The expression and distribution of dense granule proteins in the enteric (Coccidian) forms of Toxoplasma gondii in the small intestine of the cat
The expression and distribution of dense granule proteins in the enteric (Coccidian) forms of Toxoplasma gondii in the small intestine of the cat
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DOI：
10.1006/expr.1998.4384
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发表时间：
1999-03-01
影响因子：
2.1
通讯作者：
Wright, S
中科院分区：
文献类型：
--
作者：
Ferguson, DJP;Cesbron-Delauw, MF;Wright, S
用免疫光镜和电镜技术研究了致密颗粒蛋白（GRA 1 -6和NTR）在弓形虫裂殖子中的表达和定位，以及弓形虫在猫小肠中的无性和性发育过程。这与中间宿主中存在的速殖子和缓殖子进行了比较。结果表明，裂殖子含有特征性的顶端细胞器和一些大而致密的颗粒。通过免疫细胞化学，致密颗粒在裂殖子GRA蛋白1至6阴性，而速殖子和迟缓子中的致密颗粒对所有6种蛋白均呈阳性。在速殖子和缓殖子发育过程中，GRA蛋白与寄生虫空泡（PV）相关，但在肠期PV中不存在。然而，裂殖子致密颗粒呈NTR阳性，这与速殖子相似，而该抗原在缓殖子中下调。表观释放的NTPases到PV形成的裂殖子也类似于速殖子，可能反映了相对代谢活性的各个阶段。这项研究表明，大多数GRA蛋白具有相似的阶段特异性表达，这是独立的NTPases表达。这些观察结果与T.弓形虫在肠型中具有不同的宿主寄生关系，其不涉及GRA蛋白1-6。(C)北京：科学出版社.
The expression and location of the dense granule proteins (GRA1-6 and NTPase) in the merozoite and during asexual and sexual development of Toxoplasma gondii in the small intestine of the cat (definitive host) was examined by immune-light and electron microscopy. This was compared with that of tachyzoites and bradyzoites present in the intermediate host. It was found that the merozoite contained the characteristic apical organelles plus a few large dense granules. By immunocytochemistry, dense granules in merozoites were negative for GRA proteins 1 to 6 in contrast to both tachyzoites and bradyzoites in which dense granules were positive for all six proteins. The GRA proteins were associated with the parasitophorous vacuole (PV) during tachyzoite and bradyzoite development but were absent from the PV of the enteric stages. However, the merozoite dense granules were positive for NTPase, which was similar to the tachyzoite while this antigen was down regulated in the bradyzoite. The apparent release of the NTPases into the PV formed by merozoites was also similar to that described for the tachyzoite, possibly reflecting the relative metabolic activity of the various stages. This study shows that the majority of GRA proteins have a similar stage-specific expression, which is independent of NTPases expression. These observations are consistent with T. gondii having a different host parasite relationship in the enteric forms, which does not involve the GRA proteins 1-6. (C) 1999 Academic Press.