Replacement of endoplasm with artificial media in plasmodial strands of Physarum polycephalum. Effects on contractility and morphology.
Replacement of endoplasm with artificial media in plasmodial strands of Physarum polycephalum. Effects on contractility and morphology.
复制标题
多头绒泡菌疟原虫链中的内质被人工培养基取代。
DOI：
10.1016/0014-4827(78)90064-2
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发表时间：
1978
影响因子：
3.7
通讯作者：
K. G. Olenhusen
中科院分区：
文献类型：
--
作者：
Tetsuo Ueda;K. G. Olenhusen
多头绒泡菌原质团中的内质被压力移位，并通过将内质推入静脉的其他区域而被人工介质取代。通过测量股线的振荡张力以及它们对该实验过程的形态学响应来研究注入的化学品的影响。结果可以总结如下。1.1.股的横截面显示，几乎所有的内质被注入的介质所取代。用油或空气代替内质后，纤维束继续振荡收缩。但注射后约5-10 min，张力幅度变小。3.3.水溶液（30 mM KCl、3 mM MgCl 2、1 mM CaCl 2、10 mM Tris-HCl，pH 7.1）的内部应用阻止了振荡收缩，并且还引起张力水平的降低。向该溶液中加入ATP诱导振荡收缩，最佳ATP浓度为0.2 mM。注射高浓度ATP导致外质管塌陷。收缩活动和原生质流对注射Ca 2+的最低要求被确定为2 × 10− 7 M，当CaEGTA缓冲液维持游离Ca ~（2+）水平时，ATP和Ca ~（2+）对细胞内Ca ~（2+）的影响结果表明，原生质体的外质管对收缩活性起着重要作用，并与多头绒泡菌肌动球蛋白的ATP酶活性进行了比较并且以水溶液形式注射的化学品比从静脉外施加的化学品更直接地进入收缩系统。
The endoplasm in a plasmodial strand ofPhysarum polycephalumwas translocated with pressure and replaced with artificial media by pushing the endoplasm into other regions of the vein. Effects of injected chemicals were studied by measuring the oscillating tension force of the strands as well as their morphological response to this experimental procedure. The results can be summarized as follows.1.1. Cross sections of the strands show that nearly all of the endoplasm was replaced with injected media.2.2. The oscillatory contraction of the strand continued after replacing the endoplasm with oil or air. However, the amplitude of the tension force became smaller for about 5–10 min after the injection.3.3. An internal application of an aqueous solution (30 mM KCl, 3 mM MgCl2, 1 mM CaCl2, 10 mM Tris-HCl, pH 7.1) arrested the oscillatory contraction and also caused a decrease of the tension force level. An addition of ATP to this solution induced oscillatory contraction, the optimal ATP concentration being 0.2 mM. Injection of a high ATP concentration led to a collapse of the ectoplasmic tube.4.4. The minimal requirement of injected Ca2+for contraction activity as well as for protoplasmic streaming was determined to be 2 × 10−7M, when the free Ca2+level was maintained by CaEGTA buffer.Effects of ATP and Ca2+on the contractility can be compared with those of ATPase activity of extracted actomyosin fromPhysarum polycephalum.Our results indicate that the ectoplasmic tube of a plasmodial strand is responsible for the contraction activity and that the chemicals injected as aqueous solutions have access more directly to the contractile system than those applied from outside the vein.