Clam Virus Disease Investigation And In Vitro Cell Culture Study

Meretrix meretrix Linnaeus is an important marine product of Jiangsu sea area. But high mortalities occurred frequently in the last several years. So this study has been carried out to research the reasons of it.A spherical Virus-like Particles was detected in the specimen of Meretrix meretrix Linnaeus, which was collected from Jiangsu seacoast, in the summer of 2004 when the heavy mortalities occurred. The spherical-shaped virions with the size of 45~55nm in diameter lackd in capsula. The virus could be found in the tissues of digestive glands, intestines, mantles and gills. The infected cells with virus have obvious pathological changes. The nucleus was degenerated or deformed, parts of the cristae of mitochondria were deformed and dissolved, the endoplasmic reticulum swelled and a lot of ribosomes were detached from it, and the number of lysosomes increasing. The villi of gill cells or intestine cells desquamated, and the granules of fat or hepatin dissolved in liver cells.The mantle tissues and cells of Meretrix meretrix Linnaeus were cultured in vitro with improved Medium 199, at some different temperatures and salinities. The new cells grow out from the brink of tissues after 24 hours. 48 hours later, a layer of proliferation cells was formed around the tissues. These cells needed 7-10 days to bestrewed the bottom surface. The cell culture could last 30-35 days. Otherwise, this study described cultured cells with 3 shapes, and discussed some phenomena in tissue and cell culture at temperature 37℃.Similarly, the mantle tissues of Cristaria plicata Leach were cultured in vitro with improved Medium 199. The ultrastructure changes of the cells from cultured mantle was observed. The epithelial cells growed out foremostly, and these cells could be distinguished morphologically into two types after 2 or 3 days' culture. A little number of muscle cells could be found at the later period of culture.This study researched some conditions to form a cell line of shellfishs, and provided basical information to research diseases caused by virus on Meretrix meretrix.