Abstract：
:We examine theoretical models for circadian oscillations based on transcriptional regulation in Drosophila and Neurospora. For Drosophila, the molecular model is based on the negative feedback exerted on the expression of the per and tim genes by the complex formed between the PER and TIM proteins. For Neurospora, similarly, the model relies on the feedback exerted on the expression of the frq gene by its protein product FRQ. In both models, sustained rhythmic variations in protein and mRNA levels occur in continuous darkness, in the form of limit cycle oscillations. The effect of light on circadian rhythms is taken into account in the models by considering that it triggers degradation of the TIM protein in Drosophila, and frq transcription in Neurospora. When incorporating the control exerted by light at the molecular level, we show that the models can account for the entrainment of circadian rhythms by light-dark cycles and for the damping of the oscillations in constant light, though such damping occurs more readily in the Drosophila model. The models account for the phase shifts induced by light pulses and allow the construction of phase response curves. These compare well with experimental results obtained in Drosophila. The model for Drosophila shows that when applied at the appropriate phase, light pulses of appropriate duration and magnitude can permanently or transiently suppress circadian rhythmicity. We investigate the effects of the magnitude of light-induced changes on oscillatory behavior. Finally, we discuss the common and distinctive features of circadian oscillations in the two organisms.
journal_name
J Biol Rhythmsjournal_title
Journal of biological rhythmsauthors
Leloup JC,Gonze D,Goldbeter Adoi
10.1177/074873099129000948subject
Has Abstractpub_date
1999-12-01 00:00:00pages
433-48issue
6eissn
0748-7304issn
1552-4531journal_volume
14pub_type
杂志文章,评审abstract：:Nonphotic stimuli can reset and entrain circadian activity rhythms in hamsters and mice, and serotonin is thought to be involved in the phase-resetting effects of these stimuli. In the present study, the authors examined the effect of the serotonin agonist quipazine on circadian activity rhythms in three inbred strain...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873099129000524
更新日期：1999-04-01 00:00:00
abstract：:Individuals of the shore crab Carcinus maenas were exposed to artificial cycles, applied in tidal antiphase, of pairs of the three major environmental variables that entrain circatidal rhythmicity in this species: salinity, temperature, and hydrostatic pressure. During entrainment, the observed locomotor activity patt...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873049000500405
更新日期：1990-01-01 00:00:00
abstract：:The Drosophila clock relies on transcriptional feedback loops that generate daily oscillations of the clock gene expression at mRNA and protein levels. In the evening, the CLOCK (CLK) and CYCLE (CYC) basic helix-loop-helix (bHLH) PAS-domain transcription factors activate the expression of the period (per) and timeless...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730407313817
更新日期：2008-04-01 00:00:00
abstract：:The circadian pacemaker of the SCN is a heterogeneous structure containing many single-cell oscillators that display phase differences in gene expression and electrical activity rhythms. Thus far, it is unknown how single neurons contribute to the population signal measured from the SCN. The authors used single-unit e...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730406290317
更新日期：2006-08-01 00:00:00
abstract：:How the cellular elements of the SCN are synchronized to each other is not well understood. We explore circadian oscillations manifest at the level of the cell, the tissue, and the whole animal to better understand intra-SCN synchrony and master clock function of the nucleus. At each level of analysis, responses to va...
journal_title：Journal of biological rhythms
pub_type： 杂志文章,评审
doi：10.1177/0748730409344800
更新日期：2009-10-01 00:00:00
abstract：:Siberian hamsters (Phodopus sungorus) exhibit changes in immune function following adaptation to short photoperiods, including a marked attenuation of energetically expensive thermoregulatory and behavioral responses to gram-negative bacterial infections. Whether this seasonal attenuation of the immune response is idi...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730407311518
更新日期：2008-02-01 00:00:00
abstract：:Access to electric light might have shifted the ancestral timing and duration of human sleep. To test this hypothesis, we studied two communities of the historically hunter-gatherer indigenous Toba/Qom in the Argentinean Chaco. These communities share the same ethnic and sociocultural background, but one has free acce...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730415590702
更新日期：2015-08-01 00:00:00
abstract：:Many mammalian cell types show daily rhythms in gene expression driven by a circadian pacemaker. For example, cultured astrocytes display circadian rhythms in Period1 and Period2 expression. It is not known, however, how or which intercellular factors synchronize and sustain rhythmicity in astrocytes. Because astrocyt...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730409332042
更新日期：2009-04-01 00:00:00
abstract：:Surgical isolation of the suprachiasmatic nuclei (SCN) within a hypothalamic island is reported to produce loss of circadian rhythmicity. The results have been interpreted to indicate that SCN efferents are necessary for the expression of circadian rhythms. It is not clear, however, whether the loss of circadian rhyth...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873049100600201
更新日期：1991-07-01 00:00:00
abstract：:The role of the intergeniculate leaflet of the thalamus (IGL) in photoperiod responsiveness was examined in a laboratory-selected line of photoperiod nonresponsive (NR) Siberian hamsters. NR hamsters fail to exhibit typical winter-type responses (i.e., gonadal regression and development of winter-type pelage) when exp...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730406287996
更新日期：2006-06-01 00:00:00
abstract：:Mice homozygous for a dominant-negative allele of the Clock gene (Clock (Δ19/Δ19)) have slightly but significantly decreased male fertility. The molecular mechanism for this reduction in fertility is unknown. In the present study, we used a small hairpin RNA (shRNA) strategy to specifically knock down the Clock gene e...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730413486873
更新日期：2013-06-01 00:00:00
abstract：:A single light episode during the first larval stage can set the phase of adult Drosophila activity rhythms, showing that a light-sensitive circadian clock is functional in larvae and is capable of keeping time throughout development. These behavioral data are supported by the finding that neurons expressing clock pro...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730403260621
更新日期：2004-02-01 00:00:00
abstract：:Transplantation of the fetal suprachiasmatic nucleus (SCN) in arrhythmic SCN-lesioned rats can reinstate circadian drinking rhythms in 40% to 50% of the cases. In the current article, it was investigated whether the failure in the other rats could be due to the absence of a circadian rhythm in the grafted SCN, using a...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873099129000416
更新日期：1999-02-01 00:00:00
abstract：:A gradual adaptation to a shifted light-dark (LD) cycle is a key element of the circadian clock system and believed to be controlled by the central circadian pacemaker, the suprachiasmatic nucleus (SCN). Endocrine factors have a strong influence on the regulation of the circadian clock network and alter acute photic r...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730420965291
更新日期：2020-12-01 00:00:00
abstract：:Perhaps the most observable of the many circadian oscillations that have been described in both vertebrate and invertebrate animals is the daily alterations in periods of rest and activity. Recent studies in the fruit fly Drosophila melanogaster suggest that these periods of inactivity are not simply rest but share ma...
journal_title：Journal of biological rhythms
pub_type： 杂志文章,评审
doi：10.1177/0748730402239672
更新日期：2003-02-01 00:00:00
abstract：:Circadian rhythms are programmed by the suprachiasmatic nucleus (SCN), which relies on neuropeptide signaling to maintain daily timekeeping. Vasoactive intestinal polypeptide (VIP) is critical for SCN function, but the precise role of VIP neurons in SCN circuits is not fully established. To interrogate their contribut...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730420925573
更新日期：2020-08-01 00:00:00
abstract：:Almost exclusively, photoperiodic insects respond to a given photoperiod in one of two ways: a "long-day" response or a "short-day" response. Intermediate responses occur only at a very restricted range of photoperiods (often less than 30 min) and are generally population phenomena rather than intermediate responses o...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873049300800104
更新日期：1993-04-01 00:00:00
abstract：:Despite the omnipresence of artificial and natural light exposure, there exists little guidance in the United States and elsewhere on light exposure in terms of timing, intensity, spectrum, and other light characteristics known to affect human health, performance, and well-being; in parallel, there is little informati...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730418789506
更新日期：2018-10-01 00:00:00
abstract：:The aim of this study was to replicate and extend previous work in which the authors observed lower, shorter, and advanced nocturnal melatonin secretion patterns in premenstrually depressed patients compared to those in healthy control women. The authors also sought to test the hypothesis that the therapeutic effect o...
journal_title：Journal of biological rhythms
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1177/074873049701200107
更新日期：1997-02-01 00:00:00
abstract：:Threads of evidence from recent experimentation in retinal morphology, neurochemistry, electrophysiology, and visual perception point toward rhythmic ocular processes that may be integral components of circadian entrainment in mammals. Components of retinal cell biology (rod outer-segment disk shedding, inner-segment ...
journal_title：Journal of biological rhythms
pub_type： 杂志文章,评审
doi：10.1177/074873049100600104
更新日期：1991-04-01 00:00:00
abstract：:The hypothalamic suprachiasmatic nucleus (SCN), a circadian pacemaker, is present in all mammalian brains. It has a complex organization of peptide-containing neurons that is similar among species, but calcium-binding proteins are expressed variably. Neurons containing calretinin have been described in the SCN in a nu...
journal_title：Journal of biological rhythms
pub_type： 信件
doi：10.1177/0748730416654024
更新日期：2016-08-01 00:00:00
abstract：:The light preferences of fruit flies were tested by 2 different means. First, flies were allowed to choose between different illuminations, and their favorite resting, grooming, and feeding places were determined with an infrared-sensitive camera. Second, the activity levels of the animals during their main daily acti...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730407306198
更新日期：2007-10-01 00:00:00
abstract：:The tau mutation in Syrian hamsters (Mesocricetus auratus) is phenotypically expressed in a period of the circadian rhythm of about 20 h in homozygotes (SS) and about 22 h in heterozygotes (S+). The authors investigate whether this well-defined model for variation in circadian period exhibits associated changes in ene...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873049701200503
更新日期：1997-10-01 00:00:00
abstract：:Over 90% of neurons within the suprachiasmatic nucleus (SCN) express γ-aminobutyric acid (GABA). Although GABA is primarily an inhibitory neurotransmitter, in vitro studies suggest that the activation of GABAA receptors (GABAAR) elicits excitation in the adult SCN. The ratio of excitatory to inhibitory responses to GA...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730418782820
更新日期：2018-08-01 00:00:00
abstract：:To assess binocular interactions and possible ocular dominance in entrainment of circadian rhythms, Syrian hamsters maintained in LL were subjected for several weeks to schedules of eye occlusion with opaque contact lenses. In separate groups, the opaque lens was inserted into the left or right eye for 12 h at the sam...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730404272967
更新日期：2005-02-01 00:00:00
abstract：:The synchronizing stimulus, its transduction site, and the afferent pathways responsible for feeding entrainment remain unknown. In fish, the role of the diet in the development of feeding anticipatory activity (FAA) is not well understood and fundamental questions on the mechanisms of feeding entrainment, such as the...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873040101600107
更新日期：2001-02-01 00:00:00
abstract：:The adjustment of hamsters to advanced light-dark (LD) cycles can be greatly accelerated by scheduling a single 3-hr bout of extra activity in a novel running wheel, starting about 7 hr before the time when the animals become active in the preceding LD cycle. The present experiments were designed to provide stronger e...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873048900400305
更新日期：1989-10-01 00:00:00
abstract：:Drosophila littoralis is a latitudinally widespread European species of the Drosophila virilis group. The species has ample genetic variation in photoperiodism (adult diapause) and circadian rhythmicity (pupal eclosion rhythm), with adaptive latitudinal clines in both of them. The possible common genetic basis between...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/0748730405283418
更新日期：2006-02-01 00:00:00
abstract：:Austrovenus stutchburyi is an intertidal, burrowing, filter-feeding bivalve. It exhibits a strong, approximately tidal pattern in the time of gaping of its valves when in constant laboratory conditions. Individuals that have been held in laboratory conditions long enough to lose their overt gaping pattern will respond...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873049701200208
更新日期：1997-04-01 00:00:00
abstract：:The possibility that feeding may act as a zeitgeber has been investigated in captive Svalbard ptarmigan by recording feeding or food-searching activity (FA) in birds given periodic access to food (PAF) under light-dark (LD) cycles or in continuous bright (LL) or dim light (DD) conditions. Except during LL, anticipator...
journal_title：Journal of biological rhythms
pub_type： 杂志文章
doi：10.1177/074873049801300504
更新日期：1998-10-01 00:00:00
