Contractile connective tissue in crinoids
Contractile connective tissue in crinoids
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DOI：
10.2307/1543055
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发表时间：
1996-08-01
影响因子：
1.6
通讯作者：
Motokawa, T
中科院分区：
文献类型：
--
作者：
Birenheide, R;Motokawa, T
动物的活跃运动通常归因于细胞蛋白质引擎，例如肌肉细胞的肌动蛋白-肌球蛋白系统。在这里，我们报告了细胞外收缩结缔组织的第一个证据，这是我们在海百合和羽毛星（棘皮目，海百合目）中发现的。这些海洋动物的手臂肌肉不受其他肌肉的拮抗，而是由散布着神经元样细胞过程的细胞外原纤维组成的韧带所拮抗。缺乏可收缩细胞，但这些手臂韧带在受到刺激时主动收缩。即使在刺激停止后，韧带仍处于收缩状态。所产生的应力低于典型骨骼肌。来自完全没有肌肉的海百合的额外数据证实了韧带结缔组织是可收缩的假设。
Active movements in animals are usually attributed to cellular protein engines, e.g., the actin-myosin system of muscle cells. Here we report the first evidence of an extracellular contractile connective tissue, which we have found in sea lilies and feather stars (Echinodermata, Crinoida). These marine animals have arm muscles that ave antagonized not by other muscles, but by ligaments consisting of extracellular fibrils interspersed with neuron-like cell processes. Contractile cells are lacking, yet these arm ligaments actively contracted upon stimulation. The ligaments stayed in a contracted condition even after the stimulus had stopped. The stresses generated were lower than those of typical skeletal muscles. Additional data from crinoid cirri, which lack muscles entirely, corroborate the hypothesis that the connective tissue of the ligaments is contractile.