荧光原位杂交技术分析人结肠菌群方法研究

建立荧光原位杂交技术分析人体内结肠菌群的方法。取受试者新鲜粪便 ,选用 5种特异性的 16SrRNA寡核苷酸探针 ,检测粪便样本收集后的保存时间、温度 ,离心条件及样本固定液存放时间对杂交计数结果的影响。结果建立最佳实验条件为 :粪便样本收集后应尽快在 4℃下保存 ,放置时间不要超过 12小时即作处理 ;样本的适宜离心条件为 70 0g 2分钟 ;样本用多聚甲醛固定后在 - 80℃下存放时间不要超过 5个月。该方法具有较好的稳定性 ,可以有效地检出个体之间结肠菌群的差异。     

Structure-activity relationship in the gastric cytoprotective effect of several sesquiterpene lactones.

The structural requirements for the gastric cytoprotective activity of several sesquiterpene lactones are reported. A theoretical-experimental study on the potentially active centers is carried out. The biological evaluation of reduced analogues and the simulation of the molecular interactions between these compounds and an endogenous cysteine residue suggest that the presence of a non sterically hindered Michael acceptor seems to be an essential structural requirement for the cytoprotective activity in this family of compounds. This observation suggests that cytoprotection is mediated through a Michael reaction between the sulfhydryl-containing peptides of the mucosa and Michael acceptors present in the molecules under study. This mechanism of action is in addition to and distinct from the one proposed in our previous paper, namely, that these sesquiterpenes stimulate endogenous synthesis of prostaglandins.