Regulation of cell shape in Euglena gracilis. II. The effects of altered extra- and intracellular Ca2+ concentrations and the effect of calmodulin antagonists.
Regulation of cell shape in Euglena gracilis. II. The effects of altered extra- and intracellular Ca2+ concentrations and the effect of calmodulin antagonists.
复制标题
纤细眼虫细胞形状的调节。
作者：
T. Lonergan
当纤细裸藻Z.，正常生长于含180 μ M-Ca 2+的培养基中的细胞，重悬于无Ca 2+的培养基中，细胞在10分钟内呈现圆形，当Ca 2+返回到培养物中时，它们缓慢恢复。在10 microM-Ca 2+中生长的培养物不显示细胞形状的典型昼夜节律，即使光合作用和细胞分裂昼夜节律不受影响。通过添加Ca 2+离子载体A23187来提高细胞内Ca 2+水平，可以防止细胞经历生长同步培养物的两个每日形状变化特征，但不会改变维持离子载体添加时发现的细胞形状的能力。当钙调蛋白抑制剂三氟拉嗪或氯丙嗪加入培养物中时，细胞总是以变圆作为反应。在存在这些抑制剂的情况下，细胞不能保持除球形以外的任何细胞形状，因此不能在整个日常周期中改变形状，如在对照群体中发现的那样。
When cultures of Euglena gracilis Z., normally grown in medium containing 180 microM-Ca2+, are resuspended in Ca2+-free medium cells assume round shapes within 10 min, from which they recover slowly when Ca2+ is returned to the cultures. Cultures grown in 10 microM-Ca2+ do not display the typical circadian rhythm in cell shape even though the photosynthesis and cell division circadian rhythms are unaffected. Elevating intracellular Ca2+ levels by the addition of the Ca2+ ionophore A23187 prevents cells from undergoing the two daily shape changes characteristic of growth-synchronized cultures, but does not alter the ability to maintain the cell shapes found at the time of ionophore addition. When the calmodulin inhibitors trifluoperazine or chlorpromazine are added to cultures, the cells always respond by rounding. Cells are not able to maintain any cell shape other than spherical in the presence of these inhibitors and therefore cannot change shape throughout the daily cycle as is found in the control populations.