Synergistic effect of acidification and hypoxia: in vivo 31P-NMR and respirometric study in fishes.

We used 31P nuclear magnetic resonance (31P-NMR) spectroscopy to measure intracellular pH (pHi) and high-energy phosphate levels of white muscle of the fish tilapia (Oreochromis mossambicus) during exposure to the stressors hypoxia and water acidification separately and simultaneously. The protocol for the graded hypoxia load was 100, 40, 30, 20, 10, 5, and 3% air saturation for 1 h at each level. For environmental acidosis the pH of the water was lowered from 7.

Fish muscle energy metabolism measured during hypoxia and recovery: an in vivo 31P-NMR study.

Three fish species were exposed to graded hypoxia levels and allowed to recover. Levels of high-energy phosphate compounds in epaxial white muscle were monitored by in vivo 31P nuclear magnetic resonance (NMR) spectroscopy. Furthermore, O2 consumption of the animals was measured.

Reversed-phase ion-paired HPLC of purine nucleotides from skeletal muscle, heart and brain of the goldfish, Carassius auratus L.--II. Influence of environmental anoxia on metabolite levels.

1. The type and the amounts of some (di)nucleotides in white skeletal muscle, heart and brain of anoxic goldfish were established with a reversed-phase ion-paired HPLC method. 2.

Reversed-phase ion-paired HPLC of purine nucleotides from skeletal muscle, heart and brain of the goldfish, Carassius auratus L.--I. Development of the analytical method.

1. A reversed-phase ion-paired liquid chromatographic (HPLC) method was developed to measure AMP, ADP, ATP, IMP, NAD+ and NADP+ levels in white muscle, heart and brain of anoxic goldfish. 2.

Direct observation of the phosphate acceptor and phosphagen pool sizes in vivo.

Earthworms were subjected to environmental anoxia (200 min) and electrical stimulation (5 min, 6 V, 50 Hz). The levels of high-energy phosphate compounds and the intracellular pH were monitored during anoxia, muscular contraction, and recovery by in vivo phosphorus-31 nuclear magnetic resonance (31P-NMR). Several key metabolites were determined by enzymatic analysis and reversed-phase high-performance liquid chromatography of perchlorate extracts.