1,472 results match your criteria Journal of biological rhythms[Journal]


Pregnancy Induces an Earlier Chronotype in Both Mice and Women.

J Biol Rhythms 2019 Apr 24:748730419844650. Epub 2019 Apr 24.

Department of Biology, Washington University, St. Louis, MO, USA.

Daily rhythms generated by endogenous circadian mechanisms and synchronized to the light-dark cycle have been implicated in the timing of birth in a wide variety of species. Although chronodisruption (e.g. Read More

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http://dx.doi.org/10.1177/0748730419844650DOI Listing

Neuronal Activity in Non-LNv Clock Cells Is Required to Produce Free-Running Rest:Activity Rhythms in Drosophila.

J Biol Rhythms 2019 Apr 17:748730419841468. Epub 2019 Apr 17.

Department of Biology, Loyola University, Chicago, IL, USA.

Circadian rhythms in behavior and physiology are produced by central brain clock neurons that can be divided into subpopulations based on molecular and functional characteristics. It has become clear that coherent behavioral rhythms result from the coordinated action of these clock neuron populations, but many questions remain regarding the organizational logic of the clock network. Here we used targeted genetic tools in Drosophila to eliminate either molecular clock function or neuronal activity in discrete clock neuron subsets. Read More

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http://dx.doi.org/10.1177/0748730419841468DOI Listing

Distinct Physiological Mechanisms Induce Latitudinal and Sexual Differences in the Photoperiodic Induction of Diapause in a Fly.

J Biol Rhythms 2019 Apr 9:748730419841931. Epub 2019 Apr 9.

Graduate School of Science, Osaka City University, Japan.

Many temperate insects enter diapause (dormancy) for overwintering in response to short days (long nights). A latitudinal cline in the critical day lengths for the photoperiodic induction of diapause has been reported in various insect species. However, the physiological mechanisms underlying this cline have remained elusive. Read More

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http://dx.doi.org/10.1177/0748730419841931DOI Listing

Involvement of the Clock Gene period in the Circadian Rhythm of the Silkmoth Bombyx mori.

J Biol Rhythms 2019 Apr 5:748730419841185. Epub 2019 Apr 5.

Graduate School of Science, Kyoto University, Kyoto, Japan.

In Lepidoptera, the roles of period ( per) and the negative feedback involving this gene in circadian rhythm are controversial. In the present study, we established a per knockout strain using TALEN in Bombyx mori, and compared eclosion and hatching rhythms between the per-knockout and wild-type strains to examine whether per is actually involved in these rhythms. The generated per knockout allele was considered null, because it encoded an extensively truncated form of PERIOD (198 aa due to a 64-bp deletion in exon 7, in contrast to 1113 aa in the wild-type protein). Read More

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http://journals.sagepub.com/doi/10.1177/0748730419841185
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http://dx.doi.org/10.1177/0748730419841185DOI Listing
April 2019
4 Reads

Circadian Clock Properties and Their Relationships as a Function of Free-Running Period in Drosophila melanogaster.

J Biol Rhythms 2019 Apr 2:748730419837767. Epub 2019 Apr 2.

Behavioural Neurogenetics Laboratory, Neurosciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, Karnataka India.

The stability of circadian clock mechanisms under cyclic environments contributes to increased Darwinian fitness by accurately timing daily behavior and physiology. Earlier studies on biological clocks speculated that the timing of behavior and its accuracy are determined by the intrinsic period (τ) of the circadian clock under constant conditions, its stability, the period of the external cycle (T), and resetting of the clock by environmental time cues. However, most of these previous studies suffered from certain limitations, the major ones being a narrow range of examined τ values and a non-uniformity in the genetic background across the individuals tested. Read More

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http://dx.doi.org/10.1177/0748730419837767DOI Listing
April 2019
1 Read

Chrono-Nutrition: The Relationship between Time-of-Day Energy and Macronutrient Intake and Children's Body Weight Status.

J Biol Rhythms 2019 Mar 28:748730419838908. Epub 2019 Mar 28.

EPIUnit - Instituto de Saúde Pública, Universidade do Porto, Rua das Taipas, Porto, Portugal.

The time of eating has been considered to have an important role in weight regulation. However, it is unknown if there are specific daily patterns of energy and macronutrient distribution that could be more beneficial for metabolic outcomes, especially obesity. This study aimed to assess the effect of time-of-day energy and macronutrient intake at 4 y of age on the weight status at 7 y of age. Read More

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http://dx.doi.org/10.1177/0748730419838908DOI Listing

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

J Biol Rhythms 2019 Apr 21;34(2):144-153. Epub 2019 Mar 21.

Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey, UK.

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. Read More

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http://dx.doi.org/10.1177/0748730419836370DOI Listing

Development of the Molecular Circadian Clock and Its Light Sensitivity in Drosophila Melanogaster.

J Biol Rhythms 2019 Mar 18:748730419836818. Epub 2019 Mar 18.

Department of Anaesthesiology, School of Medicine, University of Auckland, Auckland, 1142 New Zealand.

The importance of the circadian clock for the control of behavior and physiology is well established but how and when it develops is not fully understood. Here the initial expression pattern of the key clock gene period was recorded in Drosophila from embryos in vivo, using transgenic luciferase reporters. PERIOD expression in the presumptive central-clock dorsal neurons started to oscillate in the embryo in constant darkness. Read More

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http://dx.doi.org/10.1177/0748730419836818DOI Listing

Development and Entrainment of the Fetal Clock in the Suprachiasmatic Nuclei: The Role of Glucocorticoids.

J Biol Rhythms 2019 Mar 11:748730419835360. Epub 2019 Mar 11.

Department of Neurohumoral Regulations, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.

The adult circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus is resilient to glucocorticoids (GCs). The fetal rodent SCN resembles that of the adult in its organization of GC-sensitive peripheral tissues. We tested the hypothesis that the fetal SCN clock is sensitive to changes in GC levels. Read More

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http://dx.doi.org/10.1177/0748730419835360DOI Listing

Effect of White Light Devoid of "Cyan" Spectrum Radiation on Nighttime Melatonin Suppression Over a 1-h Exposure Duration.

J Biol Rhythms 2019 Apr 1;34(2):195-204. Epub 2019 Mar 1.

Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA.

The intrinsically photosensitive retinal ganglion cells are the main conduit of the light signal emanating from the retina to the biological clock located in the suprachiasmatic nuclei of the hypothalamus. Lighting manufacturers are developing white light sources that are devoid of wavelengths around 480 nm ("cyan gap") to reduce their impact on the circadian system. The present study was designed to investigate whether exposure to a "cyan-gap," 3000 K white light source, spectrally tuned to reduce radiant power between 475 and 495 nm (reducing stimulation of the melanopsin-containing photoreceptor), would suppress melatonin less than a conventional 3000 K light source. Read More

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http://dx.doi.org/10.1177/0748730419830013DOI Listing
April 2019
1 Read

Achilles-Mediated and Sex-Specific Regulation of Circadian mRNA Rhythms in Drosophila.

J Biol Rhythms 2019 Apr 25;34(2):131-143. Epub 2019 Feb 25.

Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA.

The circadian clock is an evolutionarily conserved mechanism that generates the rhythmic expression of downstream genes. The core circadian clock drives the expression of clock-controlled genes, which in turn play critical roles in carrying out many rhythmic physiological processes. Nevertheless, the molecular mechanisms by which clock output genes orchestrate rhythmic signals from the brain to peripheral tissues are largely unknown. Read More

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http://dx.doi.org/10.1177/0748730419830845DOI Listing

Nocturnal Melatonin Suppression by Adolescents and Adults for Different Levels, Spectra, and Durations of Light Exposure.

J Biol Rhythms 2019 Apr 25;34(2):178-194. Epub 2019 Feb 25.

Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA.

The human circadian system is primarily regulated by the 24-h LD cycle incident on the retina, and nocturnal melatonin suppression is a primary outcome measure for characterizing the biological clock's response to those light exposures. A limited amount of data related to the combined effects of light level, spectrum, and exposure duration on nocturnal melatonin suppression has impeded the development of circadian-effective lighting recommendations and light-treatment methods. The study's primary goal was to measure nocturnal melatonin suppression for a wide range of light levels (40 to 1000 lux), 2 white light spectra (2700 K and 6500 K), and an extended range of nighttime light exposure durations (0. Read More

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http://dx.doi.org/10.1177/0748730419828056DOI Listing
April 2019
1 Read

First In Situ Identification of Ultradian and Infradian Rhythms, and Nocturnal Locomotion Activities of Four Colonies of Red Wood Ants ( Formica rufa-Group).

J Biol Rhythms 2019 Feb 14;34(1):19-38. Epub 2019 Jan 14.

Image Analysis Group, Faculty of Electrical Engineering and Information Technology, Technical University of Dortmund, Dortmund, Germany.

In situ activity patterns of 2 Formica rufa-group species ( F. pratensis; F. polyctena) were continuously studied at 4 different red wood-ant nests for 6 months in each of the years 2010, 2011, 2012, and 2016 and related to weather factors and variations in the Earth's magnetic field. Read More

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http://dx.doi.org/10.1177/0748730418821446DOI Listing
February 2019

Sex Moderates Relationships Among School Night Sleep Duration, Social Jetlag, and Depressive Symptoms in Adolescents.

J Biol Rhythms 2019 Apr 18;34(2):205-217. Epub 2019 Feb 18.

Department of Biobehavioral Health, College of Health and Human Development, Pennsylvania State University, University Park, PA, USA.

Social jetlag, a misalignment between sleep timing on the weekend and during the work week, is associated with depressive symptoms among adults across both sexes. A previous study found that later sleep timing was associated with depressive symptoms in women but not men. To date, however, no research has investigated whether the association between social jetlag and depression varies by sex among adolescents. Read More

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http://journals.sagepub.com/doi/10.1177/0748730419828102
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http://dx.doi.org/10.1177/0748730419828102DOI Listing
April 2019
7 Reads

Differential Recovery Speed of Activity and Metabolic Rhythms in Rats After an Experimental Protocol of Shift-Work.

J Biol Rhythms 2019 Apr 15;34(2):154-166. Epub 2019 Feb 15.

Departamento de Fisiología, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México.

The circadian system drives the temporal organization of body physiology in relation to the changing daily environment. Shift-work (SW) disrupts this temporal order and is associated with the loss of homeostasis and metabolic syndrome. In a rodent model of SW based on forced activity in the rest phase for 4 weeks, we describe the occurrence of circadian desynchrony, as well as metabolic and liver dysfunction. Read More

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http://dx.doi.org/10.1177/0748730419828534DOI Listing

CikA Modulates the Effect of KaiA on the Period of the Circadian Oscillation in KaiC Phosphorylation.

J Biol Rhythms 2019 Apr 13;34(2):218-223. Epub 2019 Feb 13.

Department of Chemistry and Environmental Science.

Cyanobacteria contain a circadian oscillator that can be reconstituted in vitro. In the reconstituted circadian oscillator, the phosphorylation state of KaiC oscillates with a circadian period, spending about 12 h in the phosphorylation phase and another 12 h in the dephosphorylation phase. Although some entrainment studies have been performed using the reconstituted oscillator, they were insufficient to fully explain entrainment mechanisms of the cyanobacterial circadian clock due to the lack of input pathway components in the in vitro oscillator reaction mixture. Read More

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http://dx.doi.org/10.1177/0748730419828068DOI Listing

Shift Work Disrupts Circadian Regulation of the Transcriptome in Hospital Nurses.

J Biol Rhythms 2019 Apr 4;34(2):167-177. Epub 2019 Feb 4.

Department of Psychiatry and Behavioral Neurobiology.

Circadian misalignment between sleep and behavioral/feeding rhythms is thought to lead to various health impairments in shift workers. Therefore, we investigated how shift work leads to genome-wide circadian dysregulation in hospital nurses. Female nurses from the University of Alabama at Birmingham (UAB) Hospital working night shift ( n = 9; 29. Read More

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http://dx.doi.org/10.1177/0748730419826694DOI Listing

Effect of Night Time Eating on Postprandial Triglyceride Metabolism in Healthy Adults: A Systematic Literature Review.

J Biol Rhythms 2019 Apr 25;34(2):119-130. Epub 2019 Jan 25.

Department of Nutrition, Dietetics and Food, Monash University, VIC Australia.

Eating at night time, as is frequent in shift workers, may contribute to increased cardiovascular disease (CVD) risk through a disruption in usual lipid metabolism, resulting in repeated and sustained hyperlipidemia at night. This systematic review aimed to investigate the impact of eating a meal at night compared with the same meal eaten during the day on postprandial lipemia. Six databases were searched: CINAHL Plus, Cochrane Library, EMBASE, Ovid MEDLINE, Informit, and SCOPUS. Read More

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http://dx.doi.org/10.1177/0748730418824214DOI Listing

Development-Dependent Changes in the NR2 Subtype of the N-Methyl-D-Aspartate Receptor in the Suprachiasmatic Nucleus of the Rat.

J Biol Rhythms 2019 Feb 17;34(1):39-50. Epub 2019 Jan 17.

Centro Universitario de Investigaciones Biomédicas "CUIB", Universidad de Colima, Colima, Col, Mexico.

The suprachiasmatic nucleus (SCN) is the main brain clock that regulates circadian rhythms in mammals. The SCN synchronizes to the LD cycle through the retinohypothalamic tract (RHT), which projects to ventral SCN neurons via glutamatergic synapses. Released glutamate activates N-methyl-D-aspartate (NMDA) receptors, which play a critical role in the activation of signaling cascades to enable phase shifts. Read More

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http://dx.doi.org/10.1177/0748730418824198DOI Listing
February 2019
1 Read

The Phase-Shifting Effect of Bright Light Exposure on Circadian Rhythmicity in the Human Transcriptome.

J Biol Rhythms 2019 Feb 8;34(1):84-97. Epub 2019 Jan 8.

Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Canada.

Light is a potent synchronizer of the central circadian clock; however, the effect of light exposure on peripheral gene expression is largely unknown. The objective of this study was to explore the effect of bright light exposure on genome-wide peripheral gene expression levels during a 4-day simulated night shift protocol in which the habitual sleep period is delayed by 10 h. Eleven healthy participants (mean age, 24 years; range, 18-30; 10 men/1 woman) were studied under controlled laboratory conditions. Read More

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http://journals.sagepub.com/doi/10.1177/0748730418821776
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http://dx.doi.org/10.1177/0748730418821776DOI Listing
February 2019
2 Reads
2.774 Impact Factor

Novel Light/Dark Regimens with Minimum Light Promote Circadian Disruption: Simulations with a Model Oscillator.

J Biol Rhythms 2019 Feb 31;34(1):105-110. Epub 2018 Dec 31.

Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil.

Artificial lab manipulation of LD cycles has enabled simulations of the disruptive conditions found in modern human societies, such as jet-lag, night-work and light at night. New techniques using animal models have been developed, and these can greatly improve our understanding of circadian disruption. Some of these techniques, such as in vivo bioluminescence assays, require minimum external light. Read More

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http://dx.doi.org/10.1177/0748730418820727DOI Listing
February 2019
1 Read

Diurnality, Type 2 Diabetes, and Depressive-Like Behavior.

J Biol Rhythms 2019 Feb 25;34(1):69-83. Epub 2018 Dec 25.

School of Zoology, Tel-Aviv University, Tel Aviv, Ramat Aviv, Israel.

Although type 2 diabetes (T2DM) and depression are associated with disturbances in circadian rhythms, most studies of these diseases use nocturnal mice and rats while modeling diurnal humans. We suggest that the development of T2DM and depression are related to changes that accompany the switch from the mammalian ancestral nocturnal activity to the current diurnal one. We show that diurnal sand rats ( Psammomys obesus) held outdoors in laboratory cages (where they are exposed to natural environmental conditions) and fed a standard rodent diet do not develop T2DM in contrast to animals held indoors (where the only cycling environmental condition is light) fed the same diet. Read More

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http://journals.sagepub.com/doi/10.1177/0748730418819373
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http://dx.doi.org/10.1177/0748730418819373DOI Listing
February 2019
2 Reads

Phase Shifts to a Moderate Intensity Light Exposure in Older Adults: A Preliminary Report.

J Biol Rhythms 2019 Feb 17;34(1):98-104. Epub 2018 Dec 17.

Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.

Age-related disrupted sleep has been associated with modifications in the timing of endogenous circadian rhythms. There are studies suggesting a decreased sensitivity of the aging circadian pacemaker to light. In this study, we aimed to test whether a moderate illuminance light stimulus would produce significant phase shifts in older adults, and whether those would fall in a range consistent with the illuminance response curve (IRC) we previously reported in older adults. Read More

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http://dx.doi.org/10.1177/0748730418818655DOI Listing
February 2019
1 Read

LimoRhyde: A Flexible Approach for Differential Analysis of Rhythmic Transcriptome Data.

J Biol Rhythms 2019 Feb 25;34(1):5-18. Epub 2018 Nov 25.

Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee.

Unraveling the effects of genetic or environmental perturbations on biological rhythms requires detecting changes in rhythmicity across multiple conditions. Although methods to detect rhythmicity in genome-scale data are well established, methods to detect changes in rhythmicity or changes in average expression between experimental conditions are often ad hoc and statistically unreliable. Here we present LimoRhyde (linear models for rhythmicity, design), a flexible approach for analyzing transcriptome data from circadian systems. Read More

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http://dx.doi.org/10.1177/0748730418813785DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376636PMC
February 2019
2 Reads

Influence of Schizophrenia-Associated Gene Egr3 on Sleep Behavior and Circadian Rhythms in Mice.

J Biol Rhythms 2018 Dec 15;33(6):662-670. Epub 2018 Oct 15.

Department of Basic Medical Sciences, University of Arizona College of Medicine - Phoenix, Phoenix, Arizona.

Up to 80% of people meeting DSM-IV definitions for schizophrenia will exhibit difficulties with sleep, along with a breakdown in circadian entrainment and rhythmicity. The changes to the sleep and circadian systems in this population are thought to be interdependent, as evidenced by the frequent use of the combined term "sleep and circadian rhythm disruption" or "SCRD" to describe their occurrence. To understand links between sleep and circadian problems in the schizophrenia population, we analyzed the duration and rhythmicity of sleep behavior in mice lacking function of the immediate early gene early growth response 3 ( Egr3). Read More

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http://dx.doi.org/10.1177/0748730418803802DOI Listing
December 2018
2 Reads

A Novel Diabetic Mouse Model for Real-Time Monitoring of Clock Gene Oscillation and Blood Pressure Circadian Rhythm.

J Biol Rhythms 2019 Feb 2;34(1):51-68. Epub 2018 Oct 2.

Department of Physiology, University of Kentucky, Lexington, Kentucky.

Diabetic patients have an increased prevalence of blood pressure (BP) circadian rhythm disruption, which is associated with an increased risk of target organ damage and detrimental cardiovascular events. Limited information is available regarding the role of clock genes in the disruption of BP circadian rhythm in diabetes due to the lack of a diabetic animal model that allows real-time monitoring of clock gene oscillation. Here, we generated a novel diabetic db/db-mPer2 mouse model by crossing type 2 diabetic db/db mice with mPer2 knock-in mice. Read More

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http://journals.sagepub.com/doi/10.1177/0748730418803719
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http://dx.doi.org/10.1177/0748730418803719DOI Listing
February 2019
39 Reads
2.774 Impact Factor

Melatonin Administration Methods for Research in Mammals and Birds.

J Biol Rhythms 2018 Dec 24;33(6):567-588. Epub 2018 Sep 24.

University of California, Berkeley, CA, USA.

Endocrine research in animals often entails exogenous hormone administration. Special issues arise when developing administration protocols for hormones with circadian and seasonal periodicity. This article reviews various methods for the exogenous administration of hormones with such periodicities by focusing on melatonin. Read More

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http://journals.sagepub.com/doi/10.1177/0748730418795802
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http://dx.doi.org/10.1177/0748730418795802DOI Listing
December 2018
6 Reads

Closely Related Fruit Fly Species Living at Different Latitudes Diverge in Their Circadian Clock Anatomy and Rhythmic Behavior.

J Biol Rhythms 2018 Dec 11;33(6):602-613. Epub 2018 Sep 11.

Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany.

Recently, we reported differences in the expression pattern of the blue light-sensitive flavoprotein cryptochrome (CRY) and the neuropeptide pigment-dispersing factor (PDF) in the neuronal clock network of high-latitude Drosophila species, belonging to the Drosophila subgenus ( virilis-repleta radiation), compared with cosmopolitan D. melanogaster flies, belonging to the Sophophora subgenus. Alterations in rhythmic patterns of activity due to these differences might have adaptive significance for colonizing high-latitude habitats and, hence, adjusting to long photoperiods. Read More

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http://dx.doi.org/10.1177/0748730418798096DOI Listing
December 2018
1 Read

Investigation of Dose-Response Relationships for Effects of White Light Exposure on Correlates of Alertness and Executive Control during Regular Daytime Working Hours.

J Biol Rhythms 2018 Dec 10;33(6):649-661. Epub 2018 Sep 10.

Human-Technology Interaction, School of Innovation Sciences, Eindhoven University of Technology, Eindhoven, the Netherlands.

To date, it is largely unknown which light settings define the optimum to steer alertness and cognitive control during regular daytime working hours. In the current article, we used a multimeasure approach combined with a relatively large sample size ( N = 60) and a large range of intensity levels (20-2000 lux at eye level) to investigate the dose-dependent relationship between light and correlates of alertness and executive control during regular working hours in the morning and afternoon. Each participant was exposed to a single-intensity light level for 1 h after a 30-min baseline phase (100 lux at the eye) in the morning and afternoon (on separate days) during their daily routine. Read More

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http://dx.doi.org/10.1177/0748730418796438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6236584PMC
December 2018
15 Reads

White Light During Daytime Does Not Improve Alertness in Well-rested Individuals.

J Biol Rhythms 2018 Dec 7;33(6):637-648. Epub 2018 Sep 7.

University of Groningen, Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, Groningen, the Netherlands.

Broad-spectrum light applied during the night has been shown to affect alertness in a dose-dependent manner. The goal of this experiment was to investigate whether a similar relationship could be established for light exposure during daytime. Fifty healthy participants were subjected to a paradigm (0730-1730 h) in which they were intermittently exposed to 1. Read More

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http://dx.doi.org/10.1177/0748730418796036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6236585PMC
December 2018
1 Read

Light, Alertness, and Alerting Effects of White Light: A Literature Overview.

J Biol Rhythms 2018 Dec 7;33(6):589-601. Epub 2018 Sep 7.

Human-Technology Interaction, School of Innovation Sciences, Eindhoven University of Technology, Eindhoven, the Netherlands.

Light is known to elicit non-image-forming responses, such as effects on alertness. This has been reported especially during light exposure at night. Nighttime results might not be translatable to the day. Read More

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http://dx.doi.org/10.1177/0748730418796443DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6236641PMC
December 2018
1 Read

Implicating a Temperature-Dependent Clock in the Regulation of Torpor Bout Duration in Classic Hibernation.

J Biol Rhythms 2018 Dec 7;33(6):626-636. Epub 2018 Sep 7.

Institute for Cellular and Integrative Neurosciences, UPR 3212, Centre National de la Recherche Scientifique (CNRS) and University of Strasbourg, Strasbourg, France.

Syrian hamsters may present 2 types of torpor when exposed to ambient temperatures in the winter season, from 8°C to 22°C (short photoperiod). The first is daily torpor, which is controlled by the master circadian clock of the body, located in the SCN. In this paper, we show that daily torpor bout duration is unchanged over the 8°C to 22°C temperature range, as predicted from the thermal compensation of circadian clocks. Read More

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http://dx.doi.org/10.1177/0748730418797820DOI Listing
December 2018
1 Read

Two Coupled Circadian Oscillators Are Involved in Nonphotic Acceleration of Reentrainment to Shifted Light Cycles in Mice.

J Biol Rhythms 2018 Dec 4;33(6):614-625. Epub 2018 Sep 4.

Department of Chronomedicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.

The onset and offset of an activity band in the circadian behavioral rhythm are known to differentially reentrain to shifted light-dark cycles (LD). Differential reentrainment could be explained by different light responsivities of circadian oscillators underlying these phase-markers. In contrast, reentrainment is accelerated by exposure to nonphotic time cues such as timed wheel-running. Read More

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http://dx.doi.org/10.1177/0748730418796300DOI Listing
December 2018
1 Read

The Phosphorylation of CREB at Serine 133 Is a Key Event for Circadian Clock Timing and Entrainment in the Suprachiasmatic Nucleus.

J Biol Rhythms 2018 Oct 3;33(5):497-514. Epub 2018 Sep 3.

Department of Neuroscience, Ohio State University, Columbus, OH.

Within the suprachiasmatic nucleus (SCN)-the locus of the master circadian clock- transcriptional regulation via the CREB/CRE pathway is implicated in the functioning of the molecular clock timing process, and is a key conduit through which photic input entrains the oscillator. One event driving CRE-mediated transcription is the phosphorylation of CREB at serine 133 (Ser). Indeed, numerous reporter gene assays have shown that an alanine point mutation in Ser reduces CREB-mediated transcription. Read More

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http://dx.doi.org/10.1177/0748730418791713DOI Listing
October 2018
3 Reads

Evidence for a Coupled Oscillator Model of Endocrine Ultradian Rhythms.

J Biol Rhythms 2018 Oct 22;33(5):475-496. Epub 2018 Aug 22.

The Helen Wills Neuroscience Institute, University of California, Berkeley, California.

Whereas long-period temporal structures in endocrine dynamics have been well studied, endocrine rhythms on the scale of hours are relatively unexplored. The study of these ultradian rhythms (URs) has remained nascent, in part, because a theoretical framework unifying ultradian patterns across systems has not been established. The present overview proposes a conceptual coupled oscillator network model of URs in which oscillating hormonal outputs, or nodes, are connected by edges representing the strength of node-node coupling. Read More

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http://dx.doi.org/10.1177/0748730418791423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6425759PMC
October 2018
1 Read

Bootstrapping and Empirical Bayes Methods Improve Rhythm Detection in Sparsely Sampled Data.

J Biol Rhythms 2018 Aug;33(4):339-349

Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois.

There is much interest in using genome-wide expression time series to identify circadian genes. However, the cost and effort of such measurements often limit data collection. Consequently, it is difficult to assess the experimental uncertainty in the measurements and, in turn, to detect periodic patterns with statistical confidence. Read More

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http://dx.doi.org/10.1177/0748730418789536DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6347739PMC
August 2018
2 Reads

Model-based Inference of a Directed Network of Circadian Neurons.

J Biol Rhythms 2018 Oct 7;33(5):515-522. Epub 2018 Aug 7.

University of California, Santa Barbara, California.

The suprachiasmatic nucleus (SCN) is the master clock of the brain. It is a network of neurons that behave like biological oscillators, capable of synchronizing and maintaining daily rhythms. The detailed structure of this network is still unknown, and the role that the connectivity pattern plays in the network's ability to generate robust oscillations has yet to be fully elucidated. Read More

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http://dx.doi.org/10.1177/0748730418790402DOI Listing
October 2018
1 Read

Circadian-based Treatment Strategy Effective in the BACHD Mouse Model of Huntington's Disease.

J Biol Rhythms 2018 Oct 7;33(5):535-554. Epub 2018 Aug 7.

Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California, USA.

Huntington's disease (HD) patients suffer from progressive neurodegeneration that results in cognitive, psychiatric, cardiovascular, and motor dysfunction. Disturbances in sleep-wake cycles are common among HD patients with reports of delayed sleep onset, frequent bedtime awakenings, and excessive fatigue. The BACHD mouse model exhibits many HD core symptoms including circadian dysfunction. Read More

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http://dx.doi.org/10.1177/0748730418790401DOI Listing
October 2018
1 Read
2.774 Impact Factor

Changes in Accident & Emergency Visits and Return Visits in Relation to the Enforcement of Daylight Saving Time and Photoperiod.

J Biol Rhythms 2018 Oct 30;33(5):555-564. Epub 2018 Jul 30.

Department of Medicine, University of Padova, Padova, Italy.

Daylight saving time (DST) is a source of circadian disruption impinging on millions of people every year. Our aim was to assess modifications, if any, in the number, type, and outcome of Accident & Emergency (A&E) visits/return visits over the DST months. The study included 366,527 visits and 84,380 return visits to the A&E of Padova hospital (Northern Italy) over 3 periods between the years 2007 and 2016: period 1 (2 weeks prior to DST to 19 weeks after), period 2 (2 weeks prior to the return to "winter time" to 4 weeks after), and period 3 (5 consecutive non-DST weeks). Read More

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http://dx.doi.org/10.1177/0748730418791097DOI Listing
October 2018
3 Reads

Circadian Health and Light: A Report on the National Heart, Lung, and Blood Institute's Workshop.

J Biol Rhythms 2018 Oct 23;33(5):451-457. Epub 2018 Jul 23.

Center for Circadian and Sleep Medicine, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.

Despite the omnipresence of artificial and natural light exposure, there exists little guidance in the United States and elsewhere on light exposure in terms of timing, intensity, spectrum, and other light characteristics known to affect human health, performance, and well-being; in parallel, there is little information regarding the quantity and characteristics of light exposure that people receive. To address this, the National Center on Sleep Disorders Research, in the Division of Lung Diseases, National Heart, Lung, and Blood Institute, held a workshop in August 2016 on circadian health and light. Workshop participants discussed scientific research advances on the effects of light on human physiology, identified remaining knowledge gaps in these research areas, and articulated opportunities to use appropriate lighting to protect and improve circadian-dependent health. Read More

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http://dx.doi.org/10.1177/0748730418789506DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414068PMC
October 2018
13 Reads

Caffeine Delays Light-entrained Activity and Potentiates Circadian Photic Phase-resetting in Mice.

J Biol Rhythms 2018 Oct 23;33(5):523-534. Epub 2018 Jul 23.

Indiana University of Pennsylvania, Indiana, Pennsylvania.

Caffeine is widely used to reduce sedation and increase alertness. However, long-term caffeine use may disrupt circadian (daily, 24-h) rhythms and thereby negatively affect health. Here, we examined the effect of caffeine on photic regulation of circadian activity rhythms in mice. Read More

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http://dx.doi.org/10.1177/0748730418789236DOI Listing
October 2018
4 Reads

The Mysterious Food-Entrainable Oscillator: Insights from Mutant and Engineered Mouse Models.

J Biol Rhythms 2018 Oct 23;33(5):458-474. Epub 2018 Jul 23.

Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas.

The food-entrainable oscillator (FEO) is a mysterious circadian clock because its anatomical location(s) and molecular timekeeping mechanism are unknown. Food anticipatory activity (FAA), which is defined as the output of the FEO, emerges during temporally restricted feeding. FAA disappears immediately during ad libitum feeding and reappears during subsequent fasting. Read More

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http://dx.doi.org/10.1177/0748730418789043DOI Listing
October 2018
1 Read

Spectral Tuning of White Light Allows for Strong Reduction in Melatonin Suppression without Changing Illumination Level or Color Temperature.

J Biol Rhythms 2018 Aug 9;33(4):420-431. Epub 2018 Jul 9.

Philips Lighting Research, Department Lighting Applications, Eindhoven, The Netherlands.

Studies with monochromatic light stimuli have shown that the action spectrum for melatonin suppression exhibits its highest sensitivity at short wavelengths, around 460 to 480 nm. Other studies have demonstrated that filtering out the short wavelengths from white light reduces melatonin suppression. However, this filtering of short wavelengths was generally confounded with reduced light intensity and/or changes in color temperature. Read More

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http://dx.doi.org/10.1177/0748730418784041DOI Listing
August 2018
4 Reads

Functional Significance of the Excitatory Effects of GABA in the Suprachiasmatic Nucleus.

J Biol Rhythms 2018 Aug 5;33(4):376-387. Epub 2018 Jul 5.

Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA.

Over 90% of neurons within the suprachiasmatic nucleus (SCN) express γ-aminobutyric acid (GABA). Although GABA is primarily an inhibitory neurotransmitter, in vitro studies suggest that the activation of GABA receptors (GABAR) elicits excitation in the adult SCN. The ratio of excitatory to inhibitory responses to GABA depends on the balance of chloride influx by Na-K-Cl cotransporter 1 (NKCC1) and chloride efflux by K-Cl cotransporters (KCCs). Read More

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http://dx.doi.org/10.1177/0748730418782820DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6419757PMC
August 2018
3 Reads

Musicians' Natural Frequencies of Performance Display Optimal Temporal Stability.

J Biol Rhythms 2018 Aug 25;33(4):432-440. Epub 2018 Jun 25.

Department of Psychology, McGill University, Montreal, QC, Canada.

Many human action sequences, such as speaking and performing music, are inherently rhythmic: Sequence events are produced at quasi-regular temporal intervals. A wide range of interindividual variation has been noted in spontaneous production rates of these rhythmic action sequences. Dynamical theories of motor coordination suggest that individuals spontaneously produce rhythmic sequences at a natural frequency characterized by minimal energy expenditure and maximal temporal stability, relative to other frequencies. Read More

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http://dx.doi.org/10.1177/0748730418783651DOI Listing
August 2018
1 Read

Aging Alters Circadian Rhythms in the Mouse Eye.

J Biol Rhythms 2018 Aug 25;33(4):441-445. Epub 2018 Jun 25.

Department of Pharmacology & Toxicology, Morehouse School of Medicine, Atlanta, Georgia.

The eye contains a circadian system that acts independently from the master circadian clock located in the brain. This circadian system regulates important physiological functions within the eye. Emerging experimental evidence also indicates that disruption of the ocular circadian clock, or its outputs, negatively affects the overall health of the eye. Read More

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http://dx.doi.org/10.1177/0748730418783648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6398161PMC
August 2018
1 Read

Rapid Response and Slow Recovery of the H3K4me3 Epigenomic Marker in the Liver after Light-mediated Phase Advances of the Circadian Clock.

J Biol Rhythms 2018 Aug 11;33(4):363-375. Epub 2018 Jun 11.

Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon.

Mammalian tissues display circadian rhythms in transcription, translation, and histone modifications. Here we asked how an advance of the light-dark cycle alters daily rhythms in the liver epigenome at the H3K4me3 (trimethylation of lysine 4 on histone 3) modification, which is found at active and poised gene promoters. H3K4me3 levels were first measured at 4 time points (zeitgeber time [ZT] 3, 8, 15, and 20) during a normal 12L:12D light-dark cycle. Read More

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http://dx.doi.org/10.1177/0748730418779958DOI Listing
August 2018
25 Reads

Seasonal Changes in Endocannabinoid Concentrations between Active and Hibernating Marmots (Marmota flaviventris).

J Biol Rhythms 2018 Aug 4;33(4):388-401. Epub 2018 Jun 4.

2. University of California, Riverside, California.

Hibernation is a naturally occurring model for studying diseases such as obesity and osteoporosis. Hibernators, marmots (Marmota flaviventris) among them, are able to nearly double their body mass by increasing fat stores prior to hibernation without the negative consequences of obesity. They are also physically inactive for extended periods of time without experiencing negative effects on the skeleton. Read More

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http://dx.doi.org/10.1177/0748730418777660DOI Listing
August 2018
8 Reads

Regulation of Pol II Pausing Is Involved in Daily Gene Transcription in the Mouse Liver.

J Biol Rhythms 2018 Aug 30;33(4):350-362. Epub 2018 May 30.

1. These authors contributed equally to this work.

The circadian clock orchestrates gene expression rhythms. Regulation at the level of gene transcription is essential for molecular and cellular rhythms. Pol II pause release is a critical step of transcription regulation. Read More

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http://dx.doi.org/10.1177/0748730418779526DOI Listing
August 2018
3 Reads

Obesity Disrupts Rhythmic Clock Gene Expression in Maternal Adipose Tissue during Rat Pregnancy.

J Biol Rhythms 2018 06;33(3):289-301

School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia.

Obesity during pregnancy causes numerous maternal and fetal health complications, but the underlying mechanisms remain unclear. Adipose tissue dysfunction in obesity has previously been linked to disruption of the intrinsic adipose clock gene network that is crucial for normal metabolic function. This adipose clock also undergoes major change as part of the maternal metabolic adaptation to pregnancy, but whether this is affected by maternal obesity is unknown. Read More

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http://dx.doi.org/10.1177/0748730418772499DOI Listing
June 2018
2 Reads