DEVELOPMENT OF A PROTEIN-FREE CHEMICALLY-DEFINED CULTURE-MEDIUM FOR THE PROPAGATION OF THE OYSTER PATHOGEN PERKINSUS-MARINUS

In the present study we describe a protein-free, chemically defined cu lture medium, designated JL-ODRP-3, which supports the propagation oi Perkinsus marinus, a parasite of the eastern oyster, Crassotrea virgin ica. P. marinus adapted rapidly to the defined medium and the growth r ate of the protozoan increased significantly following a few subcultur es. Two isolates oi P. marinus, one from the Chesapeake Bay (Virginia) and the other from;he Gulf of Mexico (Texas) were cultured for al lea st ten passes. The doubling times far the isolates from Virginia and T exas, in Jog phase, were 18 +/- 1.2 and 28.6 +/- 3.2 hours respectivel y, after ten passes in JL-ODRP-3. Moreover, P. marinus cells cultured in the defined medium were infective to eastern oysters. Finally, the defined medium was used successfully to initiate continuous cultures o f P. marinus from heart fragments of infected oysters. The absence oi proteins and peptides from this chemically defined medium demarcates J L-ODRP-3 as the most suitable medium to study P. marinus proteins, to produce antigens far antibody production, and to screen chemotherapeut ic agents.