2 edition of Circannual cycles in ground squirrels. found in the catalog.
Circannual cycles in ground squirrels.
Janet E. Joy
Written in English
|The Physical Object|
|Number of Pages||245|
Ground squirrels, show circannual cycles with periods normally less than a year when kept under laboratory conditions. The way in which environmental factors synchronize these cycles with the. from book Circadian Clocks (pp Entrainment of circannual rhythms of body mass and reproduction was monitored for 3 years in female golden-mantled ground squirrels maintained in a simulated.
To test the FDH, we determined the periods of the circannual body mass and estrous cycles of golden-mantled ground squirrels with circadian locomotor activity rhythms entrained to , , or hr days (T-cycles). Circannual period length did not differ among squirrels entrained to the different T-cycles; intergroup ranges were days. Quantitative analysis of liver metabolites in three stages of the circannual hibernation cycle in lined ground squirrels by NMR. Physiol Genomics –24, Link | ISI Google Scholar; Sommer A, Christensen E, Schwenger S, Seul R, Haas D, Olbrich H, Omran H, Sass JO. The molecular basis of aminoacylase 1 deficiency.
There was a circannual rhythm in the times of activity onset (psi o) and activity termination (psi T) and in the duration of the active phase (alpha) in female ground squirrels (Spermophilus lateralis) maintained in a light-dark (LD) photoperiod for 22 mo. Activity onset occurred h after light onset in the 4 mo before estrus, h. N. Mrosovsky, Circannual cycles in golden-mantled ground squirrels: Experiments with food deprivation and effects of temperature on periodicity, Journal of Comparative Physiology? A, /BF, , 4, (), ().
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Circannual rhythms were first described for hibernation in ground squirrels, where they persist under diverse lighting and temperature regimes.
Hibernating mammals maintain robust circannual cycles of seasonal weight gain, owing to increases in food intake, fattening and anabolism, and profound thermoregulatory by: Correspondingly then, a circannual rhythm may be defined as annual.
There are many different examples of circannual rhythms including the pupation rhythm in carpet beetles [ 1 ], the urge to migrate in birds [ 2 ], hibernation cycles in ground squirrels [ 3 ], and cycles of reproductive activity and moulting in ungulates [ 4 ].
Meal patterns in ground squirrels (Spermophilus lateralis) were recorded repeatedly over the course of endogenous circannual body weight cycles, with most data coming from the weight-gain manipulations were made, and the conditions were kept as constant as possible.
Meal patterns were related to the level of food intake at each observation by: 7. Golden-mantled ground squirrels (Spermophilus lateralis) sustained complete ablation of the suprachiasmatic nuclei (SCN) while being maintained under constant conditions of photoperiod, temperature and food SCN ablation, most squirrels observed for up to 3 years postsurgically underwent normal circannual cycles in body by: The existence of a circannual clock was first inferred from laboratory studies in which the annual cycle of body mass change persisted in golden-mantled ground squirrels under constant photoperiod and temperature (reviewed in Ref.).
In these squirrels, body mass typically fluctuates between – g during each cycle of the CAR that has a Cited by: Mrosovsky, N. The amplitude and period of circannual cycles of body weight in golden-mantled ground squirrels with medial hypothalamic lesions.
Brain Research, 99. Here we report results from an unbiased gas (GC) and liquid chromatography (LC)-mass spectroscopy (MS)-based metabolomic screen (12, 26, 38) comparing multiple individuals representing seven stages of the hibernator's circannual cycle. From a database containing 1, named compounds, were identified in ground squirrel plasma.
Sham-Pinx squirrels were lower during the first than during the second year of life (P c in each case, Fig. A similar relation has been observed in intact and gonadectomized squirrels of both sexes (9, 20). RESULTS Occurrence of circannual cycles.
All Pinx and Sham. Sika deers show circannual cycles under LD cycles ( LD, 6L:6D, 8L:8D and 21LD) which fail to induce the circadian entrainment (Helm and Lincoln, ). Similarly, spotted munia show. Strategies in Cold: Natural Torpidity and Thermogenesis is a collection of review papers presented at the Fifth International Symposium on Mammalian Hibernation, held at Jasper Park Lodge, Alberta, Canada on October Summary.
Endogenous circannual rhythms of male golden-mantled ground squirrels (Spermophilus lateralis) exposed to low ambient temperature (6 °C) at various times were compared to the rhythms of a control group kept in a warm room (21 °C) throughout.A week pulse of cold in the spring delayed the subsequent peak body weight and molt offset.
David E. Davis, Failure of temperature to entrain a circannual rhythm of mass in California ground squirrels (Spermophilus beecheyi), Journal of Interdisiplinary Cycle Research, /, 18, 1, (), (). Annual cycles of activity and inactivity that characterize most North American ground squirrels represent circannual rhythms (Davis, ; Michener, ).
Although these cycles are generated endogenously, they are also sensitive to environmental variables (e.g., snowmelt, ambient temperature) and behavioral events (e.g., emergence) whose. Quantitative analysis of liver metabolites in three stages of the circannual hibernation cycle in lined ground squirrels by NMR Natalie J.
Serkova,1 James C. Rose,2 L. Elaine Epperson,2 Hannah V. Carey,4 and Sandra L. Martin2,3 Departments of 1Anesthesiology and 2Cell and Developmental Biology and 3Program in Molecular Biology, University of Colorado School of Medicine, Aurora, Colorado.
Bilateral lesions of the PVN did not eliminate, phase-shift, or otherwise disrupt the circannual rhythms of body mass or reproduction. Absolute levels of body weight were unaffected by PVN ablation.
The PVN is not an essential component of the oscillatory system that generates circannual cycles in ground squirrels. Two complementary experiments were designed to study the effect of cold temperatures on the spring phase of the circannual cycle of golden-mantled ground squirrels (Spermophilus lateralis).
In the first experiment, a group of animals was kept in a warm room (22 °C) until the latter half of their weight-loss hibernation phase. They were then placed in a cold room (3 °C) for about 2 1/2 months. Thirteen-lined ground squirrels and other circannual hibernators undergo profound physiological changes on an annual basis, transitioning from summer homeothermy [body temperature (T(b)) approximately 37 degrees C] to winter heterothermy (T(b) cycling between 0 degrees C and 37 degrees C).
We hypoth. mogenesis. In the thirteen-lined ground squirrel, Ictidomys tridecemlineatus, elevated metabolic rate and T b (37°C) are maintained in each interbout arousal for 10–12 h before dropping again to initiate the next 2 wk bout of torpor.
Thus, the circannual hibernation rhythm can be viewed as a cycle between summer homeothermy and winter. The majority of biochemical studies begin with wild-trapped summer ground squirrels that are moved into standard laboratory housing with ad lib food and water, constant ambient temperature (T a) of ~21°C, and a light:dark cycle which in some studies approximates local ambient light cycles and in others is constant or similar.
In the fall. Female golden-mantled ground squirrels,Spermophilus lateralis, kept in a cool room ( °C), were food deprived and their hibernation thereby extended by 11 weeks on average compared to undeprived control animals in the same room.
The deprived group was then refed. Despite their prolonged hibernation, peak weights and onset of hibernation in the subsequent season were only 2–4 weeks later. The efficacy of photoperiod as a zeitgeber for entrainment of circannual body weight and estrous rhythms was tested in female golden-mantled ground squirrels maintained for 3 or more years in eithe.Complex experiments on the length of the photoperiod on woodchucks and several species of ground squirrels failed to alter the annual cycle of consumption of food.
Animals kept in constant conditions showed a cycle of about 11 months, but woodchucks sent to Australia changed their cycle in two years to match the seasons of the southern hemisphere.A circannual cycle is a biological process that occurs in living creatures over the period of approximately one year.
This cycle was first discovered by Ebo Gwinner and Canadian biologist Ted Pengelley. It is classified as an Infradian rhythm, which is biological process with a period longer than that of a circadian rhythm, less than one cycle per 28 hours.