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Susceptibilities of medaka (Oryzias latipes) cell lines to a betanodavirus.

Adachi K, Sumiyoshi K, Ariyasu R, Yamashita K, Zenke K, Okinaka Y - Virol. J. (2010)

Bottom Line: Although the viral coat protein was detected in all the cell lines inoculated, the levels of cytopathic effect development and viral propagation were quite different among the cell lines.Those levels were especially high in OLHNI-1 and OLHNI-2 cells, but were extremely low in OLME-104 cells.Some cell lines entered into antiviral state after RGNNV infections probably because of inducing an antiviral system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-hiroshima 739-8528, Japan.

ABSTRACT

Background: Betanodaviruses, members of the family Nodaviridae, have bipartite, positive-sense RNA genomes and are the causal agents of viral nervous necrosis in many marine fish species. Recently, the viruses were shown to infect a few freshwater fish species including a model fish medaka (Oryzias latipes). Although virological study using cultured medaka cells would provide a lot of insight into virus-fish interactions in molecular aspects, no such cells have yet been tested for virus susceptibility.

Results: We tested ten medaka cell lines for susceptibilities to redspotted grouper nervous necrosis virus (RGNNV). Although the viral coat protein was detected in all the cell lines inoculated, the levels of cytopathic effect development and viral propagation were quite different among the cell lines. Those levels were especially high in OLHNI-1 and OLHNI-2 cells, but were extremely low in OLME-104 cells. Some cell lines entered into antiviral state after RGNNV infections probably because of inducing an antiviral system. This is the first report to examine the susceptibilities of cultured medaka cells against a virus.

Conclusion: OLHNI-1 and OLHNI-2 cells are candidates of new standard cells for betanodavirus study because of their high susceptibilities to the virus and their several advantages as model fish cells.

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CPE development in RGNNV-infected medaka cells. The cells (1.0-1.5 × 105) were inoculated with RGNNV of the indicated titers and cultured at 30°C. Cell morphology of the RGNNV-inoculated or mock-inoculated cells was observed at 1-3 dpi for OLHNI-2 cells and at 3-7 dpi for OLCAB-e31 and OLME-104 cells.
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Figure 2: CPE development in RGNNV-infected medaka cells. The cells (1.0-1.5 × 105) were inoculated with RGNNV of the indicated titers and cultured at 30°C. Cell morphology of the RGNNV-inoculated or mock-inoculated cells was observed at 1-3 dpi for OLHNI-2 cells and at 3-7 dpi for OLCAB-e31 and OLME-104 cells.

Mentions: We firstly examined the infectivity of RGNNV against the medaka cell lines (Table 1) by detecting CP-expressing cells at 1 day post-inoculation (dpi). When the cells were inoculated with RGNNV having the 50% tissue culture infectious dose (TCID50) of 106, most of the inoculated cells expressed the CP in OLHNI-1, OLHNI-2, and OLKaga-e1 cells (Figure 1). In contrast, quite a small number of cells expressed the CP in OLF-136 and OLME-104 cells (Figure 1). The typical CPE, represented as rounded cells which were finally detached from the dish, was detected only in OLHNI-1 and OLHNI-2 cells at 1 dpi of 105 or 106 TCID50 of RGNNV (data not shown). To examine further whether the eight cell lines other than OLHNI-1 and OLHNI-2 cells exhibit CPE by RGNNV-inoculations, inoculated cells were incubated for up to 7 days and observed under a microscope (Figure 2). OLHNI-2 cells showed the apparent CPE at 2 dpi when the cells were exposed to 103 TCID50 of RGNNV and almost detached from the dish at 3 dpi (Figure 2). OLHNI-1, OLHE-131, OLKaga-e1, and OLHdrR-e3 cells also showed apparent CPE in 4-5 days after inoculated with 103 TCID50 of virus (data not shown). In contrast, no apparent CPE was observed in OLCAB-e31, OLME-104, OLCAB-e21, or OLF-136 cells (Figure 2, data not shown for the latter two) within 7 days even though the cells were exposed to 106 TCID50 of virus. These results indicate that OLHNI-1 and OLHNI-2 cells are highly susceptible to RGNNV compared with the other cell lines. Furthermore, RGNNV production and/or spread seem to be restricted in some of the medaka cell lines though the virus can multiply in all of the cell lines to a varying degree.


Susceptibilities of medaka (Oryzias latipes) cell lines to a betanodavirus.

Adachi K, Sumiyoshi K, Ariyasu R, Yamashita K, Zenke K, Okinaka Y - Virol. J. (2010)

CPE development in RGNNV-infected medaka cells. The cells (1.0-1.5 × 105) were inoculated with RGNNV of the indicated titers and cultured at 30°C. Cell morphology of the RGNNV-inoculated or mock-inoculated cells was observed at 1-3 dpi for OLHNI-2 cells and at 3-7 dpi for OLCAB-e31 and OLME-104 cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2908575&req=5

Figure 2: CPE development in RGNNV-infected medaka cells. The cells (1.0-1.5 × 105) were inoculated with RGNNV of the indicated titers and cultured at 30°C. Cell morphology of the RGNNV-inoculated or mock-inoculated cells was observed at 1-3 dpi for OLHNI-2 cells and at 3-7 dpi for OLCAB-e31 and OLME-104 cells.
Mentions: We firstly examined the infectivity of RGNNV against the medaka cell lines (Table 1) by detecting CP-expressing cells at 1 day post-inoculation (dpi). When the cells were inoculated with RGNNV having the 50% tissue culture infectious dose (TCID50) of 106, most of the inoculated cells expressed the CP in OLHNI-1, OLHNI-2, and OLKaga-e1 cells (Figure 1). In contrast, quite a small number of cells expressed the CP in OLF-136 and OLME-104 cells (Figure 1). The typical CPE, represented as rounded cells which were finally detached from the dish, was detected only in OLHNI-1 and OLHNI-2 cells at 1 dpi of 105 or 106 TCID50 of RGNNV (data not shown). To examine further whether the eight cell lines other than OLHNI-1 and OLHNI-2 cells exhibit CPE by RGNNV-inoculations, inoculated cells were incubated for up to 7 days and observed under a microscope (Figure 2). OLHNI-2 cells showed the apparent CPE at 2 dpi when the cells were exposed to 103 TCID50 of RGNNV and almost detached from the dish at 3 dpi (Figure 2). OLHNI-1, OLHE-131, OLKaga-e1, and OLHdrR-e3 cells also showed apparent CPE in 4-5 days after inoculated with 103 TCID50 of virus (data not shown). In contrast, no apparent CPE was observed in OLCAB-e31, OLME-104, OLCAB-e21, or OLF-136 cells (Figure 2, data not shown for the latter two) within 7 days even though the cells were exposed to 106 TCID50 of virus. These results indicate that OLHNI-1 and OLHNI-2 cells are highly susceptible to RGNNV compared with the other cell lines. Furthermore, RGNNV production and/or spread seem to be restricted in some of the medaka cell lines though the virus can multiply in all of the cell lines to a varying degree.

Bottom Line: Although the viral coat protein was detected in all the cell lines inoculated, the levels of cytopathic effect development and viral propagation were quite different among the cell lines.Those levels were especially high in OLHNI-1 and OLHNI-2 cells, but were extremely low in OLME-104 cells.Some cell lines entered into antiviral state after RGNNV infections probably because of inducing an antiviral system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Graduate School of Biosphere Science, Hiroshima University, Higashi-hiroshima 739-8528, Japan.

ABSTRACT

Background: Betanodaviruses, members of the family Nodaviridae, have bipartite, positive-sense RNA genomes and are the causal agents of viral nervous necrosis in many marine fish species. Recently, the viruses were shown to infect a few freshwater fish species including a model fish medaka (Oryzias latipes). Although virological study using cultured medaka cells would provide a lot of insight into virus-fish interactions in molecular aspects, no such cells have yet been tested for virus susceptibility.

Results: We tested ten medaka cell lines for susceptibilities to redspotted grouper nervous necrosis virus (RGNNV). Although the viral coat protein was detected in all the cell lines inoculated, the levels of cytopathic effect development and viral propagation were quite different among the cell lines. Those levels were especially high in OLHNI-1 and OLHNI-2 cells, but were extremely low in OLME-104 cells. Some cell lines entered into antiviral state after RGNNV infections probably because of inducing an antiviral system. This is the first report to examine the susceptibilities of cultured medaka cells against a virus.

Conclusion: OLHNI-1 and OLHNI-2 cells are candidates of new standard cells for betanodavirus study because of their high susceptibilities to the virus and their several advantages as model fish cells.

Show MeSH
Related in: MedlinePlus