Formal Properties of the Circadian and Photoperiodic Systems of Japanese Quail: Phase Response Curve and Effects of T-Cycles

Zivkovic, Bora; Underwood, Herbert; Steele, Christopher T.; Edmonds, Kent E.

doi:10.1177/074873099129000786

Cited by 8 publications

(3 citation statements)

References 25 publications

(44 reference statements)

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“…Environmental cycles of varying durations (T cycles) have been used to test the role of a circadian clock in animal photoperiodism. In quails or hamsters, entrainment to varying T cycles altered the phase of circadian rhythms relative to light and darkness, and these effects varied in parallel with those on gonadal development (23,24).…”

Section: Effects Of Varying the Total Duration Of The Light͞dark Cyclementioning

confidence: 99%

Floral responses to photoperiod are correlated with the timing of rhythmic expression relative to dawn and dusk inArabidopsis

Roden

Song

Jackson

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

109

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Daylength, or photoperiod, is perceived as a seasonal signal for the control of flowering of many plants. The measurement of daylength is thought to be mediated through the interaction of phototransduction pathways with a circadian rhythm, so that flowering is induced (in long-day plants) or repressed (in short-day plants) when light coincides with a sensitive phase of the circadian cycle. To test this hypothesis in the facultative long-day plant, Arabidopsis thaliana, we used varying, non-24-hr light͞dark cycles to alter the timing of circadian rhythms of gene expression relative to dawn and dusk. Effects on circadian rhythms were correlated with those on flowering times. We show that conditions that displaced subjective night events, such as expression of the flowering time regulator CONSTANS into the light portion of the cycle, were perceived as longer days. This work demonstrates that the perception of daylength in Arabidopsis relies on adjustments of the phase angle of circadian rhythms relative to the light͞dark cycle, rather than on the measurement of the absolute duration of light and darkness.T he sexual reproduction of many plants and animals occurs on a seasonal basis and is triggered by changes in daylength, or photoperiod. In plants, floral responses to photoperiod vary widely between species and have been classified into three broad categories. Short-day plants are induced to flower when the photoperiod is shorter than a critical daylength, whereas longday plants flower under photoperiods that are longer than their critical daylength; day-neutral plants are insensitive to photoperiod.Measurement of day-or night-length could, in theory, be performed by an hourglass-type of timer, measuring time from either dawn or dusk, or even the relative amounts of light and darkness. For example, flowering of cocklebur (Xanthium) is essentially determined by the absolute duration of darkness (1, 2), and induction of diapause in the aphid Megoura viciae relies on measuring time from dusk (3). However, the total duration of light or darkness was not the critical factor determining the response in other plant and animal species. For example, when Japanese morning glory (Ipomea nil, also described as Pharbitis nil) were transferred to extended nights, appropriately timed night breaks mimicked the effects of long days and inhibited flowering (4). Remarkably, sensitivity to night breaks varied with a 24-hr period. Gonadal development in birds and induction of diapause in insects also exhibited rhythmic responsiveness to short light signals in constant darkness (3, 5).These and other similar findings (reviewed in ref.2) suggested that photoperiodic time measurement may involve a circadian rhythm of responsiveness to light, known as the photoperiodic response rhythm (6). Two possible mechanisms have been proposed, by which a circadian clock might mediate perception of photoperiod (7). According to the external coincidence model, a photoperiodic response may be induced when an external signal (light) coincides with a pho...

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Section: Effects Of Varying the Total Duration Of The Light͞dark Cyclementioning

confidence: 99%

Floral responses to photoperiod are correlated with the timing of rhythmic expression relative to dawn and dusk inArabidopsis

Roden

Song

Jackson

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

109

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“…In particular, interactions between circadian and other oscillatory processes may invalidate the results of analyses conducted with exclusive focus on circadian rhythmicity. Empirical research has documented interactions of circadian rhythmicity with tidal rhythmicity (Akiyama 2004;Barnwell 1968;de la Iglesia et al 1994;Palmer 1967;Stillman & Barnwell 2004;Wikelski & Hau 1995), reproductive rhythmicity (Häster & Erkert 1993;Houdelier et al 2002;Kadono et al 1981;Rauth-Widmann et al 1996;Zivkovic et al 1999), weekly rhythmicity (Cornélissen et al 1986;Fálcon et al 1996;Sanchez de la Peña et al 1983;Schweiger et al 1986), and annual rhythmicity (Bertolucci et al 2002;Honma et al 1992;Lee & Zucker 1995;Menaker 1961;Mrosovsky et al 1976;Wollnik & Schmidt 1995), among others.…”

Section: Introductionmentioning

confidence: 99%

Procedures for numerical analysis of circadian rhythms

Refinetti

Lissen

Halberg

2007

Biological Rhythm Research

596

486

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“…The light information is transmitted to the circadian system via photoreceptors situated in the retina, the pineal gland or dispersed in the brain (Pang et al, 1996) to synchronise the oscillator system with exogenous conditions. In constant light, the continuous attempt to synchronise could lead to a temporal disorganisation of the behavioural output (Binkley, 1977), all the more so since the phase response curve in quail is continuous (Zivkovic et al, 1999). Thus, light could act firstly on the coupling between the input pathway and the pacemakers.…”

Section: Discussionmentioning

confidence: 99%

Effect of Light Intensity on Circadian Activity in Developing Japanese Quail

Lumineau¹,

Guyomarc’h²

2003

Biological Rhythm Research

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The effects of constant light on the expression of the circadian rhythm of feeding activity in Japanese quail, and in particular on the clarity of the rhythm were investigated. We used 46 4-week-old birds (35 females and 11 males) issued from two lines selected for a more (line R: 25 females and 10 males) or less (line A: 10 females and 1 male) clear circadian rhythm of feeding activity. The birds, were placed successively under three light schedules: constant darkness (DD), constant dim green light (LLdim) and constant bright light (LLbright). Schedules were changed every 2 weeks. Feeding activity was recorded continuously, analysed by autocorrelation and spectral analysis, and the ratio of the correlation coefficients and the area of the spectrum peak were used as indexes to quantify the clarity of the circadian rhythm.During the experiment, some birds showed gonadal development. Therefore, we analysed separately birds showing either a high or low degree of sexual development at the end of the experiment. In DD, 35 birds showed a circadian feeding rhythm with a mean period of 22.5 ± 0.1 h, whereas 11 birds showed an arrhythmic activity. In LLdim, 27 birds were rhythmic (22 birds R and 5 birds A), and in LLbright, only 3 birds showed a rhythmic circadian activity. For the R-line birds (for females and males), the rhythm clarity decreased in LLdim compared to DD, except for the not developed females. For the A-line birds (for females), the rhythm clarity of the immature birds increased in LLdim and that of the developed birds remained stable. In LLbright, circadian activity became arrhythmic. In LLdim, the active phases of 12 birds showed two main peaks, with mean periods of 22.7 h and 25.1 h, respectively. Therefore, constant light appeared to have an inhibitory effect on the expression of the circadian rhythm. We postulate that two hierarchically coupled oscillators could control circadian feeding activity, and arrhythmia in LLbright could be the results of internal desynchronization of the pacemakers.

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Formal Properties of the Circadian and Photoperiodic Systems of Japanese Quail: Phase Response Curve and Effects of T-Cycles

Cited by 8 publications

References 25 publications

Floral responses to photoperiod are correlated with the timing of rhythmic expression relative to dawn and dusk inArabidopsis

Floral responses to photoperiod are correlated with the timing of rhythmic expression relative to dawn and dusk inArabidopsis

Procedures for numerical analysis of circadian rhythms

Effect of Light Intensity on Circadian Activity in Developing Japanese Quail

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