scholarly journals Physiological responses to food intake throughout the day

2014 ◽  
Vol 27 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Jonathan D. Johnston
Keyword(s):  
Circadian Rhythms ◽  
Unmet Need ◽  
Time Of Day ◽  
Research Field ◽  
Biological Data ◽  
Model Systems ◽  
Physiological Processes ◽  
Circadian Timing System ◽  
Glucose Profiles ◽  
Molecular Components

Circadian rhythms act to optimise many aspects of our biology and thereby ensure that physiological processes are occurring at the most appropriate time. The importance of this temporal control is demonstrated by the strong associations between circadian disruption, morbidity and disease pathology. There is now a wealth of evidence linking the circadian timing system to metabolic physiology and nutrition. Relationships between these processes are often reciprocal, such that the circadian system drives temporal changes in metabolic pathways and changes in metabolic/nutritional status alter core molecular components of circadian rhythms. Examples of metabolic rhythms include daily changes in glucose homeostasis, insulin sensitivity and postprandial response. Time of day alters lipid and glucose profiles following individual meals whereas, over a longer time scale, meal timing regulates adiposity and body weight; these changes may occur via the ability of timed feeding to synchronise local circadian rhythms in metabolically active tissues. Much of the work in this research field has utilised animal and cellular model systems. Although these studies are highly informative and persuasive, there is a largely unmet need to translate basic biological data to humans. The results of such translational studies may open up possibilities for using timed dietary manipulations to help restore circadian synchrony and downstream physiology. Given the large number of individuals with disrupted rhythms due to, for example, shift work, jet-lag, sleep disorders and blindness, such dietary manipulations could provide widespread improvements in health and also economic performance.

Circadian rhythms in the chemoreflex control of breathing

2000 ◽  
Vol 278 (1) ◽  
pp. R282-R286 ◽  
Author(s):  
Richard Stephenson ◽  
Ravi M. Mohan ◽  
James Duffin ◽  
Tim M. Jarsky
Keyword(s):  
Circadian Rhythm ◽  
Circadian Rhythms ◽  
Metabolic Rate ◽  
Lung Ventilation ◽  
Time Of Day ◽  
Carbon Dioxide Partial Pressure ◽  
Circadian Variations ◽  
Circadian Timing System ◽  
Respiratory Chemoreflex ◽  
End Tidal

Mechanisms underlying the circadian rhythm in lung ventilation were investigated. Ten healthy male subjects were studied for 36 h using a constant routine protocol to minimize potentially confounding variables. Laboratory light, humidity, and temperature remained constant, subjects did not sleep, and their meals and activities were held to a strict schedule. Respiratory chemoreflex responses were measured every 3 h using an iso-oxic rebreathing technique incorporating prior hyperventilation. Subjects exhibited circadian rhythms in oral temperature and respiratory chemoreflex responses, but not in metabolic rate. Basal ventilation [i.e., at subthreshold end-tidal carbon dioxide partial pressure ([Formula: see text])] did not vary with time of day, but the ventilatory response to suprathreshold[Formula: see text] exhibited a rhythm amplitude of ∼25%, mediated mainly by circadian variations in the CO2 threshold for tidal volume. We conclude that the circadian rhythm in lung ventilation is not a simple consequence of circadian variations in arousal state and metabolic rate. By raising the chemoreflex threshold, the circadian timing system may increase the propensity for respiratory instability at night.

Circadian rhythms in a nutshell

2000 ◽  
Vol 3 (2) ◽  
pp. 59-74 ◽  
Author(s):  
ISAAC EDERY
Keyword(s):  
Circadian Rhythms ◽  
Molecular Mechanisms ◽  
The Elderly ◽  
Life Forms ◽  
Circadian Clocks ◽  
Model Systems ◽  
Circadian Timing System ◽  
Environmental Transitions ◽  
Rotation Of The Earth ◽  
Living Organisms

Edery, Isaac. Circadian rhythms in a nutshell. Physiol Genomics 3: 59–74, 2000.—Living organisms on this planet have adapted to the daily rotation of the earth on its axis. By means of endogenous circadian clocks that can be synchronized to the daily and seasonal changes in external time cues, most notably light and temperature, life forms anticipate environmental transitions, perform activities at biologically advantageous times during the day, and undergo characteristic seasonal responses. The effects of transmeridian flight and shift work are stark reminders that although modern technologies can create “cities that never sleep” we cannot escape the recalcitrance of endogenous clocks that regulate much of our physiology and behavior. Moreover, malfunctions in the human circadian timing system are implicated in several disorders, including chronic sleep disorders in the elderly, manic-depression, and seasonal affective disorders (SAD or winter depression). Recent progress in understanding the molecular mechanisms underlying circadian rhythms has been remarkable. In its most basic form, circadian clocks are comprised of a set of proteins that, by virtue of the design principles involved, generate a self-sustaining transcriptional-translational feedback loop with a free-running period of about 24 h. One or more of the clock components is acutely sensitive to light, resulting in an oscillator that can be synchronized to local time. This review provides an overview of the roles circadian clocks play in nature, how they might have arisen, human health concerns related to clock dysfunction, and mainly focuses on the clockworks found in Drosophila and mice, the two best studied animal model systems for understanding the biochemical and cellular bases of circadian rhythms.

Noncoding RNAs in Medicinal Plants and Their Regulatory Roles in Bioactive Compound Production

2020 ◽  
Vol 21 ◽  
Author(s):  
Caili Li ◽  
Meizhen Wang ◽  
Xiaoxiao Qiu ◽  
Hong Zhou ◽  
Shanfa Lu
Keyword(s):  
Medicinal Plants ◽  
Current Knowledge ◽  
Salvia Miltiorrhiza ◽  
Noncoding Rnas ◽  
Bioactive Compound ◽  
Research Field ◽  
Model Systems ◽  
Small Interfering Rnas ◽  
Regulatory Pathways ◽  
Regulatory Modules

Background: Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), small interfering RNAs (siRNAs) and long noncoding RNAs (lncRNAs), play significant regulatory roles in plant development and secondary metabolism and are involved in plant response to biotic and abiotic stresses. They have been intensively studied in model systems and crops for approximately two decades and massive amount of information have been obtained. However, for medicinal plants, ncRNAs, particularly their regulatory roles in bioactive compound biosynthesis, are just emerging as a hot research field. Objective: This review aims to summarize current knowledge on herbal ncRNAs and their regulatory roles in bioactive compound production. Results and Conclusion: So far, scientists have identified thousands of miRNA candidates from over 50 medicinal plant species and 11794 lncRNAs from Salvia miltiorrhiza, Panax ginseng, and Digitalis purpurea. Among them, more than 30 miRNAs and five lncRNAs have been predicted to regulate bioactive compound production. The regulation may achieve through various regulatory modules and pathways, such as the miR397-LAC module, the miR12112-PPO module, the miR156-SPL module, the miR828-MYB module, the miR858-MYB module, and other siRNA and lncRNA regulatory pathways. Further functional analysis of herbal ncRNAs will provide useful information for quality and quantity improvement of medicinal plants.

Circadian rhythms, sleep, and anti-cancer treatments

2018 ◽  
Author(s):  
Pasquale F. Innominato ◽  
David Spiegel
Keyword(s):  
Quality Of Life ◽  
Circadian Rhythms ◽  
Biological Functions ◽  
Cancer Treatments ◽  
Anti Cancer ◽  
Timing System ◽  
Physical Wellbeing ◽  
Circadian Timing System ◽  
Chemotherapy Agents

The circadian timing system temporally regulates biological functions relevant for psycho-physical wellbeing, spanning all the systems related to health. Hence, disruption of circadian rhythms, along with sleep cycles, is associated with the development of several diseases, including cancer. Moreover, altered circadian and sleep functions negatively impact on cancer patients’ quality of life and survival, above and beyond known determinants of outcome. This alteration can occur as a consequence of cancer, but also of anti-cancer treatments. Indeed, circadian rhythms govern also the ability of detoxifying chemotherapy agents across the 24 hours. Hence, adapting chemotherapy delivery to the molecular oscillations in relevant drug pathways can decrease toxicity to healthy cells, while increasing the number of cancer cells killing. This chronomodulated chemotherapy approach, together with the maintenance of proper circadian function throughtout the whole disease challenge, would finally result in safer and more active anticancer treatments, and in patients experiencing better quality and quantity of life.

296 Sex differences in sleep and wakefulness of police officers working shifts: evidence from a field study

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A118-A118
Author(s):  
Gabriela Caetano ◽  
Laura Kervezee ◽  
Fernando Gonzales-Aste ◽  
Philippe Boudreau ◽  
Diane Boivin
Keyword(s):  
Sex Differences ◽  
Circadian Rhythms ◽  
Shift Work ◽  
Police Officers ◽  
Field Studies ◽  
Time Of Day ◽  
Cycle Phase ◽  
Shift Workers ◽  
Work Related ◽  
Time Awake

Abstract Introduction National reports of work-related injuries found the excess risk of work injury attributed to shift work to be significantly higher among women. The Working Time Society (WTS) concluded that male sex is one of the few factors that is “consistently associated with perceived or actual shift work tolerance”. However, it is unclear if physiological parameters are involved. Laboratory-controlled studies report sex differences in circadian rhythms (body temperature, melatonin). In sleep deprivation protocols, alertness and cognitive performances were affected by sex, menstrual cycle phase and hormonal contraceptives [HC] use. Nevertheless, field studies that compare male and female shift workers are scarce. Methods An observational study including 76 police officers working on patrol: 56 males and 20 females (11 using [HC], 6 not using [non-HC] and 3 with unknown use of hormonal contraception) aged 32.0 ± 5.3 years. Participants were followed throughout a month-long work cycle (1,457 morning, evening, night, or other shifts, plus rest days). They filled out time-stamped questionnaires (Samn-Perelli, KSS, Visual Analogue Scales, ~5/day; sleep and work-related information, ~1–2/day), completed 5-min Psychomotor Vigilance Tasks (PVT, ~2/day), and wore an actigraph to collect activity data. Linear mixed-effects models were used to analyze the effects of group, time awake and time-of-day on fatigue, sleepiness, alertness, mood and PVT measures. Results Self-reported measures and psychomotor performance significantly varied with time awake and time-of-day. Fatigue and sleepiness levels were significantly higher among female compared to male police officers, both with time awake and across the 24-h day. These variations were similar between non-HC females and the other groups. Compared to males, HC females were more fatigued and less alert, both with time awake and across the 24-h day, and sleepier with time awake. Having children at home did not explain these differences. Conclusion The results of this study expand our knowledge on the sex differences in the sleep and circadian physiology and demonstrate a critical effect of HC on women fatigue, sleepiness and alertness when working shifts. Sex and hormonal parameters must be considered in occupational medicine as well as in future laboratory and field studies on shift workers and circadian rhythms. Support (if any) IRSST, FRQS.

scholarly journals Exercise mitigates sleep-loss-induced changes in glucose tolerance, mitochondrial function, sarcoplasmic protein synthesis, and circadian rhythms

2020 ◽  
Author(s):  
Nicholas J Saner ◽  
Matthew J-C Lee ◽  
Jujiao Kuang ◽  
Nathan W Pitchford ◽  
Gregory D Roach ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Circadian Rhythms ◽  
Glucose Tolerance ◽  
Mitochondrial Function ◽  
Sleep Loss ◽  
Physiological Processes ◽  
Sarcoplasmic Protein ◽  
Concomitant Reduction ◽  
High Intensity Interval ◽  
Inadequate Sleep

AbstractSleep loss has emerged as a risk factor for the development of impaired glucose tolerance. The mechanisms underpinning this observation are unknown; however, both mitochondrial dysfunction and circadian misalignment have been proposed. Given that exercise improves glucose tolerance, mitochondrial function, and alters circadian rhythms, we investigated whether exercise may counteract the effects induced by inadequate sleep. We report that sleeping 4 hours per night, for five nights, reduced glucose tolerance, with novel observations of associated reductions in mitochondrial function, sarcoplasmic protein synthesis, and measures of circadian rhythmicity; however, incorporating three sessions of high-intensity interval exercise (HIIE) during this period mitigates these effects. These data demonstrate, for the first time, a sleep loss-induced concomitant reduction in a range of physiological processes linked to metabolic function. These same effects are not observed when exercise is performed during a period of inadequate sleep, supporting the use of HIIE as an intervention to mitigate the detrimental physiological effects of sleep loss.

scholarly journals Time-of-day-dependent responses of cyanobacterial cellular viability against oxidative stress

2019 ◽  
Author(s):  
Kenya Tanaka ◽  
Ginga Shimakawa ◽  
Shuji Nakanishi
Keyword(s):  
Oxidative Stress ◽  
Circadian Rhythms ◽  
Cell Viability ◽  
Circadian Clock ◽  
Stress Tolerance ◽  
Time Of Day ◽  
Circadian Oscillation ◽  
Subjective Time ◽  
Rhythmic Pattern ◽  
Oxidative Stress Tolerance

AbstractAs an adaptation to periodic fluctuations of environmental light, photosynthetic organisms have evolved a circadian clock. Control by the circadian clock of many cellular physiological functions, including antioxidant enzymes, metabolism and the cell cycle, has attracted attention in the context of oxidative stress tolerance. However, since each physiological function works in an integrated manner to deal with oxidative stress, whether or not cell responses to oxidative stress are under circadian control remains an open question. In fact, circadian rhythms of oxidative stress tolerance have not yet been experimentally demonstrated. In the present work, we applied an assay using methyl viologen (MV), which generates reactive oxygen species (ROS) under light irradiation, and experimentally verified the circadian rhythms of oxidative stress tolerance in photosynthetic cells of the cyanobacterium Synechococcus elongatus PCC7942, a standard model species for investigation of the circadian clock. Here, we report that ROS generated by MV treatment causes damage to stroma components and not to the photosynthetic electron transportation chain, leading to reduced cell viability. The degree of decrease in cell viability was dependent on the subjective time at which oxidative stress was applied. Thus, oxidative stress tolerance was shown to exhibit circadian rhythms. In addition, the rhythmic pattern of oxidative stress tolerance disappeared in mutant cells lacking the essential clock genes. Notably, ROS levels changed periodically, independent of the MV treatment. Thus, we demonstrate for the first time that in cyanobacterial cells, oxidative stress tolerance shows circadian oscillation.

scholarly journals ESPO/ BIOLOGICAL SCIENCES SECTION SYMPOSIUM: EMERGING INSIGHTS IN INTERACTIONS AND NETWORKS IN THE BIOLOGY OF AGING DEVELOPING C. ELEGANS TO STUDY AGE-RELATED EXTRACELLULAR VESICLE SIGNALS

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S424-S424
Author(s):  
Joshua Russell ◽  
Matt Kaeberlein
Keyword(s):  
Biological Sciences ◽  
Mammalian Cell Culture ◽  
Extracellular Vesicle ◽  
Model Systems ◽  
C Elegans ◽  
Physiological Processes ◽  
Age Related ◽  
Powerful Approach ◽  
Invertebrate Model ◽  
Biology Of Aging

Abstract All cells release vesicles into their extracellular environment. These extracellular vesicles (EVs) contain multiple classes of molecules, including nucleic acids, proteins, and lipids. EV-signaling has been shown to be impacted by many age-related physiological processes such as inflammation, mitochondrial stress, and autophagy as well as directly mediate critical functions in cellular senescence and aging. The isolation and analysis of EV cargos from mammalian cell culture and liquid biopsy samples has become a powerful approach for uncovering the messages that are packaged into these organelles. Caenorhabditis elegans is a premier model for dissecting the genetics of aging however, EV analysis has not been tenable in invertebrate model systems due to lack of methods for obtaining sufficient amounts of pure EVs. We developed a method for isolating pure EVs from C. elegans with yields sufficient for mass spectrometry and RNAseq. Here we present the analysis of the genetic and protein cargos of EVs collected from wild type and long-lived mutants collected at different time points across their lifespans. As the first investigation of age-related EV signals in an invertebrate model system we believe these results will provide insights into cell non-autonomous mechanisms of aging.

scholarly journals Free-running circadian breathing rhythms are eliminated by suprachiasmatic nucleus lesion

2020 ◽  
Vol 129 (1) ◽  
pp. 49-57
Author(s):  
Benton S. Purnell ◽  
Gordon F. Buchanan
Keyword(s):  
Sleep Apnea ◽  
Circadian Rhythms ◽  
Suprachiasmatic Nucleus ◽  
Time Of Day ◽  
Sudden Unexpected Death ◽  
Constant Darkness ◽  
Unexpected Death ◽  
Treatment And Prevention ◽  
Free Running

It has long been appreciated that breathing is altered by time of day. This study demonstrates that rhythmicity in breathing persists in constant darkness but is dependent on the suprachiasmatic nucleus in the hypothalamus. Understanding circadian rhythms in breathing may be important for the treatment and prevention of diseases such as sleep apnea and sudden unexpected death in epilepsy.

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