碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 100 / Two iridoviruses, grouper iridovirus of Taiwan (TGIV) of genus Megalocytivirus and grouper iridovirus (GIV) of genus Ranavirus, have caused serious epidemics in several maricultured fish species in Taiwan. In this study, we used de novo transcriptome analysis and Digital Gene Expression (DGE) technology to investigate the gene expression profile changes in orange-spotted grouper (Epinephelus coioides) spleens after TGIV and GIV infections, separately. After DGE, the differentially expressed genes were identified using a 4-fold-change cutoff. Two hundred and four genes were found to be up-regulated in the spleen from TGIV-infected grouper, and 713 genes were down-regulated; in GIV-infected spleen, 641 genes were up-regulated and 829 down-regulated. Five genes, including hemoglobin subunit -2 (Hb), CC motif chemokine 19 precursor (CCL pre-19), Toll-like receptor 9 isoform A, B (TLR9-A, B) and Mx, were selected for further study. QPCR was performed to analyze their expressions in both spleen and headkidney from iridoviruse-infected groupers and from groupers that had been vaccinated and then was challenged with iridoviruses. At 3 days post-infection (dpi), the expression of Hb gene was induced in TGIV-infected but not in GIV-infected headkidney; vaccination delayed the induced expression of Hb in TGIV. CCL pre-19 had similar expression patterns between TGIV- and GIV-infected spleens: up-regulated at 1 dpi and down-regulated thereafter; in headkidney, TGIV induced CCL pre-19 expression at 3 dpi. Vaccination decreased the induced expression of CCL pre-19. For TLR9-A and B, after viral infections, the induced expression levels in spleen were higher than that in headkidney; after vaccination, the expression levels in viral-infected groupers were lower than that in uninfected grouper. Both viruses could induce Mx gene expression; after vaccination, the expression levels in TGIV-infected grouper at 3 dpi were significantly higher than that in GIV-infected grouper. Based on our results, we concluded that: differential expression levels of Hb gene might be related to anoxia and splenomegaly; CCL pre-19 regulated the immediate immune responses to viral infections; vaccination could reduce the induced expression levels of TLR9-A and B genes; different expression patterns of Mx gene between TGIV- and GIV-infected groupers suggested that distinct signal pathways are involved. These results could help us to have better understanding of the host–pathogen interactions in E. coioides, and to the development of control strategies against iridoviruses infection.
| Identifer | oai:union.ndltd.org:TW/100NTOU5086103 |
| Date | January 2012 |
| Creators | Ming-Hung Wu, 吳明鴻 |
| Contributors | Hsin-Yin Chou, 周信佑 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 99 |
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