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Circadian biology

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https://www.readbyqxmd.com/read/28803778/an-unstable-singularity-underlies-stochastic-phasing-of-the-circadian-clock-in-individual-cyanobacterial-cells
#1
Siting Gan, Erin K O'Shea
The endogenous circadian clock synchronizes with environmental time by appropriately resetting its phase in response to external cues. Of note, some resetting stimuli induce attenuated oscillations of clock output, which has been observed at the population-level in several organisms and in studies of individual humans. To investigate what is happening in individual cellular clocks, we studied the unicellular cyanobacterium S. elongatus. By measuring its phase-resetting responses to temperature changes, we found that population-level arrhythmicity occurs when certain perturbations cause stochastic phases of oscillations in individual cells...
August 9, 2017: Molecular Cell
https://www.readbyqxmd.com/read/28802034/keeping-the-rhythm-while-changing-the-lyrics-circadian-biology-in-aging
#2
Fumiyuki Hatanaka, Alejandro Ocampo, Juan Carlos Izpisua Belmonte
Aging and circadian rhythms have been linked for decades, but their molecular interplay has remained obscure. Sato et al. and Solanas et al. now reveal that, while core clock components remain nearly unaltered, aging is associated with tissue-specific rewiring, which can be prevented by calorie restriction.
August 10, 2017: Cell
https://www.readbyqxmd.com/read/28799406/a-polymorphic-ggc-repeat-in-the-npas2-gene-and-its-association-with-melanoma
#3
Alessandra Franzoni, Elitza Markova-Car, Sanja Dević-Pavlić, Davor Jurišić, Cinzia Puppin, Catia Mio, Marila De Luca, Giulia Petruz, Giuseppe Damante, Sandra Kraljević Pavelić
Circadian clock regulation in mammals is controlled by feedback loops of a set of circadian genes. One of these circadian genes, NPAS2, encodes for a member of the bHLH-PAS class of transcription factors and is expressed in the forebrain and in some peripheral organs such as liver and skin. Other biological processes are also regulated by circadian genes. For example, NPAS2 is involved in cell proliferation, DNA damage repair and malignant transformation. Aberrant expression of clock genes has been previously observed in melanoma which led to our effort to sequence the NPAS2 promoter region in this cancer type...
January 1, 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28797239/nutrient-supply-affects-the-mrna-expression-profile-of-the-porcine-skeletal-muscle
#4
Tainã Figueiredo Cardoso, Raquel Quintanilla, Joan Tibau, Marta Gil, Emilio Mármol-Sánchez, Olga González-Rodríguez, Rayner González-Prendes, Marcel Amills
BACKGROUND: The genetic basis of muscle fat deposition in pigs is not well known. So far, we have only identified a limited number of genes involved in the absorption, transport, storage and catabolism of lipids. Such information is crucial to interpret, from a biological perspective, the results of genome-wide association analyses for intramuscular fat content and composition traits. Herewith, we have investigated how the ingestion of food changes gene expression in the gluteus medius muscle of Duroc pigs...
August 10, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28792639/circadian-rhythms-vary-over-the-growing-season-and-correlate-with-fitness-components
#5
Matthew J Rubin, Marcus T Brock, Amanda M Davis, Zachary M German, Mary Knapp, Stephen M Welch, Stacey L Harmer, Julin N Maloof, Seth J Davis, Cynthia Weinig
Circadian clocks have evolved independently in all three domains of life, suggesting that internal mechanisms of time-keeping are adaptive in contemporary populations. However, the performance consequences of either discrete or quantitative clock variation have rarely been tested in field settings. Clock sensitivity of diverse segregating lines to the environment remains uncharacterized as do the statistical genetic parameters that determine evolutionary potential. In field studies with Arabidopsis thaliana, we found that major perturbations to circadian cycle length (referred to as clock period) via mutation reduce both survival and fecundity...
August 9, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28780758/investigation-of-metabolites-for-estimating-blood-deposition-time
#6
Karolina Lech, Fan Liu, Sarah K Davies, Katrin Ackermann, Joo Ern Ang, Benita Middleton, Victoria L Revell, Florence J Raynaud, Igor Hoveijn, Roelof A Hut, Debra J Skene, Manfred Kayser
Trace deposition timing reflects a novel concept in forensic molecular biology involving the use of rhythmic biomarkers for estimating the time within a 24-h day/night cycle a human biological sample was left at the crime scene, which in principle allows verifying a sample donor's alibi. Previously, we introduced two circadian hormones for trace deposition timing and recently demonstrated that messenger RNA (mRNA) biomarkers significantly improve time prediction accuracy. Here, we investigate the suitability of metabolites measured using a targeted metabolomics approach, for trace deposition timing...
August 5, 2017: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/28777176/circadian-rhythm-sleep-wake-disorders
#7
Milena Pavlova
PURPOSE OF REVIEW: The endogenous circadian rhythms are one of the cardinal processes that control sleep. They are self-sustaining biological rhythms with a periodicity of approximately 24 hours that may be entrained by external zeitgebers (German for time givers), such as light, exercise, and meal times. This article discusses the physiology of the circadian rhythms, their relationship to neurologic disease, and the presentation and treatment of circadian rhythm sleep-wake disorders...
August 2017: Continuum: Lifelong Learning in Neurology
https://www.readbyqxmd.com/read/28775132/shift-work-that-involves-circadian-disruption-and-breast-cancer-a-first-application-of-chronobiological-theory-and-the-consequent-challenges
#8
Lin Fritschi, J Valérie Groß, Ursula Wild, Jane S Heyworth, Deborah C Glass, Thomas C Erren
OBJECTIVES: In 2007, the International Agency for Research on Cancer classified shift work involving circadian disruption (CD) as probably carcinogenic to humans. Circadian disruption could be conceptualised as the overlap of activity, such as work, with an individual's biological night. The latter can be approximated from a worker's chronotype (or morning/evening preference). Few previous studies have taken chronotype into account when assessing CD caused by shift work. Our objective was to test the hypothesis that women working during their biological night would be at increased risk of breast cancer...
August 3, 2017: Occupational and Environmental Medicine
https://www.readbyqxmd.com/read/28758689/the-antiphasic-regulatory-module-comprising-cdf5-and-its-antisense-rna-flore-links-the-circadian-clock-to-photoperiodic-flowering
#9
Rossana Henriques, Huan Wang, Jun Liu, Marc Boix, Li-Fang Huang, Nam-Hai Chua
Circadian rhythms of gene expression are generated by the combinatorial action of transcriptional and translational feedback loops as well as chromatin remodelling events. Recently, long noncoding RNAs (lncRNAs) that are natural antisense transcripts (NATs) to transcripts encoding central oscillator components were proposed as modulators of core clock function in mammals (Per) and fungi (frq/qrf). Although oscillating lncRNAs exist in plants, their functional characterization is at an initial stage. By screening an Arabidopsis thaliana lncRNA custom-made array we identified CDF5 LONG NONCODING RNA (FLORE), a circadian-regulated lncRNA that is a NAT of CDF5...
July 31, 2017: New Phytologist
https://www.readbyqxmd.com/read/28757615/ror%C3%AE-controls-hepatic-lipid-homeostasis-via-negative-regulation-of-ppar%C3%AE-transcriptional-network
#10
Kyeongkyu Kim, Kyungjin Boo, Young Suk Yu, Se Kyu Oh, Hyunkyung Kim, Yoon Jeon, Jinhyuk Bhin, Daehee Hwang, Keun Il Kim, Jun-Su Lee, Seung-Soon Im, Seul Gi Yoon, Il Yong Kim, Je Kyung Seong, Ho Lee, Sungsoon Fang, Sung Hee Baek
The retinoic acid receptor-related orphan receptor-α (RORα) is an important regulator of various biological processes, including cerebellum development, circadian rhythm and cancer. Here, we show that hepatic RORα controls lipid homeostasis by negatively regulating transcriptional activity of peroxisome proliferators-activated receptor-γ (PPARγ) that mediates hepatic lipid metabolism. Liver-specific Rorα-deficient mice develop hepatic steatosis, obesity and insulin resistance when challenged with a high-fat diet (HFD)...
July 31, 2017: Nature Communications
https://www.readbyqxmd.com/read/28756747/nampt-mediated-nad-biosynthesis-as-the-internal-timing-mechanism-in-nad-world-time-is-running-in-its-own-way
#11
Borut Poljsak
The biological age of organisms differs from the chronological age and is determined by internal aging clock(s). How cells estimate time on a scale of 24 h is relatively well-studied; however, how biological time is measured by cells, tissues, organs or organisms in longer time periods (years and decades) is largely unknown. What is clear and widely agreed upon is that the link to age and age-related diseases is not chronological, as it does not depend on a fixed passage of time. Rather, this link depends on the biological age of an individual cell, tissue, organ or organism and not on time in a strictly chronological sense...
July 29, 2017: Rejuvenation Research
https://www.readbyqxmd.com/read/28752422/regulation-of-clock-genes-by-adrenergic-receptor-signaling-in-osteoblasts
#12
Takao Hirai
The clock system has been identified as one of the major mechanisms controlling cellular functions. Circadian clock gene oscillations also actively participate in the functions of various cell types including bone-related cells. Previous studies demonstrated that clock genes were expressed in bone tissue and also that their expression exhibited circadian rhythmicity. Recent findings have shown that sympathetic tone plays a central role in biological oscillations in bone. Adrenergic receptor (AR) signaling regulates the expression of clock genes in cancellous bone...
July 27, 2017: Neurochemical Research
https://www.readbyqxmd.com/read/28744188/circadian-metabolomics-in-time-and-space
#13
REVIEW
Kenneth A Dyar, Kristin L Eckel-Mahan
Circadian rhythms are widely known to govern human health and disease, but specific pathogenic mechanisms linking circadian disruption to metabolic diseases are just beginning to come to light. This is thanks in part to the development and application of various "omics"-based tools in biology and medicine. Current high-throughput technologies allow for the simultaneous monitoring of multiple dynamic cellular events over time, ranging from gene expression to metabolite abundance and sub-cellular localization...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28742083/long-time-analytic-approximation-of-large-stochastic-oscillators-simulation-analysis-and-inference
#14
Giorgos Minas, David A Rand
In order to analyse large complex stochastic dynamical models such as those studied in systems biology there is currently a great need for both analytical tools and also algorithms for accurate and fast simulation and estimation. We present a new stochastic approximation of biological oscillators that addresses these needs. Our method, called phase-corrected LNA (pcLNA) overcomes the main limitations of the standard Linear Noise Approximation (LNA) to remain uniformly accurate for long times, still maintaining the speed and analytically tractability of the LNA...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28732508/lysophosphatidic-acid-plasma-concentrations-in-healthy-subjects-circadian-rhythm-and-associations-with-demographic-anthropometric-and-biochemical-parameters
#15
Anna Michalczyk, Marta Budkowska, Barbara Dołęgowska, Dariusz Chlubek, Krzysztof Safranow
BACKGROUND: Lysophosphatidic acid (LPA) is a bioactive lipid with a wide biological activity. Previous studies have shown its potential usefulness as a diagnostic marker for ovarian cancer. The aim of the study was to investigate which factors may influence plasma LPA concentrations in healthy subjects and to propose reference values. METHODS: The study group consisted of 100 healthy subjects. From all of them the blood samples were taken at 7 a.m. (fasting state)...
July 21, 2017: Lipids in Health and Disease
https://www.readbyqxmd.com/read/28731659/neonatal-intensive-care-unit-lighting-update-and-recommendations
#16
Roberto G Rodríguez, Andrea E Pattini
Achieving adequate lighting in neonatal intensive care units is a major challenge: in addition to the usual considerations of visual performance, cost, energy and aesthetics, there appear different biological needs of patients, health care providers and family members. Communicational aspects of light, its role as a facilitator of the visual function of doctors and nurses, and its effects on the newborn infant physiology and development were addressed in order to review the effects of light (natural and artificial) within neonatal care with a focus on development...
August 1, 2017: Archivos Argentinos de Pediatría
https://www.readbyqxmd.com/read/28730970/healthy-diet-and-reduction-of-chronic-disease-risks-of-night-shift-workers
#17
Giovanni M Ferri, Domenica Cavone, Graziana Intranuovo, Linda Macinagrossa
BACKGROUND: The large increase in epidemiological studies on night shift work is due to the important effects of night shift work on workers' health and psychophysical wellbeing. The short-term effects-insomnia, difficulties in managing work and private life, lower work performance, and more work and extra-work accidents-are easily studied. However, there are several long-term effects that are difficult to study because of the need for detailed exposure assessment and the long latency periods of these diseases...
July 20, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28724246/health-consequences-of-electric-lighting-practices-in-the-modern-world-a-report-on-the-national-toxicology-program-s-workshop-on-shift-work-at-night-artificial-light-at-night-and-circadian-disruption
#18
REVIEW
Ruth M Lunn, David E Blask, Andrew N Coogan, Mariana G Figueiro, Michael R Gorman, Janet E Hall, Johnni Hansen, Randy J Nelson, Satchidananda Panda, Michael H Smolensky, Richard G Stevens, Fred W Turek, Roel Vermeulen, Tania Carreón, Claire C Caruso, Christina C Lawson, Kristina A Thayer, Michael J Twery, Andrew D Ewens, Sanford C Garner, Pamela J Schwingl, Windy A Boyd
The invention of electric light has facilitated a society in which people work, sleep, eat, and play at all hours of the 24-hour day. Although electric light clearly has benefited humankind, exposures to electric light, especially light at night (LAN), may disrupt sleep and biological processes controlled by endogenous circadian clocks, potentially resulting in adverse health outcomes. Many of the studies evaluating adverse health effects have been conducted among night- and rotating-shift workers, because this scenario gives rise to significant exposure to LAN...
July 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28719655/protein-analysis-and-gene-expression-indicate-differential-vulnerability-of-iberian-fish-species-under-a-climate-change-scenario
#19
Tiago F Jesus, João M Moreno, Tiago Repolho, Alekos Athanasiadis, Rui Rosa, Vera M F Almeida-Val, Maria M Coelho
Current knowledge on the biological responses of freshwater fish under projected scenarios of climate change remains limited. Here, we examine differences in the protein configuration of two endemic Iberian freshwater fish species, Squalius carolitertii and the critically endangered S. torgalensis that inhabit in the Atlantic-type northern and in the Mediterranean-type southwestern regions, respectively. We performed protein structure modeling of fourteen genes linked to protein folding, energy metabolism, circadian rhythms and immune responses...
2017: PloS One
https://www.readbyqxmd.com/read/28715993/metabolic-effects-of-intermittent-fasting
#20
Ruth E Patterson, Dorothy D Sears
The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved health outcomes. A MEDLINE search was performed using PubMed and the terms "intermittent fasting," "fasting," "time-restricted feeding," and "food timing." Modified fasting regimens appear to promote weight loss and may improve metabolic health. Several lines of evidence also support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals may result in sustained improvements in human health...
July 17, 2017: Annual Review of Nutrition
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