The purification and properties of chornic bee-paralysis virus.

Summary Purified preparations of chronic bee-paralysis virus were obtained by clarifying water extracts of paralysed bees with ether and carbon tetrachloride; the virus particles were concentrated from the clarified extracts either by centrifugation or precipitation with ammonium sulphate. The preparations contained particles of three sizes, all approximately 220 A wide and ellipsoidal in outline, but about 410, 540 or 640 A long with sedimentation coefficients (S 20, w) of 97, 110 and 125 respectively. The shortest particles contained least nucleic acid, and preparations containing mostly short particles were less infective than those containing mostly long ones. The particles contained ribose nucleic acid with a molar base ratio of G 20%—A24%—C28%—U28%. When incubated in cold acid or alkali solutions (1 n), the virus particles formed empty rounded protein shells.