ION CONCENTRATIONS IN TRYPANOSOMA CRUZI

不同隔室的元素含量 克氏锥虫表鞭毛体用QUICK 冷冻、超冷冻显微手术、X射线显微分析和 扫描透射式电子中的成分映射 显微镜。高电子密度鉴定的空泡中含有 大量的磷，以及二价阳离子，镁， 钙和锌。没有其他隔间有明显的钙 或锌含量。铁只在液泡中检测到，与 电子致密的液泡和其他细胞器。要确定 富钙和富铁液泡在细胞内的分布 锥虫，使用电子技术收集组成图 能量损失谱-成像。在这项技术中，光谱被 对每个像素进行分析，以获得钙和铁的分布。 离子霉素+黑霉素在培养液中培养细胞 导致2-3个因子中钾的电子密度增加 液泡和富含铁的液泡中。这一发现表明 液泡的酸性性质，并证明了 电子致密的液泡对应于酸性钙体，即 富含钙的酸性隔间，已被表征 生物化学上的，但尚未从形态上鉴定。这个 X射线分析和元素图谱提供了证据 酸性钙体是不同于溶酶体或其他 以前在这些寄生虫中描述的细胞器是 导致查加斯病的病原体。这是《墙内》的延续 研究项目Z01-RR-10479-02 BEI。

The elemental content of different compartments of Trypanosoma cruzi epimastigotes has been measured by quick freezing, ultracryomicrotomy, x-ray microanalysis and compositional mapping in the scanning transmission electron microscope. Vacuoles identified by high electron-density contained large amounts of phosphorus, and the divalent cations, magnesium, calcium and zinc. No other compartment had appreciable calcium or zinc content. Iron was detected only in vacuoles distinct from the electron-dense vacuoles and other organelles. To determine the distribution of calcium-rich and iron-rich vacuoles within the trypanosomes, compositional maps were collected using electron energy loss spectrum-imaging. In this technique, spectra were analyzed at each pixel to obtain distributions of calcium and iron. Incubation of cells in culture medium with ionomycin plus nigericin led to factor of 2-3 increase in potassium in the electron-dense vacuoles and in the iron-rich vacuoles. This finding indicated the acidic nature of the vacuoles and demonstrated that the electron-dense vacuoles correspond to the acidocalcisome, i.e., an acidic compartment rich in Ca2+, that has been characterized biochemically but has not been identified morphologically. The x-ray analysis and elemental mapping provide evidence that acidocalcisomes are organelles different from lysosomes or other organelles previously described in these parasites which are the agent causing Chagas' disease. This is a continuation of Intramural Research Project Z01-RR-10479-02 BEI.