Lindemann C B, Walker J M, Kanous K S
Department of Biological Sciences, Oakland University, Rochester, MI 48309-4401, USA.
Cell Motil Cytoskeleton. 1995;30(1):8-16. doi: 10.1002/cm.970300103.
Bull sperm extracted with 0.1% Triton X-100 can be reactivated to full motility with 0.33 mM Mg-ATP (sperm models). When motile sperm models are treated with 0.66 mM NiSO4, spontaneous motility is lost. During the transition to motility arrest, the beat becomes progressively more asymmetric, finally arresting at one extreme of the beat cycle. After spontaneous motility has been lost, the flagellum retains the ability to respond to mechanical stimulation. If a microprobe is used to bend the flagellum in the direction opposite to its own prevailing curvature and released, the recoil is rapid and overshoots the equilibrium position. When the same flagellum is manipulated in the opposite direction (into a tighter bend of the existing curve), the recoil is slower and does not exceed the initial bend. If a microprobe is used to carefully bend the whole flagellum into a curve, the flagellum will resume continuous beating, but only if the imposed bend is in the direction opposite the natural curvature. The reinstated beating activity (mechanical reactivation) is sustained as long as the flagellum is held by the microprobe. The rate of change of the shear angle in these mechanically reactivated, Ni(2+)-inhibited sperm suggests an impaired rate of sliding on one side of the axoneme compared to similarly restrained control sperm. It appears that Ni2+ has a selective inhibitory effect on the dynein arms that bend the flagellum in one direction. Furthermore, the remaining functional arms activate only when the flagellum is bent in the direction opposing their own action.
用0.1% Triton X - 100提取的公牛精子可通过0.33 mM Mg - ATP重新激活至完全运动能力（精子模型）。当运动精子模型用0.66 mM NiSO4处理时，自发运动能力丧失。在向运动停止转变的过程中，摆动逐渐变得更加不对称，最终在摆动周期的一个极端停止。自发运动能力丧失后，鞭毛仍保留对机械刺激作出反应的能力。如果用微探针将鞭毛朝着与其自身主要弯曲方向相反的方向弯曲并释放，回缩迅速且超过平衡位置。当同一鞭毛朝相反方向（弯成现有曲线更紧的弯曲）操作时，回缩较慢且不超过初始弯曲。如果用微探针小心地将整个鞭毛弯成曲线，鞭毛将恢复持续摆动，但前提是施加的弯曲方向与自然弯曲方向相反。只要鞭毛被微探针固定，恢复的摆动活动（机械再激活）就会持续。与同样受到限制的对照精子相比，这些经机械再激活、Ni(2+)抑制的精子中剪切角的变化速率表明轴丝一侧的滑动速率受损。似乎Ni2+对使鞭毛向一个方向弯曲的动力蛋白臂具有选择性抑制作用。此外，剩余的功能臂仅在鞭毛朝着与其自身作用相反的方向弯曲时才激活。
