It is known that mitochondrial population of living organisms is heterogeneous. Using the density gradient of Percoll or sucrose, we obtained and characterized two distinct mitochondrial subfractions (named “light” and “heavy” according to their sedimentation) from three plant species (Brassica rapa, Zea mays, and Arabidopsis thaliana). Electron microscopy showed that mitochondria of a light subfraction have a poorly developed cristae structure. The respiratory control of these mitochondria was reduced; however the degree of their outer membrane integrity remained high. These data suggest that mitochondrial subfractions purified in the density gradient differ in their maturity. We carried out DNA import assays to study the ability of these two subfractions for DNA transport. We have shown that the mitochondria of light subfraction in all three plant species uptakes DNA more efficiently than the mitochondria of heavy subfraction. In addition, import of DNA with different sizes into the light and heavy mitochondrial subfractions has different sensitivity to specific inhibitors of the voltage-dependent anion channel and adenine nucleotide translocase, proteins playing a central role in DNA transport across the mitochondrial membrane. The obtained results suggest that DNA import depends on organization of the transport system in the double mitochondrial membrane influenced by the maturity of the mitochondria.

中文翻译：

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植物线粒体亚型具有不同的DNA导入能力

众所周知，生物的线粒体种群是异质的。使用Percoll或蔗糖的密度梯度，我们从三种植物物种（芸苔属rapa，Zea mays和Arabidopsis thaliana）获得并表征了两个不同的线粒体亚组分（根据它们的沉积分别命名为“轻”和“重”））。电子显微镜显示，轻度亚组分的线粒体的cr结构发育不良。这些线粒体的呼吸控制降低；然而，它们的外膜完整性仍然很高。这些数据表明，以密度梯度纯化的线粒体亚组分的成熟度不同。我们进行了DNA导入检测，以研究这两个亚级的DNA转运能力。我们已经显示，在所有三种植物物种中，轻亚组分的线粒体比重亚组分的线粒体更有效地吸收DNA。此外，将不同大小的DNA导入到轻和重的线粒体亚组分中，对电压依赖性阴离子通道和腺嘌呤核苷酸转位酶的特定抑制剂的敏感性不同，蛋白质在跨线粒体膜的DNA转运中起重要作用。获得的结果表明，DNA的导入取决于线粒体成熟程度影响的双线粒体膜运输系统的组织。