title: Effects of triclosan on growth, viability and fatty acid synthesis of the oyster protozoan parasite Perkinsus marinus.
abstract: Perkinsus marinus, a protozoan parasite of the Eastern oyster Crassostrea virginica, has severely impacted oyster populations from the Mid-Atlantic region to the Gulf of Mexico coast of North America for more than 30 yr. Although a chemotherapeutic treatment to reduce or eliminate P. marinus from infected oysters would be useful for research and hatchery operations, an effective and practical drug treatment does not currently exist. In this study, the antimicrobial drug triclosan 5-chloro-2-(2,4 dichlorophenoxy) phenol, a specific inhibitor of Fab1 (enoyl-acyl-carrier-protein reductase), an enzyme in the Type II class of fatty acid synthetases, was tested for its effects on viability, proliferation and fatty acid synthesis of in vitro-cultured P. marinus meronts. Treatment of P. marinus meront cell cultures with concentrations of > or = 2 microM triclosan at 28 degrees C (a temperature favorable for parasite proliferation) for up to 6 d stopped proliferation of the parasite. Treatment at > or = 5 microM at 28 degrees C greatly reduced the viability and fatty acid synthesis of meront cells. Oyster hemocytes treated with > or = 20 microM triclosan exhibited no significant (p < 0.05) reduction in viability relative to controls for up to 24 h at 13 degrees C. P. marinus meronts exposed to > or = 2 microM triclosan for 24 h at 13 degrees C exhibited significantly (p < 0.05) lower viability relative to controls. Exposure of P. marinus meronts to triclosan concentrations of > or = 20 microM resulted in > 50% mortality of P. marinus cells after 24 h. These results suggest that triclosan may be effective in treating P. marinus-infected oysters.
authors.affiliation: Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, Virginia 23062, USA.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Lund
authors.forename: Philippe
authors.initials: P
authors.lastname: Soudant
authors.forename: Fu-Lin E
authors.initials: FL
authors.lastname: Chu
authors.forename: Ellen
authors.initials: E
authors.lastname: Harvey
authors.forename: Stephanie
authors.initials: S
authors.lastname: Bolton
authors.forename: Adolph
authors.initials: A
authors.lastname: Flowers
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004305:Dose-Response Relationship, Drug; D056890:Eukaryota / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000037:antagonists & inhibitors*; D005434:Flow Cytometry; D008401:Gas Chromatography-Mass Spectrometry; D006434:Hemocytes / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007928:Lethal Dose 50; D010125:Ostreidae / Q000469:parasitology*; D014260:Triclosan / Q000633:toxicity*
chemical_list: D014260:Triclosan; D064429:Fatty Acid Synthases