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Biological clock

Danielle Gulick, Joshua J Gamsby
Although potent effects of psychoactive drugs on circadian rhythms were first described over 30 years ago, research into the reciprocal relationship between the reward system and the circadian system - and the impact of this relationship on addiction - has only become a focus in the last decade. Nonetheless, great progress has been made in that short time toward understanding how drugs of abuse impact the molecular and physiological circadian clocks, as well as how disruption of normal circadian rhythm biology may contribute to addiction and ameliorate the efficacy of treatments for addiction...
March 15, 2018: Pharmacology & Therapeutics
Michael Cleary-Gaffney, Andrew N Coogan
Circadian rhythms are recurring patterns in a range of behavioural, physiological and molecular parameters that display periods of near 24 h, and are underpinned by an endogenous biological timekeeping system. Circadian clocks are increasingly recognised as being key for health. Environmental light is the key stimulus that synchronises the internal circadian system with the external time cues. There are emergent health concerns regarding increasing worldwide prevalence of electric lighting, especially man-made light-at-night, and light's impact on the circadian system may be central to these effects...
March 11, 2018: Physiology & Behavior
Fan Lou, Ming Li, Xiaoguang Luo, Yan Ren
Background: The clock genes controlling biological rhythm play an important role in the pathophysiology of aging. The purpose of this study was to determine whether there is an association between a variant of the circadian locomotor output cycles kaput (CLOCK) gene and circadian dysfunction of Parkinson's disease (PD). Methods: Six hundred and forty-six cases of Parkinson's disease from consecutive outpatients and inpatients ward from our hospital were included in this study...
2018: Parkinson's Disease
Ha Kyun Kim, Hyun Jung Kim, Jae Hyung Kim, Tae Hoon Kim, Sang Hag Lee
Numerous peripheral tissues possess self-sustaining daily biologic rhythms that are regulated at the molecular level by clock genes such as PER1, PER2, CLOCK, and BMAL1. Physiological function of nasal mucosa exhibits rhythmic variability to a day-night environmental cycle. Nevertheless, little is known of the expression and distribution pattern of clock genes in nasal mucosa. The present study investigates the expression level and distribution pattern of PER1, PER2, CLOCK, and BMAL1 genes in nasal mucosa of healthy controls, allergic rhinitis patients, and normal rats...
2018: PloS One
Claudia Bozzaro
In western societies, a growing number of women are currently turning to social egg freezing, a technique that makes it possible to freeze oocytes and thus preserve female reproductive possibilities. The current ethical debate has focused on normative aspects concerning the question of whether social egg freezing empowers women's reproductive autonomy. Due to this narrow focus on autonomy, deeper questions concerning the socio-economic conditions and cultural factors that lead women to delay reproduction, to feel pressured by their biological clock, and thus to consider social egg freezing have not yet received sufficient attention and analysis...
February 23, 2018: Reproductive Biomedicine Online
Ruijun He, Min Cui, Hui Lin, Lei Zhao, Jiayu Wang, Songfeng Chen, Zengwu Shao
AIMS: Intervertebral disc degeneration (IVDD) is thought to be the major cause of low back pain (LBP), which is still in lack of effective etiological treatment. Oxidative stress has been demonstrated to participate in the impairment of nucleus pulposus cells (NPCs). As the most important neuroendocrine hormone in biological clock regulation, melatonin (MLT) is also featured by good antioxidant effect. In this study, we investigated the effect and mechanisms of melatonin on oxidative stress-induced damage in rat NPCs...
March 8, 2018: Life Sciences
Marco Caterino, Tiziana Squillaro, Daniela Montesarchio, Antonio Giordano, Concetta Giancola, Mariarosa A B Melone
Huntington's disease is a dreadful, incurable disorder. It springs from the autosomal dominant mutation in the first exon of the HTT gene, which encodes for the huntingtin protein (HTT) and results in progressive neurodegeneration. Thus far, all the attempted approaches to tackle the mutant HTT-induced toxicity causing this disease have failed. The mutant protein comes with the aberrantly expanded poly-glutamine tract. It is primarily to blame for the build-up of β-amyloid-like HTT aggregates, deleterious once broadened beyond the critical ∼35-37 repeats threshold...
March 8, 2018: Neuropharmacology
Ariel Amir, Nathalie Q Balaban
For many decades, the wedding of quantitative data with mathematical modeling has been fruitful, leading to important biological insights. Here, we review some of the ongoing efforts to gain insights into problems in microbiology - and, in particular, cell-cycle progression and its regulation - through observation and quantitative analysis of the natural fluctuations in the system. We first illustrate this idea by reviewing a classic example in microbiology - the Luria-Delbrück experiment - and discussing how, in that case, useful information was obtained by looking beyond the mean outcome of the experiment, but instead paying attention to the variability between replicates of the experiment...
March 8, 2018: Trends in Microbiology
Allan B James, Stuart Sullivan, Hugh G Nimmo
How plants perceive and respond to temperature remains an important question in the plant sciences. Temperature perception and signal transduction may occur through temperature-sensitive intra-molecular folding of primary mRNA transcripts. Recent studies suggested a role for retention of the first intron in the 5'UTR of the clock component LATE ELONGATED HYPOCOTYL (LHY) in response to changes in temperature. Here we identified a set of haplotypes in the LHY 5'UTR, examined their global spatial distribution and obtained evidence that haplotype can affect temperature-dependent splicing of LHY transcripts...
March 8, 2018: Plant, Cell & Environment
Yan Zhang, Kai-Uwe Saum, Ben Schöttker, Bernd Holleczek, Hermann Brenner
Survival predictors are of potential use for informing on biological age and targeting prevention of aging-related morbidity. We assessed associations of 2 novel methylomic survival indicators, a methylation-based mortality risk score (MRscore) and the epigenetic clock-derived age acceleration (AA), with a well-known survival predictor, frailty index (FI), and compared the 3 indicators in mortality prediction. In a large population-based cohort with 14-year follow-up, we found both MRscore and AA to be independently associated with FI, but the association was much stronger for MRscore than for AA...
March 6, 2018: Aging
Abeer Fadda, Mohammed El Anbari, Andrey Ptitsyn
BACKGROUND: Oscillations of different origin, period and amplitude play an important role in the regulation of cellular processes. Most widely studied is the circadian or approximately daily variation in gene expression activity. Timing of gene expression is controlled by internal molecular clock keeping steady periodic expression. In this study, we shift attention towards a broad range of periodically expressed genes involved in multiple cellular functions which may or may not be under direct control of the intrinsic circadian clock...
February 13, 2018: BMC Medical Genomics
Simon E Freeman, Lloyd Emokpae, Jeffrey S Rogers, Geoffrey F Edelmann
Recently developed low-power Chip-Scale Atomic Clocks (CSACs) hold promise for underwater acoustics applications because they enable time-coherent processing, critical for estimating the directionality of the sound field, when acoustic array elements cannot share a timing reference. Controlled, tank-based experiments with a small acoustic array (N = 4) featuring CSAC-equipped elements show that optimal disciplining is important for continued array coherence. Clock drift equivalent to a 10% wavelength error at 0...
February 2018: Journal of the Acoustical Society of America
Chiara Tesoriero, Yuan-Zhong Xu, Dieudonné Mumba Ngoyi, Marina Bentivoglio
Trypanosoma brucei ( T. b. ) gambiense is the parasite subspecies responsible for most reported cases of human African trypanosomiasis (HAT) or sleeping sickness. This severe infection leads to characteristic disruption of the sleep-wake cycle, recalling attention on the circadian timing system. Most animal models of the disease have been hitherto based on infection of laboratory rodents with the T. b. brucei subspecies, which is not infectious to humans. In these animal models, functional, rather than structural, alterations of the master circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN), have been reported...
2018: Frontiers in Neuroanatomy
Donají Chi-Castañeda, Arturo Ortega
Circadian rhythms are biological oscillations with a period of ~24 h. These rhythms are orchestrated by a circadian timekeeper in the suprachiasmatic nucleus of the hypothalamus, the circadian " master clock ," which exactly adjusts clock outputs to solar time via photic synchronization. At the molecular level, circadian rhythms are generated by the interaction of positive and negative feedback loops of transcriptional and translational processes of the so-called " clock genes ." A large number of clock genes encode numerous proteins that regulate their own transcription and that of other genes, collectively known as " clock-controlled genes ...
2018: Frontiers in Physiology
S Y Christin Chong, Lijuan Xin, Louis J Ptáček, Ying-Hui Fu
Sleep is fundamental to the survival of humans. However, knowledge regarding the role of sleep and its regulation is poorly understood. Genetics in flies, mice, and humans has led to a detailed understanding of some aspects of circadian regulation. Sleep homeostasis (the effect of increasing periods of wakefulness on our sleep propensity) is largely not understood. Sleep homeostasis is distinct from, but also linked to, the circadian clock. It is only in the last two decades that our understanding of some sleep disorders has been revealed...
2018: Handbook of Clinical Neurology
Katharina F Sonnen, Volker M Lauschke, Julia Uraji, Henning J Falk, Yvonne Petersen, Maja C Funk, Mathias Beaupeux, Paul François, Christoph A Merten, Alexander Aulehla
How signaling dynamics encode information is a central question in biology. During vertebrate development, dynamic Notch signaling oscillations control segmentation of the presomitic mesoderm (PSM). In mouse embryos, this molecular clock comprises signaling oscillations of several pathways, i.e., Notch, Wnt, and FGF signaling. Here, we directly address the role of the relative timing between Wnt and Notch signaling oscillations during PSM patterning. To this end, we developed a new experimental strategy using microfluidics-based entrainment that enables specific control of the rhythm of segmentation clock oscillations...
February 22, 2018: Cell
Jonathan Gaucher, Emilie Montellier, Paolo Sassone-Corsi
The cell cycle and the circadian clock operate as biological oscillators whose timed functions are tightly regulated. Accumulating evidence illustrates the presence of molecular links between these two oscillators. This mutual interplay utilizes various coupling mechanisms, such as the use of common regulators. The connection between these two cyclic systems has unique interest in the context of aberrant cell proliferation since both of these oscillators are frequently misregulated in cancer cells. Further studies will provide deeper understanding of the detailed molecular connections between the cell cycle and the circadian clock and may also serve as a basis for the design of innovative therapeutic strategies...
February 19, 2018: Trends in Cell Biology
Sébrina Aubin, Julie A E Christensen, Poul Jennum, Tore Nielsen, Ron Kupers, Maurice Ptito
The loss of vision, particularly when it occurs early in life, is associated with compensatory cortical plasticity not only in the visual cortical areas, but throughout the entire brain. The absence of visual input to the retina can also induce changes in entrainment of the circadian rhythm, as light is the primary zeitgeber of the master biological clock found in the suprachiasmatic nucleus of the hypothalamus. In addition, a greater number of sleep disturbances is often reported in blind individuals. Here, we examined various electroencephalographic microstructural components of sleep, both during rapid-eye-movement (REM) sleep and non-REM (NREM) sleep, between blind individuals, including both of early and late onset, and normal-sighted controls...
February 2018: Sleep Medicine
Simone Mocellin, Saveria Tropea, Clara Benna, Carlo Riccardo Rossi
BACKGROUND: Dysfunction of the circadian clock and single polymorphisms of some circadian genes have been linked to cancer susceptibility, although data are scarce and findings inconsistent. We aimed to investigate the association between circadian pathway genetic variation and risk of developing common cancers based on the findings of genome-wide association studies (GWASs). METHODS: Single nucleotide polymorphisms (SNPs) of 17 circadian genes reported by three GWAS meta-analyses dedicated to breast (Discovery, Biology, and Risk of Inherited Variants in Breast Cancer (DRIVE) Consortium; cases, n = 15,748; controls, n = 18,084), prostate (Elucidating Loci Involved in Prostate Cancer Susceptibility (ELLIPSE) Consortium; cases, n = 14,160; controls, n = 12,724) and lung carcinoma (Transdisciplinary Research In Cancer of the Lung (TRICL) Consortium; cases, n = 12,160; controls, n = 16,838) in patients of European ancestry were utilized to perform pathway analysis by means of the adaptive rank truncated product (ARTP) method...
February 19, 2018: BMC Medicine
Daniela Ballotta, Fausta Lui, Carlo Adolfo Porro, Paolo Frigio Nichelli, Francesca Benuzzi
According to the Scalar Expectancy Theory, humans are equipped with a biological internal clock, possibly modulated by attention and arousal. Both emotions and pain are arousing and can absorb attentional resources, thus causing distortions of temporal perception. The aims of the present single-event fMRI study were to investigate: a) whether observation of facial expressions of pain interferes with time production; and b) the neural network subserving this kind of temporal distortions. Thirty healthy volunteers took part in the study...
2018: PloS One
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