METABOLIC RESPONSE IN ARENICOLA-MARINA TO LIMITING OXYGEN AS REFLECTED IN THE H-1-NMR OXYMYOGLOBIN SIGNAL

Many intertidal animals can endure prolonged periods of environmental stress and have developed strategies to preserve a functioning energy state in the cell. Recent H-1/P-31-NMR techniques have allowed investi gators to monitor directly mammalian tissue metabolism in vivo. In par ticular, the signals of myoglobin (Mb) offer a unique opportunity to e xplore the intracellular oxygen-partial-pressure [p(O-2)] interaction in Arenicola marina, a standard model to study hypoxia tolerance in in vertebrates. The present study reveals that the H-1-NMR MbO(2) signal at -2.9 ppm is detectable in tissue and reflects directly the oxygenat ed state. As the p(O-2) declines, MbO(2) saturation and oxygen consump tion decrease. However, phosphotaurocyamine concentration remains unal tered until the MbO(2) saturation falls below 33%. The extracellular t o intracellular p(O-2) gradient appears substantial. The study establi shes the H-1-NMR technique as an approach to measure the intracellular p(O-2) with an oxygenated state marker and presents the interrelation ship between oxygen and the metabolic adaptation during hypoxic stress .