In vitro propagation of Amyloodinium ocellatum for immunologic and therapeutic studies of amyloodiniosis in red drum (Sciaenops ocellatus)

Amyloodinium ocellatum (Brown, 1931) is a cosmopolitan dinoflagellate ectoparasite of warm water marine and euryhaline fish causing severe economic loss to the mariculture industry. The 3 stage life cycle of A. ocellatum has made this parasite difficult to study under controlled laboratory conditions and resistant to most chemotherapeutics. The studies in this dissertation describe techniques that ameliorate obstacles to the study of this organism, evaluate therapeutic measures for, and characterize red drum (Sciaenops ocellatus) immunity to dinospores of A. ocellatum.; A method for collecting microbe-free A. ocellatum tomonts was developed. The sterile dinospores produced were subsequently used to develop an in vitro propagation protocol. This protocol was then used to evaluate a bioremediation (brine shrimp) and a chemotherapeutic (lasalocid) measure for amyloodiniosis. Brine shrimp (Artemia salina) and lasalocid reduced the level of A. ocellatum infection under laboratory conditions.; The red drum immunoglobulin was isolated and characterized by a combination of size exclusion, anion exchange, and agarose gel chromatography with sodium dodecyl sulfate polyacrylamide gel electrophoresis. In marked contrast to previous characterizations of teleost immunoglobulin, the red drum was found to have pentameric, tetrameric, trimeric, and dimeric immunoglobulins. A red drum antiserum was produced in a rabbit (Oryctolagus cuniculus) using these immunoglobulins for use in a Western blot.; Sterile tomonts and the dinospores were used to investigate the red drum immune response to amyloodiniosis. Three groups of red drum were subjected to different dinospore treatments to assess their immune response by Western blot. The first group was injected with live dinospores, the second with cold killed dinospores, and the third group was exposed to live dinospores in the water column. Dinospores fractionated into flagella, cell wall, and soluble proteins were used as the antigen in a Western blot analysis of the red drum immune response. The red drum injected with live dinospores mounted an immune response to the flagella protein fraction but no other fraction or treatment elicited a response. These results indicate that further studies for the future development of immunoprophylaxis should be directed toward the trophont or possibly the tomont stage.