Search results for "circadian rhythm"

The Lipid-Sensor Candidates CD36 and GPR120 Are Differentially Regulated by Dietary Lipids in Mouse Taste Buds: Impact on Spontaneous Fat Preference

2011

BACKGROUND: Recent studies in rodents and humans suggest that the chemoreception of long-chain fatty acids (LCFA) in oral cavity is involved in the spontaneous preference for fatty foods and might contribute to the obesity risk. CD36 and GPR120 are LCFA receptors identified in rodent taste bud cells. The fact that CD36 or GPR120 gene inactivation leads to a decrease in the preference for lipids raises the question of the respective role(s) played by these gustatory lipid-sensor candidates. METHODOLOGY/PRINCIPAL FINDINGS: Using a combination of biochemical, nutritional and behavioural studies in wild-type, CD36(+/-)and CD36(-/-) mice, it was found that: 1°) CD36 and GPR120 display different …

Phylostratic Shift of Whole-Genome Duplications in Normal Mammalian Tissues towards Unicellularity Is Driven by Developmental Bivalent Genes and Reve…

2020

Tumours were recently revealed to undergo a phylostratic and phenotypic shift to unicellularity. As well, aggressive tumours are characterized by an increased proportion of polyploid cells. In order to investigate a possible shared causation of these two features, we performed a comparative phylostratigraphic analysis of ploidy-related genes, obtained from transcriptomic data for polyploid and diploid human and mouse tissues using pairwise cross-species transcriptome comparison and principal component analysis. Our results indicate that polyploidy shifts the evolutionary age balance of the expressed genes from the late metazoan phylostrata towards the upregulation of unicellular and early m…

An integrated approach based on uniform quantization for the evaluation of complexity of short-term heart period variability: Application to 24 h Hol…

2007

We propose an integrated approach based on uniform quantization over a small number of levels for the evaluation and characterization of complexity of a process. This approach integrates information-domain analysis based on entropy rate, local nonlinear prediction, and pattern classification based on symbolic analysis. Normalized and non-normalized indexes quantifying complexity over short data sequences (∼300 samples) are derived. This approach provides a rule for deciding the optimal length of the patterns that may be worth considering and some suggestions about possible strategies to group patterns into a smaller number of families. The approach is applied to 24 h Holter recordings of …

The interaction between circadian rhythms of endothelial function: resting versus recruitable endothelial function

2013

Time-related changes in size of nuclei of pinealocytes in rats

1981

In a study of 96 adult male Sprague-Dawley rats, da- and time-related changes of the mean nuclear volume of pinealocytes were determined with the aim of testing the reproducibility of the karyometric findings described by Quay and Renzoni (1966). It is shown (i) that statistically significant differences exist between the central and peripheral mean volumes of pinealocyte nuclei/group of animals and time point (p less than 0.001), (ii) that the day and time related differences are statistically different in both regions (p less than 0.001), (iii) that in the center and periphery of the pineal body different diurnal patterns exist, and (iv) that the diurnal patterns are not parallel in the t…

How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

2015

This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1). For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace chang…

Endogenous fluctuations of DNA topology in the chloroplast of Chlamydomonas reinhardtii.

1998

DNA supercoiling in the chloroplast of the unicellular green alga Chlamydomonas reinhardtii was found to change with a diurnal rhythm in cells growing in alternating 12-h dark-12-h light periods. Highest and lowest DNA superhelicities occurred at the beginning and towards the end of the 12-h light periods, respectively. The fluctuations in DNA supercoiling occurred concurrently and in the same direction in two separate parts of the chloroplast genome, one containing the genes psaB, rbcL, and atpA and the other containing the atpB gene. Fluctuations were not confined to transcribed DNA regions, indicating simultaneous changes in DNA conformation all over the chloroplast genome. Because the d…

Production and chronobiology of emergence of the cercariae of Euparyphium albuferensis (Trematoda: Echinostomatidae).

1999

The production and the chronobiology of emergence of the cercariae of Euparyphium albuferensis from Gyraulus chinensis experimentally infected with a single miracidium were established during 28 consecutive days from the first day of cercarial shedding. Moreover, the effect of a sudden change in light-dark cycling was investigated. Although the daily cercarial shedding rates show great variability, a progressive increase in cercarial production was observed in the first weeks of the cercarial shedding periods, probably in relation to the demography of intramollusean larval stages. Under 12:12 light-dark cycling condition;, it, albuferensis cercariae emerged in the light, and the rhythm was …

Diurnal changes in the perception of emotions in music: Does the time of day matter?

2014

According to the Hindustani music tradition, the ability of a song to induce certain emotions depends on the time of day: playing a song at the right time is said to maximise its emotional effect. The present exploratory study investigated this claim by combining findings in chronobiology, mood research and music perception. It has already been established that some aspects of our mood fluctuations follow a cyclical pattern. Besides, it is a known fact that our current mood influences our perception and assessment of emotions. However, these elements have never been linked together in a study examining the effect of mood cyclicity on perceived emotions in music. To test the hypothesis of a…

Diurnal variation of corticotropin-releasing factor binding sites in the rat brain and pituitary.

1996

1. Corticotropin-releasing factor (CRF) is thought to be involved in the regulation of the diurnal activity of the hypothalamus-pituitary-adrenal (HPA) axis and to act as a neurotransmitter in the brain. To date it is unknown whether the binding sites of the central CRF system are subject to diurnal variations. 2. We measured the number of CRF binding sites over the course of a complete 24-hr light-dark cycle in the pituitary, amygdala, bed nucleus of the stria terminalis (BNST), cingulate cortex, visceral cortex, paraventricular nucleus of the hypothalamus, hippocampus, and locus ceruleus of rats by in vitro receptor autoradiography with iodinated ovine CRF. A 24-hr time course was also es…