Free Ca2+ and cytoplasmic streaming in the alga Chara
Free Ca2+ and cytoplasmic streaming in the alga Chara
复制标题
藻类轮藻中的游离 Ca2 和细胞质流
作者：
R. Williamson;C. Ashley
植物细胞与动物细胞一样，含有钙离子结合蛋白钙调素1 -4。通过与动物细胞的类比，已经表明细胞内游离Ca 2+浓度可能在植物细胞活性的调节中具有重要作用。这一建议已得到各种生理实验的支持，但到目前为止，尚未获得直接证据，涉及细胞内Ca 2+水平的测量。我们在这里描述的测量细胞内钙在巨大的轮藻的蛋白质水母发光蛋白，它发出蓝光的比例Ca 2+浓度的显微注射。轮藻具有ATP依赖的细胞质流动，可被Ca ~（2+）抑制（参考文献5、6）。我们报告说，轮藻细胞有一个低的游离Ca 2+浓度，与动物细胞，和动作电位，抑制细胞质streaming 7增加这个Ca 2+浓度大幅。
Plant cells, like those of animals, contain the Ca2+-binding protein calmodulin1–4. By analogy with animal cells it has thus been suggested that the intracellular free Ca2+ concentration may have an important role in the regulation of plant cell activities. This suggestions has been supported by various physiological experiments, but so far direct evidence, invol ving measurements of intracellular Ca2+ levels, has not been obtained. We describe here measurements of intracellular Ca2+ in the giant alga Chara by microinjection of the protein aequorin, which emits blue light in proportion to Ca2+ concentration. Chara exhibit an ATP-dependent cytoplasmic streaming shown to be inhibited by Ca2+ (refs 5, 6). We report that Chara cells have a low free Ca2+ concentration, comparable with those of animal cells, and that action potentials which inhibit cytoplasmic streaming7 increase this Ca2+ concentration substantially.