Mechanism of determination of the flagellar beat plane.

真核生物鞭毛的运动是基于轴丝中的双线微管之间的滑动。为了诱导平面弯曲，应该控制轴丝内的滑动量，使得轴丝表现得好像由两组偶极子组成。为了研究平面弯曲的形成机制，我们采用了一种新的实验方法，海胆精子鞭毛。我们已经发现，在一个实验条件下，鞭毛的拍平面可以旋转几个周期，在该实验条件下，用吸力保持精子头部的微量吸管被振动，并且这种施加的振动的平面被旋转。在振动停止后，拍平面的自发恢复发生。在活鞭毛中，拍平面旋转多达11个周期之后，这种自发的反向旋转。传统Triton模型的拍平面旋转不超过一个周期，但是用含有CHAPS和Nonidet P-40的溶液脱膜的再活化精子的拍平面沿着振动平面旋转沿着超过10个周期。振动停止后鞭毛的响应随振动平面的旋转方向而变化：逆时针旋转之后是完全解绕，但顺时针旋转之后是部分解绕。退绕的初始速度在两个方向上是相同的，并且是施加的卷绕的转数的函数。由于附着在轴丝上的聚苯乙烯珠在旋转过程中不绕轴丝旋转，所以9个双联体不太可能绕轴丝轴旋转。这些结果表明，鞭毛可以通过改变轴丝内的主动滑动模式来改变节拍平面，这可能与中央小管的旋转有关。

Eukaryotic flagellar movements are based on sliding between doublet microtubules in the axoneme. To induce a planar bend, the amount of sliding within the axoneme should be controlled so that the axoneme behaves as if it were composed of two groups of doublets. To study the mechanism of the formation of the planar bends, we applied a new experimental procedure to sea urchin sperm flagella. We have found that the beat plane of the flagella can be rotated over several cycles under an experimental condition in which the micropipette which held the sperm head with suction is vibrated and the plane of this imposed vibration is rotated. Spontaneous recovery of the beat plane occurs after the cessation of the vibration. As many as 11 cycles of revolution of the beat plane were followed by such spontaneous reverse rotations in live flagella.The beat plane of conventional Triton models did not rotate for more than one revolution, but that of reactivated sperm that had been demembranated with a solution containing CHAPS and Nonidet P-40 rotated along with the plane of vibration for more than 10 revolutions. The response of the flagellum after a cessation of the vibration varied with the direction of rotation of the vibration plane: counterclockwise rotations were followed by a complete unwinding but clockwise rotations were followed by a partial unwinding. The initial velocity of unwinding was the same in both directions and was a function of the number of revolutions of the imposed winding. since the polystyrene beads attached to the axoneme did not rotate around the axoneme during the rotation, it is unlikely that the 9 doublets rotate around the axonemal axis. These results indicate that the flagellum can change the beat plane by changing the pattern of active sliding within the axoneme, possibly in association with rotation of the central tubules.