Acarbose and voglibose are the most widely used diabetes drugs as glycosidase inhibitors. In this study, the use of these two inhibitors significantly increased the content of starch in large intestine, and altered the concentration of short-chain fatty acids (SCFAs) by affecting the intestinal microbiota. However, there are some differences in the intestinal microbiome of the two groups of mice, mainly in bacteria such as Bacteroidaceae bacteroides and Desulfovibrionaceae desulfovibrio. The productions of acetate and propionate in caecum in voglibose group were significantly higher than those in acarbose group and two kinds of glycosidase inhibitors were close in the production of butyrate in caecum. The Tax4Fun analysis based on Kyoto Encyclopedia of Genes and Genomes (KEGG) data indicated that different productions of acetate and propionate between acarbose group and voglibose group may be related to 2-oxoisovalerate dehydrogenase and pyruvate oxidase. In addition, in-vitro experiments suggested that voglibose had less effect on epithelial cells than acarbose after direct stimulation. According to the recent researches of SCFAs produced by intestinal microbiota, our comparative study shown higher concentration of these beneficial fatty acids in the lumen of voglibose-treated mice, which implied a lower level of inflammation.Key words acarbose; voglibose; microbiota; short-chain fatty acid; Tax4FunWith the increasing number of obesity and diabetes around the world, there are more and more different classes of medications to treat diabetes, such as biguanides (metformin), sulfonylureas, insulin, glucagon-like peptide 1 (GLP-1) agonists, dipeptidyl peptidase IV inhibitors, thiazolidinediones and sodium-glucose transporter 2 inhibitors (to name a few). 1) However, acarbose and voglibose as part of α-glucosidase inhibitors (AGIs) are another class of anti-diabetic medications. As first-line hypoglycemic drugs used in patients with type 2 diabetes especially in Asian since their diet meals contain high content of carbohydrates, acarbose and voglibose can typically reduce postprandial glucose level by delaying carbohydrate digestion in the gut, so they can be a useful treatment in the patients who raised basal glucose concentrations slightly and marked postprandial hyperglycemia. 2) In addition, there will also be some side effects, mainly reflected in gastrointestinal flatulence, loose stool and so on. The main reason for this is that fermentation of undigested carbohydrates by bacteria produced gas in the colon. 3) Acarbose and voglibose treatment delayed starch digestion in the small intestine but there was compensatory salvage through bacterial fermentation in the large intestine. 4) When carbohydrates (starch, dietary fiber) enter the large intestine, they are degraded by the fermentation of anaerobic flora. 5) Under normal diet situations, the better part of starch was digested and absorbed in the small intestine, therefore, extra starch entering the large bowel changed microbial eco-system to some degree. Som...

Background Arbuscular mycorrhizal fungi (AMF) have a positive effect on drought tolerance of plants after establishing reciprocal resymbiosis with roots, while the underlying mechanism is not deciphered. Metabolomics can explain the mechanism of plant response to environmental stress by analyzing the changes of all small molecular weight metabolites. The purpose of this study was to use Ultra High Performance Liquid Chromatography Q Exactive Mass Spectrometer to analyze changes in root metabolites of walnut (Juglans regia) after inoculation with an arbuscular mycorrhizal fungus Diversispora spurca under well-watered (WW) and drought stress (DS). Results Sixty days of soil drought significantly inhibited root mycorrhizal colonization rate, shoot and root biomass production, and leaf water potential in walnut, while AMF inoculation significantly increased biomass production and leaf water potential, accompanied by a higher increase magnitude under DS versus under WW. A total of 3278 metabolites were identified. Under WW, AMF inoculation up-regulated 172 metabolites and down-regulated 61 metabolites, along with no changes in 1104 metabolites. However, under DS, AMF inoculation up-regulated 49 metabolites and down-regulated 116 metabolites, coupled with no changes in 1172 metabolites. Among them, juglone (a quinone found in walnuts) as the first ranked differential metabolite was up-regulated by AMF under WW but not under DS; 2,3,5-trihydroxy-5–7-dimethoxyflavanone as the first ranked differential metabolite was increased by AMF under DS but not under WW. The KEGG annotation showed a large number of metabolic pathways triggered by AMF, accompanied by different metabolic pathways under WW and DS. Among them, oxidative phosphorylation and phenylalanine metabolism and biosynthesis were triggered by AMF in response to WW and DS, where N-acetyl-L-phenylalanine was induced by AMF to increase under DS, while decreasing under WW. Conclusion This study provides new insights into the metabolic mechanisms of mycorrhiza-enhanced drought tolerance in walnuts.

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Walnuts are an economically important forest tree used for timber and nut production, and the nut of fruits is rich in various nutrients, becoming one of the four important nuts in the world. Walnuts have deep roots, which can be colonized by either ectomycorrhizal fungi or arbuscular mycorrhizal fungi in the soil. These mycorrhizal fungi form beneficial symbioses in roots of walnut. A large number of ectomycorrhizal fungi have been identified, whilst Boletus edulis, Calvatia uiacina, and Cantharelles cibarius isolated from walnut orchards stimulated plant growth and gave the capacity of stress tolerance in walnut. Moreover, Carya illinoensis is a very good host plant for commercial production of truffles, especially Tuber indicum. In addition, ectomycorrhizal fungi accelerate plant growth and enhance potential stress tolerance of walnuts. Inoculation with arbuscular mycorrhizal fungi also showed the improvement of plant growth and nutrient acquisition of walnut, the enhancement of drought tolerance in walnut, nutrient redistribution under walnut interplanting patterns, and the delivery of juglone by mycorrhizal hyphae. A culturable in vitro arbuscular mycorrhizal like fungus Piriformospora indica also enhanced salt tolerance of walnut plants. In this mini-review, the physiological roles of mycorrhizal fungi, including arbuscular mycorrhizal fungi, ectomycorrhizal fungi and arbuscular mycorrhizal like fungus (P. indica) on walnut plants are summarized, and future outlooks in the field are proposed.