1. A physiological mechanism responsible for increasing the freezing tolerance of the bivalve Modiolus demissus (Dillwyn) following low-temperature acclimation was demonstrated.
2. The rates of oxygen consumption of M. demissus acclimated to temperatures between 0 and 24 °C were presented as an Arrhenius plot. A change in slope occurred at 10 °C, suggesting that temperature alone was not responsible for the increased decline in the rate of oxygen consumption below 10 °C.
3. Low-temperature acclimation had no effect on blood Na+ or K+ concentrations but did reduce the concentration of blood Mg2+ and, in addition, resulted in the accumulation of end-products characteristic of anaerobic metabolism - tissue alanine and proline, and blood Ca2+. Furthermore, maintenance of M. demissus under anaerobic conditions increased freezing tolerance.
4. Taken together, these data indicate that the increased freezing tolerance of M. demissus acclimated to low temperatures involves a conversion to anaerobic metabolism.
5. The increase in blood Ca2+ following low-temperature acclimation was associated with the increased freezing tolerance. Finally, Mg2+ simulated the effect of Ca2+ on freezing tolerance, but was only 20% as effective.
6. These results suggest that a Ca2+-dependent mechanism responsible for increasing the freezing tolerance of M. demissus exists, and that the increase in blood Ca2+ is due to a conversion to anaerobic metabolism.
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JOURNAL ARTICLE| 01 August 1977
Metabolic and Tissue Solute Changes Associated With Changes in the Freezing Tolerance of the Bivalve Mollusc Modiolus Demissus
DENNIS J. MURPHY
1 Department of Zoology, University of Maryland, College Park, Maryland 20742; Department of Zoology, Connecticut College, New London, Connecticut 06320
Revision Received: 27 Jul 1976
Online Issn: 1477-9145
Print Issn: 0022-0949
© 1977 by Company of Biologists
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DENNIS J. MURPHY; Metabolic and Tissue Solute Changes Associated With Changes in the Freezing Tolerance of the Bivalve Mollusc Modiolus Demissus. J Exp Biol 1 August 1977; 69 (1): 1–12. doi: https://doi.org/10.1242/jeb.69.1.1
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