Electron Microscopic Observation on Dolichos Enation Mosaic Virus

Sap from plants infected with a strain (NDEMV) of dolichos enation mosaic virus (DEMV) contains many ringlike particles, but few particles of about 3000 Å, the normal length for viruses of the tobacco mosaic virus group. In purified preparations the mean length of normal particles of NDEMV was 3000 Å and that of DEMV, 2860 Å. Staining with uranyl formate clearly revealed the fine structure of these particles and in the ringlike particles it penetrated to the expected position of the ribonucleic acid.