Discovery and Visualization of Age-Dependent Patterns in the Diurnal Transcriptome of Drosophila
Many critical life processes are regulated by input from 24-hour external light/dark cycles, such as metabolism, cellular homeostasis, and detoxification. The circadian clock, which helps coordinate the response to these diurnal light/dark cycles, remains rhythmic across lifespan; however, rhythmic transcript expression is altered during normal aging. To better understand how aging impacts diurnal expression, we present an improved Fourier-based method for detecting and visualizing rhythmicity that is based on the relative power of the 24-hour period compared to other periods (RP24). We apply RP24 to transcript-level expre...
Source: Journal of Circadian Rhythms - December 8, 2022 Category: Biology Source Type: research

Day-Night Variations in the Concentration of Neurotransmitters in the Rat Lumbar Spinal Cord
The purpose of this study was to analyze the light-dark variations in the concentrations of several neurotransmitters in the lumbar spinal cord of rats. Six groups of male Wistar  rats were exposed to a 12 h light-12 h dark cycle for 70 days. At different time points of the experimental day (8, 12, 16, 20, 24 and 4 h), one of the groups of rats was randomly selected to be sacrificed, and the spinal cords were removed. The gamma-aminobutyric acid (GABA), glutamate (GLU), dop amine, serotonin, epinephrine (E), and norepinephrine (NE) levels in each extracted spinal cord were measured with high-pressure liquid chromatograph...
Source: Journal of Circadian Rhythms - July 19, 2021 Category: Biology Source Type: research

Genes Relevant to Tissue Response to Cancer Therapy Display Diurnal Variation in mRNA Expression in Human Oral Mucosa
Conclusion: In oral mucosa, expression of some genes relevant to treatment response  displayed diurnal variation. These genes may be candidates for development of biomarkers for optimizing individual timing of cancer therapy using non-invasively collected oral mucosa. Published on 2021-06-17 11:25:07 (Source: Journal of Circadian Rhythms)
Source: Journal of Circadian Rhythms - June 17, 2021 Category: Biology Source Type: research

Changes in 24 h Rhythmicity of Spontaneous Locomotor Activity in the Triple Transgenic Mouse for Alzheimer ’s Disease (3xTg-AD) in a Jet Lag Protocol: Correlations with Retinal Sensitivity
The progression of amyloid plaques and neurofibrillary tangles in different brain areas  is associated with the effects of Alzheimer’s disease (AD). In addition to cognitive impairment, circadian alterations in locomotor activity have also been detected, but they have not been characterized in a jet lag protocol. Therefore, the present study aimed to compare 3xTg-AD and non-transge nic mice in changes of 24 h cycles of spontaneous locomotor activity in a jet lag protocol, in an environment without a running wheel, at 3 different states of neuronal damage: early, intermediate and advanced (3, 8 and 13 months, respectiv...
Source: Journal of Circadian Rhythms - May 27, 2021 Category: Biology Source Type: research

Tubulin Polymerization Promoting Protein Affects the Circadian Timing System in C57Bl/6 Mice
The circadian timing system (CTS) is a complex set of cyclic cellular mechanisms which serve to synchronize discrete cell groups across multiple organ systems to adapt the body ’s physiology to a (roughly) 24-hour clock. Many genes and hormones have been shown to be strongly associated with the CTS, some of which include the genesBmal1, Period1, Period2, Cryptochrome1, andCryptochrome2, and the hormone melatonin. Previous data suggest that microtubule dynamics play an important role in melatonin function as it relates to the CTS in vitro, though this relationship has never been explored in vivo. The purpose of this study...
Source: Journal of Circadian Rhythms - May 21, 2021 Category: Biology Source Type: research

A Functional Adenosine Deaminase Polymorphism Associates with Evening Melatonin Levels and Sleep Quality
Increased adenosine levels throughout the day promote sleepiness. A single nucleotide  polymorphism (SNP) in the adenosine deaminase ADA gene (rs73598374) has been shown to affect sleep regulation. The extent to which lower ADA enzymatic activity is associated with the homeostatic sleep factor, melatonin, is uncertain. To test this possibility, we assessed the relationship between t he ADA polymorphism and evening melatonin levels, as well as self-reported sleep behavior. Given the close relationship between mood and sleep behavior, we further tested the impact of ADA genotype on self-reported mood. We show that relative ...
Source: Journal of Circadian Rhythms - April 28, 2021 Category: Biology Source Type: research

Daily and Estral Regulation of RFRP-3 Neurons in the Female Mice
In this study, we used a combination of neuroanatomical and electrophysiological approaches to assess whether the hypothalamic neurons expressing Arg-Phe amiderelated peptide (RFRP-3), a gonadotropin inhibitory peptide, exhibit daily and estrous stage dependent variations in female mice. Furthermore, we investigated whether arginine vasopressin (AVP), a circadian peptide produced by the suprachiamatic nucleus regulates RFRP-3 neurons. The number of c-Fos –positive RFRP-3 immunoreactive neurons is significantly reduced at the day-to-night transition with no difference between diestrus and proestrus. Contrastingly, RFRP ne...
Source: Journal of Circadian Rhythms - April 15, 2021 Category: Biology Source Type: research

Regional Differences in Height, Weight, and Body Composition may Result from Photoperiodic Responses: An Ecological Analysis of Japanese Children and Adolescents
This ecological study examined whether geographical differences in the physique of Japanese children and adolescents can be explained from the perspective of photoperiodicity induced by effective day length (light duration exceeding a certain threshold of illuminance) using prefecture-level anatomical data and Mesh Climatic Data. Multiple regression analysis for height prediction demonstrated that when controlled by weight, effective day lengths of the longest and shortest months were inversely correlated with height distribution. Conversely, for weight prediction, when controlled by height, the effective day lengths of th...
Source: Journal of Circadian Rhythms - February 22, 2021 Category: Biology Source Type: research

Metastasis of Breast Cancer Promoted by Circadian Rhythm Disruption due to Light/Dark Shift and its Prevention by Dietary Quercetin in Mice
In this study, BJMC3879Luc2 mouse breast cancer cells were transplanted into BALB/c mice. Mice were maintained under lighting conditions that modeled the two-shift system and were investigated for the effect of light/dark cycle disruption on tumor growth and lymph node metastasis. Circadian dysfunction, which was confirmed by measuring circadian locomotor activities using a nano tag device in our light/dark shift model, did not affect tumor growth. However, a significant increase in the number of lymph nodes with distant metastasis was observed. Neutrophil-to-lymphocyte ratio, which is an adverse prognostic factor of breas...
Source: Journal of Circadian Rhythms - February 19, 2021 Category: Biology Source Type: research

Sleep, Circadian Rhythmicity and Response to Chronotherapy in University Students: Tips from Chronobiology Practicals
In conclusion, significant abnormalities in the sleep-wake patterns of a small gr oup of university students were observed, and the students seemed to benefit from chronotherapy. We had a positive impression of our teaching experience, and the chronobiology courses obtained excellent student feedback. Published on 2021-01-21 10:31:39 (Source: Journal of Circadian Rhythms)
Source: Journal of Circadian Rhythms - January 21, 2021 Category: Biology Source Type: research

The Peripheral Circadian Clock and Exercise: Lessons from Young and Old Mice
Critical biological processes are under control of the circadian clock. Disruption of this clock, e.g. during aging, results in increased risk for development of chronic disease. Exercise is a protective intervention that elicits changes in both age and circadian pathologies, yet its role in regulating circadian gene expression in peripheral tissues is unknown. We hypothesized that voluntary wheel running would restore disrupted circadian rhythm in aged mice. We analyzed wheel running patterns and expression of circadian regulators in male and female C57Bl/6J mice in adult (~4 months) and old (~18 months) ages. As expected...
Source: Journal of Circadian Rhythms - December 16, 2020 Category: Biology Source Type: research

Healthcare Shift Workers ’ Temporal Habits for Eating, Sleeping, and Light Exposure: A Multi-Instrument Pilot Study
Conclusion: This pilot study utilized primarily objective measurement to examine shift workers ’ habits outside the laboratory. Although no association between BMI and eating patterns/activity/sleep was observed across groups, a small, homogeneous sample may have influenced this. Overall, shift work was associated with 1) increased calorie intake and higher-fat and -carbohydrate diets and 2 ) sleep deprivation. A larger, more diverse sample can participate in future studies that objectively measure shift workers’ real-world habits. Published on 2020-10-21 10:20:23 (Source: Journal of Circadian Rhythms)
Source: Journal of Circadian Rhythms - October 21, 2020 Category: Biology Source Type: research

Using Circadian Rhythm Patterns of Continuous Core Body Temperature to Improve Fertility and Pregnancy Planning
Conclusions: Analysis of CBT via continuous recording reveals patterns in the interactions of circadian and infradian CBT rhythms capable of accurately predicting the fertility window and hormonal patterns suggesting oligo-ovulation and subfertility. New wearable technologies can facilitate employment of hormone-associated changes in CBT for pregnancy planning and offer clinical insight to infertility and menopause. Published on 2020-09-24 10:10:10 (Source: Journal of Circadian Rhythms)
Source: Journal of Circadian Rhythms - September 24, 2020 Category: Biology Source Type: research

The Influence of Shift Work on the Quality of Sleep and Executive Functions
This study aimed to investigate the influence of shift work on the Quality of Sleep (QOS) and Executive Functions (EF). Thirty shift workers and thirty day workers first completed a demographic questionnaire. They then were tested using the Pittsburgh Sleep Quality Index (PSQI) and EF tests, including the Corsi Block-Tapping Task (CBTT), Berg ’s Card Sorting Task (BCST), and the Continuous Performance Task (CPT). Results were subjected to non-parametric Chi-Square Tests, the Mann-Whitney U Test, and Independent T-Tests. Shift workers had significantly poorer sleep quality than day workers, which was shown in PSQI global ...
Source: Journal of Circadian Rhythms - June 24, 2020 Category: Biology Source Type: research

Diurnal Preference and Grey Matter Volume in a Large Population of Older Adults: Data from the UK Biobank
Eveningness (a diurnal preference for evening time) is associated with a number of negative health outcomes and risk and prevalence for psychiatric disorder. Our understanding of the anatomical substrates of diurnal preference, however, is limited. The current study used Voxel-Based Morphometry to compare grey matter volume in a large sample (N = 3730) of healthy adults determined by questionnaire to be either definite morning-type or definite evening-type. Eveningness was associated with increased grey matter volume in precuneus, brain regions implicated in risk and reward processing (bilateral nucleus accumbens, caudate,...
Source: Journal of Circadian Rhythms - May 8, 2020 Category: Biology Source Type: research