Eric C. Niederhoffer joined the faculty at Southern Illinois University at Carbondale in August 1990 after working at Los Alamos National Laboratory and the Massachusetts Institute of Technology. He received his Ph.D. in chemistry from Texas A&M University in 1983 and a B.S. in chemistry and a B.A. in history from the University of Rochester in 1979. Dr. Niederhoffer completed four months of teaching and lecturing as a 2000 Fulbright Scholar at Universidad Nacional de Trujillo, Peru. In 2002, he was appointed Director of the Mentored Professional Enrichment Experience (MPEE) for SIU-SOM.
(618) 453-6467
email: eniederhoffer@siumed.edu
Complete CV (pdf file 37K, doc file 66K)
I am interested in the role of metal ions in biological systems. My goal is to understand how metal ions mediate crucial steps in cellular differentiation. The kidney pathogens Proteus mirabilis and Proteus vulgaris are of interest because they are the most common hospital-acquired infection of complicated urinary tracts (i.e., individuals with advanced age or compromised immune systems). Proteus is an interesting microbe because it swarms over surfaces and invades urothelial cells. Swarming is a developmental process (behavior typical of eucaryotes) that responds to changes in soluble iron concentrations. I have been studying a variety of iron- and dioxygen-regulated genes from Proteus and determining the molecular events important in their expression during liquid culture growth, swarming, and invasion of cells. My work has focused on two specific problem areas, regulation of swarming motility and expression of superoxide dismutase isozymes.
Proteus
swarms over solid surfaces and swims through water-filled channels
in the presence of iron and these motilities can be inhibited
by heavy metal ions, iron chelators, and specific osmotic agents.
One of the methods used by Proteus to facilitate surface
locomotion is production of a polysaccharide slime, which acts
to reduce surface friction. I have observed that swarming motility
is dioxygen dependent while swimming motility depends on respiration.
Invasion of urothelial cells, which line the urinary tract, is
being modeled in our laboratory with the use of synthetic basement
membrane protein matrices. I have observed that under conditions
that inhibit swarming cell differentiation there is little colonization
of the matrices, although the bacterium is competent in transport
through the matrix pores. My present interests are concerned with
understanding the molecular function of metal ions in swarmer
cell differentiation, colonization and cellular metabolism.
Proteus expresses a combination of superoxide dismutase isozymes. P. mirabilis appears to produce two iron-containing and one manganese-containing superoxide dismutase (FeSod1, FeSod2, MnSod) while P. vulgaris appears to produce one iron-containing, one manganese-containing, and one copper,zinc-containing superoxide dismutase (FeSod, MnSod, CuZnSod). Production of the Sod isozymes from growing cells is dependent on both dioxygen and soluble iron concentrations. Heavy metal ions affect Sod production and there is differential expression of Sod during cell differentiation. My present interests are concerned with the molecular interactions that control Sod gene expression, especially during swarmer cell differentiation.
View Chime presentation of the superoxide dismutases from Escherichia coli.
Niederhoffer, E. C. Problem-base learning: an experienced tutor's commentary, in press.
Niederhoffer, E. C. 2001. New insights of the structure, catalytic mechanism, and regulation of expression of the iron superoxide dismutase from Escherichia coli K-12. Revista Medica de Trujillo 5:7-12.
Howell, M. L., E. Alsabbagh, J.-F. Ma, U. A. Ochsner, M. G. Klotz, T. J. Beveridge, K. M. Blumenthal, E. C. Niederhoffer, R. E. Morris, G. E. Dean, M. A. Wani, and D. J. Hassett. 2000. AnkB, a periplasmic ankyrin-like protein in Pseudomonas aeruginosa is required for optimal catalase B (KatB) activity and resistance to hydrogen peroxide. J. Bacteriol., 182:4545-4556.
Dayton, T. M., K. A. Diefenbach, M. L. Fuller, J. Valtos, and E. C. Niederhoffer. 1996. Production of superoxide dismutases from Proteus mirabilis and Proteus vulgaris. BioMetals 9:131-137.
Wilkerson, M. L., and E. C. Niederhoffer. 1995. Swarming characteristics of Proteus mirabilis under anaerobic and aerobic conditions. Anaerobe 1:345-350.
Eickhoff, J., E. Potts, J. Valtos, and E. C. Niederhoffer. 1995. Heavy metal effects on Proteus mirabilis superoxide dismutase production. FEMS Microbiol. Lett. 132:271-276.
Rodabough, A., M. S. Foster, and E. C. Niederhoffer. 1995. Plating techniques for extremely thermophilic methanogens, p. 57-60. In F. T. Robb, A. R. Place, K. R. Sowers, H. J. Schreier, S. DasSarma, and E. M. Fleischmann, (eds.), Archaea: a laboratory manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York.
Foster, M. S., J. N. Carroll, and E. C. Niederhoffer. 1994. Phenylalanine- and tyrosine-dependent production of enterobactin in Escherichia coli. FEMS Microbiol. Lett. 117:79-84.
Foster, M. S., A. Rodabough, T. M. Dayton, E. M. Melko, S. S. Szegedi, and E. C. Niederhoffer. 1993. Improved methods for the cultivation of strictly anaerobic, extremely thermophilic methanogens. Biotechniques 16:996-1002.
Foster, M. S., T. S. Conver, A. Rodabough, T. M. Dayton, J. A. Koropchak, and E. C. Niederhoffer. 1993. Speciation and mobilization of toxic heavy metal ions by methanogenic bacteria. Contract ENR-HWR-92-097. Hazardous Waste Research and Information Center, Champaign, IL.
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