Use of Potassium Tartrate for Equilibrium Density-gradient Centrifugation of Animal Viruses

Abstract

DENSITY-GRADIENT centrifugation of both the velocity and equilibrium types has been applied for separating and purifying plant viruses such as tobacco mosaic and potato yellows¹, and also very recently to animal viruses such as Rous sarcoma², Shope fibroma³ and polyoma⁴. Equilibrium banding with satisfactory recovery of biological activity has usually been achieved in rubidium or cæsium chlorides after centrifugation for approximately 24 hr. Some viruses are, however, inactivated by these salts, and others, as, for example, Rous sarcoma, require stabilization by albumin and citrate². Non-equilibrium sedimentation in glycerol gradients has been used to purify Shope papilloma³ ; and reasonably sharp peaks of influenza and Newcastle disease viruses, and also of vaccinia hæmagglutinin, may be obtained after brief centrifugation in sucrose gradients of the velocity-sedimentation type⁵.