FRET imaging of hemoglobin concentration in Plasmodium falciparum-infected red cells.
FRET imaging of hemoglobin concentration in Plasmodium falciparum-infected red cells.
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DOI：
10.1371/journal.pone.0003780
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发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
Lew VL
中科院分区：
文献类型：
--
作者：
Esposito A;Tiffert T;Mauritz JM;Schlachter S;Bannister LH;Kaminski CF;Lew VL
恶性疟原虫在其红细胞内无性生殖周期中消耗高达80%的宿主细胞血红蛋白，大大超过其代谢需要。恶性疟原虫感染红细胞的稳态模型提出了一种解释，即需要降低宿主细胞内的胶体渗透压，以防止其过早溶解。这一假说的关键是宿主细胞内的血红蛋白浓度从滋养体阶段开始逐渐降低。本文报道的实验旨在通过直接测量受感染的活红细胞中的血红蛋白浓度来验证这一假设。我们开发了一种新型的非侵入性方法来量化单细胞中的血红蛋白浓度，该方法基于血红蛋白分子和荧光团钙黄绿素之间的福斯特共振能量转移。荧光寿命成像允许细胞内血红蛋白浓度的定量映射。未感染组群的平均荧光寿命为270±30 ps（平均值±SD; N = 45）。 在感染细胞的胞质中，钙黄绿素的荧光寿命范围为290±20 ps（环期寄生虫细胞）至590±13 ps（幼滋养体细胞）和1050±60 ps（晚期滋养体/早期滋养体细胞）。这相当于血红蛋白浓度降低，范围为7.3 - 2.3 mM，与模型预测一致。一个意想不到的辅助发现是在具有成熟滋养体阶段寄生虫的细胞中，宿主细胞膜下存在微区，其具有降低的血红蛋白对钙黄绿素的淬灭。结果支持胶体渗透假说的预测，并提供了一个更好的了解疟疾感染的红细胞的稳态。此外，他们揭示了宿主细胞中存在一个独特的外周微区，对血红蛋白分子的接触有限，这表明大量寄生虫输出物质的浓度。
During its intraerythrocytic asexual reproduction cycle Plasmodium falciparum consumes up to 80% of the host cell hemoglobin, in large excess over its metabolic needs. A model of the homeostasis of falciparum-infected red blood cells suggested an explanation based on the need to reduce the colloid-osmotic pressure within the host cell to prevent its premature lysis. Critical for this hypothesis was that the hemoglobin concentration within the host cell be progressively reduced from the trophozoite stage onwards. The experiments reported here were designed to test this hypothesis by direct measurements of the hemoglobin concentration in live, infected red cells. We developed a novel, non-invasive method to quantify the hemoglobin concentration in single cells, based on Förster resonance energy transfer between hemoglobin molecules and the fluorophore calcein. Fluorescence lifetime imaging allowed the quantitative mapping of the hemoglobin concentration within the cells. The average fluorescence lifetimes of uninfected cohorts was 270±30 ps (mean±SD; N = 45). In the cytoplasm of infected cells the fluorescence lifetime of calcein ranged from 290±20 ps for cells with ring stage parasites to 590±13 ps and 1050±60 ps for cells with young trophozoites and late stage trophozoite/ early schizonts, respectively. This was equivalent to reductions in hemoglobin concentration spanning the range from 7.3 to 2.3 mM, in line with the model predictions. An unexpected ancillary finding was the existence of a microdomain under the host cell membrane with reduced calcein quenching by hemoglobin in cells with mature trophozoite stage parasites. The results support the predictions of the colloid-osmotic hypothesis and provide a better understanding of the homeostasis of malaria-infected red cells. In addition, they revealed the existence of a distinct peripheral microdomain in the host cell with limited access to hemoglobin molecules indicating the concentration of substantial amounts of parasite-exported material.
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影响因子：
64.8
作者：
BERENDT, AR;SIMMONS, DL;MARSH, K
通讯作者：
MARSH, K
DOI：
10.1016/0005-2736(93)90172-v
发表时间：
1993-05-14
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
LEW, VL;ETZION, Z;EISINGER, J
通讯作者：
EISINGER, J
影响因子：
2.7
作者：
Hamann, S;Kiilgaard, JF;Zeuthen, T
通讯作者：
Zeuthen, T
影响因子：
2.4
作者：
FORSTER, T
通讯作者：
FORSTER, T
影响因子：
2.3
作者：
Lew, VL;Macdonald, L;Tiffert, T
通讯作者：
Tiffert, T