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Characterizing the Link between Biological Membranes and Thermal Physiology in Antarctic Notothenioid Fishes

Biederman, Amanda M.
http://orcid.org/0000-0003-3555-1104
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1561993742334324

Abstract Details

2019, Doctor of Philosophy (PhD), Ohio University, Biological Sciences (Arts and Sciences).
The Antarctic notothenioid fishes are among the most stenothermal animals on the planet and are likely to be vulnerable to the effects of global climate change. The physiological mechanisms that govern the thermal tolerance of Antarctic notothenioids are not fully understood. Membrane integrity and structure are highly sensitive to temperature and are critical to maintenance of cellular function. The two central hypotheses of this work are: (1) Variation in physical and biochemical membrane properties exists among notothenioids that display differences in thermal tolerance and thermal sensitivity of physiological processes; and (2) Membranes of Notothenia coriiceps undergo lipid remodeling in response to long-term thermal change in order to conserve membrane properties. Physical and biochemical properties of biological membranes from several tissues (cardiac ventricles and brain) were analyzed in several species of notothenioids in order to characterize variation in properties of biological membranes within this suborder of fishes. I also sought to determine whether notothenioids possess the capacity for acclimation to elevated temperature by determining the extent of compensation of membrane properties in several tissues (cardiac ventricles, brain, gill). Findings from this work provide novel insight into how notothenioids are likely to fare within a warmer climate. An interspecific comparative analysis was performed between notothenioids that exhibit variation in thermal tolerance (Chapters 2, 3). Membrane fluidity and composition were measured in several brain (synaptic, myelin, mitochondria) and cardiac (mitochondria) membranes from the red blooded (more thermotolerant) Notothenia coriiceps and the white-blooded Chaenocephalus aceratus. Synaptic membranes and cardiac mitochondria were more fluid in the icefish, compared to the red-blooded species. Hyperfluidization of membranes, particularly in the less thermotolerant species, C. aceratus, is consistent with the failure of the nervous and cardiovascular systems upon acute warming. Additionally, properties of membranes from N. coriiceps were analyzed following several weeks of acclimation to 0°C or 5ºC (Chapters 4, 5). In Chapter 4, fluidity was compared between thermal treatment groups in brain (synaptic membranes, myelin, mitochondria) and cardiac (mitochondria, microsomes) membranes. Biochemical analyses of membrane composition were performed on select membranes. Results suggest evidence of homeoviscous adaptation in the cardiac, but not brain, membranes. Both cardiac mitochondria and microsomes displayed reduced fluidity following acclimation to 5°C, indicating full thermal compensation when the membrane fluidity is compared at the animal’s respective acclimation temperature. In Chapter 5, fluidity, composition, and osmotic permeability were compared between thermal treatment groups in plasma membranes from gill epithelia. Results provide evidence for membrane remodeling, consistent with the observed preservation of membrane fluidity upon acclimation. Further, measurements of osmotic uptake in gill epithelia suggest membrane permeability is reduced during acclimation to 5°C, possibly to compensate for the effects of higher temperatures that would otherwise render the membrane more permeable. For cardiac and branchial membranes, differences in fluidity were achieved by modulation of membrane cholesterol contents and/or fatty acyl chain length. Taken together, these results provide evidence for thermal plasticity of membrane properties in the cardiac and branchial systems of this species. The lack of a homeoviscous response and membrane restructuring in the brain would appear to limit the capacity for thermal acclimation in N. coriiceps. In total, these data indicate that the nervous system is likely to be the most susceptible to failure with increased warming in the Southern Ocean.
Elizabeth L. Crockett, Ph.D. (Advisor)
Janet Duerr, Ph.D. (Committee Member)
Daewoo Lee, Ph.D. (Committee Member)
Sarah Wyatt, Ph.D. (Committee Member)
Theresa Grove, Ph.D. (Committee Member)
171 p.
Animal Sciences; Aquatic Sciences; Biology; Physiology
Antarctic fish; notothenioid; thermal tolerance; membranes; membrane fluidity; lipids; phospholipids; cholesterol; fatty acids

Recommended Citations

Citations

  • Biederman, A. M. (2019). Characterizing the Link between Biological Membranes and Thermal Physiology in Antarctic Notothenioid Fishes [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1561993742334324

    APA Style (7th edition)

  • Biederman, Amanda. Characterizing the Link between Biological Membranes and Thermal Physiology in Antarctic Notothenioid Fishes. 2019. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1561993742334324.

    MLA Style (8th edition)

  • Biederman, Amanda. "Characterizing the Link between Biological Membranes and Thermal Physiology in Antarctic Notothenioid Fishes." Doctoral dissertation, Ohio University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1561993742334324

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Ohio University and OhioLINK.