Éléments méthodologiques complémentaires dans l'analyse des rythmes : recherche de périodes, modélisation. Exemples de la Mélatonine plasmatique et de courbes de températures

Gouthière, L.; Bruno, Claudio; Brun, Julien; Mauvieux, Benoît

doi:10.1016/j.patbio.2004.12.025

Cited by 14 publications

(10 citation statements)

References 2 publications

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“…Chronobiological analyses were performed using the software Time Series Analysis Serie Cosinor 6.3 (http://www.euroestech.com). Data were processed and analyzed to validate a rhythm in oysters [23,24]. Briefly, the quality of the data set was assessed by controlling the absence of randomness using the autocorrelation diagram and the absence of a stationary character by a Partial Autocorrelation Function (PACF) calculation [25].…”

Section: Methodsmentioning

confidence: 99%

“…When a period was statistically validated, rhythmicity was modeled with the Cosinor model, which used a cosine function calculated by regression [28,29]. The model for a given period was written as: Y(t) = A.cos(2πt/τ + φ) + M + ϵ(t) where A was the amplitude, φ the acrophase, τ the period, M the mesor and ϵ the relative error [24]. Two tests provided the validation of the model: the elliptic test [29] had to be rejected and the probabilities ( p -value) for the null amplitude hypothesis had to be lower than 0.05.…”

Section: Methodsmentioning

confidence: 99%

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Identification of the Molecular Clockwork of the Oyster Crassostrea gigas

Perrigault

Tran

2017

PLoS ONE

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Molecular clock system constitutes the origin of biological rhythms that allow organisms to anticipate cyclic environmental changes and adapt their behavior and physiology. Components of the molecular clock are largely conserved across a broad range of species but appreciable diversity in clock structure and function is also present especially in invertebrates. The present work aimed at identify and characterize molecular clockwork components in relationship with the monitoring of valve activity behavior in the oyster Crassostrea gigas. Results provided the characterization of most of canonical clock gene including clock, bmal/cycle, period, timeless, vertebrate-type cry, rev-erb, ror as well as other members of the cryptochrome/photolyase family (plant-like cry, 6–4 photolyase). Analyses of transcriptional variations of clock candidates in oysters exposed to light / dark regime and to constant darkness led to the generation of a putative and original clockwork model in C. gigas, intermediate of described systems in vertebrates and insects. This study is the first characterization of a mollusk clockwork. It constitutes essential bases to understand interactions of the different components of the molecular clock in C. gigas as well as the global mechanisms associated to the generation and the synchronization of biological rhythms in oysters.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Identification of the Molecular Clockwork of the Oyster Crassostrea gigas

Perrigault

Tran

2017

PLoS ONE

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“…Both Temp and Act data obtained from each rat during control conditions and following transtympanic injection were used to calculate the different parameters of the daily rhythms (period, amplitude, acrophase, and mesor) using Times Series Analysis Serial Cosinor 6.3 (www.euroestech.net) software (TSA) following the procedure established by Gouthiere et al (20).…”

Section: Analysis Of Daily Rhythmsmentioning

confidence: 99%

Vestibular loss disrupts daily rhythm in rats

Martin

Mauvieux

Bulla

et al. 2015

Journal of Applied Physiology

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Hypergravity disrupts the circadian regulation of temperature (Temp) and locomotor activity (Act) mediated through the vestibular otolithic system in mice. In contrast, we do not know whether the anatomical structures associated with vestibular input are crucial for circadian rhythm regulation at 1 G on Earth. In the present study we observed the effects of bilateral vestibular loss (BVL) on the daily rhythms of Temp and Act in semipigmented rats. Our model of vestibular lesion allowed for selective peripheral hair cell degeneration without any other damage. Rats with BVL exhibited a disruption in their daily rhythms (Temp and Act), which were replaced by a main ultradian period ( Ͻ20 h) for 115.8 Ϯ 68.6 h after vestibular lesion compared with rats in the control group. Daily rhythms of Temp and Act in rats with BVL recovered within 1 wk, probably counterbalanced by photic and other nonphotic time cues. No correlation was found between Temp and Act daily rhythms after vestibular lesion in rats with BVL, suggesting a direct influence of vestibular input on the suprachiasmatic nucleus. Our findings support the hypothesis that the vestibular system has an influence on daily rhythm homeostasis in semipigmented rats on Earth, and raise the question of whether daily rhythms might be altered due to vestibular pathology in humans. vestibular system; biological rhythms; temperature; locomotor activity; rats LOCATED IN THE TEMPORAL BONES, the vestibular system is composed of three semicircular canals that encode head rotation velocity and two otolithic macula that encode linear acceleration and gravity force. The vestibular system is primarily involved in gaze stabilization and postural control (23), but its influence has been expanded to autonomic and bone regulation (11,61,63), spatial learning and memory (5, 6, 56), and spatial orientation and perception of gravitational verticality (37). Studies carried out in environments in which gravity is altered have shown evidence of a possible influence of the vestibular system on hypothalamic circadian function in rats (27) and mice (18,46

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“…Different steps were performed to validate a rhythm in the scallops204546. Briefly, the quality of the data set was assessed by controlling for the absence of randomness using the autocorrelation diagram and the absence of a stationary character using a partial autocorrelation function (PACF) calculation47.…”

Section: Methodsmentioning

confidence: 99%

“…When a period was statistically validated, the rhythmicity was modelled using the Cosinor model, which uses a cosine function calculated by a regression5051. The model for a given period is written as: Y(t) = A.cos(2πt/τ + φ) + M + ϵ(t), where A is the amplitude, φ is the acrophase, τ is the period, M is the mesor, and ϵ is the relative error45. To validate the model, two tests were performed: the elliptic test51, must which must be rejected, and the probabilities ( p -value) for the null amplitude hypothesis, which must be lower than 0.05.…”

Section: Methodsmentioning

confidence: 99%

In the darkness of the polar night, scallops keep on a steady rhythm

Tran

Sow

Camus

et al. 2016

Sci Rep

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Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animal’s behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists throughout the polar night and lasts for at least 4 months. Based on observations across three polar nights, we showed that the robustness and synchronicity of the rhythm depends on the angle of the sun below the horizon. The weakest rhythm occurred at the onset of the polar night during the nautical twilight. Surprisingly, the circadian behaviour began to recover during the darkest part of the polar night. Because active rhythms optimize the fitness of an organism, our study brings out that the scallops C. islandica remain active even during the polar night.

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Éléments méthodologiques complémentaires dans l'analyse des rythmes : recherche de périodes, modélisation. Exemples de la Mélatonine plasmatique et de courbes de températures

Cited by 14 publications

References 2 publications

Identification of the Molecular Clockwork of the Oyster Crassostrea gigas

Identification of the Molecular Clockwork of the Oyster Crassostrea gigas

Vestibular loss disrupts daily rhythm in rats

In the darkness of the polar night, scallops keep on a steady rhythm

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