Calcium signal regulates temperature-dependent transformation of sporozoites in malaria parasite development

The infection by the malaria parasite of its mammalian host is initiated by the asexual reproduction of the parasite within the host hepatocyte. Before the reproduction, the elongated sporozoites undergo a depolarizing morphogenesis to the spherical exo-erythrocytic form (EEF). This change can be induced in vitro by shifting the environmental conditions, in the absence of host hepatocytes. Using rodent malaria parasites expressing a FRET-based calcium sensor, YC3.60, we observed that the intracellular calcium increased at the center of the bulbous structure during sporozoite transformation. Modulators of intracellular calcium signaling (A23187 and W-7) accelerated the sporozoite-rounding process. These data suggest that calcium signaling regulates the morphological development of the malaria parasite sporozoite to the EEF, and support a fundamental role for calcium as a universal transducer of external stimuli in the parasitic life cycle. (C) 2011 Elsevier Inc. All rights reserved.

疟原虫对其哺乳动物宿主的感染是由寄生虫在宿主肝细胞内的无性繁殖引发的。在繁殖之前，细长的子孢子会经历一种去极化的形态发生过程，转变为球形的红外期形式（EEF）。在没有宿主肝细胞的情况下，通过改变环境条件可在体外诱导这种变化。利用表达基于荧光共振能量转移（FRET）的钙传感器YC3.60的啮齿类疟原虫，我们观察到在子孢子转化过程中，细胞内钙在球状结构的中心增加。细胞内钙信号调节剂（A23187和W - 7）加速了子孢子变圆的过程。这些数据表明，钙信号调节疟原虫子孢子向红外期形式的形态发育，并支持钙作为寄生虫生命周期中外部刺激的通用转换器这一基本作用。（C）2011爱思唯尔公司。保留所有权利。