Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Changes in the maximal activities of key enzymes can be one mechanism of adaptation to severe stress, such as oxygen deprivation. To assess the influence of this mechanism on anoxia survival by the freshwater crayfish, Orconectes virilis, the maximal activities of 19 enzymes of intermediary metabolism were assayed in tail muscle and hepatopancreas of control and 20 hour anoxia exposed animals. In hepatopancreas, most of the anoxia-induced significant changes to maximal activities were increases, including increases in activities of glucokinase (2.3-fold), aldolase (1.6-fold), lactate dehydrogenase (1.3-fold), glucose-6-phosphate dehydrogenase (3.3-fold), branched chain alpha-ketoacid dehydrogenase (87%), fructose-1,6-bisphosphatase (43%) and serine dehydratase (53%). In hepatopancreas, the metabolic rate potential of both phosphofructokinase and pyruvate kinase activities dropped significantly, down by 53 and 28 %. Most of the significant changes in enzyme activities in tail muscle were decreases (for example, citrate lyase and malic enzyme decreased by 59 and 21 %, respectively) with the notable exception of hexokinase activity which rose 2.7-fold in anoxic muscle. These enzymatic changes could determine the extent to which key metabolic pathways are adjusted as part of the overall metabolic rate depression of the anoxic state.

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Poster Number PAcowan0410
Keywords: metabolic, arrest, crustacean, anaerobiosis, glycolysis