Triggering of cryoprotectant synthesis by the initiation of ice nucleation in the freeze tolerant frog,Rana sylvatica

1985 ◽  
Vol 156 (2) ◽  
pp. 191-195 ◽  
Author(s):  
Janet M. Storey ◽  
Kenneth B. Storey
1993 ◽  
Vol 71 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Jon P. Costanzo ◽  
Richard E. Lee Jr.

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.


1991 ◽  
Vol 261 (6) ◽  
pp. R1346-R1350 ◽  
Author(s):  
J. P. Costanzo ◽  
R. E. Lee

Erythrocytes from the freeze-tolerant wood frog (Rana sylvatica) were subjected to in vitro tests of freeze tolerance, cryoprotection, and osmotic fragility. The responses of cells from frogs acclimated to 4 or 15 degrees C were similar. Erythrocytes that were frozen in saline hemolyzed at -4 degrees C or lower. The addition of high concentrations (150 and 1,500 mM) of glucose or glycerol, cryoprotectants produced naturally by freeze-tolerant frogs, significantly reduced cell injury at -8 degrees C, but concentrations of 1.5 or 15 mM were ineffective. Hemolysis was reduced by 94% with 1,500 mM glycerol and by 84% with 1,500 mM glucose; thus glycerol was the more effective cryoprotectant. Mean fragility values for frog erythrocytes incubated in hypertonic and hypotonic saline were 1,938 and 49 mosM, respectively. Survival in freeze tolerance and cryoprotection experiments was comparable for erythrocytes from frogs and humans, suggesting that these cells may respond similarly to freezing-related stresses. However, the breadth of osmotic tolerance, standardized for differences in isotonicity, was greater for frog erythrocytes than for human erythrocytes. Our data suggest that erythrocytes from R. sylvatica are adequately protected by glucose under natural conditions of freezing and thawing.


2016 ◽  
Vol 186 (8) ◽  
pp. 1045-1058 ◽  
Author(s):  
M. Clara F. do Amaral ◽  
Richard E. Lee ◽  
Jon P. Costanzo

2018 ◽  
Vol 23 (6) ◽  
pp. 1205-1217 ◽  
Author(s):  
Cheng-Wei Wu ◽  
Shannon N. Tessier ◽  
Kenneth B. Storey

Cryobiology ◽  
2016 ◽  
Vol 73 (3) ◽  
pp. 437
Author(s):  
J. Mattice ◽  
M. Smolinski ◽  
K. Storey

1998 ◽  
Vol 275 (3) ◽  
pp. R713-R719 ◽  
Author(s):  
Jon P. Costanzo ◽  
John A. Mugnano ◽  
Heidi M. Wehrheim ◽  
Richard E. Lee

The wood frog ( Rana sylvatica) is a freeze-tolerant species that encounters subzero temperatures during its winter breeding season, whereas the leopard frog ( R. pipiens) is freeze intolerant and breeds in spring. Osmotic and freezing tolerances of spermatozoa from these species were inferred from spermolysis rate, integrity of the plasma membrane as judged using vital dye assay, and motility rate. Sperm of R. sylvatica became motile in hypotonic media (≤220 mosmol/kg) and tolerated in vitro exposure to osmotic concentrations spanning nearly three orders of magnitude. Relative to sperm from R. sylvatica, which were unaffected by freezing at temperatures of −4°C or greater, R. pipiens sperm were more susceptible to osmotic damage and cryoinjury. These differences likely reflect cellular adaptations to somatic freezing in R. sylvatica. Unprotected sperm from both species were extensively damaged by freezing at −8°C, but the presence of glucose, the cryoprotectant used by R. sylvatica, or the permeant glycerol markedly diminished cryoinjury. These data suggest the feasibility of developing gamete cryopreservation protocols to aid efforts in conserving amphibian populations.


Cell Cycle ◽  
2012 ◽  
Vol 11 (9) ◽  
pp. 1727-1742 ◽  
Author(s):  
Jing Zhang ◽  
Kenneth B. Storey

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