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Hervas LS, do Amaral-Silva L, Sartori MR, Guadalupe-Silva A, Gargaglioni LH, Lerchner J, Oliveira MT, Bícego KC. Mitochondrial function in skeletal muscle contributes to reproductive endothermy in tegu lizards (Salvator merianae). Acta Physiol (Oxf) 2024; 240:e14162. [PMID: 38741523 DOI: 10.1111/apha.14162] [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: 10/31/2023] [Revised: 04/17/2024] [Accepted: 04/28/2024] [Indexed: 05/16/2024]
Abstract
AIM In cyclic climate variations, including seasonal changes, many animals regulate their energy demands to overcome critical transitory moments, restricting their high-demand activities to phases of resource abundance, enabling rapid growth and reproduction. Tegu lizards (Salvator merianae) are ectotherms with a robust annual cycle, being active during summer, hibernating during winter, and presenting a remarkable endothermy during reproduction in spring. Here, we evaluated whether changes in mitochondrial respiratory physiology in skeletal muscle could serve as a mechanism for the increased thermogenesis observed during the tegu's reproductive endothermy. METHODS We performed high-resolution respirometry and calorimetry in permeabilized red and white muscle fibers, sampled during summer (activity) and spring (high activity and reproduction), in association with citrate synthase measurements. RESULTS During spring, the muscle fibers exhibited increased oxidative phosphorylation. They also enhanced uncoupled respiration and heat production via adenine nucleotide translocase (ANT), but not via uncoupling proteins (UCP). Citrate synthase activity was higher during the spring, suggesting greater mitochondrial density compared to the summer. These findings were consistent across both sexes and muscle types (red and white). CONCLUSION The current results highlight potential cellular thermogenic mechanisms in an ectothermic reptile that contribute to transient endothermy. Our study indicates that the unique feature of transitioning to endothermy through nonshivering thermogenesis during the reproductive phase may be facilitated by higher mitochondrial density, function, and uncoupling within the skeletal muscle. This knowledge contributes significant elements to the broader picture of models for the evolution of endothermy, particularly in relation to the enhancement of aerobic capacity.
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Affiliation(s)
- Livia Saccani Hervas
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
| | - Lara do Amaral-Silva
- Department of Biology, Wake Forest University, Winston Salem, North Carolina, USA
| | - Marina Rincon Sartori
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Ane Guadalupe-Silva
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
| | - Johannes Lerchner
- Institute of Physical Chemistry, TU Bergakademie Freiberg, Freiberg, Germany
| | | | - Kênia Cardoso Bícego
- Department of Animal Morphology and Physiology, São Paulo State University, Jaboticabal, Brazil
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2
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González-Morales JC, Rivera-Rea J, Moreno-Rueda G, Plasman M, Quintana E, Bastiaans E. Seasonal and altitudinal variation in dorsal skin reflectance and thermic rates in a high-altitude montane lizard. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2024:10.1007/s00484-024-02677-7. [PMID: 38652160 DOI: 10.1007/s00484-024-02677-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 02/26/2024] [Accepted: 04/01/2024] [Indexed: 04/25/2024]
Abstract
Temperature is one of the most important factors in the life histories of ectotherms, as body temperature has an undeniable effect on growth, activity, and reproduction. Lizards have a wide variety of strategies to acquire and maintain body temperature in an optimal range. The "Thermal Melanism Hypothesis" proposes that individuals with lower skin reflectance can heat up faster as a result of absorbing more solar radiation compared to lighter conspecifics. Therefore, having a darker coloration might be advantageous in cold habitats. Dorsal skin reflectance has been found to change rapidly with body temperature in several lizard species, and it can also vary over longer, seasonal time scales. These variations may be important in thermoregulation, especially in lizards that inhabit areas with a large temperature variation during the year. Here, we study how dorsal reflectance fluctuates with body temperature and varies among seasons. We compared dorsal skin reflectance at three body temperature treatments, and measured thermal rates (i.e., heat and cool rate, thermic lapse, and net heat gain) by elevation (2500-4100 m) and seasons (spring, summer, and autumn) in the mesquite lizard, Sceloporus grammicus. Our results show that lizards were darker at high elevations and during the months with the lowest environmental temperatures. The rate of obtaining and retaining heat also varied during the year and was highest during the reproductive season. Our results indicate that the variation of dorsal skin reflectance and thermal rates follows a complex pattern in lizard populations and is affected by both elevation and season.
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Affiliation(s)
- J Carlos González-Morales
- Centro Universitario Amecameca, Universidad Autónoma del Estado de México, Estado de México, Instituto Literario No. 100, Col. Centro, Toluca, CP 50000, México.
| | - Jimena Rivera-Rea
- Doctorado en Ciencias Agropecuarias y Recursos Naturales, Universidad Autónoma del Estado de México, Instituto Literario No. 100, Col. Centro, Toluca, Estado de México, CP 50000, México
| | - Gregorio Moreno-Rueda
- Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, Avenida Fuentenueva S/N, Granda, E-18071, España
| | - Melissa Plasman
- Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito exterior S/N, Ciudad Universitaria, Coyoacán, Ciudad de México, 04510, México
| | - Erendira Quintana
- Centro Universitario Amecameca, Universidad Autónoma del Estado de México, Estado de México, Instituto Literario No. 100, Col. Centro, Toluca, CP 50000, México
| | - Elizabeth Bastiaans
- Biology Departament, State University of New York at Oneonta, 108 Ravine Parkway, Oneonta, NY, 13820, USA
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3
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Giacometti D, Palaoro AV, Leal LC, de Barros FC. How seasonality influences the thermal biology of lizards with different thermoregulatory strategies: a meta-analysis. Biol Rev Camb Philos Soc 2024; 99:409-429. [PMID: 37872698 DOI: 10.1111/brv.13028] [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: 11/24/2022] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023]
Abstract
Ectotherms that maintain thermal balance in the face of varying climates should be able to colonise a wide range of habitats. In lizards, thermoregulation usually appears as a variety of behaviours that buffer external influences over physiology. Basking species rely on solar radiation to raise body temperatures and usually show high thermoregulatory precision. By contrast, species that do not bask are often constrained by climatic conditions in their habitats, thus having lower thermoregulatory precision. While much focus has been given to the effects of mean habitat temperatures, relatively less is known about how seasonality affects the thermal biology of lizards on a macroecological scale. Considering the current climate crisis, assessing how lizards cope with temporal variations in environmental temperature is essential to understand better how these organisms will fare under climate change. Activity body temperatures (Tb ) represent the internal temperature of an animal measured in nature during its active period (i.e. realised thermal niche), and preferred body temperatures (Tpref ) are those selected by an animal in a laboratory thermal gradient that lacks thermoregulatory costs (i.e. fundamental thermal niche). Both traits form the bulk of thermal ecology research and are often studied in the context of seasonality. In this study, we used a meta-analysis to test how environmental temperature seasonality influences the seasonal variation in the Tb and Tpref of lizards that differ in thermoregulatory strategy (basking versus non-basking). Based on 333 effect sizes from 137 species, we found that Tb varied over a greater magnitude than Tpref across seasons. Variations in Tb were not influenced by environmental temperature seasonality; however, body size and thermoregulatory strategy mediated Tb responses. Specifically, larger species were subjected to greater seasonal variations in Tb , and basking species endured greater seasonal variations in Tb compared to non-basking species. On the other hand, the seasonal variation in Tpref increased with environmental temperature seasonality regardless of body size. Thermoregulatory strategy also influenced Tpref , suggesting that behaviour has an important role in mediating Tpref responses to seasonal variations in the thermal landscape. After controlling for phylogenetic effects, we showed that Tb and Tpref varied significantly across lizard families. Taken together, our results support the notion that the relationship between thermal biology responses and climatic parameters can be taxon and trait dependent. Our results also showcase the importance of considering ecological and behavioural aspects in macroecological studies. We further highlight current systematic, geographical, and knowledge gaps in thermal ecology research. Our work should benefit those who aim to understand more fully how seasonality shapes thermal biology in lizards, ultimately contributing to the goal of elucidating the evolution of temperature-sensitive traits in ectotherms.
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Affiliation(s)
- Danilo Giacometti
- Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Rua Professor Artur Riedel 275, Diadema, São Paulo, 09972-270, Brasil
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S3A1, Canada
| | - Alexandre V Palaoro
- Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Rua Professor Artur Riedel 275, Diadema, São Paulo, 09972-270, Brasil
- Department of Material Sciences and Engineering, 490 Sirrine Hall, Clemson University, 515 Calhoun Dr, Clemson, SC, 29634, USA
- Programa de Pós-Graduação em Ecologia, Universidade de São Paulo, Rua do Matão Trav. 14, São Paulo, 05508-090, Brasil
- Departamento de Zoologia, Universidade Federal do Paraná, Avenida Coronel Francisco H. dos Santos 100, Curitiba, Paraná, 82590-300, Brasil
| | - Laura C Leal
- Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Rua Professor Artur Riedel 275, Diadema, São Paulo, 09972-270, Brasil
| | - Fábio C de Barros
- Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Rua Professor Artur Riedel 275, Diadema, São Paulo, 09972-270, Brasil
- Departamento de Biociências, Universidade do Estado de Minas Gerais, Avenida Juca Stockler 1130, Passos, Minas Gerais, 37900-106, Brasil
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4
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Kuroda KO, Fukumitsu K, Kurachi T, Ohmura N, Shiraishi Y, Yoshihara C. Parental brain through time: The origin and development of the neural circuit of mammalian parenting. Ann N Y Acad Sci 2024; 1534:24-44. [PMID: 38426943 DOI: 10.1111/nyas.15111] [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] [Indexed: 03/02/2024]
Abstract
This review consolidates current knowledge on mammalian parental care, focusing on its neural mechanisms, evolutionary origins, and derivatives. Neurobiological studies have identified specific neurons in the medial preoptic area as crucial for parental care. Unexpectedly, these neurons are characterized by the expression of molecules signaling satiety, such as calcitonin receptor and BRS3, and overlap with neurons involved in the reproductive behaviors of males but not females. A synthesis of comparative ecology and paleontology suggests an evolutionary scenario for mammalian parental care, possibly stemming from male-biased guarding of offspring in basal vertebrates. The terrestrial transition of tetrapods led to prolonged egg retention in females and the emergence of amniotes, skewing care toward females. The nocturnal adaptation of Mesozoic mammalian ancestors reinforced maternal care for lactation and thermal regulation via endothermy, potentially introducing metabolic gate control in parenting neurons. The established maternal care may have served as the precursor for paternal and cooperative care in mammals and also fostered the development of group living, which may have further contributed to the emergence of empathy and altruism. These evolution-informed working hypotheses require empirical validation, yet they offer promising avenues to investigate the neural underpinnings of mammalian social behaviors.
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Affiliation(s)
- Kumi O Kuroda
- RIKEN Center for Brain Science, Saitama, Japan
- School of Life Sciences and Technologies, Tokyo Institute of Technology, Kanagawa, Japan
| | - Kansai Fukumitsu
- RIKEN Center for Brain Science, Saitama, Japan
- Department of Physiology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Takuma Kurachi
- RIKEN Center for Brain Science, Saitama, Japan
- Department of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Nami Ohmura
- RIKEN Center for Brain Science, Saitama, Japan
- Center for Brain, Mind and Kansei Sciences Research, Hiroshima University, Hiroshima, Japan
| | - Yuko Shiraishi
- RIKEN Center for Brain Science, Saitama, Japan
- Kawamura Gakuen Woman's University, Chiba, Japan
| | - Chihiro Yoshihara
- RIKEN Center for Brain Science, Saitama, Japan
- School of Life Sciences and Technologies, Tokyo Institute of Technology, Kanagawa, Japan
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5
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 4: evolution, thermal adaptation and unsupported theories of thermoregulation. Eur J Appl Physiol 2024; 124:147-218. [PMID: 37796290 DOI: 10.1007/s00421-023-05262-9] [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: 02/06/2023] [Accepted: 06/13/2023] [Indexed: 10/06/2023]
Abstract
This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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6
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Karameta E, Gavriilidi I, Sfenthourakis S, Pafilis P. Seasonal Variation in the Thermoregulation Pattern of an Insular Agamid Lizard. Animals (Basel) 2023; 13:3195. [PMID: 37893919 PMCID: PMC10603691 DOI: 10.3390/ani13203195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/08/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Ectotherms, including lizards, rely on behavioral thermoregulation to maintain their body temperature within an optimal range. The benign climate of islands is expected to favor the thermoregulation efficiency of reptiles throughout their activity period. In this study, we investigated the seasonal variation in thermoregulation in an insular population of the roughtail rock agama (Laudakia stellio) on Naxos Island, Greece. We measured body, operative, and preferred temperatures across three seasons (spring, summer, and autumn), and we evaluated the effectiveness of thermoregulation, using the Hertz index (E). Our results revealed that the effectiveness of thermoregulation was significantly influenced by seasonality. E was quite high in summer (0.97) and spring (0.92), and lowest in autumn (0.81). Accordingly, the quality of the thermal environment was significantly low during autumn, and maximum during summer. However, despite the environmental temperature fluctuations, lizards exhibited remarkable stability in body temperatures. They also adjusted their preferred temperatures seasonally and doubled the thermal niche breadth they occupied during summer, thus enhancing thermoregulation efficiency. Whether or not these adjustments are plastic or fixed local adaptations remains to be explored in further research across multiple years and seasons, including additional insular populations.
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Affiliation(s)
- Emmanouela Karameta
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Ilissia, 15784 Athens, Greece; (I.G.); (P.P.)
| | - Ioanna Gavriilidi
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Ilissia, 15784 Athens, Greece; (I.G.); (P.P.)
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Spyros Sfenthourakis
- Department of Biological Sciences, University of Cyprus, Panepistimiou 1, 2109 Nicosia, Cyprus;
| | - Panayiotis Pafilis
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Panepistimiopolis, Ilissia, 15784 Athens, Greece; (I.G.); (P.P.)
- Zoological Museum, National and Kapodistrian University of Athens, Panepistimioupolis, 15784 Athens, Greece
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7
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Motani R, Gold DA, Carlson SJ, Vermeij GJ. Amniote metabolism and the evolution of endothermy. Nature 2023; 621:E1-E3. [PMID: 37674001 DOI: 10.1038/s41586-023-06411-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 07/06/2023] [Indexed: 09/08/2023]
Affiliation(s)
- Ryosuke Motani
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, USA
| | - David A Gold
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, USA
| | - Sandra J Carlson
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, USA
| | - Geerat J Vermeij
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, USA.
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8
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Tagliavento M, Davies AJ, Bernecker M, Staudigel PT, Dawson RR, Dietzel M, Götschl K, Guo W, Schulp AS, Therrien F, Zelenitsky DK, Gerdes A, Müller W, Fiebig J. Evidence for heterothermic endothermy and reptile-like eggshell mineralization in Troodon, a non-avian maniraptoran theropod. Proc Natl Acad Sci U S A 2023; 120:e2213987120. [PMID: 37011196 PMCID: PMC10104568 DOI: 10.1073/pnas.2213987120] [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: 08/15/2022] [Accepted: 02/15/2023] [Indexed: 04/05/2023] Open
Abstract
The dinosaur-bird transition involved several anatomical, biomechanical, and physiological modifications of the theropod bauplan. Non-avian maniraptoran theropods, such as Troodon, are key to better understand changes in thermophysiology and reproduction occurring during this transition. Here, we applied dual clumped isotope (Δ47 and Δ48) thermometry, a technique that resolves mineralization temperature and other nonthermal information recorded in carbonates, to eggshells from Troodon, modern reptiles, and modern birds. Troodon eggshells show variable temperatures, namely 42 and 29 ± 2 °C, supporting the hypothesis of an endothermic thermophysiology with a heterothermic strategy for this extinct taxon. Dual clumped isotope data also reveal physiological differences in the reproductive systems between Troodon, reptiles, and birds. Troodon and modern reptiles mineralize their eggshells indistinguishable from dual clumped isotope equilibrium, while birds precipitate eggshells characterized by a positive disequilibrium offset in Δ48. Analyses of inorganic calcites suggest that the observed disequilibrium pattern in birds is linked to an amorphous calcium carbonate (ACC) precursor, a carbonate phase known to accelerate eggshell formation in birds. Lack of disequilibrium patterns in reptile and Troodon eggshells implies these vertebrates had not acquired the fast, ACC-based eggshell calcification process characteristic of birds. Observation that Troodon retained a slow reptile-like calcification suggests that it possessed two functional ovaries and was limited in the number of eggs it could produce; thus its large clutches would have been laid by several females. Dual clumped isotope analysis of eggshells of extinct vertebrates sheds light on physiological information otherwise inaccessible in the fossil record.
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Affiliation(s)
- Mattia Tagliavento
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Amelia J. Davies
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Miguel Bernecker
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Philip T. Staudigel
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Robin R. Dawson
- Department of Earth, Geographic and Climate Sciences, University of Massachusetts, Amherst, MA01003
| | - Martin Dietzel
- Institute of Applied Geosciences, Graz University of Technology,8010Graz, Austria
| | - Katja Götschl
- Institute of Applied Geosciences, Graz University of Technology,8010Graz, Austria
| | - Weifu Guo
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA02543
| | - Anne S. Schulp
- Vertebrate Evolution and Development, Naturalis Biodiversity Center,2333CRLeiden, the Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Universiteit Utrecht,3584 CBUtrecht, the Netherlands
| | | | | | - Axel Gerdes
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
- Frankfurt Isotope and Element Research Center, Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Wolfgang Müller
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
- Frankfurt Isotope and Element Research Center, Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Jens Fiebig
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
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Oliveira PRCD, Abe AS, Klein W. Temperature effects on oxygen consumption and breathing pattern in juvenile and adult Chelonoidis carbonarius (Spix, 1824). Respir Physiol Neurobiol 2023; 307:103978. [DOI: 10.1016/j.resp.2022.103978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/13/2022] [Accepted: 10/09/2022] [Indexed: 11/07/2022]
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10
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Gregorovicova M, Bartos M, Jensen B, Janacek J, Minne B, Moravec J, Sedmera D. Anguimorpha as a model group for studying the comparative heart morphology among Lepidosauria: Evolutionary window on the ventricular septation. Ecol Evol 2022; 12:e9476. [PMID: 36381397 PMCID: PMC9643144 DOI: 10.1002/ece3.9476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/11/2022] Open
Abstract
The group Anguimorpha represents one of the most unified squamate clades in terms of body plan, ecomorphology, ecophysiology and evolution. On the other hand, the anguimorphs vary between different habitats and ecological niches. Therefore, we focused on the group Anguimorpha to test a possible correlation between heart morphology and ecological niche with respect to phylogenetic position in Squamata with Sphenodon, Salvator, and Pogona as the outgroups. The chosen lepidosaurian species were investigated by microCT. Generally, all lepidosaurs had two well‐developed atria with complete interatrial septum and one ventricle divided by ventricular septa to three different areas. The ventricles of all lepidosaurians had a compact layer and abundant trabeculae. The compact layer and trabeculae were developed in accordance with particular ecological niche of the species, the trabeculae in nocturnal animals with low metabolism, such as Sphenodon, Heloderma or Lanthanotus were more massive. On the other hand athletic animals, such as varanids or Salvator, had ventricle compartmentalization divided by three incomplete septa. A difference between varanids and Salvator was found in compact layer thickness: thicker in monitor lizards and possibly linked to their mammalian‐like high blood pressure, and the level of ventricular septation. In summary: heart morphology varied among clades in connection with the ecological niche of particular species and it reflects the phylogenetic position in model clade Anguimorpha. In the absence of fossil evidence, this is the closest approach how to understand heart evolution and septation in clade with different cardiac compartmentalization levels.
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Affiliation(s)
- Martina Gregorovicova
- First Faculty of Medicine, Institute of Anatomy Charles University Prague Czech Republic
| | - Martin Bartos
- First Faculty of Medicine, Institute of Anatomy Charles University Prague Czech Republic
- First Faculty of Medicine Institute of Dental Medicine, Charles University Prague Czech Republic
| | - Bjarke Jensen
- Department of Medical Biology, Amsterdam Cardiovascular Sciences University of Amsterdam Amsterdam The Netherlands
| | - Jiri Janacek
- Laboratory of Biomathematics, Institute of Physiology Czech Academy of Sciences Prague Czech Republic
| | - Bryan Minne
- Amphibian Evolution Lab Free University of Brussels Brussels Belgium
| | | | - David Sedmera
- First Faculty of Medicine, Institute of Anatomy Charles University Prague Czech Republic
- Laboratory of Developmental Cardiology, Institute of Physiology Czech Academy of Sciences Prague Czech Republic
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11
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Muramatsu D, Vidal LV, Costa ER, Yoda K, Yabe T, Gordo M. Low-cost thermoregulation of wild sloths revealed by heart rate and temperature loggers. J Therm Biol 2022; 110:103387. [DOI: 10.1016/j.jtherbio.2022.103387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 10/20/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022]
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12
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Wiemann J, Menéndez I, Crawford JM, Fabbri M, Gauthier JA, Hull PM, Norell MA, Briggs DEG. Fossil biomolecules reveal an avian metabolism in the ancestral dinosaur. Nature 2022; 606:522-526. [PMID: 35614213 DOI: 10.1038/s41586-022-04770-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/19/2022] [Indexed: 11/09/2022]
Abstract
Birds and mammals independently evolved the highest metabolic rates among living animals1. Their metabolism generates heat that enables active thermoregulation1, shaping the ecological niches they can occupy and their adaptability to environmental change2. The metabolic performance of birds, which exceeds that of mammals, is thought to have evolved along their stem lineage3-10. However, there is no proxy that enables the direct reconstruction of metabolic rates from fossils. Here we use in situ Raman and Fourier-transform infrared spectroscopy to quantify the in vivo accumulation of metabolic lipoxidation signals in modern and fossil amniote bones. We observe no correlation between atmospheric oxygen concentrations11 and metabolic rates. Inferred ancestral states reveal that the metabolic rates consistent with endothermy evolved independently in mammals and plesiosaurs, and are ancestral to ornithodirans, with increasing rates along the avian lineage. High metabolic rates were acquired in pterosaurs, ornithischians, sauropods and theropods well before the advent of energetically costly adaptations, such as flight in birds. Although they had higher metabolic rates ancestrally, ornithischians reduced their metabolic abilities towards ectothermy. The physiological activities of such ectotherms were dependent on environmental and behavioural thermoregulation12, in contrast to the active lifestyles of endotherms1. Giant sauropods and theropods were not gigantothermic9,10, but true endotherms. Endothermy in many Late Cretaceous taxa, in addition to crown mammals and birds, suggests that attributes other than metabolism determined their fate during the terminal Cretaceous mass extinction.
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Affiliation(s)
- Jasmina Wiemann
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA.
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
- Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA.
| | - Iris Menéndez
- Departamento de Geodinámica, Estratigrafía y Paleontología, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, Madrid, Spain
- Departamento de Cambio Medioambiental, Instituto de Geociencias (UCM, CSIC), Madrid, Spain
| | | | - Matteo Fabbri
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA
| | - Jacques A Gauthier
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA
- Yale Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| | - Pincelli M Hull
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA
- Yale Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Derek E G Briggs
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA
- Yale Peabody Museum of Natural History, Yale University, New Haven, CT, USA
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13
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Betancourt S, Irizarry KJL, Falk BG, Rutllant J, Khamas W. Micromorphological study of the upper digestive tract of the Argentine tegu (Salvator merianae). Anat Histol Embryol 2022; 51:259-268. [PMID: 35083779 DOI: 10.1111/ahe.12786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 11/29/2022]
Abstract
Argentine black and white tegus (Salvator merianae) are omnivorous lizards native to southeastern Brazil, Uruguay, eastern Paraguay and northern Argentina, and are invasive species in Florida and Georgia, USA. They are opportunistic feeders, which is what allow them to have such a diverse variety of foods. Tegus raised a particular concern due to their adaptive capability to different environments. Our goal was to provide a micromorphology baseline of oesophagus and stomach and correlate findings with their dietary and invasive capabilities. Four Argentine black and white tegus were used for this study. We collected and processed specimens from oesophagus and stomach using standard histological techniques and stained tissue sections using Haematoxylin and Eosin (H&E), Periodic Acid Schiff (PAS), Alcian Blue (AB) and Verhoef's elastic stains. The oesophagus was lined with ciliated pseudostratified columnar epithelium (PSCE) with goblet cells. Gut-associated lymphoid tissues (GALT) were present occasionally in the oesophagus and more frequently in the stomach. Tunica muscularis (Tm) of the oesophageal-gastric junction had distinct smooth muscle which could function as a sphincter. The mucosa of the stomach was lined with simple columnar epithelium (SC). The glands had neck and dark oxyntico-peptic cells. The pyloric sphincter had more GALT and mucus cells than other regions. The Tm outer layer is thinner than the inner. Presence of large number of goblet cells would support faster transit of the bolus. The short digestive tract and the histological features observed are consistent with the ability of tegus consumption of large amount of food.
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Affiliation(s)
| | - Kristopher J L Irizarry
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
| | - Bryan Glenn Falk
- South Florida Natural Resources Center, Everglades National Park, Homestead, Florida, USA
| | - Josep Rutllant
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
| | - Wael Khamas
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, USA
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14
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Parlin AF, Schaeffer PJ. Cardiovascular contributions and energetic costs of thermoregulation in ectothermic vertebrates. J Exp Biol 2022; 225:274253. [PMID: 35119074 DOI: 10.1242/jeb.243095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/27/2021] [Indexed: 11/20/2022]
Abstract
Ectothermic vertebrates use a suite of physiological and behavioral mechanisms to thermoregulate, which result in various thermoregulatory strategies from thermoconformity to thermoregulation. Here, we present a novel synthesis of theoretical and empirical methods to determine cardiovascular contributions to heat transfer in free-living ectothermic vertebrates. We start by identifying the fundamental components of heat transfer and the cardiovascular mechanisms for physiological modulation of heat exchange, and then integrate these components into a single, integrative framework: the cardiovascular heat exchange framework (CHEF). We demonstrate that this framework can identify details of the thermoregulatory strategy in two turtle species, most notably the preponderance of instances where turtles use physiological mechanisms to avoid overheating, suggesting vulnerability to climate change. As modulated physiological contributions to heat flow incur a greater energy demand than relying on unmodulated passive heat transfer, we then asked whether we could characterize the energetic costs of thermoregulation. We measured field metabolic rate (FMR) in free-living turtles and used the CHEF to determine FMR while actively or passively thermoregulating. Comparing an individual's actual FMR to the rate calculated assuming absence of thermoregulation revealed that painted turtles, a partial thermoregulator, elevate their daily energy expenditure (DEE) by about 25%, while box turtles, a thermoconformer, have a DEE that is nearly unchanged as a result of thermoregulation. This integrative framework builds a new paradigm that provides a mechanism to explain correlations between energy demand and thermoregulatory strategy, quantifies the energetic costs of thermoregulation, and identifies the role of cardiovascular contributions to thermoregulation in free-living animals.
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Affiliation(s)
- Adam F Parlin
- Department of Biology, Miami University, Oxford, OH 45056, USA
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15
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Knaus PL, van Heteren AH, Lungmus JK, Sander PM. High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.751238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Varanids are the only non-avian sauropsids that are known to approach the warm-blooded mammals in stamina. Furthermore, a much higher maximum metabolic rate (MMR) gives endotherms (including birds) higher stamina than crocodiles, turtles, and non-varanid lepidosaurs. This has led researchers to hypothesize that mammalian endothermy evolved as a second step after the acquisition of elevated MMR in non-mammalian therapsids from a plesiomorphic state of low metabolic rates. In recent amniotes, MMR correlates with the index of blood flow into the femur (Qi), which is calculated from femoral length and the cross-sectional area of the nutrient foramen. Thus, Qi may serve as an indicator of MMR range in extinct animals. Using the Qi proxy and phylogenetic eigenvector maps, here we show that elevated MMRs evolved near the base of Synapsida. Non-mammalian synapsids, including caseids, edaphosaurids, sphenacodontids, dicynodonts, gorgonopsids, and non-mammalian cynodonts, show Qi values in the range of recent endotherms and varanids, suggesting that raised MMRs either evolved in synapsids shortly after the Synapsida-Sauropsida split in the Mississippian or that the low MMR of lepidosaurs and turtles is apomorphic, as has been postulated for crocodiles.
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Grigg G, Nowack J, Bicudo JEPW, Bal NC, Woodward HN, Seymour RS. Whole-body endothermy: ancient, homologous and widespread among the ancestors of mammals, birds and crocodylians. Biol Rev Camb Philos Soc 2021; 97:766-801. [PMID: 34894040 PMCID: PMC9300183 DOI: 10.1111/brv.12822] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 12/31/2022]
Abstract
The whole‐body (tachymetabolic) endothermy seen in modern birds and mammals is long held to have evolved independently in each group, a reasonable assumption when it was believed that its earliest appearances in birds and mammals arose many millions of years apart. That assumption is consistent with current acceptance that the non‐shivering thermogenesis (NST) component of regulatory body heat originates differently in each group: from skeletal muscle in birds and from brown adipose tissue (BAT) in mammals. However, BAT is absent in monotremes, marsupials, and many eutherians, all whole‐body endotherms. Indeed, recent research implies that BAT‐driven NST originated more recently and that the biochemical processes driving muscle NST in birds, many modern mammals and the ancestors of both may be similar, deriving from controlled ‘slippage’ of Ca2+ from the sarcoplasmic reticulum Ca2+‐ATPase (SERCA) in skeletal muscle, similar to a process seen in some fishes. This similarity prompted our realisation that the capacity for whole‐body endothermy could even have pre‐dated the divergence of Amniota into Synapsida and Sauropsida, leading us to hypothesise the homology of whole‐body endothermy in birds and mammals, in contrast to the current assumption of their independent (convergent) evolution. To explore the extent of similarity between muscle NST in mammals and birds we undertook a detailed review of these processes and their control in each group. We found considerable but not complete similarity between them: in extant mammals the ‘slippage’ is controlled by the protein sarcolipin (SLN), in birds the SLN is slightly different structurally and its role in NST is not yet proved. However, considering the multi‐millions of years since the separation of synapsids and diapsids, we consider that the similarity between NST production in birds and mammals is consistent with their whole‐body endothermy being homologous. If so, we should expect to find evidence for it much earlier and more widespread among extinct amniotes than is currently recognised. Accordingly, we conducted an extensive survey of the palaeontological literature using established proxies. Fossil bone histology reveals evidence of sustained rapid growth rates indicating tachymetabolism. Large body size and erect stature indicate high systemic arterial blood pressures and four‐chambered hearts, characteristic of tachymetabolism. Large nutrient foramina in long bones are indicative of high bone perfusion for rapid somatic growth and for repair of microfractures caused by intense locomotion. Obligate bipedality appeared early and only in whole‐body endotherms. Isotopic profiles of fossil material indicate endothermic levels of body temperature. These proxies led us to compelling evidence for the widespread occurrence of whole‐body endothermy among numerous extinct synapsids and sauropsids, and very early in each clade's family tree. These results are consistent with and support our hypothesis that tachymetabolic endothermy is plesiomorphic in Amniota. A hypothetical structure for the heart of the earliest endothermic amniotes is proposed. We conclude that there is strong evidence for whole‐body endothermy being ancient and widespread among amniotes and that the similarity of biochemical processes driving muscle NST in extant birds and mammals strengthens the case for its plesiomorphy.
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Affiliation(s)
- Gordon Grigg
- School of Biological Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Julia Nowack
- School of Biological and Environmental Sciences, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool, L3 3AF, U.K
| | | | | | - Holly N Woodward
- Oklahoma State University Center for Health Sciences, Tulsa, OK, 74107, U.S.A
| | - Roger S Seymour
- School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
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Giacometti D, Yagi KT, Abney CR, Jung MP, Tattersall GJ. Staying warm is not always the norm: behavioural differences in thermoregulation of two snake species. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2021-0135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Thermal biology research compares field with laboratory data to elucidate the evolution of temperature-sensitive traits in ectotherms. The hidden challenge of many of these studies is discerning whether animals actively thermoregulate, since motivation is not typically assessed. By studying the behaviours involved in thermoregulation, we can better understand the mechanisms underlying body temperature control. Using an integrative approach, we assessed the thermoregulatory and thermotactic behaviours of two sympatric snake species with contrasting life histories: the generalist Eastern Garter Snake (Thamnophis sirtalis sirtalis ( Linnaeus, 1758 )) and the semi-fossorial Northern Red-bellied Snake (Storeria occipitomaculata occipitomaculata ( Storer, 1839 )). We expected that thermoregulatory behaviours would be optimized based on life history, in that T. s. sirtalis would show higher evidence for thermally oriented behaviours than S. o. occipitomaculata due to its active nature. Thamnophis sirtalis sirtalis actively thermoregulated, had higher thermal preferences (29.4 ± 2.5 vs. 25.3 ± 3.6 °C), and was more active than S. o. occipitomaculata, which showed relatively low evidence for thermotaxis. Our results build on the notion that evaluating movement patterns and rostral orientation towards a heat source can help ascertain whether animals make thermally motivated choices. Our data provide insight into the thermoregulatory strategies used by snakes with different life histories and maximize the information provided by behavioural thermoregulation experiments.
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Affiliation(s)
- Danilo Giacometti
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
- Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Paulo, Diadema, 09972-270, Brazil
| | - Katharine T. Yagi
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Curtis R. Abney
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Matthew P. Jung
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Glenn J. Tattersall
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
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18
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Currylow AF, Collier MAM, Hanslowe EB, Falk BG, Cade BS, Moy SE, Grajal‐Puche A, Ridgley FN, Reed RN, Yackel Adams AA. Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA. Ecosphere 2021. [DOI: 10.1002/ecs2.3579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Andrea F. Currylow
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Michelle A. M. Collier
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Emma B. Hanslowe
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Bryan G. Falk
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Brian S. Cade
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
| | - Sarah E. Moy
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Alejandro Grajal‐Puche
- U.S. Geological Survey South Florida Field Station Fort Collins Science Center 40001 SR 9336 Homestead Florida 33034 USA
| | - Frank N. Ridgley
- Conservation and Research Department Zoo Miami 12400 SW 152nd Street Miami Florida 33177 USA
| | - Robert N. Reed
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
| | - Amy A. Yackel Adams
- U.S. Geological Survey Fort Collins Science Center 2150 Centre Avenue Building C Fort Collins Colorado 80526 USA
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19
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Madelaire CB, Zena LA, Dillon D, Silva DP, Hunt KE, Loren Buck C, Bícego KC, Gomes FR. Who rules over immunology? Sseasonal variation in body temperature,, steroid hormones, and immune variables in a tegu lizard. Integr Comp Biol 2021; 61:1867-1880. [PMID: 34022037 DOI: 10.1093/icb/icab093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multiple factors can influence the immune response of ectothermic vertebrates, including body temperature, gonadal steroids, and seasonality, in ways that are thought to reflect trade-offs between energetic investment in immunity vs. reproduction. Hibernating tegu lizards (Salvator merianae) are a unique model to investigate how immunocompetence might be influenced by different factors during their annual cycle. We assessed immunological measures (plasma bacterial killing ability, total and differential leukocyte count), plasma hormone levels (testosterone in males, estradiol and progesterone in females, and corticosterone in both sexes), body temperature, and body condition from adult tegus during each stage of their annual cycle: reproduction, post-reproduction/preparation for hibernation, and hibernation. Our hypothesis that immune traits present higher values during the reproductive phase, and a sharp decrease during hibernation, was partially supported. Immune variables did not change between life history stages, except for total number of leukocytes, which was higher at the beginning of the reproductive season (September) in both males and females. Average body temperature of the week prior to sampling was positively correlated with number of eosinophils, basophils, monocytes and azurophils, corroborating other studies showing that when animals maintain a high Tb, there is an increase in immune activity. Surprisingly, no clear relationship between immune traits and gonadal steroids or corticosterone levels was observed, even when including life history stage in the model. When gonadal hormones peaked in males and females, heterophil:lymphocyte ratio (which often elevates during physiological stress) also increased. Additionally, we did not observe any trade-off between reproduction and immunity traits, sex differences in immune traits or a correlation between body condition and immune response. Our results suggest that variation in patterns of immune response and correlations with body condition and hormone secretion across the year can depend upon the specific hormone and immune trait, and that experienced Tb is an important variable determining immune response in ectotherms.
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Affiliation(s)
- Carla B Madelaire
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA.,Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil
| | - Lucas A Zena
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA.,Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil.,Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - Diego P Silva
- Smithsonian-Mason School of Conservation & George Mason University, 1500 Remount Rd, Front Royal, VA, 22630, USA
| | - Kathleen E Hunt
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil
| | - Fernando R Gomes
- Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil
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20
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Hot and covered: how dragons face the heat and thermoregulate. J Comp Physiol B 2021; 191:545-552. [PMID: 33598786 DOI: 10.1007/s00360-020-01332-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 11/16/2020] [Accepted: 11/29/2020] [Indexed: 01/21/2023]
Abstract
Regulating body temperature is a critical function for many animals. Ectotherms use multiple thermoregulatory behaviours, including habitat selection, sun-shade shuttling, posture, orientation, gaping, and panting. According to thermoregulatory control theory, gaping and postural behaviours should act in coordination with microhabitat selection, providing a fine-tuned counterbalance to more costly behaviours. However, gaping and panting have also been considered indicators of stress in lizards, which would counter a homeostatic thermoregulatory interpretation, especially during expression of voluntary behaviours. Careful adjustments in rostral orientation toward warmth have been observed in bearded dragons, analogous to well-described solar gain and solar avoidance postures in the wild. Little is known about the sensory drivers of these behaviours. Although skin temperature changes faster than core, it is not uniform across the body, and is subject to evaporative cooling, and thus could be crucial to directing behavioural thermoregulatory decision making. To examine the subtle coordination between thermoregulatory behaviours, and to test if inhibiting gaping would lead to thermoregulatory compensatory behaviours, bearded dragon lizards (Pogona vitticeps) were allowed to behaviourally thermoregulate, while their ability to show spontaneous gaping behaviour was disrupted non-pharmacologically. Gaping acted in concert with thermoregulatory behaviours, although at lower rates than predicted from earlier steady-state models, suggesting that respiratory cooling mechanisms are perceived as costly. Bearded dragons enhanced their rostral orientation to heat when gaping was inhibited, while reducing their selected temperatures in a thermal gradient. Combined, these observations indicate the presence of coordination between these various thermoregulatory behaviours.
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21
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Goetz SM, Steen DA, Miller MA, Guyer C, Kottwitz J, Roberts JF, Blankenship E, Pearson PR, Warner DA, Reed RN. Argentine Black and White Tegu (Salvator merianae) can survive the winter under semi-natural conditions well beyond their current invasive range. PLoS One 2021; 16:e0245877. [PMID: 33690637 PMCID: PMC7946314 DOI: 10.1371/journal.pone.0245877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 01/09/2021] [Indexed: 11/19/2022] Open
Abstract
The Argentine Black and White Tegu (Salvator merianae, formerly Tupinambis merianae) is a large lizard from South America. Now established and invasive in southern Florida, and it poses threats to populations of many native species. Models suggest much of the southern United States may contain suitable temperature regimes for this species, yet there is considerable uncertainty regarding either the potential for range expansion northward out of tropical and subtropical zones or the potential for the species establishing elsewhere following additional independent introductions. We evaluated survival, body temperature, duration and timing of winter dormancy, and health of wild-caught tegus from southern Florida held in semi-natural enclosures for over a year in Auburn, Alabama (> 900 km northwest of capture location). Nine of twelve lizards emerged from winter dormancy and seven survived the greater-than-one-year duration of the study. Average length of dormancy (176 d) was greater than that reported in the native range or for invasive populations in southern Florida and females remained dormant longer than males. Tegus grew rapidly throughout the study and the presence of sperm in the testes of males and previtellogenic or early vitellogenic follicles in female ovaries at the end of our study suggest the animals would have been capable of reproduction the following spring. The survival and overall health of the majority of adult tegus in our study suggests weather and climate patterns are unlikely to prevent survival following introduction in many areas of the United States far from their current invasive range.
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Affiliation(s)
- Scott M. Goetz
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America
- * E-mail:
| | - David A. Steen
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Gainesville, Florida, United States of America
| | - Melissa A. Miller
- Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center, University of Florida, Davie, Florida, United States of America
| | - Craig Guyer
- Department of Biological Sciences, College of Sciences and Mathematics, Auburn University, Auburn, Alabama, United States of America
| | - Jack Kottwitz
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - John F. Roberts
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Emmett Blankenship
- All Pets Emergency and Referral Center, Alpharetta, Georgia, United States of America
| | - Phillip R. Pearson
- Centre for Conservation, Ecology, and Genetics, Institute for Applied Ecology, University of Canberra, Bruce, Australian Capital City, Australia
| | - Daniel A. Warner
- Department of Biological Sciences, College of Sciences and Mathematics, Auburn University, Auburn, Alabama, United States of America
| | - Robert N. Reed
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, United States of America
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22
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Discovery of a phylogenetically distinct poxvirus in diseased Crocodilurus amazonicus (family Teiidae). Arch Virol 2021; 166:1183-1191. [PMID: 33580379 PMCID: PMC7952365 DOI: 10.1007/s00705-021-04975-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/18/2020] [Indexed: 11/03/2022]
Abstract
A novel poxvirus was discovered in Crocodilurus amazonicus (Teiidae) presenting with a debilitating skin disease. The generated first genome sequence of a reptilian poxvirus revealed the closest phylogenetic relationship to avipoxviruses, highlighting potential virus exchanges between avian and reptilian species.
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23
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Jastroch M, Polymeropoulos ET, Gaudry MJ. Pros and cons for the evidence of adaptive non-shivering thermogenesis in marsupials. J Comp Physiol B 2021; 191:1085-1095. [PMID: 33860348 PMCID: PMC8572181 DOI: 10.1007/s00360-021-01362-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/05/2021] [Accepted: 02/22/2021] [Indexed: 01/11/2023]
Abstract
The thermogenic mechanisms supporting endothermy are still not fully understood in all major mammalian subgroups. In placental mammals, brown adipose tissue currently represents the most accepted source of adaptive non-shivering thermogenesis. Its mitochondrial protein UCP1 (uncoupling protein 1) catalyzes heat production, but the conservation of this mechanism is unclear in non-placental mammals and lost in some placentals. Here, we review the evidence for and against adaptive non-shivering thermogenesis in marsupials, which diverged from placentals about 120-160 million years ago. We critically discuss potential mechanisms that may be involved in the heat-generating process among marsupials.
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Affiliation(s)
- Martin Jastroch
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Elias T. Polymeropoulos
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, TAS 7001 Australia
| | - Michael J. Gaudry
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
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Filogonio R, Orsolini KF, Oda GM, Malte H, Leite CAC. Baroreflex gain and time of pressure decay at different body temperatures in the tegu lizard, Salvator merianae. PLoS One 2020; 15:e0242346. [PMID: 33227002 PMCID: PMC7682859 DOI: 10.1371/journal.pone.0242346] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/01/2020] [Indexed: 12/20/2022] Open
Abstract
Ectotherms may experience large body temperature (Tb) variations. Higher Tb have been reported to increase baroreflex sensitivity in ectotherm tetrapods. At lower Tb, pulse interval (PI) increases and diastolic pressure decays for longer, possibly resulting in lower end-diastolic pressures and mean arterial pressures (Pm). Additionally, compensatory baroreflex-related heart rate modulation (i.e. the cardiac branch of the baroreflex response) is delayed due to increased PI. Thus, low Tb is potentially detrimental, leading to cardiovascular malfunctioning. This raises the question on how Pm is regulated in such an adverse condition. We investigated the baroreflex compensations that enables tegu lizards, Salvator merianae, to maintain blood pressure homeostasis in a wide Tb range. Lizards had their femoral artery cannulated and pressure signals recorded at 15°C, 25°C and 35°C. We used the sequence method to analyse the heart rate baroreflex-related corrections to spontaneous pressure fluctuations at each temperature. Vascular adjustments (i.e. the peripheral branch) were assessed by calculating the time constant for arterial pressure decay (τ)—resultant from the action of both vascular resistance and compliance—by fitting the diastolic pressure descent to the two-element Windkessel equation. We observed that at lower Tb, lizards increased baroreflex gain at the operating point (Gop) and τ, indicating that the diastolic pressure decays at a slower rate. Gop normalized to Pm and PI, as well as the ratio τ/PI, did not change, indicating that both baroreflex gain and rate of pressure decay are adjusted according to PI lengthening. Consequently, pressure parameters and the oscillatory power fraction (an index of wasted cardiac energy) were unaltered by Tb, indicating that both Gop and τ modulation are crucial for cardiovascular homeostasis.
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Affiliation(s)
- Renato Filogonio
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
- * E-mail:
| | - Karina F. Orsolini
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
| | - Gustavo M. Oda
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
| | - Hans Malte
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus C, Denmark
| | - Cléo A. C. Leite
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, São Paulo, Brazil
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25
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Comparative Perspectives that Challenge Brain Warming as the Primary Function of REM Sleep. iScience 2020; 23:101696. [PMID: 33196022 PMCID: PMC7644584 DOI: 10.1016/j.isci.2020.101696] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/17/2020] [Accepted: 10/14/2020] [Indexed: 01/04/2023] Open
Abstract
Rapid eye movement (REM) sleep is a paradoxical state of wake-like brain activity occurring after non-REM (NREM) sleep in mammals and birds. In mammals, brain cooling during NREM sleep is followed by warming during REM sleep, potentially preparing the brain to perform adaptively upon awakening. If brain warming is the primary function of REM sleep, then it should occur in other animals with similar states. We measured cortical temperature in pigeons and bearded dragons, lizards that exhibit NREM-like sleep and REM-like sleep with brain activity resembling wakefulness. In pigeons, cortical temperature decreased during NREM sleep and increased during REM sleep. However, brain temperature did not increase when dragons switched from NREM-like to REM-like sleep. Our findings indicate that brain warming is not a universal outcome of sleep states characterized by wake-like activity, challenging the hypothesis that their primary function is to warm the brain in preparation for wakefulness. In many mammals, the brain cools during non-REM sleep and warms during REM sleep Pigeons exhibit similar changes in cortical temperature during non-REM and REM sleep Brain temperature does not increase during REM-like sleep in bearded dragon lizards Brain warming is not a universal outcome of sleep states with wake-like brain activity
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26
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Bodensteiner BL, Agudelo‐Cantero GA, Arietta AZA, Gunderson AR, Muñoz MM, Refsnider JM, Gangloff EJ. Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians? JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:173-194. [DOI: 10.1002/jez.2414] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/17/2020] [Accepted: 09/04/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Brooke L. Bodensteiner
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut USA
| | - Gustavo A. Agudelo‐Cantero
- Department of Physiology, Institute of Biosciences University of São Paulo São Paulo Brazil
- Department of Biology ‐ Genetics, Ecology, and Evolution Aarhus University Aarhus Denmark
| | | | - Alex R. Gunderson
- Department of Ecology and Evolutionary Biology Tulane University New Orleans Louisiana USA
| | - Martha M. Muñoz
- Department of Ecology and Evolutionary Biology Yale University New Haven Connecticut USA
| | | | - Eric J. Gangloff
- Department of Zoology Ohio Wesleyan University Delaware Ohio USA
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27
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Tsai HY, Rubenstein DR, Chen BF, Liu M, Chan SF, Chen DP, Sun SJ, Yuan TN, Shen SF. Antagonistic effects of intraspecific cooperation and interspecific competition on thermal performance. eLife 2020; 9:57022. [PMID: 32807299 PMCID: PMC7442485 DOI: 10.7554/elife.57022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/28/2020] [Indexed: 01/03/2023] Open
Abstract
Understanding how climate-mediated biotic interactions shape thermal niche width is critical in an era of global change. Yet, most previous work on thermal niches has ignored detailed mechanistic information about the relationship between temperature and organismal performance, which can be described by a thermal performance curve. Here, we develop a model that predicts the width of thermal performance curves will be narrower in the presence of interspecific competitors, causing a species' optimal breeding temperature to diverge from that of its competitor. We test this prediction in the Asian burying beetle Nicrophorus nepalensis, confirming that the divergence in actual and optimal breeding temperatures is the result of competition with their primary competitor, blowflies. However, we further show that intraspecific cooperation enables beetles to outcompete blowflies by recovering their optimal breeding temperature. Ultimately, linking abiotic factors and biotic interactions on niche width will be critical for understanding species-specific responses to climate change.
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Affiliation(s)
- Hsiang-Yu Tsai
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.,Institute of Ecology and Evolutionary Biology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, United States.,Center for Integrative Animal Behavior, Columbia University, New York, United States
| | - Bo-Fei Chen
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Mark Liu
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Shih-Fan Chan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - De-Pei Chen
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.,Institute of Ecology and Evolutionary Biology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Syuan-Jyun Sun
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Tzu-Neng Yuan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Sheng-Feng Shen
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.,Institute of Ecology and Evolutionary Biology, College of Life Science, National Taiwan University, Taipei, Taiwan
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28
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Farmer CG. Parental Care, Destabilizing Selection, and the Evolution of Tetrapod Endothermy. Physiology (Bethesda) 2020; 35:160-176. [PMID: 32293231 DOI: 10.1152/physiol.00058.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Parental care has evolved convergently an extraordinary number of times among tetrapods that reproduce terrestrially, suggesting strong positive selection for this behavior in the terrestrial environment. This review speculates that destabilizing selection on parental care, and especially embryo incubation, drove the convergent evolution of many tetrapod traits, including endothermy.
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Affiliation(s)
- C G Farmer
- Trinity College Dublin, Dublin, Ireland; and University of Utah, Salt Lake City, Utah
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29
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Seebacher F. Is Endothermy an Evolutionary By-Product? Trends Ecol Evol 2020; 35:503-511. [PMID: 32396817 DOI: 10.1016/j.tree.2020.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/29/2020] [Accepted: 02/11/2020] [Indexed: 12/21/2022]
Abstract
Endothermy alters the energetic relationships between organisms and their environment and thereby influences fundamental niches. Endothermy is closely tied to energy metabolism. Regulation of energy balance is indispensable for all life and regulatory pathways increase in complexity from bacteria to vertebrates. Increasing complexity of metabolic networks also increase the probability for endothermic phenotypes to appear. Adaptive arguments are problematic epistemologically because the regulatory mechanisms enabling endothermy have not evolved for the 'purpose' of endothermy and the utility of current traits is likely to have changed over evolutionary time. It is most parsimonious to view endothermy as the evolutionary by-product of energy balance regulation rather than as an adaptation and interpret its evolution in the context of metabolic networks.
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Affiliation(s)
- Frank Seebacher
- School of Life and Environmental Sciences, Heydon-Laurence Building A08, University of Sydney, NSW 2006, Australia.
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30
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Wu Y, Wang H. Convergent evolution of bird-mammal shared characteristics for adapting to nocturnality. Proc Biol Sci 2020; 286:20182185. [PMID: 30963837 DOI: 10.1098/rspb.2018.2185] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The diapsid lineage (birds) and synapsid lineage (mammals), share a suite of functionally similar characteristics (e.g. endothermy) that are considered to be a result of their convergent evolution, but the candidate selections leading to this convergent evolution are still under debate. Here, we used a newly developed molecular phyloecological approach to reconstruct the diel activity pattern of the common ancestors of living birds. Our results strongly suggest that they had adaptations to nocturnality during their early evolution, which is remarkably similar to that of ancestral mammals. Given their similar adaptation to nocturnality, we propose that the shared traits in birds and mammals may have partly evolved as a result of the convergent evolution of their early ancestors adapting to ecological factors (e.g. low ambient temperature) associated with nocturnality. Finally, a conceptually unifying ecological model on the evolution of endothermy in diverse organisms with an emphasis on low ambient temperature is proposed. We reason that endothermy may evolve as an adaptive strategy to enable organisms to effectively implement various life-cycle activities under relatively low-temperature environments. In particular, a habitat shift from high-temperature to relatively low-temperature environments is identified as a common factor underlying the evolution of endothermy.
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Affiliation(s)
- Yonghua Wu
- 1 School of Life Sciences, Northeast Normal University , 5268 Renmin Street, Changchun 130024 , People's Republic of China.,2 Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University , 2555 Jingyue Street, Changchun 130117 , People's Republic of China
| | - Haifeng Wang
- 3 Department of Bioengineering, Stanford University , Stanford, CA 94305 , USA
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31
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Legendre LJ, Davesne D. The evolution of mechanisms involved in vertebrate endothermy. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190136. [PMID: 31928191 DOI: 10.1098/rstb.2019.0136] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Endothermy, i.e. the endogenous production of metabolic heat, has evolved multiple times among vertebrates, and several strategies of heat production have been studied extensively by physiologists over the course of the twentieth century. The independent acquisition of endothermy by mammals and birds has been the subject of many hypotheses regarding their origin and associated evolutionary constraints. Many groups of vertebrates, however, are thought to possess other mechanisms of heat production, and alternative ways to regulate thermogenesis that are not always considered in the palaeontological literature. Here, we perform a review of the mechanisms involved in heat production, with a focus on cellular and molecular mechanisms, in a phylogenetic context encompassing the entire vertebrate diversity. We show that endothermy in mammals and birds is not as well defined as commonly assumed by evolutionary biologists and consists of a vast array of physiological strategies, many of which are currently unknown. We also describe strategies found in other vertebrates, which may not always be considered endothermy, but nonetheless correspond to a process of active thermogenesis. We conclude that endothermy is a highly plastic character in vertebrates and provides a guideline on terminology and occurrences of the different types of heat production in vertebrate evolution. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Lucas J Legendre
- Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
| | - Donald Davesne
- Department of Earth Sciences, University of Oxford, Oxford, UK
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32
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Bal NC, Periasamy M. Uncoupling of sarcoendoplasmic reticulum calcium ATPase pump activity by sarcolipin as the basis for muscle non-shivering thermogenesis. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190135. [PMID: 31928193 DOI: 10.1098/rstb.2019.0135] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Thermogenesis in endotherms relies on both shivering and non-shivering thermogenesis (NST). The role of brown adipose tissue (BAT) in NST is well recognized, but the role of muscle-based NST has been contested. However, recent studies have provided substantial evidence for the importance of muscle-based NST in mammals. This review focuses primarily on the role of sarcoplasmic reticulum (SR) Ca2+-cycling in muscle NST; specifically, it will discuss recent data showing how uncoupling of sarcoendoplasmic reticulum calcium ATPase (SERCA) (inhibition of Ca2+ transport but not ATP hydrolysis) by sarcolipin (SLN) results in futile SERCA pump activity, increased ATP hydrolysis and heat production contributing to muscle NST. It will also critically examine how activation of muscle NST can be an important factor in regulating metabolic rate and whole-body energy homeostasis. In this regard, SLN has emerged as a powerful signalling molecule to promote mitochondrial biogenesis and oxidative metabolism in muscle. Furthermore, we will discuss the functional interplay between BAT and muscle, especially with respect to how reduced BAT function in mammals could be compensated by muscle-based NST. Based on the existing data, we argue that SLN-mediated thermogenesis is an integral part of muscle NST and that muscle NST potentially contributed to the evolution of endothermy within the vertebrate clade. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Naresh C Bal
- KIIT School of Biotechnology, KIIT University, Bhubaneswar, Odisha 751021, India
| | - Muthu Periasamy
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
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33
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Abstract
Physiology is a functional branch of the biological sciences, searching for general rules by which explanatory hypotheses are tested using experimental procedures, whereas palaeontology is a historical science dealing with the study of unique events where conclusions are drawn from congruence among independent lines of evidence. Vertebrate palaeophysiology bridges these disciplines by using experimental data obtained from extant organisms to infer physiological traits of extinct ones and to reconstruct how they evolved. The goal of this theme issue is to understand functional innovations imprinted on modern vertebrate clades, and how to infer (or 'retrodict') physiological capacities in their ancient relatives a posteriori. As such, the present collection of papers deals with different aspects of a rapidly growing field to understand innovations in: phospho-calcic metabolism, acid-base homeostasis, thermometabolism, respiratory physiology, skeletal growth, palaeopathophysiology, genome size and metabolic rate, and it concludes with a historical perspective. Sometimes, the two components (physiological mechanism and palaeobiological inference) are proposed in separate papers. Other times, the two components are integrated in a single paper. In all cases, the approach was comparative, framed in a phylogenetic context, and included rigorous statistical methods that account for evolutionary patterns and processes. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- Jorge Cubo
- Sorbonne Université, MNHN, CNRS, Centre de Recherche en Paléontologie-Paris (CR2P, UMR 7207), 4 Place Jussieu, 75005 Paris, France
| | - Adam K Huttenlocker
- Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, CA, USA
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34
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Zena LA, Dillon D, Hunt KE, Navas CA, Buck CL, Bícego KC. Hormonal correlates of the annual cycle of activity and body temperature in the South-American tegu lizard (Salvator merianae). Gen Comp Endocrinol 2020; 285:113295. [PMID: 31580883 DOI: 10.1016/j.ygcen.2019.113295] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/19/2019] [Accepted: 09/29/2019] [Indexed: 01/29/2023]
Abstract
Life history transitions and hormones are known to interact and influence many aspects of animal physiology and behavior. The South-American tegu lizard (Salvator merianae) exhibits a profound seasonal shift in metabolism and body temperature, characterized by high daily activity during warmer months, including reproductive endothermy in spring, and metabolic suppression during hibernation in winter. This makes S. merianae an interesting subject for studies of interrelationships between endocrinology and seasonal changes in physiology/behavior. We investigated how plasma concentrations of hormones involved in regulation of energy metabolism (thyroid hormones T4 and T3; corticosterone) and reproduction (testosterone in males and estrogen/progesterone in females) correlate with activity and body temperature (Tb) across the annual cycle of captive held S. merianae in semi-natural conditions. In our initial model, thyroid hormones and corticosterone showed a positive relationship with activity and Tb with independent of sex: T3 positively correlated with activity and Tb, while T4 and corticosterone correlated positively with changes in Tb only. This suggests that thyroid hormones and glucocorticoids may be involved in metabolic transitions of annual cycle events. When accounting for sex-steroid hormones, our sex separated models showed a positive relationship between testosterone and Tb in males and progesterone and activity in females. Coupling seasonal endocrine measures with activity and Tb may expand our understanding of the relationship between animal's physiology and its environment. Manipulative experiments are required in order to unveil the directionality of influences existing among abiotic factors and the hormonal signaling of annual cyclicity in physiology/behavior.
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Affiliation(s)
- Lucas A Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, Fairfax, VA, USA
| | - Carlos A Navas
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900 Jaboticabal, São Paulo, Brazil.
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35
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Burggren W, Filogonio R, Wang T. Cardiovascular shunting in vertebrates: a practical integration of competing hypotheses. Biol Rev Camb Philos Soc 2019; 95:449-471. [PMID: 31859458 DOI: 10.1111/brv.12572] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 10/30/2019] [Accepted: 11/07/2019] [Indexed: 12/20/2022]
Abstract
This review explores the long-standing question: 'Why do cardiovascular shunts occur?' An historical perspective is provided on previous research into cardiac shunts in vertebrates that continues to shape current views. Cardiac shunts and when they occur is then described for vertebrates. Nearly 20 different functional reasons have been proposed as specific causes of shunts, ranging from energy conservation to improved gas exchange, and including a plethora of functions related to thermoregulation, digestion and haemodynamics. It has even been suggested that shunts are merely an evolutionary or developmental relic. Having considered the various hypotheses involving cardiovascular shunting in vertebrates, this review then takes a non-traditional approach. Rather than attempting to identify the single 'correct' reason for the occurrence of shunts, we advance a more holistic, integrative approach that embraces multiple, non-exclusive suites of proposed causes for shunts, and indicates how these varied functions might at least co-exist, if not actually support each other as shunts serve multiple, concurrent physiological functions. It is argued that deposing the 'monolithic' view of shunting leads to a more nuanced view of vertebrate cardiovascular systems. This review concludes by suggesting new paradigms for testing the function(s) of shunts, including experimentally placing organ systems into conflict in terms of their perfusion needs, reducing sources of variation in physiological experiments, measuring possible compensatory responses to shunt ablation, moving experiments from the laboratory to the field, and using cladistics-related approaches in the choice of experimental animals.
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Affiliation(s)
- Warren Burggren
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX, 76203-5220, U.S.A
| | - Renato Filogonio
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus C, 8000, Denmark.,Aarhus Institute of Advanced Sciences (AIAS), Aarhus University, Aarhus C, 8000, Denmark
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36
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Filogonio R, Wang T, Abe AS, Leite CA. Cooling and Warming Rates are Unaffected by Autonomic Vascular Control in the South American Rattlesnake (Crotalus durissus). SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2019. [DOI: 10.2994/sajh-d-18-00013.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Renato Filogonio
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Augusto S. Abe
- Department of Zoology, State University of São Paulo, Rio Claro, SP, Brazil
| | - Cléo A.C. Leite
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil
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37
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Pettit TV, Pettit RJ, Durso AM, French SS. Investment of both essential fatty and amino acids to immunity varies depending on reproductive stage. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 331:552-561. [PMID: 31625280 DOI: 10.1002/jez.2324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 08/10/2019] [Accepted: 09/08/2019] [Indexed: 12/29/2022]
Abstract
Trade-offs among the key life-history traits of reproduction and immunity have been widely documented. However, the currency in use is not well-understood. We investigated how reproducing female side-blotched lizards, Uta stansburiana, allocate lipids versus proteins when given an immune challenge. We tested whether lizards would invest more in reproduction or immunity depending on reproductive stage. Females were given stable isotopes (15 N-leucine and 13 C-1-palmitic acid), maintained on a regular diet and given either a cutaneous biopsy or a sham biopsy (control). Stable isotopes were monitored and analyzed in feces and uric acid, skin biopsies, eggs, and toe clips. We found that lizards deposited both proteins and lipids into their healing wounds (immune-challenged), skin (control), and eggs (all) and that catabolism of proteins exceeded incorporation into tissue during wound-healing. Specifically, we found that healed biopsies of wounded animals had more leucine and palmitic acid than the nonregrown skin biopsies taken from unwounded control animals. Earlier in reproduction, lizards invested relatively more labeled proteins into healing their wound tissue, but not into unwounded skin of control animals. Thus, reproduction is sometimes favored over self-maintenance, but only in later reproductive stages. Finally, we documented positive relationships among the amount of palmitic acid deposited in the eggs, the amount of food eaten, and the amount of palmitic acid excreted, suggesting higher turnover rates of lipids in lizards investing highly in their eggs.
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Affiliation(s)
- Taylor V Pettit
- Department of Biology and the Ecology Center, Utah State University, Logan, Utah
| | - R John Pettit
- Department of Biology and the Ecology Center, Utah State University, Logan, Utah
| | - Andrew M Durso
- Department of Biology and the Ecology Center, Utah State University, Logan, Utah
| | - Susannah S French
- Department of Biology and the Ecology Center, Utah State University, Logan, Utah
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38
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Thermal regime effects on the resting metabolic rate of rattlesnakes depend on temperature range. J Therm Biol 2019; 83:199-205. [PMID: 31331520 DOI: 10.1016/j.jtherbio.2019.05.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 11/20/2022]
Abstract
While ectothermic organisms often experience considerable circadian variation in body temperature under natural conditions, the study of the effects of temperature on metabolic rates are traditionally based on subjecting animals to constant temperature regimes. Whether data resulting from constant-temperature experiments accurately predicts temperature effects under more natural fluctuating temperature regimes remains uncertain. To address such possibility, we measured the resting metabolic rates of the South American rattlesnakes (Crotalus durissus) under constant and circadian fluctuating thermal regimes in a range of temperatures. Metabolic rates measured at constant 20 °C and 25 °C did not differ from the rates measured at fluctuating regimes with corresponding mean temperatures. However, the difference between thermal regimes increased with temperature, with the metabolic rate measured at constant 30 °C being greater than that measured at the fluctuating thermal regime with corresponding mean temperature. Therefore, our results indicate that thermal regime effects on rattlesnakes' metabolism is dependent on temperature range. Broadly, our results highlight the importance of considering multi-factorial attributes of temperature variation in the exam of its effects over functional traits. Such approach provides a more solid support for inferences about temperature effects on the life history, ecology and conservation of ectothermic organisms.
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39
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Robertson CE, Tattersall GJ, McClelland GB. Development of homeothermic endothermy is delayed in high-altitude native deer mice (Peromyscus maniculatus). Proc Biol Sci 2019; 286:20190841. [PMID: 31337307 DOI: 10.1098/rspb.2019.0841] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Altricial mammals begin to independently thermoregulate during the first few weeks of postnatal development. In wild rodent populations, this is also a time of high mortality (50-95%), making the physiological systems that mature during this period potential targets for selection. High altitude (HA) is a particularly challenging environment for small endotherms owing to unremitting low O2 and ambient temperatures. While superior thermogenic capacities have been demonstrated in adults of some HA species, it is unclear if selection has occurred to survive these unique challenges early in development. We used deer mice (Peromyscus maniculatus) native to high and low altitude (LA), and a strictly LA species (Peromyscus leucopus), raised under common garden conditions, to determine if postnatal onset of endothermy and maturation of brown adipose tissue (BAT) is affected by altitude ancestry. We found that the onset of endothermy corresponds with the maturation and activation of BAT at an equivalent age in LA natives, with 10-day-old pups able to thermoregulate in response to acute cold in both species. However, the onset of endothermy in HA pups was substantially delayed (by approx. 2 days), possibly driven by delayed sympathetic regulation of BAT. We suggest that this delay may be part of an evolved cost-saving measure to allow pups to maintain growth rates under the O2-limited conditions at HA.
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Affiliation(s)
- Cayleih E Robertson
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Glenn J Tattersall
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada L2S 3A1
| | - Grant B McClelland
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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Filogonio R, Orsolini KF, Castro SA, Oda GM, Rocha GC, Tavares D, Abe AS, Leite CAC. Evaluation of the sequence method as a tool to assess spontaneous baroreflex in reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 331:374-381. [DOI: 10.1002/jez.2273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Renato Filogonio
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
| | - Karina F. Orsolini
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
| | - Samanta A. Castro
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
| | - Gustavo M. Oda
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
| | - Gabriella C. Rocha
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
| | - Driele Tavares
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
| | - Augusto S. Abe
- Department of Zoology; State University of São Paulo (UNESP); Rio Claro São Paulo Brazil
| | - Cléo A. C. Leite
- Department of Physiological Sciences; Federal University of São Carlos (UFSCar); São Carlos São Paulo Brazil
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Poelmann RE, Gittenberger-de Groot AC. Development and evolution of the metazoan heart. Dev Dyn 2019; 248:634-656. [PMID: 31063648 PMCID: PMC6767493 DOI: 10.1002/dvdy.45] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 12/19/2022] Open
Abstract
The mechanisms of the evolution and development of the heart in metazoans are highlighted, starting with the evolutionary origin of the contractile cell, supposedly the precursor of cardiomyocytes. The last eukaryotic common ancestor is likely a combination of several cellular organisms containing their specific metabolic pathways and genetic signaling networks. During evolution, these tool kits diversified. Shared parts of these conserved tool kits act in the development and functioning of pumping hearts and open or closed circulations in such diverse species as arthropods, mollusks, and chordates. The genetic tool kits became more complex by gene duplications, addition of epigenetic modifications, influence of environmental factors, incorporation of viral genomes, cardiac changes necessitated by air‐breathing, and many others. We evaluate mechanisms involved in mollusks in the formation of three separate hearts and in arthropods in the formation of a tubular heart. A tubular heart is also present in embryonic stages of chordates, providing the septated four‐chambered heart, in birds and mammals passing through stages with first and second heart fields. The four‐chambered heart permits the formation of high‐pressure systemic and low‐pressure pulmonary circulation in birds and mammals, allowing for high metabolic rates and maintenance of body temperature. Crocodiles also have a (nearly) separated circulation, but their resting temperature conforms with the environment. We argue that endothermic ancestors lost the capacity to elevate their body temperature during evolution, resulting in ectothermic modern crocodilians. Finally, a clinically relevant paragraph reviews the occurrence of congenital cardiac malformations in humans as derailments of signaling pathways during embryonic development. The cardiac regulatory toolkit contains many factors including epigenetic, genetic, viral, hemodynamic, and environmental factors, but also transcriptional activators, repressors, duplicated genes, redundancies and dose‐dependancies. Numerous toolkits regulate mechanisms including cell‐cell interactions, EMT, mitosis patterns, cell migration and differentiation and left/right sidedness involved in the development of endocardial cushions, looping, septum complexes, pharyngeal arch arteries, chamber and valve formation and conduction system. Evolutionary development of the yolk sac circulation likely preceded the advent of endothermy in amniotes. Parallel evolutionary traits regulate the development of contractile pumps in various taxa often in conjunction with the gut, lungs and excretory organs.
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Affiliation(s)
- Robert E Poelmann
- Institute of Biology, Department of Animal Sciences and Health, Leiden University, Leiden, The Netherlands.,Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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Zena LA, Dillon D, Hunt KE, Navas CA, Bícego KC, Buck CL. Seasonal changes in plasma concentrations of the thyroid, glucocorticoid and reproductive hormones in the tegu lizard Salvator merianae. Gen Comp Endocrinol 2019; 273:134-143. [PMID: 29913170 DOI: 10.1016/j.ygcen.2018.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/16/2018] [Accepted: 06/15/2018] [Indexed: 12/21/2022]
Abstract
The tegu lizard Salvator merianae is a large, widely distributed teiid lizard endemic to South America that exhibits annual cycles of high activity during the spring and summer, and hibernation during winter. This pattern of activity and hibernation is accompanied by profound seasonal changes in physiology and behavior, including endothermy during the austral spring. The unusual combination of seasonal endothermy, hibernation and oviparity, in a non-avian, non-mammalian species, makes S. merianae an interesting subject for study of comparative aspects of endocrine regulation of seasonal changes in physiology. In the present study, we first validated commercially available immunoassay kits for quantification of hormone concentrations of the reproductive (testosterone, estradiol and progesterone), adrenal (corticosterone), and thyroid [thyroxine (T4) and triiodothyronine (T3)] axes in plasma of an outdoor, captive adult male and female S. merianae in southeastern Brazil. All assays exhibited parallelism and accuracy with S. merianae plasma. We next assessed patterns of concentration of these hormones across the annual cycle of S. merianae. Testosterone in males and estradiol in females peaked in spring coincident with the peak in reproductive behavior. Progesterone in females was significantly elevated in October coincident with putative ovulation when gravid females build nests. Thyroid hormones, known for regulating energy metabolism, varied seasonally with some sex-dependent differences. T4 gradually increased from an annual nadir during pre-hibernation and hibernation to high concentrations during spring in both sexes. In contrast, T3 did not vary seasonally in males, but females showed a two-fold increase in T3 during the spring reproductive season. T3 may be involved in energy investment during the seasonal production of large clutches of eggs. Corticosterone was significantly elevated during the active season in both sexes, suggesting its involvement in mobilization of energy stores and modulation of behavior (territoriality) and physiology. Ours is the first investigation of concurrent changes in reproductive, thyroid and adrenal hormone concentrations in this endemic and physiologically unique South American lizard. Our findings set the stage for future investigations to determine the extent to which these hormones influence activity and thermoregulation in S. merianae.
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Affiliation(s)
- Lucas A Zena
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil; Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil; National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Brazil.
| | - Danielle Dillon
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Kathleen E Hunt
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA
| | - Carlos A Navas
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, 14884-900, Jaboticabal, São Paulo, Brazil; National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Brazil
| | - C Loren Buck
- Department of Biological Sciences, Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, AZ, USA.
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Graham JL, Bauer CM, Heidinger BJ, Ketterson ED, Greives TJ. Early‐breeding females experience greater telomere loss. Mol Ecol 2019; 28:114-126. [DOI: 10.1111/mec.14952] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 10/12/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Jessica L. Graham
- Department of Biological Sciences North Dakota State University Fargo North Dakota
| | | | - Britt J. Heidinger
- Department of Biological Sciences North Dakota State University Fargo North Dakota
| | | | - Timothy J. Greives
- Department of Biological Sciences North Dakota State University Fargo North Dakota
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Foucart T, Heulin B, Lourdais O. Small changes, big benefits: testing the significance of maternal thermoregulation in a lizard with extended egg retention. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Thomas Foucart
- Station Biologique de Paimpont, UMR 6553 CNRS, Paimpont, France
- Centre d’étude biologique de Chizé CNRS, Villiers en Bois, France
| | - Benoit Heulin
- Station Biologique de Paimpont, UMR 6553 CNRS, Paimpont, France
| | - Olivier Lourdais
- Centre d’étude biologique de Chizé CNRS, Villiers en Bois, France
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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Abstract
While human hibernation would provide many advantages for medical applications and space exploration, the intrinsic risks of the procedure itself, as well as those involved if the procedure were to be misused, need to be assessed. Moreover, the distinctive brain state that is present during a hibernation-like state raises questions regarding the state of consciousness of the subject. Since, in animal studies, the cortical activity of this state differs from that of sleep, coma, or even general anesthesia, and resembles a sort of "slowed wakefulness", it is uncertain whether residual consciousness may still be present. In this review, I will present a brief summary of the literature on hibernation and of the current state of the art in inducing a state of artificial hibernation (synthetic torpor); I will then focus on the brain changes that are observed during hibernation, on how these could modify the neural substrate of consciousness, and on the possible use of hibernation as a model for quantum biology. Finally, some ethical considerations on the use of synthetic torpor technology will be presented.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Piazza di Porta S.Donato, 2, 40126, Bologna, Italy. Tel.: +39 051 2091731; Fax: +39 051 2091737; E-mail:
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Subtropical hibernation in juvenile tegu lizards (Salvator merianae): insights from intestine redox dynamics. Sci Rep 2018; 8:9368. [PMID: 29921981 PMCID: PMC6008456 DOI: 10.1038/s41598-018-27263-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022] Open
Abstract
Juvenile tegu lizards (Salvator merianae) experience gradual and mild temperature changes from autumn to winter in their habitat. This tropical/subtropical reptile enter a state of dormancy, with an 80% reduction in metabolic rate, that remains almost constant during winter. The redox metabolism in non-mammalian vertebrates that hibernate under such distinguished conditions is poorly understood. We analyzed the redox metabolism in the intestine of juvenile tegus during different stages of their first annual cycle. The effect of food deprivation (in spring) was also studied to compare with fasting during hibernation. Both winter dormancy and food deprivation caused decreases in reduced glutathione levels and glutathione transferase activity. While glutathione peroxidase and glutathione transferase activities decreased during winter dormancy, as well as glutathione (GSH) levels, other antioxidant enzymes (catalase, superoxide dismutase and glutathione reductase) remained unchanged. Notably, levels of disulfide glutathione (GSSG) were 2.1-fold higher in late autumn, when animals were in the process of depressing metabolism towards hibernation. This increased “oxidative tonus” could be due to a disruption in NADPH-dependent antioxidant systems. In dormancy, GSSG and lipid hydroperoxides were diminished by 60–70%. The results suggest that the entrance into hibernation is the main challenge for the redox homeostasis in the intestine of juvenile tegus.
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Garland T, Albuquerque RL. Locomotion, Energetics, Performance, and Behavior: A Mammalian Perspective on Lizards, and Vice Versa. Integr Comp Biol 2018; 57:252-266. [PMID: 28859413 DOI: 10.1093/icb/icx059] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
SYNOPSIS Animals are constrained by their abilities and by interactions with environmental factors, such as low ambient temperatures. These constraints range from physical impossibilities to energetic inefficiencies, and may entail trade-offs. Some of the constraints related to locomotion and activity metabolism can be illustrated through allometric comparisons of mammals and lizards, as representative terrestrial vertebrate endotherms and ectotherms, respectively, because these lineages differ greatly in aerobic metabolic capacities, resting energetic costs, and thermoregulatory patterns. Allometric comparisons are both useful and unavoidable, but "outlier" species (unusual for their clade) can also inform evolutionary scenarios, as they help indicate extremes of possible adaptation within mammalian and saurian levels of organization. We compared mammals and lizards for standard metabolic rate (SMR), maximal oxygen consumption during forced exercise (VO2max), net (incremental) cost of transport (NCT), maximal aerobic speed (MAS), daily movement distance (DMD), daily energy expenditure (DEE) during the active season, and the ecological cost of transport (ECT = percentage of DEE attributable to locomotion). (Snakes were excluded because their limbless locomotion has no counterpart in terrestrial mammals.) We only considered lizard SMR, VO2max, NCT, MAS, and sprint speed data if measured at 35-40 °C. On average, MAS is ∼7.4-fold higher in mammals, whereas SMR and VO2max are ∼6-fold greater, but values for all three of these traits overlap (or almost overlap) between mammals and lizards, a fact that has not previously been appreciated. Previous studies show that sprint speeds are similar for smaller mammals and lizards, but at larger sizes lizards are not as fast as some mammals. Mammals move ∼6-fold further each day than lizards, and DMD is by far the most variable trait considered here, but their NCT is similar. Mammals exceed lizards by ∼11.4-fold for DEE. On average for both lineages, the ECT is surprisingly low, somewhat higher for lizards, and positively allometric. If a lizard and mammal of 100 g body mass were both to move their entire DMD at their MAS, they could do so in ∼21 and 17 min, respectively, thus de-emphasizing the possible importance of time constraints. We conclude that ecological-energetic constraints related to locomotion are relatively more likely to occur in large, carnivorous lizards. Overall, our comparisons support the idea that the (gradual) evolution of mammalian endothermy did not necessarily require major changes in locomotor energetics, performance, or associated behaviors. Instead, we speculate that the evolution of thermoregulatory responses to low temperatures (e.g., shivering) may have been a key and "difficult" step in this transition.
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Affiliation(s)
- Theodore Garland
- Department of Biology, University of California, Riverside, CA 92506, USA
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Alexander GJ. Reproductive biology and maternal care of neonates in southern African python (Python natalensis). J Zool (1987) 2018. [DOI: 10.1111/jzo.12554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- G. J. Alexander
- School of Animal, Plant and Environmental Sciences; University of the Witwatersrand; Johannesburg South Africa
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Myhrvold NP. Response to formal comment on Myhrvold (2016) submitted by Griebeler and Werner (2017). PLoS One 2018; 13:e0192912. [PMID: 29489880 PMCID: PMC5831047 DOI: 10.1371/journal.pone.0192912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/20/2018] [Indexed: 11/19/2022] Open
Abstract
Griebeler and Werner offer a formal comment on Myhrvold, 2016 defending the conclusions of Werner and Griebeler, 2014. Although the comment criticizes several aspects of methodology in Myhrvold, 2016, all three papers concur on a key conclusion: the metabolism of extant endotherms and ectotherms cannot be reliably classified using growth-rate allometry, because the growth rates of extant endotherms and ectotherms overlap. A key point of disagreement is that the 2014 paper concluded that despite this general case, one can nevertheless classify dinosaurs as ectotherms from their growth rate allometry. The 2014 conclusion is based on two factors: the assertion (made without any supporting arguments) that the comparison with dinosaurs must be restricted only to extant sauropsids, ignoring other vertebrate groups, and that extant sauropsid endotherm and ectotherm growth rates in a data set studied in the 2014 work do not overlap. The Griebeler and Werner formal comment presents their first arguments in support of the restriction proposition. In this response I show that this restriction is unsupported by established principles of phylogenetic comparison. In addition, I show that the data set studied in their 2014 work does show overlap, and that this is visible in one of its figures. I explain how either point effectively invalidates the conclusion of their 2014 paper. I also address the other methodological criticisms of Myhrvold 2016, and find them unsupported.
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Jones MEH, Gröning F, Dutel H, Sharp A, Fagan MJ, Evans SE. The biomechanical role of the chondrocranium and sutures in a lizard cranium. J R Soc Interface 2017; 14:20170637. [PMID: 29263126 PMCID: PMC5746569 DOI: 10.1098/rsif.2017.0637] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/28/2017] [Indexed: 11/30/2022] Open
Abstract
The role of soft tissues in skull biomechanics remains poorly understood. Not least, the chondrocranium, the portion of the braincase which persists as cartilage with varying degrees of mineralization. It also remains commonplace to overlook the biomechanical role of sutures despite evidence that they alter strain distribution. Here, we examine the role of both the sutures and the chondrocranium in the South American tegu lizard Salvator merianae We use multi-body dynamics analysis (MDA) to provide realistic loading conditions for anterior and posterior unilateral biting and a detailed finite element model to examine strain magnitude and distribution. We find that strains within the chondrocranium are greatest during anterior biting and are primarily tensile; also that strain within the cranium is not greatly reduced by the presence of the chondrocranium unless it is given the same material properties as bone. This result contradicts previous suggestions that the anterior portion (the nasal septum) acts as a supporting structure. Inclusion of sutures to the cranium model not only increases overall strain magnitudes but also leads to a more complex distribution of tension and compression rather than that of a beam under sagittal bending.
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Affiliation(s)
- Marc E H Jones
- School of Biological Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
- South Australian Museum, North Terrace, Adelaide, South Australia 5001, Australia
| | - Flora Gröning
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Hugo Dutel
- School of Engineering and Computer Science, Medical and Biological Engineering Research Group, University of Hull, Hull HU6 7RX, UK
| | - Alana Sharp
- Research Department of Cell and Developmental Biology, UCL, University College London, Anatomy Building, Gower Street, London WCIE 6BT, UK
| | - Michael J Fagan
- School of Engineering and Computer Science, Medical and Biological Engineering Research Group, University of Hull, Hull HU6 7RX, UK
| | - Susan E Evans
- Research Department of Cell and Developmental Biology, UCL, University College London, Anatomy Building, Gower Street, London WCIE 6BT, UK
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