scholarly journals Biological Effects of Space Hypomagnetic Environment on Circadian Rhythm

2021 ◽  
Vol 12 ◽  
Author(s):  
Xunwen Xue ◽  
Yasser F. Ali ◽  
Wanrong Luo ◽  
Caorui Liu ◽  
Guangming Zhou ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Neurological Diseases ◽  
Biological Effects ◽  
Outer Space ◽  
Interdisciplinary Cooperation ◽  
Hypomagnetic Field ◽  
Earth Magnetic Field ◽  
Living Organisms ◽  
Interplanetary Missions

The intrinsic earth magnetic field (geomagnetic field, GMF) provides an essential environmental condition for most living organisms to adapt the solar cycle by rhythmically synchronizing physiological and behavioral processes. However, hypomagnetic field (HMF) of outer space, the Moon, and the Mars differs much from GMF, which poses a critical problem to astronauts during long-term interplanetary missions. Multiple experimental works have been devoted to the HMF effects on circadian rhythm and found that HMF perturbs circadian rhythms and profoundly contributes to health problems such as sleep disorders, altered metabolic as well as neurological diseases. By systemizing the latest progress on interdisciplinary cooperation between magnetobiology and chronobiology, this review sheds light on the health effects of HMF on circadian rhythms by elaborating the underlying circadian clock machinery and molecular processes.

scholarly journals Dopamine: a modulator of circadian rhythms/biological clock

2021 ◽  
Vol 8 (2) ◽  
pp. 316
Author(s):  
Ravi Kant ◽  
Mahendra K. Meena ◽  
Monika Pathania
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Seasonal Affective Disorder ◽  
Clock Genes ◽  
Biological Clock ◽  
Bipolar Disorders ◽  
Vital Role ◽  
Brain Areas ◽  
Light Levels ◽  
Living Organisms

Circadian rhythm describes the physical, psychological, and behavioural patterns of living organisms that respond to day and night light levels. The important bodily functions like hunger, sleep, gastrointestinal motility, mood, coordination, body temperature, gene transcription, sensory perceptions, sleep-wake cycles and hormone release etc are influenced by circadian rhythm. Abnormal circadian rhythm may result obesity, depression, diabetes, seasonal affective disorder, bipolar disorders and various sleep disorders. The neuromodulator dopamine, originate from small groups of neurons in the mesencephalon (the ventral tegmental area, the substantia nigra) and in the diencephalon. In the retina, olfactory bulb, striatum, midbrain, and hypothalamus, it has been shown to have that dopamine shows circadian like activities, where it regulates, clock genes in some of these areas. Thus, it is likely that dopamine is essential to mechanisms that maintain proper rhythmicity of these five brain areas. Dopamine receptors are located centrally and peripherally. Growing evidence that dopamine is involved in regulating circadian rhythms, either directly or indirectly, in the brain areas through various pathways and dopaminergic receptor groups centrally and peripherally, and plays vital role.  

scholarly journals Chirality Matters: Biological Activity of Optically Pure Silybin and Its Congeners

2021 ◽  
Vol 22 (15) ◽  
pp. 7885
Author(s):  
Vladimír Křen
Keyword(s):  
Neurological Diseases ◽  
Biological Effects ◽  
Drug Metabolizing Enzymes ◽  
Metabolizing Enzymes ◽  
Biological Targets ◽  
Molecular Effects ◽  
Anisotropic Systems ◽  
Specific Activities ◽  
Optically Pure

This review focuses on the specific biological effects of optically pure silymarin flavo-nolignans, mainly silybins A and B, isosilybins A and B, silychristins A and B, and their 2,3-dehydro derivatives. The chirality of these flavonolignans is also discussed in terms of their analysis, preparative separation and chemical reactions. We demonstrated the specific activities of the respective diastereomers of flavonolignans and also the enantiomers of their 2,3-dehydro derivatives in the 3D anisotropic systems typically represented by biological systems. In vivo, silymarin flavonolignans do not act as redox antioxidants, but they play a role as specific ligands of biological targets, according to the “lock-and-key” concept. Estrogenic, antidiabetic, anticancer, antiviral, and antiparasitic effects have been demonstrated in optically pure flavonolignans. Potential application of pure flavonolignans has also been shown in cardiovascular and neurological diseases. Inhibition of drug-metabolizing enzymes and modulation of multidrug resistance activity by these compounds are discussed in detail. The future of “silymarin applications” lies in the use of optically pure components that can be applied directly or used as valuable lead structures, and in the exploration of their true molecular effects.

scholarly journals Time-restricted feeding regulates circadian rhythm of murine uterine clock

2021 ◽  
Author(s):  
Takashi Hosono ◽  
Masanori Ono ◽  
Takiko Daikoku ◽  
Michihiro Mieda ◽  
Satoshi Nomura ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Protein Expression ◽  
Western Blot ◽  
Active Phase ◽  
Active Period ◽  
Restricted Feeding ◽  
Group Iii ◽  
Breakfast Skipping ◽  
Group I

Abstract Background Skipping breakfast is associated with dysmenorrhea in young women. This suggests that the delay of food intake in the active phase impairs uterine functions by interfering with circadian rhythms. Objective To examine the relationship between the delay of feeding and uterine circadian rhythms, we investigated the effects of the first meal occasion in the active phase on the uterine clock. Methods Zeitgeber time (ZT) was defined as ZT 0 (8:45) with lights on and ZT 12 (20:45) with lights off. Young female mice (8 weeks of age) were divided into 3 groups: group I (ad-libitum feeding), group II (time-restricted feeding during ZT12–16, initial 4 hours of the active period), and group III (time-restricted feeding during ZT20–24, last 4 hours of the active period, a breakfast-skipping model). After two weeks of dietary restriction, mice in each group were sacrificed at 4-hour intervals and the expression profiles of uterine clock genes, Bmal1, Per1, Per2, and Cry1, were examined. Results qPCR and Western blot analyses demonstrated synchronized circadian clock gene expression within the uterus. Immunohistochemical analysis confirmed that Bmal1 protein expression was synchronized among the endometrium and myometrium. In groups I and II, mRNA expression of Bmal1 was elevated after ZT12 at the start of the active phase. In contrast, Bmal1 expression was elevated just after ZT20 in group III, showing that the uterine clock rhythm had shifted 8 hours backward. The changes in Bmal1 protein expression were confirmed by Western blot analysis. Conclusion This study is the first to indicate that time-restricted feeding regulates a circadian rhythm of the uterine clock that is synchronized throughout the uterine body. These findings suggest that the uterine clock system is a new candidate to explain the etiology of breakfast skipping-induced uterine dysfunction.

scholarly journals Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

2021 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Andy W. C. Man ◽  
Huige Li ◽  
Ning Xia
Keyword(s):  
Circadian Rhythm ◽  
Cardiovascular Diseases ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Therapeutic Target ◽  
Environmental Changes ◽  
Clock Genes ◽  
Vascular System ◽  
Peripheral Tissues ◽  
Inflammatory Processes

Every organism has an intrinsic biological rhythm that orchestrates biological processes in adjusting to daily environmental changes. Circadian rhythms are maintained by networks of molecular clocks throughout the core and peripheral tissues, including immune cells, blood vessels, and perivascular adipose tissues. Recent findings have suggested strong correlations between the circadian clock and cardiovascular diseases. Desynchronization between the circadian rhythm and body metabolism contributes to the development of cardiovascular diseases including arteriosclerosis and thrombosis. Circadian rhythms are involved in controlling inflammatory processes and metabolisms, which can influence the pathology of arteriosclerosis and thrombosis. Circadian clock genes are critical in maintaining the robust relationship between diurnal variation and the cardiovascular system. The circadian machinery in the vascular system may be a novel therapeutic target for the prevention and treatment of cardiovascular diseases. The research on circadian rhythms in cardiovascular diseases is still progressing. In this review, we briefly summarize recent studies on circadian rhythms and cardiovascular homeostasis, focusing on the circadian control of inflammatory processes and metabolisms. Based on the recent findings, we discuss the potential target molecules for future therapeutic strategies against cardiovascular diseases by targeting the circadian clock.

Etudes comparées des rythmes circadiens et reflet actimétrique du sommeil de sportifs et de sédentaires en poste régulier de nuit

2003 ◽  
Vol 28 (6) ◽  
pp. 831-887 ◽  
Author(s):  
Benoît Mauvieux ◽  
Laurent Gouthière ◽  
Bruno Sesboüe ◽  
Damien Davenne
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Sleep Quality ◽  
Shift Work ◽  
Physical Training ◽  
Night Shift ◽  
Circadian Variation ◽  
Night Work ◽  
Sedentary Subjects

The aim of this study was to show the resistance and persistence of the circadian rhythm of temperature (T°) and the sleep quality of athletic subjects and sedentary subjects engaged in night work, and attempt to explain the mechanisms that influence these differences. The effects of night work on biological rhythms have been studied extensively in the past few years. The contradictory situations for the night workers irrefutably affect their biological systems. Individuals with high amplitudes in their circadian rhythms have been found to be more tolerant to shift work and this results in a greater stability of circadian rhythms. This seems beneficial in coping with frequent rhythm disturbances. The physical training program seems to improve several mechanisms of the human biological system: amplitudes of circadian rhythms were increased and the circadian rhythm period was more resistant to an environment extreme (night work, shift work, sleep deprivation, or jet lag). To test this hypothesis, athletes and sedentary subjects who were engaged in regular night work were selected in the PSA Peugeot Citroën Automobiles Group in French Normandy country. The circadian rhythm of the T° for both groups was studied with a specific methodology and with extensive spectral analysis, especially the spectral elliptic inverse method. Study models of the rhythm of the T° were determined and the characteristic parameters were exposed. A complementary actigraphic study showed the physical training program's effects on the sleep quality. The results revealed a large stability in the rhythm of circadian variation of T° for the athletes: the amplitude was still large but for the sedentary subjects the amplitude of the T° decreased and it was difficult to adjust a period on the rhythm of T°. The stability and persistent quality of the athletes' circadian rhythm was confirmed. We observed that the actigraphic sleep was greater for athletes than for sedentary subjects, and the acrophase time for the athletes was later than for the sedentary subjects during the night shift. Key words: circadian rhythm of temperature, actimetry, sleep quality, exercise, night work, methodology of rhythms analysis

scholarly journals Survival is reduced when endogenous period deviates from 24 h in a non-human primate, supporting the circadian resonance theory

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Clara Hozer ◽  
Martine Perret ◽  
Samuel Pavard ◽  
Fabien Pifferi
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Microcebus Murinus ◽  
Circadian Period ◽  
Biological Functions ◽  
Resonance Theory ◽  
Aging Research ◽  
Mouse Lemurs ◽  
Living Organisms ◽  
Human Primate

Abstract Circadian rhythms are ubiquitous attributes across living organisms and allow the coordination of internal biological functions with optimal phases of the environment, suggesting a significant adaptive advantage. The endogenous period called tau lies close to 24 h and is thought to be implicated in individuals’ fitness: according to the circadian resonance theory, fitness is reduced when tau gets far from 24 h. In this study, we measured the endogenous period of 142 mouse lemurs (Microcebus murinus), and analyzed how it is related to their survival. We found different effects according to sex and season. No impact of tau on mortality was found in females. However, in males, the deviation of tau from 24 h substantially correlates with an increase in mortality, particularly during the inactive season (winter). These results, comparable to other observations in mice or drosophila, show that captive gray mouse lemurs enjoy better fitness when their circadian period closely matches the environmental periodicity. In addition to their deep implications in health and aging research, these results raise further ecological and evolutionary issues regarding the relationships between fitness and circadian clock.

scholarly journals Uncovering the mystery of opposite circadian rhythms between mouse and human leukocytes in humanized mice

Blood ◽  
2017 ◽  
Vol 130 (18) ◽  
pp. 1995-2005 ◽  
Author(s):  
Yue Zhao ◽  
Min Liu ◽  
Xue Ying Chan ◽  
Sue Yee Tan ◽  
Sharrada Subramaniam ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Molecular Clock ◽  
Humanized Mice ◽  
Human Leukocytes ◽  
Clock Network ◽  
Key Points ◽  
Human And Mouse

Key Points Human circulating leukocytes in humanized mice reproduce similar circadian oscillations as seen in humans. A novel molecular clock network exhibiting opposite effects on regulating human and mouse leukocyte circadian rhythm is discovered.

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 Multi-Modal Regulation of Circadian Physiology by Interactive Features of Biological Clocks

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Yool Lee ◽  
Jonathan P. Wisor
Keyword(s):  
Circadian Clock ◽  
Neurological Diseases ◽  
Night Shift ◽  
Hormone Secretion ◽  
Local Environment ◽  
Biological Clocks ◽  
Tightly Coupled ◽  
Peripheral Clocks ◽  
Living Organisms ◽  
Circadian Physiology

The circadian clock is a fundamental biological timing mechanism that generates nearly 24 h rhythms of physiology and behaviors, including sleep/wake cycles, hormone secretion, and metabolism. Evolutionarily, the endogenous clock is thought to confer living organisms, including humans, with survival benefits by adapting internal rhythms to the day and night cycles of the local environment. Mirroring the evolutionary fitness bestowed by the circadian clock, daily mismatches between the internal body clock and environmental cycles, such as irregular work (e.g., night shift work) and life schedules (e.g., jet lag, mistimed eating), have been recognized to increase the risk of cardiac, metabolic, and neurological diseases. Moreover, increasing numbers of studies with cellular and animal models have detected the presence of functional circadian oscillators at multiple levels, ranging from individual neurons and fibroblasts to brain and peripheral organs. These oscillators are tightly coupled to timely modulate cellular and bodily responses to physiological and metabolic cues. In this review, we will discuss the roles of central and peripheral clocks in physiology and diseases, highlighting the dynamic regulatory interactions between circadian timing systems and multiple metabolic factors.

scholarly journals Chronic Corticosterone Disrupts the Circadian Rhythm of CRH Expression and M6a RNA Methylation in the Chicken Hypothalamus

2021 ◽  
Author(s):  
Yang Yang ◽  
Wanwan Han ◽  
Aijia Zhang ◽  
Mindie Zhao ◽  
Wei Cong ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Chronic Stress ◽  
Hpa Axis ◽  
Clock Genes ◽  
Diurnal Fluctuation ◽  
Opposite Pattern ◽  
Rna Methylation ◽  
Diurnal Patterns ◽  
M6a Rna Methylation

Abstract Corticotropin-releasing hormone (CRH), the major secretagogue of the hypothalamic-pituitary-adrenal (HPA) axis, is intricately intertwined with the clock genes to regulate the circadian rhythm of various body functions. N6-methyladenosine (m6A) RNA methylation is involved in the regulation of circadian rhythm, yet it remains unknown whether CRH expression and m6A modification oscillate with the clock genes in chicken hypothalamus and how the circadian rhythms change under chronic stress. Here, we show that chronic exposure to corticosterone (CORT) eliminated the diurnal patterns of plasma CORT and melatonin levels in the chicken. The circadian rhythms of clock genes in hippocampus, hypothalamus and pituitary are all disturbed to different extent in CORT-treated chickens. The most striking changes occur in hypothalamus in which the diurnal fluctuation of CRH mRNA is flattened, together with mRNA of other feeding-related neuropeptides. Interestingly, hypothalamic m6A level oscillates in an opposite pattern to CRH mRNA, with lowest m6A level after midnight (ZT18) corresponding to the peak of CRH mRNA before dawn (ZT22). CORT diminished the circadian rhythm of m6A methylation with significantly increased level at night. Further site-specific m6A analysis on 3’UTR of CRH mRNA indicates that higher m6A on 3’UTR of CRH mRNA coincides with lower CRH mRNA at night (ZT18 and ZT22). Our results indicate that chronic stress disrupts the circadian rhythms of CRH expression in hypothalamus, leading to dysfunction of HPA axis in the chicken. RNA m6A modification is involved in the regulation of circadian rhythms in chicken hypothalamus under both basal and chronic stress conditions.

Sign in / Sign up

Export Citation Format

Share Document