Roger A J, Clark C G, Doolittle W F
Canadian Institute for Advanced Research, Department of Biochemistry, Dalhousie University, Halifax, Canada.
Proc Natl Acad Sci U S A. 1996 Dec 10;93(25):14618-22. doi: 10.1073/pnas.93.25.14618.
Trichomonads are anaerobic flagellated protists that, based on analyses of ribosomal RNA sequences, represent one of the earliest branching lineages among the eukaryotes. The absence of mitochondria in these organisms coupled with their deep phylogenetic position has prompted several authors to suggest that trichomonads, along with other deeply-branching amitochondriate protist groups, diverged from the main eukaryotic lineage prior to the endosymbiotic origin of mitochondria. In this report we describe the presence of a gene in Trichomonas vaginalis specifically related to mitochondrial chaperonin 60 (cpn60). A recent study indicates that a protein immunologically related to cpn60 is located in trichomonad hydrogenosomes. Together, these data provide evidence that ancestors of trichomonads perhaps harbored the endosymbiotic progenitors of mitochondria, but that these evolved into hydrogenosomes early in trichomonad evolution.
滴虫是厌氧的有鞭毛原生生物，根据核糖体RNA序列分析，它们是真核生物中最早分支的谱系之一。这些生物中缺乏线粒体，再加上它们在系统发育中的深层位置，促使一些作者提出，滴虫与其他深层分支的无线粒体原生生物群体一起，在线粒体内共生起源之前就从主要的真核生物谱系中分化出来了。在本报告中，我们描述了阴道毛滴虫中存在一个与线粒体伴侣蛋白60（cpn60）特异性相关的基因。最近的一项研究表明，一种与cpn60免疫相关的蛋白质位于滴虫的氢化酶体中。这些数据共同提供了证据，表明滴虫的祖先可能拥有线粒体的内共生祖细胞，但这些祖细胞在滴虫进化早期就进化成了氢化酶体。
