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Journal articles on the topic 'Circadian systems'

Author: Grafiati

Published: 5 April 2025

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1

Roenneberg, Till, and Martha Merrow. "Circadian systems: different levels of complexity." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 356, no. 1415 (November 29, 2001): 1687–96. http://dx.doi.org/10.1098/rstb.2001.0969.

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After approximately 50 years of circadian research, especially in selected circadian model systems ( Drosophila, Neurospora, Gonyaulax and, more recently, cyanobacteria and mammals), we appreciate the enormous complexity of the circadian programme in organisms and cells, as well as in physiological and molecular circuits. Many of our insights into this complexity stem from experimental reductionism that goes as far as testing the interaction of molecular clock components in heterologous systems or in vitro . The results of this enormous endeavour show circadian systems that involve several oscillators, multiple input pathways and feedback loops that contribute to specific circadian qualities but not necessarily to the generation of circadian rhythmicity. For a full appreciation of the circadian programme, the results from different levels of the system eventually have to be put into the context of the organism as a whole and its specific temporal environment. This review summarizes some of the complexities found at the level of organisms, cells and molecules, and highlights similar strategies that apparently solve similar problems at the different levels of the circadian system.

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2

Schulz, Pierre, and Thierry Steimer. "Neurobiology of Circadian Systems." CNS Drugs 23, Supplement 2 (September 2009): 3–13. http://dx.doi.org/10.2165/11318620-000000000-00000.

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3

Foster, Russell G. "Photoreceptors and Circadian Systems." Current Directions in Psychological Science 2, no. 2 (April 1993): 34–39. http://dx.doi.org/10.1111/1467-8721.ep10770677.

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4

Roenneberg, Till, and Martha Merrow. "Circadian Systems and Metabolism." Journal of Biological Rhythms 14, no. 6 (December 1999): 449–59. http://dx.doi.org/10.1177/074873099129001019.

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5

Lee, Junghyun, Sevde Goker, Sookkyung Lim, and Christian I. Hong. "Development of circadian rhythms in mammalian systems." Biochemical Journal 481, no. 24 (December 23, 2024): 1967–76. https://doi.org/10.1042/bcj20210060.

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In mammals, molecular mechanisms of circadian rhythms involve a time-delayed negative feedback loop generating autonomous oscillations of ∼24 h. Most cell types in mammals possess circadian rhythms regulating temporal organization of cellular and physiological processes. Intriguingly, pluripotent stem cells do not possess circadian rhythms and oscillations arise after a defined period of differentiation. Previous studies demonstrated that post-transcriptional regulations of core clock components, CLOCK and PER2, play critical roles in inducing circadian rhythms. In this article, we review the development of circadian rhythms in mammalian systems and provide a theoretical understanding of potential mechanisms regulating the birth of circadian rhythms using mathematical modeling.

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Kalustova, D., V. Kornaga, A. Rybalochka, and S. Valyukh. "Space of visual and circadian parameters of RGBW lighting systems." Lighting engineering and power engineering 1, no. 57 (April 6, 2020): 16–21. http://dx.doi.org/10.33042/2079-424x-2020-1-57-16-21.

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Due to the proven effect of light on human circadian rhythms, nowadays researchers and developers of lighting systems (LS) concentrate on the non-visual parameters of light and methods of ensuring a safe comfortable light environment. This requires optimisation of spectral power distribution (SPD). In this view the most promising and functional are RGBW systems due to their ability to change dynamically SPD and, hence, light parameters. In this work we explore two RGBW (red-greenblue-white) systems with different white LEDs (warm white and neutral white) and the space of visual and non-visual parameters that they can ensure. Visual parameters are studied in terms of colour rendering index, colour fidelity index and visual corneal illuminance while non-visual parameters are studied in terms of circadian light, circadian stimulus and circadian action factor. These parameters are calculated for different contribution of the components in a correlated colour temperature (CCT) range of 2500 – 7000K. In addition, acceptable criterion of the colour fidelity index above 85 is used. It is shown that under this condition the circadian action factor in the range of 0.33-0.98 can be obtained by changing the CCT and (or) colour fidelity index. Also an achievable area of the circadian stimulus versus corneal illuminance space for RGBW systems is found. It enables to choose optimal combination of CCT, circadian stimulus and corneal illuminance to provide the desired level of circadian effect with sufficient visual comfort depending on the daytime and field of system's implementation. This data is useful for LS manufacturers and lighting designers to create a comfortable lighting environment. Keywords - RGBW colour mixing, tunable white light, circadian effect, colour rendering, colour fidelity index.

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Hubbard, Katharine E., Fiona C. Robertson, Neil Dalchau, and Alex A. R. Webb. "Systems analyses of circadian networks." Molecular BioSystems 5, no. 12 (2009): 1502. http://dx.doi.org/10.1039/b907714f.

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8

Lin, L. L., H. C. Huang, and H. F. Juan. "Circadian systems biology in Metazoa." Briefings in Bioinformatics 16, no. 6 (March 10, 2015): 1008–24. http://dx.doi.org/10.1093/bib/bbv006.

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9

Neumann, Anne-Marie, Cosima Xenia Schmidt, Ruth Merle Brockmann, and Henrik Oster. "Circadian regulation of endocrine systems." Autonomic Neuroscience 216 (January 2019): 1–8. http://dx.doi.org/10.1016/j.autneu.2018.10.001.

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10

Tsang, Anthony H., Johanna L. Barclay, and Henrik Oster. "Interactions between endocrine and circadian systems." Journal of Molecular Endocrinology 52, no. 1 (August 30, 2013): R1—R16. http://dx.doi.org/10.1530/jme-13-0118.

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In most species, endogenous circadian clocks regulate 24-h rhythms of behavior and physiology. Clock disruption has been associated with decreased cognitive performance and increased propensity to develop obesity, diabetes, and cancer. Many hormonal factors show robust diurnal secretion rhythms, some of which are involved in mediating clock output from the brain to peripheral tissues. In this review, we describe the mechanisms of clock–hormone interaction in mammals, the contribution of different tissue oscillators to hormonal regulation, and how changes in circadian timing impinge on endocrine signalling and downstream processes. We further summarize recent findings suggesting that hormonal signals may feed back on circadian regulation and how this crosstalk interferes with physiological and metabolic homeostasis.

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11

Dvornyk, Volodymyr. "Evolution of the Circadian Clock Mechanism in Prokaryotes." Israel Journal of Ecology and Evolution 52, no. 3-4 (April 12, 2006): 343–57. http://dx.doi.org/10.1560/ijee_52_3-4_343.

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The circadian system of prokaryotes is probably the oldest among the circadian systems of living organisms. The genes comprising the system are very different in their evolutionary histories. The reconstruction of macroevolution of the circadian genes in cyanobacteria suggests that there are probably at least two types of circadian systems, based either on the threekaigenes (kaiA, kaiB, andkaiC) or onkaiBandkaiC.When referred to the recently published results about a genomic timescale of prokaryote evolution, the origin ofkaiBandsasAcorresponds to the appearance of anoxygenic photosynthesis, while the origin of thekaiBCoperon corresponds to the time when oxygenic photosynthesis evolved.The results of the studies performed so far suggest that major steps in macroevolution of the circadian system in cyanobacteria have been related to global changes in the environment and to keystone advances in biological evolution. This macroevolution has involved selection, multiple lateral transfers, gene duplications, and fusions as its primary driving forces. The proposed scenario of the circadian system's macroevolution is far from complete and will be updated as new genomic and sequence data are accumulated.

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12

Isorna, Esther, Nuria de Pedro, Ana I. Valenciano, Ángel L. Alonso-Gómez, and María J. Delgado. "Interplay between the endocrine and circadian systems in fishes." Journal of Endocrinology 232, no. 3 (March 2017): R141—R159. http://dx.doi.org/10.1530/joe-16-0330.

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The circadian system is responsible for the temporal organisation of physiological functions which, in part, involves daily cycles of hormonal activity. In this review, we analyse the interplay between the circadian and endocrine systems in fishes. We first describe the current model of fish circadian system organisation and the basis of the molecular clockwork that enables different tissues to act as internal pacemakers. This system consists of a net of central and peripherally located oscillators and can be synchronised by the light–darkness and feeding–fasting cycles. We then focus on two central neuroendocrine transducers (melatonin and orexin) and three peripheral hormones (leptin, ghrelin and cortisol), which are involved in the synchronisation of the circadian system in mammals and/or energy status signalling. We review the role of each of these as overt rhythms (i.e. outputs of the circadian system) and, for the first time, as key internal temporal messengers that act as inputs for other endogenous oscillators. Based on acute changes in clock gene expression, we describe the currently accepted model of endogenous oscillator entrainment by the light–darkness cycle and propose a new model for non-photic (endocrine) entrainment, highlighting the importance of the bidirectional cross-talking between the endocrine and circadian systems in fishes. The flexibility of the fish circadian system combined with the absence of a master clock makes these vertebrates a very attractive model for studying communication among oscillators to drive functionally coordinated outputs.

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13

Zhang, Haoran, Zengxuan Zhou, and Jinhu Guo. "The Function, Regulation, and Mechanism of Protein Turnover in Circadian Systems in Neurospora and Other Species." International Journal of Molecular Sciences 25, no. 5 (February 22, 2024): 2574. http://dx.doi.org/10.3390/ijms25052574.

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Circadian clocks drive a large array of physiological and behavioral activities. At the molecular level, circadian clocks are composed of positive and negative elements that form core oscillators generating the basic circadian rhythms. Over the course of the circadian period, circadian negative proteins undergo progressive hyperphosphorylation and eventually degrade, and their stability is finely controlled by complex post-translational pathways, including protein modifications, genetic codon preference, protein–protein interactions, chaperon-dependent conformation maintenance, degradation, etc. The effects of phosphorylation on the stability of circadian clock proteins are crucial for precisely determining protein function and turnover, and it has been proposed that the phosphorylation of core circadian clock proteins is tightly correlated with the circadian period. Nonetheless, recent studies have challenged this view. In this review, we summarize the research progress regarding the function, regulation, and mechanism of protein stability in the circadian clock systems of multiple model organisms, with an emphasis on Neurospora crassa, in which circadian mechanisms have been extensively investigated. Elucidation of the highly complex and dynamic regulation of protein stability in circadian clock networks would greatly benefit the integrated understanding of the function, regulation, and mechanism of protein stability in a wide spectrum of other biological processes.

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14

Mendlewicz, Julien. "Disruption of the Circadian Timing Systems." CNS Drugs 23, Supplement 2 (September 2009): 15–26. http://dx.doi.org/10.2165/11318630-000000000-00000.

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15

Ukai, Hideki, and Hiroki R. Ueda. "Systems Biology of Mammalian Circadian Clocks." Annual Review of Physiology 72, no. 1 (March 17, 2010): 579–603. http://dx.doi.org/10.1146/annurev-physiol-073109-130051.

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16

Mavroudis, P. D., J. D. Scheff, S. E. Calvano, and I. P. Androulakis. "Systems Biology of Circadian-Immune Interactions." Journal of Innate Immunity 5, no. 2 (2013): 153–62. http://dx.doi.org/10.1159/000342427.

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17

Ueda, H. R. "Systems Biology of Mammalian Circadian Clocks." Cold Spring Harbor Symposia on Quantitative Biology 72, no. 1 (January 2007): 365–80. http://dx.doi.org/10.1101/sqb.2007.72.047.

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18

Dunlap, Jay C., Jennifer J. Loros, Yi Liu, and Susan K. Crosthwaite. "Eukaryotic circadian systems: cycles in common." Genes to Cells 4, no. 1 (January 1999): 01–10. http://dx.doi.org/10.1046/j.1365-2443.1999.00239.x.

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19

Schulz, P. "C.05.01 Neurobiology of circadian systems." European Neuropsychopharmacology 19 (September 2009): S708. http://dx.doi.org/10.1016/s0924-977x(09)71149-6.

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20

Ueda, Hiroki. "Systems biology of mammalian circadian clocks." Neuroscience Research 65 (January 2009): S22. http://dx.doi.org/10.1016/j.neures.2009.09.1614.

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21

Dunlap, Jay C. "Common threads in eukaryotic circadian systems." Current Opinion in Genetics & Development 8, no. 4 (August 1998): 400–406. http://dx.doi.org/10.1016/s0959-437x(98)80109-3.

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22

Argamaso, Sharleen M., Allan C. Froehlich, Maureen A. McCall, Eviatar Nevo, Ignacio Provencio, and Russell G. Foster. "Photopigments and circadian systems of vertebrates." Biophysical Chemistry 56, no. 1-2 (September 1995): 3–11. http://dx.doi.org/10.1016/0301-4622(95)00009-m.

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23

Weyers, Marc H. "Vertebrate circadian systems. Structure and physiology." Behavioural Processes 11, no. 3 (August 1985): 333–34. http://dx.doi.org/10.1016/0376-6357(85)90032-4.

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24

Fuhr, Luise, Mónica Abreu, Patrick Pett, and Angela Relógio. "Circadian systems biology: When time matters." Computational and Structural Biotechnology Journal 13 (2015): 417–26. http://dx.doi.org/10.1016/j.csbj.2015.07.001.

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25

Paatela, Ellen, Dane Munson, and Nobuaki Kikyo. "Circadian Regulation in Tissue Regeneration." International Journal of Molecular Sciences 20, no. 9 (May 8, 2019): 2263. http://dx.doi.org/10.3390/ijms20092263.

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Circadian rhythms regulate over 40% of protein-coding genes in at least one organ in the body through mechanisms tied to the central circadian clock and to cell-intrinsic auto-regulatory feedback loops. Distinct diurnal differences in regulation of regeneration have been found in several organs, including skin, intestinal, and hematopoietic systems. Each regenerating system contains a complex network of cell types with different circadian mechanisms contributing to regeneration. In this review, we elucidate circadian regeneration mechanisms in the three representative systems. We also suggest circadian regulation of global translational activity as an understudied global regulator of regenerative capacity. A more detailed understanding of the molecular mechanisms underlying circadian regulation of tissue regeneration would accelerate the development of new regenerative therapies.

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26

Rea, Mark S., Mariana G. Figueiro, Andrew Bierman, and John D. Bullough. "Circadian light." Journal of Circadian Rhythms 8 (February 13, 2010): 2. http://dx.doi.org/10.1186/1740-3391-8-2.

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27

Park, Chulwook, Jean Hwang, Jae Woong Ahn, and Yu Jin Park. "Perceiving “Complex Autonomous Systems” in Symmetry Dynamics: Elementary Coordination Embedding in Circadian Cycles." International Journal of Environmental Research and Public Health 20, no. 1 (December 22, 2022): 166. http://dx.doi.org/10.3390/ijerph20010166.

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This study explored the biological autonomy and control of function in circumstances that assessed the presumed relationship of an organism with an environmental cycle. An understanding of this behavior appeals to the organism–environment system rather than just the organism. Therefore, we sought to uncover the laws underlying end-directed capabilities by measuring biological characteristics (motor synchrony) in an environmental cycle (circadian temperature). We found that the typical elementary coordination (bimanual) stability measure varied significantly as a function of the day–night temperature cycle. While circadian effects under artificially manipulated temperatures were not straightforward during the day–night temperature cycle, the circadian effect divided by the ordinary circadian rhythm remained constant during the day–night cycle. Our observation of this direct, robust relationship between the biological characteristics (body temperature and motor synchrony) and environmental processes (circadian temperature cycle) could mirror the adaptation of our biological system to the environment.

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28

Kass, Leonard, and Robert B. Barlow. "A circadian clock in the Limulus brain transmits synchronous efferent signals to all eyes." Visual Neuroscience 9, no. 5 (November 1992): 493–504. http://dx.doi.org/10.1017/s0952523800011299.

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AbstractA circadian clock in the brain of the horseshoe crab, Limulus polyphemus, has an important role in the function of the peripheral visual system. At night, the clock transmits neural activity to the lateral, ventral, and median eyes via efferent optic nerve fibers. The activity occurs in synchronous bursts (maximum rate of 2 bursts/s) with individual efferent fibers contributing a single spike in each burst. The circadian efferent activity originates in the protocerebrum. Lateral connections synchronize the efferent activity recorded from the two halves of the protocerebrum, suggesting the existence of bilateral circadian oscillators. Circadian efferent activity survives excision of the brain and isolation of the protocerebrum. We conclude that circadian clock and its complex neural circuitry are fundamental components of the Limulus visual system.

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29

Rosenwasser, Alan M., and Norman T. Adler. "Structure and function in circadian timing systems: Evidence for multiple coupled circadian oscillators." Neuroscience & Biobehavioral Reviews 10, no. 4 (December 1986): 431–48. http://dx.doi.org/10.1016/0149-7634(86)90005-9.

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30

Lakin-Thomas, Patricia L. "New models for circadian systems in microorganisms." FEMS Microbiology Letters 259, no. 1 (June 2006): 1–6. http://dx.doi.org/10.1111/j.1574-6968.2006.00211.x.

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31

De Haro, Luciano, and Satchidananda Panda. "Systems Biology of Circadian Rhythms: An Outlook." Journal of Biological Rhythms 21, no. 6 (December 2006): 507–18. http://dx.doi.org/10.1177/0748730406294767.

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32

Schmal, Christoph, Erik D. Herzog, and Hanspeter Herzel. "Measuring Relative Coupling Strength in Circadian Systems." Journal of Biological Rhythms 33, no. 1 (December 8, 2017): 84–98. http://dx.doi.org/10.1177/0748730417740467.

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33

Cassone, Vincent M. "Effects of melatonin on vertebrate circadian systems." Trends in Neurosciences 13, no. 11 (November 1990): 457–64. http://dx.doi.org/10.1016/0166-2236(90)90099-v.

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Hu, Wenye, and Wendy Davis. "Toward a Connected System—Understanding the Contribution of Light from Different Sources on Occupants’ Circadian Rhythms." Applied Sciences 11, no. 21 (October 25, 2021): 9939. http://dx.doi.org/10.3390/app11219939.

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Light that enters humans’ eyes and impacts circadian rhythms may come from various sources, including the sun, electric lighting systems, and self-luminous displays. Occupants’ activities strongly impact the light entering their eyes, which is difficult to predict and not yet well understood. This study investigated the circadian contributions of light from different sources in real building environments to better understand the variables that influence the circadian health of occupants. Spectral irradiance distributions at a position equivalent to the front of an eye of a seated occupant in various interior office spaces were collected. Daylight and electric light were measured separately, and light emitted from displays was measured when a variety of different computer tasks was performed. Circadian stimulus (CS) and α-opic irradiance, defined by CIE DIS026/E:2018, were further calculated, and the circadian effects of light from different sources were compared. The results show that daylight has the greatest circadian effect, while electric light in spaces that were predominantly designed with conventional downward lighting has a very limited impact. The circadian effect of light from screens was considerably high. The outcomes suggest that, to optimise the circadian effects of light, connected lighting systems are needed to control light from different sources.

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De Nobrega, Aliza K., and Lisa C. Lyons. "Drosophila: An Emergent Model for Delineating Interactions between the Circadian Clock and Drugs of Abuse." Neural Plasticity 2017 (2017): 1–28. http://dx.doi.org/10.1155/2017/4723836.

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Endogenous circadian oscillators orchestrate rhythms at the cellular, physiological, and behavioral levels across species to coordinate activity, for example, sleep/wake cycles, metabolism, and learning and memory, with predictable environmental cycles. The 21st century has seen a dramatic rise in the incidence of circadian and sleep disorders with globalization, technological advances, and the use of personal electronics. The circadian clock modulates alcohol- and drug-induced behaviors with circadian misalignment contributing to increased substance use and abuse. Invertebrate models, such asDrosophila melanogaster, have proven invaluable for the identification of genetic and molecular mechanisms underlying highly conserved processes including the circadian clock, drug tolerance, and reward systems. In this review, we highlight the contributions ofDrosophilaas a model system for understanding the bidirectional interactions between the circadian system and the drugs of abuse, alcohol and cocaine, and illustrate the highly conserved nature of these interactions betweenDrosophilaand mammalian systems. Research inDrosophilaprovides mechanistic insights into the corresponding behaviors in higher organisms and can be used as a guide for targeted inquiries in mammals.

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Sati, Leyla. "Chronodisruption: effects on reproduction, transgenerational health of offspring and epigenome." Reproduction 160, no. 5 (November 2020): R79—R94. http://dx.doi.org/10.1530/rep-20-0298.

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The circadian system regulates the daily temporal organization in behavior and physiology, including neuroendocrine rhythms and reproduction. Modern life, however, increasingly impacts this complex biological system. Due to limitations of working with human subjects exposed to shift work schedules, most chronoregulation research has used rodent models. Recent publications in these model systems have emphasized the negative effects of circadian rhythm disruption on both female and male reproductive systems and fertility. Additionally, there is growing concern about the long-term effects of circadian rhythm disruptions during pregnancy on human offspring and their descendants as circadian regulation during pregnancy can also alter epigenetic programing in offspring. However, to truly know if such concerns apply to humans will require retrospective and prospective human studies. Therefore, this review will highlight the latest available evidence regarding potential effects of chronodisruption on both female and male reproductive systems. Additionally, it presents a comprehensive summary of transgenerational and epigenetic effects on adult offspring that result from maternal chronodisruption.

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Yari Kamrani, Yousef, Aida Shomali, Sasan Aliniaeifard, Oksana Lastochkina, Moein Moosavi-Nezhad, Nima Hajinajaf, and Urszula Talar. "Regulatory Role of Circadian Clocks on ABA Production and Signaling, Stomatal Responses, and Water-Use Efficiency under Water-Deficit Conditions." Cells 11, no. 7 (March 29, 2022): 1154. http://dx.doi.org/10.3390/cells11071154.

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Plants deploy molecular, physiological, and anatomical adaptations to cope with long-term water-deficit exposure, and some of these processes are controlled by circadian clocks. Circadian clocks are endogenous timekeepers that autonomously modulate biological systems over the course of the day–night cycle. Plants’ responses to water deficiency vary with the time of the day. Opening and closing of stomata, which control water loss from plants, have diurnal responses based on the humidity level in the rhizosphere and the air surrounding the leaves. Abscisic acid (ABA), the main phytohormone modulating the stomatal response to water availability, is regulated by circadian clocks. The molecular mechanism of the plant’s circadian clock for regulating stress responses is composed not only of transcriptional but also posttranscriptional regulatory networks. Despite the importance of regulatory impact of circadian clock systems on ABA production and signaling, which is reflected in stomatal responses and as a consequence influences the drought tolerance response of the plants, the interrelationship between circadian clock, ABA homeostasis, and signaling and water-deficit responses has to date not been clearly described. In this review, we hypothesized that the circadian clock through ABA directs plants to modulate their responses and feedback mechanisms to ensure survival and to enhance their fitness under drought conditions. Different regulatory pathways and challenges in circadian-based rhythms and the possible adaptive advantage through them are also discussed.

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Yang, Yunxia, and Jianfa Zhang. "Bile acid metabolism and circadian rhythms." American Journal of Physiology-Gastrointestinal and Liver Physiology 319, no. 5 (November 1, 2020): G549—G563. http://dx.doi.org/10.1152/ajpgi.00152.2020.

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Circadian rhythms are biological systems that synchronize cellular circadian oscillators and regulate nutrient absorption and utilization. Bile acids are important modulators that facilitate nutrient absorption and regulate energy metabolism. Bile acid metabolism and circadian rhythms are related to metabolic diseases, and their intersections have not been summarized clearly up to now. This review summarizes the molecular association between circadian rhythms and bile acid metabolism and points out future perspectives and potential therapeutic targets in metabolic diseases.

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Kiranmai, M. Sai, and M. Raajitha. "A COMPREHENSIVE REVIEW ON CHRONOTHERAPEUTICS." International Journal of Pharmaceutical Sciences and Medicine 8, no. 3 (March 30, 2023): 82–108. http://dx.doi.org/10.47760/ijpsm.2023.v08i03.007.

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Chronotherapy refers to the use of circadian, ultradian, infradian & seasonal, or other rhythmic cycles in the application of therapy. There are a number of conditions that show a circadian pattern and advantages could be taken by timing and adjusting the administration of drugs according to the circadian rhythm of the disease. Chronotherapy can be divided into three categories: time-controlled systems, in which the drug release is primarily controlled by the delivery system; stimuli-induced PDDS, in which release is controlled by the stimuli, such as the pH or intestinal enzymes; or externally regulated systems, in which release is programmed by external stimuli such as magnetism, ultrasound, electrical effect, and irradiation. The symptoms of some diseases, such as asthma, arthritis, depression, ulcer, allergic rhinitis, sleep disturbances, etc., are influenced by circadian rhythms. The biological clock of the human body is based on solar and lunar adaptations. The circadian rhythm is the primary rhythm that the biological clock adheres to. The functioning of the brain, behavior, and cognition can all be significantly impacted by circadian rhythm disruption. The use of chronotherapeutics can help with this. The recent interest that has occurred in the field of chronotherapeutics is to match the circadian rhythms of the disease for the successful treatment of the disease.

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40

Loros, J. J., J. C. Dunlap, L. F. Larrondo, M. Shi, W. J. Belden, V. D. Gooch, C. H. Chen, et al. "Circadian Output, Input, and Intracellular Oscillators: Insights into the Circadian Systems of Single Cells." Cold Spring Harbor Symposia on Quantitative Biology 72, no. 1 (January 2007): 201–14. http://dx.doi.org/10.1101/sqb.2007.72.067.

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41

Narumi, Ryohei, Yoshihiro Shimizu, Maki Ukai-Tadenuma, Koji L. Ode, Genki N. Kanda, Yuta Shinohara, Aya Sato, Katsuhiko Matsumoto, and Hiroki R. Ueda. "Mass spectrometry-based absolute quantification reveals rhythmic variation of mouse circadian clock proteins." Proceedings of the National Academy of Sciences 113, no. 24 (May 31, 2016): E3461—E3467. http://dx.doi.org/10.1073/pnas.1603799113.

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Absolute values of protein expression levels in cells are crucial information for understanding cellular biological systems. Precise quantification of proteins can be achieved by liquid chromatography (LC)–mass spectrometry (MS) analysis of enzymatic digests of proteins in the presence of isotope-labeled internal standards. Thus, development of a simple and easy way for the preparation of internal standards is advantageous for the analyses of multiple target proteins, which will allow systems-level studies. Here we describe a method, termed MS-based Quantification By isotope-labeled Cell-free products (MS-QBiC), which provides the simple and high-throughput preparation of internal standards by using a reconstituted cell-free protein synthesis system, and thereby facilitates both multiplexed and sensitive quantification of absolute amounts of target proteins. This method was applied to a systems-level dynamic analysis of mammalian circadian clock proteins, which consist of transcription factors and protein kinases that govern central and peripheral circadian clocks in mammals. Sixteen proteins from 20 selected circadian clock proteins were successfully quantified from mouse liver over a 24-h time series, and 14 proteins had circadian variations. Quantified values were applied to detect internal body time using a previously developed molecular timetable method. The analyses showed that single time-point data from wild-type mice can predict the endogenous state of the circadian clock, whereas data from clock mutant mice are not applicable because of the disappearance of circadian variation.

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42

Dalchau, Neil, and Alex A. R. Webb. "Ticking over: Circadian systems across the kingdoms of life." Biochemist 33, no. 1 (February 1, 2011): 12–15. http://dx.doi.org/10.1042/bio03301012.

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The ability to anticipate the day–night cycle and direct physiology accordingly has proven to be a general phenomenon across all kingdoms of life. Considerable fitness benefits are conferred by an internal 24hour clock, which is known as a circadian clock. Extensive multidisciplinary studies in a range of model organisms have elucidated many of the components involved in generating and sustaining daily rhythms. When comparing the circadian systems across the kingdoms, it is fascinating to observe the commonalities and differences in their molecular architecture, and the many adaptations which have evolved to deal with organismspecific requirements of biological timing.

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Kim, Eun Hye, Inseop Son, Seungwoo Baek, You Jin Nam, Sunhwa Hong, Yong Hyuk Cho, Sang Joon Son, Chang Hyung Hong, and Hyun Woong Roh. "A Path to Better Sleep and Circadian Health: Optimizing and Personalizing Indoor Lighting." Chronobiology in Medicine 6, no. 2 (June 30, 2024): 44–47. http://dx.doi.org/10.33069/cim.2024.0013.

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Circadian rhythms play a crucial role in the regulation of sleep, metabolism, and cognitive function. However, they are highly sensitive to disturbances caused by irregular indoor lighting, especially exposure to blue light at night. This review explored the impact of indoor lighting on circadian and sleep health by analyzing trends in light exposure, socioeconomic disparities, and the prioritization of economic efficiency over health in modern lighting design. Significant variations in individual circadian rhythms present a challenge in creating standardized lighting environments. To address this issue, a review suggested the development of personalized lighting systems that use advanced sensors to monitor and respond to the circadian phase of each individual. By dynamically adjusting light intensity, wavelength, and timing, these systems can better align with personal biological clocks, promote optimal sleep and overall health, and advance the concept of truly human-centric lighting environments.

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Helfrich-Förster, Charlotte, Michael N. Nitabach, and Todd C. Holmes. "Insect circadian clock outputs." Essays in Biochemistry 49 (June 30, 2011): 87–101. http://dx.doi.org/10.1042/bse0490087.

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Insects display an impressive variety of daily rhythms, which are most evident in their behaviour. Circadian timekeeping systems that generate these daily rhythms of physiology and behaviour all involve three interacting elements: the timekeeper itself (i.e. the clock), inputs to the clock through which it entrains and otherwise responds to environmental cues such as light and temperature, and outputs from the clock through which it imposes daily rhythms on various physiological and behavioural parameters. In insects, as in other animals, cellular clocks are embodied in clock neurons capable of sustained autonomous circadian rhythmicity, and those clock neurons are organized into clock circuits. Drosophila flies spend their entire lives in small areas near the ground, and use their circadian brain clock to regulate daily rhythms of rest and activity, so as to organize their behaviour appropriately to the daily rhythms of their local environment. Migratory locusts and butterflies, on the other hand, spend substantial portions of their lives high up in the air migrating long distances (sometimes thousands of miles) and use their circadian brain clocks to provide time-compensation to their sun-compass navigational systems. Interestingly, however, there appear to be substantial similarities in the cellular and network mechanisms that underlie circadian outputs in all insects.

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Merrow, Martha, and Mary Harrington. "A functional context for heterogeneity of the circadian clock in cells." PLOS Biology 18, no. 10 (October 14, 2020): e3000927. http://dx.doi.org/10.1371/journal.pbio.3000927.

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Characterization of circadian systems at the organism level—a top-down approach—has led to definition of unifying properties, a hallmark of the science of chronobiology. The next challenge is to use a bottom-up approach to show how the molecular workings of the cellular circadian clock work as building blocks of those properties. We review new studies, including a recently published PLOS Biology paper by Nikhil and colleagues, that show how programmed but also stochastic generation of variation in cellular circadian period explain important adaptive features of entrained circadian phase.

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Richards, Jacob, and Michelle L. Gumz. "Mechanism of the circadian clock in physiology." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 304, no. 12 (June 15, 2013): R1053—R1064. http://dx.doi.org/10.1152/ajpregu.00066.2013.

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It has been well established that the circadian clock plays a crucial role in the regulation of almost every physiological process. It also plays a critical role in pathophysiological states including those of obesity and diabetes. Recent evidence has highlighted the potential for targeting the circadian clock as a potential drug target. New studies have also demonstrated the existence of “clock-independent effects” of the circadian proteins, leading to exciting new avenues of research in the circadian clock field in physiology. The goal of this review is to provide an introduction to and overview of the circadian clock in physiology, including mechanisms, targets, and role in disease states. The role of the circadian clocks in the regulation of the cardiovascular system, renal function, metabolism, the endocrine system, immune, and reproductive systems will be discussed.

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Fleshner, Michelle, Victoria Booth, Daniel B. Forger, and Cecilia G. Diniz Behn. "Circadian regulation of sleep–wake behaviour in nocturnal rats requires multiple signals from suprachiasmatic nucleus." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, no. 1952 (October 13, 2011): 3855–83. http://dx.doi.org/10.1098/rsta.2011.0085.

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The dynamics of sleep and wake are strongly linked to the circadian clock. Many models have accurately predicted behaviour resulting from dynamic interactions between these two systems without specifying physiological substrates for these interactions. By contrast, recent experimental work has identified much of the relevant physiology for circadian and sleep–wake regulation, but interaction dynamics are difficult to study experimentally. To bridge these approaches, we developed a neuronal population model for the dynamic, bidirectional, neurotransmitter-mediated interactions of the sleep–wake and circadian regulatory systems in nocturnal rats. This model proposes that the central circadian pacemaker, located within the suprachiasmatic nucleus (SCN) of the hypothalamus, promotes sleep through single neurotransmitter-mediated signalling to sleep–wake regulatory populations. Feedback projections from these populations to the SCN alter SCN firing patterns and fine-tune this modulation. Although this model reproduced circadian variation in sleep–wake dynamics in nocturnal rats, it failed to describe the sleep–wake dynamics observed in SCN-lesioned rats. We thus propose two alternative, physiologically based models in which neurotransmitter- and neuropeptide-mediated signalling from the SCN to sleep–wake populations introduces mechanisms to account for the behaviour of both the intact and SCN-lesioned rat. These models generate testable predictions and offer a new framework for modelling sleep–wake and circadian interactions.

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Price-Lloyd, N., M. Elvin, and C. Heintzen. "Synchronizing the Neurospora crassa circadian clock with the rhythmic environment." Biochemical Society Transactions 33, no. 5 (October 26, 2005): 949–52. http://dx.doi.org/10.1042/bst0330949.

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The metronomic predictability of the environment has elicited strong selection pressures for the evolution of endogenous circadian clocks. Circadian clocks drive molecular and behavioural rhythms that approximate the 24 h periodicity of our environment. Found almost ubiquitously among phyla, circadian clocks allow preadaptation to rhythms concomitant with the natural cycles of the Earth. Cycles in light intensity and temperature for example act as important cues that couple circadian clocks to the environment via a process called entrainment. This review summarizes our current understanding of the general and molecular principles of entrainment in the model organism Neurospora crassa, a simple eukaryote that has one of the best-studied circadian systems and light-signalling pathways.

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Erzurumlu, Yalcin, Deniz Catakli, and Hatice Kubra Dogan. "Circadian Oscillation Pattern of Endoplasmic Reticulum Quality Control (ERQC) Components in Human Embryonic Kidney HEK293 Cells." Journal of Circadian Rhythms 21 (April 3, 2023): 1. http://dx.doi.org/10.5334/jcr.219.

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The circadian clock regulates the “push-pull” of the molecular signaling mechanisms that arrange the rhythmic organization of the physiology to maintain cellular homeostasis. In mammals, molecular clock genes tightly arrange cellular rhythmicity. It has been shown that this circadian clock optimizes various biological processes, including the cell cycle and autophagy. Hence, we explored the dynamic crosstalks between the circadian rhythm and endoplasmic reticulum (ER)-quality control (ERQC) mechanisms. ER-associated degradation (ERAD) is one of the most important parts of the ERQC system and is an elaborate surveillance system that eliminates misfolded proteins. It regulates the steady-state levels of several physiologically crucial proteins, such as 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and the metastasis suppressor KAI1/CD82. However, the circadian oscillation of ERQC members and their roles in cellular rhythmicity requires further investigation. In the present study, we provided a thorough investigation of the circadian rhythmicity of the fifteen crucial ERQC members, including gp78, Hrd1, p97/VCP, SVIP, Derlin1, Ufd1, Npl4, EDEM1, OS9, XTP3B, Sel1L, Ufd2, YOD1, VCIP135 and FAM8A1 in HEK293 cells. We found that mRNA and protein accumulation of the ubiquitin conjugation, binding and processing factors, retrotranslocation-dislocation, substrate recognition and targeting components of ERQC exhibit oscillation under the control of the circadian clock. Moreover, we found that Hrd1 and gp78 have a possible regulatory function on Bmal1 turnover. The findings of the current study indicated that the expression level of ERQC components is fine-tuned by the circadian clock and major ERAD E3 ligases, Hrd1 and gp78, may influence the regulation of circadian oscillation by modulation of Bmal1 stability.

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Batista, R. T. B., M. C. I. del Rosario, R. D. Santos, E. R. Mendoza, and D. B. Ramirez. "EUCLIS–An information system for circadian systems biology." IET Systems Biology 1, no. 5 (September 1, 2007): 266–73. http://dx.doi.org/10.1049/iet-syb:20060078.

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