基于16S rRNA技术分析当归超微粉对小鼠肠道菌群多样性的影响

研究不同剂量当归超微粉对小鼠肠道菌群多样性、肠道生理结构的作用。将C57BL/6小鼠分为当归超微粉高剂量组(2.0g/kg)、中剂量组(1.0 g/kg)、低剂量组(0.5 g/kg)、传统饮片组(2.0 g/kg)、传统粉末组(2.0 g/kg)和空白组,灌胃给药15 d,记录体重,在灌喂第15 d时无菌取结肠内容物,扩增肠道菌群16S rRNA基因的V3+V4区,采用高通量测序分析β多样性和α多样性、分析门水平和属水平的物种组成,HE染色法观察胃肠道病理变化。结果显示,C57BL/6小鼠体重正常生长,当归超微粉饮片高剂量组的对小鼠肠道微生物的疣微菌门(Verrucomicrobia)含量显著增加(p<0.05),放线菌门(Actinobacteria)含量减少(p<0.01)。另外,当归超微粉饮片中剂量组拟杆菌门(Bacteroidetes)含量降低最为显著,厚壁菌门(Firmicutes)增加最为显著;在属水平中剂量Faecalibaculum增加最明显(p<0.05),故超微粉的中剂量为最佳实验剂量。各处理组小鼠胃肠道无病理变化。本实验可为当归以超微粉的使用方式,对人体保健或治疗使用的科学用量和安全性,提供理论依据。另外,可为以肠道菌群相关的有效性提供技术支持。     

Green Tea Formulations with Vitamin C and Xylitol on Enhanced Intestinal Transport of Green Tea Catechins

The effect of green tea formulated with vitamin C and xylitol on intestinal cell transport of gallated and nongallated catechin was studied. The transport of catechins from both apical to basolateral and basolateral to apical directions was measured. The effect of vitamin C (4, 10, 20 ppm), xylitol (11, 27.5, 55 ppm), and combinations of both on the intestinal transport rate of catechins was examined. The efflux value (Pb→a/Pa→b) of (–)‐epigallocatechin (EGC), (–)‐epigallocatechin gallate (EGCG), (–)‐epicatechin (EC), and (–)‐epicatechin gallate (ECG) was 0.26, 0.22, 1.22, and 0.17, respectively, indicating that EC appeared to be less absorbed compared with other catechins. The addition of xylitol (11, 27.5, 55 ppm) and vitamin C (4, 10, 20 ppm) and in combination enhanced transport rate of nongallated catechins such as EC and EGC. For EC, vitamin C was revealed to be the most effective on intestinal transport, implying the inhibition of the efflux transport mechanism of EC. Intestinal transport of gallated catechins significantly increased from catechins formulated with vitamin C and xylitol in a dose‐dependent manner compared to the catechin‐only formulation. Results provide a potential strategy to enhance the delivery and bioavailability of catechins in humans by modulating green tea formulation with vitamin C and xylitol.     

膳食纤维与肠道微生物及相关疾病的研究进展

肠道微生物与人体长期共生,且与人体健康和疾病密切相关,膳食纤维通过改变肠道微生物的种类与数量,间接影响其在肠道中的代谢产物,进而影响人体的健康与疾病。肠道微生物与膳食纤维密切合作,对人体健康的影响意义重大。本文介绍了膳食纤维的定义、膳食纤维的生理功能、膳食纤维的最适摄入量、肠道微生物及其生理功能、膳食纤维对肠道微生物的影响、膳食纤维及肠道微生物对肥胖、炎症、结直肠癌、妊娠合并症及心脑血管疾病的影响,为通过调整膳食纤维治疗疾病的实践提供参考。     

Intentionally induced intestinal barrier dysfunction causes inflammation,affects metabolism,and reduces productivity in lactating Holstein cows

Study objectives were to evaluate the effects of intentionally reduced intestinal barrier function on productivity, metabolism, and inflammatory indices in otherwise healthy dairy cows. Fourteen lactating Holstein cows (parity 2.6 ± 0.3; 117 ± 18 d in milk) were enrolled in 2 experimental periods. Period 1 (5 d) served as the baseline for period 2 (7 d), during which cows received 1 of 2 i.v. treatments twice per day: sterile saline or a gamma-secretase inhibitor (GSI; 1.5 mg/kg of body weight). Gamma-secretase inhibitors reduce intestinal barrier function by inhibiting crypt cell differentiation into absorptive enterocytes. During period 2, control cows receiving sterile saline were pair-fed (PF) to the GSI-treated cows, and all cows were killed at the end of period 2. Administering GSI increased goblet cell area 218, 70, and 28% in jejunum, ileum, and colon, respectively. In the jejunum, GSI-treated cows had increased crypt depth and reduced villus height, villus height-to-crypt depth ratio, cell proliferation, and mucosal surface area. Plasma lipopolysaccharide binding protein increased with time, and tended to be increased 42% in GSI-treated cows relative to PF controls on d 5 to 7. Circulating haptoglobin and serum amyloid A concentrations increased (585- and 4.4-fold, respectively) similarly in both treatments. Administering GSI progressively reduced dry matter intake (66%) and, by design, the pattern and magnitude of decreased nutrient intake was similar in PF controls. A similar progressive decrease (42%) in milk yield occurred in both treatments, but we observed no treatment effects on milk components. Cows treated with GSI tended to have increased plasma insulin (68%) and decreased circulating nonesterified fatty acids (29%) compared with PF cows. For both treatments, plasma glucose decreased with time while β-hydroxybutyrate progressively increased. Liver triglycerides increased 221% from period 1 to sacrifice in both treatments. No differences were detected in liver weight, liver moisture, or body weight change. Intentionally compromising intestinal barrier function caused inflammation, altered metabolism, and markedly reduced feed intake and milk yield. Further, we demonstrated that progressive feed reduction appeared to cause leaky gut and inflammation.     

人体肠道菌群对大豆皂苷Ⅱ的体外代谢转化

为考察人体肠道菌群对大豆皂苷Ⅱ的体外代谢转化作用,在牛脑牛心培养液(BHI)和磷酸盐缓冲液(PBS)两种离体模型下,研究了大豆皂苷Ⅱ在48 h内被肠道菌群代谢转化过程,并用HPLC/MS系统对其转化产物进行分析鉴定。结果显示,大豆皂苷Ⅱ先被菌群酶转化为大豆皂苷Ⅳ,在48 h被最终转化为大豆皂苷元B,表明大豆皂苷在肠道微生物作用下,其糖基被逐步水解生成相对分子质量更小、疏水性更强的代谢物。     

Effects of Enterococcus faecium (SF68) on immune function in mice

Probiotics exert health benefits on human and animals when administered in adequate amounts. The objective of this study was to assess the effects of Enterococcus faecium (SF68) on intestinal colonisation and immune function of BALB/c mice. Six-week-old female BALB/c mice were orally administered with E. faecium (SF68). Results showed that the total anaerobe and lactobacilli in the faeces increased (P < 0.05), while the number of faecal enterobacteria decreased (P < 0.05) in E. faecium-fed mice. Furthermore, supplementation of E. faecium (SF68) increased the percentage of double positive (DP) cells in peripheral blood, the concentration of plasma IgG, and the levels of interleukin-4 (IL-4), interleukin-6 (IL-6) and interferon-γ (IFN-γ) in splenocytes of the mice (P < 0.05). This study demonstrated that E. faecium SF68 affects the intestinal microbial flora and modulates the immune responses, which indicates a viable probiotic characteristic of E. faecium SF68 in modification of immune function.     

多酚通过肠道菌群调节能量代谢研究进展

多酚是一类植物次生代谢产物,广泛存在于人类膳食中,一般可分为3大类：酚酸类、聚合单宁类和黄酮类。多酚以及其被肠道菌群代谢的产物,能选择性调节肠道中易感微生物的生长,选择性的促进有益菌群(如乳酸菌)生长,抑制有害菌的增殖,也即引发肠道微生态的改变。这种改变对宿主产生重要影响,对宿主能量代谢的影响可能通过如下实现：1)肠道内微生物数量和种类的变化,改变微生物代谢及产酶的种类和数量;2)多酚代谢产物还可与细菌细胞表面作用,抑制酶的活性,从而影响能量代谢,减少脂肪沉积;3)多酚通过干预人体肠道菌群调整能量代谢,为预防和治疗肥胖及相关性疾病提供了新的研究思路。本文对多酚调整肠道菌群从而影响肥胖发生的作用机制进行了综述。     

人乳与牛乳N-链寡糖组对小鼠肠道菌群的影响

目的:探究人乳N-链寡糖组(human milk N-glycome,HMN)与牛乳N-链寡糖组(bovine milk N-glycome,BMN)对小鼠肠道菌群的影响.方法:以C57BL/6J雄性小鼠为对象,首先在体外测定粪便菌群中与N-链寡糖相关的糖苷酶活性,并模拟粪便菌群对HMN与BMN的利用;然后将小鼠随机分...     

Ⅱ型糖尿病与肠道菌群及益生菌的相关性研究进展

Ⅱ型糖尿病是一种常见的慢性代谢性疾病,其发病机制十分复杂,其中肠道菌群在其发病早期和加重过程中都起着重要的作用。益生菌作为调节肠道菌群的有效手段,可以通过改善肠道通透性、调节血脂、增强机体免疫力等多种机制对II型糖尿病起到预防和改善作用。现就近年来肠道菌群和2型糖尿病的相关性以及益生菌的作用研究进展作一综述。