Changes in the magnitude and distribution of forces at different Dictyostelium developmental stages
Changes in the magnitude and distribution of forces at different Dictyostelium developmental stages
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DOI：
10.1002/cm.20262
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发表时间：
2008-04-01
影响因子：
--
通讯作者：
Rieu, J. -P.
中科院分区：
文献类型：
--
作者：
Delanoe-Ayari, H.;Iwaya, S.;Rieu, J. -P.
利用牵引力显微镜测量了不同发育阶段阿米巴盘齿钢柱迁移时所施加的力的分布。通过使用具有高荧光珠密度的非常柔软的聚丙烯酰胺衬底，我们可以测量小至30 Pa的应力。在发展过程中，力量的大小和分布都存在着显著差异。在植物状态下，细胞在速度和形状上呈现周期性的变化，在一个细长的形式和一个更圆的形式之间。在第一种状态下，力更大，特别是当它们在细胞的前后边缘对称分布时。细长的营养细胞也可以呈现前后不对称的受力分布，其中月牙形的细胞后部（尾足）受力最大。预聚集的细胞，一旦极化，只在尾足动物中以最大的力呈现最后一种不对称分布。除了速度外，没有观察到任何循环。在趋化过程中，预聚集细胞的力分布和总体大小都没有改变，后者与营养细胞相似（F-0类似于6 nN）。相反，对于快速移动的聚集单元，力的分布和总体大小都有所改变。特别是，这些高度拉长的细胞施加较低的力（F-0类似于3nn）。在发育的各个阶段，最大力量的位置与文献中描述的Dictyostelium的肌球蛋白II定位一致（Yumura et al., 1984）。使用GFP-myosin Dictyostelium菌株进行初步实验证实了这一结论。
The distribution of forces exerted by migrating Dictyostelium amebae at different developmental stages was measured using traction force microscopy. By using very soft polyacrylamide substrates with a high fluorescent bead density, we could measure stresses as small as 30 Pa. Remarkable differences exist both in term of the magnitude and distribution of forces in the course of development. In the vegetative state, cells present cyclic changes in term of speed and shape between an elongated form and a more rounded one. The forces are larger in this first state, especially when they are symmetrically distributed at the front and rear edge of the cell. Elongated vegetative cells can also present a front-rear asymmetric force distribution with the largest forces in the crescent-shaped rear of the cell (uropod). Pre-aggregating cells, once polarized, only present this last kind of asymmetric distribution with the largest forces in the uropod. Except for speed, no cycle is observed. Neither the force distribution of pre-aggregating cells nor their overall magnitude are modified during chemotaxis, the later being similar to the one of vegetative cells (F-0 similar to 6 nN). On the contrary, both the force distribution and overall magnitude is modified for the fast moving aggregating cells. In particular, these highly elongated cells exert lower forces (F-0 similar to 3 nN). The location of the largest forces in the various stages of the development is consistent with the myosin II localization described in the literature for Dictyostelium (Yumura et al., 1984. J Cell Biol 99:894-899) and is confirmed by preliminary experiments using a GFP-myosin Dictyostelium strain.