The cytostome-cytopharynx complex of intracellular and extracellular amastigotes of Trypanosoma cruzi exhibit structural and functional differences
The cytostome-cytopharynx complex of intracellular and extracellular amastigotes of Trypanosoma cruzi exhibit structural and functional differences
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DOI：
10.1111/cmi.13346
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发表时间：
2021-05-18
影响因子：
3.4
通讯作者：
Silva, Narcisa L. Cunha e
中科院分区：
文献类型：
--
作者：
Alcantara, Carolina L.;de Souza, Wanderley;Silva, Narcisa L. Cunha e
克氏锥虫的内吞作用主要是通过一个称为胞口-胞咽复合体的专门的膜结构域进行的。它的超微结构和动态的内吞作用的特点是在epimastigotes，缺乏锥鞭毛体，缺乏内吞活性。细胞内无鞭毛体也具有细胞口-细胞咽，但参与这些形式的内吞作用尚不清楚。细胞外无鞭毛体可以从感染细胞的上清液或体外无鞭毛体发育中获得。这些无鞭毛体与细胞内无鞭毛体共享生化和形态特征，但保留锥鞭毛体建立感染的能力。我们分析和比较了细胞内无鞭毛体和细胞外无鞭毛体的细胞口-细胞咽复合体的超微结构，使用高分辨率三维电子显微镜技术。我们比较了通过宿主细胞裂解获得的细胞内无鞭毛体与细胞外无鞭毛体的内吞能力。细胞内无鞭毛体表现出与外鞭毛体相似的细胞口-细胞咽复合体。然而，分离后，复合物进行超微结构的修改，逐步采取了损害的内吞作用。细胞外无鞭毛体不具有胞口-胞咽复合体，也不具有内吞的能力。这些观察结果突出了细胞内和细胞外无鞭毛体在与细胞代谢相关的重要结构方面的形态功能差异。cruzi细胞内无鞭毛体通过胞口-胞咽复合体进行内吞作用。细胞内无鞭毛体的胞口-胞咽复合体在超微结构上与外鞭毛体相似。细胞内无鞭毛体一旦离开宿主细胞，就会分解胞口-胞咽膜结构域。细胞外无鞭毛体不具有胞口-胞咽膜结构域，也不具有内吞作用。
Endocytosis in Trypanosoma cruzi is mainly performed through a specialised membrane domain called cytostome-cytopharynx complex. Its ultrastructure and dynamics in endocytosis are well characterized in epimastigotes, being absent in trypomastigotes, that lack endocytic activity. Intracellular amastigotes also possess a cytostome-cytopharynx but participation in endocytosis of these forms is not clear. Extracellular amastigotes can be obtained from the supernatant of infected cells or in vitro amastigogenesis. These amastigotes share biochemical and morphological features with intracellular amastigotes but retain trypomastigote's ability to establish infection. We analysed and compared the ultrastructure of the cytostome-cytopharynx complex of intracellular amastigotes and extracellular amastigotes using high-resolution tridimensional electron microscopy techniques. We compared the endocytic ability of intracellular amastigotes, obtained through host cell lysis, with that of extracellular amastigotes. Intracellular amastigotes showed a cytostome-cytopharynx complex similar to epimastigotes'. However, after isolation, the complex undergoes ultrastructural modifications that progressively took to an impairment of endocytosis. Extracellular amastigotes do not possess a cytostome-cytopharynx complex nor the ability to endocytose. Those observations highlight morpho functional differences between intra and extracellular amastigotes regarding an important structure related to cell metabolism.Take AwaysT. cruzi intracellular amastigotes endocytose through the cytostome-cytopharynx complex.The cytostome-cytopharynx complex of intracellular amastigotes is ultrastructurally similar to the epimastigote.Intracellular amastigotes, once outside the host cell, disassembles the cytostome-cytopharynx membrane domain.Extracellular amastigotes do not possess a cytostome-cytopharynx either the ability to endocytose.