中文摘要：

目的：获得重组抗茵肽S-thanatin（Ts）在大肠杆菌的可溶性表达及分离纯化方法，通过不同方法鉴定Ts的最低抑茵浓度（MIC），揭示不同方法对结果的影响。方法：利用基因重组手段构建表达质粒pET32a-Ts，转化大肠杆菌BL21（DE3），可溶性表达Ts融合蛋白，利用镍柱亲和层析纯化出融合蛋白，透析以后经凝血酶酶切，再通过葡聚糖凝胶G-50纯化除去融合伴侣TRX，最后冻干精制得到Ts冻干粉。利用玻璃管的常量肉汤稀释法、聚苯乙烯和聚丙烯96孔板的微量肉汤稀释法和MH琼脂打孔法测定阳离子肽Ts的抑菌活性。结果：Ts在大肠杆菌中成功可溶性表达并获得85％以上纯度的目的蛋白。不同测定方法显示，Ts对同一菌株具有不同的MIC，以常量肉汤稀释法和聚丙烯96孔板的微量肉汤稀释法测定的多肽抑菌活性效果最

英文摘要：

Objective： To study the expression and purification of antimicrobial peptide S-thanatin in Escherichia coli and the effecs of different MIC identification methods on it. Methods ： A recombinant plasmid pET32a-Ts cod- ing for fusion protein in Escherichia coli was constructed by recombinant gene technique. The fusion protein was pu- rified through Nickel- affinity chromatography column, then TRX was cut off by thrombin after dialysis, purified by Sephadex G-50 chromatography, and finally freeze-dried. Constant broth dilution method, microdilution method and punching method were used to observe the MIC of S-thanatin. Results： S-thanatin was successfully expressed in E. coli, and the final purity was higher than 85%. Different identification methods of MIC about Ts showed dif- ferent results, the constant broth dilution method and PP 96 pores plate gave the best effect. Conclusion： Ts is highly expressed in engineering strain BL21 （DE3）, and the purified protein has a high biological activity. MIC of PP 96 pores plate and constant broth dilution method give the accurate result. The antibacterial activity is influ- enced by the experimental material.