- Volume 21, Issue 2, 1973

Lipids extracted from extensively purified iridescent viruses (types 2 and 6) have been analysed by thin-layer chromatography. The lipid forms 9% by weight of the iridescent virus particle and is equivalent to 59 × 106 daltons per particle. Negatively stained preparations and thin sections of the virus particles viewed with the electron microscope indicated that a membrane is located internally. There is sufficient lipid in the virus particles to form a continuous lipid bilayer at this internal site.

The infection of MDBK cells by bovine syncytial virus did not result in the formation of syncytia. Plaques of infected cells were dispersed into single cells and quantitative studies were made on the conditions which influenced the spread of the virus. The stimulation of cell metabolism greatly enhanced the spread of virus, which was inhibited by bromodeoxyuridine.

Examination of Navarro, Kwatta,and Mossuril viruses by electron microscopy revealed typical rhabdovirus morphology. They are longer than most other rhabdoviruses. All three viruses were observed in sections of infected mouse brain while Navarro and Kwatta viruses were also observed in infected Vero cells. The three viruses were unrelated antigenically to each other and to other rhabdoviruses of animals.

Some but not all of the mouse L cell strains carry virus particles which have been found to be morphologically, biochemically and antigenically indistinguishable from known RNA tumour viruses. Present electron microscopic study has revealed that cultures of two of the clones derived from NCTN 929 cells when grown in Eagle’s medium enriched with foetal calf serum contained a few intracisternal A-type virus-like particles but were continuously negative for C-type virus particles. Exposure of the cultures to the drug cytochalasin B resulted in the appearance of abundant intracytoplasmic and extracellular C-type virus particles. Possible mechanisms of the activation of virus synthesis and release by cytochalasin B are discussed.