Meeting Abstract
Hypoxia is typically a potent inhibitor of vertebrate development and even brief exposures can lead to abnormal development or death. Embryos of the annual killifish Austrofundulus limnaeus can develop normally across the entire spectrum of oxygen availability. As oxygen partial pressures are reduced, the rate of development is reduced until levels reach near anoxic, at which point development is arrested and embryos enter into a state of reversible quiescence. The level of hypoxia required to arrest development is extremely low during early development and increases during late development. In fact, the rate of early development through somitogenesis appears to be independent of oxygen partial pressure. As embryos develop, they transition from oxyconformers into oxyregulators at about the onset of organogenesis. Further, the critical partial pressure of oxygen required to alter metabolic rate decreases as embryos develop. It appears that a unique set of mitochondrial traits and the ability to accumulate gamma-aminobutyric acid are critical for supporting survival and normal development under extreme oxygen limitation in this species.
