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Miki Takao Chen-Goodspeed Misty Zhao Zhaoyang Lee Cheng Chi 《Journal of circadian rhythms》2013,11(1):1-2
Although out-of-lab investigation of the human circadian clock at the clock gene expression level remains difficult, a recent method using hair follicle cells might be useful. While exercise may function as an entrainment cue for circadian rhythms, it remains unclear whether exercise affects human circadian clock gene expression. Efforts to observe apparent effects of exercise on clock gene expression require that several specific conditions be met: intense exercise should be habitually performed at a relatively uncommon time of day over an extended period; and any relative phase shift thereby observed should be validated by comparison of exercise and no-exercise periods. Wake-up and meal times should be kept almost constant over the experimental period. The present study was conducted using a professional fighter who met these strict criteria as subject. Facial hair samples were collected at 4-h intervals around the clock to ascertain rhythms of clock gene expression. During a period in which nighttime training (from 20:00 to 22:00) was habitually performed, circadian clock gene expression was phase-delayed by 2 to 4 h compared with that during a no-exercise period. Maximum level and circadian amplitude of clock gene expression were not affected by the nighttime training. Our trial observations illustrate the possibility that heavy physical exercise might strongly affect the circadian phase of clock gene expression. Exercise might be therefore effective for the clinical care of circadian disorders. The results also suggest that athletes may require careful scheduling of heavy physical exercise to maintain normal circadian phase and ensure optimal athletic performance. 相似文献
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Xiaojia Wang Yueqi Wang Haoyang Xin Yanyou Liu Yuhui Wang Hang Zheng Zhou Jiang Chaomin Wan Zhengrong Wang Jian M Ding 《Journal of circadian rhythms》2006,4(1):9-9
Every physiological function in the human body exhibits some form of circadian rhythmicity. Under pathological conditions,
however, circadian rhythmicity may be dusrupted. Patients infected with HIV or addicted to drugs of abuse often suffer from
sleep disorders and altered circadian rhythms. Early studies in Drosophila suggested that drug seeking behavior might be related to the expression of certain circadian clock genes. Our previous research
showed that conditioned place preference with morphine treatment was altered in mice lacking the Period-1 (mPer1) circadian clock gene. Thus, we sought to investigate whether morphine treatment could alter the expression of mPer1, especially in brain regions outside the SCN and in peripheral tissues. Our results using Western blot analysis showed that
the mPER1 immunoreactivity exhibited a strong circadian rhythm in the brains of the control (Con), morphine-dependent (MD),
and morphine-withdrawal (MW) mice. However, the phase of the circadian rhythm of mPER1 expression in the brains of MD mice
significantly differed from that of the Con mice (p < 0.05). In contrast to mPER1 expression in the brain, the circadian rhythm
of mPER1 immunoreactivity in the kidneys was abolished after morphine administration, whereas the Con mice maintained robust
circadian rhythmicity of mPER1 in the kidney. Therefore, the effect of morphine on the circadian clock gene mPer1 may vary among different organs, resulting in desynchronization of circadian function between the SCN and peripheral organs. 相似文献
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Background
Recently, several papers have shown that a small subset of retinal ganglion cells (RGCs), which project to the suprachiasmatic nucleus (SCN) and contain a new photopigment called melanopsin, are the photoreceptors involved in light-dark entrainment in rodents. In our primate colony, we found a couple of common marmosets (Callithrix jacchus) that had developed progressive and spontaneous visual deficiency, most likely because of retinal degeneration of cones and/or rods. In this study, we evaluated the photoresponsiveness of the circadian system of these blind marmosets. 相似文献6.
Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing
system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic
nucleus (SCN) of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components
of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circadian regulation
extends beyond clock genes to involve various clock-controlled genes (CCGs) including various cell cycle genes. Aberrant expression
of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell
cycle and on the ability of cells to undergo apoptosis. This may lead to genomic instability and accelerated cellular proliferation
potentially promoting carcinogenesis. Different lines of evidence in mice and humans suggest that cancer may be a circadian-related
disorder. The genetic or functional disruption of the molecular circadian clock has been found in various cancers including
breast, ovarian, endometrial, prostate and hematological cancers. The acquisition of current data in circadian clock mechanism
may help chronotherapy, which takes into consideration the biological time to improve treatments by devising new therapeutic
approaches for treating circadian-related disorders, especially cancer. 相似文献
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Background
It is reported that the circadian rhythms of female mating activity differ among Drosophila species and are controlled by an endogenous circadian clock. Here, we found that the mating rhythm of D. ananassae differed from that of D. melanogaster. Moreover, to evaluate the effect of clock gene products on mating activities, we examined the mating activity of D. melanogaster timeless (tim 01) transgenic fly harboring heat-shock promotor driven-D. ananassae timeless (tim) gene (hs-AT tim 01). 相似文献8.
In humans, chronic ethanol consumption leads to a characteristic set of changes to the metabolism of lipids in the liver that
is referred to as an "alcoholic fatty liver (AFL)". In severe cases, these metabolic changes result in the enlargement and
fibrillization of the liver and are considered risk factors for cirrhosis and liver cancer. Clock-mutant mice have been shown to display abnormal lipid metabolism and alcohol preferences. To further understand the potential
interactions between ethanol consumption, lipid metabolism, and the circadian clock, we investigated the effect of chronic
ethanol intake on the lipid metabolism of Clock-mutant mice. We found that ethanol treatment produced a number of changes in the liver of Clock-mutant mice without impacting the wild-type controls. First, we found that 8 weeks of exposure to ethanol in the drinking
water increased the weight of the liver in Clock-mutant mice. Ethanol treatment also increased triglyceride content of liver in Clock-mutant and wild-type mice. This increase was larger in the mutant mice. Finally, ethanol treatment altered the expression
of a number of genes related to lipid metabolism in the Clock-mutant mice. Interestingly, this treatment did not impact circadian clock gene expression in the liver of either genotype.
Thus, ethanol produces a number of changes in the liver of Clock-mutant mice that are not seen in the wild-type mice. These changes are consistent with the possibility that disturbance of
circadian rhythmicity associated with the Clock mutation could be a risk factor for the development of an alcoholic fatty liver. 相似文献
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Background
All animals thus far studied sleep, but little is known about the ecological factors that generate differences in sleep characteristics across species, such as total sleep duration or division of sleep into multiple bouts across the 24-hour period (i.e., monophasic or polyphasic sleep activity). Here we address these questions using an evolutionary agent-based model. The model is spatially explicit, with food and sleep sites distributed in two clusters on the landscape. Agents acquire food and sleep energy based on an internal circadian clock coded by 24 traits (one for each hour of the day) that correspond to "genes" that evolve by means of a genetic algorithm. These traits can assume three different values that specify the agents' behavior: sleep (or search for a sleep site), eat (or search for a food site), or flexibly decide action based on relative levels of sleep energy and food energy. Individuals with higher fitness scores leave more offspring in the next generation of the simulation, and the model can therefore be used to identify evolutionarily adaptive circadian clock parameters under different ecological conditions. 相似文献10.
Jens Joschinski Katharina Beer Charlotte Helfrich-F?rster Jochen Krauss 《Journal of insect science (Online)》2016,16(1)
Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum (Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light–dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant’s rhythmicity. 相似文献
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Background
A stable and systematic daily change in light levels at dawn and dusk provides the most reliable indicator of the phase of the day. It is likely that organisms have evolved mechanisms to use these twilight transitions as the primary zeitgeber to adjust their circadian phases. In this study, we investigated under natural illumination conditions the effects of daylight exposure restricted to twilights on the timing of testicular regression and locomotor activity of the house sparrow (Passer domesticus), which possesses a strongly self-sustaining circadian system. 相似文献13.
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Background
Recent advances in sociogenomics allow for comparative analyses of molecular mechanisms regulating the development of social behavior. In eusocial insects, one key aspect of their sociality, the division of labor, has received the most attention. Age-related polyethism, a derived form of division of labor in ants and bees where colony tasks are allocated among distinct behavioral phenotypes, has traditionally been assumed to be a product of convergent evolution. Previous work has shown that the circadian clock is associated with the development of behavior and division of labor in honeybee societies. We cloned the ortholog of the clock gene, period, from a harvester ant (Pogonomyrmex occidentalis) and examined circadian rhythms and daily activity patterns in a species that represents an evolutionary origin of eusociality independent of the honeybee. 相似文献15.
Background
Many genes control circadian period in mice. Prior studies suggested a quantitative trait locus (QTL) on proximal mouse chromosome 12 for interstrain differences in circadian period. Since the B6.D2NAhr d /J strain has DBA/2 alleles for a portion of proximal chromosome 12 introgressed onto its C57BL/6J background, we hypothesized that these mice would have a shorter circadian period than C57BL/6J mice. 相似文献16.
Ani Englund Leena Kovanen Sirkku T Saarikoski Jari Haukka Antti Reunanen Arpo Aromaa Jouko Lönnqvist Timo Partonen 《Journal of circadian rhythms》2009,7(1):5-9
Background
Mammalian circadian clocks control multiple physiological events. The principal circadian clock generates seasonal variations in behavior as well. Seasonality elevates the risk for metabolic syndrome, and evidence suggests that disruption of the clockwork can lead to alterations in metabolism. Our aim was to analyze whether circadian clock polymorphisms contribute to seasonal variations in behavior and to the metabolic syndrome. 相似文献17.
Sevag A Kaladchibachi Brad Doble Norman Anthopoulos James R Woodgett Armen S Manoukian 《Journal of circadian rhythms》2007,5(1):3-12
Background
Bipolar disorder (BPD) is a widespread condition characterized by recurring states of mania and depression. Lithium, a direct inhibitor of glycogen synthase kinase 3 (GSK3) activity, and a mainstay in BPD therapeutics, has been proposed to target GSK3 as a mechanism of mood stabilization. In addition to mood imbalances, patients with BPD often suffer from circadian disturbances. GSK3, an essential kinase with widespread roles in development, cell survival, and metabolism has been demonstrated to be an essential component of the Drosophila circadian clock. We sought to investigate the role of GSK3 in the mammalian clock mechanism, as a possible mediator of lithium's therapeutic effects. 相似文献18.
Circadian clocks are believed to have evolved in parallel with the geological history of the earth, and have since been fine-tuned
under selection pressures imposed by cyclic factors in the environment. These clocks regulate a wide variety of behavioral
and metabolic processes in many life forms. They enhance the fitness of organisms by improving their ability to efficiently
anticipate periodic events in their external environments, especially periodic changes in light, temperature and humidity.
Circadian clocks provide fitness advantage even to organisms living under constant conditions, such as those prevailing in
the depth of oceans or in subterranean caves, perhaps by coordinating several metabolic processes in the internal milieu.
Although the issue of adaptive significance of circadian rhythms has always remained central to circadian biology research,
it has never been subjected to systematic and rigorous empirical validation. A few studies carried out on free-living animals
under field conditions and simulated periodic and aperiodic conditions of the laboratory suggest that circadian rhythms are
of adaptive value to their owners. However, most of these studies suffer from a number of drawbacks such as lack of population-level
replication, lack of true controls and lack of adequate control on the genetic composition of the populations, which in many
ways limits the potential insights gained from the studies. The present review is an effort to critically discuss studies
that directly or indirectly touch upon the issue of adaptive significance of circadian rhythms and highlight some shortcomings
that should be avoided while designing future experiments. 相似文献
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Background
Variation in circadian rhythms and nocturnality may, hypothetically, be related to or independent of genetic variation in photoperiodic mediation of seasonal changes in physiology and behavior. We hypothesized that strain variation in photoperiodism between photoperiodic F344 rats and nonphotoperiodic Harlan Sprague Dawley (HSD) rats might be caused by underlying variation in clock function. We predicted that HSD rats would have more activity during the day or subjective day, longer free-running rhythms, poor entrainment to short day length, and shorter duration of activity, traits that have been associated with nonphotoperiodism in other laboratory rodent species, relative to F344 rats. An alternative hypothesis, that differences are due to variation in melatonin secretion or responses to melatonin, predicts either no such differences or inconsistent combinations of differences.Methods
We tested these predictions by examining activity rhythms of young male F344 and HSD rats given access to running wheels in constant dark (DD), short day length (L8:D16; SD), and long day length (L16:D8; LD). We compared nocturnality (the proportion of activity during night or subjective night), duration of activity (alpha), activity onset and offset, phase angle of entrainment, and free running rhythms (tau) of F344 and HSD rats.Results
HSD rats had significantly greater activity during the day, were sometimes arrhythmic in DD, and had significantly longer tau than F344 rats, consistent with predictions. However, HSD rats had significantly longer alpha than F344 rats and both strains entrained to SD, inconsistent with predictions.Conclusion
The ability of HSD rats to entrain to SD, combined with longer alpha than F344 rats, suggests that the circadian system of HSD rats responds correctly to SD. These data offer best support for the alternative hypothesis, that differences in photoresponsiveness between F344 and HSD rats are caused by non-circadian differences in melatonin secretion or the response to melatonin. 相似文献20.
Jillian L Canton Mark R Smith Ho-Sun Choi Charmane I Eastman 《Journal of circadian rhythms》2009,7(1):8-7