Gazarini Marcos L, Sigolo Carlos A O, Markus Regina P, Thomas Andrew P, Garcia Célia R S
Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Súo Paulo, Brasil.
Mem Inst Oswaldo Cruz. 2007 Jun;102(3):329-34. doi: 10.1590/s0074-02762007000300012.
Plasmodium chabaudi malaria parasite organelles are major elements for ion homeostasis and cellular signaling and also target for antimalarial drugs. By using confocal imaging of intraerythrocytic parasites we demonstrated that the dye acridine orange (AO) is accumulated into P. chabaudi subcellular compartments. The AO could be released from the parasite organelles by collapsing the pH gradient with the K+/H+ ionophore nigericin (20 microM), or by inhibiting the H+-pump with bafilomycin (4 microM). Similarly, in isolated parasites loaded with calcium indicator Fluo 3-AM, bafilomycin caused calcium mobilization of the acidic calcium pool that could also be release with nigericin. Interestingly after complete release of the acidic compartments, addition of thapsigargin at 10 microM was still effective in releasing parasite intracellular calcium stores in parasites at trophozoite stage. The addition of antimalarial drugs chloroquine and artemisinin resulted in AO release from acidic compartments and also affected maintenance of calcium in ER store by using different drug concentrations.
查巴迪疟原虫的细胞器是离子稳态和细胞信号传导的主要成分，也是抗疟药物的作用靶点。通过对红细胞内寄生虫进行共聚焦成像，我们证明了吖啶橙（AO）可积聚在查巴迪疟原虫的亚细胞区室中。通过用K+/H+离子载体尼日利亚菌素（20微摩尔）破坏pH梯度，或用巴弗洛霉素（4微摩尔）抑制H+泵，AO可从寄生虫细胞器中释放出来。同样，在加载钙指示剂Fluo 3-AM的分离寄生虫中，巴弗洛霉素引起酸性钙库的钙动员，尼日利亚菌素也可使其释放。有趣的是，在酸性区室完全释放后，添加10微摩尔的毒胡萝卜素仍能有效释放滋养体阶段寄生虫细胞内的钙储存。添加抗疟药物氯喹和青蒿素导致AO从酸性区室释放，并且通过使用不同的药物浓度也影响内质网储存中钙的维持。
