Mechanism of determination of the flagellar beat plane.

真核生物鞭毛的运动是基于轴突中双线微管之间的滑动。为了诱导平面弯曲，轴突内的滑动量应该被控制，使轴突表现得好像它是由两组双线组成的。为了研究平面弯曲的形成机制，我们对海胆精子鞭毛进行了新的实验。我们发现鞭毛的跳动平面在实验条件下可以旋转几个周期，在这个实验条件下，用吸力握住精子头的微吸管被振动，这个强加的振动平面被旋转。振动停止后，振动面会自发恢复。在活鞭毛中，这种自发的反向旋转伴随着跳动面多达11个周期的旋转。传统Triton模型的振动面旋转不超过一圈，但用含有CHAPS和Nonidet P-40的溶液去膜的活化精子的振动面旋转超过10圈。振动停止后鞭毛的响应随振动面旋转方向的变化而变化：逆时针旋转后完全解绕，顺时针旋转后部分解绕。放卷的初始速度在两个方向上是相同的，并且是施加的绕卷转数的函数。由于附着在轴突上的聚苯乙烯小珠在旋转过程中没有绕轴突旋转，因此9个双偶体不太可能绕轴突轴旋转。这些结果表明，鞭毛可以通过改变轴突内主动滑动的模式来改变跳动平面，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.