The effects of hypoxia and pH on phenoloxidase activity in the Atlantic blue crab, Callinectes sapidus

摘要: In its natural coastal and estuarine environments, the blue crab, Callinectes sapidus, often encounters hypoxia, accompanied by hypercapnia (increased CO2) an associated decrease in water pH. Previous studies have shown that exposure to hypercapnic hypoxia (HH) impairs crab's ability remove culturable bacteria from hemolymph. present study we demonstrate activity of phenoloxidase (PO), enzyme critical antibacterial immune defense crustaceans, is decreased at low levels hemolymph O2 pH occur tissues crabs exposed HH. Hemocyte PO was measured tissue normoxic (5% 15% O2, approximate venous arterial hemolymph, respectively) hypoxic (1% O2) compared air-saturated conditions (21% O2). 33%, 49% 70% air 15%, 5% 1% respectively. When held 21% lowered within physiological limits, with pH, showing a 16% reduction 7.0 as 7.8. These results suggest compromises crustaceans HH defend themselves against microbial pathogens.