The Structure of Tobacco Mosaic Virus as revealed in Ultrathin Sections by Electron Microscopy

Abstract

Oriented preparations of tobacco mosaic virus were treated with uranyl acetate, lanthanum acetate, phosphotungstic acid, phosphomolybdic acid and ammonium vanadate and thin sections from them were studied electronmicroscopically. A hollow canal with a diameter of 30-40 A[degree] located in the interior of the virus rods became visible in long and cross sections. The first two reagents were accumulated predominantly at a distance of 40 A[degree] from the central axis, where according to X-ray studies ribonucleic acid occurs. The other reagents seemed to stain preferentially the protein portions. There were indications of a fine structure with an identity period of 25-30 A[degree]. The canal of the virus particles in the presence of uranyl acetate, on drying, became filled with heavy metal, as Huxley previously observed. The electron microscopic studies confirmed the structural model developed from X-ray data.