Time-lapse video microscopy of gliding motility in Toxoplasma gondii reveals a novel, biphasic mechanism of cell locomotion
Time-lapse video microscopy of gliding motility in Toxoplasma gondii reveals a novel, biphasic mechanism of cell locomotion
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DOI：
10.1091/mbc.10.11.3539
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发表时间：
1999-11-01
影响因子：
3.3
通讯作者：
Sibley, LD
中科院分区：
文献类型：
--
作者：
Håkansson, S;Morisaki, H;Sibley, LD
弓形虫是弓形虫复合门的一员，这是一组不同的细胞内寄生虫，共享一种独特的滑动运动形式。滑行依赖于底物，在没有传统运动细胞器的情况下，细胞形状没有明显变化。在这里，我们证明了滑翔的特点是三种不同的运动形式：圆周滑行、直立旋转和螺旋旋转。当新月形的寄生虫向右倾斜时，它开始作圆周滑行，从那里开始，它以逆时针的方式移动，移动的速度类似于1.5亩/S。当寄生虫垂直地自我调整时，就会发生旋转，通过它的后端附着在底物上，然后顺时针旋转。螺旋滑行类似于旋转，不同之处在于它是在寄生虫水平定位时发生的，导致向前移动遵循开瓶器的路径。寄生虫开始左侧躺着(凸侧被定义为背侧)，并沿着新月形身体的长轴顺时针旋转。延时视频分析表明，螺旋滑行是一个两相过程。在转弯的前180度，寄生虫以类似于1-3微米/秒的速度向前移动一个身体长度。在第二阶段，寄生虫向左侧翻转，在这个过程中经历了很小的净向前运动。这三种形式的运动都被肌动蛋白细丝(细胞松弛素D)和肌球蛋白ATPase(丁二酮单肟)的抑制剂破坏，这表明它们依赖于寄生虫中的放线肌球蛋白马达。滑动运动可能提供主动穿透宿主细胞的力量，并可能参与宿主内的传播，因此具有根本和实际意义。
Toxoplasma gondii is a member of the phylum Apicomplexa, a diverse group of intracellular parasites that share a unique form of gliding motility. Gliding is substrate dependent and occurs without apparent changes in cell shape and in the absence of traditional locomotory organelles. Here, we demonstrate that gliding is characterized by three distinct forms of motility: circular gliding, upright twirling, and helical rotation. Circular gliding commences while the crescent-shaped parasite lies on its right side, from where it moves in a counterclockwise manner at a rate of similar to 1.5 mu m/s. Twirling occurs when the parasite rights itself vertically, remaining attached to the substrate by its posterior end and spinning clockwise. Helical gliding is similar to twirling except that it occurs while the parasite is positioned horizontally, resulting in forward movement that follows the path of a corkscrew. The parasite begins lying on its left side (where the convex side is defined as dorsal) and initiates a clockwise revolution along the long axis of the crescent-shaped body. Time-lapse video analyses indicated that helical gliding is a biphasic process. During the first 180 degrees of the turn, the parasite moves forward one body length at a rate of similar to 1-3 mu m/s. in the second phase, the parasite flips onto its left side, in the process undergoing little net forward motion. All three forms of motility were disrupted by inhibitors of actin filaments (cytochalasin D) and myosin ATPase (butanedione monoxime), indicating that they rely on an actinomyosin motor in the parasite. Gliding motility likely provides the force for active penetration of the host cell and may participate in dissemination within the host and thus is of both fundamental and practical interest.