Purification and electron microscopy of carnation mottle virus

Abstract

Abstract Carnation mottle virus was purified by differential centrifugation. Sap was extracted from frozen leaves and clarified by heating at 55°c for 5 min, by the addition of 8 per cent n-butanol or by adjusting the pH to 4.8. Loss of virus occurred with heat clarification, although this method, with the addition of 8 per cent butanol followed by resuspension of virus in 0.05 M (pH 7) phosphate buffer after centrifugation, removed contaminating host materials. Carnation mottle virus sedimented as a single band in sucrose and potassium tartrate density-gradient columns, but usually 2 bands occurred in cesium chloride gradients. There was no evidence for a nucleic acid-free “top component” III the virus preparations. The sedimentation coefficient of the virus was 104S. Two or 3 precipitation lines occurred in gel-diffusion precipitin tests with virus and anti-serum. The virus was examined in the electron microscope by the metal-shadowing and negative-staining methods. The particles were about 330 A in dia...