HA Gene Variation Analysis of H9N2 Sub-type Avian Influenza Virus from Three Strains in Different Times

HA Gene of H9N2 sub-type avian influenza virus from three strains in different times was amplified, purified and then sequenced. The results of its sequence analysis showed that the whole length of the amplified HA Gene was 1 683 bp, encoding 560 amino acids. The amino acid sequence of three virulent strains at cleavage site was R-S-S-R, which was low-pathogenicity strain. According to the amino acid sequence of the isolated strains, there were 7 potential glycosylation sites, and the receptor-binding site was the specific sequence of the avian-derived influenza virus. Amino acids on the left edge of receptor-binding site were all NGQQG, while amino acids on the right edge of receptor-binding site were GTSKA. From the comparative sequence analysis of HA Gene from some referenced strains, the results indicated that nucleotide and amino acid homology between isolated strains and referenced strains was higher. Evolutionary tree analysis showed that three strains were all Eurasian species, and there was a close relationship with the representative strains of A / duck / Hong Kong/Y280/97.

Cloning,Sequencing of F and HN Genes and Molecular Characteristics of Goose Paramyxovirus BZ02 Isolate

[Objective] The aim of this study was to clone and sequence F and HN genes of the isolated goose paramyxovirus and thus further investigate on its pathogenesis and evolutionary origins. [Method] According to the published F and HN gene sequences of Avian Paramyxovirus TypeⅠat home and abroad, two pairs of primers (FF, FR; HNF, HNR) were designed by DNAstar software, and F and HN genes were also amplified by PCR. The PCR products were recovered and ligated to T vector, while the positive clones were identified by ampicillin plate screening and PCR. After bacteria shaking, the plasmid was extracted and sent to Shanghai Sangon for sequencing. The sequences were compared with the sequences in GenBank, and the phylogenetic tree was drawn by DNAstar software. Meanwhile, the phylogenetic analysis of amino acid residues was also studied. [Result] The ORF of F gene was 1 662 bp encoding 553 amino acids, and its cleavage site was 112R-R-Q-K-R-F117, which was consistent with the characteristics of virulent strains. 101-bit and 121-bit amino acid residues were K (Lys) and D (Asp). The ORF of HN gene was 1 716 bp encoding 571 amino acids. The homology of HN sequence in 29 strains of goose paramyxovirus to YG97 was the highest, accounting for 99.6%. Analysis of glycosylation sites revealed that glycosylation site of BZ02 strain at 538-540aa disappeared. The phylogenetic tree drawn by HN genes was highly consistent with that drawn by F genes. Compared with the homology of F and HN nucleotide sequence of the published type-Ⅰgoose paramyxovirus in China, BZ02, JG97, HG97 and YG97 were divided into the same sub-group, and the nucleotide and amino acid sequences homologies were highest between BZ02 and YG97 strain. [Conclusion] BZ02, JG97, HG97 and YG97 have the same evolutionary origin or all originate from YG97.

Detection of Serum Antibodies of Porcine Pseudorabies Virus(PRV)in Binzhou City in 2014

To understand immunization effect of pseudorabies vaccine and infection status of porcine pseudorabies( PR) in pig farms and guide prevention and control against PR,453 copies of blood samples collected from 43 different scale pig farms in four counties( districts) of Binzhou City were detected with ELISA to investigate PRV g B antibody and g E antibody. Detection results showed that the g B antibody positive rate of sows was 75. 58%,and that of fattening pigs was68. 67%; the pig farms with positive rate higher than 70% accounted for 74. 42% of total survey pig farms. The PRV g E antibody positive rates of sows and fattening pigs were 25. 41% and 26. 67%,and the positive rates of pig farms were 46. 51% and 44. 33%,respectively. There were regional differences among counties( districts).