1. Circadian rhythms

2017 ◽  
pp. 1-12
Author(s):  
Russell G. Foster ◽  
Leon Kreitzman
Keyword(s):  
Solar Cycle ◽  
Circadian Rhythms ◽  
Temperature Compensation ◽  
Environmental Temperature ◽  
Biological Processes ◽  
Vast Array ◽  
Physiological Processes ◽  
Almost All

‘Circadian rhythms: A 24-hour phenomenon’ explains the internally generated ‘clock’ that almost all living beings on Earth possess, which allows them to optimize a vast array of physiological processes and behaviour in advance of the varied demands of the daily solar cycle. Circadian rhythms are encoded in organisms’ genes, endogenously generated, and show near 24-hour rhythms in biological processes. They persist under constant conditions for several cycles, are entrained to the astronomical day via synchronizing zeitgebers, and show temperature compensation such that the period of the oscillation does not alter appreciably with changes in environmental temperature.

scholarly journals Effects of Substituents on Photophysical and CO-Photoreleasing Properties of 2,6-Substituted meso-Carboxy BODIPY Derivatives

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 238-255
Author(s):  
Esther M. Sánchez-Carnerero ◽  
Marina Russo ◽  
Andreas Jakob ◽  
Lucie Muchová ◽  
Libor Vítek ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Absorption Spectra ◽  
Wavelength Range ◽  
Toxic Effects ◽  
Biological Research ◽  
In Vitro Experiments ◽  
Vast Array ◽  
Physiological Processes ◽  
Photochemical Properties

Carbon monoxide (CO) is an endogenously produced signaling molecule involved in the control of a vast array of physiological processes. One of the strategies to administer therapeutic amounts of CO is the precise spatial and temporal control over its release from photoactivatable CO-releasing molecules (photoCORMs). Here we present the synthesis and photophysical and photochemical properties of a small library of meso-carboxy BODIPY derivatives bearing different substituents at positions 2 and 6. We show that the nature of substituents has a major impact on both their photophysics and the efficiency of CO photorelease. CO was found to be efficiently released from π-extended 2,6-arylethynyl BODIPY derivatives possessing absorption spectra shifted to a more biologically desirable wavelength range. Selected photoCORMs were subjected to in vitro experiments that did not reveal any serious toxic effects, suggesting their potential for further biological research.

Design of Ultrasonic Ranging Circuit Based on STC Microcontroller

2013 ◽  
Vol 722 ◽  
pp. 59-63
Author(s):  
Rui Luo ◽  
Zi Hong Zhang
Keyword(s):  
System Performance ◽  
Temperature Compensation ◽  
Measurement Accuracy ◽  
Environmental Temperature ◽  
Detection Distance ◽  
Compensation Circuit ◽  
High Measurement ◽  
Ultrasonic Ranging ◽  
Allowable Range ◽  
Market Promotion

In this paper, based on the 18B20 temperature compensation circuit for ultrasonic ranging circuit, can eliminate the influence of environmental temperature on ultrasonic velocity, this paper introduced the ultrasonic ranging system, the system includes ultrasonic transmitting circuit, receiving circuit and display circuit, the results of the experiment show that, the system detection distance can be up to 12M, the error is in the allowable range, the range finder the system performance is stable, high measurement accuracy, distance, has a certain practicality and market promotion value.

scholarly journals Drugs of Abuse Can Entrain Circadian Rhythms

2007 ◽  
Vol 7 ◽  
pp. 203-212 ◽  
Author(s):  
Ann E. K. Kosobud ◽  
Andrea G. Gillman ◽  
Joseph K. Leffel ◽  
Norman C. Pecoraro ◽  
G. V. Rebec ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Drug Metabolism ◽  
Suprachiasmatic Nucleus ◽  
Drugs Of Abuse ◽  
Social Cues ◽  
Dark Cycle ◽  
Drug Reward ◽  
Locomotor Stimulation ◽  
Almost All

Circadian rhythms prepare organisms for predictable events during the Earth's 24-h day. These rhythms are entrained by a variety of stimuli. Light is the most ubiquitous and best known zeitgeber, but a number of others have been identified, including food, social cues, locomotor activity, and, most recently drugs of abuse. Given the diversity of zeitgebers, it is probably not surprising that genes capable of clock functions are located throughout almost all organs and tissues. Recent evidence suggests that drugs of abuse can directly entrain some circadian rhythms. We have report here that entrainment by drugs of abuse is independent of the suprachiasmatic nucleus and the light/dark cycle, is not dependent on direct locomotor stimulation, and is shared by a variety of classes of drugs of abuse. We suggest that drug-entrained rhythms reflect variations in underlying neurophysiological states. This could be the basis for known daily variations in drug metabolism, tolerance, and sensitivity to drug reward. These rhythms could also take the form of daily periods of increased motivation to seek and take drugs, and thus contribute to abuse, addiction and relapse.

scholarly journals Interaction between photoperiod and variation in circadian rhythms in tomato

2022 ◽  
Author(s):  
Yanli Xiang ◽  
Thomas Sapir ◽  
Pauline Rouillard ◽  
Marina Ferrand ◽  
Jose M Jimenez-Gomez
Keyword(s):  
Seasonal Variation ◽  
Circadian Rhythms ◽  
Phase Shift ◽  
Circadian Clock ◽  
Environmental Changes ◽  
Circadian Clocks ◽  
Biological Processes ◽  
Near Isogenic Lines ◽  
Transcriptomic Profiling ◽  
Isogenic Lines

Many biological processes follow circadian rhythmicity and are controlled by the circadian clock. Predictable environmental changes such as seasonal variation in photoperiod can modulate circadian rhythms, allowing organisms to adjust to the time of the year. Modification of circadian clocks is especially relevant in crops to enhance their cultivability in specific regions by changing their sensibility to photoperiod. In tomato, the appearance of mutations in EMPFINDLICHER IM DUNKELROTEN LICHT 1 (EID1, Solyc09g075080) and NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED GENE 2 (LNK2, Solyc01g068560) during domestication delayed its circadian rhythms, and allowed its expansion outside its equatorial origin. Here we study how variation in circadian rhythms in tomato affects its perception of photoperiod. To do this, we create near isogenic lines carrying combinations of wild alleles of EID1 and LNK2 and perform transcriptomic profiling under two different photoperiods. We observe that EID1, but not LNK2, has a large effect on the tomato transcriptome and its response to photoperiod. This large effect of EID1 is likely a consequence of the global phase shift elicited by this gene in tomato's circadian rhythms.

scholarly journals Exercise mitigates sleep-loss-induced changes in glucose tolerance, mitochondrial function, sarcoplasmic protein synthesis, and circadian rhythms

2020 ◽  
Author(s):  
Nicholas J Saner ◽  
Matthew J-C Lee ◽  
Jujiao Kuang ◽  
Nathan W Pitchford ◽  
Gregory D Roach ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Circadian Rhythms ◽  
Glucose Tolerance ◽  
Mitochondrial Function ◽  
Sleep Loss ◽  
Physiological Processes ◽  
Sarcoplasmic Protein ◽  
Concomitant Reduction ◽  
High Intensity Interval ◽  
Inadequate Sleep

AbstractSleep loss has emerged as a risk factor for the development of impaired glucose tolerance. The mechanisms underpinning this observation are unknown; however, both mitochondrial dysfunction and circadian misalignment have been proposed. Given that exercise improves glucose tolerance, mitochondrial function, and alters circadian rhythms, we investigated whether exercise may counteract the effects induced by inadequate sleep. We report that sleeping 4 hours per night, for five nights, reduced glucose tolerance, with novel observations of associated reductions in mitochondrial function, sarcoplasmic protein synthesis, and measures of circadian rhythmicity; however, incorporating three sessions of high-intensity interval exercise (HIIE) during this period mitigates these effects. These data demonstrate, for the first time, a sleep loss-induced concomitant reduction in a range of physiological processes linked to metabolic function. These same effects are not observed when exercise is performed during a period of inadequate sleep, supporting the use of HIIE as an intervention to mitigate the detrimental physiological effects of sleep loss.

scholarly journals Ocular Autonomic Nervous System: An Update from Anatomy to Physiological Functions

Vision ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Feipeng Wu ◽  
Yin Zhao ◽  
Hong Zhang
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Neural Control ◽  
Entire Body ◽  
Physiological Functions ◽  
Autonomic Nervous ◽  
Parasympathetic Nerves ◽  
Physiological Processes ◽  
New Research ◽  
Almost All

The autonomic nervous system (ANS) confers neural control of the entire body, mainly through the sympathetic and parasympathetic nerves. Several studies have observed that the physiological functions of the eye (pupil size, lens accommodation, ocular circulation, and intraocular pressure regulation) are precisely regulated by the ANS. Almost all parts of the eye have autonomic innervation for the regulation of local homeostasis through synergy and antagonism. With the advent of new research methods, novel anatomical characteristics and numerous physiological processes have been elucidated. Herein, we summarize the anatomical and physiological functions of the ANS in the eye within the context of its intrinsic connections. This review provides novel insights into ocular studies.

scholarly journals RNA Deregulation in Amyotrophic Lateral Sclerosis: The Noncoding Perspective

2021 ◽  
Vol 22 (19) ◽  
pp. 10285
Author(s):  
Pietro Laneve ◽  
Paolo Tollis ◽  
Elisa Caffarelli
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Potential Role ◽  
Noncoding Rnas ◽  
Rna Metabolism ◽  
Biological Processes ◽  
Diagnostic Biomarkers ◽  
Defective Rna ◽  
Almost All ◽  
Lateral Sclerosis

RNA metabolism is central to cellular physiopathology. Almost all the molecular pathways underpinning biological processes are affected by the events governing the RNA life cycle, ranging from transcription to degradation. The deregulation of these processes contributes to the onset and progression of human diseases. In recent decades, considerable efforts have been devoted to the characterization of noncoding RNAs (ncRNAs) and to the study of their role in the homeostasis of the nervous system (NS), where they are highly enriched. Acting as major regulators of gene expression, ncRNAs orchestrate all the steps of the differentiation programs, participate in the mechanisms underlying neural functions, and are crucially implicated in the development of neuronal pathologies, among which are neurodegenerative diseases. This review aims to explore the link between ncRNA dysregulation and amyotrophic lateral sclerosis (ALS), the most frequent motoneuron (MN) disorder in adults. Notably, defective RNA metabolism is known to be largely associated with this pathology, which is often regarded as an RNA disease. We also discuss the potential role that these transcripts may play as diagnostic biomarkers and therapeutic targets.

scholarly journals The Expression and Function of Circadian Rhythm Genes in Hepatocellular Carcinoma

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yanan Jiang ◽  
Xiuyun Shen ◽  
Moyondafoluwa Blessing Fasae ◽  
Fengnan Zhi ◽  
Lu Chai ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Molecular Mechanisms ◽  
Therapeutic Targets ◽  
Pathogenic Mechanism ◽  
Research Progress ◽  
Biological Processes ◽  
And Function ◽  
Novel Therapeutic

Hepatocellular carcinoma (HCC) is among the most common and lethal form of cancer worldwide. However, its diagnosis and treatment are still dissatisfactory, due to limitations in the understanding of its pathogenic mechanism. Therefore, it is important to elucidate the molecular mechanisms and identify novel therapeutic targets for HCC. Circadian rhythm-related genes control a variety of biological processes. These genes play pivotal roles in the initiation and progression of HCC and are potential diagnostic markers and therapeutic targets. This review gives an update on the research progress of circadian rhythms, their effects on the initiation, progression, and prognosis of HCC, in a bid to provide new insights for the research and treatment of HCC.

scholarly journals Casein Kinase 1 Underlies Temperature Compensation of Circadian Rhythms in Human Red Blood Cells

2019 ◽  
Vol 34 (2) ◽  
pp. 144-153 ◽  
Author(s):  
Andrew D. Beale ◽  
Emily Kruchek ◽  
Stephen J. Kitcatt ◽  
Erin A. Henslee ◽  
Jack S.W. Parry ◽  
...  
Keyword(s):  
Gene Expression ◽  
Circadian Rhythms ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Temperature Compensation ◽  
Clock Gene ◽  
Cell Types ◽  
Casein Kinase ◽  
Casein Kinase 1 ◽  
Human Red Blood Cells

Temperature compensation and period determination by casein kinase 1 (CK1) are conserved features of eukaryotic circadian rhythms, whereas the clock gene transcription factors that facilitate daily gene expression rhythms differ between phylogenetic kingdoms. Human red blood cells (RBCs) exhibit temperature-compensated circadian rhythms, which, because RBCs lack nuclei, must occur in the absence of a circadian transcription-translation feedback loop. We tested whether period determination and temperature compensation are dependent on CKs in RBCs. As with nucleated cell types, broad-spectrum kinase inhibition with staurosporine lengthened the period of the RBC clock at 37°C, with more specific inhibition of CK1 and CK2 also eliciting robust changes in circadian period. Strikingly, inhibition of CK1 abolished temperature compensation and increased the Q10 for the period of oscillation in RBCs, similar to observations in nucleated cells. This indicates that CK1 activity is essential for circadian rhythms irrespective of the presence or absence of clock gene expression cycles.

scholarly journals Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae)

2020 ◽  
Vol 130 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Kentarou Matsumura ◽  
Masato S Abe ◽  
Manmohan D Sharma ◽  
David J Hosken ◽  
Taishi Yoshii ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Phenotypic Plasticity ◽  
Circadian Rhythms ◽  
Temperature Effects ◽  
Temperature Compensation ◽  
Biological Rhythms ◽  
Total Activity ◽  
Biological Clocks ◽  
Isofemale Lines ◽  
Free Running

Abstract Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype–sex–environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways.

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