Small deoxyribonucleic acid-containing viruses (picodnavirus group).

Abstract

THE picornavirus group was established in accordance with the decision of the International Subcommittee on Virus Nomenclature for classifying the major groups of viruses on the basis of common biochemical and biophysical properties1. Picornaviruses contain ribonucleic acid and protein, are insensitive to ether, and are extremely small in size (15–30 mµ in diameter). The capsids of those members of the group the symmetry of which has been studied appear to display cubic symmetry of the icosahedral pattern2. Members of the group derived from humans and lower animals are recognized. Certain plant viruses and the recently isolated RNA-containing bacteriophages have properties which suggest that they might be classified as picornaviruses. The cubic symmetry of the picornaviruses which have been studied is consistent with a capsid constructed from thirty-two morphological sub-units positioned at the vertexes of a rhombic triacontahedron2 (Fig. 1a).