Spermatozoa from the sea urchin, Colobocentrotus atratus, were partially demembranated by extraction with solutions containing Triton X-100 at a concentration which was insufficient to solubilize the membranes completely. The resulting suspension was a mixture containing some spermatozoa in which a proximal, medial, or distal portion of the flagellum was membrane-covered, while the remaining portion was naked axoneme. In reactivating solutions containing 12 µM ATP, only the naked portions of the flagellum became motile. In reactivating solutions containing 0.8 mM ADP, the membrane-covered regions became motile and beat at 6-10 beats/s, while the naked regions remained immobile, or beat very slowly at about 0.3 beat/s. Activation of membrane-covered regions in ADP solutions probably results from the membrane restricting the diffusion of ATP which is formed from ADP by the axonemal adenylate kinase. The results indicate that any region of the flagellum has the capacity for autonomous beating, and that special properties of the basal end of the flagellum are not required for bend initiation. However, the beating of different regions of the flagellum is not completely independent, for in a fair number of spermatozoa the beating of the distal, membrane-covered region in 0.8 mM ADP was intermittent, and was turned on and off in phase with the much slower bending cycle in the proximal region of naked axoneme.
展开▼
机译:通过用含有浓度不足以完全溶解膜的Triton X-100的溶液萃取,部分提取来自海胆Colobocentrotus atratus的精子。所得的悬浮液是含有一些精子的混合物,其中鞭毛的近端,内侧或远端部分被膜覆盖,而其余部分则是裸露的轴突。在重新活化含有12 µM ATP的溶液中,仅鞭毛的裸露部分能活动。在含有0.8 mM ADP的再活化溶液中,被膜覆盖的区域变得活动并以6-10次/秒的速度跳动,而裸露区域保持不动,或以约0.3次/秒的速度非常缓慢地搏动。 ADP溶液中被膜覆盖的区域的激活可能是由于膜限制了ATP的扩散,ATP的扩散是由ADP由轴突腺苷酸激酶形成的。结果表明鞭毛的任何区域都具有自主跳动的能力,并且弯曲起始不需要鞭毛基端的特殊属性。但是,鞭毛不同区域的跳动不是完全独立的,因为在相当多的精子中,在0.8 mM ADP中远端的,被膜覆盖的区域的跳动是间歇性的,并且与大多数裸轴突的近端区域的弯曲周期较慢。
展开▼