Fath K R, Lasek R J
Bio-architectonics Center Medical School, Case Western Reserve University, Cleveland, Ohio 44106.
J Cell Biol. 1988 Aug;107(2):613-21. doi: 10.1083/jcb.107.2.613.
The distribution and length of actin microfilaments (MF) was determined in axoplasm extruded from the giant axons of the squid (Loligo pealeii). Extruded axoplasm that was separated from the axonal cortex contains approximately 92% of the total axonal actin, and 60% of this actin is polymerized (Morris, J., and R. Lasek. 1984. J. Cell Biol. 98:2064-2076). Localization of MF with rhodamine-phalloidin indicated that the MF were organized in fine columns oriented longitudinally within the axoplasm. In the electron microscope, MF were surrounded by a dense matrix and they were associated with the microtubule domains of the axoplasm. The surrounding matrix tended to obscure the MF which may explain why MF have rarely been recognized before in the inner regions of the axon. The axoplasmic MF are relatively short (number average length of 0.55 micron). Length measurements of MF prepared either in the presence or absence of the actin-filament stabilizing drug phalloidin indicate that axoplasm contains two populations of MF: stable MF (number average length of 0.79 micron) and metastable MF (number average length of 0.41 micron). Although individual axonal MF are much shorter than axonal microtubules, the combined length of the total MF is twice that of the total microtubules. Apparently, these numerous short MF have an important structural role in the architecture of the inner axonal cytoskeleton.
对从鱿鱼（加州双柔鱼）巨轴突挤出的轴浆中肌动蛋白微丝（MF）的分布和长度进行了测定。与轴突皮质分离的挤出轴浆含有约92%的轴突总肌动蛋白，其中60%的肌动蛋白已聚合（莫里斯，J.，和R.拉塞克。1984年。《细胞生物学杂志》98:2064 - 2076）。用罗丹明 - 鬼笔环肽定位MF表明，MF在轴浆内纵向排列成细柱状。在电子显微镜下，MF被致密基质包围，并且它们与轴浆的微管区域相关。周围的基质往往会掩盖MF，这可能解释了为什么以前在轴突内部区域很少识别到MF。轴浆中的MF相对较短（数均长度为0.55微米）。在存在或不存在肌动蛋白丝稳定药物鬼笔环肽情况下制备的MF的长度测量表明，轴浆中含有两种MF群体：稳定MF（数均长度为0.79微米）和亚稳定MF（数均长度为0.41微米）。虽然单个轴突MF比轴突微管短得多，但总MF的总长度是总微管的两倍。显然，这些众多的短MF在轴突内部细胞骨架的结构中具有重要的结构作用。
