No abstract

No abstract

Our aim is to use Scanning Transmission Electron Microscopy (STEM) for research on biological macromolecules. Preliminary experiments have been carried out on a Philips EM 300 (equipped with a high resolution stage and normal hairpin cathode) with a STEMattachment. The elastically scattered electrons were detected on an annular detector and the images were photographed from the monitor screen. The instrumental resolution was about 15Å. The biological macromolecules were mounted on a carbon film with a thickness of about 25Å supported by a holey film; in most cases the objects were lightly (negatively) stained with uranyl acetate (UAc).Fig. 1 shows a STEM-dark field (df) image of lightly stained rooster liver (poly-) ribosomes. The mRNA can be seen; this is remarkable considering the instrumental resolution. The subunits cannot be seen; however we hope to succeed in visualizing the substructure of the ribosome by lightly negative staining.

No abstract