Absolute Amount of Ribonucleic Acid in Virus and Cytoplasmic Particles

Abstract

As Frisch-Niggomeyer¹ has pointed out, many viruses of plant and animal origin seem to contain the same quantity of ribonucleic acid, about 2 X 10⁶ gm. per mole of virus. Recently, cytoplasmic nucleo-protein particles have been isolated from yeast², pea root (Tsao, P., et al., personal communication) and rat liver³. From the particle weight and percentage of nucleic acid found for the particles from either yeast or pea root, a value of 1.7 × 10⁶ gm. for the weight of ribonucleic acid existing in one mole of nucleoprotein may be calculated. A similar amount of ribonucleic acid seems to be contained also in the cytoplasmic particles from rat liver. Thus, in the normal cytoplasmic nucleoprotein particles of both plant and animal origin, the mass of ribonucleic acid appears to be the same and coincides with the amount found in many plant and animal viruses. In view of the diverse origin and very large variations in chemical and morphological complexity and in the absolute amounts of all other chemical constituents, the uniformity of nucleic acid content of these nucleo-proteins is felt to be remarkable.