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Circadian biology

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https://www.readbyqxmd.com/read/28229973/female-conspecifics-restore-rhythmic-singing-behaviour-in-arrhythmic-male-zebra-finches
#1
Neelu Anand Jha, Vinod Kumar
The present study investigated whether pairing with a conspecific female would restore rhythmicity in the singing behaviour of arrhythmic male songbirds. We recorded the singing and, as the circadian response indicator, monitored the activity-rest pattern in male zebra finches (Taeniopygia guttata) housed without or with a conspecific female under 12 h light: 12 h darkness (12L:12D) or constant bright light (LL bright). Both unpaired and paired birds exhibited a significant daily rhythm in the singing and activity behaviour, but paired birds, under 12L:12D, showed a ~2 h extension in the evening...
March 2017: Journal of Biosciences
https://www.readbyqxmd.com/read/28229310/diagnosis-and-treatment-of-non-24-h-sleep-wake-disorder-in-the-blind
#2
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/28228570/urinary-p75-ecd-a-prognostic-disease-progression-and-pharmacodynamic-biomarker-in-als
#3
Stephanie R Shepheard, Joanne Wuu, Michell Cardoso, Luke Wiklendt, Phil G Dinning, Tim Chataway, David Schultz, Michael Benatar, Mary-Louise Rogers
OBJECTIVE: To evaluate urinary neurotrophin receptor p75 extracellular domain (p75(ECD)) levels as disease progression and prognostic biomarkers in amyotrophic lateral sclerosis (ALS). METHODS: The population in this study comprised 45 healthy controls and 54 people with ALS, 31 of whom were sampled longitudinally. Urinary p75(ECD) was measured using an enzyme-linked immunoassay and validation included intra-assay and inter-assay coefficients of variation, effect of circadian rhythm, and stability over time at room temperature, 4°C, and repeated freeze-thaw cycles...
February 22, 2017: Neurology
https://www.readbyqxmd.com/read/28223912/diet-induced-obesity-and-circadian-disruption-of-feeding-behavior
#4
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
#5
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
#6
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
#7
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...
February 20, 2017: Nature Reviews. Microbiology
https://www.readbyqxmd.com/read/28211649/insufficient-sleep-in-adolescents-causes-and-consequences
#8
Judith A Owens, Miriam R Weiss
Insufficient sleep poses an important and complicated set of health risks in the adolescent population. Not only is deficient sleep (defined as both sleep duration inadequate to meet sleep needs and sleep timing misaligned with the body's circadian rhythms) at epidemic levels in this population, but the contributing factors are both complex and numerous and there are a myriad of negative physical and mental health, safety and performance consequences. Causes of inadequate sleep identified in this population include internal biological processes such as the normal shift (delay) in circadian rhythm that occurs in association with puberty and a developmentally-based slowing of the "sleep drive", and external factors including extracurricular activities, excessive homework load, evening use of electronic media, caffeine intake and early school start times...
February 17, 2017: Minerva Pediatrica
https://www.readbyqxmd.com/read/28203366/sex-differences-in-variability-across-timescales-in-balb-c-mice
#9
Benjamin L Smarr, Azure D Grant, Irving Zucker, Brian J Prendergast, Lance J Kriegsfeld
BACKGROUND: Females are markedly underinvestigated in the biological and behavioral sciences due to the presumption that cyclic hormonal changes across the ovulatory cycle introduce excess variability to measures of interest in comparison to males. However, recent analyses indicate that male and female mice and rats exhibit comparable variability across numerous physiological and behavioral measures, even when the stage of the estrous cycle is not considered. Hormonal changes across the ovulatory cycle likely contribute cyclic, intra-individual variability in females, but the source(s) of male variability has, to our knowledge, not been investigated...
2017: Biology of Sex Differences
https://www.readbyqxmd.com/read/28203105/association-of-fatigue-and-depression-with-circulating-levels-of-proinflammatory-cytokines-and-epidermal-growth-factor-receptor-ligands-a-correlative-study-of-a-placebo-controlled-fatigue-trial
#10
Tyvin Rich, Fengmin Zhao, Ricardo A Cruciani, David Cella, Judith Manola, Michael J Fisch
CONTEXT: The biology of fatigue and depression in cancer patients is poorly understood. Hypotheses regarding cytokines and growth factors related to sickness behavior and disruption of circadian signaling have been proposed. OBJECTIVES: We prospectively examined proinflammatory cytokines (e.g., sickness behavior model) and epidermal growth factor receptor (EGFR) ligands (e.g., circadian disruption model) in the serum of cancer patients enrolled in a clinical trial testing levocarnitine for fatigue...
2017: Cancer Management and Research
https://www.readbyqxmd.com/read/28196398/factors-of-influence-and-social-correlates-of-parturition-in-captive-campbell-s-monkeys-case-study-and-breeding-data
#11
Alban Lemasson, Ronan Jubin, Philippe Bec, Martine Hausberger
How nonhuman primates deal with birth, at the moment of delivery, and during the following days, remains poorly explored because of the unpredictability of this event, particularly for forest-dwelling arboreal species. Available studies highlight intra- and interspecific variation which suggest flexibility of the timing of delivery, of behavior associated with labor contractions and parturition, and the social context and ambient noise surrounding delivery. Here, we present the findings of a two-decade survey of reproduction in a population of captive Campbell's monkeys...
February 14, 2017: American Journal of Primatology
https://www.readbyqxmd.com/read/28186138/the-spectral-and-spatial-distribution-of-light-pollution-in-the-waters-of-the-northern-gulf-of-aqaba-eilat
#12
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/28165421/circadian-rhythms-and-hormonal-homeostasis-pathophysiological-implications
#13
REVIEW
Davide Gnocchi, Giovannella Bruscalupi
Over recent years, a deeper comprehension of the molecular mechanisms that control biological clocks and circadian rhythms has been achieved. In fact, many studies have contributed to unravelling the importance of the molecular clock for the regulation of our physiology, including hormonal and metabolic homeostasis. Here we will review the structure, organisation and molecular machinery that make our circadian clock work, and its relevance for the proper functioning of physiological processes. We will also describe the interconnections between circadian rhythms and endocrine homeostasis, as well as the underlying consequences that circadian dysregulations might have in the development of several pathologic affections...
February 4, 2017: Biology
https://www.readbyqxmd.com/read/28164449/role-of-sleep-and-circadian-disruption-on-energy-expenditure-and-in-metabolic-predisposition-to-human-obesity-and-metabolic-disease
#14
REVIEW
A W McHill, K P Wright
Weight gain, obesity and diabetes have reached alarming levels in the developed world. Traditional risk factors such as over-eating, poor nutritional choices and lack of exercise cannot fully account for the high prevalence of metabolic disease. This review paper examines the scientific evidence on two novel risk factors that contribute to dys-regulated metabolic physiology: sleep disruption and circadian misalignment. Specifically, fundamental relationships between energy metabolism and sleep and circadian rhythms and the impact of sleep and circadian disruption on metabolic physiology are examined...
February 2017: Obesity Reviews: An Official Journal of the International Association for the Study of Obesity
https://www.readbyqxmd.com/read/28162893/circadian-entrainment-to-the-natural-light-dark-cycle-across-seasons-and-the-weekend
#15
Ellen R Stothard, Andrew W McHill, Christopher M Depner, Brian R Birks, Thomas M Moehlman, Hannah K Ritchie, Jacob R Guzzetti, Evan D Chinoy, Monique K LeBourgeois, John Axelsson, Kenneth P Wright
Reduced exposure to daytime sunlight and increased exposure to electrical lighting at night leads to late circadian and sleep timing [1-3]. We have previously shown that exposure to a natural summer 14 hr 40 min:9 hr 20 min light-dark cycle entrains the human circadian clock to solar time, such that the internal biological night begins near sunset and ends near sunrise [1]. Here we show that the beginning of the biological night and sleep occur earlier after a week's exposure to a natural winter 9 hr 20 min:14 hr 40 min light-dark cycle as compared to the modern electrical lighting environment...
February 20, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28158242/de-novo-characterization-of-micrornas-in-oriental-fruit-moth-grapholita-molesta-and-selection-of-reference-genes-for-normalization-of-microrna-expression
#16
Xiu Wang, Yisong Li, Jing Zhang, Qingwen Zhang, Xiaoxia Liu, Zhen Li
MicroRNAs (miRNAs) are a group of endogenous non-coding small RNAs that have critical regulatory functions in almost all known biological processes at the post-transcriptional level in a variety of organisms. The oriental fruit moth Grapholita molesta is one of the most serious pests in orchards worldwide and threatens the production of Rosacea fruits. In this study, a de novo small RNA library constructed from mixed stages of G. molesta was sequenced through Illumina sequencing platform and a total of 536 mature miRNAs consisting of 291 conserved and 245 novel miRNAs were identified...
2017: PloS One
https://www.readbyqxmd.com/read/28156168/evolution-of-circadian-rhythms-in-drosophila-melanogaster-populations-reared-in-constant-light-and-dark-regimes-for-over-330-generations
#17
Radhika Shindey, Vishwanath Varma, K L Nikhil, Vijay Kumar Sharma
Organisms are believed to have evolved circadian clocks as adaptations to deal with cyclic environmental changes, and therefore it has been hypothesized that evolution in constant environments would lead to regression of such clocks. However, previous studies have yielded mixed results, and evolution of circadian clocks under constant conditions has remained an unsettled topic of debate in circadian biology. In continuation of our previous studies, which reported persistence of circadian rhythms in Drosophila melanogaster populations evolving under constant light, here we intended to examine whether circadian clocks and the associated properties evolve differently under constant light and constant darkness...
February 3, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28155201/dad-s-snoring-may-have-left-molecular-scars-in-your-dna-the-emerging-role-of-epigenetics-in-sleep-disorders
#18
REVIEW
Daniela Morales-Lara, Clelia De-la-Peña, Eric Murillo-Rodríguez
The sleep-wake cycle is a biological phenomena under the orchestration of neurophysiological, neurochemical, neuroanatomical, and genetical mechanisms. Moreover, homeostatic and circadian processes participate in the regulation of sleep across the light-dark period. Further complexity of the understanding of the genesis of sleep engages disturbances which have been characterized and classified in a variety of sleep-wake cycle disorders. The most prominent sleep alterations include insomnia as well as excessive daytime sleepiness...
February 2, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28154744/environmental-factors-influencing-biological-rhythms-in-newborns-from-neonatal-intensive-care-units-to-home
#19
Clarissa Bueno, Luiz Menna-Barreto
Photic and non-photic environmental factors are suggested to modulate the development of circadian rhythms in infants. Our aim is to evaluate the development of biological rhythms (circadian or ultradian) in newborns in transition from Neonatal Intensive Care Units (NICU) to home and along the first 6 months of life, to identify masking and entraining environment factors along development. Ten newborns were evaluated in their last week inside the NICU and in the first week after being delivered home; 6 babies were also followed until 6 months of corrected age...
October 2016: Sleep Science
https://www.readbyqxmd.com/read/28152213/melatonin-signaling-in-t-cells-functions-and-applications
#20
REVIEW
Wenkai Ren, Gang Liu, Shuai Chen, Jie Yin, Jing Wang, Bie Tan, Guoyao Wu, Fuller W Bazer, Yuanyi Peng, Tiejun Li, Russel J Reiter, Yulong Yin
Melatonin affects a variety of physiological processes including circadian rhythms, cellular redox status and immune function. Importantly, melatonin significantly influences T cell-mediated immune responses, which are crucial to protect mammals against cancers and infections, but are associated with pathogenesis of many autoimmune diseases. This review focuses on our current understanding of the significance of melatonin in T cell biology and the beneficial effects of melatonin in T cell response-based diseases...
February 2, 2017: Journal of Pineal Research
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