Comparison of the in vitro metabolism of isoflavones by fecal flora from human flora‐associated mice and human

Recently there has been great interest in the biological effects of equol (4′,7‐dihydroxyisoflavan), a metabolite of daidzein produced by intestinal flora. In this study, the in vitro metabolism of daidzein, daidzin and genistein by fecal flora, in human flora‐associated (HFA) mice and a human donor was investigated. The in vitro incubation of feces with isoflavones demonstrated that the potential for equol production had been successfully transferred from human feces to HFA mice. The average equol concentrations were higher in feces from HFA mice than in those from their donor. In both HFA mice and their donor, the fecal equol production from daidzin was comparable to that from daidzein. The results suggest that daidzin would be an effective substrate for bacterial equol production in vivo. The HFA mice produced in these experiments and maintained in an isolated environment might also be useful for investigating the biological activity of equol in detail. Copyright © 2006 Society of Chemical Industry     

大豆异黄酮代谢终产物——雌马酚的研究进展

雌马酚是大豆异黄酮在人体肠道中的最终代谢产物。众多研究表明大豆异黄酮具有广泛的保健价值,在预防心血管疾病、乳腺癌和前列腺癌等方面均发挥重要作用。大豆异黄酮的生物活性在某种程度上归因于雌马酚,并且雌马酚具有较其前体更高的生物学效用。大豆异黄酮在特定的肠道菌作用下降解产生雌马酚,但并非每个人体内都可代谢产生雌马酚。总结了雌马酚在人体中的生理活性,并且综合论述了化学合成制备混合型雌马酚的方法,以及生物合成雌马酚过程中,动物及人体内可降解大豆异黄酮的肠道菌筛选情况。     

西藏牦牛发酵乳中乳酸菌及酵母菌的特性与相互作用

研究了西藏牦牛发酵乳中的优势菌株:发酵乳杆菌166A、乳酒假丝酵母37、酿酒酵母100、郎比克假丝酵母58在牛乳中的生长特性。探讨了发酵乳杆菌与酵母菌间的相互作用,在发酵过程中3株酵母菌均对发酵乳杆菌166A的生长有促进作用,发酵乳杆菌166A能抑制乳酒假丝酵母37的生长。酵母菌与发酵乳杆菌166A共同接种有利于保持产品冷藏期间活菌数的稳定,菌株之间可能存在共生作用。     

馥郁香型白酒对高脂饮食小鼠脂代谢及肠道菌群的影响

为探索馥郁香型白酒对高脂饮食小鼠脂质代谢及肠道菌群的影响,采用高脂饲料构建高脂小鼠模型,通过灌胃不同剂量的馥郁香型白酒,研究小鼠脏器、血脂相关指标和肠道菌群的变化。结果表明,适量饮用馥郁香型白酒能抑制高脂饲料引起的小鼠肝脏、附睾脂肪和肾周脂肪系数的升高及其相关脂质的积累,以及甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）和高密度脂蛋白胆固醇（HDL-C）的升高,提高肝脏内超氧化物歧化酶（SOD）活力（P＜0.05）。在属水平上,饮酒伴随高脂饮食缓解了高脂饮食引起的脱硫弧菌属（Desulfovibrio）相对含量的上升和罗斯氏菌属（Roseburia）相对含量的下降,显著增加了瘤胃球菌属（Ruminococcus）的相对含量（P＜0.05）,说明适量饮用馥郁香型白酒对高脂饮食造成的小鼠脂代谢异常和肠道菌群的失衡有一定的缓解作用。     

膳食结构对人体肠道微生物代谢的影响

选择120位志愿者参加试验,任意将其划分成高脂膳食结构组、高糖膳食结构组和高纤维膳食结构组3组,针对每种膳食结构受试者,随机将其划分成对照组和试验组。分析肠道微生物菌群变化,提取DNA,并进行PCR扩增与产物纯化处理,测试生物学指标。研究结果表明,高脂膳食结构能够使人体体重增加,促进肠道有害微生物的代谢,试验组受试者肠道微生物多样性比对照组高;试验组受试者体重明显高于对照组,高糖膳食结构能够令血糖值升高,对照组受试者肠道微生物多样性高于试验组,试验组样本厚壁菌门含量明显高于对照组,而拟杆菌门含量明显低于对照组;高纤维对照组与试验组丰富度、Shannon指数与均匀性无显著性差异,随着高纤维膳食结构处理时间的增加,拟杆菌门以及后壁菌门数量在一定程度上有所升高,而变形菌门细菌数量无显著改变。高脂、高糖膳食结构会促进有害微生物代谢,高纤维膳食结构会促进有益微生物代谢。     

富硒菌C5对小鼠肠道菌群结构的影响

研究了富硒菌C5和双歧杆菌三联活菌胶囊、地衣芽孢杆菌活菌胶囊的益生菌制剂对小鼠肠道菌群的影响。将小鼠分为益生菌制剂组A组（三联活菌组）和B组（地衣芽孢杆菌+三联活菌组）、实验组C组（富硒菌C5组）和空白组D组,饲养4周后取小鼠粪便,PCR扩增细菌16S rRNA基因的V3-V4区,用Ⅰllummina HiSeq 2500进行高通量测序,利用QIIME2软件生成不同分类水平上的物种丰度表,对样品Alpha多样性指数进行评估和Beta多样性分析。富硒菌C5和地衣芽孢杆菌活菌胶囊、双歧杆菌三联活菌胶囊一样能调节小鼠肠道菌群丰度和多样性,Alpha多样性的ACE、Chao1和Shannon均有所升高（P<0.05）;富硒菌C5能提高小鼠肠道菌群中Firmicutes（厚壁菌门）和Lactobacillus（乳杆菌属）的相对丰度;降低Staphylococcus（葡萄球菌属）;提高Lachnospiraceae（毛螺菌科）中的Agathobacter（无杆菌属）的相对丰度（P<0.05）。富硒菌C5能够改善机体的肠道微生态,在微生物制剂改善肠道菌群健康方面具有一定的应用价值。     

元宝枫籽油对高脂膳食小鼠脂代谢及肠道健康的影响北大核心CSCD

为了进一步开发与应用元宝枫籽油,研究了元宝枫籽油对高脂膳食小鼠脂代谢及肠道健康的影响。将60只小鼠分为空白组、模型组、元宝枫籽油高剂量组[1 200 mg/(kg·d)]和低剂量组[600 mg/(kg·d)],连续灌胃60 d。实验结束后,测定小鼠生长状况、血脂水平、盲肠微环境指标和盲肠内容物短链脂肪酸及微生物菌群。结果表明:与模型组相比,元宝枫籽油高剂量组能显著降低小鼠体质量、腰围、Lee′s指数、腹腔脂肪质量,显著降低小鼠盲肠内容物中游离氨、氨态氮、硫化氢和pH,显著增加盲肠内容物中丁酸、戊酸和丙酸的含量;元宝枫籽油高、低剂量组可显著降低小鼠血清中甘油三酯(TG)、总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-C)的水平,显著升高高密度脂蛋白胆固醇(HDL-C)水平,显著促进肠道有益微生物的生长,抑制有害菌的生长。因此,元宝枫籽油具有改善因高脂膳食引起的小鼠脂代谢紊乱和促进肠道健康的作用。     

海藻酸钠及其寡糖对小鼠脂质代谢和肠道菌群的影响

目的 研究海藻酸钠及其寡糖对小鼠脂质代谢和肠道菌群的影响。方法 利用C57BL/6小鼠制作高脂模型并灌喂海藻酸钠及其寡糖,通过检测体重、血脂等生理生化指标,观察肝脏及肠道组织病理变化,分析肠道菌群组成,判断海藻酸钠及其寡糖对脂质代谢和肠道菌群的影响。结果 海藻酸钠及其寡糖均会影响高脂小鼠的脂质代谢,抑制脂肪在肝脏中聚集,保护肠道绒毛形态使其能发挥正常功能;能够改善小鼠肠道菌群组成,提高肠道中乳酸杆菌和阿克曼菌等益生菌丰度,其中海藻酸钠寡糖对小鼠肠道菌群的改善作用更明显。结论 海藻酸钠寡糖或海藻酸钠可有效地改善小鼠的脂质代谢和肠道菌群紊乱。     

Development of a process for producing ethyl caproate‐ and ethyl lactate‐rich rice shochu

To increase the popularity of rice shochu, a process was developed to produce ethyl caproate‐ and ethyl lactate‐rich rice shochu. On a laboratory‐scale, there was a shochu production trial with Saccharomyces cerevisiae Y‐E. Caproic acid added in the second‐stage fermentation was esterified to ethyl caproate. Both ethyl caproate and ethyl lactate were produced by adding a caproic acid‐producing bacterial (CAPB) consortium and lactic acid bacterium (LAB) to the shochu production process. Yellow koji was more appropriate for producing a flavour‐rich shochu with the addition of a CAPB consortium and LAB than white koji. Optimal addition time for the CAPB consortium and LAB was on the first day of the second‐stage fermentation, judging from concentrations of ethyl caproate and ethyl lactate produced. Additional dosages of CAPB consortium and LAB positively affected the formation of ethyl caproate and ethyl lactate, respectively. Shochu production with the addition of 2% and 4% CAPB consortium led to ethyl caproate concentrations of 27.3 mg/L and 47.9 mg/L in genshu, respectively, and the shochu achieved the best sensory test score from the Japanese shochu brewery panellists. Copyright © 2015 The Institute of Brewing & Distilling     

Effects of soybean isoflavone on metabolism of rat osteoblasts and cytokines in vitro

The effects and mechanisms of soybean isoflavone on osteoblast (OB) proliferation in vitro were investigated. Fifty female Wistar rats were randomly divided into five groups with 10 rats in each group. Rat OBs were separated and cultured. The first generation of OBs cultured for 48 hr at various concentrations of isoflavone were set as the experimental groups, the OBs exposed to estradiol (E₂) culture were considered as positive control group. The biological characterization of OBs was investigated by phase contrast microscopy and alkaline phosphatase (ALP) histochemistry. The concentrations of interleukin (IL-1), osteoprotegerin (OPG), transforming growth factor (TGF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and vascular endothelial growth factor (VEGF) in isoflavone culture solutions were determined. Proliferation rate of OBs was increased in experimental group comparing that in the blank group. ALP activity in experimental group was higher than that in blank group. No significant differences of ALP activity were observed between E₂ culture group and isoflavone group at concentrations of 10⁻⁵ and 10⁻⁷ mM (P > 0.05). Furthermore, in the experimental groups at low isoflavone concentrations, the concentrations of OPG, TGF, and VEGF were increased and positively correlated with OB proliferation. However, the concentrations of IL-1, GM-CSF were decreased at higher concentration of isoflavone and were negatively correlated with OB proliferation. Soybean isoflavone could promote the growth and proliferation of rat OB, it might act as the stimulator of OPG, TGF, and VEGF pathway, and the inhibitor of IL-1, GM-CSF pathway as well.     

豆豉中主要分离细菌对小鼠生化指标及肠道菌群的影响

采用豆豉样品进行细菌分离培养和细菌16S rDNA基因PCR扩增、测序分析,并将分离所得细菌进行小鼠灌胃实验。结果显示,豆豉中的主要分离细菌为枯草芽孢杆菌、解淀粉芽孢杆菌、类肠膜魏斯氏菌、乳酸片球菌、戊糖片球菌、发酵乳杆菌、表皮葡萄球菌。并且,各菌对小鼠丙氨酸转氨酶(ALT)、天门冬氨酸氨基转移酶(AST)、总胆红素(TBIL)、直接胆红素(DBIL)、肌酐(CREA)、尿素氮(BUN)、尿酸(UA)、血糖(GLU)、甘油三酯(TG)、总胆固醇(TC)各项生化指标基本无影响。然而,其中解淀粉芽孢杆菌DC02能极显著性地降低小鼠血糖(GLU)水平,该菌有望成为治疗糖尿病的潜在菌株。活菌计数结果表明,除表皮葡萄菌以外,豆豉中分离所得其它细菌均能改善肠道菌群结构。可见,豆豉中分离所得主要细菌对正常机体安全、无致病性。      

偏钒酸钠促进大豆芽异黄酮类物质黄豆苷元和染料木黄酮合成的研究

目的:分析比较偏钒酸钠对大豆芽合成异黄酮类物质-黄豆苷元和染料木黄酮的影响;方法:将大豆种子在不同浓度的偏钒酸钠水溶液(0、200、400、600、800、1000、1200、1400、1600mg/LNaVO3)于28℃萌发6d,第6d收获富钒大豆芽,洗净烘干至恒重,用95%乙醇提取大豆芽中的异黄酮类物质-黄豆苷元和染料木黄素,黄豆苷元和染料木黄素含量由高效液相色谱法测定;结果:分析测定结果表明,当大豆种子在浓度为200～600mg/L偏钒酸钠溶液中于28℃萌发6d,收获的大豆芽中的异黄酮类物质黄豆苷元和染料木黄酮的含量高于同等条件下其他浓度偏钒酸钠萌发液中萌发的大豆芽;结论:综合大豆芽的生长情况及大豆芽中异黄酮类物质-黄豆苷元和染料木黄酮含量等因素,在本实验条件下,萌发富钒大豆芽的适宜偏钒酸钠酸浓度为200～600mg/L,适宜的培育时间为96～120h,适宜温度为28℃。     

Gas‐producing and spoilage potential of Enterobacteriaceae and lactic acid bacteria isolated from chilled vacuum‐packaged beef

This study aimed to enumerate and identify lactic acid bacteria and Enterobacteriaceae from spoiled and nonspoiled chilled vacuum‐packaged beef and determine their potential to cause blown pack spoilage. These microbial groups were also enumerated in nonspoiled samples and detected in abattoir samples. The potential of isolates to cause ‘blown pack’ spoilage of vacuum‐packaged beef stored at chilled temperature (4 °C) and abuse temperature (15 °C) was investigated. Populations of lactic acid bacteria in exudate of spoiled and nonspoiled samples were not significantly different (P > 0.05), whereas the number of lactic acid bacteria on the surface was significantly higher (P < 0.05) in spoiled samples as compared to nonspoiled samples. The population of Enterobacteriaceae species in exudate and on the surface of samples were significantly higher (P < 0.05) in spoiled packs in comparison with nonspoiled packs. Results of the deterioration potential showed that ‘blown pack’ spoilage was noticeable after 7 days at 15 °C and after 6 weeks at 4 °C for samples inoculated with Hafnia alvei.     

基于NRPS基因筛选鉴定产生环脂肽葡萄附生细菌的研究

本研究采用平板稀释法和斜面分离纯化技术,从夏黑葡萄中筛选分离到5株附生细菌,提取菌株的基因组DNA,PCR扩增16S r DNA序列,产物纯化后进行克隆测序,利用MEGA 6.0软件对序列进行同源性比对分析,构建系统进化树后,将5株附生细菌分别鉴定为克雷伯肺炎杆菌（Klebsiella pneumoniae）、枯草芽孢杆菌（Bacillus subtilis）、克考氏菌（Kocuria marina）、嗜气芽孢杆菌（Bacillus aerophilus）、类芽孢杆菌（Paenibacillus agaridevorans）。在此基础上,以非核糖体多肽合成酶基因（non-ribosomal peptide compounds synthetase,NRPS）为靶点,筛选到含有目的条带的菌株PTWA2,经系统发育树预测该菌株能够产生环脂肽类化合物。该菌株发酵产物经有机溶剂萃取、常压硅胶柱层析、Sephedex LH-20等分离手段纯化得到一个单体化合物,采用核磁共振和质谱方法鉴定该化合物为环脂肽Surfactin A。该研究结果为以功能基因定向筛选产生环脂肽化合物的菌株提供了新的研究方法与理论依据。      

一株源于北派酱香白酒酿造环境中产淀粉酶细菌的筛选、鉴定及其特性研究

采用平板涂布法从酱香型白酒酿造环境（大曲、酒醅和窖泥）筛选产淀粉酶细菌菌株,通过菌落形态、细胞显微结构、生理生化特性和分子生物学方法对其进行鉴定,并对其生长特性及耐受性进行研究。结果表明,从酱香型白酒大曲中筛选得到一株产淀粉酶的细菌,编号为2-2,经鉴定菌株2-2为解淀粉芽孢杆菌（Bacillus amyloliquefaciens）。菌株2-2能够在25～45 ℃和pH 5～9范围内生长良好,属于乙醇高耐受性菌株,在乙醇体积分数为12%时仍能生长,并具有较高的NaCl和葡萄糖耐受性,最高耐受质量分数分别为15%和70%。菌株2-2在高粱酶解液中能产生酱香型白酒中的多种重要风味物质,如苯乙醇、糠醇3-羟基-2-丁酮、2,5-二甲基吡嗪和乙烯基愈创木酚等,是酱香型白酒酿造中重要的功能菌株。     

叔丁基对苯二酚对小鼠肠道菌群的影响

目的 研究食品添加剂叔丁基对苯二酚(tert-butylhydroquinone, TBHQ)对小鼠肠道菌群的影响。方法 BALB/c小鼠随机分为空白对照组和TBHQ处理组, 分别饮用纯水和TBHQ溶液(200 mg/L)。干预5周后, 利用酶联免疫吸附试验(enzyme linked immunosorbent assay, ELISA)测定小鼠血液样本炎症因子水平; 收集两组小鼠的粪便, 利用16S rDNA扩增子高通量测序分析肠道微生物群落结构和组成变化, 判断TBHQ对肠道菌群的影响。结果 与对照组相比, TBHQ处理显著降低了小鼠肠道疣微菌门(Verrucomicrobia)、拟杆菌门(Bacteroidetes)、阿克曼氏菌(Akkermansia)、瘤胃球菌属(Ruminococcus)等菌的相对丰度, 提高了厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、毛罗菌属(Lachnospira)、螺杆菌属(Helicobacter)等微生物的相对丰度。结论 本研究剂量TBHQ显著影响了小鼠的肠道菌群组成, 该变化对机体健康的影响有待进一步研究。