Cell Cultures and Reverse Transcriptase Activity From a Tumor of a Moray Eel

Abstract

This work arose from observations of scientists at SeaWorld, Orlando, of nodular, granulomatous tumor-like skin lesions on a number of captive green moray eels Gymnothorax funebris), as well as eels freshly caught from the reef areas around the Florida coast. Homogenates of the lesions were capable of passing the disease when injected into green morays and other anguilliformes. Cultures of tumor-derived and normal moray eel cells were derived and have been continually passaged for more than a year. Stable expression of reverse transcriptase activity was detected in conditioned culture medium from the tumor-derived cells, with no activity detected in controls. Assays of extracts from frozen tissue samples taken at the time of culture initiation showed concentration dependent activity in the tumor, with little or no activity in extracts of ovary, liver and head kidney from the same animal. Conditioned medium from the tumor cells was centrifuged at 27,000 X g (2 hr), and reverse transcriptase activity was found in the pelleted material. When this material was transferred to a 25%–50% sucrose gradient and centrifuged, particles banded at a density of 1.17–1.19 g/ml.