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Metabolic responses to cold in subterranean crustaceans
Julien Issartel1, David Renault, Yann Voituron
1Ecologie des Hydrosystèmes Fluviaux, UMR CNRS 5023, Université Lyon 1, 69622 Villeurbanne Cedex, France. julien.issartel@univ-lyon1.fr
The Journal of Experimental Biology
|July 27, 2005
Summary
Cold-hardy crustaceans like Niphargus rhenorhodanensis accumulate more free amino acids (FAA) and trehalose. These metabolic changes correlate with their enhanced cold tolerance, unlike related species.
Area of Science:
- * Environmental Physiology
- * Crustacean Biology
- * Biochemistry
Background:
- * Subterranean (hypogean) and surface-dwelling (epigean) crustaceans exhibit varying cold tolerances.
- * Metabolic adjustments, including polyol, sugar, and free amino acid (FAA) accumulation, are key to surviving cold temperatures in ectotherms.
- * Understanding these biochemical strategies is crucial for predicting species' responses to environmental changes.
Purpose of the Study:
- * To investigate the changes in polyol, sugar, and FAA body content in two hypogean crustaceans (Niphargus rhenorhodanensis, Niphargus virei) and one epigean crustacean (Gammarus fossarum) under cold acclimation.
- * To correlate these metabolic changes with the known cold tolerances of the studied species.
- * To explore the potential biogeographical influences on cold hardiness in subterranean crustaceans.
Main Methods:
- * Acclimation of crustaceans (N. rhenorhodanensis, N. virei, G. fossarum) to controlled temperatures: 12°C, 3°C, and -2°C.
- * Quantification of polyol, sugar (trehalose), and free amino acid (FAA) body content.
- * Comparative analysis of metabolic data with previously established cold survival times (Lt50).
Main Results:
- * Gammarus fossarum significantly increased alanine and glutamine at lower temperatures, with trehalose rising only at -2°C.
- * Niphargus virei showed moderate increases in alanine and glycine, with no significant trehalose change.
- * Niphargus rhenorhodanensis exhibited the most pronounced response, with significant increases in total FAA (alanine, glycine, arginine, glutamine) and a gradual rise in trehalose with decreasing temperature, correlating with its superior cold tolerance.
Conclusions:
- * Crustacean levels of FAA and trehalose are directly correlated with their cold tolerance, with N. rhenorhodanensis showing the highest levels and tolerance.
- * Metabolic responses to cold vary significantly, even between hypogean species living in similar environments.
- * The exceptional cold hardiness of N. rhenorhodanensis may be linked to its biogeographical history during Quaternary glaciations.