Morrison D A, Guild W R
J Bacteriol. 1973 Sep;115(3):1055-62. doi: 10.1128/jb.115.3.1055-1062.1973.
We exposed competent cells of Diplococcus pneumoniae to high-molecular-weight donor deoxyribonucleate (DNA) and examined the state of the DNA bound to them in forms sensitive to deoxyribonuclease I. The portion elutable with 5 M guanidine hydrochloride was shown to be native, of much lower molecular weight (4 x 10(6) to 5 x 10(6)) than the donor, and as active in further transformation as sheared DNA of the same size. The portion resistant to release by guanidine hydrochloride was also shown to be native and active in transformation. These results, along with previous ones, imply that the breaks produced outside the cell are not at genetically specific sites. Furthermore, it was found that entry past the cell barrier to deoxyribonuclease could occur at 0 C by a process sensitive to ethylenediaminetetraacetate.
我们将肺炎双球菌感受态细胞暴露于高分子量的供体脱氧核糖核酸(DNA)中,并以对脱氧核糖核酸酶I敏感的形式检查与之结合的DNA的状态。用5M盐酸胍可洗脱的部分显示为天然的,分子量比供体低得多(4×10⁶至5×10⁶),并且在进一步转化中与相同大小的剪切DNA一样活跃。对盐酸胍释放有抗性的部分也显示为天然的且在转化中具有活性。这些结果与先前的结果一起表明,在细胞外产生的断裂并非发生在基因特异性位点。此外,还发现脱氧核糖核酸酶在0℃时可通过对乙二胺四乙酸敏感的过程穿过细胞屏障进入细胞。