【摘要】 碱变性和羟基磷灰石柱层析分离纯化大肠杆菌重组质粒ＰＷＪ１４０ＤＮＡ，经ＰＳＴＩ完全酶解，琼脂糖凝胶电泳分离，电洗脱回收５．９ｋｂ片段，经化学修饰转氨基作用后制成ＬＴ基因的生物素探针，斑点印迹杂交试验表明，生物素ＬＴ基因探针灵敏性高，可检测到ｐｇ水平，与标准的ＥＴＥＣ（ＬＴ＋）杂交阳性，与非ＥＴＥＣ的大肠杆菌、沙门氏菌等无杂交反应。２０份不同来源的样品试验结果表明，ＬＴ探针可用于检测猪、牛、人、鸡及食品来源的毒素源性大肠杆菌。更多还原

【Abstract】 The recombinarnt plasmid PWJ140 was extracted and purified by the alkaline lysisand HA,A519kd,PSTI fregment of PWJ149 was isotaled with agarose gel electroelution and labelled with biotiny-e-amino caproic acid-N-hydroxysueeinimice ester by the transamination of sodium bisulfite and ethynedamine.The bio- DNA probe was highly specific for ETEC,E.coli dot blot hybridization assay. As little as 10pg of target DNA was detected bythe bio- DNA probe,20 samples from different origin were deteeted.更多还原