Comparative studies on tomato aspermy and cucumber mosaic viruses: I. Physical and chemical properties

Abstract

Some physical and chemical properties of the V strain of tomato aspermy virus (TAV) and the Q strain of cucumber mosaic virus (CMV) have been compared. The size, morphology, sedimentation rate, RNA base ratio, and buoyant density of the two viruses are indistinguishable. Preparations of RNA from both viruses were each resolved into four distinct species by polyacrylamide-gel electrophoresis. TAV-RNA preparations contained species with molecular weights of 1.26 × 10 6,1.10 × 10 6, 0.90 × 10 6, and 0.43 × 10 6 daltons, and CMV-RNA, species of 1.26 × 10 6, 1.10 × 10 6, 0.77 × 10 6, and 0.34 × 10 6 daltons. Analysis of sodium dodecyl sulphate (SDS)-treated viral proteins by polyacrylamide-gel electrophoresis showed that both viruses have protein subunits of molecular weight 24,500 daltons. The amino acid compositions of proteins from the two viruses, although similar, were distinguishable, and the calculated molecular weights of protein subunits were 26,100 and 26,300 daltons for TAV and CMV, respectively. The two viruses were serologically distinct. On the data presented it is suggested that in preparations of both TAV and CMV three distinct particles are present in each with identical protein shells, but different RNA cores.