Effects of Triclosan on the Oyster Parasite, Perkinsus marinus and Its Host, the Eastern Oyster, Crassostrea virginica

Abstract

Because temperature plays an important role on progression and transmission of disease caused by Perkinsus marinus in the field, the effects of triclosan on the viability of P. marinus meronts (trophozoites) and oyster hemocytes were tested at a range of environmental relevant temperatures. Additionally, we examined the triclosan effect on reactive oxidative intermediate production (ROI) by oyster hemocytes and tested the efficacy of treating infected oysters with triclosan in eliminating/ reducing P. marinus infection in a pilot experiment. When P. marinus cultivated at 13°C, 20°C, and 28°C was exposed to triclosan at corresponding temperatures, 2-10 mM triclosan killed 10-30% at 20°C and $40% at 28°C, but #10% at 13°C. When exposure of P. marinus cultivated at 28°C to triclosan at 26°C, similar mortality was noted as those recorded at 28°C. Treating hemocytes from oysters maintained at 13°C, 20°C, or 26°C with 2, 5, 10 mM triclosan at corresponding temperatures, killed 2% to 13% at 13°C and 6 to16% at 20°C. No mortality occurred in hemocytes exposed to 2-10 mM triclosan at 26°C. However, at the highest temperature and triclosan concentration tested (28°C, 10 mM triclosan), hemocyte mortality exceed 30%. Exposure of hemocytes to triclosan concentrations of 2-10 mM for 4 h at 4°C significantly reduced the ROI production in hemocytes in a dose-dependent response. Treating P. marinus infected oysters with 300 and 600 mg triclosan/oyster daily for 8 wk, significantly slowed the disease progression.

Immunotoxic effects of triclosan in the clam Ruditapes philippinarum

“…For example, in vitro exposure of hemocytes to various TCS concentrations (2-100 lM) significantly reduces cell viability in the oyster Crassostrea virginica at the two highest tested concentrations (50-100 lM) (Lund et al 2005). In the same species, exposure of hemocytes to TCS concentrations ranging from 2 to 10 lM for 4 h at 4°C significantly reduces the production of reactive oxygen intermediates (ROI) in hemocytes in a dose-dependent manner (Chu et al 2008). Possible genotoxic and cytotoxic effects of TCS have been investigated in hemocytes of the freshwater mussel Dreissena polymorpha (Binelli et al 2009a).…”

A Review of Current State of Knowledge Concerning Perkinsus marinus Effects on Crassostrea virginica (Gmelin) (the Eastern Oyster)

“…However, treatment with quinine, triclosan, and other chemotherapeutics has been shown to be effective in a laboratory setting. 9,32 Various organizations, both governmental and industrial, have promoted the possible introduction of a nonnative oyster species into the US eastern and southern coastal waters in the hope that a new oyster species could take the place of C. virginica. Examples are Ostrea edulis (the European flat oyster), C. gigas (the Pacific oyster), and, most recently, Crassostrea ariakensis (the Suminoe oyster).…”

“…However, treatment with quinine, triclosan, and other chemotherapeutics has been shown to be effective in a laboratory setting. 9,32…”

Anti Perkinsus olseni Monoclonal Antibody Generation Using Hypnospores as Antigens

“…Polyclonal antibodies (pAbs) were produced from P. marinus hypnospores from infected oysters (Crassostrea virginica). Both pAbs and mAbs specific for P. marinus were produced from the same oyster species [16,17]. For mAb production, mice were immunized with trophozoites or a complex set of extracellular products to produce mAbs specific for P .…”