The present proposal seeks funds for the acquisition of an analytical electron microscope (AEM) and an accessory ultramicrotome to be dedicated primarily for the use of a group of a NIH-sponsored investigators in the Chemistry and Biology Departments. In the AEM a convergent electron beam with a diameter as small as (nanoprobe) can be focused in the specimen plane. Fluorescent x-rays resulting electron bombardment of the specimen can be detected and analyzed in an energy dispersive spectrometer. This analysis will provide qualitative and quantitative information on the elemental composition of the specimen with high spatial resolution. The AEM can also be used to study electron diffraction patterns produced by small crystals or very small selected areas of crystalline material. The projects in which these instruments will be used range from basic studies in cellular physiology and biochemistry to the development of an efficient method for removing toxic contaminants from water. Barrera will study ultrastructural aspects of cellular differentiation in fungi. Birnbaum and Henzl will explore the use of the lanthanide element, europium in AEM for revealing subcellular binding sites for calcium in chromaffin cells. Casillas will attempt to localize the enzyme adenylate cyclase in spermatozoa. Darnall will investigate the subcellular binding sites for heavy metals in algae with the AEM and evaluate the potential use of these organisms in removing toxic substances like mercury and uranium from our water supply. Hageman wishes to localize glycoprotein serine protease in cells of Bacillus subtilis in order to gather more information on the potential role of this enzyme during sporulation in this bacterium. Kuehn will utilize immunocytochemistry to localize calmodulin, transglutaminase, and polyamines in electron micrographs of slime mold cells. Sneddon is interested in using low-angle, selected area electron diffraction to characterize deposits on the surfaces of atomizers used to study biological fluids in atomic absorption spectrophotometry. Villa will study the incorporation of polyurinides with immunocytochemistry and the distribution of calcium with energy dispersive x-ray analysis in fungal cell walls.