Telling the Seasons Underground: The Circadian Clock and Ambient Temperature Shape Light Exposure and Photoperiodism in a Subterranean Rodent

Living organisms anticipate the seasons by tracking the proportion of light and darkness hours within a day—photoperiod. The limits of photoperiod measurement can be investigated in the subterranean rodents tuco-tucos (Ctenomys aff. knighti), which inhabit dark underground tunnels. Their exposure to light is sporadic and, remarkably, results from their own behavior of surface emergence. Thus, we investigated the endogenous and exogenous regulation of this behavior and its consequences to photoperiod measurement. In the field, animals carrying biologgers displayed seasonal patterns of daily surface emergence, exogenously modulated by temperature. In the laboratory, experiments with constant lighting conditions revealed the endogenous regulation of seasonal activity by the circadian clock, which has a multi-oscillatory structure. Finally, mathematical modeling corroborated that tuco-tuco’s light exposure across the seasons is sufficient for photoperiod encoding. Together, our results elucidate the interrelationship between the circadian clock and temperature in shaping seasonal light exposure patterns that convey photoperiod information in an extreme photic environment.

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Daily Light Exposure Patterns Reveal Phase and Period of the Human Circadian Clock

Journal of Biological Rhythms ◽

10.1177/0748730417696787 ◽

2017 ◽

Vol 32 (3) ◽

pp. 274-286 ◽

Cited By ~ 31

Author(s):

Tom Woelders ◽

Domien G. M. Beersma ◽

Marijke C. M. Gordijn ◽

Roelof A. Hut ◽

Emma J. Wams

Keyword(s):

Circadian Clock ◽

Light Exposure ◽

Exposure Patterns

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Influence of the perceived size of a light source on non-visual effects in humans

Advanced Optical Technologies ◽

10.1515/aot-2020-0041 ◽

2020 ◽

Vol 9 (6) ◽

pp. 385-393

Author(s):

Arvid Niemeyer ◽

Lucia Rottmair ◽

Cornelius Neumann ◽

Cornelius Möckel

Keyword(s):

Working Memory ◽

Light Exposure ◽

Error Rates ◽

Positive Contribution ◽

Measurement Point ◽

Visual Effects ◽

Lighting Conditions ◽

Light Measurement ◽

And Performance ◽

Main Effects

AbstractLight not only enables humans to perceive their surroundings, but also influences their sleep–wake cycle, mood, concentration and performance. Targeted use of these so called nonvisual effects could also have a positive contribution in automobiles by keeping passengers alert, minimizing error rates or bootsting attention in general. Since construction space in vehicle interios is scarce, this study compared the influence of differently-sized light panels and thus solid angles on nonvisual effects. In a counterbalanced order, 32 volunteers were exposed to three lighting conditions in the morning: baseline (12 lx, 2200 K), small (200 lx, 6500 K, 0.05 sr) and large (200 lx, 6500 K, 0.44 sr). During each session of 60 min, alertness, concentration and working memory were assessed before and during light exposure. After data analysis no significant main effects of light, measurement point or interaction between light and measurement point could be seen.

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Light, Alertness, and Alerting Effects of White Light: A Literature Overview

Journal of Biological Rhythms ◽

10.1177/0748730418796443 ◽

2018 ◽

Vol 33 (6) ◽

pp. 589-601 ◽

Cited By ~ 23

Author(s):

Renske Lok ◽

Karin C. H. J. Smolders ◽

Domien G. M. Beersma ◽

Yvonne A. W. de Kort

Keyword(s):

White Light ◽

Light Exposure ◽

Neural Mechanisms ◽

Dependent Manner ◽

Experimental Paradigm ◽

Research Paradigms ◽

Lighting Conditions ◽

Literature Overview ◽

Dose Dependent ◽

As Effects

Light is known to elicit non–image-forming responses, such as effects on alertness. This has been reported especially during light exposure at night. Nighttime results might not be translatable to the day. This article aims to provide an overview of (1) neural mechanisms regulating alertness, (2) ways of measuring and quantifying alertness, and (3) the current literature specifically regarding effects of different intensities of white light on various measures and correlates of alertness during the daytime. In general, the present literature provides inconclusive results on alerting effects of the intensity of white light during daytime, particularly for objective measures and correlates of alertness. However, the various research paradigms employed in earlier studies differed substantially, and most studies tested only a limited set of lighting conditions. Therefore, the alerting potential of exposure to more intense white light should be investigated in a systematic, dose-dependent manner with multiple correlates of alertness and within one experimental paradigm over the course of day.

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Survival is reduced when endogenous period deviates from 24 h in a non-human primate, supporting the circadian resonance theory

Scientific Reports ◽

10.1038/s41598-020-75068-8 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Clara Hozer ◽

Martine Perret ◽

Samuel Pavard ◽

Fabien Pifferi

Keyword(s):

Circadian Rhythms ◽

Circadian Clock ◽

Microcebus Murinus ◽

Circadian Period ◽

Biological Functions ◽

Resonance Theory ◽

Aging Research ◽

Mouse Lemurs ◽

Living Organisms ◽

Human Primate

Abstract Circadian rhythms are ubiquitous attributes across living organisms and allow the coordination of internal biological functions with optimal phases of the environment, suggesting a significant adaptive advantage. The endogenous period called tau lies close to 24 h and is thought to be implicated in individuals’ fitness: according to the circadian resonance theory, fitness is reduced when tau gets far from 24 h. In this study, we measured the endogenous period of 142 mouse lemurs (Microcebus murinus), and analyzed how it is related to their survival. We found different effects according to sex and season. No impact of tau on mortality was found in females. However, in males, the deviation of tau from 24 h substantially correlates with an increase in mortality, particularly during the inactive season (winter). These results, comparable to other observations in mice or drosophila, show that captive gray mouse lemurs enjoy better fitness when their circadian period closely matches the environmental periodicity. In addition to their deep implications in health and aging research, these results raise further ecological and evolutionary issues regarding the relationships between fitness and circadian clock.

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The Influence of Light Exposure in Ambiance during Pregnancy in Maternal and Fetal Outcomes: An Experimental Study

Revista Brasileira de Ginecologia e Obstetrícia / RBGO Gynecology and Obstetrics ◽

10.1055/s-0038-1675610 ◽

2018 ◽

Vol 41 (01) ◽

pp. 024-030

Author(s):

Vitor Sarri ◽

Beatriz Ferrari ◽

Larissa Magalhães ◽

Paula Rodrigues ◽

Almir Rezende ◽

...

Keyword(s):

Light Exposure ◽

Good Practice ◽

Histological Evaluation ◽

Reproductive Parameters ◽

Anthropometric Measures ◽

Dark Light ◽

Mean Values ◽

Lighting Conditions ◽

Significant Difference ◽

Environmental Lighting

Objective The aim of this study is to evaluate whether exposure to different environmental lighting conditions affects the reproductive parameters of pregnant mice and the development of their offspring. Methods Fifteen pregnant albino mice were divided into three groups: light/dark, light, and dark. The animals were euthanized on day 18 of pregnancy following the Brazilian Good Practice Guide for Euthanasia of Animals. Maternal and fetal specimens were measured and collected for histological evaluation. Analysis of variance (ANOVA) test was used for comparison of the groups considering p ≤ 0.05 to be statistically significant. Results There was no significant difference in the maternal variables between the three groups. Regarding fetal variables, significant differences were observed in the anthropometric measures between the groups exposed to different environmental lighting conditions, with the highest mean values in the light group. The histological evaluation showed the same structural pattern of the placenta in all groups, which was within the normal range. However, evaluation of the uterus revealed a discrete to moderate number of endometrial glands in the light/dark and light groups, which were poorly developed in most animals. In the fetuses, pulmonary analysis revealed morphological features consistent with the transition from the canalicular to the saccular phase in all groups. Conclusion Exposure to different environmental lighting conditions had no influence on the reproductive parameters of female mice, while the offspring of mothers exposed to light for 24 hours exhibited better morphometric features.

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Multi-Modal Regulation of Circadian Physiology by Interactive Features of Biological Clocks

Biology ◽

10.3390/biology11010021 ◽

2021 ◽

Vol 11 (1) ◽

pp. 21

Author(s):

Yool Lee ◽

Jonathan P. Wisor

Keyword(s):

Circadian Clock ◽

Neurological Diseases ◽

Night Shift ◽

Hormone Secretion ◽

Local Environment ◽

Biological Clocks ◽

Tightly Coupled ◽

Peripheral Clocks ◽

Living Organisms ◽

Circadian Physiology

The circadian clock is a fundamental biological timing mechanism that generates nearly 24 h rhythms of physiology and behaviors, including sleep/wake cycles, hormone secretion, and metabolism. Evolutionarily, the endogenous clock is thought to confer living organisms, including humans, with survival benefits by adapting internal rhythms to the day and night cycles of the local environment. Mirroring the evolutionary fitness bestowed by the circadian clock, daily mismatches between the internal body clock and environmental cycles, such as irregular work (e.g., night shift work) and life schedules (e.g., jet lag, mistimed eating), have been recognized to increase the risk of cardiac, metabolic, and neurological diseases. Moreover, increasing numbers of studies with cellular and animal models have detected the presence of functional circadian oscillators at multiple levels, ranging from individual neurons and fibroblasts to brain and peripheral organs. These oscillators are tightly coupled to timely modulate cellular and bodily responses to physiological and metabolic cues. In this review, we will discuss the roles of central and peripheral clocks in physiology and diseases, highlighting the dynamic regulatory interactions between circadian timing systems and multiple metabolic factors.

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PREMONition: An algorithm for predicting the circadian clock-regulated molecular network

10.1101/463190 ◽

2018 ◽

Cited By ~ 1

Author(s):

Jasper Bosman ◽

Zheng Eelderink-Chen ◽

Emma Laing ◽

Martha Merrow

Keyword(s):

Circadian Clock ◽

Clock Gene ◽

Clock Genes ◽

Circadian Clocks ◽

Model Systems ◽

Functional Relationships ◽

Growth Assay ◽

Living Organisms ◽

Clock Mechanism ◽

Transcriptional Feedback

AbstractA transcriptional feedback loop is central to clock function in animals, plants and fungi. The clock genes involved in its regulation are specific to - and highly conserved within - the kingdoms of life. However, other shared clock mechanisms, such as phosphorylation, are mediated by proteins found broadly among living organisms, performing functions in many cellular sub-systems. Use of homology to directly infer involvement/association with the clock mechanism in new, developing model systems, is therefore of limited use. Here we describe the approach PREMONition,PREdictingMolecularNetworks, that uses functional relationships to predict molecular circadian clock associations. PREMONition is based on the incorporation of proteins encoded by known clock genes (when available), rhythmically expressed clock-controlled genes and non-rhythmically expressed but interacting genes into a cohesive network. After tuning PREMONition on the networks derived for human, fly and fungal circadian clocks, we deployed the approach to predict a molecular clock network forSaccharomyces cerevisiae, for which there are no readily-identifiable clock gene homologs. The predicted network was validated using gene expression data and a growth assay for sensitivity to light, a zeitgeber of circadian clocks of most organisms. PREMONition may be used to identify candidate clock-regulated processes and thus candidate clock genes in other organisms.

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Facultative sociality in a subterranean rodent, the highland tuco-tuco (Ctenomys opimus)

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blaa011 ◽

2020 ◽

Vol 129 (4) ◽

pp. 918-930 ◽

Cited By ~ 1

Author(s):

Shannon L O’Brien ◽

Mauro N Tammone ◽

Pablo A Cuello ◽

Eileen A Lacey

Keyword(s):

Social Organization ◽

Social Relationships ◽

Subterranean Rodents ◽

Social Meaning ◽

Subterranean Rodent ◽

Nest Sites ◽

The Social ◽

Below Ground ◽

Number Of Individuals ◽

Facultative Sociality

Abstract Understanding why social relationships vary among conspecifics is central to studies of animal behaviour. For many species, patterns of space use provide important insights into social behaviour. To characterize the social organization of the highland tuco-tuco (Ctenomys opimus), we used visual observations and radiotelemetry to quantify spatial relationships among adults in a population at Laguna de los Pozuelos, Jujuy Province, Argentina. Specifically, we sought to confirm anecdotal reports that these subterranean rodents are social, meaning that adults share burrow systems and nest sites. Our data indicate that the animals live in spatially distinct groups, although the number of individuals per group varies markedly. Although these relationships were robust with regard to location (above vs. below ground) and type of data (visual vs. telemetry), some groups identified during the daytime fissioned during the night. We suggest that the population of C. opimus at Pozuelos is facultatively social, meaning that individuals display predictable, adaptive differences in social relationships with conspecifics. More generally, our findings add to the growing number of subterranean species of rodents recognized as social, thereby generating new opportunities for comparative studies of these animals aimed at assessing the causes and consequences of variation in social organization.

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Familiarity and mating behavior in the subterranean rodent Ctenomys talarum (tuco-tuco)

Canadian Journal of Zoology ◽

10.1139/z07-078 ◽

2007 ◽

Vol 85 (9) ◽

pp. 944-955 ◽

Cited By ~ 11

Author(s):

Roxana R. Zenuto ◽

Candelaria Estavillo ◽

María Sol Fanjul

Keyword(s):

Mating Behavior ◽

Mate Selection ◽

Individual Recognition ◽

Scent Mark ◽

Subterranean Rodents ◽

Subterranean Rodent ◽

Odor Cues ◽

Mating Costs ◽

Neighbor Recognition ◽

Ctenomys Talarum

Biological odors that convey cues regarding individual identity are known to alter mating behavior in some rodents. Deposition of chemical signals by males on the substrate could give females information about their neighbors’ identity and allow familiarization with their odors. This study tested whether familiarization of females with conspecific male odors affects mating behavior in Ctenomys talarum Thomas, 1898, facilitating mating as a consequence of a decrease in aggressive behavior and an increase in sexual behavior. Tuco-tucos are solitary subterranean rodents that occupy and defend adjacent burrows. Both sexes usually scent-mark burrow openings, providing odor signals to neighbors during their aboveground patrolling and foraging activities. Hence, familiarity by odor cues may represent an important mechanism that mediates neighbor recognition and probably mate selection. In this study, familiarity was established by housing females with male odors for 8 days. In C. talarum, individual recognition by olfactory cues may reduce mating costs when pairing with neighbors, since females showed low aggression towards familiar males and copulations were not repeated in consecutive days. Females that were not exposed to male odors were more aggressive, but surprisingly these pairs copulated repeatedly.

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Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1418490112 ◽

2014 ◽

Vol 112 (4) ◽

pp. 1232-1237 ◽

Cited By ~ 433

Author(s):

Anne-Marie Chang ◽

Daniel Aeschbach ◽

Jeanne F. Duffy ◽

Charles A. Czeisler

Keyword(s):

Circadian Clock ◽

Technology Use ◽

Negative Impact ◽

Light Exposure ◽

Biological Effects ◽

Biological Clock ◽

Health And Safety ◽

Light Emitting ◽

Circadian Phase ◽

The Impact

In the past 50 y, there has been a decline in average sleep duration and quality, with adverse consequences on general health. A representative survey of 1,508 American adults recently revealed that 90% of Americans used some type of electronics at least a few nights per week within 1 h before bedtime. Mounting evidence from countries around the world shows the negative impact of such technology use on sleep. This negative impact on sleep may be due to the short-wavelength–enriched light emitted by these electronic devices, given that artificial-light exposure has been shown experimentally to produce alerting effects, suppress melatonin, and phase-shift the biological clock. A few reports have shown that these devices suppress melatonin levels, but little is known about the effects on circadian phase or the following sleep episode, exposing a substantial gap in our knowledge of how this increasingly popular technology affects sleep. Here we compare the biological effects of reading an electronic book on a light-emitting device (LE-eBook) with reading a printed book in the hours before bedtime. Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock, and reduced next-morning alertness than when reading a printed book. These results demonstrate that evening exposure to an LE-eBook phase-delays the circadian clock, acutely suppresses melatonin, and has important implications for understanding the impact of such technologies on sleep, performance, health, and safety.

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