Search results for "CLOCK"

Differential Impact of Ad Libitum or Intermittent High-Fat Diets on Bingeing Ethanol-Mediated Behaviors

2019

Background: Dietary factors have significant effects on the brain, modulating mood, anxiety, motivation and cognition. To date, no attention has been paid to the consequences that the combination of ethanol (EtOH) and a high-fat diet (HFD) have on learning and mood disorders during adolescence. The aim of the present work was to evaluate the biochemical and behavioral consequences of ethanol binge drinking and an HFD consumption in adolescent mice. Methods: Animals received either a standard diet or an HFD (ad libitum vs. binge pattern) in combination with ethanol binge drinking and were evaluated in anxiety and memory. The metabolic profile and gene expression of leptin receptors and clock…

The substitution rate of HIV-1 subtypes: a genomic approach

2017

Abstract HIV-1M causes most infections in the AIDS pandemic. Its genetic diversity is defined by nine pure subtypes and more than sixty recombinant forms. We have performed a comparative analysis of the evolutionary rate of five pure subtypes (A1, B, C, D, and G) and two circulating recombinant forms (CRF01_AE and CRF02 AG) using data obtained from nearly complete genome coding sequences. Times to the most recent common ancestor (tMRCA) and substitution rates of these HIV genomes, and their genomic partitions, were estimated by Bayesian coalescent analyses. Genomic substitution rate estimates were compared between the HIV-1 datasets analyzed by means of randomization tests. Significant diff…

Circadian clock of Drosophila montana is adapted to high variation in summer day lengths and temperatures prevailing at high latitudes

2016

Photoperiodic regulation of the circadian rhythms in insect locomotor activity has been studied in several species, but seasonal entrainment of these rhythms is still poorly understood. We have traced the entrainment of activity rhythm of northern Drosophila montana flies in a climate chamber mimicking the photoperiods and day and night temperatures that the flies encounter in northern Finland during the summer. The experiment was started by transferring freshly emerged females into the chamber in early and late summer conditions to obtain both non-diapausing and diapausing females for the studies. The locomotor activity of the females and daily changes in the expression levels of two core …

Rev-Erb modulates retinal visual processing and behavioral responses to light

2016

International audience; The circadian clock is thought to adjust retinal sensitivity to ambient light levels, yet the involvement of specific clock genes is poorly understood. We explored the potential role of the nuclear receptor subfamily 1, group D, member 1 (REV-ERB; or NR1D1) in this respect. In light-evoked behavioral tests, compared with wild-type littermates, Rev-Erb(-/-) mice showed enhanced negative masking at low light levels (0.1 lx). Rev-Erb(-/-) mouse retinas displayed significantly higher numbers of intrinsically photosensitive retinal ganglion cells (ipRGCs; 62% more compared with wild-type) and more intense melanopsin immunostaining of individual ipRGCs. In agreement with a…

Evolutionary distances corrected for purifying selection and ancestral polymorphisms.

2019

Abstract Evolutionary distance formulas that take into account effects due to ancestral polymorphisms and purifying selection are obtained on the basis of the full solution of Jukes–Cantor and Kimura DNA substitution models. In the case of purifying selection two different methods are developed. It is shown that avoiding the dimensional reduction implicitly carried out in the conventional model solving is instrumental to incorporate the quoted effects into the formalism. The problem of estimating the numerical values of the model parameters, as well as those of the correction terms, is not addressed.

Circadian Rhythm Variations and Nutrition in Children

2018

AbstractCircadian rhythms are the changes in biological processes that occur on a daily basis. Among these processes are reactions involved in metabolic homeostasis. Circadian rhythms are structured by the central clock in the suprachiasmatic nucleus of the hypothalamus via the control of melatonin expression. Circadian rhythms are also controlled by the peripheral clocks, which are intracellular mechanisms composed of the clock genes, whose expression follows a circadian pattern. Circadian rhythms are impacted by signals from the environment called zeitgebers, or time givers, which include light exposure, feeding schedule and composition, sleeping schedule and pattern, temperature, and phy…

The influence of meal frequency and timing on health in humans: The role of fasting

2019

The influence of meal frequency and timing on health and disease has been a topic of interest for many years. While epidemiological evidence indicates an association between higher meal frequencies and lower disease risk, experimental trials have shown conflicting results. Furthermore, recent prospective research has demonstrated a significant increase in disease risk with a high meal frequency (≥6 meals/day) as compared to a low meal frequency (1–2 meals/day). Apart from meal frequency and timing we also have to consider breakfast consumption and the distribution of daily energy intake, caloric restriction, and night-time eating. A central role in this complex scenario is playe…

Characterisation, analysis of expression and localisation of circadian clock genes from the perspective of photoperiodism in the aphid Acyrthosiphon …

2017

Aphids are typical photoperiodic insects that switch from viviparous parthenogenetic reproduction typical of long day seasons to oviparous sexual reproduction triggered by the shortening of photoperiod in autumn yielding an overwintering egg in which an embryonic diapause takes place. While the involvement of the circadian clock genes in photoperiodism in mammals is well established, there is still some controversy on their participation in insects. The availability of the genome of the pea aphid Acyrthosiphon pisum places this species as an excellent model to investigate the involvement of the circadian system in the aphid seasonal response. In the present report, we have advanced in the c…

2018

Abstract To function properly, organisms must adjust their physiology, behavior and metabolism in response to a suite of varying environmental conditions. One of the central regulators of these changes is organisms’ internal circadian clock, and recent evidence has suggested that the clock genes are also important in the regulation of seasonal adjustments. In particular, thermosensitive splicing of the core clock gene timeless in a cosmopolitan fly, Drosophila melanogaster, has implicated this gene to be involved in thermal adaptation. To further investigate this link we examined the splicing of timeless in a northern malt fly species, Drosophila montana, which can withstand much colder cli…

Structural and mechanistic insights into the interaction of the circadian transcription factor BMAL1 with the KIX domain of the CREB-binding protein

2019

JBC papers in press xx, 16604-16619 (2019). doi:10.1074/jbc.RA119.009845