OBSERVATION ON NEGATIVELY STAINED TOBACCO RINGSPOT VIRUS AND ITS 2 RNA-DEFICIENT COMPONENTS

Unpenetrated, partly penetrated, penetrated, and disrupted particles were observed in preparations of tobacco ringspot virus and its two RNA-deficient components after negative staining with either phosphotungstic acid (PTA) or uranyl acetate (UAc). The proportion of particles penetrated by PTA increased with increasing pH of the stain, but time of staining had no effect. RNA-containing particles were positively stained after long periods in UAc, followed by thorough washing. These observations show that unpenetrated particles observed in PTA stained preparations of TRSV do not necessarily represent particles devoid of RNA. © 1969.