Ultracentrifugal Concentration of a Homogeneous Heavy Component from Tissues Diseased with Equine Encephalomyelitis

Abstract

With the demonstration of the existence of a heavy protein in plant tissues diseased with tobacco mosaic virus1 it became inevitable that similar proteins should be sought in other kinds of virus-infected tissues. Most viruses are more or less unstable towards the chemicals which would naturally be used in efforts to concentrate and purify them. The air-ultracentrifuge2 has, however, furnished a new tool3 which has been successful in extracting and purifying several of the less stable virus proteins causing plant diseases4 and in preparing a similar substance5 from virus-induced rabbit papillomas (Shope). The same type of ultracentrifugal examination has now been made of tissues diseased with the virus of equine encephalomyelitis.∗As in the previous ultracentrifugal concentrations an angle-centrifuged tissue suspension was ultracentrifuged for one to one and a half hours in a maximum field of ca 50,000 times gravity. All but a trace of the virus activity was thus sedimented. The translucent pellet formed ...