Study of freeze-avoidance in the ooplasm of an Antarctic fish, Gymnodraco acuticeps, using NMR spectroscopy

CHED 921

Troy Link, bluedevils21@hotmail.com1, Marina Marjanovic, mmarjanovic@eiu.edu2, and Barbara A Lawrence, balawrence@eiu.edu1. (1) Department of Chemistry, Eastern Illinois University, 600 Lincoln Ave., Charleston, IL 61920, (2) Department of Biological Sciences, Eastern Illinois University, 600 Lincoln Ave., Charleston, 61920
The ooplasm of fertilized eggs of the Antarctic dragon fish, G. acuticeps have a freezing point of -2.3?C. These eggs are protected from freezing by the presence of antifreeze glycoproteins (AFGPs) that serve to decrease the freezing point and by the colligative properties of univalent ions that decrease the freezing point still further. H-1 and P-31 NMR spectroscopy were used in this study to identity and measure the concentration of additional osmolytes. H-1 spectra revealed 45-55mM trimethylamine oxide (TMAO) and a variable amount of urea, both previously identified osmolytes in fish. P-31 spectra combined with lipid extraction revealed a mixture of a phosphodiester and two phospholipids. The phosphodiester, with a concentration of 5mM, would act as an osmolyte; however, the phospholipids are less likely to lower freezing point of the eggs due to the formation of bilayer congregates, as indicated by broad lines in the NMR spectra.

 

Undergraduate Research Poster Session: Biochemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Chemical Education

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007