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https://www.readbyqxmd.com/read/28333377/circadian-rhythms-in-adipose-tissue-physiology
#1
Jana-Thabea Kiehn, Anthony H Tsang, Isabel Heyde, Brinja Leinweber, Isa Kolbe, Alexei Leliavski, Anthony H Tsang
The different types of adipose tissues fulfill a wide range of biological functions-from energy storage to hormone secretion and thermogenesis-many of which show pronounced variations over the course of the day. Such 24-h rhythms in physiology and behavior are coordinated by endogenous circadian clocks found in all tissues and cells, including adipocytes. At the molecular level, these clocks are based on interlocked transcriptional-translational feedback loops comprised of a set of clock genes/proteins. Tissue-specific clock-controlled transcriptional programs translate time-of-day information into physiologically relevant signals...
March 16, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28321642/circadian-rhythm-dysregulation-in-bipolar-spectrum-disorders
#2
REVIEW
Lauren B Alloy, Tommy H Ng, Madison K Titone, Elaine M Boland
PURPOSE OF REVIEW: We review recent evidence for circadian rhythm dysregulation in bipolar spectrum disorders (BSDs). We examine evidence for endogenous abnormalities in the biological clock and disruptions in the external entrainment of circadian rhythms in BSDs. We also address whether circadian dysregulation provides vulnerability to onset of BSD and evidence for a new integration of reward and circadian dysregulation in BSD. RECENT FINDINGS: Relative circadian phase delay (e...
April 2017: Current Psychiatry Reports
https://www.readbyqxmd.com/read/28306731/correction-a-molecular-clock-infers-heterogeneous-tissue-age-among-patients-with-barrett-s-esophagus
#3
(no author information available yet)
[This corrects the article DOI: 10.1371/journal.pcbi.1004919.].
March 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28303945/dependence-of-nighttime-sleep-duration-in-one-month-old-infants-on-alterations-in-natural-and-artificial-photoperiod
#4
Sachiko Iwata, Fumie Fujita, Masahiro Kinoshita, Mitsuaki Unno, Takashi Horinouchi, Seiichi Morokuma, Osuke Iwata
Human sleep-wake cycles are entrained by both natural and artificial light-dark cycles. However, little is known regarding when and how the photoperiod changes entrain the biological clock after conception. To investigate the dependence of sleep patterns in young infants on the natural and artificial light-dark cycles, 1,302 pairs of one-month-old infants and their mothers were asked to answer a questionnaire. Birth in spring, longer daytime sleep duration, early/regular light-off times, and longer maternal nighttime sleep duration were identified as independent variables for longer infant nighttime sleep duration in both univariate and multivariate analyses...
March 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28302851/structural-basis-of-the-day-night-transition-in-a-bacterial-circadian-clock
#5
Roger Tseng, Nicolette F Goularte, Archana Chavan, Jansen Luu, Susan E Cohen, Yong-Gang Chang, Joel Heisler, Sheng Li, Alicia K Michael, Sarvind Tripathi, Susan S Golden, Andy LiWang, Carrie L Partch
Circadian clocks are ubiquitous timing systems that induce rhythms of biological activities in synchrony with night and day. In cyanobacteria, timing is generated by a posttranslational clock consisting of KaiA, KaiB, and KaiC proteins and a set of output signaling proteins, SasA and CikA, which transduce this rhythm to control gene expression. Here, we describe crystal and nuclear magnetic resonance structures of KaiB-KaiC,KaiA-KaiB-KaiC, and CikA-KaiB complexes. They reveal how the metamorphic properties of KaiB, a protein that adopts two distinct folds, and the post-adenosine triphosphate hydrolysis state of KaiC create a hub around which nighttime signaling events revolve, including inactivation of KaiA and reciprocal regulation of the mutually antagonistic signaling proteins, SasA and CikA...
March 17, 2017: Science
https://www.readbyqxmd.com/read/28296892/blue-light-induced-accumulation-of-reactive-oxygen-species-is-a-consequence-of-the-drosophila-cryptochrome-photocycle
#6
Louis-David Arthaut, Nathalie Jourdan, Ali Mteyrek, Maria Procopio, Mohamed El-Esawi, Alain d'Harlingue, Pierre-Etienne Bouchet, Jacques Witczak, Thorsten Ritz, André Klarsfeld, Serge Birman, Robert J Usselman, Ute Hoecker, Carlos F Martino, Margaret Ahmad
Cryptochromes are evolutionarily conserved blue-light absorbing flavoproteins which participate in many important cellular processes including in entrainment of the circadian clock in plants, Drosophila and humans. Drosophila melanogaster cryptochrome (DmCry) absorbs light through a flavin (FAD) cofactor that undergoes photoreduction to the anionic radical (FAD•-) redox state both in vitro and in vivo. However, recent efforts to link this photoconversion to the initiation of a biological response have remained controversial...
2017: PloS One
https://www.readbyqxmd.com/read/28288095/trypanosoma-brucei-metabolism-is-under-circadian-control
#7
Filipa Rijo-Ferreira, Daniel Pinto-Neves, Nuno L Barbosa-Morais, Joseph S Takahashi, Luisa M Figueiredo
The Earth's rotation forced life to evolve under cyclic day and night environmental changes. To anticipate such daily cycles, prokaryote and eukaryote free-living organisms evolved intrinsic clocks that regulate physiological and behavioural processes. Daily rhythms have been observed in organisms living within hosts, such as parasites. Whether parasites have intrinsic molecular clocks or whether they simply respond to host rhythmic physiological cues remains unknown. Here, we show that Trypanosoma brucei, the causative agent of human sleeping sickness, has an intrinsic circadian clock that regulates its metabolism in two different stages of the life cycle...
March 13, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/28276426/microrna-92a-is-a-circadian-modulator-of-neuronal-excitability-in-drosophila
#8
Xiao Chen, Michael Rosbash
Many biological and behavioural processes of animals are governed by an endogenous circadian clock, which is dependent on transcriptional regulation. Here we address post-transcriptional regulation and the role of miRNAs in Drosophila circadian rhythms. At least six miRNAs show cycling expression levels within the pigment dispersing factor (PDF) cell-pacemaker neurons; only mir-92a peaks during the night. In vivo calcium monitoring, dynamics of PDF projections, ArcLight, GCaMP6 imaging and sleep assays indicate that mir-92a suppresses neuronal excitability...
March 9, 2017: Nature Communications
https://www.readbyqxmd.com/read/28265565/the-draft-genome-and-transcriptome-of-the-atlantic-horseshoe-crab-limulus-polyphemus
#9
Stephen D Simpson, Jordan S Ramsdell, Winsor H Watson Iii, Christopher C Chabot
The horseshoe crab, Limulus polyphemus, exhibits robust circadian and circatidal rhythms, but little is known about the molecular mechanisms underlying those rhythms. In this study, horseshoe crabs were collected during the day and night as well as high and low tides, and their muscle and central nervous system tissues were processed for genome and transcriptome sequencing, respectively. The genome assembly resulted in 7.4 × 10(5) contigs with N50 of 4,736, while the transcriptome assembly resulted in 9.3 × 10(4) contigs and N50 of 3,497...
2017: International Journal of Genomics
https://www.readbyqxmd.com/read/28243223/retinoid-x-receptors-intersect-the-molecular-clockwork-in-the-regulation-of-liver-metabolism
#10
REVIEW
Salvatore De Cosmo, Gianluigi Mazzoccoli
Liver metabolic pathways are driven by the biological clock, and appropriate timing of 24-h patterns of metabolic gene expression as well as anabolic/catabolic processes with wake-related activity/feeding and sleep-related resting/fasting cycles preserves hepatic healthiness. The interplay among the liver metabolic pathways and the molecular clockwork is geared by the nuclear receptors, and ligand-dependent transcription factors that gauge the cellular nutritional status and redox balance, bind hormones and metabolites, and modulate the transcription of thousands target genes through their DNA-binding domain...
2017: Frontiers in Endocrinology
https://www.readbyqxmd.com/read/28241858/machine-learning-identifies-a-compact-gene-set-for-monitoring-the-circadian-clock-in-human-blood
#11
Jacob J Hughey
BACKGROUND: The circadian clock and the daily rhythms it produces are crucial for human health, but are often disrupted by the modern environment. At the same time, circadian rhythms may influence the efficacy and toxicity of therapeutics and the metabolic response to food intake. Developing treatments for circadian dysfunction, as well as optimizing the daily timing of treatments for other health conditions, will require a simple and accurate method to monitor the molecular state of the circadian clock...
February 28, 2017: Genome Medicine
https://www.readbyqxmd.com/read/28229310/diagnosis-and-treatment-of-non-24-h-sleep-wake-disorder-in-the-blind
#12
REVIEW
Jonathan S Emens, Charmane I Eastman
Non-24-h sleep-wake disorder (non-24) is a circadian rhythm disorder occurring in 55-70% of totally blind individuals (those lacking conscious light perception) in which the 24-h biological clock (central, hypothalamic, circadian pacemaker) is no longer synchronized, or entrained, to the 24-h day. Instead, the overt rhythms controlled by the biological clock gradually shift progressively earlier or later (free run) in accordance with the clock's near-24-h period, resulting in a recurrent pattern of daytime hypersomnolence and night-time insomnia...
February 22, 2017: Drugs
https://www.readbyqxmd.com/read/28226198/olanzapine-induced-early-cardiovascular-effects-are-mediated-by-the-biological-clock-and-prevented-by-melatonin
#13
Francisco Romo-Nava, Frederik N Buijs, Marcela Valdés-Tovar, Gloria Benítez-King, MariCarmen Basualdo, Mercedes Perusquía, Gerhard Heinze, Carolina Escobar, Ruud M Buijs
Second generation antipsychotics (SGA) are associated with adverse cardiometabolic side-effects contributing to premature mortality in patients. While mechanisms mediating these cardiometabolic side-effects remain poorly understood, three independent studies recently demonstrated that melatonin was protective against cardiometabolic risk in SGA-treated patients. Since one of the main target areas of circulating melatonin in the brain is the suprachiasmatic nucleus (SCN), we hypothesized that the SCN is involved in SGA-induced early cardiovascular effects in Wistar rats...
February 22, 2017: Journal of Pineal Research
https://www.readbyqxmd.com/read/28223912/diet-induced-obesity-and-circadian-disruption-of-feeding-behavior
#14
REVIEW
Aurea Blancas-Velazquez, Jorge Mendoza, Alexandra N Garcia, Susanne E la Fleur
Feeding behavior shows a rhythmic daily pattern, which in nocturnal rodents is observed mainly during the dark period. This rhythmicity is under the influence of the hypothalamic suprachiasmatic nucleus (SCN), the main biological clock. Nevertheless, various studies have shown that in rodent models of obesity, using high-energy diets, the general locomotor activity and feeding rhythms can be disrupted. Here, we review the data on the effects of diet-induced obesity (DIO) on locomotor activity and feeding patterns, as well as the effect on the brain sites within the neural circuitry involved in metabolic and rewarding feeding behavior...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28222291/circadian-rhythms-the-price-of-electric-light
#15
Jonathan S Emens
A new study demonstrates that modern electric lighting has caused the near-24-hour biological clock to be set to a later time and that humans physiologically respond to seasonal changes in day length under conditions of natural light exposure.
February 20, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28220104/systems-biology-derived-discoveries-of-intrinsic-clocks
#16
REVIEW
Arthur Millius, Hiroki R Ueda
A systems approach to studying biology uses a variety of mathematical, computational, and engineering tools to holistically understand and model properties of cells, tissues, and organisms. Building from early biochemical, genetic, and physiological studies, systems biology became established through the development of genome-wide methods, high-throughput procedures, modern computational processing power, and bioinformatics. Here, we highlight a variety of systems approaches to the study of biological rhythms that occur with a 24-h period-circadian rhythms...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28216658/timing-the-day-what-makes-bacterial-clocks-tick
#17
REVIEW
Carl Hirschie Johnson, Chi Zhao, Yao Xu, Tetsuya Mori
Chronobiological studies of prokaryotic organisms have generally lagged far behind the study of endogenous circadian clocks in eukaryotes, in which such systems are essentially ubiquitous. However, despite only being studied during the past 25 years, cyanobacteria have become important model organisms for the study of circadian rhythms and, presently, their timekeeping mechanism is the best understood of any system in terms of biochemistry, structural biology, biophysics and adaptive importance. Nevertheless, intrinsic daily rhythmicity among bacteria other than cyanobacteria is essentially unknown; some tantalizing information suggests widespread daily timekeeping among Eubacteria and Archaea through mechanisms that share common elements with the cyanobacterial clock but are distinct...
April 2017: Nature Reviews. Microbiology
https://www.readbyqxmd.com/read/28199106/mechanistic-studies-of-the-photoinduced-quinone-trimethyl-lock-decaging-process
#18
Clinton J Regan, David P Walton, Oliver S Shafaat, Dennis A Dougherty
Mechanistic studies of a general reaction that decages a wide range of substrates on exposure to visible light are described. The reaction involves a photochemically initiated reduction of a quinone mediated by an appended thioether. After reduction, a trimethyl lock system incorporated into the quinone leads to thermal decaging. The reaction could be viewed as an electron-transfer initiated reduction of the quinone or as a hydrogen abstraction-Norrish Type II-reaction. Product analysis, kinetic isotope effects, stereochemical labeling, radical clock, and transient absorption studies support the electron transfer mechanism...
March 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28186138/the-spectral-and-spatial-distribution-of-light-pollution-in-the-waters-of-the-northern-gulf-of-aqaba-eilat
#19
Raz Tamir, Amit Lerner, Carynelisa Haspel, Zvy Dubinsky, David Iluz
The urbanization of the shores of the Gulf of Aqaba has exposed the marine environment there, including unique fringing coral reefs, to strong anthropogenic light sources. Here we present the first in situ measurements of artificial nighttime light under water in such an ecosystem, with irradiance measured in 12 wavelength bands, at 19 measurement stations spread over 44 square km, and at 30 depths down to 30-m depth. At 1-m depth, we find downwelling irradiance values that vary from 4.6 × 10(-4) μW cm(-2) nm(-1) 500 m from the city to 1 × 10(-6) μW cm(-2) nm(-1) in the center of the gulf (9...
February 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28185583/probabilistic-inference-of-lateral-gene-transfer-events
#20
Mehmood Alam Khan, Owais Mahmudi, Ikram Ullah, Lars Arvestad, Jens Lagergren
BACKGROUND: Lateral gene transfer (LGT) is an evolutionary process that has an important role in biology. It challenges the traditional binary tree-like evolution of species and is attracting increasing attention of the molecular biologists due to its involvement in antibiotic resistance. A number of attempts have been made to model LGT in the presence of gene duplication and loss, but reliably placing LGT events in the species tree has remained a challenge. RESULTS: In this paper, we propose probabilistic methods that samples reconciliations of the gene tree with a dated species tree and computes maximum a posteriori probabilities...
November 11, 2016: BMC Bioinformatics
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