Bridgelike interconnections between thick filaments in stretched skeletal muscle fibers observed by the freeze-fracture method.
Bridgelike interconnections between thick filaments in stretched skeletal muscle fibers observed by the freeze-fracture method.
复制标题
通过冷冻断裂法观察到拉伸骨骼肌纤维中粗丝之间的桥状互连。
DOI：
10.1083/jcb.102.3.1093
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Pollack,GH
中科院分区：
文献类型：
--
作者：
Suzuki,S;Pollack,GH
采用冷冻断裂、深刻蚀、旋转阴影技术对蛙半腱肌的超微结构进行了研究。在用液体丙烷快速冷冻之前，机械剥皮的纤维被拉伸以减少或消除粗丝和细丝的重叠。在松弛的、收缩的和僵硬的纤维中，在非重叠区的相邻粗纤维之间观察到大量桥状连接，这与在M区观察到的不同。它们的半长和直径与已知的跨桥(或肌球蛋白S-1)的尺寸大致相符。因此，可以通过结合从相邻粗丝突出的两个相对的交叉桥来形成互连。冷冻前用0.5%戊二醛固定5~10min，有效地保存了这些结构。结果表明，这些相互连接是真正的结构，通常出现在拉伸的肌肉纤维中。它们可能起到稳定粗纤维晶格的作用，也可能在收缩过程中起作用。
The ultrastructure of frog semitendinosus muscle was explored using the freeze-fracture, deep-etch, rotary-shadowing technique. Mechanically skinned fibers were stretched to decrease or eliminate the overlap of thick and thin filaments before rapid freezing with liquid propane. In relaxed, contracting, and rigor fibers, a significant number of bridgelike interconnections, distinct from those observed in the M-region, were observed between adjacent thick filaments in the non-overlap region. Their half-length and diameter corresponded approximately to the known dimensions of the cross-bridge (or myosin S-1). The interconnection may thus be formed by the binding of two apposed cross-bridges projecting from adjacent thick filaments. Fixation with 0.5% glutaraldehyde for 5-10 min before freezing effectively preserved these structures. The results indicate that the interconnections are genuine structures that appear commonly in stretched muscle fibers. They may play a role in stabilizing the thick filament lattice, and possibly in the contractile process.