Electron microscope images of mercury atoms bound to DNA filament

Ultra-fine grids with holes of a few hundred angstroms in diameter were made from tropomyosin for specimen supporting media. DNA was mounted on the grid. Microscope images were obtained demonstrating one double-stranded DNA filament bridging a hole. Using mercurated DNA a few filamentous images were observed in a bridge, and series of faint fine sports were recognized along an edge of a hole. These spots were interpreted as the images of single mercury atoms bound to the filament. The control experiment was made on unstained DNA, some images of which showed only uniform intensity over the bridge, whereas others were disturbed to some extent by noise presumably due to extraneous molecules coating the filament.