Biological Clocks: The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.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.CLOCK Proteins: Basic helix-loop-helix (bHLH) domain-containing proteins that contain intrinsic HISTONE ACETYLTRANSFERASE activity and play important roles in CIRCADIAN RHYTHM regulation. Clock proteins combine with Arntl proteins to form heterodimeric transcription factors that are specific for E-BOX ELEMENTS and stimulate the transcription of several E-box genes that are involved in cyclical regulation. This transcriptional activation also sets into motion a time-dependent feedback loop which in turn down-regulates the expression of clock proteins.Circadian 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.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.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.Caves: Geological formations consisting of underground enclosures with access from the surface.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.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.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.FlavoproteinsCircadian 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.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.Darkness: The absence of light.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.Periodicity: The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).Neurospora crassa: A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.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.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.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.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Aging: The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.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.Biological Products: Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.Copyright: It is a form of protection provided by law. In the United States this protection is granted to authors of original works of authorship, including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. (from Circular of the United States Copyright Office, 6/30/2008)Computer Security: Protective measures against unauthorized access to or interference with computer operating systems, telecommunications, or data structures, especially the modification, deletion, destruction, or release of data in computers. It includes methods of forestalling interference by computer viruses or so-called computer hackers aiming to compromise stored data.Confidentiality: The privacy of information and its protection against unauthorized disclosure.Privacy: The state of being free from intrusion or disturbance in one's private life or affairs. (Random House Unabridged Dictionary, 2d ed, 1993)Libraries: Collections of systematically acquired and organized information resources, and usually providing assistance to users. (ERIC Thesaurus, http://www.eric.ed.gov/ accessed 2/1/2008)Animal Husbandry: The science of breeding, feeding and care of domestic animals; includes housing and nutrition.Longevity: The normal length of time of an organism's life.Vitamins: Organic substances that are required in small amounts for maintenance and growth, but which cannot be manufactured by the human body.Vitamin A: Retinol and derivatives of retinol that play an essential role in metabolic functioning of the retina, the growth of and differentiation of epithelial tissue, the growth of bone, reproduction, and the immune response. Dietary vitamin A is derived from a variety of CAROTENOIDS found in plants. It is enriched in the liver, egg yolks, and the fat component of dairy products.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)Cell Cycle: The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.Amoeba: A genus of ameboid protozoa. Characteristics include a vesicular nucleus and the formation of several lodopodia, one of which is dominant at a given time. Reproduction occurs asexually by binary fission.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.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.Glyceraldehyde-3-Phosphate Dehydrogenases: Enzymes that catalyze the dehydrogenation of GLYCERALDEHYDE 3-PHOSPHATE. Several types of glyceraldehyde-3-phosphate-dehydrogenase exist including phosphorylating and non-phosphorylating varieties and ones that transfer hydrogen to NADP and ones that transfer hydrogen to NAD.HydroquinonesNAD: A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)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.Love: Affection; in psychiatry commonly refers to pleasure, particularly as it applies to gratifying experiences between individuals.Anxiety: Feeling or emotion of dread, apprehension, and impending disaster but not disabling as with ANXIETY DISORDERS.Marriage: The social institution involving legal and/or religious sanction whereby individuals are joined together.Vasoplegia: Condition of low SYSTEMIC VASCULAR RESISTANCE that develops secondary to other conditions such as ANAPHYLAXIS; SEPSIS; SURGICAL SHOCK; and SEPTIC SHOCK. Vasoplegia that develops during or post surgery (e.g., CARDIOPULMONARY BYPASS) is called postoperative vasoplegic syndrome or vasoplegic syndrome.Quebec: A province of eastern Canada. Its capital is Quebec. The region belonged to France from 1627 to 1763 when it was lost to the British. The name is from the Algonquian quilibek meaning the place where waters narrow, referring to the gradually narrowing channel of the St. Lawrence or to the narrows of the river at Cape Diamond. (From Webster's New Geographical Dictionary, 1988, p993 & Room, Brewer's Dictionary of Names, 1992, p440)Awards and Prizes

Characterization of K+ currents underlying pacemaker potentials of fish gonadotropin-releasing hormone cells. (1/2760)

Endogenous pacemaker activities are important for the putative neuromodulator functions of the gonadotropin-releasing hormone (GnRH)-immunoreactive terminal nerve (TN) cells. We analyzed several types of voltage-dependent K+ currents to investigate the ionic mechanisms underlying the repolarizing phase of pacemaker potentials of TN-GnRH cells by using the whole brain in vitro preparation of fish (dwarf gourami, Colisa lalia). TN-GnRH cells have at least four types of voltage-dependent K+ currents: 1) 4-aminopyridine (4AP)-sensitive K+ current, 2) tetraethylammonium (TEA)-sensitive K+ current, and 3) and 4) two types of TEA- and 4AP-resistant K+ currents. A transient, low-threshold K+ current, which was 4AP sensitive and showed significant steady-state inactivation in the physiological membrane potential range (-40 to -60 mV), was evoked from a holding potential of -100 mV. This current thus cannot contribute to the repolarizing phase of pacemaker potentials. TEA-sensitive K+ current evoked from a holding potential of -100 mV was slowly activating, long lasting, and showed comparatively low threshold of activation. This current was only partially inactivated at steady state of -60 to -40 mV, which is equivalent to the resting membrane potential. TEA- and 4AP-resistant sustained K+ currents were evoked from a holding potential of -100 mV and were suggested to consist of two types, based on the analysis of activation curves. From the inactivation and activation curves, it was suggested that one of them with low threshold of activation may be partly involved in the repolarizing phase of pacemaker potentials. Bath application of TEA together with tetrodotoxin reversibly blocked the pacemaker potentials in current-clamp recordings. We conclude that the TEA-sensitive K+ current is the most likely candidate that contributes to the repolarizing phase of the pacemaker potentials of TN-GnRH cells.  (+info)

An intrinsic oscillation in interneurons of the rat lateral geniculate nucleus. (2/2760)

By using the whole cell patch recording technique in vitro, we examined the voltage-dependent firing patterns of 69 interneurons in the rat dorsal lateral geniculate nucleus (LGN). When held at a hyperpolarized membrane potential, all interneurons responded with a burst of action potentials. In 48 interneurons, larger current pulses produced a bursting oscillation. When relatively depolarized, some interneurons produced a tonic train of action potentials in response to a depolarizing current pulse. However, most interneurons produced only oscillations, regardless of polarization level. The oscillation was insensitive to the bath application of a combination of blockers to excitatory and inhibitory synaptic transmission, including 30 microM 6,7-dinitroquinoxaline-2,3-dione, 100 microM (+/-)-2-amino-5-phosphonopentanoic acid, 20 microM bicuculline, and 2 mM saclofen, suggesting an intrinsic event. The frequency of the oscillation in interneurons was dependent on the intensity of the injection current. Increasing current intensity increased the oscillation frequency. The maximal frequency of the oscillation was 5-15 Hz for most cells, with some ambiguity caused by the difficulty of precisely defining a transition from oscillatory to regular firing behavior. In contrast, the interneuron oscillation was little affected by preceding depolarizing and hyperpolarizing pulses. In addition to being elicited by depolarizing current injections, the oscillation could also be initiated by electrical stimulation of the optic tract when the interneurons were held at a depolarized membrane potential. This suggests that interneurons may be recruited into thalamic oscillations by synaptic inputs. These results indicate that interneurons may play a larger role in thalamic oscillations than was previously thought.  (+info)

Gating of afferent input by a central pattern generator. (3/2760)

Intracellular recordings from the sole proprioceptor (the oval organ) in the crab ventilatory system show that the nonspiking afferent fibers from this organ receive a cyclic hyperpolarizing inhibition in phase with the ventilatory motor pattern. Although depolarizing and hyperpolarizing current pulses injected into a single afferent will reset the ventilatory motor pattern, the inhibitory input is of sufficient magnitude to block afferent input to the ventilatory central pattern generator (CPG) for approximately 50% of the cycle period. It is proposed that this inhibitory input serves to gate sensory input to the ventilatory CPG to provide an unambiguous input to the ventilatory CPG.  (+info)

The biological clock of very premature primate infants is responsive to light. (4/2760)

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)

Loss of the circadian clock-associated protein 1 in Arabidopsis results in altered clock-regulated gene expression. (5/2760)

Little is known about plant circadian oscillators, in spite of how important they are to sessile plants, which require accurate timekeepers that enable the plants to respond to their environment. Previously, we identified a circadian clock-associated (CCA1) gene that encodes an Myb-related protein that is associated with phytochrome control and circadian regulation in plants. To understand the role CCA1 plays in phytochrome and circadian regulation, we have isolated an Arabidopsis line with a T DNA insertion that results in the loss of CCA1 RNA, of CCA1 protein, and of an Lhcb-promoter binding activity. This mutation affects the circadian expression of all four clock-controlled genes that we examined. The results show that, despite their similarity, CCA1 and LHY are only partially redundant. The lack of CCA1 also affects the phytochrome regulation of gene expression, suggesting that CCA1 has an additional role in a signal transduction pathway from light, possibly acting at the point of integration between phytochrome and the clock. Our results indicate that CCA1 is an important clock-associated protein involved in circadian regulation of gene expression.  (+info)

How does beta-adrenergic stimulation increase the heart rate? The role of intracellular Ca2+ release in amphibian pacemaker cells. (6/2760)

1. The mechanism by which sympathetic transmitters increase the firing rate of pacemaker cells was explored in isolated cells from the sinus venosus of the cane toad Bufo marinus. Intracellular calcium concentration ([Ca2+]i) was measured with indo-1 and membrane potential and currents were recorded with the nystatin perforated-patch technique. 2. Adrenaline or isoprenaline (2 microM) increased the transient rise in [Ca2+]i and increased the firing rate; these effects were blocked by propranolol (2 microM). 3. To determine whether the changes in [Ca2+]i might influence the firing rate we studied agents which affect either the loading or the release of Ca2+ from the sarcoplasmic reticulum (SR). Rapid application of caffeine (10 mM) to spontaneously firing cells caused a large Ca2+ release from the SR and the cells were then quiescent for 24 s. In the presence of beta-adrenergic stimulation the caffeine-induced [Ca2+]i was 14 % larger but the period of quiescence after application was reduced to 12 s. 4. Ryanodine, at either low (1 microM) or high (> 10 microM) concentration, stopped firing. However, when the SR store content of Ca2+ was tested with caffeine, at low ryanodine concentration the SR Ca2+ store was empty whereas at the high concentration the SR store was still loaded with Ca2+. beta-Adrenergic stimulation was not able to restore firing at the low concentration of ryanodine but did restore firing at the high ryanodine concentration. 5. An SR Ca2+ pump blocker, 2, 5-di(tert-butyl)-1,4-hydroquinone (TBQ) which depletes the SR store of Ca2+, also rapidly and reversibly stopped spontaneous firing. 6. The relation between the amplitude of the [Ca2+]i transient and firing rate established in the presence of ryanodine was similar when firing was restored by beta-stimulation. 7. In both spontaneously firing and voltage-clamped cells, depleting the SR store with either ryanodine or TBQ suggested that about half of the Ca2+ which contributes to the calcium transient is released from the SR. 8. These results show that the amplitude of the [Ca2+]i transient is an important factor in the firing rate of toad pacemaker cells and consequently agents which modify SR Ca2+ release influence firing rate. The effects of beta-stimulation on firing rate seem to be largely mediated by changes in amplitude of the [Ca2+]i transient.  (+info)

Role of PI3-kinase in the development of interstitial cells and pacemaking in murine gastrointestinal smooth muscle. (7/2760)

1. Development of the pacemaker system in the small intestine depends upon signalling via tyrosine kinase (Kit) receptors. The downstream pathways initiated by Kit in interstitial cells of Cajal (ICC) have not been investigated. Wortmannin and 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY 294002), inhibitors of phosphatidylinositol 3'-kinase (PI3-kinase), were used to test the involvement of this pathway in the development and maintenance of ICC and electrical rhythmicity in the murine small intestine. 2. ICC and electrical slow waves were present in the murine jejunum at birth. ICC and electrical rhythmicity continued to develop in neonates such that adult activity was recorded after 1 week. Development of ICC and rhythmicity were maintained in organ culture. 3. Wortmannin or LY 294002 inhibited the development of slow waves and blocked rhythmicity within 2-4 days. Loss of slow waves was preceded by disappearance of Kit-positive cells from the myenteric (IC-MY) and deep muscular plexus (IC-DMP) regions. Wortmannin or LY 294002 had no acute effect on slow waves. 4. Muscles from older animals (day 10-day 30) developed resistance to wortmannin treatment, but when the exposure to wortmannin was increased to 35 days, damage to ICC networks and electrical dysrhythmias were observed. 5. PI3-kinase appears to be a critical downstream signalling element linking Kit receptors to ICC development and maintenance of phenotype. ICC are more sensitive to Kit or PI3-kinase blockade at birth, but the importance of the PI3-kinase signalling in the maintenance of ICC persists into adulthood. Interference with PI3-kinase signalling in immature or adult animals could result in disruption of ICC and gastrointestinal dysrhythmias.  (+info)

Regulation of mammalian circadian behavior by non-rod, non-cone, ocular photoreceptors. (8/2760)

Circadian rhythms of mammals are entrained by light to follow the daily solar cycle (photoentrainment). To determine whether retinal rods and cones are required for this response, the effects of light on the regulation of circadian wheel-running behavior were examined in mice lacking these photoreceptors. Mice without cones (cl) or without both rods and cones (rdta/cl) showed unattenuated phase-shifting responses to light. Removal of the eyes abolishes this behavior. Thus, neither rods nor cones are required for photoentrainment, and the murine eye contains additional photoreceptors that regulate the circadian clock.  (+info)

The tick-tock of your biological clock may have just gotten a little louder.. Researchers at the University of Georgia report that the number of genes under control of in living things than suspected only a few years ago. The biological clock in a much-studied model organism is dramatically higher than previously reported. The new study implies that the clock may be much more important. "This new finding may help to explain why the clock is so far-reaching in its effects on the organism," said Jonathan Arnold, a professor in the UGA department of genetics and director of the research project. "We found that some 25 percent of the genes in our model organism appear to be under clock control. I wasnt suspecting anything remotely like that.". The new research, just published in the Public Library of Science One, also shows how Arnolds team used a new methodology called Computing Life to yield these new discoveries about biological clocks. And this tool of systems biology was the key to showing ...
December 31, 2008. Science Daily/Hebrew University of Jerusalem. Indulgence in a high-fat diet can not only lead to overweight because of excessive calorie intake, but also can affect the balance of circadian rhythms - everyones 24-hour biological clock, Hebrew University of Jerusalem researchers have shown.. The biological clock regulates the expression and/or activity of enzymes and hormones involved in metabolism, and disturbance of the clock can lead to such phenomena as hormone imbalance, obesity, psychological and sleep disorders and cancer.. While light is the strongest factor affecting the circadian clock, Dr. Oren Froy and his colleagues of the Institute of Biochemistry, Food Science and Nutrition at the Hebrew Universitys Robert H. Smith Faculty of Agriculture, Food and Environment in Rehovot, have demonstrated in their experiments with laboratory mice that there is a cause-and-effect relation between diet and biological clock imbalance.. To examine this thesis, Froy and his ...
Ivanhoe Newswire) -- If you regularly experience the pangs of jet lag or a crazy work schedule, then you may not be the biggest fan of your bodys biological clock. Fortunately, a new molecular compound dubbed "longdaysin" has recently shown the ability to trick it into slowing down or speeding up to potentially meet different needs.. Researchers at the University of California San Diego and three other research centers found longdaysin by conducting an automated screening of over 120,000 compounds using a robot designed to test the effects of the compounds on a series of human bone cancer cells. These cells were genetically altered with two genes: an attached clock gene, which stimulates the cells circadian rhythm, and a luciferase gene, which lights up when the biological clock was triggered (also seen in the glow of fireflies). The robot was programmed to isolate the molecules that showed the greatest effects on the cells biological clocks. After discovering longdaysin to be the most ...
NYU (US) - Biologists have uncovered one way that biological clocks control neuronal activity-a discovery that sheds new light on sleep-wake cycles. "The findings answer a significant question-how biological clocks drive the activity of clock neurons, which, in turn, regulate behavioral rhythms," explains Justin Blau, an associate professor in New York Universitys department of biology and the studys senior author.. Their findings, which also offer potential new directions for research into ways to address sleep disorders and jetlag, appear in the Journal of Biological Rhythms.. [sources]. Scientists have known that our biological clocks control neuronal activity. But not previously understood is how this process occurs-that is, how does information from biological clocks drive rhythms in the electrical activity of pacemaker neurons that, in turn, drives daily rhythms?. To understand this mechanism, the researchers examined the biological, or circadian, clocks of Drosophila fruit flies, which ...
2010. 26cm. Pp.280. Hardbound.Biological Clock in Fish reviews the state of knowledge in sufficient detail and presents the latest contributions to the field, showing fish provide a unique model of the circadian biological clock. 1578086752
Cellular and Molecular Bases of Biological Clocks: Models and Mechanisms for Circadian Timekeeping by Leland N. Jr. Edmunds and a great selection of similar Used, New and Collectible Books available now at AbeBooks.com.
Published in the journal BMC Biology, these results show for the first time that directly targeting the biological clock in a cancerous tumour has an impact on its development.. Most of the cells in the human body have an internal clock that sets a rhythm for the activities of our organs according to the time of the day. Cancer cells, however, often have a non-functioning or malfunctioning clock.. "There were indications suggesting that the malfunctioning clock contributed to rapid tumour growth, but this had never been demonstrated. Thanks to the use of a chemical or a thermic treatment, we succeeded in repairing these cells clock and restoring it to its normal functioning. In these conditions, tumour growth drops nearly in half," explains Cermakian, who is also Director of the Laboratory of Molecular Chronobiology at the Douglas Mental Health University Institute, one of the research centres of the CIUSSS de lOuest-de-lÎle-de-Montréal.. Although this preclinical demonstration was done ...
NADH oxidases at the external surface of plant and animal cells (ECTO-NOX proteins) exhibit stable and recurring patterns of oscillations with potentially clock-related, entrainable, and temperature-compensated period lengths of 24 min. To determine if ECTO-NOX proteins might represent the ultradian time keepers (pacemakers) of the biological clock, COS cells were transfected with cDNAs encoding tNOX proteins having a period length of 22 min or with C575A or C558A cysteine to alanine replacements having period lengths of 36 or 42 min. Here we demonstrate that such transfectants exhibited 22, 36, or 40 to 42 h circadian patterns in the activity of glyceraldehyde-3-phosphate dehydrogenase, a common clock-regulated protein, in addition to the endogenous 24 h circadian period length. The fact that the expression of a single oscillatory ECTO-NOX protein determines the period length of a circadian biochemical marker (60 X the ECTO-NOX period length) provides compelling evidence that ECTO-NOX proteins ...
A new study of molecular interactions central to the functioning of biological clocks explains how certain mutations can shorten clock timing, making some people extreme morning larks because their internal clocks operate on a 20-hour cycle instead of being synchronized with the 24-hour cycle of day and night.
The day and night cycle influences the body function in health and disease through the modulation of the biological clock in via the suprachiasmatic nucleus (SCN) which i..
The influence of noise is unavoidable in all living systems. Its impact on a model of a biological clock, normally running in regular oscillating modes, is examined. It is shown that in a specific system in which endogenous rhythmicity is produced by a beat oscillator acting on a feedback coupled metabolic pool system, noise can act coherently to produce unexpected dynamic behaviour, running from regular over pseudo-regular to irregular time-structures. If the biological system consists of a set of identical weakly coupled cells, stochasticity may lead to phase decoupling producing irregular spatio-temporal patterns. Synchronization via phase resetting can be achieved by external short-time temperature pulses. Explicit results are obtained for the well-studied circadian photosynthesis oscillations in plants performing crassulacean acid metabolism. Because of the generic structure of the underlying nonlinear dynamics they can, however, be regarded as a general property of the influence of noise ...
Alarm Clock Gene KDM5A Explains Wake-up Function of Biological Clock. Ever wondered why you wake up in the morning-even when the alarm clock isnt making jarring noises? Wonder no more.
Women in their 30s and early 40s who want to know whether their biological clocks are running out should skip fertility testing, a new study suggests.
Tricking algaes biological clock to remain in its daytime setting can dramatically boost the amount of valuable compounds these simple marine plants can produce when grown in constant light.
Washington, Aug 16 (ANI): Eyes use light to regulate the biological clock through a mechanism that is different from the ability to see, according to researchers at the University of Virginia. The finding
Researchers from the Vanderbilt University say that constant exposure to artificial light may interfere with the normal development of premature babies biological clocks.
Today I am grateful to science - it is som amazing, discovering and verifying the most amazing things! I was listening to the lecture of this Soviet scientist, Simon Shnoll, and he was telling about biological clocks that run in every living organism, and how they are aligned with the movements of earth, moon, and the…
Does the biological clock in cancer cells influence tumour growth? Yes, according to a study conducted by Nicolas Cermakian, a professor in McGill Universitys Department of Psychiatry.
Jennifer L. Fleissner; The Biological Clock: Edith Wharton, Naturalism, and the Temporality of Womanhood. American Literature 1 September 2006; 78 (3): 519-548. doi: https://doi.org/10.1215/00029831-2006-024. Download citation file:. ...
The homodimeric, growth-related and time-keeping constitutive hydroquinone oxidase ENOX1 of the eukaryotic cell surface capable of oxidizing extracellular NAD(P)H and intracellular hydroquinones...
In modern societies, the risk of developing metabolic disorders such as obesity or type-2 diabetes is associated with the prevalence of psychosocial stress. Therefore, an improved understanding of adaptive stress responses and their underlying molecular mechanisms is of high clinical interest. In response to an acute stressor, animals activate the sympathetic nervous system and the hypothalamus pituitary adrenal (HPA) axis releasing catecholamines and glucocorticoids (GCs) into the circulation. Recent data suggest that stress responses are also regulated by the endogenous circadian clock adapting physiology and behavior to the environmental changes brought about by the Earth s rotation around its axis. Thus, the timing of stress may critically affect adaptive responses to and the pathological effects of repetitive stressor exposure. We have studied the role of different tissue clocks on the regulation of HPA axis activity in mice. We further characterized the impact of predictable social defeat ...
Our bodies run on an in-built 24-hour clock embedded in a part of the brain called the suprachiasmatic nucleus (SCN). Its 20,000 nerve cells sit in the middle of the brain above the back of the eyes and on top of a structure called the hypothalamus. These are the bodys master timekeepers, setting the rhythm…
The general behavior of coupled neural oscillators is very difficult to analyze, however limiting cases can be treated ([22]). We will describe one method, the method of averaging, that has been used successfully to study the dynamics of two or more neural oscillators that are weakly coupled (e.g., Hansel [16] and Ermentrout and Kopell [9]). In this limit the coupling is sufficiently weak that each oscillators trajectory remains close to its intrinsic limit cycle. The primary effect of the coupling is to perturb the relative phase between the oscillators much as we described above. However, since the perturbation per cycle is small (with weak coupling) the net effect occurs only over many cycles and the per cycle effect is seen as averaged. For illustration, we summarize the use of averaging to describe the phase-locking properties of two identical Morris-Lecar oscillators when coupled with identical mutually excitatory synapses. Detailed derivations of the equations can be found in the above ...
γ oscillations are observed in the local field potential (LFP), which emerges as a result of spatially organized, summed current flow largely due to synaptic activity within a neural network (Mitzdorf, 1985; Barth et al., 1989; Einevoll et al., 2013). γ is the result of rhythmic synaptic output from cohorts of neurons with precise temporal relationships. However, there are varied mechanisms by which these temporal patterns occur within local neural circuits.. In the hippocampus, extensive exploration of computational and experimental models has identified multiple network mechanisms by which γ oscillations can be generated. Experimental work using pharmacological manipulations of the in vitro hippocampal slice preparation found that the 40 Hz-range field potential oscillations evoked under different circumstances exhibited different reliance on synaptic excitation and inhibition. γ oscillations induced by activating mGluR (Whittington et al., 1995) or kainate (Fisahn et al., 2004) receptors ...
Hendricks, J. C., Lu, S. M., Kume, K., Yin, J. C. P., Yang, Z. H., Sehgal, A. (2003) Gender dimorphism in the role of cycle (BMAL1) in rest, rest regulation, and longevity in Drosophila melanogaster. Journal of Biological Rhythms, 18 (1). pp. 12-25. ISSN 0748-7304 Hengartner, M. O. (1997) Genetic control of programmed cell death and aging in the nematode Caenorhabditis elegans. Experimental Gerontology, 32 (4-5). pp. 363-74. ISSN 0531-5565 (Print) ...
Using the clock, researchers can gauge the age of diverse human organs and tissues. Unexpectedly, they found some parts of the anatomy, like womens breast ...
Numerous processes in our body fluctuate in a regular pattern during the day. These circadian (or daily) variations can be driven by local oscillators present within our cells or by systemic signals controlled by the master ...
division and reproduction of all cells from the single-celled amoeba to cells in the human body. The complexity and coordination of this cycle is staggering. The cell cycle is divided into four primary phases: G1, S, G2, and M.. G1, or the Gap 1 phase, is the time in which cells carry out all of the normal processes of the cell. Some cells remain in this phase for very long periods of time. But, when appropriate stimuli are encountered by a cell, a round of cell division is triggered. This point of no return is known as the restriction point. Once a cell passes this point, it must complete the entire cell cycle and return once more to G1. After a cell reproduces, it must prepare for the next phase of the cell cycle: S-phase or DNA synthesis phase. This preparation requires activating countless genes and making many new proteins that are used only during this one phase of the cell cycle. Once every component is ready, S-phase may begin.. During the DNA synthesis phase, the cell must make an exact ...
division and reproduction of all cells from the single-celled amoeba to cells in the human body. The complexity and coordination of this cycle is staggering. The cell cycle is divided into four primary phases: G1, S, G2, and M.. G1, or the Gap 1 phase, is the time in which cells carry out all of the normal processes of the cell. Some cells remain in this phase for very long periods of time. But, when appropriate stimuli are encountered by a cell, a round of cell division is triggered. This point of no return is known as the restriction point. Once a cell passes this point, it must complete the entire cell cycle and return once more to G1. After a cell reproduces, it must prepare for the next phase of the cell cycle: S-phase or DNA synthesis phase. This preparation requires activating countless genes and making many new proteins that are used only during this one phase of the cell cycle. Once every component is ready, S-phase may begin.. During the DNA synthesis phase, the cell must make an exact ...
Prior to dying the cell creates an "offspring" which carries on the same cellular characteristics as the mother cell. Because of the cellular damage done by cancer cells, the biological clock is altered and cancer cells do not die but proliferate. So not only does the mother cancer cell not die, but the offspring inherit the same characteristics as the mother which includes a broken biological clock.. As a result of this cancer cell population explosion, tumors are formed.. Haelan repairs the cellular damage and as a by product of this repair restores the normal programmed cell death (apoptosis) and cells resume their normal biologically determined cell death cycle. Since all cells resume their death cycle, cancer cells cease to grow and consequently die off.. 4. Increases the cyto-toxic effect of the NK Killer cells - Natural Killer cells (or NK cells) constitute a major component of the innate immune system. They play a major role in the rejection of tumors and cells infected by viruses. The ...
The acceleration in genome sequencing capacity is just incredible. In May 2010, I posted on the sequencing of the complete genomes of two parents and two of their kids. Now in August of 2012 we have the results on the complete genomes of 78 parent children trios, along with 1,859 complete sequences from the same…
They dont really supply proper data for survivorship at 1 year, while at 2 years, a close analysis shows 13% and 9% increases in mean and max LS (vs. GFP), but ALL of these animals are well within the historical norm for C57Bl/6 LS. Again - husbandry is a huge, huge issue in these types of studies - if I can get to the same or greater max or mean LS through proper husbandry, then your entire study is invalidated, because whatever treatment you are giving might merely be alleviating bad husbandry, and not a true life extension (example, if the diet you give the animals, lacks in f.ex. a vital vitamin, and you supply that vitamin and now extend the life span of the supplemented animals vs the improperly fed ones, what kind of life extension is this - it certainly is not compared to animals properly fed... i.e. your vitamin supplement would fail to extend the lifespan of properly fed animals). This is why it is critical to show max or mean LS extension against lifespan records of a given line ...
A new method for egg freezing called vitrification-a technology that its architects say will revolutionize the world of assisted reproduction -- is making the process of in vitro fertilization (IVF) less costly and more efficient than ever before.
Japanese researchers have developed a compound that can speed up the flowering of plants, a finding that could be used to allow agriculture even in colder
For this study, AMH levels were measured in 144 healthy, fertile women and the data were used to determine an estimate of mean AMH as a function of age. This information was then used to estimate the distribution of the age of menopause in a sample of 3,384 women between the ages of 50 and 70. Researchers were then able to develop a model based on AMH level and age that could predict age at menopause for individual women ...
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MangaHelpers is a place where you can find translations and scanlations for Shonen Manga, Shoujo Manga, Jyousei Manga as well as downloads for all your favorite manga series. MangaHelpers also is a community resource that helps translators and scanlators get their work known to a wider audience and thus increasing the popularity of lesser known Manga.
Modern reproductive technologies can give older women the same chances of having a baby as younger women, researchers reported Wednesday. The new study
From a young age Ive preferred babies to animals. Babies laugh at things adults find unamusing. They coo freely as if cantillating inner satisfaction. They are squishy and snuggly and impressed by my singing voice.
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When Sarah Gardner was 34, she started getting really worried about whether she'd ever have kids. "I bought this kit online that said that they
Sustained molecular oscillations are ubiquitous in biology. The obtained oscillatory patterns provide vital functions as timekeepers, pacemakers and spacemarkers. Control-theory type models have been introduced to explain how specific oscillatory behaviors stem from protein interaction feedbacks, whereas the energy dissipation through the oscillating processes and its role in the regulatory function remain elusive. Here we developed a general framework to assess oscillators regulation performance at different dissipation levels. Using Escherichia coli MinCDE oscillator as model system, we showed that, unlike stationary regulators monotonic performance-to-cost relation, excess dissipation at certain steps in the oscillating process damages the oscillators regulatory performance. We further discovered that ATP hydrolysis energy has to be strategically assigned to the MinE-aided MinD release and the MinD immobilization steps for optimal performance, and higher energy budget improves the ...
Everyone is equipped with a biological clock, a region in the brain of the size of a corn kernel, which dictates our sleep-wake cycles. A research conducted by Kent State professor David Glass has shown that this clock can be re-set, reported science portal EurekAlert ...
How does the body know how old it is? Our metabolisms change as we get older, even though our DNA doesnt change. Different genes are activated at different times of life, and the timing of gene expression is what controls growth, development, sexual maturity, and perhaps aging as well. The body keeps accurate track of how old it is, though there has been no scientific agreement about where the clocks are, or how they work. Recently, some biologists have suggested that one such biological clock might reside in the epigenetic state of the DNA. If this is true, epigenetics will become an attractive, though challenging, target for anti-aging research. If we knew where the body kept its "clock", then perhaps we could target the clock itself with biochemical interventions. We would not just be able to slow the progress of aging, but reset the clock to an earlier age.. DNA is decorated with methyl groups, small molecular add-ons that act like "Do Not Disturb" signs for the underlying gene. A gene that ...
Route to chaos (or periodicity) in dynamical systems is one of fundamental problems. Here, dynamical behaviors of coupled chaotic Rössler oscillators on complex networks are investigated and two different types of periodic windows with the variation of coupling strength are found. Under a moderate coupling, the periodic window is intermittent, and the attractors within the window extremely sensitively depend on the initial conditions, coupling parameter, and topology of the network. Therefore, after adding or removing one edge of network, the periodic attractor can be destroyed and substituted by a chaotic one, or vice versa. In contrast, under an extremely weak coupling, another type of periodic window appears, which insensitively depends on the initial conditions, coupling parameter, and network. It is sustained and unchanged for different types of network structure. It is also found that the phase differences of the oscillators are almost discrete and randomly distributed except that ...
They are the bodys natural steroid hormones that regulate blood sugar levels-their job is to make sure peoples blood sugar levels are lowered while they sleep and then raised when they wake; this allows people to maximize the efficiency their energy use. Glucocortids also interact with anti-inflammatory drugs and this has exposed the missing-link between cryptochromes and Glucocortids. Together, they regulate the blood sugar and the biological rhythms or what is often called the biological clock.. While scientists and doctors plan to harness this information for pharmaceutical purposes, it can also be used to help people understand their bodys natural rhythms. This way, people can be more conscious of both what they eat and how their body is using what they eat based on their sleep and rest patterns. Think about it. When are people most active during the day? When are they least active? It is important for people to take the time to get to know their activity levels and then find a way to eat ...
Hello all - I hope you dont mind me joining your forum. I go by JMC, and will give you a little background before I launch into my questions. My DH and I are both 38yo and have been married for almost 3 years. We have a DD (20 months) conceived naturally 2 months after we got married. For our second, we tried for about 6-7 months when we were told to stop using KY jelly (we are freakin idiots). After we stopped, we were PG again in 2 months. We were so excited esp. since weve got biological clock issues. That one miscarried and we were devastated. We couldnt believe it. We had zero issues with our first. We went in for an IUI last month to speed things along and were SHOCKED to be told DH had very few good sperm. The reason this shocked us was because we got PG twice in very little time. It doesnt seem right that this would be possible if there was a sperm problem (maybe once, but not twice, and certainly not in 2 short cycles each time). But we redid the sperm test and it didnt look any ...
Shes not alone: Caroline Levines biological clock is ticking loudly. She is 57 years old and has no grandchildren. -- from The Wall Street Journal
WRITER Rachel Lehmann-Haupt felt her biological clock ticking and settled on having the choice of babies in later life with the help of new technology.
Instead of letting your biological clock decide when your pregnancy window closes, discover how pregnancy with donor eggs may be the key later in life.
You can hit the snooze button on your biological clock, but freezing eggs takes time, money, and elbow grease. And its still not a sure bet.
Freezing human eggs can be successful in treating infertility-but U.S. guidelines issued Friday still urge caution for women hoping to pause a ticking biological clock.
Freezing human eggs can be successful in treating infertility - but guidelines issued Friday still urge caution for women hoping to pause a ticking biological clock.
What makes your socks antibacterial? Most likely the fabric has been treated with nano sized particles of silver, but what are the nanosilver dangers?
Laboratory: National Institute of Aging (NIA). Technology: Engineered biological pacemaker. Opportunity: The NIAs Cellular Biophysics Section is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize biological pacemakers.. Details: The technology developed by NIA consists of biological pacemakers engineered to generate normal heart rhythm. These pacemakers are created by administering in vivo a viral vector comprising a nucleic acid that encodes an adenylyl cyclase into electrically excitable cardiomyocytes of the heart of a patient. Generation of rhythmic electric impulses involve coupling factors, such as cAMP-dependent PKA and Ca2+-dependent CaMK II, which are regulatory proteins capable of modulating/enhancing interactions (i.e., coupling) of the sarcoplasmic reticulum-based, intracellular Ca2+ clock and the surface membrane voltage clock, thereby converting irregularly or rarely spontaneously active ...
Objectives and Hypotheses. Our objectives are to define the scope and problems related to biological clock disorders in children with ONH and to develop effective treatments for this condition. Based on our observations, we hypothesize: (1) Daily rest-activity patterns and sleep will be abnormal in up to 50% of children with ONH. (2) It is possible to identify risk factors for abnormal circadian system function and sleep problems in ONH. (3) Nocturnal melatonin administration will improve abnormal sleep and activity patterns in children with ONH.. Design: These studies will involve collaborative efforts between Yale University and Dr. Mark Borchert of Childrens Hospital Los Angeles, who follows the largest population of children with ONH in the world. We will study children ages 2-10 years with documented ONH using standard criteria. Based on these criteria, we have more than 100 eligible patients.. To test our hypotheses, we will: (1) examine expressed rhythmicity in children with ONH. These ...
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TY - JOUR. T1 - Drosophila Pacemaker Neurons Require G Protein Signaling and GABAergic Inputs to Generate Twenty-Four Hour Behavioral Rhythms. AU - Dahdal, David. AU - Reeves, David C.. AU - Ruben, Marc. AU - Akabas, Myles H.. AU - Blau, Justin. PY - 2010/12/9. Y1 - 2010/12/9. N2 - Intercellular signaling is important for accurate circadian rhythms. In Drosophila, the small ventral lateral neurons (s-LNvs) are the dominant pacemaker neurons and set the pace of most other clock neurons in constant darkness. Here we show that two distinct G protein signaling pathways are required in LNvs for 24 hr rhythms. Reducing signaling in LNvs via the G alpha subunit Gs, which signals via cAMP, or via the G alpha subunit Go, which we show signals via Phospholipase 21c, lengthens the period of behavioral rhythms. In contrast, constitutive Gs or Go signaling makes most flies arrhythmic. Using dissociated LNvs in culture, we found that Go and the metabotropic GABAB-R3 receptor are required for the inhibitory ...
AC (29) ADHD (30) affect (1) aging (22) Alzheimers (3) American Indians (1) anterior cinglate (1) APA (1) aphasia (5) apraxia (3) Aspergers (1) ATI (1) attention (56) attentional control (32) auditory (14) Auditory Neuroscience Lab (2) autism (6) automatic timing (8) background noise (1) basal ganglia (16) beat perception (4) beat production (4) biofeedback (1) book nook (21) BPR3 (1) brain structures (24) brain beat (1) brain carnival (34) brain clock (122) Brain Clock Blog (2) brain clock timing (2) brain facts (2) brain fitness (119) brain function (3) brain injury (25) brain location (28) Brain network integration (1) brain network segregation (1) brain networks (57) brain rhythm (20) brain structure (1) brain teasers (2) brain timing (1) brain training (14) brainstem (2) BRAMS lab (1) Brocas area (1) caffeine (1) CAPD (2) CAT (1) CBRM (1) cerebellum (17) cerebral palsy (2) CHC (1) CHC theory (11) CHC videos (1) circadian (4) classification (1) clinical disorders (3) clocks (1) CNTRICS (1) ...
...The circadian clocks that control and influence dozens of basic biolog...,Snooze,button,on,biological,clocks,improves,cell,adaptability,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
Researchers at the Yale School of Medicine have found that when and what you eat affects the synchronization of the bodys biological clocks.. Biological clocks, which are found in every cell of the body, operate on a 24-hour cycle, according to a preview of the study written by Gerald Hart, biological chemistry professor at Johns Hopkins University. Synchronizing all the clocks in the body is essential for the body to function at its best. The three-year study, which was conducted on lab mice, found that eating at certain times of the day, which vary depending on ones sleep habits, may lead to optimal body functionality via clock synchronization. The findings were published Feb. 5 in the journal Cell Metabolism.. When food is consumed at the optimal times of the day, the bodys peripheral clocks, which are found in every cell outside the brain, synchronize with the bodys central clock, which is located in the brain and responds to external signals like light and temperature, said researcher ...
A phase resetting curve (PRC) measures the transient change in the phase of a neural oscillator subject to an external perturbation. The PRC encapsulates the dynamical response of a neural oscillator and, as a result, it is often used for predicting phase-locked modes in neural networks. While phase is a fundamental concept, it has multiple definitions that may lead to contradictory results. We used the Hilbert Transform (HT) to define the phase of the membrane potential oscillations and HT amplitude to estimate the PRC of a single neural oscillator. We found that HT’s amplitude and its corresponding instantaneous frequency are very sensitive to membrane potential perturbations. We also found that the phase shift of HT amplitude between the pre- and poststimulus cycles gives an accurate estimate of the PRC. Moreover, HT phase does not suffer from the shortcomings of voltage threshold or isochrone methods and, as a result, gives accurate and reliable estimations of phase resetting.
As promised on The Paleo Solution Podcast #270 this is the first installment of a three part blog series on sleep from Doc Parsley!. Many people have heard of the concept that humans use the sun to adjust their biological clock. The overall driver of the biological clock is the circadian-rhythm controlling the SCN (suprachiasmatic nucleus for you neuro geeks out there)-often called the "master clock".. But what does that really mean, what does the "master clock" really control, and what can we do about it?. To answer that, we have to talk a little bit of science-not too much-but some:. Humans (like every other life form on earth) use the light of the sun to regulate biological activities. Single-celled organisms and plants do it in a different way than more complex animals. We humans use our eyes. Our eyes have special nerve cells in them that sense a certain frequency of light (blue light), and let the rest of our bodies know-via our brain-what we should be preparing for. As the light decreases ...
During the 15th and 16th centuries, clockmaking flourished, particularly in the metalworking towns of Nuremberg and Augsburg, and in Blois, France. Some of the more basic table clocks have only one time-keeping hand, with the dial between the hour markers being divided into four equal parts making the clocks readable to the nearest 15 minutes. Other clocks were exhibitions of craftsmanship and skill, incorporating astronomical indicators and musical movements. The cross-beat escapement was invented in 1584 by Jost Bürgi, who also developed the remontoire. Bürgis clocks were a great improvement in accuracy as they were correct to within a minute a day.[35][36] These clocks helped the 16th-century astronomer Tycho Brahe to observe astronomical events with much greater precision than before.[citation needed][how?] ...
A model or hybrid network consisting of oscillatory cells interconnected by inhibitory and electrical synapses may express different stable activity patterns without any change of network topology or parameters, and switching between the patterns can be induced by specific transient signals. However, little is known of properties of such signals. In the present study, we employ numerical simulations of neural networks of different size composed of relaxation oscillators, to investigate switching between in-phase (IP) and anti-phase (AP) activity patterns. We show that the time windows of susceptibility to switching between the patterns are similar in 2-, 4- and 6-cell fully-connected networks. Moreover, in a network (N = 4, 6) expressing a given AP pattern, a stimulus with a given profile consisting of depolarizing and hyperpolarizing signals sent to different subpopulations of cells can evoke switching to another AP pattern. Interestingly, the resulting pattern encodes the profile of the switching
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 ...
Americans Jeffrey Hall, Michael Rosbash and Michael Young share the 2017 Nobel Prize in Physiology or Medicine for work that explained how our cells keep track of time.
Circadian clocks synchronize cellular metabolism to the diurnal light cycle. In humans, our biological clocks impact many aspects of our physiology, including s...
Bacteria will be the circadian oscillator and the cell cycle oscillator. A circadian oscillator allows cells to adapt cellular activities to
New York University and University of London scientists say theyve found more evidence that mammals and fruit flies share a common genetic makeup.
1.local time in sydney is two hours behind local time in new zealand and two hours ahead of local time in Perth. Pam has an endogenous rhythm with a period of 25 hours. which would induce the less severe jet-lag - a flight from sydney to auckland or from sydney to perth ...
All questionnaires are presented in Dutch and completed at home.. The primary outcome of depression is measured with the Geriatric Depression Scale (GDS), using the complete 30 items version [85]. The GDS is a list of statements and patients are asked to rate whether these statements are applicable to them during the last week, answering yes or no. The range of the cumulative score is 0 to 30 and scores are labeled as follows: 0-9 as "not depressed", 10-19 as "mildly depressed", and 20-30 as "severely depressed".. The Athens Insomnia Scale (AIS) is a questionnaire consisting of eight items, based on the criteria of the 10th edition of the International Classification of Diseases, (ICD-10) [86]. The total score ranges from 0 (absence of any sleep-related problem) to 24 (severe degree of insomnia). The responders are requested to rate an item as positive (i.e. to choose among rating options 1, 2 and 3) only if they have experienced any sleep difficulties at least three times a week during the ...
In the contemporary life we often are subjected to different sorts of stress. Therere many ways to relieve body stress one of which is the spa foot bath. The matter is that foot is the part of the body which is subjected to the greatest job during the working day. In fact, a foot carries the weight of the whole body all day long, so it plays an important role in the life and proper functionality of our bodies. Thus, our feet need to be correctly treated because these are extremely important parts of our body as they have the reflex access to the whole body determining the state of our health. From the economic point of view, feet are the cheapest means of transportation for human beings known on earth. Unfortunately, the feet are the parts of the human body which are seldom paid attention to by their owners, even when something wrong is happening to them. Feeling some paid in our feet we tend to think that its just a result of slight overloading during the day. But we forget about the ...
my armpit to think about and try not to disturb!). Theres also the whole: "I-just-spent-three-years-of-my-life-(plus-racked-up-tons-of-debt-and-lost-opportunity-costs**)-and-that-doesnt-even-count-the-years-of-prep-and-schooling-before-law-school" to think about. Im not saying that all that would go right out the window if I had a baby right now. But, I think that law, like many careers, is one where, rightly or wrongly, you really need to think about how having a family can change your career path. I have a dear friend right now who is a new first year associate at a law firm in Boston and I know that caring for her sweet one-week-shy-of-one-year-old, while of course joyful, has also involved a tenuous balancing game that has added stress to her life above and beyond that normal level of crazy first year associate lawyer stress. Shes racing home to pick up from daycare, spending an hour or two with her son, putting him down, and then logging back in to work from home remotely for a few more ...
For you dating doesnt need to have VERY HIGH STAKES because you have fifteen years to mess around and fall in love and try out the type of relationships you want. Some people end up with the love of their life and want to get married and have kids with that person and it ends up working out perfectly. For some people the having children option doesnt just materialize and it becomes a question of whether you are willing to settle down with someone who may not be exactly right for you and have babies or hold out for love and give that the time it takes to happen. Anyway, life doesnt always work out according to some plan and theres definitely a chance yours wont. But if you are hell bent on having a marriage and a family, you can most likely make that happen. There is someone who will want to love you and be with you. It may not be the person you want, but if you want that its almost always there. My best friend growing up was big into plans and life schedules. She told me when she was ...
William Hudson is one of a small but growing group of single young men whove chosen to store their sperm, just as single young women have stored their eggs.
A new study finds that children born to older fathers were at higher risk for autism, bipolar disorder and a range of other psychiatric problems. Does this mean that men should factor age into their family planning? Anderson asked Chief Medical Correspondent Dr. Sanjay Gupta.
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The Robinson oscillator is an electronic oscillator circuit originally devised for use in the field of continuous wave (CW) nuclear magnetic resonance (NMR). It was a development of the marginal oscillator. Strictly one should distinguish between the marginal oscillator and the Robinson oscillator, although sometimes they are conflated and referred to as a Robinson marginal oscillator. Modern magnetic resonance imaging (MRI) systems are based on pulsed (or Fourier transform) NMR; they do not rely on the use of such oscillators. The key feature of a Robinson oscillator is a limiter in the feedback loop. This means that a square wave current, of accurately-fixed amplitude, is fed back to the tank circuit. The tank selects the fundamental of the square wave, which is amplified and fed back. This results in an oscillation with well-defined amplitude; the voltage across the tank circuit is proportional to its Q-factor. The marginal oscillator has no limiter. It is arranged for the working point of ...
The occurrence of oscillations in a well-known asymptotic preserving (AP) numerical scheme is investigated in the context of a linear model of diffusive relaxation, known as the $P_1$ equations. The scheme is derived with operator splitting methods that separate the $P_1$ system into slow and fast dynamics. A careful analysis of the scheme shows that binary oscillations can occur as a result of a black-red diffusion stencil and that dispersive-type oscillations may occur when there is too little numerical dissipation. The latter conclusion is based on comparison with a modified form of the $P_1$ system. Numerical fixes are also introduced to remove the oscillatory behavior.
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 ...
This article investigates the limit cycles within type-1 linear systems under PID-type of relay feedback. The problem is generalised from the identification of friction models of servo mechanical systems via limit-cycle experiments under dual-channel relay feedback. Locations of limit cycles are given so that the exact durations between two consecutive switchings of relays can be determined via numerical computation. After this, local stability of limit cycles can be checked via the Jacobian of Poincare map. Examples are analysed using proposed theorems ...
Horvath looked at the DNA of nearly 8,000 samples of 51 different healthy and cancerous cells and tissues. Specifically, he looked at how methylation, a natural process that chemically modifies DNA, varied with age.. Horvath found that the methylation of 353 DNA markers varied consistently with age and could be used as a biological clock. The clock ticked fastest in the years up to around age 20, then slowed down to a steadier rate. Whether the DNA changes cause ageing or are caused by ageing is an unknown that scientists are now keen to work out.. "Does this relate to something that keeps track of age, or is a consequence of age? I really dont know," Horvath told the Guardian. "The development of grey hair is a marker of ageing, but nobody would say it causes ageing," he said.. The clock has already revealed some intriguing results. Tests on healthy heart tissue showed that its biological age - how worn out it appears to be - was around nine years younger than expected. Female breast tissue ...
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Researchers with Cedars-Sinai Heart Institute have announced promising results from a study testing the theory that an abnormal heart beat could be
Oscillatory instability at the Hopf bifurcation is a dynamical phenomenon that has been suggested to characterize active nonlinear processes observed in the auditory system. Networks of oscillators poised near Hopf bifurcation points and tuned to tonotopically distributed frequencies have been used as models of auditory processing at various levels, but systematic investigation of the dynamical properties of such oscillatory networks is still lacking. Here we provide a dynamical systems analysis of a canonical model for gradient frequency neural networks driven by a periodic signal. We use linear stability analysis to identify various driven behaviors of canonical oscillators for all possible ranges of model and forcing parameters. The analysis shows that canonical oscillators exhibit qualitatively different sets of driven states and transitions for different regimes of model parameters. We classify the parameter regimes into four main categories based on their distinct signal processing capabilities.
ABSTRACT:We consider a minimal cascade model previously proposed ~1 for the mitotic oscillator driving the embryonic cell division cycle. The model is based on a bicyclic phosphorylation-dephosphorylation cascade involving cyclin and cdc2 kinase. By constructing stability diagrams showing domains of periodic behavior as a function of the maximum rates of the kinases and phosphatases involved in the two cycles of the cascade, we investigate the role of these converter enzymes in the oscillatory mechanism. Oscillations occur when the balance of kinase and phosphatase rates in each cycle is in a range bounded by two critical values. The results suggest ways to arrest the mitotic oscillator by altering the maximum rates of the converter enzymes. These results bear on the control of cell proliferation. The original paper reference is cited below: Arresting the mitotic oscillator and the control of cell proliferation: insights from a cascade model for cdc2 kinase activation, Goldbeter, A. and ...
What makes you tick is a multimedia, interactive feature to explain how your biological clock affects the bodys natural rhythm and when disturbed can lead...
PHILADELPHIA - While scientists have known for several years that our bodys internal clock helps regulate many biological processes, researchers have found that the reverse is also true: Many common biological processes - including insulin metabolism - regulate the clock, according to a new study by investigators at the University of Pennsylvania School of Medicine, the Genomics Institute of the Novartis Research Foundation, and the University of California at San Diego.. The new data, published online in Cell this week, suggest that someday physicians may be able to use small molecules that inhibit or stimulate these biological processes in order to influence a persons clock when it gets out of sync due to jetlag or shift work. Researchers may also be able to find new ways to treat metabolic disorders that are intimately tied to the bodys daily cycles.. Using a genome-wide screen, the investigators found that reducing expression of any one of hundreds of genes could substantially alter the ...
A phase detector generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The control signal may be used to adjust the delay value of a voltage-controlled delay circuit in order to adjust the phase relationship between the first and second clock signals to have a predetermined phase relationship.
Nonlinear delay-differential equations represent infinite-dimensional systems for which characterising the behaviour of solutions can be technically challenging. Their appearance in many applied fields, such as population biology, is in great part due to their ability to model dynamics with non-instantaneous effects. These phenomena often exhibit behaviour which does not occur in the associated non-delayed counterpart. In particular, it is known that delays can trigger the occurrence of oscillatory behaviour and can, in several cases, bring evidence for mechanisms underlying oscillations in biological systems. Oscillatory dynamics play an important role in the accurate regulation of hormones. Such rhythms in the ultradian regime have been observed in multiple physiological areas such as the HPA-axis, phases of sleep, and the glucose regulatory system.. In this contribution, the effect of diabetic deficiencies on the production of an oscillatory ultradian regime is studied using a deterministic ...
The 9FGL6241 is an intelligent buffer/clock generator tailored for single and dual-ported nVME SSDs. It supports Common (CC) and Independent Reference (IR) clocking architectures and is ideal for U.2 and M.2 form factors. The device is also useful in PCIe master/slave and clock multiplexing applications, with an internal clock generator as a third input channel ...
Inside the suprachiasmatic nucleus (SCN) of your brain, which is part of your hypothalamus, resides your master biological clock. Based on signals of light and
Pablo Neruda - I like You Calm, As if You Were Absent (lines 17-20). o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o. Blurred darkness greeted him the moment Ryoma opened his eyes. He blinked a couple of times, trying to get the grasp of time and reality. A brief glance at the luminous clock on the nearest wall told him it was too early for perfectly sane human beings to be awake. He wondered if he did anything to mess up his biological clock since he highly doubted he was ever fully awake and functional at 4 oclock in the morning. Forcing his eyes shut and willing his mind to lull him back to the realm of sleep became irritating after a few minutes, thus prompting him to slip out of bed and out of the bedroom.. Ryoma made his way down to the kitchen with practiced stealth; it would not do to wake the other occupant of the house who was still in the state of calm, peaceful sleep. He cursed himself when the floorboards creaked under his feet and he made mental notes to ...
Have you heard about social jet-lag? This was a new-to-me term that I heard on the radio yesterday AM. According to German researcher Till Roenneberg, the disconnect between our social calendars and our biological clocks is creating a kind of jet lag - hes dubbed it social jet lag. Warning - video has annoying alarm clock noises!…
A notable feature of the PRC of C57BL/6J Per1−/− mice is its high amplitude, which is reminiscent of the light responsiveness of Clock mutant (Δ19) heterozygous mice that have large phase shifts and low-amplitude circadian oscillations in the SCN (Vitaterna et al., 2006). This is consistent with our finding that the Per1−/− SCN is arrhythmic or has a low amplitude, irregular rhythm in vitro (Pendergast et al., 2009). The PRC of Per2−/− mice has an elongated advance zone and large phase advances. In addition, Per2−/− mice have a phase-advanced PRC, suggesting that the phase relationship between the circadian pacemaker and the onset of the activity rhythm in Per2−/− mice is altered. The PRC of Per3−/− mice is similar to the PRC of wild-type mice. This is not surprising because Per3 expression is not induced in response to light (Takumi et al., 1998; Zylka et al., 1998).. PRCs have been used to make predictions according to the discrete model of entrainment, which posits ...
There a wide variety of biological theories of ageing from macro-level concepts such as evolutionary trade-offs and reliability theory to system-based theories of neuroendocrine and immune function and molecular and cellular theories such as the role of a biological clock. Animal studies can elegantly demonstrate the role of specific pathways such as insulin signalling but their relevance to human ageing remains controversial. Fundamentally, the loss of homeostatic control across a wide range of systems may suggest that no single pathway is necessary or sufficient for ageing. The new findings from GWAS studies of chronic diseases may also highlight commonality of pathways across phenotypes.. Within the context of the Halcyon programme we will present preliminary results around our work on telomeres, the hypothalamic pituitary axis and genetic variants on potential ageing traits. We will discuss future outputs as well the challenges of exploring these ideas within an epidemiological ...
There are more than 500 scientific publications advocating the use of Gerovital as an anti aging drug. Every person has his own biological clock. Aging is a process which is influenced by the genetic and environmental factors. Normal aging rhythm can be accelerated or delayed due to these factors. Aging rhythm can be controlled by […]. ...
Find it hard to wake up in the morning? This is mainly due to biological clock as well as other factors. 10 tested & effective ways may help you deal with it.
The human "biological clock". Sleep timing depends greatly on hormonal signals from the circadian clock, or Process C, a ... The circadian clock has its own set of genes.[39] Genes which may influence sleep include ABCC9,[40] DEC2,[41][42] and variants ... "Sleep and Biological Rhythms. 14: 89-99. doi:10.1007/s41105-015-0018-6. PMC 4732678. PMID 26855610.. ... The internal circadian clock is profoundly influenced by changes in light, since these are its main clues about what time it is ...
Lewis, Alan (1999). Melatonin and the Biological Clock. McGraw-Hill. p. 23. ISBN 978-0-87983-734-1.. ... Perreau-Lenz S, Pévet P, Buijs RM, Kalsbeek A (January 2004). "The biological clock: the bodyguard of temporal homeostasis". ... Guardiola-Lemaître B (December 1997). "Toxicology of melatonin". Journal of Biological Rhythms. 12 (6): 697-706. doi:10.1177/ ... Many animals use the variation in duration of melatonin production each day as a seasonal clock.[87] In animals including ...
In addition, the biological clock (which is regulated by the hypothalamus) stimulates hunger. Processes from other cerebral ...
Ishida N, Kaneko M, Allada R (August 1999). "Biological clocks". Proc. Natl. Acad. Sci. U.S.A. 96 (16): 8819-20. Bibcode: ... A homolog of CLOCK plays the same role in the human clock, and CYC is replaced by BMAL1. CRY has two human homologs, CRY1 and ... per has also been implicated in the regulation of several output processes of the biological clock, including mating activity ... Spanagel R, Rosenwasser AM, Schumann G, Sarkar DK (August 2005). "Alcohol consumption and the body's biological clock". Alcohol ...
Ishida, N; Kaneko, M; Allada, R (1999). "Biological clocks". Proc. Natl. Acad. Sci. U.S.A. 96 (16): 8819-20. doi:10.1073/pnas. ... Clock - The clock gene in Drosophila encodes for the CLOCK protein and forms a heterodimer with the protein CYCLE in order to ... In the mammalian circadian clock, for example, transcription factors CLOCK and BMAL1 are the positive regulators. CLOCK and ... Clock - Clock, also known as Circadian Locomotor Output Cycles Kaput, is a transcription factor in the circadian pacemaker of ...
Ishida, N; Kaneko, M; Allada, R (3 Aug 1999). "Biological clocks". Proc. Natl. Acad. Sci. U.S.A. 96 (16): 8819-8820. doi: ... Vrille mRNA and protein product (VRI) oscillate predictably on a 24-hour timescale and interact with other circadian clock ... 7 February 2003). "vrille, Pdp1, and dClock Form a Second Feedback Loop in the Drosophila Circadian Clock". Cell. 112 (3): 329- ... Ohno, T; Onishi, Y; Ishida, N (24 Jan 2007). "The Negative Transcription Factor E4BP4 Is Associated With Circadian Clock ...
Ishida N, Kaneko M, Allada R (August 1999). "Biological clocks". Proc. Natl. Acad. Sci. U.S.A. 96 (16): 8819-20. doi:10.1073/ ... Konopka and Orr found that light pulses reset the mutant clock to a greater extent than the wild type clock (about 10 hours for ... In contrast to Clock, Andante lengthens the period of eclosion, and locomotor activity by 1.5-2 hours, and was also shown to ... In 1990, Konopka collaborated with Mitchell S. Dushay and Jeffery C. Hall to further investigate the effects of the clock gene ...
Fisch H, Braun S (2005). The male biological clock: the startling news about aging, sexuality, and fertility in men. New York: ... "Male biological clock: a critical analysis of advanced paternal age". Fertil. Steril. 103: 1402-6. doi:10.1016/j.fertnstert. ... The paternal age effect is the statistical relationship between paternal age at conception and biological effects on the child. ... "Contrasting Effects of Maternal and Paternal Age on Offspring Intelligence: The clock ticks for men too". PLoS Med. 6 (3): e42 ...
This suggests that animals have a biological clock that can serve as a CS. This method has also been used to study timing ... An example of conditioned hunger is the "appetizer effect." Any signal that consistently precedes a meal, such as a clock ... As an adaptive mechanism, emotional conditioning helps shield an individual from harm or prepare it for important biological ...
The Biological Clocks that Control the Daily Lives of Every Living Thing[14][15] and Seasons of Life: The Biological Rhythms ... Leon Kreitzman; Russell G. Foster (2004). Rhythms of life: the biological clocks that control the daily lives of every living ... Leon Kreitzman; Russell G. Foster (2009). Seasons of Life: The Biological Rhythms That Enable Living Things to Thrive and ... From 1988 to 1995 Foster was a member of the National Science Foundation Center for Biological Rhythms at the University of ...
ISBN 0-691-02402-2. Arthur T. Winfree (1987). Timing of Biological Clocks. Scientific American Library, No 19. ISBN 0-7167-5018 ... University of Chicago 1972-1979 Associate Professor of Biological Sciences, Purdue University 1979-1986 Professor of Biological ... Cohen, Joel E. (1982). "Review: The geometry of biological time, by Arthur T. Winfree" (PDF). Bull. Amer. Math. Soc. (N.S.). 7 ... Winfree was noted for his work on the mathematical modeling of biological phenomena: from cardiac arrhythmia and circadian ...
In most cases, it is not known what causes the abnormality in the biological clocks of DSPD patients. DSPD tends to run in ... DSPD is a disorder of the body's timing system-the biological clock. Individuals with DSPD might have an unusually long ... biological clock), compared to those of the general population and societal norms. The disorder affects the timing of sleep, ... hour and have extreme difficulty waking because their biological clocks are not in phase with that schedule. Non-DSPD people ...
"Men Have Biological Clocks, Too". Retrieved 2015-09-15. "A Social History of Sperm". Barlow, Jim. "UO sociologist wins major ...
Urist, Jacoba (21 October 2013). "Men Have Biological Clocks, Too". The Atlantic. Retrieved 2 April 2014. Curtis, John (11 ...
The Physiological Clock, 1958) Biological clocks; Chairman's Address; Cold Spring Harbor Symposium (1960) Interference of ... "XXV: Biological Clocks 1960". CSHL Digital Photo Archives. Retrieved 7 April 2015. Datta, Subhash Chandra (1994). Plant ... From his results, Bünning proposed that biological clocks have sensors for both light and dark, and their relationship aids ... In 1960, he chaired in the 25th Cold Spring Harbor Symposium, "Biological Clocks". The next year, Bünning was elected ...
... has contributed tremendously towards the understanding of the biological clock of Drosophila melanogaster In 1994 ... "Experiments Illuminate Workings of Biological Clocks". Howard Hughes Medical Institute. Retrieved 2015-04-21. "New Pathway to ... Redeye levels showed changes throughout the day even when the genes which are part of the circadian clock were mutated. This ... Sehgal has been involved in the discovery of Drosophila TIM and many other important components of the Drosophila clock ...
YUFEROV, Vadim; BUTELMAN, Eduardo R; KREEK, Mary J. Biological clock: biological clocks may modulate drug addiction. European ... Clock genes as a link between addiction and obesity. European Journal of Human Genetics, január 2006, roč. 14, čís. 1, s. 5. ... Effect of fluoxetine and cocaine on the expression of clock genes in the mouse hippocampus and striatum. Neuroscience, 2005, ... Benzodiazepines as antidepressants: does GABA play a role in depression?. Biological Psychiatry, november 1995, roč. 38, čís. 9 ...
Evolving Biological Clocks using Genetic Regulatory Networks - Information page with model source code and Java applet. ... At one level, biological cells can be thought of as "partially mixed bags" of biological chemicals - in the discussion of gene ... Knabe JF, Nehaniv CL, Schilstra MJ, Quick T (2006). "Evolving Biological Clocks using Genetic Regulatory Networks". Proceedings ... Trajectories correspond to the unfolding of biological pathways and transients of the equations to short-term biological events ...
Pittendrigh is regarded as the "father of the biological clock," and founded the modern field of chronobiology alongside Jürgen ... Here, he continued his studies of biological clocks, working with the faculty and lecturing at Montana State University - ... "Perspectives in the study of biological clocks." Perspectives in Marine Biology, AA Buzati-Traverso, ed, 239-268, University of ... in establishing many of the key criteria that a biological system must have in order to be considered a biological clock. His ...
The effect is disruption of a human being's biological clock resulting in poor sleeping and rest periods. Research at the ... "Do White LEDs Disrupt our Biological Clocks?". www.insidescience.org. 19 June 2012. Retrieved 4 October 2016. http:// ...
Hall, Carl T. Study speeds up biological clocks / Fertility rates dip after women hit 27. The San Francisco Chronicle. April 30 ...
... were found to play similar roles in the mouse biological clock-and therefore almost certainly in the human biological clock as ... The first biological clock genes, for example, were identified by examining Drosophila mutants that showed disrupted daily ... The SCN contains the body's central biological clock. Neurons there show activity levels that rise and fall with a period of ... The hypothalamus is a collection of small nuclei, most of which are involved in basic biological functions. Some of these ...
"Biological clock: biological clocks may modulate drug addiction". European Journal of Human Genetics. 13 (10): 1101-3. doi: ... which is essential for resetting the biological clock.[citation needed] Recent research suggests that, outside the SCN, clock ... In mammals, circadian clock genes behave in a manner similar to that of flies. CLOCK (circadian locomotor output cycles kaput) ... The products of clock and cycle, called CLK and CYC, belong to the PAS-containing subfamily of the basic helix-loop-helix (bHLH ...
Besides its function as synchronizer of the biological clock, melatonin is a powerful free-radical scavenger and wide-spectrum ... Lewis, Alan (1999). Melatonin and the Biological Clock. McGraw-Hill. p. 23. ISBN 0-87983-734-9. Buscemi N, Vandermeer B, Hooton ... Perreau-Lenz S, Pévet P, Buijs RM, Kalsbeek A (January 2004). "The biological clock: the bodyguard of temporal homeostasis". ... Many of its biological effects in animals are produced through activation of melatonin receptors, while others are due to its ...
clock". J. Exp. Biol. 97: 121-136. Dunlap, J.; Hastings, J.W. (1981). "The biological clock in Gonyaulax. controls luciferase ... For over 50 years he also had an affiliation with the Marine Biological Laboratory in Woods Hole, Massachusetts. He was the ... In 1953 he joined the faculty in the Department of Biological Sciences at Northwestern University. In 1954 he began a long ... Johnson, C.H.; Hastings, J.W. (1986). "The elusive mechanism of the circadian clock". American Scientist. 74: 29-36. Hastings, ...
Biological process. • anterior/posterior pattern specification. • multicellular organism development. • anterior/posterior axis ...

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