CELLULAR TARGET SITES OF HEAVY METAL EXPOSED CELLS

这项拟议研究的目的是调查 测试电池中重金属隔间的程度和 确定选定的金属离子对膜的特定作用 结构和细胞器分布。将进行研究 在选定的剂量水平下使用常规的透射式电子 显微镜以确定是否发生了细胞损伤。这个 生物酿酒酵母和普通小球藻将是 暴露在不同浓度的五种环境中- 重要重金属(Cd、铜、汞、铅和锌)，以便 测定暴露在金属中的细胞的EC50。以下是 然后将确定：(1)质膜的程度 从大小、形状、数量、分布等方面分析蚀变 冷冻断裂中发现的基本粒子(蛋白质) 制备，(2)重金属在特定细胞中的定位 使用能量色散X射线空气微量分析的隔间- 干燥和/或冷冻标本，(3)细胞结构， 大多数都是由重金属污染引起的 浓度随机定向形态计量学分析 薄片细胞；以及(4)如果有的话，重金属 通过使用原子吸收分光光度进行定位 从破碎的细胞中提取的部分。 从这些研究的结果来看，预计我们应该 深入了解重金属如何导致某些有害物质 对细胞产生影响。迄今为止对普通小球藻的研究表明 对膜颗粒的分析也可能被Cd改变 与某些其他细胞器和包裹体一样。此信息 应适用于所有细胞水平的重金属效应 包括人类的影响。 人们已经发现，在大多数情况下，任何来源的细胞都有一个 类似的反应。因此，这里获得的蜂窝数据应该是 适用于一定范围内的所有单元格。使用来自的数据 我们的系统应该提供来自哪些蜂窝模型的数据 可以得到对重金属的响应。此信息可以 然后用于包括人类在内的整个动物的反应 当然，对重金属的损害是在细胞水平上的。

It is the purpose of the proposed research to investigate the degree of heavy metal compartmentalization in test cells and to determine selected specific effects of metal ions on membrane structure and organelle distribution. Studies are to be performed at selected dose levels with conventional transmission electron microscopy to determine if cellular damage has occurred. The organisms Saccharomyces cerevisiae and Chlorella vulgaris will be exposed to various concentrations of five environmentally- significant heavy metals (Cd, Cu, Hg, Pb and Zn) in order to determine EC50 of the cells exposed to the metals. The following will then be determined: (1) the degree of plasma membrane alteration by analyses on the size, shape, number and distribution of elementary particles (proteins) revealed in freeze-fracture preparation, (2) heavy metal location in particular cellular compartments using energy-dispersive X-ray microanalysis of air- dried and/or cryosectioned specimens, (3) cell structures which are most altered by the administration of heavy metal concentrations using morphometric analysis of randomly-oriented thin-sectioned cells, and (4) if any, where heavy metals are localized through the use of atomic absorption spectrophotometry on fraction prepared from disrupted cells. From the results of these studies it is anticipated that we should gain insights as to how heavy metals cause certain detrimental affects on cells. Work to date on Chlorella vulgaris indicates that analysis of membrane particles may be altered by Cd as well as certain other cell organelles and inclusions. This information should be applicable to heavy metal effects at all cellular levels including human effects. It has been found that in most cases cells from any source have a similar response. Thus the cellular data obtained here should be applicable to all cells within certain limits. Use of data from our system should provide data from which models of the cellular response to heavy metals can be obtained. This information can then be used in regard to whole animal response including humans to heavy metals as the damage is, of course, at the cellular level.