Aggregation of Purified Tobacco Mosaic Virus

Abstract

THE point of view has been advanced by Bawden and Pirie¹ that purified tobacco mosaic virus consists of stable aggregates of many smaller units present in the infectious tissue extracts. Such aggregation has been stated to take place after purification by chemical means or after high-speed centrifugation, and to result in a decrease in specific activity, in an increase in stream double refraction, and in an inability of the purified virus to pass ultra-filters which readily permit of the passage of crude virus. Similar conclusions have been drawn for purified latent mosaic virus1. It was early recognized that prolonged chemical treatment of tobacco mosaic virus with salts at room temperature resulted in a decrease in specific activity². Later, other evidence was secured indicating that aggregation of virus occurred as a result of such treatment ; hence there is complete agreement that the rather drastic chemical procedures used by Stanley³ and by Bawden and Pirie1 and others for the purification of tobacco and latent mosaic viruses and their strains resulted in aggregation.