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Cytology and Histology

Carnation Etched Ring Virus Inclusions: Serology and Ultrastructure of Alkaline-Treated Inclusions. Roger H. Lawson, Research plant pathologist, Agricultural Research, Science and Education Administration, U. S. Department of Agriculture, Beltsville, MD 20705; Suzanne S. Hearon, Research plant pathologist, Agricultural Research, Science and Education Administration, U. S. Department of Agriculture, Beltsville, MD 20705. Phytopathology 70:327-332. Accepted for publication 21 September 1979. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/Phyto-70-327.

Carnation etched ring virus (CERV) cytoplasmic inclusion bodies induced the formation of antibodies in immunized rabbits to intact virions (S-Ag) and to two rapid-diffusing antigens. One of the rapid-diffusing antigens (R-AG) may be matrix protein. The second rapid-diffusing antigen was absorbed by sap from healthy Saponaria vaccaria. The effects of extraction medium, cations, and pH on the stability of CERV inclusions were determined by serological tests and electron microscopy. Agar gel double diffusion tests and electron microscopy showed that R-Ag was dispersed more readily from inclusions extracted in distilled water than from those extracted in Tris buffer. Increased amounts of R-Ag were released from inclusions treated in distilled water at increasingly alkaline pH. Inclusions in distilled water showed a progressive increase in the loss of dense-staining matrix protein in ultrathin section with increasing pH. In Tris buffer at high pH the inclusion matrix remained more electron-dense than in distilled water. Weak precipitin lines were formed to R-Ag in Tris. S-Ag was detected with prolonged incubation in both distilled water and Tris at neutral and alkaline pH. The addition of cations stabilized the matrix protein. R-Ag was detected when protoinclusions were first observed in infected S. vaccaria cells.