1
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De Padova J, Anderson NK, Halbauer R, Preininger D, Fuxjager MJ. Acute hypoxia exposure rapidly triggers behavioral changes linked to cutaneous gas exchange in Lake Titicaca frogs. Behav Processes 2024; 219:105047. [PMID: 38762053 DOI: 10.1016/j.beproc.2024.105047] [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: 12/07/2023] [Revised: 03/07/2024] [Accepted: 05/14/2024] [Indexed: 05/20/2024]
Abstract
Ventilation is critical to animal life-it ensures that individuals move air/water across their respiratory surface, and thus it sustains gas exchange with the environment. Many species have evolved highly specialized (if not unusual) ventilatory mechanisms, including the use of behavior to facilitate different aspects of breathing. However, these behavioral traits are often only described anecdotally, and the ecological conditions that elicit them are typically unclear. We study one such "ventilation behavior" in Lake Titicaca frogs (Telmatobius culeus). These frogs inhabit high-altitude (i.e., low oxygen) lakes in the Andean Mountains of South America, and they have become textbook examples of cutaneous gas exchange, which is essentially breathing that occurs across the skin. Accordingly, this species has evolved large, baggy skin-folds that dangle from the body to increase the surface area for ventilation. We show that individuals exposed to acute hypoxic conditions that mirror what free-living individuals likely encounter quickly (within minutes) decrease their activity levels, and thus become very still. If oxygen levels continue to decline, the frogs soon begin to perform push-up behaviors that presumably break the low-oxygen boundary layer around skin-folds to increase the conductance of the water/skin gas exchange pathway. Altogether, we suspect that individuals rapidly adjust aspects of their behavior in response to seemingly sudden changes to the oxygen environment as a mechanism to fine tune cutaneous respiration.
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Affiliation(s)
- Jordan De Padova
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
| | - Nigel K Anderson
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
| | | | - Doris Preininger
- Vienna Zoo, Vienna, Austria; Department of Evolutionary Biology, University of Vienna, Austria
| | - Matthew J Fuxjager
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA.
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2
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Johnson JR, Griffitt RJ. Environmentally relevant concentrations of aqueous atorvastatin produce alterations in cholesterol biosynthesis and gene expression patterns in Xenopus laevis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 269:106856. [PMID: 38401338 DOI: 10.1016/j.aquatox.2024.106856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/26/2024]
Abstract
Numerous studies report active pharmaceutical compounds detected in both wastewater effluent and surface waters. Exposure to statin drugs in general, and atorvastatin in particular, is likely to be a concern. We hypothesized that chronic exposure to low concentrations of atorvastatin in water would result in an adverse effect on production of steroids regulating growth and development of the model amphibian Xenopus laevis. The FETAX assay was used to evaluate the effects of a range of doses of atorvastatin on developing embryos. A 60 day metamorphosis assay assessed the effects of aqueous atorvastatin exposure at environmentally concentrations on metamorphosing tadpoles. A 60 day chronic flow-through exposure evaluated the effects of chronic low concentrations of atorvastatin on adults. The purpose of the FETAX assay was to confirm that atorvastatin can reduce circulating cholesterol in X. laevis with a similar manner to that expected in humans. The results of the 60-day flow-through exposure on metamorphosing tadpoles showed significant evidence of altered cholesterol biosynthesis. The dose-dependent increase in cyp19a1 expression also indicated that the steroidogenesis pathway was affected. The RNAseq analysis confirmed that exposure to environmentally relevant concentrations of atorvastatin does cause significant alterations to global transcriptional profiles in a manner consistent with dysregulation of the cholesterol biosynthesis pathway, both through the downregulation of many genes involved in that pathway, but also in the impacts to other, related pathways. The qPCR data for both adult males and adult females indicated only slight changes in expression with the exception that hmgcr was significantly downregulated in males, and cyp3a4 expression was significantly downregulated in females. The data we present here indicated that chronic exposure to environmentally relevant concentrations of atorvastatin does have the potential to impact early life stage frogs, particularly by altering expression of genes involved in critical molecular pathways.
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Affiliation(s)
- J R Johnson
- Department of Coastal Sciences, University of Southern Mississippi, Hattiesburg, MS 39407, USA
| | - R J Griffitt
- Department of Coastal Sciences, University of Southern Mississippi, Hattiesburg, MS 39407, USA.
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3
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Ludington AJ, Hammond JM, Breen J, Deveson IW, Sanders KL. New chromosome-scale genomes provide insights into marine adaptations of sea snakes (Hydrophis: Elapidae). BMC Biol 2023; 21:284. [PMID: 38066641 PMCID: PMC10709897 DOI: 10.1186/s12915-023-01772-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Sea snakes underwent a complete transition from land to sea within the last ~ 15 million years, yet they remain a conspicuous gap in molecular studies of marine adaptation in vertebrates. RESULTS Here, we generate four new annotated sea snake genomes, three of these at chromosome-scale (Hydrophis major, H. ornatus and H. curtus), and perform detailed comparative genomic analyses of sea snakes and their closest terrestrial relatives. Phylogenomic analyses highlight the possibility of near-simultaneous speciation at the root of Hydrophis, and synteny maps show intra-chromosomal variations that will be important targets for future adaptation and speciation genomic studies of this system. We then used a strict screen for positive selection in sea snakes (against a background of seven terrestrial snake genomes) to identify genes over-represented in hypoxia adaptation, sensory perception, immune response and morphological development. CONCLUSIONS We provide the best reference genomes currently available for the prolific and medically important elapid snake radiation. Our analyses highlight the phylogenetic complexity and conserved genome structure within Hydrophis. Positively selected marine-associated genes provide promising candidates for future, functional studies linking genetic signatures to the marine phenotypes of sea snakes and other vertebrates.
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Affiliation(s)
- Alastair J Ludington
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
| | - Jillian M Hammond
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Darlinghurst, Australia
| | - James Breen
- Indigenous Genomics, Telethon Kids Institute, Adelaide, Australia
- John Curtin School of Medical Research, College of Health & Medicine, Australian National University, Canberra, Australia
| | - Ira W Deveson
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- Centre for Population Genomics, Garvan Institute of Medical Research and Murdoch Children's Research Institute, Darlinghurst, Australia
- Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Kate L Sanders
- School of Biological Sciences, The University of Adelaide, Adelaide, SA, 5005, Australia.
- The South Australian Museum, Adelaide, Australia.
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4
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Xu S, Dai Q, Zheng Y. Male spiny frogs enter the underwater battlefield with loose skin exhibiting enhanced penetration of capillaries into the epidermis. ZOOLOGICAL LETTERS 2023; 9:19. [PMID: 37803369 PMCID: PMC10557191 DOI: 10.1186/s40851-023-00219-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 08/23/2023] [Indexed: 10/08/2023]
Abstract
The skin has multiple functions, and capillaries can penetrate the epidermis to shorten the diffusion path while allowing maintenance of overall epidermal thickness for nonrespiratory roles. However, a method for quantifying the capillary penetration extent is lacking. Such a method may facilitate making comparisons and detecting associations, potentially making the extent a useful variable in biological studies. We quantified the extent as the ratio of the average minimum thickness of epidermis overlying each capillary to the average epidermal thickness along a skin section and then explored its performance in the Emei mustache toad, Leptobrachium boringii, a species in which breeding males with loose skin call and fight each other with maxillary spines underwater. The ratio showed informative associations with other variables, such as perfused capillary density. It displayed small intragroup variation and could be more sensitive than other variables in revealing structural differences in the skin. The ratio estimates were lowest and were correlated with epidermal and stratum compactum thicknesses in breeding males, i.e., a covariation but not reinforcement against stabbing, constituting early evidence consistent with the increased extensibility of loose skin conferring a defensive advantage during combat in amphibians. In addition, our results lead to the hypothesis that high hemoglobin density along subepidermal capillaries favors the maintenance of low blood partial oxygen pressure and hence increases cutaneous oxygen uptake. We also provide evidence supporting the new idea that the cooccurrence of loose skin and underwater calling found in some frogs can be explained by the latter benefiting from a large functional respiratory surface area. Awareness of the usefulness of the ratio may promote its application and the quantification of the penetration. Regarding exchange surface design, these findings for L. boringii imply a case in which looseness increases surface area as well as prevents damage.
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Affiliation(s)
- Shuang Xu
- Chengdu Institute of Biology, Chinese Academy of Sciences, #9 of Section 4, Ren-Min-Nan Road, Wuhou District, Chengdu, 610041, Sichuan Province, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qiang Dai
- Chengdu Institute of Biology, Chinese Academy of Sciences, #9 of Section 4, Ren-Min-Nan Road, Wuhou District, Chengdu, 610041, Sichuan Province, China
| | - Yuchi Zheng
- Chengdu Institute of Biology, Chinese Academy of Sciences, #9 of Section 4, Ren-Min-Nan Road, Wuhou District, Chengdu, 610041, Sichuan Province, China.
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, Sichuan, China.
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5
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Burnley M. Invited review: The speed-duration relationship across the animal kingdom. Comp Biochem Physiol A Mol Integr Physiol 2023; 279:111387. [PMID: 36740171 DOI: 10.1016/j.cbpa.2023.111387] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
The parameters of the hyperbolic speed-duration relationship (the asymptote critical speed, CS, and the curvature constant, D') provide estimates of the maximal steady state speed (CS) and the distance an animal can run, swim, or fly at speeds above CS before it is forced to slow down or stop (D'). The speed-duration relationship has been directly studied in humans, horses, mice and rats. The technical difficulties with treadmill running in dogs and the relatively short greyhound race durations means that, perhaps surprisingly, it has not been assessed in dogs. The endurance capabilities of lizards, crabs and salamanders has also been measured, and the speed-duration relationship can be calculated from these data. These analyses show that 1) raising environmental temperature from 25 °C to 40 °C in lizards can double the CS with no change in D'; 2) that lungless salamanders have an extremely low critical speed due, most likely, to O2 diffusion limitations associated with cutaneous respiration; and 3) the painted ghost crab possesses the highest endurance parameter ratio (D'/CS) yet recorded (470 s), allowing it to maintain high speeds for extended periods. Although the speed-duration relationship has not been measured in fish, the sustainable swimming speed has been quantified in a range of species and is conceptually similar to the maximal steady state in humans. The high aerobic power of birds and low metabolic cost of transport during flight permits the extreme feats of endurance observed in bird migrations. However, the parameters of the avian speed-duration relationship have not been quantified.
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Affiliation(s)
- Mark Burnley
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, UK.
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6
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Forlenza AE, Galbraith HS, Blakeslee CJ, Glazier DS. Ontogenetic changes in body shape and the scaling of metabolic rate in the American eel (Anguilla rostrata). Physiol Biochem Zool 2022; 95:430-437. [DOI: 10.1086/721189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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7
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Zheng Y, Xie F. Underwater calling behavior in two high‐altitude frog species. J Zool (1987) 2022. [DOI: 10.1111/jzo.12960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Y. Zheng
- Chengdu Institute of Biology Chinese Academy of Sciences Chengdu China
| | - F. Xie
- Chengdu Institute of Biology Chinese Academy of Sciences Chengdu China
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8
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Akat E, Yenmiş M, Pombal MA, Molist P, Megías M, Arman S, Veselỳ M, Anderson R, Ayaz D. Comparison of Vertebrate Skin Structure at Class Level: A Review. Anat Rec (Hoboken) 2022; 305:3543-3608. [DOI: 10.1002/ar.24908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Esra Akat
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
| | - Melodi Yenmiş
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
| | - Manuel A. Pombal
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Pilar Molist
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Manuel Megías
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Sezgi Arman
- Sakarya University, Faculty of Science and Letters, Biology Department Sakarya Turkey
| | - Milan Veselỳ
- Palacky University, Faculty of Science, Department of Zoology Olomouc Czechia
| | - Rodolfo Anderson
- Departamento de Zoologia, Instituto de Biociências Universidade Estadual Paulista São Paulo Brazil
| | - Dinçer Ayaz
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
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9
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Prescott LA, Regish AM, McMahon SJ, McCormick SD, Rummer JL. Rapid embryonic development supports the early onset of gill functions in two coral reef damselfishes. J Exp Biol 2021; 224:272637. [PMID: 34708857 DOI: 10.1242/jeb.242364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 10/25/2021] [Indexed: 11/20/2022]
Abstract
The gill is one of the most important organs for growth and survival of fishes. Early life stages in coral reef fishes often exhibit extreme physiological and demographic characteristics that are linked to well-established respiratory and ionoregulatory processes. However, gill development and function in coral reef fishes is not well understood. Therefore, we investigated gill morphology, oxygen uptake and ionoregulatory systems throughout embryogenesis in two coral reef damselfishes, Acanthochromis polyacanthus and Amphiprion melanopus (Pomacentridae). In both species, we found key gill structures to develop rapidly early in the embryonic phase. Ionoregulatory cells appear on gill filaments 3-4 days post-fertilization and increase in density, whilst disappearing or shrinking in cutaneous locations. Primary respiratory tissue (lamellae) appears 5-7 days post-fertilization, coinciding with a peak in oxygen uptake rates of the developing embryos. Oxygen uptake was unaffected by phenylhydrazine across all ages (pre-hatching), indicating that haemoglobin is not yet required for oxygen uptake. This suggests that gills have limited contribution to respiratory functions during embryonic development, at least until hatching. Rapid gill development in damselfishes, when compared with that in most previously investigated fishes, may reflect preparations for a high-performance, challenging lifestyle on tropical reefs, but may also make reef fishes more vulnerable to anthropogenic stressors.
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Affiliation(s)
- Leteisha A Prescott
- ARC Centre of Excellence for Coral Reef Studies, Townsville, QLD 4811, Australia.,College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| | - Amy M Regish
- US Geological Survey, Eastern Ecological Science Center, Conte Anadromous Fish Research Laboratory, Turners Falls, MA 01376, USA
| | - Shannon J McMahon
- ARC Centre of Excellence for Coral Reef Studies, Townsville, QLD 4811, Australia
| | - Stephen D McCormick
- US Geological Survey, Eastern Ecological Science Center, Conte Anadromous Fish Research Laboratory, Turners Falls, MA 01376, USA.,Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Jodie L Rummer
- ARC Centre of Excellence for Coral Reef Studies, Townsville, QLD 4811, Australia.,College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
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10
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Marina G, Glover CN, Goss GG, Zimmer AM. The skin of adult rainbow trout is not a significant site of ammonia clearance from the blood. JOURNAL OF FISH BIOLOGY 2021; 99:1529-1534. [PMID: 34159596 DOI: 10.1111/jfb.14831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
We hypothesized that the skin acts as an extrabranchial route for ammonia excretion in adult rainbow trout (Oncorhynchus mykiss) following high environmental ammonia (HEA) exposure. Trunks of control or HEA-exposed trout were perfused with saline containing 0 or 1 mmol l-1 NH4 + . Cutaneous ammonia excretion rates increased 2.5-fold following HEA exposure, however there was no difference in rates between trunks perfused with 0 or 1 mmol l-1 NH4 + . The skin is therefore capable of excreting its own ammonia load, but it does not clear circulating ammonia from the plasma.
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Affiliation(s)
- Giacomin Marina
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
| | - Chris N Glover
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Science and Technology and Athabasca River Basin Research Institute, Athabasca University, Athabasca, Alberta, Canada
| | - Greg G Goss
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
| | - Alex M Zimmer
- Department of Biological Sciences, CW 405, Biological Sciences Bldg, University of Alberta, Edmonton, Alberta, Canada
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11
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Johnson BB, Searle JB, Sparks JP. Novel Allometric Estimators Improve Estimation Accuracy of Body Surface Area, Volume, and Surface Area-to-Volume Ratio in Lungless Salamanders (Urodela: Plethodontidae). HERPETOLOGICA 2021. [DOI: 10.1655/herpetologica-d-21-00013.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Benjamin B. Johnson
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy B. Searle
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jed P. Sparks
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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12
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McArley TJ, Morgenroth D, Zena LA, Ekström AT, Sandblom E. Normoxic limitation of maximal oxygen consumption rate, aerobic scope and cardiac performance in exhaustively exercised rainbow trout (Oncorhynchus mykiss). J Exp Biol 2021; 224:271087. [PMID: 34323276 DOI: 10.1242/jeb.242614] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/25/2021] [Indexed: 01/22/2023]
Abstract
In fish, maximum O2 consumption rate (ṀO2,max) and aerobic scope can be expanded following exhaustive exercise in hyperoxia; however, the mechanisms explaining this are yet to be identified. Here, in exhaustively exercised rainbow trout (Oncorhynchus mykiss), we assessed the influence of hyperoxia on ṀO2,max, aerobic scope, cardiac function and blood parameters to address this knowledge gap. Relative to normoxia, ṀO2,max was 33% higher under hyperoxia, and this drove a similar increase in aerobic scope. Cardiac output was significantly elevated under hyperoxia at ṀO2,max because of increased stroke volume, indicating that hyperoxia released a constraint on cardiac contractility apparent with normoxia. Thus, hyperoxia improved maximal cardiac performance, thereby enhancing tissue O2 delivery and allowing a higher ṀO2,max. Venous blood O2 partial pressure (PvO2) was elevated in hyperoxia at ṀO2,max, suggesting a contribution of improved luminal O2 supply in enhanced cardiac contractility. Additionally, despite reduced haemoglobin and higher PvO2, hyperoxia treated fish retained a higher arterio-venous O2 content difference at ṀO2,max. This may have been possible because of hyperoxia offsetting declines in arterial oxygenation that are known to occur following exhaustive exercise in normoxia. If this occurs, increased contractility at ṀO2,max with hyperoxia may also relate to an improved O2 supply to the compact myocardium via the coronary artery. Our findings show ṀO2,max and aerobic scope may be limited in normoxia following exhaustive exercise as a result of constrained maximal cardiac performance and highlight the need to further examine whether or not exhaustive exercise protocols are suitable for eliciting ṀO2,max and estimating aerobic scope in rainbow trout.
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Affiliation(s)
- Tristan J McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Lucas A Zena
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Andreas T Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
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13
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Kurita M, Noma S, Ishimatsu A. Morphology of the respiratory vasculature of the mudskipper Boleophthalmus pectinirostris (Gobiidae: Oxudercinae). J Morphol 2021; 282:1557-1568. [PMID: 34323310 DOI: 10.1002/jmor.21404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/23/2021] [Accepted: 07/24/2021] [Indexed: 11/12/2022]
Abstract
The gross morphology of the circulatory system in the amphibious mudskipper, Boleophthalmus pectinirostris, conforms with the typical teleost configuration, in which gills and systemic vascular beds are connected in series. However, at the microscopic level, the vasculatures of the respiratory organs, the inner epithelium of the bucco-opercular cavity, gills and skin, all show specializations for aerial gas exchange. The epithelium of the bucco-opercular cavity is heavily vascularized by respiratory capillaries that are derived from systemic arteries of the head, mainly branches of the hyomandibular artery and the dorsal opercular artery. The respiratory circuit of the secondary lamellae of the gills consists of 15-17 channels running in parallel, unlike the lacuna-like blood space of aquatic fishes. The most notable specialization is found in the microcirculation of the respiratory papillae in the skin. Each respiratory papilla is supplied by an arteriole that is derived from a systemic artery, mainly the cranial artery in the head and the segmental artery in the trunk. The arteriole divides several times along its course to the apical region of a papilla, where the branches split into approximately 65 capillaries that radiate to the periphery of the papilla. The capillaries twist 5-10 times before they unite to form the venules that encircle maximally half the circumference of a papilla. A variable number of venules merge into a vein, which progressively coalesces with veins from other papillae. There is no morphological specialization that separates oxygen-rich effluent blood of the epithelia of the bucco-opercular cavity and the respiratory papillae of the skin from the oxygen-poor systemic venous blood. The ecophysiological implications of these findings are discussed in relation to the environmental conditions that B. pectinirostris experience during tidal cycles in the warm months and during overwintering.
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Affiliation(s)
- Mariko Kurita
- Faculty of Fisheries, Nagasaki University, Nagasaki, Japan
| | - Shohei Noma
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Atsushi Ishimatsu
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan.,Institute for East China Sea Research, Organization of Marine Science and Technology, Nagasaki University, Nagasaki, Japan
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14
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Johnson BB, Searle JB, Sparks JP. Genome size influences adaptive plasticity of water loss, but not metabolic rates, in lungless salamanders. J Exp Biol 2021; 224:237790. [PMID: 33914029 DOI: 10.1242/jeb.242196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/09/2021] [Indexed: 12/14/2022]
Abstract
Many expressions of phenotype, such as physiological performance, integrate multiple underlying traits to function. Linking component traits to adaptive physiology thus gives insight into mechanisms of selection acting on performance. Genome size (C-value) is a trait that influences physiology in multiple taxa by exerting a nucleotypic effect, constraining cell size and cellular physiology such that whole-organism mass-specific metabolism is reduced with increasing C-value. We tested for this mechanism of C-value function acting in lungless salamanders, plus an unexplored potential mechanism of C-value effects constraining water transport across the body surface to influence cutaneous water loss rates. We found no evidence for a nucleotypic effect on metabolic rates, but we demonstrate a relationship between C-value and water loss physiology. Under warmer experimental conditions, C-value was inversely correlated with water loss and positively correlated with resistance to water loss, which demonstrated adaptive plasticity at higher temperatures. We hypothesize that this pattern results from differences in cell size constraining diffusion and evaporation of water from the skin under warm conditions when cutaneous perfusion is reduced. Testing this hypothesis may confirm a previously unappreciated adaptive role for C-value variation in this group, and reveals the possibility that genome size influences physiological exchange across transport barriers more broadly.
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Affiliation(s)
- Benjamin B Johnson
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY14853, USA
| | - Jeremy B Searle
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY14853, USA
| | - Jed P Sparks
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY14853, USA
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15
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Rodgers EM, Franklin CE, Noble DWA. Diving in hot water: a meta-analytic review of how diving vertebrate ectotherms will fare in a warmer world. J Exp Biol 2021; 224:224/Suppl_1/jeb228213. [PMID: 33627460 DOI: 10.1242/jeb.228213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Diving ectothermic vertebrates are an important component of many aquatic ecosystems, but the threat of climate warming is particularly salient to this group. Dive durations typically decrease as water temperatures rise; yet, we lack an understanding of whether this trend is apparent in all diving ectotherms and how this group will fare under climate warming. We compiled data from 27 studies on 20 ectothermic vertebrate species to quantify the effect of temperature on dive durations. Using meta-analytic approaches, we show that, on average, dive durations decreased by 11% with every 1°C increase in water temperature. Larger increases in temperature (e.g. +3°C versus +8-9°C) exerted stronger effects on dive durations. Although species that respire bimodally are projected to be more resilient to the effects of temperature on dive durations than purely aerial breathers, we found no significant difference between these groups. Body mass had a weak impact on mean dive durations, with smaller divers being impacted by temperature more strongly. Few studies have examined thermal phenotypic plasticity (N=4) in diving ectotherms, and all report limited plasticity. Average water temperatures in marine and freshwater habitats are projected to increase between 1.5 and 4°C in the next century, and our data suggest that this magnitude of warming could translate to substantial decreases in dive durations, by approximately 16-44%. Together, these data shed light on an overlooked threat to diving ectothermic vertebrates and suggest that time available for underwater activities, such as predator avoidance and foraging, may be shortened under future warming.
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Affiliation(s)
- Essie M Rodgers
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, St Lucia, 4072 Queensland, Australia
| | - Daniel W A Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
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16
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Ferner K. Development of the skin in the eastern quoll (Dasyurus viverrinus) with focus on cutaneous gas exchange in the early postnatal period. J Anat 2020; 238:426-445. [PMID: 32974934 PMCID: PMC7812133 DOI: 10.1111/joa.13316] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/11/2020] [Accepted: 09/02/2020] [Indexed: 12/01/2022] Open
Abstract
A morphological and morphometric study of the skin development in the eastern quoll (Dasyurus viverrinus) was conducted to follow the transition from cutaneous to pulmonary gas exchange in this extremely immature marsupial species. Additionally, the development of the cardiac and respiratory system was followed, to evaluate the systemic prerequisites allowing for cutaneous respiration. The skin in the newborn D. viverrinus was very thin (36 ± 3 µm) and undifferentiated (no hair follicles, no sebaceous and perspiratory glands). Numerous superficial cutaneous capillaries were encountered, closely associated with the epidermis, allowing for gaseous exchange. The capillary volume density was highest in the neonate (0.33 ± 0.04) and decreased markedly during the first 4 days (0.06 ± 0.01). In the same time period, the skin diffusion barrier increased from 9 ± 1 µm to 44 ± 6 µm. From this age on the skin development was characterized by thickening of the different cutaneous layers, formation of hair follicles (day 55) and the occurrence of subcutaneous fat (day 19). The heart of the neonate D. viverrinus had incomplete interatrial, inter‐ventricular, and aortico‐pulmonary septa, allowing for the possibility that oxygenated blood from the skin mixes with that of the systemic circulation. The fast‐structural changes in the systemic circulations (closing all shunts) in the early postnatal period (3 days) necessitate the transition from cutaneous to pulmonary respiration despite the immaturity of the lungs. At this time, the lung was still at the canalicular stage of lung development, but had to be mature enough to meet the respiratory needs of the growing organism. The morphometric results for the skin development of D. viverrinus suggest that cutaneous respiration is most pronounced in neonates and decreases rapidly during the first 3 days of postnatal life. After this time a functional transition of the skin from cutaneous respiration to insulation and protection of the body takes place.
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Affiliation(s)
- Kirsten Ferner
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
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17
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Clarac F, Scheyer TM, Desojo JB, Cerda IA, Sanchez S. The evolution of dermal shield vascularization in Testudinata and Pseudosuchia: phylogenetic constraints versus ecophysiological adaptations. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190132. [PMID: 31928197 PMCID: PMC7017437 DOI: 10.1098/rstb.2019.0132] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2019] [Indexed: 01/18/2023] Open
Abstract
Studies on living turtles have demonstrated that shells are involved in the resistance to hypoxia during apnea via bone acidosis buffering; a process which is complemented with cutaneous respiration, transpharyngeal and cloacal gas exchanges in the soft-shell turtles. Bone acidosis buffering during apnea has also been identified in crocodylian osteoderms, which are also known to employ heat transfer when basking. Although diverse, many of these functions rely on one common trait: the vascularization of the dermal shield. Here, we test whether the above ecophysiological functions played an adaptive role in the evolutionary transitions between land and aquatic environments in both Pseudosuchia and Testudinata. To do so, we measured the bone porosity as a proxy for vascular density in a set of dermal plates before performing phylogenetic comparative analyses. For both lineages, the dermal plate porosity obviously varies depending on the animal lifestyle, but these variations prove to be highly driven by phylogenetic relationships. We argue that the complexity of multi-functional roles of the post-cranial dermal skeleton in both Pseudosuchia and Testudinata probably is the reason for a lack of obvious physiological signal, and we discuss the role of the dermal shield vascularization in the evolution of these groups. This article is part of the theme issue 'Vertebrate palaeophysiology'.
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Affiliation(s)
- François Clarac
- Department of Organismal Biology, Subdepartment of Evolution and Development, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
| | - Torsten M. Scheyer
- Paleontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Julia B. Desojo
- CONICET, División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n°, B1900FWA La Plata, Argentina
| | - Ignacio A. Cerda
- CONICET, Argentina y Instituto de Investigacion en Paleobiología y Geología, Universidad Nacional de Río Negro, Museo Carlos Ameghino, Belgrano 1700, Paraje Pichi Ruca (predio Marabunta), 8300 Cipolletti, Río Negro, Argentina
| | - Sophie Sanchez
- Department of Organismal Biology, Subdepartment of Evolution and Development, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS-40220, 38043 Grenoble Cedex, France
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18
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Burggren W, Filogonio R, Wang T. Cardiovascular shunting in vertebrates: a practical integration of competing hypotheses. Biol Rev Camb Philos Soc 2019; 95:449-471. [PMID: 31859458 DOI: 10.1111/brv.12572] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 10/30/2019] [Accepted: 11/07/2019] [Indexed: 12/20/2022]
Abstract
This review explores the long-standing question: 'Why do cardiovascular shunts occur?' An historical perspective is provided on previous research into cardiac shunts in vertebrates that continues to shape current views. Cardiac shunts and when they occur is then described for vertebrates. Nearly 20 different functional reasons have been proposed as specific causes of shunts, ranging from energy conservation to improved gas exchange, and including a plethora of functions related to thermoregulation, digestion and haemodynamics. It has even been suggested that shunts are merely an evolutionary or developmental relic. Having considered the various hypotheses involving cardiovascular shunting in vertebrates, this review then takes a non-traditional approach. Rather than attempting to identify the single 'correct' reason for the occurrence of shunts, we advance a more holistic, integrative approach that embraces multiple, non-exclusive suites of proposed causes for shunts, and indicates how these varied functions might at least co-exist, if not actually support each other as shunts serve multiple, concurrent physiological functions. It is argued that deposing the 'monolithic' view of shunting leads to a more nuanced view of vertebrate cardiovascular systems. This review concludes by suggesting new paradigms for testing the function(s) of shunts, including experimentally placing organ systems into conflict in terms of their perfusion needs, reducing sources of variation in physiological experiments, measuring possible compensatory responses to shunt ablation, moving experiments from the laboratory to the field, and using cladistics-related approaches in the choice of experimental animals.
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Affiliation(s)
- Warren Burggren
- Department of Biological Sciences, Developmental Integrative Biology Cluster, University of North Texas, Denton, TX, 76203-5220, U.S.A
| | - Renato Filogonio
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus C, 8000, Denmark.,Aarhus Institute of Advanced Sciences (AIAS), Aarhus University, Aarhus C, 8000, Denmark
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19
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Zimmer AM, Mandic M, Rourke KM, Perry SF. Breathing with fins: do the pectoral fins of larval fishes play a respiratory role? Am J Physiol Regul Integr Comp Physiol 2019; 318:R89-R97. [PMID: 31692366 DOI: 10.1152/ajpregu.00265.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Convective water flow across respiratory epithelia in water-breathing organisms maintains transcutaneous oxygen (O2) partial pressure (Po2) gradients that drive O2 uptake. Following hatch, larval fishes lack a developed gill and the skin is the dominant site of gas transfer, yet few studies have addressed the contribution of convective water flow to cutaneous O2 uptake in larvae. We hypothesized that the pectoral fins, which can generate water flow across the skin in larvae, promote transcutaneous O2 transfer and thus aid in O2 uptake. In zebrafish (Danio rerio), the frequency of pectoral fin movements increased in response to hypoxia at 4 days postfertilization (dpf), but the response was blunted by 15 dpf, when the gills become the dominant site of O2 uptake, and was absent by 21 dpf. In rainbow trout (Oncorhynchus mykiss), Po2 measured at the skin surface of ventilating larvae was lower when the pectoral fins had been surgically removed, directly demonstrating that fins contribute to convective flow that dissipates cutaneous Po2 boundary layers. Lack of pectoral fins compromised whole animal O2 consumption in trout during hypoxia, but this effect was absent in zebrafish. Overall, our findings support a respiratory role of the pectoral fins in rainbow trout, but their involvement in zebrafish remains equivocal.
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Affiliation(s)
- Alex M Zimmer
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Milica Mandic
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Kaitlyn M Rourke
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Steve F Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
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20
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Zheng Y. The co‐occurrence of loose skin and underwater calling in frogs—further evidence from
Amolops ricketti
and its implications. J Zool (1987) 2019. [DOI: 10.1111/jzo.12722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Y. Zheng
- Department of Herpetology Chengdu Institute of Biology Chinese Academy of Sciences Chengdu China
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21
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Aerobic Pushups: Cutaneous Ventilation in Overwintering Smooth Softshell Turtles, Apalone mutica. J HERPETOL 2019. [DOI: 10.1670/18-038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Blanchard TS, Whitehead A, Dong YW, Wright PA. Phenotypic flexibility in respiratory traits is associated with improved aerial respiration in an amphibious fish out of water. ACTA ACUST UNITED AC 2019; 222:jeb.186486. [PMID: 30446543 DOI: 10.1242/jeb.186486] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/14/2018] [Indexed: 01/17/2023]
Abstract
Amphibious fishes have evolved multiple adaptive strategies for respiring out of water, but there has been less focus on reversible plasticity. We tested the hypothesis that when amphibious fishes leave water, enhanced respiratory performance on land is the result of rapid functional phenotypic flexibility of respiratory traits. We acclimated four isogenic strains of Kryptolebias marmoratus to air for 0, 1, 3 or 7 days. We compared respiratory performance out of water with traits linked to the O2 cascade. Aerial O2 consumption rate was measured over a step-wise decrease in O2 levels. There were significant differences between strains, but time out of water had the largest impact on measured parameters. K ryptolebias marmoratus had improved respiratory performance [lower aerial critical oxygen tension (P crit), higher regulation index (RI)] after only 1 day of air exposure, and these changes were strongly associated with the change in hematocrit and dorsal cutaneous angiogenesis. Additionally, we found that 1 h of air exposure induced the expression of four angiogenesis-associated genes - vegfa, angpt2, pecam-1 and efna1 - in the skin. After 7 days in air, respiratory traits were not significantly linked to the variation in either aerial P crit or RI. Overall, our data indicate that there are two phases involved in the enhancement of aerial respiration: an initial rapid response (1 day) and a delayed response (7 days). We found evidence for the hypothesis that respiratory performance on land in amphibious fishes is the result of rapid flexibility in both O2 uptake and O2 carrying capacity.
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Affiliation(s)
- Tessa S Blanchard
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California Davis, Davis, CA 95616, USA
| | - Yunwei W Dong
- Department of Environmental Toxicology, University of California Davis, Davis, CA 95616, USA.,State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen 361102, People's Republic of China
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
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23
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Noradrenergic modulation determines respiratory network activity during temperature changes in the in vitro brainstem of bullfrogs. Respir Physiol Neurobiol 2018; 258:25-31. [DOI: 10.1016/j.resp.2018.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/20/2018] [Accepted: 10/03/2018] [Indexed: 01/22/2023]
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24
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Galindo C, Cruz E, Bernal M. Evaluation of the combined temperature and relative humidity preferences of the Colombian terrestrial salamander Bolitoglossa ramosi (Amphibia: Plethodontidae). CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0330] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Temperature and humidity are critical factors for terrestrial lungless salamanders, as their body temperatures are largely determined by the environmental temperature and require moisture to sustain cutaneous respiration. Herein, we evaluated the preference of Bolitoglossa ramosi Brame and Wake, 1972 between a high temperature and a high relative humidity (RH), the influence of temperature on RH preferences, and the influence of RH on the thermal preferences. This study was performed in a field location in the municipality of Líbano, Tolima, Colombia. There, on different nights, we collected 84 adult B. ramosi and carried out the preference experiments, using aluminum troughs with different thermal and RH gradients. We found that between high temperature and high RH, B. ramosi preferred high RH. However, B. ramosi selected high temperatures when the gradient had a high RH and low temperatures when the gradient had a low RH. These results show that B. ramosi is able to thermoregulate and hydroregulate. Nevertheless, hydroregulation seems to be more important than thermoregulation because B. ramosi always selected the high RH gradients, while their thermal selection relied on the hydric environment.
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Affiliation(s)
- C.A. Galindo
- Grupo de Herpetología, Eco-Fisiología y Etología, Universidad del Tolima, Ibagué, Colombia
- Grupo de Herpetología, Eco-Fisiología y Etología, Universidad del Tolima, Ibagué, Colombia
| | - E.X. Cruz
- Grupo de Herpetología, Eco-Fisiología y Etología, Universidad del Tolima, Ibagué, Colombia
- Grupo de Herpetología, Eco-Fisiología y Etología, Universidad del Tolima, Ibagué, Colombia
| | - M.H. Bernal
- Grupo de Herpetología, Eco-Fisiología y Etología, Universidad del Tolima, Ibagué, Colombia
- Grupo de Herpetología, Eco-Fisiología y Etología, Universidad del Tolima, Ibagué, Colombia
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25
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Birk MA, Dymowska AK, Seibel BA. Do squid breathe through their skin? ACTA ACUST UNITED AC 2018; 221:jeb.185553. [PMID: 30111556 DOI: 10.1242/jeb.185553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/07/2018] [Indexed: 01/13/2023]
Abstract
Squid are thought to obtain a large portion of their oxygen via simple diffusion across the skin in addition to uptake at the gills. Although this hypothesis has support from indirect evidence and is widely accepted, no empirical examinations have been conducted to assess the validity of this hypothesis. In this study, we examined cutaneous respiration in two squid species, Doryteuthis pealeii and Lolliguncula brevis, using a divided chamber to physically separate the mantle cavity and gills from the outer mantle surface. We measured oxygen consumption and ammonia excretion rates in the two compartments and found that, at rest, squid only obtain enough oxygen cutaneously to meet the demand of the skin tissue locally (12% of total) and excrete little ammonia across the skin. The majority of oxygen is obtained via the traditional branchial pathway. In light of these findings, we re-examine and discuss the indirect evidence that has supported the cutaneous respiration hypothesis.
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Affiliation(s)
- Matthew A Birk
- College of Marine Science, University of South Florida, Saint Petersburg, FL 33701, USA
| | - Agnieszka K Dymowska
- College of Marine Science, University of South Florida, Saint Petersburg, FL 33701, USA
| | - Brad A Seibel
- College of Marine Science, University of South Florida, Saint Petersburg, FL 33701, USA
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26
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Lewis ZR, Dorantes JA, Hanken J. Expression of a novel surfactant protein gene is associated with sites of extrapulmonary respiration in a lungless salamander. Proc Biol Sci 2018; 285:rspb.2018.1589. [PMID: 30282653 PMCID: PMC6191699 DOI: 10.1098/rspb.2018.1589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/05/2018] [Indexed: 01/10/2023] Open
Abstract
Numerous physiological and morphological adaptations were achieved during the transition to lungless respiration that accompanied evolutionary lung loss in plethodontid salamanders, including those that enable efficient gas exchange across extrapulmonary tissue. However, the molecular basis of these adaptations is unknown. Here, we show that lungless salamanders express in the larval integument and the adult buccopharynx—principal sites of respiratory gas exchange in these species—a novel paralogue of the gene surfactant-associated protein C (SFTPC), which is a critical component of pulmonary surfactant expressed exclusively in the lung in other vertebrates. The paralogous gene appears to be found only in salamanders, but, similar to SFTPC, in lunged salamanders it is expressed only in the lung. This heterotopic gene expression, combined with predictions from structural modelling and respiratory tissue ultrastructure, suggests that lungless salamanders may produce pulmonary surfactant-like secretions outside the lungs and that the novel paralogue of SFTPC might facilitate extrapulmonary respiration in the absence of lungs. Heterotopic expression of the SFTPC paralogue may have contributed to the remarkable evolutionary radiation of lungless salamanders, which account for more than two thirds of urodele species alive today.
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Affiliation(s)
- Zachary R Lewis
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Jorge A Dorantes
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - James Hanken
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
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27
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Pires DAT, Arake LMR, Silva LP, Lopez-Castillo A, Prates MV, Nascimento CJ, Bloch C. A previously undescribed hexapeptide His-Arg-Phe-Leu-Arg-His-NH 2 from amphibian skin secretion shows CO 2 and metal biding affinities. Peptides 2018; 106:37-44. [PMID: 29933027 DOI: 10.1016/j.peptides.2018.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 06/16/2018] [Accepted: 06/18/2018] [Indexed: 10/28/2022]
Abstract
A previously undescribed six residues long peptide His-Arg-Phe-Leu-Arg-His was identified and purified from the skin secretion of the amphibian Phyllomedusa centralis. A synthetic analogue carboxyamidated HRFLRH-NH2 showed structural changes induced by CO2 and metal ions in aqueous solution when analyzed by NMR. The present work reports NMR structures for the carboxyamidated hexapeptide in the presence CO2, Zn2+ and Cd2+, suggesting possible affinity regions on the polypeptide chain for each ligand. The NMR structures were optimized by DFT to identify probable biding sites of these species in the polypeptide structure. To our best knowledge, this is the first time that a putative CO2 binding site is described on a peptide structure obtained in aqueous conditions, at room temperature.
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Affiliation(s)
- Diego A T Pires
- Instituto de Química, Universidade de Brasília (UnB), Brasília, Distrito Federal, Brazil; Departamento de Áreas Acadêmicas, Instituto Federal de Educação, Ciência e Tecnologia e Goiás (IFG), Luziânia, Goiás, Brazil
| | - Luisa M R Arake
- Laboratório de Espectrometria de Massa, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil
| | - Luciano P Silva
- Laboratório de Espectrometria de Massa, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil
| | - Alejandro Lopez-Castillo
- Departamento de Química, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Maura V Prates
- Laboratório de Espectrometria de Massa, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil
| | - Claudia J Nascimento
- Instituto de Química, Universidade de Brasília (UnB), Brasília, Distrito Federal, Brazil; Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carlos Bloch
- Laboratório de Espectrometria de Massa, Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
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28
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Ferner K. Skin structure in newborn marsupials with focus on cutaneous gas exchange. J Anat 2018; 233:311-327. [PMID: 29947022 PMCID: PMC6081501 DOI: 10.1111/joa.12843] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2018] [Indexed: 12/16/2022] Open
Abstract
A morphological and morphometric study of the skin of a variety of newborn marsupials (Dasyurus viverrinus, Monodelphis domestica, Trichosurus vulpecula, Isoodon obesulus, Perameles nasuta, Phascolarctos cinereus, Potorous tridactylus, Petrogale penicillata, Thylogale thetidi, Macropus dorsalis) and of a monotreme hatchling (Ornithorhynchus anatinus) was undertaken to assess the possibility of cutaneous gas exchange. Additionally, the lungs of some of these species were investigated to assess its structural degree at birth. The skin in the different newborn marsupials and the monotreme hatchling had a similar structure (no hair follicles and no sebaceous or perspiratory glands) and was in all cases less developed than the skin of altricial eutherians. The thickness of the entire skin (36-186 μm) and its different layers, epidermis (6-29 μm) and dermis (29-171 μm) varied among the marsupial species and reflected the differences in size and developmental degree of the neonates. In the skin of all marsupial neonates and the monotreme hatchling, numerous superficial cutaneous capillaries were encountered, some closely associated with the epidermis, indicating the possibility that the skin participated in gaseous exchange. The skin of the newborn D. viverrinus had the highest capillary volume density and shortest skin diffusion barrier of all marsupial neonates, suggesting that skin gas exchange in the dasyurid neonate might be the most pronounced. A graduation of the skin capillary density among the marsupial neonates inversely followed the respective lung structure and general developmental degree of the neonates.
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Affiliation(s)
- Kirsten Ferner
- Museum für NaturkundeLeibniz‐Institut für Evolutions‐ und BiodiversitätsforschungBerlinGermany
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29
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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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Li G, Lv X, Zhou J, Shen C, Xia D, Xie H, Luo Y. Are the surface areas of the gills and body involved with changing metabolic scaling with temperature? ACTA ACUST UNITED AC 2018; 221:jeb.174474. [PMID: 29559548 DOI: 10.1242/jeb.174474] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/13/2018] [Indexed: 01/04/2023]
Abstract
The metabolic-level boundaries (MLB) hypothesis proposes that metabolic level mediates the relative influence of surface area (SA)- versus volume-related metabolic processes on the body-mass scaling of metabolic rate in organisms. The variation in the scaling of SA may affect how metabolic level affects the metabolic scaling exponent. This study aimed to determine the influence of increasing metabolic level at a higher temperature on the metabolic scaling exponent of the goldfish and determine the link between metabolic scaling exponents and SA parameters of both gills and body. The SA of gills and body and the resting metabolic rate (RMR) of the goldfish were assessed at 15°C and 25°C, and their mass scaling exponents were analyzed. The results showed a significantly higher RMR, with a lower scaling exponent, in the goldfish at a higher temperature. The SA of the gills and the total SA of the fish (TSA) were reduced with the increasing temperature. The scaling exponent of RMR (bRMR) tended to be close to that of the TSA at a higher temperature. This suggests that temperature positively affects metabolic level but negatively affects bRMR The findings support the MLB hypothesis. The lower scaling exponent at a higher temperature can be alternatively explained as follows: the higher viscosity of cold water impedes respiratory ventilation and oxygen uptake and reduces metabolic rate more in smaller individuals than in larger individuals at lower temperature, thus resulting in a negative association between temperature and bRMR.
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Affiliation(s)
- Ge Li
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China.,Wudu Bayi High School, Wudu, Longnan, Gansu 746000, China
| | - Xiao Lv
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Jing Zhou
- Department of Clinical Medicine, Chongqing Medical and Pharmaceutical College, Chongqing 401331, China
| | - Cong Shen
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Danyang Xia
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Hang Xie
- Luzhou Agricultural Bureau, National Nature Reserve of Rare and Endemic Fish in the Upper Yangtze River for Luzhou Workstation, Luzhou, Sichuan 646009, China
| | - Yiping Luo
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China
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31
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Tattersall GJ, Burggren WW. Xenopus and the art of oxygen maintenance. J Exp Biol 2017; 220:4084-4087. [PMID: 29141876 DOI: 10.1242/jeb.160697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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32
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Heffell Q, Turko AJ, Wright PA. Plasticity of skin water permeability and skin thickness in the amphibious mangrove rivulus Kryptolebias marmoratus. J Comp Physiol B 2017; 188:305-314. [PMID: 28940028 DOI: 10.1007/s00360-017-1123-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/29/2017] [Accepted: 09/11/2017] [Indexed: 01/29/2023]
Abstract
The skin of amphibious fishes is a multipurpose organ, important for gas and ion exchange and nitrogen excretion when fish are out of water (emersed). We tested the hypothesis that skin permeability is altered to maintain water balance through changes in water permeability and skin thickness during salinity acclimation and/or when fish emerse, using the euryhaline, amphibious fish Kryptolebias marmoratus as a model. We first recorded the behaviour of fish out of water to determine which part of the cutaneous surface was in contact with the substrate. Fish spent about 70% of their time on their ventral surface when out of water. Osmotic permeability of the skin was assessed in fish acclimated to 0.3 or 45‰ using 3H2O fluxes in an in vitro micro-Ussing chamber setup. In freshwater-acclimated fish, 3H2O influx across the skin was significantly higher compared to hypersaline-acclimated fish, with no significant changes in efflux. Prolonged emersion (7 days) resulted in an increase in skin 3H2O influx, but not efflux in fish acclimated to a moist 45‰ substrate. In a separate experiment, dorsal epidermal skin thickness increased while the ventral dermis thickness decreased in fish emersed for over a week. However, there was no link between regional skin thickness and water flux in our experiments. Taken together, these findings suggest that K. marmoratus alter skin permeability to maximize water uptake while emersed in hypersaline conditions, adjustments that probably help them survive months of emersion during the dry season when drinking to replace water loss is not possible.
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Affiliation(s)
- Quentin Heffell
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Andy J Turko
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
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Buser TJ, Burns MD, López JA. Littorally adaptive? Testing the link between habitat, morphology, and reproduction in the intertidal sculpin subfamily Oligocottinae (Pisces: Cottoidea). PeerJ 2017; 5:e3634. [PMID: 28828246 PMCID: PMC5554603 DOI: 10.7717/peerj.3634] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/11/2017] [Indexed: 11/24/2022] Open
Abstract
While intertidal habitats are often productive, species-rich environments, they are also harsh and highly dynamic. Organisms that live in these habitats must possess morphological and physiological adaptations that enable them to do so. Intertidal fishes are generally small, often lack scales, and the diverse families represented in intertidal habitats often show convergence into a few general body shapes. However, few studies have quantified the relationship between phenotypes and intertidal living. Likewise, the diversity of reproductive traits and parental care in intertidal fishes has yet to be compared quantitatively with habitat. We examine the relationship of these characters in the sculpin subfamily Oligocottinae using a phylogenetic hypothesis, geometric morphometrics, and phylogenetic comparative methods to provide the first formal test of associations between fish phenotypes and reproductive characters with intertidal habitats. We show that the ability to live in intertidal habitats, particularly in tide pools, is likely a primitive state for Oligocottinae, with a single species that has secondarily come to occupy only subtidal habitats. Contrary to previous hypotheses, maximum size and presence of scales do not show a statistically significant correlation with depth. However, the maximum size for all species is generally small (250 mm or less) and all show a reduction in scales, as would be expected for an intertidal group. Also contrary to previous hypotheses, we show that copulation and associated characters are the ancestral condition in Oligocottinae, with copulation most likely being lost in a single lineage within the genus Artedius. Lastly, we show that body shape appears to be constrained among species with broader depth ranges, but lineages that occupy only a narrow range of intertidal habitats display novel body shapes, and this may be associated with habitat partitioning, particularly as it relates to the degree of wave exposure.
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Affiliation(s)
- Thaddaeus J. Buser
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America
| | - Michael D. Burns
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, United States of America
| | - J. Andrés López
- College of Fisheries and Ocean Sciences, University of Alaska—Fairbanks, Fairbanks, AK, United States of America
- University of Alaska Museum, Fairbanks, AK, United States of America
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34
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Herrmann SK, Roberts JA. Dehydration resistance and tolerance in the brush-legged wolf spider ( Schizocosaocreata): a comparison of survivorship, critical body water content, and water-loss rates between sexes. CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Small-bodied terrestrial animals like spiders face challenges maintaining water reserves essential for homeostasis. They may experience dry microclimates and (or) seasonal variation in water availability, so dehydration is a common stressor that may help explain movement, foraging, and other behaviors. This study examines aspects of dehydration resistance and tolerance in the brush-legged wolf spider, Schizocosa ocreata (Hentz, 1844) (Araneae: Lycosidae), commonly found in the leaf litter of eastern deciduous forests of North America. Sexes differ in morphology, physiology, reproductive strategy, and life history, likely resulting in divergent abilities to resist and tolerate dehydration. We used humidity-controlled chambers to examine relative survivorship by sex under varying humidity regimes, water-loss rates, body water content, and critical water mass. Spiders survived significantly longer in higher humidity regimes (≥50% RH). Females had significantly better survivorship overall, lower body-loss rates, and lower critical mass, though males had greater percent body water content, indicating that females have greater dehydration resistance and tolerance than males. Although sex-based differences in survival time and water-loss rates are likely an effect of relative body mass, females should be more successful than males during periods of episodic drought and are likely selected to survive later in the season while caring for offspring.
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Affiliation(s)
- Samantha K. Herrmann
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, 1515 Museum of Biological Diversity, 1315 Kinnear Road, Columbus, OH 43212, USA
| | - J. Andrew Roberts
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University at Newark, 1179 University Drive, Newark, OH 43055, USA
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Labuz JM, Moraes C, Mertz DR, Leung BM, Takayama S. Building an experimental model of the human body with non-physiological parameters. TECHNOLOGY 2017; 5:42-59. [PMID: 28713851 PMCID: PMC5509033 DOI: 10.1142/s2339547817500029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
New advances in engineering and biomedical technology have enabled recent efforts to capture essential aspects of human physiology in microscale, in-vitro systems. The application of these advances to experimentally model complex processes in an integrated platform - commonly called a 'human-on-a-chip (HOC)' - requires that relevant compartments and parameters be sized correctly relative to each other and to the system as a whole. Empirical observation, theoretical treatments of resource distribution systems and natural experiments can all be used to inform rational design of such a system, but technical and fundamental challenges (e.g. small system blood volumes and context-dependent cell metabolism, respectively) pose substantial, unaddressed obstacles. Here, we put forth two fundamental principles for HOC design: inducing in-vivo-like cellular metabolic rates is necessary and may be accomplished in-vitro by limiting O2 availability and that the effects of increased blood volumes on drug concentration can be mitigated through pharmacokinetics-based treatments of solute distribution. Combining these principles with natural observation and engineering workarounds, we derive a complete set of design criteria for a practically realizable, physiologically faithful, five-organ millionth-scale (× 10-6) microfluidic model of the human body.
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Affiliation(s)
- Joseph M Labuz
- Department of Biomedical Engineering, College of Engineering and School of Medicine, University of Michigan, 2200 Bonisteel Blvd, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, 2800 Plymouth Road, North Campus Research Complex (NCRC), MI 48109, USA
| | - Christopher Moraes
- Department of Chemical Engineering, Faculty of Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 0C5, Canada
| | - David R Mertz
- Department of Biomedical Engineering, College of Engineering and School of Medicine, University of Michigan, 2200 Bonisteel Blvd, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, 2800 Plymouth Road, North Campus Research Complex (NCRC), MI 48109, USA
| | - Brendan M Leung
- Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, 5981 University Ave, Halifax, Nova Scotia (NS), B3H 4R2, Canada
- School of Biomedical Engineering, Faculties of Medicine and Engineering, Dalhousie University, 5981 University Ave, Halifax, Nova Scotia (NS), B3H 4R2, Canada
| | - Shuichi Takayama
- Department of Biomedical Engineering, College of Engineering and School of Medicine, University of Michigan, 2200 Bonisteel Blvd, Ann Arbor, MI 48109, USA
- Biointerfaces Institute, University of Michigan, 2800 Plymouth Road, North Campus Research Complex (NCRC), MI 48109, USA
- Macromolecular Science and Engineering Center, College of Engineering, University of Michigan, 2300 Hayward St., Ann Arbor, MI 48109, USA
- Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, MI 48109, USA
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36
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Burggren WW, Dubansky B, Bautista NM. Cardiovascular Development in Embryonic and Larval Fishes. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/bs.fp.2017.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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37
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Evidence for Control of Cutaneous Oxygen Uptake in the Yellow-Lipped Sea KraitLaticauda colubrina(Schneider, 1799). J HERPETOL 2016. [DOI: 10.1670/15-037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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38
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Hayward A, Pajuelo M, Haase CG, Anderson DM, Gillooly JF. Common metabolic constraints on dive duration in endothermic and ectothermic vertebrates. PeerJ 2016; 4:e2569. [PMID: 27761347 PMCID: PMC5068442 DOI: 10.7717/peerj.2569] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/14/2016] [Indexed: 11/20/2022] Open
Abstract
Dive duration in air-breathing vertebrates is thought to be constrained by the volume of oxygen stored in the body and the rate at which it is consumed (i.e., "oxygen store/usage hypothesis"). The body mass-dependence of dive duration among endothermic vertebrates is largely supportive of this model, but previous analyses of ectothermic vertebrates show no such body mass-dependence. Here we show that dive duration in both endotherms and ectotherms largely support the oxygen store/usage hypothesis after accounting for the well-established effects of temperature on oxygen consumption rates. Analyses of the body mass and temperature dependence of dive duration in 181 species of endothermic vertebrates and 29 species of ectothermic vertebrates show that dive duration increases as a power law with body mass, and decreases exponentially with increasing temperature. Thus, in the case of ectothermic vertebrates, changes in environmental temperature will likely impact the foraging ecology of divers.
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Affiliation(s)
- April Hayward
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Mariela Pajuelo
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Catherine G. Haase
- School of Natural Resources and Environment, University of Florida, Gainesville, FL, USA
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39
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Ujszegi J, Gál Z, Mikó Z, Hettyey A. No effect of a glyphosate-based herbicide on larval dragonflies (Aeshna cyanea) and adult newts (Lissotriton vulgaris) in a laboratory-based experiment. ACTA ZOOL ACAD SCI H 2016. [DOI: 10.17109/azh.62.4.355.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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40
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Wagner N, Lötters S, Veith M, Viertel B. Acute Toxic Effects of the Herbicide Formulation Focus(®) Ultra on Embryos and Larvae of the Moroccan Painted Frog, Discoglossus scovazzi. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2015; 69:535-544. [PMID: 26118991 DOI: 10.1007/s00244-015-0176-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 06/06/2015] [Indexed: 06/04/2023]
Abstract
For regulatory and scientific purposes, there is a need to understand the sensitivity of a wider variety of wild species of amphibians and the sensitivities within their life stages to chemicals of widespread use such as herbicides. We investigated the acute toxic effects of the herbicide formulation Focus Ultra [with the active ingredient (a.i.) cycloxydim plus solvent naphtha and sodium dioctylsulphosuccinate as added substances] on embryos and early stage larvae of the Moroccan painted frog (Discoglossus scovazzi). Different clinical signs (twitching, convulsion, and narcosis) occurred at 40 and 80 mg/L in embryos (4 and 8 mg a.i./L) and narcotic effects (total immobilization or irregular escape responses) at 10, 15, and 20 mg/L in larvae (1, 1.5, and 2 mg a.i./L). Growth inhibition (total length), starting at 20 mg/L in embryos and 2.5 mg/L in larvae (2 and 0.25 mg a.i./L, respectively) was understood as sign of toxicity (retardation) and not as sign of teratogenicity. However, the connection to teratogenesis remained unclear though total length reduction occurred at concentrations <20 % of the 96-h LC50 value and at a minimum concentration that inhibits growth of only 17 % of the 96-h LC50 value. Starting at 20 mg/L, mortality in embryos significantly increased and at 15 mg/L in early larvae (2 and 1.5 mg a.i./L, respectively). Mortality of larvae was enhanced during the first 24 h of exposure to 15 and 20 mg/L (1.5 and 2 mg a.i./L). Morphology of the embryos remained unobtrusive. In contrary, axial malformations significantly increased in the early larvae starting at 10 mg/L (1 mg a.i./L), a concentration free of lethal effects. In all considered end points, larvae were significantly more sensitive than embryos, probably because of developmental and physiological properties or different exposure and bioavailability of the compound. Focus Ultra induced comparable lethal and immobilization effects in D. scovazzi as it does to standard test organisms in pesticide approval. However, to validate the apparent safety in the field, which is based on calculated surface water concentrations of the a.i., more data on real contamination levels is necessary (e.g., peak concentrations, concentrations of added substances). Furthermore, sufficient buffer strips between the farmland and amphibian ponds must be considered, and the effects of the substance on terrestrial life stages have not been assessed yet.
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Affiliation(s)
- Norman Wagner
- Department of Biogeography, Faculty of Regional and Environmental Sciences, Trier University, Universitätsring 15, 54296, Trier, Germany.
| | - Stefan Lötters
- Department of Biogeography, Faculty of Regional and Environmental Sciences, Trier University, Universitätsring 15, 54296, Trier, Germany
| | - Michael Veith
- Department of Biogeography, Faculty of Regional and Environmental Sciences, Trier University, Universitätsring 15, 54296, Trier, Germany
| | - Bruno Viertel
- Department of Biogeography, Faculty of Regional and Environmental Sciences, Trier University, Universitätsring 15, 54296, Trier, Germany
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41
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Shute L, Huebner E, Anderson WG. Microscopic identification of novel cell types in the integument of larval lake sturgeon, Acipenser fulvescens. J Morphol 2015; 277:86-95. [PMID: 26440535 DOI: 10.1002/jmor.20480] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 08/12/2015] [Accepted: 08/23/2015] [Indexed: 11/10/2022]
Abstract
Osmoregulation, respiration, nutrient/mineral transport, and defense mechanisms are all evident in the integument of fish. The role of the integument in these physiological processes is particularly important during early life history in larval fishes, as functional systems such as the gills and gastrointestinal tract are not fully developed. Using a variety of microscopy techniques, we describe the morphology of keratinocytes, mitochondria rich cells, ciliated cells and mucous cells of the skin, yolk sac, and gills. The cytology we observed was similar to previous studies describing the integument of larval fish, however, we have also identified two novel cell types on the integument of larval Lake Sturgeon, Acipenser fulvescens, between 9 and 34 days post fertilization. Our detailed analysis included a multifaceted microscopy approach using scanning electron, transmission electron, and light microscopy to elucidate the histology of the tissue and cellular morphology in addition to quantification and distribution of these novel cell types. The first cell type had a characteristic ampullary shape with a central cavity and a pore opening at the surface. The second, located on the free surface of the epidermis, had an uneven plasma membrane surface. Based on the abundance of secretory vesicles, organelles necessary for protein synthesis, and the lack of neural connection in both cell types, we propose these cells to be involved in the release of semiochemicals that may act as a pheromone, alarm substance, or chemical defense mechanism.
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Affiliation(s)
- Lauren Shute
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada, Manitoba, R3T 2N2
| | - Erwin Huebner
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada, Manitoba, R3T 2N2
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, Canada, Manitoba, R3T 2N2
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42
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Wagner N, Lötters S, Veith M, Viertel B. Acute toxic effects of the herbicide formulation and the active ingredient used in cycloxydim-tolerant maize cultivation on embryos and larvae of the African clawed frog, Xenopus laevis. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2015; 94:412-418. [PMID: 25634323 DOI: 10.1007/s00128-015-1474-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 01/22/2015] [Indexed: 06/04/2023]
Abstract
Most genetically engineered herbicide-tolerant crops are still awaiting approval in Europe. There is, however, a recent trend for the cultivation of cycloxydim-tolerant maize hybrids for use in maize production. We studied the acute toxic effects of the complementary herbicide Focus(®) Ultra and its active ingredient cycloxydim on embryos and early-stage larvae of the African clawed frog (Xenopus laevis). The results indicate that the herbicide formulation is significantly more toxic than the active ingredient alone. Therefore, it is suggested that the added substances either solely or in a synergistic action with the active ingredient are responsible for adverse effects. The formulation was found to be moderately toxic to embryos but highly toxic to early larvae. Based on calculated teratogenic indices, both cycloxydim and Focus(®) Ultra seem to be non-teratogenic and also the minimum Focus(®) Ultra concentration to inhibit growth in embryos and larvae was close to the LC50 values. The data suggest that tests with the rainbow trout are not in all cases appropriate to assess the risk in aquatically developing anurans. This is demonstrated by 96-h LC50 values, which are for rainbow trout more than 50- to 20-fold higher than for early X. laevis larvae. However, based on worst-case predicted environmental concentrations for surface waters, there is apparently a large safety margin in field use of Focus(®) Ultra if buffer strips between the farm land and the amphibian habitats are regarded.
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Affiliation(s)
- Norman Wagner
- Department of Biogeography, Trier University, Universitätsring 15, 54296, Trier, Germany,
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43
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Ujszegi J, Gál Z, Mikó Z, Hettyey A. No observable effect of a glyphosate-based herbicide on two top predators of temporal water bodies. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2015; 34:307-13. [PMID: 25378294 DOI: 10.1002/etc.2798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/21/2014] [Accepted: 11/04/2014] [Indexed: 06/04/2023]
Abstract
It has been implied that the application of pesticides is involved in the world-wide decline of biodiversity, but little is known about the influence of these chemicals on key predators of temporary wetlands. The direct impacts were examined of a frequently applied glyphosate-based herbicide on larval Aeshna cyanea (Müller, 1764; Odonata, Insecta) and adult male Lissotriton vulgaris (Linnaeus, 1758; Caudata, Amphibia), 2 top predators of Central European ephemeral ponds. The effects of herbicide exposure were measured on survival, behavior, body mass change, and predatory activity in an outdoor mesocosm experiment lasting for 17 d. No significant effects of exposure were observed in either predator species. The results suggest that the herbicide has no immediate effect on the predators studied at environmentally relevant concentrations and that these predators can also fulfill their top-down regulatory role in contaminated ecosystems.
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Affiliation(s)
- János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
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44
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Kovalyova IM. Key morphofunctional transformations in the evolution of bats (Mammalia, Chiroptera). Russ J Dev Biol 2014. [DOI: 10.1134/s1062360414060071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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45
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Wardziak T, Oxarango L, Valette S, Mahieu-Williame L, Joly P. Modelling skin surface areas involved in water transfer in the Palmate Newt (Lissotriton helveticus). CAN J ZOOL 2014. [DOI: 10.1139/cjz-2014-0017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Magnetic resonance imaging (MRI) based 3D reconstructions were used to derive accurate quantitative data on body volume and functional skin surface areas involved in water transfer in the Palmate Newt (Lissotriton helveticus (Razoumovsky, 1789)). Body surface area can be functionally divided into evaporative surface area that interacts with the atmosphere and controls the transepidermal evaporative water loss (TEWL); ventral surface area in contact with the substratum that controls transepidermal water absorption (TWA); and skin surface area in contact with other skin surfaces when amphibians adopt water-conserving postures. We generated 3D geometries of the newts via volume-rendering by a “segmentation” process carried out using a graph-cuts algorithm and a Web-based interface. The geometries reproduced the two postures adopted by the newts, i.e., an I-shaped posture characterized by a straight body without tail coiling and an S-shaped posture where the body is huddled up with the tail coiling along it. As a guide to the quality of the surface area estimations, we compared measurements of TEWL rates between living newts and their agar replicas (reproducing their two postures) at 20 °C and 60% relative humidity. Whereas the newts did not show any physiological adaptations to restrain evaporation, they expressed an efficient S-shaped posture with a resulting water economy of 22.9%, which is very close to the 23.6% reduction in evaporative surface area measured using 3D analysis.
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Affiliation(s)
- Thomas Wardziak
- Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE; CNRS; 6 rue Raphaël Dubois, 69622 Villeurbanne, France
| | - Laurent Oxarango
- LTHE, Université de Grenoble, BP 53, 38041 Grenoble CEDEX, France
| | | | | | - Pierre Joly
- Université de Lyon, UMR 5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, Université Lyon 1, ENTPE; CNRS; 6 rue Raphaël Dubois, 69622 Villeurbanne, France
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46
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Bowden AJ, Gardiner NM, Couturier CS, Stecyk JAW, Nilsson GE, Munday PL, Rummer JL. Alterations in gill structure in tropical reef fishes as a result of elevated temperatures. Comp Biochem Physiol A Mol Integr Physiol 2014; 175:64-71. [PMID: 24862962 DOI: 10.1016/j.cbpa.2014.05.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 05/13/2014] [Accepted: 05/16/2014] [Indexed: 11/25/2022]
Abstract
Tropical regions are expected to be some of the most affected by rising sea surface temperatures (SSTs) because seasonal temperature variations are minimal. As temperatures rise, less oxygen dissolves in water, but metabolic requirements of fish and thus, the demand for effective oxygen uptake, increase. Gill remodelling is an acclimation strategy well documented in freshwater cyprinids experiencing large seasonal variations in temperature and oxygen as well as an amphibious killifish upon air exposure. However, no study has investigated whether tropical reef fishes remodel their gills to allow for increased oxygen demands at elevated temperatures. We tested for gill remodelling in five coral reef species (Acanthochromis polyacanthus, Chromis atripectoralis, Pomacentrus moluccensis, Dascyllus melanurus and Cheilodipterus quinquelineatus) from populations in northern Papua New Guinea (2° 35.765' S; 150° 46.193' E). Fishes were acclimated for 12-14 days to 29 and 31°C (representing their seasonal range) and 33 and 34°C to account for end-of-century predicted temperatures. We measured lamellar perimeter, cross-sectional area, base thickness, and length for five filaments on the 2nd gill arches and qualitatively assessed 3rd gill arches via scanning electron microscopy (SEM). All species exhibited significant differences in the quantitative measurements made on the lamellae, but no consistent trends with temperature were observed. SEM only revealed alterations in gill morphology in P. moluccensis. The overall lack of changes in gill morphology with increasing temperature suggests that these near-equatorial reef fishes may fail to maintain adequate O2 uptake under future climate scenarios unless other adaptive mechanisms are employed.
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Affiliation(s)
- A J Bowden
- School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
| | - N M Gardiner
- School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia
| | - C S Couturier
- Programme for Physiology and Neurobiology, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - J A W Stecyk
- Programme for Physiology and Neurobiology, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway; Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - G E Nilsson
- Programme for Physiology and Neurobiology, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - P L Munday
- School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia; ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - J L Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
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Martin KL. Theme and variations: amphibious air-breathing intertidal fishes. JOURNAL OF FISH BIOLOGY 2014; 84:577-602. [PMID: 24344914 DOI: 10.1111/jfb.12270] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 10/05/2013] [Indexed: 05/23/2023]
Abstract
Over 70 species of intertidal fishes from 12 families breathe air while emerging from water. Amphibious intertidal fishes generally have no specialized air-breathing organ but rely on vascularized mucosae and cutaneous surfaces in air to exchange both oxygen and carbon dioxide. They differ from air-breathing freshwater fishes in morphology, physiology, ecology and behaviour. Air breathing and terrestrial activity are present to varying degrees in intertidal fish species, correlated with the tidal height of their habitat. The gradient of amphibious lifestyle includes passive remainers that stay in the intertidal zone as tides ebb, active emergers that deliberately leave water in response to poor aquatic conditions and highly mobile amphibious skipper fishes that may spend more time out of water than in it. Normal terrestrial activity is usually aerobic and metabolic rates in air and water are similar. Anaerobic metabolism may be employed during forced exercise or when exposed to aquatic hypoxia. Adaptations for amphibious life include reductions in gill surface area, increased reliance on the skin for respiration and ion exchange, high affinity of haemoglobin for oxygen and adjustments to ventilation and metabolism while in air. Intertidal fishes remain close to water and do not travel far terrestrially, and are unlikely to migrate or colonize new habitats at present, although in the past this may have happened. Many fish species spawn in the intertidal zone, including some that do not breathe air, as eggs and embryos that develop in the intertidal zone benefit from tidal air emergence. With air breathing, amphibious intertidal fishes survive in a variable habitat with minimal adjustments to existing structures. Closely related species in different microhabitats provide unique opportunities for comparative studies.
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Affiliation(s)
- K L Martin
- Department of Biology, 24255 Pacific Coast Highway, Pepperdine University, Malibu, CA 90263-4321, U.S.A
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Malte CL, Malte H, Wang T. Episodic ventilation lowers the efficiency of pulmonary CO2 excretion. J Appl Physiol (1985) 2013; 115:1506-18. [DOI: 10.1152/japplphysiol.00808.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ventilation pattern of many ectothermic vertebrates, as well as hibernating and diving endotherms, is episodic where breaths are clustered in bouts interspersed among apneas of varying duration. Using mechanically ventilated, anesthetized freshwater turtles ( Trachemys scripta), a species that normally exhibits this episodic ventilation pattern, we investigated whether episodic ventilation affects pulmonary gas exchange compared with evenly spaced breaths. In two separate series of experiments (a noninvasive and an invasive), ventilation pattern was switched from a steady state, with evenly spaced breaths, to episodic ventilation while maintaining overall minute ventilation (30 ml·min−1·kg−1). On switching to an episodic ventilation pattern of 10 clustered breaths, mean CO2 excretion rate was reduced by 6 ± 5% (noninvasive protocol) or 20 ± 8% (invasive protocol) in the first ventilation pattern cycle, along with a reduction in the respiratory exchange ratio. O2 uptake was either not affected or increased in the first ventilation pattern cycle, while neither heart rate nor overall pulmonary blood flow was significantly affected by the ventilation patterns. The results confirm that, for a given minute ventilation, episodic ventilation is intrinsically less efficient for CO2 excretion, thereby indicating an increase in the total bodily CO2 store in the protocol. Despite the apparent CO2 retention, mean arterial Pco2 only increased 1 Torr during the episodic ventilation pattern, which was concomitant with a possible reduction of respiratory quotient. This would indicate a shift in metabolism such that less CO2 is produced when the efficiency of excretion is reduced.
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Affiliation(s)
| | - Hans Malte
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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Abstract
Hibernation in endotherms and ectotherms is characterized by an energy-conserving metabolic depression due to low body temperatures and poorly understood temperature-independent mechanisms. Rates of gas exchange are correspondly reduced. In hibernating mammals, ventilation falls even more than metabolic rate leading to a relative respiratory acidosis that may contribute to metabolic depression. Breathing in some mammals becomes episodic and in some small mammals significant apneic gas exchange may occur by passive diffusion via airways or skin. In ectothermic vertebrates, extrapulmonary gas exchange predominates and in reptiles and amphibians hibernating underwater accounts for all gas exchange. In aerated water diffusive exchange permits amphibians and many species of turtles to remain fully aerobic, but hypoxic conditions can challenge many of these animals. Oxygen uptake into blood in both endotherms and ectotherms is enhanced by increased affinity of hemoglobin for O₂ at low temperature. Regulation of gas exchange in hibernating mammals is predominately linked to CO₂/pH, and in episodic breathers, control is principally directed at the duration of the apneic period. Control in submerged hibernating ectotherms is poorly understood, although skin-diffusing capacity may increase under hypoxic conditions. In aerated water blood pH of frogs and turtles either adheres to alphastat regulation (pH ∼8.0) or may even exhibit respiratory alkalosis. Arousal in hibernating mammals leads to restoration of euthermic temperature, metabolic rate, and gas exchange and occurs periodically even as ambient temperatures remain low, whereas body temperature, metabolic rate, and gas exchange of hibernating ectotherms are tightly linked to ambient temperature.
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Affiliation(s)
- William K Milsom
- Department of Zoology, University of British Columbia, 6270 University Blvd., Vancouver, British Columbia, Canada
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50
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Verberk WCEP, Atkinson D. Why polar gigantism and
P
alaeozoic gigantism are not equivalent: effects of oxygen and temperature on the body size of ectotherms. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12152] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wilco C. E. P. Verberk
- Department of Animal Ecology and Ecophysiology Institute for Water and Wetland Research Radboud University P.O. Box 9010 6500 GL Nijmegen the Netherlands
- Marine Biology and Ecology Research Centre School of Marine Science and Engineering University of Plymouth Davy Building Drake Circus Plymouth PL4 8AA UK
| | - David Atkinson
- Department of Evolution, Ecology & Behaviour Biosciences Building Institute of Integrative Biology University of Liverpool Liverpool L69 7ZB UK
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