Benzonana G, Campanella C, Gabbiani G
Histochemistry. 1979 Feb 26;60(1):21-41. doi: 10.1007/BF00495726.
Crayfish muscle, like muscles from some other invertebrates, can supercontract. This muscle shortening is characterized by an overlap of thin filaments with crossing of thick filaments through the Z discs. In intact muscle cells, supercontraction does not seem to induce irreversible structural modifications in the tissue. Isolated crayfish myofibrils in the relaxed state cannot be distinguished from vertebrate myofibrils under light microscope, either by phase contrast or by immunofluorescence, with antiactin antibodies, actin being localized in the I bands. However, when isolated crayfish myofibrils are supercontracted, irreversible dammage occurs, most thin filaments being lost. Actin becomes then hardly detectable, being visible, by immunofluorescence, either in the Z discs or evenly distributed in the whole myofibril. During myofibril supercontraction, high amounts of denatured actin, become soluble as shown by SDS-PAGE, by double immunodiffusion, and by DNAse inhibition.
小龙虾肌肉与其他一些无脊椎动物的肌肉一样，能够进行超收缩。这种肌肉缩短的特征是细肌丝重叠，粗肌丝穿过Z盘。在完整的肌肉细胞中，超收缩似乎不会在组织中诱导不可逆的结构改变。在光学显微镜下，无论是通过相差显微镜还是免疫荧光法，用抗肌动蛋白抗体检测，处于松弛状态的分离小龙虾肌原纤维与脊椎动物肌原纤维无法区分，肌动蛋白位于I带。然而，当分离的小龙虾肌原纤维发生超收缩时，会出现不可逆的损伤，大多数细肌丝会丢失。此时，肌动蛋白几乎无法检测到，通过免疫荧光法观察，其要么出现在Z盘中，要么均匀分布在整个肌原纤维中。在肌原纤维超收缩过程中，大量变性的肌动蛋白变得可溶，这通过SDS - PAGE、双向免疫扩散和DNA酶抑制实验得以证明。
