Adaptations of metabolism for freeze tolerance in the gray tree frog, Hyla versicolor

1985 ◽  
Vol 63 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Janet M. Storey ◽  
Kenneth B. Storey
Keyword(s):  
Energy Charge ◽  
Freeze Tolerance ◽  
Creatine Phosphate ◽  
Hyla Versicolor ◽  
Tree Frog ◽  
Mature Adult ◽  
Cryoprotectant Synthesis ◽  
Ice Content ◽  
Total Body ◽  
Gray Tree Frog

Biochemical adaptations allowing the natural survival of extracellular freezing were examined in the gray tree frog, Hyla versicolor. Laboratory-reared immature adults froze between −1 and −1.5 °C and survived 5 days of freezing at −2 °C as well as repeated rapid bouts of freeze–thaw. Measurements of ice content showed 41.5% of total body water frozen. Glycerol accumulated as the cryoprotectant in sexually mature adult H. versicolor (423 μmol/mL in blood) while both glycerol and glucose accumulated in immature adults (16.3 ± 6.8 and 25.9 ± 11.6 μmol/mL in blood, respectively). Cryoprotectant synthesis was freezing stimulated only and did not occur over long-term cold acclimation at 0 to 1 °C. Cryoprotectant synthesis was correlated with a 203% increase in liver total phosphorylase activity and an increase in phosphorylase a content from 40 to 60%. Activities of 15 other enzymes of intermediary metabolism were determined in liver and leg muscle; activities of most enzymes increased with freezing exposure as did soluble protein content. Survival of freezing depends upon anaerobic mechanisms of energy production in tissues. Frogs frozen at −2 °C accumulated lactate in liver and muscle. Energy charge dropped in both tissues and the creatine phosphate reserves of muscle were depleted.

Natural freezing survival by painted turtles Chrysemys picta marginata and C. picta bellii

1992 ◽  
Vol 262 (3) ◽  
pp. R530-R537 ◽  
Author(s):  
T. A. Churchill ◽  
K. B. Storey
Keyword(s):  
Freeze Tolerance ◽  
Chrysemys Picta ◽  
Painted Turtle ◽  
Survival Times ◽  
Painted Turtles ◽  
Ice Content ◽  
Total Body ◽  
Natural Freezing ◽  
Free Amino Acid Pools ◽  
Continuous Freezing

Hatchlings of both the Midland (Chrysemys picta marginata) and Western (C. picta bellii) subspecies of the painted turtle tolerate the freezing of extracellular body fluids while overwintering in terrestrial nests. Fall-collected hatchlings survived 3 days of continuous freezing at -2.5 degrees C, with ice contents of 43.5 +/- 1.0% of total body water (SE; n = 24) for C. picta marginata and 46.5 +/- 0.8% (n = 32) for C. picta bellii. Survival times dropped to 4-5 h when temperature was lowered to -4 degrees C, correlated with ice contents of greater than or equal to 50%. However, C. picta marginata tested immediately after excavation from nests in the spring showed greater freeze tolerance, with survival extending to 11 days at -2.5 degrees C and a higher mean ice content of 50.2 +/- 1.2% (n = 6). Spring hatchlings also had high supercooling points, -1.07 +/- 0.13 degrees C (n = 8), that dropped within 3 days to -4.83 +/- 0.83 degrees C (n = 4), suggesting a breakdown of endogenous ice-nucleating agents when hibernation ended. A search for possible cryoprotectants showed that both subspecies accumulated glucose and lactate in liver during freezing (net increase = 3-13 mumols/g wet wt); both also maintained large free amino acid pools in organs, with taurine making up 21-47% of the total.

scholarly journals The mechanics of air breathing in gray tree frog tadpoles, Hyla versicolor (Anura: Hylidae)

2020 ◽  
Vol 223 (5) ◽  
pp. jeb219311
Author(s):  
Jackson R. Phillips ◽  
Amanda E. Hewes ◽  
Kurt Schwenk
Keyword(s):  
Hyla Versicolor ◽  
Tree Frog ◽  
Air Breathing ◽  
Frog Tadpoles ◽  
Gray Tree Frog

scholarly journals Female preference functions based on call duration in the gray tree frog (Hyla versicolor)

2000 ◽  
Vol 11 (6) ◽  
pp. 663-669 ◽  
Author(s):  
H. Carl Gerhardt ◽  
Steven D. Tanner ◽  
Candice M. Corrigan ◽  
Hilary C. Walton
Keyword(s):  
Female Preference ◽  
Hyla Versicolor ◽  
Tree Frog ◽  
Call Duration ◽  
Preference Functions ◽  
Gray Tree Frog

scholarly journals Socially mediated plasticity in call timing in the gray tree frog, Hyla versicolor

2012 ◽  
Vol 24 (2) ◽  
pp. 393-401 ◽  
Author(s):  
Michael S. Reichert ◽  
H. Carl Gerhardt
Keyword(s):  
Hyla Versicolor ◽  
Tree Frog ◽  
Call Timing ◽  
Gray Tree Frog

scholarly journals Responses to freezing exposure of hatchling turtles Trachemys scripta elegans: factors influencing the development of freeze tolerance by reptiles

1992 ◽  
Vol 167 (1) ◽  
pp. 221-233 ◽  
Author(s):  
T. A. Churchill ◽  
K. B. Storey
Keyword(s):  
Amino Acid Content ◽  
Freeze Tolerance ◽  
Cold Climate ◽  
Free Amino Acid Content ◽  
Survival Times ◽  
Painted Turtles ◽  
Factors Influencing ◽  
Oxygen Sensitive ◽  
Ice Content ◽  
Total Body

Hatchling red-eared turtles Trachemys (= Pseudemys) scripta elegans (Wied) from a Louisiana population display a significant ability to withstand the freezing of extracellular body fluids. All animals survived at least 2 h of freezing at −2.5 or −4 degrees C. At −2.5 degrees C, survival declined to 50% after 6 h of freezing and no animals recovered after 24 h or longer, when mean ice content reached 54.7 +/− 1.4% of total body water. At −4 degrees C, all turtles recovered from 4 h of freezing exposure with a mean ice content of 49.6 +/− 2.4%, but survival dropped sharply thereafter with no animals recovering after 8 h, when ice content had reached 64.5 +/− 0.7%. Survival times were substantially shorter and percentage ice values greater than comparable values for hatchling painted turtles (Chrysemys picta (Schneider)) from northern populations subjected to identical freezing exposures. The ability to synthesize cryoprotectants in response to freezing was poorly developed in T. s. elegans; maximal accumulation of glucose was only 3.2 mumol g-1 wet mass in liver. Lactate content increased two- to threefold in oxygen-sensitive organs (heart and brain) during freezing, but levels of lactate and other putative cryoprotectants were unchanged in other organs. Total free amino acid content rose significantly in liver, muscle and blood during freezing; increased taurine concentration was primarily responsible for the changes in liver and blood. The capacity for freezing survival by T. s. elegans hatchlings from southern populations would be of limited use for hibernation in a cold climate, but the metabolic responses to freezing displayed by these animals might be enhanced by northern populations to increase their freeze tolerance.

Contractile properties of muscles used in sound production and locomotion in two species of gray tree frog

1999 ◽  
Vol 202 (22) ◽  
pp. 3215-3223 ◽  
Author(s):  
R.L. Marsh
Keyword(s):  
Power Output ◽  
Sound Production ◽  
Contractile Properties ◽  
Hyla Versicolor ◽  
Tree Frog ◽  
Shortening Velocity ◽  
Call Structure ◽  
Frequency Of Use ◽  
Power Outputs ◽  
Gray Tree Frog

The sound-producing muscles of frogs and toads are interesting because they have been selected to produce high-power outputs at high frequencies. The two North American species of gray tree frog, Hyla chrysoscelis and Hyla versicolor, are a diploid-tetraploid species pair. They are morphologically identical, but differ in the structure of their advertisement calls. H. chrysoscelis produces very loud pulsed calls by contracting its calling muscles at approximately 40 Hz at 20 degrees C, whereas, H. versicolor operates the homologous muscles at approximately 20 Hz at this temperature. This study examined the matching of the intrinsic contractile properties of the calling muscles to their frequency of use. I measured the isotonic and isometric contractile properties of two calling muscles, the laryngeal dilator, which presumably has a role in modulating call structure, and the external oblique, which is one of the muscles that provides the mechanical power for calling. I also examined the properties of the sartorius as a representative locomotor muscle. The calling muscles differ greatly in twitch kinetics between the two species. The calling muscles of H. chrysoscelis reach peak tension in a twitch after approximately 15 ms, compared with 25 ms for the same muscles in H. versicolor. The muscles also differ significantly in isotonic properties in the direction predicted from their calling frequencies. However, the maximum shortening velocities of the calling muscles of H. versicolor are only slightly lower than those of the comparable muscles of H. chrysoscelis. The calling muscles have similar maximum shortening velocities to the sartorius, but have much flatter force-velocity curves, which may be an adaptation to their role in cyclical power output. I conclude that twitch properties have been modified more by selection than have intrinsic shortening velocities. This difference corresponds to the differing roles of shortening velocity and twitch kinetics in determining power output at differing frequencies.

Life in a frozen state: adaptive strategies for natural freeze tolerance in amphibians and reptiles

1990 ◽  
Vol 258 (3) ◽  
pp. R559-R568 ◽  
Author(s):  
K. B. Storey
Keyword(s):  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Painted Turtle ◽  
Nucleating Agents ◽  
Garter Snakes ◽  
Isolated Cells ◽  
Subzero Temperatures ◽  
Cryoprotectant Synthesis ◽  
Total Body

Winter survival for various species of amphibians and reptiles that hibernate on land depends on freeze tolerance, the ability to survive for long periods of time with up to 65% of total body water as extracellular ice. Freeze tolerance has been described for four species of frogs, one salamander, and hatchlings of the painted turtle. A very limited tolerance also occurs in garter snakes. Studies of freeze tolerance in vertebrates have primarily focused on the wood frog Rana sylvatica and have assessed the regulation of cryoprotectant synthesis, cryoprotectant action in freezing preservation of isolated cells and tissues, metabolism and energetics under the ischemic conditions imposed by freezing, and the role of ice-nucleating agents in blood. The adaptations that preserve life at subzero temperatures for these animals illustrate the principles of vertebrate organ cryopreservation and may have important applications in the development of technology for the freezing preservation of transplantable human organs.

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