细菌质粒包裹于磷脂囊泡中：基因转移的潜力

Fraley R T, Fornari C S, Kaplan S

Proc Natl Acad Sci U S A. 1979 Jul;76(7):3348-52. doi: 10.1073/pnas.76.7.3348.

Entrapment of pBR322 DNA within liposomes was demonstrated by (i) its comigration with liposomes on Sepharose 4B columns, (ii) resistance of its biological activity to DNase digestion, and (iii) identification of plasmid DNA on agarose gels after lipid extraction. The biological activity of the liposome-entrapped plasmid was determined by transformation assays. The incubation of intact liposomes, containing entrapped pBR322, with competent Escherichia coli cells in the standard transformation mixture resulted in the appearance of tetracycline-resistant colonies at a frequency of 1% of the control frequency. Importantly, this frequency was unaffected by the addition of DNase to the incubation mixture, whereas transformation by free pBR322 DNA was totally eliminated after treatment with DNase.

通过以下方式证明了pBR322 DNA被包裹在脂质体内：（i）它与脂质体在琼脂糖4B柱上共同迁移；（ii）其生物活性对DNA酶消化具有抗性；（iii）脂质提取后在琼脂糖凝胶上鉴定出质粒DNA。通过转化试验测定了脂质体包裹的质粒的生物活性。在标准转化混合物中，将含有包裹的pBR322的完整脂质体与感受态大肠杆菌细胞一起孵育，结果出现了四环素抗性菌落，其频率为对照频率的1%。重要的是，该频率不受向孵育混合物中添加DNA酶的影响，而游离pBR322 DNA在经DNA酶处理后完全丧失转化能力。