Purification and Western-blot assay of the capsid protein of the red-spotted grouper nodavirus

Red-spotted grouper nodavirus Dayawan isolate(RG-CN)was purifed by differential centrifugation, sucrose density gradient centrifugation(10%~40%, W/V) and CsCl isopyknical density centrifugation(30%~40%, W/W).The results showed that the viral particles exhibited a buoyant density of 1.3102~1.3243 g·cm^-3. By Western-blot assay, viral capsid protein showed two polypeptides with molecular weights of 37 and 31 kDa, mainly being 31 kDa.