Burke R D
Cell Tissue Res. 1985;239(3):589-97. doi: 10.1007/BF00219237.
During the first 15 to 20 min of metamorphosis the larval arms are retracted and resorbed into the aboral surface of the juvenile. Arms excised from metamorphosing larvae will undergo a sequence of contraction and histolysis that is identical to that occurring in intact larvae. Prior to and during metamorphosis, epidermal cells contain bundles of 5 to 7-nm microfilaments in arrays radiating apically from the base of the cells. Sparse microfilaments also occur near the plasmalemma of epidermal cells and some mesenchymal cells in larvae fixed during metamorphosis. Contraction of excised arms is reversibly inhibited by treatment with cytochalasin B, and microfilaments bind myosin sub-fragment-1. Indirect immunofluorescence of larval arms using an antibody against chicken-muscle actin and staining with the F-actin specific probe, NDB phallacidin indicate that the arms contain actin distributed in a manner consistent with ultrastructural findings. It is proposed that retraction of the larval arms during metamorphosis is produced by an actin-mediated change in shape of the epidermal cells.
在变态的最初15至20分钟内，幼虫的腕被缩回并吸收到幼体的反口面。从变态幼虫切下的腕会经历一系列收缩和组织溶解过程，这与完整幼虫中发生的过程相同。在变态之前和期间，表皮细胞含有5至7纳米的微丝束，这些微丝束从细胞基部向顶端呈放射状排列。在变态期间固定的幼虫中，稀疏的微丝也出现在表皮细胞和一些间充质细胞的质膜附近。用细胞松弛素B处理可可逆地抑制切下的腕的收缩，并且微丝结合肌球蛋白亚片段-1。使用抗鸡肌肉肌动蛋白抗体对幼虫的腕进行间接免疫荧光以及用F-肌动蛋白特异性探针NDB鬼笔环肽染色表明，腕中肌动蛋白的分布方式与超微结构研究结果一致。有人提出，变态期间幼虫腕的缩回是由肌动蛋白介导的表皮细胞形状变化引起的。
