抗H：z66抗体诱导z66~＋伤寒沙门菌鞭毛相变换特点的探讨

目的探讨抗H∶z66抗体诱导z66＋伤寒沙门菌鞭毛相变换的特点。方法利用含抗H∶z66抗体的半固体培养基诱导z66＋伤寒沙门菌鞭毛发生相变换,通过提取z66＋伤寒沙门菌和其相变株的线性质粒,利用脉冲场凝胶电泳和核酸内切酶分析比较z66＋伤寒沙门菌鞭毛相变换前后线性质粒的结构,最后通过测定相变株的线性质粒全序列和Southern blot进一步揭示抗H∶z66抗体诱导z66＋伤寒沙门菌鞭毛相变换的特点。结果 z66＋伤寒沙门菌在抗H∶z66抗体的诱导下成功发生了鞭毛的单向相变换;这种单向相变换是由于伤寒沙门菌在抗体诱导下线性质粒缺失了含fljBA的2.6 kb末端区域所致,同时首次发现在鞭毛相变换后线性质粒结构反而变大,提示线性质粒可能形成了非共价结合的二聚体。结论该研究揭示了z66＋伤寒沙门菌鞭毛的相变换特点,为更深入地研究z66＋伤寒沙门菌奠定了基础。

Study on the Characteristic of Flagellar Phase Variation of H:z66 Positive Salmonella Enterica Serovar Typhi with the Anti-H:z66 Antibody

Objective To study the characteristic of flagellar phase variation of H∶z66 positive Salmonella enterica serovar Typhi induced by the anti-H∶z66 antibody.Methods The H∶z66 positive Salmonella enterica serovar Typhi GIFU10007 was induced by the anti-H∶z66 antibodies on semi-solid LB plate.The linear plasmids of wild strain GIFU10007 and its derivative j＋ strain inducing with anti-H∶z66 antibodies were extracted,and then analyzed by pulse field gel electrophoresis（PFGE） and digested by restriction enzyme.The linear plasmid of derivative j＋ strain was sequenced by shot-gun method.Results The H∶z66 positive Salmonella enterica serovar Typhi GIFU10007 were shown to undergo flagellar phase variation from z66 to j antigen after induction by the anti-H∶z66 antibody.This unidirectional flagellar phase variation was caused by deletion of a 2.6 kb terminal region containing the majority of the fljBA gene cluster.This study first found that the linear plasmid of derivative j＋ strain showed larger than that of wild strain GIFU10007 in the PFGE experiment,suggesting the formation of a non-covalent dimer.The sequence of linear plasmid of derivative j＋ strain is consistent with other reports.Conclusion This study demonstrates the characteristic of flagellar phase variation of H∶z66 positive Salmonella enterica serovar Typhi and is a foundation to study deeply H∶z66 positive Salmonella enterica serover Typhi.