The effect of partial extraction of dynein arms on the movement of reactivated sea-urchin sperm.
The effect of partial extraction of dynein arms on the movement of reactivated sea-urchin sperm.
复制标题
部分提取动力蛋白臂对重新激活的海胆精子运动的影响。
作者：
B. H. Gibbons;I. Gibbons
在Triton X-100存在下，海胆精子在室温下用0.5M KCl45 S提取，然后转移到含有1mM三磷酸腺苷的复活液中。经KCl2提取的精子鞭毛搏动频率(16次/S)仅为未暴露于0.5MKCl的对照Triton提取精子(31次/S)的一半左右，但其弯曲波的形状并未发生明显变化。电子显微镜检查显示，用0.5M氯化钾提取后，大部分外臂从双小管上移走，内臂明显完好无损。通过改变KCl-提取的时间，表明拍频的下降速度与手臂的消失速度是平行的。在室温下延长提取时间超过45 S，或在0℃下提取4min，对拍频影响不大。ATPase测定表明，当允许用KCl提取完成时，原始轴丝中有60%-65%的动力蛋白已被溶解。这些结果表明，基本典型形式的鞭毛弯曲波的产生和传播不能通过从双线小管中移除动力蛋白臂的外排来阻止。根据鞭毛弯曲的滑动细丝模型，结果表明，在这种条件下，小管之间的滑动速度与动力蛋白臂的数量成正比。波形没有显著变化意味着，在每个弯曲周期中发生的滑动量不受动力蛋白臂数量减少的影响，而是以某种方式独立地受到弯曲轴丝中其他结构产生的弹性力的调节。
Sea-urchin sperm were extracted with o.5 M KCl for 45 s at room temperature in the presence of Triton X-100, and then transferred to reactivating solution containing 1 mM ATP. The flagellar beat frequency of these KCl-extracted sperm (16 beats/s) was only about half that of control Triton-extracted sperm that had not been exposed to 0.5 M KCl (31 beats/s), although the form of their bending waves was not significantly altered. Examination by electron microscopy showed that the extraction with 0.5 M KCl removed the majority of the outer arms from the doublet tubules, leaving the inner arms apparently intact. By varying the duration of the KCl-extraction, it was shown that the rate of decrease in beat frequency paralleled the rate of disappearance of the arms. Prolonging the extraction time beyond 45 s at room temperature, or 4 min at o °C, had little further effect on beat frequency. ATPase measurements suggested that 6o-65% of the dynein in the original axonemes had been solubilized when the extraction with KCl was permitted to go to completion. These results indicate that the generation and propagation of flagellar bending waves of essentially typical form are not prevented by the removal of the outer row of dynein arms from the doublet tubules. In terms of the sliding filament model of flagellar bending, the results suggest that the rate of sliding between tubules under these conditions is proportional to the number of dynein arms present. The lack of significant change in wave form implies that the total amount of sliding that occurs during each bending cycle is not affected by the reduced number of dynein arms, but is regulated independently in some manner by the elastic forces generated by other structures in the bent axoneme.