Coupling membranes as energy-transmitting cables. I. Filamentous mitochondria in fibroblasts and mitochondrial clusters in cardiomyocytes.
Coupling membranes as energy-transmitting cables. I. Filamentous mitochondria in fibroblasts and mitochondrial clusters in cardiomyocytes.
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DOI：
10.1083/jcb.107.2.481
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发表时间：
1988-08
期刊：
影响因子：
--
通讯作者：
Zorov DB
中科院分区：
文献类型：
--
作者：
Amchenkova AA;Bakeeva LE;Chentsov YS;Skulachev VP;Zorov DB
将线粒体视为细胞内能量传递质子电缆的假设在人成纤维细胞和大鼠心肌细胞中进行了验证，其中人成纤维细胞的线粒体又细又长，而大鼠的心肌细胞则表现出簇状组织。细胞中的线粒体被荧光穿透性阳离子乙基罗丹明特异地染色，该阳离子在线粒体基质中电泳性积累。用非常窄(小于或等于0.5微米)的激光照射40微米长的成纤维细胞线粒体丝，造成线粒体膜的局部损伤。这种处理被发现在整个细丝中引起乙基罗丹明荧光的猝灭。根据电子显微镜观察，激光处理后的纤维在激光照射后仍保持其连续性。其他线粒体细丝(其中一些定位在距离激光治疗的线粒体丝不到10微米的距离)仍然是荧光的。在线粒体细丝似乎连接成网络的细胞中，激光照射一根细丝会导致整个网络的荧光猝灭，而没有连接网络的小线粒体的荧光不受影响。研究发现，心肌细胞受到激光照射后，不仅线粒体的荧光猝灭，而且由许多线粒体组成的细胞器也会发生荧光猝灭。电子显微镜显示，簇内所有线粒体均由正态变为凝集态。研究还发现，簇中的线粒体通过特定的连接相互连接。如果线粒体没有与猝灭的簇形成连接，即使当线粒体定位在靠近发光的线粒体时，其荧光也不会减少。线粒体簇的大小可能长达50微米。该簇是由接触线粒体的分支链形成的，可定义为链霉菌线粒体。在心肌细胞中有几个线粒体簇，或者，猝灭的簇是连接细胞所有线粒体的超簇分解的结果。用微血管原位穿刺法也能显示单个线粒体的簇状组织。所获得的数据与线粒体连接是H+通透的想法是一致的，因此，在簇内，增量psi可以从一个线粒体传递到另一个线粒体。上述结果与线粒体细丝或网络代表一个统一的电子系统的假设是一致的。
An hypothesis considering mitochondria as intracellular power- transmitting protonic cables was tested in human fibroblasts where mitochondria are thin and long and in rat cardiomyocytes where they show cluster organization. Mitochondria in the cell were specifically stained with fluorescent-penetrating cation ethylrhodamine, which electrophoretically accumulates in the mitochondrial matrix. A 40- micron-long mitochondrial filament of fibroblast was illuminated by a very narrow (less than or equal to 0.5 micron) laser beam to induce local damage of the mitochondrial membranes. Such a treatment was found to induce quenching of the ethylrhodamine fluorescence in the entire filament. According to the electron microscope examination, the laser- treated filament retained its continuity after the laser illumination. Other mitochondrial filaments (some of which were localized at a distance less than 10 micron from the laser-treated one) remained fluorescent. In a cell where mitochondrial filaments seemed to be united in a network, laser illumination of one filament resulted in fluorescence quenching in the whole network, whereas fluorescence of small mitochondria not connected with the network was unaffected. The illumination of cardiomyocyte was found to result in the fluorescence quenching not only in a laser-illuminated mitochondrion but also in a large cluster of organelles composed of many mitochondria. Electron microscopy showed that all the mitochondria in the cluster change from the orthodox to the condensed state. It was also found that mitochondria in the cluster are connected to one another with specific junctions. If a mitochondrion did not form junctions with a quenched cluster, its fluorescence was not decreased even when this mitochondrion was localized close to an illuminated one. The size of the mitochondrial cluster may be as long as 50 micron. The cluster is formed by branched chains of contacting mitochondria, which may be defined as Streptio mitochondriale. In the cardiomyocyte there are several mitochondrial clusters or, alternatively, the quenched cluster is a result of decomposition of a supercluster uniting all the mitochondria of the cell. Cluster organization of mitochondria could also be revealed when a single mitochondrion was punctured in situ with a microcapillary. The obtained data are in agreement with the idea that mitochondrial junctions are H+ permeable so that, within the cluster, delta psi may be transmitted from one mitochondrion to another. The above results are consistent with the assumption that mitochondrial filaments or networks represent a united electrical system.(ABSTRACT TRUNCATED AT 400 WORDS)