Freeze tolerance and the dynamics of ice formation in wood frogs (Rana sylvatica) from southern Ohio

1987 ◽  
Vol 65 (8) ◽  
pp. 2062-2065 ◽  
Author(s):  
Jack R. Layne Jr. ◽  
Richard E. Lee Jr.
Keyword(s):  
Time Course ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Ice Formation ◽  
Total Water Content ◽  
Total Water ◽  
Wood Frogs ◽  
Ice Accumulation ◽  
Seasonal Factors ◽  
Ice Content

Freeze tolerance and ice formation were examined in a population of Rana sylvatica from southern Ohio following their emergence in February. Frogs were tolerant of freezing at −2.5 °C but did not survive freezing at −5.5 °C. The level of glucose in the blood of frogs frozen for 48 h at −2.5 °C was fivefold higher than in unfrozen frogs. Both interpopulational and seasonal factors appeared to modify freeze tolerance and ice accumulation in Rana sylvatica when compared with previous studies. The directly determined time course of ice formation roughly paralleled the duration of the exotherm in this species. Ice content of frogs was determined using calorimetry and integrated to the specific heat of wet and dry masses. The equilibrium ice content represented nearly two-thirds of the total water content of these frogs. Freezing beyond this level proved lethal to frogs.

Glucose concentration regulates freeze tolerance in the wood frog Rana sylvatica

1993 ◽  
Vol 181 (1) ◽  
pp. 245-255 ◽  
Author(s):  
J. P. Costanzo ◽  
R. E. Lee ◽  
P. H. Lortz
Keyword(s):  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Conclusive Evidence ◽  
Freezing Injury ◽  
Critical Determinant ◽  
Wood Frogs ◽  
Glucose Levels ◽  
Elevated Glucose ◽  
Ice Content

In spring, the lowest temperature during freezing that can be survived by wood frogs (Rana sylvatica) from southern Ohio is approximately −3 degrees C. We investigated whether the thermal limit of freeze tolerance in these frogs is regulated by tissue levels of glucose, a putative cryoprotectant that is distributed to tissues during freezing. Frogs receiving exogenous glucose injections prior to freezing showed dose-dependent increases in glucose within the heart, liver, skeletal muscle and blood. Tissue glucose concentrations were further elevated during freezing by the production of endogenous glucose. Most glucose-loaded frogs survived freezing to −5 degrees C, whereas all control (saline-injected) frogs succumbed. Further, we investigated some mechanisms by which glucose might function as a cryoprotectant in R. sylvatica. Organ dehydration, a normal, beneficial response that reduces freezing injury to tissues, occurred independently of tissue glucose concentrations. However, elevated glucose levels reduced both body ice content and in vivo erythrocyte injury. These results not only provided conclusive evidence for glucose's cryoprotective role in R. sylvatica, but also revealed that tissue glucose level is a critical determinant of freeze tolerance capacity in this species.

Freeze tolerance and ice formation in wood frogs (Rana sylvatica)

Cryobiology ◽  
1986 ◽  
Vol 23 (6) ◽  
pp. 552 ◽  
Author(s):  
Jack R. Layne ◽  
Richard E. Lee
Keyword(s):  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Ice Formation ◽  
Wood Frogs

Dehydration tolerance in wood frogs: a new perspective on development of amphibian freeze tolerance

1993 ◽  
Vol 265 (6) ◽  
pp. R1324-R1332 ◽  
Author(s):  
T. A. Churchill ◽  
K. B. Storey
Keyword(s):  
Total Body Water ◽  
Protective Layer ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Body Water ◽  
Wood Frogs ◽  
Glucose Levels ◽  
High Concentrations ◽  
Total Body ◽  
New Perspective

Wood frogs, Rana sylvatica, tolerate the loss of 50-60% of total body water during experimental dehydration. The rate of water loss for unprotected frogs is the same whether animals are frozen (at -2 degrees C) or unfrozen (at 1 degrees C) but is greatly reduced when frogs are frozen under a protective layer of moss. Dehydrational death could occur in as little as 7-9 days for unprotected animals; this indicates the importance for winter survival of selecting well-protected and damp hibernation sites. Prior dehydration affected the cooling and freezing properties of frogs, reducing supercooling point and the amount of ice formed after 24 h at -2 degrees C and acting synergistically with freezing exposure in stimulating cryoprotectant synthesis. Analysis of the effects of controlled dehydration at 5 degrees C showed that changes in body water content alone (without freezing) stimulated liver glycogenolysis and the export of high concentrations of glucose into blood and other organs. Autumn-collected frogs dehydrated to 50% of total body water lost showed glucose levels of 165-1,409 nmol/mg protein in different organs, increases of 9- to 313-fold compared with control values and reaching final levels very similar to those induced by freezing exposure. The data support the proposal that various adaptations for natural freeze tolerance may have been derived from preexisting mechanisms for dealing with water stress in amphibians and that cell volume change may be one of the signals involved in triggering and sustaining molecular adaptations (e.g., cryoprotectant output) that support freezing survival.

scholarly journals Infiltration into a Frozen Heavy Clay Soil

1989 ◽  
Vol 20 (3) ◽  
pp. 153-166 ◽  
Author(s):  
Bo Thunholm ◽  
Lars-Christer Lundin ◽  
Sten Lindell
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Arable Land ◽  
Infiltration Rate ◽  
Total Water Content ◽  
Total Water ◽  
Infiltration Rates ◽  
Crack System ◽  
Added Water ◽  
Ice Content

The infiltration of snow melt water on arable land influences both the water storage and the nutrient budget. The infiltration rate during thawing was assumed to depend on the ice content of the soil. Field measurements of soil temperature, water content and infiltration rate were made and used to test a numerical model. Efforts were made to create different ice contents in three plots by adding different amounts of water before freezing as well as during winter. The total water content in spring was not influenced by the pre-freezing addition of water, but slightly increased by water added during the winter. The simulated total water content was constant throughout the winter. The measured infiltration rates were high, at maximum 8 mm/min, and the differences between the plots were small, although lower infiltration rates were found in plots with higher amounts of added water. Simulated infiltration rates never exceeded 0.1 mm/min. The discrepancy was probably due to water flow in the partially unfrozen crack system, which the model was not capable to simulate, and to a time lag in the simulated soil temperature during thawing. Low infiltration rates were probably caused by high ice content in the cracks, originating from the added water. It should be possible to predict the infiltration capacity during thawing using a simple model which treats the crack system, the water content before freezing, and the number and intensity of warm spells during the winter.

Postfreeze locomotion performance in wood frogs (Rana sylvatica) and spring peepers (Pseudacris crucifer)

2003 ◽  
Vol 81 (12) ◽  
pp. 2061-2065 ◽  
Author(s):  
Jack R Layne, Jr., ◽  
Matt E Rice
Keyword(s):  
Treatment Group ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Early Spring ◽  
Wood Frogs ◽  
Impaired Performance ◽  
Pseudacris Crucifer ◽  
Jump Distance ◽  
Frog Species ◽  
Recovery Dynamics

Freeze tolerance exists among a few species of terrestrially hibernating North American frogs such as the wood frog (Rana sylvatica) and the spring peeper (Pseudacris crucifer). We investigated jump distance and swimming speed of these two frog species during postfreeze recovery because impaired performance, even if reversible, could have adverse ecological consequences for these frogs. Following a nonlethal freeze at –1.5 °C, R. sylvatica returned to the prefreeze level of both modes of locomotion sooner than P. crucifer (54 h vs. 11 d or longer). Wood frogs recovered slowly following more intense freezes: a –4.0 °C treatment group failed to reach the prefreeze level after 11 d, and a –3.0 °C treatment group took 54 h to reach 50% of the prefreeze level. As a result of their diminished locomotive performance, frogs recovering from natural freezes may be temporarily less able to exploit environmental resources and less able to escape predators active in winter. Nevertheless, given the massive biochemical and physiological disturbances accompanying tissue freezing, the recovery dynamics in these frogs seem sufficiently rapid to minimize most ecological risks and to permit early spring breeding. The faster recovery of locomotion in R. sylvatica compared with P. crucifer is consistent, however, with its greater northward distribution.

Oxidative damage and antioxidants in Rana sylvatica, the freeze-tolerant wood frog

1996 ◽  
Vol 271 (3) ◽  
pp. R545-R553 ◽  
Author(s):  
D. R. Joanisse ◽  
K. B. Storey
Keyword(s):  
Antioxidant Enzymes ◽  
Oxidative Damage ◽  
Time Course ◽  
Rana Pipiens ◽  
Xylenol Orange ◽  
Ischemia Reperfusion ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Antioxidant Defenses ◽  
Freeze Tolerant

Freeze-tolerant wood frogs (Rana sylvatica) must endure prolonged ischemia on freezing. Reperfusion on thawing brings with it the potential or oxidative damage due to reactive oxygen species formation, a well-known consequence of mammalian ischemia-reperfusion. To determine whether oxidative damage occurs during thawing and how frogs deal with this, we examined oxidative damage and antioxidant and prooxidant systems in tissues of Rana sylvatica and a nonfreezing relative, Rana pipiens. Glutathione status indicated little oxidative stress in tissues during freezing or thawing; an increase of the glutathione pool in the oxidized form was observed during freezing only in Rana sylvatica kidney (by 85%) and brain (by 33%). Oxidative damage to tissue lipids, measured as the levels of thiobarbituric acid-reactive substances and/or by an Fe(III)-xylenol orange assay, did not increase above control values pver a freeze-thaw time course. Correlative data showing increased activities of some antioxidant enzymes during freezing, notably glutathione peroxidase (increasing 1.2- to 2.5-fold), as well as constitutively higher activities of antioxidant enzymes and higher levels of glutathione in the freeze-tolerant species compared with Rana pipiens, suggest that antioxidant defenses play a key role in amphibian freeze tolerance.

Cryoprotectant production capacity of the freeze-tolerant wood frog, Rana sylvatica

1993 ◽  
Vol 71 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Jon P. Costanzo ◽  
Richard E. Lee Jr.
Keyword(s):  
Production Capacity ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Liver Glycogen ◽  
Wood Frog ◽  
Freezing Injury ◽  
Wood Frogs ◽  
Cryoprotectant Synthesis ◽  
Freeze Tolerant ◽  
The Relationship

Freezing survival of the wood frog (Rana sylvatica) is enhanced by the synthesis of the cryoprotectant glucose, via liver glycogenolysis. Because the quantity of glucose mobilized during freezing bears significantly on the limit of freeze tolerance, we investigated the relationship between the quantity of liver glycogen and the capacity for cryoprotectant synthesis. We successfully augmented natural levels of liver glycogen by injecting cold-conditioned wood frogs with glucose. Groups of 8 frogs having mean liver glycogen concentrations of 554 ± 57 (SE), 940 ± 57, and 1264 ± 66 μmol/g catabolized 98.7, 83.4, and 52.8%, respectively, of their glycogen reserves during 24 h of freezing to −2.5 °C. Glucose concentrations concomitantly increased, reaching 21 ± 3, 102 ± 23, and 119 ± 14 μmol/g, respectively, in the liver, and 15 ± 3, 42 ± 5, and 61 ± 5 μmol/mL, respectively, in the blood. Because the capacity for cryoprotectant synthesis depends on the amount of liver glycogen, the greatest risk of freezing injury likely occurs during spring, when glycogen reserves are minimal. Non-glucose osmolites were important in the wood frog's cryoprotectant system, especially in frogs having low glycogen levels. Presumably the natural variation in cryoprotectant synthesis capacity among individuals and populations of R. sylvatica chiefly reflects differences in glycogen reserves; however, environmental, physiological, and genetic factors likely are also involved.

EFFECTS OF OSMOTIC GRADIENTS ACROSS THE PRIMATE PLACENTAL UPON FETAL AND PLACENTAL WATER CONTENTS

PEDIATRICS ◽  
1964 ◽  
Vol 34 (3) ◽  
pp. 407-411
Author(s):  
Paul D. Bruns ◽  
Andre E. Hellegers ◽  
A. Elmore Seeds ◽  
Richard E. Behrman ◽  
Frederick C. Battaglia
Keyword(s):  
Sodium Chloride ◽  
Amniotic Fluid ◽  
Rhesus Monkeys ◽  
Solute Concentration ◽  
Total Water Content ◽  
Total Water ◽  
Concentration Gradients ◽  
Maternal Circulation ◽  
Total Body ◽  
Water Contents

Infusions of 2.7 g/100 ml sodium chloride or 30 g/100 ml disaccharide solutions into the maternal circulation of pregnant rhesus monkeys produced a significant reduction in fetal and placental total water content. At the same time large transplacental total solute concentration gradients were produced. The injection of sucrose into the amniotic fluid of pregnant rhesus monkeys produced a reduction in fetal total body water alone. The significance of these differences is discussed.

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