畜牧兽医学报 ›› 2014, Vol. 45 ›› Issue (8): 1336-1341.doi: 10.11843/j.issn.0366-6964.2014.08.019

• 基础兽医 • 上一篇    下一篇

牛源产Ⅱ型不耐热肠毒素大肠杆菌的分离鉴定及重组毒素制备

袁超文,刘文鑫,关玮琨,孟相秋,唐杰,李星月,赵志腾,师东方*   

  1. (东北农业大学动物医学学院,哈尔滨 150030)
  • 收稿日期:2014-01-09 出版日期:2014-08-23 发布日期:2014-08-23
  • 通讯作者: 师东方,教授,博导,主要从事动物传染病诊断与防治研究,E-mail:shidf@neau.edu.cn
  • 作者简介:袁超文(1989-),男,黑龙江哈尔滨人,硕士生,主要从事动物传染病诊断与防治研究,E-mail:yuanchaowen520@163.com,Tel:0451-55190096
  • 基金资助:

    国家科技支撑计划项目(2012BAD12B03;2012BAD12B05);黑龙江省科技计划项目(GC12B303)

Isolation of Type Ⅱ Heat-labile Enterotoxin-producing Escherichia coli and Preparation of the Recombinant Toxin

YUAN Chao-wen,LIU Wen-xin,GUAN Wei-kun,MENG Xiang-qiu,TANG Jie,LI Xing-yue,ZHAO Zhi-teng,SHI Dong-fang*   

  1. (Department of Preventive Veterinary Medicine,College of Veterinary Medicine,Northeast Agricultural University,Harbin 150030,China)
  • Received:2014-01-09 Online:2014-08-23 Published:2014-08-23

摘要:

产Ⅱ型不耐热肠毒素(LT-Ⅱ)大肠杆菌是一类能引起严重腹泻的人畜共患肠道致病菌。为了解LT-Ⅱ在牛源腹泻性大肠杆菌中的流行情况,本研究对2010—2012年间分离的138株大肠杆菌进行了LT-Ⅱ毒素基因的检测,对分离到的10株LT-Ⅱ阳性大肠杆菌进行了测序及分析。进一步将LT-Ⅱc1毒素基因双顺反子的ORF克隆入pET30a表达载体、转化Rossatta感受态并诱导表达重组LT-Ⅱc1毒素,经Y-1小鼠肾上腺皮质细胞对重组毒素进行了初步的毒性验证。结果显示,所分离的10株LT-Ⅱ阳性大肠杆菌中,有8株表达LT-Ⅱc1毒素,1株表达LT-Ⅱc4毒素,1株表达LT-Ⅱc6毒素。SDS-PAGE和Western Blot结果表明成功地制备出LT-Ⅱc1重组毒素,该重组毒素可以使Y-1小鼠肾上腺皮质细胞发生明显的病变,其细胞最小致死量为17.8 pg。本研究为中国国内首次分离到牛源产LT-Ⅱ型不耐热肠毒素大肠杆菌,为深入研究LT-Ⅱ毒素奠定了基础。

Abstract:

Type Ⅱ heat-labile enterotoxin (LT-Ⅱ)-producing Escherichia coli is a common zoonotic pathogenic agent responsible for diarrhea.In order to improve the understanding of the epidemiological situation of LT-Ⅱ toxin in cattle,a total of 138 E.coli isolates from 2010 to 2012 were detected for LT-Ⅱ gene by PCR,and ten of these were sequenced.The polycistron ORF of LT-Ⅱc1 was cloned into the pET30a expression vector,translated into Rossatta competent cells,and induced for expressing the recombinant LT-Ⅱ toxin.The toxicity of the recombinant LT-Ⅱ toxin was preliminary tested by mouse Y1 adrenal cells.The results showed that eight samples were LT-Ⅱc1 producing E.coli,one was LT-Ⅱc4 producing E.coli and one was LT-Ⅱc6 producing E.coli from ten LT-Ⅱ positive.The results of SDS-PAGE and Western Blot showed that recombinant LT-Ⅱc1 toxin was prepared successfully,and the recombinant toxin had induced the apparent cytopathic effect for mouse Y1 adrenal cells,with the minimum lethal dose of 17.8 pg.The results presented here demonstrate that we isolated the LT-Ⅱ producing E.coli for the first time in China,and lay a preliminary foundation for further study of the LT-Ⅱ toxin.

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