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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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Related in: MedlinePlus

Restriction of RGNNV spread among medaka cells. (A) The cells (1.0-1.5 × 105) were inoculated with 106 TCID50 of RGNNV and cultured at 30°C. The CP and cell nucleus in the infected cells were detected by indirect immunofluorescence assay and DAPI staining, respectively, at the indicated period. Data represents the merged image of Alexa488-fluorescence and DAPI staining. (B) Rates for the infected cells against the total cells represented in Figures 1 and 3A were calculated and shown periodically.
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Figure 3: Restriction of RGNNV spread among medaka cells. (A) The cells (1.0-1.5 × 105) were inoculated with 106 TCID50 of RGNNV and cultured at 30°C. The CP and cell nucleus in the infected cells were detected by indirect immunofluorescence assay and DAPI staining, respectively, at the indicated period. Data represents the merged image of Alexa488-fluorescence and DAPI staining. (B) Rates for the infected cells against the total cells represented in Figures 1 and 3A were calculated and shown periodically.

Mentions: To examine whether RGNNV spread occur in the medaka cell lines which lacked clear appearance of CPE (Figure 2), we examined CP-expressing cells in those cell lines inoculated with RGNNV. In OLCAB-e21 and OLCAB-e31 cells, the numbers of CP-expressing cells were decreased dramatically with time (Figure 3) compared with those at 1 dpi (Figure 1). In OLF-136 cells, the number of CP-expressing cells was increased transiently at 3 dpi (Figure 3) compared to that at 1 dpi (Figure 1) but then decreased gradually. No virus spread was observed in OLME-104 cells throughout the experimental period (Figures 1 and 3). These results indicate that the viral spread was tightly limited in the four cell lines, which resulted in the defect of apparent CPE development as shown in Figure 2.


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)

Restriction of RGNNV spread among medaka cells. (A) The cells (1.0-1.5 × 105) were inoculated with 106 TCID50 of RGNNV and cultured at 30°C. The CP and cell nucleus in the infected cells were detected by indirect immunofluorescence assay and DAPI staining, respectively, at the indicated period. Data represents the merged image of Alexa488-fluorescence and DAPI staining. (B) Rates for the infected cells against the total cells represented in Figures 1 and 3A were calculated and shown periodically.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Restriction of RGNNV spread among medaka cells. (A) The cells (1.0-1.5 × 105) were inoculated with 106 TCID50 of RGNNV and cultured at 30°C. The CP and cell nucleus in the infected cells were detected by indirect immunofluorescence assay and DAPI staining, respectively, at the indicated period. Data represents the merged image of Alexa488-fluorescence and DAPI staining. (B) Rates for the infected cells against the total cells represented in Figures 1 and 3A were calculated and shown periodically.
Mentions: To examine whether RGNNV spread occur in the medaka cell lines which lacked clear appearance of CPE (Figure 2), we examined CP-expressing cells in those cell lines inoculated with RGNNV. In OLCAB-e21 and OLCAB-e31 cells, the numbers of CP-expressing cells were decreased dramatically with time (Figure 3) compared with those at 1 dpi (Figure 1). In OLF-136 cells, the number of CP-expressing cells was increased transiently at 3 dpi (Figure 3) compared to that at 1 dpi (Figure 1) but then decreased gradually. No virus spread was observed in OLME-104 cells throughout the experimental period (Figures 1 and 3). These results indicate that the viral spread was tightly limited in the four cell lines, which resulted in the defect of apparent CPE development as shown in Figure 2.

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