1
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Prakash A, Gower DJ, Vengot R, Kotharambath R. Circadian rhythm and surface activity in soil-dwelling caecilians (Amphibia: Gymnophiona). Sci Rep 2024; 14:9950. [PMID: 38688941 PMCID: PMC11061191 DOI: 10.1038/s41598-024-60533-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 04/23/2024] [Indexed: 05/02/2024] Open
Abstract
The degree to which burrowing, soil-dwelling caecilian amphibians spend time on the surface is little studied, and circadian rhythm has not been investigated in multiple species of this order or by manipulating light-dark cycles. We studied surface-activity rhythm of the Indian caecilians Ichthyophis cf. longicephalus and Uraeotyphlus cf. oxyurus (Ichthyophiidae) and Gegeneophis tejaswini (Grandisoniidae), under LD, DD and DL cycles. We examined daily surface activity and the role of light-dark cycles as a zeitgeber. All three species were strictly nocturnal and G. tejaswini displayed the least surface activity. Four out of thirteen individuals, two I. cf. longicephalus, one G. tejaswini and one U. cf. oxyurus, displayed a more or less distinct surface-activity rhythm in all three cycles, and for the nine other animals the activity patterns were not evident. An approximately 24 h free-run period was observed in the three species. When the light-dark cycle was inverted, surface activity in the three species shifted to the dark phase. The findings of this study suggest that caecilians have a weak circadian surface-activity rhythm, and that the absence of light can act as a prominent zeitgeber in these burrowing, limbless amphibians.
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Affiliation(s)
- Avanthika Prakash
- Department of Zoology, Central University of Kerala, Tejaswini Hills, Kasaragod, Kerala, India
| | - David J Gower
- Department of Zoology, Central University of Kerala, Tejaswini Hills, Kasaragod, Kerala, India
- Natural History Museum, London, SW7 5BD, UK
| | - Ranjith Vengot
- Department of Zoology, Central University of Kerala, Tejaswini Hills, Kasaragod, Kerala, India
| | - Ramachandran Kotharambath
- Department of Zoology, Central University of Kerala, Tejaswini Hills, Kasaragod, Kerala, India.
- Natural History Museum, London, SW7 5BD, UK.
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2
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Braunstein S, Bennett NC, Voigt C, Oosthuizen MK. Differential locomotor activity responses to day-time light intensity in juvenile and adult solitary Cape mole-rats, Georychus capensis (Rodentia: Bathyergidae). Chronobiol Int 2023; 40:1084-1096. [PMID: 37667495 DOI: 10.1080/07420528.2023.2253298] [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: 06/13/2023] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 09/06/2023]
Abstract
The Cape mole-rat (Georychus capensis) is a solitary, strictly subterranean rodent that is responsive to light and entrains to photic cues despite having a reduced visual system. Circadian entrainment is maintained throughout life, but age can alter the amplitude of the response and re-entrainment time. Mole-rats are long-lived for their size which raises questions regarding the robustness of their circadian rhythms and how impacts their locomotor activity rhythms. The locomotor activity rhythms of juvenile and adult Cape mole-rats were investigated. They were exposed to pre-experimental and post-experimental control cycles under fluorescent lights, six 12 h light:12 h dark cycles of decreasing intensities and a constant dark cycle (DD). All animals exhibited more activity during the dark phases of all light regimes. Juveniles were more active than adults and displayed more variable activity during both the light and dark phases. Adults exhibited relatively stable levels of activity under all experimental conditions, whereas juvenile activity decreased as the light intensity was reduced. The amplitude of Cape mole-rat rhythms was consistently low, but similar across light regimes and between adults and juveniles. Cape mole-rats have functional circadian systems, are primarily nocturnal and respond differentially to light intensity depending on their age. Light intensity does not affect the locomotor activity responses of Cape mole-rats in a predictable manner, and could indicate more complex interactions with light wavelengths. The circadian systems of juveniles appear to be more sensitive than those of adults, although the mechanism of the light response remains unclear.
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Affiliation(s)
- S Braunstein
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - N C Bennett
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - C Voigt
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - M K Oosthuizen
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
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3
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Oosthuizen MK, Bennett NC. Clocks Ticking in the Dark: A Review of Biological Rhythms in Subterranean African Mole-Rats. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.878533] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biological rhythms are rhythmic fluctuations of biological functions that occur in almost all organisms and on several time scales. These rhythms are generated endogenously and entail the coordination of physiological and behavioural processes to predictable, external environmental rhythms. The light-dark cycle is usually the most prominent environmental cue to which animals synchronise their rhythms. Biological rhythms are believed to provide an adaptive advantage to organisms. In the present review, we will examine the occurrence of circadian and seasonal rhythms in African mole-rats (family Bathyergidae). African mole-rats are strictly subterranean, they very rarely emerge aboveground and therefore, do not have regular access to environmental light. A key adaptation to their specialised habitat is a reduction in the visual system. Mole-rats exhibit both daily and seasonal rhythmicity in a range of behaviours and physiological variables, albeit to different degrees and with large variability. We review previous research on the entire circadian system of African mole-rats and discuss output rhythms in detail. Laboratory experiments imply that light remains the strongest zeitgeber for entrainment but in the absence of light, animals can entrain to ambient temperature rhythms. Field studies report that rhythmic daily and seasonal behaviour is displayed in their natural habitat. We suggest that ambient temperature and rainfall play an important role in the timing of rhythmic behaviour in mole-rats, and that they likely respond directly to these zeitgebers in the field rather than exhibit robust endogenous rhythms. In the light of climate change, these subterranean animals are buffered from the direct and immediate effects of changes in temperature and rainfall, partly because they do not have robust circadian rhythms, however, on a longer term they are vulnerable to changes in their food sources and dispersal abilities.
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4
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Zhang G, Chu Y, Jiang T, Li J, Feng L, Wu H, Wang H, Feng J. Comparative analysis of the daily brain transcriptomes of Asian particolored bat. Sci Rep 2022; 12:3876. [PMID: 35264653 PMCID: PMC8907190 DOI: 10.1038/s41598-022-07787-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/24/2022] [Indexed: 11/21/2022] Open
Abstract
Daily rhythms are found in almost all organisms, and they comprise one of the most basic characteristics of living things. Daily rhythms are generated and mainly regulated by circadian clock. Bats have attracted interest from researchers because of their unique biological characteristics. However, little is known about the molecular underpinnings of daily rhythms in bats. In this study, we used RNA-Seq to uncover the daily rhythms of gene expression in the brains of Asian particolored bats over the 24-h day. Accordingly, four collected time points corresponding to four biological states, rest, sleep, wakefulness, and active, were selected. Several groups of genes with different expression levels in these four states were obtained suggested that different physiological processes were active at various biological states, including drug metabolism, signaling pathways, and the circadian rhythm. Furthermore, downstream analysis of all differentially expressed genes in these four states suggested that groups of genes showed daily rhythms in the bat brain. Especially for Per1, an important circadian clock gene was identified with rhythmic expression in the brain of Asian particolored bat. In summary, our study provides an overview of the brain transcriptomic differences in different physiological states over a 24-h cycle.
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Affiliation(s)
- Guoting Zhang
- College of Life Science, Jilin Agricultural University, Changchun, 130118, China
| | - Yujia Chu
- College of Life Science, Jilin Agricultural University, Changchun, 130118, China
| | - Tinglei Jiang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130117, China
| | - Jingjing Li
- College of Life Science, Jilin Agricultural University, Changchun, 130118, China
| | - Lei Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130117, China
| | - Hui Wu
- College of Life Science, Jilin Agricultural University, Changchun, 130118, China
| | - Hui Wang
- College of Life Science, Jilin Agricultural University, Changchun, 130118, China.
| | - Jiang Feng
- College of Life Science, Jilin Agricultural University, Changchun, 130118, China. .,Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun, 130117, China.
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5
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Vice EN, Lagestee S, Browe BM, Deb D, Smith ESJ, Park TJ. Sensory Systems of the African Naked Mole-Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:137-156. [PMID: 34424515 DOI: 10.1007/978-3-030-65943-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Naked mole-rats share some sensory characteristics with other subterraneans, including lack of object vision, retention of the ability to entrain their circadian rhythm to light, and poor hearing. On the other hand, a characteristic that may be specialized in the naked mole-rat is their exquisite orienting responses to the touch of even a single body vibrissa. They have about 100 whisker-like body vibrissae on their otherwise furless bodies. They are also insensitive to chemical and inflammatory pain, likely an adaptation to living in an atmosphere that is high in carbon dioxide, a result of many respiring individuals driving carbon dioxide accumulation. Naked mole-rats have the highest population density among subterranean mammals. High levels of carbon dioxide cause tissue acidosis and associated pain. Remarkably, naked mole-rats are completely immune to carbon dioxide-induced pulmonary edema. However, they retain the ability to detect acid as a taste (sour). Finally, their ability to smell and discriminate odors is comparable to that of rats and mice, but their vomeronasal organ, associated with sensing pheromones, is extremely small and shows a complete lack of post-natal growth. In this chapter, we review what is known about the sensory systems of the naked mole-rat with emphasis on how they differ from other mammals, and even other subterraneans. More extensive accounts of the naked mole-rat's auditory and pain systems can be found in other chapters of this book.
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Affiliation(s)
- Emily N Vice
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Samantha Lagestee
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Brigitte M Browe
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Deblina Deb
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.,Kids In Motion Pediatric Therapy Services, Highland, MI, USA
| | - Ewan St J Smith
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Thomas J Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.
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Hart DW, van Jaarsveld B, Lasch KG, Grenfell KL, Oosthuizen MK, Bennett NC. Ambient Temperature as a Strong Zeitgeber of Circadian Rhythms in Response to Temperature Sensitivity and Poor Heat Dissipation Abilities in Subterranean African Mole-Rats. J Biol Rhythms 2021; 36:461-469. [PMID: 34343446 DOI: 10.1177/07487304211034287] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mammals have evolved circadian rhythms in internal biological processes and behaviors, such as locomotor activity (LA), to synchronize to the environmental conditions they experience. Photic entrainment of LA has been well established; however, non-photic entrainment, such as ambient temperature (Ta), has received much less attention. To address this dearth of knowledge, we exposed two subterranean endothermic-homeothermic African mole-rat species, the solitary Cape mole-rat (Georychus capensis [GC]) and social Mahali mole-rat (Cryptomys hottentotus mahali [CHM]), to varying Ta cycles in the absence of light. We showed that the LA rhythms of these two species entrain to Ta cycles and that the majority of LA occurred during the coolest 12-h period. LA confined to the coolest Ta periods may be the direct consequence of the poor heat dissipation abilities of African mole-rats brought about by physiological and ecological constraints. Recently, it has been hypothesized that Ta is only a strong zeitgeber for circadian rhythms in species whose thermoregulatory abilities are sensitive to changes in Ta (i.e., heterotherms and ectotherms), which previously has excluded endothermic-homeothermic mammals. However, this study demonstrates that Ta is a strong zeitgeber or entrainer for circadian rhythms of LA in subterranean endothermic-homeothermic mammals as a consequence of their sensitivity to changes in Ta brought about by their poor heat dissipation abilities. This study reinforces the intimate link between circadian rhythms and thermoregulation and conclusively, for the first time, provides evidence that Ta is a strong zeitgeber for endothermic-homeothermic mammals.
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Affiliation(s)
- Daniel W Hart
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Barry van Jaarsveld
- Department of Physical Geography, Utrecht University, Utrecht, The Netherlands
| | - Kiara G Lasch
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Kerryn L Grenfell
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Maria K Oosthuizen
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
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7
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Oosthuizen M, Robb G, Harrison A, Froneman A, Joubert K, Bennett N. Flexibility in body temperature rhythms of free-living natal mole-rats (Cryptomys hottentotus natalensis). J Therm Biol 2021; 99:102973. [DOI: 10.1016/j.jtherbio.2021.102973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 10/25/2022]
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8
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van Jaarsveld B, Bennett NC, Hart DW, Oosthuizen MK. Locomotor activity and body temperature rhythms in the Mahali mole-rat (C. h. mahali): The effect of light and ambient temperature variations. J Therm Biol 2019; 79:24-32. [DOI: 10.1016/j.jtherbio.2018.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 10/27/2022]
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9
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Abhilash L, Shindey R, Sharma VK. To be or not to be rhythmic? A review of studies on organisms inhabiting constant environments. BIOL RHYTHM RES 2017. [DOI: 10.1080/09291016.2017.1345426] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Lakshman Abhilash
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Radhika Shindey
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Vijay Kumar Sharma
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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10
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Haupt M, Bennett NC, Oosthuizen MK. Locomotor Activity and Body Temperature Patterns over a Temperature Gradient in the Highveld Mole-Rat (Cryptomys hottentotus pretoriae). PLoS One 2017; 12:e0169644. [PMID: 28072840 PMCID: PMC5224861 DOI: 10.1371/journal.pone.0169644] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 12/20/2016] [Indexed: 11/21/2022] Open
Abstract
African mole-rats are strictly subterranean mammals that live in extensive burrow systems. High humidity levels in the burrows prevent mole-rats from thermoregulating using evaporative cooling. However, the relatively stable environment of the burrows promotes moderate temperatures and small daily temperature fluctuations. Mole-rats therefore display a relatively wide range of thermoregulation abilities. Some species cannot maintain their body temperatures at a constant level, whereas others employ behavioural thermoregulation. Here we test the effect of ambient temperature on locomotor activity and body temperature, and the relationship between the two parameters, in the highveld mole-rat. We exposed mole-rats to a 12L:12D and a DD light cycle at ambient temperatures of 30°C, 25°C and 20°C while locomotor activity and body temperature were measured simultaneously. In addition, we investigated the endogenous rhythms of locomotor activity and body temperature at different ambient temperatures. Mole-rats displayed nocturnal activity at all three ambient temperatures and were most active at 20°C, but least active at 30°C. Body temperature was highest at 30°C and lowest at 20°C, and the daily cycle was highly correlated with locomotor activity. We show that the mole-rats have endogenous rhythms for both locomotor activity and body temperature. However, the endogenous body temperature rhythm appears to be less robust compared to the locomotor activity rhythm. Female mole-rats appear to be more sensitive to temperature changes than males, increased heterothermy is evident at lower ambient temperatures, whilst males show smaller variation in their body temperatures with changing ambient temperatures. Mole-rats may rely more heavily on behavioural thermoregulation as it is more energy efficient in an already challenging environment.
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Affiliation(s)
- Meghan Haupt
- Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Nigel C. Bennett
- Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Maria K. Oosthuizen
- Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
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11
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Ackermann S, Bennett NC, Katandukila JV, Oosthuizen MK. Circadian rhythms of locomotor activity in captive Emin’s mole-rats,Heliophobius emini(Rodentia: Bathyergidae). J Mammal 2016. [DOI: 10.1093/jmammal/gyw166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Kott O, Němec P, Fremlová A, Mazoch V, Šumbera R. Behavioural Tests Reveal Severe Visual Deficits in the Strictly Subterranean African Mole-Rats (Bathyergidae) but Efficient Vision in the Fossorial Rodent Coruro (Spalacopus cyanus, Octodontidae). Ethology 2016. [DOI: 10.1111/eth.12515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ondřej Kott
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Pavel Němec
- Department of Zoology; Faculty of Science; Charles University in Prague; Prague Czech Republic
| | - Aneta Fremlová
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Vladimír Mazoch
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Radim Šumbera
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
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Beale AD, Whitmore D, Moran D. Life in a dark biosphere: a review of circadian physiology in "arrhythmic" environments. J Comp Physiol B 2016; 186:947-968. [PMID: 27263116 PMCID: PMC5090016 DOI: 10.1007/s00360-016-1000-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/05/2016] [Accepted: 05/17/2016] [Indexed: 11/25/2022]
Abstract
Most of the life with which humans interact is exposed to highly rhythmic and extremely predictable changes in illumination that occur with the daily events of sunrise and sunset. However, while the influence of the sun feels omnipotent to surface dwellers such as ourselves, life on earth is dominated, in terms of biomass, by organisms isolated from the direct effects of the sun. A limited understanding of what life is like away from the sun can be inferred from our knowledge of physiology and ecology in the light biosphere, but a full understanding can only be gained by studying animals from the dark biosphere, both in the laboratory and in their natural habitats. One of the least understood aspects of life in the dark biosphere is the rhythmicity of physiology and what it means to live in an environment of low or no rhythmicity. Here we describe methods that may be used to understand rhythmic physiology in the dark and summarise some of the studies of rhythmic physiology in "arrhythmic" environments, such as the poles, deep sea and caves. We review what can be understood about the adaptive value of rhythmic physiology on the Earth's surface from studies of animals from arrhythmic environments and what role a circadian clock may play in the dark.
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Affiliation(s)
- Andrew David Beale
- Department of Cell and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, 21 University Street, London, WC1E 6BT, UK.
| | - David Whitmore
- Department of Cell and Developmental Biology, Centre for Cell and Molecular Dynamics, University College London, 21 University Street, London, WC1E 6BT, UK
| | - Damian Moran
- Plant and Food Research, Seafood Technologies Group, Nelson, New Zealand.
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Katandukila JV, Bennett NC, Chimimba CT, Faulkes CG, Oosthuizen MK. Locomotor activity patterns of captive East African root rats,Tachyoryctes splendens(Rodentia: Spalacidae), from Tanzania, East Africa. J Mammal 2013. [DOI: 10.1644/13-mamm-a-095.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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15
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Oosthuizen MK, Bennett NC, Cooper HM. PHOTIC INDUCTION OF Fos IN THE SUPRACHIASMATIC NUCLEUS OF AFRICAN MOLE-RATS: RESPONSES TO INCREASING IRRADIANCE. Chronobiol Int 2010; 27:1532-45. [DOI: 10.3109/07420528.2010.510227] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Maria K. Oosthuizen
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Nigel C. Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Howard M. Cooper
- Stem Cell and Brain Research Institute, Department of Chronobiology, INSERM, U846, Bron, France
- University of Lyon, Lyon I, Lyon, France
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16
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Kott O, Šumbera R, Němec P. Light perception in two strictly subterranean rodents: life in the dark or blue? PLoS One 2010; 5:e11810. [PMID: 20676369 PMCID: PMC2911378 DOI: 10.1371/journal.pone.0011810] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 06/23/2010] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The African mole-rats (Bathyergidae, Rodentia) are strictly subterranean, congenitally microphthalmic rodents that are hardly ever exposed to environmental light. Because of the lack of an overt behavioural reaction to light, they have long been considered to be blind. However, recent anatomical studies have suggested retention of basic visual capabilities. In this study, we employed behavioural tests to find out if two mole-rat species are able to discriminate between light and dark, if they are able to discriminate colours and, finally, if the presence of light in burrows provokes plugging behaviour, which is assumed to have a primarily anti-predatory function. METHODOLOGY/PRINCIPAL FINDING We used a binary choice test to show that the silvery mole-rat Heliophobius argenteocinereus and the giant mole-rat Fukomys mechowii exhibit a clear photoavoidance response to full-spectrum ("white"), blue and green-yellow light, but no significant reaction to ultraviolet or red light during nest building. The mole-rats thus retain dark/light discrimination capabilities and a capacity to perceive short to medium-wavelength light in the photopic range of intensities. These findings further suggest that the mole-rat S opsin has its absorption maximum in the violet/blue part of the spectrum. The assay did not yield conclusive evidence regarding colour discrimination. To test the putative role of vision in bathyergid anti-predatory behaviour, we examined the reaction of mole-rats to the incidence of light in an artificial burrow system. The presence of light in the burrow effectively induced plugging of the illuminated tunnel. CONCLUSION/SIGNIFICANCE Our findings suggest that the photopic vision is conserved and that low acuity residual vision plays an important role in predator avoidance and tunnel maintenance in the African mole-rats.
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Affiliation(s)
- Ondřej Kott
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
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de Vries JL, Oosthuizen MK, Sichilima AM, Bennett NC. Circadian rhythms of locomotor activity in Ansell's mole-rat: are mole-rat's clocks ticking? J Zool (1987) 2008. [DOI: 10.1111/j.1469-7998.2008.00496.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Nathaniel TI, Umesiri FE, Olajuyigbe F. Role of M1 receptor in the locomotion behavior of the African mole-rat (Cryptomys sp). J Integr Neurosci 2008; 7:1-16. [PMID: 18431815 DOI: 10.1142/s021963520800168x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 02/11/2008] [Indexed: 01/14/2023] Open
Abstract
Studies exploring the endogenous mechanism that modulates locomotion in Cryptomys sp, a bathyergid of the subterranean hystricomorph African mole-rat species might contribute to the understanding of the interrelations between external variables and internal mechanisms that controls the diverse patterns of locomotion in mole-rats. It has been shown that environmental variables contribute to the inter-individual variations in the daily patterns of locomotion, however, it is not well known if endogenous mechanism such as M1 receptor that regulates locomotion in surface dwelling rodents could as well regulate locomotion in the subterranean dwelling rodent. The present study explores this issue in Cryptomys sp a subterranean African mole-rat species. Using both specific and non-specific antagonists and agonists of M1 receptor, we manipulated the centrally expressed M1 receptor activity and characterized the effects of such manipulations on locomotor activity of Cryptomys sp. Our results indicate that infusion of M1 receptor specific and non-specific antagonists into the left or right ventricle impaired translatory movements, resulting in the display of abnormal complex rotatory locomotion. Based on the findings of this study, we suggest that M1 receptor activity might be part of the endogenous mechanisms that regulate the locomotor activity of Cryptomys sp.
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Affiliation(s)
- Thomas I Nathaniel
- Center for Natural and Health Sciences, Science Department, Marywood University, 2300 Adams Ave., Scranton, PA 18509, USA.
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Šklíba J, Šumbera R, Chitaukali WN, Burda H. Determinants of Daily Activity Patterns in a Free-Living Afrotropical Solitary Subterranean Rodent. J Mammal 2007. [DOI: 10.1644/06-mamm-a-235r1.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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