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Form-maintaining factors of the trypomastigote of Trypanosoma cruzi

克氏锥虫锥鞭毛体的形态维持因子

基本信息

批准号：
03670195
负责人：
KANBARA Hiroji
金额：
$ 1.28万
依托单位：
Nagasaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

Trypomastigotes of Trypanosoma cruzi developed various functions, by which they can survive in body fluid of mammals. One of the functions is the prompt invasion in host cells such as muscle cells which make trypomastigotes possible to avoid the attack from the host. On the other hand trypomastigotes need to be sucked by an insect ( a kissing bug ) to maintain the species, which require them to stay long in the bloodstream. We found that lowered pH of the MEM medium supplemented 1% bovine serum albumin ( BSA ) accelerated the transformation of the trypomastigote to the amastigote. Using this culture system we have tried to look for the factors that maintain the form of the trypomastigote. First of all we observed the morphological change by electronmicroscopy and confirmed that the accelerated transformation was a physiological reaction but not a denaturation reaction. The immunoblotting using a mouse antiserum to the paraflagellar protein reconfirmed the transformation from trypomastigotes to amastigotes. Trypomastigotes can not survive in the neutral pH medium as well as in the low pH in the absence of BSA. Previously we thought that the effect of BSA was to neutralize the released substances from trypomastigotes which lyse themselves, but it seems to be to stabilize the membrane structure by binding to some surface component. Several serum components ban blind to trypomastigotes besides BSA, but we could not determine which was the most effective for the form maintenance of the trypomastigote. Some protein components of the trypomastigote besides the paraflagellar protein were lost during transformation, one of them was trans-sialidase. At present, however, what is the component maintaining the trypomastigote remains to be solved.

克氏锥虫的锥虫鞭毛具有多种功能，可以在哺乳动物的体液中存活。其功能之一是迅速侵入宿主细胞，如肌肉细胞，这使得锥虫有可能避免来自宿主的攻击。另一方面，锥虫需要被昆虫(接吻的虫子)吸走才能维持物种，这需要它们在血液中停留很长时间。我们发现，在添加1%牛血清白蛋白(BSA)的MEM培养液中，降低pH可加速类鞭毛体向无鞭毛体的转化。利用这个培养系统，我们试图寻找维持锥形鞭毛虫形态的因素。首先，我们用电子显微镜观察了转化的形态变化，证实了加速转化是一种生理反应，而不是变性反应。用小鼠抗鞭毛蛋白抗血清进行的免疫印迹再次证实了从类鞭毛虫到无鞭毛虫的转化。无论是在中性pH介质中，还是在无BSA的低pH环境中，锥虫都不能存活。以前我们认为BSA的作用是中和裂解自身的类鞭毛虫释放的物质，但它似乎是通过与某些表面成分结合来稳定膜结构。除BSA外，其他几种血清成分对类鞭毛虫均无抑制作用，但我们不能确定哪种成分对类鞭毛虫的形态维持最有效。在转化过程中，锥体鞭毛体的一些蛋白质组分除了侧翼蛋白外还丢失了，其中一种是转唾液酸酶。然而，目前维持类鞭毛体的成分是什么仍有待解决。