tailieunhanh - Báo cáo y học: " Molecular characterization of porcine circovirus 2 isolated from diseased pigs co-infected with porcine reproductive and respiratory syndrome virus"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Molecular characterization of porcine circovirus 2 isolated from diseased pigs co-infected with porcine reproductive and respiratory syndrome virus | Yi and Liu Virology Journal 2010 7 286 http content 7 1 286 VIROLOGY JOURNAL STUDY PROTOCOL Open Access Molecular characterization of porcine circovirus 2 isolated from diseased pigs co-infected with porcine reproductive and respiratory syndrome virus Jianzhong Yi Chengqian Liu Abstract In this study we isolated a porcine circovirus 2 PCV2 strain from piglets co-infected with porcine reproductive and respiratory syndrome virus PRRSV . The complete genome of this strain was sequenced phylogenetic and polymorphic analyses were carried out. BLAST searches revealed the highest sequence identity nt and aa to Guangxi strain EF675230. The phylogenetic tree showed that clustering of the isolates didn t strongly correlate to geographical distribution. Polymorphic analyses demonstrated that the amino acids at most of the polymorphic sites in Open Reading Frame 1 ORF1 and 2 ORF2 belong to the same amino acid group according to chemical or structural properties and revealed that highly polymorphic regions overlapped with the known immunoreactive epitopes of ORF2. 1 Introduction Postweaning multisystemic wasting syndrome PMWS characterized by growth retardation paleness of the skin dyspnea and increased mortality rates 1 2 was first described in Canada in 1991 and is now widespread throughout swine production areas of the world 3 4 . The genome of PCV is a single-stranded circular DNA of about kb. ORF1 encodes the Rep proteins involved in virus replication and is highly conserved among isolates 5 . ORF2 encodes a 234 amino acid aa Cap protein which is the main structural protein and also the major antigen inducing neutralizing immune responses 6 . The ORF3 protein is involved in PCV2-induced apoptosis by the caspase-8 and caspase-3 pathways 7 . However healthy pigs experimentally inoculated with PCV2 developed only mild clinical symptoms 8 9 suggesting that other concomitant factors may be needed for the development of typical clinical PMWS 10 .