2002-2003 Science Planning Summary

Biology & Medicine

Dr. Polly Penhale
Program Manager

BO-006-O

NSF/OPP 01-30398
Station: McMurdo Station
RPSC POC: Rob Robbins
Research Site(s): Cinder Cones, Cape Evans, Cape Armitage, New Harbor, Crary Lab

Energetics of protein metabolism during development of Antarctic echinoderms
Dr. Donal T. Manahan
University of Southern California
Department of Biological Sciences
manahan@usc.edu

Deploying Team Members: David W Ginsburg . Allison J Green . Amanda L Haag . Donal T Manahan . Robert E Maxson . Douglas A Pace . Matt Winkler
Research Objectives: Larval forms are dominant in the life history strategies of invertebrates in marine environments. In Antarctica, energy budget calculations have shown that larval stages of echinoderms have the capacity to survive for years without food. This has led to the speculation that mechanisms of energy metabolism are more efficient in these larval forms and that this enhanced efficiency might be unique to life in extreme cold.

Embryos and larvae of an antarctic sea urchin have high rates of protein synthesis while maintaining low rates of metabolism. The cost of protein synthesis in this antarctic sea urchin is 1/25th that reported for other animals. This is the lowest cost (highest efficiency) for protein synthesis ever reported and has important implications for the physiology of animal growth and development in cold environments. This project will investigate this unique biochemical efficiency in detail.

This experimental plan has three major objectives:

• Test the generality of the low cost of protein synthesis in antarctic sea urchin larvae by measuring metabolism and protein synthesis during development of other antarctic echinoderm species

• Directly test the hypothesis that a high rate of protein synthesis with low metabolic cost means that growth efficiencies will be high in such organisms,

• Explain in specific molecular terms the unique high efficiency of protein synthesis in antarctic sea urchin embryos by studying each of the component processes of protein synthesis.

These measurements will be supplemented with measurements based on selected individual proteins. At the subcellular level, rates of ATP consumption during protein synthesis will be measured in cell-free translation systems of sea urchin embryos. The combination of these quantitative analyses will enable researchers to pinpoint those aspects of protein metabolism that result in such extremely high-energy efficiencies.

Understanding metabolic efficiency in polar organisms will help resolve questions about temperature compensation and adaptations to food limitation in polar regions. This approach emphasizes the cellular and subcellular levels of biological analysis in order to understand the relationship between development, growth, metabolic rate, and rates and costs of protein synthesis in these organisms. This project will test the hypothesis that there is a “new” biochemistry for protein synthesis in these organisms.


Field Season Overview:
Project team members will dive to perform experiments and collect benthic samples. Support contractor personnel will drill holes and transport huts to dive locations. Researchers will travel by tracked vehicle to diving locations at Cinder Cones, Cape Evans, and Cape Armitage, and by helicopter to sites around New Harbor. The aquarium, darkroom and freezers in the Crary Lab will be used for sample processing.