钟形钟虫柄和个体收缩的高速视频电影演示。
High-speed video cinematographic demonstration of stalk and zooid contraction of Vorticella convallaria.
作者信息
Moriyama Y, Hiyama S, Asai H
机构信息
Department of Physics, School of Science and Engineering, Waseda University, Tokyo, Japan.
出版信息
Biophys J. 1998 Jan;74(1):487-91. doi: 10.1016/S0006-3495(98)77806-3.
Stalk contraction and zooid contraction of living Vorticella convallaria were studied by high-speed video cinematography. Contraction was monitored at a speed of 9000 frames per second to study the contractile process in detail. Complete stalk contraction required approximately 9 ms. The maximal contraction velocity, 8.8 cm/s, was observed 2 ms after the start of contraction. We found that a twist appeared in the zooid during contraction. As this twist unwound, the zooid began to rotate like a right-handed screw. The subsequent stalk contraction steps, the behavior of which was similar to that of a damped harmonic oscillator, were analyzed by means of the equation of motion. From the beginning of stalk contraction, the Hookean force constant increased, and reached an upper limit of 2.23 x 10(-4) N/m 2-3 ms after the start of contraction. Thus, within 2 ms, the contraction signal spread to the entire stalk, allowing the stalk to generate the full force of contraction. The tension of an extended stalk was estimated to be 5.58 x 10(-8) N from the Hookean force constant of a stalk. This value coincides with that of the isometric tension of a glycerol-treated V. convallaria, confirming that the contractile system of V. convallaria is well preserved despite glycerol treatment.
利用高速视频摄影技术研究了活体铃壳钟虫的柄收缩和个体收缩。以每秒9000帧的速度监测收缩过程，以详细研究收缩过程。完全的柄收缩大约需要9毫秒。收缩开始2毫秒后观察到最大收缩速度为8.8厘米/秒。我们发现，在收缩过程中个体出现了扭曲。随着这种扭曲展开，个体开始像右旋螺丝一样旋转。通过运动方程分析了随后的柄收缩步骤，其行为类似于阻尼谐振子。从柄收缩开始，胡克力常数增加，并在收缩开始后2 - 3毫秒达到2.23×10⁻⁴牛/米的上限。因此，在2毫秒内，收缩信号扩散到整个柄，使柄能够产生全部收缩力。根据柄的胡克力常数估计，伸展的柄的张力为5.58×10⁻⁸牛。这个值与经甘油处理的铃壳钟虫的等长张力值一致，证实了尽管经过甘油处理，铃壳钟虫的收缩系统仍保存完好。
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