| The lung samples were collected from a pig farm of Xinjiang suffered from the swine high fever. Thesuspected porcine reproductive and respiratory syndrome virus (PRRSV) were isolated in the monkey kidneycells (Marc-145). The ideification, cloning, and gene analysis of the suspected PRRSV were performed inthis study.The collected lung tissue was inoculated in a monolayer of Marc-145cells. The typical cytopathic effect(CPE) was found in the cultured Marc-145cells at the third blind passages. The specific primers weredesigned and a430bp gene fragme was amplified by RT-PCR. The results of gene sequencing and geneanalysis were shown the isolated virus was PRRSV(Blue ear disease)and named Xinjiang XJ-Q strain. Thehalf cell culture infectious dose (TCID50) for XJ-Q was10-5.5/0.1mL at the fourth passages. The virusparticle about50nm was seen on electron microscopy.Two pairs of specific primers PN1/PN2and PO1/P02were designed according to published sequencesof Nsp2and ORF5for PRRSV, and the sequences of Nsp2and ORF5for XJ-Q strain were amplified byRT-PCR. The two fragmes of769bp and603bp were found for Nsp2gene and ORF5gene of XJ-Q strain,respectively. The amplified products were cloned to PUCm-T plasmid vector. The positive clones wereideified by PCR, enzyme digestion and sequencing.The results of gene sequening were shown the similarity of Nsp2gene for the XJ-Q strain was75.8%~92.4%and47.7%, whereas similarity of ORF5gene for the XJ-Q strain was88.1%~96.4%and62.4%, respectively, comparied with those of the American(VR-2332) and European(LV) strains, indicatingthe XJ-Q strain belonged to American ones. A phylogenetic tree was generated base on ORF5sequences ofXJ-Q strain, HK13and HB-1were ranged in a same branch, indicating XJ-Q strain and HB-1strain were inthe same subgroup and. The sequnences of XJ-Q from Xinjiang showed drversity on amino acidsassociated with virulence of PRRSV by comparison of the deduced amino acids of ORF5gene. |
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