title: Effect of fetal bovine serum glycoproteins on the in vitro proliferation of the oyster parasite Perkinsus marinus: development of a fully defined medium.
abstract: The oyster parasite Perkinsus marinus replicates in our medium consisting of Dulbecco modified Eagle's medium: Ham's F12 nutrient mixture (1:1) supplemented with 1-5% fetal bovine serum, with a doubling time of 24 hours during the exponential phase of the culture. Fetal bovine serum concentrations above 5% dramatically reduced parasite proliferation in a dose-dependent manner. We tested the individual effects of the three major protein components of fetal bovine serum (fetuin, transferrin and albumin) on the replication of the parasite in a serum-free medium. At the concentrations tested, fetuin enhanced parasite growth, whereas albumin had a modest positive effect and transferrin was inhibitory. Proteolytic digestion of fetuin, strongly diminished its growth-enhancing properties, indicating that the overall glycoprotein architecture may be required for activity. On the contrary, desialylation of fetuin slightly enhanced its growth-promoting activity. The addition of fetuin at 1.7 mg/ml to the serum-free DME:Ham's F12 medium yielded growth rates that are comparable to those obtained with our standard culture methodology. This has resulted in a fully defined culture medium that will allow for a rigorous characterization of excretory/secretory products involved in modulating or blocking the host's humoral and cellular defense mechanisms.
mesh_terms: D000818:Animals; D016782:Apicomplexa / Q000187:drug effects / Q000254:growth & development* / Q000302:isolation & purification; D002417:Cattle; D003470:Culture Media; D016895:Culture Media, Serum-Free; D005312:Fetal Blood; D005333:Fetus; D006023:Glycoproteins / Q000097:blood* / Q000494:pharmacology*; D007700:Kinetics; D010125:Ostreidae / Q000469:parasitology*
chemical_list: D003470:Culture Media; D016895:Culture Media, Serum-Free; D006023:Glycoproteins