Influence of conditions of artificial hibernation on energy metabolism indices in rats

Influence of the conditions of artificial hibernation on the content of ATP, ADP, AMP, cAMF in the blood and liver of rats is studied. It is established, that the entering and stay of animals in the conditions of artificial hibernation is accompanied by a decrease of the content of ADP and P(l). The animal coming out of the condition of artificial hibernation is accompanied by an increase of the content of ATP and cAMP and achievement in twenty-four hours of the level of monitoring values.     

Lipid levels and lipid peroxidation in frog tissues during hyperthermia and hibernation

The content of cholesterol, phospholipids, free fatty acids in the blood, ketone bodies and lipid peroxidation in the liver, brain, myocardium, skeletal muscles of Rana ridibunda were studied. Changes in the lipid content in blood during artificial hypothermia differ from those during hibernation and arousal. The utilization of reserve fats during hibernation is limited, but significantly rises during arousal. The ability to spontaneous lipid peroxidation under conditions of homogenate incubation at 37 degrees C does not increase in the studied tissues during hibernation.     

Effect of artificial hibernation state on intensity of metabolic processes in rabbits

Metabolic processes were investigated in the rabbit organism when modeling a condition of hibernation. It is established that during hibernation respiratory subcompensated acidosis develops in animals; the content of lactate and glutamate rises in their blood; activity of lactate dehydrogenase, malate dehydrogenase and isocytrate dehydrogenase increases in the liver cytosol of rabbits, while activity of pyruvate carboxylase and aldehyde dehydrogenase is reduced.     

Seasonal rhythms in the functioning of the hypophyseo-thyroid system of the suslik Citellus parryi

In experiments on the Arctic ground squirrel Citellus parryi, radioimmune assay of the content of thyrotropin of the hypophysis and thyroxine and triiodothyronine of the thyroid in the peripheral blood has been made at monthly intervals from July until May. It was found that during hibernation period, thyroxine and triiodothyronine concentrations in the blood of sleeping animals are high as compared with those during pre-hibernation period in autumn and active period in May. Thyrotropin content of the blood increases from October to May, being the lowest however during the season of the deepest hibernation from December to February. It is suggested that activation of the hypophysial--thyroid system after resting period in summer and autumn begins in October. During deep sleeping, it is depressed, being recovered in March. High levels of the thyroid hormones during hibernation period may be explained by metabolic strategy of the organism in hibernating animals which is directed to optimization of energy supply of hibernation.     

Functional analysis for gut microbes of the brown tree frog (Polypedates megacephalus) in artificial hibernation

Background

Annual hibernation is an adaptation that helps many animals conserve energy during food shortage in winter. This natural cycle is also accompanied by a remodeling of the intestinal immune system, which is an aspect of host biology that is both influenced by, and can itself influence, the microbiota. In amphibians, the bacteria in the intestinal tract show a drop in bacterial counts. The proportion of pathogenic bacteria is greater in hibernating frogs than that found in nonhibernating frogs. This suggests that some intestinal gut microbes in amphibians can be maintained and may contribute to the functions in this closed ecosystem during hibernation. However, these results were derived from culture-based approaches that only covered a small portion of bacteria in the intestinal tract.

Methods

In this study, we use a more comprehensive analysis, including bacterial appearance and functional prediction, to reveal the global changes in gut microbiota during artificial hibernation via high-throughput sequencing technology.

Results

Our results suggest that artificial hibernation in the brown tree frog (Polypedates megacephalus) could reduce microbial diversity, and artificially hibernating frogs tend to harbor core operational taxonomic units that are rarely distributed among nonhibernating frogs. In addition, artificial hibernation increased significantly the relative abundance of the red-leg syndrome-related pathogenic genus Citrobacter. Furthermore, functional predictions via PICRUSt and Tax4Fun suggested that artificial hibernation has effects on metabolism, disease, signal transduction, bacterial infection, and primary immunodeficiency.

Conclusions

We infer that artificial hibernation may impose potential effects on primary immunodeficiency and increase the risk of bacterial infections in the brown tree frog.

     

Properties of the enzymes of energy supply in the common frog under various physiological states. II. Changes in the heat resistance of adenosine triphosphatases and succinate dehydrogenase

The heat resistance of SDG, Na, K-ATPase and Mg-ATPase of the grass frog was determined in January, March and May, the number of animals examined being 30-40 in either experiment. It was found that the average level of the heat resistance of the enzymes studied shows significant, often differently directed changes, which depend on the physiological state of an organism. Negligible correlation between the thermal sensitivity of different enzymes of an organism during hibernation, completely disappear during the activity state.     

Glycemia and free sugar levels of the goby <Emphasis Type="Italic">Perccottus glehni</Emphasis> depending on period before the beginning and after the end of hibernation

The goby Perccottus glehni is one of the most winterhardy species of fresh-water eurythermal fish. Study of grounds of biochemical adaptation of these animals to hibernation under conditions of ice, which are currently absent, are of undoubted interest for understanding of the nature of hypometabolic states. This work deals with a study of changes in the content of glucose and other free sugars in goby blood and muscle tissue under different physiological states: active, prehibernation, and arousal after experimental cooling to negative near-zero temperature. A relatively high glycemia level with fluctuation amplitude from 9.8 ± 2.1 to 24.4 ± 2.4 mmol/ml is revealed. The minimal value of these fluctuations is recorded at the period almost coinciding with the beginning of hibernation, while the maximal value-at the period of artificial termination of the three-month hibernation in ice at ?5°C. The high blood glycemia level correlating with that in the muscle tissue might probably be due to a peculiar, probably, protector role of this sugar in adaptive mechanisms of the studied fish, not much due to winter hypothermia, but rather to winter hibernation on ice. The level of disaccharide maltose in muscle tissue that is maximal in April is predominantly in reciprocal dependence on the fructose content that is maximal in July. Dynamics of changes in the mono- and disaccharide content depending on the stage of preparation for hibernation basically coincided with the previously revealed dynamics for the fresh-water mollusc Lymnaea stagnalis, which indicates homology of mechanisms of the low-temperature adaptation for animals of different phylogenetic levels.     

Functional analysis for gut microbes of the brown tree frog (<Emphasis Type="Italic">Polypedates megacephalus</Emphasis>) in artificial hibernation

Background

Annual hibernation is an adaptation that helps many animals conserve energy during food shortage in winter. This natural cycle is also accompanied by a remodeling of the intestinal immune system, which is an aspect of host biology that is both influenced by, and can itself influence, the microbiota. In amphibians, the bacteria in the intestinal tract show a drop in bacterial counts. The proportion of pathogenic bacteria is greater in hibernating frogs than that found in nonhibernating frogs. This suggests that some intestinal gut microbes in amphibians can be maintained and may contribute to the functions in this closed ecosystem during hibernation. However, these results were derived from culture-based approaches that only covered a small portion of bacteria in the intestinal tract.

Methods

In this study, we use a more comprehensive analysis, including bacterial appearance and functional prediction, to reveal the global changes in gut microbiota during artificial hibernation via high-throughput sequencing technology.

Results

Our results suggest that artificial hibernation in the brown tree frog (Polypedates megacephalus) could reduce microbial diversity, and artificially hibernating frogs tend to harbor core operational taxonomic units that are rarely distributed among nonhibernating frogs. In addition, artificial hibernation increased significantly the relative abundance of the red-leg syndrome-related pathogenic genus Citrobacter. Furthermore, functional predictions via PICRUSt and Tax4Fun suggested that artificial hibernation has effects on metabolism, disease, signal transduction, bacterial infection, and primary immunodeficiency.

Conclusions

We infer that artificial hibernation may impose potential effects on primary immunodeficiency and increase the risk of bacterial infections in the brown tree frog.

     

An apparatus for artificial circulation in laboratory animals

An artificial circulation apparatus consisting of two membrane pneumatic adaptive diaphragmatic-type pumps and artificial film-type lungs and principle of its operation are described. The apparatus permits maintaining volume blood flow to 800 ml/min during organism resuscitation after endured clinical death including prolonged one as well.     

Lipids in mammalian hibernation and artificial hypobiosis

Membrane lipids—phospholipids, fatty acids, and cholesterol—participate in thermal adaptation of ectotherms (bacteria, amphibians, reptiles, fishes) mainly via changes in membrane viscosity caused by the degree of fatty acids unsaturation, cholesterol/phospholipids ratio, and phospholipid composition. Studies of thermal adaptation of endotherms (mammals and birds) revealed the regulatory role of lipids in hibernation. Cholesterol and fatty acids participate in regulation of the parameters of torpor, gene expression, and activity of enzymes of lipid metabolism. Some changes in lipid metabolism during artificial and natural hypobiosis, namely, increased concentration of cholesterol and fatty acids in blood and decreased cholesterol concentration in neocortex, are analogous to those observed under stress conditions and coincide with mammalian nonspecific reactions to environmental agents. It is shown that the effects of artificial and natural hypobiosis on lipid composition of mammalian cell membranes are different. Changes in lipid composition cause changes in membrane morphology during mammalian hibernation. The effect of hypobiosis on lipid composition of membranes and cell organelles is specific and seems to be defined by the role of lipids in signaling systems. Comparative study of lipid metabolism in membranes and organelles during natural and artificial hypobiosis is promising for elucidation of adaptation of mammals to low ambient temperatures.     

中国林蛙越冬死亡率的调查分析

中国林蛙（Rana chensinensis）越冬是林蛙人工养殖中的重要环节.在休眠期间林蛙死亡率高达31%,且以优良种蛙较多.利用自动控温水族箱模拟林蛙越冬,揭示这个阶段林蛙的生理机制,既具有理论意义,又可指导实践,减少种蛙的死亡.     

Activity of liver and brain arginase during hypothermia

The content of urea and activity of arginase in the brain and liver have been determined in squirrels falling into hibernation and in rats with an artificial decrease of the body temperature. It is shown that the intensity of urea synthesis under hypothermia (20, 10 degrees C) in the studied organs of animals falling into hibernation remains at high level in contrast to animals without such adaptation.     

Identification of novel blood proteins specific for mammalian hibernation.

Mammalian hibernation is a unique physiological adaptation that allows the sustainment of life under extremely low body temperatures. In the chipmunk, we found four proteins related specifically to hibernation. These proteins started to diminish in concentration in the blood before and disappeared during hibernation. These proteins reappeared in the blood as hibernation ceased and remained during nonhibernation. The complete or partial amino acid sequences of the four proteins showed that three (27-, 25-, and 20-kDa) were previously unknown, whereas another (55-kDa) is highly homologous with alpha 1-antitrypsin. The three novel proteins are homologous, indicating that they are a family. In the NH2-terminal regions of these proteins, a collagen-like amino acid sequence is present, whereas in their COOH-terminal regions, two sequences, Ser-Ala-Phe-Ala-Val-Lys and Val-Trp-Leu-Glu, are conserved. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions and gel permeation chromatography under denaturating conditions revealed that the four proteins form a 140-kDa complex in the plasma fraction. The novel proteins were detected in blood of another hibernator, the ground squirrel, but not in rodent nonhibernators, namely tree squirrels and rats. The present finding is the first identification of a hibernation-specific protein. The presence of specific proteins in hibernators suggests the involvement of genetic factors in the control of hibernation. These proteins provide valuable tools for understanding molecular mechanisms of mammalian hibernation.     

Capture, care, and captive breeding of 13-lined ground squirrels, Spermophilus tridecemlineatus

Researchers use the 13-lined ground squirrel for studies of hibernation biochemistry and physiology, as well as for modeling a variety of potential biomedical applications of hibernation physiology. It is currently necessary to capture research specimens from the wild; this presents a host of unknown variables, not least of which is the stress of captivity. Moreover, many investigators are unfamiliar with the husbandry of this species. The authors describe practical methods for their capture, year-round care (including hibernation), captive mating, and rearing of the young. These practices will allow the researcher to better standardize his or her population of research animals, optimizing the use of this interesting model organism.     

Role of the antioxidant ascorbate in hibernation and warming from hibernation

Ground squirrels tolerate up to 90% reductions in cerebral blood flow during hibernation as well as rapid reperfusion upon periodic arousal from torpor without apparent neurological damage. Thus, hibernation is studied as a model of tolerance to cerebral ischemia and other types of brain injury. Metabolic suppression likely plays a primary adaptive role that allows hibernating species to tolerate dramatic fluctuations in blood flow. Several other aspects of hibernation physiology are also consistent with tolerance to ischemia and reperfusion suggesting that multiple neuroprotective adaptations may work in concert during hibernation. The purpose of the present work is to review evidence for enhanced antioxidant defense systems during hibernation, with a focus on ascorbate, and discuss potential roles of these antioxidants during hibernation. In concert with dramatic decreases in blood flow, nutrient and oxygen delivery, plasma concentrations of the antioxidant ascorbate [(Asc)p] increase 3-5-fold during hibernation. In contrast, during re-warming, [Asc]p declines at a relatively rapid rate that peaks at the time of maximal O(2) consumption. This peak in O(2) consumption also coincides with a brief rise in plasma urate concentration consistent with a surge in reactive oxygen species production. Overall, data suggest that elevated concentration of plasma ascorbate is poised for distribution to metabolically active tissues during the surge in oxidative metabolism that accompanies re-warming during hibernation. This pool of ascorbate, as well as increased expression of other antioxidant defense systems, may protect vulnerable tissues from oxidative stress during hibernation and re-warming from hibernation. Better understanding of the role of ascorbate in hibernation may guide use of ascorbate and other antioxidants in treatment of stroke, head trauma and neurodegenerative disease.     

光照黑暗循环条件下达乌尔黄鼠的冬眠模式和能量消耗

为研究冬眠季节的光照条件对贮脂类冬眠动物入眠的影响,在达乌尔黄鼠腹腔埋植体温记录元件iButton,在体重高峰后的下降阶段置于5℃和12L:12D的光照条件下,观察测定其冬眠模式和能量消耗。达乌尔黄鼠冬眠模式出现深冬眠型、少冬眠型和不冬眠型,蛰眠阵包括深冬眠阵、短冬眠阵和日眠阵。不同冬眠阵中最低体温、冬眠阵的持续时间、阵间产热的持续时间、冷却速率和复温速率差异显著;阵间产热的最高体温基本相同。平均每日能量消耗在日眠阵中最高、短冬眠阵中居中、深冬眠阵中最低。入眠时间多集中于黑暗时相,觉醒时间多集中于光照时相。本实验结果提示,在冬眠季节施加光照黑暗循环条件可减少达乌尔黄鼠冬眠的时间,升高阵间最低体温,缩短冬眠阵与阵间产热的持续时间,降低复温速率;增加冬眠期间能量消耗。入眠与觉醒受光照条件影响,具有明显的光暗节律。     

明亮熊蜂的生物学特性及其授粉应用

明亮熊蜂Bombus lucorumL.是我国重要的授粉昆虫之一,该种熊蜂在北京地区1年1代,以蜂王休眠方式越冬。越冬蜂王4月中旬出蛰,2周以后开始产卵,5月下旬第1批工蜂开始出房,7月上旬工蜂数量达到150只左右,随后蜂群中出现雄蜂和蜂王,8~9月蜂王和雄蜂交配。10月上旬,天气逐渐变冷,交配后的蜂王开始在地下休眠越冬。在人工控制条件下可以打破蜂王的休眠期、实现1年多代繁育,提供设施农业授粉应用。     

Relations Between Hibernation and Ovarian Functions in a Temperate Zone Frog,Rana temporaria

Adult female frogs were exposed to artificial hibernation in a refrigerator, at about 1–3°C, 1–2 months earlier than in nature, isolated or together with males. Ovarian functional state at the beginning of hibernation was assessed from ovarian biopsies taken in mid-September. All frogs ovulated during hibernation which was interrupted in mid-May, but in seven out of 19 frogs ovulation was incomplete. The number of non-ovulated oocytes varied from a minor fraction to about two thirds of the complement of vitellogenic oocytes, indicating that the follicle size reached at the time of induced hibernation was at the critical level for successful maturation. This critical size was about half the normal oocyte volume at the onset of natural hibernation. There was no vitellogenic growth during hibernation, which presumably constitutes the period of follicle maturation. In five of the frogs, oogenesis sensu stricto had occurred during the period of hibernation, some oogenic events being completely finished at autopsy in mid-May and others still progressing.     

Evaluation of energy metabolism and physical work capacity of divers for determining the optimal oxygen level during breathing gas mixture under pressure up to 5.1 MPa]

A complex evaluation of energy metabolism, oxygen-transport function of blood and physical work capacity of aquanauts has been performed during three imitation divings at depths of 400, 450 and 500 m in heliox as a breathing medium. These experiments have shown that optimal levels of partial oxygen pressure in artificial chamber environment are 30-33 kPa at 4.1 MPa, 32-35 kPa at 4.6 MPa and 33-34 kPa at 5.1 MPa. It is established that 24-days exposure of aquanautes to 4.6 MPa and 10-days exposure to 5.1 MPa yield no unfavourable changes of the examined organism functions. The activated lipid exchange in combination with stable carbohydrate catabolism, the elevated levels of oxygen consumption and its partial pressure in blood and transient fluctuations of erythropoiesis activity are interpreted as compensatory responses of diverse organisms under the influence of hyperbaric factors.     

人工诱导冬眠对中华蟾蜍血液和组织中宏量营养素的影响

为探寻冬眠期间两栖动物血液和组织中宏量营养素的适应性改变过程,经人工诱导冬眠,检测了中华蟾蜍(Bufo gargarizans)在冬眠第1、3、7、14、28、42、56天的体重和脏器指数,以及血液、心、肝和骨骼肌组织中宏量营养素的含量。结果显示:1)冬眠期间中华蟾蜍体重未出现显著性变化,无性别差异。雄性蟾蜍的心、肝和腓肠肌的脏器指数显著性大于雌性(P0.01),但同一性别的脏器指数在冬眠期间无显著性变化。2)血中葡萄糖浓度自冬眠第42天起显著下降(P0.01);总蛋白在冬眠后第56天显著降低(P0.05),总胆固醇变化不显著。血中宏量营养素无性别差异。3)肝糖原自冬眠第42天起显著下降(P0.01),肌糖原自冬眠第1天起显著性下降(P0.05),而骨骼肌和心肌组织蛋白含量无显著变化。组织中宏量营养素无性别差异。人工诱导冬眠条件下,中华蟾蜍血液和组织中的糖类含量先迅速下降,血液中的蛋白成分只在深眠时才显著减少,但血液和组织中的宏量营养素水平可在1个月内维持稳定,这可能是其适应冬眠的主要生理学机制之一。