SEROLOGICAL AND PHYSICAL PROPERTIES OF SOME STONE-FRUIT VIRUSES: NON-VIRUS PARTICLES ASSOCIATED WITH INFECTION

Abstract

Cherry yellow virus, isolates Y.2 and Y.4, and necrotic ring spot virus, isolates N.4 and N.5, purified either from cucumber leaves or from sour cherry petals, were characterized by antigenically related particles that sedimented at approximately 72 S. Some preparations of each virus derived from either host also contained either a 35 S or a 22 S component usually having a low nucleic acid content. Such preparations were shown by the agar gel double-diffusion technique to contain two antigens, V and Q, that were only distantly, if at all, related. The 72 S component is associated with the V antigen, whereas the 22 S and 35 S components are tentatively considered to be two forms of the Q antigen. The Q antigen could also be detected in clarified expressed sap of infected cucumber tissue, but not in that of healthy cucumber nor in extracts prepared from healthy sources by methods used to purify the viruses. The Q antigen is thus associated with infection, but its origin has not yet been satisfactorily determined.