Abstract

Recently described disease-related problems among tropical corals and other anthozoan species have raised concerns about the health of coral reef ecosystems on a global scale. While a few diseases affecting these organisms are well described with an identified etiologic agent, others remain rather ill defined. Cell culture methodology, an important tool in veterinary pathology for both vertebrates and invertebrates, is particularly valuable in disease research involving viral and toxicological agents. Successful cell culture methods and continuous cell lines are not well established for cnidarian species, including corals and other reef inhabitants. This technology would provide valuable tools for the investigation of some of the more nebulous disease syndromes affecting corals. Recent research efforts at the National Fish Health Research Laboratory have been directed towards improving our understanding of coral diseases. Among these efforts, we have been attempting to develop cell culture methods suitable for the in vitro growth of cnidarian cells.

Preliminary cell culture trials have utilized various scyphozoan species, including sea nettles (Chrysaora quinquecirrha), moon jellyfish (Aurelia aurita), and mangrove upside-down jellyfish (Casseopea xamachana). A variety of tissue dissociation methods, culture media formulations, and culture conditions have been evaluated. To date, the most successful methods we have attempted involved mechanical dissociation of sea nettle tissues focusing predominantly on the subumbrellar region and the use of culture media containing 75% sea nettle mesogleal extract and 25% commercially prepared tissue culture media supplemented with antibiotics. Using these methods, sea nettle amoebocytes, undifferentiated amoeboid cells, have been maintained in culture over many weeks, able to withstand several cell passages. Ongoing and future work will examine the longevity of these cells in culture, their response to environmental variables and toxicity testing, and their response to cryogenic preservation to evaluate their usefulness as a laboratory tool. In addition, these cell culture methods will be used for similar experiments with anthozoan organisms including sea anemones and species of stony corals and octocorals.