United States Department of Agriculture, MQRD, University of California, Los Angeles, California.
Plant Physiol. 1968 Dec;43(12):2001-22. doi: 10.1104/pp.43.12.2001.
Sweetpotato mitochondria, that showed respiratory control, were studied with respect to ultrastructure. If fixed in media containing sucrose at 0.4 M, the cristae were dilated and the matrix was highly condensed. A more orthodox ultrastructural form was observed when the mitochondria were fixed in a medium containing sucrose at 0.25 M, i.e., the matrix was more expanded, the cristae were less dilated, and peripherally, the inner membrane element lay adjacent to the outer membrane element. These results are discussed in terms of a sucrose-accessible space (space between outer and inner membrane elements including intracristal space), and a space relatively inaccessible to sucrose (matrix). Ultrastructural shifts were not observed with change in metabolic steady state of the mitochondria. High resolution electron micrographs showed that the ultrastructure of sweetpotato mitochondria is very similar to that of animal mitochondria.Purity and homogeneity of mitochondrial fractions were followed both by phase-contrast and electron microscopy. Preparations from sweetpotato, using older methods, were relatively homogeneous with respect to particle type and size, whereas avocado preparations contained a high proportion of chloroplasts and cellular debris. A method of purification involving sucrose-density-gradient centrifugation was developed. Purified mitochondria exhibited respiratory control and appeared similar to unpurified mitochondria under the electron microscope.
对具有呼吸控制能力的甘薯线粒体进行了超微结构研究。如果将其固定在含有 0.4M 蔗糖的介质中，嵴会扩张，基质高度浓缩。当将线粒体固定在含有 0.25M 蔗糖的介质中时，会观察到更正统的超微结构形式，即基质更加扩张，嵴扩张程度较低，并且在内膜元件的外周与外膜元件相邻。这些结果是根据蔗糖可及空间（外膜元件和内膜元件之间的空间，包括嵴内空间）和蔗糖相对不可及的空间（基质）来讨论的。线粒体代谢稳态的变化不会引起超微结构的变化。高分辨率电子显微镜显示，甘薯线粒体的超微结构与动物线粒体非常相似。通过相差和电子显微镜观察到线粒体部分的纯度和均一性。使用较旧方法从甘薯中制备的制剂在颗粒类型和大小方面相对均一，而鳄梨制剂则含有大量的叶绿体和细胞碎片。开发了一种涉及蔗糖密度梯度离心的纯化方法。纯化的线粒体表现出呼吸控制，并且在电子显微镜下与未纯化的线粒体相似。
