James A. Raymond

Associate Research Professor
Ph.D., University of California, San Diego, 1976
702-895-3268
raymond@nevada.edu

Physiological and biochemical adaptations of polar organisms to their environment

Research interests

• Polar organisms have developed a variety of biochemical strategies for surviving at freezing temperatures. My previous work on fish antifreezes has expanded to investigations of antifreeze-like macromolecules that I have found to be present in a wide variety of polar marine and freshwater algae. They are not true antifreezes but appear to have other functions associated with protecting cells in the frozen state. My objectives are to determine the distributions of these molecules among different species and habitats, their molecular structures, and what roles they play.

• Another research interest is the biochemistry and physiology of an unusual group of arctic fishes that use high concentrations of osmolytes in addition to peptide antifreezes to enhance their freezing resistance. Such osmolytes include glycerol, trimethylamine oxide (TMAO) and urea. In one species, these osmolytes make the fish nearly isosmotic in full-strength seawater. Current interests include the environmental triggers of the production of the osmolytes, their metabolic sources and fate, and the cellular mechanisms responsible for the uneven distribution of TMAO among the different tissues of these fishes.

Recent publications

Raymond, J.A. 2000. Distribution and partial characterization of an ice-active molecule associated with sea ice diatoms. Polar Biology  23 : 721-729

Raymond, J.A. and C. H. Fritsen. 2000. Ice-active substances associated with Antarctic freshwater and terrestrial photosynthetic organisms. Antarctic Science 12:418-424.

Raymond, J.A. and A. Hassel. 2000. Some characteristics of freezing avoidance in two osmerids, rainbow smelt and capelin. J. Fish Biology 57A: 1-7.

Raymond, J.A. and A.L. DeVries. 1998. Elevated concentrations and synthetic pathways of trimethylamine oxide and urea in some teleost fishes of McMurdo Sound, Antarctica. Fish Physiol. Biochem. 18:387-398.

Raymond, J.A. 1998. Trimethylamine oxide and urea synthesis in rainbow trout and some other northern fishes. Physiol. Zool. 71: 515-523.

Driedzic, W.R., J.L. West, D.H. Sephton and J.A. Raymond. 1998. Enzyme activity levels associated with    the production of glycerol as an antifreeze in liver of rainbow smelt (Osmerus mordax). Fish Physiol. Biochem. 18:125-134.

Raymond, J.A. and W. R. Driedzic. 1997. Amino acids are a source of glycerol in cold-acclimated rainbow smelt. Comp. Biochem. Physiol. 118B: 387-393.

Raymond, J.A. 1996 Responses of marine fishes to freezing temperatures: A new look at colligative mechanisms. In: Advances in Cell and Molecular Biology, Vol. on Thermobiology, ed. by J.S. Willis. JAI Press.

Raymond, J.A. 1995. Glycerol Synthesis in the rainbow smelt Osmerus mordax. J. Exp. Biol. 198: 2569-2573.

Raymond, J.A. C.W. Sullivan and A. L. DeVries. 1994. Release of an ice-active substance by antarctic sea ice diatoms. Polar Biology 14: 71-75.