Characterization of the Nervous Necrosis Virus Quasispecies Property in Orange-spotted Grouper (Epinephelus coioides)

• Main Authors: Chor-SiongTan, 陳祖淞
• Other Authors: Tzong-Yueh Tan
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/45683165067641017138

碩士 === 國立成功大學 === 生物科技研究所碩博士班 === 100 === In grouper cultivation industry, nervous necrosis virus (NNV) infection had cause serious lose for the grouper cultivation industry. However, some of the NNV infected fishes were found survive and become a healthy NNV carrier grouper. This could be most probable due to virus quasispecies characteristic. Therefore, I would like to investigate the influence of different quasispecies of NNV coat protein (CP) on diverse aspects of nodavirus-induced pathogenesis. The chromatograph from the direct sequencing result shows that the NNV isolated from healthy NNV carrier showed more than one NNV variant present in the host. Next, series passage of NNV in grouper fin-1 (GF-1) cells also confirmed NNV quasispecies phenomena. Six CP expression plasmids from different NNV quasispecies variants were constructed. From the transient expression of CP in GF-1, it was found that QS3 and QS4 have a higher localization ratio of CP in nucleolus. Next, the result of cell cycle by using flow analysis shown that the proportion of GF-1 cells arrested in G2 transfected with pZsYellow1-N1/CP was slightly higher than that of cells transfected with blank plasmid, especially for nodavirus QS2 and QS5 CP. Next, we found that different nodavirus genotype NNV quasispecies CP downregulated the tumor necrosis factor (TNF) promoter activity especially QS2, QS3 and QS4 CP. Overall, the study represents a first comprehensive analysis of the pathogenesis of different nodavirus quasispecies CP of nodavirus.