Detergent-Extracted Volvox model exhibits an anterior-posterior gradient in flagellar Ca2+ sensitivity
Detergent-Extracted Volvox model exhibits an anterior-posterior gradient in flagellar Ca2+ sensitivity
复制标题
洗涤剂提取的沃尔沃克斯模型表现出鞭毛 Ca2 敏感性的前后梯度
DOI：
10.1073/pnas.1715489115
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发表时间：
2018
影响因子：
11.1
通讯作者：
Wakabayashi K.
中科院分区：
文献类型：
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作者：
Ueki N;Wakabayashi K.
团藻是一种多细胞的球形绿色藻，含有约5，000个细胞，每个细胞具有两个鞭毛（纤毛）。这种生物体在没有任何已知的细胞间通讯的情况下表现出惊人的光行为。为了帮助理解鞭毛的行为是如何调节的，我们开发了一种方法，用洗涤剂提取整个生物体并重新激活其鞭毛运动。加入ATP后，球状体中的脱膜鞭毛（轴丝）活跃地跳动，球状体像活的一样游动。在无钙条件下，轴丝呈平面和不对称的波形，并向后极跳动，在没有光刺激的情况下，活球体也是如此。然而，在10− 6 M Ca 2+存在的情况下，大多数轴丝以三维方式朝向前极跳动，类似于光刺激的活球体中的鞭毛。这种依赖于Ca 2+的鞭毛跳动方向的变化在球体的前极附近更明显，但在后极附近没有观察到。鞭毛对Ca ~（2+）敏感性的这种前后梯度可以解释V. Rousseletiiiphotobehavior.
Volvox rousseletiiis a multicellular spheroidal green alga containing ∼5,000 cells, each equipped with two flagella (cilia). This organism shows striking photobehavior without any known intercellular communication. To help understand how the behavior of flagella is regulated, we developed a method to extract the whole organism with detergent and reactivate its flagellar motility. Upon addition of ATP, demembranated flagella (axonemes) in the spheroids actively beat and the spheroids swam as if they were alive. Under Ca2+-free conditions, the axonemes assumed planar and asymmetrical waveforms and beat toward the posterior pole, as do live spheroids in the absence of light stimulation. In the presence of 10−6M Ca2+, however, most axonemes beat three-dimensionally toward the anterior pole, similar to flagella in photostimulated live spheroids. This Ca2+-dependent change in flagellar beating direction was more conspicuous near the anterior pole of the spheroid, but was not observed near the posterior pole. This anterior–posterior gradient of flagellar Ca2+sensitivity may explain the mechanism ofV. rousseletiiphotobehavior.