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Genome Biology 2000The genetic and molecular analysis of circadian timekeeping mechanisms has accelerated as a result of the increasing volume of genomic markers and nucleotide sequence... (Review)
Review
The genetic and molecular analysis of circadian timekeeping mechanisms has accelerated as a result of the increasing volume of genomic markers and nucleotide sequence information. Completion of whole genome sequences and the use of differential gene expression technology will hasten the discovery of the clock output pathways that control diverse rhythmic phenomena.
Topics: Animals; Biological Clocks; Circadian Rhythm; Gene Expression Profiling; Models, Biological; RNA, Messenger; Signal Transduction
PubMed: 11178250
DOI: 10.1186/gb-2000-1-4-reviews1023 -
Molecular Biology Reports Jul 2023In the past decades, resveratrol has gained increasing attention due to its versatile and beneficial properties. This natural polyphenol, commonly present in the human... (Review)
Review
In the past decades, resveratrol has gained increasing attention due to its versatile and beneficial properties. This natural polyphenol, commonly present in the human diet, has been shown to induce SIRT1 and to modulate the circadian rhythm at the cellular and organismal levels. The circadian clock is a system regulating behavior and function of the human body, thus playing a crucial role in health maintenance. It is primarily entrained by light-dark cycles; however, other factors such as feeding-fasting, oxygen and temperature cycles play a significant role in its regulation. Chronic circadian misalignment can lead to numerous pathologies, including metabolic disorders, age-related diseases or cancer. Therefore, the use of resveratrol may be a valuable preventive and/or therapeutic strategy for these pathologies. This review summarizes studies that evaluated the modulatory effect of resveratrol on circadian oscillators by focusing on the potential and limitations of resveratrol in biological clock-related disorders.
Topics: Humans; Circadian Clocks; Resveratrol; Circadian Rhythm; Diet; Fasting
PubMed: 37231216
DOI: 10.1007/s11033-023-08513-2 -
Plant, Cell & Environment Mar 2006Life occurs in an ever-changing environment. Some of the most striking and predictable changes are the daily rhythms of light and temperature. To cope with these... (Review)
Review
Life occurs in an ever-changing environment. Some of the most striking and predictable changes are the daily rhythms of light and temperature. To cope with these rhythmic changes, plants use an endogenous circadian clock to adjust their growth and physiology to anticipate daily environmental changes. Most studies of circadian functions in plants have been performed under continuous conditions. However, in the natural environment, diurnal outputs result from complex interactions of endogenous circadian rhythms and external cues. Accumulated studies using the hypocotyl as a model for plant growth have shown that both light signalling and circadian clock mutants have growth defects, suggesting strong interactions between hypocotyl elongation, light signalling and the circadian clock. Here, we review evidence suggesting that light, plant hormones and the circadian clock all interact to control diurnal patterns of plant growth.
Topics: Biological Clocks; Circadian Rhythm; Gene Expression Regulation, Plant; Hypocotyl; Light; Plant Growth Regulators; Plant Proteins; Sunlight; Time Factors
PubMed: 17080594
DOI: 10.1111/j.1365-3040.2005.01489.x -
Cells Nov 2023The function of the circadian cycle is to determine the natural 24 h biological rhythm, which includes physiological, metabolic, and hormonal changes that occur daily in... (Review)
Review
The function of the circadian cycle is to determine the natural 24 h biological rhythm, which includes physiological, metabolic, and hormonal changes that occur daily in the body. This cycle is controlled by an internal biological clock that is present in the body's tissues and helps regulate various processes such as sleeping, eating, and others. Interestingly, animal models have provided enough evidence to assume that the alteration in the circadian system leads to the appearance of numerous diseases. Alterations in breathing patterns in lung diseases can modify oxygenation and the circadian cycles; however, the response mechanisms to hypoxia and their relationship with the clock genes are not fully understood. Hypoxia is a condition in which the lack of adequate oxygenation promotes adaptation mechanisms and is related to several genes that regulate the circadian cycles, the latter because hypoxia alters the production of melatonin and brain physiology. Additionally, the lack of oxygen alters the expression of clock genes, leading to an alteration in the regularity and precision of the circadian cycle. In this sense, hypoxia is a hallmark of a wide variety of lung diseases. In the present work, we intended to review the functional repercussions of hypoxia in the presence of asthma, chronic obstructive sleep apnea, lung cancer, idiopathic pulmonary fibrosis, obstructive sleep apnea, influenza, and COVID-19 and its repercussions on the circadian cycles.
Topics: Animals; Humans; Circadian Rhythm; Hypoxia; Biological Clocks; Sleep Apnea, Obstructive; Lung Diseases
PubMed: 38067152
DOI: 10.3390/cells12232724 -
Diabetes, Obesity & Metabolism Sep 2015The circadian clock orchestrates the co-ordinated rhythmicity of numerous metabolic pathways to anticipate daily and seasonal changes in energy demand. This vital... (Review)
Review
The circadian clock orchestrates the co-ordinated rhythmicity of numerous metabolic pathways to anticipate daily and seasonal changes in energy demand. This vital physiological function is controlled by a set of individual clock components that are present in each cell of the body, and regulate each other as well as clock output genes. A key factor is the nuclear receptor, Rev-erbα, a transcriptional repressor which functions not only as a clock component but also as a modulator of metabolic programming in an array of tissues. This review explores the role of Rev-erbα in mediating this crosstalk between circadian rhythm and tissue-specific biological networks and its relevance to organismal physiology.
Topics: Biological Clocks; CLOCK Proteins; Circadian Rhythm; Humans; Nuclear Receptor Subfamily 1, Group D, Member 1; Transcription, Genetic
PubMed: 26332963
DOI: 10.1111/dom.12510 -
Medecine Sciences : M/S 2022The biological clock is a set of evolutionarily conserved "clock proteins" that generate circadian rhythms in behavior and physiological processes. The clock programs... (Review)
Review
The biological clock is a set of evolutionarily conserved "clock proteins" that generate circadian rhythms in behavior and physiological processes. The clock programs these processes at specific times of the day, allowing the organism to optimize its functions by anticipating predictable daily changes such as day/night, hence sleep/wake or feeding/fasting cycles. Modern lifestyle, i.e., exposure to light at night, shift work and irregular eating patterns and sleep schedules desynchronize the clocks residing in each organ. This dissonance is associated with an increased risk of developing various diseases such as cancer, metabolic, cardiovascular and chronic inflammatory diseases.
Topics: Circadian Clocks; Circadian Rhythm; Humans; Receptors, Cytoplasmic and Nuclear; Sleep
PubMed: 36094237
DOI: 10.1051/medsci/2022102 -
Cell Systems Apr 2021The fundamental mechanisms that control and regulate biological organisms exhibit a surprising level of complexity. Oscillators are perhaps the simplest motifs that... (Review)
Review
The fundamental mechanisms that control and regulate biological organisms exhibit a surprising level of complexity. Oscillators are perhaps the simplest motifs that produce time-varying dynamics and are ubiquitous in biological systems. It is also known that such biological oscillators interact with each other-for instance, circadian oscillators affect the cell cycle, and somitogenesis clock proteins in adjacent cells affect each other in developing embryos. Therefore, it is vital to understand the effects that can emerge from non-linear interaction between oscillations. Here, we show how oscillations typically arise in biology and take the reader on a tour through the great variety in dynamics that can emerge even from a single pair of coupled oscillators. We explain how chaotic dynamics can emerge and outline the methods of detecting this in experimental time traces. Finally, we discuss the potential role of such complex dynamical features in biological systems.
Topics: Biological Clocks; Biology; Humans
PubMed: 33887201
DOI: 10.1016/j.cels.2021.03.003 -
Frontiers in Neuroendocrinology Jan 2014In birds, biological clock function pervades all aspects of biology, controlling daily changes in sleep: wake, visual function, song, migratory patterns and orientation,... (Review)
Review
In birds, biological clock function pervades all aspects of biology, controlling daily changes in sleep: wake, visual function, song, migratory patterns and orientation, as well as seasonal patterns of reproduction, song and migration. The molecular bases for circadian clocks are highly conserved, and it is likely the avian molecular mechanisms are similar to those expressed in mammals, including humans. The central pacemakers in the avian pineal gland, retinae and SCN dynamically interact to maintain stable phase relationships and then influence downstream rhythms through entrainment of peripheral oscillators in the brain controlling behavior and peripheral tissues. Birds represent an excellent model for the role played by biological clocks in human neurobiology; unlike most rodent models, they are diurnal, they exhibit cognitively complex social interactions, and their circadian clocks are more sensitive to the hormone melatonin than are those of nocturnal rodents.
Topics: Animals; Behavior, Animal; Biological Clocks; Birds; Brain; Humans; Melatonin
PubMed: 24157655
DOI: 10.1016/j.yfrne.2013.10.002 -
International Journal of Molecular... Jun 2019Nowadays, high epidemic obesity-triggered hypertension and diabetes seriously damage social public health. There is now a general consensus that the body's fat content... (Review)
Review
Nowadays, high epidemic obesity-triggered hypertension and diabetes seriously damage social public health. There is now a general consensus that the body's fat content exceeding a certain threshold can lead to obesity. Calcium ion is one of the most abundant ions in the human body. A large number of studies have shown that calcium signaling could play a major role in increasing energy consumption by enhancing the metabolism and the differentiation of adipocytes and reducing food intake through regulating neuronal excitability, thereby effectively decreasing the occurrence of obesity. In this paper, we review multiple calcium signaling pathways, including the IP3 (inositol 1,4,5-trisphosphate)-Ca (calcium ion) pathway, the p38-MAPK (mitogen-activated protein kinase) pathway, and the calmodulin binding pathway, which are involved in biological clock, intestinal microbial activity, and nerve excitability to regulate food intake, metabolism, and differentiation of adipocytes in mammals, resulting in the improvement of obesity.
Topics: Animals; Biological Clocks; Calcium Signaling; Gastrointestinal Microbiome; Humans; Models, Biological; Nervous System; Obesity
PubMed: 31195699
DOI: 10.3390/ijms20112768 -
Journal of Anatomy Aug 2020Dentine- and enamel-forming cells secrete matrix in consistent rhythmic phases, resulting in the formation of successive microscopic growth lines inside tooth crowns and...
Dentine- and enamel-forming cells secrete matrix in consistent rhythmic phases, resulting in the formation of successive microscopic growth lines inside tooth crowns and roots. Experimental studies of various mammals have proven that these lines are laid down in subdaily, daily (circadian), and multidaily rhythms, but it is less clear how these rhythms are initiated and maintained. In 2001, researchers reported that lesioning the so-called master biological clock, the suprachiasmatic nucleus (SCN), halted daily line formation in rat dentine, whereas subdaily lines persisted. More recently, a key clock gene (Bmal1) expressed in the SCN in a circadian manner was also found to be active in dentine- and enamel- secretory cells. To probe these potential neurological and local mechanisms for the production of rhythmic lines in teeth, we reexamined the role of the SCN in growth line formation in Wistar rats and investigated the presence of daily lines in Bmal1 knockout mice (Bmal1 ). In contrast to the results of the 2001 study, we found that both daily and subdaily growth lines persisted in rat dentine after complete or partial SCN lesion in the majority of individuals. In mice, after transfer into constant darkness, daily rhythms continued to manifest as incremental lines in the dentine of each Bmal1 genotype (wild-type, Bmal , and Bmal1 ). These results affirm that the manifestation of biological rhythms in teeth is a robust phenomenon, imply a more autonomous role of local biological clocks in tooth growth than previously suggested, and underscore the need further to elucidate tissue-specific circadian biology and its role in incremental line formation. Investigations of this nature will strengthen an invaluable system for determining growth rates and calendar ages from mammalian hard tissues, as well as documenting the early lives of fossil hominins and other primates.
Topics: ARNTL Transcription Factors; Animals; Biological Clocks; Circadian Rhythm; Dentin; Mice; Mice, Knockout; Rats; Rats, Wistar
PubMed: 32266720
DOI: 10.1111/joa.13198