Cell Biological, Epidemiological and Clinical Studies on Entamoeba dispar infection

随着溶组织内阿米巴原虫在1997年被重新分类为致病性阿米巴原虫、溶组织内阿米巴原虫和非致病性阿米巴原虫，需要对这些阿米巴原虫及其感染的各个方面进行重新评估。据此，对异速肠杆菌的感染进行了研究。？ 在高温处理下，再用双氧水作为培养物，可以培养出异芽孢杆菌。？ 制备了用于鉴定这两种变形虫的单克隆抗体及其Fab片段。？ 为阐明其生物学特性，对含硫氨基酸的代谢进行了研究。从溶组织菌中克隆了ATP硫化酶基因，并对其重组蛋白进行了鉴定。此外，编码半胱氨酸合成酶的基因从E. dispar中被关闭，这表明存在两个同工型。丝氨酸乙酰转移酶是一种半胱氨酸生物合成的调节酶，我们也用类似的方法对这两种变形虫进行了研究，并对其性质进行了研究。这些研究清楚地表明变形虫是第一个具有功能性半胱氨酸生物合成途径的真核生物。？ 以溶组织芽胞杆菌和入侵芽胞杆菌为模型，研究了多种抑制剂抑制其生长的潜力。结果表明，二硝基苯胺类除草剂和细胞胰酶D均能抑制模型体外生长和胞囊化。？ 流行病学分析显示，住院人群中仅检出溶组织大肠杆菌，但均无症状。

As Entamoeba histolytica was reclassified into pathogenic ameba, Entamoeba histolytica, and nonpathogenic one, Entamoeba dispar in 1997, a variety of aspects of these amebae and their infection needed to be reassessed. Accordingly studies on E. dispar infection was attempted. ? Axenic cultivation of E. dispar could be produced with C. fasciculata treated at high temperature and subsequently with hydrogen peroxide, as a culture associate. ? Monoclonal antobodies and their Fab fragments useful for identification of both amebae were produced. ? To clarify the biological properties, metabolism of sulfur-containing aminoacids was investigated. The gene encoding ATP sulfurylase was cloned from E. histolytica and its recombinant protein was characterized. Moreover, the gene encoding cysteine synthase was closed from E. dispar, which demonstrated the presence of two isoforms. Serine acetyltransferase, a regulatory enzyme of cysteine biosynthesis, was also studies by similar approach for both species of amebae, and the properties investigated. These studies clearly demonstrate amebae were the first eukaryote which has a functional cysteine biosynthetic pathway. ? With E. histolytica and E. invadens as a model, a variety of inhibitors were examined for the potential to suppress the growth. Consequently, dinitroaniline herbicides and cytochlasin D were found to inhibit in vitro growth and encystation of the model. ? By epidemiological analysis, only E. histolytica was detected from institutionalized population though all of them were asymptomatic.