Freeze tolerance and the underlying metabolite responses in the Xizang plateau frog, Nanorana parkeri

Survival and some physiological responses to freezing were investigated in three European water frogs ( Rana lessonae, Rana ridibunda, and their hybridogen Rana esculenta). The three species exhibited different survival times during freezing (from 10 h for R. lessonae to 20 h for R. ridibunda). The time courses of percent water frozen were similar; however, because of the huge differences in body mass among species (from 10 g for Rana lessonae to nearly 100 g for Rana ridibunda), the ice mass accumulation rate varied markedly (from 0.75 ± 0.12 to 1.43 ± 0.11 g ice/h, respectively) and was lowest in the terrestrial hibernator Rana lessonae. The hybrid Rana esculenta exhibited an intermediate response between the two parental species; furthermore, within-species correlation existed between body mass and ice mass accumulation rates, suggesting the occurrence of subpopulations in this species (0.84 ± 0.08 g ice/h for small R. esculenta and 1.78 ± 0.09 g ice/h for large ones). Biochemical analyses showed accumulation of blood glucose and lactate, liver glucose (originating from glycogen), and liver alanine in Rana lessonae and Rana esculenta but not in Rana ridibunda in response to freezing. The variation of freeze tolerance between these three closely related species could bring understanding to the physiological processes involved in the evolution of freeze tolerance in vertebrates.

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Ice recrystallization inhibition proteins (IRIPs) and freeze tolerance in the cryophilic Antarctic hair grassDeschampsia antarcticaE. Desv.

Plant Cell & Environment ◽

10.1111/j.1365-3040.2009.01925.x ◽

2009 ◽

Vol 32 (4) ◽

pp. 336-348 ◽

Cited By ~ 47

Author(s):

ULRIK P. JOHN ◽

RENATA M. POLOTNIANKA ◽

KAILAYAPILLAI A. SIVAKUMARAN ◽

ORINDA CHEW ◽

LEANNE MACKIN ◽

...

Keyword(s):

Freeze Tolerance ◽

Ice Recrystallization Inhibition ◽

Ice Recrystallization ◽

Recrystallization Inhibition

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Freeze-thaw injury in erythrocytes of the freeze-tolerant wood frog, Rana sylvatica

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1991.261.6.r1346 ◽

1991 ◽

Vol 261 (6) ◽

pp. R1346-R1350 ◽

Cited By ~ 1

Author(s):

J. P. Costanzo ◽

R. E. Lee

Keyword(s):

Cell Injury ◽

Osmotic Fragility ◽

Rana Sylvatica ◽

Freeze Tolerance ◽

Wood Frog ◽

In Vitro Tests ◽

Freezing And Thawing ◽

Freeze Tolerant ◽

High Concentrations

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.

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