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Adaptation of the Oxygen Transport System to Hypoxia in the Blue Crab, Callinectes sapidus

CHARLOTTE P. MANGUM
DOI: http://dx.doi.org/10.1093/icb/37.6.604 604-611 First published online: 1 December 1997

Abstract

Among the oxygen carrying proteins, two groups are known to adapt to environmental challenges in the adult stage. Both vertebrate hemoglobins and arthropod hemocyanins adapt to chronic hypoxia by responding to the actions of allosteric co-factors. The design strategy, however, differs fundamentally in the two groups. Even within the arthropods, chelicerate and crustacean hemocyanins respond to co-factors very differently. Only in the crustaceans does the oxygen carrier adapt by shifts in intrinsic molecular properties. In hypoxic blue crabs, increases in the ratio of the primitive 1 × 6-meric oligomer bring about a higher oxygen affinity relative to that in normoxic animals, in which greater proportions of the derived 2 × 6-meric oligomer are responsible for a lower oxygen affinity