Matsumoto Kenji, Takagi Seiji, Nakagaki Toshiyuki
Department of Mathematics, Hokkaido University, Sapporo, Japan.
Biophys J. 2008 Apr 1;94(7):2492-504. doi: 10.1529/biophysj.107.113050. Epub 2007 Dec 7.
We investigate how an amoeba mechanically moves its own center of gravity using the model organism Physarum plasmodium. Time-dependent velocity fields of protoplasmic streaming over the whole plasmodia were measured with a particle image velocimetry program developed for this work. Combining these data with measurements of the simultaneous movements of the plasmodia revealed a simple physical mechanism of locomotion. The shuttle streaming of the protoplasm was not truly symmetric due to the peristalsis-like movements of the plasmodium. This asymmetry meant that the transport capacity of the stream was not equal in both directions, and a net forward displacement of the center of gravity resulted. The generality of this as a mechanism for amoeboid locomotion is discussed.
我们使用模式生物黏菌来研究变形虫如何机械地移动自身的重心。通过为这项工作开发的粒子图像测速程序，测量了整个黏菌原生质流动随时间变化的速度场。将这些数据与黏菌同时运动的测量结果相结合，揭示了一种简单的运动物理机制。由于黏菌的蠕动样运动，原生质的穿梭流动并非真正对称。这种不对称意味着流动在两个方向上的运输能力不相等，从而导致重心产生净向前位移。本文讨论了这一机制作为变形虫运动机制的普遍性。
