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ANTIOXIDANT ENZYMES, POTENTIAL VIRULENT FACTORS, IN DIFFERENT STRAINS OF THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS
Chu, F., A. K. Volety, AND S. Armknecht. ANTIOXIDANT ENZYMES, POTENTIAL VIRULENT FACTORS, IN DIFFERENT STRAINS OF THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS. Presented at International Conference on Shellfish Restoration, Hilton Head Island, SC, November 18 - 21, 1998.
The oyster protozoan parasite, Perkinsus marinus, is one of the two important parasites causing severe mortality in the eastern oysters (Crassostrea virginica) on the US east coast. Our recent study suggests that P. marinus cells and its extracellular products (ECP) could scavenge the reactive oxygen intermediates produced by oyster hemocytes or inhibit their production. The parasites' acid phosphatase (AP), superoxide dismutase (SOD), and other antioxidant enzymes are believed to play a role in scavenging or inhibiting hosts' respiratory burst. Recent studies also suggest that the virulence of P. marinus vary with strains. The extra- and intra-cellular activities of AP, SOD, catalase, and glutathione peroxidase (GP) were examined in six different P. marinus strains/isolates, i.e., Delaware Bay, New Jersey (DB-NJ), Mobjack Bay, Virginia (MB-VA), Barataria Bay, Louisiana (BB-LA), Laguna Madre, Texas (LM-TX), Oxford, Maryland (OX-MD), and York River, Virginia (YR-VA). It was found that no calatase or GP was detected in P. marinus and its ECP. The YR-VA strain has significantly higher extracellular AP activities (units/mg cell protein) than all other strains. Intracellular AP activity was low (1.0 unit/mg total cell protein) in all strains. LM-TX strain had the greatest intracellular AP activity. The mean SOD activity (ng SOD/mg total cell protein) was higher in the YR-VA strain, but statistically insignificant from the other strains. SOD activity was detected only in the culture media of 97, and 114 days old P. marinus culture. Results will be reported and discussed in relation to the virulence of this parasite.