Circadian clocks. Medical search

Circadian Clocks: Biological mechanism that controls CIRCADIAN RHYTHM. Circadian clocks exist in the simplest form in cyanobacteria and as more complex systems in fungi, plants, and animals. In humans the system includes photoresponsive RETINAL GANGLION CELLS and the SUPRACHIASMATIC NUCLEUS that acts as the central oscillator.CLOCK Proteins: Basic helix-loop-helix (bHLH) domain-containing proteins that contain intrinsic HISTONE ACETYLTRANSFERASE activity and play important roles in CIRCADIAN RHYTHM regulation. Clock proteins combine with Arntl proteins to form heterodimeric transcription factors that are specific for E-BOX ELEMENTS and stimulate the transcription of several E-box genes that are involved in cyclical regulation. This transcriptional activation also sets into motion a time-dependent feedback loop which in turn down-regulates the expression of clock proteins.Circadian Rhythm: The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs and stimuli, hormone secretion, sleeping, and feeding.Biological Clocks: The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.Period Circadian Proteins: Circadian rhythm signaling proteins that influence circadian clock by interacting with other circadian regulatory proteins and transporting them into the CELL NUCLEUS.ARNTL Transcription Factors: Basic helix-loop-helix (bHLH) domain-containing proteins that play important roles in CIRCADIAN RHYTHM regulation. They combine with CLOCK PROTEINS to form heterodimeric transcription factors that are specific for E-BOX ELEMENTS and stimulate the transcription of several E-box genes that are involved in cyclical regulation.Cryptochromes: Flavoproteins that function as circadian rhythm signaling proteins in ANIMALS and as blue-light photoreceptors in PLANTS. They are structurally-related to DNA PHOTOLYASES and it is believed that both classes of proteins may have originated from an earlier protein that played a role in protecting primitive organisms from the cyclical exposure to UV LIGHT.Photoperiod: The time period of daily exposure that an organism receives from daylight or artificial light. It is believed that photoperiodic responses may affect the control of energy balance and thermoregulation.Circadian Rhythm Signaling Peptides and Proteins: A broad category of proteins that regulate the CIRCADIAN RHYTHM of an organism. Included here are proteins that transmit intracellular and intercellular signals in a chronological manner along with proteins that sense light and time-dependent changes in the environment such as the PHOTOPERIOD.Suprachiasmatic Nucleus: An ovoid densely packed collection of small cells of the anterior hypothalamus lying close to the midline in a shallow impression of the OPTIC CHIASM.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Nuclear Receptor Subfamily 1, Group D, Member 1: A DNA-binding orphan nuclear receptor that negatively regulates expression of ARNTL TRANSCRIPTION FACTORS and plays a role as a regulatory component of the circadian clock system. The Nr1d1 nuclear receptor expression is cyclically-regulated by a feedback loop involving its positive regulation by CLOCK PROTEIN; BMAL1 PROTEIN heterodimers and its negative regulation by CRYPTOCHROME and PERIOD PROTEINS.Flavoproteins Darkness: The absence of light.Feedback, Physiological: A mechanism of communication with a physiological system for homeostasis, adaptation, etc. Physiological feedback is mediated through extensive feedback mechanisms that use physiological cues as feedback loop signals to control other systems.Chronobiology Disorders: Disruptions of the rhythmic cycle of bodily functions or activities.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Casein Kinase Iepsilon: A casein kinase I isoenzyme with specificity for proteins involved the regulation of the CIRCADIAN RHYTHM.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Photoreceptor Cells, Invertebrate: Specialized cells in the invertebrates that detect and transduce light. They are predominantly rhabdomeric with an array of photosensitive microvilli. Illumination depolarizes invertebrate photoreceptors by stimulating Na+ influx across the plasma membrane.Basic Helix-Loop-Helix Transcription Factors: A family of DNA-binding transcription factors that contain a basic HELIX-LOOP-HELIX MOTIF.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Synechococcus: A form-genus of spherical to rod-shaped CYANOBACTERIA in the order Chroococcales. They contain THYLAKOIDS and are found in a wide range of habitats.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Neurospora crassa: A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.Activity Cycles: Bouts of physical irritability or movement alternating with periods of quiescence. It includes biochemical activity and hormonal activity which may be cellular. These cycles are shorter than 24 hours and include sleep-wakefulness cycles and the periodic activation of the digestive system.Nuclear Proteins: Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.Light Signal Transduction: The conversion of absorbed light energy into molecular signals.Melatonin: A biogenic amine that is found in animals and plants. In mammals, melatonin is produced by the PINEAL GLAND. Its secretion increases in darkness and decreases during exposure to light. Melatonin is implicated in the regulation of SLEEP, mood, and REPRODUCTION. Melatonin is also an effective antioxidant.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.E-Box Elements: DNA locations with the consensus sequence CANNTG. ENHANCER ELEMENTS may contain multiple copies of this element. E-boxes play a regulatory role in the control of transcription. They bind with basic helix-loop-helix (bHLH) type TRANSCRIPTION FACTORS. Binding specificity is determined by the specific bHLH heterodimer or homodimer combination and by the specific nucleotides at the 3rd and 4th position of the E-box sequence.Pineal Gland: A light-sensitive neuroendocrine organ attached to the roof of the THIRD VENTRICLE of the brain. The pineal gland secretes MELATONIN, other BIOGENIC AMINES and NEUROPEPTIDES.Casein Kinase Idelta: A casein kinase I isoenzyme that plays a regulatory role in a variety of cellular functions including vesicular transport, CHROMOSOME SEGREGATION; CYTOKINESIS, developmental processes, and the CIRCADIAN RHYTHM.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Jet Lag Syndrome: A chronobiologic disorder resulting from rapid travel across a number of time zones, characterized by insomnia or hypersomnolence, fatigue, behavioral symptoms, headaches, and gastrointestinal disturbances. (From Cooper, Sleep, 1994, pp593-8)Drug Chronotherapy: The adaptation of drug administration to the known variations in biological RHYTHMICITY, such as CIRCADIAN RHYTHMS. The treatment is aimed at supporting normal rhythms, or modifying the timing of therapy to achieve maximal efficacy and minimal adverse effect.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Oscillometry: The measurement of frequency or oscillation changes.Cell Cycle Proteins: Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.Mammals: Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.Periodicity: The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).Neurospora: A genus of ascomycetous fungi, family Sordariaceae, order SORDARIALES, comprising bread molds. They are capable of converting tryptophan to nicotinic acid and are used extensively in genetic and enzyme research. (Dorland, 27th ed)Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.Flowers: The reproductive organs of plants.Drosophila: A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.Arylalkylamine N-Acetyltransferase: An acetyltransferase with specificity towards the amine group of aromatic alkylamines (arylalkylamines) such as SEROTONIN. This enzyme is also referred to as serotonin acetylase despite the fact that serotonin acetylation can also occur through the action of broad specificity acetyltransferases such as ARYLAMINE N-ACETYLTRANSFERASE.Hypocotyl: The region of the stem beneath the stalks of the seed leaves (cotyledons) and directly above the young root of the embryo plant. It grows rapidly in seedlings showing epigeal germination and lifts the cotyledons above the soil surface. In this region (the transition zone) the arrangement of vascular bundles in the root changes to that of the stem. (From Concise Dictionary of Biology, 1990)Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.Genes, Plant: The functional hereditary units of PLANTS.Diapause, Insect: Seasonal suspension of insect growth development. It can be either induced by environmental cues (e.g., PHOTOPERIOD) or as a facultative part of the life cycle in order to time development with seasonal changes.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Eye Proteins Phytochrome: A blue-green biliprotein widely distributed in the plant kingdom.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Luciferases: Enzymes that oxidize certain LUMINESCENT AGENTS to emit light (PHYSICAL LUMINESCENCE). The luciferases from different organisms have evolved differently so have different structures and substrates.Cyanobacteria: A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Photobiology: The branch of biology dealing with the effect of light on organisms.Animals, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.Phytochrome B: A plant photo regulatory protein that exists in two forms that are reversibly interconvertible by LIGHT. In response to light it moves to the CELL NUCLEUS and regulates transcription of target genes. Phytochrome B plays an important role in shade avoidance and mediates plant de-etiolation in red light.Time Factors: Elements of limited time intervals, contributing to particular results or situations.NIH 3T3 Cells: A continuous cell line of high contact-inhibition established from NIH Swiss mouse embryo cultures. The cells are useful for DNA transfection and transformation studies. (From ATCC [Internet]. Virginia: American Type Culture Collection; c2002 [cited 2002 Sept 26]. Available from http://www.atcc.org/)Mice, Inbred C57BLNuclear Receptor Subfamily 1, Group F, Member 1: A DNA-binding orphan nuclear receptor that positively regulates expression of ARNTL TRANSCRIPTION FACTORS and is a regulatory component of the circadian clock system. The protein also has a role in neuron cell survival and differentiation in that loss of function mutations of its gene result in the mouse phenotype referred to as the STAGGERER MOUSE.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Luminescence: Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.Chronobiology Phenomena: Biological systems as affected by time. Aging, biological rhythms, and cyclic phenomena are included. Statistical, computer-aided mathematical procedures are used to describe, in mathematical terminology, various biological functions over time.Casein Kinase I: A casein kinase that was originally described as a monomeric enzyme with a molecular weight of 30-40 kDa. Several ISOENZYMES of casein kinase I have been found which are encoded by separate genes. Many of the casein kinase I isoenzymes have been shown to play distinctive roles in intracellular SIGNAL TRANSDUCTION.Behavior, Animal: The observable response an animal makes to any situation.Rod Opsins: Photosensitive proteins expressed in the ROD PHOTORECEPTOR CELLS. They are the protein components of rod photoreceptor pigments such as RHODOPSIN.Sleep Disorders, Circadian Rhythm: Dyssomnias associated with disruption of the normal 24 hour sleep wake cycle secondary to travel (e.g., JET LAG SYNDROME), shift work, or other causes.RNA, Plant: Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.Chronotherapy: The adaptation of therapeutic approaches such as pharmacological (DRUG CHRONOTHERAPY), surgical, radiological, or physical to the known variations in biological RHYTHMICITY, such as CIRCADIAN RHYTHMS. The treatment is aimed at supporting normal rhythms, or modifying the timing of therapy to achieve maximal efficacy and minimal adverse effect.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Feedback: A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.Plants, Genetically Modified: PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Solar System: The group of celestial bodies, including the EARTH, orbiting around and gravitationally bound by the sun. It includes eight planets, one minor planet, and 34 natural satellites, more than 1,000 observed comets, and thousands of lesser bodies known as MINOR PLANETS (asteroids) and METEOROIDS. (From Academic American Encyclopedia, 1983)Mesocricetus: A genus of the family Muridae having three species. The present domesticated strains were developed from individuals brought from Syria. They are widely used in biomedical research.Insect Proteins: Proteins found in any species of insect.Receptors, G-Protein-Coupled: The largest family of cell surface receptors involved in SIGNAL TRANSDUCTION. They share a common structure and signal through HETEROTRIMERIC G-PROTEINS.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Luminescent Measurements: Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.Genes, Insect: The functional hereditary units of INSECTS.Moon: The natural satellite of the planet Earth. It includes the lunar cycles or phases, the lunar month, lunar landscapes, geography, and soil.Plant Physiological Phenomena: The physiological processes, properties, and states characteristic of plants.Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Fungal Proteins: Proteins found in any species of fungus.Fagaceae: A plant family of the order Fagales subclass Hamamelidae, class Magnoliopsida.Zebrafish: An exotic species of the family CYPRINIDAE, originally from Asia, that has been introduced in North America. They are used in embryological studies and to study the effects of certain chemicals on development.Heteroptera: A suborder of HEMIPTERA, called true bugs, characterized by the possession of two pairs of wings. It includes the medically important families CIMICIDAE and REDUVIIDAE. (From Dorland, 28th ed)Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Lighting: The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.Phytochrome A: The primary plant photoreceptor responsible for perceiving and mediating responses to far-red light. It is a PROTEIN-SERINE-THREONINE KINASE that is translocated to the CELL NUCLEUS in response to light signals.Homeostasis: The processes whereby the internal environment of an organism tends to remain balanced and stable.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Receptors, Vasoactive Intestinal Peptide, Type II: A pituitary adenylate cyclase-activating peptide receptor subtype found in LYMPHOCYTES. It binds both PACAP and VASOACTIVE INTESTINAL PEPTIDE and regulates immune responses.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Wakefulness: A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.Receptors, Melatonin: A family of G-protein-coupled receptors that are specific for and mediate the effects of MELATONIN. Activation of melatonin receptors has been associated with decreased intracellular CYCLIC AMP and increased hydrolysis of PHOSPHOINOSITIDES.Photoreceptor Cells: Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.F-Box Proteins: A family of proteins that share the F-BOX MOTIF and are involved in protein-protein interactions. They play an important role in process of protein ubiquition by associating with a variety of substrates and then associating into SCF UBIQUITIN LIGASE complexes. They are held in the ubiquitin-ligase complex via binding to SKP DOMAIN PROTEINS.Cyanothece: A form-genus of unicellular coccoid to rod-shaped CYANOBACTERIA, in the order Chroococcales. Three different clusters of strains from diverse habitats are included.

Circadian clock resetting in the mouse changes with age. (1/573)

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Chronopharmaceutical drug delivery systems: Hurdles, hype or hope? (2/573)

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Interplay between low-temperature pathways and light reduction. (3/573)

Low temperature is one of the major factors that adversely affect crop yields by causing restraints on plant growth and productivity. However, most temperate plants have the ability to acclimate to cooler temperatures. Cold acclimation is a process which increases the freezing tolerance of an organism after exposure to low, non-freezing temperatures. The main trigger is a decrease in temperature levels, but light reduction has also been shown to have an important impact on acquired tolerance. Since the lowest temperatures are commonly reached during the night hours in winter time and is an annually recurring event, a favorable trait for plants is the possibility of sensing an imminent cold period. Consequently, extensive crosstalk between light- and temperature signaling pathways has been demonstrated and in this review interesting interaction points that have been previously reported in the literature are highlighted. (+info)

Heritable circadian period length in a wild bird population. (4/573)

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Circadian rhythms in gene expression: Relationship to physiology, disease, drug disposition and drug action. (5/573)

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PERsuading nuclear receptors to dance the circadian rhythm. (6/573)

The recurring light/dark cycle that has a period length of about 24 hours has been internalized in various organisms in the form of a circadian clock. This clock allows a precise orchestration of biochemical and physiological processes in the body thus improving performance. Recently, we found that the clock component PERIOD2 (PER2) can coordinate transcriptional regulation of metabolic, physiological, or behavioral pathways by interacting with nuclear receptors. PER2 appears to act as co-regulator of nuclear receptors linking clock function and transcriptional regulation at the level of protein-protein interactions. Here, we provide additional evidence for modulation of nuclear receptor dependent transcription by PER2 underscoring the broad implication of our finding. Taken together, our findings provide a base for the understanding of various disorders including mood disorders that have their roots in a temporal deregulation of basic metabolic processes. (+info)

Circadian clocks in the ovary. (7/573)

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Similarities in the circadian clock and photoperiodism in plants. (8/573)

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Circadian clock

A circadian clock, or circadian oscillator, is a biochemical oscillator that cycles with a stable phase and is synchronized ... Circadian clocks are the central mechanisms that drive circadian rhythms. They consist of three major components: a central ... The autoregulatory feedback loops in clocks take about 24 hour to complete a cycle and constitute a circadian molecular clock. ... Some spiders exhibit unusually long or short circadian clocks. Some trashline orbweavers, for example, have 18.5-hour circadian ...

Circadian Clock Associated 1

"CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL Function Synergistically in the Circadian Clock of Arabidopsis" Plant ... Circadian Clock Associated 1 (CCA1) is a gene that is central to the circadian oscillator of angiosperms. It was first ... The evolution of circadian clocks in land plants is not understood, because circadian rhythms have received little attention in ... "Loss of the circadian clock-associated protein 1 in Arabidopsis results in altered clock-regulated gene expression." Proc Natl ...

Jet lag

Brown, S. A. & Azzi, A. (2013). "Peripheral circadian oscillators in mammals". Circadian clocks. Berlin: Springer. pp. 45-66. ... When travelling across a number of time zones, the body clock (circadian rhythm) will be out of synchronisation with the ... There are two separate processes related to biological timing: circadian oscillators and homeostasis. The circadian system is ... The symptoms are caused by a circadian rhythm that is out of sync with the day-night cycle of the destination, as well as the ...

Period (gene)

Thus, circadian control of clock controlled genes that function in cell growth control and DNA damage response may affect the ... A homolog of CLOCK plays the same role in the human clock, and CYC is replaced by BMAL1. CRY has two human homologs, CRY1 and ... The mammalian period 1 and period 2 genes play key roles in photoentrainment of the circadian clock to light pulses. This was ... Griffin EA, Staknis D, Weitz CJ (October 1999). "Light-independent role of CRY1 and CRY2 in the mammalian circadian clock". ...

Jeffrey L. Price

The molecular circadian clock of D. melanogaster can be described as a feedback loop of transcription and translation, in which ... These results demonstrated a role for BDBT in the circadian clock. When BDBT was overexpressed, Price found that the ... 2017.[1] Dunlap, JC (1999). "Molecular bases for circadian clocks". Cell. 96 (2): 271-290. doi:10.1016/S0092-8674(00)80566-8. ... reliable phase markers for the Drosophila circadian clock. Price and Seghal mapped the mutations to chromosome 2 and termed the ...

White Collar-1

... but both WC-1 and WC-2 are required for the circadian clock to run. Because the core of the clock is based on a rhythmic ... The White Collar Complex (WCC), the heterodimer of WC-1 and WC-2, acts as a positive element in the circadian clock. WCC serves ... Crosthwaite SK, Loros JJ, Dunlap JC (Jun 1995). "Light-induced resetting of a circadian clock is mediated by a rapid increase ... Cha J, Zhou M, Liu Y (2015). "Methods to study molecular mechanisms of the Neurospora circadian clock". Methods in Enzymology. ...

Jeffrey C. Hall

Despite these genes being identified as necessary genes to the circadian clock, there was a variety of levels of expressions in ... July 1999). "mCRY1 and mCRY2 Are Essential Components of the Negative Limb of the Circadian Clock Feedback Loop". Cell. 98: 193 ... Dunlap, JC (January 1999). "Molecular Bases for Circadian Clocks". Cell. 96: 271-290. doi:10.1016/S0092-8674(00)80566-8. PMID ... "Role of the CLOCK Protein in the Mammalian Circadian Mechanism". Science. 280 (5369): 1564-1569. doi:10.1126/science.280.5369. ...

White Collar-2

WC-1 and WC-2 are analogous to Bmal and Clock proteins in the Mouse and Drosophila circadian systems in their positive ... Since then, Neurospora has become a model organism for studying circadian clocks and rhythms. WC-1 was first discovered from a ... Collett, Michael A.; Dunlap, Jay C.; Loros, Jennifer J. (2017-04-14). "Circadian Clock-Specific Roles for the Light Response ... Both the Clock Box and PLRE are involved in achieving maximal light induction, and the Clock Box is essential for maintaining ...

Cryptochrome

CRY1 and CRY2 act as light-independent inhibitors of CLOCK-BMAL1 components of the circadian clock. In plants, blue-light ... Therefore, CRY is involved in light perception and is an input to the circadian clock, however it is not the only input for ... This light regulation of CRY protein levels suggests that CRY has a circadian role upstream of other clock genes and components ... Sancar A, Lindsey-Boltz LA, Kang TH, Reardon JT, Lee JH, Ozturk N (June 2010). "Circadian clock control of the cellular ...

Casein kinase 1 isoform epsilon

... role to mediate CLOCK phosphorylation and repress CLOCK-dependent transcription within the Drosophila circadian clock". ... This oscillator, or "circadian clock," is made up of a transcription-translation negative feedback loop (TTNFL) in which ... Harms E, Young MW, Saez L (2003). "CK1 and GSK3 in the Drosophila and mammalian circadian clock". Novartis Foundation Symposium ... Ko CH, Takahashi JS (Oct 2006). "Molecular components of the mammalian circadian clock". Human Molecular Genetics. 15 Spec No 2 ...

RAR-related orphan receptor alpha

The core mammalian circadian clock is a negative feedback loop which consists of Per1/Per2, Cry1/Cry2, Bmal1, and Clock. This ... Ko CH, Takahashi JS (October 2006). "Molecular components of the mammalian circadian clock". Human Molecular Genetics. 15 Spec ... Zhao X, Cho H, Yu RT, Atkins AR, Downes M, Evans RM (May 2014). "Nuclear receptors rock around the clock". EMBO Reports. 15 (5 ... PDP1 and VRI in Drosophila regulate circadian rhythm's by competing for the same binding site, the VP box, similarly to how ROR ...

Akhilesh Reddy

"Dr Akhilesh Reddy Bio at the Lister Institute". O'Neill, John S.; Reddy, Akhilesh B. (26 January 2011). "Circadian clocks in ... Reddy's research group discovered the existence of circadian clocks in human red blood cells (erythrocytes) in 2011. With ... Therefore, his group discovered circadian rhythms without the formation of new RNA in higher organisms for the first time. In ... "Circadian rhythms persist without transcription in a eukaryote". Nature. 469 (7331): 554-558. doi:10.1038/nature09654. PMC ...

Time-Place learning

The latter may be based on external time-cues (Zeitgebers), or internally generated circadian rhythms ("biological clock"). TPL ... "Circadian clocks and memory: Time-place learning". Frontiers in Molecular Neuroscience. 6: 1-10. doi:10.3389/fnmol.2013.00008. ... hourglass or circadian clock?". Journal of Biological Rhythms. 6: 353-365. doi:10.1177/074873049100600406. Wenger, D.; Biebach ... As with circadian rhythms of activity, the spatio-temporal pattern of room visits shifted gradually over several days following ...

Anatomical terms of location

Central and peripheral circadian clocks in mammals. Annu Rev Neurosci. 2012; 35:445-62. doi:10.1146/annurev-neuro-060909-153128 ... Other examples include Central and peripheral circadian clocks, and central versus peripheral vision. These two terms relate to ...

Common misunderstandings of genetics

"The circadian clock: from molecules to behaviour". Ann. Med. 27 (4): 481-90. doi:10.3109/07853899509002457. PMID 8519510. ... There is good evidence that some basic aspects of human behaviour, such as circadian rhythms are genetically-based, but it is ...

Peroxiredoxin

O'Neill JS, Reddy AB (January 2011). "Circadian clocks in human red blood cells". Nature. 469 (7331): 498-503. doi:10.1038/ ... Peroxiredoxins have been implicated in the 24-hour internal circadian clock of many organisms. Catalase Oxidative stress ... O'Neill JS, van Ooijen G, Dixon LE, Troein C, Corellou F, Bouget FY, Reddy AB, Millar AJ (January 2011). "Circadian rhythms ... Bass J, Takahashi JS (January 2011). "Circadian rhythms: Redox redux". Nature. 469 (7331): 476-8. doi:10.1038/469476a. PMC ...

Ying-Hui Fu

Modeling of a human circadian mutation yields insights into clock regulation by PER2. Cell. 2007 Jan 12:128(1):59-70. Kaasik K ... Fu's lab identified two rare variants in the circadian clock gene PERIOD3 (PER3-P415A/H417R) in individuals with familial ... Glucose sensor O-GlcNAcylation coordinates with phosphorylation to regulate circadian clock. Cell Metab. 2013 Feb 5; 17(2):291- ... Ko, Caroline H.; Takahashi, Joseph S. (2006-10-15). "Molecular components of the mammalian circadian clock". Human Molecular ...

John B. Hogenesch

Later work revealed that BMAL1 is the only clock gene without which the circadian clock fails to function in humans. BMAL1 ... The result has been the creation of pages about genes involved in the circadian clock such as ARNTL, as well as pages about ... Scientists Unwind a Circadian Clock Mystery, Genetic Engineering and Biotechnology News, April 16, 2014, retrieved April 23, ... October 2, 2009). "A Genome-wide RNAi Screen for Modifiers of the Circadian Clock in Human Cells". Cell. 139 (1): 199-210. doi: ...

Cyanobacterial clock proteins

"Structure and function from the circadian clock protein KaiA of Synechococcus elongatus: a potential clock input mechanism". ... the cyanobacterial clock proteins are the main circadian regulator in cyanobacteria. The cyanobacterial clock proteins comprise ... Garces RG, Wu N, Gillon W, Pai EF (April 2004). "Anabaena circadian clock proteins KaiA and KaiB reveal a potential common ... Hitomi K, Oyama T, Han S, Arvai AS, Getzoff ED (2005). "Tetrameric architecture of the circadian clock protein KaiB. A novel ...

MiR-132

... "microRNA modulation of circadian-clock period and entrainment". Neuron. 54 (5): 813-29. doi:10.1016/j.neuron.2007.05.017. PMC ... where miR-132 is thought be involved in resetting the circadian clock in response to light. Inflammatory mediators such as ...

Charles Czeisler

1990 - Human circadian clock is highly light sensitive. 1995 - Blind people can still retain sleep rhythms if their eyes remain ... CS1 maint: Uses authors parameter (link) Li MD, Li CM, Wang Z (Sep 2012). "The role of circadian clocks in metabolic disease". ... His team discovered that light transduced by non-visual input (melanopsin activation) could reset the circadian clock in ... 2013.[12] "Human Biological Clock Set Back an Hour." Human Biological Clock Set Back an Hour. N.p., n.d. Web. 24 Apr. 2013. ...

Shift work

"Interactions between metabolism and circadian clocks: reciprocal disturbances". Ann N Y Acad Sci. 1243: 30-46. doi:10.1111/j. ... The circadian phase is relatively fixed in humans; attempting to shift it so that an individual is alert during the circadian ... Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of ... This may be due to alterations in circadian rhythm: melatonin, a known tumor suppressor, is generally produced at night and ...

Timeless (gene)

As part of the circadian clock, timeless is essential for entrainment to light-dark (LD) cycles. The typical period length of ... The timeless gene is an essential component of the molecular circadian clock in Drosophila. It acts as part of an ... Zeng H, Qian Z, Myers MP, Rosbash M (Mar 1996). "A light-entrainment mechanism for the Drosophila circadian clock". Nature. 380 ... Young MW, Kay SA (Sep 2001). "Time zones: a comparative genetics of circadian clocks". Nature Reviews Genetics. 2 (9): 702-715 ...

Rev-ErbA alpha

Delezie J, Challet E (Dec 2011). "Interactions between metabolism and circadian clocks: reciprocal disturbances". Annals of the ... can de-stabilize Rev-erbα protein and affect its function in the circadian clock. This may partly explain lithium's therapeutic ... "The orphan receptor Rev-erbalpha gene is a target of the circadian clock pacemaker". Journal of Molecular Endocrinology. 33 (3 ... "Nuclear receptor Rev-erbalpha is a critical lithium-sensitive component of the circadian clock". Science. 311 (5763): 1002-5. ...

FBXL3

Siepka SM, Yoo SH, Park J, Lee C, Takahashi JS (2007). "Genetics and neurobiology of circadian clocks in mammals". Cold Spring ... Ko CH, Takahashi JS (October 2006). "Molecular components of the mammalian circadian clock". Human Molecular Genetics. 15 Spec ... Toh KL (August 2008). "Basic science review on circadian rhythm biology and circadian sleep disorders" (PDF). Annals of the ... "SCFFbxl3 controls the oscillation of the circadian clock by directing the degradation of cryptochrome proteins". Science. 316 ( ...

Bioluminescence

It has an inbuilt biological clock and, even when kept in total darkness, turns its light on and off in a circadian rhythm. ... Some forms of bioluminescence are brighter (or exist only) at night, following a circadian rhythm. Bioluminescence has several ...

Chronotherapeutic Drug Delivery Systems | OMICS International

Master circadian clock of the body, the suprachiasmatic nucleus regulates the endogenous circadian rhythms present inside the ... Circadian rhythm: Franz Harberg coined the term circadian which mean approximately one day. The series of events usually ... According to the circadian rhythms of the body drug is facilitated to completely release after a lag time especially for drugs ... Massin MM, Maeyns K, Withofs N, Ravet F, Gacrard P (2000) Circadian rhythm of heart rate and heart rate variability. Arch Dis ...

https://www.omicsonline.org/open-access/chronotherapeutic-drug-delivery-systems-2157-7609-1000194.php?aid=65452

RORA - NPSR1 - Asthma and Inflammatory Bowel Disease | asdresearchinitiative

In cell models, stimulation of NPSR1 activated a pathway including RORA and other circadian clock genes. ...

https://asdresearchinitiative.wordpress.com/2013/07/02/rora-npsr1-asthma-and-inflammatory-bowel-disease/

Role of Chronobiology as a Transdisciplinary Field of Research: Its Applications in Treating Mood Disorders - Balkan Medical...

Circadian clocks and mood-related behaviors. Handb Exp Pharmacol 2013:227-39. 14. Hampp G, Albrecht U. The circadian clock and ... The clock genes are involved in the generation of the circadian rhythms and the biological clock is synchronized to solar day ... Suprachiasmatic nucleus: the brains circadian clock. Recent prog Horm Res 1999;54:33-58.. 4. Moore RY. Circadian rhythms: ... Biological clock and circadian rhythms are useful if they can be adjusted to the local time, allowing ones alertness level to ...

http://balkanmedicaljournal.org/text.php?lang=en&id=1915

News Segments - Melatonin

Blue light helps set our body clocks - circadian rhythms, if youre feeling fancy. The natural human body clock is actually ... However, the team did find that the irregular sleepers had shifted their circadian rhythms - or biological clocks.. They worked ... Peoples biological clocks can become out of whack - which scientists call "circadian disruption" - if they work the night ... But as the clock creeps toward daybreak, REM sleep muscles in. Thats significant, because some research has suggested that non ...

https://melatonin.com/index.php/news-segments-2/

chronobiology

Host circadian clock as a control point in tumor progression. Filipski E, King VM, Li X, Granda TG, Mormont MC, Liu X, ... These daily, or circadian, cycles repeat themselves every 24 hours. Cells dont grow at a constant rate; rather there are ... Circadian timing in cancer treatment: the biological foundation for an integrative approach. Lis CG, Grutsch JF, Wood P, You M ... Our bodies go through a day as if multiple clocks were hardwired into our brains, organs, and very cells telling us what to do ...

http://www.denvernaturopathic.com/news/chronobiology.html

Awards - Canadian Society for Chronobiology

Poster Human: Grundy, Anne, Queens University, Kingston, ON "Shift work, circadian gene variants and risk of breast cancer" ... "Genes underlying social influence on Drosophila melanogaster clock" ... Anne-Monique Nuyt) for her presentation entitled: "Effects of neonatal transient high oxygen exposure on circadian regulation ... Poster Physiology: Fortier, Erin, Douglas Mental Health University Institute, McGill University, Montreal, QC "Circadian ...

http://www.chronobiocanada.com/awards/

Circadian clock - Wikipedia

Variation in circadian clocks[edit]. While a precise 24-hour circadian clock is found in many organisms, it is not universal. ... Plant clocks[edit]. The circadian clock in plants has completely different components to those in the animal, fungus or ... A circadian clock, or circadian oscillator, is a biochemical oscillator that cycles with a stable phase and is synchronized ... Mammalian clocks[edit]. Selective gene knockdown of known components of the human circadian clock demonstrates both active ...

https://en.wikipedia.org/wiki/Circadian_clock

Yes, Archaea also have circadian clocks! | ScienceBlogs

If you ever glanced at the circadian literature, you have probably encountered the statement that circadian rhythms are ... Clocks in Bacteria III: Evolution of Clocks in Cyanobacteria, Clocks in Bacteria IV: Clocks in other bacteria, Clocks in ... Circadian Clocks in Microorganisms, Clocks in Bacteria I: Synechococcus elongatus, Clocks in Bacteria II: Adaptive Function of ... Clocks in Bacteria IV: Clocks in other bacteria. Fourth in the five-part series on clocks in bacteria (from April 30, 2006): ...

https://scienceblogs.com/clock/2009/05/28/yes-archaea-also-have-circadia

Resonating circadian clocks enhance fitness in cyanobacteria | PNAS

However, FRP or clock-null mutations of circadian clock genes in Drosophila (per) or Neurospora (frq) do not obviously impair ... The Circadian Clock in Arabidopsis Roots Is a Simplified Slave Version of the Clock in Shoots ... The circadian clock controls the expression pattern of the circadian input photoreceptor, phytochrome B ... Quinone sensing by the circadian input kinase of the cyanobacterial circadian clock ...

https://www.pnas.org/content/95/15/8660

Circadian clocks: Providing Feedback | Science Signaling

Further clues into the regulation of circadian clocks are the subject of two reports. In plants and insects, cryptochromes ( ... In Drosophila, three of the critical clock genes, period (per), timeless (tim), and Drosophila Clock (dClk), are expressed ... role of CRY1 and light-independent role of CRY1 and light-iIndependent role of CRY1 and CRY2 in the mammalian circadian clock. ... show that CRY1 and CRY2 play a central role in the mammal clock, but in a light-independent fashion--they appear to regulate ...

http://stke.sciencemag.org/content/1999/5/tw7

Circadian clocks and pregnancy | Frontiers Research Topic

ClockΔ19) had prolonged and non-productive parturition, suggestive of a role for circadian clocks in the parturition event. ... A key study to draw attention to the potential role of the circadian clock and pregnancy was that of Miller et al (2004), who ... A growing body of research reveals circadian clock gene expression in the uterus of non-pregnant and pregnant mammals. ... 2010) examined expression of circadian clock genes in the mouse uterus in late pregnancy and found significant daily mRNA ...

https://www.frontiersin.org/research-topics/1010/circadian-clocks-and-pregnancy

Circadian Rhythms and Circadian Clock | NIOSH | CDC

Circadian Rhythms and Circadian Clock. Circadian Rhythms. *Are internally driven cycles that rise and fall during the 24-hour ... Circadian Clock. The circadian clock has an internally driven 24-hour rhythm that tends to run longer than 24 hours but resets ... The master circadian clock in the brain (see Figure 2) synchronizes and controls these cycles so they work together. ... The internal body clock sets the timing for many circadian rhythms, which regulate processes such as ...

https://www.cdc.gov/niosh/emres/longhourstraining/clock.html

Circadian clock not essential

... 25.09.2015. A circadian clock is not mandatory for living beings to adapt their activities to a ... The circadian clock sets the pace. Nevertheless, clockless fruit flies do show some behavioural differences. The clock seems to ... But this view of circadian clocks as central mechanisms that drive circadian rhythms was recently challenged. Scientists had ... And ideally its circadian clock will make the animal stop its activities before it is dark the next day. ...

http://www.innovations-report.com/html/reports/life-sciences/circadian-clock-not-essential.html

How Our Circadian Clocks Regulate Energy Metabolism

... body clocks) present in different parts of the body determine when and how much energy must be supplied by mitochondria (the ... Circadian Rhythm may Help Regulate Inflammatory Diseases. Controlling of the circadian rhythm or biological clock may help ... Relationship between circadian clock and energy production The scientists also showed that the mitochondrial network loses its ... Study Identifies How Internal Circadian Clocks Encode External Daily Rhythms of Excitability. A mechanism through which ...

https://www.medindia.net/news/how-our-circadian-clocks-regulate-energy-metabolism-177702-1.htm

How circadian clocks communicate with each other | EurekAlert! Science News

A new study now shows that a central clock governs the circadian rhythms in certain cases. ... Whether and how these clocks are connected with each other is still a largely open question. ... Multiple biological clocks control the daily rhythms of physiology and behavior in animals and humans. ... Rather, most organisms have a multitude of circadian clocks: a central clock in the brain and various peripheral clocks in the ...

https://www.eurekalert.org/pub_releases/2017-05/uow-hcc053017.php

Molecular and Genetic Analysis of Mammalian Circadian Clocks | HHMI.org

The molecular mechanisms of the clock are being studied at the biochemical and genomic levels. ... Joseph Takahashi is interested in understanding the genetic and molecular basis of circadian rhythms as well as other complex ... The Clock mutation lengthens circadian period by 4 hours in homozygous mutants, followed by a complete loss of circadian ... Molecular Mechanism of the Clock. The circadian clock in mammals is composed of an autoregulatory transcriptional network with ...

https://www.hhmi.org/research/molecular-and-genetic-analysis-mammalian-circadian-clocks

Light and the Human Circadian Clock | SpringerLink

Most clocks use the light-dark cycle as environmental signal (zeitgeber) for this active synchronisation. How we... ... The circadian clock can only reliably fulfil its function if it is stably entrained. ... Light and the Human Circadian Clock. In: Kramer A., Merrow M. (eds) Circadian Clocks. Handbook of Experimental Pharmacology, ... The circadian clock can only reliably fulfil its function if it is stably entrained. Most clocks use the light-dark cycle as ...

https://link.springer.com/chapter/10.1007%2F978-3-642-25950-0_13

Circadian clock cryptochrome proteins regulate autoimmunity | PNAS

Circadian clock cryptochrome proteins regulate autoimmunity. Qi Cao, Xuan Zhao, Jingwen Bai, Sigal Gery, Haibo Sun, De-Chen Lin ... C1qa, C1qb, C1qc, C6, Fcgr3, and Fcgr4 were down-regulated, and circadian clock genes Per2, Per3, Nr1d1, and Nr1d2 were up- ... 2012) Circadian expression of clock genes in mouse macrophages, dendritic cells, and B cells. Brain Behav Immun 26:407-413. ... indicating that the intrinsic circadian clock regulates inflammatory innate immune functions (11). The circadian oscillations ...

https://www.pnas.org/content/114/47/12548.long

Unnatural light-dark cycles expose duelling circadian clocks

One clock followed the artificially short 11-hr. day/11-hr. night schedule, while the other followed a longer cycle (>24 hrs ... In mammals, the endogenous daily pacemaker that regulates circadian rhythms like sleep and wakefulness is localized to a ... a regimen that effectively pushes the limits of the SCN s ability to set the clock to day length - researchers have discovered ... that underlies the workings of the circadian timing system. In humans, some of the symptoms arising from jet lag or rotating ...

https://www.innovations-report.com/html/reports/life-sciences/report-28753.html

'circadian clocks' Protocols and Video...

... circadian clocks include Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain ... Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters, In Vitro ... Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter, A ... Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures, ...

https://www.jove.com/keyword/circadian+clocks

Disruptions In Circadian Clock Have Health Consequences - Redorbit

... in the brain has a master circadian clock that manages cells, many of which have their own molecular clocks. ... According to the Cleveland Clinic, the circadian rhythm, otherwise known as the "internal body clock," manages the body´s 24- ... This study is the first to definitively prove that the body´s circadian biological clock controls insulin activity. ... The researchers used different approaches to disrupt the circadian clocks of individual mice. Measurements were taken at ...

https://www.redorbit.com/news/health/1112789435/fighting-your-biological-clock-can-have-health-consequences-022213

Dartmouth researchers find two circadian clocks in the same plant tissue

Dartmouth researchers have found evidence of two circadian clocks working within the same tissue of the plant Arabidopsis ... McClung and his students continued the study by examining how the circadian clocks were reset by different stimuli. For example ... Dartmouth researchers have found evidence of two circadian clocks working within the same tissue of the plant Arabidopsis ... Having two clocks with different sensitivities to light and to temperature is a better way to ensure that both signals of ...

http://www.dartmouth.edu/~news/releases/2003/may/050703.html

Circadian Clock Times Immune Response | Medpage Today

... to pathogenic invasion is controlled by circadian rhythms, researchers found. ... Circadian Clock Times Immune Response. The molecular response of an organism -- be it mouse or man -- to pathogenic invasion is ... To examine the influence of the circadian clock on immunity at the molecular level, Fikrigs group conducted a series of murine ... Source Reference: Silver A, et al "The circadian clock controls tool-like receptor 9-mediated innate and adaptive immunity" ...

https://www.medpagetoday.com/infectiousdisease/vaccines/31235

Characterization of Peripheral Circadian Clocks in Adipose Tissues | Diabetes

Circadian-controlled gene oscillations in adipose tissues.. The presence of active circadian clocks in BAT, iWAT, and eWAT was ... the expression of Clock did not follow a consistent circadian pattern in any of these tissues. Others have shown that Clock ... Characterization of Peripheral Circadian Clocks in Adipose Tissues. Sanjin Zvonic, Andrey A. Ptitsyn, Steven A. Conrad, L. ... Characterization of Peripheral Circadian Clocks in Adipose Tissues. Sanjin Zvonic, Andrey A. Ptitsyn, Steven A. Conrad, L. ...

http://diabetes.diabetesjournals.org/content/55/4/962

Kidneys' circadian clock regulates drug disposition, blood component levels

The kidneys contain a circadian clock that plays a key role in levels of certain blood components - such as lipids and amino ... Kidneys circadian clock regulates drug disposition, blood component levels. Published Friday 8 April 2016 Published Fri 8 Apr ... "Kidneys circadian clock regulates drug disposition, blood component levels." Medical News Today. MediLexicon, Intl., 8 Apr. ... The circadian clock is the bodys natural time-keeping mechanism, located in the suprachiasmatic nucleus of the brain. It ...

https://www.medicalnewstoday.com/articles/308808.php

In cell models, stimulation of NPSR1 activated a pathway including RORA and other circadian clock genes. (wordpress.com)

In vertebrates, the master circadian clock is contained within the suprachiasmatic nucleus (SCN), a bilateral nerve cluster of about 20,000 neurons. (wikipedia.org)
In mammals, the endogenous daily pacemaker that regulates circadian rhythms like sleep and wakefulness is localized to a defined site in the brain, the suprachiasmatic nucleus (SCN), which is composed of many neurons whose circadian activities are in synchrony with one another. (innovations-report.com)
Found in the brain´s hypothalamus, the suprachiasmatic nucleus (SCN) in the brain has a master circadian clock that manages cells, many of which have their own molecular clocks. (redorbit.com)
First described in the suprachiasmatic nucleus, circadian clocks have since been found in several peripheral tissues. (diabetesjournals.org)
20 days ex vivo, not just in the core circadian oscillator in the suprachiasmatic nucleus (SCN) but also in liver and muscle explants ( 8 ). (diabetesjournals.org)
The circadian clock is the body's natural time-keeping mechanism, located in the suprachiasmatic nucleus of the brain. (medicalnewstoday.com)
This gene is a member of the Period family of genes and is expressed in a circadian pattern in the suprachiasmatic nucleus, the primary circadian pacemaker in the mammalian brain. (nih.gov)
The suprachiasmatic nucleus (SCN) in the hypothalamus is the major clock in the body and receives its major input from light (via retinal neurons) and a minor input from nutrient intake. (wikipathways.org)
Data from studies conducted in rodent models show that circadian clock genes function both centrally in the suprachiasmatic nucleus and peripherally in key metabolic organs, including the liver, skeletal muscle, pancreatic islets, and adipose tissue ( 1 , 2 ) ( Fig. 1 ). (diabetesjournals.org)
Accumulated evidence indicates that the circadian clock exists and functions in many peripheral tissues, including immune tissues and cells, though the details of the nature of the immune clocks and their relationship to central clock in the suprachiasmatic nucleus (SCN) is not well understood. (dana.org)

The master circadian clock in the brain (see Figure 2) synchronizes and controls these cycles so they work together. (cdc.gov)

In 2017, the Nobel Prize in Physiology or Medicine was awarded to Jeffrey C. Hall , Michael Rosbash and Michael W. Young "for their discoveries of molecular mechanisms controlling the circadian rhythm" in fruit flies. (wikipedia.org)
The circadian clock has an internally driven 24-hour rhythm that tends to run longer than 24 hours but resets every day by the sun's light/dark cycle. (cdc.gov)
A new research has found that how exactly the 24 hour circadian rhythm regulates energy metabolism in the body. (medindia.net)
The scientists also showed that the mitochondrial network loses its rhythm if the circadian clock is impaired, which causes a decline in energy production in the cells. (medindia.net)
Similarly, pharmacologically or genetically impairing the Drp1 fission protein upsets the energy production rhythm, which in turn affects the rhythm of the circadian clock. (medindia.net)
Controlling of the circadian rhythm or biological clock may help reduce the severity of inflammatory diseases - peritoneal inflammation and fulminant hepatitis. (medindia.net)
Disruptions to circadian rhythm can alter the appetite and sleep patterns for days-and even contribute to conditions like heart disease, sleep disorders and cancers. (medindia.net)
In the presence of a normal day-and-night rhythm, as occurs in nature, a functioning peripheral clock alone is sufficient to sustain hatching in the early morning. (eurekalert.org)
The results: When both clocks run more slowly, the "hatching rhythm" increases from normally 24 hours to over 27. (eurekalert.org)
Researchers from Vanderbilt University recently found that disruptions in the body´s circadian rhythm are associated with increased risks of developing obesity, diabetes, and heart disease. (redorbit.com)
According to the Cleveland Clinic , the circadian rhythm, otherwise known as the "internal body clock," manages the body´s 24-hour cycle of biological processes and is found in both plants and animals. (redorbit.com)
The team of investigators utilized mice, as their circadian rhythm mirrors that of humans. (redorbit.com)
When given the protein that normally comes from the missing gene, the circadian rhythm was re-established thus lowering insulin resistance. (redorbit.com)
One such is circadian rhythm, which influences biological systems through neuroendocrine signaling according to the intensity of light. (medpagetoday.com)
Organisms throughout the phylogenetic tree display some form of circadian rhythm. (diabetesjournals.org)
A circadian rhythm is a roughly-24-hour cycle in the biochemical, physiological or behavioral processes of living entities, including plants, animals, fungi and cyanobacteria (see bacterial circadian rhythms). (medicalxpress.com)
The results from a series of studies have demonstrated the importance of normal circadian action for maintaining health in people and the disruption of circadian rhythm, which can have adverse effects on metabolic function. (diabetesjournals.org)
Disruption of central or peripheral circadian rhythms can cause an increase in food intake and obesity, which in turn can affect central and peripheral circadian rhythm activity and directly impair metabolic function. (diabetesjournals.org)
Inhibiting proteasome function leads to a circadian rhythm with a longer period. (wikipedia.org)

2010) examined expression of circadian clock genes in the mouse uterus in late pregnancy and found significant daily mRNA variations ex vivo for some but not for all clock genes. (frontiersin.org)
Following our recent discovery of circadian expression of circadian clock genes, per1-3 , in human and mPer1 and interlukine-2 ( mIL-2 ) in mouse peripheral blood mononuclear cells, we hypothesize that 1) the circadian clock genes will prove to be important to immune functioning in health and disease. (dana.org)

A circadian clock , or circadian oscillator , is a biochemical oscillator that cycles with a stable phase and is synchronized with solar time . (wikipedia.org)
P.E. (1999) Interlocked feedback loops within the Drosophila circadian oscillator. (sciencemag.org)
Furthermore, we have demonstrated that temporally restricted feeding causes a coordinated phase-shift in circadian expression of the major oscillator genes and their downstream targets in adipose tissues. (diabetesjournals.org)
The presence of circadian oscillator genes in fat has significant metabolic implications, and their characterization may have potential therapeutic relevance with respect to the pathogenesis and treatment of diseases such as obesity, type 2 diabetes, and the metabolic syndrome. (diabetesjournals.org)
By inhibiting photosynthesis, we demonstrate that endogenous oscillations in sugar levels provide metabolic feedback to the circadian oscillator through the morning-expressed gene PSEUDO-RESPONSE REGULATOR 7 (PRR7), and we identify that prr7 mutants are insensitive to the effects of sucrose on the circadian period. (nih.gov)
Circadian Clock Associated 1 (CCA1) is a gene that is central to the circadian oscillator of angiosperms. (wikipedia.org)
The Arabidopsis central oscillator contains several proteins that reciprocally repress genes encoding each other to achieve a negative feedback loop necessary to generate circadian rhythms controlling many clock outputs. (wikipedia.org)
The circadian oscillator in rice is similar to the Arabidopsis model, and researchers have used this model as a blueprint for understand the rice oscillator. (wikipedia.org)

Griffin Jr., E.A., Staknis, D., and Weitz, C.J. (1999) Light-independent role of CRY1 and light-independent role of CRY1 and light-iIndependent role of CRY1 and CRY2 in the mammalian circadian clock. (sciencemag.org)
Many questions regarding circadian clocks in the mammalian uterus remain unresolved. (frontiersin.org)
As evidence continues to accumulate for the expression of circadian clocks in the various layers of the mammalian uterus, numerous questions arise as to the identity of the cues for entrainment of these peripheral clocks, the synchronizing mechanisms across the uterus, as well as downstream clock gene targets. (frontiersin.org)
Brown SA, Zumbrunn G, Fleury-Olela F, Preitner N, Schibler U (2002) Rhythms of mammalian body temperature can sustain peripheral circadian clocks. (springer.com)
Buhr ED, Yoo SH, Takahashi JS (2010) Temperature as a universal resetting cue for mammalian circadian oscillators. (springer.com)
The researchers found that the resetting effect of DNA damage requires the period-4 clock protein, and that period-4 is the homolog, the Neurospora version, of the mammalian checkpoint kinase. (rxpgnews.com)
Recent evidence in mammalian cells shows that other cell cycle regulators physically interact with clock proteins. (rxpgnews.com)
Loss of at least one clock protein (mammalian period-2) is known to increase cancer susceptibility. (rxpgnews.com)
CK2alpha phosphorylates BMAL1 to regulate the mammalian clock. (wikipathways.org)

A mechanism through which circadian clocks in neurons encode external daily rhythms of excitability has been identified. (medindia.net)
Located in special nerve cells, the so-called circadian neurons, it interacts with the timeless protein causing it to be degraded. (innovations-report.com)
PTTH neurons (green) connect the circadian clock (magenta) of the brain with the peripheral clock in the prothoracic gland. (eurekalert.org)
In their search for the connecting pathway, the Würzburg scientists concentrated on specific neurons that could facilitate the contact between the central and the peripheral clock, the so-called PTTH neurons. (eurekalert.org)
In fact, the Würzburg scientists were able to show that the PTTH neurons establish a direct link between the brain-based clock of the fruit fly and its peripheral counterpart. (eurekalert.org)
They showed in experiments that the central clock neurons produce a special neuropeptide which transmits time information to the PTTH neurons. (eurekalert.org)
Now, for the first time, a team of neuroscientists at Beth Israel Deaconess Medical Center (BIDMC) has demonstrated circadian control of aggression in male mice and identified the specific neurons and circuitry regulating the daily pattern. (medindia.net)
Next, the scientists used genetics-based tools to manipulate neurons known to regulate the central circadian clock. (medindia.net)
Using optogenetics, a technique that uses light to activate or deactivate targeted brain cells - to map brain circuitry revealed two parallel pathways between the biological clock and a population of neurons in a sub-region of the hypothalamus (called the VMHvl) known to cause violent attacks when stimulated in male mice. (medindia.net)

A key study to draw attention to the potential role of the circadian clock and pregnancy was that of Miller et al (2004), who reported that pregnant mice lacking the functional Clock gene (ClockΔ19) had prolonged and non-productive parturition, suggestive of a role for circadian clocks in the parturition event. (frontiersin.org)

Circadian oscillators are ubiquitous in tissues of the body where they are synchronized by both endogenous and external signals to regulate transcriptional activity throughout the day in a tissue-specific manner. (wikipedia.org)
show that CRY1 and CRY2 play a central role in the mammal clock, but in a light-independent fashion--they appear to regulate transcriptional cycling of Per1 by contacting both the activator and its feedback inhibitors. (sciencemag.org)
After accumulating in the cytoplasm, PER and CRY proteins heterodimerize, translocate to the nucleus, and regulate the activity of CLOCK:BMAL1, completing a transcriptional/translational feedback loop ( 4 , 5 ). (diabetesjournals.org)
Now, researchers reveal how an internal clock within the kidneys helps regulate the levels of amino acids, lipids and other components in the blood, as well as eliminate drugs from the body. (medicalnewstoday.com)
In pancreatic islets, CLOCK and BMAL1 help regulate glucose-stimulated insulin secretion, and both ClockΔ19 mutant and pancreas-specific Bmal1 KO mice have impaired glucose tolerance because of β-cell dysfunction ( 14 ). (diabetesjournals.org)
Central and peripheral clocks interact with each other to regulate food intake and specific metabolic pathways in key organ systems ( 1 , 2 , 9 ). (diabetesjournals.org)

Evidence for a genetic basis of circadian rhythms in higher eukaryotes began with the discovery of the period ( per ) locus in Drosophila melanogaster from forward genetic screens completed by Ron Konopka and Seymour Benzer in 1971. (wikipedia.org)
Joseph Takahashi is interested in understanding the genetic and molecular basis of circadian rhythms as well as other complex behaviors. (hhmi.org)

The evolution of circadian clocks in land plants is not understood, because circadian rhythms have received little attention in plants other than angiosperms. (wikipedia.org)

have found that the molecular clock in Drosophila is composed of two interlocked negative feedback loops--the per-tim loop, which is activated by the dCLK and CYCLE proteins and repressed by PER-TIM, and the dClk loop, in which these proteins exert the opposite effect. (sciencemag.org)
The researchers in Chile had conducted a number of experiments in which they had artificially slowed down the circadian clocks of Drosophila in various combinations and observed the impact on the hatching behaviour. (eurekalert.org)
Bachleitner W, Kempinger L, Wulbeck C, Rieger D, Helfrich-Forster C (2007) Moonlight shifts the endogenous clock of Drosophila melanogaster. (springer.com)

Human casein kinase Idelta phosphorylation of human circadian clock proteins period 1 and 2. (wikipathways.org)

Circadian clocks are the central mechanisms that drive circadian rhythms . (wikipedia.org)
But this view of circadian clocks as central mechanisms that drive circadian rhythms was recently challenged. (innovations-report.com)
Whether fly, mouse or human, circadian clocks are the central mechanisms that drive circadian rhythms in all animals. (eurekalert.org)

Adipose tissue function in several disease states is associated with altered circadian rhythms. (diabetesjournals.org)
Hyperphosphorylation, due to the overexpression of CK2, will lead to altered circadian rhythms in the mutants where CCA1 showed shorter mRNA circadian oscillation than in wild-type plants. (wikipedia.org)

Taking melatonin a supplements can also shift the timing of the body's "clock. (cdc.gov)
Circadian rhythms boost the body's ability to fight intestinal bacterial infections. (medindia.net)
However, the notion of one, central clock regulating the timing of all the body's processes is not true. (eurekalert.org)
The body's circadian clock controls an early-evening agitation known as 'sundowning,' which is common in patients with Alzheimer's disease and dementia. (medindia.net)

By doing so, they found that the innate circadian clock regulates the kidney's ability to adapt to light and dark stages of the day that correlate with activity and rest. (medicalnewstoday.com)
The notion that the clock regulates DNA-damage input and that mutation can affect the clock as well as the cell cycle is novel. (rxpgnews.com)
Moreover, the clock regulates expression of the period-4 gene. (rxpgnews.com)
The findings demonstrate that Per3 has a major role in the APC clock and regulates adipogenesis in vivo. (nih.gov)
Title: The Circadian Clock Regulates Adipogenesis by a Per3 Crosstalk Pathway to Klf15. (nih.gov)

The circadian clock in mammals is composed of an autoregulatory transcriptional network with interlocked feedback loops (Figure 1). (hhmi.org)
Circadian clocks comprise transcription-translation feedback loops, which are entrained by environmental signals such as light and temperature to adjust the phase of rhythms to match the local environment. (nih.gov)

A growing body of research reveals circadian clock gene expression in the uterus of non-pregnant and pregnant mammals. (frontiersin.org)
Here, the adrenal cortex has a similar function as the prothoracic gland.Yet, instead of ecdysone it secretes glucocorticoids which are believed to play a central role in synchronizing the circadian clocks of mammals. (eurekalert.org)
The waxing and waning of this transcriptional feedback loop takes approximately 24 hours and represents the core mechanism of the circadian clock in mammals. (hhmi.org)

Adipose tissue is a source of tumor necrosis factor-α, interleukin-6, adiponectin, leptin, and plasminogen activator inhibitor-1 (PAI-1), whose circulating levels display a strong circadian pattern ( 11 - 13 ). (diabetesjournals.org)

Circadian (daily) rhythms are ubiquitous in eukaryotes and are also found in eubacteria among cyanobacteria ( 1 , 2 ). (pnas.org)

An appropriate way to determine the adaptive significance of circadian programs would be to examine the reproductive fitness of mutants whose circadian clockwork is altered. (pnas.org)

The CLOCK protein acts as a heterodimeric transcription factor with a partner known as BMAL1 (ARNTL). (hhmi.org)
Crystal structure of CLOCK:BMAL1. (hhmi.org)
Ribbon diagram of CLOCK:BMAL1 heterodimer. (hhmi.org)
CLOCK subunit is green, and BMAL1 is blue. (hhmi.org)
The PER and CRY proteins associate and translocate into the nucleus during the evening and physically interact with the CLOCK:BMAL1 complex to repress their own transcription. (hhmi.org)
CLOCK heterodimerizes with BMAL1 to drive the rhythmic expression of Per and Cry ( 2 , 3 ). (diabetesjournals.org)
In vitro studies of fibroblast cell lines further support these findings, where exposure to dexamethasone, high serum concentrations, or glucose induces the circadian expression of Clock , Per , Dbp , and Bmal1 ( 9 ). (diabetesjournals.org)
For their study, the researchers inhibited the expression of a gene in the kidneys called Bmal1, which plays a crucial role in the organs' circadian clock mechanism. (medicalnewstoday.com)
the CRY and PER proteins then inhibit transactivation by BMAL1:CLOCK/NPAS2. (wikipathways.org)
Transcription of the BMAL1 (ARNTL) gene is controlled by ROR-alpha and REV-ERBA (NR1D1), both of which are targets of BMAL1:CLOCK/NPAS2 in mice and both of which compete for the same element (RORE) in the BMAL1 promoter. (wikipathways.org)
BMAL1 can form heterodimers with either CLOCK or NPAS2, which act redundantly but show different tissue specificity. (wikipathways.org)
Within the nucleus the PER:CRY complexes bind BMAL1:CLOCK and BMAL1:NPAS2, inhibiting their transactivation activity and their phosphorylation. (wikipathways.org)
Gluconeogenesis is impaired in both ClockΔ19 mutant and Bmal1 knockout (KO) mice ( 10 ), and hepatic glucose export is also dysregulated in liver-specific Bmal1 KO mice ( 11 ). (diabetesjournals.org)
In skeletal muscle, CLOCK and BMAL1 are essential for the maintenance of normal mitochondrial biogenesis and respiratory function ( 13 ). (diabetesjournals.org)

Under constant light conditions, cca1 and lhy double loss of function mutants fail to maintain rhythms in clock controlled RNAs. (wikipedia.org)

This group discovered circadian rhythms in redox proteins (peroxiredoxins) in cells that lacked a nucleus - human red blood cells. (wikipedia.org)

Circadian rhythms are 24-hour oscillations in behavior, physiology, and biochemistry that are generated by a cell-autonomous clock system found in all classes of living organisms. (hhmi.org)
The circadian clock is cell-autonomous and some, but not all cells of the body exhibit circadian rhythms in metabolism, cell division, and gene transcription. (wikipathways.org)
and 2) the clock regulatory mechanism in immune cells is regulated in part by SCN central clock through circadian signaling molecules, but functions as cell autonomous in certain extent. (dana.org)

Scientists have now investigated exactly how the mitochondrial network interacts with our internal biological clock by using a combination of in vitro models and clock-deficient mice or mice with impaired mitochondrial fission. (medindia.net)
Using high-efficiency N -ethyl- N -nitrosourea mutagenesis, we isolated the first single-gene mutation that affects circadian rhythms in mice. (hhmi.org)
Using a combined approach of positional cloning and transgenic (functional) rescue of the Clock mutation in mice, we found that the Clock gene encodes a novel member of the basic helix-loop-helix (bHLH)-PAS family of transcription factors. (hhmi.org)
The researchers used different approaches to disrupt the circadian clocks of individual mice. (redorbit.com)
In another experiment, they used genetically modified mice that lacked the gene needed for proper biological clock function. (redorbit.com)
Note that this study demonstrates that the circadian molecular clock controls the expression and function of toll-like receptor 9 (TLR9), which in turn modulates the response to vaccination and sepsis models in mice. (medpagetoday.com)
The effect of different photoperiods in circadian rhythms of per3 knockout mice. (nih.gov)
Importantly, deletion of Reverba inverted circadian liver GC sensitivity and protected mice from hepatosteatosis induced by chronic GC administration. (jci.org)
Then, these profiles will be used to compare with the ones derived from one strain of tissue-specific mutant mice, which is generated from bone marrow transplantation and carries with normal immune clock but mutated SCN clock ( SCN-mPer1 -/- /mPer2 -/- ). (dana.org)

The identification of circadian clocks in endocrine tissues has added considerable depth and complexity to our understanding of their physiology. (frontiersin.org)

Their work, reported June 29 in Science Express, the advance electronic publication of Science, implies a protective dimension for the biological clock in addition to its pacemaker functions that play such a sweeping role in the rhythms and activities of life. (rxpgnews.com)

These results are consistent with the idea that ovarian steroid levels during the estrous cycle have a modulating influence of clock gene expression in the uterus. (frontiersin.org)
To examine the influence of the circadian clock on immunity at the molecular level, Fikrig's group conducted a series of murine experiments in which they demonstrated the variation of TLR9 expression and daily peaks in clock gene expression. (medpagetoday.com)
These results correlated with respective gene expression in liver and the serum markers of circadian function. (diabetesjournals.org)

These developments will contribute greatly to new diagnostic and therapeutic approaches in obstetrics and gynecology, as well as improving our basic understanding of circadian mechanisms in all endocrine systems. (frontiersin.org)
Other mechanisms are capable of compensating for the loss of the molecular clock as researchers from the University of Würzburg have now shown. (innovations-report.com)
She is also the spokeswoman of the Collaborative Research Center "Insect timing: mechanisms, plasticity and interactions" which was set up in early 2013 to study among other questions how circadian clocks work in animals. (innovations-report.com)
The molecular mechanisms of the clock are being studied at the biochemical and genomic levels. (hhmi.org)
Because cytokines that are produced by lymphocytes and macrophages are potent mediators of immune responses and the level of individual cytokines can determine immune effector mechanisms, understanding immune-circadian control of specific immune mechanisms, perhaps especially those of the innate immune system, may have important clinical applications, such as the optimization of treatment for patients with acute infection and autoimmune and hematological diseases. (dana.org)

In most living things, internally synchronized circadian clocks make it possible for the organism to anticipate daily environmental changes corresponding with the day-night cycle and adjust its biology and behavior accordingly. (wikipedia.org)
But whether the circadian clock regulated aggressive behavior was unknown. (medindia.net)

Rhythmic control of mRNA stability modulates circadian amplitude of mouse Period3 mRNA. (nih.gov)
Post-transcriptional mRNA stability modulation controls the phase for circadian mPer3 expression. (nih.gov)

Rather, most organisms have a multitude of circadian clocks: a central clock in the brain and various peripheral clocks in the organs and systems. (eurekalert.org)

However, chronic glucocorticoid (GC) treatment leads to disordered energy metabolism, including increased weight gain, adiposity, and hepatosteatosis - all programs modulated by the circadian clock. (jci.org)
Our results reveal a mechanism by which the circadian clock acts through REVERBa in liver on elements bound by HNF4A/HNF6 to direct GR action on energy metabolism. (jci.org)

2009). Progesterone, but not estradiol, served to synchronize the circadian rhythms in these cells. (frontiersin.org)
Yet, it is still largely unknown how these clocks communicate with each other, how they synchronize and whether the central clock sets the time for all other units. (eurekalert.org)

Protein Drp1, synchronized by an internal biological clock determines the energy needed to be supplied. (medindia.net)
Their results show that the mitochondrial fission-fusion cycle is controlled by the fission protein Drp1, which is in turn synchronized by an internal biological clock. (medindia.net)
Past studies have looked at the relationship between the body´s metabolism and the operation of the body´s biological clock. (redorbit.com)
This study is the first to definitively prove that the body´s circadian biological clock controls insulin activity. (redorbit.com)

Two papers appearing April 18 in the journal Cell Metabolism confirm that the circadian clock is an important factor in how the body responds to physical exertion. (medicalxpress.com)
Circadian clocks provide a competitive advantage in an environment that is heavily influenced by the rotation of the Earth, by driving daily rhythms in behaviour, physiology and metabolism in bacteria, fungi, plants and animals. (nih.gov)

We tested the adaptive significance of circadian programming by measuring the relative fitness under competition between various strains of cyanobacteria expressing different circadian periods. (pnas.org)

Temporal segregation of GC action was underpinned by a physical interaction of GR with the circadian transcription factor REVERBa and co-binding with liver-specific hepatocyte nuclear transcription factors (HNFs) on chromatin. (jci.org)

Note that circadian rhythms are autonomous, 24-hour oscillations in biologic processes controlled by environmental cues, most notably the daily changes in light intensity. (medpagetoday.com)

So it appears that most Eukaryotes have clocks and at least some bacteria have them as well. (scienceblogs.com)

In humans and most other living things, circadian rhythms primarily respond to sunlight and darkness. (medicalnewstoday.com)

1. To investigate if there is autonomous immune clock by using in vivo approach. (dana.org)

This gene is upregulated by Clock/Arntl heterodimers but then represses this upregulation in a feedback loop using Per/Cry heterodimers to interact with Clock/Arntl. (nih.gov)

The clock normally modulates expression of this gene that encodes an important cell cycle regulator, and that cell cycle regulator in turn affects not only the cell cycle but also the clock. (rxpgnews.com)

The understanding of the way bacterial clocks work (more like a relay or a switch than a clock) made us rethink the clock metaphor we have been using for almost a century. (scienceblogs.com)

It controls our circadian rhythms - changes to physical, mental and behavioral processes that closely follow a 24-hour cycle. (medicalnewstoday.com)

Circadian clock resetting in the mouse changes with age. (1/573)

Chronopharmaceutical drug delivery systems: Hurdles, hype or hope? (2/573)

Interplay between low-temperature pathways and light reduction. (3/573)

Heritable circadian period length in a wild bird population. (4/573)

Circadian rhythms in gene expression: Relationship to physiology, disease, drug disposition and drug action. (5/573)

PERsuading nuclear receptors to dance the circadian rhythm. (6/573)

Circadian clocks in the ovary. (7/573)

Similarities in the circadian clock and photoperiodism in plants. (8/573)

Circadian clock

Circadian Clock Associated 1

Jet lag

Period (gene)

Jeffrey L. Price

White Collar-1

Jeffrey C. Hall

White Collar-2

Cryptochrome

Casein kinase 1 isoform epsilon

RAR-related orphan receptor alpha

Akhilesh Reddy

Time-Place learning

Anatomical terms of location

Common misunderstandings of genetics

Peroxiredoxin

Ying-Hui Fu

John B. Hogenesch

Cyanobacterial clock proteins

MiR-132

Charles Czeisler

Shift work

Timeless (gene)

Rev-ErbA alpha

FBXL3

Bioluminescence

Chronotherapeutic Drug Delivery Systems | OMICS International

RORA - NPSR1 - Asthma and Inflammatory Bowel Disease | asdresearchinitiative

Role of Chronobiology as a Transdisciplinary Field of Research: Its Applications in Treating Mood Disorders - Balkan Medical...

News Segments - Melatonin

chronobiology

Awards - Canadian Society for Chronobiology

Circadian clock - Wikipedia

Yes, Archaea also have circadian clocks! | ScienceBlogs

Resonating circadian clocks enhance fitness in cyanobacteria | PNAS

Circadian clocks: Providing Feedback | Science Signaling

Circadian clocks and pregnancy | Frontiers Research Topic

Circadian Rhythms and Circadian Clock | NIOSH | CDC

Circadian clock not essential

How Our Circadian Clocks Regulate Energy Metabolism

How circadian clocks communicate with each other | EurekAlert! Science News

Molecular and Genetic Analysis of Mammalian Circadian Clocks | HHMI.org

Light and the Human Circadian Clock | SpringerLink

Circadian clock cryptochrome proteins regulate autoimmunity | PNAS

Unnatural light-dark cycles expose duelling circadian clocks

'circadian clocks' Protocols and Video...

Disruptions In Circadian Clock Have Health Consequences - Redorbit

Dartmouth researchers find two circadian clocks in the same plant tissue

Circadian Clock Times Immune Response | Medpage Today

Characterization of Peripheral Circadian Clocks in Adipose Tissues | Diabetes

Kidneys' circadian clock regulates drug disposition, blood component levels

Genes1

Suprachiasmatic nucleus10

Master circadian clock1

Rhythm19

Expression of circadian clock genes2

Oscillator8

Mammalian9

Neurons9

Role of the circadian clock1

Regulate6

Basis of circadian rhythms2

Evolution of circadian clocks1

Drosophila3

Human Circadian Clock1

Drive circadian rhythms3

Altered circadian rhythms2

Body's4

Regulates5

Feedback loops2

Mammals3

Strong circadian1