Danilevich V N, Kadykov V A, Grishin E V
Bioorg Khim. 2010 May-Jun;36(3):375-86. doi: 10.1134/s106816201003009x.
It has been previously found that in a PCR with yeast genomic DNA as a template, microparticles of condensed DNA are formed in the presence of KlenTaq polymerase. In the present work, the study of these microparticles was continued using electron microscopy. It was shown that along with standard electron-dense microspheres, microspheres of a low electron density with a few thorns or without any thorns are formed. Various types of nanoparticles were detected in the samples: nanowires, dot-like electron-absorbing particles (nanodots), and compact nanoparticles (nanoscales) of different shape and size. It was found that increasing the number of PCR cycles above the optimum leads to an abrupt rise in the amount of nanoparticles in the PCR mixture. Suspensions of microparticles after quick (5 min) heating at 94 degrees C were examined. The partial melting of the microspheres in the heated samples was established: they lost part of the DNA and decreased in size; simultaneously, abundant clusters of nanowires appeared. The effect of nuclease S1 on the DNA of microspheres was studied. The molecular mechanisms of the formation of micro- and nanoparticles are discussed.
先前已经发现，在以酵母基因组DNA为模板的聚合酶链反应（PCR）中，在KlenTaq聚合酶存在的情况下会形成浓缩DNA的微粒。在当前工作中，利用电子显微镜继续对这些微粒进行研究。结果表明，除了标准的电子致密微球外，还会形成具有少量刺或无刺的低电子密度微球。在样品中检测到了各种类型的纳米颗粒：纳米线、点状电子吸收颗粒（纳米点）以及不同形状和大小的致密纳米颗粒（纳米鳞片）。发现将PCR循环次数增加到最佳次数以上会导致PCR混合物中纳米颗粒的数量急剧增加。对在94摄氏度下快速（5分钟）加热后的微粒悬浮液进行了检查。确定了加热样品中微球的部分熔化：它们失去了部分DNA并尺寸减小；同时，出现了大量纳米线簇。研究了核酸酶S1对微球DNA的作用。讨论了微米和纳米颗粒形成的分子机制。
