Journal articles: 'Frogs – Hibernation'

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Sato, Iwao, Kiyoshi Konishi, Masataka Sunohara, and Akiko Mikami. "Enzyme activities and morphology of Japanese brown frog (Rana japonica) mitochondria in the tibialis anterior muscle during hibernation and active life." Canadian Journal of Zoology 79, no. 7 (July 1, 2001): 1316–21. http://dx.doi.org/10.1139/z01-083.

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Enzyme activities in the respiratory chain, as well as the structure and numbers of mitochondria of the tibialis anterior muscle, during hibernation were compared with those of normally active muscle in the Japanese brown frog (Rana japonica). Morphological examination using an electron microscope showed that during hibernation, mitochondria were larger and longer and had clearly distinguishable outer and inner membranes with developed cristae. A significantly greater number of glycogen granules was found in the tibialis anterior muscle of hibernating frogs. The average cross-sectional area (CSA) of muscle fiber was much smaller in the samples from hibernating frogs than those from active frogs. The numbers of mitochondria per CSA were also much higher during hibernation than during active life. Measurements of the enzyme activities of succinate dehydrogenase, NADH-ferricyanide reductase, and succinate-O2 and NADH-O2 oxidoreductases showed different profiles between hibernation and active life. That is, all four activities were significantly higher during hibernation than during active life. Taken together, the results obtained suggest that the seasonal variations in the activities of respiratory-chain systems may be related to the seasonal morphological changes in muscle mitochondria in R. japonica.

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McInerney, Emma P., Aimee J. Silla, and Phillip G. Byrne. "Carotenoid supplementation affects the post-hibernation performance of southern corroboree frogs." Behaviour 157, no. 2 (February 6, 2020): 121–42. http://dx.doi.org/10.1163/1568539x-00003584.

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Abstract Many animals hibernate to survive winter conditions, however, arousal from hibernation generates reactive oxygen species (ROS) that can cause oxidative stress. Dietary antioxidants, like carotenoids, may reduce oxidative stress during arousal from hibernation, and assist with post-hibernation recovery and performance. We tested the effect of carotenoid supplementation on exercise performance (escape-response and activity) in southern corroboree frogs (Pseudophryne corroboree) following initial arousal from hibernation (24–48 h post-arousal) and post-recovery (six weeks post-hibernation). Carotenoids did not affect performance following initial arousal. However, carotenoids improved escape-response six weeks post-hibernation, with carotenoid-supplemented frogs hopping faster and further in their first hop than unsupplemented frogs. Carotenoids also affected post-recovery activity, with carotenoid-supplemented frogs being less mobile than unsupplemented frogs. Carotenoids may affect post-hibernation performance by reducing oxidative stress or by increasing diet quality. Our study provides novel evidence for an effect of carotenoids on performance post-hibernation and highlights the importance of nutrition to hibernating organisms.

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Tong, Qing, Xiao-peng Du, Zong-fu Hu, Li-yong Cui, and Hong-bin Wang. "Modelling the growth of the brown frog (Rana dybowskii)." PeerJ 6 (May 16, 2018): e4587. http://dx.doi.org/10.7717/peerj.4587.

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Well-controlled development leads to uniform body size and a better growth rate; therefore, the ability to determine the growth rate of frogs and their period of sexual maturity is essential for producing healthy, high-quality descendant frogs. To establish a working model that can best predict the growth performance of frogs, the present study examined the growth of one-year-old and two-year-old brown frogs (Rana dybowskii) from metamorphosis to hibernation (18 weeks) and out-hibernation to hibernation (20 weeks) under the same environmental conditions. Brown frog growth was studied and mathematically modelled using various nonlinear, linear, and polynomial functions. The model input values were statistically evaluated using parameters such as the Akaike’s information criterion. The body weight/size ratio (Kwl) and Fulton’s condition factor (K) were used to compare the weight and size of groups of frogs during the growth period. The results showed that the third- and fourth-order polynomial models provided the most consistent predictions of body weight for age 1 and age 2 brown frogs, respectively. Both the Gompertz and third-order polynomial models yielded similarly adequate results for the body size of age 1 brown frogs, while the Janoschek model produced a similarly adequate result for the body size of age 2 brown frogs. The Brody and Janoschek models yielded the highest and lowest estimates of asymptotic weight, respectively, for the body weights of all frogs. TheKwlvalue of all frogs increased from 0.40 to 3.18. TheKvalue of age 1 frogs decreased from 23.81 to 9.45 in the first four weeks. TheKvalue of age 2 frogs remained close to 10. Graphically, a sigmoidal trend was observed for body weight and body size with increasing age. The results of this study will be useful not only for amphibian research but also for frog farming management strategies and decisions.

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Irwin, Jason T., Jon P. Costanzo, and Richard E. Lee, Jr. "Terrestrial hibernation in the northern cricket frog, Acris crepitans." Canadian Journal of Zoology 77, no. 8 (November 1, 1999): 1240–46. http://dx.doi.org/10.1139/z99-087.

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We used laboratory experiments and field observations to explore overwintering in the northern cricket frog, Acris crepitans, in southern Ohio and Indiana. Cricket frogs died within 24 h when submerged in simulated pond water that was anoxic or hypoxic, but lived 8-10 days when the water was oxygenated initially. Habitat selection experiments indicated that cricket frogs prefer a soil substrate to water as temperature decreases from 8 to 2°C. These data suggested that cricket frogs hibernate terrestrially. However, unlike sympatric hylids, this species does not tolerate extensive freezing: only 2 of 15 individuals survived freezing in the -0.8 to -2.6°C range (duration 24-96 h). Cricket frogs supercooled when dry (mean supercooling point -5.5°C; range from -4.3 to -6.8°C), but were easily inoculated by external ice at temperatures between -0.5 and -0.8°C. Our data suggested that cricket frogs hibernate terrestrially but are not freeze tolerant, are not fossorial, and are incapable of supercooling in the presence of external ice. Thus we hypothesized that cricket frogs must hibernate in terrestrial sites that adequately protect against freezing. Indeed, midwinter surveys revealed cricket frogs hibernating in crayfish burrows and cracks of the pond bank, where wet soils buffered against extensive freezing of the soil.

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Boutilier, Robert G., and Julie St-Pierre. "Adaptive plasticity of skeletal muscle energetics in hibernating frogs:mitochondrial proton leak during metabolic depression." Journal of Experimental Biology 205, no. 15 (August 1, 2002): 2287–96. http://dx.doi.org/10.1242/jeb.205.15.2287.

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SUMMARYThe common frog (Rana temporaria) spends the coldest months of each year overwintering in ice-covered ponds where temperatures can vary from 0.5 to 4.0°C. Over the course of a winter season, the animals enter progressively into a state of metabolic depression that relies almost exclusively on aerobic production of ATP. However, if aerobic metabolism is threatened, for example by increasingly hypoxic conditions, decreases in the animal's metabolic rate can reach upwards of 75% compared with the 50%decrease seen during normoxia. Under these conditions, the major proportion of the overall reduction in whole-animal metabolic rate can be accounted for by metabolic suppression of the skeletal muscle (which makes up approximately 40%of body mass). Little is known about the properties of mitochondria during prolonged periods of metabolic depression, so we have examined several aspects of mitochondrial metabolism in the skeletal muscle of frogs over periods of hibernation of up to 4 months. Mitochondria isolated from the skeletal muscle of frogs hibernating in hypoxic water show a considerable reorganisation of function compared with those isolated from normoxic submerged animals at the same temperature (3°C). Both the active (state 3) and resting (state 4)respiration rates of mitochondria decrease during hypoxic, but not normoxic,hibernation. In addition, the affinity of mitochondria for oxygen increases during periods of acute hypoxic stress during normoxic hibernation as well as during long-term hibernation in hypoxic water. The decrease in mitochondrial state 4 respiration rates during hypoxic hibernation evidently occurs through a reduction in electron-transport chain activity, not through a lowered proton conductance of the mitochondrial inner membrane. The reduced aerobic capacity of frog skeletal muscle during hypoxic hibernation is accompanied by lowered activities of key enzymes of mitochondrial metabolism caused by changes in the intrinsic properties of the mitochondria. In the absence of oxygen, the mitochondrial F1Fo-ATPase (the ATP synthase) begins to run backwards as it actively pumps protons from the matrix in an attempt to maintain the mitochondrial membrane potential. At this time, the ATP synthase functions as an ATPase to preserve a certain proton-motive force. Frogs limit ATP wastage during anoxia by a profound inhibition of the ATP synthase. Taken together, our studies show that protonmotive force is lowered aerobically by restricting electron supply and during anoxia by restricting mitochondrial ATPase activity.

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Donohoe, Paul H., Timothy G. West, and Robert G. Boutilier. "Respiratory, metabolic, and acid-base correlates of aerobic metabolic rate reduction in overwintering frogs." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 274, no. 3 (March 1, 1998): R704—R710. http://dx.doi.org/10.1152/ajpregu.1998.274.3.r704.

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Aerobic metabolic rates (M˙o 2) and respiratory quotients (RQ = CO2production/M˙o 2) were measured contemporaneously in hibernating frogs Rana temporaria (L.), submerged for 90 days at 3°C. After 3 mo of submergence in fully aerated water,M˙o 2levels were 61% of those seen at the same temperature before hibernation. Over the first 40 days of hibernation, RQ values (≤0.82) favored a lipid-based metabolism that progressively shifted to an exclusively carbohydrate metabolism (RQ = 1.01) by 90 days of hibernation. Liver glycogen concentrations fell by 68% during the first 8 wk of submergence, thereafter exhibiting a less rapid rate of utilization. Conversely, muscle glycogen concentrations remained stable over the first 2 mo of the experiment before falling by 33% over the course of the remaining 2 mo, indicating that the frog was recruiting muscle glycogen reserves to fuel metabolism. Submerged frogs exhibited an extracellular acidosis during the first week of submergence, but over the course of the next 15 wk “extracellular pH” values were not significantly different from the values obtained from the control air-breathing animals. The initial extracellular acidosis was not mirrored in the intracellular compartment, and the acid-base state was not significantly different from the control values for the first 8 wk. However, over the subsequent 8- to 16-wk period, the acid-base status shifted to a lower intracellular pH-[Formula: see text] concentration set point, indicative of a metabolic acidosis. Even so, there was no indication that the acidosis could be attributed to anaerobic metabolism, as both plasma and muscle lactate levels remained low and stable. Muscle adenylate energy charge and lactate-to-pyruvate and creatine-to-phosphocreatine ratios also remained unchanged throughout hibernation. The capacity for profound metabolic rate suppression together with the ability to match substrate use to shifts in aerobic metabolic demands and the ability to fix new acid-base homeostatic set points are highly adaptive, both in terms of survival and reproductive success, to an animal that is often forced to overwinter under the cover of ice.

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Dinsmore, Steve C., and David L. Swanson. "Temporal patterns of tissue glycogen, glucose, and glycogen phosphorylase activity prior to hibernation in freeze-tolerant chorus frogs, Pseudacris triseriata." Canadian Journal of Zoology 86, no. 10 (October 2008): 1095–100. http://dx.doi.org/10.1139/z08-088.

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Freezing survival may differ among winters in chorus frogs ( Pseudacris triseriata (Wied-Neuwied, 1838)), and low freezing survival is associated with low hepatic glycogen stores. The pattern of prehibernation liver glycogen accumulation in chorus frogs is unknown. Frogs might accumulate hepatic glycogen stores until a threshold level sufficient for winter survival is attained, after which frogs enter hibernation (critical threshold hypothesis). According to this model, frogs active late in the season should only be those with low hepatic glycogen stores. Alternatively, hepatic glycogen levels might continue to increase throughout the fall as long as frogs remain active (continuous increase hypothesis). We tested these hypotheses by measuring liver and leg muscle glycogen, glucose, and glycogen phosphorylase activities in chorus frogs throughout the fall prehibernation period in southeastern South Dakota. Hepatic glycogen levels were significantly related to date and increased throughout the fall period, consistent with the continuous increase hypothesis. This suggests that hepatic glycogen levels do not serve as a cue for entrance into hibernation. Liver phosphorylase activity did not vary significantly with progression of the fall season and activity was lower than in winter, suggesting that the winter increment of phosphorylase activity requires some stimulus during hibernation (e.g., low temperatures).

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St-Pierre, J., M. D. Brand, and R. G. Boutilier. "The effect of metabolic depression on proton leak rate in mitochondria from hibernating frogs." Journal of Experimental Biology 203, no. 9 (May 1, 2000): 1469–76. http://dx.doi.org/10.1242/jeb.203.9.1469.

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Futile cycling of protons across the mitochondrial inner membrane accounts for 20 % or more of the total standard metabolic rate of a rat. Approximately 15 % of this total is due to proton leakage inside the skeletal muscle alone. This study examined whether the rate of proton leak is down-regulated as a part of a coordinated response to energy conservation during metabolic depression in cold-submerged frogs. We compared the proton leak rate of skeletal muscle mitochondria isolated from frogs at different stages of hibernation (control, 1 month and 4 months of submergence in normoxia and hypoxia). The kinetics of mitochondrial proton leak rate was unaltered throughout normoxic and hypoxic submergence. The state 4 respiration rates did not differ between control animals and frogs hibernating in normoxia. In contrast, the state 4 respiration rates obtained from frogs submerged in hypoxic water for 4 months were half those of control animals. This 50 % reduction in respiration rate in hypoxic hibernation was due to a reduction in electron transport chain activity and consequent decrease in mitochondrial membrane potential. We conclude that proton leak rate is reduced during metabolic depression as a secondary result of a decrease in electron transport chain activity, but that the proton conductance is unchanged. In addition, we show that the rate of proton leakage and the activity of the electron transport chain are lower in frogs than in rats, strengthening the observation that mitochondria from ectotherms have a lower proton conductance than mitochondria from endotherms.

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Akulenko, N. M. "Pecular Features of Hematopoiesis in the Liver of Mature and Immature Green Frogs (Pelophylax Esculentus Complex)." Vestnik Zoologii 50, no. 6 (December 1, 2016): 547–52. http://dx.doi.org/10.1515/vzoo-2016-0062.

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Abstract The article describes characteristic features of the hematopoiesis in mature and immature green frogs (Pelophylax esculentus complex). Quantitative differences in liver myelograms were insignificant. However, in a sample of mature animals numerous significant correlations between the number of pigment inclusions in the liver and indicators of erythropoiesis and myelopoiesis were observed. Those correlations were absent in the immature frogs. We concluded that aft er the frogs’ breeding a lack of plastic resources, in particular, hemosiderin remains up to the hibernation.

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Berger, W. Andrew, and Leszek Berger. "Progeny of water frog populations in central Poland." Amphibia-Reptilia 13, no. 2 (1992): 135–46. http://dx.doi.org/10.1163/156853892x00328.

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AbstractThe authors discuss progenies of 18 watcr frog populations. Individuals with esculenta phenotype which arc hybridogenetic hybrids between Rana ridibunda and Rana lessonae are the most numerous frogs among the adults and progeny. Esculenta tadpoles began and finished their metamorphosis mostly as first, and in progeny with esculenta phenotype there were more females than males. In pure esculenta population most of progeny belonged to ridibunda phenotype and female sex. The froglets caught in August were larger on an average than those in October or after hibernation.

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Donohoe, P. H., T. G. West, and R. G. Boutilier. "Factors affecting membrane permeability and ionic homeostasis in the cold-submerged frog." Journal of Experimental Biology 203, no. 2 (January 15, 2000): 405–14. http://dx.doi.org/10.1242/jeb.203.2.405.

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Frogs (Rana temporaria) were submerged at 3 degrees C in either normoxic (P(O2)=155 mmHg, P(O2)=20 kPa) or hypoxic (P(O2)=60 mmHg; P(O2)=8 kPa) water for up to 16 weeks, and denied air access, to mimic the conditions of an ice-covered pond during the winter. The activity of the skeletal muscle Na(+)/K(+) pump over the first 2 months of hibernation, measured by ouabain-inhibitable (22)Na(+) efflux, was reduced by 30 % during normoxia and by up to 50 % during hypoxia. The reduction in Na(+)/K(+) pump activity was accompanied by reductions in passive (22)Na(+) influx and (86)Rb(+) efflux (effectively K(+) efflux) across the sarcolemma. This may be due to a decreased Na(+) permeability of the sarcolemma and a 75 % reduction in K(+) leak mediated by ATP-sensitive K(+) channels (‘K(ATP)’ channels). The lowered rates of (22)Na(+) and (86)Rb(+) flux are coincident with lowered transmembrane ion gradients for [Na(+)] and [K(+)], which may also lower Na(+)/K(+) pump activity. The dilution of extracellular [Na(+)] and intracellular [K(+)] may be partially explained by increased water retention by the whole animal, although measurements of skeletal muscle fluid compartments using (3)H-labelled inulin suggested that the reduced ion gradients represented a new steady state for skeletal muscle. Conversely, intracellular ion homeostasis within ventricular muscle was maintained at pre-submergence levels, despite a significant increase in tissue water content, with the exception of the hypoxic frogs following 4 months of submergence. Both ventricular muscles and skeletal muscles maintained resting membrane potential at pre-submergence levels throughout the entire period of hibernation. The ability of the skeletal muscle to maintain its resting membrane potential, coincident with decreased Na(+)/K(+) pump activity and lowered membrane permeability, provided evidence of functional channel arrest as an energy-sparing strategy during hibernation in the cold-submerged frog.

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Barni, Sergio, Franco Bernini, and Paola De Piceis Polver. "Ultrastructural changes of the air-blood barrier in the lung of Rana esculenta during natural hibernation." Amphibia-Reptilia 17, no. 2 (1996): 141–47. http://dx.doi.org/10.1163/156853896x00171.

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AbstractPossible changes of the air-blood barrier in naturally hibernating frogs were examined by transmission electron microscopy and measured with an eye-piece micrometer under light microscopy. During hibernation a reduction of the "alveolar" air-space and a folding of the air-blood barrier were noticed: the thickness of the latter in the deep lung septa was double that seen in the active phase, as a consequence of deeper changes of the interstitial and surface epithelial components. An increase in electron-dense multilamellar bodies inside the pneumocyte cytoplasm was also observed. These morphological characteristics are indicative of a hypofunctionality in the lung respiratory components and may be related to a decrease in oxygen consumption during this quiescent phase of the annual life cycle.

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Jackson, Donald C., and Gordon R. Ultsch. "Physiology of hibernation under the ice by turtles and frogs." Journal of Experimental Zoology Part A: Ecological Genetics and Physiology 313A, no. 6 (March 26, 2010): 311–27. http://dx.doi.org/10.1002/jez.603.

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Socha, Małgorzata, and Maria Ogielska. "Age structure, size and growth rate of water frogs from central European natural Pelophylax ridibundus-Pelophylax esculentus mixed populations estimated by skeletochronology." Amphibia-Reptilia 31, no. 2 (2010): 239–50. http://dx.doi.org/10.1163/156853810791069119.

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AbstractCentral European water frog Pelophylax esculentus (formerly known as Rana esculenta) is a natural hybrid between P. lessonae and P. ridibundus. The hybrids reproduce by hybridogenesis and usually share populations with one of the parental species. Natural ridibundus-esculentus (R-E) mixed populations are rare. The population described herein is composed of 80% P. ridibundus and 20% P. esculentus represented by both sexes. We analyzed 159 adults and 228 juveniles. Age of adults collected from breeding sites ranged from 2 to 6 years in males and from 3 to 7 years in females of both taxa. The percentage of individuals older than 5 years was low. Average age of P. ridibundus was higher than that of P. esculentus. In P. ridibundus the average age of females was higher than that of males. In P. esculentus the difference between ages of females and males was not significant. Measurements of yearly radial growth of long bones revealed that the frogs grew intensively before reaching sexual maturity (3 years for females and 2 years for males). In the group of juveniles before I hibernation, P. esculentus were significantly bigger than P. ridibundus, however, there was no difference in body size between both taxa after I hibernation i.e., before the start of a new growth season. Mean LAG-1 diameters were significantly greater in adults P. ridibundus than in juveniles after I hibernation, but not in P. esculentus.

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Santana, FE, RR Swaisgood, JM Lemm, RN Fisher, and RW Clark. "Chilled frogs are hot: hibernation and reproduction of the Endangered mountain yellow-legged frog Rana muscosa." Endangered Species Research 27, no. 1 (February 11, 2015): 43–51. http://dx.doi.org/10.3354/esr00648.

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St-Pierre, Julie, Glenn J. Tattersall, and Robert G. Boutilier. "Metabolic depression and enhanced O2 affinity of mitochondria in hypoxic hypometabolism." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 279, no. 4 (October 1, 2000): R1205—R1214. http://dx.doi.org/10.1152/ajpregu.2000.279.4.r1205.

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This study examined whether the steady-state hypometabolism seen in overwintering frogs ( Rana temporaria) is reflected at the mitochondrial level either by a reduction in their resting (state 4) and active (state 3) respiration rates and/or by increases in O2 affinity. We isolated mitochondria from the skeletal muscle of cold-submerged frogs at different stages during their hibernation in normoxic and hypoxic water. A modest metabolic depression at the whole animal level (normoxic submergence) was not associated with a reduction in mitochondrial state 4 and state 3 respiration rates. However, mitochondria isolated from frogs that were submerged for 1 mo manifested an increase in their O2 affinity compared with controls and with animals submerged for 4 mo. Hypometabolism was more pronounced at the whole animal level during hypoxic submergence and was accompanied by 1) a reduction in mitochondrial state 4 and state 3 rates and 2) an increase in the O2affinity of mitochondria. These findings demonstrate that metabolic depression can be reflected at all levels of biological organization in hypoxia-tolerant animals.

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Gao, Xu, Changnan Jin, Arley Camargo, and Yiming Li. "Allocation trade-off under climate warming in experimental amphibian populations." PeerJ 3 (October 20, 2015): e1326. http://dx.doi.org/10.7717/peerj.1326.

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Climate change could either directly or indirectly cause population declines via altered temperature, rainfall regimes, food availability or phenological responses. However few studies have focused on allocation trade-offs between growth and reproduction under marginal resources, such as food scarce that may be caused by climate warming. Such critical changes may have an unpredicted impact on amphibian life-history parameters and even population dynamics. Here, we report an allocation strategy of adult anuran individuals involving a reproductive stage under experimental warming. Using outdoor mesocosm experiments we simulated a warming scenario likely to occur at the end of this century. We examined the effects of temperature (ambient vs. pre-/post-hibernation warming) and food availability (normal vs. low) on reproduction and growth parameters of pond frogs (Pelophylax nigromaculatus). We found that temperature was the major factor influencing reproductive time of female pond frogs, which showed a significant advancing under post-hibernation warming treatment. While feeding rate was the major factor influencing reproductive status of females, clutch size, and variation of body size for females, showed significant positive correlations between feeding rate and reproductive status, clutch size, or variation of body size. Our results suggested that reproduction and body size of amphibians might be modulated by climate warming or food availability variation. We believe this study provides some new evidence on allocation strategies suggesting that amphibians could adjust their reproductive output to cope with climate warming.

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Churchill, T. A., and K. B. Storey. "Dehydration tolerance in wood frogs: a new perspective on development of amphibian freeze tolerance." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 265, no. 6 (December 1, 1993): R1324—R1332. http://dx.doi.org/10.1152/ajpregu.1993.265.6.r1324.

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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.

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Borzée, Amaël, Miyeon Kim, Jun Young Kim, Taeho Kim, and Yikweon Jang. "Microhabitat use during brumation in the Japanese treefrog, Dryophytes japonicus." Amphibia-Reptilia 39, no. 2 (2018): 163–75. http://dx.doi.org/10.1163/15685381-17000036.

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Abstract Although amphibians undergo drastic changes in physiology and behaviour before hibernation, this phase of their life cycle (i.e., brumation) is the least understood. We investigated the patterns of microhabitat use by Dryophytes japonicus during brumation using a Harmonic Direction Finder to track 27 adults in October 2013. Most frogs used chestnut trees throughout their diel cycle. The species was most active within the “leafy vegetation” microhabitat, moving about 2 m within 72 h on average, and mostly circa 10 AM. Frogs moved less in the four other microhabitats, with individuals moving between 1 m and 50 cm, typically during the early afternoon. Around 3 pm, the microhabitat mostly used was “on bark”, with displacements almost totally halted. The use of microhabitats and shelters, as well as movements in relation to time of day, suggests that D. japonicus displays behavioural thermoregulation during brumation. This research is the first providing insights in the brumation ecology of a non-freeze-resistant Palearctic anuran.

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Loyau, Adeline, Jérémie H. Cornuau, Frances C. Clare, and Dirk S. Schmeller. "Side effects of itraconazole on post-metamorphic Alytes obstetricans after a cold stress." Amphibia-Reptilia 37, no. 4 (2016): 345–57. http://dx.doi.org/10.1163/15685381-00003064.

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Itraconazole is the most widely used treatment against Batrachochytrium dendrobatidis (Bd), the fungal pathogen causing chytridiomycosis, a proximate cause of amphibian declines. Several side effects of itraconazole treatment, ranging in severity from depigmentation to death have been reported in different amphibian species and life stages, and these side effects were observed at commonly used dosages of itraconazole. However, no studies have investigated side-effects of itraconazole in conjunction with environmental stress. Post-metamorphic midwife toads (Alytes obstetricans) that were treated with itraconazole and subsequently exposed to a cold stress (exposure to 4°C cold water) had higher mortality rates compared to untreated individuals. Moreover, adults of booroolong frogs (Litoria booroolongensis) treated with itraconazole had a higher probability to become infected when subsequently exposed to Bd. Our results suggest that a post-metamorphosis itraconazole treatment of infected midwife toads combined with a subsequent release into the wild may be an ineffective disease mitigation strategy, as the cold stress during hibernation and/or exposure to Bd in the wild may reduce the hibernation emergence rate of treated individuals in this species.

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Stewart, E. Ray, Scott A. Reese, and Gordon R. Ultsch. "The Physiology of Hibernation in Canadian Leopard Frogs (Rana pipiens) and Bullfrogs (Rana catesbeiana)." Physiological and Biochemical Zoology 77, no. 1 (January 2004): 65–73. http://dx.doi.org/10.1086/378921.

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Hudson, Nicholas J., and Craig E. Franklin. "Maintaining muscle mass during extended disuse: aestivating frogs as a model species." Journal of Experimental Biology 205, no. 15 (August 1, 2002): 2297–303. http://dx.doi.org/10.1242/jeb.205.15.2297.

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SUMMARYProlonged muscle disuse in vertebrates can lead to a pathological change resulting in muscle wasting and a loss of muscle strength. In this paper, we review muscle disuse atrophy in the vertebrates and examine the factors that influence the magnitude of the atrophic response during extended periods of inactivity, both artificially imposed (e.g. limb immobilisation) and naturally occurring, such as the quiescence associated with dormancy (e.g. hibernation and aestivation). The severity of muscle atrophy is positively correlated with mass-specific metabolic rate, and the metabolic depression that occurs during dormancy would appear to have a protective role, reducing or preventing muscle atrophy despite periods of inactivity lasting 6-9 months. In the light of these findings, the role of reactive oxygen species and antioxidants during muscle disuse is emphasised.

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Conlon, JM, K. Yano, N. Chartrel, H. Vaudry, and KB Storey. "Freeze tolerance in the wood frog Rana sylvatica is associated with unusual structural features in insulin but not in glucagon." Journal of Molecular Endocrinology 21, no. 2 (October 1, 1998): 153–59. http://dx.doi.org/10.1677/jme.0.0210153.

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The wood frog Rana sylvatica utilises glucose, derived from hepatic glycogen, as a cryoprotectant in order to survive freezing during winter hibernation, and glycogenolysis is initiated by hormonal and/or neural stimuli. The primary structure of insulin was determined from R. sylvatica and from two species of freeze-intolerant Ranid frogs R. catesbeiana (American bullfrog) and R. ridibunda (European green frog). All three insulins contain a dipeptide (Lys-Pro) extension to the N-terminus of the A-chain. The amino acid sequences of insulins from R. catesbeiana and R. ridibunda differ by only one residue (Asp for Glu at B21) but R. sylvatica insulin differs from R. catesbeiana insulin at A12 (Thr-->Met), A23 (Asn-->Ser), B5 (Tyr-->His) and B13 (Glu-->Asp). The residue at A23 (corresponding to A21 in human insulin) has been otherwise fully conserved during evolution and the residue at B13 has been strongly conserved in tetrapods. Insulin isolated from specimens of R. sylvatica that had been frozen for 24 h and from control animals that had not been frozen had the same structure, showing that freezing did not alter the pathway of post-translational processing of proinsulin. R. sylvatica glucagon was isolated in two molecular forms. Glucagon-29 was identical to R. catesbeiana glucagon-29 and contains only one amino acid substitution (Thr-->Ser) compared with human glucagon. Glucagon-36 represents glucagon-29 extended from its C-terminus by Lys-Arg-Ser-Gly-Gly-Ile-Ser and is identical to R. catesbeiana glucagon-36. We speculate that selective changes in the structure of the insulin molecule may contribute to the anomalous regulation of glycogen phosphorylase in the wood frog.

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Prokić, Marko D., Slavica S. Borković-Mitić, Imre I. Krizmanić, Jelena J. Mutić, Jelena P. Gavrić, Svetlana G. Despotović, Branka R. Gavrilović, Tijana B. Radovanović, Slađan Z. Pavlović, and Zorica S. Saičić. "Oxidative stress parameters in two Pelophylax esculentus complex frogs during pre- and post-hibernation: Arousal vs heavy metals." Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 202 (November 2017): 19–25. http://dx.doi.org/10.1016/j.cbpc.2017.07.006.

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25

Bartmańska, Jolanta, and Maria Ogielska. "Development of testes and differentiation of germ cells in water frogs of the Rana esculenta - complex (Amphibia, Anura)." Amphibia-Reptilia 20, no. 3 (1999): 251–63. http://dx.doi.org/10.1163/156853899x00286.

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AbstractThe European water frog, Rana esculenta, is a hybrid whose genome is composed of haploid chromosome sets of its parental species R. lessonae and R. ridibunda. Prior to meiosis one of the parental sets is discarded and the other is duplicated (hybridogenesis). In the parental species sex differentiation begins at tadpole stages 28-30 (Gosner, 1960), at stages 30-36 the testes are composed of proliferating pale spermatogonia 1°. At stages 36-39 a new class of spermatogonia I° (dark) appears. Before first hibernation, seminiferous lobules are filled with cysts containing germ cells at various stages of spermatogenesis up to elongating spermatids. In R. esculenta gonad development is affected from the earliest stages: the gonads are smaller and composed of reduced number of spermatogonia I°. The phase of pale spermatogonia I° proliferation is prolonged up to the second year of life. The structure of the gonads, as well as that of germ cells themselves, are often abnormal.

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26

Elmberg, Johan. "Long-term survival, length of breeding season, and operational sex ratio in a boreal population of common frogs, Rana temporaria L." Canadian Journal of Zoology 68, no. 1 (January 1, 1990): 121–27. http://dx.doi.org/10.1139/z90-017.

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A population of individually marked adult Rana temporaria was studied during the breeding season in 1979–1988 in east-central Sweden. Annual return rate averaged 31% (range 16–51%) in males and 16% (range 5–33%) in females. Return rate was not size dependent but increased with every successful previous hibernation, indicating an increased survival rate with age. Return rate was not correlated with winter harshness. Once adult, males had on average 1.5 (maximum 6) seasons with the possibility of reproducing. Corresponding values for females were 1.4 and 4. Mean length of the breeding season was 20 (SD = 2) days. Calling generally started at water temperatures below 3 °C. The lowest spawning temperature was 1 °C. Average temperatures at spawning onset and peak spawning were 5 and 6 °C, respectively. Large males tended to arrive earlier at the pond than small males. Males arrived earlier and stayed longer than did females. The overall population sex ratio was close to unity. The operational sex ratio (OSR) varied during the breeding season, averaging 0.54 (one female to two males). No male was observed to mate more than once per season. I argue that survival selection is more important to male lifetime mating success than is competition in the breeding pond (sexual selection as affected by OSR and length of the breeding season).

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Wiebler, James M., Kevin D. Kohl, Richard E. Lee, and Jon P. Costanzo. "Urea hydrolysis by gut bacteria in a hibernating frog: evidence for urea-nitrogen recycling in Amphibia." Proceedings of the Royal Society B: Biological Sciences 285, no. 1878 (May 2, 2018): 20180241. http://dx.doi.org/10.1098/rspb.2018.0241.

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Gut bacteria that produce urease, the enzyme hydrolysing urea, contribute to nitrogen balance in diverse vertebrates, although the presence of this system of urea-nitrogen recycling in Amphibia is as yet unknown. Our studies of the wood frog ( Rana sylvatica ), a terrestrial species that accrues urea in winter, documented robust urease activity by enteric symbionts and hence potential to recoup nitrogen from the urea it produces. Ureolytic capacity in hibernating (non-feeding) frogs, whose guts hosted an approximately 33% smaller bacterial population, exceeded that of active (feeding) frogs, possibly due to an inductive effect of high urea on urease expression and/or remodelling of the microbial community. Furthermore, experimentally augmenting the host's plasma urea increased bacterial urease activity. Bacterial inventories constructed using 16S rRNA sequencing revealed that the assemblages hosted by hibernating and active frogs were equally diverse but markedly differed in community membership and structure. Hibernating frogs hosted a greater relative abundance and richer diversity of genera that possess urease-encoding genes and/or have member taxa that reportedly hydrolyse urea. Bacterial hydrolysis of host-synthesized urea probably permits conservation and repurposing of valuable nitrogen not only in hibernating R. sylvatica but, given urea's universal role in amphibian osmoregulation, also in virtually all Amphibia.

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Griffin, Christine T. "Oswaldocruzia filiformis (Nematoda: Trichostrongyloidea) in frogs (Rana temporaria) from three locations in Ireland." Journal of Helminthology 63, no. 1 (March 1989): 53–62. http://dx.doi.org/10.1017/s0022149x00008737.

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ABSTRACTA total of 444 adult frogs (Rana temporaria) were obtained from three sites in the east of Ireland. Oswaldocruzia filiformis was present at all times of the year; overall, 64% of the frogs were infected, with a mean burden of 5 worms/frog. Most of the parasites were in the first half of the small intestine. A single gross lesion associated with a high worm burden is described. Female parasites were more abundant than males. Most parasitic stages of O. filiformis overwintered in hibernating hosts. Seasonal patterns in the levels of parasitization were not discerned. The intensity of infection was significantly greater in female than male frogs at one of the sites. There was little correlation between the size of host and degree of parasitization. None of the 45 frog tadpoles examined harboured O. filiformis. Frogs became infected by August of their first year.

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Layne, Jr.,, Jack R., and Matt E. Rice. "Postfreeze locomotion performance in wood frogs (Rana sylvatica) and spring peepers (Pseudacris crucifer)." Canadian Journal of Zoology 81, no. 12 (December 1, 2003): 2061–65. http://dx.doi.org/10.1139/z03-202.

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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.

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Rubin, Bruce K., Chris I. Cheeseman, Sita Gourishankar, and Malcolm King. "Is there a seasonal variation in mucus transport and nutrient absorption in the leopard frog?" Canadian Journal of Physiology and Pharmacology 70, no. 4 (April 1, 1992): 442–46. http://dx.doi.org/10.1139/y92-056.

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We postulated that as a hibernating species, frogs might have variable demands for nutrients at different seasons of the year and that this must be reflected in seasonal variations of physiologic processes related to nutrient transport and absorption. We examined the rate of mucus transport on the ciliated palate and the movement of nutrients across the intestinal lumen of leopard frogs, Rana pipiens. Mucus transport on the frog palate was strongly influenced by season, with maximal transport occurring in late June (Julian day 178, p = 0.0001; r = 0.58). This increased transport rate was associated with a summertime increase in mucus recoil (lower tangent δ) and a decrease in mucus hydration (increase in percent solids composition). Intestinal transport of leucine, lysine, and galactose did not appear to exhibit seasonal variability. These data suggest that different mechanisms may operate in determining seasonal variability in physiologic responses.Key words: mucociliary clearance, mucus viscoelasticity, intestinal absorption, Anura, seasonal variation.

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STEINER, A. A., S. O. PETENUSCI, L. G. BRENTEGANI, and L. G. S. BRANCO. "The importance of glucose for the freezing tolerance/intolerance of the anuran amphibians Rana catesbeiana and Bufo paracnemis." Revista Brasileira de Biologia 60, no. 2 (May 2000): 321–28. http://dx.doi.org/10.1590/s0034-71082000000200017.

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Several species of terrestrially hibernating frogs, turtles and insects have developed mechanisms, such as increased plasma glucose, anti-freeze proteins and antioxidant enzymes that resist to freezing, for survival at subzero temperatures. In the present study, we assessed the importance of glucose to cryoresistance of two anuran amphibians: the frog Rana catesbeiana and the toad Bufo paracnemis. Both animals were exposed to -2ºC for measurements of plasma glucose levels, liver and muscle glycogen content, haematocrit and red blood cell volume. Frogs survived cold exposure but toads did not. Blood glucose concentration increased from 40.35 ± 7.25 to 131.87 ± 20.72 mg/dl (P < 0.01) when the frogs were transferred from 20 to -2ºC. Glucose accumulation in response to cold exposition in the frogs was accompanied by a decrease (P < 0.05) in liver glycogen content from 3.94 ± 0.42 to 1.33 ± 0.36 mg/100 mg tissue, indicating that liver carbohydrate reserves were probably the primary carbon source of glucose synthesis whereas muscle carbohydrate seems unimportant. In the toads, the cold-induced hyperglycaemia was less (P < 0.05) pronounced (from 27.25 ± 1.14 to 73.72 ± 13.50 mg/dl) and no significant change could be measured in liver or muscle glycogen. Cold exposition had no effect on the haematocrit of the frogs but significantly reduced (P < 0.01) the haematocrit of toads from 20.0 ± 2.1% to 5.8 ± 1.7% due to a decreased red blood cell volume (from 1532 ± 63 to 728 ± 87 mm³). When toads were injected with glucose, blood glucose increased to levels similar to those of frogs and haematocrit did not change, but this failed to make them cryoresistent. In conclusion, the lack of cold-induced glucose catabolism may not be the only mechanism responsible for the freeze intolerance of Bufo paracnemis, a freeze-intolerant species.

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32

Cooper, Edwin L., Richard K. Wright, Alfredo E. Klempau, and Carlos T. Smith. "Hibernation alters the frog's immune system." Cryobiology 29, no. 5 (October 1992): 616–31. http://dx.doi.org/10.1016/0011-2240(92)90066-b.

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33

Buschman, H. P., W. J. van der Laarse, G. J. Stienen, and G. Elzinga. "Variation in normalized isometric tetanic force of isolated fast-twitch muscle fibres of Rana temporaria." Journal of Experimental Biology 200, no. 3 (February 1, 1997): 523–29. http://dx.doi.org/10.1242/jeb.200.3.523.

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The origin of the threefold variation found previously in isometric force normalized to cross-sectional area of single fast-twitch tibialis anterior muscle fibres of the frog Rana temporaria was studied by using (1) a strictly defined stimulus protocol, and (2) influencing the condition of the frog using artificial hibernation. Variation in normalized force was found to be influenced by the length of the rest period between tetani. After a long rest (> 6h), tetanic force production was less than for a tetanus produced after 1 h. The length of the rest period accounted for a factor of 1.24 of the total variation in normalized force. The condition of the frog also influenced normalized force production. Little variation in normalized force was observed between different fibres from the same animal, whereas a significant difference was found between animals. After artificial hibernation, force normalized to cross-sectional area remained unchanged, but force normalized to dry mass per unit length increased; the total variation increased from a factor of 1.37 to a factor of 1.64. Force normalized to muscle protein mass per unit length, however, was not affected by artificial hibernation. We conclude that variation in normalized tetanic force can be partly reduced by standardization of the stimulation protocol and normalization to protein content per unit length.

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34

Shirakawa, T., and B. I. Hirschowitz. "Seasonal fluctuations in pepsinogen secretion from frog esophageal peptic glands." American Journal of Physiology-Gastrointestinal and Liver Physiology 250, no. 4 (April 1, 1986): G484—G488. http://dx.doi.org/10.1152/ajpgi.1986.250.4.g484.

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The seasonal activity of pepsinogen secretion in the Rana catesbeiana was studied by use of peptic gland bearing esophageal mucosa mounted in a perfused double chamber. The amount of the basal pepsinogen secretion during hibernation (winter) and breeding (spring) periods was approximately 25 and 55% of basal secretion during the active (summer) period. The circumannual variation of basal secretion was highly correlated (r = 0.88, n = 37) with the pepsinogen content of the mucosa. The fractional rate of basal secretion (approximately 2% of content per hour) remained essentially constant, and pepsinogen as a fraction of total protein remained at between 20 and 25%. The results indicate that the decrease in absolute basal secretion from frog peptic glands during winter is a consequence of decreased content and hence synthesis of protein, including pepsinogen, by the mucosa. In addition, stimulated secretory responses to both bethanechol and bombesin, as a multiple of basal rate, were reduced during both hibernation and breeding periods, whereas the response to isoproterenol was entirely abolished during the hibernation period. By contrast, the secretory response to isobutylmethylxanthine remained constant (approximately 200% of basal) through all seasons, suggesting that mechanisms responsible for enzyme translocation and secretion remained intact. Reduced basal and secretagogue-stimulated secretion during hibernation and breeding seasons is thus likely due to a combination of reduced protein synthesis and decreased number or function of agonist receptors in peptic cells of the frog.

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35

St‐Pierre, J., and R. G. Boutilier. "Aerobic Capacity of Frog Skeletal Muscle during Hibernation." Physiological and Biochemical Zoology 74, no. 3 (May 2001): 390–97. http://dx.doi.org/10.1086/320428.

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36

Boutilier, Robert G. "Mechanisms of metabolic defense against hypoxia in hibernating frogs." Respiration Physiology 128, no. 3 (November 2001): 365–77. http://dx.doi.org/10.1016/s0034-5687(01)00312-7.

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37

Stumpel, Anton H. P. "On hibernation sites in the tree frog Hyla arborea." Amphibia-Reptilia 11, no. 3 (1990): 304–6. http://dx.doi.org/10.1163/156853890x00230.

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38

Sotowska-Brochocka, Jolanta, Lidia Martyńska, and Paul Licht. "Dopaminergic Inhibition of Gonadotropic Release in Hibernating Frogs, Rana temporaria." General and Comparative Endocrinology 93, no. 2 (February 1994): 192–96. http://dx.doi.org/10.1006/gcen.1994.1022.

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39

Sharma, P. N., N. Rai, and G. P. Brennan. "Ultrastructure of the tegument of the trematode Ganeo tigrinum parasitizing the intestine of indian frogs." Journal of Helminthology 70, no. 2 (June 1996): 137–42. http://dx.doi.org/10.1017/s0022149x00015297.

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AbstractThe surface tegument of G. tigrinum generally resembles that described for other digeneans. It contains surface tubercles and is covered with a glycocalyx. In the anterior region the tegument bears spines while tubular-like canals and occasional deep invaginations are present on the anteroventral surface. Two types of secretory body are present in the tegumental syncytium and produced in separate tegumental cells. Mitochondria are present in the surface syncytium, suggesting active transport occurs across the tegument in non-hibernating frogs.

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40

Storey, Kenneth B., and Janet M. Storey. "Persistence of Freeze Tolerance in Terrestrially Hibernating Frogs after Spring Emergence." Copeia 1987, no. 3 (August 5, 1987): 720. http://dx.doi.org/10.2307/1445665.

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41

Irwin, Jason T., Jon P. Costanzo, and Richard E. Lee, Jr. "Terrestrial hibernation in the northern cricket frog, Acris crepitans." Canadian Journal of Zoology 77, no. 8 (1999): 1240–46. http://dx.doi.org/10.1139/cjz-77-8-1240.

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42

Costanzo, J. P. "Cryoprotection by urea in a terrestrially hibernating frog." Journal of Experimental Biology 208, no. 21 (November 1, 2005): 4079–89. http://dx.doi.org/10.1242/jeb.01859.

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43

Cerri, Silvia, Giovanni Bottiroli, Maria Grazia Bottone, Sergio Barni, and Graziella Bernocchi. "Cell proliferation and death in the brain of active and hibernating frogs." Journal of Anatomy 215, no. 2 (August 2009): 124–31. http://dx.doi.org/10.1111/j.1469-7580.2009.01101.x.

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44

IHARA, SADAO. "Site Selection for Hibernation by the Tree Frog, Rhacophorus schlegelii." Japanese journal of herpetology 18, no. 2 (1999): 39–44. http://dx.doi.org/10.5358/hsj1972.18.2_39.

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Sengezer-Inceli, Meliha, O. Murathanoglu, Songül Castillo, Serap Sancar-Bas, and E. Kaptan. "Distribution of prolactin receptor in frog(Rana Ridibunda)dorsal skin during hibernation." Acta Biologica Hungarica 62, no. 4 (December 2011): 349–60. http://dx.doi.org/10.1556/abiol.62.2011.4.2.

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46

Barni, Sergio, Franco Bernini, Carla Fenoglio, and Carlo Reggiani. "Adaptations of the frog myocardium to conditions of natural hibernation: Morphofunctional changes." Bollettino di zoologia 61, no. 4 (January 1, 1994): 317–24. http://dx.doi.org/10.1080/11250009409355901.

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47

Kosik-Bogacka, Danuta Izabela, and Tomasz Tyrakowski. "Effect of Hibernation on Sodium and Chloride Ion Transport in Isolated Frog Skin." Folia Biologica 55, no. 1 (January 1, 2007): 47–51. http://dx.doi.org/10.3409/173491607780006317.

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48

Banas, J. A., W. J. Loesche, and G. W. Nace. "Possible mechanisms responsible for the reduced intestinal flora in hibernating leopard frogs (Rana pipiens)." Applied and Environmental Microbiology 54, no. 9 (1988): 2311–17. http://dx.doi.org/10.1128/aem.54.9.2311-2317.1988.

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Barni, Sergio, and Graziella Bernocchi. "Internalization of erythrocytes into liver parenchymal cells in naturally hibernating frogs (Rana esculenta L.)." Journal of Experimental Zoology 258, no. 2 (May 1991): 143–50. http://dx.doi.org/10.1002/jez.1402580202.

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Layne, Jack R., Richard E. Lee, and Michele M. Cutwa. "Post-Hibernation Excretion of Glucose in Urine of the Freeze Tolerant Frog Rana sylvatica." Journal of Herpetology 30, no. 1 (March 1996): 85. http://dx.doi.org/10.2307/1564715.

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Journal articles on the topic 'Frogs – Hibernation'

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