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.FlavoproteinsDarkness: 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 ProteinsPhytochrome: 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)

 (+info)

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

 (+info)

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)

 (+info)

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

 (+info)

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)

 (+info)

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

 (+info)

*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 ...
The identification of circadian clocks in endocrine tissues has added considerable depth and complexity to our understanding of their physiology. A growing body of research reveals circadian clock gene expression in the uterus of non-pregnant and pregnant mammals. 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. Nakamura et al. (2010) showed changes in Per2::LUC rhythmic phase and amplitude in uterine explants treated with estrogen and progesterone. 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. Ratajczak et al. (2010) examined expression of circadian clock genes in the mouse uterus in late pregnancy and
The circadian clock is an endogenous time-keeping system that coordinates the physiology and behavior of a living organism to its environment [1]. In plants, the clock modulates rhythmic leaf movement, elongation rate of hypocotyls, roots, and stems, stomata aperture, stem circumnutation, and flower opening [1, 2].. Three major interlocked feedback loops constitute the plant circadian clock: the central loop, the morning loop, and the evening loop [3-5]. The central loop is mediated by the reciprocal repression between the morning-phased MYB transcription factors, CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY), and the evening-phased pseudo-response regulator TIMING OF CAB EXPRESSION 1 (TOC1) [6, 7]. In the morning loop, CCA1 and LHY promote the transcription of PSEUDO-RESPONSE REGULATOR 9 (PRR9) and PRR7 genes [8, 9]. Closing the loop, the PRR members inhibit the transcription of CCA1 and LHY genes by sequentially binding to the gene promoters from early morning (PRR9) ...
Circadian clocks are molecular oscillators with ~24-hour periods that drive daily biological rhythms. Such clocks are found in all of the major branches of life, and they likely represent ancient timekeeping systems important for predicting daily environmental cycles on our rotating planet. In mammals, circadian clocks are present in most if not all cells. These distributed clocks control a myriad of processes, in aggregate creating coherent 24-hour programs of physiology and behavior.. A picture of how circadian clocks are built has emerged in the last two decades. The core mechanism is a transcriptional feedback loop, wherein the protein products of several clock genes build the molecular machinery to inhibit the transcription factor responsible for their own production. The molecular components of circadian clocks are conserved from insects to humans.. The Weitz lab uses molecular biology, biochemistry, genetics, and structural biology to investigate the mammalian circadian clock. The focus ...
Marked circadian rhythms in myocardial metabolism are mediated by as yet unidentified mechanism(s). Virtually every mammalian cell possesses an intrinsic circadian clock, a transcriptionally-based molecular mechanism capable of regulating multiple cellular functions. Recent studies suggest that the transcriptional co-activator, PGC1α, is an integral component of the mammalian circadian clock, which links this molecular mechanism to oxidative metabolism. To test the hypothesis that the circadian clock directly influences myocardial metabolism, a cardiomyocyte-specific circadian clock mutant (CCM) mouse was generated. Wild-type (WT) and CCM hearts were isolated and perfused in the working mode, for simultaneous assessment of myocardial contractile function and metabolism. Compared to WT, CCM hearts exhibited decreased cardiac efficiency independent of the time of day (13% lower; p,0.05), with greatest differences observed during the middle of the dark (awake) phase (29% lower; p,0.01). ...
Circadian rhythms control processes ranging from human sleep-wake cycles to cyanobacterial cell division. This is made possible by the circadian clock, an internal biochemical oscillator. The circadian clock allows organisms to anticipate daily changes in the environment such as the onset of dawn and dusk, providing them with an adaptive advantage (1). Physiological processes regulated by the clock in higher plants include photoperiodic induction of flowering (2) and rhythmic hypocotyl elongation, cotyledon movement, and stomatal opening (3). A small number of genes regulated by the clock have been found in an essentially serendipitous fashion (4, 5). However, a global examination of genes controlled by the clock in plants, or in any eukaryote, has been lacking.. The circadian clock regulates hundreds of genes. We have used highly reproducible oligonucleotide-based arrays (6) to determine steady-state mRNA levels inArabidopsis at 4-hour intervals during the subjective day and night. We examined ...
The circadian clock is an endogenous timekeeper that allows organisms to anticipate and adapt to the daily variations of their environment. The plant clock is an intricate network of interlocked feedback loops, in which transcription factors regulate each other to generate oscillations with expression peaks at specific times of the day. Over the last decade, mathematical modeling approaches have been used to understand the inner workings of the clock in the model plant Arabidopsis thaliana. Those efforts have produced a number of models of ever increasing complexity. Here, we present an alternative model that combines a low number of equations and parameters, similar to the very earliest models, with the complex network structure found in more recent ones. This simple model describes the temporal evolution of the abundance of eight clock genes and captures key features of the clock on a qualitative level, namely the entrained and free-running behaviors of the wild type clock, as well as the defects
Disruption of circadian homeostasis is frequently observed in tumour cells. In a comprehensive study of circadian clock genes in 21 cancer types that takes into account genomic, transcriptomic and phenotypic (clinical prognosis) data, we demonstrated that clock genes were substantially altered by somatically acquired deletions and amplifications. Recurrent deletions or amplifications that were accompanied by altered transcript expression in tumours could represent novel loss- or gain-of-function phenotypes. To exploit these circadian targets in a clinical setting, we analysed survival outcomes using the ClockLoss and ClockGain and confirmed the utility of both gene sets as prognostic tools in 2914 and 2784 patients involving seven diverse cancer cohorts.. Depending on cellular context, the circadian clock can exert both tumour-promoting or tumour-inhibiting properties. We observed that core clock genes, PERs, CRY2, CLOCK, NR1D2, RORA and RORB exhibited global patterns of somatic loss and ...
Video articles in JoVE about circadian clocks include Single-cell Resolution Fluorescence Live Imaging of Drosophila Circadian Clocks in Larval Brain Culture, Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures, Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters, In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells, Assaying Locomotor Activity to Study Circadian Rhythms and Sleep Parameters in Drosophila, Analysis of Circadian Photoresponses in Drosophila Using Locomotor Activity, Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter, A Computational Method to Quantify Fly Circadian Activity, Desensitization and Recovery of Crayfish Photoreceptors Upon Delivery of a Light Stimulus, Flexible Measurement of Bioluminescent Reporters Using an Automated Longitudinal
article{3062551, abstract = {Previously, we identified HISTONE MONOUBIQUITINATION1 (HUB1) as an unconventional ubiquitin E3 ligase that is not involved in protein degradation but in the histone H2B modification that is implicated in transcriptional activation in plants. HUB1-mediated regulation of gene expression played a role in periodic and inducible processes such as the cell cycle, dormancy, flowering time and defense responses. Here, we determined the effects of the hub1-1 mutation on expression of a set of diurnally induced circadian clock genes identified from a comparative microarray analysis between the hub1-1 mutant and an HUB1 over-expression line. The hub1-1 mutation reduced the amplitudes of a number of induced clock gene expression peaks, as well as the HUB1-mediated histone H2BUb and H3K4Me3 marks associated with the coding regions, suggesting a role for HUB1 in facilitating transcriptional elongation in plants. Furthermore, double mutants between hub1-1 and elongata (elo) showed ...
Circadian clocks, found widely in nature, act to coordinate biological processes with rhythmic changes in the environment. Light input plays an important role in adjusting the clocks phase as well as maintaining its pace, allowing for perception of both daily and seasonal information (Aschoff, 1979). The central biological oscillator interprets this environmental information and transmits the signal to a diverse set of outputs. A substantial portion of the Arabidopsis (Arabidopsis thaliana) transcriptome is clock regulated, with estimates ranging from 2% to 36% of expressed genes (Harmer et al., 2000; Schaffer et al., 2001; Michael and McClung, 2003a; Edwards et al., 2006; M.F. Covington and S.L. Harmer, personal communication).. In the current model of the Arabidopsis oscillator, TIMING OF CHLOROPHYLL A/B BINDING PROTEIN/PSEUDO RESPONSE REGULATOR1 (TOC1/PRR1) is believed to act as part of a central negative feedback loop with CIRCADIAN CLOCK ASSOCIATED (CCA1) and LATE ELONGATED HYPOCOTYL (LHY; ...
The majority of cells in the body have an internal clock which controls cell cycle factors. However, the internal clock of cancer cells is often non-functioning or malfunctioning.. In the study, the team compared the growth and cell cycle events of B16 melanoma cells and tumors with either a functional or dysfunctional clock. The team demonstrated that clock genes are suppressed in B16 melanoma cells and B16 tumors.. The team then went on to successfully adjust the internal clocks of melanoma B16 cells and human colon carcinoma cells, as to make them function normally. The repair, carried out in tissue cultures and mice, slowed the growth of tumor tissue; a week post-treatment, the treated tumor was two thirds smaller compared to the control tumor.. "There were indications suggesting that the malfunctioning clock contributed to rapid tumor growth, but this had never been demonstrated. Thanks to the use of a chemical or a thermic treatment, we succeeded in repairing these cells clock and ...
Further clues into the regulation of circadian clocks are the subject of two reports. In plants and insects, cryptochromes (CRYs) are activated by light, and in the fruit fly Drosophila, CRY blocks the negative feedback action of the PER-TIM complex. Griffin et al. 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. In Drosophila, three of the critical clock genes, period (per), timeless (tim), and Drosophila Clock (dClk), are expressed rhythmically. In their study of the cycling of dClk, Glossop et al. 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.. Glossop, N.R.J., Lyons, L.C., and Hardin. P.E. (1999) ...
Both epidemiological and clinical data suggest circadian involvement in the predisposition, etiology, and progression of immune-related morbidities, such as cancer and autoimmune diseases (37, 38). Inflammatory diseases, in particular, exhibit strong time-of-day symptoms. For example, rheumatoid arthritis has a strong diurnal variation in disease expression, which is accompanied by fluctuations in circulating IL-6 concentration (39). LPS-induced endotoxin shock displays temporal dependency (40), and circadian disruption mimicking jet lag can greatly magnify LPS response (41). According to recent evidence, components of the circadian clock regulate the expression of innate immune molecules, such as proinflammatory cytokines (42) and pattern recognition receptors (14). Rev-erbα is a key clock gene that controls inflammatory cytokine genes, including Il6, in macrophages, indicating that it negatively regulates the inflammatory responses in macrophages (11). In the current study, we found that ...
As a matter of fact, the notion of an internal clock as the sole timing element does not reflect the complexity of the real circumstances. "The daily behaviour of living organisms is a combination of immediate responses to changes in the environment and processes controlled by the circadian clock," says Helfrich-Förster. These two protagonists interact to help organisms adjust to their environment in an optimal way. For example, an animal whose eyes are not adapted to darkness will stop its movements after nightfall. And ideally its circadian clock will make the animal stop its activities before it is dark the next day.. The researchers studied the mechanisms and protagonists involved in these complex processes and the way they interact using the example of the fruit fly. The study looked at healthy flies, clockless flies, eyeless flies and flies lacking other timing-related switches. During the laboratory experiments they were exposed to different light conditions: simulated dusk, almost ...
Our results demonstrate that mammalian alternative splicing is regulated by both the circadian clock and feeding. Regulation by such oscillating physiological processes adds a novel temporal dimension to the regulation of alternative splicing, distinct from that involved in both acute and chronic responses to the environment. Circadian regulation of alternative splicing occurred in a tissue-dependent manner and, similarly to circadian mRNA abundance, we anticipate that the circadian regulation of alternative splicing will be important to tissue identity and function. Moreover, the circadian clock frequently modulates physiological systems so that they respond differently to acute stimuli at different times of the day. For example, mice display circadian variation in the ability to consolidate memories in response to hippocampal-dependent fear conditioning, responding less well when conditioned during the subjective night [45]. Furthermore, the susceptibility of mice to Escherichia coli ...
Structural biologists have made important progress towards better understanding the functioning of the circadian clock. The circadian or inner clock coordinates the sleep-wake rhythm and many other body processes that regulate, ...
In the classical view of circadian clock organization, the daily rhythms of most organisms were thought to be regulated by a central, master pacemaker, usually located within neural structures of the animal. However, with the results of experiments performed in zebrafish, mammalian cell lines and, more recently, mammalian tissues, this view has changed to one where clock organization is now seen as being highly decentralized. It is clear that clocks exist in the peripheral tissues of animals as diverse as Drosophila, zebrafish and mammals. In the case of Drosophila and zebrafish, these tissues are also directly light-responsive. This light sensitivity and direct clock entrainability is also true for zebrafish cell lines and early-stage embryos. Using luminescent reporter cell lines containing clock gene promoters driving the expression of luciferase and single-cell imaging techniques, we have been able to show how each cell responds rapidly to a single light pulse by being shifted to a common ...
This weeks GARNet research roundup again features papers on a variety of topics. First is work from the University of Leeds that investigates the physical properties of callose:cellulose hydrogels and the implication for cell wall formation. Second is work from the University of York that assesses the role of the HSP90.2 protein in control of the circadian clock. The third paper features GARNet committee member Sarah McKim and looks at the genetic control of petal number whilst the next paper from the Universities of Warwick and Glasgow includes a proteomic analysis of different types of secretory vesicles.. The next two papers look at different aspects of hormone signaling. Firstly Alistair Hetherington from the University of Bristol is a co-author on a study that looks at the role of the BIG protein whilst Simon Turners lab in Manchester investigates the role of ABA in xylem fibre formation.. The penultimate paper includes Lindsey Turnbull from the University of Oxford and looks at the ...
Diurnal patterns of gene transcription are often conferred by complex interactions between circadian clock control and acute responses to environmental cues. Arabidopsis thaliana GIGANTEA (GI) contributes to photoperiodic flowering, circadian clock control, and photoreceptor signaling, and its transcription is regulated by the circadian clock and light. We used phylogenetic shadowing to identify three evolutionarily constrained regions (conserved regulatory modules [CRMs]) within the GI promoter and show that CRM2 is sufficient to confer a similar transcriptional pattern as the full-length promoter. Dissection of CRM2 showed that one subfragment (CRM2-A) contributes light inducibility, while another (CRM2-B) exhibits a diurnal response. Mutational analysis showed that three ABA RESPONSE ELEMENT LIKE (ABREL) motifs in CRM2-A and three EVENING ELEMENTs (EEs) in CRM2-B are essential in combination to confer a high amplitude diurnal pattern of expression. Genome-wide analysis identified ...
The ubiquitin ligases CUL-3 and SLMB collaborate to regulate the Drosophila circadian clock by controlling TIMELESS oscillations.
...The circadian clocks that control and influence dozens of basic biolog...,Snooze,button,on,biological,clocks,improves,cell,adaptability,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
Sundowning or sundown syndrome causes a sudden worsening of confusion, agitation, and aggression in patients with Alzheimers disease and dementia, which was found to be governed by the bodys internal biological clock.
Circadian clocks synchronize cellular metabolism to the diurnal light cycle. In humans, our biological clocks impact many aspects of our physiology, including s...
BMAL1 can form heterodimers with either CLOCK or NPAS2, which act redundantly but show different tissue specificity. The BMAL1:CLOCK and BMAL1:NPAS2 heterodimers activate a set of genes that possess E-box elements (consensus CACGTG) in their promoters. This confers circadian expression on the genes. The PER genes (PER1, PER2, PER3) and CRY genes (CRY1, CRY2) are among those activated by BMAL1:CLOCK and BMAL1:NPAS2. PER and CRY mRNA accumulates during the morning and the proteins accumulate during the afternoon. PER and CRY proteins form complexes in the cytosol and these are bound by either CSNK1D or CSNK1E kinases which phosphorylate PER and CRY. The phosphorylated PER:CRY:kinase complex is translocated into the nucleus due to the nuclear localization signal of PER and CRY. Within the nucleus the PER:CRY complexes bind BMAL1:CLOCK and BMAL1:NPAS2, inhibiting their transactivation activity and their phosphorylation. This reduces expression of the target genes of BMAL1:CLOCK and BMAL1:NPAS2 ...
ARM] 4550/1: sched_clock on PXA should cope with run time clock rate selection The previous implementation was relying on compile time optimizations based on a constant clock rate. However, support for different PXA flavors in the same kernel binary requires that the clock be selected at run time, so here it is. Lets move this code to a more appropriate location while at it. Signed-off-by: Nicolas Pitre ,[EMAIL PROTECTED], Signed-off-by: Russell King ,[EMAIL PROTECTED], --- arch/arm/mach-pxa/generic.c , 62 ------------------------------------------- arch/arm/mach-pxa/time.c , 39 +++++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 62 deletions(-) diff --git a/arch/arm/mach-pxa/generic.c b/arch/arm/mach-pxa/generic.c index 5510f6f..9d6a2c0 100644 --- a/arch/arm/mach-pxa/generic.c +++ b/arch/arm/mach-pxa/generic.c @@ -25,10 +25,6 @@ #include ,linux/pm.h, #include ,linux/string.h, -#include ,linux/sched.h, -#include ,asm/cnt32_to_63.h, -#include ,asm/div64.h, - #include ,asm/hardware.h, ...
Science & Biotech Career Center - Free Listing of Postdoc, Faculty Positions, Academic and Industrial Jobs
DICER1 activity, was decreased. Importantly, single channel analysis in amphibian renal cells exhibited a dramatic decrease in the number of patches with observable ENaC current following CK1/ inhibition. The present study shows for the first time that CK1/ inhibition and impaired Per1 nuclear access results in decreased ENaC expression and ENaC activity, providing further support for direct control of ENaC by the circadian clock. for 10 min. Cells were resuspended in sucrose (10 mM Tris, 1 mM EDTA, 50 mM sucrose) and homogenized. The same level of sucrose (10 mM Tris, 1 mM EDTA, 250 mM sucrose) was added, accompanied by extra homogenization. Nuclei had been pelleted at 1,000 for 10 min and discarded. Organelles had been pelleted at 10,000 for 20 min and discarded. Supernatants had been centrifuged at >60,000 for 18 h. Membrane protein pellets were resuspended in 50 l of phosphatase and sucrose and protease inhibitors. Protein concentrations had been after that quantified by BCA assay (Pierce). ...
In 2012, a group led by Thomas P. Burris, then at Scripps Research Institute Florida and now at St. Louis University, designed and synthesized SR9009 and SR9011 to activate REV-ERB receptors (Nature 2012, DOI: 10.1038/nature11030). They showed that the compounds had metabolic effects-obese mice treated with the compounds lost weight. Based on previously observed associations between the circadian clock and cancer, Sulli, Panda, and coworkers speculated that the compounds might affect cancer cell viability as well. Panda notes that patents for the compounds are owned by Scripps and that "there is no immediate commercialization plan from Salk.". ...
Circadian clocks keep us, and our plants, reasonably attuned to the cycle of days and nights. Analyses of the molecules in the plant Arabidopsis that achieve this steady coordination have led to interlocking networks of logic and feedback loops of gene regulation. Pruneda-Paz et al. (see the Perspective by McClung) have now used a targeted genomics approach with yeast to add another molecule to the game: the transcription factor CHE. CHE binds to already known clock components of Arabidopsis and forms a linkage that was predicted but not yet closed, namely, bringing together a known clock component, TOC1, with its expected target gene, CCA1.. J. L. Pruneda-Paz, G. Breton, A. Para, S. A. Kay, A functional genomics approach reveals CHE as a component of the Arabidopsis circadian clock. Science 323, 1481-1485 (2009). [Abstract] [Full Text]. C. R. McClung, Linking the loops. Science 323, 1440-1441 (2009). [Summary] [Full Text]. ...
King DP, Zhao Y, Sangoram AM, Wilsbacher LD, Tanaka M, Antoch MP, Steeves TD, Vitaterna MH, Kornhauser JM, Lowrey PL, Turek FW, Takahashi JS. Cell. 1997;89(4):641-53. Genetic mapping and sequencing in mice confirmed the identification of the mammalian gene, clock, involved in the circadian system. A comparison of the nucleotide sequence of the wildtype gene with…
If you are a society or association member and require assistance with obtaining online access instructions please contact our Journal Customer Services team ...
Drosophila fruit flies are so named after the Latin for "dew loving" because they are more active at dawn and dusk. This strong sense of circadian rhythm (the 24 hour time cycle) is generated by a clock that ticks in the brain of all animals including humans.. The flys clock consists of about one hundred neurons in its 100,000-neuron brain, which can fit on a pin head. Inside each clock neuron is a "molecular clock" that consists of clock genes, which switch each other on and off every night and day.. Writing in the journal PNAS today, a team of researchers, led by Dr Edgar Buhl and Dr James Hodge from the University of Bristol in collaboration with Professor Ralf Stanewskys group at UCL, explain how they identified three novel proteins that act together on the surface of clock neurons to make the clock light responsive.. "To be useful for an organism, circadian clocks need to be synchronized (or reset) to the natural environment cycles of light and temperature, much like you need to reset ...
Circadian clocks have become popular systems for studying the relationship between gene-protein dynamics and phenotype. The molecular machinery underlying these networks has been relatively well characterized, and this has led to great interest in developing predictive computational models of the clock. Such models are usually formulated as sets of DEs. The high level of biochemical detail afforded by this approach has allowed DE models to successfully address a range of issues regarding the functional relationship between the architecture of the clock and circadian homeostasis. One homeostatic mechanism that has been comprehensively investigated from a theoretical perspective is temperature compensation. By assuming that certain subsets of a circuits kinetic parameters are temperature-dependent, temperature has been incorporated into a number of circadian DE models, ranging from minimal circuits built on the Goodwin oscillator [15,23,58] to more detailed formulations that explicitly model the ...
The Buccaneers announced this morning that theyll take a look at defensive end DaQuan Bowers in practice this week, starting the clock on a remarkable recovery from what was thought to be a season-ending injury.
According to the Centers for Disease Control and Prevention (CDC), around 30 percent of the adult population reports that they suffer from joint discomfort. While the reasons people have it may vary, there is now a new product on the market that will help them take on their joint problems, as well as turn back the clock on aging, so they not only feel younger, but look younger, too.. "Everyone looks for the fountain of youth so they can improve their mobility as well as reduce wrinkles," explained Asma Ishaq, president of Jusuru International, a company that develops nutraceuticals and dietary supplements. "We have created exactly what people have been looking for, and its worked time after time in clinical studies.". The new super ingredient scientifically developed by the company is called Liquid BioCell™, which is a naturally occurring matrix of hydrolyzed collagen, hyaluronic acid (HA), and chondroitin sulfate, all key components of healthy joints and supple skin. The patented formula has ...
... ,Configurable Desktop Clock 1.1 is Clock Utility to Display Configurable Clock on Desktop.
Nakamichi, Norihito et al "PSEUDO-RESPONSE REGULATORS 9, 7, and 5 Are Transcriptional Repressors in the Arabidopsis Circadian Clock." The Plant Cell 22.3 (2010): 594-605. Web. 27 Feb. 2020. ...
In ultra-deep submicron VLSI designs, clock network layout plays an increasingly important role on determining circuit quality indicated by timing, power c
A circadian oscillation can be reconstituted in vitro from three proteins that cycles with a period of ∼ 24 h. Two recent studies provide surprising biochemical answers to why this remarkable oscillator has such a long time constant and how it can switch effortlessly between alternating enzymatic modes.. ...
Sigma-Aldrich offers abstracts and full-text articles by [Hiromitsu Negoro, Akihiro Kanematsu, Masao Doi, Sylvia O Suadicani, Masahiro Matsuo, Masaaki Imamura, Takeshi Okinami, Nobuyuki Nishikawa, Tomonori Oura, Shigeyuki Matsui, Kazuyuki Seo, Motomi Tainaka, Shoichi Urabe, Emi Kiyokage, Takeshi Todo, Hitoshi Okamura, Yasuhiko Tabata, Osamu Ogawa].
50 LIST OF REFERENCES Alabad, D., Oyama, T., Yanovsky, M.J., Harmon, F. G., Ms, P. and Kay, S.A. (2001) reciprocal regulation between TOC1 and LHY/CCA1 within the Arabidopsis circadian clock. Science 293, 880-883. Alabad, D, Yanovsky, M.J., Ms, P., Harmer, S.L. and Kay, S.A. (2002) Critical role of CCA1 and LHY in maintaining circadian rhythmicity in Arabidopsis. Curr. Biol 12, 757-761. Albert, V.A., Soltis, D.E., Carlson, J.E., Farmer ie, W.G., Wall, P.K., Ilut, D.C., Solow, T.M., Mueller, L.A., Landherr, L.L., Hu, Y., Buzgo, M., Kim, S., Yoo, M.J., Frohlich, M.W., Perl-Treves, R., Schlarbaum, S.E., Bliss, B. J., Zhang, X., Tanksley, S.D., Oppenheimer, D.G., Soltis, P.S., Ma, H., dePamphilis, C.W., and Leebens-Mack, J.H. (2005) Floral gene resources from basal angiosperms for compar ative genomics research. BMC Plant Bio. 5, 5-20. Allada, R., Emery, P., Takahashi, J.S., and Ro sbash, M. (2001) Stopping time: The genetics of fly and mouse circadian cloc ks. Annu. Rev. Neurosci. 24, 1091-1119. ...
New discoveries about the circadian-clock machinery in the precursors to fat cells may explain why shift workers are prone to metabolic diseases, such as diabetes, a Stanford study finds.
Technology Networks is an internationally recognised publisher that provides access to the latest scientific news, products, research, videos and posters.
Bacteria inhabit most tissues in the human body, and genes from some of these microbes have made their way to the human genome. Could this genetic transfer contribute to diseases such as cancer?. 3 Comments. ...
Daily News German Scientists Resign from Elsevier Journals Editorial Boards These researchers join around 200 research institutions that have cut ties with the publishing giant to support the ongoing push for open access and favorable pricing.. ...
The 2305B is a high-speed phase-lock loop (PLL) clock buffer, designed to address high-speed clock distribution applications. The zero delay is achieved by aligning the phase between the incoming clock and the output clock, operable within the range of 10 to 133MHz. The 2305B is an 8-pin version of the 2309B. The 2305B accepts one reference input, and drives out five low skew clocks. The -1H version of this device operates, up to 133MHz frequency and has a higher drive than the -1 device. All parts have on-chip PLLs which lock to an input clock on the REF pin. The PLL feedback is on-chip and is obtained from the CLKOUT pad. In the absence of an input clock, the 2305B enters power down. In this mode, the device will draw less than 25μA, the outputs are tri-stated, and the PLL is not running, resulting in a significant reduction of power. The 2305B is characterized for both Industrial and Commercial operation ...
The 2305B is a high-speed phase-lock loop (PLL) clock buffer, designed to address high-speed clock distribution applications. The zero delay is achieved by aligning the phase between the incoming clock and the output clock, operable within the range of 10 to 133MHz. The 2305B is an 8-pin version of the 2309B. The 2305B accepts one reference input, and drives out five low skew clocks. The -1H version of this device operates, up to 133MHz frequency and has a higher drive than the -1 device. All parts have on-chip PLLs which lock to an input clock on the REF pin. The PLL feedback is on-chip and is obtained from the CLKOUT pad. In the absence of an input clock, the 2305B enters power down. In this mode, the device will draw less than 25μA, the outputs are tri-stated, and the PLL is not running, resulting in a significant reduction of power. The 2305B is characterized for both Industrial and Commercial operation ...
Reetika Rawat, Nozomu Takahashi*, Polly Yingshan Hsu*, Matthew A. Jones, Jacob Schwartz, Michelle R. Salemi, Brett S. Phinney, and Stacey L. Harmer. "REVEILLE8 and PSEUDO-REPONSE REGULATOR5 form a negative feedback loop within the Arabidopsis circadian clock" PLoS Genetics. (2011) *contributed equally. LINK ...
Roles of Dec1 and Dec2 in the core loop of the circadian clock, and clock outputs to metabolism. [Emerging Frontiers in Brain Research: Crossroads of metabolic regulaltion, stress response and disease. The 11th Meeting of Hirosaki International Forum of Medical Science. Communication Center of Hirosaki University School of Medicine. March 27-28,2009. Hirosaki, Japan.] (2010 ...
Cuesta, M., Cermakian, N., Boivin, D.B. (2013) Circadian clock genes and psychiatric disorders. In: The genetic basis of sleep and sleep disorders, Eds. P. Shaw, M. Tafti, M. Thorpy, University of Cambridge Press, Chapter 33, pp. 351-364. ...
Cuesta, M., Cermakian, N., Boivin, D.B. (2013) Circadian clock genes and psychiatric disorders. In: The genetic basis of sleep and sleep disorders, Eds. P. Shaw, M. Tafti, M. Thorpy, University of Cambridge Press, Chapter 33, pp. 351-364. ...
Check out this incredible interview with Dr. Michael Fossel as he talks about how we can reverse all chronic disease within just a couple of years and also, DOUBLE our life spans!
The first day of shooting turned out to be one of my worst days on set ever, says The Square DP Fredrik Wenzel. Heres how he weathered the storm.
Has anyone managed to sync time code between two EX1s? Heres how I tried... I set my timecode to CLOCK on both cams and attempted to SET clocks on
These clock-like mutational processes could ultimately be responsible for a large proportion of human cancer and contribute to human ageing.
Like almost all light-sensitive living beings, human beings follow biological rhythms set on a period of about 24 hours. The circadian clock (from Latin
Véronique is getting ready for a meeting. While noticing the time in the mirror on her pendant clock, she realizes that it is time to leave. When she looks through her window at the clock on the church steeple, she notices that she still has one hour before leaving. Question: What time is it on the church steeples clock? See answer ...
Clary. I was sat in the centre of the training gym, facing the door; my fingers toyed with the edge of my sweats. I glanced at the clock on the wall; Jace was half an hour late. Jace is never late! He had said that he had to go out and pick up something, he never said what. Maybe…I pushed the thought out of my mind before it could weave itself into the forefront of my conscious. Jace wouldnt…would he? I cursed and stood, stretching my limbs like a cat. Id already done the stretches that Jace had drilled into me. I shuddered at the memory of those arduous training sessions. I glanced again at the clock; it seemed to be laughing at me.. "Its thirty seconds later than you last checked you bint!" I chuckled at the thought of a clock actually insulting me.. I jogged back to my room, and checked my phone which was on my bedside table. Nothing.. Worry was starting to pull on my heart strings now. Maybe the Inquisitors back for revenge…Snapping out of my reverie, I walked evenly to the library ...
... is critical for learning, wakefulness, sleep, mood, hormonal regulation and maintenance of the circadian clock.
PER3 antibody (period circadian clock 3) for IHC-P, WB. Anti-PER3 pAb (GTX54605) is tested in Human, Mouse, Rat samples. 100% Ab-Assurance.
Can exercise keep you young? This is the question from the below article... I can definitely tell you that the answer is YES! I can attest that exercise has turned back the clock on me. Its been 3 years since I started weight lifting and have never been in a better shape than now. Not in my teens…
PrimaDerm Retinol Cream uses one of the top ingredients in the skin care world to resurface your skin and turn back the clock on aging. Get a trial here!
TY - JOUR. T1 - Inhibition of protein kinase A phase delays the mammalian circadian clock. AU - Lee, Jennifer M.. AU - Schak, Kathryn M.. AU - Harrington, Mary E.. PY - 1999/7/24. Y1 - 1999/7/24. N2 - The suprachiasmatic nuclei (SCN) contain the mammalian circadian clock whose rhythm of firing rate can be recorded in vitro for several days. Application of a protein kinase A (PKA) inhibitor onto the SCN at Zeitgeber time (ZT) 10 on the first day in vitro phase delayed the rhythm of firing rate expressed by SCN neurons on the subsequent day in vitro. Application of the inhibitor (Rp-cAMPS) at other circadian phases did not phase shift the rhythm. These results suggest that during approximately 1 h in the late subjective day the presence and activity of PKA plays a role in setting the phase of the mammalian circadian clock.. AB - The suprachiasmatic nuclei (SCN) contain the mammalian circadian clock whose rhythm of firing rate can be recorded in vitro for several days. Application of a protein ...
Circadian clocks are fundamental properties of all eukaryotic organisms and at least some prokaryotic organisms. Recent studies in our laboratory have shown that the gastrointestinal system contains a circadian clock that controls many, if not all, aspects of gastrointestinal function. We now report that at least one species of intestinal bacteria, Enterobacter aerogenes, responds to the pineal and gastrointestinal hormone melatonin by an increase in swarming activity. This swarming behavior is expressed rhythmically, with a period of approximately 24 hrs. Transformation of E. aerogenes to express luciferase with a MotA promoter reveals circadian patterns of bioluminescence that are synchronized by melatonin and whose periods are temperature compensated from 26°C to 40°C. Bioinformatics suggest similarities between the E. aerogenes and cyanobacterial clocks, suggesting the circadian clock may have evolved very early in the evolution of life. They also point to a coordination of host circadian ...
A programmable clock generator circuit receives control signals and a global clock and generates a pulsed data clock and a scan clock in response to gating signals. The clock generator has data clock and scan clock feed-forward paths and a single feedback path. Delay control signals program delay elements in the feedback path and logic gates reshape and generate a feedback clock signal. The global clock and the feedback clock signal are combined to generates a pulsed local clock signal. A scan clock feed-forward circuit receives the local clock and generates the scan clock. A data clock feed-forward circuit receives the local clock and generates the data clock with a logic controlled delay relative to the local clock signal. The feedback clock is generated with controlled delay thereby modifying the pulse width of the data and scan clocks independent of the controlled delay of the data clock feed-forward path.
Fast shipping specials nohassle returns on. Come in a custom record clock movement with any. Independant component wall clocks, wall clock parts suppliers brings you a leading supplier of wall clock components products united states canada to search enter a few every purchase supports independent analog clock standard wall clock movements quick and anniversary clocks from designers such as a wall mantel clock components time systems after years franklin clocks today. Audio inwall kit ht2002whv1 at. Clocks component mechanism diy repair but they generally belong to set up wall clock wall and battery or call us at clockworks or call. Ebay. Wall lights at guaranteed low prices. Modern wall clocks large, sale every day with one now. Wall and desk clocks and manufacturing of contemporary modern wall clocks are in our large wall clock styles antique wall and wallmounted light fixtures free shipping on the newest designs for every day at save time the largest selection of wall clocks are bolder and ...
Transcriptional activator which forms a core component of the circadian clock. The circadian clock, an internal time-keeping system, regulates various physiological processes through the generation of approximately 24 hour circadian rhythms in gene expression, which are translated into rhythms in metabolism and behavior. It is derived from the Latin roots circa (about) and diem (day) and acts as an important regulator of a wide array of physiological functions including metabolism, sleep, body temperature, blood pressure, endocrine, immune, cardiovascular, and renal function. Consists of two major components: the central clock, residing in the suprachiasmatic nucleus (SCN) of the brain, and the peripheral clocks that are present in nearly every tissue and organ system. Both the central and peripheral clocks can be reset by environmental cues, also known as Zeitgebers (German for timegivers). The predominant Zeitgeber for the central clock is light, which is sensed by retina and signals directly to
The circadian rhythm, also called circadian clock or just inner clock, is the endogenous capability of an organism to retain a 24 h rhythm without being exposed to environmental stimuli that indicate the time of day. Animals, plants and even fungi generate a circadian rhythm and plays a major role in daily live. For humans it is the mechanism to regulate sleep and wakefulness. Interestingly, during the first half year of life, as infants, humans do not have a working circadian rhythm, which explains why babies have an erratic sleeping pattern. They wake up in the middle of the night and are wide awake, much to the suffering of the parents. At around three to six months of age, the circadian clock starts to get established, and babies begin to sleep at night and are awake during the day. How are sleep and wakefulness regulated?. There are two mechanisms or systems that take care of sleep and wakefulness. This first is the "sleep and wake homoeostasis", which is a balance-system of sleep and ...
Circadian rhythm is an internal biological clock, which enables to sustain an approximately 24-hour rhythm in the absence of environmental cues. In mammals, the circadian clock mechanism consists of cell-autonomous transcription-translation feedback loops that drive rhythmic, 24-hour expression patterns of core clock components. The first negative feedback loop is a rhythmic transcription of period genes (PER1, PER2, and PER3) and chryptochrome genes (CRY1 and CRY2). PER and CRY proteins form a heterodimer, which acts on the CLOCK/BMAL1 heterodimer to repress its own transcription. PER and CRY proteins are phosphorylated by casein kinase epsilon (CKIepsilon), which leads to degradation and restarting of the cycle. The second loop is a positive feedback loop driven by the CLOCK/BMAL1 heterodimer, which initiates transcription of target genes containing E-box cis-regulatory enhancer sequences ...
The rhythmic genes we have identified under LD and DD conditions display bone fide rhythmic expression. The inclusion of seven known rhythmic genes (per, tim, vri, Clk, Dreg-2, cry, and takeout) in the set of 72 diurnally oscillating genes and four (per, tim, vri, and Clk) in the set of 22 circadianly oscillating genes provides confidence that the autocorrelation method we applied identifies rhythmic gene expression with fidelity.. The true number of circadianly regulated genes in Drosophila can only be estimated; the accuracy of any estimate depends on both methodological constraints and assumptions used in the data analysis. Our estimates of 72-200 robustly oscillating genes in LD 12:12 and a minimum of 22 genes in DD likely underestimate the true number of oscillating genes in the fly head. First, by necessity the choices of A0 minima were determined empirically. In the absence of true positive controls (i.e., rhythmically spiked foreign, polyadenylated message), we relied on the reproducible ...
A single 2 hour bright light pulse at night combined with a 4 hour delay of the sleep/dark episode delayed the human circadian clock an average of ~1.5 hours. We also observed individual differences in the magnitude of the phase delay, from virtually no delay to up to 2 hours. These findings more clearly delineate the rate at which the circadian clock can be delayed in a practical protocol that could be used in the real world. Previous studies utilizing a single bright light pulse ending late at night with subjects waking at their habitual time (sleep episode truncated) have reported phase delays of about 1 hour [24, 25]. Studies in which a single long duration bright light pulse (, 6 hours, up to ~10,000 lux) was paired with 2 days of a large delay (,8 hours) in the sleep/dark episode have reported phase delays of up to 3 hours [9, 12, 27, 28]. Although a 3 hour phase delay from a single day of light treatment is robust, such a large shift in the sleep schedule may not be appealing or feasible ...
Circadian rhythms modulate growth and development in all organisms through interlocking transcriptional-translational feedback loops. The transcriptional loop involves chromatin modifications of central circadian oscillators in mammals and plants. However, the molecular basis for rhythmic epigenetic modifications and circadian regulation is poorly understood. Here we report a feedback relationship between diurnal regulation of circadian clock genes and histone modifications in Arabidopsis. On one hand, the circadian oscillators CCA1 and LHY regulate diurnal expression of genes coding for the eraser (JMJ14) directly and writer (SDG2) indirectly for H3K4me3 modification, leading to rhythmic H3K4me3 changes in target genes. On the other hand, expression of circadian oscillator genes including CCA1 and LHY is associated with H3K4me3 levels and decreased in the sdg2 mutant but increased in the jmj14 mutant. At the genome-wide level, diurnal rhythms of H3K4me3 and another histone mark H3K9ac are associated
Epigenetic Modulation of Circadian Rhythms: Bmal1 Gene Regulation. By Tatsunosuke Tomita and Yoshiaki Onishi. Circadian rhythms that function in behaviour and physiology have adaptive significance for living organisms from bacteria to humans and reflect the presence of a biological clock. The engine of circadian rhythms is a transcription-translation feedback loop that is fine-tuned by epigenetic regulation in higher eukaryotes. We elucidated the chromatin structure of the Bmal1 gene, a critical component of the mammalian clock system, and have continued to investigate transcriptional regulation including DNA methylation. Various ailments including metabolic diseases can disrupt circadian rhythms, and many human diseases are associated with altered DNA methylation. Therefore, regulated circadian rhythms are important for human health. Here, we summarise the importance of epigenetic clock gene regulation, including DNA methylation of the Bmal1 gene, from the viewpoint of relationships to ...
Many organisms have ≈24-h rhythms in metabolism, physiology, and behavior that are driven by cell autonomous circadian pacemakers (1). These circadian rhythms allow organisms to coordinate a myriad of physiological processes with the changing environment. In mammals, the circadian pacemaker is composed of interlocked transcription-translation feedback loops: the primary loop is composed of the basic helix-loop-helix transcription factors CLOCK and BMAL1, which drive transcription of the Period (Per1, Per2) and Cryptochrome (Cry1, Cry2) genes (1, 2). PER and CRY proteins form the negative limb of the feedback loop by inhibiting their own CLOCK:BMAL1-induced transcription; turnover of PER and CRY allows the cycle to begin anew. The interlocked loop consists of REV-ERB-α and RORα, which repress and activate the Bmal1 gene, thereby modulating its function (3, 4). Mutation or deletion of Clock (5), Bmal1 (6), Per1/2 genes (7, 8), or Cry1/2 (9, 10) genes results in behavioral arrhythmicity and ...
Apparatus and method support the synchronization and calibration of a plurality of clocks in a medical device system that may provide treatment to a patient with a nervous system disorder. The plurality of clocks, which may be located at different components of the medical device system, comprises a first clock and a second clock. The second clock may be synchronized to a first clock by disabling a run mode operation and setting the second clock to a selected time. When a reference time of the first clock approximately equals the selected time, the second clock enables the run mode operation. Additionally, a drift time that is indicative of a time difference between the first clock and the second clock is determined. If the drift time is greater than a predetermined amount, an indication to resynchronize the first and second clocks is provided.
A method for routing clock signals in an integrated circuit provides a hierarchical routing scheme in which the lowest level clock buffers are first placed row by row in preallocated locations and routed to the input pins of standard cells receiving the output clock signals of these clock buffers. Under the method, the number of clock buffers to be placed in each row is computed according to estimates of their load capacitances and expected wiring lengths within a window. The output buffers of the same clock signal are gridded or strapped together to minimize clock skew. A second level of clock buffers are then assigned to drive the lowest level buffers. The hierarchy can be extended to any number of higher levels, until clock signals are routed for the entire integrated circuit. The higher level clock signals can also be strapped or gridded to minimize clock skew.
Our possessions should tell people who we are. Let the items that sit on your desk let people who come into your office know what youre about. If you want a clock that lets everyone know youre a science super geek, then the Model AWK-105 Analog Voltmeter Clock is for you.. This clock looks like an analog voltmeter. Its right there in the name. In fact, at first glance, most people probably wouldnt even consider it was a clock. A clock it is though! It reads hours and minutes but on two separate faces. The hours are on the left side and the minutes are on the right side. From there on, its just like a normal clock.. This clock reads like any normal 12 hour clock, even though it looks just a bit different. It will give you down to the minute time and stay true unless theres a power outage. This clock is manually set so you can look forward to visiting it twice a year for Daylight Savings Time. The Model AWK-105 Analog Voltmeter Clock is $139.. ...
A 2/N mode dock generator that generates bus clock signals through the use of bus clock enable signals selecting bus clock pulses that are in phase and out of phase with a core clock signal. The clock generator maintains synchronization between the bus clock signal and the core clock signal so that they are always in a predetermined phase relationship.
Purpose: CLOCK and NPAS2, homologous circadian clock proteins, are expressed in the mammalian retina. However, their specific roles in retinal gene regulation or function have not been elucidated. This study was conducted to determine whether NPAS2 and CLOCK are co-expressed in retinal neurons and their effects on retinal gene expression and function.. Methods: Studies were performed using C57BL/6 wildtype (WT), Clock-/-, and Npas2-/- mice. Laser capture microdissection and quantitative real-time PCR were performed to isolate the ganglion cell layers (GCL) at five time points for transcription expression analyses for Npas2, Clock, and Adcy1. Luciferase reporter assay in NG108-15 cells was conducted to determine whether CLOCK/BMAL1 and/or NPAS2/BMAL1 heterodimers could activate the Adcy1 promoter. Contrast sensitivity was measured using optokinetic tracking at mid-day and mid-night time points, and scotopic and photopic electroretinograms (ERG) were recorded to measure retinal responses to ...
The circadian genetic machinery is so well conserved in the evolution that the study of Drosophila provides a cheap alternative to knockout experiments in rodents. Orthologs have been identified in mammals for most of the Drosophila circadian clock genes. In insects though, unlike in mammals, CRY1 function is light-dependent. Even cyanobacteria have a circadian genetic clock that can be reconstituted in vitro for detailed quantitative analysis and comparative simulations. One of the conclusions coming from studying cyanobacteria is that the TTFL clock may actually be a slave to a master biochemical oscillator called the PTO (post-translational oscillator) (Qin et al. 2010[1]). The initial suggestion on the role of biochemical oscillators came from the persistence of the circadian rhythm in conditions of inhibited transcription and translation (Iwasaki et al. 2005[2]). Beyond their circadian roles, the genes are also involved in other functions. Interestingly, cryptochromes have been shown to be ...
For each species, we generated a phase-ordered microarray time series covering one segmentation clock oscillation. For each embryo of each species, the posterior half of the right-hand side presomitic mesoderm (PSM) was surgically removed, leaving the rest of the embryo intact. RNA was then extracted from the dissected piece and amplified before hybridization of each sample individually on an Affymetrix GeneChip array (Fig. 1A). The remaining part of the dissected embryo was used to visualize the cyclic traveling wave, which propagates anteriorly along the PSM during one cycle of the segmentation clock. These dynamic stripes were detected by in situ hybridization (ISH) with the known cyclic genes Lfng for mouse and chick (Aulehla and Johnson, 1999; McGrew et al., 1998) and her7 (Oates and Ho, 2002) for zebrafish. Samples were then ordered chronologically a posteriori, within an oscillatory cycle, based on the anteroposterior position of the expression stripe along the PSM (Fig. 1B-D). Twenty-two ...
Drosophila melanogaster locomotor activity responds to different seasonal conditions by thermosensitive regulation of splicing of a 3′ intron in the period mRNA transcript. Here we demonstrate that the control of locomotor patterns by this mechanism is primarily light-dependent at low temperatures. At warmer temperatures, when it is vitally important for the fly to avoid midday desiccation, more stringent regulation of splicing is observed, requiring the light input received through the visual system during the day and the circadian clock at night. During the course of this study, we observed that a mutation in the no-receptor-potential-AP41 (norpAP41 ) gene, which encodes phospholipase-C, generated an extremely high level of 3′ splicing. This cannot be explained simply by the mutations effect on the visual pathway and suggests that norpAP41 is directly involved in thermosensitivity ...
A method of calibrating a first clock signal using a second clock signal and a plurality of calibration periods may include generating incremented counter values at a counter responsive to edges of the second clock signal. For at least two of the plurality of calibration periods, an initial incremented counter value from the counter may be stored in memory at an initial edge of the first clock signal for the respective calibration period, a final incremented counter value may be stored in memory at a final edge of the clock signal for the respective calibration period, and the at least two of the plurality of calibration periods may be overlapping with different initial and final edges of the first clock signal. For each of the plurality of calibration periods, a number of edges of the second clock signal occurring during the respective calibration period may be determined using the initial and final incremented counter values stored in memory. A relationship between the first and second clock signals
All cells possess a molecular circadian ?clock? thought to coordinate various aspects of the physiology and behavior of an animal with the light/dark cycle of the external world. Light is the principle cue entraining molecular clocks via the suprachiasmatic nucleus of the brain. Recent evidence however, has also implicated food-borne signals as external stimuli capable of resetting clocks in the periphery. The aim of this study was to investigate the impact of aberrant feeding on circadian energy metabolism in the rat by feeding a high fat diet and restricting feeding to the daylight hours. Here we show that rats on the daylight feeding and high-fat feeding schedules displayed various differences in metabolism including hormone and metabolite levels and gene and protein expression. In the liver the circadian expression pattern of molecular clock genes was completely reversed in response to the new feeding schedule. In contrast, circadian gene expression in muscle remained similar to an animal feeding ad
NIH Funding Opportunities and Notices in the NIH Guide for Grants and Contracts: Sleep disorders and circadian clock disruption in Alzheimers disease and other dementias of aging (R01 Clinical Trial Not Allowed) PAR-18-497. NIA
A video sub-system features reduced power consumption by periodically disabling the video controller clocks used for transferring pixel data to a screen. The video clocks are pulsed only when pixel data is being transferred to the screen, during the time that a horizontal line of pixels is being scanned on the screen. The video clocks are not pulsed during the horizontal and vertical blanking periods, when the electron beam in a cathode-ray-tube is being re-traced. The video clocks are also not pulsed during a recovery period for a flat-panel screen. A video memory contains pixel information for the entire screen and is controlled by a memory controller. The memory controller uses a memory clock to transfer all or part of a horizontal line of pixels to a video buffer. The pixel data is then read out of the video buffer to the screen in a serial fashion, synchronized to the video clock. Host data may be written to a host buffer using a bus clock from the host, and then written to the video memory using
Dartmouth researchers have found evidence of two circadian clocks working within the same tissue of the plant Arabidopsis thaliana; posted 05/07/03 by Sue Knapp
The anticipation of daily transitions like dawn and dusk by a circadian clock provides a fitness advantage in cyanobacteria, plants, fungi, and animals (Dodd et al. 2005; Green et al. 2002; Xu et al. 2011; Yerushalmi et al. 2011). Although the circadian clock comprises a highly interconnected network of transcriptional activators and repressors, this adaptation to a rhythmic environment has been maintained while the expansion of gene families and whole-genome duplication or triplication events have altered the balance between different clock components. With the advent of genome-sequencing platforms, we are now in an ideal position to study the evolutionary trajectory of clock gene families, including gene copy number variation, and the birth and death of new copies. Because of its network properties, the circadian clock constitutes a great model system in which to test the gene balance hypothesis. Indeed, Albert Blakeslee observed already in the early 1920s that plants with three copies of a ...
2. Time Clock Manager Pro 2.1 An employee time clock and a management tool. Its allows user to clock in/clock out. It works with touch screen monitors. Also has reports to show clocked in and clock out times. The application has integrated security and can work with networks... Details - Download Tags: time Clock Software , time , clock , manager , managerment , tool , employee , report , clockin , clockout , calculator , vsisystems , szamody ...
Wall clocks in hospitals large and small, as well as in colleges and universities, along with all major businesses, have a continuing need for wall clocks. It can be especially important to have clocks that keep good time and do not break down, so that hospital workers and office individuals are not disagreeing about whether the quitting time has actually arrived or not.. Even hospital purchasing organizations, procurement divisions of government, businesses and other organizations are always seeking to maintain and improve the systems in place to track time, and wall clocks, not surprisingly, are the clock of choice.. When it comes to accuracy, radio controlled or atomic clocks have gained much favor and general acceptance by major institutions. Many purchase just a few to test them out to ensure they will work well for them. There is also a technology known as an Autoset or Auto Set clock which is generally not an atomic, but does automatically move forward an hour and back an hour on the ...
13h à 14h Le séminaire de David Lubensky (University of Michigan) aura lieu dans lAmphi Urbain, ESPCI, 10 Rue Vauquelin 75005 All plants and (...)
Metabolic activities are regulated by the circadian clock, and disruption of the clock exacerbates metabolic diseases including obesity and diabetes. Transcriptomic studies in metabolic organs suggested that the circadian clock drives the circadian expression of important metabolic genes. Here we show that histone deacetylase 3 (HDAC3) is recruited to the mouse liver genome in a circadian manner. Histone acetylation is inversely related to HDAC3 binding, and this rhythm is lost when HDAC3 is absent. Diurnal recruitment of HDAC3 corresponds to the expression pattern of REV-ERBα, an important component of the circadian clock. REV-ERBα colocalizes with HDAC3 near genes regulating lipid metabolism, and deletion of HDAC3 or Rev-erbα in mouse liver causes hepatic steatosis. Thus, genomic recruitment of HDAC3 by REV-ERBα directs a circadian rhythm of histone acetylation and gene expression required for normal hepatic lipid homeostasis. In addition, we reported that the REV-ERBα paralog, REV-ERBβ also
1. Zheng X, Sehgal A (2012) Speed control: cogs and gears that drive the circadian clock. Trends Neurosci 35: 574-585. doi: 10.1016/j.tins.2012.05.007 22748426. 2. Hardin PE (2011) Molecular genetic analysis of circadian timekeeping in Drosophila. Adv Genet 74: 141-173. doi: 10.1016/B978-0-12-387690-4.00005-2 21924977. 3. Rothenfluh A, Young MW, Saez L (2000) A TIMELESS-independent function for PERIOD proteins in the Drosophila clock. Neuron 26: 505-514. 10839368. 4. Curtin KD, Huang ZJ, Rosbash M (1995) Temporally regulated nuclear entry of the Drosophila period protein contributes to the circadian clock. Neuron 14: 365-372. 7857645. 5. Ko HW, Kim EY, Chiu J, Vanselow JT, Kramer A, et al. (2010) A hierarchical phosphorylation cascade that regulates the timing of PERIOD nuclear entry reveals novel roles for proline-directed kinases and GSK-3beta/SGG in circadian clocks. J Neurosci 30: 12664-12675. doi: 10.1523/JNEUROSCI.1586-10.2010 20861372. 6. Chang DC, Reppert SM (2003) A novel C-terminal ...
The molecular clock of the fruit fly is sensitive to magnetic fields in a manner dependent on blue light and the photopigment cryptochrome.
In modern societies, the risk of developing metabolic disorders such as obesity or type-2 diabetes is associated with the prevalence of psychosocial stress. Therefore, an improved understanding of adaptive stress responses and their underlying molecular mechanisms is of high clinical interest. In response to an acute stressor, animals activate the sympathetic nervous system and the hypothalamus pituitary adrenal (HPA) axis releasing catecholamines and glucocorticoids (GCs) into the circulation. Recent data suggest that stress responses are also regulated by the endogenous circadian clock adapting physiology and behavior to the environmental changes brought about by the Earth s rotation around its axis. Thus, the timing of stress may critically affect adaptive responses to and the pathological effects of repetitive stressor exposure. We have studied the role of different tissue clocks on the regulation of HPA axis activity in mice. We further characterized the impact of predictable social defeat ...
It s always amazing to see something that looks so simple and see it transform into something well thought out and complex. That s exactly what s happening here with the Clock Clock. This is a huge what looks to be four-paneled clock that is actually made up of twenty-four small ones. Each panel is made up of 6 smaller clocks that have very basic faces, which adds a very interesting aesthetic.. Once the time changes, the hands on the panel in which a number is changing will all spin until all the hands meet to make the illusion of a large number. If you ve ever had the problem of needing to know what time it is and can t seem to find a clock, this may solve your problems as it s 51 x 18 . If you re late for anything you can t say you weren t paying attention to the time. This is actually at a gallery currently, but if you really want one, I m sure there are some fun tutorials online.. ...
Buy Ticking Clock Loops Pack by ShahruhAudio on AudioJungle. 4 various ticking clock loops Durations: ticking clock1 0:04 ticking clock2 0:08 ticking clock3 0:08 ticking clock4 0...
The role of DOMINO in regulation of circadian rhythms in Drosophila. Most organisms on earth use circadian clocks to modulate their bodily functions, thus adapting their metabolism, physiology and behavior to these daily environmental cycles. Malfunctions of circadian clocks are correlated with many human diseases. For example, disrupted circadian rhythms in shift workers are thought to increase the prevalence of cancers, cardiovascular diseases, diabetes and other metabolic diseases. Circadian clocks control rhythmic expression of around 10-15% of mammalian transcripts. The fruit fly Drosophila melanogaster is an excellent model to study circadian clock because of its well-characterized genome, powerful genetics tools, and high throughput automated behavioral assays. In addition, the core of the circadian pacemaker is highly conserved among species, and the molecular mechanisms of circadian clocks were, in great part, discovered in Drosophila. Studying circadian rhythms in Drosophila has ...
BACKGROUND:. Tremendous progress in the past few years has led to the identification of several circadian clock genes. This now makes it possible to determine how alterations of human circadian clock genes and their expression could lead to differences in circadian and sleep/wake cycle phenotypes. Of particular interest for understanding genetics of the human circadian system are individuals with sleep phase disorders, such as DSPS and advanced sleep phase syndrome (ASPS), because recent studies indicate a genetic basis for these disorders. While it is assumed that both ASPS and DSPS are disorders of circadian timing, little is known about how the circadian clock system, or its interaction with sleep processes, are affected in these individuals.. DESIGN NARRATIVE:. Participants will complete questionnaires and actigraphy to determine sleep patterns and quality. ...
Post-traumatic stress disorder (PTSD) is associated with impaired conditioned fear extinction learning, a ventromedial prefrontal cortex (vmPFC)-dependent process. PTSD is also associated with dysregulation of vmPFC, circadian, and glucocorticoid hormone function. Rats have rhythmic clock gene expression in the vmPFC that requires appropriate diurnal circulatory patterns of corticosterone (CORT), suggesting the presence of CORT-entrained intrinsic circadian clock function within the PFC. We examined the role of vmPFC clock gene expression and its interaction with CORT profiles in regulation of auditory conditioned fear extinction learning. Extinction learning and recall were examined in male rats trained and tested either in the night (active phase) or in the day (inactive phase). Using a viral vector strategy, Per1 and Per2 clock gene expression were selectively knocked down within the vmPFC. Circulating CORT profiles were manipulated via adrenalectomy (ADX) ± diurnal and acute CORT ...
The circadian clock allows plants to anticipate predictable daily changes in abiotic stimuli, such as light; however, whether the clock similarly allows plants to anticipate interactions with other organisms is unknown. Here we show that Arabidopsis thaliana (Arabidopsis) has circadian clock-mediated variation in resistance to the virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), with plants being least susceptible to infection in the subjective morning. We suggest that the increased resistance to Pst DC3000 observed in the morning in Col-0 plants results from clock-mediated modulation of pathogen associated molecular pattern (PAMP)-triggered immunity. Analysis of publicly available microarray data revealed that a large number of Arabidopsis defence-related genes showed both diurnal- and circadian-regulation, including genes involved in the perception of the PAMP flagellin which exhibit a peak in expression in the morning. Accordingly, we observed that ...
TY - JOUR. T1 - Functional analysis of the circadian clock gene period by RNA interference in nymphal crickets Gryllus bimaculatus. AU - Moriyama, Yoshiyuki. AU - Sakamoto, Tomoaki. AU - Matsumoto, Akira. AU - Noji, Sumihare. AU - Tomioka, Kenji. PY - 2009/5. Y1 - 2009/5. N2 - The circadian clock gene period (Gryllus bimaculatus period, Gbper) plays a core role in circadian rhythm generation in adults of the cricket Gryllus bimaculatus. We examined the role of Gbper in nymphal crickets that show a diurnal rhythm rather than the nocturnal rhythm of the adults. As in the adult optic lobes, Gbper mRNA levels in the head of the third instar nymphs showed daily cycling in light-dark cycles with a peak at mid night, and the rhythm persisted in constant darkness. Injection of Gbper double-stranded RNA (dsRNA) into the abdomen of third instar nymphs knocked-down the mRNA levels to 25% of that in control animals. Most Gbper dsRNA injected nymphs lost their circadian locomotor activity rhythm, while ...
Challenging the human circadian clock by daylight saving time and shift-work [Elektronische Ressource] / written by Thomas Kantermann : Challenging the human circadian clock by Daylight Saving Time and Shift-Work Academic Dissertation (Doctor rerum naturalium) At the Centre for Chronobiology Institute for Medical Psychology Ludwig-Maximilians-University Munich Written by Thomas Kantermann thBorn 26 of February, 1979 in Gütersloh Arbeit eingereicht am: 17.07.2008 1. Gutachter / Prüfer: Prof. Gisela Grupe 2. Gutachter /
OBJECTIVE: Physical activity and circadian rhythms are well-established determinants of human health and disease, but the relationship between muscle activity and the circadian regulation of muscle genes is a relatively new area of research. It is unknown whether muscle activity and muscle clock rhythms are coupled together, nor whether activity rhythms can drive circadian gene expression in skeletal muscle. METHODS: We compared the circadian transcriptomes of two mouse hindlimb muscles with vastly different circadian activity patterns, the continuously active slow soleus and the sporadically active fast tibialis anterior, in the presence or absence of a functional skeletal muscle clock (skeletal muscle-specific Bmal1 KO). In addition, we compared the effect of denervation on muscle circadian gene expression. RESULTS:We found that different skeletal muscles exhibit major differences in their circadian transcriptomes, yet core clock gene oscillations were essentially identical in fast and slow ...
AC (29) ADHD (30) affect (1) aging (22) Alzheimers (3) American Indians (1) anterior cinglate (1) APA (1) aphasia (5) apraxia (3) Aspergers (1) ATI (1) attention (56) attentional control (32) auditory (14) Auditory Neuroscience Lab (2) autism (6) automatic timing (8) background noise (1) basal ganglia (16) beat perception (4) beat production (4) biofeedback (1) book nook (21) BPR3 (1) brain structures (24) brain beat (1) brain carnival (34) brain clock (122) Brain Clock Blog (2) brain clock timing (2) brain facts (2) brain fitness (119) brain function (3) brain injury (25) brain location (28) Brain network integration (1) brain network segregation (1) brain networks (57) brain rhythm (20) brain structure (1) brain teasers (2) brain timing (1) brain training (14) brainstem (2) BRAMS lab (1) Brocas area (1) caffeine (1) CAPD (2) CAT (1) CBRM (1) cerebellum (17) cerebral palsy (2) CHC (1) CHC theory (11) CHC videos (1) circadian (4) classification (1) clinical disorders (3) clocks (1) CNTRICS (1) ...

Chronotherapeutic Drug Delivery Systems | OMICS InternationalChronotherapeutic 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 ...
more infohttps://www.omicsonline.org/open-access/chronotherapeutic-drug-delivery-systems-2157-7609-1000194.php?aid=65452

Role of Chronobiology as a Transdisciplinary Field of Research: Its Applications in Treating Mood Disorders - Balkan Medical...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 ...
more infohttp://balkanmedicaljournal.org/text.php?lang=en&id=1915

News Segments - MelatoninNews 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 ...
more infohttps://melatonin.com/index.php/news-segments-2/

chronobiologychronobiology

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 ...
more infohttp://www.denvernaturopathic.com/news/chronobiology.html

Awards - Canadian Society for ChronobiologyAwards - 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 ...
more infohttp://www.chronobiocanada.com/awards/

Circadian clock - WikipediaCircadian 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 ...
more infohttps://en.wikipedia.org/wiki/Circadian_clock

Yes, Archaea also have circadian clocks! | ScienceBlogsYes, 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): ...
more infohttps://scienceblogs.com/clock/2009/05/28/yes-archaea-also-have-circadia

Resonating circadian clocks enhance fitness in cyanobacteria | PNASResonating 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 ...
more infohttps://www.pnas.org/content/95/15/8660

Circadian clocks: Providing Feedback | Science SignalingCircadian 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 ...
more infohttp://stke.sciencemag.org/content/1999/5/tw7

Circadian clocks and pregnancy | Frontiers Research TopicCircadian 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 ...
more infohttps://www.frontiersin.org/research-topics/1010/circadian-clocks-and-pregnancy

Circadian Rhythms and Circadian Clock | NIOSH | CDCCircadian 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 ...
more infohttps://www.cdc.gov/niosh/emres/longhourstraining/clock.html

Circadian clock not essentialCircadian 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. ...
more infohttp://www.innovations-report.com/html/reports/life-sciences/circadian-clock-not-essential.html

How Our Circadian Clocks Regulate Energy MetabolismHow 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 ...
more infohttps://www.medindia.net/news/how-our-circadian-clocks-regulate-energy-metabolism-177702-1.htm

How circadian clocks communicate with each other | EurekAlert! Science NewsHow 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 ...
more infohttps://www.eurekalert.org/pub_releases/2017-05/uow-hcc053017.php

Molecular and Genetic Analysis of Mammalian Circadian Clocks | HHMI.orgMolecular 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 ...
more infohttps://www.hhmi.org/research/molecular-and-genetic-analysis-mammalian-circadian-clocks

Light and the Human Circadian Clock | SpringerLinkLight 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 ...
more infohttps://link.springer.com/chapter/10.1007%2F978-3-642-25950-0_13

Circadian clock cryptochrome proteins regulate autoimmunity | PNASCircadian 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 ...
more infohttps://www.pnas.org/content/114/47/12548.long

Unnatural light-dark cycles expose duelling circadian clocksUnnatural 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 ...
more infohttps://www.innovations-report.com/html/reports/life-sciences/report-28753.html

circadian clocks Protocols and Video...'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, ...
more infohttps://www.jove.com/keyword/circadian+clocks

Disruptions In Circadian Clock Have Health Consequences - RedorbitDisruptions 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 ...
more infohttps://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 tissueDartmouth 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 ...
more infohttp://www.dartmouth.edu/~news/releases/2003/may/050703.html

Circadian Clock Times Immune Response | Medpage TodayCircadian 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" ...
more infohttps://www.medpagetoday.com/infectiousdisease/vaccines/31235

Characterization of Peripheral Circadian Clocks in Adipose Tissues | DiabetesCharacterization 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. ...
more infohttp://diabetes.diabetesjournals.org/content/55/4/962

Kidneys circadian clock regulates drug disposition, blood component levelsKidneys' 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 ...
more infohttps://www.medicalnewstoday.com/articles/308808.php
  • 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)
  • 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)
  • 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)
  • 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)
  • 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)
  • 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)
  • 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)