中文摘要：

目的克隆伤寒沙门菌菌毛操纵子stg基因,在大肠埃希菌中表达;了解伤寒沙门菌stg与人上皮细胞的相互作用。方法根据大肠埃希菌保守基因序列设计引物,克隆stg成熟肽编码序列,连接到原核表达载体pET32a,构建重组表达质粒,转化至大肠埃希菌BL21（DE3）中并观察与上皮细胞的粘附特性。结果成功克隆stg基因全长核苷酸序列,构建了pET32a/stg原核表达重组质粒。pET32a/stg重组质粒转化大肠埃希菌能较多出现在上皮细胞表面。结论成功克隆并表达了伤寒沙门菌菌毛操纵子stg基因,stg基因能促进沙门菌对上皮细胞的粘附,为进一步了解伤寒沙门菌菌毛操纵子stg的特性与功能奠定了基础。

英文摘要：

Objective To clone and express the the gene of the stg fimbrial operon from Salmonella enterica serovar Typhi.Methods Primers were designed based on the conserved sequences of E.coli.The nucleotide sequence encoding mature Stg of Salmonella enterica serovar Typhi was cloned and ligated into pET32a to construct a recombinant pET32a/stg plasmid.The recombinant Stg was expressed in E.coli BL21（DE3） and its adherence to human epithelial cells was observed.Results The stg full-length nucleotide sequence containing an open reading frame of 5 kb that encoded a protein consisting of 1 660 amino acids.The deduced stg sequence contained the characteristic motifs of the stg family.The mature stg was successfully ligated into the pET32a plasmid and expressed in E.coli BL21（DE3）.E.coli BL21（DE3） with the recombinant pET32a/stg plasmid was readily evident around epithelial cells.Conclusion The Stg fimbrial operon from the Salmonella enterica serovar Typhi was cloned and successfully expressed.The stg gene may help bacteria to enter human cells.This work has provided a basis for understanding the characteristics and functions of the stg fimbrial operon from Salmonella enterica serovar Typhi.