Chaussee M S, Hill S A
Laboratory of Microbial Structure and Function, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA
J Bacteriol. 1998 Oct;180(19):5117-22. doi: 10.1128/JB.180.19.5117-5122.1998.
Neisseria gonorrhoeae is naturally competent for DNA transformation. In contrast to other natural prokaryotic DNA transformation systems, single-stranded donor DNA (ssDNA) has not previously been detected during transformation of N. gonorrhoeae. We have reassessed the physical nature of gonococcal transforming DNA by using a sensitive nondenaturing native blotting technique that detects ssDNA. Consistent with previous analyses, we found that the majority of donor DNA remained in the double-stranded form, and only plasmid DNAs that carried the genus-specific DNA uptake sequence were sequestered in a DNase I-resistant state. However, when the DNA was examined under native conditions, S1 nuclease-sensitive ssDNA was identified in all strains tested except for those bacteria that carried the dud-1 mutation. Surprisingly, ssDNA was also found during transformation of N. gonorrhoeae comA mutants, which suggested that ssDNA was initially formed within the periplasm.
淋病奈瑟菌具有天然的DNA转化能力。与其他天然原核生物DNA转化系统不同，在淋病奈瑟菌转化过程中，此前尚未检测到单链供体DNA（ssDNA）。我们通过使用一种能检测ssDNA的灵敏非变性原位印迹技术，重新评估了淋球菌转化DNA的物理性质。与之前的分析一致，我们发现大多数供体DNA仍保持双链形式，只有携带属特异性DNA摄取序列的质粒DNA以抗DNase I的状态被隔离。然而，当在天然条件下检查DNA时，除了携带dud - 1突变的细菌外，在所有测试菌株中都鉴定出了对S1核酸酶敏感的ssDNA。令人惊讶的是，在淋病奈瑟菌comA突变体的转化过程中也发现了ssDNA，这表明ssDNA最初是在周质中形成的。
