Morris G J, Coulson G E, Leeson E A
J Cell Sci. 1985 Jun;76:145-53. doi: 10.1242/jcs.76.1.145.
The effects of various stresses on mitochondrial activity and structure within the unicellular green alga Chlamydomonas reinhardii were investigated using the fluorescent probe rhodamine 123. Within control cells, treatment with rhodamine 123 stained an intense fluorescent network, which was considered to be mitochondrial from the similarity in structure to models of mitochondria reconstructed from serial-section electron microscopy, and because this pattern of staining was abolished following the addition of metabolic inhibitors. Following osmotic shrinkage and rehydration, fragmentation of the mitochondrial network was observed within potentially viable cells. This was reversible within 1 h of resuspension in isotonic medium. Exposure of cells to hypertonic solutions of rapidly permeating compounds did not induce similar structural alterations. These changes in the mitochondria were confirmed by thin-section electron microscopy. In the presence of higher osmolalities of non-permeating compounds, which induce a greater loss of viability, rhodamine 123 stained cells uniformly. Following the osmotic stresses induced by slow rates of freezing and subsequent thawing no fragmentation in mitochondrial staining was observed. These findings demonstrate that shrinkage and rehydration may induce alterations to the structure and function of organelles and may be factors in determining cellular viability following osmotic stress.
使用荧光探针罗丹明123研究了各种应激对单细胞绿藻莱茵衣藻线粒体内活性和结构的影响。在对照细胞中，用罗丹明123处理后，染出一个强烈的荧光网络，从结构与通过连续切片电子显微镜重建的线粒体模型的相似性来看，该网络被认为是线粒体，并且由于添加代谢抑制剂后这种染色模式消失。在渗透收缩和再水化后，在可能存活的细胞内观察到线粒体网络的碎片化。在等渗培养基中重悬1小时内这是可逆的。将细胞暴露于快速渗透化合物的高渗溶液中不会诱导类似的结构改变。线粒体的这些变化通过超薄切片电子显微镜得到证实。在存在诱导更大活力丧失的非渗透化合物的更高渗透压时，罗丹明123均匀地染细胞。在由缓慢冷冻速率和随后解冻诱导的渗透应激后，未观察到线粒体染色的碎片化。这些发现表明，收缩和再水化可能诱导细胞器结构和功能的改变，并且可能是决定渗透应激后细胞活力的因素。
