人体肠道微生物对十溴联苯醚的代谢研究

十溴联苯醚(BDE209)是一种具有持久性有机污染物特征的溴系阻燃剂, 可在生物体代谢生成更高毒性的化合物. 本文利用从人体粪便中提取的微生物以及通过人体肠道微生态系统模拟装置培养的人体肠道微生物, 在体外条件下研究BDE209 在人体肠道微生物作用下的代谢. 结果表明在为期10 d 的反应时间里, BDE209 含量保持稳定, 在气相色谱-质谱联用仪(GCNCI-MS)的色谱图中也没有检测到可能的脱溴代谢产物, 说明BDE209 没有发生显著的脱溴代谢作用.     

The potential role of endogenous bacteriophages in controlling invading pathogens

Bacteriophages (phages) are omnipresent in our environment, and recent studies highlight their potential impact on the microbial world. Phages can also be present in mammalian organisms, including man (intestines, oral cavity, urine, sputum and serum). Data are available which suggest that those endogenous phages could play an important role in eliminating bacteria and regulating the body ecosystem. Furthermore, our most recent findings suggest that phages can exert immunosuppressive action in the gut, helping control local inflammatory and autoimmune reactions, and demonstrate anticancer activity. We hypothesize that phages could act in concert with the immune system in immunosurveillance against bacteria, viruses and cancer.article dedicated to Professor Ludwik Hirszfeld to commemorate the 50^th anniversary of his deathReceived 8 September 2004; received after revision 18 October 2004; accepted 21 October 2004     

Effect of dexamethasone on Fc γ receptor expression in foetal and neonatal rat gut

Summary When injected into 12-day-old suckling rats, dexamethasone caused a precocious disappearance of Fc receptors from enterocytes of the proximal small intestine. However, dexamethasone appeared to be necessary for the maintenance or production of such receptors in foetal rat gut cultured in vitro.Supported by an award from the Science and Engineering Research Council.     

Effect of long acting somatostatin-analogue,SMS 201995, on gut hormone secretion in normal subjects

Summary SMS 201 995 is a new long acting analogue of somatostatin. We have investigated its effect on basal and meal stimulated secretion of gut hormones and have shown that after a single s. c. injection of 50 g it lowers significantly the basal plasma levels of pancreatic polypeptide, secretin, motilin, pancreatic glucagon and insulin, it also effectively suppresses the postprandial release of pancreatic polypeptide, gastrin, secretin, gastric inhibitory peptide, pancreatic glucagon and insulin. Except for the usual brief discomfort of an injection, no symptoms or untoward effects were observed.     

双歧杆菌对慢性腹泻猕猴肠道微生物组的影响

本研究旨在结合高通量测序和平板计数实验探索含活性双歧杆菌(Bifidobacterium spp)的饲料对慢性腹泻猕猴(Macaca mulatta)肠道微生物多样性及其腹泻症状的影响.通过16S rRNA高通量测序对比分析添加双歧杆菌前后饲料的菌群组成,发现添加组双歧杆菌的相对丰度显著高于未添加组(P<0.05).向慢性腹泻猕猴投喂该饲料,一个月后收集粪便进行宏基因组测序,并与前期研究获得的未添加组慢性腹泻猕猴和健康猕猴的肠道宏基因组数据对比分析,发现添加组的肠道菌群中乳杆菌(Lactobacillus spp)相对丰度较未添加组显著上调(P<0.05),与健康组无显著差异(P>0.05).最后对饲喂双歧杆菌后好转及持续腹泻猕猴的粪便进行乳杆菌平板计数实验.发现经饲喂,猕猴肠道中乳杆菌数量增加,验证了宏基因组测序分析的结果.     

胃肠激素对胃运动的影响

本研究将胃肠运动的体液性调节机制即胃肠激素对胃运动的影响进行了实验研究,结果显示：血清素和胃动素对麻醉状态下的家兔的胃运动有明显的促进作用,且作用时间持久。说明血清素和胃动素对胃肠运动起着重要的调节作用。     

肠道菌群：膳食与健康研究的新视角

近年来,随着“人类微生物组计划”、“肠道元基因组计划”等研究项目的开展,人类对肠道菌群的关注达到了空前的高度。随着对其结构和功能的不断挖掘,人们发现肠道菌群与宿主健康密切相关,甚至被认为是“被忽略的人体器官”。最新的研究报道表明,包括帕金森病、乳腺癌、艾滋病、肝硬化、肾病、关节炎、糖尿病等在内的疾病都与肠道微生物结构异常相关;同时最近有很多研究从肠道菌群的角度关注了食品甜味剂、食品乳化剂、节食等因素对机体的影响;另外,肠道菌群也已成为我们阐释益生菌、益生元、微量元素、多酚化合物等膳食因子调控健康研究的着眼点。可以预见,随着肠道微生物研究方法和手段的不断发展,肠道菌群有可能成为多种疾病预测诊断的标志物;同时,许多人类疾病的发病机制及干预机制、食物保健功能等将有可能通过肠道微生态理论而得到更好地诠释和补充。     

体外模拟人肠道微生物对葡萄酒花色苷稳定性的影响

分析肠道微生物对葡萄酒花色苷稳定性的影响及花色苷结构与稳定性的关系,旨在为花色苷的消化吸收和提高葡萄酒花色苷生物利用率提供指导。采集健康受试者的肠道微生物,利用体外培养方法混合培养肠道微生物与赤霞珠红葡萄酒样品24h,分别于0、4、12、24h取样进行花色苷的高效液相色谱分析。结果表明,肠道微生物促进葡萄酒花色苷的降解。与肠道微生物共培养24h后,葡萄酒总花色苷的降解率达到19.10%,而对照组仅为9.57%;肠道微生物作用下,葡萄酒中5种基本花色苷的降解水平均高于无菌对照组,但不同处理间没有显著差异;对比无菌对照组,葡萄酒中3种酰化花色苷含量在肠道菌群的作用下显著降低。花色苷B环取代基与酰基种类影响花色苷的稳定性。B环羟基数量增加,花色苷稳定性下降;B环甲氧基数量增加,花色苷稳定性增强。乙酰化花色苷稳定性强于对香豆酰化花色苷。肠道微生物对葡萄酒花色苷降解的促进作用与花色苷结构有关。     

补充维生素D对非酒精性脂肪肝病患者肠道菌群的影响

为探索补充维生素D（VD）对于NAFLD患者肠道菌群的影响。本研究共纳入29例NAFLD患者,采用随机分组法分为对照组（只接受内科治疗,n=15）和VD组（在内科治疗的基础上,补充维生素D₂,n=14）。根据中国药典的剂量标准,对VD组NAFLD患者一次性给予60万国际单位VD₂,肌肉注射。30天后测定患者血清生化指标,采集患者粪便,进行16S rRNA测序分析,比较治疗前后肠道菌群在多样性、丰度的变化,以及肠道菌群与生化指标的相关性。研究结果表明：补充VD之后,NAFLD患者血清丙氨酸氨基转移酶（ALT）水平显著降低（P<0.001）,肠道菌群多样性无显著变化（P>0.05）,但毛螺菌科丰度显著降低（P<0.01）,丹毒丝菌科（P<0.01）、丹毒丝菌科未命名属（P<0.05）丰度显著升高;毛螺菌科相对丰度水平与血清甘油三酯（TG）（P<0.05）呈显著正相关,丹毒丝菌科（P<0.01）和丹毒丝菌科未命名属（P<0.05）与血清25（OH）D水平呈显著正相关,而与ALT、天门冬氨酸氨基转移酶（AST）呈显著负相关（ALT：P<0.000 1;AST：P<0.05）;补充VD能够显著降低血清ALT水平,对NAFLD患者肝损伤有一定改善作用;VD能显著降低患者肠道菌群毛螺菌科的丰度,显著提高丹毒丝菌科和丹毒丝菌科未命名属的丰度,进而降低血清TG、ALT和AST水平。     

Cholinesterases are down-expressed in human colorectal carcinoma

The aberrations of cholinesterase (ChE) genes and the variation of ChE activity in cancerous tissues prompted us to investigate the expression of ChEs in colorectal carcinoma. The study of 55 paired specimens of healthy (HG) and cancerous gut (CG) showed that acetylcholinesterase (AChE) activity fell by 32% and butyrylcholinesterase (BuChE) activity by 58% in CG. Abundant AChE-H, fewer AChE-T, and even fewer AChE-R and BuChE mRNAs were observed in HG, and their content was greatly diminished in CG. The high level of the AChE-H mRNA explains the abundance of AChE-H subunits in HG, which as glycosylphosphatidylinositol (GPI)-anchored amphiphilic AChE dimers (G₂^A) and monomers (G₁^A) account for 69% of AChE activity. The identification of AChE-T and BuChE mRNAs justifies the occurrence in gut of A₁₂, G₄^H and PRiMA-containing G₄^A AChE forms, besides G₄^H, G₄^A and G₁^H BuChE. The down-regulation of ChEs might contribute to gut carcinogenesis by increasing acetylcholine availability and overstimulating muscarinic receptors. Received 19 May 2006; received after revision 5 June 2006; accepted 5 July 2006