Abstract
This report describes the process of formation of virus-RNA and virus-protein, and the changes of cyctoplasmic protein and nucleic acid metabolism in the tobacco leaves infected by cucumber mosaic virus.
(1) In the CMV-infected leaves, 15 hours after inoculation, a considerable amount of free infectious RNA is synthesized at first and about 30 minutes later virus particles are formed. Namely, multiplication of the infectious RNA seems to precede the formation of viral-protein after infection.
(2) The amount of free infectious RNA reached the maximum at about 18 hours after inoculation and decreased afterward as a consequence of combining with the protein. But the free infectious RNA was able to be detected slightly after 120 hours.
(3) Soluble cytoplasmic proteins of the inoculated leaves were isolated by paper electrophoresis. Eight fractions were separated from the leaves 72 hours after inoculation, but seven fractions from the healthy leaves. This new component moved faster than others, and was infectious.
(4) Nucleic acids of infected leaves were fractionated by ECTEOLA-cellulose column. Elution was carried out with 0.1M neutral phosphate buffer and NaCl solution in the range of 0.1-1.0M. Each fraction was measured for RNA concentration by the optical density at 200mμ. A new fraction which was not found in the control preparation was isolated from the inoculated leaves 2 days after inoculation. This fraction was eluted with 0.4M NaCl solution and not contained the viral-RNA. It is supposed that CMV-RNA was not eluted as a single fraction by this method.
