The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.
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.
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 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.
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.
Circadian rhythm signaling proteins that influence circadian clock by interacting with other circadian regulatory proteins and transporting them into the CELL NUCLEUS.
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.
Geological formations consisting of underground enclosures with access from the surface.
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.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
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.
Flavoproteins are a type of protein molecule that contain noncovalently bound flavin mononucleotide or flavin adenine dinucleotide as cofactors, involved in various redox reactions and metabolic pathways, such as electron transfer, energy production, and DNA repair.
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.
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.
The absence of light.
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.
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).
A species of ascomycetous fungi of the family Sordariaceae, order SORDARIALES, much used in biochemical, genetic, and physiologic studies.
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.
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.
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.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
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.
Elements of limited time intervals, contributing to particular results or situations.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
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.
Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.

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)

"Biological clocks" refer to the internal time-keeping systems in living organisms that regulate the timing of various physiological processes and behaviors according to a daily (circadian) rhythm. These rhythms are driven by genetic mechanisms and can be influenced by environmental factors such as light and temperature.

In humans, biological clocks help regulate functions such as sleep-wake cycles, hormone release, body temperature, and metabolism. Disruptions to these internal timekeeping systems have been linked to various health problems, including sleep disorders, mood disorders, and cognitive impairment.

A circadian rhythm is a roughly 24-hour biological cycle that regulates various physiological and behavioral processes in living organisms. It is driven by the body's internal clock, which is primarily located in the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain.

The circadian rhythm controls many aspects of human physiology, including sleep-wake cycles, hormone secretion, body temperature, and metabolism. It helps to synchronize these processes with the external environment, particularly the day-night cycle caused by the rotation of the Earth.

Disruptions to the circadian rhythm can have negative effects on health, leading to conditions such as insomnia, sleep disorders, depression, bipolar disorder, and even increased risk of chronic diseases like cancer, diabetes, and cardiovascular disease. Factors that can disrupt the circadian rhythm include shift work, jet lag, irregular sleep schedules, and exposure to artificial light at night.

CLOCK proteins are a pair of transcription factors, CIRCADIAN LOComotor OUTPUT Cycles Kaput (CLOCK) and BMAL1 (brain and muscle ARNT-like 1), that play a critical role in the regulation of circadian rhythms. Circadian rhythms are biological processes that follow an approximately 24-hour cycle, driven by molecular mechanisms within cells.

The CLOCK and BMAL1 proteins form a heterodimer, which binds to E-box elements in the promoter regions of target genes. This binding activates the transcription of these genes, leading to the production of proteins that are involved in various cellular processes. After being transcribed and translated, some of these proteins feed back to inhibit the activity of the CLOCK-BMAL1 heterodimer, forming a negative feedback loop that is essential for the oscillation of circadian rhythms.

The regulation of circadian rhythms by CLOCK proteins has implications in many physiological processes, including sleep-wake cycles, metabolism, hormone secretion, and cellular proliferation. Dysregulation of these rhythms has been linked to various diseases, such as sleep disorders, metabolic disorders, and cancer.

Circadian clocks are biological systems found in living organisms that regulate the daily rhythmic activities and functions with a period of approximately 24 hours. These internal timekeeping mechanisms control various physiological processes, such as sleep-wake cycles, hormone secretion, body temperature, and metabolism, aligning them with the external environment's light-dark cycle.

The circadian clock consists of two major components: the central or master clock, located in the suprachiasmatic nucleus (SCN) of the hypothalamus in mammals, and peripheral clocks present in nearly every cell throughout the body. The molecular mechanisms underlying these clocks involve interconnected transcriptional-translational feedback loops of several clock genes and their protein products. These genetic components generate rhythmic oscillations that drive the expression of clock-controlled genes (CCGs), which in turn regulate numerous downstream targets responsible for coordinating daily physiological and behavioral rhythms.

Circadian clocks can be synchronized or entrained to external environmental cues, mainly by light exposure. This allows organisms to adapt their internal timekeeping to the changing day-night cycles and maintain proper synchronization with the environment. Desynchronization between the internal circadian system and external environmental factors can lead to various health issues, including sleep disorders, mood disturbances, cognitive impairment, metabolic dysregulation, and increased susceptibility to diseases.

The suprachiasmatic nucleus (SCN) is a small region located in the hypothalamus of the brain, just above the optic chiasm where the optic nerves from each eye cross. It is considered to be the primary circadian pacemaker in mammals, responsible for generating and maintaining the body's internal circadian rhythm, which is a roughly 24-hour cycle that regulates various physiological processes such as sleep-wake cycles, hormone release, and metabolism.

The SCN receives direct input from retinal ganglion cells, which are sensitive to light and dark signals. This information helps the SCN synchronize the internal circadian rhythm with the external environment, allowing it to adjust to changes in day length and other environmental cues. The SCN then sends signals to other parts of the brain and body to regulate various functions according to the time of day.

Disruption of the SCN's function can lead to a variety of circadian rhythm disorders, such as jet lag, shift work disorder, and advanced or delayed sleep phase syndrome.

Period (PER) circadian proteins are a group of proteins that play a crucial role in the regulation of circadian rhythms, which are physical, mental, and behavioral changes that follow a daily cycle. They are named after the PERIOD gene, whose protein product is one of the key components of the molecular circadian clock mechanism.

The molecular clock is a self-sustaining oscillator present in most organisms, from cyanobacteria to humans. In mammals, the molecular clock consists of two interlocking transcriptional-translational feedback loops that generate rhythmic expression of clock genes and their protein products with a period of approximately 24 hours.

The primary loop involves the positive regulators CLOCK and BMAL1, which heterodimerize and bind to E-box elements in the promoter regions of target genes, including PERIOD (PER) and CRYPTOCHROME (CRY) genes. Upon transcription and translation, PER and CRY proteins form a complex that translocates back into the nucleus, where it inhibits CLOCK-BMAL1-mediated transcription, thereby suppressing its own expression. After a certain period, the repressive complex dissociates, allowing for another cycle of transcription and translation to occur.

The second loop involves the regulation of additional clock genes such as REV-ERBα and RORα, which compete for binding to ROR response elements (ROREs) in the BMAL1 promoter, thereby modulating its expression level. REV-ERBα also represses PER and CRY transcription by recruiting histone deacetylases (HDACs) and nuclear receptor corepressor 1 (NCOR1).

Overall, Period circadian proteins are essential for the proper functioning of the molecular clock and the regulation of various physiological processes, including sleep-wake cycles, metabolism, hormone secretion, and cellular homeostasis. Dysregulation of these proteins has been implicated in several diseases, such as sleep disorders, metabolic syndromes, and cancer.

ARNTL (aryl hydrocarbon receptor nuclear translocator-like) transcription factors, also known as BMAL1 (brain and muscle ARNT-like 1), are proteins that bind to DNA and promote the expression of specific genes. They play a critical role in regulating circadian rhythms, which are the physical, mental, and behavioral changes that follow a daily cycle.

ARNTL transcription factors form heterodimers with another set of transcription factors called CLOCK (circadian locomotor output cycles kaput) proteins. Together, these complexes bind to specific DNA sequences known as E-boxes in the promoter regions of target genes. This binding leads to the recruitment of other cofactors and the activation of gene transcription.

ARNTL transcription factors are part of a larger negative feedback loop that regulates circadian rhythms. After activating gene transcription, ARNTL-CLOCK complexes eventually lead to the production of proteins that inhibit their own activity, creating a cycle that repeats approximately every 24 hours.

Disruptions in the function of ARNTL transcription factors have been linked to various circadian rhythm disorders and other health conditions, including sleep disorders, mood disorders, and cancer.

I believe there may be some confusion in your question as "caves" are not a medical term. A cave is a natural underground space that is large enough for a person to enter and can form in a variety of ways, such as the dissolution of limestone by acidic groundwater or the collapse of a volcanic tube. If you have any questions about geology or speleology (the study of caves), I would be happy to try to help answer those!

Cryptochromes are a type of photoreceptor protein found in plants and animals, including humans. They play a crucial role in regulating various biological processes such as circadian rhythms (the internal "body clock" that regulates sleep-wake cycles), DNA repair, and magnetoreception (the ability to perceive magnetic fields).

In humans, cryptochromes are primarily expressed in the retina of the eye and in various tissues throughout the body. They contain a light-sensitive cofactor called flavin adenine dinucleotide (FAD) that allows them to absorb blue light and convert it into chemical signals. These signals then interact with other proteins and signaling pathways to regulate gene expression and cellular responses.

In plants, cryptochromes are involved in the regulation of growth and development, including seed germination, stem elongation, and flowering time. They also play a role in the plant's ability to sense and respond to changes in light quality and duration, which is important for optimizing photosynthesis and survival.

Overall, cryptochromes are an essential component of many biological processes and have been the subject of extensive research in recent years due to their potential roles in human health and disease.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

Photoperiod is a term used in chronobiology, which is the study of biological rhythms and their synchronization with environmental cycles. In medicine, photoperiod specifically refers to the duration of light and darkness in a 24-hour period, which can significantly impact various physiological processes in living organisms, including humans.

In human medicine, photoperiod is often considered in relation to circadian rhythms, which are internal biological clocks that regulate several functions such as sleep-wake cycles, hormone secretion, and metabolism. The length of the photoperiod can influence these rhythms and contribute to the development or management of certain medical conditions, like mood disorders, sleep disturbances, and metabolic disorders.

For instance, exposure to natural daylight or artificial light sources with specific intensities and wavelengths during particular times of the day can help regulate circadian rhythms and improve overall health. Conversely, disruptions in the photoperiod due to factors like shift work, jet lag, or artificial lighting can lead to desynchronization of circadian rhythms and related health issues.

Flavoproteins are a type of protein molecule that contain noncovalently bound flavin mononucleotide (FMN) or flavin adenine dinucleotide (FAD) as cofactors. These flavin cofactors play a crucial role in redox reactions, acting as electron carriers in various metabolic pathways such as cellular respiration and oxidative phosphorylation. Flavoproteins are involved in several biological processes, including the breakdown of fatty acids, amino acids, and carbohydrates, as well as the synthesis of steroids and other lipids. They can also function as enzymes that catalyze various redox reactions, such as oxidases, dehydrogenases, and reductases. Flavoproteins are widely distributed in nature and found in many organisms, from bacteria to humans.

Circadian rhythm signaling peptides and proteins are molecules that play a crucial role in the regulation of circadian rhythms, which are physical, mental, and behavioral changes that follow a daily cycle. These rhythms are driven by the body's internal clock, which is located in the suprachiasmatic nucleus (SCN) of the hypothalamus.

The circadian rhythm is regulated by a complex network of signaling pathways involving both peptides and proteins. These molecules help to coordinate various physiological processes, such as sleep-wake cycles, hormone release, metabolism, and body temperature, with the external environment.

Some examples of circadian rhythm signaling peptides and proteins include:

1. PERIOD (PER) proteins: These are a family of proteins that play a central role in the regulation of the circadian clock. They form complexes with other clock proteins, such as CRYPTOCHROME (CRY) proteins, to inhibit the activity of transcription factors that drive the expression of clock genes.
2. CLOCK and BMAL1: These are transcription factors that bind to DNA and promote the expression of clock genes, including PER and CRY. They form a heterodimer that binds to specific DNA sequences called E-boxes to activate gene transcription.
3. REV-ERBα and RORα: These are nuclear receptors that regulate the expression of BMAL1 and other clock genes. REV-ERBα inhibits the expression of BMAL1, while RORα activates it.
4. Melatonin: This is a hormone produced by the pineal gland that helps to regulate sleep-wake cycles. Its production is controlled by light exposure and is highest at night.
5. Cortisol: This is a steroid hormone produced by the adrenal gland that helps to regulate metabolism, immune function, and stress response. Its levels are highest in the morning and decrease throughout the day.

Overall, circadian rhythm signaling peptides and proteins play a critical role in maintaining the proper functioning of various physiological processes, including sleep-wake cycles, metabolism, and immune function. Dysregulation of these pathways has been linked to several diseases, including cancer, diabetes, and cardiovascular disease.

Melatonin is a hormone that is produced by the pineal gland in the brain. It helps regulate sleep-wake cycles and is often referred to as the "hormone of darkness" because its production is stimulated by darkness and inhibited by light. Melatonin plays a key role in synchronizing the circadian rhythm, the body's internal clock that regulates various biological processes over a 24-hour period.

Melatonin is primarily released at night, and its levels in the blood can rise and fall in response to changes in light and darkness in an individual's environment. Supplementing with melatonin has been found to be helpful in treating sleep disorders such as insomnia, jet lag, and delayed sleep phase syndrome. It may also have other benefits, including antioxidant properties and potential uses in the treatment of certain neurological conditions.

It is important to note that while melatonin supplements are available over-the-counter in many countries, they should still be used under the guidance of a healthcare professional, as their use can have potential side effects and interactions with other medications.

I am not aware of a medical definition for the term "darkness." In general, darkness refers to the absence of light. It is not a term that is commonly used in the medical field, and it does not have a specific clinical meaning. If you have a question about a specific medical term or concept, I would be happy to try to help you understand it.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

In the context of medicine, "periodicity" refers to the occurrence of events or phenomena at regular intervals or cycles. This term is often used in reference to recurring symptoms or diseases that have a pattern of appearing and disappearing over time. For example, some medical conditions like menstrual cycles, sleep-wake disorders, and certain infectious diseases exhibit periodicity. It's important to note that the duration and frequency of these cycles can vary depending on the specific condition or individual.

"Neurospora crassa" is not a medical term, but it is a scientific name used in the field of biology. It refers to a type of filamentous fungus that belongs to the phylum Ascomycota. This organism is commonly found in the environment and has been widely used as a model system for studying various biological processes, including genetics, cell biology, and molecular biology.

"Neurospora crassa" has a characteristic red pigment that makes it easy to identify, and it reproduces sexually through the formation of specialized structures called ascocarps or "fruiting bodies." The fungus undergoes meiosis inside these structures, resulting in the production of ascospores, which are haploid spores that can germinate and form new individuals.

The genome of "Neurospora crassa" was one of the first fungal genomes to be sequenced, and it has served as an important tool for understanding fundamental biological processes in eukaryotic cells. However, because it is not a medical term, there is no official medical definition for "Neurospora crassa."

Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.

'Gene expression regulation' refers to the processes that control whether, when, and where a particular gene is expressed, meaning the production of a specific protein or functional RNA encoded by that gene. This complex mechanism can be influenced by various factors such as transcription factors, chromatin remodeling, DNA methylation, non-coding RNAs, and post-transcriptional modifications, among others. Proper regulation of gene expression is crucial for normal cellular function, development, and maintaining homeostasis in living organisms. Dysregulation of gene expression can lead to various diseases, including cancer and genetic disorders.

Cell cycle proteins are a group of regulatory proteins that control the progression of the cell cycle, which is the series of events that take place in a eukaryotic cell leading to its division and duplication. These proteins can be classified into several categories based on their functions during different stages of the cell cycle.

The major groups of cell cycle proteins include:

1. Cyclin-dependent kinases (CDKs): CDKs are serine/threonine protein kinases that regulate key transitions in the cell cycle. They require binding to a regulatory subunit called cyclin to become active. Different CDK-cyclin complexes are activated at different stages of the cell cycle.
2. Cyclins: Cyclins are a family of regulatory proteins that bind and activate CDKs. Their levels fluctuate throughout the cell cycle, with specific cyclins expressed during particular phases. For example, cyclin D is important for the G1 to S phase transition, while cyclin B is required for the G2 to M phase transition.
3. CDK inhibitors (CKIs): CKIs are regulatory proteins that bind to and inhibit CDKs, thereby preventing their activation. CKIs can be divided into two main families: the INK4 family and the Cip/Kip family. INK4 family members specifically inhibit CDK4 and CDK6, while Cip/Kip family members inhibit a broader range of CDKs.
4. Anaphase-promoting complex/cyclosome (APC/C): APC/C is an E3 ubiquitin ligase that targets specific proteins for degradation by the 26S proteasome. During the cell cycle, APC/C regulates the metaphase to anaphase transition and the exit from mitosis by targeting securin and cyclin B for degradation.
5. Other regulatory proteins: Several other proteins play crucial roles in regulating the cell cycle, such as p53, a transcription factor that responds to DNA damage and arrests the cell cycle, and the polo-like kinases (PLKs), which are involved in various aspects of mitosis.

Overall, cell cycle proteins work together to ensure the proper progression of the cell cycle, maintain genomic stability, and prevent uncontrolled cell growth, which can lead to cancer.

Transcription factors are proteins that play a crucial role in regulating gene expression by controlling the transcription of DNA to messenger RNA (mRNA). They function by binding to specific DNA sequences, known as response elements, located in the promoter region or enhancer regions of target genes. This binding can either activate or repress the initiation of transcription, depending on the properties and interactions of the particular transcription factor. Transcription factors often act as part of a complex network of regulatory proteins that determine the precise spatiotemporal patterns of gene expression during development, differentiation, and homeostasis in an organism.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Aging is a complex, progressive and inevitable process of bodily changes over time, characterized by the accumulation of cellular damage and degenerative changes that eventually lead to increased vulnerability to disease and death. It involves various biological, genetic, environmental, and lifestyle factors that contribute to the decline in physical and mental functions. The medical field studies aging through the discipline of gerontology, which aims to understand the underlying mechanisms of aging and develop interventions to promote healthy aging and extend the human healthspan.

"Nuclear Receptor Subfamily 1, Group D, Member 1" is a gene that encodes for the estrogen receptor alpha (ER-α). ER-α is a type of nuclear receptor protein that binds to estrogen, a female sex hormone, and mediates various biological responses such as cell growth, differentiation, and reproduction. The gene is also known as "ESR1" in medical and scientific literature. Mutations in this gene have been associated with various types of cancer, particularly breast cancer.

According to the United States Food and Drug Administration (FDA), biological products are "products that are made from or contain a living organism or its derivatives, such as vaccines, blood and blood components, cells, genes, tissues, and proteins." These products can be composed of sugars, proteins, nucleic acids, or complex combinations of these substances, and they can come from many sources, including humans, animals, microorganisms, or plants.

Biological products are often used to diagnose, prevent, or treat a wide range of medical conditions, and they can be administered in various ways, such as through injection, inhalation, or topical application. Because biological products are derived from living organisms, their manufacturing processes can be complex and must be tightly controlled to ensure the safety, purity, and potency of the final product.

It's important to note that biological products are not the same as drugs, which are chemically synthesized compounds. While drugs are designed to interact with specific targets in the body, such as enzymes or receptors, biological products can have more complex and varied mechanisms of action, making them potentially more difficult to characterize and regulate.

Look up biological clock in Wiktionary, the free dictionary. Biological clock may refer to: Age and female fertility, decrease ... biological program that limits the lifespan of an individual Biological rhythms Internal clock, the timeframe sensed by the ... biological process that displays an oscillation about 24 hours, such as the human sleep-wake cycle (the "body clock") ... Epigenetic clock, a set of DNA sites whose methylation levels can be used to measure aging throughout the body Molecular clock ...
Hardin PE (2000). "From biological clock to biological rhythms". Genome Biology. 1 (4): REVIEWS1023. doi:10.1186/gb-2000-1-4- ... In constant darkness, ClockΔ19 mice heterozygous for the Clock mutant allele exhibit lengthened circadian periods, while Clock ... Neuronal PAS domain containing protein 2 (NPAS2, a CLOCK paralog) can substitute for CLOCK in these Clock-null mice. Mice with ... The CLOCK-BMAL dimer acts as a positive limb of a feedback loop. The binding of CLOCK-BMAL to an E-box promoter element ...
In general, biological aging clocks and biomarkers of aging are expected to find many uses in biological research since age is ... Accurate measures of biological age (biological aging clocks) could be useful for testing the validity of various theories of ... Among these clocks, the PhenoAge and GrimAge clocks stand out. PhenoAge is an epigenetic clock that takes chronological age ... Overall, biological clocks are expected to be useful for studying what causes aging and what can be done against it. However, ...
Chemical clock Chemical oscillator Cromie W (1999-07-15). "Human Biological Clock Set Back an Hour". Harvard Gazette. Retrieved ... or bacterial clocks. The plant clock does have a conceptual similarity to the animal clock in that it consists of a series of ... MacKenzie D. "Biological clock began ticking 2.5 billion years ago". New Scientist. Loudon AS (July 2012). "Circadian biology: ... The basic molecular mechanisms of the biological clock have been defined in vertebrate species, Drosophila melanogaster, plants ...
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. Bibcode:1999PNAS ... 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 (August 1999). "Biological clocks". Proceedings of the National Academy of Sciences of the United ... Vrille mRNA and protein product (VRI) oscillate predictably on a 24-hour timescale and interact with other circadian clock ... Ohno T, Onishi Y, Ishida N (March 2007). "The negative transcription factor E4BP4 is associated with circadian clock protein ... Blau J, Young MW (December 1999). "Cycling vrille expression is required for a functional Drosophila clock". Cell. 99 (6): 661- ...
Ishida N, Kaneko M, Allada R (August 1999). "Biological clocks". Proc. Natl. Acad. Sci. U.S.A. 96 (16): 8819-20. Bibcode: ... 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 ...
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 (see Complexity and Singularity (system ...
Urist, Jacoba (October 21, 2013). "Men Have Biological Clocks, Too". The Atlantic. Retrieved September 15, 2015. "A Social ...
Galileo project entry SEDS Biography At the dawn of chronobiology Biological Clocks - Garden Variety Experiments Clock Classics ... "Biological Clocks - Garden Variety Experiments". HHMI. Archived from the original on 10 June 2013. Retrieved 5 April 2011. de ... Despite Marchant's publication of de Mairan's work, which might have suggested the existence of endogenous biological clocks, ... However, de Mairan did not infer that heliotropes have internal clocks driving leaf rhythms, but rather that they were able "to ...
Urist, Jacoba (October 21, 2013). "Men Have Biological Clocks, Too". The Atlantic. Retrieved April 2, 2014. Comite, Florence; ...
Millar AJ (4 January 2002). "Biological clocks in Arabidopsis thaliana". New Phytologist. 141 (2): 175-197. doi:10.1046/j.1469- ... the two sides of the Drosophila circadian clock". Journal of Biological Rhythms. 27 (6): 433-42. doi:10.1177/0748730412463181. ... "Clk Clock [Drosophila melanogaster (fruit fly)] - Gene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2019-04-11. "FlyBase Allele ... Mapping and cloning of the gene indicates that it is the Drosophila homolog of the mouse gene CLOCK (mClock). The Jrk mutation ...
"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 ...
... then the subject may not have a functioning internal biological clock or may have a disruption in the clock's output. While ... due to the fact that biological clocks rarely follow an exactly 24-hour cycle. If data points shift to the left, the subject is ... Biological Timekeeping: Clocks, Rhythms and Behaviour. New Delhi: Springer India. pp. 3-22. doi:10.1007/978-81-322-3688-7_1. ... An actogram is a plot that shows rhythms in biological variables throughout the day. Traditionally, actograms describe phases ...
"Biological clocks 'beat quicker' in cities". BBC. 5 June 2013. Retrieved 5 June 2013. Wilford, John Noble (5 June 2013). "Palm- ... The clock's measurements could form a new basis for global time standards, replacing the present generation of atomic clocks.[ ... 10 July French scientists construct an ultra-precise optical lattice clock that misses only one second in 300 million years. ... Following a large-scale genome study, researchers identify some of the biological roots of migraine, a chronic neurological ...
The Biological Clock. Two Views. Academic Press. 1970. Frank A. Brown Jr. The "Clocks" Timing Biological Rhythms: Recent ... Brown envisioned the biological clock as being a duality in which an internal responder to subtle information from the ... Cole, Lamont C. Biological Clock in the Unicorn. Science, Volume 125, Issue 3253, pp. 874-876. 1957 Heusner, A. 1965. "Sources ... The Biological Clock Phenomenon: Exogenous Timing Hypothesis. J. interdiscipl. Cycle Res., Vol. 14, number 2, pp. 137·162. Webb ...
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 ...
"Biological clocks: riding the tides." (2015) Journal of Biological Rhythms. "Access to Electric Light Is Associated with ... "Biological clocks and rhythms in intertidal crustaceans." (2013) Proceedings of the Royal Society B: Biological Sciences. " ... De la Iglesia is also president of the Society for Research on Biological Rhythms, an organization dedicated to promoting ... His thesis work aimed to understand the neuroanatomy of the master circadian clock of mammals - the suprachiasmatic nucleus ( ...
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. Tim Whitaker (15 ...
Biological clocks and circadian timing in cells". EMBO Reports. 6 Spec No (Suppl 1): S9-13. doi:10.1038/sj.embor.7400424. PMC ... In 2005, Tei, G. Lundkvist, Y. Kwak, E. Davis, and G. Block proposed that the molecular clock was linked to neurons' membrane ... In 2000, using their rodent model, they discovered the existence of circadian clocks in peripheral organs of mammals. This ... In 2016, a research team that included Tei discovered that clock genes, most specifically Bmal1 and Per1, are rhythmically ...
Lewis A (1999). Melatonin and the Biological Clock. McGraw-Hill. p. 23. ISBN 978-0-87983-734-1. "Melatonin - Special Subjects ... Nearly 70% of biological damage caused by ionizing radiation is estimated to be attributable to the creation of free radicals, ... Melatonin acts as an agonist of the melatonin MT1 and MT2 receptors, the biological targets of endogenous melatonin. It is ... Melatonin acts as an agonist of the melatonin MT1 and MT2 receptors, the biological targets of endogenous melatonin. Endogenous ...
clock". J. Exp. Biol. 97: 121-136. doi:10.1242/jeb.97.1.121. PMID 7201003. Dunlap, J.; Hastings, J.W. (1981). "The biological ... 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 ... Wilson, T. and Hastings, J.W. (1970) Chemical and biological aspects of singlet excited molecular oxygen. Photophysiology (A.C ...
Istvan, Zoltan (January 14, 2019). "Transhumanist science will free women from their biological clocks". Quartz. "The Language ...
They are genetic experiments with their biological clocks stopped. They encounter Toothpick, a companion cyber from the days ...
This regular oscillation is attributed to the maintenance of biological clock NADH activity of ENOX2 has been shown to be ... 2002). "Biochemical basis for the biological clock". Biochemistry. 41 (40): 11941-5. doi:10.1021/bi020392h. PMID 12356293. ... "Biochemical basis for the biological clock". Biochemistry. 41 (40): 11941-11945. doi:10.1021/bi020392h. ISSN 0006-2960. PMID ...
This discovery provided a tool for other scientists to perform research on biological clocks and was an important early ... "Gene Mutation Upsets Mammalian Biological Clock". Howard Hughes Medical Institute. April 21, 2000. Fish KJ, Cegielska A, Getman ... Harms E, Young MW, Saez L (2003). "CK1 and GSK3 in the Drosophila and Mammalian Circadian Clock". Molecular Clocks and Light ... role to mediate CLOCK phosphorylation and repress CLOCK-dependent transcription within the Drosophila circadian clock". ...
Ingle, Roisin (15 September 2007). "Tick-tock goes the biological clock". Irish Times (subscription required). Archived from ...
Due to the highly conserved nature of biological clocks, clock mechanisms have evolved relatively few times and are similar ... This form of communication may prove to be an adaptive feature of biological clocks and enable beneficial responses to changes ... Dunlap, Jay C.; Loros, Jennifer J. (2017-05-19). "Making Time: Conservation of Biological Clocks from Fungi to Animals". ... Dunlap is also interested in the interaction between biological clocks and metabolic processes. While circadian rhythms govern ...
At the doctor's, Ella explains her trepidations about childbirth and her wish that her biological clock would kick in. Dr. ... Clock on Hulu Clock at IMDb (Articles with short description, Short description is different from Wikidata, Use mdy dates from ... "Clock". Metacritic. Fandom, Inc. Retrieved August 24, 2023. Croot, James (May 3, 2023). "Clock: Disney+ has just delivered one ... Clock had its world premiere at the Overlook Film Festival in New Orleans on March 31, 2023. The film was released on April 28 ...
Look up biological clock in Wiktionary, the free dictionary. Biological clock may refer to: Age and female fertility, decrease ... biological program that limits the lifespan of an individual Biological rhythms Internal clock, the timeframe sensed by the ... biological process that displays an oscillation about 24 hours, such as the human sleep-wake cycle (the "body clock") ... Epigenetic clock, a set of DNA sites whose methylation levels can be used to measure aging throughout the body Molecular clock ...
... helps link the biological clock to the activity of pacemaker neurons. But Ir does not function as a simple output of the clock- ... "This process helps explain how our biological clocks keep such amazingly good time," said Justin Blau, an associate professor ... Biologists from New York University have uncovered new ways our biological clocks neurons use electrical activity to help keep ... NYU biologists have uncovered new ways our biological clocks neurons use electrical activity to help keep behavioral rhythms ...
... everyones 24-hour biological clock, Hebrew University of Jerusalem researchers have shown. ... everyones 24-hour biological clock, Hebrew University of Jerusalem researchers have shown. The biological clock regulates the ... but also by disrupting the phases and daily rhythm of clock genes. They contend also that high fat-induced changes in the clock ... in their experiments with laboratory mice that there is a cause-and-effect relation between diet and biological clock imbalance ...
... "clock genes" that drive their internal biological clocks showed that their social environment strongly affected their behavior. ... Research: Bees can reschedule biological clocks 0 Comments. Print. E-mail Xinhua, October 14, 2010 Adjust font size: ... seem to be able to reschedule their biological clocks without many troubles. ... "This flexibility in the bees clock is striking, given that humans and most other animals studied cannot sustain long periods ...
... researchers from University of California Los Angeles have developed a biological clock that may, for the first time, estimate ... Scientists Reveal New Biological Clock That Measures Aging Chicago Tribune. *Breasts age faster than other parts of a womans ... Using that data to build a statistical model of a biological clock that correlated methylation with chronological age, the ... researchers from University of California Los Angeles have developed a biological clock that may, for the first time, estimate ...
... the genes that set the biological clock. An implication of the finding is that cocaine addiction could be viewed and treated as ... University Of Virginia Researchers Link Cocaine Addiction Responses To Biological Clock Genes. Date:. August 13, 1999. Source: ... This indicates that certain circadian genes not only play a critical role in regulating the biological clock, but they may also ... 1999, August 13). University Of Virginia Researchers Link Cocaine Addiction Responses To Biological Clock Genes. ScienceDaily. ...
... of American scientists was awarded the Nobel Prize in physiology or medicine for revealing the mechanisms of the cellular clock ... that regulates biological changes in complex organisms across a 24-hour span. ... 3 Americans win Nobel Prize in medicine for uncovering the science behind our biological clocks ×. ... "were able to peek inside our biological clock and elucidate its inner workings." ...
That is, if your biological clock genes work the same way as those of a fruit fly. And they probably do. ... That is, if your "biological clock" genes work the same way as those of a fruit fly. And they probably do. Share:. Facebook ... Biological clock could be a key to better health, longer life. Date:. March 2, 2010. Source:. Oregon State University. Summary ... Biological clock could be a key to better health, longer life." ScienceDaily. www.sciencedaily.com. /. releases. /. 2010. /. ...
Smokings Effect on Our Biological Clock August 10, 2023 - What Makes Us Tick: Smokings Effect on Our Biological Clock ... "How will climate change affect our circadian clock? What other diseases are regulated by molecular clock molecules, and how ... "The molecular clocks purpose is to prepare your body for expected changes in the environment, like the times for activity, ... In a recent study, Rahman and team discovered how a specific clock molecule, called REV-ERBα, contributes to pulmonary fibrosis ...
Early menopause halted by resetting biological clock. Women who experience menopause early may be given the chance to have ...
biological clock meaning Blogs, Comments and Archive News on Economictimes.com ... biological clock meaning Latest Breaking News, Pictures, Videos, and Special Reports from The Economic Times. ... How your biological clock affects your health - all based on time of day. There is ample evidence that your biological clock is ... From the moment we wake up, our bodies have a biological clock that drives us to go back to sleep later in the day. ...
... biological clock that women recognize innately, and act on accordingly? New research casts some doubt on that. ... Is there a biological clock that women recognize innately, and act on accordingly? New research casts some doubt on that.. ... The notion of a biological clock in women arises from the fact that immature egg cells- oocytes - progressively decline in ...
But the idea of the biological clock is a recent invention. It first appeared in the late 1970s. "The Clock Is Ticking for the ... Yet, if we examine where the term came from, and how it came to be used, it becomes clear that the idea of the biological clock ... Biological clocks are certainly related to birth control, and I cant say Id ever thought about birth control for military ... Laurie and Debbies blogAngela Hovak Johnson, biological clock, birth control, Body Impolitic, colorism, Denise Oliver Velez, ...
This suggests an alteration of the circadian system per se that could in turn affect the expression of biological rhythms. In ... Age-related effects on the biological clock and its behavioral output in a primate Chronobiol Int. 2006;23(1-2):451-60. doi: ... two major peptides of the biological clock. Compared to adult animals, aged mouse lemurs showed a significant increase in ... This suggests an alteration of the circadian system per se that could in turn affect the expression of biological rhythms. In ...
... revistapesquisa.fapesp.br/en/biological-clock-of-plants-benefits-agriculture/ target=_blank>original here</a>.</ ...
Daniel Forger and Charles Peskin explain their mathematical model of the biological clock that replicates the hundreds of clock ... Researchers Simulate Biological Clock. By Will Parker on January 17, 2005 in News ... Biological circadian clocks time daily events with remarkable accuracy - often within seconds each day. However, understanding ... "Without the rapidity of molecular interactions within these cells, the precision of the biological clock would be lost. It is ...
... because their internal clocks operate on a 20-hour cycle instead of being synchronized with the 24-hour cycle of day and night. ... 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 ... mechanism explains how mutations shorten biological clocks. ... A new study explains how mutations in either CK1 or PERIOD can throw off the timing of biological clocks in animals from fruit ...
Men Who Wait to Have Kids Face a Ticking Biological Clock. Like women, a new study shows that mans age is a factor in the ... Your Biological Clock: Planning to Get Pregnant. Dealing with your body and your marriage gets into the picture when youre ... More Women Freeze Eggs to Freeze Biological Clock, says Study. Women have the option to freeze their eggs as a way to preserve ... For many aspiring parents planning to get pregnant, the persistent ticking of a biological clock does not always fall in line ...
Working overtime disturbs biological clock, say researchers. July. 11, 2018 08:17. [email protected]. People who work outside ... "Working overtime for three days is enough to destroy metabolism if the biological clock in the brain and digestive system is ... "Working overtime for three days is enough to destroy metabolism if the biological clock in the brain and digestive system is ... Working overtime disturbs biological clock, say researchers. Posted July. 11, 2018 08:17, ...
... constantly tortured by the ticking clock inside the Crocodiles belly on their way to destroy Neverland. He… ... and the Crocodile is my uterus and its ticking biological clock. I can hear that clock no matter how fast I run, and someday it ... And as my friends continue to get married and have babies, my biological clock keeps ticking louder and louder. ... Listen, biological clock. I hear you, but YOU HAVE GOT TO CHILL. ... if he hadnt swallowed that alarm clock. But now, when hes ...
Using a recently developed biomarker of aging known as an epigenetic clock, UCLA researchers working closely with a German team ... Horvath used the clock to measure the biological age of several tissues, and it proved accurate in matching biological to ... Using a novel biological clock, UCLA researchers find that obesity accelerates aging of the liver ... The epigenetic clock, which Horvath developed last year, uses a previously unknown time-keeping mechanism in the body to ...
Know the facts about your own biological clock and your particular ovarian reserve. Call to schedule a consult today. ... Beating Your Biological Clock - How It Works / Beating Your Biological Clock: Antrical Follicle Studies ... Such information would be of great help to young patients, who could relax somewhat about their biological clock if they knew ... Beating Your Biological Clock. Click Here to download Beating Your Biological Clock in PDF format. ...
10/21/2013 - Scientists Discover New Biological Clock With Age-Measuring Potential October 21, 2013. /in Longevity News 2013 / ... A team of scientists from UCLA have discovered a new biological clock with the potential to measure the age of human tissue. ... Scientists Discover New Biological Clock With Age-Measuring Potential. ...
... in vitro fertilization and third-party reproduction have made us rethink the biological clock concept. Recently, the successful ... have a biological fertility clock.". LaLiberte is referring to medical studies highlighting scientific evidence of a possible " ... in vitro fertilization and third-party reproduction have made us rethink the biological clock concept. Recently, the successful ...
Biological Clock Disruptions Sound Alzheimers Alarm. July 27, 2023• By Josh Barney, [email protected] Josh Barney, jdb9a@ ... While our biological clocks normally take cues from light, this adjustment happens gradually, as the body needs time to adapt. ... The new insights into the disruptions of the biological clock seen in Alzheimers could have important potential both for the ... Ferris and her collaborators used a mouse model of Alzheimers to better understand what happens to the biological clock in ...
The Conboy research lab has outlined the problems with existing machine learning-based clocks and created a new clock based on ... the Conboy research lab has outlined the problems with existing machine learning-based clocks and created a new […] ... an artificial intelligence algorithm that powers the majority of biological clocks, including the Horvath biological clock [1 ... This work shifts the dominant paradigm of what is biological age, uncovers that it is not an evenly "ticking clock" or a ...
... Copertaro A.. Writing - Original Draft ... The master clock of the biological rhythm, located in the suprachiasmatic nucleus of the anterior hypothalamus, synchronizes ... Working against the biological clock: A review for the occupational physician / Copertaro, A.; Bracci, M.. - In: INDUSTRIAL ... The master clock of the biological rhythm, located in the suprachiasmatic nucleus of the anterior hypothalamus, synchronizes ...
Women have a hard time deciding who they should see when they are having difficulty conceiving. Many women will first go to their Obstetrician/Gynecologist (OB/GYN). This is usually the first point of contact, when dealing with womens health issues. An OB/GYN cares for and treats the general population as well as a woman when she is pregnant. A Reproductive Endocrinologist, or Fertility Specialist, focuses exclusively on infertility. They work on evaluation, diagnosis, and treatment of all types of infertility. These specialists are best able to fully manage any fertility issues. For millions of women, the road to pregnancy can sometimes be difficult. This is why it is imperative to know when to see a Fertility Specialist and how they can help you.. When should you make an appointment with your Fertility Specialist?. If you are under 35 and have been unable to get pregnant after one year of unprotected intercourse or over 35 and have been unable to get pregnant after 6 months of unprotected ...
Jennifer Loros at Dartmouth Medical School in which she focused on molecular studies of the circadian biological clock in the ... Clocks Program Assistant. Department of Biology. 3258 TAMU. Texas A&M University. College Station, TX 77843. Phone: (979) 862- ... She serves as an Associate Editor of the Journal of Biological Rhythms, and has held several leadership positions in her field ... Her work currently focuses on understanding how the clock regulates mRNA transcription and translation, and how defects in the ...
Podcast 209: Turning Back Your Biological Clock with Bryan Johnson. February 16, 2023. ...

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