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Souchet J, Josserand A, Darnet E, Le Chevalier H, Trochet A, Bertrand R, Calvez O, Martinez-Silvestre A, Guillaume O, Mossoll-Torres M, Pottier G, Philippe H, Aubret F, Gangloff EJ. Embryonic and juvenile snakes (Natrix maura, Linnaeus 1758) compensate for high elevation hypoxia via shifts in cardiovascular physiology and metabolism. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:1102-1115. [PMID: 37723946 DOI: 10.1002/jez.2756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 07/30/2023] [Accepted: 08/30/2023] [Indexed: 09/20/2023]
Abstract
The colonization of novel environments requires a favorable response to conditions never, or rarely, encountered in recent evolutionary history. For example, populations colonizing upslope habitats must cope with lower atmospheric pressure at elevation, and thus reduced oxygen availability. The embryo stage in oviparous organisms is particularly susceptible, given its lack of mobility and limited gas exchange via diffusion through the eggshell and membranes. Especially little is known about responses of Lepidosaurian reptiles to reduced oxygen availability. To test the role of physiological plasticity during early development in response to high elevation hypoxia, we performed a transplant experiment with the viperine snake (Natrix maura, Linnaeus 1758). We maintained gravid females originating from low elevation populations (432 m above sea level [ASL]-normoxia) at both the elevation of origin and high elevation (2877 m ASL-extreme high elevation hypoxia; approximately 72% oxygen availability relative to sea level), then incubated egg clutches at both low and high elevation. Regardless of maternal exposure to hypoxia during gestation, embryos incubated at extreme high elevation exhibited altered developmental trajectories of cardiovascular function and metabolism across the incubation period, including a reduction in late-development egg mass. This physiological response may have contributed to the maintenance of similar incubation duration, hatching success, and hatchling body size compared to embryos incubated at low elevation. Nevertheless, after being maintained in hypoxia, juveniles exhibit reduced carbon dioxide production relative to oxygen consumption, suggesting altered energy pathways compared to juveniles maintained in normoxia. These findings highlight the role of physiological plasticity in maintaining rates of survival and fitness-relevant phenotypes in novel environments.
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Affiliation(s)
- Jérémie Souchet
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | - Alicia Josserand
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | - Elodie Darnet
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | - Hugo Le Chevalier
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | - Audrey Trochet
- Société Herpétologique de France, Muséum National d'Histoire Naturelle, Paris, France
| | - Romain Bertrand
- Laboratoire Évolution et Diversité Biologique (UMR CNRS 5174), Université de Toulouse III Paul Sabatier, IRD, Toulouse, France
| | - Olivier Calvez
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | | | - Olivier Guillaume
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | | | | | - Hervé Philippe
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
| | - Fabien Aubret
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
- School of Molecular and Life Sciences, Curtin University, Perth, Australia
| | - Eric J Gangloff
- Station d'Ecologie Théorique et Expérimentale (UAR CNRS 2029), Moulis, France
- Department of Biological Sciences, Ohio Wesleyan University, Delaware, Ohio, USA
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2
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Burggren WW, Mendez-Sanchez JF. "Bet hedging" against climate change in developing and adult animals: roles for stochastic gene expression, phenotypic plasticity, epigenetic inheritance and adaptation. Front Physiol 2023; 14:1245875. [PMID: 37869716 PMCID: PMC10588650 DOI: 10.3389/fphys.2023.1245875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/12/2023] [Indexed: 10/24/2023] Open
Abstract
Animals from embryos to adults experiencing stress from climate change have numerous mechanisms available for enhancing their long-term survival. In this review we consider these options, and how viable they are in a world increasingly experiencing extreme weather associated with climate change. A deeply understood mechanism involves natural selection, leading to evolution of new adaptations that help cope with extreme and stochastic weather events associated with climate change. While potentially effective at staving off environmental challenges, such adaptations typically occur very slowly and incrementally over evolutionary time. Consequently, adaptation through natural selection is in most instances regarded as too slow to aid survival in rapidly changing environments, especially when considering the stochastic nature of extreme weather events associated with climate change. Alternative mechanisms operating in a much shorter time frame than adaptation involve the rapid creation of alternate phenotypes within a life cycle or a few generations. Stochastic gene expression creates multiple phenotypes from the same genotype even in the absence of environmental cues. In contrast, other mechanisms for phenotype change that are externally driven by environmental clues include well-understood developmental phenotypic plasticity (variation, flexibility), which can enable rapid, within-generation changes. Increasingly appreciated are epigenetic influences during development leading to rapid phenotypic changes that can also immediately be very widespread throughout a population, rather than confined to a few individuals as in the case of favorable gene mutations. Such epigenetically-induced phenotypic plasticity can arise rapidly in response to stressors within a generation or across a few generations and just as rapidly be "sunsetted" when the stressor dissipates, providing some capability to withstand environmental stressors emerging from climate change. Importantly, survival mechanisms resulting from adaptations and developmental phenotypic plasticity are not necessarily mutually exclusive, allowing for classic "bet hedging". Thus, the appearance of multiple phenotypes within a single population provides for a phenotype potentially optimal for some future environment. This enhances survival during stochastic extreme weather events associated with climate change. Finally, we end with recommendations for future physiological experiments, recommending in particular that experiments investigating phenotypic flexibility adopt more realistic protocols that reflect the stochastic nature of weather.
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Affiliation(s)
- Warren W. Burggren
- Developmental Integrative Biology Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Jose Fernando Mendez-Sanchez
- Laboratorio de Ecofisiología Animal, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma del Estado de México, Toluca, Mexico
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3
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Crossley JL, Smith B, Tull M, Elsey RM, Wang T, Crossley DA. Hypoxic incubation at 50% of atmospheric levels shifts the cardiovascular response to acute hypoxia in American alligators, Alligator mississippiensis. J Comp Physiol B 2023; 193:545-556. [PMID: 37615772 DOI: 10.1007/s00360-023-01510-8] [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: 08/12/2022] [Revised: 08/06/2023] [Accepted: 08/07/2023] [Indexed: 08/25/2023]
Abstract
We designed a series of studies to investigate whether hypoxia (10% O2) from 20% of incubation to hatching, or from 20 to 50% of incubation, affects cardiovascular function when juvenile American alligators reached an age of 4-5 years compared to juveniles that were incubated in 21% O2. At this age, we measured blood flows in all the major arteries as well as heart rate, blood pressure, and blood gases in animals in normoxia and acute hypoxia (10% O2 and 5% O2). In all three groups, exposure to acute hypoxia of 10% O2 caused a decrease in blood O2 concentration and an increase in heart rate in 4-5-year-old animals, with limited effects on blood flow in the major outflow vessels of the heart. In response to more acute hypoxia (5% O2), where blood O2 concentration decreased even further, we measured increased heart rate and blood flow in the right aorta, subclavian artery, carotid artery, and pulmonary artery; however, blood flow in the left aorta either decreased or did not change. Embryonic exposure to hypoxia increased the threshold for eliciting an increase in heart rate indicative of a decrease in sensitivity. Alligators that had been incubated in hypoxia also had higher arterial PCO2 values in normoxia, suggesting a reduction in ventilation relative to metabolism.
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Affiliation(s)
- Janna L Crossley
- Department of Surgery, Center for Organogenesis and Trauma, University of Texas Southwestern, Dallas, TX, 75390, USA
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX, 76203, USA
| | - Brandt Smith
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX, 76203, USA
| | - Melissa Tull
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX, 76203, USA
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA, 70643, USA
| | - Tobias Wang
- Department of Biology, Zoophysiology, Aarhus University, Aarhus C, Denmark
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX, 76203, USA.
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4
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Galli GLJ, Lock MC, Smith KLM, Giussani DA, Crossley DA. Effects of Developmental Hypoxia on the Vertebrate Cardiovascular System. Physiology (Bethesda) 2023; 38:0. [PMID: 36317939 DOI: 10.1152/physiol.00022.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 01/04/2023] Open
Abstract
Developmental hypoxia has profound and persistent effects on the vertebrate cardiovascular system, but the nature, magnitude, and long-term outcome of the hypoxic consequences are species specific. Here we aim to identify common and novel cardiovascular responses among vertebrates that encounter developmental hypoxia, and we discuss the possible medical and ecological implications.
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Affiliation(s)
- Gina L J Galli
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Mitchell C Lock
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Kerri L M Smith
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Dino A Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas
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Bautista NM, Petersen EE, Jensen RJ, Natarajan C, Storz JF, Crossley DA, Fago A. Changes in hemoglobin function and isoform expression during embryonic development in the American alligator, Alligator mississippiensis. Am J Physiol Regul Integr Comp Physiol 2021; 321:R869-R878. [PMID: 34704846 DOI: 10.1152/ajpregu.00047.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the developing embryos of egg-laying vertebrates, O2 flux takes place across a fixed surface area of the eggshell and the chorioallantoic membrane. In the case of crocodilians, the developing embryo may experience a decrease in O2 flux when the nest becomes hypoxic, which may cause compensatory adjustments in blood O2 transport. However, whether the switch from embryonic to adult hemoglobin isoforms (isoHbs) plays some role in these adjustments is unknown. Here, we provide a detailed characterization of the developmental switch of isoHb synthesis in the American alligator, Alligator mississippiensis. We examined the in vitro functional properties and subunit composition of purified alligator isoHbs expressed during embryonic developmental stages in normoxia and hypoxia (10% O2). We found distinct patterns of isoHb expression in alligator embryos at different stages of development, but these patterns were not affected by hypoxia. Specifically, alligator embryos expressed two main isoHbs: HbI, prevalent at early developmental stages, with a high O2 affinity and high ATP sensitivity, and HbII, prevalent at later stages and identical to the adult protein, with a low O2 affinity and high CO2 sensitivity. These results indicate that whole blood O2 affinity is mainly regulated by ATP in the early embryo and by CO2 and bicarbonate from the late embryo until adult life, but the developmental regulation of isoHb expression is not affected by hypoxia exposure.
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Affiliation(s)
| | | | | | | | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas
| | - Angela Fago
- Department of Biology, Aarhus University, Aarhus C, Denmark
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Ruhr I, Bierstedt J, Rhen T, Das D, Singh SK, Miller S, Crossley DA, Galli GLJ. Developmental programming of DNA methylation and gene expression patterns is associated with extreme cardiovascular tolerance to anoxia in the common snapping turtle. Epigenetics Chromatin 2021; 14:42. [PMID: 34488850 PMCID: PMC8420019 DOI: 10.1186/s13072-021-00414-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/02/2021] [Indexed: 12/15/2022] Open
Abstract
Background Environmental fluctuation during embryonic and fetal development can permanently alter an organism’s morphology, physiology, and behaviour. This phenomenon, known as developmental plasticity, is particularly relevant to reptiles that develop in subterranean nests with variable oxygen tensions. Previous work has shown hypoxia permanently alters the cardiovascular system of snapping turtles and may improve cardiac anoxia tolerance later in life. The mechanisms driving this process are unknown but may involve epigenetic regulation of gene expression via DNA methylation. To test this hypothesis, we assessed in situ cardiac performance during 2 h of acute anoxia in juvenile turtles previously exposed to normoxia (21% oxygen) or hypoxia (10% oxygen) during embryogenesis. Next, we analysed DNA methylation and gene expression patterns in turtles from the same cohorts using whole genome bisulfite sequencing, which represents the first high-resolution investigation of DNA methylation patterns in any reptilian species. Results Genome-wide correlations between CpG and CpG island methylation and gene expression patterns in the snapping turtle were consistent with patterns observed in mammals. As hypothesized, developmental hypoxia increased juvenile turtle cardiac anoxia tolerance and programmed DNA methylation and gene expression patterns. Programmed differences in expression of genes such as SCN5A may account for differences in heart rate, while genes such as TNNT2 and TPM3 may underlie differences in calcium sensitivity and contractility of cardiomyocytes and cardiac inotropy. Finally, we identified putative transcription factor-binding sites in promoters and in differentially methylated CpG islands that suggest a model linking programming of DNA methylation during embryogenesis to differential gene expression and cardiovascular physiology later in life. Binding sites for hypoxia inducible factors (HIF1A, ARNT, and EPAS1) and key transcription factors activated by MAPK and BMP signaling (RREB1 and SMAD4) are implicated. Conclusions Our data strongly suggests that DNA methylation plays a conserved role in the regulation of gene expression in reptiles. We also show that embryonic hypoxia programs DNA methylation and gene expression patterns and that these changes are associated with enhanced cardiac anoxia tolerance later in life. Programming of cardiac anoxia tolerance has major ecological implications for snapping turtles, because these animals regularly exploit anoxic environments throughout their lifespan. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00414-7.
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Affiliation(s)
- Ilan Ruhr
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, M13 9NT, UK
| | - Jacob Bierstedt
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Turk Rhen
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA.
| | - Debojyoti Das
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Sunil Kumar Singh
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Soleille Miller
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA
| | - Gina L J Galli
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, M13 9NT, UK
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7
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Prenatal hypoxia affects scaling of blood pressure and arterial wall mechanics in the common snapping turtle, Chelydra serpentina. Comp Biochem Physiol A Mol Integr Physiol 2021; 260:111023. [PMID: 34224856 DOI: 10.1016/j.cbpa.2021.111023] [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: 03/09/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 11/24/2022]
Abstract
In reptiles, exposure to hypoxia during embryonic development affects several cardiovascular parameters. These modifications may impose different mechanical stress to the arterial system, and we speculated that the arterial wall of major outflow vessels would be modified accordingly. Since non-crocodilian reptiles possess a partially divided ventricle, ensuing similar systemic and pulmonary systolic pressures, we investigated how morphological and mechanical properties of segments from the left aortic arch (LAo) and the proximal and distal segments of the left pulmonary artery (LPAp and LPAd, respectively) change as body mass (Mb) increases. Eggs from common snapping turtles, Chelydra serpentina, were incubated under normoxia (21% O2; N21) or hypoxia (10% O2; H10), hatched and maintained in normoxia thereafter. Turtles (0.11-6.85 kg) were cannulated to measure arterial pressures, and an injection of adrenaline was used to increase pressures. Portions of the LAo, LPAp and LPAd were fixed under physiological hydrostatic pressures for histology and mechanical assessment. Arterial pressures increased with Mb for N21 but not for H10. Although mechanical and functional characteristics from the LPAp and LPAd were similar between N21 and H10, wall thickness from LAo did not change with Mb in the H10 group, thus wall stress increased in larger turtles. This indicates that larger H10 turtles probably experience an elevated probability of arterial wall rupture without concomitant changes in the cardiovascular system to prevent it. Finally, collagen content of the LPAp and LAo was smaller than in LPAd, suggesting a more distensible arterial wall could attenuate higher pressures from larger turtles.
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Galli GLJ, Ruhr IM, Crossley J, Crossley DA. The Long-Term Effects of Developmental Hypoxia on Cardiac Mitochondrial Function in Snapping Turtles. Front Physiol 2021; 12:689684. [PMID: 34262478 PMCID: PMC8273549 DOI: 10.3389/fphys.2021.689684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/03/2021] [Indexed: 01/05/2023] Open
Abstract
It is well established that adult vertebrates acclimatizing to hypoxic environments undergo mitochondrial remodeling to enhance oxygen delivery, maintain ATP, and limit oxidative stress. However, many vertebrates also encounter oxygen deprivation during embryonic development. The effects of developmental hypoxia on mitochondrial function are likely to be more profound, because environmental stress during early life can permanently alter cellular physiology and morphology. To this end, we investigated the long-term effects of developmental hypoxia on mitochondrial function in a species that regularly encounters hypoxia during development-the common snapping turtle (Chelydra serpentina). Turtle eggs were incubated in 21% or 10% oxygen from 20% of embryonic development until hatching, and both cohorts were subsequently reared in 21% oxygen for 8 months. Ventricular mitochondria were isolated, and mitochondrial respiration and reactive oxygen species (ROS) production were measured with a microrespirometer. Compared to normoxic controls, juvenile turtles from hypoxic incubations had lower Leak respiration, higher P:O ratios, and reduced rates of ROS production. Interestingly, these same attributes occur in adult vertebrates that acclimatize to hypoxia. We speculate that these adjustments might improve mitochondrial hypoxia tolerance, which would be beneficial for turtles during breath-hold diving and overwintering in anoxic environments.
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Affiliation(s)
- Gina L. J. Galli
- Faculty of Biology, Medicine, and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Ilan M. Ruhr
- Faculty of Biology, Medicine, and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Janna Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Dane A. Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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9
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Eme J, Tate KB, Rhen T, Crossley DA. Cardiovascular responses to putative chemoreceptor stimulation of embryonic common snapping turtles (Chelydra serpentina) chronically incubated in hypoxia (10% O 2). Comp Biochem Physiol A Mol Integr Physiol 2021; 259:110977. [PMID: 33984502 DOI: 10.1016/j.cbpa.2021.110977] [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: 03/16/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 11/19/2022]
Abstract
Developmental hypoxia has been shown to result in significant changes in cardiovascular development of American alligators and common snapping turtles. These include similar effects on cardiac mass and aspects of cardiovascular function. However, given the distant phylogenetic relationship between crocodilians and chelonians, we hypothesized that snapping turtles would also exhibit differences in the effects of developmental hypoxia on cardiovascular regulation. This hypothesis was based in part on prior studies that documented differences in plasticity of vagal tone on the heart between alligators and snapping turtles incubated in hypoxic conditions. To test this hypothesis, we investigated how 10% O2 exposure over final 80% of incubation altered the heart rate and blood pressure response to two chemical manipulations of the "chemoreflex" in common snapping turtles at 70% and 90% of incubation. NaCN injections produced a dose dependent bradycardia that was mediated by cholinergic receptor stimulation. This reflex was relatively unaffected by hypoxic incubation conditions in snapping turtle embryos. Injections of the 5-HT3 agonist phenylbiguanide (PBG) caused a pronounced bradycardia that decreased in intensity at 90% of incubation in embryos from the normoxic group while the heart rate response was unchanged in the hypoxic group. This differs from the previously reported diminished heart rate response of embryonic alligators incubated in 10% O2, suggesting plasticity in this chemoreflex response differs between the species. Our data also indicate the cardiovascular response is mediated by a secondary cholinergic receptor stimulation however the inability of ganglionic blockade to inhibit the PBG response leaves the location of the receptors antagonized by PBG in question in embryonic snapping turtles. Primarily, our findings refute the hypothesis that hypoxic incubation decreases the "chemoreflex' response of snapping turtle embryos.
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Affiliation(s)
- John Eme
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, United States of America.
| | - Kevin B Tate
- Department of Biology, Texas Lutheran University, 1000 W. Court St., Seguin, TX 78155, United States of America.
| | - Turk Rhen
- Department of Biology, University of North Dakota, 10 Cornell St Stop 9019, Grand Forks, ND 58202, United States of America.
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, 1155 Union Circle #310559, Denton, TX 76203, United States of America.
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Little AG, Pamenter ME, Sitaraman D, Templeman NM, Willmore WG, Hedrick MS, Moyes CD. WITHDRAWN: Utilizing comparative models in biomedical research. Comp Biochem Physiol A Mol Integr Physiol 2021; 256:110938. [PMID: 33737041 DOI: 10.1016/j.cbpa.2021.110938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The Publisher regrets that this article is an accidental duplication of an article that has already been published in Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, Volume 255, 2021, 110593, https://doi.org/10.1016/j.cbpb.2021.110593. The duplicate article has therefore been withdrawn.
The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
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Affiliation(s)
| | | | - Divya Sitaraman
- Department of Psychology, California State University, East Bay, Hayward, CA, USA
| | | | | | - Michael S Hedrick
- Department of Biological Sciences, California State University, East Bay, Hayward, CA, USA.
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Little AG, Pamenter ME, Sitaraman D, Templeman NM, Willmore WG, Hedrick MS, Moyes CD. Utilizing comparative models in biomedical research. Comp Biochem Physiol B Biochem Mol Biol 2021; 255:110593. [PMID: 33779562 DOI: 10.1016/j.cbpb.2021.110593] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This review serves as an introduction to a Special Issue of Comparative Biochemistry and Physiology, focused on using non-human models to study biomedical physiology. The concept of a model differs across disciplines. For example, several models are used primarily to gain an understanding of specific human pathologies and disease states, whereas other models may be focused on gaining insight into developmental or evolutionary mechanisms. It is often the case that animals initially used to gain knowledge of some unique biochemical or physiological process finds foothold in the biomedical community and becomes an established model. The choice of a particular model for biomedical research is an ongoing process and model validation must keep pace with existing and emerging technologies. While the importance of non-mammalian models, such as Caenorhabditis elegans, Drosophila melanogaster, Danio rerio and Xenopus laevis, is well known, we also seek to bring attention to emerging alternative models of both invertebrates and vertebrates, which are less established but of interest to the comparative biochemistry and physiology community.
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Affiliation(s)
| | | | - Divya Sitaraman
- Department of Psychology, California State University, East Bay, Hayward, CA, USA
| | | | | | - Michael S Hedrick
- Department of Biological Sciences, California State University, East Bay, Hayward, CA, USA
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Survival, Growth, and Development in the Early Stages of the Tropical Gar Atractosteus tropicus: Developmental Critical Windows and the Influence of Temperature, Salinity, and Oxygen Availability. FISHES 2021. [DOI: 10.3390/fishes6010005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alterations in fish developmental trajectories occur in response to genetic and environmental changes, especially during sensitive periods of development (critical windows). Embryos and larvae of Atractosteus tropicus were used as a model to study fish survival, growth, and development as a function of temperature (28 °C control, 33 °C, and 36 °C), salinity (0.0 ppt control, 4.0 ppt, and 6.0 ppt), and air saturation (control ~95% air saturation, hypoxia ~30% air saturation, and hyperoxia ~117% air saturation) during three developmental periods: (1) fertilization to hatch, (2) day 1 to day 6 post hatch (dph), and (3) 7 to 12 dph. Elevated temperature, hypoxia, and hyperoxia decreased survival during incubation, and salinity at 2 and 3 dph. Growth increased in embryos incubated at elevated temperature, at higher salinity, and in hyperoxia but decreased in hypoxia. Changes in development occurred as alterations in the timing of hatching, yolk depletion, acceptance of exogenous feeding, free swimming, and snout shape change, especially at high temperature and hypoxia. Our results suggest identifiable critical windows of development in the early ontogeny of A. tropicus and contribute to the knowledge of fish larval ecology and the interactions of individuals × stressors × time of exposure.
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13
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Burggren WW. Phenotypic Switching Resulting From Developmental Plasticity: Fixed or Reversible? Front Physiol 2020; 10:1634. [PMID: 32038303 PMCID: PMC6987144 DOI: 10.3389/fphys.2019.01634] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/27/2019] [Indexed: 12/19/2022] Open
Abstract
The prevalent view of developmental phenotypic switching holds that phenotype modifications occurring during critical windows of development are "irreversible" - that is, once produced by environmental perturbation, the consequent juvenile and/or adult phenotypes are indelibly modified. Certainly, many such changes appear to be non-reversible later in life. Yet, whether animals with switched phenotypes during early development are unable to return to a normal range of adult phenotypes, or whether they do not experience the specific environmental conditions necessary for them to switch back to the normal range of adult phenotypes, remains an open question. Moreover, developmental critical windows are typically brief, early periods punctuating a much longer period of overall development. This leaves open additional developmental time for reversal (correction) of a switched phenotype resulting from an adverse environment early in development. Such reversal could occur from right after the critical window "closes," all the way into adulthood. In fact, examples abound of the capacity to return to normal adult phenotypes following phenotypic changes enabled by earlier developmental plasticity. Such examples include cold tolerance in the fruit fly, developmental switching of mouth formation in a nematode, organization of the spinal cord of larval zebrafish, camouflage pigmentation formation in larval newts, respiratory chemosensitivity in frogs, temperature-metabolism relations in turtles, development of vascular smooth muscle and kidney tissue in mammals, hatching/birth weight in numerous vertebrates,. More extreme cases of actual reversal (not just correction) occur in invertebrates (e.g., hydrozoans, barnacles) that actually 'backtrack' along normal developmental trajectories from adults back to earlier developmental stages. While developmental phenotypic switching is often viewed as a permanent deviation from the normal range of developmental plans, the concept of developmental phenotypic switching should be expanded to include sufficient plasticity allowing subsequent correction resulting in the normal adult phenotype.
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Affiliation(s)
- Warren W. Burggren
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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Smith B, Crossley JL, Elsey RM, Hicks JW, Crossley DA. Embryonic developmental oxygen preconditions cardiovascular functional response to acute hypoxic exposure and maximal β-adrenergic stimulation of anesthetized juvenile American alligators ( Alligator mississippiensis). ACTA ACUST UNITED AC 2019; 222:jeb.205419. [PMID: 31548289 DOI: 10.1242/jeb.205419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/16/2019] [Indexed: 12/31/2022]
Abstract
The effects of the embryonic environment on juvenile phenotypes are widely recognized. We investigated the effect of embryonic hypoxia on the cardiovascular phenotype of 4-year-old American alligators (Alligator mississippiensis). We hypothesized that embryonic 10% O2 preconditions cardiac function, decreasing the reduction in cardiac contractility associated with acute 5% O2 exposure in juvenile alligators. Our findings indicate that dobutamine injections caused a 90% increase in systolic pressure in juveniles that were incubated in 21% and 10% O2, with the 10% O2 group responding with a greater rate of ventricular relaxation and greater left ventricle output compared with the 21% O2 group. Further, our findings indicate that juvenile alligators that experienced embryonic hypoxia have a faster rate of ventricular relaxation, greater left ventricle stroke volume and greater cardiac power following β-adrenergic stimulation, compared with juvenile alligators that did not experience embryonic hypoxia. When juveniles were exposed to 5% O2 for 20 min, normoxic-incubated juveniles had a 50% decline in left ventricle maximal rate of pressure development and maximal pressure; however, these parameters were unaffected and decreased less in the hypoxic-incubated juveniles. These data indicate that embryonic hypoxia in crocodilians alters the cardiovascular phenotype, changing the juvenile response to acute hypoxia and β-adrenergic stimulation.
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Affiliation(s)
- Brandt Smith
- Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - Janna L Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, LA 70643, USA
| | - James W Hicks
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
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15
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Sartori MR, Kohl ZF, Taylor EW, Abe AS, Crossley Ii DA. Blood flow distribution in embryonic common snapping turtles Chelydra serpentina (Reptilia; Chelonia) during acute hypoxia and α-adrenergic regulation. Comp Biochem Physiol A Mol Integr Physiol 2019; 238:110575. [PMID: 31505219 DOI: 10.1016/j.cbpa.2019.110575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 10/26/2022]
Abstract
Embryonic turtles have four distinct vascular beds that separately perfuse the developing embryo's body and the extra-embryonic yolk sac, amnion and chorioallantoic membrane (CAM). The mechanisms enabling differential regulation of blood flow through these separate beds, in order to meet the varying demands of the embryo during development, is of current interest. The present investigation followed the changes in blood flow distribution during an acute exposure to hypoxia and after α-adrenergic blockade. We monitored heart rate (fH), mean arterial pressure (Pm), and determined relative blood flow distribution (%Q̇sys) using colored microspheres. At 70% and 90% of the incubation period hypoxia elicited a bradycardia without changing Pm while %Q̇sys was altered only at 70%, increasing to the CAM and liver. Blockade of α-adrenergic responses with phentolamine did not change fH or Pm but increased %Q̇sys to the shell. These results show the capacity of embryos to redistribute cardiac output during acute hypoxia, however α-adrenergic receptors seemed to play a relatively small role in embryonic cardiovascular regulation.
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Affiliation(s)
- Marina R Sartori
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Campus Rio Claro, SP 13506-900, Brazil; Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX 76203-5017, USA.
| | - Zachary F Kohl
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX 76203-5017, USA
| | - Edwin W Taylor
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Campus Rio Claro, SP 13506-900, Brazil; School of Biosciences, University of Birmingham, B15 2TT, UK
| | - Augusto S Abe
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Campus Rio Claro, SP 13506-900, Brazil
| | - Dane A Crossley Ii
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX 76203-5017, USA
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Ruhr IM, McCourty H, Bajjig A, Crossley DA, Shiels HA, Galli GLJ. Developmental plasticity of cardiac anoxia-tolerance in juvenile common snapping turtles ( Chelydra serpentina). Proc Biol Sci 2019; 286:20191072. [PMID: 31238852 PMCID: PMC6599983 DOI: 10.1098/rspb.2019.1072] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
For some species of ectothermic vertebrates, early exposure to hypoxia during embryonic development improves hypoxia-tolerance later in life. However, the cellular mechanisms underlying this phenomenon are largely unknown. Given that hypoxic survival is critically dependent on the maintenance of cardiac function, we tested the hypothesis that developmental hypoxia alters cardiomyocyte physiology in a manner that protects the heart from hypoxic stress. To test this hypothesis, we studied the common snapping turtle, which routinely experiences chronic developmental hypoxia and exploits hypoxic environments in adulthood. We isolated cardiomyocytes from juvenile turtles that embryonically developed in either normoxia (21% O2) or hypoxia (10% O2), and subjected them to simulated anoxia and reoxygenation, while simultaneously measuring intracellular Ca2+, pH and reactive oxygen species (ROS) production. Our results suggest developmental hypoxia improves cardiomyocyte anoxia-tolerance of juvenile turtles, which is supported by enhanced myofilament Ca2+-sensitivity and a superior ability to suppress ROS production. Maintenance of low ROS levels during anoxia might limit oxidative damage and a greater sensitivity to Ca2+ could provide a mechanism to maintain contractile force. Our study suggests developmental hypoxia has long-lasting effects on turtle cardiomyocyte function, which might prime their physiology for exploiting hypoxic environments.
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Affiliation(s)
- Ilan M Ruhr
- 1 Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester , Manchester M13 9NT , UK
| | - Heather McCourty
- 1 Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester , Manchester M13 9NT , UK
| | - Afaf Bajjig
- 1 Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester , Manchester M13 9NT , UK
| | - Dane A Crossley
- 2 Department of Biological Sciences, University of North Texas , Denton, TX 76203 , USA
| | - Holly A Shiels
- 1 Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester , Manchester M13 9NT , UK
| | - Gina L J Galli
- 1 Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester , Manchester M13 9NT , UK
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17
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Alderman SL, Crossley DA, Elsey RM, Gillis TE. Hypoxia-induced reprogramming of the cardiac phenotype in American alligators (Alligator mississippiensis) revealed by quantitative proteomics. Sci Rep 2019; 9:8592. [PMID: 31197188 PMCID: PMC6565670 DOI: 10.1038/s41598-019-45023-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/29/2019] [Indexed: 02/06/2023] Open
Abstract
Hypoxic exposure during development can have a profound influence on offspring physiology, including cardiac dysfunction, yet many reptile embryos naturally experience periods of hypoxia in buried nests. American alligators experimentally exposed to developmental hypoxia demonstrate morphological and functional changes to the heart that persist into later life stages; however, the molecular bases of these changes remain unknown. We tested if targeted and persistent changes in steady-state protein expression underlie this hypoxic heart phenotype, using isobaric tags for relative and absolute quantitation (iTRAQ) proteomics. Alligator eggs were reared under normoxia or 10% hypoxia, then either sampled (embryo) or returned to normoxia for 2 years (juvenile). Three salient findings emerge from the integrated analysis of the 145 differentially expressed proteins in hypoxia-reared animals: (1) significant protein-protein interaction networks were identified only in up-regulated proteins, indicating that the effects of developmental hypoxia are stimulatory and directed; (2) the up-regulated proteins substantially enriched processes related to protein turnover, cellular organization, and metabolic pathways, supporting increased resource allocation towards building and maintaining a higher functioning heart; and (3) the juvenile cardiac proteome retained many of the signature changes observed in embryonic hearts, supporting long-term reprogramming of cardiac myocytes induced by hypoxia during critical periods of development.
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Affiliation(s)
- Sarah L Alderman
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
| | - Dane A Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, Texas, 76203-5017, USA
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, 70643, USA
| | - Todd E Gillis
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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18
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Nelson D, Crossley DA, Elsey RM, Tate KB. Cardiovascular adjustments with egg temperature at 90% incubation in embryonic American alligators, Alligator mississippiensis. J Comp Physiol B 2018; 188:471-480. [PMID: 29380053 DOI: 10.1007/s00360-018-1144-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/15/2017] [Accepted: 01/03/2018] [Indexed: 01/14/2023]
Abstract
American alligators (Alligator mississippiensis) deposit eggs in a mound nest, potentially subjecting embryos to daily variations in temperature. Whilst adult crocodilian cardiovascular responses to changes in temperature have been investigated, similar studies in alligator embryos are limited. We investigated cardiovascular function of embryonic alligators during heating and cooling as well as at different temperatures. We measured arterial blood pressure (Pm) and heart rate (fH) in response to cooling (30-26 °C), heating (26-36 °C), followed by a reciprocal cooling event (36-26 °C) and assessed the cardiac baroreflex at 30 and 36 °C. Embryonic fH increased during heating events and decreased during cooling events, while embryos were hypotensive at 26 and 36 °C, although Pm did not differ between heating or cooling events. There was a clear temperature-dependent heart rate hysteresis at a given embryo's temperature, depending on whether embryos were cooling or heating. Cardiovascular regulation through the cardiac limb of the baroreflex was not affected by temperature, despite previous studies suggesting that vagal tone is present at both low and high temperatures.
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Affiliation(s)
- Derek Nelson
- Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203-5017, USA
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203-5017, USA.
| | - Ruth M Elsey
- Department of Wildlife and Fisheries, Grand Chenier, LA, USA
| | - Kevin B Tate
- Department of Biology, Truman State University Kirksville, Louisiana, MO, USA
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CORDERO GA, KARNATZ ML, SVENDSEN JC, GANGLOFF EJ. Effects of low-oxygen conditions on embryo growth in the painted turtle,Chrysemys picta. Integr Zool 2017; 12:148-156. [DOI: 10.1111/1749-4877.12206] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gerardo A. CORDERO
- Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames Iowa USA
| | - Matthew L. KARNATZ
- Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames Iowa USA
| | - Jon C. SVENDSEN
- Technical University of Denmark, National Institute of Aquatic Resources; Freshwater Fisheries Silkeborg Denmark
- Interdisciplinary Centre of Marine and Environmental Research; University of Porto; Porto Portugal
| | - Eric J. GANGLOFF
- Department of Ecology, Evolution, and Organismal Biology; Iowa State University; Ames Iowa USA
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20
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Crossley DA, Ling R, Nelson D, Gillium T, Conner J, Hapgood J, Elsey RM, Eme J. Metabolic responses to chronic hypoxic incubation in embryonic American alligators (Alligator mississippiensis). Comp Biochem Physiol A Mol Integr Physiol 2017; 203:77-82. [DOI: 10.1016/j.cbpa.2016.08.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/10/2016] [Accepted: 08/16/2016] [Indexed: 11/28/2022]
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21
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Foucart T, Heulin B, Lourdais O. Clutch size influences embryonic stages at oviposition in a lizard with prolonged egg retention. AMPHIBIA-REPTILIA 2017. [DOI: 10.1163/15685381-00003128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examined the possible interaction between reproductive effort and embryonic stages at oviposition in oviparous form of the lizard Zootoca vivipara. Our results reveal that the percentage of total embryonic development time (%TEDT) reached at oviposition is negatively correlated to clutch size (adjusted to maternal body size). We found no influence of reproductive burden of female (relative clutch mass, RCM) on %TEDT. The significant effect of fecundity supports the hypothesis that a resource limitation such as oxygen may exist for developing embryos in oviducts. The absence of RCM effect suggests that the available space (abdominal burdening of the mother) does not limit the embryonic stages at oviposition.
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Affiliation(s)
- Thomas Foucart
- Station Biologique de Paimpont, UMR 6553 CNRS, F-35380, Paimpont, France
- Centre d’étude biologique de Chizé CNRS, F-79360, Villiers en Bois, France
| | - Benoit Heulin
- Station Biologique de Paimpont, UMR 6553 CNRS, F-35380, Paimpont, France
| | - Olivier Lourdais
- Centre d’étude biologique de Chizé CNRS, F-79360, Villiers en Bois, France
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
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22
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Wearing OH, Conner J, Nelson D, Crossley J, Crossley DA. Embryonic hypoxia programmes postprandial cardiovascular function in adult common snapping turtles (Chelydra serpentina). J Exp Biol 2017; 220:2589-2597. [DOI: 10.1242/jeb.160549] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 05/03/2017] [Indexed: 12/20/2022]
Abstract
Reduced oxygen availability (hypoxia) is a potent stressor during embryonic development, altering the trajectory of trait maturation and organismal phenotype. We previously documented that chronic embryonic hypoxia has a lasting impact on the metabolic response to feeding in juvenile snapping turtles (Chelydra serpentina). Turtles exposed to hypoxia as embryos (10% O2, H10) exhibited an earlier and increased peak postprandial oxygen consumption rate, compared to control turtles (21% O2, N21). In the current study, we measured central blood flow patterns to determine whether the elevated postprandial metabolic response in H10 turtles is linked to lasting impacts on convective transport. Five years after hatching, turtles were instrumented to quantify systemic (Q̇sys) and pulmonary (Q̇pul) blood flows and heart rate (fH) before and after a ∼5% body mass meal. In adult N21 and H10 turtles, fH was increased significantly by feeding. While total stroke volume (Vstot) remained at fasted values, this tachycardia contributed to an elevation in total cardiac output (Q̇tot). However, there was a postprandial reduction in a net left-right (L-R) shunt in N21 snapping turtles only. Relative to N21 turtles, H10 animals exhibited higher Q̇sys due to increased blood flow through the right systemic outflow vessels of the heart. This effect of hypoxic embryonic development, reducing a net L-R cardiac shunt, may support the increased postprandial metabolic rate we previously reported in H10 turtles, and is further demonstration of adult reptile cardiovascular physiology being programmed by embryonic hypoxia.
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Affiliation(s)
- Oliver H. Wearing
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Justin Conner
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Derek Nelson
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Janna Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
| | - Dane A. Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas, USA
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23
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Tate KB, Rhen T, Eme J, Kohl ZF, Crossley J, Elsey RM, Crossley DA. Periods of cardiovascular susceptibility to hypoxia in embryonic american alligators (Alligator mississippiensis). Am J Physiol Regul Integr Comp Physiol 2016; 310:R1267-78. [PMID: 27101296 DOI: 10.1152/ajpregu.00320.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 04/11/2016] [Indexed: 01/30/2023]
Abstract
During embryonic development, environmental perturbations can affect organisms' developing phenotype, a process known as developmental plasticity. Resulting phenotypic changes can occur during discrete, critical windows of development. Critical windows are periods when developing embryos are most susceptible to these perturbations. We have previously documented that hypoxia reduces embryo size and increases relative heart mass in American alligator, and this study identified critical windows when hypoxia altered morphological, cardiovascular function and cardiac gene expression of alligator embryos. We hypothesized that incubation in hypoxia (10% O2) would increase relative cardiac size due to cardiac enlargement rather than suppression of somatic growth. We exposed alligator embryos to hypoxia during discrete incubation periods to target windows where the embryonic phenotype is altered. Hypoxia affected heart growth between 20 and 40% of embryonic incubation, whereas somatic growth was affected between 70 and 90% of incubation. Arterial pressure was depressed by hypoxic exposure during 50-70% of incubation, whereas heart rate was depressed in embryos exposed to hypoxia during a period spanning 70-90% of incubation. Expression of Vegf and PdgfB was increased in certain hypoxia-exposed embryo treatment groups, and hypoxia toward the end of incubation altered β-adrenergic tone for arterial pressure and heart rate. It is well known that hypoxia exposure can alter embryonic development, and in the present study, we have identified brief, discrete windows that alter the morphology, cardiovascular physiology, and gene expression in embryonic American alligator.
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Affiliation(s)
- Kevin B Tate
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Turk Rhen
- Department of Biology, University of North Dakota, Grand Forks, North Dakota
| | - John Eme
- Department of Biological Sciences, California State University San Marcos, San Marcos, California
| | - Zachary F Kohl
- Department of Biological Sciences, University of North Texas, Denton, Texas; and
| | - Janna Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas; and
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas; and
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Mueller CA, Willis E, Burggren WW. Salt sensitivity of the morphometry of Artemia franciscana during development: a demonstration of 3D critical windows. ACTA ACUST UNITED AC 2015; 219:571-81. [PMID: 26685168 DOI: 10.1242/jeb.125823] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 12/01/2015] [Indexed: 11/20/2022]
Abstract
A 3D conceptual framework of 'critical windows' was used to examine whether the morphometry of Artemia franciscana is altered by salinity exposure during certain key periods of development. Artemia franciscana were hatched at 20 ppt (designated control salinity) and were then exposed to 10, 30, 40 or 50 ppt either chronically (days 1-15) or only on days 1-6, 7-9, 10-12 or 13-15. On day 15, maturity was assessed and morphometric characteristics, including mass, total body length, tail length and width, length of the third swimming appendage and eye diameter, were measured. Maturation and morphometry on day 15 were influenced by the exposure window and salinity dose. Artemia franciscana were generally larger following exposure to 10 and 40 ppt during days 1-6 and 7-9 when compared with days 10-12 and 13-15, in part due to a higher percentage of mature individuals. Exposure to different salinities on days 1-6 produced the greatest differences in morphometry, and thus this appears to be a period in development when A. franciscana is particularly sensitive to salinity. Viewing the developmental window as three-dimensional allowed more effective visualization of the complex interactions between exposure window, stressor dose and the magnitude of morphometric changes in A. franciscana.
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Affiliation(s)
- Casey A Mueller
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA 92096, USA
| | - Eric Willis
- Developmental Integrative Biology Group, Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - Warren W Burggren
- Developmental Integrative Biology Group, Department of Biological Sciences, University of North Texas, Denton, TX, USA
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25
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Wearing OH, Eme J, Rhen T, Crossley DA. Phenotypic plasticity in the common snapping turtle (Chelydra serpentina): long-term physiological effects of chronic hypoxia during embryonic development. Am J Physiol Regul Integr Comp Physiol 2015; 310:R176-84. [PMID: 26608655 DOI: 10.1152/ajpregu.00293.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/24/2015] [Indexed: 11/22/2022]
Abstract
Studies of embryonic and hatchling reptiles have revealed marked plasticity in morphology, metabolism, and cardiovascular function following chronic hypoxic incubation. However, the long-term effects of chronic hypoxia have not yet been investigated in these animals. The aim of this study was to determine growth and postprandial O2 consumption (V̇o2), heart rate (fH), and mean arterial pressure (Pm, in kPa) of common snapping turtles (Chelydra serpentina) that were incubated as embryos in chronic hypoxia (10% O2, H10) or normoxia (21% O2, N21). We hypothesized that hypoxic development would modify posthatching body mass, metabolic rate, and cardiovascular physiology in juvenile snapping turtles. Yearling H10 turtles were significantly smaller than yearling N21 turtles, both of which were raised posthatching in normoxic, common garden conditions. Measurement of postprandial cardiovascular parameters and O2 consumption were conducted in size-matched three-year-old H10 and N21 turtles. Both before and 12 h after feeding, H10 turtles had a significantly lower fH compared with N21 turtles. In addition, V̇o2 was significantly elevated in H10 animals compared with N21 animals 12 h after feeding, and peak postprandial V̇o2 occurred earlier in H10 animals. Pm of three-year-old turtles was not affected by feeding or hypoxic embryonic incubation. Our findings demonstrate that physiological impacts of developmental hypoxia on embryonic reptiles continue into juvenile life.
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Affiliation(s)
- Oliver H Wearing
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - John Eme
- Department of Biological Sciences, California State University San Marcos, San Marcos, California
| | - Turk Rhen
- Department of Biology, University of North Dakota, Grand Forks, North Dakota; and
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, Texas
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26
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Eme J, A. Crossley D. Chronic hypercapnic incubation increases relative organ growth and reduces blood pressure of embryonic American alligator ( Alligator mississippiensis ). Comp Biochem Physiol A Mol Integr Physiol 2015; 182:53-7. [DOI: 10.1016/j.cbpa.2014.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 11/16/2014] [Accepted: 12/02/2014] [Indexed: 10/24/2022]
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27
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Mueller CA, Eme J, Burggren WW, Roghair RD, Rundle SD. Challenges and opportunities in developmental integrative physiology. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:113-24. [PMID: 25711780 DOI: 10.1016/j.cbpa.2015.02.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/15/2015] [Accepted: 02/17/2015] [Indexed: 01/20/2023]
Abstract
This review explores challenges and opportunities in developmental physiology outlined by a symposium at the 2014 American Physiological Society Intersociety Meeting: Comparative Approaches to Grand Challenges in Physiology. Across animal taxa, adverse embryonic/fetal environmental conditions can alter morphological and physiological phenotypes in juveniles or adults, and capacities for developmental plasticity are common phenomena. Human neonates with body sizes at the extremes of perinatal growth are at an increased risk of adult disease, particularly hypertension and cardiovascular disease. There are many rewarding areas of current and future research in comparative developmental physiology. We present key mechanisms, models, and experimental designs that can be used across taxa to investigate patterns in, and implications of, the development of animal phenotypes. Intraspecific variation in the timing of developmental events can be increased through developmental plasticity (heterokairy), and could provide the raw material for selection to produce heterochrony--an evolutionary change in the timing of developmental events. Epigenetics and critical windows research recognizes that in ovo or fetal development represent a vulnerable period in the life history of an animal, when the developing organism may be unable to actively mitigate environmental perturbations. 'Critical windows' are periods of susceptibility or vulnerability to environmental or maternal challenges, periods when recovery from challenge is possible, and periods when the phenotype or epigenome has been altered. Developmental plasticity may allow survival in an altered environment, but it also has possible long-term consequences for the animal. "Catch-up growth" in humans after the critical perinatal window has closed elicits adult obesity and exacerbates a programmed hypertensive phenotype (one of many examples of "fetal programing"). Grand challenges for developmental physiology include integrating variation in developmental timing within and across generations, applying multiple stressor dosages and stressor exposure at different developmental timepoints, assessment of epigenetic and parental influences, developing new animal models and techniques, and assessing and implementing these designs and models in human health and development.
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Affiliation(s)
- C A Mueller
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.
| | - J Eme
- Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada.
| | - W W Burggren
- Department of Biological Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203, USA.
| | - R D Roghair
- Stead Family Department of Pediatrics, University of Iowa, 1270 CBRB JPP, Iowa City, IA 52242, USA.
| | - S D Rundle
- Marine Biology and Ecology Research Centre, Plymouth University, 611 Davy Building Drake Circus, Plymouth, Devon PL4 8AA, UK.
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