Grover Stephens
Professor Emeritus, Ecology & Evolutionary Biology
School of Biological Sciences
School of Biological Sciences
PH.D., Northwestern University
University of California, Irvine
498 SH
Mail Code: 2525
Irvine, CA 92697
498 SH
Mail Code: 2525
Irvine, CA 92697
Research Interests
Amino acid uptake and assimilation by marine invertebrates and algae
Academic Distinctions
Appointments
Research Abstract
The dissolved organic matter in solution in sea water outweighs the total plant and animal biomass on earth by at least a factor of two. However, it is in extremely dilute solution. In unpolluted inshore waters where it is most concentrated, it rarely exceeds a few thousandths of a gram/liter. Of this, the vast bulk is chemically inert. Perhaps as much as 100 micrograms/liter (usually less) consists of amino acids, urea and sugars which can be rapidly taken up and metabolized by marine organisms. For comparison, inorganic salt is present at roughly 33 grams/liter.
Quantitative analysis of the active components was facilitated in the early 1980's with the development of high performance liquid chromatography (HPLC). This made it possible to follow the time course of disappearance of these components of dissolved organic material at natural levels and compare this input with estimates of metabolic needs. It was also necessary to exclude the possibility of bacterial involvement in this disappearance and to provide a reasonable account of the thermodynamics net active transport against; gradients as high as a million to one. Our laboratory has been able to do this and has made a strong case for this active uptake of dissolved organic materials from sea water in both soft-bodied invertebrate animals and selected plytoplankters.
I stopped accepting graduate students in 1988, anticipating my retirement in the summer of 1991. Of the 22 PhD's I have had the pleasure of directing, a number are on the faculty of research institutions and continue contributing strongly to the general areas outlined above.
Quantitative analysis of the active components was facilitated in the early 1980's with the development of high performance liquid chromatography (HPLC). This made it possible to follow the time course of disappearance of these components of dissolved organic material at natural levels and compare this input with estimates of metabolic needs. It was also necessary to exclude the possibility of bacterial involvement in this disappearance and to provide a reasonable account of the thermodynamics net active transport against; gradients as high as a million to one. Our laboratory has been able to do this and has made a strong case for this active uptake of dissolved organic materials from sea water in both soft-bodied invertebrate animals and selected plytoplankters.
I stopped accepting graduate students in 1988, anticipating my retirement in the summer of 1991. Of the 22 PhD's I have had the pleasure of directing, a number are on the faculty of research institutions and continue contributing strongly to the general areas outlined above.
Publications
Qafaiti, M. and G.C. Stephens 1989. Effect of nitrogen depirivation on amino acid uptake by the chlorophyte Platymonas subcordiformia. Marine Biology, 100:515-523.
Davis, J.P., S.Bellis and G.C.Stephens. 1988. Characterization of a broad-scope amino acid transport system in larval and adult sand dollars. American Journal of Physiology, 254:R485-R490.
Qafaiti, M. and G.C. Stephens 1989. Effect of nitrogen depirivation on amino acid uptake by the chlorophyte Platymonas subcordiformia. Marine Biology, 100:515-523
Davis, J.P., S.Bellis and G.C.Stephens. 1988. Characterization of a broad-scope amino acid transport system in larval and adult sand dollars. American Journal of Physiology, 254:R485-R490.
Qafaiti, M. and G.C. Stephens 1989. Effect of nitrogen depirivation on amino acid uptake by the chlorophyte Platymonas subcordiformia. Marine Biology, 100:515-523
Davis, J.P., S.Bellis and G.C.Stephens. 1988. Characterization of a broad-scope amino acid transport isystem in larval and adult sand dollars. American Journal of Physiology, 254:R485-R490.
Stephens, G.C. 1988. Epidermal amino acid transport in marine invertebrates. Biochimica Biophysica Acta, 947:113-138.
Link to this profile
https://faculty.uci.edu/profile/?facultyId=3001
https://faculty.uci.edu/profile/?facultyId=3001
Last updated
02/22/2002
02/22/2002