Purification and Some Properties of Two Viruses Infecting the Cultivated Mushroom Agaricus bisporus

Highly purified preparations of the isometric mushroom viruses 1 and 4 were made by a combination of differential centrifugation, ion-exchange chromatography on DEAE-cellulose and sucrose density-gradient centrifugation. Purified preparations of MV1 virions (25 nm diam.) sedimented at 130S contained one capsid polypeptide of mol. wt. 24400 and two species of double-stranded RNA of mol. wt. approx. 1.4 x 10⁶. MV4 particles (35 nm diam.) had a sedimentation value of 140 to 145S, contained one capsid polypeptide of mol. wt. 63800 and two species of dsRNA of mol. wt. 1.5 x 10⁶ and 1.4 x 10⁶. MV1 and MV4 were antigenically unrelated.