Frogs and turtles: Different ectotherm overwintering strategies

Patterns of energy substrate utilization in overwintering painted turtles, Chrysemys picta

“…The use of carbohydrate can be seen by the decrease in total body glycogen, the decrease in the glycogen content of liver, and the large increase in total body and tissue lactate concentration. In the absence of oxygen, glycogen is hydrolyzed to provide glucose for energy production via anaerobic glycolysis with the subsequent production of lactate (Penney, 1987). The accumulation of lactate strongly suggests that hibernating turtles are exposed to prolonged periods of anoxia.…”

Patterns of energy substrate utilization in overwintering painted turtles, Chrysemys picta

“…The use of carbohydrate can be seen by the decrease in total body glycogen, the decrease in the glycogen content of liver, and the large increase in total body and tissue lactate concentration. In the absence of oxygen, glycogen is hydrolyzed to provide glucose for energy production via anaerobic glycolysis with the subsequent production of lactate (Penney, 1987). The accumulation of lactate strongly suggests that hibernating turtles are exposed to prolonged periods of anoxia.…”

Seasonality of Freeze Tolerance in a Subarctic Population of the Wood Frog,Rana sylvatica

“…Unlike the case with amphibian skeletal muscle, which can readily neutralize lactic acid, cardiac tissue is highly susceptible to damage from lactate accumulation [51], and this may have contributed to the reduced freeze tolerance in spring frogs. On the other hand, metabolic acidosis is partly countered by buffering from bicarbonate and calcium carbonate [52], and the seasonally high levels of bicarbonate in the plasma of some winter frogs (e.g., [53]) may help limit such damage. Furthermore, winter frogs also benefit from high levels of urea, which apparently protect against reperfusion injury to the myocardium [44].…”

Effects of hibernation on two important contractile tissues in tibetan frogs, Nanorana parkeri: a perspective from transcriptomics and metabolomics approaches

“…Winter dormancy or hibernation is an adaptive survival strategy used by many animal species to cope with seasonal changes in climate and low availability of food, a biological cycle that many amphibian species must undergo [ 1 ]. During hibernation, the body temperature of these ectothermic amphibians falls to ambient temperature [ 2 ].…”

Patterns of energy substrate utilization in overwintering painted turtles, Chrysemys picta

“…The use of carbohydrate can be seen by the decrease in total body glycogen, the decrease in the glycogen content of liver, and the large increase in total body and tissue lactate concentration. In the absence of oxygen, glycogen is hydrolyzed to provide glucose for energy production via anaerobic glycolysis with the subsequent production of lactate (Penney, 1987). The accumulation of lactate strongly suggests that hibernating turtles are exposed to prolonged periods of anoxia.…”

Seasonality of Freeze Tolerance in a Subarctic Population of the Wood Frog,Rana sylvatica

“…Unlike the case with amphibian skeletal muscle, which can readily neutralize lactic acid, cardiac tissue is highly susceptible to damage from lactate accumulation [51], and this may have contributed to the reduced freeze tolerance in spring frogs. On the other hand, metabolic acidosis is partly countered by buffering from bicarbonate and calcium carbonate [52], and the seasonally high levels of bicarbonate in the plasma of some winter frogs (e.g., [53]) may help limit such damage. Furthermore, winter frogs also benefit from high levels of urea, which apparently protect against reperfusion injury to the myocardium [44].…”

Effects of hibernation on two important contractile tissues in tibetan frogs, Nanorana parkeri: a perspective from transcriptomics and metabolomics approaches

“…Winter dormancy or hibernation is an adaptive survival strategy used by many animal species to cope with seasonal changes in climate and low availability of food, a biological cycle that many amphibian species must undergo [ 1 ]. During hibernation, the body temperature of these ectothermic amphibians falls to ambient temperature [ 2 ].…”

Patterns of energy substrate utilization in overwintering painted turtles, Chrysemys picta

“…The use of carbohydrate can be seen by the decrease in total body glycogen, the decrease in the glycogen content of liver, and the large increase in total body and tissue lactate concentration. In the absence of oxygen, glycogen is hydrolyzed to provide glucose for energy production via anaerobic glycolysis with the subsequent production of lactate (Penney, 1987). The accumulation of lactate strongly suggests that hibernating turtles are exposed to prolonged periods of anoxia.…”

Seasonality of Freeze Tolerance in a Subarctic Population of the Wood Frog,Rana sylvatica

“…Unlike the case with amphibian skeletal muscle, which can readily neutralize lactic acid, cardiac tissue is highly susceptible to damage from lactate accumulation [51], and this may have contributed to the reduced freeze tolerance in spring frogs. On the other hand, metabolic acidosis is partly countered by buffering from bicarbonate and calcium carbonate [52], and the seasonally high levels of bicarbonate in the plasma of some winter frogs (e.g., [53]) may help limit such damage. Furthermore, winter frogs also benefit from high levels of urea, which apparently protect against reperfusion injury to the myocardium [44].…”

Effects of hibernation on two important contractile tissues in tibetan frogs, Nanorana parkeri: a perspective from transcriptomics and metabolomics approaches

“…Winter dormancy or hibernation is an adaptive survival strategy used by many animal species to cope with seasonal changes in climate and low availability of food, a biological cycle that many amphibian species must undergo [ 1 ]. During hibernation, the body temperature of these ectothermic amphibians falls to ambient temperature [ 2 ].…”