共查询到20条相似文献,搜索用时 11 毫秒
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Matthew P. Butler Kevin W. Turner Jin Ho Park Elanor E. Schoomer Irving Zucker Michael R. Gorman 《Proceedings. Biological sciences / The Royal Society》2010,277(1695):2867-2874
The seasonal reproductive cycle of photoperiodic rodents is conceptualized as a series of discrete melatonin-dependent neuroendocrine transitions. Least understood is the springtime restoration of responsiveness to winter-like melatonin signals (breaking of refractoriness) that enables animals to once again respond appropriately to winter photoperiods the following year. This has been posited to require many weeks of long days based on studies employing static photoperiods instead of the annual pattern of continually changing photoperiods under which these mechanisms evolved. Maintaining Siberian hamsters under simulated natural photoperiods, we demonstrate that winter refractoriness is broken within six weeks after the spring equinox. We then test whether a history of natural photoperiod exposure can eliminate the requirement for long-day melatonin signalling. Hamsters pinealectomized at the spring equinox and challenged 10 weeks later with winter melatonin infusions exhibited gonadal regression, indicating that refractoriness was broken. A photostimulatory effect on body weight is first observed in the last four weeks of winter. Thus, the seasonal transition to the summer photosensitive phenotype is triggered prior to the equinox without exposure to long days and is thereafter melatonin-independent. Distinctions between photoperiodic and circannual seasonal organization erode with the incorporation in the laboratory of ecologically relevant day length conditions. 相似文献
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Control of flowering and reproduction in temperate grasses 总被引:11,自引:1,他引:10
O. M. HEIDE 《The New phytologist》1994,128(2):347-362
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Melatonin administered during the fetal stage affects circadian clock in the suprachiasmatic nucleus but not in the liver 下载免费PDF全文
Pavel Houdek Lenka Polidarová Marta Nováková Kristýna Matějů Štěpán Kubík Alena Sumová 《Developmental neurobiology》2015,75(2):131-144
The mammalian circadian system develops gradually during ontogenesis, and after birth, the system is already set to a phase of the mothers. The role of maternal melatonin in the entrainment of fetal circadian clocks has been suggested, but direct evidence is lacking. In our study, intact or pinealectomized pregnant rats were exposed to constant light (LL) throughout pregnancy to suppress the endogenous melatonin and behavioral rhythms. During the last 5 days of gestation, the rats were injected with melatonin or vehicle or were left untreated. After delivery, daily expression profiles of c‐fos and Avp in the suprachiasmatic nuclei (SCN), and Per1, Per2, Rev‐erbα, and Bmal1 in the liver were measured in 1‐day‐old pups. Due to the LL exposure, no gene expression rhythms were detected in the SCN of untreated pregnant rats or in the SCN and liver of the pups. The administration of melatonin to pregnant rats entrained the pups' gene expression profiles in the SCN, but not in the liver. Melatonin did not affect the maternal behavior during pregnancy. Vehicle injections also synchronized the gene expression in the SCN but not in the liver. Melatonin and vehicle entrained the gene expression profiles to different phases, demonstrating that the effect of melatonin was apparently not due to the treatment procedure per se. The data demonstrate that in pregnant rats with suppressed endogenous melatonin levels, pharmacological doses of melatonin affect the fetal clock in the SCN but not in the liver. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 131–144, 2015 相似文献
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The avian circadian rhythm pacemaker is composed of the retina, pineal gland and suprachiasmatic nucleus. As an intact input-pacemaker-output system, each of these structures is linked within a neuroendocrine loop to influence downstream processes and peripheral oscillations. While our previous study found that monochromatic light affected the circadian rhythms of clock genes in the chick retina, the effect of the pineal gland on the response of the retinal circadian clock under monochromatic light still remains unclear. In this study, a total of 144 chicks, including sham-operated and pinealectomized groups, were exposed to white, red, green or blue light. After 2 weeks of light illumination, the circadian expression of six core clock genes (cClock, cBmal1, cCry1, cCry2, cPer2 and cPer3), melanopsin (cOpn4-1, cOpn4-2), Arylalkylamine N-acetyltransferase (cAanat) and melatonin was examined in the retina. The cBmal1, cCry1, cPer2, cPer3, cOpn4-1, cOpn4-2 and cAanat genes as well as melatonin had circadian rhythmic expression in both the sham-operated and pinealectomized groups under different monochromatic lights, while cClock and cCry2 had arrhythmic 24 h profiles in all of the light-treated groups. After pinealectomy, the rhythmicity of the clock genes, melanopsins, cAanat and melatonin in the chick retina did not change, especially the mesors, amplitudes and phases of cBmal1, cOpn4-1, cOpn4-2, cAanat and melatonin. Compared to the white light group, however, green light increased the mRNA expression of the positive-regulating clock genes cBmal1, cAanat, cOpn4-1 and cOpn4-2 as well as the melatonin content in pinealectomized chicks, whereas red light decreased their expression. These results suggest that the chick retina is a relatively independent circadian oscillator from the pineal gland, whose circadian rhythmicity (including photoreception, molecular clock and melatonin output) is not altered after pinealectomization. Moreover, green light increases ocular cAanat expression and melatonin synthesis by accelerating the expression of melanopsin and positive-regulating clock genes cBmal1 and cClock. 相似文献
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Hofman MA 《Biological reviews of the Cambridge Philosophical Society》2004,79(1):61-77
The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal component of the mammalian biological clock, the neural timing system that generates and coordinates a broad spectrum of physiological, endocrine and behavioural circadian rhythms. The pacemaker of the SCN oscillates with a near 24 h period and is entrained to the diurnal light-dark cycle. Consistent with its role in circadian timing, investigations in rodents and non-human primates furthermore suggest that the SCN is the locus of the brain's endogenous calendar, enabling organisms to anticipate seasonal environmental changes. The present review focuses on the neuronal organization and dynamic properties of the biological clock and the means by which it is synchronized with the environmental lighting conditions. It is shown that the functional activity of the biological clock is entrained to the seasonal photic cycle and that photoperiod (day length) may act as an effective zeitgeber. Furthermore, new insights are presented, based on electrophysiological and molecular studies, that the mammalian circadian timing system consists of coupled oscillators and that the clock genes of these oscillators may also function as calendar genes. In summary, there are now strong indications that the neuronal changes and adaptations in mammals that occur in response to a seasonally changing environment are driven by an endogenous circadian clock located in the SCN, and that this neural calendar is reset by the seasonal fluctuations in photoperiod. 相似文献
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Artem Pankin Chiara Campoli Xue Dong Benjamin Kilian Rajiv Sharma Axel Himmelbach Reena Saini Seth J Davis Nils Stein Korbinian Schneeberger Maria von Korff 《Genetics》2014,198(1):383-396
Phytochromes play an important role in light signaling and photoperiodic control of flowering time in plants. Here we propose that the red/far-red light photoreceptor HvPHYTOCHROME C (HvPHYC), carrying a mutation in a conserved region of the GAF domain, is a candidate underlying the early maturity 5 locus in barley (Hordeum vulgare L.). We fine mapped the gene using a mapping-by-sequencing approach applied on the whole-exome capture data from bulked early flowering segregants derived from a backcross of the Bowman(eam5) introgression line. We demonstrate that eam5 disrupts circadian expression of clock genes. Moreover, it interacts with the major photoperiod response gene Ppd-H1 to accelerate flowering under noninductive short days. Our results suggest that HvPHYC participates in transmission of light signals to the circadian clock and thus modulates light-dependent processes such as photoperiodic regulation of flowering. 相似文献
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To improve the laboratory mass rearing and the winter greenhouse use of the multicoloured Asian lady beetle Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae), the effects of photoperiod on the development and fecundity of H. axyridis were investigated at 20°C and photoperiods ranging from 0L:24D to 24L:0D. We foun'd photoperiod to significantly affect the pre-imaginal development and reproduction of H. axyridis. The development of the pre-imaginal stage was significantly faster at shorter photoperiods (0–14?h) than at longer ones (16–24?h). The proportion of females laying eggs within the first 30 days after eclosion, the mean number of eggs per ovipositing female, and the long axial length of the first oocyte were all lower at shorter photoperiods (6–12?h) than at longer ones (14–24?h). These results suggest that adult H. axyridis may encounter problems in preying and reproducing in the winter conditions of unheated and unilluminated greenhouses in areas with temperatures lower than 20°C and day lengths shorter than 12?h. 相似文献
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Takeo Deguchi 《Molecular and cellular biochemistry》1979,27(1):57-66
Conclusion The circadian rhythm of melatonin synthesis in the pineal glands of various species has been summarized. The night-time elevation of melatonin content is in most if not all cases regulated by the change of N-acetyltransferase activity. In mammals, the N-acetyltransferase rhythm is controlled by the central nervous system, presumably by suprachiasmatic nuclei in hypothalamus through the superior cervical ganglion. In birds, the circadian oscillator that regulates the N-acetyltransferase rhythm is located in the pineal glands. The avian pineal gland may play a biological clock function to control the circadian rhythms in physiological, endocrinological and biochemical processes via pineal hormone melatonin. 相似文献
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Junjie Ying Zhou Jiang Lu Ding Wang Hou Xiaoxue Li Fang Qi 《Biological Rhythm Research》2018,49(1):39-49
Transactivator (Tat), a regulatory protein of HIV-1, plays a very important role in HIV-1 infection by promoting the rapid replication of HIV. Research surrounding Tat protein function has mainly focused on inhibition of the immune system, promotion of growth of vascular endothelial cells, and nervous system damage. To date, very little research has addressed the role of Tat in circadian rhythms. Previous studies in our lab have found that the concentration of Tat protein in HIV patients’ blood was positively correlated with patients’ sleep quality and melatonin concentrations. In this study, we applied a Tat expression plasmid in mice. Result demonstrated that the locomotor activities of mice and the concentration of melatonin were significantly increased. Alternatively, the expression of Clock gene was markedly decreased. On the other hand, the expression of the Cry1 gene was significantly increased, while the expression of Bmal1 and Per1 genes exhibited no significant difference. 相似文献
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Ehab HASSANEEN Alaa El‐Din SALLAM Ahmad ABO‐GHALIA Yoshiyuki MORIYAMA Kenji TOMIOKA 《Entomological Science》2011,14(3):278-282
Pigment‐dispersing factor (PDF) is an important neurotransmitter in insect circadian systems. In the cricket Gryllus bimaculatus, it affects nocturnal activity, the free‐running period and photic entrainment. In this study, to investigate whether these effects of PDF occur through a circadian molecular machinery, we measured mRNA levels of clock genes period (per) and timeless (tim) in crickets with pdf expression knocked‐down by pdf RNAi. The pdf RNAi decreased per and tim mRNA levels during the night to reduce the amplitude of their oscillation. The phase of the rhythm advanced by about 4 h in terms of trough and/or peak phases. On the other hand, pdf mRNA levels were little affected by per and tim RNAi treatment. These results suggest that PDF affects the circadian rhythm at least in part through the circadian molecular oscillation while the circadian clock has little effect on the pdf expression. 相似文献
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Locomotor activity rhythm was examined at various temperatures under a 16 h light : 8 h dark photoperiod (LD 16:8) or LD 12:12 using adults of the burying beetle Nicrophorus quadripunctatus. At 20°C, the locomotor activity of the beetles showed a bimodal daily pattern with two peaks around lights on and lights off under both photoperiods. This bimodal activity rhythm persisted under constant darkness; therefore, the activity of adult N. quadripunctatus is controlled by a circadian clock. Adults showed a bimodal activity pattern for temperatures ranging from 15 to 25°C. The evening peak of the daily activity was earlier at lower temperatures. These findings suggest that in the field, N. quadripunctatus shows crepuscular activity, and is active earlier in the afternoon in cooler seasons. In this species, therefore, temperature appears to play an important role in the determination of daily activity patterns. 相似文献
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OsPRR37 confers an expanded regulation of the diurnal rhythms of the transcriptome and photoperiodic flowering pathways in rice 下载免费PDF全文
Chuan Liu Xuefeng Qu Yanhao Zhou Gaoyuan Song Naghmeh Abiri Yuhui Xiao Fan Liang Daiming Jiang Zhongli Hu Daichang Yang 《Plant, cell & environment》2018,41(3):630-645
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KATHERINE A. BEAUCHAMP 《Invertebrate reproduction & development.》2013,57(2-3):171-182
Summary Males of Balanophyllia elegans Verrill, 1864 in Monterey Bay, California, spawn in the fall. Fertilization occurs within the females and the internally brooded embryos develop into large benthic planulae that are released mainly in the late winter. Field-collected corals were held in the laboratory under contrasting photoperiod regimes (ambient or in-phase, and 6 months out-of-phase) for 6.5 years. After two years in the laboratory corals planulated at the same time, independent of photoperiod. Corals show a cyclic pattern of later winter and early spring planulation that coincides with declining sea temperatures in Monterey Bay. Gametes appeared in the first laboratory generation at IS months and brooded embryos were found in females at 31 months under both light regimes. Planulae production by laboratory-reared corals peaked at the same time as that of the parents. These findings suggest that the temporal pattern of planulation is regulated by both endogenous and exogenous components that can be modified in some way by disturbance caused to the corals when collected or by the time of collection. 相似文献
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昆虫生物钟分子调控研究进展 总被引:3,自引:2,他引:1
昆虫生物钟节律的研究是人类了解生物节律的重要途径。昆虫在生理和行为上具有广泛的节律活动,如运动、睡眠、学习记忆、交配、嗅觉等节律活动,其中昼夜活动行为节律的研究广泛而深入。昆虫乃至高等动物普遍具有保守的昼夜节律系统,昼夜生物钟节律主要包括输入系统:用于接受外界光和温度等环境信号并传入核心振荡器,使得生物时钟与环境同步;核心时钟系统:自我维持的昼夜振荡器;输出系统:将生物钟产生的信号传递出去而控制生物行为和生理的节律变化。早期分子和遗传学研究主要关注昼夜节律振荡器的分子机制及神经生物学,阐明了昼夜生物钟节律的主要分子机制及相关神经网络。最近更多的研究关注生物钟信号是如何输入和输出。本文以果蝇运动节律的相关研究为主要内容,围绕生物钟输入系统、振荡器、输出系统这3个组成部分对昆虫生物钟研究进展进行总结。 相似文献
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S. Bohlken J. Joosse R. van Elk W. P.M. Geraerts 《Invertebrate reproduction & development.》2013,57(2):151-157
Summary A study was made of the interaction of the photoperiod and the availability of food in influencing egg laying of the freshwater snail Lymnaea stagnalis. At a long day photoperiod (LD = 16 h light/8 h dark) egg laying of fed snails had increased compared with that of fed animals kept at a medium day photoperiod (MD = 12 h light/12 h dark). In MD snails oviposition ceased within a week of the beginning of a starvation period. This is most probably due to a reduction in the activities of the neuroendocrine caudodorsal cells which secrete an ovulation hormone. In contrast, in starved LD snails a low rate of ovipository activity continued, indicating that a lowered frequency of caudodorsal cell release cycles occurred under these conditions. The decreased mean size (number of eggs) of the egg masses in starved LD snails indicates that the activities of the endocrine dorsal bodies, which control vitellogenesis and synthetic activities in the female accessory sex organs, had decreased. All MD snails survived, but nearly all LD snails died during the course of the experiment. Determinations of the mantle glycogen stores of LD snails suggest that the high mortality of LD snails is due to exhaustion of the animal's energy reserves. 相似文献