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Abstract
After cross-equatorial wintering, migratory birds reliably return to their natal grounds, but a population of cliff swallows recently switched breeding hemisphere. They inverted their annual cycle and migration directions almost instantaneously.
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Affiliation(s)
- Barbara Helm
- GELIFES - Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands; Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
| | - Rachel Muheim
- Department of Biology, Lund University, Lund, Sweden
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2
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Aymen J, Freedman M, Delnatte P, McAdie M, Beaufrère H. Retrospective analysis of hibernation parameters and breeding success in captive Vancouver Island marmots (Marmota vancouverensis): 1997-2018. Zoo Biol 2021; 40:273-279. [PMID: 33848361 DOI: 10.1002/zoo.21607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/05/2021] [Accepted: 03/24/2021] [Indexed: 11/07/2022]
Abstract
Vancouver Island marmots (Marmota vancouverensis) have been managed in a captive-breeding program since 1997, as in situ conservation efforts were insufficient in raising the numbers of this critically endangered species. The success of captive-breeding programs centers on sustainable reproduction and survival of individuals once released into the wild. Captive-born Vancouver Island marmots released to the wild have lower survival rates than their wild-born counterparts; this difference may arise from compromised hibernation patterns or behaviors. Hibernation duration, body weight over the hibernation season, and reproductive success of captive Vancouver Island marmots were reviewed to assess the effect of these variables on each other. Data from a total of 1782 hibernations and 456 breeding attempts were compiled from 1997 to 2018. The number of winters spent in captivity, the origin of the marmot (captive-born or wild-born), the facility at which hibernation occurred, and the body weight all had a significant effect on hibernation length (all p < .001). Increased weight was associated with increased hibernation length by 0.4 ± 0.1 day/kg on average (p = .0015). Captive, wild-born marmots hibernated for significantly longer than their captive-born counterparts by about 21 ± 2 days (p < .001). The odds of successful breeding were significantly increased with increasing hibernation length by approximatively 20% for every 10 additional days of hibernation. This study provides information on the intrinsic relationship between body weight, reproduction, and hibernation in captive Vancouver Island marmots.
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Affiliation(s)
- Jessica Aymen
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
- Toronto Zoo, Toronto, Ontario, Canada
| | - Megan Freedman
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | | | - Malcolm McAdie
- Marmot Recovery Foundation, Nanaimo, British Columbia, Canada
| | - Hugues Beaufrère
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
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3
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Helm B, Ben-Shlomo R, Sheriff MJ, Hut RA, Foster R, Barnes BM, Dominoni D. Annual rhythms that underlie phenology: biological time-keeping meets environmental change. Proc Biol Sci 2013; 280:20130016. [PMID: 23825201 DOI: 10.1098/rspb.2013.0016] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seasonal recurrence of biological processes (phenology) and its relationship to environmental change is recognized as being of key scientific and public concern, but its current study largely overlooks the extent to which phenology is based on biological time-keeping mechanisms. We highlight the relevance of physiological and neurobiological regulation for organisms' responsiveness to environmental conditions. Focusing on avian and mammalian examples, we describe circannual rhythmicity of reproduction, migration and hibernation, and address responses of animals to photic and thermal conditions. Climate change and urbanization are used as urgent examples of anthropogenic influences that put biological timing systems under pressure. We furthermore propose that consideration of Homo sapiens as principally a 'seasonal animal' can inspire new perspectives for understanding medical and psychological problems.
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Affiliation(s)
- Barbara Helm
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK.
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4
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Gómez-Brunet A, Santiago-Moreno J, Toledano-Díaz A, López-Sebastián A. Evidence that Refractoriness to Long and Short Daylengths Regulates Seasonal Reproductive Transitions in Mediterranean Goats. Reprod Domest Anim 2010; 45:e338-43. [DOI: 10.1111/j.1439-0531.2009.01571.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Antiviral effects of lamivudine, emtricitabine, adefovir dipivoxil, and tenofovir disoproxil fumarate administered orally alone and in combination to woodchucks with chronic woodchuck hepatitis virus infection. Antimicrob Agents Chemother 2008; 52:3617-32. [PMID: 18676881 DOI: 10.1128/aac.00654-08] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Adefovir dipivoxil (ADV) and tenofovir disoproxil fumarate (TDF) are nucleotide analogs that inhibit the replication of wild-type hepatitis B virus (HBV) and lamivudine (3TC)-resistant virus in HBV-infected patients, including those who are coinfected with human immunodeficiency virus. The combination of ADV or TDF with other nucleoside analogs is a proposed strategy for managing antiviral drug resistance during the treatment of chronic HBV infection. The antiviral effect of oral ADV or TDF, alone or in combination with 3TC or emtricitabine (FTC), against chronic woodchuck hepatitis virus (WHV) infection was evaluated in a placebo-controlled study in the woodchuck, an established and predictive model for antiviral therapy. Once-daily treatment for 48 weeks with ADV plus 3TC or TDF plus FTC significantly reduced serum WHV viremia levels from the pretreatment level by 6.2 log(10) and 6.1 log(10) genome equivalents/ml serum, respectively, followed by TDF plus 3TC (5.6 log(10) genome equivalents/ml), ADV alone (4.8 log(10) genome equivalents/ml), ADV plus FTC (one survivor) (4.4 log(10) genome equivalents/ml), TDF alone (2.9 log(10) genome equivalents/ml), 3TC alone (2.7 log(10) genome equivalents/ml), and FTC alone (2.0 log(10) genome equivalents/ml). Individual woodchucks across all treatment groups also demonstrated pronounced declines in serum WHV surface antigen, characteristically accompanied by declines in hepatic WHV replication and the hepatic expression of WHV antigens. Most woodchucks had prompt recrudescence of WHV replication after drug withdrawal, but individual woodchucks across treatment groups had sustained effects. No signs of toxicity were observed for any of the drugs or drug combinations administered. In conclusion, the oral administration of 3TC, FTC, ADV, and TDF alone and in combination was safe and effective in the woodchuck model of HBV infection.
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Gómez-Brunet A, Santiago-Moreno J, Campo AD, Malpaux B, Chemineau P, Tortonese DJ, Gonzalez-Bulnes A, López-Sebastián A. Endogenous Circannual Cycles of Ovarian Activity and Changes in Prolactin and Melatonin Secretion in Wild and Domestic Female Sheep Maintained under a Long-Day Photoperiod1. Biol Reprod 2008; 78:552-62. [DOI: 10.1095/biolreprod.107.064394] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Wang Y, Menne S, Baldwin BH, Tennant BC, Gerin JL, Cote PJ. Kinetics of viremia and acute liver injury in relation to outcome of neonatal woodchuck hepatitis virus infection. J Med Virol 2004; 72:406-15. [PMID: 14748064 DOI: 10.1002/jmv.20019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The kinetics of serum viral responses and acute liver injury were studied during neonatal woodchuck hepatitis virus (WHV) infection in relation to the chronic or resolved outcome. The mean concentrations of serum WHV DNA and surface antigen were significantly higher by week 10 post infection in chronic infections compared to resolving infections, and diverged even further by the time of peak viral load development in serum (week 12). After week 12, these viral markers were detected less frequently with time and at lower concentrations in the resolved outcome. In both outcomes, mean serum activities of hepatic enzymes became increased significantly above baseline by weeks 10-12, peaked at week 14, and normalized by weeks 20-22, thus indicating transient acute liver injury. The increasing liver injury responses were comparable between outcomes at week 12, when serum viral load was markedly higher in the developing chronic infections. This suggested a deficiency in early non-cytolytic control of infection in the chronic outcome. At week 14, liver injury was significantly greater in the resolved outcome and associated with higher mean Fas ligand (FasL) and perforin messenger RNAs (mRNAs) in liver compared to the chronic outcome. This indicated greater immune-mediated killing of infected hepatocytes during resolution. Thus, chronicity as an outcome of neonatal WHV infection develops relatively early during the acute phase of infection due to reduced immune-mediated clearance of infected hepatocytes by both cytolytic and non-cytolytic processes.
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MESH Headings
- Animals
- Animals, Newborn
- Antigens, Surface/blood
- Antigens, Viral/blood
- DNA, Viral/blood
- Disease Progression
- Enzymes/blood
- Fas Ligand Protein
- Gene Expression
- Hepatitis B/immunology
- Hepatitis B/pathology
- Hepatitis B/physiopathology
- Hepatitis B/virology
- Hepatitis B Virus, Woodchuck/growth & development
- Hepatitis B Virus, Woodchuck/immunology
- Hepatitis B Virus, Woodchuck/isolation & purification
- Hepatitis B, Chronic/immunology
- Hepatitis B, Chronic/pathology
- Hepatitis B, Chronic/physiopathology
- Hepatitis B, Chronic/virology
- Hepatitis, Viral, Animal/immunology
- Hepatitis, Viral, Animal/pathology
- Hepatitis, Viral, Animal/physiopathology
- Hepatitis, Viral, Animal/virology
- Kinetics
- Liver/pathology
- Marmota/virology
- Membrane Glycoproteins/analysis
- Membrane Glycoproteins/genetics
- Perforin
- Pore Forming Cytotoxic Proteins
- Viral Load
- Viremia/virology
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Affiliation(s)
- Yun Wang
- Division of Molecular Virology and Immunology, Department of Microbiology and Immunology, Georgetown University Medical Center, Rockville, Maryland 20852, USA
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8
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Armitage KB, Woods BC. Group Hibernation Does Not Reduce Energetic Costs of Young Yellow‐Bellied Marmots. Physiol Biochem Zool 2003; 76:888-98. [PMID: 14988804 DOI: 10.1086/378137] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We investigated mechanisms of energy conservation during hibernation. The amount of time torpid was significantly less for groups of three young marmots than for marmots hibernating singly. Mean daily mass loss (DML; as mg d(-1) g(-1) immergence mass) averaged 1.33 for single marmots and 1.46 for grouped young. Animals were active 17.3% of the time, which used 82.4% of the energy, and were torpid 82.7% of the time, which used 17.6% of the energy expenditure. During longer torpor bouts, more time was spent in deep torpor, which decreased the hourly cost of a complete bout. Bout oxygen consumption V dot o2, percent time in deep torpor, and body temperature (T(B)) during deep torpor changed seasonally and were curvilinearly related to when in the hibernation period the measurements were made and probably represent a stage in the circannual metabolic cycle. The decrease of environmental temperature (T(E)) to 2 degrees C significantly increased metabolism. Potential costs of low T(E) were reduced by allowing T(B) to decrease, thereby reducing the T(B) to T(E) gradient. Average monthly metabolic rate was high early and late in the hibernation period when time spent euthermic was greater and when VO2 was higher. Over the hibernation period, energy saved averaged 77.1% and 88.0% of the costs for winter and summer euthermic metabolism, respectively. Hibernation costs were reduced by the seasonal changes, the high percentage of time in torpor, the rapid decline in V dot o2 following arousal, and allowing T(B) to decline at lower T(E). Asynchrony in the torpor cycles increased energy expenditures in group hibernators, which negated possible beneficial effects of group hibernation.
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Affiliation(s)
- Kenneth B Armitage
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045-7534, USA.
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9
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Wang Y, Menne S, Jacob JR, Tennant BC, Gerin JL, Cote PJ. Role of type 1 versus type 2 immune responses in liver during the onset of chronic woodchuck hepatitis virus infection. Hepatology 2003; 37:771-80. [PMID: 12668969 DOI: 10.1053/jhep.2003.50154] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Immune response messenger RNAs (mRNA) were compared in liver during self-limited (resolved) and chronic neonatal woodchuck hepatitis virus (WHV) infection. At week 14 postinfection (mid-acute phase), mRNAs for leukocyte markers (CD3, CD4, CD8), type 1 cytokines and related transcription factors (IFN-gamma, TNF-alpha, STAT4, T-bet), and IL-10 were increased in livers from resolving infections, but mRNAs of other type 1 (IL-2) and type 2 (IL-4, STAT6, and GATA3 markers remained at baseline levels. Increased coexpression of IFN-gamma and TNF-alpha mRNAs correlated in most cases with lower levels of intrahepatic WHV covalently closed circular DNA (cccDNA). At the same time point postinfection, livers from woodchucks that eventually progressed to chronic infection had baseline or slightly elevated levels of CD and type 1 mRNAs, which were significantly lower (or elevated less frequently) compared with resolving woodchucks. Earlier, at week 8, there were no differences between the two outcome settings. During these early time points and at a later stage in chronic infection (15 months), type 2 mRNAs in carrier liver remained at baseline levels or, when elevated, were never in excess of those in resolving woodchucks. In conclusion, the onset and maintenance of neonatal chronic WHV infection are not associated with antagonistic type 2 immunoregulation of type 1 responses in liver. Accordingly, chronicity develops in association with a primary deficiency in the intrahepatic CD responses, especially involving CD8(+) T lymphocytes, and in both extracellular (cytokine) and intracellular (transcriptional) type 1 response mediators. This has relevant implications for future treatment of chronic hepatitis B virus (HBV) infection in humans.
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Affiliation(s)
- Yun Wang
- Division of Molecular Virology and Immunology, Department of Microbiology and Immunology, Georgetown University Medical Center, Rockville, MD 20850, USA.
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10
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Malpaux B, Migaud M, Tricoire H, Chemineau P. Biology of mammalian photoperiodism and the critical role of the pineal gland and melatonin. J Biol Rhythms 2001; 16:336-47. [PMID: 11506379 DOI: 10.1177/074873001129002051] [Citation(s) in RCA: 248] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In mammals, photoperiodic information is transformed into a melatonin secretory rhythm in the pineal gland (high levels at night, low levels during the day). Melatonin exerts its effects in discrete hypothalamic areas, most likely through MT1 melatonin receptors. Whether melatonin is brought to the hypothalamus from the cerebrospinal fluid or the blood is still unclear. The final action of this indoleamine at the level of the central nervous system is a modulation of GnRH secretion but it does not act directly on GnRH neurones; rather, its action involves a complex neural circuit of interneurones that includes at least dopaminergic, serotoninergic and aminoacidergic neurones. In addition, this network appears to undergo morphological changes between seasons.
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Affiliation(s)
- B Malpaux
- UMR 6073 INRA-CNRS-Université François Rabelais, Physiologie de la Reproduction et des Comportements, Nouzilly, France.
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11
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Barrell GK, Thrun LA, Brown ME, Viguié C, Karsch FJ. Importance of photoperiodic signal quality to entrainment of the circannual reproductive rhythm of the ewe. Biol Reprod 2000; 63:769-74. [PMID: 10952919 DOI: 10.1095/biolreprod63.3.769] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
An endogenous circannual rhythm drives the seasonal reproductive cycle of a broad spectrum of species. This rhythm is synchronized to the seasons (i.e., entrained) by photoperiod, which acts by regulating the circadian pattern of melatonin secretion from the pineal gland. Prior work has revealed that melatonin patterns secreted in spring/summer entrain the circannual rhythm of reproductive neuroendocrine activity in sheep, whereas secretions in winter do not. The goal of this study was to determine if inability of the winter-melatonin pattern to entrain the rhythm is due to the specific melatonin pattern secreted in winter or to the stage of the circannual rhythm at that time of year. Either a summer- or a winter-melatonin pattern was infused for 70 days into pinealectomized ewes, centered around the summer solstice, when an effective stimulus readily entrains the rhythm. The ewes were ovariectomized and treated with constant-release estradiol implants, and circannual cycles of reproductive neuroendocrine activity were monitored by serum LH concentrations. Only the summer-melatonin pattern entrained the circannual reproductive rhythm. The inability of the winter pattern to do so indicates that the mere presence of a circadian melatonin pattern, in itself, is insufficient for entrainment. Rather, the characteristics of the melatonin pattern, in particular a pattern that mimics the photoperiodic signals of summer, determines entrainment of the circannual rhythm of reproductive neuroendocrine activity in the ewe.
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Affiliation(s)
- G K Barrell
- Reproductive Sciences Program, Department of Physiology, University of Michigan, Ann Arbor, Michigan 48109-0404, USA
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12
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Hiebert SM, Thomas EM, Lee TM, Pelz KM, Yellon SM, Zucker I. Photic entrainment of circannual rhythms in golden-mantled ground squirrels: role of the pineal gland. J Biol Rhythms 2000; 15:126-34. [PMID: 10762031 DOI: 10.1177/074873040001500207] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Entrainment of circannual rhythms of body mass and reproduction was monitored for 3 years in female golden-mantled ground squirrels maintained in a simulated natural photoperiod. Both pinealectomized and pineal-intact squirrels generated circannual rhythms of body mass and estrus, but only the intact animals entrained these rhythms to a period of 365 days. In the second and third years after treatment, the period of the body mass rhythm was significantly shorter than 365 days for pinealectomized squirrels, and variance in tau among these animals was significantly greater than for intact squirrels. A similar pattern was evident in the rhythm of reproduction, which was phase-disrupted in pinealectomized squirrels but entrained in intacts. Seasonal changes in duration of nocturnal melatonin secretion by the pineal appear to be necessary to produce phase-delays required to entrain the circannual clock to a period of 12 months.
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Affiliation(s)
- S M Hiebert
- Department of Biology, Swarthmore College, PA 19081, USA
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13
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Concannon PW, Castracane VD, Rawson RE, Tennant BC. Circannual changes in free thyroxine, prolactin, testes, and relative food intake in woodchucks, Marmota monax. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:R1401-9. [PMID: 10564213 DOI: 10.1152/ajpregu.1999.277.5.r1401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Woodchucks (n = 12-14/group) with circannual cycles entrained to northern versus southern hemisphere photoperiods were assessed monthly for 16 mo. Changes in serum total triiodothyronine (TT(3)), free thyroxine (T(4)), total thyroxine (TT(4)), and prolactin were determined in a subset of five animals per group. Metabolic hormone results were examined in relation to changes in body weight, food intake, and serum testosterone (n = 12-14/group). Seasonal changes in each parameter were similar in both groups as were nadir and peak TT(3) (162 +/- 6 and 392 +/- 12 ng/ml, respectively), free T(4) (19 +/- 2 and 86 +/- 7 ng/ml, repectively), TT(4) (3.2 +/- 0.2 and 8.0 +/- 0.5 ng/ml, respectively), and prolactin (0.6 +/- 0.1 and 14 +/- 2 ng/ml, respectively). In late winter and early spring, simultaneous increases in both free T(4) and prolactin were associated with 1) a large increase in food intake, 2) a decline in body weight to nadir values, 3) a corresponding negative energy balance, 4) a peak and decline in serum testosterone, and 5) a modest increase in TT(4) and large decline in serum TT(3). Low levels of free T(4) and prolactin were observed in summer when energy balance was very positive. The results demonstrate that, in woodchucks, serum T(4) and prolactin undergo seasonal changes during annual cycles entrained by photoperiod. The results suggest that changes in free T(4), acting as a calorigenic hormone, and changes in both T(4) and prolactin, potentially acting as lipolytic, antilipogenic, and/or orectic hormones, are likely involved in the mechanisms underlying the corresponding seasonal changes in food intake, fat metabolism, and energy balance in this species. Their potential roles in gonadal regression and recrudescence are less clear.
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Affiliation(s)
- P W Concannon
- Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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