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Biological clock

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https://www.readbyqxmd.com/read/28527179/making-time-conservation-of-biological-clocks-from-fungi-to-animals
#1
Jay C Dunlap, Jennifer J Loros
The capacity for biological timekeeping arose at least three times through evolution, in prokaryotic cyanobacteria, in cells that evolved into higher plants, and within the group of organisms that eventually became the fungi and the animals. Neurospora is a tractable model system for understanding the molecular bases of circadian rhythms in the last of these groups, and is perhaps the most intensively studied circadian cell type. Rhythmic processes described in fungi include growth rate, stress responses, developmental capacity, and sporulation, as well as much of metabolism; fungi use clocks to anticipate daily environmental changes...
May 2017: Microbiology Spectrum
https://www.readbyqxmd.com/read/28525248/-magnetic-fields-and-health-from-epidemiology-to-cryptochrome-chemistry
#2
REVIEW
J Vanderstraeten
Biological effects of static magnetic fields (MF) and time-varying MF of electricity (50/60 Hz) appear possible from intensities in the low illitesla range. However, prolonged exposure to 50/60 Hz MF is associated with an increased risk of childhood leukemia at less than one microtesla of time-averaged intensity. And such kind of association is suggested in adults for some blood cancers and senile dementia. The cryptochrome hypothesis has been proposed to explain the association established with childhood leukemia...
2017: Revue Médicale de Bruxelles
https://www.readbyqxmd.com/read/28506121/mammalian-circadian-period-but-not-phase-and-amplitude-is-robust-against-redox-and-metabolic-perturbations
#3
Marrit Putker, Priya Crosby, Kevin A Feeney, Nathaniel P Hoyle, Ana S H da Costa, Edoardo Gaude, Christian Frezza, John Stuart O'Neill
AIMS: Circadian rhythms permeate all levels of biology to temporally regulate cell and whole-body physiology, although the cell-autonomous mechanism that confers ~24-hour periodicity is incompletely understood. Reports describing circadian oscillations of over-oxidised peroxiredoxin abundance have suggested redox signaling plays an important role in the timekeeping mechanism. Here, we tested the functional contribution that redox state and primary metabolism make to mammalian cellular timekeeping...
May 15, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28503212/associations-between-maternal-risk-factors-of-adverse-pregnancy-and-birth-outcomes-and-the-offspring-epigenetic-clock-of-gestational-age-at-birth
#4
Polina Girchenko, Jari Lahti, Darina Czamara, Anna K Knight, Meaghan J Jones, Anna Suarez, Esa Hämäläinen, Eero Kajantie, Hannele Laivuori, Pia M Villa, Rebecca M Reynolds, Michael S Kobor, Alicia K Smith, Elisabeth B Binder, Katri Räikkönen
BACKGROUND: A recent study has shown that it is possible to accurately estimate gestational age (GA) at birth from the DNA methylation (DNAm) of fetal umbilical cord blood/newborn blood spots. This DNAm GA predictor may provide additional information relevant to developmental stage. In 814 mother-neonate pairs, we evaluated the associations between DNAm GA and a number of maternal and offspring characteristics. These characteristics reflect prenatal environmental adversity and are expected to influence newborn developmental stage...
2017: Clinical Epigenetics
https://www.readbyqxmd.com/read/28503165/stress-related-and-circadian-secretion-and-target-tissue-actions-of-glucocorticoids-impact-on-health
#5
REVIEW
Nicolas C Nicolaides, Evangelia Charmandari, Tomoshige Kino, George P Chrousos
Living organisms are highly complex systems that must maintain a dynamic equilibrium or homeostasis that requires energy to be sustained. Stress is a state in which several extrinsic or intrinsic disturbing stimuli, the stressors, threaten, or are perceived as threatening, homeostasis. To achieve homeostasis against the stressors, organisms have developed a highly sophisticated system, the stress system, which provides neuroendocrine adaptive responses, to restore homeostasis. These responses must be appropriate in terms of size and/or duration; otherwise, they may sustain life but be associated with detrimental effects on numerous physiologic functions of the organism, leading to a state of disease-causing disturbed homeostasis or cacostasis...
2017: Frontiers in Endocrinology
https://www.readbyqxmd.com/read/28503116/melatonin-pharmacology-functions-and-therapeutic-benefits
#6
REVIEW
Sylvie Tordjman, Sylvie Chokron, Richard Delorme, Annaëlle Charrier, Eric Bellissant, Nemat Jaafari, Claire Fougerou
BACKGROUND: Melatonin synchronizes central but also peripheral oscillators (fetal adrenal gland, pancreas, liver, kidney, heart, lung, fat, gut, etc.), allowing temporal organization of biological functions through circadian rhythms (24-hour cycles) in relation to periodic environmental changes and therefore adaptation of the individual to his/her internal and external environment. Measures of melatonin are considered the best peripheral indices of human circadian timing based on an internal 24-hour clock...
April 2017: Current Neuropharmacology
https://www.readbyqxmd.com/read/28496429/molecular-mechanisms-regulating-temperature-compensation-of-the-circadian-clock
#7
REVIEW
Rajesh Narasimamurthy, David M Virshup
An approximately 24-h biological timekeeping mechanism called the circadian clock is present in virtually all light-sensitive organisms from cyanobacteria to humans. The clock system regulates our sleep-wake cycle, feeding-fasting, hormonal secretion, body temperature, and many other physiological functions. Signals from the master circadian oscillator entrain peripheral clocks using a variety of neural and hormonal signals. Even centrally controlled internal temperature fluctuations can entrain the peripheral circadian clocks...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28496287/a-systems-theoretic-approach-to-analysis-and-control-of-mammalian-circadian-dynamics
#8
John H Abel, Francis J Doyle
The mammalian circadian clock is a complex multi-scale, multivariable biological control system. In the past two decades, methods from systems engineering have led to numerous insights into the architecture and functionality of this system. In this review, we examine the mammalian circadian system through a process systems lens. We present a mathematical framework for examining the cellular circadian oscillator, and show recent extensions for understanding population-scale dynamics. We provide an overview of the routes by which the circadian system can be systemically manipulated, and present in silico proof of concept results for phase resetting of the clock via model predictive control...
December 2016: Chemical Engineering Research & Design: Transactions of the Institution of Chemical Engineers
https://www.readbyqxmd.com/read/28487255/disruption-of-adolescents-circadian-clock-the-vicious-circle-of-media-use-exposure-to-light-at-night-sleep-loss-and-risk-behaviors
#9
Yvan Touitou, David Touitou, Alain Reinberg
Although sleep is a key element in adolescent development, teens are spending increasing amounts of time online with health risks related to excessive use of electronic media (computers, smartphones, tablets, consoles…) negatively associated with daytime functioning and sleep outcomes. Adolescent sleep becomes irregular, shortened and delayed in relation with later sleep onset and early waking time due to early school starting times on weekdays which results in rhythm desynchronization and sleep loss. In addition, exposure of adolescents to the numerous electronic devices prior to bedtime has become a great concern because LEDs emit much more blue light than white incandescent bulbs and compact fluorescent bulbs and have therefore a greater impact on the biological clock...
May 12, 2017: Journal of Physiology, Paris
https://www.readbyqxmd.com/read/28486416/transcriptomics-and-the-mediterranean-diet-a-systematic-review
#10
REVIEW
Luis V Herrera-Marcos, José M Lou-Bonafonte, Carmen Arnal, María A Navarro, Jesús Osada
The Mediterranean diet has been proven to be highly effective in the prevention of cardiovascular diseases and cancer and in decreasing overall mortality. Nowadays, transcriptomics is gaining particular relevance due to the existence of non-coding RNAs capable of regulating many biological processes. The present work describes a systematic review of current evidence supporting the influence of the Mediterranean diet on transcriptomes of different tissues in various experimental models. While information on regulatory RNA is very limited, they seem to contribute to the effect...
May 9, 2017: Nutrients
https://www.readbyqxmd.com/read/28486120/circadian-rhythms-move-over-neurons-astrocytes-mediate-scn-clock-function
#11
Marc D Ruben, John B Hogenesch
Neurons in the suprachiasmatic nuclei (SCN) of the hypothalamus are described as master pacemaker cells for biological rhythms. However, a series of recent studies demonstrate the importance of another cell type, astrocytes, for biological timekeeping.
May 8, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28475596/long-term-rebaudioside-a-treatment-does-not-alter-circadian-activity-rhythms-adiposity-or-insulin-action-in-male-mice
#12
Thomas H Reynolds, Rachelle A Soriano, Obadi A Obadi, Stanley Murkland, Bernard Possidente
Obesity is a major public health problem that is highly associated with insulin resistance and type 2 diabetes, two conditions associated with circadian disruption. To date, dieting is one of the only interventions that result in substantial weight loss, but restricting caloric intake is difficult to maintain long-term. The use of artificial sweeteners, particularly in individuals that consume sugar sweetened beverages (energy drinks, soda), can reduce caloric intake and possibly facilitate weight loss. The purpose of the present study was to examine the effects of the artificial sweetener, rebaudioside A (Reb-A), on circadian rhythms, in vivo insulin action, and the susceptibility to diet-induced obesity...
2017: PloS One
https://www.readbyqxmd.com/read/28473844/functional-characterization-of-a-putative-glycine-max-elf4-in-transgenic-arabidopsis-and-its-role-during-flowering-control
#13
Juliana Marcolino-Gomes, Thiago J Nakayama, Hugo B C Molinari, Marcos F Basso, Liliane M M Henning, Renata Fuganti-Pagliarini, Frank G Harmon, Alexandre L Nepomuceno
Flowering is an important trait in major crops like soybean due to its direct relation to grain production. The circadian clock mediates the perception of seasonal changes in day length and temperature to modulate flowering time. The circadian clock gene EARLY FLOWERING 4 (ELF4) was identified in Arabidopsis thaliana and is believed to play a key role in the integration of photoperiod, circadian regulation, and flowering. The molecular circuitry that comprises the circadian clock and flowering control in soybeans is just beginning to be understood...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28471941/basic-science-and-pathogenesis-of-ageing-with-hiv-potential-mechanisms-and-biomarkers
#14
Claire Lagathu, Andrea Cossarizza, Véronique Béréziat, Milena Nasi, Jacqueline Capeau, Marcello Pinti
: The increased prevalence of age-related comorbidities and mortality is worrisome in ageing HIV-infected patients. Here, we aim to analyse the different ageing mechanisms with regard to HIV infection. Ageing results from the time-dependent accumulation of random cellular damage. Epigenetic modifications and mitochondrial DNA haplogroups modulate ageing. In antiretroviral treatment-controlled patients, epigenetic clock appears to be advanced, and some haplogroups are associated with HIV infection severity. Telomere shortening is enhanced in HIV-infected patients because of HIV and some nucleoside analogue reverse transcriptase inhibitors...
June 1, 2017: AIDS
https://www.readbyqxmd.com/read/28469414/the-synergistic-role-of-light-feeding-phase-relations-on-entraining-robust-circadian-rhythms-in-the-periphery
#15
Seul-A Bae, Ioannis P Androulakis
The feeding and fasting cycles are strong behavioral signals that entrain biological rhythms of the periphery. The feeding rhythms synchronize the activities of the metabolic organs, such as liver, synergistically with the light/dark cycle primarily entraining the suprachiasmatic nucleus. The likely phase misalignment between the feeding rhythms and the light/dark cycles appears to induce circadian disruptions leading to multiple physiological abnormalities motivating the need to investigate the mechanisms behind joint light-feeding circadian entrainment of peripheral tissues...
2017: Gene Regulation and Systems Biology
https://www.readbyqxmd.com/read/28466791/computational-modeling-of-the-cell-autonomous-mammalian-circadian-oscillator
#16
Olga A Podkolodnaya, Natalya N Tverdokhleb, Nikolay L Podkolodnyy
This review summarizes various mathematical models of cell-autonomous mammalian circadian clock. We present the basics necessary for understanding of the cell-autonomous mammalian circadian oscillator, modern experimental data essential for its reconstruction and some special problems related to the validation of mathematical circadian oscillator models. This work compares existing mathematical models of circadian oscillator and the results of the computational studies of the oscillating systems. Finally, we discuss applications of the mathematical models of mammalian circadian oscillator for solving specific problems in circadian rhythm biology...
February 24, 2017: BMC Systems Biology
https://www.readbyqxmd.com/read/28448626/genetic-background-dependent-effects-of-murine-micro-rnas-on-circadian-clock-function
#17
Silke Kiessling, Ahmet Ucar, Kamal Chowdhury, Henrik Oster, Gregor Eichele
MicroRNAs (miRs) are important regulators of a wide range of biological processes. Antagomir studies suggest an implication of miR-132 in the functionality of the mammalian circadian clock. miR-212 and miR-132 are tandemly processed from the same transcript and share the same seed region. We found the clock modulator miR-132 and miR-212 to be expressed rhythmically in the central circadian clock. Consequently, mRNAs implicated in circadian functions may likely be targeted by both miRs. To further characterize the circadian role we generated mice with stable deletion of the miR-132/212 locus and compared the circadian behavior of mutant and wild-type control animals on two genetic backgrounds frequently used in chronobiological research, C57BL/6N and 129/Sv...
2017: PloS One
https://www.readbyqxmd.com/read/28440906/familial-longevity-is-characterized-by-high-circadian-rhythmicity-of-serum-cholesterol-in-healthy-elderly-individuals
#18
Rosa van den Berg, Raymond Noordam, Sander Kooijman, Steffy W M Jansen, Abimbola A Akintola, P Eline Slagboom, Hanno Pijl, Patrick C N Rensen, Nienke R Biermasz, Diana van Heemst
The biological clock, whose function deteriorates with increasing age, determines bodily circadian (i.e. 24h) rhythms, including that of cholesterol metabolism. Dampening of circadian rhythms has been associated with aging and disease. Therefore, we hypothesized that individuals with a familial predisposition for longevity have a higher amplitude circadian serum cholesterol concentration rhythm. The aim of this study was to investigate circadian rhythmicity of serum cholesterol concentrations in offspring of nonagenarian siblings and their partners...
April 2017: Aging Cell
https://www.readbyqxmd.com/read/28439594/the-effect-of-chronotherapy-on-depressive-symptoms-evidence-based-practice
#19
Anas H Khalifeh
The global prevalence of depression is increasing, along with rates of depression-associated disability and mortality, rendering depressive disorders a major public health issue. Chronotherapy involves a variety of strategies that control exposure to environmental stimuli that influence the biological clock, such as sleep deprivation (SD) or wake therapy (WT), sleep phase advance (SPA), and light and dark therapy (LT, DT). The purpose of this Evidence-Based Practice (EBP) paper is to answer PICOT questions by a review the effectiveness of chronotherapeutics interventions on depressive symptoms with depression and the depressive episode in the course of bipolar disorder...
May 2017: Saudi Medical Journal
https://www.readbyqxmd.com/read/28432608/fpgasw-accelerating-large-scale-smith-waterman-sequence-alignment-application-with-backtracking-on-fpga-linear-systolic-array
#20
Xia Fei, Zou Dan, Lu Lina, Man Xin, Zhang Chunlei
The Smith-Waterman (SW) algorithm based on dynamic programming is a well-known classical method for high precision sequence matching and has become the gold standard to evaluate sequence alignment software. In this paper, we propose fine-grained parallelized SW algorithms using affine gap penalty and implement a parallel computing structures to accelerating the SW with backtracking on FPGA platform. We analysis the dynamic parallel computing features of anti-diagonal elements and storage expansion problem resulting from backtracking stage, and propose a series of optimization strategies to eliminate data dependency, reduce storage requirements, and overlap memory access latency...
April 21, 2017: Interdisciplinary Sciences, Computational Life Sciences
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