碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 93 / In recent years, infectious diseases caused by iridoviruses have resulted in heavy losses to many marine species such as grouper. This study examined numerous ill fish likely infected with iridoviruses. Iridoviruses were identified by PCR amplification in the giant sea perch from I-lan, cobia from Ping-tung and giant grouper from Tainan. The grouper brain (GB) cell line was then used to isolate the viruses. The viruses were temporarily named giant sea perch iridovirus-like virus (PILV), cobia iridovirus-like virus (CILV) and giant grouper iridovirus-like virus (GGILV) These three isolated viruses were compared with the Grouper Iridovirus of Taiwan (TGIV) and Red Sea Bream Iridovirus (RSIV).
In studying susceptibility of cell lines to viruses, the TGIV, RSIV, PILV, CILV and GGILV were inoculated into SB cells (grouper swim bladder cells), GB cells (grouper brain cells), GF cells (grouper fin cell) and BF-2 cells (blue-gills fish fin cells). The susceptibilities of each cell line to viruses differed. The TGIV had a cytopathic effect (CPE) on all cells, and GGILV was only in part identified in CPE on SB and GF cell lines. The RSIV had a CPE on the BF-2 cell line. No CPE on BF-2 cell was observed. Extensive CPE by PILV and CILV infection was observed in GF cells.
The ultrastructure of virus-infected cells displayed many icosahedra virion in TGIV, RSIV and CILV infected cells. Many viruses appeared in the cytoplasm of TGIV and CILV infected cells; mean diameters of the viral particles were 175–186 nm. Few viral paricles were located outside the lysed cells, of which virus sizes were consistently 188±14 nm.
For PCR detection of virus, two primer sets were employed: primers to TGIV and RSIV. Experimental results showed that the (F1R3) primer to TGIV did not detect the CILV and only one set of the RSIV primer amplified CILV DNA. One set of RSIV primer did no detect the TGIV and another set did not detect the GGILV. The PCR results identified the homologous in PILV and RSIV. Sequencing data for PCR products successfully separated the five viruses into at least three genotypes. One genotype comprised RSIV, PILV and GGILV and not TGIV and CILV.
Immunofluorescent staining of RSIV M10 monoclonal antibody identified the strong signal on RSIV positive control and no signals on other virus isolates. Pathogenical examination of the five viruses to grouper was conducted by intraperitoneal injection. Cumulative mortalities of the TGIV injected fish reached 85% within 14 days and accounted for the highest mortality rate. Mortalities of RSIV, PILV, CILV and GGILV were 60%, 60%, 45% and 65%, respectively. Results of this study demonstrate the lethality to grouper for the five iridoviruses.
| Identifer | oai:union.ndltd.org:TW/093NTOU5086050 |
| Date | January 2005 |
| Creators | Shu-Chin Lai, 賴書瑾 |
| Contributors | 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 | 78 |
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