Pacheco-Soares C, de Souza W
Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil.
Parasitol Res. 2000 Jul;86(7):529-36. doi: 10.1007/s004360000198.
The attachment of tachyzoites of Toxoplasma gondii to the surface of host cells induces the formation of a vacuole known as the parasitophorous vacuole (PV). In the present study we used lectins labeled with either fluorescein or colloidal gold particles to follow the fate of lectin-binding sites on the host-cell surface during the process of parasite/host-cell interaction. The results obtained indicate that few, if any, lectin-binding sites are internalized together with the tachyzoites to make part of the PV membrane. However, these sites are internalized and observed in small vesicles that are seen close to the PV. We also used the freeze-fracture technique in cells treated with saponin, which reveals cholesterol-containing sites as easily identifiable elongated sulculi and depressions. Intramembranous particles, which represent membrane integral proteins, were seen in the membrane lining the PV. However, saponin-cholesterol complexes were not observed in the membrane lining the PV, although they were seen in the parasite membranes. These observations, in association with data from previous studies, show that some, but not all, membrane components of the host cell contribute to the formation of the PV membrane.
刚地弓形虫速殖子附着于宿主细胞表面会诱导形成一种称为寄生泡（PV）的液泡。在本研究中，我们使用了用荧光素或胶体金颗粒标记的凝集素，以追踪在寄生虫/宿主细胞相互作用过程中宿主细胞表面凝集素结合位点的命运。获得的结果表明，即使有，也只有极少数凝集素结合位点会与速殖子一起内化，成为PV膜的一部分。然而，这些位点会被内化，并在靠近PV处可见的小泡中观察到。我们还对用皂素处理的细胞使用了冷冻蚀刻技术，该技术可将含胆固醇的位点显示为易于识别的细长沟和凹陷。在PV内衬膜中可见代表膜整合蛋白的膜内颗粒。然而，尽管在寄生虫膜中可见皂素 - 胆固醇复合物，但在PV内衬膜中未观察到。这些观察结果与先前研究的数据相结合，表明宿主细胞的一些而非全部膜成分有助于PV膜的形成。
