1
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Song Y, Zhang N, Yue Y, Chen D, Chou C, An L, Cheng L, Zhang J, Tian J. Field outcomes of laparoscopic ovum pick-up combined with in vitro embryo production in sheep: Effects of long-acting recombinant ovine FSH pre-stimulation, collection frequency, and donor breed. Domest Anim Endocrinol 2024; 87:106826. [PMID: 38043389 DOI: 10.1016/j.domaniend.2023.106826] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/07/2023] [Accepted: 11/17/2023] [Indexed: 12/05/2023]
Abstract
Laparoscopic ovum pick-up (LOPU) combined with in vitro embryo production (IVEP) is a technology platform that improves the utilization rate of the elite ewe's ovarian oocytes and increases the number of obtained offspring. This study aimed to evaluate the effects of FSH pre-stimulation, serial oocyte collection, and breed on LOPU-IVEP under field conditions. Donors were randomly assigned to five groups (group A: decreasing doses of pituitary FSH (p-FSH); group B: constant doses of p-FSH; group C: two doses of long-acting recombinant ovine FSH (ro-FSH); group D: single administration of a long-acting ro-FSH in; group E: no FSH stimulation). Oocyte yield following LOPU (average recovered oocytes: 20.9 ± 0.5; average viable oocytes: 17.2 ± 0.4) and oocyte developmental competence (average blastocysts: 7.0 ± 0.2) in group C were significantly better than these of group D and group E, and similar to these of groups A and B. Meanwhile, there were no differences in oocyte yield and developmental capacity using repeated LOPU session at 1-, 2-, and 3-month intervals (p > 0.05). Finally, we compared LOPU-IVEP outcomes among five sheep breeds. The results indicated that East Friesian × Chinese Mongolian crossbred sheep and purebred East Friesian sheep had the more recovered oocytes and viable oocytes compared with the Suffolk, Dorper, and Texel breeds, and average number of blastocysts in East Friesian × Chinese Mongolian sheep group was also highest among the groups (8.1 ±0.3, p < 0.05). In summary, the results of this study indicate long-acting ro-FSH pre-stimulation combined with 12 times LOPU sessions over one year maximizes embryo production of elite donor ewes under field conditions.
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Affiliation(s)
- Yukun Song
- Inner Mongolia Key Laboratory of Sheep & Goat Genetics Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China
| | - Nan Zhang
- Inner Mongolia Key Laboratory of Sheep & Goat Genetics Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China
| | - Yuan Yue
- College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Dayong Chen
- Inner Mongolia Sino Sheep Technology Co. Ltd., Ulanqab, Inner Mongolia 011800, China
| | - Chunjuan Chou
- Inner Mongolia Sino Sheep Technology Co. Ltd., Ulanqab, Inner Mongolia 011800, China
| | - Lei An
- College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Lei Cheng
- Xilingol Vocational College, Xilinhot, Inner Mongolia 026000, China
| | - Jiaxin Zhang
- Inner Mongolia Key Laboratory of Sheep & Goat Genetics Breeding and Reproduction, College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
| | - Jianhui Tian
- College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
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2
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van Rosmalen L, Riedstra B, Beemster N, Dijkstra C, Hut RA. Differential temperature effects on photoperiodism in female voles: A possible explanation for declines in vole populations. Mol Ecol 2022; 31:3360-3373. [PMID: 35398940 PMCID: PMC9325516 DOI: 10.1111/mec.16467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 03/20/2022] [Accepted: 03/28/2022] [Indexed: 11/30/2022]
Abstract
Many mammalian species use photoperiod as a predictive cue to time seasonal reproduction. In addition, metabolic effects on the reproductive axis may also influence seasonal timing, especially in female small, short-lived mammals. To get a better understanding of how annual cycling environmental cues impact reproductive function and plasticity in small, short-lived herbivores with different geographic origins, we investigated the mechanisms underlying integration of temperature in the photoperiodic-axis regulating female reproduction in a Northern vole species (tundra vole, Microtus oeconomus) and in a Southern vole species (common vole, Microtus arvalis). We show that photoperiod and temperature interact to determine appropriate physiological responses; there is species-dependent annual variation in the sensitivity to temperature for reproductive organ development. In common voles, temperature can overrule photoperiodical spring-programmed responses, with reproductive organ mass being higher at 10°C than at 21°C, whereas in autumn they are less sensitive to temperature. These findings are in line with our census data, showing an earlier onset of spring reproduction in cold springs, while reproductive offset in autumn is synchronized to photoperiod. The reproductive organs of tundra voles were relatively insensitive to temperature, whereas hypothalamic gene expression was generally upregulated at 10°C. Thus, both vole species use photoperiod, whereas only common voles use temperature as a cue to control spring reproduction, which indicates species-specific reproductive strategies. Due to global warming, spring reproduction in common voles will be delayed, perhaps resulting in shorter breeding seasons and thus declining populations, as observed throughout Europe.
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Affiliation(s)
- Laura van Rosmalen
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
- Present address:
Salk Institute for Biological StudiesLa JollaCaliforniaUSA
| | - Bernd Riedstra
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Nico Beemster
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
- Present address:
Altenburg & Wymenga Ecological ConsultantsFeanwâldenThe Netherlands
| | - Cor Dijkstra
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Roelof A. Hut
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
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3
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Liu JA, Meléndez-Fernández OH, Bumgarner JR, Nelson RJ. Effects of light pollution on photoperiod-driven seasonality. Horm Behav 2022; 141:105150. [PMID: 35304351 PMCID: PMC10137835 DOI: 10.1016/j.yhbeh.2022.105150] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 12/23/2022]
Abstract
Changes to photoperiod (day length) occur in anticipation of seasonal environmental changes, altering physiology and behavior to maximize fitness. In order for photoperiod to be useful as a predictive factor of temperature or food availability, day and night must be distinct. The increasing prevalence of exposure to artificial light at night (ALAN) in both field and laboratory settings disrupts photoperiodic time measurement and may block development of appropriate seasonal adaptations. Here, we review the effects of ALAN as a disruptor of photoperiodic time measurement and season-specific adaptations, including reproduction, metabolism, immune function, and thermoregulation.
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Affiliation(s)
- Jennifer A Liu
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, West Virginia, USA.
| | | | - Jacob R Bumgarner
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, West Virginia, USA
| | - Randy J Nelson
- Department of Neuroscience, Rockefeller Neuroscience Institute, West Virginia University, West Virginia, USA
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4
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van Rosmalen L, Hut RA. Food and temperature change photoperiodic responses in two vole species. J Exp Biol 2021; 224:273462. [PMID: 34787302 DOI: 10.1242/jeb.243030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/10/2021] [Indexed: 01/23/2023]
Abstract
Seasonal timing of reproduction in voles is driven by photoperiod. We hypothesized that a negative energy balance can modify spring-programmed photoperiodic responses in the hypothalamus, controlling reproductive organ development. We manipulated energy balance by the 'work-for-food' protocol, in which voles were exposed to increasing levels of food scarcity at different ambient temperatures under long photoperiod. We found that in common voles (Microtus arvalis) and tundra voles (Microtus oeconomus), photoperiod-induced pars tuberalis thyroid-stimulating hormone β-subunit (Tshβ) expression is reduced to potentially inhibit gonadal development when food is scarce. Reduction in gonadal size is more pronounced in tundra voles, in which anterior hypothalamic Kiss1 is additionally downregulated, especially in males. Low temperature additionally leads to decreased hypothalamic Rfrp expression, which potentially may facilitate further suppression of gonadal growth. Shutting off the photoperiodic axis when food is scarce in spring may be an adaptive response to save energy, leading to delayed reproductive organ development until food resources are sufficient for reproduction, lactation and offspring survival. Defining the mechanisms through which metabolic cues modify photoperiodic responses will be important for a better understanding of how environmental cues impact reproduction.
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Affiliation(s)
- Laura van Rosmalen
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Roelof A Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
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5
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Khodasevich D, Tsui S, Keung D, Skene DJ, Revell V, Martinez ME. Characterizing the modern light environment and its influence on circadian rhythms. Proc Biol Sci 2021; 288:20210721. [PMID: 34284625 PMCID: PMC8292753 DOI: 10.1098/rspb.2021.0721] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022] Open
Abstract
Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, we measured light exposure and wrist temperature among residents of an urban area during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, across all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference occurring between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modelled the impact of morning and night-time light exposure on the timing of the maximum wrist temperature. We found that morning and night-time light exposure had significant but opposing impacts on maximum wrist temperature timing. Our results demonstrate that, within the range of exposure seen in everyday life, night-time light can delay the onset of the maximum wrist temperature, while morning light can lead to earlier onset. Our results demonstrate that humans are minimizing natural seasonal differences in light exposure, and that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized.
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Affiliation(s)
- Dennis Khodasevich
- Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Susan Tsui
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Darwin Keung
- Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Debra J. Skene
- Chronobiology, University of Surrey, Guildford, Surrey, UK
| | - Victoria Revell
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
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6
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van Rosmalen L, van Dalum J, Appenroth D, Roodenrijs RTM, de Wit L, Hazlerigg DG, Hut RA. Mechanisms of temperature modulation in mammalian seasonal timing. FASEB J 2021; 35:e21605. [PMID: 33913553 DOI: 10.1096/fj.202100162r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 04/02/2021] [Indexed: 12/15/2022]
Abstract
Global warming is predicted to have major effects on the annual time windows during which species may successfully reproduce. At the organismal level, climatic shifts engage with the control mechanism for reproductive seasonality. In mammals, laboratory studies on neuroendocrine mechanism emphasize photoperiod as a predictive cue, but this is based on a restricted group of species. In contrast, field-oriented comparative analyses demonstrate that proximate bioenergetic effects on the reproductive axis are a major determinant of seasonal reproductive timing. The interaction between proximate energetic and predictive photoperiodic cues is neglected. Here, we focused on photoperiodic modulation of postnatal reproductive development in common voles (Microtus arvalis), a herbivorous species in which a plastic timing of breeding is well documented. We demonstrate that temperature-dependent modulation of photoperiodic responses manifest in the thyrotrophin-sensitive tanycytes of the mediobasal hypothalamus. Here, the photoperiod-dependent expression of type 2 deiodinase expression, associated with the summer phenotype was enhanced by 21°C, whereas the photoperiod-dependent expression of type 3 deiodinase expression, associated with the winter phenotype, was enhanced by 10°C in spring voles. Increased levels of testosterone were found at 21°C, whereas somatic and gonadal growth were oppositely affected by temperature. The magnitude of these temperature effects was similar in voles photoperiodical programmed for accelerated maturation (ie, born early in the breeding season) and in voles photoperiodical programmed for delayed maturation (ie, born late in the breeding season). The melatonin-sensitive pars tuberalis was relatively insensitive to temperature. These data define a mechanistic hierarchy for the integration of predictive temporal cues and proximate thermo-energetic effects in mammalian reproduction.
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Affiliation(s)
- Laura van Rosmalen
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Jayme van Dalum
- Arctic Seasonal Timekeeping initiative (ASTI), Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Daniel Appenroth
- Arctic Seasonal Timekeeping initiative (ASTI), Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Renzo T M Roodenrijs
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Lauren de Wit
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - David G Hazlerigg
- Arctic Seasonal Timekeeping initiative (ASTI), Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Roelof A Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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7
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Przybylska-Piech AS, Wojciechowski MS, Jefimow M. Polymorphism of winter phenotype in Siberian hamster: consecutive litters do not differ in photoresponsiveness but prolonged acclimation to long photoperiod inhibits winter molt. Front Zool 2021; 18:11. [PMID: 33731152 PMCID: PMC7971963 DOI: 10.1186/s12983-021-00391-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/21/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The theory of delayed life history effects assumes that phenotype of adult individual results from environmental conditions experienced at birth and as juvenile. In seasonal environments, being born late in the reproductive season affects timing of puberty, body condition, longevity, and fitness. We hypothesized that late-born individuals are more prone to respond to short photoperiod (SP) than early born ones. We used Siberian hamsters Phodopus sungorus, a model species characterized by high polymorphism of winter phenotype. We experimentally distinguished the effect of litter order (first or third) from the effect of exposure to long photoperiod (LP) before winter (3 months or 5 months) by manipulating the duration of LP acclimation in both litters. We predicted that, irrespective of the litter order, individuals exposed to long photoperiod for a short time have less time to gather energy resources and consequently are more prone to developing energy-conserving phenotypes. To assess effect of litter order, duration of acclimation to long days, and phenotype on basal cost of living we measured basal metabolic rate (BMR) of hamsters. RESULTS Individuals born in third litters had faster growth rates and were bigger than individuals from first litters, but these differences vanished before transfer to SP. Litter order or duration of LP acclimation had no effects on torpor use or seasonal body mass changes, but prolonged acclimation to LP inhibited winter molting both in first and third litters. Moreover, individuals that did not molt had significantly higher BMR in SP than those which molted to white fur. Although one phenotype usually predominated within a litter, littermates were often heterogeneous. We also found that over 10% of individuals presented late response to short photoperiod. CONCLUSIONS Our data indicate that duration of postnatal exposure to LP may define propensity to photoresponsiveness, regardless of the litter in which animal was born. Existence of littermates presenting different phenotypes suggests a prudent reproductive strategy of investing into offspring of varied phenotypes, that might be favored depending on environmental conditions. This strategy could have evolved in response to living in stochastic environment.
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Affiliation(s)
- Anna S Przybylska-Piech
- Department of Vertebrate Zoology and Ecology, Nicolaus Copernicus University, Toruń, Poland.
| | - Michał S Wojciechowski
- Department of Vertebrate Zoology and Ecology, Nicolaus Copernicus University, Toruń, Poland
| | - Małgorzata Jefimow
- Department of Animal Physiology and Neurobiology, Nicolaus Copernicus University, Toruń, Poland
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8
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Dardente H, Migaud M. Thyroid hormone and hypothalamic stem cells in seasonal functions. VITAMINS AND HORMONES 2021; 116:91-131. [PMID: 33752829 DOI: 10.1016/bs.vh.2021.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Seasonal rhythms are a pervasive feature of most living organisms, which underlie yearly timeliness in breeding, migration, hibernation or weight gain and loss. To achieve this, organisms have developed inner timing devices (circannual clocks) that endow them with the ability to predict then anticipate changes to come, usually using daylength as the proximate cue. In Vertebrates, daylength interpretation involves photoperiodic control of TSH production by the pars tuberalis (PT) of the pituitary, which governs a seasonal switch in thyroid hormone (TH) availability in the neighboring hypothalamus. Tanycytes, specialized glial cells lining the third ventricle (3V), are responsible for this TH output through the opposite, PT-TSH-driven, seasonal control of deiodinases 2/3 (Dio 2/3). Tanycytes comprise a photoperiod-sensitive stem cell niche and TH is known to play major roles in cell proliferation and differentiation, which suggests that seasonal control of tanycyte proliferation may be involved in the photoperiodic synchronization of seasonal rhythms. Here we review our current knowledge of the molecular and neuroendocrine pathway linking photoperiodic information to seasonal changes in physiological functions and discuss the potential implication of tanycytes, TH and cell proliferation in seasonal timing.
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Affiliation(s)
- Hugues Dardente
- PRC, INRAE, CNRS, IFCE, Université de Tours, Nouzilly, France.
| | - Martine Migaud
- PRC, INRAE, CNRS, IFCE, Université de Tours, Nouzilly, France
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9
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Wilsterman K, Ballinger MA, Williams CM. A unifying, eco‐physiological framework for animal dormancy. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13718] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Kathryn Wilsterman
- Biological Sciences University of Montana Missoula MT USA
- Integrative Biology University of California Berkeley CA USA
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10
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Williams RC, Blanco MB, Poelstra JW, Hunnicutt KE, Comeault AA, Yoder AD. Conservation genomic analysis reveals ancient introgression and declining levels of genetic diversity in Madagascar's hibernating dwarf lemurs. Heredity (Edinb) 2020; 124:236-251. [PMID: 31435007 PMCID: PMC6906314 DOI: 10.1038/s41437-019-0260-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 12/16/2022] Open
Abstract
Madagascar's biodiversity is notoriously threatened by deforestation and climate change. Many of these organisms are rare, cryptic, and severely threatened, making population-level sampling unrealistic. Such is the case with Madagascar's dwarf lemurs (genus Cheirogaleus), the only obligate hibernating primate. We here apply comparative genomic approaches to generate the first genome-wide estimates of genetic diversity within dwarf lemurs. We generate a reference genome for the fat-tailed dwarf lemur, Cheirogaleus medius, and use this resource to facilitate analyses of high-coverage (~30×) genome sequences for wild-caught individuals representing species: C. sp. cf. medius, C. major, C. crossleyi, and C. sibreei. This study represents the largest contribution to date of novel genomic resources for Madagascar's lemurs. We find concordant phylogenetic relationships among the four lineages of Cheirogaleus across most of the genome, and yet detect a number of discordant genomic regions consistent with ancient admixture. We hypothesized that these regions could have resulted from adaptive introgression related to hibernation, indeed finding that genes associated with hibernation are present, though most significantly, that gene ontology categories relating to transcription are over-represented. We estimate levels of heterozygosity and find particularly low levels in an individual sampled from an isolated population of C. medius that we refer to as C. sp. cf. medius. Results are consistent with a recent decline in effective population size, which is evident across species. Our study highlights the power of comparative genomic analysis for identifying species and populations of conservation concern, as well as for illuminating possible mechanisms of adaptive phenotypic evolution.
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Affiliation(s)
- Rachel C Williams
- Department of Biology, Duke University, Durham, NC, 27708, USA.
- Duke Lemur Center, Duke University, Durham, NC, 27705, USA.
| | - Marina B Blanco
- Department of Biology, Duke University, Durham, NC, 27708, USA
- Duke Lemur Center, Duke University, Durham, NC, 27705, USA
| | | | - Kelsie E Hunnicutt
- Department of Biological Sciences, University of Denver, Denver, CO, 80208, USA
| | - Aaron A Comeault
- Biology Department, University of North Carolina, Chapel Hill, NC, 27599, USA
- School of Natural Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC, 27708, USA
- Duke Lemur Center, Duke University, Durham, NC, 27705, USA
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11
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Regan JC, Froy H, Walling CA, Moatt JP, Nussey DH. Dietary restriction and insulin‐like signalling pathways as adaptive plasticity: A synthesis and re‐evaluation. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13418] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Jennifer C. Regan
- Institute of Immunology and Infection Research, School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Hannah Froy
- Centre for Biodiversity Dynamics Norwegian University of Science and Technology Trondheim Norway
| | - Craig A. Walling
- Institute for Evolutionary Biology, School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Joshua P. Moatt
- Institute for Evolutionary Biology, School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Daniel H. Nussey
- Institute of Immunology and Infection Research, School of Biological Sciences University of Edinburgh Edinburgh UK
- Institute for Evolutionary Biology, School of Biological Sciences University of Edinburgh Edinburgh UK
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12
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Wang D, Li N, Tian L, Ren F, Li Z, Chen Y, Liu L, Hu X, Zhang X, Song Y, Hut RA, Liu XH. Dynamic expressions of hypothalamic genes regulate seasonal breeding in a natural rodent population. Mol Ecol 2019; 28:3508-3522. [PMID: 31233652 DOI: 10.1111/mec.15161] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 05/22/2019] [Accepted: 06/04/2019] [Indexed: 12/31/2022]
Abstract
Seasonal breeding is a universal reproductive strategy in many animals. Hypothalamic genes, especially type 2 and 3 iodothyronine deiodinases (Dio2/3), RFamide-related peptide 3 (Rfrp-3), kisspeptin (Kiss-1) and gonadotropin-releasing hormone (GnRH), are involved in a photoperiodic pathway that encodes seasonal signals from day length in many vertebrate species. However, the seasonal expression patterns of these genes in wild mammals are less studied. Here, we present a four-year field investigation to reveal seasonal rhythm and age-dependent reproductive activity in male Brandt's voles (Lasiopodomys brandtii) and to detect relationships among seasonal expression profiles of hypothalamic genes, testicular activity, age and annual day length. From breeding season (April) to nonbreeding season (October), adult male voles displayed a synchronous peak in gonadal activity with annual day length around summer solstice, which was jointly caused by age structure shifts and age-dependent gonadal development patterns. Overwintered males maintained reproductive activity until late in the breeding season, whereas most newborn males terminated gonadal development completely, except for a minority of males born early in spring. Consistently, the synchronous and opposite expression profiles of Dio2/3 suggest their central function to decode photoperiodic signals and to predict the onset of the nonbreeding season. Moreover, changes in Dio2/3 signals may guide the actions of Kiss-1 and Rfrp-3 to regulate the age-dependent divergence of reproductive strategy in wild Brandt's vole. Our results provide evidence on how hypothalamic photoperiod genes regulate seasonal breeding in a natural rodent population.
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Affiliation(s)
- Dawei Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ning Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lin Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fei Ren
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhengguang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yan Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.,College of Life Sciences, Sichuan University, Chengdu, China
| | - Lan Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.,College of Life Sciences, Sichuan University, Chengdu, China
| | - Xiangfa Hu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xuechang Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ying Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Roelof A Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Xiao-Hui Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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13
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Santi D, Spaggiari G, Brigante G, Setti M, Tagliavini S, Trenti T, Simoni M. Semi-annual seasonal pattern of serum thyrotropin in adults. Sci Rep 2019; 9:10786. [PMID: 31346248 PMCID: PMC6658473 DOI: 10.1038/s41598-019-47349-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/16/2019] [Indexed: 12/19/2022] Open
Abstract
Circannual rhythmicity in thyroid-stimulating hormone (TSH) secretion is proposed, whereas evidences on seasonal peripheral thyroid hormones’ fluctuation are contradictory. This study was designed to evaluate hypothalamic-pituitary-thyroid (HPT) seasonal secretion pattern using a big data approach. An observational, retrospective, big data trial was carried out, including all TSH measurements performed in a single laboratory between January 2010 and December 2017. A large dataset was created matching TSH data with patients’ age, gender, environmental temperature exposure, and free triiodothyronine (fT3) and free thyroxine (fT4) when available. The trend and seasonal distributions were analysed using autoregressive integrated moving average models. A total of 1,506,495 data were included in the final database with patients mean age of 59.00 ± 18.44 years. The mean TSH serum levels were 2.08 ± 1.57 microIU/mL, showing a seasonal distribution with higher levels in summer and winter seasons, independently from age, gender and environmental temperatures. Neither fT3 nor fT4 showed a seasonal trend. TSH seasonal changes occurred independently from peripheral thyroid hormone variations, gender, age and environmental temperatures. Although seasonal TSH fluctuation could represent a residual ancestral mechanism to maintain HPT homeostasis, the underlying physiological mechanism remains unclear and specific studies are needed to clarify its impacting role in humans.
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Affiliation(s)
- Daniele Santi
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy. .,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria of Modena, OCSAE, Modena, Italy.
| | - Giorgia Spaggiari
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria of Modena, OCSAE, Modena, Italy
| | - Giulia Brigante
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria of Modena, OCSAE, Modena, Italy
| | - Monica Setti
- Service of Clinical Engineering, Azienda Ospedaliero-Universitaria of Modena, Modena, Italy
| | - Simonetta Tagliavini
- Department of Laboratory Medicine and Anatomy Pathology, Azienda USL of Modena, Modena, Italy
| | - Tommaso Trenti
- Department of Laboratory Medicine and Anatomy Pathology, Azienda USL of Modena, Modena, Italy
| | - Manuela Simoni
- Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria of Modena, OCSAE, Modena, Italy
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14
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Integration of color and intensity increases time signal stability for the human circadian system when sunlight is obscured by clouds. Sci Rep 2018; 8:15214. [PMID: 30315193 PMCID: PMC6185968 DOI: 10.1038/s41598-018-33606-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/02/2018] [Indexed: 01/25/2023] Open
Abstract
The mammalian circadian system encodes both absolute levels of light intensity and color to phase-lock (entrain) its rhythm to the 24-h solar cycle. The evolutionary benefits of circadian color-coding over intensity-coding per se are yet far from understood. A detailed characterization of sunlight is crucial in understanding how and why circadian photoreception integrates color and intensity information. To this end, we continuously measured 100 days of sunlight spectra over the course of a year. Our analyses suggest that circadian color-coding may have evolved to cope with cloud-induced variation in light intensity. We proceed to show how an integration of intensity and spectral composition reduces day-to-day variability in the synchronizing signal (Zeitgeber). As a consequence, entrained phase angle of the circadian clock will be more stable, which will be beneficial for the organism. The presented characterization of sunlight dynamics may become important in designing lighting solutions aimed at minimizing the detrimental effects of light at night in modern societies.
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15
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van der Veen DR, Riede SJ, Heideman PD, Hau M, van der Vinne V, Hut RA. Flexible clock systems: adjusting the temporal programme. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0254. [PMID: 28993498 DOI: 10.1098/rstb.2016.0254] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2017] [Indexed: 12/20/2022] Open
Abstract
Under natural conditions, many aspects of the abiotic and biotic environment vary with time of day, season or even era, while these conditions are typically kept constant in laboratory settings. The timing information contained within the environment serves as critical timing cues for the internal biological timing system, but how this system drives daily rhythms in behaviour and physiology may also depend on the internal state of the animal. The disparity between timing of these cues in natural and laboratory conditions can result in substantial differences in the scheduling of behaviour and physiology under these conditions. In nature, temporal coordination of biological processes is critical to maximize fitness because they optimize the balance between reproduction, foraging and predation risk. Here we focus on the role of peripheral circadian clocks, and the rhythms that they drive, in enabling adaptive phenotypes. We discuss how reproduction, endocrine activity and metabolism interact with peripheral clocks, and outline the complex phenotypes arising from changes in this system. We conclude that peripheral timing is critical to adaptive plasticity of circadian organization in the field, and that we must abandon standard laboratory conditions to understand the mechanisms that underlie this plasticity which maximizes fitness under natural conditions.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'.
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Affiliation(s)
- Daan R van der Veen
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Sjaak J Riede
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Paul D Heideman
- Department of Biology, College of William and Mary, Williamsburg, VA, USA
| | - Michaela Hau
- Max-Planck-Institute for Ornithology, Seewiesen, Germany and University of Konstanz, Konstanz, Germany
| | - Vincent van der Vinne
- Neurobiology Department, University of Massachusetts Medical School, Worcester, MA, USA
| | - Roelof A Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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16
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Kronfeld-Schor N, Visser ME, Salis L, van Gils JA. Chronobiology of interspecific interactions in a changing world. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0248. [PMID: 28993492 DOI: 10.1098/rstb.2016.0248] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2017] [Indexed: 01/10/2023] Open
Abstract
Animals should time activities, such as foraging, migration and reproduction, as well as seasonal physiological adaptation, in a way that maximizes fitness. The fitness outcome of such activities depends largely on their interspecific interactions; the temporal overlap with other species determines when they should be active in order to maximize their encounters with food and to minimize their encounters with predators, competitors and parasites. To cope with the constantly changing, but predictable structure of the environment, organisms have evolved internal biological clocks, which are synchronized mainly by light, the most predictable and reliable environmental cue (but which can be masked by other variables), which enable them to anticipate and prepare for predicted changes in the timing of the species they interact with, on top of responding to them directly. Here, we review examples where the internal timing system is used to predict interspecific interactions, and how these interactions affect the internal timing system and activity patterns. We then ask how plastic these mechanisms are, how this plasticity differs between and within species and how this variability in plasticity affects interspecific interactions in a changing world, in which light, the major synchronizer of the biological clock, is no longer a reliable cue owing to the rapidly changing climate, the use of artificial light and urbanization.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'.
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Affiliation(s)
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO 50, Wageningen 6700 AB, The Netherlands
| | - Lucia Salis
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO 50, Wageningen 6700 AB, The Netherlands
| | - Jan A van Gils
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University, PO Box 59, Den Burg 1790 AB, The Netherlands
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17
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Hau M, Dominoni D, Casagrande S, Buck CL, Wagner G, Hazlerigg D, Greives T, Hut RA. Timing as a sexually selected trait: the right mate at the right moment. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0249. [PMID: 28993493 DOI: 10.1098/rstb.2016.0249] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2017] [Indexed: 12/20/2022] Open
Abstract
Sexual selection favours the expression of traits in one sex that attract members of the opposite sex for mating. The nature of sexually selected traits such as vocalization, colour and ornamentation, their fitness benefits as well as their costs have received ample attention in field and laboratory studies. However, sexually selected traits may not always be expressed: coloration and ornaments often follow a seasonal pattern and behaviours may be displayed only at specific times of the day. Despite the widely recognized differences in the daily and seasonal timing of traits and their consequences for reproductive success, the actions of sexual selection on the temporal organization of traits has received only scant attention. Drawing on selected examples from bird and mammal studies, here we summarize the current evidence for the daily and seasonal timing of traits. We highlight that molecular advances in chronobiology have opened exciting new opportunities for identifying the genetic targets that sexual selection may act on to shape the timing of trait expression. Furthermore, known genetic links between daily and seasonal timing mechanisms lead to the hypothesis that selection on one timescale may simultaneously also affect the other. We emphasize that studies on the timing of sexual displays of both males and females from wild populations will be invaluable for understanding the nature of sexual selection and its potential to act on differences within and between the sexes in timing. Molecular approaches will be important for pinpointing genetic components of biological rhythms that are targeted by sexual selection, and to clarify whether these represent core or peripheral components of endogenous clocks. Finally, we call for a renewed integration of the fields of evolution, behavioural ecology and chronobiology to tackle the exciting question of how sexual selection contributes to the evolution of biological clocks.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'.
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Affiliation(s)
- Michaela Hau
- Max Planck Institute for Ornithology, Seewiesen, Germany .,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Davide Dominoni
- Department of Animal Ecology, Netherlands Institute of Ecology, Wageningen, The Netherlands.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | | | - C Loren Buck
- Department of Biological Sciences and Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Gabriela Wagner
- Department of Arctic and Marine Biology, UiT: the Arctic University of Norway, Tromsø, Norway
| | - David Hazlerigg
- Department of Arctic and Marine Biology, UiT: the Arctic University of Norway, Tromsø, Norway
| | - Timothy Greives
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Roelof A Hut
- Chronobiology unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, The Netherlands
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18
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Williams CT, Klaassen M, Barnes BM, Buck CL, Arnold W, Giroud S, Vetter SG, Ruf T. Seasonal reproductive tactics: annual timing and the capital-to-income breeder continuum. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0250. [PMID: 28993494 DOI: 10.1098/rstb.2016.0250] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2017] [Indexed: 12/11/2022] Open
Abstract
Tactics of resource use for reproduction are an important feature of life-history strategies. A distinction is made between 'capital' breeders, which finance reproduction using stored energy, and 'income' breeders, which pay for reproduction using concurrent energy intake. In reality, vertebrates use a continuum of capital-to-income tactics, and, for many species, the allocation of capital towards reproduction is a plastic trait. Here, we review how trophic interactions and the timing of life-history events are influenced by tactics of resource use in birds and mammals. We first examine how plasticity in the allocation of capital towards reproduction is linked to phenological flexibility via interactions between endocrine/neuroendocrine control systems and the sensory circuits that detect changes in endogenous state, and environmental cues. We then describe the ecological drivers of reproductive timing in species that vary in the degree to which they finance reproduction using capital. Capital can be used either as a mechanism to facilitate temporal synchrony between energy supply and demand or as a means of lessening the need for synchrony. Within many species, an individual's ability to cope with environmental change may be more tightly linked to plasticity in resource allocation than to absolute position on the capital-to-income breeder continuum.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'.
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Affiliation(s)
- Cory T Williams
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Marcel Klaassen
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, 75 Pigdons Road, Geelong, Victoria 3216, Australia
| | - Brian M Barnes
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - C Loren Buck
- Center for Bioengineering Innovation & Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Walter Arnold
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, 1160 Vienna, Austria
| | - Sylvain Giroud
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, 1160 Vienna, Austria
| | - Sebastian G Vetter
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, 1160 Vienna, Austria
| | - Thomas Ruf
- Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, 1160 Vienna, Austria
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19
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Myung J, Pauls SD. Encoding seasonal information in a two-oscillator model of the multi-oscillator circadian clock. Eur J Neurosci 2017; 48:2718-2727. [PMID: 28921823 DOI: 10.1111/ejn.13697] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/01/2017] [Accepted: 09/11/2017] [Indexed: 02/01/2023]
Abstract
The suprachiasmatic nucleus (SCN) is a collection of about 10 000 neurons, each of which functions as a circadian clock with slightly different periods and phases, that work in concert with form and maintain the master circadian clock for the organism. The diversity among neurons confers on the SCN the ability to robustly encode both the 24-h light pattern as well as the seasonal time. Cluster synchronization brings the different neurons into line and reduces the large population to essentially two oscillators, coordinated by a macroscopic network motif of asymmetric repulsive-attractive coupling. We recount the steps leading to this simplification and rigorously examine the two-oscillator case by seeking an analytical solution. Through these steps, we identify physiologically relevant parameters that shape the behaviour of the SCN network and delineate its ability to store past details of seasonal variation in photoperiod.
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Affiliation(s)
- Jihwan Myung
- Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Lab 2 Level B, 1919-1 Tancha Onna-son, Kunigami, Okinawa 904-0495, Japan.,Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan.,TMU-Research Center of Brain and Consciousness, Shuang Ho Hospital, New Taipei City, Taiwan
| | - Scott D Pauls
- Department of Mathematics, Dartmouth College, 6188 Kemeny Hall, Hanover, NH 03755, USA
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20
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Seasonal loss and resumption of circadian rhythms in hibernating arctic ground squirrels. J Comp Physiol B 2017; 187:693-703. [PMID: 28332018 DOI: 10.1007/s00360-017-1069-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/04/2017] [Accepted: 02/26/2017] [Indexed: 12/28/2022]
Abstract
Circadian clocks are near universal among organisms and play a key role in coordinating physiological and metabolic functions to anticipate or coincide with predictable daily changes in the physical and social environment. However, whether circadian rhythms persist and are functionally important during hibernation in all mammals is currently unclear. We examined whether circadian rhythms of body temperature (T b) persist during multi-day, steady-state torpor and investigated the association between timing of animal emergence, exposure to light, and resumption of activity and T b rhythms in free-living and captive male arctic ground squirrels. High-resolution (0.02 °C) temperature loggers revealed that circadian rhythms of T b were not present during deep torpor in free-living arctic ground squirrels. Significant circadian rhythms of T b resumed, however, following the resumption of euthermia, but prior to emergence, though rhythms became much more robust coincident with aboveground emergence. Additionally, squirrels maintained in captivity under conditions of constant darkness spontaneously developed significant circadian rhythms of T b and activity soon after ending torpor. Exposing animals to a 5-s pulse of light within a week when they ended torpor increased the strength of rhythms. Our results are consistent with the hypothesis that circadian clock function is inhibited during hibernation in arctic ground squirrels, and we postulate that exposure to external stimuli, such as light in free-living animals, and meals or acute disturbance for captive squirrels, may enhance T b rhythmicity by synchronizing loosely coupled circadian oscillators within the suprachiasmatic nucleus.
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21
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Tsukamoto D, Ito M, Takamatsu N. HNF-4 participates in the hibernation-associated transcriptional regulation of the chipmunk hibernation-related protein gene. Sci Rep 2017; 7:44279. [PMID: 28281641 PMCID: PMC5345028 DOI: 10.1038/srep44279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 02/06/2017] [Indexed: 11/17/2022] Open
Abstract
The chipmunk hibernation-related protein 25 (HP-25) is involved in the circannual control of hibernation in the brain. The liver-specific expression of the HP-25 gene is repressed in hibernating chipmunks under the control of endogenous circannual rhythms. However, the molecular mechanisms that differentially regulate the HP-25 gene during the nonhibernation and hibernation seasons are unknown. Here, we show that the hibernation-associated HP-25 expression is regulated epigenetically. Chromatin immunoprecipitation analyses revealed that significantly less hepatocyte nuclear receptor HNF-4 bound to the HP-25 gene promoter in the liver of hibernating chipmunks compared to nonhibernating chipmunks. Concurrently in the hibernating chipmunks, coactivators were dissociated from the promoter, and active transcription histone marks on the HP-25 gene promoter were lost. On the other hand, small heterodimer partner (SHP) expression was upregulated in the liver of hibernating chipmunks. Overexpressing SHP in primary hepatocytes prepared from nonhibernating chipmunks caused HNF-4 to dissociate from the HP-25 gene promoter, and reduced the HP-25 mRNA level. These results suggest that hibernation-related HP-25 expression is epigenetically regulated by the binding of HNF-4 to the HP-25 promoter, and that this binding might be modulated by SHP in hibernating chipmunks.
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Affiliation(s)
| | - Michihiko Ito
- Kitasato University School of Science, Kanagawa 252-0373, Japan
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22
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Abstract
Endogenous long-term timing is a key component of seasonality. Where and how are such rhythms generated? Recent findings pointed to the pituitary pars tuberalis, already implicated in photoperiod responsiveness. Now, a new study provides mechanistic insights which support this hypothesis.
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23
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Dardente H, Lomet D, Robert V, Decourt C, Beltramo M, Pellicer-Rubio MT. Seasonal breeding in mammals: From basic science to applications and back. Theriogenology 2016; 86:324-32. [DOI: 10.1016/j.theriogenology.2016.04.045] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 02/02/2016] [Accepted: 03/14/2016] [Indexed: 12/29/2022]
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24
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Seasonal and post-trauma remodeling in cone-dominant ground squirrel retina. Exp Eye Res 2016; 150:90-105. [PMID: 26808487 DOI: 10.1016/j.exer.2016.01.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/14/2015] [Accepted: 01/14/2016] [Indexed: 02/02/2023]
Abstract
With a photoreceptor mosaic containing ∼85% cones, the ground squirrel is one of the richest known mammalian sources of these important retinal cells. It also has a visual ecology much like the human's. While the ground squirrel retina is understandably prominent in the cone biochemistry, physiology, and circuitry literature, far less is known about the remodeling potential of its retinal pigment epithelium, neurons, macroglia, or microglia. This review aims to summarize the data from ground squirrel retina to this point in time, and to relate them to data from other brain areas where appropriate. We begin with a survey of the ground squirrel visual system, making comparisons with traditional rodent models and with human. Because this animal's status as a hibernator often goes unnoticed in the vision literature, we then present a brief primer on hibernation biology. Next we review what is known about ground squirrel retinal remodeling concurrent with deep torpor and with rapid recovery upon re-warming. Notable here is rapidly-reversible, temperature-dependent structural plasticity of cone ribbon synapses, as well as pre- and post-synaptic plasticity throughout diverse brain regions. It is not yet clear if retinal cell types other than cones engage in torpor-associated synaptic remodeling. We end with the small but intriguing literature on the ground squirrel retina's remodeling responses to insult by retinal detachment. Notable for widespread loss of (cone) photoreceptors, there is surprisingly little remodeling of the RPE or Müller cells. Microglial activation appears minimal, and remodeling of surviving second- and third-order neurons seems absent, but both require further study. In contrast, traumatic brain injury in the ground squirrel elicits typical macroglial and microglial responses. Overall, the data to date strongly suggest a heretofore unrecognized, natural checkpoint between retinal deafferentiation and RPE and Müller cell remodeling events. As we continue to discover them, the unique ways by which ground squirrel retina responds to hibernation or injury may be adaptable to therapeutic use.
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25
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Ratigan ED, McKay DB. Exploring principles of hibernation for organ preservation. Transplant Rev (Orlando) 2015; 30:13-9. [PMID: 26613668 DOI: 10.1016/j.trre.2015.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 08/19/2015] [Accepted: 08/30/2015] [Indexed: 11/25/2022]
Abstract
Interest in mimicking hibernating states has led investigators to explore the biological mechanisms that permit hibernating mammals to survive for months at extremely low ambient temperatures, with no food or water, and awaken from their hibernation without apparent organ injury. Hibernators have evolved mechanisms to adapt to dramatic reductions in core body temperature and metabolic rate, accompanied by prolonged periods without nutritional intake and at the same time tolerate the metabolic demands of arousal. This review discusses the inherent resilience of hibernators to kidney injury and provides a potential framework for new therapies targeting ex vivo preservation of kidneys for transplantation.
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Affiliation(s)
- Emmett D Ratigan
- Division of Nephrology/Hypertension, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA
| | - Dianne B McKay
- Division of Nephrology/Hypertension, Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, USA.
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26
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"Seasonal changes in the neuroendocrine system": some reflections. Front Neuroendocrinol 2015; 37:3-12. [PMID: 25462591 DOI: 10.1016/j.yfrne.2014.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 11/13/2014] [Accepted: 11/13/2014] [Indexed: 12/12/2022]
Abstract
This perspective considers first the general issue of seasonality and how it is shaped ecologically. It asks what is the relative importance of "strategic" (photoperiod-dependent) versus "tactical" (supplemental) cues in seasonality and what neural circuits are involved? It then considers recent developments as reflected in the Special Issue. What don't we understand about the photoperiodic clock and also the long-term timing mechanisms underlying refractoriness? Are these latter related to the endogenous annual rhythms? Can we finally identify the opsins involved in photodetection? What is the present position with regard to melatonin as "the" annual calendar? An exciting development has been the recognition of the involvement of thyroid hormones in seasonality but how does the Dio/TSH/thyroid hormone pathway integrate with downstream components of the photoperiodic response system? Finally, there are the seasonal changes within the central nervous system itself--perhaps the most exciting aspect of all.
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