1
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Méndez-Narváez J, Warkentin KM. Early onset of urea synthesis and ammonia detoxification pathways in three terrestrially developing frogs. J Comp Physiol B 2023; 193:523-543. [PMID: 37639061 DOI: 10.1007/s00360-023-01506-4] [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: 11/10/2022] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 08/29/2023]
Abstract
Frogs evolved terrestrial development multiple times, necessitating mechanisms to avoid ammonia toxicity at early stages. Urea synthesis from ammonia is a key adaptation that reduces water dependence after metamorphosis. We tested for early expression and plasticity of enzymatic mechanisms of ammonia detoxification in three terrestrial-breeding frogs: foam-nest-dwelling larvae of Leptodactylus fragilis (Lf) and arboreal embryos of Hyalinobatrachium fleischmanni (Hf) and Agalychnis callidryas (Ac). Activity of two ornithine-urea cycle (OUC) enzymes, arginase and CPSase, and levels of their products urea and CP in tissues were high in Lf regardless of nest hydration, but reduced in experimental low- vs. high-ammonia environments. High OUC activity in wet and dry nests, comparable to that under experimental high ammonia, suggests terrestrial Lf larvae maintain high capacity for urea excretion regardless of their immediate risk of ammonia toxicity. This may aid survival through unpredictably long waiting periods before rain enables their transition to water. Moderate levels of urea and CP were present in Hf and Ac tissues and enzymatic activities were lower than in Lf. In both species, embryos in drying clutches can hatch and enter the water early, behaviorally avoiding ammonia toxicity. Moreover, glutamine synthetase was active in early stages of all three species, condensing ammonia and glutamate to glutamine as another mechanism of detoxification. Enzyme activity appeared highest in Lf, although substrate and product levels were higher in Ac and Lf. Our results reveal that multiple biochemical mechanisms of ammonia detoxification occur in early life stages of anuran lineages that evolved terrestrial development.
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Affiliation(s)
- Javier Méndez-Narváez
- Calima, Fundación para la Investigación de la Biodiversidad y Conservación en el Trópico, Cali, Colombia.
- Department of Biology, Boston University, Boston, MA, USA.
| | - Karen M Warkentin
- Department of Biology, Boston University, Boston, MA, USA
- Smithsonian Tropical Research Institute, Panamá, Republic of Panama
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2
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Bavis RW, Dirstine T, Lachance AD, Jareno A, Reynoso Williams M. Recovery of the biphasic hypoxic ventilatory response in neonatal rats after chronic hyperoxia. Respir Physiol Neurobiol 2023; 307:103973. [DOI: 10.1016/j.resp.2022.103973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/09/2022] [Accepted: 09/25/2022] [Indexed: 10/14/2022]
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3
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Souquet L, Guenser P, Girard C, Mazza M, Rigo M, Goudemand N. Temperature-driven heterochrony as a main evolutionary response to climate changes in conodonts. Proc Biol Sci 2022; 289:20220614. [PMID: 36259210 PMCID: PMC9579755 DOI: 10.1098/rspb.2022.0614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 09/27/2022] [Indexed: 01/17/2023] Open
Abstract
Can we predict the evolutionary response of organisms to climate changes? The direction of greatest intraspecific phenotypic variance is thought to correspond to an 'evolutionary line of least resistance', i.e. a taxon's phenotype is expected to evolve along that general direction, if not constrained otherwise. In particular, heterochrony, whereby the timing or rate of developmental processes are modified, has often been invoked to describe evolutionary trajectories and it may be advantageous to organisms when rapid adaptation is critical. Yet, to date, little is known empirically as to which covariation patterns, whether static allometry, as measured in adult forms only, or ontogenetic allometry, the basis for heterochrony, may be prevalent in what circumstances. Here, we quantify the morphology of segminiplanate conodont elements during two distinct time intervals separated by more than 130 Myr: the Devonian-Carboniferous boundary and the Carnian-Norian boundary (Late Triassic). We evidence that the corresponding species share similar patterns of intraspecific static allometry. Yet, during both crises, conodont evolution was decoupled from this common evolutionary line of least resistance. Instead, it followed heterochrony-like trajectories that furthermore appear as driven by ocean temperature. This may have implications for our interpretation of conodonts' and past marine ecosystems' response to environmental perturbations.
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Affiliation(s)
- Louise Souquet
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
| | - Pauline Guenser
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
- Univ. Lyon, Université Claude Bernard Lyon 1, LEHNA, CNRS UMR 5023, 3-6 rue Raphaël Dubois – Bâtiments Forel, 69622 Villeurbanne Cedex 43
| | | | | | - Manuel Rigo
- Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131 Padova, Italy
| | - Nicolas Goudemand
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
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4
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Haron A, Shinder D, Ruzal M, Druyan S. Post-Hatch Performance of Broilers Following Hypoxic Exposure During Incubation Under Suboptimal Environmental Temperature. Front Physiol 2022; 13:934676. [PMID: 35936895 PMCID: PMC9355520 DOI: 10.3389/fphys.2022.934676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
The modern broiler is selected to exploit its full genetic potential, to sustain a rapid growth rate, and to lower the feed conversion rate (FCR). Recently reported reductions in FCR have been associated with augmented tissue formation at the expense of physiological functions such as thermoregulation. In turn, modern broilers exhibit a relatively low capability to balance energy expenditure under suboptimal ambient temperature. Hypoxic conditions at late incubation stages play a role in reforming metabolic plasticity. This work examined the effect of exposure to 12-h hypoxia (12H; 17% O2) for three consecutive days (from E16 through E18), or continuous hypoxia exposure for 48 h (48H), from E16 through E17, as compared to standard incubation (21% O2) on post-hatch performance of broilers maintained under suboptimal ambient temperatures (cold, hot, and diurnal cyclic ambient temperature). 12H chicks kept under hot ambient temperature had significantly lower body temperature (Tb) as compared to the control chicks. On day 42, both 12H and 48H chicks grown in the cyclic temperature room had significantly lower Tbs than controls. In parallel, from week 4, onward, 12H chicks had a significantly lower FCR than controls, and the 48H chicks demonstrated a lower FCR from week 5 and on. 12H and 48H broilers maintained under diurnal cyclic ambient temperature, exhibited significantly greater relative breast muscle weight, and a similar pattern was found in hypoxic broilers raised under standard and hot ambient temperatures. Hypoxic manipulation affects and create an adaptive bias in allocating metabolic energy between maintenance and growth, thus resulting in improved broiler performance, thermoregulation, and rearing under suboptimal environmental temperature.
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Affiliation(s)
- A. Haron
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon Le Ziyyon, Israel
| | - D. Shinder
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon Le Ziyyon, Israel
| | - M. Ruzal
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon Le Ziyyon, Israel
| | - S. Druyan
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon Le Ziyyon, Israel
- *Correspondence: S. Druyan,
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5
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McAndry C, Collins M, Tills O, Spicer JI, Truebano M. Regulation of gene expression during ontogeny of physiological function in the brackishwater amphipod Gammarus chevreuxi. Mar Genomics 2022; 63:100948. [PMID: 35427917 DOI: 10.1016/j.margen.2022.100948] [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: 12/03/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
Abstract
Embryonic development is a complex process involving the co-ordinated onset and integration of multiple morphological features and physiological functions. While the molecular basis of morphological development in embryos is relatively well known for traditional model species, the molecular underpinning of the development of physiological functions is not. Here, we used global gene expression profiling to investigate the transcriptional changes associated with the development of morphological and physiological function in the amphipod crustacean Gammarus chevreuxi. We compared the transcriptomes at three timepoints during the latter half of development, characterised by different stages of the development of heart form and function: 10 days post fertilisation (dpf, Early: no heart structure visible), 15 dpf (Middle: heart present but not fully functional), and 18 dpf (Late: regular heartbeat). Gene expression profiles differed markedly between developmental stages, likely representing a change in the activity of different processes throughout the latter period of G. chevreuxi embryonic development. Differentially expressed genes belonged to one of three distinct clusters based on their expression patterns across development. One of these clusters, which included key genes relating to cardiac contractile machinery and calcium handling, displayed a pattern of sequential up-regulation throughout the developmental period studied. Further analyses of these transcripts could reveal genes that may influence the onset of a regular heartbeat. We also identified morphological and physiological processes that may occur alongside heart development, such as development of digestive caeca and the cuticle. Elucidating the mechanisms underpinning morphological and physiological development of non-model organisms will support improved understanding of conserved mechanisms, addressing the current phylogenetic gap between relatively well known model species.
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Affiliation(s)
- C McAndry
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - M Collins
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - O Tills
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - J I Spicer
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - M Truebano
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
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Méndez‐Narváez J, Warkentin KM. Reproductive colonization of land by frogs: Embryos and larvae excrete urea to avoid ammonia toxicity. Ecol Evol 2022; 12:e8570. [PMID: 35222954 PMCID: PMC8843769 DOI: 10.1002/ece3.8570] [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: 07/22/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 11/24/2022] Open
Abstract
Vertebrate colonization of land has occurred multiple times, including over 50 origins of terrestrial eggs in frogs. Some environmental factors and phenotypic responses that facilitated these transitions are known, but responses to water constraints and risk of ammonia toxicity during early development are poorly understood. We tested if ammonia accumulation and dehydration risk induce a shift from ammonia to urea excretion during early stages of four anurans, from three origins of terrestrial development. We quantified ammonia and urea concentrations during early development on land, under well‐hydrated and dry conditions. Where we found urea excretion, we tested for a plastic increase under dry conditions and with ammonia accumulation in developmental environments. We assessed the potential adaptive role of urea excretion by comparing ammonia tolerance measured in 96h‐LC50 tests with ammonia levels in developmental environments. Ammonia accumulated in foam nests and perivitelline fluid, increasing over development and reaching higher concentrations under dry conditions. All four species showed high ammonia tolerance, compared to fishes and aquatic‐breeding frogs. Both nest‐dwelling larvae of Leptodactylus fragilis and late embryos of Hyalinobatrachium fleischmanni excreted urea, showing a plastic increase under dry conditions. These two species can develop the longest on land and urea excretion appears adaptive, preventing their exposure to potentially lethal levels of ammonia. Neither late embryos of Agalychnis callidryas nor nest‐dwelling larvae of Engystomops pustulosus experienced toxic ammonia levels under dry conditions, and neither excreted urea. Our results suggest that an early onset of urea excretion, its increase under dry conditions, and elevated ammonia tolerance can all help prevent ammonia toxicity during terrestrial development. High ammonia represents a general risk for development which may be exacerbated as climate change increases dehydration risk for terrestrial‐breeding frogs. It may also be a cue that elicits adaptive physiological responses during early development.
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Affiliation(s)
- Javier Méndez‐Narváez
- Department of Biology Boston University Boston Massachusetts USA
- Calima Fundación para la Investigación de la Biodiversidad y Conservación en el Trópico Cali Colombia
| | - Karen M. Warkentin
- Department of Biology Boston University Boston Massachusetts USA
- Smithsonian Tropical Research Institute Panama Republic of Panama
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7
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Burggren W. Developmental Physiology: Grand Challenges. Front Physiol 2021; 12:706061. [PMID: 34177630 PMCID: PMC8225327 DOI: 10.3389/fphys.2021.706061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 12/26/2022] Open
Affiliation(s)
- Warren Burggren
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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8
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Haron A, Ruzal M, Shinder D, Druyan S. Hypoxia during incubation and its effects on broiler's embryonic development. Poult Sci 2021; 100:100951. [PMID: 33652530 PMCID: PMC7936217 DOI: 10.1016/j.psj.2020.12.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 12/06/2020] [Accepted: 12/15/2020] [Indexed: 12/03/2022] Open
Abstract
In all vertebrates, hypoxia plays an important role in fetal development, driving vasculogenesis, angiogenesis, hematopoiesis, and chondrogenesis. Therefore, the ability to sense and respond to changes in the availability of oxygen (O2) is crucial for normal embryonic development as well as for developmental plasticity. Moderate levels of hypoxia trigger a regulated process which leads to adaptive responses. Regulation of angiogenesis by hypoxia is an important component of homeostatic control mechanisms that link the cardio-pulmonary-vascular O2 supply to metabolic demands in local tissues. Hypoxia leads to the activation of genes that are important for cell and tissue adaptation to low O2 conditions, such as hypoxia-inducible factor 1. Previous studies have shown a dose-response effect to hypoxia in chicken embryos, with lower and/or prolonged O2 levels affecting multiple mechanisms and providing a spectrum of responses that facilitate the ability to maintain O2 demand despite environmental hypoxia. In chicken embryos, mild to extreme hypoxia during embryogenesis improves chorioallantoic membrane and cardiovascular development, resulting in an increase in O2 carrying capacity and leading to developmental plasticity that may affect post-hatch chick performance and improve adaptation to additional environmental stresses at suboptimal environmental conditions.
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Affiliation(s)
- Amit Haron
- Institute of Animal Science, Agricultural Research Organization (ARO), The Volcani Center, Rishon Le Ziyyon 15159, Israel; Faculty of Agriculture Food and Environment, The Hebrew University, Rehovot 76100, Israel
| | - Mark Ruzal
- Institute of Animal Science, Agricultural Research Organization (ARO), The Volcani Center, Rishon Le Ziyyon 15159, Israel
| | - Dmitry Shinder
- Institute of Animal Science, Agricultural Research Organization (ARO), The Volcani Center, Rishon Le Ziyyon 15159, Israel
| | - Shelly Druyan
- Institute of Animal Science, Agricultural Research Organization (ARO), The Volcani Center, Rishon Le Ziyyon 15159, Israel.
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9
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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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10
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Hyeun-Ji L, Rendón MÁ, Liedtke HC, Gomez-Mestre I. Shifts in the developmental rate of spadefoot toad larvae cause decreased complexity of post-metamorphic pigmentation patterns. Sci Rep 2020; 10:19624. [PMID: 33184389 PMCID: PMC7665075 DOI: 10.1038/s41598-020-76578-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/27/2020] [Indexed: 11/18/2022] Open
Abstract
Amphibian larvae are plastic organisms that can adjust their growth and developmental rates to local environmental conditions. The consequences of such developmental alterations have been studied in detail, both at the phenotypic and physiological levels. While largely unknown, it is of great importance to assess how developmental alterations affect the pigmentation pattern of the resulting metamorphs, because pigmentation is relevant for communication, mate choice, and camouflage and hence influences the overall fitness of the toads. Here we quantify the variation in several aspects of the pigmentation pattern of juvenile spadefoot toads experimentally induced to accelerate their larval development in response to decreased water level. It is known that induced developmental acceleration comes at the cost of reduced size at metamorphosis, higher metabolic rate, and increased oxidative stress. In this study, we show that spadefoot toads undergoing developmental acceleration metamorphosed with a less complex, more homogeneous, darker dorsal pattern consisting of continuous blotches, compared to the more contrasted pattern with segregated blotches and higher fractal dimension in normally developing individuals, and at a smaller size. We also observed a marked effect of population of origin in the complexity of the pigmentation pattern. Complexity of the post-metamorphic dorsal pigmentation could therefore be linked to pre-metamorphic larval growth and development.
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Affiliation(s)
- Lee Hyeun-Ji
- Ecology, Evolution, and Development Group, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain
- Department of Wetland Ecology, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain
| | - Miguel Ángel Rendón
- Department of Wetland Ecology, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain
| | - Hans Christoph Liedtke
- Ecology, Evolution, and Development Group, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain
- Department of Wetland Ecology, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain
| | - Ivan Gomez-Mestre
- Ecology, Evolution, and Development Group, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain.
- Department of Wetland Ecology, Doñana Biological Station, Consejo Superior de Investigaciones Científicas, 41092, Seville, Spain.
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11
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McCoy JCS, Spicer JI, Tills O, Rundle SD. Both maternal and embryonic exposure to mild hypoxia influence embryonic development of the intertidal gastropod Littorina littorea. J Exp Biol 2020; 223:jeb221895. [PMID: 32843360 DOI: 10.1242/jeb.221895] [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: 01/17/2020] [Accepted: 08/17/2020] [Indexed: 11/20/2022]
Abstract
There is growing evidence that maternal exposure to environmental stressors can alter offspring phenotype and increase fitness. Here, we investigate the relative and combined effects of maternal and developmental exposure to mild hypoxia (65 and 74% air saturation, respectively) on the growth and development of embryos of the marine gastropod Littorina littorea Differences in embryo morphological traits were driven by the developmental environment, whereas the maternal environment and interactive effects of maternal and developmental environment were the main driver of differences in the timing of developmental events. While developmental exposure to mild hypoxia significantly increased the area of an important respiratory organ, the velum, it significantly delayed hatching of veliger larvae and reduced their size at hatching and overall survival. Maternal exposure had a significant effect on these traits, and interacted with developmental exposure to influence the time of appearance of morphological characters, suggesting that both are important in affecting developmental trajectories. A comparison between embryos that successfully hatched and those that died in mild hypoxia revealed that survivors exhibited hypertrophy in the velum and associated pre-oral cilia, suggesting that these traits are linked with survival in low-oxygen environments. We conclude that both maternal and developmental environments shape offspring phenotype in a species with a complex developmental life history, and that plasticity in embryo morphology arising from exposure to even small reductions in oxygen tensions affects the hatching success of these embryos.
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Affiliation(s)
- James C S McCoy
- Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - John I Spicer
- Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - Oliver Tills
- Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
| | - Simon D Rundle
- Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
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12
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Pinette M, Bavis RW. Influence of chronic hyperoxia on the developmental time course of the hypoxic ventilatory response relative to other traits in rats. Respir Physiol Neurobiol 2020; 280:103483. [PMID: 32593590 DOI: 10.1016/j.resp.2020.103483] [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: 04/06/2020] [Revised: 06/03/2020] [Accepted: 06/22/2020] [Indexed: 10/24/2022]
Abstract
Newborn mammals exhibit a biphasic hypoxic ventilatory response (HVR) in which an initial increase in ventilation is followed by a decline back toward baseline levels. The magnitude of the secondary decline diminishes with postnatal age, but this transition occurs earlier in rat pups reared in moderate hyperoxia. This pattern is consistent with heterokairy, a form of developmental plasticity in which environmental factors alter the timing of developmental events. The present study investigated whether this plasticity is specific to the HVR or if hyperoxia instead accelerates overall development. Rat pups reared in 60 % O2 (Hyperoxia) exhibited a less biphasic ventilatory response to 12 % O2 than pups reared in 21 % O2 (Control) at 4 days of age (P4) and transitioned to a sustained HVR by P10-11; Control rats exhibited a biphasic HVR at both ages. However, the average ages at which pups attained other key developmental milestones (i.e., fur development at P5, incisor eruption at P9, and eye opening at P15) were similar between treatment groups. Moreover, growth rates and maturation of the metabolic response to cooling were not accelerated, and may have been delayed slightly, relative to Control rats. For example, the capacity for pups to increase their metabolic rate at low ambient temperatures increased with age, but this thermogenic capacity tended to be reduced in Hyperoxia pups at both P4 and P10-11 (i.e., lower CO2 production rates below the lower critical temperature). Collectively, these data support the conclusion that hyperoxia specifically advances the age at which rat pups exhibit a sustained HVR, altering the relative timing of developmental events rather than compressing the entire period of development.
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Affiliation(s)
| | - Ryan W Bavis
- Department of Biology, Bates College, Lewiston, ME, 04240, USA.
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13
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Abstract
Air-breathing animals do not experience hyperoxia (inspired O2 > 21%) in nature, but preterm and full-term infants often experience hyperoxia/hyperoxemia in clinical settings. This article focuses on the effects of normobaric hyperoxia during the perinatal period on breathing in humans and other mammals, with an emphasis on the neural control of breathing during hyperoxia, after return to normoxia, and in response to subsequent hypoxic and hypercapnic challenges. Acute hyperoxia typically evokes an immediate ventilatory depression that is often, but not always, followed by hyperpnea. The hypoxic ventilatory response (HVR) is enhanced by brief periods of hyperoxia in adult mammals, but the limited data available suggest that this may not be the case for newborns. Chronic exposure to mild-to-moderate levels of hyperoxia (e.g., 30-60% O2 for several days to a few weeks) elicits several changes in breathing in nonhuman animals, some of which are unique to perinatal exposures (i.e., developmental plasticity). Examples of this developmental plasticity include hypoventilation after return to normoxia and long-lasting attenuation of the HVR. Although both peripheral and CNS mechanisms are implicated in hyperoxia-induced plasticity, it is particularly clear that perinatal hyperoxia affects carotid body development. Some of these effects may be transient (e.g., decreased O2 sensitivity of carotid body glomus cells) while others may be permanent (e.g., carotid body hypoplasia, loss of chemoafferent neurons). Whether the hyperoxic exposures routinely experienced by human infants in clinical settings are sufficient to alter respiratory control development remains an open question and requires further research. © 2020 American Physiological Society. Compr Physiol 10:597-636, 2020.
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Affiliation(s)
- Ryan W Bavis
- Department of Biology, Bates College, Lewiston, Maine, USA
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14
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Ventilatory and carotid body responses to acute hypoxia in rats exposed to chronic hypoxia during the first and second postnatal weeks. Respir Physiol Neurobiol 2020; 275:103400. [PMID: 32006667 DOI: 10.1016/j.resp.2020.103400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/20/2019] [Accepted: 01/27/2020] [Indexed: 01/24/2023]
Abstract
Chronic hypoxia (CH) during postnatal development causes a blunted hypoxic ventilatory response (HVR) in neonatal mammals. The magnitude of the HVR generally increases with age, so CH could blunt the HVR by delaying this process. Accordingly, we predicted that CH would have different effects on the respiratory control of neonatal rats if initiated at birth versus initiated later in postnatal development (i.e., after the HVR has had time to mature). Rats had blunted ventilatory and carotid body responses to hypoxia whether CH (12 % O2) occurred for the first postnatal week (P0 to P7) or second postnatal week (P7 to P14). However, if initiated at P0, CH also caused the HVR to retain the "biphasic" shape characteristic of newborn mammals; CH during the second postnatal week did not result in a biphasic HVR. CH from birth delayed the transition from a biphasic HVR to a sustained HVR until at least P9-11, but the HVR attained a sustained (albeit blunted) phenotype by P13-15. Since delayed maturation of the HVR did not completely explain the blunted HVR, we tested the alternative hypothesis that the blunted HVR was caused by an inflammatory response to CH. Daily administration of the anti-inflammatory drug ibuprofen (4 mg kg-1, i.p.) did not alter the effects of CH on the HVR. Collectively, these data suggest that CH blunts the HVR in neonatal rats by impairing carotid body responses to hypoxia and by delaying (but not preventing) postnatal maturation of the biphasic HVR. The mechanisms underlying this plasticity require further investigation.
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15
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Leung JYS, McAfee D. Stress across life stages: Impacts, responses and consequences for marine organisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 700:134491. [PMID: 31629264 DOI: 10.1016/j.scitotenv.2019.134491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/10/2019] [Accepted: 09/15/2019] [Indexed: 06/10/2023]
Abstract
Population dynamics of marine organisms are strongly driven by their survival in early life stages. As life stages are tightly linked, environmental stress experienced by organisms in the early life stage can worsen their performance in the subsequent life stage (i.e. carry-over effect). However, stressful events can be ephemeral and hence organisms may be able to counter the harmful effects of transient stress. Here, we analysed the published data to examine the relative strength of carry-over effects on the juvenile growth of marine organisms, caused by different stressors (hypoxia, salinity, starvation, ocean acidification and stress-induced delayed metamorphosis) confronted in their larval stage. Based on 31 relevant published studies, we revealed that food limitation had the greatest negative carry-over effect on juvenile growth. In the laboratory, we tested the effects of short-term early starvation and hypoxia on the larval growth and development of a model organism, polychaete Hydroides elegans, and assessed whether the larvae can accommodate the early stress to maintain their performance as juveniles (settlement and juvenile growth). Results showed that early starvation for 3 days (∼50% of normal larval period) retarded larval growth and development, leading to subsequent reduced settlement rate and juvenile growth. When the starvation period decreased to 1 day, however, the larvae could recover from early starvation through compensatory growth and performed normal as juveniles (c.f. control). Early exposure to hypoxia for 3 days did not affect larval growth (body length) and juvenile growth (tube length), but caused malformation of larvae and reduced settlement rate. We conclude that the adverse effects of transient stress can be carried across life stages (e.g. larval to juvenile stage), but depend on the duration of stressful events relative to larval period. As carry-over effects are primarily driven by energy acquisition, how food availability varies over time and space is fundamental to the population dynamics of marine organisms.
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Affiliation(s)
- Jonathan Y S Leung
- Faculty of Materials and Energy, Southwest University, Chongqing 400715, China; School of Biological Sciences, The University of Adelaide, Adelaide 5005, Australia; Department of Biology and Chemistry, City University of Hong Kong, Hong Kong Special Administrative Region.
| | - Dominic McAfee
- School of Biological Sciences, The University of Adelaide, Adelaide 5005, Australia
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Vagner M, Zambonino-Infante JL, Mazurais D. Fish facing global change: are early stages the lifeline? MARINE ENVIRONMENTAL RESEARCH 2019; 147:159-178. [PMID: 31027942 DOI: 10.1016/j.marenvres.2019.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 04/09/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
The role of phenotypic plasticity in the acclimation and adaptive potential of an organism to global change is not currently accounted for in prediction models. The high plasticity of marine fishes is mainly attributed to their early stages, during which morphological, structural and behavioural functions are particularly sensitive to environmental constraints. This developmental plasticity can determine later physiological performances and fitness, and may further affect population dynamics and ecosystem functioning. This review asks the essential question of what role early stages play in the ability of fish to later cope with the effects of global change, considering three key environmental factors (temperature, hypoxia and acidification). After having identified the carry-over effects of early exposure reported in the literature, we propose areas that we believe warrant the most urgent attention for further research to better understand the role of developmental plasticity in the responses of marine organisms to global change.
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Affiliation(s)
- Marie Vagner
- CNRS, UMR 7266 LIENSs, Institut du littoral et de l'environnement, 2 rue Olympe de Gouges, 17000, La Rochelle, France.
| | | | - David Mazurais
- Ifremer, UMR 6539 LEMAR, ZI pointe du diable, 29280, Plouzané, France
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Physiological effects of dissolved oxygen are stage-specific in incubating Atlantic salmon (Salmo salar). J Comp Physiol B 2019; 189:109-120. [PMID: 30603847 DOI: 10.1007/s00360-018-1199-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 12/04/2018] [Accepted: 12/12/2018] [Indexed: 01/07/2023]
Abstract
Oxygen availability is highly variable during salmonid incubation in natural redds and also in aquaculture incubation systems. Hypoxia generally decreases growth and aerobic metabolism prior to hatching, in parallel with eliciting physiological modifications that enhance oxygen delivery. However, it is less-well known whether developmental hyperoxia can drive the opposite effect. Moreover, there is insufficient understanding of stage-specific developmental windows during which ambient oxygen availability may be of greater or lesser impact to incubating embryos. Here, we tested the effects of hypoxia (50% dissolved oxygen: DO, % air saturation) and hyperoxia (150% DO) on the growth, routine aerobic metabolism ([Formula: see text]) and hypoxia tolerance (O2crit) of Atlantic salmon (Salmo salar) during seven developmental windows throughout incubation. Embryos exposed to hyperoxia (150% DO) did not differ from the normoxic group in growth, [Formula: see text] or O2crit at any developmental window. In contrast, embryos exposed to hypoxia grew slower and had a lower [Formula: see text], but had higher hypoxia tolerance (lower O2crit) than normoxic and hyperoxic counterparts. Interestingly, these differences were only apparent when the embryos were measured prior to hatching. Larvae (alevins) incubated in hypoxia following hatching grew similarly to normoxia-incubated alevins. Our results provide evidence that Atlantic salmon embryos are most sensitive to hypoxia prior to hatching, probably due to increasing (absolute) oxygen requirements concurrent with restricted oxygen diffusion through the egg. Moreover, the similarities between normoxia- and hyperoxia-incubated salmon demonstrate that embryos are not oxygen-limited under normoxic conditions.
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Mendez-Sanchez JF, Burggren WW. Cardiorespiratory physiological phenotypic plasticity in developing air-breathing anabantid fishes ( Betta splendens and Trichopodus trichopterus). Physiol Rep 2018; 5:5/15/e13359. [PMID: 28778991 PMCID: PMC5555888 DOI: 10.14814/phy2.13359] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 06/24/2017] [Indexed: 11/30/2022] Open
Abstract
Developmental plasticity of cardiorespiratory physiology in response to chronic hypoxia is poorly understood in larval fishes, especially larval air‐breathing fishes, which eventually in their development can at least partially “escape” hypoxia through air breathing. Whether the development air breathing makes these larval fishes less or more developmentally plastic than strictly water breathing larval fishes remains unknown. Consequently, developmental plasticity of cardiorespiratory physiology was determined in two air‐breathing anabantid fishes (Betta splendens and Trichopodus trichopterus). Larvae of both species experienced an hypoxic exposure that mimicked their natural environmental conditions, namely chronic nocturnal hypoxia (12 h at 17 kPa or 14 kPa), with a daily return to diurnal normoxia. Chronic hypoxic exposures were made from hatching through 35 days postfertilization, and opercular and heart rates measured as development progressed. Opercular and heart rates in normoxia were not affected by chronic nocturnal hypoxic. However, routine oxygen consumption M˙O2 (~4 μmol·O2/g per hour in normoxia in larval Betta) was significantly elevated by chronic nocturnal hypoxia at 17 kPa but not by more severe (14 kPa) nocturnal hypoxia. Routine M˙O2 in Trichopodus (6–7 μmol·O2/g per hour), significantly higher than in Betta, was unaffected by either level of chronic hypoxia. PCrit, the PO2 at which M˙O2 decreases as ambient PO2 falls, was measured at 35 dpf, and decreased with increasing chronic hypoxia in Betta, indicating a large, relatively plastic hypoxic tolerance. However, in contrast, PCrit in Trichopodus increased as rearing conditions grew more hypoxic, suggesting that hypoxic acclimation led to lowered hypoxic resistance. Species‐specific differences in larval physiological developmental plasticity thus emerge between the relatively closely related Betta and Trichopodus. Hypoxic rearing increased hypoxic tolerance in Betta, which inhabits temporary ponds with nocturnal hypoxia. Trichopodus, inhabiting more permanent oxygenated bodies of water, showed few responses to hypoxia, reflecting a lower degree of developmental phenotypic plasticity.
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Affiliation(s)
- Jose F Mendez-Sanchez
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, Texas .,Department of Biology, Autonomous University of the State of Mexico, Toluca, State of Mexico, Mexico
| | - Warren W Burggren
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, Texas
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Burggren W. Developmental phenotypic plasticity helps bridge stochastic weather events associated with climate change. ACTA ACUST UNITED AC 2018; 221:221/9/jeb161984. [PMID: 29748332 DOI: 10.1242/jeb.161984] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The slow, inexorable rise in annual average global temperatures and acidification of the oceans are often advanced as consequences of global change. However, many environmental changes, especially those involving weather (as opposed to climate), are often stochastic, variable and extreme, particularly in temperate terrestrial or freshwater habitats. Moreover, few studies of animal and plant phenotypic plasticity employ realistic (i.e. short-term, stochastic) environmental change in their protocols. Here, I posit that the frequently abrupt environmental changes (days, weeks, months) accompanying much longer-term general climate change (e.g. global warming over decades or centuries) require consideration of the true nature of environmental change (as opposed to statistical means) coupled with an expansion of focus to consider developmental phenotypic plasticity. Such plasticity can be in multiple forms - obligatory/facultative, beneficial/deleterious - depending upon the degree and rate of environmental variability at specific points in organismal development. Essentially, adult phenotypic plasticity, as important as it is, will be irrelevant if developing offspring lack sufficient plasticity to create modified phenotypes necessary for survival.
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Affiliation(s)
- Warren Burggren
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX 76205, USA
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20
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Dubansky B, Verbeck G, Mach P, Burggren W. Methodology for exposing avian embryos to quantified levels of airborne aromatic compounds associated with crude oil spills. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2018; 58:163-169. [PMID: 29408758 DOI: 10.1016/j.etap.2018.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/09/2018] [Indexed: 06/07/2023]
Abstract
Oil spills on birds and other organisms have focused primarily on direct effects of oil exposure through ingestion or direct body fouling. Little is known of indirect effects of airborne volatiles from spilled oil, especially on vulnerable developing embryos within the bird egg. Here a technique is described for exposing bird embryos in the egg to quantifiable amounts of airborne volatile toxicants from Deepwater Horizon crude oil. A novel membrane inlet mass spectrometry system was used to measure major classes of airborne oil-derived toxicants and correlate these exposures with biological endpoints. Exposure induced a reduction in platelet number and increase in osmolality of the blood of embryos of the chicken (Gallus gallus). Additionally, expression of cytochrome P4501A, a protein biomarker of oil exposure, occurred in renal, pulmonary, hepatic and vascular tissues. These data confirm that this system for generating and measuring airborne volatiles can be used for future in-depth analysis of the toxicity of volatile organic compounds in birds and potentially other terrestrial organisms.
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Affiliation(s)
- Benjamin Dubansky
- University of North Texas, Department of Biological Sciences, Developmental Integrative Biology Cluster, 1155 Union Circle, Denton, TX, 76203, United States.
| | - Guido Verbeck
- University of North Texas, Department of Chemistry and Biochemistry, Laboratory for Imaging Mass Spectrometry, 1417 Hickory Street, Denton, TX, 76203, United States
| | - Phillip Mach
- University of North Texas, Department of Chemistry and Biochemistry, Laboratory for Imaging Mass Spectrometry, 1417 Hickory Street, Denton, TX, 76203, United States; Aberdeen Proving Ground, 5183 Balckhawk Rd, E3150, Gunpowder, MD, 21010, United States
| | - Warren Burggren
- University of North Texas, Department of Biological Sciences, Developmental Integrative Biology Cluster, 1155 Union Circle, Denton, TX, 76203, United States
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Augustine S. Maturity as quantifier for physiological time: Comment on "Physics of metabolic organization" by Marko Jusup et al. Phys Life Rev 2017; 20:40-42. [PMID: 28094143 DOI: 10.1016/j.plrev.2017.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/11/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Starrlight Augustine
- Akvaplan-niva, Fram High North Research Centre for Climate & Environment, 9296 Tromsø, Norway.
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22
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Developmental plasticity in the neural control of breathing. Exp Neurol 2017; 287:176-191. [DOI: 10.1016/j.expneurol.2016.05.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/13/2016] [Accepted: 05/26/2016] [Indexed: 12/14/2022]
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Rundle SD, Spicer JI. Heterokairy: a significant form of developmental plasticity? Biol Lett 2016; 12:20160509. [PMID: 27624796 PMCID: PMC5046929 DOI: 10.1098/rsbl.2016.0509] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/24/2016] [Indexed: 12/15/2022] Open
Abstract
There is a current surge of research interest in the potential role of developmental plasticity in adaptation and evolution. Here we make a case that some of this research effort should explore the adaptive significance of heterokairy, a specific type of plasticity that describes environmentally driven, altered timing of development within a species. This emphasis seems warranted given the pervasive occurrence of heterochrony, altered developmental timing between species, in evolution. We briefly review studies investigating heterochrony within an adaptive context across animal taxa, including examples that explore links between heterokairy and heterochrony. We then outline how sequence heterokairy could be included within the research agenda for developmental plasticity. We suggest that the study of heterokairy may be particularly pertinent in (i) determining the importance of non-adaptive plasticity, and (ii) embedding concepts from comparative embryology such as developmental modularity and disassociation within a developmental plasticity framework.
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Affiliation(s)
- S D Rundle
- Marine Biology and Ecology Research Centre, Plymouth University, Plymouth, UK
| | - J I Spicer
- Marine Biology and Ecology Research Centre, Plymouth University, Plymouth, UK
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24
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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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Rudin-Bitterli TS, Spicer JI, Rundle SD. Differences in the timing of cardio-respiratory development determine whether marine gastropod embryos survive or die in hypoxia. J Exp Biol 2016; 219:1076-85. [DOI: 10.1242/jeb.134411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 01/31/2016] [Indexed: 11/20/2022]
Abstract
Physiological plasticity of early developmental stages is a key way by which organisms can survive and adapt to environmental change. We investigated developmental plasticity of aspects of the cardio-respiratory physiology of encapsulated embryos of a marine, gastropod Littorina obtusata surviving exposure to moderate hypoxia (pO2=8 kPa) and compared the development of these survivors with that of individuals that died before hatching. Individuals surviving hypoxia exhibited a slower rate of development and altered ontogeny of cardio-respiratory structure and function compared with normoxic controls (pO2>20 kPa). The onset and development of the larval and adult hearts were delayed in chronological time in hypoxia, but both organs appeared earlier in developmental time and cardiac activity rates were greater. The velum, a transient, ‘larval’ organ thought to play a role in gas exchange, was larger in hypoxia but developed more slowly (in chronological time), and velar cilia-driven, rotational activity was lower. Despite these effects of hypoxia, 38% of individuals survived to hatching. Compared with those embryos that died during development, these surviving embryos had advanced expression of adult structures, i.e. a significantly earlier occurrence and greater activity of their adult heart and larger shells. In contrast, embryos that died retained larval cardio-respiratory features (the velum and larval heart) for longer in chronological time. Surviving embryos came from eggs with significantly higher albumen provisioning than those that died, suggesting an energetic component for advanced development of adult traits.
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Affiliation(s)
- T. S. Rudin-Bitterli
- Marine Biology and Ecology Research Centre, Plymouth University, Plymouth PL4 8AA, UK
| | - J. I. Spicer
- Marine Biology and Ecology Research Centre, Plymouth University, Plymouth PL4 8AA, UK
| | - S. D. Rundle
- Marine Biology and Ecology Research Centre, Plymouth University, Plymouth PL4 8AA, UK
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26
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Touchon JC, McCoy MW, Landberg T, Vonesh JR, Warkentin KM. Putting μ/gin a new light: plasticity in life history switch points reflects fine-scale adaptive responses. Ecology 2015; 96:2192-202. [DOI: 10.1890/14-1301.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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27
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Burggren WW, Mueller CA. Developmental Critical Windows and Sensitive Periods as Three-Dimensional Constructs in Time and Space. Physiol Biochem Zool 2015; 88:91-102. [DOI: 10.1086/679906] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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28
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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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Varela-Lasheras I, Van Dooren TJM. Desiccation plasticity in the embryonic life histories of non-annual rivulid species. EvoDevo 2014; 5:16. [PMID: 24817996 PMCID: PMC4016651 DOI: 10.1186/2041-9139-5-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/14/2014] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Diapause is a developmental arrest present in annual killifish, whose eggs are able to survive long periods of desiccation when the temporary ponds they inhabit dry up. Diapause can occur in three different developmental stages. These differ, within and between species, in their responsiveness to different environmental cues. A role of developmental plasticity and genetic assimilation in diapause evolution has been previously suggested but not experimentally explored. We investigated whether plastic developmental delays or arrests provoked by an unusual and extreme environment could be the ancestral condition for diapause. This would be in agreement with plasticity evolution playing a role in the emergence of diapause in this group. We have used a comparative experimental approach and exposed embryos of non-annual killifish belonging to five different species from the former genus Rivulus to brief periods of desiccation. We have estimated effects on developmental and mortality rates during and after the desiccation treatment. RESULTS Embryos of these non-annual rivulids decreased their developmental rates in early stages of development in response to desiccation and this effect persisted after the treatment. Two pairs of two different species had sufficient sample sizes to investigate rates of development in later stages well. In one of these, we found cohorts of embryos in the latest stages of development that did not hatch over a period of more than 1 month without mortality. Several properties of this arrest are also used to characterize diapause III in annual killifish. Such a cohort is present in control conditions and increases in frequency in the desiccation treatment. CONCLUSIONS The presence of plasticity for developmental timing and a prolonged developmental arrest in non-annual rivulids, suggest that a plastic developmental delay or diapause might have been present in the shared ancestor of annual and non-annual South American killifish and that the evolution of plasticity could have played a role in the emergence of the diapauses. Further comparative experimental studies and field research are needed to better understand how diapause and its plasticity evolved in this group.
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Affiliation(s)
- Irma Varela-Lasheras
- Naturalis Biodiversity Center, Darwinweg 2, Leiden 2333 CR, The Netherlands
- Current address: Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Tom JM Van Dooren
- Naturalis Biodiversity Center, Darwinweg 2, Leiden 2333 CR, The Netherlands
- CNRS/UPMC/UPEC/UPD/IRD/INRA–UMR 7618 Institute of Ecology and Environmental Sciences Paris (iEES), Université Pierre et Marie Curie, Case 237, 7 Quai St Bernard, 75005 Paris, France
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30
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Mendez-Sanchez JF, Burggren WW. Environmental modulation of the onset of air breathing and survival of Betta splendens and Trichopodus trichopterus. JOURNAL OF FISH BIOLOGY 2014; 84:794-807. [PMID: 24502248 DOI: 10.1111/jfb.12322] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 12/18/2013] [Indexed: 06/03/2023]
Abstract
The effect of hypoxia on air-breathing onset and survival was determined in larvae of the air-breathing fishes, the three spot gourami Trichopodus trichopterus and the Siamese fighting fish Betta splendens. Larvae were exposed continuously or intermittently (12 h nightly) to an oxygen partial pressure (PO2 ) of 20, 17 and 14 kPa from 1 to 40 days post-fertilization (dpf). Survival and onset of air breathing were measured daily. Continuous normoxic conditions produced a larval survival rate of 65-75% for B. splendens and 15-30% for T. trichopterus, but all larvae of both species died at 9 dpf in continuous hypoxia conditions. Larvae under intermittent (nocturnal) hypoxia showed a 15% elevated survival rate in both species. The same conditions altered the onset of air breathing, advancing onset by 4 days in B. splendens and delaying onset by 9 days in T. trichopterus. These interspecific differences were attributed to air-breathing characteristics: B. splendens was a non-obligatory air breather after 36 dpf, whereas T. trichopterus was an obligatory air breather after 32 dpf.
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Affiliation(s)
- J F Mendez-Sanchez
- University of North Texas, Department of Biological Sciences, Denton, TX 76203, U.S.A.; Departamento de Biología, Universidad Autónoma del Estado de México, Instituto Literario 100, Centro, Toluca, Estado de México 50120, México
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Wenger AS, McCormick MI, Endo GGK, McLeod IM, Kroon FJ, Jones GP. Suspended sediment prolongs larval development in a coral reef fish. ACTA ACUST UNITED AC 2013; 217:1122-8. [PMID: 24311818 DOI: 10.1242/jeb.094409] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Increasing sediment input into coastal environments is having a profound influence on shallow marine habitats and associated species. Coral reef ecosystems appear to be particularly sensitive, with increased sediment deposition and re-suspension being associated with declines in the abundance and diversity of coral reef fishes. While recent research has demonstrated that suspended sediment can have negative impacts on post-settlement coral reef fishes, its effect on larval development has not been investigated. In this study, we tested the effects of different levels of suspended sediment on larval growth and development time in Amphiprion percula, a coral reef damselfish. Larvae were subjected to four experimental concentrations of suspended sediment spanning the range found around coastal coral reefs (0-45 mg l(-1)). Larval duration was significantly longer in all sediment treatments (12 days) compared with the average larval duration in the control treatment (11 days). Approximately 75% of the fish in the control had settled by day 11, compared with only 40-46% among the sediment treatments. In the highest sediment treatment, some individuals had a larval duration twice that of the median duration in the control treatment. Unexpectedly, in the low sediment treatment, fish at settlement were significantly longer and heavier compared with fish in the other treatments, suggesting delayed development was independent of individual condition. A sediment-induced extension of the pelagic larval stage could significantly reduce numbers of larvae competent to settle and, in turn, have major effects on adult population dynamics.
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Affiliation(s)
- Amelia S Wenger
- School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia
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Bavis RW, DeAngelis KJ, Horowitz TC, Reedich LM, March RJ. Hyperoxia-induced developmental plasticity of the hypoxic ventilatory response in neonatal rats: contributions of glutamate-dependent and PDGF-dependent mechanisms. Respir Physiol Neurobiol 2013; 191:84-94. [PMID: 24284036 DOI: 10.1016/j.resp.2013.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 10/24/2013] [Accepted: 11/18/2013] [Indexed: 10/26/2022]
Abstract
Rats reared in hyperoxia exhibit a sustained (vs. biphasic) hypoxic ventilatory response (HVR) at an earlier age than untreated, Control rats. Given the similarity between the sustained HVR obtained after chronic exposure to developmental hyperoxia and the mature HVR, it was hypothesized that hyperoxia-induced plasticity and normal maturation share common mechanisms such as enhanced glutamate and nitric oxide signaling and diminished platelet-derived growth factor (PDGF) signaling. Rats reared in 21% O2 (Control) or 60% O2 (Hyperoxia) from birth until 4-5 days of age were studied after intraperitoneal injection of drugs targeting these pathways. Hyperoxia rats receiving saline showed a sustained HVR to 12% O2, but blockade of NMDA glutamate receptors (MK-801) restored the biphasic HVR typical of newborn rats. Blockade of PDGF-β receptors (imatinib) had no effect on the pattern of the HVR in Hyperoxia rats, although it attenuated ventilatory depression during the late phase of the HVR in Control rats. Neither nitric oxide synthase inhibitor used in this study (nNOS inhibitor I and l-NAME) altered the pattern of the HVR in Control or Hyperoxia rats. Drug-induced changes in the biphasic HVR were not correlated with changes in metabolic rate. Collectively, these results suggest that developmental hyperoxia hastens the transition from a biphasic to sustained HVR by upregulating glutamate-dependent mechanisms and downregulating PDGF-dependent mechanisms, similar to the changes underlying normal postnatal maturation of the biphasic HVR.
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Affiliation(s)
- Ryan W Bavis
- Department of Biology, Bates College, Lewiston, ME 04240, USA.
| | | | | | - Lisa M Reedich
- Department of Biology, Bates College, Lewiston, ME 04240, USA
| | - Ryan J March
- Department of Biology, Bates College, Lewiston, ME 04240, USA
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Marasco V, Spencer KA, Robinson J, Herzyk P, Costantini D. Developmental post-natal stress can alter the effects of pre-natal stress on the adult redox balance. Gen Comp Endocrinol 2013; 191:239-46. [PMID: 23867229 DOI: 10.1016/j.ygcen.2013.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/27/2013] [Accepted: 07/01/2013] [Indexed: 11/26/2022]
Abstract
Across diverse vertebrate taxa, stressful environmental conditions during development can shape phenotypic trajectories of developing individuals, which, while adaptive in the short-term, may impair health and survival in adulthood. Regardless, the long-lasting benefits or costs of early life stress are likely to depend on the conditions experienced across differing stages of development. Here, we used the Japanese quail (Coturnix coturnix japonica) to experimentally manipulate exposure to stress hormones in developing individuals. We tested the hypothesis that interactions occurring between pre- and post-natal developmental periods can induce long-term shifts on the adult oxidant phenotype in non-breeding sexually mature individuals. We showed that early life stress can induce long-term alterations in the basal antioxidant defences. The magnitude of these effects depended upon the timing of glucocorticoid exposure and upon interactions between the pre- and post-natal stressful stimuli. We also found differences among tissues with stronger effects in the erythrocytes than in the brain in which the long-term effects of glucocorticoids on antioxidant biomarkers appeared to be region-specific. Recent experimental work has demonstrated that early life exposure to stress hormones can markedly reduce adult survival (Monaghan et al., 2012). Our results suggest that long-term shifts in basal antioxidant defences might be one of the potential mechanisms driving such accelerated ageing processes and that post-natal interventions during development may be a potential tool to shape the effects induced by pre-natally glucococorticoid-exposed phenotypes.
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Affiliation(s)
- Valeria Marasco
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
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Crocker CD, Chapman LJ, Martínez ML. Hypoxia-induced plasticity in the metabolic response of a widespread cichlid. Comp Biochem Physiol B Biochem Mol Biol 2013; 166:141-7. [PMID: 23973608 DOI: 10.1016/j.cbpb.2013.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 08/08/2013] [Accepted: 08/15/2013] [Indexed: 10/26/2022]
Abstract
The African cichlid, Pseudocrenilabrus multicolor victoriae is a eurytopic fish that exhibits high levels of developmental plasticity in response to dissolved oxygen availability. In this study, F1 offspring from three sites in the Mpanga River drainage of Western Uganda characterized by different dissolved oxygen (D.O.) regimes were reared under normoxic or hypoxic conditions. After 1 year, enzymes were measured to determine the tissue metabolic capacity of four different tissues: muscle, heart, brain and liver. The enzymes measured were pyruvate kinase [PK], lactate dehydrogenase [LDH], citrate synthase [CS], and cytochrome C oxidase [CCO], and an additional two, malate dehydrogenase (MDH) and fructose 1,6-bisphosphatase (FBPase), were examined in the liver only. Individuals reared under hypoxia exhibited elevated levels of LDH and CCO in the heart; and depressed activity levels of brain CS and liver CCO and MDH relative to normoxia-reared sibs. Results from this study demonstrate that long-term exposure to hypoxia during development can induce changes in the metabolic capacities of P. multicolor. This flexibility may be important in facilitating persistence in variable and/or novel environments, and in the face of increasing global hypoxia.
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Affiliation(s)
- Cindy D Crocker
- Department of Biology, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada
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Johnston EF, Alderman SL, Gillis TE. Chronic hypoxia exposure of trout embryos alters swimming performance and cardiac gene expression in larvae. Physiol Biochem Zool 2013; 86:567-75. [PMID: 23995487 DOI: 10.1086/672012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hypoxia exposure during embryonic development of rainbow trout causes developmental delay and bradycardia and alters the ontogeny of cardiac regulatory control mechanisms. The purpose of this study was to characterize how hypoxia exposure from the day of fertilization until stage 34 (57 d postfertilization) affects the aerobic fitness and growth of the hatched fish at multiple stages. In addition, we characterized the expression of gene transcripts for seven troponin I (TnI) isoforms to examine the effect of hypoxia treatment on cardiac muscle development. Results demonstrate that the critical swimming speed of the hypoxia-exposed fish was significantly less than that of the control group at stage 35 and the fry stage. Growth was reduced in the hypoxia-treated fish between stages 35 and 37, as was the relative lipid content at stage 37. Finally, six TnI isoforms were found in all hearts. One of these isoforms, RTcTnI, decreased in abundance between stage 35 and the fry stage, but hypoxia-exposed fish had higher levels than did controls at the fry stage. The abundance of AScTnI2 was significantly lower in hypoxia-exposed fry fish than in controls. These results indicate that chronic hypoxia exposure during embryonic development has long-term consequences on aerobic fitness, growth, and cardiac gene expression following hatch.
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Affiliation(s)
- Elizabeth F Johnston
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Arrighi JM, Lencer ES, Jukar A, Park D, Phillips PC, Kaplan RH. Daily temperature fluctuations unpredictably influence developmental rate and morphology at a critical early larval stage in a frog. BMC Ecol 2013; 13:18. [PMID: 23641898 PMCID: PMC3653820 DOI: 10.1186/1472-6785-13-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/22/2013] [Indexed: 11/10/2022] Open
Abstract
Background Environmental temperature has profound consequences for early amphibian development and many field and laboratory studies have examined this. Most laboratory studies that have characterized the influence of temperature on development in amphibians have failed to incorporate the realities of diel temperature fluctuations (DTF), which can be considerable for pond-breeding amphibians. Results We evaluated the effects of different ecologically relevant ranges of DTF compared with effects of constant temperatures on development of embryos and larvae of the Korean fire-bellied toad (Bombina orientalis). We constructed thermal reaction norms for developmental stage, snout- vent length, and tail length by fitting a Gompertz-Gaussian function to measurements taken from embryos after 66 hours of development in 12 different constant temperature environments between 14°C and 36°C. We used these reaction norms as null models to test the hypothesis that developmental effects of DTF are more than the sum of average constant temperature effects over the distribution of temperatures experienced. We predicted from these models that growth and differentiation would be positively correlated with average temperature at low levels of DTF but not at higher levels of DTF. We tested our prediction in the laboratory by rearing B. orientalis embryos at three average temperatures (20°C, 24°C, and 28°C) and four levels of thermal variation (0°C, 6°C, 13°C, and 20°C). Several of the observed responses to DTF were significantly different from both predictions of the model and from responses in constant temperature treatments at the same average temperatures. At an average temperature of 24°C, only the highest level of DTF affected differentiation and growth rates, but at both cooler and warmer average temperatures, moderate DTF was enough to slow developmental and tail growth rates. Conclusions These results demonstrate that both the magnitude of DTF range and thermal averages need to be considered simultaneously when parsing the effects of changing thermal environments on complex developmental responses, particularly when they have potential functional and adaptive significance.
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Martin KL, Carter AL. Brave New Propagules: Terrestrial Embryos in Anamniotic Eggs. Integr Comp Biol 2013; 53:233-47. [DOI: 10.1093/icb/ict018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Bianchini K, Wright PA. Hypoxia delays hematopoiesis: retention of embryonic hemoglobin and erythrocytes in larval rainbow trout, Oncorhynchus mykiss, during chronic hypoxia exposure. J Exp Biol 2013; 216:4415-25. [DOI: 10.1242/jeb.083337] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
In rainbow trout development, a switch occurs from high-affinity embryonic hemoglobin (Hb) and round, embryonic erythrocytes to lower-affinity adult Hb and oval, adult erythrocytes. Our study investigated the early ontogeny of rainbow trout blood properties and the hypoxia response. We hypothesized that hypoxia exposure would delay the ontogenetic turnover of Hb and erythrocytes because retention of high-affinity embryonic Hb would facilitate oxygen loading. To test this hypothesis we developed a method of efficiently extracting blood from individual embryos and larvae and optimized several techniques for measuring hematological parameters on microliter (0.5 - 2.0 μl) blood samples. In chronic hypoxia (30% of oxygen saturation), stage-matched embryos and larvae possessed half the Hb concentration, erythrocyte counts, and hematocrit observed in normoxia. Hypoxia-reared larvae also had 3 to 6 fold higher mRNA expression of the embryonic Hb α-1, β-1, and β-2 subunits relative to stage-matched normoxia-reared larvae. Furthermore, in hypoxia the round embryonic erythrocytic shape persisted into later developmental stages. Despite these differences, Hb-oxygen affinity (P50), cooperativity, and the Root effect were unaltered in hypoxia-reared O. mykiss. The data support our hypothesis that chronic hypoxia delays the ontogenetic turnover of Hb and erythrocytes but without the predicted functional consequences (i.e. higher than expected P50). These results also suggest that the Hb-oxygen affinity is protected during development in chronic hypoxia to favour oxygen unloading at the tissues. We conclude that in early trout development, the blood-oxygen transport system responds very differently to chronic hypoxia relative to adults, possibly because respiration depends relatively more on oxygen diffusion than convection.
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Coccimiglio ML, Jonz MG. Serotonergic neuroepithelial cells of the skin in developing zebrafish: morphology, innervation and oxygen-sensitive properties. ACTA ACUST UNITED AC 2012; 215:3881-94. [PMID: 22855620 DOI: 10.1242/jeb.074575] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In teleost fish, O(2) chemoreceptors of the gills (neuroepithelial cells or NECs) initiate cardiorespiratory reflexes during hypoxia. In developing zebrafish, hyperventilatory and behavioural responses to hypoxia are observed before development of gill NECs, indicating that extrabranchial chemoreceptors mediate these responses in embryos. We have characterised a population of cells of the skin in developing zebrafish that resemble O(2)-chemoreceptive gill NECs. Skin NECs were identified by serotonin immunolabelling and were distributed over the entire skin surface. These cells contained synaptic vesicles and were associated with nerve fibres. Skin NECs were first evident in embryos 24-26 h post-fertilisation (h.p.f.), and embryos developed a behavioural response to hypoxia between 24 and 48 h.p.f. The total number of NECs declined with age from approximately 300 cells per larva at 3 days post-fertilisation (d.p.f.) to ~120 cells at 7 d.p.f., and were rarely observed in adults. Acclimation to hypoxia (30 mmHg) or hyperoxia (300 mmHg) resulted in delayed or accelerated development, respectively, of peak resting ventilatory frequency and produced changes in the ventilatory response to hypoxia. In hypoxia-acclimated larvae, the temporal pattern of skin NECs was altered such that the number of cells did not decrease with age. By contrast, hyperoxia produced a more rapid decline in NEC number. The neurotoxin 6-hydroxydopamine degraded catecholaminergic nerve terminals that made contact with skin NECs and eliminated the hyperventilatory response to hypoxia. These results indicate that skin NECs are sensitive to changes in O(2) and suggest that they may play a role in initiating responses to hypoxia in developing zebrafish.
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Orgeig S, Morrison JL, Daniels CB. Prenatal development of the pulmonary surfactant system and the influence of hypoxia. Respir Physiol Neurobiol 2011; 178:129-45. [DOI: 10.1016/j.resp.2011.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 05/19/2011] [Accepted: 05/20/2011] [Indexed: 01/10/2023]
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Spicer JI, Rundle SD, Tills O. Studying the altered timing of physiological events during development: It's about time…or is it? Respir Physiol Neurobiol 2011; 178:3-12. [DOI: 10.1016/j.resp.2011.06.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/03/2011] [Accepted: 06/08/2011] [Indexed: 11/26/2022]
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42
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Moravek CL, Martin KL. Life Goes On: Delayed Hatching, Extended Incubation, and Heterokairy in Development of Embryonic California Grunion, Leuresthes tenuis. COPEIA 2011. [DOI: 10.1643/cg-10-164] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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43
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Miller SC, Gillis TE, Wright PA. The ontogeny of regulatory control of the rainbow trout (Oncorhynchus mykiss) heart and how this is influenced by chronic hypoxia exposure. J Exp Biol 2011; 214:2065-72. [DOI: 10.1242/jeb.054825] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Salmonid embryos develop in cool waters over relatively long periods of time. Interestingly, hypoxic conditions have been found to be relatively common in some nesting sites (redds). The goals of this study were to determine the ontogeny of cardiac regulation in rainbow trout early life stages and how this is influenced by chronic hypoxia. The heart rate response to cholinergic and adrenergic receptor stimulation or inhibition was measured in individuals reared in normoxic (100% O2 saturation) or hypoxic (30% O2 saturation) conditions from fertilization to embryonic stages 22, 26 and 29, and larval stages 30 and 32. In normoxia, heart rate increased in response to β-adrenergic receptor stimulation (isoproterenol) as early as embryonic stage 22, and decreased with the antagonist propranolol after this stage. Cholinergic stimulation (acetylcholine) was ineffective at all stages, but atropine (acetylcholine antagonist) increased heart rate at larval stage 32. This demonstrates that cardiac β-adrenergic receptors are functional at early life stages, while cholinergic receptors are not responsive until after hatching. Collectively, embryos had cardio-acceleration control mechanisms in place just after the heartbeat stage, while cardio-inhibitory control was not functional until after hatching. Chronic hypoxia exposure triggered bradycardia, increased the response to adrenergic stimulation in embryos and larvae, and delayed the onset of cholinergic control in larvae. In non-motile stages, therefore, survival in chronic low oxygen may depend on the ability to alter the cardiac ontogenic program to meet the physiological requirements of the developing fish.
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Affiliation(s)
- Silvana C. Miller
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Todd E. Gillis
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Patricia A. Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
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Martin K, Bailey K, Moravek C, Carlson K. Taking the plunge: California Grunion embryos emerge rapidly with environmentally cued hatching. Integr Comp Biol 2011; 51:26-37. [PMID: 21665921 DOI: 10.1093/icb/icr037] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The process of hatching has been well studied in some model species of teleosts: the medaka Oryzias latipes, the mummichog Fundulus heteroclitus, and the zebrafish Danio rerio. These models are compared to the California Grunion, Leuresthes tenuis that has some unique features of reproduction related to tidal synchrony of spawning and environmentally cued hatching (ECH). During oviposition at spring tides, this marine teleost spawns out of water to bury its clutches on sandy beaches in the high intertidal zone. After embryos of L. tenuis reach hatching competence, hatching can be triggered at any time. Incubation above the water line inhibits hatching until ECH is triggered by rising tides during the following lunar phase, and hatching occurs within a few seconds. We review the embryo's response to environmental cues at hatching and the effects of the surrounding medium on the chorionase and chorion for this form of ECH. Leuresthes tenuis shares some similarities as well as some important differences with the model species. Comparison of hatching across teleostean taxa indicates great variability in stage at hatching and in duration of incubation that suggest hatching plasticity in response to environmental cues may be more widespread than currently appreciated.
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Affiliation(s)
- Karen Martin
- Department of Biology, Pepperdine University, Malibu, CA 90263-4321, USA
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Ho DH, Reed WL, Burggren WW. Egg yolk environment differentially influences physiological and morphological development of broiler and layer chicken embryos. ACTA ACUST UNITED AC 2011; 214:619-28. [PMID: 21270311 DOI: 10.1242/jeb.046714] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Maternal effects are important in epigenetic determination of offspring phenotypes during all life stages. In the chicken (Gallus gallus domesticus), transgenerational transfer of egg yolk factors may set the stage for morphological and physiological phenotypic differences observed among breeds. To investigate the effect of breed-specific yolk composition on embryonic broiler and layer chicken phenotypes, we employed an ex ovo, xenobiotic technique that allowed the transfer of broiler and layer chicken embryos from their natural yolks to novel yolk environments. Embryonic day two broiler embryos developing on broiler yolk culture medium (YCM) had significantly higher heart rates than layer embryos developing on layer YCM (176±7 beats min(-1) and 147±7 beats min(-1), respectively). Broiler embryos developing on layer YCM exhibited heart rates typical of layer embryos developing normally on layer YCM. However, layer embryo heart rates were not affected by development on broiler YCM. Unlike O(2) consumption, development rate and body mass of embryos were significantly affected by exposure to different yolk types, with both broiler and layer embryos displaying traits that reflected yolk source rather than embryo genotype. Analysis of hormone concentrations of broiler and layer egg yolks revealed that testosterone concentrations were higher in broiler yolk (4.63±2.02 pg mg(-1) vs 3.32±1.92 pg mg(-1)), whereas triiodothyronine concentrations were higher in layer yolk (1.05±0.18 pg mg(-1) vs 0.46±0.22 pg mg(-1)). Thus, a complex synergistic effect of breed-specific genotype and yolk environment exists early in chicken development, with yolk thyroid hormone and yolk testosterone as potential mediators of the physiological and morphological effects.
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Affiliation(s)
- Dao H Ho
- Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA.
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Burggren WW, Reyna KS. Developmental trajectories, critical windows and phenotypic alteration during cardio-respiratory development. Respir Physiol Neurobiol 2011; 178:13-21. [PMID: 21596160 DOI: 10.1016/j.resp.2011.05.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/02/2011] [Accepted: 05/03/2011] [Indexed: 02/07/2023]
Abstract
Embryo-environment interactions affecting cardio-respiratory development in vertebrates have been extensively studied, but an equally extensive conceptual framework for interpreting and interrelating these developmental events has lagged behind. In this review, we consider the conceptual constructs of "developmental plasticity", "critical windows", "developmental trajectory" and related concepts as they apply to both vertebrate and invertebrate development. Developmental plasticity and the related phenomenon of "heterokairy" are considered as a subset of phenotypic plasticity, and examples of cardiovascular, respiratory and metabolic plasticity illustrate the variable outcomes of embryo-environment interactions. The concept of the critical window is revealed to be overarching in cardio-respiratory development, and events originating within a critical window, potentially mitigated by "self-repair" capabilities of the embryo, are shown to result in modified developmental trajectories and, ultimately, modified adult phenotype. Finally, epigenetics, fetal programming and related phenomena are considered in the context of potentially life-long cardio-respiratory phenotypic modification resulting from embryo-environment interactions.
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Affiliation(s)
- Warren W Burggren
- Developmental Integrative Biology Cluster, Department of Biological Sciences, University of North Texas, Denton, TX 76203-5017, USA.
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47
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Warkentin KM. Environmentally Cued Hatching across Taxa: Embryos Respond to Risk and Opportunity. Integr Comp Biol 2011; 51:14-25. [DOI: 10.1093/icb/icr017] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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48
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Augustine S, Gagnaire B, Floriani M, Adam-Guillermin C, Kooijman SALM. Developmental energetics of zebrafish, Danio rerio. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:275-83. [PMID: 21440658 DOI: 10.1016/j.cbpa.2011.03.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 10/18/2022]
Abstract
Using zebrafish (Danio rerio) as a case study, we show that the maturity concept of Dynamic Energy Budget (DEB) theory is a useful metric for developmental state. Maturity does not depend on food or temperature contrary to age and to some extent length. We compile the maturity levels for each developmental milestone recorded in staging atlases. The analysis of feeding, growth, reproduction and aging patterns throughout the embryo, juvenile and adult life stages are well-captured by a simple extension of the standard DEB model and reveals that embryo development is slow relative to adults. A threefold acceleration of development occurs during the larval period. Moreover we demonstrate that growth and reproduction depend on food in predictable ways and their simultaneous observation is necessary to estimate parameters. We used data on diverse aspects of the energy budget simultaneously for parameter estimation using the covariation method. The lowest mean food intake level to initiate reproduction was found to be as high as 0.6 times the maximum level. The digestion efficiency for Tetramin™ was around 0.5, growth efficiency was just 0.7 and the value for the allocation fraction to soma (0.44) was close to the one that maximizes ultimate reproduction.
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Affiliation(s)
- S Augustine
- Laboratory of Radioecology and Ecotoxicology, DEI/SECRE/LRE, Institute of Radioprotection and Nuclear Safety (IRSN), Caradache, Building 186, BP3, 13115 St-Paul-lez-Durance Cedex, France.
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Podrabsky JE, Garrett IDF, Kohl ZF. Alternative developmental pathways associated with diapause regulated by temperature and maternal influences in embryos of the annual killifish Austrofundulus limnaeus. J Exp Biol 2010; 213:3280-8. [PMID: 20833920 PMCID: PMC2936969 DOI: 10.1242/jeb.045906] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2010] [Indexed: 11/20/2022]
Abstract
Embryos of the annual killifish Austrofundulus limnaeus enter a state of developmental arrest termed diapause as part of their normal developmental program. Diapause can occur at two distinct developmental stages in this species, termed diapause II and III. When incubated at 25°C, most embryos enter diapause II, whereas a small percentage of 'escape' embryos develop continuously past diapause II and enter diapause III. Control of entry into diapause II can be altered by maternal influences and the incubation environment experienced by the embryos. Young females produce a higher proportion of escape embryos than do older females. In addition, increasing the incubation temperature from 25 to 30°C induces all embryos to escape from diapause. Surprisingly, escape embryos follow a different morphological and physiological developmental trajectory than do embryos that enter diapause II. Development of anterior structures is advanced compared with that of posterior structures in escape embryos when compared with embryos that will enter diapause II. The difference in timing of development for these two trajectories is consistent with changes observed between two species but is very atypical of variation observed within a species. Importantly, the two developmental pathways diverge early in development, during the segmentation period, when, according to evolutionary theory, constraint on developmental pathways should be relatively high. The possession of alternative developmental pathways in a vertebrate embryo is a novel finding, the ecological and evolutionary importance of which is still unknown, but potentially significant in terms of life-history evolution.
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Affiliation(s)
- Jason E Podrabsky
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97207-0751, USA.
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Liao J, Wang Y, Zhao L, Liu N. Effects of environmental factors on organ mass of midday gerbil (Meriones meridianus Pallas, 1773). Mamm Biol 2010. [DOI: 10.1016/j.mambio.2009.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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