Environmental factors of the marine environment, such as temperature, osmotic conditions and hydrostatic pressure, directly affect the biochemical processes of ectothermic organisms. Rates of enzymic catalysis, protein-ligand interactions, and higher orders of protein structure (e.g., tertiary and quaternary structure) may be perturbed by these environmental variables. In order to evaluate the importance of such factors in shaping the evolutionary adaptations of deep-sea species and in influencing the ecology and distribution of species, work in my laboratory centers on the effects of temperature, osmolytes and hydrostatic pressure on enzyme structure and function and on integral membrane proteins.
In order to maintain cell volume under conditions of water stress organisms accumulate a variety of small organic osmolytes rather than inorganic salts which can disrupt macromolecular structure and function. These osmolytes may protect cells from other stresses as well. Current studies are focused on the possible roles of osmolytes in stabilizing macromolecules.
P.H. Yancey and J.F. Siebenaller (2015) Co-evolution of proteins and solutions: protein
adaptation versus cytoprotective micromolecules and
their roles in marine organisms. Journal of Experimental Biology 218: 1880-1896.
C.S. Gregg, J.D. Ales, S.M. Pomarico, E.W. Wischusen and J.F. Siebenaller (2013) Scientific teaching targeting faculty from diverse institutions. CBE-Life Sciences Education 12: 383-393.
M.K. Desmond and J.F. Siebenaller (2006) Non-additive counteraction of KCl-perturbation of lactate dehydrogenase by trimethylamine N-oxide. Protein and Peptide Letters 13: 555-557.
J.F. Siebenaller and D.J. Garrett (2005) Deep-sea pressures alter G protein function in marine teleost fishes. Recent Research Developments in Experimental & Theoretical Biology 1:1-18.
J.F. Siebenaller (2003) Pressure effects on the GTPase activity of brain membrane G proteins of deep-living marine fishes. Comparative Biochemistry and Physiology B 135:697-705.
Siebenaller, J.F. and Garrett, D.J. (2002) The effects of the deep-sea environment on transmembrane signaling. Comparative Biochemistry and Physiology B , 131: 675-694.
Siebenaller, J.F. (2000) The effects of hydrostatic pressure on signal transduction in brain membranes of deep-sea fishes of the genus Coryphaenoides. Fish Physiology and Biochemistry, 23: 99-106.
Stevens, C.K., Siebenaller, J.F. (2000) The effects of hydrostatic pressure on pertussis toxin-catalyzed ribosylation of G proteins from deep-living macrourid fishes. Comparative Biochemistry and Physiology B, 125: 103-114.
P.H. Yancey, R.H. Kelly, A.L. Fyfe-Johnson, M.T. Auñón, V.P. Walker, J.F. Siebenaller (2000) Effects of osmolytes of deep-sea animals on enzyme function and stability under high hydrostatic pressure. In: Science and Technology of High Pressure: Proceedings of AIRAPT-17, pp. 328-330, Manghnani, M.H., W.J. Nellis, M.T. Nicol (eds). Universities Press, Hyderabad, India.
Yancey, P.H. and Siebenaller, J.F. (1999) Trimethylamine oxide stabilizes teleost and mammalian lactate dehydrogenases against inactivation by hydrostatic pressure and trypsinolysis. Journal of Experimental Biology, 202: 3597-3603.
Siebenaller, J.F. and Murray, T.F. (1999) Hydrostatic pressure alters the time course of GTP[S] binding to G proteins in brain membranes from two congeneric marine fishes. Biological Bulletin 197: 388-394.
J.F. Siebenaller and T.F. Murray (1995) The effects of pressure on G protein-coupled signal transduction. In: Biochemistry and Molecular Biology of Fishes, Volume 5. P.W. Hochachka and T.P. Mommsen, editors, Elsevier Press, pp. 147-174.