USAP-DC

Antarctic notothenioid fishes have evolved in the Southern Ocean for 10-14 MY under an unusual set of circumstances. Their characteristics include the complete absence of the circulating oxygen-binding protein, hemoglobin (Hb) within the Channichthyid (Icefish) family of notothenioids. Moreover, some species within the 16 members of this family have also lost the ability to express the oxygen-binding and storage protein, myoglobin (Mb) in cardiac muscle. Our previous work has determined that the loss of Hb and/or Mb is correlated with significant increases in densities of mitochondria within oxidative tissues, and extensive remodeling of these vital organelles. To date, nothing is known about how modifications in mitochondrial architecture of icefishes affect organelle function, or more importantly, how they affect organismal-level physiology. Most critical for Antarctic fishes is that mitochondrial characteristics have been linked to how well ectotherms can withstand increases in temperature.

This collaborative research project will address the hypothesis that the unusual mitochondrial architecture of Antarctic Channichthyids has led to changes in function that impact their ability to withstand elevations in temperature. Specifically, the research will (1) determine if the unusual mitochondrial architecture of icefishes affects function and contributes to organismal thermal sensitivity, (2) identify differences in organismal thermal tolerance between red- and white- blooded notothenioids, (3) identify molecular mechanisms regulating changes in mitochondrial structure in icefishes. The results may establish channichthyid icefishes as a sentinel taxon for signaling the impact of global warming on the Southern Ocean. Broad impacts of this project will be realized by participation of high school biology teachers in field work through cooperation with the ARMADA project at the University of Rhode Island, as well as graduate education.

Person	Role
Crockett, Elizabeth	Investigator
O'Brien, Kristin	Investigator

Antarctic Organisms and Ecosystems	Award # 1142720
Antarctic Organisms and Ecosystems	Award # 0741301

NSF-ANT07-41301_1
NSF-ANT11-42720

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Linkages among Mitochondrial Form, Function and Thermal Tolerance of Antarctic Notothenioid Fishes	None	exist

1. Keenan, K. A., Grove, T. J., Oldham, C. A., & O’Brien, K. M. (2017). Characterization of mitochondrial glycerol-3-phosphate acyltransferase in notothenioid fishes. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 204, 9–26. (doi:10.1016/j.cbpb.2016.11.001)
2. O’Brien, K. M., Mueller, I. A., Orczewska, J. I., Dullen, K. R., & Ortego, M. (2014). Hearts of some Antarctic fishes lack mitochondrial creatine kinase. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 178, 30–36. (doi:10.1016/j.cbpa.2014.08.003)