| uncoupling protein mrna, mitochondrial gtp-binding, and t4 5'-deiodinase activity of brown adipose tissue in daurian ground squirrel during hibernation and arousal. | the mrna level of uncoupling protein (ucp) specific for brown adipose tissue (bat) in daurian ground squirrel, was detected by using a [32p]-labeled oligonucleotide probe. the ucp concentration in mitochondria was indirectly determined by titration with its specific ligand [h3]-labeled gtp. type ii t4 5'-deiodinase of bat was assayed concomitantly. we found two species of mrna for ucp with lengths of about 1.9 and 1.5 kb, respectively, both occurring in almost the same concentration. ucp mrna co ... | 1998 | 10400495 |
| uncoupling protein1 mrna, mitochondrial gtp-binding, and t4 5'-deiodinase of brown adipose tissue in euthermic daurian ground squirrel during cold exposure. | regulation of thermogenic activity and uncoupling protein1 (ucp1) expression in brown adipose tissue (bat) were studied in euthermic daurian ground squirrel after acute and chronic cold exposure at 4 degrees c. the ucp1 concentration was indirectly determined by titration with its specific ligand [3h]-labeled gtp, and ucp1 mrna was detected by using a [32p]-labeled antisense oligonucleotide probe. both acute and chronic cold exposure stimulated up-regulation of ucp1 mrna. although ucp1 concentra ... | 2001 | 11282325 |
| cold adaptive thermogenesis in small mammals from different geographical zones of china. | the mechanisms of thermogenesis and thermoregulation were studied in the tree shrew (tupaia belangeri) and greater vole (eothenomys miletus) of the subtropical region, and brandt's vole (microtus brandti), mongolian gerbil (meriones unguiculatus), daurian ground squirrel (spermophilus dauricus) and plateau pika (ochotona curzoniae) of the northern temperate zone. resting metabolic rate (rmr) and non-shivering thermogenesis (nst) increased significantly in t. belangeri, e. miletus, m. brandti and ... | 2001 | 11440879 |
| natural infection of the ground squirrel (spermophilus spp.) with echinococcus granulosus in china. | echinococcus granulosus is usually transmitted between canid definitive hosts and ungulate intermediate hosts. | 2009 | 19771151 |
| [advance to the research of the climate factor effect on the distribution of plague]. | plague is an anthropozoonotic disease caused by the yersinia pestis ,which developed by many factors including local climate factors. in recent years, more and more studies on the effects of climate on plague were conducted. according to the researches, climate factors (mainly the rainfall and temperature) affected the development and distribution of plague by influencing the abundance of plague host animals and fleas index. the climate also affected the epidemic dynamics and the scope of plague ... | 2016 | 27141906 |
| the trophic responses of two different rodent-vector-plague systems to climate change. | plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. here, by using surveillance data, we apply structural equatio ... | 2015 | 25540277 |
| [application of best subsets regression on the risk classification for spermophilus dauricus focus]. | to study the risk classification of animal plague in spermophilus dauricus focus, using the best subsets regression (bsr) model. | 2014 | 24739558 |
| effects of cattle grazing on small mammal communities in the hulunber meadow steppe. | small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. however, how small mammals respond to cattle grazing remains controversial. a potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensi ... | 2016 | 27635323 |
| remarkable plasticity of na+, k+-atpase, ca2+-atpase and serca contributes to muscle disuse atrophy resistance in hibernating daurian ground squirrels. | we investigated cytosolic calcium (ca2+) and sarcoplasmic reticulum ca2+ regulation in skeletal muscle fibers of hibernating daurian ground squirrels (spermophilus dauricus), non-hibernating hindlimb-unloaded (hlu) squirrels, and hlu rats to clarify the molecular mechanisms involved in preventing muscle atrophy in hibernators. the na+, k+-atpase and ca2+-atpase activities in the soleus muscle (sol) of squirrels were maintained in hibernation, decreased during interbout arousal (ib-a), and increa ... | 2017 | 28874726 |
| a dramatic blood plasticity in hibernating and 14-day hindlimb unloading daurian ground squirrels (spermophilus dauricus). | we compared the effects of hibernation inactivity and 14-day hindlimb unloading in non-hibernating period on biochemical, rheological, and hematological parameters of blood in daurian ground squirrels (spermophilus dauricus). twenty-four squirrels were randomly divided into four groups: control (con), hibernation (hib), post-hibernation (post), and 14-day hindlimb unloading (hu). the results showed that serum enzymes (l-lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransfer ... | 2017 | 28501920 |
| itraq-based proteomic analysis of myofibrillar contents and relevant synthesis and proteolytic proteins in soleus muscle of hibernating daurian ground squirrels (spermophilus dauricus). | daurian ground squirrels (spermophilus dauricus) deviate from significant increase of protein catabolism and loss of myofibrillar contents during long period of hibernation inactivity. | 2016 | 27833457 |
| proliferation and apoptosis processes in the seasonal testicular development of the wild daurian ground squirrel (citellus dauricus brandt, 1844). | the aim of the present study was to elucidate the regulatory role of cell proliferation and apoptosis in testicular development of wild daurian ground squirrels during the breeding season (april), the non-breeding season (june) and before hibernation (september). gross mass and hormonal analysis showed that the testis:body mass ratio and plasma testosterone concentration fluctuated seasonally, with a peak in april and lowest values in june. similarly, spermatogenesis was fully developed in april ... | 2017 | 27679415 |
| distribution characteristics of spermophilus dauricus in manchuria city in china in 2015 through '3s' technology. | plague is a virulent infectious disease in china. in this study, '3s' technology was used to perform spatial autocorrelation analysis and spatial interpolation analysis for spermophilus dauricus (s. dauricus, a species of ground squirrel) captured in manchuria city in 2015. the results were visually inspected. during the two-month (may to july) plague surveillance in 2015, 198 s. dauricus individuals were captured in the study area in manchuria city (48 monitoring areas) by using a day-by-day ca ... | 2016 | 27660226 |
| remarkable preservation of ca(2+) homeostasis and inhibition of apoptosis contribute to anti-muscle atrophy effect in hibernating daurian ground squirrels. | the underlying mechanisms that hibernators deviated from muscle atrophy during prolonged hibernating inactivity remain elusive. this study tested the hypothesis that the maintenance of intracellular ca(2+) homeostasis and inhibition of apoptosis would be responsible for preventing muscle atrophy in hibernating daurian ground squirrels. the results showed that intracellular ca(2+) homeostasis was maintained in soleus and extensor digitorum longus (edl) in hibernation and post-hibernation, while c ... | 2016 | 27256167 |
| leptin regulates energy intake but fails to facilitate hibernation in fattening daurian ground squirrels (spermophilus dauricus). | body fat storage before hibernation affects the timing of immergence in daurian ground squirrels (spermophilus dauricus). leptin is an adipose signal and plays vital role in energy homeostasis mainly by action in brain. to test the hypothesis that leptin plays a role in facilitating the process of hibernation, squirrels were administrated with recombinant murine leptin (1μg/day) through intracerebroventricular (icv) injection for 12 days during fattening. from day 7 to 12, animals were moved int ... | 2016 | 27033037 |
| stable atrogin-1 (fbxo32) and murf1 (trim63) gene expression is involved in the protective mechanism in soleus muscle of hibernating daurian ground squirrels (spermophilus dauricus). | understanding the mechanisms that protect against or limit muscle atrophy in hibernators during prolonged inactivity has important implications for its treatment. we examined whether external factors influence the pathways regulating protein synthesis and degradation, leading to muscle atrophy prevention in daurian ground squirrels (spermophilus dauricus). we investigated the effects of 14-day hindlimb-unloading (hu) in different seasons and two-month hibernation on the soleus (sol) muscle wet m ... | 2016 | 26740574 |
| the complete mitochondrial genome of daurian ground squirrel, spermophilus dauricus. | the mitochondrial genome sequence of daurian ground squirrel, spermophilus dauricus, is determined and described for the first time in this study. the genome was a total of 16 512 bp in length and had a base composition of a (32.08%), g (12.53%), c (24.35%), and t (31.04%), indicating that the percentage of a + t (63.12%) is higher than g + c (36.88%). similar to those reported from other animal mitochondrial genomes, it possessed a typically conserved structure, including 13 protein-coding gene ... | 2016 | 26328762 |
| the expression of leptin, hypothalamic neuropeptides and ucp1 before, during and after fattening in the daurian ground squirrel (spermophilus dauricus). | the daurian ground squirrel (spermophilus dauricus) accumulates large amounts of body fat during pre-hibernation fattening. leptin, an adipose-derived hormone, plays important roles in energy balance and thermogenesis. we predicted that body fat accumulation would lead to the elevation of leptin concentration while its effect on satiety would be suppressed in hypothalamus during fattening. in addition, the uncoupling protein 1 (ucp1) in brown adipose tissue (bat) would increase and correlated po ... | 2015 | 25711781 |
| increased na+/ca2+ exchanger activity promotes resistance to excitotoxicity in cortical neurons of the ground squirrel (a hibernator). | ground squirrel, a hibernating mammalian species, is more resistant to ischemic brain stress than rat. gaining insight into the adaptive mechanisms of ground squirrels may help us design treatment strategies to reduce brain damage in patients suffering ischemic stroke. to understand the anti-stress mechanisms in ground squirrel neurons, we studied glutamate toxicity in primary cultured neurons of the daurian ground squirrel (spermophilus dauricus). at the neuronal level, for the first time, we f ... | 2014 | 25415196 |
| changes in calpains and calpastatin in the soleus muscle of daurian ground squirrels during hibernation. | we investigated changes in muscle mass, calpains, calpastatin and z-disk ultrastructure in the soleus muscle (sol) of daurian ground squirrels (spermophilus dauricus) after hibernation or hindlimb suspension to determine possible mechanisms by which muscle atrophy is prevented in hibernators. squirrels (n=30) were divided into five groups: no hibernation group (pre, n=6); hindlimb suspension group (hls, n=6); two month hibernation group (hib, n=6); two day group after 90±12 days of hibernation ( ... | 2014 | 24937257 |
| skeletal muscle is protected from disuse in hibernating dauria ground squirrels. | the purpose of this study is to test the hypothesis that muscle fibers are protected from undue atrophy in hibernating dauria ground squirrels (spermophilus dauricus, brandt). muscle mass, fiber cross sectional area (csa, video analysis) and fiber type distribution (m-atpase staining) were determined in extensor digitorum longus (edl) muscle from non-hibernating control animals (pre-h), from animals who hibernated for one (h1) or two (h2) months, and from animals 2-4days after arousal (post-h; n ... | 2012 | 22133905 |
| cold exposure increased hypothalamic orexigenic neuropeptides but not food intake in fattening daurian ground squirrels. | energy balance and thermoregulation in many fat-storing seasonal hibernators show a circannual rhythm. to understand the physiological mechanisms of the seasonal pre-hibernation fattening related to the regulation of energy expenditure and thermogenesis, we cold-exposed fattening daurian ground squirrels (spermophilus dauricus) in late summer for 3 weeks. we predicted that cold-exposed squirrels would increase food intake rather than express torpor to accommodate both fattening and thermoregulat ... | 2020 | 32947220 |
| remarkable homeostasis of protein sialylation in skeletal muscles of hibernating daurian ground squirrels (spermophilus dauricus). | as the most common post-translational protein modification, glycosylation is intimately linked to muscle atrophy. this study aimed to investigate the performance of protein glycosylation in the soleus muscle (sol) in daurian ground squirrels (spermophilus dauricus) and to determine the potential role of protein glycosylation in the mechanism underlying disuse muscle atrophy prevention. the results showed that (1) seven glycan structures comprising sialic acid α2-3 galactose (saα2-3gal) were alte ... | 2020 | 32116753 |
| seasonal expressions of prostaglandin e synthases and receptors in the prostate of the wild ground squirrel (spermophilus dauricus). | the prostate gland is a male accessory reproductive gland, whose vitality and function are under tight regulation of different hormones. prostaglandins e2 (pge2) is one of the major products generated by the actions of cyclooxygenases (cox) and prostaglandin e synthase (ptges) on arachidonic acid, and is involved in a number of physiological and pathological processes. in this study, we investigated the seasonal immunolocalizations and expressions of cox-1, cox-2 and ptges, as well as pge2 recep ... | 2020 | 31927132 |
| priority strategy of intracellular ca2+ homeostasis in skeletal muscle fibers during the multiple stresses of hibernation. | : intracellular calcium (ca2+) homeostasis plays a vital role in the preservation of skeletal muscle. in view of the well-maintained skeletal muscle found in daurian ground squirrels (spermophilus dauricus) during hibernation, we hypothesized that hibernators possess unique strategies of intracellular ca2+ homeostasis. here, cytoplasmic, sarcoplasmic reticulum (sr), and mitochondrial ca2+ levels, as well as the potential ca2+ regulatory mechanisms, were investigated in skeletal muscle fibers of ... | 2019 | 31877883 |
| remarkable protective effects of nrf2-mediated antioxidant enzymes and tissue specificity in different skeletal muscles of daurian ground squirrels over the torpor-arousal cycle. | hibernating mammals experience conditions of extreme oxidative stress, such as fasting, muscle disuse, and repeated hypoxic ischemia-reperfusion, during the torpor-arousal cycle. despite this, they experience little oxidative injury and are thus an interesting model of anti-oxidative damage. thus, in the current study, we explored the levels and underlying mechanism of oxidative stress and antioxidant capacity in three skeletal muscles [slow-twitch soleus (sol), fast-twitch extensor digitorum lo ... | 2019 | 31824343 |
| autophagy and akt-mtor signaling display periodic oscillations during torpor-arousal cycles in oxidative skeletal muscle of daurian ground squirrels (spermophilus dauricus). | whether hibernation accelerates or suppresses autophagy is still unknown. in the current study, we examined changes in autophagy in oxidative soleus (sol) muscle in summer active (sa), pre-hibernation (pre), torpor (tor), interbout arousal (iba), and post-hibernation groups of daurian ground squirrels (spermophilus dauricus). here, the sol muscle showed no significant atrophy during hibernation in regard to muscle wet weight, fiber cross-sectional area, or murf1 protein level. autophagy-related ... | 2020 | 31729534 |
| regular alteration of protein glycosylation in skeletal muscles of hibernating daurian ground squirrels (spermophilus dauricus). | glycosylation is one of the most common post-translational protein modifications and is closely associated with muscle atrophy. this study aims to investigate the changes in glycan profiles in the fast-twitch extensor digitorum longus (edl) muscles of daurian ground squirrels (spermophilus dauricus) during hibernation as well as the correlation between protein glycosylation and muscle atrophy prevention in hibernating animals. the results showed that there was no significant change in the muscle ... | 2019 | 31454680 |
| differential activation of the calpain system involved in individualized adaptation of different fast-twitch muscles in hibernating daurian ground squirrels. | we examined the lateral gastrocnemius (lg), plantaris (pl), and extensor digitorum longus (edl) muscles to determine whether differential activation of the calpain system is related to the degree of atrophy in these fast-twitch skeletal muscles during hibernation in daurian ground squirrels (spermophilus dauricus). results from morphological indices showed various degrees of atrophy in the order lg > pl > edl. furthermore, all three muscles underwent fast-to-slow fiber-type conversion in hiberna ... | 2019 | 31219776 |
| seasonal expressions of cox-1, cox-2 and ep4 in the uteri of the wild daurian ground squirrels (spermophilus dauricus). | prostaglandins (pgs) play a pivotal role in uterine reproductive process including maternal recognition of pregnancy, cell proliferation, and myometrium contractions in mammals. in this study, we investigated the immunolocalizations and expression levels of prostaglandin e2 synthases cyclo-oxygenase (cox)-1 and cox-2, as well as one of pge2 receptor subtypes 4 (ep4) in the uteri of the wild daurian ground squirrels (spermophilus dauricus) during the breeding and non-breeding seasons. histologica ... | 2019 | 31195125 |
| novel findings on ultrastructural protection of skeletal muscle fibers during hibernation of daurian ground squirrels: mitochondria, nuclei, cytoskeleton, glycogen. | we examined ultrastructure protective phenomena and mechanisms of slow and fast muscles in hibernating daurian ground squirrels (spermophilus dauricus). some degenerative changes such as slightly decreased sarcomere length and vacuolization occurred in hibernation, but periaxonal capsular borders in intrafusal fibers remained distinct and the arrangement of extrafusal fibers and z-lines unscathed. in soleus samples, the number of glycogenosomes more than tripled during hibernation. the expressio ... | 2019 | 30633347 |
| seasonal expressions of luteinising hormone receptor, follicle-stimulating hormone receptor and prolactin receptor in the epididymis of the male wild ground squirrel (spermophilus dauricus). | luteinising hormone (lh), follicle-stimulating hormone (fsh) and prolactin (prl) are pituitary-derived hormones and mediate their functions through lh receptor (lhr), fsh receptor (fshr) and prl receptor (prlr) respectively. this study aimed to investigate the seasonal expression patterns of lhr, fshr and prlr in the epididymis of the male wild ground squirrel during the breeding and non-breeding seasons. histologically, principal cells, basal cells, cilia and mature spermatozoa were found in th ... | 2019 | 30509341 |
| controllable oxidative stress and tissue specificity in major tissues during the torpor-arousal cycle in hibernating daurian ground squirrels. | mammalian hibernators experience repeated hypoxic ischaemia and reperfusion during the torpor-arousal cycle. we investigated levels of oxidative stress, antioxidant capacity, and the underlying mechanism in heart, liver, brain and kidney tissue as well as plasma during different periods of hibernation in daurian ground squirrels (spermophilus dauricus). our data showed that the levels of hydrogen peroxide significantly increased in the heart and brain during late torpor (lt) compared with levels ... | 2018 | 30305429 |
| seasonal expression of 5α-reductases and androgen receptor in the prostate gland of the wild ground squirrel (spermophilus dauricus). | the prostate gland is a male accessory reproductive gland that requires androgenic steroids for maintaining its vitality and function. the aim of the study was to investigate the localization and expressions of the androgen receptor (ar), srd5a1 and srd5a2 in the prostate glands of wild male ground squirrels during different reproductive periods by immunohistochemistry and real-time pcr. gross mass of the prostate gland was higher in the breeding season than that of the non-breeding season. hist ... | 2018 | 30057358 |
| muscle-specific activation of calpain system in hindlimb unloading rats and hibernating daurian ground squirrels: a comparison between artificial and natural disuse. | to determine whether the regulation of calpain system is involved in non-hibernators and hibernators in disused condition, the soleus (sol) and extensor digitorum longus (edl) muscles were used for investigating the muscle mass, the ratio of muscle wet weight/body weight (mww/bw), fiber-type distribution, fiber cross-sectional area (csa), and the protein expression of murf1, calpain-1, calpain-2, calpastatin, desmin, troponin t, and troponin c in hindlimb unloading rats and hibernating daurian g ... | 2018 | 30039299 |
| relationship between environmental factors and the spatial distribution of spermophilus dauricus during 2000-2015 in china. | the spermophilus dauricus is a rodent species that feeds on the tender parts of plants and seeds. it is also a natural carrier of the hepatitis b virus and the main host of the plague bacillus yersinia pestis threatening human health and the cultivated ecosystems. based on ecological niche modeling (enm) for the maxent model and arcgis for the spatial analyst model, we quantified the potential risk zone and spatial pattern of the s. dauricus outbreak during 2000-2015. we analyze the temporal and ... | 2018 | 30019314 |
| unexpected regulation pattern of the ikkβ/nf-κb/murf1 pathway with remarkable muscle plasticity in the daurian ground squirrel (spermophilus dauricus). | as a typical hibernator, the daurian ground squirrel (spermophilus dauricus) spends considerable time in a state of reduced activity with prolonged fasting. despite this, they experience little muscle atrophy and have thus become an interesting anti-disuse muscle atrophy model. the ikkβ/nf-κb signaling pathway is significant to muscle atrophy due to the protein degradation resulting from the upregulation of the e3 ubiquitin ligase murf1. the current study showed that the ikkβ/nf-κb signaling pat ... | 2018 | 29761850 |
| seasonal expressions of androgen receptor, estrogen receptors and cytochrome p450 aromatase in the uteri of the wild daurian ground squirrels (spermophilus dauricus). | the reproductive tissues including the uterus undergo dramatic changes in seasonal breeders from the breeding to non-breeding seasons. classically, sex steroid hormones play important roles in the uterine morphology and functions. to clarify the relationship between sex steroid hormones and seasonal changes in the uterine morphology and functions, the wild daurian ground squirrels (spermophilus dauricus) were used as seasonal breeder model. and the immunolocalizations and expression levels of an ... | 2018 | 29569876 |
| proteomic analysis reveals the distinct energy and protein metabolism characteristics involved in myofiber type conversion and resistance of atrophy in the extensor digitorum longus muscle of hibernating daurian ground squirrels. | previous hibernation studies demonstrated that such a natural model of skeletal muscle disuse causes limited muscle atrophy and a significant fast-to-slow fiber type shift. however, the underlying mechanism as defined in a large-scale analysis remains unclarified. isobaric tags for relative and absolute quantification (itraq) based quantitative analysis were used to examine proteomic changes in the fast extensor digitorum longus muscles (edl) of daurian ground squirrels (spermophilus dauricus). ... | 2018 | 29482114 |
| the research on the formation mechanism of extraordinary oxidative capacity of skeletal muscle in hibernating ground squirrels (spermophilus dauricus). | previous studies indicate that hibernating animals, under conditions of torpor for long periods, show an increased oxidative muscle fibers (type i) ratio and a decreased glycolytic muscle fibers (type ii) ratio in skeletal muscle and accompanied by extraordinary oxidative ability. this observation is completely contrasted with non-hibernators, which show a shift of oxidative muscle fibers (type i) to glycolytic muscle fibers (type ii). presently, the mechanisms by which these changes occur remai ... | 2015 | 31966133 |