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首页> 外文期刊>Infection and immunity >Interactions between Toxoplasma gondii and its host cells: function of the penetration-enhancing factor of toxoplasma.
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Interactions between Toxoplasma gondii and its host cells: function of the penetration-enhancing factor of toxoplasma.

机译：弓形虫与其宿主细胞之间的相互作用：弓形虫渗透增强因子的功能。

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A protein with a molecular weight of 70,000 to 150,000 which was extracted from merozoites of Toxoplasma gondii enhanced the host cell penetration of the merozoites. The optimal pH and temperature for penetration of merozoites coincided with those favoring the action of the penetration-enhancing protein. In addition, a dependence on Ca and Mg existed for penetration of merozoites, either in the presence or absence of this protein. No evidence was found that indicated that the enhancing effect on penetration elicited by the protein was due to increased phagocytic capacity of host cells (HeLa) or improved motility of the merozoites. Electron microscopy demonstrated that the protein, in high concentration, caused disruption of cytoplasmic membranes. In a 100-fold-lower concentration, which still caused a marked enhancement of penetration, no such effect was observed. However, the vacuoles surrounding the penetrated parasites seemed smaller than for merozoites penetrating in cultures to which no penetration-enhancing factor was given, and the membranes limiting the vacuoles demonstrated discontinuities more often. The penetration-enchancing effect of some known enzymes was studies. However, none of these enzymes seemed to correspond to the penetration-enhancing protein of toxoplasma. The mode of entry of toxoplasma merozoites into host cells is discussed. It is concluded that phagocytosis must play a less important role and that merozoites actively penetrate the cytoplasmic membranes of the host cells. The penetration is proposed to be a result of combined mechanical and chemical actions. It is suggested that an enzymatic function of the penetration-enhancing factor released by the merozoites is of importance. The membrane limiting the vacuole of a penetrated merozoite seems to be newly formed in the cell after penetration is completed.
机译：从弓形虫的裂殖子提取的分子量为70,000至150,000的蛋白质增强了裂殖子在宿主细胞中的渗透。裂殖子穿透的最佳pH和温度与有利于增强穿透蛋白作用的pH和温度一致。此外，在存在或不存在这种蛋白质的情况下，裂殖子的穿透都依赖于Ca和Mg。没有证据表明该蛋白引起的对渗透的增强作用是由于宿主细胞（HeLa）的吞噬能力增加或裂殖子的运动性提高所致。电子显微镜显示该蛋白质高浓度引起细胞质膜的破坏。在浓度降低100倍时，仍会导致渗透性显着提高，未观察到这种效果。但是，在没有给予渗透增强因子的培养物中穿透的寄生虫周围的液泡似乎比裂殖子小，并且限制液泡的膜更频繁地显示出不连续性。研究了一些已知酶的渗透促进作用。但是，这些酶似乎都没有与弓形虫的渗透增强蛋白相对应。讨论了弓形虫裂殖子进入宿主细胞的方式。结论是吞噬作用起着次要的作用，裂殖子活跃地穿透宿主细胞的细胞质膜。提议的渗透是机械和化学作用相结合的结果。建议由裂殖子释放的渗透增强因子的酶功能是重要的。渗透完成后，限制渗透的裂殖子液泡的膜似乎在细胞中新形成。

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