Figure 4-1. Electron micrographs of polyhedral organelles purified from S. enterica. A.
           Low-magnification (53,OOOX) electron micrograph of polyhedral organelles.
           B. High-magnification 122,OOOX) micrograph of polyhedral organelles. The polyhedra are approximately 100-150 nm in diameter and are composed of an
           interior filled with heterogeneous particles surrounded by a 3-4 nm thick
           protein shell. The bars in the lower right-hand corners are 100 nm in length.
           Prior to electron microscopy, organelles were fixed with Trump's reagent and
           then negatively stained with uranyl-acetate.