2002-2003 Science Planning Summary

Biology & Medicine

Dr. Polly Penhale
Program Manager

BO-036-L/P

NSF/OPP 01-25890
Station: RV Laurence M. Gould and Palmer Station
RPSC POC: Rob Edwards
Research Site(s): Dallman Bay, Arthur Harbor, Anvers Island

Cold body temperature as an evolutionary shaping force in the physiology of antarctic fishes
Dr. Bruce D. Sidell
The University of Maine
School of Marine Sciences
BSidell@maine.edu

Deploying Team Members: Jamie Hendrickson . Timothy S Moerland . Bruce D Sidell
Research Objectives: Notothenioid fishes have been evolving for 10 to 14 million years at a nearly constant body temperature of ~0ºC. Many unusual characteristics of these fishes are adaptations to life at cold body temperatures or physiological or biochemical features permitted by life at cold body temperatures but otherwise deleterious. This project's three major objectives will entail a combination of shipboard collection of fishes and experimentation at Palmer Station, with more extensive and sophisticated laboratory analyses on samples in the United States.

Researchers will identify the amino acid substitutions in the fatty acid-binding pocket of fatty acyl coenzyme A synthetase (FACS) from antarctic fishes. Fatty acids are a major source of energy in these fishes, and FACS is essential to their metabolism. Site-directed mutagenesis will be used to produce modified antarctic fish FACS in which specific amino acids have been mutated to those of consensus sequences from warmer-bodied vertebrate animals. These experiments may permit the researchers to determine the specific substitutions that explain both substrate specificity and preservation of catalytic rate of notothenioid FACS at cold temperatures.

The group will also produce a rigorous biochemical and biophysical characterization of an intracellular binding protein, parvalbumin, from antarctic fishes. Parvalbumin plays a pivotal role in facilitating the relaxation of fast-contracting muscles and is a likely site of strong selective pressure. Preliminary data strongly indicate that in antarctic fishes, the protein has been modified to function at cold temperatures. Full-length clones for antarctic fish parvalbumin(s) will be obtained. In combination with already available information, these data will yield insight into their functioning at very cold body temperatures.

Finally, the group will conduct a broad survey of the pattern of cardiac myoglobin (Mb) expression in the Notothenioidei. Previous work has indicated a variable pattern of presence or absence of Mb in the hearts of icefishes, probably due to the unusually low niche competition in the Southern Ocean. It is likely that similar loss of cardiac Mb will be observed in other notothenioid taxa. Project team members will survey as many notothenioid species as possible and will use molecular biological techniques to determine the mechanism(s) responsible for loss of Mb expression.


Field Season Overview:
Aboard the R/V Laurence M. Gould in the Antarctic Peninsula, researchers will collect fish using mobile trawls, buoyed and anchored fish pots and longlines. The primary collecting areas include Dallmann Bay, the south shore of Low Island and the southeast shore of Livingston Island. The aquarium room on board the vessel will maintain live specimens during transport to Palmer Station for subsequent experiments. Fish will also be collected in the local Palmer area using hook-and-line and fish traps from Zodiac inflatable boats. At Palmer Station, experiments will be performed using both live fish and prepared tissues. Tissue samples will also be returned to the home institution for further analysis.