No abstract

Two new cell culture systems namely epitheloid cells of Lates (LCE) and ¢broblastic cells of Lates (LCF) have been developed from fry and ¢ngerling of the economically important brackishwater ¢sh Lates calcarifer. Primary cultures were initiated by explant technique using caudal ¢n of ¢ngerling and whole body tissue of the fry. The nutritional requirements and the growth pattern in response to di¡erent culture environment were similar for the two cell cultures. The culture medium used was Leibovitz-15 supplemented with 20% fetal bovine serum (FBS) and 1% ¢sh serum. The LCE comprised of epithelioid cells and LCF cells were ¢broblastic.With a split ratio of 1:2, the con£uency of cells was attained in 8^10 days at an incubation temperature of 28 1C. The cells were found to grow well in a wide range of temperature (24^32 1C) and stable at 20 and 36 1C. The growth rate of LCFand LCE cells increased proportionately with the concentration of FBS from 5% to 20%. A decrease of serum level to 10% after eight subcultures produced no apparent change in cell morphology and growth rate. The viability of cells was found to be 70% when revived after a month of storage in liquid nitrogen ( À196 1C).

Macrobrachium rosenbergii nodavirus along with a satellite virus, extra small virus (XSV) causes white tail disease (WTD) in the giant freshwater prawn M. rosenbergii. Infected M. rosenbergii postlarvae were collected from a hatchery in Kakinada, Andhra Pradesh. The gene coding the capsid protein of XSV was cloned in a bacterial expression vector pRSET A and the recombinant protein was expressed in Escherichia coli BL21(DE3)pLysS cells. The recombinant protein was purified by Nickel affinity chromatography. Polyclonal antibodies were produced in mice against the recombinant protein and the antibodies reacted specifically with the recombinant protein and XSV in WTD-infected tissues. This is the first report of detection of XSV using antibodies against recombinant capsid protein.