Malaria parasites tolerate a broad range of ionic environments and do not require host cation remodelling.
Malaria parasites tolerate a broad range of ionic environments and do not require host cation remodelling.
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DOI：
10.1111/mmi.12159
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发表时间：
2013-04
影响因子：
3.6
通讯作者：
Desai SA
中科院分区：
文献类型：
--
作者：
Pillai AD;Addo R;Sharma P;Nguitragool W;Srinivasan P;Desai SA
疟原虫在红细胞内生长，但在无性复制周期之间也在宿主血浆中游离。因此，寄生虫暴露于波动水平的Na+和K+中，这些离子被认为对人类病原体恶性疟原虫起重要作用。我们通过在新型蔗糖基培养基中建立连续培养来检验这些假设和寄生虫的离子需求。以蔗糖为主要渗透剂，以K+和Cl−为主要细胞外离子，我们获得了与生理培养基中没有区别的寄生虫生长和繁殖速度。这些条件消除了众所周知的通过寄生虫诱导的通道细胞内Na+的增加，排除了红细胞阳离子重塑的需要。我们还分析了Na+、K+和Cl -的需求，发现每种离子的低浓度都能满足寄生虫的需求。令人惊讶的是，生长并没有受到高达148 mM K+的不利影响，这表明低细胞外K+并不是红细胞入侵的必要触发因素。同时，分裂子岩的进入和侵入需要一个阈值离子强度，这表明在这些阶段大分子之间存在关键的静电相互作用。这些发现提供了对疟疾跨膜信号传导的见解，并揭示了宿主和寄生虫离子需求之间的根本差异。
Malaria parasites grow within erythrocytes, but are also free in host plasma between cycles of asexual replication. As a result, the parasite is exposed to fluctuating levels of Na+ and K+, ions assumed to serve important roles for the human pathogen, Plasmodium falciparum. We examined these assumptions and the parasite's ionic requirements by establishing continuous culture in novel sucrose-based media. With sucrose as the primary osmoticant and K+ and Cl− as the main extracellular ions, we obtained parasite growth and propagation at rates indistinguishable from those in physiological media. These conditions abolish long-known increases in intracellular Na+ via parasite-induced channels, excluding a requirement for erythrocyte cation remodeling. We also dissected Na+, K+, and Cl− requirements and found that unexpectedly low concentrations of each ion meet the parasite's demands. Surprisingly, growth was not adversely affected by up to 148 mM K+, suggesting that low extracellular K+ is not an essential trigger for erythrocyte invasion. At the same time, merozoite egress and invasion required a threshold ionic strength, suggesting critical electrostatic interactions between macromolecules at these stages. These findings provide insights into transmembrane signaling in malaria and reveal fundamental differences between host and parasite ionic requirements.
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DOI：
10.1073/pnas.1011560108
发表时间：
2011-01-25
影响因子：
11.1
作者：
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影响因子：
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影响因子：
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