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Skeletal muscle remodeling in amphibious fishes out of water

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dc.contributor.advisor Wright, Patricia Rossi, Giulia 2021-06-04T21:35:56Z 2021-06 2021-05-27 2018-06
dc.description.abstract One of the most extreme ecological transitions has been the colonization of land by fishes. Moving between aquatic and terrestrial environments poses critical challenges for a number of processes, including locomotion. The focus of my PhD was to investigate how the skeletal muscle of fishes remodels in response to various forms of air-exposure (e.g., constant, fluctuating) and determine the functional implications of this plasticity. I used an amphibious killifish (Kryptolebias marmoratus) to first test the hypothesis that skeletal muscle remodelling in response to constant (28 d) air-exposure is driven by the increased oxygen availability in air. Indeed, oxygen was a driver for muscle remodeling on land, as both air-exposure and hyperoxia increased (>25%) the size of red muscle fibers in K. marmoratus. Since K. marmoratus can survive for weeks on land without food, I then questioned how fish were able to maintain their muscle integrity during prolonged periods of air-exposure (21 d). I tested the hypothesis that amphibious fishes that remain on land for weeks at a time use metabolic depression as a strategy to preserve muscle integrity. My results demonstrated that metabolic depression is important for slowing the use of endogenous energy stores by fish on land, including muscle protein. I also found that K. marmoratus seek hypoxic microhabitats during prolonged air-exposure that accentuate metabolic depression. Given the highly plastic nature of K. marmoratus muscle, I then tested the hypothesis that the scope for muscle plasticity is modulated by environmental conditions during early development. I found that fluctuating water-air conditions during development attenuated the scope for muscle plasticity in later life. Finally, I was interested to understand the broader role of muscle and terrestrial locomotion in facilitating land invasions by fishes. I tested the hypothesis that terrestrial exercise would improve spatial cognition in amphibious fishes, and enhance neurogenesis in the brain region linked to spatial cognition. I found that terrestrial excursions enhanced cognition in K. marmoratus, as both terrestrial exercise and air-exposure improved spatial learning abilities. Overall, my thesis integrates behavioural, morphological, and physiological perspectives to provide new insights into how amphibious fishes successfully colonize and exploit terrestrial habitats. en_US
dc.description.sponsorship Funding was provided by the Natural Sciences and Engineering Research Council of Canada. en_US
dc.language.iso en en_US
dc.publisher University of Guelph en_US
dc.subject skeletal muscle en_US
dc.subject amphibious fish en_US
dc.subject phenotypic plasticity en_US
dc.subject Kryptolebias marmoratus en_US
dc.subject locomotion en_US
dc.subject physiology en_US
dc.subject behaviour en_US
dc.subject metabolism en_US
dc.title Skeletal muscle remodeling in amphibious fishes out of water en_US
dc.type Thesis en_US Integrative Biology en_US Doctor of Philosophy en_US Department of Integrative Biology en_US
dc.description.embargo 2021-12-31
dc.rights.license All items in the Atrium are protected by copyright with all rights reserved unless otherwise indicated.
dcterms.relation Rossi GS, Turko AJ, Wright PA (2018) Oxygen drives skeletal muscle remodeling in an amphibious fish out of water. Journal of Experimental Biology. 221, jeb180257. en_US University of Guelph en_US

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