Short description of experiments and analyses: The formation of nitric oxide (NO) was examined in live hemocyte cells and gill filaments of the bivalve Arctica islandica at different partial pressures of oxygen (pO2; measurements conducted with ISO-NOP electrode & confocal microscopy). To establish whether cellular NO formation of A. islandica is catalyzed enzymatically, NO production was measured in the presence and absence of the nitric oxide synthase inhibitor (L-NAME). In a second set of experiments, the effect of chemically (by spremineNONOate) produced NO on gill respiration and cytochrome-c-oxidase activity was examined during phased reduction of pO2 (16 kPa-2 kPa; measurements conducted with oxygen meter & spectrophotometer). Further, nitrite and nitrate contents were determined in the hemolymph of bivalves after 3.5 days of exposure to normoxic, hypoxic, and anoxic conditions (measurements conducted with microplate reader).
Funding
The cooperative project between the Alfred Wegener Institute and the University of Bremen was financed by the German Science foundation (DFG), grant numbers AB124/10-1 and DR262/10-1.