RESUMO
The cytology of nine isolates of cauliflower mosaic virus was compared by light and electron microscopy. Differences noted among the isolates were: the size of cytoplasmic inclusion bodies, frequency of virions occurring free in the cytoplasm as opposed to those in inclusions, the ratio of virions to the amount of matrix protein in inclusions, and intraplastidial inclusions induced by one of the isolates. It was concluded that these four cytological features are expressions of the viral genome rather than the host. One of the isolates induced different sized inclusions in two different hosts.
RESUMO
In an attempt to isolate new gene products of cauliflower mosaic virus a procedure was developed for isolation of the cytoplasmic inclusion bodies induced by the virus. Two types of inclusions, the relative ratios of which vary with virus strain, were obtained. One type was the native, vacuolated inclusion encountered in sections of tissue observed with the electron microscope. It contains virus particles. A second, granular type of inclusion body is devoid of virus. It consists wholly of electron-dense material that resembles the matrix material of the native inclusion body. Granular inclusions consist of a single 55,000-dalton protein which is also a major constituent of the native vacuolated type. This protein is not antigenically related to the virus.
Assuntos
Cloroplastos/microbiologia , Corpos de Inclusão Viral , Nicotiana/microbiologia , Plantas Tóxicas , Vírus do Mosaico do Tabaco , Fracionamento Celular , Citoplasma/microbiologia , Microscopia Eletrônica , Doenças das Plantas , Protoplastos/microbiologia , Vírus do Mosaico do Tabaco/crescimento & desenvolvimento , Vírus do Mosaico do Tabaco/ultraestruturaRESUMO
A Gram-positive, rod-shaped bacterium was isolated and grown in pure culture on artificial mediums from the leafhopper Draeculacephala minerva Ball which had fed on plants infected with Pierce's disease. The bacterial culture was injected into uncontaminated leafhoppers which were than allowed to feed on healthy grapevines. After exposure to these leafhoppers, typical symptoms of Pierce's disease developed; however, no symptoms developed on plants exposed to leafhoppers injected with sterile culture medium. The same organism was reisolated from the experimentally inoculated plants. Electron microscopic examination of these infected plants revealed bacterial cells localized in the xylem tissues. No such cells were seen in healthy or control plants.
