Pagh K I, Adelman M R
Department of Anatomy, Duke University Medical Center, Durham, North Carolina.
Cell Motil Cytoskeleton. 1988;11(4):223-34. doi: 10.1002/cm.970110402.
The amoeboflagellate transformation in Physarum polycephalum involves a series of dramatic changes in cell shape and motile behavior. This report describes the morphological and behavioral changes through which a synchronously transforming population of cells passes, stressing that, although there are a series of distinguishable stages, cells at all stages display striking plasticity. Our previous studies showed that amoeboflagellates transiently display a flattened motile extension--the ridge--that projects from a specific location on the cell surface and contains a laminar core densely packed with a series of crisscrossing arrays of actin microfilaments. Details are presented here concerning the movements of the ridge as well as the dynamics of ridge formation and disassembly in relation to other morphogenetic events of the transformation. The ridge forms at about the same time as transforming cells begin to elongate, propagates undulations parallel to the long axis of the cell as the transformation proceeds, and disassembles late in the transformation. Staining of fixed cells with the fluorescent probe rhodaminephalloidin shows that the actin of amoeboid cells is strikingly redistributed as the transformation proceeds. Amoeboflagellates contain most of the stainable actin in the ridge and in a ventral-posterior spot that may be a site of cell-substratum adhesion. These results provide additional insights into the possible functions of the ridge and the roles of actin during the amoeboflagellate transformation.
多头绒泡菌的变形虫鞭毛虫转化涉及细胞形状和运动行为的一系列显著变化。本报告描述了同步转化的细胞群体所经历的形态和行为变化，强调尽管存在一系列可区分的阶段，但所有阶段的细胞都表现出显著的可塑性。我们之前的研究表明，变形虫鞭毛虫短暂地展示出一个扁平的运动延伸——嵴，它从细胞表面的特定位置突出，并且包含一个层状核心，其中密集排列着一系列纵横交错的肌动蛋白微丝阵列。本文详细介绍了嵴的运动以及嵴的形成和分解动力学与转化过程中其他形态发生事件的关系。嵴大约在转化细胞开始伸长时形成，随着转化的进行，沿着细胞的长轴传播波动，并在转化后期分解。用荧光探针罗丹明鬼笔环肽对固定细胞进行染色显示，随着转化的进行，变形虫细胞的肌动蛋白显著重新分布。变形虫鞭毛虫在嵴以及可能是细胞与底物粘附位点的腹后斑点中含有大部分可染色的肌动蛋白。这些结果为嵴的可能功能以及肌动蛋白在变形虫鞭毛虫转化过程中的作用提供了更多见解。
