1
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Harter TS, Dichiera AM, Esbaugh AJ. The physiological significance of plasma-accessible carbonic anhydrase in the respiratory systems of fishes. J Comp Physiol B 2024:10.1007/s00360-024-01562-4. [PMID: 38842596 DOI: 10.1007/s00360-024-01562-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/26/2024] [Accepted: 05/13/2024] [Indexed: 06/07/2024]
Abstract
Carbonic anhydrase (CA) activity is ubiquitously found in all vertebrate species, tissues and cellular compartments. Most species have plasma-accessible CA (paCA) isoforms at the respiratory surfaces, where the enzyme catalyzes the conversion of plasma bicarbonate to carbon dioxide (CO2) that can be excreted by diffusion. A notable exception are the teleost fishes that appear to lack paCA at their gills. The present review: (i) recapitulates the significance of CA activity and distribution in vertebrates; (ii) summarizes the current evidence for the presence or absence of paCA at the gills of fishes, from the basal cyclostomes to the derived teleosts and extremophiles such as the Antarctic icefishes; (iii) explores the contribution of paCA to organismal CO2 excretion in fishes; and (iv) the functional significance of its absence at the gills, for the specialized system of O2 transport in most teleosts; (v) outlines the multiplicity and isoform distribution of membrane-associated CAs in fishes and methodologies to determine their plasma-accessible orientation; and (vi) sketches a tentative time line for the evolutionary dynamics of branchial paCA distribution in the major groups of fishes. Finally, this review highlights current gaps in the knowledge on branchial paCA function and provides recommendations for future work.
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Affiliation(s)
- Till S Harter
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
| | - Angelina M Dichiera
- College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, VA, 23062, USA
| | - Andrew J Esbaugh
- Marine Science Institute, University of Texas at Austin, Port Aransas, TX, 78373, USA
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2
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Kaczmarek EB, Brainerd EL. Buoyancy control and air breathing in royal knifefish (Chitala blanci) and a new hypothesis for the early evolution of vertebrate air-breathing behaviors. Anat Rec (Hoboken) 2024. [PMID: 38711405 DOI: 10.1002/ar.25460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 02/23/2024] [Accepted: 04/01/2024] [Indexed: 05/08/2024]
Abstract
We present the first description of inspiration-first air breaths in royal knifefish, Chitala blanci, a ray-finned fish known to use four-stroke air breaths. Four-stroke breaths are used by nearly all ray-finned fish species that use their gas bladder to breathe air and are the ancestral breath type of ray-finned fishes. Interestingly, one such species, Amia calva, is known to perform two distinct breath types. Amia use four-stroke breaths when they need more oxygen and performs inspiration-first breaths to restore buoyancy. We observed that C. blanci also performs inspiration-first breaths and tested whether the two breath types are performed for the same functions in C. blanci as they are in Amia. We recorded the frequency of each breath type when exposed to aquatic hypoxia and two conditions of oxygen availability. We found that C. blanci performed more four-stroke breaths (81% ± 15% of total breaths) than inspiration-first breaths when exposed to aerial normoxia but performed more inspiration-first breaths (72% ± 40%) than four-stroke breaths when exposed to aerial hyperoxia. These patterns match those described for Amia and indicate that C. blanci performs four-stroke breaths in response to oxygen depletion and performs inspiration-first breaths to maintain buoyancy. Few studies have examined the role of air-breathing in buoyancy regulation. Decreasing buoyancy, rather than oxygen availability, to stimulate air breaths may reveal that inspiration-first breaths are more common among fishes than we are aware. We consider this possibility and present a new hypothesis for the origin and early evolution of air breathing in vertebrates.
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Affiliation(s)
- Elska B Kaczmarek
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Elizabeth L Brainerd
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, USA
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3
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De-Kayne R, Perry BW, McGowan KL, Landers J, Arias-Rodriguez L, Greenway R, Rodríguez Peña CM, Tobler M, Kelley JL. Evolutionary Rate Shifts in Coding and Regulatory Regions Underpin Repeated Adaptation to Sulfidic Streams in Poeciliid Fishes. Genome Biol Evol 2024; 16:evae087. [PMID: 38788745 PMCID: PMC11126329 DOI: 10.1093/gbe/evae087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2024] [Indexed: 05/26/2024] Open
Abstract
Adaptation to extreme environments often involves the evolution of dramatic physiological changes. To better understand how organisms evolve these complex phenotypic changes, the repeatability and predictability of evolution, and possible constraints on adapting to an extreme environment, it is important to understand how adaptive variation has evolved. Poeciliid fishes represent a particularly fruitful study system for investigations of adaptation to extreme environments due to their repeated colonization of toxic hydrogen sulfide-rich springs across multiple species within the clade. Previous investigations have highlighted changes in the physiology and gene expression in specific species that are thought to facilitate adaptation to hydrogen sulfide-rich springs. However, the presence of adaptive nucleotide variation in coding and regulatory regions and the degree to which convergent evolution has shaped the genomic regions underpinning sulfide tolerance across taxa are unknown. By sampling across seven independent lineages in which nonsulfidic lineages have colonized and adapted to sulfide springs, we reveal signatures of shared evolutionary rate shifts across the genome. We found evidence of genes, promoters, and putative enhancer regions associated with both increased and decreased convergent evolutionary rate shifts in hydrogen sulfide-adapted lineages. Our analysis highlights convergent evolutionary rate shifts in sulfidic lineages associated with the modulation of endogenous hydrogen sulfide production and hydrogen sulfide detoxification. We also found that regions with shifted evolutionary rates in sulfide spring fishes more often exhibited convergent shifts in either the coding region or the regulatory sequence of a given gene, rather than both.
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Affiliation(s)
- Rishi De-Kayne
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
| | - Blair W Perry
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Kerry L McGowan
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Jake Landers
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Lenin Arias-Rodriguez
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco (UJAT), Villahermosa, México
| | - Ryan Greenway
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Carlos M Rodríguez Peña
- Instituto de Investigaciones Botánicas y Zoológicas, Universidad Autónoma de Santo Domingo, Santo Domingo 10105, Dominican Republic
| | - Michael Tobler
- Department of Biology, University of Missouri–St. Louis, St. Louis, MO 63131, USA
- Whitney R. Harris World Ecology Center, University of Missouri–St. Louis, St. Louis, MO 63121, USA
- WildCare Institute, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Joanna L Kelley
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA 95060, USA
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4
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Szabó N, Fodor E, Varga Z, Tarján-Rácz A, Szabó K, Miklósi Á, Varga M. The paradise fish, an advanced animal model for behavioral genetics and evolutionary developmental biology. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:189-199. [PMID: 37818738 DOI: 10.1002/jez.b.23223] [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: 05/31/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 10/13/2023]
Abstract
Paradise fish (Macropodus opercularis) is an air-breathing freshwater fish species with a signature labyrinth organ capable of extracting oxygen from the air that helps these fish to survive in hypoxic environments. The appearance of this evolutionary innovation in anabantoids resulted in a rewired circulatory system, but also in the emergence of species-specific behaviors, such as territorial display, courtship and parental care in the case of the paradise fish. Early zoologists were intrigued by the structure and function of the labyrinth apparatus and a series of detailed descriptive histological studies at the beginning of the 20th century revealed the ontogenesis and function of this specialized system. A few decades later, these fish became the subject of numerous ethological studies, and detailed ethograms of their behavior were constructed. These latter studies also demonstrated a strong genetic component underlying their behavior, but due to lack of adequate molecular tools, the fine genetic dissection of the behavior was not possible at the time. The technological breakthroughs that transformed developmental biology and behavioral genetics in the past decades, however, give us now a unique opportunity to revisit these old questions. Building on the classic descriptive studies, the new methodologies will allow us to follow the development of the labyrinth apparatus at a cellular resolution, reveal the genes involved in this process and also the genetic architecture behind the complex behaviors that we can observe in this species.
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Affiliation(s)
- Nóra Szabó
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Erika Fodor
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Zoltán Varga
- Laboratory of Translational Behavioural Neuroscience, Department of Behavioural Neurobiology, Institute of Experimental Medicine, Eötvös Loránd Research Network, Budapest, Hungary
| | - Anita Tarján-Rácz
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Kata Szabó
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Ádám Miklósi
- Department of Ethology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Máté Varga
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
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5
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Young SJ, Rossi GS, Bernier NJ, Wright PA. Cortisol enhances aerobic metabolism and locomotor performance during the transition to land in an amphibious fish. Comp Biochem Physiol A Mol Integr Physiol 2024; 288:111558. [PMID: 38043639 DOI: 10.1016/j.cbpa.2023.111558] [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: 09/12/2023] [Revised: 11/10/2023] [Accepted: 11/28/2023] [Indexed: 12/05/2023]
Abstract
Amphibious fishes on land encounter higher oxygen (O2) availability and novel energetic demands, which impacts metabolism. Previous work on the amphibious mangrove killifish (Kryptolebias marmoratus) has shown that cortisol becomes elevated in response to air exposure, suggesting a possible role in regulating metabolism as fish move into terrestrial environments. We tested the hypothesis that cortisol is the mechanism by which oxidative processes are upregulated during the transition to land in amphibious fishes. We used two groups of fish, treated fish (+metyrapone, a cortisol synthesis inhibitor) and control (-metyrapone), to determine the impact of cortisol during air exposure (0 and 1 h, 7 days) on O2 consumption, terrestrial locomotion, the phenotype of red skeletal muscle, and muscle lipid concentration. Metyrapone-treated fish had an attenuated elevation in O2 consumption rate during the water to air transition and an immediate reduction in terrestrial exercise performance relative to control fish. In contrast, we found no short- (0 h) or long-term (7 days) differences between treatments in the oxidative phenotype of red muscles, nor in muscle lipid concentrations. Our results suggest that cortisol stimulates the necessary increase in aerobic metabolism needed to fuel the physiological changes that amphibious fishes undergo during the acclimation to air, although further studies are required to determine specific mechanisms of cortisol regulation.
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Affiliation(s)
- Sarah J Young
- University of Guelph, Department of Integrative Biology, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; Saint Mary's University, Department of Biology, 923 Robie Street, Halifax, NS B3H 3C3, Canada.
| | - Giulia S Rossi
- University of Toronto-Scarborough, Department of Biological Science, 1265 Military Trail, Scarborough, ON M1C 1A4, Canada; McMaster University, Biology Department, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada.
| | - Nicholas J Bernier
- University of Guelph, Department of Integrative Biology, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.
| | - Patricia A Wright
- University of Guelph, Department of Integrative Biology, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.
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6
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Aaskov ML, Nelson D, Lauridsen H, Huong DTT, Ishimatsu A, Crossley DA, Malte H, Bayley M. Do air-breathing fish suffer branchial oxygen loss in hypoxic water? Proc Biol Sci 2023; 290:20231353. [PMID: 37700647 PMCID: PMC10498054 DOI: 10.1098/rspb.2023.1353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
In hypoxia, air-breathing fish obtain O2 from the air but continue to excrete CO2 into the water. Consequently, it is believed that some O2 obtained by air-breathing is lost at the gills in hypoxic water. Pangasionodon hypophthalmus is an air-breathing catfish with very large gills from the Mekong River basin where it is cultured in hypoxic ponds. To understand how P. hypophthalmus can maintain high growth in hypoxia with the presumed O2 loss, we quantified respiratory gas exchange in air and water. In severe hypoxia (PO2: ≈ 1.5 mmHg), it lost a mere 4.9% of its aerial O2 uptake, while maintaining aquatic CO2 excretion at 91% of the total. Further, even small elevations in water PO2 rapidly reduced this minor loss. Charting the cardiovascular bauplan across the branchial basket showed four ventral aortas leaving the bulbus arteriosus, with the first and second gill arches draining into the dorsal aorta while the third and fourth gill arches drain into the coeliacomesenteric artery supplying the gut and the highly trabeculated respiratory swim-bladder. Substantial flow changes across these two arterial systems from normoxic to hypoxic water were not found. We conclude that the proposed branchial oxygen loss in air-breathing fish is likely only a minor inefficiency.
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Affiliation(s)
- Magnus L. Aaskov
- Division of Zoophysiology, Department of Biology, Aarhus University, 8000C Aarhus, Denmark
| | - Derek Nelson
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA
| | - Henrik Lauridsen
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus, Denmark
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Atsushi Ishimatsu
- Institute for East China Sea Research, Nagasaki University, Nagasaki, Japan
| | - Dane A. Crossley
- Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, USA
| | - Hans Malte
- Division of Zoophysiology, Department of Biology, Aarhus University, 8000C Aarhus, Denmark
| | - Mark Bayley
- Division of Zoophysiology, Department of Biology, Aarhus University, 8000C Aarhus, Denmark
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7
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Kimura Y, Nakamuta N, Nikaido M. Plastic loss of motile cilia in the gills of Polypterus in response to high CO 2 or terrestrial environments. Ecol Evol 2023; 13:e9964. [PMID: 37038517 PMCID: PMC10082155 DOI: 10.1002/ece3.9964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 04/12/2023] Open
Abstract
The evolutionary transition of vertebrates from water to land during the Devonian period was accompanied by major changes in animal respiratory systems in terms of physiology and morphology. Indeed, the fossil record of the early tetrapods has revealed the existence of internal gills, which are vestigial fish-like traits used underwater. However, the fossil record provides only limited data on the process of the evolutionary transition of gills from fish to early tetrapods. This study investigated the gills of Polypterus senegalus, a basal ray-finned/amphibious fish which shows many ancestral features of stem Osteichthyes. Based on scanning electron microscopy observations and transcriptome analysis, the existence of motile cilia in the gills was revealed which may create a flow on the gill surface leading to efficient ventilation or remove particles from the surface. Interestingly, these cilia were observed to disappear after rearing in terrestrial or high CO2 environments, which mimics the environmental changes in the Devonian period. The cilia re-appeared after being returned to the original aquatic environment. The ability of plastic changes of gills in Polypterus revealed in this study may allow them to survive in fluctuating environments, such as shallow swamps. The ancestor of Osteichthyes is expected to have possessed such plasticity in the gills, which may be one of the driving forces behind the transition of vertebrates from water to land.
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Affiliation(s)
- Yuki Kimura
- School of Life Science and TechnologyTokyo Institute of TechnologyTokyoJapan
| | | | - Masato Nikaido
- School of Life Science and TechnologyTokyo Institute of TechnologyTokyoJapan
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8
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Tunnah L, Turko AJ, Wright PA. Skin ionocyte density of amphibious killifishes is shaped by phenotypic plasticity and constitutive interspecific differences. J Comp Physiol B 2022; 192:701-711. [PMID: 36056931 DOI: 10.1007/s00360-022-01457-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/13/2022] [Accepted: 08/18/2022] [Indexed: 11/24/2022]
Abstract
When amphibious fishes are on land, gill function is reduced or eliminated and the skin is hypothesized to act as a surrogate site of ionoregulation. Skin ionocytes are present in many fishes, particularly those with amphibious life histories. We used nine closely related killifishes spanning a range of amphibiousness to first test the hypothesis that amphibious killifishes have evolved constitutively increased skin ionocyte density to promote ionoregulation on land. We found that skin ionocyte densities were constitutively higher in five of seven amphibious species examined relative to exclusively water-breathing species when fish were prevented from leaving water, strongly supporting our hypothesis. Next, to examine the scope for plasticity, we tested the hypothesis that skin ionocyte density in amphibious fishes would respond plastically to air-exposure to promote ionoregulation in terrestrial environments. We found that air-exposure induced plasticity in skin ionocyte density only in the two species classified as highly amphibious, but not in moderately amphibious species. Specifically, skin ionocyte density significantly increased in Anablepsoides hartii (168%) and Kryptolebias marmoratus (37%) following a continuous air-exposure, and only in K. marmoratus (43%) following fluctuating air-exposure. Collectively, our data suggest that highly amphibious killifishes have evolved both increased skin ionocyte density as well as skin that is more responsive to air-exposure compared to exclusively water-breathing and less amphibious species. Our findings are consistent with the idea that gaining the capacity for cutaneous ionoregulation is a key evolutionary step that enables amphibious fishes to survive on land.
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Affiliation(s)
- Louise Tunnah
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Andy J Turko
- Department of Biology, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
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9
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Kaczmarek EB, Gartner SM, Westneat MW, Brainerd EL. Air Breathing and Suction Feeding Kinematics in the West African Lungfish, Protopterus Annectens. Integr Comp Biol 2022; 62:865-877. [PMID: 35798019 DOI: 10.1093/icb/icac109] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 11/13/2022] Open
Abstract
Research on the water-to-land transition tends to focus on the locomotor changes necessary for terrestriality. But the evolution from water breathing to air breathing was also a necessary precursor to the invasion of land. Air is approximately 1,000 times less dense, 50 times less viscous, and contains hundreds of times more oxygen than water. However, unlike the transition to terrestrial locomotion, breathing air does not require body weight support, so the evolution of air breathing may have necessitated smaller changes to morphology and function. We used X-ray Reconstruction of Moving Morphology to compare the cranial kinematics of aquatic buccal pumping, such as seen in suction feeding, with the aerial buccal pumping required for lung ventilation in the West African lungfish (Protopterus annectens). During buccal pumping behaviors, the cranial bones and associated soft tissues act as valves and pumps, and the sequence of their motions controls the pattern of fluid flow. Both behaviors are characterized by an anterior-to-posterior wave of expansion and an anterior-to-posterior wave of compression. We found that the pectoral girdle and cranial rib rotate consistently during air breathing and suction feeding, and that the muscle between them shortens during buccal expansion. Overall, we conclude that the major cranial bones maintain the same basic functions (i.e., acting as valves or pumps, or transmitting power) across aquatic and aerial buccal pumping. The cranial morphology that enables aquatic buccal pumping is well-suited to perform air-breathing and accommodates the physical differences between air and water.
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Affiliation(s)
- Elska B Kaczmarek
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence RI 02912
| | - Samantha M Gartner
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
| | - Mark W Westneat
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637
| | - Elizabeth L Brainerd
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence RI 02912
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10
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Naylor ER, Kawano SM. Mudskippers modulate their locomotor kinematics when moving on deformable and inclined substrates. Integr Comp Biol 2022; 62:icac084. [PMID: 35679069 DOI: 10.1093/icb/icac084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many ecological factors influence animal movement, including properties of the media that they move on or through. Animals moving in terrestrial environments encounter conditions that can be challenging for generating propulsion and maintaining stability, such as inclines and deformable substrates that can cause slipping and sinking. In response, tetrapods tend to adopt a more crouched posture and lower their center of mass on inclines and increase the surface area of contact on deformable substrates, such as sand. Many amphibious fishes encounter the same challenges when moving on land, but how these finned animals modulate their locomotion with respect to different environmental conditions and how these modifications compare with those seen within tetrapods is relatively understudied. Mudskippers (Gobiidae: Oxudercinae) are a particularly noteworthy group of amphibious fishes in this context given that they navigate a wide range of environmental conditions, from flat mud to inclined mangrove trees. They use a unique form of terrestrial locomotion called 'crutching', where their pectoral fins synchronously lift and vault the front half of the body forward before landing on their pelvic fins while the lower half of the body and tail are kept straight. However, recent work has shown that mudskippers modify some aspects of their locomotion when crutching on deformable surfaces, particularly those at an incline. For example, on inclined dry sand, mudskippers bent their bodies laterally and curled and extended their tails to potentially act as a secondary propulsor and/or anti-slip device. In order to gain a more comprehensive understanding of the functional diversity and context-dependency of mudskipper crutching, we compared their kinematics on different combinations of substrate types (solid, mud, dry sand) and inclines (0°, 10°, 20°). In addition to increasing lateral bending on deformable and inclined substrates, we found that mudskippers increased the relative contact time and contact area of their paired fins while becoming more crouched, responses comparable to those seen in tetrapods and other amphibious fishes. Mudskippers on these substrates also exhibited previously undocumented behaviors, such as extending and adpressing the distal portions of their pectoral fins more anteriorly, dorsoventrally bending their trunk, "belly-flopping" on sand, and "gripping" the mud substrate with their pectoral fin rays. Our study highlights potential compensatory mechanisms shared among vertebrates in terrestrial environments while also illustrating that locomotor flexibility and even novelty can emerge when animals are challenged with environmental variation.
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Affiliation(s)
- Emily R Naylor
- Department of Biological Sciences, The George Washington University, Washington, D.C. 20052, U.S.A
| | - Sandy M Kawano
- Department of Biological Sciences, The George Washington University, Washington, D.C. 20052, U.S.A
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11
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Weber RE, Damsgaard C, Fago A, Val AL, Moens L. Ontogeny of hemoglobin‑oxygen binding and multiplicity in the obligate air-breathing fish Arapaima gigas. Comp Biochem Physiol A Mol Integr Physiol 2022; 268:111190. [PMID: 35331911 DOI: 10.1016/j.cbpa.2022.111190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/15/2022] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
Abstract
The evolutionary and ontogenetic changes from water- to air-breathing result in major changes in the cardiorespiratory systems. However, the potential changes in hemoglobin's (Hb) oxygen binding properties during ontogenetic transitions to air-breathing remain poorly understood. Here we investigated Hb multiplicity and O2 binding in hemolysates and Hb components from juveniles and adults of the obligate air-breathing pirarucu (Arapaima gigas) that starts life as water-breathing hatchlings. Contrasting with previous electrophoresis studies that report one or two isoHbs in adults, isoelectric focusing (IEF) resolved the hemolysates from both stages into four major bands, which exhibited identical O2 binding properties (i.e. O2 affinities, cooperativity coefficients, and sensitivities to pH and the major organic phosphate effectors), also as compared to the cofactor-free hemolysates. Of note, the multiplicity pattern recurred upon reanalyses of the most-abundant fractions isolated from the juvenile and the adult stages, suggesting possible stabilization of different quaternary states with different isoelectric points during the purification procedure. The study demonstrates unchanged Hb-O2 binding properties during development, despite the pronounced differences in O2 availability between the two media, which harmonizes with findings based on a broader spectrum of interspecific comparisons. Taken together, these results disclose that obligate air-breathing in Arapaima is not contingent upon changes in Hb multiplicity and O2 binding characteristics.
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Affiliation(s)
- Roy E Weber
- Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark.
| | - Christian Damsgaard
- Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark; Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
| | - Angela Fago
- Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Adalberto L Val
- Brazilian National Institute for Research of the Amazon, Manaus, Amazonas, Brazil
| | - Luc Moens
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
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12
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Lutek K, Donatelli CM, Standen EM. Patterns and processes in amphibious fish: biomechanics and neural control of fish terrestrial locomotion. J Exp Biol 2022; 225:275243. [PMID: 35502693 DOI: 10.1242/jeb.242395] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Amphibiousness in fishes spans the actinopterygian tree from the earliest to the most recently derived species. The land environment requires locomotor force production different from that in water, and a diversity of locomotor modes have evolved across the actinopterygian tree. To compare locomotor mode between species, we mapped biomechanical traits on an established amphibious fish phylogeny. Although the diversity of fish that can move over land is large, we noted several patterns, including the rarity of morphological and locomotor specialization, correlations between body shape and locomotor mode, and an overall tendency for amphibious fish to be small. We suggest two idealized empirical metrics to consider when gauging terrestrial 'success' in fishes and discuss patterns of terrestriality in fishes considering biomechanical scaling, physical consequences of shape, and tissue plasticity. Finally, we suggest four ways in which neural control could change in response to a novel environment, highlighting the importance and challenges of deciphering when these control mechanisms are used. We aim to provide an overview of the diversity of successful amphibious locomotion strategies and suggest several frameworks that can guide the study of amphibious fish and their locomotion.
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Affiliation(s)
- K Lutek
- Department of Biology, University of Ottawa, Ottawa, Canada, K1N 6N5
| | - C M Donatelli
- Department of Biology, University of Ottawa, Ottawa, Canada, K1N 6N5
| | - E M Standen
- Department of Biology, University of Ottawa, Ottawa, Canada, K1N 6N5
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13
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Harter TS, Damsgaard C, Regan MD. Linking environmental salinity to respiratory phenotypes and metabolic rate in fishes: a data mining and modelling approach. J Exp Biol 2022; 225:274262. [PMID: 35258603 DOI: 10.1242/jeb.243421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The gill is the primary site of ionoregulation and gas exchange in adult teleost fishes. However, those characteristics that benefit diffusive gas exchange (large, thin gills) may also enhance the passive equilibration of ions and water that threaten osmotic homeostasis. Our literature review revealed that gill surface area and thickness were similar in freshwater (FW) and seawater (SW) species; however, the diffusive oxygen (O2) conductance (Gd) of the gill was lower in FW species. While a lower Gd may reduce ion losses, it also limits O2 uptake capacity and possibly aerobic performance in situations of high O2 demand (e.g. exercise) or low O2 availability (e.g. environmental hypoxia). We also found that FW fishes had significantly higher haemoglobin (Hb)-O2 binding affinities than SW species, which will increase the O2 diffusion gradient across the gills. Therefore, we hypothesized that the higher Hb-O2 affinity of FW fishes compensates, in part, for their lower Gd. Using a combined literature review and modelling approach, our results show that a higher Hb-O2 affinity in FW fishes increases the flux of O2 across their low-Gd gills. In addition, FW and SW teleosts can achieve similar maximal rates of O2 consumption (ṀO2,max) and hypoxia tolerance (Pcrit) through different combinations of Hb-O2 affinity and Gd. Our combined data identified novel patterns in gill and Hb characteristics between FW and SW fishes and our modelling approach provides mechanistic insight into the relationship between aerobic performance and species distribution ranges, generating novel hypotheses at the intersection of cardiorespiratory and ionoregulatory fish physiology.
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Affiliation(s)
- Till S Harter
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Christian Damsgaard
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
| | - Matthew D Regan
- Département de sciences biologiques, Université de Montréal, Montreal, QC, Canada, H3T 1J4
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14
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Damsgaard C, Country MW. The Opto-Respiratory Compromise: Balancing Oxygen Supply and Light Transmittance in the Retina. Physiology (Bethesda) 2022; 37:101-113. [PMID: 34843655 PMCID: PMC9159541 DOI: 10.1152/physiol.00027.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The light-absorbing retina has an exceptionally high oxygen demand, which imposes two conflicting needs: high rates of blood perfusion and an unobstructed light path devoid of blood vessels. This review discusses mechanisms and physiological trade-offs underlying retinal oxygen supply in vertebrates and examines how these physiological systems supported the evolution of vision.
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Affiliation(s)
- Christian Damsgaard
- 1Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark,2Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Michael W. Country
- 3Retinal Neurophysiology Section, National Eye Institute,
National Institutes of Health, Bethesda, Maryland
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15
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Joyce W, Wang T. Regulation of heart rate in vertebrates during hypoxia: A comparative overview. Acta Physiol (Oxf) 2022; 234:e13779. [PMID: 34995393 DOI: 10.1111/apha.13779] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/12/2021] [Accepted: 01/01/2022] [Indexed: 12/18/2022]
Abstract
Acute exposure to low oxygen (hypoxia) places conflicting demands on the heart. Whilst an increase in heart rate (tachycardia) may compensate systemic oxygen delivery as arterial oxygenation falls, the heart itself is an energetically expensive organ that may benefit from slowing (bradycardia) to reduce work when oxygen is limited. Both strategies are apparent in vertebrates, with tetrapods (mammals, birds, reptiles, and amphibians) classically exhibiting hypoxic tachycardia and fishes displaying characteristic hypoxic bradycardia. With a richer understanding of the ontogeny and evolution of the responses, however, we see similarities in the underlying mechanisms between vertebrate groups. For example, in adult mammals, primary bradycardia results from the hypoxic stimulation of carotid body chemoreceptors that are overwhelmed by mechano-sensory feedback from the lung associated with hyperpnoea. Fish-like bradycardia prevails in the mammalian foetus (which, at this stage, is incapable of pulmonary ventilation), and in fish and foetus alike, the bradycardia ensues despite an elevation of circulating catecholamines. In both cases, the reduced heart rate may primarily serve to protect the heart. Thus, the comparative perspective offers fundamental insight into how and why different vertebrates regulate heart rate in different ways during periods of hypoxia.
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Affiliation(s)
- William Joyce
- Department of Biology—Zoophysiology Aarhus University Aarhus C Denmark
| | - Tobias Wang
- Department of Biology—Zoophysiology Aarhus University Aarhus C Denmark
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16
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Comparative Transcriptomic Analysis of Regenerated Skins Provides Insights into Cutaneous Air-Breathing Formation in Fish. BIOLOGY 2021; 10:biology10121294. [PMID: 34943209 PMCID: PMC8698756 DOI: 10.3390/biology10121294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022]
Abstract
Cutaneous air-breathing is one of the air-breathing patterns in bimodal respiration fishes, while little is known about its underlying formation mechanisms. Here, we first investigated the skin regeneration of loach (Misgurnus anguillicaudatus, a cutaneous air-breathing fish) and yellow catfish (Pelteobagrus fulvidraco, a water-breathing fish) through morphological and histological observations. Then, the original skins (OS: MOS, POS) and regenerated skins (RS: MRS, PRS) when their capillaries were the most abundant (the structural foundation of air-breathing in fish) during healing, of the two fish species were collected for high-throughput RNA-seq. A total of 56,054 unigenes and 53,731 unigenes were assembled in loach and yellow catfish, respectively. A total of 640 (460 up- and 180 down-regulated) and 4446 (2340 up- and 2106 down-regulated) differentially expressed genes (DEGs) were respectively observed in RS/OS of loach and yellow catfish. Subsequently, the two DEG datasets were clustered in GO, KOG and KEGG databases, and further analyzed by comparison and screening. Consequently, tens of genes and thirteen key pathways were targeted, indicating that these genes and pathways had strong ties to cutaneous skin air-breathing in loach. This study provides new insights into the formation mechanism of cutaneous air-breathing and also offers a substantial contribution to the gene expression profiles of skin regeneration in fish.
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17
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Huang S, Yang L, Zhang L, Sun B, Gao J, Chen Z, Zhong L, Cao X. Endogenic upregulations of HIF/VEGF signaling pathway genes promote air breathing organ angiogenesis in bimodal respiration fish. Funct Integr Genomics 2021; 22:65-76. [PMID: 34839401 DOI: 10.1007/s10142-021-00822-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 11/20/2021] [Accepted: 11/22/2021] [Indexed: 11/28/2022]
Abstract
Air-breathing has evolved independently serval times with a variety of air-breathing organs (ABOs) in fish. The physiology of the air-breathing in bimodal respiration fish has been well understood, while studies on molecular mechanisms of the character are very limited. In the present study, we first determined the gill indexes of 110 fish species including 25 and 85 kinds of bimodal respiration fishes and non-air-breathing fishes, respectively. Then combined with histological observations of gills and ABOs/non-ABOs in three bimodal respiration fishes and two non-air breathing fishes, we found that the bimodal respiration fish was always of a degeneration gill and a well-vascularized ABO. Meanwhile, a comparative transcriptome analysis of posterior intestines, namely a well vascularized ABO in Misgurnus anguillicaudatus and a non-ABO in Leptobotia elongata, was performed to expound molecular variations of the air-breathing character. A total of 5,003 orthologous genes were identified. Among them, 1,189 orthologous genes were differentially expressed, which were enriched in 14 KEGG pathways. More specially, the expressions of hemoglobin genes and various HIF/VEGF signaling pathway genes were obviously upregulated in the ABO of M. anguillicaudatus. Moreover, we found that HIF-1α, VEGFAa, and MAP2K1 were co-expressed dramatically higher in ABOs of bimodal respiration fishes than those of non-ABOs of non-air-breathing fishes. These results indicated that the HIF/VEGF pathway played an important role in ABO angiogenesis/formation to promote fish to do aerial respiration. This study will contribute to our understanding of molecular mechanisms of air-breathing in fish.
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Affiliation(s)
- Songqian Huang
- College of Fisheries, Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, No.1 Shizishan Stress, Hongshan District, Wuhan, 430070, Hubei Province, China.,Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Bunkyo, Tokyo, 113-8657, Japan
| | - Lijuan Yang
- College of Fisheries, Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, No.1 Shizishan Stress, Hongshan District, Wuhan, 430070, Hubei Province, China
| | - Li Zhang
- College of Marxism, Shanghai University of Finance and Economics, Shanghai, 200433, China
| | - Bing Sun
- College of Fisheries, Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, No.1 Shizishan Stress, Hongshan District, Wuhan, 430070, Hubei Province, China
| | - Jian Gao
- College of Fisheries, Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, No.1 Shizishan Stress, Hongshan District, Wuhan, 430070, Hubei Province, China
| | - Zijian Chen
- College of Fisheries, Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, No.1 Shizishan Stress, Hongshan District, Wuhan, 430070, Hubei Province, China.,National Demonstration Center for Experimental Aquaculture Education, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lei Zhong
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, NO.173 Baishazhou Avenue, Hongshan District, Wuhan, 430207, Hubei Province, China.
| | - Xiaojuan Cao
- College of Fisheries, Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, Huazhong Agricultural University, No.1 Shizishan Stress, Hongshan District, Wuhan, 430070, Hubei Province, China.
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18
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Pelster B. Using the swimbladder as a respiratory organ and/or a buoyancy structure-Benefits and consequences. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2021; 335:831-842. [PMID: 33830682 DOI: 10.1002/jez.2460] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/16/2021] [Accepted: 03/22/2021] [Indexed: 11/07/2022]
Abstract
A swimbladder is a special organ present in several orders of Actinopterygians. As a gas-filled cavity it contributes to a reduction in overall density, but on descend from the water surface its contribution as a buoyancy device is very limited because the swimbladder is compressed by increasing hydrostatic pressure. It serves, however, as a very efficient organ for aerial gas exchange. To avoid the loss of oxygen to hypoxic water at the gills many air-breathing fish show a reduced gill surface area. This, in turn, also reduces surface area available for other functions, so that breathing air is connected to a number of physiological adjustments with respect to ion homeostasis, acid-base regulation and nitrogen excretion. Using the swimbladder as a buoyancy structure resulted in the loss of its function as an air-breathing organ and required the development of a gas secreting mechanism. This was achieved via the Root effect and a countercurrent arrangement of the blood supply to the swimbladder. In addition, a detachable air space with separated blood supply was necessary to allow the resorption of gas from the swimbladder. Gas secretion as well as gas resorption are slow phenomena, so that rapid changes in depth cannot instantaneously be compensated by appropriate volume changes. As gas-filled cavities the respiratory swimbladder and the buoyancy device require surfactant. Due to high oxygen partial pressures inside the bladder air-exposed tissues need an effective reactive oxygen species defense system, which is particularly important for a swimbladder at depth.
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Affiliation(s)
- Bernd Pelster
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences, University Innsbruck, Innsbruck, Austria
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19
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Andersen NCM, Fago A, Damsgaard C. Evolution of hemoglobin function in tropical air-breathing catfishes. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2021; 335:814-819. [PMID: 34254462 DOI: 10.1002/jez.2504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 11/08/2022]
Abstract
The evolution of hemoglobin function in the transition from water- to air-breathing has been highly debated but remains unresolved. Here, we characterized the hemoglobin function in five closely related water- and air-breathing catfishes. We identify distinct directions of hemoglobin evolution in the clades that evolved air-breathing, and we show strong selection on hemoglobin function within the catfishes. These findings show that the lack of a general direction in hemoglobin function in the transition from water- to air-breathing may have resulted from divergent selection on hemoglobin function in independent clades of air-breathing fishes.
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Affiliation(s)
| | - Angela Fago
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Christian Damsgaard
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus C, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, Aarhus C, Denmark
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20
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Martínez-Bautista G, Martínez-Burguete T, Peña-Marín ES, Jiménez-Martínez LD, Martínez-García R, Camarillo-Coop S, Burggren WW, Álvarez-González CA. Hypoxia- and hyperoxia-related gene expression dynamics during developmental critical windows of the tropical gar Atractosteus tropicus. Comp Biochem Physiol A Mol Integr Physiol 2021; 263:111093. [PMID: 34626804 DOI: 10.1016/j.cbpa.2021.111093] [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: 04/23/2021] [Revised: 08/21/2021] [Accepted: 09/29/2021] [Indexed: 12/20/2022]
Abstract
Aquatic hypoxia is both a naturally-occurring and anthropogenically-generated event. Fish species have evolved different adaptations to cope with hypoxic environments, including gill modifications and air breathing. However, little is known about the molecular mechanisms involved in the respiration of embryonic and larval fishes during critical windows of development. We assessed expression of the genes hif-1α, fih-1, nhe1, epo, gr and il8 using the developing tropical gar as a piscine model during three developmental periods (fertilization to hatch, 1 to 6 days post hatch (dph) and 7 to 12 dph) when exposed to normoxia (~7.43 mg/L DO), hypoxia (~2.5 mg/L DO) or hyperoxia (~9.15 mg/L DO). All genes had higher expression when fish were exposed to either hypoxia or hyperoxia during the first two developmental periods. However, fish continuously exposed to hypoxia had increased expression of the six genes by hatching and 6 dph, and by 12 dph only hif-1α still had increased expression. The middle developmental period was the most hypoxia-sensitive, coinciding with several changes in physiology and morphology. The oldest larvae were the most resilient to gene expression change, with little variation in expression of the six genes compared. This study is the first to relate the molecular response of an air-breathing fish to oxygen availability to developmental critical windows and contributes to our understanding of some molecular responses of developing fish to changes in oxygen availability.
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Affiliation(s)
- Gil Martínez-Bautista
- Laboratorio de Acuacultura Tropical, División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico; Developmental Physiology Laboratory, Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States.
| | - Talhia Martínez-Burguete
- Laboratorio de Acuacultura Tropical, División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Emyr Saul Peña-Marín
- Laboratorio de Acuacultura Tropical, División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Luis Daniel Jiménez-Martínez
- División Académica Multidisciplinaria de Jalpa de Méndez, Universidad Juárez Autónoma de Tabasco, Jalpa de Méndez, Tabasco, Mexico
| | - Rafael Martínez-García
- Laboratorio de Acuacultura Tropical, División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Susana Camarillo-Coop
- Laboratorio de Acuacultura Tropical, División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Warren W Burggren
- Developmental Physiology Laboratory, Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Carlos Alfonso Álvarez-González
- Laboratorio de Acuacultura Tropical, División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico.
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21
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Affiliation(s)
- Vera A. Kulow
- Charité – Universitätsmedizin Berlincorporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinMedizinische Klinik m.S. Nephrologie und Internistische Intensivmedizin Berlin Germany
| | - Michael Fähling
- Charité – Universitätsmedizin Berlincorporate member of Freie Universität Berlin and Humboldt‐Universität zu BerlinInstitut für Vegetative Physiologie Berlin Germany
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22
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Turko AJ, Rossi GS, Wright PA. More than Breathing Air: Evolutionary Drivers and Physiological Implications of an Amphibious Lifestyle in Fishes. Physiology (Bethesda) 2021; 36:307-314. [PMID: 34431416 DOI: 10.1152/physiol.00012.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Amphibious and aquatic air-breathing fishes both exchange respiratory gasses with the atmosphere, but these fishes differ in physiology, ecology, and possibly evolutionary origins. We introduce a scoring system to characterize interspecific variation in amphibiousness and use this system to highlight important unanswered questions about the evolutionary physiology of amphibious fishes.
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Affiliation(s)
- Andy J Turko
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Giulia S Rossi
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
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23
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Rossi GS, Wright PA. Does leaving water make fish smarter? Terrestrial exposure and exercise improve spatial learning in an amphibious fish. Proc Biol Sci 2021; 288:20210603. [PMID: 34130503 DOI: 10.1098/rspb.2021.0603] [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: 01/15/2023] Open
Abstract
Amphibious fishes transition between aquatic and terrestrial habitats, and must therefore learn to navigate two dramatically different environments. We used the amphibious killifish Kryptolebias marmoratus to test the hypothesis that the spatial learning ability of amphibious fishes would be altered by exposure to terrestrial environments because of neural plasticity in the brain region linked to spatial cognition (dorsolateral pallium). We subjected fish to eight weeks of fluctuating air-water conditions or terrestrial exercise before assessing spatial learning using a bifurcating T-maze, and neurogenesis in the dorsolateral pallium by immunostaining for proliferating cell nuclear antigen. In support of our hypothesis, we found that air-water fluctuations and terrestrial exercise improved some markers of spatial learning. Moreover, air-water and exercised fish had 39% and 46% more proliferating cells in their dorsolateral pallium relative to control fish, respectively. Overall, our findings suggest that fish with more terrestrial tendencies may have a cognitive advantage over those that remain in water, which ultimately may influence their fitness in both aquatic and terrestrial settings. More broadly, understanding the factors that promote neural and behavioural plasticity in extant amphibious fishes may provide insights into how ancestral fishes successfully colonized novel terrestrial environments before giving rise to land-dwelling tetrapods.
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Affiliation(s)
- Giulia S Rossi
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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24
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Histological Study of Suprabranchial Chamber Membranes in Anabantoidei and Clariidae Fishes. Animals (Basel) 2021; 11:ani11041158. [PMID: 33920739 PMCID: PMC8073562 DOI: 10.3390/ani11041158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 01/18/2023] Open
Abstract
Simple Summary Air-breathing fish constitute a broad evolutionary group of fish, which are generally characterized by distinctive phenotypical plasticity. These fishes usually inhabit waters where oxygen deficiency occurs periodically, which is why they have developed a variety of accessory respiratory organs (AROs) that may be used in an obligatory or a facultative manner. Knowledge of the structure of these organs is important for both the breeding and the conservation of these fish species. The aim of this study was to conduct a comparative histological analysis of two types of AROs found in the Anabantoidei suborder and the Clariidae family, both of which are freshwater fish taxa of high ecological and commercial importance. Abstract Accessory respiratory organs (AROs) are a group of anatomical structures found in fish, which support the gills and skin in the process of oxygen uptake. AROs are found in many fish taxa and differ significantly, but in the suborder Anabantoidei, which has a labyrinth organ (LO), and the family Clariidae, which has a dendritic organ (DO), these structures are found in the suprabranchial cavity (SBC). In this study, the SBC walls, AROs, and gills were studied in anabantoid (Betta splendens, Ctenopoma acutirostre, Helostoma temminckii) and clariid (Clarias angolensis, Clarias batrachus) fishes. The histological structure of the investigated organs was partially similar, especially in relation to their connective tissue core; however, there were noticeable differences in the epithelial layer. There were no significant species-specific differences in the structure of the AROs within the two taxa, but the SBC walls had diversified structures, depending on the observed location. The observed differences between species suggest that the remarkable physiological and morphological plasticity of the five investigated species can be associated with structural variety within their AROs. Furthermore, based on the observed histology of the SBC walls, it is reasonable to conclude that this structure participates in the process of gas exchange, not only in clariid fish but also in anabantoids.
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25
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Morgan R, Tunnah L, Tuong DD, Hjelmstedt P, Nhu PN, Stiller KT, Phuong NT, Huong DTT, Bayley M, Wang T, Milsom WK. Striped catfish (Pangasianodon hypophthalmus) use air-breathing and aquatic surface respiration when exposed to severe aquatic hypercarbia. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:820-830. [PMID: 33773086 DOI: 10.1002/jez.2453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 01/26/2021] [Indexed: 11/06/2022]
Abstract
We investigated the extent to which the facultative air-breathing fish, the striped catfish (Pangasianodon hypophthalmus), uses air-breathing to cope with aquatic hypercarbia, and how air-breathing is influenced by the experimental exposure protocol and level of hypercarbia. We exposed individuals to severe aquatic hypercarbia (up to Pw CO2 = 81 mmHg) using step-wise and progressive exposure protocols while measuring gill ventilation rate, heart rate, mean arterial blood pressure, and air-breathing frequency, as well as arterial blood pH and PCO2 . We confirm that P. hypophthalmus is tolerant of hypercarbia. Under both protocols gill ventilation rate, heart rate, and mean arterial blood pressure were maintained near control levels even at very high CO2 levels. We observed a marked amount of individual variation in the PwCO2 at which air-breathing was elicited, with some individuals not responding at all. The experimental protocol also influenced the onset of air-breathing. Air-breathing began at lower Pw CO2 in the step-wise protocol (23 ± 4.1 mmHg) compared with the progressive protocol (46 ± 7.8 mmHg). Air-breathing was often followed by aquatic surface respiration, at higher PCO2 (71 ± 5.2 mmHg) levels. On average, the blood PCO2 was approximately 43% lower (46 ± 2.5 mmHg) than water Pw CO2 (~81 mmHg) at our highest tested CO2 level. While this suggests that aerial CO2 elimination is an effective, and perhaps critical, respiratory strategy used by P. hypophthalmus to cope with severe hypercarbia, this observation may also be explained by a long lag time required for equilibration.
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Affiliation(s)
- Rachael Morgan
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Louise Tunnah
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Dang D Tuong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Per Hjelmstedt
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, Skara, Sweden
| | - Pham N Nhu
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Kevin T Stiller
- Production Biology - The Norwegian Institute of Food, Fisheries and Aquaculture Research, Nofima AS, Sjølseng, Sunndalsøra, Norway
| | - Nguyen Thanh Phuong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Do Thi Thanh Huong
- Department of Aquatic Nutrition and Products Processing, College of Aquaculture and Fisheries, Can Tho University, Can Tho, Vietnam
| | - Mark Bayley
- Department of Bioscience, Zoophysiology, Aarhus, Denmark
| | - Tobias Wang
- Department of Bioscience, Zoophysiology, Aarhus, Denmark
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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26
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Dong YW, Blanchard TS, Noll A, Vasquez P, Schmitz J, Kelly SP, Wright PA, Whitehead A. Genomic and physiological mechanisms underlying skin plasticity during water to air transition in an amphibious fish. J Exp Biol 2021; 224:jeb235515. [PMID: 33328287 PMCID: PMC7860121 DOI: 10.1242/jeb.235515] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022]
Abstract
The terrestrial radiation of vertebrates required changes in skin that resolved the dual demands of maintaining a mechanical and physiological barrier while also facilitating ion and gas transport. Using the amphibious killifish Kryptolebias marmoratus, we found that transcriptional regulation of skin morphogenesis was quickly activated upon air exposure (1 h). Rapid regulation of cell-cell adhesion complexes and pathways that regulate stratum corneum formation was consistent with barrier function and mechanical reinforcement. Unique blood vessel architecture and regulation of angiogenesis likely supported cutaneous respiration. Differences in ionoregulatory transcripts and ionocyte morphology were correlated with differences in salinity acclimation and resilience to air exposure. Evolutionary analyses reinforced the adaptive importance of these mechanisms. We conclude that rapid plasticity of barrier, respiratory and ionoregulatory functions in skin evolved to support the amphibious lifestyle of K. marmoratus; similar processes may have facilitated the terrestrial radiation of other contemporary and ancient fishes.
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Affiliation(s)
- Yun-Wei Dong
- The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, People's Republic of China
| | - Tessa S Blanchard
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Angela Noll
- Primate Genetics Laboratory, German Primate Center (DPZ), Leibniz Institute for Primate Research, 37077 Göttingen, Germany
| | - Picasso Vasquez
- Department of Environmental Toxicology, University of California Davis, Davis, CA 95616, USA
| | - Juergen Schmitz
- Institute of Experimental Pathology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
| | - Scott P Kelly
- Department of Biology, York University, Toronto, ON, Canada, M3J 1P3
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Andrew Whitehead
- Department of Environmental Toxicology, Center for Population Biology, Coastal and Marine Sciences Institute, University of California Davis, Davis, CA 95616, USA
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27
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Damsgaard C, Lauridsen H, Harter TS, Kwan GT, Thomsen JS, Funder AM, Supuran CT, Tresguerres M, Matthews PG, Brauner CJ. A novel acidification mechanism for greatly enhanced oxygen supply to the fish retina. eLife 2020; 9:58995. [PMID: 32840208 PMCID: PMC7447425 DOI: 10.7554/elife.58995] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/29/2020] [Indexed: 11/19/2022] Open
Abstract
Previously, we showed that the evolution of high acuity vision in fishes was directly associated with their unique pH-sensitive hemoglobins that allow O2 to be delivered to the retina at PO2s more than ten-fold that of arterial blood (Damsgaard et al., 2019). Here, we show strong evidence that vacuolar-type H+-ATPase and plasma-accessible carbonic anhydrase in the vascular structure supplying the retina act together to acidify the red blood cell leading to O2 secretion. In vivo data indicate that this pathway primarily affects the oxygenation of the inner retina involved in signal processing and transduction, and that the evolution of this pathway was tightly associated with the morphological expansion of the inner retina. We conclude that this mechanism for retinal oxygenation played a vital role in the adaptive evolution of vision in teleost fishes.
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Affiliation(s)
| | - Henrik Lauridsen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Till S Harter
- Scripps Institution of Oceanography, UC San Diego, La Jolla, United States
| | - Garfield T Kwan
- Scripps Institution of Oceanography, UC San Diego, La Jolla, United States
| | | | - Anette Md Funder
- Department of Forensic Medicine, Aarhus University, Aarhus, Denmark
| | - Claudiu T Supuran
- Università degli Studi di Firenze, Neurofarba Department, Sezione di Scienze Farmaceutiche, Florence, Italy
| | - Martin Tresguerres
- Scripps Institution of Oceanography, UC San Diego, La Jolla, United States
| | - Philip Gd Matthews
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, Canada
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28
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Gam LTH, Thanh Huong DT, Tuong DD, Phuong NT, Jensen FB, Wang T, Bayley M. Effects of temperature on acid-base regulation, gill ventilation and air breathing in the clown knifefish, Chitala ornata. J Exp Biol 2020; 223:jeb216481. [PMID: 32001546 DOI: 10.1242/jeb.216481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/23/2020] [Indexed: 11/20/2022]
Abstract
Chitala ornata is a facultative air-breathing fish, which at low temperatures shows an arterial PCO2 (PaCO2 ) level only slightly elevated above that of water breathers. By holding fish with in-dwelling catheters at temperatures from 25 to 36°C and measuring blood gasses, we show that this animal follows the ubiquitous poikilotherm pattern of reducing arterial pH with increasing temperature. Surprisingly, the temperature increase caused an elevation of PaCO2 from 5 to 12 mmHg while the plasma bicarbonate concentration remained constant at around 8 mmol l-1 The temperature increase also gave rise to a larger fractional increase in air breathing than in gill ventilation frequency. These findings suggest that air breathing, and hence the partitioning of gas exchange, is to some extent regulated by acid-base status in air-breathing fish and that these bimodal breathers will be increasingly likely to adopt respiratory pH control as temperature rises, providing an interesting avenue for future research.
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Affiliation(s)
- Le Thi Hong Gam
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Do Thi Thanh Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Dang Diem Tuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Nguyen Thanh Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho City, Vietnam
| | - Frank Bo Jensen
- Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
- Aarhus Institute of Advanced Studies, 8000 Aarhus C, Denmark
| | - Mark Bayley
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus, Denmark
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29
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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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30
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Damsgaard C, Lauridsen H, Funder AM, Thomsen JS, Desvignes T, Crossley DA, Møller PR, Huong DT, Phuong NT, Detrich HW, Brüel A, Wilkens H, Warrant E, Wang T, Nyengaard JR, Berenbrink M, Bayley M. Retinal oxygen supply shaped the functional evolution of the vertebrate eye. eLife 2019; 8:52153. [PMID: 31820735 PMCID: PMC6904217 DOI: 10.7554/elife.52153] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/19/2019] [Indexed: 11/13/2022] Open
Abstract
The retina has a very high energy demand but lacks an internal blood supply in most vertebrates. Here we explore the hypothesis that oxygen diffusion limited the evolution of retinal morphology by reconstructing the evolution of retinal thickness and the various mechanisms for retinal oxygen supply, including capillarization and acid-induced haemoglobin oxygen unloading. We show that a common ancestor of bony fishes likely had a thin retina without additional retinal oxygen supply mechanisms and that three different types of retinal capillaries were gained and lost independently multiple times during the radiation of vertebrates, and that these were invariably associated with parallel changes in retinal thickness. Since retinal thickness confers multiple advantages to vision, we propose that insufficient retinal oxygen supply constrained the functional evolution of the eye in early vertebrates, and that recurrent origins of additional retinal oxygen supply mechanisms facilitated the phenotypic evolution of improved functional eye morphology.
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Affiliation(s)
- Christian Damsgaard
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.,Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Henrik Lauridsen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, United States
| | - Anette Md Funder
- Department of Forensic Medicine, Aarhus University, Aarhus, Denmark
| | | | - Thomas Desvignes
- Institute of Neuroscience, University of Oregon, Eugene, United States
| | - Dane A Crossley
- Department of Biological Sciences, University of North Texas, Denton, United States
| | - Peter R Møller
- Section for Evolutionary Genomics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Do Tt Huong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Viet Nam
| | - Nguyen T Phuong
- College of Aquaculture and Fisheries, Can Tho University, Can Tho, Viet Nam
| | - H William Detrich
- Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, Nahant, United States
| | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Horst Wilkens
- Zoological Institute and Zoological Museum, University of Hamburg, Hamburg, Germany
| | - Eric Warrant
- Department of Biology, Lund University, Lund, Sweden
| | - Tobias Wang
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Jens R Nyengaard
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Centre for Stochastic Geometry and Advanced Bioimaging, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Michael Berenbrink
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Mark Bayley
- Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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