The Open Zoology Journal

2009, 2 : 15-23
Published online 2009 March 13. DOI: 10.2174/1874336601002009015
Publisher ID: TOZJ-2-15

Oxygenogenesis, a Defence Mechanism of the Newt for Surviving Anoxic Stress

Giuliano Frangioni , Giancarlo Fuzz , Alessandro Gremignani , Stefano Bianchi and Gianfranco Borgioli
Department of Animal Biology and Genetics, University of Florence, via Romana 17, 50125 Florence, Italy.

ABSTRACT

At 8°C specimens of Triturus carnifex, isolated in a respiratory chamber containing water with 1.3 ppm of oxygen, completely consumed it in little over an hour; yet, even after 48 hours of anoxia, the oxygen pressure in blood sampled from the arterial cone never fell below 30% of that recorded in normoxic controls. The permanence of oxygen in the blood, incompatible with the condition of anoxia, demonstrates that there must be a physiological mechanism that produces the molecule. The liver, on account of its mass and histological structure, is the only possible seat of this process. With the supplement of anaerobic glycolysis, the oxygen produced allows the animal to survive for long periods in totally anoxic environments, a phenomenon already observed in other lower vertebrates but until now explained by glycolysis alone. Further experimental data indicate that haemolysis and hepatic melanogenesis are essential in promoting and inactivating oxygenogenesis respectively.

Keywords:

Anoxia, liver, snails, melanin, newt, respiration.