Liebolt Chair, University of Arkansas Premedical Program
J. William Fulbright College of Arts & Sciences
Research in my laboratory deals with the biochemical and genetic mechanisms by which bacteria respond to their ionic environment. One focus is on alkaliphilic Bacillus species, which grow at pH 10.5 or higher. These bacteria simultaneously maintain a large reversed pH gradient and high internal ATP concentrations via the actions of sodium/proton antiporters and an unusual ATP synthase. In my laboratory, molecular genetic and biochemical techniques are used to characterize these two enzymatic processes. A second project involves the molecular characterization of ion transporters and other potential virulence determinants in the intestinal pathogen Clostridium difficile. We are characterizing an unusual locus associated with peptide transport. In addition, we have identified, cloned, and sequenced a novel Clostridial cycloserine resistance determinant.
Oxidative phosphorylation in alkaliphilic bacteria, virulence determinants of Clostridium difficile.
Ph.D. University of Georgia, 1987
Ivey, D.M., J. Zemsky, A. A. Guffanti, M. G. Sturr, D. B. Hicks, T. A. Krulwich, R. Gilmour, and M. Ito. 1998. Alkaliphile Bioenergetics, p. 181-210. In K. Horikoshi and W.D. Grant (eds.), Extremophiles: Microbial Life in Extreme Environments. Wiley-Liss, New York.
Das, A., D. M. Ivey, and L. G. Ljungdahl. 1997. Purification and reconstitution into proteoliposomes of the F1F0 ATP synthase from the obligately anaerobic gram-positive bacterium Clostridium thermoautotrophicum. J. Bacteriol. 179:1714-1720.
Ito, M., A. A. Guffanti, J. Zemsky, D. M. Ivey, and T. A. Krulwich. 1997. Role of the nhaCencoded Na+/H+ antiporter of alkaliphilic Bacillus firmus OF4. J. Bacteriol. 179:3851- 3857.
Ivey, D. M., M. G. Sturr, T. A. Krulwich, and D. B. Hicks. 1994. The abundance of atp gene transcript and of the membrane F1FO-ATPase as a function of the growth pH of alkaliphilic Bacillus firmus OF4. J. Bacteriol. 176:5167-5170.
Ivey, D. M., A. A. Guffanti, J. Zemsky, E. Pinner, R. Karpel, E. Padan, S. Schuldiner, and T. A. Krulwich. 1993. Cloning and characterization of a putative Ca2+/H+ antiporter gene from Escherichia coli upon functional complementation of Na+/H+ antiporter-deficient strains by the overexpressed gene. J. Biol. Chem. 268:11296-11303.