Bioscience of Microbiota, Food and Health最新文献

Atherosclerosis is the main cause of cardiovascular diseases, and healthy dietary habits are a feasible strategy to prevent atherosclerosis development. Camellia oil, an edible plant oil, exhibits multiple beneficial cardiovascular effects. Our previous study showed that oral administration of camellia oil attenuated hyperglycemia, fat deposits in the liver, and the atherosclerosis index in high-fat diet (HFD)-induced obese mice. Here, an atherosclerosis model of apolipoprotein E (ApoE)^-/- mice induced by HFD was used to study the effect of camellia oil on atherosclerosis, and 16S rRNA gene sequencing was used to analyze the changes in gut microbiota composition. The results showed that camellia oil significantly inhibited the formation of atherosclerotic plaques in ApoE^-/- mice, which were characterized by significantly reduced levels of serum total cholesterol and enhanced levels of serum high-density lipoprotein cholesterol. The aortic levels of interleukin-6 and tumor necrosis factor were decreased. The results of the 16S rRNA analysis showed that after camellia oil interventions, the intestinal flora of ApoE^-/- mice changed significantly, with the diversity of intestinal flora especially increasing, the relative abundances of Bacteroides, Faecalibaculum, Bilophila, and Leuconostoc increasing, and the Firmicutes/Bacteroidetes ratio and Firmicutes abundance decreasing. Collectively, our findings confirmed the promising value of camellia oil in preventing the development of atherosclerosis in ApoE^-/- mice. Mechanistically, this preventive effect of camellia oil was probably due to its lipid-lowering activity, anti-inflammatory effects, and alteration of the gut microbiota composition in the mice.

Quercetin, a flavonol present in many vegetables and fruits, has been identified as a chemoprevention agent in several cancer models. However, the molecular mechanism of quercetin's anticancer activity is not entirely understood. MicroRNAs (miRNAs), small noncoding RNAs, have been reported to play key roles in various biological processes by regulating their target genes. We hypothesized that quercetin can exert an anticancer effect through the regulation of miRNAs. To test this hypothesis, we investigated the effects of quercetin on the expression of tumor-suppressive miRNAs in cervical cancer. Quercetin up-regulated the in vivo and in vitro expression of tumor-suppressive miRNAs miR-26b, miR-126, and miR-320a. Quercetin suppressed the level of β-catenin, encoded by catenin beta 1 (CTNNB1), by up-regulating miR-320a in HeLa cells. Moreover, quercetin increased the expression of mir-26b, mir-126, and mir-320a precursors in HeLa cells. The results from this study show that quercetin has the potential to prevent cervical cancer by regulating the expression of tumor-suppressive miRNAs.

Tannins (TAs) are an anti-nutritional substance commonly used as a natural feed additive for livestock. However, our previous study described the dose-dependent adverse effects of TA on immune responses and growth in chickens. In this study, we evaluated the protective effects of a probiotic preparation (BT) consisting of three different bacteria (Bacillus mesenteric, Clostridium butyricum, and Streptococcus faecalis) against TA-induced immunosuppression in chickens. Forty chicks were divided into 4 groups as follows: the CON group (basal diet), BT group supplemented with 3 g BT/kg diet, tannic acid (TA) group supplemented with 30 g TA/kg diet, and BT+TA group supplemented with 3 g BT/kg diet + 30 g TA/kg diet. The feeding trial lasted for 35 days. Lymphocyte subset, macrophage phagocytosis, cytokine mRNA expression, and primary and secondary IgY immune responses were evaluated. BT supplementation significantly improved TA-induced reductions in final body weight, body weight gain, feed intake, and relative weights of lymphoid organs compared with the TA group. Furthermore, in the spleen and cecal tonsil (CT), the relative populations of CD4⁺, CD8⁺, and CD4⁺CD8⁺ cells in the BT+TA group were significantly ameliorated compared with the TA group. Additionally, comparison with the TA group showed that the chickens in the BT+TA group had an improved relative population of B cells in the CT and that macrophage phagocytosis in the spleen was significantly increased. Chickens in the BT+TA group showed significant increases in IFN-γ and IL-4 mRNA expression in the spleen compared with the TA group. The primary and secondary IgY responses were significantly improved. These results revealed that supplementation with BT protects against TA-induced immunosuppression in chickens.

The increase of lifestyle-related diseases in Asia has recently become remarkably serious. This has been associated with a change in dietary habits that may alter the complex gut microbiota and its metabolic function in Asian people. Notably, the penetration of modern Western diets into Asia, which has been accompanied by an increase in fat content and decrease in plant-derived dietary fiber, is restructuring the Asian gut microbiome. In this review, we introduce the current status of obesity and diabetes in Asia and discuss the links of changes in dietary style with gut microbiota alterations which may predispose Asian people to metabolic diseases.

The biological activities of acetic acid bacteria (AAB) as Gram-negative bacteria have attracted our interests, especially in their inhibitory effects on allergic responses. To clarify the underlying mechanism that improves allergic symptoms by ingestion of the AAB Gluconacetobacter hansenii, we examined whether different extracts of heat-killed G. hansenii GK-1 could reduce the interleukin (IL)-4 production of immune cells from food-allergic model of OVA23-3, transgenic mice with ovalbumin (OVA)-specific T-cell-receptor genes. A hot-water extract fraction (FII) of G. hansenii GK-1 significantly decreased the in vitro IL-4 production of spleen cells of OVA23-3 mice compared with those stimulated with OVA alone. The IL-4 inhibitory effect was also observed for FIV (purified lipopolysaccharide (LPS) fraction), but the activity was lower than for FII or LPS from Escherichia coli. Unlike LPS from Escherichia coli, FIV significantly inhibited the LPS-induced IL-6 production of the spleen cells. The addition of FII or FIV to a Foxp3⁺T cell-inducing culture showed that FII significantly promoted the rate of Foxp3⁺CD4⁺T cells of OVA-stimulated mesenteric lymph node cells from recombination-activating-gene (RAG)-2-deficient food-allergic inflammatory OVA23-3 (R23-3) mice with suppression of IL-4 production, while FIV induced Foxp3⁺T cells from RAG-2-deficient DO11.10 non-inflammatory mice. Structure analysis showed a lack of O-antigen in FIV, which seemed to lead to the weak biological activities of FIV observed. The present study suggests that extracts of G. hansenii GK-1 to inhibit IL-4 production of immune cells and/or promote regulatory T cell differentiation synergistically play important roles in improving allergic symptoms safely as well as normal condition.