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.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.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.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.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.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.Biological Clocks: The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.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.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.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.Chronobiology Disorders: Disruptions of the rhythmic cycle of bodily functions or activities.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.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.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)Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Darkness: The absence of light.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.Body Temperature: The measure of the level of heat of a human or animal.Sleep: A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.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).Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.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.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.Phototherapy: Treatment of disease by exposure to light, especially by variously concentrated light rays or specific wavelengths.Casein Kinase Iepsilon: A casein kinase I isoenzyme with specificity for proteins involved the regulation of the CIRCADIAN RHYTHM.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.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.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.FlavoproteinsWakefulness: A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.Hydrocortisone: The main glucocorticoid secreted by the ADRENAL CORTEX. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.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.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Behavior, Animal: The observable response an animal makes to any situation.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.Seasonal Affective Disorder: A syndrome characterized by depressions that recur annually at the same time each year, usually during the winter months. Other symptoms include anxiety, irritability, decreased energy, increased appetite (carbohydrate cravings), increased duration of sleep, and weight gain. SAD (seasonal affective disorder) can be treated by daily exposure to bright artificial lights (PHOTOTHERAPY), during the season of recurrence.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.Rod Opsins: Photosensitive proteins expressed in the ROD PHOTORECEPTOR CELLS. They are the protein components of rod photoreceptor pigments such as RHODOPSIN.Work Schedule Tolerance: Physiological or psychological effects of periods of work which may be fixed or flexible such as flexitime, work shifts, and rotating shifts.Nuclear 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.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.Oscillometry: The measurement of frequency or oscillation changes.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Corticosterone: An adrenocortical steroid that has modest but significant activities as a mineralocorticoid and a glucocorticoid. (From Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1437)Light Signal Transduction: The conversion of absorbed light energy into molecular signals.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.Dorsomedial Hypothalamic Nucleus: An aggregation of cells in the middle hypothalamus dorsal to the ventromedial nucleus and bordering the THIRD VENTRICLE.Sleep Deprivation: The state of being deprived of sleep under experimental conditions, due to life events, or from a wide variety of pathophysiologic causes such as medication effect, chronic illness, psychiatric illness, or sleep disorder.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.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.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.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.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.Basic Helix-Loop-Helix Transcription Factors: A family of DNA-binding transcription factors that contain a basic HELIX-LOOP-HELIX MOTIF.Ocular Physiological Phenomena: Processes and properties of the EYE as a whole or of any of its parts.Dyssomnias: A broad category of sleep disorders characterized by either hypersomnolence or insomnia. The three major subcategories include intrinsic (i.e., arising from within the body) (SLEEP DISORDERS, INTRINSIC), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm. (From Thorpy, Sleep Disorders Medicine, 1994, p187)Alpha Rhythm: Brain waves characterized by a relatively high voltage or amplitude and a frequency of 8-13 Hz. They constitute the majority of waves recorded by EEG registering the activity of the parietal and occipital lobes when the individual is awake, but relaxed with the eyes closed.Atrial Fibrillation: Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.Telemetry: Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)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.Mice, Inbred C57BLSaliva: The clear, viscous fluid secreted by the SALIVARY GLANDS and mucous glands of the mouth. It contains MUCINS, water, organic salts, and ptylin.Ganglionectomy: Removal of an autonomic or sensory ganglion by any means.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.Sleep Stages: Periods of sleep manifested by changes in EEG activity and certain behavioral correlates; includes Stage 1: sleep onset, drowsy sleep; Stage 2: light sleep; Stages 3 and 4: delta sleep, light sleep, deep sleep, telencephalic sleep.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.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.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Eating: The consumption of edible substances.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.Neurospora crassa: A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.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.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.Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.Phodopus: A genus of hamsters characterized by small size, very short tail, and short, broad feet with hairy soles.Vasoactive Intestinal Peptide: A highly basic, 28 amino acid neuropeptide released from intestinal mucosa. It has a wide range of biological actions affecting the cardiovascular, gastrointestinal, and respiratory systems and is neuroprotective. It binds special receptors (RECEPTORS, VASOACTIVE INTESTINAL PEPTIDE).Body Temperature Regulation: The processes of heating and cooling that an organism uses to control its temperature.Luminescent Measurements: Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.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.Sleep Disorders: Conditions characterized by disturbances of usual sleep patterns or behaviors. Sleep disorders may be divided into three major categories: DYSSOMNIAS (i.e. disorders characterized by insomnia or hypersomnia), PARASOMNIAS (abnormal sleep behaviors), and sleep disorders secondary to medical or psychiatric disorders. (From Thorpy, Sleep Disorders Medicine, 1994, p187)Sleep, REM: A stage of sleep characterized by rapid movements of the eye and low voltage fast pattern EEG. It is usually associated with dreaming.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.Solar Activity: Any type of variation in the appearance of energy output of the sun. (NASA Thesaurus, 1994)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.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.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.Animals, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.Aerospace Medicine: That branch of medicine dealing with the studies and effects of flight through the atmosphere or in space upon the human body and with the prevention or cure of physiological or psychological malfunctions arising from these effects. (from NASA Thesaurus)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.Electroencephalography: Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.Electrocardiography: Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.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.Electric Countershock: An electrical current applied to the HEART to terminate a disturbance of its rhythm, ARRHYTHMIAS, CARDIAC. (Stedman, 25th ed)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)Receptor, Melatonin, MT2: A melatonin receptor subtype primarily found expressed in the BRAIN and RETINA.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Hypothalamus: Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.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.Trans-Activators: Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.Eye ProteinsAnalysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Adrenocorticotropic Hormone: An anterior pituitary hormone that stimulates the ADRENAL CORTEX and its production of CORTICOSTEROIDS. ACTH is a 39-amino acid polypeptide of which the N-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotrophic activity. Upon further tissue-specific processing, ACTH can yield ALPHA-MSH and corticotrophin-like intermediate lobe peptide (CLIP).Lithium Compounds: Inorganic compounds that contain lithium as an integral part of the molecule.Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Pituitary-Adrenal System: The interactions between the anterior pituitary and adrenal glands, in which corticotropin (ACTH) stimulates the adrenal cortex and adrenal cortical hormones suppress the production of corticotropin by the anterior pituitary.Mammals: Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.

Effects of dispersed recreational activities on the microbiological quality of forest surface water. (1/9125)

The microbiological quality of forest surface waters in the Greenwater River watershed was examined to investigate the influence of heavy motorized camping in an area with no sanitary facilities. Indicator densities increased during weekend human-use periods when compared to weekdays. Increases in indicator densities were also noted downstream from heavily used camping areas when compared to upstream sites. Seasonal, weekly, and diurnal fluctuations in indicator densities were observed. This study suggests that potential health hazards exist in this watershed during periods of human use.  (+info)

High-linoleate and high-alpha-linolenate diets affect learning ability and natural behavior in SAMR1 mice. (2/9125)

Semipurified diets incorporating either perilla oil [high in alpha-linolenate, 18:3(n-3)] or safflower oil [high in linoleate, 18:2(n-6)] were fed to senescence-resistant SAMR1 mouse dams and their pups. Male offspring at 15 mo were examined using behavioral tests. In the open field test, locomotor activity during a 5-min period was significantly higher in the safflower oil group than in the perilla oil group. Observations of the circadian rhythm (48 h) of spontaneous motor activity indicated that the safflower oil group was more active than the perilla oil group during the first and second dark periods. The total number of responses to positive and negative stimuli was higher in the safflower oil group than in the perilla oil group in the light and dark discrimination learning test, but the correct response ratio was lower in the safflower oil group. The difference in the (n-6)/(n-3) ratios of the diets reflected the proportions of (n-6) polyunsaturated fatty acids, rather than those of (n-3) polyunsaturated fatty acids in the brain total fatty acids, and in the proportions of (n-6) and (n-3) polyunsaturated fatty acids in the total polyunsaturated fatty acids of the brain phospholipids. These results suggest that in SAMR1 mice, the dietary alpha-linolenate/linoleate balance affects the (n-6)/(n-3) ratio of brain phospholipids, and this may modify emotional reactivity and learning ability.  (+info)

Alteration of circadian time structure of blood pressure caused by night shift schedule. (3/9125)

The effects of night shift schedules on circadian time structure of blood pressure were studied in seven healthy young subjects by continuous monitoring of blood pressure every 30 min for 72 h. In the control experiment, subjects were instructed to sleep at regular times with the light off at 00.00 h and the light on at 07.00 h. In the shift experiment, they were instructed to go to bed at 06.00 h and wake up at 11.00 h. The circadian rhythm of blood pressure rapidly phase delayed by 3.5 h in the second night shift day as a group phenomenon. Individual differences in changes in power spectral patterns of blood pressure were found in the night shift schedule. Ultradian rhythmicity of blood pressure was more pronounced in three subjects, whereas the circadian rhythmicity was maintained in four subjects. These findings held when the adaptation to shift work was taken into account.  (+info)

Circadian variation in the expression of cell-cycle proteins in human oral epithelium. (4/9125)

At the tissue level, there is experimental and clinical data to suggest a cytokinetic coordination of the cell cycle with a greater proportion of cycling cells entering S-phase and mitosis at specific times of the day. The association of certain cell-cycle proteins with defined events in the cell cycle is well established and may be used to study the timing of cell-cycle phases over 24 hours. In this study oral mucosal biopsies were obtained from six normal human volunteers at 4-hour intervals, six times over 24 hours. Using immunohistochemistry, the number of positive cells expressing the proteins p53, cyclin-E, cyclin-A, cyclin-B1, and Ki-67 was determined for each biopsy and expressed as the number of positive cells per mm of basement membrane. We found a statistically significant circadian variation in the nuclear expression of all of these proteins with the high point of expression for p53 at 10:56 hours, cyclin-E at 14:59 hours, cyclin-A at 16:09 hours, cyclin-B1 at 21:13 hours, and Ki-67 at 02:50 hours. The circadian variation in the nuclear expression of cyclins-E (G1/S phase), -A (G2-phase), and -B1 (M-phase) with a normal physiological progression over time suggests a statistically significant circadian variation in oral epithelial cell proliferation. The finding of a circadian variation in the nuclear expression of p53 protein corresponding to late G1 is novel. This information has clinical implications regarding the timing of chemotherapy and radiotherapy.  (+info)

The biological clock of very premature primate infants is responsive to light. (5/9125)

Each year more than 250,000 infants in the United States are exposed to artificial lighting in hospital nurseries with little consideration given to environmental lighting cycles. Essential in determining whether environmental lighting cycles need to be considered in hospital nurseries is identifying when the infant's endogenous circadian clock becomes responsive to light. Using a non-human primate model of the developing human, we examined when the circadian clock, located in the hypothalamic suprachiasmatic nuclei (SCN), becomes responsive to light. Preterm infant baboons of different ages were exposed to light (5,000 lux) at night, and then changes in SCN metabolic activity and gene expression were assessed. After exposure to bright light at night, robust increases in SCN metabolic activity and gene expression were seen at ages that were equivalent to human infants at 24 weeks after conception. These data provide direct evidence that the biological clock of very premature primate infants is responsive to light.  (+info)

Effects of different light intensities during the daytime on circadian rhythm of core temperature in humans. (6/9125)

The present study was to determine the effects of bright light exposure during the daytime on core temperature rhythm. Eight female students participated as subjects. They were exposed to bright light of 5000 lux or dim light of 200 lux for 13 hours (06:30-19:30) for two consecutive days. Except the sleep period (22:30-06:30) and during the bright light exposure, light intensity was controlled at 200 lux. Rectal temperature data were collected every 10 min throughout the whole experimental period. The mean level of rectal temperature was not significantly different between the bright and the dim light conditions. However, the evening fall and the morning rise of rectal temperature were significantly greater in the bright light conditions on Day 2 compared to the dim. Furthermore, cosinor analysis showed that the acrophase of rectal temperature rhythm was earlier on Day 2 in the bright light conditions than the dim, and was significantly delayed on Day 2 compared to Day 1 in the dim light conditions. These results suggest that low intensity during the daytime for two consecutive days may induce a phase delay of core temperature rhythm rather than the bright light exposure at least in normally entrained female subjects.  (+info)

Ambulatory blood pressure monitoring and progression in patients with IgA nephropathy. (7/9125)

BACKGROUND: Hypertension is a recognized marker of poor prognosis in IgA nephropathy. METHODS: The present study investigated the prevalence of white-coat hypertension, the diurnal rhythm of blood pressure (BP), the effectiveness of antihypertensive drug therapy, and the effect of the above on the progression of the kidney disease in IgA nephropathy. One hundred twenty-six IgA nephropathy patients were selected consecutively for 24-h ambulatory blood pressure monitoring (ABPM). Fifty-five patients were normotensive and 71 were treated hypertensives. Their antihypertensive drugs were angiotensin-converting enzyme inhibitors (ACEI) alone or in combination with calcium-channel blockers (CCB). RESULTS: The mean night-time BP of normotensives (108+/-9/67+/-6 mmHg) was significantly lower than their day-time BP (125+/-8/82+/-7 mmHg, P<0.05). There was no significant difference between the mean day-time and night-time BP in hypertensive patients (125+/-9/82+/-7 mmHg vs 128+/-10/85+/-9 mmHg). The circadian variation of BP was preserved ('dippers') in 82% of the normotensive and 7% of the hypertensive patients (P<0.001). There were 10 'white-coat hypertensives' among the patients classified as normotensives with ABPM (mean office blood pressure 149+/-7/96+/-8 mmHg, 24-h blood pressure 127+/-6/83+/-5 mmHg, P<0.05) and 14 among treated hypertensives (mean office BP 152+/-8/98+/-6 mmHg, 24-h BP 130+/-4/85+/-8 mmHg, P<0.05). There was no difference in mean day-time BP among normotensive and treated hypertensive patients (125+/-8/81+/-5 mmHg vs 128+/-10/85+/-9 mmHg). Hypertensives had significantly higher night-time BP (125+/-9/85+/-9 mmHg) than normotensives (108+/-9/67+/-6 mmHg, P<0.001). There was no difference in serum creatinine levels among the different groups at the time of the ABPM. However, thirty-six+/-4.1 months after the ABPM, hypertensive patients (n=52) had higher serum creatinine levels (124+/-32 micromol/l) than at the time of the ABPM (101+/-28 micromol/l). The serum creatinine of normotensive patients (n=43) did not change during the follow-up period. 'Non-dipper' normotensives (n=10) had significantly higher serum creatinine levels at the end of the follow-up period than at its beginning (106+/-17 micromol/l vs 89+/-18 micromol/l, P<0.05). There was no increase in serum creatinine of 'dipper' normotensives. The mean serum creatinine of 'white-coat hypertensives' was significantly higher at the end of the study period than at its beginning. CONCLUSIONS: There is no diurnal blood pressure variation in most of the hypertensive IgA nephropathy patients. ACEI and CCB treatment have better effect on day-time than night-time hypertension. The lack of the circadian rhythm and 'white-coat hypertension' seems to accelerate the progression of IgA nephropathy.  (+info)

Diurnal variation and age differences in the biochemical markers of bone turnover in horses. (8/9125)

Biochemical markers of bone turnover provide sensitive, rapid, and noninvasive monitoring of bone resorption and formation. Serum concentrations of osteocalcin (OC) reflect rates of bone formation, and urinary concentrations of the pyridinium crosslinks pyridinoline (Pyd) and deoxypyridinoline (Dpd) are specific and sensitive markers of bone resorption. These markers are age-dependent and are used to detect and monitor changes in the rates of bone turnover in a variety of orthopedic diseases in humans and may prove to have similar application in horses. This study examined age differences and diurnal variation in OC, Pyd, and Dpd in eight adult geldings and seven weanling colts. Blood and urine were collected at regular intervals over 24 h. Serum OC and cortisol, and urinary Pyd and Dpd were analyzed. Mean 24-h concentrations of cortisol and all three markers were higher (P<.003) in weanlings than adults. Significant 24-h variation was observed in adult gelding OC, Pyd, and Dpd concentrations (P< .02). Adult OC concentrations were highest between 2400 and 0900; Pyd and Dpd peaked between 0200 and 0800. Similar patterns of bone turnover were observed in weanling values, but they were not significant (P>.17) owing to greater variability between individuals. Cortisol secretion varied (P<.001) over 24 h in both adults and weanlings and, thus, did not seem to be responsible for greater variability in markers of bone turnover between weanlings. These data demonstrate that diurnal rhythms exist for serum OC and urinary Pyd and Dpd in adult horses, as reported in humans, and that sample timing is an important consideration in future equine studies using these markers.  (+info)

*Circadian rhythm

In medical science, an abnormal circadian rhythm in humans is known as circadian rhythm disorder. In 2017, the Nobel Prize in ... Health problems can result from a disturbance to the circadian rhythm. Circadian rhythms also play a part in the reticular ... the circadian rhythm continues to be disrupted. The stabilization of sleep and the circadian rhythm might possibly help to ... circadian rhythms in quail. What drove circadian rhythms to evolve has been an enigmatic question. Previous hypotheses ...

*Drosophila circadian rhythm

Biological rhythms are first and best studied from Drosophila. Drosophila circadian rhythm has paved the way for understanding ... Thus, the clock is reset to commence the next circadian cycle. Dubowy, Christine; Sehgal, Amita (2017). "Circadian Rhythms and ... This is because the circadian clocks are fundamentally similar. Drosophila circadian rhythm was discovered in 1935 by German ... there was no circadian rhythm; in one mutation (called perS, "S" for short or shortened) the rhythm was shortened by ~19 hours ...

*Bacterial circadian rhythm

Bacterial circadian rhythms, like other circadian rhythms, are endogenous "biological clocks" that have the following three ... have well-documented circadian rhythms that meet all the criteria of bona fide circadian rhythms. In these bacteria, three key ... The luminescence rhythms expressed by these transformed S. elongatus fulfilled all three key criteria of circadian rhythms: ... Lin R-F, and Huang, T-C (2009) Circadian rhythm of Cyanothece RF-1 (Synechococcus RF-1). Chapter 3 in: Bacterial Circadian ...

*Circadian rhythm sleep disorder

Humans, like most living organisms, have various biological rhythms. Circadian rhythms, often referred to as the body clock or ... "Altered or disrupted sensitivity to zeitgebers is probably the most common cause of circadian rhythm disorder." Circadian ... People with circadian rhythm sleep disorders are unable to go to sleep and awaken at the times commonly required for work and ... Circadian rhythm sleep disorders (CRSD) are a family of sleep disorders affecting (among other bodily processes) the timing of ...

*Light effects on circadian rhythm

Chronobiology Circadian advantage Circadian clock Circadian oscillator Circadian rhythm disorders Electronic media and sleep ... exposure to light soon after wakening advances the circadian rhythm, whereas exposure before sleeping delays the rhythm. An ... Disruption of circadian rhythm as a result of light also produces changes in metabolism. Although many researchers consider ... Melatonin plays a large role in effects of light on circadian rhythms. When an organism is exposed to a light stimulus, the ...

*Journal of Circadian Rhythms

The Journal of Circadian Rhythms is a peer-reviewed open access scientific journal covering circadian and nycthemeral (daily) ... rhythms in living organisms, including processes associated with photoperiodism and daily torpor. It was established in 2003 ...

*Michael Ashburner

Moses, K; Ashburner, M (1985). "Circadian rhythms. Period piece for Drosophila". Nature. 315 (6015): 98. doi:10.1038/315098a0. ...

*Modafinil

... is "available to crew to optimize performance while fatigued" and helps with the disruptions in circadian rhythms and ... Zee PC, Attarian H, Videnovic A (February 2013). "Circadian rhythm abnormalities". Continuum. 19 (1 Sleep Disorders): 132-47. ... "Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders. An American Academy of Sleep ...

*Pseudo-response regulator

Liu, Yi; Bell-Pedersen, Deborah (2017-04-27). "Circadian Rhythms in Neurospora crassa and Other Filamentous Fungi". Eukaryotic ... McClung, C. Robertson (2006-04-01). "Plant Circadian Rhythms". The Plant Cell. 18 (4): 792-803. doi:10.1105/tpc.106.040980. ... TOC1 (gene) CCA1 Circadian Clock Salomé, Patrice A.; McClung, C. Robertson. "The Arabidopsis thaliana Clock". Journal of ... Matsushika, Akinori (2000). "Circadian Waves of Expression of the APRR1/TOC1 Family of Pseudo-Response Regulators in ...

*Jet lag

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 ... Jet lag was previously classified as one of the circadian rhythm sleep disorders. The condition of jet lag may last several ... Most people have an endogenous circadian rhythm that is longer than 24 hours, so lengthening a day is less troublesome than ... It does not necessarily involve the shift in circadian rhythms that cause jet lag. Travel fatigue can occur without crossing ...

*Light therapy

Morning therapy has provided the best results because light in the early morning aids in regulating the circadian rhythm. A ... In the management of circadian rhythm disorders such as delayed sleep phase disorder (DSPD), the timing of light exposure is ... Zisapel, Nava (2001). "Circadian Rhythm Sleep Disorders". CNS Drugs. 15 (4): 311-328. doi:10.2165/00023210-200115040-00005. ... circadian rhythm disorders and skin conditions like psoriasis, other applications include the use of low level laser, red light ...

*Circaseptan

A circaseptan rhythm is a cycle consisting of 7 days in which many biological processes of life resolve. Circadian rhythm ... "Palaeochronobiology circadian rhythms, gauges of adaptive Darwinian evolution: about 7-day circaseptan rhythms, gauges of ... 1987: Circaseptan rhythm in sodium and potassium excretion in salt-sensitive and salt-resistant 'Dahl rats'". Progr Clin Biol ... 755-762 Meyer-Rochow, VB; Brown, PJ (1998). "Possible natural circaseptan rhythm in the beach beetle Chaerodes trachyscelides ...

*Fetal movement

Fetuses aged 14 to 18 weeks show a pronounced circadian rhythm in their activity level, which can be detected both by fetal ... J Circadian Rhythms. 3 (1): 5. doi:10.1186/1740-3391-3-5. PMC 1079927 . PMID 15801976. Vaughan, Christopher (1996). How Life ...

*Sleep

Circadian rhythm exerts some influence on the nighttime secretion of growth hormone. The circadian rhythm influences the ideal ... "Introduction to Sleep and Circadian Rhythms", in Turek & Zee (eds.), Regulation of Sleep and Circadian Rhythms, pp. 1-17. Derk- ... "Cellular and Molecular Mechanisms of Circadian Rhythms in Mammals", in Turek & Zee (eds.), Regulation of Sleep and Circadian ... "Functional Genomics of Sleep and Circadian Rhythm Invited Review: Integration of human sleep-wake regulation and circadian ...

*Biology of depression

Depression may be related to abnormalities in the circadian rhythm, or biological clock. For example, rapid eye movement (REM) ... Germain, Anne; Kupfer, David J. (6 December 2016). "CIRCADIAN RHYTHM DISTURBANCES IN DEPRESSION". Human psychopharmacology. 23 ... inflammation and the circadian rhythm. Genetic factors involved in depression have been difficult to identify. In 2003 Science ...

*Visual impairment

"Circadian Rhythm Sleep Disorder" (PDF). American Academy of Sleep Medicine. 2008. Archived from the original (PDF) on 2010-08- ... Sack RL, Lewy AJ, Blood ML, Keith LD, Nakagawa H (July 1992). "Circadian rhythm abnormalities in totally blind people: ... a condition in which a person's circadian rhythm, normally slightly longer than 24 hours, is not entrained (synchronized) to ...

*Accelerating dark adaptation in humans

Link, Roberts, J. E. (2010). Circadian rhythm and human health. Link Archived March 26, 2015, at the Wayback Machine., Federal ...

*Adam K & Soha

"Adam K + Soha* - Circadian Rhythm". Discogs. Retrieved 2016-06-17. "Adam K & Soha Wiki, biography, pictures, Adam K & Soha ... "Adam K, Soha New Releases: Circadian Rhythm on Beatport". www.beatport.com. Retrieved 2016-06-22. "Adam K, Soha New Releases: ... "Circadian Rhythm". Their music has received tens of millions of plays and streams together with great support from Tiesto, ... "Adam K, Soha New Releases: I Like Rhythm on Beatport". www.beatport.com. Retrieved 2016-06-22. "Adam K, Soha New Releases: Come ...

*Myocardial infarction

Shaw E, Tofler GH (July 2009). "Circadian rhythm and cardiovascular disease". Current atherosclerosis reports. 11 (4): 289-95. ... The size and location puts a person at risk of abnormal heart rhythms (arrhythmias) or heart block, aneurysm of the heart ... However, 1 in 200 people were prevented from a repeat heart attack, and another 1 in 200 from having an abnormal heart rhythm. ... Disturbances of heart rhythms, including atrial fibrillation, ventricular tachycardia and fibrillation and heart block can ...

*Sleep medicine

Chronic circadian rhythm disorders, the most common of which is delayed sleep phase disorder, may be managed by specifically- ... A further subdivision of the dyssomnias preserves the integrity of circadian rhythm sleep disorders, as was mandated by about ... Polysomnography is not routinely used in the evaluation of patients with insomnia or circadian rhythm disorders, except as ... Chronotherapy has also been prescribed for circadian rhythm disorders, though results are generally short-lived. Stimulants may ...

*Roberto Refinetti

Refinetti is best known as the author of Circadian Physiology, a comprehensive book on circadian rhythms (first edition: 1999; ... Refinetti, R; Lissen, G. C.; Halberg, F (2007). "Procedures for numerical analysis of circadian rhythms". Biological Rhythm ... He is the editor-in-chief of the Journal of Circadian Rhythms and of the journal Sexuality & Culture, as well as section editor ... Refinetti, R (2004). "Non-stationary time series and the robustness of circadian rhythms". Journal of Theoretical Biology. 227 ...

*Delayed sleep phase disorder

Dagan Y (2002). "Circadian rhythm sleep disorders (CRSD)" (PDF). Sleep Med Rev. 6 (1): 45-54. doi:10.1053/smrv.2001.0190. PMID ... Patients with circadian rhythm sleep disorders often have difficulty maintaining ordinary social lives, and some of them lose ... Taken this late, it does not, of itself, affect circadian rhythms, but a decrease in exposure to light in the evening is ... 2007). "Circadian rhythm sleep disorders: part II, advanced sleep phase disorder, delayed sleep phase disorder, free-running ...

*Peroxiredoxin

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 ... 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 ...

*KaiB

... model of circadian rhythmicity. Circadian rhythms - endogenous, entrainable oscillations in biological processes with periods ... Ultimately, these circadian rhythms in KaiC phosphorylation governed by KaiA and KaiB binding create a post-translation ... Chen, T.-H.; Chen, T.-L.; Hung, L.-M.; Huang, T.-C. (1991). "Circadian Rhythm in Amino Acid Uptake by Synechococcus RF-1". ... 37 (2): 173-7. doi:10.1111/j.1574-6968.1986.tb01788.x. Huang, T.-C.; Tu, J.; Chow, T.-J.; Chen, T.-H. (1990). "Circadian Rhythm ...

*Eye

"Circadian Rhythms Fact Sheet". National Institute of General Medical Sciences. Retrieved 3 June 2015. Breitmeyer, Bruno (2010 ... which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells ... send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment and to the ...

*Childbirth

Reiter, R. J.; Tan, D. X.; Korkmaz, A.; Rosales-Corral, S. A. (2013). "Melatonin and stable circadian rhythms optimize maternal ...
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
To screen for output signals that may distinguish the pacemaker in the mammalian suprachiasmatic nucleus (SCN) from peripheral-type oscillators in which the canonical clockworks are similarly regulated in a circadian manner, the rhythmic behavior of the transcriptome in forskolin-stimulated NIH/3T3 fibroblasts was analyzed and compared relative to SCN2.2 cells in vitro and the rat SCN. Similar to the circadian profiling of the SCN2.2 and rat SCN transcriptomes, NIH/3T3 fibroblasts exhibited circadian fluctuations in the expression of the core clock genes, Per2, Cry1, and Bmal1, and 323 functionally diverse transcripts, many of which regulate cellular communication. Overlap in rhythmic transcripts among NIH/3T3 fibroblasts, SCN2.2 cells, and the rat SCN was limited to these clock genes and four other genes that mediate fatty acid and lipid metabolism or function as nuclear factors. Compared with NIH/3T3 cells, circadian gene expression in SCN oscillators was more prevalent among genes mediating ...
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 systems represent an endogenous mechanism adapted to cycling environmental conditions. In mammals, the central circadian clock is located in the suprachiasmatic nuclei (SCN), guiding circadian-regulated biological variables such as the sleep-wake cycle, hormonal secretions and locomotor activity [1]. Another physiological process that exhibits circadian fluctuations, with obvious implications in disease progression and outcome, is the regulation of immune function.. The link between the circadian and the immune systems has been extensively investigated [2-4]. Circadian rhythms within the immune system were described in several tissues and cellular populations [5]. In humans, the number of lymphocytes and granulocytes peaks during the night, whereas monocytes and neutrophil levels fall during the day [6]. Major humoral immune responses undergo circadian changes, and rhythms in plasmatic levels of pro-inflammatory cytokines, as well as peptide hormones produced and secreted by immune ...
Circadian phase resetting in older people by ocular bright light exposure.. Aging is associated with frequent complaints about earlier bedtimes and waketimes. These changes in sleep timing are associated with an earlier timing of multiple endogenous rhythms, including core body temperature (CBT) and plasma melatonin, driven by the circadian pacemaker. One possible cause of the age-related shift of endogenous circadian rhythms and the timing of sleep relative to clock time is a change in the phase-shifting capacity of the circadian pacemaker in response to the environmental light-dark cycle, the principal synchronizer of the human circadian system. METHODS: We studied the response of the circadian system of 24 older men and women and 23 young men to scheduled exposure to ocular bright light stimuli. Light stimuli were 5 hours in duration, administered for 3 consecutive days at an illuminance of approximately 10,000 lux. Light stimuli were scheduled 1.5 or 3.5 hours after the CBT nadir to induce ...
In the context of bacterial circadian rhythms, specifically in cyanobacteria, circadian advantage refers to the improved survival of strains of cyanobacteria that "resonate" with the environmental circadian rhythm. [6] For example, consider a strain with a free-running period (FRP) of 24 hours is co-cultured with a strain that has a free-running period (FRP) of 30 hours in a light-dark cycle of 12 hours light and 12 hours dark (LD 12:12). The strain that has a 24 hour FRP will out-compete the 30 hour strain over time. An instance where bacterial circadian rhythms are theorized to provide an advantage is in the microbiome. It is possible that circadian clocks play a role in the gut microbiota behavior. These microorganisms experience daily changes associated with daily LD and temperature cycles through an alteration of their environment. This occurs through behaviors such as eating rhythms on a daily routine (consumption in the day for diurnal animals and in the night for nocturnal). The presence ...
Sleep and circadian rhythm disruption (SCRD) and schizophrenia are often co-morbid. Here, we propose that the co-morbidity of these disorders stems from the involvement of common brain mechanisms. We summarise recent clinical evidence that supports this hypothesis, including the observation that the treatment of SCRD leads to improvements in both the sleep quality and psychiatric symptoms of schizophrenia patients. Moreover, many SCRD-associated pathologies, such as impaired cognitive performance, are routinely observed in schizophrenia. We suggest that these associations can be explored at a mechanistic level by using animal models. Specifically, we predict that SCRD should be observed in schizophrenia-relevant mouse models. There is a rapidly accumulating body of evidence which supports this prediction, as summarised in this review. In light of these emerging data, we highlight other models which warrant investigation, and address the potential challenges associated with modelling schizophrenia and
All domains of life feature diverse molecular clock machineries that synchronize physiological processes to diurnal environmental fluctuations. However, no mechanisms are known to cross-regulate prokaryotic and eukaryotic circadian rhythms in multikingdom ecosystems. Here, we show that the intestinal microbiota, in both mice and humans, exhibits diurnal oscillations that are influenced by feeding rhythms, leading to time-specific compositional and functional profiles over the course of a day. Ablation of host molecular clock components or induction of jet lag leads to aberrant microbiota diurnal fluctuations and dysbiosis, driven by impaired feeding rhythmicity. Consequently, jet-lag-induced dysbiosis in both mice and humans promotes glucose intolerance and obesity that are transferrable to germ-free mice upon fecal transplantation. Together, these findings provide evidence of coordinated metaorganism diurnal rhythmicity and offer a microbiome-dependent mechanism for common metabolic ...
Background AMP protein kinase (AMPK) plays an important role in food intake and energy metabolism, which are synchronized to the light-dark cycle. In vitro, AMPK affects the circadian rhythm by regulating at least two clock components, CKIα and CRY1, via direct phosphorylation. However, it is not known whether the catalytic activity of AMPK actually regulates circadian rhythm in vivo. Methodology/Principal Finding The catalytic subunit of AMPK has two isoforms: α1 and α2. We investigate the circadian rhythm of behavior, physiology and gene expression in AMPKα1−/− and AMPKα2−/− mice. We found that both α1−/− and α2−/− mice are able to maintain a circadian rhythm of activity in dark-dark (DD) cycle, but α1−/− mice have a shorter circadian period whereas α2−/− mice showed a tendency toward a slightly longer circadian period. Furthermore, the circadian rhythm of body temperature was dampened in α1−/− mice, but not in α2−/− mice. The circadian pattern of core
Epicardial fat tissue is known to have an unique endocrine function which affect the cardiac autonomic system. Heart rate recovery (HRR) is a simple non-invasive measurement that assesses autonomic nervous system dysfunction. We aimed to investigate the association among epicardial fat thickness (EFT), HRR and circadian blood pressure (BP) variation in patients with hypertension. A total of 358 consecutive patients who underwent both 24-hour ambulatory BP monitoring (ABPM) and a treadmill test were enrolled. Echocardiographic EFT and HRR, defined as peak heart rate minus heart rate after a 1-min recovery time, were measured. Patients were classified according to the ABPM; 147 patients with hypertension with a dipping pattern at night (dippers), 140 patients with hypertension with a non-dipping pattern at night (non-dippers) and 71 normotensive controls. EFT was significantly higher in hypertensive patients, especially in the non-dipper group, compared to the controls (non-dippers, 7.5 ± 2.9 mm; dippers
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 ...
The adrenal cortex has a molecular clock that generates circadian rhythms in glucocorticoid production, yet it is unclear how the clock responds to acute stress. We hypothesized that stress-induced ACTH provides a signal that phase shifts the adrenal clock. To assess whether acute stress phase shifts the adrenal clock in vivo in a phase-dependent manner, mPER2::LUC mice on a 12:12h light:dark cycle underwent restraint stress for 15 min or no stress at zeitgeber time (ZT) 2 (early subjective day) or at ZT16 (early subjective night). Adrenal explants from mice stressed at ZT2 showed mPER2::LUC rhythms that were phase-advanced by ~2h, whereas adrenals from mice stressed at ZT16 showed rhythms that were phase-delayed by ~2h. The biphasic response also was observed in mice injected subcutaneously either with saline or with ACTH at ZT2 or ZT16. Blockade of the ACTH response with the glucocorticoid, dexamethasone, prevented restraint stress-induced phase shifts in the mPER2::LUC rhythm both at ZT2 and at ZT16.
Circadian rhythms in physiology and behavior are observed in almost all phyla. Genetically encoded internal clocks generate such rhythms. Identification of gene products required for the generation and maintenance of endogenous circadian near 24-hr rhythms has led to a paradigm of multiple interlocked transcriptional/translational feedback loops as the basis for molecular circadian oscillators in all studied model systems. Protein phosphorylation plays an essential role, regulating the stability, activity and subcellular localization of proteins that constitute the biological clock. This study investigates the role of the protein kinase Doubletime, a Drosophila ortholog of casein kinase Is, in the fruit fly circadian clock. For the first time enzymatically active Doubletime protein is produced and direct phosphorylation of clock protein Period is demonstrated. Phosphorylation sites are identified and their functional significance is tested in a cell culture system. An in vivo analysis of a Period mutant
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 effects of aging on thyroxine and cortisol responses to low ambient temperatures and on circadian rhythm of cortisol in the ...
Circadian rhythms allow organisms to anticipate and prepare for precise and regular environmental changes. They thus enable organisms to better capitalize on environmental resources (e.g. light and food) compared to those that cannot predict such availability. It has therefore been suggested that circadian rhythms put organisms at a selective advantage in evolutionary terms. However, rhythmicity appears to be as important in regulating and coordinating internal metabolic processes, as in coordinating with the environment.[18] This is suggested by the maintenance (heritability) of circadian rhythms in fruit flies after several hundred generations in constant laboratory conditions,[19] as well as in creatures in constant darkness in the wild, and by the experimental elimination of behavioral, but not physiological, circadian rhythms in quail.[20][21]. What drove circadian rhythms to evolve has been an enigmatic question. Previous hypotheses emphasized that photosensitive proteins and circadian ...
Sleep and circadian rhythm disruption has been widely observed in neuropsychiatric disorders including schizophrenia [1] and often precedes related symptoms [2] . However, mechanistic basis for this association remains unknown. Therefore, we investigated the circadian phenotype of blind-drunk (Bdr), a mouse model of synaptosomal-associated protein (Snap)-25 exocytotic disruption that displays schizophrenic endophenotypes modulated by prenatal factors and reversible by antipsychotic treatment [3, 4]. Notably, SNAP-25 has been implicated in schizophrenia from genetic [5-8] , pathological [9-13], and functional studies [14-16] . We show here that the rest and activity rhythms of Bdr mice are phase advanced and fragmented under a light/dark cycle, reminiscent of the disturbed sleep patterns observed in schizophrenia. Retinal inputs appear normal in mutants, and clock gene rhythms within the suprachiasmatic nucleus (SCN) are normally phased both in vitro and in vivo. However, the 24 hr rhythms of arginine
Circadian rhythms, the biological oscillations based around our 24-hour clock, have a profound effect on human physiology and healthy cellular function. Circadian Rhythms: Health and Disease is a wide-ranging foundational text that provides students and researchers with valuable information on the molecular and genetic underpinnings of circadian rhythms and looks at the impacts of disruption in our biological clocks in health and disease.. Circadian Rhythms opens with chapters that lay the fundamental groundwork on circadian rhythm biology. Section II looks at the impact of circadian rhythms on major organ systems. Section III then turns its focus to the central nervous system. The book then closes with a look at the role of biological rhythms in aging and neurodegeneration.. Written in an accessible and informative style, Circadian Rhythms: Health and Disease,will be an invaluable resource and entry point into this fascinating interdisciplinary field that brings together aspects of ...
Nearly all organisms living near the surface of the Earth contain circadian (circa - "about"; diem- "day") clocks functioning as an endogenous timekeeping mechanism by which the organism can coordinate biological processes with 24h cycles in the external environment (such as the daily light:dark cycle). In nature, the ~24h free-running oscillation of circadian clocks is synchronized or entrained with the precisely 24h solar day cycle. In mammals, the master circadian pacemaker is located in the hypothalamic suprachiasmatic nucleus (SCN) which regulates ~24h rhythms of biological activity. The master circadian pacemaker within the SCN modulates adrenal gland release of glucocorticoids (GCs). GCs are a class of steroids critical for the mobilization of energy throughout the organism. GCs are released from the adrenal cortex and exhibit a circadian oscillation anticipating the onset of locomotor activity. In addition to humoral input to the adrenal cortex via adrenocorticotropic hormone (ACTH), the ...
Circadian rhythms, the subset of endogenous rhythms with a period of approximately 24 h, are widely encountered in most organisms from cyanobacteria to humans. Although eukaryotes employ a common mechanistic logic of interlocked negative feedback loops to generate robust circadian oscillations, different components have been recruited to form the clock in different taxa (Bell-Pedersen et al., 2005; McClung, 2006; Wijnen and Young, 2006). Thus, fungal, animal, and plant clocks share a common architectural plan yet are composed of largely distinct components. This suggestion of polyphyletic origins of clocks implies strong selection for clock function. Indeed, in many organisms, including cyanobacteria, fruit fly, ground squirrel, and Arabidopsis (Arabidopsis thaliana), experimental evidence indicates that a robust circadian clock whose period resonates with the environmentally imposed diurnal cycle confers a fitness advantage (Yerushalmi and Green, 2009).. Among plants, most that is known about ...
Circadian rhythms, the subset of endogenous rhythms with a period of approximately 24 h, are widely encountered in most organisms from cyanobacteria to humans. Although eukaryotes employ a common mechanistic logic of interlocked negative feedback loops to generate robust circadian oscillations, different components have been recruited to form the clock in different taxa (Bell-Pedersen et al., 2005; McClung, 2006; Wijnen and Young, 2006). Thus, fungal, animal, and plant clocks share a common architectural plan yet are composed of largely distinct components. This suggestion of polyphyletic origins of clocks implies strong selection for clock function. Indeed, in many organisms, including cyanobacteria, fruit fly, ground squirrel, and Arabidopsis (Arabidopsis thaliana), experimental evidence indicates that a robust circadian clock whose period resonates with the environmentally imposed diurnal cycle confers a fitness advantage (Yerushalmi and Green, 2009).. Among plants, most that is known about ...
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 ...
Hazlerigg, DG, Ebling, FJP and Johnston, JD (2005) Photoperiod differentially regulates gene expression rhythms in the rostral and caudal SCN ...
Purpose : Changes in eye growth that lead to myopia or hyperopia are associated with alterations in the circadian rhythms in eye length and choroidal thickness in animal models. Recent studies have shown that light at night has deleterious effects on human health via "circadian disruptions" in various physiological rhythms. The purpose of this study was to determine the effects of 2-hour episodes of light at night on the rhythms in axial length and choroidal thickness, and on growth rate and refraction in the chick model. Methods : At 2 weeks of age, birds received light (700 lux) between 12:00 am and 2:00 am for 7 days (n=18; total light=14 hr). Age-matched controls had a continuous dark night (n=22; 14L/10D). Ocular dimensions were measured using high-frequency A-scan ultrasonography on the first day, and again on day 7 at 6-hr intervals for 24 hr, starting at noon. Measurements during the night used a photographic safe-light. These data were used to determine rhythm parameters of phase and ...
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 ...
In Arabidopsis thaliana, a number of circadian-associated factors have been identified, including TOC1 (TIMING OF CAB EXPRESSION 1) that is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9). As demonstrated previously, these APRR1/TOC1 quintet members are crucial for a better understanding of the molecular links between circadian rhythms, control of flowering time through photoperiodic pathways, and also photosensory signal transduction in this dicotyledonous plant. In this respect, both the dicotyledonous (e.g. A. thaliana) and monocotyledonous (e.g. Oryza sativa) plants might share the evolutionarily conserved molecular mechanism underlying the circadian rhythm. Based on such an assumption, and as the main objective of this study, we asked the question of whether rice also has a set of pseudo-response regulators, and if so, whether or not they ...
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 ...
This is the first study to show that RICTOR/mTORC2 acts as a regulator for coordinated diurnal expression of clock genes in PVAT, but not in the SCN. At the whole body level, RICTOR/mTORC2 in adipose and brain tissue contributes to the diurnal regulation of blood pressure and locomotor activity. The presented data demonstrate the importance of the mTORC2 signaling pathway in the brain to adipocyte axis for daily fluctuations of physiological processes.. We and others have recently shown that mTORC2 activity controls inflammatory molecule expression using tissue-specific Rictor knockout mouse models.7,20 We showed that vascular contractility in RictoraP2KO mice is increased because of enhanced secretion of proinflammatory cytokines in PVAT.7 Ablation of Rictor strongly reduced AKTSer473 phosphorylation, resulting in impaired mTORC2 signaling.5-7 Consequently, we assign the observed changes in RictoraP2KO mice to the impaired mTORC2 downstream signaling.. In this study, we explored these findings ...
Circadian entrainment is a fundamental property by which the period of the internal biological clock is entrained by recurring exogenous signals, such that the organisms endocrine and behavioral rhythms are synchronized to environmental cues. In mammals, a master clock is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and may synchronize circadian oscillators in peripheral tissues. Light signal is the dominant synchronizer for master SCN clock. Downstream from the retina, glutamate and PACAP are released and trigger the activation of signal transduction cascades, including CamKII and nNOS activity, cAMP- and cGMP-dependent protein kinases, and mitogen-activated protein kinase (MAPK). Of non-photic entrainment, important phase shifting capabilities have been found for melatonin, which inhibits light-induced phase shifts through inhibition of adenylate cyclase (AC). Multiple entrainment pathways converge into CREB regulation. In turn, phosphorylated CREB activates clock gene ...
In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus constitutes the central circadian pacemaker. The SCN receives light signals from the retina and controls peripheral circadian clocks (located in the cortex, the pineal gland, the liver, the kidney, the heart, etc.). This hierarchical organization of the circadian system ensures the proper timing of physiological processes. In each SCN neuron, interconnected transcriptional and translational feedback loops enable the circadian expression of the clock genes. Although all the neurons have the same genotype, the oscillations of individual cells are highly heterogeneous in dispersed cell culture: many cells present damped oscillations and the period of the oscillations varies from cell to cell. In addition, the neurotransmitters that ensure the intercellular coupling, and thereby the synchronization of the cellular rhythms, differ between the two main regions of the SCN. In this work, a mathematical model that accounts for this heterogeneous
Disruption of two genes that control circadian rhythms can lead to diabetes, a researcher at UT Southwestern Medical Center has found in an animal study.. Mice with defective copies of the genes, called CLOCK and BMAL1, develop abnormalities in pancreatic cells that eventually render the cells unable to release sufficient amounts of insulin.. "These results indicate that disruption of the daily clock may contribute to diabetes by impairing the pancreas ability to deliver insulin," said Dr. Joseph Takahashi, an investigator with the Howard Hughes Medical Institute at UT Southwestern and co-senior author of the study, which appeared in the journal Nature. Dr. Takahashi, who recently joined UT Southwestern as chairman of neuroscience, performed the research with colleagues when he was at Northwestern University.. Circadian rhythms are cyclical patterns in biological activities, such as sleeping, eating, body temperature and hormone production.. The mammalian CLOCK gene, which Dr. Takahashi ...
Introduction. World Literature Essay II: C Candidate Number: 000 119 023 Word Count:1071 Total Number of Pages: 4 The Individual vs. The Party in Darkness at Noon by Arthur Koestler Purpose Statement: The fundamental believes of the Party explained by Arthur Koestler were oppressive to the ideological believes of the individual. In return the revolution failed to reach a utopian society due to the oppression of the individual. The party describe in Darkness at Noon by Arthur Koestler represents the governmental and economic system of communism in the Soviet Union during the 1930s and 40s with the main intend of reaching a utopia in the real world. The sacrifice of the individual was necessary to carry out the will of history in the eyes of the party. The ideology of the party creates a conflict in Darkness at Noon where the ideologies of the party undermined the ideas of the grammatical fiction with a result of a failed revolution. An individual perception is needed to help the rest of ...
The present study demonstrated that under strictly controlled dietary conditions plasma levels of Hcy shows significant daily rhythmicity, which is independent of the 24-h cycle of sleep and wake, with a peak at around 2200 to 2400. Previously, similar rhythmicity in Hcy with an evening peak was reported in obese diabetic patients by Bremner et al [12] and with nocturnal peak in rats by Baydas et al [13]. We further extended these findings by demonstrating that daily rhythms exist also in normal young adults. In contrast to Hcy, there was no daily rhythmicity in methionine, leucine, isoleucine and tyrosine, in which the 24-h pattern followed both the timing of sleep and the feeding schedule.. Homocysteine is a non-protein sulfur containing amino acid, and an intermediate in the metabolism of the essential amino acid methionine. The metabolism of Hcy is accomplished by two major pathways, remethylation into methionine and transsulfuration to cystationine [14]. In remethylation, Hcy acquires a ...
This study provides critical evidence in support of the hypothesis that activation of NMDA receptors is a sufficient and necessary step in the transduction of photic information to the circadian clock located in the SCN. Previous research had demonstrated that microinjection of either NMDA antagonists or non-NMDA antagonists into the SCN region could block the phase-shifting effects of light (Colwell and Menaker, 1992) and that application of glutamate to the hypothalamic slice preparation could phase shift the SCN neuronal firing rhythm in a pattern similar to that produced by light pulses in vivo(Ding et al., 1994). Recently, we demonstrated that microinjection of NMDA into the SCN region was capable of producing both phase delays and phase advances of the circadian locomotor activity rhythm (Mintz and Albers, 1997). This paper extends that finding to demonstrate that direct application of NMDA to the SCN in vivo produces a light-like phase-response curve, that this effect is specific to NMDA ...
Organisms face unforeseen short- and long-term changes in the environment (stressors). To defend against these changes, organisms have developed a stress system that includes the hypothalamic-pituitary-adrenal (HPA) axis, which employs glucocorticoids and the glucocorticoid receptor (GR) for signal transduction. In addition, organisms live under the strong influence of day-night cycles and, hence, have also developed a highly conserved circadian clock system for adjusting their activities to recurring environmental changes. This regulatory system creates and maintains internal circadian rhythmicity by employing a self-oscillating molecular pacemaker composed of the Clock-Bmal1 heterodimer and other transcription factors. The circadian clock consists of a central master clock in the suprachiasmatic nucleus of the brain hypothalamus and peripheral slave clocks in virtually all organs and tissues. The HPA axis and the circadian clock system communicate with each other at multiple levels. The ...
Altered natural rhythms Although circadian rhythms are endogenous to every living organism on earth they are largely influenced by natural daylight. Thus in space, where the normal rhythm of daylight/night cycling no longer exists, these circadian rhythms are perturbed. This has an impa…
Video articles in JoVE about circadian rhythm include In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells, Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila, Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures, Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents, Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters, The FlyBar: Administering Alcohol to Flies, Blue-hazard-free Candlelight OLED, Assaying Locomotor Activity to Study Circadian Rhythms and Sleep Parameters in Drosophila, Slice Preparation, Organotypic Tissue Culturing and Luciferase Recording of Clock Gene Activity in the Suprachiasmatic Nucleus, Measuring Circadian and Acute Light Responses in Mice using Wheel Running Activity, Analysis of Circadian Photoresponses in Drosophila Using Locomotor
Study Design and Patient Selection. Our main hypothesis is that elevated circulating levels of tumor-associated cytokines could significantly alter the QOL of cancer patients through the production of circadian clock dysfunction.. A prospectively studied population of 200 consecutive metastatic colorectal cancer patients referred for systemic chronochemotherapy at Paul-Brousse Hospital, Villejuif, France served as the index population as previously reported (5). Before receiving chronochemotherapy, these patients had rest/activity monitoring with wrist actigraphy and serum cortisol rhythm assessment as part of their initial work up. The analysis of the rest/activity records allowed the ranking of the patients according to r24, a robust index of the circadian rhythmicity in activity (see below). From these 200 patients, 80 were selected based upon r24 ranking. Forty patients in the top quartile displayed near normal circadian rhythm (group I) and 40 other patients in the lowest quartile had ...
Sleep-wake patterns observed by a circadian rhythm disruption protocol. White bar: light cycle, Black bar: dark cycle, Gray bar: dark cycle during disruption ph
Biological rhythms are driven by circadian oscillators, which are ultimately controlled by the cyclic expression of clock genes. Cryptochromes (CRY), blue light photoreceptors, belong to the negative elements of the transcriptional feedback loop into the molecular clock. This paper describes the cloning and characterization of two cryptochromes (cry1 and 2) in European seabass, which is considered an interesting chronobiology model due to its dual (diurnal/nocturnal) behavior. The cloned cDNA fragments encoded for two proteins of 567 and 668 amino acids, which included the FAD-binding and the DNA-photolyase domains. Moreover, both proteins had a high homology with cryptochrome proteins (Cry) of other teleost fish. These cry1 and 2 genes were expressed in several tissues of seabass (brain, liver, heart, retina, muscle, spleen, gill and intestine). In addition, the daily expression of cry1 was rhythmic in brain, heart and liver with the acrophase around ZT 03:15 h (after the onset of lights). ...
Circadian rhythms in health and disease. We investigate cellular mechanisms underlying circadian rhythmicity and how these can be altered in diseases and conditions that are characterized by sleep and rhythm dysfunctions.. Human physiology and behavior undergo daily (circadian = 24 hr) rhythms that are generated by an internal "body clock", the hypothalamic suprachiasmatic nuclei (SCN). Rhythms may become disturbed by internal or external factors, for instance in "jet lag", which occurs after rapid traveling across time zones. Disturbed rhythms are also common in certain psychiatric disorders, neurodegenerative diseases and aging. Deciphering all components in the circadian machinery is a prerequisite for developing new therapeutic strategies to treat circadian rhythm disorders, and to bridge circadian research to the clinics.. Circa 24-h rhythmicity is generated by molecular feedback loops of rhythmically expressed genes and their protein products. Recent studies suggest that also neuronal ...
LA JOLLA, CA-Scientists have known for some time that throwing off the bodys circadian rhythm can negatively affect body chemistry. In fact, workers whose sleep-wake cycles are disrupted by night shifts are more susceptible to chronic inflammatory diseases such as diabetes, obesity and cancer.. Researchers at the Salk Institute for Biological Studies have now found a possible molecular link between circadian rhythm disturbances and an increased inflammatory response. In a study published July 9 in Proceedings of the National Academy of Sciences, the Salk team found that the absence of a key circadian clock component called cryptochrome (CRY) leads to the activation of a signaling system that elevates levels of inflammatory molecules in the body.. "There is compelling evidence that low-grade, constant inflammation could be the underlying cause of chronic diseases such as diabetes, obesity and cancer," says senior author Inder Verma, a professor in Salks Laboratory of Genetics and the Irwin and ...
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
In this reflection, perhaps we can consider but one line in the Gospel which both challenges our love, and is a sign of Gods humble and abiding love for us: For there was no room for them in the Inn.. I. The Cold - There is a knock at midnight. Joseph, speaking on behalf of both Mary and Jesus (who is in her womb still), seeks entrance to the homes and lodgings of those in Bethlehem. And even though the Jewish people placed a great deal of emphasis on the duty of hospitality to strangers, the answer repeatedly given is that there is "No room here." Marys obviously advanced pregnancy seems to make little difference.. This was indeed a cold night, not so much in terms of the air temperature, but in terms of the hearts of the people. Even at the local inn (and surely someone could make room for a pregnant woman!), there was "No room.". Yes, it was a cold night! The only warmth would be found among the animals of that town. An old Latin antiphon for Christmas says, O magnum mysterium et admirabile ...
... What Are Circadian Rhythms? Circadian rhythms influence our body temperature, sleep and wakefulness, and various hormonal changes.
Circadian clocks regulate daily patterns of behavior, metabolism, and immune system function. At the core of the clock are transcriptional and translational feedback loops that generate periodic, oscillating changes in the abundance of clock components. One of these loops involves the action of the transcription factors CLOCK and BMAL1, heterodimers of which stimulate the expression of genes encoding the transcription factors Period 1 and Period 2 (PER1 and PER2). PER1 and PER2 accumulate in the cytoplasm, translocate into the nucleus, and inhibit transcription of Clock and Bmal1. The timing of transcription and translation of clock components is important for determining the clocks periodicity, and Chen et al. report that microRNAs (miRNAs) play a key role in this timing mechanism. Because the circadian clock is essential for early development, the authors used mice harboring a conditional knockout of Dicer, which encodes a critical component of the miRNA processing machinery, to assess the ...
The human body functions according to a circadian rhythm thought to be controlled by a biological clock located in the part of the brain called the hypothalamus. There are several distinct disorders of our circadian rhythm and these are listed below: ...
In collaboration with Hajime Tei, Ph.D., who successfully cloned a mammalian homologue of the Drosophila period gene, we developed a rodent model for monitoring real-time circadian gene expression rhythm by bioluminescence.. Using this technique, we discovered circadian clocks in mammalian peripheral organs. As a result, we view the mammalian circadian system as a multi-oscillator system, rather than a system controlled by one pacemaker structure in the SCN.. The discovery also allows biochemical analysis to be performed in abundant tissues such as the liver, which accelerated understanding of the molecular mechanisms of timekeeping. We realized that out-of-sync relationships among clocks in peripheral organs contribute to many human diseases. Every tissues internal circadian rhythm delicately controls the local physiology of that tissue; even small changes in that timing can result in malaise, such as metabolic syndrome and obesity.. ...
A biological clock exists in many organisms and controls rhythmic behaviors such as the activity pattern of locomotion. At the cellular level, it has been shown that circadian rhythms in the morphology of neurons exist in the fruit fly Drosophila melanogaster. The studies presented in this thesis contribute to an increased understanding of this novel aspect of neuronal plasticity and its regulation.. We demonstrated the existence of a circadian rhythm in the morphology of neuromuscular terminals that innervate two identified flight muscles. Synaptic boutons are larger during the day than during the night under light:dark conditions (LD) as well as in constant darkness (DD). However, this rhythm is abolished in normal flies older than 30 days and in arrhythmic ones with null mutations in the clock genes period (per) or timeless (tim). Furthermore, these clock mutants show a completely different branching pattern indicating that the proteins PER and TIM not only function in well-described ...
To test the circadian rhythm of fruit flies, Sehgal and others exposed wild type (control) and mutant flies to several light and dark settings constant darkness, constant light, and equal periods of light and darkness (a light-dark cycle). During exposure to constant light for one week, the controls developed a disrupted sleep pattern after a few days, while the mutants maintained a regular circadian rhythm. The mutant and control flies displayed no behavioral differences during their exposure to constant darkness and the light-dark cycle. However, when the fruit flies were shifted from one light-dark cycle to another, the mutant flies took two days longer to adjust their sleep-wake cycle to the new light-dark schedule ...
To test the circadian rhythm of fruit flies, Sehgal and others exposed wild type (control) and mutant flies to several light and dark settings constant darkness, constant light, and equal periods of light and darkness (a light-dark cycle). During exposure to constant light for one week, the controls developed a disrupted sleep pattern after a few days, while the mutants maintained a regular circadian rhythm. The mutant and control flies displayed no behavioral differences during their exposure to constant darkness and the light-dark cycle. However, when the fruit flies were shifted from one light-dark cycle to another, the mutant flies took two days longer to adjust their sleep-wake cycle to the new light-dark schedule ...
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 ...
Circadian rhythms are mechanisms that measure time on a scale of about 24 h and that adjusts our body to external environmental signals. Core circadian clock genes are defined as genes whose protein products are necessary components for the generation and regulation of circadian rhythms. Circadian proteins also regulate genes involved in either cell division or death; and a perturbation of the balance among these processes leads to cancer development and progression.. A key aspect of cancer research is identifying new regulatory pathways involved in proliferation and differentiation of cell. Disruption of circadian rhythm has recently emerged as a new potential risk factor in the development of cancer, pointing to the core gene period 2 (per2) as a tumor suppressor. However, it remains unclear how the circadian network regulates tumor suppression, nor which, if any, of its components is either the ultimate effector that influences the fate of the cell.. Initial experiments were devoted to ...
Pittsburgh-atonians, take note! Friday July 18th, at midnight (so, technically Saturday the 19th, but you know what I mean - wake up Friday, do your thing, then go see the movie at midnight), Saturday July 19th at midnight, and Sunday July 20th at 10PM, The Oaks Theater will be showing Ghostbusters as part of their 6th Annual Moonlight Matinees. Thanks to Eric for the tip. For more information on the showings, check here.. ...
Transcriptional repressor 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
A circadian rhythm /sɜːrˈkeɪdiən/ is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in plants, animals, fungi, and cyanobacteria.[1]
View Notes - Quiz_7 from BIOL 1002 at LSU. Title: Quiz 7 Assign To: BIOL 1002 - 004 Name: DeRoche, Lauren M Due Date: 04/13/2008 Note: Due Date is at midnight. Questions Hormones only stimulate
Come To Me At Midnight: An Erotic Ghost Story - Kindle edition by Narcissa Kyle. Download it once and read it on your Kindle device, PC, phones or...
Circadian rhythms are affected too. Circadian rhythms are natural metabolic rhythms that occur in virtually all higher organisms. They too are driven by the biological clock so that the organism can anticipate the coming of dawn and dusk and modify its metabolism to be ready for the new conditions. Many metabolic functions are controlled in this way. These include the rhythmic production of melatonin (a sleep hormone) and the diversion of metabolic resources from physical activity during the day, to repair and the immune system at night.. Consequences of losing the circadian rhythm. If the rhythm were to be lost or become weaker due to a failure of the clock as a result of electromagnetic exposure, it would have serious consequences. In humans it would result in tiredness during the day, poor sleep at night, and a reduced nightly production of the sleep hormone melatonin. All of these effects have been reported in people exposed to the radiation from cell towers and other sources of continuous ...
AbeBooks.com: The Bay at Midnight (9781494518783) by Diane Chamberlain and a great selection of similar New, Used and Collectible Books available now at great prices.
Painted by Charles White, the Late Afternoon wall mural from Murals Your Way will add a distinctive touch to any room. Choose a pre-set size, or customize to your wall.
Purpose: Sirtuins are a family of NAD-dependent deacetylase that are involved in a variety of cellular functions including metabolism, DNA repair, apoptosis, neuronal survival and inflammation. However, much of the sirtuins in the retina are largely unknown. In this study, we analyzed the mRNA levels of seven sirtuins (Sirt1-7) together with the sirtuin-associated molecules, and the effect of light-dark condition on the expression levels in the retina.. Methods: Six-week-old male C57BL6/J mice were used. The mice were kept under 12-h light/12-h dark (LD) cycle. After keeping under the usual LD cycle for 2 weeks, the mice were randomly divided into the LD group and constant darkness group (DD group). The DD group was transferred to constant darkness after the dark phase of the last LD cycle, and kept in the dark for two 24-hours DD cycles, and then, sacrificed during third 24-hours DD cycle. The retina and the liver of the LD and DD group mice were sampled every 4 hours, and brain parietal ...
TY - JOUR. T1 - Haematopoietic stem cell release is regulated by circadian oscillations. AU - Méndez-Ferrer, Simón. AU - Lucas, Daniel. AU - Battista, Michela. AU - Frenette, Paul S.. PY - 2008/3/27. Y1 - 2008/3/27. N2 - Haematopoietic stem cells (HSCs) circulate in the bloodstream under steady-state conditions, but the mechanisms controlling their physiological trafficking are unknown. Here we show that circulating HSCs and their progenitors exhibit robust circadian fluctuations, peaking 5 h after the initiation of light and reaching a nadir 5 h after darkness. Circadian oscillations are markedly altered when mice are subjected to continuous light or to a jet lag (defined as a shift of 12 h). Circulating HSCs and their progenitors fluctuate in antiphase with the expression of the chemokine CXCL12 in the bone marrow microenvironment. The cyclical release of HSCs and expression of Cxcl12 are regulated by core genes of the molecular clock through circadian noradrenaline secretion by the ...
Circadian rhythms maintain an organisms daily sleep-wake cycle by conserved regulatory pathways, inducing profound effects in metabolic activity. Drosophila circadian period is maintained in a 24-hour cycle with peaks of activity at dawn and dusk. Ethanol exposure causes disruptions in a variety of physiological processes including circadian rhythms. We hypothesized that defects in circadian rhythm might lead to altered behavioral responses to ethanol and to disruptions in ethanol metabolism. To investigate this hypothesis, we used Drosophila strains bearing mutations in the period gene that result in circadian periods which are longer (perL) or shorter (perS) compared to wild type rhythms. We analyzed ethanol metabolism by measuring alcohol dehydrogenase (Adh) activity, an enzyme that converts alcohol to aldehyde, and characterized behavioral responses to ethanol exposure by measuring sedation time, recovery from sedation, and tolerance after repeated exposure. This study will contribute to the
Exercise has many well-established benefits to physical and mental health (25-30). The intensity, duration, frequency, mode, volume, and progression of exercise to optimize the beneficial effects have been well characterized (26, 44, 45). However, the proper timing of exercise and its potential added benefit of improving circadian entrainment have not been investigated thoroughly. Disruption of circadian rhythms (e.g., by shift work, social jetlag, early-morning schedules) is associated with metabolic disorders, cardiovascular disease, and cancer (6-11). If exercise could reduce circadian disruption, then it may also improve the risk factors associated with this disruption.. A tenet of the mammalian circadian system is that it is differentially sensitive to stimuli given at different times of day. Therefore, it is likely that the response of the internal circadian rhythm to exercise depends on the time of day of exercise. We chose morning and evening exercise for 2 reasons. First, morning ...
Dawn phenomenon is the phenomenon which causes a rapid rise or fall in body blood sugar during early morning hours. Dawn phenomenon of diabetes walk common experience seen among diabetics as a result of insulin resisting hormones induced at night time. Lets go deep into the cause of this dawn phenomenon or liver dump effect. Researchers found that the cause of rise and fall in blood glucose level during early morning hours is mainly due to the release of insulin resisting hormones from liver.. Do you know what all are the hormones responsible for causing dawn phenomenon? Cortisol produced from adrenal cortex, glucagons released from alpha cells in pituitary gland, epinephrine formed from outer layer of adrenal glands and growth hormones are some examples of insulin resisting hormones causing dawn phenomenon or high blood sugar in early morning. Release of these hormones during sleep time hours initiates the release of stored energy there by increasing the level of blood glucose level.. As we ...
If these strategies do not work, poor vitamin A status should be considered a possible explanation. This interpretation is strengthened if you have poor night vision (for example, if you strain your eyes or have trouble seeing when driving down an unlit road with your headlights alone but can see fine without any eyestrain during the day) or dry eyes. This interpretation is also strengthened if you have serum retinol near or below the bottom of the reference range, or if you track your vitamin A intake and your daily average is below the RDA.. It is important to note that any of these additional pieces of evidence strengthen the interpretation of poor vitamin A status, but their absence does not rule it out. If circadian rhythm disruption is more sensitive to deficiency than night blindness, then it may occur in the absence of other clinical signs, at serum retinol concentrations within the reference range, and at vitamin A intakes above the RDA.. The best way to ensure basic adequacy of vitamin ...
Free-running sleep is a sleep pattern that is not adjusted (entrained) to the 24-hour cycle in nature nor to any artificial cycle. It occurs as the sleep disorder non-24-hour sleep-wake disorder or artificially as part of experiments used in the study of circadian and other rhythms in biology. Study subjects are shielded from all time cues, often by a constant light protocol, by a constant dark protocol or by the use of light/dark conditions to which the organism cannot entrain such as the ultrashort protocol of one hour dark and two hours light. Also, limited amounts of food may be made available at short intervals so as to avoid entrainment to mealtimes. Subjects are thus forced to live by their internal circadian "clocks". The individuals or animals circadian phase can be known only by the monitoring of some kind of output of the circadian system, the internal "body clock". The researcher can precisely determine, for example, the daily cycles of gene-activity, body temperature, blood ...
Blood pressure drugs should be taken at night.. Uncontrolled blood pressure can lead to heart attacks, paralysis and heart failure. Most such attacks occur in the early morning hours. Pulse, blood pressure and thickening of platelets are all higher in the early morning hours.. Controlling early morning blood pressure can reduce cardiovascular mortality.. According to a study published in the Journal of the American Society of Nephrology, among patients with chronic kidney disease and high blood pressure, taking at least one antihypertensive drug at bedtime significantly improves blood pressure control, with an associated decrease in risk for cardiovascular events.. The study included 661 patients with chronic kidney disease who were randomly assigned either to take all prescribed anti BP drugs on awakening or to take at least one of them at bedtime. Patients were followed for a median of 5.4 years; during that time, patients who took at least one BP-lowering drug at bedtime had approximately one ...
Physically active young adults (M = 14; F = 21) and older adults (M = 12; F = 21) were observed over a period of four to five days following a 90-minute "ultra-short" sleep-wake cycle (30-min sleep, 60-min wake). Baseline circadian rhythm was assessed over 30 hours. During the following three days, Ss were exposed to experimental phase-shifting treatments (randomly assigned exercise or bright light), centered at one of eight randomly assigned times around the 24-hour day. Treatments were one hour of treadmill exercise at 60-70% VO2peak, and three hours of bright light.. It was found that exercise had a similar influence on circadian rhythms as did bright light.. Implication. Regular exercise affects the circadian rhythm.. Return to Table of Contents for this issue.. ...
Keep in mind that the cortisol circadian rhythm described above is the same rhythm experienced by virtually every healthy human being on the planet. This is not true for those who suffer from most forms of exhaustion - including adrenal fatigue. The difficulty for most doctors who try to diagnose adrenal issues, however, is easy to understand: though the patterns in the rhythms are different, the differences between the typical levels of cortisol in a healthy and fatigued individual are not so obvious.. What is usually seen when cortisol is measured over the course of a day is that normal, healthy individuals have cortisol levels that tend to fall within a certain set range at any given point in that twenty-four hour cycle. The average person will usually have cortisol levels that fall somewhere near the middle of that normal range, between the high and low levels at any given moment.. Often times, when doctors measure an adrenal fatigue sufferers cortisol levels, those levels will fall within ...
Eur J Pharmacol. 2009 Mar 15;606(1-3):61-71. doi: 10.1016/j.ejphar.2009.01.029. Epub 2009 Jan 29. Research Support, Non-U.S. Govt
The detrimental effects of myocardial infarction in humans and rodents have a 24-h rhythm. In some human cohorts however, rhythmicity was absent, while the time of maximum damage differs between cohorts. We hypothesized that the type of damage influences the 24-h rhythm in infarct size. Myocardial infarction was induced in ... read more 12-week-old C57BL/six mice at four different time-points during the day using either permanent ligation (PL) or 30-min of ischemia followed by reperfusion (IR), with a control group wherein no ligation was applied. Infarct size was measured by echocardiography and histology at a 1-month follow-up. Rhythmicity in infarct size was present in the PL group at the functional and histological level, with maximal damage occurring when the infarct was induced at noon. In the IR group, no circadian rhythm was found. The time of the coronary artery ligation determines the outcome of myocardial infarction. Our data showed that in rodents, the presence of circadian ...
How genes control animal behavior is the big question my lab is interested in. We mainly study circadian (~24hr) rhythms of behavior, arguably the best understood behavior at molecular and cellular levels. We use the fruitfly Drosophila as a powerful model system that has led the way in circadian rhythm research and is ideal for analyzing behavior at the level of single genes, single neurons, neuronal networks and whole animal behavior. We use Genetics, Genomics & BioInformatics, Microscopy and Behavioral assays to build a holistic model of how flies anticipate daily environmental changes.. Adult flies have 24hr rhythms in their activity: they are more active by day, especially at dusk and dawn, and rest by night - paralleling human sleep/wake cycles. These rhythms persist in constant darkness, indicating that flies have an internal sense of time. Forward genetics helped identify a set of core clock genes that are essential for 24hr rhythms in constant darkness, and these genes work together in ...
A circadian rhythm is a 24-hour period affecting the physiology of all living creatures, including plants and animals. While some circadian rhythm functions are governed internally, others are...
Humans, like almost all animals, are phase-locked to the diurnal cycle. Most of us sleep at night and are active through the day. Because we have evolved to function with this cycle, the circadian rhythm is deeply ingrained and even detectable at the biochemical level. However, within the broader day-night pattern, there are individual differences: e.g., some of us are intrinsically morning-active, while others prefer evenings. In this article, we look at digital daily cycles: circadian patterns of activity viewed through the lens of auto-recorded data of communication and online activity. We begin at the aggregate level, discuss earlier results, and illustrate differences between population-level daily rhythms in different media. Then we move on to the individual level, and show that there is a strong individual-level variation beyond averages: individuals typically have their distinctive daily pattern that persists in time. We conclude by discussing the driving forces behind these signature daily
Inherent in all living organisms, natures circadian rhythm springs us into activity in the daytime and then into rest and restoration at night. And this circadian rhythm is attuned to the presence and absence of the sun, principally blue light.. Melatonin is critical to regulating the bodys circadian rhythm. When the sun goes down and it becomes dark, our eyes sense the absence of light and send a signal to the brain, which instructs the pineal gland to produce melatonin and put us to sleep.. Now in modern times, the incandescent light began humankinds earliest assault on natures circadian rhythm. This has only worsened with the advent of television, computers, tablets, cell phones, gaming stations and whatever else produces light to interfere with our circadian rhythm. When the lights stay on, melatonin production is slowed or stopped.. Exposure to sunlight - at least 10 to 15 minutes a day is recommended - is also crucial to the production of vitamin D, which is found in very few foods but ...
Light, activity & meals are key inputs to the circadian rhythm. These tools can be used to help managing the circadian rhythm & getting it back in sync.
Kadener, S., J. S. Menet, K. Sugino, M. D. Horwich, U. Weissbein, P. Nawathean, V. V. Vagin, P. D. Zamore, S. B. Nelson, and M. Rosbash. 2009. A role for microRNAs in the drosophila circadian clock. Genes and Development 23, (18): 2179-219. Kadener, S., D. Stoleru, M. McDonald, P. Nawathean, and M. Rosbash. 2007. Clockwork orange is a transcriptional repressor and a new drosophila circadian pacemaker component. Genes and Development 21, (13): 1675-168. Rosbash, M. 2009. The implications of multiple circadian clock origins. PLoS Biology 7, (3): 0421-0425. Shang, Y., L. C. Griffith, and M. Rosbash. 2008. Light-arousal and circadian photoreception circuits intersect at the large PDF cells of the drosophila brain. Proceedings of the National Academy of Sciences of the United States of America 105, (50): 19587-19594. Stoleru, D., P. Nawathean, M. d. l. P. Fernández, J. S. Menet, M. F. Ceriani, and M. Rosbash. 2007. The drosophila circadian network is a seasonal timer. Cell 129, (1): 207-219. ...
Circadian rhythms are the daily biological and physiological processes that cycle with a period of about 24 hours. In recent years, the circadian field has progressed significantly from the discovery of many genes involved in the core circadian function. The first mammalian circadian gene that was cloned, Clock, was shown to be a transcription factor that is critical for the proper functioning of the circadian system in mammals. Many studies have been conducted with the Clock Δ19 mutation and how ubiquitous perturbations in Clock gene function affect the circadian system at both the behavioral and molecular levels. However, the tissue specific role of the Clock gene in controlling circadian rhythms has not been addressed. In addition, circadian studies have not been conducted with a mouse model that contains a loss of expression of the Clock gene. In this study, we have attempted to address these two issues using a variety of different methods. First, we utilized the tetracycline transactivator ...
Another Midnight Run (1994) is the first in a series of made-for-TV movies for Universal Televisions Action Pack based on the popular feature film Midnight Run. Christopher McDonald takes over the role of bounty hunter Jack Walsh, originated in the first film by Robert De Niro. Another Midnight Run was followed by two more made-for-TV sequels, Midnight Runaround and Midnight Run for Your Life. Jack Walsh (McDonald) is hired by bail bondsman Eddie Moscone (Dan Hedaya) to bring in Bernie Abbot (Jeffrey Tambor) and Helen Bishop (Cathy Moriarty), a husband and wife team of con artists. Moscone also brings in rival bounty hunter Marvin Dorfler (Ed ORoss) to work with Jack, with the agreement that they will split the money; however, both men are planning to double cross each other. Christopher McDonald: Jack Walsh Jeffrey Tambor: Bernie Abbot Cathy Moriarty: Helen Bishop Ed ORoss: Marvin Dorfler John Fleck: Jerry Geisler Dan Hedaya: Eddie Moscone Sam Shamshak: Lester Weems Midnight Run 2: Another ...
Organisms and even single cells have endogenous biological "clocks" that allow them to tell the time of day. Research in our laboratory is directed towards understanding the cellular and molecular bases of these fascinating timing mechanisms in a variety of organisms: cyanobacteria ("blue-green algae"), plants, and animals. To analyze the molecular nature of the clock in the prokaryotic cyanobacteria, we have developed a bioluminescent reporter strain that expresses a daily rhythm of light emission. Using this bioluminescence rhythm as a marker, clock mutants have been identified. We found that the essential clock gene, KaiC, is rhythmically expressed and forms ATP-dependent hexamers. In collaboration with the laboratory of Dr. Martin Egli, we have crystallized KaiC to determine its three-dimensional structure and discover its phosphorylation sites. The three key bacterial clock proteins (KaiA + KaiB + KaiC) will show circadian oscillations in a test tube! In collaboration with the laboratories ...
In the camel, it has also been demonstrated that the daily Ta cycle is able to entrain the master circadian clock, thus highlighting that Ta is a true zeitgeber (El Allali et al. 2013). The protocol validated in this study will also permit to test in these specific conditions, if the zeitgeber effect of Ta cycle with higher amplitude is able, as suggested by (El Allali et al. 2013), to counteract the zeitgeber effect of the light-dark cycle, a fundamental question in mammalian circadian biology. It will also lead to determine more precisely the functioning of the master clock and the circadian network in dehydrated and heat‐stressed camels.. The use of data loggers over a long period of time has also facilitated understanding the interpretation of (Al‐Haidary 2005). In the present work, we observed that the increase in amplitude of Tb starts after 7 days under heat stress and water deprivation. In the work of (Al‐Haidary 2005), the analysis was only done after 4 days and the protocol used ...
by Vetscite. New research from Colorado State University shows that the function of all genes in mammals is based on circadian - or daily - rhythms. The study, refutes the current theory that only 10 percent to 15 percent of all genes were affected by natures clock. While scientists have long known that circadian rhythms regulate the behavior of the living, the study shows that daily rhythm dominates all life functions and particularly metabolism. The new study presents oscillation as a basic property of all genes in the organism as opposed to special function of some genes as previously believed. Knowing about oscillation properties of genes involved in metabolism is essential for understanding how genes interact with and regulate health and disease. Colorado State University researcher Andrey Ptitsyns new analysis of data collected through several studies establishes a baseline oscillation in 98 to 99 percent of all genes through advanced computer algorithms. Most of these genes have never ...
An in vivo screen of 86 RNAi lines, representing the majority of annotated Drosophila phosphatases/regulators, for altered activity rhythms was carried out. The screen identified a total of 19 candidate genes (Table 1) that altered clock function upon RNAi knockdown in Drosophila clock cells. Further genetic validation of one candidate showed that the RPTP Lar is required for the development of axonal projections from circadian pacemaker neurons that support rhythmic activity in constant darkness but not during light:dark cycles (Agrawal and Hardin 2016).. As expected, a majority of these candidates were not validated upon further analysis of independent genetic reagents (Table 2). However, these reagents consisted of additional P element inserts, where the P element insertion site may not interfere with gene function, or strains that could be used for overexpression, which also may not impact the function of a protein that is already at saturating levels. Therefore, a lack of validation with P ...
We experimentally demonstrated that the technique to stabilize the output signal by harmonic intensities is useful in heterodyne detection with an incoherent light source such as a halogen lamp. The relation between the relative standard deviation of an output signal and the fluctuation of the light intensity is analyzed and simulated. Using the fundamental to sixth harmonics increases the stabilities of output signal approximately 3 times, and subtracting the relative standard deviation of the intensity of light source enhances the stabilities 49 times. The fluctuating phase that is due to the fluctuating frequency and temperature and its power spectrum density for an interferometer is also calculated with the Allan variance.. © 2002 Optical Society of America. Full Article , PDF Article ...
Scientists have shown that disruption of the bodys internal clock system is involved in a range of diseases, from psychiatric to metabolic to cardiovascular. A recent paper by JDRF-funded researcher Joseph Bass, M.D., Ph.D., suggests that it could also be a factor in the development of diabetes. Dr. Bass and his group found that disruption of the circadian rhythm set by the bodys internal clock led to glucose intolerance in mice, raising the possibility that it might have similar effects in people.. The timing of most biological activities-like eating and sleeping-is coordinated with the daily light cycle by the bodys master circadian clock, located in the brain. The master clock communicates with a network of peripheral clocks distributed in tissues and organs throughout the body, including the pancreas. Dr. Basss group previously found that the clock within the pancreas has roles in releasing insulin and normalizing blood-glucose concentration, but the details of how it does this were not ...
EVANSTON, Ill. --- Eat less, exercise more. Now there is new evidence to support adding another "must" to the weight-loss mantra: eat at the right time of day. A Northwestern University study has found that eating at irregular times -- the equivalent of the middle of the night for humans, when the body wants to sleep -- influences weight gain. The regulation of energy by the bodys circadian rhythms may play a significant role. The study is the first causal evidence linking meal timing and increased weight gain.. "How or why a person gains weight is very complicated, but it clearly is not just calories in and calories out," said Fred Turek, professor of neurobiology and physiology in the Weinberg College of Arts and Sciences and director of the Center for Sleep and Circadian Biology. "We think some factors are under circadian control. Better timing of meals, which would require a change in behavior, could be a critical element in slowing the ever-increasing incidence of obesity.". The findings ...
Circadian clocks are found in nearly all organisms, from bacteria to mammals, and ensure that behavioral and physiological processes occur at optimal times of day and in the correct temporal order. It is becoming increasingly clear that chronic circadian misalignment (CCM), such as occurs in shift workers or as a result of aberrant sleeping and eating schedules common to modern society, has profound metabolic and cognitive consequences, but the proximate mechanisms connecting CCM with reduced organismal health are unknown. Furthermore, it has been difficult to disentangle whether the health effects are directly induced by misalignment or are secondary to the alterations in sleep and activity levels that commonly occur with CCM. Here, we investigated the consequences of CCM in the powerful model system of the fruit fly, Drosophila melanogaster. We subjected flies to daily 4-h phase delays in the light-dark schedule and used the Drosophila Activity Monitoring (DAM) system to continuously track locomotor
a_brandeis_university_study_published_this_week_in_nature_shows_for_the_first_time_that_a_molecular_signal_maintains_coherence_among_brain_clock_cells_that_regulate_daily_activity_of_drosophila_melanogaster_fruit_flies_the_two_key_groups_of_neurons_control_morning_and_evening_activity_and_are_maintained_in_synch_even_when_the_flies_are_plunged_into_darkness_for_extended_periods_of_time_
In article ,32FEBC37.7152 at umoncton.ca,, Rejean Hall, ing. ,hallr at umoncton.ca, wrote: , Hi everyone: , , My grade 5 daughter Micheline took up a class project to , answer that question. Any info, ref. or URL? , , Thanks , , R. Hall There is something like sleeping in plants, although you wouldnt call it that way. Plants undergo many daily variations, called rhythms. The leaf movement rhythms were the first described, but also photosynthetic activity etc. follow such a rhythm. In amy cases such an rhythm persists under constant condition which means if you transfer a plant from normal light dark cycles to constant conditions (constant dark or constant light) these rhythms will persist. To do so, they must be triggered by an internal mechanism, called the biological clock. You will find more information in a book called: RHYTHMIC PHENOMENA IN PLANTS, edited by B.M. Sweeney, Academic Press, San Diego/New York 1987. Hope that helps Thomas -- Thomas Urbig Email: Urbig at biosun.harvard.edu ...
We show under experimental conditions controlling for meal composition and physical activity that individuals with type 1 diabetes do not demonstrate a uniformly identifiable diurnal pattern of postprandial SI over meals that could be generalized to the disease population as a whole. This finding is contrary to our recent report in a similar cohort of healthy individuals (1) and could be the result of the greater variability of SI in type 1 diabetic individuals. However, the diurnal pattern of SI over meals notably showed differences between healthy and type 1 diabetic subject groups such that in the healthy subjects, SI fell from breakfast to lunch, whereas it rose from breakfast to lunch in the type 1 diabetic subjects.. Closed-loop control algorithms currently being developed for glucose control in type 1 diabetes need to be refined and optimized on the basis of multiple considerations, including physiological parameters and characteristics that relate to natural perturbations (e.g., meals, ...
China Supplier PVC H Profile New Production, Find details about China PVC H Profile, PVC Profile from China Supplier PVC H Profile New Production - QINGDAO YUJING FANYU TRADING CO., LTD.
Is This Increase in Early Morning Blood Pressure Bad?. Researchers have found that many types of life-threatening events, such as stroke and heart attack, happen more often during this early morning period. This may be due to rises in blood pressure and heart rate, and also to increases in certain hormones, such as angiotensin, renin, aldosterone, and adrenaline. These hormones tighten your blood vessels and make your heart work harder to pump blood to the body. If you have a buildup of gunkcalled plaques in your blood vessels that slows down blood, these stresses can lead to a stroke or heart attack.. A healthy lifestyle can often help people with high blood pressure. Also, scientists have developed certain high blood pressure and angina medications, which, when taken at bedtime, release higher amounts of drug in the early morning hours and lower amounts at night. These medications are known as chronotherapeutic.. What Do You Mean by Chronotherapeutic?. Coordinating biological rhythms ...
The first time I heard about the biological rhythms of a man was from a scientific adviser, Doctor of Psychology, Professor V. Klimenko. He described how, as a psychologist for the Soviet national chess team, he served the world champion Anatoly Karpov. It was then, according to him, the study of the basic biological rhythms of man was actively conducted. Professor Klimenko said there were even detective stories around the most successful dates for the three main biological rhythms of Karpov. Their team was trying to fix the date of the match, so they tried to set the date on these most successful dates for their athlete and on the most unfortunate dates for his opponent. And the opposing team, on the contrary, knowing and studying the same questions, tried to. counter these intentions and tried to win for themselves their most favorable days, and the unsuccessful days for the Soviet chess player. Professor Klimenko suggested that his calculations and conclusions, sometimes altered the fate of ...
An increasing number of studies have shown that circadian variation in the excretion of hormones, the sleep-wake cycle, the core body temperature, the tone of the autonomic nervous system and the activity rhythm are important both in health and disease processes. More attention is being paid towards the circadian variation in endogenous rhythms in relation to surgery and whether this can affect postoperative recovery, morbidity and mortality.. Studies have been done on circadian disturbances after major and minor surgery but never in relation to breast cancer surgery.. This study will investigate circadian disturbances in this specific group of patients by using Actigraphy, Polysomnography (PSG), Holter-monitoring (HRV), the primary metabolite of melatonin in urine 6-sulfatoxymelatonin (aMT6s), questionnaires and a sleep-diary. ...
The effects of circadian rhythms on human performance in general and on response to exercise in particular are a well-known phenomenon. Often after a poor nights sleep or taking a red-eye flight into a different time-zone, one just doesnt feel like themselves. This book aims to provide a comprehensive account of biological rhythms and how they affect exercise.
Since the dawn of life, most organisms have had to adapt to environmental cycles of light and darkness, and restrict many of their biological activities to specific times of day and night. Central to this adaptation is the evolution of an endogenous, self-sustained, 24 h (circadian) timekeeping mechanism (clock) that orchestrates body rhythms for concerted action and synchronizes (entrains) them to the local time of day [1]. In the last few decades, there have been spectacular advances in our understanding of this clock mechanism. It is a layered system with emergent properties at several levels of organization, including regulatory molecules, cells, circuits and tissues. It is believed that genes at the clocks core function as autoregulatory feedback loops within individual cells, with oscillating levels of nuclear proteins negatively regulating the transcription of their own mRNAs. Groups of autonomous single-cell oscillators are coupled together to form discrete pacemakers that generate ...
Circadian rhythms: Circadian rhythms are variations in physiology and behavior persisting with a cycle length close to, but not exactly, 24 hours. It is necessary to synchronize the rhythms on a regular basis to maintain them. And, such synchronization is usually achieved through regular exposure to light and darkness. Entrainment: Entrainment occurs when rhythmic physiological or behavioral events are matched to an external environmental factor. So it is ultimately the interaction between circadian rhythms and the environment, especially sunlight or darkness.. Homeostasis: The maintenance of metabolic equilibrium and balance within an animal by a tendency to compensate for disrupting changes. Thus, homeostasis is vital for good health. And conversely, a lack of homeostasis in the gut is a disease state. Microbiome, or microbiota: A collection of microorganisms living in or on the human body. For the purposes of this discussion, we are interested in those microorganisms, such as bacteria, ...
Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol), which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earths 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disorders. Therefore, first, we tested whether exposure to a model-based lighting regimen would entrain the human circadian pacemaker at a normal phase angle to the 24.65-h Martian sol and to the 23.5-h day length often required of astronauts during short duration space exploration. Second, we tested here whether such prior entrainment to non-24-h light-dark cycles would lead to subsequent modification of the intrinsic
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 ...
Chronobiology is the study of biological rhythms. It examines the effects of time on biological events and internal biological clocks. Over the past few decades, chronobiology has developed into a multidisciplinary field of interest in general medicine and psychiatry (1). Research on chronobiology is constantly growing and has contributed to the development of an interdisciplinary field of research. The Nobel Prize in Medicine in 2017 was awarded to scientists who investigated molecular mechanisms that control circadian rhythms.. The earths rotation and the daily light-dark or day-night cycle have had long and constant biological impacts on the earths living organisms. Over the long evolutionary process, organisms have developed clock-like structures. These biological clocks help organisms successfully perform their activities over a 24-h cycle. This adaptive ability predicts cyclic changes and allows behavioral and physiological harmonization. These endogenous clocks are useful because they ...
Find the best circadian rhythm sleep disorder doctors in New Delhi. Get guidance from medical experts to select circadian rhythm sleep disorder specialist in New Delhi from trusted hospitals - credihealth.com
Melatonin is a neurohormone secreted by the pineal gland and excreted by the urinary tract. It has a key role in the synchronisation of circadian rhythms including the sleep wake cycle, with a peak secretion around 03:00.. The neural pathway controlling melatonin secretion is long and transits via the thoracic spine. The exact level is not known, but interruption of the connection in patients with lesions of the spinal cord is known to occur.. Tetraplegic patients often complain of insomnia, daytime sleepiness and poor sleep quality but the contribution of melatonin levels to sleep quality has not been explored in large studies, although case reports have shown reduced or abolished melatonin secretion and altered melatonin secretion profiles with delayed peak secretion. Paraplegic patients report fewer sleep difficulties and little is known about melatonin secretion in this group. The investigators hypothesize that sleep abnormalities are related to abnormalities in melatonin secretion and that ...
It is important to reduce poststroke depression (PSD) to improve the stroke outcomes and quality of life in stroke patients, but the underlying mechanisms of PSD are not completely understood. As many studies implicate dysregulation of hypothalamic-pituitary-adrenal axis in the etiology of major depression and stroke, we compared the cortisol awakening response (CAR) of 28 admitted PSD patients with that of 23 age-matched caregiver controls. Saliva samples for cortisol measurement were collected immediately, 15, 30, and 45 min after awakening for two consecutive days. Depressive mood status in PSD patients was determined with Beck Depression Inventory and Hamilton Depression Rating Scale. Salivary cortisol levels of PSD patients did not rise significantly at any sampling time, showing a somewhat flat curve. Caregiver controls showed significantly higher CAR at 15 and 30 min after awakening compared to PSD patients even though the two groups did not differ at awakening or 45 min
Introduction. Hypertension is a primary risk factor for cardiovascular and cerebrovascular diseases, and renal failure. It is well known that the quantity of dietary salt intake plays a role in the pathogenesis of primary hypertension. Increased sensitivity of blood pressure to excess sodium affects 50% of patients with primary hypertension.1,2 Dietary salt intake causes an increase in blood pressure, and is associated with renal and cardiovascular diseases, including left ventricular hypertrophy and microalbuminuria.3-5 Spontaneous variation in blood pressure is referred to as blood pressure variability (BPV), and is classified as short-term BPV and long-term BPV.6,7 Fluctuation during a 24-h period is referred to as short-term BPV and is based on 24-h ambulatory blood pressure monitoring (ABPM). Variation between successive ABPM measurements is known as average real variability (ARV), which is mathematically calculated.8,9 BPV was reported to be associated with hypertension-related target ...
By Jennifer Copley (Last Updated 30 March 2012). Autistic spectrum disorders are often accompanied by a number of additional conditions, including difficulty sleeping, which afflicts up to 70% of autistic children (Andrew Zimmerman, MD, cited in Laino, 2009). Some studies have shown that children with autism tend to be deficient in melatonin, which is known as the "sleep hormone" because of the key role it plays in both circadian rhythms and seasonal rhythms (Laino, 2009; Melke et al., 2007; Rossignol, 2011).. How Melatonin Works. The pineal gland in the brain secretes melatonin to regulate circadian rhythms (sleep cycles). This gland produces more melatonin in darkness, and less in light, so bright lights at night or insufficient light during the day can have a negative impact on melatonin cycles. This is why working graveyard shifts, jet lag, and poor vision can all adversely affect melatonin. Melatonin also has antioxidant effects, so it may boost immune response. Studies have shown that ...
Pineal melatonin, an endogenous signal of darkness, is believed to be an important regulator of circadian and seasonal rhythms. The changing melatonin levels serve as hands of a bio-clock and dates of the biocalendar in vertebrates including humans. Circulating melatonin regulates and influences the sleep wake cycle, sexual development, as well as various immune, endocrine, and metabolic functions. Initially it was thought to be produced exclusively by pineal gland. Subsequently, it was shown that melatonin is also produced in several other tissues. Substantial amounts of melatonin are found in the gut as well as the brain. Moreover, melatonin is one of the most powerful scavengers of free radicals. Sleep disorders and low melatonin levels are frequently observed in people with autism spectrum disorders (ASD). The role of abnormal melatonin biosynthesis in the gastrointestinal system relating to the development of ASD symptoms warrants further studies. The important multiple role of melatonin in ...

Best Circadian Rhythm Sleep Disorder Doctor in New Delhi, Circadian Rhythm Sleep Disorder Doctors | CredihealthBest Circadian Rhythm Sleep Disorder Doctor in New Delhi, Circadian Rhythm Sleep Disorder Doctors | Credihealth

Get guidance from medical experts to select circadian rhythm sleep disorder specialist in New Delhi from trusted hospitals - ... Find the best circadian rhythm sleep disorder doctors in New Delhi. ... Best doctors for circadian-rhythm-sleep-disorder in New Delhi List of best Circadian Rhythm Sleep Disorder Doctors from trusted ... List of best Circadian Rhythm Sleep Disorder Doctors from trusted hospitals in New Delhi. Get detailed info on educational ...
more infohttps://www.credihealth.com/doctors/new-delhi/circadian-rhythm-sleep-disorder

Light therapyLight therapy

Intervention Bright light therapy is a common treatment for seasonal affective disorder and for circadian rhythm disorders. ICD ... Circadian rhythm sleep disorders. Chronic CRSD. In the management of circadian rhythm disorders such as delayed sleep phase ... Light therapy which strikes the retina of the eyes is used to treat circadian rhythm disorders such as delayed sleep phase ... Bright light therapy is a common treatment for seasonal affective disorder and for circadian rhythm disorders.. ...
more infohttps://en.academic.ru/dic.nsf/enwiki/368010/Light_therapy

Seasonal Affective Disorder (SAD)Seasonal Affective Disorder (SAD)

The bodys circadian rhythm (internal body clock). What are the symptoms of SAD? ...
more infohttps://warwick.ac.uk/services/counselling/informationpages/seasonalaffectivedisorder/

How to deal with seasonal affective disorderHow to deal with seasonal affective disorder

Fewer daylight hours during the winter can also upset this clock, also known as circadian rhythms. ... suggesting that this wavelength may powerfully affect circadian rhythms. Researchers are investigating whether blue light might ... reported that remission from SAD is twice as likely if this light therapy is also adjusted to your own melatonin rhythms. ...
more infohttp://www.sheknows.com/health-and-wellness/articles/1018801/how-to-deal-with-seasonal-affective-disorder

Seasonal Affective Disorder: Focus on the Winter BluesSeasonal Affective Disorder: Focus on the Winter Blues

... body temperature and cortisol rhythms, and the timing of sleep.3,4 It is theorized that circadian rhythms drift with the later ... The phase-shift hypothesis proposes that there is an optimal relationship between the timing of circadian rhythms, including ... The photoperiod hypothesis and phase-shift hypothesis are two theories based upon changes of the bodys circadian rhythms. ... As mentioned, SAD may be caused by phase-delayed circadian rhythms that, in turn, can initially cause insomnia. Counseling ...
more infohttps://www.uspharmacist.com/article/seasonal-affective-disorder-focus-on-the-winter-blues

SAD (Seasonal affective disorder (SAD)) - Diseases & ConditionsSAD (Seasonal affective disorder (SAD)) - Diseases & Conditions

Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may disrupt your bodys internal ... This disruption of your circadian rhythm may lead to feelings of depression. ...
more infohttp://pharmacypedia.org/diseases-and-conditions/sad-seasonal-affective-disorder-sad/

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...

The measurement of circadian rhythms has limitations. Some natural factors have masking effects on circadian rhythms. For ... Sleep episodes also affect circadian rhythms. Although the sleep-wake cycle is a major circadian rhythm and is controlled by ... which leads to a disruption in circadian rhythms (19).. Biological clock and circadian rhythms are useful if they can be ... and treatment of mood disorders show circadian rhythms. Similarly, their receptors are controlled by circadian rhythms (13,14 ...
more infohttp://balkanmedicaljournal.org/text.php?lang=en&id=1915

Seasonal Affective Disorder in Elders During Winter - AgingCare.comSeasonal Affective Disorder in Elders During Winter - AgingCare.com

A decline in the amount of daylight during fall and winter affects circadian rhythms and causes hormonal changes that lead to ...
more infohttps://www.agingcare.com/Articles/winter-seasonal-affective-disorder-depression-149072.htm

Seasonal Affective Disorder (S…Seasonal Affective Disorder (S…

2) Light therapy is also a good way to regulate your bodys circadian rhythm. Circadian rhythm is controlled by your body clock ... Melatonin is a hormone that is dictated by your circadian rhythm. Melatonin must be in balance. This is one prong to the fork ...
more infohttps://wittyjolt.wordpress.com/2016/09/19/seasonal-affective-disorder-sad-a-better-approach/comment-page-1/

Circadian Rhythms  - Lulu.comCircadian Rhythms - Lulu.com

Researchers have discovered that those with a disrupted circadian rhythm were unable to lose weight and keep it off no matter ... circadian rhythm of teams in the west traveling for a 10:00 am start, biggest win and loss from last season, odds to win ... circadian rhythms and mutation. The book closes with a fascinating look at the history and future trends for research on ... but rather of eating more frequently per day and irregular eating patterns which leads to a disrupted circadian rhythm. ...
more infohttp://www.lulu.com/shop/search.ep?keyWords=Circadian%20Rhythms

circadian rhythm | Journal of Neurosciencecircadian rhythm | Journal of Neuroscience

Cellular Location and Circadian Rhythm of Expression of the Biological Clock Gene Period 1 in the Mouse Retina Paul Witkovsky, ... Loss of Photic Entrainment and Altered Free-Running Circadian Rhythms in math5−/− Mice Raymond Wee, Ana Maria Castrucci, ... Circadian Phase-Dependent Modulation of cGMP-Gated Channels of Cone Photoreceptors by Dopamine and D2 Agonist Gladys Y.-P. Ko, ... Identification of a Circadian Clock in the Inferior Colliculus and Its Dysregulation by Noise Exposure Jung-sub Park, ...
more infohttp://www.jneurosci.org/keyword/circadian-rhythm

Aging Impacts Brains Circadian RhythmAging Impacts Brain's Circadian Rhythm

New research that involved the examination of thousands of genes from nearly 150 human brains shows the circadian rhythm of ... A 24-hour circadian rhythm controls nearly all brain and body processes, such as the sleep/wake cycle, metabolism, alertness ... The researchers next plan to explore the function of the brains circadian-rhythm genes in lab and animal models, as well as ... "We know also that the circadian rhythm changes with aging, leading to awakening earlier in the morning, fewer hours of sleep ...
more infohttps://psychcentral.com/news/2015/12/21/aging-impacts-brains-circadian-rhythm/96458.html

Module 2. Circadian Rhythms | NIOSH | CDCModule 2. Circadian Rhythms | NIOSH | CDC

Circadian Rhythms. Circadian rhythms are internally driven cycles of biochemical, physiological, and behavioral processes of ... throughout the human body that drive circadian rhythms. A master circadian pacemakera (sometimes called the circadian clock) in ... Circadian rhythms promote sleepiness before usual bedtime, help initiate sleep, and begin promoting wakefulness before usual ... As well as sleep and wakefulness, the pacemaker sets the timing for numerous circadian rhythms that regulate physiological and ...
more infohttps://www.cdc.gov/niosh/work-hour-training-for-nurses/longhours/mod2/13.html

Circadian Rhythms Promote Wakefulness | NIOSH | CDCCircadian Rhythms Promote Wakefulness | NIOSH | CDC

Circadian Rhythms Promote Wakefulness. Figure 3 shows the rise and fall of circadian rhythms for wakefulness. ... The rise and fall of circadian rhythms, which promote wakefulness across the 24-hour day. ...
more infohttps://www.cdc.gov/niosh/emres/longhourstraining/wakefulness.html

Circadian Rhythms | SpringerLinkCircadian Rhythms | SpringerLink

... those who are new to circadian biology, those who are already active in the field but are intereste ... The aim of Circadian Rhythms is to provide a resource that can be adopted by several types of users: ... The aim of Circadian Rhythms is to provide a resource that can be adopted by several types of users: those who are new to ... Use of Firefly Luciferase Activity Assays to Monitor Circadian Molecular Rhythms In Vivo and In Vitro ...
more infohttps://link.springer.com/book/10.1007%2F978-1-59745-257-1

Severe epilepsy and circadian rhythm protein linkedSevere epilepsy and circadian rhythm protein linked

New research shows that a protein involved in circadian rhythms, called CLOCK, plays a role in severe cases of epilepsy that do ... CLOCK is a key player in the regulation of our circadian rhythms. Mice with mutated versions of the gene are unable to maintain ... a protein involved in circadian rhythms, called CLOCK, may play a role.. New findings may open the door to novel epilepsy ... there was a decrease in the expression of mRNA coding for a protein called circadian locomotor output cycles kaput (CLOCK). ...
more infohttps://www.medicalnewstoday.com/articles/319718.php?iacp

Severe epilepsy and circadian rhythm protein linkedSevere epilepsy and circadian rhythm protein linked

New research shows that a protein involved in circadian rhythms, called CLOCK, plays a role in severe cases of epilepsy that do ... CLOCK is a key player in the regulation of our circadian rhythms. Mice with mutated versions of the gene are unable to maintain ... a protein involved in circadian rhythms, called CLOCK, may play a role.. New findings may open the door to novel epilepsy ... there was a decrease in the expression of mRNA coding for a protein called circadian locomotor output cycles kaput (CLOCK). ...
more infohttps://www.medicalnewstoday.com/articles/319718.php

Bacterial circadian rhythm - WikipediaBacterial circadian rhythm - Wikipedia

Bacterial circadian rhythm. (Redirected from Bacterial circadian rhythms). Bacterial circadian rhythms, like other circadian ... Circadian AdvantageEdit. In the context of bacterial circadian rhythms, specifically in cyanobacteria, circadian advantage ... have well-documented circadian rhythms that meet all the criteria of bona fide circadian rhythms. In these bacteria, three key ... Lin R-F, and Huang, T-C (2009) Circadian rhythm of Cyanothece RF-1 (Synechococcus RF-1). Chapter 3 in: Bacterial Circadian ...
more infohttps://en.m.wikipedia.org/wiki/Bacterial_circadian_rhythms

Melatonin: Correcting Circadian RhythmMelatonin: Correcting Circadian Rhythm

... Humans operate on a diurnal pattern and need sleep for brain development, physical and ... When most people hear the term circadian rhythm, they think about sleep cycles. Humans that operate on a diurnal pattern and ... Zisapel N. New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. Br J Pharmacol. ... The British Journal of Pharmacology has published a review article that deals with circadian rhythm and specifically with ...
more infohttps://www.pharmacytimes.com/resource-centers/vitamins-supplements/melatonin-correcting-circadian-rhythm

Circadian RhythmsCircadian Rhythms

Download a Free Excerpt from Circadian Rhythms:. Preface. Coordination between Differentially Regulated Circadian Clocks ... Circadian Rhythms. Book Series: A Cold Spring Harbor Perspectives in Biology Collection. Subject Area(s): Molecular Biology. ... In addition, the authors examine circadian rhythms in other species (e.g., plants and Drosophila) and how they enable the ... A 50-Year Personal Journey: Location, Gene Expression, and Circadian Rhythms. Michael Rosbash. Index. ...
more infohttps://cshlpress.com/default.tpl?action=full&cart=1550364466162468064&--eqskudatarq=1185&typ=ps%E2%89%A0wtitle=Circadian%20Rhythms

Circadian Rhythms
	Circadian Rhythms

Download a Free Excerpt from Circadian Rhythms:. Preface. Coordination between Differentially Regulated Circadian Clocks ... Circadian Rhythms. Book Series: A Cold Spring Harbor Perspectives in Biology Collection. Subject Area(s): Molecular Biology. ... In addition, the authors examine circadian rhythms in other species (e.g., plants and Drosophila) and how they enable the ... A 50-Year Personal Journey: Location, Gene Expression, and Circadian Rhythms. Michael Rosbash. Index. ...
more infohttps://cshlpress.com/default.tpl?action=full&cart=1550599944226747078&--eqskudatarq=1185&typ=ps&newtitle=Circadian%20Rhythms

Circadian Rhythms
	Circadian Rhythms

Download a Free Excerpt from Circadian Rhythms:. Preface. Coordination between Differentially Regulated Circadian Clocks ... Circadian Rhythms. Book Series: A Cold Spring Harbor Perspectives in Biology Collection. Subject Area(s): Molecular Biology. ... In addition, the authors examine circadian rhythms in other species (e.g., plants and Drosophila) and how they enable the ... A 50-Year Personal Journey: Location, Gene Expression, and Circadian Rhythms. Michael Rosbash. Index. ...
more infohttps://www.cshlpress.com/default.tpl?action=full&cart=1553191791711436702&--eqskudatarq=1185&typ=ps&newtitle=Circadian%20Rhythms

Circadian Rhythm of Genes Changes with AgeCircadian Rhythm of Genes Changes with Age

The circadian rhythm of gene activity changes with age, according to new study at the University of Pittsburgh School of ... Circadian Rhythm of Genes Changes with Age. By Traci Pedersen Associate News Editor ... The circadian rhythm of gene activity changes with age, according to new study at the University of Pittsburgh School of ... "We know also that the circadian rhythm changes with aging, leading to awakening earlier in the morning, fewer hours of sleep ...
more infohttps://psychcentral.com/news/2015/12/25/circadian-rhythm-of-genes-changes-with-age/96730.html

Circadian Rhythms - QIAGENCircadian Rhythms - QIAGEN

Circadian Rhythms RT2 Profiler PCR Array The Human Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Circadian Rhythms RT2 Profiler PCR Array The Mouse Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Circadian Rhythms RT2 Profiler PCR Array The Rat Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Although the circadian rhythm target genes vary widely from tissue to tissue, the transcription factors encoded by central ...
more infohttps://www.qiagen.com/se/shop/genes-and-pathways/complete-biology-list/circadian-rhythms/

Circadian Rhythms - QIAGENCircadian Rhythms - QIAGEN

Circadian Rhythms RT2 Profiler PCR Array The Human Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Circadian Rhythms RT2 Profiler PCR Array The Mouse Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Circadian Rhythms RT2 Profiler PCR Array The Rat Circadian Rhythms RT² Profiler PCR Array profiles the expression of 84 key ... Although the circadian rhythm target genes vary widely from tissue to tissue, the transcription factors encoded by central ...
more infohttps://www.qiagen.com/fi/shop/genes-and-pathways/complete-biology-list/circadian-rhythms/
  • Interacting positive and negative feedback loops at the transcriptional and post-translational level ensure tight control over transcription factors regulating expression of the appropriate genes required during circadian days or nights. (qiagen.com)
  • Genes regulated by circadian rhythms are involved in a diverse range of biological processes that affect physiology, metabolism, and behavior. (qiagen.com)
  • Dr. Panda's research focuses on the genes and cells that serve as the building blocks of the circadian rhythm. (iherb.com)
  • In perfect "clockwork" fashion, these genes continuously work together to release proteins that synchronize our biological rhythms with the time of day. (nfcr.org)
  • Some studies on the relationship between breast cancer and sleep disturbances from shift work point to hypermethylation of certain circadian genes and the shortening of telomeres-both associated risk factors for cancer. (nfcr.org)
  • The genetics was first understood in 1971, when Seymour Benzer and Ronald J. Konopka reported that mutation in specific genes changes or stops the circadian behaviour. (wikipedia.org)
  • But then other scientists were adamant, holding the notion that genes would not control such complex behaviours as circadian activities. (wikipedia.org)
  • The strongest evidence for cell-autonomous, circadian rhythm generation in mammals comes from transcriptional rhythms measured from primary and immortalized fibroblasts ( 3 , 4 ). (pnas.org)
  • His work is particularly focused on a portion of the brain known as the hypothalamus, which controls the circadian rhythm and utilizes several hormones to affect different parts of the body. (iherb.com)
  • We tested the hypothesis that circadian cycling is intrinsic to a unique class of SCN neurons by measuring firing rate or Period2 gene expression in single neurons. (pnas.org)
  • Here we demonstrate circadian rhythms in gene expression and firing rate from isolated SCN neurons and their subsequent identification by immunocytochemistry. (pnas.org)
  • The authors cover the physiology of diurnal rhythm thoroughly and discuss melatonin's emerging roles in diseases of aging. (pharmacytimes.com)
  • The earliest recorded account of a circadian process dates from the 4th century B.C.E., when Androsthenes, a ship captain serving under Alexander the Great, described diurnal leaf movements of the tamarind tree. (wikipedia.org)
  • Light stimuli were scheduled 1.5 or 3.5 hours after the CBT nadir to induce shifts of endogenous circadian pacemaker to an earlier hour (phase advances) or were scheduled 1.5 hours before the CBT nadir to induce shifts to a later hour (phase delays). (genomenewsnetwork.org)
  • The British Journal of Pharmacology has published a review article that deals with circadian rhythm and specifically with melatonin's role in metabolism and health. (pharmacytimes.com)
  • Differences in a person's circadian rhythm - such as any changes in light exposure, motor activity and temperature cycles - may help in the diagnosis and treatment of depressive mood disorders, according to new research conducted by the Chronobiology Laboratory in Porto Alegre, Brazil. (psychcentral.com)
  • METHODS: We studied the activity and core-body temperature rhythms in a cohort of 38 male patients with a clinical diagnosis of probable Alzheimer disease (AD) approximately 2 years before death. (genomenewsnetwork.org)
  • METHODS: We studied the response of the circadian system of 24 older men and women and 23 young men to scheduled exposure to ocular bright light stimuli. (genomenewsnetwork.org)
  • a Two small groups of nerve cells that lead numerous circadian rhythms. (cdc.gov)
  • Until the mid-1980s, it was thought that only eukaryotic cells had circadian rhythms. (wikipedia.org)
  • H2O2 might be functioning as a systemic signal by which rhythms are regulated within cells and between cells," said lead author John Tower, associate professor in molecular and computational biology at the USC College of Letters, Arts and Sciences. (thaindian.com)
  • We know a lot about how circadian rhythms are regulated within certain cells. (thaindian.com)
  • For the rhythms of even two cells to agree, some sort of signal has to pass between them. (thaindian.com)
  • 100 cells/mm 2 eliminated synaptic inputs and revealed circadian neurons that contained arginine vasopressin (AVP) or vasoactive intestinal polypeptide (VIP) or neither. (pnas.org)
  • Scientific research has found that increased weight gain is largely a result not of the number of calories consumed per meal, but rather of eating more frequently per day and irregular eating patterns which leads to a disrupted circadian rhythm. (lulu.com)
  • The existence of this circadian rhythm was independently discovered in D. melanogaster in 1935 by two German zoologists, Hans Kalmus at the Zoological Institute of the German University in Prague (now Charles University), and Erwin Bünning at the Botanical Institute of the University of Jena. (wikipedia.org)
  • They also looked into whether the rhythm differences could differentiate between healthy individuals and patients with acute and chronic depression. (psychcentral.com)
  • With regard to the rest/activity rhythm, women having their first depressive episode and those with chronic depression showed a decrease in amplitude (smaller time difference between the peak and crest of the cycle) compared with the control group. (psychcentral.com)
  • ALG Online's Health & Performance chapter describes the impact of light on human health-including implications for the circadian system-and outlines the ways in which lighting design can address those influences. (constantcontact.com)
  • Herein, "circadian" might be applied to all "24-hour" rhythms, whether or not their periods, individually or on the average, are diffeent from 24 hours, longer or shorter, by a few minutes or hours. (wikipedia.org)
  • Note: term describes rhythms with an about 24-h cycle length, whether they are frequency-synchronized with (acceptable) or are desynchronized or free-running from the local environmental time scale, with periods of slightly yet consistently different from 24-h. (wikipedia.org)