Effect of Phosphate and Borate on the Infectivity of some Viruses during Purification

Abstract

IN a method¹ developed in 1958 for purifying cucumber mosaic virus, infected tissue was homogenized in 0.5 M potassium phosphate buffer containing 0.1 per cent thio-glycollic acid. To chelate possible metal contaminants in the phosphate, 0.001 M sodium EDTA was also added before the thioglycollie acid in subsequent tests. The nitrate was clarified by adding n-butanol (to an 8.5 per cent final concentration) and this was followed by low-speed centrifugation (30 min at 8,000 r.p.m. in the No. 30 rotor of a Spinco model L ultracentrifuge). The virus in the resultant supernatant was pelleted by ultracentrifugation (60 min at 30,000 r.p.m. in the No. 30 rotor), the virus pellets resuspended in 0.05 M phosphate buffer (pH 7.5) and the suspension finally clarified by low-speed centrifugation.