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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 2023:10.1007/s00359-023-01677-z. [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] [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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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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3
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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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4
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Mammola S, Amorim IR, Bichuette ME, Borges PAV, Cheeptham N, Cooper SJB, Culver DC, Deharveng L, Eme D, Ferreira RL, Fišer C, Fišer Ž, Fong DW, Griebler C, Jeffery WR, Jugovic J, Kowalko JE, Lilley TM, Malard F, Manenti R, Martínez A, Meierhofer MB, Niemiller ML, Northup DE, Pellegrini TG, Pipan T, Protas M, Reboleira ASPS, Venarsky MP, Wynne JJ, Zagmajster M, Cardoso P. Fundamental research questions in subterranean biology. Biol Rev Camb Philos Soc 2020; 95:1855-1872. [DOI: 10.1111/brv.12642] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Stefano Mammola
- Laboratory for Integrative Biodiversity Research (LIBRe), Finnish Museum of Natural History (LUOMUS) University of Helsinki Pohjoinen Rautatiekatu 13 Helsinki 00100 Finland
- Molecular Ecology Group (MEG) Water Research Institute (IRSA), National Research Council (CNR) Corso Tonolli, 50 Pallanza 28922 Italy
| | - Isabel R. Amorim
- cE3c – Centre for Ecology Evolution and Environmental Changes/Azorean Biodiversity Group and Universidade dos Açores, Faculty of Agrarian and Environmental Sciences, Rua Capitão João d'Àvila Pico da Urze Angra do Heroísmo Azores 9700‐042 Portugal
| | - Maria E. Bichuette
- Laboratory of Subterranean Studies Federal University of São Carlos Rodovia Washington Luís km 235 São Carlos São Paulo 13565‐905 Brazil
| | - Paulo A. V. Borges
- cE3c – Centre for Ecology Evolution and Environmental Changes/Azorean Biodiversity Group and Universidade dos Açores, Faculty of Agrarian and Environmental Sciences, Rua Capitão João d'Àvila Pico da Urze Angra do Heroísmo Azores 9700‐042 Portugal
| | - Naowarat Cheeptham
- Department of Biological Sciences, Faculty of Science Thompson Rivers University 805 TRU Way Kamloops British Columbia Canada
| | - Steven J. B. Cooper
- Evolutionary Biology Unit South Australian Museum North Terrace Adelaide South Australia 5000 Australia
- Australian Centre for Evolutionary Biology and Biodiversity, and Environment Institute, School of Biological Sciences University of Adelaide Adelaide South Australia 5005 Australia
| | - David C. Culver
- Department of Environmental Science American University 4400 Massachusetts Avenue, N.W. Washington DC 20016 U.S.A
| | - Louis Deharveng
- UMR7205 – ISYEB Museum national d'Histoire naturelle 45 rue Buffon (CP50) Paris 75005 France
| | - David Eme
- IFREMER Centre Atlantique Unité Ecologie et Modèles pour l'Halieutique Rue de l'Île d'Yeu Nantes 44980 France
| | - Rodrigo Lopes Ferreira
- Center of Studies in Subterranean Biology, Biology Department Federal University of Lavras Campus Universitário Lavras Minas Gerais CEP 37202‐553 Brazil
| | - Cene Fišer
- SubBio Lab, Department of Biology, Biotechnical Faculty University of Ljubljana Jamnikarjeva 101, PO BOX 2995 Ljubljana SI‐1000 Slovenia
| | - Žiga Fišer
- SubBio Lab, Department of Biology, Biotechnical Faculty University of Ljubljana Jamnikarjeva 101, PO BOX 2995 Ljubljana SI‐1000 Slovenia
| | - Daniel W. Fong
- Department of Biology American University 4400 Massachusetts Avenue, N.W. Washington DC 20016 U.S.A
| | - Christian Griebler
- Department of Functional and Evolutionary Ecology, Division of Limnology University of Vienna Althanstrasse 14 Vienna 1090 Austria
| | - William R. Jeffery
- Department of Biology University of Maryland College Park MD 20742 U.S.A
| | - Jure Jugovic
- Department of Biodiversity, Faculty of Mathematics, Natural Sciences and Information Technologies University of Primorska Glagoljaška 8 Koper SI‐6000 Slovenia
| | - Johanna E. Kowalko
- Harriet L. Wilkes Honors College Florida Atlantic University 5353 Parkside Dr Jupiter FL 33458 U.S.A
| | - Thomas M. Lilley
- BatLab Finland, Finnish Museum of Natural History University of Helsinki Pohjoinen Rautatiekatu 13 Helsinki 00100 Finland
| | - Florian Malard
- UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés Univ. Lyon 1, ENTPE, CNRS, Université de Lyon, Bat. Forel 6 rue Raphaël Dubois Villeurbanne cedex 69622 France
| | - Raoul Manenti
- Department of Environmental Science and Policy Università degli Studi di Milano Via Celoria 26 Milan 20113 Italy
| | - Alejandro Martínez
- Molecular Ecology Group (MEG) Water Research Institute (IRSA), National Research Council (CNR) Corso Tonolli, 50 Pallanza 28922 Italy
| | - Melissa B. Meierhofer
- BatLab Finland, Finnish Museum of Natural History University of Helsinki Pohjoinen Rautatiekatu 13 Helsinki 00100 Finland
- Department of Rangeland, Wildlife and Fisheries Management Texas A&M University 534 John Kimbrough Blvd. College Station TX 77843 U.S.A
| | - Matthew L. Niemiller
- Department of Biological Sciences The University of Alabama in Huntsville 301 Sparkman Drive NW Huntsville AL 35899 U.S.A
| | - Diana E. Northup
- Department of Biology University of New Mexico Albuquerque NM 87131‐0001 U.S.A
| | - Thais G. Pellegrini
- Center of Studies in Subterranean Biology, Biology Department Federal University of Lavras Campus Universitário Lavras Minas Gerais CEP 37202‐553 Brazil
| | - Tanja Pipan
- ZRC SAZU Karst Research Institute Novi trg 2 Ljubljana SI‐1000 Slovenia
- UNESCO Chair on Karst Education University of Nova Gorica Vipavska cesta Nova Gorica 5000 Slovenia
| | - Meredith Protas
- Department of Natural Sciences and Mathematics Domenicas University of California 50 Acacia Avenue San Rafael CA 94901 U.S.A
| | - Ana Sofia P. S. Reboleira
- Natural History Museum of Denmark University of Copenhagen Universitetsparken 15 Copenhagen 2100 Denmark
| | - Michael P. Venarsky
- Australian Rivers Institute Griffith University 170 Kessels Road Nathan Queensland 4111 Australia
| | - J. Judson Wynne
- Department of Biological Sciences, Center for Adaptable Western Landscapes Northern Arizona University Box 5640 Flagstaff AZ 86011 U.S.A
| | - Maja Zagmajster
- SubBio Lab, Department of Biology, Biotechnical Faculty University of Ljubljana Jamnikarjeva 101, PO BOX 2995 Ljubljana SI‐1000 Slovenia
| | - Pedro Cardoso
- Laboratory for Integrative Biodiversity Research (LIBRe), Finnish Museum of Natural History (LUOMUS) University of Helsinki Pohjoinen Rautatiekatu 13 Helsinki 00100 Finland
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5
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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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7
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Flôres DEFL, Jannetti MG, Valentinuzzi VS, Oda GA. Entrainment of circadian rhythms to irregular light/dark cycles: a subterranean perspective. Sci Rep 2016; 6:34264. [PMID: 27698436 PMCID: PMC5048425 DOI: 10.1038/srep34264] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 09/12/2016] [Indexed: 01/31/2023] Open
Abstract
Synchronization of biological rhythms to the 24-hour day/night has long been studied with model organisms, under artificial light/dark cycles in the laboratory. The commonly used rectangular light/dark cycles, comprising hours of continuous light and darkness, may not be representative of the natural light exposure for most species, including humans. Subterranean rodents live in dark underground tunnels and offer a unique opportunity to investigate extreme mechanisms of photic entrainment in the wild. Here, we show automated field recordings of the daily light exposure patterns in a South American subterranean rodent, the tuco-tuco (Ctenomys aff. knighti ). In the laboratory, we exposed tuco-tucos to a simplified version of this natural light exposure pattern, to determine the minimum light timing information that is necessary for synchronization. As predicted from our previous studies using mathematical modeling, the activity rhythm of tuco-tucos synchronized to this mostly simplified light/dark regimen consisting of a single light pulse per day, occurring at randomly scattered times within a day length interval. Our integrated semi-natural, lab and computer simulation findings indicate that photic entrainment of circadian oscillators is robust, even in face of artificially reduced exposure and increased phase instability of the synchronizing stimuli.
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Affiliation(s)
- Danilo E. F. L. Flôres
- Institute of Biosciences, Department of Physiology, University of São Paulo; São Paulo, São Paulo, 05508-900; Brazil
| | - Milene G. Jannetti
- Institute of Biosciences, Department of Physiology, University of São Paulo; São Paulo, São Paulo, 05508-900; Brazil
| | - Veronica S. Valentinuzzi
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR), Provincia de La Rioja, UNLaR, SEGEMAR, UNCa, CONICET. Entre Ríos y Mendoza s/n, (5301) Anillaco, La Rioja, Argentina
| | - Gisele A. Oda
- Institute of Biosciences, Department of Physiology, University of São Paulo; São Paulo, São Paulo, 05508-900; Brazil
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Risau-Gusman S. Effects of time-delayed feedback on the properties of self-sustained oscillators. Phys Rev E 2016; 94:042212. [PMID: 27841595 DOI: 10.1103/physreve.94.042212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Indexed: 06/06/2023]
Abstract
Most self-sustained oscillations in biological systems and in technical applications are based on a feedback loop, and it is usually important to know how they will react when an external oscillatory force is applied. Here we investigate the effects that the introduction of a time delay in the feedback can have in the entrainment properties of self-sustained oscillators. To do this, we derive analytic expressions for the periodic trajectories and their asymptotic stability, for a generic external oscillatory force. This allows us to show that, for large quality factors, the resonance frequency does not depend on the feedback delay. When the external force is harmonic, it is shown that the largest entrainment range does not correspond to the time delay that gives the maximal response of the unforced oscillator. In fact, that delay gives the shortest entrainment range.
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Affiliation(s)
- S Risau-Gusman
- Centro Atómico Bariloche, 8400 S. C. de Bariloche, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
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Tomotani BM, Amaya JP, Oda GA, Valentinuzzi VS. Social modulation of the daily activity rhythm in a solitary subterranean rodent, the tuco-tuco ( Ctenomys sp). Sleep Sci 2016; 9:280-284. [PMID: 28154741 PMCID: PMC5279933 DOI: 10.1016/j.slsci.2016.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/12/2016] [Accepted: 06/20/2016] [Indexed: 11/30/2022] Open
Abstract
South American subterranean rodents are mainly described as solitary and mutual synchronization was never observed among individuals maintained together in laboratory. We report that a single birth event was capable of disrupting the robust nocturnal activity rhythm of singly housed tuco-tucos from north-west Argentina. "Around-the-clock activity" was displayed by 8 out of 13 animals whose cages were closer to the newborn pups. However, experimental exposure to a pup vocalization did not produce a similar effect on the rhythms of adult animals. Our results indicate an effect of social interaction in the expression of biological rhythms even in solitary animals.
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Affiliation(s)
- Barbara Mizumo Tomotani
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo , São Paulo, Brazil
| | - Juan Pablo Amaya
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja, CRILAR-CONICET, Entre Rios y Mendoza s/n, 5301 Anillaco, La Rioja, Argentina
| | - Gisele Akemi Oda
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo , São Paulo, Brazil
| | - Veronica Sandra Valentinuzzi
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja, CRILAR-CONICET, Entre Rios y Mendoza s/n, 5301 Anillaco, La Rioja, Argentina
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Tachinardi P, Tøien Ø, Valentinuzzi VS, Buck CL, Oda GA. Nocturnal to Diurnal Switches with Spontaneous Suppression of Wheel-Running Behavior in a Subterranean Rodent. PLoS One 2015; 10:e0140500. [PMID: 26460828 PMCID: PMC4603895 DOI: 10.1371/journal.pone.0140500] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/25/2015] [Indexed: 01/15/2023] Open
Abstract
Several rodent species that are diurnal in the field become nocturnal in the lab. It has been suggested that the use of running-wheels in the lab might contribute to this timing switch. This proposition is based on studies that indicate feed-back of vigorous wheel-running on the period and phase of circadian clocks that time daily activity rhythms. Tuco-tucos (Ctenomys aff. knighti) are subterranean rodents that are diurnal in the field but are robustly nocturnal in laboratory, with or without access to running wheels. We assessed their energy metabolism by continuously and simultaneously monitoring rates of oxygen consumption, body temperature, general motor and wheel running activity for several days in the presence and absence of wheels. Surprisingly, some individuals spontaneously suppressed running-wheel activity and switched to diurnality in the respirometry chamber, whereas the remaining animals continued to be nocturnal even after wheel removal. This is the first report of timing switches that occur with spontaneous wheel-running suppression and which are not replicated by removal of the wheel.
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Affiliation(s)
| | - Øivind Tøien
- Institute of Arctic Biology, University of Alaska, Fairbanks, United States of America
| | - Veronica S. Valentinuzzi
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica (CRILAR), La Rioja, Argentina
| | - C. Loren Buck
- Department of Biological Sciences, University of Alaska, Anchorage, United States of America
| | - Gisele A. Oda
- Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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11
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Tachinardi P, Bicudo JEW, Oda GA, Valentinuzzi VS. Rhythmic 24 h variation of core body temperature and locomotor activity in a subterranean rodent (Ctenomys aff. knighti), the tuco-tuco. PLoS One 2014; 9:e85674. [PMID: 24454916 PMCID: PMC3893220 DOI: 10.1371/journal.pone.0085674] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/05/2013] [Indexed: 11/19/2022] Open
Abstract
The tuco-tuco Ctenomys aff. knighti is a subterranean rodent which inhabits a semi-arid area in Northwestern Argentina. Although they live in underground burrows where environmental cycles are attenuated, they display robust, 24 h locomotor activity rhythms that are synchronized by light/dark cycles, both in laboratory and field conditions. The underground environment also poses energetic challenges (e.g. high-energy demands of digging, hypoxia, high humidity, low food availability) that have motivated thermoregulation studies in several subterranean rodent species. By using chronobiological protocols, the present work aims to contribute towards these studies by exploring day-night variations of thermoregulatory functions in tuco-tucos, starting with body temperature and its temporal relationship to locomotor activity. Animals showed daily, 24 h body temperature rhythms that persisted even in constant darkness and temperature, synchronizing to a daily light/dark cycle, with highest values occurring during darkness hours. The range of oscillation of body temperature was slightly lower than those reported for similar-sized and dark-active rodents. Most rhythmic parameters, such as period and phase, did not change upon removal of the running wheel. Body temperature and locomotor activity rhythms were robustly associated in time. The former persisted even after removal of the acute effects of intense activity on body temperature by a statistical method. Finally, regression gradients between body temperature and activity were higher in the beginning of the night, suggesting day-night variation in thermal conductance and heat production. Consideration of these day-night variations in thermoregulatory processes is beneficial for further studies on thermoregulation and energetics of subterranean rodents.
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Affiliation(s)
- Patricia Tachinardi
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - José Eduardo Wilken Bicudo
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Gisele Akemi Oda
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Verónica Sandra Valentinuzzi
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR-CONICET). Entre Ríos y Mendoza s/n, Anillaco, La Rioja, Argentina
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