RESUMO
The method of electron paramagnetic resonance and spin labels was used to study the structural characteristics of Venezuelan equine encephalomyelitis virus envelope and cell membranes of chick embryo fibroblasts. The virus envelope lipids form a bilayer structural typical of biological membranes. The lipid bilayer of virions is more rigid than the cytoplasmic membrane of chick embryo fibroblasts. Investigation of interaction of a small hydrophilic molecule with Venezuelan equine encephalomyelitis virus particles showed free water to be absent in the virions. A structural translation was detected at 25 degrees-30 degrees C in the virion membrane. The role of membrane structures in virus reproduction is discussed.
Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Vírus da Encefalite Equina Venezuelana/análise , Vírion/análise , Fenômenos Químicos , Físico-Química , Marcadores de Spin , Cultura de VírusRESUMO
The studies showed that the effect of cycloheximide on reproduction of the virus of Venezuelan equine encephalitis (VEE) depended on the time of the antibiotic administration. When the antibiotic was added 3--5 hours after the inoculation (after formation of the virus RNA-polymerase), accumulation of virus RNA and 60--100 S virus structures was observed in the cells, while virus nucleotides and infection virus did not practically form. The 60--100 S structures included the cell proteins. They were resistant to EDTA and their swimming density in cesium chloride was 1.3--1.4 gm/cm3, it was characteristic of RNA of a non-ribosomic nature. According to these properties 60--100 S structures may be classified as belonging to the "hybrid" RNA analogous to the RNA complexes of VEE virus with the cell proteins. Probably addition of cycloheximide provided conditions in the infected cells for increase of the "hybrid", structural pool since the synthesis of the structural virus proteins was suppressed.
Assuntos
Cicloeximida/farmacologia , Vírus da Encefalite Equina Venezuelana/efeitos dos fármacos , RNA Viral/biossíntese , Radioisótopos de Carbono , Centrifugação com Gradiente de Concentração , Vírus da Encefalite Equina Venezuelana/ultraestrutura , Biossíntese de Proteínas/efeitos dos fármacos , Fatores de Tempo , Transcrição Gênica/efeitos dos fármacos , Trítio , Cultura de Vírus , Replicação Viral/efeitos dos fármacosRESUMO
A comparative study of the reproduction of an alphavirus. Venezuelan equine encephalomyelitis virus (VEE), in chick embryo fibroblasts (CEF) and oncornavirus type D (OV-D) produced spontaneously by human continuous cells (HEp-2) was carried out. The differential index of reproduction of both viruses was the yield of RNA-containing virus structures released from the cells. For VEE this index increased in the course of infection 100-150-fold. For OV-D the index changed little during long-term cultivation of the cells and was only 0.2%--1%. The effect of inhibitors, ethidium bromide and cycloheximide, on the RNA synthesis and production of virus structures was studied. Ethidium bromide was shown to inhibit reproduction of both the viruses considerably, whereas the effect of cyclohemimide on them was dissimilar: its effect on VEE virus depended on the time of its addition, while OV-D virus production did not depend on the time of its addition and was even stimulated in the presence of cycloheximide.
Assuntos
Arbovírus/fisiologia , Células Cultivadas/metabolismo , Vírus da Encefalite Equina Venezuelana/fisiologia , Retroviridae/fisiologia , Animais , Antivirais , Arbovírus/efeitos dos fármacos , Linhagem Celular , Embrião de Galinha , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Vírus da Encefalite Equina Venezuelana/efeitos dos fármacos , Etídio/farmacologia , Humanos , RNA/biossíntese , RNA Viral/biossíntese , Retroviridae/efeitos dos fármacos , Cultura de Vírus , Replicação ViralRESUMO
The results of the study of host antigens in Venezuelan equine encephalomyelitis virus by means of neutralization test in tissue culture using sera containing antibody for the species-specific antigens, Forssman antigen and group A and B antigens are presented. They show the inhibiting effect of the sera to be not uniform. The greatest neutralizing effect on the virus was exerted by immune sera to chick embryo fibroblasts and their fractions (by 0.5-3.9 lg PFU/ML). The lack of the virus neutralizing effect in sera for the Forssman antigen and for group A antigen appears to depend upon their deeper localization in the structure of virion.