Study On Comparative Genomics Of Functional Genes In Different Virulence Strains Of Orf Virus(ORFV)

Contagious ecthyma is known as sore mouth. This disease is caused by sheep contagious pustular virus which is a zoonotic infectious diseases.The orf virus (ORFV) is a representative member of the Parapoxvirus genus of the poxvirus family,and has a distinct and unique features.Other members of the same genus are bovine papular stomatitis (BPS) virus, parapoxvirus of red deer in New Zealand (PVNZ), pseudocowpox virus (PCPV) as well as three tentative species of the genus, auzdyk disease virus, chamois contagious ecthyma and seal pox virus.At present, Contagious ecthyma is found worldwide and the incidence increased year by year which has brought sheep a certain degree of loss to sheep husbandry.The infection of the disease is mainly through the injury of skin and mucous membrane, sheep, goats and other animals and people come on an acute and highly contact sexually transmitted the diseases can caused an acute and highly Contact infectious disease.Virions are cocoon shaped with about250-280nm in length and170-200nm in width and was linear ds DNA.In addition to the elliptical particles shape, there are also have conical, brick shape and special thread sample spherical particles.The surface of Virus particles consists of the rope sample structure arrangement which wrapped around the long axis of virus particles with8shape, but there are also other winding method.To date,there are134gene that ORFV encode.Following ORFV infection, the host’s immune systemwill respond to eliminate the invaders and, as a firststep, initiates an innate response to the virus. Thisinvolves the induction of chemokines and cytokines by various cells of the innate immune system. ORFV infection leads to an accumulation of natural killer (NK) cells, neutrophils and dendritic cells (DCs) at the site of infection. In addition, ORFV induces the release of interferon-a (IFN-a), interleukin-1β (IL-lb), IL-8, granulocyte macrophage colony-stimulating factor (GM-CSF) and IFN-y. The fact that inactivated ORFValso leads to, from a qualitative perspective, a dominant Thl-typeImmune response in various species suggests that this response is elicited by the viral particle itself.The ORFV genome encodes for a variety of immunomodulatory proteins These include a viral orthologue of IL-10, as well as orthologues of the mammalian vascular endothelial growth factor (VEGF) and of the vaccinia E3L gene that encodes an IFN resistance factor. In addition, a protein that binds and inhibits GM-CSF and IL-2(GM-CSF/IL-2inhibitory factor; GIF)has been described.function genes of ORFV have been identified, but the research on its virulence factor is not particularly clear which play an important role in virus infected host.So the study on virulence genes in sheep aphtha variation of different virulence strains, will help proved its molecular variation and the relationship between the pathogenicity.Based on this, this experiment were studied as follows:1. The separation and identification of Contagious ecthyma sheep aphtha viru in hubei provinceFrom the scab of the sick sheep, one strain of virus was isolated using MDBK cell; According to the published Chemokine-binding Protein (CBP) gene sequence of ORFV in the GenBank, Primer5biological software was adopted to design a pair of specific primers,and PCR amplification CBP genes, the separation of virus was applied to the animal regression test. The results of animal inoculation showed that:The MDBK cells appeared evident pathological changes after they were inoculated with ORF virus three to four days.The characteristic pathological changes of cells is gathered, swelling, fusion, interstitial broadening.The efraction sexual was enhancement until fall off.A pair of primers were designed, which were directed to the gene code for CBP. The amplified DNA fragment was in accordance with the expected length of843bp.The clinical model was successfully reproduce through animal experiments which prove that rabbit, sheep and other animals has highly pathogenic.2.Sequence Analysis of part function gene of different virus virulence strains.After the vaccine strain strong strain and extend the attenuated strain infected host cell,functional genes were identifyed by PCR technology. Six functional genes were successfully amplified which from three different virulence ORFV strains.The differences of homologous function gene were spotted, target segments and analyzes its corresponding relations.From genomics level system, the study of weak sheep aphtha virus strain can accumulated data about attenuated molecular mechanism.