中文摘要：

目的研究HMGN2对大肠埃希氏菌TA系统作用。方法用5％高氯酸萃取兔胸腺组织，通过反相高效液相色谱进一步分离纯化蛋白，用Tricine-SDS-PAGE、AU-PAGE和Dot-blot进行鉴定。采用凝胶迁移阻滞试验（EMSA）检测HMGN2对大肠埃希氏菌TA系统的结合作用；平板菌落记数法检测TA系统激活或非激活条件下，菌体过表达重组HMGN2和对照组对细菌存活百分率的影响。结果HMGN2可阻滞mazEF基因的泳动速率，且随HMGN2浓度增加，阻滞作用增强。利福平激活TA系统，菌体过表达重组HMGN2后，与对照组比较细菌存活量减少约30％，有统计学差异。而头孢哌酮不能激活TA系统，过表达重组HMGN2组和空质粒组CFU％分别为70．2％、68．9％，两者无明显差异。结论HMGN2可加强mazEF系统介导的细菌程序性死亡；HMGN2对TA系统的作用也可能是其抗大肠埃希氏菌作用的机制之一。

英文摘要：

Objective To study the effect of HMGN2 on toxin-antitoxin （TA） gene system in E. coll. Methods The thymus gland tissue of rabbit was extracted with 5 0/60 perchlorate, then HMGN2 was purified by reversed phase high performance liquid chromatography （RP-HPLC） and identified by Tricine-SDS-PAGE , AU-PAGE and Dot blotting. The binding activity of HMGN2 to TA gene was detected by the electrophoretic mobility shift assay （EMSA）. Under the TA system activated or non-activated, the number of colony forming units （CFU） was calculated by agar plate colony counting and compared between E. coli overexpressed HMGN2 group and control group. Results The electrophoresis speed of the mazEF could be blocked by HMGN2, and the action was enhanced with the concentration increasing of the HMGN2 molecules. The TA system was activated with rifampicin. The number of CFU of overexpressed HMGN2 group were significantly less than control group 30% （P〈0.01）. Cefoperazone could not activate the TA system, the number of CFU of both group was 70. 20% and 68. 9%, respectively. There was no statistic difference （P〉0. 05）. Conclusion HMGN2 could enhance the bacteria programmed cell death mediated by the mazEF system. It might be one of the mechanisms of HMGN2 against E. coll.