure were more significantly correlated with tAs and iAs, and more differential microbes and microbial metabolic pathways significantly correlated with arsenic metabolites (P < 0.05). LGG supplement influenced the microbial communities, significantly up-regulated the expressions of genes related to As biotransformation (gss and gst) in the liver, down-regulated the expressions of oxidative stress genes (sod1, sod2, and cat) in the intestine, and increased arsenobetaine concentration (P < 0.05). Therefore, gut microbiome promotes As transformation and relieves As accumulation, playing more active roles under iAs stress when the host lacks key arsenic detoxification enzymes. LGG can promote As biotransformation and relieve oxidative stress under As exposure.

Two polysaccharides from Rehmannia glutinosa: isolation, structural characterization, and hypoglycemic activities.

Rehmannia glutinosa (RG) as a Chinese herbal medicine can be used both in medicine and food. As the main component of RG, the polysaccharides have a hypoglycemic effect, however, the hypoglycemic activity of RG homopolysaccharides remains unknown. We isolated and purified two polysaccharides, RGP70-1-1 and RGP70-1-2 (4.9 kDa and 2.8 kDa) from RG. The structural characteristics, including monosaccharide composition, linkage, and configuration were analyzed by FT-IR, HPLC, GC-MS, NMR spectroscopy, Congo test, and SEM. RGP70-1-1 and RGP70-1-2 consist of four monosaccharides (glucose, mannose, arabinose, and galactose). RGP70-1-1 contains 14 connection modes, with the linkages including l-Araf-(1→, →3)-l-Araf-(1→, →5)-l-Araf-(1→, →3,5)-l-Araf-(1→, →2,5)-l-Araf-(1→, d-Manp-(1→, →2)-d-Manp-(1→, →4)-d-Manp-(1→, d-Galp-(1→, →4)-d-Galp-(1→, →4,6)-d-Galp-(1→, →6)-d-Glcp-(1→, →4,6)-d-Glcp-(1→, →3,6)-d-Glcp-(1→. The linkages of RGP70-1-2 is including →5)-l-Araf-(1→, →3,5)-l-Araf-(1→, →4)-d-Manp-(1→, →3,6)-d-Manp-(1→, d-Galp-(1→, →6)-d-Galp-(1→, d-Glcp-(1→, →6)-d-Glcp-(1→, →4,6)-d-Glcp-(1→. Furthermore, RGP70-1-1 and RGP70-1-2 can inhibit α-glucosidase and α-amylase. RGP70-1-1 stimulated GLP-1 secretion in STC-1 cells and was related to the up-regulation of PI3K and p-AKT protein expression. The findings revealed a natural product with potential hypoglycemic activity, which may be used as a GLP-1 secretagogue and a beneficial functional food ingredient for T2D.

Long-term effects on liver metabolism induced by ceftriaxone sodium pretreatment.

Ceftriaxone is an emerging contaminant due to its potential harm, while its effects on liver are still need to be clarified. In this study, we first pretreated the 8-week-old C57BL/6J mice with high dose ceftriaxone sodium (Cef, 400 mg/mL, 0.2 mL per dose) for 8 days to prepare a gut dysbiosis model, then treated with normal feed for a two-month recovery period, and applied non-targeted metabolomics (including lipidomics) to investigate the variations of fecal and liver metabolome, and coupled with targeted determination of fecal short-chain fatty acids (SCFAs) and bile acids (BAs). Lastly, the correlations and mediation analysis between the liver metabolism and gut metabolism/microbes were carried, and the potential mechanisms of the mal-effects on gut-liver axis induced by Cef pretreatment were accordingly discussed. Compared to the control group, Cef pretreatment reduced the rate of weight gain and hepatosomatic index, induced bile duct epithelial cells proliferated around the central vein and appearance of binucleated hepatocytes, decreased the ratio of total branching chains amino acids (BCAAs) to total aromatic amino acids (AAAs) in liver metabolome. In fecal metabolome, the total fecal SCFAs and BAs did not change significantly while butyric acid decreased and the primary BAs increased after Cef pretreatment. Correlation and mediation analysis revealed one potential mechanism that Cef may first change the intestinal microbiota (such as destroying its normal structure, reducing its abundance and the stability of the microbial network or certain microbe abundance like Alistipes), and then change the intestinal metabolism (such as acetate, caproate, propionate), leading to liver metabolic disorder (such as spermidine, inosine, cinnamaldehyde). This study proved the possibility of Cef-induced liver damage, displayed the overall metabolic profile of the liver following Cef pretreatment and provided a theoretical framework for further research into the mechanism of Cef-induced liver damage.

The gut microbiome promotes arsenic metabolism and alleviates the metabolic disorder for their mammal host under arsenic exposure.

Gut microbiome can participate in arsenic metabolism. However, its efficacy in the host under arsenic stress is still controversial. To clarify their roles in fecal arsenic excretion, tissue arsenic accumulation, host physiological states and metabolism, in this study, ninety-six C57BL/6 male mice were randomly divided to four groups, groups A and B were given sterile water, and groups C and D were given the third generation of broad-spectrum antibiotic (ceftriaxone) to erase the background gut microbiome. Subsequently, groups B and D were subchronicly exposed to arsenic containing feed prepared by adding arsenical mixture (rice arsenic composition) into control feed. In group D, the fecal total arsenic (CtAs) decreased by 25.5 %, iAsIII composition increased by 46.9 %, unclarified As (uAs) composition decreased by 92.4 %, and the liver CtAs increased by 26.7 %; the fecal CtAs was positively correlated with microbial richness and some metabolites (organic acids, amino acids, carbohydrates, SCFAs, hydrophilic bile acids and their derivatives); and fecal DMA was positively correlated with microbial richness and some metabolites (ferulic acid, benzenepropanoic acid and pentanoic acid); network analysis showed that the numbers of modules, nodes, links were decreased and vulnerability was increased; some SCFAs and hydrophilic bile acid decreased, and hydrophobic bile acids increased (Ps < 0.05). In the tissue samples of group D, Il-18 and Ifn-γ gene expression increased and intestinal barrier-related genes Muc2, Occludin and Zo-1 expression decreased (Ps < 0.05); serum glutathione and urine malondialdehyde significantly increased (Ps < 0.05); urine metabolome significantly changed and the variation was correlated with six SCFAs-producing bacteria, and some SCFAs including isobutyric acid, valeric acid and heptanoic acid decreased (Ps < 0.05). Therefore, the normal gut microbiome increases fecal arsenic excretion and biotransformation, which can maintain a healthier microbiome and metabolic functions, and alleviate the metabolic disorder for their mammal host under arsenic exposure.

The fecal arsenic excretion, tissue arsenic accumulation, and metabolomics analysis in sub-chronic arsenic-exposed mice after in situ arsenic-induced fecal microbiota transplantation.

Arsenic can be specifically enriched by rice, and the health hazards caused by high arsenic rice are gradually attracting attention. This study aimed to explore the potential of microbial detoxification via gut microbiome in the treatment of sub-chronic arsenic poisoning. We first exposed mice to high-dose arsenic feed (30 mg/kg, rice arsenic composition) for 60 days to promote arsenic-induced microbes in situ in the gastrointestinal tract, then transplanted their fecal microbiota (FMT) into another batch of healthy recipient mice, and dynamically monitored the microbial colonization by 16S rRNA sequencing and ITS sequencing. The results showed that in situ arsenic-induced fecal microbiome can stably colonized and interact with indigenous microbes in the recipient mice in two weeks, and established a more stable network of gut microbiome. Then, the recipient mice continued to receive high-dose arsenic exposure for 52 days. After above sub-chronic arsenic exposure, compared with the non-FMT group, fecal arsenic excretion, liver and plasma arsenic accumulation were significantly lower (P < 0.05), and that in kidney, hair, and thighbone present no significant differences. Metabolomics of feces- plasma-brain axis were also disturbed, some up-regulated metabolites in feces, plasma, and cerebral cortex may play positive roles for the host. Therefore, microbial detoxification has potential in the treatment of sub-chronic arsenic poisoning. However, gut flora is an extremely complex community with different microorganisms have different arsenic metabolizing abilities, and various microbial metabolites. Coupled with the matrix effects, these factors will have various effects on the efflux and accumulation of arsenic. The definite effects (detoxification or non-detoxification) could be not assured based on the current study, and more systematic and rigorous studies are needed in the future.

Application of zebrafish in the study of the gut microbiome.

Zebrafish (Danio rerio) have attracted much attention over the past decade as a reliable model for gut microbiome research. Owing to their low cost, strong genetic and development coherence, efficient preparation of germ-free (GF) larvae, availability in high-throughput chemical screening, and fitness for intravital imaging in vivo, zebrafish have been extensively used to investigate microbiome-host interactions and evaluate the toxicity of environmental pollutants. In this review, the advantages and disadvantages of zebrafish for studying the role of the gut microbiome compared with warm-blooded animal models are first summarized. Then, the roles of zebrafish gut microbiome on host development, metabolic pathways, gut-brain axis, and immune disorders and responses are addressed. Furthermore, their applications for the toxicological assessment of aquatic environmental pollutants and exploration of the molecular mechanism of pathogen infections are reviewed. We highlight the great potential of the zebrafish model for developing probiotics for xenobiotic detoxification, resistance against bacterial infection, and disease prevention and cure. Overall, the zebrafish model promises a brighter future for gut microbiome research.

BuFeiXiaoJiYin ameliorates the NLRP3 inflammation response and gut microbiota in mice with lung cancer companied with Qi-yin deficiency.

INTRODUCTION: NLRP3 inflammasome responses and gut microbiota have been shown an important role in lung cancer, however, the relationship between gut microbiota and NLRP3 inflammasome responses in lung cancer with Qi-yin deficiency remains elusive. METHODS: To investigate the effect of the traditional Chinese medicine BuFeiXiaoJiYin (BFXJY) on NLRP3 inflammasome responses and dysbiosis in lung cancer with Qi-yin deficiency, the female BALB/cA-nu mice were treated with LPS and ATP to induce inflammation, and were intragastrically treated with warm Chinese medicine and smoked with shavings to induce Qi-yin deficiency, as well as were injected with 1 × 107/ml A549 cells to simulate lung cancer. Then the three different doses of BuFeiXiaoJiYin (BFXJY) and positive control (CRID3) were used for intervention in mice for 27 consecutive days. Then, we estimated the protection effect of BFXJY on lung cancer mice with Qi-yin deficiency, through deterring tumor growth, NLRP3 inflammasome, PKC signaling, and homeostasis of gut microbiota. RESULTS: In this study, we found that BFXJY could inhibit the tumor growth in lung cancer with Qi-yin deficiency by reducing the production of IL-1ß and IL-18 and inhibiting NLRP3 inflammasome activation, which might be associated with the inhibition of PKC signaling. Furthermore, BFXJY could promote microbial diversity and balance the microbial composition changes induced by inflammation and Qi-yin deficiency in lung cancer. CONCLUSION: BuFeiXiaoJiYin ameliorates the NLRP3 inflammation response and gut microbiota in mice with lung cancer companied with Qi-yin deficiency. Our study provides a theoretical basis for the clinical development of therapeutic drugs targeting to treat lung cancer.

Attribution-Driven Explanation of the Deep Neural Network Model via Conditional Microstructure Image Synthesis.

The materials science community has been increasingly interested in harnessing the power of deep learning to solve various domain challenges. However, despite their effectiveness in building highly predictive models, e.g., predicting material properties from microstructure imaging, due to their opaque nature fundamental challenges exist in extracting meaningful domain knowledge from the deep neural networks. In this work, we propose a technique for interpreting the behavior of deep learning models by injecting domain-specific attributes as tunable "knobs" in the material optimization analysis pipeline. By incorporating the material concepts in a generative modeling framework, we are able to explain what structure-to-property linkages these black-box models have learned, which provides scientists with a tool to leverage the full potential of deep learning for domain discoveries.

In situ analysis of variations of arsenicals, microbiome and transcriptome profiles along murine intestinal tract.

In situ-based studies on microbiome-host interactions after arsenic exposure are few. In this study, the variations in arsenics, microbiota, and host genes along murine intestinal tracts were determined after arsenic exposure for two months. There was a gradual increase in the concentration of total As (CtAs) in feces from ileum to colon, whereas CtAs in the corresponding tissues were relatively stable. Differences in arsenic levels between feces and tissues were significantly different. The proportion of arsenite (iAsⅢ) in feces gradually decreased, however, it gradually increased in tissues. After arsenic exposure, the diversity and abundance of microbial community and networks in each segment were significantly dysregulated. Notably, 328, 579 and 90 differently expressed genes were detected in ileum, cecum, and colon, respectively. In addition, microbiome and transcriptome analyses showed a significant correlation between the abundance of Faecalibaculum and expressions of Plb1, Hspa1b, Areg and Duoxa2 genes. This implies that they may be involved in arsenic biotransformation. In vitro experiments using Biofidobactrium and Lactobacillus showed that probiotics have arsenic transformation abilities. Therefore, gut microbiome may modulate arsenic accumulation, excretion and detoxification along the digestive tract. Moreover, the abundance and diversity of gut microbiome may be related to the changes in host health.

Sub-chronic low-dose arsenic in rice exposure induces gut microbiome perturbations in mice.

Long-term consumption of arsenic-contaminated rice has become a public health issue that urgently needs to be addressed. In this study, mice were exposed to arsenic in rice (low dose, 0.91 mg/kg; medium dose, 9.1 mg/kg) for 30 days and 60 days, respectively, and the effects on pathological structures of spleen and skin, as well as the structure of the fecal microbiome were examined. The findings revealed dose/time cumulative effects on pathological changes, with even a low dose exposure for 30 days causing destruction of splenic follicular structure and thickening of dermal keratinized and epidermal layers. The Firmicutes/Bacteroidetes ratio in the community and the positive/negative ratio in network links were higher in arsenic groups, suggesting that arsenic resulted in a less healthy and unstable microbiome for the host. Thus lifetime consumption of arsenic in rice may have potential health effects on humans and must be carefully assessed to safeguard human health. Furthermore, in arsenic groups, arsenic-resistant bacteria or arsenic hazards remediation bacteria changed to be the dominant bacteria and acted as the core bacteria in the network modules. Some microbial arsenic transforming genes (arsC, arsR, arsA, ACR3, and aoxB) differed, indicating that the gut microbiome changed to withstand arsenic stress. Furthermore, Faecalibaculum, Lachnospiraceae_NK4A136_group, Angelakisella, Ruminiclostridium, and Desulfovibrionaceae are positively associated with arsenic dosage and may be useful in the early detection of arsenicals.

Structural characterization, anti-inflammatory and glycosidase inhibitory activities of two new polysaccharides from the root of Pueraria lobata.

Diabetes seriously endangers public health and brings a heavy economic burden to the country. Inflammation is one of the main inducing factors of type-2 diabetes (T2D) and may cause some complications of diabetes, such as diabetic encephalopathy and peripheral neuropathy. In-depth research and development of drugs to cure diabetes and complications are of great significance. Pueraria lobate is a medicinal herb used in several countries to treat many diseases. Here, two new polysaccharides (PLB-1-1 and PLB-1-2) were isolated and purified from the root of Pueraria lobata with molecular weights of 9.1 × 103 Da and 3.8 × 103 Da, respectively. The structure was evaluated by monosaccharide composition, GC-MS and NMR spectroscopy. It was determined that PLB-1-1 comprised →4)-α-d-Glcp-(1→, α-d-Glcp-(1→, →6)-ß-d-Galp-(1→, →3)-α-l-Araf-(1→, →3,6)-ß-d-Manp-(1→ and →4,6)-ß-d-Manp-(1→, and PLB-1-2 consisted of →4)-α-d-Glcp-(1→, ß-d-Glcp-(1→, →4,6)-ß-d-Glcp-(1→, →3,6)-ß-d-Manp-(1→ and α-l-Fucp-(1→. Furthermore, both PLB-1-1 and PLB-1-2 showed anti-inflammatory and inhibitory activities of α-glucosidase and α-amylase in vitro. Therefore, the new polysaccharides, i.e., PLB-1-1 and PLB-1-2, may be considered candidates for the treatment of diabetes and its related complications.

Microbial Diversity and Succession in the Chinese Luzhou-Flavor Liquor Fermenting Cover Lees as Evaluated by SSU rRNA Profiles.

The microbial diversity and the community succession in the fermenting cover lees of Chinese Luzhou-flavor liquor were investigated by small-subunit rRNA (SSU rRNA) culture independent method. All sequences retrieved from the 1, 7 and 60 days fermented cover lees were respectively assigned into the genera of Streptococcus, Acetobacter, Arthrobacter, Bacillus, Staphylococcus, Serratia, Nocardia, Methanoculleus, Clostridium, Aneurinibacillus, Corynebacterium, Lactobacillus, Microbacterium, Trichosporon, Saccharomycopsis, Sagenomella, Talaromyces, Eurotium, Issatchenkia, Zygosaccharomyces, Saccharomyces and TM7 phylum. The fungal Issatchenkia, Saccharomycopsis and Talaromyces and the bacteria Staphylococcus and Lactobacillus were most abundant in the 1 day fermented cover lees, the fungal Issatchenkia, Saccharomyces and Talaromyces and the bacteria Bacillus and Streptococcus were dominant in the 7 days cover lees, the archaea Methanoculleus and the fungal Eurotium and Talaromyces were prevalent in the 60 days cover lees. When the microbial community profiles in three samples were compared at species level, the prokaryotic community similarity coefficient was from 0.4042 to 0.5703 and descended to 0.2222, and that of eukaryotic community was from 0.3000 to 0.6000 and followed to 0.5215. These results suggested that microbial diversity variability and community succession have happened in the cover lees associated with fermentation proceeding and such variability and succession respond for the appearance of some unique flavor of Luzhou-flavor liquor.