RESUMEN
The interaction of ultraviolet radiation and virus particles of Western Equine Encephalomyelitis Virus (WEE) and Newcastle Disease Virus (NDV) which have respectively RNA of positive (RNA+) and negative (RNA-) polarity as genomes, was studied using purified particles. The purified virus preparations were irradiated at a range from 1,000 to 6,000 joules per m2 with posterior analysis of their propagation in primary cell cultures of chicken embryos. It could be observed that a radiation dose of to 4,500 joules per m2 could induce 10(9) TCID50 per ml as minimal loss of titer for WEE virus and NDV. The hemagglutination assay was used as a toll to evaluate the alterations caused by UV radiation on the molecular arrangement of virus proteins. Alterations of the virus hemagglutinating activity were only observe when radiation levels higher than 6,000 joules per m2 were used. The results from hemolysis assays showed the importance of the loss of the envelope integrity and the damages to nucleoprotein structures during the inactivation process, when we used radiation doses higher than 6,000 joules per m2. This model of study can increase our comprehension of the radiation effects on the cell physiology and biological components of the cell membranes.
Asunto(s)
ARN/efectos de la radiación , Rayos Ultravioleta/efectos adversos , Virus de la Enfermedad de Newcastle/efectos de la radiación , Virus de la Encefalitis Equina del Oeste/efectos de la radiación , Hemaglutinación , Pruebas de Hemaglutinación , Hemólisis , Proteínas Virales/efectos de la radiación , Virus de la Enfermedad de Newcastle/aislamiento & purificación , Virus de la Encefalitis Equina del Oeste/aislamiento & purificaciónRESUMEN
Venezuelan equine encephalomyelitis virus labelled with [14C]aminoacids or [3H]uridine was purified and UV-irradiated. The irradiation led to the formation of uracil photodimers and the covalent linking of the nucleocapsid protein C to virion RNA. The inactivation of infectivity correlated with the formation of uracil dimers, whereas the RNA-protein links were formed at much higher doses of UV irradiation. The analysis of covalent RNA-protein complexes suggests that a fairly large fraction (at least one third) of the whole content of C protein is able to participate in the formation of UV-induced links, suggesting extensive contacts of RNA with protein with the nucleocapsid.
Asunto(s)
Virus de la Encefalitis Equina Venezolana/efectos de la radiación , Activación Viral/efectos de la radiación , Animales , Centrifugación por Gradiente de Densidad , Embrión de Pollo , Virus de la Encefalitis Equina Venezolana/genética , Virus de la Encefalitis Equina Venezolana/aislamiento & purificación , Fibroblastos , Dímeros de Pirimidina/química , Dímeros de Pirimidina/efectos de la radiación , ARN Viral/química , ARN Viral/efectos de la radiación , Rayos Ultravioleta , Proteínas Virales/química , Proteínas Virales/efectos de la radiaciónRESUMEN
Formation of Venecuelan equine encephalomyelitis virus (VEE) aggregates induced by UV-light has been studied. The high doses of UV-irradiation induced the protein-protein cross-links resulting in formation of fast sedimenting viral structures. The latter structures are supposed to be presented by the aggregates of several virions linked by the UV-light induced RNA-protein and protein-protein covalent bonds. The lesions in the fine structure of virion envelope was registered by the electron microscopy technique.