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Oda GA, Valentinuzzi VS. A clock for all seasons in the subterranean. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:677-689. [PMID: 37815602 DOI: 10.1007/s00359-023-01677-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 09/14/2023] [Accepted: 10/02/2023] [Indexed: 10/11/2023]
Abstract
In 1976, Pittendrigh and Daan established a theoretical framework which has coordinated research on circadian clock entrainment and photoperiodism until today. The "wild clocks" approach, which concerns studying wild species in their natural habitats, has served to test their models, add new insights, and open new directions of research. Here, we review an integrated laboratory, field and modeling work conducted with subterranean rodents (Ctenomys sp.) living under an extreme pattern of natural daily light exposure. Tracking animal movement and light exposure with biologgers across seasons and performing laboratory experiments on running-wheel cages, we uncovered the mechanisms of day/night entrainment of the clock and of photoperiodic time measurement in this subterranean organism. We confirmed most of the features of Pittendrigh and Daan's models but highlighted the importance of integrating them with ecophysiological techniques, methodologies, and theories to get a full picture of the clock in the wild. This integration is essential to fully establish the importance of the temporal dimension in ecological studies and tackling relevant questions such as the role of the clock for all seasons in a changing planet.
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Affiliation(s)
- Gisele A Oda
- Laboratório Binacional de Cronobiologia, Universidade de São Paulo, São Paulo, SP, Brazil.
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2
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Häfker NS, Holcik L, Mat AM, Ćorić A, Vadiwala K, Beets I, Stockinger AW, Atria CE, Hammer S, Revilla-i-Domingo R, Schoofs L, Raible F, Tessmar-Raible K. Molecular circadian rhythms are robust in marine annelids lacking rhythmic behavior. PLoS Biol 2024; 22:e3002572. [PMID: 38603542 PMCID: PMC11008795 DOI: 10.1371/journal.pbio.3002572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/29/2024] [Indexed: 04/13/2024] Open
Abstract
The circadian clock controls behavior and metabolism in various organisms. However, the exact timing and strength of rhythmic phenotypes can vary significantly between individuals of the same species. This is highly relevant for rhythmically complex marine environments where organismal rhythmic diversity likely permits the occupation of different microenvironments. When investigating circadian locomotor behavior of Platynereis dumerilii, a model system for marine molecular chronobiology, we found strain-specific, high variability between individual worms. The individual patterns were maintained for several weeks. A diel head transcriptome comparison of behaviorally rhythmic versus arrhythmic wild-type worms showed that 24-h cycling of core circadian clock transcripts is identical between both behavioral phenotypes. While behaviorally arrhythmic worms showed a similar total number of cycling transcripts compared to their behaviorally rhythmic counterparts, the annotation categories of their transcripts, however, differed substantially. Consistent with their locomotor phenotype, behaviorally rhythmic worms exhibit an enrichment of cycling transcripts related to neuronal/behavioral processes. In contrast, behaviorally arrhythmic worms showed significantly increased diel cycling for metabolism- and physiology-related transcripts. The prominent role of the neuropeptide pigment-dispersing factor (PDF) in Drosophila circadian behavior prompted us to test for a possible functional involvement of Platynereis pdf. Differing from its role in Drosophila, loss of pdf impacts overall activity levels but shows only indirect effects on rhythmicity. Our results show that individuals arrhythmic in a given process can show increased rhythmicity in others. Across the Platynereis population, rhythmic phenotypes exist as a continuum, with no distinct "boundaries" between rhythmicity and arrhythmicity. We suggest that such diel rhythm breadth is an important biodiversity resource enabling the species to quickly adapt to heterogeneous or changing marine environments. In times of massive sequencing, our work also emphasizes the importance of time series and functional tests.
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Affiliation(s)
- N. Sören Häfker
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Laurenz Holcik
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
- Center for Integrative Bioinformatics Vienna, Max Perutz Labs, University of Vienna, Medical University of Vienna, Vienna, Austria
| | - Audrey M. Mat
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Aida Ćorić
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Karim Vadiwala
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Isabel Beets
- Division of animal Physiology and Neurobiology, KU Leuven, Leuven, Belgium
| | - Alexander W. Stockinger
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Carolina E. Atria
- Department of Neuro- and Developmental Biology, University of Vienna, Vienna, Austria
- Research Platform Single-Cell Regulation of Stem Cells, University of Vienna, Vienna, Austria
| | - Stefan Hammer
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Roger Revilla-i-Domingo
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
- Department of Neuro- and Developmental Biology, University of Vienna, Vienna, Austria
- Research Platform Single-Cell Regulation of Stem Cells, University of Vienna, Vienna, Austria
| | - Liliane Schoofs
- Division of animal Physiology and Neurobiology, KU Leuven, Leuven, Belgium
| | - Florian Raible
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Kristin Tessmar-Raible
- Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
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3
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Jannetti MG, Tachinardi P, Valentinuzzi VS, Oda GA. Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent ( Ctenomys famosus) in Field Enclosures. J Biol Rhythms 2023:7487304231154715. [PMID: 36924450 DOI: 10.1177/07487304231154715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Several wild rodents, such as the subterranean tuco-tucos (Ctenomys famosus), switch their time of activity from diurnal to nocturnal when they are transferred from field to the laboratory. Nevertheless, in most studies, different methods to measure activity in each of these conditions were used, which raised the question of whether the detected change in activity timing could be an artifact. Because locomotor activity and body temperature (Tb) rhythms in rodents are tightly synchronized and because abdominal Tb loggers can provide continuous measurements across field and laboratory, we monitored Tb as a proxy of activity in tuco-tucos transferred from a semi-field enclosure to constant lab conditions. In the first stage of this study ("Tb-only group," 2012-2016), we verified high incidence (55%, n = 20) of arrhythmicity, with no consistent diurnal Tb rhythms in tuco-tucos maintained under semi-field conditions. Because these results were discrepant from subsequent findings using miniature accelerometers (portable activity loggers), which showed diurnal activity patterns in natural conditions (n = 10, "Activity-only group," 2016-2017), we also investigated, in the present study, whether the tight association between activity and Tb would be sustained outside the lab. To verify this, we measured activity and Tb simultaneously across laboratory and semi-field deploying both accelerometers and Tb loggers to each animal. These measurements (n = 11, "Tb + activity group," 2019-2022) confirmed diurnality of locomotor activity and revealed an unexpected loosening of the temporal association between Tb and activity rhythms in the field enclosures, which is otherwise robustly tight in the laboratory.
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Affiliation(s)
- Milene G Jannetti
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Patricia Tachinardi
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Veronica S Valentinuzzi
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Centro Regional de Investigaciones Cientificas y de Transferencia Tecnológica (CRILAR), Anillaco, Argentina
| | - Gisele A Oda
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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Häfker NS, Connan-McGinty S, Hobbs L, McKee D, Cohen JH, Last KS. Animal behavior is central in shaping the realized diel light niche. Commun Biol 2022; 5:562. [PMID: 35676530 PMCID: PMC9177748 DOI: 10.1038/s42003-022-03472-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/10/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractAnimal behavior in space and time is structured by the perceived day/night cycle. However, this is modified by the animals’ own movement within its habitat, creating a realized diel light niche (RDLN). To understand the RDLN, we investigated the light as experienced by zooplankton undergoing synchronized diel vertical migration (DVM) in an Arctic fjord around the spring equinox. We reveal a highly dampened light cycle with diel changes being about two orders of magnitude smaller compared to the surface or a static depth. The RDLN is further characterized by unique wavelength-specific irradiance cycles. We discuss the relevance of RDLNs for animal adaptations and interactions, as well as implications for circadian clock entrainment in the wild and laboratory.
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Improta GC, Flôres DEFL, Oda GA, Valentinuzzi VS. Daylength Shapes Entrainment Patterns to Artificial Photoperiods in a Subterranean Rodent. J Biol Rhythms 2022; 37:283-295. [DOI: 10.1177/07487304221085105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Photoperiodism plays an important role in the synchronization of seasonal phenomena in various organisms. In mammals, photoperiod encoding is mediated by differential entrainment of the circadian system. The limits of daily light entrainment and photoperiodic time measurement can be verified in organisms that inhabit extreme photic environments, such as the subterranean. In this experimental study, we evaluated entrainment of circadian wheel-running rhythms in South American subterranean rodents, the Anillaco tuco-tucos ( Ctenomys aff. knighti), exposed to different artificial photoperiods, from extremely long to extremely short photophases (LD 21:3, LD 18:6, LD 15:9, LD 9:15, LD 6:18 and LD 3:21). Artificial photoperiods synchronized their activity/rest rhythms and clear differences occurred in (a) phase angles of entrainment relative to the LD cycle and (b) duration of the daily activity phase α. These photoperiod-dependent patterns of entrainment were similar to those reported for epigeous species. Release into constant darkness conditions revealed aftereffects of entrainment to different photoperiods, observed in α but not in the free-running period τ. We also verified if animals coming from summer and winter natural photoperiods entrained equally to the artificial photoperiods by evaluating their phase angle of entrainment, α and τ aftereffects. To this end, experimental animals were divided into “Matching” and “Mismatching” groups, based on whether the experimental photoperiod (short-day [L < 12 h] or long-day [L > 12 h]) matched or not the natural photoperiod to which they had been previously exposed. No significant differences were found in the phase angle of entrainment, α and τ aftereffects in each artificial photoperiod. Our results indicate that the circadian clocks of tuco-tucos are capable of photoperiodic time measurement despite their natural subterranean habits and that the final entrainment patterns achieved by the circadian clock do not depend on the photoperiodic history.
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Affiliation(s)
- Giovane Carreira Improta
- Laboratóriode Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Danilo Eugênio França Laurindo Flôres
- Laboratóriode Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Gisele Akemi Oda
- Laboratóriode Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil
| | - Verónica Sandra Valentinuzzi
- Laboratorio de Cronobiología Binacional Argentina-Brasil, Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja, Anillaco, Argentina
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Cohen JH, Last KS, Charpentier CL, Cottier F, Daase M, Hobbs L, Johnsen G, Berge J. Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night. PLoS Biol 2021; 19:e3001413. [PMID: 34665816 PMCID: PMC8525745 DOI: 10.1371/journal.pbio.3001413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/16/2021] [Indexed: 11/18/2022] Open
Abstract
Light plays a fundamental role in the ecology of organisms in nearly all habitats on Earth and is central for processes such as vision and the entrainment of the circadian clock. The poles represent extreme light regimes with an annual light cycle including periods of Midnight Sun and Polar Night. The Arctic Ocean extends to the North Pole, and marine light extremes reach their maximum extent in this habitat. During the Polar Night, traditional definitions of day and night and seasonal photoperiod become irrelevant since there are only "twilight" periods defined by the sun's elevation below the horizon at midday; we term this "midday twilight." Here, we characterize light across a latitudinal gradient (76.5° N to 81° N) during Polar Night in January. Our light measurements demonstrate that the classical solar diel light cycle dominant at lower latitudes is modulated during Arctic Polar Night by lunar and auroral components. We therefore question whether this particular ambient light environment is relevant to behavioral and visual processes. We reveal from acoustic field observations that the zooplankton community is undergoing diel vertical migration (DVM) behavior. Furthermore, using electroretinogram (ERG) recording under constant darkness, we show that the main migratory species, Arctic krill (Thysanoessa inermis) show endogenous increases in visual sensitivity during the subjective night. This change in sensitivity is comparable to that under exogenous dim light acclimations, although differences in speed of vision suggest separate mechanisms. We conclude that the extremely weak midday twilight experienced by krill at high latitudes during the darkest parts of the year has physiological and ecological relevance.
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Affiliation(s)
- Jonathan H. Cohen
- School of Marine Science & Policy, University of Delaware, Lewes, Delaware, United States of America
- * E-mail:
| | - Kim S. Last
- Scottish Association for Marine Science, Oban, United Kingdom
| | - Corie L. Charpentier
- Department of Biology, Stetson University, DeLand, Florida, United States of America
| | - Finlo Cottier
- Scottish Association for Marine Science, Oban, United Kingdom
- UiT, The Arctic University of Norway, Faculty for Biosciences, Fisheries and Economics, Department for Arctic and Marine Biology, Tromsø, Norway
| | - Malin Daase
- UiT, The Arctic University of Norway, Faculty for Biosciences, Fisheries and Economics, Department for Arctic and Marine Biology, Tromsø, Norway
| | - Laura Hobbs
- Scottish Association for Marine Science, Oban, United Kingdom
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, United Kingdom
| | - Geir Johnsen
- University Centre in Svalbard, Longyearbyen, Norway
- Centre of Autonomous Marine Operations and Systems, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jørgen Berge
- UiT, The Arctic University of Norway, Faculty for Biosciences, Fisheries and Economics, Department for Arctic and Marine Biology, Tromsø, Norway
- University Centre in Svalbard, Longyearbyen, Norway
- Centre of Autonomous Marine Operations and Systems, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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Flôres DEFL, Jannetti MG, Improta GC, Tachinardi P, Valentinuzzi VS, Oda GA. Telling the Seasons Underground: The Circadian Clock and Ambient Temperature Shape Light Exposure and Photoperiodism in a Subterranean Rodent. Front Physiol 2021; 12:738471. [PMID: 34658922 PMCID: PMC8517108 DOI: 10.3389/fphys.2021.738471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/10/2021] [Indexed: 11/13/2022] Open
Abstract
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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Affiliation(s)
- Danilo E F L Flôres
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Milene G Jannetti
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Giovane C Improta
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Patricia Tachinardi
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Veronica S Valentinuzzi
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Centro Regional de Investigaciones Cientificas y de Transferencia Tecnológica (CRILAR), Anillaco, Argentina
| | - Gisele A Oda
- Laboratorio de Cronobiologia Binacional Argentina-Brasil, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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8
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Wong KY, Fernandez FX. Circadian Responses to Light-Flash Exposure: Conceptualization and New Data Guiding Future Directions. Front Neurol 2021; 12:627550. [PMID: 33643205 PMCID: PMC7905211 DOI: 10.3389/fneur.2021.627550] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/21/2021] [Indexed: 01/03/2023] Open
Abstract
A growing number of studies document circadian phase-shifting after exposure to millisecond light flashes. When strung together by intervening periods of darkness, these stimuli evoke pacemaker responses rivaling or outmatching those created by steady luminance, suggesting that the circadian system's relationship to light can be contextualized outside the principle of simple dose-dependence. In the current review, we present a brief chronology of this work. We then develop a conceptual model around it that attempts to relate the circadian effects of flashes to a natural integrative process the pacemaker uses to intermittently sample the photic information available at dawn and dusk. Presumably, these snapshots are employed as building blocks in the construction of a coherent representation of twilight the pacemaker consults to orient the next day's physiology (in that way, flash-resetting of pacemaker rhythms might be less an example of a circadian visual illusion and more an example of the kinds of gestalt inferences that the image-forming system routinely makes when identifying objects within the visual field; i.e., closure). We conclude our review with a discussion on the role of cones in the pacemaker's twilight predictions, providing new electrophysiological data suggesting that classical photoreceptors—but not melanopsin—are necessary for millisecond, intermediate-intensity flash responses in ipRGCs (intrinsically photosensitive retinal ganglion cells). Future investigations are necessary to confirm this “Cone Sentinel Model” of circadian flash-integration and twilight-prediction, and to further define the contribution of cones vs. rods in transducing pacemaker flash signals.
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Affiliation(s)
- Kwoon Y Wong
- Department of Molecular, Cellular, & Developmental Biology, University of Michigan, Ann Arbor, MI, United States.,Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, MI, United States
| | - Fabian-Xosé Fernandez
- Department of Psychology, BIO5 Research Institute, University of Arizona, Tucson, AZ, United States.,Department of Neurology, McKnight Brain Research Institute, University of Arizona, Tucson, AZ, United States
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9
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Miranda V, Sede S, Aranda-Rickert A, Rothen C, Scervino JM, Barros J, Fracchia S. Taxonomy, life cycle and endophytism of coprophilous fungi from an underground desert rodent. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2019.100872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Yassumoto TI, Tachinardi P, Oda GA, Valentinuzzi VS. Acute effects of light and darkness on the activity and temperature rhythms of a subterranean rodent, the Anillaco tuco-tuco. Physiol Behav 2019; 210:112645. [DOI: 10.1016/j.physbeh.2019.112645] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 11/30/2022]
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Jannetti MG, Buck CL, Valentinuzzi VS, Oda GA. Day and night in the subterranean: measuring daily activity patterns of subterranean rodents ( Ctenomys aff. knighti) using bio-logging. CONSERVATION PHYSIOLOGY 2019; 7:coz044. [PMID: 31341624 PMCID: PMC6640163 DOI: 10.1093/conphys/coz044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 06/11/2019] [Accepted: 06/17/2019] [Indexed: 06/10/2023]
Abstract
While most studies of the impacts of climate change have investigated shifts in the spatial distribution of organisms, temporal shifts in the time of activity is another important adjustment made by animals in a changing world. Due to the importance of light and temperature cycles in shaping activity patterns, studies of activity patterns of organisms that inhabit extreme environments with respect to the 24-hour cyclicity of Earth have the potential to provide important insights into the interrelationships among abiotic variables, behaviour and physiology. Our previous laboratory studies with Argentinean tuco-tucos from the Monte desert (Ctenomys aff. knighti) show that these subterranean rodents display circadian activity/rest rhythms that can be synchronized by artificial light/dark cycles. Direct observations indicate that tuco-tucos emerge mainly for foraging and for removal of soil from their burrows. Here we used bio-logging devices for individual, long-term recording of daily activity/rest (accelerometry) and time on surface (light-loggers) of six tuco-tucos maintained in outdoor semi-natural enclosures. Environmental variables were measured simultaneously. Activity bouts were detected both during day and night but 77% of the highest values happened during the daytime and 47% of them coincided with time on surface. Statistical analyses indicate time of day and temperature as the main environmental factors modulating time on surface. In this context, the total duration that these subterranean animals spent on surface was high during the winter, averaging 3 h per day and time on surface occurred when underground temperature was lowest. Finally, transport of these animals to the indoor laboratory and subsequent assessment of their activity rhythms under constant darkness revealed a switch in the timing of activity. Plasticity of activity timing is not uncommon among desert rodents and may be adaptive in changing environments, such as the desert where this species lives.
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Affiliation(s)
- Milene G Jannetti
- Laboratorio Binacional Argentina-Brasil de Cronobiologia, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Veronica S Valentinuzzi
- Laboratorio Binacional Argentina-Brasil de Cronobiologia, Centro Regional de Investigaciones Cientificas y Transferencia Tecnológica (CRILAR), Entre Ríos y Mendoza, s/n, Anillaco, La Rioja, Argentina
| | - Gisele A Oda
- Laboratorio Binacional Argentina-Brasil de Cronobiologia, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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Flôres DEFL, Oda GA. Novel Light/Dark Regimens with Minimum Light Promote Circadian Disruption: Simulations with a Model Oscillator. J Biol Rhythms 2018; 34:105-110. [DOI: 10.1177/0748730418820727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | - Gisele A. Oda
- Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil
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13
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Tachinardi P, Valentinuzzi VS, Oda GA, Buck CL. The Interplay of Energy Balance and Daily Timing of Activity in a Subterranean Rodent: A Laboratory and Field Approach. Physiol Biochem Zool 2017; 90:546-552. [PMID: 28665185 DOI: 10.1086/693003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The tuco-tuco (Ctenomys aff. knighti) is among the rodent species known to be nocturnal under standard laboratory conditions and diurnal under natural conditions. The circadian thermoenergetics (CTE) hypothesis postulates that switches in activity timing are a response to energetic challenges; daytime activity reduces thermoregulatory costs by consolidating activity to the warmest part of the day. Studying wild animals under both captive and natural conditions can increase understanding of how temporal activity patterns are shaped by the environment and could serve as a test of the CTE hypothesis. We estimated the effects of activity timing on energy expenditure for the tuco-tuco by combining laboratory measurements of metabolic rate with environmental temperature records in both winter and summer. We showed that, in winter, there would be considerable energy savings if activity is allocated at least partially during daylight, lending support to the CTE hypothesis. In summer, the impact of activity timing on energy expenditure is small, suggesting that during this season other factors, such as predation risk, water balance, and social interaction, may have more important roles than energetics in the determination of activity time.
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