Less is more: Light sampling via throttled visual phototransduction robustly synchronizes the Drosophila circadian clock in the absence of Cryptochrome

SummaryThe daily changes of light and dark exemplify a prominent cue for the synchronization of internal circadian clocks to external time. The match between external and internal time is crucial for the fitness of organisms and desynchronization has been linked to numerous physical and mental health problems in humans. Organisms therefore developed complex and not fully understood mechanisms to synchronize their circadian clock to light. In mammals and in Drosophila both the visual system and dedicated non-image forming photoreceptors contribute to light resetting of the circadian clock. In the fruit fly, light-dependent degradation of the clock protein TIMELESS (TIM) by the blue light photoreceptor Cryptochrome is considered the main mechanism for clock synchronization, although the visual system also contributes. In order to understand the nature of the visual system contribution, we generated a genetic variant exhibiting extremely slow phototransduction kinetics, yet normal sensitivity. We show that in this variant the visual system is able to contribute its full share to circadian clock entrainment, both with regard to behavioral and molecular synchronization to light:dark cycles. This function depends on an alternative Phospholipase C-ß enzyme, encoded by PLC21C, presumably playing a dedicated role in clock resetting by light. We show that this pathway requires the ubiquitin ligase CULLIN-3, presumably mediating CRY-independent degradation of TIM during light:dark cycles. Our results suggest that visual system contribution to circadian clock entrainment operates on a drastically slower time scale compared with fast, visual and image forming phototransduction. Our findings are therefore consistent with the general idea that the visual system samples light over prolonged periods of time (hours) in order to reliably synchronize their internal clocks with the external time.

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Peripheral Sensory Organs Contribute to Temperature Synchronization of the Circadian Clock in Drosophila melanogaster

Frontiers in Physiology ◽

10.3389/fphys.2021.622545 ◽

2021 ◽

Vol 12 ◽

Author(s):

Rebekah George ◽

Ralf Stanewsky

Keyword(s):

Gene Expression ◽

Drosophila Melanogaster ◽

Circadian Clock ◽

Temperature Fluctuations ◽

Fruit Fly ◽

Circadian Clocks ◽

Sensory Cells ◽

Clock Gene Expression ◽

External Time ◽

Peripheral Sensory

Circadian clocks are cell-autonomous endogenous oscillators, generated and maintained by self-sustained 24-h rhythms of clock gene expression. In the fruit fly Drosophila melanogaster, these daily rhythms of gene expression regulate the activity of approximately 150 clock neurons in the fly brain, which are responsible for driving the daily rest/activity cycles of these insects. Despite their endogenous character, circadian clocks communicate with the environment in order to synchronize their self-sustained molecular oscillations and neuronal activity rhythms (internal time) with the daily changes of light and temperature dictated by the Earth’s rotation around its axis (external time). Light and temperature changes are reliable time cues (Zeitgeber) used by many organisms to synchronize their circadian clock to the external time. In Drosophila, both light and temperature fluctuations robustly synchronize the circadian clock in the absence of the other Zeitgeber. The complex mechanisms for synchronization to the daily light–dark cycles are understood with impressive detail. In contrast, our knowledge about how the daily temperature fluctuations synchronize the fly clock is rather limited. Whereas light synchronization relies on peripheral and clock-cell autonomous photoreceptors, temperature input to the clock appears to rely mainly on sensory cells located in the peripheral nervous system of the fly. Recent studies suggest that sensory structures located in body and head appendages are able to detect temperature fluctuations and to signal this information to the brain clock. This review will summarize these studies and their implications about the mechanisms underlying temperature synchronization.

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Genomic heterogeneity affects the response to Daylight Saving Time

10.1101/2021.03.10.434637 ◽

2021 ◽

Author(s):

Jonathan Tyler ◽

Yu Fang ◽

Cathy Goldstein ◽

Daniel Forger ◽

Srijan Sen ◽

...

Keyword(s):

Circadian Rhythms ◽

Shift Work ◽

Mental Health Problems ◽

Multiple Time ◽

Physical And Mental Health ◽

Daylight Saving Time ◽

Circadian Misalignment ◽

Daylight Saving ◽

The One ◽

External Time

ABSTRACTCircadian rhythms drive the timing of many physiological events in the 24-hour day. When individuals undergo an abrupt external shift (e.g., change in work schedule or travel across multiple time zones), circadian rhythms become misaligned with the new time and may take several days to adjust. Chronic circadian misalignment, e.g., as a result of shift work, has been shown to lead to several physical and mental health problems. Despite the serious health implications of circadian misalignment, relatively little is known about how genetic variation affects an individual’s ability to shift to abrupt external changes. Accordingly, we use the one-hour advance from the onset of daylight saving time (DST) as a natural experiment to comprehensively study how individual heterogeneity affects the shift of sleep-wake rhythms in response to an abrupt external time change. We find that individuals genetically predisposed to a morning tendency adjust to the advance in a few days, while genetically predisposed evening-inclined individuals have not shifted. Observing differential effects by genetic disposition after a one-hour advance underscores the importance of heterogeneity in adaptation to external schedule shifts, and these genetic differences may affect how individuals adjust to jet lag or shift work as well.

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Entrainment of the Drosophila clock by the visual system

Neuroscience Insights ◽

10.1177/2633105520903708 ◽

2020 ◽

Vol 15 ◽

pp. 263310552090370

Author(s):

Matthias Schlichting

Keyword(s):

Drosophila Melanogaster ◽

Visual System ◽

Clock Synchronization ◽

Fruit Fly ◽

Circadian Clocks ◽

Cyclic Change ◽

Animal Physiology ◽

Light Entrainment ◽

Physiological Evidence ◽

External Cues

Circadian clocks evolved as an adaptation to the cyclic change of day and night. To precisely adapt to this environment, the endogenous period has to be adjusted every day to exactly 24 hours by a process called entrainment. Organisms can use several external cues, called zeitgebers, to adapt. These include changes in temperature, humidity, or light. The latter is the most powerful signal to synchronize the clock in animals. Research shows that a complex visual system and circadian photoreceptors work together to adjust animal physiology to the outside world. This review will focus on the importance of the visual system for clock synchronization in the fruit fly Drosophila melanogaster. It will cover behavioral and physiological evidence that supports the importance of the visual system in light entrainment.

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Genomic heterogeneity affects the response to Daylight Saving Time

Scientific Reports ◽

10.1038/s41598-021-94459-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jonathan Tyler ◽

Yu Fang ◽

Cathy Goldstein ◽

Daniel Forger ◽

Srijan Sen ◽

...

Keyword(s):

Shift Work ◽

Mental Health Problems ◽

Circadian Clocks ◽

Multiple Time ◽

Physical And Mental Health ◽

Daylight Saving Time ◽

Circadian Misalignment ◽

Daylight Saving ◽

The One ◽

External Time

AbstractCircadian clocks control the timing of many physiological events in the 24-h day. When individuals undergo an abrupt external shift (e.g., change in work schedule or travel across multiple time zones), circadian clocks become misaligned with the new time and may take several days to adjust. Chronic circadian misalignment, e.g., as a result of shift work, has been shown to lead to several physical and mental health problems. Despite the serious health implications of circadian misalignment, relatively little is known about how genetic variation affects an individual’s ability to entrain to abrupt external changes. Accordingly, we used the one-hour advance from the onset of daylight saving time (DST) as a natural experiment to comprehensively study how individual heterogeneity affects the shift of sleep/wake cycles in response to an abrupt external time change. We found that individuals genetically predisposed to a morning tendency adjusted to the advance in a few days, while genetically predisposed evening-inclined individuals had not shifted. Observing differential effects by genetic disposition after a one-hour advance underscores the importance of heterogeneity in adaptation to external schedule shifts. These genetic differences may affect how individuals adjust to jet lag or shift work as well.

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Socio Demographic and Clinical Profile of Indoor Female Patients of RINPAS

Indian Journal of Psychiatric Social Work ◽

10.29120/ijpsw.2017.v8.i1.13 ◽

2017 ◽

Vol 8 (1) ◽

pp. 33

Author(s):

Rajni Suri ◽

Anshu Suri ◽

Neelam Kumari ◽

Amool R. Singh ◽

Manisha Kiran

Keyword(s):

Mental Health ◽

Mental Illness ◽

Mentally Ill ◽

Mental Health Problems ◽

Demographic Data ◽

Relevant Information ◽

Health Problems ◽

High Rate ◽

Physical And Mental Health ◽

Cross Sectional

The role of women is very crucial in our society. She cares for her parents, partner, children and other relatives. She performs all types of duties in family and also in the society without any expectations. Because of playing many roles, women often face many challenges in their life including both physical and mental. Mental health problems affect women and men equally, but some problems are more common among women including both physical and mental health problems. Aim of the study - The present study is aimed to describe and compare the clinical and socio-demographic correlates of female mentally ill patients.Â Methods and Materials: The study includes 180 female mentally ill patients based on cross sectional design and the sample for the study was drawn purposively. A semi structured socio-demographic data sheet was prepared to collect relevant information as per the need of the study. Result: The present study reveals that the socio-demographic factors contribute a vital role in mental illness. Findings also showed that majority of patients had mental problems in the age range of 20-30 have high rate. Illiterate and primary level of education and daily wage working women as well as low and middle socio-economic status women are more prone to have mental illness. Other factors like marital status, type of family and religion etc also important factors for mental illness. Keywords: Socio demographic profile, female, psychiatric patient

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Loneliness, social isolation and cardiovascular risk

British Journal of Cardiac Nursing ◽

10.12968/bjca.2019.0093 ◽

2019 ◽

Vol 14 (10) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Jackson Alun ◽

Barbara Murphy

Keyword(s):

Mental Health ◽

Risk Factors ◽

Social Isolation ◽

Mental Health Problems ◽

Cognitive Disorders ◽

Premature Death ◽

Physical And Mental Health ◽

Cardiac Events ◽

Patients At Risk ◽

Traditional Risk Factors

Loneliness and social isolation are increasingly being acknowledged as risk factors for both physical and mental health problems. Recent statistics demonstrate that loneliness and isolation are on the rise internationally, to the point of being classed as an epidemic. In this paper, the authors outline some of the recent research linking loneliness and isolation to significant chronic diseases such as cardiovascular disease and type II diabetes; mental health disorders such as anxiety and depression; cognitive disorders and dementia. Isolation has also been shown to compromise recovery after acute cardiac events, being associated with increased hospital readmission and premature death. Indeed, isolation has now been identified as a risk factor equivalent in effect to traditional risk factors such as smoking, hypertension and obesity. While distinguishing between objective and subjective indicators of isolation, the authors highlight the complexity of this phenomenon, both in terms of definition and measurement, as well as the interplay between subjective and objective indicators. Important clinical implications for health professionals working with cardiac patients are also proposed, in terms of screening for isolation, and possible interventions to support patients at risk of isolation. The aim of the current article is to emphasise the importance of acknowledging loneliness and isolation as key risk factors requiring urgent attention, both in research and in clinical practice.

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A54 THE CIRCADIAN CLOCK INFLUENCES JAK/STAT SIGNALING AND GUT PERMEABILITY

Journal of the Canadian Association of Gastroenterology ◽

10.1093/jcag/gwab002.052 ◽

2021 ◽

Vol 4 (Supplement_1) ◽

pp. 11-12

Author(s):

K Parasram ◽

D Bachetti ◽

P Karpowicz

Keyword(s):

Circadian Clock ◽

Clock Cycle ◽

Intestinal Barrier ◽

Fruit Fly ◽

Cell Types ◽

Time Of Day ◽

Acute Injury ◽

Intestinal Barrier Function ◽

Intestinal Immunity ◽

Stat Signaling

Abstract Background The circadian clock is a 24-hour feedback loop that drives rhythms in behaviours and physiological processes. This molecular timekeeper consists of the transcription factors, Clock-Cycle, that drive expression of thousands of clock-controlled genes, with two of these, Period and Timeless, acting as negative regulators of Clock-Cycle. This fundamental mechanism was initially characterized in the fruit fly, Drosophila melanogaster (Nobel Prize in Physiology & Medicine, 2017), and is highly conserved in humans. The intestine, or midgut, of Drosophila, is also similar to the human small intestine consisting of similar cellular lineage, signaling pathways, and physiological functions. The lineage of the Drosophila intestine contains the same four cell types as humans: intestinal stem cells (ISCs), progenitors called enteroblasts, enterocytes and enteroendocrine cells. This simplified lineage as well as the genetic tools available, make Drosophila an ideal model for intestinal regeneration in health and disease. We have previously shown that the circadian clock is active in ISCs, EBs and ECs during both homeostatic and regenerating conditions. Furthermore, the circadian clock regulates the mitosis of ISCs under regenerating conditions. Aims We sought to uncover if Jak/STAT signaling, one of the key pathways involved in ISC proliferation in the Drosophila intestine, shows a circadian rhythm and if there is a time-of-day difference in the regenerative response. Methods To test whether the clock regulates Jak/STAT during acute injury, we developed an irradiation assay that does not affect survival but acutely disrupts intestinal barrier function. Results Using a dynamic reporter of Jak/STAT activity we show that Period circadian clock mutants have low Jak/STAT signaling and a leaky gut phenotype. Wildtype controls show time-dependent gut leakiness upon irradiation, which is higher and time-independent in Period mutants. The level of Jak/STAT response differs depending on the time of irradiation in the controls, but is higher at all times in the mutants. Conclusions The Jak/Stat pathway regulates intestinal immunity and epithelial cell proliferation in humans, thus playing a role in colorectal cancer and inflammatory bowel disease. Our results suggest Jak/Stat is controlled by the circadian clock, which has implications for intestinal recovery following medical treatments, including radiation therapy. Funding Agencies NRC

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Using Linked Data to Examine the Epidemiology of All-Cause and Cause-Specific Mortality Following Release from Incarceration in Eleven Countries

International Journal for Population Data Science ◽

10.23889/ijpds.v5i5.1478 ◽

2020 ◽

Vol 5 (5) ◽

Author(s):

Rohan Borschmann ◽

Claire Keen ◽

Jesse T Young ◽

Alexander D Love ◽

Matthew Spittal ◽

...

Keyword(s):

Linked Data ◽

Mental Health Problems ◽

Meta Analysis ◽

Physical And Mental Health ◽

Relevant Evidence ◽

Analysis Methodology ◽

Increased Risk ◽

Global Epidemiology ◽

Individual Participant ◽

Causes And Risk Factors

IntroductionMore than 30 million adults are released from incarceration globally each year. Many experience complex physical and mental health problems, and are at markedly increased risk of preventable mortality. Despite this, evidence regarding the global epidemiology of mortality following release from incarceration is insufficient to inform the development of targeted, evidence-based responses. Many previous studies have suffered from inadequate power and poor precision, and even large studies have limited capacity to disaggregate data by specific causes of death, sub-populations or time since release to answer questions of clinical and public health relevance. Objectives and ApproachWe aimed to comprehensively document the incidence, timing, causes and risk factors for mortality in adults released from incarceration. We created the Mortality After Release from Incarceration Consortium (MARIC), a multi-disciplinary collaboration representing 29 cohorts of adults who have experienced incarceration from 11 countries. Findings across cohorts will be analysed using a two-step, individual participant data meta-analysis methodology. ResultsUsing linked data from the 29 individual cohorts, the combined sample includes 1,337,993 individuals (89% male), with 75,795 deaths recorded over 9,191,393 person-years of follow-up. Preliminary analyses indicate a marked elevation in mortality risk following release from incarceration, with this risk beginning on the day of release. At the time of writing, more detailed analyses are underway regarding all-cause and cause-specific deaths – along with risk and protective factors – and findings will be presented at the IPDLN conference in October. Conclusion / ImplicationsThe MARIC consortium represents an important advancement in the field, bringing international attention to this problem. It will provide internationally relevant evidence to guide policymakers and clinicians in reducing preventable deaths in this marginalised population.

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Characteristics of professional adaptation of correctional school teachers

Pediatrician (St Petersburg) ◽

10.17816/ped112101-108 ◽

2020 ◽

Vol 11 (2) ◽

pp. 101-108

Author(s):

Nataliia V. Kosina ◽

Anna V. Radkevich

Keyword(s):

Mental Health Problems ◽

Organizational Factors ◽

Psychological Adaptation ◽

Adaptive Strategy ◽

Professional Activity ◽

Physical And Mental Health ◽

School Teachers ◽

Factors Affecting ◽

Psychological Techniques ◽

High Level

Training and education of children with physical and mental health problems makes a number of requirements for teachers working in various correctional medical institutions. These specialists must have a high level of adaptive characteristics allowing combining up-to-date pedagogical methodology with individual approach, taking into account the current state of the child. As a result of applying complex experimental psychological techniques we managed to identify specific features of correctional teachers adaptive characteristics (when comparing with public school teachers), namely: low level of activity and optimism, insufficient adaptive strategy to cope with stress characterizing maladaptive personality types. There were also a lot of negative organizational factors affecting the process and result of professional activity: a lot of work, unauthorized persons at the lessons, interaction problems with parents, insufficiency of pupils independent work, need for individual explanation, lack of real results in teachers activity. Teachers working in correctional schools and having an average level of social and psychological adaptation give a lower evaluation of various aspects in professional activity. They have a pronounced value of psychological and physiological professional maladjustment shown in somatic, emotional and social spheres as well as motivation decrease in their professional activity. Correctional school teachers have a high degree of professional burnout and their emotional exhaustion and depersonalization are more pronounced.

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